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

src/x64/lithium-codegen-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.
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/base/bits.h"
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
 #include "src/cpu-profiler.h"
@@ skipping 2554 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);
-  __ CmpObjectType(input, FIRST_JS_RECEIVER_TYPE, temp);
-  __ j(below, is_false);
-
-  // Objects with [[Call]] have class 'Function'.
-  __ testb(FieldOperand(temp, Map::kBitFieldOffset),
-           Immediate(1 << Map::kIsCallable));
   if (String::Equals(isolate()->factory()->Function_string(), class_name)) {
-    __ j(not_zero, is_true);
+    // 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);
+    __ CmpObjectType(input, FIRST_SPEC_OBJECT_TYPE, temp);
+    __ j(below, is_false);
+    __ j(equal, is_true);
+    __ CmpInstanceType(temp, LAST_SPEC_OBJECT_TYPE);
+    __ j(equal, is_true);
   } else {
-    __ j(not_zero, is_false);
+    // 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.
+    __ movp(temp, FieldOperand(input, HeapObject::kMapOffset));
+    __ movzxbl(temp2, FieldOperand(temp, Map::kInstanceTypeOffset));
+    __ subp(temp2, Immediate(FIRST_NONCALLABLE_SPEC_OBJECT_TYPE));
+    __ cmpp(temp2, Immediate(LAST_NONCALLABLE_SPEC_OBJECT_TYPE -
+                             FIRST_NONCALLABLE_SPEC_OBJECT_TYPE));
+    __ j(above, is_false);
   }
 
-  // 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.
   __ GetMapConstructor(temp, temp, kScratchRegister);
 
   // Objects with a non-function constructor have class 'Object'.
   __ CmpInstanceType(kScratchRegister, JS_FUNCTION_TYPE);
   if (String::Equals(class_name, isolate()->factory()->Object_string())) {
     __ j(not_equal, is_true);
   } else {
     __ j(not_equal, is_false);
   }
@@ skipping 3335 matching lines @@
   RecordSafepoint(Safepoint::kNoLazyDeopt);
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64