/*
 *
 * Copyright (c) 2014-2023 The Khronos Group Inc.
 * Copyright (c) 2014-2023 Valve Corporation
 * Copyright (c) 2014-2023 LunarG, Inc.
 * Copyright (C) 2015 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.

 *
 * Author: Jon Ashburn <jon@lunarg.com>
 * Author: Courtney Goeltzenleuchter <courtney@LunarG.com>
 * Author: Mark Young <marky@lunarg.com>
 * Author: Lenny Komow <lenny@lunarg.com>
 * Author: Charles Giessen <charles@lunarg.com>
 *
 */

#include "loader.h"

#include <ctype.h>
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <stdbool.h>
#include <string.h>
#include <stddef.h>

#if defined(__APPLE__)
#include <CoreFoundation/CoreFoundation.h>
#include <sys/param.h>
#endif

#include <sys/types.h>
#if defined(_WIN32)
#include "dirent_on_windows.h"
#else  // _WIN32
#include <dirent.h>
#endif  // _WIN32

#include "allocation.h"
#include "cJSON.h"
#include "debug_utils.h"
#include "loader_environment.h"
#include "gpa_helper.h"
#include "log.h"
#include "unknown_function_handling.h"
#include "vk_loader_platform.h"
#include "wsi.h"

#if defined(WIN32)
#include "loader_windows.h"
#endif
#ifdef LOADER_ENABLE_LINUX_SORT
// This header is currently only used when sorting Linux devices, so don't include it otherwise.
#include "loader_linux.h"
#endif  // LOADER_ENABLE_LINUX_SORT

// Generated file containing all the extension data
#include "vk_loader_extensions.c"

struct loader_struct loader = {0};

struct activated_layer_info {
    char *name;
    char *manifest;
    char *library;
    bool is_implicit;
    char *disable_env;
};

// thread safety lock for accessing global data structures such as "loader"
// all entrypoints on the instance chain need to be locked except GPA
// additionally CreateDevice and DestroyDevice needs to be locked
loader_platform_thread_mutex loader_lock;
loader_platform_thread_mutex loader_json_lock;
loader_platform_thread_mutex loader_preload_icd_lock;
loader_platform_thread_mutex loader_global_instance_list_lock;

// A list of ICDs that gets initialized when the loader does its global initialization. This list should never be used by anything
// other than EnumerateInstanceExtensionProperties(), vkDestroyInstance, and loader_release(). This list does not change
// functionality, but the fact that the libraries already been loaded causes any call that needs to load ICD libraries to speed up
// significantly. This can have a huge impact when making repeated calls to vkEnumerateInstanceExtensionProperties and
// vkCreateInstance.
static struct loader_icd_tramp_list scanned_icds;

LOADER_PLATFORM_THREAD_ONCE_DECLARATION(once_init);

// Creates loader_api_version struct that contains the major and minor fields, setting patch to 0
loader_api_version loader_make_version(uint32_t version) {
    loader_api_version out_version;
    out_version.major = VK_API_VERSION_MAJOR(version);
    out_version.minor = VK_API_VERSION_MINOR(version);
    out_version.patch = 0;
    return out_version;
}

// Creates loader_api_version struct containing the major, minor, and patch fields
loader_api_version loader_make_full_version(uint32_t version) {
    loader_api_version out_version;
    out_version.major = VK_API_VERSION_MAJOR(version);
    out_version.minor = VK_API_VERSION_MINOR(version);
    out_version.patch = VK_API_VERSION_PATCH(version);
    return out_version;
}

loader_api_version loader_combine_version(uint32_t major, uint32_t minor, uint32_t patch) {
    loader_api_version out_version;
    out_version.major = (uint16_t)major;
    out_version.minor = (uint16_t)minor;
    out_version.patch = (uint16_t)patch;
    return out_version;
}

// Helper macros for determining if a version is valid or not
bool loader_check_version_meets_required(loader_api_version required, loader_api_version version) {
    // major version is satisfied
    return (version.major > required.major) ||
           // major version is equal, minor version is patch version is greater to minimum minor
           (version.major == required.major && version.minor > required.minor) ||
           // major and minor version are equal, patch version is greater or equal to minimum patch
           (version.major == required.major && version.minor == required.minor && version.patch >= required.patch);
}

// Wrapper around opendir so that the dirent_on_windows gets the instance it needs
// while linux opendir & readdir does not
DIR *loader_opendir(const struct loader_instance *instance, const char *name) {
#if defined(_WIN32)
    return opendir(instance ? &instance->alloc_callbacks : NULL, name);
#else   // _WIN32
    return opendir(name);
#endif  // _WIN32
}
int loader_closedir(const struct loader_instance *instance, DIR *dir) {
#if defined(_WIN32)
    return closedir(instance ? &instance->alloc_callbacks : NULL, dir);
#else   // _WIN32
    return closedir(dir);
#endif  // _WIN32
}

static bool is_json(const char *path, size_t len) {
    if (len < 5) {
        return false;
    }
    return !strncmp(path, ".json", 5);
}

// Handle error from to library loading
void loader_handle_load_library_error(const struct loader_instance *inst, const char *filename,
                                      enum loader_layer_library_status *lib_status) {
    const char *error_message = loader_platform_open_library_error(filename);
    // If the error is due to incompatible architecture (eg 32 bit vs 64 bit), report it with INFO level
    // Discussed in Github issue 262 & 644
    // "wrong ELF class" is a linux error, " with error 193" is a windows error
    VkFlags err_flag = VULKAN_LOADER_ERROR_BIT;
    if (strstr(error_message, "wrong ELF class:") != NULL || strstr(error_message, " with error 193") != NULL) {
        err_flag = VULKAN_LOADER_INFO_BIT;
        if (NULL != lib_status) {
            *lib_status = LOADER_LAYER_LIB_ERROR_WRONG_BIT_TYPE;
        }
    }
    // Check if the error is due to lack of memory
    // "with error 8" is the windows error code for OOM cases, aka ERROR_NOT_ENOUGH_MEMORY
    // Linux doesn't have such a nice error message - only if there are reported issues should this be called
    else if (strstr(error_message, " with error 8") != NULL) {
        if (NULL != lib_status) {
            *lib_status = LOADER_LAYER_LIB_ERROR_OUT_OF_MEMORY;
        }
    } else if (NULL != lib_status) {
        *lib_status = LOADER_LAYER_LIB_ERROR_FAILED_TO_LOAD;
    }
    loader_log(inst, err_flag, 0, error_message);
}

VKAPI_ATTR VkResult VKAPI_CALL vkSetInstanceDispatch(VkInstance instance, void *object) {
    struct loader_instance *inst = loader_get_instance(instance);
    if (!inst) {
        loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0, "vkSetInstanceDispatch: Can not retrieve Instance dispatch table.");
        return VK_ERROR_INITIALIZATION_FAILED;
    }
    loader_set_dispatch(object, inst->disp);
    return VK_SUCCESS;
}

VKAPI_ATTR VkResult VKAPI_CALL vkSetDeviceDispatch(VkDevice device, void *object) {
    struct loader_device *dev;
    struct loader_icd_term *icd_term = loader_get_icd_and_device(device, &dev, NULL);

    if (NULL == icd_term || NULL == dev) {
        return VK_ERROR_INITIALIZATION_FAILED;
    }
    loader_set_dispatch(object, &dev->loader_dispatch);
    return VK_SUCCESS;
}

void loader_free_layer_properties(const struct loader_instance *inst, struct loader_layer_properties *layer_properties) {
    loader_instance_heap_free(inst, layer_properties->component_layer_names);
    loader_instance_heap_free(inst, layer_properties->override_paths);
    loader_instance_heap_free(inst, layer_properties->blacklist_layer_names);
    loader_instance_heap_free(inst, layer_properties->app_key_paths);

    loader_destroy_generic_list(inst, (struct loader_generic_list *)&layer_properties->instance_extension_list);

    if (layer_properties->device_extension_list.capacity > 0 && NULL != layer_properties->device_extension_list.list) {
        for (uint32_t i = 0; i < layer_properties->device_extension_list.count; i++) {
            struct loader_dev_ext_props *ext_props = &layer_properties->device_extension_list.list[i];
            if (ext_props->entrypoint_count > 0) {
                for (uint32_t j = 0; j < ext_props->entrypoint_count; j++) {
                    loader_instance_heap_free(inst, ext_props->entrypoints[j]);
                }
                loader_instance_heap_free(inst, ext_props->entrypoints);
            }
        }
    }
    loader_destroy_generic_list(inst, (struct loader_generic_list *)&layer_properties->device_extension_list);

    // Make sure to clear out the removed layer, in case new layers are added in the previous location
    memset(layer_properties, 0, sizeof(struct loader_layer_properties));
}

// Combine path elements, separating each element with the platform-specific
// directory separator, and save the combined string to a destination buffer,
// not exceeding the given length. Path elements are given as variable args,
// with a NULL element terminating the list.
//
// \returns the total length of the combined string, not including an ASCII
// NUL termination character. This length may exceed the available storage:
// in this case, the written string will be truncated to avoid a buffer
// overrun, and the return value will greater than or equal to the storage
// size. A NULL argument may be provided as the destination buffer in order
// to determine the required string length without actually writing a string.
static size_t loader_platform_combine_path(char *dest, size_t len, ...) {
    size_t required_len = 0;
    va_list ap;
    const char *component;

    va_start(ap, len);
    component = va_arg(ap, const char *);
    while (component) {
        if (required_len > 0) {
            // This path element is not the first non-empty element; prepend
            // a directory separator if space allows
            if (dest && required_len + 1 < len) {
                (void)snprintf(dest + required_len, len - required_len, "%c", DIRECTORY_SYMBOL);
            }
            required_len++;
        }

        if (dest && required_len < len) {
            strncpy(dest + required_len, component, len - required_len);
        }
        required_len += strlen(component);
        component = va_arg(ap, const char *);
    }

    va_end(ap);

    // strncpy(3) won't add a NUL terminating byte in the event of truncation.
    if (dest && required_len >= len) {
        dest[len - 1] = '\0';
    }

    return required_len;
}

// Given string of three part form "maj.min.pat" convert to a vulkan version number.
// Also can understand four part form "variant.major.minor.patch" if provided.
static uint32_t loader_parse_version_string(char *vers_str) {
    uint32_t variant = 0, major = 0, minor = 0, patch = 0;
    char *vers_tok;

    if (!vers_str) {
        return 0;
    }

    vers_tok = strtok(vers_str, ".\"\n\r");
    if (NULL != vers_tok) {
        major = (uint16_t)atoi(vers_tok);
        vers_tok = strtok(NULL, ".\"\n\r");
        if (NULL != vers_tok) {
            minor = (uint16_t)atoi(vers_tok);
            vers_tok = strtok(NULL, ".\"\n\r");
            if (NULL != vers_tok) {
                patch = (uint16_t)atoi(vers_tok);
                vers_tok = strtok(NULL, ".\"\n\r");
                // check that we are using a 4 part version string
                if (NULL != vers_tok) {
                    // if we are, move the values over into the correct place
                    variant = major;
                    major = minor;
                    minor = patch;
                    patch = (uint16_t)atoi(vers_tok);
                }
            }
        }
    }

    return VK_MAKE_API_VERSION(variant, major, minor, patch);
}

bool compare_vk_extension_properties(const VkExtensionProperties *op1, const VkExtensionProperties *op2) {
    return strcmp(op1->extensionName, op2->extensionName) == 0 ? true : false;
}

// Search the given ext_array for an extension matching the given vk_ext_prop
bool has_vk_extension_property_array(const VkExtensionProperties *vk_ext_prop, const uint32_t count,
                                     const VkExtensionProperties *ext_array) {
    for (uint32_t i = 0; i < count; i++) {
        if (compare_vk_extension_properties(vk_ext_prop, &ext_array[i])) return true;
    }
    return false;
}

// Search the given ext_list for an extension matching the given vk_ext_prop
bool has_vk_extension_property(const VkExtensionProperties *vk_ext_prop, const struct loader_extension_list *ext_list) {
    for (uint32_t i = 0; i < ext_list->count; i++) {
        if (compare_vk_extension_properties(&ext_list->list[i], vk_ext_prop)) return true;
    }
    return false;
}

// Search the given ext_list for a device extension matching the given ext_prop
bool has_vk_dev_ext_property(const VkExtensionProperties *ext_prop, const struct loader_device_extension_list *ext_list) {
    for (uint32_t i = 0; i < ext_list->count; i++) {
        if (compare_vk_extension_properties(&ext_list->list[i].props, ext_prop)) return true;
    }
    return false;
}

// Get the next unused layer property in the list. Init the property to zero.
static struct loader_layer_properties *loader_get_next_layer_property_slot(const struct loader_instance *inst,
                                                                           struct loader_layer_list *layer_list) {
    if (layer_list->capacity == 0) {
        layer_list->list =
            loader_instance_heap_calloc(inst, sizeof(struct loader_layer_properties) * 64, VK_SYSTEM_ALLOCATION_SCOPE_INSTANCE);
        if (layer_list->list == NULL) {
            loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                       "loader_get_next_layer_property_slot: Out of memory can not add any layer properties to list");
            return NULL;
        }
        layer_list->capacity = sizeof(struct loader_layer_properties) * 64;
    }

    // Ensure enough room to add an entry
    if ((layer_list->count + 1) * sizeof(struct loader_layer_properties) > layer_list->capacity) {
        void *new_ptr = loader_instance_heap_realloc(inst, layer_list->list, layer_list->capacity, layer_list->capacity * 2,
                                                     VK_SYSTEM_ALLOCATION_SCOPE_INSTANCE);
        if (NULL == new_ptr) {
            loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0, "loader_get_next_layer_property_slot: realloc failed for layer list");
            return NULL;
        }
        layer_list->list = new_ptr;
        memset((uint8_t *)layer_list->list + layer_list->capacity, 0, layer_list->capacity);
        layer_list->capacity *= 2;
    }

    layer_list->count++;
    return &(layer_list->list[layer_list->count - 1]);
}

// Search the given layer list for a layer property matching the given layer name
static struct loader_layer_properties *loader_find_layer_property(const char *name, const struct loader_layer_list *layer_list) {
    for (uint32_t i = 0; i < layer_list->count; i++) {
        const VkLayerProperties *item = &layer_list->list[i].info;
        if (strcmp(name, item->layerName) == 0) return &layer_list->list[i];
    }
    return NULL;
}

// Search the given layer list for a layer matching the given layer name
static bool loader_find_layer_name_in_list(const char *name, const struct loader_layer_list *layer_list) {
    if (NULL == layer_list) {
        return false;
    }
    if (NULL != loader_find_layer_property(name, layer_list)) {
        return true;
    }
    return false;
}

// Search the given meta-layer's component list for a layer matching the given layer name
static bool loader_find_layer_name_in_meta_layer(const struct loader_instance *inst, const char *layer_name,
                                                 struct loader_layer_list *layer_list,
                                                 struct loader_layer_properties *meta_layer_props) {
    for (uint32_t comp_layer = 0; comp_layer < meta_layer_props->num_component_layers; comp_layer++) {
        if (!strcmp(meta_layer_props->component_layer_names[comp_layer], layer_name)) {
            return true;
        }
        struct loader_layer_properties *comp_layer_props =
            loader_find_layer_property(meta_layer_props->component_layer_names[comp_layer], layer_list);
        if (comp_layer_props->type_flags & VK_LAYER_TYPE_FLAG_META_LAYER) {
            return loader_find_layer_name_in_meta_layer(inst, layer_name, layer_list, comp_layer_props);
        }
    }
    return false;
}

// Search the override layer's blacklist for a layer matching the given layer name
static bool loader_find_layer_name_in_blacklist(const struct loader_instance *inst, const char *layer_name,
                                                struct loader_layer_list *layer_list,
                                                struct loader_layer_properties *meta_layer_props) {
    for (uint32_t black_layer = 0; black_layer < meta_layer_props->num_blacklist_layers; ++black_layer) {
        if (!strcmp(meta_layer_props->blacklist_layer_names[black_layer], layer_name)) {
            return true;
        }
    }
    return false;
}

// Remove all layer properties entries from the list
void loader_delete_layer_list_and_properties(const struct loader_instance *inst, struct loader_layer_list *layer_list) {
    uint32_t i;
    if (!layer_list) return;

    for (i = 0; i < layer_list->count; i++) {
        loader_free_layer_properties(inst, &(layer_list->list[i]));
    }
    layer_list->count = 0;

    if (layer_list->capacity > 0) {
        layer_list->capacity = 0;
        loader_instance_heap_free(inst, layer_list->list);
    }
}

void loader_remove_layer_in_list(const struct loader_instance *inst, struct loader_layer_list *layer_list,
                                 uint32_t layer_to_remove) {
    if (layer_list == NULL || layer_to_remove >= layer_list->count) {
        return;
    }
    loader_free_layer_properties(inst, &(layer_list->list[layer_to_remove]));

    // Remove the current invalid meta-layer from the layer list.  Use memmove since we are
    // overlapping the source and destination addresses.
    memmove(&layer_list->list[layer_to_remove], &layer_list->list[layer_to_remove + 1],
            sizeof(struct loader_layer_properties) * (layer_list->count - 1 - layer_to_remove));

    // Decrement the count (because we now have one less) and decrement the loop index since we need to
    // re-check this index.
    layer_list->count--;
}

// Remove all layers in the layer list that are blacklisted by the override layer.
// NOTE: This should only be called if an override layer is found and not expired.
void loader_remove_layers_in_blacklist(const struct loader_instance *inst, struct loader_layer_list *layer_list) {
    struct loader_layer_properties *override_prop = loader_find_layer_property(VK_OVERRIDE_LAYER_NAME, layer_list);
    if (NULL == override_prop) {
        return;
    }

    for (int32_t j = 0; j < (int32_t)(layer_list->count); j++) {
        struct loader_layer_properties cur_layer_prop = layer_list->list[j];
        const char *cur_layer_name = &cur_layer_prop.info.layerName[0];

        // Skip the override layer itself.
        if (!strcmp(VK_OVERRIDE_LAYER_NAME, cur_layer_name)) {
            continue;
        }

        // If found in the override layer's blacklist, remove it
        if (loader_find_layer_name_in_blacklist(inst, cur_layer_name, layer_list, override_prop)) {
            loader_log(inst, VULKAN_LOADER_DEBUG_BIT, 0,
                       "loader_remove_layers_in_blacklist: Override layer is active and layer %s is in the blacklist inside of it. "
                       "Removing that layer from current layer list.",
                       cur_layer_name);
            loader_remove_layer_in_list(inst, layer_list, j);
            j--;

            // Re-do the query for the override layer
            override_prop = loader_find_layer_property(VK_OVERRIDE_LAYER_NAME, layer_list);
        }
    }
}

// Remove all layers in the layer list that are not found inside any implicit meta-layers.
void loader_remove_layers_not_in_implicit_meta_layers(const struct loader_instance *inst, struct loader_layer_list *layer_list) {
    int32_t i;
    int32_t j;
    int32_t layer_count = (int32_t)(layer_list->count);

    for (i = 0; i < layer_count; i++) {
        layer_list->list[i].keep = false;
    }

    for (i = 0; i < layer_count; i++) {
        struct loader_layer_properties *cur_layer_prop = &layer_list->list[i];

        if (0 == (cur_layer_prop->type_flags & VK_LAYER_TYPE_FLAG_EXPLICIT_LAYER)) {
            cur_layer_prop->keep = true;
            continue;
        }
        for (j = 0; j < layer_count; j++) {
            struct loader_layer_properties *layer_to_check = &layer_list->list[j];

            if (i == j) {
                continue;
            }

            if (layer_to_check->type_flags & VK_LAYER_TYPE_FLAG_META_LAYER) {
                // For all layers found in this meta layer, we want to keep them as well.
                if (loader_find_layer_name_in_meta_layer(inst, cur_layer_prop->info.layerName, layer_list, layer_to_check)) {
                    cur_layer_prop->keep = true;
                }
            }
        }
    }

    // Remove any layers we don't want to keep (Don't use layer_count here as we need it to be
    // dynamically updated if we delete a layer property in the list).
    for (i = 0; i < (int32_t)(layer_list->count); i++) {
        struct loader_layer_properties *cur_layer_prop = &layer_list->list[i];
        if (!cur_layer_prop->keep) {
            loader_log(
                inst, VULKAN_LOADER_DEBUG_BIT, 0,
                "loader_remove_layers_not_in_implicit_meta_layers : Implicit meta-layers are active, and layer %s is not list "
                "inside of any.  So removing layer from current layer list.",
                cur_layer_prop->info.layerName);
            loader_remove_layer_in_list(inst, layer_list, i);
            i--;
        }
    }
}

static VkResult loader_add_instance_extensions(const struct loader_instance *inst,
                                               const PFN_vkEnumerateInstanceExtensionProperties fp_get_props, const char *lib_name,
                                               struct loader_extension_list *ext_list) {
    uint32_t i, count = 0;
    VkExtensionProperties *ext_props;
    VkResult res = VK_SUCCESS;

    if (!fp_get_props) {
        // No EnumerateInstanceExtensionProperties defined
        goto out;
    }

    // Make sure we never call ourself by accident, this should never happen outside of error paths
    if (fp_get_props == vkEnumerateInstanceExtensionProperties) {
        loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                   "loader_add_instance_extensions: %s's vkEnumerateInstanceExtensionProperties points to the loader, this would "
                   "lead to infinite recursion.",
                   lib_name);
        goto out;
    }

    res = fp_get_props(NULL, &count, NULL);
    if (res != VK_SUCCESS) {
        loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                   "loader_add_instance_extensions: Error getting Instance extension count from %s", lib_name);
        goto out;
    }

    if (count == 0) {
        // No ExtensionProperties to report
        goto out;
    }

    ext_props = loader_stack_alloc(count * sizeof(VkExtensionProperties));
    if (NULL == ext_props) {
        res = VK_ERROR_OUT_OF_HOST_MEMORY;
        goto out;
    }

    res = fp_get_props(NULL, &count, ext_props);
    if (res != VK_SUCCESS) {
        loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0, "loader_add_instance_extensions: Error getting Instance extensions from %s",
                   lib_name);
        goto out;
    }

    for (i = 0; i < count; i++) {
        bool ext_unsupported = wsi_unsupported_instance_extension(&ext_props[i]);
        if (!ext_unsupported) {
            res = loader_add_to_ext_list(inst, ext_list, 1, &ext_props[i]);
            if (res != VK_SUCCESS) {
                goto out;
            }
        }
    }

out:
    return res;
}

VkResult loader_add_device_extensions(const struct loader_instance *inst,
                                      PFN_vkEnumerateDeviceExtensionProperties fpEnumerateDeviceExtensionProperties,
                                      VkPhysicalDevice physical_device, const char *lib_name,
                                      struct loader_extension_list *ext_list) {
    uint32_t i = 0, count = 0;
    VkResult res = VK_SUCCESS;
    VkExtensionProperties *ext_props = NULL;

    res = fpEnumerateDeviceExtensionProperties(physical_device, NULL, &count, NULL);
    if (res != VK_SUCCESS) {
        loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                   "loader_add_device_extensions: Error getting physical device extension info count from library %s", lib_name);
        return res;
    }
    if (count > 0) {
        ext_props = loader_stack_alloc(count * sizeof(VkExtensionProperties));
        if (!ext_props) {
            loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                       "loader_add_device_extensions: Failed to allocate space for device extension properties from library %s.",
                       lib_name);
            return VK_ERROR_OUT_OF_HOST_MEMORY;
        }
        res = fpEnumerateDeviceExtensionProperties(physical_device, NULL, &count, ext_props);
        if (res != VK_SUCCESS) {
            return res;
        }
        for (i = 0; i < count; i++) {
            res = loader_add_to_ext_list(inst, ext_list, 1, &ext_props[i]);
            if (res != VK_SUCCESS) {
                return res;
            }
        }
    }

    return VK_SUCCESS;
}

VkResult loader_init_generic_list(const struct loader_instance *inst, struct loader_generic_list *list_info, size_t element_size) {
    size_t capacity = 32 * element_size;
    list_info->count = 0;
    list_info->capacity = 0;
    list_info->list = loader_instance_heap_calloc(inst, capacity, VK_SYSTEM_ALLOCATION_SCOPE_INSTANCE);
    if (list_info->list == NULL) {
        loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0, "loader_init_generic_list: Failed to allocate space for generic list");
        return VK_ERROR_OUT_OF_HOST_MEMORY;
    }
    list_info->capacity = capacity;
    return VK_SUCCESS;
}

void loader_destroy_generic_list(const struct loader_instance *inst, struct loader_generic_list *list) {
    loader_instance_heap_free(inst, list->list);
    list->count = 0;
    list->capacity = 0;
    list->list = NULL;
}

// Append non-duplicate extension properties defined in props to the given ext_list.
// Return - Vk_SUCCESS on success
VkResult loader_add_to_ext_list(const struct loader_instance *inst, struct loader_extension_list *ext_list,
                                uint32_t prop_list_count, const VkExtensionProperties *props) {
    uint32_t i;
    const VkExtensionProperties *cur_ext;

    if (ext_list->list == NULL || ext_list->capacity == 0) {
        VkResult res = loader_init_generic_list(inst, (struct loader_generic_list *)ext_list, sizeof(VkExtensionProperties));
        if (VK_SUCCESS != res) {
            return res;
        }
    }

    for (i = 0; i < prop_list_count; i++) {
        cur_ext = &props[i];

        // look for duplicates
        if (has_vk_extension_property(cur_ext, ext_list)) {
            continue;
        }

        // add to list at end
        // check for enough capacity
        if (ext_list->count * sizeof(VkExtensionProperties) >= ext_list->capacity) {
            void *new_ptr = loader_instance_heap_realloc(inst, ext_list->list, ext_list->capacity, ext_list->capacity * 2,
                                                         VK_SYSTEM_ALLOCATION_SCOPE_INSTANCE);
            if (new_ptr == NULL) {
                loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                           "loader_add_to_ext_list: Failed to reallocate space for extension list");
                return VK_ERROR_OUT_OF_HOST_MEMORY;
            }
            ext_list->list = new_ptr;

            // double capacity
            ext_list->capacity *= 2;
        }

        memcpy(&ext_list->list[ext_list->count], cur_ext, sizeof(VkExtensionProperties));
        ext_list->count++;
    }
    return VK_SUCCESS;
}

// Append one extension property defined in props with entrypoints defined in entries to the given
// ext_list. Do not append if a duplicate.
// Return - Vk_SUCCESS on success
VkResult loader_add_to_dev_ext_list(const struct loader_instance *inst, struct loader_device_extension_list *ext_list,
                                    const VkExtensionProperties *props, uint32_t entry_count, char **entrys) {
    uint32_t idx;
    if (ext_list->list == NULL || ext_list->capacity == 0) {
        VkResult res = loader_init_generic_list(inst, (struct loader_generic_list *)ext_list, sizeof(struct loader_dev_ext_props));
        if (VK_SUCCESS != res) {
            return res;
        }
    }

    // look for duplicates
    if (has_vk_dev_ext_property(props, ext_list)) {
        return VK_SUCCESS;
    }

    idx = ext_list->count;
    // add to list at end
    // check for enough capacity
    if (idx * sizeof(struct loader_dev_ext_props) >= ext_list->capacity) {
        void *new_ptr = loader_instance_heap_realloc(inst, ext_list->list, ext_list->capacity, ext_list->capacity * 2,
                                                     VK_SYSTEM_ALLOCATION_SCOPE_INSTANCE);

        if (NULL == new_ptr) {
            loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                       "loader_add_to_dev_ext_list: Failed to reallocate space for device extension list");
            return VK_ERROR_OUT_OF_HOST_MEMORY;
        }
        ext_list->list = new_ptr;

        // double capacity
        ext_list->capacity *= 2;
    }

    memcpy(&ext_list->list[idx].props, props, sizeof(*props));
    ext_list->list[idx].entrypoint_count = entry_count;
    if (entry_count == 0) {
        ext_list->list[idx].entrypoints = NULL;
    } else {
        ext_list->list[idx].entrypoints =
            loader_instance_heap_alloc(inst, sizeof(char *) * entry_count, VK_SYSTEM_ALLOCATION_SCOPE_INSTANCE);
        if (ext_list->list[idx].entrypoints == NULL) {
            loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                       "loader_add_to_dev_ext_list: Failed to allocate space for device extension entrypoint list in list %d", idx);
            ext_list->list[idx].entrypoint_count = 0;
            return VK_ERROR_OUT_OF_HOST_MEMORY;
        }
        for (uint32_t i = 0; i < entry_count; i++) {
            ext_list->list[idx].entrypoints[i] =
                loader_instance_heap_alloc(inst, strlen(entrys[i]) + 1, VK_SYSTEM_ALLOCATION_SCOPE_INSTANCE);
            if (ext_list->list[idx].entrypoints[i] == NULL) {
                for (uint32_t j = 0; j < i; j++) {
                    loader_instance_heap_free(inst, ext_list->list[idx].entrypoints[j]);
                }
                loader_instance_heap_free(inst, ext_list->list[idx].entrypoints);
                ext_list->list[idx].entrypoint_count = 0;
                ext_list->list[idx].entrypoints = NULL;
                loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                           "loader_add_to_dev_ext_list: Failed to allocate space for device extension entrypoint %d name", i);
                return VK_ERROR_OUT_OF_HOST_MEMORY;
            }
            strcpy(ext_list->list[idx].entrypoints[i], entrys[i]);
        }
    }
    ext_list->count++;

    return VK_SUCCESS;
}

// Manage lists of VkLayerProperties
static bool loader_init_layer_list(const struct loader_instance *inst, struct loader_layer_list *list) {
    list->capacity = 32 * sizeof(struct loader_layer_properties);
    list->list = loader_instance_heap_calloc(inst, list->capacity, VK_SYSTEM_ALLOCATION_SCOPE_INSTANCE);
    if (list->list == NULL) {
        return false;
    }
    list->count = 0;
    return true;
}

// Search the given array of layer names for an entry matching the given VkLayerProperties
bool loader_names_array_has_layer_property(const VkLayerProperties *vk_layer_prop, uint32_t layer_info_count,
                                           struct activated_layer_info *layer_info) {
    for (uint32_t i = 0; i < layer_info_count; i++) {
        if (strcmp(vk_layer_prop->layerName, layer_info[i].name) == 0) {
            return true;
        }
    }
    return false;
}

void loader_destroy_layer_list(const struct loader_instance *inst, struct loader_device *device,
                               struct loader_layer_list *layer_list) {
    if (device) {
        loader_device_heap_free(device, layer_list->list);
    } else {
        loader_instance_heap_free(inst, layer_list->list);
    }
    layer_list->count = 0;
    layer_list->capacity = 0;
    layer_list->list = NULL;
}

// Append layer properties defined in prop_list to the given layer_info list
VkResult loader_add_layer_properties_to_list(const struct loader_instance *inst, struct loader_layer_list *list,
                                             uint32_t prop_list_count, const struct loader_layer_properties *props) {
    uint32_t i;
    struct loader_layer_properties *layer;

    if (list->list == NULL || list->capacity == 0) {
        if (!loader_init_layer_list(inst, list)) {
            return VK_ERROR_OUT_OF_HOST_MEMORY;
        }
    }

    if (list->list == NULL) return VK_SUCCESS;

    for (i = 0; i < prop_list_count; i++) {
        layer = (struct loader_layer_properties *)&props[i];

        // Check for enough capacity
        if (((list->count + 1) * sizeof(struct loader_layer_properties)) >= list->capacity) {
            size_t new_capacity = list->capacity * 2;
            void *new_ptr =
                loader_instance_heap_realloc(inst, list->list, list->capacity, new_capacity, VK_SYSTEM_ALLOCATION_SCOPE_INSTANCE);
            if (NULL == new_ptr) {
                loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                           "loader_add_layer_properties_to_list: Realloc failed for when attempting to add new layer");
                return VK_ERROR_OUT_OF_HOST_MEMORY;
            }
            list->list = new_ptr;
            list->capacity = new_capacity;
        }

        memcpy(&list->list[list->count], layer, sizeof(struct loader_layer_properties));
        list->count++;
    }

    return VK_SUCCESS;
}

// Determine if the provided explicit layer should be available by querying the appropriate environmental variables.
bool loader_layer_is_available(const struct loader_instance *inst, const struct loader_envvar_filter *enable_filter,
                               const struct loader_envvar_disable_layers_filter *disable_filter,
                               const struct loader_layer_properties *prop) {
    bool available = true;
    if (NULL != disable_filter) {
        bool is_implicit = (0 == (prop->type_flags & VK_LAYER_TYPE_FLAG_EXPLICIT_LAYER));
        bool disabled_by_type = (is_implicit) ? (disable_filter->disable_all_implicit) : (disable_filter->disable_all_explicit);
        if (disable_filter->disable_all || disabled_by_type ||
            check_name_matches_filter_environment_var(inst, prop->info.layerName, &disable_filter->additional_filters)) {
            available = false;
        }
    }
    if (NULL != enable_filter && check_name_matches_filter_environment_var(inst, prop->info.layerName, enable_filter)) {
        available = true;
    } else if (!available) {
        loader_log(inst, VULKAN_LOADER_WARN_BIT | VULKAN_LOADER_LAYER_BIT, 0,
                   "Layer \"%s\" forced disabled because name matches filter of env var \'%s\'.", prop->info.layerName,
                   VK_LAYERS_DISABLE_ENV_VAR);
    }

    return available;
}

// Search the given search_list for any layers in the props list.  Add these to the
// output layer_list.
static VkResult loader_add_layer_names_to_list(const struct loader_instance *inst, const struct loader_envvar_filter *enable_filter,
                                               const struct loader_envvar_disable_layers_filter *disable_filter,
                                               struct loader_layer_list *output_list,
                                               struct loader_layer_list *expanded_output_list, uint32_t name_count,
                                               const char *const *names, const struct loader_layer_list *source_list) {
    struct loader_layer_properties *layer_prop;
    VkResult err = VK_SUCCESS;

    for (uint32_t i = 0; i < name_count; i++) {
        const char *source_name = names[i];

        layer_prop = loader_find_layer_property(source_name, source_list);
        if (NULL == layer_prop) {
            loader_log(inst, VULKAN_LOADER_ERROR_BIT | VULKAN_LOADER_LAYER_BIT, 0,
                       "loader_add_layer_names_to_list: Unable to find layer \"%s\"", source_name);
            err = VK_ERROR_LAYER_NOT_PRESENT;
            continue;
        }

        // Make sure the layer isn't already in the output_list, skip adding it if it is.
        if (loader_find_layer_name_in_list(source_name, output_list)) {
            continue;
        }

        if (!loader_layer_is_available(inst, enable_filter, disable_filter, layer_prop)) {
            continue;
        }

        // If not a meta-layer, simply add it.
        if (0 == (layer_prop->type_flags & VK_LAYER_TYPE_FLAG_META_LAYER)) {
            err = loader_add_layer_properties_to_list(inst, output_list, 1, layer_prop);
            if (err == VK_ERROR_OUT_OF_HOST_MEMORY) return err;
            err = loader_add_layer_properties_to_list(inst, expanded_output_list, 1, layer_prop);
            if (err == VK_ERROR_OUT_OF_HOST_MEMORY) return err;
        } else {
            err = loader_add_meta_layer(inst, enable_filter, disable_filter, layer_prop, output_list, expanded_output_list,
                                        source_list, NULL);
            if (err == VK_ERROR_OUT_OF_HOST_MEMORY) return err;
        }
    }

    return err;
}

// Determine if the provided implicit layer should be enabled by querying the appropriate environmental variables.
// For an implicit layer, at least a disable environment variable is required.
bool loader_implicit_layer_is_enabled(const struct loader_instance *inst, const struct loader_envvar_filter *enable_filter,
                                      const struct loader_envvar_disable_layers_filter *disable_filter,
                                      const struct loader_layer_properties *prop) {
    bool enable = false;
    bool forced_disabled = false;
    bool forced_enabled = false;
    char *env_value = NULL;

    if ((NULL != disable_filter &&
         (disable_filter->disable_all || disable_filter->disable_all_implicit ||
          check_name_matches_filter_environment_var(inst, prop->info.layerName, &disable_filter->additional_filters)))) {
        forced_disabled = true;
    }
    if (NULL != enable_filter && check_name_matches_filter_environment_var(inst, prop->info.layerName, enable_filter)) {
        forced_enabled = true;
    }

    // If no enable_environment variable is specified, this implicit layer is always be enabled by default.
    if (prop->enable_env_var.name[0] == 0) {
        enable = true;
    } else {
        env_value = loader_getenv(prop->enable_env_var.name, inst);
        if (env_value && !strcmp(prop->enable_env_var.value, env_value)) {
            enable = true;
        }

        // Otherwise, only enable this layer if the enable environment variable is defined
        loader_free_getenv(env_value, inst);
    }

    if (forced_enabled) {
        // Only report a message that we've forced on a layer if it wouldn't have been enabled
        // normally.
        if (!enable) {
            enable = true;
            loader_log(inst, VULKAN_LOADER_WARN_BIT | VULKAN_LOADER_LAYER_BIT, 0,
                       "Implicit layer \"%s\" forced enabled due to env var \'%s\'.", prop->info.layerName,
                       VK_LAYERS_ENABLE_ENV_VAR);
        }
    } else if (enable && forced_disabled) {
        enable = false;
        // Report a message that we've forced off a layer if it would have been enabled normally.
        loader_log(inst, VULKAN_LOADER_WARN_BIT | VULKAN_LOADER_LAYER_BIT, 0,
                   "Implicit layer \"%s\" forced disabled because name matches filter of env var \'%s\'.", prop->info.layerName,
                   VK_LAYERS_DISABLE_ENV_VAR);
        return false;
    }

    // The disable_environment has priority over everything else.  If it is defined, the layer is always
    // disabled.
    env_value = loader_getenv(prop->disable_env_var.name, inst);
    if (NULL != env_value) {
        enable = false;
    }
    loader_free_getenv(env_value, inst);

    // Enable this layer if it is included in the override layer
    if (inst != NULL && inst->override_layer_present) {
        struct loader_layer_properties *override = NULL;
        for (uint32_t i = 0; i < inst->instance_layer_list.count; ++i) {
            if (strcmp(inst->instance_layer_list.list[i].info.layerName, VK_OVERRIDE_LAYER_NAME) == 0) {
                override = &inst->instance_layer_list.list[i];
                break;
            }
        }
        if (override != NULL) {
            for (uint32_t i = 0; i < override->num_component_layers; ++i) {
                if (strcmp(override->component_layer_names[i], prop->info.layerName) == 0) {
                    enable = true;
                    break;
                }
            }
        }
    }

    return enable;
}

// Check the individual implicit layer for the enable/disable environment variable settings.  Only add it after
// every check has passed indicating it should be used.
static VkResult loader_add_implicit_layer(const struct loader_instance *inst, const struct loader_layer_properties *prop,
                                          const struct loader_envvar_filter *enable_filter,
                                          const struct loader_envvar_disable_layers_filter *disable_filter,
                                          struct loader_layer_list *target_list, struct loader_layer_list *expanded_target_list,
                                          const struct loader_layer_list *source_list) {
    VkResult result = VK_SUCCESS;
    if (loader_implicit_layer_is_enabled(inst, enable_filter, disable_filter, prop)) {
        if (0 == (prop->type_flags & VK_LAYER_TYPE_FLAG_META_LAYER)) {
            result = loader_add_layer_properties_to_list(inst, target_list, 1, prop);
            if (result == VK_ERROR_OUT_OF_HOST_MEMORY) return result;
            if (NULL != expanded_target_list) {
                result = loader_add_layer_properties_to_list(inst, expanded_target_list, 1, prop);
            }
        } else {
            result = loader_add_meta_layer(inst, enable_filter, disable_filter, prop, target_list, expanded_target_list,
                                           source_list, NULL);
        }
    }
    return result;
}

// Add the component layers of a meta-layer to the active list of layers
VkResult loader_add_meta_layer(const struct loader_instance *inst, const struct loader_envvar_filter *enable_filter,
                               const struct loader_envvar_disable_layers_filter *disable_filter,
                               const struct loader_layer_properties *prop, struct loader_layer_list *target_list,
                               struct loader_layer_list *expanded_target_list, const struct loader_layer_list *source_list,
                               bool *out_found_all_component_layers) {
    VkResult result = VK_SUCCESS;
    bool found_all_component_layers = true;

    // We need to add all the individual component layers
    loader_api_version meta_layer_api_version = loader_make_version(prop->info.specVersion);
    for (uint32_t comp_layer = 0; comp_layer < prop->num_component_layers; comp_layer++) {
        const struct loader_layer_properties *search_prop =
            loader_find_layer_property(prop->component_layer_names[comp_layer], source_list);
        if (search_prop != NULL) {
            loader_api_version search_prop_version = loader_make_version(prop->info.specVersion);
            if (!loader_check_version_meets_required(meta_layer_api_version, search_prop_version)) {
                loader_log(inst, VULKAN_LOADER_WARN_BIT | VULKAN_LOADER_LAYER_BIT, 0,
                           "Meta-layer \"%s\" API version %u.%u, component layer \"%s\" version %u.%u, may have "
                           "incompatibilities (Policy #LLP_LAYER_8)!",
                           prop->info.layerName, meta_layer_api_version.major, meta_layer_api_version.minor,
                           search_prop->info.layerName, search_prop_version.major, search_prop_version.minor);
            }

            if (!loader_layer_is_available(inst, enable_filter, disable_filter, search_prop)) {
                loader_log(inst, VULKAN_LOADER_WARN_BIT | VULKAN_LOADER_LAYER_BIT, 0,
                           "Meta Layer \"%s\" component layer \"%s\" disabled.", prop->info.layerName, search_prop->info.layerName);
                continue;
            }

