Fix error introduced in version 3820

src/arm/stub-cache-arm.cc

 // Copyright 2006-2009 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 171 matching lines @@
   // Check that the object is a JS array.
   __ CompareObjectType(receiver, scratch, scratch, JS_ARRAY_TYPE);
   __ b(ne, miss_label);
 
   // Load length directly from the JS array.
   __ ldr(r0, FieldMemOperand(receiver, JSArray::kLengthOffset));
   __ Ret();
 }
 
 
-// Generate code to check if an object is a string.  If the object is
-// a string, the map's instance type is left in the scratch1 register.
+// Generate code to check if an object is a string.  If the object is a
+// heap object, its map's instance type is left in the scratch1 register.
+// If this is not needed, scratch1 and scratch2 may be the same register.
 static void GenerateStringCheck(MacroAssembler* masm,
                                 Register receiver,
                                 Register scratch1,
                                 Register scratch2,
                                 Label* smi,
                                 Label* non_string_object) {
   // Check that the receiver isn't a smi.
   __ tst(receiver, Operand(kSmiTagMask));
   __ b(eq, smi);
 
   // Check that the object is a string.
   __ ldr(scratch1, FieldMemOperand(receiver, HeapObject::kMapOffset));
   __ ldrb(scratch1, FieldMemOperand(scratch1, Map::kInstanceTypeOffset));
   __ and_(scratch2, scratch1, Operand(kIsNotStringMask));
   // The cast is to resolve the overload for the argument of 0x0.
   __ cmp(scratch2, Operand(static_cast<int32_t>(kStringTag)));
   __ b(ne, non_string_object);
 }
 
 
 // Generate code to load the length from a string object and return the length.
 // If the receiver object is not a string or a wrapped string object the
 // execution continues at the miss label. The register containing the
 // receiver is potentially clobbered.
 void StubCompiler::GenerateLoadStringLength(MacroAssembler* masm,
                                             Register receiver,
                                             Register scratch1,
                                             Register scratch2,
                                             Label* miss) {
-  Label check_string, check_wrapper;
+  Label check_wrapper;
 
-  __ bind(&check_string);
   // Check if the object is a string leaving the instance type in the
   // scratch1 register.
-  GenerateStringCheck(masm, receiver, scratch1, scratch2,
-                      miss, &check_wrapper);
+  GenerateStringCheck(masm, receiver, scratch1, scratch2, miss, &check_wrapper);
 
   // Load length directly from the string.
   __ ldr(r0, FieldMemOperand(receiver, String::kLengthOffset));
   __ mov(r0, Operand(r0, LSL, kSmiTagSize));
   __ Ret();
 
   // Check if the object is a JSValue wrapper.
   __ bind(&check_wrapper);
   __ cmp(scratch1, Operand(JS_VALUE_TYPE));
   __ b(ne, miss);
 
-  // Unwrap the value in place and check if the wrapped value is a string.
-  __ ldr(receiver, FieldMemOperand(receiver, JSValue::kValueOffset));
-  __ b(&check_string);
+  // Unwrap the value and check if the wrapped value is a string.
+  __ ldr(scratch1, FieldMemOperand(receiver, JSValue::kValueOffset));
+  GenerateStringCheck(masm, scratch1, scratch2, scratch2, miss, miss);
+  __ ldr(r0, FieldMemOperand(scratch1, String::kLengthOffset));
+  __ mov(r0, Operand(r0, LSL, kSmiTagSize));
+  __ Ret();
 }
 
 
 void StubCompiler::GenerateLoadFunctionPrototype(MacroAssembler* masm,
                                                  Register receiver,
                                                  Register scratch1,
                                                  Register scratch2,
                                                  Label* miss_label) {
   __ TryGetFunctionPrototype(receiver, scratch1, scratch2, miss_label);
   __ mov(r0, scratch1);
@@ skipping 1620 matching lines @@
   __ Jump(generic_construct_stub, RelocInfo::CODE_TARGET);
 
   // Return the generated code.
   return GetCode();
 }
 
 
 #undef __
 
 } }  // namespace v8::internal