]> git.saurik.com Git - apple/javascriptcore.git/blobdiff - jit/JITPropertyAccess.cpp
JavaScriptCore-903.5.tar.gz
[apple/javascriptcore.git] / jit / JITPropertyAccess.cpp
index 6740becbea7bb814d486272e3c17a73b0e386555..ce3d3c1f385504a83359a1aeecee9f665a430256 100644 (file)
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2008 Apple Inc. All rights reserved.
+ * Copyright (C) 2008, 2009 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  */
 
 #include "config.h"
-#include "JIT.h"
 
 #if ENABLE(JIT)
+#include "JIT.h"
 
 #include "CodeBlock.h"
+#include "GetterSetter.h"
 #include "JITInlineMethods.h"
+#include "JITStubCall.h"
 #include "JSArray.h"
 #include "JSFunction.h"
+#include "JSPropertyNameIterator.h"
 #include "Interpreter.h"
+#include "LinkBuffer.h"
+#include "RepatchBuffer.h"
 #include "ResultType.h"
 #include "SamplingTool.h"
 
 using namespace std;
 
 namespace JSC {
+#if USE(JSVALUE64)
 
-#if !ENABLE(JIT_OPTIMIZE_PROPERTY_ACCESS)
+JIT::CodePtr JIT::stringGetByValStubGenerator(JSGlobalData* globalData, ExecutablePool* pool)
+{
+    JSInterfaceJIT jit;
+    JumpList failures;
+    failures.append(jit.branchPtr(NotEqual, Address(regT0), TrustedImmPtr(globalData->jsStringVPtr)));
+    failures.append(jit.branchTest32(NonZero, Address(regT0, OBJECT_OFFSETOF(JSString, m_fiberCount))));
+
+    // Load string length to regT2, and start the process of loading the data pointer into regT0
+    jit.load32(Address(regT0, ThunkHelpers::jsStringLengthOffset()), regT2);
+    jit.loadPtr(Address(regT0, ThunkHelpers::jsStringValueOffset()), regT0);
+    jit.loadPtr(Address(regT0, ThunkHelpers::stringImplDataOffset()), regT0);
+    
+    // Do an unsigned compare to simultaneously filter negative indices as well as indices that are too large
+    failures.append(jit.branch32(AboveOrEqual, regT1, regT2));
+    
+    // Load the character
+    jit.load16(BaseIndex(regT0, regT1, TimesTwo, 0), regT0);
+    
+    failures.append(jit.branch32(AboveOrEqual, regT0, TrustedImm32(0x100)));
+    jit.move(TrustedImmPtr(globalData->smallStrings.singleCharacterStrings()), regT1);
+    jit.loadPtr(BaseIndex(regT1, regT0, ScalePtr, 0), regT0);
+    jit.ret();
+    
+    failures.link(&jit);
+    jit.move(TrustedImm32(0), regT0);
+    jit.ret();
+    
+    LinkBuffer patchBuffer(*globalData, &jit, pool);
+    return patchBuffer.finalizeCode().m_code;
+}
 
-void JIT::compileGetByIdHotPath(int resultVReg, int baseVReg, Identifier* ident, unsigned)
+void JIT::emit_op_get_by_val(Instruction* currentInstruction)
 {
-    // As for put_by_id, get_by_id requires the offset of the Structure and the offset of the access to be patched.
-    // Additionally, for get_by_id we need patch the offset of the branch to the slow case (we patch this to jump
-    // to array-length / prototype access tranpolines, and finally we also the the property-map access offset as a label
-    // to jump back to if one of these trampolies finds a match.
+    unsigned dst = currentInstruction[1].u.operand;
+    unsigned base = currentInstruction[2].u.operand;
+    unsigned property = currentInstruction[3].u.operand;
 
-    emitGetVirtualRegister(baseVReg, X86::eax);
+    emitGetVirtualRegisters(base, regT0, property, regT1);
+    emitJumpSlowCaseIfNotImmediateInteger(regT1);
 
-    emitPutJITStubArg(X86::eax, 1);
-    emitPutJITStubArgConstant(ident, 2);
-    emitCTICall(Interpreter::cti_op_get_by_id_generic);
-    emitPutVirtualRegister(resultVReg);
+    // This is technically incorrect - we're zero-extending an int32.  On the hot path this doesn't matter.
+    // We check the value as if it was a uint32 against the m_vectorLength - which will always fail if
+    // number was signed since m_vectorLength is always less than intmax (since the total allocation
+    // size is always less than 4Gb).  As such zero extending wil have been correct (and extending the value
+    // to 64-bits is necessary since it's used in the address calculation.  We zero extend rather than sign
+    // extending since it makes it easier to re-tag the value in the slow case.
+    zeroExtend32ToPtr(regT1, regT1);
+
+    emitJumpSlowCaseIfNotJSCell(regT0, base);
+    addSlowCase(branchPtr(NotEqual, Address(regT0), TrustedImmPtr(m_globalData->jsArrayVPtr)));
+
+    loadPtr(Address(regT0, JSArray::storageOffset()), regT2);
+    addSlowCase(branch32(AboveOrEqual, regT1, Address(regT0, JSArray::vectorLengthOffset())));
+
+    loadPtr(BaseIndex(regT2, regT1, ScalePtr, OBJECT_OFFSETOF(ArrayStorage, m_vector[0])), regT0);
+    addSlowCase(branchTestPtr(Zero, regT0));
+
+    emitPutVirtualRegister(dst);
+}
+
+void JIT::emitSlow_op_get_by_val(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
+{
+    unsigned dst = currentInstruction[1].u.operand;
+    unsigned base = currentInstruction[2].u.operand;
+    unsigned property = currentInstruction[3].u.operand;
+    
+    linkSlowCase(iter); // property int32 check
+    linkSlowCaseIfNotJSCell(iter, base); // base cell check
+    Jump nonCell = jump();
+    linkSlowCase(iter); // base array check
+    Jump notString = branchPtr(NotEqual, Address(regT0), TrustedImmPtr(m_globalData->jsStringVPtr));
+    emitNakedCall(m_globalData->getCTIStub(stringGetByValStubGenerator));
+    Jump failed = branchTestPtr(Zero, regT0);
+    emitPutVirtualRegister(dst, regT0);
+    emitJumpSlowToHot(jump(), OPCODE_LENGTH(op_get_by_val));
+    failed.link(this);
+    notString.link(this);
+    nonCell.link(this);
+    
+    linkSlowCase(iter); // vector length check
+    linkSlowCase(iter); // empty value
+    
+    JITStubCall stubCall(this, cti_op_get_by_val);
+    stubCall.addArgument(base, regT2);
+    stubCall.addArgument(property, regT2);
+    stubCall.call(dst);
+}
+
+void JIT::compileGetDirectOffset(RegisterID base, RegisterID result, RegisterID offset, RegisterID scratch)
+{
+    loadPtr(Address(base, OBJECT_OFFSETOF(JSObject, m_propertyStorage)), scratch);
+    loadPtr(BaseIndex(scratch, offset, ScalePtr, 0), result);
+}
+
+void JIT::emit_op_get_by_pname(Instruction* currentInstruction)
+{
+    unsigned dst = currentInstruction[1].u.operand;
+    unsigned base = currentInstruction[2].u.operand;
+    unsigned property = currentInstruction[3].u.operand;
+    unsigned expected = currentInstruction[4].u.operand;
+    unsigned iter = currentInstruction[5].u.operand;
+    unsigned i = currentInstruction[6].u.operand;
+
+    emitGetVirtualRegister(property, regT0);
+    addSlowCase(branchPtr(NotEqual, regT0, addressFor(expected)));
+    emitGetVirtualRegisters(base, regT0, iter, regT1);
+    emitJumpSlowCaseIfNotJSCell(regT0, base);
+
+    // Test base's structure
+    loadPtr(Address(regT0, JSCell::structureOffset()), regT2);
+    addSlowCase(branchPtr(NotEqual, regT2, Address(regT1, OBJECT_OFFSETOF(JSPropertyNameIterator, m_cachedStructure))));
+    load32(addressFor(i), regT3);
+    sub32(TrustedImm32(1), regT3);
+    addSlowCase(branch32(AboveOrEqual, regT3, Address(regT1, OBJECT_OFFSETOF(JSPropertyNameIterator, m_numCacheableSlots))));
+    compileGetDirectOffset(regT0, regT0, regT3, regT1);
+
+    emitPutVirtualRegister(dst, regT0);
+}
+
+void JIT::emitSlow_op_get_by_pname(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
+{
+    unsigned dst = currentInstruction[1].u.operand;
+    unsigned base = currentInstruction[2].u.operand;
+    unsigned property = currentInstruction[3].u.operand;
+
+    linkSlowCase(iter);
+    linkSlowCaseIfNotJSCell(iter, base);
+    linkSlowCase(iter);
+    linkSlowCase(iter);
+
+    JITStubCall stubCall(this, cti_op_get_by_val);
+    stubCall.addArgument(base, regT2);
+    stubCall.addArgument(property, regT2);
+    stubCall.call(dst);
+}
+
+void JIT::emit_op_put_by_val(Instruction* currentInstruction)
+{
+    unsigned base = currentInstruction[1].u.operand;
+    unsigned property = currentInstruction[2].u.operand;
+    unsigned value = currentInstruction[3].u.operand;
+
+    emitGetVirtualRegisters(base, regT0, property, regT1);
+    emitJumpSlowCaseIfNotImmediateInteger(regT1);
+    // See comment in op_get_by_val.
+    zeroExtend32ToPtr(regT1, regT1);
+    emitJumpSlowCaseIfNotJSCell(regT0, base);
+    addSlowCase(branchPtr(NotEqual, Address(regT0), TrustedImmPtr(m_globalData->jsArrayVPtr)));
+    addSlowCase(branch32(AboveOrEqual, regT1, Address(regT0, JSArray::vectorLengthOffset())));
+
+    loadPtr(Address(regT0, JSArray::storageOffset()), regT2);
+    Jump empty = branchTestPtr(Zero, BaseIndex(regT2, regT1, ScalePtr, OBJECT_OFFSETOF(ArrayStorage, m_vector[0])));
+
+    Label storeResult(this);
+    emitGetVirtualRegister(value, regT0);
+    storePtr(regT0, BaseIndex(regT2, regT1, ScalePtr, OBJECT_OFFSETOF(ArrayStorage, m_vector[0])));
+    Jump end = jump();
+    
+    empty.link(this);
+    add32(TrustedImm32(1), Address(regT2, OBJECT_OFFSETOF(ArrayStorage, m_numValuesInVector)));
+    branch32(Below, regT1, Address(regT2, OBJECT_OFFSETOF(ArrayStorage, m_length))).linkTo(storeResult, this);
+
+    move(regT1, regT0);
+    add32(TrustedImm32(1), regT0);
+    store32(regT0, Address(regT2, OBJECT_OFFSETOF(ArrayStorage, m_length)));
+    jump().linkTo(storeResult, this);
+
+    end.link(this);
+}
+
+void JIT::emit_op_put_by_index(Instruction* currentInstruction)
+{
+    JITStubCall stubCall(this, cti_op_put_by_index);
+    stubCall.addArgument(currentInstruction[1].u.operand, regT2);
+    stubCall.addArgument(TrustedImm32(currentInstruction[2].u.operand));
+    stubCall.addArgument(currentInstruction[3].u.operand, regT2);
+    stubCall.call();
+}
+
+void JIT::emit_op_put_getter(Instruction* currentInstruction)
+{
+    JITStubCall stubCall(this, cti_op_put_getter);
+    stubCall.addArgument(currentInstruction[1].u.operand, regT2);
+    stubCall.addArgument(TrustedImmPtr(&m_codeBlock->identifier(currentInstruction[2].u.operand)));
+    stubCall.addArgument(currentInstruction[3].u.operand, regT2);
+    stubCall.call();
+}
+
+void JIT::emit_op_put_setter(Instruction* currentInstruction)
+{
+    JITStubCall stubCall(this, cti_op_put_setter);
+    stubCall.addArgument(currentInstruction[1].u.operand, regT2);
+    stubCall.addArgument(TrustedImmPtr(&m_codeBlock->identifier(currentInstruction[2].u.operand)));
+    stubCall.addArgument(currentInstruction[3].u.operand, regT2);
+    stubCall.call();
+}
+
+void JIT::emit_op_del_by_id(Instruction* currentInstruction)
+{
+    JITStubCall stubCall(this, cti_op_del_by_id);
+    stubCall.addArgument(currentInstruction[2].u.operand, regT2);
+    stubCall.addArgument(TrustedImmPtr(&m_codeBlock->identifier(currentInstruction[3].u.operand)));
+    stubCall.call(currentInstruction[1].u.operand);
 }
 
