Re: [PATCH] perf data: Fix babeltrace detection

[Jiri Olsa]

On Tue, Oct 08, 2019 at 07:21:44AM -0700, Andi Kleen wrote:
> On Tue, Oct 08, 2019 at 01:52:40PM +0200, Jiri Olsa wrote:
> > On Mon, Oct 07, 2019 at 10:41:20AM -0700, Andi Kleen wrote:
> > > From: Andi Kleen <ak@xxxxxxxxxxxxxxx>
> > > 
> > > The symbol the feature file checks for is now actually in -lbabeltrace,
> > > not -lbabeltrace-ctf, at least as of libbabeltrace-1.5.6-2.fc30.x86_64
> > > 
> > > Always add both libraries to fix the feature detection.
> > 
> > well, we link with libbabeltrace-ctf.so which links with libbabeltrace.so
> > 
> > I guess we can link it as well, but where do you see it fail?
> 
> On FC30 the .so file is just a symlink, so it doesn't pull
> in the other library.
> 
> $ gcc test-libbabeltrace.c -lbabeltrace-ctf
> /usr/bin/ld:
> /usr/lib/gcc/x86_64-redhat-linux/9/../../../../lib64/libbabeltrace-ctf.so:
> undefined reference to `bt_packet_seek_get_error'
> /usr/bin/ld:
> /usr/lib/gcc/x86_64-redhat-linux/9/../../../../lib64/libbabeltrace-ctf.so:
> undefined reference to `bt_packet_seek_set_error'
> collect2: error: ld returned 1 exit status

I'm confused,
the test-libbabeltrace.c checks for bt_ctf_stream_class_get_packet_context_type
which is in libbabeltrace-ctf:

	[jolsa@dell-r440-01 feature]$ nm -D /usr/lib64/libbabeltrace-ctf.so | grep bt_ctf_stream_class_get_packet_context_type
	0000000000032960 T bt_ctf_stream_class_get_packet_context_type
	[jolsa@dell-r440-01 feature]$ cat /etc/redhat-release 
	Fedora release 30 (Thirty)
	[jolsa@dell-r440-01 feature]$ rpm -qa | grep  libbabeltrace-1.5.6-2.fc30.x86_64
	libbabeltrace-1.5.6-2.fc30.x86_64

I also get proper feature detection on F30:

	$ make VF=1
	...                 libbabeltrace: [ on  ]


jirka

> 
> $ ls -l /usr/lib64/libbabeltrace-ctf.so
> lrwxrwxrwx 1 root root 26 Jan 31  2019 /usr/lib64/libbabeltrace-ctf.so
> -> libbabeltrace-ctf.so.1.0.0
> 
> $ rpm -qf /usr/lib64/libbabeltrace-ctf.so
> libbabeltrace-devel-1.5.6-2.fc30.x86_64
> 
> -Andi