            // If the component layer is itself an implicit layer, we need to do the implicit layer enable
            // checks
            if (0 == (search_prop->type_flags & VK_LAYER_TYPE_FLAG_EXPLICIT_LAYER)) {
                result = loader_add_implicit_layer(inst, search_prop, enable_filter, disable_filter, target_list,
                                                   expanded_target_list, source_list);
                if (result == VK_ERROR_OUT_OF_HOST_MEMORY) return result;
            } else {
                if (0 != (search_prop->type_flags & VK_LAYER_TYPE_FLAG_META_LAYER)) {
                    bool found_layers_in_component_meta_layer = true;
                    result = loader_add_meta_layer(inst, enable_filter, disable_filter, search_prop, target_list,
                                                   expanded_target_list, source_list, &found_layers_in_component_meta_layer);
                    if (result == VK_ERROR_OUT_OF_HOST_MEMORY) return result;
                    if (!found_layers_in_component_meta_layer) found_all_component_layers = false;
                } else {
                    result = loader_add_layer_properties_to_list(inst, target_list, 1, search_prop);
                    if (result == VK_ERROR_OUT_OF_HOST_MEMORY) return result;
                    if (NULL != expanded_target_list) {
                        result = loader_add_layer_properties_to_list(inst, expanded_target_list, 1, search_prop);
                        if (result == VK_ERROR_OUT_OF_HOST_MEMORY) return result;
                    }
                }
            }
        } else {
            loader_log(inst, VULKAN_LOADER_WARN_BIT | VULKAN_LOADER_LAYER_BIT, 0,
                       "Failed to find layer name \"%s\" component layer \"%s\" to activate (Policy #LLP_LAYER_7)",
                       prop->component_layer_names[comp_layer], prop->component_layer_names[comp_layer]);
            found_all_component_layers = false;
        }
    }

    // Add this layer to the overall target list (not the expanded one)
    if (found_all_component_layers) {
        result = loader_add_layer_properties_to_list(inst, target_list, 1, prop);
        if (result == VK_ERROR_OUT_OF_HOST_MEMORY) return result;
        // Write the result to out_found_all_component_layers in case this function is being recursed
        if (out_found_all_component_layers) *out_found_all_component_layers = found_all_component_layers;
    }

    return result;
}

static VkExtensionProperties *get_extension_property(const char *name, const struct loader_extension_list *list) {
    for (uint32_t i = 0; i < list->count; i++) {
        if (strcmp(name, list->list[i].extensionName) == 0) return &list->list[i];
    }
    return NULL;
}

static VkExtensionProperties *get_dev_extension_property(const char *name, const struct loader_device_extension_list *list) {
    for (uint32_t i = 0; i < list->count; i++) {
        if (strcmp(name, list->list[i].props.extensionName) == 0) return &list->list[i].props;
    }
    return NULL;
}

// For Instance extensions implemented within the loader (i.e. DEBUG_REPORT
// the extension must provide two entry points for the loader to use:
// - "trampoline" entry point - this is the address returned by GetProcAddr
//                              and will always do what's necessary to support a
//                              global call.
// - "terminator" function    - this function will be put at the end of the
//                              instance chain and will contain the necessary logic
//                              to call / process the extension for the appropriate
//                              ICDs that are available.
// There is no generic mechanism for including these functions, the references
// must be placed into the appropriate loader entry points.
// GetInstanceProcAddr: call extension GetInstanceProcAddr to check for GetProcAddr
// requests
// loader_coalesce_extensions(void) - add extension records to the list of global
//                                    extension available to the app.
// instance_disp                    - add function pointer for terminator function
//                                    to this array.
// The extension itself should be in a separate file that will be linked directly
// with the loader.
VkResult loader_get_icd_loader_instance_extensions(const struct loader_instance *inst, struct loader_icd_tramp_list *icd_tramp_list,
                                                   struct loader_extension_list *inst_exts) {
    struct loader_extension_list icd_exts;
    VkResult res = VK_SUCCESS;
    char *env_value;
    bool filter_extensions = true;

    // Check if a user wants to disable the instance extension filtering behavior
    env_value = loader_getenv("VK_LOADER_DISABLE_INST_EXT_FILTER", inst);
    if (NULL != env_value && atoi(env_value) != 0) {
        filter_extensions = false;
    }
    loader_free_getenv(env_value, inst);

    // traverse scanned icd list adding non-duplicate extensions to the list
    for (uint32_t i = 0; i < icd_tramp_list->count; i++) {
        res = loader_init_generic_list(inst, (struct loader_generic_list *)&icd_exts, sizeof(VkExtensionProperties));
        if (VK_SUCCESS != res) {
            goto out;
        }
        res = loader_add_instance_extensions(inst, icd_tramp_list->scanned_list[i].EnumerateInstanceExtensionProperties,
                                             icd_tramp_list->scanned_list[i].lib_name, &icd_exts);
        if (VK_SUCCESS == res) {
            if (filter_extensions) {
                // Remove any extensions not recognized by the loader
                for (int32_t j = 0; j < (int32_t)icd_exts.count; j++) {
                    // See if the extension is in the list of supported extensions
                    bool found = false;
                    for (uint32_t k = 0; LOADER_INSTANCE_EXTENSIONS[k] != NULL; k++) {
                        if (strcmp(icd_exts.list[j].extensionName, LOADER_INSTANCE_EXTENSIONS[k]) == 0) {
                            found = true;
                            break;
                        }
                    }

                    // If it isn't in the list, remove it
                    if (!found) {
                        for (uint32_t k = j + 1; k < icd_exts.count; k++) {
                            icd_exts.list[k - 1] = icd_exts.list[k];
                        }
                        --icd_exts.count;
                        --j;
                    }
                }
            }

            res = loader_add_to_ext_list(inst, inst_exts, icd_exts.count, icd_exts.list);
        }
        loader_destroy_generic_list(inst, (struct loader_generic_list *)&icd_exts);
        if (VK_SUCCESS != res) {
            goto out;
        }
    };

    // Traverse loader's extensions, adding non-duplicate extensions to the list
    add_debug_extensions_to_ext_list(inst, inst_exts);

    static const VkExtensionProperties portability_enumeration_extension_info[] = {
        {VK_KHR_PORTABILITY_ENUMERATION_EXTENSION_NAME, VK_KHR_PORTABILITY_ENUMERATION_SPEC_VERSION}};

    // Add VK_KHR_portability_subset
    loader_add_to_ext_list(inst, inst_exts, sizeof(portability_enumeration_extension_info) / sizeof(VkExtensionProperties),
                           portability_enumeration_extension_info);

    static const VkExtensionProperties direct_driver_loading_extension_info[] = {
        {VK_LUNARG_DIRECT_DRIVER_LOADING_EXTENSION_NAME, VK_LUNARG_DIRECT_DRIVER_LOADING_SPEC_VERSION}};

    // Add VK_LUNARG_direct_driver_loading
    loader_add_to_ext_list(inst, inst_exts, sizeof(direct_driver_loading_extension_info) / sizeof(VkExtensionProperties),
                           direct_driver_loading_extension_info);
out:
    return res;
}

struct loader_icd_term *loader_get_icd_and_device(const void *device, struct loader_device **found_dev, uint32_t *icd_index) {
    loader_platform_thread_lock_mutex(&loader_global_instance_list_lock);
    *found_dev = NULL;
    for (struct loader_instance *inst = loader.instances; inst; inst = inst->next) {
        uint32_t index = 0;
        for (struct loader_icd_term *icd_term = inst->icd_terms; icd_term; icd_term = icd_term->next) {
            for (struct loader_device *dev = icd_term->logical_device_list; dev; dev = dev->next)
                // Value comparison of device prevents object wrapping by layers
                if (loader_get_dispatch(dev->icd_device) == loader_get_dispatch(device) ||
                    (dev->chain_device != VK_NULL_HANDLE &&
                     loader_get_dispatch(dev->chain_device) == loader_get_dispatch(device))) {
                    *found_dev = dev;
                    if (NULL != icd_index) {
                        *icd_index = index;
                    }
                    loader_platform_thread_unlock_mutex(&loader_global_instance_list_lock);
                    return icd_term;
                }
            index++;
        }
    }
    loader_platform_thread_unlock_mutex(&loader_global_instance_list_lock);
    return NULL;
}

void loader_destroy_logical_device(const struct loader_instance *inst, struct loader_device *dev,
                                   const VkAllocationCallbacks *pAllocator) {
    if (pAllocator) {
        dev->alloc_callbacks = *pAllocator;
    }
    loader_destroy_layer_list(inst, dev, &dev->expanded_activated_layer_list);
    loader_destroy_layer_list(inst, dev, &dev->app_activated_layer_list);
    loader_device_heap_free(dev, dev);
}

struct loader_device *loader_create_logical_device(const struct loader_instance *inst, const VkAllocationCallbacks *pAllocator) {
    struct loader_device *new_dev;
    new_dev = loader_calloc(pAllocator, sizeof(struct loader_device), VK_SYSTEM_ALLOCATION_SCOPE_DEVICE);

    if (!new_dev) {
        loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0, "loader_create_logical_device: Failed to alloc struct loader_device");
        return NULL;
    }

    if (pAllocator) {
        new_dev->alloc_callbacks = *pAllocator;
    }

    return new_dev;
}

void loader_add_logical_device(const struct loader_instance *inst, struct loader_icd_term *icd_term, struct loader_device *dev) {
    dev->next = icd_term->logical_device_list;
    icd_term->logical_device_list = dev;
}

void loader_remove_logical_device(const struct loader_instance *inst, struct loader_icd_term *icd_term,
                                  struct loader_device *found_dev, const VkAllocationCallbacks *pAllocator) {
    struct loader_device *dev, *prev_dev;

    if (!icd_term || !found_dev) return;

    prev_dev = NULL;
    dev = icd_term->logical_device_list;
    while (dev && dev != found_dev) {
        prev_dev = dev;
        dev = dev->next;
    }

    if (prev_dev)
        prev_dev->next = found_dev->next;
    else
        icd_term->logical_device_list = found_dev->next;
    loader_destroy_logical_device(inst, found_dev, pAllocator);
}

void loader_icd_destroy(struct loader_instance *ptr_inst, struct loader_icd_term *icd_term,
                        const VkAllocationCallbacks *pAllocator) {
    ptr_inst->total_icd_count--;
    for (struct loader_device *dev = icd_term->logical_device_list; dev;) {
        struct loader_device *next_dev = dev->next;
        loader_destroy_logical_device(ptr_inst, dev, pAllocator);
        dev = next_dev;
    }

    loader_instance_heap_free(ptr_inst, icd_term);
}

static struct loader_icd_term *loader_icd_add(struct loader_instance *ptr_inst, const struct loader_scanned_icd *scanned_icd) {
    struct loader_icd_term *icd_term;

    icd_term = loader_instance_heap_calloc(ptr_inst, sizeof(struct loader_icd_term), VK_SYSTEM_ALLOCATION_SCOPE_INSTANCE);
    if (!icd_term) {
        return NULL;
    }

    icd_term->scanned_icd = scanned_icd;
    icd_term->this_instance = ptr_inst;

    // Prepend to the list
    icd_term->next = ptr_inst->icd_terms;
    ptr_inst->icd_terms = icd_term;
    ptr_inst->total_icd_count++;

    return icd_term;
}

// Determine the ICD interface version to use.
//     @param icd
//     @param pVersion Output parameter indicating which version to use or 0 if
//            the negotiation API is not supported by the ICD
//     @return  bool indicating true if the selected interface version is supported
//            by the loader, false indicates the version is not supported
bool loader_get_icd_interface_version(PFN_vkNegotiateLoaderICDInterfaceVersion fp_negotiate_icd_version, uint32_t *pVersion) {
    if (fp_negotiate_icd_version == NULL) {
        // ICD does not support the negotiation API, it supports version 0 or 1
        // calling code must determine if it is version 0 or 1
        *pVersion = 0;
    } else {
        // ICD supports the negotiation API, so call it with the loader's
        // latest version supported
        *pVersion = CURRENT_LOADER_ICD_INTERFACE_VERSION;
        VkResult result = fp_negotiate_icd_version(pVersion);

        if (result == VK_ERROR_INCOMPATIBLE_DRIVER) {
            // ICD no longer supports the loader's latest interface version so
            // fail loading the ICD
            return false;
        }
    }

#if MIN_SUPPORTED_LOADER_ICD_INTERFACE_VERSION > 0
    if (*pVersion < MIN_SUPPORTED_LOADER_ICD_INTERFACE_VERSION) {
        // Loader no longer supports the ICD's latest interface version so fail
        // loading the ICD
        return false;
    }
#endif
    return true;
}

void loader_scanned_icd_clear(const struct loader_instance *inst, struct loader_icd_tramp_list *icd_tramp_list) {
    if (0 != icd_tramp_list->capacity) {
        for (uint32_t i = 0; i < icd_tramp_list->count; i++) {
            if (icd_tramp_list->scanned_list[i].handle) {
                loader_platform_close_library(icd_tramp_list->scanned_list[i].handle);
                icd_tramp_list->scanned_list[i].handle = NULL;
            }
            loader_instance_heap_free(inst, icd_tramp_list->scanned_list[i].lib_name);
        }
        loader_instance_heap_free(inst, icd_tramp_list->scanned_list);
    }
    icd_tramp_list->capacity = 0;
    icd_tramp_list->count = 0;
    icd_tramp_list->scanned_list = NULL;
}

VkResult loader_scanned_icd_init(const struct loader_instance *inst, struct loader_icd_tramp_list *icd_tramp_list) {
    VkResult res = VK_SUCCESS;
    loader_scanned_icd_clear(inst, icd_tramp_list);
    icd_tramp_list->capacity = 8 * sizeof(struct loader_scanned_icd);
    icd_tramp_list->scanned_list = loader_instance_heap_alloc(inst, icd_tramp_list->capacity, VK_SYSTEM_ALLOCATION_SCOPE_INSTANCE);
    if (NULL == icd_tramp_list->scanned_list) {
        loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                   "loader_scanned_icd_init: Realloc failed for layer list when attempting to add new layer");
        res = VK_ERROR_OUT_OF_HOST_MEMORY;
    }
    return res;
}

VkResult loader_add_direct_driver(const struct loader_instance *inst, uint32_t index,
                                  const VkDirectDriverLoadingInfoLUNARG *pDriver, struct loader_icd_tramp_list *icd_tramp_list) {
    // Assume pDriver is valid, since there is no real way to check it. Calling code should make sure the pointer to the array of
    // VkDirectDriverLoadingInfoLUNARG structures is non-null.
    if (NULL == pDriver->pfnGetInstanceProcAddr) {
        loader_log(
            inst, VULKAN_LOADER_ERROR_BIT | VULKAN_LOADER_DRIVER_BIT, 0,
            "loader_add_direct_driver: VkDirectDriverLoadingInfoLUNARG structure at index %d contains a NULL pointer for the "
            "pfnGetInstanceProcAddr member, skipping.",
            index);
        return VK_ERROR_INITIALIZATION_FAILED;
    }

    PFN_vkGetInstanceProcAddr fp_get_proc_addr = pDriver->pfnGetInstanceProcAddr;
    PFN_vkCreateInstance fp_create_inst = NULL;
    PFN_vkEnumerateInstanceExtensionProperties fp_get_inst_ext_props = NULL;
    PFN_GetPhysicalDeviceProcAddr fp_get_phys_dev_proc_addr = NULL;
    PFN_vkNegotiateLoaderICDInterfaceVersion fp_negotiate_icd_version = NULL;
#if defined(VK_USE_PLATFORM_WIN32_KHR)
    PFN_vk_icdEnumerateAdapterPhysicalDevices fp_enum_dxgi_adapter_phys_devs = NULL;
#endif
    struct loader_scanned_icd *new_scanned_icd;
    uint32_t interface_version = 0;

    // Try to get the negotiate ICD interface version function
    fp_negotiate_icd_version = (PFN_vk_icdNegotiateLoaderICDInterfaceVersion)pDriver->pfnGetInstanceProcAddr(
        NULL, "vk_icdNegotiateLoaderICDInterfaceVersion");

    if (NULL == fp_negotiate_icd_version) {
        loader_log(inst, VULKAN_LOADER_ERROR_BIT | VULKAN_LOADER_DRIVER_BIT, 0,
                   "loader_add_direct_driver: Could not get 'vk_icdNegotiateLoaderICDInterfaceVersion' from "
                   "VkDirectDriverLoadingInfoLUNARG structure at "
                   "index %d, skipping.",
                   index);
        return VK_ERROR_INITIALIZATION_FAILED;
    }

    if (!loader_get_icd_interface_version(fp_negotiate_icd_version, &interface_version)) {
        loader_log(
            inst, VULKAN_LOADER_ERROR_BIT | VULKAN_LOADER_DRIVER_BIT, 0,
            "loader_add_direct_driver: VkDirectDriverLoadingInfoLUNARG structure at index %d supports interface version %d, "
            "which is incompatible with the Loader Driver Interface version that supports the VK_LUNARG_direct_driver_loading "
            "extension, skipping.",
            index, interface_version);
        return VK_ERROR_INITIALIZATION_FAILED;
    }

    if (interface_version < 7) {
        loader_log(
            inst, VULKAN_LOADER_ERROR_BIT | VULKAN_LOADER_DRIVER_BIT, 0,
            "loader_add_direct_driver: VkDirectDriverLoadingInfoLUNARG structure at index %d supports interface version %d, "
            "which is incompatible with the Loader Driver Interface version that supports the VK_LUNARG_direct_driver_loading "
            "extension, skipping.",
            index, interface_version);
        return VK_ERROR_INITIALIZATION_FAILED;
    }

    fp_create_inst = (PFN_vkCreateInstance)pDriver->pfnGetInstanceProcAddr(NULL, "vkCreateInstance");
    if (NULL == fp_create_inst) {
        loader_log(inst, VULKAN_LOADER_ERROR_BIT | VULKAN_LOADER_DRIVER_BIT, 0,
                   "loader_add_direct_driver: Could not get 'vkCreateInstance' from VkDirectDriverLoadingInfoLUNARG structure at "
                   "index %d, skipping.",
                   index);
        return VK_ERROR_INITIALIZATION_FAILED;
    }
    fp_get_inst_ext_props =
        (PFN_vkEnumerateInstanceExtensionProperties)pDriver->pfnGetInstanceProcAddr(NULL, "vkEnumerateInstanceExtensionProperties");
    if (NULL == fp_get_inst_ext_props) {
        loader_log(inst, VULKAN_LOADER_ERROR_BIT | VULKAN_LOADER_DRIVER_BIT, 0,
                   "loader_add_direct_driver: Could not get 'vkEnumerateInstanceExtensionProperties' from "
                   "VkDirectDriverLoadingInfoLUNARG structure at index %d, skipping.",
                   index);
        return VK_ERROR_INITIALIZATION_FAILED;
    }

    fp_get_phys_dev_proc_addr =
        (PFN_vk_icdGetPhysicalDeviceProcAddr)pDriver->pfnGetInstanceProcAddr(NULL, "vk_icdGetPhysicalDeviceProcAddr");
#if defined(VK_USE_PLATFORM_WIN32_KHR)
    // Query "vk_icdEnumerateAdapterPhysicalDevices" with vk_icdGetInstanceProcAddr if the library reports interface version
    // 7 or greater, otherwise fallback to loading it from the platform dynamic linker
    fp_enum_dxgi_adapter_phys_devs =
        (PFN_vk_icdEnumerateAdapterPhysicalDevices)pDriver->pfnGetInstanceProcAddr(NULL, "vk_icdEnumerateAdapterPhysicalDevices");
#endif

    // check for enough capacity
    if ((icd_tramp_list->count * sizeof(struct loader_scanned_icd)) >= icd_tramp_list->capacity) {
        void *new_ptr = loader_instance_heap_realloc(inst, icd_tramp_list->scanned_list, icd_tramp_list->capacity,
                                                     icd_tramp_list->capacity * 2, VK_SYSTEM_ALLOCATION_SCOPE_INSTANCE);
        if (NULL == new_ptr) {
            loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0, "loader_add_direct_driver: Realloc failed on icd library list for ICD %s");
            return VK_ERROR_OUT_OF_HOST_MEMORY;
        }
        icd_tramp_list->scanned_list = new_ptr;

        // double capacity
        icd_tramp_list->capacity *= 2;
    }

    // Driver must be 1.1 to support version 7
    uint32_t api_version = VK_API_VERSION_1_1;
    PFN_vkEnumerateInstanceVersion icd_enumerate_instance_version =
        (PFN_vkEnumerateInstanceVersion)pDriver->pfnGetInstanceProcAddr(NULL, "vkEnumerateInstanceVersion");

    if (icd_enumerate_instance_version) {
        VkResult res = icd_enumerate_instance_version(&api_version);
        if (res != VK_SUCCESS) {
            return res;
        }
    }

    new_scanned_icd = &(icd_tramp_list->scanned_list[icd_tramp_list->count]);
    new_scanned_icd->handle = NULL;
    new_scanned_icd->api_version = api_version;
    new_scanned_icd->GetInstanceProcAddr = fp_get_proc_addr;
    new_scanned_icd->GetPhysicalDeviceProcAddr = fp_get_phys_dev_proc_addr;
    new_scanned_icd->EnumerateInstanceExtensionProperties = fp_get_inst_ext_props;
    new_scanned_icd->CreateInstance = fp_create_inst;
#if defined(VK_USE_PLATFORM_WIN32_KHR)
    new_scanned_icd->EnumerateAdapterPhysicalDevices = fp_enum_dxgi_adapter_phys_devs;
#endif
    new_scanned_icd->interface_version = interface_version;

    new_scanned_icd->lib_name = NULL;
    icd_tramp_list->count++;

    loader_log(inst, VULKAN_LOADER_INFO_BIT | VULKAN_LOADER_DRIVER_BIT, 0,
               "loader_add_direct_driver: Adding driver found in index %d of "
               "VkDirectDriverLoadingListLUNARG::pDrivers structure. pfnGetInstanceProcAddr was set to %p",
               index, pDriver->pfnGetInstanceProcAddr);

    return VK_SUCCESS;
}

// Search through VkInstanceCreateInfo's pNext chain for any drivers from the direct driver loading extension and load them.
VkResult loader_scan_for_direct_drivers(const struct loader_instance *inst, const VkInstanceCreateInfo *pCreateInfo,
                                        struct loader_icd_tramp_list *icd_tramp_list, bool *direct_driver_loading_exclusive_mode) {
    if (NULL == pCreateInfo) {
        // Don't do this logic unless we are being called from vkCreateInstance, when pCreateInfo will be non-null
        return VK_SUCCESS;
    }
    bool direct_driver_loading_enabled = false;
    // Try to if VK_LUNARG_direct_driver_loading is enabled and if we are using it exclusively
    // Skip this step if inst is NULL, aka when this function is being called before instance creation
    if (inst != NULL && pCreateInfo->ppEnabledExtensionNames && pCreateInfo->enabledExtensionCount > 0) {
        // Look through the enabled extension list, make sure VK_LUNARG_direct_driver_loading is present
        for (uint32_t i = 0; i < pCreateInfo->enabledExtensionCount; i++) {
            if (strcmp(pCreateInfo->ppEnabledExtensionNames[i], VK_LUNARG_DIRECT_DRIVER_LOADING_EXTENSION_NAME) == 0) {
                direct_driver_loading_enabled = true;
                break;
            }
        }
    }
    const VkDirectDriverLoadingListLUNARG *ddl_list = NULL;
    // Find the VkDirectDriverLoadingListLUNARG struct in the pNext chain of vkInstanceCreateInfo
    const VkBaseOutStructure *chain = pCreateInfo->pNext;
    while (chain) {
        if (chain->sType == VK_STRUCTURE_TYPE_DIRECT_DRIVER_LOADING_LIST_LUNARG) {
            ddl_list = (VkDirectDriverLoadingListLUNARG *)chain;
            break;
        }
        chain = (const VkBaseOutStructure *)chain->pNext;
    }
    if (NULL == ddl_list) {
        if (direct_driver_loading_enabled) {
            loader_log(
                inst, VULKAN_LOADER_WARN_BIT | VULKAN_LOADER_DRIVER_BIT, 0,
                "loader_scan_for_direct_drivers: The VK_LUNARG_direct_driver_loading extension was enabled but the pNext chain of "
                "VkInstanceCreateInfo did not contain the "
                "VkDirectDriverLoadingListLUNARG structure.");
        }
        // Always want to exit early if there was no VkDirectDriverLoadingListLUNARG in the pNext chain
        return VK_SUCCESS;
    }

    if (!direct_driver_loading_enabled) {
        loader_log(inst, VULKAN_LOADER_WARN_BIT | VULKAN_LOADER_DRIVER_BIT, 0,
                   "loader_scan_for_direct_drivers: The pNext chain of VkInstanceCreateInfo contained the "
                   "VkDirectDriverLoadingListLUNARG structure, but the VK_LUNARG_direct_driver_loading extension was "
                   "not enabled.");
        return VK_SUCCESS;
    }
    // If we are using exclusive mode, skip looking for any more drivers from system or environment variables
    if (ddl_list->mode == VK_DIRECT_DRIVER_LOADING_MODE_EXCLUSIVE_LUNARG) {
        *direct_driver_loading_exclusive_mode = true;
        loader_log(inst, VULKAN_LOADER_INFO_BIT | VULKAN_LOADER_DRIVER_BIT, 0,
                   "loader_scan_for_direct_drivers: The VK_LUNARG_direct_driver_loading extension is active and specified "
                   "VK_DIRECT_DRIVER_LOADING_MODE_EXCLUSIVE_LUNARG, skipping system and environment "
                   "variable driver search mechanisms.");
    }
    if (NULL == ddl_list->pDrivers) {
        loader_log(inst, VULKAN_LOADER_WARN_BIT | VULKAN_LOADER_DRIVER_BIT, 0,
                   "loader_scan_for_direct_drivers: The VkDirectDriverLoadingListLUNARG structure in the pNext chain of "
                   "VkInstanceCreateInfo has a NULL pDrivers member.");
        return VK_SUCCESS;
    }
    if (ddl_list->driverCount == 0) {
        loader_log(inst, VULKAN_LOADER_WARN_BIT | VULKAN_LOADER_DRIVER_BIT, 0,
                   "loader_scan_for_direct_drivers: The VkDirectDriverLoadingListLUNARG structure in the pNext chain of "
                   "VkInstanceCreateInfo has a non-null pDrivers member but a driverCount member with a value "
                   "of zero.");
        return VK_SUCCESS;
    }
    // Go through all VkDirectDriverLoadingInfoLUNARG entries and add each driver
    // Because icd_tramp's are prepended, this will result in the drivers appearing at the end
    for (uint32_t i = 0; i < ddl_list->driverCount; i++) {
        VkResult res = loader_add_direct_driver(inst, i, &ddl_list->pDrivers[i], icd_tramp_list);
        if (res == VK_ERROR_OUT_OF_HOST_MEMORY) {
            return res;
        }
    }

    return VK_SUCCESS;
}

static VkResult loader_scanned_icd_add(const struct loader_instance *inst, struct loader_icd_tramp_list *icd_tramp_list,
                                       const char *filename, uint32_t api_version, enum loader_layer_library_status *lib_status) {
    loader_platform_dl_handle handle = NULL;
    PFN_vkCreateInstance fp_create_inst = NULL;
    PFN_vkEnumerateInstanceExtensionProperties fp_get_inst_ext_props = NULL;
    PFN_vkGetInstanceProcAddr fp_get_proc_addr = NULL;
    PFN_GetPhysicalDeviceProcAddr fp_get_phys_dev_proc_addr = NULL;
    PFN_vkNegotiateLoaderICDInterfaceVersion fp_negotiate_icd_version = NULL;
#if defined(VK_USE_PLATFORM_WIN32_KHR)
    PFN_vk_icdEnumerateAdapterPhysicalDevices fp_enum_dxgi_adapter_phys_devs = NULL;
#endif
    struct loader_scanned_icd *new_scanned_icd;
    uint32_t interface_vers;
    VkResult res = VK_SUCCESS;

    // This shouldn't happen, but the check is necessary because dlopen returns a handle to the main program when
    // filename is NULL
    if (filename == NULL) {
        loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0, "loader_scanned_icd_add: A NULL filename was used, skipping this ICD",
                   filename);
        res = VK_ERROR_INCOMPATIBLE_DRIVER;
        goto out;
    }

    // TODO implement smarter opening/closing of libraries. For now this
    // function leaves libraries open and the scanned_icd_clear closes them
#if defined(__Fuchsia__)
    handle = loader_platform_open_driver(filename);
#else
    handle = loader_platform_open_library(filename);
#endif
    if (NULL == handle) {
        loader_handle_load_library_error(inst, filename, lib_status);
        if (lib_status && *lib_status == LOADER_LAYER_LIB_ERROR_OUT_OF_MEMORY) {
            res = VK_ERROR_OUT_OF_HOST_MEMORY;
        } else {
            res = VK_ERROR_INCOMPATIBLE_DRIVER;
        }
        goto out;
    }

    // Try to load the driver's exported vk_icdNegotiateLoaderICDInterfaceVersion
    fp_negotiate_icd_version = loader_platform_get_proc_address(handle, "vk_icdNegotiateLoaderICDInterfaceVersion");

    // If it isn't exported, we are dealing with either a v0, v1, or a v7 and up driver
    if (NULL == fp_negotiate_icd_version) {
        // Try to load the driver's exported vk_icdGetInstanceProcAddr - if this is a v7 or up driver, we can use it to get
        // the driver's vk_icdNegotiateLoaderICDInterfaceVersion function
        fp_get_proc_addr = loader_platform_get_proc_address(handle, "vk_icdGetInstanceProcAddr");

        // If we successfully loaded vk_icdGetInstanceProcAddr, try to get vk_icdNegotiateLoaderICDInterfaceVersion
        if (fp_get_proc_addr) {
            fp_negotiate_icd_version =
                (PFN_vk_icdNegotiateLoaderICDInterfaceVersion)fp_get_proc_addr(NULL, "vk_icdNegotiateLoaderICDInterfaceVersion");
        }
    }

    // Try to negotiate the Loader and Driver Interface Versions
    // loader_get_icd_interface_version will check if fp_negotiate_icd_version is NULL, so we don't have to.
    // If it *is* NULL, that means this driver uses interface version 0 or 1
    if (!loader_get_icd_interface_version(fp_negotiate_icd_version, &interface_vers)) {
        loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                   "loader_scanned_icd_add: ICD %s doesn't support interface version compatible with loader, skip this ICD.",
                   filename);
        goto out;
    }

    // If we didn't already query vk_icdGetInstanceProcAddr, try now
    if (NULL == fp_get_proc_addr) {
        fp_get_proc_addr = loader_platform_get_proc_address(handle, "vk_icdGetInstanceProcAddr");
    }

    // If vk_icdGetInstanceProcAddr is NULL, this ICD is using version 0 and so we should respond accordingly.
    if (NULL == fp_get_proc_addr) {
        // Exporting vk_icdNegotiateLoaderICDInterfaceVersion but not vk_icdGetInstanceProcAddr violates Version 2's requirements,
        // as for Version 2 to be supported Version 1 must also be supported
        if (interface_vers != 0) {
            loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                       "loader_scanned_icd_add: ICD %s reports an interface version of %d but doesn't export "
                       "vk_icdGetInstanceProcAddr, skip this ICD.",
                       filename, interface_vers);
            goto out;
        }
        // Use deprecated interface from version 0
        fp_get_proc_addr = loader_platform_get_proc_address(handle, "vkGetInstanceProcAddr");
        if (NULL == fp_get_proc_addr) {
            loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                       "loader_scanned_icd_add: Attempt to retrieve either \'vkGetInstanceProcAddr\' or "
                       "\'vk_icdGetInstanceProcAddr\' from ICD %s failed.",
                       filename);
            goto out;
        } else {
            loader_log(inst, VULKAN_LOADER_WARN_BIT, 0,
                       "loader_scanned_icd_add: Using deprecated ICD interface of \'vkGetInstanceProcAddr\' instead of "
                       "\'vk_icdGetInstanceProcAddr\' for ICD %s",
                       filename);
        }
        fp_create_inst = loader_platform_get_proc_address(handle, "vkCreateInstance");
        if (NULL == fp_create_inst) {
            loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                       "loader_scanned_icd_add:  Failed querying \'vkCreateInstance\' via dlsym/loadlibrary for ICD %s", filename);
            goto out;
        }
        fp_get_inst_ext_props = loader_platform_get_proc_address(handle, "vkEnumerateInstanceExtensionProperties");
        if (NULL == fp_get_inst_ext_props) {
            loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                       "loader_scanned_icd_add: Could not get \'vkEnumerateInstanceExtensionProperties\' via dlsym/loadlibrary "
                       "for ICD %s",
                       filename);
            goto out;
        }
    } else {
        // vk_icdGetInstanceProcAddr was successfully found, we can assume the version is at least one
        // If vk_icdNegotiateLoaderICDInterfaceVersion was also found, interface_vers must be 2 or greater, so this check is fine
        if (interface_vers == 0) {
            interface_vers = 1;
        }

        fp_create_inst = (PFN_vkCreateInstance)fp_get_proc_addr(NULL, "vkCreateInstance");
        if (NULL == fp_create_inst) {
            loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                       "loader_scanned_icd_add: Could not get \'vkCreateInstance\' via \'vk_icdGetInstanceProcAddr\' for ICD %s",
                       filename);
            goto out;
        }
        fp_get_inst_ext_props =
            (PFN_vkEnumerateInstanceExtensionProperties)fp_get_proc_addr(NULL, "vkEnumerateInstanceExtensionProperties");
        if (NULL == fp_get_inst_ext_props) {
            loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                       "loader_scanned_icd_add: Could not get \'vkEnumerateInstanceExtensionProperties\' via "
                       "\'vk_icdGetInstanceProcAddr\' for ICD %s",
                       filename);
            goto out;
        }
        // Query "vk_icdGetPhysicalDeviceProcAddr" with vk_icdGetInstanceProcAddr if the library reports interface version 7 or
        // greater, otherwise fallback to loading it from the platform dynamic linker
        if (interface_vers >= 7) {
            fp_get_phys_dev_proc_addr =
                (PFN_vk_icdGetPhysicalDeviceProcAddr)fp_get_proc_addr(NULL, "vk_icdGetPhysicalDeviceProcAddr");
        }
        if (NULL == fp_get_phys_dev_proc_addr && interface_vers >= 3) {
            fp_get_phys_dev_proc_addr = loader_platform_get_proc_address(handle, "vk_icdGetPhysicalDeviceProcAddr");
        }
#if defined(VK_USE_PLATFORM_WIN32_KHR)
        // Query "vk_icdEnumerateAdapterPhysicalDevices" with vk_icdGetInstanceProcAddr if the library reports interface version 7
        // or greater, otherwise fallback to loading it from the platform dynamic linker
        if (interface_vers >= 7) {
            fp_enum_dxgi_adapter_phys_devs =
                (PFN_vk_icdEnumerateAdapterPhysicalDevices)fp_get_proc_addr(NULL, "vk_icdEnumerateAdapterPhysicalDevices");
        }
        if (NULL == fp_enum_dxgi_adapter_phys_devs && interface_vers >= 6) {
            fp_enum_dxgi_adapter_phys_devs = loader_platform_get_proc_address(handle, "vk_icdEnumerateAdapterPhysicalDevices");
        }
#endif
    }

    // check for enough capacity
    if ((icd_tramp_list->count * sizeof(struct loader_scanned_icd)) >= icd_tramp_list->capacity) {
        void *new_ptr = loader_instance_heap_realloc(inst, icd_tramp_list->scanned_list, icd_tramp_list->capacity,
                                                     icd_tramp_list->capacity * 2, VK_SYSTEM_ALLOCATION_SCOPE_INSTANCE);
        if (NULL == new_ptr) {
            res = VK_ERROR_OUT_OF_HOST_MEMORY;
            loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0, "loader_scanned_icd_add: Realloc failed on icd library list for ICD %s",
                       filename);
            goto out;
        }
        icd_tramp_list->scanned_list = new_ptr;

        // double capacity
        icd_tramp_list->capacity *= 2;
    }

    loader_api_version api_version_struct = loader_make_version(api_version);
    if (interface_vers <= 4 && loader_check_version_meets_required(LOADER_VERSION_1_1_0, api_version_struct)) {
        loader_log(inst, VULKAN_LOADER_WARN_BIT, 0,
                   "loader_scanned_icd_add: Driver %s supports Vulkan %u.%u, but only supports loader interface version %u."
                   " Interface version 5 or newer required to support this version of Vulkan (Policy #LDP_DRIVER_7)",
                   filename, api_version_struct.major, api_version_struct.minor, interface_vers);
    }

    new_scanned_icd = &(icd_tramp_list->scanned_list[icd_tramp_list->count]);
    new_scanned_icd->handle = handle;
    new_scanned_icd->api_version = api_version;
    new_scanned_icd->GetInstanceProcAddr = fp_get_proc_addr;
    new_scanned_icd->GetPhysicalDeviceProcAddr = fp_get_phys_dev_proc_addr;
    new_scanned_icd->EnumerateInstanceExtensionProperties = fp_get_inst_ext_props;
    new_scanned_icd->CreateInstance = fp_create_inst;
#if defined(VK_USE_PLATFORM_WIN32_KHR)
    new_scanned_icd->EnumerateAdapterPhysicalDevices = fp_enum_dxgi_adapter_phys_devs;
#endif
    new_scanned_icd->interface_version = interface_vers;

    new_scanned_icd->lib_name = (char *)loader_instance_heap_alloc(inst, strlen(filename) + 1, VK_SYSTEM_ALLOCATION_SCOPE_INSTANCE);
    if (NULL == new_scanned_icd->lib_name) {
        loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0, "loader_scanned_icd_add: Out of memory can't add ICD %s", filename);
        res = VK_ERROR_OUT_OF_HOST_MEMORY;
        goto out;
    }
    strcpy(new_scanned_icd->lib_name, filename);
    icd_tramp_list->count++;

out:

    return res;
}

void loader_initialize(void) {
    // initialize mutexes
    loader_platform_thread_create_mutex(&loader_lock);
    loader_platform_thread_create_mutex(&loader_json_lock);
    loader_platform_thread_create_mutex(&loader_preload_icd_lock);
    loader_platform_thread_create_mutex(&loader_global_instance_list_lock);

    // initialize logging
    loader_debug_init();
#if defined(_WIN32)
    windows_initialization();
#endif

    loader_api_version version = loader_make_full_version(VK_HEADER_VERSION_COMPLETE);
    loader_log(NULL, VULKAN_LOADER_INFO_BIT, 0, "Vulkan Loader Version %d.%d.%d", version.major, version.minor, version.patch);

#if defined(GIT_BRANCH_NAME) && defined(GIT_TAG_INFO)
    loader_log(NULL, VULKAN_LOADER_INFO_BIT, 0, "[Vulkan Loader Git - Tag: " GIT_BRANCH_NAME ", Branch/Commit: " GIT_TAG_INFO "]");
#endif
}

void loader_release() {
    // Guarantee release of the preloaded ICD libraries. This may have already been called in vkDestroyInstance.
    loader_unload_preloaded_icds();

    // release mutexes
    loader_platform_thread_delete_mutex(&loader_lock);
    loader_platform_thread_delete_mutex(&loader_json_lock);
    loader_platform_thread_delete_mutex(&loader_preload_icd_lock);
    loader_platform_thread_delete_mutex(&loader_global_instance_list_lock);
}

// Preload the ICD libraries that are likely to be needed so we don't repeatedly load/unload them later
void loader_preload_icds(void) {
    loader_platform_thread_lock_mutex(&loader_preload_icd_lock);

    // Already preloaded, skip loading again.
    if (scanned_icds.scanned_list != NULL) {
        loader_platform_thread_unlock_mutex(&loader_preload_icd_lock);
        return;
    }

    VkResult result = loader_icd_scan(NULL, &scanned_icds, NULL, NULL);
    if (result != VK_SUCCESS) {
        loader_scanned_icd_clear(NULL, &scanned_icds);
    }
    loader_platform_thread_unlock_mutex(&loader_preload_icd_lock);
}

// Release the ICD libraries that were preloaded
void loader_unload_preloaded_icds(void) {
    loader_platform_thread_lock_mutex(&loader_preload_icd_lock);
    loader_scanned_icd_clear(NULL, &scanned_icds);
    loader_platform_thread_unlock_mutex(&loader_preload_icd_lock);
}

#if !defined(_WIN32)
__attribute__((constructor)) void loader_init_library() { loader_initialize(); }

