139 строки
5.1 KiB
C++
139 строки
5.1 KiB
C++
// Copyright (c) 2020 Vasyl Teliman
|
|
//
|
|
// 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_wrap_regions_in_selections.h"
|
|
|
|
#include "source/fuzz/fuzzer_context.h"
|
|
#include "source/fuzz/instruction_descriptor.h"
|
|
#include "source/fuzz/transformation_split_block.h"
|
|
#include "source/fuzz/transformation_wrap_region_in_selection.h"
|
|
|
|
namespace spvtools {
|
|
namespace fuzz {
|
|
|
|
FuzzerPassWrapRegionsInSelections::FuzzerPassWrapRegionsInSelections(
|
|
opt::IRContext* ir_context, TransformationContext* transformation_context,
|
|
FuzzerContext* fuzzer_context,
|
|
protobufs::TransformationSequence* transformations,
|
|
bool ignore_inapplicable_transformations)
|
|
: FuzzerPass(ir_context, transformation_context, fuzzer_context,
|
|
transformations, ignore_inapplicable_transformations) {}
|
|
|
|
void FuzzerPassWrapRegionsInSelections::Apply() {
|
|
for (auto& function : *GetIRContext()->module()) {
|
|
if (!GetFuzzerContext()->ChoosePercentage(
|
|
GetFuzzerContext()->GetChanceOfWrappingRegionInSelection())) {
|
|
continue;
|
|
}
|
|
|
|
// It is easier to select an element at random from a vector than from an
|
|
// instruction list.
|
|
std::vector<opt::BasicBlock*> header_block_candidates;
|
|
for (auto& block : function) {
|
|
header_block_candidates.push_back(&block);
|
|
}
|
|
|
|
if (header_block_candidates.empty()) {
|
|
continue;
|
|
}
|
|
|
|
// Try to get a header block candidate that will increase the chances of the
|
|
// transformation being applicable.
|
|
auto* header_block_candidate = MaybeGetHeaderBlockCandidate(
|
|
header_block_candidates[GetFuzzerContext()->RandomIndex(
|
|
header_block_candidates)]);
|
|
if (!header_block_candidate) {
|
|
continue;
|
|
}
|
|
|
|
std::vector<opt::BasicBlock*> merge_block_candidates;
|
|
for (auto& block : function) {
|
|
if (GetIRContext()->GetDominatorAnalysis(&function)->StrictlyDominates(
|
|
header_block_candidate, &block) &&
|
|
GetIRContext()
|
|
->GetPostDominatorAnalysis(&function)
|
|
->StrictlyDominates(&block, header_block_candidate)) {
|
|
merge_block_candidates.push_back(&block);
|
|
}
|
|
}
|
|
|
|
if (merge_block_candidates.empty()) {
|
|
continue;
|
|
}
|
|
|
|
// Try to get a merge block candidate that will increase the chances of the
|
|
// transformation being applicable.
|
|
auto* merge_block_candidate = MaybeGetMergeBlockCandidate(
|
|
merge_block_candidates[GetFuzzerContext()->RandomIndex(
|
|
merge_block_candidates)]);
|
|
if (!merge_block_candidate) {
|
|
continue;
|
|
}
|
|
|
|
if (!TransformationWrapRegionInSelection::IsApplicableToBlockRange(
|
|
GetIRContext(), header_block_candidate->id(),
|
|
merge_block_candidate->id())) {
|
|
continue;
|
|
}
|
|
|
|
// This boolean constant will be used as a condition for the
|
|
// OpBranchConditional instruction. We mark it as irrelevant to be able to
|
|
// replace it with a more interesting value later.
|
|
auto branch_condition = GetFuzzerContext()->ChooseEven();
|
|
FindOrCreateBoolConstant(branch_condition, true);
|
|
|
|
ApplyTransformation(TransformationWrapRegionInSelection(
|
|
header_block_candidate->id(), merge_block_candidate->id(),
|
|
branch_condition));
|
|
}
|
|
}
|
|
|
|
opt::BasicBlock*
|
|
FuzzerPassWrapRegionsInSelections::MaybeGetHeaderBlockCandidate(
|
|
opt::BasicBlock* header_block_candidate) {
|
|
// Try to create a preheader if |header_block_candidate| is a loop header.
|
|
if (header_block_candidate->IsLoopHeader()) {
|
|
// GetOrCreateSimpleLoopPreheader only supports reachable blocks.
|
|
return GetIRContext()->cfg()->preds(header_block_candidate->id()).size() ==
|
|
1
|
|
? nullptr
|
|
: GetOrCreateSimpleLoopPreheader(header_block_candidate->id());
|
|
}
|
|
|
|
// Try to split |header_block_candidate| if it's already a header block.
|
|
if (header_block_candidate->GetMergeInst()) {
|
|
SplitBlockAfterOpPhiOrOpVariable(header_block_candidate->id());
|
|
}
|
|
|
|
return header_block_candidate;
|
|
}
|
|
|
|
opt::BasicBlock* FuzzerPassWrapRegionsInSelections::MaybeGetMergeBlockCandidate(
|
|
opt::BasicBlock* merge_block_candidate) {
|
|
// If |merge_block_candidate| is a merge block of some construct, try to split
|
|
// it and return a newly created block.
|
|
if (GetIRContext()->GetStructuredCFGAnalysis()->IsMergeBlock(
|
|
merge_block_candidate->id())) {
|
|
// We can't split a merge block if it's also a loop header.
|
|
return merge_block_candidate->IsLoopHeader()
|
|
? nullptr
|
|
: SplitBlockAfterOpPhiOrOpVariable(merge_block_candidate->id());
|
|
}
|
|
|
|
return merge_block_candidate;
|
|
}
|
|
|
|
} // namespace fuzz
|
|
} // namespace spvtools
|