text: // Copyright 2012 the V8 project authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  
  #if V8_TARGET_ARCH_X64
  
  #include "src/api-arguments.h"
  #include "src/base/adapters.h"
  #include "src/code-factory.h"
  #include "src/counters.h"
  #include "src/deoptimizer.h"
  #include "src/frame-constants.h"
  #include "src/frames.h"
  #include "src/macro-assembler-inl.h"
  #include "src/objects-inl.h"
  #include "src/objects/cell.h"
  #include "src/objects/debug-objects.h"
  #include "src/objects/foreign.h"
  #include "src/objects/heap-number.h"
  #include "src/objects/js-generator.h"
  #include "src/objects/smi.h"
  #include "src/register-configuration.h"
  #include "src/wasm/wasm-linkage.h"
  #include "src/wasm/wasm-objects.h"
  
  namespace v8 {
  namespace internal {
  
  #define __ ACCESS_MASM(masm)
  
  void Builtins::Generate_Adaptor(MacroAssembler* masm, Address address,
                                  ExitFrameType exit_frame_type) {
    __ LoadAddress(kJavaScriptCallExtraArg1Register,
                   ExternalReference::Create(address));
    if (exit_frame_type == BUILTIN_EXIT) {
      __ Jump(BUILTIN_CODE(masm->isolate(), AdaptorWithBuiltinExitFrame),
              RelocInfo::CODE_TARGET);
    } else {
      DCHECK(exit_frame_type == EXIT);
      __ Jump(BUILTIN_CODE(masm->isolate(), AdaptorWithExitFrame),
              RelocInfo::CODE_TARGET);
    }
  }
  
  static void GenerateTailCallToReturnedCode(MacroAssembler* masm,
                                             Runtime::FunctionId function_id) {
    // ----------- S t a t e -------------
    //  -- rax : argument count (preserved for callee)
    //  -- rdx : new target (preserved for callee)
    //  -- rdi : target function (preserved for callee)
    // -----------------------------------
    {
      FrameScope scope(masm, StackFrame::INTERNAL);
      // Push the number of arguments to the callee.
      __ SmiTag(rax, rax);
      __ Push(rax);
      // Push a copy of the target function and the new target.
      __ Push(rdi);
      __ Push(rdx);
      // Function is also the parameter to the runtime call.
      __ Push(rdi);
  
      __ CallRuntime(function_id, 1);
      __ movq(rcx, rax);
  
      // Restore target function and new target.
      __ Pop(rdx);
      __ Pop(rdi);
      __ Pop(rax);
      __ SmiUntag(rax, rax);
    }
    static_assert(kJavaScriptCallCodeStartRegister == rcx, "ABI mismatch");
    __ JumpCodeObject(rcx);
  }
  
  namespace {
  
  void Generate_JSBuiltinsConstructStubHelper(MacroAssembler* masm) {
    // ----------- S t a t e -------------
    //  -- rax: number of arguments
    //  -- rdi: constructor function
    //  -- rdx: new target
    //  -- rsi: context
    // -----------------------------------
  
    // Enter a construct frame.
    {
      FrameScope scope(masm, StackFrame::CONSTRUCT);
  
      // Preserve the incoming parameters on the stack.
      __ SmiTag(rcx, rax);
      __ Push(rsi);
      __ Push(rcx);
  
      // The receiver for the builtin/api call.
      __ PushRoot(RootIndex::kTheHoleValue);
  
      // Set up pointer to last argument.
      __ leaq(rbx, Operand(rbp, StandardFrameConstants::kCallerSPOffset));
  
      // Copy arguments and receiver to the expression stack.
      Label loop, entry;
      __ movq(rcx, rax);
      // ----------- S t a t e -------------
      //  --                      rax: number of arguments (untagged)
      //  --                      rdi: constructor function
      //  --                      rdx: new target
      //  --                      rbx: pointer to last argument
      //  --                      rcx: counter
      //  -- sp[0*kSystemPointerSize]: the hole (receiver)
      //  -- sp[1*kSystemPointerSize]: number of arguments (tagged)
      //  -- sp[2*kSystemPointerSize]: context
      // -----------------------------------
      __ jmp(&entry);
      __ bind(&loop);
      __ Push(Operand(rbx, rcx, times_pointer_size, 0));
      __ bind(&entry);
      __ decq(rcx);
      __ j(greater_equal, &loop, Label::kNear);
  
      // Call the function.
      // rax: number of arguments (untagged)
      // rdi: constructor function
      // rdx: new target
      ParameterCount actual(rax);
      __ InvokeFunction(rdi, rdx, actual, CALL_FUNCTION);
  
      // Restore context from the frame.
      __ movq(rsi, Operand(rbp, ConstructFrameConstants::kContextOffset));
      // Restore smi-tagged arguments count from the frame.
      __ movq(rbx, Operand(rbp, ConstructFrameConstants::kLengthOffset));
  
      // Leave construct frame.
    }
  
    // Remove caller arguments from the stack and return.
    __ PopReturnAddressTo(rcx);
    SmiIndex index = masm->SmiToIndex(rbx, rbx, kSystemPointerSizeLog2);
    __ leaq(rsp, Operand(rsp, index.reg, index.scale, 1 * kSystemPointerSize));
    __ PushReturnAddressFrom(rcx);
  
    __ ret(0);
  }
  
  void Generate_StackOverflowCheck(
      MacroAssembler* masm, Register num_args, Register scratch,
      Label* stack_overflow,
      Label::Distance stack_overflow_distance = Label::kFar) {
    // Check the stack for overflow. We are not trying to catch
    // interruptions (e.g. debug break and preemption) here, so the "real stack
    // limit" is checked.
    __ LoadRoot(kScratchRegister, RootIndex::kRealStackLimit);
    __ movq(scratch, rsp);
    // Make scratch the space we have left. The stack might already be overflowed
    // here which will cause scratch to become negative.
    __ subq(scratch, kScratchRegister);
    __ sarq(scratch, Immediate(kSystemPointerSizeLog2));
    // Check if the arguments will overflow the stack.
    __ cmpq(scratch, num_args);
    // Signed comparison.
    __ j(less_equal, stack_overflow, stack_overflow_distance);
  }
  
  }  // namespace
  
  // The construct stub for ES5 constructor functions and ES6 class constructors.
  void Builtins::Generate_JSConstructStubGeneric(MacroAssembler* masm) {
    // ----------- S t a t e -------------
    //  -- rax: number of arguments (untagged)
    //  -- rdi: constructor function
    //  -- rdx: new target
    //  -- rsi: context
    //  -- sp[...]: constructor arguments
    // -----------------------------------
  
    // Enter a construct frame.
    {
      FrameScope scope(masm, StackFrame::CONSTRUCT);
      Label post_instantiation_deopt_entry, not_create_implicit_receiver;
  
      // Preserve the incoming parameters on the stack.
      __ SmiTag(rcx, rax);
      __ Push(rsi);
      __ Push(rcx);
      __ Push(rdi);
      __ PushRoot(RootIndex::kTheHoleValue);
      __ Push(rdx);
  
      // ----------- S t a t e -------------
      //  --         sp[0*kSystemPointerSize]: new target
      //  --         sp[1*kSystemPointerSize]: padding
      //  -- rdi and sp[2*kSystemPointerSize]: constructor function
      //  --         sp[3*kSystemPointerSize]: argument count
      //  --         sp[4*kSystemPointerSize]: context
      // -----------------------------------
  
      Register decompr_scratch_for_debug =
          COMPRESS_POINTERS_BOOL ? kScratchRegister : no_reg;
  
      __ LoadTaggedPointerField(
          rbx, FieldOperand(rdi, JSFunction::kSharedFunctionInfoOffset),
          decompr_scratch_for_debug);
      __ testl(FieldOperand(rbx, SharedFunctionInfo::kFlagsOffset),
               Immediate(SharedFunctionInfo::IsDerivedConstructorBit::kMask));
      __ j(not_zero, &not_create_implicit_receiver, Label::kNear);
  
      // If not derived class constructor: Allocate the new receiver object.
      __ IncrementCounter(masm->isolate()->counters()->constructed_objects(), 1);
      __ Call(BUILTIN_CODE(masm->isolate(), FastNewObject),
              RelocInfo::CODE_TARGET);
      __ jmp(&post_instantiation_deopt_entry, Label::kNear);
  
      // Else: use TheHoleValue as receiver for constructor call
      __ bind(&not_create_implicit_receiver);
      __ LoadRoot(rax, RootIndex::kTheHoleValue);
  
      // ----------- S t a t e -------------
      //  -- rax                          implicit receiver
      //  -- Slot 4 / sp[0*kSystemPointerSize]  new target
      //  -- Slot 3 / sp[1*kSystemPointerSize]  padding
      //  -- Slot 2 / sp[2*kSystemPointerSize]  constructor function
      //  -- Slot 1 / sp[3*kSystemPointerSize]  number of arguments (tagged)
      //  -- Slot 0 / sp[4*kSystemPointerSize]  context
      // -----------------------------------
      // Deoptimizer enters here.
      masm->isolate()->heap()->SetConstructStubCreateDeoptPCOffset(
          masm->pc_offset());
      __ bind(&post_instantiation_deopt_entry);
  
      // Restore new target.
      __ Pop(rdx);
  
      // Push the allocated receiver to the stack. We need two copies
      // because we may have to return the original one and the calling
      // conventions dictate that the called function pops the receiver.
      __ Push(rax);
      __ Push(rax);
  
      // ----------- S t a t e -------------
      //  -- sp[0*kSystemPointerSize]  implicit receiver
      //  -- sp[1*kSystemPointerSize]  implicit receiver
      //  -- sp[2*kSystemPointerSize]  padding
      //  -- sp[3*kSystemPointerSize]  constructor function
      //  -- sp[4*kSystemPointerSize]  number of arguments (tagged)
      //  -- sp[5*kSystemPointerSize]  context
      // -----------------------------------
  
      // Restore constructor function and argument count.
      __ movq(rdi, Operand(rbp, ConstructFrameConstants::kConstructorOffset));
      __ SmiUntag(rax, Operand(rbp, ConstructFrameConstants::kLengthOffset));
  
      // Set up pointer to last argument.
      __ leaq(rbx, Operand(rbp, StandardFrameConstants::kCallerSPOffset));
  
      // Check if we have enough stack space to push all arguments.
      // Argument count in rax. Clobbers rcx.
      Label enough_stack_space, stack_overflow;
      Generate_StackOverflowCheck(masm, rax, rcx, &stack_overflow, Label::kNear);
      __ jmp(&enough_stack_space, Label::kNear);
  
      __ bind(&stack_overflow);
      // Restore context from the frame.
      __ movq(rsi, Operand(rbp, ConstructFrameConstants::kContextOffset));
      __ CallRuntime(Runtime::kThrowStackOverflow);
      // This should be unreachable.
      __ int3();
  
      __ bind(&enough_stack_space);
  
      // Copy arguments and receiver to the expression stack.
      Label loop, entry;
      __ movq(rcx, rax);
      // ----------- S t a t e -------------
      //  --                              rax: number of arguments (untagged)
      //  --                              rdx: new target
      //  --                              rbx: pointer to last argument
      //  --                              rcx: counter (tagged)
      //  --         sp[0*kSystemPointerSize]: implicit receiver
      //  --         sp[1*kSystemPointerSize]: implicit receiver
      //  --         sp[2*kSystemPointerSize]: padding
      //  -- rdi and sp[3*kSystemPointerSize]: constructor function
      //  --         sp[4*kSystemPointerSize]: number of arguments (tagged)
      //  --         sp[5*kSystemPointerSize]: context
      // -----------------------------------
      __ jmp(&entry, Label::kNear);
      __ bind(&loop);
      __ Push(Operand(rbx, rcx, times_pointer_size, 0));
      __ bind(&entry);
      __ decq(rcx);
      __ j(greater_equal, &loop, Label::kNear);
  
      // Call the function.
      ParameterCount actual(rax);
      __ InvokeFunction(rdi, rdx, actual, CALL_FUNCTION);
  
      // ----------- S t a t e -------------
      //  -- rax                 constructor result
      //  -- sp[0*kSystemPointerSize]  implicit receiver
      //  -- sp[1*kSystemPointerSize]  padding
      //  -- sp[2*kSystemPointerSize]  constructor function
      //  -- sp[3*kSystemPointerSize]  number of arguments
      //  -- sp[4*kSystemPointerSize]  context
      // -----------------------------------
  
      // Store offset of return address for deoptimizer.
      masm->isolate()->heap()->SetConstructStubInvokeDeoptPCOffset(
          masm->pc_offset());
  
      // Restore context from the frame.
      __ movq(rsi, Operand(rbp, ConstructFrameConstants::kContextOffset));
  
      // If the result is an object (in the ECMA sense), we should get rid
      // of the receiver and use the result; see ECMA-262 section 13.2.2-7
      // on page 74.
      Label use_receiver, do_throw, leave_frame;
  
      // If the result is undefined, we jump out to using the implicit receiver.
      __ JumpIfRoot(rax, RootIndex::kUndefinedValue, &use_receiver, Label::kNear);
  
      // Otherwise we do a smi check and fall through to check if the return value
      // is a valid receiver.
  
      // If the result is a smi, it is *not* an object in the ECMA sense.
      __ JumpIfSmi(rax, &use_receiver, Label::kNear);
  
      // If the type of the result (stored in its map) is less than
      // FIRST_JS_RECEIVER_TYPE, it is not an object in the ECMA sense.
      STATIC_ASSERT(LAST_JS_RECEIVER_TYPE == LAST_TYPE);
      __ CmpObjectType(rax, FIRST_JS_RECEIVER_TYPE, rcx);
      __ j(above_equal, &leave_frame, Label::kNear);
      __ jmp(&use_receiver, Label::kNear);
  
      __ bind(&do_throw);
      __ CallRuntime(Runtime::kThrowConstructorReturnedNonObject);
  
      // Throw away the result of the constructor invocation and use the
      // on-stack receiver as the result.
      __ bind(&use_receiver);
      __ movq(rax, Operand(rsp, 0 * kSystemPointerSize));
      __ JumpIfRoot(rax, RootIndex::kTheHoleValue, &do_throw, Label::kNear);
  
      __ bind(&leave_frame);
      // Restore the arguments count.
      __ movq(rbx, Operand(rbp, ConstructFrameConstants::kLengthOffset));
      // Leave construct frame.
    }
    // Remove caller arguments from the stack and return.
    __ PopReturnAddressTo(rcx);
    SmiIndex index = masm->SmiToIndex(rbx, rbx, kSystemPointerSizeLog2);
    __ leaq(rsp, Operand(rsp, index.reg, index.scale, 1 * kSystemPointerSize));
    __ PushReturnAddressFrom(rcx);
    __ ret(0);
  }
  
  void Builtins::Generate_JSBuiltinsConstructStub(MacroAssembler* masm) {
    Generate_JSBuiltinsConstructStubHelper(masm);
  }
  
  void Builtins::Generate_ConstructedNonConstructable(MacroAssembler* masm) {
    FrameScope scope(masm, StackFrame::INTERNAL);
    __ Push(rdi);
    __ CallRuntime(Runtime::kThrowConstructedNonConstructable);
  }
  
  namespace {
  
  // Called with the native C calling convention. The corresponding function
  // signature is either:
  //   using JSEntryFunction = GeneratedCode<Address(
  //       Address root_register_value, Address new_target, Address target,
  //       Address receiver, intptr_t argc, Address** argv)>;
  // or
  //   using JSEntryFunction = GeneratedCode<Address(
  //       Address root_register_value, MicrotaskQueue* microtask_queue)>;
  void Generate_JSEntryVariant(MacroAssembler* masm, StackFrame::Type type,
                               Builtins::Name entry_trampoline) {
    Label invoke, handler_entry, exit;
    Label not_outermost_js, not_outermost_js_2;
  
    {  // NOLINT. Scope block confuses linter.
      NoRootArrayScope uninitialized_root_register(masm);
      // Set up frame.
      __ pushq(rbp);
      __ movq(rbp, rsp);
  
      // Push the stack frame type.
      __ Push(Immediate(StackFrame::TypeToMarker(type)));
      // Reserve a slot for the context. It is filled after the root register has
      // been set up.
      __ subq(rsp, Immediate(kSystemPointerSize));
      // Save callee-saved registers (X64/X32/Win64 calling conventions).
      __ pushq(r12);
      __ pushq(r13);
      __ pushq(r14);
      __ pushq(r15);
  #ifdef _WIN64
      __ pushq(rdi);  // Only callee save in Win64 ABI, argument in AMD64 ABI.
      __ pushq(rsi);  // Only callee save in Win64 ABI, argument in AMD64 ABI.
  #endif
      __ pushq(rbx);
  
  #ifdef _WIN64
      // On Win64 XMM6-XMM15 are callee-save.
      __ subq(rsp, Immediate(EntryFrameConstants::kXMMRegistersBlockSize));
      __ movdqu(Operand(rsp, EntryFrameConstants::kXMMRegisterSize * 0), xmm6);
      __ movdqu(Operand(rsp, EntryFrameConstants::kXMMRegisterSize * 1), xmm7);
      __ movdqu(Operand(rsp, EntryFrameConstants::kXMMRegisterSize * 2), xmm8);
      __ movdqu(Operand(rsp, EntryFrameConstants::kXMMRegisterSize * 3), xmm9);
      __ movdqu(Operand(rsp, EntryFrameConstants::kXMMRegisterSize * 4), xmm10);
      __ movdqu(Operand(rsp, EntryFrameConstants::kXMMRegisterSize * 5), xmm11);
      __ movdqu(Operand(rsp, EntryFrameConstants::kXMMRegisterSize * 6), xmm12);
      __ movdqu(Operand(rsp, EntryFrameConstants::kXMMRegisterSize * 7), xmm13);
      __ movdqu(Operand(rsp, EntryFrameConstants::kXMMRegisterSize * 8), xmm14);
      __ movdqu(Operand(rsp, EntryFrameConstants::kXMMRegisterSize * 9), xmm15);
      STATIC_ASSERT(EntryFrameConstants::kCalleeSaveXMMRegisters == 10);
      STATIC_ASSERT(EntryFrameConstants::kXMMRegistersBlockSize ==
                    EntryFrameConstants::kXMMRegisterSize *
                        EntryFrameConstants::kCalleeSaveXMMRegisters);
  #endif
  
      // Initialize the root register.
      // C calling convention. The first argument is passed in arg_reg_1.
      __ movq(kRootRegister, arg_reg_1);
    }
  
    // Save copies of the top frame descriptor on the stack.
    ExternalReference c_entry_fp = ExternalReference::Create(
        IsolateAddressId::kCEntryFPAddress, masm->isolate());
    {
      Operand c_entry_fp_operand = masm->ExternalReferenceAsOperand(c_entry_fp);
      __ Push(c_entry_fp_operand);
    }
  
    // Store the context address in the previously-reserved slot.
    ExternalReference context_address = ExternalReference::Create(
        IsolateAddressId::kContextAddress, masm->isolate());
    __ Load(kScratchRegister, context_address);
    static constexpr int kOffsetToContextSlot = -2 * kSystemPointerSize;
    __ movq(Operand(rbp, kOffsetToContextSlot), kScratchRegister);
  
