317 строки
14 KiB
C++
317 строки
14 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/shrinker.h"
|
|
|
|
#include <sstream>
|
|
|
|
#include "source/fuzz/added_function_reducer.h"
|
|
#include "source/fuzz/pseudo_random_generator.h"
|
|
#include "source/fuzz/replayer.h"
|
|
#include "source/opt/build_module.h"
|
|
#include "source/opt/ir_context.h"
|
|
#include "source/spirv_fuzzer_options.h"
|
|
#include "source/util/make_unique.h"
|
|
|
|
namespace spvtools {
|
|
namespace fuzz {
|
|
|
|
namespace {
|
|
|
|
// A helper to get the size of a protobuf transformation sequence in a less
|
|
// verbose manner.
|
|
uint32_t NumRemainingTransformations(
|
|
const protobufs::TransformationSequence& transformation_sequence) {
|
|
return static_cast<uint32_t>(transformation_sequence.transformation_size());
|
|
}
|
|
|
|
// A helper to return a transformation sequence identical to |transformations|,
|
|
// except that a chunk of size |chunk_size| starting from |chunk_index| x
|
|
// |chunk_size| is removed (or as many transformations as available if the whole
|
|
// chunk is not).
|
|
protobufs::TransformationSequence RemoveChunk(
|
|
const protobufs::TransformationSequence& transformations,
|
|
uint32_t chunk_index, uint32_t chunk_size) {
|
|
uint32_t lower = chunk_index * chunk_size;
|
|
uint32_t upper = std::min((chunk_index + 1) * chunk_size,
|
|
NumRemainingTransformations(transformations));
|
|
assert(lower < upper);
|
|
assert(upper <= NumRemainingTransformations(transformations));
|
|
protobufs::TransformationSequence result;
|
|
for (uint32_t j = 0; j < NumRemainingTransformations(transformations); j++) {
|
|
if (j >= lower && j < upper) {
|
|
continue;
|
|
}
|
|
protobufs::Transformation transformation =
|
|
transformations.transformation()[j];
|
|
*result.mutable_transformation()->Add() = transformation;
|
|
}
|
|
return result;
|
|
}
|
|
|
|
} // namespace
|
|
|
|
Shrinker::Shrinker(
|
|
spv_target_env target_env, MessageConsumer consumer,
|
|
const std::vector<uint32_t>& binary_in,
|
|
const protobufs::FactSequence& initial_facts,
|
|
const protobufs::TransformationSequence& transformation_sequence_in,
|
|
const InterestingnessFunction& interestingness_function,
|
|
uint32_t step_limit, bool validate_during_replay,
|
|
spv_validator_options validator_options)
|
|
: target_env_(target_env),
|
|
consumer_(std::move(consumer)),
|
|
binary_in_(binary_in),
|
|
initial_facts_(initial_facts),
|
|
transformation_sequence_in_(transformation_sequence_in),
|
|
interestingness_function_(interestingness_function),
|
|
step_limit_(step_limit),
|
|
validate_during_replay_(validate_during_replay),
|
|
validator_options_(validator_options) {}
|
|
|
|
Shrinker::~Shrinker() = default;
|
|
|
|
Shrinker::ShrinkerResult Shrinker::Run() {
|
|
// Check compatibility between the library version being linked with and the
|
|
// header files being used.
|
|
GOOGLE_PROTOBUF_VERIFY_VERSION;
|
|
|
|
SpirvTools tools(target_env_);
|
|
if (!tools.IsValid()) {
|
|
consumer_(SPV_MSG_ERROR, nullptr, {},
|
|
"Failed to create SPIRV-Tools interface; stopping.");
|
|
return {Shrinker::ShrinkerResultStatus::kFailedToCreateSpirvToolsInterface,
|
|
std::vector<uint32_t>(), protobufs::TransformationSequence()};
|
|
}
|
|
|
|
// Initial binary should be valid.
|
|
if (!tools.Validate(&binary_in_[0], binary_in_.size(), validator_options_)) {
|
|
consumer_(SPV_MSG_INFO, nullptr, {},
|
|
"Initial binary is invalid; stopping.");
|
|
return {Shrinker::ShrinkerResultStatus::kInitialBinaryInvalid,
|
|
std::vector<uint32_t>(), protobufs::TransformationSequence()};
|
|
}
|
|
|
|
// Run a replay of the initial transformation sequence to check that it
|
|
// succeeds.
|
|
auto initial_replay_result =
|
|
Replayer(target_env_, consumer_, binary_in_, initial_facts_,
|
|
transformation_sequence_in_,
|
|
static_cast<uint32_t>(
|
|
transformation_sequence_in_.transformation_size()),
|
|
validate_during_replay_, validator_options_)
|
|
.Run();
|
|
if (initial_replay_result.status !=
|
|
Replayer::ReplayerResultStatus::kComplete) {
|
|
return {ShrinkerResultStatus::kReplayFailed, std::vector<uint32_t>(),
|
|
protobufs::TransformationSequence()};
|
|
}
|
|
// Get the binary that results from running these transformations, and the
|
|
// subsequence of the initial transformations that actually apply (in
|
|
// principle this could be a strict subsequence).
