[runtime] Drop FIRST/LAST_NONCALLABLE_SPEC_OBJECT instance type range.

src/full-codegen/x64/full-codegen-x64.cc

Index: src/full-codegen/x64/full-codegen-x64.cc
diff --git a/src/full-codegen/x64/full-codegen-x64.cc b/src/full-codegen/x64/full-codegen-x64.cc
index 21dd3e87b4e7ba19e44d7bf43b26963d63dc124b..1b65345f29b2cc2a95ad87e018d47d7e1128c4e7 100644
--- a/src/full-codegen/x64/full-codegen-x64.cc
+++ b/src/full-codegen/x64/full-codegen-x64.cc
@@ -3190,49 +3190,40 @@ void FullCodeGenerator::EmitClassOf(CallRuntime* expr) {
 
   VisitForAccumulatorValue(args->at(0));
 
-  // If the object is a smi, we return null.
-  __ JumpIfSmi(rax, &null);
-
-  // Check that the object is a JS object but take special care of JS
-  // functions to make sure they have 'Function' as their class.
-  // Assume that there are only two callable types, and one of them is at
-  // either end of the type range for JS object types. Saves extra comparisons.
-  STATIC_ASSERT(NUM_OF_CALLABLE_SPEC_OBJECT_TYPES == 2);
+  // If the object is not a JSReceiver, we return null.
+  __ JumpIfSmi(rax, &null, Label::kNear);
+  STATIC_ASSERT(LAST_JS_RECEIVER_TYPE == LAST_TYPE);
   __ CmpObjectType(rax, FIRST_JS_RECEIVER_TYPE, rax);
-  // Map is now in rax.
-  __ j(below, &null);
+  __ j(below, &null, Label::kNear);
 
-  __ CmpInstanceType(rax, LAST_JS_RECEIVER_TYPE);
-  STATIC_ASSERT(LAST_NONCALLABLE_SPEC_OBJECT_TYPE ==
-                LAST_JS_RECEIVER_TYPE - 1);
-  __ j(equal, &function);
-  // Assume that there is no larger type.
-  STATIC_ASSERT(LAST_NONCALLABLE_SPEC_OBJECT_TYPE == LAST_TYPE - 1);
+  // Return 'Function' for JSFunction objects.
+  __ CmpInstanceType(rax, JS_FUNCTION_TYPE);
+  __ j(equal, &function, Label::kNear);
 
   // Check if the constructor in the map is a JS function.
   __ GetMapConstructor(rax, rax, rbx);
   __ CmpInstanceType(rbx, JS_FUNCTION_TYPE);
-  __ j(not_equal, &non_function_constructor);
+  __ j(not_equal, &non_function_constructor, Label::kNear);
 
   // rax now contains the constructor function. Grab the
   // instance class name from there.
   __ movp(rax, FieldOperand(rax, JSFunction::kSharedFunctionInfoOffset));
   __ movp(rax, FieldOperand(rax, SharedFunctionInfo::kInstanceClassNameOffset));
-  __ jmp(&done);
+  __ jmp(&done, Label::kNear);
+
+  // Non-JS objects have class null.
+  __ bind(&null);
+  __ LoadRoot(rax, Heap::kNullValueRootIndex);
+  __ jmp(&done, Label::kNear);
 
   // Functions have class 'Function'.
   __ bind(&function);
-  __ Move(rax, isolate()->factory()->Function_string());
-  __ jmp(&done);
+  __ LoadRoot(rax, Heap::kFunction_stringRootIndex);
+  __ jmp(&done, Label::kNear);
 
   // Objects with a non-function constructor have class 'Object'.
   __ bind(&non_function_constructor);
-  __ Move(rax, isolate()->factory()->Object_string());
-  __ jmp(&done);
-
-  // Non-JS objects have class null.
-  __ bind(&null);
-  __ LoadRoot(rax, Heap::kNullValueRootIndex);
+  __ LoadRoot(rax, Heap::kObject_stringRootIndex);
 
   // All done.
   __ bind(&done);