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

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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: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20200625140757.237012-1-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Stefan Hajnoczi 2020-06-25 15:07:57 +01:00
parent 7623b5ba01
commit 27e08bab94
1 changed files with 6 additions and 0 deletions
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6
scripts/tracetool/backend/dtrace.py
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@ -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,
'')