Fix a potential crash bug in keyed calls for non-string keys.

src/arm/macro-assembler-arm.cc

 // Copyright 2011 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 911 matching lines @@
                                             Label* fail) {
   ldrb(scratch, FieldMemOperand(map, Map::kInstanceTypeOffset));
   cmp(scratch, Operand(FIRST_JS_OBJECT_TYPE));
   b(lt, fail);
   cmp(scratch, Operand(LAST_JS_OBJECT_TYPE));
   b(gt, fail);
 }
 
 
 void MacroAssembler::IsObjectJSStringType(Register object,
-                                           Register scratch,
-                                           Label* fail) {
+                                          Register scratch,
+                                          Label* fail) {
   ASSERT(kNotStringTag != 0);
 
   ldr(scratch, FieldMemOperand(object, HeapObject::kMapOffset));
   ldrb(scratch, FieldMemOperand(scratch, Map::kInstanceTypeOffset));
   tst(scratch, Operand(kIsNotStringMask));
   b(ne, fail);
 }
 
 
 #ifdef ENABLE_DEBUGGER_SUPPORT
@@ skipping 1171 matching lines @@
 }
 
 
 void MacroAssembler::AbortIfNotSmi(Register object) {
   STATIC_ASSERT(kSmiTag == 0);
   tst(object, Operand(kSmiTagMask));
   Assert(eq, "Operand is not smi");
 }
 
 
+void MacroAssembler::AbortIfNotString(Register object) {
+  STATIC_ASSERT(kSmiTag == 0);
+  tst(object, Operand(kSmiTagMask));
+  Assert(ne, "Operand is not a string");
+  push(object);
+  ldr(object, FieldMemOperand(object, HeapObject::kMapOffset));
+  CompareInstanceType(object, object, FIRST_NONSTRING_TYPE);
+  pop(object);
+  Assert(lo, "Operand is not a string");
+}
+
+
+
 void MacroAssembler::AbortIfNotRootValue(Register src,
                                          Heap::RootListIndex root_value_index,
                                          const char* message) {
   ASSERT(!src.is(ip));
   LoadRoot(ip, root_value_index);
   cmp(src, ip);
   Assert(eq, message);
 }
 
 
@@ skipping 288 matching lines @@
 void CodePatcher::EmitCondition(Condition cond) {
   Instr instr = Assembler::instr_at(masm_.pc_);
   instr = (instr & ~kCondMask) | cond;
   masm_.emit(instr);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM