Merge experimental/a64 to bleeding_edge.

src/a64/builtins-a64.cc

+// Copyright 2013 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
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "v8.h"
+
+#if V8_TARGET_ARCH_A64
+
+#include "codegen.h"
+#include "debug.h"
+#include "deoptimizer.h"
+#include "full-codegen.h"
+#include "runtime.h"
+#include "stub-cache.h"
+
+namespace v8 {
+namespace internal {
+
+
+#define __ ACCESS_MASM(masm)
+
+
+// Load the built-in Array function from the current context.
+static void GenerateLoadArrayFunction(MacroAssembler* masm, Register result) {
+  // Load the native context.
+  __ Ldr(result, GlobalObjectMemOperand());
+  __ Ldr(result,
+         FieldMemOperand(result, GlobalObject::kNativeContextOffset));
+  // Load the InternalArray function from the native context.
+  __ Ldr(result,
+         MemOperand(result,
+                    Context::SlotOffset(Context::ARRAY_FUNCTION_INDEX)));
+}
+
+
+// Load the built-in InternalArray function from the current context.
+static void GenerateLoadInternalArrayFunction(MacroAssembler* masm,
+                                              Register result) {
+  // Load the native context.
+  __ Ldr(result, GlobalObjectMemOperand());
+  __ Ldr(result,
+         FieldMemOperand(result, GlobalObject::kNativeContextOffset));
+  // Load the InternalArray function from the native context.
+  __ Ldr(result, ContextMemOperand(result,
+                                   Context::INTERNAL_ARRAY_FUNCTION_INDEX));
+}
+
+
+void Builtins::Generate_Adaptor(MacroAssembler* masm,
+                                CFunctionId id,
+                                BuiltinExtraArguments extra_args) {
+  // ----------- S t a t e -------------
+  //  -- x0                 : number of arguments excluding receiver
+  //  -- x1                 : called function (only guaranteed when
+  //                          extra_args requires it)
+  //  -- cp                 : context
+  //  -- sp[0]              : last argument
+  //  -- ...
+  //  -- sp[4 * (argc - 1)] : first argument (argc == x0)
+  //  -- sp[4 * argc]       : receiver
+  // -----------------------------------
+
+  // Insert extra arguments.
+  int num_extra_args = 0;
+  if (extra_args == NEEDS_CALLED_FUNCTION) {
+    num_extra_args = 1;
+    __ Push(x1);
+  } else {
+    ASSERT(extra_args == NO_EXTRA_ARGUMENTS);
+  }
+
+  // JumpToExternalReference expects x0 to contain the number of arguments
+  // including the receiver and the extra arguments.
+  __ Add(x0, x0, num_extra_args + 1);
+  __ JumpToExternalReference(ExternalReference(id, masm->isolate()));
+}
+
+
+void Builtins::Generate_InternalArrayCode(MacroAssembler* masm) {
+  // ----------- S t a t e -------------
+  //  -- x0     : number of arguments
+  //  -- lr     : return address
+  //  -- sp[...]: constructor arguments
+  // -----------------------------------
+  ASM_LOCATION("Builtins::Generate_InternalArrayCode");
+  Label generic_array_code;
+
+  // Get the InternalArray function.
+  GenerateLoadInternalArrayFunction(masm, x1);
+
+  if (FLAG_debug_code) {
+    // Initial map for the builtin InternalArray functions should be maps.
+    __ Ldr(x10, FieldMemOperand(x1, JSFunction::kPrototypeOrInitialMapOffset));
+    __ Tst(x10, kSmiTagMask);
+    __ Assert(ne, kUnexpectedInitialMapForInternalArrayFunction);
+    __ CompareObjectType(x10, x11, x12, MAP_TYPE);
+    __ Assert(eq, kUnexpectedInitialMapForInternalArrayFunction);
+  }
+
+  // Run the native code for the InternalArray function called as a normal
+  // function.
+  InternalArrayConstructorStub stub(masm->isolate());
+  __ TailCallStub(&stub);
+}
+
+
+void Builtins::Generate_ArrayCode(MacroAssembler* masm) {
+  // ----------- S t a t e -------------
+  //  -- x0     : number of arguments
+  //  -- lr     : return address
+  //  -- sp[...]: constructor arguments
+  // -----------------------------------
+  ASM_LOCATION("Builtins::Generate_ArrayCode");
+  Label generic_array_code, one_or_more_arguments, two_or_more_arguments;
+
+  // Get the Array function.
+  GenerateLoadArrayFunction(masm, x1);
+
+  if (FLAG_debug_code) {
+    // Initial map for the builtin Array functions should be maps.
+    __ Ldr(x10, FieldMemOperand(x1, JSFunction::kPrototypeOrInitialMapOffset));
+    __ Tst(x10, kSmiTagMask);
+    __ Assert(ne, kUnexpectedInitialMapForArrayFunction);
+    __ CompareObjectType(x10, x11, x12, MAP_TYPE);
+    __ Assert(eq, kUnexpectedInitialMapForArrayFunction);
+  }
+
+  // Run the native code for the Array function called as a normal function.
+  Handle<Object> undefined_sentinel(
+      masm->isolate()->heap()->undefined_value(),
+      masm->isolate());
+  __ Mov(x2, Operand(undefined_sentinel));
+  ArrayConstructorStub stub(masm->isolate());
+  __ TailCallStub(&stub);
+}
+
+
+void Builtins::Generate_StringConstructCode(MacroAssembler* masm) {
+  // ----------- S t a t e -------------
+  //  -- x0                     : number of arguments
+  //  -- x1                     : constructor function
+  //  -- lr                     : return address
+  //  -- sp[(argc - n - 1) * 8] : arg[n] (zero based)
+  //  -- sp[argc * 8]           : receiver
+  // -----------------------------------
+  ASM_LOCATION("Builtins::Generate_StringConstructCode");
+  Counters* counters = masm->isolate()->counters();
+  __ IncrementCounter(counters->string_ctor_calls(), 1, x10, x11);
+
+  Register argc = x0;
+  Register function = x1;
+  if (FLAG_debug_code) {
+    __ LoadGlobalFunction(Context::STRING_FUNCTION_INDEX, x10);
+    __ Cmp(function, x10);
+    __ Assert(eq, kUnexpectedStringFunction);
+  }
+
+  // Load the first arguments in x0 and get rid of the rest.
+  Label no_arguments;
+  __ Cbz(argc, &no_arguments);
+  // First args = sp[(argc - 1) * 8].
+  __ Sub(argc, argc, 1);
+  __ Claim(argc, kXRegSizeInBytes);
+  // jssp now point to args[0], load and drop args[0] + receiver.
+  // TODO(jbramley): Consider adding ClaimAndPoke.
+  __ Ldr(argc, MemOperand(jssp, 2 * kPointerSize, PostIndex));
+
+  Register argument = x2;
+  Label not_cached, argument_is_string;
+  __ LookupNumberStringCache(argc,       // Input.
+                             argument,   // Result.
+                             x10,        // Scratch.
+                             x11,        // Scratch.
+                             x12,        // Scratch.
+                             &not_cached);
+  __ IncrementCounter(counters->string_ctor_cached_number(), 1, x10, x11);
+  __ Bind(&argument_is_string);
+
+  // ----------- S t a t e -------------
+  //  -- x2     : argument converted to string
+  //  -- x1     : constructor function
+  //  -- lr     : return address
+  // -----------------------------------
+
+  Label gc_required;
+  Register new_obj = x0;
+  __ Allocate(JSValue::kSize, new_obj, x10, x11, &gc_required, TAG_OBJECT);
+
+  // Initialize the String object.
