non-deterministic as

[H.J. Lu]

On Thu, May 21, 2009 at 6:06 AM, chenyang <chenyang.cq@gmail.com> wrote:
> Hi everyone,
>
> I found a very strange problem of "as" when I was building gcc-4.3.3.
> I got a "Bootstrap comparison failure!", when means that some .o files
>  were not identical between stage2 and stage3. However, it turns out that
> the problem was introduced by "as" not gcc itself. For some .s files, as
> will produce a different .o file each time it is invoked with the same .s file:
>
>> as  -V -Qy -o obj1.o testtree.s
> GNU assembler version 2.19 (x86_64-unknown-linux-gnu) using BFD
> version (GNU Binutils) 2.19
>> as  -V -Qy -o obj2.o testtree.s
> GNU assembler version 2.19 (x86_64-unknown-linux-gnu) using BFD
> version (GNU Binutils) 2.19
>> ll obj*.o
> -rw-r--r--  1 tester users 87360 2009-05-21 20:37 obj1.o
> -rw-r--r--  1 tester users 87360 2009-05-21 20:37 obj2.o
>> cmp -i 16 obj1.o obj2.o
> obj1.o obj2.o differ: byte 66006, line 132
>

You can compare outputs from "objdump -drw",  "objump -s" as well
as "readelf -a" to see where/what the difference is.

-- 
H.J.