builtins-arm.cc

Go to the documentation of this file.

// Copyright 2012 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
 
#if V8_TARGET_ARCH_ARM
 
#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"
// For interpreter_entry_return_pc_offset. TODO(jkummerow): Drop.
#include "src/codegen/macro-assembler-inl.h"
#include "src/codegen/register-configuration.h"
#include "src/debug/debug.h"
#include "src/deoptimizer/deoptimizer.h"
#include "src/execution/frame-constants.h"
#include "src/execution/frames.h"
#include "src/heap/heap-inl.h"
#include "src/logging/counters.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) {
#if defined(__thumb__)
  // Thumb mode builtin.
  DCHECK_EQ(1, reinterpret_cast<uintptr_t>(
                   ExternalReference::Create(address).address()) &
                   1);
#endif
  __ Move(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,
                            ArgumentsElementType element_type) {
  DCHECK(!AreAliased(array, argc, scratch));
  UseScratchRegisterScope temps(masm);
  Register counter = scratch;
  Register value = temps.Acquire();
  Label loop, entry;
  __ sub(counter, argc, Operand(kJSArgcReceiverSlots));
  __ b(&entry);
  __ bind(&loop);
  __ ldr(value, MemOperand(array, counter, LSL, kSystemPointerSizeLog2));
  if (element_type == ArgumentsElementType::kHandle) {
    __ ldr(value, MemOperand(value));
  }
  __ push(value);
  __ bind(&entry);
  __ sub(counter, counter, Operand(1), SetCC);
  __ b(ge, &loop);
}
 
void Generate_JSBuiltinsConstructStubHelper(MacroAssembler* masm) {
  // ----------- S t a t e -------------
  //  -- r0     : number of arguments
  //  -- r1     : constructor function
  //  -- r3     : new target
  //  -- cp     : context
  //  -- lr     : return address
  //  -- sp[...]: constructor arguments
  // -----------------------------------
 
  Register scratch = r2;
 
  Label stack_overflow;
 
  __ StackOverflowCheck(r0, scratch, &stack_overflow);
 
  // Enter a construct frame.
  {
    FrameAndConstantPoolScope scope(masm, StackFrame::CONSTRUCT);
 
    // Preserve the incoming parameters on the stack.
    __ Push(cp, r0);
 
    // 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.
 
    // Set up pointer to first argument (skip receiver).
    __ add(
        r4, fp,
        Operand(StandardFrameConstants::kCallerSPOffset + kSystemPointerSize));
    // Copy arguments and receiver to the expression stack.
    // r4: Pointer to start of arguments.
    // r0: Number of arguments.
    Generate_PushArguments(masm, r4, r0, r5, ArgumentsElementType::kRaw);
    // The receiver for the builtin/api call.
    __ PushRoot(RootIndex::kTheHoleValue);
 
    // Call the function.
    // r0: number of arguments (untagged)
    // r1: constructor function
    // r3: new target
    __ InvokeFunctionWithNewTarget(r1, r3, r0, InvokeType::kCall);
 
    // Restore context from the frame.
    __ ldr(cp, MemOperand(fp, ConstructFrameConstants::kContextOffset));
    // Restore arguments count from the frame.
    __ ldr(scratch, MemOperand(fp, ConstructFrameConstants::kLengthOffset));
    // Leave construct frame.
  }
 
  // Remove caller arguments from the stack and return.
  __ DropArguments(scratch);
  __ Jump(lr);
 
  __ bind(&stack_overflow);
  {
    FrameScope scope(masm, StackFrame::INTERNAL);
    __ CallRuntime(Runtime::kThrowStackOverflow);
    __ bkpt(0);  // Unreachable code.
  }
}
 
}  // namespace
 
// The construct stub for ES5 constructor functions and ES6 class constructors.
void Builtins::Generate_JSConstructStubGeneric(MacroAssembler* masm) {
  // ----------- S t a t e -------------
  //  --      r0: number of arguments (untagged)
  //  --      r1: constructor function
  //  --      r3: new target
  //  --      cp: context
  //  --      lr: return address
  //  -- sp[...]: constructor arguments
  // -----------------------------------
 
  FrameScope scope(masm, StackFrame::MANUAL);
  // Enter a construct frame.
  Label post_instantiation_deopt_entry, not_create_implicit_receiver;
  __ EnterFrame(StackFrame::CONSTRUCT);
 
  // Preserve the incoming parameters on the stack.
  __ LoadRoot(r4, RootIndex::kTheHoleValue);
  __ Push(cp, r0, r1, r4, r3);
 
  // ----------- S t a t e -------------
  //  --        sp[0*kPointerSize]: new target
  //  --        sp[1*kPointerSize]: padding
  //  -- r1 and sp[2*kPointerSize]: constructor function
  //  --        sp[3*kPointerSize]: number of arguments
  //  --        sp[4*kPointerSize]: context
  // -----------------------------------
 
  __ ldr(r4, FieldMemOperand(r1, JSFunction::kSharedFunctionInfoOffset));
  __ ldr(r4, FieldMemOperand(r4, SharedFunctionInfo::kFlagsOffset));
  __ DecodeField<SharedFunctionInfo::FunctionKindBits>(r4);
  __ JumpIfIsInRange(
      r4, r4, 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);
  __ b(&post_instantiation_deopt_entry);
 
  // Else: use TheHoleValue as receiver for constructor call
  __ bind(&not_create_implicit_receiver);
  __ LoadRoot(r0, RootIndex::kTheHoleValue);
 
  // ----------- S t a t e -------------
  //  --                          r0: receiver
  //  -- Slot 3 / sp[0*kPointerSize]: new target
  //  -- Slot 2 / sp[1*kPointerSize]: constructor function
  //  -- Slot 1 / sp[2*kPointerSize]: number of arguments
  //  -- Slot 0 / sp[3*kPointerSize]: context
  // -----------------------------------
  // Deoptimizer enters here.
  masm->isolate()->heap()->SetConstructStubCreateDeoptPCOffset(
      masm->pc_offset());
  __ bind(&post_instantiation_deopt_entry);
 
  // Restore new target.
  __ Pop(r3);
 
  // Push the allocated receiver to the stack.
  __ Push(r0);
  // 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 r6
  // since r0 needs to store the number of arguments before
  // InvokingFunction.
  __ mov(r6, r0);
 
  // Set up pointer to first argument (skip receiver).
  __ add(r4, fp,
         Operand(StandardFrameConstants::kCallerSPOffset + kSystemPointerSize));
 
  // Restore constructor function and argument count.
  __ ldr(r1, MemOperand(fp, ConstructFrameConstants::kConstructorOffset));
  __ ldr(r0, MemOperand(fp, ConstructFrameConstants::kLengthOffset));
 
  Label stack_overflow;
  __ StackOverflowCheck(r0, r5, &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 to the expression stack.
  // r4: Pointer to start of argument.
  // r0: Number of arguments.
  Generate_PushArguments(masm, r4, r0, r5, ArgumentsElementType::kRaw);
 
  // Push implicit receiver.
  __ Push(r6);
 
  // Call the function.
  __ InvokeFunctionWithNewTarget(r1, r3, r0, 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(r0, 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);
  __ ldr(r0, MemOperand(sp, 0 * kPointerSize));
  __ JumpIfRoot(r0, RootIndex::kTheHoleValue, &do_throw);
 
  __ bind(&leave_and_return);
  // Restore arguments count from the frame.
  __ ldr(r1, MemOperand(fp, ConstructFrameConstants::kLengthOffset));
  // Leave construct frame.
  __ LeaveFrame(StackFrame::CONSTRUCT);
 
  // Remove caller arguments from the stack and return.
  __ DropArguments(r1);
  __ Jump(lr);
 
  __ bind(&check_receiver);
  // If the result is a smi, it is *not* an object in the ECMA sense.
  __ JumpIfSmi(r0, &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.
  static_assert(LAST_JS_RECEIVER_TYPE == LAST_TYPE);
  __ CompareObjectType(r0, r4, r5, FIRST_JS_RECEIVER_TYPE);
  __ b(ge, &leave_and_return);
  __ b(&use_receiver);
 
  __ bind(&do_throw);
  // Restore the context from the frame.
  __ ldr(cp, MemOperand(fp, ConstructFrameConstants::kContextOffset));
  __ CallRuntime(Runtime::kThrowConstructorReturnedNonObject);
  __ bkpt(0);
 
  __ bind(&stack_overflow);
  // Restore the context from the frame.
  __ ldr(cp, MemOperand(fp, ConstructFrameConstants::kContextOffset));
  __ CallRuntime(Runtime::kThrowStackOverflow);
  // Unreachable code.
  __ bkpt(0);
}
 
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.
  __ ldr(scratch, FieldMemOperand(code, Code::kFlagsOffset));
  __ DecodeField<Code::KindField>(scratch);
  __ cmp(scratch, Operand(static_cast<int>(CodeKind::BASELINE)));
  __ Assert(eq, AbortReason::kExpectedBaselineData);
}
 
static void GetSharedFunctionInfoBytecodeOrBaseline(
    MacroAssembler* masm, Register sfi, Register bytecode, Register scratch1,
    Label* is_baseline, Label* is_unavailable) {
  ASM_CODE_COMMENT(masm);
  Label done;
 
  Register data = bytecode;
  __ ldr(data,
         FieldMemOperand(sfi, SharedFunctionInfo::kTrustedFunctionDataOffset));
 
  __ LoadMap(scratch1, data);
  __ ldrh(scratch1, FieldMemOperand(scratch1, Map::kInstanceTypeOffset));
 
#ifndef V8_JITLESS
  __ cmp(scratch1, Operand(CODE_TYPE));
  if (v8_flags.debug_code) {
    Label not_baseline;
    __ b(ne, &not_baseline);
    AssertCodeIsBaseline(masm, data, scratch1);
    __ b(eq, is_baseline);
    __ bind(&not_baseline);
  } else {
    __ b(eq, is_baseline);
  }
#endif  // !V8_JITLESS
 
  __ cmp(scratch1, Operand(BYTECODE_ARRAY_TYPE));
  __ b(eq, &done);
 
  __ cmp(scratch1, Operand(INTERPRETER_DATA_TYPE));
  __ b(ne, is_unavailable);
  __ ldr(data, FieldMemOperand(data, InterpreterData::kBytecodeArrayOffset));
 
  __ bind(&done);
}
 
// static
void Builtins::Generate_ResumeGeneratorTrampoline(MacroAssembler* masm) {
  // ----------- S t a t e -------------
  //  -- r0 : the value to pass to the generator
  //  -- r1 : the JSGeneratorObject to resume
  //  -- lr : return address
  // -----------------------------------
  // Store input value into generator object.
  __ str(r0, FieldMemOperand(r1, JSGeneratorObject::kInputOrDebugPosOffset));
  __ RecordWriteField(r1, JSGeneratorObject::kInputOrDebugPosOffset, r0,
                      kLRHasNotBeenSaved, SaveFPRegsMode::kIgnore);
  // Check that r1 is still valid, RecordWrite might have clobbered it.
  __ AssertGeneratorObject(r1);
 
  // Load suspended function and context.
  __ ldr(r4, FieldMemOperand(r1, JSGeneratorObject::kFunctionOffset));
  __ ldr(cp, FieldMemOperand(r4, JSFunction::kContextOffset));
 
  Label prepare_step_in_if_stepping, prepare_step_in_suspended_generator;
  Label stepping_prepared;
  Register scratch = r5;
 
  // Flood function if we are stepping.
  ExternalReference debug_hook =
      ExternalReference::debug_hook_on_function_call_address(masm->isolate());
  __ Move(scratch, debug_hook);
  __ ldrsb(scratch, MemOperand(scratch));
  __ cmp(scratch, Operand(0));
  __ b(ne, &prepare_step_in_if_stepping);
 
  // Flood function if we need to continue stepping in the suspended
  // generator.
  ExternalReference debug_suspended_generator =
      ExternalReference::debug_suspended_generator_address(masm->isolate());
  __ Move(scratch, debug_suspended_generator);
  __ ldr(scratch, MemOperand(scratch));
  __ cmp(scratch, Operand(r1));
  __ b(eq, &prepare_step_in_suspended_generator);
  __ bind(&stepping_prepared);
 
  // Check the stack for overflow. We are not trying to catch interruptions
  // (i.e. debug break and preemption) here, so check the "real stack limit".
  Label stack_overflow;
  __ LoadStackLimit(scratch, StackLimitKind::kRealStackLimit);
  __ cmp(sp, scratch);
  __ b(lo, &stack_overflow);
 
  // ----------- S t a t e -------------
  //  -- r1    : the JSGeneratorObject to resume
  //  -- r4    : generator function
  //  -- cp    : generator context
  //  -- lr    : return address
  //  -- sp[0] : generator receiver
  // -----------------------------------
 
  // Copy the function arguments from the generator object's register file.
  __ ldr(r3, FieldMemOperand(r4, JSFunction::kSharedFunctionInfoOffset));
  __ ldrh(r3,
          FieldMemOperand(r3, SharedFunctionInfo::kFormalParameterCountOffset));
  __ sub(r3, r3, Operand(kJSArgcReceiverSlots));
  __ ldr(r2,
         FieldMemOperand(r1, JSGeneratorObject::kParametersAndRegistersOffset));
  {
    Label done_loop, loop;
    __ bind(&loop);
    __ sub(r3, r3, Operand(1), SetCC);
    __ b(lt, &done_loop);
    __ add(scratch, r2, Operand(r3, LSL, kTaggedSizeLog2));
    __ ldr(scratch, FieldMemOperand(scratch, OFFSET_OF_DATA_START(FixedArray)));
    __ Push(scratch);
    __ b(&loop);
    __ bind(&done_loop);
 
    // Push receiver.
    __ ldr(scratch, FieldMemOperand(r1, JSGeneratorObject::kReceiverOffset));
    __ Push(scratch);
  }
 
  // Underlying function needs to have bytecode available.
  if (v8_flags.debug_code) {
    Label is_baseline, is_unavailable, ok;
    __ ldr(r3, FieldMemOperand(r4, JSFunction::kSharedFunctionInfoOffset));
    GetSharedFunctionInfoBytecodeOrBaseline(masm, r3, r3, r0, &is_baseline,
                                            &is_unavailable);
    __ jmp(&ok);
 
    __ bind(&is_unavailable);
    __ Abort(AbortReason::kMissingBytecodeArray);
 
    __ bind(&is_baseline);
    __ CompareObjectType(r3, r3, r3, CODE_TYPE);
    __ Assert(eq, AbortReason::kMissingBytecodeArray);
 
    __ bind(&ok);
  }
 
  // Resume (Ignition/TurboFan) generator object.
  {
    __ ldr(r0, FieldMemOperand(r4, JSFunction::kSharedFunctionInfoOffset));
    __ ldrh(r0, FieldMemOperand(
                    r0, 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(r3, r1);
    __ Move(r1, r4);
    __ JumpJSFunction(r1);
  }
 
  __ bind(&prepare_step_in_if_stepping);
  {
    FrameAndConstantPoolScope scope(masm, StackFrame::INTERNAL);
    __ Push(r1, r4);
    // Push hole as receiver since we do not use it for stepping.
    __ PushRoot(RootIndex::kTheHoleValue);
    __ CallRuntime(Runtime::kDebugOnFunctionCall);
    __ Pop(r1);
    __ ldr(r4, FieldMemOperand(r1, JSGeneratorObject::kFunctionOffset));
  }
  __ b(&stepping_prepared);
 
  __ bind(&prepare_step_in_suspended_generator);
  {
    FrameAndConstantPoolScope scope(masm, StackFrame::INTERNAL);
    __ Push(r1);
    __ CallRuntime(Runtime::kDebugPrepareStepInSuspendedGenerator);
    __ Pop(r1);
    __ ldr(r4, FieldMemOperand(r1, JSGeneratorObject::kFunctionOffset));
  }
  __ b(&stepping_prepared);
 
  __ bind(&stack_overflow);
  {
    FrameScope scope(masm, StackFrame::INTERNAL);
    __ CallRuntime(Runtime::kThrowStackOverflow);
    __ bkpt(0);  // This should be unreachable.
  }
}
 
void Builtins::Generate_ConstructedNonConstructable(MacroAssembler* masm) {
  FrameScope scope(masm, StackFrame::INTERNAL);
  __ push(r1);
  __ CallRuntime(Runtime::kThrowConstructedNonConstructable);
}
 
namespace {
 
// Total size of the stack space pushed by JSEntryVariant.
// JSEntryTrampoline uses this to access on stack arguments passed to
// JSEntryVariant.
constexpr int kPushedStackSpace =
    kNumCalleeSaved * kPointerSize - kPointerSize /* FP */ +
    kNumDoubleCalleeSaved * kDoubleSize +
    7 * kPointerSize /* r5, r6, r7, r8, r9, fp, lr */ +
    EntryFrameConstants::kNextFastCallFramePCOffset;
 
// Assert that the EntryFrameConstants are in sync with the builtin.
static_assert(kPushedStackSpace ==
                  EntryFrameConstants::kDirectCallerSPOffset +
                      5 * kPointerSize /* r5, r6, r7, r8, r9*/ +
                      EntryFrameConstants::kNextFastCallFramePCOffset,
              "Pushed stack space and frame constants do not match. See "
              "frame-constants-arm.h");
 
// Called with the native C calling convention. The corresponding function
// signature is either:
//
//   using JSEntryFunction = GeneratedCode<Address(
//       Address root_register_value, Address new_target, Address target,
//       Address receiver, intptr_t argc, Address** argv)>;
// or
//   using JSEntryFunction = GeneratedCode<Address(
//       Address root_register_value, MicrotaskQueue* microtask_queue)>;
void Generate_JSEntryVariant(MacroAssembler* masm, StackFrame::Type type,
                             Builtin entry_trampoline) {
  // The register state is either:
  //   r0:                            root_register_value
  //   r1:                            code entry
  //   r2:                            function
  //   r3:                            receiver
  //   [sp + 0 * kSystemPointerSize]: argc
  //   [sp + 1 * kSystemPointerSize]: argv
  // or
  //   r0: root_register_value
  //   r1: microtask_queue
  // Preserve all but r0 and pass them to entry_trampoline.
  Label invoke, handler_entry, exit;
  const RegList kCalleeSavedWithoutFp = kCalleeSaved - fp;
 
  // Update |pushed_stack_space| when we manipulate the stack.
  int pushed_stack_space = EntryFrameConstants::kNextFastCallFramePCOffset;
  {
    NoRootArrayScope no_root_array(masm);
 
    // Called from C, so do not pop argc and args on exit (preserve sp)
    // No need to save register-passed args
    // Save callee-saved registers (incl. cp), but without fp
    __ stm(db_w, sp, kCalleeSavedWithoutFp);
    pushed_stack_space +=
        kNumCalleeSaved * kPointerSize - kPointerSize /* FP */;
 
    // Save callee-saved vfp registers.
    __ vstm(db_w, sp, kFirstCalleeSavedDoubleReg, kLastCalleeSavedDoubleReg);
    pushed_stack_space += kNumDoubleCalleeSaved * kDoubleSize;
 
    // Set up the reserved register for 0.0.
    __ vmov(kDoubleRegZero, base::Double(0.0));
 
