[PATCH]: Fix suboptimal mcount on sparc.

[David Miller <davem at davemloft dot net>]

The current use of the generic version results in a full stack frame
being created for _mcount, and also a flush of the entire set of
register windows just to grab the parent program counter.

This patch fixes all of those inefficiencies.

Fully regression tested on sparc*-linux and sparc64*-linux

Please apply, thanks.

2008-05-14  David S. Miller  <davem@davemloft.net>

	* sysdeps/sparc/machine-gmon.h: New file.
	* sysdeps/sparc/sparc-mcount.S: Likewise.
	* sysdeps/sparc/Makefile: Add sparc-mcount target to
	sysdep_routines in gmon directory.
---
 sysdeps/sparc/Makefile       |    4 ++++
 sysdeps/sparc/machine-gmon.h |   33 +++++++++++++++++++++++++++++++++
 sysdeps/sparc/sparc-mcount.S |   29 +++++++++++++++++++++++++++++
 3 files changed, 66 insertions(+), 0 deletions(-)
 create mode 100644 sysdeps/sparc/machine-gmon.h
 create mode 100644 sysdeps/sparc/sparc-mcount.S

diff --git a/sysdeps/sparc/Makefile b/sysdeps/sparc/Makefile
index 40323a0..9fa5324 100644
--- a/sysdeps/sparc/Makefile
+++ b/sysdeps/sparc/Makefile
@@ -1,6 +1,10 @@
 # The Sparc `long double' is a distinct type we support.
 long-double-fcts = yes
 
+ifeq ($(subdir),gmon)
+sysdep_routines += sparc-mcount
+endif
+
 ifeq ($(subdir),db2)
 CPPFLAGS += -DHAVE_SPINLOCKS=1 -DHAVE_ASSEM_SPARC_GCC=1
 endif
diff --git a/sysdeps/sparc/machine-gmon.h b/sysdeps/sparc/machine-gmon.h
new file mode 100644
index 0000000..296c5ff
--- /dev/null
+++ b/sysdeps/sparc/machine-gmon.h
@@ -0,0 +1,33 @@
+/* sparc-specific implementation of profiling support.
+   Copyright (C) 2008 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by David S. Miller <davem@davemloft.net>, 2008
+
+   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, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <sysdep.h>
+
+/* We must not pollute the global namespace.  */
+#define mcount_internal __mcount_internal
+
+extern void mcount_internal (u_long frompc, u_long selfpc) internal_function;
+
+#define _MCOUNT_DECL(frompc, selfpc) \
+void internal_function mcount_internal (u_long frompc, u_long selfpc)
+
+/* Define MCOUNT as empty since we have the implementation in another
+   file.  */
+#define MCOUNT
diff --git a/sysdeps/sparc/sparc-mcount.S b/sysdeps/sparc/sparc-mcount.S
new file mode 100644
index 0000000..573b08f
--- /dev/null
+++ b/sysdeps/sparc/sparc-mcount.S
@@ -0,0 +1,29 @@
+/* sparc-specific implemetation of profiling support.
+   Copyright (C) 2008 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by David S. Miller <davem@davemloft.net>, 2008.
+
+   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, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <sysdep.h>
+
+ENTRY(_mcount)
+	mov	%i7, %o0
+	ba	__mcount_internal
+	 mov	%o7, %o1
+END(_mcount)
+
+weak_alias (_mcount, mcount)
-- 
1.5.5.1.57.g5909c