src/mips/builtins-mips.cc

// Copyright 2011 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
//       notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
//       copyright notice, this list of conditions and the following
//       disclaimer in the documentation and/or other materials provided
//       with the distribution.
//     * Neither the name of Google Inc. nor the names of its
//       contributors may be used to endorse or promote products derived
//       from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.



#include "v8.h"

#if defined(V8_TARGET_ARCH_MIPS)

#include "codegen.h"
#include "debug.h"
#include "deoptimizer.h"
#include "full-codegen.h"
#include "runtime.h"

namespace v8 {
namespace internal {


#define __ ACCESS_MASM(masm)


void Builtins::Generate_Adaptor(MacroAssembler* masm,
                                CFunctionId id,
                                BuiltinExtraArguments extra_args) {
  // ----------- S t a t e -------------
  //  -- a0                 : number of arguments excluding receiver
  //  -- a1                 : called function (only guaranteed when
  //  --                      extra_args requires it)
  //  -- cp                 : context
  //  -- sp[0]              : last argument
  //  -- ...
  //  -- sp[4 * (argc - 1)] : first argument
  //  -- sp[4 * agrc]       : receiver
  // -----------------------------------

  // Insert extra arguments.
  int num_extra_args = 0;
  if (extra_args == NEEDS_CALLED_FUNCTION) {
    num_extra_args = 1;
    __ push(a1);
  } else {
    ASSERT(extra_args == NO_EXTRA_ARGUMENTS);
  }

  // JumpToExternalReference expects a0 to contain the number of arguments
  // including the receiver and the extra arguments.
  __ Addu(a0, a0, Operand(num_extra_args + 1));
  __ JumpToExternalReference(ExternalReference(id, masm->isolate()));
}


// Load the built-in Array function from the current context.
static void GenerateLoadArrayFunction(MacroAssembler* masm, Register result) {
  // Load the global context.

  __ lw(result, MemOperand(cp, Context::SlotOffset(Context::GLOBAL_INDEX)));
  __ lw(result,
         FieldMemOperand(result, GlobalObject::kGlobalContextOffset));
  // Load the Array function from the global context.
  __ lw(result,
         MemOperand(result,
                    Context::SlotOffset(Context::ARRAY_FUNCTION_INDEX)));
}


// This constant has the same value as JSArray::kPreallocatedArrayElements and
// if JSArray::kPreallocatedArrayElements is changed handling of loop unfolding
// below should be reconsidered.
static const int kLoopUnfoldLimit = 4;


// Allocate an empty JSArray. The allocated array is put into the result
// register. An elements backing store is allocated with size initial_capacity
// and filled with the hole values.
static void AllocateEmptyJSArray(MacroAssembler* masm,
                                 Register array_function,
                                 Register result,
                                 Register scratch1,
                                 Register scratch2,
                                 Register scratch3,
                                 int initial_capacity,
                                 Label* gc_required) {
  ASSERT(initial_capacity > 0);
  // Load the initial map from the array function.
  __ lw(scratch1, FieldMemOperand(array_function,
                                  JSFunction::kPrototypeOrInitialMapOffset));

  // Allocate the JSArray object together with space for a fixed array with the
  // requested elements.
  int size = JSArray::kSize + FixedArray::SizeFor(initial_capacity);
  __ AllocateInNewSpace(size,
                        result,
                        scratch2,
                        scratch3,
                        gc_required,
                        TAG_OBJECT);
  // Allocated the JSArray. Now initialize the fields except for the elements
  // array.
  // result: JSObject
  // scratch1: initial map
  // scratch2: start of next object
  __ sw(scratch1, FieldMemOperand(result, JSObject::kMapOffset));
  __ LoadRoot(scratch1, Heap::kEmptyFixedArrayRootIndex);
  __ sw(scratch1, FieldMemOperand(result, JSArray::kPropertiesOffset));
  // Field JSArray::kElementsOffset is initialized later.
  __ mov(scratch3,  zero_reg);
  __ sw(scratch3, FieldMemOperand(result, JSArray::kLengthOffset));

  // Calculate the location of the elements array and set elements array member
  // of the JSArray.
  // result: JSObject
  // scratch2: start of next object
  __ Addu(scratch1, result, Operand(JSArray::kSize));
  __ sw(scratch1, FieldMemOperand(result, JSArray::kElementsOffset));

  // Clear the heap tag on the elements array.
  __ And(scratch1, scratch1, Operand(~kHeapObjectTagMask));

  // Initialize the FixedArray and fill it with holes. FixedArray length is
  // stored as a smi.
  // result: JSObject
  // scratch1: elements array (untagged)
  // scratch2: start of next object
  __ LoadRoot(scratch3, Heap::kFixedArrayMapRootIndex);
  ASSERT_EQ(0 * kPointerSize, FixedArray::kMapOffset);
  __ sw(scratch3, MemOperand(scratch1));
  __ Addu(scratch1, scratch1, kPointerSize);
  __ li(scratch3,  Operand(Smi::FromInt(initial_capacity)));
  ASSERT_EQ(1 * kPointerSize, FixedArray::kLengthOffset);
  __ sw(scratch3, MemOperand(scratch1));
  __ Addu(scratch1, scratch1, kPointerSize);

  // Fill the FixedArray with the hole value.
  ASSERT_EQ(2 * kPointerSize, FixedArray::kHeaderSize);
  ASSERT(initial_capacity <= kLoopUnfoldLimit);
  __ LoadRoot(scratch3, Heap::kTheHoleValueRootIndex);
  for (int i = 0; i < initial_capacity; i++) {
    __ sw(scratch3, MemOperand(scratch1));
    __ Addu(scratch1, scratch1, kPointerSize);
  }
}


// Allocate a JSArray with the number of elements stored in a register. The
// register array_function holds the built-in Array function and the register
// array_size holds the size of the array as a smi. The allocated array is put
// into the result register and beginning and end of the FixedArray elements
// storage is put into registers elements_array_storage and elements_array_end
// (see  below for when that is not the case). If the parameter fill_with_holes
// is true the allocated elements backing store is filled with the hole values
// otherwise it is left uninitialized. When the backing store is filled the
// register elements_array_storage is scratched.
static void AllocateJSArray(MacroAssembler* masm,
                            Register array_function,  // Array function.
                            Register array_size,  // As a smi.
                            Register result,
                            Register elements_array_storage,
                            Register elements_array_end,
                            Register scratch1,
                            Register scratch2,
                            bool fill_with_hole,
                            Label* gc_required) {
  Label not_empty, allocated;

  // Load the initial map from the array function.
  __ lw(elements_array_storage,
         FieldMemOperand(array_function,
                         JSFunction::kPrototypeOrInitialMapOffset));

  // Check whether an empty sized array is requested.
  __ Branch(&not_empty, ne, array_size, Operand(zero_reg));

  // If an empty array is requested allocate a small elements array anyway. This
  // keeps the code below free of special casing for the empty array.
  int size = JSArray::kSize +
             FixedArray::SizeFor(JSArray::kPreallocatedArrayElements);
  __ AllocateInNewSpace(size,
                        result,
                        elements_array_end,
                        scratch1,
                        gc_required,
                        TAG_OBJECT);
  __ Branch(&allocated);

  // Allocate the JSArray object together with space for a FixedArray with the
  // requested number of elements.
  __ bind(&not_empty);
  ASSERT(kSmiTagSize == 1 && kSmiTag == 0);
  __ li(elements_array_end,
        (JSArray::kSize + FixedArray::kHeaderSize) / kPointerSize);
  __ sra(scratch1, array_size, kSmiTagSize);
  __ Addu(elements_array_end, elements_array_end, scratch1);
  __ AllocateInNewSpace(
      elements_array_end,
      result,
      scratch1,
      scratch2,
      gc_required,
      static_cast<AllocationFlags>(TAG_OBJECT | SIZE_IN_WORDS));