    // If this is the outermost JS call, set js_entry_sp value.
    ExternalReference js_entry_sp = ExternalReference::Create(
        IsolateAddressId::kJSEntrySPAddress, masm->isolate());
    __ Load(rax, js_entry_sp);
    __ testq(rax, rax);
    __ j(not_zero, &not_outermost_js);
    __ Push(Immediate(StackFrame::OUTERMOST_JSENTRY_FRAME));
    __ movq(rax, rbp);
    __ Store(js_entry_sp, rax);
    Label cont;
    __ jmp(&cont);
    __ bind(&not_outermost_js);
    __ Push(Immediate(StackFrame::INNER_JSENTRY_FRAME));
    __ bind(&cont);
  
    // Jump to a faked try block that does the invoke, with a faked catch
    // block that sets the pending exception.
    __ jmp(&invoke);
    __ bind(&handler_entry);
  
    // Store the current pc as the handler offset. It's used later to create the
    // handler table.
    masm->isolate()->builtins()->SetJSEntryHandlerOffset(handler_entry.pos());
  
    // Caught exception: Store result (exception) in the pending exception
    // field in the JSEnv and return a failure sentinel.
    ExternalReference pending_exception = ExternalReference::Create(
        IsolateAddressId::kPendingExceptionAddress, masm->isolate());
    __ Store(pending_exception, rax);
    __ LoadRoot(rax, RootIndex::kException);
    __ jmp(&exit);
  
    // Invoke: Link this frame into the handler chain.
    __ bind(&invoke);
    __ PushStackHandler();
  
    // Invoke the function by calling through JS entry trampoline builtin and
    // pop the faked function when we return.
    Handle<Code> trampoline_code =
        masm->isolate()->builtins()->builtin_handle(entry_trampoline);
    __ Call(trampoline_code, RelocInfo::CODE_TARGET);
  
    // Unlink this frame from the handler chain.
    __ PopStackHandler();
  
    __ bind(&exit);
    // Check if the current stack frame is marked as the outermost JS frame.
    __ Pop(rbx);
    __ cmpq(rbx, Immediate(StackFrame::OUTERMOST_JSENTRY_FRAME));
    __ j(not_equal, &not_outermost_js_2);
    __ Move(kScratchRegister, js_entry_sp);
    __ movq(Operand(kScratchRegister, 0), Immediate(0));
    __ bind(&not_outermost_js_2);
  
    // Restore the top frame descriptor from the stack.
    {
      Operand c_entry_fp_operand = masm->ExternalReferenceAsOperand(c_entry_fp);
      __ Pop(c_entry_fp_operand);
    }
  
    // Restore callee-saved registers (X64 conventions).
  #ifdef _WIN64
    // On Win64 XMM6-XMM15 are callee-save
    __ movdqu(xmm6, Operand(rsp, EntryFrameConstants::kXMMRegisterSize * 0));
    __ movdqu(xmm7, Operand(rsp, EntryFrameConstants::kXMMRegisterSize * 1));
    __ movdqu(xmm8, Operand(rsp, EntryFrameConstants::kXMMRegisterSize * 2));
    __ movdqu(xmm9, Operand(rsp, EntryFrameConstants::kXMMRegisterSize * 3));
    __ movdqu(xmm10, Operand(rsp, EntryFrameConstants::kXMMRegisterSize * 4));
    __ movdqu(xmm11, Operand(rsp, EntryFrameConstants::kXMMRegisterSize * 5));
    __ movdqu(xmm12, Operand(rsp, EntryFrameConstants::kXMMRegisterSize * 6));
    __ movdqu(xmm13, Operand(rsp, EntryFrameConstants::kXMMRegisterSize * 7));
    __ movdqu(xmm14, Operand(rsp, EntryFrameConstants::kXMMRegisterSize * 8));
    __ movdqu(xmm15, Operand(rsp, EntryFrameConstants::kXMMRegisterSize * 9));
    __ addq(rsp, Immediate(EntryFrameConstants::kXMMRegistersBlockSize));
  #endif
  
    __ popq(rbx);
  #ifdef _WIN64
    // Callee save on in Win64 ABI, arguments/volatile in AMD64 ABI.
    __ popq(rsi);
    __ popq(rdi);
  #endif
    __ popq(r15);
    __ popq(r14);
    __ popq(r13);
    __ popq(r12);
    __ addq(rsp, Immediate(2 * kSystemPointerSize));  // remove markers
  
    // Restore frame pointer and return.
    __ popq(rbp);
    __ ret(0);
  }
  
  }  // namespace
  
  void Builtins::Generate_JSEntry(MacroAssembler* masm) {
    Generate_JSEntryVariant(masm, StackFrame::ENTRY,
                            Builtins::kJSEntryTrampoline);
  }
  
  void Builtins::Generate_JSConstructEntry(MacroAssembler* masm) {
    Generate_JSEntryVariant(masm, StackFrame::CONSTRUCT_ENTRY,
                            Builtins::kJSConstructEntryTrampoline);
  }
  
  void Builtins::Generate_JSRunMicrotasksEntry(MacroAssembler* masm) {
    Generate_JSEntryVariant(masm, StackFrame::ENTRY,
                            Builtins::kRunMicrotasksTrampoline);
  }
  
  static void Generate_JSEntryTrampolineHelper(MacroAssembler* masm,
                                               bool is_construct) {
    // Expects six C++ function parameters.
    // - Address root_register_value
    // - Address new_target (tagged Object pointer)
    // - Address function (tagged JSFunction pointer)
    // - Address receiver (tagged Object pointer)
    // - intptr_t argc
    // - Address** argv (pointer to array of tagged Object pointers)
    // (see Handle::Invoke in execution.cc).
  
    // Open a C++ scope for the FrameScope.
    {
      // Platform specific argument handling. After this, the stack contains
      // an internal frame and the pushed function and receiver, and
      // register rax and rbx holds the argument count and argument array,
      // while rdi holds the function pointer, rsi the context, and rdx the
      // new.target.
  
      // MSVC parameters in:
      // rcx        : root_register_value
      // rdx        : new_target
      // r8         : function
      // r9         : receiver
      // [rsp+0x20] : argc
      // [rsp+0x28] : argv
      //
      // GCC parameters in:
      // rdi : root_register_value
      // rsi : new_target
      // rdx : function
      // rcx : receiver
      // r8  : argc
      // r9  : argv
  
      __ movq(rdi, arg_reg_3);
      __ Move(rdx, arg_reg_2);
      // rdi : function
      // rdx : new_target
  
      // Clear the context before we push it when entering the internal frame.
      __ Set(rsi, 0);
  
      // Enter an internal frame.
      FrameScope scope(masm, StackFrame::INTERNAL);
  
      // Setup the context (we need to use the caller context from the isolate).
      ExternalReference context_address = ExternalReference::Create(
          IsolateAddressId::kContextAddress, masm->isolate());
      __ movq(rsi, masm->ExternalReferenceAsOperand(context_address));
  
      // Push the function and the receiver onto the stack.
      __ Push(rdi);
      __ Push(arg_reg_4);
  
  #ifdef _WIN64
      // Load the previous frame pointer to access C arguments on stack
      __ movq(kScratchRegister, Operand(rbp, 0));
      // Load the number of arguments and setup pointer to the arguments.
      __ movq(rax, Operand(kScratchRegister, EntryFrameConstants::kArgcOffset));
      __ movq(rbx, Operand(kScratchRegister, EntryFrameConstants::kArgvOffset));
  #else   // _WIN64
      // Load the number of arguments and setup pointer to the arguments.
      __ movq(rax, r8);
      __ movq(rbx, r9);
  #endif  // _WIN64
  
      // Current stack contents:
      // [rsp + 2 * kSystemPointerSize ... ] : Internal frame
      // [rsp + kSystemPointerSize]          : function
      // [rsp]                         : receiver
      // Current register contents:
      // rax : argc
      // rbx : argv
      // rsi : context
      // rdi : function
      // rdx : new.target
  
      // Check if we have enough stack space to push all arguments.
      // Argument count in rax. Clobbers rcx.
      Label enough_stack_space, stack_overflow;
      Generate_StackOverflowCheck(masm, rax, rcx, &stack_overflow, Label::kNear);
      __ jmp(&enough_stack_space, Label::kNear);
  
      __ bind(&stack_overflow);
      __ CallRuntime(Runtime::kThrowStackOverflow);
      // This should be unreachable.
      __ int3();
  
      __ bind(&enough_stack_space);
  
      // Copy arguments to the stack in a loop.
      // Register rbx points to array of pointers to handle locations.
      // Push the values of these handles.
      Label loop, entry;
      __ Set(rcx, 0);  // Set loop variable to 0.
      __ jmp(&entry, Label::kNear);
      __ bind(&loop);
      __ movq(kScratchRegister, Operand(rbx, rcx, times_pointer_size, 0));
      __ Push(Operand(kScratchRegister, 0));  // dereference handle
      __ addq(rcx, Immediate(1));
      __ bind(&entry);
      __ cmpq(rcx, rax);
      __ j(not_equal, &loop, Label::kNear);
  
      // Invoke the builtin code.
      Handle<Code> builtin = is_construct
                                 ? BUILTIN_CODE(masm->isolate(), Construct)
                                 : masm->isolate()->builtins()->Call();
      __ Call(builtin, RelocInfo::CODE_TARGET);
  
      // Exit the internal frame. Notice that this also removes the empty
      // context and the function left on the stack by the code
      // invocation.
    }
  
    __ ret(0);
  }
  
  void Builtins::Generate_JSEntryTrampoline(MacroAssembler* masm) {
    Generate_JSEntryTrampolineHelper(masm, false);
  }
  
  void Builtins::Generate_JSConstructEntryTrampoline(MacroAssembler* masm) {
    Generate_JSEntryTrampolineHelper(masm, true);
  }
  
  void Builtins::Generate_RunMicrotasksTrampoline(MacroAssembler* masm) {
    // arg_reg_2: microtask_queue
    __ movq(RunMicrotasksDescriptor::MicrotaskQueueRegister(), arg_reg_2);
    __ Jump(BUILTIN_CODE(masm->isolate(), RunMicrotasks), RelocInfo::CODE_TARGET);
  }
  
  static void GetSharedFunctionInfoBytecode(MacroAssembler* masm,
                                            Register sfi_data,
                                            Register scratch1) {
    Label done;
  
    __ CmpObjectType(sfi_data, INTERPRETER_DATA_TYPE, scratch1);
    __ j(not_equal, &done, Label::kNear);
    Register decompr_scratch_for_debug =
        COMPRESS_POINTERS_BOOL ? scratch1 : no_reg;
  
    __ LoadTaggedPointerField(
        sfi_data, FieldOperand(sfi_data, InterpreterData::kBytecodeArrayOffset),
        decompr_scratch_for_debug);
  
    __ bind(&done);
  }
  
  // static
  void Builtins::Generate_ResumeGeneratorTrampoline(MacroAssembler* masm) {
    // ----------- S t a t e -------------
    //  -- rax    : the value to pass to the generator
    //  -- rdx    : the JSGeneratorObject to resume
    //  -- rsp[0] : return address
    // -----------------------------------
    __ AssertGeneratorObject(rdx);
  
    // Store input value into generator object.
    __ StoreTaggedField(
        FieldOperand(rdx, JSGeneratorObject::kInputOrDebugPosOffset), rax);
    __ RecordWriteField(rdx, JSGeneratorObject::kInputOrDebugPosOffset, rax, rcx,
                        kDontSaveFPRegs);
  
    Register decompr_scratch1 = COMPRESS_POINTERS_BOOL ? r11 : no_reg;
    Register decompr_scratch2 = COMPRESS_POINTERS_BOOL ? r12 : no_reg;
    Register decompr_scratch_for_debug =
        COMPRESS_POINTERS_BOOL ? kScratchRegister : no_reg;
  
    // Load suspended function and context.
    __ LoadTaggedPointerField(
        rdi, FieldOperand(rdx, JSGeneratorObject::kFunctionOffset),
        decompr_scratch_for_debug);
    __ LoadTaggedPointerField(rsi, FieldOperand(rdi, JSFunction::kContextOffset),
                              decompr_scratch_for_debug);
  
    // Flood function if we are stepping.
    Label prepare_step_in_if_stepping, prepare_step_in_suspended_generator;
    Label stepping_prepared;
    ExternalReference debug_hook =
        ExternalReference::debug_hook_on_function_call_address(masm->isolate());
    Operand debug_hook_operand = masm->ExternalReferenceAsOperand(debug_hook);
    __ cmpb(debug_hook_operand, Immediate(0));
    __ j(not_equal, &prepare_step_in_if_stepping);
  
    // Flood function if we need to continue stepping in the suspended generator.
    ExternalReference debug_suspended_generator =
        ExternalReference::debug_suspended_generator_address(masm->isolate());
    Operand debug_suspended_generator_operand =
        masm->ExternalReferenceAsOperand(debug_suspended_generator);
    __ cmpq(rdx, debug_suspended_generator_operand);
    __ j(equal, &prepare_step_in_suspended_generator);
    __ bind(&stepping_prepared);
  
    // Check the stack for overflow. We are not trying to catch interruptions
    // (i.e. debug break and preemption) here, so check the "real stack limit".
    Label stack_overflow;
    __ CompareRoot(rsp, RootIndex::kRealStackLimit);
    __ j(below, &stack_overflow);
  
    // Pop return address.
    __ PopReturnAddressTo(rax);
  
    // Push receiver.
    __ PushTaggedPointerField(
        FieldOperand(rdx, JSGeneratorObject::kReceiverOffset), decompr_scratch1,
        decompr_scratch_for_debug);
  
    // ----------- S t a t e -------------
    //  -- rax    : return address
    //  -- rdx    : the JSGeneratorObject to resume
    //  -- rdi    : generator function
    //  -- rsi    : generator context
    //  -- rsp[0] : generator receiver
    // -----------------------------------
  
    // Copy the function arguments from the generator object's register file.
    __ LoadTaggedPointerField(
        rcx, FieldOperand(rdi, JSFunction::kSharedFunctionInfoOffset),
        decompr_scratch_for_debug);
    __ movzxwq(
        rcx, FieldOperand(rcx, SharedFunctionInfo::kFormalParameterCountOffset));
  
    __ LoadTaggedPointerField(
        rbx, FieldOperand(rdx, JSGeneratorObject::kParametersAndRegistersOffset),
        decompr_scratch_for_debug);
  
    {
      Label done_loop, loop;
      __ Set(r9, 0);
  
      __ bind(&loop);
      __ cmpl(r9, rcx);
      __ j(greater_equal, &done_loop, Label::kNear);
      __ PushTaggedAnyField(
          FieldOperand(rbx, r9, times_tagged_size, FixedArray::kHeaderSize),
          decompr_scratch1, decompr_scratch2, decompr_scratch_for_debug);
      __ addl(r9, Immediate(1));
      __ jmp(&loop);
  
      __ bind(&done_loop);
    }
  
    // Underlying function needs to have bytecode available.
    if (FLAG_debug_code) {
      __ LoadTaggedPointerField(
          rcx, FieldOperand(rdi, JSFunction::kSharedFunctionInfoOffset),
          decompr_scratch_for_debug);
      __ LoadTaggedPointerField(
          rcx, FieldOperand(rcx, SharedFunctionInfo::kFunctionDataOffset),
          decompr_scratch_for_debug);
      GetSharedFunctionInfoBytecode(masm, rcx, kScratchRegister);
      __ CmpObjectType(rcx, BYTECODE_ARRAY_TYPE, rcx);
      __ Assert(equal, AbortReason::kMissingBytecodeArray);
    }
  
    // Resume (Ignition/TurboFan) generator object.
    {
      __ PushReturnAddressFrom(rax);
      __ LoadTaggedPointerField(
          rax, FieldOperand(rdi, JSFunction::kSharedFunctionInfoOffset),
          decompr_scratch_for_debug);
      __ movzxwq(rax, FieldOperand(
                          rax, SharedFunctionInfo::kFormalParameterCountOffset));
      // We abuse new.target both to indicate that this is a resume call and to
      // pass in the generator object.  In ordinary calls, new.target is always
      // undefined because generator functions are non-constructable.
      static_assert(kJavaScriptCallCodeStartRegister == rcx, "ABI mismatch");
      __ LoadTaggedPointerField(rcx, FieldOperand(rdi, JSFunction::kCodeOffset),
                                decompr_scratch_for_debug);
      __ JumpCodeObject(rcx);
    }
  
    __ bind(&prepare_step_in_if_stepping);
    {
      FrameScope scope(masm, StackFrame::INTERNAL);
      __ Push(rdx);
      __ Push(rdi);
      // Push hole as receiver since we do not use it for stepping.
      __ PushRoot(RootIndex::kTheHoleValue);
      __ CallRuntime(Runtime::kDebugOnFunctionCall);
      __ Pop(rdx);
      __ LoadTaggedPointerField(
          rdi, FieldOperand(rdx, JSGeneratorObject::kFunctionOffset),
          decompr_scratch_for_debug);
    }
    __ jmp(&stepping_prepared);
  
    __ bind(&prepare_step_in_suspended_generator);
    {
      FrameScope scope(masm, StackFrame::INTERNAL);
      __ Push(rdx);
      __ CallRuntime(Runtime::kDebugPrepareStepInSuspendedGenerator);
      __ Pop(rdx);
      __ LoadTaggedPointerField(
          rdi, FieldOperand(rdx, JSGeneratorObject::kFunctionOffset),
          decompr_scratch_for_debug);
    }
    __ jmp(&stepping_prepared);
  
    __ bind(&stack_overflow);
    {
      FrameScope scope(masm, StackFrame::INTERNAL);
      __ CallRuntime(Runtime::kThrowStackOverflow);
      __ int3();  // This should be unreachable.
    }
  }
  
  // TODO(juliana): if we remove the code below then we don't need all
  // the parameters.
  static void ReplaceClosureCodeWithOptimizedCode(
      MacroAssembler* masm, Register optimized_code, Register closure,
      Register scratch1, Register scratch2, Register scratch3) {
  
    // Store the optimized code in the closure.
    __ StoreTaggedField(FieldOperand(closure, JSFunction::kCodeOffset),
                        optimized_code);
    __ movq(scratch1, optimized_code);  // Write barrier clobbers scratch1 below.
    __ RecordWriteField(closure, JSFunction::kCodeOffset, scratch1, scratch2,
                        kDontSaveFPRegs, OMIT_REMEMBERED_SET, OMIT_SMI_CHECK);
  }
  
  static void LeaveInterpreterFrame(MacroAssembler* masm, Register scratch1,
                                    Register scratch2) {
    Register args_count = scratch1;
    Register return_pc = scratch2;
  
    // Get the arguments + receiver count.
    __ movq(args_count,
            Operand(rbp, InterpreterFrameConstants::kBytecodeArrayFromFp));
    __ movl(args_count,
            FieldOperand(args_count, BytecodeArray::kParameterSizeOffset));
  
    // Leave the frame (also dropping the register file).
    __ leave();
  
    // Drop receiver + arguments.
    __ PopReturnAddressTo(return_pc);
    __ addq(rsp, args_count);
    __ PushReturnAddressFrom(return_pc);
  }
  
  // Tail-call |function_id| if |smi_entry| == |marker|
  static void TailCallRuntimeIfMarkerEquals(MacroAssembler* masm,
                                            Register smi_entry,
                                            OptimizationMarker marker,
                                            Runtime::FunctionId function_id) {
    Label no_match;
    __ SmiCompare(smi_entry, Smi::FromEnum(marker));
    __ j(not_equal, &no_match);
    GenerateTailCallToReturnedCode(masm, function_id);
    __ bind(&no_match);
  }
  
  static void MaybeTailCallOptimizedCodeSlot(MacroAssembler* masm,
                                             Register feedback_vector,
                                             Register scratch1, Register scratch2,
                                             Register scratch3) {
    // ----------- S t a t e -------------
    //  -- rax : argument count (preserved for callee if needed, and caller)
    //  -- rdx : new target (preserved for callee if needed, and caller)
    //  -- rdi : target function (preserved for callee if needed, and caller)
    //  -- feedback vector (preserved for caller if needed)
    // -----------------------------------
    DCHECK(!AreAliased(feedback_vector, rax, rdx, rdi, scratch1, scratch2,
                       scratch3));
  
    Label optimized_code_slot_is_weak_ref, fallthrough;
  
    Register closure = rdi;
    Register optimized_code_entry = scratch1;
    Register decompr_scratch = COMPRESS_POINTERS_BOOL ? scratch2 : no_reg;
    Register decompr_scratch_for_debug =
        COMPRESS_POINTERS_BOOL ? scratch3 : no_reg;
  
    __ LoadAnyTaggedField(
        optimized_code_entry,
        FieldOperand(feedback_vector, FeedbackVector::kOptimizedCodeOffset),
        decompr_scratch, decompr_scratch_for_debug);
  
    // Check if the code entry is a Smi. If yes, we interpret it as an
    // optimisation marker. Otherwise, interpret it as a weak reference to a code
    // object.
    __ JumpIfNotSmi(optimized_code_entry, &optimized_code_slot_is_weak_ref);
  
    {
      // Optimized code slot is a Smi optimization marker.
  
