Re: [PATCH v2 1/2] tools lib traceevent: Export dynamic symbols used by traceevent plugins

[hekuang <hekuang@zoho.com>]

Hi, jirka

On 05/12/2015 08:37 PM, Jiri Olsa wrote:
> On Tue, May 12, 2015 at 06:41:56AM +0000, He Kuang wrote:
>
> SNIP
>
>>   	$(Q)$(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
>> @@ -373,7 +375,13 @@ $(LIB_FILE): $(LIBPERF_IN)
>>   LIBTRACEEVENT_FLAGS += plugin_dir=$(plugindir_SQ)
>>   
>>   $(LIBTRACEEVENT): FORCE
>> -	$(Q)$(MAKE) -C $(TRACE_EVENT_DIR) $(LIBTRACEEVENT_FLAGS) O=$(OUTPUT) $(OUTPUT)libtraceevent.a plugins
>> +	$(Q)$(MAKE) -C $(TRACE_EVENT_DIR) $(LIBTRACEEVENT_FLAGS) O=$(OUTPUT) $(OUTPUT)libtraceevent.a
>> +
>> +libtraceevent_plugins: FORCE
>> +	$(Q)$(MAKE) -C $(TRACE_EVENT_DIR) $(LIBTRACEEVENT_FLAGS) O=$(OUTPUT) plugins
>> +
>> +$(LIBTRACEEVENT_DYNAMIC_LIST): libtraceevent_plugins
>> +	$(Q)$(MAKE) -C $(TRACE_EVENT_DIR) $(LIBTRACEEVENT_FLAGS) O=$(OUTPUT) $(OUTPUT)libtraceevent-dynamic-list
> I thought the idea of v2 was not to introduce new target,
> something like in attached patch (not completely tested)
>
> jirka

There is a problem, the target perf executable is dependent on
the dynamic-list-file, so we should add plugins or the
dynamic-list-file to perf's dependencies.

As your patch below, the dynamic-list-file is built implictly
when building plugins, so we should not add it directly to the
dependency list of perf.

It seems new targets are needed. In the v2 patch,
dynamic-list-file is extracted out from plugins as perf's
dependncy.
>
> ---
> diff --git a/tools/lib/traceevent/Makefile b/tools/lib/traceevent/Makefile
> index d410da335e3d..57eed0403e6a 100644
> --- a/tools/lib/traceevent/Makefile
> +++ b/tools/lib/traceevent/Makefile
> @@ -23,6 +23,7 @@ endef
>   # Allow setting CC and AR, or setting CROSS_COMPILE as a prefix.
>   $(call allow-override,CC,$(CROSS_COMPILE)gcc)
>   $(call allow-override,AR,$(CROSS_COMPILE)ar)
> +$(call allow-override,NM,$(CROSS_COMPILE)nm)
>   
>   EXT = -std=gnu99
>   INSTALL = install
> @@ -169,7 +170,10 @@ $(OUTPUT)libtraceevent.so: $(TE_IN)
>   $(OUTPUT)libtraceevent.a: $(TE_IN)
>   	$(QUIET_LINK)$(RM) $@; $(AR) rcs $@ $^
>   
> -plugins: $(PLUGINS)
> +$(OUTPUT)libtraceevent-dynamic-list: $(PLUGINS)
> +	$(QUIET_GEN)$(call do_generate_dynamic_list_file, $(PLUGINS), $@)
> +
> +plugins: $(OUTPUT)libtraceevent-dynamic-list
>   
>   __plugin_obj = $(notdir $@)
>     plugin_obj = $(__plugin_obj:-in.o=)
> @@ -238,6 +242,13 @@ define do_install_plugins
>   	done
>   endef
>   
> +define do_generate_dynamic_list_file
> +	(echo '{';							\
> +	$(NM) -u -D $1 | awk 'NF>1 {print "\t"$$2";"}' | sort -u;	\
> +	echo '};';							\
> +	) > $2
> +endef
> +
>   install_lib: all_cmd install_plugins
>   	$(call QUIET_INSTALL, $(LIB_FILE)) \
>   		$(call do_install,$(LIB_FILE),$(bindir_SQ))
> diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
> index 03409cc02117..a8db98649ea3 100644
> --- a/tools/perf/Makefile.perf
> +++ b/tools/perf/Makefile.perf
> @@ -173,6 +173,8 @@ endif
>   LIBTRACEEVENT = $(TE_PATH)libtraceevent.a
>   export LIBTRACEEVENT
>   
> +LDFLAGS += -Xlinker --dynamic-list=$(TE_PATH)libtraceevent-dynamic-list
> +
>   LIBAPI = $(LIB_PATH)libapi.a
>   export LIBAPI
>   
> --
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