  // Allocated the JSArray. Now initialize the fields except for the elements
  // array.
  // result: JSObject
  // elements_array_storage: initial map
  // array_size: size of array (smi)
  __ bind(&allocated);
  __ sw(elements_array_storage, FieldMemOperand(result, JSObject::kMapOffset));
  __ LoadRoot(elements_array_storage, Heap::kEmptyFixedArrayRootIndex);
  __ sw(elements_array_storage,
         FieldMemOperand(result, JSArray::kPropertiesOffset));
  // Field JSArray::kElementsOffset is initialized later.
  __ sw(array_size, FieldMemOperand(result, JSArray::kLengthOffset));

  // Calculate the location of the elements array and set elements array member
  // of the JSArray.
  // result: JSObject
  // array_size: size of array (smi)
  __ Addu(elements_array_storage, result, Operand(JSArray::kSize));
  __ sw(elements_array_storage,
         FieldMemOperand(result, JSArray::kElementsOffset));

  // Clear the heap tag on the elements array.
  __ And(elements_array_storage,
          elements_array_storage,
          Operand(~kHeapObjectTagMask));
  // Initialize the fixed array and fill it with holes. FixedArray length is
  // stored as a smi.
  // result: JSObject
  // elements_array_storage: elements array (untagged)
  // array_size: size of array (smi)
  __ LoadRoot(scratch1, Heap::kFixedArrayMapRootIndex);
  ASSERT_EQ(0 * kPointerSize, FixedArray::kMapOffset);
  __ sw(scratch1, MemOperand(elements_array_storage));
  __ Addu(elements_array_storage, elements_array_storage, kPointerSize);

  // Length of the FixedArray is the number of pre-allocated elements if
  // the actual JSArray has length 0 and the size of the JSArray for non-empty
  // JSArrays. The length of a FixedArray is stored as a smi.
  ASSERT(kSmiTag == 0);
  __ li(at, Operand(Smi::FromInt(JSArray::kPreallocatedArrayElements)));
  __ movz(array_size, at, array_size);

  ASSERT_EQ(1 * kPointerSize, FixedArray::kLengthOffset);
  __ sw(array_size, MemOperand(elements_array_storage));
  __ Addu(elements_array_storage, elements_array_storage, kPointerSize);

  // Calculate elements array and elements array end.
  // result: JSObject
  // elements_array_storage: elements array element storage
  // array_size: smi-tagged size of elements array
  ASSERT(kSmiTag == 0 && kSmiTagSize < kPointerSizeLog2);
  __ sll(elements_array_end, array_size, kPointerSizeLog2 - kSmiTagSize);
  __ Addu(elements_array_end, elements_array_storage, elements_array_end);

  // Fill the allocated FixedArray with the hole value if requested.
  // result: JSObject
  // elements_array_storage: elements array element storage
  // elements_array_end: start of next object
  if (fill_with_hole) {
    Label loop, entry;
    __ LoadRoot(scratch1, Heap::kTheHoleValueRootIndex);
    __ Branch(&entry);
    __ bind(&loop);
    __ sw(scratch1, MemOperand(elements_array_storage));
    __ Addu(elements_array_storage, elements_array_storage, kPointerSize);

    __ bind(&entry);
    __ Branch(&loop, lt, elements_array_storage, Operand(elements_array_end));
  }
}


// Create a new array for the built-in Array function. This function allocates
// the JSArray object and the FixedArray elements array and initializes these.
// If the Array cannot be constructed in native code the runtime is called. This
// function assumes the following state:
//   a0: argc
//   a1: constructor (built-in Array function)
//   ra: return address
//   sp[0]: last argument
// This function is used for both construct and normal calls of Array. The only
// difference between handling a construct call and a normal call is that for a
// construct call the constructor function in a1 needs to be preserved for
// entering the generic code. In both cases argc in a0 needs to be preserved.
// Both registers are preserved by this code so no need to differentiate between
// construct call and normal call.
static void ArrayNativeCode(MacroAssembler* masm,
                            Label* call_generic_code) {
  Counters* counters = masm->isolate()->counters();
  Label argc_one_or_more, argc_two_or_more;

  // Check for array construction with zero arguments or one.
  __ Branch(&argc_one_or_more, ne, a0, Operand(zero_reg));
  // Handle construction of an empty array.
  AllocateEmptyJSArray(masm,
                       a1,
                       a2,
                       a3,
                       t0,
                       t1,
                       JSArray::kPreallocatedArrayElements,
                       call_generic_code);
  __ IncrementCounter(counters->array_function_native(), 1, a3, t0);
  // Setup return value, remove receiver from stack and return.
  __ mov(v0, a2);
  __ Addu(sp, sp, Operand(kPointerSize));
  __ Ret();

  // Check for one argument. Bail out if argument is not smi or if it is
  // negative.
  __ bind(&argc_one_or_more);
  __ Branch(&argc_two_or_more, ne, a0, Operand(1));

  ASSERT(kSmiTag == 0);
  __ lw(a2, MemOperand(sp));  // Get the argument from the stack.
  __ And(a3, a2, Operand(kIntptrSignBit | kSmiTagMask));
  __ Branch(call_generic_code, eq, a3, Operand(zero_reg));

  // Handle construction of an empty array of a certain size. Bail out if size
  // is too large to actually allocate an elements array.
  ASSERT(kSmiTag == 0);
  __ Branch(call_generic_code, Ugreater_equal, a2,
            Operand(JSObject::kInitialMaxFastElementArray << kSmiTagSize));

  // a0: argc
  // a1: constructor
  // a2: array_size (smi)
  // sp[0]: argument
  AllocateJSArray(masm,
                  a1,
                  a2,
                  a3,
                  t0,
                  t1,
                  t2,
                  t3,
                  true,
                  call_generic_code);
  __ IncrementCounter(counters->array_function_native(), 1, a2, t0);

  // Setup return value, remove receiver and argument from stack and return.
  __ mov(v0, a3);
  __ Addu(sp, sp, Operand(2 * kPointerSize));
  __ Ret();

  // Handle construction of an array from a list of arguments.
  __ bind(&argc_two_or_more);
  __ sll(a2, a0, kSmiTagSize);  // Convert argc to a smi.

  // a0: argc
  // a1: constructor
  // a2: array_size (smi)
  // sp[0]: last argument
  AllocateJSArray(masm,
                  a1,
                  a2,
                  a3,
                  t0,
                  t1,
                  t2,
                  t3,
                  false,
                  call_generic_code);
  __ IncrementCounter(counters->array_function_native(), 1, a2, t2);

  // Fill arguments as array elements. Copy from the top of the stack (last
  // element) to the array backing store filling it backwards. Note:
  // elements_array_end points after the backing store.
  // a0: argc
  // a3: JSArray
  // t0: elements_array storage start (untagged)
  // t1: elements_array_end (untagged)
  // sp[0]: last argument

  Label loop, entry;
  __ Branch(&entry);
  __ bind(&loop);
  __ pop(a2);
  __ Addu(t1, t1, -kPointerSize);
  __ sw(a2, MemOperand(t1));
  __ bind(&entry);
  __ Branch(&loop, lt, t0, Operand(t1));

  // Remove caller arguments and receiver from the stack, setup return value and
  // return.
  // a0: argc
  // a3: JSArray
  // sp[0]: receiver
  __ Addu(sp, sp, Operand(kPointerSize));
  __ mov(v0, a3);
  __ Ret();
}


void Builtins::Generate_ArrayCode(MacroAssembler* masm) {
  // ----------- S t a t e -------------
  //  -- a0     : number of arguments
  //  -- ra     : return address
  //  -- sp[...]: constructor arguments
  // -----------------------------------
  Label generic_array_code;

  // Get the Array function.
  GenerateLoadArrayFunction(masm, a1);

  if (FLAG_debug_code) {
    // Initial map for the builtin Array functions should be maps.
    __ lw(a2, FieldMemOperand(a1, JSFunction::kPrototypeOrInitialMapOffset));
    __ And(t0, a2, Operand(kSmiTagMask));
    __ Assert(ne, "Unexpected initial map for Array function (1)",
              t0, Operand(zero_reg));
    __ GetObjectType(a2, a3, t0);
    __ Assert(eq, "Unexpected initial map for Array function (2)",
              t0, Operand(MAP_TYPE));
  }

