Merge pull request #2320 from billhollings/imgview-retain-img

Fix race condition when VkImage destroyed while used by descriptor.

Docs/Whats_New.md

@@ -27,6 +27,7 @@ Released TBD
   end of a descriptor binding count, including inline uniform block descriptors.
 - Update `VkFormat` capabilities based on latest Metal docs.
 - Fix rendering issue with render pass that immediately follows a kernel dispatch.
+- Fix race condition when `VkImage` destroyed while used by descriptor.
 - Ensure all MoltenVK config info set by `VK_EXT_layer_settings` is used.
 - Move primitive-restart-disabled warning from renderpass to pipeline creation, to reduce voluminous log noise.
 - iOS: Support storage images in _Metal_ argument buffers.

MoltenVK/MoltenVK/GPUObjects/MVKImage.mm

@@ -2194,6 +2194,8 @@ static void signalAndUntrack(const MVKSwapchainSignaler& signaler) {
 
 MVKImageView::MVKImageView(MVKDevice* device, const VkImageViewCreateInfo* pCreateInfo) : MVKVulkanAPIDeviceObject(device) {
 	_image = (MVKImage*)pCreateInfo->image;
+	_image->retain();		// Ensure image sticks around while this image view is in flight.
+
     _mtlTextureType = mvkMTLTextureTypeFromVkImageViewType(pCreateInfo->viewType,
 														   _image->getSampleCount() != VK_SAMPLE_COUNT_1_BIT);
 
@@ -2306,6 +2308,7 @@ static void signalAndUntrack(const MVKSwapchainSignaler& signaler) {
 // Memory detached in destructor too, as a fail-safe.
 MVKImageView::~MVKImageView() {
 	detachMemory();
+	_image->release();
 }
 
 // Overridden to detach from the resource memory when the app destroys this object.