mirror of
https://github.com/KhronosGroup/SPIRV-Tools
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95 lines
3.8 KiB
C++
95 lines
3.8 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/fuzzer_pass_add_dead_continues.h"
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#include "source/fuzz/fuzzer_util.h"
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#include "source/fuzz/transformation_add_dead_continue.h"
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#include "source/opt/ir_context.h"
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namespace spvtools {
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namespace fuzz {
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FuzzerPassAddDeadContinues::FuzzerPassAddDeadContinues(
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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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FuzzerPassAddDeadContinues::~FuzzerPassAddDeadContinues() = default;
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void FuzzerPassAddDeadContinues::Apply() {
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// Consider every block in every function.
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for (auto& function : *GetIRContext()->module()) {
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for (auto& block : function) {
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// Get the label id of the continue target of the innermost loop.
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auto continue_block_id =
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block.IsLoopHeader()
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? block.ContinueBlockId()
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: GetIRContext()->GetStructuredCFGAnalysis()->LoopContinueBlock(
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block.id());
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// This transformation is not applicable if current block is not inside a
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// loop.
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if (continue_block_id == 0) {
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continue;
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}
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auto* continue_block =
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fuzzerutil::MaybeFindBlock(GetIRContext(), continue_block_id);
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assert(continue_block && "Continue block is null");
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// Analyze return type of each OpPhi instruction in the continue target
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// and provide an id for the transformation if needed.
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std::vector<uint32_t> phi_ids;
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// Check whether current block has an edge to the continue target.
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// If this is the case, we don't need to do anything.
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if (!block.IsSuccessor(continue_block)) {
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continue_block->ForEachPhiInst([this, &phi_ids](opt::Instruction* phi) {
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// Add an additional operand for OpPhi instruction. Use a constant
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// if possible, and an undef otherwise.
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if (fuzzerutil::CanCreateConstant(GetIRContext(), phi->type_id())) {
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// We mark the constant as irrelevant so that we can replace it with
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// a more interesting value later.
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phi_ids.push_back(FindOrCreateZeroConstant(phi->type_id(), true));
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} else {
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phi_ids.push_back(FindOrCreateGlobalUndef(phi->type_id()));
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}
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});
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}
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// Make sure the module contains a boolean constant equal to
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// |condition_value|.
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bool condition_value = GetFuzzerContext()->ChooseEven();
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FindOrCreateBoolConstant(condition_value, false);
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// Make a transformation to add a dead continue from this node; if the
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// node turns out to be inappropriate (e.g. by not being in a loop) the
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// precondition for the transformation will fail and it will be ignored.
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auto candidate_transformation = TransformationAddDeadContinue(
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block.id(), condition_value, std::move(phi_ids));
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// Probabilistically decide whether to apply the transformation in the
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// case that it is applicable.
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if (GetFuzzerContext()->ChoosePercentage(
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GetFuzzerContext()->GetChanceOfAddingDeadContinue())) {
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MaybeApplyTransformation(candidate_transformation);
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}
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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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