  // Run the native code for the Array function called as a normal function.
  ArrayNativeCode(masm, &generic_array_code);

  // Jump to the generic array code if the specialized code cannot handle
  // the construction.
  __ bind(&generic_array_code);

  Handle<Code> array_code =
      masm->isolate()->builtins()->ArrayCodeGeneric();
  __ Jump(array_code, RelocInfo::CODE_TARGET);
}


void Builtins::Generate_ArrayConstructCode(MacroAssembler* masm) {
  // ----------- S t a t e -------------
  //  -- a0     : number of arguments
  //  -- a1     : constructor function
  //  -- ra     : return address
  //  -- sp[...]: constructor arguments
  // -----------------------------------
  Label generic_constructor;

  if (FLAG_debug_code) {
    // The array construct code is only set for the builtin and internal
    // Array functions which always have a map.
    // Initial map for the builtin Array function should be a map.
    __ lw(a2, FieldMemOperand(a1, JSFunction::kPrototypeOrInitialMapOffset));
    __ And(t0, a2, Operand(kSmiTagMask));
    __ Assert(ne, "Unexpected initial map for Array function (3)",
              t0, Operand(zero_reg));
    __ GetObjectType(a2, a3, t0);
    __ Assert(eq, "Unexpected initial map for Array function (4)",
              t0, Operand(MAP_TYPE));
  }

  // Run the native code for the Array function called as a constructor.
  ArrayNativeCode(masm, &generic_constructor);

  // Jump to the generic construct code in case the specialized code cannot
  // handle the construction.
  __ bind(&generic_constructor);

  Handle<Code> generic_construct_stub =
      masm->isolate()->builtins()->JSConstructStubGeneric();
  __ Jump(generic_construct_stub, RelocInfo::CODE_TARGET);
}


void Builtins::Generate_StringConstructCode(MacroAssembler* masm) {
  // ----------- S t a t e -------------
  //  -- a0                     : number of arguments
  //  -- a1                     : constructor function
  //  -- ra                     : return address
  //  -- sp[(argc - n - 1) * 4] : arg[n] (zero based)
  //  -- sp[argc * 4]           : receiver
  // -----------------------------------
  Counters* counters = masm->isolate()->counters();
  __ IncrementCounter(counters->string_ctor_calls(), 1, a2, a3);

  Register function = a1;
  if (FLAG_debug_code) {
    __ LoadGlobalFunction(Context::STRING_FUNCTION_INDEX, a2);
    __ Assert(eq, "Unexpected String function", function, Operand(a2));
  }

  // Load the first arguments in a0 and get rid of the rest.
  Label no_arguments;
  __ Branch(&no_arguments, eq, a0, Operand(zero_reg));
  // First args = sp[(argc - 1) * 4].
  __ Subu(a0, a0, Operand(1));
  __ sll(a0, a0, kPointerSizeLog2);
  __ Addu(sp, a0, sp);
  __ lw(a0, MemOperand(sp));
  // sp now point to args[0], drop args[0] + receiver.
  __ Drop(2);

  Register argument = a2;
  Label not_cached, argument_is_string;
  NumberToStringStub::GenerateLookupNumberStringCache(
      masm,
      a0,        // Input.
      argument,  // Result.
      a3,        // Scratch.
      t0,        // Scratch.
      t1,        // Scratch.
      false,     // Is it a Smi?
      &not_cached);
  __ IncrementCounter(counters->string_ctor_cached_number(), 1, a3, t0);
  __ bind(&argument_is_string);

  // ----------- S t a t e -------------
  //  -- a2     : argument converted to string
  //  -- a1     : constructor function
  //  -- ra     : return address
  // -----------------------------------

  Label gc_required;
  __ AllocateInNewSpace(JSValue::kSize,
                        v0,  // Result.
                        a3,  // Scratch.
                        t0,  // Scratch.
                        &gc_required,
                        TAG_OBJECT);

  // Initialising the String Object.
  Register map = a3;
  __ LoadGlobalFunctionInitialMap(function, map, t0);
  if (FLAG_debug_code) {
    __ lbu(t0, FieldMemOperand(map, Map::kInstanceSizeOffset));
    __ Assert(eq, "Unexpected string wrapper instance size",
        t0, Operand(JSValue::kSize >> kPointerSizeLog2));
    __ lbu(t0, FieldMemOperand(map, Map::kUnusedPropertyFieldsOffset));
    __ Assert(eq, "Unexpected unused properties of string wrapper",
        t0, Operand(zero_reg));
  }
  __ sw(map, FieldMemOperand(v0, HeapObject::kMapOffset));

  __ LoadRoot(a3, Heap::kEmptyFixedArrayRootIndex);
  __ sw(a3, FieldMemOperand(v0, JSObject::kPropertiesOffset));
  __ sw(a3, FieldMemOperand(v0, JSObject::kElementsOffset));

  __ sw(argument, FieldMemOperand(v0, JSValue::kValueOffset));

  // Ensure the object is fully initialized.
  STATIC_ASSERT(JSValue::kSize == 4 * kPointerSize);

  __ Ret();

  // The argument was not found in the number to string cache. Check
  // if it's a string already before calling the conversion builtin.
  Label convert_argument;
  __ bind(&not_cached);
  __ JumpIfSmi(a0, &convert_argument);

  // Is it a String?
  __ lw(a2, FieldMemOperand(a0, HeapObject::kMapOffset));
  __ lbu(a3, FieldMemOperand(a2, Map::kInstanceTypeOffset));
  ASSERT(kNotStringTag != 0);
  __ And(t0, a3, Operand(kIsNotStringMask));
  __ Branch(&convert_argument, ne, t0, Operand(zero_reg));
  __ mov(argument, a0);
  __ IncrementCounter(counters->string_ctor_conversions(), 1, a3, t0);
  __ Branch(&argument_is_string);

  // Invoke the conversion builtin and put the result into a2.
  __ bind(&convert_argument);
  __ push(function);  // Preserve the function.
  __ IncrementCounter(counters->string_ctor_conversions(), 1, a3, t0);
  __ EnterInternalFrame();
  __ push(v0);
  __ InvokeBuiltin(Builtins::TO_STRING, CALL_FUNCTION);
  __ LeaveInternalFrame();
  __ pop(function);
  __ mov(argument, v0);
  __ Branch(&argument_is_string);

  // Load the empty string into a2, remove the receiver from the
  // stack, and jump back to the case where the argument is a string.
  __ bind(&no_arguments);
  __ LoadRoot(argument, Heap::kEmptyStringRootIndex);
  __ Drop(1);
  __ Branch(&argument_is_string);

  // At this point the argument is already a string. Call runtime to
  // create a string wrapper.
  __ bind(&gc_required);
  __ IncrementCounter(counters->string_ctor_gc_required(), 1, a3, t0);
  __ EnterInternalFrame();
  __ push(argument);
  __ CallRuntime(Runtime::kNewStringWrapper, 1);
  __ LeaveInternalFrame();
  __ Ret();
}


void Builtins::Generate_JSConstructCall(MacroAssembler* masm) {
  // ----------- S t a t e -------------
  //  -- a0     : number of arguments
  //  -- a1     : constructor function
  //  -- ra     : return address
  //  -- sp[...]: constructor arguments
  // -----------------------------------

  Label non_function_call;
  // Check that the function is not a smi.
  __ And(t0, a1, Operand(kSmiTagMask));
  __ Branch(&non_function_call, eq, t0, Operand(zero_reg));
  // Check that the function is a JSFunction.
  __ GetObjectType(a1, a2, a2);
  __ Branch(&non_function_call, ne, a2, Operand(JS_FUNCTION_TYPE));

