On Wed, 20 Sep 2017, Steve Ellcey wrote: > On Wed, 2017-09-20 at 18:01 +0000, Joseph Myers wrote: > > > > (It may nevertheless be a good idea to set > > default_gnu_indirect_function=yes for AArch64 configurations in GCC > > that > > use glibc.) > > > > I have submitted a patch for that. > > https://gcc.gnu.org/ml/gcc-patches/2017-09/msg00285.html
I'm not entirely convinced the architecture conditions make sense there. The problem case is: binutils gains support for IFUNCs for an architecture that didn't previously have them. glibc detects the support, but cannot use IFUNC attributes with any existing GCC version for that architecture because GCC didn't know that binutils would gain that support. That means existing GCC versions unnecessarily cannot build glibc with new binutils for that architecture. (You could make the multi-arch support test check for IFUNC attribute support so multi-arch just gets disabled in that case, but it would be better to be able to build with existing GCC versions.) I.e. what I think would be better is: compiler support depends on the target OS, and make sure the linker gives a clear error (even better, that the assembler does so) if you try to build something with IFUNCs on an architecture without support. (If the linker / assembler don't already give such errors you could choose to keep architecture conditionals when building GCC with older binutils versions.) -- Joseph S. Myers jos...@codesourcery.com
