builtins-riscv.cc

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// Copyright 2021 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.
 
#include "src/api/api-arguments.h"
#include "src/builtins/builtins-descriptors.h"
#include "src/builtins/builtins-inl.h"
#include "src/codegen/code-factory.h"
#include "src/codegen/interface-descriptors-inl.h"
#include "src/debug/debug.h"
#include "src/deoptimizer/deoptimizer.h"
#include "src/execution/frame-constants.h"
#include "src/execution/frames.h"
#include "src/logging/counters.h"
// For interpreter_entry_return_pc_offset. TODO(jkummerow): Drop.
#include "src/codegen/macro-assembler-inl.h"
#include "src/codegen/register-configuration.h"
#include "src/heap/heap-inl.h"
#include "src/objects/cell.h"
#include "src/objects/foreign.h"
#include "src/objects/heap-number.h"
#include "src/objects/js-generator.h"
#include "src/objects/objects-inl.h"
#include "src/objects/smi.h"
#include "src/runtime/runtime.h"
 
#if V8_ENABLE_WEBASSEMBLY
#include "src/wasm/baseline/liftoff-assembler-defs.h"
#include "src/wasm/object-access.h"
#include "src/wasm/wasm-linkage.h"
#include "src/wasm/wasm-objects.h"
#endif  // V8_ENABLE_WEBASSEMBLY
 
namespace v8 {
namespace internal {
 
#define __ ACCESS_MASM(masm)
 
void Builtins::Generate_Adaptor(MacroAssembler* masm,
                                int formal_parameter_count, Address address) {
  ASM_CODE_COMMENT(masm);
  __ li(kJavaScriptCallExtraArg1Register, ExternalReference::Create(address));
  __ TailCallBuiltin(
      Builtins::AdaptorWithBuiltinExitFrame(formal_parameter_count));
}
 
namespace {
 
enum class ArgumentsElementType {
  kRaw,    // Push arguments as they are.
  kHandle  // Dereference arguments before pushing.
};
 
void Generate_PushArguments(MacroAssembler* masm, Register array, Register argc,
                            Register scratch, Register scratch2,
                            ArgumentsElementType element_type) {
  ASM_CODE_COMMENT(masm);
  DCHECK(!AreAliased(array, argc, scratch));
  Label loop, entry;
  __ SubWord(scratch, argc, Operand(kJSArgcReceiverSlots));
  __ Branch(&entry);
  __ bind(&loop);
  __ CalcScaledAddress(scratch2, array, scratch, kSystemPointerSizeLog2);
  __ LoadWord(scratch2, MemOperand(scratch2));
  if (element_type == ArgumentsElementType::kHandle) {
    __ LoadWord(scratch2, MemOperand(scratch2));
  }
  __ push(scratch2);
  __ bind(&entry);
  __ AddWord(scratch, scratch, Operand(-1));
  __ Branch(&loop, greater_equal, scratch, Operand(zero_reg));
}
 
void Generate_JSBuiltinsConstructStubHelper(MacroAssembler* masm) {
  // ----------- S t a t e -------------
  //  -- a0     : number of arguments
  //  -- a1     : constructor function
  //  -- a3     : new target
  //  -- cp     : context
  //  -- ra     : return address
  //  -- sp[...]: constructor arguments
  // -----------------------------------
 
  // Enter a construct frame.
  {
    FrameScope scope(masm, StackFrame::CONSTRUCT);
 
    // Preserve the incoming parameters on the stack.
    __ Push(cp, a0);
 
    // Set up pointer to first argument (skip receiver).
    __ AddWord(
        t2, fp,
        Operand(StandardFrameConstants::kCallerSPOffset + kSystemPointerSize));
    // t2: Pointer to start of arguments.
    // a0: Number of arguments.
    {
      UseScratchRegisterScope temps(masm);
      temps.Include(t0);
      Generate_PushArguments(masm, t2, a0, temps.Acquire(), temps.Acquire(),
                             ArgumentsElementType::kRaw);
    }
    // The receiver for the builtin/api call.
    __ PushRoot(RootIndex::kTheHoleValue);
 
    // Call the function.
    // a0: number of arguments (untagged)
    // a1: constructor function
    // a3: new target
    __ InvokeFunctionWithNewTarget(a1, a3, a0, InvokeType::kCall);
 
    // Restore context from the frame.
    __ LoadWord(cp, MemOperand(fp, ConstructFrameConstants::kContextOffset));
    // Restore arguments count from the frame.
    __ LoadWord(kScratchReg,
                MemOperand(fp, ConstructFrameConstants::kLengthOffset));
    // Leave construct frame.
  }
 
  // Remove caller arguments from the stack and return.
  __ DropArguments(kScratchReg);
  __ Ret();
}
 
}  // namespace
 
// The construct stub for ES5 constructor functions and ES6 class constructors.
void Builtins::Generate_JSConstructStubGeneric(MacroAssembler* masm) {
  // ----------- S t a t e -------------
  //  --      a0: number of arguments (untagged)
  //  --      a1: constructor function
  //  --      a3: new target
  //  --      cp: context
  //  --      ra: return address
  //  -- sp[...]: constructor arguments
  // -----------------------------------
  // Enter a construct frame.
  FrameScope scope(masm, StackFrame::MANUAL);
  Label post_instantiation_deopt_entry, not_create_implicit_receiver;
  __ EnterFrame(StackFrame::CONSTRUCT);
 
  // Preserve the incoming parameters on the stack.
  __ Push(cp, a0, a1);
  __ PushRoot(RootIndex::kUndefinedValue);
  __ Push(a3);
 
  // ----------- S t a t e -------------
  //  --        sp[0*kSystemPointerSize]: new target
  //  --        sp[1*kSystemPointerSize]: padding
  //  -- a1 and sp[2*kSystemPointerSize]: constructor function
  //  --        sp[3*kSystemPointerSize]: number of arguments
  //  --        sp[4*kSystemPointerSize]: context
  // -----------------------------------
  {
    UseScratchRegisterScope temps(masm);
    temps.Include(t1, t2);
    Register func_info = temps.Acquire();
    __ LoadTaggedField(
        func_info, FieldMemOperand(a1, JSFunction::kSharedFunctionInfoOffset));
    __ Load32U(func_info,
               FieldMemOperand(func_info, SharedFunctionInfo::kFlagsOffset));
    __ DecodeField<SharedFunctionInfo::FunctionKindBits>(func_info);
    __ JumpIfIsInRange(
        func_info,
        static_cast<uint32_t>(FunctionKind::kDefaultDerivedConstructor),
        static_cast<uint32_t>(FunctionKind::kDerivedConstructor),
        &not_create_implicit_receiver);
    // If not derived class constructor: Allocate the new receiver object.
    __ CallBuiltin(Builtin::kFastNewObject);
    __ BranchShort(&post_instantiation_deopt_entry);
 
    // Else: use TheHoleValue as receiver for constructor call
    __ bind(&not_create_implicit_receiver);
    __ LoadRoot(a0, RootIndex::kTheHoleValue);
  }
  // ----------- S t a t e -------------
  //  --                          a0: 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
  //  -- 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(a3);
 
  // Push the allocated receiver to the stack.
  __ Push(a0);
 
  // 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. The second copy is pushed after the arguments, we saved in a6
  // since a0 will store the return value of callRuntime.
  __ Move(a6, a0);
 
  // Set up pointer to first argument (skip receiver)..
  __ AddWord(
      t2, fp,
      Operand(StandardFrameConstants::kCallerSPOffset + kSystemPointerSize));
 
  // ----------- S t a t e -------------
  //  --                 a3: new target
  //  -- 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
  //  -- sp[5*kSystemPointerSize]: context
  // -----------------------------------
 
  // Restore constructor function and argument count.
  __ LoadWord(a1, MemOperand(fp, ConstructFrameConstants::kConstructorOffset));
  __ LoadWord(a0, MemOperand(fp, ConstructFrameConstants::kLengthOffset));
 
  Label stack_overflow;
  {
    UseScratchRegisterScope temps(masm);
    __ StackOverflowCheck(a0, temps.Acquire(), temps.Acquire(),
                          &stack_overflow);
  }
  // TODO(victorgomes): When the arguments adaptor is completely removed, we
  // should get the formal parameter count and copy the arguments in its
  // correct position (including any undefined), instead of delaying this to
  // InvokeFunction.
 
  // Copy arguments and receiver to the expression stack.
  // t2: Pointer to start of argument.
  // a0: Number of arguments.
  {
    UseScratchRegisterScope temps(masm);
    Generate_PushArguments(masm, t2, a0, temps.Acquire(), temps.Acquire(),
                           ArgumentsElementType::kRaw);
  }
  // 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. The second copy is pushed after the arguments,
  __ Push(a6);
 
  // Call the function.
  __ InvokeFunctionWithNewTarget(a1, a3, a0, InvokeType::kCall);
 
  // 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_and_return, check_receiver;
 
  // If the result is undefined, we jump out to using the implicit receiver.
  __ JumpIfNotRoot(a0, RootIndex::kUndefinedValue, &check_receiver);
 
  // Otherwise we do a smi check and fall through to check if the return value
  // is a valid receiver.
 
  // Throw away the result of the constructor invocation and use the
  // on-stack receiver as the result.
  __ bind(&use_receiver);
  __ LoadWord(a0, MemOperand(sp, 0 * kSystemPointerSize));
  __ JumpIfRoot(a0, RootIndex::kTheHoleValue, &do_throw);
 
  __ bind(&leave_and_return);
  // Restore  arguments count from the frame.
  __ LoadWord(a1, MemOperand(fp, ConstructFrameConstants::kLengthOffset));
  // Leave construct frame.
  __ LeaveFrame(StackFrame::CONSTRUCT);
 
  // Remove caller arguments from the stack and return.
  __ DropArguments(a1);
  __ Ret();
 
  __ bind(&check_receiver);
  __ JumpIfSmi(a0, &use_receiver);
 
  // 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.
  {
    UseScratchRegisterScope temps(masm);
    temps.Include(t1, t2);
    Register map = temps.Acquire(), type = temps.Acquire();
    __ GetObjectType(a0, map, type);
 
    static_assert(LAST_JS_RECEIVER_TYPE == LAST_TYPE);
    __ Branch(&leave_and_return, greater_equal, type,
              Operand(FIRST_JS_RECEIVER_TYPE));
    __ Branch(&use_receiver);
  }
  __ bind(&do_throw);
  // Restore the context from the frame.
  __ LoadWord(cp, MemOperand(fp, ConstructFrameConstants::kContextOffset));
  __ CallRuntime(Runtime::kThrowConstructorReturnedNonObject);
  __ break_(0xCC);
 
  __ bind(&stack_overflow);
  // Restore the context from the frame.
  __ LoadWord(cp, MemOperand(fp, ConstructFrameConstants::kContextOffset));
  __ CallRuntime(Runtime::kThrowStackOverflow);
  __ break_(0xCC);
}
 
void Builtins::Generate_JSBuiltinsConstructStub(MacroAssembler* masm) {
  Generate_JSBuiltinsConstructStubHelper(masm);
}
 
static void AssertCodeIsBaseline(MacroAssembler* masm, Register code,
                                 Register scratch) {
  DCHECK(!AreAliased(code, scratch));
  // Verify that the code kind is baseline code via the CodeKind.
  __ LoadWord(scratch, FieldMemOperand(code, Code::kFlagsOffset));
  __ DecodeField<Code::KindField>(scratch);
  __ Assert(eq, AbortReason::kExpectedBaselineData, scratch,
            Operand(static_cast<int64_t>(CodeKind::BASELINE)));
}
 
// TODO(v8:11429): Add a path for "not_compiled" and unify the two uses under
// the more general dispatch.
static void GetSharedFunctionInfoBytecodeOrBaseline(
    MacroAssembler* masm, Register sfi, Register bytecode, Register scratch1,
    Label* is_baseline, Label* is_unavailable) {
  DCHECK(!AreAliased(bytecode, scratch1));
  ASM_CODE_COMMENT(masm);
  Label done;
 
  Register data = bytecode;
  __ LoadTrustedPointerField(
      data,
      FieldMemOperand(sfi, SharedFunctionInfo::kTrustedFunctionDataOffset),
      kUnknownIndirectPointerTag);
 
  __ GetObjectType(data, scratch1, scratch1);
#ifndef V8_JITLESS
  if (v8_flags.debug_code) {
    Label not_baseline;
    __ Branch(&not_baseline, ne, scratch1, Operand(CODE_TYPE));
    AssertCodeIsBaseline(masm, data, scratch1);
    __ Branch(is_baseline);
    __ bind(&not_baseline);
  } else {
    __ Branch(is_baseline, eq, scratch1, Operand(CODE_TYPE));
  }
#endif  // !V8_JITLESS
  __ Branch(&done, eq, scratch1, Operand(BYTECODE_ARRAY_TYPE));
  __ Branch(is_unavailable, ne, scratch1, Operand(INTERPRETER_DATA_TYPE));
  __ LoadProtectedPointerField(
      bytecode, FieldMemOperand(data, InterpreterData::kBytecodeArrayOffset));
  __ bind(&done);
}
 
// static
void Builtins::Generate_ResumeGeneratorTrampoline(MacroAssembler* masm) {
  // ----------- S t a t e -------------
  //  -- a0 : the value to pass to the generator
  //  -- a1 : the JSGeneratorObject to resume
  //  -- ra : return address
  // -----------------------------------
  // Store input value into generator object.
  __ StoreTaggedField(
      a0, FieldMemOperand(a1, JSGeneratorObject::kInputOrDebugPosOffset));
  __ RecordWriteField(a1, JSGeneratorObject::kInputOrDebugPosOffset, a0,
                      kRAHasNotBeenSaved, SaveFPRegsMode::kIgnore);
  // Check that a1 is still valid, RecordWrite might have clobbered it.
  __ AssertGeneratorObject(a1);
 
  // Load suspended function and context.
  __ LoadTaggedField(a4,
                     FieldMemOperand(a1, JSGeneratorObject::kFunctionOffset));
  __ LoadTaggedField(cp, FieldMemOperand(a4, JSFunction::kContextOffset));
 
  // 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());
  __ li(a5, debug_hook);
  __ Lb(a5, MemOperand(a5));
  __ Branch(&prepare_step_in_if_stepping, ne, a5, Operand(zero_reg));
 
  // Flood function if we need to continue stepping in the suspended generator.
  ExternalReference debug_suspended_generator =
      ExternalReference::debug_suspended_generator_address(masm->isolate());
  __ li(a5, debug_suspended_generator);
  __ LoadWord(a5, MemOperand(a5));
  __ Branch(&prepare_step_in_suspended_generator, eq, a1, Operand(a5));
  __ 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;
  __ LoadStackLimit(kScratchReg, StackLimitKind::kRealStackLimit);
  __ Branch(&stack_overflow, Uless, sp, Operand(kScratchReg));
 
  // ----------- S t a t e -------------
  //  -- a1    : the JSGeneratorObject to resume
  //  -- a4    : generator function
  //  -- cp    : generator context
  //  -- ra    : return address
  // -----------------------------------
 
  // Push holes for arguments to generator function. Since the parser forced
  // context allocation for any variables in generators, the actual argument
  // values have already been copied into the context and these dummy values
  // will never be used.
  __ LoadTaggedField(
      a3, FieldMemOperand(a4, JSFunction::kSharedFunctionInfoOffset));
  __ Lhu(a3,
         FieldMemOperand(a3, SharedFunctionInfo::kFormalParameterCountOffset));
  __ SubWord(a3, a3, Operand(kJSArgcReceiverSlots));
  __ LoadTaggedField(
      t1,
      FieldMemOperand(a1, JSGeneratorObject::kParametersAndRegistersOffset));
  {
    Label done_loop, loop;
    __ bind(&loop);
    __ SubWord(a3, a3, Operand(1));
    __ Branch(&done_loop, lt, a3, Operand(zero_reg), Label::Distance::kNear);
    __ CalcScaledAddress(kScratchReg, t1, a3, kTaggedSizeLog2);
    __ LoadTaggedField(
        kScratchReg,
        FieldMemOperand(kScratchReg, OFFSET_OF_DATA_START(FixedArray)));
    __ Push(kScratchReg);
    __ Branch(&loop);
    __ bind(&done_loop);
    // Push receiver.
    __ LoadTaggedField(kScratchReg,
                       FieldMemOperand(a1, JSGeneratorObject::kReceiverOffset));
    __ Push(kScratchReg);
  }
 
  // Underlying function needs to have bytecode available.
  if (v8_flags.debug_code) {
    Label ok, is_baseline, is_unavailable;
    Register sfi = a3;
    Register bytecode = a3;
    __ LoadTaggedField(
        sfi, FieldMemOperand(a4, JSFunction::kSharedFunctionInfoOffset));
    GetSharedFunctionInfoBytecodeOrBaseline(masm, sfi, bytecode, t5,
                                            &is_baseline, &is_unavailable);
    __ Branch(&ok);
    __ bind(&is_unavailable);
    __ Abort(AbortReason::kMissingBytecodeArray);
    __ bind(&is_baseline);
    __ GetObjectType(bytecode, t5, t5);
    __ Assert(eq, AbortReason::kMissingBytecodeArray, t5, Operand(CODE_TYPE));
    __ bind(&ok);
  }
 
  // Resume (Ignition/TurboFan) generator object.
  {
    // TODO(40931165): use parameter count from JSDispatchTable and validate
    // that it matches the number of values in the JSGeneratorObject.
    __ LoadTaggedField(
        a0, FieldMemOperand(a4, JSFunction::kSharedFunctionInfoOffset));
    __ Lhu(a0, FieldMemOperand(
                   a0, 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.
    __ Move(a3, a1);
    __ Move(a1, a4);
    __ JumpJSFunction(a1);
  }
 
  __ bind(&prepare_step_in_if_stepping);
  {
    FrameScope scope(masm, StackFrame::INTERNAL);
    __ Push(a1, a4);
    // Push hole as receiver since we do not use it for stepping.
    __ PushRoot(RootIndex::kTheHoleValue);
    __ CallRuntime(Runtime::kDebugOnFunctionCall);
    __ Pop(a1);
  }
  __ LoadTaggedField(a4,
                     FieldMemOperand(a1, JSGeneratorObject::kFunctionOffset));
  __ Branch(&stepping_prepared);
 
  __ bind(&prepare_step_in_suspended_generator);
  {
    FrameScope scope(masm, StackFrame::INTERNAL);
    __ Push(a1);
    __ CallRuntime(Runtime::kDebugPrepareStepInSuspendedGenerator);
    __ Pop(a1);
  }
  __ LoadTaggedField(a4,
                     FieldMemOperand(a1, JSGeneratorObject::kFunctionOffset));
  __ Branch(&stepping_prepared);
 
  __ bind(&stack_overflow);
  {
    FrameScope scope(masm, StackFrame::INTERNAL);
    __ CallRuntime(Runtime::kThrowStackOverflow);
    __ break_(0xCC);  // This should be unreachable.
  }
}
 
void Builtins::Generate_ConstructedNonConstructable(MacroAssembler* masm) {
  FrameScope scope(masm, StackFrame::INTERNAL);
  __ Push(a1);
  __ CallRuntime(Runtime::kThrowConstructedNonConstructable);
}
 
// Clobbers scratch1 and scratch2; preserves all other registers.
static void Generate_CheckStackOverflow(MacroAssembler* masm, Register argc,
                                        Register scratch1, Register scratch2) {
  // 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.
  Label okay;
  __ LoadStackLimit(scratch1, StackLimitKind::kRealStackLimit);
  // Make a2 the space we have left. The stack might already be overflowed
  // here which will cause r2 to become negative.
  __ SubWord(scratch1, sp, scratch1);
  // Check if the arguments will overflow the stack.
  __ SllWord(scratch2, argc, kSystemPointerSizeLog2);
  __ Branch(&okay, gt, scratch1, Operand(scratch2),
            Label::Distance::kNear);  // Signed comparison.
 
  // Out of stack space.
  __ CallRuntime(Runtime::kThrowStackOverflow);
 
  __ bind(&okay);
}
 
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** args)>;
// or
//   using JSEntryFunction = GeneratedCode<Address(
//       Address root_register_value, MicrotaskQueue* microtask_queue)>;
void Generate_JSEntryVariant(MacroAssembler* masm, StackFrame::Type type,
                             Builtin entry_trampoline) {
  Label invoke, handler_entry, exit;
 
  {
    NoRootArrayScope no_root_array(masm);
 
    // TODO(plind): unify the ABI description here.
    // Registers:
    //  either
    //   a0: root register value
    //   a1: entry address
    //   a2: function
    //   a3: receiver
    //   a4: argc
    //   a5: argv
    //  or
    //   a0: root register value
    //   a1: microtask_queue
 
    // Save callee saved registers on the stack.
    __ MultiPush(kCalleeSaved | ra);
 
    // Save callee-saved FPU registers.
    __ MultiPushFPU(kCalleeSavedFPU);
    // Set up the reserved register for 0.0.
    __ LoadFPRImmediate(kDoubleRegZero, 0.0);
    __ LoadFPRImmediate(kSingleRegZero, 0.0f);
 
    // Initialize the root register.
    // C calling convention. The first argument is passed in a0.
    __ Move(kRootRegister, a0);
 
#ifdef V8_COMPRESS_POINTERS
    // Initialize the pointer cage base register.
    __ LoadRootRelative(kPtrComprCageBaseRegister,
                        IsolateData::cage_base_offset());
#endif
  }
 
  // a1: entry address
  // a2: function
  // a3: receiver
  // a4: argc
  // a5: argv
 
  // We build an EntryFrame.
  __ li(s1, Operand(-1));  // Push a bad frame pointer to fail if it is used.
  __ li(s2, Operand(StackFrame::TypeToMarker(type)));
  __ li(s3, Operand(StackFrame::TypeToMarker(type)));
  ExternalReference c_entry_fp = ExternalReference::Create(
      IsolateAddressId::kCEntryFPAddress, masm->isolate());
  __ li(s5, c_entry_fp);
  __ LoadWord(s4, MemOperand(s5));
  __ Push(s1, s2, s3, s4);
  // Clear c_entry_fp, now we've pushed its previous value to the stack.
  // If the c_entry_fp is not already zero and we don't clear it, the
  // StackFrameIteratorForProfiler will assume we are executing C++ and miss the
  // JS frames on top.
  __ StoreWord(zero_reg, MemOperand(s5));
 
  __ LoadIsolateField(s1, IsolateFieldId::kFastCCallCallerFP);
  __ LoadWord(s2, MemOperand(s1, 0));
  __ StoreWord(zero_reg, MemOperand(s1, 0));
 
  __ LoadIsolateField(s1, IsolateFieldId::kFastCCallCallerPC);
  __ LoadWord(s3, MemOperand(s1, 0));
  __ StoreWord(zero_reg, MemOperand(s1, 0));
  __ Push(s2, s3);
  // Set up frame pointer for the frame to be pushed.
  __ AddWord(fp, sp, -EntryFrameConstants::kNextFastCallFramePCOffset);
  // Registers:
  //  either
  //   a1: entry address
  //   a2: function
  //   a3: receiver
  //   a4: argc
  //   a5: argv
  //  or
  //   a1: microtask_queue
  //
  // Stack:
  // fast api call pc
  // fast api call fp
  // caller fp          |
  // function slot      | entry frame
  // context slot       |
  // bad fp (0xFF...F)  |
  // callee saved registers + ra
 
  // If this is the outermost JS call, set js_entry_sp value.
  Label non_outermost_js;
  ExternalReference js_entry_sp = ExternalReference::Create(
      IsolateAddressId::kJSEntrySPAddress, masm->isolate());
  __ li(s1, js_entry_sp);
  __ LoadWord(s2, MemOperand(s1));
  __ Branch(&non_outermost_js, ne, s2, Operand(zero_reg),
            Label::Distance::kNear);
  __ StoreWord(fp, MemOperand(s1));
  __ li(s3, Operand(StackFrame::OUTERMOST_JSENTRY_FRAME));
  Label cont;
  __ Branch(&cont);
  __ bind(&non_outermost_js);
  __ li(s3, Operand(StackFrame::INNER_JSENTRY_FRAME));
  __ bind(&cont);
  __ push(s3);
 
  // Jump to a faked try block that does the invoke, with a faked catch
  // block that sets the exception.
  __ BranchShort(&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 exception
  // field in the JSEnv and return a failure sentinel.  Coming in here the
  // fp will be invalid because the PushStackHandler below sets it to 0 to
  // signal the existence of the JSEntry frame.
  __ li(s1, ExternalReference::Create(IsolateAddressId::kExceptionAddress,
                                      masm->isolate()));
  __ StoreWord(a0,
               MemOperand(s1));  // We come back from 'invoke'. result is in a0.
  __ LoadRoot(a0, RootIndex::kException);
  __ BranchShort(&exit);
 
  // Invoke: Link this frame into the handler chain.
  __ bind(&invoke);
  __ PushStackHandler();
  // If an exception not caught by another handler occurs, this handler
  // returns control to the code after the bal(&invoke) above, which
  // restores all kCalleeSaved registers (including cp and fp) to their
  // saved values before returning a failure to C.
  //
  // Registers:
  //  either
  //   a0: root register value
  //   a1: entry address
  //   a2: function
  //   a3: receiver
  //   a4: argc
  //   a5: argv
  //  or
  //   a0: root register value
  //   a1: microtask_queue
  //
  // Stack:
  // fast api call pc.
  // fast api call fp.
  // JS entry frame marker
  // caller fp          |
  // function slot      | entry frame
  // context slot       |
  // bad fp (0xFF...F)  |
  // handler frame
  // entry frame
  // callee saved registers + ra
  // [ O32: 4 args slots]
  // args
  //
  // Invoke the function by calling through JS entry trampoline builtin and
  // pop the faked function when we return.
  __ CallBuiltin(entry_trampoline);
 
  // Unlink this frame from the handler chain.
  __ PopStackHandler();
 
  __ bind(&exit);  // a0 holds result
  // Check if the current stack frame is marked as the outermost JS frame.
 
  Label non_outermost_js_2;
  __ pop(a5);
  __ Branch(&non_outermost_js_2, ne, a5,
            Operand(StackFrame::OUTERMOST_JSENTRY_FRAME),
            Label::Distance::kNear);
  __ li(a5, js_entry_sp);
  __ StoreWord(zero_reg, MemOperand(a5));
  __ bind(&non_outermost_js_2);
 
  __ Pop(s2, s3);
  __ LoadIsolateField(s1, IsolateFieldId::kFastCCallCallerFP);
  __ StoreWord(s2, MemOperand(s1, 0));
  __ LoadIsolateField(s1, IsolateFieldId::kFastCCallCallerPC);
  __ StoreWord(s3, MemOperand(s1, 0));
  // Restore the top frame descriptors from the stack.
  __ pop(a5);
  __ li(a4, ExternalReference::Create(IsolateAddressId::kCEntryFPAddress,
                                      masm->isolate()));
  __ StoreWord(a5, MemOperand(a4));
 
  // Reset the stack to the callee saved registers.
  __ AddWord(sp, sp, -EntryFrameConstants::kNextExitFrameFPOffset);
 
  // Restore callee-saved fpu registers.
  __ MultiPopFPU(kCalleeSavedFPU);
 
  // Restore callee saved registers from the stack.
  __ MultiPop(kCalleeSaved | ra);
  // Return.
  __ Jump(ra);
}
 
}  // namespace
 
void Builtins::Generate_JSEntry(MacroAssembler* masm) {
  Generate_JSEntryVariant(masm, StackFrame::ENTRY, Builtin::kJSEntryTrampoline);
}
 
void Builtins::Generate_JSConstructEntry(MacroAssembler* masm) {
  Generate_JSEntryVariant(masm, StackFrame::CONSTRUCT_ENTRY,
                          Builtin::kJSConstructEntryTrampoline);
}
 
void Builtins::Generate_JSRunMicrotasksEntry(MacroAssembler* masm) {
  Generate_JSEntryVariant(masm, StackFrame::ENTRY,
                          Builtin::kRunMicrotasksTrampoline);
}
 
static void Generate_JSEntryTrampolineHelper(MacroAssembler* masm,
                                             bool is_construct) {
  // ----------- S t a t e -------------
  //  -- a1: new.target
  //  -- a2: function
  //  -- a3: receiver_pointer
  //  -- a4: argc
  //  -- a5: argv
  // -----------------------------------
 
  // 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());
    __ li(cp, context_address);
    __ LoadWord(cp, MemOperand(cp));
 
    // Push the function onto the stack.
    __ Push(a2);
 
    // Check if we have enough stack space to push all arguments.
    __ mv(a6, a4);
    Generate_CheckStackOverflow(masm, a6, a0, s2);
 
    // Copy arguments to the stack.
    // a4: argc
    // a5: argv, i.e. points to first arg
    {
      UseScratchRegisterScope temps(masm);
      Generate_PushArguments(masm, a5, a4, temps.Acquire(), temps.Acquire(),
                             ArgumentsElementType::kHandle);
    }
    // Push the receive.
    __ Push(a3);
 
    // a0: argc
    // a1: function
    // a3: new.target
    __ Move(a3, a1);
    __ Move(a1, a2);
    __ Move(a0, a4);
 
    // Initialize all JavaScript callee-saved registers, since they will be seen
    // by the garbage collector as part of handlers.
    __ LoadRoot(a4, RootIndex::kUndefinedValue);
    __ Move(a5, a4);
    __ Move(s1, a4);
    __ Move(s2, a4);
    __ Move(s3, a4);
    __ Move(s4, a4);
    __ Move(s5, a4);
    __ Move(s8, a4);
    __ Move(s9, a4);
    __ Move(s10, a4);
#ifndef V8_COMPRESS_POINTERS
    __ Move(s11, a4);
#endif
    // s6 holds the root address. Do not clobber.
    // s7 is cp. Do not init.
    // s11 is pointer cage base register (kPointerCageBaseRegister).
 
