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93a37866 1/*
81345200 2 * Copyright (C) 2012, 2013, 2014 Apple Inc. All rights reserved.
93a37866
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3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#include "config.h"
27#include "LinkBuffer.h"
28
29#if ENABLE(ASSEMBLER)
30
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31#include "CodeBlock.h"
32#include "JITCode.h"
33#include "JSCInlines.h"
93a37866 34#include "Options.h"
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35#include "VM.h"
36#include <wtf/CompilationThread.h>
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37
38namespace JSC {
39
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40bool shouldShowDisassemblyFor(CodeBlock* codeBlock)
41{
42 if (JITCode::isOptimizingJIT(codeBlock->jitType()) && Options::showDFGDisassembly())
43 return true;
44 return Options::showDisassembly();
45}
46
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47LinkBuffer::CodeRef LinkBuffer::finalizeCodeWithoutDisassembly()
48{
49 performFinalization();
50
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51 ASSERT(m_didAllocate);
52 if (m_executableMemory)
53 return CodeRef(m_executableMemory);
54
55 return CodeRef::createSelfManagedCodeRef(MacroAssemblerCodePtr(m_code));
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56}
57
58LinkBuffer::CodeRef LinkBuffer::finalizeCodeWithDisassembly(const char* format, ...)
59{
93a37866 60 CodeRef result = finalizeCodeWithoutDisassembly();
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61
62#if ENABLE(DISASSEMBLER)
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63 dataLogF("Generated JIT code for ");
64 va_list argList;
65 va_start(argList, format);
66 WTF::dataLogFV(format, argList);
67 va_end(argList);
68 dataLogF(":\n");
69
70 dataLogF(" Code at [%p, %p):\n", result.code().executableAddress(), static_cast<char*>(result.code().executableAddress()) + result.size());
71 disassemble(result.code(), m_size, " ", WTF::dataFile());
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72#else
73 UNUSED_PARAM(format);
74#endif // ENABLE(DISASSEMBLER)
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75
76 return result;
77}
78
79#if ENABLE(BRANCH_COMPACTION)
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80static ALWAYS_INLINE void recordLinkOffsets(AssemblerData& assemblerData, int32_t regionStart, int32_t regionEnd, int32_t offset)
81{
82 int32_t ptr = regionStart / sizeof(int32_t);
83 const int32_t end = regionEnd / sizeof(int32_t);
84 int32_t* offsets = reinterpret_cast<int32_t*>(assemblerData.buffer());
85 while (ptr < end)
86 offsets[ptr++] = offset;
87}
88
93a37866 89template <typename InstructionType>
81345200 90void LinkBuffer::copyCompactAndLinkCode(MacroAssembler& macroAssembler, void* ownerUID, JITCompilationEffort effort)
93a37866 91{
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92 m_initialSize = macroAssembler.m_assembler.codeSize();
93 allocate(m_initialSize, ownerUID, effort);
94 if (didFailToAllocate())
93a37866 95 return;
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96 Vector<LinkRecord, 0, UnsafeVectorOverflow>& jumpsToLink = macroAssembler.jumpsToLink();
97 m_assemblerStorage = macroAssembler.m_assembler.buffer().releaseAssemblerData();
98 uint8_t* inData = reinterpret_cast<uint8_t*>(m_assemblerStorage.buffer());
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99 uint8_t* outData = reinterpret_cast<uint8_t*>(m_code);
100 int readPtr = 0;
101 int writePtr = 0;
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102 unsigned jumpCount = jumpsToLink.size();
103 for (unsigned i = 0; i < jumpCount; ++i) {
104 int offset = readPtr - writePtr;
105 ASSERT(!(offset & 1));
106
107 // Copy the instructions from the last jump to the current one.
