assembler/LinkBuffer.h

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