Source/JavaScriptCore/jit/JITPropertyAccess.cpp

   1 /*
   2  * Copyright (C) 2008, 2009 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 #include "config.h"
  27
  28 #if ENABLE(JIT)
  29 #include "JIT.h"
  30
  31 #include "CodeBlock.h"
  32 #include "GCAwareJITStubRoutine.h"
  33 #include "GetterSetter.h"
  34 #include "Interpreter.h"
  35 #include "JITInlineMethods.h"
  36 #include "JITStubCall.h"
  37 #include "JSArray.h"
  38 #include "JSFunction.h"
  39 #include "JSPropertyNameIterator.h"
  40 #include "JSVariableObject.h"
  41 #include "LinkBuffer.h"
  42 #include "RepatchBuffer.h"
  43 #include "ResultType.h"
  44 #include "SamplingTool.h"
  45
  46 #ifndef NDEBUG
  47 #include <stdio.h>
  48 #endif
  49
  50 using namespace std;
  51
  52 namespace JSC {
  53 #if USE(JSVALUE64)
  54
  55 JIT::CodeRef JIT::stringGetByValStubGenerator(JSGlobalData* globalData)
  56 {
  57     JSInterfaceJIT jit;
  58     JumpList failures;
  59     failures.append(jit.branchPtr(NotEqual, Address(regT0, JSCell::structureOffset()), TrustedImmPtr(globalData->stringStructure.get())));
  60
  61     // Load string length to regT2, and start the process of loading the data pointer into regT0
  62     jit.load32(Address(regT0, ThunkHelpers::jsStringLengthOffset()), regT2);
  63     jit.loadPtr(Address(regT0, ThunkHelpers::jsStringValueOffset()), regT0);
  64     failures.append(jit.branchTest32(Zero, regT0));
  65
  66     // Do an unsigned compare to simultaneously filter negative indices as well as indices that are too large
  67     failures.append(jit.branch32(AboveOrEqual, regT1, regT2));
  68
  69     // Load the character
  70     JumpList is16Bit;
  71     JumpList cont8Bit;
  72     // Load the string flags
  73     jit.loadPtr(Address(regT0, ThunkHelpers::stringImplFlagsOffset()), regT2);
  74     jit.loadPtr(Address(regT0, ThunkHelpers::stringImplDataOffset()), regT0);
  75     is16Bit.append(jit.branchTest32(Zero, regT2, TrustedImm32(ThunkHelpers::stringImpl8BitFlag())));
  76     jit.load8(BaseIndex(regT0, regT1, TimesOne, 0), regT0);
  77     cont8Bit.append(jit.jump());
  78     is16Bit.link(&jit);
  79     jit.load16(BaseIndex(regT0, regT1, TimesTwo, 0), regT0);
  80     cont8Bit.link(&jit);
  81
  82     failures.append(jit.branch32(AboveOrEqual, regT0, TrustedImm32(0x100)));
  83     jit.move(TrustedImmPtr(globalData->smallStrings.singleCharacterStrings()), regT1);
  84     jit.loadPtr(BaseIndex(regT1, regT0, ScalePtr, 0), regT0);
  85     jit.ret();
  86
  87     failures.link(&jit);
  88     jit.move(TrustedImm32(0), regT0);
  89     jit.ret();
  90
  91     LinkBuffer patchBuffer(*globalData, &jit, GLOBAL_THUNK_ID);
  92     return FINALIZE_CODE(patchBuffer, ("String get_by_val stub"));
  93 }
  94
  95 void JIT::emit_op_get_by_val(Instruction* currentInstruction)
  96 {
  97     unsigned dst = currentInstruction[1].u.operand;
  98     unsigned base = currentInstruction[2].u.operand;
  99     unsigned property = currentInstruction[3].u.operand;
 100
 101     emitGetVirtualRegisters(base, regT0, property, regT1);
 102     emitJumpSlowCaseIfNotImmediateInteger(regT1);
 103
 104     // This is technically incorrect - we're zero-extending an int32.  On the hot path this doesn't matter.
 105     // We check the value as if it was a uint32 against the m_vectorLength - which will always fail if
 106     // number was signed since m_vectorLength is always less than intmax (since the total allocation
 107     // size is always less than 4Gb).  As such zero extending wil have been correct (and extending the value
 108     // to 64-bits is necessary since it's used in the address calculation.  We zero extend rather than sign
 109     // extending since it makes it easier to re-tag the value in the slow case.
 110     zeroExtend32ToPtr(regT1, regT1);
 111
 112     emitJumpSlowCaseIfNotJSCell(regT0, base);
 113     addSlowCase(branchPtr(NotEqual, Address(regT0, JSCell::classInfoOffset()), TrustedImmPtr(&JSArray::s_info)));
 114
 115     loadPtr(Address(regT0, JSArray::storageOffset()), regT2);
 116     addSlowCase(branch32(AboveOrEqual, regT1, Address(regT0, JSArray::vectorLengthOffset())));
 117
 118     loadPtr(BaseIndex(regT2, regT1, ScalePtr, OBJECT_OFFSETOF(ArrayStorage, m_vector[0])), regT0);
 119     addSlowCase(branchTestPtr(Zero, regT0));
 120
 121     emitValueProfilingSite();
 122     emitPutVirtualRegister(dst);
 123 }
 124
 125 void JIT::emitSlow_op_get_by_val(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
 126 {
 127     unsigned dst = currentInstruction[1].u.operand;
 128     unsigned base = currentInstruction[2].u.operand;
 129     unsigned property = currentInstruction[3].u.operand;
 130
 131     linkSlowCase(iter); // property int32 check
 132     linkSlowCaseIfNotJSCell(iter, base); // base cell check
 133     Jump nonCell = jump();
 134     linkSlowCase(iter); // base array check
 135     Jump notString = branchPtr(NotEqual, Address(regT0, JSCell::structureOffset()), TrustedImmPtr(m_globalData->stringStructure.get()));
 136     emitNakedCall(CodeLocationLabel(m_globalData->getCTIStub(stringGetByValStubGenerator).code()));
 137     Jump failed = branchTestPtr(Zero, regT0);
 138     emitPutVirtualRegister(dst, regT0);
 139     emitJumpSlowToHot(jump(), OPCODE_LENGTH(op_get_by_val));
 140     failed.link(this);
 141     notString.link(this);
 142     nonCell.link(this);
 143
 144     linkSlowCase(iter); // vector length check
 145     linkSlowCase(iter); // empty value
 146
 147     JITStubCall stubCall(this, cti_op_get_by_val);
 148     stubCall.addArgument(base, regT2);
 149     stubCall.addArgument(property, regT2);
 150     stubCall.call(dst);
 151
 152     emitValueProfilingSite();
 153 }
 154
 155 void JIT::compileGetDirectOffset(RegisterID base, RegisterID result, RegisterID offset, RegisterID scratch, FinalObjectMode finalObjectMode)
 156 {
 157     ASSERT(sizeof(JSValue) == 8);
 158
 159     if (finalObjectMode == MayBeFinal) {
 160         Jump isInline = branch32(LessThan, offset, TrustedImm32(inlineStorageCapacity));
 161         loadPtr(Address(base, JSObject::offsetOfOutOfLineStorage()), scratch);
 162         neg32(offset);
 163         Jump done = jump();
 164         isInline.link(this);
 165         addPtr(TrustedImm32(JSObject::offsetOfInlineStorage() - (inlineStorageCapacity - 2) * sizeof(EncodedJSValue)), base, scratch);
 166         done.link(this);
 167     } else {
 168 #if !ASSERT_DISABLED
 169         Jump isOutOfLine = branch32(GreaterThanOrEqual, offset, TrustedImm32(inlineStorageCapacity));
 170         breakpoint();
 171         isOutOfLine.link(this);
 172 #endif
 173         loadPtr(Address(base, JSObject::offsetOfOutOfLineStorage()), scratch);
 174         neg32(offset);
 175     }
 176     signExtend32ToPtr(offset, offset);
 177     loadPtr(BaseIndex(scratch, offset, ScalePtr, (inlineStorageCapacity - 2) * static_cast<ptrdiff_t>(sizeof(JSValue))), result);
 178 }
 179
 180 void JIT::emit_op_get_by_pname(Instruction* currentInstruction)
 181 {
 182     unsigned dst = currentInstruction[1].u.operand;
 183     unsigned base = currentInstruction[2].u.operand;
 184     unsigned property = currentInstruction[3].u.operand;
 185     unsigned expected = currentInstruction[4].u.operand;
 186     unsigned iter = currentInstruction[5].u.operand;
 187     unsigned i = currentInstruction[6].u.operand;
 188
 189     emitGetVirtualRegister(property, regT0);
 190     addSlowCase(branchPtr(NotEqual, regT0, addressFor(expected)));
 191     emitGetVirtualRegisters(base, regT0, iter, regT1);
 192     emitJumpSlowCaseIfNotJSCell(regT0, base);
 193
 194     // Test base's structure
 195     loadPtr(Address(regT0, JSCell::structureOffset()), regT2);
 196     addSlowCase(branchPtr(NotEqual, regT2, Address(regT1, OBJECT_OFFSETOF(JSPropertyNameIterator, m_cachedStructure))));
 197     load32(addressFor(i), regT3);
 198     sub32(TrustedImm32(1), regT3);
 199     addSlowCase(branch32(AboveOrEqual, regT3, Address(regT1, OBJECT_OFFSETOF(JSPropertyNameIterator, m_numCacheableSlots))));
 200     add32(Address(regT1, OBJECT_OFFSETOF(JSPropertyNameIterator, m_offsetBase)), regT3);
 201     compileGetDirectOffset(regT0, regT0, regT3, regT1);
 202
 203     emitPutVirtualRegister(dst, regT0);
 204 }
 205
 206 void JIT::emitSlow_op_get_by_pname(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
 207 {
 208     unsigned dst = currentInstruction[1].u.operand;
 209     unsigned base = currentInstruction[2].u.operand;
 210     unsigned property = currentInstruction[3].u.operand;
 211
 212     linkSlowCase(iter);
 213     linkSlowCaseIfNotJSCell(iter, base);
 214     linkSlowCase(iter);
 215     linkSlowCase(iter);
 216
 217     JITStubCall stubCall(this, cti_op_get_by_val);
 218     stubCall.addArgument(base, regT2);
 219     stubCall.addArgument(property, regT2);
 220     stubCall.call(dst);
 221 }
 222
 223 void JIT::emit_op_put_by_val(Instruction* currentInstruction)
 224 {
 225     unsigned base = currentInstruction[1].u.operand;
 226     unsigned property = currentInstruction[2].u.operand;
 227     unsigned value = currentInstruction[3].u.operand;
 228
 229     emitGetVirtualRegisters(base, regT0, property, regT1);
 230     emitJumpSlowCaseIfNotImmediateInteger(regT1);
 231     // See comment in op_get_by_val.
