Remove exposure to leakable instances of NSString, NSArray & NSDictionary.

Reduce creation of autoreleased instances of NSString, NSArray & NSDictionary.
Ensure remaining are covered by deliberate autorelease pools.

Common/MVKOSExtensions.mm

@@ -76,10 +76,12 @@ void mvkDispatchToMainAndWait(dispatch_block_t block) {
 #pragma mark Process environment
 
 string mvkGetEnvVar(string varName, bool* pWasFound) {
-	NSDictionary* env = [[NSProcessInfo processInfo] environment];
+	@autoreleasepool {
-	NSString* envStr = env[@(varName.c_str())];
+		NSDictionary*nsEnv = [[NSProcessInfo processInfo] environment];
+		NSString* envStr = nsEnv[@(varName.c_str())];
 		if (pWasFound) { *pWasFound = envStr != nil; }
 		return envStr ? envStr.UTF8String : "";
+	}
 }
 
 int64_t mvkGetEnvVarInt64(string varName, bool* pWasFound) {

Docs/Whats_New.md

@@ -31,6 +31,9 @@ Released TBD
 - Fix pipeline cache lookups.
 - Fix race condition between swapchain image destruction and presentation completion callback.
 - Set Metal texture usage to allow texture copy via view.
+- Fix memory leak in debug marker and debug utils labelling.
+- Reduce use of autoreleased Obj-C objects, and ensure those remaining are 
+  covered by deliberate autorelease pools. 
 - `vkCmdCopyImage()` support copying between compressed and uncompressed formats
   and validate that formats are compatible for copying.
 - `vkCmdBufferImageCopy()` fix crash when setting bytes per image in non-arrayed images.

MoltenVK/MoltenVK/Commands/MVKCommandResourceFactory.mm

@@ -399,7 +399,9 @@ id<MTLComputePipelineState> MVKCommandResourceFactory::newCmdCopyQueryPoolResult
 
 id<MTLFunction> MVKCommandResourceFactory::getFunctionNamed(const char* funcName) {
 	uint64_t startTime = _device->getPerformanceTimestamp();
-    id<MTLFunction> mtlFunc = [[_mtlLibrary newFunctionWithName: @(funcName)] autorelease];
+	NSString* nsFuncName = [[NSString alloc] initWithUTF8String: funcName];		// temp retained
+	id<MTLFunction> mtlFunc = [[_mtlLibrary newFunctionWithName: nsFuncName] autorelease];
+	[nsFuncName release];	// release temp NSStr
 	_device->addActivityPerformance(_device->_performanceStatistics.shaderCompilation.functionRetrieval, startTime);
 	return mtlFunc;
 }

MoltenVK/MoltenVK/GPUObjects/MVKImage.mm

@@ -372,6 +372,7 @@ VkResult MVKImage::useIOSurface(IOSurfaceRef ioSurface) {
     } else {
 #pragma clang diagnostic push
 #pragma clang diagnostic ignored "-Wdeprecated-declarations"
+		@autoreleasepool {
 			_ioSurface = IOSurfaceCreate((CFDictionaryRef)@{
 															(id)kIOSurfaceWidth: @(_extent.width),
 															(id)kIOSurfaceHeight: @(_extent.height),
@@ -380,6 +381,7 @@ VkResult MVKImage::useIOSurface(IOSurfaceRef ioSurface) {
 															(id)kIOSurfaceElementHeight: @(mvkMTLPixelFormatBlockTexelSize(_mtlPixelFormat).height),
 															(id)kIOSurfaceIsGlobal: @(true),    // Deprecated but needed for interprocess transfers
 															});
+		}
 #pragma clang diagnostic pop
 
     }

MoltenVK/MoltenVK/GPUObjects/MVKInstance.mm

@@ -252,28 +252,28 @@ VkDebugUtilsMessageSeverityFlagBitsEXT MVKInstance::getVkDebugUtilsMessageSeveri
 
