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-rw-r--r--gmon/mcount.c30
1 files changed, 28 insertions, 2 deletions
diff --git a/gmon/mcount.c b/gmon/mcount.c
index 523217d1d2..ac3584d4a5 100644
--- a/gmon/mcount.c
+++ b/gmon/mcount.c
@@ -48,14 +48,38 @@ static char sccsid[] = "@(#)mcount.c 8.1 (Berkeley) 6/4/93";
* _mcount updates data structures that represent traversals of the
* program's call graph edges. frompc and selfpc are the return
* address and function address that represents the given call graph edge.
- *
+ *
* Note: the original BSD code used the same variable (frompcindex) for
* both frompcindex and frompc. Any reasonable, modern compiler will
* perform this optimization.
*/
+#if 0
_MCOUNT_DECL(frompc, selfpc) /* _mcount; may be static, inline, etc */
register u_long frompc, selfpc;
+#endif
+
+/* GCC version 2 gives us a perfect magical function to get
+ just the information we need:
+ void *__builtin_return_address (unsigned int N)
+ returns the return address of the frame N frames up. */
+
+#if __GNUC__ < 2
+ #error "This file uses __builtin_return_address, a GCC 2 extension."
+#endif
+
+#include <sysdep.h>
+#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");
+#endif
+
+void
+_mcount (void)
{
+ register u_long selfpc = (u_long) __builtin_return_address (0);
+ register u_long frompc = (u_long) __builtin_return_address (1);
+
register u_short *frompcindex;
register struct tostruct *top, *prevtop;
register struct gmonparam *p;
@@ -154,7 +178,7 @@ _MCOUNT_DECL(frompc, selfpc) /* _mcount; may be static, inline, etc */
*frompcindex = toindex;
goto done;
}
-
+
}
done:
#ifdef KERNEL
@@ -171,8 +195,10 @@ overflow:
return;
}
+#if 0 /* Obsolete with __builtin_return_address. */
/*
* Actual definition of mcount function. Defined in <machine/profile.h>,
* which is included by <sys/gmon.h>.
*/
MCOUNT
+#endif