 
-void JIT::compileGetByIdSlowCase(int, int, Identifier*, Vector<SlowCaseEntry>::iterator&, unsigned)
+#if !ENABLE(JIT_OPTIMIZE_PROPERTY_ACCESS)
+
+/* ------------------------------ BEGIN: !ENABLE(JIT_OPTIMIZE_PROPERTY_ACCESS) ------------------------------ */
+
+// Treat these as nops - the call will be handed as a regular get_by_id/op_call pair.
+void JIT::emit_op_method_check(Instruction*) {}
+void JIT::emitSlow_op_method_check(Instruction*, Vector<SlowCaseEntry>::iterator&) { ASSERT_NOT_REACHED(); }
+#if ENABLE(JIT_OPTIMIZE_METHOD_CALLS)
+#error "JIT_OPTIMIZE_METHOD_CALLS requires JIT_OPTIMIZE_PROPERTY_ACCESS"
+#endif
+
+void JIT::emit_op_get_by_id(Instruction* currentInstruction)
+{
+    unsigned resultVReg = currentInstruction[1].u.operand;
+    unsigned baseVReg = currentInstruction[2].u.operand;
+    Identifier* ident = &(m_codeBlock->identifier(currentInstruction[3].u.operand));
+
+    emitGetVirtualRegister(baseVReg, regT0);
+    JITStubCall stubCall(this, cti_op_get_by_id_generic);
+    stubCall.addArgument(regT0);
+    stubCall.addArgument(TrustedImmPtr(ident));
+    stubCall.call(resultVReg);
+
+    m_propertyAccessInstructionIndex++;
+}
+
+void JIT::emitSlow_op_get_by_id(Instruction*, Vector<SlowCaseEntry>::iterator&)
 {
     ASSERT_NOT_REACHED();
 }
 
-void JIT::compilePutByIdHotPath(int baseVReg, Identifier* ident, int valueVReg, unsigned)
+void JIT::emit_op_put_by_id(Instruction* currentInstruction)
 {
-    // In order to be able to patch both the Structure, and the object offset, we store one pointer,
-    // to just after the arguments have been loaded into registers 'hotPathBegin', and we generate code
-    // such that the Structure & offset are always at the same distance from this.
+    unsigned baseVReg = currentInstruction[1].u.operand;
+    Identifier* ident = &(m_codeBlock->identifier(currentInstruction[2].u.operand));
+    unsigned valueVReg = currentInstruction[3].u.operand;
+    unsigned direct = currentInstruction[8].u.operand;
+
+    emitGetVirtualRegisters(baseVReg, regT0, valueVReg, regT1);
 
-    emitGetVirtualRegisters(baseVReg, X86::eax, valueVReg, X86::edx);
+    JITStubCall stubCall(this, direct ? cti_op_put_by_id_direct_generic, cti_op_put_by_id_generic);
+    stubCall.addArgument(regT0);
+    stubCall.addArgument(TrustedImmPtr(ident));
+    stubCall.addArgument(regT1);
+    stubCall.call();
 
-    emitPutJITStubArgConstant(ident, 2);
-    emitPutJITStubArg(X86::eax, 1);
-    emitPutJITStubArg(X86::edx, 3);
-    emitCTICall(Interpreter::cti_op_put_by_id_generic);
+    m_propertyAccessInstructionIndex++;
 }
 
-void JIT::compilePutByIdSlowCase(int, Identifier*, int, Vector<SlowCaseEntry>::iterator&, unsigned)
+void JIT::emitSlow_op_put_by_id(Instruction*, Vector<SlowCaseEntry>::iterator&)
 {
     ASSERT_NOT_REACHED();
 }
 
-#else
+#else // !ENABLE(JIT_OPTIMIZE_PROPERTY_ACCESS)
+
+/* ------------------------------ BEGIN: ENABLE(JIT_OPTIMIZE_PROPERTY_ACCESS) ------------------------------ */
+
+#if ENABLE(JIT_OPTIMIZE_METHOD_CALLS)
 
-void JIT::compileGetByIdHotPath(int resultVReg, int baseVReg, Identifier*, unsigned propertyAccessInstructionIndex)
+void JIT::emit_op_method_check(Instruction* currentInstruction)
+{
+    // Assert that the following instruction is a get_by_id.
+    ASSERT(m_interpreter->getOpcodeID((currentInstruction + OPCODE_LENGTH(op_method_check))->u.opcode) == op_get_by_id);
+
+    currentInstruction += OPCODE_LENGTH(op_method_check);
+    unsigned resultVReg = currentInstruction[1].u.operand;
+    unsigned baseVReg = currentInstruction[2].u.operand;
+    Identifier* ident = &(m_codeBlock->identifier(currentInstruction[3].u.operand));
+
+    emitGetVirtualRegister(baseVReg, regT0);
+
+    // Do the method check - check the object & its prototype's structure inline (this is the common case).
+    m_methodCallCompilationInfo.append(MethodCallCompilationInfo(m_propertyAccessInstructionIndex));
+    MethodCallCompilationInfo& info = m_methodCallCompilationInfo.last();
+
+    Jump notCell = emitJumpIfNotJSCell(regT0);
+
+    BEGIN_UNINTERRUPTED_SEQUENCE(sequenceMethodCheck);
+
+    Jump structureCheck = branchPtrWithPatch(NotEqual, Address(regT0, JSCell::structureOffset()), info.structureToCompare, TrustedImmPtr(reinterpret_cast<void*>(patchGetByIdDefaultStructure)));
+    DataLabelPtr protoStructureToCompare, protoObj = moveWithPatch(TrustedImmPtr(0), regT1);
+    Jump protoStructureCheck = branchPtrWithPatch(NotEqual, Address(regT1, JSCell::structureOffset()), protoStructureToCompare, TrustedImmPtr(reinterpret_cast<void*>(patchGetByIdDefaultStructure)));
+
+    // This will be relinked to load the function without doing a load.
+    DataLabelPtr putFunction = moveWithPatch(TrustedImmPtr(0), regT0);
+
+    END_UNINTERRUPTED_SEQUENCE(sequenceMethodCheck);
+
+    Jump match = jump();
+
+    ASSERT_JIT_OFFSET_UNUSED(protoObj, differenceBetween(info.structureToCompare, protoObj), patchOffsetMethodCheckProtoObj);
+    ASSERT_JIT_OFFSET(differenceBetween(info.structureToCompare, protoStructureToCompare), patchOffsetMethodCheckProtoStruct);
+    ASSERT_JIT_OFFSET_UNUSED(putFunction, differenceBetween(info.structureToCompare, putFunction), patchOffsetMethodCheckPutFunction);
+
+    // Link the failure cases here.
+    notCell.link(this);
+    structureCheck.link(this);
+    protoStructureCheck.link(this);
+
+    // Do a regular(ish) get_by_id (the slow case will be link to
+    // cti_op_get_by_id_method_check instead of cti_op_get_by_id.
+    compileGetByIdHotPath(resultVReg, baseVReg, ident, m_propertyAccessInstructionIndex++);
+
+    match.link(this);
+    emitPutVirtualRegister(resultVReg);
+
+    // We've already generated the following get_by_id, so make sure it's skipped over.
+    m_bytecodeOffset += OPCODE_LENGTH(op_get_by_id);
+}
+
+void JIT::emitSlow_op_method_check(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
+{
+    currentInstruction += OPCODE_LENGTH(op_method_check);
+    unsigned resultVReg = currentInstruction[1].u.operand;
+    unsigned baseVReg = currentInstruction[2].u.operand;
+    Identifier* ident = &(m_codeBlock->identifier(currentInstruction[3].u.operand));
+
+    compileGetByIdSlowCase(resultVReg, baseVReg, ident, iter, true);
+
+    // We've already generated the following get_by_id, so make sure it's skipped over.
+    m_bytecodeOffset += OPCODE_LENGTH(op_get_by_id);
+}
+
+#else //!ENABLE(JIT_OPTIMIZE_METHOD_CALLS)
+
+// Treat these as nops - the call will be handed as a regular get_by_id/op_call pair.
+void JIT::emit_op_method_check(Instruction*) {}
+void JIT::emitSlow_op_method_check(Instruction*, Vector<SlowCaseEntry>::iterator&) { ASSERT_NOT_REACHED(); }
+
+#endif
+
+void JIT::emit_op_get_by_id(Instruction* currentInstruction)
+{
+    unsigned resultVReg = currentInstruction[1].u.operand;
+    unsigned baseVReg = currentInstruction[2].u.operand;
+    Identifier* ident = &(m_codeBlock->identifier(currentInstruction[3].u.operand));
+
+    emitGetVirtualRegister(baseVReg, regT0);
+    compileGetByIdHotPath(resultVReg, baseVReg, ident, m_propertyAccessInstructionIndex++);
+    emitPutVirtualRegister(resultVReg);
+}
+
+void JIT::compileGetByIdHotPath(int, int baseVReg, Identifier*, unsigned propertyAccessInstructionIndex)
 {
     // As for put_by_id, get_by_id requires the offset of the Structure and the offset of the access to be patched.
     // Additionally, for get_by_id we need patch the offset of the branch to the slow case (we patch this to jump
     // to array-length / prototype access tranpolines, and finally we also the the property-map access offset as a label
     // to jump back to if one of these trampolies finds a match.
 
