assembler/LinkBuffer.h

   1 /*
   2  * Copyright (C) 2009, 2010, 2012-2015 Apple Inc. All rights reserved.
   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 #ifndef LinkBuffer_h
  27 #define LinkBuffer_h
  28
  29 #if ENABLE(ASSEMBLER)
  30
  31 #define DUMP_LINK_STATISTICS 0
  32 #define DUMP_CODE 0
  33
  34 #define GLOBAL_THUNK_ID reinterpret_cast<void*>(static_cast<intptr_t>(-1))
  35 #define REGEXP_CODE_ID reinterpret_cast<void*>(static_cast<intptr_t>(-2))
  36 #define CSS_CODE_ID reinterpret_cast<void*>(static_cast<intptr_t>(-3))
  37
  38 #include "JITCompilationEffort.h"
  39 #include "MacroAssembler.h"
  40 #include <wtf/DataLog.h>
  41 #include <wtf/FastMalloc.h>
  42 #include <wtf/Noncopyable.h>
  43
  44 namespace JSC {
  45
  46 class CodeBlock;
  47 class VM;
  48
  49 // LinkBuffer:
  50 //
  51 // This class assists in linking code generated by the macro assembler, once code generation
  52 // has been completed, and the code has been copied to is final location in memory.  At this
  53 // time pointers to labels within the code may be resolved, and relative offsets to external
  54 // addresses may be fixed.
  55 //
  56 // Specifically:
  57 //   * Jump objects may be linked to external targets,
  58 //   * The address of Jump objects may taken, such that it can later be relinked.
  59 //   * The return address of a Call may be acquired.
  60 //   * The address of a Label pointing into the code may be resolved.
  61 //   * The value referenced by a DataLabel may be set.
  62 //
  63 class LinkBuffer {
  64     WTF_MAKE_NONCOPYABLE(LinkBuffer); WTF_MAKE_FAST_ALLOCATED;
  65
  66     typedef MacroAssemblerCodeRef CodeRef;
  67     typedef MacroAssemblerCodePtr CodePtr;
  68     typedef MacroAssembler::Label Label;
  69     typedef MacroAssembler::Jump Jump;
  70     typedef MacroAssembler::PatchableJump PatchableJump;
  71     typedef MacroAssembler::JumpList JumpList;
  72     typedef MacroAssembler::Call Call;
  73     typedef MacroAssembler::DataLabelCompact DataLabelCompact;
  74     typedef MacroAssembler::DataLabel32 DataLabel32;
  75     typedef MacroAssembler::DataLabelPtr DataLabelPtr;
  76     typedef MacroAssembler::ConvertibleLoadLabel ConvertibleLoadLabel;
  77 #if ENABLE(BRANCH_COMPACTION)
  78     typedef MacroAssembler::LinkRecord LinkRecord;
  79     typedef MacroAssembler::JumpLinkType JumpLinkType;
  80 #endif
  81
  82 public:
  83     LinkBuffer(VM& vm, MacroAssembler& macroAssembler, void* ownerUID, JITCompilationEffort effort = JITCompilationMustSucceed)
  84         : m_size(0)
  85 #if ENABLE(BRANCH_COMPACTION)
  86         , m_initialSize(0)
  87 #endif
  88         , m_didAllocate(false)
  89         , m_code(0)
  90         , m_vm(&vm)
  91 #ifndef NDEBUG
  92         , m_completed(false)
  93 #endif
  94     {
  95         linkCode(macroAssembler, ownerUID, effort);
  96     }
  97
  98     LinkBuffer(VM& vm, MacroAssembler& macroAssembler, void* code, size_t size)
  99         : m_size(size)
 100 #if ENABLE(BRANCH_COMPACTION)
 101         , m_initialSize(0)
 102 #endif
 103         , m_didAllocate(false)
 104         , m_code(code)
 105         , m_vm(&vm)
 106 #ifndef NDEBUG
 107         , m_completed(false)
 108 #endif
 109     {
 110         linkCode(macroAssembler, 0, JITCompilationCanFail);
 111     }
 112
 113     ~LinkBuffer()
 114     {
 115     }
 116
 117     bool didFailToAllocate() const
 118     {
 119         return !m_didAllocate;
 120     }
 121
 122     bool isValid() const
 123     {
 124         return !didFailToAllocate();
 125     }
 126
 127     // These methods are used to link or set values at code generation time.
