]> git.saurik.com Git - apple/javascriptcore.git/blobdiff - jit/JITOpcodes32_64.cpp
JavaScriptCore-7600.1.4.15.12.tar.gz
[apple/javascriptcore.git] / jit / JITOpcodes32_64.cpp
index 4836a66b5791cb2bbf90ae0569b5b4241d3dd736..a540d6e8a89c668ec3421d5faff0759af292c648 100644 (file)
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2009, 2012 Apple Inc. All rights reserved.
+ * Copyright (C) 2009, 2012, 2013, 2014 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Patrick Gansterer <paroga@paroga.com>
  *
  * Redistribution and use in source and binary forms, with or without
 #if USE(JSVALUE32_64)
 #include "JIT.h"
 
+#include "CCallHelpers.h"
+#include "Debugger.h"
 #include "JITInlines.h"
-#include "JITStubCall.h"
 #include "JSArray.h"
 #include "JSCell.h"
 #include "JSFunction.h"
 #include "JSPropertyNameIterator.h"
 #include "JSVariableObject.h"
 #include "LinkBuffer.h"
+#include "MaxFrameExtentForSlowPathCall.h"
+#include "SlowPathCall.h"
+#include "VirtualRegister.h"
 
 namespace JSC {
 
@@ -45,139 +49,91 @@ JIT::CodeRef JIT::privateCompileCTINativeCall(VM* vm, NativeFunction func)
 {
     Call nativeCall;
 
+    emitFunctionPrologue();
     emitPutImmediateToCallFrameHeader(0, JSStack::CodeBlock);
     storePtr(callFrameRegister, &m_vm->topCallFrame);
 
 #if CPU(X86)
     // Load caller frame's scope chain into this callframe so that whatever we call can
     // get to its global data.
-    emitGetFromCallFrameHeaderPtr(JSStack::CallerFrame, regT0);
+    emitGetCallerFrameFromCallFrameHeaderPtr(regT0);
     emitGetFromCallFrameHeaderPtr(JSStack::ScopeChain, regT1, regT0);
     emitPutCellToCallFrameHeader(regT1, JSStack::ScopeChain);
 
-    peek(regT1);
-    emitPutToCallFrameHeader(regT1, JSStack::ReturnPC);
-
     // Calling convention:      f(ecx, edx, ...);
     // Host function signature: f(ExecState*);
     move(callFrameRegister, X86Registers::ecx);
 
-    subPtr(TrustedImm32(16 - sizeof(void*)), stackPointerRegister); // Align stack after call.
-
-    move(regT0, callFrameRegister); // Eagerly restore caller frame register to avoid loading from stack.
+    subPtr(TrustedImm32(8), stackPointerRegister); // Align stack for call.
+    storePtr(X86Registers::ecx, Address(stackPointerRegister));
 
     // call the function
     nativeCall = call();
 
-    addPtr(TrustedImm32(16 - sizeof(void*)), stackPointerRegister);
+    addPtr(TrustedImm32(8), stackPointerRegister);
 
-#elif CPU(ARM)
-    // Load caller frame's scope chain into this callframe so that whatever we call can
-    // get to its global data.
-    emitGetFromCallFrameHeaderPtr(JSStack::CallerFrame, regT2);
+#elif CPU(ARM) || CPU(SH4) || CPU(MIPS)
+    // Load caller frame's scope chain into this callframe so that whatever we call can get to its global data.
+    emitGetCallerFrameFromCallFrameHeaderPtr(regT2);
     emitGetFromCallFrameHeaderPtr(JSStack::ScopeChain, regT1, regT2);
     emitPutCellToCallFrameHeader(regT1, JSStack::ScopeChain);
 
-    preserveReturnAddressAfterCall(regT3); // Callee preserved
-    emitPutToCallFrameHeader(regT3, JSStack::ReturnPC);
-
-    // Calling convention:      f(r0 == regT0, r1 == regT1, ...);
-    // Host function signature: f(ExecState*);
-    move(callFrameRegister, ARMRegisters::r0);
-
-    emitGetFromCallFrameHeaderPtr(JSStack::Callee, ARMRegisters::r1);
-    move(regT2, callFrameRegister); // Eagerly restore caller frame register to avoid loading from stack.
-    loadPtr(Address(ARMRegisters::r1, OBJECT_OFFSETOF(JSFunction, m_executable)), regT2);
-
-    // call the function
-    nativeCall = call();
-
-    restoreReturnAddressBeforeReturn(regT3);
-
-#elif CPU(MIPS)
-    // Load caller frame's scope chain into this callframe so that whatever we call can
-    // get to its global data.
-    emitGetFromCallFrameHeaderPtr(JSStack::CallerFrame, regT0);
-    emitGetFromCallFrameHeaderPtr(JSStack::ScopeChain, regT1, regT0);
-    emitPutCellToCallFrameHeader(regT1, JSStack::ScopeChain);
-
-    preserveReturnAddressAfterCall(regT3); // Callee preserved
-    emitPutToCallFrameHeader(regT3, JSStack::ReturnPC);
-
-    // Calling convention:      f(a0, a1, a2, a3);
-    // Host function signature: f(ExecState*);
-
-    // Allocate stack space for 16 bytes (8-byte aligned)
-    // 16 bytes (unused) for 4 arguments
+#if CPU(MIPS)
+    // Allocate stack space for (unused) 16 bytes (8-byte aligned) for 4 arguments.
     subPtr(TrustedImm32(16), stackPointerRegister);
+#endif
 
-    // Setup arg0
-    move(callFrameRegister, MIPSRegisters::a0);
+    // Calling convention is f(argumentGPR0, argumentGPR1, ...).
+    // Host function signature is f(ExecState*).
+    move(callFrameRegister, argumentGPR0);
+
+    emitGetFromCallFrameHeaderPtr(JSStack::Callee, argumentGPR1);
+    loadPtr(Address(argumentGPR1, OBJECT_OFFSETOF(JSFunction, m_executable)), regT2);
 
-    // Call
-    emitGetFromCallFrameHeaderPtr(JSStack::Callee, MIPSRegisters::a2);
-    loadPtr(Address(MIPSRegisters::a2, OBJECT_OFFSETOF(JSFunction, m_executable)), regT2);
-    move(regT0, callFrameRegister); // Eagerly restore caller frame register to avoid loading from stack.
-    
     // call the function
     nativeCall = call();
 
+#if CPU(MIPS)
     // Restore stack space
     addPtr(TrustedImm32(16), stackPointerRegister);
-
-    restoreReturnAddressBeforeReturn(regT3);
-#elif CPU(SH4)
-    // Load caller frame's scope chain into this callframe so that whatever we call can
-    // get to its global data.
-    emitGetFromCallFrameHeaderPtr(JSStack::CallerFrame, regT2);
-    emitGetFromCallFrameHeaderPtr(JSStack::ScopeChain, regT1, regT2);
-    emitPutCellToCallFrameHeader(regT1, JSStack::ScopeChain);
-
-    preserveReturnAddressAfterCall(regT3); // Callee preserved
-    emitPutToCallFrameHeader(regT3, JSStack::ReturnPC);
-
-    // Calling convention: f(r0 == regT4, r1 == regT5, ...);
-    // Host function signature: f(ExecState*);
-    move(callFrameRegister, regT4);
-
-    emitGetFromCallFrameHeaderPtr(JSStack::Callee, regT5);
-    move(regT2, callFrameRegister); // Eagerly restore caller frame register to avoid loading from stack.
-    loadPtr(Address(regT5, OBJECT_OFFSETOF(JSFunction, m_executable)), regT2);
-
-    // call the function
-    nativeCall = call();
+#endif
 
     restoreReturnAddressBeforeReturn(regT3);
 #else
 #error "JIT not supported on this platform."
-    breakpoint();
+    abortWithReason(JITNotSupported);
 #endif // CPU(X86)
 
     // Check for an exception
-    Jump sawException = branch32(NotEqual, AbsoluteAddress(reinterpret_cast<char*>(&vm->exception) + OBJECT_OFFSETOF(JSValue, u.asBits.tag)), TrustedImm32(JSValue::EmptyValueTag));
+    Jump sawException = branch32(NotEqual, AbsoluteAddress(reinterpret_cast<char*>(vm->addressOfException()) + OBJECT_OFFSETOF(JSValue, u.asBits.tag)), TrustedImm32(JSValue::EmptyValueTag)); 
 
+    emitFunctionEpilogue();
     // Return.
     ret();
 
     // Handle an exception
     sawException.link(this);
 
-    // Grab the return address.
-    preserveReturnAddressAfterCall(regT1);
-
-    move(TrustedImmPtr(&vm->exceptionLocation), regT2);
-    storePtr(regT1, regT2);
-    poke(callFrameRegister, OBJECT_OFFSETOF(struct JITStackFrame, callFrame) / sizeof(void*));
-    
     storePtr(callFrameRegister, &m_vm->topCallFrame);
-    // Set the return address.
-    move(TrustedImmPtr(FunctionPtr(ctiVMThrowTrampoline).value()), regT1);
-    restoreReturnAddressBeforeReturn(regT1);
 
