Support the VK_EXT_memory_budget extension.

This requires macOS 10.13 or iOS 11, for the `currentAllocatedSize`
property of `MTLDevice`. Ideally, we'd check for that method instead of
keying on the version.

Docs/MoltenVK_Runtime_UserGuide.md

@@ -243,6 +243,7 @@ In addition to the core *Vulkan* API, **MoltenVK**  also supports the following
 - `VK_KHR_swapchain`
 - `VK_KHR_swapchain_mutable_format`
 - `VK_KHR_variable_pointers`
+- `VK_EXT_memory_budget`
 - `VK_EXT_shader_viewport_index_layer`
 - `VK_EXT_vertex_attribute_divisor`
 - `VK_EXTX_portability_subset`

MoltenVK/MoltenVK/GPUObjects/MVKDevice.h

@@ -210,7 +210,7 @@ public:
 	VkResult getPhysicalDeviceMemoryProperties(VkPhysicalDeviceMemoryProperties* pMemoryProperties);
 
 	/** Populates the specified memory properties with the memory characteristics of this device. */
-	VkResult getPhysicalDeviceMemoryProperties(VkPhysicalDeviceMemoryProperties2KHR* pMemoryProperties);
+	VkResult getPhysicalDeviceMemoryProperties(VkPhysicalDeviceMemoryProperties2* pMemoryProperties);
 
 	/**
 	 * Returns a bit mask of all memory type indices. 

MoltenVK/MoltenVK/GPUObjects/MVKDevice.mm

@@ -165,7 +165,7 @@ void MVKPhysicalDevice::getProperties(VkPhysicalDeviceProperties2* properties) {
 				break;
 			}
             default:
-                next = (MVKVkAPIStructHeader*)((VkPhysicalDeviceProperties2*)next)->pNext;
+                next = (MVKVkAPIStructHeader*)next->pNext;
                 break;
             }
         }
@@ -612,10 +612,29 @@ VkResult MVKPhysicalDevice::getPhysicalDeviceMemoryProperties(VkPhysicalDeviceMe
 	return VK_SUCCESS;
 }
 
-VkResult MVKPhysicalDevice::getPhysicalDeviceMemoryProperties(VkPhysicalDeviceMemoryProperties2KHR* pMemoryProperties) {
+VkResult MVKPhysicalDevice::getPhysicalDeviceMemoryProperties(VkPhysicalDeviceMemoryProperties2* pMemoryProperties) {
 	if (pMemoryProperties) {
-		pMemoryProperties->sType = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MEMORY_PROPERTIES_2_KHR;
+		pMemoryProperties->sType = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MEMORY_PROPERTIES_2;
 		pMemoryProperties->memoryProperties = _memoryProperties;
+		auto* next = (MVKVkAPIStructHeader*)pMemoryProperties->pNext;
+		while (next) {
+			switch ((uint32_t)next->sType) {
+			case VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MEMORY_BUDGET_PROPERTIES_EXT: {
+				auto* budgetProps = (VkPhysicalDeviceMemoryBudgetPropertiesEXT*)next;
+				memset(budgetProps->heapBudget, 0, sizeof(budgetProps->heapBudget));
+				memset(budgetProps->heapUsage, 0, sizeof(budgetProps->heapUsage));
+				budgetProps->heapBudget[0] = (VkDeviceSize)mvkRecommendedMaxWorkingSetSize(_mtlDevice);
+				if ( [_mtlDevice respondsToSelector: @selector(currentAllocatedSize)] ) {
+					budgetProps->heapUsage[0] = (VkDeviceSize)_mtlDevice.currentAllocatedSize;
+				}
+				next = (MVKVkAPIStructHeader*)budgetProps->pNext;
+				break;
+			}
+			default:
+				next = (MVKVkAPIStructHeader*)next->pNext;
+				break;
+			}
+		}
 	}
 	return VK_SUCCESS;
 }

