src/dawn/tests/unittests/LimitsTests.cpp - dawn - Git at Google

 // Copyright 2021 The Dawn Authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.

 #include <gtest/gtest.h>

 #include "dawn/common/Constants.h"
 #include "dawn/native/Limits.h"

 namespace dawn {
 namespace {

 // Test |GetDefaultLimits| returns the default.
 TEST(Limits, GetDefaultLimits) {
     native::Limits limits = {};
     EXPECT_NE(limits.maxBindGroups, 4u);

     native::GetDefaultLimits(&limits);

     EXPECT_EQ(limits.maxBindGroups, 4u);
 }

 // Test |ReifyDefaultLimits| populates the default if
 // values are undefined.
 TEST(Limits, ReifyDefaultLimits_PopulatesDefault) {
     native::Limits limits;
     limits.maxComputeWorkgroupStorageSize = wgpu::kLimitU32Undefined;
     limits.maxStorageBufferBindingSize = wgpu::kLimitU64Undefined;

     native::Limits reified = native::ReifyDefaultLimits(limits);
     EXPECT_EQ(reified.maxComputeWorkgroupStorageSize, 16384u);
     EXPECT_EQ(reified.maxStorageBufferBindingSize, 134217728ul);
 }

 // Test |ReifyDefaultLimits| clamps to the default if
 // values are worse than the default.
 TEST(Limits, ReifyDefaultLimits_Clamps) {
     native::Limits limits;
     limits.maxStorageBuffersPerShaderStage = 4;
     limits.minUniformBufferOffsetAlignment = 512;

     native::Limits reified = native::ReifyDefaultLimits(limits);
     EXPECT_EQ(reified.maxStorageBuffersPerShaderStage, 8u);
     EXPECT_EQ(reified.minUniformBufferOffsetAlignment, 256u);
 }

 // Test |ValidateLimits| works to validate limits are not better
 // than supported.
 TEST(Limits, ValidateLimits) {
     // Start with the default for supported.
     native::Limits defaults;
     native::GetDefaultLimits(&defaults);

     // Test supported == required is valid.
     {
         native::Limits required = defaults;
         EXPECT_TRUE(ValidateLimits(defaults, required).IsSuccess());
     }

     // Test supported == required is valid, when they are not default.
     {
         native::Limits supported = defaults;
         native::Limits required = defaults;
         supported.maxBindGroups += 1;
         required.maxBindGroups += 1;
         EXPECT_TRUE(ValidateLimits(supported, required).IsSuccess());
     }

     // Test that default-initialized (all undefined) is valid.
     {
         native::Limits required = {};
         EXPECT_TRUE(ValidateLimits(defaults, required).IsSuccess());
     }

     // Test that better than supported is invalid for "maximum" limits.
     {
         native::Limits required = {};
         required.maxTextureDimension3D = defaults.maxTextureDimension3D + 1;
         native::MaybeError err = ValidateLimits(defaults, required);
         EXPECT_TRUE(err.IsError());
         err.AcquireError();
     }

     // Test that worse than supported is valid for "maximum" limits.
     {
         native::Limits required = {};
         required.maxComputeWorkgroupSizeX = defaults.maxComputeWorkgroupSizeX - 1;
         EXPECT_TRUE(ValidateLimits(defaults, required).IsSuccess());
     }

     // Test that better than min is invalid for "alignment" limits.
     {
         native::Limits required = {};
         required.minUniformBufferOffsetAlignment = defaults.minUniformBufferOffsetAlignment / 2;
         native::MaybeError err = ValidateLimits(defaults, required);
         EXPECT_TRUE(err.IsError());
         err.AcquireError();
     }

     // Test that worse than min and a power of two is valid for "alignment" limits.
     {
         native::Limits required = {};
         required.minStorageBufferOffsetAlignment = defaults.minStorageBufferOffsetAlignment * 2;
         EXPECT_TRUE(ValidateLimits(defaults, required).IsSuccess());
     }

     // Test that worse than min and not a power of two is invalid for "alignment" limits.
     {
         native::Limits required = {};
         required.minStorageBufferOffsetAlignment = defaults.minStorageBufferOffsetAlignment * 3;
         native::MaybeError err = ValidateLimits(defaults, required);
         EXPECT_TRUE(err.IsError());
         err.AcquireError();
     }
 }

 // Test that |ApplyLimitTiers| degrades limits to the next best tier.
 TEST(Limits, ApplyLimitTiers) {
     auto SetLimitsStorageBufferBindingSizeTier2 = [](native::Limits* limits) {
         // Tier 2 of maxStorageBufferBindingSize is 1GB
         limits->maxStorageBufferBindingSize = 1073741824;
         // Also set the maxBufferSize to be large enough, as ApplyLimitTiers ensures tired
         // maxStorageBufferBindingSize no larger than tiered maxBufferSize.
         limits->maxBufferSize = 2147483648;
     };
     native::Limits limitsStorageBufferBindingSizeTier2;
     native::GetDefaultLimits(&limitsStorageBufferBindingSizeTier2);
     SetLimitsStorageBufferBindingSizeTier2(&limitsStorageBufferBindingSizeTier2);

     auto SetLimitsStorageBufferBindingSizeTier3 = [](native::Limits* limits) {
         // Tier 3 of maxStorageBufferBindingSize is 2GB-4
         limits->maxStorageBufferBindingSize = 2147483644;
         // Also set the maxBufferSize to be large enough, as ApplyLimitTiers ensures tired
         // maxStorageBufferBindingSize no larger than tiered maxBufferSize.
         limits->maxBufferSize = 2147483648;
     };
     native::Limits limitsStorageBufferBindingSizeTier3;
     native::GetDefaultLimits(&limitsStorageBufferBindingSizeTier3);
     SetLimitsStorageBufferBindingSizeTier3(&limitsStorageBufferBindingSizeTier3);

     auto SetLimitsComputeWorkgroupStorageSizeTier1 = [](native::Limits* limits) {
         limits->maxComputeWorkgroupStorageSize = 16384;
     };
     native::Limits limitsComputeWorkgroupStorageSizeTier1;
     native::GetDefaultLimits(&limitsComputeWorkgroupStorageSizeTier1);
     SetLimitsComputeWorkgroupStorageSizeTier1(&limitsComputeWorkgroupStorageSizeTier1);

     auto SetLimitsComputeWorkgroupStorageSizeTier3 = [](native::Limits* limits) {
         limits->maxComputeWorkgroupStorageSize = 65536;
     };
     native::Limits limitsComputeWorkgroupStorageSizeTier3;
     native::GetDefaultLimits(&limitsComputeWorkgroupStorageSizeTier3);
     SetLimitsComputeWorkgroupStorageSizeTier3(&limitsComputeWorkgroupStorageSizeTier3);