    // Initialize the root register.
    // C calling convention. The first argument is passed in r0.
    __ mov(kRootRegister, r0);
  }
 
  // r0: root_register_value
 
  // Push a frame with special values setup to mark it as an entry frame.
  // 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.
  __ mov(r9, Operand::Zero());
  __ Move(r4, ExternalReference::Create(IsolateAddressId::kCEntryFPAddress,
                                        masm->isolate()));
  __ ldr(r7, MemOperand(r4));
  __ str(r9, MemOperand(r4));
 
  __ LoadIsolateField(r4, IsolateFieldId::kFastCCallCallerFP);
  __ ldr(r6, MemOperand(r4));
  __ str(r9, MemOperand(r4));
 
  __ LoadIsolateField(r4, IsolateFieldId::kFastCCallCallerPC);
  __ ldr(r5, MemOperand(r4));
  __ str(r9, MemOperand(r4));
 
  __ mov(r9, Operand(StackFrame::TypeToMarker(type)));
  __ mov(r8, Operand(StackFrame::TypeToMarker(type)));
  __ stm(db_w, sp, {r5, r6, r7, r8, r9, fp, lr});
  pushed_stack_space += 7 * kPointerSize /* r5, r6, r7, r8, r9, fp, lr */;
 
  Register scratch = r6;
 
  // Set up frame pointer for the frame to be pushed.
  __ add(fp, sp, Operand(-EntryFrameConstants::kNextFastCallFramePCOffset));
 
  // 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());
  __ Move(r5, js_entry_sp);
  __ ldr(scratch, MemOperand(r5));
  __ cmp(scratch, Operand::Zero());
  __ b(ne, &non_outermost_js);
  __ str(fp, MemOperand(r5));
  __ mov(scratch, Operand(StackFrame::OUTERMOST_JSENTRY_FRAME));
  Label cont;
  __ b(&cont);
  __ bind(&non_outermost_js);
  __ mov(scratch, Operand(StackFrame::INNER_JSENTRY_FRAME));
  __ bind(&cont);
  __ push(scratch);
 
  // Jump to a faked try block that does the invoke, with a faked catch
  // block that sets the exception.
  __ jmp(&invoke);
 
  // Block literal pool emission whilst taking the position of the handler
  // entry. This avoids making the assumption that literal pools are always
  // emitted after an instruction is emitted, rather than before.
  {
    Assembler::BlockConstPoolScope block_const_pool(masm);
    __ 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.
    __ Move(scratch, ExternalReference::Create(
                         IsolateAddressId::kExceptionAddress, masm->isolate()));
  }
  __ str(r0, MemOperand(scratch));
  __ LoadRoot(r0, RootIndex::kException);
  __ b(&exit);
 
  // Invoke: Link this frame into the handler chain.
  __ bind(&invoke);
  // Must preserve r0-r4, r5-r6 are available.
  __ PushStackHandler();
  // If an exception not caught by another handler occurs, this handler
  // returns control to the code after the bl(&invoke) above, which
  // restores all kCalleeSaved registers (including cp and fp) to their
  // saved values before returning a failure to C.
  //
  // Invoke the function by calling through JS entry trampoline builtin and
  // pop the faked function when we return.
  DCHECK_EQ(kPushedStackSpace, pushed_stack_space);
  USE(pushed_stack_space);
  __ CallBuiltin(entry_trampoline);
 
  // Unlink this frame from the handler chain.
  __ PopStackHandler();
 
  __ bind(&exit);  // r0 holds result
  // Check if the current stack frame is marked as the outermost JS frame.
  Label non_outermost_js_2;
  __ pop(r5);
  __ cmp(r5, Operand(StackFrame::OUTERMOST_JSENTRY_FRAME));
  __ b(ne, &non_outermost_js_2);
  __ mov(r6, Operand::Zero());
  __ Move(r5, js_entry_sp);
  __ str(r6, MemOperand(r5));
  __ bind(&non_outermost_js_2);
 
  // Restore the top frame descriptors from the stack.
  __ ldm(ia_w, sp, {r3, r4, r5});
  __ LoadIsolateField(scratch, IsolateFieldId::kFastCCallCallerFP);
  __ str(r4, MemOperand(scratch));
 
  __ LoadIsolateField(scratch, IsolateFieldId::kFastCCallCallerPC);
  __ str(r3, MemOperand(scratch));
 
  __ Move(scratch, ExternalReference::Create(IsolateAddressId::kCEntryFPAddress,
                                             masm->isolate()));
  __ str(r5, MemOperand(scratch));
 
  // Reset the stack to the callee saved registers.
  __ add(sp, sp,
         Operand(-EntryFrameConstants::kNextExitFrameFPOffset -
                 kSystemPointerSize /* already popped the exit frame FP */));
 
  __ ldm(ia_w, sp, {fp, lr});
 
  // Restore callee-saved vfp registers.
  __ vldm(ia_w, sp, kFirstCalleeSavedDoubleReg, kLastCalleeSavedDoubleReg);
 
  __ ldm(ia_w, sp, kCalleeSavedWithoutFp);
 
  __ mov(pc, lr);
 
  // Emit constant pool.
  __ CheckConstPool(true, false);
}
 
}  // 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) {
  // Called from Generate_JS_Entry
  // r0:                                                root_register_value
  // r1:                                                new.target
  // r2:                                                function
  // r3:                                                receiver
  // [fp + kPushedStackSpace + 0 * kSystemPointerSize]: argc
  // [fp + kPushedStackSpace + 1 * kSystemPointerSize]: argv
  // r5-r6, r8 and cp may be clobbered
 
  __ ldr(r0,
         MemOperand(fp, kPushedStackSpace + EntryFrameConstants::kArgcOffset));
  __ ldr(r4,
         MemOperand(fp, kPushedStackSpace + EntryFrameConstants::kArgvOffset));
 
  // r1: new.target
  // r2: function
  // r3: receiver
  // r0: argc
  // r4: 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());
    __ Move(cp, context_address);
    __ ldr(cp, MemOperand(cp));
 
    // Push the function.
    __ Push(r2);
 
    // Check if we have enough stack space to push all arguments + receiver.
    // Clobbers r5.
    Label enough_stack_space, stack_overflow;
    __ mov(r6, r0);
    __ StackOverflowCheck(r6, r5, &stack_overflow);
    __ b(&enough_stack_space);
    __ bind(&stack_overflow);
    __ CallRuntime(Runtime::kThrowStackOverflow);
    // Unreachable code.
    __ bkpt(0);
 
    __ bind(&enough_stack_space);
 
    // Copy arguments to the stack.
    // r1: new.target
    // r2: function
    // r3: receiver
    // r0: argc
    // r4: argv, i.e. points to first arg
    Generate_PushArguments(masm, r4, r0, r5, ArgumentsElementType::kHandle);
 
    // Push the receiver.
    __ Push(r3);
 
    // Setup new.target and function.
    __ mov(r3, r1);
    __ mov(r1, r2);
    // r0: argc
    // r1: function
    // r3: new.target
 
    // Initialize all JavaScript callee-saved registers, since they will be seen
    // by the garbage collector as part of handlers.
    __ LoadRoot(r4, RootIndex::kUndefinedValue);
    __ mov(r2, r4);
    __ mov(r5, r4);
    __ mov(r6, r4);
    __ mov(r8, r4);
    __ mov(r9, r4);
 
    // Invoke the code.
    Builtin builtin = is_construct ? Builtin::kConstruct : Builtins::Call();
    __ CallBuiltin(builtin);
 
    // Exit the JS frame and remove the parameters (except function), and
    // return.
    // Respect ABI stack constraint.
  }
  __ Jump(lr);
 
  // r0: result
}
 
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) {
  // This expects two C++ function parameters passed by Invoke() in
  // execution.cc.
  //   r0: root_register_value
  //   r1: microtask_queue
 
  __ mov(RunMicrotasksDescriptor::MicrotaskQueueRegister(), r1);
  __ 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).
  __ ldr(params_size,
         MemOperand(fp, InterpreterFrameConstants::kBytecodeArrayFromFp));
  __ ldrh(params_size,
          FieldMemOperand(params_size, BytecodeArray::kParameterSizeOffset));
 
  Register actual_params_size = scratch2;
  // Compute the size of the actual parameters + receiver (in bytes).
  __ ldr(actual_params_size,
         MemOperand(fp, StandardFrameConstants::kArgCOffset));
 
  // If actual is bigger than formal, then we should use it to free up the stack
  // arguments.
  __ cmp(params_size, actual_params_size);
  __ mov(params_size, actual_params_size, LeaveCC, kLessThan);
 
  // 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, 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 = scratch2;
  DCHECK(!AreAliased(bytecode_array, bytecode_offset, bytecode_size_table,
                     bytecode, original_bytecode_offset));
 
  __ Move(bytecode_size_table,
          ExternalReference::bytecode_size_table_address());
  __ Move(original_bytecode_offset, bytecode_offset);
 
  // Check if the bytecode is a Wide or ExtraWide prefix bytecode.
  Label process_bytecode;
  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));
  __ cmp(bytecode, Operand(0x3));
  __ b(hi, &process_bytecode);
  __ tst(bytecode, Operand(0x1));
  // Load the next bytecode.
  __ add(bytecode_offset, bytecode_offset, Operand(1));
  __ ldrb(bytecode, MemOperand(bytecode_array, bytecode_offset));
 
  // Update table to the wide scaled table.
  __ add(bytecode_size_table, bytecode_size_table,
         Operand(kByteSize * interpreter::Bytecodes::kBytecodeCount));
  // Conditionally update table to the extra wide scaled table. We are taking
  // advantage of the fact that the extra wide follows the wide one.
  __ add(bytecode_size_table, bytecode_size_table,
         Operand(kByteSize * interpreter::Bytecodes::kBytecodeCount), LeaveCC,
         ne);
 
  __ bind(&process_bytecode);
 
  // Bailout to the return label if this is a return bytecode.
 
  // Create cmp, cmpne, ..., cmpne to check for a return bytecode.
  Condition flag = al;
#define JUMP_IF_EQUAL(NAME)                                                   \
  __ cmp(bytecode, Operand(static_cast<int>(interpreter::Bytecode::k##NAME)), \
         flag);                                                               \
  flag = ne;
  RETURN_BYTECODE_LIST(JUMP_IF_EQUAL)
#undef JUMP_IF_EQUAL
 
  __ b(if_return, eq);
 
  // If this is a JumpLoop, re-execute it to perform the jump to the beginning
  // of the loop.
  Label end, not_jump_loop;
  __ cmp(bytecode, Operand(static_cast<int>(interpreter::Bytecode::kJumpLoop)));
  __ b(ne, &not_jump_loop);
  // 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);
  __ b(&end);
 
  __ bind(&not_jump_loop);
  // Otherwise, load the size of the current bytecode and advance the offset.
  __ ldrb(scratch1, MemOperand(bytecode_size_table, bytecode));
  __ add(bytecode_offset, bytecode_offset, scratch1);
 
  __ bind(&end);
}
 
namespace {
 
void ResetSharedFunctionInfoAge(MacroAssembler* masm, Register sfi,
                                Register scratch) {
  DCHECK(!AreAliased(sfi, scratch));
  __ mov(scratch, Operand(0));
  __ strh(scratch, FieldMemOperand(sfi, SharedFunctionInfo::kAgeOffset));
}
 
void ResetJSFunctionAge(MacroAssembler* masm, Register js_function,
                        Register scratch1, Register scratch2) {
  __ Move(scratch1,
          FieldMemOperand(js_function, JSFunction::kSharedFunctionInfoOffset));
  ResetSharedFunctionInfoAge(masm, scratch1, scratch2);
}
 
void ResetFeedbackVectorOsrUrgency(MacroAssembler* masm,
                                   Register feedback_vector, Register scratch) {
  DCHECK(!AreAliased(feedback_vector, scratch));
  __ ldrb(scratch,
          FieldMemOperand(feedback_vector, FeedbackVector::kOsrStateOffset));
  __ and_(scratch, scratch, Operand(~FeedbackVector::OsrUrgencyBits::kMask));
  __ strb(scratch,
          FieldMemOperand(feedback_vector, FeedbackVector::kOsrStateOffset));
}
 
}  // namespace
 
// static
void Builtins::Generate_BaselineOutOfLinePrologue(MacroAssembler* masm) {
  UseScratchRegisterScope temps(masm);
  // Need a few extra registers
  temps.Include({r4, r5, r8, r9});
 
  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();
  __ ldr(feedback_cell,
         FieldMemOperand(closure, JSFunction::kFeedbackCellOffset));
  __ ldr(feedback_vector,
         FieldMemOperand(feedback_cell, FeedbackCell::kValueOffset));
  {
    UseScratchRegisterScope temps(masm);
    Register temporary = temps.Acquire();
    __ AssertFeedbackVector(feedback_vector, temporary);
  }
 
#ifndef V8_ENABLE_LEAPTIERING
  // Check the tiering state.
  Label flags_need_processing;
  Register flags = no_reg;
  {
    UseScratchRegisterScope temps(masm);
    // flags will be used only in |flags_need_processing|
    // and outside it can be reused.
    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();
    __ ldr(invocation_count,
           FieldMemOperand(feedback_vector,
                           FeedbackVector::kInvocationCountOffset));
    __ add(invocation_count, invocation_count, Operand(1));
    __ str(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(lr, fp), but we already
    // entered the frame in BaselineCompiler::Prologue, as we had to use the
    // value lr 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(),
                         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 bytecodeArray = descriptor.GetRegisterParameter(
        BaselineOutOfLinePrologueDescriptor::kInterpreterBytecodeArray);
    __ Push(argc, bytecodeArray);
    if (v8_flags.debug_code) {
      UseScratchRegisterScope temps(masm);
      Register scratch = temps.Acquire();
      __ CompareObjectType(feedback_vector, scratch, scratch,
                           FEEDBACK_VECTOR_TYPE);
      __ Assert(eq, AbortReason::kExpectedFeedbackVector);
    }
    __ Push(feedback_cell);
    __ Push(feedback_vector);
  }
 
  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();
    __ sub(sp_minus_frame_size, sp, frame_size);
    Register interrupt_limit = temps.Acquire();
    __ LoadStackLimit(interrupt_limit, StackLimitKind::kInterruptStackLimit);
    __ cmp(sp_minus_frame_size, interrupt_limit);
    __ b(&call_stack_guard, lo);
  }
 
  // Do "fast" return to the caller pc in lr.
  __ LoadRoot(kInterpreterAccumulatorRegister, RootIndex::kUndefinedValue);
  __ Ret();
 
#ifndef V8_ENABLE_LEAPTIERING
  __ bind(&flags_need_processing);
  {
    ASM_CODE_COMMENT_STRING(masm, "Optimized marker check");
    UseScratchRegisterScope temps(masm);
    // Ensure the flags is not allocated again.
    temps.Exclude(flags);
 
    // Drop the frame created by the baseline call.
    __ ldm(ia_w, sp, {fp, lr});
    __ 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);
    __ SmiTag(frame_size);
    __ Push(frame_size);
    __ CallRuntime(Runtime::kStackGuardWithGap);
    __ Pop(kJavaScriptCallNewTargetRegister);
  }
 
  __ LoadRoot(kInterpreterAccumulatorRegister, RootIndex::kUndefinedValue);
  __ Ret();
}
 
// 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 the feedback vector, the bytecode offset (was the feedback vector but
  // got replaced during deopt) and bytecode array.
  __ Drop(3);
 
  // 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 r0: actual argument count
//   o r1: the JS function object being called.
//   o r3: the incoming new target or generator object
//   o cp: our context
//   o fp: the caller's frame pointer
//   o sp: stack pointer
//   o lr: return address
//
// The function builds an interpreter frame. See InterpreterFrameConstants in
// frame-constants.h for its layout.
void Builtins::Generate_InterpreterEntryTrampoline(
    MacroAssembler* masm, InterpreterEntryTrampolineMode mode) {
  Register closure = r1;
 
  // Get the bytecode array from the function object and load it into
  // kInterpreterBytecodeArrayRegister.
  __ ldr(r4, FieldMemOperand(closure, JSFunction::kSharedFunctionInfoOffset));
  ResetSharedFunctionInfoAge(masm, r4, r8);
 
  // The bytecode array could have been flushed from the shared function info,
  // if so, call into CompileLazy.
  Label is_baseline, compile_lazy;
  GetSharedFunctionInfoBytecodeOrBaseline(masm, r4,
                                          kInterpreterBytecodeArrayRegister, r8,
                                          &is_baseline, &compile_lazy);
 
  Label push_stack_frame;
  Register feedback_vector = r2;
  __ LoadFeedbackVector(feedback_vector, closure, r4, &push_stack_frame);
 
#ifndef V8_JITLESS
#ifndef V8_ENABLE_LEAPTIERING
  // If feedback vector is valid, check for optimized code and update invocation
  // count.
  Register flags = r4;
  Label flags_need_processing;
  __ LoadFeedbackVectorFlagsAndJumpIfNeedsProcessing(
      flags, feedback_vector, CodeKind::INTERPRETED_FUNCTION,
      &flags_need_processing);
#endif  // !V8_ENABLE_LEAPTIERING
 
  ResetFeedbackVectorOsrUrgency(masm, feedback_vector, r4);
 
  // Increment invocation count for the function.
  __ ldr(r9, FieldMemOperand(feedback_vector,
                             FeedbackVector::kInvocationCountOffset));
  __ add(r9, r9, Operand(1));
  __ str(r9, 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 the initial bytecode offset.
  __ mov(kInterpreterBytecodeOffsetRegister,
         Operand(BytecodeArray::kHeaderSize - kHeapObjectTag));
 
  // Push bytecode array and Smi tagged bytecode array offset.
  __ SmiTag(r4, kInterpreterBytecodeOffsetRegister);
  __ Push(kInterpreterBytecodeArrayRegister, r4, feedback_vector);
 
  // Allocate the local and temporary register file on the stack.
  Label stack_overflow;
  {
    // Load frame size from the BytecodeArray object.
    __ ldr(r4, FieldMemOperand(kInterpreterBytecodeArrayRegister,
                               BytecodeArray::kFrameSizeOffset));
 
    // Do a stack check to ensure we don't go over the limit.
    __ sub(r9, sp, Operand(r4));
    __ LoadStackLimit(r2, StackLimitKind::kRealStackLimit);
    __ cmp(r9, Operand(r2));
    __ b(lo, &stack_overflow);
 
    // If ok, push undefined as the initial value for all register file entries.
    Label loop_header;
    Label loop_check;
    __ LoadRoot(kInterpreterAccumulatorRegister, RootIndex::kUndefinedValue);
    __ b(&loop_check, al);
    __ bind(&loop_header);
    // TODO(rmcilroy): Consider doing more than one push per loop iteration.
    __ push(kInterpreterAccumulatorRegister);
    // Continue loop if not done.
    __ bind(&loop_check);
    __ sub(r4, r4, Operand(kPointerSize), SetCC);
    __ b(&loop_header, ge);
  }
 
  // If the bytecode array has a valid incoming new target or generator object
  // register, initialize it with incoming value which was passed in r3.
  __ ldr(r9, FieldMemOperand(
                 kInterpreterBytecodeArrayRegister,
                 BytecodeArray::kIncomingNewTargetOrGeneratorRegisterOffset));
  __ cmp(r9, Operand::Zero());
  __ str(r3, MemOperand(fp, r9, LSL, kPointerSizeLog2), ne);
 
  // Perform interrupt stack check.
  // TODO(solanes): Merge with the real stack limit check above.
  Label stack_check_interrupt, after_stack_check_interrupt;
  __ LoadStackLimit(r4, StackLimitKind::kInterruptStackLimit);
  __ cmp(sp, r4);
  __ b(lo, &stack_check_interrupt);
  __ bind(&after_stack_check_interrupt);
 
  // The accumulator is already loaded with undefined.
 
