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/*
* Copyright (C) 2012, 2013 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.
*/
#include "config.h"
#include "LinkBuffer.h"
#if ENABLE(ASSEMBLER)
#include "Options.h"
#include "VM.h"
#include <wtf/CompilationThread.h>
namespace JSC {
LinkBuffer::CodeRef LinkBuffer::finalizeCodeWithoutDisassembly()
{
performFinalization();
ASSERT(m_didAllocate);
if (m_executableMemory)
return CodeRef(m_executableMemory);
return CodeRef::createSelfManagedCodeRef(MacroAssemblerCodePtr(m_code));
}
LinkBuffer::CodeRef LinkBuffer::finalizeCodeWithDisassembly(const char* format, ...)
{
ASSERT(Options::showDisassembly() || Options::showDFGDisassembly());
CodeRef result = finalizeCodeWithoutDisassembly();
#if ENABLE(DISASSEMBLER)
dataLogF("Generated JIT code for ");
va_list argList;
va_start(argList, format);
WTF::dataLogFV(format, argList);
va_end(argList);
dataLogF(":\n");
dataLogF(" Code at [%p, %p):\n", result.code().executableAddress(), static_cast<char*>(result.code().executableAddress()) + result.size());
disassemble(result.code(), m_size, " ", WTF::dataFile());
#else
UNUSED_PARAM(format);
#endif // ENABLE(DISASSEMBLER)
return result;
}
#if ENABLE(BRANCH_COMPACTION)
template <typename InstructionType>
void LinkBuffer::copyCompactAndLinkCode(void* ownerUID, JITCompilationEffort effort)
{
m_initialSize = m_assembler->m_assembler.codeSize();
allocate(m_initialSize, ownerUID, effort);
uint8_t* inData = (uint8_t*)m_assembler->unlinkedCode();
uint8_t* outData = reinterpret_cast<uint8_t*>(m_code);
int readPtr = 0;
int writePtr = 0;
Vector<LinkRecord, 0, UnsafeVectorOverflow>& 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;
InstructionType* copySource = reinterpret_cast_ptr<InstructionType*>(inData + readPtr);
InstructionType* copyEnd = reinterpret_cast_ptr<InstructionType*>(inData + readPtr + regionSize);
InstructionType* copyDst = reinterpret_cast_ptr<InstructionType*>(outData + writePtr);
ASSERT(!(regionSize % 2));
ASSERT(!(readPtr % 2));
ASSERT(!(writePtr % 2));
while (copySource != copyEnd)
*copyDst++ = *copySource++;
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 = outData + jumpsToLink[i].to() - offset; // Compensate for what we have collapsed so far
else
target = outData + jumpsToLink[i].to() - m_assembler->executableOffsetFor(jumpsToLink[i].to());
JumpLinkType jumpLinkType = m_assembler->computeJumpType(jumpsToLink[i], outData + 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_initialSize - readPtr);
m_assembler->recordLinkOffsets(readPtr, m_initialSize, readPtr - writePtr);
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();
shrink(writePtr + m_initialSize - readPtr);
#if DUMP_LINK_STATISTICS
dumpLinkStatistics(m_code, m_initialSize, m_size);
#endif
#if DUMP_CODE
dumpCode(m_code, m_size);
#endif
}
#endif
void LinkBuffer::linkCode(void* ownerUID, JITCompilationEffort effort)
{
#if !ENABLE(BRANCH_COMPACTION)
#if defined(ASSEMBLER_HAS_CONSTANT_POOL) && ASSEMBLER_HAS_CONSTANT_POOL
m_assembler->m_assembler.buffer().flushConstantPool(false);
#endif
AssemblerBuffer& buffer = m_assembler->m_assembler.buffer();
allocate(buffer.codeSize(), ownerUID, effort);
if (!m_didAllocate)
return;
ASSERT(m_code);
#if CPU(ARM_TRADITIONAL)
m_assembler->m_assembler.prepareExecutableCopy(m_code);
#endif
memcpy(m_code, buffer.data(), buffer.codeSize());
#if CPU(MIPS)
m_assembler->m_assembler.relocateJumps(buffer.data(), m_code);
#endif
#elif CPU(ARM_THUMB2)
copyCompactAndLinkCode<uint16_t>(ownerUID, effort);
#elif CPU(ARM64)
copyCompactAndLinkCode<uint32_t>(ownerUID, effort);
#endif
}
void LinkBuffer::allocate(size_t initialSize, void* ownerUID, JITCompilationEffort effort)
{
if (m_code) {
if (initialSize > m_size)
return;
m_didAllocate = true;
m_size = initialSize;
return;
}
m_executableMemory = m_vm->executableAllocator.allocate(*m_vm, initialSize, ownerUID, effort);
if (!m_executableMemory)
return;
ExecutableAllocator::makeWritable(m_executableMemory->start(), m_executableMemory->sizeInBytes());
m_code = m_executableMemory->start();
m_size = initialSize;
m_didAllocate = true;
}
void LinkBuffer::shrink(size_t newSize)
{
m_size = newSize;
m_executableMemory->shrink(m_size);
}
void LinkBuffer::performFinalization()
{
#ifndef NDEBUG
ASSERT(!isCompilationThread());
ASSERT(!m_completed);
ASSERT(isValid());
m_completed = true;
#endif
#if ENABLE(BRANCH_COMPACTION)
ExecutableAllocator::makeExecutable(code(), m_initialSize);
#else
ExecutableAllocator::makeExecutable(code(), m_size);
#endif
MacroAssembler::cacheFlush(code(), m_size);
}
#if DUMP_LINK_STATISTICS
void LinkBuffer::dumpLinkStatistics(void* code, size_t initializeSize, size_t finalSize)
{
static unsigned linkCount = 0;
static unsigned totalInitialSize = 0;
static unsigned totalFinalSize = 0;
linkCount++;
totalInitialSize += initialSize;
totalFinalSize += finalSize;
dataLogF("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);
dataLogF("\ttotal %u: orig %u, compact %u (delta %u, %.2f%%)\n",
linkCount, totalInitialSize, totalFinalSize, totalInitialSize - totalFinalSize,
100.0 * (totalInitialSize - totalFinalSize) / totalInitialSize);
}
#endif
#if DUMP_CODE
void LinkBuffer::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++);
dataLogF("\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++)
dataLogF("\t.short\t0x%x\n", tcode[i]);
#elif CPU(ARM_TRADITIONAL)
// gcc -c jit.s
// objdump -D jit.o
static unsigned codeCount = 0;
unsigned int* tcode = static_cast<unsigned int*>(code);
size_t tsize = size / sizeof(unsigned int);
char nameBuf[128];
snprintf(nameBuf, sizeof(nameBuf), "_jsc_jit%u", codeCount++);
dataLogF("\t.globl\t%s\n"
"\t.align 4\n"
"\t.code 32\n"
"\t.text\n"
"# %p\n"
"%s:\n", nameBuf, code, nameBuf);
for (unsigned i = 0; i < tsize; i++)
dataLogF("\t.long\t0x%x\n", tcode[i]);
#endif
}
#endif
} // namespace JSC
#endif // ENABLE(ASSEMBLER)