     // Test that applying tiers to limits that are exactly
     // equal to a tier returns the same values.
     {
         native::Limits limits = limitsStorageBufferBindingSizeTier2;
         EXPECT_EQ(ApplyLimitTiers(limits), limits);

         limits = limitsStorageBufferBindingSizeTier3;
         EXPECT_EQ(ApplyLimitTiers(limits), limits);
     }

     // Test all limits slightly worse than tier 3.
     {
         native::Limits limits = limitsStorageBufferBindingSizeTier3;
         limits.maxStorageBufferBindingSize -= 1;
         EXPECT_EQ(ApplyLimitTiers(limits), limitsStorageBufferBindingSizeTier2);
     }

     // Test that limits may match one tier exactly and be degraded in another tier.
     // Degrading to one tier does not affect the other tier.
     {
         native::Limits limits = limitsComputeWorkgroupStorageSizeTier3;
         // Set tier 3 and change one limit to be insufficent.
         SetLimitsStorageBufferBindingSizeTier3(&limits);
         limits.maxStorageBufferBindingSize -= 1;

         native::Limits tiered = ApplyLimitTiers(limits);

         // Check that |tiered| has the limits of memorySize tier 2
         native::Limits tieredWithMemorySizeTier2 = tiered;
         SetLimitsStorageBufferBindingSizeTier2(&tieredWithMemorySizeTier2);
         EXPECT_EQ(tiered, tieredWithMemorySizeTier2);

         // Check that |tiered| has the limits of bindingSpace tier 3
         native::Limits tieredWithBindingSpaceTier3 = tiered;
         SetLimitsComputeWorkgroupStorageSizeTier3(&tieredWithBindingSpaceTier3);
         EXPECT_EQ(tiered, tieredWithBindingSpaceTier3);
     }

     // Test that limits may be simultaneously degraded in two tiers independently.
     {
         native::Limits limits;
         native::GetDefaultLimits(&limits);
         SetLimitsComputeWorkgroupStorageSizeTier3(&limits);
         SetLimitsStorageBufferBindingSizeTier3(&limits);
         limits.maxComputeWorkgroupStorageSize =
             limitsComputeWorkgroupStorageSizeTier1.maxComputeWorkgroupStorageSize + 1;
         limits.maxStorageBufferBindingSize =
             limitsStorageBufferBindingSizeTier2.maxStorageBufferBindingSize + 1;

         native::Limits tiered = ApplyLimitTiers(limits);

         native::Limits expected = tiered;
         SetLimitsComputeWorkgroupStorageSizeTier1(&expected);
         SetLimitsStorageBufferBindingSizeTier2(&expected);
         EXPECT_EQ(tiered, expected);
     }
 }

 // Test that |ApplyLimitTiers| will hold the maxStorageBufferBindingSize no larger than
 // maxBufferSize restriction.
 TEST(Limits, TieredMaxStorageBufferBindingSizeNoLargerThanMaxBufferSize) {
     // Start with the default for supported.
     native::Limits defaults;
     native::GetDefaultLimits(&defaults);

     // Test reported maxStorageBufferBindingSize around 128MB, 1GB, 2GB-4 and 4GB-4.
     constexpr uint64_t storageSizeTier1 = 134217728ull;   // 128MB
     constexpr uint64_t storageSizeTier2 = 1073741824ull;  // 1GB
     constexpr uint64_t storageSizeTier3 = 2147483644ull;  // 2GB-4
     constexpr uint64_t storageSizeTier4 = 4294967292ull;  // 4GB-4
     constexpr uint64_t possibleReportedMaxStorageBufferBindingSizes[] = {
         storageSizeTier1,     storageSizeTier1 + 1, storageSizeTier2 - 1, storageSizeTier2,
         storageSizeTier2 + 1, storageSizeTier3 - 1, storageSizeTier3,     storageSizeTier3 + 1,
         storageSizeTier4 - 1, storageSizeTier4,     storageSizeTier4 + 1};
     // Test reported maxBufferSize around 256MB, 1GB, 2GB and 4GB, and a large 256GB.
     constexpr uint64_t bufferSizeTier1 = 0x10000000ull;    // 256MB
     constexpr uint64_t bufferSizeTier2 = 0x40000000ull;    // 1GB
     constexpr uint64_t bufferSizeTier3 = 0x80000000ull;    // 2GB
     constexpr uint64_t bufferSizeTier4 = 0x100000000ull;   // 4GB
     constexpr uint64_t bufferSizeLarge = 0x4000000000ull;  // 256GB
     constexpr uint64_t possibleReportedMaxBufferSizes[] = {
         bufferSizeTier1,     bufferSizeTier1 + 1, bufferSizeTier2 - 1, bufferSizeTier2,
         bufferSizeTier2 + 1, bufferSizeTier3 - 1, bufferSizeTier3,     bufferSizeTier3 + 1,
         bufferSizeTier4 - 1, bufferSizeTier4,     bufferSizeTier4 + 1, bufferSizeLarge};

