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

src/arm/code-stubs-arm.cc

Index: src/arm/code-stubs-arm.cc
diff --git a/src/arm/code-stubs-arm.cc b/src/arm/code-stubs-arm.cc
index 47df2a353e989c6f824bf69199d3c58f6bd0c62c..ef286bbe01585a7a1ad56d3e71c0b5fdc278233f 100644
--- a/src/arm/code-stubs-arm.cc
+++ b/src/arm/code-stubs-arm.cc
@@ -3181,18 +3181,43 @@ void SubStringStub::Generate(MacroAssembler* masm) {
 
 void ToNumberStub::Generate(MacroAssembler* masm) {
   // The ToNumber stub takes one argument in r0.
-  Label check_heap_number, call_builtin;
-  __ JumpIfNotSmi(r0, &check_heap_number);
+  Label not_smi;
+  __ JumpIfNotSmi(r0, &not_smi);
   __ Ret();
+  __ bind(&not_smi);
 
-  __ bind(&check_heap_number);
+  Label not_heap_number;
   __ ldr(r1, FieldMemOperand(r0, HeapObject::kMapOffset));
-  __ CompareRoot(r1, Heap::kHeapNumberMapRootIndex);
-  __ b(ne, &call_builtin);
+  __ ldrb(r1, FieldMemOperand(r1, Map::kInstanceTypeOffset));
+  // r0: object
+  // r1: instance type.
+  __ cmp(r1, Operand(HEAP_NUMBER_TYPE));
+  __ b(ne, &not_heap_number);
+  __ Ret();
+  __ bind(&not_heap_number);
+
+  Label not_string, slow_string;
+  __ cmp(r1, Operand(FIRST_NONSTRING_TYPE));
+  __ b(hs, &not_string);
+  // Check if string has a cached array index.
+  __ ldr(r2, FieldMemOperand(r0, String::kHashFieldOffset));
+  __ tst(r2, Operand(String::kContainsCachedArrayIndexMask));
+  __ b(ne, &slow_string);
+  __ IndexFromHash(r2, r0);
+  __ Ret();
+  __ bind(&slow_string);
+  __ push(r0);  // Push argument.
+  __ TailCallRuntime(Runtime::kStringToNumber, 1, 1);
+  __ bind(&not_string);
+
+  Label not_oddball;
+  __ cmp(r1, Operand(ODDBALL_TYPE));
+  __ b(ne, &not_oddball);
+  __ ldr(r0, FieldMemOperand(r0, Oddball::kToNumberOffset));
   __ Ret();
+  __ bind(&not_oddball);
 
-  __ bind(&call_builtin);
-  __ push(r0);
+  __ push(r0);  // Push argument.
   __ InvokeBuiltin(Builtins::TO_NUMBER, JUMP_FUNCTION);
 }