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// Copyright 2016 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef V8_COMPILER_BYTECODE_LOOP_ANALYSIS_H_
#define V8_COMPILER_BYTECODE_LOOP_ANALYSIS_H_
#include "src/handles.h"
#include "src/zone-containers.h"
namespace v8 {
namespace internal {
class BytecodeArray;
namespace compiler {
class BytecodeBranchAnalysis;
class BytecodeLoopAnalysis BASE_EMBEDDED {
public:
BytecodeLoopAnalysis(Handle<BytecodeArray> bytecode_array,
const BytecodeBranchAnalysis* branch_analysis,
Zone* zone);
// Analyze the bytecodes to find the branch sites and their
// targets. No other methods in this class return valid information
// until this has been called.
void Analyze();
// Get the loop header offset of the containing loop for arbitrary
// {offset}, or -1 if the {offset} is not inside any loop.
int GetLoopOffsetFor(int offset) const;
// Gets the loop header offset of the parent loop of the loop header
// at {header_offset}, or -1 for outer-most loops.
int GetParentLoopFor(int header_offset) const;
private:
void AddLoopEntry(int entry_offset);
void AddBranch(int origin_offset, int target_offset);
Zone* zone() const { return zone_; }
Handle<BytecodeArray> bytecode_array() const { return bytecode_array_; }
Handle<BytecodeArray> bytecode_array_;
const BytecodeBranchAnalysis* branch_analysis_;
Zone* zone_;
int current_loop_offset_;
bool found_current_backedge_;
// Map from the offset of a backedge jump to the offset of the corresponding
// loop header. There might be multiple backedges for do-while loops.
ZoneMap<int, int> backedge_to_header_;
// Map from the offset of a loop header to the offset of its parent's loop
// header. This map will have as many entries as there are loops in the
// function.
ZoneMap<int, int> loop_header_to_parent_;
DISALLOW_COPY_AND_ASSIGN(BytecodeLoopAnalysis);
};
} // namespace compiler
} // namespace internal
} // namespace v8
#endif // V8_COMPILER_BYTECODE_LOOP_ANALYSIS_H_
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