-    emitGetVirtualRegister(baseVReg, X86::eax);
+    emitJumpSlowCaseIfNotJSCell(regT0, baseVReg);
 
-    emitJumpSlowCaseIfNotJSCell(X86::eax, baseVReg);
+    BEGIN_UNINTERRUPTED_SEQUENCE(sequenceGetByIdHotPath);
 
     Label hotPathBegin(this);
     m_propertyAccessCompilationInfo[propertyAccessInstructionIndex].hotPathBegin = hotPathBegin;
 
     DataLabelPtr structureToCompare;
-    Jump structureCheck = jnePtrWithPatch(Address(X86::eax, FIELD_OFFSET(JSCell, m_structure)), structureToCompare, ImmPtr(reinterpret_cast<void*>(patchGetByIdDefaultStructure)));
+    Jump structureCheck = branchPtrWithPatch(NotEqual, Address(regT0, JSCell::structureOffset()), structureToCompare, TrustedImmPtr(reinterpret_cast<void*>(patchGetByIdDefaultStructure)));
     addSlowCase(structureCheck);
-    ASSERT(differenceBetween(hotPathBegin, structureToCompare) == patchOffsetGetByIdStructure);
-    ASSERT(differenceBetween(hotPathBegin, structureCheck) == patchOffsetGetByIdBranchToSlowCase);
+    ASSERT_JIT_OFFSET(differenceBetween(hotPathBegin, structureToCompare), patchOffsetGetByIdStructure);
+    ASSERT_JIT_OFFSET(differenceBetween(hotPathBegin, structureCheck), patchOffsetGetByIdBranchToSlowCase)
 
-    loadPtr(Address(X86::eax, FIELD_OFFSET(JSObject, m_propertyStorage)), X86::eax);
-    DataLabel32 displacementLabel = loadPtrWithAddressOffsetPatch(Address(X86::eax, patchGetByIdDefaultOffset), X86::eax);
-    ASSERT(differenceBetween(hotPathBegin, displacementLabel) == patchOffsetGetByIdPropertyMapOffset);
+    loadPtr(Address(regT0, OBJECT_OFFSETOF(JSObject, m_propertyStorage)), regT0);
+    DataLabelCompact displacementLabel = loadPtrWithCompactAddressOffsetPatch(Address(regT0, patchGetByIdDefaultOffset), regT0);
+    ASSERT_JIT_OFFSET_UNUSED(displacementLabel, differenceBetween(hotPathBegin, displacementLabel), patchOffsetGetByIdPropertyMapOffset);
 
     Label putResult(this);
-    ASSERT(differenceBetween(hotPathBegin, putResult) == patchOffsetGetByIdPutResult);
-    emitPutVirtualRegister(resultVReg);
+
+    END_UNINTERRUPTED_SEQUENCE(sequenceGetByIdHotPath);
+
+    ASSERT_JIT_OFFSET(differenceBetween(hotPathBegin, putResult), patchOffsetGetByIdPutResult);
 }
 
+void JIT::emitSlow_op_get_by_id(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
+{
+    unsigned resultVReg = currentInstruction[1].u.operand;
+    unsigned baseVReg = currentInstruction[2].u.operand;
+    Identifier* ident = &(m_codeBlock->identifier(currentInstruction[3].u.operand));
 
-void JIT::compileGetByIdSlowCase(int resultVReg, int baseVReg, Identifier* ident, Vector<SlowCaseEntry>::iterator& iter, unsigned propertyAccessInstructionIndex)
+    compileGetByIdSlowCase(resultVReg, baseVReg, ident, iter, false);
+}
+
+void JIT::compileGetByIdSlowCase(int resultVReg, int baseVReg, Identifier* ident, Vector<SlowCaseEntry>::iterator& iter, bool isMethodCheck)
 {
     // As for the hot path of get_by_id, above, we ensure that we can use an architecture specific offset
     // so that we only need track one pointer into the slow case code - we track a pointer to the location
@@ -129,576 +450,586 @@ void JIT::compileGetByIdSlowCase(int resultVReg, int baseVReg, Identifier* ident
     linkSlowCaseIfNotJSCell(iter, baseVReg);
     linkSlowCase(iter);
 
+    BEGIN_UNINTERRUPTED_SEQUENCE(sequenceGetByIdSlowCase);
+
 #ifndef NDEBUG
     Label coldPathBegin(this);
 #endif
-    emitPutJITStubArg(X86::eax, 1);
-    emitPutJITStubArgConstant(ident, 2);
-    Jump call = emitCTICall(Interpreter::cti_op_get_by_id);
-    emitPutVirtualRegister(resultVReg);
+    JITStubCall stubCall(this, isMethodCheck ? cti_op_get_by_id_method_check : cti_op_get_by_id);
+    stubCall.addArgument(regT0);
+    stubCall.addArgument(TrustedImmPtr(ident));
+    Call call = stubCall.call(resultVReg);
+
+    END_UNINTERRUPTED_SEQUENCE(sequenceGetByIdSlowCase);
 
-    ASSERT(differenceBetween(coldPathBegin, call) == patchOffsetGetByIdSlowCaseCall);
+    ASSERT_JIT_OFFSET(differenceBetween(coldPathBegin, call), patchOffsetGetByIdSlowCaseCall);
 
     // Track the location of the call; this will be used to recover patch information.
-    m_propertyAccessCompilationInfo[propertyAccessInstructionIndex].callReturnLocation = call;
+    m_propertyAccessCompilationInfo[m_propertyAccessInstructionIndex].callReturnLocation = call;
+    m_propertyAccessInstructionIndex++;
 }
 
-void JIT::compilePutByIdHotPath(int baseVReg, Identifier*, int valueVReg, unsigned propertyAccessInstructionIndex)
+void JIT::emit_op_put_by_id(Instruction* currentInstruction)
 {
+    unsigned baseVReg = currentInstruction[1].u.operand;
+    unsigned valueVReg = currentInstruction[3].u.operand;
+
+    unsigned propertyAccessInstructionIndex = m_propertyAccessInstructionIndex++;
+
     // In order to be able to patch both the Structure, and the object offset, we store one pointer,
     // to just after the arguments have been loaded into registers 'hotPathBegin', and we generate code
     // such that the Structure & offset are always at the same distance from this.
 
-    emitGetVirtualRegisters(baseVReg, X86::eax, valueVReg, X86::edx);
+    emitGetVirtualRegisters(baseVReg, regT0, valueVReg, regT1);
 
     // Jump to a slow case if either the base object is an immediate, or if the Structure does not match.
-    emitJumpSlowCaseIfNotJSCell(X86::eax, baseVReg);
+    emitJumpSlowCaseIfNotJSCell(regT0, baseVReg);
+
+    BEGIN_UNINTERRUPTED_SEQUENCE(sequencePutById);
 
     Label hotPathBegin(this);
     m_propertyAccessCompilationInfo[propertyAccessInstructionIndex].hotPathBegin = hotPathBegin;
 
     // It is important that the following instruction plants a 32bit immediate, in order that it can be patched over.
     DataLabelPtr structureToCompare;
-    addSlowCase(jnePtrWithPatch(Address(X86::eax, FIELD_OFFSET(JSCell, m_structure)), structureToCompare, ImmPtr(reinterpret_cast<void*>(patchGetByIdDefaultStructure))));
-    ASSERT(differenceBetween(hotPathBegin, structureToCompare) == patchOffsetPutByIdStructure);
+    addSlowCase(branchPtrWithPatch(NotEqual, Address(regT0, JSCell::structureOffset()), structureToCompare, TrustedImmPtr(reinterpret_cast<void*>(patchGetByIdDefaultStructure))));
+    ASSERT_JIT_OFFSET(differenceBetween(hotPathBegin, structureToCompare), patchOffsetPutByIdStructure);
+
+    loadPtr(Address(regT0, OBJECT_OFFSETOF(JSObject, m_propertyStorage)), regT0);
+    DataLabel32 displacementLabel = storePtrWithAddressOffsetPatch(regT1, Address(regT0, patchPutByIdDefaultOffset));
 
-    // Plant a load from a bogus ofset in the object's property map; we will patch this later, if it is to be used.
-    loadPtr(Address(X86::eax, FIELD_OFFSET(JSObject, m_propertyStorage)), X86::eax);
-    DataLabel32 displacementLabel = storePtrWithAddressOffsetPatch(X86::edx, Address(X86::eax, patchGetByIdDefaultOffset));
-    ASSERT(differenceBetween(hotPathBegin, displacementLabel) == patchOffsetPutByIdPropertyMapOffset);
+    END_UNINTERRUPTED_SEQUENCE(sequencePutById);
+
+    ASSERT_JIT_OFFSET_UNUSED(displacementLabel, differenceBetween(hotPathBegin, displacementLabel), patchOffsetPutByIdPropertyMapOffset);
 }
 
-void JIT::compilePutByIdSlowCase(int baseVReg, Identifier* ident, int, Vector<SlowCaseEntry>::iterator& iter, unsigned propertyAccessInstructionIndex)
+void JIT::emitSlow_op_put_by_id(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
 {
+    unsigned baseVReg = currentInstruction[1].u.operand;
+    Identifier* ident = &(m_codeBlock->identifier(currentInstruction[2].u.operand));
+    unsigned direct = currentInstruction[8].u.operand;
+
+    unsigned propertyAccessInstructionIndex = m_propertyAccessInstructionIndex++;
+
     linkSlowCaseIfNotJSCell(iter, baseVReg);
     linkSlowCase(iter);
 
-    emitPutJITStubArgConstant(ident, 2);
-    emitPutJITStubArg(X86::eax, 1);
-    emitPutJITStubArg(X86::edx, 3);
-    Jump call = emitCTICall(Interpreter::cti_op_put_by_id);
+    JITStubCall stubCall(this, direct ? cti_op_put_by_id_direct : cti_op_put_by_id);
+    stubCall.addArgument(regT0);
+    stubCall.addArgument(TrustedImmPtr(ident));
+    stubCall.addArgument(regT1);
+    Call call = stubCall.call();
 
