Re: 8.1 Release Candidate 1 Coming ...

Is this issue only on AIX 5.3 ML1 thru ML 3?
Does the build work fine with 5.2 (ALL MLs)?



On 10/31/05, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Chris Browne <cbbrowne@acm.org> writes:
> > tgl@sss.pgh.pa.us (Tom Lane) writes:
> >> (My guess is that the problem is a compiler or libc bug anyway,
> >> given that one report says that replacing a memcpy call with an
> >> equivalent loop makes the failure go away.)
>
> > It seems unlikely to be a compiler bug as the same issue has been
> > reported with both GCC and IBM XLC.  I could believe it being a libc
> > bug...
>
> As best I can tell after poking at it on Stefan's machine, it's a linker
> bug, or else there is something strange about memcpy as compared to,
> say, memcmp.  A function pointer to memcmp works, a function pointer to
> memcpy contains a bogus value that points entirely outside the program's
> address space.  This despite the assembly code that generates them
> looking just the same in both cases, viz
>
> LC..12:
>         .tc memcmp[TC],memcmp[DS]
> LC..14:
>         .tc memcpy[TC],memcpy[DS]
>
> Even more interesting, if you start the postmaster under gdb and examine
> the pointer, then set a breakpoint at "main" and say "run", by the time
> control arrives at main() the bogus value has changed to a different
> bogus value.  So something in the basic C runtime support is frobbing it
> --- incorrectly :-(.  I think all the signs point to incorrect
> relocation data generated by the linker, though I have no idea why only
> memcpy would be affected.
>
> > It would be terribly disappointing to have to report both internally
> > and externally that AIX 5.3 is not a usable platform for recent
> > releases of PostgreSQL...
>
> According to Stefan it broke between 5.3ML1 and 5.3ML3.  I suggest
> filing a defect report with IBM.  We're not going to stop using memcpy
> because one version of one platform is broken.
>
>                         regards, tom lane
>
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