 128
 129     void link(Call call, FunctionPtr function)
 130     {
 131         ASSERT(call.isFlagSet(Call::Linkable));
 132         call.m_label = applyOffset(call.m_label);
 133         MacroAssembler::linkCall(code(), call, function);
 134     }
 135
 136     void link(Call call, CodeLocationLabel label)
 137     {
 138         link(call, FunctionPtr(label.executableAddress()));
 139     }
 140
 141     void link(Jump jump, CodeLocationLabel label)
 142     {
 143         jump.m_label = applyOffset(jump.m_label);
 144         MacroAssembler::linkJump(code(), jump, label);
 145     }
 146
 147     void link(JumpList list, CodeLocationLabel label)
 148     {
 149         for (unsigned i = 0; i < list.m_jumps.size(); ++i)
 150             link(list.m_jumps[i], label);
 151     }
 152
 153     void patch(DataLabelPtr label, void* value)
 154     {
 155         AssemblerLabel target = applyOffset(label.m_label);
 156         MacroAssembler::linkPointer(code(), target, value);
 157     }
 158
 159     void patch(DataLabelPtr label, CodeLocationLabel value)
 160     {
 161         AssemblerLabel target = applyOffset(label.m_label);
 162         MacroAssembler::linkPointer(code(), target, value.executableAddress());
 163     }
 164
 165     // These methods are used to obtain handles to allow the code to be relinked / repatched later.
 166
 167     CodeLocationLabel entrypoint()
 168     {
 169         return CodeLocationLabel(code());
 170     }
 171
 172     CodeLocationCall locationOf(Call call)
 173     {
 174         ASSERT(call.isFlagSet(Call::Linkable));
 175         ASSERT(!call.isFlagSet(Call::Near));
 176         return CodeLocationCall(MacroAssembler::getLinkerAddress(code(), applyOffset(call.m_label)));
 177     }
 178
 179     CodeLocationNearCall locationOfNearCall(Call call)
 180     {
 181         ASSERT(call.isFlagSet(Call::Linkable));
 182         ASSERT(call.isFlagSet(Call::Near));
 183         return CodeLocationNearCall(MacroAssembler::getLinkerAddress(code(), applyOffset(call.m_label)));
 184     }
 185
 186     CodeLocationLabel locationOf(PatchableJump jump)
 187     {
 188         return CodeLocationLabel(MacroAssembler::getLinkerAddress(code(), applyOffset(jump.m_jump.m_label)));
 189     }
 190
 191     CodeLocationLabel locationOf(Label label)
 192     {
 193         return CodeLocationLabel(MacroAssembler::getLinkerAddress(code(), applyOffset(label.m_label)));
 194     }
 195
 196     CodeLocationDataLabelPtr locationOf(DataLabelPtr label)
 197     {
 198         return CodeLocationDataLabelPtr(MacroAssembler::getLinkerAddress(code(), applyOffset(label.m_label)));
 199     }
 200
 201     CodeLocationDataLabel32 locationOf(DataLabel32 label)
 202     {
 203         return CodeLocationDataLabel32(MacroAssembler::getLinkerAddress(code(), applyOffset(label.m_label)));
 204     }
 205
 206     CodeLocationDataLabelCompact locationOf(DataLabelCompact label)
 207     {
 208         return CodeLocationDataLabelCompact(MacroAssembler::getLinkerAddress(code(), applyOffset(label.m_label)));
 209     }
 210
 211     CodeLocationConvertibleLoad locationOf(ConvertibleLoadLabel label)
 212     {
 213         return CodeLocationConvertibleLoad(MacroAssembler::getLinkerAddress(code(), applyOffset(label.m_label)));
 214     }
 215
 216     // This method obtains the return address of the call, given as an offset from
 217     // the start of the code.
 218     unsigned returnAddressOffset(Call call)
 219     {
 220         call.m_label = applyOffset(call.m_label);
 221         return MacroAssembler::getLinkerCallReturnOffset(call);
 222     }
 223
 224     uint32_t offsetOf(Label label)
 225     {
 226         return applyOffset(label.m_label).m_offset;
 227     }
 228
 229     unsigned offsetOf(PatchableJump jump)
 230     {
 231         return applyOffset(jump.m_jump.m_label).m_offset;
 232     }
 233
 234     // Upon completion of all patching 'FINALIZE_CODE()' should be called once to
 235     // complete generation of the code. Alternatively, call
 236     // finalizeCodeWithoutDisassembly() directly if you have your own way of
 237     // displaying disassembly.
 238
 239     JS_EXPORT_PRIVATE CodeRef finalizeCodeWithoutDisassembly();
 240     JS_EXPORT_PRIVATE CodeRef finalizeCodeWithDisassembly(const char* format, ...) WTF_ATTRIBUTE_PRINTF(2, 3);
 241
 242     CodePtr trampolineAt(Label label)
 243     {
 244         return CodePtr(MacroAssembler::AssemblerType_T::getRelocatedAddress(code(), applyOffset(label.m_label)));
 245     }
 246
 247     void* debugAddress()
 248     {
 249         return m_code;
 250     }
 251
 252     // FIXME: this does not account for the AssemblerData size!
