[ET-VK][mac] Allow vulkan binaries to work with Vulkan SDK + fixes to…

… enable debugPrintf extension

## Context

Add a buck config option to prevent linking against MoltenVK when building for MacOS, instead opting to use volk. This is useful for seeing debug print statments from GLSL code.

Also implement some fixes to make things work when using system-installed Vulkan SDK, and some fixes to enable using debug Printf extension on Mac.

Specifically, the fixes are as follows:

* On newer versions of the Vulkan SDK, a portability instance extension needs to be explicitly enabled, otherwise creating the Vulkan instance will complain about the driver being incompatible. [source](https://stackoverflow.com/questions/58732459/vk-error-incompatible-driver-with-mac-os-and-vulkan-moltenvk)
* VkConfig on Mac doesn't show options to enable debugprintf, therefore it has to be enabled programmatically.

Differential Revision: [D68650936](https://our.internmc.facebook.com/intern/diff/D68650936/)

ghstack-source-id: 263006772
Pull Request resolved: #7957

Co-authored-by: Stephen Jia <[email protected]>

backends/vulkan/runtime/vk_api/Runtime.cpp

@@ -92,28 +92,52 @@ VkInstance create_instance(const RuntimeConfig& config) {
   std::vector<const char*> enabled_layers;
   std::vector<const char*> enabled_extensions;
 
+  std::vector<const char*> requested_layers;
+  std::vector<const char*> requested_extensions;
+
   if (config.enable_validation_messages) {
-    std::vector<const char*> requested_layers{
-        // "VK_LAYER_LUNARG_api_dump",
-        "VK_LAYER_KHRONOS_validation",
-    };
-    std::vector<const char*> requested_extensions{
+    requested_layers.emplace_back("VK_LAYER_KHRONOS_validation");
 #ifdef VK_EXT_debug_report
-        VK_EXT_DEBUG_REPORT_EXTENSION_NAME,
+    requested_extensions.emplace_back(VK_EXT_DEBUG_REPORT_EXTENSION_NAME);
 #endif /* VK_EXT_debug_report */
-    };
-
-    find_requested_layers_and_extensions(
-        enabled_layers,
-        enabled_extensions,
-        requested_layers,
-        requested_extensions);
   }
 
+  VkInstanceCreateFlags instance_flags = 0;
+#ifdef __APPLE__
+  instance_flags |= VK_INSTANCE_CREATE_ENUMERATE_PORTABILITY_BIT_KHR;
+  requested_extensions.emplace_back(
+      VK_KHR_PORTABILITY_ENUMERATION_EXTENSION_NAME);
+#endif
+
+  find_requested_layers_and_extensions(
+      enabled_layers,
+      enabled_extensions,
+      requested_layers,
+      requested_extensions);
+
+  const void* instance_create_next = nullptr;
+  // VkConfig on Mac platforms does not expose debugPrintf settings for whatever
+  // reason so it has to be enabled manually.
+#if defined(__APPLE__) && defined(VULKAN_DEBUG)
+  std::vector<VkValidationFeatureEnableEXT> enabled_validation_features{
+      VK_VALIDATION_FEATURE_ENABLE_DEBUG_PRINTF_EXT,
+  };
+  VkValidationFeaturesEXT validation_features = {
+      VK_STRUCTURE_TYPE_VALIDATION_FEATURES_EXT, // sType
+      nullptr, // pNext
+      static_cast<uint32_t>(
+          enabled_validation_features.size()), // enabledValidationFeatureCount
+      enabled_validation_features.data(), // pEnabledValidationFeatures
+      0,
+      nullptr, // pDisabledValidationFeatures
+  };
+  instance_create_next = &validation_features;
+#endif /* __APPLE__ && VULKAN_DEBUG */
+
   const VkInstanceCreateInfo instance_create_info{
       VK_STRUCTURE_TYPE_INSTANCE_CREATE_INFO, // sType
-      nullptr, // pNext
-      0u, // flags
+      instance_create_next, // pNext
+      instance_flags, // flags
       &application_info, // pApplicationInfo
       static_cast<uint32_t>(enabled_layers.size()), // enabledLayerCount
       enabled_layers.data(), // ppEnabledLayerNames

backends/vulkan/targets.bzl

@@ -142,19 +142,31 @@ def define_common_targets(is_fbcode = False):
                 "fbsource//third-party/swiftshader/lib/linux-x64:libvk_swiftshader_so",
             ]
         else:
+            link_moltenvk = read_config("etvk", "link_moltenvk", "1") == "1"
+            mac_deps = default_deps
+            if link_moltenvk:
+                mac_deps = [
+                    "//third-party/khronos:moltenVK_static"
+                ]
+            mac_flags = default_flags
+            if link_moltenvk:
+                mac_flags = []
+
             VK_API_DEPS += select({
                 "DEFAULT": default_deps,
                 "ovr_config//os:android": android_deps,
-                "ovr_config//os:macos": [
-                    "//third-party/khronos:moltenVK_static"
-                ],
+                "ovr_config//os:macos": mac_deps,
             })
             VK_API_PREPROCESSOR_FLAGS += select({
                 "DEFAULT": default_flags,
                 "ovr_config//os:android": android_flags,
-                "ovr_config//os:macos": []
+                "ovr_config//os:macos": mac_flags,
             })
 
+            debug_mode = read_config("etvk", "debug", "0") == "1"
+            if debug_mode:
+                VK_API_PREPROCESSOR_FLAGS += ["-DVULKAN_DEBUG"]
+
         runtime.cxx_library(
             name = "vulkan_compute_api{}".format(suffix),
             compiler_flags = get_vulkan_compiler_flags(),