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https://github.com/KhronosGroup/SPIRV-Tools
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eade36db22
This PR introduces FuzzerPassAddLoopPreheaders, which: - Finds existing loop headers - If they have no simple preheader (where simple means that the preheader itself is not a loop header), randomly decides whether to add one. Fixes #3621.
67 lines
2.2 KiB
C++
67 lines
2.2 KiB
C++
// Copyright (c) 2020 Google LLC
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "source/fuzz/fuzzer_pass_add_loop_preheaders.h"
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#include "source/fuzz/fuzzer_util.h"
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#include "source/fuzz/transformation_add_loop_preheader.h"
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namespace spvtools {
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namespace fuzz {
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FuzzerPassAddLoopPreheaders::FuzzerPassAddLoopPreheaders(
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opt::IRContext* ir_context, TransformationContext* transformation_context,
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FuzzerContext* fuzzer_context,
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protobufs::TransformationSequence* transformations)
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: FuzzerPass(ir_context, transformation_context, fuzzer_context,
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transformations) {}
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FuzzerPassAddLoopPreheaders::~FuzzerPassAddLoopPreheaders() = default;
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void FuzzerPassAddLoopPreheaders::Apply() {
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for (auto& function : *GetIRContext()->module()) {
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// Keep track of all the loop headers we want to add a preheader to.
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std::vector<uint32_t> loop_header_ids_to_consider;
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for (auto& block : function) {
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// We only care about loop headers.
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if (!block.IsLoopHeader()) {
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continue;
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}
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// Randomly decide whether to consider this header.
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if (!GetFuzzerContext()->ChoosePercentage(
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GetFuzzerContext()->GetChanceOfAddingLoopPreheader())) {
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continue;
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}
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// We exclude loop headers with just one predecessor (the back-edge block)
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// because they are unreachable.
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if (GetIRContext()->cfg()->preds(block.id()).size() < 2) {
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continue;
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}
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loop_header_ids_to_consider.push_back(block.id());
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}
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for (uint32_t header_id : loop_header_ids_to_consider) {
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// If not already present, add a preheader which is not also a loop
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// header.
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GetOrCreateSimpleLoopPreheader(header_id);
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}
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}
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}
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} // namespace fuzz
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} // namespace spvtools
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