__attribute__((destructor)) void loader_free_library() { loader_release(); }
#endif

// Get next file or dirname given a string list or registry key path
//
// \returns
// A pointer to first char in the next path.
// The next path (or NULL) in the list is returned in next_path.
// Note: input string is modified in some cases. PASS IN A COPY!
char *loader_get_next_path(char *path) {
    uint32_t len;
    char *next;

    if (path == NULL) return NULL;
    next = strchr(path, PATH_SEPARATOR);
    if (next == NULL) {
        len = (uint32_t)strlen(path);
        next = path + len;
    } else {
        *next = '\0';
        next++;
    }

    return next;
}

// Given a path which is absolute or relative, expand the path if relative or
// leave the path unmodified if absolute. The base path to prepend to relative
// paths is given in rel_base.
//
// @return - A string in out_fullpath of the full absolute path
static void loader_expand_path(const char *path, const char *rel_base, size_t out_size, char *out_fullpath) {
    if (loader_platform_is_path_absolute(path)) {
        // do not prepend a base to an absolute path
        rel_base = "";
    }

    loader_platform_combine_path(out_fullpath, out_size, rel_base, path, NULL);
}

// Given a filename (file)  and a list of paths (dir), try to find an existing
// file in the paths.  If filename already is a path then no searching in the given paths.
//
// @return - A string in out_fullpath of either the full path or file.
static void loader_get_fullpath(const char *file, const char *in_dirs, size_t out_size, char *out_fullpath) {
    if (!loader_platform_is_path(file) && *in_dirs) {
        char *dirs_copy = loader_stack_alloc(strlen(in_dirs) + 1);
        strcpy(dirs_copy, in_dirs);

        // find if file exists after prepending paths in given list
        // for (dir = dirs_copy; *dir && (next_dir = loader_get_next_path(dir)); dir = next_dir) {
        char *dir = dirs_copy;
        char *next_dir = loader_get_next_path(dir);
        while (*dir && next_dir) {
            loader_platform_combine_path(out_fullpath, out_size, dir, file, NULL);
            if (loader_platform_file_exists(out_fullpath)) {
                return;
            }
            dir = next_dir;
            next_dir = loader_get_next_path(dir);
        }
    }

    (void)snprintf(out_fullpath, out_size, "%s", file);
}

// Read a JSON file into a buffer.
//
// @return -  A pointer to a cJSON object representing the JSON parse tree.
//            This returned buffer should be freed by caller.
static VkResult loader_get_json(const struct loader_instance *inst, const char *filename, cJSON **json) {
    FILE *file = NULL;
    char *json_buf = NULL;
    size_t len;
    VkResult res = VK_SUCCESS;

    assert(json != NULL);

    *json = NULL;

#if defined(_WIN32)
    int filename_utf16_size = MultiByteToWideChar(CP_UTF8, 0, filename, -1, NULL, 0);
    if (filename_utf16_size > 0) {
        wchar_t *filename_utf16 = (wchar_t *)loader_stack_alloc(filename_utf16_size * sizeof(wchar_t));
        if (MultiByteToWideChar(CP_UTF8, 0, filename, -1, filename_utf16, filename_utf16_size) == filename_utf16_size) {
            file = _wfopen(filename_utf16, L"rb");
        }
    }
#else
    file = fopen(filename, "rb");
#endif

    if (!file) {
        loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0, "loader_get_json: Failed to open JSON file %s", filename);
        res = VK_ERROR_INITIALIZATION_FAILED;
        goto out;
    }
    // NOTE: We can't just use fseek(file, 0, SEEK_END) because that isn't guaranteed to be supported on all systems
    size_t fread_ret_count = 0;
    do {
        char buffer[256];
        fread_ret_count = fread(buffer, 1, 256, file);
    } while (fread_ret_count == 256 && !feof(file));
    len = ftell(file);
    fseek(file, 0, SEEK_SET);
    json_buf = (char *)loader_instance_heap_alloc(inst, len + 1, VK_SYSTEM_ALLOCATION_SCOPE_COMMAND);
    if (json_buf == NULL) {
        loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                   "loader_get_json: Failed to allocate space for JSON file %s buffer of length %d", filename, len);
        res = VK_ERROR_OUT_OF_HOST_MEMORY;
        goto out;
    }
    if (fread(json_buf, sizeof(char), len, file) != len) {
        loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0, "loader_get_json: Failed to read JSON file %s.", filename);
        res = VK_ERROR_INITIALIZATION_FAILED;
        goto out;
    }
    json_buf[len] = '\0';

    // Can't be a valid json if the string is of length zero
    if (len == 0) {
        res = VK_ERROR_INITIALIZATION_FAILED;
        goto out;
    }
    // Parse text from file
    *json = cJSON_Parse(inst ? &inst->alloc_callbacks : NULL, json_buf);
    if (*json == NULL) {
        loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                   "loader_get_json: Failed to parse JSON file %s, this is usually because something ran out of memory.", filename);
        res = VK_ERROR_OUT_OF_HOST_MEMORY;
        goto out;
    }

out:
    loader_instance_heap_free(inst, json_buf);
    if (NULL != file) {
        fclose(file);
    }

    return res;
}

// Verify that all component layers in a meta-layer are valid.
static bool verify_meta_layer_component_layers(const struct loader_instance *inst, struct loader_layer_properties *prop,
                                               struct loader_layer_list *instance_layers) {
    bool success = true;
    loader_api_version meta_layer_version = loader_make_version(prop->info.specVersion);

    for (uint32_t comp_layer = 0; comp_layer < prop->num_component_layers; comp_layer++) {
        struct loader_layer_properties *comp_prop =
            loader_find_layer_property(prop->component_layer_names[comp_layer], instance_layers);
        if (comp_prop == NULL) {
            loader_log(inst, VULKAN_LOADER_WARN_BIT, 0,
                       "verify_meta_layer_component_layers: Meta-layer %s can't find component layer %s at index %d."
                       "  Skipping this layer.",
                       prop->info.layerName, prop->component_layer_names[comp_layer], comp_layer);

            success = false;
            break;
        }

        // Check the version of each layer, they need to be at least MAJOR and MINOR
        loader_api_version comp_prop_version = loader_make_version(comp_prop->info.specVersion);
        if (!loader_check_version_meets_required(meta_layer_version, comp_prop_version)) {
            loader_log(inst, VULKAN_LOADER_WARN_BIT, 0,
                       "verify_meta_layer_component_layers: Meta-layer uses API version %d.%d, but component "
                       "layer %d has API version %d.%d that is lower.  Skipping this layer.",
                       meta_layer_version.major, meta_layer_version.minor, comp_layer, comp_prop_version.major,
                       comp_prop_version.minor);

            success = false;
            break;
        }

        // Make sure the layer isn't using it's own name
        if (!strcmp(prop->info.layerName, prop->component_layer_names[comp_layer])) {
            loader_log(inst, VULKAN_LOADER_WARN_BIT, 0,
                       "verify_meta_layer_component_layers: Meta-layer %s lists itself in its component layer "
                       "list at index %d.  Skipping this layer.",
                       prop->info.layerName, comp_layer);

            success = false;
            break;
        }
        if (comp_prop->type_flags & VK_LAYER_TYPE_FLAG_META_LAYER) {
            loader_log(inst, VULKAN_LOADER_INFO_BIT, 0,
                       "verify_meta_layer_component_layers: Adding meta-layer %s which also contains meta-layer %s",
                       prop->info.layerName, comp_prop->info.layerName);

            // Make sure if the layer is using a meta-layer in its component list that we also verify that.
            if (!verify_meta_layer_component_layers(inst, comp_prop, instance_layers)) {
                loader_log(inst, VULKAN_LOADER_WARN_BIT, 0,
                           "Meta-layer %s component layer %s can not find all component layers."
                           "  Skipping this layer.",
                           prop->info.layerName, prop->component_layer_names[comp_layer]);
                success = false;
                break;
            }
        }

        // Add any instance and device extensions from component layers to this layer
        // list, so that anyone querying extensions will only need to look at the meta-layer
        for (uint32_t ext = 0; ext < comp_prop->instance_extension_list.count; ext++) {
            loader_log(inst, VULKAN_LOADER_DEBUG_BIT, 0, "Meta-layer %s component layer %s adding instance extension %s",
                       prop->info.layerName, prop->component_layer_names[comp_layer],
                       comp_prop->instance_extension_list.list[ext].extensionName);

            if (!has_vk_extension_property(&comp_prop->instance_extension_list.list[ext], &prop->instance_extension_list)) {
                loader_add_to_ext_list(inst, &prop->instance_extension_list, 1, &comp_prop->instance_extension_list.list[ext]);
            }
        }

        for (uint32_t ext = 0; ext < comp_prop->device_extension_list.count; ext++) {
            loader_log(inst, VULKAN_LOADER_DEBUG_BIT, 0, "Meta-layer %s component layer %s adding device extension %s",
                       prop->info.layerName, prop->component_layer_names[comp_layer],
                       comp_prop->device_extension_list.list[ext].props.extensionName);

            if (!has_vk_dev_ext_property(&comp_prop->device_extension_list.list[ext].props, &prop->device_extension_list)) {
                loader_add_to_dev_ext_list(inst, &prop->device_extension_list, &comp_prop->device_extension_list.list[ext].props, 0,
                                           NULL);
            }
        }
    }
    if (success) {
        loader_log(inst, VULKAN_LOADER_INFO_BIT | VULKAN_LOADER_LAYER_BIT, 0,
                   "Meta-layer \"%s\" all %d component layers appear to be valid.", prop->info.layerName,
                   prop->num_component_layers);

        // If layer logging is on, list the internals included in the meta-layer
        if ((loader_get_debug_level() & VULKAN_LOADER_LAYER_BIT) != 0) {
            for (uint32_t comp_layer = 0; comp_layer < prop->num_component_layers; comp_layer++) {
                loader_log(inst, VULKAN_LOADER_LAYER_BIT, 0, "  [%d] %s", comp_layer, prop->component_layer_names[comp_layer]);
            }
        }
    }
    return success;
}

// Verify that all meta-layers in a layer list are valid.
static void verify_all_meta_layers(struct loader_instance *inst, const struct loader_envvar_filter *enable_filter,
                                   const struct loader_envvar_disable_layers_filter *disable_filter,
                                   struct loader_layer_list *instance_layers, bool *override_layer_present) {
    *override_layer_present = false;
    for (int32_t i = 0; i < (int32_t)instance_layers->count; i++) {
        struct loader_layer_properties *prop = &instance_layers->list[i];

        // If this is a meta-layer, make sure it is valid
        if ((prop->type_flags & VK_LAYER_TYPE_FLAG_META_LAYER) &&
            !verify_meta_layer_component_layers(inst, prop, instance_layers)) {
            loader_log(inst, VULKAN_LOADER_DEBUG_BIT, 0,
                       "Removing meta-layer %s from instance layer list since it appears invalid.", prop->info.layerName);

            loader_remove_layer_in_list(inst, instance_layers, i);
            i--;

        } else if (prop->is_override && loader_implicit_layer_is_enabled(inst, enable_filter, disable_filter, prop)) {
            *override_layer_present = true;
        }
    }
}

// If the current working directory matches any app_key_path of the layers, remove all other override layers.
// Otherwise if no matching app_key was found, remove all but the global override layer, which has no app_key_path.
static void remove_all_non_valid_override_layers(struct loader_instance *inst, struct loader_layer_list *instance_layers) {
    if (instance_layers == NULL) {
        return;
    }

    char cur_path[MAX_STRING_SIZE];
    char *ret = loader_platform_executable_path(cur_path, sizeof(cur_path));
    if (ret == NULL) {
        loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                   "remove_all_non_valid_override_layers: Failed to get executable path and name");
        return;
    }

    // Find out if there is an override layer with same the app_key_path as the path to the current executable.
    // If more than one is found, remove it and use the first layer
    // Remove any layers which aren't global and do not have the same app_key_path as the path to the current executable.
    bool found_active_override_layer = false;
    int global_layer_index = -1;
    for (uint32_t i = 0; i < instance_layers->count; i++) {
        struct loader_layer_properties *props = &instance_layers->list[i];
        if (strcmp(props->info.layerName, VK_OVERRIDE_LAYER_NAME) == 0) {
            if (props->num_app_key_paths > 0) {  // not the global layer
                for (uint32_t j = 0; j < props->num_app_key_paths; j++) {
                    if (strcmp(props->app_key_paths[j], cur_path) == 0) {
                        if (!found_active_override_layer) {
                            found_active_override_layer = true;
                        } else {
                            loader_log(inst, VULKAN_LOADER_WARN_BIT | VULKAN_LOADER_LAYER_BIT, 0,
                                       "remove_all_non_valid_override_layers: Multiple override layers where the same path in "
                                       "app_keys "
                                       "was found. Using the first layer found");

                            // Remove duplicate active override layers that have the same app_key_path
                            loader_remove_layer_in_list(inst, instance_layers, i);
                            i--;
                        }
                    }
                }
                if (!found_active_override_layer) {
                    loader_log(inst, VULKAN_LOADER_INFO_BIT | VULKAN_LOADER_LAYER_BIT, 0,
                               "--Override layer found but not used because app \'%s\' is not in \'app_keys\' list!", cur_path);

                    // Remove non-global override layers that don't have an app_key that matches cur_path
                    loader_remove_layer_in_list(inst, instance_layers, i);
                    i--;
                }
            } else {
                if (global_layer_index == -1) {
                    global_layer_index = i;
                } else {
                    loader_log(
                        inst, VULKAN_LOADER_WARN_BIT | VULKAN_LOADER_LAYER_BIT, 0,
                        "remove_all_non_valid_override_layers: Multiple global override layers found. Using the first global "
                        "layer found");
                    loader_remove_layer_in_list(inst, instance_layers, i);
                    i--;
                }
            }
        }
    }
    // Remove global layer if layer with same the app_key_path as the path to the current executable is found
    if (found_active_override_layer && global_layer_index >= 0) {
        loader_remove_layer_in_list(inst, instance_layers, global_layer_index);
    }
    // Should be at most 1 override layer in the list now.
    if (found_active_override_layer) {
        loader_log(inst, VULKAN_LOADER_INFO_BIT | VULKAN_LOADER_LAYER_BIT, 0, "Using the override layer for app key %s", cur_path);
    } else if (global_layer_index >= 0) {
        loader_log(inst, VULKAN_LOADER_INFO_BIT | VULKAN_LOADER_LAYER_BIT, 0, "Using the global override layer");
    }
}

static VkResult loader_read_layer_json(const struct loader_instance *inst, struct loader_layer_list *layer_instance_list,
                                       cJSON *layer_node, loader_api_version version, cJSON *item, bool is_implicit,
                                       char *filename) {
    char *temp;
    char *name, *type, *library_path_str, *api_version;
    char *implementation_version, *description;
    cJSON *ext_item;
    cJSON *library_path;
    cJSON *component_layers;
    cJSON *override_paths;
    cJSON *blacklisted_layers;
    cJSON *disable_environment = NULL;
    VkExtensionProperties ext_prop;
    VkResult result = VK_ERROR_INITIALIZATION_FAILED;
    struct loader_layer_properties *props = NULL;
    uint32_t props_index = 0;
    int i, j;

// The following are required in the "layer" object:
// (required) "name"
// (required) "type"
// (required) "library_path"
// (required) "api_version"
// (required) "implementation_version"
// (required) "description"
// (required for implicit layers) "disable_environment"
#define GET_JSON_OBJECT(node, var)                                         \
    {                                                                      \
        var = cJSON_GetObjectItem(node, #var);                             \
        if (var == NULL) {                                                 \
            loader_log(inst, VULKAN_LOADER_WARN_BIT, 0,                    \
                       "Didn't find required layer object %s in manifest " \
                       "JSON file, skipping this layer",                   \
                       #var);                                              \
            goto out;                                                      \
        }                                                                  \
    }
#define GET_JSON_ITEM(inst, node, var)                                         \
    {                                                                          \
        item = cJSON_GetObjectItem(node, #var);                                \
        if (item == NULL) {                                                    \
            loader_log(inst, VULKAN_LOADER_WARN_BIT, 0,                        \
                       "Didn't find required layer value %s in manifest JSON " \
                       "file, skipping this layer",                            \
                       #var);                                                  \
            goto out;                                                          \
        }                                                                      \
        temp = cJSON_Print(item);                                              \
        if (temp == NULL) {                                                    \
            loader_log(inst, VULKAN_LOADER_WARN_BIT, 0,                        \
                       "Problem accessing layer value %s in manifest JSON "    \
                       "file, skipping this layer",                            \
                       #var);                                                  \
            result = VK_ERROR_OUT_OF_HOST_MEMORY;                              \
            goto out;                                                          \
        }                                                                      \
        temp[strlen(temp) - 1] = '\0';                                         \
        var = loader_stack_alloc(strlen(temp) + 1);                            \
        strcpy(var, &temp[1]);                                                 \
        loader_instance_heap_free(inst, temp);                                 \
    }
    GET_JSON_ITEM(inst, layer_node, name)
    GET_JSON_ITEM(inst, layer_node, type)
    GET_JSON_ITEM(inst, layer_node, api_version)
    GET_JSON_ITEM(inst, layer_node, implementation_version)
    GET_JSON_ITEM(inst, layer_node, description)

    // Add list entry
    if (!strcmp(type, "DEVICE")) {
        loader_log(inst, VULKAN_LOADER_WARN_BIT | VULKAN_LOADER_LAYER_BIT, 0, "Device layers are deprecated. Skipping this layer");
        goto out;
    }

    // Allow either GLOBAL or INSTANCE type interchangeably to handle
    // layers that must work with older loaders
    if (!strcmp(type, "INSTANCE") || !strcmp(type, "GLOBAL")) {
        if (layer_instance_list == NULL) {
            goto out;
        }
        props = loader_get_next_layer_property_slot(inst, layer_instance_list);
        if (NULL == props) {
            // Error already triggered in loader_get_next_layer_property_slot.
            result = VK_ERROR_OUT_OF_HOST_MEMORY;
            goto out;
        }
        props_index = layer_instance_list->count - 1;
        props->type_flags = VK_LAYER_TYPE_FLAG_INSTANCE_LAYER;
        if (!is_implicit) {
            props->type_flags |= VK_LAYER_TYPE_FLAG_EXPLICIT_LAYER;
        }
    } else {
        goto out;
    }

    // Check if this layer's name matches the override layer name, set is_override to true if so.
    if (!strcmp(name, VK_OVERRIDE_LAYER_NAME)) {
        props->is_override = true;
    }

    // Library path no longer required unless component_layers is also not defined
    library_path = cJSON_GetObjectItem(layer_node, "library_path");
    component_layers = cJSON_GetObjectItem(layer_node, "component_layers");
    if (NULL != library_path) {
        if (NULL != component_layers) {
            loader_log(inst, VULKAN_LOADER_WARN_BIT, 0,
                       "Indicating meta-layer-specific component_layers, but also defining layer library path.  Both are not "
                       "compatible, so skipping this layer");
            goto out;
        }
        props->num_component_layers = 0;
        props->component_layer_names = NULL;

        temp = cJSON_Print(library_path);
        if (NULL == temp) {
            loader_log(inst, VULKAN_LOADER_WARN_BIT, 0,
                       "Problem accessing layer value library_path in manifest JSON file, skipping this layer");
            result = VK_ERROR_OUT_OF_HOST_MEMORY;
            goto out;
        }
        temp[strlen(temp) - 1] = '\0';
        library_path_str = loader_stack_alloc(strlen(temp) + 1);
        strcpy(library_path_str, &temp[1]);
        loader_instance_heap_free(inst, temp);

        strncpy(props->manifest_file_name, filename, MAX_STRING_SIZE);
        char *fullpath = props->lib_name;
        char *rel_base;
        if (NULL != library_path_str) {
            if (loader_platform_is_path(library_path_str)) {
                // A relative or absolute path
                char *name_copy = loader_stack_alloc(strlen(filename) + 1);
                strcpy(name_copy, filename);
                rel_base = loader_platform_dirname(name_copy);
                loader_expand_path(library_path_str, rel_base, MAX_STRING_SIZE, fullpath);
            } else {
                // A filename which is assumed in a system directory
                loader_get_fullpath(library_path_str, "", MAX_STRING_SIZE, fullpath);
            }
        }
    } else if (NULL != component_layers) {
        if (!loader_check_version_meets_required(LOADER_VERSION_1_1_0, version)) {
            loader_log(inst, VULKAN_LOADER_WARN_BIT, 0,
                       "Indicating meta-layer-specific component_layers, but using older JSON file version.");
        }
        int count = cJSON_GetArraySize(component_layers);
        props->num_component_layers = count;

        // Allocate buffer for layer names
        props->component_layer_names =
            loader_instance_heap_alloc(inst, sizeof(char[MAX_STRING_SIZE]) * count, VK_SYSTEM_ALLOCATION_SCOPE_INSTANCE);
        if (NULL == props->component_layer_names && count > 0) {
            result = VK_ERROR_OUT_OF_HOST_MEMORY;
            goto out;
        }

        // Copy the component layers into the array
        for (i = 0; i < count; i++) {
            cJSON *comp_layer = cJSON_GetArrayItem(component_layers, i);
            if (NULL != comp_layer) {
                temp = cJSON_Print(comp_layer);
                if (NULL == temp) {
                    result = VK_ERROR_OUT_OF_HOST_MEMORY;
                    goto out;
                }
                temp[strlen(temp) - 1] = '\0';
                strncpy(props->component_layer_names[i], temp + 1, MAX_STRING_SIZE - 1);
                props->component_layer_names[i][MAX_STRING_SIZE - 1] = '\0';
                loader_instance_heap_free(inst, temp);
            }
        }

        // This is now, officially, a meta-layer
        props->type_flags |= VK_LAYER_TYPE_FLAG_META_LAYER;
        loader_log(inst, VULKAN_LOADER_INFO_BIT | VULKAN_LOADER_LAYER_BIT, 0, "Encountered meta-layer \"%s\"", name);

        // Make sure we set up other things so we head down the correct branches below
        library_path_str = NULL;
    } else {
        loader_log(inst, VULKAN_LOADER_WARN_BIT, 0,
                   "Layer missing both library_path and component_layers fields.  One or the other MUST be defined.  Skipping "
                   "this layer");
        goto out;
    }

    props->num_blacklist_layers = 0;
    props->blacklist_layer_names = NULL;
    blacklisted_layers = cJSON_GetObjectItem(layer_node, "blacklisted_layers");
    if (blacklisted_layers != NULL) {
        if (strcmp(name, VK_OVERRIDE_LAYER_NAME)) {
            loader_log(inst, VULKAN_LOADER_WARN_BIT, 0,
                       "Layer \"%s\" contains a blacklist, but a blacklist can only be provided by the override metalayer. This "
                       "blacklist will be ignored.",
                       name);
        } else {
            props->num_blacklist_layers = cJSON_GetArraySize(blacklisted_layers);
            if (props->num_blacklist_layers > 0) {
                // Allocate the blacklist array
                props->blacklist_layer_names = loader_instance_heap_alloc(
                    inst, sizeof(char[MAX_STRING_SIZE]) * props->num_blacklist_layers, VK_SYSTEM_ALLOCATION_SCOPE_INSTANCE);
                if (props->blacklist_layer_names == NULL && props->num_blacklist_layers > 0) {
                    result = VK_ERROR_OUT_OF_HOST_MEMORY;
                    goto out;
                }

                // Copy the blacklisted layers into the array
                for (i = 0; i < (int)props->num_blacklist_layers; ++i) {
                    cJSON *black_layer = cJSON_GetArrayItem(blacklisted_layers, i);
                    if (black_layer == NULL) {
                        continue;
                    }
                    temp = cJSON_Print(black_layer);
                    if (temp == NULL) {
                        result = VK_ERROR_OUT_OF_HOST_MEMORY;
                        goto out;
                    }
                    temp[strlen(temp) - 1] = '\0';
                    strncpy(props->blacklist_layer_names[i], temp + 1, MAX_STRING_SIZE - 1);
                    props->blacklist_layer_names[i][MAX_STRING_SIZE - 1] = '\0';
                    loader_instance_heap_free(inst, temp);
                }
            }
        }
    }

    override_paths = cJSON_GetObjectItem(layer_node, "override_paths");
    if (NULL != override_paths) {
        if (!loader_check_version_meets_required(loader_combine_version(1, 1, 0), version)) {
            loader_log(inst, VULKAN_LOADER_WARN_BIT, 0,
                       "Indicating meta-layer-specific override paths, but using older JSON file version.");
        }
        int count = cJSON_GetArraySize(override_paths);
        props->num_override_paths = count;
        if (count > 0) {
            // Allocate buffer for override paths
            props->override_paths =
                loader_instance_heap_alloc(inst, sizeof(char[MAX_STRING_SIZE]) * count, VK_SYSTEM_ALLOCATION_SCOPE_INSTANCE);
            if (NULL == props->override_paths && count > 0) {
                result = VK_ERROR_OUT_OF_HOST_MEMORY;
                goto out;
            }

            // Copy the override paths into the array
            for (i = 0; i < count; i++) {
                cJSON *override_path = cJSON_GetArrayItem(override_paths, i);
                if (NULL != override_path) {
                    temp = cJSON_Print(override_path);
                    if (NULL == temp) {
                        result = VK_ERROR_OUT_OF_HOST_MEMORY;
                        goto out;
                    }
                    temp[strlen(temp) - 1] = '\0';
                    strncpy(props->override_paths[i], temp + 1, MAX_STRING_SIZE - 1);
                    props->override_paths[i][MAX_STRING_SIZE - 1] = '\0';
                    loader_instance_heap_free(inst, temp);
                }
            }
        }
    }

    if (is_implicit) {
        GET_JSON_OBJECT(layer_node, disable_environment)
    }
#undef GET_JSON_ITEM
#undef GET_JSON_OBJECT

    strncpy(props->info.layerName, name, sizeof(props->info.layerName));
    props->info.layerName[sizeof(props->info.layerName) - 1] = '\0';
    if (0 != strncmp(props->info.layerName, "VK_LAYER_", 9)) {
        loader_log(inst, VULKAN_LOADER_WARN_BIT, 0, "Layer name %s does not conform to naming standard (Policy #LLP_LAYER_3)",
                   props->info.layerName);
    }
    props->info.specVersion = loader_parse_version_string(api_version);
    props->info.implementationVersion = atoi(implementation_version);
    strncpy((char *)props->info.description, description, sizeof(props->info.description));
    props->info.description[sizeof(props->info.description) - 1] = '\0';
    if (is_implicit) {
        if (!disable_environment || !disable_environment->child) {
            loader_log(inst, VULKAN_LOADER_WARN_BIT, 0,
                       "Didn't find required layer child value disable_environment in manifest JSON file, skipping this layer "
                       "(Policy #LLP_LAYER_9)");
            goto out;
        }
        strncpy(props->disable_env_var.name, disable_environment->child->string, sizeof(props->disable_env_var.name));
        props->disable_env_var.name[sizeof(props->disable_env_var.name) - 1] = '\0';
        strncpy(props->disable_env_var.value, disable_environment->child->valuestring, sizeof(props->disable_env_var.value));
        props->disable_env_var.value[sizeof(props->disable_env_var.value) - 1] = '\0';
    }

    // Make sure the layer's manifest doesn't contain a non zero variant value
    if (VK_API_VERSION_VARIANT(props->info.specVersion) != 0) {
        loader_log(inst, VULKAN_LOADER_INFO_BIT | VULKAN_LOADER_LAYER_BIT, 0,
                   "Layer \"%s\" has an \'api_version\' field which contains a non-zero variant value of %d. "
                   " Skipping Layer.",
                   props->info.layerName, VK_API_VERSION_VARIANT(props->info.specVersion));
        goto out;
    }

// Now get all optional items and objects and put in list:
// functions
// instance_extensions
// device_extensions
// enable_environment (implicit layers only)
// library_arch
#define GET_JSON_OBJECT(node, var) \
    { var = cJSON_GetObjectItem(node, #var); }
#define GET_JSON_ITEM(inst, node, var)                      \
    {                                                       \
        item = cJSON_GetObjectItem(node, #var);             \
        if (item != NULL) {                                 \
            temp = cJSON_Print(item);                       \
            if (temp != NULL) {                             \
                temp[strlen(temp) - 1] = '\0';              \
                var = loader_stack_alloc(strlen(temp) + 1); \
                strcpy(var, &temp[1]);                      \
                loader_instance_heap_free(inst, temp);      \
            } else {                                        \
                result = VK_ERROR_OUT_OF_HOST_MEMORY;       \
                goto out;                                   \
            }                                               \
        }                                                   \
    }

    cJSON *instance_extensions, *device_extensions, *functions, *enable_environment;
    cJSON *entrypoints = NULL;
    char *vkGetInstanceProcAddr = NULL;
    char *vkGetDeviceProcAddr = NULL;
    char *vkNegotiateLoaderLayerInterfaceVersion = NULL;
    char *spec_version = NULL;
    char **entry_array = NULL;
    char *library_arch = NULL;
    cJSON *app_keys = NULL;

    // Layer interface functions
    //    vkGetInstanceProcAddr
    //    vkGetDeviceProcAddr
    //    vkNegotiateLoaderLayerInterfaceVersion (starting with JSON file 1.1.0)
    GET_JSON_OBJECT(layer_node, functions)
    if (functions != NULL) {
        if (loader_check_version_meets_required(loader_combine_version(1, 1, 0), version)) {
            GET_JSON_ITEM(inst, functions, vkNegotiateLoaderLayerInterfaceVersion)
            if (vkNegotiateLoaderLayerInterfaceVersion != NULL)
                strncpy(props->functions.str_negotiate_interface, vkNegotiateLoaderLayerInterfaceVersion,
                        sizeof(props->functions.str_negotiate_interface));
            props->functions.str_negotiate_interface[sizeof(props->functions.str_negotiate_interface) - 1] = '\0';
        } else {
            props->functions.str_negotiate_interface[0] = '\0';
        }
        GET_JSON_ITEM(inst, functions, vkGetInstanceProcAddr)
        GET_JSON_ITEM(inst, functions, vkGetDeviceProcAddr)
        if (vkGetInstanceProcAddr != NULL) {
            strncpy(props->functions.str_gipa, vkGetInstanceProcAddr, sizeof(props->functions.str_gipa));
            if (loader_check_version_meets_required(loader_combine_version(1, 1, 0), version)) {
                loader_log(inst, VULKAN_LOADER_INFO_BIT, 0,
                           "Layer \"%s\" using deprecated \'vkGetInstanceProcAddr\' tag which was deprecated starting with JSON "
                           "file version 1.1.0. The new vkNegotiateLoaderLayerInterfaceVersion function is preferred, though for "
                           "compatibility reasons it may be desirable to continue using the deprecated tag.",
                           name);
            }
        }
        props->functions.str_gipa[sizeof(props->functions.str_gipa) - 1] = '\0';
        if (vkGetDeviceProcAddr != NULL) {
            strncpy(props->functions.str_gdpa, vkGetDeviceProcAddr, sizeof(props->functions.str_gdpa));
            if (loader_check_version_meets_required(loader_combine_version(1, 1, 0), version)) {
                loader_log(inst, VULKAN_LOADER_INFO_BIT, 0,
                           "Layer \"%s\" using deprecated \'vkGetDeviceProcAddr\' tag which was deprecated starting with JSON "
                           "file version 1.1.0. The new vkNegotiateLoaderLayerInterfaceVersion function is preferred, though for "
                           "compatibility reasons it may be desirable to continue using the deprecated tag.",
                           name);
            }
        }
        props->functions.str_gdpa[sizeof(props->functions.str_gdpa) - 1] = '\0';
    }

    // instance_extensions
    //   array of {
    //     name
    //     spec_version
    //   }
    GET_JSON_OBJECT(layer_node, instance_extensions)
    if (instance_extensions != NULL) {
        int count = cJSON_GetArraySize(instance_extensions);
        for (i = 0; i < count; i++) {
            ext_item = cJSON_GetArrayItem(instance_extensions, i);
            GET_JSON_ITEM(inst, ext_item, name)
            if (name != NULL) {
                strncpy(ext_prop.extensionName, name, sizeof(ext_prop.extensionName));
                ext_prop.extensionName[sizeof(ext_prop.extensionName) - 1] = '\0';
            }
            GET_JSON_ITEM(inst, ext_item, spec_version)
            if (NULL != spec_version) {
                ext_prop.specVersion = atoi(spec_version);
            } else {
                ext_prop.specVersion = 0;
            }
            bool ext_unsupported = wsi_unsupported_instance_extension(&ext_prop);
            if (!ext_unsupported) {
                loader_add_to_ext_list(inst, &props->instance_extension_list, 1, &ext_prop);
            }
        }
    }

    // device_extensions
    //   array of {
    //     name
    //     spec_version
    //     entrypoints
    //   }
    GET_JSON_OBJECT(layer_node, device_extensions)
    if (device_extensions != NULL) {
        int count = cJSON_GetArraySize(device_extensions);
        for (i = 0; i < count; i++) {
            ext_item = cJSON_GetArrayItem(device_extensions, i);
            GET_JSON_ITEM(inst, ext_item, name)
            GET_JSON_ITEM(inst, ext_item, spec_version)
            if (name != NULL) {
                strncpy(ext_prop.extensionName, name, sizeof(ext_prop.extensionName));
                ext_prop.extensionName[sizeof(ext_prop.extensionName) - 1] = '\0';
            }
            if (NULL != spec_version) {
                ext_prop.specVersion = atoi(spec_version);
            } else {
                ext_prop.specVersion = 0;
            }
            // entrypoints = cJSON_GetObjectItem(ext_item, "entrypoints");
            GET_JSON_OBJECT(ext_item, entrypoints)
            int entry_count;
            if (entrypoints == NULL) {
                loader_add_to_dev_ext_list(inst, &props->device_extension_list, &ext_prop, 0, NULL);
                continue;
            }
            entry_count = cJSON_GetArraySize(entrypoints);
            if (entry_count) {
                entry_array = (char **)loader_stack_alloc(sizeof(char *) * entry_count);
            }
            for (j = 0; j < entry_count; j++) {
                ext_item = cJSON_GetArrayItem(entrypoints, j);
                if (ext_item != NULL) {
                    temp = cJSON_Print(ext_item);
                    if (NULL == temp) {
                        entry_array[j] = NULL;
                        result = VK_ERROR_OUT_OF_HOST_MEMORY;
                        goto out;
                    }
                    temp[strlen(temp) - 1] = '\0';
                    entry_array[j] = loader_stack_alloc(strlen(temp) + 1);
                    strcpy(entry_array[j], &temp[1]);
                    loader_instance_heap_free(inst, temp);
                }
            }
            loader_add_to_dev_ext_list(inst, &props->device_extension_list, &ext_prop, entry_count, entry_array);
        }
    }
    if (is_implicit) {
        GET_JSON_OBJECT(layer_node, enable_environment)

        // enable_environment is optional
        if (enable_environment) {
            strncpy(props->enable_env_var.name, enable_environment->child->string, sizeof(props->enable_env_var.name));
            props->enable_env_var.name[sizeof(props->enable_env_var.name) - 1] = '\0';
            strncpy(props->enable_env_var.value, enable_environment->child->valuestring, sizeof(props->enable_env_var.value));
            props->enable_env_var.value[sizeof(props->enable_env_var.value) - 1] = '\0';
        }
    }

    // Read in the pre-instance stuff
    cJSON *pre_instance = cJSON_GetObjectItem(layer_node, "pre_instance_functions");
    if (NULL != pre_instance) {
        // Supported versions started in 1.1.2, so anything newer
        if (!loader_check_version_meets_required(loader_combine_version(1, 1, 2), version)) {
            loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                       "Found pre_instance_functions section in layer from \"%s\". This section is only valid in manifest version "
                       "1.1.2 or later. The section will be ignored",
                       filename);
        } else if (!is_implicit) {
            loader_log(inst, VULKAN_LOADER_WARN_BIT, 0,
                       "Found pre_instance_functions section in explicit layer from \"%s\". This section is only valid in implicit "
                       "layers. The section will be ignored",
                       filename);
        } else {
            cJSON *inst_ext_json = cJSON_GetObjectItem(pre_instance, "vkEnumerateInstanceExtensionProperties");
            if (NULL != inst_ext_json) {
                char *inst_ext_name = cJSON_Print(inst_ext_json);
                if (NULL == inst_ext_name) {
                    result = VK_ERROR_OUT_OF_HOST_MEMORY;
                    goto out;
                }
                size_t len = strlen(inst_ext_name) >= MAX_STRING_SIZE ? MAX_STRING_SIZE - 3 : strlen(inst_ext_name) - 2;
                strncpy(props->pre_instance_functions.enumerate_instance_extension_properties, inst_ext_name + 1, len);
                props->pre_instance_functions.enumerate_instance_extension_properties[len] = '\0';
                loader_instance_heap_free(inst, inst_ext_name);
            }

            cJSON *inst_layer_json = cJSON_GetObjectItem(pre_instance, "vkEnumerateInstanceLayerProperties");
            if (NULL != inst_layer_json) {
                char *inst_layer_name = cJSON_Print(inst_layer_json);
                if (NULL == inst_layer_name) {
                    result = VK_ERROR_OUT_OF_HOST_MEMORY;
                    goto out;
                }
                size_t len = strlen(inst_layer_name) >= MAX_STRING_SIZE ? MAX_STRING_SIZE - 3 : strlen(inst_layer_name) - 2;
                strncpy(props->pre_instance_functions.enumerate_instance_layer_properties, inst_layer_name + 1, len);
                props->pre_instance_functions.enumerate_instance_layer_properties[len] = '\0';
                loader_instance_heap_free(inst, inst_layer_name);
            }

            cJSON *inst_version_json = cJSON_GetObjectItem(pre_instance, "vkEnumerateInstanceVersion");
            if (NULL != inst_version_json) {
                char *inst_version_name = cJSON_Print(inst_version_json);
                if (NULL == inst_version_name) {
                    result = VK_ERROR_OUT_OF_HOST_MEMORY;
                    goto out;
                }
                size_t len = strlen(inst_version_name) >= MAX_STRING_SIZE ? MAX_STRING_SIZE - 3 : strlen(inst_version_name) - 2;
                strncpy(props->pre_instance_functions.enumerate_instance_version, inst_version_name + 1, len);
                props->pre_instance_functions.enumerate_instance_version[len] = '\0';
                loader_instance_heap_free(inst, inst_version_name);
            }
        }
    }

    props->num_app_key_paths = 0;
    props->app_key_paths = NULL;
    app_keys = cJSON_GetObjectItem(layer_node, "app_keys");
    if (app_keys != NULL) {
        if (strcmp(name, VK_OVERRIDE_LAYER_NAME)) {
            loader_log(inst, VULKAN_LOADER_WARN_BIT | VULKAN_LOADER_LAYER_BIT, 0,
                       "Layer %s contains app_keys, but any app_keys can only be provided by the override metalayer. "
                       "These will be ignored.",
                       name);
        } else {
            props->num_app_key_paths = cJSON_GetArraySize(app_keys);

            // Allocate the blacklist array
            props->app_key_paths = loader_instance_heap_alloc(inst, sizeof(char[MAX_STRING_SIZE]) * props->num_app_key_paths,
                                                              VK_SYSTEM_ALLOCATION_SCOPE_INSTANCE);
            if (props->app_key_paths == NULL) {
                result = VK_ERROR_OUT_OF_HOST_MEMORY;
                goto out;
            }

            // Copy the app_key_paths into the array
            for (i = 0; i < (int)props->num_app_key_paths; ++i) {
                cJSON *app_key_path = cJSON_GetArrayItem(app_keys, i);
                if (app_key_path == NULL) {
                    continue;
                }
                temp = cJSON_Print(app_key_path);
                if (temp == NULL) {
                    result = VK_ERROR_OUT_OF_HOST_MEMORY;
                    goto out;
                }
                temp[strlen(temp) - 1] = '\0';
                strncpy(props->app_key_paths[i], temp + 1, MAX_STRING_SIZE - 1);
                props->app_key_paths[i][MAX_STRING_SIZE - 1] = '\0';
                loader_instance_heap_free(inst, temp);
            }
        }
    }

    GET_JSON_ITEM(inst, layer_node, library_arch)
    if (library_arch != NULL) {
        if ((strncmp(library_arch, "32", 2) == 0 && sizeof(void *) != 4) ||
            (strncmp(library_arch, "64", 2) == 0 && sizeof(void *) != 8)) {
            loader_log(inst, VULKAN_LOADER_INFO_BIT, 0,
                       "Layer library architecture doesn't match the current running architecture, skipping this layer");
            goto out;
        }
    }

    result = VK_SUCCESS;

out:
#undef GET_JSON_ITEM
#undef GET_JSON_OBJECT

    if (VK_SUCCESS != result && NULL != props) {
        // Make sure to free anything that was allocated
        loader_remove_layer_in_list(inst, layer_instance_list, props_index);
    }

    return result;
}

static inline bool is_valid_layer_json_version(const loader_api_version *layer_json) {
    // Supported versions are: 1.0.0, 1.0.1, 1.1.0 - 1.1.2, and 1.2.0 - 1.2.1.
    if ((layer_json->major == 1 && layer_json->minor == 2 && layer_json->patch < 2) ||
        (layer_json->major == 1 && layer_json->minor == 1 && layer_json->patch < 3) ||
        (layer_json->major == 1 && layer_json->minor == 0 && layer_json->patch < 2)) {
        return true;
    }
    return false;
}