  // Jump to the function-specific construct stub.
  __ lw(a2, FieldMemOperand(a1, JSFunction::kSharedFunctionInfoOffset));
  __ lw(a2, FieldMemOperand(a2, SharedFunctionInfo::kConstructStubOffset));
  __ Addu(t9, a2, Operand(Code::kHeaderSize - kHeapObjectTag));
  __ Jump(t9);

  // a0: number of arguments
  // a1: called object
  __ bind(&non_function_call);
  // CALL_NON_FUNCTION expects the non-function constructor as receiver
  // (instead of the original receiver from the call site). The receiver is
  // stack element argc.
  // Set expected number of arguments to zero (not changing a0).
  __ mov(a2, zero_reg);
  __ GetBuiltinEntry(a3, Builtins::CALL_NON_FUNCTION_AS_CONSTRUCTOR);
  __ SetCallKind(t1, CALL_AS_METHOD);
  __ Jump(masm->isolate()->builtins()->ArgumentsAdaptorTrampoline(),
          RelocInfo::CODE_TARGET);
}


static void Generate_JSConstructStubHelper(MacroAssembler* masm,
                                           bool is_api_function,
                                           bool count_constructions) {
  // Should never count constructions for api objects.
  ASSERT(!is_api_function || !count_constructions);

  Isolate* isolate = masm->isolate();

  // ----------- S t a t e -------------
  //  -- a0     : number of arguments
  //  -- a1     : constructor function
  //  -- ra     : return address
  //  -- sp[...]: constructor arguments
  // -----------------------------------

  // Enter a construct frame.
  __ EnterConstructFrame();

  // Preserve the two incoming parameters on the stack.
  __ sll(a0, a0, kSmiTagSize);  // Tag arguments count.
  __ MultiPushReversed(a0.bit() | a1.bit());

  // Use t7 to hold undefined, which is used in several places below.
  __ LoadRoot(t7, Heap::kUndefinedValueRootIndex);

  Label rt_call, allocated;
  // Try to allocate the object without transitioning into C code. If any of the
  // preconditions is not met, the code bails out to the runtime call.
  if (FLAG_inline_new) {
    Label undo_allocation;
#ifdef ENABLE_DEBUGGER_SUPPORT
    ExternalReference debug_step_in_fp =
        ExternalReference::debug_step_in_fp_address(isolate);
    __ li(a2, Operand(debug_step_in_fp));
    __ lw(a2, MemOperand(a2));
    __ Branch(&rt_call, ne, a2, Operand(zero_reg));
#endif

    // Load the initial map and verify that it is in fact a map.
    // a1: constructor function
    __ lw(a2, FieldMemOperand(a1, JSFunction::kPrototypeOrInitialMapOffset));
    __ And(t0, a2, Operand(kSmiTagMask));
    __ Branch(&rt_call, eq, t0, Operand(zero_reg));
    __ GetObjectType(a2, a3, t4);
    __ Branch(&rt_call, ne, t4, Operand(MAP_TYPE));

    // Check that the constructor is not constructing a JSFunction (see comments
    // in Runtime_NewObject in runtime.cc). In which case the initial map's
    // instance type would be JS_FUNCTION_TYPE.
    // a1: constructor function
    // a2: initial map
    __ lbu(a3, FieldMemOperand(a2, Map::kInstanceTypeOffset));
    __ Branch(&rt_call, eq, a3, Operand(JS_FUNCTION_TYPE));

    if (count_constructions) {
      Label allocate;
      // Decrease generous allocation count.
      __ lw(a3, FieldMemOperand(a1, JSFunction::kSharedFunctionInfoOffset));
      MemOperand constructor_count =
         FieldMemOperand(a3, SharedFunctionInfo::kConstructionCountOffset);
      __ lbu(t0, constructor_count);
      __ Subu(t0, t0, Operand(1));
      __ sb(t0, constructor_count);
      __ Branch(&allocate, ne, t0, Operand(zero_reg));

      __ Push(a1, a2);

      __ push(a1);  // Constructor.
      // The call will replace the stub, so the countdown is only done once.
      __ CallRuntime(Runtime::kFinalizeInstanceSize, 1);

      __ pop(a2);
      __ pop(a1);

      __ bind(&allocate);
    }

    // Now allocate the JSObject on the heap.
    // a1: constructor function
    // a2: initial map
    __ lbu(a3, FieldMemOperand(a2, Map::kInstanceSizeOffset));
    __ AllocateInNewSpace(a3, t4, t5, t6, &rt_call, SIZE_IN_WORDS);

    // Allocated the JSObject, now initialize the fields. Map is set to initial
    // map and properties and elements are set to empty fixed array.
    // a1: constructor function
    // a2: initial map
    // a3: object size
    // t4: JSObject (not tagged)
    __ LoadRoot(t6, Heap::kEmptyFixedArrayRootIndex);
    __ mov(t5, t4);
    __ sw(a2, MemOperand(t5, JSObject::kMapOffset));
    __ sw(t6, MemOperand(t5, JSObject::kPropertiesOffset));
    __ sw(t6, MemOperand(t5, JSObject::kElementsOffset));
    __ Addu(t5, t5, Operand(3*kPointerSize));
    ASSERT_EQ(0 * kPointerSize, JSObject::kMapOffset);
    ASSERT_EQ(1 * kPointerSize, JSObject::kPropertiesOffset);
    ASSERT_EQ(2 * kPointerSize, JSObject::kElementsOffset);

    // Fill all the in-object properties with appropriate filler.
    // a1: constructor function
    // a2: initial map
    // a3: object size (in words)
    // t4: JSObject (not tagged)
    // t5: First in-object property of JSObject (not tagged)
    __ sll(t0, a3, kPointerSizeLog2);
    __ addu(t6, t4, t0);   // End of object.
    ASSERT_EQ(3 * kPointerSize, JSObject::kHeaderSize);
    { Label loop, entry;
      if (count_constructions) {
        // To allow for truncation.
        __ LoadRoot(t7, Heap::kOnePointerFillerMapRootIndex);
      } else {
        __ LoadRoot(t7, Heap::kUndefinedValueRootIndex);
      }
      __ jmp(&entry);
      __ bind(&loop);
      __ sw(t7, MemOperand(t5, 0));
      __ addiu(t5, t5, kPointerSize);
      __ bind(&entry);
      __ Branch(&loop, Uless, t5, Operand(t6));
    }

    // Add the object tag to make the JSObject real, so that we can continue and
    // jump into the continuation code at any time from now on. Any failures
    // need to undo the allocation, so that the heap is in a consistent state
    // and verifiable.
    __ Addu(t4, t4, Operand(kHeapObjectTag));

    // Check if a non-empty properties array is needed. Continue with allocated
    // object if not fall through to runtime call if it is.
    // a1: constructor function
    // t4: JSObject
    // t5: start of next object (not tagged)
    __ lbu(a3, FieldMemOperand(a2, Map::kUnusedPropertyFieldsOffset));
    // The field instance sizes contains both pre-allocated property fields and
    // in-object properties.
    __ lw(a0, FieldMemOperand(a2, Map::kInstanceSizesOffset));
    __ And(t6,
           a0,
           Operand(0x000000FF << Map::kPreAllocatedPropertyFieldsByte * 8));
    __ srl(t0, t6, Map::kPreAllocatedPropertyFieldsByte * 8);
    __ Addu(a3, a3, Operand(t0));
    __ And(t6, a0, Operand(0x000000FF << Map::kInObjectPropertiesByte * 8));
    __ srl(t0, t6, Map::kInObjectPropertiesByte * 8);
    __ subu(a3, a3, t0);

    // Done if no extra properties are to be allocated.
    __ Branch(&allocated, eq, a3, Operand(zero_reg));
    __ Assert(greater_equal, "Property allocation count failed.",
        a3, Operand(zero_reg));

    // Scale the number of elements by pointer size and add the header for
    // FixedArrays to the start of the next object calculation from above.
    // a1: constructor
    // a3: number of elements in properties array
    // t4: JSObject
    // t5: start of next object
    __ Addu(a0, a3, Operand(FixedArray::kHeaderSize / kPointerSize));
    __ AllocateInNewSpace(
        a0,
        t5,
        t6,
        a2,
        &undo_allocation,
        static_cast<AllocationFlags>(RESULT_CONTAINS_TOP | SIZE_IN_WORDS));