 #pragma mark Object Creation
 
-// Returns an autoreleased array containing the MTLDevices available on this system,
+// Returns a new array containing the MTLDevices available on this system, sorted according to power,
-// sorted according to power, with higher power GPU's at the front of the array.
+// with higher power GPU's at the front of the array. This ensures that a lazy app that simply
-// This ensures that a lazy app that simply grabs the first GPU will get a high-power
+// grabs the first GPU will get a high-power one by default. If the MVK_CONFIG_FORCE_LOW_POWER_GPU
-// one by default. If the MVK_CONFIG_FORCE_LOW_POWER_GPU env var or build setting is set,
+// env var or build setting is set, the returned array will only include low-power devices.
-// the returned array will only include low-power devices.
+// It is the caller's responsibility to release the array when not required anymore.
-// If Metal is not supported, ensure we return an empty array.
+// If Metal is not supported, returns an empty array.
-static NSArray<id<MTLDevice>>* getAvailableMTLDevices() {
+static NSArray<id<MTLDevice>>* newAvailableMTLDevicesArray() {
-#if MVK_MACOS
+	NSMutableArray* mtlDevs = [NSMutableArray new];
-	NSArray* mtlDevs = [MTLCopyAllDevices() autorelease];
-	if ( !mtlDevs ) { return @[]; }
 
+#if MVK_MACOS
+	NSArray* rawMTLDevs = MTLCopyAllDevices();			// temp retain
+	if (rawMTLDevs) {
 		bool forceLowPower = MVK_CONFIG_FORCE_LOW_POWER_GPU;
 		MVK_SET_FROM_ENV_OR_BUILD_BOOL(forceLowPower, MVK_CONFIG_FORCE_LOW_POWER_GPU);
 
-	if (forceLowPower) {
+		// Populate the array of appropriate MTLDevices
-		NSMutableArray* lpDevs = [[NSMutableArray new] autorelease];
+		for (id<MTLDevice> md in rawMTLDevs) {
-		for (id<MTLDevice> md in mtlDevs) {
+			if ( !forceLowPower || md.isLowPower ) { [mtlDevs addObject: md]; }
-			if (md.isLowPower) { [lpDevs addObject: md]; }
 		}
-		return lpDevs;
+
-	} else {
+		// Sort by power
-		return [mtlDevs sortedArrayUsingComparator: ^(id<MTLDevice> md1, id<MTLDevice> md2) {
+		[mtlDevs sortUsingComparator: ^(id<MTLDevice> md1, id<MTLDevice> md2) {
 			BOOL md1IsLP = md1.isLowPower;
 			BOOL md2IsLP = md2.isLowPower;
 
@@ -290,14 +290,18 @@ static NSArray<id<MTLDevice>>* getAvailableMTLDevices() {
 
 			return md2IsLP ? NSOrderedAscending : NSOrderedDescending;
 		}];
-	}
 
+	}
+	[rawMTLDevs release];								// release temp
 #endif	// MVK_MACOS
 
 #if MVK_IOS
-	id<MTLDevice> mtlDev = MTLCreateSystemDefaultDevice();
+	id<MTLDevice> md = MTLCreateSystemDefaultDevice();
-	return mtlDev ? [NSArray arrayWithObject: mtlDev] : @[];
+	if (md) { [mtlDevs addObject: md]; }
+	[md release];
 #endif	// MVK_IOS
+
+	return mtlDevs;		// retained
 }
 
 MVKInstance::MVKInstance(const VkInstanceCreateInfo* pCreateInfo) : _enabledExtensions(this) {
@@ -326,11 +330,13 @@ MVKInstance::MVKInstance(const VkInstanceCreateInfo* pCreateInfo) : _enabledExte
 	}
 
 	// Populate the array of physical GPU devices
-	NSArray<id<MTLDevice>>* mtlDevices = getAvailableMTLDevices();
+	NSArray<id<MTLDevice>>* mtlDevices = newAvailableMTLDevicesArray();		// temp retain
 	_physicalDevices.reserve(mtlDevices.count);
 	for (id<MTLDevice> mtlDev in mtlDevices) {
 		_physicalDevices.push_back(new MVKPhysicalDevice(this, mtlDev));
 	}
+	[mtlDevices release];													// release temp
+
 	if (_physicalDevices.empty()) {
 		setConfigurationResult(reportError(VK_ERROR_INCOMPATIBLE_DRIVER, "Vulkan is not supported on this device. MoltenVK requires Metal, which is not available on this device."));
 	}