    // Invoke the code.
    Builtin builtin = is_construct ? Builtin::kConstruct : Builtins::Call();
    __ CallBuiltin(builtin);
 
    // Leave internal frame.
  }
  __ Jump(ra);
}
 
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) {
  // a1: microtask_queue
  __ Move(RunMicrotasksDescriptor::MicrotaskQueueRegister(), a1);
  __ TailCallBuiltin(Builtin::kRunMicrotasks);
}
 
static void LeaveInterpreterFrame(MacroAssembler* masm, Register scratch1,
                                  Register scratch2) {
  ASM_CODE_COMMENT(masm);
  Register params_size = scratch1;
 
  // Get the size of the formal parameters + receiver (in bytes).
  __ LoadWord(params_size,
              MemOperand(fp, InterpreterFrameConstants::kBytecodeArrayFromFp));
  __ Lhu(params_size,
         FieldMemOperand(params_size, BytecodeArray::kParameterSizeOffset));
 
  Register actual_params_size = scratch2;
  Label L1;
  // Compute the size of the actual parameters + receiver (in bytes).
  __ LoadWord(actual_params_size,
              MemOperand(fp, StandardFrameConstants::kArgCOffset));
  // If actual is bigger than formal, then we should use it to free up the stack
  // arguments.
  __ Branch(&L1, le, actual_params_size, Operand(params_size),
            Label::Distance::kNear);
  __ Move(params_size, actual_params_size);
  __ bind(&L1);
 
  // Leave the frame (also dropping the register file).
  __ LeaveFrame(StackFrame::INTERPRETED);
 
  // Drop receiver + arguments.
  __ DropArguments(params_size);
}
 
// 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. Will not advance
// the bytecode offset if the current bytecode is a JumpLoop, instead just
// re-executing the JumpLoop to jump to the correct bytecode.
static void AdvanceBytecodeOffsetOrReturn(MacroAssembler* masm,
                                          Register bytecode_array,
                                          Register bytecode_offset,
                                          Register bytecode, Register scratch1,
                                          Register scratch2, Register scratch3,
                                          Label* if_return) {
  ASM_CODE_COMMENT(masm);
  Register bytecode_size_table = scratch1;
 
  // The bytecode offset value will be increased by one in wide and extra wide
  // cases. In the case of having a wide or extra wide JumpLoop bytecode, we
  // will restore the original bytecode. In order to simplify the code, we have
  // a backup of it.
  Register original_bytecode_offset = scratch3;
  DCHECK(!AreAliased(bytecode_array, bytecode_offset, bytecode,
                     bytecode_size_table, original_bytecode_offset));
  __ Move(original_bytecode_offset, bytecode_offset);
  __ li(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));
  __ Branch(&process_bytecode, Ugreater, bytecode, Operand(3),
            Label::Distance::kNear);
  __ And(scratch2, bytecode, Operand(1));
  __ Branch(&extra_wide, ne, scratch2, Operand(zero_reg),
            Label::Distance::kNear);
 
  // Load the next bytecode and update table to the wide scaled table.
  __ AddWord(bytecode_offset, bytecode_offset, Operand(1));
  __ AddWord(scratch2, bytecode_array, bytecode_offset);
  __ Lbu(bytecode, MemOperand(scratch2));
  __ AddWord(bytecode_size_table, bytecode_size_table,
             Operand(kByteSize * interpreter::Bytecodes::kBytecodeCount));
  __ BranchShort(&process_bytecode);
 
  __ bind(&extra_wide);
  // Load the next bytecode and update table to the extra wide scaled table.
  __ AddWord(bytecode_offset, bytecode_offset, Operand(1));
  __ AddWord(scratch2, bytecode_array, bytecode_offset);
  __ Lbu(bytecode, MemOperand(scratch2));
  __ AddWord(bytecode_size_table, bytecode_size_table,
             Operand(2 * kByteSize * interpreter::Bytecodes::kBytecodeCount));
 
  __ bind(&process_bytecode);
 
// Bailout to the return label if this is a return bytecode.
#define JUMP_IF_EQUAL(NAME)          \
  __ Branch(if_return, eq, bytecode, \
            Operand(static_cast<int64_t>(interpreter::Bytecode::k##NAME)));
  RETURN_BYTECODE_LIST(JUMP_IF_EQUAL)
#undef JUMP_IF_EQUAL
 
  // If this is a JumpLoop, re-execute it to perform the jump to the beginning
  // of the loop.
  Label end, not_jump_loop;
  __ Branch(&not_jump_loop, ne, bytecode,
            Operand(static_cast<int64_t>(interpreter::Bytecode::kJumpLoop)),
            Label::Distance::kNear);
  // We need to restore the original bytecode_offset since we might have
  // increased it to skip the wide / extra-wide prefix bytecode.
  __ Move(bytecode_offset, original_bytecode_offset);
  __ BranchShort(&end);
 
  __ bind(&not_jump_loop);
  // Otherwise, load the size of the current bytecode and advance the offset.
  __ AddWord(scratch2, bytecode_size_table, bytecode);
  __ Lb(scratch2, MemOperand(scratch2));
  __ AddWord(bytecode_offset, bytecode_offset, scratch2);
 
  __ bind(&end);
}
 
namespace {
void ResetSharedFunctionInfoAge(MacroAssembler* masm, Register sfi) {
  __ Sh(zero_reg, FieldMemOperand(sfi, SharedFunctionInfo::kAgeOffset));
}
 
void ResetJSFunctionAge(MacroAssembler* masm, Register js_function,
                        Register scratch) {
  const Register shared_function_info(scratch);
  __ LoadTaggedField(
      shared_function_info,
      FieldMemOperand(js_function, JSFunction::kSharedFunctionInfoOffset));
  ResetSharedFunctionInfoAge(masm, shared_function_info);
}
 
void ResetFeedbackVectorOsrUrgency(MacroAssembler* masm,
                                   Register feedback_vector, Register scratch) {
  DCHECK(!AreAliased(feedback_vector, scratch));
  __ Lbu(scratch,
         FieldMemOperand(feedback_vector, FeedbackVector::kOsrStateOffset));
  __ And(scratch, scratch, Operand(~FeedbackVector::OsrUrgencyBits::kMask));
  __ Sb(scratch,
        FieldMemOperand(feedback_vector, FeedbackVector::kOsrStateOffset));
}
 
}  // namespace
 
// static
void Builtins::Generate_BaselineOutOfLinePrologue(MacroAssembler* masm) {
  ASM_CODE_COMMENT(masm);
  UseScratchRegisterScope temps(masm);
  temps.Include({kScratchReg, kScratchReg2, s1});
  auto descriptor =
      Builtins::CallInterfaceDescriptorFor(Builtin::kBaselineOutOfLinePrologue);
  Register closure = descriptor.GetRegisterParameter(
      BaselineOutOfLinePrologueDescriptor::kClosure);
  // Load the feedback cell and vector from the closure.
  Register feedback_cell = temps.Acquire();
  Register feedback_vector = temps.Acquire();
  __ LoadTaggedField(feedback_cell,
                     FieldMemOperand(closure, JSFunction::kFeedbackCellOffset));
  __ LoadTaggedField(
      feedback_vector,
      FieldMemOperand(feedback_cell, FeedbackCell::kValueOffset));
  {
    UseScratchRegisterScope temp(masm);
    Register type = temps.Acquire();
    __ AssertFeedbackVector(feedback_vector, type);
  }
 
#ifndef V8_ENABLE_LEAPTIERING
  // Check for an tiering state.
  Label flags_need_processing;
  Register flags = temps.Acquire();
  __ LoadFeedbackVectorFlagsAndJumpIfNeedsProcessing(
      flags, feedback_vector, CodeKind::BASELINE, &flags_need_processing);
#endif  // !V8_ENABLE_LEAPTIERING
 
  {
    UseScratchRegisterScope temps(masm);
    ResetFeedbackVectorOsrUrgency(masm, feedback_vector, temps.Acquire());
  }
  // Increment invocation count for the function.
  {
    UseScratchRegisterScope temps(masm);
    Register invocation_count = temps.Acquire();
    __ Lw(invocation_count,
          FieldMemOperand(feedback_vector,
                          FeedbackVector::kInvocationCountOffset));
    __ Add32(invocation_count, invocation_count, Operand(1));
    __ Sw(invocation_count,
          FieldMemOperand(feedback_vector,
                          FeedbackVector::kInvocationCountOffset));
  }
 
  FrameScope frame_scope(masm, StackFrame::MANUAL);
  {
    ASM_CODE_COMMENT_STRING(masm, "Frame Setup");
    // Normally the first thing we'd do here is Push(ra, fp), but we already
    // entered the frame in BaselineCompiler::Prologue, as we had to use the
    // value ra before the call to this BaselineOutOfLinePrologue builtin.
    Register callee_context = descriptor.GetRegisterParameter(
        BaselineOutOfLinePrologueDescriptor::kCalleeContext);
    Register callee_js_function = descriptor.GetRegisterParameter(
        BaselineOutOfLinePrologueDescriptor::kClosure);
    {
      UseScratchRegisterScope temps(masm);
      ResetJSFunctionAge(masm, callee_js_function, temps.Acquire());
    }
    __ Push(callee_context, callee_js_function);
    DCHECK_EQ(callee_js_function, kJavaScriptCallTargetRegister);
    DCHECK_EQ(callee_js_function, kJSFunctionRegister);
 
    Register argc = descriptor.GetRegisterParameter(
        BaselineOutOfLinePrologueDescriptor::kJavaScriptCallArgCount);
    // We'll use the bytecode for both code age/OSR resetting, and pushing onto
    // the frame, so load it into a register.
    Register bytecode_array = descriptor.GetRegisterParameter(
        BaselineOutOfLinePrologueDescriptor::kInterpreterBytecodeArray);
    __ Push(argc, bytecode_array, feedback_cell, feedback_vector);
    // Baseline code frames store the feedback vector where interpreter would
    // store the bytecode offset.
    {
      UseScratchRegisterScope temp(masm);
      Register type = temps.Acquire();
      __ AssertFeedbackVector(feedback_vector, type);
    }
  }
 
  Label call_stack_guard;
  Register frame_size = descriptor.GetRegisterParameter(
      BaselineOutOfLinePrologueDescriptor::kStackFrameSize);
  {
    ASM_CODE_COMMENT_STRING(masm, "Stack/interrupt check");
    // Stack check. This folds the checks for both the interrupt stack limit
    // check and the real stack limit into one by just checking for the
    // interrupt limit. The interrupt limit is either equal to the real stack
    // limit or tighter. By ensuring we have space until that limit after
    // building the frame we can quickly precheck both at once.
    UseScratchRegisterScope temps(masm);
    Register sp_minus_frame_size = temps.Acquire();
    __ SubWord(sp_minus_frame_size, sp, frame_size);
    Register interrupt_limit = temps.Acquire();
    __ LoadStackLimit(interrupt_limit, StackLimitKind::kInterruptStackLimit);
    __ Branch(&call_stack_guard, Uless, sp_minus_frame_size,
              Operand(interrupt_limit));
  }
 
  // Do "fast" return to the caller pc in ra.
  // TODO(v8:11429): Document this frame setup better.
  __ Ret();
 
#ifndef V8_ENABLE_LEAPTIERING
  __ bind(&flags_need_processing);
  {
    ASM_CODE_COMMENT_STRING(masm, "Optimized marker check");
    // Drop the frame created by the baseline call.
    __ Pop(ra, fp);
    __ OptimizeCodeOrTailCallOptimizedCodeSlot(flags, feedback_vector);
    __ Trap();
  }
#endif  // !V8_ENABLE_LEAPTIERING
 
  __ bind(&call_stack_guard);
  {
    ASM_CODE_COMMENT_STRING(masm, "Stack/interrupt call");
    FrameScope frame_scope(masm, StackFrame::INTERNAL);
    // Save incoming new target or generator
    __ Push(kJavaScriptCallNewTargetRegister);
#if defined(V8_ENABLE_LEAPTIERING) && defined(V8_TARGET_ARCH_RISCV64)
    // No need to SmiTag as dispatch handles always look like Smis.
    static_assert(kJSDispatchHandleShift > 0);
    __ Push(kJavaScriptCallDispatchHandleRegister);
#endif
    __ SmiTag(frame_size);
    __ Push(frame_size);
    __ CallRuntime(Runtime::kStackGuardWithGap);
#if defined(V8_ENABLE_LEAPTIERING) && defined(V8_TARGET_ARCH_RISCV64)
    __ Pop(kJavaScriptCallDispatchHandleRegister);
#endif
    __ Pop(kJavaScriptCallNewTargetRegister);
  }
  __ Ret();
  temps.Exclude({kScratchReg, kScratchReg2, s1});
}
 
// static
void Builtins::Generate_BaselineOutOfLinePrologueDeopt(MacroAssembler* masm) {
  // We're here because we got deopted during BaselineOutOfLinePrologue's stack
  // check. Undo all its frame creation and call into the interpreter instead.
 
  // Drop bytecode offset (was the feedback vector but got replaced during
  // deopt) and bytecode array.
  __ AddWord(sp, sp, Operand(3 * kSystemPointerSize));
 
  // Context, closure, argc.
  __ Pop(kContextRegister, kJavaScriptCallTargetRegister,
         kJavaScriptCallArgCountRegister);
 
  // Drop frame pointer
  __ LeaveFrame(StackFrame::BASELINE);
 
  // Enter the interpreter.
  __ TailCallBuiltin(Builtin::kInterpreterEntryTrampoline);
}
 
// 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 live registers are:
//   o a0 : actual argument count
//   o a1: the JS function object being called.
//   o a3: the incoming new target or generator object
//   o a4: the dispatch handle through which we were called
//   o cp: our context
//   o fp: the caller's frame pointer
//   o sp: stack pointer
//   o ra: return address
//
// The function builds an interpreter frame.  See InterpreterFrameConstants in
// frames-constants.h for its layout.
void Builtins::Generate_InterpreterEntryTrampoline(
    MacroAssembler* masm, InterpreterEntryTrampolineMode mode) {
  Register closure = a1;
  // Get the bytecode array from the function object and load it into
  // kInterpreterBytecodeArrayRegister.
  Register sfi = a5;
  __ LoadTaggedField(
      sfi, FieldMemOperand(closure, JSFunction::kSharedFunctionInfoOffset));
  ResetSharedFunctionInfoAge(masm, sfi);
 
  // The bytecode array could have been flushed from the shared function info,
  // if so, call into CompileLazy.
  Label is_baseline, compile_lazy;
  GetSharedFunctionInfoBytecodeOrBaseline(
      masm, sfi, kInterpreterBytecodeArrayRegister, kScratchReg, &is_baseline,
      &compile_lazy);
 
#ifdef V8_ENABLE_SANDBOX
  // Validate the parameter count. This protects against an attacker swapping
  // the bytecode (or the dispatch handle) such that the parameter count of the
  // dispatch entry doesn't match the one of the BytecodeArray.
  // TODO(saelo): instead of this validation step, it would probably be nicer
  // if we could store the BytecodeArray directly in the dispatch entry and
  // load it from there. Then we can easily guarantee that the parameter count
  // of the entry matches the parameter count of the bytecode.
  static_assert(V8_JS_LINKAGE_INCLUDES_DISPATCH_HANDLE_BOOL);
  Register dispatch_handle = kJavaScriptCallDispatchHandleRegister;  // a4
  __ LoadParameterCountFromJSDispatchTable(a2, dispatch_handle, a6);
  __ Lh(a6, FieldMemOperand(kInterpreterBytecodeArrayRegister,
                            BytecodeArray::kParameterSizeOffset));
  __ SbxCheck(eq, AbortReason::kJSSignatureMismatch, a2, Operand(a6));
#endif  // V8_ENABLE_SANDBOX
 
  Label push_stack_frame;
  Register feedback_vector = a2;
  __ LoadFeedbackVector(feedback_vector, closure, a6, &push_stack_frame);
 
#ifndef V8_JITLESS
#ifndef V8_ENABLE_LEAPTIERING
  // If feedback vector is valid, check for optimized code and update invocation
  // count.
 
  // Check the tiering state.
  Label flags_need_processing;
  Register flags = a6;
  __ LoadFeedbackVectorFlagsAndJumpIfNeedsProcessing(
      flags, feedback_vector, CodeKind::INTERPRETED_FUNCTION,
      &flags_need_processing);
#endif  // V8_ENABLE_LEAPTIERING
  ResetFeedbackVectorOsrUrgency(masm, feedback_vector, a4);
 
  // Increment invocation count for the function.
  __ Lw(a6, FieldMemOperand(feedback_vector,
                            FeedbackVector::kInvocationCountOffset));
  __ Add32(a6, a6, Operand(1));
  __ Sw(a6, FieldMemOperand(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).
#else
  // Note: By omitting the above code in jitless mode we also disable:
  // - kFlagsLogNextExecution: only used for logging/profiling; and
  // - kInvocationCountOffset: only used for tiering heuristics and code
  //   coverage.
#endif  // !V8_JITLESS
 
  __ bind(&push_stack_frame);
  FrameScope frame_scope(masm, StackFrame::MANUAL);
  __ PushStandardFrame(closure);
 
  // Load initial bytecode offset.
  __ li(kInterpreterBytecodeOffsetRegister,
        Operand(BytecodeArray::kHeaderSize - kHeapObjectTag));
 
  // Push bytecode array, Smi tagged bytecode array offset, and the feedback
  // vector.
  __ SmiTag(a6, kInterpreterBytecodeOffsetRegister);
  __ Push(kInterpreterBytecodeArrayRegister, a6, feedback_vector);
 
  // Allocate the local and temporary register file on the stack.
  Label stack_overflow;
  {
    // Load frame size (word) from the BytecodeArray object.
    __ Lw(a6, FieldMemOperand(kInterpreterBytecodeArrayRegister,
                              BytecodeArray::kFrameSizeOffset));
 
    // Do a stack check to ensure we don't go over the limit.
    __ SubWord(a5, sp, Operand(a6));
    __ LoadStackLimit(a2, StackLimitKind::kRealStackLimit);
    __ Branch(&stack_overflow, Uless, a5, Operand(a2));
 
    // If ok, push undefined as the initial value for all register file entries.
    Label loop_header;
    Label loop_check;
    __ LoadRoot(kInterpreterAccumulatorRegister, RootIndex::kUndefinedValue);
    __ BranchShort(&loop_check);
    __ bind(&loop_header);
    // TODO(rmcilroy): Consider doing more than one push per loop iteration.
    __ push(kInterpreterAccumulatorRegister);
    // Continue loop if not done.
    __ bind(&loop_check);
    __ SubWord(a6, a6, Operand(kSystemPointerSize));
    __ Branch(&loop_header, ge, a6, Operand(zero_reg));
  }
 
  // If the bytecode array has a valid incoming new target or generator object
  // register, initialize it with incoming value which was passed in a3.
  Label no_incoming_new_target_or_generator_register;
  __ Lw(a5, FieldMemOperand(
                kInterpreterBytecodeArrayRegister,
                BytecodeArray::kIncomingNewTargetOrGeneratorRegisterOffset));
  __ Branch(&no_incoming_new_target_or_generator_register, eq, a5,
            Operand(zero_reg), Label::Distance::kNear);
  __ CalcScaledAddress(a5, fp, a5, kSystemPointerSizeLog2);
  __ StoreWord(a3, MemOperand(a5));
  __ bind(&no_incoming_new_target_or_generator_register);
 
  // Perform interrupt stack check.
  // TODO(solanes): Merge with the real stack limit check above.
  Label stack_check_interrupt, after_stack_check_interrupt;
  __ LoadStackLimit(a5, StackLimitKind::kInterruptStackLimit);
  __ Branch(&stack_check_interrupt, Uless, sp, Operand(a5),
            Label::Distance::kNear);
  __ bind(&after_stack_check_interrupt);
 
  // Load the dispatch table into a register and dispatch to the bytecode
  // handler at the current bytecode offset.
  Label do_dispatch;
  __ bind(&do_dispatch);
  __ li(kInterpreterDispatchTableRegister,
        ExternalReference::interpreter_dispatch_table_address(masm->isolate()));
  __ AddWord(a1, kInterpreterBytecodeArrayRegister,
             kInterpreterBytecodeOffsetRegister);
  __ Lbu(a7, MemOperand(a1));
  __ CalcScaledAddress(kScratchReg, kInterpreterDispatchTableRegister, a7,
                       kSystemPointerSizeLog2);
  __ LoadWord(kJavaScriptCallCodeStartRegister, MemOperand(kScratchReg));
  __ Call(kJavaScriptCallCodeStartRegister);
 
  __ RecordComment("--- InterpreterEntryReturnPC point ---");
  if (mode == InterpreterEntryTrampolineMode::kDefault) {
    masm->isolate()->heap()->SetInterpreterEntryReturnPCOffset(
        masm->pc_offset());
  } else {
    DCHECK_EQ(mode, InterpreterEntryTrampolineMode::kForProfiling);
    // Both versions must be the same up to this point otherwise the builtins
    // will not be interchangable.
    CHECK_EQ(
        masm->isolate()->heap()->interpreter_entry_return_pc_offset().value(),
        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.
  __ LoadWord(kInterpreterBytecodeArrayRegister,
              MemOperand(fp, InterpreterFrameConstants::kBytecodeArrayFromFp));
  __ LoadWord(kInterpreterBytecodeOffsetRegister,
              MemOperand(fp, InterpreterFrameConstants::kBytecodeOffsetFromFp));
  __ SmiUntag(kInterpreterBytecodeOffsetRegister);
 
  // Either return, or advance to the next bytecode and dispatch.
  Label do_return;
  __ AddWord(a1, kInterpreterBytecodeArrayRegister,
             kInterpreterBytecodeOffsetRegister);
  __ Lbu(a1, MemOperand(a1));
  AdvanceBytecodeOffsetOrReturn(masm, kInterpreterBytecodeArrayRegister,
                                kInterpreterBytecodeOffsetRegister, a1, a2, a3,
                                a5, &do_return);
  __ Branch(&do_dispatch);
 
  __ bind(&do_return);
  // The return value is in a0.
  LeaveInterpreterFrame(masm, t0, t1);
  __ Jump(ra);
 
  __ bind(&stack_check_interrupt);
  // Modify the bytecode offset in the stack to be kFunctionEntryBytecodeOffset
  // for the call to the StackGuard.
  __ li(kInterpreterBytecodeOffsetRegister,
        Operand(Smi::FromInt(BytecodeArray::kHeaderSize - kHeapObjectTag +
                             kFunctionEntryBytecodeOffset)));
  __ StoreWord(
      kInterpreterBytecodeOffsetRegister,
      MemOperand(fp, InterpreterFrameConstants::kBytecodeOffsetFromFp));
  __ CallRuntime(Runtime::kStackGuard);
 
  // After the call, restore the bytecode array, bytecode offset and accumulator
  // registers again. Also, restore the bytecode offset in the stack to its
  // previous value.
  __ LoadWord(kInterpreterBytecodeArrayRegister,
              MemOperand(fp, InterpreterFrameConstants::kBytecodeArrayFromFp));
  __ li(kInterpreterBytecodeOffsetRegister,
        Operand(BytecodeArray::kHeaderSize - kHeapObjectTag));
  __ LoadRoot(kInterpreterAccumulatorRegister, RootIndex::kUndefinedValue);
 
  __ SmiTag(a5, kInterpreterBytecodeOffsetRegister);
  __ StoreWord(
      a5, MemOperand(fp, InterpreterFrameConstants::kBytecodeOffsetFromFp));
 
  __ Branch(&after_stack_check_interrupt);
 
#ifndef V8_JITLESS
#ifndef V8_ENABLE_LEAPTIERING
  __ bind(&flags_need_processing);
  __ OptimizeCodeOrTailCallOptimizedCodeSlot(flags, feedback_vector);
#endif  // !V8_ENABLE_LEAPTIERING
  __ bind(&is_baseline);
  {
#ifndef V8_ENABLE_LEAPTIERING
    // Load the feedback vector from the closure.
    __ LoadTaggedField(
        feedback_vector,
        FieldMemOperand(closure, JSFunction::kFeedbackCellOffset));
    __ LoadTaggedField(
        feedback_vector,
        FieldMemOperand(feedback_vector, FeedbackCell::kValueOffset));
 
    Label install_baseline_code;
    // Check if feedback vector is valid. If not, call prepare for baseline to
    // allocate it.
    __ LoadTaggedField(
        t0, FieldMemOperand(feedback_vector, HeapObject::kMapOffset));
    __ Lhu(t0, FieldMemOperand(t0, Map::kInstanceTypeOffset));
    __ Branch(&install_baseline_code, ne, t0, Operand(FEEDBACK_VECTOR_TYPE));
 