MoltenVK/MoltenVK/Layers/MVKExtensions.cpp

@@ -18,6 +18,7 @@
 
 #include "MVKExtensions.h"
 #include "MVKFoundation.h"
+#include "MVKOSExtensions.h"
 #include "vk_mvk_moltenvk.h"
 #include <vulkan/vulkan_ios.h>
 #include <vulkan/vulkan_macos.h>
@@ -103,11 +104,17 @@ string MVKExtensionList::enabledNamesString(const char* separator, bool prefixFi
 // Returns whether the specified properties are valid for this platform
 static bool mvkIsSupportedOnPlatform(VkExtensionProperties* pProperties) {
 #if !(MVK_IOS)
+	if (pProperties == &kVkExtProps_EXT_MEMORY_BUDGET) {
+		return mvkOSVersion() >= 10.13;
+	}
 	if (pProperties == &kVkExtProps_MVK_IOS_SURFACE) { return false; }
 	if (pProperties == &kVkExtProps_IMG_FORMAT_PVRTC) { return false; }
 #endif
 #if !(MVK_MACOS)
 	if (pProperties == &kVkExtProps_KHR_SAMPLER_MIRROR_CLAMP_TO_EDGE) { return false; }
+	if (pProperties == &kVkExtProps_EXT_MEMORY_BUDGET) {
+		return mvkOSVersion() >= 11.0;
+	}
 	if (pProperties == &kVkExtProps_MVK_MACOS_SURFACE) { return false; }
 #endif
 

MoltenVK/MoltenVK/Layers/MVKExtensions.def

@@ -51,6 +51,7 @@ MVK_EXTENSION(KHR_surface, KHR_SURFACE)
 MVK_EXTENSION(KHR_swapchain, KHR_SWAPCHAIN)
 MVK_EXTENSION(KHR_swapchain_mutable_format, KHR_SWAPCHAIN_MUTABLE_FORMAT)
 MVK_EXTENSION(KHR_variable_pointers, KHR_VARIABLE_POINTERS)
+MVK_EXTENSION(EXT_memory_budget, EXT_MEMORY_BUDGET)
 MVK_EXTENSION(EXT_shader_viewport_index_layer, EXT_SHADER_VIEWPORT_INDEX_LAYER)
 MVK_EXTENSION(EXT_vertex_attribute_divisor, EXT_VERTEX_ATTRIBUTE_DIVISOR)
 MVK_EXTENSION(EXTX_portability_subset, EXTX_PORTABILITY_SUBSET)

MoltenVK/MoltenVK/OS/MVKOSExtensions.h

@@ -22,7 +22,9 @@
 #include "MVKFoundation.h"
 #include <string>
 
+#ifdef __OBJC__
 #import <Metal/Metal.h>
+#endif
 
 
 typedef float MVKOSVersion;
@@ -59,6 +61,7 @@ double mvkGetTimestampPeriod();
  */
 double mvkGetElapsedMilliseconds(uint64_t startTimestamp = 0, uint64_t endTimestamp = 0);
 
+#ifdef __OBJC__
 /** Ensures the block is executed on the main thread. */
 inline void mvkDispatchToMainAndWait(dispatch_block_t block) {
 	if (NSThread.isMainThread) {
@@ -67,12 +70,14 @@ inline void mvkDispatchToMainAndWait(dispatch_block_t block) {
 		dispatch_sync(dispatch_get_main_queue(), block);
 	}
 }
+#endif
 
 
 #pragma mark -
 #pragma mark Process environment
 
 
+#ifdef __OBJC__
 /**
  * Returns the value of the environment variable at the given name,
  * or an empty string if no environment variable with that name exists.
@@ -130,11 +135,13 @@ inline bool mvkGetEnvVarBool(std::string varName, bool* pWasFound = nullptr) {
 		int64_t val = wasFound ? ev : EV;						\
 		cfgVal = (int32_t)mvkClamp(val, (int64_t)INT32_MIN, (int64_t)INT32_MAX);	\
 	} while(false)
+#endif
 
 
 #pragma mark -
 #pragma mark MTLDevice
 
+#ifdef __OBJC__
 /** Returns an approximation of how much memory, in bytes, the device can use with good performance. */
 uint64_t mvkRecommendedMaxWorkingSetSize(id<MTLDevice> mtlDevice);
 
@@ -147,3 +154,4 @@ void mvkPopulateGPUInfo(VkPhysicalDeviceProperties& devProps, id<MTLDevice> mtlD
  * The format must support linear texture memory (must not be depth, stencil, or compressed).
  */
 VkDeviceSize mvkMTLPixelFormatLinearTextureAlignment(MTLPixelFormat mtlPixelFormat, id<MTLDevice> mtlDevice);
+#endif