 232     zeroExtend32ToPtr(regT1, regT1);
 233     emitJumpSlowCaseIfNotJSCell(regT0, base);
 234     addSlowCase(branchPtr(NotEqual, Address(regT0, JSCell::classInfoOffset()), TrustedImmPtr(&JSArray::s_info)));
 235     addSlowCase(branch32(AboveOrEqual, regT1, Address(regT0, JSArray::vectorLengthOffset())));
 236
 237     loadPtr(Address(regT0, JSArray::storageOffset()), regT2);
 238     Jump empty = branchTestPtr(Zero, BaseIndex(regT2, regT1, ScalePtr, OBJECT_OFFSETOF(ArrayStorage, m_vector[0])));
 239
 240     Label storeResult(this);
 241     emitGetVirtualRegister(value, regT3);
 242     storePtr(regT3, BaseIndex(regT2, regT1, ScalePtr, OBJECT_OFFSETOF(ArrayStorage, m_vector[0])));
 243     Jump end = jump();
 244
 245     empty.link(this);
 246     add32(TrustedImm32(1), Address(regT2, OBJECT_OFFSETOF(ArrayStorage, m_numValuesInVector)));
 247     branch32(Below, regT1, Address(regT2, OBJECT_OFFSETOF(ArrayStorage, m_length))).linkTo(storeResult, this);
 248
 249     add32(TrustedImm32(1), regT1);
 250     store32(regT1, Address(regT2, OBJECT_OFFSETOF(ArrayStorage, m_length)));
 251     sub32(TrustedImm32(1), regT1);
 252     jump().linkTo(storeResult, this);
 253
 254     end.link(this);
 255
 256     emitWriteBarrier(regT0, regT3, regT1, regT3, ShouldFilterImmediates, WriteBarrierForPropertyAccess);
 257 }
 258
 259 void JIT::emitSlow_op_put_by_val(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
 260 {
 261     unsigned base = currentInstruction[1].u.operand;
 262     unsigned property = currentInstruction[2].u.operand;
 263     unsigned value = currentInstruction[3].u.operand;
 264
 265     linkSlowCase(iter); // property int32 check
 266     linkSlowCaseIfNotJSCell(iter, base); // base cell check
 267     linkSlowCase(iter); // base not array check
 268     linkSlowCase(iter); // in vector check
 269
 270     JITStubCall stubPutByValCall(this, cti_op_put_by_val);
 271     stubPutByValCall.addArgument(regT0);
 272     stubPutByValCall.addArgument(property, regT2);
 273     stubPutByValCall.addArgument(value, regT2);
 274     stubPutByValCall.call();
 275 }
 276
 277 void JIT::emit_op_put_by_index(Instruction* currentInstruction)
 278 {
 279     JITStubCall stubCall(this, cti_op_put_by_index);
 280     stubCall.addArgument(currentInstruction[1].u.operand, regT2);
 281     stubCall.addArgument(TrustedImm32(currentInstruction[2].u.operand));
 282     stubCall.addArgument(currentInstruction[3].u.operand, regT2);
 283     stubCall.call();
 284 }
 285
 286 void JIT::emit_op_put_getter_setter(Instruction* currentInstruction)
 287 {
 288     JITStubCall stubCall(this, cti_op_put_getter_setter);
 289     stubCall.addArgument(currentInstruction[1].u.operand, regT2);
 290     stubCall.addArgument(TrustedImmPtr(&m_codeBlock->identifier(currentInstruction[2].u.operand)));
 291     stubCall.addArgument(currentInstruction[3].u.operand, regT2);
 292     stubCall.addArgument(currentInstruction[4].u.operand, regT2);
 293     stubCall.call();
 294 }
 295
 296 void JIT::emit_op_del_by_id(Instruction* currentInstruction)
 297 {
 298     JITStubCall stubCall(this, cti_op_del_by_id);
 299     stubCall.addArgument(currentInstruction[2].u.operand, regT2);
 300     stubCall.addArgument(TrustedImmPtr(&m_codeBlock->identifier(currentInstruction[3].u.operand)));
 301     stubCall.call(currentInstruction[1].u.operand);
 302 }
 303
 304 void JIT::emit_op_method_check(Instruction* currentInstruction)
 305 {
 306     // Assert that the following instruction is a get_by_id.
 307     ASSERT(m_interpreter->getOpcodeID((currentInstruction + OPCODE_LENGTH(op_method_check))->u.opcode) == op_get_by_id
 308         || m_interpreter->getOpcodeID((currentInstruction + OPCODE_LENGTH(op_method_check))->u.opcode) == op_get_by_id_out_of_line);
 309
 310     currentInstruction += OPCODE_LENGTH(op_method_check);
 311     unsigned resultVReg = currentInstruction[1].u.operand;
 312     unsigned baseVReg = currentInstruction[2].u.operand;
 313     Identifier* ident = &(m_codeBlock->identifier(currentInstruction[3].u.operand));
 314
 315     emitGetVirtualRegister(baseVReg, regT0);
 316
 317     // Do the method check - check the object & its prototype's structure inline (this is the common case).
 318     m_methodCallCompilationInfo.append(MethodCallCompilationInfo(m_bytecodeOffset, m_propertyAccessCompilationInfo.size()));
 319     MethodCallCompilationInfo& info = m_methodCallCompilationInfo.last();
 320
 321     Jump notCell = emitJumpIfNotJSCell(regT0);
 322
 323     BEGIN_UNINTERRUPTED_SEQUENCE(sequenceMethodCheck);
 324
 325     Jump structureCheck = branchPtrWithPatch(NotEqual, Address(regT0, JSCell::structureOffset()), info.structureToCompare, TrustedImmPtr(reinterpret_cast<void*>(patchGetByIdDefaultStructure)));
 326     DataLabelPtr protoStructureToCompare, protoObj = moveWithPatch(TrustedImmPtr(0), regT1);
 327     Jump protoStructureCheck = branchPtrWithPatch(NotEqual, Address(regT1, JSCell::structureOffset()), protoStructureToCompare, TrustedImmPtr(reinterpret_cast<void*>(patchGetByIdDefaultStructure)));
 328
 329     // This will be relinked to load the function without doing a load.
 330     DataLabelPtr putFunction = moveWithPatch(TrustedImmPtr(0), regT0);
 331
 332     END_UNINTERRUPTED_SEQUENCE(sequenceMethodCheck);
 333
 334     Jump match = jump();
 335
 336     // Link the failure cases here.
 337     notCell.link(this);
 338     structureCheck.link(this);
 339     protoStructureCheck.link(this);
 340
 341     // Do a regular(ish) get_by_id (the slow case will be link to
 342     // cti_op_get_by_id_method_check instead of cti_op_get_by_id.
 343     compileGetByIdHotPath(baseVReg, ident);
 344
 345     match.link(this);
 346     emitValueProfilingSite(m_bytecodeOffset + OPCODE_LENGTH(op_method_check));
 347     emitPutVirtualRegister(resultVReg);
 348
 349     // We've already generated the following get_by_id, so make sure it's skipped over.