-    ret();
+#if CPU(X86)
+    addPtr(TrustedImm32(-4), stackPointerRegister);
+    loadPtr(Address(callFrameRegister), X86Registers::ecx);
+    push(X86Registers::ecx);
+#else
+    loadPtr(Address(callFrameRegister), argumentGPR0);
+#endif
+    move(TrustedImmPtr(FunctionPtr(operationVMHandleException).value()), regT3);
+    call(regT3);
+
+#if CPU(X86)
+    addPtr(TrustedImm32(8), stackPointerRegister);
+#endif
+
+    jumpToExceptionHandler();
 
     // All trampolines constructed! copy the code, link up calls, and set the pointers on the Machine object.
-    LinkBuffer patchBuffer(*m_vm, this, GLOBAL_THUNK_ID);
+    LinkBuffer patchBuffer(*m_vm, *this, GLOBAL_THUNK_ID);
 
     patchBuffer.link(nativeCall, FunctionPtr(func));
     return FINALIZE_CODE(patchBuffer, ("JIT CTI native call"));
@@ -185,23 +141,32 @@ JIT::CodeRef JIT::privateCompileCTINativeCall(VM* vm, NativeFunction func)
 
 void JIT::emit_op_mov(Instruction* currentInstruction)
 {
-    unsigned dst = currentInstruction[1].u.operand;
-    unsigned src = currentInstruction[2].u.operand;
-
+    int dst = currentInstruction[1].u.operand;
+    int src = currentInstruction[2].u.operand;
+    
     if (m_codeBlock->isConstantRegisterIndex(src))
         emitStore(dst, getConstantOperand(src));
     else {
         emitLoad(src, regT1, regT0);
         emitStore(dst, regT1, regT0);
-        map(m_bytecodeOffset + OPCODE_LENGTH(op_mov), dst, regT1, regT0);
     }
 }
 
+void JIT::emit_op_captured_mov(Instruction* currentInstruction)
+{
+    int dst = currentInstruction[1].u.operand;
+    int src = currentInstruction[2].u.operand;
+
+    emitLoad(src, regT1, regT0);
+    emitNotifyWrite(regT1, regT0, regT2, currentInstruction[3].u.watchpointSet);
+    emitStore(dst, regT1, regT0);
+}
+
 void JIT::emit_op_end(Instruction* currentInstruction)
 {
-    ASSERT(returnValueRegister != callFrameRegister);
+    ASSERT(returnValueGPR != callFrameRegister);
     emitLoad(currentInstruction[1].u.operand, regT1, regT0);
-    restoreReturnAddressBeforeReturn(Address(callFrameRegister, JSStack::ReturnPC * static_cast<int>(sizeof(Register))));
+    emitFunctionEpilogue();
     ret();
 }
 
@@ -214,7 +179,7 @@ void JIT::emit_op_jmp(Instruction* currentInstruction)
 void JIT::emit_op_new_object(Instruction* currentInstruction)
 {
     Structure* structure = currentInstruction[3].u.objectAllocationProfile->structure();
-    size_t allocationSize = JSObject::allocationSize(structure->inlineCapacity());
+    size_t allocationSize = JSFinalObject::allocationSize(structure->inlineCapacity());
     MarkedAllocator* allocator = &m_vm->heap.allocatorForObjectWithoutDestructor(allocationSize);
 
     RegisterID resultReg = regT0;
@@ -229,14 +194,15 @@ void JIT::emit_op_new_object(Instruction* currentInstruction)
 void JIT::emitSlow_op_new_object(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
 {
     linkSlowCase(iter);
-    JITStubCall stubCall(this, cti_op_new_object);
-    stubCall.addArgument(TrustedImmPtr(currentInstruction[3].u.objectAllocationProfile->structure()));
-    stubCall.call(currentInstruction[1].u.operand);
+    int dst = currentInstruction[1].u.operand;
+    Structure* structure = currentInstruction[3].u.objectAllocationProfile->structure();
+    callOperation(operationNewObject, structure);
+    emitStoreCell(dst, returnValueGPR);
 }
 
 void JIT::emit_op_check_has_instance(Instruction* currentInstruction)
 {
-    unsigned baseVal = currentInstruction[3].u.operand;
+    int baseVal = currentInstruction[3].u.operand;
 
     emitLoadPayload(baseVal, regT0);
 
@@ -244,15 +210,14 @@ void JIT::emit_op_check_has_instance(Instruction* currentInstruction)
     emitJumpSlowCaseIfNotJSCell(baseVal);
     
     // Check that baseVal 'ImplementsHasInstance'.
-    loadPtr(Address(regT0, JSCell::structureOffset()), regT0);
-    addSlowCase(branchTest8(Zero, Address(regT0, Structure::typeInfoFlagsOffset()), TrustedImm32(ImplementsDefaultHasInstance)));
+    addSlowCase(branchTest8(Zero, Address(regT0, JSCell::typeInfoFlagsOffset()), TrustedImm32(ImplementsDefaultHasInstance)));
 }
 
 void JIT::emit_op_instanceof(Instruction* currentInstruction)
 {
-    unsigned dst = currentInstruction[1].u.operand;
-    unsigned value = currentInstruction[2].u.operand;
-    unsigned proto = currentInstruction[3].u.operand;
+    int dst = currentInstruction[1].u.operand;
+    int value = currentInstruction[2].u.operand;
+    int proto = currentInstruction[3].u.operand;
 
     // Load the operands into registers.
     // We use regT0 for baseVal since we will be done with this first, and we can then use it for the result.
@@ -264,8 +229,7 @@ void JIT::emit_op_instanceof(Instruction* currentInstruction)
     emitJumpSlowCaseIfNotJSCell(proto);
     
     // Check that prototype is an object
-    loadPtr(Address(regT1, JSCell::structureOffset()), regT3);
-    addSlowCase(emitJumpIfNotObject(regT3));
+    addSlowCase(emitJumpIfCellNotObject(regT1));
 
     // Optimistically load the result true, and start looping.
     // Initially, regT1 still contains proto and regT2 still contains value.
@@ -275,7 +239,7 @@ void JIT::emit_op_instanceof(Instruction* currentInstruction)
 
     // Load the prototype of the cell in regT2.  If this is equal to regT1 - WIN!
     // Otherwise, check if we've hit null - if we have then drop out of the loop, if not go again.
-    loadPtr(Address(regT2, JSCell::structureOffset()), regT2);
+    loadPtr(Address(regT2, JSCell::structureIDOffset()), regT2);
     load32(Address(regT2, Structure::prototypeOffset() + OBJECT_OFFSETOF(JSValue, u.asBits.payload)), regT2);
     Jump isInstance = branchPtr(Equal, regT2, regT1);
     branchTest32(NonZero, regT2).linkTo(loop, this);
@@ -290,41 +254,39 @@ void JIT::emit_op_instanceof(Instruction* currentInstruction)
 
 void JIT::emitSlow_op_check_has_instance(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
 {
-    unsigned dst = currentInstruction[1].u.operand;
-    unsigned value = currentInstruction[2].u.operand;
-    unsigned baseVal = currentInstruction[3].u.operand;
+    int dst = currentInstruction[1].u.operand;
+    int value = currentInstruction[2].u.operand;
+    int baseVal = currentInstruction[3].u.operand;
 
     linkSlowCaseIfNotJSCell(iter, baseVal);
     linkSlowCase(iter);
 
-    JITStubCall stubCall(this, cti_op_check_has_instance);
-    stubCall.addArgument(value);
-    stubCall.addArgument(baseVal);
-    stubCall.call(dst);
+    emitLoad(value, regT1, regT0);
+    emitLoad(baseVal, regT3, regT2);
+    callOperation(operationCheckHasInstance, dst, regT1, regT0, regT3, regT2);
 
     emitJumpSlowToHot(jump(), currentInstruction[4].u.operand);
 }
 
 void JIT::emitSlow_op_instanceof(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
 {
-    unsigned dst = currentInstruction[1].u.operand;
-    unsigned value = currentInstruction[2].u.operand;
-    unsigned proto = currentInstruction[3].u.operand;
+    int dst = currentInstruction[1].u.operand;
+    int value = currentInstruction[2].u.operand;
+    int proto = currentInstruction[3].u.operand;
 
     linkSlowCaseIfNotJSCell(iter, value);
     linkSlowCaseIfNotJSCell(iter, proto);
     linkSlowCase(iter);
 