      // Fall through if no optimization trigger.
      __ SmiCompare(optimized_code_entry,
                    Smi::FromEnum(OptimizationMarker::kNone));
      __ j(equal, &fallthrough);
  
      // TODO(v8:8394): The logging of first execution will break if
      // feedback vectors are not allocated. We need to find a different way of
      // logging these events if required.
      TailCallRuntimeIfMarkerEquals(masm, optimized_code_entry,
                                    OptimizationMarker::kLogFirstExecution,
                                    Runtime::kFunctionFirstExecution);
      TailCallRuntimeIfMarkerEquals(masm, optimized_code_entry,
                                    OptimizationMarker::kCompileOptimized,
                                    Runtime::kCompileOptimized_NotConcurrent);
      TailCallRuntimeIfMarkerEquals(
          masm, optimized_code_entry,
          OptimizationMarker::kCompileOptimizedConcurrent,
          Runtime::kCompileOptimized_Concurrent);
  
      {
        // Otherwise, the marker is InOptimizationQueue, so fall through hoping
        // that an interrupt will eventually update the slot with optimized code.
        if (FLAG_debug_code) {
          __ SmiCompare(optimized_code_entry,
                        Smi::FromEnum(OptimizationMarker::kInOptimizationQueue));
          __ Assert(equal, AbortReason::kExpectedOptimizationSentinel);
        }
        __ jmp(&fallthrough);
      }
    }
  
    {
      // Optimized code slot is a weak reference.
      __ bind(&optimized_code_slot_is_weak_ref);
  
      __ LoadWeakValue(optimized_code_entry, &fallthrough);
  
      // Check if the optimized code is marked for deopt. If it is, call the
      // runtime to clear it.
      Label found_deoptimized_code;
      __ LoadTaggedPointerField(
          scratch2,
          FieldOperand(optimized_code_entry, Code::kCodeDataContainerOffset),
          decompr_scratch_for_debug);
      __ testl(
          FieldOperand(scratch2, CodeDataContainer::kKindSpecificFlagsOffset),
          Immediate(1 << Code::kMarkedForDeoptimizationBit));
      __ j(not_zero, &found_deoptimized_code);
  
      // Optimized code is good, get it into the closure and link the closure into
      // the optimized functions list, then tail call the optimized code.
      // The feedback vector is no longer used, so re-use it as a scratch
      // register.
      ReplaceClosureCodeWithOptimizedCode(masm, optimized_code_entry, closure,
                                          scratch2, scratch3, feedback_vector);
      static_assert(kJavaScriptCallCodeStartRegister == rcx, "ABI mismatch");
      __ Move(rcx, optimized_code_entry);
      __ JumpCodeObject(rcx);
  
      // Optimized code slot contains deoptimized code, evict it and re-enter the
      // closure's code.
      __ bind(&found_deoptimized_code);
      GenerateTailCallToReturnedCode(masm, Runtime::kEvictOptimizedCodeSlot);
    }
  
    // Fall-through if the optimized code cell is clear and there is no
    // optimization marker.
    __ bind(&fallthrough);
  }
  
  // Advance the current bytecode offset. This simulates what all bytecode
  // handlers do upon completion of the underlying operation. Will bail out to a
  // label if the bytecode (without prefix) is a return bytecode.
  static void AdvanceBytecodeOffsetOrReturn(MacroAssembler* masm,
                                            Register bytecode_array,
                                            Register bytecode_offset,
                                            Register bytecode, Register scratch1,
                                            Label* if_return) {
    Register bytecode_size_table = scratch1;
    DCHECK(!AreAliased(bytecode_array, bytecode_offset, bytecode_size_table,
                       bytecode));
  
    __ Move(bytecode_size_table,
            ExternalReference::bytecode_size_table_address());
  
    // Check if the bytecode is a Wide or ExtraWide prefix bytecode.
    Label process_bytecode, extra_wide;
    STATIC_ASSERT(0 == static_cast<int>(interpreter::Bytecode::kWide));
    STATIC_ASSERT(1 == static_cast<int>(interpreter::Bytecode::kExtraWide));
    STATIC_ASSERT(2 == static_cast<int>(interpreter::Bytecode::kDebugBreakWide));
    STATIC_ASSERT(3 ==
                  static_cast<int>(interpreter::Bytecode::kDebugBreakExtraWide));
    __ cmpb(bytecode, Immediate(0x3));
    __ j(above, &process_bytecode, Label::kNear);
    __ testb(bytecode, Immediate(0x1));
    __ j(not_equal, &extra_wide, Label::kNear);
  
    // Load the next bytecode and update table to the wide scaled table.
    __ incl(bytecode_offset);
    __ movzxbq(bytecode, Operand(bytecode_array, bytecode_offset, times_1, 0));
    __ addq(bytecode_size_table,
            Immediate(kIntSize * interpreter::Bytecodes::kBytecodeCount));
    __ jmp(&process_bytecode, Label::kNear);
  
    __ bind(&extra_wide);
    // Load the next bytecode and update table to the extra wide scaled table.
    __ incl(bytecode_offset);
    __ movzxbq(bytecode, Operand(bytecode_array, bytecode_offset, times_1, 0));
    __ addq(bytecode_size_table,
            Immediate(2 * kIntSize * interpreter::Bytecodes::kBytecodeCount));
  
    __ bind(&process_bytecode);
  
  // Bailout to the return label if this is a return bytecode.
  #define JUMP_IF_EQUAL(NAME)                                             \
    __ cmpb(bytecode,                                                     \
            Immediate(static_cast<int>(interpreter::Bytecode::k##NAME))); \
    __ j(equal, if_return, Label::kFar);
    RETURN_BYTECODE_LIST(JUMP_IF_EQUAL)
  #undef JUMP_IF_EQUAL
  
    // Otherwise, load the size of the current bytecode and advance the offset.
    __ addl(bytecode_offset, Operand(bytecode_size_table, bytecode, times_4, 0));
  }
  
  // Generate code for entering a JS function with the interpreter.
  // On entry to the function the receiver and arguments have been pushed on the
  // stack left to right.  The actual argument count matches the formal parameter
  // count expected by the function.
  //
  // The live registers are:
  //   o rdi: the JS function object being called
  //   o rdx: the incoming new target or generator object
  //   o rsi: our context
  //   o rbp: the caller's frame pointer
  //   o rsp: stack pointer (pointing to return address)
  //
  // The function builds an interpreter frame.  See InterpreterFrameConstants in
  // frames.h for its layout.
  void Builtins::Generate_InterpreterEntryTrampoline(MacroAssembler* masm) {
    Register closure = rdi;
    Register feedback_vector = rbx;
    Register decompr_scratch_for_debug =
        COMPRESS_POINTERS_BOOL ? kScratchRegister : no_reg;
  
    // Get the bytecode array from the function object and load it into
    // kInterpreterBytecodeArrayRegister.
    __ LoadTaggedPointerField(
        rax, FieldOperand(closure, JSFunction::kSharedFunctionInfoOffset),
        decompr_scratch_for_debug);
    __ LoadTaggedPointerField(
        kInterpreterBytecodeArrayRegister,
        FieldOperand(rax, SharedFunctionInfo::kFunctionDataOffset),
        decompr_scratch_for_debug);
    GetSharedFunctionInfoBytecode(masm, kInterpreterBytecodeArrayRegister,
                                  kScratchRegister);
  
    // The bytecode array could have been flushed from the shared function info,
    // if so, call into CompileLazy.
    Label compile_lazy;
    __ CmpObjectType(kInterpreterBytecodeArrayRegister, BYTECODE_ARRAY_TYPE, rax);
    __ j(not_equal, &compile_lazy);
  
    // Load the feedback vector from the closure.
    __ LoadTaggedPointerField(
        feedback_vector, FieldOperand(closure, JSFunction::kFeedbackCellOffset),
        decompr_scratch_for_debug);
    __ LoadTaggedPointerField(feedback_vector,
                              FieldOperand(feedback_vector, Cell::kValueOffset),
                              decompr_scratch_for_debug);
  
    Label push_stack_frame;
    // Check if feedback vector is valid. If valid, check for optimized code
    // and update invocation count. Otherwise, setup the stack frame.
    __ JumpIfRoot(feedback_vector, RootIndex::kUndefinedValue, &push_stack_frame);
  
    // Read off the optimized code slot in the feedback vector, and if there
    // is optimized code or an optimization marker, call that instead.
    MaybeTailCallOptimizedCodeSlot(masm, feedback_vector, rcx, r11, r15);
  
    // Increment invocation count for the function.
    __ incl(
        FieldOperand(feedback_vector, FeedbackVector::kInvocationCountOffset));
  
    // Open a frame scope to indicate that there is a frame on the stack.  The
    // MANUAL indicates that the scope shouldn't actually generate code to set up
    // the frame (that is done below).
    __ bind(&push_stack_frame);
    FrameScope frame_scope(masm, StackFrame::MANUAL);
    __ pushq(rbp);  // Caller's frame pointer.
    __ movq(rbp, rsp);
    __ Push(rsi);  // Callee's context.
    __ Push(rdi);  // Callee's JS function.
  
    // Reset code age.
    __ movb(FieldOperand(kInterpreterBytecodeArrayRegister,
                         BytecodeArray::kBytecodeAgeOffset),
            Immediate(BytecodeArray::kNoAgeBytecodeAge));
  
    // Load initial bytecode offset.
    __ movq(kInterpreterBytecodeOffsetRegister,
            Immediate(BytecodeArray::kHeaderSize - kHeapObjectTag));
  
    // Push bytecode array and Smi tagged bytecode offset.
    __ Push(kInterpreterBytecodeArrayRegister);
    __ SmiTag(rcx, kInterpreterBytecodeOffsetRegister);
    __ Push(rcx);
  
    // Allocate the local and temporary register file on the stack.
    {
      // Load frame size from the BytecodeArray object.
      __ movl(rcx, FieldOperand(kInterpreterBytecodeArrayRegister,
                                BytecodeArray::kFrameSizeOffset));
  
      // Do a stack check to ensure we don't go over the limit.
      Label ok;
      __ movq(rax, rsp);
      __ subq(rax, rcx);
      __ CompareRoot(rax, RootIndex::kRealStackLimit);
      __ j(above_equal, &ok, Label::kNear);
      __ CallRuntime(Runtime::kThrowStackOverflow);
      __ bind(&ok);
  
      // If ok, push undefined as the initial value for all register file entries.
      Label loop_header;
      Label loop_check;
      __ LoadRoot(rax, RootIndex::kUndefinedValue);
      __ j(always, &loop_check, Label::kNear);
      __ bind(&loop_header);
      // TODO(rmcilroy): Consider doing more than one push per loop iteration.
      __ Push(rax);
      // Continue loop if not done.
      __ bind(&loop_check);
      __ subq(rcx, Immediate(kSystemPointerSize));
      __ j(greater_equal, &loop_header, Label::kNear);
    }
  
    // If the bytecode array has a valid incoming new target or generator object
    // register, initialize it with incoming value which was passed in rdx.
    Label no_incoming_new_target_or_generator_register;
    __ movsxlq(
        rax,
        FieldOperand(kInterpreterBytecodeArrayRegister,
                     BytecodeArray::kIncomingNewTargetOrGeneratorRegisterOffset));
    __ testl(rax, rax);
    __ j(zero, &no_incoming_new_target_or_generator_register, Label::kNear);
    __ movq(Operand(rbp, rax, times_pointer_size, 0), rdx);
    __ bind(&no_incoming_new_target_or_generator_register);
  
    // Load accumulator with undefined.
    __ LoadRoot(kInterpreterAccumulatorRegister, RootIndex::kUndefinedValue);
  
    // Load the dispatch table into a register and dispatch to the bytecode
    // handler at the current bytecode offset.
    Label do_dispatch;
    __ bind(&do_dispatch);
    __ Move(
        kInterpreterDispatchTableRegister,
        ExternalReference::interpreter_dispatch_table_address(masm->isolate()));
    __ movzxbq(r11, Operand(kInterpreterBytecodeArrayRegister,
                            kInterpreterBytecodeOffsetRegister, times_1, 0));
    __ movq(
        kJavaScriptCallCodeStartRegister,
        Operand(kInterpreterDispatchTableRegister, r11, times_pointer_size, 0));
    __ call(kJavaScriptCallCodeStartRegister);
    masm->isolate()->heap()->SetInterpreterEntryReturnPCOffset(masm->pc_offset());
  
    // Any returns to the entry trampoline are either due to the return bytecode
    // or the interpreter tail calling a builtin and then a dispatch.
  
    // Get bytecode array and bytecode offset from the stack frame.
    __ movq(kInterpreterBytecodeArrayRegister,
            Operand(rbp, InterpreterFrameConstants::kBytecodeArrayFromFp));
    __ movq(kInterpreterBytecodeOffsetRegister,
            Operand(rbp, InterpreterFrameConstants::kBytecodeOffsetFromFp));
    __ SmiUntag(kInterpreterBytecodeOffsetRegister,
                kInterpreterBytecodeOffsetRegister);
  
    // Either return, or advance to the next bytecode and dispatch.
    Label do_return;
    __ movzxbq(rbx, Operand(kInterpreterBytecodeArrayRegister,
                            kInterpreterBytecodeOffsetRegister, times_1, 0));
    AdvanceBytecodeOffsetOrReturn(masm, kInterpreterBytecodeArrayRegister,
                                  kInterpreterBytecodeOffsetRegister, rbx, rcx,
                                  &do_return);
    __ jmp(&do_dispatch);
  
    __ bind(&do_return);
    // The return value is in rax.
    LeaveInterpreterFrame(masm, rbx, rcx);
    __ ret(0);
  
    __ bind(&compile_lazy);
    GenerateTailCallToReturnedCode(masm, Runtime::kCompileLazy);
    __ int3();  // Should not return.
  }
  
  static void Generate_InterpreterPushArgs(MacroAssembler* masm,
                                           Register num_args,
                                           Register start_address,
                                           Register scratch) {
    // Find the address of the last argument.
    __ Move(scratch, num_args);
    __ shlq(scratch, Immediate(kSystemPointerSizeLog2));
    __ negq(scratch);
    __ addq(scratch, start_address);
  
    // Push the arguments.
    Label loop_header, loop_check;
    __ j(always, &loop_check, Label::kNear);
    __ bind(&loop_header);
    __ Push(Operand(start_address, 0));
    __ subq(start_address, Immediate(kSystemPointerSize));
    __ bind(&loop_check);
    __ cmpq(start_address, scratch);
    __ j(greater, &loop_header, Label::kNear);
  }
  
  // static
  void Builtins::Generate_InterpreterPushArgsThenCallImpl(
      MacroAssembler* masm, ConvertReceiverMode receiver_mode,
      InterpreterPushArgsMode mode) {
    DCHECK(mode != InterpreterPushArgsMode::kArrayFunction);
    // ----------- S t a t e -------------
    //  -- rax : the number of arguments (not including the receiver)
    //  -- rbx : the address of the first argument to be pushed. Subsequent
    //           arguments should be consecutive above this, in the same order as
    //           they are to be pushed onto the stack.
    //  -- rdi : the target to call (can be any Object).
    // -----------------------------------
    Label stack_overflow;
  
    // Number of values to be pushed.
    __ leal(rcx, Operand(rax, 1));  // Add one for receiver.
  
    // Add a stack check before pushing arguments.
    Generate_StackOverflowCheck(masm, rcx, rdx, &stack_overflow);
  
    // Pop return address to allow tail-call after pushing arguments.
    __ PopReturnAddressTo(kScratchRegister);
  
    // Push "undefined" as the receiver arg if we need to.
    if (receiver_mode == ConvertReceiverMode::kNullOrUndefined) {
      __ PushRoot(RootIndex::kUndefinedValue);
      __ decl(rcx);  // Subtract one for receiver.
    }
  
    // rbx and rdx will be modified.
    Generate_InterpreterPushArgs(masm, rcx, rbx, rdx);
  
    if (mode == InterpreterPushArgsMode::kWithFinalSpread) {
      __ Pop(rbx);                 // Pass the spread in a register
      __ decl(rax);                // Subtract one for spread
    }
  
    // Call the target.
    __ PushReturnAddressFrom(kScratchRegister);  // Re-push return address.
  
    if (mode == InterpreterPushArgsMode::kWithFinalSpread) {
      __ Jump(BUILTIN_CODE(masm->isolate(), CallWithSpread),
              RelocInfo::CODE_TARGET);
    } else {
      __ Jump(masm->isolate()->builtins()->Call(receiver_mode),
              RelocInfo::CODE_TARGET);
    }
  
    // Throw stack overflow exception.
    __ bind(&stack_overflow);
    {
      __ TailCallRuntime(Runtime::kThrowStackOverflow);
      // This should be unreachable.
      __ int3();
    }
  }
  
  // static
  void Builtins::Generate_InterpreterPushArgsThenConstructImpl(
      MacroAssembler* masm, InterpreterPushArgsMode mode) {
    // ----------- S t a t e -------------
    //  -- rax : the number of arguments (not including the receiver)
    //  -- rdx : the new target (either the same as the constructor or
    //           the JSFunction on which new was invoked initially)
    //  -- rdi : the constructor to call (can be any Object)
    //  -- rbx : the allocation site feedback if available, undefined otherwise
    //  -- rcx : the address of the first argument to be pushed. Subsequent
    //           arguments should be consecutive above this, in the same order as
    //           they are to be pushed onto the stack.
    // -----------------------------------
    Label stack_overflow;
  
    // Add a stack check before pushing arguments.
    Generate_StackOverflowCheck(masm, rax, r8, &stack_overflow);
  
    // Pop return address to allow tail-call after pushing arguments.
    __ PopReturnAddressTo(kScratchRegister);
  
    // Push slot for the receiver to be constructed.
    __ Push(Immediate(0));
  
    // rcx and r8 will be modified.
    Generate_InterpreterPushArgs(masm, rax, rcx, r8);
  
    if (mode == InterpreterPushArgsMode::kWithFinalSpread) {
      __ Pop(rbx);                 // Pass the spread in a register
      __ decl(rax);                // Subtract one for spread
  
      // Push return address in preparation for the tail-call.
      __ PushReturnAddressFrom(kScratchRegister);
    } else {
      __ PushReturnAddressFrom(kScratchRegister);
      __ AssertUndefinedOrAllocationSite(rbx);
    }
  
    if (mode == InterpreterPushArgsMode::kArrayFunction) {
      // Tail call to the array construct stub (still in the caller
      // context at this point).
      __ AssertFunction(rdi);
      // Jump to the constructor function (rax, rbx, rdx passed on).
      Handle<Code> code = BUILTIN_CODE(masm->isolate(), ArrayConstructorImpl);
      __ Jump(code, RelocInfo::CODE_TARGET);
    } else if (mode == InterpreterPushArgsMode::kWithFinalSpread) {
      // Call the constructor (rax, rdx, rdi passed on).
      __ Jump(BUILTIN_CODE(masm->isolate(), ConstructWithSpread),
              RelocInfo::CODE_TARGET);
    } else {
      DCHECK_EQ(InterpreterPushArgsMode::kOther, mode);
      // Call the constructor (rax, rdx, rdi passed on).
      __ Jump(BUILTIN_CODE(masm->isolate(), Construct), RelocInfo::CODE_TARGET);
    }
  
    // Throw stack overflow exception.
    __ bind(&stack_overflow);
    {
      __ TailCallRuntime(Runtime::kThrowStackOverflow);
      // This should be unreachable.
      __ int3();
    }
  }
  
  static void Generate_InterpreterEnterBytecode(MacroAssembler* masm) {
    // Set the return address to the correct point in the interpreter entry
    // trampoline.
    Label builtin_trampoline, trampoline_loaded;
    Smi interpreter_entry_return_pc_offset(
        masm->isolate()->heap()->interpreter_entry_return_pc_offset());
    DCHECK_NE(interpreter_entry_return_pc_offset, Smi::kZero);
  
    Register decompr_scratch_for_debug =
        COMPRESS_POINTERS_BOOL ? kScratchRegister : no_reg;
  
    // If the SFI function_data is an InterpreterData, the function will have a
    // custom copy of the interpreter entry trampoline for profiling. If so,
    // get the custom trampoline, otherwise grab the entry address of the global
    // trampoline.
    __ movq(rbx, Operand(rbp, StandardFrameConstants::kFunctionOffset));
    __ LoadTaggedPointerField(
        rbx, FieldOperand(rbx, JSFunction::kSharedFunctionInfoOffset),
        decompr_scratch_for_debug);
    __ LoadTaggedPointerField(
        rbx, FieldOperand(rbx, SharedFunctionInfo::kFunctionDataOffset),
        decompr_scratch_for_debug);
    __ CmpObjectType(rbx, INTERPRETER_DATA_TYPE, kScratchRegister);
    __ j(not_equal, &builtin_trampoline, Label::kNear);
  
    __ movq(rbx,
            FieldOperand(rbx, InterpreterData::kInterpreterTrampolineOffset));
    __ addq(rbx, Immediate(Code::kHeaderSize - kHeapObjectTag));
    __ jmp(&trampoline_loaded, Label::kNear);
  
    __ bind(&builtin_trampoline);
    // TODO(jgruber): Replace this by a lookup in the builtin entry table.
    __ movq(rbx,
            __ ExternalReferenceAsOperand(
                ExternalReference::
                    address_of_interpreter_entry_trampoline_instruction_start(
                        masm->isolate()),
                kScratchRegister));
  
    __ bind(&trampoline_loaded);
    __ addq(rbx, Immediate(interpreter_entry_return_pc_offset->value()));
    __ Push(rbx);
  
    // Initialize dispatch table register.
    __ Move(
        kInterpreterDispatchTableRegister,
        ExternalReference::interpreter_dispatch_table_address(masm->isolate()));
  
    // Get the bytecode array pointer from the frame.
    __ movq(kInterpreterBytecodeArrayRegister,
            Operand(rbp, InterpreterFrameConstants::kBytecodeArrayFromFp));
  
    if (FLAG_debug_code) {
      // Check function data field is actually a BytecodeArray object.
      __ AssertNotSmi(kInterpreterBytecodeArrayRegister);
      __ CmpObjectType(kInterpreterBytecodeArrayRegister, BYTECODE_ARRAY_TYPE,
                       rbx);
      __ Assert(
          equal,
          AbortReason::kFunctionDataShouldBeBytecodeArrayOnInterpreterEntry);
    }
  
    // Get the target bytecode offset from the frame.
    __ movq(kInterpreterBytecodeOffsetRegister,
            Operand(rbp, InterpreterFrameConstants::kBytecodeOffsetFromFp));
    __ SmiUntag(kInterpreterBytecodeOffsetRegister,
                kInterpreterBytecodeOffsetRegister);
  
    // Dispatch to the target bytecode.
    __ movzxbq(r11, Operand(kInterpreterBytecodeArrayRegister,
                            kInterpreterBytecodeOffsetRegister, times_1, 0));
    __ movq(
        kJavaScriptCallCodeStartRegister,
        Operand(kInterpreterDispatchTableRegister, r11, times_pointer_size, 0));
    __ jmp(kJavaScriptCallCodeStartRegister);
  }
  
  void Builtins::Generate_InterpreterEnterBytecodeAdvance(MacroAssembler* masm) {
    // Get bytecode array and bytecode offset from the stack frame.
    __ movq(kInterpreterBytecodeArrayRegister,
            Operand(rbp, InterpreterFrameConstants::kBytecodeArrayFromFp));
    __ movq(kInterpreterBytecodeOffsetRegister,
            Operand(rbp, InterpreterFrameConstants::kBytecodeOffsetFromFp));
    __ SmiUntag(kInterpreterBytecodeOffsetRegister,
                kInterpreterBytecodeOffsetRegister);
  
    // Load the current bytecode.
    __ movzxbq(rbx, Operand(kInterpreterBytecodeArrayRegister,
                            kInterpreterBytecodeOffsetRegister, times_1, 0));
  
    // Advance to the next bytecode.
    Label if_return;
    AdvanceBytecodeOffsetOrReturn(masm, kInterpreterBytecodeArrayRegister,
                                  kInterpreterBytecodeOffsetRegister, rbx, rcx,
                                  &if_return);
  
    // Convert new bytecode offset to a Smi and save in the stackframe.
    __ SmiTag(rbx, kInterpreterBytecodeOffsetRegister);
    __ movq(Operand(rbp, InterpreterFrameConstants::kBytecodeOffsetFromFp), rbx);
  
    Generate_InterpreterEnterBytecode(masm);
  
    // We should never take the if_return path.
    __ bind(&if_return);
    __ Abort(AbortReason::kInvalidBytecodeAdvance);
  }
  
  void Builtins::Generate_InterpreterEnterBytecodeDispatch(MacroAssembler* masm) {
    Generate_InterpreterEnterBytecode(masm);
  }
  
  void Builtins::Generate_InstantiateAsmJs(MacroAssembler* masm) {
    // ----------- S t a t e -------------
    //  -- rax : argument count (preserved for callee)
    //  -- rdx : new target (preserved for callee)
    //  -- rdi : target function (preserved for callee)
    // -----------------------------------
    Label failed;
    {
      FrameScope scope(masm, StackFrame::INTERNAL);
      // Preserve argument count for later compare.
      __ movq(rcx, rax);
      // Push the number of arguments to the callee.
      __ SmiTag(rax, rax);
      __ Push(rax);
      // Push a copy of the target function and the new target.
      __ Push(rdi);
      __ Push(rdx);
  
      // The function.
      __ Push(rdi);
      // Copy arguments from caller (stdlib, foreign, heap).
      Label args_done;
      for (int j = 0; j < 4; ++j) {
        Label over;
        if (j < 3) {
          __ cmpq(rcx, Immediate(j));
          __ j(not_equal, &over, Label::kNear);
        }
        for (int i = j - 1; i >= 0; --i) {
          __ Push(Operand(rbp, StandardFrameConstants::kCallerSPOffset +
                                   i * kSystemPointerSize));
        }
        for (int i = 0; i < 3 - j; ++i) {
          __ PushRoot(RootIndex::kUndefinedValue);
        }
        if (j < 3) {
          __ jmp(&args_done, Label::kNear);
          __ bind(&over);
        }
      }
      __ bind(&args_done);
  
      // Call runtime, on success unwind frame, and parent frame.
      __ CallRuntime(Runtime::kInstantiateAsmJs, 4);
      // A smi 0 is returned on failure, an object on success.
      __ JumpIfSmi(rax, &failed, Label::kNear);
  
      __ Drop(2);
      __ Pop(rcx);
      __ SmiUntag(rcx, rcx);
      scope.GenerateLeaveFrame();
  
      __ PopReturnAddressTo(rbx);
      __ incq(rcx);
      __ leaq(rsp, Operand(rsp, rcx, times_pointer_size, 0));
      __ PushReturnAddressFrom(rbx);
      __ ret(0);
  
      __ bind(&failed);
      // Restore target function and new target.
      __ Pop(rdx);
      __ Pop(rdi);
      __ Pop(rax);
      __ SmiUntag(rax, rax);
    }
    // On failure, tail call back to regular js by re-calling the function
    // which has be reset to the compile lazy builtin.
    Register decompr_scratch_for_debug =
        COMPRESS_POINTERS_BOOL ? kScratchRegister : no_reg;
    __ LoadTaggedPointerField(rcx, FieldOperand(rdi, JSFunction::kCodeOffset),
                              decompr_scratch_for_debug);
    __ JumpCodeObject(rcx);
  }
  
  namespace {
  void Generate_ContinueToBuiltinHelper(MacroAssembler* masm,
                                        bool java_script_builtin,
                                        bool with_result) {
    const RegisterConfiguration* config(RegisterConfiguration::Default());
    int allocatable_register_count = config->num_allocatable_general_registers();
    if (with_result) {
      // Overwrite the hole inserted by the deoptimizer with the return value from
      // the LAZY deopt point.
      __ movq(
          Operand(rsp, config->num_allocatable_general_registers() *
                               kSystemPointerSize +
                           BuiltinContinuationFrameConstants::kFixedFrameSize),
          rax);
    }
    for (int i = allocatable_register_count - 1; i >= 0; --i) {
      int code = config->GetAllocatableGeneralCode(i);
      __ popq(Register::from_code(code));
      if (java_script_builtin && code == kJavaScriptCallArgCountRegister.code()) {
        __ SmiUntag(Register::from_code(code), Register::from_code(code));
      }
    }
    __ movq(
        rbp,
        Operand(rsp, BuiltinContinuationFrameConstants::kFixedFrameSizeFromFp));
    const int offsetToPC =
        BuiltinContinuationFrameConstants::kFixedFrameSizeFromFp -
        kSystemPointerSize;
    __ popq(Operand(rsp, offsetToPC));
    __ Drop(offsetToPC / kSystemPointerSize);
    __ addq(Operand(rsp, 0), Immediate(Code::kHeaderSize - kHeapObjectTag));
    __ Ret();
  }
  }  // namespace
  
  void Builtins::Generate_ContinueToCodeStubBuiltin(MacroAssembler* masm) {
    Generate_ContinueToBuiltinHelper(masm, false, false);
  }
  
  void Builtins::Generate_ContinueToCodeStubBuiltinWithResult(
      MacroAssembler* masm) {
    Generate_ContinueToBuiltinHelper(masm, false, true);
  }
  
  void Builtins::Generate_ContinueToJavaScriptBuiltin(MacroAssembler* masm) {
    Generate_ContinueToBuiltinHelper(masm, true, false);
  }
  
  void Builtins::Generate_ContinueToJavaScriptBuiltinWithResult(
      MacroAssembler* masm) {
    Generate_ContinueToBuiltinHelper(masm, true, true);
  }
  
  void Builtins::Generate_NotifyDeoptimized(MacroAssembler* masm) {
    // Enter an internal frame.
    {
      FrameScope scope(masm, StackFrame::INTERNAL);
      __ CallRuntime(Runtime::kNotifyDeoptimized);
      // Tear down internal frame.
    }
  
    DCHECK_EQ(kInterpreterAccumulatorRegister.code(), rax.code());
    __ movq(rax, Operand(rsp, kPCOnStackSize));
    __ ret(1 * kSystemPointerSize);  // Remove rax.
  }
  
  // static
  void Builtins::Generate_FunctionPrototypeApply(MacroAssembler* masm) {
    // ----------- S t a t e -------------
    //  -- rax     : argc
    //  -- rsp[0]  : return address
    //  -- rsp[8]  : argArray
    //  -- rsp[16] : thisArg
    //  -- rsp[24] : receiver
    // -----------------------------------
  
    // 1. Load receiver into rdi, argArray into rbx (if present), remove all
    // arguments from the stack (including the receiver), and push thisArg (if
    // present) instead.
    {
      Label no_arg_array, no_this_arg;
      StackArgumentsAccessor args(rsp, rax);
      __ LoadRoot(rdx, RootIndex::kUndefinedValue);
      __ movq(rbx, rdx);
      __ movq(rdi, args.GetReceiverOperand());
      __ testq(rax, rax);
      __ j(zero, &no_this_arg, Label::kNear);
      {
        __ movq(rdx, args.GetArgumentOperand(1));
        __ cmpq(rax, Immediate(1));
        __ j(equal, &no_arg_array, Label::kNear);
        __ movq(rbx, args.GetArgumentOperand(2));
        __ bind(&no_arg_array);
      }
      __ bind(&no_this_arg);
      __ PopReturnAddressTo(rcx);
      __ leaq(rsp, Operand(rsp, rax, times_pointer_size, kSystemPointerSize));
      __ Push(rdx);
      __ PushReturnAddressFrom(rcx);
    }
  
    // ----------- S t a t e -------------
    //  -- rbx     : argArray
    //  -- rdi     : receiver
    //  -- rsp[0]  : return address
    //  -- rsp[8]  : thisArg
    // -----------------------------------
  
    // 2. We don't need to check explicitly for callable receiver here,
    // since that's the first thing the Call/CallWithArrayLike builtins
    // will do.
  
    // 3. Tail call with no arguments if argArray is null or undefined.
    Label no_arguments;
    __ JumpIfRoot(rbx, RootIndex::kNullValue, &no_arguments, Label::kNear);
    __ JumpIfRoot(rbx, RootIndex::kUndefinedValue, &no_arguments, Label::kNear);
  
    // 4a. Apply the receiver to the given argArray.
    __ Jump(BUILTIN_CODE(masm->isolate(), CallWithArrayLike),
            RelocInfo::CODE_TARGET);
  
    // 4b. The argArray is either null or undefined, so we tail call without any
    // arguments to the receiver. Since we did not create a frame for
    // Function.prototype.apply() yet, we use a normal Call builtin here.
    __ bind(&no_arguments);
    {
      __ Set(rax, 0);
      __ Jump(masm->isolate()->builtins()->Call(), RelocInfo::CODE_TARGET);
    }
  }
  
  // static
  void Builtins::Generate_FunctionPrototypeCall(MacroAssembler* masm) {
    // Stack Layout:
    // rsp[0]           : Return address
    // rsp[8]           : Argument n
    // rsp[16]          : Argument n-1
    //  ...
    // rsp[8 * n]       : Argument 1
    // rsp[8 * (n + 1)] : Receiver (callable to call)
    //
    // rax contains the number of arguments, n, not counting the receiver.
    //
    // 1. Make sure we have at least one argument.
    {
      Label done;
      __ testq(rax, rax);
      __ j(not_zero, &done, Label::kNear);
      __ PopReturnAddressTo(rbx);
      __ PushRoot(RootIndex::kUndefinedValue);
      __ PushReturnAddressFrom(rbx);
      __ incq(rax);
      __ bind(&done);
    }
  
    // 2. Get the callable to call (passed as receiver) from the stack.
    {
      StackArgumentsAccessor args(rsp, rax);
      __ movq(rdi, args.GetReceiverOperand());
    }
  
    // 3. Shift arguments and return address one slot down on the stack
    //    (overwriting the original receiver).  Adjust argument count to make
    //    the original first argument the new receiver.
    {
      Label loop;
      __ movq(rcx, rax);
      StackArgumentsAccessor args(rsp, rcx);
      __ bind(&loop);
      __ movq(rbx, args.GetArgumentOperand(1));
      __ movq(args.GetArgumentOperand(0), rbx);
      __ decq(rcx);
      __ j(not_zero, &loop);              // While non-zero.
      __ DropUnderReturnAddress(1, rbx);  // Drop one slot under return address.
      __ decq(rax);  // One fewer argument (first argument is new receiver).
    }
  
    // 4. Call the callable.
    // Since we did not create a frame for Function.prototype.call() yet,
    // we use a normal Call builtin here.
    __ Jump(masm->isolate()->builtins()->Call(), RelocInfo::CODE_TARGET);
  }
  
  void Builtins::Generate_ReflectApply(MacroAssembler* masm) {
    // ----------- S t a t e -------------
    //  -- rax     : argc
    //  -- rsp[0]  : return address
    //  -- rsp[8]  : argumentsList
    //  -- rsp[16] : thisArgument
    //  -- rsp[24] : target
    //  -- rsp[32] : receiver
    // -----------------------------------
  
    // 1. Load target into rdi (if present), argumentsList into rbx (if present),
    // remove all arguments from the stack (including the receiver), and push
    // thisArgument (if present) instead.
    {
      Label done;
      StackArgumentsAccessor args(rsp, rax);
      __ LoadRoot(rdi, RootIndex::kUndefinedValue);
      __ movq(rdx, rdi);
      __ movq(rbx, rdi);
      __ cmpq(rax, Immediate(1));
      __ j(below, &done, Label::kNear);
      __ movq(rdi, args.GetArgumentOperand(1));  // target
      __ j(equal, &done, Label::kNear);
      __ movq(rdx, args.GetArgumentOperand(2));  // thisArgument
      __ cmpq(rax, Immediate(3));
      __ j(below, &done, Label::kNear);
      __ movq(rbx, args.GetArgumentOperand(3));  // argumentsList
      __ bind(&done);
      __ PopReturnAddressTo(rcx);
      __ leaq(rsp, Operand(rsp, rax, times_pointer_size, kSystemPointerSize));
      __ Push(rdx);
      __ PushReturnAddressFrom(rcx);
    }
  
    // ----------- S t a t e -------------
    //  -- rbx     : argumentsList
    //  -- rdi     : target
    //  -- rsp[0]  : return address
    //  -- rsp[8]  : thisArgument
    // -----------------------------------
  
    // 2. We don't need to check explicitly for callable target here,
    // since that's the first thing the Call/CallWithArrayLike builtins
    // will do.
  