 350     m_bytecodeOffset += OPCODE_LENGTH(op_get_by_id);
 351
 352     m_propertyAccessCompilationInfo.last().addMethodCheckInfo(info.structureToCompare, protoObj, protoStructureToCompare, putFunction);
 353 }
 354
 355 void JIT::emitSlow_op_method_check(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
 356 {
 357     currentInstruction += OPCODE_LENGTH(op_method_check);
 358     unsigned resultVReg = currentInstruction[1].u.operand;
 359     unsigned baseVReg = currentInstruction[2].u.operand;
 360     Identifier* ident = &(m_codeBlock->identifier(currentInstruction[3].u.operand));
 361
 362     compileGetByIdSlowCase(resultVReg, baseVReg, ident, iter, true);
 363     emitValueProfilingSite(m_bytecodeOffset + OPCODE_LENGTH(op_method_check));
 364
 365     // We've already generated the following get_by_id, so make sure it's skipped over.
 366     m_bytecodeOffset += OPCODE_LENGTH(op_get_by_id);
 367 }
 368
 369 void JIT::emit_op_get_by_id(Instruction* currentInstruction)
 370 {
 371     unsigned resultVReg = currentInstruction[1].u.operand;
 372     unsigned baseVReg = currentInstruction[2].u.operand;
 373     Identifier* ident = &(m_codeBlock->identifier(currentInstruction[3].u.operand));
 374
 375     emitGetVirtualRegister(baseVReg, regT0);
 376     compileGetByIdHotPath(baseVReg, ident);
 377     emitValueProfilingSite();
 378     emitPutVirtualRegister(resultVReg);
 379 }
 380
 381 void JIT::compileGetByIdHotPath(int baseVReg, Identifier*)
 382 {
 383     // As for put_by_id, get_by_id requires the offset of the Structure and the offset of the access to be patched.
 384     // Additionally, for get_by_id we need patch the offset of the branch to the slow case (we patch this to jump
 385     // to array-length / prototype access tranpolines, and finally we also the the property-map access offset as a label
 386     // to jump back to if one of these trampolies finds a match.
 387
 388     emitJumpSlowCaseIfNotJSCell(regT0, baseVReg);
 389
 390     BEGIN_UNINTERRUPTED_SEQUENCE(sequenceGetByIdHotPath);
 391
 392     Label hotPathBegin(this);
 393
 394     DataLabelPtr structureToCompare;
 395     PatchableJump structureCheck = patchableBranchPtrWithPatch(NotEqual, Address(regT0, JSCell::structureOffset()), structureToCompare, TrustedImmPtr(reinterpret_cast<void*>(patchGetByIdDefaultStructure)));
 396     addSlowCase(structureCheck);
 397
 398     ConvertibleLoadLabel propertyStorageLoad = convertibleLoadPtr(Address(regT0, JSObject::offsetOfOutOfLineStorage()), regT0);
 399     DataLabelCompact displacementLabel = loadPtrWithCompactAddressOffsetPatch(Address(regT0, patchGetByIdDefaultOffset), regT0);
 400
 401     Label putResult(this);
 402
 403     END_UNINTERRUPTED_SEQUENCE(sequenceGetByIdHotPath);
 404
 405     m_propertyAccessCompilationInfo.append(PropertyStubCompilationInfo(PropertyStubGetById, m_bytecodeOffset, hotPathBegin, structureToCompare, structureCheck, propertyStorageLoad, displacementLabel, putResult));
 406 }
 407
 408 void JIT::emitSlow_op_get_by_id(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
 409 {
 410     unsigned resultVReg = currentInstruction[1].u.operand;
 411     unsigned baseVReg = currentInstruction[2].u.operand;
 412     Identifier* ident = &(m_codeBlock->identifier(currentInstruction[3].u.operand));
 413
 414     compileGetByIdSlowCase(resultVReg, baseVReg, ident, iter, false);
 415     emitValueProfilingSite();
 416 }
 417
 418 void JIT::compileGetByIdSlowCase(int resultVReg, int baseVReg, Identifier* ident, Vector<SlowCaseEntry>::iterator& iter, bool isMethodCheck)
 419 {
 420     // As for the hot path of get_by_id, above, we ensure that we can use an architecture specific offset
 421     // so that we only need track one pointer into the slow case code - we track a pointer to the location
 422     // of the call (which we can use to look up the patch information), but should a array-length or
 423     // prototype access trampoline fail we want to bail out back to here.  To do so we can subtract back
 424     // the distance from the call to the head of the slow case.
 425
 426     linkSlowCaseIfNotJSCell(iter, baseVReg);
 427     linkSlowCase(iter);
 428
 429     BEGIN_UNINTERRUPTED_SEQUENCE(sequenceGetByIdSlowCase);
 430
 431     Label coldPathBegin(this);
 432     JITStubCall stubCall(this, isMethodCheck ? cti_op_get_by_id_method_check : cti_op_get_by_id);
 433     stubCall.addArgument(regT0);
 434     stubCall.addArgument(TrustedImmPtr(ident));
 435     Call call = stubCall.call(resultVReg);
 436
 437     END_UNINTERRUPTED_SEQUENCE(sequenceGetByIdSlowCase);
 438
 439     // Track the location of the call; this will be used to recover patch information.
 440     m_propertyAccessCompilationInfo[m_propertyAccessInstructionIndex++].slowCaseInfo(PropertyStubGetById, coldPathBegin, call);
 441 }
 442
 443 void JIT::emit_op_put_by_id(Instruction* currentInstruction)
 444 {
 445     unsigned baseVReg = currentInstruction[1].u.operand;
 446     unsigned valueVReg = currentInstruction[3].u.operand;
 447
 448     // In order to be able to patch both the Structure, and the object offset, we store one pointer,
 449     // to just after the arguments have been loaded into registers 'hotPathBegin', and we generate code
 450     // such that the Structure & offset are always at the same distance from this.
 451
 452     emitGetVirtualRegisters(baseVReg, regT0, valueVReg, regT1);
 453
 454     // Jump to a slow case if either the base object is an immediate, or if the Structure does not match.
 455     emitJumpSlowCaseIfNotJSCell(regT0, baseVReg);
 456
 457     BEGIN_UNINTERRUPTED_SEQUENCE(sequencePutById);
 458
 459     Label hotPathBegin(this);
 460
 461     // It is important that the following instruction plants a 32bit immediate, in order that it can be patched over.
 462     DataLabelPtr structureToCompare;
 463     addSlowCase(branchPtrWithPatch(NotEqual, Address(regT0, JSCell::structureOffset()), structureToCompare, TrustedImmPtr(reinterpret_cast<void*>(patchGetByIdDefaultStructure))));
 464
 465     ConvertibleLoadLabel propertyStorageLoad = convertibleLoadPtr(Address(regT0, JSObject::offsetOfOutOfLineStorage()), regT2);
 466     DataLabel32 displacementLabel = storePtrWithAddressOffsetPatch(regT1, Address(regT2, patchPutByIdDefaultOffset));
 467
 468     END_UNINTERRUPTED_SEQUENCE(sequencePutById);
 469
 470     emitWriteBarrier(regT0, regT1, regT2, regT3, ShouldFilterImmediates, WriteBarrierForPropertyAccess);
 471
 472     m_propertyAccessCompilationInfo.append(PropertyStubCompilationInfo(PropertyStubPutById, m_bytecodeOffset, hotPathBegin, structureToCompare, propertyStorageLoad, displacementLabel));
 473 }
 474
 475 void JIT::emitSlow_op_put_by_id(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
 476 {
 477     unsigned baseVReg = currentInstruction[1].u.operand;
 478     Identifier* ident = &(m_codeBlock->identifier(currentInstruction[2].u.operand));
 479     unsigned direct = currentInstruction[8].u.operand;
 480
 481     linkSlowCaseIfNotJSCell(iter, baseVReg);
 482     linkSlowCase(iter);
 483
 484     JITStubCall stubCall(this, direct ? cti_op_put_by_id_direct : cti_op_put_by_id);
 485     stubCall.addArgument(regT0);
 486     stubCall.addArgument(TrustedImmPtr(ident));
 487     stubCall.addArgument(regT1);
 488     Call call = stubCall.call();
 489
 490     // Track the location of the call; this will be used to recover patch information.
 491     m_propertyAccessCompilationInfo[m_propertyAccessInstructionIndex++].slowCaseInfo(PropertyStubPutById, call);
 492 }
 493
 494 // Compile a store into an object's property storage.  May overwrite the
 495 // value in objectReg.
 496 void JIT::compilePutDirectOffset(RegisterID base, RegisterID value, PropertyOffset cachedOffset)
 497 {
 498     if (isInlineOffset(cachedOffset)) {
 499         storePtr(value, Address(base, JSObject::offsetOfInlineStorage() + sizeof(JSValue) * offsetInInlineStorage(cachedOffset)));
 500         return;
 501     }
 502
 503     loadPtr(Address(base, JSObject::offsetOfOutOfLineStorage()), base);
 504     storePtr(value, Address(base, sizeof(JSValue) * offsetInOutOfLineStorage(cachedOffset)));
 505 }
 506
 507 // Compile a load from an object's property storage.  May overwrite base.
