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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