mirror of
https://github.com/KhronosGroup/SPIRV-Tools
synced 2024-10-18 11:10:05 +00:00
9c4481419e
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.
79 lines
2.9 KiB
C++
79 lines
2.9 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_permute_blocks.h"
|
|
|
|
#include "source/fuzz/transformation_move_block_down.h"
|
|
|
|
namespace spvtools {
|
|
namespace fuzz {
|
|
|
|
FuzzerPassPermuteBlocks::FuzzerPassPermuteBlocks(
|
|
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 FuzzerPassPermuteBlocks::Apply() {
|
|
// For now we do something very simple: we randomly decide whether to move a
|
|
// block, and for each block that we do move, we push it down as far as we
|
|
// legally can.
|
|
// TODO(https://github.com/KhronosGroup/SPIRV-Tools/issues/2635): it would be
|
|
// nice to randomly sample from the set of legal block permutations and then
|
|
// encode the chosen permutation via a series of move-block-down
|
|
// transformations. This should be possible but will require some thought.
|
|
|
|
for (auto& function : *GetIRContext()->module()) {
|
|
std::vector<uint32_t> block_ids;
|
|
// Collect all block ids for the function before messing with block
|
|
// ordering.
|
|
for (auto& block : function) {
|
|
block_ids.push_back(block.id());
|
|
}
|
|
// Now consider each block id. We consider block ids in reverse, because
|
|
// e.g. in code generated from the following:
|
|
//
|
|
// if (...) {
|
|
// A
|
|
// B
|
|
// } else {
|
|
// C
|
|
// }
|
|
//
|
|
// block A cannot be moved down, but B has freedom to move and that movement
|
|
// would provide more freedom for A to move.
|
|
for (auto id = block_ids.rbegin(); id != block_ids.rend(); ++id) {
|
|
// Randomly decide whether to ignore the block id.
|
|
if (!GetFuzzerContext()->ChoosePercentage(
|
|
GetFuzzerContext()->GetChanceOfMovingBlockDown())) {
|
|
continue;
|
|
}
|
|
// Keep pushing the block down, until pushing down fails.
|
|
// The loop is guaranteed to terminate because a block cannot be pushed
|
|
// down indefinitely.
|
|
while (true) {
|
|
TransformationMoveBlockDown transformation(*id);
|
|
if (!MaybeApplyTransformation(transformation)) {
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
} // namespace fuzz
|
|
} // namespace spvtools
|