 508 void JIT::compileGetDirectOffset(RegisterID base, RegisterID result, PropertyOffset cachedOffset)
 509 {
 510     if (isInlineOffset(cachedOffset)) {
 511         loadPtr(Address(base, JSObject::offsetOfInlineStorage() + sizeof(JSValue) * offsetInInlineStorage(cachedOffset)), result);
 512         return;
 513     }
 514
 515     loadPtr(Address(base, JSObject::offsetOfOutOfLineStorage()), result);
 516     loadPtr(Address(result, sizeof(JSValue) * offsetInOutOfLineStorage(cachedOffset)), result);
 517 }
 518
 519 void JIT::compileGetDirectOffset(JSObject* base, RegisterID result, PropertyOffset cachedOffset)
 520 {
 521     if (isInlineOffset(cachedOffset)) {
 522         loadPtr(base->locationForOffset(cachedOffset), result);
 523         return;
 524     }
 525
 526     loadPtr(base->addressOfOutOfLineStorage(), result);
 527     loadPtr(Address(result, offsetInOutOfLineStorage(cachedOffset) * sizeof(WriteBarrier<Unknown>)), result);
 528 }
 529
 530 void JIT::privateCompilePutByIdTransition(StructureStubInfo* stubInfo, Structure* oldStructure, Structure* newStructure, PropertyOffset cachedOffset, StructureChain* chain, ReturnAddressPtr returnAddress, bool direct)
 531 {
 532     JumpList failureCases;
 533     // Check eax is an object of the right Structure.
 534     failureCases.append(emitJumpIfNotJSCell(regT0));
 535     failureCases.append(branchPtr(NotEqual, Address(regT0, JSCell::structureOffset()), TrustedImmPtr(oldStructure)));
 536
 537     testPrototype(oldStructure->storedPrototype(), failureCases);
 538
 539     ASSERT(oldStructure->storedPrototype().isNull() || oldStructure->storedPrototype().asCell()->structure() == chain->head()->get());
 540
 541     // ecx = baseObject->m_structure
 542     if (!direct) {
 543         for (WriteBarrier<Structure>* it = chain->head(); *it; ++it) {
 544             ASSERT((*it)->storedPrototype().isNull() || (*it)->storedPrototype().asCell()->structure() == it[1].get());
 545             testPrototype((*it)->storedPrototype(), failureCases);
 546         }
 547     }
 548
 549     // If we succeed in all of our checks, and the code was optimizable, then make sure we
 550     // decrement the rare case counter.
 551 #if ENABLE(VALUE_PROFILER)
 552     if (m_codeBlock->canCompileWithDFG() >= DFG::MayInline) {
 553         sub32(
 554             TrustedImm32(1),
 555             AbsoluteAddress(&m_codeBlock->rareCaseProfileForBytecodeOffset(stubInfo->bytecodeIndex)->m_counter));
 556     }
 557 #endif
 558
 559     // emit a call only if storage realloc is needed
 560     bool willNeedStorageRealloc = oldStructure->outOfLineCapacity() != newStructure->outOfLineCapacity();
 561     if (willNeedStorageRealloc) {
 562         // This trampoline was called to like a JIT stub; before we can can call again we need to
 563         // remove the return address from the stack, to prevent the stack from becoming misaligned.
 564         preserveReturnAddressAfterCall(regT3);
 565
 566         JITStubCall stubCall(this, cti_op_put_by_id_transition_realloc);
 567         stubCall.skipArgument(); // base
 568         stubCall.skipArgument(); // ident
 569         stubCall.skipArgument(); // value
 570         stubCall.addArgument(TrustedImm32(oldStructure->outOfLineCapacity()));
 571         stubCall.addArgument(TrustedImmPtr(newStructure));
 572         stubCall.call(regT0);
 573         emitGetJITStubArg(2, regT1);
 574
 575         restoreReturnAddressBeforeReturn(regT3);
 576     }
 577
 578     // Planting the new structure triggers the write barrier so we need
 579     // an unconditional barrier here.
 580     emitWriteBarrier(regT0, regT1, regT2, regT3, UnconditionalWriteBarrier, WriteBarrierForPropertyAccess);
 581
 582     ASSERT(newStructure->classInfo() == oldStructure->classInfo());
 583     storePtr(TrustedImmPtr(newStructure), Address(regT0, JSCell::structureOffset()));
 584     compilePutDirectOffset(regT0, regT1, cachedOffset);
 585
 586     ret();
 587
 588     ASSERT(!failureCases.empty());
 589     failureCases.link(this);
 590     restoreArgumentReferenceForTrampoline();
 591     Call failureCall = tailRecursiveCall();
 592
 593     LinkBuffer patchBuffer(*m_globalData, this, m_codeBlock);
 594
 595     patchBuffer.link(failureCall, FunctionPtr(direct ? cti_op_put_by_id_direct_fail : cti_op_put_by_id_fail));
 596
 597     if (willNeedStorageRealloc) {
 598         ASSERT(m_calls.size() == 1);
 599         patchBuffer.link(m_calls[0].from, FunctionPtr(cti_op_put_by_id_transition_realloc));
 600     }
 601
 602     stubInfo->stubRoutine = createJITStubRoutine(
 603         FINALIZE_CODE(
 604             patchBuffer,
 605             ("Baseline put_by_id transition for CodeBlock %p, return point %p",
 606              m_codeBlock, returnAddress.value())),
 607         *m_globalData,
 608         m_codeBlock->ownerExecutable(),
 609         willNeedStorageRealloc,
 610         newStructure);
 611     RepatchBuffer repatchBuffer(m_codeBlock);
 612     repatchBuffer.relinkCallerToTrampoline(returnAddress, CodeLocationLabel(stubInfo->stubRoutine->code().code()));
 613 }
 614
 615 void JIT::patchGetByIdSelf(CodeBlock* codeBlock, StructureStubInfo* stubInfo, Structure* structure, PropertyOffset cachedOffset, ReturnAddressPtr returnAddress)
 616 {
 617     RepatchBuffer repatchBuffer(codeBlock);
 618
 619     // We don't want to patch more than once - in future go to cti_op_get_by_id_generic.
 620     // Should probably go to cti_op_get_by_id_fail, but that doesn't do anything interesting right now.
 621     repatchBuffer.relinkCallerToFunction(returnAddress, FunctionPtr(cti_op_get_by_id_self_fail));
 622
 623     // Patch the offset into the propoerty map to load from, then patch the Structure to look for.
 624     repatchBuffer.repatch(stubInfo->hotPathBegin.dataLabelPtrAtOffset(stubInfo->patch.baseline.u.get.structureToCompare), structure);
 625     repatchBuffer.setLoadInstructionIsActive(stubInfo->hotPathBegin.convertibleLoadAtOffset(stubInfo->patch.baseline.u.get.propertyStorageLoad), isOutOfLineOffset(cachedOffset));
 626     repatchBuffer.repatch(stubInfo->hotPathBegin.dataLabelCompactAtOffset(stubInfo->patch.baseline.u.get.displacementLabel), offsetRelativeToPatchedStorage(cachedOffset));
 627 }
 628
 629 void JIT::patchPutByIdReplace(CodeBlock* codeBlock, StructureStubInfo* stubInfo, Structure* structure, PropertyOffset cachedOffset, ReturnAddressPtr returnAddress, bool direct)
 630 {
 631     RepatchBuffer repatchBuffer(codeBlock);
 632
 633     // We don't want to patch more than once - in future go to cti_op_put_by_id_generic.
 634     // Should probably go to cti_op_put_by_id_fail, but that doesn't do anything interesting right now.
 635     repatchBuffer.relinkCallerToFunction(returnAddress, FunctionPtr(direct ? cti_op_put_by_id_direct_generic : cti_op_put_by_id_generic));
 636
 637     // Patch the offset into the propoerty map to load from, then patch the Structure to look for.
 638     repatchBuffer.repatch(stubInfo->hotPathBegin.dataLabelPtrAtOffset(stubInfo->patch.baseline.u.put.structureToCompare), structure);
 639     repatchBuffer.setLoadInstructionIsActive(stubInfo->hotPathBegin.convertibleLoadAtOffset(stubInfo->patch.baseline.u.put.propertyStorageLoad), isOutOfLineOffset(cachedOffset));
 640     repatchBuffer.repatch(stubInfo->hotPathBegin.dataLabel32AtOffset(stubInfo->patch.baseline.u.put.displacementLabel), offsetRelativeToPatchedStorage(cachedOffset));
 641 }
 642
 643 void JIT::privateCompilePatchGetArrayLength(ReturnAddressPtr returnAddress)
 644 {
 645     StructureStubInfo* stubInfo = &m_codeBlock->getStubInfo(returnAddress);
 646
 647     // Check eax is an array
 648     Jump failureCases1 = branchPtr(NotEqual, Address(regT0, JSCell::classInfoOffset()), TrustedImmPtr(&JSArray::s_info));
 649
 650     // Checks out okay! - get the length from the storage
 651     loadPtr(Address(regT0, JSArray::storageOffset()), regT3);
 652     load32(Address(regT3, OBJECT_OFFSETOF(ArrayStorage, m_length)), regT2);
 653     Jump failureCases2 = branch32(LessThan, regT2, TrustedImm32(0));
 654
 655     emitFastArithIntToImmNoCheck(regT2, regT0);
 656     Jump success = jump();
 657
 658     LinkBuffer patchBuffer(*m_globalData, this, m_codeBlock);
 659
 660     // Use the patch information to link the failure cases back to the original slow case routine.
