commit 520d437b9455560d099fe6bd9664be1f9f76868b
Author: Siddhesh Poyarekar <siddhesh@redhat.com>
Date: Tue Dec 3 12:26:12 2013 +0530
[BZ #16195] Fix build warnings from systemtap probes in non-systemtap configurations
Joseph pointed out in the bug report (and in an earlier thread) that
systemtap probes cause build time warnings like the following:
../sysdeps/ieee754/dbl-64/e_atan2.c:602:4: warning: the address of
'p' will always evaluate as 'true' [-Waddress]
due to the fact that we're now passing non-weak variables to
LIBC_PROBE in the libm probes. This happens only on configurations
that do not enable systemtap. The macro definition of LIBC_PROBE in
this case only acts as a sanity checker to ensure that the number
parameters passed to LIBC_PROBE is equal to the argument count
parameter passed before it. This can be done in a much simpler manner
by just adding a macro definition for each number of arguments. I am
assuming here that we don't really want to bother with supporting
LIBC_PROBE with an indeterminate number of arguments and if there is a
need for a probe to have more data than what is currently supported (4
arguments), one could simply add an additional macro here.
diff --git a/include/stap-probe.h b/include/stap-probe.h
index 0f65c29b2b5c5dde..0ddb5d5fc9f740dd 100644
--- a/include/stap-probe.h
+++ b/include/stap-probe.h
@@ -49,13 +49,14 @@
# ifndef __ASSEMBLER__
/* Evaluate all the arguments and verify that N matches their number. */
-# define LIBC_PROBE(name, n, ...) \
- do { \
- _Bool __libc_probe_args[] = { 0, ## __VA_ARGS__ }; \
- _Bool __libc_probe_verify_n[(sizeof __libc_probe_args / sizeof (_Bool)) \
- == n + 1 ? 1 : -1]; \
- (void) __libc_probe_verify_n; \
- } while (0)
+#define LIBC_PROBE(name, n, ...) STAP_PROBE##n (__VA_ARGS__)
+
+#define STAP_PROBE0()
+#define STAP_PROBE1(a1)
+#define STAP_PROBE2(a1, a2)
+#define STAP_PROBE3(a1, a2, a3)
+#define STAP_PROBE4(a1, a2, a3, a4)
+
# else
# define LIBC_PROBE(name, n, ...) /* Nothing. */
# endif