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

src/mips/lithium-codegen-mips.cc

Index: src/mips/lithium-codegen-mips.cc
diff --git a/src/mips/lithium-codegen-mips.cc b/src/mips/lithium-codegen-mips.cc
index 5586ed1ab264e7dd1f1a68ed40a313ff71e370e3..c98da629475efb8275e07af656779109583dbffa 100644
--- a/src/mips/lithium-codegen-mips.cc
+++ b/src/mips/lithium-codegen-mips.cc
@@ -2544,30 +2544,20 @@ void LCodeGen::EmitClassOfTest(Label* is_true,
 
   __ JumpIfSmi(input, is_false);
 
-  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);
+  STATIC_ASSERT(LAST_JS_RECEIVER_TYPE == LAST_TYPE);
+  __ GetObjectType(input, temp, temp2);
+  __ Branch(is_false, lt, temp2, Operand(FIRST_JS_RECEIVER_TYPE));
 
-    __ 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));
+  // 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));
   } else {
-    // 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));
+    __ Branch(is_false, ne, temp2, Operand(zero_reg));
   }
 
-  // Now we are in the FIRST-LAST_NONCALLABLE_SPEC_OBJECT_TYPE range.
+  // Now we are in the FIRST-LAST_JS_RECEIVER_TYPE range.
   // Check if the constructor in the map is a function.
   Register instance_type = scratch1();
   DCHECK(!instance_type.is(temp));