 661     CodeLocationLabel slowCaseBegin = stubInfo->callReturnLocation.labelAtOffset(-stubInfo->patch.baseline.u.get.coldPathBegin);
 662     patchBuffer.link(failureCases1, slowCaseBegin);
 663     patchBuffer.link(failureCases2, slowCaseBegin);
 664
 665     // On success return back to the hot patch code, at a point it will perform the store to dest for us.
 666     patchBuffer.link(success, stubInfo->hotPathBegin.labelAtOffset(stubInfo->patch.baseline.u.get.putResult));
 667
 668     // Track the stub we have created so that it will be deleted later.
 669     stubInfo->stubRoutine = FINALIZE_CODE_FOR_STUB(
 670         patchBuffer,
 671         ("Basline JIT get_by_id array length stub for CodeBlock %p, return point %p",
 672          m_codeBlock, stubInfo->hotPathBegin.labelAtOffset(
 673              stubInfo->patch.baseline.u.get.putResult).executableAddress()));
 674
 675     // Finally patch the jump to slow case back in the hot path to jump here instead.
 676     CodeLocationJump jumpLocation = stubInfo->hotPathBegin.jumpAtOffset(stubInfo->patch.baseline.u.get.structureCheck);
 677     RepatchBuffer repatchBuffer(m_codeBlock);
 678     repatchBuffer.relink(jumpLocation, CodeLocationLabel(stubInfo->stubRoutine->code().code()));
 679
 680     // We don't want to patch more than once - in future go to cti_op_put_by_id_generic.
 681     repatchBuffer.relinkCallerToFunction(returnAddress, FunctionPtr(cti_op_get_by_id_array_fail));
 682 }
 683
 684 void JIT::privateCompileGetByIdProto(StructureStubInfo* stubInfo, Structure* structure, Structure* prototypeStructure, const Identifier& ident, const PropertySlot& slot, PropertyOffset cachedOffset, ReturnAddressPtr returnAddress, CallFrame* callFrame)
 685 {
 686     // The prototype object definitely exists (if this stub exists the CodeBlock is referencing a Structure that is
 687     // referencing the prototype object - let's speculatively load it's table nice and early!)
 688     JSObject* protoObject = asObject(structure->prototypeForLookup(callFrame));
 689
 690     // Check eax is an object of the right Structure.
 691     Jump failureCases1 = checkStructure(regT0, structure);
 692
 693     // Check the prototype object's Structure had not changed.
 694     move(TrustedImmPtr(protoObject), regT3);
 695     Jump failureCases2 = branchPtr(NotEqual, Address(regT3, JSCell::structureOffset()), TrustedImmPtr(prototypeStructure));
 696
 697     bool needsStubLink = false;
 698
 699     // Checks out okay!
 700     if (slot.cachedPropertyType() == PropertySlot::Getter) {
 701         needsStubLink = true;
 702         compileGetDirectOffset(protoObject, regT1, cachedOffset);
 703         JITStubCall stubCall(this, cti_op_get_by_id_getter_stub);
 704         stubCall.addArgument(regT1);
 705         stubCall.addArgument(regT0);
 706         stubCall.addArgument(TrustedImmPtr(stubInfo->callReturnLocation.executableAddress()));
 707         stubCall.call();
 708     } else if (slot.cachedPropertyType() == PropertySlot::Custom) {
 709         needsStubLink = true;
 710         JITStubCall stubCall(this, cti_op_get_by_id_custom_stub);
 711         stubCall.addArgument(TrustedImmPtr(protoObject));
 712         stubCall.addArgument(TrustedImmPtr(FunctionPtr(slot.customGetter()).executableAddress()));
 713         stubCall.addArgument(TrustedImmPtr(const_cast<Identifier*>(&ident)));
 714         stubCall.addArgument(TrustedImmPtr(stubInfo->callReturnLocation.executableAddress()));
 715         stubCall.call();
 716     } else
 717         compileGetDirectOffset(protoObject, regT0, cachedOffset);
 718     Jump success = jump();
 719     LinkBuffer patchBuffer(*m_globalData, this, m_codeBlock);
 720
 721     // Use the patch information to link the failure cases back to the original slow case routine.
 722     CodeLocationLabel slowCaseBegin = stubInfo->callReturnLocation.labelAtOffset(-stubInfo->patch.baseline.u.get.coldPathBegin);
 723     patchBuffer.link(failureCases1, slowCaseBegin);
 724     patchBuffer.link(failureCases2, slowCaseBegin);
 725
 726     // On success return back to the hot patch code, at a point it will perform the store to dest for us.
 727     patchBuffer.link(success, stubInfo->hotPathBegin.labelAtOffset(stubInfo->patch.baseline.u.get.putResult));
 728
 729     if (needsStubLink) {
 730         for (Vector<CallRecord>::iterator iter = m_calls.begin(); iter != m_calls.end(); ++iter) {
 731             if (iter->to)
 732                 patchBuffer.link(iter->from, FunctionPtr(iter->to));
 733         }
 734     }
 735     // Track the stub we have created so that it will be deleted later.
 736     stubInfo->stubRoutine = createJITStubRoutine(
 737         FINALIZE_CODE(
 738             patchBuffer,
 739             ("Baseline JIT get_by_id proto stub for CodeBlock %p, return point %p",
 740              m_codeBlock, stubInfo->hotPathBegin.labelAtOffset(
 741                  stubInfo->patch.baseline.u.get.putResult).executableAddress())),
 742         *m_globalData,
 743         m_codeBlock->ownerExecutable(),
 744         needsStubLink);
 745
 746     // Finally patch the jump to slow case back in the hot path to jump here instead.
 747     CodeLocationJump jumpLocation = stubInfo->hotPathBegin.jumpAtOffset(stubInfo->patch.baseline.u.get.structureCheck);
 748     RepatchBuffer repatchBuffer(m_codeBlock);
 749     repatchBuffer.relink(jumpLocation, CodeLocationLabel(stubInfo->stubRoutine->code().code()));
 750
 751     // We don't want to patch more than once - in future go to cti_op_put_by_id_generic.
 752     repatchBuffer.relinkCallerToFunction(returnAddress, FunctionPtr(cti_op_get_by_id_proto_list));
 753 }
 754
 755 void JIT::privateCompileGetByIdSelfList(StructureStubInfo* stubInfo, PolymorphicAccessStructureList* polymorphicStructures, int currentIndex, Structure* structure, const Identifier& ident, const PropertySlot& slot, PropertyOffset cachedOffset)
 756 {
 757     Jump failureCase = checkStructure(regT0, structure);
 758     bool needsStubLink = false;
 759     bool isDirect = false;
 760     if (slot.cachedPropertyType() == PropertySlot::Getter) {
 761         needsStubLink = true;
 762         compileGetDirectOffset(regT0, regT1, cachedOffset);
 763         JITStubCall stubCall(this, cti_op_get_by_id_getter_stub);
 764         stubCall.addArgument(regT1);
 765         stubCall.addArgument(regT0);
 766         stubCall.addArgument(TrustedImmPtr(stubInfo->callReturnLocation.executableAddress()));
 767         stubCall.call();
 768     } else if (slot.cachedPropertyType() == PropertySlot::Custom) {
 769         needsStubLink = true;
 770         JITStubCall stubCall(this, cti_op_get_by_id_custom_stub);
 771         stubCall.addArgument(regT0);
 772         stubCall.addArgument(TrustedImmPtr(FunctionPtr(slot.customGetter()).executableAddress()));
 773         stubCall.addArgument(TrustedImmPtr(const_cast<Identifier*>(&ident)));
 774         stubCall.addArgument(TrustedImmPtr(stubInfo->callReturnLocation.executableAddress()));
 775         stubCall.call();
 776     } else {
 777         isDirect = true;
 778         compileGetDirectOffset(regT0, regT0, cachedOffset);
 779     }
 780     Jump success = jump();
 781
 782     LinkBuffer patchBuffer(*m_globalData, this, m_codeBlock);
 783
 784     if (needsStubLink) {
 785         for (Vector<CallRecord>::iterator iter = m_calls.begin(); iter != m_calls.end(); ++iter) {
 786             if (iter->to)
 787                 patchBuffer.link(iter->from, FunctionPtr(iter->to));
 788         }
 789     }
 790
 791     // Use the patch information to link the failure cases back to the original slow case routine.
 792     CodeLocationLabel lastProtoBegin = CodeLocationLabel(JITStubRoutine::asCodePtr(polymorphicStructures->list[currentIndex - 1].stubRoutine));
 793     if (!lastProtoBegin)
 794         lastProtoBegin = stubInfo->callReturnLocation.labelAtOffset(-stubInfo->patch.baseline.u.get.coldPathBegin);
 795
 796     patchBuffer.link(failureCase, lastProtoBegin);
 797
 798     // On success return back to the hot patch code, at a point it will perform the store to dest for us.