|
|
std::vector<uint32_t> current_best_binary;
|
|
initial_replay_result.transformed_module->module()->ToBinary(
|
|
¤t_best_binary, false);
|
|
protobufs::TransformationSequence current_best_transformations =
|
|
std::move(initial_replay_result.applied_transformations);
|
|
|
|
// Check that the binary produced by applying the initial transformations is
|
|
// indeed interesting.
|
|
if (!interestingness_function_(current_best_binary, 0)) {
|
|
consumer_(SPV_MSG_INFO, nullptr, {},
|
|
"Initial binary is not interesting; stopping.");
|
|
return {ShrinkerResultStatus::kInitialBinaryNotInteresting,
|
|
std::vector<uint32_t>(), protobufs::TransformationSequence()};
|
|
}
|
|
|
|
uint32_t attempt = 0; // Keeps track of the number of shrink attempts that
|
|
// have been tried, whether successful or not.
|
|
|
|
uint32_t chunk_size =
|
|
std::max(1u, NumRemainingTransformations(current_best_transformations) /
|
|
2); // The number of contiguous transformations that the
|
|
// shrinker will try to remove in one go; starts
|
|
// high and decreases during the shrinking process.
|
|
|
|
// Keep shrinking until we:
|
|
// - reach the step limit,
|
|
// - run out of transformations to remove, or
|
|
// - cannot make the chunk size any smaller.
|
|
while (attempt < step_limit_ &&
|
|
!current_best_transformations.transformation().empty() &&
|
|
chunk_size > 0) {
|
|
bool progress_this_round =
|
|
false; // Used to decide whether to make the chunk size with which we
|
|
// remove transformations smaller. If we managed to remove at
|
|
// least one chunk of transformations at a particular chunk
|
|
// size, we set this flag so that we do not yet decrease the
|
|
// chunk size.
|
|
|
|
assert(chunk_size <=
|
|
NumRemainingTransformations(current_best_transformations) &&
|
|
"Chunk size should never exceed the number of transformations that "
|
|
"remain.");
|
|
|
|
// The number of chunks is the ceiling of (#remaining_transformations /
|
|
// chunk_size).
|
|
const uint32_t num_chunks =
|
|
(NumRemainingTransformations(current_best_transformations) +
|
|
chunk_size - 1) /
|
|
chunk_size;
|
|
assert(num_chunks >= 1 && "There should be at least one chunk.");
|
|
assert(num_chunks * chunk_size >=
|
|
NumRemainingTransformations(current_best_transformations) &&
|
|
"All transformations should be in some chunk.");
|
|
|
|
// We go through the transformations in reverse, in chunks of size
|
|
// |chunk_size|, using |chunk_index| to track which chunk to try removing
|
|
// next. The loop exits early if we reach the shrinking step limit.
|
|
for (int chunk_index = num_chunks - 1;
|
|
attempt < step_limit_ && chunk_index >= 0; chunk_index--) {
|
|
// Remove a chunk of transformations according to the current index and
|
|
// chunk size.
|
|
auto transformations_with_chunk_removed =
|
|
RemoveChunk(current_best_transformations,
|
|
static_cast<uint32_t>(chunk_index), chunk_size);
|
|
|
|
// Replay the smaller sequence of transformations to get a next binary and
|
|
// transformation sequence. Note that the transformations arising from
|
|
// replay might be even smaller than the transformations with the chunk
|
|
// removed, because removing those transformations might make further
|
|
// transformations inapplicable.
|
|
auto replay_result =
|
|
Replayer(
|
|
target_env_, consumer_, binary_in_, initial_facts_,
|
|
transformations_with_chunk_removed,
|
|
static_cast<uint32_t>(
|
|
transformations_with_chunk_removed.transformation_size()),
|
|
validate_during_replay_, validator_options_)
|
|
.Run();
|
|
if (replay_result.status != Replayer::ReplayerResultStatus::kComplete) {
|
|
// Replay should not fail; if it does, we need to abort shrinking.
|
|
return {ShrinkerResultStatus::kReplayFailed, std::vector<uint32_t>(),
|
|
protobufs::TransformationSequence()};
|
|
}
|
|
|
|
assert(
|
|
NumRemainingTransformations(replay_result.applied_transformations) >=
|
|
chunk_index * chunk_size &&
|
|
"Removing this chunk of transformations should not have an effect "
|
|
"on earlier chunks.");
|
|
|
|
std::vector<uint32_t> transformed_binary;
|
|
replay_result.transformed_module->module()->ToBinary(&transformed_binary,
|
|
false);
|
|
if (interestingness_function_(transformed_binary, attempt)) {
|
|
// If the binary arising from the smaller transformation sequence is
|
|
// interesting, this becomes our current best binary and transformation
|
|
// sequence.