// Given a cJSON struct (json) of the top level JSON object from layer manifest
// file, add entry to the layer_list. Fill out the layer_properties in this list
// entry from the input cJSON object.
//
// \returns
// void
// layer_list has a new entry and initialized accordingly.
// If the json input object does not have all the required fields no entry
// is added to the list.
static VkResult loader_add_layer_properties(const struct loader_instance *inst, struct loader_layer_list *layer_instance_list,
                                            cJSON *json, bool is_implicit, char *filename) {
    // The following Fields in layer manifest file that are required:
    //   - "file_format_version"
    //   - If more than one "layer" object are used, then the "layers" array is
    //     required
    VkResult result = VK_ERROR_INITIALIZATION_FAILED;
    cJSON *item, *layers_node, *layer_node;
    loader_api_version json_version = {0, 0, 0};
    char *file_vers = NULL;
    // Make sure sure the top level json value is an object
    if (!json || json->type != 6) {
        goto out;
    }
    item = cJSON_GetObjectItem(json, "file_format_version");
    if (item == NULL) {
        goto out;
    }
    file_vers = cJSON_PrintUnformatted(item);
    if (NULL == file_vers) {
        result = VK_ERROR_OUT_OF_HOST_MEMORY;
        goto out;
    }
    loader_log(inst, VULKAN_LOADER_INFO_BIT, 0, "Found manifest file %s (file version %s)", filename, file_vers);
    // Get the major/minor/and patch as integers for easier comparison
    json_version = loader_make_full_version(loader_parse_version_string(file_vers));

    if (!is_valid_layer_json_version(&json_version)) {
        loader_log(inst, VULKAN_LOADER_INFO_BIT | VULKAN_LOADER_LAYER_BIT, 0,
                   "loader_add_layer_properties: %s has unknown layer manifest file version %d.%d.%d.  May cause errors.", filename,
                   json_version.major, json_version.minor, json_version.patch);
    }

    // If "layers" is present, read in the array of layer objects
    layers_node = cJSON_GetObjectItem(json, "layers");
    if (layers_node != NULL) {
        int numItems = cJSON_GetArraySize(layers_node);
        // Supported versions started in 1.0.1, so anything newer
        if (!loader_check_version_meets_required(loader_combine_version(1, 0, 1), json_version)) {
            loader_log(inst, VULKAN_LOADER_WARN_BIT | VULKAN_LOADER_LAYER_BIT, 0,
                       "loader_add_layer_properties: \'layers\' tag not supported until file version 1.0.1, but %s is reporting "
                       "version %s",
                       filename, file_vers);
        }
        for (int curLayer = 0; curLayer < numItems; curLayer++) {
            layer_node = cJSON_GetArrayItem(layers_node, curLayer);
            if (layer_node == NULL) {
                loader_log(inst, VULKAN_LOADER_WARN_BIT | VULKAN_LOADER_LAYER_BIT, 0,
                           "loader_add_layer_properties: Can not find 'layers' array element %d object in manifest JSON file %s.  "
                           "Skipping this file",
                           curLayer, filename);
                goto out;
            }
            result = loader_read_layer_json(inst, layer_instance_list, layer_node, json_version, item, is_implicit, filename);
        }
    } else {
        // Otherwise, try to read in individual layers
        layer_node = cJSON_GetObjectItem(json, "layer");
        if (layer_node == NULL) {
            loader_log(inst, VULKAN_LOADER_WARN_BIT | VULKAN_LOADER_LAYER_BIT, 0,
                       "loader_add_layer_properties: Can not find 'layer' object in manifest JSON file %s.  Skipping this file.",
                       filename);
            goto out;
        }
        // Loop through all "layer" objects in the file to get a count of them
        // first.
        uint16_t layer_count = 0;
        cJSON *tempNode = layer_node;
        do {
            tempNode = tempNode->next;
            layer_count++;
        } while (tempNode != NULL);

        // Throw a warning if we encounter multiple "layer" objects in file
        // versions newer than 1.0.0.  Having multiple objects with the same
        // name at the same level is actually a JSON standard violation.
        if (layer_count > 1 && loader_check_version_meets_required(loader_combine_version(1, 0, 1), json_version)) {
            loader_log(inst, VULKAN_LOADER_ERROR_BIT | VULKAN_LOADER_LAYER_BIT, 0,
                       "loader_add_layer_properties: Multiple 'layer' nodes are deprecated starting in file version \"1.0.1\".  "
                       "Please use 'layers' : [] array instead in %s.",
                       filename);
        } else {
            do {
                result = loader_read_layer_json(inst, layer_instance_list, layer_node, json_version, item, is_implicit, filename);
                layer_node = layer_node->next;
            } while (layer_node != NULL);
        }
    }

out:
    loader_instance_heap_free(inst, file_vers);

    return result;
}

static inline size_t determine_data_file_path_size(const char *cur_path, size_t relative_path_size) {
    size_t path_size = 0;

    if (NULL != cur_path) {
        // For each folder in cur_path, (detected by finding additional
        // path separators in the string) we need to add the relative path on
        // the end.  Plus, leave an additional two slots on the end to add an
        // additional directory slash and path separator if needed
        path_size += strlen(cur_path) + relative_path_size + 2;
        for (const char *x = cur_path; *x; ++x) {
            if (*x == PATH_SEPARATOR) {
                path_size += relative_path_size + 2;
            }
        }
    }

    return path_size;
}

static inline void copy_data_file_info(const char *cur_path, const char *relative_path, size_t relative_path_size,
                                       char **output_path) {
    if (NULL != cur_path) {
        uint32_t start = 0;
        uint32_t stop = 0;
        char *cur_write = *output_path;

        while (cur_path[start] != '\0') {
            while (cur_path[start] == PATH_SEPARATOR) {
                start++;
            }
            stop = start;
            while (cur_path[stop] != PATH_SEPARATOR && cur_path[stop] != '\0') {
                stop++;
            }
            const size_t s = stop - start;
            if (s) {
                memcpy(cur_write, &cur_path[start], s);
                cur_write += s;

                // If this is a specific JSON file, just add it and don't add any
                // relative path or directory symbol to it.
                if (!is_json(cur_write - 5, s)) {
                    // Add the relative directory if present.
                    if (relative_path_size > 0) {
                        // If last symbol written was not a directory symbol, add it.
                        if (*(cur_write - 1) != DIRECTORY_SYMBOL) {
                            *cur_write++ = DIRECTORY_SYMBOL;
                        }
                        memcpy(cur_write, relative_path, relative_path_size);
                        cur_write += relative_path_size;
                    }
                }

                *cur_write++ = PATH_SEPARATOR;
                start = stop;
            }
        }
        *output_path = cur_write;
    }
}

// Check to see if there's enough space in the data file list.  If not, add some.
static inline VkResult check_and_adjust_data_file_list(const struct loader_instance *inst, struct loader_data_files *out_files) {
    if (out_files->count == 0) {
        out_files->filename_list = loader_instance_heap_alloc(inst, 64 * sizeof(char *), VK_SYSTEM_ALLOCATION_SCOPE_COMMAND);
        if (NULL == out_files->filename_list) {
            loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                       "check_and_adjust_data_file_list: Failed to allocate space for manifest file name list");
            return VK_ERROR_OUT_OF_HOST_MEMORY;
        }
        out_files->alloc_count = 64;
    } else if (out_files->count == out_files->alloc_count) {
        size_t new_size = out_files->alloc_count * sizeof(char *) * 2;
        void *new_ptr = loader_instance_heap_realloc(inst, out_files->filename_list, out_files->alloc_count * sizeof(char *),
                                                     new_size, VK_SYSTEM_ALLOCATION_SCOPE_COMMAND);
        if (NULL == new_ptr) {
            loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                       "check_and_adjust_data_file_list: Failed to reallocate space for manifest file name list");
            return VK_ERROR_OUT_OF_HOST_MEMORY;
        }
        out_files->filename_list = new_ptr;
        out_files->alloc_count *= 2;
    }

    return VK_SUCCESS;
}

// add file_name to the out_files manifest list. Assumes its a valid manifest file name
static VkResult add_manifest_file(const struct loader_instance *inst, const char *file_name, struct loader_data_files *out_files) {
    VkResult vk_result = VK_SUCCESS;

    // Check and allocate space in the manifest list if necessary
    vk_result = check_and_adjust_data_file_list(inst, out_files);
    if (VK_SUCCESS != vk_result) {
        goto out;
    }

    out_files->filename_list[out_files->count] =
        loader_instance_heap_alloc(inst, strlen(file_name) + 1, VK_SYSTEM_ALLOCATION_SCOPE_COMMAND);
    if (out_files->filename_list[out_files->count] == NULL) {
        loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0, "add_manifest_file: Failed to allocate space for manifest file %d list",
                   out_files->count);
        vk_result = VK_ERROR_OUT_OF_HOST_MEMORY;
        goto out;
    }

    strcpy(out_files->filename_list[out_files->count++], file_name);

out:
    return vk_result;
}

// If the file found is a manifest file name, add it to the out_files manifest list.
static VkResult add_if_manifest_file(const struct loader_instance *inst, const char *file_name,
                                     struct loader_data_files *out_files) {
    VkResult vk_result = VK_SUCCESS;

    assert(NULL != file_name && "add_if_manifest_file: Received NULL pointer for file_name");
    assert(NULL != out_files && "add_if_manifest_file: Received NULL pointer for out_files");

    // Look for files ending with ".json" suffix
    size_t name_len = strlen(file_name);
    const char *name_suffix = file_name + name_len - 5;
    if (!is_json(name_suffix, name_len)) {
        // Use incomplete to indicate invalid name, but to keep going.
        vk_result = VK_INCOMPLETE;
        goto out;
    }

    vk_result = add_manifest_file(inst, file_name, out_files);

out:

    return vk_result;
}

// Add any files found in the search_path.  If any path in the search path points to a specific JSON, attempt to
// only open that one JSON.  Otherwise, if the path is a folder, search the folder for JSON files.
VkResult add_data_files(const struct loader_instance *inst, char *search_path, struct loader_data_files *out_files,
                        bool use_first_found_manifest) {
    VkResult vk_result = VK_SUCCESS;
    DIR *dir_stream = NULL;
    struct dirent *dir_entry;
    char *cur_file;
    char *next_file;
    char *name;
    char full_path[2048];
#ifndef _WIN32
    char temp_path[2048];
#endif

    // Now, parse the paths
    next_file = search_path;
    while (NULL != next_file && *next_file != '\0') {
        name = NULL;
        cur_file = next_file;
        next_file = loader_get_next_path(cur_file);

        // Is this a JSON file, then try to open it.
        size_t len = strlen(cur_file);
        if (is_json(cur_file + len - 5, len)) {
#ifdef _WIN32
            name = cur_file;
#else
            // Only Linux has relative paths, make a copy of location so it isn't modified
            size_t str_len;
            if (NULL != next_file) {
                str_len = next_file - cur_file + 1;
            } else {
                str_len = strlen(cur_file) + 1;
            }
            if (str_len > sizeof(temp_path)) {
                loader_log(inst, VULKAN_LOADER_DEBUG_BIT, 0, "add_data_files: Path to %s too long", cur_file);
                continue;
            }
            strcpy(temp_path, cur_file);
            name = temp_path;
#endif
            loader_get_fullpath(cur_file, name, sizeof(full_path), full_path);
            name = full_path;

            VkResult local_res;
            local_res = add_if_manifest_file(inst, name, out_files);

            // Incomplete means this was not a valid data file.
            if (local_res == VK_INCOMPLETE) {
                continue;
            } else if (local_res != VK_SUCCESS) {
                vk_result = local_res;
                break;
            }
        } else {  // Otherwise, treat it as a directory
            dir_stream = loader_opendir(inst, cur_file);
            if (NULL == dir_stream) {
                continue;
            }
            while (1) {
                dir_entry = readdir(dir_stream);
                if (NULL == dir_entry) {
                    break;
                }

                name = &(dir_entry->d_name[0]);
                loader_get_fullpath(name, cur_file, sizeof(full_path), full_path);
                name = full_path;

                VkResult local_res;
                local_res = add_if_manifest_file(inst, name, out_files);

                // Incomplete means this was not a valid data file.
                if (local_res == VK_INCOMPLETE) {
                    continue;
                } else if (local_res != VK_SUCCESS) {
                    vk_result = local_res;
                    break;
                }
            }
            loader_closedir(inst, dir_stream);
            if (vk_result != VK_SUCCESS) {
                goto out;
            }
        }
        if (use_first_found_manifest && out_files->count > 0) {
            break;
        }
    }

out:

    return vk_result;
}

// Look for data files in the provided paths, but first check the environment override to determine if we should use that
// instead.
static VkResult read_data_files_in_search_paths(const struct loader_instance *inst, enum loader_data_files_type manifest_type,
                                                const char *path_override, bool *override_active,
                                                struct loader_data_files *out_files) {
    VkResult vk_result = VK_SUCCESS;
    char *override_env = NULL;
    const char *override_path = NULL;
    char *relative_location = NULL;
    char *additional_env = NULL;
    size_t search_path_size = 0;
    char *search_path = NULL;
    char *cur_path_ptr = NULL;
    bool use_first_found_manifest = false;
#ifndef _WIN32
    size_t rel_size = 0;  // unused in windows, dont declare so no compiler warnings are generated
#endif

#if defined(_WIN32)
    char *package_path = NULL;
#else
    // Determine how much space is needed to generate the full search path
    // for the current manifest files.
    char *xdg_config_home = loader_secure_getenv("XDG_CONFIG_HOME", inst);
    char *xdg_config_dirs = loader_secure_getenv("XDG_CONFIG_DIRS", inst);

#if !defined(__Fuchsia__) && !defined(__QNXNTO__)
    if (NULL == xdg_config_dirs || '\0' == xdg_config_dirs[0]) {
        xdg_config_dirs = FALLBACK_CONFIG_DIRS;
    }
#endif

    char *xdg_data_home = loader_secure_getenv("XDG_DATA_HOME", inst);
    char *xdg_data_dirs = loader_secure_getenv("XDG_DATA_DIRS", inst);

#if !defined(__Fuchsia__) && !defined(__QNXNTO__)
    if (NULL == xdg_data_dirs || '\0' == xdg_data_dirs[0]) {
        xdg_data_dirs = FALLBACK_DATA_DIRS;
    }
#endif

    char *home = NULL;
    char *default_data_home = NULL;
    char *default_config_home = NULL;
    char *home_data_dir = NULL;
    char *home_config_dir = NULL;

    // Only use HOME if XDG_DATA_HOME is not present on the system
    home = loader_secure_getenv("HOME", inst);
    if (home != NULL) {
        if (NULL == xdg_config_home || '\0' == xdg_config_home[0]) {
            const char config_suffix[] = "/.config";
            default_config_home =
                loader_instance_heap_alloc(inst, strlen(home) + strlen(config_suffix) + 1, VK_SYSTEM_ALLOCATION_SCOPE_COMMAND);
            if (default_config_home == NULL) {
                vk_result = VK_ERROR_OUT_OF_HOST_MEMORY;
                goto out;
            }
            strcpy(default_config_home, home);
            strcat(default_config_home, config_suffix);
        }
        if (NULL == xdg_data_home || '\0' == xdg_data_home[0]) {
            const char data_suffix[] = "/.local/share";
            default_data_home =
                loader_instance_heap_alloc(inst, strlen(home) + strlen(data_suffix) + 1, VK_SYSTEM_ALLOCATION_SCOPE_COMMAND);
            if (default_data_home == NULL) {
                vk_result = VK_ERROR_OUT_OF_HOST_MEMORY;
                goto out;
            }
            strcpy(default_data_home, home);
            strcat(default_data_home, data_suffix);
        }
    }

    if (NULL != default_config_home) {
        home_config_dir = default_config_home;
    } else {
        home_config_dir = xdg_config_home;
    }
    if (NULL != default_data_home) {
        home_data_dir = default_data_home;
    } else {
        home_data_dir = xdg_data_home;
    }
#endif  // !_WIN32

    switch (manifest_type) {
        case LOADER_DATA_FILE_MANIFEST_DRIVER:
            override_env = loader_secure_getenv(VK_DRIVER_FILES_ENV_VAR, inst);
            if (NULL == override_env) {
                // Not there, so fall back to the old name
                override_env = loader_secure_getenv(VK_ICD_FILENAMES_ENV_VAR, inst);
            }
            additional_env = loader_secure_getenv(VK_ADDITIONAL_DRIVER_FILES_ENV_VAR, inst);
            relative_location = VK_DRIVERS_INFO_RELATIVE_DIR;
#if defined(_WIN32)
            package_path = windows_get_app_package_manifest_path(inst);
#endif
            break;
        case LOADER_DATA_FILE_MANIFEST_IMPLICIT_LAYER:
            relative_location = VK_ILAYERS_INFO_RELATIVE_DIR;
            break;
        case LOADER_DATA_FILE_MANIFEST_EXPLICIT_LAYER:
            override_env = loader_secure_getenv(VK_LAYER_PATH_ENV_VAR, inst);
            additional_env = loader_secure_getenv(VK_ADDITIONAL_LAYER_PATH_ENV_VAR, inst);
            relative_location = VK_ELAYERS_INFO_RELATIVE_DIR;
            break;
        default:
            assert(false && "Shouldn't get here!");
            break;
    }

    // Log a message when VK_LAYER_PATH is set but the override layer paths take priority
    if (manifest_type == LOADER_DATA_FILE_MANIFEST_EXPLICIT_LAYER && NULL != override_env && NULL != path_override) {
        loader_log(inst, VULKAN_LOADER_INFO_BIT | VULKAN_LOADER_LAYER_BIT, 0,
                   "Ignoring VK_LAYER_PATH. The Override layer is active and has override paths set, which takes priority. "
                   "VK_LAYER_PATH is set to %s",
                   override_env);
    }

    if (path_override != NULL) {
        override_path = path_override;
    } else if (override_env != NULL) {
        override_path = override_env;
    }

    // Add two by default for NULL terminator and one path separator on end (just in case)
    search_path_size = 2;

    // If there's an override, use that (and the local folder if required) and nothing else
    if (NULL != override_path) {
        // Local folder and null terminator
        search_path_size += strlen(override_path) + 2;
    } else {
        // Add the size of any additional search paths defined in the additive environment variable
        if (NULL != additional_env) {
            search_path_size += determine_data_file_path_size(additional_env, 0) + 2;
#if defined(_WIN32)
        }
        if (NULL != package_path) {
            search_path_size += determine_data_file_path_size(package_path, 0) + 2;
        }
        if (search_path_size == 2) {
            goto out;
        }
#else  // !_WIN32
        }

        // Add the general search folders (with the appropriate relative folder added)
        rel_size = strlen(relative_location);
        if (rel_size > 0) {
#if defined(__APPLE__)
            search_path_size += MAXPATHLEN;
#endif
            // Only add the home folders if defined
            if (NULL != home_config_dir) {
                search_path_size += determine_data_file_path_size(home_config_dir, rel_size);
            }
            search_path_size += determine_data_file_path_size(xdg_config_dirs, rel_size);
            search_path_size += determine_data_file_path_size(SYSCONFDIR, rel_size);
#if defined(EXTRASYSCONFDIR)
            search_path_size += determine_data_file_path_size(EXTRASYSCONFDIR, rel_size);
#endif
            // Only add the home folders if defined
            if (NULL != home_data_dir) {
                search_path_size += determine_data_file_path_size(home_data_dir, rel_size);
            }
            search_path_size += determine_data_file_path_size(xdg_data_dirs, rel_size);
        }
#endif  // !_WIN32
    }

    // Allocate the required space
    search_path = loader_instance_heap_calloc(inst, search_path_size, VK_SYSTEM_ALLOCATION_SCOPE_COMMAND);
    if (NULL == search_path) {
        loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                   "read_data_files_in_search_paths: Failed to allocate space for search path of length %d",
                   (uint32_t)search_path_size);
        vk_result = VK_ERROR_OUT_OF_HOST_MEMORY;
        goto out;
    }

    cur_path_ptr = search_path;

    // Add the remaining paths to the list
    if (NULL != override_path) {
        strcpy(cur_path_ptr, override_path);
        cur_path_ptr += strlen(override_path);
    } else {
        // Add any additional search paths defined in the additive environment variable
        if (NULL != additional_env) {
            copy_data_file_info(additional_env, NULL, 0, &cur_path_ptr);
        }

#if defined(_WIN32)
        if (NULL != package_path) {
            copy_data_file_info(package_path, NULL, 0, &cur_path_ptr);
        }
#else
        if (rel_size > 0) {
#if defined(__APPLE__)
            // Add the bundle's Resources dir to the beginning of the search path.
            // Looks for manifests in the bundle first, before any system directories.
            CFBundleRef main_bundle = CFBundleGetMainBundle();
            if (NULL != main_bundle) {
                CFURLRef ref = CFBundleCopyResourcesDirectoryURL(main_bundle);
                if (NULL != ref) {
                    if (CFURLGetFileSystemRepresentation(ref, TRUE, (UInt8 *)cur_path_ptr, search_path_size)) {
                        cur_path_ptr += strlen(cur_path_ptr);
                        *cur_path_ptr++ = DIRECTORY_SYMBOL;
                        memcpy(cur_path_ptr, relative_location, rel_size);
                        cur_path_ptr += rel_size;
                        *cur_path_ptr++ = PATH_SEPARATOR;
                        if (manifest_type == LOADER_DATA_FILE_MANIFEST_DRIVER) {
                            use_first_found_manifest = true;
                        }
                    }
                    CFRelease(ref);
                }
            }
#endif  // __APPLE__

            // Only add the home folders if not NULL
            if (NULL != home_config_dir) {
                copy_data_file_info(home_config_dir, relative_location, rel_size, &cur_path_ptr);
            }
            copy_data_file_info(xdg_config_dirs, relative_location, rel_size, &cur_path_ptr);
            copy_data_file_info(SYSCONFDIR, relative_location, rel_size, &cur_path_ptr);
#if defined(EXTRASYSCONFDIR)
            copy_data_file_info(EXTRASYSCONFDIR, relative_location, rel_size, &cur_path_ptr);
#endif

            // Only add the home folders if not NULL
            if (NULL != home_data_dir) {
                copy_data_file_info(home_data_dir, relative_location, rel_size, &cur_path_ptr);
            }
            copy_data_file_info(xdg_data_dirs, relative_location, rel_size, &cur_path_ptr);
        }

        // Remove the last path separator
        --cur_path_ptr;

        assert(cur_path_ptr - search_path < (ptrdiff_t)search_path_size);
        *cur_path_ptr = '\0';
#endif  // !_WIN32
    }

    // Remove duplicate paths, or it would result in duplicate extensions, duplicate devices, etc.
    // This uses minimal memory, but is O(N^2) on the number of paths. Expect only a few paths.
    char path_sep_str[2] = {PATH_SEPARATOR, '\0'};
    size_t search_path_updated_size = strlen(search_path);
    for (size_t first = 0; first < search_path_updated_size;) {
        // If this is an empty path, erase it
        if (search_path[first] == PATH_SEPARATOR) {
            memmove(&search_path[first], &search_path[first + 1], search_path_updated_size - first + 1);
            search_path_updated_size -= 1;
            continue;
        }

        size_t first_end = first + 1;
        first_end += strcspn(&search_path[first_end], path_sep_str);
        for (size_t second = first_end + 1; second < search_path_updated_size;) {
            size_t second_end = second + 1;
            second_end += strcspn(&search_path[second_end], path_sep_str);
            if (first_end - first == second_end - second &&
                !strncmp(&search_path[first], &search_path[second], second_end - second)) {
                // Found duplicate. Include PATH_SEPARATOR in second_end, then erase it from search_path.
                if (search_path[second_end] == PATH_SEPARATOR) {
                    second_end++;
                }
                memmove(&search_path[second], &search_path[second_end], search_path_updated_size - second_end + 1);
                search_path_updated_size -= second_end - second;
            } else {
                second = second_end + 1;
            }
        }
        first = first_end + 1;
    }
    search_path_size = search_path_updated_size;

    // Print out the paths being searched if debugging is enabled
    uint32_t log_flags = 0;
    if (search_path_size > 0) {
        char *tmp_search_path = loader_instance_heap_alloc(inst, search_path_size + 1, VK_SYSTEM_ALLOCATION_SCOPE_COMMAND);
        if (NULL != tmp_search_path) {
            strncpy(tmp_search_path, search_path, search_path_size);
            tmp_search_path[search_path_size] = '\0';
            if (manifest_type == LOADER_DATA_FILE_MANIFEST_DRIVER) {
                log_flags = VULKAN_LOADER_DRIVER_BIT;
                loader_log(inst, VULKAN_LOADER_DRIVER_BIT, 0, "Searching for driver manifest files");
            } else {
                log_flags = VULKAN_LOADER_LAYER_BIT;
                loader_log(inst, VULKAN_LOADER_LAYER_BIT, 0, "Searching for layer manifest files");
            }
            loader_log(inst, log_flags, 0, "   In following locations:");
            char *cur_file;
            char *next_file = tmp_search_path;
            while (NULL != next_file && *next_file != '\0') {
                cur_file = next_file;
                next_file = loader_get_next_path(cur_file);
                loader_log(inst, log_flags, 0, "      %s", cur_file);
            }
            loader_instance_heap_free(inst, tmp_search_path);
        }
    }

    // Now, parse the paths and add any manifest files found in them.
    vk_result = add_data_files(inst, search_path, out_files, use_first_found_manifest);

    if (log_flags != 0 && out_files->count > 0) {
        loader_log(inst, log_flags, 0, "   Found the following files:");
        for (uint32_t cur_file = 0; cur_file < out_files->count; ++cur_file) {
            loader_log(inst, log_flags, 0, "      %s", out_files->filename_list[cur_file]);
        }
    } else {
        loader_log(inst, log_flags, 0, "   Found no files");
    }

    if (NULL != override_path) {
        *override_active = true;
    } else {
        *override_active = false;
    }

out:

    loader_free_getenv(additional_env, inst);
    loader_free_getenv(override_env, inst);
#if defined(_WIN32)
    loader_instance_heap_free(inst, package_path);
#else
    loader_free_getenv(xdg_config_home, inst);
    loader_free_getenv(xdg_config_dirs, inst);
    loader_free_getenv(xdg_data_home, inst);
    loader_free_getenv(xdg_data_dirs, inst);
    loader_free_getenv(xdg_data_home, inst);
    loader_free_getenv(home, inst);
    loader_instance_heap_free(inst, default_data_home);
    loader_instance_heap_free(inst, default_config_home);
#endif

    loader_instance_heap_free(inst, search_path);

    return vk_result;
}

// Find the Vulkan library manifest files.
//
// This function scans the appropriate locations for a list of JSON manifest files based on the
// "manifest_type".  The location is interpreted as Registry path on Windows and a directory path(s)
// on Linux.
// "home_location" is an additional directory in the users home directory to look at. It is
// expanded into the dir path $XDG_DATA_HOME/home_location or $HOME/.local/share/home_location
// depending on environment variables. This "home_location" is only used on Linux.
//
// \returns
// VKResult
// A string list of manifest files to be opened in out_files param.
// List has a pointer to string for each manifest filename.
// When done using the list in out_files, pointers should be freed.
// Location or override  string lists can be either files or directories as
// follows:
//            | location | override
// --------------------------------
// Win ICD    | files    | files
// Win Layer  | files    | dirs
// Linux ICD  | dirs     | files
// Linux Layer| dirs     | dirs

VkResult loader_get_data_files(const struct loader_instance *inst, enum loader_data_files_type manifest_type,
                               const char *path_override, struct loader_data_files *out_files) {
    VkResult res = VK_SUCCESS;
    bool override_active = false;

    // Free and init the out_files information so there's no false data left from uninitialized variables.
    if (out_files->filename_list != NULL) {
        for (uint32_t i = 0; i < out_files->count; i++) {
            if (NULL != out_files->filename_list[i]) {
                loader_instance_heap_free(inst, out_files->filename_list[i]);
                out_files->filename_list[i] = NULL;
            }
        }
        loader_instance_heap_free(inst, out_files->filename_list);
    }
    out_files->count = 0;
    out_files->alloc_count = 0;
    out_files->filename_list = NULL;

    res = read_data_files_in_search_paths(inst, manifest_type, path_override, &override_active, out_files);
    if (VK_SUCCESS != res) {
        goto out;
    }

#ifdef _WIN32
    // Read the registry if the override wasn't active.
    if (!override_active) {
        bool warn_if_not_present = false;
        char *registry_location = NULL;

        switch (manifest_type) {
            default:
                goto out;
            case LOADER_DATA_FILE_MANIFEST_DRIVER:
                warn_if_not_present = true;
                registry_location = VK_DRIVERS_INFO_REGISTRY_LOC;
                break;
            case LOADER_DATA_FILE_MANIFEST_IMPLICIT_LAYER:
                registry_location = VK_ILAYERS_INFO_REGISTRY_LOC;
                break;
            case LOADER_DATA_FILE_MANIFEST_EXPLICIT_LAYER:
                warn_if_not_present = true;
                registry_location = VK_ELAYERS_INFO_REGISTRY_LOC;
                break;
        }
        VkResult tmp_res =
            windows_read_data_files_in_registry(inst, manifest_type, warn_if_not_present, registry_location, out_files);
        // Only return an error if there was an error this time, and no manifest files from before.
        if (VK_SUCCESS != tmp_res && out_files->count == 0) {
            res = tmp_res;
            goto out;
        }
    }
#endif

out:

    if (VK_SUCCESS != res && NULL != out_files->filename_list) {
        for (uint32_t remove = 0; remove < out_files->count; remove++) {
            loader_instance_heap_free(inst, out_files->filename_list[remove]);
        }
        loader_instance_heap_free(inst, out_files->filename_list);
        out_files->count = 0;
        out_files->alloc_count = 0;
        out_files->filename_list = NULL;
    }

    return res;
}

struct ICDManifestInfo {
    char full_library_path[MAX_STRING_SIZE];
    uint32_t version;
};

// Takes a json file, opens, reads, and parses an ICD Manifest out of it.
// Should only return VK_SUCCESS, VK_ERROR_INCOMPATIBLE_DRIVER, or VK_ERROR_OUT_OF_HOST_MEMORY
VkResult loader_parse_icd_manifest(const struct loader_instance *inst, char *file_str, struct ICDManifestInfo *icd,
                                   bool *skipped_portability_drivers) {
    VkResult res = VK_SUCCESS;
    cJSON *json = NULL;
    cJSON *item = NULL, *itemICD = NULL;

    char *file_vers_str = NULL;
    char *library_path = NULL;
    char *library_arch_str = NULL;
    char *version_str = NULL;

    if (file_str == NULL) {
        goto out;
    }

    res = loader_get_json(inst, file_str, &json);
    if (res == VK_ERROR_OUT_OF_HOST_MEMORY) {
        goto out;
    }
    if (res != VK_SUCCESS || NULL == json) {
        res = VK_ERROR_INCOMPATIBLE_DRIVER;
        goto out;
    }

    item = cJSON_GetObjectItem(json, "file_format_version");
    if (item == NULL) {
        loader_log(inst, VULKAN_LOADER_WARN_BIT | VULKAN_LOADER_DRIVER_BIT, 0,
                   "loader_parse_icd_manifest: ICD JSON %s does not have a \'file_format_version\' field. Skipping ICD JSON.",
                   file_str);
        res = VK_ERROR_INCOMPATIBLE_DRIVER;
        goto out;
    }

    file_vers_str = cJSON_Print(item);
    if (NULL == file_vers_str) {
        // Only reason the print can fail is if there was an allocation issue
        loader_log(inst, VULKAN_LOADER_WARN_BIT | VULKAN_LOADER_DRIVER_BIT, 0,
                   "loader_parse_icd_manifest: Failed retrieving ICD JSON %s \'file_format_version\' field. Skipping ICD JSON",
                   file_str);
        res = VK_ERROR_OUT_OF_HOST_MEMORY;
        goto out;
    }
    loader_log(inst, VULKAN_LOADER_DRIVER_BIT, 0, "Found ICD manifest file %s, version %s", file_str, file_vers_str);

    // Get the version of the driver manifest
    loader_api_version json_file_version = loader_make_full_version(loader_parse_version_string(file_vers_str));

    // Loader only knows versions 1.0.0 and 1.0.1, anything above it is unknown
    if (loader_check_version_meets_required(loader_combine_version(1, 0, 2), json_file_version)) {
        loader_log(inst, VULKAN_LOADER_INFO_BIT | VULKAN_LOADER_DRIVER_BIT, 0,
                   "loader_parse_icd_manifest: %s has unknown icd manifest file version %d.%d.%d. May cause errors.", file_str,
                   json_file_version.major, json_file_version.minor, json_file_version.patch);
    }

    itemICD = cJSON_GetObjectItem(json, "ICD");
    if (itemICD == NULL) {
        loader_log(inst, VULKAN_LOADER_WARN_BIT | VULKAN_LOADER_DRIVER_BIT, 0,
                   "loader_parse_icd_manifest: Can not find \'ICD\' object in ICD JSON file %s. Skipping ICD JSON", file_str);
        res = VK_ERROR_INCOMPATIBLE_DRIVER;
        goto out;
    }

    item = cJSON_GetObjectItem(itemICD, "library_path");
    if (item == NULL) {
        loader_log(inst, VULKAN_LOADER_WARN_BIT | VULKAN_LOADER_DRIVER_BIT, 0,
                   "loader_parse_icd_manifest: Failed to find \'library_path\' object in ICD JSON file %s. Skipping ICD JSON.",
                   file_str);
        res = VK_ERROR_INCOMPATIBLE_DRIVER;
        goto out;
    }
    library_path = cJSON_Print(item);
    if (!library_path || strlen(library_path) == 0) {
        loader_log(inst, VULKAN_LOADER_WARN_BIT | VULKAN_LOADER_DRIVER_BIT, 0,
                   "loader_parse_icd_manifest: Failed retrieving ICD JSON %s \'library_path\' field. Skipping ICD JSON.", file_str);
        res = VK_ERROR_OUT_OF_HOST_MEMORY;
        goto out;
    }
    size_t library_path_len = strlen(library_path);
    // cJSON prints everything with quotes so they need to be removed.
    // move every char forward one, so the leading quote is replaced.
    memmove(library_path, &library_path[1], library_path_len - 2);
    // replace end quote with null terminator
    library_path[library_path_len - 2] = '\0';

    if (strlen(library_path) == 0) {
        loader_log(inst, VULKAN_LOADER_WARN_BIT | VULKAN_LOADER_DRIVER_BIT, 0,
                   "loader_parse_icd_manifest: ICD JSON %s \'library_path\' field is empty. Skipping ICD JSON.", file_str);
        res = VK_ERROR_INCOMPATIBLE_DRIVER;
        goto out;
    }

    // Print out the paths being searched if debugging is enabled
    loader_log(inst, VULKAN_LOADER_DEBUG_BIT | VULKAN_LOADER_DRIVER_BIT, 0, "Searching for ICD drivers named %s", library_path);
    if (loader_platform_is_path(library_path)) {
        // a relative or absolute path
        char *name_copy = loader_stack_alloc(strlen(file_str) + 1);
        char *rel_base;
        strcpy(name_copy, file_str);
        rel_base = loader_platform_dirname(name_copy);
        loader_expand_path(library_path, rel_base, MAX_STRING_SIZE, &icd->full_library_path[0]);
    } else {
// a filename which is assumed in a system directory
#if defined(DEFAULT_VK_DRIVERS_PATH)
        loader_get_fullpath(library_path, DEFAULT_VK_DRIVERS_PATH, MAX_STRING_SIZE, &icd->full_library_path[0]);
#else
        loader_get_fullpath(library_path, "", MAX_STRING_SIZE, &icd->full_library_path[0]);
#endif
    }

    item = cJSON_GetObjectItem(itemICD, "api_version");
    if (item == NULL) {
        loader_log(inst, VULKAN_LOADER_WARN_BIT | VULKAN_LOADER_DRIVER_BIT, 0,
                   "loader_parse_icd_manifest: ICD JSON %s does not have an \'api_version\' field. Skipping ICD JSON.", file_str);
        res = VK_ERROR_INCOMPATIBLE_DRIVER;
        goto out;
    }
    version_str = cJSON_Print(item);
    if (NULL == version_str) {
        // Only reason the print can fail is if there was an allocation issue
        loader_log(inst, VULKAN_LOADER_WARN_BIT | VULKAN_LOADER_DRIVER_BIT, 0,
                   "loader_parse_icd_manifest: Failed retrieving ICD JSON %s \'api_version\' field. Skipping ICD JSON.", file_str);

        res = VK_ERROR_OUT_OF_HOST_MEMORY;
        goto out;
    }
    icd->version = loader_parse_version_string(version_str);

    if (VK_API_VERSION_VARIANT(icd->version) != 0) {
        loader_log(inst, VULKAN_LOADER_INFO_BIT | VULKAN_LOADER_DRIVER_BIT, 0,
                   "loader_parse_icd_manifest: Driver's ICD JSON %s \'api_version\' field contains a non-zero variant value of %d. "
                   " Skipping ICD JSON.",
                   file_str, VK_API_VERSION_VARIANT(icd->version));
        res = VK_ERROR_INCOMPATIBLE_DRIVER;
        goto out;
    }

    // Skip over ICD's which contain a true "is_portability_driver" value whenever the application doesn't enable
    // portability enumeration.
    item = cJSON_GetObjectItem(itemICD, "is_portability_driver");
    if (item != NULL && item->type == cJSON_True && inst && !inst->portability_enumeration_enabled) {
        if (skipped_portability_drivers) {
            *skipped_portability_drivers = true;
        }
        res = VK_ERROR_INCOMPATIBLE_DRIVER;
        goto out;
    }

    item = cJSON_GetObjectItem(itemICD, "library_arch");
    if (item != NULL) {
        library_arch_str = cJSON_Print(item);
        if (NULL != library_arch_str) {
            // cJSON includes the quotes by default, so we need to look for those here
            if ((strncmp(library_arch_str, "\"32\"", 4) == 0 && sizeof(void *) != 4) ||
                (strncmp(library_arch_str, "\"64\"", 4) == 0 && sizeof(void *) != 8)) {
                loader_log(inst, VULKAN_LOADER_INFO_BIT, 0,
                           "loader_parse_icd_manifest: Driver library architecture doesn't match the current running "
                           "architecture, skipping this driver");
                res = VK_ERROR_INCOMPATIBLE_DRIVER;
                goto out;
            }
        } else {
            res = VK_ERROR_OUT_OF_HOST_MEMORY;
            goto out;
        }
    }
out:
    cJSON_Delete(json);
    loader_instance_heap_free(inst, file_vers_str);
    loader_instance_heap_free(inst, library_path);
    loader_instance_heap_free(inst, version_str);
    loader_instance_heap_free(inst, library_arch_str);
    return res;
}

// Try to find the Vulkan ICD driver(s).
//
// This function scans the default system loader path(s) or path specified by either the
// VK_DRIVER_FILES or VK_ICD_FILENAMES environment variable in order to find loadable
// VK ICDs manifest files.
// From these manifest files it finds the ICD libraries.
//
// skipped_portability_drivers is used to report whether the loader found drivers which report
// portability but the application didn't enable the bit to enumerate them
// Can be NULL
//
// \returns
// Vulkan result
// (on result == VK_SUCCESS) a list of icds that were discovered
VkResult loader_icd_scan(const struct loader_instance *inst, struct loader_icd_tramp_list *icd_tramp_list,
                         const VkInstanceCreateInfo *pCreateInfo, bool *skipped_portability_drivers) {
    struct loader_data_files manifest_files;
    VkResult res = VK_SUCCESS;
    bool lockedMutex = false;
    struct loader_envvar_filter select_filter;
    struct loader_envvar_filter disable_filter;

    // Before we begin anything, init manifest_files to avoid a delete of garbage memory if
    // a failure occurs before allocating the manifest filename_list.
    memset(&manifest_files, 0, sizeof(struct loader_data_files));

    // Set up the ICD Trampoline list so elements can be written into it.
    res = loader_scanned_icd_init(inst, icd_tramp_list);
    if (res == VK_ERROR_OUT_OF_HOST_MEMORY) {
        return res;
    }

    bool direct_driver_loading_exclusive_mode = false;
    res = loader_scan_for_direct_drivers(inst, pCreateInfo, icd_tramp_list, &direct_driver_loading_exclusive_mode);
    if (res == VK_ERROR_OUT_OF_HOST_MEMORY) {
        goto out;
    }
    if (direct_driver_loading_exclusive_mode) {
        // Make sure to jump over the system & env-var driver discovery mechanisms if exclusive mode is set, even if no drivers
        // were successfully found through the direct driver loading mechanism
        goto out;
    }

    // Parse the filter environment variables to determine if we have any special behavior
    res = parse_generic_filter_environment_var(inst, VK_DRIVERS_SELECT_ENV_VAR, &select_filter);
    if (VK_SUCCESS != res) {
        goto out;
    }
    res = parse_generic_filter_environment_var(inst, VK_DRIVERS_DISABLE_ENV_VAR, &disable_filter);
    if (VK_SUCCESS != res) {
        goto out;
    }

    // Get a list of manifest files for ICDs
    res = loader_get_data_files(inst, LOADER_DATA_FILE_MANIFEST_DRIVER, NULL, &manifest_files);
    if (VK_SUCCESS != res) {
        goto out;
    }

    loader_platform_thread_lock_mutex(&loader_json_lock);
    lockedMutex = true;
    for (uint32_t i = 0; i < manifest_files.count; i++) {
        VkResult icd_res = VK_SUCCESS;
        struct ICDManifestInfo icd;
        memset(&icd, 0, sizeof(struct ICDManifestInfo));
        icd_res = loader_parse_icd_manifest(inst, manifest_files.filename_list[i], &icd, skipped_portability_drivers);
        if (VK_ERROR_OUT_OF_HOST_MEMORY == icd_res) {
            res = icd_res;
            goto out;
        } else if (VK_ERROR_INCOMPATIBLE_DRIVER == icd_res) {
            continue;
        }

        if (select_filter.count > 0 || disable_filter.count > 0) {
            // Get only the filename for comparing to the filters
            char *just_filename_str = strrchr(manifest_files.filename_list[i], DIRECTORY_SYMBOL);

