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https://github.com/KhronosGroup/SPIRV-Tools
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8013d477ae
This adds a new kind of fact to the fact manager that knows whether a
block is dead - i.e. guaranteed to be statically unreachable - and a
new transformation for adding a selection construct to a CFG that
conditionally branches to a fresh, dead block, such that the branch
will never be dynamically taken. Transformations that may create new
blocks ('split block' and 'outline function') are updated to propagate
dead block facts to newly-created blocks where appropriate. A fuzzer
pass randomly adds dead blocks to the module.
Future transformations will be able to exploit the fact that such
blocks are known to be dead.
64 lines
2.4 KiB
C++
64 lines
2.4 KiB
C++
// Copyright (c) 2019 Google LLC
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#ifndef SOURCE_FUZZ_TRANSFORMATION_SPLIT_BLOCK_H_
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#define SOURCE_FUZZ_TRANSFORMATION_SPLIT_BLOCK_H_
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#include "source/fuzz/fact_manager.h"
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#include "source/fuzz/protobufs/spirvfuzz_protobufs.h"
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#include "source/fuzz/transformation.h"
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#include "source/opt/ir_context.h"
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namespace spvtools {
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namespace fuzz {
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class TransformationSplitBlock : public Transformation {
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public:
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explicit TransformationSplitBlock(
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const protobufs::TransformationSplitBlock& message);
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TransformationSplitBlock(
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const protobufs::InstructionDescriptor& instruction_to_split_before,
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uint32_t fresh_id);
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// - |message_.base_instruction_id| must be the result id of an instruction
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// 'base' in some block 'blk'.
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// - 'blk' must contain an instruction 'inst' located |message_.offset|
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// instructions after 'base' (if |message_.offset| = 0 then 'inst' =
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// 'base').
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// - Splitting 'blk' at 'inst', so that all instructions from 'inst' onwards
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// appear in a new block that 'blk' directly jumps to must be valid.
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// - |message_.fresh_id| must not be used by the module.
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bool IsApplicable(opt::IRContext* context,
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const FactManager& fact_manager) const override;
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// - A new block with label |message_.fresh_id| is inserted right after 'blk'
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// in program order.
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// - All instructions of 'blk' from 'inst' onwards are moved into the new
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// block.
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// - 'blk' is made to jump unconditionally to the new block.
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// - If 'blk' was dead, the new block is also dead.
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void Apply(opt::IRContext* context, FactManager* fact_manager) const override;
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protobufs::Transformation ToMessage() const override;
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private:
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protobufs::TransformationSplitBlock message_;
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};
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} // namespace fuzz
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} // namespace spvtools
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#endif // SOURCE_FUZZ_TRANSFORMATION_SPLIT_BLOCK_H_
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