SPIRV-Tools/test/fuzz/transformation_add_dead_block_test.cpp
Alastair Donaldson 8013d477ae
spirv-fuzz: add dead blocks (#3135)
This adds a new kind of fact to the fact manager that knows whether a
block is dead - i.e. guaranteed to be statically unreachable - and a
new transformation for adding a selection construct to a CFG that
conditionally branches to a fresh, dead block, such that the branch
will never be dynamically taken. Transformations that may create new
blocks ('split block' and 'outline function') are updated to propagate
dead block facts to newly-created blocks where appropriate. A fuzzer
pass randomly adds dead blocks to the module.

Future transformations will be able to exploit the fact that such
blocks are known to be dead.
2020-01-13 22:04:01 +00:00

322 lines
10 KiB
C++

// Copyright (c) 2019 Google LLC
//
// 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 "source/fuzz/transformation_add_dead_block.h"
#include "test/fuzz/fuzz_test_util.h"
namespace spvtools {
namespace fuzz {
namespace {
TEST(TransformationAddDeadBlockTest, BasicTest) {
std::string shader = R"(
OpCapability Shader
%1 = OpExtInstImport "GLSL.std.450"
OpMemoryModel Logical GLSL450
OpEntryPoint Fragment %4 "main"
OpExecutionMode %4 OriginUpperLeft
OpSource ESSL 310
OpName %4 "main"
%2 = OpTypeVoid
%3 = OpTypeFunction %2
%6 = OpTypeBool
%7 = OpConstantTrue %6
%4 = OpFunction %2 None %3
%5 = OpLabel
OpBranch %8
%8 = OpLabel
OpReturn
OpFunctionEnd
)";
const auto env = SPV_ENV_UNIVERSAL_1_4;
const auto consumer = nullptr;
const auto context = BuildModule(env, consumer, shader, kFuzzAssembleOption);
ASSERT_TRUE(IsValid(env, context.get()));
FactManager fact_manager;
// Id 4 is already in use
ASSERT_FALSE(TransformationAddDeadBlock(4, 5, true)
.IsApplicable(context.get(), fact_manager));
// Id 7 is not a block
ASSERT_FALSE(TransformationAddDeadBlock(100, 7, true)
.IsApplicable(context.get(), fact_manager));
TransformationAddDeadBlock transformation(100, 5, true);
ASSERT_TRUE(transformation.IsApplicable(context.get(), fact_manager));
transformation.Apply(context.get(), &fact_manager);
ASSERT_TRUE(IsValid(env, context.get()));
ASSERT_TRUE(fact_manager.BlockIsDead(100));
std::string after_transformation = R"(
OpCapability Shader
%1 = OpExtInstImport "GLSL.std.450"
OpMemoryModel Logical GLSL450
OpEntryPoint Fragment %4 "main"
OpExecutionMode %4 OriginUpperLeft
OpSource ESSL 310
OpName %4 "main"
%2 = OpTypeVoid
%3 = OpTypeFunction %2
%6 = OpTypeBool
%7 = OpConstantTrue %6
%4 = OpFunction %2 None %3
%5 = OpLabel
OpSelectionMerge %8 None
OpBranchConditional %7 %8 %100
%100 = OpLabel
OpBranch %8
%8 = OpLabel
OpReturn
OpFunctionEnd
)";
ASSERT_TRUE(IsEqual(env, after_transformation, context.get()));
}
TEST(TransformationAddDeadBlockTest, TargetBlockMustNotBeSelectionMerge) {
std::string shader = R"(
OpCapability Shader
%1 = OpExtInstImport "GLSL.std.450"
OpMemoryModel Logical GLSL450
OpEntryPoint Fragment %4 "main"
OpExecutionMode %4 OriginUpperLeft
OpSource ESSL 310
OpName %4 "main"
%2 = OpTypeVoid
%3 = OpTypeFunction %2
%6 = OpTypeBool
%7 = OpConstantTrue %6
%4 = OpFunction %2 None %3
%5 = OpLabel
OpSelectionMerge %10 None
OpBranchConditional %7 %8 %9
%8 = OpLabel
OpBranch %10
%9 = OpLabel
OpBranch %10
%10 = OpLabel
OpReturn
OpFunctionEnd
)";
const auto env = SPV_ENV_UNIVERSAL_1_4;
const auto consumer = nullptr;
const auto context = BuildModule(env, consumer, shader, kFuzzAssembleOption);
ASSERT_TRUE(IsValid(env, context.get()));
FactManager fact_manager;
ASSERT_FALSE(TransformationAddDeadBlock(100, 9, true)
.IsApplicable(context.get(), fact_manager));
}
TEST(TransformationAddDeadBlockTest, TargetBlockMustNotBeLoopMergeOrContinue) {
std::string shader = R"(
OpCapability Shader
%1 = OpExtInstImport "GLSL.std.450"
OpMemoryModel Logical GLSL450
OpEntryPoint Fragment %4 "main"
OpExecutionMode %4 OriginUpperLeft
OpSource ESSL 310
OpName %4 "main"
%2 = OpTypeVoid
%3 = OpTypeFunction %2
%6 = OpTypeBool
%7 = OpConstantTrue %6
%4 = OpFunction %2 None %3
%5 = OpLabel
OpBranch %8
%8 = OpLabel
OpLoopMerge %11 %12 None
OpBranchConditional %7 %9 %10
%9 = OpLabel
OpBranch %12
%10 = OpLabel
OpBranch %11
%12 = OpLabel
OpBranch %8
%11 = OpLabel