     // Track the location of the call; this will be used to recover patch information.
     m_propertyAccessCompilationInfo[propertyAccessInstructionIndex].callReturnLocation = call;
 }
 
-static JSObject* resizePropertyStorage(JSObject* baseObject, int32_t oldSize, int32_t newSize)
+// Compile a store into an object's property storage.  May overwrite the
+// value in objectReg.
+void JIT::compilePutDirectOffset(RegisterID base, RegisterID value, Structure* structure, size_t cachedOffset)
+{
+    int offset = cachedOffset * sizeof(JSValue);
+    if (structure->isUsingInlineStorage())
+        offset += JSObject::offsetOfInlineStorage();
+    else
+        loadPtr(Address(base, OBJECT_OFFSETOF(JSObject, m_propertyStorage)), base);
+    storePtr(value, Address(base, offset));
+}
+
+// Compile a load from an object's property storage.  May overwrite base.
+void JIT::compileGetDirectOffset(RegisterID base, RegisterID result, Structure* structure, size_t cachedOffset)
 {
-    baseObject->allocatePropertyStorage(oldSize, newSize);
-    return baseObject;
+    int offset = cachedOffset * sizeof(JSValue);
+    if (structure->isUsingInlineStorage()) {
+        offset += JSObject::offsetOfInlineStorage();
+        loadPtr(Address(base, offset), result);
+    } else {
+        loadPtr(Address(base, OBJECT_OFFSETOF(JSObject, m_propertyStorage)), result);
+        loadPtr(Address(result, offset), result);
+    }
 }
 
-static inline bool transitionWillNeedStorageRealloc(Structure* oldStructure, Structure* newStructure)
+void JIT::compileGetDirectOffset(JSObject* base, RegisterID result, size_t cachedOffset)
 {
-    return oldStructure->propertyStorageCapacity() != newStructure->propertyStorageCapacity();
+    loadPtr(static_cast<void*>(&base->m_propertyStorage[cachedOffset]), result);
 }
 
-void JIT::privateCompilePutByIdTransition(StructureStubInfo* stubInfo, Structure* oldStructure, Structure* newStructure, size_t cachedOffset, StructureChain* chain, void* returnAddress)
+void JIT::privateCompilePutByIdTransition(StructureStubInfo* stubInfo, Structure* oldStructure, Structure* newStructure, size_t cachedOffset, StructureChain* chain, ReturnAddressPtr returnAddress, bool direct)
 {
     JumpList failureCases;
     // Check eax is an object of the right Structure.
-    failureCases.append(emitJumpIfNotJSCell(X86::eax));
-    failureCases.append(jnePtr(Address(X86::eax, FIELD_OFFSET(JSCell, m_structure)), ImmPtr(oldStructure)));
-    JumpList successCases;
+    failureCases.append(emitJumpIfNotJSCell(regT0));
+    failureCases.append(branchPtr(NotEqual, Address(regT0, JSCell::structureOffset()), TrustedImmPtr(oldStructure)));
+    testPrototype(oldStructure->storedPrototype(), failureCases);
 
-    //  ecx = baseObject
-    loadPtr(Address(X86::eax, FIELD_OFFSET(JSCell, m_structure)), X86::ecx);
-    // proto(ecx) = baseObject->structure()->prototype()
-    failureCases.append(jne32(Address(X86::ecx, FIELD_OFFSET(Structure, m_typeInfo) + FIELD_OFFSET(TypeInfo, m_type)), Imm32(ObjectType)));
-
-    loadPtr(Address(X86::ecx, FIELD_OFFSET(Structure, m_prototype)), X86::ecx);
-    
     // ecx = baseObject->m_structure
-    for (RefPtr<Structure>* it = chain->head(); *it; ++it) {
-        // null check the prototype
-        successCases.append(jePtr(X86::ecx, ImmPtr(JSValuePtr::encode(jsNull()))));
-
-        // Check the structure id
-        failureCases.append(jnePtr(Address(X86::ecx, FIELD_OFFSET(JSCell, m_structure)), ImmPtr(it->get())));
-        
-        loadPtr(Address(X86::ecx, FIELD_OFFSET(JSCell, m_structure)), X86::ecx);
-        failureCases.append(jne32(Address(X86::ecx, FIELD_OFFSET(Structure, m_typeInfo) + FIELD_OFFSET(TypeInfo, m_type)), Imm32(ObjectType)));
-        loadPtr(Address(X86::ecx, FIELD_OFFSET(Structure, m_prototype)), X86::ecx);
+    if (!direct) {
+        for (WriteBarrier<Structure>* it = chain->head(); *it; ++it)
+            testPrototype((*it)->storedPrototype(), failureCases);
     }
 
-    successCases.link(this);
-
-    Jump callTarget;
+    Call callTarget;
 
     // emit a call only if storage realloc is needed
-    if (transitionWillNeedStorageRealloc(oldStructure, newStructure)) {
-        pop(X86::ebx);
-#if PLATFORM(X86_64)
-        move(Imm32(newStructure->propertyStorageCapacity()), X86::edx);
-        move(Imm32(oldStructure->propertyStorageCapacity()), X86::esi);
-        move(X86::eax, X86::edi);
-        callTarget = call();
-#else
-        push(Imm32(newStructure->propertyStorageCapacity()));
-        push(Imm32(oldStructure->propertyStorageCapacity()));
-        push(X86::eax);
-        callTarget = call();
-        addPtr(Imm32(3 * sizeof(void*)), X86::esp);
-#endif
-        emitGetJITStubArg(3, X86::edx);
-        push(X86::ebx);
+    bool willNeedStorageRealloc = oldStructure->propertyStorageCapacity() != newStructure->propertyStorageCapacity();
+    if (willNeedStorageRealloc) {
+        // This trampoline was called to like a JIT stub; before we can can call again we need to
+        // remove the return address from the stack, to prevent the stack from becoming misaligned.
+        preserveReturnAddressAfterCall(regT3);
+        JITStubCall stubCall(this, cti_op_put_by_id_transition_realloc);
+        stubCall.skipArgument(); // base
+        stubCall.skipArgument(); // ident
+        stubCall.skipArgument(); // value
+        stubCall.addArgument(TrustedImm32(oldStructure->propertyStorageCapacity()));
+        stubCall.addArgument(TrustedImm32(newStructure->propertyStorageCapacity()));
+        stubCall.call(regT0);
+        emitGetJITStubArg(2, regT1);
+
+        restoreReturnAddressBeforeReturn(regT3);
     }
 
-    // Assumes m_refCount can be decremented easily, refcount decrement is safe as 
-    // codeblock should ensure oldStructure->m_refCount > 0
-    sub32(Imm32(1), AbsoluteAddress(oldStructure->addressOfCount()));
-    add32(Imm32(1), AbsoluteAddress(newStructure->addressOfCount()));
-    storePtr(ImmPtr(newStructure), Address(X86::eax, FIELD_OFFSET(JSCell, m_structure)));
+    storePtrWithWriteBarrier(TrustedImmPtr(newStructure), regT0, Address(regT0, JSCell::structureOffset()));
 
     // write the value
-    loadPtr(Address(X86::eax, FIELD_OFFSET(JSObject, m_propertyStorage)), X86::eax);
-    storePtr(X86::edx, Address(X86::eax, cachedOffset * sizeof(JSValuePtr)));
+    compilePutDirectOffset(regT0, regT1, newStructure, cachedOffset);
 
     ret();
     
-    Jump failureJump;
-    bool plantedFailureJump = false;
-    if (!failureCases.empty()) {
-        failureCases.link(this);
-        restoreArgumentReferenceForTrampoline();
-        failureJump = jump();
-        plantedFailureJump = true;
-    }
+    ASSERT(!failureCases.empty());
+    failureCases.link(this);
+    restoreArgumentReferenceForTrampoline();
+    Call failureCall = tailRecursiveCall();
 
-    void* code = m_assembler.executableCopy(m_codeBlock->executablePool());
-    PatchBuffer patchBuffer(code);
+    LinkBuffer patchBuffer(*m_globalData, this, m_codeBlock->executablePool());
 
-    if (plantedFailureJump)
-        patchBuffer.link(failureJump, reinterpret_cast<void*>(Interpreter::cti_op_put_by_id_fail));
+    patchBuffer.link(failureCall, FunctionPtr(direct ? cti_op_put_by_id_direct_fail : cti_op_put_by_id_fail));
 
-    if (transitionWillNeedStorageRealloc(oldStructure, newStructure))
-        patchBuffer.link(callTarget, reinterpret_cast<void*>(resizePropertyStorage));
-    
-    stubInfo->stubRoutine = code;
+    if (willNeedStorageRealloc) {
+        ASSERT(m_calls.size() == 1);
+        patchBuffer.link(m_calls[0].from, FunctionPtr(cti_op_put_by_id_transition_realloc));
+    }
     
-    Jump::patch(returnAddress, code);
+    CodeLocationLabel entryLabel = patchBuffer.finalizeCodeAddendum();
+    stubInfo->stubRoutine = entryLabel;
+    RepatchBuffer repatchBuffer(m_codeBlock);
+    repatchBuffer.relinkCallerToTrampoline(returnAddress, entryLabel);
 }
 
-void JIT::patchGetByIdSelf(StructureStubInfo* stubInfo, Structure* structure, size_t cachedOffset, void* returnAddress)
+void JIT::patchGetByIdSelf(CodeBlock* codeBlock, StructureStubInfo* stubInfo, Structure* structure, size_t cachedOffset, ReturnAddressPtr returnAddress)
 {
+    RepatchBuffer repatchBuffer(codeBlock);
+
     // We don't want to patch more than once - in future go to cti_op_get_by_id_generic.
-    // Should probably go to Interpreter::cti_op_get_by_id_fail, but that doesn't do anything interesting right now.
-    Jump::patch(returnAddress, reinterpret_cast<void*>(Interpreter::cti_op_get_by_id_self_fail));
+    // Should probably go to cti_op_get_by_id_fail, but that doesn't do anything interesting right now.
+    repatchBuffer.relinkCallerToFunction(returnAddress, FunctionPtr(cti_op_get_by_id_self_fail));
+
+    int offset = sizeof(JSValue) * cachedOffset;
 