    // Initialize the FixedArray.
    // a1: constructor
    // a3: number of elements in properties array (un-tagged)
    // t4: JSObject
    // t5: start of next object
    __ LoadRoot(t6, Heap::kFixedArrayMapRootIndex);
    __ mov(a2, t5);
    __ sw(t6, MemOperand(a2, JSObject::kMapOffset));
    __ sll(a0, a3, kSmiTagSize);
    __ sw(a0, MemOperand(a2, FixedArray::kLengthOffset));
    __ Addu(a2, a2, Operand(2 * kPointerSize));

    ASSERT_EQ(0 * kPointerSize, JSObject::kMapOffset);
    ASSERT_EQ(1 * kPointerSize, FixedArray::kLengthOffset);

    // Initialize the fields to undefined.
    // a1: constructor
    // a2: First element of FixedArray (not tagged)
    // a3: number of elements in properties array
    // t4: JSObject
    // t5: FixedArray (not tagged)
    __ sll(t3, a3, kPointerSizeLog2);
    __ addu(t6, a2, t3);  // End of object.
    ASSERT_EQ(2 * kPointerSize, FixedArray::kHeaderSize);
    { Label loop, entry;
      if (count_constructions) {
        __ LoadRoot(t7, Heap::kUndefinedValueRootIndex);
      } else if (FLAG_debug_code) {
        __ LoadRoot(t8, Heap::kUndefinedValueRootIndex);
        __ Assert(eq, "Undefined value not loaded.", t7, Operand(t8));
      }
      __ jmp(&entry);
      __ bind(&loop);
      __ sw(t7, MemOperand(a2));
      __ addiu(a2, a2, kPointerSize);
      __ bind(&entry);
      __ Branch(&loop, less, a2, Operand(t6));
    }

    // Store the initialized FixedArray into the properties field of
    // the JSObject.
    // a1: constructor function
    // t4: JSObject
    // t5: FixedArray (not tagged)
    __ Addu(t5, t5, Operand(kHeapObjectTag));  // Add the heap tag.
    __ sw(t5, FieldMemOperand(t4, JSObject::kPropertiesOffset));

    // Continue with JSObject being successfully allocated.
    // a1: constructor function
    // a4: JSObject
    __ jmp(&allocated);

    // Undo the setting of the new top so that the heap is verifiable. For
    // example, the map's unused properties potentially do not match the
    // allocated objects unused properties.
    // t4: JSObject (previous new top)
    __ bind(&undo_allocation);
    __ UndoAllocationInNewSpace(t4, t5);
  }

  __ bind(&rt_call);
  // Allocate the new receiver object using the runtime call.
  // a1: constructor function
  __ push(a1);  // Argument for Runtime_NewObject.
  __ CallRuntime(Runtime::kNewObject, 1);
  __ mov(t4, v0);

  // Receiver for constructor call allocated.
  // t4: JSObject
  __ bind(&allocated);
  __ push(t4);

  // Push the function and the allocated receiver from the stack.
  // sp[0]: receiver (newly allocated object)
  // sp[1]: constructor function
  // sp[2]: number of arguments (smi-tagged)
  __ lw(a1, MemOperand(sp, kPointerSize));
  __ MultiPushReversed(a1.bit() | t4.bit());

  // Reload the number of arguments from the stack.
  // a1: constructor function
  // sp[0]: receiver
  // sp[1]: constructor function
  // sp[2]: receiver
  // sp[3]: constructor function
  // sp[4]: number of arguments (smi-tagged)
  __ lw(a3, MemOperand(sp, 4 * kPointerSize));

  // Setup pointer to last argument.
  __ Addu(a2, fp, Operand(StandardFrameConstants::kCallerSPOffset));

  // Setup number of arguments for function call below.
  __ srl(a0, a3, kSmiTagSize);

  // Copy arguments and receiver to the expression stack.
  // a0: number of arguments
  // a1: constructor function
  // a2: address of last argument (caller sp)
  // a3: number of arguments (smi-tagged)
  // sp[0]: receiver
  // sp[1]: constructor function
  // sp[2]: receiver
  // sp[3]: constructor function
  // sp[4]: number of arguments (smi-tagged)
  Label loop, entry;
  __ jmp(&entry);
  __ bind(&loop);
  __ sll(t0, a3, kPointerSizeLog2 - kSmiTagSize);
  __ Addu(t0, a2, Operand(t0));
  __ lw(t1, MemOperand(t0));
  __ push(t1);
  __ bind(&entry);
  __ Addu(a3, a3, Operand(-2));
  __ Branch(&loop, greater_equal, a3, Operand(zero_reg));

  // Call the function.
  // a0: number of arguments
  // a1: constructor function
  if (is_api_function) {
    __ lw(cp, FieldMemOperand(a1, JSFunction::kContextOffset));
    Handle<Code> code =
        masm->isolate()->builtins()->HandleApiCallConstruct();
    ParameterCount expected(0);
    __ InvokeCode(code, expected, expected,
                  RelocInfo::CODE_TARGET, CALL_FUNCTION, CALL_AS_METHOD);
  } else {
    ParameterCount actual(a0);
    __ InvokeFunction(a1, actual, CALL_FUNCTION,
                      NullCallWrapper(), CALL_AS_METHOD);
  }

  // Pop the function from the stack.
  // v0: result
  // sp[0]: constructor function
  // sp[2]: receiver
  // sp[3]: constructor function
  // sp[4]: number of arguments (smi-tagged)
  __ Pop();

  // Restore context from the frame.
  __ lw(cp, MemOperand(fp, StandardFrameConstants::kContextOffset));

  // If the result is an object (in the ECMA sense), we should get rid
  // of the receiver and use the result; see ECMA-262 section 13.2.2-7
  // on page 74.
  Label use_receiver, exit;

  // If the result is a smi, it is *not* an object in the ECMA sense.
  // v0: result
  // sp[0]: receiver (newly allocated object)
  // sp[1]: constructor function
  // sp[2]: number of arguments (smi-tagged)
  __ And(t0, v0, Operand(kSmiTagMask));
  __ Branch(&use_receiver, eq, t0, Operand(zero_reg));

  // If the type of the result (stored in its map) is less than
  // FIRST_SPEC_OBJECT_TYPE, it is not an object in the ECMA sense.
  __ GetObjectType(v0, a3, a3);
  __ Branch(&exit, greater_equal, a3, Operand(FIRST_SPEC_OBJECT_TYPE));

  // Throw away the result of the constructor invocation and use the
  // on-stack receiver as the result.
  __ bind(&use_receiver);
  __ lw(v0, MemOperand(sp));

  // Remove receiver from the stack, remove caller arguments, and
  // return.
  __ bind(&exit);
  // v0: result
  // sp[0]: receiver (newly allocated object)
  // sp[1]: constructor function
  // sp[2]: number of arguments (smi-tagged)
  __ lw(a1, MemOperand(sp, 2 * kPointerSize));
  __ LeaveConstructFrame();
  __ sll(t0, a1, kPointerSizeLog2 - 1);
  __ Addu(sp, sp, t0);
  __ Addu(sp, sp, kPointerSize);
  __ IncrementCounter(isolate->counters()->constructed_objects(), 1, a1, a2);
  __ Ret();
}


void Builtins::Generate_JSConstructStubCountdown(MacroAssembler* masm) {
  Generate_JSConstructStubHelper(masm, false, true);
}


void Builtins::Generate_JSConstructStubGeneric(MacroAssembler* masm) {
  Generate_JSConstructStubHelper(masm, false, false);
}


void Builtins::Generate_JSConstructStubApi(MacroAssembler* masm) {
  Generate_JSConstructStubHelper(masm, true, false);
}


static void Generate_JSEntryTrampolineHelper(MacroAssembler* masm,
                                             bool is_construct) {
  // Called from JSEntryStub::GenerateBody

