Example #1
0
static MacroAssemblerCodeRef generateThunkWithJumpTo(VM* vm, void (*target)(), const char *thunkKind)
{
    JSInterfaceJIT jit;
    
    // FIXME: there's probably a better way to do it on X86, but I'm not sure I care.
    jit.move(JSInterfaceJIT::TrustedImmPtr(bitwise_cast<void*>(target)), JSInterfaceJIT::regT0);
    jit.jump(JSInterfaceJIT::regT0);
    
    LinkBuffer patchBuffer(*vm, &jit, GLOBAL_THUNK_ID);
    return FINALIZE_CODE(patchBuffer, ("LLInt %s prologue thunk", thunkKind));
}
Example #2
0
static MacroAssemblerCodeRef linkForGenerator(VM* vm, FunctionPtr lazyLink, FunctionPtr notJSFunction, const char* name)
{
    JSInterfaceJIT jit;

    JSInterfaceJIT::JumpList slowCase;

#if USE(JSVALUE64)
    slowCase.append(jit.emitJumpIfNotJSCell(JSInterfaceJIT::regT0));
    slowCase.append(jit.emitJumpIfNotType(JSInterfaceJIT::regT0, JSInterfaceJIT::regT1, JSFunctionType));
#else // USE(JSVALUE64)
    slowCase.append(jit.branch32(JSInterfaceJIT::NotEqual, JSInterfaceJIT::regT1, JSInterfaceJIT::TrustedImm32(JSValue::CellTag)));
    slowCase.append(jit.emitJumpIfNotType(JSInterfaceJIT::regT0, JSInterfaceJIT::regT1, JSFunctionType));
#endif // USE(JSVALUE64)

    // Finish canonical initialization before JS function call.
    jit.loadPtr(JSInterfaceJIT::Address(JSInterfaceJIT::regT0, JSFunction::offsetOfScopeChain()), JSInterfaceJIT::regT1);
    jit.emitPutCellToCallFrameHeader(JSInterfaceJIT::regT1, JSStack::ScopeChain);

    // Also initialize ReturnPC for use by lazy linking and exceptions.
    jit.preserveReturnAddressAfterCall(JSInterfaceJIT::regT3);
    jit.emitPutToCallFrameHeader(JSInterfaceJIT::regT3, JSStack::ReturnPC);

    jit.storePtr(JSInterfaceJIT::callFrameRegister, &vm->topCallFrame);
    jit.restoreArgumentReference();
    JSInterfaceJIT::Call callLazyLink = jit.call();
    jit.restoreReturnAddressBeforeReturn(JSInterfaceJIT::regT3);
    jit.jump(JSInterfaceJIT::regT0);

    slowCase.link(&jit);
    JSInterfaceJIT::Call callNotJSFunction = generateSlowCaseFor(vm, jit);

    LinkBuffer patchBuffer(*vm, &jit, GLOBAL_THUNK_ID);
    patchBuffer.link(callLazyLink, lazyLink);
    patchBuffer.link(callNotJSFunction, notJSFunction);

    return FINALIZE_CODE(patchBuffer, ("link %s trampoline", name));
}
Example #3
0
MacroAssemblerCodeRef arityFixup(VM* vm)
{
    JSInterfaceJIT jit;

    // We enter with fixup count in regT0
#if USE(JSVALUE64)
#  if CPU(X86_64)
    jit.pop(JSInterfaceJIT::regT4);
#  endif
    jit.addPtr(JSInterfaceJIT::TrustedImm32(-8), JSInterfaceJIT::callFrameRegister, JSInterfaceJIT::regT3);
    jit.load32(JSInterfaceJIT::Address(JSInterfaceJIT::callFrameRegister, JSStack::ArgumentCount * 8), JSInterfaceJIT::regT2);
    jit.add32(JSInterfaceJIT::TrustedImm32(JSStack::CallFrameHeaderSize), JSInterfaceJIT::regT2);