     // Test that tiered maxStorageBufferBindingSize is no larger than tiered maxBufferSize.
     for (uint64_t reportedMaxStorageBufferBindingSizes :
          possibleReportedMaxStorageBufferBindingSizes) {
         for (uint64_t reportedMaxBufferSizes : possibleReportedMaxBufferSizes) {
             native::Limits limits = defaults;
             limits.maxStorageBufferBindingSize = reportedMaxStorageBufferBindingSizes;
             limits.maxBufferSize = reportedMaxBufferSizes;

             native::Limits tiered = ApplyLimitTiers(limits);

             EXPECT_LE(tiered.maxStorageBufferBindingSize, tiered.maxBufferSize);
         }
     }
 }

 // Test that |ApplyLimitTiers| will hold the maxUniformBufferBindingSize no larger than
 // maxBufferSize restriction.
 TEST(Limits, TieredMaxUniformBufferBindingSizeNoLargerThanMaxBufferSize) {
     // Start with the default for supported.
     native::Limits defaults;
     native::GetDefaultLimits(&defaults);

     // Test reported maxStorageBufferBindingSize around 64KB, and a large 1GB.
     constexpr uint64_t uniformSizeTier1 = 65536ull;       // 64KB
     constexpr uint64_t uniformSizeLarge = 1073741824ull;  // 1GB
     constexpr uint64_t possibleReportedMaxUniformBufferBindingSizes[] = {
         uniformSizeTier1, uniformSizeTier1 + 1, uniformSizeLarge};
     // Test reported maxBufferSize around 256MB, 1GB, 2GB and 4GB, and a large 256GB.
     constexpr uint64_t bufferSizeTier1 = 0x10000000ull;    // 256MB
     constexpr uint64_t bufferSizeTier2 = 0x40000000ull;    // 1GB
     constexpr uint64_t bufferSizeTier3 = 0x80000000ull;    // 2GB
     constexpr uint64_t bufferSizeTier4 = 0x100000000ull;   // 4GB
     constexpr uint64_t bufferSizeLarge = 0x4000000000ull;  // 256GB
     constexpr uint64_t possibleReportedMaxBufferSizes[] = {
         bufferSizeTier1,     bufferSizeTier1 + 1, bufferSizeTier2 - 1, bufferSizeTier2,
         bufferSizeTier2 + 1, bufferSizeTier3 - 1, bufferSizeTier3,     bufferSizeTier3 + 1,
         bufferSizeTier4 - 1, bufferSizeTier4,     bufferSizeTier4 + 1, bufferSizeLarge};

     // Test that tiered maxUniformBufferBindingSize is no larger than tiered maxBufferSize.
     for (uint64_t reportedMaxUniformBufferBindingSizes :
          possibleReportedMaxUniformBufferBindingSizes) {
         for (uint64_t reportedMaxBufferSizes : possibleReportedMaxBufferSizes) {
             native::Limits limits = defaults;
             limits.maxUniformBufferBindingSize = reportedMaxUniformBufferBindingSizes;
             limits.maxBufferSize = reportedMaxBufferSizes;

             native::Limits tiered = ApplyLimitTiers(limits);

             EXPECT_LE(tiered.maxUniformBufferBindingSize, tiered.maxBufferSize);
         }
     }
 }

 // Test |NormalizeLimits| works to enforce restriction of limits.
 TEST(Limits, NormalizeLimits) {
     // Start with the default for supported.
     native::Limits defaults;
     native::GetDefaultLimits(&defaults);

     // Test specific limit values are clamped to internal Dawn constants.
     {
         native::Limits limits = defaults;
         limits.maxVertexBufferArrayStride = kMaxVertexBufferArrayStride + 1;
         limits.maxColorAttachments = uint32_t(kMaxColorAttachments) + 1;
         limits.maxBindGroups = kMaxBindGroups + 1;
         limits.maxBindGroupsPlusVertexBuffers = kMaxBindGroupsPlusVertexBuffers + 1;
         limits.maxVertexAttributes = uint32_t(kMaxVertexAttributes) + 1;
         limits.maxVertexBuffers = uint32_t(kMaxVertexBuffers) + 1;
         limits.maxInterStageShaderComponents = kMaxInterStageShaderComponents + 1;
         limits.maxSampledTexturesPerShaderStage = kMaxSampledTexturesPerShaderStage + 1;
         limits.maxSamplersPerShaderStage = kMaxSamplersPerShaderStage + 1;
         limits.maxStorageBuffersPerShaderStage = kMaxStorageBuffersPerShaderStage + 1;
         limits.maxStorageTexturesPerShaderStage = kMaxStorageTexturesPerShaderStage + 1;
         limits.maxUniformBuffersPerShaderStage = kMaxUniformBuffersPerShaderStage + 1;

         NormalizeLimits(&limits);

         EXPECT_EQ(limits.maxVertexBufferArrayStride, kMaxVertexBufferArrayStride);
         EXPECT_EQ(limits.maxColorAttachments, uint32_t(kMaxColorAttachments));
         EXPECT_EQ(limits.maxBindGroups, kMaxBindGroups);
         EXPECT_EQ(limits.maxBindGroupsPlusVertexBuffers, kMaxBindGroupsPlusVertexBuffers);
         EXPECT_EQ(limits.maxVertexAttributes, uint32_t(kMaxVertexAttributes));
         EXPECT_EQ(limits.maxVertexBuffers, uint32_t(kMaxVertexBuffers));
         EXPECT_EQ(limits.maxInterStageShaderComponents, kMaxInterStageShaderComponents);
         EXPECT_EQ(limits.maxSampledTexturesPerShaderStage, kMaxSampledTexturesPerShaderStage);
         EXPECT_EQ(limits.maxSamplersPerShaderStage, kMaxSamplersPerShaderStage);
         EXPECT_EQ(limits.maxStorageBuffersPerShaderStage, kMaxStorageBuffersPerShaderStage);
         EXPECT_EQ(limits.maxStorageTexturesPerShaderStage, kMaxStorageTexturesPerShaderStage);
         EXPECT_EQ(limits.maxUniformBuffersPerShaderStage, kMaxUniformBuffersPerShaderStage);
     }

