On Mon, Nov 01, 2010 at 09:04:12AM -0400, Tom "spot" Callaway wrote:
On 10/30/2010 06:01 AM, Richard W.M. Jones wrote:
> On Sat, Oct 30, 2010 at 02:24:02AM -0400, Jon Stanley wrote:
>> I noticed on my Fedora 13 box that in the RPM macro %__global_cflags
>> that -frecord-gcc-switches is missing, which is a nifty compiler
>> feature that will record the flags passed to gcc in a section in the
>> object file, thus aiding in the "how in the world was this compiled?"
>> problem. An example:
>>
>> [jstanley@hawtness ~]$ gcc -O2 -frecord-gcc-switches -g -o hello hello.c
>> [jstanley@hawtness ~]$ readelf -p .GCC.command.line hello
>>
>> String dump of section '.GCC.command.line':
>> [ 0] hello.c
>> [ 8] -mtune=generic
>> [ 17] -g
>> [ 1a] -O2
>> [ 1e] -frecord-gcc-switches
>>
>> What do folks think about adding this as a default? Any reason not to
>> (other than possibly a few bytes extra in the object files)?
>
> +1
>
> I think would also catch those cases where some gcc flag is found to
> break code generation. You reasonably see which binaries were
> affected.
I agree. Unless there is a notable performance cost in this, I say we
should go for it.
-frecord-gcc-switches is unfortunately pretty much useless, see
http://gcc.gnu.org/PR32998. Please don't add it, we want something actually
usable, not this option.
Jakub