  // Load the dispatch table into a register and dispatch to the bytecode
  // handler at the current bytecode offset.
  Label do_dispatch;
  __ bind(&do_dispatch);
  __ Move(
      kInterpreterDispatchTableRegister,
      ExternalReference::interpreter_dispatch_table_address(masm->isolate()));
  __ ldrb(r4, MemOperand(kInterpreterBytecodeArrayRegister,
                         kInterpreterBytecodeOffsetRegister));
  __ ldr(
      kJavaScriptCallCodeStartRegister,
      MemOperand(kInterpreterDispatchTableRegister, r4, LSL, kPointerSizeLog2));
  __ 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.
  __ ldr(kInterpreterBytecodeArrayRegister,
         MemOperand(fp, InterpreterFrameConstants::kBytecodeArrayFromFp));
  __ ldr(kInterpreterBytecodeOffsetRegister,
         MemOperand(fp, InterpreterFrameConstants::kBytecodeOffsetFromFp));
  __ SmiUntag(kInterpreterBytecodeOffsetRegister);
 
  // Either return, or advance to the next bytecode and dispatch.
  Label do_return;
  __ ldrb(r1, MemOperand(kInterpreterBytecodeArrayRegister,
                         kInterpreterBytecodeOffsetRegister));
  AdvanceBytecodeOffsetOrReturn(masm, kInterpreterBytecodeArrayRegister,
                                kInterpreterBytecodeOffsetRegister, r1, r2, r3,
                                &do_return);
  __ jmp(&do_dispatch);
 
  __ bind(&do_return);
  // The return value is in r0.
  LeaveInterpreterFrame(masm, r2, r4);
  __ Jump(lr);
 
  __ bind(&stack_check_interrupt);
  // Modify the bytecode offset in the stack to be kFunctionEntryBytecodeOffset
  // for the call to the StackGuard.
  __ mov(kInterpreterBytecodeOffsetRegister,
         Operand(Smi::FromInt(BytecodeArray::kHeaderSize - kHeapObjectTag +
                              kFunctionEntryBytecodeOffset)));
  __ str(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.
  __ ldr(kInterpreterBytecodeArrayRegister,
         MemOperand(fp, InterpreterFrameConstants::kBytecodeArrayFromFp));
  __ mov(kInterpreterBytecodeOffsetRegister,
         Operand(BytecodeArray::kHeaderSize - kHeapObjectTag));
  __ LoadRoot(kInterpreterAccumulatorRegister, RootIndex::kUndefinedValue);
 
  __ SmiTag(r4, kInterpreterBytecodeOffsetRegister);
  __ str(r4, MemOperand(fp, InterpreterFrameConstants::kBytecodeOffsetFromFp));
 
  __ jmp(&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.
    __ ldr(feedback_vector,
           FieldMemOperand(closure, JSFunction::kFeedbackCellOffset));
    __ ldr(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.
    __ ldr(r8, FieldMemOperand(feedback_vector, HeapObject::kMapOffset));
    __ ldrh(r8, FieldMemOperand(r8, Map::kInstanceTypeOffset));
    __ cmp(r8, Operand(FEEDBACK_VECTOR_TYPE));
    __ b(ne, &install_baseline_code);
 
    // Check the tiering state.
    __ LoadFeedbackVectorFlagsAndJumpIfNeedsProcessing(
        flags, feedback_vector, CodeKind::BASELINE, &flags_need_processing);
 
    // oad the baseline code into the closure.
    __ mov(r2, kInterpreterBytecodeArrayRegister);
    static_assert(kJavaScriptCallCodeStartRegister == r2, "ABI mismatch");
    __ ReplaceClosureCodeWithOptimizedCode(r2, closure);
    __ JumpCodeObject(r2);
 
    __ bind(&install_baseline_code);
#endif  // !V8_ENABLE_LEAPTIERING
    __ GenerateTailCallToReturnedCode(Runtime::kInstallBaselineCode);
  }
#endif  // !V8_JITLESS
 
  __ bind(&compile_lazy);
  __ GenerateTailCallToReturnedCode(Runtime::kCompileLazy);
 
  __ bind(&stack_overflow);
  __ CallRuntime(Runtime::kThrowStackOverflow);
  __ bkpt(0);  // Should not return.
}
 
static void GenerateInterpreterPushArgs(MacroAssembler* masm, Register num_args,
                                        Register start_address,
                                        Register scratch) {
  ASM_CODE_COMMENT(masm);
  // Find the argument with lowest address.
  __ sub(scratch, num_args, Operand(1));
  __ mov(scratch, Operand(scratch, LSL, kSystemPointerSizeLog2));
  __ sub(start_address, start_address, scratch);
  // Push the arguments.
  __ PushArray(start_address, num_args, scratch,
               MacroAssembler::PushArrayOrder::kReverse);
}
 
// static
void Builtins::Generate_InterpreterPushArgsThenCallImpl(
    MacroAssembler* masm, ConvertReceiverMode receiver_mode,
    InterpreterPushArgsMode mode) {
  DCHECK(mode != InterpreterPushArgsMode::kArrayFunction);
  // ----------- S t a t e -------------
  //  -- r0 : the number of arguments
  //  -- r2 : 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.
  //  -- r1 : the target to call (can be any Object).
  // -----------------------------------
  Label stack_overflow;
 
  if (mode == InterpreterPushArgsMode::kWithFinalSpread) {
    // The spread argument should not be pushed.
    __ sub(r0, r0, Operand(1));
  }
 
  if (receiver_mode == ConvertReceiverMode::kNullOrUndefined) {
    __ sub(r3, r0, Operand(kJSArgcReceiverSlots));
  } else {
    __ mov(r3, r0);
  }
 
  __ StackOverflowCheck(r3, r4, &stack_overflow);
 
  // Push the arguments. r2 and r4 will be modified.
  GenerateInterpreterPushArgs(masm, r3, r2, r4);
 
  // Push "undefined" as the receiver arg if we need to.
  if (receiver_mode == ConvertReceiverMode::kNullOrUndefined) {
    __ PushRoot(RootIndex::kUndefinedValue);
  }
 
  if (mode == InterpreterPushArgsMode::kWithFinalSpread) {
    // Pass the spread in the register r2.
    // r2 already points to the penultimate argument, the spread
    // lies in the next interpreter register.
    __ sub(r2, r2, Operand(kSystemPointerSize));
    __ ldr(r2, MemOperand(r2));
  }
 
  // Call the target.
  if (mode == InterpreterPushArgsMode::kWithFinalSpread) {
    __ TailCallBuiltin(Builtin::kCallWithSpread);
  } else {
    __ TailCallBuiltin(Builtins::Call(receiver_mode));
  }
 
  __ bind(&stack_overflow);
  {
    __ TailCallRuntime(Runtime::kThrowStackOverflow);
    // Unreachable code.
    __ bkpt(0);
  }
}
 
// static
void Builtins::Generate_InterpreterPushArgsThenConstructImpl(
    MacroAssembler* masm, InterpreterPushArgsMode mode) {
  // ----------- S t a t e -------------
  // -- r0 : argument count
  // -- r3 : new target
  // -- r1 : constructor to call
  // -- r2 : allocation site feedback if available, undefined otherwise.
  // -- r4 : address of the first argument
  // -----------------------------------
  Label stack_overflow;
 
  __ StackOverflowCheck(r0, r6, &stack_overflow);
 
  if (mode == InterpreterPushArgsMode::kWithFinalSpread) {
    // The spread argument should not be pushed.
    __ sub(r0, r0, Operand(1));
  }
 
  Register argc_without_receiver = r6;
  __ sub(argc_without_receiver, r0, Operand(kJSArgcReceiverSlots));
  // Push the arguments. r4 and r5 will be modified.
  GenerateInterpreterPushArgs(masm, argc_without_receiver, r4, r5);
 
  // Push a slot for the receiver to be constructed.
  __ mov(r5, Operand::Zero());
  __ push(r5);
 
  if (mode == InterpreterPushArgsMode::kWithFinalSpread) {
    // Pass the spread in the register r2.
    // r4 already points to the penultimate argument, the spread
    // lies in the next interpreter register.
    __ sub(r4, r4, Operand(kSystemPointerSize));
    __ ldr(r2, MemOperand(r4));
  } else {
    __ AssertUndefinedOrAllocationSite(r2, r5);
  }
 
  if (mode == InterpreterPushArgsMode::kArrayFunction) {
    __ AssertFunction(r1);
 
    // Tail call to the array construct stub (still in the caller
    // context at this point).
    __ TailCallBuiltin(Builtin::kArrayConstructorImpl);
  } else if (mode == InterpreterPushArgsMode::kWithFinalSpread) {
    // Call the constructor with r0, r1, and r3 unmodified.
    __ TailCallBuiltin(Builtin::kConstructWithSpread);
  } else {
    DCHECK_EQ(InterpreterPushArgsMode::kOther, mode);
    // Call the constructor with r0, r1, and r3 unmodified.
    __ TailCallBuiltin(Builtin::kConstruct);
  }
 
  __ bind(&stack_overflow);
  {
    __ TailCallRuntime(Runtime::kThrowStackOverflow);
    // Unreachable code.
    __ bkpt(0);
  }
}
 
// static
void Builtins::Generate_ConstructForwardAllArgsImpl(
    MacroAssembler* masm, ForwardWhichFrame which_frame) {
  // ----------- S t a t e -------------
  // -- r3 : new target
  // -- r1 : constructor to call
  // -----------------------------------
  Label stack_overflow;
 
  // Load the frame pointer into r4.
  switch (which_frame) {
    case ForwardWhichFrame::kCurrentFrame:
      __ mov(r4, fp);
      break;
    case ForwardWhichFrame::kParentFrame:
      __ ldr(r4, MemOperand(fp, StandardFrameConstants::kCallerFPOffset));
      break;
  }
 
  // Load the argument count into r0.
  __ ldr(r0, MemOperand(r4, StandardFrameConstants::kArgCOffset));
 
  __ StackOverflowCheck(r0, r6, &stack_overflow);
 
  // Point r4 to the base of the argument list to forward, excluding the
  // receiver.
  __ add(r4, r4,
         Operand((StandardFrameConstants::kFixedSlotCountAboveFp + 1) *
                 kSystemPointerSize));
 
  // Copy arguments on the stack. r5 is a scratch register.
  Register argc_without_receiver = r6;
  __ sub(argc_without_receiver, r0, Operand(kJSArgcReceiverSlots));
  __ PushArray(r4, argc_without_receiver, r5);
 
  // Push a slot for the receiver to be constructed.
  __ mov(r5, Operand::Zero());
  __ push(r5);
 
  // Call the constructor with r0, r1, and r3 unmodified.
  __ TailCallBuiltin(Builtin::kConstruct);
 
  __ bind(&stack_overflow);
  {
    __ TailCallRuntime(Runtime::kThrowStackOverflow);
    // Unreachable code.
    __ bkpt(0);
  }
}
 
namespace {
 
void NewImplicitReceiver(MacroAssembler* masm) {
  // ----------- S t a t e -------------
  // -- r0 : argument count
  // -- r1 : constructor to call (checked to be a JSFunction)
  // -- r3 : new target
  //
  //  Stack:
  //  -- Implicit Receiver
  //  -- [arguments without receiver]
  //  -- Implicit Receiver
  //  -- Context
  //  -- FastConstructMarker
  //  -- FramePointer
  // -----------------------------------
  Register implicit_receiver = r4;
 
  // Save live registers.
  __ SmiTag(r0);
  __ Push(r0, r1, r3);
  __ CallBuiltin(Builtin::kFastNewObject);
  // Save result.
  __ Move(implicit_receiver, r0);
  // Restore live registers.
  __ Pop(r0, r1, r3);
  __ SmiUntag(r0);
 
  // Patch implicit receiver (in arguments)
  __ str(implicit_receiver, MemOperand(sp, 0 * kPointerSize));
  // Patch second implicit (in construct frame)
  __ str(implicit_receiver,
         MemOperand(fp, FastConstructFrameConstants::kImplicitReceiverOffset));
 
  // Restore context.
  __ ldr(cp, MemOperand(fp, FastConstructFrameConstants::kContextOffset));
}
 
}  // namespace
 
// static
void Builtins::Generate_InterpreterPushArgsThenFastConstructFunction(
    MacroAssembler* masm) {
  // ----------- S t a t e -------------
  // -- r0 : argument count
  // -- r1 : constructor to call (checked to be a JSFunction)
  // -- r3 : new target
  // -- r4 : address of the first argument
  // -- cp/r7 : context pointer
  // -----------------------------------
  __ AssertFunction(r1);
 
  // Check if target has a [[Construct]] internal method.
  Label non_constructor;
  __ LoadMap(r2, r1);
  __ ldrb(r2, FieldMemOperand(r2, Map::kBitFieldOffset));
  __ tst(r2, Operand(Map::Bits1::IsConstructorBit::kMask));
  __ b(eq, &non_constructor);
 
  // Add a stack check before pushing arguments.
  Label stack_overflow;
  __ StackOverflowCheck(r0, r2, &stack_overflow);
 
  // Enter a construct frame.
  FrameScope scope(masm, StackFrame::MANUAL);
  __ EnterFrame(StackFrame::FAST_CONSTRUCT);
  // Implicit receiver stored in the construct frame.
  __ LoadRoot(r2, RootIndex::kTheHoleValue);
  __ Push(cp, r2);
 
  // Push arguments + implicit receiver.
  Register argc_without_receiver = r6;
  __ sub(argc_without_receiver, r0, Operand(kJSArgcReceiverSlots));
  // Push the arguments. r4 and r5 will be modified.
  GenerateInterpreterPushArgs(masm, argc_without_receiver, r4, r5);
  // Implicit receiver as part of the arguments (patched later if needed).
  __ push(r2);
 
  // Check if it is a builtin call.
  Label builtin_call;
  __ ldr(r2, FieldMemOperand(r1, JSFunction::kSharedFunctionInfoOffset));
  __ ldr(r2, FieldMemOperand(r2, SharedFunctionInfo::kFlagsOffset));
  __ tst(r2, Operand(SharedFunctionInfo::ConstructAsBuiltinBit::kMask));
  __ b(ne, &builtin_call);
 
  // Check if we need to create an implicit receiver.
  Label not_create_implicit_receiver;
  __ DecodeField<SharedFunctionInfo::FunctionKindBits>(r2);
  __ JumpIfIsInRange(
      r2, r2, 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(r1, r3, r0, InvokeType::kCall);
 
  // ----------- S t a t e -------------
  //  -- r0     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(r0, 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);
  __ ldr(r0,
         MemOperand(fp, FastConstructFrameConstants::kImplicitReceiverOffset));
  __ JumpIfRoot(r0, RootIndex::kTheHoleValue, &do_throw);
 
  __ bind(&leave_and_return);
  // Leave construct frame.
  __ LeaveFrame(StackFrame::CONSTRUCT);
  __ Jump(lr);
 
  __ bind(&check_receiver);
  // If the result is a smi, it is *not* an object in the ECMA sense.
  __ JumpIfSmi(r0, &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.
  static_assert(LAST_JS_RECEIVER_TYPE == LAST_TYPE);
  __ CompareObjectType(r0, r4, r5, FIRST_JS_RECEIVER_TYPE);
  __ b(ge, &leave_and_return);
  __ b(&use_receiver);
 
  __ bind(&builtin_call);
  // TODO(victorgomes): Check the possibility to turn this into a tailcall.
  __ InvokeFunctionWithNewTarget(r1, r3, r0, InvokeType::kCall);
  __ LeaveFrame(StackFrame::FAST_CONSTRUCT);
  __ Jump(lr);
 
  __ bind(&do_throw);
  // Restore the context from the frame.
  __ ldr(cp, MemOperand(fp, FastConstructFrameConstants::kContextOffset));
  __ CallRuntime(Runtime::kThrowConstructorReturnedNonObject);
  __ bkpt(0);
 
  __ bind(&stack_overflow);
  // Restore the context from the frame.
  __ TailCallRuntime(Runtime::kThrowStackOverflow);
  // Unreachable code.
  __ bkpt(0);
 
  // 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.
  __ ldr(r2, MemOperand(fp, StandardFrameConstants::kFunctionOffset));
  __ ldr(r2, FieldMemOperand(r2, JSFunction::kSharedFunctionInfoOffset));
  __ ldr(r2,
         FieldMemOperand(r2, SharedFunctionInfo::kTrustedFunctionDataOffset));
  __ CompareObjectType(r2, kInterpreterDispatchTableRegister,
                       kInterpreterDispatchTableRegister,
                       INTERPRETER_DATA_TYPE);
  __ b(ne, &builtin_trampoline);
 
  __ ldr(r2,
         FieldMemOperand(r2, InterpreterData::kInterpreterTrampolineOffset));
  __ LoadCodeInstructionStart(r2, r2);
  __ b(&trampoline_loaded);
 
  __ bind(&builtin_trampoline);
  __ Move(r2, ExternalReference::
                  address_of_interpreter_entry_trampoline_instruction_start(
                      masm->isolate()));
  __ ldr(r2, MemOperand(r2));
 
  __ bind(&trampoline_loaded);
  __ add(lr, r2, Operand(interpreter_entry_return_pc_offset.value()));
 
  // Initialize the dispatch table register.
  __ Move(
      kInterpreterDispatchTableRegister,
      ExternalReference::interpreter_dispatch_table_address(masm->isolate()));
 
  // Get the bytecode array pointer from the frame.
  __ ldr(kInterpreterBytecodeArrayRegister,
         MemOperand(fp, InterpreterFrameConstants::kBytecodeArrayFromFp));
 
  if (v8_flags.debug_code) {
    // Check function data field is actually a BytecodeArray object.
    __ SmiTst(kInterpreterBytecodeArrayRegister);
    __ Assert(
        ne, AbortReason::kFunctionDataShouldBeBytecodeArrayOnInterpreterEntry);
    __ CompareObjectType(kInterpreterBytecodeArrayRegister, r1, no_reg,
                         BYTECODE_ARRAY_TYPE);
    __ Assert(
        eq, AbortReason::kFunctionDataShouldBeBytecodeArrayOnInterpreterEntry);
  }
 
  // Get the target bytecode offset from the frame.
  __ ldr(kInterpreterBytecodeOffsetRegister,
         MemOperand(fp, InterpreterFrameConstants::kBytecodeOffsetFromFp));
  __ SmiUntag(kInterpreterBytecodeOffsetRegister);
 
  if (v8_flags.debug_code) {
    Label okay;
    __ cmp(kInterpreterBytecodeOffsetRegister,
           Operand(BytecodeArray::kHeaderSize - kHeapObjectTag));
    __ b(ge, &okay);
    __ bkpt(0);
    __ bind(&okay);
  }
 
