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https://github.com/KhronosGroup/SPIRV-Tools
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b8587c984a
This change allows the reducer to merge together blocks even when they are unreachable, but keeps the restriction of reachability in place for the optimizer. Fixes #4302.
90 lines
3.1 KiB
C++
90 lines
3.1 KiB
C++
// Copyright (c) 2019 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/transformation_merge_blocks.h"
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#include "source/fuzz/fuzzer_util.h"
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#include "source/opt/block_merge_util.h"
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namespace spvtools {
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namespace fuzz {
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TransformationMergeBlocks::TransformationMergeBlocks(
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protobufs::TransformationMergeBlocks message)
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: message_(std::move(message)) {}
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TransformationMergeBlocks::TransformationMergeBlocks(uint32_t block_id) {
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message_.set_block_id(block_id);
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}
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bool TransformationMergeBlocks::IsApplicable(
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opt::IRContext* ir_context, const TransformationContext& /*unused*/) const {
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auto second_block =
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fuzzerutil::MaybeFindBlock(ir_context, message_.block_id());
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// The given block must exist.
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if (!second_block) {
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return false;
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}
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// The block must have just one predecessor.
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auto predecessors = ir_context->cfg()->preds(second_block->id());
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if (predecessors.size() != 1) {
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return false;
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}
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auto first_block = ir_context->cfg()->block(predecessors.at(0));
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if (!ir_context->IsReachable(*first_block)) {
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return false;
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}
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return opt::blockmergeutil::CanMergeWithSuccessor(ir_context, first_block);
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}
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void TransformationMergeBlocks::Apply(opt::IRContext* ir_context,
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TransformationContext* /*unused*/) const {
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auto second_block =
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fuzzerutil::MaybeFindBlock(ir_context, message_.block_id());
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auto first_block = ir_context->cfg()->block(
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ir_context->cfg()->preds(second_block->id()).at(0));
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auto function = first_block->GetParent();
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// We need an iterator pointing to the predecessor, hence the loop.
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for (auto bi = function->begin(); bi != function->end(); ++bi) {
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if (bi->id() == first_block->id()) {
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assert(opt::blockmergeutil::CanMergeWithSuccessor(ir_context, &*bi) &&
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"Because 'Apply' should only be invoked if 'IsApplicable' holds, "
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"it must be possible to merge |bi| with its successor.");
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opt::blockmergeutil::MergeWithSuccessor(ir_context, function, bi);
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// Invalidate all analyses, since we have changed the module
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// significantly.
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ir_context->InvalidateAnalysesExceptFor(opt::IRContext::kAnalysisNone);
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return;
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}
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}
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assert(false &&
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"Control should not reach here - we should always find the desired "
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"block");
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}
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protobufs::Transformation TransformationMergeBlocks::ToMessage() const {
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protobufs::Transformation result;
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*result.mutable_merge_blocks() = message_;
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return result;
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}
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std::unordered_set<uint32_t> TransformationMergeBlocks::GetFreshIds() const {
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return std::unordered_set<uint32_t>();
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}
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} // namespace fuzz
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} // namespace spvtools
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