     // Patch the offset into the propoerty map to load from, then patch the Structure to look for.
-    void* structureAddress = reinterpret_cast<void*>(reinterpret_cast<intptr_t>(stubInfo->hotPathBegin) + patchOffsetGetByIdStructure);
-    void* displacementAddress = reinterpret_cast<void*>(reinterpret_cast<intptr_t>(stubInfo->hotPathBegin) + patchOffsetGetByIdPropertyMapOffset);
-    DataLabelPtr::patch(structureAddress, structure);
-    DataLabel32::patch(displacementAddress, cachedOffset * sizeof(JSValuePtr));
+    repatchBuffer.repatch(stubInfo->hotPathBegin.dataLabelPtrAtOffset(patchOffsetGetByIdStructure), structure);
+    repatchBuffer.repatch(stubInfo->hotPathBegin.dataLabelCompactAtOffset(patchOffsetGetByIdPropertyMapOffset), offset);
 }
 
-void JIT::patchPutByIdReplace(StructureStubInfo* stubInfo, Structure* structure, size_t cachedOffset, void* returnAddress)
+void JIT::patchPutByIdReplace(CodeBlock* codeBlock, StructureStubInfo* stubInfo, Structure* structure, size_t cachedOffset, ReturnAddressPtr returnAddress, bool direct)
 {
+    RepatchBuffer repatchBuffer(codeBlock);
+
     // We don't want to patch more than once - in future go to cti_op_put_by_id_generic.
-    // Should probably go to Interpreter::cti_op_put_by_id_fail, but that doesn't do anything interesting right now.
-    Jump::patch(returnAddress, reinterpret_cast<void*>(Interpreter::cti_op_put_by_id_generic));
+    // Should probably go to cti_op_put_by_id_fail, but that doesn't do anything interesting right now.
+    repatchBuffer.relinkCallerToFunction(returnAddress, FunctionPtr(direct ? cti_op_put_by_id_direct_generic : cti_op_put_by_id_generic));
+
+    int offset = sizeof(JSValue) * cachedOffset;
 
     // Patch the offset into the propoerty map to load from, then patch the Structure to look for.
-    void* structureAddress = reinterpret_cast<char*>(stubInfo->hotPathBegin) + patchOffsetPutByIdStructure;
-    void* displacementAddress = reinterpret_cast<char*>(stubInfo->hotPathBegin) + patchOffsetPutByIdPropertyMapOffset;
-    DataLabelPtr::patch(structureAddress, structure);
-    DataLabel32::patch(displacementAddress, cachedOffset * sizeof(JSValuePtr));
+    repatchBuffer.repatch(stubInfo->hotPathBegin.dataLabelPtrAtOffset(patchOffsetPutByIdStructure), structure);
+    repatchBuffer.repatch(stubInfo->hotPathBegin.dataLabel32AtOffset(patchOffsetPutByIdPropertyMapOffset), offset);
 }
 
-void JIT::privateCompilePatchGetArrayLength(void* returnAddress)
+void JIT::privateCompilePatchGetArrayLength(ReturnAddressPtr returnAddress)
 {
     StructureStubInfo* stubInfo = &m_codeBlock->getStubInfo(returnAddress);
 
-    // We don't want to patch more than once - in future go to cti_op_put_by_id_generic.
-    Jump::patch(returnAddress, reinterpret_cast<void*>(Interpreter::cti_op_get_by_id_array_fail));
-
     // Check eax is an array
-    Jump failureCases1 = jnePtr(Address(X86::eax), ImmPtr(m_interpreter->m_jsArrayVptr));
+    Jump failureCases1 = branchPtr(NotEqual, Address(regT0), TrustedImmPtr(m_globalData->jsArrayVPtr));
 
     // Checks out okay! - get the length from the storage
-    loadPtr(Address(X86::eax, FIELD_OFFSET(JSArray, m_storage)), X86::ecx);
-    load32(Address(X86::ecx, FIELD_OFFSET(ArrayStorage, m_length)), X86::ecx);
-
-    Jump failureCases2 = ja32(X86::ecx, Imm32(JSImmediate::maxImmediateInt));
+    loadPtr(Address(regT0, JSArray::storageOffset()), regT3);
+    load32(Address(regT3, OBJECT_OFFSETOF(ArrayStorage, m_length)), regT2);
+    Jump failureCases2 = branch32(LessThan, regT2, TrustedImm32(0));
 
-    emitFastArithIntToImmNoCheck(X86::ecx, X86::eax);
+    emitFastArithIntToImmNoCheck(regT2, regT0);
     Jump success = jump();
 
-    void* code = m_assembler.executableCopy(m_codeBlock->executablePool());
-    PatchBuffer patchBuffer(code);
+    LinkBuffer patchBuffer(*m_globalData, this, m_codeBlock->executablePool());
 
     // Use the patch information to link the failure cases back to the original slow case routine.
-    void* slowCaseBegin = reinterpret_cast<char*>(stubInfo->callReturnLocation) - patchOffsetGetByIdSlowCaseCall;
+    CodeLocationLabel slowCaseBegin = stubInfo->callReturnLocation.labelAtOffset(-patchOffsetGetByIdSlowCaseCall);
     patchBuffer.link(failureCases1, slowCaseBegin);
     patchBuffer.link(failureCases2, slowCaseBegin);
 
     // On success return back to the hot patch code, at a point it will perform the store to dest for us.
-    void* hotPathPutResult = reinterpret_cast<char*>(stubInfo->hotPathBegin) + patchOffsetGetByIdPutResult;
-    patchBuffer.link(success, hotPathPutResult);
+    patchBuffer.link(success, stubInfo->hotPathBegin.labelAtOffset(patchOffsetGetByIdPutResult));
 
     // Track the stub we have created so that it will be deleted later.
-    stubInfo->stubRoutine = code;
-
-    // Finally patch the jump to sow case back in the hot path to jump here instead.
-    void* jumpLocation = reinterpret_cast<char*>(stubInfo->hotPathBegin) + patchOffsetGetByIdBranchToSlowCase;
-    Jump::patch(jumpLocation, code);
-}
-
-void JIT::privateCompileGetByIdSelf(StructureStubInfo* stubInfo, Structure* structure, size_t cachedOffset, void* returnAddress)
-{
-    // Check eax is an object of the right Structure.
-    Jump failureCases1 = emitJumpIfNotJSCell(X86::eax);
-    Jump failureCases2 = checkStructure(X86::eax, structure);
+    CodeLocationLabel entryLabel = patchBuffer.finalizeCodeAddendum();
+    stubInfo->stubRoutine = entryLabel;
 
-    // Checks out okay! - getDirectOffset
-    loadPtr(Address(X86::eax, FIELD_OFFSET(JSObject, m_propertyStorage)), X86::eax);
-    loadPtr(Address(X86::eax, cachedOffset * sizeof(JSValuePtr)), X86::eax);
-    ret();
-
-    void* code = m_assembler.executableCopy(m_codeBlock->executablePool());
-    PatchBuffer patchBuffer(code);
-
-    patchBuffer.link(failureCases1, reinterpret_cast<void*>(Interpreter::cti_op_get_by_id_self_fail));
-    patchBuffer.link(failureCases2, reinterpret_cast<void*>(Interpreter::cti_op_get_by_id_self_fail));
-
-    stubInfo->stubRoutine = code;
+    // Finally patch the jump to slow case back in the hot path to jump here instead.
+    CodeLocationJump jumpLocation = stubInfo->hotPathBegin.jumpAtOffset(patchOffsetGetByIdBranchToSlowCase);
+    RepatchBuffer repatchBuffer(m_codeBlock);
+    repatchBuffer.relink(jumpLocation, entryLabel);
 
-    Jump::patch(returnAddress, code);
+    // We don't want to patch more than once - in future go to cti_op_put_by_id_generic.
+    repatchBuffer.relinkCallerToFunction(returnAddress, FunctionPtr(cti_op_get_by_id_array_fail));
 }
 
-void JIT::privateCompileGetByIdProto(StructureStubInfo* stubInfo, Structure* structure, Structure* prototypeStructure, size_t cachedOffset, void* returnAddress, CallFrame* callFrame)
+void JIT::privateCompileGetByIdProto(StructureStubInfo* stubInfo, Structure* structure, Structure* prototypeStructure, const Identifier& ident, const PropertySlot& slot, size_t cachedOffset, ReturnAddressPtr returnAddress, CallFrame* callFrame)
 {
-#if USE(CTI_REPATCH_PIC)
-    // We don't want to patch more than once - in future go to cti_op_put_by_id_generic.
-    Jump::patch(returnAddress, reinterpret_cast<void*>(Interpreter::cti_op_get_by_id_proto_list));
-
     // The prototype object definitely exists (if this stub exists the CodeBlock is referencing a Structure that is
     // referencing the prototype object - let's speculatively load it's table nice and early!)
     JSObject* protoObject = asObject(structure->prototypeForLookup(callFrame));
-    PropertyStorage* protoPropertyStorage = &protoObject->m_propertyStorage;
-    loadPtr(static_cast<void*>(protoPropertyStorage), X86::edx);
 
     // Check eax is an object of the right Structure.
-    Jump failureCases1 = checkStructure(X86::eax, structure);
+    Jump failureCases1 = checkStructure(regT0, structure);
 
     // Check the prototype object's Structure had not changed.
-    Structure** prototypeStructureAddress = &(protoObject->m_structure);
-#if PLATFORM(X86_64)
-    move(ImmPtr(prototypeStructure), X86::ebx);
-    Jump failureCases2 = jnePtr(X86::ebx, AbsoluteAddress(prototypeStructureAddress));
-#else
-    Jump failureCases2 = jnePtr(AbsoluteAddress(prototypeStructureAddress), ImmPtr(prototypeStructure));
-#endif
-
-    // Checks out okay! - getDirectOffset
-    loadPtr(Address(X86::edx, cachedOffset * sizeof(JSValuePtr)), X86::eax);
+    move(TrustedImmPtr(protoObject), regT3);
+    Jump failureCases2 = branchPtr(NotEqual, Address(regT3, JSCell::structureOffset()), TrustedImmPtr(prototypeStructure));
 
+    bool needsStubLink = false;
+    
+    // Checks out okay!
+    if (slot.cachedPropertyType() == PropertySlot::Getter) {
+        needsStubLink = true;
+        compileGetDirectOffset(protoObject, regT1, cachedOffset);
+        JITStubCall stubCall(this, cti_op_get_by_id_getter_stub);
+        stubCall.addArgument(regT1);
+        stubCall.addArgument(regT0);
+        stubCall.addArgument(TrustedImmPtr(stubInfo->callReturnLocation.executableAddress()));
+        stubCall.call();
+    } else if (slot.cachedPropertyType() == PropertySlot::Custom) {
+        needsStubLink = true;
+        JITStubCall stubCall(this, cti_op_get_by_id_custom_stub);
+        stubCall.addArgument(TrustedImmPtr(protoObject));
+        stubCall.addArgument(TrustedImmPtr(FunctionPtr(slot.customGetter()).executableAddress()));
+        stubCall.addArgument(TrustedImmPtr(const_cast<Identifier*>(&ident)));
+        stubCall.addArgument(TrustedImmPtr(stubInfo->callReturnLocation.executableAddress()));
+        stubCall.call();
+    } else
+        compileGetDirectOffset(protoObject, regT0, cachedOffset);
     Jump success = jump();
-
-    void* code = m_assembler.executableCopy(m_codeBlock->executablePool());
-    PatchBuffer patchBuffer(code);
+    LinkBuffer patchBuffer(*m_globalData, this, m_codeBlock->executablePool());
 