    // Move current frame regT0 number of slots
    JSInterfaceJIT::Label copyLoop(jit.label());
    jit.load64(JSInterfaceJIT::regT3, JSInterfaceJIT::regT1);
    jit.store64(JSInterfaceJIT::regT1, MacroAssembler::BaseIndex(JSInterfaceJIT::regT3, JSInterfaceJIT::regT0, JSInterfaceJIT::TimesEight));
    jit.subPtr(JSInterfaceJIT::TrustedImm32(8), JSInterfaceJIT::regT3);
    jit.branchSub32(MacroAssembler::NonZero, JSInterfaceJIT::TrustedImm32(1), JSInterfaceJIT::regT2).linkTo(copyLoop, &jit);

    // Fill in regT0 missing arg slots with undefined
    jit.move(JSInterfaceJIT::regT0, JSInterfaceJIT::regT2);
    jit.move(JSInterfaceJIT::TrustedImm64(ValueUndefined), JSInterfaceJIT::regT1);
    JSInterfaceJIT::Label fillUndefinedLoop(jit.label());
    jit.store64(JSInterfaceJIT::regT1, MacroAssembler::BaseIndex(JSInterfaceJIT::regT3, JSInterfaceJIT::regT0, JSInterfaceJIT::TimesEight));
    jit.subPtr(JSInterfaceJIT::TrustedImm32(8), JSInterfaceJIT::regT3);
    jit.branchSub32(MacroAssembler::NonZero, JSInterfaceJIT::TrustedImm32(1), JSInterfaceJIT::regT2).linkTo(fillUndefinedLoop, &jit);

    // Adjust call frame register to account for missing args
    jit.lshift32(JSInterfaceJIT::TrustedImm32(3), JSInterfaceJIT::regT0);
    jit.addPtr(JSInterfaceJIT::regT0, JSInterfaceJIT::callFrameRegister);

#  if CPU(X86_64)
    jit.push(JSInterfaceJIT::regT4);
#  endif
    jit.ret();
#else
#  if CPU(X86)
    jit.pop(JSInterfaceJIT::regT4);
#  endif
    jit.addPtr(JSInterfaceJIT::TrustedImm32(-8), JSInterfaceJIT::callFrameRegister, JSInterfaceJIT::regT3);
    jit.load32(JSInterfaceJIT::Address(JSInterfaceJIT::callFrameRegister, JSStack::ArgumentCount * 8), JSInterfaceJIT::regT2);
    jit.add32(JSInterfaceJIT::TrustedImm32(JSStack::CallFrameHeaderSize), JSInterfaceJIT::regT2);

    // Move current frame regT0 number of slots
    JSInterfaceJIT::Label copyLoop(jit.label());
    jit.load32(JSInterfaceJIT::regT3, JSInterfaceJIT::regT1);
    jit.store32(JSInterfaceJIT::regT1, MacroAssembler::BaseIndex(JSInterfaceJIT::regT3, JSInterfaceJIT::regT0, JSInterfaceJIT::TimesEight));
    jit.load32(MacroAssembler::Address(JSInterfaceJIT::regT3, 4), JSInterfaceJIT::regT1);
    jit.store32(JSInterfaceJIT::regT1, MacroAssembler::BaseIndex(JSInterfaceJIT::regT3, JSInterfaceJIT::regT0, JSInterfaceJIT::TimesEight, 4));
    jit.subPtr(JSInterfaceJIT::TrustedImm32(8), JSInterfaceJIT::regT3);
    jit.branchSub32(MacroAssembler::NonZero, JSInterfaceJIT::TrustedImm32(1), JSInterfaceJIT::regT2).linkTo(copyLoop, &jit);