            // No directory symbol, just the filename
            if (NULL == just_filename_str) {
                just_filename_str = manifest_files.filename_list[i];
            } else {
                just_filename_str++;
            }

            bool name_matches_select =
                (select_filter.count > 0 && check_name_matches_filter_environment_var(inst, just_filename_str, &select_filter));
            bool name_matches_disable =
                (disable_filter.count > 0 && check_name_matches_filter_environment_var(inst, just_filename_str, &disable_filter));

            if (name_matches_disable && !name_matches_select) {
                loader_log(inst, VULKAN_LOADER_WARN_BIT | VULKAN_LOADER_DRIVER_BIT, 0,
                           "Driver \"%s\" ignored because it was disabled by env var \'%s\'", just_filename_str,
                           VK_DRIVERS_DISABLE_ENV_VAR);
                continue;
            }
            if (select_filter.count != 0 && !name_matches_select) {
                loader_log(inst, VULKAN_LOADER_WARN_BIT | VULKAN_LOADER_DRIVER_BIT, 0,
                           "Driver \"%s\" ignored because not selected by env var \'%s\'", just_filename_str,
                           VK_DRIVERS_SELECT_ENV_VAR);
                continue;
            }
        }

        enum loader_layer_library_status lib_status;
        icd_res = loader_scanned_icd_add(inst, icd_tramp_list, icd.full_library_path, icd.version, &lib_status);
        if (VK_ERROR_OUT_OF_HOST_MEMORY == icd_res) {
            res = icd_res;
            goto out;
        } else if (VK_ERROR_INCOMPATIBLE_DRIVER == icd_res) {
            switch (lib_status) {
                case LOADER_LAYER_LIB_NOT_LOADED:
                case LOADER_LAYER_LIB_ERROR_FAILED_TO_LOAD:
                    loader_log(inst, VULKAN_LOADER_ERROR_BIT | VULKAN_LOADER_DRIVER_BIT, 0,
                               "loader_icd_scan: Failed loading library associated with ICD JSON %s. Ignoring this JSON",
                               icd.full_library_path);
                    break;
                case LOADER_LAYER_LIB_ERROR_WRONG_BIT_TYPE: {
                    loader_log(inst, VULKAN_LOADER_DRIVER_BIT, 0, "Requested layer %s was wrong bit-type. Ignoring this JSON",
                               icd.full_library_path);
                    break;
                }
                case LOADER_LAYER_LIB_SUCCESS_LOADED:
                case LOADER_LAYER_LIB_ERROR_OUT_OF_MEMORY:
                    // Shouldn't be able to reach this but if it is, best to report a debug
                    loader_log(inst, VULKAN_LOADER_WARN_BIT | VULKAN_LOADER_DRIVER_BIT, 0,
                               "Shouldn't reach this. A valid version of requested ICD %s was loaded but something bad "
                               "happened afterwards.",
                               icd.full_library_path);
                    break;
            }
        }
    }

out:
    if (NULL != manifest_files.filename_list) {
        for (uint32_t i = 0; i < manifest_files.count; i++) {
            loader_instance_heap_free(inst, manifest_files.filename_list[i]);
        }
        loader_instance_heap_free(inst, manifest_files.filename_list);
    }
    if (lockedMutex) {
        loader_platform_thread_unlock_mutex(&loader_json_lock);
    }

    return res;
}

VkResult loader_scan_for_layers(struct loader_instance *inst, struct loader_layer_list *instance_layers) {
    VkResult res = VK_SUCCESS;
    char *file_str;
    struct loader_data_files manifest_files;
    cJSON *json = NULL;
    bool override_layer_valid = false;
    char *override_paths = NULL;
    uint32_t total_count = 0;
    struct loader_envvar_filter enable_filter;
    struct loader_envvar_disable_layers_filter disable_filter;

    // Before we begin anything, init manifest_files to avoid a delete of garbage memory if
    // a failure occurs before allocating the manifest filename_list.
    memset(&manifest_files, 0, sizeof(struct loader_data_files));

    // Parse the filter environment variables to determine if we have any special behavior
    res = parse_generic_filter_environment_var(NULL, VK_LAYERS_ENABLE_ENV_VAR, &enable_filter);
    if (VK_SUCCESS != res) {
        goto out;
    }
    res = parse_layers_disable_filter_environment_var(NULL, &disable_filter);
    if (VK_SUCCESS != res) {
        goto out;
    }

    // Cleanup any previously scanned libraries
    loader_delete_layer_list_and_properties(inst, instance_layers);

    loader_platform_thread_lock_mutex(&loader_json_lock);

    // Get a list of manifest files for any implicit layers
    res = loader_get_data_files(inst, LOADER_DATA_FILE_MANIFEST_IMPLICIT_LAYER, NULL, &manifest_files);
    if (VK_SUCCESS != res) {
        goto out;
    }

    if (manifest_files.count != 0) {
        total_count += manifest_files.count;
        for (uint32_t i = 0; i < manifest_files.count; i++) {
            file_str = manifest_files.filename_list[i];
            if (file_str == NULL) {
                continue;
            }

            // Parse file into JSON struct
            VkResult local_res = loader_get_json(inst, file_str, &json);
            if (VK_ERROR_OUT_OF_HOST_MEMORY == local_res) {
                res = VK_ERROR_OUT_OF_HOST_MEMORY;
                goto out;
            } else if (VK_SUCCESS != local_res || NULL == json) {
                continue;
            }

            local_res = loader_add_layer_properties(inst, instance_layers, json, true, file_str);
            cJSON_Delete(json);

            // If the error is anything other than out of memory we still want to try to load the other layers
            if (VK_ERROR_OUT_OF_HOST_MEMORY == local_res) {
                res = VK_ERROR_OUT_OF_HOST_MEMORY;
                goto out;
            }
        }
    }

    // Remove any extraneous override layers.
    remove_all_non_valid_override_layers(inst, instance_layers);

    // Check to see if the override layer is present, and use it's override paths.
    for (int32_t i = 0; i < (int32_t)instance_layers->count; i++) {
        struct loader_layer_properties *prop = &instance_layers->list[i];
        if (prop->is_override && loader_implicit_layer_is_enabled(inst, &enable_filter, &disable_filter, prop) &&
            prop->num_override_paths > 0) {
            char *cur_write_ptr = NULL;
            size_t override_path_size = 0;
            for (uint32_t j = 0; j < prop->num_override_paths; j++) {
                override_path_size += determine_data_file_path_size(prop->override_paths[j], 0);
            }
            override_paths = loader_instance_heap_alloc(inst, override_path_size, VK_SYSTEM_ALLOCATION_SCOPE_COMMAND);
            if (override_paths == NULL) {
                res = VK_ERROR_OUT_OF_HOST_MEMORY;
                goto out;
            }
            cur_write_ptr = &override_paths[0];
            for (uint32_t j = 0; j < prop->num_override_paths; j++) {
                copy_data_file_info(prop->override_paths[j], NULL, 0, &cur_write_ptr);
            }
            // Remove the last path separator
            --cur_write_ptr;
            assert(cur_write_ptr - override_paths < (ptrdiff_t)override_path_size);
            *cur_write_ptr = '\0';
            loader_log(NULL, VULKAN_LOADER_WARN_BIT | VULKAN_LOADER_LAYER_BIT, 0, "Override layer has override paths set to %s",
                       override_paths);
        }
    }

    // Get a list of manifest files for explicit layers
    res = loader_get_data_files(inst, LOADER_DATA_FILE_MANIFEST_EXPLICIT_LAYER, override_paths, &manifest_files);
    if (VK_SUCCESS != res) {
        goto out;
    }

    // Make sure we have at least one layer, if not, go ahead and return
    if (manifest_files.count == 0 && total_count == 0) {
        goto out;
    } else {
        for (uint32_t i = 0; i < manifest_files.count; i++) {
            file_str = manifest_files.filename_list[i];
            if (file_str == NULL) {
                continue;
            }

            // Parse file into JSON struct
            VkResult local_res = loader_get_json(inst, file_str, &json);
            if (VK_ERROR_OUT_OF_HOST_MEMORY == local_res) {
                res = VK_ERROR_OUT_OF_HOST_MEMORY;
                goto out;
            } else if (VK_SUCCESS != local_res || NULL == json) {
                continue;
            }

            local_res = loader_add_layer_properties(inst, instance_layers, json, false, file_str);
            cJSON_Delete(json);

            // If the error is anything other than out of memory we still want to try to load the other layers
            if (VK_ERROR_OUT_OF_HOST_MEMORY == local_res) {
                res = local_res;
                goto out;
            }
        }
    }

    // Verify any meta-layers in the list are valid and all the component layers are
    // actually present in the available layer list
    verify_all_meta_layers(inst, &enable_filter, &disable_filter, instance_layers, &override_layer_valid);

    if (override_layer_valid) {
        loader_remove_layers_in_blacklist(inst, instance_layers);
        if (NULL != inst) {
            inst->override_layer_present = true;
        }
    }

    // Remove disabled layers
    for (uint32_t i = 0; i < instance_layers->count; ++i) {
        if (!loader_layer_is_available(inst, &enable_filter, &disable_filter, &instance_layers->list[i])) {
            loader_remove_layer_in_list(inst, instance_layers, i);
            i--;
        }
    }

out:

    loader_instance_heap_free(inst, override_paths);
    if (NULL != manifest_files.filename_list) {
        for (uint32_t i = 0; i < manifest_files.count; i++) {
            loader_instance_heap_free(inst, manifest_files.filename_list[i]);
        }
        loader_instance_heap_free(inst, manifest_files.filename_list);
    }
    loader_platform_thread_unlock_mutex(&loader_json_lock);
    return res;
}

VkResult loader_scan_for_implicit_layers(struct loader_instance *inst, struct loader_layer_list *instance_layers,
                                         loader_platform_dl_handle **libs) {
    struct loader_envvar_filter enable_filter;
    struct loader_envvar_disable_layers_filter disable_filter;
    char *file_str;
    struct loader_data_files manifest_files;
    cJSON *json = NULL;
    bool override_layer_valid = false;
    char *override_paths = NULL;
    bool implicit_metalayer_present = false;
    bool have_json_lock = false;
    VkResult res = VK_SUCCESS;

    // Before we begin anything, init manifest_files to avoid a delete of garbage memory if
    // a failure occurs before allocating the manifest filename_list.
    memset(&manifest_files, 0, sizeof(struct loader_data_files));

    // Parse the filter environment variables to determine if we have any special behavior
    res = parse_generic_filter_environment_var(inst, VK_LAYERS_ENABLE_ENV_VAR, &enable_filter);
    if (VK_SUCCESS != res) {
        goto out;
    }
    res = parse_layers_disable_filter_environment_var(inst, &disable_filter);
    if (VK_SUCCESS != res) {
        goto out;
    }

    res = loader_get_data_files(inst, LOADER_DATA_FILE_MANIFEST_IMPLICIT_LAYER, NULL, &manifest_files);
    if (VK_SUCCESS != res || manifest_files.count == 0) {
        goto out;
    }

    // Cleanup any previously scanned libraries
    loader_delete_layer_list_and_properties(inst, instance_layers);

    loader_platform_thread_lock_mutex(&loader_json_lock);
    have_json_lock = true;

    for (uint32_t i = 0; i < manifest_files.count; i++) {
        file_str = manifest_files.filename_list[i];
        if (file_str == NULL) {
            continue;
        }

        // parse file into JSON struct
        VkResult temp_res = loader_get_json(inst, file_str, &json);
        if (VK_ERROR_OUT_OF_HOST_MEMORY == temp_res) {
            res = temp_res;
            goto out;
        } else if (VK_SUCCESS != temp_res || NULL == json) {
            continue;
        }

        temp_res = loader_add_layer_properties(inst, instance_layers, json, true, file_str);

        loader_instance_heap_free(inst, file_str);
        manifest_files.filename_list[i] = NULL;
        cJSON_Delete(json);

        if (VK_ERROR_OUT_OF_HOST_MEMORY == temp_res) {
            res = temp_res;
            goto out;
        }
    }

    // Remove any extraneous override layers.
    remove_all_non_valid_override_layers(inst, instance_layers);

    // Check to see if either the override layer is present, or another implicit meta-layer.
    // Each of these may require explicit layers to be enabled at this time.
    for (int32_t i = 0; i < (int32_t)instance_layers->count; i++) {
        struct loader_layer_properties *prop = &instance_layers->list[i];
        if (prop->is_override && loader_implicit_layer_is_enabled(inst, &enable_filter, &disable_filter, prop)) {
            override_layer_valid = true;
            if (prop->num_override_paths > 0) {
                char *cur_write_ptr = NULL;
                size_t override_path_size = 0;
                for (uint32_t j = 0; j < prop->num_override_paths; j++) {
                    override_path_size += determine_data_file_path_size(prop->override_paths[j], 0);
                }
                override_paths = loader_instance_heap_alloc(inst, override_path_size, VK_SYSTEM_ALLOCATION_SCOPE_COMMAND);
                if (override_paths == NULL) {
                    goto out;
                }
                cur_write_ptr = &override_paths[0];
                for (uint32_t j = 0; j < prop->num_override_paths; j++) {
                    copy_data_file_info(prop->override_paths[j], NULL, 0, &cur_write_ptr);
                }
                // Remove the last path separator
                --cur_write_ptr;
                assert(cur_write_ptr - override_paths < (ptrdiff_t)override_path_size);
                *cur_write_ptr = '\0';
                loader_log(NULL, VULKAN_LOADER_WARN_BIT | VULKAN_LOADER_LAYER_BIT, 0, "Override layer has override paths set to %s",
                           override_paths);
            }
        } else if (!prop->is_override && prop->type_flags & VK_LAYER_TYPE_FLAG_META_LAYER) {
            implicit_metalayer_present = true;
        }
    }

    // If either the override layer or an implicit meta-layer are present, we need to add
    // explicit layer info as well.  Not to worry, though, all explicit layers not included
    // in the override layer will be removed below in loader_remove_layers_in_blacklist().
    if (override_layer_valid || implicit_metalayer_present) {
        if (VK_SUCCESS != loader_get_data_files(inst, LOADER_DATA_FILE_MANIFEST_EXPLICIT_LAYER, override_paths, &manifest_files)) {
            goto out;
        }

        for (uint32_t i = 0; i < manifest_files.count; i++) {
            file_str = manifest_files.filename_list[i];
            if (file_str == NULL) {
                continue;
            }

            // parse file into JSON struct
            res = loader_get_json(inst, file_str, &json);
            if (VK_ERROR_OUT_OF_HOST_MEMORY == res) {
                goto out;
            } else if (VK_SUCCESS != res || NULL == json) {
                continue;
            }

            VkResult temp_res = loader_add_layer_properties(inst, instance_layers, json, false, file_str);
            loader_instance_heap_free(inst, file_str);
            manifest_files.filename_list[i] = NULL;
            cJSON_Delete(json);

            if (VK_ERROR_OUT_OF_HOST_MEMORY == temp_res) {
                res = temp_res;
                goto out;
            }
        }
    }

    // Verify any meta-layers in the list are valid and all the component layers are
    // actually present in the available layer list
    verify_all_meta_layers(inst, &enable_filter, &disable_filter, instance_layers, &override_layer_valid);

    if (override_layer_valid || implicit_metalayer_present) {
        loader_remove_layers_not_in_implicit_meta_layers(inst, instance_layers);
        if (override_layer_valid && inst != NULL) {
            inst->override_layer_present = true;
        }
    }

    // Remove disabled layers
    for (uint32_t i = 0; i < instance_layers->count; ++i) {
        if (!loader_implicit_layer_is_enabled(inst, &enable_filter, &disable_filter, &instance_layers->list[i])) {
            loader_remove_layer_in_list(inst, instance_layers, i);
            i--;
        }
    }

    // We'll need to save the dl handles so we can close them later
    if (instance_layers->count > 0 && NULL != libs) {
        *libs = loader_calloc(NULL, sizeof(loader_platform_dl_handle) * instance_layers->count, VK_SYSTEM_ALLOCATION_SCOPE_COMMAND);
        if (*libs == NULL) {
            res = VK_ERROR_OUT_OF_HOST_MEMORY;
            goto out;
        }
    }

out:

    loader_instance_heap_free(inst, override_paths);
    for (uint32_t i = 0; i < manifest_files.count; i++) {
        loader_instance_heap_free(inst, manifest_files.filename_list[i]);
    }
    loader_instance_heap_free(inst, manifest_files.filename_list);

    if (have_json_lock) {
        loader_platform_thread_unlock_mutex(&loader_json_lock);
    }

    return res;
}

static VKAPI_ATTR PFN_vkVoidFunction VKAPI_CALL loader_gpdpa_instance_terminator(VkInstance inst, const char *pName) {
    // inst is not wrapped
    if (inst == VK_NULL_HANDLE) {
        return NULL;
    }
    VkLayerInstanceDispatchTable *disp_table = *(VkLayerInstanceDispatchTable **)inst;
    void *addr;

    if (disp_table == NULL) return NULL;

    bool found_name;
    addr = loader_lookup_instance_dispatch_table(disp_table, pName, &found_name);
    if (found_name) {
        return addr;
    }

    // Check if any drivers support the function, and if so, add it to the unknown function list
    addr = loader_phys_dev_ext_gpa_term(loader_get_instance(inst), pName);
    if (NULL != addr) return addr;

    // Don't call down the chain, this would be an infinite loop
    loader_log(NULL, VULKAN_LOADER_DEBUG_BIT, 0, "loader_gpdpa_instance_terminator() unrecognized name %s", pName);
    return NULL;
}

static VKAPI_ATTR PFN_vkVoidFunction VKAPI_CALL loader_gpa_instance_terminator(VkInstance inst, const char *pName) {
    if (!strcmp(pName, "vkGetInstanceProcAddr")) {
        return (PFN_vkVoidFunction)loader_gpa_instance_terminator;
    }
    if (!strcmp(pName, "vk_layerGetPhysicalDeviceProcAddr")) {
        return (PFN_vkVoidFunction)loader_gpdpa_instance_terminator;
    }
    if (!strcmp(pName, "vkCreateInstance")) {
        return (PFN_vkVoidFunction)terminator_CreateInstance;
    }
    if (!strcmp(pName, "vkCreateDevice")) {
        return (PFN_vkVoidFunction)terminator_CreateDevice;
    }

    // The VK_EXT_debug_utils functions need a special case here so the terminators can still be found from
    // vkGetInstanceProcAddr This is because VK_EXT_debug_utils is an instance level extension with device level functions, and
    // is 'supported' by the loader. There needs to be a terminator in case a driver doesn't support VK_EXT_debug_utils.
    if (!strcmp(pName, "vkSetDebugUtilsObjectNameEXT")) {
        return (PFN_vkVoidFunction)terminator_SetDebugUtilsObjectNameEXT;
    }
    if (!strcmp(pName, "vkSetDebugUtilsObjectTagEXT")) {
        return (PFN_vkVoidFunction)terminator_SetDebugUtilsObjectTagEXT;
    }
    if (!strcmp(pName, "vkQueueBeginDebugUtilsLabelEXT")) {
        return (PFN_vkVoidFunction)terminator_QueueBeginDebugUtilsLabelEXT;
    }
    if (!strcmp(pName, "vkQueueEndDebugUtilsLabelEXT")) {
        return (PFN_vkVoidFunction)terminator_QueueEndDebugUtilsLabelEXT;
    }
    if (!strcmp(pName, "vkQueueInsertDebugUtilsLabelEXT")) {
        return (PFN_vkVoidFunction)terminator_QueueInsertDebugUtilsLabelEXT;
    }
    if (!strcmp(pName, "vkCmdBeginDebugUtilsLabelEXT")) {
        return (PFN_vkVoidFunction)terminator_CmdBeginDebugUtilsLabelEXT;
    }
    if (!strcmp(pName, "vkCmdEndDebugUtilsLabelEXT")) {
        return (PFN_vkVoidFunction)terminator_CmdEndDebugUtilsLabelEXT;
    }
    if (!strcmp(pName, "vkCmdInsertDebugUtilsLabelEXT")) {
        return (PFN_vkVoidFunction)terminator_CmdInsertDebugUtilsLabelEXT;
    }

    // inst is not wrapped
    if (inst == VK_NULL_HANDLE) {
        return NULL;
    }
    VkLayerInstanceDispatchTable *disp_table = *(VkLayerInstanceDispatchTable **)inst;
    void *addr;

    if (disp_table == NULL) return NULL;

    bool found_name;
    addr = loader_lookup_instance_dispatch_table(disp_table, pName, &found_name);
    if (found_name) {
        return addr;
    }

    // Check if it is an unknown physical device function, to see if any drivers support it.
    addr = loader_phys_dev_ext_gpa_term(loader_get_instance(inst), pName);
    if (addr) {
        return addr;
    }

    // Assume it is an unknown device function, check to see if any drivers support it.
    addr = loader_dev_ext_gpa_term(loader_get_instance(inst), pName);
    if (addr) {
        return addr;
    }

    // Don't call down the chain, this would be an infinite loop
    loader_log(NULL, VULKAN_LOADER_DEBUG_BIT, 0, "loader_gpa_instance_terminator() unrecognized name %s", pName);
    return NULL;
}

VKAPI_ATTR PFN_vkVoidFunction VKAPI_CALL loader_gpa_device_terminator(VkDevice device, const char *pName) {
    struct loader_device *dev;
    struct loader_icd_term *icd_term = loader_get_icd_and_device(device, &dev, NULL);

    // Return this function if a layer above here is asking for the vkGetDeviceProcAddr.
    // This is so we can properly intercept any device commands needing a terminator.
    if (!strcmp(pName, "vkGetDeviceProcAddr")) {
        return (PFN_vkVoidFunction)loader_gpa_device_terminator;
    }

    // NOTE: Device Funcs needing Trampoline/Terminator.
    // Overrides for device functions needing a trampoline and
    // a terminator because certain device entry-points still need to go
    // through a terminator before hitting the ICD.  This could be for
    // several reasons, but the main one is currently unwrapping an
    // object before passing the appropriate info along to the ICD.
    // This is why we also have to override the direct ICD call to
    // vkGetDeviceProcAddr to intercept those calls.
    // If the pName is for a 'known' function but isn't available, due to
    // the corresponding extension/feature not being enabled, we need to
    // return NULL and not call down to the driver's GetDeviceProcAddr.
    if (NULL != dev) {
        bool found_name = false;
        PFN_vkVoidFunction addr = get_extension_device_proc_terminator(dev, pName, &found_name);
        if (found_name) {
            return addr;
        }
    }

    return icd_term->dispatch.GetDeviceProcAddr(device, pName);
}

struct loader_instance *loader_get_instance(const VkInstance instance) {
    // look up the loader_instance in our list by comparing dispatch tables, as
    // there is no guarantee the instance is still a loader_instance* after any
    // layers which wrap the instance object.
    const VkLayerInstanceDispatchTable *disp;
    struct loader_instance *ptr_instance = (struct loader_instance *)instance;
    if (VK_NULL_HANDLE == instance || LOADER_MAGIC_NUMBER != ptr_instance->magic) {
        return NULL;
    } else {
        disp = loader_get_instance_layer_dispatch(instance);
        loader_platform_thread_lock_mutex(&loader_global_instance_list_lock);
        for (struct loader_instance *inst = loader.instances; inst; inst = inst->next) {
            if (&inst->disp->layer_inst_disp == disp) {
                ptr_instance = inst;
                break;
            }
        }
        loader_platform_thread_unlock_mutex(&loader_global_instance_list_lock);
    }
    return ptr_instance;
}

static loader_platform_dl_handle loader_open_layer_file(const struct loader_instance *inst, struct loader_layer_properties *prop) {
    if ((prop->lib_handle = loader_platform_open_library(prop->lib_name)) == NULL) {
        loader_handle_load_library_error(inst, prop->lib_name, &prop->lib_status);
    } else {
        prop->lib_status = LOADER_LAYER_LIB_SUCCESS_LOADED;
        loader_log(inst, VULKAN_LOADER_DEBUG_BIT | VULKAN_LOADER_LAYER_BIT, 0, "Loading layer library %s", prop->lib_name);
    }

    return prop->lib_handle;
}

static void loader_close_layer_file(const struct loader_instance *inst, struct loader_layer_properties *prop) {
    if (prop->lib_handle) {
        loader_platform_close_library(prop->lib_handle);
        loader_log(inst, VULKAN_LOADER_DEBUG_BIT | VULKAN_LOADER_LAYER_BIT, 0, "Unloading layer library %s", prop->lib_name);
        prop->lib_handle = NULL;
    }
}

void loader_deactivate_layers(const struct loader_instance *instance, struct loader_device *device,
                              struct loader_layer_list *list) {
    // Delete instance list of enabled layers and close any layer libraries
    for (uint32_t i = 0; i < list->count; i++) {
        struct loader_layer_properties *layer_prop = &list->list[i];

        loader_close_layer_file(instance, layer_prop);
    }
    loader_destroy_layer_list(instance, device, list);
}

// Go through the search_list and find any layers which match type. If layer
// type match is found in then add it to ext_list.
static VkResult loader_add_implicit_layers(const struct loader_instance *inst, const struct loader_envvar_filter *enable_filter,
                                           const struct loader_envvar_disable_layers_filter *disable_filter,
                                           struct loader_layer_list *target_list, struct loader_layer_list *expanded_target_list,
                                           const struct loader_layer_list *source_list) {
    for (uint32_t src_layer = 0; src_layer < source_list->count; src_layer++) {
        const struct loader_layer_properties *prop = &source_list->list[src_layer];
        if (0 == (prop->type_flags & VK_LAYER_TYPE_FLAG_EXPLICIT_LAYER)) {
            VkResult result = loader_add_implicit_layer(inst, prop, enable_filter, disable_filter, target_list,
                                                        expanded_target_list, source_list);
            if (result == VK_ERROR_OUT_OF_HOST_MEMORY) return result;
        }
    }
    return VK_SUCCESS;
}

VkResult loader_enable_instance_layers(struct loader_instance *inst, const VkInstanceCreateInfo *pCreateInfo,
                                       const struct loader_layer_list *instance_layers) {
    VkResult res = VK_SUCCESS;
    struct loader_envvar_filter layers_enable_filter;
    struct loader_envvar_disable_layers_filter layers_disable_filter;

    assert(inst && "Cannot have null instance");

    if (!loader_init_layer_list(inst, &inst->app_activated_layer_list)) {
        loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                   "loader_enable_instance_layers: Failed to initialize application version of the layer list");
        res = VK_ERROR_OUT_OF_HOST_MEMORY;
        goto out;
    }

    if (!loader_init_layer_list(inst, &inst->expanded_activated_layer_list)) {
        loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                   "loader_enable_instance_layers: Failed to initialize expanded version of the layer list");
        res = VK_ERROR_OUT_OF_HOST_MEMORY;
        goto out;
    }

    // Parse the filter environment variables to determine if we have any special behavior
    res = parse_generic_filter_environment_var(inst, VK_LAYERS_ENABLE_ENV_VAR, &layers_enable_filter);
    if (VK_SUCCESS != res) {
        goto out;
    }
    res = parse_layers_disable_filter_environment_var(inst, &layers_disable_filter);
    if (VK_SUCCESS != res) {
        goto out;
    }

    // Add any implicit layers first
    res = loader_add_implicit_layers(inst, &layers_enable_filter, &layers_disable_filter, &inst->app_activated_layer_list,
                                     &inst->expanded_activated_layer_list, instance_layers);
    if (res != VK_SUCCESS) {
        goto out;
    }

    // Add any layers specified via environment variable next
    res = loader_add_environment_layers(inst, VK_LAYER_TYPE_FLAG_EXPLICIT_LAYER, "VK_INSTANCE_LAYERS", &layers_enable_filter,
                                        &layers_disable_filter, &inst->app_activated_layer_list,
                                        &inst->expanded_activated_layer_list, instance_layers);
    if (res != VK_SUCCESS) {
        goto out;
    }

    // Add layers specified by the application
    res = loader_add_layer_names_to_list(inst, &layers_enable_filter, &layers_disable_filter, &inst->app_activated_layer_list,
                                         &inst->expanded_activated_layer_list, pCreateInfo->enabledLayerCount,
                                         pCreateInfo->ppEnabledLayerNames, instance_layers);

    for (uint32_t i = 0; i < inst->expanded_activated_layer_list.count; i++) {
        // Verify that the layer api version is at least that of the application's request, if not, throw a warning since
        // undefined behavior could occur.
        struct loader_layer_properties *prop = inst->expanded_activated_layer_list.list + i;
        loader_api_version prop_spec_version = loader_make_version(prop->info.specVersion);
        if (!loader_check_version_meets_required(inst->app_api_version, prop_spec_version)) {
            loader_log(inst, VULKAN_LOADER_WARN_BIT | VULKAN_LOADER_LAYER_BIT, 0,
                       "Layer %s uses API version %u.%u which is older than the application specified "
                       "API version of %u.%u. May cause issues.",
                       prop->info.layerName, prop_spec_version.major, prop_spec_version.minor, inst->app_api_version.major,
                       inst->app_api_version.minor);
        }
    }
out:
    return res;
}

// Determine the layer interface version to use.
bool loader_get_layer_interface_version(PFN_vkNegotiateLoaderLayerInterfaceVersion fp_negotiate_layer_version,
                                        VkNegotiateLayerInterface *interface_struct) {
    memset(interface_struct, 0, sizeof(VkNegotiateLayerInterface));
    interface_struct->sType = LAYER_NEGOTIATE_INTERFACE_STRUCT;
    interface_struct->loaderLayerInterfaceVersion = 1;
    interface_struct->pNext = NULL;

    if (fp_negotiate_layer_version != NULL) {
        // Layer supports the negotiation API, so call it with the loader's
        // latest version supported
        interface_struct->loaderLayerInterfaceVersion = CURRENT_LOADER_LAYER_INTERFACE_VERSION;
        VkResult result = fp_negotiate_layer_version(interface_struct);

        if (result != VK_SUCCESS) {
            // Layer no longer supports the loader's latest interface version so
            // fail loading the Layer
            return false;
        }
    }

    if (interface_struct->loaderLayerInterfaceVersion < MIN_SUPPORTED_LOADER_LAYER_INTERFACE_VERSION) {
        // Loader no longer supports the layer's latest interface version so
        // fail loading the layer
        return false;
    }

    return true;
}

VKAPI_ATTR VkResult VKAPI_CALL loader_layer_create_device(VkInstance instance, VkPhysicalDevice physicalDevice,
                                                          const VkDeviceCreateInfo *pCreateInfo,
                                                          const VkAllocationCallbacks *pAllocator, VkDevice *pDevice,
                                                          PFN_vkGetInstanceProcAddr layerGIPA, PFN_vkGetDeviceProcAddr *nextGDPA) {
    VkResult res;
    VkPhysicalDevice internal_device = VK_NULL_HANDLE;
    struct loader_device *dev = NULL;
    struct loader_instance *inst = NULL;

    if (instance != VK_NULL_HANDLE) {
        inst = loader_get_instance(instance);
        internal_device = physicalDevice;
    } else {
        struct loader_physical_device_tramp *phys_dev = (struct loader_physical_device_tramp *)physicalDevice;
        internal_device = phys_dev->phys_dev;
        inst = (struct loader_instance *)phys_dev->this_instance;
    }

    // Get the physical device (ICD) extensions
    struct loader_extension_list icd_exts;
    icd_exts.list = NULL;
    res = loader_init_generic_list(inst, (struct loader_generic_list *)&icd_exts, sizeof(VkExtensionProperties));
    if (VK_SUCCESS != res) {
        loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0, "vkCreateDevice: Failed to create ICD extension list");
        goto out;
    }

    PFN_vkEnumerateDeviceExtensionProperties enumDeviceExtensionProperties = NULL;
    if (layerGIPA != NULL) {
        enumDeviceExtensionProperties =
            (PFN_vkEnumerateDeviceExtensionProperties)layerGIPA(instance, "vkEnumerateDeviceExtensionProperties");
    } else {
        enumDeviceExtensionProperties = inst->disp->layer_inst_disp.EnumerateDeviceExtensionProperties;
    }
    res = loader_add_device_extensions(inst, enumDeviceExtensionProperties, internal_device, "Unknown", &icd_exts);
    if (res != VK_SUCCESS) {
        loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0, "vkCreateDevice: Failed to add extensions to list");
        goto out;
    }

    // Make sure requested extensions to be enabled are supported
    res = loader_validate_device_extensions(inst, &inst->expanded_activated_layer_list, &icd_exts, pCreateInfo);
    if (res != VK_SUCCESS) {
        loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0, "vkCreateDevice: Failed to validate extensions in list");
        goto out;
    }

    dev = loader_create_logical_device(inst, pAllocator);
    if (dev == NULL) {
        res = VK_ERROR_OUT_OF_HOST_MEMORY;
        goto out;
    }

    // Copy the application enabled instance layer list into the device
    if (NULL != inst->app_activated_layer_list.list) {
        dev->app_activated_layer_list.capacity = inst->app_activated_layer_list.capacity;
        dev->app_activated_layer_list.count = inst->app_activated_layer_list.count;
        dev->app_activated_layer_list.list =
            loader_device_heap_alloc(dev, inst->app_activated_layer_list.capacity, VK_SYSTEM_ALLOCATION_SCOPE_DEVICE);
        if (dev->app_activated_layer_list.list == NULL) {
            loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                       "vkCreateDevice: Failed to allocate application activated layer list of size %d.",
                       inst->app_activated_layer_list.capacity);
            res = VK_ERROR_OUT_OF_HOST_MEMORY;
            goto out;
        }
        memcpy(dev->app_activated_layer_list.list, inst->app_activated_layer_list.list,
               sizeof(*dev->app_activated_layer_list.list) * dev->app_activated_layer_list.count);
    } else {
        dev->app_activated_layer_list.capacity = 0;
        dev->app_activated_layer_list.count = 0;
        dev->app_activated_layer_list.list = NULL;
    }

    // Copy the expanded enabled instance layer list into the device
    if (NULL != inst->expanded_activated_layer_list.list) {
        dev->expanded_activated_layer_list.capacity = inst->expanded_activated_layer_list.capacity;
        dev->expanded_activated_layer_list.count = inst->expanded_activated_layer_list.count;
        dev->expanded_activated_layer_list.list =
            loader_device_heap_alloc(dev, inst->expanded_activated_layer_list.capacity, VK_SYSTEM_ALLOCATION_SCOPE_DEVICE);
        if (dev->expanded_activated_layer_list.list == NULL) {
            loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                       "vkCreateDevice: Failed to allocate expanded activated layer list of size %d.",
                       inst->expanded_activated_layer_list.capacity);
            res = VK_ERROR_OUT_OF_HOST_MEMORY;
            goto out;
        }
        memcpy(dev->expanded_activated_layer_list.list, inst->expanded_activated_layer_list.list,
               sizeof(*dev->expanded_activated_layer_list.list) * dev->expanded_activated_layer_list.count);
    } else {
        dev->expanded_activated_layer_list.capacity = 0;
        dev->expanded_activated_layer_list.count = 0;
        dev->expanded_activated_layer_list.list = NULL;
    }

    res = loader_create_device_chain(internal_device, pCreateInfo, pAllocator, inst, dev, layerGIPA, nextGDPA);
    if (res != VK_SUCCESS) {
        loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0, "vkCreateDevice:  Failed to create device chain.");
        goto out;
    }

    *pDevice = dev->chain_device;

    // Initialize any device extension dispatch entry's from the instance list
    loader_init_dispatch_dev_ext(inst, dev);

    // Initialize WSI device extensions as part of core dispatch since loader
    // has dedicated trampoline code for these
    loader_init_device_extension_dispatch_table(&dev->loader_dispatch, inst->disp->layer_inst_disp.GetInstanceProcAddr,
                                                dev->loader_dispatch.core_dispatch.GetDeviceProcAddr, inst->instance, *pDevice);

out:

    // Failure cleanup
    if (VK_SUCCESS != res) {
        if (NULL != dev) {
            // Find the icd_term this device belongs to then remove it from that icd_term.
            // Need to iterate the linked lists and remove the device from it. Don't delete
            // the device here since it may not have been added to the icd_term and there
            // are other allocations attached to it.
            struct loader_icd_term *icd_term = inst->icd_terms;
            bool found = false;
            while (!found && NULL != icd_term) {
                struct loader_device *cur_dev = icd_term->logical_device_list;
                struct loader_device *prev_dev = NULL;
                while (NULL != cur_dev) {
                    if (cur_dev == dev) {
                        if (cur_dev == icd_term->logical_device_list) {
                            icd_term->logical_device_list = cur_dev->next;
                        } else if (prev_dev) {
                            prev_dev->next = cur_dev->next;
                        }

                        found = true;
                        break;
                    }
                    prev_dev = cur_dev;
                    cur_dev = cur_dev->next;
                }
                icd_term = icd_term->next;
            }
            // Now destroy the device and the allocations associated with it.
            loader_destroy_logical_device(inst, dev, pAllocator);
        }
    }

    if (NULL != icd_exts.list) {
        loader_destroy_generic_list(inst, (struct loader_generic_list *)&icd_exts);
    }
    return res;
}

VKAPI_ATTR void VKAPI_CALL loader_layer_destroy_device(VkDevice device, const VkAllocationCallbacks *pAllocator,
                                                       PFN_vkDestroyDevice destroyFunction) {
    struct loader_device *dev;

    if (device == VK_NULL_HANDLE) {
        return;
    }

    struct loader_icd_term *icd_term = loader_get_icd_and_device(device, &dev, NULL);
    const struct loader_instance *inst = icd_term->this_instance;

    destroyFunction(device, pAllocator);
    if (NULL != dev) {
        dev->chain_device = NULL;
        dev->icd_device = NULL;
        loader_remove_logical_device(inst, icd_term, dev, pAllocator);
    }
}

// Given the list of layers to activate in the loader_instance
// structure. This function will add a VkLayerInstanceCreateInfo
// structure to the VkInstanceCreateInfo.pNext pointer.
// Each activated layer will have it's own VkLayerInstanceLink
// structure that tells the layer what Get*ProcAddr to call to
// get function pointers to the next layer down.
// Once the chain info has been created this function will
// execute the CreateInstance call chain. Each layer will
// then have an opportunity in it's CreateInstance function
// to setup it's dispatch table when the lower layer returns
// successfully.
// Each layer can wrap or not-wrap the returned VkInstance object
// as it sees fit.
// The instance chain is terminated by a loader function
// that will call CreateInstance on all available ICD's and
// cache those VkInstance objects for future use.
VkResult loader_create_instance_chain(const VkInstanceCreateInfo *pCreateInfo, const VkAllocationCallbacks *pAllocator,
                                      struct loader_instance *inst, VkInstance *created_instance) {
    uint32_t num_activated_layers = 0;
    struct activated_layer_info *activated_layers = NULL;
    VkLayerInstanceCreateInfo chain_info;
    VkLayerInstanceLink *layer_instance_link_info = NULL;
    VkInstanceCreateInfo loader_create_info;
    VkResult res;

    PFN_vkGetInstanceProcAddr next_gipa = loader_gpa_instance_terminator;
    PFN_vkGetInstanceProcAddr cur_gipa = loader_gpa_instance_terminator;
    PFN_vkGetDeviceProcAddr cur_gdpa = loader_gpa_device_terminator;
    PFN_GetPhysicalDeviceProcAddr next_gpdpa = loader_gpdpa_instance_terminator;
    PFN_GetPhysicalDeviceProcAddr cur_gpdpa = loader_gpdpa_instance_terminator;

    memcpy(&loader_create_info, pCreateInfo, sizeof(VkInstanceCreateInfo));

    if (inst->expanded_activated_layer_list.count > 0) {
        chain_info.u.pLayerInfo = NULL;
        chain_info.pNext = pCreateInfo->pNext;
        chain_info.sType = VK_STRUCTURE_TYPE_LOADER_INSTANCE_CREATE_INFO;
        chain_info.function = VK_LAYER_LINK_INFO;
        loader_create_info.pNext = &chain_info;

        layer_instance_link_info = loader_stack_alloc(sizeof(VkLayerInstanceLink) * inst->expanded_activated_layer_list.count);
        if (!layer_instance_link_info) {
            loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                       "loader_create_instance_chain: Failed to alloc Instance objects for layer");
            return VK_ERROR_OUT_OF_HOST_MEMORY;
        }

        activated_layers = loader_stack_alloc(sizeof(struct activated_layer_info) * inst->expanded_activated_layer_list.count);
        if (!activated_layers) {
            loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                       "loader_create_instance_chain: Failed to alloc activated layer storage array");
            return VK_ERROR_OUT_OF_HOST_MEMORY;
        }

        // Create instance chain of enabled layers
        for (int32_t i = inst->expanded_activated_layer_list.count - 1; i >= 0; i--) {
            struct loader_layer_properties *layer_prop = &inst->expanded_activated_layer_list.list[i];
            loader_platform_dl_handle lib_handle;

            // Skip it if a Layer with the same name has been already successfully activated
            if (loader_names_array_has_layer_property(&layer_prop->info, num_activated_layers, activated_layers)) {
                continue;
            }

            lib_handle = loader_open_layer_file(inst, layer_prop);
            if (layer_prop->lib_status == LOADER_LAYER_LIB_ERROR_OUT_OF_MEMORY) {
                return VK_ERROR_OUT_OF_HOST_MEMORY;
            }
            if (!lib_handle) {
                continue;
            }

            if (NULL == layer_prop->functions.negotiate_layer_interface) {
                PFN_vkNegotiateLoaderLayerInterfaceVersion negotiate_interface = NULL;
                bool functions_in_interface = false;
                if (strlen(layer_prop->functions.str_negotiate_interface) == 0) {
                    negotiate_interface = (PFN_vkNegotiateLoaderLayerInterfaceVersion)loader_platform_get_proc_address(
                        lib_handle, "vkNegotiateLoaderLayerInterfaceVersion");
                } else {
                    negotiate_interface = (PFN_vkNegotiateLoaderLayerInterfaceVersion)loader_platform_get_proc_address(
                        lib_handle, layer_prop->functions.str_negotiate_interface);
                }