+  Register map = x3;
+  __ LoadGlobalFunctionInitialMap(function, map, x10);
+  if (FLAG_debug_code) {
+    __ Ldrb(x4, FieldMemOperand(map, Map::kInstanceSizeOffset));
+    __ Cmp(x4, JSValue::kSize >> kPointerSizeLog2);
+    __ Assert(eq, kUnexpectedStringWrapperInstanceSize);
+    __ Ldrb(x4, FieldMemOperand(map, Map::kUnusedPropertyFieldsOffset));
+    __ Cmp(x4, 0);
+    __ Assert(eq, kUnexpectedUnusedPropertiesOfStringWrapper);
+  }
+  __ Str(map, FieldMemOperand(new_obj, HeapObject::kMapOffset));
+
+  Register empty = x3;
+  __ LoadRoot(empty, Heap::kEmptyFixedArrayRootIndex);
+  __ Str(empty, FieldMemOperand(new_obj, JSObject::kPropertiesOffset));
+  __ Str(empty, FieldMemOperand(new_obj, JSObject::kElementsOffset));
+
+  __ Str(argument, FieldMemOperand(new_obj, 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(argc, &convert_argument);
+
+  // Is it a String?
+  __ Ldr(x10, FieldMemOperand(x0, HeapObject::kMapOffset));
+  __ Ldrb(x11, FieldMemOperand(x10, Map::kInstanceTypeOffset));
+  __ Tbnz(x11, MaskToBit(kIsNotStringMask), &convert_argument);
+  __ Mov(argument, argc);
+  __ IncrementCounter(counters->string_ctor_string_value(), 1, x10, x11);
+  __ B(&argument_is_string);
+
+  // Invoke the conversion builtin and put the result into x2.
+  __ Bind(&convert_argument);
+  __ Push(function);  // Preserve the function.
+  __ IncrementCounter(counters->string_ctor_conversions(), 1, x10, x11);
+  {
+    FrameScope scope(masm, StackFrame::INTERNAL);
+    __ Push(argc);
+    __ InvokeBuiltin(Builtins::TO_STRING, CALL_FUNCTION);
+  }
+  __ Pop(function);
+  __ Mov(argument, x0);
+  __ B(&argument_is_string);
+
+  // Load the empty string into x2, remove the receiver from the
+  // stack, and jump back to the case where the argument is a string.
+  __ Bind(&no_arguments);
+  __ LoadRoot(argument, Heap::kempty_stringRootIndex);
+  __ Drop(1);
+  __ B(&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, x10, x11);
+  {
+    FrameScope scope(masm, StackFrame::INTERNAL);
+    __ Push(argument);
+    __ CallRuntime(Runtime::kNewStringWrapper, 1);
+  }
+  __ Ret();
+}
+
+
+static void CallRuntimePassFunction(MacroAssembler* masm,
+                                    Runtime::FunctionId function_id) {
+  FrameScope scope(masm, StackFrame::INTERNAL);
+  //   - Push a copy of the function onto the stack.
+  //   - Push another copy as a parameter to the runtime call.
+  __ Push(x1, x1);
+
+  __ CallRuntime(function_id, 1);
+
+  //   - Restore receiver.
+  __ Pop(x1);
+}
+
+
+static void GenerateTailCallToSharedCode(MacroAssembler* masm) {
+  __ Ldr(x2, FieldMemOperand(x1, JSFunction::kSharedFunctionInfoOffset));
+  __ Ldr(x2, FieldMemOperand(x2, SharedFunctionInfo::kCodeOffset));
+  __ Add(x2, x2, Code::kHeaderSize - kHeapObjectTag);
+  __ Br(x2);
+}
+
+
+static void GenerateTailCallToReturnedCode(MacroAssembler* masm) {
+  __ Add(x0, x0, Code::kHeaderSize - kHeapObjectTag);
+  __ Br(x0);
+}
+
+
+void Builtins::Generate_InOptimizationQueue(MacroAssembler* masm) {
+  // Checking whether the queued function is ready for install is optional,
+  // since we come across interrupts and stack checks elsewhere. However, not
+  // checking may delay installing ready functions, and always checking would be
+  // quite expensive. A good compromise is to first check against stack limit as
+  // a cue for an interrupt signal.
+  Label ok;
+  __ CompareRoot(masm->StackPointer(), Heap::kStackLimitRootIndex);
+  __ B(hs, &ok);
+
+  CallRuntimePassFunction(masm, Runtime::kTryInstallOptimizedCode);
+  GenerateTailCallToReturnedCode(masm);
+
+  __ Bind(&ok);
+  GenerateTailCallToSharedCode(masm);
+}
+
+
+static void Generate_JSConstructStubHelper(MacroAssembler* masm,
+                                           bool is_api_function,
+                                           bool count_constructions) {
+  // ----------- S t a t e -------------
+  //  -- x0     : number of arguments
+  //  -- x1     : constructor function
+  //  -- lr     : return address
+  //  -- sp[...]: constructor arguments
+  // -----------------------------------
+
+  ASM_LOCATION("Builtins::Generate_JSConstructStubHelper");
+  // Should never count constructions for api objects.
+  ASSERT(!is_api_function || !count_constructions);
+
+  Isolate* isolate = masm->isolate();
+
+  // Enter a construct frame.
+  {
+    FrameScope scope(masm, StackFrame::CONSTRUCT);
+
+    // Preserve the two incoming parameters on the stack.
+    Register argc = x0;
+    Register constructor = x1;
+    // x1: constructor function
+    __ SmiTag(argc);
+    __ Push(argc, constructor);
+    // sp[0] : Constructor function.
+    // sp[1]: number of arguments (smi-tagged)
+
+    // 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.
+    Label rt_call, allocated;
+    if (FLAG_inline_new) {
+      Label undo_allocation;
+#if ENABLE_DEBUGGER_SUPPORT
+      ExternalReference debug_step_in_fp =
+          ExternalReference::debug_step_in_fp_address(isolate);
+      __ Mov(x2, Operand(debug_step_in_fp));
+      __ Ldr(x2, MemOperand(x2));
+      __ Cbnz(x2, &rt_call);
+#endif
+      // Load the initial map and verify that it is in fact a map.
+      Register init_map = x2;
+      __ Ldr(init_map,
+             FieldMemOperand(constructor,
+                             JSFunction::kPrototypeOrInitialMapOffset));
+      __ JumpIfSmi(init_map, &rt_call);
+      __ JumpIfNotObjectType(init_map, x10, x11, MAP_TYPE, &rt_call);
+
+      // 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.
+      __ CompareInstanceType(init_map, x10, JS_FUNCTION_TYPE);
+      __ B(eq, &rt_call);
+
+      if (count_constructions) {
+        Label allocate;
+        // Decrease generous allocation count.
+        __ Ldr(x3, FieldMemOperand(constructor,
+                                   JSFunction::kSharedFunctionInfoOffset));
+        MemOperand constructor_count =
+            FieldMemOperand(x3, SharedFunctionInfo::kConstructionCountOffset);
+        __ Ldrb(x4, constructor_count);
+        __ Subs(x4, x4, 1);
+        __ Strb(x4, constructor_count);
+        __ B(ne, &allocate);
+
+        // Push the constructor and map to the stack, and the constructor again
+        // as argument to the runtime call.