    // Fill in regT0 missing arg slots with undefined
    jit.move(JSInterfaceJIT::regT0, JSInterfaceJIT::regT2);
    JSInterfaceJIT::Label fillUndefinedLoop(jit.label());
    jit.move(JSInterfaceJIT::TrustedImm32(0), JSInterfaceJIT::regT1);
    jit.store32(JSInterfaceJIT::regT1, MacroAssembler::BaseIndex(JSInterfaceJIT::regT3, JSInterfaceJIT::regT0, JSInterfaceJIT::TimesEight));
    jit.move(JSInterfaceJIT::TrustedImm32(JSValue::UndefinedTag), JSInterfaceJIT::regT1);
    jit.store32(JSInterfaceJIT::regT1, MacroAssembler::BaseIndex(JSInterfaceJIT::regT3, JSInterfaceJIT::regT0, JSInterfaceJIT::TimesEight, 4));

    jit.subPtr(JSInterfaceJIT::TrustedImm32(8), JSInterfaceJIT::regT3);
    jit.branchSub32(MacroAssembler::NonZero, JSInterfaceJIT::TrustedImm32(1), JSInterfaceJIT::regT2).linkTo(fillUndefinedLoop, &jit);

    // Adjust call frame register to account for missing args
    jit.lshift32(JSInterfaceJIT::TrustedImm32(3), JSInterfaceJIT::regT0);
    jit.addPtr(JSInterfaceJIT::regT0, JSInterfaceJIT::callFrameRegister);

#  if CPU(X86)
    jit.push(JSInterfaceJIT::regT4);
#  endif
    jit.ret();
#endif

    LinkBuffer patchBuffer(*vm, &jit, GLOBAL_THUNK_ID);
    return FINALIZE_CODE(patchBuffer, ("fixup arity"));
}
Example #4
0
static MacroAssemblerCodeRef nativeForGenerator(VM* vm, CodeSpecializationKind kind)
{
    int executableOffsetToFunction = NativeExecutable::offsetOfNativeFunctionFor(kind);

    JSInterfaceJIT jit;

    jit.emitPutImmediateToCallFrameHeader(0, JSStack::CodeBlock);
    jit.storePtr(JSInterfaceJIT::callFrameRegister, &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.
    jit.emitGetFromCallFrameHeaderPtr(JSStack::CallerFrame, JSInterfaceJIT::regT0);
    jit.emitGetFromCallFrameHeaderPtr(JSStack::ScopeChain, JSInterfaceJIT::regT1, JSInterfaceJIT::regT0);
    jit.emitPutCellToCallFrameHeader(JSInterfaceJIT::regT1, JSStack::ScopeChain);

    jit.peek(JSInterfaceJIT::regT1);
    jit.emitPutToCallFrameHeader(JSInterfaceJIT::regT1, JSStack::ReturnPC);

    // Calling convention:      f(ecx, edx, ...);
    // Host function signature: f(ExecState*);
    jit.move(JSInterfaceJIT::callFrameRegister, X86Registers::ecx);

    jit.subPtr(JSInterfaceJIT::TrustedImm32(16 - sizeof(void*)), JSInterfaceJIT::stackPointerRegister); // Align stack after call.

    // call the function
    jit.emitGetFromCallFrameHeaderPtr(JSStack::Callee, JSInterfaceJIT::regT1);
    jit.loadPtr(JSInterfaceJIT::Address(JSInterfaceJIT::regT1, JSFunction::offsetOfExecutable()), JSInterfaceJIT::regT1);
    jit.move(JSInterfaceJIT::regT0, JSInterfaceJIT::callFrameRegister); // Eagerly restore caller frame register to avoid loading from stack.
    jit.call(JSInterfaceJIT::Address(JSInterfaceJIT::regT1, executableOffsetToFunction));

    jit.addPtr(JSInterfaceJIT::TrustedImm32(16 - sizeof(void*)), JSInterfaceJIT::stackPointerRegister);

#elif CPU(X86_64)
    // Load caller frame's scope chain into this callframe so that whatever we call can
    // get to its global data.
    jit.emitGetFromCallFrameHeaderPtr(JSStack::CallerFrame, JSInterfaceJIT::regT0);
    jit.emitGetFromCallFrameHeaderPtr(JSStack::ScopeChain, JSInterfaceJIT::regT1, JSInterfaceJIT::regT0);
    jit.emitPutCellToCallFrameHeader(JSInterfaceJIT::regT1, JSStack::ScopeChain);

    jit.peek(JSInterfaceJIT::regT1);
    jit.emitPutToCallFrameHeader(JSInterfaceJIT::regT1, JSStack::ReturnPC);