-    JITStubCall stubCall(this, cti_op_instanceof);
-    stubCall.addArgument(value);
-    stubCall.addArgument(proto);
-    stubCall.call(dst);
+    emitLoad(value, regT1, regT0);
+    emitLoad(proto, regT3, regT2);
+    callOperation(operationInstanceOf, dst, regT1, regT0, regT3, regT2);
 }
 
 void JIT::emit_op_is_undefined(Instruction* currentInstruction)
 {
-    unsigned dst = currentInstruction[1].u.operand;
-    unsigned value = currentInstruction[2].u.operand;
+    int dst = currentInstruction[1].u.operand;
+    int value = currentInstruction[2].u.operand;
     
     emitLoad(value, regT1, regT0);
     Jump isCell = branch32(Equal, regT1, TrustedImm32(JSValue::CellTag));
@@ -333,12 +295,12 @@ void JIT::emit_op_is_undefined(Instruction* currentInstruction)
     Jump done = jump();
     
     isCell.link(this);
-    loadPtr(Address(regT0, JSCell::structureOffset()), regT1);
-    Jump isMasqueradesAsUndefined = branchTest8(NonZero, Address(regT1, Structure::typeInfoFlagsOffset()), TrustedImm32(MasqueradesAsUndefined));
+    Jump isMasqueradesAsUndefined = branchTest8(NonZero, Address(regT0, JSCell::typeInfoFlagsOffset()), TrustedImm32(MasqueradesAsUndefined));
     move(TrustedImm32(0), regT0);
     Jump notMasqueradesAsUndefined = jump();
     
     isMasqueradesAsUndefined.link(this);
+    loadPtr(Address(regT0, JSCell::structureIDOffset()), regT1);
     move(TrustedImmPtr(m_codeBlock->globalObject()), regT0);
     loadPtr(Address(regT1, Structure::globalObjectOffset()), regT1);
     compare32(Equal, regT0, regT1, regT0);
@@ -350,8 +312,8 @@ void JIT::emit_op_is_undefined(Instruction* currentInstruction)
 
 void JIT::emit_op_is_boolean(Instruction* currentInstruction)
 {
-    unsigned dst = currentInstruction[1].u.operand;
-    unsigned value = currentInstruction[2].u.operand;
+    int dst = currentInstruction[1].u.operand;
+    int value = currentInstruction[2].u.operand;
     
     emitLoadTag(value, regT0);
     compare32(Equal, regT0, TrustedImm32(JSValue::BooleanTag), regT0);
@@ -360,8 +322,8 @@ void JIT::emit_op_is_boolean(Instruction* currentInstruction)
 
 void JIT::emit_op_is_number(Instruction* currentInstruction)
 {
-    unsigned dst = currentInstruction[1].u.operand;
-    unsigned value = currentInstruction[2].u.operand;
+    int dst = currentInstruction[1].u.operand;
+    int value = currentInstruction[2].u.operand;
     
     emitLoadTag(value, regT0);
     add32(TrustedImm32(1), regT0);
@@ -371,14 +333,13 @@ void JIT::emit_op_is_number(Instruction* currentInstruction)
 
 void JIT::emit_op_is_string(Instruction* currentInstruction)
 {
-    unsigned dst = currentInstruction[1].u.operand;
-    unsigned value = currentInstruction[2].u.operand;
+    int dst = currentInstruction[1].u.operand;
+    int value = currentInstruction[2].u.operand;
     
     emitLoad(value, regT1, regT0);
     Jump isNotCell = branch32(NotEqual, regT1, TrustedImm32(JSValue::CellTag));
     
-    loadPtr(Address(regT0, JSCell::structureOffset()), regT1);
-    compare8(Equal, Address(regT1, Structure::typeInfoTypeOffset()), TrustedImm32(StringType), regT0);
+    compare8(Equal, Address(regT0, JSCell::typeInfoTypeOffset()), TrustedImm32(StringType), regT0);
     Jump done = jump();
     
     isNotCell.link(this);
@@ -390,24 +351,22 @@ void JIT::emit_op_is_string(Instruction* currentInstruction)
 
 void JIT::emit_op_tear_off_activation(Instruction* currentInstruction)
 {
-    unsigned activation = currentInstruction[1].u.operand;
+    int activation = currentInstruction[1].u.operand;
     Jump activationNotCreated = branch32(Equal, tagFor(activation), TrustedImm32(JSValue::EmptyValueTag));
-    JITStubCall stubCall(this, cti_op_tear_off_activation);
-    stubCall.addArgument(activation);
-    stubCall.call();
+    emitLoadPayload(activation, regT0);
+    callOperation(operationTearOffActivation, regT0);
     activationNotCreated.link(this);
 }
 
 void JIT::emit_op_tear_off_arguments(Instruction* currentInstruction)
 {
-    int arguments = currentInstruction[1].u.operand;
+    VirtualRegister arguments = VirtualRegister(currentInstruction[1].u.operand);
     int activation = currentInstruction[2].u.operand;
 
-    Jump argsNotCreated = branch32(Equal, tagFor(unmodifiedArgumentsRegister(arguments)), TrustedImm32(JSValue::EmptyValueTag));
-    JITStubCall stubCall(this, cti_op_tear_off_arguments);
-    stubCall.addArgument(unmodifiedArgumentsRegister(arguments));
-    stubCall.addArgument(activation);
-    stubCall.call();
+    Jump argsNotCreated = branch32(Equal, tagFor(unmodifiedArgumentsRegister(arguments).offset()), TrustedImm32(JSValue::EmptyValueTag));
+    emitLoadPayload(unmodifiedArgumentsRegister(VirtualRegister(arguments)).offset(), regT0);
+    emitLoadPayload(activation, regT1);
+    callOperation(operationTearOffArguments, regT0, regT1);
     argsNotCreated.link(this);
 }
 
@@ -419,37 +378,31 @@ void JIT::emit_op_to_primitive(Instruction* currentInstruction)
     emitLoad(src, regT1, regT0);
 
     Jump isImm = branch32(NotEqual, regT1, TrustedImm32(JSValue::CellTag));
-    addSlowCase(branchPtr(NotEqual, Address(regT0, JSCell::structureOffset()), TrustedImmPtr(m_vm->stringStructure.get())));
+    addSlowCase(branchPtr(NotEqual, Address(regT0, JSCell::structureIDOffset()), TrustedImmPtr(m_vm->stringStructure.get())));
     isImm.link(this);
 
     if (dst != src)
         emitStore(dst, regT1, regT0);
-    map(m_bytecodeOffset + OPCODE_LENGTH(op_to_primitive), dst, regT1, regT0);
 }
 
 void JIT::emitSlow_op_to_primitive(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
 {
-    int dst = currentInstruction[1].u.operand;
-
     linkSlowCase(iter);
 
-    JITStubCall stubCall(this, cti_op_to_primitive);
-    stubCall.addArgument(regT1, regT0);
-    stubCall.call(dst);
+    JITSlowPathCall slowPathCall(this, currentInstruction, slow_path_to_primitive);
+    slowPathCall.call();
 }
 
 void JIT::emit_op_strcat(Instruction* currentInstruction)
 {
-    JITStubCall stubCall(this, cti_op_strcat);
-    stubCall.addArgument(TrustedImm32(currentInstruction[2].u.operand));
-    stubCall.addArgument(TrustedImm32(currentInstruction[3].u.operand));
-    stubCall.call(currentInstruction[1].u.operand);
+    JITSlowPathCall slowPathCall(this, currentInstruction, slow_path_strcat);
+    slowPathCall.call();
 }
 
 void JIT::emit_op_not(Instruction* currentInstruction)
 {
-    unsigned dst = currentInstruction[1].u.operand;
-    unsigned src = currentInstruction[2].u.operand;
+    int dst = currentInstruction[1].u.operand;
+    int src = currentInstruction[2].u.operand;
 
     emitLoadTag(src, regT0);
 
@@ -462,19 +415,15 @@ void JIT::emit_op_not(Instruction* currentInstruction)
 
 void JIT::emitSlow_op_not(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
 {
-    unsigned dst = currentInstruction[1].u.operand;
-    unsigned src = currentInstruction[2].u.operand;
-
     linkSlowCase(iter);
 
-    JITStubCall stubCall(this, cti_op_not);
-    stubCall.addArgument(src);
-    stubCall.call(dst);
+    JITSlowPathCall slowPathCall(this, currentInstruction, slow_path_not);
+    slowPathCall.call();
 }
 
 void JIT::emit_op_jfalse(Instruction* currentInstruction)
 {
-    unsigned cond = currentInstruction[1].u.operand;
+    int cond = currentInstruction[1].u.operand;
     unsigned target = currentInstruction[2].u.operand;
 
     emitLoad(cond, regT1, regT0);
@@ -486,7 +435,7 @@ void JIT::emit_op_jfalse(Instruction* currentInstruction)
 
 void JIT::emitSlow_op_jfalse(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
 {
-    unsigned cond = currentInstruction[1].u.operand;
+    int cond = currentInstruction[1].u.operand;
     unsigned target = currentInstruction[2].u.operand;
 
     linkSlowCase(iter);
@@ -502,15 +451,13 @@ void JIT::emitSlow_op_jfalse(Instruction* currentInstruction, Vector<SlowCaseEnt
         notNumber.link(this);
     }
 
-    JITStubCall stubCall(this, cti_op_jtrue);
-    stubCall.addArgument(cond);
-    stubCall.call();
-    emitJumpSlowToHot(branchTest32(Zero, regT0), target); // Inverted.
+    callOperation(operationConvertJSValueToBoolean, regT1, regT0);
+    emitJumpSlowToHot(branchTest32(Zero, returnValueGPR), target); // Inverted.
 }
 
 void JIT::emit_op_jtrue(Instruction* currentInstruction)
 {
-    unsigned cond = currentInstruction[1].u.operand;
+    int cond = currentInstruction[1].u.operand;
     unsigned target = currentInstruction[2].u.operand;
 
     emitLoad(cond, regT1, regT0);
@@ -522,7 +469,7 @@ void JIT::emit_op_jtrue(Instruction* currentInstruction)
 
 void JIT::emitSlow_op_jtrue(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
 {
-    unsigned cond = currentInstruction[1].u.operand;
+    int cond = currentInstruction[1].u.operand;
     unsigned target = currentInstruction[2].u.operand;
 
     linkSlowCase(iter);
@@ -538,24 +485,21 @@ void JIT::emitSlow_op_jtrue(Instruction* currentInstruction, Vector<SlowCaseEntr
         notNumber.link(this);
     }
 
