[WebGPU] Sampler states across all argument buffers are unbounded

https://bugs.webkit.org/show_bug.cgi?id=275294 <radar://129227428> Reviewed by Dan Glastonbury. The max number of unique samplers allowed per process is -[MTLDevice maxArgumentBufferSamplerCount] which is currently 96 on most iOS devices and 1024 on many macOS devices. We need to ensure if we create more than the limit, we dealloc one so only samplers up to the limit are created. This doesn't interfer with WebGL as it only applies to samplers created with supportArgumentBuffers = YES. We can not easily set this flag to NO without avoiding ICBs which would come with substantial performance cost. * LayoutTests/fast/webgpu/nocrash/fuzz-275294-expected.txt: Added. * LayoutTests/fast/webgpu/nocrash/fuzz-275294.html: Added. Add regression test. * Source/WebCore/Modules/WebGPU/Implementation/WebGPUDeviceImpl.cpp: (WebCore::WebGPU::DeviceImpl::createSampler): * Source/WebGPU/WebGPU.xcodeproj/project.pbxproj: * Source/WebGPU/WebGPU/BindGroup.h: (WebGPU::BindGroup::create): * Source/WebGPU/WebGPU/BindGroup.mm: (WebGPU::Device::createBindGroup): (WebGPU::BindGroup::BindGroup): (WebGPU::BindGroup::rebindSamplersIfNeeded const): * Source/WebGPU/WebGPU/BindGroupLayout.h: * Source/WebGPU/WebGPU/ComputePassEncoder.mm: (WebGPU::ComputePassEncoder::executePreDispatchCommands): * Source/WebGPU/WebGPU/RenderPassEncoder.mm: (WebGPU::RenderPassEncoder::executePreDrawCommands): * Source/WebGPU/WebGPU/Sampler.h: (WebGPU::Sampler::create): (WebGPU::Sampler::isValid const): Deleted. (WebGPU::Sampler::samplerState const): Deleted. * Source/WebGPU/WebGPU/Sampler.mm: (-[SamplerIdentifier initWithFirst:second:]): (-[SamplerIdentifier copyWithZone:]): (WebGPU::miscHash): (WebGPU::floatToUint64): (WebGPU::computeDescriptorHash): (WebGPU::createMetalDescriptorFromDescriptor): (WebGPU::Device::createSampler): (WebGPU::Sampler::Sampler): (WebGPU::Sampler::setLabel): (WebGPU::Sampler::isValid const): (WebGPU::Sampler::samplerState const): (WebGPU::Sampler::cachedSampler const): * Source/WebGPU/WebGPU/ShaderStage.h: Added. * Source/WebGPU/WebGPU/WebGPU.h: Canonical link: https://commits.webkit.org/279893@main
WebKit · Jun 11, 2024 · 52423d2 · 52423d2
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diff --git a/LayoutTests/fast/webgpu/nocrash/fuzz-275294-expected.txt b/LayoutTests/fast/webgpu/nocrash/fuzz-275294-expected.txt
@@ -0,0 1,10 @@
 layer at (0,0) size 800x600
  RenderView at (0,0) size 800x600
 layer at (0,0) size 800x600
  RenderBlock {HTML} at (0,0) size 800x600 [color=#99DDBBCC] [bgcolor=#102030E0]
  RenderBody {BODY} at (8,8) size 784x584
  RenderImage {IMG} at (0,414) size 21x128
 layer at (29,8) size 748x542
  RenderHTMLCanvas {CANVAS} at (21,0) size 748x542
 layer at (8,550) size 16x16
  RenderVideo {VIDEO} at (0,542) size 16x16
diff --git a/LayoutTests/fast/webgpu/nocrash/fuzz-275294.html b/LayoutTests/fast/webgpu/nocrash/fuzz-275294.html
diff --git a/Source/WebCore/Modules/WebGPU/Implementation/WebGPUDeviceImpl.cpp b/Source/WebCore/Modules/WebGPU/Implementation/WebGPUDeviceImpl.cpp
@@ -137,21 137,19 @@ RefPtr<Texture> DeviceImpl::createTexture(const TextureDescriptor& descriptor)
 