  // Dispatch to the target bytecode.
  UseScratchRegisterScope temps(masm);
  Register scratch = temps.Acquire();
  __ ldrb(scratch, MemOperand(kInterpreterBytecodeArrayRegister,
                              kInterpreterBytecodeOffsetRegister));
  __ ldr(kJavaScriptCallCodeStartRegister,
         MemOperand(kInterpreterDispatchTableRegister, scratch, LSL,
                    kPointerSizeLog2));
  __ Jump(kJavaScriptCallCodeStartRegister);
}
 
void Builtins::Generate_InterpreterEnterAtNextBytecode(MacroAssembler* masm) {
  // Get bytecode array and bytecode offset from the stack frame.
  __ ldr(kInterpreterBytecodeArrayRegister,
         MemOperand(fp, InterpreterFrameConstants::kBytecodeArrayFromFp));
  __ ldr(kInterpreterBytecodeOffsetRegister,
         MemOperand(fp, InterpreterFrameConstants::kBytecodeOffsetFromFp));
  __ SmiUntag(kInterpreterBytecodeOffsetRegister);
 
  Label enter_bytecode, function_entry_bytecode;
  __ cmp(kInterpreterBytecodeOffsetRegister,
         Operand(BytecodeArray::kHeaderSize - kHeapObjectTag +
                 kFunctionEntryBytecodeOffset));
  __ b(eq, &function_entry_bytecode);
 
  // Load the current bytecode.
  __ ldrb(r1, MemOperand(kInterpreterBytecodeArrayRegister,
                         kInterpreterBytecodeOffsetRegister));
 
  // Advance to the next bytecode.
  Label if_return;
  AdvanceBytecodeOffsetOrReturn(masm, kInterpreterBytecodeArrayRegister,
                                kInterpreterBytecodeOffsetRegister, r1, r2, r3,
                                &if_return);
 
  __ bind(&enter_bytecode);
  // Convert new bytecode offset to a Smi and save in the stackframe.
  __ SmiTag(r2, kInterpreterBytecodeOffsetRegister);
  __ str(r2, 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.
  __ mov(kInterpreterBytecodeOffsetRegister,
         Operand(BytecodeArray::kHeaderSize - kHeapObjectTag));
  __ b(&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 temps(masm);
  Register scratch = temps.Acquire();  // Temp register is not allocatable.
  if (with_result) {
    if (javascript_builtin) {
      __ mov(scratch, r0);
    } else {
      // Overwrite the hole inserted by the deoptimizer with the return value
      // from the LAZY deopt point.
      __ str(
          r0,
          MemOperand(
              sp, config->num_allocatable_general_registers() * kPointerSize +
                      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 (javascript_builtin && with_result) {
    // Overwrite the hole inserted by the deoptimizer with the return value from
    // the LAZY deopt point. r0 contains the arguments count, the return value
    // from LAZY is always the last argument.
    constexpr int return_value_offset =
        BuiltinContinuationFrameConstants::kFixedSlotCount -
        kJSArgcReceiverSlots;
    __ add(r0, r0, Operand(return_value_offset));
    __ str(scratch, MemOperand(sp, r0, LSL, kPointerSizeLog2));
    // Recover arguments count.
    __ sub(r0, r0, Operand(return_value_offset));
  }
  __ ldr(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.
  Register builtin = scratch;
  __ Pop(builtin);
  __ add(sp, sp,
         Operand(BuiltinContinuationFrameConstants::kFixedFrameSizeFromFp));
  __ Pop(lr);
  __ LoadEntryFromBuiltinIndex(builtin, builtin);
  __ bx(builtin);
}
}  // 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) {
  {
    FrameAndConstantPoolScope scope(masm, StackFrame::INTERNAL);
    __ CallRuntime(Runtime::kNotifyDeoptimized);
  }
 
  DCHECK_EQ(kInterpreterAccumulatorRegister.code(), r0.code());
  __ pop(r0);
  __ Ret();
}
 
namespace {
 
void Generate_OSREntry(MacroAssembler* masm, Register entry_address,
                       Operand offset = Operand::Zero()) {
  // Compute the target address = entry_address + offset
  if (offset.IsImmediate() && offset.immediate() == 0) {
    __ mov(lr, entry_address);
  } else {
    __ add(lr, entry_address, offset);
  }
 
  // "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).
    __ cmp(maybe_target_code, Operand(Smi::zero()));
    __ b(ne, &jump_to_optimized_code);
  }
 
  ASM_CODE_COMMENT(masm);
  {
    FrameAndConstantPoolScope scope(masm, StackFrame::INTERNAL);
    __ CallRuntime(Runtime::kCompileOptimizedOSR);
  }
 
  // If the code object is null, just return to the caller.
  __ cmp(r0, Operand(Smi::zero()));
  __ b(ne, &jump_to_optimized_code);
  __ Ret();
 
  __ bind(&jump_to_optimized_code);
  DCHECK_EQ(maybe_target_code, r0);  // Already in the right spot.
 
  // OSR entry tracing.
  {
    Label next;
    __ Move(r1, ExternalReference::address_of_log_or_trace_osr());
    __ ldrsb(r1, MemOperand(r1));
    __ tst(r1, Operand(0xFF));  // Mask to the LSB.
    __ b(eq, &next);
 
    {
      FrameAndConstantPoolScope scope(masm, StackFrame::INTERNAL);
      __ Push(r0);  // Preserve the code object.
      __ CallRuntime(Runtime::kLogOrTraceOptimizedOSREntry, 0);
      __ Pop(r0);
    }
 
    __ 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);
  }
 
  // The sandbox would rely on testing expected_parameter_count here.
  static_assert(!V8_ENABLE_SANDBOX_BOOL);
 
  // Load deoptimization data from the code object.
  // <deopt_data> = <code>[#deoptimization_data_offset]
  __ ldr(r1,
         FieldMemOperand(r0, Code::kDeoptimizationDataOrInterpreterDataOffset));
 
  __ LoadCodeInstructionStart(r0, r0);
 
  {
    ConstantPoolUnavailableScope constant_pool_unavailable(masm);
 
    // Load the OSR entrypoint offset from the deoptimization data.
    // <osr_offset> = <deopt_data>[#header_size + #osr_pc_offset]
    __ ldr(r1, FieldMemOperand(r1, FixedArray::OffsetOfElementAt(
                                       DeoptimizationData::kOsrPcOffsetIndex)));
 
    Generate_OSREntry(masm, r0, Operand::SmiUntag(r1));
  }
}
}  // 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);
 
  __ ldr(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 (r0): Stack size (Smi).
  // This builtin can be invoked just after Maglev's prologue.
  // All registers are available, except (possibly) new.target.
  ASM_CODE_COMMENT(masm);
  {
    FrameScope scope(masm, StackFrame::INTERNAL);
    __ AssertSmi(r0);
    if (save_new_target) {
      __ Push(kJavaScriptCallNewTargetRegister);
    }
    __ Push(r0);
    __ 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 -------------
  //  -- r0    : argc
  //  -- sp[0] : receiver
  //  -- sp[4] : thisArg
  //  -- sp[8] : argArray
  // -----------------------------------
 
  // 1. Load receiver into r1, argArray into r2 (if present), remove all
  // arguments from the stack (including the receiver), and push thisArg (if
  // present) instead.
  {
    __ LoadRoot(r5, RootIndex::kUndefinedValue);
    __ mov(r2, r5);
    __ ldr(r1, MemOperand(sp, 0));  // receiver
    __ cmp(r0, Operand(JSParameterCount(1)));
    __ ldr(r5, MemOperand(sp, kSystemPointerSize), ge);  // thisArg
    __ cmp(r0, Operand(JSParameterCount(2)), ge);
    __ ldr(r2, MemOperand(sp, 2 * kSystemPointerSize), ge);  // argArray
    __ DropArgumentsAndPushNewReceiver(r0, r5);
  }
 
  // ----------- S t a t e -------------
  //  -- r2    : argArray
  //  -- r1    : receiver
  //  -- 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;
  __ JumpIfRoot(r2, RootIndex::kNullValue, &no_arguments);
  __ JumpIfRoot(r2, RootIndex::kUndefinedValue, &no_arguments);
 
  // 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);
  {
    __ mov(r0, Operand(JSParameterCount(0)));
    __ TailCallBuiltin(Builtins::Call());
  }
}
 
// static
void Builtins::Generate_FunctionPrototypeCall(MacroAssembler* masm) {
  // 1. Get the callable to call (passed as receiver) from the stack.
  __ Pop(r1);
 
  // 2. Make sure we have at least one argument.
  // r0: actual number of arguments
  {
    Label done;
    __ cmp(r0, Operand(JSParameterCount(0)));
    __ b(ne, &done);
    __ PushRoot(RootIndex::kUndefinedValue);
    __ add(r0, r0, Operand(1));
    __ bind(&done);
  }
 
  // 3. Adjust the actual number of arguments.
  __ sub(r0, r0, Operand(1));
 
  // 4. Call the callable.
  __ TailCallBuiltin(Builtins::Call());
}
 
void Builtins::Generate_ReflectApply(MacroAssembler* masm) {
  // ----------- S t a t e -------------
  //  -- r0     : argc
  //  -- sp[0]  : receiver
  //  -- sp[4]  : target         (if argc >= 1)
  //  -- sp[8]  : thisArgument   (if argc >= 2)
  //  -- sp[12] : argumentsList  (if argc == 3)
  // -----------------------------------
 
  // 1. Load target into r1 (if present), argumentsList into r2 (if present),
  // remove all arguments from the stack (including the receiver), and push
  // thisArgument (if present) instead.
  {
    __ LoadRoot(r1, RootIndex::kUndefinedValue);
    __ mov(r5, r1);
    __ mov(r2, r1);
    __ cmp(r0, Operand(JSParameterCount(1)));
    __ ldr(r1, MemOperand(sp, kSystemPointerSize), ge);  // target
    __ cmp(r0, Operand(JSParameterCount(2)), ge);
    __ ldr(r5, MemOperand(sp, 2 * kSystemPointerSize), ge);  // thisArgument
    __ cmp(r0, Operand(JSParameterCount(3)), ge);
    __ ldr(r2, MemOperand(sp, 3 * kSystemPointerSize), ge);  // argumentsList
    __ DropArgumentsAndPushNewReceiver(r0, r5);
  }
 
  // ----------- S t a t e -------------
  //  -- r2    : argumentsList
  //  -- r1    : target
  //  -- 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 -------------
  //  -- r0     : argc
  //  -- sp[0]  : receiver
  //  -- sp[4]  : target
  //  -- sp[8]  : argumentsList
  //  -- sp[12] : new.target (optional)
  // -----------------------------------
 
  // 1. Load target into r1 (if present), argumentsList into r2 (if present),
  // new.target into r3 (if present, otherwise use target), remove all
  // arguments from the stack (including the receiver), and push thisArgument
  // (if present) instead.
  {
    __ LoadRoot(r1, RootIndex::kUndefinedValue);
    __ mov(r2, r1);
    __ mov(r4, r1);
    __ cmp(r0, Operand(JSParameterCount(1)));
    __ ldr(r1, MemOperand(sp, kSystemPointerSize), ge);  // target
    __ mov(r3, r1);  // new.target defaults to target
    __ cmp(r0, Operand(JSParameterCount(2)), ge);
    __ ldr(r2, MemOperand(sp, 2 * kSystemPointerSize), ge);  // argumentsList
    __ cmp(r0, Operand(JSParameterCount(3)), ge);
    __ ldr(r3, MemOperand(sp, 3 * kSystemPointerSize), ge);  // new.target
    __ DropArgumentsAndPushNewReceiver(r0, r4);
  }
 
  // ----------- S t a t e -------------
  //  -- r2    : argumentsList
  //  -- r3    : new.target
  //  -- r1    : 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, Register scratch1, Register scratch2) {
  DCHECK(!AreAliased(count, argc_in_out, pointer_to_new_space_out, scratch1,
                     scratch2));
  UseScratchRegisterScope temps(masm);
  Register old_sp = scratch1;
  Register new_space = scratch2;
  __ mov(old_sp, sp);
  __ lsl(new_space, count, Operand(kSystemPointerSizeLog2));
  __ AllocateStackSpace(new_space);
 
  Register end = scratch2;
  Register value = temps.Acquire();
  Register dest = pointer_to_new_space_out;
  __ mov(dest, sp);
  __ add(end, old_sp, Operand(argc_in_out, LSL, kSystemPointerSizeLog2));
  Label loop, done;
  __ bind(&loop);
  __ cmp(old_sp, end);
  __ b(ge, &done);
  __ ldr(value, MemOperand(old_sp, kSystemPointerSize, PostIndex));
  __ str(value, MemOperand(dest, kSystemPointerSize, PostIndex));
  __ b(&loop);
  __ bind(&done);
 
  // Update total number of arguments.
  __ add(argc_in_out, argc_in_out, count);
}
 
}  // namespace
 
// static
// TODO(v8:11615): Observe Code::kMaxArguments in
// CallOrConstructVarargs
void Builtins::Generate_CallOrConstructVarargs(MacroAssembler* masm,
                                               Builtin target_builtin) {
  // ----------- S t a t e -------------
  //  -- r1 : target
  //  -- r0 : number of parameters on the stack
  //  -- r2 : arguments list (a FixedArray)
  //  -- r4 : len (number of elements to push from args)
  //  -- r3 : new.target (for [[Construct]])
  // -----------------------------------
  Register scratch = r8;
 
  if (v8_flags.debug_code) {
    // Allow r2 to be a FixedArray, or a FixedDoubleArray if r4 == 0.
    Label ok, fail;
    __ AssertNotSmi(r2);
    __ ldr(scratch, FieldMemOperand(r2, HeapObject::kMapOffset));
    __ ldrh(r6, FieldMemOperand(scratch, Map::kInstanceTypeOffset));
    __ cmp(r6, Operand(FIXED_ARRAY_TYPE));
    __ b(eq, &ok);
    __ cmp(r6, Operand(FIXED_DOUBLE_ARRAY_TYPE));
    __ b(ne, &fail);
    __ cmp(r4, Operand(0));
    __ b(eq, &ok);
    // Fall through.
    __ bind(&fail);
    __ Abort(AbortReason::kOperandIsNotAFixedArray);
 
    __ bind(&ok);
  }
 
  Label stack_overflow;
  __ StackOverflowCheck(r4, scratch, &stack_overflow);
 
  // Move the arguments already in the stack,
  // including the receiver and the return address.
  // r4: Number of arguments to make room for.
  // r0: Number of arguments already on the stack.
  // r9: Points to first free slot on the stack after arguments were shifted.
  Generate_AllocateSpaceAndShiftExistingArguments(masm, r4, r0, r9, r5, r6);
 
  // Copy arguments onto the stack (thisArgument is already on the stack).
  {
    __ mov(r6, Operand(0));
    __ LoadRoot(r5, RootIndex::kTheHoleValue);
    Label done, loop;
    __ bind(&loop);
    __ cmp(r6, r4);
    __ b(eq, &done);
    __ add(scratch, r2, Operand(r6, LSL, kTaggedSizeLog2));
    __ ldr(scratch, FieldMemOperand(scratch, OFFSET_OF_DATA_START(FixedArray)));
    __ cmp(scratch, r5);
    // Turn the hole into undefined as we go.
    __ LoadRoot(scratch, RootIndex::kUndefinedValue, eq);
    __ str(scratch, MemOperand(r9, kSystemPointerSize, PostIndex));
    __ add(r6, r6, Operand(1));
    __ b(&loop);
    __ 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 -------------
  //  -- r0 : the number of arguments
  //  -- r3 : the new.target (for [[Construct]] calls)
  //  -- r1 : the target to call (can be any Object)
  //  -- r2 : start index (to support rest parameters)
  // -----------------------------------
 
  Register scratch = r6;
 
  // Check if new.target has a [[Construct]] internal method.
  if (mode == CallOrConstructMode::kConstruct) {
    Label new_target_constructor, new_target_not_constructor;
    __ JumpIfSmi(r3, &new_target_not_constructor);
    __ ldr(scratch, FieldMemOperand(r3, HeapObject::kMapOffset));
    __ ldrb(scratch, FieldMemOperand(scratch, Map::kBitFieldOffset));
    __ tst(scratch, Operand(Map::Bits1::IsConstructorBit::kMask));
    __ b(ne, &new_target_constructor);
    __ bind(&new_target_not_constructor);
    {
      FrameScope scope(masm, StackFrame::MANUAL);
      __ EnterFrame(StackFrame::INTERNAL);
      __ Push(r3);
      __ CallRuntime(Runtime::kThrowNotConstructor);
    }
    __ bind(&new_target_constructor);
  }
 
  Label stack_done, stack_overflow;
  __ ldr(r5, MemOperand(fp, StandardFrameConstants::kArgCOffset));
  __ sub(r5, r5, Operand(kJSArgcReceiverSlots));
  __ sub(r5, r5, r2, SetCC);
  __ b(le, &stack_done);
  {
    // ----------- S t a t e -------------
    //  -- r0 : the number of arguments already in the stack
    //  -- r1 : the target to call (can be any Object)
    //  -- r2 : start index (to support rest parameters)
    //  -- r3 : the new.target (for [[Construct]] calls)
    //  -- fp : point to the caller stack frame
    //  -- r5 : number of arguments to copy, i.e. arguments count - start index
    // -----------------------------------
 
    // Check for stack overflow.
    __ StackOverflowCheck(r5, scratch, &stack_overflow);
 
    // Forward the arguments from the caller frame.
    // Point to the first argument to copy (skipping the receiver).
    __ add(r4, fp,
           Operand(CommonFrameConstants::kFixedFrameSizeAboveFp +
                   kSystemPointerSize));
    __ add(r4, r4, Operand(r2, LSL, kSystemPointerSizeLog2));
 
    // Move the arguments already in the stack,
    // including the receiver and the return address.
    // r5: Number of arguments to make room for.
    // r0: Number of arguments already on the stack.
    // r2: Points to first free slot on the stack after arguments were shifted.
    Generate_AllocateSpaceAndShiftExistingArguments(masm, r5, r0, r2, scratch,
                                                    r8);
 
    // Copy arguments from the caller frame.
    // TODO(victorgomes): Consider using forward order as potentially more cache
    // friendly.
    {
      Label loop;
      __ bind(&loop);
      {
        __ sub(r5, r5, Operand(1), SetCC);
        __ ldr(scratch, MemOperand(r4, r5, LSL, kSystemPointerSizeLog2));
        __ str(scratch, MemOperand(r2, r5, LSL, kSystemPointerSizeLog2));
        __ b(ne, &loop);
      }
    }
  }
  __ 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 -------------
  //  -- r0 : the number of arguments
  //  -- r1 : the function to call (checked to be a JSFunction)
  // -----------------------------------
  __ AssertCallableFunction(r1);
 