-    JITStubCall stubCall(this, cti_op_jtrue);
-    stubCall.addArgument(cond);
-    stubCall.call();
-    emitJumpSlowToHot(branchTest32(NonZero, regT0), target);
+    callOperation(operationConvertJSValueToBoolean, regT1, regT0);
+    emitJumpSlowToHot(branchTest32(NonZero, returnValueGPR), target);
 }
 
 void JIT::emit_op_jeq_null(Instruction* currentInstruction)
 {
-    unsigned src = currentInstruction[1].u.operand;
+    int src = currentInstruction[1].u.operand;
     unsigned target = currentInstruction[2].u.operand;
 
     emitLoad(src, regT1, regT0);
 
     Jump isImmediate = branch32(NotEqual, regT1, TrustedImm32(JSValue::CellTag));
 
-    // First, handle JSCell cases - check MasqueradesAsUndefined bit on the structure.
-    loadPtr(Address(regT0, JSCell::structureOffset()), regT2);
-    Jump isNotMasqueradesAsUndefined = branchTest8(Zero, Address(regT2, Structure::typeInfoFlagsOffset()), TrustedImm32(MasqueradesAsUndefined));
+    Jump isNotMasqueradesAsUndefined = branchTest8(Zero, Address(regT0, JSCell::typeInfoFlagsOffset()), TrustedImm32(MasqueradesAsUndefined));
+    loadPtr(Address(regT0, JSCell::structureIDOffset()), regT2);
     move(TrustedImmPtr(m_codeBlock->globalObject()), regT0);
     addJump(branchPtr(Equal, Address(regT2, Structure::globalObjectOffset()), regT0), target);
     Jump masqueradesGlobalObjectIsForeign = jump();
@@ -572,16 +516,15 @@ void JIT::emit_op_jeq_null(Instruction* currentInstruction)
 
 void JIT::emit_op_jneq_null(Instruction* currentInstruction)
 {
-    unsigned src = currentInstruction[1].u.operand;
+    int src = currentInstruction[1].u.operand;
     unsigned target = currentInstruction[2].u.operand;
 
     emitLoad(src, regT1, regT0);
 
     Jump isImmediate = branch32(NotEqual, regT1, TrustedImm32(JSValue::CellTag));
 
-    // First, handle JSCell cases - check MasqueradesAsUndefined bit on the structure.
-    loadPtr(Address(regT0, JSCell::structureOffset()), regT2);
-    addJump(branchTest8(Zero, Address(regT2, Structure::typeInfoFlagsOffset()), TrustedImm32(MasqueradesAsUndefined)), target);
+    addJump(branchTest8(Zero, Address(regT0, JSCell::typeInfoFlagsOffset()), TrustedImm32(MasqueradesAsUndefined)), target);
+    loadPtr(Address(regT0, JSCell::structureIDOffset()), regT2);
     move(TrustedImmPtr(m_codeBlock->globalObject()), regT0);
     addJump(branchPtr(NotEqual, Address(regT2, Structure::globalObjectOffset()), regT0), target);
     Jump wasNotImmediate = jump();
@@ -598,7 +541,7 @@ void JIT::emit_op_jneq_null(Instruction* currentInstruction)
 
 void JIT::emit_op_jneq_ptr(Instruction* currentInstruction)
 {
-    unsigned src = currentInstruction[1].u.operand;
+    int src = currentInstruction[1].u.operand;
     Special::Pointer ptr = currentInstruction[2].u.specialPointer;
     unsigned target = currentInstruction[3].u.operand;
 
@@ -609,9 +552,9 @@ void JIT::emit_op_jneq_ptr(Instruction* currentInstruction)
 
 void JIT::emit_op_eq(Instruction* currentInstruction)
 {
-    unsigned dst = currentInstruction[1].u.operand;
-    unsigned src1 = currentInstruction[2].u.operand;
-    unsigned src2 = currentInstruction[3].u.operand;
+    int dst = currentInstruction[1].u.operand;
+    int src1 = currentInstruction[2].u.operand;
+    int src2 = currentInstruction[3].u.operand;
 
     emitLoad2(src1, regT1, regT0, src2, regT3, regT2);
     addSlowCase(branch32(NotEqual, regT1, regT3));
@@ -625,9 +568,9 @@ void JIT::emit_op_eq(Instruction* currentInstruction)
 
 void JIT::emitSlow_op_eq(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
 {
-    unsigned dst = currentInstruction[1].u.operand;
-    unsigned op1 = currentInstruction[2].u.operand;
-    unsigned op2 = currentInstruction[3].u.operand;
+    int dst = currentInstruction[1].u.operand;
+    int op1 = currentInstruction[2].u.operand;
+    int op2 = currentInstruction[3].u.operand;
 
     JumpList storeResult;
     JumpList genericCase;
@@ -635,33 +578,29 @@ void JIT::emitSlow_op_eq(Instruction* currentInstruction, Vector<SlowCaseEntry>:
     genericCase.append(getSlowCase(iter)); // tags not equal
 
     linkSlowCase(iter); // tags equal and JSCell
-    genericCase.append(branchPtr(NotEqual, Address(regT0, JSCell::structureOffset()), TrustedImmPtr(m_vm->stringStructure.get())));
-    genericCase.append(branchPtr(NotEqual, Address(regT2, JSCell::structureOffset()), TrustedImmPtr(m_vm->stringStructure.get())));
+    genericCase.append(branchPtr(NotEqual, Address(regT0, JSCell::structureIDOffset()), TrustedImmPtr(m_vm->stringStructure.get())));
+    genericCase.append(branchPtr(NotEqual, Address(regT2, JSCell::structureIDOffset()), TrustedImmPtr(m_vm->stringStructure.get())));
 
     // String case.
-    JITStubCall stubCallEqStrings(this, cti_op_eq_strings);
-    stubCallEqStrings.addArgument(regT0);
-    stubCallEqStrings.addArgument(regT2);
-    stubCallEqStrings.call();
+    callOperation(operationCompareStringEq, regT0, regT2);
     storeResult.append(jump());
 
     // Generic case.
     genericCase.append(getSlowCase(iter)); // doubles
     genericCase.link(this);
-    JITStubCall stubCallEq(this, cti_op_eq);
-    stubCallEq.addArgument(op1);
-    stubCallEq.addArgument(op2);
-    stubCallEq.call(regT0);
+    emitLoad(op1, regT1, regT0);
+    emitLoad(op2, regT3, regT2);
+    callOperation(operationCompareEq, regT1, regT0, regT3, regT2);
 
     storeResult.link(this);
-    emitStoreBool(dst, regT0);
+    emitStoreBool(dst, returnValueGPR);
 }
 
 void JIT::emit_op_neq(Instruction* currentInstruction)
 {
-    unsigned dst = currentInstruction[1].u.operand;
-    unsigned src1 = currentInstruction[2].u.operand;
-    unsigned src2 = currentInstruction[3].u.operand;
+    int dst = currentInstruction[1].u.operand;
+    int src1 = currentInstruction[2].u.operand;
+    int src2 = currentInstruction[3].u.operand;
 
     emitLoad2(src1, regT1, regT0, src2, regT3, regT2);
     addSlowCase(branch32(NotEqual, regT1, regT3));
@@ -675,7 +614,7 @@ void JIT::emit_op_neq(Instruction* currentInstruction)
 
 void JIT::emitSlow_op_neq(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
 {
-    unsigned dst = currentInstruction[1].u.operand;
+    int dst = currentInstruction[1].u.operand;
 
     JumpList storeResult;
     JumpList genericCase;
@@ -683,34 +622,28 @@ void JIT::emitSlow_op_neq(Instruction* currentInstruction, Vector<SlowCaseEntry>
     genericCase.append(getSlowCase(iter)); // tags not equal
 
     linkSlowCase(iter); // tags equal and JSCell
-    genericCase.append(branchPtr(NotEqual, Address(regT0, JSCell::structureOffset()), TrustedImmPtr(m_vm->stringStructure.get())));
-    genericCase.append(branchPtr(NotEqual, Address(regT2, JSCell::structureOffset()), TrustedImmPtr(m_vm->stringStructure.get())));
+    genericCase.append(branchPtr(NotEqual, Address(regT0, JSCell::structureIDOffset()), TrustedImmPtr(m_vm->stringStructure.get())));
+    genericCase.append(branchPtr(NotEqual, Address(regT2, JSCell::structureIDOffset()), TrustedImmPtr(m_vm->stringStructure.get())));
 
     // String case.
-    JITStubCall stubCallEqStrings(this, cti_op_eq_strings);
-    stubCallEqStrings.addArgument(regT0);
-    stubCallEqStrings.addArgument(regT2);
-    stubCallEqStrings.call(regT0);
+    callOperation(operationCompareStringEq, regT0, regT2);
     storeResult.append(jump());
 
