Turn ToNumberStub into a PlatformCodeStub again.

src/x64/code-stubs-x64.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/bootstrapper.h"
 #include "src/code-stubs.h"
@@ skipping 3104 matching lines @@
   // rdx: from index (smi)
   StringCharAtGenerator generator(rax, rdx, rcx, rax, &runtime, &runtime,
                                   &runtime, STRING_INDEX_IS_NUMBER,
                                   RECEIVER_IS_STRING);
   generator.GenerateFast(masm);
   __ ret(SUB_STRING_ARGUMENT_COUNT * kPointerSize);
   generator.SkipSlow(masm, &runtime);
 }
 
 
+void ToNumberStub::Generate(MacroAssembler* masm) {
+  // The ToNumber stub takes one argument in rax.
+  Label check_heap_number, call_builtin;
+  __ JumpIfNotSmi(rax, &check_heap_number, Label::kNear);
+  __ Ret();
+
+  __ bind(&check_heap_number);
+  __ CompareRoot(FieldOperand(rax, HeapObject::kMapOffset),
+                 Heap::kHeapNumberMapRootIndex);
+  __ j(not_equal, &call_builtin, Label::kNear);
+  __ Ret();
+
+  __ bind(&call_builtin);
+  __ popq(rcx);  // Pop return address.
+  __ pushq(rax);
+  __ pushq(rcx);  // Push return address.
+  __ InvokeBuiltin(Builtins::TO_NUMBER, JUMP_FUNCTION);
+}
+
+
 void StringHelper::GenerateFlatOneByteStringEquals(MacroAssembler* masm,
                                                    Register left,
                                                    Register right,
                                                    Register scratch1,
                                                    Register scratch2) {
   Register length = scratch1;
 
   // Compare lengths.
   Label check_zero_length;
   __ movp(length, FieldOperand(left, String::kLengthOffset));
@@ skipping 1572 matching lines @@
                               return_value_operand,
                               NULL);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64