 253     size_t size()
 254     {
 255         return m_size;
 256     }
 257
 258     bool wasAlreadyDisassembled() const { return m_alreadyDisassembled; }
 259     void didAlreadyDisassemble() { m_alreadyDisassembled = true; }
 260
 261 private:
 262 #if ENABLE(BRANCH_COMPACTION)
 263     int executableOffsetFor(int location)
 264     {
 265         if (!location)
 266             return 0;
 267         return bitwise_cast<int32_t*>(m_assemblerStorage.buffer())[location / sizeof(int32_t) - 1];
 268     }
 269 #endif
 270
 271     template <typename T> T applyOffset(T src)
 272     {
 273 #if ENABLE(BRANCH_COMPACTION)
 274         src.m_offset -= executableOffsetFor(src.m_offset);
 275 #endif
 276         return src;
 277     }
 278
 279     // Keep this private! - the underlying code should only be obtained externally via finalizeCode().
 280     void* code()
 281     {
 282         return m_code;
 283     }
 284
 285     void allocate(size_t initialSize, void* ownerUID, JITCompilationEffort);
 286     void shrink(size_t newSize);
 287
 288     JS_EXPORT_PRIVATE void linkCode(MacroAssembler&, void* ownerUID, JITCompilationEffort);
 289 #if ENABLE(BRANCH_COMPACTION)
 290     template <typename InstructionType>
 291     void copyCompactAndLinkCode(MacroAssembler&, void* ownerUID, JITCompilationEffort);
 292 #endif
 293
 294     void performFinalization();
 295
 296 #if DUMP_LINK_STATISTICS
 297     static void dumpLinkStatistics(void* code, size_t initialSize, size_t finalSize);
 298 #endif
 299
 300 #if DUMP_CODE
 301     static void dumpCode(void* code, size_t);
 302 #endif
 303
 304     RefPtr<ExecutableMemoryHandle> m_executableMemory;
 305     size_t m_size;
 306 #if ENABLE(BRANCH_COMPACTION)
 307     size_t m_initialSize;
 308     AssemblerData m_assemblerStorage;
 309 #endif
 310     bool m_didAllocate;
 311     void* m_code;
 312     VM* m_vm;
 313 #ifndef NDEBUG
 314     bool m_completed;
 315 #endif
 316     bool m_alreadyDisassembled { false };
 317 };
 318
 319 #define FINALIZE_CODE_IF(condition, linkBufferReference, dataLogFArgumentsForHeading)  \
 320     (UNLIKELY((condition))                                              \
 321      ? ((linkBufferReference).finalizeCodeWithDisassembly dataLogFArgumentsForHeading) \
 322      : (linkBufferReference).finalizeCodeWithoutDisassembly())
 323
 324 bool shouldShowDisassemblyFor(CodeBlock*);
 325
 326 #define FINALIZE_CODE_FOR(codeBlock, linkBufferReference, dataLogFArgumentsForHeading)  \
 327     FINALIZE_CODE_IF(shouldShowDisassemblyFor(codeBlock) || Options::asyncDisassembly(), linkBufferReference, dataLogFArgumentsForHeading)
 328
 329 // Use this to finalize code, like so:
 330 //
 331 // CodeRef code = FINALIZE_CODE(linkBuffer, ("my super thingy number %d", number));
 332 //
 333 // Which, in disassembly mode, will print:
 334 //
 335 // Generated JIT code for my super thingy number 42:
 336 //     Code at [0x123456, 0x234567]:
 337 //         0x123456: mov $0, 0
 338 //         0x12345a: ret
 339 //
 340 // ... and so on.
 341 //
 342 // Note that the dataLogFArgumentsForHeading are only evaluated when showDisassembly
 343 // is true, so you can hide expensive disassembly-only computations inside there.
 344
 345 #define FINALIZE_CODE(linkBufferReference, dataLogFArgumentsForHeading)  \
 346     FINALIZE_CODE_IF(JSC::Options::asyncDisassembly() || JSC::Options::showDisassembly(), linkBufferReference, dataLogFArgumentsForHeading)
 347
 348 #define FINALIZE_DFG_CODE(linkBufferReference, dataLogFArgumentsForHeading)  \
 349     FINALIZE_CODE_IF(JSC::Options::asyncDisassembly() || JSC::Options::showDisassembly() || Options::showDFGDisassembly(), linkBufferReference, dataLogFArgumentsForHeading)
 350
 351 } // namespace JSC
 352
 353 #endif // ENABLE(ASSEMBLER)
 354
 355 #endif // LinkBuffer_h