     // Generic case.
     genericCase.append(getSlowCase(iter)); // doubles
     genericCase.link(this);
-    JITStubCall stubCallEq(this, cti_op_eq);
-    stubCallEq.addArgument(regT1, regT0);
-    stubCallEq.addArgument(regT3, regT2);
-    stubCallEq.call(regT0);
+    callOperation(operationCompareEq, regT1, regT0, regT3, regT2);
 
     storeResult.link(this);
-    xor32(TrustedImm32(0x1), regT0);
-    emitStoreBool(dst, regT0);
+    xor32(TrustedImm32(0x1), returnValueGPR);
+    emitStoreBool(dst, returnValueGPR);
 }
 
 void JIT::compileOpStrictEq(Instruction* currentInstruction, CompileOpStrictEqType type)
 {
-    unsigned dst = currentInstruction[1].u.operand;
-    unsigned src1 = currentInstruction[2].u.operand;
-    unsigned src2 = currentInstruction[3].u.operand;
+    int dst = currentInstruction[1].u.operand;
+    int src1 = currentInstruction[2].u.operand;
+    int src2 = currentInstruction[3].u.operand;
 
     emitLoad2(src1, regT1, regT0, src2, regT3, regT2);
 
@@ -720,8 +653,8 @@ void JIT::compileOpStrictEq(Instruction* currentInstruction, CompileOpStrictEqTy
 
     // Jump to a slow case if both are strings.
     Jump notCell = branch32(NotEqual, regT1, TrustedImm32(JSValue::CellTag));
-    Jump firstNotString = branchPtr(NotEqual, Address(regT0, JSCell::structureOffset()), TrustedImmPtr(m_vm->stringStructure.get()));
-    addSlowCase(branchPtr(Equal, Address(regT2, JSCell::structureOffset()), TrustedImmPtr(m_vm->stringStructure.get())));
+    Jump firstNotString = branchPtr(NotEqual, Address(regT0, JSCell::structureIDOffset()), TrustedImmPtr(m_vm->stringStructure.get()));
+    addSlowCase(branchPtr(Equal, Address(regT2, JSCell::structureIDOffset()), TrustedImmPtr(m_vm->stringStructure.get())));
     notCell.link(this);
     firstNotString.link(this);
 
@@ -741,18 +674,12 @@ void JIT::emit_op_stricteq(Instruction* currentInstruction)
 
 void JIT::emitSlow_op_stricteq(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
 {
-    unsigned dst = currentInstruction[1].u.operand;
-    unsigned src1 = currentInstruction[2].u.operand;
-    unsigned src2 = currentInstruction[3].u.operand;
-
     linkSlowCase(iter);
     linkSlowCase(iter);
     linkSlowCase(iter);
 
-    JITStubCall stubCall(this, cti_op_stricteq);
-    stubCall.addArgument(src1);
-    stubCall.addArgument(src2);
-    stubCall.call(dst);
+    JITSlowPathCall slowPathCall(this, currentInstruction, slow_path_stricteq);
+    slowPathCall.call();
 }
 
 void JIT::emit_op_nstricteq(Instruction* currentInstruction)
@@ -762,34 +689,28 @@ void JIT::emit_op_nstricteq(Instruction* currentInstruction)
 
 void JIT::emitSlow_op_nstricteq(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
 {
-    unsigned dst = currentInstruction[1].u.operand;
-    unsigned src1 = currentInstruction[2].u.operand;
-    unsigned src2 = currentInstruction[3].u.operand;
-
     linkSlowCase(iter);
     linkSlowCase(iter);
     linkSlowCase(iter);
 
-    JITStubCall stubCall(this, cti_op_nstricteq);
-    stubCall.addArgument(src1);
-    stubCall.addArgument(src2);
-    stubCall.call(dst);
+    JITSlowPathCall slowPathCall(this, currentInstruction, slow_path_nstricteq);
+    slowPathCall.call();
 }
 
 void JIT::emit_op_eq_null(Instruction* currentInstruction)
 {
-    unsigned dst = currentInstruction[1].u.operand;
-    unsigned src = currentInstruction[2].u.operand;
+    int dst = currentInstruction[1].u.operand;
+    int src = currentInstruction[2].u.operand;
 
     emitLoad(src, regT1, regT0);
     Jump isImmediate = branch32(NotEqual, regT1, TrustedImm32(JSValue::CellTag));
 
-    loadPtr(Address(regT0, JSCell::structureOffset()), regT2);
-    Jump isMasqueradesAsUndefined = branchTest8(NonZero, Address(regT2, Structure::typeInfoFlagsOffset()), TrustedImm32(MasqueradesAsUndefined));
+    Jump isMasqueradesAsUndefined = branchTest8(NonZero, Address(regT0, JSCell::typeInfoFlagsOffset()), TrustedImm32(MasqueradesAsUndefined));
     move(TrustedImm32(0), regT1);
     Jump wasNotMasqueradesAsUndefined = jump();
 
     isMasqueradesAsUndefined.link(this);
+    loadPtr(Address(regT0, JSCell::structureIDOffset()), regT2);
     move(TrustedImmPtr(m_codeBlock->globalObject()), regT0);
     loadPtr(Address(regT2, Structure::globalObjectOffset()), regT2);
     compare32(Equal, regT0, regT2, regT1);
@@ -809,18 +730,18 @@ void JIT::emit_op_eq_null(Instruction* currentInstruction)
 
 void JIT::emit_op_neq_null(Instruction* currentInstruction)
 {
-    unsigned dst = currentInstruction[1].u.operand;
-    unsigned src = currentInstruction[2].u.operand;
+    int dst = currentInstruction[1].u.operand;
+    int src = currentInstruction[2].u.operand;
 
     emitLoad(src, regT1, regT0);
     Jump isImmediate = branch32(NotEqual, regT1, TrustedImm32(JSValue::CellTag));
 
-    loadPtr(Address(regT0, JSCell::structureOffset()), regT2);
-    Jump isMasqueradesAsUndefined = branchTest8(NonZero, Address(regT2, Structure::typeInfoFlagsOffset()), TrustedImm32(MasqueradesAsUndefined));
+    Jump isMasqueradesAsUndefined = branchTest8(NonZero, Address(regT0, JSCell::typeInfoFlagsOffset()), TrustedImm32(MasqueradesAsUndefined));
     move(TrustedImm32(1), regT1);
     Jump wasNotMasqueradesAsUndefined = jump();
 
     isMasqueradesAsUndefined.link(this);
+    loadPtr(Address(regT0, JSCell::structureIDOffset()), regT2);
     move(TrustedImmPtr(m_codeBlock->globalObject()), regT0);
     loadPtr(Address(regT2, Structure::globalObjectOffset()), regT2);
     compare32(NotEqual, regT0, regT2, regT1);
@@ -840,16 +761,10 @@ void JIT::emit_op_neq_null(Instruction* currentInstruction)
 
 void JIT::emit_op_throw(Instruction* currentInstruction)
 {
-    unsigned exception = currentInstruction[1].u.operand;
-    JITStubCall stubCall(this, cti_op_throw);
-    stubCall.addArgument(exception);
-    stubCall.call();
-
-#ifndef NDEBUG
-    // cti_op_throw always changes it's return address,
-    // this point in the code should never be reached.
-    breakpoint();
-#endif
+    ASSERT(regT0 == returnValueGPR);
+    emitLoad(currentInstruction[1].u.operand, regT1, regT0);
+    callOperationNoExceptionCheck(operationThrow, regT1, regT0);
+    jumpToExceptionHandler();
 }
 
 void JIT::emit_op_get_pnames(Instruction* currentInstruction)
@@ -865,17 +780,14 @@ void JIT::emit_op_get_pnames(Instruction* currentInstruction)
     emitLoad(base, regT1, regT0);
     if (!m_codeBlock->isKnownNotImmediate(base))
         isNotObject.append(branch32(NotEqual, regT1, TrustedImm32(JSValue::CellTag)));
-    if (base != m_codeBlock->thisRegister() || m_codeBlock->isStrictMode()) {
-        loadPtr(Address(regT0, JSCell::structureOffset()), regT2);
-        isNotObject.append(emitJumpIfNotObject(regT2));
-    }
+    if (VirtualRegister(base) != m_codeBlock->thisRegister() || m_codeBlock->isStrictMode())
+        isNotObject.append(emitJumpIfCellNotObject(regT0));
 