#if !OS(WINDOWS)
    // Calling convention:      f(edi, esi, edx, ecx, ...);
    // Host function signature: f(ExecState*);
    jit.move(JSInterfaceJIT::callFrameRegister, X86Registers::edi);

    jit.subPtr(JSInterfaceJIT::TrustedImm32(16 - sizeof(int64_t)), JSInterfaceJIT::stackPointerRegister); // Align stack after call.

    jit.emitGetFromCallFrameHeaderPtr(JSStack::Callee, X86Registers::esi);
    jit.loadPtr(JSInterfaceJIT::Address(X86Registers::esi, JSFunction::offsetOfExecutable()), X86Registers::r9);
    jit.move(JSInterfaceJIT::regT0, JSInterfaceJIT::callFrameRegister); // Eagerly restore caller frame register to avoid loading from stack.
    jit.call(JSInterfaceJIT::Address(X86Registers::r9, executableOffsetToFunction));

    jit.addPtr(JSInterfaceJIT::TrustedImm32(16 - sizeof(int64_t)), JSInterfaceJIT::stackPointerRegister);
#else
    // Calling convention:      f(ecx, edx, r8, r9, ...);
    // Host function signature: f(ExecState*);
    jit.move(JSInterfaceJIT::callFrameRegister, X86Registers::ecx);

    // Leave space for the callee parameter home addresses and align the stack.
    jit.subPtr(JSInterfaceJIT::TrustedImm32(4 * sizeof(int64_t) + 16 - sizeof(int64_t)), JSInterfaceJIT::stackPointerRegister);

    jit.emitGetFromCallFrameHeaderPtr(JSStack::Callee, X86Registers::edx);
    jit.loadPtr(JSInterfaceJIT::Address(X86Registers::edx, JSFunction::offsetOfExecutable()), X86Registers::r9);
    jit.move(JSInterfaceJIT::regT0, JSInterfaceJIT::callFrameRegister); // Eagerly restore caller frame register to avoid loading from stack.
    jit.call(JSInterfaceJIT::Address(X86Registers::r9, executableOffsetToFunction));

    jit.addPtr(JSInterfaceJIT::TrustedImm32(4 * sizeof(int64_t) + 16 - sizeof(int64_t)), JSInterfaceJIT::stackPointerRegister);
#endif

#elif CPU(ARM)
    // Load caller frame's scope chain into this callframe so that whatever we call can
    // get to its global data.
    jit.emitGetFromCallFrameHeaderPtr(JSStack::CallerFrame, JSInterfaceJIT::regT2);
    jit.emitGetFromCallFrameHeaderPtr(JSStack::ScopeChain, JSInterfaceJIT::regT1, JSInterfaceJIT::regT2);
    jit.emitPutCellToCallFrameHeader(JSInterfaceJIT::regT1, JSStack::ScopeChain);

    jit.preserveReturnAddressAfterCall(JSInterfaceJIT::regT3); // Callee preserved
    jit.emitPutToCallFrameHeader(JSInterfaceJIT::regT3, JSStack::ReturnPC);

    // Calling convention:      f(r0 == regT0, r1 == regT1, ...);
    // Host function signature: f(ExecState*);
    jit.move(JSInterfaceJIT::callFrameRegister, ARMRegisters::r0);

    jit.emitGetFromCallFrameHeaderPtr(JSStack::Callee, ARMRegisters::r1);
    jit.move(JSInterfaceJIT::regT2, JSInterfaceJIT::callFrameRegister); // Eagerly restore caller frame register to avoid loading from stack.
    jit.loadPtr(JSInterfaceJIT::Address(ARMRegisters::r1, JSFunction::offsetOfExecutable()), JSInterfaceJIT::regT2);
    jit.call(JSInterfaceJIT::Address(JSInterfaceJIT::regT2, executableOffsetToFunction));

    jit.restoreReturnAddressBeforeReturn(JSInterfaceJIT::regT3);

