v8/src/interpreter/bytecode-array-random-iterator.h
leszeks b9d930735a [ignition] Rewrite reverse iterator as random iterator
This allows us to optimise the bytecode liveness analysis to jump
directly to previously seen indices. The analysis is optimised to store
a stack of loop ends (JumpLoop bytecode indices), and iterate through
these indices directly rather than looping through the bytecode array to
find them.

Review-Url: https://codereview.chromium.org/2536653003
Cr-Commit-Position: refs/heads/master@{#41485}
2016-12-05 13:03:43 +00:00

79 lines
1.9 KiB
C++

// 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_INTERPRETER_BYTECODE_ARRAY_RANDOM_ITERATOR_H_
#define V8_INTERPRETER_BYTECODE_ARRAY_RANDOM_ITERATOR_H_
#include "src/interpreter/bytecode-array-accessor.h"
#include "src/zone/zone-containers.h"
#include "src/zone/zone.h"
namespace v8 {
namespace internal {
namespace interpreter {
class V8_EXPORT_PRIVATE BytecodeArrayRandomIterator final
: public BytecodeArrayAccessor {
public:
explicit BytecodeArrayRandomIterator(Handle<BytecodeArray> bytecode_array,
Zone* zone);
BytecodeArrayRandomIterator& operator++() {
++current_index_;
UpdateOffsetFromIndex();
return *this;
}
BytecodeArrayRandomIterator& operator--() {
--current_index_;
UpdateOffsetFromIndex();
return *this;
}
BytecodeArrayRandomIterator& operator+=(int offset) {
current_index_ += offset;
UpdateOffsetFromIndex();
return *this;
}
BytecodeArrayRandomIterator& operator-=(int offset) {
current_index_ -= offset;
UpdateOffsetFromIndex();
return *this;
}
int current_index() const { return current_index_; }
size_t size() const { return offsets_.size(); }
void GoToIndex(int index) {
current_index_ = index;
UpdateOffsetFromIndex();
}
void GoToStart() {
current_index_ = 0;
UpdateOffsetFromIndex();
}
void GoToEnd() {
DCHECK_LT(offsets_.size() - 1, static_cast<size_t>(INT_MAX));
current_index_ = static_cast<int>(offsets_.size() - 1);
UpdateOffsetFromIndex();
}
bool IsValid() const;
private:
ZoneVector<int> offsets_;
int current_index_;
void UpdateOffsetFromIndex();
DISALLOW_COPY_AND_ASSIGN(BytecodeArrayRandomIterator);
};
} // namespace interpreter
} // namespace internal
} // namespace v8
#endif // V8_INTERPRETER_BYTECODE_ARRAY_RANDOM_ITERATOR_H_