Add basic support for VK_KHR_external_semaphore{,_capabilities}.

Also a non-functional base for future extensions. We can't implement it
anyway until all remaining bugs in `MTLEvent`-based semaphores are
fixed.

This is the last of the extensions that was promoted to core for Vulkan
1.1. We're almost there!

Docs/Whats_New.md

@@ -23,6 +23,10 @@ Released TBD
 	  including support for GCD and Mach semaphores)
 	- `VK_KHR_external_fence_capabilities` (non-functional groundwork for future
 	  extensions, including support for GCD and Mach semaphores)
+	- `VK_KHR_external_semaphore` (non-functional groundwork for future
+	  `MTLSharedEvent` Vulkan extension)
+	- `VK_KHR_external_semaphore_capabilities` (non-functional groundwork for
+	  future `MTLSharedEvent` Vulkan extension)
 	- `VK_KHR_multiview`
 - Improve performance of tessellation control pipeline stage by processing multiple 
   patches per workgroup.

MoltenVK/MoltenVK/GPUObjects/MVKDevice.h

@@ -141,6 +141,10 @@ public:
 	void getExternalFenceProperties(const VkPhysicalDeviceExternalFenceInfo* pExternalFenceInfo,
 									VkExternalFenceProperties* pExternalFenceProperties);
 
+	/** Populates the external semaphore properties supported on this device. */
+	void getExternalSemaphoreProperties(const VkPhysicalDeviceExternalSemaphoreInfo* pExternalSemaphoreInfo,
+										VkExternalSemaphoreProperties* pExternalSemaphoreProperties);
+
 #pragma mark Surfaces
 
 	/**

MoltenVK/MoltenVK/GPUObjects/MVKDevice.mm

@@ -603,6 +603,15 @@ void MVKPhysicalDevice::getExternalFenceProperties(const VkPhysicalDeviceExterna
 	pExternalFenceProperties->pNext = next;
 }
 
+static const VkExternalSemaphoreProperties _emptyExtSemProps = {VK_STRUCTURE_TYPE_EXTERNAL_SEMAPHORE_PROPERTIES, nullptr, 0, 0, 0};
+
+void MVKPhysicalDevice::getExternalSemaphoreProperties(const VkPhysicalDeviceExternalSemaphoreInfo* pExternalSemaphoreInfo,
+													   VkExternalSemaphoreProperties* pExternalSemaphoreProperties) {
+	void* next = pExternalSemaphoreProperties->pNext;
+	*pExternalSemaphoreProperties = _emptyExtSemProps;
+	pExternalSemaphoreProperties->pNext = next;
+}
+
 
 #pragma mark Surfaces
 

MoltenVK/MoltenVK/GPUObjects/MVKInstance.mm

@@ -559,6 +559,7 @@ void MVKInstance::initProcAddrs() {
 	ADD_INST_EXT_ENTRY_POINT(vkEnumeratePhysicalDeviceGroupsKHR, KHR_DEVICE_GROUP_CREATION);
 	ADD_INST_EXT_ENTRY_POINT(vkGetPhysicalDeviceExternalFencePropertiesKHR, KHR_EXTERNAL_FENCE_CAPABILITIES);
 	ADD_INST_EXT_ENTRY_POINT(vkGetPhysicalDeviceExternalBufferPropertiesKHR, KHR_EXTERNAL_MEMORY_CAPABILITIES);
+	ADD_INST_EXT_ENTRY_POINT(vkGetPhysicalDeviceExternalSemaphorePropertiesKHR, KHR_EXTERNAL_SEMAPHORE_CAPABILITIES);
 	ADD_INST_EXT_ENTRY_POINT(vkGetPhysicalDeviceFeatures2KHR, KHR_GET_PHYSICAL_DEVICE_PROPERTIES_2);
 	ADD_INST_EXT_ENTRY_POINT(vkGetPhysicalDeviceProperties2KHR, KHR_GET_PHYSICAL_DEVICE_PROPERTIES_2);
 	ADD_INST_EXT_ENTRY_POINT(vkGetPhysicalDeviceFormatProperties2KHR, KHR_GET_PHYSICAL_DEVICE_PROPERTIES_2);

MoltenVK/MoltenVK/Layers/MVKExtensions.def

@@ -51,6 +51,8 @@ MVK_EXTENSION(KHR_external_fence, KHR_EXTERNAL_FENCE, DEVICE)
 MVK_EXTENSION(KHR_external_fence_capabilities, KHR_EXTERNAL_FENCE_CAPABILITIES, INSTANCE)
 MVK_EXTENSION(KHR_external_memory, KHR_EXTERNAL_MEMORY, DEVICE)
 MVK_EXTENSION(KHR_external_memory_capabilities, KHR_EXTERNAL_MEMORY_CAPABILITIES, INSTANCE)
+MVK_EXTENSION(KHR_external_semaphore, KHR_EXTERNAL_SEMAPHORE, DEVICE)
+MVK_EXTENSION(KHR_external_semaphore_capabilities, KHR_EXTERNAL_SEMAPHORE_CAPABILITIES, INSTANCE)
 MVK_EXTENSION(KHR_get_memory_requirements2, KHR_GET_MEMORY_REQUIREMENTS_2, DEVICE)
 MVK_EXTENSION(KHR_get_physical_device_properties2, KHR_GET_PHYSICAL_DEVICE_PROPERTIES_2, INSTANCE)
 MVK_EXTENSION(KHR_get_surface_capabilities2, KHR_GET_SURFACE_CAPABILITIES_2, INSTANCE)

MoltenVK/MoltenVK/Vulkan/vulkan.mm

@@ -2063,6 +2063,21 @@ MVK_PUBLIC_SYMBOL void vkGetPhysicalDeviceExternalBufferPropertiesKHR(
 }
 
 
+#pragma mark -
+#pragma mark VK_KHR_external_semaphore_capabilities extension
+
+MVK_PUBLIC_SYMBOL void vkGetPhysicalDeviceExternalSemaphorePropertiesKHR(
+	VkPhysicalDevice                             physicalDevice,
+	const VkPhysicalDeviceExternalSemaphoreInfo* pExternalSemaphoreInfo,
+	VkExternalSemaphoreProperties*               pExternalSemaphoreProperties) {
+
+	MVKTraceVulkanCallStart();
+	MVKPhysicalDevice* mvkPD = MVKPhysicalDevice::getMVKPhysicalDevice(physicalDevice);
+	mvkPD->getExternalSemaphoreProperties(pExternalSemaphoreInfo, pExternalSemaphoreProperties);
+	MVKTraceVulkanCallEnd();
+}
+
+
 #pragma mark -
 #pragma mark VK_KHR_get_memory_requirements2 extension