+        __ Push(constructor, init_map, constructor);
+        // The call will replace the stub, so the countdown is only done once.
+        __ CallRuntime(Runtime::kFinalizeInstanceSize, 1);
+        __ Pop(init_map, constructor);
+        __ Bind(&allocate);
+      }
+
+      // Now allocate the JSObject on the heap.
+      Register obj_size = x3;
+      Register new_obj = x4;
+      __ Ldrb(obj_size, FieldMemOperand(init_map, Map::kInstanceSizeOffset));
+      __ Allocate(obj_size, new_obj, x10, x11, &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.
+      // NB. the object pointer is not tagged, so MemOperand is used.
+      Register empty = x5;
+      __ LoadRoot(empty, Heap::kEmptyFixedArrayRootIndex);
+      __ Str(init_map, MemOperand(new_obj, JSObject::kMapOffset));
+      __ Str(empty, MemOperand(new_obj, JSObject::kPropertiesOffset));
+      __ Str(empty, MemOperand(new_obj, JSObject::kElementsOffset));
+
+      Register first_prop = x5;
+      __ Add(first_prop, new_obj, JSObject::kHeaderSize);
+
+      // Fill all of the in-object properties with the appropriate filler.
+      Register obj_end = x6;
+      __ Add(obj_end, new_obj, Operand(obj_size, LSL, kPointerSizeLog2));
+      Register undef = x7;
+      __ LoadRoot(undef, Heap::kUndefinedValueRootIndex);
+
+      // Obtain number of pre-allocated property fields and in-object
+      // properties.
+      Register prealloc_fields = x10;
+      Register inobject_props = x11;
+      Register inst_sizes = x11;
+      __ Ldr(inst_sizes, FieldMemOperand(init_map, Map::kInstanceSizesOffset));
+      __ Ubfx(prealloc_fields, inst_sizes,
+              Map::kPreAllocatedPropertyFieldsByte * kBitsPerByte,
+              kBitsPerByte);
+      __ Ubfx(inobject_props, inst_sizes,
+              Map::kInObjectPropertiesByte * kBitsPerByte, kBitsPerByte);
+
+      if (count_constructions) {
+        // Register first_non_prealloc is the offset of the first field after
+        // pre-allocated fields.
+        Register first_non_prealloc = x12;
+        __ Add(first_non_prealloc, first_prop,
+               Operand(prealloc_fields, LSL, kPointerSizeLog2));
+
+        if (FLAG_debug_code) {
+          __ Cmp(first_non_prealloc, obj_end);
+          __ Assert(le, kUnexpectedNumberOfPreAllocatedPropertyFields);
+        }
+        __ InitializeFieldsWithFiller(first_prop, first_non_prealloc, undef);
+        // To allow for truncation.
+        __ LoadRoot(x12, Heap::kOnePointerFillerMapRootIndex);
+        __ InitializeFieldsWithFiller(first_prop, obj_end, x12);
+      } else {
+        __ InitializeFieldsWithFiller(first_prop, obj_end, undef);
+      }
+
+      // 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.
+      __ Add(new_obj, new_obj, kHeapObjectTag);
+
+      // Check if a non-empty properties array is needed. Continue with
+      // allocated object if not, or fall through to runtime call if it is.
+      Register element_count = x3;
+      __ Ldrb(x3, FieldMemOperand(init_map, Map::kUnusedPropertyFieldsOffset));
+      // The field instance sizes contains both pre-allocated property fields
+      // and in-object properties.
+      __ Add(x3, x3, prealloc_fields);
+      __ Subs(element_count, x3, inobject_props);
+
+      // Done if no extra properties are to be allocated.
+      __ B(eq, &allocated);
+      __ Assert(pl, kPropertyAllocationCountFailed);
+
+      // Scale the number of elements by pointer size and add the header for
+      // FixedArrays to the start of the next object calculation from above.
+      Register new_array = x5;
+      Register array_size = x6;
+      __ Add(array_size, element_count, FixedArray::kHeaderSize / kPointerSize);
+      __ Allocate(array_size, new_array, x11, x12, &undo_allocation,
+                  static_cast<AllocationFlags>(RESULT_CONTAINS_TOP |
+                                               SIZE_IN_WORDS));
+
+      Register array_map = x10;
+      __ LoadRoot(array_map, Heap::kFixedArrayMapRootIndex);
+      __ Str(array_map, MemOperand(new_array, FixedArray::kMapOffset));
+      __ SmiTag(x0, element_count);
+      __ Str(x0, MemOperand(new_array, FixedArray::kLengthOffset));
+
+      // Initialize the fields to undefined.
+      Register elements = x10;
+      Register elements_end  = x11;
+      __ Add(elements, new_array, FixedArray::kHeaderSize);
+      __ Add(elements_end, elements,
+             Operand(element_count, LSL, kPointerSizeLog2));
+      __ InitializeFieldsWithFiller(elements, elements_end, undef);
+
+      // Store the initialized FixedArray into the properties field of the
+      // JSObject.
+      __ Add(new_array, new_array, kHeapObjectTag);
+      __ Str(new_array, FieldMemOperand(new_obj, JSObject::kPropertiesOffset));
+
+      // Continue with JSObject being successfully allocated.
+      __ B(&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.
+      __ Bind(&undo_allocation);
+      __ UndoAllocationInNewSpace(new_obj, x14);
+    }
+
+    // Allocate the new receiver object using the runtime call.
+    __ Bind(&rt_call);
+    __ Push(constructor);  // Argument for Runtime_NewObject.
+    __ CallRuntime(Runtime::kNewObject, 1);
+    __ Mov(x4, x0);
+
+    // Receiver for constructor call allocated.
+    // x4: JSObject
+    __ Bind(&allocated);
+    __ Push(x4, x4);
+
+    // Reload the number of arguments from the stack.
+    // Set it up in x0 for the function call below.
+    // jssp[0]: receiver
+    // jssp[1]: receiver
+    // jssp[2]: constructor function
+    // jssp[3]: number of arguments (smi-tagged)
+    __ Peek(constructor, 2 * kXRegSizeInBytes);  // Load constructor.
+    __ Peek(argc, 3 * kXRegSizeInBytes);  // Load number of arguments.
+    __ SmiUntag(argc);
+
+    // Set up pointer to last argument.
+    __ Add(x2, fp, StandardFrameConstants::kCallerSPOffset);
+
+    // Copy arguments and receiver to the expression stack.
+    // Copy 2 values every loop to use ldp/stp.
+    // x0: number of arguments
+    // x1: constructor function
+    // x2: address of last argument (caller sp)
+    // jssp[0]: receiver
+    // jssp[1]: receiver
+    // jssp[2]: constructor function
+    // jssp[3]: number of arguments (smi-tagged)
+    // Compute the start address of the copy in x3.
+    __ Add(x3, x2, Operand(argc, LSL, kPointerSizeLog2));
+    Label loop, entry, done_copying_arguments;
+    __ B(&entry);
+    __ Bind(&loop);
+    __ Ldp(x10, x11, MemOperand(x3, -2 * kPointerSize, PreIndex));
+    __ Push(x11, x10);
+    __ Bind(&entry);
+    __ Cmp(x3, x2);
+    __ B(gt, &loop);
+    // Because we copied values 2 by 2 we may have copied one extra value.
+    // Drop it if that is the case.
+    __ B(eq, &done_copying_arguments);
+    __ Drop(1);
+    __ Bind(&done_copying_arguments);
+
+    // Call the function.