108 size_t regionSize = jumpsToLink[i].from() - readPtr;
109 InstructionType* copySource = reinterpret_cast_ptr<InstructionType*>(inData + readPtr);
110 InstructionType* copyEnd = reinterpret_cast_ptr<InstructionType*>(inData + readPtr + regionSize);
111 InstructionType* copyDst = reinterpret_cast_ptr<InstructionType*>(outData + writePtr);
112 ASSERT(!(regionSize % 2));
113 ASSERT(!(readPtr % 2));
114 ASSERT(!(writePtr % 2));
115 while (copySource != copyEnd)
116 *copyDst++ = *copySource++;
81345200 117 recordLinkOffsets(m_assemblerStorage, readPtr, jumpsToLink[i].from(), offset);
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118 readPtr += regionSize;
119 writePtr += regionSize;
120
121 // Calculate absolute address of the jump target, in the case of backwards
122 // branches we need to be precise, forward branches we are pessimistic
123 const uint8_t* target;
124 if (jumpsToLink[i].to() >= jumpsToLink[i].from())
125 target = outData + jumpsToLink[i].to() - offset; // Compensate for what we have collapsed so far
126 else
81345200 127 target = outData + jumpsToLink[i].to() - executableOffsetFor(jumpsToLink[i].to());
93a37866 128
81345200 129 JumpLinkType jumpLinkType = MacroAssembler::computeJumpType(jumpsToLink[i], outData + writePtr, target);
93a37866 130 // Compact branch if we can...
81345200 131 if (MacroAssembler::canCompact(jumpsToLink[i].type())) {
93a37866 132 // Step back in the write stream
81345200 133 int32_t delta = MacroAssembler::jumpSizeDelta(jumpsToLink[i].type(), jumpLinkType);
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134 if (delta) {
135 writePtr -= delta;
81345200 136 recordLinkOffsets(m_assemblerStorage, jumpsToLink[i].from() - delta, readPtr, readPtr - writePtr);
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137 }
138 }
139 jumpsToLink[i].setFrom(writePtr);
140 }
141 // Copy everything after the last jump
142 memcpy(outData + writePtr, inData + readPtr, m_initialSize - readPtr);
81345200 143 recordLinkOffsets(m_assemblerStorage, readPtr, m_initialSize, readPtr - writePtr);
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144
145 for (unsigned i = 0; i < jumpCount; ++i) {
146 uint8_t* location = outData + jumpsToLink[i].from();
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147 uint8_t* target = outData + jumpsToLink[i].to() - executableOffsetFor(jumpsToLink[i].to());
148 MacroAssembler::link(jumpsToLink[i], location, target);
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149 }
150
151 jumpsToLink.clear();
81345200 152 shrink(writePtr + m_initialSize - readPtr);
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153
154#if DUMP_LINK_STATISTICS
155 dumpLinkStatistics(m_code, m_initialSize, m_size);
156#endif
157#if DUMP_CODE
158 dumpCode(m_code, m_size);
159#endif
160}
161#endif
162
163
81345200 164void LinkBuffer::linkCode(MacroAssembler& macroAssembler, void* ownerUID, JITCompilationEffort effort)
93a37866 165{
93a37866 166#if !ENABLE(BRANCH_COMPACTION)
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167#if defined(ASSEMBLER_HAS_CONSTANT_POOL) && ASSEMBLER_HAS_CONSTANT_POOL
168 macroAssembler.m_assembler.buffer().flushConstantPool(false);
169#endif
170 AssemblerBuffer& buffer = macroAssembler.m_assembler.buffer();
171 allocate(buffer.codeSize(), ownerUID, effort);
172 if (!m_didAllocate)
93a37866 173 return;
93a37866 174 ASSERT(m_code);
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175#if CPU(ARM_TRADITIONAL)
176 macroAssembler.m_assembler.prepareExecutableCopy(m_code);
177#endif
178 memcpy(m_code, buffer.data(), buffer.codeSize());
179#if CPU(MIPS)
180 macroAssembler.m_assembler.relocateJumps(buffer.data(), m_code);
181#endif
93a37866 182#elif CPU(ARM_THUMB2)
81345200 183 copyCompactAndLinkCode<uint16_t>(macroAssembler, ownerUID, effort);
93a37866 184#elif CPU(ARM64)
