Messages in this thread | | | Subject | Re: [PATCH 1/2] tools lib traceevent: Export dynamic symbols used by traceevent plugins | From | He Kuang <> | Date | Tue, 12 May 2015 14:42:10 +0800 |
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Hi, jirka
On 2015/5/11 22:33, Jiri Olsa wrote: > 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 > > 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
Yes, the dynamic-list-file should be rebuilt when plugins changed, and not depends on $(LIBTRACEEVENT).
I sent a new version, please review that patch.
$ touch ../lib/traceevent/plugin_function.c $ make CC plugin_function.o LD plugin_function-in.o LINK plugin_function.so GEN libtraceevent-dynamic-list LINK perf
Thanks.
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