SPIRV-Tools/source/fuzz/fuzzer_pass_copy_objects.cpp
Alastair Donaldson 5910bb8e94
spirv-fuzz: add transformation and pass to construct composites (#2941)
Adds a fuzzer pass and transformation to create a composite (array,
matrix, struct or vector) from available constituent components, and
inform the fact manager that each component of the new composite is
synonymous with the id that was used to construct it. This allows the
"replace id with synonym" pass to then replace uses of said ids with
uses of elements extracted from the composite.

Fixes #2858.
2019-10-08 14:04:10 +01:00

76 lines
3.0 KiB
C++

// 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_copy_objects.h"
#include "source/fuzz/fuzzer_util.h"
#include "source/fuzz/transformation_copy_object.h"
namespace spvtools {
namespace fuzz {
FuzzerPassCopyObjects::FuzzerPassCopyObjects(
opt::IRContext* ir_context, FactManager* fact_manager,
FuzzerContext* fuzzer_context,
protobufs::TransformationSequence* transformations)
: FuzzerPass(ir_context, fact_manager, fuzzer_context, transformations) {}
FuzzerPassCopyObjects::~FuzzerPassCopyObjects() = default;
void FuzzerPassCopyObjects::Apply() {
MaybeAddTransformationBeforeEachInstruction(
[this](const opt::Function& function, opt::BasicBlock* block,
opt::BasicBlock::iterator inst_it, uint32_t base,
uint32_t offset) -> uint32_t {
// Check whether it is legitimate to insert a copy before this
// instruction.
if (!fuzzerutil::CanInsertOpcodeBeforeInstruction(SpvOpCopyObject,
inst_it)) {
return 0;
}
// Randomly decide whether to try inserting an object copy here.
if (!GetFuzzerContext()->ChoosePercentage(
GetFuzzerContext()->GetChanceOfCopyingObject())) {
return 0;
}
std::vector<opt::Instruction*> relevant_instructions =
FindAvailableInstructions(function, block, inst_it,
fuzzerutil::CanMakeSynonymOf);
// At this point, |relevant_instructions| contains all the instructions
// we might think of copying.
if (relevant_instructions.empty()) {
return 0;
}
// Choose a copyable instruction at random, and create and apply an
// object copying transformation based on it.
uint32_t index = GetFuzzerContext()->RandomIndex(relevant_instructions);
TransformationCopyObject transformation(
relevant_instructions[index]->result_id(), base, offset,
GetFuzzerContext()->GetFreshId());
assert(transformation.IsApplicable(GetIRContext(), *GetFactManager()) &&
"This transformation should be applicable by construction.");
transformation.Apply(GetIRContext(), GetFactManager());
*GetTransformations()->add_transformation() =
transformation.ToMessage();
return 1;
});
}
} // namespace fuzz
} // namespace spvtools