SPIRV-Tools/source/fuzz/fuzzer_pass_add_bit_instruction_synonyms.cpp
Alastair Donaldson 9c4481419e
spirv-fuzz: Allow inapplicable transformations to be ignored (#4407)
spirv-fuzz features transformations that should be applicable by
construction. Assertions are used to detect when such transformations
turn out to be inapplicable. Failures of such assertions indicate bugs
in the fuzzer. However, when using the fuzzer at scale (e.g. in
ClusterFuzz) reports of these assertion failures create noise, and
cause the fuzzer to exit early. This change adds an option whereby
inapplicable transformations can be ignored. This reduces noise and
allows fuzzing to continue even when a transformation that should be
applicable but is not has been erroneously created.
2021-07-28 22:59:37 +01:00

80 lines
3.1 KiB
C++

// Copyright (c) 2020 André Perez Maselco
//
// 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_add_bit_instruction_synonyms.h"
#include "source/fuzz/fuzzer_util.h"
#include "source/fuzz/instruction_descriptor.h"
#include "source/fuzz/transformation_add_bit_instruction_synonym.h"
namespace spvtools {
namespace fuzz {
FuzzerPassAddBitInstructionSynonyms::FuzzerPassAddBitInstructionSynonyms(
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 FuzzerPassAddBitInstructionSynonyms::Apply() {
for (auto& function : *GetIRContext()->module()) {
for (auto& block : function) {
for (auto& instruction : block) {
// This fuzzer pass can add a *lot* of ids. We bail out early if we hit
// the recommended id limit.
if (GetIRContext()->module()->id_bound() >=
GetFuzzerContext()->GetIdBoundLimit()) {
return;
}
// Randomly decides whether the transformation will be applied.
if (!GetFuzzerContext()->ChoosePercentage(
GetFuzzerContext()->GetChanceOfAddingBitInstructionSynonym())) {
continue;
}
// Make sure fuzzer never applies a transformation to a bitwise
// instruction with differently signed operands, only integer operands
// are supported and bitwise operations are supported only.
if (!TransformationAddBitInstructionSynonym::IsInstructionSupported(
GetIRContext(), &instruction)) {
continue;
}
// Make sure all bit indexes are defined as 32-bit unsigned integers.
uint32_t width = GetIRContext()
->get_type_mgr()
->GetType(instruction.type_id())
->AsInteger()
->width();
for (uint32_t i = 0; i < width; i++) {
FindOrCreateIntegerConstant({i}, 32, false, false);
}
// Applies the add bit instruction synonym transformation.
ApplyTransformation(TransformationAddBitInstructionSynonym(
instruction.result_id(),
GetFuzzerContext()->GetFreshIds(
TransformationAddBitInstructionSynonym::GetRequiredFreshIdCount(
GetIRContext(), &instruction))));
}
}
}
}
} // namespace fuzz
} // namespace spvtools