#elif CPU(SH4)
    // Load caller frame's scope chain into this callframe so that whatever we call can
    // get to its global data.
    jit.emitGetFromCallFrameHeaderPtr(JSStack::CallerFrame, JSInterfaceJIT::regT2);
    jit.emitGetFromCallFrameHeaderPtr(JSStack::ScopeChain, JSInterfaceJIT::regT1, JSInterfaceJIT::regT2);
    jit.emitPutCellToCallFrameHeader(JSInterfaceJIT::regT1, JSStack::ScopeChain);

    jit.preserveReturnAddressAfterCall(JSInterfaceJIT::regT3); // Callee preserved
    jit.emitPutToCallFrameHeader(JSInterfaceJIT::regT3, JSStack::ReturnPC);

    // Calling convention: f(r0 == regT4, r1 == regT5, ...);
    // Host function signature: f(ExecState*);
    jit.move(JSInterfaceJIT::callFrameRegister, JSInterfaceJIT::regT4);

    jit.emitGetFromCallFrameHeaderPtr(JSStack::Callee, JSInterfaceJIT::regT5);
    jit.move(JSInterfaceJIT::regT2, JSInterfaceJIT::callFrameRegister); // Eagerly restore caller frame register to avoid loading from stack.
    jit.loadPtr(JSInterfaceJIT::Address(JSInterfaceJIT::regT5, JSFunction::offsetOfExecutable()), JSInterfaceJIT::regT2);

    jit.call(JSInterfaceJIT::Address(JSInterfaceJIT::regT2, executableOffsetToFunction), JSInterfaceJIT::regT0);
    jit.restoreReturnAddressBeforeReturn(JSInterfaceJIT::regT3);

#elif CPU(MIPS)
    // Load caller frame's scope chain into this callframe so that whatever we call can
    // get to its global data.
    jit.emitGetFromCallFrameHeaderPtr(JSStack::CallerFrame, JSInterfaceJIT::regT0);
    jit.emitGetFromCallFrameHeaderPtr(JSStack::ScopeChain, JSInterfaceJIT::regT1, JSInterfaceJIT::regT0);
    jit.emitPutCellToCallFrameHeader(JSInterfaceJIT::regT1, JSStack::ScopeChain);

    jit.preserveReturnAddressAfterCall(JSInterfaceJIT::regT3); // Callee preserved
    jit.emitPutToCallFrameHeader(JSInterfaceJIT::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
    jit.subPtr(JSInterfaceJIT::TrustedImm32(16), JSInterfaceJIT::stackPointerRegister);

    // Setup arg0
    jit.move(JSInterfaceJIT::callFrameRegister, MIPSRegisters::a0);

    // Call
    jit.emitGetFromCallFrameHeaderPtr(JSStack::Callee, MIPSRegisters::a2);
    jit.loadPtr(JSInterfaceJIT::Address(MIPSRegisters::a2, JSFunction::offsetOfExecutable()), JSInterfaceJIT::regT2);
    jit.move(JSInterfaceJIT::regT0, JSInterfaceJIT::callFrameRegister); // Eagerly restore caller frame register to avoid loading from stack.
    jit.call(JSInterfaceJIT::Address(JSInterfaceJIT::regT2, executableOffsetToFunction));

    // Restore stack space
    jit.addPtr(JSInterfaceJIT::TrustedImm32(16), JSInterfaceJIT::stackPointerRegister);

    jit.restoreReturnAddressBeforeReturn(JSInterfaceJIT::regT3);
#else
#error "JIT not supported on this platform."
    UNUSED_PARAM(executableOffsetToFunction);
    breakpoint();
#endif

    // Check for an exception
#if USE(JSVALUE64)
    jit.load64(&(vm->exception), JSInterfaceJIT::regT2);
    JSInterfaceJIT::Jump exceptionHandler = jit.branchTest64(JSInterfaceJIT::NonZero, JSInterfaceJIT::regT2);
#else
    JSInterfaceJIT::Jump exceptionHandler = jit.branch32(
            JSInterfaceJIT::NotEqual,
            JSInterfaceJIT::AbsoluteAddress(reinterpret_cast<char*>(&vm->exception) + OBJECT_OFFSETOF(EncodedValueDescriptor, asBits.tag)),
            JSInterfaceJIT::TrustedImm32(JSValue::EmptyValueTag));
#endif

