| // 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_apply_id_synonyms.h" |
| |
| #include "source/fuzz/data_descriptor.h" |
| #include "source/fuzz/fuzzer_util.h" |
| #include "source/fuzz/id_use_descriptor.h" |
| #include "source/fuzz/instruction_descriptor.h" |
| #include "source/fuzz/transformation_composite_extract.h" |
| #include "source/fuzz/transformation_replace_id_with_synonym.h" |
| |
| namespace spvtools { |
| namespace fuzz { |
| |
| FuzzerPassApplyIdSynonyms::FuzzerPassApplyIdSynonyms( |
| opt::IRContext* ir_context, FactManager* fact_manager, |
| FuzzerContext* fuzzer_context, |
| protobufs::TransformationSequence* transformations) |
| : FuzzerPass(ir_context, fact_manager, fuzzer_context, transformations) {} |
| |
| FuzzerPassApplyIdSynonyms::~FuzzerPassApplyIdSynonyms() = default; |
| |
| void FuzzerPassApplyIdSynonyms::Apply() { |
| for (auto id_with_known_synonyms : |
| GetFactManager()->GetIdsForWhichSynonymsAreKnown(GetIRContext())) { |
| // Gather up all uses of |id_with_known_synonym|, and then subsequently |
| // iterate over these uses. We use this separation because, when |
| // considering a given use, we might apply a transformation that will |
| // invalidate the def-use manager. |
| std::vector<std::pair<opt::Instruction*, uint32_t>> uses; |
| GetIRContext()->get_def_use_mgr()->ForEachUse( |
| id_with_known_synonyms, |
| [&uses](opt::Instruction* use_inst, uint32_t use_index) -> void { |
| uses.emplace_back( |
| std::pair<opt::Instruction*, uint32_t>(use_inst, use_index)); |
| }); |
| |
| for (auto& use : uses) { |
| auto use_inst = use.first; |
| auto use_index = use.second; |
| auto block_containing_use = GetIRContext()->get_instr_block(use_inst); |
| // The use might not be in a block; e.g. it could be a decoration. |
| if (!block_containing_use) { |
| continue; |
| } |
| if (!GetFuzzerContext()->ChoosePercentage( |
| GetFuzzerContext()->GetChanceOfReplacingIdWithSynonym())) { |
| continue; |
| } |
| // |use_index| is the absolute index of the operand. We require |
| // the index of the operand restricted to input operands only, so |
| // we subtract the number of non-input operands from |use_index|. |
| uint32_t use_in_operand_index = |
| use_index - use_inst->NumOperands() + use_inst->NumInOperands(); |
| if (!TransformationReplaceIdWithSynonym::UseCanBeReplacedWithSynonym( |
| GetIRContext(), use_inst, use_in_operand_index)) { |
| continue; |
| } |
| |
| std::vector<const protobufs::DataDescriptor*> synonyms_to_try; |
| for (auto& data_descriptor : GetFactManager()->GetSynonymsForId( |
| id_with_known_synonyms, GetIRContext())) { |
| protobufs::DataDescriptor descriptor_for_this_id = |
| MakeDataDescriptor(id_with_known_synonyms, {}); |
| if (DataDescriptorEquals()(data_descriptor, &descriptor_for_this_id)) { |
| // Exclude the fact that the id is synonymous with itself. |
| continue; |
| } |
| synonyms_to_try.push_back(data_descriptor); |
| } |
| while (!synonyms_to_try.empty()) { |
| auto synonym_index = GetFuzzerContext()->RandomIndex(synonyms_to_try); |
| auto synonym_to_try = synonyms_to_try[synonym_index]; |
| synonyms_to_try.erase(synonyms_to_try.begin() + synonym_index); |
| |
| if (synonym_to_try->index_size() > 0 && |
| use_inst->opcode() == SpvOpPhi) { |
| // We are trying to replace an operand to an OpPhi. This means |
| // we cannot use a composite synonym, because that requires |
| // extracting a component from a composite and we cannot insert |
| // an extract instruction before an OpPhi. |
| // |
| // TODO(afd): We could consider inserting the extract instruction |
| // into the relevant parent block of the OpPhi. |
| continue; |
| } |
| |
| if (!TransformationReplaceIdWithSynonym::IdsIsAvailableAtUse( |
| GetIRContext(), use_inst, use_in_operand_index, |
| synonym_to_try->object())) { |
| continue; |
| } |
| |
| // We either replace the use with an id known to be synonymous, or |
| // an id that will hold the result of extracting a synonym from a |
| // composite. |
| uint32_t id_with_which_to_replace_use; |
| if (synonym_to_try->index_size() == 0) { |
| id_with_which_to_replace_use = synonym_to_try->object(); |
| } else { |
| id_with_which_to_replace_use = GetFuzzerContext()->GetFreshId(); |
| protobufs::InstructionDescriptor instruction_to_insert_before = |
| MakeInstructionDescriptor(GetIRContext(), use_inst); |
| TransformationCompositeExtract composite_extract_transformation( |
| instruction_to_insert_before, id_with_which_to_replace_use, |
| synonym_to_try->object(), |
| fuzzerutil::RepeatedFieldToVector(synonym_to_try->index())); |
| assert(composite_extract_transformation.IsApplicable( |
| GetIRContext(), *GetFactManager()) && |
| "Transformation should be applicable by construction."); |
| composite_extract_transformation.Apply(GetIRContext(), |
| GetFactManager()); |
| *GetTransformations()->add_transformation() = |
| composite_extract_transformation.ToMessage(); |
| } |
| |
| TransformationReplaceIdWithSynonym replace_id_transformation( |
| MakeIdUseDescriptorFromUse(GetIRContext(), use_inst, |
| use_in_operand_index), |
| id_with_which_to_replace_use); |
| |
| // The transformation should be applicable by construction. |
| assert(replace_id_transformation.IsApplicable(GetIRContext(), |
| *GetFactManager())); |
| replace_id_transformation.Apply(GetIRContext(), GetFactManager()); |
| *GetTransformations()->add_transformation() = |
| replace_id_transformation.ToMessage(); |
| break; |
| } |
| } |
| } |
| } |
| |
| } // namespace fuzz |
| } // namespace spvtools |