     // Test maxStorageBufferBindingSize is clamped to maxBufferSize.
     // maxStorageBufferBindingSize is no larger than maxBufferSize
     {
         constexpr uint64_t reportedMaxBufferSize = 2147483648;
         constexpr uint64_t reportedMaxStorageBufferBindingSize = reportedMaxBufferSize;
         native::Limits limits = defaults;
         limits.maxStorageBufferBindingSize = reportedMaxStorageBufferBindingSize;
         limits.maxBufferSize = reportedMaxBufferSize;

         NormalizeLimits(&limits);

         EXPECT_EQ(limits.maxBufferSize, reportedMaxBufferSize);
         EXPECT_EQ(limits.maxStorageBufferBindingSize, reportedMaxStorageBufferBindingSize);
     }
     {
         constexpr uint64_t reportedMaxBufferSize = 2147483648;
         constexpr uint64_t reportedMaxStorageBufferBindingSize = reportedMaxBufferSize - 1;
         native::Limits limits = defaults;
         limits.maxStorageBufferBindingSize = reportedMaxStorageBufferBindingSize;
         limits.maxBufferSize = reportedMaxBufferSize;

         NormalizeLimits(&limits);

         EXPECT_EQ(limits.maxBufferSize, reportedMaxBufferSize);
         EXPECT_EQ(limits.maxStorageBufferBindingSize, reportedMaxStorageBufferBindingSize);
     }
     // maxStorageBufferBindingSize is equal to maxBufferSize+1, expect clamping to maxBufferSize
     {
         constexpr uint64_t reportedMaxBufferSize = 2147483648;
         constexpr uint64_t reportedMaxStorageBufferBindingSize = reportedMaxBufferSize + 1;
         native::Limits limits = defaults;
         limits.maxStorageBufferBindingSize = reportedMaxStorageBufferBindingSize;
         limits.maxBufferSize = reportedMaxBufferSize;

         NormalizeLimits(&limits);

         EXPECT_EQ(limits.maxBufferSize, reportedMaxBufferSize);
         EXPECT_EQ(limits.maxStorageBufferBindingSize, reportedMaxBufferSize);
     }
     // maxStorageBufferBindingSize is much larger than maxBufferSize, expect clamping to
     // maxBufferSize
     {
         constexpr uint64_t reportedMaxBufferSize = 2147483648;
         constexpr uint64_t reportedMaxStorageBufferBindingSize = 4294967295;
         native::Limits limits = defaults;
         limits.maxStorageBufferBindingSize = reportedMaxStorageBufferBindingSize;
         limits.maxBufferSize = reportedMaxBufferSize;

         NormalizeLimits(&limits);

         EXPECT_EQ(limits.maxBufferSize, reportedMaxBufferSize);
         EXPECT_EQ(limits.maxStorageBufferBindingSize, reportedMaxBufferSize);
     }

     // Test maxUniformBufferBindingSize is clamped to maxBufferSize.
     // maxUniformBufferBindingSize is no larger than maxBufferSize
     {
         constexpr uint64_t reportedMaxBufferSize = 2147483648;
         constexpr uint64_t reportedMaxUniformBufferBindingSize = reportedMaxBufferSize - 1;
         native::Limits limits = defaults;
         limits.maxUniformBufferBindingSize = reportedMaxUniformBufferBindingSize;
         limits.maxBufferSize = reportedMaxBufferSize;

         NormalizeLimits(&limits);

         EXPECT_EQ(limits.maxBufferSize, reportedMaxBufferSize);
         EXPECT_EQ(limits.maxUniformBufferBindingSize, reportedMaxUniformBufferBindingSize);
     }
     {
         constexpr uint64_t reportedMaxBufferSize = 2147483648;
         constexpr uint64_t reportedMaxUniformBufferBindingSize = reportedMaxBufferSize;
         native::Limits limits = defaults;
         limits.maxUniformBufferBindingSize = reportedMaxUniformBufferBindingSize;
         limits.maxBufferSize = reportedMaxBufferSize;

         NormalizeLimits(&limits);

         EXPECT_EQ(limits.maxBufferSize, reportedMaxBufferSize);
         EXPECT_EQ(limits.maxUniformBufferBindingSize, reportedMaxUniformBufferBindingSize);
     }
     // maxUniformBufferBindingSize is larger than maxBufferSize, expect clamping to maxBufferSize
     {
         constexpr uint64_t reportedMaxBufferSize = 2147483648;
         constexpr uint64_t reportedMaxUniformBufferBindingSize = reportedMaxBufferSize + 1;
         native::Limits limits = defaults;
         limits.maxUniformBufferBindingSize = reportedMaxUniformBufferBindingSize;
         limits.maxBufferSize = reportedMaxBufferSize;

         NormalizeLimits(&limits);

         EXPECT_EQ(limits.maxBufferSize, reportedMaxBufferSize);
         EXPECT_EQ(limits.maxUniformBufferBindingSize, reportedMaxBufferSize);
     }
     // maxUniformBufferBindingSize is much larger than maxBufferSize, expect clamping to
     // maxBufferSize
     {
         constexpr uint64_t reportedMaxBufferSize = 2147483648;
         constexpr uint64_t reportedMaxUniformBufferBindingSize = 4294967295;
         native::Limits limits = defaults;
         limits.maxUniformBufferBindingSize = reportedMaxUniformBufferBindingSize;
         limits.maxBufferSize = reportedMaxBufferSize;

         NormalizeLimits(&limits);

         EXPECT_EQ(limits.maxBufferSize, reportedMaxBufferSize);
         EXPECT_EQ(limits.maxUniformBufferBindingSize, reportedMaxBufferSize);
     }
 }

 }  // anonymous namespace
 }  // namespace dawn
	// Copyright 2021 The Dawn Authors
	//
	// Licensed under the Apache License, Version 2.0 (the "License");
	// you may not use this file except in compliance with the License.
	// You may obtain a copy of the License at
	//
	// http://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing, software
	// distributed under the License is distributed on an "AS IS" BASIS,
	// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	// See the License for the specific language governing permissions and
	// limitations under the License.

