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Diffstat (limited to 'deps/v8/src/x64/macro-assembler-x64.cc')
-rw-r--r--deps/v8/src/x64/macro-assembler-x64.cc599
1 files changed, 579 insertions, 20 deletions
diff --git a/deps/v8/src/x64/macro-assembler-x64.cc b/deps/v8/src/x64/macro-assembler-x64.cc
index 54c299dbf..c47bfccf1 100644
--- a/deps/v8/src/x64/macro-assembler-x64.cc
+++ b/deps/v8/src/x64/macro-assembler-x64.cc
@@ -29,7 +29,9 @@
#include "bootstrapper.h"
#include "codegen-inl.h"
+#include "assembler-x64.h"
#include "macro-assembler-x64.h"
+#include "debug.h"
namespace v8 {
namespace internal {
@@ -43,8 +45,152 @@ MacroAssembler::MacroAssembler(void* buffer, int size)
}
-void MacroAssembler::TailCallRuntime(ExternalReference const& a, int b) {
- UNIMPLEMENTED();
+void MacroAssembler::Assert(Condition cc, const char* msg) {
+ if (FLAG_debug_code) Check(cc, msg);
+}
+
+
+void MacroAssembler::Check(Condition cc, const char* msg) {
+ Label L;
+ j(cc, &L);
+ Abort(msg);
+ // will not return here
+ bind(&L);
+}
+
+
+void MacroAssembler::ConstructAndTestJSFunction() {
+ const int initial_buffer_size = 4 * KB;
+ char* buffer = new char[initial_buffer_size];
+ MacroAssembler masm(buffer, initial_buffer_size);
+
+ const uint64_t secret = V8_INT64_C(0xdeadbeefcafebabe);
+ Handle<String> constant =
+ Factory::NewStringFromAscii(Vector<const char>("451", 3), TENURED);
+#define __ ACCESS_MASM((&masm))
+ // Construct a simple JSfunction here, using Assembler and MacroAssembler
+ // commands.
+ __ movq(rax, constant, RelocInfo::EMBEDDED_OBJECT);
+ __ push(rax);
+ __ CallRuntime(Runtime::kStringParseFloat, 1);
+ __ movq(kScratchRegister, secret, RelocInfo::NONE);
+ __ addq(rax, kScratchRegister);
+ __ ret(0);
+#undef __
+ CodeDesc desc;
+ masm.GetCode(&desc);
+ Code::Flags flags = Code::ComputeFlags(Code::FUNCTION);
+ Object* code = Heap::CreateCode(desc, NULL, flags, Handle<Object>::null());
+ if (!code->IsFailure()) {
+ Handle<Code> code_handle(Code::cast(code));
+ Handle<String> name =
+ Factory::NewStringFromAscii(Vector<const char>("foo", 3), NOT_TENURED);
+ Handle<JSFunction> function =
+ Factory::NewFunction(name,
+ JS_FUNCTION_TYPE,
+ JSObject::kHeaderSize,
+ code_handle,
+ true);
+ bool pending_exceptions;
+ Handle<Object> result =
+ Execution::Call(function,
+ Handle<Object>::cast(function),
+ 0,
+ NULL,
+ &pending_exceptions);
+ CHECK(result->IsSmi());
+ CHECK(secret + (451 << kSmiTagSize) == reinterpret_cast<uint64_t>(*result));
+ }
+}
+
+
+void MacroAssembler::Abort(const char* msg) {
+ // We want to pass the msg string like a smi to avoid GC
+ // problems, however msg is not guaranteed to be aligned
+ // properly. Instead, we pass an aligned pointer that is
+ // a proper v8 smi, but also pass the alignment difference
+ // from the real pointer as a smi.
+ intptr_t p1 = reinterpret_cast<intptr_t>(msg);
+ intptr_t p0 = (p1 & ~kSmiTagMask) + kSmiTag;
+ // Note: p0 might not be a valid Smi *value*, but it has a valid Smi tag.
