commit 520d437b9455560d099fe6bd9664be1f9f76868b Author: Siddhesh Poyarekar 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