     // We could inline the case where you have a valid cache, but
     // this call doesn't seem to be hot.
     Label isObject(this);
-    JITStubCall getPnamesStubCall(this, cti_op_get_pnames);
-    getPnamesStubCall.addArgument(regT0);
-    getPnamesStubCall.call(dst);
+    callOperation(operationGetPNames, regT0);
+    emitStoreCell(dst, returnValueGPR);
     load32(Address(regT0, OBJECT_OFFSETOF(JSPropertyNameIterator, m_jsStringsSize)), regT3);
     store32(TrustedImm32(Int32Tag), intTagFor(i));
     store32(TrustedImm32(0), intPayloadFor(i));
@@ -886,9 +798,7 @@ void JIT::emit_op_get_pnames(Instruction* currentInstruction)
     isNotObject.link(this);
     addJump(branch32(Equal, regT1, TrustedImm32(JSValue::NullTag)), breakTarget);
     addJump(branch32(Equal, regT1, TrustedImm32(JSValue::UndefinedTag)), breakTarget);
-    JITStubCall toObjectStubCall(this, cti_to_object);
-    toObjectStubCall.addArgument(regT1, regT0);
-    toObjectStubCall.call(base);
+    callOperation(operationToObject, base, regT1, regT0);
     jump().linkTo(isObject, this);
 
     end.link(this);
@@ -924,7 +834,7 @@ void JIT::emit_op_next_pname(Instruction* currentInstruction)
     loadPtr(payloadFor(base), regT0);
 
     // Test base's structure
-    loadPtr(Address(regT0, JSCell::structureOffset()), regT2);
+    loadPtr(Address(regT0, JSCell::structureIDOffset()), regT2);
     callHasProperty.append(branchPtr(NotEqual, regT2, Address(Address(regT1, OBJECT_OFFSETOF(JSPropertyNameIterator, m_cachedStructure)))));
 
     // Test base's prototype chain
@@ -935,7 +845,7 @@ void JIT::emit_op_next_pname(Instruction* currentInstruction)
     Label checkPrototype(this);
     callHasProperty.append(branch32(Equal, Address(regT2, Structure::prototypeOffset() + OBJECT_OFFSETOF(JSValue, u.asBits.tag)), TrustedImm32(JSValue::NullTag)));
     loadPtr(Address(regT2, Structure::prototypeOffset() + OBJECT_OFFSETOF(JSValue, u.asBits.payload)), regT2);
-    loadPtr(Address(regT2, JSCell::structureOffset()), regT2);
+    loadPtr(Address(regT2, JSCell::structureIDOffset()), regT2);
     callHasProperty.append(branchPtr(NotEqual, regT2, Address(regT3)));
     addPtr(TrustedImm32(sizeof(Structure*)), regT3);
     branchTestPtr(NonZero, Address(regT3)).linkTo(checkPrototype, this);
@@ -946,10 +856,7 @@ void JIT::emit_op_next_pname(Instruction* currentInstruction)
     // Slow case: Ask the object if i is valid.
     callHasProperty.link(this);
     loadPtr(addressFor(dst), regT1);
-    JITStubCall stubCall(this, cti_has_property);
-    stubCall.addArgument(regT0);
-    stubCall.addArgument(regT1);
-    stubCall.call();
+    callOperation(operationHasProperty, regT0, regT1);
 
     // Test for valid key.
     addJump(branchTest32(NonZero, regT0), target);
@@ -961,14 +868,13 @@ void JIT::emit_op_next_pname(Instruction* currentInstruction)
 
 void JIT::emit_op_push_with_scope(Instruction* currentInstruction)
 {
-    JITStubCall stubCall(this, cti_op_push_with_scope);
-    stubCall.addArgument(currentInstruction[1].u.operand);
-    stubCall.call();
+    emitLoad(currentInstruction[1].u.operand, regT1, regT0);
+    callOperation(operationPushWithScope, regT1, regT0);
 }
 
 void JIT::emit_op_pop_scope(Instruction*)
 {
-    JITStubCall(this, cti_op_pop_scope).call();
+    callOperation(operationPopScope);
 }
 
 void JIT::emit_op_to_number(Instruction* currentInstruction)
@@ -984,85 +890,75 @@ void JIT::emit_op_to_number(Instruction* currentInstruction)
 
     if (src != dst)
         emitStore(dst, regT1, regT0);
-    map(m_bytecodeOffset + OPCODE_LENGTH(op_to_number), dst, regT1, regT0);
 }
 
 void JIT::emitSlow_op_to_number(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
 {
-    int dst = currentInstruction[1].u.operand;
-
     linkSlowCase(iter);
 
-    JITStubCall stubCall(this, cti_op_to_number);
-    stubCall.addArgument(regT1, regT0);
-    stubCall.call(dst);
+    JITSlowPathCall slowPathCall(this, currentInstruction, slow_path_to_number);
+    slowPathCall.call();
 }
 
 void JIT::emit_op_push_name_scope(Instruction* currentInstruction)
 {
-    JITStubCall stubCall(this, cti_op_push_name_scope);
-    stubCall.addArgument(TrustedImmPtr(&m_codeBlock->identifier(currentInstruction[1].u.operand)));
-    stubCall.addArgument(currentInstruction[2].u.operand);
-    stubCall.addArgument(TrustedImm32(currentInstruction[3].u.operand));
-    stubCall.call();
+    emitLoad(currentInstruction[2].u.operand, regT1, regT0);
+    callOperation(operationPushNameScope, &m_codeBlock->identifier(currentInstruction[1].u.operand), regT1, regT0, currentInstruction[3].u.operand);
 }
 
 void JIT::emit_op_catch(Instruction* currentInstruction)
 {
-    // cti_op_throw returns the callFrame for the handler.
-    move(regT0, callFrameRegister);
+    move(TrustedImmPtr(m_vm), regT3);
+    // operationThrow returns the callFrame for the handler.
+    load32(Address(regT3, VM::callFrameForThrowOffset()), callFrameRegister);
+
+    addPtr(TrustedImm32(stackPointerOffsetFor(codeBlock()) * sizeof(Register)), callFrameRegister, stackPointerRegister);
 
-    // Now store the exception returned by cti_op_throw.
-    loadPtr(Address(stackPointerRegister, OBJECT_OFFSETOF(struct JITStackFrame, vm)), regT3);
-    load32(Address(regT3, OBJECT_OFFSETOF(VM, exception) + OBJECT_OFFSETOF(JSValue, u.asBits.payload)), regT0);
-    load32(Address(regT3, OBJECT_OFFSETOF(VM, exception) + OBJECT_OFFSETOF(JSValue, u.asBits.tag)), regT1);
-    store32(TrustedImm32(JSValue().payload()), Address(regT3, OBJECT_OFFSETOF(VM, exception) + OBJECT_OFFSETOF(JSValue, u.asBits.payload)));
-    store32(TrustedImm32(JSValue().tag()), Address(regT3, OBJECT_OFFSETOF(VM, exception) + OBJECT_OFFSETOF(JSValue, u.asBits.tag)));
+    // Now store the exception returned by operationThrow.
+    load32(Address(regT3, VM::exceptionOffset() + OBJECT_OFFSETOF(JSValue, u.asBits.payload)), regT0);
+    load32(Address(regT3, VM::exceptionOffset() + OBJECT_OFFSETOF(JSValue, u.asBits.tag)), regT1);
+    store32(TrustedImm32(JSValue().payload()), Address(regT3, VM::exceptionOffset() + OBJECT_OFFSETOF(JSValue, u.asBits.payload)));
+    store32(TrustedImm32(JSValue().tag()), Address(regT3, VM::exceptionOffset() + OBJECT_OFFSETOF(JSValue, u.asBits.tag)));
 
     unsigned exception = currentInstruction[1].u.operand;
     emitStore(exception, regT1, regT0);
-    map(m_bytecodeOffset + OPCODE_LENGTH(op_catch), exception, regT1, regT0);
 }
 
 void JIT::emit_op_switch_imm(Instruction* currentInstruction)
 {
-    unsigned tableIndex = currentInstruction[1].u.operand;
+    size_t tableIndex = currentInstruction[1].u.operand;
     unsigned defaultOffset = currentInstruction[2].u.operand;
     unsigned scrutinee = currentInstruction[3].u.operand;
 
     // create jump table for switch destinations, track this switch statement.
-    SimpleJumpTable* jumpTable = &m_codeBlock->immediateSwitchJumpTable(tableIndex);
+    SimpleJumpTable* jumpTable = &m_codeBlock->switchJumpTable(tableIndex);
     m_switches.append(SwitchRecord(jumpTable, m_bytecodeOffset, defaultOffset, SwitchRecord::Immediate));
-    jumpTable->ctiOffsets.grow(jumpTable->branchOffsets.size());
+    jumpTable->ensureCTITable();
 
-    JITStubCall stubCall(this, cti_op_switch_imm);
-    stubCall.addArgument(scrutinee);
-    stubCall.addArgument(TrustedImm32(tableIndex));
-    stubCall.call();
-    jump(regT0);
+    emitLoad(scrutinee, regT1, regT0);
+    callOperation(operationSwitchImmWithUnknownKeyType, regT1, regT0, tableIndex);
+    jump(returnValueGPR);
 }
 
 void JIT::emit_op_switch_char(Instruction* currentInstruction)
 {
-    unsigned tableIndex = currentInstruction[1].u.operand;
+    size_t tableIndex = currentInstruction[1].u.operand;
     unsigned defaultOffset = currentInstruction[2].u.operand;
     unsigned scrutinee = currentInstruction[3].u.operand;
 