     // Use the patch information to link the failure cases back to the original slow case routine.
-    void* slowCaseBegin = reinterpret_cast<char*>(stubInfo->callReturnLocation) - patchOffsetGetByIdSlowCaseCall;
+    CodeLocationLabel slowCaseBegin = stubInfo->callReturnLocation.labelAtOffset(-patchOffsetGetByIdSlowCaseCall);
     patchBuffer.link(failureCases1, slowCaseBegin);
     patchBuffer.link(failureCases2, slowCaseBegin);
 
     // On success return back to the hot patch code, at a point it will perform the store to dest for us.
-    intptr_t successDest = reinterpret_cast<intptr_t>(stubInfo->hotPathBegin) + patchOffsetGetByIdPutResult;
-    patchBuffer.link(success, reinterpret_cast<void*>(successDest));
+    patchBuffer.link(success, stubInfo->hotPathBegin.labelAtOffset(patchOffsetGetByIdPutResult));
 
+    if (needsStubLink) {
+        for (Vector<CallRecord>::iterator iter = m_calls.begin(); iter != m_calls.end(); ++iter) {
+            if (iter->to)
+                patchBuffer.link(iter->from, FunctionPtr(iter->to));
+        }
+    }
     // Track the stub we have created so that it will be deleted later.
-    stubInfo->stubRoutine = code;
+    CodeLocationLabel entryLabel = patchBuffer.finalizeCodeAddendum();
+    stubInfo->stubRoutine = entryLabel;
 
     // Finally patch the jump to slow case back in the hot path to jump here instead.
-    void* jumpLocation = reinterpret_cast<char*>(stubInfo->hotPathBegin) + patchOffsetGetByIdBranchToSlowCase;
-    Jump::patch(jumpLocation, code);
-#else
-    // The prototype object definitely exists (if this stub exists the CodeBlock is referencing a Structure that is
-    // referencing the prototype object - let's speculatively load it's table nice and early!)
-    JSObject* protoObject = asObject(structure->prototypeForLookup(callFrame));
-    PropertyStorage* protoPropertyStorage = &protoObject->m_propertyStorage;
-    loadPtr(protoPropertyStorage, X86::edx);
-
-    // Check eax is an object of the right Structure.
-    Jump failureCases1 = emitJumpIfNotJSCell(X86::eax);
-    Jump failureCases2 = checkStructure(X86::eax, structure);
-
-    // Check the prototype object's Structure had not changed.
-    Structure** prototypeStructureAddress = &(protoObject->m_structure);
-    Jump failureCases3 = jnePtr(AbsoluteAddress(prototypeStructureAddress), ImmPtr(prototypeStructure));
+    CodeLocationJump jumpLocation = stubInfo->hotPathBegin.jumpAtOffset(patchOffsetGetByIdBranchToSlowCase);
+    RepatchBuffer repatchBuffer(m_codeBlock);
+    repatchBuffer.relink(jumpLocation, entryLabel);
 
-    // Checks out okay! - getDirectOffset
-    loadPtr(Address(X86::edx, cachedOffset * sizeof(JSValuePtr)), X86::eax);
-
-    ret();
-
-    void* code = m_assembler.executableCopy(m_codeBlock->executablePool());
-    PatchBuffer patchBuffer(code);
-
-    patchBuffer.link(failureCases1, reinterpret_cast<void*>(Interpreter::cti_op_get_by_id_proto_fail));
-    patchBuffer.link(failureCases2, reinterpret_cast<void*>(Interpreter::cti_op_get_by_id_proto_fail));
-    patchBuffer.link(failureCases3, reinterpret_cast<void*>(Interpreter::cti_op_get_by_id_proto_fail));
-
-    stubInfo->stubRoutine = code;
-
-    Jump::patch(returnAddress, code);
-#endif
+    // We don't want to patch more than once - in future go to cti_op_put_by_id_generic.
+    repatchBuffer.relinkCallerToFunction(returnAddress, FunctionPtr(cti_op_get_by_id_proto_list));
 }
 
-#if USE(CTI_REPATCH_PIC)
-void JIT::privateCompileGetByIdSelfList(StructureStubInfo* stubInfo, PolymorphicAccessStructureList* polymorphicStructures, int currentIndex, Structure* structure, size_t cachedOffset)
+void JIT::privateCompileGetByIdSelfList(StructureStubInfo* stubInfo, PolymorphicAccessStructureList* polymorphicStructures, int currentIndex, Structure* structure, const Identifier& ident, const PropertySlot& slot, size_t cachedOffset)
 {
-    Jump failureCase = checkStructure(X86::eax, structure);
-    loadPtr(Address(X86::eax, FIELD_OFFSET(JSObject, m_propertyStorage)), X86::eax);
-    loadPtr(Address(X86::eax, cachedOffset * sizeof(JSValuePtr)), X86::eax);
+    Jump failureCase = checkStructure(regT0, structure);
+    bool needsStubLink = false;
+    if (slot.cachedPropertyType() == PropertySlot::Getter) {
+        needsStubLink = true;
+        compileGetDirectOffset(regT0, regT1, structure, cachedOffset);
+        JITStubCall stubCall(this, cti_op_get_by_id_getter_stub);
+        stubCall.addArgument(regT1);
+        stubCall.addArgument(regT0);
+        stubCall.addArgument(TrustedImmPtr(stubInfo->callReturnLocation.executableAddress()));
+        stubCall.call();
+    } else if (slot.cachedPropertyType() == PropertySlot::Custom) {
+        needsStubLink = true;
+        JITStubCall stubCall(this, cti_op_get_by_id_custom_stub);
+        stubCall.addArgument(regT0);
+        stubCall.addArgument(TrustedImmPtr(FunctionPtr(slot.customGetter()).executableAddress()));
+        stubCall.addArgument(TrustedImmPtr(const_cast<Identifier*>(&ident)));
+        stubCall.addArgument(TrustedImmPtr(stubInfo->callReturnLocation.executableAddress()));
+        stubCall.call();
+    } else
+        compileGetDirectOffset(regT0, regT0, structure, cachedOffset);
     Jump success = jump();
 
-    void* code = m_assembler.executableCopy(m_codeBlock->executablePool());
-    ASSERT(code);
-    PatchBuffer patchBuffer(code);
+    LinkBuffer patchBuffer(*m_globalData, this, m_codeBlock->executablePool());
+
+    if (needsStubLink) {
+        for (Vector<CallRecord>::iterator iter = m_calls.begin(); iter != m_calls.end(); ++iter) {
+            if (iter->to)
+                patchBuffer.link(iter->from, FunctionPtr(iter->to));
+        }
+    }
 
     // Use the patch information to link the failure cases back to the original slow case routine.
-    void* lastProtoBegin = polymorphicStructures->list[currentIndex - 1].stubRoutine;
+    CodeLocationLabel lastProtoBegin = polymorphicStructures->list[currentIndex - 1].stubRoutine;
     if (!lastProtoBegin)
-        lastProtoBegin = reinterpret_cast<char*>(stubInfo->callReturnLocation) - patchOffsetGetByIdSlowCaseCall;
+        lastProtoBegin = stubInfo->callReturnLocation.labelAtOffset(-patchOffsetGetByIdSlowCaseCall);
 
     patchBuffer.link(failureCase, lastProtoBegin);
 
     // On success return back to the hot patch code, at a point it will perform the store to dest for us.
-    intptr_t successDest = reinterpret_cast<intptr_t>(stubInfo->hotPathBegin) + patchOffsetGetByIdPutResult;
-    patchBuffer.link(success, reinterpret_cast<void*>(successDest));
+    patchBuffer.link(success, stubInfo->hotPathBegin.labelAtOffset(patchOffsetGetByIdPutResult));
+
+    CodeLocationLabel entryLabel = patchBuffer.finalizeCodeAddendum();
 
-    structure->ref();
-    polymorphicStructures->list[currentIndex].set(code, structure);
+    polymorphicStructures->list[currentIndex].set(*m_globalData, m_codeBlock->ownerExecutable(), entryLabel, structure);
 
     // Finally patch the jump to slow case back in the hot path to jump here instead.
-    void* jumpLocation = reinterpret_cast<char*>(stubInfo->hotPathBegin) + patchOffsetGetByIdBranchToSlowCase;
-    Jump::patch(jumpLocation, code);
+    CodeLocationJump jumpLocation = stubInfo->hotPathBegin.jumpAtOffset(patchOffsetGetByIdBranchToSlowCase);
+    RepatchBuffer repatchBuffer(m_codeBlock);
+    repatchBuffer.relink(jumpLocation, entryLabel);
 }
 
-void JIT::privateCompileGetByIdProtoList(StructureStubInfo* stubInfo, PolymorphicAccessStructureList* prototypeStructures, int currentIndex, Structure* structure, Structure* prototypeStructure, size_t cachedOffset, CallFrame* callFrame)
+void JIT::privateCompileGetByIdProtoList(StructureStubInfo* stubInfo, PolymorphicAccessStructureList* prototypeStructures, int currentIndex, Structure* structure, Structure* prototypeStructure, const Identifier& ident, const PropertySlot& slot, size_t cachedOffset, CallFrame* callFrame)
 {
     // The prototype object definitely exists (if this stub exists the CodeBlock is referencing a Structure that is
     // referencing the prototype object - let's speculatively load it's table nice and early!)
     JSObject* protoObject = asObject(structure->prototypeForLookup(callFrame));
-    PropertyStorage* protoPropertyStorage = &protoObject->m_propertyStorage;
-    loadPtr(protoPropertyStorage, X86::edx);
 
     // Check eax is an object of the right Structure.
-    Jump failureCases1 = checkStructure(X86::eax, structure);
+    Jump failureCases1 = checkStructure(regT0, structure);
 