 799     patchBuffer.link(success, stubInfo->hotPathBegin.labelAtOffset(stubInfo->patch.baseline.u.get.putResult));
 800
 801     RefPtr<JITStubRoutine> stubCode = createJITStubRoutine(
 802         FINALIZE_CODE(
 803             patchBuffer,
 804             ("Baseline JIT get_by_id list stub for CodeBlock %p, return point %p",
 805              m_codeBlock, stubInfo->hotPathBegin.labelAtOffset(
 806                  stubInfo->patch.baseline.u.get.putResult).executableAddress())),
 807         *m_globalData,
 808         m_codeBlock->ownerExecutable(),
 809         needsStubLink);
 810
 811     polymorphicStructures->list[currentIndex].set(*m_globalData, m_codeBlock->ownerExecutable(), stubCode, structure, isDirect);
 812
 813     // Finally patch the jump to slow case back in the hot path to jump here instead.
 814     CodeLocationJump jumpLocation = stubInfo->hotPathBegin.jumpAtOffset(stubInfo->patch.baseline.u.get.structureCheck);
 815     RepatchBuffer repatchBuffer(m_codeBlock);
 816     repatchBuffer.relink(jumpLocation, CodeLocationLabel(stubCode->code().code()));
 817 }
 818
 819 void JIT::privateCompileGetByIdProtoList(StructureStubInfo* stubInfo, PolymorphicAccessStructureList* prototypeStructures, int currentIndex, Structure* structure, Structure* prototypeStructure, const Identifier& ident, const PropertySlot& slot, PropertyOffset cachedOffset, CallFrame* callFrame)
 820 {
 821     // The prototype object definitely exists (if this stub exists the CodeBlock is referencing a Structure that is
 822     // referencing the prototype object - let's speculatively load it's table nice and early!)
 823     JSObject* protoObject = asObject(structure->prototypeForLookup(callFrame));
 824
 825     // Check eax is an object of the right Structure.
 826     Jump failureCases1 = checkStructure(regT0, structure);
 827
 828     // Check the prototype object's Structure had not changed.
 829     move(TrustedImmPtr(protoObject), regT3);
 830     Jump failureCases2 = branchPtr(NotEqual, Address(regT3, JSCell::structureOffset()), TrustedImmPtr(prototypeStructure));
 831
 832     // Checks out okay!
 833     bool needsStubLink = false;
 834     bool isDirect = false;
 835     if (slot.cachedPropertyType() == PropertySlot::Getter) {
 836         needsStubLink = true;
 837         compileGetDirectOffset(protoObject, regT1, cachedOffset);
 838         JITStubCall stubCall(this, cti_op_get_by_id_getter_stub);
 839         stubCall.addArgument(regT1);
 840         stubCall.addArgument(regT0);
 841         stubCall.addArgument(TrustedImmPtr(stubInfo->callReturnLocation.executableAddress()));
 842         stubCall.call();
 843     } else if (slot.cachedPropertyType() == PropertySlot::Custom) {
 844         needsStubLink = true;
 845         JITStubCall stubCall(this, cti_op_get_by_id_custom_stub);
 846         stubCall.addArgument(TrustedImmPtr(protoObject));
 847         stubCall.addArgument(TrustedImmPtr(FunctionPtr(slot.customGetter()).executableAddress()));
 848         stubCall.addArgument(TrustedImmPtr(const_cast<Identifier*>(&ident)));
 849         stubCall.addArgument(TrustedImmPtr(stubInfo->callReturnLocation.executableAddress()));
 850         stubCall.call();
 851     } else {
 852         isDirect = true;
 853         compileGetDirectOffset(protoObject, regT0, cachedOffset);
 854     }
 855
 856     Jump success = jump();
 857
 858     LinkBuffer patchBuffer(*m_globalData, this, m_codeBlock);
 859
 860     if (needsStubLink) {
 861         for (Vector<CallRecord>::iterator iter = m_calls.begin(); iter != m_calls.end(); ++iter) {
 862             if (iter->to)
 863                 patchBuffer.link(iter->from, FunctionPtr(iter->to));
 864         }
 865     }
 866
 867     // Use the patch information to link the failure cases back to the original slow case routine.
 868     CodeLocationLabel lastProtoBegin = CodeLocationLabel(JITStubRoutine::asCodePtr(prototypeStructures->list[currentIndex - 1].stubRoutine));
 869     patchBuffer.link(failureCases1, lastProtoBegin);
 870     patchBuffer.link(failureCases2, lastProtoBegin);
 871
 872     // On success return back to the hot patch code, at a point it will perform the store to dest for us.
 873     patchBuffer.link(success, stubInfo->hotPathBegin.labelAtOffset(stubInfo->patch.baseline.u.get.putResult));
 874
 875     RefPtr<JITStubRoutine> stubCode = createJITStubRoutine(
 876         FINALIZE_CODE(
 877             patchBuffer,
 878             ("Baseline JIT get_by_id proto list stub for CodeBlock %p, return point %p",
 879              m_codeBlock, stubInfo->hotPathBegin.labelAtOffset(
 880                  stubInfo->patch.baseline.u.get.putResult).executableAddress())),
 881         *m_globalData,
 882         m_codeBlock->ownerExecutable(),
 883         needsStubLink);
 884     prototypeStructures->list[currentIndex].set(*m_globalData, m_codeBlock->ownerExecutable(), stubCode, structure, prototypeStructure, isDirect);
 885
 886     // Finally patch the jump to slow case back in the hot path to jump here instead.
 887     CodeLocationJump jumpLocation = stubInfo->hotPathBegin.jumpAtOffset(stubInfo->patch.baseline.u.get.structureCheck);
 888     RepatchBuffer repatchBuffer(m_codeBlock);
 889     repatchBuffer.relink(jumpLocation, CodeLocationLabel(stubCode->code().code()));
 890 }
 891
 892 void JIT::privateCompileGetByIdChainList(StructureStubInfo* stubInfo, PolymorphicAccessStructureList* prototypeStructures, int currentIndex, Structure* structure, StructureChain* chain, size_t count, const Identifier& ident, const PropertySlot& slot, PropertyOffset cachedOffset, CallFrame* callFrame)
 893 {
 894     ASSERT(count);
 895     JumpList bucketsOfFail;
 896
 897     // Check eax is an object of the right Structure.
 898     Jump baseObjectCheck = checkStructure(regT0, structure);
 899     bucketsOfFail.append(baseObjectCheck);
 900
 901     Structure* currStructure = structure;
 902     WriteBarrier<Structure>* it = chain->head();
 903     JSObject* protoObject = 0;
 904     for (unsigned i = 0; i < count; ++i, ++it) {
 905         protoObject = asObject(currStructure->prototypeForLookup(callFrame));
 906         currStructure = it->get();
 907         testPrototype(protoObject, bucketsOfFail);
 908     }
 909     ASSERT(protoObject);
 910
 911     bool needsStubLink = false;
 912     bool isDirect = false;
 913     if (slot.cachedPropertyType() == PropertySlot::Getter) {
 914         needsStubLink = true;
 915         compileGetDirectOffset(protoObject, regT1, cachedOffset);
 916         JITStubCall stubCall(this, cti_op_get_by_id_getter_stub);
 917         stubCall.addArgument(regT1);
 918         stubCall.addArgument(regT0);
 919         stubCall.addArgument(TrustedImmPtr(stubInfo->callReturnLocation.executableAddress()));
 920         stubCall.call();
 921     } else if (slot.cachedPropertyType() == PropertySlot::Custom) {
 922         needsStubLink = true;
 923         JITStubCall stubCall(this, cti_op_get_by_id_custom_stub);
 924         stubCall.addArgument(TrustedImmPtr(protoObject));
 925         stubCall.addArgument(TrustedImmPtr(FunctionPtr(slot.customGetter()).executableAddress()));
 926         stubCall.addArgument(TrustedImmPtr(const_cast<Identifier*>(&ident)));
 927         stubCall.addArgument(TrustedImmPtr(stubInfo->callReturnLocation.executableAddress()));
 928         stubCall.call();
 929     } else {
 930         isDirect = true;
 931         compileGetDirectOffset(protoObject, regT0, cachedOffset);
 932     }
 933     Jump success = jump();
 934
 935     LinkBuffer patchBuffer(*m_globalData, this, m_codeBlock);
 936
 937     if (needsStubLink) {
 938         for (Vector<CallRecord>::iterator iter = m_calls.begin(); iter != m_calls.end(); ++iter) {
 939             if (iter->to)
 940                 patchBuffer.link(iter->from, FunctionPtr(iter->to));
 941         }
 942     }
 943
 944     // Use the patch information to link the failure cases back to the original slow case routine.
 945     CodeLocationLabel lastProtoBegin = CodeLocationLabel(JITStubRoutine::asCodePtr(prototypeStructures->list[currentIndex - 1].stubRoutine));
 946
 947     patchBuffer.link(bucketsOfFail, lastProtoBegin);
 948
 949     // On success return back to the hot patch code, at a point it will perform the store to dest for us.
 950     patchBuffer.link(success, stubInfo->hotPathBegin.labelAtOffset(stubInfo->patch.baseline.u.get.putResult));
 951
 952     RefPtr<JITStubRoutine> stubRoutine = createJITStubRoutine(
 953         FINALIZE_CODE(
 954             patchBuffer,
 955             ("Baseline JIT get_by_id chain list stub for CodeBlock %p, return point %p",
 956              m_codeBlock, stubInfo->hotPathBegin.labelAtOffset(
 957                  stubInfo->patch.baseline.u.get.putResult).executableAddress())),
 958         *m_globalData,
 959         m_codeBlock->ownerExecutable(),
 960         needsStubLink);
 961
 962     // Track the stub we have created so that it will be deleted later.