	#include <gtest/gtest.h>

	#include "dawn/common/Constants.h"
	#include "dawn/native/Limits.h"

	namespace dawn {
	namespace {

	// Test \|GetDefaultLimits\| returns the default.
	TEST(Limits, GetDefaultLimits) {
	native::Limits limits = {};
	EXPECT_NE(limits.maxBindGroups, 4u);

	native::GetDefaultLimits(&limits);

	EXPECT_EQ(limits.maxBindGroups, 4u);
	}

	// Test \|ReifyDefaultLimits\| populates the default if
	// values are undefined.
	TEST(Limits, ReifyDefaultLimits_PopulatesDefault) {
	native::Limits limits;
	limits.maxComputeWorkgroupStorageSize = wgpu::kLimitU32Undefined;
	limits.maxStorageBufferBindingSize = wgpu::kLimitU64Undefined;

	native::Limits reified = native::ReifyDefaultLimits(limits);
	EXPECT_EQ(reified.maxComputeWorkgroupStorageSize, 16384u);
	EXPECT_EQ(reified.maxStorageBufferBindingSize, 134217728ul);
	}

	// Test \|ReifyDefaultLimits\| clamps to the default if
	// values are worse than the default.
	TEST(Limits, ReifyDefaultLimits_Clamps) {
	native::Limits limits;
	limits.maxStorageBuffersPerShaderStage = 4;
	limits.minUniformBufferOffsetAlignment = 512;

	native::Limits reified = native::ReifyDefaultLimits(limits);
	EXPECT_EQ(reified.maxStorageBuffersPerShaderStage, 8u);
	EXPECT_EQ(reified.minUniformBufferOffsetAlignment, 256u);
	}

	// Test \|ValidateLimits\| works to validate limits are not better
	// than supported.
	TEST(Limits, ValidateLimits) {
	// Start with the default for supported.
	native::Limits defaults;
	native::GetDefaultLimits(&defaults);

	// Test supported == required is valid.
	{
	native::Limits required = defaults;
	EXPECT_TRUE(ValidateLimits(defaults, required).IsSuccess());
	}

	// Test supported == required is valid, when they are not default.
	{
	native::Limits supported = defaults;
	native::Limits required = defaults;
	supported.maxBindGroups += 1;
	required.maxBindGroups += 1;
	EXPECT_TRUE(ValidateLimits(supported, required).IsSuccess());
	}

	// Test that default-initialized (all undefined) is valid.
	{
	native::Limits required = {};
	EXPECT_TRUE(ValidateLimits(defaults, required).IsSuccess());
	}

	// Test that better than supported is invalid for "maximum" limits.
	{
	native::Limits required = {};
	required.maxTextureDimension3D = defaults.maxTextureDimension3D + 1;
	native::MaybeError err = ValidateLimits(defaults, required);
	EXPECT_TRUE(err.IsError());
	err.AcquireError();
	}

	// Test that worse than supported is valid for "maximum" limits.
	{
	native::Limits required = {};
	required.maxComputeWorkgroupSizeX = defaults.maxComputeWorkgroupSizeX - 1;
	EXPECT_TRUE(ValidateLimits(defaults, required).IsSuccess());
	}

	// Test that better than min is invalid for "alignment" limits.
	{
	native::Limits required = {};
	required.minUniformBufferOffsetAlignment = defaults.minUniformBufferOffsetAlignment / 2;
	native::MaybeError err = ValidateLimits(defaults, required);
	EXPECT_TRUE(err.IsError());
	err.AcquireError();
	}

	// Test that worse than min and a power of two is valid for "alignment" limits.
	{
	native::Limits required = {};
	required.minStorageBufferOffsetAlignment = defaults.minStorageBufferOffsetAlignment * 2;
	EXPECT_TRUE(ValidateLimits(defaults, required).IsSuccess());
	}

	// Test that worse than min and not a power of two is invalid for "alignment" limits.
	{
	native::Limits required = {};
	required.minStorageBufferOffsetAlignment = defaults.minStorageBufferOffsetAlignment * 3;
	native::MaybeError err = ValidateLimits(defaults, required);
	EXPECT_TRUE(err.IsError());
	err.AcquireError();
	}
	}

	// Test that \|ApplyLimitTiers\| degrades limits to the next best tier.
	TEST(Limits, ApplyLimitTiers) {
	auto SetLimitsStorageBufferBindingSizeTier2 = [](native::Limits* limits) {
	// Tier 2 of maxStorageBufferBindingSize is 1GB
	limits->maxStorageBufferBindingSize = 1073741824;
	// Also set the maxBufferSize to be large enough, as ApplyLimitTiers ensures tired
	// maxStorageBufferBindingSize no larger than tiered maxBufferSize.
	limits->maxBufferSize = 2147483648;
	};
	native::Limits limitsStorageBufferBindingSizeTier2;
	native::GetDefaultLimits(&limitsStorageBufferBindingSizeTier2);
	SetLimitsStorageBufferBindingSizeTier2(&limitsStorageBufferBindingSizeTier2);

	auto SetLimitsStorageBufferBindingSizeTier3 = [](native::Limits* limits) {
	// Tier 3 of maxStorageBufferBindingSize is 2GB-4
	limits->maxStorageBufferBindingSize = 2147483644;
	// Also set the maxBufferSize to be large enough, as ApplyLimitTiers ensures tired
	// maxStorageBufferBindingSize no larger than tiered maxBufferSize.
	limits->maxBufferSize = 2147483648;
	};
	native::Limits limitsStorageBufferBindingSizeTier3;
	native::GetDefaultLimits(&limitsStorageBufferBindingSizeTier3);
	SetLimitsStorageBufferBindingSizeTier3(&limitsStorageBufferBindingSizeTier3);

