mirror of
https://github.com/KhronosGroup/SPIRV-Tools
synced 2024-11-23 04:00:05 +00:00
1b6fd37fa6
This change refactors the 'split blocks' transformation so that an instruction is identified via a base, opcode, and number of those opcodes to be skipped when searching from the base, as opposed to the previous design which used a base and offset.
107 lines
4.2 KiB
C++
107 lines
4.2 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_split_blocks.h"
|
|
|
|
#include <vector>
|
|
|
|
#include "source/fuzz/instruction_descriptor.h"
|
|
#include "source/fuzz/transformation_split_block.h"
|
|
|
|
namespace spvtools {
|
|
namespace fuzz {
|
|
|
|
FuzzerPassSplitBlocks::FuzzerPassSplitBlocks(
|
|
opt::IRContext* ir_context, FactManager* fact_manager,
|
|
FuzzerContext* fuzzer_context,
|
|
protobufs::TransformationSequence* transformations)
|
|
: FuzzerPass(ir_context, fact_manager, fuzzer_context, transformations) {}
|
|
|
|
FuzzerPassSplitBlocks::~FuzzerPassSplitBlocks() = default;
|
|
|
|
void FuzzerPassSplitBlocks::Apply() {
|
|
// Gather up pointers to all the blocks in the module. We are then able to
|
|
// iterate over these pointers and split the blocks to which they point;
|
|
// we cannot safely split blocks while we iterate through the module.
|
|
std::vector<opt::BasicBlock*> blocks;
|
|
for (auto& function : *GetIRContext()->module()) {
|
|
for (auto& block : function) {
|
|
blocks.push_back(&block);
|
|
}
|
|
}
|
|
|
|
// Now go through all the block pointers that were gathered.
|
|
for (auto& block : blocks) {
|
|
// Probabilistically decide whether to try to split this block.
|
|
if (!GetFuzzerContext()->ChoosePercentage(
|
|
GetFuzzerContext()->GetChanceOfSplittingBlock())) {
|
|
// We are not going to try to split this block.
|
|
continue;
|
|
}
|
|
|
|
// TODO(https://github.com/KhronosGroup/SPIRV-Tools/issues/2964): consider
|
|
// taking a simpler approach to identifying the instruction before which
|
|
// to split a block.
|
|
|
|
// We are going to try to split this block. We now need to choose where
|
|
// to split it. We describe the instruction before which we would like to
|
|
// split a block via an InstructionDescriptor, details of which are
|
|
// commented in the protobufs definition file.
|
|
std::vector<protobufs::InstructionDescriptor> instruction_descriptors;
|
|
|
|
// The initial base instruction is the block label.
|
|
uint32_t base = block->id();
|
|
|
|
// Counts the number of times we have seen each opcode since we reset the
|
|
// base instruction.
|
|
std::map<SpvOp, uint32_t> skip_count;
|
|
|
|
// Consider every instruction in the block. The label is excluded: it is
|
|
// only necessary to consider it as a base in case the first instruction
|
|
// in the block does not have a result id.
|
|
for (auto& inst : *block) {
|
|
if (inst.HasResultId()) {
|
|
// In the case that the instruction has a result id, we use the
|
|
// instruction as its own base, and clear the skip counts we have
|
|
// collected.
|
|
base = inst.result_id();
|
|
skip_count.clear();
|
|
}
|
|
const SpvOp opcode = inst.opcode();
|
|
instruction_descriptors.emplace_back(MakeInstructionDescriptor(
|
|
base, opcode, skip_count.count(opcode) ? skip_count.at(opcode) : 0));
|
|
if (!inst.HasResultId()) {
|
|
skip_count[opcode] =
|
|
skip_count.count(opcode) ? skip_count.at(opcode) + 1 : 1;
|
|
}
|
|
}
|
|
// Having identified all the places we might be able to split the block,
|
|
// we choose one of them.
|
|
auto transformation = TransformationSplitBlock(
|
|
instruction_descriptors[GetFuzzerContext()->RandomIndex(
|
|
instruction_descriptors)],
|
|
GetFuzzerContext()->GetFreshId());
|
|
// If the position we have chosen turns out to be a valid place to split
|
|
// the block, we apply the split. Otherwise the block just doesn't get
|
|
// split.
|
|
if (transformation.IsApplicable(GetIRContext(), *GetFactManager())) {
|
|
transformation.Apply(GetIRContext(), GetFactManager());
|
|
*GetTransformations()->add_transformation() = transformation.ToMessage();
|
|
}
|
|
}
|
|
}
|
|
|
|
} // namespace fuzz
|
|
} // namespace spvtools
|