loader: Log VkInstanceCreateInfo for debugging

vkCreateInstance now logs the application's VkApplicationInfo (app and engine
name and version, apiVersion) plus the requested instance layers and
extensions at info level, so they show up under VK_LOADER_DEBUG. This helps
when debugging instance setup and when matching driver workarounds to a
specific application.

Closes #1819

Author: BoiledElectricity

loader/trampoline.c

@@ -478,6 +478,41 @@ void loader_remove_instance_only_debug_funcs(struct loader_instance *ptr_instanc
     }
 }
 
+// Dump the app's VkInstanceCreateInfo under VK_LOADER_DEBUG (names, versions, requested layers/extensions). Handy
+// for debugging instance setup and matching driver workarounds to a specific app.
+static void loader_log_instance_create_info(const struct loader_instance *inst, const VkInstanceCreateInfo *pCreateInfo) {
+    const VkApplicationInfo *app_info = pCreateInfo->pApplicationInfo;
+    const char *app_name = (app_info && app_info->pApplicationName) ? app_info->pApplicationName : "";
+    const char *engine_name = (app_info && app_info->pEngineName) ? app_info->pEngineName : "";
+    uint32_t app_version = app_info ? app_info->applicationVersion : 0;
+    uint32_t engine_version = app_info ? app_info->engineVersion : 0;
+    uint32_t api_version = app_info ? app_info->apiVersion : 0;
+
+    loader_log(inst, VULKAN_LOADER_INFO_BIT, 0,
+               "vkCreateInstance: applicationName: \"%s\", applicationVersion: %u, engineName: \"%s\", engineVersion: %u, "
+               "apiVersion: %u.%u.%u",
+               app_name, app_version, engine_name, engine_version, VK_API_VERSION_MAJOR(api_version),
+               VK_API_VERSION_MINOR(api_version), VK_API_VERSION_PATCH(api_version));
+
+    // Guard the name arrays: this runs before the loader validates pCreateInfo, so the count may be non-zero with a null
+    // array (see the null-pointer tests).
+    loader_log(inst, VULKAN_LOADER_INFO_BIT, 0,
+               "vkCreateInstance: Requested %u instance layer(s):", pCreateInfo->enabledLayerCount);
+    if (pCreateInfo->ppEnabledLayerNames) {
+        for (uint32_t i = 0; i < pCreateInfo->enabledLayerCount; ++i) {
+            loader_log(inst, VULKAN_LOADER_INFO_BIT, 0, "   %s", pCreateInfo->ppEnabledLayerNames[i]);
+        }
+    }
+
+    loader_log(inst, VULKAN_LOADER_INFO_BIT, 0,
+               "vkCreateInstance: Requested %u instance extension(s):", pCreateInfo->enabledExtensionCount);
+    if (pCreateInfo->ppEnabledExtensionNames) {
+        for (uint32_t i = 0; i < pCreateInfo->enabledExtensionCount; ++i) {
+            loader_log(inst, VULKAN_LOADER_INFO_BIT, 0, "   %s", pCreateInfo->ppEnabledExtensionNames[i]);
+        }
+    }
+}
+
 LOADER_EXPORT VKAPI_ATTR VkResult VKAPI_CALL vkCreateInstance(const VkInstanceCreateInfo *pCreateInfo,
                                                               const VkAllocationCallbacks *pAllocator, VkInstance *pInstance) {
     struct loader_instance *ptr_instance = NULL;
@@ -543,6 +578,8 @@ LOADER_EXPORT VKAPI_ATTR VkResult VKAPI_CALL vkCreateInstance(const VkInstanceCr
         goto out;
     }
 
+    loader_log_instance_create_info(ptr_instance, pCreateInfo);
+
     VkResult settings_file_res = get_loader_settings(ptr_instance, &ptr_instance->settings);
     if (settings_file_res == VK_ERROR_OUT_OF_HOST_MEMORY) {
         res = settings_file_res;

tests/loader_regression_tests.cpp

@@ -142,6 +142,27 @@ TEST(CreateInstance, ApiVersionBelow1_0) {
                        "greater than or equal to the value of VK_API_VERSION_1_0 [VUID-VkApplicationInfo-apiVersion]"));
 }
 
+// The loader should log the application's VkInstanceCreateInfo so it shows up under VK_LOADER_DEBUG. See #1819.
+TEST(CreateInstance, LogsInstanceCreateInfo) {
+    FrameworkEnvironment env{};
+    env.add_icd(TEST_ICD_PATH_VERSION_2);
+
+    DebugUtilsLogger debug_log{VK_DEBUG_UTILS_MESSAGE_SEVERITY_INFO_BIT_EXT};
+    InstWrapper inst{env.vulkan_functions};
+    inst.create_info.set_app_name("MyTestApp")
+        .set_app_version(42)
+        .set_engine_name("MyTestEngine")
+        .set_engine_version(7)
+        .set_api_version(1, 2, 0);
+    FillDebugUtilsCreateDetails(inst.create_info, debug_log);
+    inst.CheckCreate();
+
+    ASSERT_TRUE(debug_log.find("applicationName: \"MyTestApp\", applicationVersion: 42"));
+    ASSERT_TRUE(debug_log.find("engineName: \"MyTestEngine\", engineVersion: 7, apiVersion: 1.2.0"));
+    // FillDebugUtilsCreateDetails enables VK_EXT_debug_utils, so it should appear in the requested-extensions dump.
+    ASSERT_TRUE(debug_log.find("VK_EXT_debug_utils"));
+}
+
 TEST(CreateInstance, ConsecutiveCreate) {
     FrameworkEnvironment env{};
     env.add_icd(TEST_ICD_PATH_VERSION_2);