+ ASSERT(reinterpret_cast<Object*>(p0)->IsSmi());
+#ifdef DEBUG
+ if (msg != NULL) {
+ RecordComment("Abort message: ");
+ RecordComment(msg);
+ }
+#endif
+ push(rax);
+ movq(kScratchRegister, p0, RelocInfo::NONE);
+ push(kScratchRegister);
+ movq(kScratchRegister,
+ reinterpret_cast<intptr_t>(Smi::FromInt(p1 - p0)),
+ RelocInfo::NONE);
+ push(kScratchRegister);
+ CallRuntime(Runtime::kAbort, 2);
+ // will not return here
+}
+
+
+void MacroAssembler::CallStub(CodeStub* stub) {
+ ASSERT(allow_stub_calls()); // calls are not allowed in some stubs
+ movq(kScratchRegister, stub->GetCode(), RelocInfo::CODE_TARGET);
+ call(kScratchRegister);
+}
+
+
+void MacroAssembler::StubReturn(int argc) {
+ ASSERT(argc >= 1 && generating_stub());
+ ret((argc - 1) * kPointerSize);
+}
+
+
+void MacroAssembler::IllegalOperation(int num_arguments) {
+ if (num_arguments > 0) {
+ addq(rsp, Immediate(num_arguments * kPointerSize));
+ }
+ movq(rax, Factory::undefined_value(), RelocInfo::EMBEDDED_OBJECT);
+}
+
+
+void MacroAssembler::CallRuntime(Runtime::FunctionId id, int num_arguments) {
+ CallRuntime(Runtime::FunctionForId(id), num_arguments);
+}
+
+
+void MacroAssembler::CallRuntime(Runtime::Function* f, int num_arguments) {
+ // If the expected number of arguments of the runtime function is
+ // constant, we check that the actual number of arguments match the
+ // expectation.
+ if (f->nargs >= 0 && f->nargs != num_arguments) {
+ IllegalOperation(num_arguments);
+ return;
+ }
+
+ Runtime::FunctionId function_id =
+ static_cast<Runtime::FunctionId>(f->stub_id);
+ RuntimeStub stub(function_id, num_arguments);
+ CallStub(&stub);
+}
+
+
+void MacroAssembler::TailCallRuntime(ExternalReference const& ext,
+ int num_arguments) {
+ // TODO(1236192): Most runtime routines don't need the number of
+ // arguments passed in because it is constant. At some point we
+ // should remove this need and make the runtime routine entry code
+ // smarter.
+ movq(rax, Immediate(num_arguments));
+ JumpToBuiltin(ext);
+}
+
+
+void MacroAssembler::JumpToBuiltin(const ExternalReference& ext) {
+ // Set the entry point and jump to the C entry runtime stub.
+ movq(rbx, ext);
+ CEntryStub ces;
+ movq(kScratchRegister, ces.GetCode(), RelocInfo::CODE_TARGET);
+ jmp(kScratchRegister);
}
@@ -71,18 +217,43 @@ void MacroAssembler::Set(const Operand& dst, int64_t x) {
}
+void MacroAssembler::Jump(ExternalReference ext) {
+ movq(kScratchRegister, ext);
+ jmp(kScratchRegister);
+}
+
+
+void MacroAssembler::Jump(Address destination, RelocInfo::Mode rmode) {
+ movq(kScratchRegister, destination, rmode);
+ jmp(kScratchRegister);
+}
+
+
+void MacroAssembler::Call(ExternalReference ext) {
+ movq(kScratchRegister, ext);
+ call(kScratchRegister);
+}
+
+
+void MacroAssembler::Call(Address destination, RelocInfo::Mode rmode) {
+ movq(kScratchRegister, destination, rmode);
+ call(kScratchRegister);
+}
+
+
void MacroAssembler::PushTryHandler(CodeLocation try_location,
HandlerType type) {
- // The pc (return address) is already on TOS.
- // This code pushes state, code, frame pointer and parameter pointer.
- // Check that they are expected next on the stack, int that order.
+ // Adjust this code if not the case.
+ ASSERT(StackHandlerConstants::kSize == 4 * kPointerSize);
+
+ // The pc (return address) is already on TOS. This code pushes state,
+ // frame pointer and current handler. Check that they are expected
+ // next on the stack, in that order.