    // Check for an tiering state.
    __ LoadFeedbackVectorFlagsAndJumpIfNeedsProcessing(
        flags, feedback_vector, CodeKind::BASELINE, &flags_need_processing);
 
    // TODO(olivf, 42204201): This fastcase is difficult to support with the
    // sandbox as it requires getting write access to the dispatch table. See
    // `JSFunction::UpdateCode`. We might want to remove it for all
    // configurations as it does not seem to be performance sensitive.
    // Load the baseline code into the closure.
    __ Move(a2, kInterpreterBytecodeArrayRegister);
    static_assert(kJavaScriptCallCodeStartRegister == a2, "ABI mismatch");
    __ ReplaceClosureCodeWithOptimizedCode(a2, closure);
    __ JumpCodeObject(a2, kJSEntrypointTag);
 
    __ bind(&install_baseline_code);
#endif  // !V8_ENABLE_LEAPTIERING
    __ GenerateTailCallToReturnedCode(Runtime::kInstallBaselineCode);
  }
#endif  // !V8_JITLESS
 
  __ bind(&compile_lazy);
  __ GenerateTailCallToReturnedCode(Runtime::kCompileLazy);
  // Unreachable code.
  __ break_(0xCC);
 
  __ bind(&stack_overflow);
  __ CallRuntime(Runtime::kThrowStackOverflow);
  // Unreachable code.
  __ break_(0xCC);
}
 
static void GenerateInterpreterPushArgs(MacroAssembler* masm, Register num_args,
                                        Register start_address,
                                        Register scratch) {
  ASM_CODE_COMMENT(masm);
  // Find the address of the last argument.
  __ SubWord(scratch, num_args, Operand(1));
  __ SllWord(scratch, scratch, kSystemPointerSizeLog2);
  __ SubWord(start_address, start_address, scratch);
 
  // Push the arguments.
  __ PushArray(start_address, num_args,
               MacroAssembler::PushArrayOrder::kReverse);
}
 
// static
void Builtins::Generate_InterpreterPushArgsThenCallImpl(
    MacroAssembler* masm, ConvertReceiverMode receiver_mode,
    InterpreterPushArgsMode mode) {
  DCHECK(mode != InterpreterPushArgsMode::kArrayFunction);
  // ----------- S t a t e -------------
  //  -- a0 : the number of arguments
  //  -- a2 : 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.
  //  -- a1 : the target to call (can be any Object).
  // -----------------------------------
  Label stack_overflow;
  if (mode == InterpreterPushArgsMode::kWithFinalSpread) {
    // The spread argument should not be pushed.
    __ SubWord(a0, a0, Operand(1));
  }
 
  if (receiver_mode == ConvertReceiverMode::kNullOrUndefined) {
    __ SubWord(a3, a0, Operand(kJSArgcReceiverSlots));
  } else {
    __ Move(a3, a0);
  }
  __ StackOverflowCheck(a3, a4, t0, &stack_overflow);
 
  // This function modifies a2 and a4.
  GenerateInterpreterPushArgs(masm, a3, a2, a4);
  if (receiver_mode == ConvertReceiverMode::kNullOrUndefined) {
    __ PushRoot(RootIndex::kUndefinedValue);
  }
 
  if (mode == InterpreterPushArgsMode::kWithFinalSpread) {
    // Pass the spread in the register a2.
    // a2 already points to the penultime argument, the spread
    // is below that.
    __ LoadWord(a2, MemOperand(a2, -kSystemPointerSize));
  }
 
  // Call the target.
  if (mode == InterpreterPushArgsMode::kWithFinalSpread) {
    __ TailCallBuiltin(Builtin::kCallWithSpread);
  } else {
    __ TailCallBuiltin(Builtins::Call(receiver_mode));
  }
 
  __ bind(&stack_overflow);
  {
    __ TailCallRuntime(Runtime::kThrowStackOverflow);
    // Unreachable code.
    __ break_(0xCC);
  }
}
 
// static
void Builtins::Generate_InterpreterPushArgsThenConstructImpl(
    MacroAssembler* masm, InterpreterPushArgsMode mode) {
  // ----------- S t a t e -------------
  // -- a0 : argument count
  // -- a3 : new target
  // -- a1 : constructor to call
  // -- a2 : allocation site feedback if available, undefined otherwise.
  // -- a4 : address of the first argument
  // -----------------------------------
  Label stack_overflow;
  __ StackOverflowCheck(a0, a5, t0, &stack_overflow);
 
  if (mode == InterpreterPushArgsMode::kWithFinalSpread) {
    // The spread argument should not be pushed.
    __ SubWord(a0, a0, Operand(1));
  }
  Register argc_without_receiver = a6;
  __ SubWord(argc_without_receiver, a0, Operand(kJSArgcReceiverSlots));
  // Push the arguments, This function modifies a4 and a5.
  GenerateInterpreterPushArgs(masm, argc_without_receiver, a4, a5);
 
  // Push a slot for the receiver.
  __ push(zero_reg);
 
  if (mode == InterpreterPushArgsMode::kWithFinalSpread) {
    // Pass the spread in the register a2.
    // a4 already points to the penultimate argument, the spread
    // lies in the next interpreter register.
    __ LoadWord(a2, MemOperand(a4, -kSystemPointerSize));
  } else {
    __ AssertUndefinedOrAllocationSite(a2, t0);
  }
 
  if (mode == InterpreterPushArgsMode::kArrayFunction) {
    __ AssertFunction(a1);
 
    // Tail call to the function-specific construct stub (still in the caller
    // context at this point).
    __ TailCallBuiltin(Builtin::kArrayConstructorImpl);
  } else if (mode == InterpreterPushArgsMode::kWithFinalSpread) {
    // Call the constructor with a0, a1, and a3 unmodified.
    __ TailCallBuiltin(Builtin::kConstructWithSpread);
  } else {
    DCHECK_EQ(InterpreterPushArgsMode::kOther, mode);
    // Call the constructor with a0, a1, and a3 unmodified.
    __ TailCallBuiltin(Builtin::kConstruct);
  }
 
  __ bind(&stack_overflow);
  {
    __ TailCallRuntime(Runtime::kThrowStackOverflow);
    // Unreachable code.
    __ break_(0xCC);
  }
}
 
// static
void Builtins::Generate_ConstructForwardAllArgsImpl(
    MacroAssembler* masm, ForwardWhichFrame which_frame) {
  // ----------- S t a t e -------------
  // -- a3 : new target
  // -- a1 : constructor to call
  // -----------------------------------
  Label stack_overflow;
 
  // Load the frame pointer into a4.
  switch (which_frame) {
    case ForwardWhichFrame::kCurrentFrame:
      __ Move(a4, fp);
      break;
    case ForwardWhichFrame::kParentFrame:
      __ LoadWord(a4, MemOperand(fp, StandardFrameConstants::kCallerFPOffset));
      break;
  }
 
  // Load the argument count into a0.
  __ LoadWord(a0, MemOperand(a4, StandardFrameConstants::kArgCOffset));
  __ StackOverflowCheck(a0, a5, t0, &stack_overflow);
 
  // Point a4 to the base of the argument list to forward, excluding the
  // receiver.
  __ AddWord(a4, a4,
             Operand((StandardFrameConstants::kFixedSlotCountAboveFp + 1) *
                     kSystemPointerSize));
 
  // Copy arguments on the stack. a5 is a scratch register.
  Register argc_without_receiver = a6;
  __ SubWord(argc_without_receiver, a0, Operand(kJSArgcReceiverSlots));
  __ PushArray(a4, argc_without_receiver);
 
  // Push a slot for the receiver.
  __ push(zero_reg);
 
  // Call the constructor with a0, a1, and a3 unmodified.
  __ TailCallBuiltin(Builtin::kConstruct);
 
  __ bind(&stack_overflow);
  {
    __ TailCallRuntime(Runtime::kThrowStackOverflow);
    // Unreachable code.
    __ break_(0xCC);
  }
}
 
namespace {
 
void NewImplicitReceiver(MacroAssembler* masm) {
  // ----------- S t a t e -------------
  // -- a0 : the number of arguments
  // -- a1 : constructor to call (checked to be a JSFunction)
  // -- a3 : new target
  //
  //  Stack:
  //  -- Implicit Receiver
  //  -- [arguments without receiver]
  //  -- Implicit Receiver
  //  -- Context
  //  -- FastConstructMarker
  //  -- FramePointer
  // -----------------------------------
  Register implicit_receiver = a4;
 
  // Save live registers.
  __ SmiTag(a0);
  __ Push(a0, a1, a3);
  __ CallBuiltin(Builtin::kFastNewObject);
  // Save result.
  __ mv(implicit_receiver, a0);
  __ Pop(a0, a1, a3);
  __ SmiUntag(a0);
 
  // Patch implicit receiver (in arguments)
  __ StoreReceiver(implicit_receiver);
  // Patch second implicit (in construct frame)
  __ StoreWord(
      implicit_receiver,
      MemOperand(fp, FastConstructFrameConstants::kImplicitReceiverOffset));
 
  // Restore context.
  __ LoadWord(cp, MemOperand(fp, FastConstructFrameConstants::kContextOffset));
}
 
}  // namespace
 
// static
void Builtins::Generate_InterpreterPushArgsThenFastConstructFunction(
    MacroAssembler* masm) {
  // ----------- S t a t e -------------
  // -- a0 : argument count
  // -- a1 : constructor to call (checked to be a JSFunction)
  // -- a3 : new target
  // -- a4 : address of the first argument
  // -- cp : context pointer
  // -----------------------------------
  __ AssertFunction(a1);
 
  // Check if target has a [[Construct]] internal method.
  Label non_constructor;
  __ LoadMap(a2, a1);
  __ Lbu(a2, FieldMemOperand(a2, Map::kBitFieldOffset));
  __ And(a2, a2, Operand(Map::Bits1::IsConstructorBit::kMask));
  __ Branch(&non_constructor, eq, a2, Operand(zero_reg));
 
  // Add a stack check before pushing arguments.
  Label stack_overflow;
  __ StackOverflowCheck(a0, a2, a5, &stack_overflow);
 
  // Enter a construct frame.
  FrameScope scope(masm, StackFrame::MANUAL);
  __ EnterFrame(StackFrame::FAST_CONSTRUCT);
 
  // Implicit receiver stored in the construct frame.
  __ LoadRoot(a2, RootIndex::kTheHoleValue);
  __ Push(cp, a2);
 
  // Push arguments + implicit receiver.
  Register argc_without_receiver = a7;
  __ SubWord(argc_without_receiver, a0, Operand(kJSArgcReceiverSlots));
  GenerateInterpreterPushArgs(masm, argc_without_receiver, a4, a5);
  __ Push(a2);
 
  // Check if it is a builtin call.
  Label builtin_call;
  __ LoadTaggedField(
      a2, FieldMemOperand(a1, JSFunction::kSharedFunctionInfoOffset));
  __ Load32U(a2, FieldMemOperand(a2, SharedFunctionInfo::kFlagsOffset));
  __ And(a5, a2, Operand(SharedFunctionInfo::ConstructAsBuiltinBit::kMask));
  __ Branch(&builtin_call, ne, a5, Operand(zero_reg));
 
  // Check if we need to create an implicit receiver.
  Label not_create_implicit_receiver;
  __ DecodeField<SharedFunctionInfo::FunctionKindBits>(a2);
  __ JumpIfIsInRange(
      a2, static_cast<uint32_t>(FunctionKind::kDefaultDerivedConstructor),
      static_cast<uint32_t>(FunctionKind::kDerivedConstructor),
      &not_create_implicit_receiver);
  NewImplicitReceiver(masm);
  __ bind(&not_create_implicit_receiver);
 
  // Call the function.
  __ InvokeFunctionWithNewTarget(a1, a3, a0, InvokeType::kCall);
 
  // ----------- S t a t e -------------
  //  -- x0     constructor result
  //
  //  Stack:
  //  -- Implicit Receiver
  //  -- Context
  //  -- FastConstructMarker
  //  -- FramePointer
  // -----------------------------------
 
  // Store offset of return address for deoptimizer.
  masm->isolate()->heap()->SetConstructStubInvokeDeoptPCOffset(
      masm->pc_offset());
 
  // 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_and_return, check_receiver;
 
  // If the result is undefined, we jump out to using the implicit receiver.
  __ JumpIfNotRoot(a0, RootIndex::kUndefinedValue, &check_receiver);
  // Throw away the result of the constructor invocation and use the
  // on-stack receiver as the result.
  __ bind(&use_receiver);
  __ LoadWord(
      a0, MemOperand(fp, FastConstructFrameConstants::kImplicitReceiverOffset));
  __ JumpIfRoot(a0, RootIndex::kTheHoleValue, &do_throw);
 
  __ bind(&leave_and_return);
  // Leave construct frame.
  __ LeaveFrame(StackFrame::FAST_CONSTRUCT);
  __ Ret();
 
  // Otherwise we do a smi check and fall through to check if the return value
  // is a valid receiver.
  __ bind(&check_receiver);
 
  // If the result is a smi, it is *not* an object in the ECMA sense.
  __ JumpIfSmi(a0, &use_receiver);
 
  // Check if the type of the result is not an object in the ECMA sense.
  __ JumpIfJSAnyIsNotPrimitive(a0, a4, &leave_and_return);
  __ Branch(&use_receiver);
 
  __ bind(&builtin_call);
  // TODO(victorgomes): Check the possibility to turn this into a tailcall.
  __ InvokeFunctionWithNewTarget(a1, a3, a0, InvokeType::kCall);
  __ LeaveFrame(StackFrame::FAST_CONSTRUCT);
  __ Ret();
 
  __ bind(&do_throw);
  // Restore the context from the frame.
  __ LoadWord(cp, MemOperand(fp, FastConstructFrameConstants::kContextOffset));
  __ CallRuntime(Runtime::kThrowConstructorReturnedNonObject);
  // Unreachable code.
  __ Trap();
 
  __ bind(&stack_overflow);
  __ TailCallRuntime(Runtime::kThrowStackOverflow);
  // Unreachable code.
  __ Trap();
 
  // Called Construct on an Object that doesn't have a [[Construct]] internal
  // method.
  __ bind(&non_constructor);
  __ TailCallBuiltin(Builtin::kConstructedNonConstructable);
}
 
static void Generate_InterpreterEnterBytecode(MacroAssembler* masm) {
  // Set the return address to the correct point in the interpreter entry
  // trampoline.
  Label builtin_trampoline, trampoline_loaded;
  Tagged<Smi> interpreter_entry_return_pc_offset(
      masm->isolate()->heap()->interpreter_entry_return_pc_offset());
  DCHECK_NE(interpreter_entry_return_pc_offset, Smi::zero());
 
  // 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.
  __ LoadWord(t0, MemOperand(fp, StandardFrameConstants::kFunctionOffset));
  __ LoadTaggedField(
      t0, FieldMemOperand(t0, JSFunction::kSharedFunctionInfoOffset));
  __ LoadTrustedPointerField(
      t0, FieldMemOperand(t0, SharedFunctionInfo::kTrustedFunctionDataOffset),
      kUnknownIndirectPointerTag);
  __ GetObjectType(t0, kInterpreterDispatchTableRegister,
                   kInterpreterDispatchTableRegister);
  __ Branch(&builtin_trampoline, ne, kInterpreterDispatchTableRegister,
            Operand(INTERPRETER_DATA_TYPE), Label::Distance::kNear);
 
  __ LoadProtectedPointerField(
      t0, FieldMemOperand(t0, InterpreterData::kInterpreterTrampolineOffset));
  __ LoadCodeInstructionStart(t0, t0, kJSEntrypointTag);
  __ BranchShort(&trampoline_loaded);
 
  __ bind(&builtin_trampoline);
  __ li(t0, ExternalReference::
                address_of_interpreter_entry_trampoline_instruction_start(
                    masm->isolate()));
  __ LoadWord(t0, MemOperand(t0));
 
  __ bind(&trampoline_loaded);
  __ AddWord(ra, t0, Operand(interpreter_entry_return_pc_offset.value()));
 
  // Initialize the dispatch table register.
  __ li(kInterpreterDispatchTableRegister,
        ExternalReference::interpreter_dispatch_table_address(masm->isolate()));
 
  // Get the bytecode array pointer from the frame.
  __ LoadWord(kInterpreterBytecodeArrayRegister,
              MemOperand(fp, InterpreterFrameConstants::kBytecodeArrayFromFp));
 
  if (v8_flags.debug_code) {
    // Check function data field is actually a BytecodeArray object.
    __ SmiTst(kInterpreterBytecodeArrayRegister, kScratchReg);
    __ Assert(ne,
              AbortReason::kFunctionDataShouldBeBytecodeArrayOnInterpreterEntry,
              kScratchReg, Operand(zero_reg));
    __ GetObjectType(kInterpreterBytecodeArrayRegister, a1, a1);
    __ Assert(eq,
              AbortReason::kFunctionDataShouldBeBytecodeArrayOnInterpreterEntry,
              a1, Operand(BYTECODE_ARRAY_TYPE));
  }
 
  // Get the target bytecode offset from the frame.
  __ SmiUntag(kInterpreterBytecodeOffsetRegister,
              MemOperand(fp, InterpreterFrameConstants::kBytecodeOffsetFromFp));
 
  if (v8_flags.debug_code) {
    Label okay;
    __ Branch(&okay, ge, kInterpreterBytecodeOffsetRegister,
              Operand(BytecodeArray::kHeaderSize - kHeapObjectTag),
              Label::Distance::kNear);
    // Unreachable code.
    __ break_(0xCC);
    __ bind(&okay);
  }
 
  // Dispatch to the target bytecode.
  __ AddWord(a1, kInterpreterBytecodeArrayRegister,
             kInterpreterBytecodeOffsetRegister);
  __ Lbu(a7, MemOperand(a1));
  __ CalcScaledAddress(a1, kInterpreterDispatchTableRegister, a7,
                       kSystemPointerSizeLog2);
  __ LoadWord(kJavaScriptCallCodeStartRegister, MemOperand(a1));
  __ Jump(kJavaScriptCallCodeStartRegister);
}
 
void Builtins::Generate_InterpreterEnterAtNextBytecode(MacroAssembler* masm) {
  // Advance the current bytecode offset stored within the given interpreter
  // stack frame. This simulates what all bytecode handlers do upon completion
  // of the underlying operation.
  __ LoadWord(kInterpreterBytecodeArrayRegister,
              MemOperand(fp, InterpreterFrameConstants::kBytecodeArrayFromFp));
  __ LoadWord(kInterpreterBytecodeOffsetRegister,
              MemOperand(fp, InterpreterFrameConstants::kBytecodeOffsetFromFp));
  __ SmiUntag(kInterpreterBytecodeOffsetRegister);
 
  Label enter_bytecode, function_entry_bytecode;
  __ Branch(&function_entry_bytecode, eq, kInterpreterBytecodeOffsetRegister,
            Operand(BytecodeArray::kHeaderSize - kHeapObjectTag +
                    kFunctionEntryBytecodeOffset));
 
  // Load the current bytecode.
  __ AddWord(a1, kInterpreterBytecodeArrayRegister,
             kInterpreterBytecodeOffsetRegister);
  __ Lbu(a1, MemOperand(a1));
 
  // Advance to the next bytecode.
  Label if_return;
  AdvanceBytecodeOffsetOrReturn(masm, kInterpreterBytecodeArrayRegister,
                                kInterpreterBytecodeOffsetRegister, a1, a2, a3,
                                a4, &if_return);
 
  __ bind(&enter_bytecode);
  // Convert new bytecode offset to a Smi and save in the stackframe.
  __ SmiTag(a2, kInterpreterBytecodeOffsetRegister);
  __ StoreWord(
      a2, MemOperand(fp, InterpreterFrameConstants::kBytecodeOffsetFromFp));
 
  Generate_InterpreterEnterBytecode(masm);
 
  __ bind(&function_entry_bytecode);
  // If the code deoptimizes during the implicit function entry stack interrupt
  // check, it will have a bailout ID of kFunctionEntryBytecodeOffset, which is
  // not a valid bytecode offset. Detect this case and advance to the first
  // actual bytecode.
  __ li(kInterpreterBytecodeOffsetRegister,
        Operand(BytecodeArray::kHeaderSize - kHeapObjectTag));
  __ Branch(&enter_bytecode);
 
  // We should never take the if_return path.
  __ bind(&if_return);
  __ Abort(AbortReason::kInvalidBytecodeAdvance);
}
 
void Builtins::Generate_InterpreterEnterAtBytecode(MacroAssembler* masm) {
  Generate_InterpreterEnterBytecode(masm);
}
 
namespace {
void Generate_ContinueToBuiltinHelper(MacroAssembler* masm,
                                      bool javascript_builtin,
                                      bool with_result) {
  const RegisterConfiguration* config(RegisterConfiguration::Default());
  int allocatable_register_count = config->num_allocatable_general_registers();
  UseScratchRegisterScope temp(masm);
  Register scratch = temp.Acquire();
  if (with_result) {
    if (javascript_builtin) {
      __ Move(scratch, a0);
    } else {
      // Overwrite the hole inserted by the deoptimizer with the return value
      // from the LAZY deopt point.
      __ StoreWord(
          a0, MemOperand(
                  sp, config->num_allocatable_general_registers() *
                              kSystemPointerSize +
                          BuiltinContinuationFrameConstants::kFixedFrameSize));
    }
  }
  for (int i = allocatable_register_count - 1; i >= 0; --i) {
    int code = config->GetAllocatableGeneralCode(i);
    __ Pop(Register::from_code(code));
    if (javascript_builtin && code == kJavaScriptCallArgCountRegister.code()) {
      __ SmiUntag(Register::from_code(code));
    }
  }
 
  if (with_result && javascript_builtin) {
    // Overwrite the hole inserted by the deoptimizer with the return value from
    // the LAZY deopt point. t0 contains the arguments count, the return value
    // from LAZY is always the last argument.
    constexpr int return_value_offset =
        BuiltinContinuationFrameConstants::kFixedSlotCount -
        kJSArgcReceiverSlots;
    __ AddWord(a0, a0, Operand(return_value_offset));
    __ CalcScaledAddress(t0, sp, a0, kSystemPointerSizeLog2);
    __ StoreWord(scratch, MemOperand(t0));
    // Recover arguments count.
    __ SubWord(a0, a0, Operand(return_value_offset));
  }
 
  __ LoadWord(
      fp,
      MemOperand(sp, BuiltinContinuationFrameConstants::kFixedFrameSizeFromFp));
  // Load builtin index (stored as a Smi) and use it to get the builtin start
  // address from the builtins table.
  __ Pop(t6);
  __ AddWord(sp, sp,
             Operand(BuiltinContinuationFrameConstants::kFixedFrameSizeFromFp));
  __ Pop(ra);
  __ LoadEntryFromBuiltinIndex(t6, t6);
  __ Jump(t6);
}
}  // 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) {
  {
    FrameScope scope(masm, StackFrame::INTERNAL);
    __ CallRuntime(Runtime::kNotifyDeoptimized);
  }
 
  DCHECK_EQ(kInterpreterAccumulatorRegister.code(), a0.code());
  __ LoadWord(a0, MemOperand(sp, 0 * kSystemPointerSize));
  __ AddWord(sp, sp, Operand(1 * kSystemPointerSize));  // Remove state.
  __ Ret();
}
 
namespace {
 
void Generate_OSREntry(MacroAssembler* masm, Register entry_address,
                       Operand offset = Operand(0)) {
  __ AddWord(ra, entry_address, offset);
  // And "return" to the OSR entry point of the function.
  __ Ret();
}
 
enum class OsrSourceTier {
  kInterpreter,
  kBaseline,
};
 
void OnStackReplacement(MacroAssembler* masm, OsrSourceTier source,
                        Register maybe_target_code,
                        Register expected_param_count) {
  Label jump_to_optimized_code;
  {
    // If maybe_target_code is not null, no need to call into runtime. A
    // precondition here is: if maybe_target_code is an InstructionStream
    // object, it must NOT be marked_for_deoptimization (callers must ensure
    // this).
    __ CompareTaggedAndBranch(&jump_to_optimized_code, ne, maybe_target_code,
                              Operand(Smi::zero()));
  }
  ASM_CODE_COMMENT(masm);
  {
    FrameScope scope(masm, StackFrame::INTERNAL);
    __ Push(expected_param_count);
    __ CallRuntime(Runtime::kCompileOptimizedOSR);
    __ Pop(expected_param_count);
  }
 
  // If the code object is null, just return to the caller.
  // If the code object is null, just return to the caller.
  __ CompareTaggedAndBranch(&jump_to_optimized_code, ne, maybe_target_code,
                            Operand(Smi::zero()));
  __ Ret();
  DCHECK_EQ(maybe_target_code, a0);  // Already in the right spot.
 
