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

src/arm64/code-stubs-arm64.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_ARM64
 
 #include "src/bootstrapper.h"
 #include "src/code-stubs.h"
@@ skipping 3869 matching lines @@
                                   STRING_INDEX_IS_NUMBER, RECEIVER_IS_STRING);
   generator.GenerateFast(masm);
   __ Drop(3);
   __ Ret();
   generator.SkipSlow(masm, &runtime);
 }
 
 
 void ToNumberStub::Generate(MacroAssembler* masm) {
   // The ToNumber stub takes one argument in x0.
-  Label check_heap_number, call_builtin;
-  __ JumpIfNotSmi(x0, &check_heap_number);
+  Label not_smi;
+  __ JumpIfNotSmi(x0, &not_smi);
   __ Ret();
+  __ Bind(&not_smi);
 
-  __ bind(&check_heap_number);
-  __ JumpIfNotHeapNumber(x0, &call_builtin);
+  Label not_heap_number;
+  __ Ldr(x1, FieldMemOperand(x0, HeapObject::kMapOffset));
+  __ Ldrb(x1, FieldMemOperand(x1, Map::kInstanceTypeOffset));
+  // x0: object
+  // x1: instance type
+  __ Cmp(x1, HEAP_NUMBER_TYPE);
+  __ B(ne, &not_heap_number);
   __ Ret();
+  __ Bind(&not_heap_number);
 
-  __ bind(&call_builtin);
-  __ push(x0);
+  Label not_string, slow_string;
+  __ Cmp(x1, FIRST_NONSTRING_TYPE);
+  __ B(hs, &not_string);
+  // Check if string has a cached array index.
+  __ Ldr(x2, FieldMemOperand(x0, String::kHashFieldOffset));
+  __ Tst(x2, Operand(String::kContainsCachedArrayIndexMask));
+  __ B(ne, &slow_string);
+  __ IndexFromHash(x2, x0);
+  __ Ret();
+  __ Bind(&slow_string);
+  __ Push(x0);  // Push argument.
+  __ TailCallRuntime(Runtime::kStringToNumber, 1, 1);
+  __ Bind(&not_string);
+
+  Label not_oddball;
+  __ Cmp(x1, ODDBALL_TYPE);
+  __ B(ne, &not_oddball);
+  __ Ldr(x0, FieldMemOperand(x0, Oddball::kToNumberOffset));
+  __ Ret();
+  __ Bind(&not_oddball);
+
+  __ Push(x0);  // Push argument.
   __ InvokeBuiltin(Builtins::TO_NUMBER, JUMP_FUNCTION);
 }
 
 
 void StringHelper::GenerateFlatOneByteStringEquals(
     MacroAssembler* masm, Register left, Register right, Register scratch1,
     Register scratch2, Register scratch3) {
   DCHECK(!AreAliased(left, right, scratch1, scratch2, scratch3));
   Register result = x0;
   Register left_length = scratch1;
@@ skipping 1251 matching lines @@
                               MemOperand(fp, 6 * kPointerSize),
                               NULL);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM64