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Diffstat (limited to 'Source/JavaScriptCore/bytecode/BytecodeKills.h')
| -rw-r--r-- | Source/JavaScriptCore/bytecode/BytecodeKills.h | 181 |
1 files changed, 181 insertions, 0 deletions
diff --git a/Source/JavaScriptCore/bytecode/BytecodeKills.h b/Source/JavaScriptCore/bytecode/BytecodeKills.h new file mode 100644 index 000000000..d073ded25 --- /dev/null +++ b/Source/JavaScriptCore/bytecode/BytecodeKills.h @@ -0,0 +1,181 @@ +/* + * Copyright (C) 2015 Apple Inc. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, + * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR + * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS + * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF + * THE POSSIBILITY OF SUCH DAMAGE. + */ + +#ifndef BytecodeKills_h +#define BytecodeKills_h + +#include "CodeBlock.h" +#include <wtf/FastBitVector.h> + +namespace JSC { + +class BytecodeLivenessAnalysis; + +class BytecodeKills { + WTF_MAKE_FAST_ALLOCATED; +public: + BytecodeKills() + : m_codeBlock(nullptr) + { + } + + // By convention, we say that non-local operands are never killed. + bool operandIsKilled(unsigned bytecodeIndex, int operand) const + { + ASSERT_WITH_SECURITY_IMPLICATION(bytecodeIndex < m_codeBlock->instructions().size()); + VirtualRegister reg(operand); + if (reg.isLocal()) + return m_killSets[bytecodeIndex].contains(operand); + return false; + } + + bool operandIsKilled(Instruction* instruction, int operand) const + { + return operandIsKilled(instruction - m_codeBlock->instructions().begin(), operand); + } + + template<typename Functor> + void forEachOperandKilledAt(unsigned bytecodeIndex, const Functor& functor) const + { + ASSERT_WITH_SECURITY_IMPLICATION(bytecodeIndex < m_codeBlock->instructions().size()); + m_killSets[bytecodeIndex].forEachLocal( + [&] (unsigned local) { + functor(virtualRegisterForLocal(local)); + }); + } + + template<typename Functor> + void forEachOperandKilledAt(Instruction* pc, const Functor& functor) const + { + forEachOperandKilledAt(pc - m_codeBlock->instructions().begin(), functor); + } + +private: + friend class BytecodeLivenessAnalysis; + + class KillSet { + public: + KillSet() + : m_word(0) + { + } + + ~KillSet() + { + if (hasVector()) + delete vector(); + } + + void add(unsigned local) + { + if (isEmpty()) { + setOneItem(local); + return; + } + if (hasOneItem()) { + ASSERT(oneItem() != local); + Vector<unsigned>* vector = new Vector<unsigned>(); + vector->append(oneItem()); + vector->append(local); + setVector(vector); + return; + } + ASSERT(!vector()->contains(local)); + vector()->append(local); + } + + template<typename Functor> + void forEachLocal(const Functor& functor) + { + if (isEmpty()) + return; + if (hasOneItem()) { + functor(oneItem()); + return; + } + for (unsigned local : *vector()) + functor(local); + } + + bool contains(unsigned expectedLocal) + { + if (isEmpty()) + return false; + if (hasOneItem()) + return oneItem() == expectedLocal; + for (unsigned local : *vector()) { + if (local == expectedLocal) + return true; + } + return false; + } + + private: + bool isEmpty() const + { + return !m_word; + } + + bool hasOneItem() const + { + return m_word & 1; + } + + unsigned oneItem() const + { + return m_word >> 1; + } + + void setOneItem(unsigned value) + { + m_word = (value << 1) | 1; + } + + bool hasVector() const + { + return !isEmpty() && !hasOneItem(); + } + + Vector<unsigned>* vector() + { + return bitwise_cast<Vector<unsigned>*>(m_word); + } + + void setVector(Vector<unsigned>* value) + { + m_word = bitwise_cast<uintptr_t>(value); + } + + uintptr_t m_word; + }; + + CodeBlock* m_codeBlock; + std::unique_ptr<KillSet[]> m_killSets; +}; + +} // namespace JSC + +#endif // BytecodeKills_h + |