  __ bind(&jump_to_optimized_code);
 
  const Register scratch(a2);
  CHECK(!AreAliased(maybe_target_code, expected_param_count, scratch));
  // OSR entry tracing.
  {
    Label next;
    __ li(scratch, ExternalReference::address_of_log_or_trace_osr());
    __ Lbu(scratch, MemOperand(scratch));
    __ Branch(&next, eq, scratch, Operand(zero_reg));
 
    {
      FrameScope scope(masm, StackFrame::INTERNAL);
      __ Push(maybe_target_code, expected_param_count);
      __ CallRuntime(Runtime::kLogOrTraceOptimizedOSREntry, 0);
      __ Pop(maybe_target_code, expected_param_count);
    }
 
    __ bind(&next);
  }
 
  if (source == OsrSourceTier::kInterpreter) {
    // 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.
    __ LeaveFrame(StackFrame::STUB);
  }
 
  // Check we are actually jumping to an OSR code object. This among other
  // things ensures that the object contains deoptimization data below.
  __ Load32U(scratch,
             FieldMemOperand(maybe_target_code, Code::kOsrOffsetOffset));
  __ SbxCheck(ne, AbortReason::kExpectedOsrCode, scratch,
              Operand(BytecodeOffset::None().ToInt()));
 
  // Check the target has a matching parameter count. This ensures that the OSR
  // code will correctly tear down our frame when leaving.
  __ Lhu(scratch,
         FieldMemOperand(maybe_target_code, Code::kParameterCountOffset));
  __ SmiUntag(expected_param_count);
  __ SbxCheck(eq, AbortReason::kOsrUnexpectedStackSize, scratch,
              Operand(expected_param_count));
 
  // Load deoptimization data from the code object.
  // <deopt_data> = <code>[#deoptimization_data_offset]
  __ LoadProtectedPointerField(
      scratch,
      FieldMemOperand(maybe_target_code,
                      Code::kDeoptimizationDataOrInterpreterDataOffset));
 
  // Load the OSR entrypoint offset from the deoptimization data.
  // <osr_offset> = <deopt_data>[#header_size + #osr_pc_offset]
  __ SmiUntagField(
      scratch,
      FieldMemOperand(scratch, TrustedFixedArray::OffsetOfElementAt(
                                   DeoptimizationData::kOsrPcOffsetIndex)));
 
  __ LoadCodeInstructionStart(maybe_target_code, maybe_target_code,
                              kJSEntrypointTag);
 
  // Compute the target address = code_entry + osr_offset
  // <entry_addr> = <code_entry> + <osr_offset>
  Generate_OSREntry(masm, maybe_target_code, Operand(scratch));
}
}  // namespace
 
void Builtins::Generate_InterpreterOnStackReplacement(MacroAssembler* masm) {
  using D = OnStackReplacementDescriptor;
  static_assert(D::kParameterCount == 2);
  OnStackReplacement(masm, OsrSourceTier::kInterpreter,
                     D::MaybeTargetCodeRegister(),
                     D::ExpectedParameterCountRegister());
}
 
void Builtins::Generate_BaselineOnStackReplacement(MacroAssembler* masm) {
  using D = OnStackReplacementDescriptor;
  static_assert(D::kParameterCount == 2);
 
  __ LoadWord(kContextRegister,
              MemOperand(fp, BaselineFrameConstants::kContextOffset));
  OnStackReplacement(masm, OsrSourceTier::kBaseline,
                     D::MaybeTargetCodeRegister(),
                     D::ExpectedParameterCountRegister());
}
 
#ifdef V8_ENABLE_MAGLEV
 
void Builtins::Generate_MaglevFunctionEntryStackCheck(MacroAssembler* masm,
                                                      bool save_new_target) {
  // Input (a0): Stack size (Smi).
  // This builtin can be invoked just after Maglev's prologue.
  // All registers are available, except (possibly) new.target.
  Register stack_size = kCArgRegs[0];
  ASM_CODE_COMMENT(masm);
  {
    FrameScope scope(masm, StackFrame::INTERNAL);
    __ AssertSmi(stack_size);
    if (save_new_target) {
      if (PointerCompressionIsEnabled()) {
        __ AssertSmiOrHeapObjectInMainCompressionCage(
            kJavaScriptCallNewTargetRegister);
      }
      __ Push(kJavaScriptCallNewTargetRegister);
    }
    __ Push(stack_size);
    __ CallRuntime(Runtime::kStackGuardWithGap, 1);
    if (save_new_target) {
      __ Pop(kJavaScriptCallNewTargetRegister);
    }
  }
  __ Ret();
}
 
#endif  // V8_ENABLE_MAGLEV
 
// static
void Builtins::Generate_FunctionPrototypeApply(MacroAssembler* masm) {
  // ----------- S t a t e -------------
  //  -- a0    : argc
  //  -- sp[0] : receiver
  //  -- sp[4] : thisArg
  //  -- sp[8] : argArray
  // -----------------------------------
 
  Register argc = a0;
  Register arg_array = a2;
  Register receiver = a1;
  Register this_arg = a5;
  Register undefined_value = a3;
  Register scratch = a4;
 
  __ LoadRoot(undefined_value, RootIndex::kUndefinedValue);
 
  // 1. Load receiver into a1, argArray into a2 (if present), remove all
  // arguments from the stack (including the receiver), and push thisArg (if
  // present) instead.
  {
    // Claim (2 - argc) dummy arguments form the stack, to put the stack in a
    // consistent state for a simple pop operation.
    __ LoadWord(this_arg, MemOperand(sp, kSystemPointerSize));
    __ LoadWord(arg_array, MemOperand(sp, 2 * kSystemPointerSize));
    __ SubWord(scratch, argc, JSParameterCount(0));
    if (CpuFeatures::IsSupported(ZICOND)) {
      __ MoveIfZero(arg_array, undefined_value, scratch);  // if argc == 0
      __ MoveIfZero(this_arg, undefined_value, scratch);   // if argc == 0
      __ SubWord(scratch, scratch, Operand(1));
      __ MoveIfZero(arg_array, undefined_value, scratch);  // if argc == 1
    } else {
      Label done0, done1;
      __ Branch(&done0, ne, scratch, Operand(zero_reg), Label::Distance::kNear);
      __ Move(arg_array, undefined_value);  // if argc == 0
      __ Move(this_arg, undefined_value);   // if argc == 0
      __ bind(&done0);                      // else (i.e., argc > 0)
 
      __ Branch(&done1, ne, scratch, Operand(1), Label::Distance::kNear);
      __ Move(arg_array, undefined_value);  // if argc == 1
      __ bind(&done1);                      // else (i.e., argc > 1)
    }
    __ LoadWord(receiver, MemOperand(sp));
    __ DropArgumentsAndPushNewReceiver(argc, this_arg);
  }
 
  // ----------- S t a t e -------------
  //  -- a2    : argArray
  //  -- a1    : receiver
  //  -- a3    : undefined root value
  //  -- sp[0] : 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;
  __ LoadRoot(scratch, RootIndex::kNullValue);
  __ CompareTaggedAndBranch(&no_arguments, eq, arg_array, Operand(scratch));
  __ CompareTaggedAndBranch(&no_arguments, eq, arg_array,
                            Operand(undefined_value));
 
  // 4a. Apply the receiver to the given argArray.
  __ TailCallBuiltin(Builtin::kCallWithArrayLike);
 
  // 4b. The argArray is either null or undefined, so we tail call without any
  // arguments to the receiver.
  __ bind(&no_arguments);
  {
    __ li(a0, JSParameterCount(0));
    DCHECK(receiver == a1);
    __ TailCallBuiltin(Builtins::Call());
  }
}
 
// static
void Builtins::Generate_FunctionPrototypeCall(MacroAssembler* masm) {
  // 1. Get the callable to call (passed as receiver) from the stack.
  { __ Pop(a1); }
 
  // 2. Make sure we have at least one argument.
  // a0: actual number of arguments
  {
    Label done;
    __ Branch(&done, ne, a0, Operand(JSParameterCount(0)),
              Label::Distance::kNear);
    __ PushRoot(RootIndex::kUndefinedValue);
    __ AddWord(a0, a0, Operand(1));
    __ bind(&done);
  }
 
  // 3. Adjust the actual number of arguments.
  __ AddWord(a0, a0, -1);
 
  // 4. Call the callable.
  __ TailCallBuiltin(Builtins::Call());
}
 
void Builtins::Generate_ReflectApply(MacroAssembler* masm) {
  // ----------- S t a t e -------------
  //  -- a0     : argc
  //  -- sp[0]  : receiver
  //  -- sp[8]  : target         (if argc >= 1)
  //  -- sp[16] : thisArgument   (if argc >= 2)
  //  -- sp[24] : argumentsList  (if argc == 3)
  // -----------------------------------
 
  Register argc = a0;
  Register arguments_list = a2;
  Register target = a1;
  Register this_argument = a5;
  Register undefined_value = a3;
 
  __ LoadRoot(undefined_value, RootIndex::kUndefinedValue);
 
  // 1. Load target into a1 (if present), argumentsList into a2 (if present),
  // remove all arguments from the stack (including the receiver), and push
  // thisArgument (if present) instead.
  {
    // Claim (3 - argc) dummy arguments form the stack, to put the stack in a
    // consistent state for a simple pop operation.
 
    __ LoadWord(target, MemOperand(sp, kSystemPointerSize));
    __ LoadWord(this_argument, MemOperand(sp, 2 * kSystemPointerSize));
    __ LoadWord(arguments_list, MemOperand(sp, 3 * kSystemPointerSize));
 
    UseScratchRegisterScope temps(masm);
    Register scratch = temps.Acquire();
    __ SubWord(scratch, argc, Operand(JSParameterCount(0)));
    if (CpuFeatures::IsSupported(ZICOND)) {
      __ MoveIfZero(arguments_list, undefined_value, scratch);  // if argc == 0
      __ MoveIfZero(this_argument, undefined_value, scratch);   // if argc == 0
      __ MoveIfZero(target, undefined_value, scratch);          // if argc == 0
      __ SubWord(scratch, scratch, Operand(1));
      __ MoveIfZero(arguments_list, undefined_value, scratch);  // if argc == 1
      __ MoveIfZero(this_argument, undefined_value, scratch);   // if argc == 1
      __ SubWord(scratch, scratch, Operand(1));
      __ MoveIfZero(arguments_list, undefined_value, scratch);  // if argc == 2
    } else {
      Label done0, done1, done2;
      __ Branch(&done0, ne, scratch, Operand(zero_reg), Label::Distance::kNear);
      __ Move(arguments_list, undefined_value);  // if argc == 0
      __ Move(this_argument, undefined_value);   // if argc == 0
      __ Move(target, undefined_value);          // if argc == 0
      __ bind(&done0);                           // argc != 0
 
      __ Branch(&done1, ne, scratch, Operand(1), Label::Distance::kNear);
      __ Move(arguments_list, undefined_value);  // if argc == 1
      __ Move(this_argument, undefined_value);   // if argc == 1
      __ bind(&done1);                           // argc > 1
 
      __ Branch(&done2, ne, scratch, Operand(2), Label::Distance::kNear);
      __ Move(arguments_list, undefined_value);  // if argc == 2
      __ bind(&done2);                           // argc > 2
    }
 
    __ DropArgumentsAndPushNewReceiver(argc, this_argument);
  }
 
  // ----------- S t a t e -------------
  //  -- a2    : argumentsList
  //  -- a1    : target
  //  -- a3    : undefined root value
  //  -- sp[0] : 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.
  __ TailCallBuiltin(Builtin::kCallWithArrayLike);
}
 
void Builtins::Generate_ReflectConstruct(MacroAssembler* masm) {
  // ----------- S t a t e -------------
  //  -- a0     : argc
  //  -- sp[0]   : receiver
  //  -- sp[8]   : target
  //  -- sp[16]  : argumentsList
  //  -- sp[24]  : new.target (optional)
  // -----------------------------------
  Register argc = a0;
  Register arguments_list = a2;
  Register target = a1;
  Register new_target = a3;
  Register undefined_value = a4;
 
  __ LoadRoot(undefined_value, RootIndex::kUndefinedValue);
 
  // 1. Load target into a1 (if present), argumentsList into a2 (if present),
  // new.target into a3 (if present, otherwise use target), remove all
  // arguments from the stack (including the receiver), and push thisArgument
  // (if present) instead.
  {
    // Claim (3 - argc) dummy arguments form the stack, to put the stack in a
    // consistent state for a simple pop operation.
    __ LoadWord(target, MemOperand(sp, kSystemPointerSize));
    __ LoadWord(arguments_list, MemOperand(sp, 2 * kSystemPointerSize));
    __ LoadWord(new_target, MemOperand(sp, 3 * kSystemPointerSize));
 
    UseScratchRegisterScope temps(masm);
    Register scratch = temps.Acquire();
    __ SubWord(scratch, argc, Operand(JSParameterCount(0)));
    if (CpuFeatures::IsSupported(ZICOND)) {
      __ MoveIfZero(arguments_list, undefined_value, scratch);  // if argc == 0
      __ MoveIfZero(new_target, undefined_value, scratch);      // if argc == 0
      __ MoveIfZero(target, undefined_value, scratch);          // if argc == 0
      __ SubWord(scratch, scratch, Operand(1));
      __ MoveIfZero(arguments_list, undefined_value, scratch);  // if argc == 1
      __ MoveIfZero(new_target, target, scratch);               // if argc == 1
      __ SubWord(scratch, scratch, Operand(1));
      __ MoveIfZero(new_target, target, scratch);  // if argc == 2
    } else {
      Label done0, done1, done2;
      __ Branch(&done0, ne, scratch, Operand(zero_reg), Label::Distance::kNear);
      __ Move(arguments_list, undefined_value);  // if argc == 0
      __ Move(new_target, undefined_value);      // if argc == 0
      __ Move(target, undefined_value);          // if argc == 0
      __ bind(&done0);
 
      __ Branch(&done1, ne, scratch, Operand(1), Label::Distance::kNear);
      __ Move(arguments_list, undefined_value);  // if argc == 1
      __ Move(new_target, target);               // if argc == 1
      __ bind(&done1);
 
      __ Branch(&done2, ne, scratch, Operand(2), Label::Distance::kNear);
      __ Move(new_target, target);  // if argc == 2
      __ bind(&done2);
    }
 
    __ DropArgumentsAndPushNewReceiver(argc, undefined_value);
  }
 
  // ----------- S t a t e -------------
  //  -- a2    : argumentsList
  //  -- a1    : target
  //  -- a3    : new.target
  //  -- sp[0] : 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.
  __ TailCallBuiltin(Builtin::kConstructWithArrayLike);
}
 
namespace {
 
// Allocate new stack space for |count| arguments and shift all existing
// arguments already on the stack. |pointer_to_new_space_out| points to the
// first free slot on the stack to copy additional arguments to and
// |argc_in_out| is updated to include |count|.
void Generate_AllocateSpaceAndShiftExistingArguments(
    MacroAssembler* masm, Register count, Register argc_in_out,
    Register pointer_to_new_space_out) {
  UseScratchRegisterScope temps(masm);
  Register scratch1 = temps.Acquire();
  Register scratch2 = temps.Acquire();
  Register scratch3 = temps.Acquire();
  DCHECK(!AreAliased(count, argc_in_out, pointer_to_new_space_out, scratch1,
                     scratch2));
  Register old_sp = scratch1;
  Register new_space = scratch2;
  __ mv(old_sp, sp);
  __ slli(new_space, count, kSystemPointerSizeLog2);
  __ SubWord(sp, sp, Operand(new_space));
 
  Register end = scratch2;
  Register value = scratch3;
  Register dest = pointer_to_new_space_out;
  __ mv(dest, sp);
  __ CalcScaledAddress(end, old_sp, argc_in_out, kSystemPointerSizeLog2);
  Label loop, done;
  __ Branch(&done, ge, old_sp, Operand(end));
  __ bind(&loop);
  __ LoadWord(value, MemOperand(old_sp, 0));
  __ StoreWord(value, MemOperand(dest, 0));
  __ AddWord(old_sp, old_sp, Operand(kSystemPointerSize));
  __ AddWord(dest, dest, Operand(kSystemPointerSize));
  __ Branch(&loop, lt, old_sp, Operand(end));
  __ bind(&done);
 
  // Update total number of arguments.
  __ AddWord(argc_in_out, argc_in_out, count);
}
 
}  // namespace
 
// static
void Builtins::Generate_CallOrConstructVarargs(MacroAssembler* masm,
                                               Builtin target_builtin) {
  UseScratchRegisterScope temps(masm);
  temps.Include(t1, t0);
  // ----------- S t a t e -------------
  //  -- a1 : target
  //  -- a0 : number of parameters on the stack
  //  -- a2 : arguments list (a FixedArray)
  //  -- a4 : len (number of elements to push from args)
  //  -- a3 : new.target (for [[Construct]])
  // -----------------------------------
  if (v8_flags.debug_code) {
    // Allow a2 to be a FixedArray, or a FixedDoubleArray if a4 == 0.
    Label ok, fail;
    __ AssertNotSmi(a2);
    __ GetObjectType(a2, kScratchReg, kScratchReg);
    __ Branch(&ok, eq, kScratchReg, Operand(FIXED_ARRAY_TYPE),
              Label::Distance::kNear);
    __ Branch(&fail, ne, kScratchReg, Operand(FIXED_DOUBLE_ARRAY_TYPE),
              Label::Distance::kNear);
    __ Branch(&ok, eq, a4, Operand(zero_reg), Label::Distance::kNear);
    // Fall through.
    __ bind(&fail);
    __ Abort(AbortReason::kOperandIsNotAFixedArray);
 
    __ bind(&ok);
  }
 
  Register args = a2;
  Register len = a4;
 
  // Check for stack overflow.
  Label stack_overflow;
  __ StackOverflowCheck(len, kScratchReg, a5, &stack_overflow);
 
  // Move the arguments already in the stack,
  // including the receiver and the return address.
  // a4: Number of arguments to make room for.
  // a0: Number of arguments already on the stack.
  // a7: Points to first free slot on the stack after arguments were shifted.
  Generate_AllocateSpaceAndShiftExistingArguments(masm, a4, a0, a7);
 
  // Push arguments onto the stack (thisArgument is already on the stack).
  {
    Label done, push, loop;
    Register src = a6;
    Register scratch = len;
    UseScratchRegisterScope temps(masm);
    __ AddWord(src, args, OFFSET_OF_DATA_START(FixedArray) - kHeapObjectTag);
    __ Branch(&done, eq, len, Operand(zero_reg), Label::Distance::kNear);
    __ SllWord(scratch, len, kTaggedSizeLog2);
    __ SubWord(scratch, sp, Operand(scratch));
#if !V8_STATIC_ROOTS_BOOL
    // We do not use the Branch(reg, RootIndex) macro without static roots,
    // as it would do a LoadRoot behind the scenes and we want to avoid that
    // in a loop.
    Register hole_value = temps.Acquire();
    __ LoadTaggedRoot(hole_value, RootIndex::kTheHoleValue);
#endif  // !V8_STATIC_ROOTS_BOOL
    __ bind(&loop);
    __ LoadTaggedField(a5, MemOperand(src));
    __ AddWord(src, src, kTaggedSize);
#if V8_STATIC_ROOTS_BOOL
    __ CompareRootAndBranch(a5, RootIndex::kTheHoleValue, ne, &push);
#else
    __ CompareTaggedAndBranch(&push, ne, a5, Operand(hole_value));
#endif
    __ LoadRoot(a5, RootIndex::kUndefinedValue);
    __ bind(&push);
    __ StoreWord(a5, MemOperand(a7, 0));
    __ AddWord(a7, a7, Operand(kSystemPointerSize));
    __ AddWord(scratch, scratch, Operand(kTaggedSize));
    __ Branch(&loop, ne, scratch, Operand(sp));
    __ bind(&done);
  }
 
  // Tail-call to the actual Call or Construct builtin.
  __ TailCallBuiltin(target_builtin);
 
  __ bind(&stack_overflow);
  __ TailCallRuntime(Runtime::kThrowStackOverflow);
}
 
// static
void Builtins::Generate_CallOrConstructForwardVarargs(MacroAssembler* masm,
                                                      CallOrConstructMode mode,
                                                      Builtin target_builtin) {
  // ----------- S t a t e -------------
  //  -- a0 : the number of arguments
  //  -- a3 : the new.target (for [[Construct]] calls)
  //  -- a1 : the target to call (can be any Object)
  //  -- a2 : start index (to support rest parameters)
  // -----------------------------------
  UseScratchRegisterScope temps(masm);
  temps.Include(t0, t1);
  temps.Include(t2);
  // Check if new.target has a [[Construct]] internal method.
  if (mode == CallOrConstructMode::kConstruct) {
    Label new_target_constructor, new_target_not_constructor;
    UseScratchRegisterScope temps(masm);
    Register scratch = temps.Acquire();
    __ JumpIfSmi(a3, &new_target_not_constructor);
    __ LoadTaggedField(scratch, FieldMemOperand(a3, HeapObject::kMapOffset));
    __ Lbu(scratch, FieldMemOperand(scratch, Map::kBitFieldOffset));
    __ And(scratch, scratch, Operand(Map::Bits1::IsConstructorBit::kMask));
    __ Branch(&new_target_constructor, ne, scratch, Operand(zero_reg),
              Label::Distance::kNear);
    __ bind(&new_target_not_constructor);
    {
      FrameScope scope(masm, StackFrame::MANUAL);
      __ EnterFrame(StackFrame::INTERNAL);
      __ Push(a3);
      __ CallRuntime(Runtime::kThrowNotConstructor);
    }
    __ bind(&new_target_constructor);
  }
 
  __ Move(a6, fp);
  __ LoadWord(a7, MemOperand(fp, StandardFrameConstants::kArgCOffset));
 
  Label stack_done, stack_overflow;
  __ SubWord(a7, a7, Operand(kJSArgcReceiverSlots));
  __ SubWord(a7, a7, a2);
  __ Branch(&stack_done, le, a7, Operand(zero_reg));
  {
    // Check for stack overflow.
    __ StackOverflowCheck(a7, a4, a5, &stack_overflow);
 
    // Forward the arguments from the caller frame.
 
    // Point to the first argument to copy (skipping the receiver).
    __ AddWord(a6, a6,
               Operand(CommonFrameConstants::kFixedFrameSizeAboveFp +
                       kSystemPointerSize));
    __ CalcScaledAddress(a6, a6, a2, kSystemPointerSizeLog2);
 
    // Move the arguments already in the stack,
    // including the receiver and the return address.
    // a7: Number of arguments to make room for.
    // a0: Number of arguments already on the stack.
    // a2: Points to first free slot on the stack after arguments were shifted.
    Generate_AllocateSpaceAndShiftExistingArguments(masm, a7, a0, a2);
 
    // Copy arguments from the caller frame.
    // TODO(victorgomes): Consider using forward order as potentially more cache
    // friendly.
    {
      Label loop;
      __ bind(&loop);
      {
        UseScratchRegisterScope temps(masm);
        Register scratch = temps.Acquire(), addr = temps.Acquire();
        __ Sub32(a7, a7, Operand(1));
        __ CalcScaledAddress(addr, a6, a7, kSystemPointerSizeLog2);
        __ LoadWord(scratch, MemOperand(addr));
        __ CalcScaledAddress(addr, a2, a7, kSystemPointerSizeLog2);
        __ StoreWord(scratch, MemOperand(addr));
        __ Branch(&loop, ne, a7, Operand(zero_reg));
      }
    }
  }
  __ bind(&stack_done);
  // Tail-call to the actual Call or Construct builtin.
  __ TailCallBuiltin(target_builtin);
 
  __ bind(&stack_overflow);
  __ TailCallRuntime(Runtime::kThrowStackOverflow);
}
 
// static
void Builtins::Generate_CallFunction(MacroAssembler* masm,
                                     ConvertReceiverMode mode) {
  // ----------- S t a t e -------------
  //  -- a0 : the number of arguments
  //  -- a1 : the function to call (checked to be a JSFunction)
  // -----------------------------------
  __ AssertFunction(a1);
 
  __ LoadTaggedField(
      a2, FieldMemOperand(a1, JSFunction::kSharedFunctionInfoOffset));
 
  // 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.
  __ LoadTaggedField(cp, FieldMemOperand(a1, JSFunction::kContextOffset));
  // We need to convert the receiver for non-native sloppy mode functions.
  Label done_convert;
  __ Load32U(a3, FieldMemOperand(a2, SharedFunctionInfo::kFlagsOffset));
  __ And(kScratchReg, a3,
         Operand(SharedFunctionInfo::IsNativeBit::kMask |
                 SharedFunctionInfo::IsStrictBit::kMask));
  __ Branch(&done_convert, ne, kScratchReg, Operand(zero_reg));
  {
    // ----------- S t a t e -------------
    //  -- a0 : the number of arguments
    //  -- a1 : the function to call (checked to be a JSFunction)
    //  -- a2 : the shared function info.
    //  -- cp : the function context.
    // -----------------------------------
 
    if (mode == ConvertReceiverMode::kNullOrUndefined) {
      // Patch receiver to global proxy.
      __ LoadGlobalProxy(a3);
    } else {
      Label convert_to_object, convert_receiver;
      __ LoadReceiver(a3);
      __ JumpIfSmi(a3, &convert_to_object);
      __ JumpIfJSAnyIsNotPrimitive(a3, a4, &done_convert);
      if (mode != ConvertReceiverMode::kNotNullOrUndefined) {
        Label convert_global_proxy;
        __ JumpIfRoot(a3, RootIndex::kUndefinedValue, &convert_global_proxy);
        __ JumpIfNotRoot(a3, RootIndex::kNullValue, &convert_to_object);
        __ bind(&convert_global_proxy);
        {
          // Patch receiver to global proxy.
          __ LoadGlobalProxy(a3);
        }
        __ Branch(&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(a0);
        __ Push(a0, a1);
        __ Move(a0, a3);
        __ Push(cp);
        __ CallBuiltin(Builtin::kToObject);
        __ Pop(cp);
        __ Move(a3, a0);
        __ Pop(a0, a1);
        __ SmiUntag(a0);
      }
      __ LoadTaggedField(
          a2, FieldMemOperand(a1, JSFunction::kSharedFunctionInfoOffset));
      __ bind(&convert_receiver);
    }
    __ StoreReceiver(a3);
  }
  __ bind(&done_convert);
 
  // ----------- S t a t e -------------
  //  -- a0 : the number of arguments
  //  -- a1 : the function to call (checked to be a JSFunction)
  //  -- a2 : the shared function info.
  //  -- cp : the function context.
  // -----------------------------------
#if defined(V8_ENABLE_LEAPTIERING) && defined(V8_TARGET_ARCH_RISCV64)
  __ InvokeFunctionCode(a1, no_reg, a0, InvokeType::kJump);
#else
  __ Lhu(a2,
         FieldMemOperand(a2, SharedFunctionInfo::kFormalParameterCountOffset));
  __ InvokeFunctionCode(a1, no_reg, a2, a0, InvokeType::kJump);
#endif
}
 
namespace {
 
void Generate_PushBoundArguments(MacroAssembler* masm) {
  // ----------- S t a t e -------------
  //  -- a0 : the number of arguments
  //  -- a1 : target (checked to be a JSBoundFunction)
  //  -- a3 : new.target (only in case of [[Construct]])
  // -----------------------------------
  UseScratchRegisterScope temps(masm);
  temps.Include(t0, t1);
  Register bound_argc = a4;
  Register bound_argv = a2;
  // Load [[BoundArguments]] into a2 and length of that into a4.
  Label no_bound_arguments;
  __ LoadTaggedField(
      bound_argv, FieldMemOperand(a1, JSBoundFunction::kBoundArgumentsOffset));
  __ SmiUntagField(bound_argc,
                   FieldMemOperand(bound_argv, offsetof(FixedArray, length_)));
  __ Branch(&no_bound_arguments, eq, bound_argc, Operand(zero_reg));
  {
    // ----------- S t a t e -------------
    //  -- a0 : the number of arguments
    //  -- a1 : target (checked to be a JSBoundFunction)
    //  -- a2 : the [[BoundArguments]] (implemented as FixedArray)
    //  -- a3 : new.target (only in case of [[Construct]])
    //  -- a4: the number of [[BoundArguments]]
    // -----------------------------------
    UseScratchRegisterScope temps(masm);
    Register scratch = temps.Acquire();
    Label done;
    // Reserve stack space for the [[BoundArguments]].
    {
      // 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".
      __ StackOverflowCheck(a4, temps.Acquire(), temps.Acquire(), nullptr,
                            &done);
      {
        FrameScope scope(masm, StackFrame::MANUAL);
        __ EnterFrame(StackFrame::INTERNAL);
        __ CallRuntime(Runtime::kThrowStackOverflow);
      }
      __ bind(&done);
    }
 
    // Pop receiver.
    __ Pop(scratch);
 
    // Push [[BoundArguments]].
    {
      Label loop, done_loop;
      __ SmiUntag(a4, FieldMemOperand(a2, offsetof(FixedArray, length_)));
      __ AddWord(a0, a0, Operand(a4));
      __ AddWord(a2, a2,
                 Operand(OFFSET_OF_DATA_START(FixedArray) - kHeapObjectTag));
      __ bind(&loop);
      __ SubWord(a4, a4, Operand(1));
      __ Branch(&done_loop, lt, a4, Operand(zero_reg), Label::Distance::kNear);
      __ CalcScaledAddress(a5, a2, a4, kTaggedSizeLog2);
      __ LoadTaggedField(kScratchReg, MemOperand(a5));
      __ Push(kScratchReg);
      __ Branch(&loop);
      __ bind(&done_loop);
    }
 
