Re: [patches] Export new ARM mcount routine

["Joseph S. Myers" <joseph@xxxxxxxxxxxxxxxx>]

On Fri, 4 Apr 2008, Paul Brook wrote:

> The patch below exports the recently added __gnu_mcount_nc routine from 
> libc.so.  For backports to earlier branches we also need to add GLIBC_2.8 to 
> Versions.def
> 
> Ok?

I have committed this patch to trunk/2.7/2.6/2.5.

I have also committed this further fix to this code.

Daniel, I believe what follows this is the full cumulative patch suitable 
for FSF glibc ports, but I haven't tested it there.

Index: ports/sysdeps/arm/eabi/machine-gmon.h
===================================================================
--- ports/sysdeps/arm/eabi/machine-gmon.h	(revision 5881)
+++ ports/sysdeps/arm/eabi/machine-gmon.h	(working copy)
@@ -75,6 +75,7 @@
 {									\
   __asm__("push		{r0, r1, r2, r3, fp, lr};"			\
 	  "movs		r0, fp;"					\
+	  "ittt		ne;"						\
 	  "ldrne	r0, [r0, #-4];"					\
 	  "movsne	r1, lr;"					\
 	  "blne		mcount_internal;"				\
Index: ports/ChangeLog.eglibc
===================================================================
--- ports/ChangeLog.eglibc	(revision 5881)
+++ ports/ChangeLog.eglibc	(working copy)
@@ -1,5 +1,11 @@
 2008-04-11  Paul Brook  <paul@xxxxxxxxxxxxxxxx>
+	    Sandra Loosemore  <sandra@xxxxxxxxxxxxxxxx>
 
+	* sysdeps/arm/eabi/machine-gmon.h (_mcount):  Make the thumb2
+	version compile without error.
+
+2008-04-11  Paul Brook  <paul@xxxxxxxxxxxxxxxx>
+
 	* sysdeps/arm/eabi/Versions: Add __gnu_mcount_nc.
 
 2008-04-02  Paul Brook  <paul@xxxxxxxxxxxxxxxx>




Cumulative patch:

2008-04-11  Paul Brook  <paul@xxxxxxxxxxxxxxxx>
	    Sandra Loosemore  <sandra@xxxxxxxxxxxxxxxx>

	* sysdeps/arm/eabi/machine-gmon.h: New file.
	* sysdeps/arm/eabi/Versions: Add __gnu_mcount_nc.

Index: sysdeps/arm/eabi/machine-gmon.h
===================================================================
--- sysdeps/arm/eabi/machine-gmon.h	(revision 0)
+++ sysdeps/arm/eabi/machine-gmon.h	(revision 5885)
@@ -0,0 +1,99 @@
+/* Machine-dependent definitions for profiling support.  ARM EABI version.
+   Copyright (C) 2008 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, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+/* GCC for the ARM cannot compile __builtin_return_address(N) for N != 0, 
+   so we must use an assembly stub.  */
+
+#include <sysdep.h>
+static void mcount_internal (u_long frompc, u_long selfpc) __attribute_used__;
+
+#define _MCOUNT_DECL(frompc, selfpc) \
+static void mcount_internal (u_long frompc, u_long selfpc)
+
+/* Use an assembly stub with a special ABI.  The calling lr has been
+   pushed to the stack (which will be misaligned).  We should preserve
+   all registers except ip and pop a word off the stack.
+
+   NOTE: This assumes mcount_internal does not clobber any non-core
+   (coprocessor) registers.  Currently this is true, but may require
+   additional attention in the future.
+
+   The calling sequence looks something like:
+func:
+   push {lr}
+   bl __gnu_mount_nc
+   <function body>
+ */
+
+
+#define MCOUNT								\
+void __attribute__((__naked__)) __gnu_mcount_nc(void)			\
+{									\
+    asm ("push {r0, r1, r2, r3, lr}\n\t"				\
+	 "bic r1, lr, #1\n\t"						\
+	 "ldr r0, [sp, #20]\n\t"					\
+	 "bl mcount_internal\n\t"					\
+	 "pop {r0, r1, r2, r3, ip, lr}\n\t"				\
+	 "bx ip");							\
+}									\
+OLD_MCOUNT
+
+/* Provide old mcount for backwards compatibility.  This requires
+   code be compiled with APCS frame pointers.  */
+
+#ifndef NO_UNDERSCORES
+/* The asm symbols for C functions are `_function'.
+   The canonical name for the counter function is `mcount', no _.  */
+void _mcount (void) asm ("mcount");
+#else
+/* The canonical name for the function is `_mcount' in both C and asm,
+   but some old asm code might assume it's `mcount'.  */
+void _mcount (void);
+weak_alias (_mcount, mcount)
+#endif
+
+#ifdef __thumb2__
+
+#define OLD_MCOUNT							\
+void __attribute__((__naked__)) _mcount (void)				\
+{									\
+  __asm__("push		{r0, r1, r2, r3, fp, lr};"			\
+	  "movs		r0, fp;"					\
+	  "ittt		ne;"						\
+	  "ldrne	r0, [r0, #-4];"					\
+	  "movsne	r1, lr;"					\
+	  "blne		mcount_internal;"				\
+	  "pop		{r0, r1, r2, r3, fp, pc}");			\
+}
+
+#else
+
+#define OLD_MCOUNT							\
+void __attribute__((__naked__)) _mcount (void)				\
+{									\
+  __asm__("stmdb	sp!, {r0, r1, r2, r3, fp, lr};"			\
+	  "movs		fp, fp;"					\
+	  "ldrne	r0, [fp, #-4];"					\
+	  "movnes	r1, lr;"					\
+	  "blne		mcount_internal;"				\
+	  "ldmia	sp!, {r0, r1, r2, r3, fp, lr};"			\
+	  "bx		lr");						\
+}
+
+#endif
Index: sysdeps/arm/eabi/Versions
===================================================================
--- sysdeps/arm/eabi/Versions	(revision 5760)
+++ sysdeps/arm/eabi/Versions	(revision 5885)
@@ -14,4 +14,7 @@
     # Helper routines
     __gnu_Unwind_Find_exidx;
   }
+  GLIBC_2.8 {
+    __gnu_mcount_nc;
+  }
 }


-- 
Joseph S. Myers
joseph@xxxxxxxxxxxxxxxx