Re: [PATCH 1/2] tools lib traceevent: Export dynamic symbols used by traceevent plugins

[Arnaldo Carvalho de Melo <acme@kernel.org>]

Em Mon, May 11, 2015 at 04:33:09PM +0200, Jiri Olsa escreveu:
> On Mon, May 11, 2015 at 09:35:26AM +0000, He Kuang wrote:
> > Traceevent plugins need dynamic symbols exported from libtraceevent.a,
> > otherwise a dlopen error will occur during plugins loading.
> > 
> > This patch uses dynamic-list-file to export dynamic symbols which will
> > be used in plugins to perf executable.
> > 
> > The problem is covered up if feature-libpython is enabled, because
> > PYTHON_EMBED_LDOPTS contains '-Xlinker --export-dynamic' which adds all
> > symbols to the dynamic symbol table. So we should reproduce the problem
> > by setting NO_LIBPYTHON=1.
> 
> there's was another patch taking the shortcut:
>   http://marc.info/?l=linux-kernel&m=142885447432384&w=2
> 
> it seems it's not merged yet, but I like this one better

Ok, please let me know when something that can be merged is ready,

- Arnaldo
 
> SNIP
> 
> 
> > diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
> > index 03409cc..19c61e0 100644
> > --- a/tools/perf/Makefile.perf
> > +++ b/tools/perf/Makefile.perf
> > @@ -172,6 +172,7 @@ endif
> >  
> >  LIBTRACEEVENT = $(TE_PATH)libtraceevent.a
> >  export LIBTRACEEVENT
> > +LIBTRACEEVENT_DYNAMIC_LIST = $(TE_PATH)libtraceevent-dynamic-list
> >  
> >  LIBAPI = $(LIB_PATH)libapi.a
> >  export LIBAPI
> > @@ -278,8 +279,9 @@ build := -f $(srctree)/tools/build/Makefile.build dir=. obj
> >  $(PERF_IN): $(OUTPUT)PERF-VERSION-FILE $(OUTPUT)common-cmds.h FORCE
> >  	$(Q)$(MAKE) $(build)=perf
> >  
> > -$(OUTPUT)perf: $(PERFLIBS) $(PERF_IN)
> > -	$(QUIET_LINK)$(CC) $(CFLAGS) $(LDFLAGS) $(PERF_IN) $(LIBS) -o $@
> > +LD_LIBTRACEEVENT_FLAGS += -Xlinker --dynamic-list=$(LIBTRACEEVENT_DYNAMIC_LIST)
> > +$(OUTPUT)perf: $(PERFLIBS) $(PERF_IN) $(LIBTRACEEVENT_DYNAMIC_LIST)
> > +	$(QUIET_LINK)$(CC) $(CFLAGS) $(LDFLAGS) $(LD_LIBTRACEEVENT_FLAGS) $(PERF_IN) $(LIBS) -o $@
> >  
> >  $(GTK_IN): FORCE
> >  	$(Q)$(MAKE) $(build)=gtk
> > @@ -375,6 +377,9 @@ LIBTRACEEVENT_FLAGS += plugin_dir=$(plugindir_SQ)
> >  $(LIBTRACEEVENT): FORCE
> >  	$(Q)$(MAKE) -C $(TRACE_EVENT_DIR) $(LIBTRACEEVENT_FLAGS) O=$(OUTPUT) $(OUTPUT)libtraceevent.a plugins
> >  
> > +$(LIBTRACEEVENT_DYNAMIC_LIST): $(LIBTRACEEVENT)
> > +	$(Q)$(MAKE) -C $(TRACE_EVENT_DIR) $(LIBTRACEEVENT_FLAGS) O=$(OUTPUT) $(OUTPUT)libtraceevent-dynamic-list
> 
> hum, do we need extra target in Makefile.perf, it could be rebuilt any time
> 'plugins:' target in lib/tracevent/Makefile is called
> 
> jirka