OpReturn
OpFunctionEnd
)";
const auto env = SPV_ENV_UNIVERSAL_1_4;
const auto consumer = nullptr;
const auto context = BuildModule(env, consumer, shader, kFuzzAssembleOption);
ASSERT_TRUE(IsValid(env, context.get()));
FactManager fact_manager;
// Bad because 9's successor is the loop continue target.
ASSERT_FALSE(TransformationAddDeadBlock(100, 9, true)
.IsApplicable(context.get(), fact_manager));
// Bad because 10's successor is the loop merge.
ASSERT_FALSE(TransformationAddDeadBlock(100, 10, true)
.IsApplicable(context.get(), fact_manager));
}
TEST(TransformationAddDeadBlockTest, SourceBlockMustNotBeLoopHead) {
std::string shader = R"(
OpCapability Shader
%1 = OpExtInstImport "GLSL.std.450"
OpMemoryModel Logical GLSL450
OpEntryPoint Fragment %4 "main"
OpExecutionMode %4 OriginUpperLeft
OpSource ESSL 310
OpName %4 "main"
%2 = OpTypeVoid
%3 = OpTypeFunction %2
%6 = OpTypeBool
%7 = OpConstantTrue %6
%4 = OpFunction %2 None %3
%5 = OpLabel
OpBranch %8
%8 = OpLabel
OpLoopMerge %11 %12 None
OpBranch %9
%9 = OpLabel
OpBranchConditional %7 %11 %12
%12 = OpLabel
OpBranch %8
%11 = OpLabel
OpReturn
OpFunctionEnd
)";
const auto env = SPV_ENV_UNIVERSAL_1_4;
const auto consumer = nullptr;
const auto context = BuildModule(env, consumer, shader, kFuzzAssembleOption);
ASSERT_TRUE(IsValid(env, context.get()));
FactManager fact_manager;
// Bad because 8 is a loop head.
ASSERT_FALSE(TransformationAddDeadBlock(100, 8, true)
.IsApplicable(context.get(), fact_manager));
}
TEST(TransformationAddDeadBlockTest, OpPhiInTarget) {
std::string shader = R"(
OpCapability Shader
%1 = OpExtInstImport "GLSL.std.450"
OpMemoryModel Logical GLSL450
OpEntryPoint Fragment %4 "main"
OpExecutionMode %4 OriginUpperLeft
OpSource ESSL 310
OpName %4 "main"
%2 = OpTypeVoid
%3 = OpTypeFunction %2
%6 = OpTypeBool
%7 = OpConstantTrue %6
%9 = OpTypeInt 32 0
%10 = OpConstant %9 1
%4 = OpFunction %2 None %3
%5 = OpLabel
OpBranch %8
%8 = OpLabel
%12 = OpPhi %6 %7 %5
%13 = OpPhi %9 %10 %5
OpReturn
OpFunctionEnd
)";
const auto env = SPV_ENV_UNIVERSAL_1_4;
const auto consumer = nullptr;
const auto context = BuildModule(env, consumer, shader, kFuzzAssembleOption);
ASSERT_TRUE(IsValid(env, context.get()));
FactManager fact_manager;
TransformationAddDeadBlock transformation(100, 5, true);
ASSERT_TRUE(transformation.IsApplicable(context.get(), fact_manager));
transformation.Apply(context.get(), &fact_manager);
ASSERT_TRUE(IsValid(env, context.get()));
ASSERT_TRUE(fact_manager.BlockIsDead(100));
std::string after_transformation = R"(
OpCapability Shader
%1 = OpExtInstImport "GLSL.std.450"
OpMemoryModel Logical GLSL450
OpEntryPoint Fragment %4 "main"
OpExecutionMode %4 OriginUpperLeft
OpSource ESSL 310
OpName %4 "main"
%2 = OpTypeVoid
%3 = OpTypeFunction %2
%6 = OpTypeBool
%7 = OpConstantTrue %6
%9 = OpTypeInt 32 0
%10 = OpConstant %9 1
%4 = OpFunction %2 None %3
%5 = OpLabel
OpSelectionMerge %8 None
OpBranchConditional %7 %8 %100
%100 = OpLabel
OpBranch %8
%8 = OpLabel
%12 = OpPhi %6 %7 %5 %7 %100
%13 = OpPhi %9 %10 %5 %10 %100
OpReturn
OpFunctionEnd
)";
ASSERT_TRUE(IsEqual(env, after_transformation, context.get()));
}
TEST(TransformationAddDeadBlockTest, BackEdge) {
std::string shader = R"(
OpCapability Shader
%1 = OpExtInstImport "GLSL.std.450"
OpMemoryModel Logical GLSL450
OpEntryPoint Fragment %4 "main"
OpExecutionMode %4 OriginUpperLeft
OpSource ESSL 310
OpName %4 "main"
%2 = OpTypeVoid
%3 = OpTypeFunction %2
%6 = OpTypeBool
%7 = OpConstantTrue %6
%4 = OpFunction %2 None %3
%5 = OpLabel
OpBranch %8
%8 = OpLabel
OpLoopMerge %10 %9 None
OpBranchConditional %7 %9 %10
%9 = OpLabel
OpBranch %8
%10 = OpLabel
OpReturn
OpFunctionEnd
)";
const auto env = SPV_ENV_UNIVERSAL_1_4;
const auto consumer = nullptr;
const auto context = BuildModule(env, consumer, shader, kFuzzAssembleOption);
ASSERT_TRUE(IsValid(env, context.get()));
FactManager fact_manager;
// 9 is a back edge block, so it would not be OK to add a dead block here,
// as then both 9 and the dead block would branch to the loop header, 8.
ASSERT_FALSE(TransformationAddDeadBlock(100, 9, true)
.IsApplicable(context.get(), fact_manager));
}
} // namespace
} // namespace fuzz
} // namespace spvtools