Add array bound checks to code generated for SwapElements. This fixes a bug t...

src/arm/codegen-arm.cc

 // Copyright 2010 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
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@@ skipping 5574 matching lines @@
   // Smi-tagging is equivalent to multiplying by 2.
   STATIC_ASSERT(kSmiTag == 0);
   STATIC_ASSERT(kSmiTagSize == 1);
 
   // Check that both indices are smis.
   __ mov(tmp2, index1);
   __ orr(tmp2, tmp2, index2);
   __ tst(tmp2, Operand(kSmiTagMask));
   deferred->Branch(nz);
 
+  // Check that both indices are valid.
+  __ ldr(tmp2, FieldMemOperand(object, JSArray::kLengthOffset));
+  __ cmp(tmp2, index1);
+  deferred->Branch(le);
+  __ cmp(tmp2, index2);

[Lasse Reichstein, 2010/12/15 08:34:55]

You might consider making the second compare conditional and only having one
branch. I.e.:
 __ cmp(tmp2, index1);
 __ cmp(tmp2, index2, gt);
 deferred->Branch(le);
I doubt it's faster, but it's a little smaller.

[Karl Klose, 2010/12/15 09:11:45]

Done.

+  deferred->Branch(le);
+
   // Bring the offsets into the fixed array in tmp1 into index1 and
   // index2.
   __ mov(tmp2, Operand(FixedArray::kHeaderSize - kHeapObjectTag));
   __ add(index1, tmp2, Operand(index1, LSL, kPointerSizeLog2 - kSmiTagSize));
   __ add(index2, tmp2, Operand(index2, LSL, kPointerSizeLog2 - kSmiTagSize));
 
   // Swap elements.
   Register tmp3 = object;
   object = no_reg;
   __ ldr(tmp3, MemOperand(tmp1, index1));
@@ skipping 1759 matching lines @@
                BinaryOpIC::GetName(runtime_operands_type_));
   return name_;
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM