Commit 27e08bab authored by Stefan Hajnoczi's avatar Stefan Hajnoczi
Browse files

tracetool: work around ust <sys/sdt.h> include conflict 



Both the dtrace and ust backends may include <sys/sdt.h> but LTTng
Userspace Tracer 2.11 and later requires SDT_USE_VARIADIC to be defined
before including the header file.

This is a classic problem with C header files included from different
parts of a program. If the same header is included twice within the same
compilation unit then the first inclusion determines the macro
environment.

Work around this by defining SDT_USE_VARIADIC in the dtrace backend too.
It doesn't hurt and fixes a missing STAP_PROBEV() compiler error when
the ust backend is enabled together with the dtrace backend.

Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Message-id: 20200625140757.237012-1-stefanha@redhat.com
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
parent 7623b5ba

scripts/tracetool/backend/dtrace.py

+6 −0
Original line number Diff line number Diff line
@@ -40,6 +40,12 @@ def generate_h_begin(events, group): 
    else:

        header = "trace-dtrace.h"



    # Workaround for ust backend, which also includes <sys/sdt.h> and may

    # require SDT_USE_VARIADIC to be defined. If dtrace includes <sys/sdt.h>

    # first without defining SDT_USE_VARIADIC then ust breaks because the

    # STAP_PROBEV() macro is not defined.

    out('#define SDT_USE_VARIADIC 1')



    out('#include "%s"' % header,

        '')