 RefPtr<Sampler> DeviceImpl::createSampler(const SamplerDescriptor& descriptor)
 {
- auto label = descriptor.label.utf8();
-
  WGPUSamplerDescriptor backingDescriptor {
- nullptr,
- label.data(),
- m_convertToBackingContext->convertToBacking(descriptor.addressModeU),
- m_convertToBackingContext->convertToBacking(descriptor.addressModeV),
- m_convertToBackingContext->convertToBacking(descriptor.addressModeW),
- m_convertToBackingContext->convertToBacking(descriptor.magFilter),
- m_convertToBackingContext->convertToBacking(descriptor.minFilter),
- m_convertToBackingContext->convertToBacking(descriptor.mipmapFilter),
- descriptor.lodMinClamp,
- descriptor.lodMaxClamp,
- descriptor.compare ? m_convertToBackingContext->convertToBacking(*descriptor.compare) : WGPUCompareFunction_Undefined,
- descriptor.maxAnisotropy,
  .nextInChain = nullptr,
  .label = descriptor.label,
  .addressModeU = m_convertToBackingContext->convertToBacking(descriptor.addressModeU),
  .addressModeV = m_convertToBackingContext->convertToBacking(descriptor.addressModeV),
  .addressModeW = m_convertToBackingContext->convertToBacking(descriptor.addressModeW),
  .magFilter = m_convertToBackingContext->convertToBacking(descriptor.magFilter),
  .minFilter = m_convertToBackingContext->convertToBacking(descriptor.minFilter),
  .mipmapFilter = m_convertToBackingContext->convertToBacking(descriptor.mipmapFilter),
  .lodMinClamp = descriptor.lodMinClamp,
  .lodMaxClamp = descriptor.lodMaxClamp,
  .compare = descriptor.compare ? m_convertToBackingContext->convertToBacking(*descriptor.compare) : WGPUCompareFunction_Undefined,
  .maxAnisotropy = descriptor.maxAnisotropy,
  };
 
  return SamplerImpl::create(adoptWebGPU(wgpuDeviceCreateSampler(m_backing.get(), &backingDescriptor)), m_convertToBackingContext);

diff --git a/Source/WebGPU/WebGPU.xcodeproj/project.pbxproj b/Source/WebGPU/WebGPU.xcodeproj/project.pbxproj
@@ -12,6 12,7 @@
  0D30F93929F1FAC50055D9F1 /* ExternalTexture.h in Headers */ = {isa = PBXBuildFile; fileRef = 0D30F93829F1FAC50055D9F1 /* ExternalTexture.h */; };
  0D30F93B29F1FBE40055D9F1 /* CoreVideo.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 0D30F93A29F1FBE40055D9F1 /* CoreVideo.framework */; };
  0D509DCD29CAB6EC00546D84 /* MetalSPI.h in Headers */ = {isa = PBXBuildFile; fileRef = 0D509DCC29CAB6EC00546D84 /* MetalSPI.h */; };
  0DE2BFAD2C150DF700D04AEB /* ShaderStage.h in Headers */ = {isa = PBXBuildFile; fileRef = 0DE2BFAC2C150DF700D04AEB /* ShaderStage.h */; };
  1C0F41EE280940650005886D /* HardwareCapabilities.mm in Sources */ = {isa = PBXBuildFile; fileRef = 1C0F41EC280940650005886D /* HardwareCapabilities.mm */; };
  1C2CEDEE271E8A7300EDC16F /* Metal.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 1C2CEDED271E8A7300EDC16F /* Metal.framework */; };
  1C582FF927E04131009B40F0 /* CommandsMixin.mm in Sources */ = {isa = PBXBuildFile; fileRef = 1C582FF727E04131009B40F0 /* CommandsMixin.mm */; };
@@ -267,6 268,7 @@
  0D30F93A29F1FBE40055D9F1 /* CoreVideo.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = CoreVideo.framework; path = System/Library/Frameworks/CoreVideo.framework; sourceTree = SDKROOT; };
  0D4D2E80294A89CF0000A1AB /* BindableResource.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = BindableResource.h; sourceTree = "<group>"; };
  0D509DCC29CAB6EC00546D84 /* MetalSPI.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = MetalSPI.h; sourceTree = "<group>"; };
  0DE2BFAC2C150DF700D04AEB /* ShaderStage.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ShaderStage.h; sourceTree = "<group>"; };
  1C0F41EC280940650005886D /* HardwareCapabilities.mm */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.objcpp; path = HardwareCapabilities.mm; sourceTree = "<group>"; };
  1C0F41ED280940650005886D /* HardwareCapabilities.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = HardwareCapabilities.h; sourceTree = "<group>"; };
  1C2CEDED271E8A7300EDC16F /* Metal.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = Metal.framework; path = System/Library/Frameworks/Metal.framework; sourceTree = SDKROOT; };
@@ -619,6 621,7 @@
  1C5ACAE8273A55FD0095F8D5 /* Sampler.mm */,
  1CEBD80D2716C3D800A5254D /* ShaderModule.h */,
  1C5ACAB0273A426D0095F8D5 /* ShaderModule.mm */,
  0DE2BFAC2C150DF700D04AEB /* ShaderStage.h */,
  1C5ACA99273A426D0095F8D5 /* Texture.h */,
  1C5ACAB1273A426D0095F8D5 /* Texture.mm */,
  1C5ACADD273A4F3D0095F8D5 /* TextureView.h */,
@@ -843,6 846,7 @@
  0D30F93929F1FAC50055D9F1 /* ExternalTexture.h in Headers */,
  0D509DCD29CAB6EC00546D84 /* MetalSPI.h in Headers */,
  973F784729C8A78200166C66 /* Pipeline.h in Headers */,
  0DE2BFAD2C150DF700D04AEB /* ShaderStage.h in Headers */,
  1C5ACAD3273A4C860095F8D5 /* WebGPUExt.h in Headers */,
  );
  runOnlyForDeploymentPostprocessing = 0;