	auto SetLimitsComputeWorkgroupStorageSizeTier1 = [](native::Limits* limits) {
	limits->maxComputeWorkgroupStorageSize = 16384;
	};
	native::Limits limitsComputeWorkgroupStorageSizeTier1;
	native::GetDefaultLimits(&limitsComputeWorkgroupStorageSizeTier1);
	SetLimitsComputeWorkgroupStorageSizeTier1(&limitsComputeWorkgroupStorageSizeTier1);

	auto SetLimitsComputeWorkgroupStorageSizeTier3 = [](native::Limits* limits) {
	limits->maxComputeWorkgroupStorageSize = 65536;
	};
	native::Limits limitsComputeWorkgroupStorageSizeTier3;
	native::GetDefaultLimits(&limitsComputeWorkgroupStorageSizeTier3);
	SetLimitsComputeWorkgroupStorageSizeTier3(&limitsComputeWorkgroupStorageSizeTier3);

	// Test that applying tiers to limits that are exactly
	// equal to a tier returns the same values.
	{
	native::Limits limits = limitsStorageBufferBindingSizeTier2;
	EXPECT_EQ(ApplyLimitTiers(limits), limits);

	limits = limitsStorageBufferBindingSizeTier3;
	EXPECT_EQ(ApplyLimitTiers(limits), limits);
	}

	// Test all limits slightly worse than tier 3.
	{
	native::Limits limits = limitsStorageBufferBindingSizeTier3;
	limits.maxStorageBufferBindingSize -= 1;
	EXPECT_EQ(ApplyLimitTiers(limits), limitsStorageBufferBindingSizeTier2);
	}

	// Test that limits may match one tier exactly and be degraded in another tier.
	// Degrading to one tier does not affect the other tier.
	{
	native::Limits limits = limitsComputeWorkgroupStorageSizeTier3;
	// Set tier 3 and change one limit to be insufficent.
	SetLimitsStorageBufferBindingSizeTier3(&limits);
	limits.maxStorageBufferBindingSize -= 1;

	native::Limits tiered = ApplyLimitTiers(limits);

	// Check that \|tiered\| has the limits of memorySize tier 2
	native::Limits tieredWithMemorySizeTier2 = tiered;
	SetLimitsStorageBufferBindingSizeTier2(&tieredWithMemorySizeTier2);
	EXPECT_EQ(tiered, tieredWithMemorySizeTier2);

	// Check that \|tiered\| has the limits of bindingSpace tier 3
	native::Limits tieredWithBindingSpaceTier3 = tiered;
	SetLimitsComputeWorkgroupStorageSizeTier3(&tieredWithBindingSpaceTier3);
	EXPECT_EQ(tiered, tieredWithBindingSpaceTier3);
	}

	// Test that limits may be simultaneously degraded in two tiers independently.
	{
	native::Limits limits;
	native::GetDefaultLimits(&limits);
	SetLimitsComputeWorkgroupStorageSizeTier3(&limits);
	SetLimitsStorageBufferBindingSizeTier3(&limits);
	limits.maxComputeWorkgroupStorageSize =
	limitsComputeWorkgroupStorageSizeTier1.maxComputeWorkgroupStorageSize + 1;
	limits.maxStorageBufferBindingSize =
	limitsStorageBufferBindingSizeTier2.maxStorageBufferBindingSize + 1;

	native::Limits tiered = ApplyLimitTiers(limits);

	native::Limits expected = tiered;
	SetLimitsComputeWorkgroupStorageSizeTier1(&expected);
	SetLimitsStorageBufferBindingSizeTier2(&expected);
	EXPECT_EQ(tiered, expected);
	}
	}

	// Test that \|ApplyLimitTiers\| will hold the maxStorageBufferBindingSize no larger than
	// maxBufferSize restriction.
	TEST(Limits, TieredMaxStorageBufferBindingSizeNoLargerThanMaxBufferSize) {
	// Start with the default for supported.
	native::Limits defaults;
	native::GetDefaultLimits(&defaults);

	// Test reported maxStorageBufferBindingSize around 128MB, 1GB, 2GB-4 and 4GB-4.
	constexpr uint64_t storageSizeTier1 = 134217728ull; // 128MB
	constexpr uint64_t storageSizeTier2 = 1073741824ull; // 1GB
	constexpr uint64_t storageSizeTier3 = 2147483644ull; // 2GB-4
	constexpr uint64_t storageSizeTier4 = 4294967292ull; // 4GB-4
	constexpr uint64_t possibleReportedMaxStorageBufferBindingSizes[] = {
	storageSizeTier1, storageSizeTier1 + 1, storageSizeTier2 - 1, storageSizeTier2,
	storageSizeTier2 + 1, storageSizeTier3 - 1, storageSizeTier3, storageSizeTier3 + 1,
	storageSizeTier4 - 1, storageSizeTier4, storageSizeTier4 + 1};
	// Test reported maxBufferSize around 256MB, 1GB, 2GB and 4GB, and a large 256GB.
	constexpr uint64_t bufferSizeTier1 = 0x10000000ull; // 256MB
	constexpr uint64_t bufferSizeTier2 = 0x40000000ull; // 1GB
	constexpr uint64_t bufferSizeTier3 = 0x80000000ull; // 2GB
	constexpr uint64_t bufferSizeTier4 = 0x100000000ull; // 4GB
	constexpr uint64_t bufferSizeLarge = 0x4000000000ull; // 256GB
	constexpr uint64_t possibleReportedMaxBufferSizes[] = {
	bufferSizeTier1, bufferSizeTier1 + 1, bufferSizeTier2 - 1, bufferSizeTier2,
	bufferSizeTier2 + 1, bufferSizeTier3 - 1, bufferSizeTier3, bufferSizeTier3 + 1,
	bufferSizeTier4 - 1, bufferSizeTier4, bufferSizeTier4 + 1, bufferSizeLarge};