  // ----------- S t a t e -------------
  //  -- a0: code entry
  //  -- a1: function
  //  -- a2: reveiver_pointer
  //  -- a3: argc
  //  -- s0: argv
  // -----------------------------------

  // Clear the context before we push it when entering the JS frame.
  __ mov(cp, zero_reg);

  // Enter an internal frame.
  __ EnterInternalFrame();

  // Set up the context from the function argument.
  __ lw(cp, FieldMemOperand(a1, JSFunction::kContextOffset));

  // Set up the roots register.
  ExternalReference roots_address =
      ExternalReference::roots_address(masm->isolate());
  __ li(s6, Operand(roots_address));

  // Push the function and the receiver onto the stack.
  __ Push(a1, a2);

  // Copy arguments to the stack in a loop.
  // a3: argc
  // s0: argv, ie points to first arg
  Label loop, entry;
  __ sll(t0, a3, kPointerSizeLog2);
  __ addu(t2, s0, t0);
  __ b(&entry);
  __ nop();   // Branch delay slot nop.
  // t2 points past last arg.
  __ bind(&loop);
  __ lw(t0, MemOperand(s0));  // Read next parameter.
  __ addiu(s0, s0, kPointerSize);
  __ lw(t0, MemOperand(t0));  // Dereference handle.
  __ push(t0);  // Push parameter.
  __ bind(&entry);
  __ Branch(&loop, ne, s0, Operand(t2));

  // Initialize all JavaScript callee-saved registers, since they will be seen
  // by the garbage collector as part of handlers.
  __ LoadRoot(t0, Heap::kUndefinedValueRootIndex);
  __ mov(s1, t0);
  __ mov(s2, t0);
  __ mov(s3, t0);
  __ mov(s4, t0);
  __ mov(s5, t0);
  // s6 holds the root address. Do not clobber.
  // s7 is cp. Do not init.

  // Invoke the code and pass argc as a0.
  __ mov(a0, a3);
  if (is_construct) {
    __ Call(masm->isolate()->builtins()->JSConstructCall());
  } else {
    ParameterCount actual(a0);
    __ InvokeFunction(a1, actual, CALL_FUNCTION,
                      NullCallWrapper(), CALL_AS_METHOD);
  }

  __ LeaveInternalFrame();

  __ Jump(ra);
}


void Builtins::Generate_JSEntryTrampoline(MacroAssembler* masm) {
  Generate_JSEntryTrampolineHelper(masm, false);
}


void Builtins::Generate_JSConstructEntryTrampoline(MacroAssembler* masm) {
  Generate_JSEntryTrampolineHelper(masm, true);
}


void Builtins::Generate_LazyCompile(MacroAssembler* masm) {
  // Enter an internal frame.
  __ EnterInternalFrame();

  // Preserve the function.
  __ push(a1);
  // Push call kind information.
  __ push(t1);

  // Push the function on the stack as the argument to the runtime function.
  __ push(a1);
  // Call the runtime function.
  __ CallRuntime(Runtime::kLazyCompile, 1);
  // Calculate the entry point.
  __ addiu(t9, v0, Code::kHeaderSize - kHeapObjectTag);

  // Restore call kind information.
  __ pop(t1);
  // Restore saved function.
  __ pop(a1);

  // Tear down temporary frame.
  __ LeaveInternalFrame();

  // Do a tail-call of the compiled function.
  __ Jump(t9);
}


void Builtins::Generate_LazyRecompile(MacroAssembler* masm) {
  // Enter an internal frame.
  __ EnterInternalFrame();

  // Preserve the function.
  __ push(a1);
  // Push call kind information.
  __ push(t1);

  // Push the function on the stack as the argument to the runtime function.
  __ push(a1);
  __ CallRuntime(Runtime::kLazyRecompile, 1);
  // Calculate the entry point.
  __ Addu(t9, v0, Operand(Code::kHeaderSize - kHeapObjectTag));

  // Restore call kind information.
  __ pop(t1);
  // Restore saved function.
  __ pop(a1);

  // Tear down temporary frame.
  __ LeaveInternalFrame();

  // Do a tail-call of the compiled function.
  __ Jump(t9);
}


// These functions are called from C++ but cannot be used in live code.
void Builtins::Generate_NotifyDeoptimized(MacroAssembler* masm) {
  __ Abort("Call to unimplemented function in builtins-mips.cc");
}


void Builtins::Generate_NotifyLazyDeoptimized(MacroAssembler* masm) {
  __ Abort("Call to unimplemented function in builtins-mips.cc");
}


void Builtins::Generate_NotifyOSR(MacroAssembler* masm) {
  __ Abort("Call to unimplemented function in builtins-mips.cc");
}


void Builtins::Generate_OnStackReplacement(MacroAssembler* masm) {
  __ Abort("Call to unimplemented function in builtins-mips.cc");
}


void Builtins::Generate_FunctionCall(MacroAssembler* masm) {
  // 1. Make sure we have at least one argument.
  // a0: actual number of arguments
  { Label done;
    __ Branch(&done, ne, a0, Operand(zero_reg));
    __ LoadRoot(t2, Heap::kUndefinedValueRootIndex);
    __ push(t2);
    __ Addu(a0, a0, Operand(1));
    __ bind(&done);
  }

  // 2. Get the function to call (passed as receiver) from the stack, check
  //    if it is a function.
  // a0: actual number of arguments
  Label non_function;
  __ sll(at, a0, kPointerSizeLog2);
  __ addu(at, sp, at);
  __ lw(a1, MemOperand(at));
  __ And(at, a1, Operand(kSmiTagMask));
  __ Branch(&non_function, eq, at, Operand(zero_reg));
  __ GetObjectType(a1, a2, a2);
  __ Branch(&non_function, ne, a2, Operand(JS_FUNCTION_TYPE));

  // 3a. Patch the first argument if necessary when calling a function.
  // a0: actual number of arguments
  // a1: function
  Label shift_arguments;
  { Label convert_to_object, use_global_receiver, patch_receiver;
    // Change context eagerly in case we need the global receiver.
    __ lw(cp, FieldMemOperand(a1, JSFunction::kContextOffset));

    // Do not transform the receiver for strict mode functions.
    __ lw(a2, FieldMemOperand(a1, JSFunction::kSharedFunctionInfoOffset));
    __ lw(a3, FieldMemOperand(a2, SharedFunctionInfo::kCompilerHintsOffset));
    __ And(t0, a3, Operand(1 << (SharedFunctionInfo::kStrictModeFunction +
                                 kSmiTagSize)));
    __ Branch(&shift_arguments, ne, t0, Operand(zero_reg));

    // Do not transform the receiver for native (Compilerhints already in a3).
    __ And(t0, a3, Operand(1 << (SharedFunctionInfo::kNative + kSmiTagSize)));
    __ Branch(&shift_arguments, ne, t0, Operand(zero_reg));

    // Compute the receiver in non-strict mode.
    // Load first argument in a2. a2 = -kPointerSize(sp + n_args << 2).
    __ sll(at, a0, kPointerSizeLog2);
    __ addu(a2, sp, at);
    __ lw(a2, MemOperand(a2, -kPointerSize));
    // a0: actual number of arguments
    // a1: function
    // a2: first argument
    __ JumpIfSmi(a2, &convert_to_object, t2);

    __ LoadRoot(a3, Heap::kUndefinedValueRootIndex);
    __ Branch(&use_global_receiver, eq, a2, Operand(a3));
    __ LoadRoot(a3, Heap::kNullValueRootIndex);
    __ Branch(&use_global_receiver, eq, a2, Operand(a3));

    STATIC_ASSERT(LAST_SPEC_OBJECT_TYPE == LAST_TYPE);
    __ GetObjectType(a2, a3, a3);
    __ Branch(&shift_arguments, ge, a3, Operand(FIRST_SPEC_OBJECT_TYPE));