+    // x0: number of arguments
+    // x1: constructor function
+    if (is_api_function) {
+      __ Ldr(cp, FieldMemOperand(constructor, JSFunction::kContextOffset));
+      Handle<Code> code =
+          masm->isolate()->builtins()->HandleApiCallConstruct();
+      __ Call(code, RelocInfo::CODE_TARGET);
+    } else {
+      ParameterCount actual(argc);
+      __ InvokeFunction(constructor, actual, CALL_FUNCTION, NullCallWrapper());
+    }
+
+    // Store offset of return address for deoptimizer.
+    if (!is_api_function && !count_constructions) {
+      masm->isolate()->heap()->SetConstructStubDeoptPCOffset(masm->pc_offset());
+    }
+
+    // Restore the context from the frame.
+    // x0: result
+    // jssp[0]: receiver
+    // jssp[1]: constructor function
+    // jssp[2]: number of arguments (smi-tagged)
+    __ Ldr(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.
+    // x0: result
+    // jssp[0]: receiver (newly allocated object)
+    // jssp[1]: constructor function
+    // jssp[2]: number of arguments (smi-tagged)
+    __ JumpIfSmi(x0, &use_receiver);
+
+    // 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.
+    __ JumpIfObjectType(x0, x1, x3, FIRST_SPEC_OBJECT_TYPE, &exit, ge);
+
+    // Throw away the result of the constructor invocation and use the
+    // on-stack receiver as the result.
+    __ Bind(&use_receiver);
+    __ Peek(x0, 0);
+
+    // Remove the receiver from the stack, remove caller arguments, and
+    // return.
+    __ Bind(&exit);
+    // x0: result
+    // jssp[0]: receiver (newly allocated object)
+    // jssp[1]: constructor function
+    // jssp[2]: number of arguments (smi-tagged)
+    __ Peek(x1, 2 * kXRegSizeInBytes);
+
+    // Leave construct frame.
+  }
+
+  __ DropBySMI(x1);
+  __ Drop(1);
+  __ IncrementCounter(isolate->counters()->constructed_objects(), 1, x1, x2);
+  __ 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);
+}
+
+
+// Input:
+//   x0: code entry.
+//   x1: function.
+//   x2: receiver.
+//   x3: argc.
+//   x4: argv.
+// Output:
+//   x0: result.
+static void Generate_JSEntryTrampolineHelper(MacroAssembler* masm,
+                                             bool is_construct) {
+  // Called from JSEntryStub::GenerateBody().
+  Register function = x1;
+  Register receiver = x2;
+  Register argc = x3;
+  Register argv = x4;
+
+  ProfileEntryHookStub::MaybeCallEntryHook(masm);
+
+  // Clear the context before we push it when entering the internal frame.
+  __ Mov(cp, 0);
+
+  {
+    // Enter an internal frame.
+    FrameScope scope(masm, StackFrame::INTERNAL);
+
+    // Set up the context from the function argument.
+    __ Ldr(cp, FieldMemOperand(function, JSFunction::kContextOffset));
+
+    __ InitializeRootRegister();
+
+    // Push the function and the receiver onto the stack.
+    __ Push(function, receiver);
+
+    // Copy arguments to the stack in a loop, in reverse order.
+    // x3: argc.
+    // x4: argv.
+    Label loop, entry;
+    // Compute the copy end address.
+    __ Add(x10, argv, Operand(argc, LSL, kPointerSizeLog2));
+
+    // TODO(all): This can potentially be optimized with ldp/stp to speed up
+    // arguments passing from C++ to JS.
+    __ B(&entry);
+    __ Bind(&loop);
+    __ Ldr(x11, MemOperand(argv, kPointerSize, PostIndex));
+    __ Ldr(x12, MemOperand(x11));  // Dereference the handle.
+    __ Push(x12);  // Push the argument.
+    __ Bind(&entry);
+    __ Cmp(x10, argv);
+    __ B(ne, &loop);
+
+    // Initialize all JavaScript callee-saved registers, since they will be seen
+    // by the garbage collector as part of handlers.
+    // The original values have been saved in JSEntryStub::GenerateBody().
+    __ LoadRoot(x19, Heap::kUndefinedValueRootIndex);
+    __ Mov(x20, x19);
+    __ Mov(x21, x19);
+    __ Mov(x22, x19);
+    __ Mov(x23, x19);
+    __ Mov(x24, x19);
+    __ Mov(x25, x19);
+    // Don't initialize the reserved registers.
+    // x26 : root register (root).
+    // x27 : context pointer (cp).
+    // x28 : JS stack pointer (jssp).
+    // x29 : frame pointer (fp).
+
+    // TODO(alexandre): Revisit the MAsm function invocation mechanisms.
+    // Currently there is a mix of statically and dynamically allocated
+    // registers.
+    __ Mov(x0, argc);
+    if (is_construct) {
+      // No type feedback cell is available.
+      Handle<Object> undefined_sentinel(
+          masm->isolate()->heap()->undefined_value(), masm->isolate());
+      __ Mov(x2, Operand(undefined_sentinel));
+
+      CallConstructStub stub(NO_CALL_FUNCTION_FLAGS);
+      __ CallStub(&stub);
+    } else {
+      ParameterCount actual(x0);
+      __ InvokeFunction(function, actual, CALL_FUNCTION, NullCallWrapper());
+    }
+    // Exit the JS internal frame and remove the parameters (except function),
+    // and return.
+  }
+
+  // Result is in x0. Return.
+  __ Ret();
+}
+
+
+void Builtins::Generate_JSEntryTrampoline(MacroAssembler* masm) {
+  Generate_JSEntryTrampolineHelper(masm, false);
+}
+
+
+void Builtins::Generate_JSConstructEntryTrampoline(MacroAssembler* masm) {
+  Generate_JSEntryTrampolineHelper(masm, true);
+}
+
+
+void Builtins::Generate_CompileUnoptimized(MacroAssembler* masm) {
+  CallRuntimePassFunction(masm, Runtime::kCompileUnoptimized);
+  GenerateTailCallToReturnedCode(masm);
+}
+
+
+static void CallCompileOptimized(MacroAssembler* masm, bool concurrent) {
+  FrameScope scope(masm, StackFrame::INTERNAL);
+  Register function = x1;
+
+  // Preserve function. At the same time, push arguments for
+  // kCompileOptimized.
+  __ LoadObject(x10, masm->isolate()->factory()->ToBoolean(concurrent));
+  __ Push(function, function, x10);
+
+  __ CallRuntime(Runtime::kCompileOptimized, 2);
+
+  // Restore receiver.
+  __ Pop(function);
+}
+
+
+void Builtins::Generate_CompileOptimized(MacroAssembler* masm) {
+  CallCompileOptimized(masm, false);
+  GenerateTailCallToReturnedCode(masm);
+}
+
+
+void Builtins::Generate_CompileOptimizedConcurrent(MacroAssembler* masm) {
+  CallCompileOptimized(masm, true);
+  GenerateTailCallToReturnedCode(masm);
+}
+
+
+static void GenerateMakeCodeYoungAgainCommon(MacroAssembler* masm) {
+  // For now, we are relying on the fact that make_code_young doesn't do any
+  // garbage collection which allows us to save/restore the registers without
+  // worrying about which of them contain pointers. We also don't build an
+  // internal frame to make the code fast, since we shouldn't have to do stack
+  // crawls in MakeCodeYoung. This seems a bit fragile.