MoltenVK/MoltenVK/GPUObjects/MVKShaderModule.mm

@@ -49,10 +49,12 @@ MVKMTLFunction MVKShaderLibrary::getMTLFunction(const VkSpecializationInfo* pSpe
 
     if ( !_mtlLibrary ) { return MVKMTLFunctionNull; }
 
+	id<MTLFunction> mtlFunc = nil;
+	@autoreleasepool {
 		NSString* mtlFuncName = @(_shaderConversionResults.entryPoint.mtlFunctionName.c_str());
 		MVKDevice* mvkDev = _owner->getDevice();
 		uint64_t startTime = mvkDev->getPerformanceTimestamp();
-    id<MTLFunction> mtlFunc = [[_mtlLibrary newFunctionWithName: mtlFuncName] autorelease];
+		mtlFunc = [_mtlLibrary newFunctionWithName: mtlFuncName];	// retained
 		mvkDev->addActivityPerformance(mvkDev->_performanceStatistics.shaderCompilation.functionRetrieval, startTime);
 
 		if (mtlFunc) {
@@ -64,7 +66,7 @@ MVKMTLFunction MVKShaderLibrary::getMTLFunction(const VkSpecializationInfo* pSpe
 				if (mtlFCs.count) {
 					// The Metal shader contains function constants and expects to be specialized
 					// Populate the Metal function constant values from the Vulkan specialization info.
-                MTLFunctionConstantValues* mtlFCVals = [[MTLFunctionConstantValues new] autorelease];
+					MTLFunctionConstantValues* mtlFCVals = [MTLFunctionConstantValues new];		// temp retain
 					if (pSpecializationInfo) {
 						// Iterate through the provided Vulkan specialization entries, and populate the
 						// Metal function constant value that matches the Vulkan specialization constantID.
@@ -82,8 +84,9 @@ MVKMTLFunction MVKShaderLibrary::getMTLFunction(const VkSpecializationInfo* pSpe
 
 					// Compile the specialized Metal function, and use it instead of the unspecialized Metal function.
 					MVKFunctionSpecializer* fs = new MVKFunctionSpecializer(_owner);
-				mtlFunc = [fs->newMTLFunction(_mtlLibrary, mtlFuncName, mtlFCVals) autorelease];
+					mtlFunc = fs->newMTLFunction(_mtlLibrary, mtlFuncName, mtlFCVals);	// retained
 					fs->destroy();
+					[mtlFCVals release];		// release temp
 				}
 			}
 		} else {
@@ -94,10 +97,10 @@ MVKMTLFunction MVKShaderLibrary::getMTLFunction(const VkSpecializationInfo* pSpe
 		NSString* dbName = shaderModule-> getDebugName();
 		if ( !dbName ) { dbName = _owner-> getDebugName(); }
 		setLabelIfNotNil(mtlFunc, dbName);
-
+	}
 
 	auto& wgSize = _shaderConversionResults.entryPoint.workgroupSize;
-	return { mtlFunc, _shaderConversionResults, MTLSizeMake(getWorkgroupDimensionSize(wgSize.width, pSpecializationInfo),
+	return { [mtlFunc autorelease], _shaderConversionResults, MTLSizeMake(getWorkgroupDimensionSize(wgSize.width, pSpecializationInfo),
 																		  getWorkgroupDimensionSize(wgSize.height, pSpecializationInfo),
 																		  getWorkgroupDimensionSize(wgSize.depth, pSpecializationInfo))};
 }
@@ -124,7 +127,11 @@ MVKShaderLibrary::MVKShaderLibrary(MVKVulkanAPIDeviceObject* owner,
 								   const string& mslSourceCode,
 								   const SPIRVToMSLConversionResults& shaderConversionResults) : _owner(owner) {
 	MVKShaderLibraryCompiler* slc = new MVKShaderLibraryCompiler(_owner);
-	_mtlLibrary = slc->newMTLLibrary(@(mslSourceCode.c_str()));	// retained
+
+	NSString* nsSrc = [[NSString alloc] initWithUTF8String: mslSourceCode.c_str()];	// temp retained
+	_mtlLibrary = slc->newMTLLibrary(nsSrc);	// retained
+	[nsSrc release];	// release temp string
+
 	slc->destroy();
 
 	_shaderConversionResults = shaderConversionResults;