  __ ldr(r2, FieldMemOperand(r1, 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.
  __ ldr(cp, FieldMemOperand(r1, JSFunction::kContextOffset));
  // We need to convert the receiver for non-native sloppy mode functions.
  Label done_convert;
  __ ldr(r3, FieldMemOperand(r2, SharedFunctionInfo::kFlagsOffset));
  __ tst(r3, Operand(SharedFunctionInfo::IsNativeBit::kMask |
                     SharedFunctionInfo::IsStrictBit::kMask));
  __ b(ne, &done_convert);
  {
    // ----------- S t a t e -------------
    //  -- r0 : the number of arguments
    //  -- r1 : the function to call (checked to be a JSFunction)
    //  -- r2 : the shared function info.
    //  -- cp : the function context.
    // -----------------------------------
 
    if (mode == ConvertReceiverMode::kNullOrUndefined) {
      // Patch receiver to global proxy.
      __ LoadGlobalProxy(r3);
    } else {
      Label convert_to_object, convert_receiver;
      __ ldr(r3, __ ReceiverOperand());
      __ JumpIfSmi(r3, &convert_to_object);
      static_assert(LAST_JS_RECEIVER_TYPE == LAST_TYPE);
      __ CompareObjectType(r3, r4, r4, FIRST_JS_RECEIVER_TYPE);
      __ b(hs, &done_convert);
      if (mode != ConvertReceiverMode::kNotNullOrUndefined) {
        Label convert_global_proxy;
        __ JumpIfRoot(r3, RootIndex::kUndefinedValue, &convert_global_proxy);
        __ JumpIfNotRoot(r3, RootIndex::kNullValue, &convert_to_object);
        __ bind(&convert_global_proxy);
        {
          // Patch receiver to global proxy.
          __ LoadGlobalProxy(r3);
        }
        __ b(&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?)
        FrameAndConstantPoolScope scope(masm, StackFrame::INTERNAL);
        __ SmiTag(r0);
        __ Push(r0, r1);
        __ mov(r0, r3);
        __ Push(cp);
        __ CallBuiltin(Builtin::kToObject);
        __ Pop(cp);
        __ mov(r3, r0);
        __ Pop(r0, r1);
        __ SmiUntag(r0);
      }
      __ ldr(r2, FieldMemOperand(r1, JSFunction::kSharedFunctionInfoOffset));
      __ bind(&convert_receiver);
    }
    __ str(r3, __ ReceiverOperand());
  }
  __ bind(&done_convert);
 
  // ----------- S t a t e -------------
  //  -- r0 : the number of arguments
  //  -- r1 : the function to call (checked to be a JSFunction)
  //  -- r2 : the shared function info.
  //  -- cp : the function context.
  // -----------------------------------
 
  __ ldrh(r2,
          FieldMemOperand(r2, SharedFunctionInfo::kFormalParameterCountOffset));
  __ InvokeFunctionCode(r1, no_reg, r2, r0, InvokeType::kJump);
}
 
namespace {
 
void Generate_PushBoundArguments(MacroAssembler* masm) {
  ASM_CODE_COMMENT(masm);
  // ----------- S t a t e -------------
  //  -- r0 : the number of arguments
  //  -- r1 : target (checked to be a JSBoundFunction)
  //  -- r3 : new.target (only in case of [[Construct]])
  // -----------------------------------
 
  // Load [[BoundArguments]] into r2 and length of that into r4.
  Label no_bound_arguments;
  __ ldr(r2, FieldMemOperand(r1, JSBoundFunction::kBoundArgumentsOffset));
  __ ldr(r4, FieldMemOperand(r2, offsetof(FixedArray, length_)));
  __ SmiUntag(r4);
  __ cmp(r4, Operand(0));
  __ b(eq, &no_bound_arguments);
  {
    // ----------- S t a t e -------------
    //  -- r0 : the number of arguments
    //  -- r1 : target (checked to be a JSBoundFunction)
    //  -- r2 : the [[BoundArguments]] (implemented as FixedArray)
    //  -- r3 : new.target (only in case of [[Construct]])
    //  -- r4 : the number of [[BoundArguments]]
    // -----------------------------------
 
    Register scratch = r6;
 
    {
      // 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 done;
      __ mov(scratch, Operand(r4, LSL, kSystemPointerSizeLog2));
      {
        UseScratchRegisterScope temps(masm);
        Register remaining_stack_size = temps.Acquire();
        DCHECK(!AreAliased(r0, r1, r2, r3, r4, scratch, remaining_stack_size));
 
        // Compute the space we have left. The stack might already be overflowed
        // here which will cause remaining_stack_size to become negative.
        __ LoadStackLimit(remaining_stack_size,
                          StackLimitKind::kRealStackLimit);
        __ sub(remaining_stack_size, sp, remaining_stack_size);
 
        // Check if the arguments will overflow the stack.
        __ cmp(remaining_stack_size, scratch);
      }
      __ b(gt, &done);
      {
        FrameScope scope(masm, StackFrame::MANUAL);
        __ EnterFrame(StackFrame::INTERNAL);
        __ CallRuntime(Runtime::kThrowStackOverflow);
      }
      __ bind(&done);
    }
 
    // Pop receiver.
    __ Pop(r5);
 
    // Push [[BoundArguments]].
    {
      Label loop;
      __ add(r0, r0, r4);  // Adjust effective number of arguments.
      __ add(r2, r2,
             Operand(OFFSET_OF_DATA_START(FixedArray) - kHeapObjectTag));
      __ bind(&loop);
      __ sub(r4, r4, Operand(1), SetCC);
      __ ldr(scratch, MemOperand(r2, r4, LSL, kTaggedSizeLog2));
      __ Push(scratch);
      __ b(gt, &loop);
    }
 
    // Push receiver.
    __ Push(r5);
  }
  __ bind(&no_bound_arguments);
}
 
}  // namespace
 
// static
void Builtins::Generate_CallBoundFunctionImpl(MacroAssembler* masm) {
  // ----------- S t a t e -------------
  //  -- r0 : the number of arguments
  //  -- r1 : the function to call (checked to be a JSBoundFunction)
  // -----------------------------------
  __ AssertBoundFunction(r1);
 
  // Patch the receiver to [[BoundThis]].
  __ ldr(r3, FieldMemOperand(r1, JSBoundFunction::kBoundThisOffset));
  __ str(r3, __ ReceiverOperand());
 
  // Push the [[BoundArguments]] onto the stack.
  Generate_PushBoundArguments(masm);
 
  // Call the [[BoundTargetFunction]] via the Call builtin.
  __ ldr(r1, FieldMemOperand(r1, JSBoundFunction::kBoundTargetFunctionOffset));
  __ TailCallBuiltin(Builtins::Call());
}
 
// static
void Builtins::Generate_Call(MacroAssembler* masm, ConvertReceiverMode mode) {
  // ----------- S t a t e -------------
  //  -- r0 : the number of arguments
  //  -- r1 : the target to call (can be any Object).
  // -----------------------------------
  Register target = r1;
  Register map = r4;
  Register instance_type = r5;
  Register scratch = r6;
  DCHECK(!AreAliased(r0, target, map, instance_type));
 
  Label non_callable, class_constructor;
  __ JumpIfSmi(target, &non_callable);
  __ LoadMap(map, target);
  __ CompareInstanceTypeRange(map, instance_type, scratch,
                              FIRST_CALLABLE_JS_FUNCTION_TYPE,
                              LAST_CALLABLE_JS_FUNCTION_TYPE);
  __ TailCallBuiltin(Builtins::CallFunction(mode), ls);
  __ cmp(instance_type, Operand(JS_BOUND_FUNCTION_TYPE));
  __ TailCallBuiltin(Builtin::kCallBoundFunction, eq);
 
  // Check if target has a [[Call]] internal method.
  {
    Register flags = r4;
    __ ldrb(flags, FieldMemOperand(map, Map::kBitFieldOffset));
    map = no_reg;
    __ tst(flags, Operand(Map::Bits1::IsCallableBit::kMask));
    __ b(eq, &non_callable);
  }
 
  // Check if target is a proxy and call CallProxy external builtin
  __ cmp(instance_type, Operand(JS_PROXY_TYPE));
  __ TailCallBuiltin(Builtin::kCallProxy, eq);
 
  // Check if target is a wrapped function and call CallWrappedFunction external
  // builtin
  __ cmp(instance_type, Operand(JS_WRAPPED_FUNCTION_TYPE));
  __ TailCallBuiltin(Builtin::kCallWrappedFunction, eq);
 
  // ES6 section 9.2.1 [[Call]] ( thisArgument, argumentsList)
  // Check that the function is not a "classConstructor".
  __ cmp(instance_type, Operand(JS_CLASS_CONSTRUCTOR_TYPE));
  __ b(eq, &class_constructor);
 
  // 2. Call to something else, which might have a [[Call]] internal method (if
  // not we raise an exception).
  // Overwrite the original receiver the (original) target.
  __ str(target, __ ReceiverOperand());
  // 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);
  {
    FrameAndConstantPoolScope scope(masm, StackFrame::INTERNAL);
    __ Push(target);
    __ CallRuntime(Runtime::kThrowCalledNonCallable);
    __ Trap();  // Unreachable.
  }
 
  // 4. The function is a "classConstructor", need to raise an exception.
  __ bind(&class_constructor);
  {
    FrameAndConstantPoolScope scope(masm, StackFrame::INTERNAL);
    __ Push(target);
    __ CallRuntime(Runtime::kThrowConstructorNonCallableError);
    __ Trap();  // Unreachable.
  }
}
 
// static
void Builtins::Generate_ConstructFunction(MacroAssembler* masm) {
  // ----------- S t a t e -------------
  //  -- r0 : the number of arguments
  //  -- r1 : the constructor to call (checked to be a JSFunction)
  //  -- r3 : the new target (checked to be a constructor)
  // -----------------------------------
  __ AssertConstructor(r1);
  __ AssertFunction(r1);
 
  // Calling convention for function specific ConstructStubs require
  // r2 to contain either an AllocationSite or undefined.
  __ LoadRoot(r2, RootIndex::kUndefinedValue);
 
  Label call_generic_stub;
 
  // Jump to JSBuiltinsConstructStub or JSConstructStubGeneric.
  __ ldr(r4, FieldMemOperand(r1, JSFunction::kSharedFunctionInfoOffset));
  __ ldr(r4, FieldMemOperand(r4, SharedFunctionInfo::kFlagsOffset));
  __ tst(r4, Operand(SharedFunctionInfo::ConstructAsBuiltinBit::kMask));
  __ b(eq, &call_generic_stub);
 
  __ TailCallBuiltin(Builtin::kJSBuiltinsConstructStub);
 
  __ bind(&call_generic_stub);
  __ TailCallBuiltin(Builtin::kJSConstructStubGeneric);
}
 
// static
void Builtins::Generate_ConstructBoundFunction(MacroAssembler* masm) {
  // ----------- S t a t e -------------
  //  -- r0 : the number of arguments
  //  -- r1 : the function to call (checked to be a JSBoundFunction)
  //  -- r3 : the new target (checked to be a constructor)
  // -----------------------------------
  __ AssertConstructor(r1);
  __ AssertBoundFunction(r1);
 
  // Push the [[BoundArguments]] onto the stack.
  Generate_PushBoundArguments(masm);
 
  // Patch new.target to [[BoundTargetFunction]] if new.target equals target.
  __ cmp(r1, r3);
  __ ldr(r3, FieldMemOperand(r1, JSBoundFunction::kBoundTargetFunctionOffset),
         eq);
 
  // Construct the [[BoundTargetFunction]] via the Construct builtin.
  __ ldr(r1, FieldMemOperand(r1, JSBoundFunction::kBoundTargetFunctionOffset));
  __ TailCallBuiltin(Builtin::kConstruct);
}
 
// static
void Builtins::Generate_Construct(MacroAssembler* masm) {
  // ----------- S t a t e -------------
  //  -- r0 : the number of arguments
  //  -- r1 : the constructor to call (can be any Object)
  //  -- r3 : the new target (either the same as the constructor or
  //          the JSFunction on which new was invoked initially)
  // -----------------------------------
  Register target = r1;
  Register map = r4;
  Register instance_type = r5;
  Register scratch = r6;
  DCHECK(!AreAliased(r0, 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.
  __ ldr(map, FieldMemOperand(target, HeapObject::kMapOffset));
  {
    Register flags = r2;
    DCHECK(!AreAliased(r0, target, map, instance_type, flags));
    __ ldrb(flags, FieldMemOperand(map, Map::kBitFieldOffset));
    __ tst(flags, Operand(Map::Bits1::IsConstructorBit::kMask));
    __ b(eq, &non_constructor);
  }
 
  // Dispatch based on instance type.
  __ CompareInstanceTypeRange(map, instance_type, scratch,
                              FIRST_JS_FUNCTION_TYPE, LAST_JS_FUNCTION_TYPE);
  __ TailCallBuiltin(Builtin::kConstructFunction, ls);
 
  // Only dispatch to bound functions after checking whether they are
  // constructors.
  __ cmp(instance_type, Operand(JS_BOUND_FUNCTION_TYPE));
  __ TailCallBuiltin(Builtin::kConstructBoundFunction, eq);
 
  // Only dispatch to proxies after checking whether they are constructors.
  __ cmp(instance_type, Operand(JS_PROXY_TYPE));
  __ b(ne, &non_proxy);
  __ 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.
    __ str(target, __ ReceiverOperand());
    // 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
 
struct SaveWasmParamsScope {
  explicit SaveWasmParamsScope(MacroAssembler* masm)
      : lowest_fp_reg(std::begin(wasm::kFpParamRegisters)[0]),
        highest_fp_reg(std::end(wasm::kFpParamRegisters)[-1]),
        masm(masm) {
    for (Register gp_param_reg : wasm::kGpParamRegisters) {
      gp_regs.set(gp_param_reg);
    }
    gp_regs.set(lr);
    for (DwVfpRegister fp_param_reg : wasm::kFpParamRegisters) {
      CHECK(fp_param_reg.code() >= lowest_fp_reg.code() &&
            fp_param_reg.code() <= highest_fp_reg.code());
    }
 
    CHECK_EQ(gp_regs.Count(), arraysize(wasm::kGpParamRegisters) + 1);
    CHECK_EQ(highest_fp_reg.code() - lowest_fp_reg.code() + 1,
             arraysize(wasm::kFpParamRegisters));
    CHECK_EQ(gp_regs.Count(),
             WasmLiftoffSetupFrameConstants::kNumberOfSavedGpParamRegs +
                 1 /* instance */ + 1 /* lr */);
    CHECK_EQ(highest_fp_reg.code() - lowest_fp_reg.code() + 1,
             WasmLiftoffSetupFrameConstants::kNumberOfSavedFpParamRegs);
 
    __ stm(db_w, sp, gp_regs);
    __ vstm(db_w, sp, lowest_fp_reg, highest_fp_reg);
  }
  ~SaveWasmParamsScope() {
    __ vldm(ia_w, sp, lowest_fp_reg, highest_fp_reg);
    __ ldm(ia_w, sp, gp_regs);
  }
 
  RegList gp_regs;
  DwVfpRegister lowest_fp_reg;
  DwVfpRegister highest_fp_reg;
  MacroAssembler* masm;
};
 
// This builtin creates the following stack frame:
//
// [  feedback vector   ]  <-- sp  // Added by this builtin.
// [ Wasm instance data ]          // Added by this builtin.
// [ WASM frame marker  ]          // Already there on entry.
// [     saved fp       ]  <-- fp  // Already there on entry.
void Builtins::Generate_WasmLiftoffFrameSetup(MacroAssembler* masm) {
  Register func_index = wasm::kLiftoffFrameSetupFunctionReg;
  Register vector = r5;
  Register scratch = r7;
  Label allocate_vector, done;
 
  __ ldr(vector,
         FieldMemOperand(kWasmImplicitArgRegister,
                         WasmTrustedInstanceData::kFeedbackVectorsOffset));
  __ add(vector, vector, Operand(func_index, LSL, kTaggedSizeLog2));
  __ ldr(vector, FieldMemOperand(vector, OFFSET_OF_DATA_START(FixedArray)));
  __ JumpIfSmi(vector, &allocate_vector);
  __ bind(&done);
  __ push(kWasmImplicitArgRegister);
  __ 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.
  __ mov(scratch,
         Operand(StackFrame::TypeToMarker(StackFrame::WASM_LIFTOFF_SETUP)));
  __ str(scratch, MemOperand(sp));
  {
    SaveWasmParamsScope save_params(masm);
    // Arguments to the runtime function: instance data, func_index.
    __ push(kWasmImplicitArgRegister);
    __ SmiTag(func_index);
    __ push(func_index);
    // Allocate a stack slot where the runtime function can spill a pointer
    // to the {NativeModule}.
    __ push(r8);
    __ Move(cp, Smi::zero());
    __ CallRuntime(Runtime::kWasmAllocateFeedbackVector, 3);
    __ mov(vector, kReturnRegister0);
    // Saved parameters are restored at the end of this block.
  }
  __ mov(scratch, Operand(StackFrame::TypeToMarker(StackFrame::WASM)));
  __ str(scratch, MemOperand(sp));
  __ b(&done);
}
 
void Builtins::Generate_WasmCompileLazy(MacroAssembler* masm) {
  // The function index was put in a register by the jump table trampoline.
  // Convert to Smi for the runtime call.
  __ SmiTag(kWasmCompileLazyFuncIndexRegister);
  {
    HardAbortScope hard_abort(masm);  // Avoid calls to Abort.
    FrameAndConstantPoolScope scope(masm, StackFrame::INTERNAL);
 
    {
      SaveWasmParamsScope save_params(masm);
 
      // Push the instance data as an explicit argument to the runtime function.
      __ push(kWasmImplicitArgRegister);
      // Push the function index as second argument.
      __ push(kWasmCompileLazyFuncIndexRegister);
      // Initialize the JavaScript context with 0. CEntry will use it to
      // set the current context on the isolate.
      __ Move(cp, Smi::zero());
      __ CallRuntime(Runtime::kWasmCompileLazy, 2);
      // The runtime function returns the jump table slot offset as a Smi. Use
      // that to compute the jump target in r8.
      __ mov(r8, Operand::SmiUntag(kReturnRegister0));
 
      // Saved parameters are restored at the end of this block.
    }
 
    // After the instance data register has been restored, we can add the jump
    // table start to the jump table offset already stored in r8.
    __ ldr(r9, FieldMemOperand(kWasmImplicitArgRegister,
                               WasmTrustedInstanceData::kJumpTableStartOffset));
    __ add(r8, r8, r9);
  }
 
  // Finally, jump to the jump table slot for the function.
  __ Jump(r8);
}
 
void Builtins::Generate_WasmDebugBreak(MacroAssembler* masm) {
  HardAbortScope hard_abort(masm);  // Avoid calls to Abort.
  {
    FrameAndConstantPoolScope scope(masm, StackFrame::WASM_DEBUG_BREAK);
 
    static_assert(DwVfpRegister::kNumRegisters == 32);
    constexpr DwVfpRegister last =
        WasmDebugBreakFrameConstants::kPushedFpRegs.last();
    constexpr DwVfpRegister first =
        WasmDebugBreakFrameConstants::kPushedFpRegs.first();
    static_assert(
        WasmDebugBreakFrameConstants::kPushedFpRegs.Count() ==
            last.code() - first.code() + 1,
        "All registers in the range from first to last have to be set");
 