ASSERT_EQ(StackHandlerConstants::kStateOffset,
StackHandlerConstants::kPCOffset - kPointerSize);
- ASSERT_EQ(StackHandlerConstants::kCodeOffset,
- StackHandlerConstants::kStateOffset - kPointerSize);
ASSERT_EQ(StackHandlerConstants::kFPOffset,
- StackHandlerConstants::kCodeOffset - kPointerSize);
- ASSERT_EQ(StackHandlerConstants::kPPOffset,
+ StackHandlerConstants::kStateOffset - kPointerSize);
+ ASSERT_EQ(StackHandlerConstants::kNextOffset,
StackHandlerConstants::kFPOffset - kPointerSize);
if (try_location == IN_JAVASCRIPT) {
@@ -91,26 +262,414 @@ void MacroAssembler::PushTryHandler(CodeLocation try_location,
} else {
push(Immediate(StackHandler::TRY_FINALLY));
}
- push(Immediate(Smi::FromInt(StackHandler::kCodeNotPresent)));
push(rbp);
- push(rdi);
} else {
ASSERT(try_location == IN_JS_ENTRY);
- // The parameter pointer is meaningless here and ebp does not
- // point to a JS frame. So we save NULL for both pp and ebp. We
- // expect the code throwing an exception to check ebp before
- // dereferencing it to restore the context.
+ // The frame pointer does not point to a JS frame so we save NULL
+ // for rbp. We expect the code throwing an exception to check rbp
+ // before dereferencing it to restore the context.
push(Immediate(StackHandler::ENTRY));
- push(Immediate(Smi::FromInt(StackHandler::kCodeNotPresent)));
- push(Immediate(0)); // NULL frame pointer
- push(Immediate(0)); // NULL parameter pointer
+ push(Immediate(0)); // NULL frame pointer.
}
+ // Save the current handler.
movq(kScratchRegister, ExternalReference(Top::k_handler_address));
- // Cached TOS.
- movq(rax, Operand(kScratchRegister, 0));
+ push(Operand(kScratchRegister, 0));
// Link this handler.
movq(Operand(kScratchRegister, 0), rsp);
}
+void MacroAssembler::Ret() {
+ ret(0);
+}
+
+
+void MacroAssembler::CmpObjectType(Register heap_object,
+ InstanceType type,
+ Register map) {
+ movq(map, FieldOperand(heap_object, HeapObject::kMapOffset));
+ CmpInstanceType(map, type);
+}
+
+
+void MacroAssembler::CmpInstanceType(Register map, InstanceType type) {
+ cmpb(FieldOperand(map, Map::kInstanceTypeOffset),
+ Immediate(static_cast<int8_t>(type)));
+}
+
+
+
+void MacroAssembler::SetCounter(StatsCounter* counter, int value) {
+ if (FLAG_native_code_counters && counter->Enabled()) {
+ movq(kScratchRegister, ExternalReference(counter));
+ movl(Operand(kScratchRegister, 0), Immediate(value));
+ }
+}
+
+
+void MacroAssembler::IncrementCounter(StatsCounter* counter, int value) {
+ ASSERT(value > 0);
+ if (FLAG_native_code_counters && counter->Enabled()) {
+ movq(kScratchRegister, ExternalReference(counter));
+ Operand operand(kScratchRegister, 0);
+ if (value == 1) {
+ incl(operand);
+ } else {
+ addl(operand, Immediate(value));
+ }
+ }
+}
+
+
+void MacroAssembler::DecrementCounter(StatsCounter* counter, int value) {
+ ASSERT(value > 0);
+ if (FLAG_native_code_counters && counter->Enabled()) {
+ movq(kScratchRegister, ExternalReference(counter));
+ Operand operand(kScratchRegister, 0);
+ if (value == 1) {
+ decl(operand);
+ } else {
+ subl(operand, Immediate(value));
+ }
+ }
+}
+
+
+#ifdef ENABLE_DEBUGGER_SUPPORT
+
+void MacroAssembler::PushRegistersFromMemory(RegList regs) {
+ ASSERT((regs & ~kJSCallerSaved) == 0);
+ // Push the content of the memory location to the stack.
+ for (int i = 0; i < kNumJSCallerSaved; i++) {
+ int r = JSCallerSavedCode(i);
+ if ((regs & (1 << r)) != 0) {
+ ExternalReference reg_addr =
+ ExternalReference(Debug_Address::Register(i));
+ movq(kScratchRegister, reg_addr);
+ push(Operand(kScratchRegister, 0));
+ }
+ }
+}
+
+void MacroAssembler::SaveRegistersToMemory(RegList regs) {
+ ASSERT((regs & ~kJSCallerSaved) == 0);
+ // Copy the content of registers to memory location.