 963     prototypeStructures->list[currentIndex].set(callFrame->globalData(), m_codeBlock->ownerExecutable(), stubRoutine, structure, chain, isDirect);
 964
 965     // Finally patch the jump to slow case back in the hot path to jump here instead.
 966     CodeLocationJump jumpLocation = stubInfo->hotPathBegin.jumpAtOffset(stubInfo->patch.baseline.u.get.structureCheck);
 967     RepatchBuffer repatchBuffer(m_codeBlock);
 968     repatchBuffer.relink(jumpLocation, CodeLocationLabel(stubRoutine->code().code()));
 969 }
 970
 971 void JIT::privateCompileGetByIdChain(StructureStubInfo* stubInfo, Structure* structure, StructureChain* chain, size_t count, const Identifier& ident, const PropertySlot& slot, PropertyOffset cachedOffset, ReturnAddressPtr returnAddress, CallFrame* callFrame)
 972 {
 973     ASSERT(count);
 974
 975     JumpList bucketsOfFail;
 976
 977     // Check eax is an object of the right Structure.
 978     bucketsOfFail.append(checkStructure(regT0, structure));
 979
 980     Structure* currStructure = structure;
 981     WriteBarrier<Structure>* it = chain->head();
 982     JSObject* protoObject = 0;
 983     for (unsigned i = 0; i < count; ++i, ++it) {
 984         protoObject = asObject(currStructure->prototypeForLookup(callFrame));
 985         currStructure = it->get();
 986         testPrototype(protoObject, bucketsOfFail);
 987     }
 988     ASSERT(protoObject);
 989
 990     bool needsStubLink = false;
 991     if (slot.cachedPropertyType() == PropertySlot::Getter) {
 992         needsStubLink = true;
 993         compileGetDirectOffset(protoObject, regT1, cachedOffset);
 994         JITStubCall stubCall(this, cti_op_get_by_id_getter_stub);
 995         stubCall.addArgument(regT1);
 996         stubCall.addArgument(regT0);
 997         stubCall.addArgument(TrustedImmPtr(stubInfo->callReturnLocation.executableAddress()));
 998         stubCall.call();
 999     } else if (slot.cachedPropertyType() == PropertySlot::Custom) {
1000         needsStubLink = true;
1001         JITStubCall stubCall(this, cti_op_get_by_id_custom_stub);
1002         stubCall.addArgument(TrustedImmPtr(protoObject));
1003         stubCall.addArgument(TrustedImmPtr(FunctionPtr(slot.customGetter()).executableAddress()));
1004         stubCall.addArgument(TrustedImmPtr(const_cast<Identifier*>(&ident)));
1005         stubCall.addArgument(TrustedImmPtr(stubInfo->callReturnLocation.executableAddress()));
1006         stubCall.call();
1007     } else
1008         compileGetDirectOffset(protoObject, regT0, cachedOffset);
1009     Jump success = jump();
1010
1011     LinkBuffer patchBuffer(*m_globalData, this, m_codeBlock);
1012
1013     if (needsStubLink) {
1014         for (Vector<CallRecord>::iterator iter = m_calls.begin(); iter != m_calls.end(); ++iter) {
1015             if (iter->to)
1016                 patchBuffer.link(iter->from, FunctionPtr(iter->to));
1017         }
1018     }
1019
1020     // Use the patch information to link the failure cases back to the original slow case routine.
1021     patchBuffer.link(bucketsOfFail, stubInfo->callReturnLocation.labelAtOffset(-stubInfo->patch.baseline.u.get.coldPathBegin));
1022
1023     // On success return back to the hot patch code, at a point it will perform the store to dest for us.
1024     patchBuffer.link(success, stubInfo->hotPathBegin.labelAtOffset(stubInfo->patch.baseline.u.get.putResult));
1025
1026     // Track the stub we have created so that it will be deleted later.
1027     RefPtr<JITStubRoutine> stubRoutine = createJITStubRoutine(
1028         FINALIZE_CODE(
1029             patchBuffer,
1030             ("Baseline JIT get_by_id chain stub for CodeBlock %p, return point %p",
1031              m_codeBlock, stubInfo->hotPathBegin.labelAtOffset(
1032                  stubInfo->patch.baseline.u.get.putResult).executableAddress())),
1033         *m_globalData,
1034         m_codeBlock->ownerExecutable(),
1035         needsStubLink);
1036     stubInfo->stubRoutine = stubRoutine;
1037
1038     // Finally patch the jump to slow case back in the hot path to jump here instead.
1039     CodeLocationJump jumpLocation = stubInfo->hotPathBegin.jumpAtOffset(stubInfo->patch.baseline.u.get.structureCheck);
1040     RepatchBuffer repatchBuffer(m_codeBlock);
1041     repatchBuffer.relink(jumpLocation, CodeLocationLabel(stubRoutine->code().code()));
1042
1043     // We don't want to patch more than once - in future go to cti_op_put_by_id_generic.
1044     repatchBuffer.relinkCallerToFunction(returnAddress, FunctionPtr(cti_op_get_by_id_proto_list));
1045 }
1046
1047 void JIT::emit_op_get_scoped_var(Instruction* currentInstruction)
1048 {
1049     int skip = currentInstruction[3].u.operand;
1050
1051     emitGetFromCallFrameHeaderPtr(RegisterFile::ScopeChain, regT0);
1052     bool checkTopLevel = m_codeBlock->codeType() == FunctionCode && m_codeBlock->needsFullScopeChain();
1053     ASSERT(skip || !checkTopLevel);
1054     if (checkTopLevel && skip--) {
1055         Jump activationNotCreated;
1056         if (checkTopLevel)
1057             activationNotCreated = branchTestPtr(Zero, addressFor(m_codeBlock->activationRegister()));
1058         loadPtr(Address(regT0, OBJECT_OFFSETOF(ScopeChainNode, next)), regT0);
1059         activationNotCreated.link(this);
1060     }
1061     while (skip--)
1062         loadPtr(Address(regT0, OBJECT_OFFSETOF(ScopeChainNode, next)), regT0);
1063
1064     loadPtr(Address(regT0, OBJECT_OFFSETOF(ScopeChainNode, object)), regT0);
1065     loadPtr(Address(regT0, JSVariableObject::offsetOfRegisters()), regT0);
1066     loadPtr(Address(regT0, currentInstruction[2].u.operand * sizeof(Register)), regT0);
1067     emitValueProfilingSite();
1068     emitPutVirtualRegister(currentInstruction[1].u.operand);
1069 }
1070
1071 void JIT::emit_op_put_scoped_var(Instruction* currentInstruction)
1072 {
1073     int skip = currentInstruction[2].u.operand;
1074
1075     emitGetVirtualRegister(currentInstruction[3].u.operand, regT0);
1076
1077     emitGetFromCallFrameHeaderPtr(RegisterFile::ScopeChain, regT1);
1078     bool checkTopLevel = m_codeBlock->codeType() == FunctionCode && m_codeBlock->needsFullScopeChain();
1079     ASSERT(skip || !checkTopLevel);
1080     if (checkTopLevel && skip--) {
1081         Jump activationNotCreated;
1082         if (checkTopLevel)
1083             activationNotCreated = branchTestPtr(Zero, addressFor(m_codeBlock->activationRegister()));
1084         loadPtr(Address(regT1, OBJECT_OFFSETOF(ScopeChainNode, next)), regT1);
1085         activationNotCreated.link(this);
1086     }
1087     while (skip--)
1088         loadPtr(Address(regT1, OBJECT_OFFSETOF(ScopeChainNode, next)), regT1);
1089     loadPtr(Address(regT1, OBJECT_OFFSETOF(ScopeChainNode, object)), regT1);
1090
1091     emitWriteBarrier(regT1, regT0, regT2, regT3, ShouldFilterImmediates, WriteBarrierForVariableAccess);
1092
1093     loadPtr(Address(regT1, JSVariableObject::offsetOfRegisters()), regT1);
1094     storePtr(regT0, Address(regT1, currentInstruction[1].u.operand * sizeof(Register)));
1095 }
1096
1097 void JIT::emit_op_get_global_var(Instruction* currentInstruction)
1098 {
1099     loadPtr(currentInstruction[2].u.registerPointer, regT0);
1100     emitValueProfilingSite();
1101     emitPutVirtualRegister(currentInstruction[1].u.operand);
1102 }
1103
1104 void JIT::emit_op_put_global_var(Instruction* currentInstruction)
1105 {
1106     JSGlobalObject* globalObject = m_codeBlock->globalObject();
1107
1108     emitGetVirtualRegister(currentInstruction[2].u.operand, regT0);
1109
1110     storePtr(regT0, currentInstruction[1].u.registerPointer);
1111     if (Heap::isWriteBarrierEnabled())