    // 3. Apply the target to the given argumentsList.
    __ Jump(BUILTIN_CODE(masm->isolate(), CallWithArrayLike),
            RelocInfo::CODE_TARGET);
  }
  
  void Builtins::Generate_ReflectConstruct(MacroAssembler* masm) {
    // ----------- S t a t e -------------
    //  -- rax     : argc
    //  -- rsp[0]  : return address
    //  -- rsp[8]  : new.target (optional)
    //  -- rsp[16] : argumentsList
    //  -- rsp[24] : target
    //  -- rsp[32] : receiver
    // -----------------------------------
  
    // 1. Load target into rdi (if present), argumentsList into rbx (if present),
    // new.target into rdx (if present, otherwise use target), remove all
    // arguments from the stack (including the receiver), and push thisArgument
    // (if present) instead.
    {
      Label done;
      StackArgumentsAccessor args(rsp, rax);
      __ LoadRoot(rdi, RootIndex::kUndefinedValue);
      __ movq(rdx, rdi);
      __ movq(rbx, rdi);
      __ cmpq(rax, Immediate(1));
      __ j(below, &done, Label::kNear);
      __ movq(rdi, args.GetArgumentOperand(1));  // target
      __ movq(rdx, rdi);                         // new.target defaults to target
      __ j(equal, &done, Label::kNear);
      __ movq(rbx, args.GetArgumentOperand(2));  // argumentsList
      __ cmpq(rax, Immediate(3));
      __ j(below, &done, Label::kNear);
      __ movq(rdx, args.GetArgumentOperand(3));  // new.target
      __ bind(&done);
      __ PopReturnAddressTo(rcx);
      __ leaq(rsp, Operand(rsp, rax, times_pointer_size, kSystemPointerSize));
      __ PushRoot(RootIndex::kUndefinedValue);
      __ PushReturnAddressFrom(rcx);
    }
  
    // ----------- S t a t e -------------
    //  -- rbx     : argumentsList
    //  -- rdx     : new.target
    //  -- rdi     : target
    //  -- rsp[0]  : return address
    //  -- rsp[8]  : receiver (undefined)
    // -----------------------------------
  
    // 2. We don't need to check explicitly for constructor target here,
    // since that's the first thing the Construct/ConstructWithArrayLike
    // builtins will do.
  
    // 3. We don't need to check explicitly for constructor new.target here,
    // since that's the second thing the Construct/ConstructWithArrayLike
    // builtins will do.
  
    // 4. Construct the target with the given new.target and argumentsList.
    __ Jump(BUILTIN_CODE(masm->isolate(), ConstructWithArrayLike),
            RelocInfo::CODE_TARGET);
  }
  
  void Builtins::Generate_InternalArrayConstructor(MacroAssembler* masm) {
    // ----------- S t a t e -------------
    //  -- rax    : argc
    //  -- rsp[0] : return address
    //  -- rsp[8] : last argument
    // -----------------------------------
  
    if (FLAG_debug_code) {
      Register decompr_scratch_for_debug =
          COMPRESS_POINTERS_BOOL ? kScratchRegister : no_reg;
      // Initial map for the builtin InternalArray functions should be maps.
      __ LoadTaggedPointerField(
          rbx, FieldOperand(rdi, JSFunction::kPrototypeOrInitialMapOffset),
          decompr_scratch_for_debug);
      // Will both indicate a nullptr and a Smi.
      STATIC_ASSERT(kSmiTag == 0);
      Condition not_smi = NegateCondition(masm->CheckSmi(rbx));
      __ Check(not_smi,
               AbortReason::kUnexpectedInitialMapForInternalArrayFunction);
      __ CmpObjectType(rbx, MAP_TYPE, rcx);
      __ Check(equal, AbortReason::kUnexpectedInitialMapForInternalArrayFunction);
    }
  
    // Run the native code for the InternalArray function called as a normal
    // function.
    __ Jump(BUILTIN_CODE(masm->isolate(), InternalArrayConstructorImpl),
            RelocInfo::CODE_TARGET);
  }
  
  static void EnterArgumentsAdaptorFrame(MacroAssembler* masm) {
    __ pushq(rbp);
    __ movq(rbp, rsp);
  
    // Store the arguments adaptor context sentinel.
    __ Push(Immediate(StackFrame::TypeToMarker(StackFrame::ARGUMENTS_ADAPTOR)));
  
    // Push the function on the stack.
    __ Push(rdi);
  
    // Preserve the number of arguments on the stack. Must preserve rax,
    // rbx and rcx because these registers are used when copying the
    // arguments and the receiver.
    __ SmiTag(r8, rax);
    __ Push(r8);
  
    __ Push(Immediate(0));  // Padding.
  }
  
  static void LeaveArgumentsAdaptorFrame(MacroAssembler* masm) {
    // Retrieve the number of arguments from the stack. Number is a Smi.
    __ movq(rbx, Operand(rbp, ArgumentsAdaptorFrameConstants::kLengthOffset));
  
    // Leave the frame.
    __ movq(rsp, rbp);
    __ popq(rbp);
  
    // Remove caller arguments from the stack.
    __ PopReturnAddressTo(rcx);
    SmiIndex index = masm->SmiToIndex(rbx, rbx, kSystemPointerSizeLog2);
    __ leaq(rsp, Operand(rsp, index.reg, index.scale, 1 * kSystemPointerSize));
    __ PushReturnAddressFrom(rcx);
  }
  
  void Builtins::Generate_ArgumentsAdaptorTrampoline(MacroAssembler* masm) {
    // ----------- S t a t e -------------
    //  -- rax : actual number of arguments
    //  -- rbx : expected number of arguments
    //  -- rdx : new target (passed through to callee)
    //  -- rdi : function (passed through to callee)
    // -----------------------------------
  
    Register decompr_scratch_for_debug =
        COMPRESS_POINTERS_BOOL ? kScratchRegister : no_reg;
  
    Label invoke, dont_adapt_arguments, stack_overflow, enough, too_few;
    __ cmpq(rbx, Immediate(SharedFunctionInfo::kDontAdaptArgumentsSentinel));
    __ j(equal, &dont_adapt_arguments);
    __ cmpq(rax, rbx);
    __ j(less, &too_few);
  
    {  // Enough parameters: Actual >= expected.
      __ bind(&enough);
      EnterArgumentsAdaptorFrame(masm);
      // The registers rcx and r8 will be modified. The register rbx is only read.
      Generate_StackOverflowCheck(masm, rbx, rcx, &stack_overflow);
  
      // Copy receiver and all expected arguments.
      const int offset = StandardFrameConstants::kCallerSPOffset;
      __ leaq(rax, Operand(rbp, rax, times_pointer_size, offset));
      __ Set(r8, -1);  // account for receiver
  
      Label copy;
      __ bind(&copy);
      __ incq(r8);
      __ Push(Operand(rax, 0));
      __ subq(rax, Immediate(kSystemPointerSize));
      __ cmpq(r8, rbx);
      __ j(less, &copy);
      __ jmp(&invoke);
    }
  
    {  // Too few parameters: Actual < expected.
      __ bind(&too_few);
  
      EnterArgumentsAdaptorFrame(masm);
      // The registers rcx and r8 will be modified. The register rbx is only read.
      Generate_StackOverflowCheck(masm, rbx, rcx, &stack_overflow);
  
      // Copy receiver and all actual arguments.
      const int offset = StandardFrameConstants::kCallerSPOffset;
      __ leaq(rdi, Operand(rbp, rax, times_pointer_size, offset));
      __ Set(r8, -1);  // account for receiver
  
      Label copy;
      __ bind(&copy);
      __ incq(r8);
      __ Push(Operand(rdi, 0));
      __ subq(rdi, Immediate(kSystemPointerSize));
      __ cmpq(r8, rax);
      __ j(less, &copy);
  
      // Fill remaining expected arguments with undefined values.
      Label fill;
      __ LoadRoot(kScratchRegister, RootIndex::kUndefinedValue);
      __ bind(&fill);
      __ incq(r8);
      __ Push(kScratchRegister);
      __ cmpq(r8, rbx);
      __ j(less, &fill);
  
      // Restore function pointer.
      __ movq(rdi, Operand(rbp, ArgumentsAdaptorFrameConstants::kFunctionOffset));
    }
  
    // Call the entry point.
    __ bind(&invoke);
    __ movq(rax, rbx);
    // rax : expected number of arguments
    // rdx : new target (passed through to callee)
    // rdi : function (passed through to callee)
    static_assert(kJavaScriptCallCodeStartRegister == rcx, "ABI mismatch");
    __ LoadTaggedPointerField(rcx, FieldOperand(rdi, JSFunction::kCodeOffset),
                              decompr_scratch_for_debug);
    __ CallCodeObject(rcx);
  
    // Store offset of return address for deoptimizer.
    masm->isolate()->heap()->SetArgumentsAdaptorDeoptPCOffset(masm->pc_offset());
  
    // Leave frame and return.
    LeaveArgumentsAdaptorFrame(masm);
    __ ret(0);
  
    // -------------------------------------------
    // Dont adapt arguments.
    // -------------------------------------------
    __ bind(&dont_adapt_arguments);
    static_assert(kJavaScriptCallCodeStartRegister == rcx, "ABI mismatch");
    __ LoadTaggedPointerField(rcx, FieldOperand(rdi, JSFunction::kCodeOffset),
                              decompr_scratch_for_debug);
    __ JumpCodeObject(rcx);
  
    __ bind(&stack_overflow);
    {
      FrameScope frame(masm, StackFrame::MANUAL);
      __ CallRuntime(Runtime::kThrowStackOverflow);
      __ int3();
    }
  }
  
  // static
  void Builtins::Generate_CallOrConstructVarargs(MacroAssembler* masm,
                                                 Handle<Code> code) {
    // ----------- S t a t e -------------
    //  -- rdi    : target
    //  -- rax    : number of parameters on the stack (not including the receiver)
    //  -- rbx    : arguments list (a FixedArray)
    //  -- rcx    : len (number of elements to push from args)
    //  -- rdx    : new.target (for [[Construct]])
    //  -- rsp[0] : return address
    // -----------------------------------
    Register scratch = r11;
    Register decompr_scratch = COMPRESS_POINTERS_BOOL ? r12 : no_reg;
    Register decompr_scratch_for_debug =
        COMPRESS_POINTERS_BOOL ? kScratchRegister : no_reg;
  
    if (masm->emit_debug_code()) {
      // Allow rbx to be a FixedArray, or a FixedDoubleArray if rcx == 0.
      Label ok, fail;
      __ AssertNotSmi(rbx);
      Register map = r9;
      __ LoadTaggedPointerField(map, FieldOperand(rbx, HeapObject::kMapOffset),
                                decompr_scratch_for_debug);
      __ CmpInstanceType(map, FIXED_ARRAY_TYPE);
      __ j(equal, &ok);
      __ CmpInstanceType(map, FIXED_DOUBLE_ARRAY_TYPE);
      __ j(not_equal, &fail);
      __ cmpl(rcx, Immediate(0));
      __ j(equal, &ok);
      // Fall through.
      __ bind(&fail);
      __ Abort(AbortReason::kOperandIsNotAFixedArray);
  
      __ bind(&ok);
    }
  
    Label stack_overflow;
    Generate_StackOverflowCheck(masm, rcx, r8, &stack_overflow, Label::kNear);
  
    // Push additional arguments onto the stack.
    {
      Register value = scratch;
      __ PopReturnAddressTo(r8);
      __ Set(r9, 0);
      Label done, push, loop;
      __ bind(&loop);
      __ cmpl(r9, rcx);
      __ j(equal, &done, Label::kNear);
      // Turn the hole into undefined as we go.
      __ LoadAnyTaggedField(
          value,
          FieldOperand(rbx, r9, times_tagged_size, FixedArray::kHeaderSize),
          decompr_scratch, decompr_scratch_for_debug);
      __ CompareRoot(value, RootIndex::kTheHoleValue);
      __ j(not_equal, &push, Label::kNear);
      __ LoadRoot(value, RootIndex::kUndefinedValue);
      __ bind(&push);
      __ Push(value);
      __ incl(r9);
      __ jmp(&loop);
      __ bind(&done);
      __ PushReturnAddressFrom(r8);
      __ addq(rax, r9);
    }
  
    // Tail-call to the actual Call or Construct builtin.
    __ Jump(code, RelocInfo::CODE_TARGET);
  
    __ bind(&stack_overflow);
    __ TailCallRuntime(Runtime::kThrowStackOverflow);
  }
  
  // static
  void Builtins::Generate_CallOrConstructForwardVarargs(MacroAssembler* masm,
                                                        CallOrConstructMode mode,
                                                        Handle<Code> code) {
    // ----------- S t a t e -------------
    //  -- rax : the number of arguments (not including the receiver)
    //  -- rdx : the new target (for [[Construct]] calls)
    //  -- rdi : the target to call (can be any Object)
    //  -- rcx : start index (to support rest parameters)
    // -----------------------------------
  
    Register decompr_scratch_for_debug =
        COMPRESS_POINTERS_BOOL ? kScratchRegister : no_reg;
  
    // Check if new.target has a [[Construct]] internal method.
    if (mode == CallOrConstructMode::kConstruct) {
      Label new_target_constructor, new_target_not_constructor;
      __ JumpIfSmi(rdx, &new_target_not_constructor, Label::kNear);
      __ LoadTaggedPointerField(rbx, FieldOperand(rdx, HeapObject::kMapOffset),
                                decompr_scratch_for_debug);
      __ testb(FieldOperand(rbx, Map::kBitFieldOffset),
               Immediate(Map::IsConstructorBit::kMask));
      __ j(not_zero, &new_target_constructor, Label::kNear);
      __ bind(&new_target_not_constructor);
      {
        FrameScope scope(masm, StackFrame::MANUAL);
        __ EnterFrame(StackFrame::INTERNAL);
        __ Push(rdx);
        __ CallRuntime(Runtime::kThrowNotConstructor);
      }
      __ bind(&new_target_constructor);
    }
  
    // Check if we have an arguments adaptor frame below the function frame.
    Label arguments_adaptor, arguments_done;
    __ movq(rbx, Operand(rbp, StandardFrameConstants::kCallerFPOffset));
    __ cmpq(Operand(rbx, CommonFrameConstants::kContextOrFrameTypeOffset),
            Immediate(StackFrame::TypeToMarker(StackFrame::ARGUMENTS_ADAPTOR)));
    __ j(equal, &arguments_adaptor, Label::kNear);
    {
      __ movq(r8, Operand(rbp, JavaScriptFrameConstants::kFunctionOffset));
      __ LoadTaggedPointerField(
          r8, FieldOperand(r8, JSFunction::kSharedFunctionInfoOffset),
          decompr_scratch_for_debug);
      __ movzxwq(
          r8, FieldOperand(r8, SharedFunctionInfo::kFormalParameterCountOffset));
      __ movq(rbx, rbp);
    }
    __ jmp(&arguments_done, Label::kNear);
    __ bind(&arguments_adaptor);
    {
      __ SmiUntag(r8,
                  Operand(rbx, ArgumentsAdaptorFrameConstants::kLengthOffset));
    }
    __ bind(&arguments_done);
  
    Label stack_done, stack_overflow;
    __ subl(r8, rcx);
    __ j(less_equal, &stack_done);
    {
      // Check for stack overflow.
      Generate_StackOverflowCheck(masm, r8, rcx, &stack_overflow, Label::kNear);
  
      // Forward the arguments from the caller frame.
      {
        Label loop;
        __ addl(rax, r8);
        __ PopReturnAddressTo(rcx);
        __ bind(&loop);
        {
          StackArgumentsAccessor args(rbx, r8, ARGUMENTS_DONT_CONTAIN_RECEIVER);
          __ Push(args.GetArgumentOperand(0));
          __ decl(r8);
          __ j(not_zero, &loop);
        }
        __ PushReturnAddressFrom(rcx);
      }
    }
    __ jmp(&stack_done, Label::kNear);
    __ bind(&stack_overflow);
    __ TailCallRuntime(Runtime::kThrowStackOverflow);
    __ bind(&stack_done);
  
    // Tail-call to the {code} handler.
    __ Jump(code, RelocInfo::CODE_TARGET);
  }
  
  // static
  void Builtins::Generate_CallFunction(MacroAssembler* masm,
                                       ConvertReceiverMode mode) {
    // ----------- S t a t e -------------
    //  -- rax : the number of arguments (not including the receiver)
    //  -- rdi : the function to call (checked to be a JSFunction)
    // -----------------------------------
    Register decompr_scratch_for_debug =
        COMPRESS_POINTERS_BOOL ? kScratchRegister : no_reg;
  
    StackArgumentsAccessor args(rsp, rax);
    __ AssertFunction(rdi);
  
    // ES6 section 9.2.1 [[Call]] ( thisArgument, argumentsList)
    // Check that the function is not a "classConstructor".
    Label class_constructor;
    __ LoadTaggedPointerField(
        rdx, FieldOperand(rdi, JSFunction::kSharedFunctionInfoOffset),
        decompr_scratch_for_debug);
    __ testl(FieldOperand(rdx, SharedFunctionInfo::kFlagsOffset),
             Immediate(SharedFunctionInfo::IsClassConstructorBit::kMask));
    __ j(not_zero, &class_constructor);
  
    // ----------- S t a t e -------------
    //  -- rax : the number of arguments (not including the receiver)
    //  -- rdx : the shared function info.
    //  -- rdi : the function to call (checked to be a JSFunction)
    // -----------------------------------
  