    // Return.
    jit.ret();

    // Handle an exception
    exceptionHandler.link(&jit);

    // Grab the return address.
    jit.preserveReturnAddressAfterCall(JSInterfaceJIT::regT1);

    jit.move(JSInterfaceJIT::TrustedImmPtr(&vm->exceptionLocation), JSInterfaceJIT::regT2);
    jit.storePtr(JSInterfaceJIT::regT1, JSInterfaceJIT::regT2);

    jit.storePtr(JSInterfaceJIT::callFrameRegister, &vm->topCallFrame);

    jit.move(JSInterfaceJIT::TrustedImmPtr(FunctionPtr(ctiVMThrowTrampolineSlowpath).value()), JSInterfaceJIT::regT1);
    jit.jump(JSInterfaceJIT::regT1);

    LinkBuffer patchBuffer(*vm, &jit, GLOBAL_THUNK_ID);
    return FINALIZE_CODE(patchBuffer, ("native %s trampoline", toCString(kind).data()));
}
Example #5
0
MacroAssemblerCodeRef stringLengthTrampolineGenerator(VM* vm)
{
    JSInterfaceJIT jit;

#if USE(JSVALUE64)
    // Check eax is a string
    JSInterfaceJIT::Jump failureCases1 = jit.emitJumpIfNotJSCell(JSInterfaceJIT::regT0);
    JSInterfaceJIT::Jump failureCases2 = jit.branchPtr(
            JSInterfaceJIT::NotEqual, JSInterfaceJIT::Address(
                JSInterfaceJIT::regT0, JSCell::structureOffset()),
            JSInterfaceJIT::TrustedImmPtr(vm->stringStructure.get()));

    // Checks out okay! - get the length from the Ustring.
    jit.load32(
        JSInterfaceJIT::Address(JSInterfaceJIT::regT0, JSString::offsetOfLength()),
        JSInterfaceJIT::regT0);

    JSInterfaceJIT::Jump failureCases3 = jit.branch32(
            JSInterfaceJIT::LessThan, JSInterfaceJIT::regT0, JSInterfaceJIT::TrustedImm32(0));

    // regT0 contains a 64 bit value (is positive, is zero extended) so we don't need sign extend here.
    jit.emitFastArithIntToImmNoCheck(JSInterfaceJIT::regT0, JSInterfaceJIT::regT0);

#else // USE(JSVALUE64)
    // regT0 holds payload, regT1 holds tag

    JSInterfaceJIT::Jump failureCases1 = jit.branch32(
            JSInterfaceJIT::NotEqual, JSInterfaceJIT::regT1,
            JSInterfaceJIT::TrustedImm32(JSValue::CellTag));
    JSInterfaceJIT::Jump failureCases2 = jit.branchPtr(
            JSInterfaceJIT::NotEqual,
            JSInterfaceJIT::Address(JSInterfaceJIT::regT0, JSCell::structureOffset()),
            JSInterfaceJIT::TrustedImmPtr(vm->stringStructure.get()));

    // Checks out okay! - get the length from the Ustring.
    jit.load32(
        JSInterfaceJIT::Address(JSInterfaceJIT::regT0, JSString::offsetOfLength()),
        JSInterfaceJIT::regT2);

    JSInterfaceJIT::Jump failureCases3 = jit.branch32(
            JSInterfaceJIT::Above, JSInterfaceJIT::regT2, JSInterfaceJIT::TrustedImm32(INT_MAX));
    jit.move(JSInterfaceJIT::regT2, JSInterfaceJIT::regT0);
    jit.move(JSInterfaceJIT::TrustedImm32(JSValue::Int32Tag), JSInterfaceJIT::regT1);
#endif // USE(JSVALUE64)

    jit.ret();