    // Push receiver.
    __ Push(scratch);
  }
  __ bind(&no_bound_arguments);
}
 
}  // namespace
 
// static
void Builtins::Generate_CallBoundFunctionImpl(MacroAssembler* masm) {
  // ----------- S t a t e -------------
  //  -- a0 : the number of arguments
  //  -- a1 : the function to call (checked to be a JSBoundFunction)
  // -----------------------------------
  __ AssertBoundFunction(a1);
 
  // Patch the receiver to [[BoundThis]].
  {
    UseScratchRegisterScope temps(masm);
    Register scratch = temps.Acquire();
    __ LoadTaggedField(scratch,
                       FieldMemOperand(a1, JSBoundFunction::kBoundThisOffset));
    __ StoreReceiver(scratch);
  }
 
  // Push the [[BoundArguments]] onto the stack.
  Generate_PushBoundArguments(masm);
 
  // Call the [[BoundTargetFunction]] via the Call builtin.
  __ LoadTaggedField(
      a1, FieldMemOperand(a1, JSBoundFunction::kBoundTargetFunctionOffset));
  __ TailCallBuiltin(Builtins::Call());
}
 
// static
void Builtins::Generate_Call(MacroAssembler* masm, ConvertReceiverMode mode) {
  // ----------- S t a t e -------------
  //  -- a0 : the number of arguments
  //  -- a1 : the target to call (can be any Object).
  // -----------------------------------
 
  Register target = a1;
  Register map = t1;
  Register instance_type = t2;
  Register scratch = t6;
  DCHECK(!AreAliased(a0, target, map, instance_type, scratch));
 
  Label non_callable, class_constructor;
  __ JumpIfSmi(target, &non_callable);
  __ LoadMap(map, target);
  __ GetInstanceTypeRange(map, instance_type, FIRST_CALLABLE_JS_FUNCTION_TYPE,
                          scratch);
  __ TailCallBuiltin(Builtins::CallFunction(mode), ule, scratch,
                     Operand(LAST_CALLABLE_JS_FUNCTION_TYPE -
                             FIRST_CALLABLE_JS_FUNCTION_TYPE));
  __ TailCallBuiltin(Builtin::kCallBoundFunction, eq, instance_type,
                     Operand(JS_BOUND_FUNCTION_TYPE));
 
  // Check if target has a [[Call]] internal method.
  {
    Register flags = t1;
    __ Lbu(flags, FieldMemOperand(map, Map::kBitFieldOffset));
    map = no_reg;
    __ And(flags, flags, Operand(Map::Bits1::IsCallableBit::kMask));
    __ Branch(&non_callable, eq, flags, Operand(zero_reg));
  }
 
  __ TailCallBuiltin(Builtin::kCallProxy, eq, instance_type,
                     Operand(JS_PROXY_TYPE));
 
  // Check if target is a wrapped function and call CallWrappedFunction external
  // builtin
  __ TailCallBuiltin(Builtin::kCallWrappedFunction, eq, instance_type,
                     Operand(JS_WRAPPED_FUNCTION_TYPE));
 
  // ES6 section 9.2.1 [[Call]] ( thisArgument, argumentsList)
  // Check that the function is not a "classConstructor".
  __ Branch(&class_constructor, eq, instance_type,
            Operand(JS_CLASS_CONSTRUCTOR_TYPE));
 
  // 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.
  __ StoreReceiver(target);
  // Let the "call_as_function_delegate" take care of the rest.
  __ LoadNativeContextSlot(target, Context::CALL_AS_FUNCTION_DELEGATE_INDEX);
  __ TailCallBuiltin(
      Builtins::CallFunction(ConvertReceiverMode::kNotNullOrUndefined));
 
  // 3. Call to something that is not callable.
  __ bind(&non_callable);
  {
    FrameScope scope(masm, StackFrame::INTERNAL);
    __ Push(target);
    __ CallRuntime(Runtime::kThrowCalledNonCallable);
  }
 
  // 4. The function is a "classConstructor", need to raise an exception.
  __ bind(&class_constructor);
  {
    FrameScope frame(masm, StackFrame::INTERNAL);
    __ Push(target);
    __ CallRuntime(Runtime::kThrowConstructorNonCallableError);
  }
}
 
void Builtins::Generate_ConstructFunction(MacroAssembler* masm) {
  // ----------- S t a t e -------------
  //  -- a0 : the number of arguments
  //  -- a1 : the constructor to call (checked to be a JSFunction)
  //  -- a3 : the new target (checked to be a constructor)
  // -----------------------------------
  __ AssertConstructor(a1);
  __ AssertFunction(a1);
 
  // Calling convention for function specific ConstructStubs require
  // a2 to contain either an AllocationSite or undefined.
  __ LoadRoot(a2, RootIndex::kUndefinedValue);
 
  Label call_generic_stub;
 
  // Jump to JSBuiltinsConstructStub or JSConstructStubGeneric.
  __ LoadTaggedField(
      a4, FieldMemOperand(a1, JSFunction::kSharedFunctionInfoOffset));
  __ Load32U(a4, FieldMemOperand(a4, SharedFunctionInfo::kFlagsOffset));
  __ And(a4, a4, Operand(SharedFunctionInfo::ConstructAsBuiltinBit::kMask));
  __ Branch(&call_generic_stub, eq, a4, Operand(zero_reg),
            Label::Distance::kNear);
 
  __ TailCallBuiltin(Builtin::kJSBuiltinsConstructStub);
 
  __ bind(&call_generic_stub);
  __ TailCallBuiltin(Builtin::kJSConstructStubGeneric);
}
 
// static
void Builtins::Generate_ConstructBoundFunction(MacroAssembler* masm) {
  // ----------- S t a t e -------------
  //  -- a0 : the number of arguments
  //  -- a1 : the function to call (checked to be a JSBoundFunction)
  //  -- a3 : the new target (checked to be a constructor)
  // -----------------------------------
  __ AssertBoundFunction(a1);
 
  // Push the [[BoundArguments]] onto the stack.
  Generate_PushBoundArguments(masm);
 
  // Patch new.target to [[BoundTargetFunction]] if new.target equals target.
  Label skip;
  __ CompareTaggedAndBranch(&skip, ne, a1, Operand(a3));
  __ LoadTaggedField(
      a3, FieldMemOperand(a1, JSBoundFunction::kBoundTargetFunctionOffset));
  __ bind(&skip);
 
  // Construct the [[BoundTargetFunction]] via the Construct builtin.
  __ LoadTaggedField(
      a1, FieldMemOperand(a1, JSBoundFunction::kBoundTargetFunctionOffset));
  __ TailCallBuiltin(Builtin::kConstruct);
}
 
void Builtins::Generate_Construct(MacroAssembler* masm) {
  // ----------- S t a t e -------------
  //  -- a0 : the number of arguments
  //  -- a1 : the constructor to call (can be any Object)
  //  -- a3 : the new target (either the same as the constructor or
  //          the JSFunction on which new was invoked initially)
  // -----------------------------------
 
  Register target = a1;
  Register map = t1;
  Register instance_type = t2;
  Register scratch = t6;
  DCHECK(!AreAliased(a0, target, map, instance_type, scratch));
 
  // Check if target is a Smi.
  Label non_constructor, non_proxy;
  __ JumpIfSmi(target, &non_constructor);
 
  // Check if target has a [[Construct]] internal method.
  __ LoadTaggedField(map, FieldMemOperand(target, HeapObject::kMapOffset));
  {
    Register flags = t3;
    __ Lbu(flags, FieldMemOperand(map, Map::kBitFieldOffset));
    __ And(flags, flags, Operand(Map::Bits1::IsConstructorBit::kMask));
    __ Branch(&non_constructor, eq, flags, Operand(zero_reg));
  }
 
  // Dispatch based on instance type.
  __ GetInstanceTypeRange(map, instance_type, FIRST_JS_FUNCTION_TYPE, scratch);
  __ TailCallBuiltin(Builtin::kConstructFunction, Uless_equal, scratch,
                     Operand(LAST_JS_FUNCTION_TYPE - FIRST_JS_FUNCTION_TYPE));
 
  // Only dispatch to bound functions after checking whether they are
  // constructors.
  __ TailCallBuiltin(Builtin::kConstructBoundFunction, eq, instance_type,
                     Operand(JS_BOUND_FUNCTION_TYPE));
 
  // Only dispatch to proxies after checking whether they are constructors.
  __ Branch(&non_proxy, ne, instance_type, Operand(JS_PROXY_TYPE));
  __ TailCallBuiltin(Builtin::kConstructProxy);
 
  // Called Construct on an exotic Object with a [[Construct]] internal method.
  __ bind(&non_proxy);
  {
    // Overwrite the original receiver with the (original) target.
    __ StoreReceiver(target);
    // Let the "call_as_constructor_delegate" take care of the rest.
    __ LoadNativeContextSlot(target,
                             Context::CALL_AS_CONSTRUCTOR_DELEGATE_INDEX);
    __ TailCallBuiltin(Builtins::CallFunction());
  }
 
  // Called Construct on an Object that doesn't have a [[Construct]] internal
  // method.
  __ bind(&non_constructor);
  __ TailCallBuiltin(Builtin::kConstructedNonConstructable);
}
 
#if V8_ENABLE_WEBASSEMBLY
// Compute register lists for parameters to be saved. We save all parameter
// registers (see wasm-linkage.h). 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.
constexpr RegList kSavedGpRegs = ([]() constexpr {
  static_assert(WasmLiftoffSetupFrameConstants::kNumberOfSavedGpParamRegs ==
                    arraysize(wasm::kGpParamRegisters) - 1,
                "frame size mismatch");
  RegList saved_gp_regs;
  for (Register gp_param_reg : wasm::kGpParamRegisters) {
    saved_gp_regs.set(gp_param_reg);
  }
 
  // The instance data has already been stored in the fixed part of the frame.
  saved_gp_regs.clear(kWasmImplicitArgRegister);
  // All set registers were unique.
  CHECK_EQ(saved_gp_regs.Count(), arraysize(wasm::kGpParamRegisters) - 1);
  CHECK_EQ(WasmLiftoffSetupFrameConstants::kNumberOfSavedGpParamRegs,
           saved_gp_regs.Count());
  return saved_gp_regs;
})();
 
constexpr DoubleRegList kSavedFpRegs = ([]() constexpr {
  static_assert(WasmLiftoffSetupFrameConstants::kNumberOfSavedFpParamRegs ==
                    arraysize(wasm::kFpParamRegisters),
                "frame size mismatch");
  DoubleRegList saved_fp_regs;
  for (DoubleRegister fp_param_reg : wasm::kFpParamRegisters) {
    saved_fp_regs.set(fp_param_reg);
  }
 
  CHECK_EQ(saved_fp_regs.Count(), arraysize(wasm::kFpParamRegisters));
  CHECK_EQ(WasmLiftoffSetupFrameConstants::kNumberOfSavedFpParamRegs,
           saved_fp_regs.Count());
  return saved_fp_regs;
})();
 
// When entering this builtin, we have just created a Wasm stack frame:
//
// [ Wasm instance data ]  <-- sp
// [ WASM frame marker  ]
// [     saved fp       ]  <-- fp
//
// Add the feedback vector to the stack.
//
// [  feedback vector   ]  <-- sp
// [ Wasm instance data ]
// [ WASM frame marker  ]
// [     saved fp       ]  <-- fp
void Builtins::Generate_WasmLiftoffFrameSetup(MacroAssembler* masm) {
  Register func_index = wasm::kLiftoffFrameSetupFunctionReg;
  Register vector = t1;
  Register scratch = t2;
  Label allocate_vector, done;
 
  __ LoadTaggedField(
      vector, FieldMemOperand(kWasmImplicitArgRegister,
                              WasmTrustedInstanceData::kFeedbackVectorsOffset));
  __ CalcScaledAddress(vector, vector, func_index, kTaggedSizeLog2);
  __ LoadTaggedField(vector,
                     FieldMemOperand(vector, OFFSET_OF_DATA_START(FixedArray)));
  __ JumpIfSmi(vector, &allocate_vector);
  __ bind(&done);
  __ Push(vector);
  __ Ret();
 
  __ bind(&allocate_vector);
  // Feedback vector doesn't exist yet. Call the runtime to allocate it.
  // We temporarily change the frame type for this, because we need special
  // handling by the stack walker in case of GC.
  __ li(scratch, StackFrame::TypeToMarker(StackFrame::WASM_LIFTOFF_SETUP));
  __ StoreWord(scratch, MemOperand(fp, TypedFrameConstants::kFrameTypeOffset));
 
  // Save registers.
  __ MultiPush(kSavedGpRegs);
  __ MultiPushFPU(kSavedFpRegs);
  __ Push(ra);
 
  // Arguments to the runtime function: instance data, func_index, and an
  // additional stack slot for the NativeModule.
  __ SmiTag(func_index);
  __ Push(kWasmImplicitArgRegister, func_index, zero_reg);
  __ Move(cp, Smi::zero());
  __ CallRuntime(Runtime::kWasmAllocateFeedbackVector, 3);
  __ mv(vector, kReturnRegister0);
 
  // Restore registers and frame type.
  __ Pop(ra);
  __ MultiPopFPU(kSavedFpRegs);
  __ MultiPop(kSavedGpRegs);
  __ LoadWord(kWasmImplicitArgRegister,
              MemOperand(fp, WasmFrameConstants::kWasmInstanceDataOffset));
  __ li(scratch, StackFrame::TypeToMarker(StackFrame::WASM));
  __ StoreWord(scratch, MemOperand(fp, TypedFrameConstants::kFrameTypeOffset));
  __ Branch(&done);
}
 
void Builtins::Generate_WasmCompileLazy(MacroAssembler* masm) {
  // The function index was put in t0 by the jump table trampoline.
  // Convert to Smi for the runtime call
  __ SmiTag(kWasmCompileLazyFuncIndexRegister);
 
  {
    HardAbortScope hard_abort(masm);  // Avoid calls to Abort.
    FrameScope scope(masm, StackFrame::INTERNAL);
 
    // Save registers that we need to keep alive across the runtime call.
    __ Push(kWasmImplicitArgRegister);
    __ MultiPush(kSavedGpRegs);
    __ MultiPushFPU(kSavedFpRegs);
 
    __ Push(kWasmImplicitArgRegister, kWasmCompileLazyFuncIndexRegister);
    // Initialize the JavaScript context with 0. CEntry will use it to
    // set the current context on the isolate.
    __ Move(kContextRegister, Smi::zero());
    __ CallRuntime(Runtime::kWasmCompileLazy, 2);
 
    __ SmiUntag(s1, a0);  // move return value to s1 since a0 will be restored
                          // to the value before the call
    CHECK(!kSavedGpRegs.has(s1));
 
    // Restore registers.
    __ MultiPopFPU(kSavedFpRegs);
    __ MultiPop(kSavedGpRegs);
    __ Pop(kWasmImplicitArgRegister);
  }
 
  // The runtime function returned the jump table slot offset as a Smi (now in
  // x17). Use that to compute the jump target.
  __ LoadWord(kScratchReg,
              FieldMemOperand(kWasmImplicitArgRegister,
                              WasmTrustedInstanceData::kJumpTableStartOffset));
  __ AddWord(s1, s1, Operand(kScratchReg));
  // Finally, jump to the entrypoint.
  __ Jump(s1);
}
 
void Builtins::Generate_WasmDebugBreak(MacroAssembler* masm) {
  HardAbortScope hard_abort(masm);  // Avoid calls to Abort.
  {
    FrameScope scope(masm, StackFrame::WASM_DEBUG_BREAK);
 
    // Save all parameter registers. They might hold live values, we restore
    // them after the runtime call.
    __ MultiPush(WasmDebugBreakFrameConstants::kPushedGpRegs);
    __ MultiPushFPU(WasmDebugBreakFrameConstants::kPushedFpRegs);
 
    // Initialize the JavaScript context with 0. CEntry will use it to
    // set the current context on the isolate.
    __ Move(cp, Smi::zero());
    __ CallRuntime(Runtime::kWasmDebugBreak, 0);
 
    // Restore registers.
    __ MultiPopFPU(WasmDebugBreakFrameConstants::kPushedFpRegs);
    __ MultiPop(WasmDebugBreakFrameConstants::kPushedGpRegs);
  }
  __ Ret();
}
 
#endif  // V8_ENABLE_WEBASSEMBLY
 
namespace {
void SwitchSimulatorStackLimit(MacroAssembler* masm) {
  if (masm->options().enable_simulator_code) {
    UseScratchRegisterScope temps(masm);
    temps.Exclude(kSimulatorBreakArgument);
    __ RecordComment("-- Set simulator stack limit --");
    __ LoadStackLimit(kSimulatorBreakArgument, StackLimitKind::kRealStackLimit);
    __ break_(kExceptionIsSwitchStackLimit, false);
  }
}
 
static constexpr Register kOldSPRegister = s9;
static constexpr Register kSwitchFlagRegister = s10;
 
void SwitchToTheCentralStackIfNeeded(MacroAssembler* masm, Register argc_input,
                                     Register target_input,
                                     Register argv_input) {
  using ER = ExternalReference;
 
  __ li(kSwitchFlagRegister, 0);
  __ mv(kOldSPRegister, sp);
 
  // Using x2-x4 as temporary registers, because they will be rewritten
  // before exiting to native code anyway.
 
  ER on_central_stack_flag_loc = ER::Create(
      IsolateAddressId::kIsOnCentralStackFlagAddress, masm->isolate());
  const Register& on_central_stack_flag = a2;
  __ li(on_central_stack_flag, on_central_stack_flag_loc);
  __ Lb(on_central_stack_flag, MemOperand(on_central_stack_flag));
 
  Label do_not_need_to_switch;
  __ Branch(&do_not_need_to_switch, ne, on_central_stack_flag,
            Operand(zero_reg));
  // Switch to central stack.
 
  static constexpr Register central_stack_sp = a4;
  DCHECK(!AreAliased(central_stack_sp, argc_input, argv_input, target_input));
  {
    __ Push(argc_input, target_input, argv_input);
    __ PrepareCallCFunction(2, argc_input);
    __ li(kCArgRegs[0], ER::isolate_address(masm->isolate()));
    __ mv(kCArgRegs[1], kOldSPRegister);
    __ CallCFunction(ER::wasm_switch_to_the_central_stack(), 2,
                     SetIsolateDataSlots::kNo);
    __ mv(central_stack_sp, kReturnRegister0);
    __ Pop(argc_input, target_input, argv_input);
  }
 
  SwitchSimulatorStackLimit(masm);
 
  static constexpr int kReturnAddressSlotOffset = 1 * kSystemPointerSize;
  static constexpr int kPadding = 1 * kSystemPointerSize;
  __ SubWord(sp, central_stack_sp, kReturnAddressSlotOffset + kPadding);
 
#ifdef V8_TARGET_ARCH_RISCV32
  __ EnforceStackAlignment();
#endif
  __ li(kSwitchFlagRegister, 1);
 
  // Update the sp saved in the frame.
  // It will be used to calculate the callee pc during GC.
  // The pc is going to be on the new stack segment, so rewrite it here.
  __ AddWord(central_stack_sp, sp, kSystemPointerSize);
  __ StoreWord(central_stack_sp, MemOperand(fp, ExitFrameConstants::kSPOffset));
 
  __ bind(&do_not_need_to_switch);
}
 
void SwitchFromTheCentralStackIfNeeded(MacroAssembler* masm) {
  using ER = ExternalReference;
 
  Label no_stack_change;
  __ Branch(&no_stack_change, eq, kSwitchFlagRegister, Operand(zero_reg));
 
  {
    __ Push(kReturnRegister0, kReturnRegister1);
    __ li(kCArgRegs[0], ER::isolate_address(masm->isolate()));
    DCHECK_NE(kReturnRegister1, kCArgRegs[0]);
    __ PrepareCallCFunction(1, kReturnRegister1);
    __ CallCFunction(ER::wasm_switch_from_the_central_stack(), 1,
                     SetIsolateDataSlots::kNo);
    __ Pop(kReturnRegister0, kReturnRegister1);
  }
 
  SwitchSimulatorStackLimit(masm);
 
  __ mv(sp, kOldSPRegister);
 
  __ bind(&no_stack_change);
}
}  // namespace
 
void Builtins::Generate_CEntry(MacroAssembler* masm, int result_size,
                               ArgvMode argv_mode, bool builtin_exit_frame,
                               bool switch_to_central_stack) {
  // Called from JavaScript; parameters are on stack as if calling JS function
  // a0: number of arguments including receiver
  // a1: pointer to c++ function
  // fp: frame pointer    (restored after C call)
  // sp: stack pointer    (restored as callee's sp after C call)
  // cp: current context  (C callee-saved)
  // If argv_mode == ArgvMode::kRegister:
  // a2: pointer to the first argument
  using ER = ExternalReference;
 
  static constexpr Register argc_input = a0;
  static constexpr Register target_input = a1;
  // Initialized below if ArgvMode::kStack.
  static constexpr Register argv_input = s1;
  static constexpr Register argc_sav = s3;
  static constexpr Register scratch = a3;
  if (argv_mode == ArgvMode::kRegister) {
    // Move argv into the correct register.
    __ Move(s1, a2);
  } else {
    // Compute the argv pointer in a callee-saved register.
    __ CalcScaledAddress(s1, sp, a0, kSystemPointerSizeLog2);
    __ SubWord(s1, s1, kSystemPointerSize);
  }
 
  // Enter the exit frame that transitions from JavaScript to C++.
  FrameScope scope(masm, StackFrame::MANUAL);
  __ EnterExitFrame(
      scratch, 0,
      builtin_exit_frame ? StackFrame::BUILTIN_EXIT : StackFrame::EXIT);
 
  // s3: number of arguments  including receiver (C callee-saved)
  // s1: pointer to first argument (C callee-saved)
  // s2: pointer to builtin function (C callee-saved)
 
  // Prepare arguments for C routine.
  // a0 = argc
  __ Move(argc_sav, argc_input);
  __ Move(s2, target_input);
 
  // We are calling compiled C/C++ code. a0 and a1 hold our two arguments. We
  // also need to reserve the 4 argument slots on the stack.
 
  __ AssertStackIsAligned();
 
#if V8_ENABLE_WEBASSEMBLY
  if (switch_to_central_stack) {
    SwitchToTheCentralStackIfNeeded(masm, argc_input, target_input, argv_input);
  }
#endif  // V8_ENABLE_WEBASSEMBLY
 
  // a0 = argc, a1 = argv, a2 = isolate
  __ li(a2, ER::isolate_address(masm->isolate()));
  __ Move(a1, s1);
 
  __ StoreReturnAddressAndCall(s2);
 
  // Check result for exception sentinel.
  Label exception_returned;
  // The returned value may be a trusted object, living outside of the main
  // pointer compression cage, so we need to use full pointer comparison here.
  __ CompareRootAndBranch(a0, RootIndex::kException, eq, &exception_returned,
                          ComparisonMode::kFullPointer);
 
  // Result returned in a0 or a1:a0 - do not destroy these registers!
#if V8_ENABLE_WEBASSEMBLY
  if (switch_to_central_stack) {
    SwitchFromTheCentralStackIfNeeded(masm);
  }
#endif  // V8_ENABLE_WEBASSEMBLY
  // Exit C frame and return.
  // a0:a1: result
  // sp: stack pointer
  // fp: frame pointer
  // s3: still holds argc (C caller-saved).
  __ LeaveExitFrame(scratch);
  if (argv_mode == ArgvMode::kStack) {
    DCHECK(!AreAliased(scratch, argc_sav));
    __ DropArguments(argc_sav);
  }
  __ Ret();
 
  // Handling of exception.
  __ bind(&exception_returned);
 
  ER pending_handler_context_address = ER::Create(
      IsolateAddressId::kPendingHandlerContextAddress, masm->isolate());
  ER pending_handler_entrypoint_address = ER::Create(
      IsolateAddressId::kPendingHandlerEntrypointAddress, masm->isolate());
  ER pending_handler_fp_address =
      ER::Create(IsolateAddressId::kPendingHandlerFPAddress, masm->isolate());
  ER pending_handler_sp_address =
      ER::Create(IsolateAddressId::kPendingHandlerSPAddress, masm->isolate());
 
  // Ask the runtime for help to determine the handler. This will set a0 to
  // contain the current exception, don't clobber it.
  ER find_handler = ER::Create(Runtime::kUnwindAndFindExceptionHandler);
  {
    FrameScope scope(masm, StackFrame::MANUAL);
    __ PrepareCallCFunction(3, 0, a0);
    __ Move(a0, zero_reg);
    __ Move(a1, zero_reg);
    __ li(a2, ER::isolate_address());
    __ CallCFunction(find_handler, 3, SetIsolateDataSlots::kNo);
  }
 
  // Retrieve the handler context, SP and FP.
  __ li(cp, pending_handler_context_address);
  __ LoadWord(cp, MemOperand(cp));
  __ li(sp, pending_handler_sp_address);
  __ LoadWord(sp, MemOperand(sp));
  __ li(fp, pending_handler_fp_address);
  __ LoadWord(fp, MemOperand(fp));
 
  // If the handler is a JS frame, restore the context to the frame. Note that
  // the context will be set to (cp == 0) for non-JS frames.
  Label zero;
  __ Branch(&zero, eq, cp, Operand(zero_reg), Label::Distance::kNear);
  __ StoreWord(cp, MemOperand(fp, StandardFrameConstants::kContextOffset));
  __ bind(&zero);
 
  // Clear c_entry_fp, like we do in `LeaveExitFrame`.
  ER c_entry_fp_address =
      ER::Create(IsolateAddressId::kCEntryFPAddress, masm->isolate());
  __ StoreWord(zero_reg,
               __ ExternalReferenceAsOperand(c_entry_fp_address, no_reg));
 
  // Compute the handler entry address and jump to it.
  __ LoadWord(scratch, __ ExternalReferenceAsOperand(
                           pending_handler_entrypoint_address, no_reg));
  __ Jump(scratch);
}
 
#if V8_ENABLE_WEBASSEMBLY
void Builtins::Generate_WasmHandleStackOverflow(MacroAssembler* masm) {
  using ER = ExternalReference;
  Register frame_base = WasmHandleStackOverflowDescriptor::FrameBaseRegister();
  Register gap = WasmHandleStackOverflowDescriptor::GapRegister();
  {
    DCHECK_NE(kCArgRegs[1], frame_base);
    DCHECK_NE(kCArgRegs[3], frame_base);
    __ mv(kCArgRegs[3], gap);
    __ mv(kCArgRegs[1], sp);
    __ SubWord(kCArgRegs[2], frame_base, kCArgRegs[1]);
    __ mv(kCArgRegs[4], fp);
    FrameScope scope(masm, StackFrame::INTERNAL);
    __ Push(kCArgRegs[3]);
    __ li(kCArgRegs[0], ER::isolate_address());
    __ PrepareCallCFunction(5, kScratchReg);
    __ CallCFunction(ER::wasm_grow_stack(), 5);
    __ Pop(gap);
    DCHECK_NE(kReturnRegister0, gap);
  }
  Label call_runtime;
  // wasm_grow_stack returns zero if it cannot grow a stack.
  __ BranchShort(&call_runtime, eq, kReturnRegister0, Operand(zero_reg));
  {
    UseScratchRegisterScope temps(masm);
    Register new_fp = temps.Acquire();
    // Calculate old FP - SP offset to adjust FP accordingly to new SP.
    __ SubWord(new_fp, fp, sp);
    __ AddWord(new_fp, kReturnRegister0, new_fp);
    __ mv(fp, new_fp);
  }
  __ mv(sp, kReturnRegister0);
  {
    UseScratchRegisterScope temps(masm);
    Register scratch = temps.Acquire();
    __ li(scratch, StackFrame::TypeToMarker(StackFrame::WASM_SEGMENT_START));
    __ StoreWord(scratch,
                 MemOperand(fp, TypedFrameConstants::kFrameTypeOffset));
  }
  __ Ret();
 
