This is the mail archive of the libc-alpha@sourceware.org mailing list for the glibc project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: [PATCHv3] powerpc: ABI change - add HWCAP/HWCAP2/platform info to TCB


On Wed, 23 Sep 2015, Peter Bergner wrote:

> The idea is that applications will use the builtins supplied by GCC
> (and other compilers) and will not access this info directly.
> In GCC, my plan is to first add a configure test looking for the
> symbol and if it doesn't exist, then I'll make the builtins return

(Please make that configure test respect --with-glibc-version so that the 
results can be correct when a bootstrap compiler is configured without 
pre-existing glibc.)

> false for all queries.  If it does exist during configure, I'll emit
> code to load/test the TCB entries, but I'll also emit a data reference
> to the symbol which will cause a linker/loader error in the event the
> user attempts to link/run against an old glibc.

In that case, the name should still be in the reserved namespace, and the 
entry in the Versions file should have a comment explaining this use by 
GCC builtins (all reserved-namespace entries in Versions files outside of 
GLIBC_PRIVATE should have comments explaining why they are needed).

-- 
Joseph S. Myers
joseph@codesourcery.com


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]