     // Check the prototype object's Structure had not changed.
-    Structure** prototypeStructureAddress = &(protoObject->m_structure);
-#if PLATFORM(X86_64)
-    move(ImmPtr(prototypeStructure), X86::ebx);
-    Jump failureCases2 = jnePtr(X86::ebx, AbsoluteAddress(prototypeStructureAddress));
-#else
-    Jump failureCases2 = jnePtr(AbsoluteAddress(prototypeStructureAddress), ImmPtr(prototypeStructure));
-#endif
-
-    // Checks out okay! - getDirectOffset
-    loadPtr(Address(X86::edx, cachedOffset * sizeof(JSValuePtr)), X86::eax);
+    move(TrustedImmPtr(protoObject), regT3);
+    Jump failureCases2 = branchPtr(NotEqual, Address(regT3, JSCell::structureOffset()), TrustedImmPtr(prototypeStructure));
+
+    // Checks out okay!
+    bool needsStubLink = false;
+    if (slot.cachedPropertyType() == PropertySlot::Getter) {
+        needsStubLink = true;
+        compileGetDirectOffset(protoObject, regT1, cachedOffset);
+        JITStubCall stubCall(this, cti_op_get_by_id_getter_stub);
+        stubCall.addArgument(regT1);
+        stubCall.addArgument(regT0);
+        stubCall.addArgument(TrustedImmPtr(stubInfo->callReturnLocation.executableAddress()));
+        stubCall.call();
+    } else if (slot.cachedPropertyType() == PropertySlot::Custom) {
+        needsStubLink = true;
+        JITStubCall stubCall(this, cti_op_get_by_id_custom_stub);
+        stubCall.addArgument(TrustedImmPtr(protoObject));
+        stubCall.addArgument(TrustedImmPtr(FunctionPtr(slot.customGetter()).executableAddress()));
+        stubCall.addArgument(TrustedImmPtr(const_cast<Identifier*>(&ident)));
+        stubCall.addArgument(TrustedImmPtr(stubInfo->callReturnLocation.executableAddress()));
+        stubCall.call();
+    } else
+        compileGetDirectOffset(protoObject, regT0, cachedOffset);
 
     Jump success = jump();
 
-    void* code = m_assembler.executableCopy(m_codeBlock->executablePool());
-    PatchBuffer patchBuffer(code);
+    LinkBuffer patchBuffer(*m_globalData, this, m_codeBlock->executablePool());
+
+    if (needsStubLink) {
+        for (Vector<CallRecord>::iterator iter = m_calls.begin(); iter != m_calls.end(); ++iter) {
+            if (iter->to)
+                patchBuffer.link(iter->from, FunctionPtr(iter->to));
+        }
+    }
 
     // Use the patch information to link the failure cases back to the original slow case routine.
-    void* lastProtoBegin = prototypeStructures->list[currentIndex - 1].stubRoutine;
+    CodeLocationLabel lastProtoBegin = prototypeStructures->list[currentIndex - 1].stubRoutine;
     patchBuffer.link(failureCases1, lastProtoBegin);
     patchBuffer.link(failureCases2, lastProtoBegin);
 
     // On success return back to the hot patch code, at a point it will perform the store to dest for us.
-    intptr_t successDest = reinterpret_cast<intptr_t>(stubInfo->hotPathBegin) + patchOffsetGetByIdPutResult;
-    patchBuffer.link(success, reinterpret_cast<void*>(successDest));
+    patchBuffer.link(success, stubInfo->hotPathBegin.labelAtOffset(patchOffsetGetByIdPutResult));
 
-    structure->ref();
-    prototypeStructure->ref();
-    prototypeStructures->list[currentIndex].set(code, structure, prototypeStructure);
+    CodeLocationLabel entryLabel = patchBuffer.finalizeCodeAddendum();
+    prototypeStructures->list[currentIndex].set(*m_globalData, m_codeBlock->ownerExecutable(), entryLabel, structure, prototypeStructure);
 
     // Finally patch the jump to slow case back in the hot path to jump here instead.
-    void* jumpLocation = reinterpret_cast<char*>(stubInfo->hotPathBegin) + patchOffsetGetByIdBranchToSlowCase;
-    Jump::patch(jumpLocation, code);
+    CodeLocationJump jumpLocation = stubInfo->hotPathBegin.jumpAtOffset(patchOffsetGetByIdBranchToSlowCase);
+    RepatchBuffer repatchBuffer(m_codeBlock);
+    repatchBuffer.relink(jumpLocation, entryLabel);
 }
 
-void JIT::privateCompileGetByIdChainList(StructureStubInfo* stubInfo, PolymorphicAccessStructureList* prototypeStructures, int currentIndex, Structure* structure, StructureChain* chain, size_t count, size_t cachedOffset, CallFrame* callFrame)
+void JIT::privateCompileGetByIdChainList(StructureStubInfo* stubInfo, PolymorphicAccessStructureList* prototypeStructures, int currentIndex, Structure* structure, StructureChain* chain, size_t count, const Identifier& ident, const PropertySlot& slot, size_t cachedOffset, CallFrame* callFrame)
 {
     ASSERT(count);
-    
     JumpList bucketsOfFail;
 
     // Check eax is an object of the right Structure.
-    Jump baseObjectCheck = checkStructure(X86::eax, structure);
+    Jump baseObjectCheck = checkStructure(regT0, structure);
     bucketsOfFail.append(baseObjectCheck);
 
     Structure* currStructure = structure;
-    RefPtr<Structure>* chainEntries = chain->head();
+    WriteBarrier<Structure>* it = chain->head();
     JSObject* protoObject = 0;
-    for (unsigned i = 0; i < count; ++i) {
+    for (unsigned i = 0; i < count; ++i, ++it) {
         protoObject = asObject(currStructure->prototypeForLookup(callFrame));
-        currStructure = chainEntries[i].get();
-
-        // Check the prototype object's Structure had not changed.
-        Structure** prototypeStructureAddress = &(protoObject->m_structure);
-#if PLATFORM(X86_64)
-        move(ImmPtr(currStructure), X86::ebx);
-        bucketsOfFail.append(jnePtr(X86::ebx, AbsoluteAddress(prototypeStructureAddress)));
-#else
-        bucketsOfFail.append(jnePtr(AbsoluteAddress(prototypeStructureAddress), ImmPtr(currStructure)));
-#endif
+        currStructure = it->get();
+        testPrototype(protoObject, bucketsOfFail);
     }
     ASSERT(protoObject);
-
-    PropertyStorage* protoPropertyStorage = &protoObject->m_propertyStorage;
-    loadPtr(protoPropertyStorage, X86::edx);
-    loadPtr(Address(X86::edx, cachedOffset * sizeof(JSValuePtr)), X86::eax);
+    
+    bool needsStubLink = false;
+    if (slot.cachedPropertyType() == PropertySlot::Getter) {
+        needsStubLink = true;
+        compileGetDirectOffset(protoObject, regT1, cachedOffset);
+        JITStubCall stubCall(this, cti_op_get_by_id_getter_stub);
+        stubCall.addArgument(regT1);
+        stubCall.addArgument(regT0);
+        stubCall.addArgument(TrustedImmPtr(stubInfo->callReturnLocation.executableAddress()));
+        stubCall.call();
+    } else if (slot.cachedPropertyType() == PropertySlot::Custom) {
+        needsStubLink = true;
+        JITStubCall stubCall(this, cti_op_get_by_id_custom_stub);
+        stubCall.addArgument(TrustedImmPtr(protoObject));
+        stubCall.addArgument(TrustedImmPtr(FunctionPtr(slot.customGetter()).executableAddress()));
+        stubCall.addArgument(TrustedImmPtr(const_cast<Identifier*>(&ident)));
+        stubCall.addArgument(TrustedImmPtr(stubInfo->callReturnLocation.executableAddress()));
+        stubCall.call();
+    } else
+        compileGetDirectOffset(protoObject, regT0, cachedOffset);
     Jump success = jump();
 
-    void* code = m_assembler.executableCopy(m_codeBlock->executablePool());
-    PatchBuffer patchBuffer(code);
+    LinkBuffer patchBuffer(*m_globalData, this, m_codeBlock->executablePool());
+    
+    if (needsStubLink) {
+        for (Vector<CallRecord>::iterator iter = m_calls.begin(); iter != m_calls.end(); ++iter) {
+            if (iter->to)
+                patchBuffer.link(iter->from, FunctionPtr(iter->to));
+        }
+    }
 
     // Use the patch information to link the failure cases back to the original slow case routine.
-    void* lastProtoBegin = prototypeStructures->list[currentIndex - 1].stubRoutine;
+    CodeLocationLabel lastProtoBegin = prototypeStructures->list[currentIndex - 1].stubRoutine;
 
     patchBuffer.link(bucketsOfFail, lastProtoBegin);
 
     // On success return back to the hot patch code, at a point it will perform the store to dest for us.
-    intptr_t successDest = reinterpret_cast<intptr_t>(stubInfo->hotPathBegin) + patchOffsetGetByIdPutResult;
-    patchBuffer.link(success, reinterpret_cast<void*>(successDest));
+    patchBuffer.link(success, stubInfo->hotPathBegin.labelAtOffset(patchOffsetGetByIdPutResult));
+
+    CodeLocationLabel entryLabel = patchBuffer.finalizeCodeAddendum();
 
     // Track the stub we have created so that it will be deleted later.
-    structure->ref();
-    chain->ref();
-    prototypeStructures->list[currentIndex].set(code, structure, chain);
+    prototypeStructures->list[currentIndex].set(callFrame->globalData(), m_codeBlock->ownerExecutable(), entryLabel, structure, chain);
 
     // Finally patch the jump to slow case back in the hot path to jump here instead.
-    void* jumpLocation = reinterpret_cast<char*>(stubInfo->hotPathBegin) + patchOffsetGetByIdBranchToSlowCase;
-    Jump::patch(jumpLocation, code);
+    CodeLocationJump jumpLocation = stubInfo->hotPathBegin.jumpAtOffset(patchOffsetGetByIdBranchToSlowCase);
+    RepatchBuffer repatchBuffer(m_codeBlock);
+    repatchBuffer.relink(jumpLocation, entryLabel);
 }
-#endif
 
-void JIT::privateCompileGetByIdChain(StructureStubInfo* stubInfo, Structure* structure, StructureChain* chain, size_t count, size_t cachedOffset, void* returnAddress, CallFrame* callFrame)
+void JIT::privateCompileGetByIdChain(StructureStubInfo* stubInfo, Structure* structure, StructureChain* chain, size_t count, const Identifier& ident, const PropertySlot& slot, size_t cachedOffset, ReturnAddressPtr returnAddress, CallFrame* callFrame)
 {
-#if USE(CTI_REPATCH_PIC)
-    // We don't want to patch more than once - in future go to cti_op_put_by_id_generic.
-    Jump::patch(returnAddress, reinterpret_cast<void*>(Interpreter::cti_op_get_by_id_proto_list));
-
     ASSERT(count);
-    
+
     JumpList bucketsOfFail;
 