    // Enter the context of the function; ToObject has to run in the function
    // context, and we also need to take the global proxy from the function
    // context in case of conversion.
    __ LoadTaggedPointerField(rsi, FieldOperand(rdi, JSFunction::kContextOffset),
                              decompr_scratch_for_debug);
    // We need to convert the receiver for non-native sloppy mode functions.
    Label done_convert;
    __ testl(FieldOperand(rdx, SharedFunctionInfo::kFlagsOffset),
             Immediate(SharedFunctionInfo::IsNativeBit::kMask |
                       SharedFunctionInfo::IsStrictBit::kMask));
    __ j(not_zero, &done_convert);
    {
      // ----------- S t a t e -------------
      //  -- rax : the number of arguments (not including the receiver)
      //  -- rdx : the shared function info.
      //  -- rdi : the function to call (checked to be a JSFunction)
      //  -- rsi : the function context.
      // -----------------------------------
  
      if (mode == ConvertReceiverMode::kNullOrUndefined) {
        // Patch receiver to global proxy.
        __ LoadGlobalProxy(rcx);
      } else {
        Label convert_to_object, convert_receiver;
        __ movq(rcx, args.GetReceiverOperand());
        __ JumpIfSmi(rcx, &convert_to_object, Label::kNear);
        STATIC_ASSERT(LAST_JS_RECEIVER_TYPE == LAST_TYPE);
        __ CmpObjectType(rcx, FIRST_JS_RECEIVER_TYPE, rbx);
        __ j(above_equal, &done_convert);
        if (mode != ConvertReceiverMode::kNotNullOrUndefined) {
          Label convert_global_proxy;
          __ JumpIfRoot(rcx, RootIndex::kUndefinedValue, &convert_global_proxy,
                        Label::kNear);
          __ JumpIfNotRoot(rcx, RootIndex::kNullValue, &convert_to_object,
                           Label::kNear);
          __ bind(&convert_global_proxy);
          {
            // Patch receiver to global proxy.
            __ LoadGlobalProxy(rcx);
          }
          __ jmp(&convert_receiver);
        }
        __ bind(&convert_to_object);
        {
          // Convert receiver using ToObject.
          // TODO(bmeurer): Inline the allocation here to avoid building the frame
          // in the fast case? (fall back to AllocateInNewSpace?)
          FrameScope scope(masm, StackFrame::INTERNAL);
          __ SmiTag(rax, rax);
          __ Push(rax);
          __ Push(rdi);
          __ movq(rax, rcx);
          __ Push(rsi);
          __ Call(BUILTIN_CODE(masm->isolate(), ToObject),
                  RelocInfo::CODE_TARGET);
          __ Pop(rsi);
          __ movq(rcx, rax);
          __ Pop(rdi);
          __ Pop(rax);
          __ SmiUntag(rax, rax);
        }
        __ LoadTaggedPointerField(
            rdx, FieldOperand(rdi, JSFunction::kSharedFunctionInfoOffset),
            decompr_scratch_for_debug);
        __ bind(&convert_receiver);
      }
      __ movq(args.GetReceiverOperand(), rcx);
    }
    __ bind(&done_convert);
  
    // ----------- S t a t e -------------
    //  -- rax : the number of arguments (not including the receiver)
    //  -- rdx : the shared function info.
    //  -- rdi : the function to call (checked to be a JSFunction)
    //  -- rsi : the function context.
    // -----------------------------------
  
    __ movzxwq(
        rbx, FieldOperand(rdx, SharedFunctionInfo::kFormalParameterCountOffset));
    ParameterCount actual(rax);
    ParameterCount expected(rbx);
  
    __ InvokeFunctionCode(rdi, no_reg, expected, actual, JUMP_FUNCTION);
  
    // The function is a "classConstructor", need to raise an exception.
    __ bind(&class_constructor);
    {
      FrameScope frame(masm, StackFrame::INTERNAL);
      __ Push(rdi);
      __ CallRuntime(Runtime::kThrowConstructorNonCallableError);
    }
  }
  
  namespace {
  
  void Generate_PushBoundArguments(MacroAssembler* masm) {
    // ----------- S t a t e -------------
    //  -- rax : the number of arguments (not including the receiver)
    //  -- rdx : new.target (only in case of [[Construct]])
    //  -- rdi : target (checked to be a JSBoundFunction)
    // -----------------------------------
  
    Register decompr_scratch = COMPRESS_POINTERS_BOOL ? r11 : no_reg;
    Register decompr_scratch_for_debug =
        COMPRESS_POINTERS_BOOL ? kScratchRegister : no_reg;
  
    // Load [[BoundArguments]] into rcx and length of that into rbx.
    Label no_bound_arguments;
    __ LoadTaggedPointerField(
        rcx, FieldOperand(rdi, JSBoundFunction::kBoundArgumentsOffset),
        decompr_scratch_for_debug);
    __ SmiUntagField(rbx, FieldOperand(rcx, FixedArray::kLengthOffset));
    __ testl(rbx, rbx);
    __ j(zero, &no_bound_arguments);
    {
      // ----------- S t a t e -------------
      //  -- rax : the number of arguments (not including the receiver)
      //  -- rdx : new.target (only in case of [[Construct]])
      //  -- rdi : target (checked to be a JSBoundFunction)
      //  -- rcx : the [[BoundArguments]] (implemented as FixedArray)
      //  -- rbx : the number of [[BoundArguments]] (checked to be non-zero)
      // -----------------------------------
  
      // Reserve stack space for the [[BoundArguments]].
      {
        Label done;
        __ leaq(kScratchRegister, Operand(rbx, times_pointer_size, 0));
        __ subq(rsp, kScratchRegister);
        // Check the stack for overflow. We are not trying to catch interruptions
        // (i.e. debug break and preemption) here, so check the "real stack
        // limit".
        __ CompareRoot(rsp, RootIndex::kRealStackLimit);
        __ j(above_equal, &done, Label::kNear);
        // Restore the stack pointer.
        __ leaq(rsp, Operand(rsp, rbx, times_pointer_size, 0));
        {
          FrameScope scope(masm, StackFrame::MANUAL);
          __ EnterFrame(StackFrame::INTERNAL);
          __ CallRuntime(Runtime::kThrowStackOverflow);
        }
        __ bind(&done);
      }
  
      // Adjust effective number of arguments to include return address.
      __ incl(rax);
  
      // Relocate arguments and return address down the stack.
      {
        Label loop;
        __ Set(rcx, 0);
        __ leaq(rbx, Operand(rsp, rbx, times_pointer_size, 0));
        __ bind(&loop);
        __ movq(kScratchRegister, Operand(rbx, rcx, times_pointer_size, 0));
        __ movq(Operand(rsp, rcx, times_pointer_size, 0), kScratchRegister);
        __ incl(rcx);
        __ cmpl(rcx, rax);
        __ j(less, &loop);
      }
  
      // Copy [[BoundArguments]] to the stack (below the arguments).
      {
        Label loop;
        __ LoadTaggedPointerField(
            rcx, FieldOperand(rdi, JSBoundFunction::kBoundArgumentsOffset),
            decompr_scratch_for_debug);
        __ SmiUntagField(rbx, FieldOperand(rcx, FixedArray::kLengthOffset));
        __ bind(&loop);
        // Instead of doing decl(rbx) here subtract kTaggedSize from the header
        // offset in order to move be able to move decl(rbx) right before the loop
        // condition. This is necessary in order to avoid flags corruption by
        // pointer decompression code.
        __ LoadAnyTaggedField(r12,
                              FieldOperand(rcx, rbx, times_tagged_size,
                                           FixedArray::kHeaderSize - kTaggedSize),
                              decompr_scratch, decompr_scratch_for_debug);
        __ movq(Operand(rsp, rax, times_pointer_size, 0), r12);
        __ leal(rax, Operand(rax, 1));
        __ decl(rbx);
        __ j(greater, &loop);
      }
  
      // Adjust effective number of arguments (rax contains the number of
      // arguments from the call plus return address plus the number of
      // [[BoundArguments]]), so we need to subtract one for the return address.
      __ decl(rax);
    }
    __ bind(&no_bound_arguments);
  }
  
  }  // namespace
  
  // static
  void Builtins::Generate_CallBoundFunctionImpl(MacroAssembler* masm) {
    // ----------- S t a t e -------------
    //  -- rax : the number of arguments (not including the receiver)
    //  -- rdi : the function to call (checked to be a JSBoundFunction)
    // -----------------------------------
    __ AssertBoundFunction(rdi);
  
    Register decompr_scratch = COMPRESS_POINTERS_BOOL ? r11 : no_reg;
    Register decompr_scratch_for_debug =
        COMPRESS_POINTERS_BOOL ? kScratchRegister : no_reg;
  
    // Patch the receiver to [[BoundThis]].
    StackArgumentsAccessor args(rsp, rax);
    __ LoadAnyTaggedField(rbx,
                          FieldOperand(rdi, JSBoundFunction::kBoundThisOffset),
                          decompr_scratch, decompr_scratch_for_debug);
    __ movq(args.GetReceiverOperand(), rbx);
  
    // Push the [[BoundArguments]] onto the stack.
    Generate_PushBoundArguments(masm);
  
    // Call the [[BoundTargetFunction]] via the Call builtin.
    __ LoadTaggedPointerField(
        rdi, FieldOperand(rdi, JSBoundFunction::kBoundTargetFunctionOffset),
        decompr_scratch_for_debug);
    __ Jump(BUILTIN_CODE(masm->isolate(), Call_ReceiverIsAny),
            RelocInfo::CODE_TARGET);
  }
  
  // static
  void Builtins::Generate_Call(MacroAssembler* masm, ConvertReceiverMode mode) {
    // ----------- S t a t e -------------
    //  -- rax : the number of arguments (not including the receiver)
    //  -- rdi : the target to call (can be any Object)
    // -----------------------------------
    StackArgumentsAccessor args(rsp, rax);
  
    Label non_callable;
    __ JumpIfSmi(rdi, &non_callable);
    __ CmpObjectType(rdi, JS_FUNCTION_TYPE, rcx);
    __ Jump(masm->isolate()->builtins()->CallFunction(mode),
            RelocInfo::CODE_TARGET, equal);
  
    __ CmpInstanceType(rcx, JS_BOUND_FUNCTION_TYPE);
    __ Jump(BUILTIN_CODE(masm->isolate(), CallBoundFunction),
            RelocInfo::CODE_TARGET, equal);
  
    // Check if target has a [[Call]] internal method.
    __ testb(FieldOperand(rcx, Map::kBitFieldOffset),
             Immediate(Map::IsCallableBit::kMask));
    __ j(zero, &non_callable, Label::kNear);
  
    // Check if target is a proxy and call CallProxy external builtin
    __ CmpInstanceType(rcx, JS_PROXY_TYPE);
    __ Jump(BUILTIN_CODE(masm->isolate(), CallProxy), RelocInfo::CODE_TARGET,
            equal);
  
    // 2. Call to something else, which might have a [[Call]] internal method (if
    // not we raise an exception).
  
    // Overwrite the original receiver with the (original) target.
    __ movq(args.GetReceiverOperand(), rdi);
    // Let the "call_as_function_delegate" take care of the rest.
    __ LoadNativeContextSlot(Context::CALL_AS_FUNCTION_DELEGATE_INDEX, rdi);
    __ Jump(masm->isolate()->builtins()->CallFunction(
                ConvertReceiverMode::kNotNullOrUndefined),
            RelocInfo::CODE_TARGET);
  
    // 3. Call to something that is not callable.
    __ bind(&non_callable);
    {
      FrameScope scope(masm, StackFrame::INTERNAL);
      __ Push(rdi);
      __ CallRuntime(Runtime::kThrowCalledNonCallable);
    }
  }
  
  // static
  void Builtins::Generate_ConstructFunction(MacroAssembler* masm) {
    // ----------- S t a t e -------------
    //  -- rax : the number of arguments (not including the receiver)
    //  -- rdx : the new target (checked to be a constructor)
    //  -- rdi : the constructor to call (checked to be a JSFunction)
    // -----------------------------------
    __ AssertConstructor(rdi);
    __ AssertFunction(rdi);
  
    Register decompr_scratch_for_debug =
        COMPRESS_POINTERS_BOOL ? kScratchRegister : no_reg;
  
    // Calling convention for function specific ConstructStubs require
    // rbx to contain either an AllocationSite or undefined.
    __ LoadRoot(rbx, RootIndex::kUndefinedValue);
  
    // Jump to JSBuiltinsConstructStub or JSConstructStubGeneric.
    __ LoadTaggedPointerField(
        rcx, FieldOperand(rdi, JSFunction::kSharedFunctionInfoOffset),
        decompr_scratch_for_debug);
    __ testl(FieldOperand(rcx, SharedFunctionInfo::kFlagsOffset),
             Immediate(SharedFunctionInfo::ConstructAsBuiltinBit::kMask));
    __ Jump(BUILTIN_CODE(masm->isolate(), JSBuiltinsConstructStub),
            RelocInfo::CODE_TARGET, not_zero);
  
    __ Jump(BUILTIN_CODE(masm->isolate(), JSConstructStubGeneric),
            RelocInfo::CODE_TARGET);
  }
  
  // static
  void Builtins::Generate_ConstructBoundFunction(MacroAssembler* masm) {
    // ----------- S t a t e -------------
    //  -- rax : the number of arguments (not including the receiver)
    //  -- rdx : the new target (checked to be a constructor)
    //  -- rdi : the constructor to call (checked to be a JSBoundFunction)
    // -----------------------------------
    __ AssertConstructor(rdi);
    __ AssertBoundFunction(rdi);
  
    Register decompr_scratch_for_debug =
        COMPRESS_POINTERS_BOOL ? kScratchRegister : no_reg;
  
    // Push the [[BoundArguments]] onto the stack.
    Generate_PushBoundArguments(masm);
  
    // Patch new.target to [[BoundTargetFunction]] if new.target equals target.
    {
      Label done;
      __ cmpq(rdi, rdx);
      __ j(not_equal, &done, Label::kNear);
      __ LoadTaggedPointerField(
          rdx, FieldOperand(rdi, JSBoundFunction::kBoundTargetFunctionOffset),
          decompr_scratch_for_debug);
      __ bind(&done);
    }
  
    // Construct the [[BoundTargetFunction]] via the Construct builtin.
    __ LoadTaggedPointerField(
        rdi, FieldOperand(rdi, JSBoundFunction::kBoundTargetFunctionOffset),
        decompr_scratch_for_debug);
    __ Jump(BUILTIN_CODE(masm->isolate(), Construct), RelocInfo::CODE_TARGET);
  }
  
  // static
  void Builtins::Generate_Construct(MacroAssembler* masm) {
    // ----------- S t a t e -------------
    //  -- rax : the number of arguments (not including the receiver)
    //  -- rdx : the new target (either the same as the constructor or
    //           the JSFunction on which new was invoked initially)
    //  -- rdi : the constructor to call (can be any Object)
    // -----------------------------------
    StackArgumentsAccessor args(rsp, rax);
  
    Register decompr_scratch_for_debug =
        COMPRESS_POINTERS_BOOL ? kScratchRegister : no_reg;
  
    // Check if target is a Smi.
    Label non_constructor;
    __ JumpIfSmi(rdi, &non_constructor);
  
    // Check if target has a [[Construct]] internal method.
    __ LoadTaggedPointerField(rcx, FieldOperand(rdi, HeapObject::kMapOffset),
                              decompr_scratch_for_debug);
    __ testb(FieldOperand(rcx, Map::kBitFieldOffset),
             Immediate(Map::IsConstructorBit::kMask));
    __ j(zero, &non_constructor);
  
    // Dispatch based on instance type.
    __ CmpInstanceType(rcx, JS_FUNCTION_TYPE);
    __ Jump(BUILTIN_CODE(masm->isolate(), ConstructFunction),
            RelocInfo::CODE_TARGET, equal);
  
    // Only dispatch to bound functions after checking whether they are
    // constructors.
    __ CmpInstanceType(rcx, JS_BOUND_FUNCTION_TYPE);
    __ Jump(BUILTIN_CODE(masm->isolate(), ConstructBoundFunction),
            RelocInfo::CODE_TARGET, equal);
  
    // Only dispatch to proxies after checking whether they are constructors.
    __ CmpInstanceType(rcx, JS_PROXY_TYPE);
    __ Jump(BUILTIN_CODE(masm->isolate(), ConstructProxy), RelocInfo::CODE_TARGET,
            equal);
  
    // Called Construct on an exotic Object with a [[Construct]] internal method.
    {
      // Overwrite the original receiver with the (original) target.
      __ movq(args.GetReceiverOperand(), rdi);
      // Let the "call_as_constructor_delegate" take care of the rest.
      __ LoadNativeContextSlot(Context::CALL_AS_CONSTRUCTOR_DELEGATE_INDEX, rdi);
      __ Jump(masm->isolate()->builtins()->CallFunction(),
              RelocInfo::CODE_TARGET);
    }
  
    // Called Construct on an Object that doesn't have a [[Construct]] internal
    // method.
    __ bind(&non_constructor);
    __ Jump(BUILTIN_CODE(masm->isolate(), ConstructedNonConstructable),
            RelocInfo::CODE_TARGET);
  }
  
  void Builtins::Generate_InterpreterOnStackReplacement(MacroAssembler* masm) {
    // Lookup the function in the JavaScript frame.
    __ movq(rax, Operand(rbp, StandardFrameConstants::kCallerFPOffset));
    __ movq(rax, Operand(rax, JavaScriptFrameConstants::kFunctionOffset));
  
    {
      FrameScope scope(masm, StackFrame::INTERNAL);
      // Pass function as argument.
      __ Push(rax);
      __ CallRuntime(Runtime::kCompileForOnStackReplacement);
    }
  
    Label skip;
    // If the code object is null, just return to the caller.
    __ testq(rax, rax);
    __ j(not_equal, &skip, Label::kNear);
    __ ret(0);
  
    __ bind(&skip);
  
    // Drop the handler frame that is be sitting on top of the actual
    // JavaScript frame. This is the case then OSR is triggered from bytecode.
    __ leave();
  
    // Load deoptimization data from the code object.
    __ LoadTaggedPointerField(rbx,
                              FieldOperand(rax, Code::kDeoptimizationDataOffset));
  
    // Load the OSR entrypoint offset from the deoptimization data.
    __ SmiUntagField(
        rbx, FieldOperand(rbx, FixedArray::OffsetOfElementAt(
                                   DeoptimizationData::kOsrPcOffsetIndex)));
  
    // Compute the target address = code_obj + header_size + osr_offset
    __ leaq(rax, FieldOperand(rax, rbx, times_1, Code::kHeaderSize));
  
    // Overwrite the return address on the stack.
    __ movq(StackOperandForReturnAddress(0), rax);
  
    // And "return" to the OSR entry point of the function.
    __ ret(0);
  }
  
  void Builtins::Generate_WasmCompileLazy(MacroAssembler* masm) {
    // The function index was pushed to the stack by the caller as int32.
    __ Pop(r11);
    // Convert to Smi for the runtime call.
    __ SmiTag(r11, r11);
    {
      HardAbortScope hard_abort(masm);  // Avoid calls to Abort.
      FrameScope scope(masm, StackFrame::WASM_COMPILE_LAZY);
  
      // Save all parameter registers (see wasm-linkage.cc). They might be
      // overwritten in the runtime call below. We don't have any callee-saved
      // registers in wasm, so no need to store anything else.
      static_assert(WasmCompileLazyFrameConstants::kNumberOfSavedGpParamRegs ==
                        arraysize(wasm::kGpParamRegisters),
                    "frame size mismatch");
      for (Register reg : wasm::kGpParamRegisters) {
        __ Push(reg);
      }
      static_assert(WasmCompileLazyFrameConstants::kNumberOfSavedFpParamRegs ==
                        arraysize(wasm::kFpParamRegisters),
                    "frame size mismatch");
      __ subq(rsp, Immediate(kSimd128Size * arraysize(wasm::kFpParamRegisters)));
      int offset = 0;
      for (DoubleRegister reg : wasm::kFpParamRegisters) {
        __ movdqu(Operand(rsp, offset), reg);
        offset += kSimd128Size;
      }
  