	// Test that tiered maxStorageBufferBindingSize is no larger than tiered maxBufferSize.
	for (uint64_t reportedMaxStorageBufferBindingSizes :
	possibleReportedMaxStorageBufferBindingSizes) {
	for (uint64_t reportedMaxBufferSizes : possibleReportedMaxBufferSizes) {
	native::Limits limits = defaults;
	limits.maxStorageBufferBindingSize = reportedMaxStorageBufferBindingSizes;
	limits.maxBufferSize = reportedMaxBufferSizes;

	native::Limits tiered = ApplyLimitTiers(limits);

	EXPECT_LE(tiered.maxStorageBufferBindingSize, tiered.maxBufferSize);
	}
	}
	}

	// Test that \|ApplyLimitTiers\| will hold the maxUniformBufferBindingSize no larger than
	// maxBufferSize restriction.
	TEST(Limits, TieredMaxUniformBufferBindingSizeNoLargerThanMaxBufferSize) {
	// Start with the default for supported.
	native::Limits defaults;
	native::GetDefaultLimits(&defaults);

	// Test reported maxStorageBufferBindingSize around 64KB, and a large 1GB.
	constexpr uint64_t uniformSizeTier1 = 65536ull; // 64KB
	constexpr uint64_t uniformSizeLarge = 1073741824ull; // 1GB
	constexpr uint64_t possibleReportedMaxUniformBufferBindingSizes[] = {
	uniformSizeTier1, uniformSizeTier1 + 1, uniformSizeLarge};
	// Test reported maxBufferSize around 256MB, 1GB, 2GB and 4GB, and a large 256GB.
	constexpr uint64_t bufferSizeTier1 = 0x10000000ull; // 256MB
	constexpr uint64_t bufferSizeTier2 = 0x40000000ull; // 1GB
	constexpr uint64_t bufferSizeTier3 = 0x80000000ull; // 2GB
	constexpr uint64_t bufferSizeTier4 = 0x100000000ull; // 4GB
	constexpr uint64_t bufferSizeLarge = 0x4000000000ull; // 256GB
	constexpr uint64_t possibleReportedMaxBufferSizes[] = {
	bufferSizeTier1, bufferSizeTier1 + 1, bufferSizeTier2 - 1, bufferSizeTier2,
	bufferSizeTier2 + 1, bufferSizeTier3 - 1, bufferSizeTier3, bufferSizeTier3 + 1,
	bufferSizeTier4 - 1, bufferSizeTier4, bufferSizeTier4 + 1, bufferSizeLarge};

	// Test that tiered maxUniformBufferBindingSize is no larger than tiered maxBufferSize.
	for (uint64_t reportedMaxUniformBufferBindingSizes :
	possibleReportedMaxUniformBufferBindingSizes) {
	for (uint64_t reportedMaxBufferSizes : possibleReportedMaxBufferSizes) {
	native::Limits limits = defaults;
	limits.maxUniformBufferBindingSize = reportedMaxUniformBufferBindingSizes;
	limits.maxBufferSize = reportedMaxBufferSizes;

	native::Limits tiered = ApplyLimitTiers(limits);

	EXPECT_LE(tiered.maxUniformBufferBindingSize, tiered.maxBufferSize);
	}
	}
	}

	// Test \|NormalizeLimits\| works to enforce restriction of limits.
	TEST(Limits, NormalizeLimits) {
	// Start with the default for supported.
	native::Limits defaults;
	native::GetDefaultLimits(&defaults);

	// Test specific limit values are clamped to internal Dawn constants.
	{
	native::Limits limits = defaults;
	limits.maxVertexBufferArrayStride = kMaxVertexBufferArrayStride + 1;
	limits.maxColorAttachments = uint32_t(kMaxColorAttachments) + 1;
	limits.maxBindGroups = kMaxBindGroups + 1;
	limits.maxBindGroupsPlusVertexBuffers = kMaxBindGroupsPlusVertexBuffers + 1;
	limits.maxVertexAttributes = uint32_t(kMaxVertexAttributes) + 1;
	limits.maxVertexBuffers = uint32_t(kMaxVertexBuffers) + 1;
	limits.maxInterStageShaderComponents = kMaxInterStageShaderComponents + 1;
	limits.maxSampledTexturesPerShaderStage = kMaxSampledTexturesPerShaderStage + 1;
	limits.maxSamplersPerShaderStage = kMaxSamplersPerShaderStage + 1;
	limits.maxStorageBuffersPerShaderStage = kMaxStorageBuffersPerShaderStage + 1;
	limits.maxStorageTexturesPerShaderStage = kMaxStorageTexturesPerShaderStage + 1;
	limits.maxUniformBuffersPerShaderStage = kMaxUniformBuffersPerShaderStage + 1;

	NormalizeLimits(&limits);

	EXPECT_EQ(limits.maxVertexBufferArrayStride, kMaxVertexBufferArrayStride);
	EXPECT_EQ(limits.maxColorAttachments, uint32_t(kMaxColorAttachments));
	EXPECT_EQ(limits.maxBindGroups, kMaxBindGroups);
	EXPECT_EQ(limits.maxBindGroupsPlusVertexBuffers, kMaxBindGroupsPlusVertexBuffers);
	EXPECT_EQ(limits.maxVertexAttributes, uint32_t(kMaxVertexAttributes));
	EXPECT_EQ(limits.maxVertexBuffers, uint32_t(kMaxVertexBuffers));
	EXPECT_EQ(limits.maxInterStageShaderComponents, kMaxInterStageShaderComponents);
	EXPECT_EQ(limits.maxSampledTexturesPerShaderStage, kMaxSampledTexturesPerShaderStage);
	EXPECT_EQ(limits.maxSamplersPerShaderStage, kMaxSamplersPerShaderStage);
	EXPECT_EQ(limits.maxStorageBuffersPerShaderStage, kMaxStorageBuffersPerShaderStage);
	EXPECT_EQ(limits.maxStorageTexturesPerShaderStage, kMaxStorageTexturesPerShaderStage);
	EXPECT_EQ(limits.maxUniformBuffersPerShaderStage, kMaxUniformBuffersPerShaderStage);
	}