  __ bind(&call_runtime);
  // If wasm_grow_stack returns zero interruption or stack overflow
  // should be handled by runtime call.
  {
    __ LoadWord(kWasmImplicitArgRegister,
                MemOperand(fp, WasmFrameConstants::kWasmInstanceDataOffset));
    __ LoadTaggedField(
        cp, FieldMemOperand(kWasmImplicitArgRegister,
                            WasmTrustedInstanceData::kNativeContextOffset));
    FrameScope scope(masm, StackFrame::MANUAL);
    __ EnterFrame(StackFrame::INTERNAL);
    __ SmiTag(gap);
    __ Push(gap);
    __ CallRuntime(Runtime::kWasmStackGuard);
    __ LeaveFrame(StackFrame::INTERNAL);
    __ Ret();
  }
}
#endif  // V8_ENABLE_WEBASSEMBLY
 
void Builtins::Generate_DoubleToI(MacroAssembler* masm) {
  Label done;
  Register result_reg = t0;
 
  Register scratch = GetRegisterThatIsNotOneOf(result_reg);
  Register scratch2 = GetRegisterThatIsNotOneOf(result_reg, scratch);
  Register scratch3 = GetRegisterThatIsNotOneOf(result_reg, scratch, scratch2);
  DoubleRegister double_scratch = kScratchDoubleReg;
 
  // Account for saved regs.
  const int kArgumentOffset = 4 * kSystemPointerSize;
 
  __ Push(result_reg);
  __ Push(scratch, scratch2, scratch3);
 
  // Load double input.
  __ LoadDouble(double_scratch, MemOperand(sp, kArgumentOffset));
 
  // Try a conversion to a signed integer, if exception occurs, scratch is
  // set to 0
  __ Trunc_w_d(scratch3, double_scratch, scratch);
 
  // If we had no exceptions then set result_reg and we are done.
  Label error;
  __ Branch(&error, eq, scratch, Operand(zero_reg), Label::Distance::kNear);
  __ Move(result_reg, scratch3);
  __ Branch(&done);
  __ bind(&error);
 
  // Load the double value and perform a manual truncation.
  Register input_high = scratch2;
  Register input_low = scratch3;
 
  __ Lw(input_low, MemOperand(sp, kArgumentOffset + Register::kMantissaOffset));
  __ Lw(input_high,
        MemOperand(sp, kArgumentOffset + Register::kExponentOffset));
 
  Label normal_exponent;
  // Extract the biased exponent in result.
  __ ExtractBits(result_reg, input_high, HeapNumber::kExponentShift,
                 HeapNumber::kExponentBits);
 
  // Check for Infinity and NaNs, which should return 0.
  __ Sub32(scratch, result_reg, HeapNumber::kExponentMask);
  __ LoadZeroIfConditionZero(
      result_reg,
      scratch);  // result_reg = scratch == 0 ? 0 : result_reg
  __ Branch(&done, eq, scratch, Operand(zero_reg));
 
  // Express exponent as delta to (number of mantissa bits + 31).
  __ Sub32(result_reg, result_reg,
           Operand(HeapNumber::kExponentBias + HeapNumber::kMantissaBits + 31));
 
  // If the delta is strictly positive, all bits would be shifted away,
  // which means that we can return 0.
  __ Branch(&normal_exponent, le, result_reg, Operand(zero_reg),
            Label::Distance::kNear);
  __ Move(result_reg, zero_reg);
  __ Branch(&done);
 
  __ bind(&normal_exponent);
  const int kShiftBase = HeapNumber::kNonMantissaBitsInTopWord - 1;
  // Calculate shift.
  __ Add32(scratch, result_reg,
           Operand(kShiftBase + HeapNumber::kMantissaBits));
 
  // Save the sign.
  Register sign = result_reg;
  result_reg = no_reg;
  __ And(sign, input_high, Operand(HeapNumber::kSignMask));
 
  // We must specially handle shifts greater than 31.
  Label high_shift_needed, high_shift_done;
  __ Branch(&high_shift_needed, lt, scratch, Operand(32),
            Label::Distance::kNear);
  __ Move(input_high, zero_reg);
  __ BranchShort(&high_shift_done);
  __ bind(&high_shift_needed);
 
  // Set the implicit 1 before the mantissa part in input_high.
  __ Or(input_high, input_high,
        Operand(1 << HeapNumber::kMantissaBitsInTopWord));
  // Shift the mantissa bits to the correct position.
  // We don't need to clear non-mantissa bits as they will be shifted away.
  // If they weren't, it would mean that the answer is in the 32bit range.
  __ Sll32(input_high, input_high, scratch);
 
  __ bind(&high_shift_done);
 
  // Replace the shifted bits with bits from the lower mantissa word.
  Label pos_shift, shift_done, sign_negative;
  __ li(kScratchReg, 32);
  __ Sub32(scratch, kScratchReg, scratch);
  __ Branch(&pos_shift, ge, scratch, Operand(zero_reg), Label::Distance::kNear);
 
  // Negate scratch.
  __ Sub32(scratch, zero_reg, scratch);
  __ Sll32(input_low, input_low, scratch);
  __ BranchShort(&shift_done);
 
  __ bind(&pos_shift);
  __ Srl32(input_low, input_low, scratch);
 
  __ bind(&shift_done);
  __ Or(input_high, input_high, Operand(input_low));
  // Restore sign if necessary.
  __ Move(scratch, sign);
  result_reg = sign;
  sign = no_reg;
  __ Sub32(result_reg, zero_reg, input_high);
  __ Branch(&sign_negative, ne, scratch, Operand(zero_reg),
            Label::Distance::kNear);
  __ Move(result_reg, input_high);
  __ bind(&sign_negative);
 
  __ bind(&done);
 
  __ StoreWord(result_reg, MemOperand(sp, kArgumentOffset));
  __ Pop(scratch, scratch2, scratch3);
  __ Pop(result_reg);
  __ Ret();
}
 
void Builtins::Generate_WasmToJsWrapperAsm(MacroAssembler* masm) {
  int required_stack_space = arraysize(wasm::kFpParamRegisters) * kDoubleSize;
  __ SubWord(sp, sp, Operand(required_stack_space));
  for (int i = 0; i < static_cast<int>(arraysize(wasm::kFpParamRegisters));
       ++i) {
    __ StoreDouble(wasm::kFpParamRegisters[i], MemOperand(sp, i * kDoubleSize));
  }
 
  constexpr int num_gp = arraysize(wasm::kGpParamRegisters) - 1;
  required_stack_space = num_gp * kSystemPointerSize;
  __ SubWord(sp, sp, Operand(required_stack_space));
  for (int i = 1; i < static_cast<int>(arraysize(wasm::kGpParamRegisters));
       ++i) {
    __ StoreWord(wasm::kGpParamRegisters[i],
                 MemOperand(sp, (i - 1) * kSystemPointerSize));
  }
  // Reserve a slot for the signature.
  __ Push(zero_reg);
  __ TailCallBuiltin(Builtin::kWasmToJsWrapperCSA);
}
 
void Builtins::Generate_WasmTrapHandlerLandingPad(MacroAssembler* masm) {
  // This builtin gets called from the WebAssembly trap handler when an
  // out-of-bounds memory access happened or when a null reference gets
  // dereferenced. This builtin then fakes a call from the instruction that
  // triggered the signal to the runtime. This is done by setting a return
  // address and then jumping to a builtin which will call further to the
  // runtime.
  // As the return address we use the fault address + 1. Using the fault address
  // itself would cause problems with safepoints and source positions.
  //
  // The problem with safepoints is that a safepoint has to be registered at the
  // return address, and that at most one safepoint should be registered at a
  // location. However, there could already be a safepoint registered at the
  // fault address if the fault address is the return address of a call.
  //
  // The problem with source positions is that the stack trace code looks for
  // the source position of a call before the return address. The source
  // position of the faulty memory access, however, is recorded at the fault
  // address. Therefore the stack trace code would not find the source position
  // if we used the fault address as the return address.
  __ AddWord(ra, kWasmTrapHandlerFaultAddressRegister, 1);
  __ TailCallBuiltin(Builtin::kWasmTrapHandlerThrowTrap);
}
 
namespace {
// Check that the stack was in the old state (if generated code assertions are
// enabled), and switch to the new state.
void SwitchStackState(MacroAssembler* masm, Register jmpbuf, Register tmp,
                      wasm::JumpBuffer::StackState old_state,
                      wasm::JumpBuffer::StackState new_state) {
  ASM_CODE_COMMENT(masm);
#if V8_ENABLE_SANDBOX
  __ Lw(tmp, MemOperand(jmpbuf, wasm::kJmpBufStateOffset));
  Label ok;
  // is branch32?
  __ Branch(&ok, eq, tmp, Operand(old_state));
  __ Trap();
  __ bind(&ok);
#endif
  __ li(tmp, new_state);
  __ Sw(tmp, MemOperand(jmpbuf, wasm::kJmpBufStateOffset));
}
 
// Switch the stack pointer. Also switch the simulator's stack limit when
// running on the simulator. This needs to be done as close as possible to
// changing the stack pointer, as a mismatch between the stack pointer and the
// simulator's stack limit can cause stack access check failures.
void SwitchStackPointerAndSimulatorStackLimit(MacroAssembler* masm,
                                              Register jmpbuf) {
  ASM_CODE_COMMENT(masm);
  if (masm->options().enable_simulator_code) {
    UseScratchRegisterScope temps(masm);
    temps.Exclude(kSimulatorBreakArgument);
    __ LoadWord(sp, MemOperand(jmpbuf, wasm::kJmpBufSpOffset));
    __ LoadWord(kSimulatorBreakArgument,
                MemOperand(jmpbuf, wasm::kJmpBufStackLimitOffset));
    __ break_(kExceptionIsSwitchStackLimit);
  } else {
    __ LoadWord(sp, MemOperand(jmpbuf, wasm::kJmpBufSpOffset));
  }
}
 
void FillJumpBuffer(MacroAssembler* masm, Register jmpbuf, Label* pc,
                    Register tmp) {
  ASM_CODE_COMMENT(masm);
  __ mv(tmp, sp);
  __ StoreWord(tmp, MemOperand(jmpbuf, wasm::kJmpBufSpOffset));
  __ StoreWord(fp, MemOperand(jmpbuf, wasm::kJmpBufFpOffset));
  __ LoadStackLimit(tmp, StackLimitKind::kRealStackLimit);
  __ StoreWord(tmp, MemOperand(jmpbuf, wasm::kJmpBufStackLimitOffset));
  __ LoadAddress(tmp, pc);
  __ StoreWord(tmp, MemOperand(jmpbuf, wasm::kJmpBufPcOffset));
}
 
void LoadJumpBuffer(MacroAssembler* masm, Register jmpbuf, bool load_pc,
                    Register tmp, wasm::JumpBuffer::StackState expected_state) {
  ASM_CODE_COMMENT(masm);
  SwitchStackPointerAndSimulatorStackLimit(masm, jmpbuf);
  __ LoadWord(fp, MemOperand(jmpbuf, wasm::kJmpBufFpOffset));
  SwitchStackState(masm, jmpbuf, tmp, expected_state, wasm::JumpBuffer::Active);
  if (load_pc) {
    __ LoadWord(tmp, MemOperand(jmpbuf, wasm::kJmpBufPcOffset));
    __ Jump(tmp);
  }
  // The stack limit in StackGuard is set separately under the ExecutionAccess
  // lock.
}
 
// Updates the stack limit and central stack info, and validates the switch.
void SwitchStacks(MacroAssembler* masm, Register old_continuation,
                  bool return_switch, Register tmp,
                  const std::initializer_list<Register> keep) {
  ASM_CODE_COMMENT(masm);
  CHECK(!AreAliased(old_continuation, a0));
  using ER = ExternalReference;
  for (auto reg : keep) {
    __ Push(reg);
  }
  {
    FrameScope scope(masm, StackFrame::MANUAL);
    __ li(kCArgRegs[0], ExternalReference::isolate_address(masm->isolate()));
    __ mv(kCArgRegs[1], old_continuation);
    __ PrepareCallCFunction(2, tmp);
    __ CallCFunction(
        return_switch ? ER::wasm_return_switch() : ER::wasm_switch_stacks(), 2);
  }
  for (auto it = std::rbegin(keep); it != std::rend(keep); ++it) {
    __ Pop(*it);
  }
}
 
void ReloadParentContinuation(MacroAssembler* masm, Register return_reg,
                              Register return_value, Register context,
                              Register tmp1, Register tmp2, Register tmp3) {
  ASM_CODE_COMMENT(masm);
  Register active_continuation = tmp1;
  __ LoadRoot(active_continuation, RootIndex::kActiveContinuation);
 
  // Set a null pointer in the jump buffer's SP slot to indicate to the stack
  // frame iterator that this stack is empty.
  Register jmpbuf = tmp2;
  __ LoadExternalPointerField(
      jmpbuf,
      FieldMemOperand(active_continuation,
                      WasmContinuationObject::kStackOffset),
      kWasmStackMemoryTag);
  __ AddWord(jmpbuf, jmpbuf, wasm::StackMemory::jmpbuf_offset());
  __ StoreWord(zero_reg, MemOperand(jmpbuf, wasm::kJmpBufSpOffset));
  {
    UseScratchRegisterScope temps(masm);
    Register scratch = temps.Acquire();
    SwitchStackState(masm, jmpbuf, scratch, wasm::JumpBuffer::Active,
                     wasm::JumpBuffer::Retired);
  }
  Register parent = tmp2;
  __ LoadTaggedField(parent,
                     FieldMemOperand(active_continuation,
                                     WasmContinuationObject::kParentOffset));
 
  // Update active continuation root.
  int32_t active_continuation_offset =
      MacroAssembler::RootRegisterOffsetForRootIndex(
          RootIndex::kActiveContinuation);
  __ StoreWord(parent, MemOperand(kRootRegister, active_continuation_offset));
  jmpbuf = parent;
  __ LoadExternalPointerField(
      jmpbuf, FieldMemOperand(parent, WasmContinuationObject::kStackOffset),
      kWasmStackMemoryTag);
  __ AddWord(jmpbuf, jmpbuf, wasm::StackMemory::jmpbuf_offset());
 
  // Switch stack!
  SwitchStacks(masm, active_continuation, true, tmp3,
               {return_reg, return_value, context, jmpbuf});
  LoadJumpBuffer(masm, jmpbuf, false, tmp3, wasm::JumpBuffer::Inactive);
}
 
void RestoreParentSuspender(MacroAssembler* masm, Register tmp1,
                            Register tmp2) {
  ASM_CODE_COMMENT(masm);
  Register suspender = tmp1;
  __ LoadRoot(suspender, RootIndex::kActiveSuspender);
  __ LoadTaggedField(
      suspender,
      FieldMemOperand(suspender, WasmSuspenderObject::kParentOffset));
 
  int32_t active_suspender_offset =
      MacroAssembler::RootRegisterOffsetForRootIndex(
          RootIndex::kActiveSuspender);
  __ StoreWord(suspender, MemOperand(kRootRegister, active_suspender_offset));
}
 
class RegisterAllocator {
 public:
  class Scoped {
   public:
    Scoped(RegisterAllocator* allocator, Register* reg)
        : allocator_(allocator), reg_(reg) {}
    ~Scoped() { allocator_->Free(reg_); }
 
   private:
    RegisterAllocator* allocator_;
    Register* reg_;
  };
 
  explicit RegisterAllocator(const RegList& registers)
      : initial_(registers), available_(registers) {}
  void Ask(Register* reg) {
    DCHECK_EQ(*reg, no_reg);
    DCHECK(!available_.is_empty());
    *reg = available_.PopFirst();
    allocated_registers_.push_back(reg);
  }
 
  bool registerIsAvailable(const Register& reg) { return available_.has(reg); }
 
  void Pinned(const Register& requested, Register* reg) {
    if (!registerIsAvailable(requested)) {
      printf("%s register is ocupied!", RegisterName(requested));
    }
    DCHECK(registerIsAvailable(requested));
    *reg = requested;
    Reserve(requested);
    allocated_registers_.push_back(reg);
  }
 
  void Free(Register* reg) {
    DCHECK_NE(*reg, no_reg);
    available_.set(*reg);
    *reg = no_reg;
    allocated_registers_.erase(
        find(allocated_registers_.begin(), allocated_registers_.end(), reg));
  }
 
  void Reserve(const Register& reg) {
    if (reg == no_reg) {
      return;
    }
    DCHECK(registerIsAvailable(reg));
    available_.clear(reg);
  }
 
  void Reserve(const Register& reg1, const Register& reg2,
               const Register& reg3 = no_reg, const Register& reg4 = no_reg,
               const Register& reg5 = no_reg, const Register& reg6 = no_reg) {
    Reserve(reg1);
    Reserve(reg2);
    Reserve(reg3);
    Reserve(reg4);
    Reserve(reg5);
    Reserve(reg6);
  }
 
  bool IsUsed(const Register& reg) {
    return initial_.has(reg) && !registerIsAvailable(reg);
  }
 
  void ResetExcept(const Register& reg1 = no_reg, const Register& reg2 = no_reg,
                   const Register& reg3 = no_reg, const Register& reg4 = no_reg,
                   const Register& reg5 = no_reg,
                   const Register& reg6 = no_reg) {
    available_ = initial_;
    available_.clear(reg1);
    available_.clear(reg2);
    available_.clear(reg3);
    available_.clear(reg4);
    available_.clear(reg5);
    available_.clear(reg6);
 
    auto it = allocated_registers_.begin();
    while (it != allocated_registers_.end()) {
      if (registerIsAvailable(**it)) {
        **it = no_reg;
        allocated_registers_.erase(it);
      } else {
        it++;
      }
    }
  }
 
  static RegisterAllocator WithAllocatableGeneralRegisters() {
    RegList list;
    const RegisterConfiguration* config(RegisterConfiguration::Default());
 
    for (int i = 0; i < config->num_allocatable_general_registers(); ++i) {
      int code = config->GetAllocatableGeneralCode(i);
      Register candidate = Register::from_code(code);
      list.set(candidate);
    }
    return RegisterAllocator(list);
  }
 
 private:
  std::vector<Register*> allocated_registers_;
  const RegList initial_;
  RegList available_;
};
 
#define DEFINE_REG(Name)  \
  Register Name = no_reg; \
  regs.Ask(&Name);
 
#define ASSIGN_REG(Name) regs.Ask(&Name);
 
#define DEFINE_PINNED(Name, Reg) \
  Register Name = no_reg;        \
  regs.Pinned(Reg, &Name);
 
#define ASSIGN_PINNED(Name, Reg) regs.Pinned(Reg, &Name);
 
#define DEFINE_SCOPED(Name) \
  DEFINE_REG(Name)          \
  RegisterAllocator::Scoped scope_##Name(&regs, &Name);
 
#define FREE_REG(Name) regs.Free(&Name);
 
void ResetStackSwitchFrameStackSlots(MacroAssembler* masm) {
  ASM_CODE_COMMENT(masm);
  __ StoreWord(zero_reg,
               MemOperand(fp, StackSwitchFrameConstants::kResultArrayOffset));
  __ StoreWord(zero_reg,
               MemOperand(fp, StackSwitchFrameConstants::kImplicitArgOffset));
}
 
void LoadTargetJumpBuffer(MacroAssembler* masm, Register target_continuation,
                          Register tmp,
                          wasm::JumpBuffer::StackState expected_state) {
  ASM_CODE_COMMENT(masm);
  Register target_jmpbuf = target_continuation;
  __ LoadExternalPointerField(
      target_jmpbuf,
      FieldMemOperand(target_continuation,
                      WasmContinuationObject::kStackOffset),
      kWasmStackMemoryTag);
  __ AddWord(target_jmpbuf, target_jmpbuf, wasm::StackMemory::jmpbuf_offset());
  __ StoreWord(
      zero_reg,
      MemOperand(fp, StackSwitchFrameConstants::kGCScanSlotCountOffset));
  // Switch stack!
  LoadJumpBuffer(masm, target_jmpbuf, false, tmp, expected_state);
}
}  // namespace
 
void Builtins::Generate_WasmSuspend(MacroAssembler* masm) {
  auto regs = RegisterAllocator::WithAllocatableGeneralRegisters();
  // Set up the stackframe.
  __ EnterFrame(StackFrame::STACK_SWITCH);
 
  DEFINE_PINNED(suspender, a0);
  DEFINE_PINNED(context, kContextRegister);
 
  __ SubWord(
      sp, sp,
      Operand(StackSwitchFrameConstants::kNumSpillSlots * kSystemPointerSize));
  // Set a sentinel value for the spill slots visited by the GC.
  ResetStackSwitchFrameStackSlots(masm);
 
  // -------------------------------------------
  // Save current state in active jump buffer.
  // -------------------------------------------
  Label resume;
  DEFINE_REG(continuation);
  __ LoadRoot(continuation, RootIndex::kActiveContinuation);
  DEFINE_REG(jmpbuf);
  DEFINE_REG(scratch);
  __ LoadExternalPointerField(
      jmpbuf,
      FieldMemOperand(continuation, WasmContinuationObject::kStackOffset),
      kWasmStackMemoryTag);
  __ AddWord(jmpbuf, jmpbuf, wasm::StackMemory::jmpbuf_offset());
  FillJumpBuffer(masm, jmpbuf, &resume, scratch);
  SwitchStackState(masm, jmpbuf, scratch, wasm::JumpBuffer::Active,
                   wasm::JumpBuffer::Suspended);
  regs.ResetExcept(suspender, continuation);
 
  DEFINE_REG(suspender_continuation);
  __ LoadTaggedField(
      suspender_continuation,
      FieldMemOperand(suspender, WasmSuspenderObject::kContinuationOffset));
  if (v8_flags.debug_code) {
    // -------------------------------------------
    // Check that the suspender's continuation is the active continuation.
    // -------------------------------------------
    // TODO(thibaudm): Once we add core stack-switching instructions, this
    // check will not hold anymore: it's possible that the active continuation
    // changed (due to an internal switch), so we have to update the suspender.
    Label ok;
    __ Branch(&ok, eq, suspender_continuation, Operand(continuation));
    __ Trap();
    __ bind(&ok);
  }
  // -------------------------------------------
  // Update roots.
  // -------------------------------------------
  DEFINE_REG(caller);
  __ LoadTaggedField(caller,
                     FieldMemOperand(suspender_continuation,
                                     WasmContinuationObject::kParentOffset));
  int32_t active_continuation_offset =
      MacroAssembler::RootRegisterOffsetForRootIndex(
          RootIndex::kActiveContinuation);
  __ StoreWord(caller, MemOperand(kRootRegister, active_continuation_offset));
  DEFINE_REG(parent);
  __ LoadTaggedField(
      parent, FieldMemOperand(suspender, WasmSuspenderObject::kParentOffset));
  int32_t active_suspender_offset =
      MacroAssembler::RootRegisterOffsetForRootIndex(
          RootIndex::kActiveSuspender);
  __ StoreWord(parent, MemOperand(kRootRegister, active_suspender_offset));
  regs.ResetExcept(suspender, caller, continuation);
  // -------------------------------------------
  // Load jump buffer.
  // -------------------------------------------
  SwitchStacks(masm, continuation, false, caller, {caller, suspender});
  FREE_REG(continuation);
  ASSIGN_REG(jmpbuf);
  __ LoadExternalPointerField(
      jmpbuf, FieldMemOperand(caller, WasmContinuationObject::kStackOffset),
      kWasmStackMemoryTag);
  __ AddWord(jmpbuf, jmpbuf, wasm::StackMemory::jmpbuf_offset());
  __ LoadTaggedField(
      kReturnRegister0,
      FieldMemOperand(suspender, WasmSuspenderObject::kPromiseOffset));
  MemOperand GCScanSlotPlace =
      MemOperand(fp, StackSwitchFrameConstants::kGCScanSlotCountOffset);
  __ StoreWord(zero_reg, GCScanSlotPlace);
  ASSIGN_REG(scratch)
  LoadJumpBuffer(masm, jmpbuf, true, scratch, wasm::JumpBuffer::Inactive);
  __ Trap();
  __ bind(&resume);
  __ LeaveFrame(StackFrame::STACK_SWITCH);
  __ Ret();
}
 
 
namespace {
// Resume the suspender stored in the closure. We generate two variants of this
// builtin: the onFulfilled variant resumes execution at the saved PC and
// forwards the value, the onRejected variant throws the value.
 
void Generate_WasmResumeHelper(MacroAssembler* masm, wasm::OnResume on_resume) {
  auto regs = RegisterAllocator::WithAllocatableGeneralRegisters();
  UseScratchRegisterScope temps(masm);
  __ EnterFrame(StackFrame::STACK_SWITCH);
 
  DEFINE_PINNED(closure, kJSFunctionRegister);  // a1
 
  __ SubWord(
      sp, sp,
      Operand(StackSwitchFrameConstants::kNumSpillSlots * kSystemPointerSize));
  // Set a sentinel value for the spill slots visited by the GC.
  ResetStackSwitchFrameStackSlots(masm);
 
  regs.ResetExcept(closure);
 
  // -------------------------------------------
  // Load suspender from closure.
  // -------------------------------------------
  DEFINE_REG(sfi);
  __ LoadTaggedField(
      sfi,
      MemOperand(
          closure,
          wasm::ObjectAccess::SharedFunctionInfoOffsetInTaggedJSFunction()));
  FREE_REG(closure);
  // Suspender should be ObjectRegister register to be used in
  // RecordWriteField calls later.
  DEFINE_PINNED(suspender, WriteBarrierDescriptor::ObjectRegister());
  DEFINE_REG(resume_data);
  __ LoadTaggedField(
      resume_data,
      FieldMemOperand(sfi, SharedFunctionInfo::kUntrustedFunctionDataOffset));
  __ LoadTaggedField(
      suspender,
      FieldMemOperand(resume_data, WasmResumeData::kSuspenderOffset));
  regs.ResetExcept(suspender);
 