     // create jump table for switch destinations, track this switch statement.
-    SimpleJumpTable* jumpTable = &m_codeBlock->characterSwitchJumpTable(tableIndex);
+    SimpleJumpTable* jumpTable = &m_codeBlock->switchJumpTable(tableIndex);
     m_switches.append(SwitchRecord(jumpTable, m_bytecodeOffset, defaultOffset, SwitchRecord::Character));
-    jumpTable->ctiOffsets.grow(jumpTable->branchOffsets.size());
+    jumpTable->ensureCTITable();
 
-    JITStubCall stubCall(this, cti_op_switch_char);
-    stubCall.addArgument(scrutinee);
-    stubCall.addArgument(TrustedImm32(tableIndex));
-    stubCall.call();
-    jump(regT0);
+    emitLoad(scrutinee, regT1, regT0);
+    callOperation(operationSwitchCharWithUnknownKeyType, regT1, regT0, tableIndex);
+    jump(returnValueGPR);
 }
 
 void JIT::emit_op_switch_string(Instruction* currentInstruction)
 {
-    unsigned tableIndex = currentInstruction[1].u.operand;
+    size_t tableIndex = currentInstruction[1].u.operand;
     unsigned defaultOffset = currentInstruction[2].u.operand;
     unsigned scrutinee = currentInstruction[3].u.operand;
 
@@ -1070,40 +966,27 @@ void JIT::emit_op_switch_string(Instruction* currentInstruction)
     StringJumpTable* jumpTable = &m_codeBlock->stringSwitchJumpTable(tableIndex);
     m_switches.append(SwitchRecord(jumpTable, m_bytecodeOffset, defaultOffset));
 
-    JITStubCall stubCall(this, cti_op_switch_string);
-    stubCall.addArgument(scrutinee);
-    stubCall.addArgument(TrustedImm32(tableIndex));
-    stubCall.call();
-    jump(regT0);
+    emitLoad(scrutinee, regT1, regT0);
+    callOperation(operationSwitchStringWithUnknownKeyType, regT1, regT0, tableIndex);
+    jump(returnValueGPR);
 }
 
 void JIT::emit_op_throw_static_error(Instruction* currentInstruction)
 {
-    unsigned message = currentInstruction[1].u.operand;
-
-    JITStubCall stubCall(this, cti_op_throw_static_error);
-    stubCall.addArgument(m_codeBlock->getConstant(message));
-    stubCall.addArgument(TrustedImm32(currentInstruction[2].u.operand));
-    stubCall.call();
+    emitLoad(m_codeBlock->getConstant(currentInstruction[1].u.operand), regT1, regT0);
+    callOperation(operationThrowStaticError, regT1, regT0, currentInstruction[2].u.operand);
 }
 
 void JIT::emit_op_debug(Instruction* currentInstruction)
 {
-#if ENABLE(DEBUG_WITH_BREAKPOINT)
-    UNUSED_PARAM(currentInstruction);
-    breakpoint();
-#else
-    JITStubCall stubCall(this, cti_op_debug);
-    stubCall.addArgument(Imm32(currentInstruction[1].u.operand));
-    stubCall.addArgument(Imm32(currentInstruction[2].u.operand));
-    stubCall.addArgument(Imm32(currentInstruction[3].u.operand));
-    stubCall.addArgument(Imm32(currentInstruction[4].u.operand));
-    stubCall.call();
-#endif
+    load32(codeBlock()->debuggerRequestsAddress(), regT0);
+    Jump noDebuggerRequests = branchTest32(Zero, regT0);
+    callOperation(operationDebug, currentInstruction[1].u.operand);
+    noDebuggerRequests.link(this);
 }
 
 
-void JIT::emit_op_enter(Instruction*)
+void JIT::emit_op_enter(Instruction* currentInstruction)
 {
     emitEnterOptimizationCheck();
     
@@ -1111,45 +994,59 @@ void JIT::emit_op_enter(Instruction*)
     // registers to zap stale pointers, to avoid unnecessarily prolonging
     // object lifetime and increasing GC pressure.
     for (int i = 0; i < m_codeBlock->m_numVars; ++i)
-        emitStore(i, jsUndefined());
+        emitStore(virtualRegisterForLocal(i).offset(), jsUndefined());
+
+    JITSlowPathCall slowPathCall(this, currentInstruction, slow_path_enter);
+    slowPathCall.call();
 }
 
 void JIT::emit_op_create_activation(Instruction* currentInstruction)
 {
-    unsigned activation = currentInstruction[1].u.operand;
+    int activation = currentInstruction[1].u.operand;
     
     Jump activationCreated = branch32(NotEqual, tagFor(activation), TrustedImm32(JSValue::EmptyValueTag));
-    JITStubCall(this, cti_op_push_activation).call(activation);
+    callOperation(operationCreateActivation, 0);
+    emitStoreCell(activation, returnValueGPR);
     activationCreated.link(this);
 }
 
 void JIT::emit_op_create_arguments(Instruction* currentInstruction)
 {
-    unsigned dst = currentInstruction[1].u.operand;
+    int dst = currentInstruction[1].u.operand;
 
     Jump argsCreated = branch32(NotEqual, tagFor(dst), TrustedImm32(JSValue::EmptyValueTag));
-
-    JITStubCall(this, cti_op_create_arguments).call();
-    emitStore(dst, regT1, regT0);
-    emitStore(unmodifiedArgumentsRegister(dst), regT1, regT0);
-
+    callOperation(operationCreateArguments);
+    emitStoreCell(dst, returnValueGPR);
+    emitStoreCell(unmodifiedArgumentsRegister(VirtualRegister(dst)).offset(), returnValueGPR);
     argsCreated.link(this);
 }
 
 void JIT::emit_op_init_lazy_reg(Instruction* currentInstruction)
 {
-    unsigned dst = currentInstruction[1].u.operand;
+    int dst = currentInstruction[1].u.operand;
 
     emitStore(dst, JSValue());
 }
 
 void JIT::emit_op_get_callee(Instruction* currentInstruction)
 {
-    int dst = currentInstruction[1].u.operand;
+    int result = currentInstruction[1].u.operand;
+    WriteBarrierBase<JSCell>* cachedFunction = &currentInstruction[2].u.jsCell;
     emitGetFromCallFrameHeaderPtr(JSStack::Callee, regT0);
+
+    loadPtr(cachedFunction, regT2);
+    addSlowCase(branchPtr(NotEqual, regT0, regT2));
+
     move(TrustedImm32(JSValue::CellTag), regT1);
-    emitValueProfilingSite();
-    emitStore(dst, regT1, regT0);
+    emitStore(result, regT1, regT0);
+}
+
+void JIT::emitSlow_op_get_callee(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
+{
+    linkSlowCase(iter);
+
+    JITSlowPathCall slowPathCall(this, currentInstruction, slow_path_get_callee);
+    slowPathCall.call();
 }
 
 void JIT::emit_op_create_this(Instruction* currentInstruction)
@@ -1175,67 +1072,49 @@ void JIT::emitSlow_op_create_this(Instruction* currentInstruction, Vector<SlowCa
     linkSlowCase(iter); // doesn't have an allocation profile
     linkSlowCase(iter); // allocation failed
 
-    JITStubCall stubCall(this, cti_op_create_this);
-    stubCall.addArgument(TrustedImm32(currentInstruction[3].u.operand));
-    stubCall.call(currentInstruction[1].u.operand);
+    JITSlowPathCall slowPathCall(this, currentInstruction, slow_path_create_this);
+    slowPathCall.call();
 }
 
-void JIT::emit_op_convert_this(Instruction* currentInstruction)
+void JIT::emit_op_to_this(Instruction* currentInstruction)
 {
-    unsigned thisRegister = currentInstruction[1].u.operand;
+    WriteBarrierBase<Structure>* cachedStructure = &currentInstruction[2].u.structure;
+    int thisRegister = currentInstruction[1].u.operand;
 
     emitLoad(thisRegister, regT3, regT2);
 
     addSlowCase(branch32(NotEqual, regT3, TrustedImm32(JSValue::CellTag)));
-    if (shouldEmitProfiling()) {
-        loadPtr(Address(regT2, JSCell::structureOffset()), regT0);
-        move(regT3, regT1);
-        emitValueProfilingSite();
-    }
-    addSlowCase(branchPtr(Equal, Address(regT2, JSCell::structureOffset()), TrustedImmPtr(m_vm->stringStructure.get())));
+    addSlowCase(branch8(NotEqual, Address(regT2, JSCell::typeInfoTypeOffset()), TrustedImm32(FinalObjectType)));
+    loadPtr(Address(regT2, JSCell::structureIDOffset()), regT0);
+    loadPtr(cachedStructure, regT2);
+    addSlowCase(branchPtr(NotEqual, regT0, regT2));
 }
 
