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Diffstat (limited to 'JavaScriptCore/assembler/LinkBuffer.h')
| -rw-r--r-- | JavaScriptCore/assembler/LinkBuffer.h | 350 |
1 files changed, 0 insertions, 350 deletions
diff --git a/JavaScriptCore/assembler/LinkBuffer.h b/JavaScriptCore/assembler/LinkBuffer.h deleted file mode 100644 index e38b9d4..0000000 --- a/JavaScriptCore/assembler/LinkBuffer.h +++ /dev/null @@ -1,350 +0,0 @@ -/* - * Copyright (C) 2009, 2010 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. ``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 - * 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 LinkBuffer_h -#define LinkBuffer_h - -#if ENABLE(ASSEMBLER) - -#define DUMP_LINK_STATISTICS 0 -#define DUMP_CODE 0 - -#include <MacroAssembler.h> -#include <wtf/Noncopyable.h> - -namespace JSC { - -// LinkBuffer: -// -// This class assists in linking code generated by the macro assembler, once code generation -// has been completed, and the code has been copied to is final location in memory. At this -// time pointers to labels within the code may be resolved, and relative offsets to external -// addresses may be fixed. -// -// Specifically: -// * Jump objects may be linked to external targets, -// * The address of Jump objects may taken, such that it can later be relinked. -// * The return address of a Call may be acquired. -// * The address of a Label pointing into the code may be resolved. -// * The value referenced by a DataLabel may be set. -// -class LinkBuffer : public Noncopyable { - typedef MacroAssemblerCodeRef CodeRef; - typedef MacroAssemblerCodePtr CodePtr; - typedef MacroAssembler::Label Label; - typedef MacroAssembler::Jump Jump; - typedef MacroAssembler::JumpList JumpList; - typedef MacroAssembler::Call Call; - typedef MacroAssembler::DataLabel32 DataLabel32; - typedef MacroAssembler::DataLabelPtr DataLabelPtr; - typedef MacroAssembler::JmpDst JmpDst; -#if ENABLE(BRANCH_COMPACTION) - typedef MacroAssembler::LinkRecord LinkRecord; - typedef MacroAssembler::JumpLinkType JumpLinkType; -#endif - -public: - // Note: Initialization sequence is significant, since executablePool is a PassRefPtr. - // First, executablePool is copied into m_executablePool, then the initialization of - // m_code uses m_executablePool, *not* executablePool, since this is no longer valid. - // The linkOffset parameter should only be non-null when recompiling for exception info - LinkBuffer(MacroAssembler* masm, PassRefPtr<ExecutablePool> executablePool, void* linkOffset) - : m_executablePool(executablePool) - , m_size(0) - , m_code(0) - , m_assembler(masm) -#ifndef NDEBUG - , m_completed(false) -#endif - { - linkCode(linkOffset); - } - - ~LinkBuffer() - { - ASSERT(m_completed); - } - - // These methods are used to link or set values at code generation time. - - void link(Call call, FunctionPtr function) - { - ASSERT(call.isFlagSet(Call::Linkable)); - call.m_jmp = applyOffset(call.m_jmp); - MacroAssembler::linkCall(code(), call, function); - } - - void link(Jump jump, CodeLocationLabel label) - { - jump.m_jmp = applyOffset(jump.m_jmp); - MacroAssembler::linkJump(code(), jump, label); - } - - void link(JumpList list, CodeLocationLabel label) - { - for (unsigned i = 0; i < list.m_jumps.size(); ++i) - link(list.m_jumps[i], label); - } - - void patch(DataLabelPtr label, void* value) - { - JmpDst target = applyOffset(label.m_label); - MacroAssembler::linkPointer(code(), target, value); - } - - void patch(DataLabelPtr label, CodeLocationLabel value) - { - JmpDst target = applyOffset(label.m_label); - MacroAssembler::linkPointer(code(), target, value.executableAddress()); - } - - // These methods are used to obtain handles to allow the code to be relinked / repatched later. - - CodeLocationCall locationOf(Call call) - { - ASSERT(call.isFlagSet(Call::Linkable)); - ASSERT(!call.isFlagSet(Call::Near)); - return CodeLocationCall(MacroAssembler::getLinkerAddress(code(), applyOffset(call.m_jmp))); - } - - CodeLocationNearCall locationOfNearCall(Call call) - { - ASSERT(call.isFlagSet(Call::Linkable)); - ASSERT(call.isFlagSet(Call::Near)); - return CodeLocationNearCall(MacroAssembler::getLinkerAddress(code(), applyOffset(call.m_jmp))); - } - - CodeLocationLabel locationOf(Label label) - { - return CodeLocationLabel(MacroAssembler::getLinkerAddress(code(), applyOffset(label.m_label))); - } - - CodeLocationDataLabelPtr locationOf(DataLabelPtr label) - { - return CodeLocationDataLabelPtr(MacroAssembler::getLinkerAddress(code(), applyOffset(label.m_label))); - } - - CodeLocationDataLabel32 locationOf(DataLabel32 label) - { - return CodeLocationDataLabel32(MacroAssembler::getLinkerAddress(code(), applyOffset(label.m_label))); - } - - // This method obtains the return address of the call, given as an offset from - // the start of the code. - unsigned returnAddressOffset(Call call) - { - call.m_jmp = applyOffset(call.m_jmp); - return MacroAssembler::getLinkerCallReturnOffset(call); - } - - // Upon completion of all patching either 'finalizeCode()' or 'finalizeCodeAddendum()' should be called - // once to complete generation of the code. 'finalizeCode()' is suited to situations - // where the executable pool must also be retained, the lighter-weight 'finalizeCodeAddendum()' is - // suited to adding to an existing allocation. - CodeRef finalizeCode() - { - performFinalization(); - - return CodeRef(m_code, m_executablePool, m_size); - } - - CodeLocationLabel finalizeCodeAddendum() - { - performFinalization(); - - return CodeLocationLabel(code()); - } - - CodePtr trampolineAt(Label label) - { - return CodePtr(MacroAssembler::AssemblerType_T::getRelocatedAddress(code(), applyOffset(label.m_label))); - } - -private: - template <typename T> T applyOffset(T src) - { -#if ENABLE(BRANCH_COMPACTION) - src.m_offset -= m_assembler->executableOffsetFor(src.m_offset); -#endif - return src; - } - - // Keep this private! - the underlying code should only be obtained externally via - // finalizeCode() or finalizeCodeAddendum(). - void* code() - { - return m_code; - } - - void linkCode(void* linkOffset) - { - UNUSED_PARAM(linkOffset); - ASSERT(!m_code); -#if !ENABLE(BRANCH_COMPACTION) - m_code = m_assembler->m_assembler.executableCopy(m_executablePool.get()); - m_size = m_assembler->size(); -#else - size_t initialSize = m_assembler->size(); - m_code = (uint8_t*)m_executablePool->alloc(initialSize); - if (!m_code) - return; - ExecutableAllocator::makeWritable(m_code, m_assembler->size()); - uint8_t* inData = (uint8_t*)m_assembler->unlinkedCode(); - uint8_t* outData = reinterpret_cast<uint8_t*>(m_code); - const uint8_t* linkBase = linkOffset ? reinterpret_cast<uint8_t*>(linkOffset) : outData; - int readPtr = 0; - int writePtr = 0; - Vector<LinkRecord>& jumpsToLink = m_assembler->jumpsToLink(); - unsigned jumpCount = jumpsToLink.size(); - for (unsigned i = 0; i < jumpCount; ++i) { - int offset = readPtr - writePtr; - ASSERT(!