    JSInterfaceJIT::Call failureCases1Call = jit.makeTailRecursiveCall(failureCases1);
    JSInterfaceJIT::Call failureCases2Call = jit.makeTailRecursiveCall(failureCases2);
    JSInterfaceJIT::Call failureCases3Call = jit.makeTailRecursiveCall(failureCases3);

    LinkBuffer patchBuffer(*vm, &jit, GLOBAL_THUNK_ID);

    patchBuffer.link(failureCases1Call, FunctionPtr(cti_op_get_by_id_string_fail));
    patchBuffer.link(failureCases2Call, FunctionPtr(cti_op_get_by_id_string_fail));
    patchBuffer.link(failureCases3Call, FunctionPtr(cti_op_get_by_id_string_fail));

    return FINALIZE_CODE(patchBuffer, ("string length trampoline"));
}
Example #6
0
static MacroAssemblerCodeRef virtualForGenerator(VM* vm, FunctionPtr compile, FunctionPtr notJSFunction, const char* name, CodeSpecializationKind kind)
{
    JSInterfaceJIT jit;

    JSInterfaceJIT::JumpList slowCase;

#if USE(JSVALUE64)
    slowCase.append(jit.emitJumpIfNotJSCell(JSInterfaceJIT::regT0));
#else // USE(JSVALUE64)
    slowCase.append(jit.branch32(JSInterfaceJIT::NotEqual, JSInterfaceJIT::regT1, JSInterfaceJIT::TrustedImm32(JSValue::CellTag)));
#endif // USE(JSVALUE64)
    slowCase.append(jit.emitJumpIfNotType(JSInterfaceJIT::regT0, JSInterfaceJIT::regT1, JSFunctionType));

    // Finish canonical initialization before JS function call.
    jit.loadPtr(JSInterfaceJIT::Address(JSInterfaceJIT::regT0, JSFunction::offsetOfScopeChain()), JSInterfaceJIT::regT1);
    jit.emitPutCellToCallFrameHeader(JSInterfaceJIT::regT1, JSStack::ScopeChain);

    jit.loadPtr(JSInterfaceJIT::Address(JSInterfaceJIT::regT0, JSFunction::offsetOfExecutable()), JSInterfaceJIT::regT2);
    JSInterfaceJIT::Jump hasCodeBlock1 = jit.branch32(JSInterfaceJIT::GreaterThanOrEqual, JSInterfaceJIT::Address(JSInterfaceJIT::regT2, FunctionExecutable::offsetOfNumParametersFor(kind)), JSInterfaceJIT::TrustedImm32(0));
    jit.preserveReturnAddressAfterCall(JSInterfaceJIT::regT3);
    jit.storePtr(JSInterfaceJIT::callFrameRegister, &vm->topCallFrame);
    jit.restoreArgumentReference();
    JSInterfaceJIT::Call callCompile = jit.call();
    jit.restoreReturnAddressBeforeReturn(JSInterfaceJIT::regT3);
    jit.loadPtr(JSInterfaceJIT::Address(JSInterfaceJIT::regT0, JSFunction::offsetOfExecutable()), JSInterfaceJIT::regT2);

    hasCodeBlock1.link(&jit);
    jit.loadPtr(JSInterfaceJIT::Address(JSInterfaceJIT::regT2, FunctionExecutable::offsetOfJITCodeWithArityCheckFor(kind)), JSInterfaceJIT::regT0);
#if !ASSERT_DISABLED
    JSInterfaceJIT::Jump ok = jit.branchTestPtr(JSInterfaceJIT::NonZero, JSInterfaceJIT::regT0);
    jit.breakpoint();
    ok.link(&jit);
#endif
    jit.jump(JSInterfaceJIT::regT0);

    slowCase.link(&jit);
    JSInterfaceJIT::Call callNotJSFunction = generateSlowCaseFor(vm, jit);

    LinkBuffer patchBuffer(*vm, &jit, GLOBAL_THUNK_ID);
    patchBuffer.link(callCompile, compile);
    patchBuffer.link(callNotJSFunction, notJSFunction);

    return FINALIZE_CODE(patchBuffer, ("virtual %s trampoline", name));
}