[turbofan] Remove the no-context hack for JSToNumber.

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 3151 matching lines @@
                                   &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);
+  Label not_smi;
+  __ JumpIfNotSmi(rax, &not_smi, Label::kNear);
   __ Ret();
+  __ bind(&not_smi);
 
-  __ bind(&check_heap_number);
+  Label not_heap_number;
   __ CompareRoot(FieldOperand(rax, HeapObject::kMapOffset),
                  Heap::kHeapNumberMapRootIndex);
-  __ j(not_equal, &call_builtin, Label::kNear);
+  __ j(not_equal, &not_heap_number, Label::kNear);
   __ Ret();
+  __ bind(&not_heap_number);
 
-  __ bind(&call_builtin);
-  __ popq(rcx);  // Pop return address.
-  __ pushq(rax);
-  __ pushq(rcx);  // Push return address.
+  Label not_string, slow_string;
+  __ CmpObjectType(rax, FIRST_NONSTRING_TYPE, rdi);
+  // rax: object
+  // rdi: object map
+  __ j(above_equal, &not_string, Label::kNear);
+  // Check if string has a cached array index.
+  __ testl(FieldOperand(rax, String::kHashFieldOffset),
+           Immediate(String::kContainsCachedArrayIndexMask));
+  __ j(not_zero, &slow_string, Label::kNear);
+  __ movl(rax, FieldOperand(rax, String::kHashFieldOffset));
+  __ IndexFromHash(rax, rax);
+  __ Ret();
+  __ bind(&slow_string);
+  __ PopReturnAddressTo(rcx);     // Pop return address.
+  __ Push(rax);                   // Push argument.
+  __ PushReturnAddressFrom(rcx);  // Push return address.
+  __ TailCallRuntime(Runtime::kStringToNumber, 1, 1);
+  __ bind(&not_string);
+
+  Label not_oddball;
+  __ CmpInstanceType(rdi, ODDBALL_TYPE);
+  __ j(not_equal, &not_oddball, Label::kNear);
+  __ movp(rax, FieldOperand(rax, Oddball::kToNumberOffset));
+  __ Ret();
+  __ bind(&not_oddball);
+
+  __ PopReturnAddressTo(rcx);     // Pop return address.
+  __ Push(rax);                   // Push argument.
+  __ PushReturnAddressFrom(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;
@@ skipping 1576 matching lines @@
                               return_value_operand,
                               NULL);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64