    // Save all parameter registers. They might hold live values, we restore
    // them after the runtime call.
    constexpr DwVfpRegister lowest_fp_reg = first;
    constexpr DwVfpRegister highest_fp_reg = last;
 
    // Store gp parameter registers.
    __ stm(db_w, sp, WasmDebugBreakFrameConstants::kPushedGpRegs);
    // Store fp parameter registers.
    __ vstm(db_w, sp, lowest_fp_reg, highest_fp_reg);
 
    // 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.
    __ vldm(ia_w, sp, lowest_fp_reg, highest_fp_reg);
    __ ldm(ia_w, sp, WasmDebugBreakFrameConstants::kPushedGpRegs);
  }
  __ Ret();
}
 
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 stack, Register tmp,
                      wasm::JumpBuffer::StackState old_state,
                      wasm::JumpBuffer::StackState new_state) {
  __ ldr(tmp, MemOperand(stack, wasm::kStackStateOffset));
  Label ok;
  __ JumpIfEqual(tmp, old_state, &ok);
  __ Trap();
  __ bind(&ok);
  __ mov(tmp, Operand(new_state));
  __ str(tmp, MemOperand(stack, wasm::kStackStateOffset));
}
 
// Switch the stack pointer.
void SwitchStackPointer(MacroAssembler* masm, Register stack) {
  __ ldr(sp, MemOperand(stack, wasm::kStackSpOffset));
}
 
void FillJumpBuffer(MacroAssembler* masm, Register stack, Label* target,
                    Register tmp) {
  __ mov(tmp, sp);
  __ str(tmp, MemOperand(stack, wasm::kStackSpOffset));
  __ str(fp, MemOperand(stack, wasm::kStackFpOffset));
  __ LoadStackLimit(tmp, StackLimitKind::kRealStackLimit);
  __ str(tmp, MemOperand(stack, wasm::kStackLimitOffset));
 
  __ GetLabelAddress(tmp, target);
  // Stash the address in the jump buffer.
  __ str(tmp, MemOperand(stack, wasm::kStackPcOffset));
}
 
void LoadJumpBuffer(MacroAssembler* masm, Register stack, bool load_pc,
                    Register tmp, wasm::JumpBuffer::StackState expected_state) {
  SwitchStackPointer(masm, stack);
  __ ldr(fp, MemOperand(stack, wasm::kStackFpOffset));
  SwitchStackState(masm, stack, tmp, expected_state, wasm::JumpBuffer::Active);
  if (load_pc) {
    __ ldr(tmp, MemOperand(stack, wasm::kStackPcOffset));
    __ bx(tmp);
  }
  // The stack limit in StackGuard is set separately under the ExecutionAccess
  // lock.
}
 
void LoadTargetJumpBuffer(MacroAssembler* masm, Register target_stack,
                          Register tmp,
                          wasm::JumpBuffer::StackState expected_state) {
  __ Zero(MemOperand(fp, StackSwitchFrameConstants::kGCScanSlotCountOffset));
  // Switch stack!
  LoadJumpBuffer(masm, target_stack, false, tmp, expected_state);
}
 
// Updates the stack limit and central stack info, and validates the switch.
void SwitchStacks(MacroAssembler* masm, Register old_stack, bool return_switch,
                  const std::initializer_list<Register> keep) {
  using ER = ExternalReference;
 
  for (auto reg : keep) {
    __ Push(reg);
  }
 
  {
    __ PrepareCallCFunction(2);
    FrameScope scope(masm, StackFrame::MANUAL);
    // Move {old_stack} first in case it aliases kCArgRegs[0].
    __ Move(kCArgRegs[1], old_stack);
    __ Move(kCArgRegs[0], ExternalReference::isolate_address(masm->isolate()));
    __ 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 ReloadParentStack(MacroAssembler* masm, Register return_reg,
                       Register return_value, Register context, Register tmp1,
                       Register tmp2, Register tmp3) {
  Register active_stack = tmp1;
  __ LoadRootRelative(active_stack, IsolateData::active_stack_offset());
 
  // Set a null pointer in the jump buffer's SP slot to indicate to the stack
  // frame iterator that this stack is empty.
  __ Zero(MemOperand(active_stack, wasm::kStackSpOffset));
  {
    UseScratchRegisterScope temps(masm);
    Register scratch = temps.Acquire();
    SwitchStackState(masm, active_stack, scratch, wasm::JumpBuffer::Active,
                     wasm::JumpBuffer::Retired);
  }
  Register parent = tmp2;
  __ ldr(parent, MemOperand(active_stack, wasm::kStackParentOffset));
 
  // Update active stack.
  __ StoreRootRelative(IsolateData::active_stack_offset(), parent);
 
  // Switch stack!
  SwitchStacks(masm, active_stack, true,
               {return_reg, return_value, context, parent});
  LoadJumpBuffer(masm, parent, false, tmp3, wasm::JumpBuffer::Inactive);
}
 
void RestoreParentSuspender(MacroAssembler* masm, Register tmp1) {
  Register suspender = tmp1;
  __ LoadRoot(suspender, RootIndex::kActiveSuspender);
  __ LoadTaggedField(
      suspender,
      FieldMemOperand(suspender, WasmSuspenderObject::kParentOffset));
 
  int32_t active_suspender_offset =
      MacroAssembler::RootRegisterOffsetForRootIndex(
          RootIndex::kActiveSuspender);
  __ str(suspender, MemOperand(kRootRegister, active_suspender_offset));
}
 
void ResetStackSwitchFrameStackSlots(MacroAssembler* masm) {
  __ Zero(MemOperand(fp, StackSwitchFrameConstants::kResultArrayOffset),
          MemOperand(fp, StackSwitchFrameConstants::kImplicitArgOffset));
}
 
// TODO(irezvov): Consolidate with arm64 RegisterAllocator.
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) {
    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;
        it = 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 DEFINE_REG_W(Name) \
  DEFINE_REG(Name);        \
  Name = Name.W();
 
#define ASSIGN_REG(Name) regs.Ask(&Name);
 
#define ASSIGN_REG_W(Name) \
  ASSIGN_REG(Name);        \
  Name = Name.W();
 
#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);
 
// 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));
  __ CompareInstanceType(scratch, scratch, WASM_TRUSTED_INSTANCE_DATA_TYPE);
  Label instance;
  Label end;
  __ b(eq, &instance);
  __ LoadTaggedField(
      data, FieldMemOperand(data, WasmImportData::kNativeContextOffset));
  __ jmp(&end);
  __ bind(&instance);
  __ LoadTaggedField(
      data,
      FieldMemOperand(data, WasmTrustedInstanceData::kNativeContextOffset));
  __ bind(&end);
}
 
}  // namespace
 
void Builtins::Generate_WasmToJsWrapperAsm(MacroAssembler* masm) {
  // Push registers in reverse order so that they are on the stack like
  // in an array, with the first item being at the lowest address.
  for (int i = static_cast<int>(arraysize(wasm::kFpParamRegisters)) - 1; i >= 0;
       --i) {
    __ vpush(wasm::kFpParamRegisters[i]);
  }
 
  // r6 is pushed for alignment, so that the pushed register parameters and
  // stack parameters look the same as the layout produced by the js-to-wasm
  // wrapper for out-going parameters. Having the same layout allows to share
  // code in Torque, especially the `LocationAllocator`. r6 has been picked
  // arbitrarily.
  __ Push(r6, wasm::kGpParamRegisters[3], wasm::kGpParamRegisters[2],
          wasm::kGpParamRegisters[1]);
  // Reserve a slot for the signature.
  __ Push(r0);
  __ TailCallBuiltin(Builtin::kWasmToJsWrapperCSA);
}
 
void Builtins::Generate_WasmTrapHandlerLandingPad(MacroAssembler* masm) {
  __ Trap();
}
 
void Builtins::Generate_WasmSuspend(MacroAssembler* masm) {
  auto regs = RegisterAllocator::WithAllocatableGeneralRegisters();
  // Set up the stackframe.
  __ EnterFrame(StackFrame::STACK_SWITCH);
 
  DEFINE_PINNED(suspender, r0);
  DEFINE_PINNED(context, kContextRegister);
 
  __ sub(
      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(stack);
  __ LoadRootRelative(stack, IsolateData::active_stack_offset());
  DEFINE_REG(scratch);
  FillJumpBuffer(masm, stack, &resume, scratch);
  SwitchStackState(masm, stack, scratch, wasm::JumpBuffer::Active,
                   wasm::JumpBuffer::Suspended);
  regs.ResetExcept(suspender, stack);
 
  DEFINE_REG(suspender_stack);
  __ ldr(suspender_stack,
         FieldMemOperand(suspender, WasmSuspenderObject::kStackOffset));
  if (v8_flags.debug_code) {
    // -------------------------------------------
    // Check that the suspender's stack is the active stack.
    // -------------------------------------------
    // TODO(thibaudm): Once we add core stack-switching instructions, this
    // check will not hold anymore: it's possible that the active stack
    // changed (due to an internal switch), so we have to update the suspender.
    __ cmp(suspender_stack, stack);
    Label ok;
    __ b(&ok, eq);
    __ Trap();
    __ bind(&ok);
  }
  // -------------------------------------------
  // Update roots.
  // -------------------------------------------
  DEFINE_REG(caller);
  __ ldr(caller, MemOperand(suspender_stack, wasm::kStackParentOffset));
  __ StoreRootRelative(IsolateData::active_stack_offset(), caller);
  DEFINE_REG(parent);
  __ LoadTaggedField(
      parent, FieldMemOperand(suspender, WasmSuspenderObject::kParentOffset));
  int32_t active_suspender_offset =
      MacroAssembler::RootRegisterOffsetForRootIndex(
          RootIndex::kActiveSuspender);
  __ str(parent, MemOperand(kRootRegister, active_suspender_offset));
  regs.ResetExcept(suspender, caller, stack);
 
  // -------------------------------------------
  // Load jump buffer.
  // -------------------------------------------
  SwitchStacks(masm, stack, false, {caller, suspender});
  FREE_REG(stack);
  __ LoadTaggedField(
      kReturnRegister0,
      FieldMemOperand(suspender, WasmSuspenderObject::kPromiseOffset));
  MemOperand GCScanSlotPlace =
      MemOperand(fp, StackSwitchFrameConstants::kGCScanSlotCountOffset);
  __ Zero(GCScanSlotPlace);
  ASSIGN_REG(scratch)
  LoadJumpBuffer(masm, caller, true, scratch, wasm::JumpBuffer::Inactive);
  if (v8_flags.debug_code) {
    __ Trap();
  }
  __ bind(&resume);
  __ LeaveFrame(StackFrame::STACK_SWITCH);
  __ Jump(lr);
}
 
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();
  __ EnterFrame(StackFrame::STACK_SWITCH);
 
  DEFINE_PINNED(closure, kJSFunctionRegister);  // r1
 
  __ sub(
      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_stack);
  __ LoadRootRelative(active_stack, IsolateData::active_stack_offset());
  DEFINE_REG(scratch);
  FillJumpBuffer(masm, active_stack, &suspend, scratch);
  SwitchStackState(masm, active_stack, scratch, wasm::JumpBuffer::Active,
                   wasm::JumpBuffer::Inactive);
 
  // -------------------------------------------
  // Set the suspender and stack 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, kLRHasBeenSaved,
                      SaveFPRegsMode::kIgnore);
  int32_t active_suspender_offset =
      MacroAssembler::RootRegisterOffsetForRootIndex(
          RootIndex::kActiveSuspender);
  __ str(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_REG(target_stack);
  suspender = target_stack;
  __ ldr(target_stack,
         FieldMemOperand(suspender, WasmSuspenderObject::kStackOffset));
  suspender = no_reg;
 
  __ StoreRootRelative(IsolateData::active_stack_offset(), target_stack);
  SwitchStacks(masm, active_stack, false, {target_stack});
  regs.ResetExcept(target_stack);
 
  // -------------------------------------------
  // Load state from target jmpbuf (longjmp).
  // -------------------------------------------
  regs.Reserve(kReturnRegister0);
  ASSIGN_REG(scratch);
  // Move resolved value to return register.
  __ ldr(kReturnRegister0, MemOperand(fp, 3 * kSystemPointerSize));
  MemOperand GCScanSlotPlace =
      MemOperand(fp, StackSwitchFrameConstants::kGCScanSlotCountOffset);
  __ Zero(GCScanSlotPlace);
  if (on_resume == wasm::OnResume::kThrow) {
    // Switch without restoring the PC.
    LoadJumpBuffer(masm, target_stack, 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 stack normally.
    LoadJumpBuffer(masm, target_stack, true, scratch,
                   wasm::JumpBuffer::Suspended);
  }
  if (v8_flags.debug_code) {
    __ Trap();
  }
  __ bind(&suspend);
  __ LeaveFrame(StackFrame::STACK_SWITCH);
  // Pop receiver + parameter.
  __ add(sp, sp, Operand(2 * kSystemPointerSize));
  __ Jump(lr);
}
}  // 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 SwitchToAllocatedStack(MacroAssembler* masm, RegisterAllocator& regs,
                            Register wasm_instance, Register wrapper_buffer,
                            Register& original_fp, Register& new_wrapper_buffer,
                            Label* suspend) {
  ResetStackSwitchFrameStackSlots(masm);
  DEFINE_SCOPED(scratch)
  DEFINE_REG(target_stack)
  __ LoadRootRelative(target_stack, IsolateData::active_stack_offset());
  DEFINE_REG(parent_stack)
  __ ldr(parent_stack, MemOperand(target_stack, wasm::kStackParentOffset));
 
  FillJumpBuffer(masm, parent_stack, suspend, scratch);
  SwitchStacks(masm, parent_stack, false, {wasm_instance, wrapper_buffer});
 
  FREE_REG(parent_stack);
  // Save the old stack's fp in x9, and use it to access the parameters in
  // the parent frame.
  regs.Pinned(r9, &original_fp);
  __ Move(original_fp, fp);
  __ LoadRootRelative(target_stack, IsolateData::active_stack_offset());
  LoadTargetJumpBuffer(masm, target_stack, scratch,
                       wasm::JumpBuffer::Suspended);
  FREE_REG(target_stack);
 
  // 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);
  __ sub(sp, sp, Operand(stack_space));
  __ EnforceStackAlignment();
 
  ASSIGN_REG(new_wrapper_buffer)
 
  __ Move(new_wrapper_buffer, sp);
  // Copy data needed for return handling from old wrapper buffer to new one.
 
  __ ldr(scratch,
         MemOperand(wrapper_buffer,
                    JSToWasmWrapperFrameConstants::kWrapperBufferReturnCount));
  __ str(scratch,
         MemOperand(new_wrapper_buffer,
                    JSToWasmWrapperFrameConstants::kWrapperBufferReturnCount));
  __ ldr(
      scratch,
      MemOperand(wrapper_buffer,
                 JSToWasmWrapperFrameConstants::kWrapperBufferRefReturnCount));
  __ str(
      scratch,
      MemOperand(new_wrapper_buffer,
                 JSToWasmWrapperFrameConstants::kWrapperBufferRefReturnCount));
  __ ldr(
      scratch,
      MemOperand(
          wrapper_buffer,
          JSToWasmWrapperFrameConstants::kWrapperBufferSigRepresentationArray));
  __ str(
      scratch,
      MemOperand(
          new_wrapper_buffer,
          JSToWasmWrapperFrameConstants::kWrapperBufferSigRepresentationArray));
 
  __ ldr(
      scratch,
      MemOperand(
          wrapper_buffer,
          JSToWasmWrapperFrameConstants::kWrapperBufferSigRepresentationArray +
              4));
  __ str(
      scratch,
      MemOperand(
          new_wrapper_buffer,
          JSToWasmWrapperFrameConstants::kWrapperBufferSigRepresentationArray +
              4));
}
 
void SwitchBackAndReturnPromise(MacroAssembler* masm, RegisterAllocator& regs,
                                wasm::Promise mode, Label* return_promise) {
  regs.ResetExcept();
  // 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));
  }
  __ ldr(kContextRegister,
         MemOperand(fp, StackSwitchFrameConstants::kImplicitArgOffset));
  GetContextFromImplicitArg(masm, kContextRegister, tmp);
 
  ReloadParentStack(masm, promise, return_value, kContextRegister, tmp, tmp2,
                    tmp3);
  RestoreParentSuspender(masm, tmp);
 
  if (mode == wasm::kPromise) {
    __ Move(tmp, Operand(1));
    __ str(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) {
  regs.ResetExcept();
  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);
  thread_in_wasm_flag_addr = r2;
 
  // Unset thread_in_wasm_flag.
  __ ldr(
      thread_in_wasm_flag_addr,
      MemOperand(kRootRegister, Isolate::thread_in_wasm_flag_address_offset()));
  __ Zero(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.
  __ Move(reason, kReturnRegister0);
  __ LoadRoot(promise, RootIndex::kActiveSuspender);
  __ LoadTaggedField(
      promise, FieldMemOperand(promise, WasmSuspenderObject::kPromiseOffset));
 
  DEFINE_SCOPED(tmp);
  DEFINE_SCOPED(tmp2);
  DEFINE_SCOPED(tmp3);
  __ ldr(kContextRegister,
         MemOperand(fp, StackSwitchFrameConstants::kImplicitArgOffset));
  GetContextFromImplicitArg(masm, kContextRegister, tmp);
  ReloadParentStack(masm, promise, reason, kContextRegister, tmp, tmp2, tmp3);
  RestoreParentSuspender(masm, tmp);
 
  __ Move(tmp, Operand(1));
  __ str(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);
 
  __ AllocateStackSpace(StackSwitchFrameConstants::kNumSpillSlots *
                        kSystemPointerSize);
 
  // Load the implicit argument (instance data or import data) from the frame.
  DEFINE_PINNED(implicit_arg, kWasmImplicitArgRegister);
  __ ldr(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);
 
  {
    __ str(new_wrapper_buffer,
           MemOperand(fp, JSToWasmWrapperFrameConstants::kWrapperBufferOffset));
    if (stack_switch) {
      __ str(implicit_arg,
             MemOperand(fp, StackSwitchFrameConstants::kImplicitArgOffset));
      DEFINE_SCOPED(scratch)
      __ ldr(
          scratch,
          MemOperand(original_fp,
                     JSToWasmWrapperFrameConstants::kResultArrayParamOffset));
      __ str(scratch,
             MemOperand(fp, StackSwitchFrameConstants::kResultArrayOffset));
    }
  }
  {
    DEFINE_SCOPED(result_size);
    __ ldr(result_size,
           MemOperand(wrapper_buffer, JSToWasmWrapperFrameConstants::
                                          kWrapperBufferStackReturnBufferSize));
    __ sub(sp, sp, Operand(result_size, LSL, kSystemPointerSizeLog2));
  }
 
  __ str(
      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;
  int param_padding = stack_params_offset & kSystemPointerSize;
  stack_params_offset += param_padding;
 
