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. Paolo