      // Push the WASM instance as an explicit argument to WasmCompileLazy.
      __ Push(kWasmInstanceRegister);
      // Push the function index as second argument.
      __ Push(r11);
      // Load the correct CEntry builtin from the instance object.
      Register decompr_scratch_for_debug =
          COMPRESS_POINTERS_BOOL ? kScratchRegister : no_reg;
      __ LoadTaggedPointerField(
          rcx,
          FieldOperand(kWasmInstanceRegister,
                       WasmInstanceObject::kCEntryStubOffset),
          decompr_scratch_for_debug);
      // Initialize the JavaScript context with 0. CEntry will use it to
      // set the current context on the isolate.
      __ Move(kContextRegister, Smi::zero());
      __ CallRuntimeWithCEntry(Runtime::kWasmCompileLazy, rcx);
      // The entrypoint address is the return value.
      __ movq(r11, kReturnRegister0);
  
      // Restore registers.
      for (DoubleRegister reg : base::Reversed(wasm::kFpParamRegisters)) {
        offset -= kSimd128Size;
        __ movdqu(reg, Operand(rsp, offset));
      }
      DCHECK_EQ(0, offset);
      __ addq(rsp, Immediate(kSimd128Size * arraysize(wasm::kFpParamRegisters)));
      for (Register reg : base::Reversed(wasm::kGpParamRegisters)) {
        __ Pop(reg);
      }
    }
    // Finally, jump to the entrypoint.
    __ jmp(r11);
  }
  
  void Builtins::Generate_CEntry(MacroAssembler* masm, int result_size,
                                 SaveFPRegsMode save_doubles, ArgvMode argv_mode,
                                 bool builtin_exit_frame) {
    // rax: number of arguments including receiver
    // rbx: pointer to C function  (C callee-saved)
    // rbp: frame pointer of calling JS frame (restored after C call)
    // rsp: stack pointer  (restored after C call)
    // rsi: current context (restored)
    //
    // If argv_mode == kArgvInRegister:
    // r15: pointer to the first argument
  
  #ifdef _WIN64
    // Windows 64-bit ABI passes arguments in rcx, rdx, r8, r9. It requires the
    // stack to be aligned to 16 bytes. It only allows a single-word to be
    // returned in register rax. Larger return sizes must be written to an address
    // passed as a hidden first argument.
    const Register kCCallArg0 = rcx;
    const Register kCCallArg1 = rdx;
    const Register kCCallArg2 = r8;
    const Register kCCallArg3 = r9;
    const int kArgExtraStackSpace = 2;
    const int kMaxRegisterResultSize = 1;
  #else
    // GCC / Clang passes arguments in rdi, rsi, rdx, rcx, r8, r9. Simple results
    // are returned in rax, and a struct of two pointers are returned in rax+rdx.
    // Larger return sizes must be written to an address passed as a hidden first
    // argument.
    const Register kCCallArg0 = rdi;
    const Register kCCallArg1 = rsi;
    const Register kCCallArg2 = rdx;
    const Register kCCallArg3 = rcx;
    const int kArgExtraStackSpace = 0;
    const int kMaxRegisterResultSize = 2;
  #endif  // _WIN64
  
    // Enter the exit frame that transitions from JavaScript to C++.
    int arg_stack_space =
        kArgExtraStackSpace +
        (result_size <= kMaxRegisterResultSize ? 0 : result_size);
    if (argv_mode == kArgvInRegister) {
      DCHECK(save_doubles == kDontSaveFPRegs);
      DCHECK(!builtin_exit_frame);
      __ EnterApiExitFrame(arg_stack_space);
      // Move argc into r14 (argv is already in r15).
      __ movq(r14, rax);
    } else {
      __ EnterExitFrame(
          arg_stack_space, save_doubles == kSaveFPRegs,
          builtin_exit_frame ? StackFrame::BUILTIN_EXIT : StackFrame::EXIT);
    }
  
    // rbx: pointer to builtin function  (C callee-saved).
    // rbp: frame pointer of exit frame  (restored after C call).
    // rsp: stack pointer (restored after C call).
    // r14: number of arguments including receiver (C callee-saved).
    // r15: argv pointer (C callee-saved).
  
    // Check stack alignment.
    if (FLAG_debug_code) {
      __ CheckStackAlignment();
    }
  
    // Call C function. The arguments object will be created by stubs declared by
    // DECLARE_RUNTIME_FUNCTION().
    if (result_size <= kMaxRegisterResultSize) {
      // Pass a pointer to the Arguments object as the first argument.
      // Return result in single register (rax), or a register pair (rax, rdx).
      __ movq(kCCallArg0, r14);  // argc.
      __ movq(kCCallArg1, r15);  // argv.
      __ Move(kCCallArg2, ExternalReference::isolate_address(masm->isolate()));
    } else {
      DCHECK_LE(result_size, 2);
      // Pass a pointer to the result location as the first argument.
      __ leaq(kCCallArg0, StackSpaceOperand(kArgExtraStackSpace));
      // Pass a pointer to the Arguments object as the second argument.
      __ movq(kCCallArg1, r14);  // argc.
      __ movq(kCCallArg2, r15);  // argv.
      __ Move(kCCallArg3, ExternalReference::isolate_address(masm->isolate()));
    }
    __ call(rbx);
  
    if (result_size > kMaxRegisterResultSize) {
      // Read result values stored on stack. Result is stored
      // above the the two Arguments object slots on Win64.
      DCHECK_LE(result_size, 2);
      __ movq(kReturnRegister0, StackSpaceOperand(kArgExtraStackSpace + 0));
      __ movq(kReturnRegister1, StackSpaceOperand(kArgExtraStackSpace + 1));
    }
    // Result is in rax or rdx:rax - do not destroy these registers!
  
    // Check result for exception sentinel.
    Label exception_returned;
    __ CompareRoot(rax, RootIndex::kException);
    __ j(equal, &exception_returned);
  
    // Check that there is no pending exception, otherwise we
    // should have returned the exception sentinel.
    if (FLAG_debug_code) {
      Label okay;
      __ LoadRoot(r14, RootIndex::kTheHoleValue);
      ExternalReference pending_exception_address = ExternalReference::Create(
          IsolateAddressId::kPendingExceptionAddress, masm->isolate());
      Operand pending_exception_operand =
          masm->ExternalReferenceAsOperand(pending_exception_address);
      __ cmpq(r14, pending_exception_operand);
      __ j(equal, &okay, Label::kNear);
      __ int3();
      __ bind(&okay);
    }
  
    // Exit the JavaScript to C++ exit frame.
    __ LeaveExitFrame(save_doubles == kSaveFPRegs, argv_mode == kArgvOnStack);
    __ ret(0);
  
    // Handling of exception.
    __ bind(&exception_returned);
  
    ExternalReference pending_handler_context_address = ExternalReference::Create(
        IsolateAddressId::kPendingHandlerContextAddress, masm->isolate());
    ExternalReference pending_handler_entrypoint_address =
        ExternalReference::Create(
            IsolateAddressId::kPendingHandlerEntrypointAddress, masm->isolate());
    ExternalReference pending_handler_fp_address = ExternalReference::Create(
        IsolateAddressId::kPendingHandlerFPAddress, masm->isolate());
    ExternalReference pending_handler_sp_address = ExternalReference::Create(
        IsolateAddressId::kPendingHandlerSPAddress, masm->isolate());
  
    // Ask the runtime for help to determine the handler. This will set rax to
    // contain the current pending exception, don't clobber it.
    ExternalReference find_handler =
        ExternalReference::Create(Runtime::kUnwindAndFindExceptionHandler);
    {
      FrameScope scope(masm, StackFrame::MANUAL);
      __ movq(arg_reg_1, Immediate(0));  // argc.
      __ movq(arg_reg_2, Immediate(0));  // argv.
      __ Move(arg_reg_3, ExternalReference::isolate_address(masm->isolate()));
      __ PrepareCallCFunction(3);
      __ CallCFunction(find_handler, 3);
    }
    // Retrieve the handler context, SP and FP.
    __ movq(rsi,
            masm->ExternalReferenceAsOperand(pending_handler_context_address));
    __ movq(rsp, masm->ExternalReferenceAsOperand(pending_handler_sp_address));
    __ movq(rbp, masm->ExternalReferenceAsOperand(pending_handler_fp_address));
  
    // If the handler is a JS frame, restore the context to the frame. Note that
    // the context will be set to (rsi == 0) for non-JS frames.
    Label skip;
    __ testq(rsi, rsi);
    __ j(zero, &skip, Label::kNear);
    __ movq(Operand(rbp, StandardFrameConstants::kContextOffset), rsi);
    __ bind(&skip);
  
    // Reset the masking register. This is done independent of the underlying
    // feature flag {FLAG_untrusted_code_mitigations} to make the snapshot work
    // with both configurations. It is safe to always do this, because the
    // underlying register is caller-saved and can be arbitrarily clobbered.
    __ ResetSpeculationPoisonRegister();
  
    // Compute the handler entry address and jump to it.
    __ movq(rdi,
            masm->ExternalReferenceAsOperand(pending_handler_entrypoint_address));
    __ jmp(rdi);
  }
  
  void Builtins::Generate_DoubleToI(MacroAssembler* masm) {
    Label check_negative, process_64_bits, done;
  
    // Account for return address and saved regs.
    const int kArgumentOffset = 4 * kSystemPointerSize;
  
    MemOperand mantissa_operand(MemOperand(rsp, kArgumentOffset));
    MemOperand exponent_operand(
        MemOperand(rsp, kArgumentOffset + kDoubleSize / 2));
  
    // The result is returned on the stack.
    MemOperand return_operand = mantissa_operand;
  
    Register scratch1 = rbx;
  
    // Since we must use rcx for shifts below, use some other register (rax)
    // to calculate the result if ecx is the requested return register.
    Register result_reg = rax;
    // Save ecx if it isn't the return register and therefore volatile, or if it
    // is the return register, then save the temp register we use in its stead
    // for the result.
    Register save_reg = rax;
    __ pushq(rcx);
    __ pushq(scratch1);
    __ pushq(save_reg);
  
    __ movl(scratch1, mantissa_operand);
    __ Movsd(kScratchDoubleReg, mantissa_operand);
    __ movl(rcx, exponent_operand);
  
    __ andl(rcx, Immediate(HeapNumber::kExponentMask));
    __ shrl(rcx, Immediate(HeapNumber::kExponentShift));
    __ leal(result_reg, MemOperand(rcx, -HeapNumber::kExponentBias));
    __ cmpl(result_reg, Immediate(HeapNumber::kMantissaBits));
    __ j(below, &process_64_bits, Label::kNear);
  
    // Result is entirely in lower 32-bits of mantissa
    int delta = HeapNumber::kExponentBias + Double::kPhysicalSignificandSize;
    __ subl(rcx, Immediate(delta));
    __ xorl(result_reg, result_reg);
    __ cmpl(rcx, Immediate(31));
    __ j(above, &done, Label::kNear);
    __ shll_cl(scratch1);
    __ jmp(&check_negative, Label::kNear);
  
    __ bind(&process_64_bits);
    __ Cvttsd2siq(result_reg, kScratchDoubleReg);
    __ jmp(&done, Label::kNear);
  
    // If the double was negative, negate the integer result.
    __ bind(&check_negative);
    __ movl(result_reg, scratch1);
    __ negl(result_reg);
    __ cmpl(exponent_operand, Immediate(0));
    __ cmovl(greater, result_reg, scratch1);
  
    // Restore registers
    __ bind(&done);
    __ movl(return_operand, result_reg);
    __ popq(save_reg);
    __ popq(scratch1);
    __ popq(rcx);
    __ ret(0);
  }
  
  void Builtins::Generate_MathPowInternal(MacroAssembler* masm) {
    const Register exponent = rdx;
    const Register scratch = rcx;
    const XMMRegister double_result = xmm3;
    const XMMRegister double_base = xmm2;
    const XMMRegister double_exponent = xmm1;
    const XMMRegister double_scratch = xmm4;
  
    Label call_runtime, done, int_exponent;
  
    // Save 1 in double_result - we need this several times later on.
    __ movq(scratch, Immediate(1));
    __ Cvtlsi2sd(double_result, scratch);
  
    Label fast_power, try_arithmetic_simplification;
    // Detect integer exponents stored as double.
    __ DoubleToI(exponent, double_exponent, double_scratch,
                 &try_arithmetic_simplification, &try_arithmetic_simplification);
    __ jmp(&int_exponent);
  
    __ bind(&try_arithmetic_simplification);
    __ Cvttsd2si(exponent, double_exponent);
    // Skip to runtime if possibly NaN (indicated by the indefinite integer).
    __ cmpl(exponent, Immediate(0x1));
    __ j(overflow, &call_runtime);
  
    // Using FPU instructions to calculate power.
    Label fast_power_failed;
    __ bind(&fast_power);
    __ fnclex();  // Clear flags to catch exceptions later.
    // Transfer (B)ase and (E)xponent onto the FPU register stack.
    __ subq(rsp, Immediate(kDoubleSize));
    __ Movsd(Operand(rsp, 0), double_exponent);
    __ fld_d(Operand(rsp, 0));  // E
    __ Movsd(Operand(rsp, 0), double_base);
    __ fld_d(Operand(rsp, 0));  // B, E
  
    // Exponent is in st(1) and base is in st(0)
    // B ^ E = (2^(E * log2(B)) - 1) + 1 = (2^X - 1) + 1 for X = E * log2(B)
    // FYL2X calculates st(1) * log2(st(0))
    __ fyl2x();    // X
    __ fld(0);     // X, X
    __ frndint();  // rnd(X), X
    __ fsub(1);    // rnd(X), X-rnd(X)
    __ fxch(1);    // X - rnd(X), rnd(X)
    // F2XM1 calculates 2^st(0) - 1 for -1 < st(0) < 1
    __ f2xm1();   // 2^(X-rnd(X)) - 1, rnd(X)
    __ fld1();    // 1, 2^(X-rnd(X)) - 1, rnd(X)
    __ faddp(1);  // 2^(X-rnd(X)), rnd(X)
    // FSCALE calculates st(0) * 2^st(1)
    __ fscale();  // 2^X, rnd(X)
    __ fstp(1);
    // Bail out to runtime in case of exceptions in the status word.
    __ fnstsw_ax();
    __ testb(rax, Immediate(0x5F));  // Check for all but precision exception.
    __ j(not_zero, &fast_power_failed, Label::kNear);
    __ fstp_d(Operand(rsp, 0));
    __ Movsd(double_result, Operand(rsp, 0));
    __ addq(rsp, Immediate(kDoubleSize));
    __ jmp(&done);
  
    __ bind(&fast_power_failed);
    __ fninit();
    __ addq(rsp, Immediate(kDoubleSize));
    __ jmp(&call_runtime);
  
    // Calculate power with integer exponent.
    __ bind(&int_exponent);
    const XMMRegister double_scratch2 = double_exponent;
    // Back up exponent as we need to check if exponent is negative later.
    __ movq(scratch, exponent);                // Back up exponent.
    __ Movsd(double_scratch, double_base);     // Back up base.
    __ Movsd(double_scratch2, double_result);  // Load double_exponent with 1.
  
    // Get absolute value of exponent.
    Label no_neg, while_true, while_false;
    __ testl(scratch, scratch);
    __ j(positive, &no_neg, Label::kNear);
    __ negl(scratch);
    __ bind(&no_neg);
  
    __ j(zero, &while_false, Label::kNear);
    __ shrl(scratch, Immediate(1));
    // Above condition means CF==0 && ZF==0.  This means that the
    // bit that has been shifted out is 0 and the result is not 0.
    __ j(above, &while_true, Label::kNear);
    __ Movsd(double_result, double_scratch);
    __ j(zero, &while_false, Label::kNear);
  
    __ bind(&while_true);
    __ shrl(scratch, Immediate(1));
    __ Mulsd(double_scratch, double_scratch);
    __ j(above, &while_true, Label::kNear);
    __ Mulsd(double_result, double_scratch);
    __ j(not_zero, &while_true);
  
    __ bind(&while_false);
    // If the exponent is negative, return 1/result.
    __ testl(exponent, exponent);
    __ j(greater, &done);
    __ Divsd(double_scratch2, double_result);
    __ Movsd(double_result, double_scratch2);
    // Test whether result is zero.  Bail out to check for subnormal result.
    // Due to subnormals, x^-y == (1/x)^y does not hold in all cases.
    __ Xorpd(double_scratch2, double_scratch2);
    __ Ucomisd(double_scratch2, double_result);
    // double_exponent aliased as double_scratch2 has already been overwritten
    // and may not have contained the exponent value in the first place when the
    // input was a smi.  We reset it with exponent value before bailing out.
    __ j(not_equal, &done);
    __ Cvtlsi2sd(double_exponent, exponent);
  
    // Returning or bailing out.
    __ bind(&call_runtime);
    // Move base to the correct argument register.  Exponent is already in xmm1.
    __ Movsd(xmm0, double_base);
    DCHECK(double_exponent == xmm1);
    {
      AllowExternalCallThatCantCauseGC scope(masm);
      __ PrepareCallCFunction(2);
      __ CallCFunction(ExternalReference::power_double_double_function(), 2);
    }
    // Return value is in xmm0.
    __ Movsd(double_result, xmm0);
  
    __ bind(&done);
    __ ret(0);
  }
  
  void Builtins::Generate_InternalArrayConstructorImpl(MacroAssembler* masm) {
    // ----------- S t a t e -------------
    //  -- rax    : argc
    //  -- rdi    : constructor
    //  -- rsp[0] : return address
    //  -- rsp[8] : last argument
    // -----------------------------------
  
    Register decompr_scratch_for_debug =
        COMPRESS_POINTERS_BOOL ? kScratchRegister : no_reg;
  
    if (FLAG_debug_code) {
      // The array construct code is only set for the global and natives
      // builtin Array functions which always have maps.
  