81345200 185 copyCompactAndLinkCode<uint32_t>(macroAssembler, ownerUID, effort);
93a37866
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186#endif
187}
188
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189void LinkBuffer::allocate(size_t initialSize, void* ownerUID, JITCompilationEffort effort)
190{
191 if (m_code) {
192 if (initialSize > m_size)
193 return;
194
195 m_didAllocate = true;
196 m_size = initialSize;
197 return;
198 }
199
200 m_executableMemory = m_vm->executableAllocator.allocate(*m_vm, initialSize, ownerUID, effort);
201 if (!m_executableMemory)
202 return;
203 ExecutableAllocator::makeWritable(m_executableMemory->start(), m_executableMemory->sizeInBytes());
204 m_code = m_executableMemory->start();
205 m_size = initialSize;
206 m_didAllocate = true;
207}
208
209void LinkBuffer::shrink(size_t newSize)
210{
211 if (!m_executableMemory)
212 return;
213 m_size = newSize;
214 m_executableMemory->shrink(m_size);
215}
216
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217void LinkBuffer::performFinalization()
218{
219#ifndef NDEBUG
81345200 220 ASSERT(!isCompilationThread());
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221 ASSERT(!m_completed);
222 ASSERT(isValid());
223 m_completed = true;
224#endif
225
226#if ENABLE(BRANCH_COMPACTION)
227 ExecutableAllocator::makeExecutable(code(), m_initialSize);
228#else
229 ExecutableAllocator::makeExecutable(code(), m_size);
230#endif
231 MacroAssembler::cacheFlush(code(), m_size);
232}
233
234#if DUMP_LINK_STATISTICS
235void LinkBuffer::dumpLinkStatistics(void* code, size_t initializeSize, size_t finalSize)
236{
237 static unsigned linkCount = 0;
238 static unsigned totalInitialSize = 0;
239 static unsigned totalFinalSize = 0;
240 linkCount++;
241 totalInitialSize += initialSize;
242 totalFinalSize += finalSize;
243 dataLogF("link %p: orig %u, compact %u (delta %u, %.2f%%)\n",
244 code, static_cast<unsigned>(initialSize), static_cast<unsigned>(finalSize),
245 static_cast<unsigned>(initialSize - finalSize),
246 100.0 * (initialSize - finalSize) / initialSize);
247 dataLogF("\ttotal %u: orig %u, compact %u (delta %u, %.2f%%)\n",
248 linkCount, totalInitialSize, totalFinalSize, totalInitialSize - totalFinalSize,
249 100.0 * (totalInitialSize - totalFinalSize) / totalInitialSize);
250}
251#endif
252
253#if DUMP_CODE
254void LinkBuffer::dumpCode(void* code, size_t size)
255{
256#if CPU(ARM_THUMB2)
257 // Dump the generated code in an asm file format that can be assembled and then disassembled
258 // for debugging purposes. For example, save this output as jit.s:
259 // gcc -arch armv7 -c jit.s
260 // otool -tv jit.o
261 static unsigned codeCount = 0;
262 unsigned short* tcode = static_cast<unsigned short*>(code);
263 size_t tsize = size / sizeof(short);
264 char nameBuf[128];
265 snprintf(nameBuf, sizeof(nameBuf), "_jsc_jit%u", codeCount++);
266 dataLogF("\t.syntax unified\n"
267 "\t.section\t__TEXT,__text,regular,pure_instructions\n"
268 "\t.globl\t%s\n"
269 "\t.align 2\n"
270 "\t.code 16\n"
271 "\t.thumb_func\t%s\n"
272 "# %p\n"
273 "%s:\n", nameBuf, nameBuf, code, nameBuf);
274
275 for (unsigned i = 0; i < tsize; i++)
276 dataLogF("\t.short\t0x%x\n", tcode[i]);
277#elif CPU(ARM_TRADITIONAL)
278 // gcc -c jit.s
279 // objdump -D jit.o
280 static unsigned codeCount = 0;
281 unsigned int* tcode = static_cast<unsigned int*>(code);
282 size_t tsize = size / sizeof(unsigned int);
283 char nameBuf[128];
284 snprintf(nameBuf, sizeof(nameBuf), "_jsc_jit%u", codeCount++);
285 dataLogF("\t.globl\t%s\n"
286 "\t.align 4\n"
287 "\t.code 32\n"
288 "\t.text\n"
289 "# %p\n"
290 "%s:\n", nameBuf, code, nameBuf);
291
292 for (unsigned i = 0; i < tsize; i++)
293 dataLogF("\t.long\t0x%x\n", tcode[i]);
294#endif
295}
296#endif
297
298} // namespace JSC
299
300#endif // ENABLE(ASSEMBLER)
301
302