Fix bug in the top-level compiler: write barrier for assignments to context slots:...

src/arm/fast-codegen-arm.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 844 matching lines @@
 
         // RecordWrite may destroy all its register arguments.
         if (expr->context() == Expression::kValue) {
           __ push(r1);
         } else if (expr->context() != Expression::kEffect) {
           __ mov(r3, r1);
         }
         int offset = FixedArray::kHeaderSize + slot->index() * kPointerSize;
 
         // Update the write barrier for the array store with r0 as the scratch
-        // register.  Skip the write barrier if r0 is a smi.
+        // register.  Skip the write barrier if the value written (r1) is a smi.
         // The smi test is part of RecordWrite on other platforms, not on arm.
         Label exit;
-        __ tst(r0, Operand(kSmiTagMask));
+        __ tst(r1, Operand(kSmiTagMask));
         __ b(eq, &exit);
 
         __ mov(r2, Operand(offset));
         __ RecordWrite(r0, r2, r1);
         __ bind(&exit);
         if (expr->context() != Expression::kEffect &&
             expr->context() != Expression::kValue) {
         Move(expr->context(), r3);
         }
         break;
@@ skipping 684 matching lines @@
   true_label_ = saved_true;
   false_label_ = saved_false;
   // Convert current context to test context: End post-test code.
 }
 
 
 #undef __
 
 
 } }  // namespace v8::internal