How to build an executable with profiling?

[Steve Kargl]

On Wed, Jan 19, 2011 at 11:44:48AM +0100, Roman Divacky wrote:
> On Wed, Jan 19, 2011 at 11:18:22AM +0100, Hans Ottevanger wrote:
> > On 01/18/11 22:12, Roman Divacky wrote:
> > >On Tue, Jan 18, 2011 at 09:35:17AM -0800, Steve Kargl wrote:
> > >>On Tue, Jan 18, 2011 at 06:16:57PM +0100, Roman Divacky wrote:
> > >>>On Tue, Jan 18, 2011 at 04:43:13PM +0200, Kostik Belousov wrote:
> > >>>>On Tue, Jan 18, 2011 at 03:32:05PM +0100, Roman Divacky wrote:
> > >>>>>On Mon, Jan 17, 2011 at 10:44:11AM -0800, Steve Kargl wrote:
> > >>>>>>How does one build an executable for profiling with clang?
> > >>>>>
> > >>>>>LLVM (and thus clang) does not support GPROF profiling.
> > >>>>>
> > >>>>>>clang -o testf -O2 -march=native -pipe -static -pg 
> > >>>>>>-I/usr/local/include -I../mp testf.c -L/usr/local/lib -L../mp -lsgk 
> > >>>>>>-lmpfr -lgmp -L/usr/home/kargl/work/lib -lm_clang_p
> > >>>>>>clang: warning: the clang compiler does not support '-pg'
> > >>>>>>
> > 
> > If you are really desperate to find the hotspots in your program when 
> > compiled with clang, you could call clang with -v to find the call to 
> > /bin/ld. Then append _p to the appropriate libs if still needed and 
> > replace crt1.o by gcrt1.o while calling ld directly. E.g.
> > 
> > "/usr/bin/ld" -Bstatic -o testcoll /usr/lib/gcrt1.o /usr/lib/crti.o 
> > /usr/lib/crtbegin.o testcoll.o angle.o apsis.o error.o minmax.o qags.o 
> > qext.o qk21.o sort.o timint.o zero.o vmol.o -lm_p -lgcc -lgcc_eh -lc_p 
> > -lgcc -lgcc_eh -t /usr/lib/crtend.o /usr/lib/crtn.o
> > 
> > You will get a profile without the number of calls for the objects 
> > compiled with clang, but with the time spent. In my case:
> > 
> > granularity: each sample hit covers 4 byte(s) for 0.00% of 6.41 seconds
> > 
> >   %   cumulative   self              self     total
> >  time   seconds   seconds    calls  ms/call  ms/call  name
> >  30.3       1.94     1.94        0  100.00%           f_timint [2]
> >  20.2       3.24     1.29        0  100.00%           _mcount [3]
> >  19.4       4.48     1.24 21900000     0.00     0.00  exp [4]
> >  13.2       5.32     0.85        0   40.51%           vmol [1]
> >   7.3       5.79     0.47        0  100.00%           f_angle [5]
> >   2.8       5.98     0.18  1000000     0.00     0.00  pow [7]
> >   2.7       6.15     0.17        0   48.70%           qk21 [6]
> >   2.4       6.30     0.15        0  100.00%           .mcount (51)
> >   0.5       6.33     0.03        0  100.00%           zero [8]
> >   0.4       6.35     0.02        0  100.00%           qext [9]
> >   0.4       6.38     0.02        0  100.00%           qags [10]
> > ...
>  
> hm.. this is interesting. I wonder if it makes sense to teach the
> driver about this (it's a trivial change). opinions?
> 

I believe that this does not address the issue.  The issue is how
does one create libm_p.c and libc_p.c with clang.

-- 
Steve