(offset & 1)); - - // Copy the instructions from the last jump to the current one. - size_t regionSize = jumpsToLink[i].from() - readPtr; - memcpy(outData + writePtr, inData + readPtr, regionSize); - m_assembler->recordLinkOffsets(readPtr, jumpsToLink[i].from(), offset); - readPtr += regionSize; - writePtr += regionSize; - - // Calculate absolute address of the jump target, in the case of backwards - // branches we need to be precise, forward branches we are pessimistic - const uint8_t* target; - if (jumpsToLink[i].to() >= jumpsToLink[i].from()) - target = linkBase + jumpsToLink[i].to() - offset; // Compensate for what we have collapsed so far - else - target = linkBase + jumpsToLink[i].to() - m_assembler->executableOffsetFor(jumpsToLink[i].to()); - - JumpLinkType jumpLinkType = m_assembler->computeJumpType(jumpsToLink[i], linkBase + writePtr, target); - // Compact branch if we can... - if (m_assembler->canCompact(jumpsToLink[i].type())) { - // Step back in the write stream - int32_t delta = m_assembler->jumpSizeDelta(jumpsToLink[i].type(), jumpLinkType); - if (delta) { - writePtr -= delta; - m_assembler->recordLinkOffsets(jumpsToLink[i].from() - delta, readPtr, readPtr - writePtr); - } - } - jumpsToLink[i].setFrom(writePtr); - } - // Copy everything after the last jump - memcpy(outData + writePtr, inData + readPtr, m_assembler->size() - readPtr); - m_assembler->recordLinkOffsets(readPtr, m_assembler->size(), readPtr - writePtr); - - // Actually link everything (don't link if we've be given a linkoffset as it's a - // waste of time: linkOffset is used for recompiling to get exception info) - if (!linkOffset) { - for (unsigned i = 0; i < jumpCount; ++i) { - uint8_t* location = outData + jumpsToLink[i].from(); - uint8_t* target = outData + jumpsToLink[i].to() - m_assembler->executableOffsetFor(jumpsToLink[i].to()); - m_assembler->link(jumpsToLink[i], location, target); - } - } - - jumpsToLink.clear(); - m_size = writePtr + m_assembler->size() - readPtr; - m_executablePool->tryShrink(m_code, initialSize, m_size); - -#if DUMP_LINK_STATISTICS - dumpLinkStatistics(m_code, initialSize, m_size); -#endif -#if DUMP_CODE - dumpCode(m_code, m_size); -#endif -#endif - } - - void performFinalization() - { -#ifndef NDEBUG - ASSERT(!m_completed); - m_completed = true; -#endif - - ExecutableAllocator::makeExecutable(code(), m_size); - ExecutableAllocator::cacheFlush(code(), m_size); - } - -#if DUMP_LINK_STATISTICS - static void dumpLinkStatistics(void* code, size_t initialSize, size_t finalSize) - { - static unsigned linkCount = 0; - static unsigned totalInitialSize = 0; - static unsigned totalFinalSize = 0; - linkCount++; - totalInitialSize += initialSize; - totalFinalSize += finalSize; - printf("link %p: orig %u, compact %u (delta %u, %.2f%%)\n", - code, static_cast<unsigned>(initialSize), static_cast<unsigned>(finalSize), - static_cast<unsigned>(initialSize - finalSize), - 100.0 * (initialSize - finalSize) / initialSize); - printf("\ttotal %u: orig %u, compact %u (delta %u, %.2f%%)\n", - linkCount, totalInitialSize, totalFinalSize, totalInitialSize - totalFinalSize, - 100.0 * (totalInitialSize - totalFinalSize) / totalInitialSize); - } -#endif - -#if DUMP_CODE - static void dumpCode(void* code, size_t size) - { -#if CPU(ARM_THUMB2) - // Dump the generated code in an asm file format that can be assembled and then disassembled - // for debugging purposes. For example, save this output as jit.s: - // gcc -arch armv7 -c jit.s - // otool -tv jit.o - static unsigned codeCount = 0; - unsigned short* tcode = static_cast<unsigned short*>(code); - size_t tsize = size / sizeof(short); - char nameBuf[128]; - snprintf(nameBuf, sizeof(nameBuf), "_jsc_jit%u", codeCount++); - printf("\t.syntax unified\n" - "\t.section\t__TEXT,__text,regular,pure_instructions\n" - "\t.globl\t%s\n" - "\t.align 2\n" - "\t.code 16\n" - "\t.thumb_func\t%s\n" - "# %p\n" - "%s:\n", nameBuf, nameBuf, code, nameBuf); - - for (unsigned i = 0; i < tsize; i++) - printf("\t.short\t0x%x\n", tcode[i]); -#endif - } -#endif - - RefPtr<ExecutablePool> m_executablePool; - size_t m_size; - void* m_code; - MacroAssembler* m_assembler; -#ifndef NDEBUG - bool m_completed; -#endif -}; - -} // namespace JSC - -#endif // ENABLE(ASSEMBLER) - -#endif // LinkBuffer_h |