Fix occasional GPU crash when a smaller descriptor set replaces a lar…

…ger one.

If a descriptor set with fewer than 64 descriptors replaced one with more,
the resources it contained were not made resident to the GPU, due to
MVKBitArray thrashing incorrectly when transitioning between static and
dynamic memory allocations.

- Overhaul MVKBitArray design:
  - Never downsize memory allocation unless reset() is called.
  - No longer support static allocation for smaller sizes, to avoid thrashing
    between dynamic and static allocs when frequently resizing up and down.
  - Use realloc() instead of malloc/copy to improve performance.
  - Simplify tracking of partially and fully disabled sections.
  - Rename setXX() and clearXX() functions to enableXX() & disableXX().
  - Rename several internal functions.
  - getIndexOfFirstEnabledBit() & enumerateEnabledBits()
	no longer have an option to disable the bit.
- MVKDescriptorPool track highest descriptor set allocated,
  instead of querying MVKBitArray.

MoltenVK/MoltenVK/Commands/MVKCommandEncoderState.mm

@@ -645,7 +645,7 @@ - (void)setDepthBoundsTestAMD:(BOOL)enable minDepth:(float)minDepth maxDepth:(fl
 		if (dsChanged) {
 			auto& usageDirty = _metalUsageDirtyDescriptors[descSetIndex];
 			usageDirty.resize(descSet->getDescriptorCount());
-			usageDirty.setAllBits();
+			usageDirty.enableAllBits();
 		}
 
 		// Update dynamic buffer offsets
@@ -717,7 +717,7 @@ - (void)setDepthBoundsTestAMD:(BOOL)enable minDepth:(float)minDepth maxDepth:(fl
 	MVKCommandEncoderState::markDirty();
 	if (_cmdEncoder->isUsingMetalArgumentBuffers()) {
 		for (uint32_t dsIdx = 0; dsIdx < kMVKMaxDescriptorSetCount; dsIdx++) {
-			_metalUsageDirtyDescriptors[dsIdx].setAllBits();
+			_metalUsageDirtyDescriptors[dsIdx].enableAllBits();
 		}
 	}
 }

MoltenVK/MoltenVK/GPUObjects/MVKDescriptorSet.h

@@ -305,9 +305,9 @@ class MVKDescriptorPool : public MVKVulkanAPIDeviceObject {
 
 	MVKSmallVector<MVKDescriptorSet> _descriptorSets;
 	MVKBitArray _descriptorSetAvailablility;
-	id<MTLBuffer> _metalArgumentBuffer;
-	NSUInteger _nextMetalArgumentBufferOffset;
 	MVKMTLBufferAllocator _mtlBufferAllocator;
+	id<MTLBuffer> _metalArgumentBuffer = nil;
+	NSUInteger _nextMetalArgumentBufferOffset = 0;
 
 	MVKDescriptorTypePool<MVKUniformBufferDescriptor> _uniformBufferDescriptors;
 	MVKDescriptorTypePool<MVKStorageBufferDescriptor> _storageBufferDescriptors;
@@ -322,7 +322,8 @@ class MVKDescriptorPool : public MVKVulkanAPIDeviceObject {
 	MVKDescriptorTypePool<MVKUniformTexelBufferDescriptor> _uniformTexelBufferDescriptors;
 	MVKDescriptorTypePool<MVKStorageTexelBufferDescriptor> _storageTexelBufferDescriptors;
 
-	VkDescriptorPoolCreateFlags _flags;
+	VkDescriptorPoolCreateFlags _flags = 0;
+	size_t _maxAllocDescSetCount = 0;
 };
 
 

MoltenVK/MoltenVK/GPUObjects/MVKDescriptorSet.mm

@@ -292,7 +292,7 @@ static void populateAuxBuffer(mvk::SPIRVToMSLConversionConfiguration& shaderConf
 	for (uint32_t bindIdx = 0; bindIdx < bindCnt; bindIdx++) {
 		auto& dslBind = _bindings[bindIdx];
 		if (context.isResourceUsed(spvExecModels[stage], descSetIndex, dslBind.getBinding())) {
-			bindingUse.setBit(bindIdx);
+			bindingUse.enableBit(bindIdx);
 			descSetIsUsed = true;
 		}
 	}
@@ -628,9 +628,9 @@ static void populateAuxBuffer(mvk::SPIRVToMSLConversionConfiguration& shaderConf
 																	bool& dynamicAllocation,
 																	MVKDescriptorPool* pool) {
 	VkResult errRslt = VK_ERROR_OUT_OF_POOL_MEMORY;
-	size_t availDescIdx = _availability.getIndexOfFirstSetBit();
+	size_t availDescIdx = _availability.getIndexOfFirstEnabledBit();
 	if (availDescIdx < size()) {
-		_availability.clearBit(availDescIdx);		// Mark the descriptor as taken
+		_availability.disableBit(availDescIdx);		// Mark the descriptor as taken
 		*pMVKDesc = &_descriptors[availDescIdx];
 		(*pMVKDesc)->reset();						// Reset descriptor before reusing.
 		dynamicAllocation = false;
@@ -657,7 +657,7 @@ static void populateAuxBuffer(mvk::SPIRVToMSLConversionConfiguration& shaderConf
 	DescriptorClass* pFirstDesc = _descriptors.data();
 	int64_t descIdx = pDesc >= pFirstDesc ? pDesc - pFirstDesc : pFirstDesc - pDesc;
 	if (descIdx >= 0 && descIdx < size()) {
-		_availability.setBit(descIdx);
+		_availability.enableBit(descIdx);
 	} else {
 		mvkDesc->destroy();
 	}
@@ -666,13 +666,13 @@ static void populateAuxBuffer(mvk::SPIRVToMSLConversionConfiguration& shaderConf
 // Preallocated descriptors will be reset when they are reused
 template<typename DescriptorClass>
 void MVKDescriptorTypePool<DescriptorClass>::reset() {
-	_availability.setAllBits();
+	_availability.enableAllBits();
 }
 