  // -------------------------------------------
  // Save current state.
  // -------------------------------------------
  Label suspend;
  DEFINE_REG(active_continuation);
  __ LoadRoot(active_continuation, RootIndex::kActiveContinuation);
  DEFINE_REG(current_jmpbuf);
  DEFINE_REG(scratch);
  __ LoadExternalPointerField(
      current_jmpbuf,
      FieldMemOperand(active_continuation,
                      WasmContinuationObject::kStackOffset),
      kWasmStackMemoryTag);
  __ AddWord(current_jmpbuf, current_jmpbuf,
             wasm::StackMemory::jmpbuf_offset());
  FillJumpBuffer(masm, current_jmpbuf, &suspend, scratch);
  SwitchStackState(masm, current_jmpbuf, scratch, wasm::JumpBuffer::Active,
                   wasm::JumpBuffer::Inactive);
  FREE_REG(current_jmpbuf);
  // -------------------------------------------
  // Set the suspender and continuation parents and update the roots
  // -------------------------------------------
  DEFINE_REG(active_suspender);
  __ LoadRoot(active_suspender, RootIndex::kActiveSuspender);
  __ StoreTaggedField(
      active_suspender,
      FieldMemOperand(suspender, WasmSuspenderObject::kParentOffset));
  __ RecordWriteField(suspender, WasmSuspenderObject::kParentOffset,
                      active_suspender, kRAHasBeenSaved,
                      SaveFPRegsMode::kIgnore);
  int32_t active_suspender_offset =
      MacroAssembler::RootRegisterOffsetForRootIndex(
          RootIndex::kActiveSuspender);
  __ StoreWord(suspender, MemOperand(kRootRegister, active_suspender_offset));
 
  // Next line we are going to load a field from suspender, but we have to use
  // the same register for target_continuation to use it in RecordWriteField.
  // So, free suspender here to use pinned reg, but load from it next line.
  FREE_REG(suspender);
  DEFINE_PINNED(target_continuation, WriteBarrierDescriptor::ObjectRegister());
  suspender = target_continuation;
  __ LoadTaggedField(
      target_continuation,
      FieldMemOperand(suspender, WasmSuspenderObject::kContinuationOffset));
  suspender = no_reg;
 
  __ StoreTaggedField(active_continuation,
                      FieldMemOperand(target_continuation,
                                      WasmContinuationObject::kParentOffset));
  DEFINE_PINNED(old_continuation, s10);
  __ mv(old_continuation, active_continuation);
  __ RecordWriteField(
      target_continuation, WasmContinuationObject::kParentOffset,
      active_continuation, kRAHasBeenSaved, SaveFPRegsMode::kIgnore);
  int32_t active_continuation_offset =
      MacroAssembler::RootRegisterOffsetForRootIndex(
          RootIndex::kActiveContinuation);
  __ StoreWord(target_continuation,
               MemOperand(kRootRegister, active_continuation_offset));
 
  SwitchStacks(masm, old_continuation, false, scratch, {target_continuation});
  regs.ResetExcept(target_continuation);
 
  // -------------------------------------------
  // Load state from target jmpbuf (longjmp).
  // -------------------------------------------
  regs.Reserve(kReturnRegister0);
  DEFINE_REG(target_jmpbuf);
  ASSIGN_REG(scratch);
 
  __ LoadExternalPointerField(
      target_jmpbuf,
      FieldMemOperand(target_continuation,
                      WasmContinuationObject::kStackOffset),
      kWasmStackMemoryTag);
  __ AddWord(target_jmpbuf, target_jmpbuf, wasm::StackMemory::jmpbuf_offset());
 
  // Move resolved value to return register.
  __ LoadWord(kReturnRegister0, MemOperand(fp, 3 * kSystemPointerSize));
  MemOperand GCScanSlotPlace =
      MemOperand(fp, StackSwitchFrameConstants::kGCScanSlotCountOffset);
  __ StoreWord(zero_reg, GCScanSlotPlace);
  if (on_resume == wasm::OnResume::kThrow) {
    // Switch to the continuation's stack without restoring the PC.
    LoadJumpBuffer(masm, target_jmpbuf, false, scratch,
                   wasm::JumpBuffer::Suspended);
    // Pop this frame now. The unwinder expects that the first STACK_SWITCH
    // frame is the outermost one.
    __ LeaveFrame(StackFrame::STACK_SWITCH);
    // Forward the onRejected value to kThrow.
    __ Push(kReturnRegister0);
    __ CallRuntime(Runtime::kThrow);
  } else {
    // Resume the continuation normally.
    LoadJumpBuffer(masm, target_jmpbuf, true, scratch,
                   wasm::JumpBuffer::Suspended);
  }
  __ Trap();
  __ bind(&suspend);
  __ LeaveFrame(StackFrame::STACK_SWITCH);
  // Pop receiver + parameter.
  // __ DropArguments(2);
  __ AddWord(sp, sp, Operand(2 * kSystemPointerSize));
  __ Ret();
}
}  // namespace
 
void Builtins::Generate_WasmResume(MacroAssembler* masm) {
  Generate_WasmResumeHelper(masm, wasm::OnResume::kContinue);
}
 
void Builtins::Generate_WasmReject(MacroAssembler* masm) {
  Generate_WasmResumeHelper(masm, wasm::OnResume::kThrow);
}
 
void Builtins::Generate_WasmOnStackReplace(MacroAssembler* masm) {
  // Only needed on x64.
  __ Trap();
}
 
namespace {
 
void SaveState(MacroAssembler* masm, Register active_continuation, Register tmp,
               Label* suspend) {
  ASM_CODE_COMMENT(masm);
  Register jmpbuf = tmp;
  __ LoadExternalPointerField(
      jmpbuf,
      FieldMemOperand(active_continuation,
                      WasmContinuationObject::kStackOffset),
      kWasmStackMemoryTag);
  __ AddWord(jmpbuf, jmpbuf, wasm::StackMemory::jmpbuf_offset());
  UseScratchRegisterScope temps(masm);
  Register scratch = temps.Acquire();
  FillJumpBuffer(masm, jmpbuf, suspend, scratch);
}
 
void SwitchToAllocatedStack(MacroAssembler* masm, RegisterAllocator& regs,
                            Register wasm_instance, Register wrapper_buffer,
                            Register& original_fp, Register& new_wrapper_buffer,
                            Label* suspend) {
  ASM_CODE_COMMENT(masm);
  UseScratchRegisterScope temps(masm);
  ResetStackSwitchFrameStackSlots(masm);
  DEFINE_SCOPED(scratch)
  DEFINE_REG(target_continuation)
  __ LoadRoot(target_continuation, RootIndex::kActiveContinuation);
  DEFINE_PINNED(parent_continuation, a2)
  __ LoadTaggedField(parent_continuation,
                     FieldMemOperand(target_continuation,
                                     WasmContinuationObject::kParentOffset));
  SaveState(masm, parent_continuation, scratch, suspend);
  SwitchStacks(masm, parent_continuation, false, scratch,
               {wasm_instance, wrapper_buffer});
  FREE_REG(parent_continuation);
  // Save the old stack's fp in t4, and use it to access the parameters in
  // the parent frame.
  regs.Pinned(t4, &original_fp);
  __ mv(original_fp, fp);
  __ LoadRoot(target_continuation, RootIndex::kActiveContinuation);
  LoadTargetJumpBuffer(masm, target_continuation, scratch,
                       wasm::JumpBuffer::Suspended);
  FREE_REG(target_continuation);
 
  // Push the loaded fp. We know it is null, because there is no frame yet,
  // so we could also push 0 directly. In any case we need to push it,
  // because this marks the base of the stack segment for
  // the stack frame iterator.
  __ EnterFrame(StackFrame::STACK_SWITCH);
 
  int stack_space =
      RoundUp(StackSwitchFrameConstants::kNumSpillSlots * kSystemPointerSize +
                  JSToWasmWrapperFrameConstants::kWrapperBufferSize,
              16);
  __ SubWord(sp, sp, Operand(stack_space));
 
  ASSIGN_REG(new_wrapper_buffer)
 
  __ mv(new_wrapper_buffer, sp);
  // Copy data needed for return handling from old wrapper buffer to new one.
  // kWrapperBufferRefReturnCount will be copied too, because 8 bytes are copied
  // at the same time.
  static_assert(JSToWasmWrapperFrameConstants::kWrapperBufferRefReturnCount ==
                JSToWasmWrapperFrameConstants::kWrapperBufferReturnCount + 4);
  __ LoadWord(
      scratch,
      MemOperand(wrapper_buffer,
                 JSToWasmWrapperFrameConstants::kWrapperBufferReturnCount));
  __ StoreWord(
      scratch,
      MemOperand(new_wrapper_buffer,
                 JSToWasmWrapperFrameConstants::kWrapperBufferReturnCount));
  __ LoadWord(
      scratch,
      MemOperand(
          wrapper_buffer,
          JSToWasmWrapperFrameConstants::kWrapperBufferSigRepresentationArray));
  __ StoreWord(
      scratch,
      MemOperand(
          new_wrapper_buffer,
          JSToWasmWrapperFrameConstants::kWrapperBufferSigRepresentationArray));
}
 
// Loads the context field of the WasmTrustedInstanceData or WasmImportData
// depending on the data's type, and places the result in the input register.
void GetContextFromImplicitArg(MacroAssembler* masm, Register data,
                               Register scratch) {
  __ LoadTaggedField(scratch, FieldMemOperand(data, HeapObject::kMapOffset));
  Label instance;
  Label end;
  __ GetInstanceTypeRange(scratch, scratch, WASM_TRUSTED_INSTANCE_DATA_TYPE,
                          scratch);
  // __ CompareInstanceType(scratch, scratch, WASM_TRUSTED_INSTANCE_DATA_TYPE);
  __ Branch(&instance, eq, scratch, Operand(zero_reg));
  __ LoadTaggedField(
      data, FieldMemOperand(data, WasmImportData::kNativeContextOffset));
  __ Branch(&end);
  __ bind(&instance);
  __ LoadTaggedField(
      data,
      FieldMemOperand(data, WasmTrustedInstanceData::kNativeContextOffset));
  __ bind(&end);
}
 
void SwitchBackAndReturnPromise(MacroAssembler* masm, RegisterAllocator& regs,
                                wasm::Promise mode, Label* return_promise) {
  ASM_CODE_COMMENT(masm);
  regs.ResetExcept();
  UseScratchRegisterScope temps(masm);
  // The return value of the wasm function becomes the parameter of the
  // FulfillPromise builtin, and the promise is the return value of this
  // wrapper.
  static const Builtin_FulfillPromise_InterfaceDescriptor desc;
  DEFINE_PINNED(promise, desc.GetRegisterParameter(0));
  DEFINE_PINNED(return_value, desc.GetRegisterParameter(1));
  DEFINE_SCOPED(tmp);
  DEFINE_SCOPED(tmp2);
  DEFINE_SCOPED(tmp3);
  if (mode == wasm::kPromise) {
    __ Move(return_value, kReturnRegister0);
    __ LoadRoot(promise, RootIndex::kActiveSuspender);
    __ LoadTaggedField(
        promise, FieldMemOperand(promise, WasmSuspenderObject::kPromiseOffset));
  }
  __ LoadWord(kContextRegister,
              MemOperand(fp, StackSwitchFrameConstants::kImplicitArgOffset));
  GetContextFromImplicitArg(masm, kContextRegister, tmp);
 
  ReloadParentContinuation(masm, promise, return_value, kContextRegister, tmp,
                           tmp2, tmp3);
  RestoreParentSuspender(masm, tmp, tmp2);
 
  if (mode == wasm::kPromise) {
    __ li(tmp, 1);
    __ StoreWord(
        tmp, MemOperand(fp, StackSwitchFrameConstants::kGCScanSlotCountOffset));
    __ Push(promise);
    __ CallBuiltin(Builtin::kFulfillPromise);
    __ Pop(promise);
  }
  FREE_REG(promise);
  FREE_REG(return_value);
  __ bind(return_promise);
}
 
void GenerateExceptionHandlingLandingPad(MacroAssembler* masm,
                                         RegisterAllocator& regs,
                                         Label* return_promise) {
  ASM_CODE_COMMENT(masm);
  static const Builtin_RejectPromise_InterfaceDescriptor desc;
  DEFINE_PINNED(promise, desc.GetRegisterParameter(0));
  DEFINE_PINNED(reason, desc.GetRegisterParameter(1));
  DEFINE_PINNED(debug_event, desc.GetRegisterParameter(2));
  int catch_handler = __ pc_offset();
  {
    DEFINE_SCOPED(thread_in_wasm_flag_addr);
    // Unset thread_in_wasm_flag.
    __ LoadWord(thread_in_wasm_flag_addr,
                MemOperand(kRootRegister,
                           Isolate::thread_in_wasm_flag_address_offset()));
    __ StoreWord(zero_reg, MemOperand(thread_in_wasm_flag_addr, 0));
  }
  // The exception becomes the parameter of the RejectPromise builtin, and the
  // promise is the return value of this wrapper.
  __ mv(reason, kReturnRegister0);
  __ LoadRoot(promise, RootIndex::kActiveSuspender);
  __ LoadTaggedField(
      promise, FieldMemOperand(promise, WasmSuspenderObject::kPromiseOffset));
 
  __ LoadWord(kContextRegister,
              MemOperand(fp, StackSwitchFrameConstants::kImplicitArgOffset));
  DEFINE_SCOPED(tmp);
  DEFINE_SCOPED(tmp2);
  DEFINE_SCOPED(tmp3);
  GetContextFromImplicitArg(masm, kContextRegister, tmp);
  ReloadParentContinuation(masm, promise, reason, kContextRegister, tmp, tmp2,
                           tmp3);
  RestoreParentSuspender(masm, tmp, tmp2);
 
  __ li(tmp, 1);
  __ StoreWord(
      tmp, MemOperand(fp, StackSwitchFrameConstants::kGCScanSlotCountOffset));
  __ Push(promise);
  __ LoadRoot(debug_event, RootIndex::kTrueValue);
  __ CallBuiltin(Builtin::kRejectPromise);
  __ Pop(promise);
 
  // Run the rest of the wrapper normally (deconstruct the frame, ...).
  __ jmp(return_promise);
 
  masm->isolate()->builtins()->SetJSPIPromptHandlerOffset(catch_handler);
}
 
void JSToWasmWrapperHelper(MacroAssembler* masm, wasm::Promise mode) {
  bool stack_switch = mode == wasm::kPromise || mode == wasm::kStressSwitch;
  auto regs = RegisterAllocator::WithAllocatableGeneralRegisters();
 
  __ EnterFrame(stack_switch ? StackFrame::STACK_SWITCH
                             : StackFrame::JS_TO_WASM);
 
  __ SubWord(
      sp, sp,
      Operand(StackSwitchFrameConstants::kNumSpillSlots * kSystemPointerSize));
 
  // Load the implicit argument (instance data or import data) from the frame.
  DEFINE_PINNED(implicit_arg, kWasmImplicitArgRegister);
  __ LoadWord(
      implicit_arg,
      MemOperand(fp, JSToWasmWrapperFrameConstants::kImplicitArgOffset));
 
  DEFINE_PINNED(wrapper_buffer,
                WasmJSToWasmWrapperDescriptor::WrapperBufferRegister());
 
  Label suspend;
  Register original_fp = no_reg;
  Register new_wrapper_buffer = no_reg;
  if (stack_switch) {
    SwitchToAllocatedStack(masm, regs, implicit_arg, wrapper_buffer,
                           original_fp, new_wrapper_buffer, &suspend);
  } else {
    original_fp = fp;
    new_wrapper_buffer = wrapper_buffer;
  }
 
  regs.ResetExcept(original_fp, wrapper_buffer, implicit_arg,
                   new_wrapper_buffer);
 
  {
    __ StoreWord(
        new_wrapper_buffer,
        MemOperand(fp, JSToWasmWrapperFrameConstants::kWrapperBufferOffset));
    if (stack_switch) {
      __ StoreWord(
          implicit_arg,
          MemOperand(fp, StackSwitchFrameConstants::kImplicitArgOffset));
      UseScratchRegisterScope temps(masm);
      Register scratch = temps.Acquire();
      __ LoadWord(
          scratch,
          MemOperand(original_fp,
                     JSToWasmWrapperFrameConstants::kResultArrayParamOffset));
      __ StoreWord(
          scratch,
          MemOperand(fp, StackSwitchFrameConstants::kResultArrayOffset));
    }
  }
  {
    DEFINE_SCOPED(result_size);
    __ LoadWord(
        result_size,
        MemOperand(wrapper_buffer, JSToWasmWrapperFrameConstants::
                                       kWrapperBufferStackReturnBufferSize));
    __ SllWord(result_size, result_size, kSystemPointerSizeLog2);
    __ SubWord(sp, sp, Operand(result_size));
  }
 
  __ StoreWord(
      sp,
      MemOperand(
          new_wrapper_buffer,
          JSToWasmWrapperFrameConstants::kWrapperBufferStackReturnBufferStart));
  if (stack_switch) {
    FREE_REG(new_wrapper_buffer)
  }
  FREE_REG(implicit_arg)
  for (auto reg : wasm::kGpParamRegisters) {
    regs.Reserve(reg);
  }
 
  // The first GP parameter holds the trusted instance data or the import data.
  // This is handled specially.
  int stack_params_offset =
      (arraysize(wasm::kGpParamRegisters) - 1) * kSystemPointerSize +
      arraysize(wasm::kFpParamRegisters) * kDoubleSize;
 
  {
    DEFINE_SCOPED(params_start);
    __ LoadWord(
        params_start,
        MemOperand(wrapper_buffer,
                   JSToWasmWrapperFrameConstants::kWrapperBufferParamStart));
    {
      // Push stack parameters on the stack.
      DEFINE_SCOPED(params_end);
      __ LoadWord(
          params_end,
          MemOperand(wrapper_buffer,
                     JSToWasmWrapperFrameConstants::kWrapperBufferParamEnd));
      DEFINE_SCOPED(last_stack_param);
 
      __ AddWord(last_stack_param, params_start, Operand(stack_params_offset));
      Label loop_start;
      __ bind(&loop_start);
 
      Label finish_stack_params;
      __ Branch(&finish_stack_params, ge, last_stack_param,
                Operand(params_end));
 
      // Push parameter
      {
        DEFINE_SCOPED(scratch);
        __ SubWord(params_end, params_end, Operand(kSystemPointerSize));
        __ LoadWord(scratch, MemOperand(params_end, 0));
        __ Push(scratch);
      }
      __ Branch(&loop_start);
 
      __ bind(&finish_stack_params);
    }
    int32_t next_offset = 0;
    for (size_t i = 1; i < arraysize(wasm::kGpParamRegisters); ++i) {
      // Check that {params_start} does not overlap with any of the parameter
      // registers, so that we don't overwrite it by accident with the loads
      // below.
      DCHECK_NE(params_start, wasm::kGpParamRegisters[i]);
      __ LoadWord(wasm::kGpParamRegisters[i],
                  MemOperand(params_start, next_offset));
      next_offset += kSystemPointerSize;
    }
 
    for (size_t i = 0; i < arraysize(wasm::kFpParamRegisters); ++i) {
      __ LoadDouble(wasm::kFpParamRegisters[i],
                    MemOperand(params_start, next_offset));
      next_offset += kDoubleSize;
    }
    DCHECK_EQ(next_offset, stack_params_offset);
  }
 
  {
    DEFINE_SCOPED(thread_in_wasm_flag_addr);
    __ LoadWord(thread_in_wasm_flag_addr,
                MemOperand(kRootRegister,
                           Isolate::thread_in_wasm_flag_address_offset()));
    DEFINE_SCOPED(scratch);
    __ li(scratch, 1);
    __ Sw(scratch, MemOperand(thread_in_wasm_flag_addr, 0));
  }
  __ StoreWord(
      zero_reg,
      MemOperand(fp, StackSwitchFrameConstants::kGCScanSlotCountOffset));
  {
    DEFINE_SCOPED(call_target);
    __ LoadWasmCodePointer(
        call_target,
        MemOperand(wrapper_buffer,
                   JSToWasmWrapperFrameConstants::kWrapperBufferCallTarget));
    // We do the call without a signature check here, since the wrapper loaded
    // the signature from the same trusted object as the call target to set up
    // the stack layout. We could add a signature hash and pass it through to
    // verify it here, but an attacker that could corrupt the signature could
    // also corrupt that signature hash (which is outside of the sandbox).
    __ CallWasmCodePointerNoSignatureCheck(call_target);
  }
 
  regs.ResetExcept();
  // The wrapper_buffer has to be in a2 as the correct parameter register.
  regs.Reserve(kReturnRegister0, kReturnRegister1);
  ASSIGN_PINNED(wrapper_buffer, a2);
  {
    DEFINE_SCOPED(thread_in_wasm_flag_addr);
    __ LoadWord(thread_in_wasm_flag_addr,
                MemOperand(kRootRegister,
                           Isolate::thread_in_wasm_flag_address_offset()));
    __ Sw(zero_reg, MemOperand(thread_in_wasm_flag_addr, 0));
  }
 
  __ LoadWord(
      wrapper_buffer,
      MemOperand(fp, JSToWasmWrapperFrameConstants::kWrapperBufferOffset));
 
  __ StoreDouble(
      wasm::kFpReturnRegisters[0],
      MemOperand(
          wrapper_buffer,
          JSToWasmWrapperFrameConstants::kWrapperBufferFPReturnRegister1));
  __ StoreDouble(
      wasm::kFpReturnRegisters[1],
      MemOperand(
          wrapper_buffer,
          JSToWasmWrapperFrameConstants::kWrapperBufferFPReturnRegister2));
  __ StoreWord(
      wasm::kGpReturnRegisters[0],
      MemOperand(
          wrapper_buffer,
          JSToWasmWrapperFrameConstants::kWrapperBufferGPReturnRegister1));
  __ StoreWord(
      wasm::kGpReturnRegisters[1],
      MemOperand(
          wrapper_buffer,
          JSToWasmWrapperFrameConstants::kWrapperBufferGPReturnRegister2));
  // Call the return value builtin with
  // a0: wasm instance.
  // a1: the result JSArray for multi-return.
  // a2: pointer to the byte buffer which contains all parameters.
  if (stack_switch) {
    __ LoadWord(a1,
                MemOperand(fp, StackSwitchFrameConstants::kResultArrayOffset));
    __ LoadWord(a0,
                MemOperand(fp, StackSwitchFrameConstants::kImplicitArgOffset));
  } else {
    __ LoadWord(
        a1,
        MemOperand(fp, JSToWasmWrapperFrameConstants::kResultArrayParamOffset));
    __ LoadWord(
        a0, MemOperand(fp, JSToWasmWrapperFrameConstants::kImplicitArgOffset));
  }
  {
    UseScratchRegisterScope temps(masm);
    GetContextFromImplicitArg(masm, a0, temps.Acquire());
  }
  __ CallBuiltin(Builtin::kJSToWasmHandleReturns);
 
  Label return_promise;
  if (stack_switch) {
    SwitchBackAndReturnPromise(masm, regs, mode, &return_promise);
  }
  __ bind(&suspend);
 
  __ LeaveFrame(stack_switch ? StackFrame::STACK_SWITCH
                             : StackFrame::JS_TO_WASM);
  // Despite returning to the different location for regular and stack switching
  // versions, incoming argument count matches both cases:
  // instance and result array without suspend or
  // or promise resolve/reject params for callback.
  constexpr int64_t stack_arguments_in = 2;
  // __ DropArguments(stack_arguments_in);
  __ AddWord(sp, sp, Operand(stack_arguments_in * kSystemPointerSize));
  __ Ret();
 
  // Catch handler for the stack-switching wrapper: reject the promise with the
  // thrown exception.
  if (mode == wasm::kPromise) {
    GenerateExceptionHandlingLandingPad(masm, regs, &return_promise);
  }
}
}  // namespace
 
void Builtins::Generate_JSToWasmWrapperAsm(MacroAssembler* masm) {
  UseScratchRegisterScope temps(masm);
  DCHECK(!AreAliased(WasmJSToWasmWrapperDescriptor::WrapperBufferRegister(),
                     kWasmImplicitArgRegister, t1, t2));
  JSToWasmWrapperHelper(masm, wasm::kNoPromise);
}
void Builtins::Generate_WasmReturnPromiseOnSuspendAsm(MacroAssembler* masm) {
  UseScratchRegisterScope temps(masm);
  DCHECK(!AreAliased(WasmJSToWasmWrapperDescriptor::WrapperBufferRegister(),
                     kWasmImplicitArgRegister, t1, t2));
  JSToWasmWrapperHelper(masm, wasm::kPromise);
}
void Builtins::Generate_JSToWasmStressSwitchStacksAsm(MacroAssembler* masm) {
  UseScratchRegisterScope temps(masm);
  DCHECK(!AreAliased(WasmJSToWasmWrapperDescriptor::WrapperBufferRegister(),
                     kWasmImplicitArgRegister, t1, t2));
  JSToWasmWrapperHelper(masm, wasm::kStressSwitch);
}
 
void Builtins::Generate_CallApiCallbackImpl(MacroAssembler* masm,
                                            CallApiCallbackMode mode) {
  // ----------- S t a t e -------------
  // CallApiCallbackMode::kOptimizedNoProfiling/kOptimized modes:
  //  -- a1                  : api function address
  // Both modes:
  //  -- a2                  : arguments count
  //  -- a3                  : FunctionTemplateInfo
  //  -- cp                  : context
  //  -- sp[0]               : receiver
  //  -- sp[8]               : first argument
  //  -- ...
  //  -- sp[(argc) * 8]      : last argument
  // -----------------------------------
  Register function_callback_info_arg = kCArgRegs[0];
 
  Register api_function_address = no_reg;
  Register argc = no_reg;
  Register func_templ = no_reg;
  Register topmost_script_having_context = no_reg;
  Register scratch = t0;
 
  switch (mode) {
    case CallApiCallbackMode::kGeneric:
      topmost_script_having_context = CallApiCallbackGenericDescriptor::
          TopmostScriptHavingContextRegister();
      argc = CallApiCallbackGenericDescriptor::ActualArgumentsCountRegister();
      func_templ =
          CallApiCallbackGenericDescriptor::FunctionTemplateInfoRegister();
      break;
 
    case CallApiCallbackMode::kOptimizedNoProfiling:
    case CallApiCallbackMode::kOptimized:
      // Caller context is always equal to current context because we don't
      // inline Api calls cross-context.
      topmost_script_having_context = kContextRegister;
      api_function_address =
          CallApiCallbackOptimizedDescriptor::ApiFunctionAddressRegister();
      argc = CallApiCallbackOptimizedDescriptor::ActualArgumentsCountRegister();
      func_templ =
          CallApiCallbackOptimizedDescriptor::FunctionTemplateInfoRegister();
      break;
  }
  DCHECK(!AreAliased(api_function_address, topmost_script_having_context, argc,
                     func_templ, scratch));
 
  using FCA = FunctionCallbackArguments;
  using ER = ExternalReference;
  using FC = ApiCallbackExitFrameConstants;
 
  static_assert(FCA::kArgsLength == 6);
  static_assert(FCA::kNewTargetIndex == 5);
  static_assert(FCA::kTargetIndex == 4);
  static_assert(FCA::kReturnValueIndex == 3);
  static_assert(FCA::kContextIndex == 2);
  static_assert(FCA::kIsolateIndex == 1);
  static_assert(FCA::kUnusedIndex == 0);
 