  {
    DEFINE_SCOPED(params_start);
    __ ldr(params_start,
           MemOperand(wrapper_buffer,
                      JSToWasmWrapperFrameConstants::kWrapperBufferParamStart));
    {
      // Push stack parameters on the stack.
      DEFINE_SCOPED(params_end);
      __ ldr(params_end,
             MemOperand(wrapper_buffer,
                        JSToWasmWrapperFrameConstants::kWrapperBufferParamEnd));
      DEFINE_SCOPED(last_stack_param);
 
      __ add(last_stack_param, params_start, Operand(stack_params_offset));
      Label loop_start;
      __ bind(&loop_start);
 
      Label finish_stack_params;
      __ cmp(last_stack_param, params_end);
      __ b(ge, &finish_stack_params);
 
      // Push parameter
      {
        DEFINE_SCOPED(scratch);
        __ ldr(scratch, MemOperand(params_end, -kSystemPointerSize, PreIndex));
        __ push(scratch);
      }
      __ jmp(&loop_start);
 
      __ bind(&finish_stack_params);
    }
 
    size_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]);
      __ ldr(wasm::kGpParamRegisters[i], MemOperand(params_start, next_offset));
      next_offset += kSystemPointerSize;
    }
 
    next_offset += param_padding;
    for (size_t i = 0; i < arraysize(wasm::kFpParamRegisters); i++) {
      __ vldr(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);
    __ ldr(thread_in_wasm_flag_addr,
           MemOperand(kRootRegister,
                      Isolate::thread_in_wasm_flag_address_offset()));
    DEFINE_SCOPED(scratch);
    __ Move(scratch, Operand(1));
    __ str(scratch, MemOperand(thread_in_wasm_flag_addr, 0));
  }
 
  __ Zero(MemOperand(fp, StackSwitchFrameConstants::kGCScanSlotCountOffset));
  {
    DEFINE_SCOPED(call_target);
    __ ldr(call_target,
           MemOperand(wrapper_buffer,
                      JSToWasmWrapperFrameConstants::kWrapperBufferCallTarget));
    __ CallWasmCodePointer(call_target);
  }
 
  regs.ResetExcept();
  // The wrapper_buffer has to be in r2 as the correct parameter register.
  regs.Reserve(kReturnRegister0, kReturnRegister1);
  ASSIGN_PINNED(wrapper_buffer, r2);
  {
    DEFINE_SCOPED(thread_in_wasm_flag_addr);
    __ ldr(thread_in_wasm_flag_addr,
           MemOperand(kRootRegister,
                      Isolate::thread_in_wasm_flag_address_offset()));
    __ Zero(MemOperand(thread_in_wasm_flag_addr, 0));
  }
 
  __ ldr(wrapper_buffer,
         MemOperand(fp, JSToWasmWrapperFrameConstants::kWrapperBufferOffset));
 
  __ vstr(wasm::kFpReturnRegisters[0],
          MemOperand(
              wrapper_buffer,
              JSToWasmWrapperFrameConstants::kWrapperBufferFPReturnRegister1));
  __ vstr(wasm::kFpReturnRegisters[1],
          MemOperand(
              wrapper_buffer,
              JSToWasmWrapperFrameConstants::kWrapperBufferFPReturnRegister2));
  __ str(wasm::kGpReturnRegisters[0],
         MemOperand(
             wrapper_buffer,
             JSToWasmWrapperFrameConstants::kWrapperBufferGPReturnRegister1));
  __ str(wasm::kGpReturnRegisters[1],
         MemOperand(
             wrapper_buffer,
             JSToWasmWrapperFrameConstants::kWrapperBufferGPReturnRegister2));
  // Call the return value builtin with
  // r0: wasm instance.
  // r1: the result JSArray for multi-return.
  // r2: pointer to the byte buffer which contains all parameters.
  if (stack_switch) {
    __ ldr(r1, MemOperand(fp, StackSwitchFrameConstants::kResultArrayOffset));
    __ ldr(r0, MemOperand(fp, StackSwitchFrameConstants::kImplicitArgOffset));
  } else {
    __ ldr(r1, MemOperand(
                   fp, JSToWasmWrapperFrameConstants::kResultArrayParamOffset));
    __ ldr(r0,
           MemOperand(fp, JSToWasmWrapperFrameConstants::kImplicitArgOffset));
  }
  Register scratch = r3;
  GetContextFromImplicitArg(masm, r0, scratch);
 
  __ 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.
  __ add(sp, sp, Operand(2 * kSystemPointerSize));
  __ Jump(lr);
 
  // Catch handler for the stack-switching wrapper: reject the promise with the
  // thrown exception.
  if (mode == wasm::kPromise) {
    // Block literal pool emission whilst taking the position of the handler
    // entry.
    Assembler::BlockConstPoolScope block_const_pool(masm);
    GenerateExceptionHandlingLandingPad(masm, regs, &return_promise);
  }
  // Emit constant pool now.
  __ CheckConstPool(true, false);
}
}  // namespace
 
void Builtins::Generate_JSToWasmWrapperAsm(MacroAssembler* masm) {
  JSToWasmWrapperHelper(masm, wasm::kNoPromise);
}
 
void Builtins::Generate_WasmReturnPromiseOnSuspendAsm(MacroAssembler* masm) {
  JSToWasmWrapperHelper(masm, wasm::kPromise);
}
 
void Builtins::Generate_JSToWasmStressSwitchStacksAsm(MacroAssembler* masm) {
  JSToWasmWrapperHelper(masm, wasm::kStressSwitch);
}
 
namespace {
 
static constexpr Register kOldSPRegister = r7;
static constexpr Register kSwitchFlagRegister = r8;
 
void SwitchToTheCentralStackIfNeeded(MacroAssembler* masm, Register argc_input,
                                     Register target_input,
                                     Register argv_input) {
  using ER = ExternalReference;
 
  __ Move(kOldSPRegister, sp);
 
  // Using r2 & r3 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());
  __ Move(kSwitchFlagRegister, on_central_stack_flag_loc);
  __ ldrb(kSwitchFlagRegister, MemOperand(kSwitchFlagRegister));
 
  Label do_not_need_to_switch;
  __ cmp(kSwitchFlagRegister, Operand(0));
  __ b(ne, &do_not_need_to_switch);
 
  // Switch to central stack.
 
  Register central_stack_sp = r2;
  DCHECK(!AreAliased(central_stack_sp, argc_input, argv_input, target_input));
  {
    __ Push(argc_input);
    __ Push(target_input);
    __ Push(argv_input);
    __ PrepareCallCFunction(2);
    __ Move(kCArgRegs[0], ER::isolate_address());
    __ Move(kCArgRegs[1], kOldSPRegister);
    __ CallCFunction(ER::wasm_switch_to_the_central_stack(), 2,
                     SetIsolateDataSlots::kNo);
    __ Move(central_stack_sp, kReturnRegister0);
    __ Pop(argv_input);
    __ Pop(target_input);
    __ Pop(argc_input);
  }
 
  static constexpr int kReturnAddressSlotOffset = 1 * kSystemPointerSize;
  static constexpr int kPadding = 1 * kSystemPointerSize;
  __ sub(sp, central_stack_sp, Operand(kReturnAddressSlotOffset + kPadding));
  __ EnforceStackAlignment();
 
  // 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.
  __ add(central_stack_sp, sp, Operand(kSystemPointerSize));
  __ str(central_stack_sp, MemOperand(fp, ExitFrameConstants::kSPOffset));
 
  __ bind(&do_not_need_to_switch);
}
 
void SwitchFromTheCentralStackIfNeeded(MacroAssembler* masm) {
  using ER = ExternalReference;
 
  Label no_stack_change;
 
  __ cmp(kSwitchFlagRegister, Operand(0));
  __ b(ne, &no_stack_change);
 
  {
    __ Push(kReturnRegister0, kReturnRegister1);
    __ PrepareCallCFunction(1);
    __ Move(kCArgRegs[0], ER::isolate_address());
    __ CallCFunction(ER::wasm_switch_from_the_central_stack(), 1,
                     SetIsolateDataSlots::kNo);
    __ Pop(kReturnRegister0, kReturnRegister1);
  }
 
  __ Move(sp, kOldSPRegister);
 
  __ bind(&no_stack_change);
}
 
}  // namespace
 
#endif  // V8_ENABLE_WEBASSEMBLY
 
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.
  // r0: number of arguments including receiver
  // r1: 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:
  // r2: pointer to the first argument
 
  using ER = ExternalReference;
 
  // Move input arguments to more convenient registers.
  static constexpr Register argc_input = r0;
  static constexpr Register target_fun = r5;  // C callee-saved
  static constexpr Register argv = r1;
  static constexpr Register scratch = r3;
  static constexpr Register argc_sav = r4;  // C callee-saved
 
  __ mov(target_fun, Operand(r1));
 
  if (argv_mode == ArgvMode::kRegister) {
    // Move argv into the correct register.
    __ mov(argv, Operand(r2));
  } else {
    // Compute the argv pointer in a callee-saved register.
    __ add(argv, sp, Operand(argc_input, LSL, kPointerSizeLog2));
    __ sub(argv, argv, Operand(kPointerSize));
  }
 
  // 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);
 
  // Store a copy of argc in callee-saved registers for later.
  __ mov(argc_sav, Operand(argc_input));
 
  // r0: number of arguments including receiver
  // r4: number of arguments including receiver  (C callee-saved)
  // r1: pointer to the first argument
  // r5: pointer to builtin function  (C callee-saved)
 
#if V8_HOST_ARCH_ARM
  int frame_alignment = MacroAssembler::ActivationFrameAlignment();
  int frame_alignment_mask = frame_alignment - 1;
  if (v8_flags.debug_code) {
    if (frame_alignment > kPointerSize) {
      Label alignment_as_expected;
      DCHECK(base::bits::IsPowerOfTwo(frame_alignment));
      __ tst(sp, Operand(frame_alignment_mask));
      __ b(eq, &alignment_as_expected);
      // Don't use Check here, as it will call Runtime_Abort re-entering here.
      __ stop();
      __ bind(&alignment_as_expected);
    }
  }
#endif
 
#if V8_ENABLE_WEBASSEMBLY
  if (switch_to_central_stack) {
    SwitchToTheCentralStackIfNeeded(masm, argc_input, target_fun, argv);
  }
#endif  // V8_ENABLE_WEBASSEMBLY
 
  // Call C built-in.
  // r0 = argc, r1 = argv, r2 = isolate, r5 = target_fun
  DCHECK_EQ(kCArgRegs[0], argc_input);
  DCHECK_EQ(kCArgRegs[1], argv);
  __ Move(kCArgRegs[2], ER::isolate_address());
  __ StoreReturnAddressAndCall(target_fun);
 
  // Result returned in r0 or r1:r0 - do not destroy these registers!
 
  // Check result for exception sentinel.
  Label exception_returned;
  __ CompareRoot(r0, RootIndex::kException);
  __ b(eq, &exception_returned);
 
#if V8_ENABLE_WEBASSEMBLY
  if (switch_to_central_stack) {
    SwitchFromTheCentralStackIfNeeded(masm);
  }
#endif  // V8_ENABLE_WEBASSEMBLY
 
  // Check that there is no exception, otherwise we
  // should have returned the exception sentinel.
  if (v8_flags.debug_code) {
    Label okay;
    ER exception_address =
        ER::Create(IsolateAddressId::kExceptionAddress, masm->isolate());
    __ ldr(scratch, __ ExternalReferenceAsOperand(exception_address, no_reg));
    __ CompareRoot(scratch, RootIndex::kTheHoleValue);
    // Cannot use check here as it attempts to generate call into runtime.
    __ b(eq, &okay);
    __ stop();
    __ bind(&okay);
  }
 
  // Exit C frame and return.
  // r0:r1: result
  // sp: stack pointer
  // fp: frame pointer
  // r4: still holds argc (C caller-saved).
  __ LeaveExitFrame(scratch);
  if (argv_mode == ArgvMode::kStack) {
    DCHECK(!AreAliased(scratch, argc_sav));
    __ add(sp, sp, Operand(argc_sav, LSL, kPointerSizeLog2));
  }
 
  __ mov(pc, lr);
 
  // 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 r0 to
  // contain the current exception, don't clobber it.
  {
    FrameScope scope(masm, StackFrame::MANUAL);
    __ PrepareCallCFunction(3, 0);
    __ mov(kCArgRegs[0], Operand(0));
    __ mov(kCArgRegs[1], Operand(0));
    __ Move(kCArgRegs[2], ER::isolate_address());
    __ CallCFunction(ER::Create(Runtime::kUnwindAndFindExceptionHandler), 3,
                     SetIsolateDataSlots::kNo);
  }
 
  // Retrieve the handler context, SP and FP.
  __ Move(cp, pending_handler_context_address);
  __ ldr(cp, MemOperand(cp));
  __ Move(sp, pending_handler_sp_address);
  __ ldr(sp, MemOperand(sp));
  __ Move(fp, pending_handler_fp_address);
  __ ldr(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.
  __ cmp(cp, Operand(0));
  __ str(cp, MemOperand(fp, StandardFrameConstants::kContextOffset), ne);
 
  // Clear c_entry_fp, like we do in `LeaveExitFrame`.
  ER c_entry_fp_address =
      ER::Create(IsolateAddressId::kCEntryFPAddress, masm->isolate());
  __ mov(scratch, Operand::Zero());
  __ str(scratch, __ ExternalReferenceAsOperand(c_entry_fp_address, no_reg));
 
  // Compute the handler entry address and jump to it.
  ConstantPoolUnavailableScope constant_pool_unavailable(masm);
  __ ldr(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);
    __ mov(kCArgRegs[3], gap);
    __ mov(kCArgRegs[1], sp);
    __ sub(kCArgRegs[2], frame_base, kCArgRegs[1]);
    // On Arm we need preserve rbp value somewhere before entering
    // INTERNAL frame later. It will be placed on the stack as an argument.
    __ mov(kCArgRegs[0], fp);
    FrameScope scope(masm, StackFrame::INTERNAL);
    __ push(kCArgRegs[3]);
    __ PrepareCallCFunction(5);
    __ str(kCArgRegs[0], MemOperand(sp, 0 * kPointerSize));  // current_fp.
    __ Move(kCArgRegs[0], ER::isolate_address());
    __ 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.
  __ cmp(kReturnRegister0, Operand(0));
  __ b(eq, &call_runtime);
 
  // Calculate old FP - SP offset to adjust FP accordingly to new SP.
  __ sub(fp, fp, sp);
  __ add(fp, fp, kReturnRegister0);
  __ mov(sp, kReturnRegister0);
  {
    UseScratchRegisterScope temps(masm);
    Register scratch = temps.Acquire();
    __ mov(scratch,
           Operand(StackFrame::TypeToMarker(StackFrame::WASM_SEGMENT_START)));
    __ str(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.
  {
    __ ldr(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 negate, done;
 
  HardAbortScope hard_abort(masm);  // Avoid calls to Abort.
  UseScratchRegisterScope temps(masm);
  Register result_reg = r7;
  Register double_low = GetRegisterThatIsNotOneOf(result_reg);
  Register double_high = GetRegisterThatIsNotOneOf(result_reg, double_low);
  LowDwVfpRegister double_scratch = temps.AcquireLowD();
 
  // Save the old values from these temporary registers on the stack.
  __ Push(result_reg, double_high, double_low);
 
  // Account for saved regs.
  const int kArgumentOffset = 3 * kPointerSize;
 
  MemOperand input_operand(sp, kArgumentOffset);
  MemOperand result_operand = input_operand;
 
  // Load double input.
  __ vldr(double_scratch, input_operand);
  __ vmov(double_low, double_high, double_scratch);
  // Try to convert with a FPU convert instruction. This handles all
  // non-saturating cases.
  __ TryInlineTruncateDoubleToI(result_reg, double_scratch, &done);
 
  Register scratch = temps.Acquire();
  __ Ubfx(scratch, double_high, HeapNumber::kExponentShift,
          HeapNumber::kExponentBits);
  // Load scratch with exponent - 1. This is faster than loading
  // with exponent because Bias + 1 = 1024 which is an *ARM* immediate value.
  static_assert(HeapNumber::kExponentBias + 1 == 1024);
  __ sub(scratch, scratch, Operand(HeapNumber::kExponentBias + 1));
  // If exponent is greater than or equal to 84, the 32 less significant
  // bits are 0s (2^84 = 1, 52 significant bits, 32 uncoded bits),
  // the result is 0.
  // Compare exponent with 84 (compare exponent - 1 with 83). If the exponent is
  // greater than this, the conversion is out of range, so return zero.
  __ cmp(scratch, Operand(83));
  __ mov(result_reg, Operand::Zero(), LeaveCC, ge);
  __ b(ge, &done);
 
  // If we reach this code, 30 <= exponent <= 83.
  // `TryInlineTruncateDoubleToI` above will have truncated any double with an
  // exponent lower than 30.
  if (v8_flags.debug_code) {
    // Scratch is exponent - 1.
    __ cmp(scratch, Operand(30 - 1));
    __ Check(ge, AbortReason::kUnexpectedValue);
  }
 
  // We don't have to handle cases where 0 <= exponent <= 20 for which we would
  // need to shift right the high part of the mantissa.
  // Scratch contains exponent - 1.
  // Load scratch with 52 - exponent (load with 51 - (exponent - 1)).
  __ rsb(scratch, scratch, Operand(51), SetCC);
 
  // 52 <= exponent <= 83, shift only double_low.
  // On entry, scratch contains: 52 - exponent.
  __ rsb(scratch, scratch, Operand::Zero(), LeaveCC, ls);
  __ mov(result_reg, Operand(double_low, LSL, scratch), LeaveCC, ls);
  __ b(ls, &negate);
 
  // 21 <= exponent <= 51, shift double_low and double_high
  // to generate the result.
  __ mov(double_low, Operand(double_low, LSR, scratch));
  // Scratch contains: 52 - exponent.
  // We needs: exponent - 20.
  // So we use: 32 - scratch = 32 - 52 + exponent = exponent - 20.
  __ rsb(scratch, scratch, Operand(32));
  __ Ubfx(result_reg, double_high, 0, HeapNumber::kMantissaBitsInTopWord);
  // Set the implicit 1 before the mantissa part in double_high.
  __ orr(result_reg, result_reg,
         Operand(1 << HeapNumber::kMantissaBitsInTopWord));
  __ orr(result_reg, double_low, Operand(result_reg, LSL, scratch));
 
  __ bind(&negate);
  // If input was positive, double_high ASR 31 equals 0 and
  // double_high LSR 31 equals zero.
  // New result = (result eor 0) + 0 = result.
  // If the input was negative, we have to negate the result.
  // Input_high ASR 31 equals 0xFFFFFFFF and double_high LSR 31 equals 1.
  // New result = (result eor 0xFFFFFFFF) + 1 = 0 - result.
  __ eor(result_reg, result_reg, Operand(double_high, ASR, 31));
  __ add(result_reg, result_reg, Operand(double_high, LSR, 31));
 