	// Test maxStorageBufferBindingSize is clamped to maxBufferSize.
	// maxStorageBufferBindingSize is no larger than maxBufferSize
	{
	constexpr uint64_t reportedMaxBufferSize = 2147483648;
	constexpr uint64_t reportedMaxStorageBufferBindingSize = reportedMaxBufferSize;
	native::Limits limits = defaults;
	limits.maxStorageBufferBindingSize = reportedMaxStorageBufferBindingSize;
	limits.maxBufferSize = reportedMaxBufferSize;

	NormalizeLimits(&limits);

	EXPECT_EQ(limits.maxBufferSize, reportedMaxBufferSize);
	EXPECT_EQ(limits.maxStorageBufferBindingSize, reportedMaxStorageBufferBindingSize);
	}
	{
	constexpr uint64_t reportedMaxBufferSize = 2147483648;
	constexpr uint64_t reportedMaxStorageBufferBindingSize = reportedMaxBufferSize - 1;
	native::Limits limits = defaults;
	limits.maxStorageBufferBindingSize = reportedMaxStorageBufferBindingSize;
	limits.maxBufferSize = reportedMaxBufferSize;

	NormalizeLimits(&limits);

	EXPECT_EQ(limits.maxBufferSize, reportedMaxBufferSize);
	EXPECT_EQ(limits.maxStorageBufferBindingSize, reportedMaxStorageBufferBindingSize);
	}
	// maxStorageBufferBindingSize is equal to maxBufferSize+1, expect clamping to maxBufferSize
	{
	constexpr uint64_t reportedMaxBufferSize = 2147483648;
	constexpr uint64_t reportedMaxStorageBufferBindingSize = reportedMaxBufferSize + 1;
	native::Limits limits = defaults;
	limits.maxStorageBufferBindingSize = reportedMaxStorageBufferBindingSize;
	limits.maxBufferSize = reportedMaxBufferSize;

	NormalizeLimits(&limits);

	EXPECT_EQ(limits.maxBufferSize, reportedMaxBufferSize);
	EXPECT_EQ(limits.maxStorageBufferBindingSize, reportedMaxBufferSize);
	}
	// maxStorageBufferBindingSize is much larger than maxBufferSize, expect clamping to
	// maxBufferSize
	{
	constexpr uint64_t reportedMaxBufferSize = 2147483648;
	constexpr uint64_t reportedMaxStorageBufferBindingSize = 4294967295;
	native::Limits limits = defaults;
	limits.maxStorageBufferBindingSize = reportedMaxStorageBufferBindingSize;
	limits.maxBufferSize = reportedMaxBufferSize;

	NormalizeLimits(&limits);

	EXPECT_EQ(limits.maxBufferSize, reportedMaxBufferSize);
	EXPECT_EQ(limits.maxStorageBufferBindingSize, reportedMaxBufferSize);
	}

	// Test maxUniformBufferBindingSize is clamped to maxBufferSize.
	// maxUniformBufferBindingSize is no larger than maxBufferSize
	{
	constexpr uint64_t reportedMaxBufferSize = 2147483648;
	constexpr uint64_t reportedMaxUniformBufferBindingSize = reportedMaxBufferSize - 1;
	native::Limits limits = defaults;
	limits.maxUniformBufferBindingSize = reportedMaxUniformBufferBindingSize;
	limits.maxBufferSize = reportedMaxBufferSize;

	NormalizeLimits(&limits);

	EXPECT_EQ(limits.maxBufferSize, reportedMaxBufferSize);
	EXPECT_EQ(limits.maxUniformBufferBindingSize, reportedMaxUniformBufferBindingSize);
	}
	{
	constexpr uint64_t reportedMaxBufferSize = 2147483648;
	constexpr uint64_t reportedMaxUniformBufferBindingSize = reportedMaxBufferSize;
	native::Limits limits = defaults;
	limits.maxUniformBufferBindingSize = reportedMaxUniformBufferBindingSize;
	limits.maxBufferSize = reportedMaxBufferSize;

	NormalizeLimits(&limits);

	EXPECT_EQ(limits.maxBufferSize, reportedMaxBufferSize);
	EXPECT_EQ(limits.maxUniformBufferBindingSize, reportedMaxUniformBufferBindingSize);
	}
	// maxUniformBufferBindingSize is larger than maxBufferSize, expect clamping to maxBufferSize
	{
	constexpr uint64_t reportedMaxBufferSize = 2147483648;
	constexpr uint64_t reportedMaxUniformBufferBindingSize = reportedMaxBufferSize + 1;
	native::Limits limits = defaults;
	limits.maxUniformBufferBindingSize = reportedMaxUniformBufferBindingSize;
	limits.maxBufferSize = reportedMaxBufferSize;

	NormalizeLimits(&limits);

	EXPECT_EQ(limits.maxBufferSize, reportedMaxBufferSize);
	EXPECT_EQ(limits.maxUniformBufferBindingSize, reportedMaxBufferSize);
	}
	// maxUniformBufferBindingSize is much larger than maxBufferSize, expect clamping to
	// maxBufferSize
	{
	constexpr uint64_t reportedMaxBufferSize = 2147483648;
	constexpr uint64_t reportedMaxUniformBufferBindingSize = 4294967295;
	native::Limits limits = defaults;
	limits.maxUniformBufferBindingSize = reportedMaxUniformBufferBindingSize;
	limits.maxBufferSize = reportedMaxBufferSize;

	NormalizeLimits(&limits);

	EXPECT_EQ(limits.maxBufferSize, reportedMaxBufferSize);
	EXPECT_EQ(limits.maxUniformBufferBindingSize, reportedMaxBufferSize);
	}
	}

	} // anonymous namespace
	} // namespace dawn