1/* Macros for defining Systemtap <sys/sdt.h> static probe points.
 2   Copyright (C) 2012-2025 Free Software Foundation, Inc.
 3   This file is part of the GNU C Library.
 4
 5   The GNU C Library is free software; you can redistribute it and/or
 6   modify it under the terms of the GNU Lesser General Public
 7   License as published by the Free Software Foundation; either
 8   version 2.1 of the License, or (at your option) any later version.
 9
10   The GNU C Library is distributed in the hope that it will be useful,
11   but WITHOUT ANY WARRANTY; without even the implied warranty of
12   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13   Lesser General Public License for more details.
14
15   You should have received a copy of the GNU Lesser General Public
16   License along with the GNU C Library; if not, see
17   <https://www.gnu.org/licenses/>.  */
18
19#ifndef _STAP_PROBE_H
20#define _STAP_PROBE_H 1
21
22#ifdef USE_STAP_PROBE
23
24# include <stap-probe-machine.h>
25# include <sys/sdt.h>
26
27/* Our code uses one macro LIBC_PROBE (name, n, arg1, ..., argn).
28
29   Without USE_STAP_PROBE, that does nothing but evaluates all
30   its arguments (to prevent bit rot, unlike e.g. assert).
31
32   Systemtap's header defines the macros STAP_PROBE (provider, name) and
33   STAP_PROBEn (provider, name, arg1, ..., argn).  For "provider" we paste
34   in MODULE_NAME (libc, libpthread, etc.) automagically.
35
36   The format of the arg parameters is discussed here:
37
38   https://sourceware.org/systemtap/wiki/UserSpaceProbeImplementation
39
40   The precise details of how register names are specified is
41   architecture specific and can be found in the gdb and SystemTap
42   source code.  */
43
44# define LIBC_PROBE(name, n, ...)	\
45  LIBC_PROBE_1 (MODULE_NAME, name, n, ## __VA_ARGS__)
46
47# define LIBC_PROBE_1(lib, name, n, ...) \
48  STAP_PROBE##n (lib, name, ## __VA_ARGS__)
49
50# define STAP_PROBE0		STAP_PROBE
51
52# define LIBC_PROBE_ASM(name, template) \
53  STAP_PROBE_ASM (MODULE_NAME, name, template)
54
55# define LIBC_PROBE_ASM_OPERANDS STAP_PROBE_ASM_OPERANDS
56
57#else  /* Not USE_STAP_PROBE.  */
58
59# ifndef __ASSEMBLER__
60/* Evaluate all the arguments and verify that N matches their number.  */
61#  define LIBC_PROBE(name, n, ...) STAP_PROBE##n (__VA_ARGS__)
62
63#  define STAP_PROBE0()				do {} while (0)
64#  define STAP_PROBE1(a1)			do {} while (0)
65#  define STAP_PROBE2(a1, a2)			do {} while (0)
66#  define STAP_PROBE3(a1, a2, a3)		do {} while (0)
67#  define STAP_PROBE4(a1, a2, a3, a4)		do {} while (0)
68
69# else
70#  define LIBC_PROBE(name, n, ...)		/* Nothing.  */
71# endif
72
73# define LIBC_PROBE_ASM(name, template)		/* Nothing.  */
74# define LIBC_PROBE_ASM_OPERANDS(n, ...)	/* Nothing.  */
75
76#endif	/* USE_STAP_PROBE.  */
77
78#endif	/* stap-probe.h */