Request for reviews (XS): 7047069: Array can dynamically change size when assigned to an object field

[Tom Rodriguez]

On May 27, 2011, at 11:51 AM, Vladimir Kozlov wrote:

> http://cr.openjdk.java.net/~kvn/7047069/webrev
> 
> Fixed 7047069: Array can dynamically change size when assigned to an object field
> 
> I lost my faith in our testing :( This broken code was there for more then 3 years and nobody hit it?
> The initialization of a newly-allocated array with arraycopy is broken when src and dest offsets are not constants. The typo in the code convert not constant offsets to constant 8: 12 + (-1)*4. So we generates copy from offset 8 which is array length and overwrite it and the rest of the beginning of the array.

I don't really like the find_int_con idiom all that much and the usage here is too clever.  It's much less clear than:

if (src_offset->Opcode() == Op_ConI || dest_offset->Opcode() == Op_ConI)
  return;

intptr_t src_off  = abase + ((intptr_t) src_offset->find_int_con()  << scale);
intptr_t dest_off = abase + ((intptr_t) dest_offset->find_int_con() << scale);

Anyway, your fix is good.

tom

> 
> Added regression test.