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Re: gcc 4.4.4 can freeze x86_64
On 15/03/11 05:33, Ian Lance Taylor wrote:
> "Wolfram R. Jarisch" <wolfram@cyber-inc.us> writes:
>
>> When compiling code with a total array size about equal (or slightly
>> larger) to the machine RAM the system freezes (here it is an x86_64 with
>> 24GB running RHEL 6). Redhat identified this as a problem with the
>> computation on the sha1sum on gcc 4.4.4 (case# 00387722). For some
>> reason the compiler tries to "work though the array" in its whole size
>> to compute a sha1sum.
>
> A Red Hat case number doesn't tell us anything useful, so I'm not sure
> exactly what the problem is. As far as I know, the compiler does not
> compute any SHA1 checksum. The linker does compute such a checksum if
> you pass the --build-id option. The linker is part of the GNU binutils;
> it is not part of the compiler. Linker bug reports should go to
> binutils@sourceware.org; see http://sourceware.org/binutils/ .
>
> That said, I think the linker just computes the checksum over the
> section contents of the output file. It has to generate that data
> anyhow, so I don't know why computing the checksum would make such a big
> difference in linker performance.
Maybe there's a bug that causes sha1sum to be iterated over all of BSS?
Actually, that may not even be a bug: it makes sense for the sha1sum to
be different if the size of BSS (and nothing else) changes.
Anyway, as you say, it's a binutils issue.
Andrew.