SPIRV-Tools/source/fuzz/transformation_add_dead_break.h
Alastair Donaldson 1a89ac8b28
Transformation and fuzzer pass to add dead continues (#2758)
Similar to the existing 'add dead breaks' pass, this adds a pass to
add dead continues to blocks in loops where such a transformation is
viable.  Various functionality common to this new pass and 'add dead
breaks' has been factored into 'fuzzer_util', and some small
improvements to 'add dead breaks' that were identified while reviewing
that code again have been applied.

Fixes #2719.
2019-07-25 13:50:33 +01:00

75 lines
3.0 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.
#ifndef SOURCE_FUZZ_TRANSFORMATION_ADD_DEAD_BREAK_H_
#define SOURCE_FUZZ_TRANSFORMATION_ADD_DEAD_BREAK_H_
#include <vector>
#include "source/fuzz/fact_manager.h"
#include "source/fuzz/protobufs/spirvfuzz_protobufs.h"
#include "source/fuzz/transformation.h"
#include "source/opt/ir_context.h"
namespace spvtools {
namespace fuzz {
class TransformationAddDeadBreak : public Transformation {
public:
explicit TransformationAddDeadBreak(
const protobufs::TransformationAddDeadBreak& message);
TransformationAddDeadBreak(uint32_t from_block, uint32_t to_block,
bool break_condition_value,
std::vector<uint32_t> phi_id);
// - |message_.from_block| must be the id of a block a in the given module.
// - |message_.to_block| must be the id of a block b in the given module.
// - if |message_.break_condition_value| holds (does not hold) then
// OpConstantTrue (OpConstantFalse) must be present in the module
// - |message_.phi_ids| must be a list of ids that are all available at
// |message_.from_block|
// - a and b must be in the same function.
// - b must be a merge block.
// - a must end with an unconditional branch to some block c.
// - replacing this branch with a conditional branch to b or c, with
// the boolean constant associated with |message_.break_condition_value| as
// the condition, and the ids in |message_.phi_ids| used to extend
// any OpPhi instructions at b as a result of the edge from a, must
// maintain validity of the module.
bool IsApplicable(opt::IRContext* context,
const FactManager& fact_manager) const override;
// Replaces the terminator of a with a conditional branch to b or c.
// The boolean constant associated with |message_.break_condition_value| is
// used as the condition, and the order of b and c is arranged such that
// control is guaranteed to jump to c.
void Apply(opt::IRContext* context, FactManager* fact_manager) const override;
protobufs::Transformation ToMessage() const override;
private:
// Returns true if and only if adding an edge from |bb_from| to
// |message_.to_block| respects structured control flow.
bool AddingBreakRespectsStructuredControlFlow(opt::IRContext* context,
opt::BasicBlock* bb_from) const;
protobufs::TransformationAddDeadBreak message_;
};
} // namespace fuzz
} // namespace spvtools
#endif // SOURCE_FUZZ_TRANSFORMATION_ADD_DEAD_BREAK_H_