Change the special handling of typeof comparisons to strings for...

src/x64/codegen-x64.cc

 // Copyright 2009 the V8 project authors. All rights reserved.
 // 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 3477 matching lines @@
       __ testb(FieldOperand(kScratchRegister, Map::kBitFieldOffset),
                Immediate(1 << Map::kIsUndetectable));
       answer.Unuse();
       destination()->Split(not_zero);
 
     } else if (check->Equals(Heap::function_symbol())) {
       Condition is_smi = masm_->CheckSmi(answer.reg());
       destination()->false_target()->Branch(is_smi);
       frame_->Spill(answer.reg());
       __ CmpObjectType(answer.reg(), JS_FUNCTION_TYPE, answer.reg());
+      destination()->true_target()->Branch(equal);
+      // Regular expressions are callable so typeof == 'function'.
+      __ CmpInstanceType(answer.reg(), JS_REGEXP_TYPE);
       answer.Unuse();
       destination()->Split(equal);
 
     } else if (check->Equals(Heap::object_symbol())) {
       Condition is_smi = masm_->CheckSmi(answer.reg());
       destination()->false_target()->Branch(is_smi);
       __ CompareRoot(answer.reg(), Heap::kNullValueRootIndex);
       destination()->true_target()->Branch(equal);
 
+      // Regular expressions are typeof == 'function', not 'object'.
+      __ CmpObjectType(answer.reg(), JS_REGEXP_TYPE, kScratchRegister);
+      destination()->false_target()->Branch(equal);
+
       // It can be an undetectable object.
-      __ movq(kScratchRegister,
-              FieldOperand(answer.reg(), HeapObject::kMapOffset));
       __ testb(FieldOperand(kScratchRegister, Map::kBitFieldOffset),
                Immediate(1 << Map::kIsUndetectable));
       destination()->false_target()->Branch(not_zero);
       __ CmpInstanceType(kScratchRegister, FIRST_JS_OBJECT_TYPE);
       destination()->false_target()->Branch(below);
       __ CmpInstanceType(kScratchRegister, LAST_JS_OBJECT_TYPE);
       answer.Unuse();
       destination()->Split(below_equal);
     } else {
       // Uncommon case: typeof testing against a string literal that is
@@ skipping 4322 matching lines @@
   masm.GetCode(&desc);
   // Call the function from C++.
   return FUNCTION_CAST<ModuloFunction>(buffer);
 }
 
 #endif
 
 #undef __
 
 } }  // namespace v8::internal