+
+  // The following caller-saved registers must be saved and restored when
+  // calling through to the runtime:
+  //   x0 - The address from which to resume execution.
+  //   x1 - isolate
+  //   lr - The return address for the JSFunction itself. It has not yet been
+  //        preserved on the stack because the frame setup code was replaced
+  //        with a call to this stub, to handle code ageing.
+  {
+    FrameScope scope(masm, StackFrame::MANUAL);
+    __ Push(x0, x1, fp, lr);
+    __ Mov(x1, Operand(ExternalReference::isolate_address(masm->isolate())));
+    __ CallCFunction(
+        ExternalReference::get_make_code_young_function(masm->isolate()), 2);
+    __ Pop(lr, fp, x1, x0);
+  }
+
+  // The calling function has been made young again, so return to execute the
+  // real frame set-up code.
+  __ Br(x0);
+}
+
+#define DEFINE_CODE_AGE_BUILTIN_GENERATOR(C)                 \
+void Builtins::Generate_Make##C##CodeYoungAgainEvenMarking(  \
+    MacroAssembler* masm) {                                  \
+  GenerateMakeCodeYoungAgainCommon(masm);                    \
+}                                                            \
+void Builtins::Generate_Make##C##CodeYoungAgainOddMarking(   \
+    MacroAssembler* masm) {                                  \
+  GenerateMakeCodeYoungAgainCommon(masm);                    \
+}
+CODE_AGE_LIST(DEFINE_CODE_AGE_BUILTIN_GENERATOR)
+#undef DEFINE_CODE_AGE_BUILTIN_GENERATOR
+
+
+void Builtins::Generate_MarkCodeAsExecutedOnce(MacroAssembler* masm) {
+  // For now, as in GenerateMakeCodeYoungAgainCommon, we are relying on the fact
+  // that make_code_young doesn't do any garbage collection which allows us to
+  // save/restore the registers without worrying about which of them contain
+  // pointers.
+
+  // The following caller-saved registers must be saved and restored when
+  // calling through to the runtime:
+  //   x0 - The address from which to resume execution.
+  //   x1 - isolate
+  //   lr - The return address for the JSFunction itself. It has not yet been
+  //        preserved on the stack because the frame setup code was replaced
+  //        with a call to this stub, to handle code ageing.
+  {
+    FrameScope scope(masm, StackFrame::MANUAL);
+    __ Push(x0, x1, fp, lr);
+    __ Mov(x1, Operand(ExternalReference::isolate_address(masm->isolate())));
+    __ CallCFunction(
+        ExternalReference::get_mark_code_as_executed_function(
+            masm->isolate()), 2);
+    __ Pop(lr, fp, x1, x0);
+
+    // Perform prologue operations usually performed by the young code stub.
+    __ EmitFrameSetupForCodeAgePatching(masm);
+  }
+
+  // Jump to point after the code-age stub.
+  __ Add(x0, x0, kCodeAgeSequenceSize);
+  __ Br(x0);
+}
+
+
+void Builtins::Generate_MarkCodeAsExecutedTwice(MacroAssembler* masm) {
+  GenerateMakeCodeYoungAgainCommon(masm);
+}
+
+
+static void Generate_NotifyStubFailureHelper(MacroAssembler* masm,
+                                             SaveFPRegsMode save_doubles) {
+  {
+    FrameScope scope(masm, StackFrame::INTERNAL);
+
+    // Preserve registers across notification, this is important for compiled
+    // stubs that tail call the runtime on deopts passing their parameters in
+    // registers.
+    // TODO(jbramley): Is it correct (and appropriate) to use safepoint
+    // registers here? According to the comment above, we should only need to
+    // preserve the registers with parameters.
+    __ PushXRegList(kSafepointSavedRegisters);
+    // Pass the function and deoptimization type to the runtime system.
+    __ CallRuntime(Runtime::kNotifyStubFailure, 0, save_doubles);
+    __ PopXRegList(kSafepointSavedRegisters);
+  }
+
+  // Ignore state (pushed by Deoptimizer::EntryGenerator::Generate).
+  __ Drop(1);
+
+  // Jump to the miss handler. Deoptimizer::EntryGenerator::Generate loads this
+  // into lr before it jumps here.
+  __ Br(lr);
+}
+
+
+void Builtins::Generate_NotifyStubFailure(MacroAssembler* masm) {
+  Generate_NotifyStubFailureHelper(masm, kDontSaveFPRegs);
+}
+
+
+void Builtins::Generate_NotifyStubFailureSaveDoubles(MacroAssembler* masm) {
+  Generate_NotifyStubFailureHelper(masm, kSaveFPRegs);
+}
+
+
+static void Generate_NotifyDeoptimizedHelper(MacroAssembler* masm,
+                                             Deoptimizer::BailoutType type) {
+  {
+    FrameScope scope(masm, StackFrame::INTERNAL);
+    // Pass the deoptimization type to the runtime system.
+    __ Mov(x0, Operand(Smi::FromInt(static_cast<int>(type))));
+    __ Push(x0);
+    __ CallRuntime(Runtime::kNotifyDeoptimized, 1);
+  }
+
+  // Get the full codegen state from the stack and untag it.
+  Register state = x6;
+  __ Peek(state, 0);
+  __ SmiUntag(state);
+
+  // Switch on the state.
+  Label with_tos_register, unknown_state;
+  __ CompareAndBranch(
+      state, FullCodeGenerator::NO_REGISTERS, ne, &with_tos_register);
+  __ Drop(1);  // Remove state.
+  __ Ret();
+
+  __ Bind(&with_tos_register);
+  // Reload TOS register.
+  __ Peek(x0, kPointerSize);
+  __ CompareAndBranch(state, FullCodeGenerator::TOS_REG, ne, &unknown_state);
+  __ Drop(2);  // Remove state and TOS.
+  __ Ret();
+
+  __ Bind(&unknown_state);
+  __ Abort(kInvalidFullCodegenState);
+}
+
+
+void Builtins::Generate_NotifyDeoptimized(MacroAssembler* masm) {
+  Generate_NotifyDeoptimizedHelper(masm, Deoptimizer::EAGER);
+}
+
+
+void Builtins::Generate_NotifyLazyDeoptimized(MacroAssembler* masm) {
+  Generate_NotifyDeoptimizedHelper(masm, Deoptimizer::LAZY);
+}
+
+
+void Builtins::Generate_NotifySoftDeoptimized(MacroAssembler* masm) {
+  Generate_NotifyDeoptimizedHelper(masm, Deoptimizer::SOFT);
+}
+
+
+void Builtins::Generate_OnStackReplacement(MacroAssembler* masm) {
+  // Lookup the function in the JavaScript frame.
+  __ Ldr(x0, MemOperand(fp, JavaScriptFrameConstants::kFunctionOffset));
+  {
+    FrameScope scope(masm, StackFrame::INTERNAL);
+    // Pass function as argument.
+    __ Push(x0);
+    __ CallRuntime(Runtime::kCompileForOnStackReplacement, 1);
+  }
+
+  // If the code object is null, just return to the unoptimized code.
+  Label skip;
+  __ CompareAndBranch(x0, Operand(Smi::FromInt(0)), ne, &skip);
+  __ Ret();
+
+  __ Bind(&skip);
+
+  // Load deoptimization data from the code object.
+  // <deopt_data> = <code>[#deoptimization_data_offset]
+  __ Ldr(x1, MemOperand(x0, Code::kDeoptimizationDataOffset - kHeapObjectTag));
+
+  // Load the OSR entrypoint offset from the deoptimization data.