 template<typename DescriptorClass>
 size_t MVKDescriptorTypePool<DescriptorClass>::getRemainingDescriptorCount() {
 	size_t enabledCount = 0;
-	_availability.enumerateEnabledBits(false, [&](size_t bitIdx) { enabledCount++; return true; });
+	_availability.enumerateEnabledBits([&](size_t bitIdx) { enabledCount++; return true; });
 	return enabledCount;
 }
 
@@ -740,7 +740,7 @@ static void populateAuxBuffer(mvk::SPIRVToMSLConversionConfiguration& shaderConf
 	uint64_t mtlArgBuffEncAlignedSize = mvkAlignByteCount(mtlArgBuffEncSize, getMetalFeatures().mtlBufferAlignment);
 
 	size_t dsCnt = _descriptorSetAvailablility.size();
-	_descriptorSetAvailablility.enumerateEnabledBits(true, [&](size_t dsIdx) {
+	_descriptorSetAvailablility.enumerateEnabledBits([&](size_t dsIdx) {
 		bool isSpaceAvail = true;		// If not using Metal arg buffers, space will always be available.
 		MVKDescriptorSet* mvkDS = &_descriptorSets[dsIdx];
 		NSUInteger mtlArgBuffOffset = mvkDS->getMetalArgumentBuffer().getMetalArgumentBufferOffset();
@@ -772,11 +772,12 @@ static void populateAuxBuffer(mvk::SPIRVToMSLConversionConfiguration& shaderConf
 			if (rslt) {
 				freeDescriptorSet(mvkDS, false);
 			} else {
+				_descriptorSetAvailablility.disableBit(dsIdx);
+				_maxAllocDescSetCount = std::max(_maxAllocDescSetCount, dsIdx + 1);
 				*pVKDS = (VkDescriptorSet)mvkDS;
 			}
 			return false;
 		} else {
-			_descriptorSetAvailablility.setBit(dsIdx);	// We didn't consume this one after all, so it's still available
 			return true;
 		}
 	});
@@ -800,7 +801,7 @@ static void populateAuxBuffer(mvk::SPIRVToMSLConversionConfiguration& shaderConf
 		mvkDS->free(isPoolReset);
 		if ( !isPoolReset ) {
 			size_t dsIdx = mvkDS - _descriptorSets.data();
-			_descriptorSetAvailablility.setBit(dsIdx);
+			_descriptorSetAvailablility.enableBit(dsIdx);
 		}
 	} else {
 		reportError(VK_ERROR_INITIALIZATION_FAILED, "A descriptor set is being returned to a descriptor pool that did not allocate it.");
@@ -810,11 +811,10 @@ static void populateAuxBuffer(mvk::SPIRVToMSLConversionConfiguration& shaderConf
 // Free allocated descriptor sets and reset descriptor pools.
 // Don't waste time freeing desc sets that were never allocated.
 VkResult MVKDescriptorPool::reset(VkDescriptorPoolResetFlags flags) {
-	size_t dsCnt = _descriptorSetAvailablility.getLowestNeverClearedBitIndex();
-	for (uint32_t dsIdx = 0; dsIdx < dsCnt; dsIdx++) {
+	for (uint32_t dsIdx = 0; dsIdx < _maxAllocDescSetCount; dsIdx++) {
 		freeDescriptorSet(&_descriptorSets[dsIdx], true);
 	}
-	_descriptorSetAvailablility.setAllBits();
+	_descriptorSetAvailablility.enableAllBits();
 
 	_uniformBufferDescriptors.reset();
 	_storageBufferDescriptors.reset();
@@ -830,6 +830,7 @@ static void populateAuxBuffer(mvk::SPIRVToMSLConversionConfiguration& shaderConf
 	_storageTexelBufferDescriptors.reset();
 
 	_nextMetalArgumentBufferOffset = 0;
+	_maxAllocDescSetCount = 0;
 
 	return VK_SUCCESS;
 }
@@ -1003,9 +1004,6 @@ static void populateAuxBuffer(mvk::SPIRVToMSLConversionConfiguration& shaderConf
 	}
 
 void MVKDescriptorPool::initMetalArgumentBuffer(const VkDescriptorPoolCreateInfo* pCreateInfo) {
-	_metalArgumentBuffer = nil;
-	_nextMetalArgumentBufferOffset = 0;
-
 	if ( !isUsingMetalArgumentBuffers() ) { return; }
 
 	auto& mtlFeats = getMetalFeatures();