  // Set up FunctionCallbackInfo's implicit_args on the stack as follows:
  // Target state:
  //   sp[0 * kSystemPointerSize]: kUnused   <= FCA::implicit_args_
  //   sp[1 * kSystemPointerSize]: kIsolate
  //   sp[2 * kSystemPointerSize]: kContext
  //   sp[3 * kSystemPointerSize]: undefined (kReturnValue)
  //   sp[4 * kSystemPointerSize]: kTarget
  //   sp[5 * kSystemPointerSize]: undefined (kNewTarget)
  // Existing state:
  //   sp[6 * kSystemPointerSize]:            <= FCA:::values_
 
  __ StoreRootRelative(IsolateData::topmost_script_having_context_offset(),
                       topmost_script_having_context);
  if (mode == CallApiCallbackMode::kGeneric) {
    api_function_address = ReassignRegister(topmost_script_having_context);
  }
  // Reserve space on the stack.
  static constexpr int kStackSize = FCA::kArgsLength;
  static_assert(kStackSize % 2 == 0);
  __ SubWord(sp, sp, Operand(kStackSize * kSystemPointerSize));
 
  // kIsolate.
  __ li(scratch, ER::isolate_address());
  __ StoreWord(scratch,
               MemOperand(sp, FCA::kIsolateIndex * kSystemPointerSize));
 
  // kContext
  __ StoreWord(cp, MemOperand(sp, FCA::kContextIndex * kSystemPointerSize));
 
  // kReturnValue
  __ LoadRoot(scratch, RootIndex::kUndefinedValue);
  __ StoreWord(scratch,
               MemOperand(sp, FCA::kReturnValueIndex * kSystemPointerSize));
 
  // kTarget.
  __ StoreWord(func_templ,
               MemOperand(sp, FCA::kTargetIndex * kSystemPointerSize));
 
  // kNewTarget.
  __ StoreWord(scratch,
               MemOperand(sp, FCA::kNewTargetIndex * kSystemPointerSize));
 
  // kUnused.
  __ StoreWord(scratch, MemOperand(sp, FCA::kUnusedIndex * kSystemPointerSize));
 
  FrameScope frame_scope(masm, StackFrame::MANUAL);
  if (mode == CallApiCallbackMode::kGeneric) {
    __ LoadExternalPointerField(
        api_function_address,
        FieldMemOperand(func_templ,
                        FunctionTemplateInfo::kMaybeRedirectedCallbackOffset),
        kFunctionTemplateInfoCallbackTag);
  }
 
  __ EnterExitFrame(scratch, FC::getExtraSlotsCountFrom<ExitFrameConstants>(),
                    StackFrame::API_CALLBACK_EXIT);
  MemOperand argc_operand = MemOperand(fp, FC::kFCIArgcOffset);
  {
    ASM_CODE_COMMENT_STRING(masm, "Initialize v8::FunctionCallbackInfo");
    // FunctionCallbackInfo::length_.
    // TODO(ishell): pass JSParameterCount(argc) to simplify things on the
    // caller end.
    __ StoreWord(argc, argc_operand);
    // FunctionCallbackInfo::implicit_args_.
    __ AddWord(scratch, fp, Operand(FC::kImplicitArgsArrayOffset));
    __ StoreWord(scratch, MemOperand(fp, FC::kFCIImplicitArgsOffset));
    // FunctionCallbackInfo::values_ (points at JS arguments on the stack).
    __ AddWord(scratch, fp, Operand(FC::kFirstArgumentOffset));
    __ StoreWord(scratch, MemOperand(fp, FC::kFCIValuesOffset));
  }
  __ RecordComment("v8::FunctionCallback's argument");
  __ AddWord(function_callback_info_arg, fp,
             Operand(FC::kFunctionCallbackInfoOffset));
  DCHECK(!AreAliased(api_function_address, function_callback_info_arg));
  ExternalReference thunk_ref = ER::invoke_function_callback(mode);
  Register no_thunk_arg = no_reg;
  MemOperand return_value_operand = MemOperand(fp, FC::kReturnValueOffset);
  static constexpr int kSlotsToDropOnReturn =
      FC::kFunctionCallbackInfoArgsLength + kJSArgcReceiverSlots;
  const bool with_profiling =
      mode != CallApiCallbackMode::kOptimizedNoProfiling;
  CallApiFunctionAndReturn(masm, with_profiling, api_function_address,
                           thunk_ref, no_thunk_arg, kSlotsToDropOnReturn,
                           &argc_operand, return_value_operand);
}
 
void Builtins::Generate_CallApiGetter(MacroAssembler* masm) {
  // ----------- S t a t e -------------
  //  -- cp                  : context
  //  -- a1                  : receiver
  //  -- a3                  : accessor info
  //  -- a0                  : holder
  // -----------------------------------
 
  Register name_arg = kCArgRegs[0];
  Register property_callback_info_arg = kCArgRegs[1];
 
  Register api_function_address = kCArgRegs[2];
 
  Register receiver = ApiGetterDescriptor::ReceiverRegister();
  Register holder = ApiGetterDescriptor::HolderRegister();
  Register callback = ApiGetterDescriptor::CallbackRegister();
  Register scratch = a4;
  DCHECK(!AreAliased(receiver, holder, callback, scratch));
 
  // Build v8::PropertyCallbackInfo::args_ array on the stack and push property
  // name below the exit frame to make GC aware of them.
  using PCA = PropertyCallbackArguments;
  using ER = ExternalReference;
  using FC = ApiAccessorExitFrameConstants;
  static_assert(PCA::kPropertyKeyIndex == 0);
  static_assert(PCA::kShouldThrowOnErrorIndex == 1);
  static_assert(PCA::kHolderIndex == 2);
  static_assert(PCA::kIsolateIndex == 3);
  static_assert(PCA::kHolderV2Index == 4);
  static_assert(PCA::kReturnValueIndex == 5);
  static_assert(PCA::kDataIndex == 6);
  static_assert(PCA::kThisIndex == 7);
  static_assert(PCA::kArgsLength == 8);
  // Set up v8::PropertyCallbackInfo's (PCI) args_ on the stack as follows:
  // Target state:
  //   sp[0 * kSystemPointerSize]: name                      <= PCI::args_
  //   sp[1 * kSystemPointerSize]: kShouldThrowOnErrorIndex
  //   sp[2 * kSystemPointerSize]: kHolderIndex
  //   sp[3 * kSystemPointerSize]: kIsolateIndex
  //   sp[4 * kSystemPointerSize]: kHolderV2Index
  //   sp[5 * kSystemPointerSize]: kReturnValueIndex
  //   sp[6 * kSystemPointerSize]: kDataIndex
  //   sp[7 * kSystemPointerSize]: kThisIndex / receiver
  __ SubWord(sp, sp, (PCA::kArgsLength)*kSystemPointerSize);
  __ StoreWord(receiver, MemOperand(sp, (PCA::kThisIndex)*kSystemPointerSize));
  __ LoadTaggedField(scratch,
                     FieldMemOperand(callback, AccessorInfo::kDataOffset));
  __ StoreWord(scratch, MemOperand(sp, (PCA::kDataIndex)*kSystemPointerSize));
  __ LoadRoot(scratch, RootIndex::kUndefinedValue);
  __ StoreWord(scratch,
               MemOperand(sp, (PCA::kReturnValueIndex)*kSystemPointerSize));
  __ StoreWord(zero_reg,
               MemOperand(sp, (PCA::kHolderV2Index)*kSystemPointerSize));
  __ li(scratch, ER::isolate_address());
  __ StoreWord(scratch,
               MemOperand(sp, (PCA::kIsolateIndex)*kSystemPointerSize));
  __ StoreWord(holder, MemOperand(sp, (PCA::kHolderIndex)*kSystemPointerSize));
  // should_throw_on_error -> false
  DCHECK_EQ(0, Smi::zero().ptr());
  __ StoreWord(
      zero_reg,
      MemOperand(sp, (PCA::kShouldThrowOnErrorIndex)*kSystemPointerSize));
  __ LoadTaggedField(scratch,
                     FieldMemOperand(callback, AccessorInfo::kNameOffset));
  __ StoreWord(scratch, MemOperand(sp, 0 * kSystemPointerSize));
 
  __ RecordComment("Load api_function_address");
  __ LoadExternalPointerField(
      api_function_address,
      FieldMemOperand(callback, AccessorInfo::kMaybeRedirectedGetterOffset),
      kAccessorInfoGetterTag);
 
  FrameScope frame_scope(masm, StackFrame::MANUAL);
  __ EnterExitFrame(scratch, FC::getExtraSlotsCountFrom<ExitFrameConstants>(),
                    StackFrame::API_ACCESSOR_EXIT);
  __ RecordComment("Create v8::PropertyCallbackInfo object on the stack.");
  // property_callback_info_arg = v8::PropertyCallbackInfo&
  __ AddWord(property_callback_info_arg, fp, Operand(FC::kArgsArrayOffset));
  DCHECK(!AreAliased(api_function_address, property_callback_info_arg, name_arg,
                     callback, scratch));
#ifdef V8_ENABLE_DIRECT_HANDLE
  // name_arg = Local<Name>(name), name value was pushed to GC-ed stack space.
  // |name_arg| is already initialized above.
#else
  // name_arg = Local<Name>(&name), which is &args_array[kPropertyKeyIndex].
  static_assert(PCA::kPropertyKeyIndex == 0);
  __ mv(name_arg, property_callback_info_arg);
#endif
 
  ExternalReference thunk_ref = ER::invoke_accessor_getter_callback();
  // Pass AccessorInfo to thunk wrapper in case profiler or side-effect
  // checking is enabled.
  Register thunk_arg = callback;
 
  MemOperand return_value_operand = MemOperand(fp, FC::kReturnValueOffset);
  static constexpr int kSlotsToDropOnReturn =
      FC::kPropertyCallbackInfoArgsLength;
  MemOperand* const kUseStackSpaceConstant = nullptr;
 
  const bool with_profiling = true;
  CallApiFunctionAndReturn(masm, with_profiling, api_function_address,
                           thunk_ref, thunk_arg, kSlotsToDropOnReturn,
                           kUseStackSpaceConstant, return_value_operand);
}
 
void Builtins::Generate_DirectCEntry(MacroAssembler* masm) {
  // The sole purpose of DirectCEntry is for movable callers (e.g. any general
  // purpose InstructionStream object) to be able to call into C functions that
  // may trigger GC and thus move the caller.
  //
  // DirectCEntry places the return address on the stack (updated by the GC),
  // making the call GC safe. The irregexp backend relies on this.
 
  // Make place for arguments to fit C calling convention. Callers use
  // EnterExitFrame/LeaveExitFrame so they handle stack restoring and we don't
  // have to do that here. Any caller must drop kCArgsSlotsSize stack space
  // after the call.
  __ AddWord(sp, sp, -kCArgsSlotsSize);
 
  __ StoreWord(ra,
               MemOperand(sp, kCArgsSlotsSize));  // Store the return address.
  __ Call(t6);                                    // Call the C++ function.
  __ LoadWord(t6, MemOperand(sp, kCArgsSlotsSize));  // Return to calling code.
 
  if (v8_flags.debug_code && v8_flags.enable_slow_asserts) {
    // In case of an error the return address may point to a memory area
    // filled with kZapValue by the GC. Dereference the address and check for
    // this.
    __ LoadWord(a4, MemOperand(t6));
    __ Assert(ne, AbortReason::kReceivedInvalidReturnAddress, a4,
              Operand(kZapValue));
  }
 
  __ Jump(t6);
}
 
namespace {
 
// This code tries to be close to ia32 code so that any changes can be
// easily ported.
void Generate_DeoptimizationEntry(MacroAssembler* masm,
                                  DeoptimizeKind deopt_kind) {
  Isolate* isolate = masm->isolate();
 
  // Unlike on ARM we don't save all the registers, just the useful ones.
  // For the rest, there are gaps on the stack, so the offsets remain the same.
  const int kNumberOfRegisters = Register::kNumRegisters;
 
  RegList restored_regs = kJSCallerSaved | kCalleeSaved;
  RegList saved_regs = restored_regs | sp | ra;
 
  const int kDoubleRegsSize = kDoubleSize * DoubleRegister::kNumRegisters;
 
  // Save all double FPU registers before messing with them.
  __ SubWord(sp, sp, Operand(kDoubleRegsSize));
  const RegisterConfiguration* config = RegisterConfiguration::Default();
  for (int i = 0; i < config->num_allocatable_double_registers(); ++i) {
    int code = config->GetAllocatableDoubleCode(i);
    const DoubleRegister fpu_reg = DoubleRegister::from_code(code);
    int offset = code * kDoubleSize;
    __ StoreDouble(fpu_reg, MemOperand(sp, offset));
  }
 
  // Push saved_regs (needed to populate FrameDescription::registers_).
  // Leave gaps for other registers.
  __ SubWord(sp, sp, kNumberOfRegisters * kSystemPointerSize);
  for (int16_t i = kNumberOfRegisters - 1; i >= 0; i--) {
    if ((saved_regs.bits() & (1 << i)) != 0) {
      __ StoreWord(ToRegister(i), MemOperand(sp, kSystemPointerSize * i));
    }
  }
 
  __ li(a2,
        ExternalReference::Create(IsolateAddressId::kCEntryFPAddress, isolate));
  __ StoreWord(fp, MemOperand(a2));
 
  const int kSavedRegistersAreaSize =
      (kNumberOfRegisters * kSystemPointerSize) + kDoubleRegsSize;
 
  // Get the address of the location in the code object (a2) (return
  // address for lazy deoptimization) and compute the fp-to-sp delta in
  // register a4.
  __ Move(a2, ra);
  __ AddWord(a3, sp, Operand(kSavedRegistersAreaSize));
 
  __ SubWord(a3, fp, a3);
 
  // Allocate a new deoptimizer object.
  __ PrepareCallCFunction(5, a4);
  // Pass five arguments, according to n64 ABI.
  __ Move(a0, zero_reg);
  Label context_check;
  __ LoadWord(a1,
              MemOperand(fp, CommonFrameConstants::kContextOrFrameTypeOffset));
  __ JumpIfSmi(a1, &context_check);
  __ LoadWord(a0, MemOperand(fp, StandardFrameConstants::kFunctionOffset));
  __ bind(&context_check);
  __ li(a1, Operand(static_cast<int64_t>(deopt_kind)));
  // a2: code object address
  // a3: fp-to-sp delta
  __ li(a4, ExternalReference::isolate_address());
 
  // Call Deoptimizer::New().
  {
    AllowExternalCallThatCantCauseGC scope(masm);
    __ CallCFunction(ExternalReference::new_deoptimizer_function(), 5);
  }
 
  // Preserve "deoptimizer" object in register a0 and get the input
  // frame descriptor pointer to a1 (deoptimizer->input_);
  __ LoadWord(a1, MemOperand(a0, Deoptimizer::input_offset()));
 
  // Copy core registers into FrameDescription::registers_[kNumRegisters].
  DCHECK_EQ(Register::kNumRegisters, kNumberOfRegisters);
  for (int i = 0; i < kNumberOfRegisters; i++) {
    int offset =
        (i * kSystemPointerSize) + FrameDescription::registers_offset();
    if ((saved_regs.bits() & (1 << i)) != 0) {
      __ LoadWord(a2, MemOperand(sp, i * kSystemPointerSize));
      __ StoreWord(a2, MemOperand(a1, offset));
    } else if (v8_flags.debug_code) {
      __ li(a2, kDebugZapValue);
      __ StoreWord(a2, MemOperand(a1, offset));
    }
  }
 
  int double_regs_offset = FrameDescription::double_registers_offset();
  // int simd128_regs_offset = FrameDescription::simd128_registers_offset();
  //  Copy FPU registers to
  //  double_registers_[DoubleRegister::kNumAllocatableRegisters]
  for (int i = 0; i < config->num_allocatable_double_registers(); ++i) {
    int code = config->GetAllocatableDoubleCode(i);
    int dst_offset = code * kDoubleSize + double_regs_offset;
    int src_offset =
        code * kDoubleSize + kNumberOfRegisters * kSystemPointerSize;
    __ LoadDouble(ft0, MemOperand(sp, src_offset));
    __ StoreDouble(ft0, MemOperand(a1, dst_offset));
  }
  // TODO(riscv): Add Simd128 copy
 
  // Remove the saved registers from the stack.
  __ AddWord(sp, sp, Operand(kSavedRegistersAreaSize));
 
  // Compute a pointer to the unwinding limit in register a2; that is
  // the first stack slot not part of the input frame.
  __ LoadWord(a2, MemOperand(a1, FrameDescription::frame_size_offset()));
  __ AddWord(a2, a2, sp);
 
  // Unwind the stack down to - but not including - the unwinding
  // limit and copy the contents of the activation frame to the input
  // frame description.
  __ AddWord(a3, a1, Operand(FrameDescription::frame_content_offset()));
  Label pop_loop;
  Label pop_loop_header;
  __ BranchShort(&pop_loop_header);
  __ bind(&pop_loop);
  __ pop(a4);
  __ StoreWord(a4, MemOperand(a3, 0));
  __ AddWord(a3, a3, kSystemPointerSize);
  __ bind(&pop_loop_header);
  __ Branch(&pop_loop, ne, a2, Operand(sp), Label::Distance::kNear);
  // Compute the output frame in the deoptimizer.
  __ push(a0);  // Preserve deoptimizer object across call.
  // a0: deoptimizer object; a1: scratch.
  __ PrepareCallCFunction(1, a1);
  // Call Deoptimizer::ComputeOutputFrames().
  {
    AllowExternalCallThatCantCauseGC scope(masm);
    __ CallCFunction(ExternalReference::compute_output_frames_function(), 1);
  }
  __ pop(a0);  // Restore deoptimizer object (class Deoptimizer).
 
  __ LoadWord(sp, MemOperand(a0, Deoptimizer::caller_frame_top_offset()));
 
  // Replace the current (input) frame with the output frames.
  Label outer_push_loop, inner_push_loop, outer_loop_header, inner_loop_header;
  // Outer loop state: a4 = current "FrameDescription** output_",
  // a1 = one past the last FrameDescription**.
  __ Lw(a1, MemOperand(a0, Deoptimizer::output_count_offset()));
  __ LoadWord(a4,
              MemOperand(a0, Deoptimizer::output_offset()));  // a4 is output_.
  __ CalcScaledAddress(a1, a4, a1, kSystemPointerSizeLog2);
  __ BranchShort(&outer_loop_header);
  __ bind(&outer_push_loop);
  // Inner loop state: a2 = current FrameDescription*, a3 = loop index.
  __ LoadWord(a2, MemOperand(a4, 0));  // output_[ix]
  __ LoadWord(a3, MemOperand(a2, FrameDescription::frame_size_offset()));
  __ BranchShort(&inner_loop_header);
  __ bind(&inner_push_loop);
  __ SubWord(a3, a3, Operand(kSystemPointerSize));
  __ AddWord(a6, a2, Operand(a3));
  __ LoadWord(a7, MemOperand(a6, FrameDescription::frame_content_offset()));
  __ push(a7);
  __ bind(&inner_loop_header);
  __ Branch(&inner_push_loop, ne, a3, Operand(zero_reg));
 
  __ AddWord(a4, a4, Operand(kSystemPointerSize));
  __ bind(&outer_loop_header);
  __ Branch(&outer_push_loop, lt, a4, Operand(a1));
 
  __ LoadWord(a1, MemOperand(a0, Deoptimizer::input_offset()));
  for (int i = 0; i < config->num_allocatable_double_registers(); ++i) {
    int code = config->GetAllocatableDoubleCode(i);
    const DoubleRegister fpu_reg = DoubleRegister::from_code(code);
    int src_offset = code * kDoubleSize + double_regs_offset;
    __ LoadDouble(fpu_reg, MemOperand(a1, src_offset));
  }
 
  // Push pc and continuation from the last output frame.
  __ LoadWord(a6, MemOperand(a2, FrameDescription::pc_offset()));
  __ push(a6);
  __ LoadWord(a6, MemOperand(a2, FrameDescription::continuation_offset()));
  __ push(a6);
 
  // Technically restoring 't3' should work unless zero_reg is also restored
  // but it's safer to check for this.
  DCHECK(!(restored_regs.has(t3)));
  // Restore the registers from the last output frame.
  __ Move(t3, a2);
  for (int i = kNumberOfRegisters - 1; i >= 0; i--) {
    int offset =
        (i * kSystemPointerSize) + FrameDescription::registers_offset();
    if ((restored_regs.bits() & (1 << i)) != 0) {
      __ LoadWord(ToRegister(i), MemOperand(t3, offset));
    }
  }
 
  __ pop(t6);  // Get continuation, leave pc on stack.
  __ pop(ra);
  Label end;
  __ Branch(&end, eq, t6, Operand(zero_reg));
  __ Jump(t6);
  __ bind(&end);
  __ Ret();
  __ stop();
}
 
}  // namespace
 
void Builtins::Generate_DeoptimizationEntry_Eager(MacroAssembler* masm) {
  Generate_DeoptimizationEntry(masm, DeoptimizeKind::kEager);
}
 
void Builtins::Generate_DeoptimizationEntry_Lazy(MacroAssembler* masm) {
  Generate_DeoptimizationEntry(masm, DeoptimizeKind::kLazy);
}
 
// If there is baseline code on the shared function info, converts an
// interpreter frame into a baseline frame and continues execution in baseline
// code. Otherwise execution continues with bytecode.
void Builtins::Generate_InterpreterOnStackReplacement_ToBaseline(
    MacroAssembler* masm) {
  Label start;
  __ bind(&start);
 
  // Get function from the frame.
  Register closure = a1;
  __ LoadWord(closure, MemOperand(fp, StandardFrameConstants::kFunctionOffset));
 
  // Get the InstructionStream object from the shared function info.
  Register code_obj = s1;
  __ LoadTaggedField(
      code_obj,
      FieldMemOperand(closure, JSFunction::kSharedFunctionInfoOffset));
 
  ResetSharedFunctionInfoAge(masm, code_obj);
 
  __ LoadTrustedPointerField(
      code_obj,
      FieldMemOperand(code_obj, SharedFunctionInfo::kTrustedFunctionDataOffset),
      kUnknownIndirectPointerTag);
 
  // For OSR entry it is safe to assume we always have baseline code.
  if (v8_flags.debug_code) {
    UseScratchRegisterScope temps(masm);
    Register scratch = temps.Acquire();
    __ GetObjectType(code_obj, scratch, scratch);
    __ Assert(eq, AbortReason::kExpectedBaselineData, scratch,
              Operand(CODE_TYPE));
    AssertCodeIsBaseline(masm, code_obj, scratch);
  }
 
  // Load the feedback cell and vector.
  Register feedback_cell = a2;
  Register feedback_vector = t4;
  __ LoadTaggedField(feedback_cell,
                     FieldMemOperand(closure, JSFunction::kFeedbackCellOffset));
  __ LoadTaggedField(
      feedback_vector,
      FieldMemOperand(feedback_cell, FeedbackCell::kValueOffset));
  Label install_baseline_code;
  // Check if feedback vector is valid. If not, call prepare for baseline to
  // allocate it.
  {
    UseScratchRegisterScope temps(masm);
    Register type = temps.Acquire();
    __ GetObjectType(feedback_vector, type, type);
    __ Branch(&install_baseline_code, ne, type, Operand(FEEDBACK_VECTOR_TYPE));
  }
  // Save BytecodeOffset from the stack frame.
  __ SmiUntag(kInterpreterBytecodeOffsetRegister,
              MemOperand(fp, InterpreterFrameConstants::kBytecodeOffsetFromFp));
  // Replace bytecode offset with feedback cell.
  static_assert(InterpreterFrameConstants::kBytecodeOffsetFromFp ==
                BaselineFrameConstants::kFeedbackCellFromFp);
  __ StoreWord(feedback_cell,
               MemOperand(fp, BaselineFrameConstants::kFeedbackCellFromFp));
  feedback_cell = no_reg;
  // Update feedback vector cache.
  static_assert(InterpreterFrameConstants::kFeedbackVectorFromFp ==
                BaselineFrameConstants::kFeedbackVectorFromFp);
  __ StoreWord(
      feedback_vector,
      MemOperand(fp, InterpreterFrameConstants::kFeedbackVectorFromFp));
  feedback_vector = no_reg;
 
  // Compute baseline pc for bytecode offset.
  Register get_baseline_pc = a3;
  __ li(get_baseline_pc,
        ExternalReference::baseline_pc_for_next_executed_bytecode());
 
  __ SubWord(kInterpreterBytecodeOffsetRegister,
             kInterpreterBytecodeOffsetRegister,
             (BytecodeArray::kHeaderSize - kHeapObjectTag));
 
  // Get bytecode array from the stack frame.
  __ LoadWord(kInterpreterBytecodeArrayRegister,
              MemOperand(fp, InterpreterFrameConstants::kBytecodeArrayFromFp));
  __ Push(kInterpreterAccumulatorRegister);
  {
    __ Move(kCArgRegs[0], code_obj);
    __ Move(kCArgRegs[1], kInterpreterBytecodeOffsetRegister);
    __ Move(kCArgRegs[2], kInterpreterBytecodeArrayRegister);
    FrameScope scope(masm, StackFrame::INTERNAL);
    __ PrepareCallCFunction(3, 0, a4);
    __ CallCFunction(get_baseline_pc, 3, 0);
  }
  __ LoadCodeInstructionStart(code_obj, code_obj, kJSEntrypointTag);
  __ AddWord(code_obj, code_obj, kReturnRegister0);
  __ Pop(kInterpreterAccumulatorRegister);
 
  // Reset the OSR loop nesting depth to disarm back edges.
  // TODO(pthier): Separate baseline Sparkplug from TF arming and don't disarm
  // Sparkplug here.
  __ LoadWord(kInterpreterBytecodeArrayRegister,
              MemOperand(fp, InterpreterFrameConstants::kBytecodeArrayFromFp));
  Generate_OSREntry(masm, code_obj);
  __ Trap();  // Unreachable.
 
  __ bind(&install_baseline_code);
  {
    FrameScope scope(masm, StackFrame::INTERNAL);
    __ Push(kInterpreterAccumulatorRegister);
    __ Push(closure);
    __ CallRuntime(Runtime::kInstallBaselineCode, 1);
    __ Pop(kInterpreterAccumulatorRegister);
  }
  // Retry from the start after installing baseline code.
  __ Branch(&start);
}
 
void Builtins::Generate_RestartFrameTrampoline(MacroAssembler* masm) {
  // Frame is being dropped:
  // - Look up current function on the frame.
  // - Leave the frame.
  // - Restart the frame by calling the function.
 
  __ LoadWord(a1, MemOperand(fp, StandardFrameConstants::kFunctionOffset));
  __ LoadWord(a0, MemOperand(fp, StandardFrameConstants::kArgCOffset));
 
  // Pop return address and frame.
  __ LeaveFrame(StackFrame::INTERPRETED);
 
#if defined(V8_ENABLE_LEAPTIERING) && defined(V8_TARGET_ARCH_RISCV64)
  __ InvokeFunction(a1, a0, InvokeType::kJump,
                    ArgumentAdaptionMode::kDontAdapt);
#else
  __ li(a2, Operand(kDontAdaptArgumentsSentinel));
  __ InvokeFunction(a1, a2, a0, InvokeType::kJump);
#endif
}
 
#undef __
 
}  // namespace internal
}  // namespace v8