|
|
current_best_binary = std::move(transformed_binary);
|
|
current_best_transformations =
|
|
std::move(replay_result.applied_transformations);
|
|
progress_this_round = true;
|
|
}
|
|
// Either way, this was a shrink attempt, so increment our count of shrink
|
|
// attempts.
|
|
attempt++;
|
|
}
|
|
if (!progress_this_round) {
|
|
// If we didn't manage to remove any chunks at this chunk size, try a
|
|
// smaller chunk size.
|
|
chunk_size /= 2;
|
|
}
|
|
// Decrease the chunk size until it becomes no larger than the number of
|
|
// remaining transformations.
|
|
while (chunk_size >
|
|
NumRemainingTransformations(current_best_transformations)) {
|
|
chunk_size /= 2;
|
|
}
|
|
}
|
|
|
|
// We now use spirv-reduce to minimise the functions associated with any
|
|
// AddFunction transformations that remain.
|
|
//
|
|
// Consider every remaining transformation.
|
|
for (uint32_t transformation_index = 0;
|
|
attempt < step_limit_ &&
|
|
transformation_index <
|
|
static_cast<uint32_t>(
|
|
current_best_transformations.transformation_size());
|
|
transformation_index++) {
|
|
// Skip all transformations apart from TransformationAddFunction.
|
|
if (!current_best_transformations.transformation(transformation_index)
|
|
.has_add_function()) {
|
|
continue;
|
|
}
|
|
// Invoke spirv-reduce on the function encoded in this AddFunction
|
|
// transformation. The details of this are rather involved, and so are
|
|
// encapsulated in a separate class.
|
|
auto added_function_reducer_result =
|
|
AddedFunctionReducer(target_env_, consumer_, binary_in_, initial_facts_,
|
|
current_best_transformations, transformation_index,
|
|
interestingness_function_, validate_during_replay_,
|
|
validator_options_, step_limit_, attempt)
|
|
.Run();
|
|
// Reducing the added function should succeed. If it doesn't, we report
|
|
// a shrinking error.
|
|
if (added_function_reducer_result.status !=
|
|
AddedFunctionReducer::AddedFunctionReducerResultStatus::kComplete) {
|
|
return {ShrinkerResultStatus::kAddedFunctionReductionFailed,
|
|
std::vector<uint32_t>(), protobufs::TransformationSequence()};
|
|
}
|
|
assert(current_best_transformations.transformation_size() ==
|
|
added_function_reducer_result.applied_transformations
|
|
.transformation_size() &&
|
|
"The number of transformations should not have changed.");
|
|
current_best_binary =
|
|
std::move(added_function_reducer_result.transformed_binary);
|
|
current_best_transformations =
|
|
std::move(added_function_reducer_result.applied_transformations);
|
|
// The added function reducer reports how many reduction attempts
|
|
// spirv-reduce took when reducing the function. We regard each of these
|
|
// as a shrinker attempt.
|
|
attempt += added_function_reducer_result.num_reduction_attempts;
|
|
}
|
|
|
|
// Indicate whether shrinking completed or was truncated due to reaching the
|
|
// step limit.
|
|
//
|
|
// Either way, the output from the shrinker is the best binary we saw, and the
|
|
// transformations that led to it.
|
|
assert(attempt <= step_limit_);
|
|
if (attempt == step_limit_) {
|
|
std::stringstream strstream;
|
|
strstream << "Shrinking did not complete; step limit " << step_limit_
|
|
<< " was reached.";
|
|
consumer_(SPV_MSG_WARNING, nullptr, {}, strstream.str().c_str());
|
|
return {Shrinker::ShrinkerResultStatus::kStepLimitReached,
|
|
std::move(current_best_binary),
|
|
std::move(current_best_transformations)};
|
|
}
|
|
return {Shrinker::ShrinkerResultStatus::kComplete,
|
|
std::move(current_best_binary),
|
|
std::move(current_best_transformations)};
|
|
}
|
|
|
|
uint32_t Shrinker::GetIdBound(const std::vector<uint32_t>& binary) const {
|
|
// Build the module from the input binary.
|
|
std::unique_ptr<opt::IRContext> ir_context =
|
|
BuildModule(target_env_, consumer_, binary.data(), binary.size());
|
|
assert(ir_context && "Error building module.");
|
|
return ir_context->module()->id_bound();
|
|
}
|
|
|
|
} // namespace fuzz
|
|
} // namespace spvtools
|