On Wed, Nov 21, 2012 at 8:56 AM, Paolo Bonzini <bonz...@gnu.org> wrote: > Il 14/11/2012 15:27, Ian Lance Taylor ha scritto: >> On Wed, Nov 14, 2012 at 5:36 AM, Richard Earnshaw <rearn...@arm.com> wrote: >>> On 13/11/12 14:56, Ian Lance Taylor wrote: >>>> >>>> Currently -fPIC -fPIE seems to be the same as -fPIE. Unfortunately, >>>> -fPIE -fPIC also seems to be the same as -fPIE. It seems to me that, >>>> as is usual with conflicting options, we should use the one that >>>> appears last on the command line. >>>> >>>> Do we have an existing mechanism in options processing for one option >>>> to turn off another, where the options are not exact inverses? I >>>> looked for one but I didn't see one. There is support for that for >>>> options with the Mask property, but I don't see it for non-target >>>> options. >>> >>> pic and pie are mostly the same, but the pre-emption rules are different. >>> For fpie we don't have to permit pre-emption of global definitions. >>> >>> I hope we don't loose that distinction. >> >> No, of course not. All I'm talking about here is option processing >> when both -fPIC and -fPIE are provided. There is no change to the >> normal case of providing just -fPIC or just -fPIE. > > I think both -fPIC -fPIE and -fPIE -fPIC should be the same as -fPIC. > > The main advantage is that you can compile a program with CFLAGS="-O2 -g > -fPIE", and libtool's adding of -fPIC for shared libraries will work > reliably. If -fPIE can still override -fPIC, the result depends on > whether -fPIC comes before or after CFLAGS.
...which is exactly how all our other options work. The last one wins. Why should these be different? Using -fPIE in CFLAGS for libtool seems like a very specific use case, and I don't see it as sufficient justification for changing our ordinary option processing. Ian
