SPIRV-Tools/source/fuzz/transformation_merge_blocks.cpp
Alastair Donaldson fcb22ecf0f
spirv-fuzz: Report fresh ids in transformations (#3856)
Adds a virtual method, GetFreshIds(), to Transformation. Every
transformation uses this to indicate which ids in its protobuf message
are fresh ids. This means that when replaying a sequence of
transformations the replayer can obtain a smallest id that is not in
use by the module already and that will not be used by any
transformation by necessity. Ids greater than or equal to this id
can be used as overflow ids.

Fixes #3851.
2020-09-29 22:12:49 +01:00

87 lines
3.1 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/transformation_merge_blocks.h"
#include "source/fuzz/fuzzer_util.h"
#include "source/opt/block_merge_util.h"
namespace spvtools {
namespace fuzz {
TransformationMergeBlocks::TransformationMergeBlocks(
const spvtools::fuzz::protobufs::TransformationMergeBlocks& message)
: message_(message) {}
TransformationMergeBlocks::TransformationMergeBlocks(uint32_t block_id) {
message_.set_block_id(block_id);
}
bool TransformationMergeBlocks::IsApplicable(
opt::IRContext* ir_context, const TransformationContext& /*unused*/) const {
auto second_block =
fuzzerutil::MaybeFindBlock(ir_context, message_.block_id());
// The given block must exist.
if (!second_block) {
return false;
}
// The block must have just one predecessor.
auto predecessors = ir_context->cfg()->preds(second_block->id());
if (predecessors.size() != 1) {
return false;
}
auto first_block = ir_context->cfg()->block(predecessors.at(0));
return opt::blockmergeutil::CanMergeWithSuccessor(ir_context, first_block);
}
void TransformationMergeBlocks::Apply(opt::IRContext* ir_context,
TransformationContext* /*unused*/) const {
auto second_block =
fuzzerutil::MaybeFindBlock(ir_context, message_.block_id());
auto first_block = ir_context->cfg()->block(
ir_context->cfg()->preds(second_block->id()).at(0));
auto function = first_block->GetParent();
// We need an iterator pointing to the predecessor, hence the loop.
for (auto bi = function->begin(); bi != function->end(); ++bi) {
if (bi->id() == first_block->id()) {
assert(opt::blockmergeutil::CanMergeWithSuccessor(ir_context, &*bi) &&
"Because 'Apply' should only be invoked if 'IsApplicable' holds, "
"it must be possible to merge |bi| with its successor.");
opt::blockmergeutil::MergeWithSuccessor(ir_context, function, bi);
// Invalidate all analyses, since we have changed the module
// significantly.
ir_context->InvalidateAnalysesExceptFor(opt::IRContext::kAnalysisNone);
return;
}
}
assert(false &&
"Control should not reach here - we should always find the desired "
"block");
}
protobufs::Transformation TransformationMergeBlocks::ToMessage() const {
protobufs::Transformation result;
*result.mutable_merge_blocks() = message_;
return result;
}
std::unordered_set<uint32_t> TransformationMergeBlocks::GetFreshIds() const {
return std::unordered_set<uint32_t>();
}
} // namespace fuzz
} // namespace spvtools