                // If we can negotiate an interface version, then we can also
                // get everything we need from the one function call, so try
                // that first, and see if we can get all the function pointers
                // necessary from that one call.
                if (NULL != negotiate_interface) {
                    layer_prop->functions.negotiate_layer_interface = negotiate_interface;

                    VkNegotiateLayerInterface interface_struct;

                    if (loader_get_layer_interface_version(negotiate_interface, &interface_struct)) {
                        // Go ahead and set the properties version to the
                        // correct value.
                        layer_prop->interface_version = interface_struct.loaderLayerInterfaceVersion;

                        // If the interface is 2 or newer, we have access to the
                        // new GetPhysicalDeviceProcAddr function, so grab it,
                        // and the other necessary functions, from the
                        // structure.
                        if (interface_struct.loaderLayerInterfaceVersion > 1) {
                            cur_gipa = interface_struct.pfnGetInstanceProcAddr;
                            cur_gdpa = interface_struct.pfnGetDeviceProcAddr;
                            cur_gpdpa = interface_struct.pfnGetPhysicalDeviceProcAddr;
                            if (cur_gipa != NULL) {
                                // We've set the functions, so make sure we
                                // don't do the unnecessary calls later.
                                functions_in_interface = true;
                            }
                        }
                    }
                }

                if (!functions_in_interface) {
                    if ((cur_gipa = layer_prop->functions.get_instance_proc_addr) == NULL) {
                        if (strlen(layer_prop->functions.str_gipa) == 0) {
                            cur_gipa =
                                (PFN_vkGetInstanceProcAddr)loader_platform_get_proc_address(lib_handle, "vkGetInstanceProcAddr");
                            layer_prop->functions.get_instance_proc_addr = cur_gipa;

                            if (NULL == cur_gipa) {
                                loader_log(inst, VULKAN_LOADER_ERROR_BIT | VULKAN_LOADER_LAYER_BIT, 0,
                                           "loader_create_instance_chain: Failed to find \'vkGetInstanceProcAddr\' in layer \"%s\"",
                                           layer_prop->lib_name);
                                continue;
                            }
                        } else {
                            cur_gipa = (PFN_vkGetInstanceProcAddr)loader_platform_get_proc_address(lib_handle,
                                                                                                   layer_prop->functions.str_gipa);

                            if (NULL == cur_gipa) {
                                loader_log(inst, VULKAN_LOADER_ERROR_BIT | VULKAN_LOADER_LAYER_BIT, 0,
                                           "loader_create_instance_chain: Failed to find \'%s\' in layer \"%s\"",
                                           layer_prop->functions.str_gipa, layer_prop->lib_name);
                                continue;
                            }
                        }
                    }
                }
            }

            layer_instance_link_info[num_activated_layers].pNext = chain_info.u.pLayerInfo;
            layer_instance_link_info[num_activated_layers].pfnNextGetInstanceProcAddr = next_gipa;
            layer_instance_link_info[num_activated_layers].pfnNextGetPhysicalDeviceProcAddr = next_gpdpa;
            next_gipa = cur_gipa;
            if (layer_prop->interface_version > 1 && cur_gpdpa != NULL) {
                layer_prop->functions.get_physical_device_proc_addr = cur_gpdpa;
                next_gpdpa = cur_gpdpa;
            }
            if (layer_prop->interface_version > 1 && cur_gipa != NULL) {
                layer_prop->functions.get_instance_proc_addr = cur_gipa;
            }
            if (layer_prop->interface_version > 1 && cur_gdpa != NULL) {
                layer_prop->functions.get_device_proc_addr = cur_gdpa;
            }

            chain_info.u.pLayerInfo = &layer_instance_link_info[num_activated_layers];

            activated_layers[num_activated_layers].name = layer_prop->info.layerName;
            activated_layers[num_activated_layers].manifest = layer_prop->manifest_file_name;
            activated_layers[num_activated_layers].library = layer_prop->lib_name;
            activated_layers[num_activated_layers].is_implicit = !(layer_prop->type_flags & VK_LAYER_TYPE_FLAG_EXPLICIT_LAYER);
            if (activated_layers[num_activated_layers].is_implicit) {
                activated_layers[num_activated_layers].disable_env = layer_prop->disable_env_var.name;
            }

            loader_log(inst, VULKAN_LOADER_INFO_BIT | VULKAN_LOADER_LAYER_BIT, 0, "Insert instance layer \"%s\" (%s)",
                       layer_prop->info.layerName, layer_prop->lib_name);

            num_activated_layers++;
        }
    }

    // Make sure each layer requested by the application was actually loaded
    for (uint32_t exp = 0; exp < inst->expanded_activated_layer_list.count; ++exp) {
        struct loader_layer_properties *exp_layer_prop = &inst->expanded_activated_layer_list.list[exp];
        bool found = false;
        for (uint32_t act = 0; act < num_activated_layers; ++act) {
            if (!strcmp(activated_layers[act].name, exp_layer_prop->info.layerName)) {
                found = true;
                break;
            }
        }
        // If it wasn't found, we want to at least log an error.  However, if it was enabled by the application directly,
        // we want to return a bad layer error.
        if (!found) {
            bool app_requested = false;
            for (uint32_t act = 0; act < pCreateInfo->enabledLayerCount; ++act) {
                if (!strcmp(pCreateInfo->ppEnabledLayerNames[act], exp_layer_prop->info.layerName)) {
                    app_requested = true;
                    break;
                }
            }
            VkFlags log_flag = VULKAN_LOADER_LAYER_BIT;
            char ending = '.';
            if (app_requested) {
                log_flag |= VULKAN_LOADER_ERROR_BIT;
                ending = '!';
            } else {
                log_flag |= VULKAN_LOADER_INFO_BIT;
            }
            switch (exp_layer_prop->lib_status) {
                case LOADER_LAYER_LIB_NOT_LOADED:
                    loader_log(inst, log_flag, 0, "Requested layer \"%s\" was not loaded%c", exp_layer_prop->info.layerName,
                               ending);
                    break;
                case LOADER_LAYER_LIB_ERROR_WRONG_BIT_TYPE: {
                    loader_log(inst, log_flag, 0, "Requested layer \"%s\" was wrong bit-type%c", exp_layer_prop->info.layerName,
                               ending);
                    break;
                }
                case LOADER_LAYER_LIB_ERROR_FAILED_TO_LOAD:
                    loader_log(inst, log_flag, 0, "Requested layer \"%s\" failed to load%c", exp_layer_prop->info.layerName,
                               ending);
                    break;
                case LOADER_LAYER_LIB_SUCCESS_LOADED:
                case LOADER_LAYER_LIB_ERROR_OUT_OF_MEMORY:
                    // Shouldn't be able to reach this but if it is, best to report a debug
                    loader_log(inst, log_flag, 0,
                               "Shouldn't reach this. A valid version of requested layer %s was loaded but was not found in the "
                               "list of activated layers%c",
                               exp_layer_prop->info.layerName, ending);
                    break;
            }
            if (app_requested) {
                return VK_ERROR_LAYER_NOT_PRESENT;
            }
        }
    }

    VkLoaderFeatureFlags feature_flags = 0;
#if defined(_WIN32)
    feature_flags = windows_initialize_dxgi();
#endif

    PFN_vkCreateInstance fpCreateInstance = (PFN_vkCreateInstance)next_gipa(*created_instance, "vkCreateInstance");
    if (fpCreateInstance) {
        VkLayerInstanceCreateInfo instance_dispatch;
        instance_dispatch.sType = VK_STRUCTURE_TYPE_LOADER_INSTANCE_CREATE_INFO;
        instance_dispatch.pNext = loader_create_info.pNext;
        instance_dispatch.function = VK_LOADER_DATA_CALLBACK;
        instance_dispatch.u.pfnSetInstanceLoaderData = vkSetInstanceDispatch;

        VkLayerInstanceCreateInfo device_callback;
        device_callback.sType = VK_STRUCTURE_TYPE_LOADER_INSTANCE_CREATE_INFO;
        device_callback.pNext = &instance_dispatch;
        device_callback.function = VK_LOADER_LAYER_CREATE_DEVICE_CALLBACK;
        device_callback.u.layerDevice.pfnLayerCreateDevice = loader_layer_create_device;
        device_callback.u.layerDevice.pfnLayerDestroyDevice = loader_layer_destroy_device;

        VkLayerInstanceCreateInfo loader_features;
        loader_features.sType = VK_STRUCTURE_TYPE_LOADER_INSTANCE_CREATE_INFO;
        loader_features.pNext = &device_callback;
        loader_features.function = VK_LOADER_FEATURES;
        loader_features.u.loaderFeatures = feature_flags;

        loader_create_info.pNext = &loader_features;

        // If layer debugging is enabled, let's print out the full callstack with layers in their
        // defined order.
        if ((loader_get_debug_level() & VULKAN_LOADER_LAYER_BIT) != 0) {
            loader_log(inst, VULKAN_LOADER_LAYER_BIT, 0, "vkCreateInstance layer callstack setup to:");
            loader_log(inst, VULKAN_LOADER_LAYER_BIT, 0, "   <Application>");
            loader_log(inst, VULKAN_LOADER_LAYER_BIT, 0, "     ||");
            loader_log(inst, VULKAN_LOADER_LAYER_BIT, 0, "   <Loader>");
            loader_log(inst, VULKAN_LOADER_LAYER_BIT, 0, "     ||");
            for (uint32_t cur_layer = 0; cur_layer < num_activated_layers; ++cur_layer) {
                uint32_t index = num_activated_layers - cur_layer - 1;
                loader_log(inst, VULKAN_LOADER_LAYER_BIT, 0, "   %s", activated_layers[index].name);
                loader_log(inst, VULKAN_LOADER_LAYER_BIT, 0, "           Type: %s",
                           activated_layers[index].is_implicit ? "Implicit" : "Explicit");
                if (activated_layers[index].is_implicit) {
                    loader_log(inst, VULKAN_LOADER_LAYER_BIT, 0, "               Disable Env Var:  %s",
                               activated_layers[index].disable_env);
                }
                loader_log(inst, VULKAN_LOADER_LAYER_BIT, 0, "           Manifest: %s", activated_layers[index].manifest);
                loader_log(inst, VULKAN_LOADER_LAYER_BIT, 0, "           Library:  %s", activated_layers[index].library);
                loader_log(inst, VULKAN_LOADER_LAYER_BIT, 0, "     ||");
            }
            loader_log(inst, VULKAN_LOADER_LAYER_BIT, 0, "   <Drivers>");
        }

        res = fpCreateInstance(&loader_create_info, pAllocator, created_instance);
    } else {
        loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0, "loader_create_instance_chain: Failed to find \'vkCreateInstance\'");
        // Couldn't find CreateInstance function!
        res = VK_ERROR_INITIALIZATION_FAILED;
    }

    if (res == VK_SUCCESS) {
        loader_init_instance_core_dispatch_table(&inst->disp->layer_inst_disp, next_gipa, *created_instance);
        inst->instance = *created_instance;
    }

    if (pCreateInfo->enabledLayerCount > 0 && pCreateInfo->ppEnabledLayerNames != NULL) {
        inst->enabled_layer_count = pCreateInfo->enabledLayerCount;

        inst->enabled_layer_names = (char **)loader_instance_heap_calloc(inst, sizeof(char *) * pCreateInfo->enabledLayerCount,
                                                                         VK_SYSTEM_ALLOCATION_SCOPE_INSTANCE);

        for (uint32_t i = 0, n = inst->enabled_layer_count; i < n; ++i) {
            size_t size = strlen(pCreateInfo->ppEnabledLayerNames[i]) + 1;
            inst->enabled_layer_names[i] =
                (char *)loader_instance_heap_calloc(inst, sizeof(char) * size, VK_SYSTEM_ALLOCATION_SCOPE_INSTANCE);
            strncpy(inst->enabled_layer_names[i], pCreateInfo->ppEnabledLayerNames[i], strlen(pCreateInfo->ppEnabledLayerNames[i]));
        }
    }

    return res;
}

void loader_activate_instance_layer_extensions(struct loader_instance *inst, VkInstance created_inst) {
    loader_init_instance_extension_dispatch_table(&inst->disp->layer_inst_disp, inst->disp->layer_inst_disp.GetInstanceProcAddr,
                                                  created_inst);
}

#ifdef __APPLE__
VkResult loader_create_device_chain(const VkPhysicalDevice pd, const VkDeviceCreateInfo *pCreateInfo,
                                    const VkAllocationCallbacks *pAllocator, const struct loader_instance *inst,
                                    struct loader_device *dev, PFN_vkGetInstanceProcAddr callingLayer,
                                    PFN_vkGetDeviceProcAddr *layerNextGDPA) __attribute__((optnone)) {
#else
VkResult loader_create_device_chain(const VkPhysicalDevice pd, const VkDeviceCreateInfo *pCreateInfo,
                                    const VkAllocationCallbacks *pAllocator, const struct loader_instance *inst,
                                    struct loader_device *dev, PFN_vkGetInstanceProcAddr callingLayer,
                                    PFN_vkGetDeviceProcAddr *layerNextGDPA) {
#endif
    uint32_t num_activated_layers = 0;
    struct activated_layer_info *activated_layers = NULL;
    VkLayerDeviceLink *layer_device_link_info;
    VkLayerDeviceCreateInfo chain_info;
    VkDeviceCreateInfo loader_create_info;
    VkDeviceGroupDeviceCreateInfoKHR *original_device_group_create_info_struct = NULL;
    VkResult res;

    PFN_vkGetDeviceProcAddr fpGDPA = NULL, nextGDPA = loader_gpa_device_terminator;
    PFN_vkGetInstanceProcAddr fpGIPA = NULL, nextGIPA = loader_gpa_instance_terminator;

    memcpy(&loader_create_info, pCreateInfo, sizeof(VkDeviceCreateInfo));

    if (loader_create_info.enabledLayerCount > 0 && loader_create_info.ppEnabledLayerNames != NULL) {
        bool invalid_device_layer_usage = false;

        if (loader_create_info.enabledLayerCount != inst->enabled_layer_count && loader_create_info.enabledLayerCount > 0) {
            invalid_device_layer_usage = true;
        } else if (loader_create_info.enabledLayerCount > 0 && loader_create_info.ppEnabledLayerNames == NULL) {
            invalid_device_layer_usage = true;
        } else if (loader_create_info.enabledLayerCount == 0 && loader_create_info.ppEnabledLayerNames != NULL) {
            invalid_device_layer_usage = true;
        } else if (inst->enabled_layer_names != NULL) {
            for (uint32_t i = 0; i < loader_create_info.enabledLayerCount; i++) {
                const char *device_layer_names = loader_create_info.ppEnabledLayerNames[i];

                if (strcmp(device_layer_names, inst->enabled_layer_names[i]) != 0) {
                    invalid_device_layer_usage = true;
                    break;
                }
            }
        }

        if (invalid_device_layer_usage) {
            loader_log(
                inst, VULKAN_LOADER_WARN_BIT, 0,
                "loader_create_device_chain: Using deprecated and ignored 'ppEnabledLayerNames' member of 'VkDeviceCreateInfo' "
                "when creating a Vulkan device.");
        }
    }

    // Before we continue, we need to find out if the KHR_device_group extension is in the enabled list.  If it is, we then
    // need to look for the corresponding VkDeviceGroupDeviceCreateInfoKHR struct in the device list.  This is because we
    // need to replace all the incoming physical device values (which are really loader trampoline physical device values)
    // with the layer/ICD version.
    {
        VkBaseOutStructure *pNext = (VkBaseOutStructure *)loader_create_info.pNext;
        VkBaseOutStructure *pPrev = (VkBaseOutStructure *)&loader_create_info;
        while (NULL != pNext) {
            if (VK_STRUCTURE_TYPE_DEVICE_GROUP_DEVICE_CREATE_INFO == pNext->sType) {
                VkDeviceGroupDeviceCreateInfoKHR *cur_struct = (VkDeviceGroupDeviceCreateInfoKHR *)pNext;
                if (0 < cur_struct->physicalDeviceCount && NULL != cur_struct->pPhysicalDevices) {
                    VkDeviceGroupDeviceCreateInfoKHR *temp_struct = loader_stack_alloc(sizeof(VkDeviceGroupDeviceCreateInfoKHR));
                    VkPhysicalDevice *phys_dev_array = NULL;
                    if (NULL == temp_struct) {
                        return VK_ERROR_OUT_OF_HOST_MEMORY;
                    }
                    memcpy(temp_struct, cur_struct, sizeof(VkDeviceGroupDeviceCreateInfoKHR));
                    phys_dev_array = loader_stack_alloc(sizeof(VkPhysicalDevice) * cur_struct->physicalDeviceCount);
                    if (NULL == phys_dev_array) {
                        return VK_ERROR_OUT_OF_HOST_MEMORY;
                    }

                    // Before calling down, replace the incoming physical device values (which are really loader trampoline
                    // physical devices) with the next layer (or possibly even the terminator) physical device values.
                    struct loader_physical_device_tramp *cur_tramp;
                    for (uint32_t phys_dev = 0; phys_dev < cur_struct->physicalDeviceCount; phys_dev++) {
                        cur_tramp = (struct loader_physical_device_tramp *)cur_struct->pPhysicalDevices[phys_dev];
                        phys_dev_array[phys_dev] = cur_tramp->phys_dev;
                    }
                    temp_struct->pPhysicalDevices = phys_dev_array;

                    original_device_group_create_info_struct = (VkDeviceGroupDeviceCreateInfoKHR *)pPrev->pNext;

                    // Replace the old struct in the pNext chain with this one.
                    pPrev->pNext = (VkBaseOutStructure *)temp_struct;
                }
                break;
            }

            pPrev = pNext;
            pNext = pNext->pNext;
        }
    }
    if (dev->expanded_activated_layer_list.count > 0) {
        layer_device_link_info = loader_stack_alloc(sizeof(VkLayerDeviceLink) * dev->expanded_activated_layer_list.count);
        if (!layer_device_link_info) {
            loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                       "loader_create_device_chain: Failed to alloc Device objects for layer. Skipping Layer.");
            return VK_ERROR_OUT_OF_HOST_MEMORY;
        }

        activated_layers = loader_stack_alloc(sizeof(struct activated_layer_info) * inst->expanded_activated_layer_list.count);
        if (!activated_layers) {
            loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                       "loader_create_device_chain: Failed to alloc activated layer storage array");
            return VK_ERROR_OUT_OF_HOST_MEMORY;
        }

        chain_info.sType = VK_STRUCTURE_TYPE_LOADER_DEVICE_CREATE_INFO;
        chain_info.function = VK_LAYER_LINK_INFO;
        chain_info.u.pLayerInfo = NULL;
        chain_info.pNext = loader_create_info.pNext;
        loader_create_info.pNext = &chain_info;

        // Create instance chain of enabled layers
        for (int32_t i = dev->expanded_activated_layer_list.count - 1; i >= 0; i--) {
            struct loader_layer_properties *layer_prop = &dev->expanded_activated_layer_list.list[i];
            loader_platform_dl_handle lib_handle = layer_prop->lib_handle;

            // Skip it if a Layer with the same name has been already successfully activated
            if (loader_names_array_has_layer_property(&layer_prop->info, num_activated_layers, activated_layers)) {
                continue;
            }

            // Skip the layer if the handle is NULL - this is likely because the library failed to load but wasn't removed from
            // the list.
            if (!lib_handle) {
                continue;
            }

            // The Get*ProcAddr pointers will already be filled in if they were received from either the json file or the
            // version negotiation
            if ((fpGIPA = layer_prop->functions.get_instance_proc_addr) == NULL) {
                if (strlen(layer_prop->functions.str_gipa) == 0) {
                    fpGIPA = (PFN_vkGetInstanceProcAddr)loader_platform_get_proc_address(lib_handle, "vkGetInstanceProcAddr");
                    layer_prop->functions.get_instance_proc_addr = fpGIPA;
                } else
                    fpGIPA =
                        (PFN_vkGetInstanceProcAddr)loader_platform_get_proc_address(lib_handle, layer_prop->functions.str_gipa);
                if (!fpGIPA) {
                    loader_log(inst, VULKAN_LOADER_ERROR_BIT | VULKAN_LOADER_LAYER_BIT, 0,
                               "loader_create_device_chain: Failed to find \'vkGetInstanceProcAddr\' in layer \"%s\".  "
                               "Skipping layer.",
                               layer_prop->lib_name);
                    continue;
                }
            }

            if (fpGIPA == callingLayer) {
                if (layerNextGDPA != NULL) {
                    *layerNextGDPA = nextGDPA;
                }
                // Break here because if fpGIPA is the same as callingLayer, that means a layer is trying to create a device,
                // and once we don't want to continue any further as the next layer will be the calling layer
                break;
            }

            if ((fpGDPA = layer_prop->functions.get_device_proc_addr) == NULL) {
                if (strlen(layer_prop->functions.str_gdpa) == 0) {
                    fpGDPA = (PFN_vkGetDeviceProcAddr)loader_platform_get_proc_address(lib_handle, "vkGetDeviceProcAddr");
                    layer_prop->functions.get_device_proc_addr = fpGDPA;
                } else
                    fpGDPA = (PFN_vkGetDeviceProcAddr)loader_platform_get_proc_address(lib_handle, layer_prop->functions.str_gdpa);
                if (!fpGDPA) {
                    loader_log(inst, VULKAN_LOADER_INFO_BIT | VULKAN_LOADER_LAYER_BIT, 0,
                               "Failed to find vkGetDeviceProcAddr in layer \"%s\"", layer_prop->lib_name);
                    continue;
                }
            }

            layer_device_link_info[num_activated_layers].pNext = chain_info.u.pLayerInfo;
            layer_device_link_info[num_activated_layers].pfnNextGetInstanceProcAddr = nextGIPA;
            layer_device_link_info[num_activated_layers].pfnNextGetDeviceProcAddr = nextGDPA;
            chain_info.u.pLayerInfo = &layer_device_link_info[num_activated_layers];
            nextGIPA = fpGIPA;
            nextGDPA = fpGDPA;

            activated_layers[num_activated_layers].name = layer_prop->info.layerName;
            activated_layers[num_activated_layers].manifest = layer_prop->manifest_file_name;
            activated_layers[num_activated_layers].library = layer_prop->lib_name;
            activated_layers[num_activated_layers].is_implicit = !(layer_prop->type_flags & VK_LAYER_TYPE_FLAG_EXPLICIT_LAYER);
            if (activated_layers[num_activated_layers].is_implicit) {
                activated_layers[num_activated_layers].disable_env = layer_prop->disable_env_var.name;
            }

            loader_log(inst, VULKAN_LOADER_INFO_BIT | VULKAN_LOADER_LAYER_BIT, 0, "Inserted device layer \"%s\" (%s)",
                       layer_prop->info.layerName, layer_prop->lib_name);

            num_activated_layers++;
        }
    }

    VkDevice created_device = (VkDevice)dev;
    PFN_vkCreateDevice fpCreateDevice = (PFN_vkCreateDevice)nextGIPA(inst->instance, "vkCreateDevice");
    if (fpCreateDevice) {
        VkLayerDeviceCreateInfo create_info_disp;

        create_info_disp.sType = VK_STRUCTURE_TYPE_LOADER_DEVICE_CREATE_INFO;
        create_info_disp.function = VK_LOADER_DATA_CALLBACK;

        create_info_disp.u.pfnSetDeviceLoaderData = vkSetDeviceDispatch;

        // If layer debugging is enabled, let's print out the full callstack with layers in their
        // defined order.
        uint32_t layer_driver_bits = VULKAN_LOADER_LAYER_BIT | VULKAN_LOADER_DRIVER_BIT;
        if ((loader_get_debug_level() & layer_driver_bits) != 0) {
            loader_log(inst, layer_driver_bits, 0, "vkCreateDevice layer callstack setup to:");
            loader_log(inst, layer_driver_bits, 0, "   <Application>");
            loader_log(inst, layer_driver_bits, 0, "     ||");
            loader_log(inst, layer_driver_bits, 0, "   <Loader>");
            loader_log(inst, layer_driver_bits, 0, "     ||");
            if ((loader_get_debug_level() & VULKAN_LOADER_LAYER_BIT) != 0) {
                for (uint32_t cur_layer = 0; cur_layer < num_activated_layers; ++cur_layer) {
                    uint32_t index = num_activated_layers - cur_layer - 1;
                    loader_log(inst, VULKAN_LOADER_LAYER_BIT, 0, "   %s", activated_layers[index].name);
                    loader_log(inst, VULKAN_LOADER_LAYER_BIT, 0, "           Type: %s",
                               activated_layers[index].is_implicit ? "Implicit" : "Explicit");
                    if (activated_layers[index].is_implicit) {
                        loader_log(inst, VULKAN_LOADER_LAYER_BIT, 0, "               Disable Env Var:  %s",
                                   activated_layers[index].disable_env);
                    }
                    loader_log(inst, VULKAN_LOADER_LAYER_BIT, 0, "           Manifest: %s", activated_layers[index].manifest);
                    loader_log(inst, VULKAN_LOADER_LAYER_BIT, 0, "           Library:  %s", activated_layers[index].library);
                    loader_log(inst, VULKAN_LOADER_LAYER_BIT, 0, "     ||");
                }
            }
            loader_log(inst, layer_driver_bits, 0, "   <Device>");
        }
        create_info_disp.pNext = loader_create_info.pNext;
        loader_create_info.pNext = &create_info_disp;
        res = fpCreateDevice(pd, &loader_create_info, pAllocator, &created_device);
        if (res != VK_SUCCESS) {
            return res;
        }
        dev->chain_device = created_device;

        // Because we changed the pNext chain to use our own VkDeviceGroupDeviceCreateInfoKHR, we need to fixup the chain to
        // point back at the original VkDeviceGroupDeviceCreateInfoKHR.
        VkBaseOutStructure *pNext = (VkBaseOutStructure *)loader_create_info.pNext;
        VkBaseOutStructure *pPrev = (VkBaseOutStructure *)&loader_create_info;
        while (NULL != pNext) {
            if (VK_STRUCTURE_TYPE_DEVICE_GROUP_DEVICE_CREATE_INFO == pNext->sType) {
                VkDeviceGroupDeviceCreateInfoKHR *cur_struct = (VkDeviceGroupDeviceCreateInfoKHR *)pNext;
                if (0 < cur_struct->physicalDeviceCount && NULL != cur_struct->pPhysicalDevices) {
                    pPrev->pNext = (VkBaseOutStructure *)original_device_group_create_info_struct;
                }
                break;
            }

            pPrev = pNext;
            pNext = pNext->pNext;
        }

    } else {
        loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                   "loader_create_device_chain: Failed to find \'vkCreateDevice\' in layers or ICD");
        // Couldn't find CreateDevice function!
        return VK_ERROR_INITIALIZATION_FAILED;
    }

    // Initialize device dispatch table
    loader_init_device_dispatch_table(&dev->loader_dispatch, nextGDPA, dev->chain_device);
    // Initialize the dispatch table to functions which need terminators
    // These functions point directly to the driver, not the terminator functions
    init_extension_device_proc_terminator_dispatch(dev);

    return res;
}

VkResult loader_validate_layers(const struct loader_instance *inst, const uint32_t layer_count,
                                const char *const *ppEnabledLayerNames, const struct loader_layer_list *list) {
    struct loader_layer_properties *prop;

    if (layer_count > 0 && ppEnabledLayerNames == NULL) {
        loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                   "loader_validate_instance_layers: ppEnabledLayerNames is NULL but enabledLayerCount is greater than zero");
        return VK_ERROR_LAYER_NOT_PRESENT;
    }

    for (uint32_t i = 0; i < layer_count; i++) {
        VkStringErrorFlags result = vk_string_validate(MaxLoaderStringLength, ppEnabledLayerNames[i]);
        if (result != VK_STRING_ERROR_NONE) {
            loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                       "loader_validate_layers: ppEnabledLayerNames contains string that is too long or is badly formed");
            return VK_ERROR_LAYER_NOT_PRESENT;
        }

        prop = loader_find_layer_property(ppEnabledLayerNames[i], list);
        if (NULL == prop) {
            loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                       "loader_validate_layers: Layer %d does not exist in the list of available layers", i);
            return VK_ERROR_LAYER_NOT_PRESENT;
        }
    }
    return VK_SUCCESS;
}

VkResult loader_validate_instance_extensions(struct loader_instance *inst, const struct loader_extension_list *icd_exts,
                                             const struct loader_layer_list *instance_layers,
                                             const VkInstanceCreateInfo *pCreateInfo) {
    VkExtensionProperties *extension_prop;
    char *env_value;
    bool check_if_known = true;
    VkResult res = VK_SUCCESS;
    struct loader_envvar_filter layers_enable_filter;
    struct loader_envvar_disable_layers_filter layers_disable_filter;

    struct loader_layer_list active_layers;
    struct loader_layer_list expanded_layers;
    memset(&active_layers, 0, sizeof(active_layers));
    memset(&expanded_layers, 0, sizeof(expanded_layers));

    if (pCreateInfo->enabledExtensionCount > 0 && pCreateInfo->ppEnabledExtensionNames == NULL) {
        loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                   "loader_validate_instance_extensions: Instance ppEnabledExtensionNames is NULL but enabledExtensionCount is "
                   "greater than zero");
        return VK_ERROR_EXTENSION_NOT_PRESENT;
    }
    if (!loader_init_layer_list(inst, &active_layers)) {
        res = VK_ERROR_OUT_OF_HOST_MEMORY;
        goto out;
    }
    if (!loader_init_layer_list(inst, &expanded_layers)) {
        res = VK_ERROR_OUT_OF_HOST_MEMORY;
        goto out;
    }

    // Parse the filter environment variables to determine if we have any special behavior
    res = parse_generic_filter_environment_var(inst, VK_LAYERS_ENABLE_ENV_VAR, &layers_enable_filter);
    if (VK_SUCCESS != res) {
        goto out;
    }
    res = parse_layers_disable_filter_environment_var(inst, &layers_disable_filter);
    if (VK_SUCCESS != res) {
        goto out;
    }

    // Build the lists of active layers (including metalayers) and expanded layers (with metalayers resolved to their
    // components)
    res = loader_add_implicit_layers(inst, &layers_enable_filter, &layers_disable_filter, &active_layers, &expanded_layers,
                                     instance_layers);
    if (res != VK_SUCCESS) {
        goto out;
    }
    res = loader_add_environment_layers(inst, VK_LAYER_TYPE_FLAG_EXPLICIT_LAYER, ENABLED_LAYERS_ENV, &layers_enable_filter,
                                        &layers_disable_filter, &active_layers, &expanded_layers, instance_layers);
    if (res != VK_SUCCESS) {
        goto out;
    }
    res = loader_add_layer_names_to_list(inst, &layers_enable_filter, &layers_disable_filter, &active_layers, &expanded_layers,
                                         pCreateInfo->enabledLayerCount, pCreateInfo->ppEnabledLayerNames, instance_layers);
    if (VK_SUCCESS != res) {
        goto out;
    }

    for (uint32_t i = 0; i < pCreateInfo->enabledExtensionCount; i++) {
        VkStringErrorFlags result = vk_string_validate(MaxLoaderStringLength, pCreateInfo->ppEnabledExtensionNames[i]);
        if (result != VK_STRING_ERROR_NONE) {
            loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                       "loader_validate_instance_extensions: Instance ppEnabledExtensionNames contains "
                       "string that is too long or is badly formed");
            res = VK_ERROR_EXTENSION_NOT_PRESENT;
            goto out;
        }

        // Check if a user wants to disable the instance extension filtering behavior
        env_value = loader_getenv("VK_LOADER_DISABLE_INST_EXT_FILTER", inst);
        if (NULL != env_value && atoi(env_value) != 0) {
            check_if_known = false;
        }
        loader_free_getenv(env_value, inst);

        if (check_if_known) {
            // See if the extension is in the list of supported extensions
            bool found = false;
            for (uint32_t j = 0; LOADER_INSTANCE_EXTENSIONS[j] != NULL; j++) {
                if (strcmp(pCreateInfo->ppEnabledExtensionNames[i], LOADER_INSTANCE_EXTENSIONS[j]) == 0) {
                    found = true;
                    break;
                }
            }

            // If it isn't in the list, return an error
            if (!found) {
                loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                           "loader_validate_instance_extensions: Extension %s not found in list of known instance extensions.",
                           pCreateInfo->ppEnabledExtensionNames[i]);
                res = VK_ERROR_EXTENSION_NOT_PRESENT;
                goto out;
            }
        }

        extension_prop = get_extension_property(pCreateInfo->ppEnabledExtensionNames[i], icd_exts);

        if (extension_prop) {
            continue;
        }

        extension_prop = NULL;

        // Not in global list, search layer extension lists
        struct loader_layer_properties *layer_prop = NULL;
        for (uint32_t j = 0; NULL == extension_prop && j < expanded_layers.count; ++j) {
            extension_prop =
                get_extension_property(pCreateInfo->ppEnabledExtensionNames[i], &expanded_layers.list[j].instance_extension_list);
            if (extension_prop) {
                // Found the extension in one of the layers enabled by the app.
                break;
            }

            layer_prop = loader_find_layer_property(expanded_layers.list[j].info.layerName, instance_layers);
            if (NULL == layer_prop) {
                // Should NOT get here, loader_validate_layers should have already filtered this case out.
                continue;
            }
        }

        if (!extension_prop) {
            // Didn't find extension name in any of the global layers, error out
            loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                       "loader_validate_instance_extensions: Instance extension %s not supported by available ICDs or enabled "
                       "layers.",
                       pCreateInfo->ppEnabledExtensionNames[i]);
            res = VK_ERROR_EXTENSION_NOT_PRESENT;
            goto out;
        }
    }

out:
    loader_destroy_layer_list(inst, NULL, &active_layers);
    loader_destroy_layer_list(inst, NULL, &expanded_layers);
    return res;
}

VkResult loader_validate_device_extensions(struct loader_instance *this_instance,
                                           const struct loader_layer_list *activated_device_layers,
                                           const struct loader_extension_list *icd_exts, const VkDeviceCreateInfo *pCreateInfo) {
    VkExtensionProperties *extension_prop;
    struct loader_layer_properties *layer_prop;

    for (uint32_t i = 0; i < pCreateInfo->enabledExtensionCount; i++) {
        VkStringErrorFlags result = vk_string_validate(MaxLoaderStringLength, pCreateInfo->ppEnabledExtensionNames[i]);
        if (result != VK_STRING_ERROR_NONE) {
            loader_log(this_instance, VULKAN_LOADER_ERROR_BIT, 0,
                       "loader_validate_device_extensions: Device ppEnabledExtensionNames contains "
                       "string that is too long or is badly formed");
            return VK_ERROR_EXTENSION_NOT_PRESENT;
        }

        const char *extension_name = pCreateInfo->ppEnabledExtensionNames[i];
        extension_prop = get_extension_property(extension_name, icd_exts);

        if (extension_prop) {
            continue;
        }

        // Not in global list, search activated layer extension lists
        for (uint32_t j = 0; j < activated_device_layers->count; j++) {
            layer_prop = &activated_device_layers->list[j];

            extension_prop = get_dev_extension_property(extension_name, &layer_prop->device_extension_list);
            if (extension_prop) {
                // Found the extension in one of the layers enabled by the app.
                break;
            }
        }

        if (!extension_prop) {
            // Didn't find extension name in any of the device layers, error out
            loader_log(this_instance, VULKAN_LOADER_ERROR_BIT, 0,
                       "loader_validate_device_extensions: Device extension %s not supported by selected physical device "
                       "or enabled layers.",
                       pCreateInfo->ppEnabledExtensionNames[i]);
            return VK_ERROR_EXTENSION_NOT_PRESENT;
        }
    }
    return VK_SUCCESS;
}

// Terminator functions for the Instance chain
// All named terminator_<Vulkan API name>
VKAPI_ATTR VkResult VKAPI_CALL terminator_CreateInstance(const VkInstanceCreateInfo *pCreateInfo,
                                                         const VkAllocationCallbacks *pAllocator, VkInstance *pInstance) {
    struct loader_icd_term *icd_term;
    VkExtensionProperties *prop;
    char **filtered_extension_names = NULL;
    VkInstanceCreateInfo icd_create_info;
    VkResult res = VK_SUCCESS;
    bool one_icd_successful = false;

    struct loader_instance *ptr_instance = (struct loader_instance *)*pInstance;
    if (NULL == ptr_instance) {
        loader_log(ptr_instance, VULKAN_LOADER_WARN_BIT, 0,
                   "terminator_CreateInstance: Loader instance pointer null encountered.  Possibly set by active layer. (Policy "
                   "#LLP_LAYER_21)");
    } else if (LOADER_MAGIC_NUMBER != ptr_instance->magic) {
        loader_log(ptr_instance, VULKAN_LOADER_WARN_BIT, 0,
                   "terminator_CreateInstance: Instance pointer (%p) has invalid MAGIC value 0x%08x. Instance value possibly "
                   "corrupted by active layer (Policy #LLP_LAYER_21).  ",
                   ptr_instance->magic);
    }

    // Save the application version if it has been modified - layers sometimes needs features in newer API versions than
    // what the application requested, and thus will increase the instance version to a level that suites their needs.
    if (pCreateInfo->pApplicationInfo && pCreateInfo->pApplicationInfo->apiVersion) {
        loader_api_version altered_version = loader_make_version(pCreateInfo->pApplicationInfo->apiVersion);
        if (altered_version.major != ptr_instance->app_api_version.major ||
            altered_version.minor != ptr_instance->app_api_version.minor) {
            ptr_instance->app_api_version = altered_version;
        }
    }

    memcpy(&icd_create_info, pCreateInfo, sizeof(icd_create_info));

    icd_create_info.enabledLayerCount = 0;
    icd_create_info.ppEnabledLayerNames = NULL;

    // NOTE: Need to filter the extensions to only those supported by the ICD.
    //       No ICD will advertise support for layers. An ICD library could
    //       support a layer, but it would be independent of the actual ICD,
    //       just in the same library.
    uint32_t extension_count = pCreateInfo->enabledExtensionCount;
#ifdef LOADER_ENABLE_LINUX_SORT
    extension_count += 1;
#endif  // LOADER_ENABLE_LINUX_SORT
    filtered_extension_names = loader_stack_alloc(extension_count * sizeof(char *));
    if (!filtered_extension_names) {
        loader_log(ptr_instance, VULKAN_LOADER_ERROR_BIT, 0,
                   "terminator_CreateInstance: Failed create extension name array for %d extensions", extension_count);
        res = VK_ERROR_OUT_OF_HOST_MEMORY;
        goto out;
    }
    icd_create_info.ppEnabledExtensionNames = (const char *const *)filtered_extension_names;

    // Determine if Get Physical Device Properties 2 is available to this Instance
    if (pCreateInfo->pApplicationInfo && pCreateInfo->pApplicationInfo->apiVersion >= VK_API_VERSION_1_1) {
        ptr_instance->supports_get_dev_prop_2 = true;
    } else {
        for (uint32_t j = 0; j < pCreateInfo->enabledExtensionCount; j++) {
            if (!strcmp(pCreateInfo->ppEnabledExtensionNames[j], VK_KHR_GET_PHYSICAL_DEVICE_PROPERTIES_2_EXTENSION_NAME)) {
                ptr_instance->supports_get_dev_prop_2 = true;
                break;
            }
        }
    }

    for (uint32_t i = 0; i < ptr_instance->icd_tramp_list.count; i++) {
        icd_term = loader_icd_add(ptr_instance, &ptr_instance->icd_tramp_list.scanned_list[i]);
        if (NULL == icd_term) {
            loader_log(ptr_instance, VULKAN_LOADER_ERROR_BIT, 0,
                       "terminator_CreateInstance: Failed to add ICD %d to ICD trampoline list.", i);
            res = VK_ERROR_OUT_OF_HOST_MEMORY;
            goto out;
        }

        // If any error happens after here, we need to remove the ICD from the list,
        // because we've already added it, but haven't validated it

        // Make sure that we reset the pApplicationInfo so we don't get an old pointer
        icd_create_info.pApplicationInfo = pCreateInfo->pApplicationInfo;
        icd_create_info.enabledExtensionCount = 0;
        struct loader_extension_list icd_exts;