diff --git a/Source/WebGPU/WebGPU/BindGroup.h b/Source/WebGPU/WebGPU/BindGroup.h
@@ -26,6 26,7 @@
 #pragma once
 
 #import "BindableResource.h"
 #import "ShaderStage.h"
 #import <wtf/FastMalloc.h>
 #import <wtf/Ref.h>
 #import <wtf/RefCounted.h>
@@ -45,6 46,9 @@ class Sampler;
 class BindGroup : public WGPUBindGroupImpl, public RefCounted<BindGroup>, public CanMakeWeakPtr<BindGroup> {
  WTF_MAKE_FAST_ALLOCATED;
 public:
  template <typename T>
  using ShaderStageArray = EnumeratedArray<ShaderStage, T, ShaderStage::Compute>;
  using SamplersContainer = HashMap<RefPtr<Sampler>, ShaderStageArray<std::optional<uint32_t>>>;
  struct BufferAndType {
  WGPUBufferBindingType type;
  uint64_t bindingSize;
@@ -55,7 59,7 @@ class BindGroup : public WGPUBindGroupImpl, public RefCounted<BindGroup>, public
 
  static constexpr MTLRenderStages MTLRenderStageCompute = static_cast<MTLRenderStages>(0);
  static constexpr MTLRenderStages MTLRenderStageUndefined = static_cast<MTLRenderStages>(MTLRenderStageFragment 1);
- static Ref<BindGroup> create(id<MTLBuffer> vertexArgumentBuffer, id<MTLBuffer> fragmentArgumentBuffer, id<MTLBuffer> computeArgumentBuffer, Vector<BindableResources>&& resources, const BindGroupLayout& bindGroupLayout, DynamicBuffersContainer&& dynamicBuffers, HashSet<RefPtr<Sampler>>&& samplers, Device& device)
  static Ref<BindGroup> create(id<MTLBuffer> vertexArgumentBuffer, id<MTLBuffer> fragmentArgumentBuffer, id<MTLBuffer> computeArgumentBuffer, Vector<BindableResources>&& resources, const BindGroupLayout& bindGroupLayout, DynamicBuffersContainer&& dynamicBuffers, SamplersContainer&& samplers, Device& device)
  {
  return adoptRef(*new BindGroup(vertexArgumentBuffer, fragmentArgumentBuffer, computeArgumentBuffer, WTFMove(resources), bindGroupLayout, WTFMove(dynamicBuffers), WTFMove(samplers), device));
  }
@@ -84,8 88,10 @@ class BindGroup : public WGPUBindGroupImpl, public RefCounted<BindGroup>, public
  const BindGroupLayout* bindGroupLayout() const;
  const BufferAndType* dynamicBuffer(uint32_t) const;
  uint32_t dynamicOffset(uint32_t bindingIndex, const Vector<uint32_t>*) const;
  void rebindSamplersIfNeeded() const;
 
