SPIRV-Tools/source/fuzz/fuzzer_pass_merge_blocks.cpp
Alastair Donaldson 96354f5047
spirv-fuzz: Fuzzer pass to merge blocks (#3097)
This change adds a transformation and associated fuzzer pass for
merging adjacent blocks in a module, re-using block merging code from
the optimizer.
2019-12-12 15:27:40 +00:00

66 lines
2.5 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/fuzzer_pass_merge_blocks.h"
#include <vector>
#include "source/fuzz/transformation_merge_blocks.h"
namespace spvtools {
namespace fuzz {
FuzzerPassMergeBlocks::FuzzerPassMergeBlocks(
opt::IRContext* ir_context, FactManager* fact_manager,
FuzzerContext* fuzzer_context,
protobufs::TransformationSequence* transformations)
: FuzzerPass(ir_context, fact_manager, fuzzer_context, transformations) {}
FuzzerPassMergeBlocks::~FuzzerPassMergeBlocks() = default;
void FuzzerPassMergeBlocks::Apply() {
// First we populate a sequence of transformations that we might consider
// applying.
std::vector<TransformationMergeBlocks> potential_transformations;
// We do this by considering every block of every function.
for (auto& function : *GetIRContext()->module()) {
for (auto& block : function) {
// We probabilistically decide to ignore some blocks.
if (!GetFuzzerContext()->ChoosePercentage(
GetFuzzerContext()->GetChanceOfMergingBlocks())) {
continue;
}
// For other blocks, we add a transformation to merge the block into its
// predecessor if that transformation would be applicable.
TransformationMergeBlocks transformation(block.id());
if (transformation.IsApplicable(GetIRContext(), *GetFactManager())) {
potential_transformations.push_back(transformation);
}
}
}
while (!potential_transformations.empty()) {
uint32_t index = GetFuzzerContext()->RandomIndex(potential_transformations);
auto transformation = potential_transformations.at(index);
potential_transformations.erase(potential_transformations.begin() + index);
if (transformation.IsApplicable(GetIRContext(), *GetFactManager())) {
transformation.Apply(GetIRContext(), GetFactManager());
*GetTransformations()->add_transformation() = transformation.ToMessage();
}
}
}
} // namespace fuzz
} // namespace spvtools