+  // <osr_offset> = <deopt_data>[#header_size + #osr_pc_offset]
+  __ Ldrsw(w1, UntagSmiFieldMemOperand(x1, FixedArray::OffsetOfElementAt(
+      DeoptimizationInputData::kOsrPcOffsetIndex)));
+
+  // Compute the target address = code_obj + header_size + osr_offset
+  // <entry_addr> = <code_obj> + #header_size + <osr_offset>
+  __ Add(x0, x0, x1);
+  __ Add(lr, x0, Code::kHeaderSize - kHeapObjectTag);
+
+  // And "return" to the OSR entry point of the function.
+  __ Ret();
+}
+
+
+void Builtins::Generate_OsrAfterStackCheck(MacroAssembler* masm) {
+  // We check the stack limit as indicator that recompilation might be done.
+  Label ok;
+  __ CompareRoot(jssp, Heap::kStackLimitRootIndex);
+  __ B(hs, &ok);
+  {
+    FrameScope scope(masm, StackFrame::INTERNAL);
+    __ CallRuntime(Runtime::kStackGuard, 0);
+  }
+  __ Jump(masm->isolate()->builtins()->OnStackReplacement(),
+          RelocInfo::CODE_TARGET);
+
+  __ Bind(&ok);
+  __ Ret();
+}
+
+
+void Builtins::Generate_FunctionCall(MacroAssembler* masm) {
+  Register receiver_type = x13;
+
+  ASM_LOCATION("Builtins::Generate_FunctionCall");
+  // TODO(all/rames): Optimize and use named registers.
+  // 1. Make sure we have at least one argument.
+  // x0: actual number of arguments
+  { Label done;
+    __ Cbnz(x0, &done);
+    __ LoadRoot(x10, Heap::kUndefinedValueRootIndex);
+    __ Push(x10);
+    __ Mov(x0, 1);
+    __ Bind(&done);
+  }
+
+  // 2. Get the function to call (passed as receiver) from the stack, check
+  //    if it is a function.
+  // x0: actual number of arguments
+  Label slow, non_function;
+  // TODO(jbramley): Consider giving Peek a unit_size parameter, like Claim and
+  // Drop. This usage pattern is very common.
+  __ Peek(x1, Operand(x0, LSL, kXRegSizeInBytesLog2));
+  __ JumpIfSmi(x1, &non_function);
+  __ JumpIfNotObjectType(x1, x10, receiver_type, JS_FUNCTION_TYPE, &slow);
+
+  // 3a. Patch the first argument if necessary when calling a function.
+  // x0: actual number of arguments
+  // x1: function
+  Label shift_arguments;
+  __ Mov(x4, 0);  // Indicates a regular JS_FUNCTION.
+  { Label convert_to_object, use_global_receiver, patch_receiver;
+    // Change context eagerly in case we need the global receiver.
+    __ Ldr(cp, FieldMemOperand(x1, JSFunction::kContextOffset));
+
+    // Do not transform the receiver for strict mode functions.
+    __ Ldr(x10, FieldMemOperand(x1, JSFunction::kSharedFunctionInfoOffset));
+    __ Ldr(w11, FieldMemOperand(x10, SharedFunctionInfo::kCompilerHintsOffset));
+    __ Tbnz(x11, SharedFunctionInfo::kStrictModeFunction, &shift_arguments);
+
+    // TODO(all): Shoudld we insert space to avoid BTAC collisions?
+    // Do not transform the receiver for native (Compilerhints already in x3).
+    __ Tbnz(x11, SharedFunctionInfo::kNative, &shift_arguments);
+
+    // Compute the receiver in non-strict mode.
+    __ Sub(x10, x0, 1);
+    __ Peek(x2, Operand(x10, LSL, kXRegSizeInBytesLog2));
+    // x0: actual number of arguments
+    // x1: function
+    // x2: first argument
+    __ JumpIfSmi(x2, &convert_to_object);
+
+    // TODO(all): We could potentially work to optimize loads of root values.
+    // TODO(all): If the indexes are successive we can use 'ldp'.
+    __ JumpIfRoot(x2, Heap::kUndefinedValueRootIndex, &use_global_receiver);
+    __ JumpIfRoot(x2, Heap::kNullValueRootIndex, &use_global_receiver);
+
+    STATIC_ASSERT(LAST_SPEC_OBJECT_TYPE == LAST_TYPE);
+    __ JumpIfObjectType(x2, x10, x11, FIRST_SPEC_OBJECT_TYPE, &shift_arguments,
+                        ge);
+
+    __ Bind(&convert_to_object);
+
+    {
+      // Enter an internal frame in order to preserve argument count.
+      FrameScope scope(masm, StackFrame::INTERNAL);
+      __ SmiTag(x0);
+
+      __ Push(x0, x2);
+      __ InvokeBuiltin(Builtins::TO_OBJECT, CALL_FUNCTION);
+      __ Mov(x2, x0);
+
+      __ Pop(x0);
+      __ SmiUntag(x0);
+
+      // Exit the internal frame.
+    }
+
+    // Restore the function to x1, and the flag to x4.
+    __ Peek(x1, Operand(x0, LSL, kXRegSizeInBytesLog2));
+    __ Mov(x4, 0);
+    __ B(&patch_receiver);
+
+    __ Bind(&use_global_receiver);
+    __ Ldr(x2, GlobalObjectMemOperand());
+    __ Ldr(x2, FieldMemOperand(x2, GlobalObject::kGlobalReceiverOffset));
+
+    __ Bind(&patch_receiver);
+    __ Sub(x10, x0, 1);
+    __ Poke(x2, Operand(x10, LSL, kXRegSizeInBytesLog2));
+
+    __ B(&shift_arguments);
+  }
+
+  // 3b. Check for function proxy.
+  __ Bind(&slow);
+  __ Mov(x4, 1);  // Indicate function proxy.
+  __ Cmp(receiver_type, JS_FUNCTION_PROXY_TYPE);
+  __ B(eq, &shift_arguments);
+  __ Bind(&non_function);
+  __ Mov(x4, 2);  // Indicate non-function.
+
+  // 3c. 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.
+  // x0: actual number of arguments
+  // x1: function
+  // x4: call type (0: JS function, 1: function proxy, 2: non-function)
+  __ Sub(x10, x0, 1);
+  __ Poke(x1, Operand(x10, LSL, kXRegSizeInBytesLog2));
+
+  // 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.
+  // x0: actual number of arguments
+  // x1: function
+  // x4: call type (0: JS function, 1: function proxy, 2: non-function)
+  __ Bind(&shift_arguments);
+  { Label loop;
+    // Calculate the copy start address (destination). Copy end address is jssp.
+    __ Add(x11, jssp, Operand(x0, LSL, kPointerSizeLog2));
+    __ Sub(x10, x11, kPointerSize);
+
+    // TODO(all): Optimize to copy values 2 by 2?
+    __ Bind(&loop);
+    __ Ldr(x12, MemOperand(x10, -kPointerSize, PostIndex));
+    __ Str(x12, MemOperand(x11, -kPointerSize, PostIndex));
+    __ Cmp(x10, jssp);
+    __ B(ge, &loop);
+    // Adjust the actual number of arguments and remove the top element
+    // (which is a copy of the last argument).