-void JIT::emitSlow_op_convert_this(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
+void JIT::emitSlow_op_to_this(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
 {
-    void* globalThis = m_codeBlock->globalObject()->globalThis();
-    unsigned thisRegister = currentInstruction[1].u.operand;
-
     linkSlowCase(iter);
-    if (shouldEmitProfiling()) {
-        move(TrustedImm32(JSValue::UndefinedTag), regT1);
-        move(TrustedImm32(0), regT0);
-    }
-    Jump isNotUndefined = branch32(NotEqual, regT3, TrustedImm32(JSValue::UndefinedTag));
-    emitValueProfilingSite();
-    move(TrustedImmPtr(globalThis), regT0);
-    move(TrustedImm32(JSValue::CellTag), regT1);
-    emitStore(thisRegister, regT1, regT0);
-    emitJumpSlowToHot(jump(), OPCODE_LENGTH(op_convert_this));
-
     linkSlowCase(iter);
-    if (shouldEmitProfiling()) {
-        move(TrustedImm32(JSValue::CellTag), regT1);
-        move(TrustedImmPtr(m_vm->stringStructure.get()), regT0);
-    }
-    isNotUndefined.link(this);
-    emitValueProfilingSite();
-    JITStubCall stubCall(this, cti_op_convert_this);
-    stubCall.addArgument(regT3, regT2);
-    stubCall.call(thisRegister);
+    linkSlowCase(iter);
+    JITSlowPathCall slowPathCall(this, currentInstruction, slow_path_to_this);
+    slowPathCall.call();
 }
 
 void JIT::emit_op_profile_will_call(Instruction* currentInstruction)
 {
-    JITStubCall stubCall(this, cti_op_profile_will_call);
-    stubCall.addArgument(currentInstruction[1].u.operand);
-    stubCall.call();
+    load32(m_vm->enabledProfilerAddress(), regT0);
+    Jump profilerDone = branchTestPtr(Zero, regT0);
+    emitLoad(currentInstruction[1].u.operand, regT1, regT0);
+    callOperation(operationProfileWillCall, regT1, regT0);
+    profilerDone.link(this);
 }
 
 void JIT::emit_op_profile_did_call(Instruction* currentInstruction)
 {
-    JITStubCall stubCall(this, cti_op_profile_did_call);
-    stubCall.addArgument(currentInstruction[1].u.operand);
-    stubCall.call();
+    load32(m_vm->enabledProfilerAddress(), regT0);
+    Jump profilerDone = branchTestPtr(Zero, regT0);
+    emitLoad(currentInstruction[1].u.operand, regT1, regT0);
+    callOperation(operationProfileDidCall, regT1, regT0);
+    profilerDone.link(this);
 }
 
 void JIT::emit_op_get_arguments_length(Instruction* currentInstruction)
@@ -1253,12 +1132,7 @@ void JIT::emitSlow_op_get_arguments_length(Instruction* currentInstruction, Vect
     linkSlowCase(iter);
     int dst = currentInstruction[1].u.operand;
     int base = currentInstruction[2].u.operand;
-    int ident = currentInstruction[3].u.operand;
-    
-    JITStubCall stubCall(this, cti_op_get_by_id_generic);
-    stubCall.addArgument(base);
-    stubCall.addArgument(TrustedImmPtr(&(m_codeBlock->identifier(ident))));
-    stubCall.call(dst);
+    callOperation(operationGetArgumentsLength, dst, base);
 }
 
 void JIT::emit_op_get_argument_by_val(Instruction* currentInstruction)
@@ -1274,7 +1148,6 @@ void JIT::emit_op_get_argument_by_val(Instruction* currentInstruction)
     load32(payloadFor(JSStack::ArgumentCount), regT3);
     addSlowCase(branch32(AboveOrEqual, regT2, regT3));
     
-    neg32(regT2);
     loadPtr(BaseIndex(callFrameRegister, regT2, TimesEight, OBJECT_OFFSETOF(JSValue, u.asBits.payload) + CallFrame::thisArgumentOffset() * static_cast<int>(sizeof(Register))), regT0);
     loadPtr(BaseIndex(callFrameRegister, regT2, TimesEight, OBJECT_OFFSETOF(JSValue, u.asBits.tag) + CallFrame::thisArgumentOffset() * static_cast<int>(sizeof(Register))), regT1);
     emitValueProfilingSite();
@@ -1283,89 +1156,24 @@ void JIT::emit_op_get_argument_by_val(Instruction* currentInstruction)
 
 void JIT::emitSlow_op_get_argument_by_val(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
 {
-    unsigned dst = currentInstruction[1].u.operand;
-    unsigned arguments = currentInstruction[2].u.operand;
-    unsigned property = currentInstruction[3].u.operand;
+    int dst = currentInstruction[1].u.operand;
+    int arguments = currentInstruction[2].u.operand;
+    int property = currentInstruction[3].u.operand;
 
     linkSlowCase(iter);
     Jump skipArgumentsCreation = jump();
 
     linkSlowCase(iter);
     linkSlowCase(iter);
-    JITStubCall(this, cti_op_create_arguments).call();
-    emitStore(arguments, regT1, regT0);
-    emitStore(unmodifiedArgumentsRegister(arguments), regT1, regT0);
+
+    callOperation(operationCreateArguments);
+    emitStoreCell(arguments, returnValueGPR);
+    emitStoreCell(unmodifiedArgumentsRegister(VirtualRegister(arguments)).offset(), returnValueGPR);
     
     skipArgumentsCreation.link(this);
-    JITStubCall stubCall(this, cti_op_get_by_val_generic);
-    stubCall.addArgument(arguments);
-    stubCall.addArgument(property);
-    stubCall.callWithValueProfiling(dst);
-}
-
-void JIT::emit_op_put_to_base(Instruction* currentInstruction)
-{
-    int base = currentInstruction[1].u.operand;
-    int id = currentInstruction[2].u.operand;
-    int value = currentInstruction[3].u.operand;
-
-    PutToBaseOperation* operation = currentInstruction[4].u.putToBaseOperation;
-
-
-    switch (operation->m_kind) {
-    case PutToBaseOperation::GlobalVariablePutChecked:
-        addSlowCase(branchTest8(NonZero, AbsoluteAddress(operation->m_predicatePointer)));
-    case PutToBaseOperation::GlobalVariablePut: {
-        JSGlobalObject* globalObject = m_codeBlock->globalObject();
-        if (operation->m_isDynamic)
-            addSlowCase(branchPtr(NotEqual, payloadFor(base), TrustedImmPtr(globalObject)));
-
-        emitLoad(value, regT1, regT0);
-        storePtr(regT0, reinterpret_cast<char*>(operation->m_registerAddress) + OBJECT_OFFSETOF(JSValue, u.asBits.payload));
-        storePtr(regT1, reinterpret_cast<char*>(operation->m_registerAddress) + OBJECT_OFFSETOF(JSValue, u.asBits.tag));
-        if (Heap::isWriteBarrierEnabled())
-            emitWriteBarrier(globalObject, regT0, regT2, ShouldFilterImmediates, WriteBarrierForVariableAccess);
-        break;
-    }
-    case PutToBaseOperation::VariablePut: {
-        loadPtr(payloadFor(base), regT3);
-        emitLoad(value, regT1, regT0);
-        loadPtr(Address(regT3, JSVariableObject::offsetOfRegisters()), regT2);
-        store32(regT0, Address(regT2, operation->m_offset * sizeof(Register) + OBJECT_OFFSETOF(JSValue, u.asBits.payload)));
-        store32(regT1, Address(regT2, operation->m_offset * sizeof(Register) + OBJECT_OFFSETOF(JSValue, u.asBits.tag)));
-        if (Heap::isWriteBarrierEnabled())
-            emitWriteBarrier(regT3, regT1, regT0, regT2, ShouldFilterImmediates, WriteBarrierForVariableAccess);
-        break;
-    }
-
-    case PutToBaseOperation::GlobalPropertyPut: {
-        JSGlobalObject* globalObject = m_codeBlock->globalObject();
-        loadPtr(payloadFor(base), regT3);
-        emitLoad(value, regT1, regT0);
-        loadPtr(&operation->m_structure, regT2);
-        addSlowCase(branchPtr(NotEqual, Address(regT3, JSCell::structureOffset()), regT2));
-        ASSERT(!operation->m_structure || !operation->m_structure->inlineCapacity());
-        loadPtr(Address(regT3, JSObject::butterflyOffset()), regT2);
-        load32(&operation->m_offsetInButterfly, regT3);
-        storePtr(regT0, BaseIndex(regT2, regT3, TimesEight, OBJECT_OFFSETOF(JSValue, u.asBits.payload)));
-        storePtr(regT1, BaseIndex(regT2, regT3, TimesEight, OBJECT_OFFSETOF(JSValue, u.asBits.tag)));
-        if (Heap::isWriteBarrierEnabled())
-            emitWriteBarrier(globalObject, regT1, regT2, ShouldFilterImmediates, WriteBarrierForVariableAccess);
-        break;
-    }
-
-    case PutToBaseOperation::Uninitialised:
-    case PutToBaseOperation::Readonly:
-    case PutToBaseOperation::Generic:
-        JITStubCall stubCall(this, cti_op_put_to_base);
-
-        stubCall.addArgument(TrustedImm32(base));
-        stubCall.addArgument(TrustedImmPtr(&m_codeBlock->identifier(id)));
-        stubCall.addArgument(TrustedImm32(value));
-        stubCall.addArgument(TrustedImmPtr(operation));
-        stubCall.call();
-        break;
-    }
+    emitLoad(arguments, regT1, regT0);
+    emitLoad(property, regT3, regT2);
+    callOperation(WithProfile, operationGetByValGeneric, dst, regT1, regT0, regT3, regT2);
 }
 
 } // namespace JSC