    __ bind(&convert_to_object);
    __ EnterInternalFrame();  // In order to preserve argument count.
    __ sll(a0, a0, kSmiTagSize);  // Smi tagged.
    __ push(a0);

    __ push(a2);
    __ InvokeBuiltin(Builtins::TO_OBJECT, CALL_FUNCTION);
    __ mov(a2, v0);

    __ pop(a0);
    __ sra(a0, a0, kSmiTagSize);  // Un-tag.
    __ LeaveInternalFrame();
    // Restore the function to a1.
    __ sll(at, a0, kPointerSizeLog2);
    __ addu(at, sp, at);
    __ lw(a1, MemOperand(at));
    __ Branch(&patch_receiver);

    // Use the global receiver object from the called function as the
    // receiver.
    __ bind(&use_global_receiver);
    const int kGlobalIndex =
        Context::kHeaderSize + Context::GLOBAL_INDEX * kPointerSize;
    __ lw(a2, FieldMemOperand(cp, kGlobalIndex));
    __ lw(a2, FieldMemOperand(a2, GlobalObject::kGlobalContextOffset));
    __ lw(a2, FieldMemOperand(a2, kGlobalIndex));
    __ lw(a2, FieldMemOperand(a2, GlobalObject::kGlobalReceiverOffset));

    __ bind(&patch_receiver);
    __ sll(at, a0, kPointerSizeLog2);
    __ addu(a3, sp, at);
    __ sw(a2, MemOperand(a3, -kPointerSize));

    __ Branch(&shift_arguments);
  }

  // 3b. Patch the first argument when calling a non-function.  The
  //     CALL_NON_FUNCTION builtin expects the non-function callee as
  //     receiver, so overwrite the first argument which will ultimately
  //     become the receiver.
  // a0: actual number of arguments
  // a1: function
  __ bind(&non_function);
  // Restore the function in case it has been modified.
  __ sll(at, a0, kPointerSizeLog2);
  __ addu(a2, sp, at);
  __ sw(a1, MemOperand(a2, -kPointerSize));
  // Clear a1 to indicate a non-function being called.
  __ mov(a1, zero_reg);

  // 4. Shift arguments and return address one slot down on the stack
  //    (overwriting the original receiver).  Adjust argument count to make
  //    the original first argument the new receiver.
  // a0: actual number of arguments
  // a1: function
  __ bind(&shift_arguments);
  { Label loop;
    // Calculate the copy start address (destination). Copy end address is sp.
    __ sll(at, a0, kPointerSizeLog2);
    __ addu(a2, sp, at);

    __ bind(&loop);
    __ lw(at, MemOperand(a2, -kPointerSize));
    __ sw(at, MemOperand(a2));
    __ Subu(a2, a2, Operand(kPointerSize));
    __ Branch(&loop, ne, a2, Operand(sp));
    // Adjust the actual number of arguments and remove the top element
    // (which is a copy of the last argument).
    __ Subu(a0, a0, Operand(1));
    __ Pop();
  }

  // 5a. Call non-function via tail call to CALL_NON_FUNCTION builtin.
  // a0: actual number of arguments
  // a1: function
  { Label function;
    __ Branch(&function, ne, a1, Operand(zero_reg));
    __ mov(a2, zero_reg);  // expected arguments is 0 for CALL_NON_FUNCTION
    __ GetBuiltinEntry(a3, Builtins::CALL_NON_FUNCTION);
    __ SetCallKind(t1, CALL_AS_METHOD);
    __ Jump(masm->isolate()->builtins()->ArgumentsAdaptorTrampoline(),
            RelocInfo::CODE_TARGET);
    __ bind(&function);
  }

  // 5b. Get the code to call from the function and check that the number of
  //     expected arguments matches what we're providing.  If so, jump
  //     (tail-call) to the code in register edx without checking arguments.
  // a0: actual number of arguments
  // a1: function
  __ lw(a3, FieldMemOperand(a1, JSFunction::kSharedFunctionInfoOffset));
  __ lw(a2,
         FieldMemOperand(a3, SharedFunctionInfo::kFormalParameterCountOffset));
  __ sra(a2, a2, kSmiTagSize);
  __ lw(a3, FieldMemOperand(a1, JSFunction::kCodeEntryOffset));
  __ SetCallKind(t1, CALL_AS_METHOD);
  // Check formal and actual parameter counts.
  __ Jump(masm->isolate()->builtins()->ArgumentsAdaptorTrampoline(),
          RelocInfo::CODE_TARGET, ne, a2, Operand(a0));

  ParameterCount expected(0);
  __ InvokeCode(a3, expected, expected, JUMP_FUNCTION,
                NullCallWrapper(), CALL_AS_METHOD);
}


void Builtins::Generate_FunctionApply(MacroAssembler* masm) {
  const int kIndexOffset    = -5 * kPointerSize;
  const int kLimitOffset    = -4 * kPointerSize;
  const int kArgsOffset     =  2 * kPointerSize;
  const int kRecvOffset     =  3 * kPointerSize;
  const int kFunctionOffset =  4 * kPointerSize;

  __ EnterInternalFrame();

  __ lw(a0, MemOperand(fp, kFunctionOffset));  // Get the function.
  __ push(a0);
  __ lw(a0, MemOperand(fp, kArgsOffset));  // Get the args array.
  __ push(a0);
  // Returns (in v0) number of arguments to copy to stack as Smi.
  __ InvokeBuiltin(Builtins::APPLY_PREPARE, CALL_FUNCTION);

  // Check the stack for overflow. We are not trying need to catch
  // interruptions (e.g. debug break and preemption) here, so the "real stack
  // limit" is checked.
  Label okay;
  __ LoadRoot(a2, Heap::kRealStackLimitRootIndex);
  // Make a2 the space we have left. The stack might already be overflowed
  // here which will cause a2 to become negative.
  __ subu(a2, sp, a2);
  // Check if the arguments will overflow the stack.
  __ sll(t0, v0, kPointerSizeLog2 - kSmiTagSize);
  __ Branch(&okay, gt, a2, Operand(t0));  // Signed comparison.

  // Out of stack space.
  __ lw(a1, MemOperand(fp, kFunctionOffset));
  __ push(a1);
  __ push(v0);
  __ InvokeBuiltin(Builtins::APPLY_OVERFLOW, CALL_FUNCTION);
  // End of stack check.

  // Push current limit and index.
  __ bind(&okay);
  __ push(v0);  // Limit.
  __ mov(a1, zero_reg);  // Initial index.
  __ push(a1);

  // Change context eagerly to get the right global object if necessary.
  __ lw(a0, MemOperand(fp, kFunctionOffset));
  __ lw(cp, FieldMemOperand(a0, JSFunction::kContextOffset));
  // Load the shared function info while the function is still in a0.
  __ lw(a1, FieldMemOperand(a0, JSFunction::kSharedFunctionInfoOffset));

  // Compute the receiver.
  Label call_to_object, use_global_receiver, push_receiver;
  __ lw(a0, MemOperand(fp, kRecvOffset));

  // Do not transform the receiver for strict mode functions.
  __ lw(a2, FieldMemOperand(a1, SharedFunctionInfo::kCompilerHintsOffset));
  __ And(t0, a2, Operand(1 << (SharedFunctionInfo::kStrictModeFunction +
                               kSmiTagSize)));
  __ Branch(&push_receiver, ne, t0, Operand(zero_reg));

  // Do not transform the receiver for native (Compilerhints already in a2).
  __ And(t0, a2, Operand(1 << (SharedFunctionInfo::kNative + kSmiTagSize)));
  __ Branch(&push_receiver, ne, t0, Operand(zero_reg));

  // Compute the receiver in non-strict mode.
  __ And(t0, a0, Operand(kSmiTagMask));
  __ Branch(&call_to_object, eq, t0, Operand(zero_reg));
  __ LoadRoot(a1, Heap::kNullValueRootIndex);
  __ Branch(&use_global_receiver, eq, a0, Operand(a1));
  __ LoadRoot(a2, Heap::kUndefinedValueRootIndex);
  __ Branch(&use_global_receiver, eq, a0, Operand(a2));