        // traverse scanned icd list adding non-duplicate extensions to the list
        res = loader_init_generic_list(ptr_instance, (struct loader_generic_list *)&icd_exts, sizeof(VkExtensionProperties));
        if (VK_ERROR_OUT_OF_HOST_MEMORY == res) {
            // If out of memory, bail immediately.
            goto out;
        } else if (VK_SUCCESS != res) {
            // Something bad happened with this ICD, so free it and try the
            // next.
            ptr_instance->icd_terms = icd_term->next;
            icd_term->next = NULL;
            loader_icd_destroy(ptr_instance, icd_term, pAllocator);
            continue;
        }

        res = loader_add_instance_extensions(ptr_instance, icd_term->scanned_icd->EnumerateInstanceExtensionProperties,
                                             icd_term->scanned_icd->lib_name, &icd_exts);
        if (VK_SUCCESS != res) {
            loader_destroy_generic_list(ptr_instance, (struct loader_generic_list *)&icd_exts);
            if (VK_ERROR_OUT_OF_HOST_MEMORY == res) {
                // If out of memory, bail immediately.
                goto out;
            } else {
                // Something bad happened with this ICD, so free it and try the next.
                ptr_instance->icd_terms = icd_term->next;
                icd_term->next = NULL;
                loader_icd_destroy(ptr_instance, icd_term, pAllocator);
                continue;
            }
        }

        for (uint32_t j = 0; j < pCreateInfo->enabledExtensionCount; j++) {
            prop = get_extension_property(pCreateInfo->ppEnabledExtensionNames[j], &icd_exts);
            if (prop) {
                filtered_extension_names[icd_create_info.enabledExtensionCount] = (char *)pCreateInfo->ppEnabledExtensionNames[j];
                icd_create_info.enabledExtensionCount++;
            }
        }
#ifdef LOADER_ENABLE_LINUX_SORT
        // Force on "VK_KHR_get_physical_device_properties2" for Linux as we use it for GPU sorting.  This
        // should be done if the API version of either the application or the driver does not natively support
        // the core version of vkGetPhysicalDeviceProperties2 entrypoint.
        if ((ptr_instance->app_api_version.major == 1 && ptr_instance->app_api_version.minor == 0) ||
            (VK_API_VERSION_MAJOR(icd_term->scanned_icd->api_version) == 1 &&
             VK_API_VERSION_MINOR(icd_term->scanned_icd->api_version) == 0)) {
            prop = get_extension_property(VK_KHR_GET_PHYSICAL_DEVICE_PROPERTIES_2_EXTENSION_NAME, &icd_exts);
            if (prop) {
                filtered_extension_names[icd_create_info.enabledExtensionCount] =
                    (char *)VK_KHR_GET_PHYSICAL_DEVICE_PROPERTIES_2_EXTENSION_NAME;
                icd_create_info.enabledExtensionCount++;

                // At least one ICD supports this, so the instance should be able to support it
                ptr_instance->supports_get_dev_prop_2 = true;
            }
        }
#endif  // LOADER_ENABLE_LINUX_SORT

        // Determine if vkGetPhysicalDeviceProperties2 is available to this Instance
        if (icd_term->scanned_icd->api_version >= VK_API_VERSION_1_1) {
            icd_term->supports_get_dev_prop_2 = true;
        } else {
            for (uint32_t j = 0; j < icd_create_info.enabledExtensionCount; j++) {
                if (!strcmp(filtered_extension_names[j], VK_KHR_GET_PHYSICAL_DEVICE_PROPERTIES_2_EXTENSION_NAME)) {
                    icd_term->supports_get_dev_prop_2 = true;
                    break;
                }
            }
        }

        loader_destroy_generic_list(ptr_instance, (struct loader_generic_list *)&icd_exts);

        // Get the driver version from vkEnumerateInstanceVersion
        uint32_t icd_version = VK_API_VERSION_1_0;
        VkResult icd_result = VK_SUCCESS;
        if (icd_term->scanned_icd->api_version >= VK_API_VERSION_1_1) {
            PFN_vkEnumerateInstanceVersion icd_enumerate_instance_version =
                (PFN_vkEnumerateInstanceVersion)icd_term->scanned_icd->GetInstanceProcAddr(NULL, "vkEnumerateInstanceVersion");
            if (icd_enumerate_instance_version != NULL) {
                icd_result = icd_enumerate_instance_version(&icd_version);
                if (icd_result != VK_SUCCESS) {
                    icd_version = VK_API_VERSION_1_0;
                    loader_log(ptr_instance, VULKAN_LOADER_DEBUG_BIT | VULKAN_LOADER_DRIVER_BIT, 0,
                               "terminator_CreateInstance: ICD \"%s\" vkEnumerateInstanceVersion returned error. The ICD will be "
                               "treated as a 1.0 ICD",
                               icd_term->scanned_icd->lib_name);
                }
            }
        }

        // Remove the portability enumeration flag bit if the ICD doesn't support the extension
        if ((pCreateInfo->flags & VK_INSTANCE_CREATE_ENUMERATE_PORTABILITY_BIT_KHR) == 1) {
            bool supports_portability_enumeration = false;
            for (uint32_t j = 0; j < icd_create_info.enabledExtensionCount; j++) {
                if (strcmp(filtered_extension_names[j], VK_KHR_PORTABILITY_ENUMERATION_EXTENSION_NAME) == 0) {
                    supports_portability_enumeration = true;
                    break;
                }
            }
            // If the icd supports the extension, use the flags as given, otherwise remove the portability bit
            icd_create_info.flags = supports_portability_enumeration
                                        ? pCreateInfo->flags
                                        : pCreateInfo->flags & (~VK_INSTANCE_CREATE_ENUMERATE_PORTABILITY_BIT_KHR);
        }

        // Create an instance, substituting the version to 1.0 if necessary
        VkApplicationInfo icd_app_info;
        uint32_t icd_version_nopatch =
            VK_MAKE_API_VERSION(0, VK_API_VERSION_MAJOR(icd_version), VK_API_VERSION_MINOR(icd_version), 0);
        uint32_t requested_version = (pCreateInfo == NULL || pCreateInfo->pApplicationInfo == NULL)
                                         ? VK_API_VERSION_1_0
                                         : pCreateInfo->pApplicationInfo->apiVersion;
        if ((requested_version != 0) && (icd_version_nopatch == VK_API_VERSION_1_0)) {
            if (icd_create_info.pApplicationInfo == NULL) {
                memset(&icd_app_info, 0, sizeof(icd_app_info));
            } else {
                memmove(&icd_app_info, icd_create_info.pApplicationInfo, sizeof(icd_app_info));
            }
            icd_app_info.apiVersion = icd_version;
            icd_create_info.pApplicationInfo = &icd_app_info;
        }
        icd_result =
            ptr_instance->icd_tramp_list.scanned_list[i].CreateInstance(&icd_create_info, pAllocator, &(icd_term->instance));
        if (VK_ERROR_OUT_OF_HOST_MEMORY == icd_result) {
            // If out of memory, bail immediately.
            res = VK_ERROR_OUT_OF_HOST_MEMORY;
            goto out;
        } else if (VK_SUCCESS != icd_result) {
            loader_log(ptr_instance, VULKAN_LOADER_WARN_BIT, 0,
                       "terminator_CreateInstance: Failed to CreateInstance in ICD %d.  Skipping ICD.", i);
            ptr_instance->icd_terms = icd_term->next;
            icd_term->next = NULL;
            loader_icd_destroy(ptr_instance, icd_term, pAllocator);
            continue;
        }

        if (!loader_icd_init_entries(icd_term, icd_term->instance,
                                     ptr_instance->icd_tramp_list.scanned_list[i].GetInstanceProcAddr)) {
            loader_log(ptr_instance, VULKAN_LOADER_WARN_BIT, 0,
                       "terminator_CreateInstance: Failed to CreateInstance and find entrypoints with ICD.  Skipping ICD.");
            ptr_instance->icd_terms = icd_term->next;
            icd_term->next = NULL;
            loader_icd_destroy(ptr_instance, icd_term, pAllocator);
            continue;
        }

        if (ptr_instance->icd_tramp_list.scanned_list[i].interface_version < 3 &&
            (
#ifdef VK_USE_PLATFORM_XLIB_KHR
                NULL != icd_term->dispatch.CreateXlibSurfaceKHR ||
#endif  // VK_USE_PLATFORM_XLIB_KHR
#ifdef VK_USE_PLATFORM_XCB_KHR
                NULL != icd_term->dispatch.CreateXcbSurfaceKHR ||
#endif  // VK_USE_PLATFORM_XCB_KHR
#ifdef VK_USE_PLATFORM_WAYLAND_KHR
                NULL != icd_term->dispatch.CreateWaylandSurfaceKHR ||
#endif  // VK_USE_PLATFORM_WAYLAND_KHR
#ifdef VK_USE_PLATFORM_ANDROID_KHR
                NULL != icd_term->dispatch.CreateAndroidSurfaceKHR ||
#endif  // VK_USE_PLATFORM_ANDROID_KHR
#ifdef VK_USE_PLATFORM_WIN32_KHR
                NULL != icd_term->dispatch.CreateWin32SurfaceKHR ||
#endif  // VK_USE_PLATFORM_WIN32_KHR
                NULL != icd_term->dispatch.DestroySurfaceKHR)) {
            loader_log(ptr_instance, VULKAN_LOADER_WARN_BIT, 0,
                       "terminator_CreateInstance: Driver %s supports interface version %u but still exposes VkSurfaceKHR"
                       " create/destroy entrypoints (Policy #LDP_DRIVER_8)",
                       ptr_instance->icd_tramp_list.scanned_list[i].lib_name,
                       ptr_instance->icd_tramp_list.scanned_list[i].interface_version);
        }

        // If we made it this far, at least one ICD was successful
        one_icd_successful = true;
    }

    // For vkGetPhysicalDeviceProperties2, at least one ICD needs to support the extension for the
    // instance to have it
    if (ptr_instance->supports_get_dev_prop_2) {
        bool at_least_one_supports = false;
        icd_term = ptr_instance->icd_terms;
        while (icd_term != NULL) {
            if (icd_term->supports_get_dev_prop_2) {
                at_least_one_supports = true;
                break;
            }
            icd_term = icd_term->next;
        }
        if (!at_least_one_supports) {
            ptr_instance->supports_get_dev_prop_2 = false;
        }
    }

    // If no ICDs were added to instance list and res is unchanged from it's initial value, the loader was unable to
    // find a suitable ICD.
    if (VK_SUCCESS == res && (ptr_instance->icd_terms == NULL || !one_icd_successful)) {
        loader_log(ptr_instance, VULKAN_LOADER_ERROR_BIT | VULKAN_LOADER_DRIVER_BIT, 0,
                   "terminator_CreateInstance: Found no drivers!");
        res = VK_ERROR_INCOMPATIBLE_DRIVER;
    }

out:

    ptr_instance->create_terminator_invalid_extension = false;

    if (VK_SUCCESS != res) {
        if (VK_ERROR_EXTENSION_NOT_PRESENT == res) {
            ptr_instance->create_terminator_invalid_extension = true;
        }

        while (NULL != ptr_instance->icd_terms) {
            icd_term = ptr_instance->icd_terms;
            ptr_instance->icd_terms = icd_term->next;
            if (NULL != icd_term->instance) {
                icd_term->dispatch.DestroyInstance(icd_term->instance, pAllocator);
            }
            loader_icd_destroy(ptr_instance, icd_term, pAllocator);
        }
    } else {
        // Check for enabled extensions here to setup the loader structures so the loader knows what extensions
        // it needs to worry about.
        // We do it here and again above the layers in the trampoline function since the trampoline function
        // may think different extensions are enabled than what's down here.
        // This is why we don't clear inside of these function calls.
        // The clearing should actually be handled by the overall memset of the pInstance structure in the
        // trampoline.
        wsi_create_instance(ptr_instance, pCreateInfo);
        check_for_enabled_debug_extensions(ptr_instance, pCreateInfo);
        extensions_create_instance(ptr_instance, pCreateInfo);
    }

    return res;
}

VKAPI_ATTR void VKAPI_CALL terminator_DestroyInstance(VkInstance instance, const VkAllocationCallbacks *pAllocator) {
    struct loader_instance *ptr_instance = loader_get_instance(instance);
    if (NULL == ptr_instance) {
        return;
    }
    struct loader_icd_term *icd_terms = ptr_instance->icd_terms;
    struct loader_icd_term *next_icd_term;

    // Remove this instance from the list of instances:
    struct loader_instance *prev = NULL;
    loader_platform_thread_lock_mutex(&loader_global_instance_list_lock);
    struct loader_instance *next = loader.instances;
    while (next != NULL) {
        if (next == ptr_instance) {
            // Remove this instance from the list:
            if (prev)
                prev->next = next->next;
            else
                loader.instances = next->next;
            break;
        }
        prev = next;
        next = next->next;
    }
    loader_platform_thread_unlock_mutex(&loader_global_instance_list_lock);

    while (NULL != icd_terms) {
        if (icd_terms->instance) {
            icd_terms->dispatch.DestroyInstance(icd_terms->instance, pAllocator);
        }
        next_icd_term = icd_terms->next;
        icd_terms->instance = VK_NULL_HANDLE;
        loader_icd_destroy(ptr_instance, icd_terms, pAllocator);

        icd_terms = next_icd_term;
    }

    loader_delete_layer_list_and_properties(ptr_instance, &ptr_instance->instance_layer_list);
    loader_scanned_icd_clear(ptr_instance, &ptr_instance->icd_tramp_list);
    loader_destroy_generic_list(ptr_instance, (struct loader_generic_list *)&ptr_instance->ext_list);
    if (NULL != ptr_instance->phys_devs_term) {
        for (uint32_t i = 0; i < ptr_instance->phys_dev_count_term; i++) {
            for (uint32_t j = i + 1; j < ptr_instance->phys_dev_count_term; j++) {
                if (ptr_instance->phys_devs_term[i] == ptr_instance->phys_devs_term[j]) {
                    ptr_instance->phys_devs_term[j] = NULL;
                }
            }
        }
        for (uint32_t i = 0; i < ptr_instance->phys_dev_count_term; i++) {
            loader_instance_heap_free(ptr_instance, ptr_instance->phys_devs_term[i]);
        }
        loader_instance_heap_free(ptr_instance, ptr_instance->phys_devs_term);
    }
    if (NULL != ptr_instance->phys_dev_groups_term) {
        for (uint32_t i = 0; i < ptr_instance->phys_dev_group_count_term; i++) {
            loader_instance_heap_free(ptr_instance, ptr_instance->phys_dev_groups_term[i]);
        }
        loader_instance_heap_free(ptr_instance, ptr_instance->phys_dev_groups_term);
    }
    loader_free_dev_ext_table(ptr_instance);
    loader_free_phys_dev_ext_table(ptr_instance);

    for (uint32_t i = 0, n = ptr_instance->enabled_layer_count; i < n; ++i) {
        loader_instance_heap_free(ptr_instance, ptr_instance->enabled_layer_names[i]);
    }

    if (ptr_instance->enabled_layer_count > 0) {
        loader_instance_heap_free(ptr_instance, ptr_instance->enabled_layer_names);
        memset(&ptr_instance->enabled_layer_names, 0, sizeof(ptr_instance->enabled_layer_names));
    }
}

VKAPI_ATTR VkResult VKAPI_CALL terminator_CreateDevice(VkPhysicalDevice physicalDevice, const VkDeviceCreateInfo *pCreateInfo,
                                                       const VkAllocationCallbacks *pAllocator, VkDevice *pDevice) {
    VkResult res = VK_SUCCESS;
    struct loader_physical_device_term *phys_dev_term;
    phys_dev_term = (struct loader_physical_device_term *)physicalDevice;
    struct loader_icd_term *icd_term = phys_dev_term->this_icd_term;

    struct loader_device *dev = (struct loader_device *)*pDevice;
    PFN_vkCreateDevice fpCreateDevice = icd_term->dispatch.CreateDevice;
    struct loader_extension_list icd_exts;

    VkBaseOutStructure *caller_dgci_container = NULL;
    VkDeviceGroupDeviceCreateInfoKHR *caller_dgci = NULL;

    dev->phys_dev_term = phys_dev_term;

    icd_exts.list = NULL;

    if (fpCreateDevice == NULL) {
        loader_log(icd_term->this_instance, VULKAN_LOADER_ERROR_BIT | VULKAN_LOADER_DRIVER_BIT, 0,
                   "terminator_CreateDevice: No vkCreateDevice command exposed by ICD %s", icd_term->scanned_icd->lib_name);
        res = VK_ERROR_INITIALIZATION_FAILED;
        goto out;
    }

    VkDeviceCreateInfo localCreateInfo;
    memcpy(&localCreateInfo, pCreateInfo, sizeof(localCreateInfo));

    // NOTE: Need to filter the extensions to only those supported by the ICD.
    //       No ICD will advertise support for layers. An ICD library could support a layer,
    //       but it would be independent of the actual ICD, just in the same library.
    char **filtered_extension_names = NULL;
    if (0 < pCreateInfo->enabledExtensionCount) {
        filtered_extension_names = loader_stack_alloc(pCreateInfo->enabledExtensionCount * sizeof(char *));
        if (NULL == filtered_extension_names) {
            loader_log(icd_term->this_instance, VULKAN_LOADER_ERROR_BIT, 0,
                       "terminator_CreateDevice: Failed to create extension name storage for %d extensions",
                       pCreateInfo->enabledExtensionCount);
            return VK_ERROR_OUT_OF_HOST_MEMORY;
        }
    }

    localCreateInfo.enabledLayerCount = 0;
    localCreateInfo.ppEnabledLayerNames = NULL;

    localCreateInfo.enabledExtensionCount = 0;
    localCreateInfo.ppEnabledExtensionNames = (const char *const *)filtered_extension_names;

    // Get the physical device (ICD) extensions
    res = loader_init_generic_list(icd_term->this_instance, (struct loader_generic_list *)&icd_exts, sizeof(VkExtensionProperties));
    if (VK_SUCCESS != res) {
        goto out;
    }

    res = loader_add_device_extensions(icd_term->this_instance, icd_term->dispatch.EnumerateDeviceExtensionProperties,
                                       phys_dev_term->phys_dev, icd_term->scanned_icd->lib_name, &icd_exts);
    if (res != VK_SUCCESS) {
        goto out;
    }

    for (uint32_t i = 0; i < pCreateInfo->enabledExtensionCount; i++) {
        const char *extension_name = pCreateInfo->ppEnabledExtensionNames[i];
        VkExtensionProperties *prop = get_extension_property(extension_name, &icd_exts);
        if (prop) {
            filtered_extension_names[localCreateInfo.enabledExtensionCount] = (char *)extension_name;
            localCreateInfo.enabledExtensionCount++;
        } else {
            loader_log(icd_term->this_instance, VULKAN_LOADER_DEBUG_BIT | VULKAN_LOADER_DRIVER_BIT, 0,
                       "vkCreateDevice extension %s not available for devices associated with ICD %s", extension_name,
                       icd_term->scanned_icd->lib_name);
        }
    }

    // Before we continue, If KHX_device_group is the list of enabled and viable extensions, then we then need to look for the
    // corresponding VkDeviceGroupDeviceCreateInfo struct in the device list and replace all the physical device values (which
    // are really loader physical device terminator values) with the ICD versions.
    // if (icd_term->this_instance->enabled_known_extensions.khr_device_group_creation == 1) {
    {
        VkBaseOutStructure *pNext = (VkBaseOutStructure *)localCreateInfo.pNext;
        VkBaseOutStructure *pPrev = (VkBaseOutStructure *)&localCreateInfo;
        while (NULL != pNext) {
            if (VK_STRUCTURE_TYPE_DEVICE_GROUP_DEVICE_CREATE_INFO == pNext->sType) {
                VkDeviceGroupDeviceCreateInfo *cur_struct = (VkDeviceGroupDeviceCreateInfo *)pNext;
                if (0 < cur_struct->physicalDeviceCount && NULL != cur_struct->pPhysicalDevices) {
                    VkDeviceGroupDeviceCreateInfo *temp_struct = loader_stack_alloc(sizeof(VkDeviceGroupDeviceCreateInfo));
                    VkPhysicalDevice *phys_dev_array = NULL;
                    if (NULL == temp_struct) {
                        return VK_ERROR_OUT_OF_HOST_MEMORY;
                    }
                    memcpy(temp_struct, cur_struct, sizeof(VkDeviceGroupDeviceCreateInfo));
                    phys_dev_array = loader_stack_alloc(sizeof(VkPhysicalDevice) * cur_struct->physicalDeviceCount);
                    if (NULL == phys_dev_array) {
                        return VK_ERROR_OUT_OF_HOST_MEMORY;
                    }

                    // Before calling down, replace the incoming physical device values (which are really loader terminator
                    // physical devices) with the ICDs physical device values.
                    struct loader_physical_device_term *cur_term;
                    for (uint32_t phys_dev = 0; phys_dev < cur_struct->physicalDeviceCount; phys_dev++) {
                        cur_term = (struct loader_physical_device_term *)cur_struct->pPhysicalDevices[phys_dev];
                        phys_dev_array[phys_dev] = cur_term->phys_dev;
                    }
                    temp_struct->pPhysicalDevices = phys_dev_array;

                    // Keep track of pointers to restore pNext chain before returning
                    caller_dgci_container = pPrev;
                    caller_dgci = cur_struct;

                    // Replace the old struct in the pNext chain with this one.
                    pPrev->pNext = (VkBaseOutStructure *)temp_struct;
                }
                break;
            }

            pPrev = pNext;
            pNext = pNext->pNext;
        }
    }

    // Handle loader emulation for structs that are not supported by the ICD:
    // Presently, the emulation leaves the pNext chain alone. This means that the ICD will receive items in the chain which
    // are not recognized by the ICD. If this causes the ICD to fail, then the items would have to be removed here. The current
    // implementation does not remove them because copying the pNext chain would be impossible if the loader does not recognize
    // the any of the struct types, as the loader would not know the size to allocate and copy.
    // if (icd_term->dispatch.GetPhysicalDeviceFeatures2 == NULL && icd_term->dispatch.GetPhysicalDeviceFeatures2KHR == NULL) {
    {
        const void *pNext = localCreateInfo.pNext;
        while (pNext != NULL) {
            switch (*(VkStructureType *)pNext) {
                case VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_FEATURES_2: {
                    const VkPhysicalDeviceFeatures2KHR *features = pNext;

                    if (icd_term->dispatch.GetPhysicalDeviceFeatures2 == NULL &&
                        icd_term->dispatch.GetPhysicalDeviceFeatures2KHR == NULL) {
                        loader_log(icd_term->this_instance, VULKAN_LOADER_INFO_BIT, 0,
                                   "vkCreateDevice: Emulating handling of VkPhysicalDeviceFeatures2 in pNext chain for ICD \"%s\"",
                                   icd_term->scanned_icd->lib_name);

                        // Verify that VK_KHR_get_physical_device_properties2 is enabled
                        if (icd_term->this_instance->enabled_known_extensions.khr_get_physical_device_properties2) {
                            localCreateInfo.pEnabledFeatures = &features->features;
                        }
                    }

                    // Leave this item in the pNext chain for now

                    pNext = features->pNext;
                    break;
                }

                case VK_STRUCTURE_TYPE_DEVICE_GROUP_DEVICE_CREATE_INFO: {
                    const VkDeviceGroupDeviceCreateInfoKHR *group_info = pNext;

                    if (icd_term->dispatch.EnumeratePhysicalDeviceGroups == NULL &&
                        icd_term->dispatch.EnumeratePhysicalDeviceGroupsKHR == NULL) {
                        loader_log(icd_term->this_instance, VULKAN_LOADER_INFO_BIT, 0,
                                   "vkCreateDevice: Emulating handling of VkPhysicalDeviceGroupProperties in pNext chain for "
                                   "ICD \"%s\"",
                                   icd_term->scanned_icd->lib_name);

                        // The group must contain only this one device, since physical device groups aren't actually supported
                        if (group_info->physicalDeviceCount != 1) {
                            loader_log(icd_term->this_instance, VULKAN_LOADER_ERROR_BIT, 0,
                                       "vkCreateDevice: Emulation failed to create device from device group info");
                            res = VK_ERROR_INITIALIZATION_FAILED;
                            goto out;
                        }
                    }

                    // Nothing needs to be done here because we're leaving the item in the pNext chain and because the spec
                    // states that the physicalDevice argument must be included in the device group, and we've already checked
                    // that it is

                    pNext = group_info->pNext;
                    break;
                }

                // Multiview properties are also allowed, but since VK_KHX_multiview is a device extension, we'll just let the
                // ICD handle that error when the user enables the extension here
                default: {
                    const VkBaseInStructure *header = pNext;
                    pNext = header->pNext;
                    break;
                }
            }
        }
    }

    // Every extension that has a loader-defined terminator needs to be marked as enabled or disabled so that we know whether or
    // not to return that terminator when vkGetDeviceProcAddr is called
    for (uint32_t i = 0; i < localCreateInfo.enabledExtensionCount; ++i) {
        if (!strcmp(localCreateInfo.ppEnabledExtensionNames[i], VK_KHR_SWAPCHAIN_EXTENSION_NAME)) {
            dev->extensions.khr_swapchain_enabled = true;
        } else if (!strcmp(localCreateInfo.ppEnabledExtensionNames[i], VK_KHR_DISPLAY_SWAPCHAIN_EXTENSION_NAME)) {
            dev->extensions.khr_display_swapchain_enabled = true;
        } else if (!strcmp(localCreateInfo.ppEnabledExtensionNames[i], VK_KHR_DEVICE_GROUP_EXTENSION_NAME)) {
            dev->extensions.khr_device_group_enabled = true;
        } else if (!strcmp(localCreateInfo.ppEnabledExtensionNames[i], VK_EXT_DEBUG_MARKER_EXTENSION_NAME)) {
            dev->extensions.ext_debug_marker_enabled = true;
        } else if (!strcmp(localCreateInfo.ppEnabledExtensionNames[i], "VK_EXT_full_screen_exclusive")) {
            dev->extensions.ext_full_screen_exclusive_enabled = true;
        }
    }
    dev->extensions.ext_debug_utils_enabled = icd_term->this_instance->enabled_known_extensions.ext_debug_utils;

    VkPhysicalDeviceProperties properties;
    icd_term->dispatch.GetPhysicalDeviceProperties(phys_dev_term->phys_dev, &properties);
    if (!dev->extensions.khr_device_group_enabled) {
        if (properties.apiVersion >= VK_API_VERSION_1_1) {
            dev->extensions.khr_device_group_enabled = true;
        }
    }

    loader_log(icd_term->this_instance, VULKAN_LOADER_LAYER_BIT | VULKAN_LOADER_DRIVER_BIT, 0,
               "       Using \"%s\" with driver: \"%s\"", properties.deviceName, icd_term->scanned_icd->lib_name);

    res = fpCreateDevice(phys_dev_term->phys_dev, &localCreateInfo, pAllocator, &dev->icd_device);
    if (res != VK_SUCCESS) {
        loader_log(icd_term->this_instance, VULKAN_LOADER_ERROR_BIT | VULKAN_LOADER_DRIVER_BIT, 0,
                   "terminator_CreateDevice: Failed in ICD %s vkCreateDevice call", icd_term->scanned_icd->lib_name);
        goto out;
    }

    *pDevice = dev->icd_device;
    loader_add_logical_device(icd_term->this_instance, icd_term, dev);

    // Init dispatch pointer in new device object
    loader_init_dispatch(*pDevice, &dev->loader_dispatch);

out:
    if (NULL != icd_exts.list) {
        loader_destroy_generic_list(icd_term->this_instance, (struct loader_generic_list *)&icd_exts);
    }

    // Restore pNext pointer to old VkDeviceGroupDeviceCreateInfoKHX
    // in the chain to maintain consistency for the caller.
    if (caller_dgci_container != NULL) {
        caller_dgci_container->pNext = (VkBaseOutStructure *)caller_dgci;
    }

    return res;
}

// Update the trampoline physical devices with the wrapped version.
// We always want to re-use previous physical device pointers since they may be used by an application
// after returning previously.
VkResult setup_loader_tramp_phys_devs(struct loader_instance *inst, uint32_t phys_dev_count, VkPhysicalDevice *phys_devs) {
    VkResult res = VK_SUCCESS;
    uint32_t found_count = 0;
    uint32_t old_count = inst->phys_dev_count_tramp;
    uint32_t new_count = inst->total_gpu_count;
    struct loader_physical_device_tramp **new_phys_devs = NULL;

    if (0 == phys_dev_count) {
        return VK_SUCCESS;
    }
    if (phys_dev_count > new_count) {
        new_count = phys_dev_count;
    }

    // We want an old to new index array and a new to old index array
    int32_t *old_to_new_index = (int32_t *)loader_stack_alloc(sizeof(int32_t) * old_count);
    int32_t *new_to_old_index = (int32_t *)loader_stack_alloc(sizeof(int32_t) * new_count);
    if (NULL == old_to_new_index || NULL == new_to_old_index) {
        return VK_ERROR_OUT_OF_HOST_MEMORY;
    }

    // Initialize both
    for (uint32_t cur_idx = 0; cur_idx < old_count; ++cur_idx) {
        old_to_new_index[cur_idx] = -1;
    }
    for (uint32_t cur_idx = 0; cur_idx < new_count; ++cur_idx) {
        new_to_old_index[cur_idx] = -1;
    }

    // Figure out the old->new and new->old indices
    for (uint32_t cur_idx = 0; cur_idx < old_count; ++cur_idx) {
        for (uint32_t new_idx = 0; new_idx < phys_dev_count; ++new_idx) {
            if (inst->phys_devs_tramp[cur_idx]->phys_dev == phys_devs[new_idx]) {
                old_to_new_index[cur_idx] = (int32_t)new_idx;
                new_to_old_index[new_idx] = (int32_t)cur_idx;
                found_count++;
                break;
            }
        }
    }

    // If we found exactly the number of items we were looking for as we had before.  Then everything
    // we already have is good enough and we just need to update the array that was passed in with
    // the loader values.
    if (found_count == phys_dev_count && 0 != old_count && old_count == new_count) {
        for (uint32_t new_idx = 0; new_idx < phys_dev_count; ++new_idx) {
            for (uint32_t cur_idx = 0; cur_idx < old_count; ++cur_idx) {
                if (old_to_new_index[cur_idx] == (int32_t)new_idx) {
                    phys_devs[new_idx] = (VkPhysicalDevice)inst->phys_devs_tramp[cur_idx];
                    break;
                }
            }
        }
        // Nothing else to do for this path
        res = VK_SUCCESS;
    } else {
        // Something is different, so do the full path of checking every device and creating a new array to use.
        // This can happen if a device was added, or removed, or we hadn't previously queried all the data and we
        // have more to store.
        new_phys_devs = loader_instance_heap_calloc(inst, sizeof(struct loader_physical_device_tramp *) * new_count,
                                                    VK_SYSTEM_ALLOCATION_SCOPE_INSTANCE);
        if (NULL == new_phys_devs) {
            loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                       "setup_loader_tramp_phys_devs:  Failed to allocate new physical device array of size %d", new_count);
            res = VK_ERROR_OUT_OF_HOST_MEMORY;
            goto out;
        }

        if (new_count > phys_dev_count) {
            found_count = phys_dev_count;
        } else {
            found_count = new_count;
        }

        // First try to see if an old item exists that matches the new item.  If so, just copy it over.
        for (uint32_t new_idx = 0; new_idx < found_count; ++new_idx) {
            bool old_item_found = false;
            for (uint32_t cur_idx = 0; cur_idx < old_count; ++cur_idx) {
                if (old_to_new_index[cur_idx] == (int32_t)new_idx) {
                    // Copy over old item to correct spot in the new array
                    new_phys_devs[new_idx] = inst->phys_devs_tramp[cur_idx];
                    old_item_found = true;
                    break;
                }
            }
            // Something wasn't found, so it's new so add it to the new list
            if (!old_item_found) {
                new_phys_devs[new_idx] = loader_instance_heap_alloc(inst, sizeof(struct loader_physical_device_tramp),
                                                                    VK_SYSTEM_ALLOCATION_SCOPE_INSTANCE);
                if (NULL == new_phys_devs[new_idx]) {
                    loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                               "setup_loader_tramp_phys_devs:  Failed to allocate new trampoline physical device");
                    res = VK_ERROR_OUT_OF_HOST_MEMORY;
                    goto out;
                }

                // Initialize the new physicalDevice object
                loader_set_dispatch((void *)new_phys_devs[new_idx], inst->disp);
                new_phys_devs[new_idx]->this_instance = inst;
                new_phys_devs[new_idx]->phys_dev = phys_devs[new_idx];
                new_phys_devs[new_idx]->magic = PHYS_TRAMP_MAGIC_NUMBER;
            }

            phys_devs[new_idx] = (VkPhysicalDevice)new_phys_devs[new_idx];
        }

        // We usually get here if the user array is smaller than the total number of devices, so copy the
        // remaining devices we have over to the new array.
        uint32_t start = found_count;
        for (uint32_t new_idx = start; new_idx < new_count; ++new_idx) {
            for (uint32_t cur_idx = 0; cur_idx < old_count; ++cur_idx) {
                if (old_to_new_index[cur_idx] == -1) {
                    new_phys_devs[new_idx] = inst->phys_devs_tramp[cur_idx];
                    old_to_new_index[cur_idx] = new_idx;
                    found_count++;
                    break;
                }
            }
        }
    }

out:

    if (NULL != new_phys_devs) {
        if (VK_SUCCESS != res) {
            for (uint32_t new_idx = 0; new_idx < found_count; ++new_idx) {
                // If an OOM occurred inside the copying of the new physical devices into the existing array
                // will leave some of the old physical devices in the array which may have been copied into
                // the new array, leading to them being freed twice. To avoid this we just make sure to not
                // delete physical devices which were copied.
                bool found = false;
                for (uint32_t cur_idx = 0; cur_idx < inst->phys_dev_count_tramp; cur_idx++) {
                    if (new_phys_devs[new_idx] == inst->phys_devs_tramp[cur_idx]) {
                        found = true;
                        break;
                    }
                }
                if (!found) {
                    loader_instance_heap_free(inst, new_phys_devs[new_idx]);
                }
            }
            loader_instance_heap_free(inst, new_phys_devs);
        } else {
            if (new_count > inst->total_gpu_count) {
                inst->total_gpu_count = new_count;
            }
            // Free everything in the old array that was not copied into the new array
            // here.  We can't attempt to do that before here since the previous loop
            // looking before the "out:" label may hit an out of memory condition resulting
            // in memory leaking.
            if (NULL != inst->phys_devs_tramp) {
                for (uint32_t i = 0; i < inst->phys_dev_count_tramp; i++) {
                    bool found = false;
                    for (uint32_t j = 0; j < inst->total_gpu_count; j++) {
                        if (inst->phys_devs_tramp[i] == new_phys_devs[j]) {
                            found = true;
                            break;
                        }
                    }
                    if (!found) {
                        loader_instance_heap_free(inst, inst->phys_devs_tramp[i]);
                    }
                }
                loader_instance_heap_free(inst, inst->phys_devs_tramp);
            }
            inst->phys_devs_tramp = new_phys_devs;
            inst->phys_dev_count_tramp = found_count;
        }
    }
    if (VK_SUCCESS != res) {
        inst->total_gpu_count = 0;
    }

    return res;
}

#ifdef LOADER_ENABLE_LINUX_SORT
bool is_linux_sort_enabled(struct loader_instance *inst) {
    bool sort_items = inst->supports_get_dev_prop_2;
    char *env_value = loader_getenv("VK_LOADER_DISABLE_SELECT", inst);
    if (NULL != env_value) {
        int32_t int_env_val = atoi(env_value);
        loader_free_getenv(env_value, inst);
        if (int_env_val != 0) {
            sort_items = false;
        }
    }
    return sort_items;
}
#endif  // LOADER_ENABLE_LINUX_SORT

// Look for physical_device in the provided phys_devs list, return true if found and put the index into out_idx, otherwise
// return false
bool find_phys_dev(VkPhysicalDevice physical_device, uint32_t phys_devs_count, struct loader_physical_device_term **phys_devs,
                   uint32_t *out_idx) {
    if (NULL == phys_devs) return false;
    for (uint32_t idx = 0; idx < phys_devs_count; idx++) {
        if (NULL != phys_devs[idx] && physical_device == phys_devs[idx]->phys_dev) {
            *out_idx = idx;
            return true;
        }
    }
    return false;
}

// Add physical_device to new_phys_devs
VkResult check_and_add_to_new_phys_devs(struct loader_instance *inst, VkPhysicalDevice physical_device,
                                        struct loader_phys_dev_per_icd *dev_array, uint32_t *cur_new_phys_dev_count,
                                        struct loader_physical_device_term **new_phys_devs) {
    uint32_t out_idx = 0;
    uint32_t idx = *cur_new_phys_dev_count;
    // Check if the physical_device already exists in the new_phys_devs buffer, that means it was found from both
    // EnumerateAdapterPhysicalDevices and EnumeratePhysicalDevices and we need to skip it.
    if (find_phys_dev(physical_device, idx, new_phys_devs, &out_idx)) {
        return VK_SUCCESS;
    }
    // Check if it was found in a previous call to vkEnumeratePhysicalDevices, we can just copy over the old data.
    if (find_phys_dev(physical_device, inst->phys_dev_count_term, inst->phys_devs_term, &out_idx)) {
        new_phys_devs[idx] = inst->phys_devs_term[out_idx];
        (*cur_new_phys_dev_count)++;
        return VK_SUCCESS;
    }

    // Exit in case something is already present - this shouldn't happen but better to be safe than overwrite existing data
    // since this code has been refactored a half dozen times.
    if (NULL != new_phys_devs[idx]) {
        return VK_SUCCESS;
    }
    // If this physical device is new, we need to allocate space for it.
    new_phys_devs[idx] =
        loader_instance_heap_alloc(inst, sizeof(struct loader_physical_device_term), VK_SYSTEM_ALLOCATION_SCOPE_INSTANCE);
    if (NULL == new_phys_devs[idx]) {
        loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                   "check_and_add_to_new_phys_devs:  Failed to allocate physical device terminator object %d", idx);
        return VK_ERROR_OUT_OF_HOST_MEMORY;
    }

    loader_set_dispatch((void *)new_phys_devs[idx], inst->disp);
    new_phys_devs[idx]->this_icd_term = dev_array->icd_term;
    new_phys_devs[idx]->icd_index = (uint8_t)(dev_array->icd_index);
    new_phys_devs[idx]->phys_dev = physical_device;

    // Increment the count of new physical devices
    (*cur_new_phys_dev_count)++;
    return VK_SUCCESS;
}

/* Enumerate all physical devices from ICDs and add them to inst->phys_devs_term
 *
 * There are two methods to find VkPhysicalDevices - vkEnumeratePhysicalDevices and vkEnumerateAdapterPhysicalDevices
 * The latter is supported on windows only and on devices supporting ICD Interface Version 6 and greater.
 *
 * Once all physical devices are acquired, they need to be pulled into a single list of `loader_physical_device_term`'s.
 * They also need to be setup - the icd_term, icd_index, phys_dev, and disp (dispatch table) all need the correct data.
 * Additionally, we need to keep using already setup physical devices as they may be in use, thus anything enumerated
 * that is already in inst->phys_devs_term will be carried over.
 */

VkResult setup_loader_term_phys_devs(struct loader_instance *inst) {
    VkResult res = VK_SUCCESS;
    struct loader_icd_term *icd_term;
    uint32_t icd_idx = 0;
    uint32_t windows_sorted_devices_count = 0;
    struct loader_phys_dev_per_icd *windows_sorted_devices_array = NULL;
    uint32_t icd_count = 0;
    struct loader_phys_dev_per_icd *icd_phys_dev_array = NULL;
    uint32_t new_phys_devs_capacity = 0;
    uint32_t new_phys_devs_count = 0;
    struct loader_physical_device_term **new_phys_devs = NULL;

#if defined(_WIN32)
    // Get the physical devices supported by platform sorting mechanism into a separate list
    res = windows_read_sorted_physical_devices(inst, &windows_sorted_devices_count, &windows_sorted_devices_array);
    if (VK_SUCCESS != res) {
        goto out;
    }
#endif

    icd_count = inst->total_icd_count;

    // Allocate something to store the physical device characteristics that we read from each ICD.
    icd_phys_dev_array = (struct loader_phys_dev_per_icd *)loader_stack_alloc(sizeof(struct loader_phys_dev_per_icd) * icd_count);
    if (NULL == icd_phys_dev_array) {
        loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                   "setup_loader_term_phys_devs:  Failed to allocate temporary ICD Physical device info array of size %d",
                   icd_count);
        res = VK_ERROR_OUT_OF_HOST_MEMORY;
        goto out;
    }
    memset(icd_phys_dev_array, 0, sizeof(struct loader_phys_dev_per_icd) * icd_count);

    // For each ICD, query the number of physical devices, and then get an
    // internal value for those physical devices.
    icd_term = inst->icd_terms;
    while (NULL != icd_term) {
        res = icd_term->dispatch.EnumeratePhysicalDevices(icd_term->instance, &icd_phys_dev_array[icd_idx].device_count, NULL);
        if (VK_SUCCESS != res) {
            loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                       "setup_loader_term_phys_devs:  Call to ICD %d's \'vkEnumeratePhysicalDevices\' failed with error 0x%08x",
                       icd_idx, res);
            goto out;
        }

        icd_phys_dev_array[icd_idx].physical_devices =
            (VkPhysicalDevice *)loader_stack_alloc(icd_phys_dev_array[icd_idx].device_count * sizeof(VkPhysicalDevice));
        if (NULL == icd_phys_dev_array[icd_idx].physical_devices) {
            loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                       "setup_loader_term_phys_devs:  Failed to allocate temporary ICD Physical device array for ICD %d of size %d",
                       icd_idx, icd_phys_dev_array[icd_idx].device_count);
            res = VK_ERROR_OUT_OF_HOST_MEMORY;
            goto out;
        }

        res = icd_term->dispatch.EnumeratePhysicalDevices(icd_term->instance, &(icd_phys_dev_array[icd_idx].device_count),
                                                          icd_phys_dev_array[icd_idx].physical_devices);
        if (VK_SUCCESS != res) {
            goto out;
        }
        icd_phys_dev_array[icd_idx].icd_term = icd_term;
        icd_phys_dev_array[icd_idx].icd_index = icd_idx;
        icd_term = icd_term->next;
        ++icd_idx;
    }