      // Initial map for the builtin Array function should be a map.
      __ LoadTaggedPointerField(
          rcx, FieldOperand(rdi, JSFunction::kPrototypeOrInitialMapOffset),
          decompr_scratch_for_debug);
      // Will both indicate a nullptr and a Smi.
      STATIC_ASSERT(kSmiTag == 0);
      Condition not_smi = NegateCondition(masm->CheckSmi(rcx));
      __ Check(not_smi, AbortReason::kUnexpectedInitialMapForArrayFunction);
      __ CmpObjectType(rcx, MAP_TYPE, rcx);
      __ Check(equal, AbortReason::kUnexpectedInitialMapForArrayFunction);
  
      // Figure out the right elements kind
      __ LoadTaggedPointerField(
          rcx, FieldOperand(rdi, JSFunction::kPrototypeOrInitialMapOffset),
          decompr_scratch_for_debug);
  
      // Load the map's "bit field 2" into |result|. We only need the first byte,
      // but the following masking takes care of that anyway.
      __ movzxbq(rcx, FieldOperand(rcx, Map::kBitField2Offset));
      // Retrieve elements_kind from bit field 2.
      __ DecodeField<Map::ElementsKindBits>(rcx);
  
      // Initial elements kind should be packed elements.
      __ cmpl(rcx, Immediate(PACKED_ELEMENTS));
      __ Assert(equal, AbortReason::kInvalidElementsKindForInternalPackedArray);
  
      // No arguments should be passed.
      __ testq(rax, rax);
      __ Assert(zero, AbortReason::kWrongNumberOfArgumentsForInternalPackedArray);
    }
  
    __ Jump(
        BUILTIN_CODE(masm->isolate(), InternalArrayNoArgumentConstructor_Packed),
        RelocInfo::CODE_TARGET);
  }
  
  namespace {
  
  int Offset(ExternalReference ref0, ExternalReference ref1) {
    int64_t offset = (ref0.address() - ref1.address());
    // Check that fits into int.
    DCHECK(static_cast<int>(offset) == offset);
    return static_cast<int>(offset);
  }
  
  // Calls an API function.  Allocates HandleScope, extracts returned value
  // from handle and propagates exceptions.  Clobbers r14, r15, rbx and
  // caller-save registers.  Restores context.  On return removes
  // stack_space * kSystemPointerSize (GCed).
  void CallApiFunctionAndReturn(MacroAssembler* masm, Register function_address,
                                ExternalReference thunk_ref,
                                Register thunk_last_arg, int stack_space,
                                Operand* stack_space_operand,
                                Operand return_value_operand) {
    Label prologue;
    Label promote_scheduled_exception;
    Label delete_allocated_handles;
    Label leave_exit_frame;
  
    Isolate* isolate = masm->isolate();
    Factory* factory = isolate->factory();
    ExternalReference next_address =
        ExternalReference::handle_scope_next_address(isolate);
    const int kNextOffset = 0;
    const int kLimitOffset = Offset(
        ExternalReference::handle_scope_limit_address(isolate), next_address);
    const int kLevelOffset = Offset(
        ExternalReference::handle_scope_level_address(isolate), next_address);
    ExternalReference scheduled_exception_address =
        ExternalReference::scheduled_exception_address(isolate);
  
    DCHECK(rdx == function_address || r8 == function_address);
    // Allocate HandleScope in callee-save registers.
    Register prev_next_address_reg = r14;
    Register prev_limit_reg = rbx;
    Register base_reg = r15;
    __ Move(base_reg, next_address);
    __ movq(prev_next_address_reg, Operand(base_reg, kNextOffset));
    __ movq(prev_limit_reg, Operand(base_reg, kLimitOffset));
    __ addl(Operand(base_reg, kLevelOffset), Immediate(1));
  
    if (FLAG_log_timer_events) {
      FrameScope frame(masm, StackFrame::MANUAL);
      __ PushSafepointRegisters();
      __ PrepareCallCFunction(1);
      __ LoadAddress(arg_reg_1, ExternalReference::isolate_address(isolate));
      __ CallCFunction(ExternalReference::log_enter_external_function(), 1);
      __ PopSafepointRegisters();
    }
  
    Label profiler_disabled;
    Label end_profiler_check;
    __ Move(rax, ExternalReference::is_profiling_address(isolate));
    __ cmpb(Operand(rax, 0), Immediate(0));
    __ j(zero, &profiler_disabled);
  
    // Third parameter is the address of the actual getter function.
    __ Move(thunk_last_arg, function_address);
    __ Move(rax, thunk_ref);
    __ jmp(&end_profiler_check);
  
    __ bind(&profiler_disabled);
    // Call the api function!
    __ Move(rax, function_address);
  
    __ bind(&end_profiler_check);
  
    // Call the api function!
    __ call(rax);
  
    if (FLAG_log_timer_events) {
      FrameScope frame(masm, StackFrame::MANUAL);
      __ PushSafepointRegisters();
      __ PrepareCallCFunction(1);
      __ LoadAddress(arg_reg_1, ExternalReference::isolate_address(isolate));
      __ CallCFunction(ExternalReference::log_leave_external_function(), 1);
      __ PopSafepointRegisters();
    }
  
    // Load the value from ReturnValue
    __ movq(rax, return_value_operand);
    __ bind(&prologue);
  
    // No more valid handles (the result handle was the last one). Restore
    // previous handle scope.
    __ subl(Operand(base_reg, kLevelOffset), Immediate(1));
    __ movq(Operand(base_reg, kNextOffset), prev_next_address_reg);
    __ cmpq(prev_limit_reg, Operand(base_reg, kLimitOffset));
    __ j(not_equal, &delete_allocated_handles);
  
    // Leave the API exit frame.
    __ bind(&leave_exit_frame);
    if (stack_space_operand != nullptr) {
      DCHECK_EQ(stack_space, 0);
      __ movq(rbx, *stack_space_operand);
    }
    __ LeaveApiExitFrame();
  
    // Check if the function scheduled an exception.
    __ Move(rdi, scheduled_exception_address);
    __ Cmp(Operand(rdi, 0), factory->the_hole_value());
    __ j(not_equal, &promote_scheduled_exception);
  
  #if DEBUG
    // Check if the function returned a valid JavaScript value.
    Label ok;
    Register return_value = rax;
    Register map = rcx;
  
    __ JumpIfSmi(return_value, &ok, Label::kNear);
    Register decompr_scratch_for_debug =
        COMPRESS_POINTERS_BOOL ? kScratchRegister : no_reg;
    __ LoadTaggedPointerField(map,
                              FieldOperand(return_value, HeapObject::kMapOffset),
                              decompr_scratch_for_debug);
  
    __ CmpInstanceType(map, LAST_NAME_TYPE);
    __ j(below_equal, &ok, Label::kNear);
  
    __ CmpInstanceType(map, FIRST_JS_RECEIVER_TYPE);
    __ j(above_equal, &ok, Label::kNear);
  
    __ CompareRoot(map, RootIndex::kHeapNumberMap);
    __ j(equal, &ok, Label::kNear);
  
    __ CompareRoot(return_value, RootIndex::kUndefinedValue);
    __ j(equal, &ok, Label::kNear);
  
    __ CompareRoot(return_value, RootIndex::kTrueValue);
    __ j(equal, &ok, Label::kNear);
  
    __ CompareRoot(return_value, RootIndex::kFalseValue);
    __ j(equal, &ok, Label::kNear);
  
    __ CompareRoot(return_value, RootIndex::kNullValue);
    __ j(equal, &ok, Label::kNear);
  
    __ Abort(AbortReason::kAPICallReturnedInvalidObject);
  
    __ bind(&ok);
  #endif
  
    if (stack_space_operand == nullptr) {
      DCHECK_NE(stack_space, 0);
      __ ret(stack_space * kSystemPointerSize);
    } else {
      DCHECK_EQ(stack_space, 0);
      __ PopReturnAddressTo(rcx);
      __ addq(rsp, rbx);
      __ jmp(rcx);
    }
  
    // Re-throw by promoting a scheduled exception.
    __ bind(&promote_scheduled_exception);
    __ TailCallRuntime(Runtime::kPromoteScheduledException);
  
    // HandleScope limit has changed. Delete allocated extensions.
    __ bind(&delete_allocated_handles);
    __ movq(Operand(base_reg, kLimitOffset), prev_limit_reg);
    __ movq(prev_limit_reg, rax);
    __ LoadAddress(arg_reg_1, ExternalReference::isolate_address(isolate));
    __ LoadAddress(rax, ExternalReference::delete_handle_scope_extensions());
    __ call(rax);
    __ movq(rax, prev_limit_reg);
    __ jmp(&leave_exit_frame);
  }
  
  }  // namespace
  
  // TODO(jgruber): Instead of explicitly setting up implicit_args_ on the stack
  // in CallApiCallback, we could use the calling convention to set up the stack
  // correctly in the first place.
  //
  // TODO(jgruber): I suspect that most of CallApiCallback could be implemented
  // as a C++ trampoline, vastly simplifying the assembly implementation.
  
  void Builtins::Generate_CallApiCallback(MacroAssembler* masm) {
    // ----------- S t a t e -------------
    //  -- rsi                 : kTargetContext
    //  -- rdx                 : kApiFunctionAddress
    //  -- rcx                 : kArgc
    //  --
    //  -- rsp[0]              : return address
    //  -- rsp[8]              : last argument
    //  -- ...
    //  -- rsp[argc * 8]       : first argument
    //  -- rsp[(argc + 1) * 8] : receiver
    //  -- rsp[(argc + 2) * 8] : kHolder
    //  -- rsp[(argc + 3) * 8] : kCallData
    // -----------------------------------
  
    Register api_function_address = rdx;
    Register argc = rcx;
  
    DCHECK(!AreAliased(api_function_address, argc, kScratchRegister));
  
    // Stack offsets (without argc).
    static constexpr int kReceiverOffset = kSystemPointerSize;
    static constexpr int kHolderOffset = kReceiverOffset + kSystemPointerSize;
    static constexpr int kCallDataOffset = kHolderOffset + kSystemPointerSize;
  
    // Extra stack arguments are: the receiver, kHolder, kCallData.
    static constexpr int kExtraStackArgumentCount = 3;
  
    typedef FunctionCallbackArguments FCA;
  
    STATIC_ASSERT(FCA::kArgsLength == 6);
    STATIC_ASSERT(FCA::kNewTargetIndex == 5);
    STATIC_ASSERT(FCA::kDataIndex == 4);
    STATIC_ASSERT(FCA::kReturnValueOffset == 3);
    STATIC_ASSERT(FCA::kReturnValueDefaultValueIndex == 2);
    STATIC_ASSERT(FCA::kIsolateIndex == 1);
    STATIC_ASSERT(FCA::kHolderIndex == 0);
  
    // Set up FunctionCallbackInfo's implicit_args on the stack as follows:
    //
    // Current state:
    //   rsp[0]: return address
    //
    // Target state:
    //   rsp[0 * kSystemPointerSize]: return address
    //   rsp[1 * kSystemPointerSize]: kHolder
    //   rsp[2 * kSystemPointerSize]: kIsolate
    //   rsp[3 * kSystemPointerSize]: undefined (kReturnValueDefaultValue)
    //   rsp[4 * kSystemPointerSize]: undefined (kReturnValue)
    //   rsp[5 * kSystemPointerSize]: kData
    //   rsp[6 * kSystemPointerSize]: undefined (kNewTarget)
  
    // Reserve space on the stack.
    __ subq(rsp, Immediate(FCA::kArgsLength * kSystemPointerSize));
  
    // Return address (the old stack location is overwritten later on).
    __ movq(kScratchRegister,
            Operand(rsp, FCA::kArgsLength * kSystemPointerSize));
    __ movq(Operand(rsp, 0 * kSystemPointerSize), kScratchRegister);
  
    // kHolder.
    __ movq(kScratchRegister,
            Operand(rsp, argc, times_pointer_size,
                    FCA::kArgsLength * kSystemPointerSize + kHolderOffset));
    __ movq(Operand(rsp, 1 * kSystemPointerSize), kScratchRegister);
  
    // kIsolate.
    __ Move(kScratchRegister,
            ExternalReference::isolate_address(masm->isolate()));
    __ movq(Operand(rsp, 2 * kSystemPointerSize), kScratchRegister);
  
    // kReturnValueDefaultValue, kReturnValue, and kNewTarget.
    __ LoadRoot(kScratchRegister, RootIndex::kUndefinedValue);
    __ movq(Operand(rsp, 3 * kSystemPointerSize), kScratchRegister);
    __ movq(Operand(rsp, 4 * kSystemPointerSize), kScratchRegister);
    __ movq(Operand(rsp, 6 * kSystemPointerSize), kScratchRegister);
  
    // kData.
    __ movq(kScratchRegister,
            Operand(rsp, argc, times_pointer_size,
                    FCA::kArgsLength * kSystemPointerSize + kCallDataOffset));
    __ movq(Operand(rsp, 5 * kSystemPointerSize), kScratchRegister);
  
    // Keep a pointer to kHolder (= implicit_args) in a scratch register.
    // We use it below to set up the FunctionCallbackInfo object.
    Register scratch = rbx;
    __ leaq(scratch, Operand(rsp, 1 * kSystemPointerSize));
  
    // Allocate the v8::Arguments structure in the arguments' space since
    // it's not controlled by GC.
    static constexpr int kApiStackSpace = 4;
    __ EnterApiExitFrame(kApiStackSpace);
  
    // FunctionCallbackInfo::implicit_args_ (points at kHolder as set up above).
    __ movq(StackSpaceOperand(0), scratch);
  
    // FunctionCallbackInfo::values_ (points at the first varargs argument passed
    // on the stack).
    __ leaq(scratch, Operand(scratch, argc, times_pointer_size,
                             (FCA::kArgsLength - 1) * kSystemPointerSize));
    __ movq(StackSpaceOperand(1), scratch);
  
    // FunctionCallbackInfo::length_.
    __ movq(StackSpaceOperand(2), argc);
  
    // We also store the number of bytes to drop from the stack after returning
    // from the API function here.
    __ leaq(kScratchRegister,
            Operand(argc, times_pointer_size,
                    (FCA::kArgsLength + kExtraStackArgumentCount) *
                        kSystemPointerSize));
    __ movq(StackSpaceOperand(3), kScratchRegister);
  
    Register arguments_arg = arg_reg_1;
    Register callback_arg = arg_reg_2;
  
    // It's okay if api_function_address == callback_arg
    // but not arguments_arg
    DCHECK(api_function_address != arguments_arg);
  
    // v8::InvocationCallback's argument.
    __ leaq(arguments_arg, StackSpaceOperand(0));
  
    ExternalReference thunk_ref = ExternalReference::invoke_function_callback();
  
    // There are two stack slots above the arguments we constructed on the stack:
    // the stored ebp (pushed by EnterApiExitFrame), and the return address.
    static constexpr int kStackSlotsAboveFCA = 2;
    Operand return_value_operand(
        rbp,
        (kStackSlotsAboveFCA + FCA::kReturnValueOffset) * kSystemPointerSize);
  
    static constexpr int kUseStackSpaceOperand = 0;
    Operand stack_space_operand = StackSpaceOperand(3);
    CallApiFunctionAndReturn(masm, api_function_address, thunk_ref, callback_arg,
                             kUseStackSpaceOperand, &stack_space_operand,
                             return_value_operand);
  }
  
  void Builtins::Generate_CallApiGetter(MacroAssembler* masm) {
    Register name_arg = arg_reg_1;
    Register accessor_info_arg = arg_reg_2;
    Register getter_arg = arg_reg_3;
    Register api_function_address = r8;
    Register receiver = ApiGetterDescriptor::ReceiverRegister();
    Register holder = ApiGetterDescriptor::HolderRegister();
    Register callback = ApiGetterDescriptor::CallbackRegister();
    Register scratch = rax;
    Register decompr_scratch1 = COMPRESS_POINTERS_BOOL ? r11 : no_reg;
    Register decompr_scratch2 = COMPRESS_POINTERS_BOOL ? r12 : no_reg;
    Register decompr_scratch_for_debug =
        COMPRESS_POINTERS_BOOL ? kScratchRegister : no_reg;
  
    DCHECK(!AreAliased(receiver, holder, callback, scratch, decompr_scratch1,
                       decompr_scratch2, decompr_scratch_for_debug));
  
    // Build v8::PropertyCallbackInfo::args_ array on the stack and push property
    // name below the exit frame to make GC aware of them.
    STATIC_ASSERT(PropertyCallbackArguments::kShouldThrowOnErrorIndex == 0);
    STATIC_ASSERT(PropertyCallbackArguments::kHolderIndex == 1);
    STATIC_ASSERT(PropertyCallbackArguments::kIsolateIndex == 2);
    STATIC_ASSERT(PropertyCallbackArguments::kReturnValueDefaultValueIndex == 3);
    STATIC_ASSERT(PropertyCallbackArguments::kReturnValueOffset == 4);
    STATIC_ASSERT(PropertyCallbackArguments::kDataIndex == 5);
    STATIC_ASSERT(PropertyCallbackArguments::kThisIndex == 6);
    STATIC_ASSERT(PropertyCallbackArguments::kArgsLength == 7);
  
    // Insert additional parameters into the stack frame above return address.
    __ PopReturnAddressTo(scratch);
    __ Push(receiver);
    __ PushTaggedAnyField(FieldOperand(callback, AccessorInfo::kDataOffset),
                          decompr_scratch1, decompr_scratch2,
                          decompr_scratch_for_debug);
    __ LoadRoot(kScratchRegister, RootIndex::kUndefinedValue);
    __ Push(kScratchRegister);  // return value
    __ Push(kScratchRegister);  // return value default
    __ PushAddress(ExternalReference::isolate_address(masm->isolate()));
    __ Push(holder);
    __ Push(Smi::zero());  // should_throw_on_error -> false
    __ PushTaggedPointerField(FieldOperand(callback, AccessorInfo::kNameOffset),
                              decompr_scratch1, decompr_scratch_for_debug);
    __ PushReturnAddressFrom(scratch);
  
    // v8::PropertyCallbackInfo::args_ array and name handle.
    const int kStackUnwindSpace = PropertyCallbackArguments::kArgsLength + 1;
  
    // Allocate v8::PropertyCallbackInfo in non-GCed stack space.
    const int kArgStackSpace = 1;
  
    // Load address of v8::PropertyAccessorInfo::args_ array.
    __ leaq(scratch, Operand(rsp, 2 * kSystemPointerSize));
  
    __ EnterApiExitFrame(kArgStackSpace);
  
    // Create v8::PropertyCallbackInfo object on the stack and initialize
    // it's args_ field.
    Operand info_object = StackSpaceOperand(0);
    __ movq(info_object, scratch);
  
    __ leaq(name_arg, Operand(scratch, -kSystemPointerSize));
    // The context register (rsi) has been saved in EnterApiExitFrame and
    // could be used to pass arguments.
    __ leaq(accessor_info_arg, info_object);
  
    ExternalReference thunk_ref =
        ExternalReference::invoke_accessor_getter_callback();
  
    // It's okay if api_function_address == getter_arg
    // but not accessor_info_arg or name_arg
    DCHECK(api_function_address != accessor_info_arg);
    DCHECK(api_function_address != name_arg);
    __ LoadTaggedPointerField(
        scratch, FieldOperand(callback, AccessorInfo::kJsGetterOffset),
        decompr_scratch_for_debug);
    __ movq(api_function_address,
            FieldOperand(scratch, Foreign::kForeignAddressOffset));
  
    // +3 is to skip prolog, return address and name handle.
    Operand return_value_operand(
        rbp,
        (PropertyCallbackArguments::kReturnValueOffset + 3) * kSystemPointerSize);
    Operand* const kUseStackSpaceConstant = nullptr;
    CallApiFunctionAndReturn(masm, api_function_address, thunk_ref, getter_arg,
                             kStackUnwindSpace, kUseStackSpaceConstant,
                             return_value_operand);
  }
  
  void Builtins::Generate_DirectCEntry(MacroAssembler* masm) {
    __ int3();  // Unused on this architecture.
  }
  
  #undef __
  
  }  // namespace internal
  }  // namespace v8
  
  #endif  // V8_TARGET_ARCH_X64
  