From 3a097cc7a18309c864186c1b864b90889d2a45e9 Mon Sep 17 00:00:00 2001
From: Roland McGrath <roland@hack.frob.com>
Date: Fri, 25 May 2012 13:40:20 -0700
Subject: Add --enable-systemtap configuration to define static probe points.

---
 include/stap-probe.h | 80 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 80 insertions(+)
 create mode 100644 include/stap-probe.h

(limited to 'include')

diff --git a/include/stap-probe.h b/include/stap-probe.h
new file mode 100644
index 0000000000..1051ad1980
--- /dev/null
+++ b/include/stap-probe.h
@@ -0,0 +1,80 @@
+/* Macros for defining Systemtap <sys/sdt.h> static probe points.
+   Copyright (C) 2012 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef _STAP_PROBE_H
+#define _STAP_PROBE_H 1
+
+#ifdef USE_STAP_PROBE
+
+# include <sys/sdt.h>
+
+/* Our code uses one macro LIBC_PROBE (name, n, arg1, ..., argn).
+
+   Without USE_STAP_PROBE, that does nothing but evaluates all
+   its arguments (to prevent bit rot, unlike e.g. assert).
+
+   Systemtap's header defines the macros STAP_PROBE (provider, name) and
+   STAP_PROBEn (provider, name, arg1, ..., argn).  For "provider" we paste
+   in the IN_LIB name (libc, libpthread, etc.) automagically.  */
+
+# ifndef NOT_IN_libc
+#  define IN_LIB	libc
+# elif !defined IN_LIB
+/* This is intentionally defined with extra unquoted commas in it so
+   that macro substitution will bomb out when it is used.  We don't
+   just use #error here, so that this header can be included by
+   other headers that use LIBC_PROBE inside their own macros.  We
+   only want such headers to fail to compile if those macros are
+   actually used in a context where IN_LIB has not been defined.  */
+#  define IN_LIB	,,,missing -DIN_LIB=... -- not extra-lib.mk?,,,
+# endif
+
+# define LIBC_PROBE(name, n, ...)	\
+  LIBC_PROBE_1 (IN_LIB, name, n, ## __VA_ARGS__)
+
+# define LIBC_PROBE_1(lib, name, n, ...) \
+  STAP_PROBE##n (lib, name, ## __VA_ARGS__)
+
+# define STAP_PROBE0		STAP_PROBE
+
+# define LIBC_PROBE_ASM(name, template) \
+  STAP_PROBE_ASM (IN_LIB, name, template)
+
+# define LIBC_PROBE_ASM_OPERANDS STAP_PROBE_ASM_OPERANDS
+
+#else  /* Not USE_STAP_PROBE.  */
+
+# 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)
+# else
+#  define LIBC_PROBE(name, n, ...)		/* Nothing.  */
+# endif
+
+# define LIBC_PROBE_ASM(name, template)		/* Nothing.  */
+# define LIBC_PROBE_ASM_OPERANDS(n, ...)	/* Nothing.  */
+
+#endif	/* USE_STAP_PROBE.  */
+
+#endif	/* stap-probe.h */
-- 
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