    // Add up both the windows sorted and non windows found physical device counts
    for (uint32_t i = 0; i < windows_sorted_devices_count; ++i) {
        new_phys_devs_capacity += windows_sorted_devices_array[i].device_count;
    }
    for (uint32_t i = 0; i < icd_count; ++i) {
        new_phys_devs_capacity += icd_phys_dev_array[i].device_count;
    }

    // Bail out if there are no physical devices reported
    if (0 == new_phys_devs_capacity) {
        loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                   "setup_loader_term_phys_devs:  Failed to detect any valid GPUs in the current config");
        res = VK_ERROR_INITIALIZATION_FAILED;
        goto out;
    }

    // Create an allocation large enough to hold both the windows sorting enumeration and non-windows physical device
    // enumeration
    new_phys_devs = loader_instance_heap_calloc(inst, sizeof(struct loader_physical_device_term *) * new_phys_devs_capacity,
                                                VK_SYSTEM_ALLOCATION_SCOPE_INSTANCE);
    if (NULL == new_phys_devs) {
        loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                   "setup_loader_term_phys_devs:  Failed to allocate new physical device array of size %d", new_phys_devs_capacity);
        res = VK_ERROR_OUT_OF_HOST_MEMORY;
        goto out;
    }

    // Copy over everything found through sorted enumeration
    for (uint32_t i = 0; i < windows_sorted_devices_count; ++i) {
        for (uint32_t j = 0; j < windows_sorted_devices_array[i].device_count; ++j) {
            res = check_and_add_to_new_phys_devs(inst, windows_sorted_devices_array[i].physical_devices[j],
                                                 &windows_sorted_devices_array[i], &new_phys_devs_count, new_phys_devs);
            if (res == VK_ERROR_OUT_OF_HOST_MEMORY) {
                goto out;
            }
        }
    }

    // Now go through the rest of the physical devices and add them to new_phys_devs
#ifdef LOADER_ENABLE_LINUX_SORT

    if (is_linux_sort_enabled(inst)) {
        for (uint32_t dev = new_phys_devs_count; dev < new_phys_devs_capacity; ++dev) {
            new_phys_devs[dev] =
                loader_instance_heap_alloc(inst, sizeof(struct loader_physical_device_term), VK_SYSTEM_ALLOCATION_SCOPE_INSTANCE);
            if (NULL == new_phys_devs[dev]) {
                loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                           "setup_loader_term_phys_devs:  Failed to allocate physical device terminator object %d", dev);
                res = VK_ERROR_OUT_OF_HOST_MEMORY;
                goto out;
            }
        }

        // Get the physical devices supported by platform sorting mechanism into a separate list
        // Pass in a sublist to the function so it only operates on the correct elements. This means passing in a pointer to the
        // current next element in new_phys_devs and passing in a `count` of currently unwritten elements
        res = linux_read_sorted_physical_devices(inst, icd_count, icd_phys_dev_array, new_phys_devs_capacity - new_phys_devs_count,
                                                 &new_phys_devs[new_phys_devs_count]);
        if (res == VK_ERROR_OUT_OF_HOST_MEMORY) {
            goto out;
        }
        // Keep previously allocated physical device info since apps may already be using that!
        for (uint32_t new_idx = new_phys_devs_count; new_idx < new_phys_devs_capacity; new_idx++) {
            for (uint32_t old_idx = 0; old_idx < inst->phys_dev_count_term; old_idx++) {
                if (new_phys_devs[new_idx]->phys_dev == inst->phys_devs_term[old_idx]->phys_dev) {
                    loader_log(inst, VULKAN_LOADER_DEBUG_BIT | VULKAN_LOADER_DRIVER_BIT, 0,
                               "Copying old device %u into new device %u", old_idx, new_idx);
                    // Free the old new_phys_devs info since we're not using it before we assign the new info
                    loader_instance_heap_free(inst, new_phys_devs[new_idx]);
                    new_phys_devs[new_idx] = inst->phys_devs_term[old_idx];
                    break;
                }
            }
        }
        // now set the count to the capacity, as now the list is filled in
        new_phys_devs_count = new_phys_devs_capacity;
        // We want the following code to run if either linux sorting is disabled at compile time or runtime
    } else {
#endif  // LOADER_ENABLE_LINUX_SORT

        // Copy over everything found through the non-sorted means.
        for (uint32_t i = 0; i < icd_count; ++i) {
            for (uint32_t j = 0; j < icd_phys_dev_array[i].device_count; ++j) {
                res = check_and_add_to_new_phys_devs(inst, icd_phys_dev_array[i].physical_devices[j], &icd_phys_dev_array[i],
                                                     &new_phys_devs_count, new_phys_devs);
                if (res == VK_ERROR_OUT_OF_HOST_MEMORY) {
                    goto out;
                }
            }
        }
#ifdef LOADER_ENABLE_LINUX_SORT
    }
#endif  // LOADER_ENABLE_LINUX_SORT
out:

    if (VK_SUCCESS != res) {
        if (NULL != new_phys_devs) {
            // We've encountered an error, so we should free the new buffers.
            for (uint32_t i = 0; i < new_phys_devs_capacity; i++) {
                // May not have allocated this far, skip it if we hadn't.
                if (new_phys_devs[i] == NULL) continue;

                // If an OOM occurred inside the copying of the new physical devices into the existing array
                // will leave some of the old physical devices in the array which may have been copied into
                // the new array, leading to them being freed twice. To avoid this we just make sure to not
                // delete physical devices which were copied.
                bool found = false;
                if (NULL != inst->phys_devs_term) {
                    for (uint32_t old_idx = 0; old_idx < inst->phys_dev_count_term; old_idx++) {
                        if (new_phys_devs[i] == inst->phys_devs_term[old_idx]) {
                            found = true;
                            break;
                        }
                    }
                }
                if (!found) {
                    loader_instance_heap_free(inst, new_phys_devs[i]);
                }
            }
            loader_instance_heap_free(inst, new_phys_devs);
        }
        inst->total_gpu_count = 0;
    } else {
        if (NULL != inst->phys_devs_term) {
            // Free everything in the old array that was not copied into the new array
            // here.  We can't attempt to do that before here since the previous loop
            // looking before the "out:" label may hit an out of memory condition resulting
            // in memory leaking.
            for (uint32_t i = 0; i < inst->phys_dev_count_term; i++) {
                bool found = false;
                for (uint32_t j = 0; j < new_phys_devs_count; j++) {
                    if (new_phys_devs != NULL && inst->phys_devs_term[i] == new_phys_devs[j]) {
                        found = true;
                        break;
                    }
                }
                if (!found) {
                    loader_instance_heap_free(inst, inst->phys_devs_term[i]);
                }
            }
            loader_instance_heap_free(inst, inst->phys_devs_term);
        }

        // Swap out old and new devices list
        inst->phys_dev_count_term = new_phys_devs_count;
        inst->phys_devs_term = new_phys_devs;
        inst->total_gpu_count = new_phys_devs_count;
    }

    if (windows_sorted_devices_array != NULL) {
        for (uint32_t i = 0; i < windows_sorted_devices_count; ++i) {
            if (windows_sorted_devices_array[i].device_count > 0 && windows_sorted_devices_array[i].physical_devices != NULL) {
                loader_instance_heap_free(inst, windows_sorted_devices_array[i].physical_devices);
            }
        }
        loader_instance_heap_free(inst, windows_sorted_devices_array);
    }

    return res;
}

VkResult setup_loader_tramp_phys_dev_groups(struct loader_instance *inst, uint32_t group_count,
                                            VkPhysicalDeviceGroupProperties *groups) {
    VkResult res = VK_SUCCESS;
    uint32_t cur_idx;
    uint32_t dev_idx;

    if (0 == group_count) {
        return VK_SUCCESS;
    }

    // Generate a list of all the devices and convert them to the loader ID
    uint32_t phys_dev_count = 0;
    for (cur_idx = 0; cur_idx < group_count; ++cur_idx) {
        phys_dev_count += groups[cur_idx].physicalDeviceCount;
    }
    VkPhysicalDevice *devices = (VkPhysicalDevice *)loader_stack_alloc(sizeof(VkPhysicalDevice) * phys_dev_count);
    if (NULL == devices) {
        return VK_ERROR_OUT_OF_HOST_MEMORY;
    }

    uint32_t cur_device = 0;
    for (cur_idx = 0; cur_idx < group_count; ++cur_idx) {
        for (dev_idx = 0; dev_idx < groups[cur_idx].physicalDeviceCount; ++dev_idx) {
            devices[cur_device++] = groups[cur_idx].physicalDevices[dev_idx];
        }
    }

    // Update the devices based on the loader physical device values.
    res = setup_loader_tramp_phys_devs(inst, phys_dev_count, devices);
    if (VK_SUCCESS != res) {
        return res;
    }

    // Update the devices in the group structures now
    cur_device = 0;
    for (cur_idx = 0; cur_idx < group_count; ++cur_idx) {
        for (dev_idx = 0; dev_idx < groups[cur_idx].physicalDeviceCount; ++dev_idx) {
            groups[cur_idx].physicalDevices[dev_idx] = devices[cur_device++];
        }
    }

    return res;
}

VKAPI_ATTR VkResult VKAPI_CALL terminator_EnumeratePhysicalDevices(VkInstance instance, uint32_t *pPhysicalDeviceCount,
                                                                   VkPhysicalDevice *pPhysicalDevices) {
    struct loader_instance *inst = (struct loader_instance *)instance;
    VkResult res = VK_SUCCESS;

    // Always call the setup loader terminator physical devices because they may
    // have changed at any point.
    res = setup_loader_term_phys_devs(inst);
    if (VK_SUCCESS != res) {
        goto out;
    }

    uint32_t copy_count = inst->phys_dev_count_term;
    if (NULL != pPhysicalDevices) {
        if (copy_count > *pPhysicalDeviceCount) {
            copy_count = *pPhysicalDeviceCount;
            loader_log(inst, VULKAN_LOADER_INFO_BIT, 0,
                       "terminator_EnumeratePhysicalDevices : Trimming device count from %d to %d.", inst->phys_dev_count_term,
                       copy_count);
            res = VK_INCOMPLETE;
        }

        for (uint32_t i = 0; i < copy_count; i++) {
            pPhysicalDevices[i] = (VkPhysicalDevice)inst->phys_devs_term[i];
        }
    }

    *pPhysicalDeviceCount = copy_count;

out:

    return res;
}

VKAPI_ATTR VkResult VKAPI_CALL terminator_EnumerateDeviceExtensionProperties(VkPhysicalDevice physicalDevice,
                                                                             const char *pLayerName, uint32_t *pPropertyCount,
                                                                             VkExtensionProperties *pProperties) {
    struct loader_physical_device_term *phys_dev_term;

    // Any layer or trampoline wrapping should be removed at this point in time can just cast to the expected
    // type for VkPhysicalDevice.
    phys_dev_term = (struct loader_physical_device_term *)physicalDevice;

    // if we got here with a non-empty pLayerName, look up the extensions
    // from the json
    if (pLayerName != NULL && strlen(pLayerName) > 0) {
        uint32_t count;
        uint32_t copy_size;
        const struct loader_instance *inst = phys_dev_term->this_icd_term->this_instance;
        struct loader_device_extension_list *dev_ext_list = NULL;
        struct loader_device_extension_list local_ext_list;
        memset(&local_ext_list, 0, sizeof(local_ext_list));
        if (vk_string_validate(MaxLoaderStringLength, pLayerName) == VK_STRING_ERROR_NONE) {
            for (uint32_t i = 0; i < inst->instance_layer_list.count; i++) {
                struct loader_layer_properties *props = &inst->instance_layer_list.list[i];
                if (strcmp(props->info.layerName, pLayerName) == 0) {
                    dev_ext_list = &props->device_extension_list;
                }
            }

            count = (dev_ext_list == NULL) ? 0 : dev_ext_list->count;
            if (pProperties == NULL) {
                *pPropertyCount = count;
                loader_destroy_generic_list(inst, (struct loader_generic_list *)&local_ext_list);
                return VK_SUCCESS;
            }

            copy_size = *pPropertyCount < count ? *pPropertyCount : count;
            for (uint32_t i = 0; i < copy_size; i++) {
                memcpy(&pProperties[i], &dev_ext_list->list[i].props, sizeof(VkExtensionProperties));
            }
            *pPropertyCount = copy_size;

            loader_destroy_generic_list(inst, (struct loader_generic_list *)&local_ext_list);
            if (copy_size < count) {
                return VK_INCOMPLETE;
            }
        } else {
            loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                       "vkEnumerateDeviceExtensionProperties:  pLayerName is too long or is badly formed");
            return VK_ERROR_EXTENSION_NOT_PRESENT;
        }

        return VK_SUCCESS;
    }

    // This case is during the call down the instance chain with pLayerName == NULL
    struct loader_icd_term *icd_term = phys_dev_term->this_icd_term;
    uint32_t icd_ext_count = *pPropertyCount;
    VkExtensionProperties *icd_props_list = pProperties;
    const struct loader_instance *inst = icd_term->this_instance;
    struct loader_extension_list all_exts = {0};
    VkResult res;

    if (NULL == icd_props_list) {
        // We need to find the count without duplicates. This requires querying the driver for the names of the extensions.
        // A small amount of storage is then needed to facilitate the de-duplication.
        res = icd_term->dispatch.EnumerateDeviceExtensionProperties(phys_dev_term->phys_dev, NULL, &icd_ext_count, NULL);
        if (res != VK_SUCCESS) {
            goto out;
        }
        if (icd_ext_count > 0) {
            icd_props_list = loader_instance_heap_alloc(icd_term->this_instance, sizeof(VkExtensionProperties) * icd_ext_count,
                                                        VK_SYSTEM_ALLOCATION_SCOPE_COMMAND);
            if (NULL == icd_props_list) {
                res = VK_ERROR_OUT_OF_HOST_MEMORY;
                goto out;
            }
        }
    }

    // Get the available device extension count, and if pProperties is not NULL, the extensions as well
    res = icd_term->dispatch.EnumerateDeviceExtensionProperties(phys_dev_term->phys_dev, NULL, &icd_ext_count, icd_props_list);
    if (res != VK_SUCCESS) {
        goto out;
    }

    // Init a list with enough capacity for the device extensions and the implicit layer device extensions
    res = loader_init_generic_list(inst, (struct loader_generic_list *)&all_exts,
                                   sizeof(VkExtensionProperties) * (icd_ext_count + 20));
    if (VK_SUCCESS != res) {
        goto out;
    }

    // Copy over the device extensions into all_exts & deduplicate
    res = loader_add_to_ext_list(inst, &all_exts, icd_ext_count, icd_props_list);
    if (res != VK_SUCCESS) {
        goto out;
    }

    // Iterate over active layers, if they are an implicit layer, add their device extensions
    for (uint32_t i = 0; i < icd_term->this_instance->expanded_activated_layer_list.count; i++) {
        struct loader_layer_properties *layer_props = &icd_term->this_instance->expanded_activated_layer_list.list[i];
        if (0 == (layer_props->type_flags & VK_LAYER_TYPE_FLAG_EXPLICIT_LAYER)) {
            for (uint32_t j = 0; j < layer_props->device_extension_list.count; j++) {
                res = loader_add_to_ext_list(icd_term->this_instance, &all_exts, 1,
                                             &layer_props->device_extension_list.list[j].props);
                if (res != VK_SUCCESS) {
                    goto out;
                }
            }
        }
    }
    uint32_t capacity = *pPropertyCount;
    VkExtensionProperties *props = pProperties;

    res = VK_SUCCESS;
    if (NULL != pProperties) {
        for (uint32_t i = 0; i < all_exts.count && i < capacity; i++) {
            props[i] = all_exts.list[i];
        }

        // Wasn't enough space for the extensions, we did partial copy now return VK_INCOMPLETE
        if (capacity < all_exts.count) {
            res = VK_INCOMPLETE;
        } else {
            *pPropertyCount = all_exts.count;
        }
    } else {
        *pPropertyCount = all_exts.count;
    }

out:

    loader_destroy_generic_list(icd_term->this_instance, (struct loader_generic_list *)&all_exts);
    if (NULL == pProperties && NULL != icd_props_list) {
        loader_instance_heap_free(icd_term->this_instance, icd_props_list);
    }
    return res;
}

VkStringErrorFlags vk_string_validate(const int max_length, const char *utf8) {
    VkStringErrorFlags result = VK_STRING_ERROR_NONE;
    int num_char_bytes = 0;
    int i, j;

    if (utf8 == NULL) {
        return VK_STRING_ERROR_NULL_PTR;
    }

    for (i = 0; i <= max_length; i++) {
        if (utf8[i] == 0) {
            break;
        } else if (i == max_length) {
            result |= VK_STRING_ERROR_LENGTH;
            break;
        } else if ((utf8[i] >= 0x20) && (utf8[i] < 0x7f)) {
            num_char_bytes = 0;
        } else if ((utf8[i] & UTF8_ONE_BYTE_MASK) == UTF8_ONE_BYTE_CODE) {
            num_char_bytes = 1;
        } else if ((utf8[i] & UTF8_TWO_BYTE_MASK) == UTF8_TWO_BYTE_CODE) {
            num_char_bytes = 2;
        } else if ((utf8[i] & UTF8_THREE_BYTE_MASK) == UTF8_THREE_BYTE_CODE) {
            num_char_bytes = 3;
        } else {
            result = VK_STRING_ERROR_BAD_DATA;
        }

        // Validate the following num_char_bytes of data
        for (j = 0; (j < num_char_bytes) && (i < max_length); j++) {
            if (++i == max_length) {
                result |= VK_STRING_ERROR_LENGTH;
                break;
            }
            if ((utf8[i] & UTF8_DATA_BYTE_MASK) != UTF8_DATA_BYTE_CODE) {
                result |= VK_STRING_ERROR_BAD_DATA;
            }
        }
    }
    return result;
}

VKAPI_ATTR VkResult VKAPI_CALL terminator_EnumerateInstanceVersion(const VkEnumerateInstanceVersionChain *chain,
                                                                   uint32_t *pApiVersion) {
    // NOTE: The Vulkan WG doesn't want us checking pApiVersion for NULL, but instead
    // prefers us crashing.
    *pApiVersion = VK_HEADER_VERSION_COMPLETE;
    return VK_SUCCESS;
}

VKAPI_ATTR VkResult VKAPI_CALL
terminator_EnumerateInstanceExtensionProperties(const VkEnumerateInstanceExtensionPropertiesChain *chain, const char *pLayerName,
                                                uint32_t *pPropertyCount, VkExtensionProperties *pProperties) {
    struct loader_extension_list *global_ext_list = NULL;
    struct loader_layer_list instance_layers;
    struct loader_extension_list local_ext_list;
    struct loader_icd_tramp_list icd_tramp_list;
    uint32_t copy_size;
    VkResult res = VK_SUCCESS;

    memset(&local_ext_list, 0, sizeof(local_ext_list));
    memset(&instance_layers, 0, sizeof(instance_layers));
    memset(&icd_tramp_list, 0, sizeof(icd_tramp_list));

    // Get layer libraries if needed
    if (pLayerName && strlen(pLayerName) != 0) {
        if (vk_string_validate(MaxLoaderStringLength, pLayerName) != VK_STRING_ERROR_NONE) {
            assert(VK_FALSE && "vkEnumerateInstanceExtensionProperties: pLayerName is too long or is badly formed");
            res = VK_ERROR_EXTENSION_NOT_PRESENT;
            goto out;
        }

        res = loader_scan_for_layers(NULL, &instance_layers);
        if (VK_SUCCESS != res) {
            goto out;
        }
        for (uint32_t i = 0; i < instance_layers.count; i++) {
            struct loader_layer_properties *props = &instance_layers.list[i];
            if (strcmp(props->info.layerName, pLayerName) == 0) {
                global_ext_list = &props->instance_extension_list;
                break;
            }
        }
    } else {
        // Preload ICD libraries so subsequent calls to EnumerateInstanceExtensionProperties don't have to load them
        loader_preload_icds();

        // Scan/discover all ICD libraries
        res = loader_icd_scan(NULL, &icd_tramp_list, NULL, NULL);
        // EnumerateInstanceExtensionProperties can't return anything other than OOM or VK_ERROR_LAYER_NOT_PRESENT
        if ((VK_SUCCESS != res && icd_tramp_list.count > 0) || res == VK_ERROR_OUT_OF_HOST_MEMORY) {
            goto out;
        }
        // Get extensions from all ICD's, merge so no duplicates
        res = loader_get_icd_loader_instance_extensions(NULL, &icd_tramp_list, &local_ext_list);
        if (VK_SUCCESS != res) {
            goto out;
        }
        loader_scanned_icd_clear(NULL, &icd_tramp_list);

        // Append enabled implicit layers.
        res = loader_scan_for_implicit_layers(NULL, &instance_layers, NULL);
        if (VK_SUCCESS != res) {
            goto out;
        }
        for (uint32_t i = 0; i < instance_layers.count; i++) {
            struct loader_extension_list *ext_list = &instance_layers.list[i].instance_extension_list;
            loader_add_to_ext_list(NULL, &local_ext_list, ext_list->count, ext_list->list);
        }

        global_ext_list = &local_ext_list;
    }

    if (global_ext_list == NULL) {
        res = VK_ERROR_LAYER_NOT_PRESENT;
        goto out;
    }

    if (pProperties == NULL) {
        *pPropertyCount = global_ext_list->count;
        goto out;
    }

    copy_size = *pPropertyCount < global_ext_list->count ? *pPropertyCount : global_ext_list->count;
    for (uint32_t i = 0; i < copy_size; i++) {
        memcpy(&pProperties[i], &global_ext_list->list[i], sizeof(VkExtensionProperties));
    }
    *pPropertyCount = copy_size;

    if (copy_size < global_ext_list->count) {
        res = VK_INCOMPLETE;
        goto out;
    }

out:
    loader_destroy_generic_list(NULL, (struct loader_generic_list *)&icd_tramp_list);
    loader_destroy_generic_list(NULL, (struct loader_generic_list *)&local_ext_list);
    loader_delete_layer_list_and_properties(NULL, &instance_layers);
    return res;
}

VKAPI_ATTR VkResult VKAPI_CALL terminator_EnumerateInstanceLayerProperties(const VkEnumerateInstanceLayerPropertiesChain *chain,
                                                                           uint32_t *pPropertyCount,
                                                                           VkLayerProperties *pProperties) {
    VkResult result = VK_SUCCESS;
    struct loader_layer_list instance_layer_list;

    LOADER_PLATFORM_THREAD_ONCE(&once_init, loader_initialize);

    uint32_t copy_size;

    // Get layer libraries
    memset(&instance_layer_list, 0, sizeof(instance_layer_list));
    result = loader_scan_for_layers(NULL, &instance_layer_list);
    if (VK_SUCCESS != result) {
        goto out;
    }

    if (pProperties == NULL) {
        *pPropertyCount = instance_layer_list.count;
        goto out;
    }

    copy_size = (*pPropertyCount < instance_layer_list.count) ? *pPropertyCount : instance_layer_list.count;
    for (uint32_t i = 0; i < copy_size; i++) {
        memcpy(&pProperties[i], &instance_layer_list.list[i].info, sizeof(VkLayerProperties));
    }

    *pPropertyCount = copy_size;

    if (copy_size < instance_layer_list.count) {
        result = VK_INCOMPLETE;
        goto out;
    }

out:

    loader_delete_layer_list_and_properties(NULL, &instance_layer_list);
    return result;
}

// ---- Vulkan Core 1.1 terminators

VKAPI_ATTR VkResult VKAPI_CALL terminator_EnumeratePhysicalDeviceGroups(
    VkInstance instance, uint32_t *pPhysicalDeviceGroupCount, VkPhysicalDeviceGroupProperties *pPhysicalDeviceGroupProperties) {
    struct loader_instance *inst = (struct loader_instance *)instance;

    VkResult res = VK_SUCCESS;
    struct loader_icd_term *icd_term;
    uint32_t total_count = 0;
    uint32_t cur_icd_group_count = 0;
    VkPhysicalDeviceGroupPropertiesKHR **new_phys_dev_groups = NULL;
    struct loader_physical_device_group_term *local_phys_dev_groups = NULL;
    PFN_vkEnumeratePhysicalDeviceGroups fpEnumeratePhysicalDeviceGroups = NULL;
    struct loader_phys_dev_per_icd *sorted_phys_dev_array = NULL;
    uint32_t sorted_count = 0;

    // For each ICD, query the number of physical device groups, and then get an
    // internal value for those physical devices.
    icd_term = inst->icd_terms;
    for (uint32_t icd_idx = 0; NULL != icd_term; icd_term = icd_term->next, icd_idx++) {
        // Get the function pointer to use to call into the ICD. This could be the core or KHR version
        if (inst->enabled_known_extensions.khr_device_group_creation) {
            fpEnumeratePhysicalDeviceGroups = icd_term->dispatch.EnumeratePhysicalDeviceGroupsKHR;
        } else {
            fpEnumeratePhysicalDeviceGroups = icd_term->dispatch.EnumeratePhysicalDeviceGroups;
        }

        cur_icd_group_count = 0;
        if (NULL == fpEnumeratePhysicalDeviceGroups) {
            // Treat each ICD's GPU as it's own group if the extension isn't supported
            res = icd_term->dispatch.EnumeratePhysicalDevices(icd_term->instance, &cur_icd_group_count, NULL);
            if (res != VK_SUCCESS) {
                loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                           "terminator_EnumeratePhysicalDeviceGroups:  Failed during dispatch call of \'EnumeratePhysicalDevices\' "
                           "to ICD %d to get plain phys dev count.",
                           icd_idx);
                continue;
            }
        } else {
            // Query the actual group info
            res = fpEnumeratePhysicalDeviceGroups(icd_term->instance, &cur_icd_group_count, NULL);
            if (res != VK_SUCCESS) {
                loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                           "terminator_EnumeratePhysicalDeviceGroups:  Failed during dispatch call of "
                           "\'EnumeratePhysicalDeviceGroups\' to ICD %d to get count.",
                           icd_idx);
                continue;
            }
        }
        total_count += cur_icd_group_count;
    }

    // If GPUs not sorted yet, look through them and generate list of all available GPUs
    if (0 == total_count || 0 == inst->total_gpu_count) {
        res = setup_loader_term_phys_devs(inst);
        if (VK_SUCCESS != res) {
            goto out;
        }
    }

    if (NULL != pPhysicalDeviceGroupProperties) {
        // Create an array for the new physical device groups, which will be stored
        // in the instance for the Terminator code.
        new_phys_dev_groups = (VkPhysicalDeviceGroupProperties **)loader_instance_heap_calloc(
            inst, total_count * sizeof(VkPhysicalDeviceGroupProperties *), VK_SYSTEM_ALLOCATION_SCOPE_INSTANCE);
        if (NULL == new_phys_dev_groups) {
            loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                       "terminator_EnumeratePhysicalDeviceGroups:  Failed to allocate new physical device group array of size %d",
                       total_count);
            res = VK_ERROR_OUT_OF_HOST_MEMORY;
            goto out;
        }

        // Create a temporary array (on the stack) to keep track of the
        // returned VkPhysicalDevice values.
        local_phys_dev_groups = loader_stack_alloc(sizeof(struct loader_physical_device_group_term) * total_count);
        // Initialize the memory to something valid
        memset(local_phys_dev_groups, 0, sizeof(struct loader_physical_device_group_term) * total_count);

#if defined(_WIN32)
        // Get the physical devices supported by platform sorting mechanism into a separate list
        res = windows_read_sorted_physical_devices(inst, &sorted_count, &sorted_phys_dev_array);
        if (VK_SUCCESS != res) {
            goto out;
        }
#endif

        cur_icd_group_count = 0;
        icd_term = inst->icd_terms;
        for (uint8_t icd_idx = 0; NULL != icd_term; icd_term = icd_term->next, icd_idx++) {
            uint32_t count_this_time = total_count - cur_icd_group_count;

            // Get the function pointer to use to call into the ICD. This could be the core or KHR version
            if (inst->enabled_known_extensions.khr_device_group_creation) {
                fpEnumeratePhysicalDeviceGroups = icd_term->dispatch.EnumeratePhysicalDeviceGroupsKHR;
            } else {
                fpEnumeratePhysicalDeviceGroups = icd_term->dispatch.EnumeratePhysicalDeviceGroups;
            }

            if (NULL == fpEnumeratePhysicalDeviceGroups) {
                icd_term->dispatch.EnumeratePhysicalDevices(icd_term->instance, &count_this_time, NULL);

                VkPhysicalDevice *phys_dev_array = loader_stack_alloc(sizeof(VkPhysicalDevice) * count_this_time);
                if (NULL == phys_dev_array) {
                    loader_log(
                        inst, VULKAN_LOADER_ERROR_BIT, 0,
                        "terminator_EnumeratePhysicalDeviceGroups:  Failed to allocate local physical device array of size %d",
                        count_this_time);
                    res = VK_ERROR_OUT_OF_HOST_MEMORY;
                    goto out;
                }

                res = icd_term->dispatch.EnumeratePhysicalDevices(icd_term->instance, &count_this_time, phys_dev_array);
                if (res != VK_SUCCESS) {
                    loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                               "terminator_EnumeratePhysicalDeviceGroups:  Failed during dispatch call of "
                               "\'EnumeratePhysicalDevices\' to ICD %d to get plain phys dev count.",
                               icd_idx);
                    goto out;
                }

                // Add each GPU as it's own group
                for (uint32_t indiv_gpu = 0; indiv_gpu < count_this_time; indiv_gpu++) {
                    uint32_t cur_index = indiv_gpu + cur_icd_group_count;
                    local_phys_dev_groups[cur_index].this_icd_term = icd_term;
                    local_phys_dev_groups[cur_index].icd_index = icd_idx;
                    local_phys_dev_groups[cur_index].group_props.physicalDeviceCount = 1;
                    local_phys_dev_groups[cur_index].group_props.physicalDevices[0] = phys_dev_array[indiv_gpu];
                }

            } else {
                res = fpEnumeratePhysicalDeviceGroups(icd_term->instance, &count_this_time, NULL);
                if (res != VK_SUCCESS) {
                    loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                               "terminator_EnumeratePhysicalDeviceGroups:  Failed during dispatch call of "
                               "\'EnumeratePhysicalDeviceGroups\' to ICD %d to get group count.",
                               icd_idx);
                    goto out;
                }
                if (cur_icd_group_count + count_this_time < *pPhysicalDeviceGroupCount) {
                    // The total amount is still less than the amount of physical device group data passed in
                    // by the callee.  Therefore, we don't have to allocate any temporary structures and we
                    // can just use the data that was passed in.
                    res = fpEnumeratePhysicalDeviceGroups(icd_term->instance, &count_this_time,
                                                          &pPhysicalDeviceGroupProperties[cur_icd_group_count]);
                    if (res != VK_SUCCESS) {
                        loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                                   "terminator_EnumeratePhysicalDeviceGroups:  Failed during dispatch call of "
                                   "\'EnumeratePhysicalDeviceGroups\' to ICD %d to get group information.",
                                   icd_idx);
                        goto out;
                    }
                    for (uint32_t group = 0; group < count_this_time; ++group) {
                        uint32_t cur_index = group + cur_icd_group_count;
                        local_phys_dev_groups[cur_index].group_props = pPhysicalDeviceGroupProperties[cur_index];
                        local_phys_dev_groups[cur_index].this_icd_term = icd_term;
                        local_phys_dev_groups[cur_index].icd_index = icd_idx;
                    }
                } else {
                    // There's not enough space in the callee's allocated pPhysicalDeviceGroupProperties structs,
                    // so we have to allocate temporary versions to collect all the data.  However, we need to make
                    // sure that at least the ones we do query utilize any pNext data in the callee's version.
                    VkPhysicalDeviceGroupProperties *tmp_group_props =
                        loader_stack_alloc(count_this_time * sizeof(VkPhysicalDeviceGroupProperties));
                    for (uint32_t group = 0; group < count_this_time; group++) {
                        tmp_group_props[group].sType = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_GROUP_PROPERTIES_KHR;
                        uint32_t cur_index = group + cur_icd_group_count;
                        if (*pPhysicalDeviceGroupCount > cur_index) {
                            tmp_group_props[group].pNext = pPhysicalDeviceGroupProperties[cur_index].pNext;
                        } else {
                            tmp_group_props[group].pNext = NULL;
                        }
                        tmp_group_props[group].subsetAllocation = false;
                    }

                    res = fpEnumeratePhysicalDeviceGroups(icd_term->instance, &count_this_time, tmp_group_props);
                    if (res != VK_SUCCESS) {
                        loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                                   "terminator_EnumeratePhysicalDeviceGroups:  Failed during dispatch call of "
                                   "\'EnumeratePhysicalDeviceGroups\' to ICD %d  to get group information for temp data.",
                                   icd_idx);
                        goto out;
                    }
                    for (uint32_t group = 0; group < count_this_time; ++group) {
                        uint32_t cur_index = group + cur_icd_group_count;
                        local_phys_dev_groups[cur_index].group_props = tmp_group_props[group];
                        local_phys_dev_groups[cur_index].this_icd_term = icd_term;
                        local_phys_dev_groups[cur_index].icd_index = icd_idx;
                    }
                }
                if (VK_SUCCESS != res) {
                    loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                               "terminator_EnumeratePhysicalDeviceGroups:  Failed during dispatch call of "
                               "\'EnumeratePhysicalDeviceGroups\' to ICD %d to get content.",
                               icd_idx);
                    goto out;
                }
            }

            cur_icd_group_count += count_this_time;
        }

#ifdef LOADER_ENABLE_LINUX_SORT
        if (is_linux_sort_enabled(inst)) {
            // Get the physical devices supported by platform sorting mechanism into a separate list
            res = linux_sort_physical_device_groups(inst, total_count, local_phys_dev_groups);
        }
#elif defined(_WIN32)
        // The Windows sorting information is only on physical devices.  We need to take that and convert it to the group
        // information if it's present.
        if (sorted_count > 0) {
            res =
                windows_sort_physical_device_groups(inst, total_count, local_phys_dev_groups, sorted_count, sorted_phys_dev_array);
        }
#endif  // LOADER_ENABLE_LINUX_SORT

        // Just to be safe, make sure we successfully completed setup_loader_term_phys_devs above
        // before attempting to do the following.  By verifying that setup_loader_term_phys_devs ran
        // first, it guarantees that each physical device will have a loader-specific handle.
        if (NULL != inst->phys_devs_term) {
            for (uint32_t group = 0; group < total_count; group++) {
                for (uint32_t group_gpu = 0; group_gpu < local_phys_dev_groups[group].group_props.physicalDeviceCount;
                     group_gpu++) {
                    bool found = false;
                    for (uint32_t term_gpu = 0; term_gpu < inst->phys_dev_count_term; term_gpu++) {
                        if (local_phys_dev_groups[group].group_props.physicalDevices[group_gpu] ==
                            inst->phys_devs_term[term_gpu]->phys_dev) {
                            local_phys_dev_groups[group].group_props.physicalDevices[group_gpu] =
                                (VkPhysicalDevice)inst->phys_devs_term[term_gpu];
                            found = true;
                            break;
                        }
                    }
                    if (!found) {
                        loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                                   "terminator_EnumeratePhysicalDeviceGroups:  Failed to find GPU %d in group %d returned by "
                                   "\'EnumeratePhysicalDeviceGroups\' in list returned by \'EnumeratePhysicalDevices\'",
                                   group_gpu, group);
                        res = VK_ERROR_INITIALIZATION_FAILED;
                        goto out;
                    }
                }
            }
        }

        uint32_t idx = 0;

        // Copy or create everything to fill the new array of physical device groups
        for (uint32_t group = 0; group < total_count; group++) {
            // Skip groups which have been included through sorting
            if (local_phys_dev_groups[group].group_props.physicalDeviceCount == 0) {
                continue;
            }

            // Find the VkPhysicalDeviceGroupProperties object in local_phys_dev_groups
            VkPhysicalDeviceGroupProperties *group_properties = &local_phys_dev_groups[group].group_props;

            // Check if this physical device group with the same contents is already in the old buffer
            for (uint32_t old_idx = 0; old_idx < inst->phys_dev_group_count_term; old_idx++) {
                if (NULL != group_properties && NULL != inst->phys_dev_groups_term[old_idx] &&
                    group_properties->physicalDeviceCount == inst->phys_dev_groups_term[old_idx]->physicalDeviceCount) {
                    bool found_all_gpus = true;
                    for (uint32_t old_gpu = 0; old_gpu < inst->phys_dev_groups_term[old_idx]->physicalDeviceCount; old_gpu++) {
                        bool found_gpu = false;
                        for (uint32_t new_gpu = 0; new_gpu < group_properties->physicalDeviceCount; new_gpu++) {
                            if (group_properties->physicalDevices[new_gpu] ==
                                inst->phys_dev_groups_term[old_idx]->physicalDevices[old_gpu]) {
                                found_gpu = true;
                                break;
                            }
                        }

                        if (!found_gpu) {
                            found_all_gpus = false;
                            break;
                        }
                    }
                    if (!found_all_gpus) {
                        continue;
                    } else {
                        new_phys_dev_groups[idx] = inst->phys_dev_groups_term[old_idx];
                        break;
                    }
                }
            }
            // If this physical device group isn't in the old buffer, create it
            if (group_properties != NULL && NULL == new_phys_dev_groups[idx]) {
                new_phys_dev_groups[idx] = (VkPhysicalDeviceGroupPropertiesKHR *)loader_instance_heap_alloc(
                    inst, sizeof(VkPhysicalDeviceGroupPropertiesKHR), VK_SYSTEM_ALLOCATION_SCOPE_INSTANCE);
                if (NULL == new_phys_dev_groups[idx]) {
                    loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0,
                               "terminator_EnumeratePhysicalDeviceGroups:  Failed to allocate physical device group Terminator "
                               "object %d",
                               idx);
                    total_count = idx;
                    res = VK_ERROR_OUT_OF_HOST_MEMORY;
                    goto out;
                }
                memcpy(new_phys_dev_groups[idx], group_properties, sizeof(VkPhysicalDeviceGroupPropertiesKHR));
            }

            ++idx;
        }
    }

out:

    if (NULL != pPhysicalDeviceGroupProperties) {
        if (VK_SUCCESS != res) {
            if (NULL != new_phys_dev_groups) {
                // We've encountered an error, so we should free the new buffers.
                for (uint32_t i = 0; i < total_count; i++) {
                    // If an OOM occurred inside the copying of the new physical device groups into the existing array will
                    // leave some of the old physical device groups in the array which may have been copied into the new array,
                    // leading to them being freed twice. To avoid this we just make sure to not delete physical device groups
                    // which were copied.
                    bool found = false;
                    if (NULL != inst->phys_devs_term) {
                        for (uint32_t old_idx = 0; old_idx < inst->phys_dev_group_count_term; old_idx++) {
                            if (new_phys_dev_groups[i] == inst->phys_dev_groups_term[old_idx]) {
                                found = true;
                                break;
                            }
                        }
                    }
                    if (!found) {
                        loader_instance_heap_free(inst, new_phys_dev_groups[i]);
                    }
                }
                loader_instance_heap_free(inst, new_phys_dev_groups);
            }
        } else {
            if (NULL != inst->phys_dev_groups_term) {
                // Free everything in the old array that was not copied into the new array
                // here.  We can't attempt to do that before here since the previous loop
                // looking before the "out:" label may hit an out of memory condition resulting
                // in memory leaking.
                for (uint32_t i = 0; i < inst->phys_dev_group_count_term; i++) {
                    bool found = false;
                    for (uint32_t j = 0; j < total_count; j++) {
                        if (inst->phys_dev_groups_term[i] == new_phys_dev_groups[j]) {
                            found = true;
                            break;
                        }
                    }
                    if (!found) {
                        loader_instance_heap_free(inst, inst->phys_dev_groups_term[i]);
                    }
                }
                loader_instance_heap_free(inst, inst->phys_dev_groups_term);
            }

            // Swap in the new physical device group list
            inst->phys_dev_group_count_term = total_count;
            inst->phys_dev_groups_term = new_phys_dev_groups;
        }

        if (sorted_phys_dev_array != NULL) {
            for (uint32_t i = 0; i < sorted_count; ++i) {
                if (sorted_phys_dev_array[i].device_count > 0 && sorted_phys_dev_array[i].physical_devices != NULL) {
                    loader_instance_heap_free(inst, sorted_phys_dev_array[i].physical_devices);
                }
            }
            loader_instance_heap_free(inst, sorted_phys_dev_array);
        }

        uint32_t copy_count = inst->phys_dev_group_count_term;
        if (NULL != pPhysicalDeviceGroupProperties) {
            if (copy_count > *pPhysicalDeviceGroupCount) {
                copy_count = *pPhysicalDeviceGroupCount;
                loader_log(inst, VULKAN_LOADER_INFO_BIT, 0,
                           "terminator_EnumeratePhysicalDeviceGroups : Trimming device count from %d to %d.",
                           inst->phys_dev_group_count_term, copy_count);
                res = VK_INCOMPLETE;
            }

            for (uint32_t i = 0; i < copy_count; i++) {
                memcpy(&pPhysicalDeviceGroupProperties[i], inst->phys_dev_groups_term[i], sizeof(VkPhysicalDeviceGroupProperties));
            }
        }

        *pPhysicalDeviceGroupCount = copy_count;

    } else {
        *pPhysicalDeviceGroupCount = total_count;
    }
    return res;
}