     // Check eax is an object of the right Structure.
-    bucketsOfFail.append(checkStructure(X86::eax, structure));
+    bucketsOfFail.append(checkStructure(regT0, structure));
 
     Structure* currStructure = structure;
-    RefPtr<Structure>* chainEntries = chain->head();
+    WriteBarrier<Structure>* it = chain->head();
     JSObject* protoObject = 0;
-    for (unsigned i = 0; i < count; ++i) {
+    for (unsigned i = 0; i < count; ++i, ++it) {
         protoObject = asObject(currStructure->prototypeForLookup(callFrame));
-        currStructure = chainEntries[i].get();
-
-        // Check the prototype object's Structure had not changed.
-        Structure** prototypeStructureAddress = &(protoObject->m_structure);
-#if PLATFORM(X86_64)
-        move(ImmPtr(currStructure), X86::ebx);
-        bucketsOfFail.append(jnePtr(X86::ebx, AbsoluteAddress(prototypeStructureAddress)));
-#else
-        bucketsOfFail.append(jnePtr(AbsoluteAddress(prototypeStructureAddress), ImmPtr(currStructure)));
-#endif
+        currStructure = it->get();
+        testPrototype(protoObject, bucketsOfFail);
     }
     ASSERT(protoObject);
 
-    PropertyStorage* protoPropertyStorage = &protoObject->m_propertyStorage;
-    loadPtr(protoPropertyStorage, X86::edx);
-    loadPtr(Address(X86::edx, cachedOffset * sizeof(JSValuePtr)), X86::eax);
+    bool needsStubLink = false;
+    if (slot.cachedPropertyType() == PropertySlot::Getter) {
+        needsStubLink = true;
+        compileGetDirectOffset(protoObject, regT1, cachedOffset);
+        JITStubCall stubCall(this, cti_op_get_by_id_getter_stub);
+        stubCall.addArgument(regT1);
+        stubCall.addArgument(regT0);
+        stubCall.addArgument(TrustedImmPtr(stubInfo->callReturnLocation.executableAddress()));
+        stubCall.call();
+    } else if (slot.cachedPropertyType() == PropertySlot::Custom) {
+        needsStubLink = true;
+        JITStubCall stubCall(this, cti_op_get_by_id_custom_stub);
+        stubCall.addArgument(TrustedImmPtr(protoObject));
+        stubCall.addArgument(TrustedImmPtr(FunctionPtr(slot.customGetter()).executableAddress()));
+        stubCall.addArgument(TrustedImmPtr(const_cast<Identifier*>(&ident)));
+        stubCall.addArgument(TrustedImmPtr(stubInfo->callReturnLocation.executableAddress()));
+        stubCall.call();
+    } else
+        compileGetDirectOffset(protoObject, regT0, cachedOffset);
     Jump success = jump();
 
-    void* code = m_assembler.executableCopy(m_codeBlock->executablePool());
-    PatchBuffer patchBuffer(code);
+    LinkBuffer patchBuffer(*m_globalData, this, m_codeBlock->executablePool());
 
-    // Use the patch information to link the failure cases back to the original slow case routine.
-    void* slowCaseBegin = reinterpret_cast<char*>(stubInfo->callReturnLocation) - patchOffsetGetByIdSlowCaseCall;
+    if (needsStubLink) {
+        for (Vector<CallRecord>::iterator iter = m_calls.begin(); iter != m_calls.end(); ++iter) {
+            if (iter->to)
+                patchBuffer.link(iter->from, FunctionPtr(iter->to));
+        }
+    }
 
-    patchBuffer.link(bucketsOfFail, slowCaseBegin);
+    // Use the patch information to link the failure cases back to the original slow case routine.
+    patchBuffer.link(bucketsOfFail, stubInfo->callReturnLocation.labelAtOffset(-patchOffsetGetByIdSlowCaseCall));
 
     // On success return back to the hot patch code, at a point it will perform the store to dest for us.
-    intptr_t successDest = reinterpret_cast<intptr_t>(stubInfo->hotPathBegin) + patchOffsetGetByIdPutResult;
-    patchBuffer.link(success, reinterpret_cast<void*>(successDest));
+    patchBuffer.link(success, stubInfo->hotPathBegin.labelAtOffset(patchOffsetGetByIdPutResult));
 
     // Track the stub we have created so that it will be deleted later.
-    stubInfo->stubRoutine = code;
+    CodeLocationLabel entryLabel = patchBuffer.finalizeCodeAddendum();
+    stubInfo->stubRoutine = entryLabel;
 
     // Finally patch the jump to slow case back in the hot path to jump here instead.
-    void* jumpLocation = reinterpret_cast<char*>(stubInfo->hotPathBegin) + patchOffsetGetByIdBranchToSlowCase;
-    Jump::patch(jumpLocation, code);
-#else
-    ASSERT(count);
-    
-    JumpList bucketsOfFail;
+    CodeLocationJump jumpLocation = stubInfo->hotPathBegin.jumpAtOffset(patchOffsetGetByIdBranchToSlowCase);
+    RepatchBuffer repatchBuffer(m_codeBlock);
+    repatchBuffer.relink(jumpLocation, entryLabel);
 
-    // Check eax is an object of the right Structure.
-    bucketsOfFail.append(emitJumpIfNotJSCell(X86::eax));
-    bucketsOfFail.append(checkStructure(X86::eax, structure));
-
-    Structure* currStructure = structure;
-    RefPtr<Structure>* chainEntries = chain->head();
-    JSObject* protoObject = 0;
-    for (unsigned i = 0; i < count; ++i) {
-        protoObject = asObject(currStructure->prototypeForLookup(callFrame));
-        currStructure = chainEntries[i].get();
-
-        // Check the prototype object's Structure had not changed.
-        Structure** prototypeStructureAddress = &(protoObject->m_structure);
-#if PLATFORM(X86_64)
-        move(ImmPtr(currStructure), X86::ebx);
-        bucketsOfFail.append(jnePtr(X86::ebx, AbsoluteAddress(prototypeStructureAddress)));
-#else
-        bucketsOfFail.append(jnePtr(AbsoluteAddress(prototypeStructureAddress), ImmPtr(currStructure)));
-#endif
-    }
-    ASSERT(protoObject);
+    // We don't want to patch more than once - in future go to cti_op_put_by_id_generic.
+    repatchBuffer.relinkCallerToFunction(returnAddress, FunctionPtr(cti_op_get_by_id_proto_list));
+}
 
-    PropertyStorage* protoPropertyStorage = &protoObject->m_propertyStorage;
-    loadPtr(protoPropertyStorage, X86::edx);
-    loadPtr(Address(X86::edx, cachedOffset * sizeof(JSValuePtr)), X86::eax);
-    ret();
+/* ------------------------------ END: !ENABLE / ENABLE(JIT_OPTIMIZE_PROPERTY_ACCESS) ------------------------------ */
 
-    void* code = m_assembler.executableCopy(m_codeBlock->executablePool());
+#endif // !ENABLE(JIT_OPTIMIZE_PROPERTY_ACCESS)
 
-    patchBuffer.link(bucketsOfFail, reinterpret_cast<void*>(Interpreter::cti_op_get_by_id_proto_fail));
+#endif // USE(JSVALUE64)
 
-    stubInfo->stubRoutine = code;
+void JIT::testPrototype(JSValue prototype, JumpList& failureCases)
+{
+    if (prototype.isNull())
+        return;
 
-    Jump::patch(returnAddress, code);
-#endif
+    ASSERT(prototype.isCell());
+    move(TrustedImmPtr(prototype.asCell()), regT3);
+    failureCases.append(branchPtr(NotEqual, Address(regT3, JSCell::structureOffset()), TrustedImmPtr(prototype.asCell()->structure())));
 }
 
-void JIT::privateCompilePutByIdReplace(StructureStubInfo* stubInfo, Structure* structure, size_t cachedOffset, void* returnAddress)
+void JIT::patchMethodCallProto(JSGlobalData& globalData, CodeBlock* codeBlock, MethodCallLinkInfo& methodCallLinkInfo, JSObjectWithGlobalObject* callee, Structure* structure, JSObject* proto, ReturnAddressPtr returnAddress)
 {
-    // Check eax is an object of the right Structure.
-    Jump failureCases1 = emitJumpIfNotJSCell(X86::eax);
-    Jump failureCases2 = checkStructure(X86::eax, structure);
-
-    // checks out okay! - putDirectOffset
-    loadPtr(Address(X86::eax, FIELD_OFFSET(JSObject, m_propertyStorage)), X86::eax);
-    storePtr(X86::edx, Address(X86::eax, cachedOffset * sizeof(JSValuePtr)));
-    ret();
-
-    void* code = m_assembler.executableCopy(m_codeBlock->executablePool());
-    PatchBuffer patchBuffer(code);
+    RepatchBuffer repatchBuffer(codeBlock);
     
-    patchBuffer.link(failureCases1, reinterpret_cast<void*>(Interpreter::cti_op_put_by_id_fail));
-    patchBuffer.link(failureCases2, reinterpret_cast<void*>(Interpreter::cti_op_put_by_id_fail));
-
-    stubInfo->stubRoutine = code;
+    ASSERT(!methodCallLinkInfo.cachedStructure);
+    CodeLocationDataLabelPtr structureLocation = methodCallLinkInfo.cachedStructure.location();
+    methodCallLinkInfo.cachedStructure.set(globalData, structureLocation, codeBlock->ownerExecutable(), structure);
     
-    Jump::patch(returnAddress, code);
+    Structure* prototypeStructure = proto->structure();
+    methodCallLinkInfo.cachedPrototypeStructure.set(globalData, structureLocation.dataLabelPtrAtOffset(patchOffsetMethodCheckProtoStruct), codeBlock->ownerExecutable(), prototypeStructure);
+    methodCallLinkInfo.cachedPrototype.set(globalData, structureLocation.dataLabelPtrAtOffset(patchOffsetMethodCheckProtoObj), codeBlock->ownerExecutable(), proto);
+    methodCallLinkInfo.cachedFunction.set(globalData, structureLocation.dataLabelPtrAtOffset(patchOffsetMethodCheckPutFunction), codeBlock->ownerExecutable(), callee);
+    repatchBuffer.relinkCallerToFunction(returnAddress, FunctionPtr(cti_op_get_by_id));
 }
 
-#endif
-
 } // namespace JSC
 
 #endif // ENABLE(JIT)