arm: Use "nr" constraint for Systemtap probes [BZ #24164]

With the default "nor" constraint, current GCC will use the "o"
constraint for constants, after emitting the constant to memory.  That
results in unparseable Systemtap probe notes such as "-4@.L1052".
Removing the "o" alternative and using "nr" instead avoids this.

diff --git a/ChangeLog b/ChangeLog
index 17d53b1..ba5998c 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+2019-02-05  Florian Weimer  <fweimer@redhat.com>
+
+       [BZ #24164]
+       arm: Use "nr" constraint for Systemtap probes, to avoid the
+       compiler using memory operands for constants, due to the "o"
+       alternative in the default "nor" constraint.
+       * include/stap-probe.h [USE_STAP_PROBE]: Include
+       <stap-probe-machine.h>
+       * sysdeps/generic/stap-probe-machine.h: New file.
+       * sysdeps/arm/stap-probe-machine.h: Likewise.
+
 2019-02-04  Joseph Myers  <joseph@codesourcery.com>
 
        * malloc/malloc.c (tcache_get): Compare tcache->counts[tc_idx]

diff --git a/include/stap-probe.h b/include/stap-probe.h
index c53dd86..8c26292 100644 (file)
--- a/include/stap-probe.h
+++ b/include/stap-probe.h
@@ -21,6 +21,7 @@
 
 #ifdef USE_STAP_PROBE
 
+# include <stap-probe-machine.h>
 # include <sys/sdt.h>
 
 /* Our code uses one macro LIBC_PROBE (name, n, arg1, ..., argn).

diff --git a/sysdeps/arm/stap-probe-machine.h b/sysdeps/arm/stap-probe-machine.h
new file mode 100644 (file)
index 0000000..d27ca22
--- /dev/null
+++ b/sysdeps/arm/stap-probe-machine.h
@@ -0,0 +1,22 @@
+/* Macros for customizing Systemtap <sys/sdt.h>.  Arm version.
+   Copyright (C) 2019 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/>.  */
+
+/* The default "nor" constraint produces unparseable memory references
+   for constants.  Omit the problematic "o" constraint.  See bug 24164
+   and GCC PR 89146.  */
+#define STAP_SDT_ARG_CONSTRAINT nr

diff --git a/sysdeps/generic/stap-probe-machine.h b/sysdeps/generic/stap-probe-machine.h
new file mode 100644 (file)
index 0000000..2e5790c
--- /dev/null
+++ b/sysdeps/generic/stap-probe-machine.h
@@ -0,0 +1,19 @@
+/* Macros for customizing Systemtap <sys/sdt.h>.  Generic version.
+   Copyright (C) 2019 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/>.  */
+
+/* By default, there are no customizations.  */