 private:
- BindGroup(id<MTLBuffer> vertexArgumentBuffer, id<MTLBuffer> fragmentArgumentBuffer, id<MTLBuffer> computeArgumentBuffer, Vector<BindableResources>&&, const BindGroupLayout&, DynamicBuffersContainer&&, HashSet<RefPtr<Sampler>>&&, Device&);
  BindGroup(id<MTLBuffer> vertexArgumentBuffer, id<MTLBuffer> fragmentArgumentBuffer, id<MTLBuffer> computeArgumentBuffer, Vector<BindableResources>&&, const BindGroupLayout&, DynamicBuffersContainer&&, SamplersContainer&&, Device&);
  BindGroup(Device&);
 
  const id<MTLBuffer> m_vertexArgumentBuffer { nil };
@@ -97,7 103,7 @@ class BindGroup : public WGPUBindGroupImpl, public RefCounted<BindGroup>, public
  RefPtr<const BindGroupLayout> m_bindGroupLayout;
  DynamicBuffersContainer m_dynamicBuffers;
  HashMap<uint32_t, uint32_t, DefaultHash<uint32_t>, WTF::UnsignedWithZeroKeyHashTraits<uint32_t>> m_dynamicOffsetsIndices;
- HashSet<RefPtr<Sampler>> m_samplers;
  SamplersContainer m_samplers;
 };
 
 } // namespace WebGPU
diff --git a/Source/WebGPU/WebGPU/BindGroup.mm b/Source/WebGPU/WebGPU/BindGroup.mm
@@ -77,9 77,6 @@ static MTLRenderStages metalRenderStage(ShaderStage shaderStage)
  }
 }
 
-template <typename T>
-using ShaderStageArray = EnumeratedArray<ShaderStage, T, ShaderStage::Compute>;
-
 #if HAVE(COREVIDEO_METAL_SUPPORT)
 
 enum class TransferFunctionCV {
@@ -902,8 899,8 @@ static BindGroupEntryUsageData makeBindGroupEntryUsageData(BindGroupEntryUsage u
  return BindGroup::createInvalid(*this);
  }
 
- ShaderStageArray<id<MTLArgumentEncoder>> argumentEncoder = std::array<id<MTLArgumentEncoder>, stageCount>({ bindGroupLayout.vertexArgumentEncoder(), bindGroupLayout.fragmentArgumentEncoder(), bindGroupLayout.computeArgumentEncoder() });
- ShaderStageArray<id<MTLBuffer>> argumentBuffer;
  BindGroup::ShaderStageArray<id<MTLArgumentEncoder>> argumentEncoder = std::array<id<MTLArgumentEncoder>, stageCount>({ bindGroupLayout.vertexArgumentEncoder(), bindGroupLayout.fragmentArgumentEncoder(), bindGroupLayout.computeArgumentEncoder() });
  BindGroup::ShaderStageArray<id<MTLBuffer>> argumentBuffer;
  for (ShaderStage stage : stages) {
  auto encodedLength = bindGroupLayout.encodedLength(stage);
  argumentBuffer[stage] = encodedLength ? safeCreateBuffer(encodedLength, MTLStorageModeShared) : nil;
@@ -920,7 917,7 @@ static BindGroupEntryUsageData makeBindGroupEntryUsageData(BindGroupEntryUsage u
  return a.binding < b.binding;
  });
  BindGroup::DynamicBuffersContainer dynamicBuffers;
- HashSet<RefPtr<Sampler>> samplersSet;
  BindGroup::SamplersContainer samplersSet;
 
  for (uint32_t i = 0, entryCount = descriptor.entryCount; i < entryCount; i) {
  const WGPUBindGroupEntry& entry = descriptor.entries[i];
@@ -1046,7 1043,7 @@ static BindGroupEntryUsageData makeBindGroupEntryUsageData(BindGroupEntryUsage u
  id<MTLSamplerState> sampler = apiSampler.samplerState();
  if (stage != ShaderStage::Undefined) {
  [argumentEncoder[stage] setSamplerState:sampler atIndex:index];
- samplersSet.add(&apiSampler);
  samplersSet.add(&apiSampler, BindGroup::ShaderStageArray<std::optional<uint32_t>> { }).iterator->value[stage] = index;
  }
  } else if (textureViewIsPresent) {
  auto it = bindGroupLayoutEntries.find(bindingIndex);
@@ -1184,7 1181,7 @@ static BindGroupEntryUsageData makeBindGroupEntryUsageData(BindGroupEntryUsage u
  return m_bindGroupLayout.get();
 }
 