  // Check if the receiver is already a JavaScript object.
  // a0: receiver
  STATIC_ASSERT(LAST_SPEC_OBJECT_TYPE == LAST_TYPE);
  __ GetObjectType(a0, a1, a1);
  __ Branch(&push_receiver, ge, a1, Operand(FIRST_SPEC_OBJECT_TYPE));

  // Convert the receiver to a regular object.
  // a0: receiver
  __ bind(&call_to_object);
  __ push(a0);
  __ InvokeBuiltin(Builtins::TO_OBJECT, CALL_FUNCTION);
  __ mov(a0, v0);  // Put object in a0 to match other paths to push_receiver.
  __ Branch(&push_receiver);

  // Use the current global receiver object as the receiver.
  __ bind(&use_global_receiver);
  const int kGlobalOffset =
      Context::kHeaderSize + Context::GLOBAL_INDEX * kPointerSize;
  __ lw(a0, FieldMemOperand(cp, kGlobalOffset));
  __ lw(a0, FieldMemOperand(a0, GlobalObject::kGlobalContextOffset));
  __ lw(a0, FieldMemOperand(a0, kGlobalOffset));
  __ lw(a0, FieldMemOperand(a0, GlobalObject::kGlobalReceiverOffset));

  // Push the receiver.
  // a0: receiver
  __ bind(&push_receiver);
  __ push(a0);

  // Copy all arguments from the array to the stack.
  Label entry, loop;
  __ lw(a0, MemOperand(fp, kIndexOffset));
  __ Branch(&entry);

  // Load the current argument from the arguments array and push it to the
  // stack.
  // a0: current argument index
  __ bind(&loop);
  __ lw(a1, MemOperand(fp, kArgsOffset));
  __ push(a1);
  __ push(a0);

  // Call the runtime to access the property in the arguments array.
  __ CallRuntime(Runtime::kGetProperty, 2);
  __ push(v0);

  // Use inline caching to access the arguments.
  __ lw(a0, MemOperand(fp, kIndexOffset));
  __ Addu(a0, a0, Operand(1 << kSmiTagSize));
  __ sw(a0, MemOperand(fp, kIndexOffset));

  // Test if the copy loop has finished copying all the elements from the
  // arguments object.
  __ bind(&entry);
  __ lw(a1, MemOperand(fp, kLimitOffset));
  __ Branch(&loop, ne, a0, Operand(a1));
  // Invoke the function.
  ParameterCount actual(a0);
  __ sra(a0, a0, kSmiTagSize);
  __ lw(a1, MemOperand(fp, kFunctionOffset));
  __ InvokeFunction(a1, actual, CALL_FUNCTION,
                    NullCallWrapper(), CALL_AS_METHOD);

  // Tear down the internal frame and remove function, receiver and args.
  __ LeaveInternalFrame();
  __ Addu(sp, sp, Operand(3 * kPointerSize));
  __ Ret();
}


static void EnterArgumentsAdaptorFrame(MacroAssembler* masm) {
  __ sll(a0, a0, kSmiTagSize);
  __ li(t0, Operand(Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR)));
  __ MultiPush(a0.bit() | a1.bit() | t0.bit() | fp.bit() | ra.bit());
  __ Addu(fp, sp, Operand(3 * kPointerSize));
}


static void LeaveArgumentsAdaptorFrame(MacroAssembler* masm) {
  // ----------- S t a t e -------------
  //  -- v0 : result being passed through
  // -----------------------------------
  // Get the number of arguments passed (as a smi), tear down the frame and
  // then tear down the parameters.
  __ lw(a1, MemOperand(fp, -3 * kPointerSize));
  __ mov(sp, fp);
  __ MultiPop(fp.bit() | ra.bit());
  __ sll(t0, a1, kPointerSizeLog2 - kSmiTagSize);
  __ Addu(sp, sp, t0);
  // Adjust for the receiver.
  __ Addu(sp, sp, Operand(kPointerSize));
}


void Builtins::Generate_ArgumentsAdaptorTrampoline(MacroAssembler* masm) {
  // State setup as expected by MacroAssembler::InvokePrologue.
  // ----------- S t a t e -------------
  //  -- a0: actual arguments count
  //  -- a1: function (passed through to callee)
  //  -- a2: expected arguments count
  //  -- a3: callee code entry
  //  -- t1: call kind information
  // -----------------------------------

  Label invoke, dont_adapt_arguments;

  Label enough, too_few;
  __ Branch(&dont_adapt_arguments, eq,
      a2, Operand(SharedFunctionInfo::kDontAdaptArgumentsSentinel));
  // We use Uless as the number of argument should always be greater than 0.
  __ Branch(&too_few, Uless, a0, Operand(a2));

  {  // Enough parameters: actual >= expected.
    // a0: actual number of arguments as a smi
    // a1: function
    // a2: expected number of arguments
    // a3: code entry to call
    __ bind(&enough);
    EnterArgumentsAdaptorFrame(masm);

    // Calculate copy start address into a0 and copy end address into a2.
    __ sll(a0, a0, kPointerSizeLog2 - kSmiTagSize);
    __ Addu(a0, fp, a0);
    // Adjust for return address and receiver.
    __ Addu(a0, a0, Operand(2 * kPointerSize));
    // Compute copy end address.
    __ sll(a2, a2, kPointerSizeLog2);
    __ subu(a2, a0, a2);

    // Copy the arguments (including the receiver) to the new stack frame.
    // a0: copy start address
    // a1: function
    // a2: copy end address
    // a3: code entry to call

    Label copy;
    __ bind(&copy);
    __ lw(t0, MemOperand(a0));
    __ push(t0);
    __ Branch(USE_DELAY_SLOT, &copy, ne, a0, Operand(a2));
    __ addiu(a0, a0, -kPointerSize);  // In delay slot.

    __ jmp(&invoke);
  }

  {  // Too few parameters: Actual < expected.
    __ bind(&too_few);
    EnterArgumentsAdaptorFrame(masm);

    // TODO(MIPS): Optimize these loops.

    // Calculate copy start address into a0 and copy end address is fp.
    // a0: actual number of arguments as a smi
    // a1: function
    // a2: expected number of arguments
    // a3: code entry to call
    __ sll(a0, a0, kPointerSizeLog2 - kSmiTagSize);
    __ Addu(a0, fp, a0);
    // Adjust for return address and receiver.
    __ Addu(a0, a0, Operand(2 * kPointerSize));
    // Compute copy end address. Also adjust for return address.
    __ Addu(t3, fp, kPointerSize);

    // Copy the arguments (including the receiver) to the new stack frame.
    // a0: copy start address
    // a1: function
    // a2: expected number of arguments
    // a3: code entry to call
    // t3: copy end address
    Label copy;
    __ bind(&copy);
    __ lw(t0, MemOperand(a0));  // Adjusted above for return addr and receiver.
    __ push(t0);
    __ Subu(a0, a0, kPointerSize);
    __ Branch(&copy, ne, a0, Operand(t3));

    // Fill the remaining expected arguments with undefined.
    // a1: function
    // a2: expected number of arguments
    // a3: code entry to call
    __ LoadRoot(t0, Heap::kUndefinedValueRootIndex);
    __ sll(t2, a2, kPointerSizeLog2);
    __ Subu(a2, fp, Operand(t2));
    __ Addu(a2, a2, Operand(-4 * kPointerSize));  // Adjust for frame.

    Label fill;
    __ bind(&fill);
    __ push(t0);
    __ Branch(&fill, ne, sp, Operand(a2));
  }

  // Call the entry point.
  __ bind(&invoke);

  __ Call(a3);

  // Exit frame and return.
  LeaveArgumentsAdaptorFrame(masm);
  __ Ret();


  // -------------------------------------------
  // Don't adapt arguments.
  // -------------------------------------------
  __ bind(&dont_adapt_arguments);
  __ Jump(a3);
}


#undef __

} }  // namespace v8::internal

#endif  // V8_TARGET_ARCH_MIPS