On Sat, Oct 30, 2010 at 8:13 AM, Roland Mainz <roland.ma...@nrubsig.org> wrote: > On Wed, Oct 13, 2010 at 9:05 PM, Brian Paul <bri...@vmware.com> wrote: >> On 10/13/2010 12:26 PM, Nicolas Kaiser wrote: >>> >>> This patch adds support for the compiler built-in Boolean type >>> to GLboolean and the "boolean" type in gallium >>> by bringing them in line with the "bool" type in stdbool.h. >>> >>> Signed-off-by: Nicolas Kaiser<ni...@nikai.net> >> >> Every GL/gl.h file I've seen over the years defines GLboolean as-is. >> It seems a bit risky (and unnecessary) to me to change it. > > Erm... using C99 |bool| from <stdbool.h> can lead to significant > performance improvements and code size reduction if there are lots of > bools/branches in your code because the compiler no longer has to > guess whether the variable may be used as boolean or not, it simply > can treat it as one even in low optimisation levels (and it helps in > cases when code spans more than one object file because not all > compilers do things like Sun's interprocedural optimiser (e.g. which > optimises and inlines across all source files in one step)).
The main problem we redefining something like GLboolean is it maybe an ABI change, the C99 bool AFAIK isn't == unsigned char, and it may affect the function signatures to starting using it in these places. Internally in mesa I'm less concerened. Dave. > This was the primary reason why Solaris got a <sys/stdbool.h> (e.g. > that kernel code can use C99 |bool| ; see OpenSolaris PSARC/2009/429, > http://mail.opensolaris.org/pipermail/opensolaris-arc/2009-August/017277.html > &co. for the discussion) and why we are working on doing this on other > larger pieces of code like AT&T AST codebase (which contains stuff > like libast and ksh93). > > ---- > > Bye, > Roland > > -- > __ . . __ > (o.\ \/ /.o) roland.ma...@nrubsig.org > \__\/\/__/ MPEG specialist, C&&JAVA&&Sun&&Unix programmer > /O /==\ O\ TEL +49 641 3992797 > (;O/ \/ \O;) > _______________________________________________ > mesa-dev mailing list > mesa-dev@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/mesa-dev > _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