+    __ Sub(x0, x0, 1);
+    __ Drop(1);
+  }
+
+  // 5a. Call non-function via tail call to CALL_NON_FUNCTION builtin,
+  //     or a function proxy via CALL_FUNCTION_PROXY.
+  // x0: actual number of arguments
+  // x1: function
+  // x4: call type (0: JS function, 1: function proxy, 2: non-function)
+  { Label function, non_proxy;
+    __ Cbz(x4, &function);
+    // Expected number of arguments is 0 for CALL_NON_FUNCTION.
+    __ Mov(x2, 0);
+    __ Cmp(x4, 1);
+    __ B(ne, &non_proxy);
+
+    __ Push(x1);  // Re-add proxy object as additional argument.
+    __ Add(x0, x0, 1);
+    __ GetBuiltinFunction(x1, Builtins::CALL_FUNCTION_PROXY);
+    __ Jump(masm->isolate()->builtins()->ArgumentsAdaptorTrampoline(),
+            RelocInfo::CODE_TARGET);
+
+    __ Bind(&non_proxy);
+    __ GetBuiltinFunction(x1, Builtins::CALL_NON_FUNCTION);
+    __ 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.
+  // x0: actual number of arguments
+  // x1: function
+  __ Ldr(x3, FieldMemOperand(x1, JSFunction::kSharedFunctionInfoOffset));
+  __ Ldrsw(x2,
+           FieldMemOperand(x3,
+             SharedFunctionInfo::kFormalParameterCountOffset));
+  Label dont_adapt_args;
+  __ Cmp(x2, x0);  // Check formal and actual parameter counts.
+  __ B(eq, &dont_adapt_args);
+  __ Jump(masm->isolate()->builtins()->ArgumentsAdaptorTrampoline(),
+          RelocInfo::CODE_TARGET);
+  __ Bind(&dont_adapt_args);
+
+  __ Ldr(x3, FieldMemOperand(x1, JSFunction::kCodeEntryOffset));
+  ParameterCount expected(0);
+  __ InvokeCode(x3, expected, expected, JUMP_FUNCTION, NullCallWrapper());
+}
+
+
+void Builtins::Generate_FunctionApply(MacroAssembler* masm) {
+  ASM_LOCATION("Builtins::Generate_FunctionApply");
+  const int kIndexOffset    =
+      StandardFrameConstants::kExpressionsOffset - (2 * kPointerSize);
+  const int kLimitOffset    =
+      StandardFrameConstants::kExpressionsOffset - (1 * kPointerSize);
+  const int kArgsOffset     =  2 * kPointerSize;
+  const int kReceiverOffset =  3 * kPointerSize;
+  const int kFunctionOffset =  4 * kPointerSize;
+
+  {
+    FrameScope frame_scope(masm, StackFrame::INTERNAL);
+
+    Register args = x12;
+    Register receiver = x14;
+    Register function = x15;
+
+    // Get the length of the arguments via a builtin call.
+    __ Ldr(function, MemOperand(fp, kFunctionOffset));
+    __ Ldr(args, MemOperand(fp, kArgsOffset));
+    __ Push(function, args);
+    __ InvokeBuiltin(Builtins::APPLY_PREPARE, CALL_FUNCTION);
+    Register argc = x0;
+
+    // Check the stack for overflow.
+    // We are not trying to catch interruptions (e.g. debug break and
+    // preemption) here, so the "real stack limit" is checked.
+    Label enough_stack_space;
+    __ LoadRoot(x10, Heap::kRealStackLimitRootIndex);
+    __ Ldr(function, MemOperand(fp, kFunctionOffset));
+    // Make x10 the space we have left. The stack might already be overflowed
+    // here which will cause x10 to become negative.
+    // TODO(jbramley): Check that the stack usage here is safe.
+    __ Sub(x10, jssp, x10);
+    // Check if the arguments will overflow the stack.
+    __ Cmp(x10, Operand(argc, LSR, kSmiShift - kPointerSizeLog2));
+    __ B(gt, &enough_stack_space);
+    // There is not enough stack space, so use a builtin to throw an appropriate
+    // error.
+    __ Push(function, argc);
+    __ InvokeBuiltin(Builtins::APPLY_OVERFLOW, CALL_FUNCTION);
+    // We should never return from the APPLY_OVERFLOW builtin.
+    if (__ emit_debug_code()) {
+      __ Unreachable();
+    }
+
+    __ Bind(&enough_stack_space);
+    // Push current limit and index.
+    __ Mov(x1, 0);  // Initial index.
+    __ Push(argc, x1);
+
+    Label push_receiver;
+    __ Ldr(receiver, MemOperand(fp, kReceiverOffset));
+
+    // Check that the function is a JS function. Otherwise it must be a proxy.
+    // When it is not the function proxy will be invoked later.
+    __ JumpIfNotObjectType(function, x10, x11, JS_FUNCTION_TYPE,
+                           &push_receiver);
+
+    // Change context eagerly to get the right global object if necessary.
+    __ Ldr(cp, FieldMemOperand(function, JSFunction::kContextOffset));
+    // Load the shared function info.
+    __ Ldr(x2, FieldMemOperand(function,
+                               JSFunction::kSharedFunctionInfoOffset));
+
+    // Compute and push the receiver.
+    // Do not transform the receiver for strict mode functions.
+    Label convert_receiver_to_object, use_global_receiver;
+    __ Ldr(w10, FieldMemOperand(x2, SharedFunctionInfo::kCompilerHintsOffset));
+    __ Tbnz(x10, SharedFunctionInfo::kStrictModeFunction, &push_receiver);
+    // Do not transform the receiver for native functions.
+    __ Tbnz(x10, SharedFunctionInfo::kNative, &push_receiver);
+
+    // Compute the receiver in non-strict mode.
+    __ JumpIfSmi(receiver, &convert_receiver_to_object);
+    __ JumpIfRoot(receiver, Heap::kNullValueRootIndex, &use_global_receiver);
+    __ JumpIfRoot(receiver, Heap::kUndefinedValueRootIndex,
+                  &use_global_receiver);
+
+    // Check if the receiver is already a JavaScript object.
+    STATIC_ASSERT(LAST_SPEC_OBJECT_TYPE == LAST_TYPE);
+    __ JumpIfObjectType(receiver, x10, x11, FIRST_SPEC_OBJECT_TYPE,
+                        &push_receiver, ge);
+
+    // Call a builtin to convert the receiver to a regular object.
+    __ Bind(&convert_receiver_to_object);
+    __ Push(receiver);
+    __ InvokeBuiltin(Builtins::TO_OBJECT, CALL_FUNCTION);
+    __ Mov(receiver, x0);
+    __ B(&push_receiver);
+
+    __ Bind(&use_global_receiver);
+    __ Ldr(x10, GlobalObjectMemOperand());
+    __ Ldr(receiver, FieldMemOperand(x10, GlobalObject::kGlobalReceiverOffset));
+
+    // Push the receiver
+    __ Bind(&push_receiver);
+    __ Push(receiver);
+
+    // Copy all arguments from the array to the stack.
+    Label entry, loop;
+    Register current = x0;
+    __ Ldr(current, MemOperand(fp, kIndexOffset));
+    __ B(&entry);
+
+    __ Bind(&loop);
+    // Load the current argument from the arguments array and push it.
+    // TODO(all): Couldn't we optimize this for JS arrays?
+
+    __ Ldr(x1, MemOperand(fp, kArgsOffset));
+    __ Push(x1, current);
+
+    // Call the runtime to access the property in the arguments array.