MoltenVK/MoltenVK/GPUObjects/MVKSwapchain.mm

@@ -38,7 +38,9 @@ void MVKSwapchain::propogateDebugName() {
 	if (_debugName) {
 		size_t imgCnt = _surfaceImages.size();
 		for (size_t imgIdx = 0; imgIdx < imgCnt; imgIdx++) {
-			_surfaceImages[imgIdx]->setDebugName([NSString stringWithFormat: @"%@(%lu)", _debugName, imgIdx].UTF8String);
+			NSString* nsName = [[NSString alloc] initWithFormat: @"%@(%lu)", _debugName, imgIdx];	// temp retain
+			_surfaceImages[imgIdx]->setDebugName(nsName.UTF8String);
+			[nsName release];																		// release temp string
 		}
 	}
 }

MoltenVK/MoltenVK/GPUObjects/MVKSync.mm

@@ -215,9 +215,11 @@ void MVKMetalCompiler::compile(unique_lock<mutex>& lock, dispatch_block_t block)
 	_blocker.wait_for(lock, nanoTimeout, [this]{ return _isCompileDone; });
 
 	if ( !_isCompileDone ) {
+		@autoreleasepool {
 			NSString* errDesc = [NSString stringWithFormat: @"Timeout after %.3f milliseconds. Likely internal Metal compiler error", (double)nanoTimeout.count() / 1e6];
 			_compileError = [[NSError alloc] initWithDomain: @"MoltenVK" code: 1 userInfo: @{NSLocalizedDescriptionKey : errDesc}];	// retained
 		}
+	}
 
 	if (_compileError) { handleError(); }
 

MoltenVK/MoltenVK/GPUObjects/MVKVulkanAPIObject.mm

@@ -39,7 +39,7 @@ void MVKVulkanAPIObject::destroy() {
 VkResult MVKVulkanAPIObject::setDebugName(const char* pObjectName) {
 	if (pObjectName) {
 		[_debugName release];
-		_debugName = [[NSString stringWithUTF8String: pObjectName] retain];		// retained
+		_debugName = [[NSString alloc] initWithUTF8String: pObjectName];	// retained
 		propogateDebugName();
 	}
 	return VK_SUCCESS;

MoltenVK/MoltenVK/OS/MVKGPUCapture.mm

@@ -59,8 +59,10 @@ void MVKGPUCaptureScope::makeDefault() {
 MVKGPUCaptureScope::MVKGPUCaptureScope(MVKQueue* mvkQueue, const char* purpose) : _queue(mvkQueue) {
 	_mtlQueue = [_queue->getMTLCommandQueue() retain];	// retained
 	if (mvkOSVersion() >= kMinOSVersionMTLCaptureScope) {
+		NSString* nsQLbl = [[NSString alloc] initWithUTF8String: (_queue->getName() + "-" + purpose).c_str()];		// temp retained
 		_mtlCaptureScope = [[MTLCaptureManager sharedCaptureManager] newCaptureScopeWithCommandQueue: _mtlQueue];	// retained
-		_mtlCaptureScope.label = @((_queue->getName() + "-" + purpose).c_str());
+		_mtlCaptureScope.label = nsQLbl;
+		[nsQLbl release];																							// release temp
 	}
 }
 

MoltenVK/MoltenVK/Utility/MVKWatermark.mm

@@ -304,9 +304,11 @@ void MVKWatermark::initTexture(unsigned char* textureContent,
 // Initialize the shader functions for rendering the watermark
 void MVKWatermark::initShaders(const char* mslSourceCode) {
     NSError* err = nil;
-    id<MTLLibrary> mtlLib = [[_mtlDevice newLibraryWithSource: @(mslSourceCode)
+	NSString* nsSrc = [[NSString alloc] initWithUTF8String: mslSourceCode];	// temp retained
+    id<MTLLibrary> mtlLib = [[_mtlDevice newLibraryWithSource: nsSrc
                                                       options: nil
                                                         error: &err] autorelease];
+	[nsSrc release];														// release temp string
 	MVKAssert( !err, "Could not compile watermark shaders (Error code %li):\n%s", (long)err.code, err.localizedDescription.UTF8String);
 
     _mtlFunctionVertex = [mtlLib newFunctionWithName: @"watermarkVertex"];          // retained