Revert of [es5] Class of object is "Function" if object has [[Call]].

src/mips/lithium-codegen-mips.cc

 // Copyright 2012 the V8 project authors. All rights reserved.7
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 2526 matching lines @@
                                Handle<String>class_name,
                                Register input,
                                Register temp,
                                Register temp2) {
   DCHECK(!input.is(temp));
   DCHECK(!input.is(temp2));
   DCHECK(!temp.is(temp2));
 
   __ JumpIfSmi(input, is_false);
 
-  STATIC_ASSERT(LAST_JS_RECEIVER_TYPE == LAST_TYPE);
-  __ GetObjectType(input, temp, temp2);
-  __ Branch(is_false, lt, temp2, Operand(FIRST_JS_RECEIVER_TYPE));
+  if (String::Equals(isolate()->factory()->Function_string(), class_name)) {
+    // Assuming the following assertions, we can use the same compares to test
+    // for both being a function type and being in the object type range.
+    STATIC_ASSERT(NUM_OF_CALLABLE_SPEC_OBJECT_TYPES == 2);
+    STATIC_ASSERT(FIRST_NONCALLABLE_SPEC_OBJECT_TYPE ==
+                  FIRST_SPEC_OBJECT_TYPE + 1);
+    STATIC_ASSERT(LAST_NONCALLABLE_SPEC_OBJECT_TYPE ==
+                  LAST_SPEC_OBJECT_TYPE - 1);
+    STATIC_ASSERT(LAST_SPEC_OBJECT_TYPE == LAST_TYPE);
 
-  // Objects with [[Call]] have class 'Function'.
-  __ lbu(temp2, FieldMemOperand(temp, Map::kBitFieldOffset));
-  __ And(temp2, temp2, Operand(1 << Map::kIsCallable));
-  if (String::Equals(isolate()->factory()->Function_string(), class_name)) {
-    __ Branch(is_true, ne, temp2, Operand(zero_reg));
+    __ GetObjectType(input, temp, temp2);
+    __ Branch(is_false, lt, temp2, Operand(FIRST_SPEC_OBJECT_TYPE));
+    __ Branch(is_true, eq, temp2, Operand(FIRST_SPEC_OBJECT_TYPE));
+    __ Branch(is_true, eq, temp2, Operand(LAST_SPEC_OBJECT_TYPE));
   } else {
-    __ Branch(is_false, ne, temp2, Operand(zero_reg));
+    // Faster code path to avoid two compares: subtract lower bound from the
+    // actual type and do a signed compare with the width of the type range.
+    __ GetObjectType(input, temp, temp2);
+    __ Subu(temp2, temp2, Operand(FIRST_NONCALLABLE_SPEC_OBJECT_TYPE));
+    __ Branch(is_false, gt, temp2, Operand(LAST_NONCALLABLE_SPEC_OBJECT_TYPE -
+                                           FIRST_NONCALLABLE_SPEC_OBJECT_TYPE));
   }
 
-  // Now we are in the FIRST-LAST_JS_RECEIVER_TYPE range.
+  // Now we are in the FIRST-LAST_NONCALLABLE_SPEC_OBJECT_TYPE range.
   // Check if the constructor in the map is a function.
   Register instance_type = scratch1();
   DCHECK(!instance_type.is(temp));
   __ GetMapConstructor(temp, temp, temp2, instance_type);
 
   // Objects with a non-function constructor have class 'Object'.
   if (String::Equals(class_name, isolate()->factory()->Object_string())) {
     __ Branch(is_true, ne, instance_type, Operand(JS_FUNCTION_TYPE));
   } else {
     __ Branch(is_false, ne, instance_type, Operand(JS_FUNCTION_TYPE));
@@ skipping 3348 matching lines @@
   __ Push(at, ToRegister(instr->function()));
   CallRuntime(Runtime::kPushBlockContext, 2, instr);
   RecordSafepoint(Safepoint::kNoLazyDeopt);
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8