-BindGroup::BindGroup(id<MTLBuffer> vertexArgumentBuffer, id<MTLBuffer> fragmentArgumentBuffer, id<MTLBuffer> computeArgumentBuffer, Vector<BindableResources>&& resources, const BindGroupLayout& bindGroupLayout, DynamicBuffersContainer&& dynamicBuffers, HashSet<RefPtr<Sampler>>&& samplers, Device& device)
 BindGroup::BindGroup(id<MTLBuffer> vertexArgumentBuffer, id<MTLBuffer> fragmentArgumentBuffer, id<MTLBuffer> computeArgumentBuffer, Vector<BindableResources>&& resources, const BindGroupLayout& bindGroupLayout, DynamicBuffersContainer&& dynamicBuffers, SamplersContainer&& samplers, Device& device)
  : m_vertexArgumentBuffer(vertexArgumentBuffer)
  , m_fragmentArgumentBuffer(fragmentArgumentBuffer)
  , m_computeArgumentBuffer(computeArgumentBuffer)
@@ -1277,6 1274,31 @@ static BindGroupEntryUsageData makeBindGroupEntryUsageData(BindGroupEntryUsage u
  return (static_cast<uint64_t>(aspect) - 1) | (static_cast<uint64_t>(baseMipLevel) << 1) | (static_cast<uint64_t>(baseArrayLayer) << 32);
 }
 
 void BindGroup::rebindSamplersIfNeeded() const
 {
  for (auto& [samplerRefPtr, shaderStageArray] : m_samplers) {
  auto* sampler = samplerRefPtr.get();
  ASSERT(sampler);
  if (!sampler || sampler->cachedSampler())
  continue;
 
  WTFLogAlways("Rebinding of samplers required, if this occurs frequently the application is using too many unique samplers");
  id<MTLSamplerState> samplerState = sampler->samplerState();
  if (shaderStageArray[ShaderStage::Vertex].has_value()) {
  [m_bindGroupLayout->vertexArgumentEncoder() setArgumentBuffer:vertexArgumentBuffer() offset:0];
  [m_bindGroupLayout->vertexArgumentEncoder() setSamplerState:samplerState atIndex:*shaderStageArray[ShaderStage::Vertex]];
  }
  if (shaderStageArray[ShaderStage::Fragment].has_value()) {
  [m_bindGroupLayout->fragmentArgumentEncoder() setArgumentBuffer:fragmentArgumentBuffer() offset:0];
  [m_bindGroupLayout->fragmentArgumentEncoder() setSamplerState:samplerState atIndex:*shaderStageArray[ShaderStage::Fragment]];
  }
  if (shaderStageArray[ShaderStage::Compute].has_value()) {
  [m_bindGroupLayout->computeArgumentEncoder() setArgumentBuffer:computeArgumentBuffer() offset:0];
  [m_bindGroupLayout->computeArgumentEncoder() setSamplerState:samplerState atIndex:*shaderStageArray[ShaderStage::Compute]];
  }
  }
 }
 
 } // namespace WebGPU
 
 #pragma mark WGPU Stubs

diff --git a/Source/WebGPU/WebGPU/BindGroupLayout.h b/Source/WebGPU/WebGPU/BindGroupLayout.h
@@ -25,6 25,7 @@
 
 #pragma once
 
 #import "ShaderStage.h"
 #import <wtf/EnumeratedArray.h>
 #import <wtf/FastMalloc.h>
 #import <wtf/HashMap.h>
@@ -39,13 40,6 @@ struct WGPUBindGroupLayoutImpl {
 
 namespace WebGPU {
 
-enum class ShaderStage {
- Vertex = 0,
- Fragment = 1,
- Compute = 2,
- Undefined = 3
-};
-
 class BindGroup;
 class Device;
 class PipelineLayout;

diff --git a/Source/WebGPU/WebGPU/ComputePassEncoder.mm b/Source/WebGPU/WebGPU/ComputePassEncoder.mm
@@ -179,6 179,7 @@ static bool addResourceToActiveResources(const BindGroupEntryUsageData::Resource
  return;
  }
  auto& group = *kvp.value.get();
  group.rebindSamplersIfNeeded();
  const Vector<uint32_t>* dynamicOffsets = nullptr;
  if (auto it = m_bindGroupDynamicOffsets.find(bindGroupIndex); it != m_bindGroupDynamicOffsets.end())
  dynamicOffsets = &it->value;

diff --git a/Source/WebGPU/WebGPU/RenderPassEncoder.mm b/Source/WebGPU/WebGPU/RenderPassEncoder.mm
@@ -499,6 499,7 @@ static void setViewportMinMaxDepthIntoBuffer(auto& fragmentDynamicOffsets, float
  return false;
  }
  auto& group = *weakBindGroup.get();
  group.rebindSamplersIfNeeded();
  const Vector<uint32_t>* dynamicOffsets = nullptr;
  if (auto it = m_bindGroupDynamicOffsets.find(groupIndex); it != m_bindGroupDynamicOffsets.end())
  dynamicOffsets = &it->value;

diff --git a/Source/WebGPU/WebGPU/Sampler.h b/Source/WebGPU/WebGPU/Sampler.h
@@ -32,6 32,14 @@
 struct WGPUSamplerImpl {
 };
 
 @interface SamplerIdentifier : NSObject<NSCopying>
 - (instancetype)initWithFirst:(uint64_t)first second:(uint64_t)second NS_DESIGNATED_INITIALIZER;
 - (instancetype)init NS_UNAVAILABLE;
 
 @property (nonatomic) uint64_t first;
 @property (nonatomic) uint64_t second;
 @end
 
 namespace WebGPU {
 
 class Device;
@@ -40,9 48,9 @@ class Device;
 class Sampler : public WGPUSamplerImpl, public RefCounted<Sampler> {
  WTF_MAKE_FAST_ALLOCATED;
 public:
- static Ref<Sampler> create(id<MTLSamplerState> samplerState, const WGPUSamplerDescriptor& descriptor, Device& device)
  static Ref<Sampler> create(SamplerIdentifier* samplerIdentifier, const WGPUSamplerDescriptor& descriptor, Device& device)
  {
- return adoptRef(*new Sampler(samplerState, descriptor, device));
  return adoptRef(*new Sampler(samplerIdentifier, descriptor, device));
  }
  static Ref<Sampler> createInvalid(Device& device)
  {
@@ -53,24 61,29 @@ class Sampler : public WGPUSamplerImpl, public RefCounted<Sampler> {
 
  void setLabel(String&&);
 
- bool isValid() const { return m_samplerState; }
  bool isValid() const;
 
- id<MTLSamplerState> samplerState() const { return m_samplerState; }
  id<MTLSamplerState> cachedSampler() const;
  id<MTLSamplerState> samplerState() const;
  const WGPUSamplerDescriptor& descriptor() const { return m_descriptor; }
  bool isComparison() const { return descriptor().compare != WGPUCompareFunction_Undefined; }
  bool isFiltering() const { return descriptor().minFilter == WGPUFilterMode_Linear || descriptor().magFilter == WGPUFilterMode_Linear || descriptor().mipmapFilter == WGPUMipmapFilterMode_Linear; }
 
  Device& device() const { return m_device; }
 
 private:
- Sampler(id<MTLSamplerState>, const WGPUSamplerDescriptor&, Device&);
  Sampler(SamplerIdentifier*, const WGPUSamplerDescriptor&, Device&);
  Sampler(Device&);
 
- const id<MTLSamplerState> m_samplerState { nil };
-
- const WGPUSamplerDescriptor m_descriptor { };
  SamplerIdentifier* m_samplerIdentifier { nil };
  WGPUSamplerDescriptor m_descriptor { };
 
  const Ref<Device> m_device;
  // static is intentional here as the limit is per process
  static NSMutableDictionary<SamplerIdentifier*, id<MTLSamplerState>> *cachedSamplerStates;
  static NSMutableOrderedSet<SamplerIdentifier*> *lastAccessedKeys;
 
  mutable __weak id<MTLSamplerState> m_cachedSamplerState { nil };
 };
 
 } // namespace WebGPU