1112         emitWriteBarrier(globalObject, regT0, regT2, ShouldFilterImmediates, WriteBarrierForVariableAccess);
1113 }
1114
1115 void JIT::emit_op_put_global_var_check(Instruction* currentInstruction)
1116 {
1117     emitGetVirtualRegister(currentInstruction[2].u.operand, regT0);
1118
1119     addSlowCase(branchTest8(NonZero, AbsoluteAddress(currentInstruction[3].u.predicatePointer)));
1120
1121     JSGlobalObject* globalObject = m_codeBlock->globalObject();
1122
1123     storePtr(regT0, currentInstruction[1].u.registerPointer);
1124     if (Heap::isWriteBarrierEnabled())
1125         emitWriteBarrier(globalObject, regT0, regT2, ShouldFilterImmediates, WriteBarrierForVariableAccess);
1126 }
1127
1128 void JIT::emitSlow_op_put_global_var_check(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
1129 {
1130     linkSlowCase(iter);
1131
1132     JITStubCall stubCall(this, cti_op_put_global_var_check);
1133     stubCall.addArgument(regT0);
1134     stubCall.addArgument(TrustedImm32(currentInstruction[4].u.operand));
1135     stubCall.call();
1136 }
1137
1138 void JIT::resetPatchGetById(RepatchBuffer& repatchBuffer, StructureStubInfo* stubInfo)
1139 {
1140     repatchBuffer.relink(stubInfo->callReturnLocation, cti_op_get_by_id);
1141     repatchBuffer.repatch(stubInfo->hotPathBegin.dataLabelPtrAtOffset(stubInfo->patch.baseline.u.get.structureToCompare), reinterpret_cast<void*>(-1));
1142     repatchBuffer.repatch(stubInfo->hotPathBegin.dataLabelCompactAtOffset(stubInfo->patch.baseline.u.get.displacementLabel), 0);
1143     repatchBuffer.relink(stubInfo->hotPathBegin.jumpAtOffset(stubInfo->patch.baseline.u.get.structureCheck), stubInfo->callReturnLocation.labelAtOffset(-stubInfo->patch.baseline.u.get.coldPathBegin));
1144 }
1145
1146 void JIT::resetPatchPutById(RepatchBuffer& repatchBuffer, StructureStubInfo* stubInfo)
1147 {
1148     if (isDirectPutById(stubInfo))
1149         repatchBuffer.relink(stubInfo->callReturnLocation, cti_op_put_by_id_direct);
1150     else
1151         repatchBuffer.relink(stubInfo->callReturnLocation, cti_op_put_by_id);
1152     repatchBuffer.repatch(stubInfo->hotPathBegin.dataLabelPtrAtOffset(stubInfo->patch.baseline.u.put.structureToCompare), reinterpret_cast<void*>(-1));
1153     repatchBuffer.repatch(stubInfo->hotPathBegin.dataLabelCompactAtOffset(stubInfo->patch.baseline.u.put.displacementLabel), 0);
1154 }
1155
1156 #endif // USE(JSVALUE64)
1157
1158 void JIT::emitWriteBarrier(RegisterID owner, RegisterID value, RegisterID scratch, RegisterID scratch2, WriteBarrierMode mode, WriteBarrierUseKind useKind)
1159 {
1160     UNUSED_PARAM(owner);
1161     UNUSED_PARAM(scratch);
1162     UNUSED_PARAM(scratch2);
1163     UNUSED_PARAM(useKind);
1164     UNUSED_PARAM(value);
1165     UNUSED_PARAM(mode);
1166     ASSERT(owner != scratch);
1167     ASSERT(owner != scratch2);
1168
1169 #if ENABLE(WRITE_BARRIER_PROFILING)
1170     emitCount(WriteBarrierCounters::jitCounterFor(useKind));
1171 #endif
1172
1173 #if ENABLE(GGC)
1174     Jump filterCells;
1175     if (mode == ShouldFilterImmediates)
1176         filterCells = emitJumpIfNotJSCell(value);
1177     move(owner, scratch);
1178     andPtr(TrustedImm32(static_cast<int32_t>(MarkedBlock::blockMask)), scratch);
1179     move(owner, scratch2);
1180     // consume additional 8 bits as we're using an approximate filter
1181     rshift32(TrustedImm32(MarkedBlock::atomShift + 8), scratch2);
1182     andPtr(TrustedImm32(MarkedBlock::atomMask >> 8), scratch2);
1183     Jump filter = branchTest8(Zero, BaseIndex(scratch, scratch2, TimesOne, MarkedBlock::offsetOfMarks()));
1184     move(owner, scratch2);
1185     rshift32(TrustedImm32(MarkedBlock::cardShift), scratch2);
1186     andPtr(TrustedImm32(MarkedBlock::cardMask), scratch2);
1187     store8(TrustedImm32(1), BaseIndex(scratch, scratch2, TimesOne, MarkedBlock::offsetOfCards()));
1188     filter.link(this);
1189     if (mode == ShouldFilterImmediates)
1190         filterCells.link(this);
1191 #endif
1192 }
1193
1194 void JIT::emitWriteBarrier(JSCell* owner, RegisterID value, RegisterID scratch, WriteBarrierMode mode, WriteBarrierUseKind useKind)
1195 {
1196     UNUSED_PARAM(owner);
1197     UNUSED_PARAM(scratch);
1198     UNUSED_PARAM(useKind);
1199     UNUSED_PARAM(value);
1200     UNUSED_PARAM(mode);
1201
1202 #if ENABLE(WRITE_BARRIER_PROFILING)
1203     emitCount(WriteBarrierCounters::jitCounterFor(useKind));
1204 #endif
1205
1206 #if ENABLE(GGC)
1207     Jump filterCells;
1208     if (mode == ShouldFilterImmediates)
1209         filterCells = emitJumpIfNotJSCell(value);
1210     uint8_t* cardAddress = Heap::addressOfCardFor(owner);
1211     move(TrustedImmPtr(cardAddress), scratch);
1212     store8(TrustedImm32(1), Address(scratch));
1213     if (mode == ShouldFilterImmediates)
1214         filterCells.link(this);
1215 #endif
1216 }
1217
1218 void JIT::testPrototype(JSValue prototype, JumpList& failureCases)
1219 {
1220     if (prototype.isNull())
1221         return;
1222
1223     ASSERT(prototype.isCell());
1224     move(TrustedImmPtr(prototype.asCell()), regT3);
1225     failureCases.append(branchPtr(NotEqual, Address(regT3, JSCell::structureOffset()), TrustedImmPtr(prototype.asCell()->structure())));
1226 }
1227
1228 void JIT::patchMethodCallProto(JSGlobalData& globalData, CodeBlock* codeBlock, MethodCallLinkInfo& methodCallLinkInfo, StructureStubInfo& stubInfo, JSObject* callee, Structure* structure, JSObject* proto, ReturnAddressPtr returnAddress)
1229 {
1230     RepatchBuffer repatchBuffer(codeBlock);
1231
1232     CodeLocationDataLabelPtr structureLocation = methodCallLinkInfo.cachedStructure.location();
1233     methodCallLinkInfo.cachedStructure.set(globalData, structureLocation, codeBlock->ownerExecutable(), structure);
1234
1235     Structure* prototypeStructure = proto->structure();
1236     methodCallLinkInfo.cachedPrototypeStructure.set(globalData, structureLocation.dataLabelPtrAtOffset(stubInfo.patch.baseline.methodCheckProtoStructureToCompare), codeBlock->ownerExecutable(), prototypeStructure);
1237     methodCallLinkInfo.cachedPrototype.set(globalData, structureLocation.dataLabelPtrAtOffset(stubInfo.patch.baseline.methodCheckProtoObj), codeBlock->ownerExecutable(), proto);
1238     methodCallLinkInfo.cachedFunction.set(globalData, structureLocation.dataLabelPtrAtOffset(stubInfo.patch.baseline.methodCheckPutFunction), codeBlock->ownerExecutable(), callee);
1239     repatchBuffer.relinkCallerToFunction(returnAddress, FunctionPtr(cti_op_get_by_id_method_check_update));
1240 }
1241
1242 bool JIT::isDirectPutById(StructureStubInfo* stubInfo)
1243 {
1244     switch (stubInfo->accessType) {
1245     case access_put_by_id_transition_normal:
1246         return false;
1247     case access_put_by_id_transition_direct:
1248         return true;
1249     case access_put_by_id_replace:
1250     case access_put_by_id_generic: {
1251         void* oldCall = MacroAssembler::readCallTarget(stubInfo->callReturnLocation).executableAddress();
1252         if (oldCall == bitwise_cast<void*>(cti_op_put_by_id_direct)
1253             || oldCall == bitwise_cast<void*>(cti_op_put_by_id_direct_generic)
1254             || oldCall == bitwise_cast<void*>(cti_op_put_by_id_direct_fail))
1255             return true;
1256         ASSERT(oldCall == bitwise_cast<void*>(cti_op_put_by_id)
1257                || oldCall == bitwise_cast<void*>(cti_op_put_by_id_generic)
1258                || oldCall == bitwise_cast<void*>(cti_op_put_by_id_fail));
1259         return false;
1260     }
1261     default:
1262         ASSERT_NOT_REACHED();
1263         return false;
1264     }
1265 }
1266
1267 } // namespace JSC
1268
1269 #endif // ENABLE(JIT)