+ for (int i = 0; i < kNumJSCallerSaved; i++) {
+ int r = JSCallerSavedCode(i);
+ if ((regs & (1 << r)) != 0) {
+ Register reg = { r };
+ ExternalReference reg_addr =
+ ExternalReference(Debug_Address::Register(i));
+ movq(kScratchRegister, reg_addr);
+ movq(Operand(kScratchRegister, 0), reg);
+ }
+ }
+}
+
+
+void MacroAssembler::RestoreRegistersFromMemory(RegList regs) {
+ ASSERT((regs & ~kJSCallerSaved) == 0);
+ // Copy the content of memory location to registers.
+ for (int i = kNumJSCallerSaved - 1; i >= 0; i--) {
+ int r = JSCallerSavedCode(i);
+ if ((regs & (1 << r)) != 0) {
+ Register reg = { r };
+ ExternalReference reg_addr =
+ ExternalReference(Debug_Address::Register(i));
+ movq(kScratchRegister, reg_addr);
+ movq(reg, Operand(kScratchRegister, 0));
+ }
+ }
+}
+
+
+void MacroAssembler::PopRegistersToMemory(RegList regs) {
+ ASSERT((regs & ~kJSCallerSaved) == 0);
+ // Pop the content from the stack to the memory location.
+ for (int i = kNumJSCallerSaved - 1; i >= 0; i--) {
+ int r = JSCallerSavedCode(i);
+ if ((regs & (1 << r)) != 0) {
+ ExternalReference reg_addr =
+ ExternalReference(Debug_Address::Register(i));
+ movq(kScratchRegister, reg_addr);
+ pop(Operand(kScratchRegister, 0));
+ }
+ }
+}
+
+
+void MacroAssembler::CopyRegistersFromStackToMemory(Register base,
+ Register scratch,
+ RegList regs) {
+ ASSERT(!scratch.is(kScratchRegister));
+ ASSERT(!base.is(kScratchRegister));
+ ASSERT(!base.is(scratch));
+ ASSERT((regs & ~kJSCallerSaved) == 0);
+ // Copy the content of the stack to the memory location and adjust base.
+ for (int i = kNumJSCallerSaved - 1; i >= 0; i--) {
+ int r = JSCallerSavedCode(i);
+ if ((regs & (1 << r)) != 0) {
+ movq(scratch, Operand(base, 0));
+ ExternalReference reg_addr =
+ ExternalReference(Debug_Address::Register(i));
+ movq(kScratchRegister, reg_addr);
+ movq(Operand(kScratchRegister, 0), scratch);
+ lea(base, Operand(base, kPointerSize));
+ }
+ }
+}
+
+#endif // ENABLE_DEBUGGER_SUPPORT
+
+
+void MacroAssembler::InvokePrologue(const ParameterCount& expected,
+ const ParameterCount& actual,
+ Handle<Code> code_constant,
+ Register code_register,
+ Label* done,
+ InvokeFlag flag) {
+ bool definitely_matches = false;
+ Label invoke;
+ if (expected.is_immediate()) {
+ ASSERT(actual.is_immediate());
+ if (expected.immediate() == actual.immediate()) {
+ definitely_matches = true;
+ } else {
+ movq(rax, Immediate(actual.immediate()));
+ if (expected.immediate() ==
+ SharedFunctionInfo::kDontAdaptArgumentsSentinel) {
+ // Don't worry about adapting arguments for built-ins that
+ // don't want that done. Skip adaption code by making it look
+ // like we have a match between expected and actual number of
+ // arguments.
+ definitely_matches = true;
+ } else {
+ movq(rbx, Immediate(expected.immediate()));
+ }
+ }
+ } else {
+ if (actual.is_immediate()) {
+ // Expected is in register, actual is immediate. This is the
+ // case when we invoke function values without going through the
+ // IC mechanism.
+ cmpq(expected.reg(), Immediate(actual.immediate()));
+ j(equal, &invoke);
+ ASSERT(expected.reg().is(rbx));
+ movq(rax, Immediate(actual.immediate()));
+ } else if (!expected.reg().is(actual.reg())) {
+ // Both expected and actual are in (different) registers. This
+ // is the case when we invoke functions using call and apply.
+ cmpq(expected.reg(), actual.reg());
+ j(equal, &invoke);
+ ASSERT(actual.reg().is(rax));
+ ASSERT(expected.reg().is(rbx));
+ }
+ }
+
+ if (!definitely_matches) {
+ Handle<Code> adaptor =
+ Handle<Code>(Builtins::builtin(Builtins::ArgumentsAdaptorTrampoline));
+ if (!code_constant.is_null()) {
+ movq(rdx, code_constant, RelocInfo::EMBEDDED_OBJECT);
+ addq(rdx, Immediate(Code::kHeaderSize - kHeapObjectTag));
+ } else if (!code_register.is(rdx)) {
+ movq(rdx, code_register);
+ }
+
+ movq(kScratchRegister, adaptor, RelocInfo::CODE_TARGET);
+ if (flag == CALL_FUNCTION) {
+ call(kScratchRegister);
+ jmp(done);
+ } else {
+ jmp(kScratchRegister);
+ }
+ bind(&invoke);
+ }
+}
+
+
+
+
+void MacroAssembler::InvokeCode(Register code,
+ const ParameterCount& expected,
+ const ParameterCount& actual,
+ InvokeFlag flag) {
+ Label done;
+ InvokePrologue(expected, actual, Handle<Code>::null(), code, &done, flag);
+ if (flag == CALL_FUNCTION) {
+ call(code);
+ } else {
+ ASSERT(flag == JUMP_FUNCTION);
+ jmp(code);
+ }
+ bind(&done);
+}
+
+
+void MacroAssembler::InvokeCode(Handle<Code> code,
+ const ParameterCount& expected,
+ const ParameterCount& actual,
+ RelocInfo::Mode rmode,
+ InvokeFlag flag) {
+ Label done;
+ Register dummy = rax;
+ InvokePrologue(expected, actual, code, dummy, &done, flag);
+ movq(kScratchRegister, code, rmode);
+ if (flag == CALL_FUNCTION) {
+ call(kScratchRegister);
+ } else {
+ ASSERT(flag == JUMP_FUNCTION);
+ jmp(kScratchRegister);
+ }
+ bind(&done);
+}
+
+
+void MacroAssembler::InvokeFunction(Register function,
+ const ParameterCount& actual,
+ InvokeFlag flag) {
+ ASSERT(function.is(rdi));
+ movq(rdx, FieldOperand(function, JSFunction::kSharedFunctionInfoOffset));
+ movq(rsi, FieldOperand(function, JSFunction::kContextOffset));
+ movl(rbx, FieldOperand(rdx, SharedFunctionInfo::kFormalParameterCountOffset));
+ movq(rdx, FieldOperand(rdx, SharedFunctionInfo::kCodeOffset));
+ // Advances rdx to the end of the Code object headers, to the start of
+ // the executable code.
+ lea(rdx, FieldOperand(rdx, Code::kHeaderSize));
+
+ ParameterCount expected(rbx);
+ InvokeCode(rdx, expected, actual, flag);
+}
+
+
+void MacroAssembler::EnterFrame(StackFrame::Type type) {
+ push(rbp);
+ movq(rbp, rsp);
+ push(rsi); // Context.
+ push(Immediate(Smi::FromInt(type)));
+ movq(kScratchRegister, CodeObject(), RelocInfo::EMBEDDED_OBJECT);
+ push(kScratchRegister);
+ if (FLAG_debug_code) {
+ movq(kScratchRegister,
+ Factory::undefined_value(),
+ RelocInfo::EMBEDDED_OBJECT);
+ cmpq(Operand(rsp, 0), kScratchRegister);
+ Check(not_equal, "code object not properly patched");
+ }
+}
+
+
+void MacroAssembler::LeaveFrame(StackFrame::Type type) {
+ if (FLAG_debug_code) {
+ movq(kScratchRegister, Immediate(Smi::FromInt(type)));
+ cmpq(Operand(rbp, StandardFrameConstants::kMarkerOffset), kScratchRegister);
+ Check(equal, "stack frame types must match");
+ }
+ movq(rsp, rbp);
+ pop(rbp);
+}
+
+
+
+void MacroAssembler::EnterExitFrame(StackFrame::Type type) {
+ ASSERT(type == StackFrame::EXIT || type == StackFrame::EXIT_DEBUG);
+
+ // Setup the frame structure on the stack.
+ ASSERT(ExitFrameConstants::kCallerSPDisplacement == +2 * kPointerSize);
+ ASSERT(ExitFrameConstants::kCallerPCOffset == +1 * kPointerSize);
+ ASSERT(ExitFrameConstants::kCallerFPOffset == 0 * kPointerSize);
+ push(rbp);
+ movq(rbp, rsp);
+
+ // Reserve room for entry stack pointer and push the debug marker.
+ ASSERT(ExitFrameConstants::kSPOffset == -1 * kPointerSize);
+ push(Immediate(0)); // saved entry sp, patched before call
+ push(Immediate(type == StackFrame::EXIT_DEBUG ? 1 : 0));
+
+ // Save the frame pointer and the context in top.
+ ExternalReference c_entry_fp_address(Top::k_c_entry_fp_address);
+ ExternalReference context_address(Top::k_context_address);
+ movq(rdi, rax); // Backup rax before we use it.
+
+ movq(rax, rbp);
+ store_rax(c_entry_fp_address);
+ movq(rax, rsi);
+ store_rax(context_address);
+
+ // Setup argv in callee-saved register r15. It is reused in LeaveExitFrame,
+ // so it must be retained across the C-call.
+ int offset = StandardFrameConstants::kCallerSPOffset - kPointerSize;
+ lea(r15, Operand(rbp, rdi, kTimesPointerSize, offset));
+
+#ifdef ENABLE_DEBUGGER_SUPPORT
+ // Save the state of all registers to the stack from the memory
+ // location. This is needed to allow nested break points.
+ if (type == StackFrame::EXIT_DEBUG) {
+ // TODO(1243899): This should be symmetric to
+ // CopyRegistersFromStackToMemory() but it isn't! esp is assumed
+ // correct here, but computed for the other call. Very error
+ // prone! FIX THIS. Actually there are deeper problems with
+ // register saving than this asymmetry (see the bug report
+ // associated with this issue).
+ PushRegistersFromMemory(kJSCallerSaved);
+ }
+#endif
+
+ // Reserve space for two arguments: argc and argv
+ subq(rsp, Immediate(2 * kPointerSize));
+
+ // Get the required frame alignment for the OS.
+ static const int kFrameAlignment = OS::ActivationFrameAlignment();
+ if (kFrameAlignment > 0) {
+ ASSERT(IsPowerOf2(kFrameAlignment));
+ movq(kScratchRegister, Immediate(-kFrameAlignment));
+ and_(rsp, kScratchRegister);
+ }
+
+ // Patch the saved entry sp.
+ movq(Operand(rbp, ExitFrameConstants::kSPOffset), rsp);
+}
+
+
+void MacroAssembler::LeaveExitFrame(StackFrame::Type type) {
+ // Registers:
+ // r15 : argv
+#ifdef ENABLE_DEBUGGER_SUPPORT
+ // Restore the memory copy of the registers by digging them out from
+ // the stack. This is needed to allow nested break points.
+ if (type == StackFrame::EXIT_DEBUG) {
+ // It's okay to clobber register ebx below because we don't need
+ // the function pointer after this.
+ const int kCallerSavedSize = kNumJSCallerSaved * kPointerSize;
+ int kOffset = ExitFrameConstants::kDebugMarkOffset - kCallerSavedSize;
+ lea(rbx, Operand(rbp, kOffset));
+ CopyRegistersFromStackToMemory(rbx, rcx, kJSCallerSaved);
+ }
+#endif
+
+ // Get the return address from the stack and restore the frame pointer.
+ movq(rcx, Operand(rbp, 1 * kPointerSize));
+ movq(rbp, Operand(rbp, 0 * kPointerSize));
+
+ // Pop the arguments and the receiver from the caller stack.
+ lea(rsp, Operand(r15, 1 * kPointerSize));
+
+ // Restore current context from top and clear it in debug mode.
+ ExternalReference context_address(Top::k_context_address);
+ movq(kScratchRegister, context_address);
+ movq(rsi, Operand(kScratchRegister, 0));
+#ifdef DEBUG
+ movq(Operand(kScratchRegister, 0), Immediate(0));
+#endif
+
+ // Push the return address to get ready to return.
+ push(rcx);
+
+ // Clear the top frame.
+ ExternalReference c_entry_fp_address(Top::k_c_entry_fp_address);
+ movq(kScratchRegister, c_entry_fp_address);
+ movq(Operand(kScratchRegister, 0), Immediate(0));
+}
+
+
} } // namespace v8::internal