  __ bind(&done);
  __ str(result_reg, result_operand);
 
  // Restore registers corrupted in this routine and return.
  __ Pop(result_reg, double_high, double_low);
  __ Ret();
}
 
void Builtins::Generate_CallApiCallbackImpl(MacroAssembler* masm,
                                            CallApiCallbackMode mode) {
  // ----------- S t a t e -------------
  // CallApiCallbackMode::kOptimizedNoProfiling/kOptimized modes:
  //  -- r1                  : api function address
  // Both modes:
  //  -- r2                  : arguments count (not including the receiver)
  //  -- r3                  : 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 = r4;
 
  switch (mode) {
    case CallApiCallbackMode::kGeneric:
      argc = CallApiCallbackGenericDescriptor::ActualArgumentsCountRegister();
      topmost_script_having_context = CallApiCallbackGenericDescriptor::
          TopmostScriptHavingContextRegister();
      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[1 * kSystemPointerSize]: kUnused   <= FCA::implicit_args_
  //   sp[2 * kSystemPointerSize]: kIsolate
  //   sp[3 * kSystemPointerSize]: kContext
  //   sp[4 * kSystemPointerSize]: undefined (kReturnValue)
  //   sp[5 * kSystemPointerSize]: kTarget
  //   sp[6 * kSystemPointerSize]: undefined (kNewTarget)
  // Existing state:
  //   sp[7 * 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.
  __ AllocateStackSpace(FCA::kArgsLength * kSystemPointerSize);
 
  // kIsolate.
  __ Move(scratch, ER::isolate_address());
  __ str(scratch, MemOperand(sp, FCA::kIsolateIndex * kSystemPointerSize));
 
  // kContext.
  __ str(cp, MemOperand(sp, FCA::kContextIndex * kSystemPointerSize));
 
  // kReturnValue.
  __ LoadRoot(scratch, RootIndex::kUndefinedValue);
  __ str(scratch, MemOperand(sp, FCA::kReturnValueIndex * kSystemPointerSize));
 
  // kTarget.
  __ str(func_templ, MemOperand(sp, FCA::kTargetIndex * kSystemPointerSize));
 
  // kNewTarget.
  __ str(scratch, MemOperand(sp, FCA::kNewTargetIndex * kSystemPointerSize));
 
  // kUnused.
  __ str(scratch, MemOperand(sp, FCA::kUnusedIndex * kSystemPointerSize));
 
  FrameScope frame_scope(masm, StackFrame::MANUAL);
  if (mode == CallApiCallbackMode::kGeneric) {
    __ ldr(
        api_function_address,
        FieldMemOperand(func_templ,
                        FunctionTemplateInfo::kMaybeRedirectedCallbackOffset));
  }
  __ 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.
    __ str(argc, argc_operand);
 
    // FunctionCallbackInfo::implicit_args_.
    __ add(scratch, fp, Operand(FC::kImplicitArgsArrayOffset));
    __ str(scratch, MemOperand(fp, FC::kFCIImplicitArgsOffset));
 
    // FunctionCallbackInfo::values_ (points at JS arguments on the stack).
    __ add(scratch, fp, Operand(FC::kFirstArgumentOffset));
    __ str(scratch, MemOperand(fp, FC::kFCIValuesOffset));
  }
 
  __ RecordComment("v8::FunctionCallback's argument.");
  __ add(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
  //  -- r1                  : receiver
  //  -- r3                  : accessor info
  //  -- r0                  : holder
  // -----------------------------------
 
  // 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
 
  Register name_arg = kCArgRegs[0];
  Register property_callback_info_arg = kCArgRegs[1];
 
  Register api_function_address = r2;
  Register receiver = ApiGetterDescriptor::ReceiverRegister();
  Register holder = ApiGetterDescriptor::HolderRegister();
  Register callback = ApiGetterDescriptor::CallbackRegister();
  Register scratch = r4;
  Register smi_zero = r5;
 
  DCHECK(!AreAliased(receiver, holder, callback, scratch, smi_zero));
 
  __ ldr(scratch, FieldMemOperand(callback, AccessorInfo::kDataOffset));
  __ Push(receiver, scratch);  // kThisIndex, kDataIndex
  __ LoadRoot(scratch, RootIndex::kUndefinedValue);
  __ Move(smi_zero, Smi::zero());
  __ Push(scratch, smi_zero);  // kReturnValueIndex, kHolderV2Index
  __ Move(scratch, ER::isolate_address());
  __ Push(scratch, holder);  // kIsolateIndex, kHolderIndex
 
  __ ldr(name_arg, FieldMemOperand(callback, AccessorInfo::kNameOffset));
  static_assert(kDontThrow == 0);
  __ Push(smi_zero, name_arg);  // should_throw_on_error -> kDontThrow, name
 
  __ RecordComment("Load api_function_address");
  __ ldr(api_function_address,
         FieldMemOperand(callback, AccessorInfo::kMaybeRedirectedGetterOffset));
 
  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&
  __ add(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);
  __ mov(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.
 
  __ str(lr, MemOperand(sp, 0));  // Store the return address.
  __ blx(ip);                     // Call the C++ function.
  __ ldr(pc, MemOperand(sp, 0));  // Return to calling code.
}
 
void Builtins::Generate_MemCopyUint8Uint8(MacroAssembler* masm) {
  Register dest = r0;
  Register src = r1;
  Register chars = r2;
  Register temp1 = r3;
  Label less_4;
 
  {
    UseScratchRegisterScope temps(masm);
    Register temp2 = temps.Acquire();
    Label loop;
 
    __ bic(temp2, chars, Operand(0x3), SetCC);
    __ b(&less_4, eq);
    __ add(temp2, dest, temp2);
 
    __ bind(&loop);
    __ ldr(temp1, MemOperand(src, 4, PostIndex));
    __ str(temp1, MemOperand(dest, 4, PostIndex));
    __ cmp(dest, temp2);
    __ b(&loop, ne);
  }
 
  __ bind(&less_4);
  __ mov(chars, Operand(chars, LSL, 31), SetCC);
  // bit0 => Z (ne), bit1 => C (cs)
  __ ldrh(temp1, MemOperand(src, 2, PostIndex), cs);
  __ strh(temp1, MemOperand(dest, 2, PostIndex), cs);
  __ ldrb(temp1, MemOperand(src), ne);
  __ strb(temp1, MemOperand(dest), ne);
  __ Ret();
}
 
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();
 
  // Note: This is an overapproximation; we always reserve space for 32 double
  // registers, even though the actual CPU may only support 16. In the latter
  // case, SaveFPRegs and RestoreFPRegs still use 32 stack slots, but only fill
  // 16.
  static constexpr int kDoubleRegsSize =
      kDoubleSize * DwVfpRegister::kNumRegisters;
 
  // Save all allocatable VFP registers before messing with them.
  {
    UseScratchRegisterScope temps(masm);
    Register scratch = temps.Acquire();
    __ SaveFPRegs(sp, scratch);
  }
 
  // Save all general purpose registers before messing with them.
  static constexpr int kNumberOfRegisters = Register::kNumRegisters;
  static_assert(kNumberOfRegisters == 16);
 
  // Everything but pc, lr and ip which will be saved but not restored.
  RegList restored_regs = kJSCallerSaved | kCalleeSaved | RegList{ip};
 
  // Push all 16 registers (needed to populate FrameDescription::registers_).
  // TODO(v8:1588): Note that using pc with stm is deprecated, so we should
  // perhaps handle this a bit differently.
  __ stm(db_w, sp, restored_regs | RegList{sp, lr, pc});
 
  {
    UseScratchRegisterScope temps(masm);
    Register scratch = temps.Acquire();
    __ Move(scratch, ExternalReference::Create(
                         IsolateAddressId::kCEntryFPAddress, isolate));
    __ str(fp, MemOperand(scratch));
  }
 
  static constexpr int kSavedRegistersAreaSize =
      (kNumberOfRegisters * kPointerSize) + kDoubleRegsSize;
 
  // Get the address of the location in the code object (r3) (return
  // address for lazy deoptimization) and compute the fp-to-sp delta in
  // register r4.
  __ mov(r2, lr);
  __ add(r3, sp, Operand(kSavedRegistersAreaSize));
  __ sub(r3, fp, r3);
 
  // Allocate a new deoptimizer object.
  // Pass four arguments in r0 to r3 and fifth argument on stack.
  __ PrepareCallCFunction(5);
  __ mov(r0, Operand(0));
  Label context_check;
  __ ldr(r1, MemOperand(fp, CommonFrameConstants::kContextOrFrameTypeOffset));
  __ JumpIfSmi(r1, &context_check);
  __ ldr(r0, MemOperand(fp, StandardFrameConstants::kFunctionOffset));
  __ bind(&context_check);
  __ mov(r1, Operand(static_cast<int>(deopt_kind)));
  // r2: code address or 0 already loaded.
  // r3: Fp-to-sp delta already loaded.
  __ Move(r4, ExternalReference::isolate_address());
  __ str(r4, MemOperand(sp, 0 * kPointerSize));  // Isolate.
  // Call Deoptimizer::New().
  {
    AllowExternalCallThatCantCauseGC scope(masm);
    __ CallCFunction(ExternalReference::new_deoptimizer_function(), 5);
  }
 
  // Preserve "deoptimizer" object in register r0 and get the input
  // frame descriptor pointer to r1 (deoptimizer->input_);
  __ ldr(r1, MemOperand(r0, Deoptimizer::input_offset()));
 
  // Copy core registers into FrameDescription::registers_.
  DCHECK_EQ(Register::kNumRegisters, kNumberOfRegisters);
  for (int i = 0; i < kNumberOfRegisters; i++) {
    int offset = (i * kPointerSize) + FrameDescription::registers_offset();
    __ ldr(r2, MemOperand(sp, i * kPointerSize));
    __ str(r2, MemOperand(r1, offset));
  }
 
  // Copy simd128 / double registers to the FrameDescription.
  static constexpr int kSimd128RegsOffset =
      FrameDescription::simd128_registers_offset();
  {
    UseScratchRegisterScope temps(masm);
    Register scratch = temps.Acquire();
    Register src_location = r4;
    __ add(src_location, sp, Operand(kNumberOfRegisters * kPointerSize));
    __ RestoreFPRegs(src_location, scratch);
 
    Register dst_location = r4;
    __ add(dst_location, r1, Operand(kSimd128RegsOffset));
    __ SaveFPRegsToHeap(dst_location, scratch);
  }
 
  // Mark the stack as not iterable for the CPU profiler which won't be able to
  // walk the stack without the return address.
  {
    UseScratchRegisterScope temps(masm);
    Register is_iterable = temps.Acquire();
    Register zero = r4;
    __ LoadIsolateField(is_iterable, IsolateFieldId::kStackIsIterable);
    __ mov(zero, Operand(0));
    __ strb(zero, MemOperand(is_iterable));
  }
 
  // Remove the saved registers from the stack.
  __ add(sp, sp, Operand(kSavedRegistersAreaSize));
 
  // Compute a pointer to the unwinding limit in register r2; that is
  // the first stack slot not part of the input frame.
  __ ldr(r2, MemOperand(r1, FrameDescription::frame_size_offset()));
  __ add(r2, r2, 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.
  __ add(r3, r1, Operand(FrameDescription::frame_content_offset()));
  Label pop_loop;
  Label pop_loop_header;
  __ b(&pop_loop_header);
  __ bind(&pop_loop);
  __ pop(r4);
  __ str(r4, MemOperand(r3, 0));
  __ add(r3, r3, Operand(sizeof(uint32_t)));
  __ bind(&pop_loop_header);
  __ cmp(r2, sp);
  __ b(ne, &pop_loop);
 
  // Compute the output frame in the deoptimizer.
  __ push(r0);  // Preserve deoptimizer object across call.
  // r0: deoptimizer object; r1: scratch.
  __ PrepareCallCFunction(1);
  // Call Deoptimizer::ComputeOutputFrames().
  {
    AllowExternalCallThatCantCauseGC scope(masm);
    __ CallCFunction(ExternalReference::compute_output_frames_function(), 1);
  }
  __ pop(r0);  // Restore deoptimizer object (class Deoptimizer).
 
  __ ldr(sp, MemOperand(r0, 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: r4 = current "FrameDescription** output_",
  // r1 = one past the last FrameDescription**.
  __ ldr(r1, MemOperand(r0, Deoptimizer::output_count_offset()));
  __ ldr(r4, MemOperand(r0, Deoptimizer::output_offset()));  // r4 is output_.
  __ add(r1, r4, Operand(r1, LSL, 2));
  __ jmp(&outer_loop_header);
  __ bind(&outer_push_loop);
  // Inner loop state: r2 = current FrameDescription*, r3 = loop index.
  __ ldr(r2, MemOperand(r4, 0));  // output_[ix]
  __ ldr(r3, MemOperand(r2, FrameDescription::frame_size_offset()));
  __ jmp(&inner_loop_header);
  __ bind(&inner_push_loop);
  __ sub(r3, r3, Operand(sizeof(uint32_t)));
  __ add(r6, r2, Operand(r3));
  __ ldr(r6, MemOperand(r6, FrameDescription::frame_content_offset()));
  __ push(r6);
  __ bind(&inner_loop_header);
  __ cmp(r3, Operand::Zero());
  __ b(ne, &inner_push_loop);  // test for gt?
  __ add(r4, r4, Operand(kPointerSize));
  __ bind(&outer_loop_header);
  __ cmp(r4, r1);
  __ b(lt, &outer_push_loop);
 
  __ ldr(r1, MemOperand(r0, Deoptimizer::input_offset()));
 
  // State:
  // r1: Deoptimizer::input_ (FrameDescription*).
  // r2: The last output FrameDescription pointer (FrameDescription*).
 
  // Restore double registers from the output frame description.
  {
    UseScratchRegisterScope temps(masm);
    Register scratch = temps.Acquire();
    Register src_location = r6;
    __ add(src_location, r2, Operand(kSimd128RegsOffset));
    __ RestoreFPRegsFromHeap(src_location, scratch);
  }
 
  // Push pc and continuation from the last output frame.
  __ ldr(r6, MemOperand(r2, FrameDescription::pc_offset()));
  __ push(r6);
  __ ldr(r6, MemOperand(r2, FrameDescription::continuation_offset()));
  __ push(r6);
 
  // Push the registers from the last output frame.
  for (int i = kNumberOfRegisters - 1; i >= 0; i--) {
    int offset = (i * kPointerSize) + FrameDescription::registers_offset();
    __ ldr(r6, MemOperand(r2, offset));
    __ push(r6);
  }
 
  // Restore the registers from the stack.
  __ ldm(ia_w, sp, restored_regs);  // all but pc registers.
 
  {
    UseScratchRegisterScope temps(masm);
    Register is_iterable = temps.Acquire();
    Register one = r4;
    __ push(one);  // Save the value from the output FrameDescription.
    __ LoadIsolateField(is_iterable, IsolateFieldId::kStackIsIterable);
    __ mov(one, Operand(1));
    __ strb(one, MemOperand(is_iterable));
    __ pop(one);  // Restore the value from the output FrameDescription.
  }
 
  // Remove sp, lr and pc.
  __ Drop(3);
  {
    UseScratchRegisterScope temps(masm);
    Register scratch = temps.Acquire();
    __ pop(scratch);  // get continuation, leave pc on stack
    __ pop(lr);
    Label end;
    __ cmp(scratch, Operand::Zero());
    __ b(eq, &end);
    __ Jump(scratch);
    __ 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 = r1;
  __ ldr(closure, MemOperand(fp, StandardFrameConstants::kFunctionOffset));
 
  // Get the InstructionStream object from the shared function info.
  Register code_obj = r4;
  __ ldr(code_obj,
         FieldMemOperand(closure, JSFunction::kSharedFunctionInfoOffset));
 
  ResetSharedFunctionInfoAge(masm, code_obj, r3);
 
  __ ldr(code_obj,
         FieldMemOperand(code_obj,
                         SharedFunctionInfo::kTrustedFunctionDataOffset));
 
  // For OSR entry it is safe to assume we always have baseline code.
  if (v8_flags.debug_code) {
    __ CompareObjectType(code_obj, r3, r3, CODE_TYPE);
    __ Assert(eq, AbortReason::kExpectedBaselineData);
    AssertCodeIsBaseline(masm, code_obj, r3);
  }
 
  // Load the feedback cell and vector.
  Register feedback_cell = r2;
  Register feedback_vector = r9;
  __ ldr(feedback_cell,
         FieldMemOperand(closure, JSFunction::kFeedbackCellOffset));
  __ ldr(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.
  __ CompareObjectType(feedback_vector, r3, r3, FEEDBACK_VECTOR_TYPE);
  __ b(ne, &install_baseline_code);
 
  // Save BytecodeOffset from the stack frame.
  __ ldr(kInterpreterBytecodeOffsetRegister,
         MemOperand(fp, InterpreterFrameConstants::kBytecodeOffsetFromFp));
  __ SmiUntag(kInterpreterBytecodeOffsetRegister);
  // Replace bytecode offset with feedback cell.
  static_assert(InterpreterFrameConstants::kBytecodeOffsetFromFp ==
                BaselineFrameConstants::kFeedbackCellFromFp);
  __ str(feedback_cell,
         MemOperand(fp, BaselineFrameConstants::kFeedbackCellFromFp));
  feedback_cell = no_reg;
  // Update feedback vector cache.
  static_assert(InterpreterFrameConstants::kFeedbackVectorFromFp ==
                BaselineFrameConstants::kFeedbackVectorFromFp);
  __ str(feedback_vector,
         MemOperand(fp, InterpreterFrameConstants::kFeedbackVectorFromFp));
  feedback_vector = no_reg;
 
  // Compute baseline pc for bytecode offset.
  Register get_baseline_pc = r3;
  __ Move(get_baseline_pc,
          ExternalReference::baseline_pc_for_next_executed_bytecode());
 
  __ sub(kInterpreterBytecodeOffsetRegister, kInterpreterBytecodeOffsetRegister,
         Operand(BytecodeArray::kHeaderSize - kHeapObjectTag));
 
  // Get bytecode array from the stack frame.
  __ ldr(kInterpreterBytecodeArrayRegister,
         MemOperand(fp, InterpreterFrameConstants::kBytecodeArrayFromFp));
  // Save the accumulator register, since it's clobbered by the below call.
  __ Push(kInterpreterAccumulatorRegister);
  {
    __ mov(kCArgRegs[0], code_obj);
    __ mov(kCArgRegs[1], kInterpreterBytecodeOffsetRegister);
    __ mov(kCArgRegs[2], kInterpreterBytecodeArrayRegister);
    FrameScope scope(masm, StackFrame::INTERNAL);
    __ PrepareCallCFunction(3, 0);
    __ CallCFunction(get_baseline_pc, 3, 0);
  }
  __ LoadCodeInstructionStart(code_obj, code_obj);
  __ add(code_obj, code_obj, kReturnRegister0);
  __ Pop(kInterpreterAccumulatorRegister);
 
  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.
  __ b(&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.
 
  __ ldr(r1, MemOperand(fp, StandardFrameConstants::kFunctionOffset));
  __ ldr(r0, MemOperand(fp, StandardFrameConstants::kArgCOffset));
  __ LeaveFrame(StackFrame::INTERNAL);
 
  // The arguments are already in the stack (including any necessary padding),
  // we should not try to massage the arguments again.
  __ mov(r2, Operand(kDontAdaptArgumentsSentinel));
  __ InvokeFunction(r1, r2, r0, InvokeType::kJump);
}
 
#undef __
 
}  // namespace internal
}  // namespace v8
 
#endif  // V8_TARGET_ARCH_ARM