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// Copyright (c) 2020 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_REPLACE_BRANCH_FROM_DEAD_BLOCK_WITH_EXIT_H_
#define SOURCE_FUZZ_TRANSFORMATION_REPLACE_BRANCH_FROM_DEAD_BLOCK_WITH_EXIT_H_
#include "source/fuzz/protobufs/spirvfuzz_protobufs.h"
#include "source/fuzz/transformation.h"
#include "source/fuzz/transformation_context.h"
#include "source/opt/basic_block.h"
#include "source/opt/ir_context.h"
namespace spvtools {
namespace fuzz {
class TransformationReplaceBranchFromDeadBlockWithExit : public Transformation {
public:
explicit TransformationReplaceBranchFromDeadBlockWithExit(
protobufs::TransformationReplaceBranchFromDeadBlockWithExit message);
TransformationReplaceBranchFromDeadBlockWithExit(uint32_t block_id,
spv::Op opcode,
uint32_t return_value_id);
// - |message_.block_id| must be the id of a dead block that is not part of
// a continue construct
// - |message_.block_id| must end with OpBranch
// - The successor of |message_.block_id| must have at least one other
// predecessor
// - |message_.opcode()| must be one of OpKill, OpReturn, OpReturnValue and
// OpUnreachable
// - |message_.opcode()| can only be OpKill if the module's entry points all
// have Fragment execution mode
// - |message_.opcode()| can only be OpReturn if the return type of the
// function containing the block is void
// - If |message_.opcode()| is OpReturnValue then |message_.return_value_id|
// must be an id that is available at the block terminator and that matches
// the return type of the enclosing function
// - Domination rules should be preserved when we apply this transformation.
// In particular, if some block appears after the |block_id|'s successor in
// the CFG, then that block cannot dominate |block_id|'s successor when this
// transformation is applied.
bool IsApplicable(
opt::IRContext* ir_context,
const TransformationContext& transformation_context) const override;
// Changes the terminator of |message_.block_id| to have opcode
// |message_.opcode|, additionally with input operand
// |message_.return_value_id| in the case that |message_.opcode| is
// OpReturnValue.
//
// If |message_.block_id|'s successor starts with OpPhi instructions these are
// updated so that they no longer refer to |message_.block_id|.
void Apply(opt::IRContext* ir_context,
TransformationContext* transformation_context) const override;
std::unordered_set<uint32_t> GetFreshIds() const override;
protobufs::Transformation ToMessage() const override;
// Returns true if and only if |block| meets the criteria for having its
// terminator replaced with an early exit (see IsApplicable for details of the
// criteria.)
static bool BlockIsSuitable(
opt::IRContext* ir_context,
const TransformationContext& transformation_context,
const opt::BasicBlock& block);
private:
protobufs::TransformationReplaceBranchFromDeadBlockWithExit message_;
};
} // namespace fuzz
} // namespace spvtools
#endif // SOURCE_FUZZ_TRANSFORMATION_REPLACE_BRANCH_FROM_DEAD_BLOCK_WITH_EXIT_H_