+    __ CallRuntime(Runtime::kGetProperty, 2);
+    __ Push(x0);
+
+    // Use inline caching to access the arguments.
+    __ Ldr(current, MemOperand(fp, kIndexOffset));
+    __ Add(current, current, Operand(Smi::FromInt(1)));
+    __ Str(current, MemOperand(fp, kIndexOffset));
+
+    // Test if the copy loop has finished copying all the elements from the
+    // arguments object.
+    __ Bind(&entry);
+    __ Ldr(x1, MemOperand(fp, kLimitOffset));
+    __ Cmp(current, x1);
+    __ B(ne, &loop);
+
+    // At the end of the loop, the number of arguments is stored in 'current',
+    // represented as a smi.
+
+    function = x1;  // From now on we want the function to be kept in x1;
+    __ Ldr(function, MemOperand(fp, kFunctionOffset));
+
+    // Call the function.
+    Label call_proxy;
+    ParameterCount actual(current);
+    __ SmiUntag(current);
+    __ JumpIfNotObjectType(function, x10, x11, JS_FUNCTION_TYPE, &call_proxy);
+    __ InvokeFunction(function, actual, CALL_FUNCTION, NullCallWrapper());
+    frame_scope.GenerateLeaveFrame();
+    __ Drop(3);
+    __ Ret();
+
+    // Call the function proxy.
+    __ Bind(&call_proxy);
+    // x0 : argc
+    // x1 : function
+    __ Push(function);  // Add function proxy as last argument.
+    __ Add(x0, x0, 1);
+    __ Mov(x2, 0);
+    __ GetBuiltinFunction(x1, Builtins::CALL_FUNCTION_PROXY);
+    __ Call(masm->isolate()->builtins()->ArgumentsAdaptorTrampoline(),
+            RelocInfo::CODE_TARGET);
+  }
+  __ Drop(3);
+  __ Ret();
+}
+
+
+static void EnterArgumentsAdaptorFrame(MacroAssembler* masm) {
+  __ SmiTag(x10, x0);
+  __ Mov(x11, Operand(Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR)));
+  __ Push(lr, fp);
+  __ Push(x11, x1, x10);
+  __ Add(fp, jssp,
+         StandardFrameConstants::kFixedFrameSizeFromFp + kPointerSize);
+}
+
+
+static void LeaveArgumentsAdaptorFrame(MacroAssembler* masm) {
+  // ----------- S t a t e -------------
+  //  -- x0 : result being passed through
+  // -----------------------------------
+  // Get the number of arguments passed (as a smi), tear down the frame and
+  // then drop the parameters and the receiver.
+  __ Ldr(x10, MemOperand(fp, -(StandardFrameConstants::kFixedFrameSizeFromFp +
+                               kPointerSize)));
+  __ Mov(jssp, fp);
+  __ Pop(fp, lr);
+  __ DropBySMI(x10, kXRegSizeInBytes);
+  __ Drop(1);
+}
+
+
+void Builtins::Generate_ArgumentsAdaptorTrampoline(MacroAssembler* masm) {
+  ASM_LOCATION("Builtins::Generate_ArgumentsAdaptorTrampoline");
+  // ----------- S t a t e -------------
+  //  -- x0 : actual number of arguments
+  //  -- x1 : function (passed through to callee)
+  //  -- x2 : expected number of arguments
+  // -----------------------------------
+
+  Label invoke, dont_adapt_arguments;
+
+  Label enough, too_few;
+  __ Ldr(x3, FieldMemOperand(x1, JSFunction::kCodeEntryOffset));
+  __ Cmp(x0, x2);
+  __ B(lt, &too_few);
+  __ Cmp(x2, SharedFunctionInfo::kDontAdaptArgumentsSentinel);
+  __ B(eq, &dont_adapt_arguments);
+
+  {  // Enough parameters: actual >= expected
+    EnterArgumentsAdaptorFrame(masm);
+
+    // Calculate copy start address into x10 and end address into x11.
+    // x0: actual number of arguments
+    // x1: function
+    // x2: expected number of arguments
+    // x3: code entry to call
+    __ Add(x10, fp, Operand(x0, LSL, kPointerSizeLog2));
+    // Adjust for return address and receiver
+    __ Add(x10, x10, 2 * kPointerSize);
+    __ Sub(x11, x10, Operand(x2, LSL, kPointerSizeLog2));
+
+    // Copy the arguments (including the receiver) to the new stack frame.
+    // x0: actual number of arguments
+    // x1: function
+    // x2: expected number of arguments
+    // x3: code entry to call
+    // x10: copy start address
+    // x11: copy end address
+
+    // TODO(all): Should we push values 2 by 2?
+    Label copy;
+    __ Bind(&copy);
+    __ Cmp(x10, x11);
+    __ Ldr(x12, MemOperand(x10, -kPointerSize, PostIndex));
+    __ Push(x12);
+    __ B(gt, &copy);
+
+    __ B(&invoke);
+  }
+
+  {  // Too few parameters: Actual < expected
+    __ Bind(&too_few);
+    EnterArgumentsAdaptorFrame(masm);
+
+    // Calculate copy start address into x10 and copy end address into x11.
+    // x0: actual number of arguments
+    // x1: function
+    // x2: expected number of arguments
+    // x3: code entry to call
+    // Adjust for return address.
+    __ Add(x11, fp, 1 * kPointerSize);
+    __ Add(x10, x11, Operand(x0, LSL, kPointerSizeLog2));
+    __ Add(x10, x10, 1 * kPointerSize);
+
+    // Copy the arguments (including the receiver) to the new stack frame.
+    // x0: actual number of arguments
+    // x1: function
+    // x2: expected number of arguments
+    // x3: code entry to call
+    // x10: copy start address
+    // x11: copy end address
+    Label copy;
+    __ Bind(&copy);
+    __ Ldr(x12, MemOperand(x10, -kPointerSize, PostIndex));
+    __ Push(x12);
+    __ Cmp(x10, x11);  // Compare before moving to next argument.
+    __ B(ne, &copy);
+
+    // Fill the remaining expected arguments with undefined.
+    // x0: actual number of arguments
+    // x1: function
+    // x2: expected number of arguments
+    // x3: code entry to call
+    __ LoadRoot(x10, Heap::kUndefinedValueRootIndex);
+    __ Sub(x11, fp, Operand(x2, LSL, kPointerSizeLog2));
+    // Adjust for the arguments adaptor frame and already pushed receiver.
+    __ Sub(x11, x11,
+           StandardFrameConstants::kFixedFrameSizeFromFp + (2 * kPointerSize));
+
+    // TODO(all): Optimize this to use ldp?
+    Label fill;
+    __ Bind(&fill);
+    __ Push(x10);
+    __ Cmp(jssp, x11);
+    __ B(ne, &fill);
+  }
+
+  // Arguments have been adapted. Now call the entry point.
+  __ Bind(&invoke);
+  __ Call(x3);
+
+  // Store offset of return address for deoptimizer.
+  masm->isolate()->heap()->SetArgumentsAdaptorDeoptPCOffset(masm->pc_offset());
+
+  // Exit frame and return.
+  LeaveArgumentsAdaptorFrame(masm);
+  __ Ret();
+
+  // Call the entry point without adapting the arguments.
+  __ Bind(&dont_adapt_arguments);
+  __ Jump(x3);
+}
+
+
+#undef __
+
+} }  // namespace v8::internal
+
+#endif  // V8_TARGET_ARCH_ARM