From edf49cd0a3eb52f8a737f82763df9de022a29042 Mon Sep 17 00:00:00 2001
From: mmitchel <mmitchel@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Sat, 19 May 2001 17:55:49 +0000
Subject: [PATCH] 	* defaults.h
 (TARGET_ALLOWS_PROFILING_WITHOUT_FRAME_POINTER): New 	macro. 	* tm.texi
 (TARGET_ALLOWS_PROFILING_WITHOUT_FRAME_POINTER): 	Document it. 	*
 toplev.c (main): If the target does not allow profiling without 	a
 frame pointer, issue an error message. 	* config/i386/linux.h
 (TARGET_ALLOWS_PROFILING_WITHOUT_FRAME_POINTER): 	Define it to false.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/branches/gcc-3_0-branch@42311 138bc75d-0d04-0410-961f-82ee72b054a4
---
 gcc/ChangeLog           | 11 +++++++++++
 gcc/config/i386/linux.h |  9 +++++++++
 gcc/defaults.h          |  7 +++++++
 gcc/tm.texi             | 15 +++++++++++++++
 gcc/toplev.c            | 10 ++++++++++
 5 files changed, 52 insertions(+)

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 63bb4582276..04ee3cac8e7 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,14 @@
+2001-05-19  Mark Mitchell  <mark@codesourcery.com>
+
+	* defaults.h (TARGET_ALLOWS_PROFILING_WITHOUT_FRAME_POINTER): New
+	macro.
+	* tm.texi (TARGET_ALLOWS_PROFILING_WITHOUT_FRAME_POINTER):
+	Document it.
+	* toplev.c (main): If the target does not allow profiling without
+	a frame pointer, issue an error message.
+	* config/i386/linux.h (TARGET_ALLOWS_PROFILING_WITHOUT_FRAME_POINTER): 
+	Define it to false.
+	
 Sat May 19 09:40:45 2001  Denis Chertykov  <denisc@overta.ru>
 
 	* regrename.c (regrename_optimize): frame pointer register can
diff --git a/gcc/config/i386/linux.h b/gcc/config/i386/linux.h
index 8f9545c2c71..09cf70ca732 100644
--- a/gcc/config/i386/linux.h
+++ b/gcc/config/i386/linux.h
@@ -72,6 +72,15 @@ Boston, MA 02111-1307, USA.  */
     fprintf (FILE, "\tcall\tmcount\n");					\
 }
 
+/* True if it is possible to profile code that does not have a frame
+   pointer.  
+
+   The GLIBC version of mcount for the x86 assumes that there is a
+   frame, so we cannot allow profiling without a frame pointer.  */
+
+#undef TARGET_ALLOWS_PROFILING_WITHOUT_FRAME_POINTER
+#define TARGET_ALLOWS_PROFILING_WITHOUT_FRAME_POINTER false
+
 #undef SIZE_TYPE
 #define SIZE_TYPE "unsigned int"
  
diff --git a/gcc/defaults.h b/gcc/defaults.h
index 58b77409236..22cd3830809 100644
--- a/gcc/defaults.h
+++ b/gcc/defaults.h
@@ -319,5 +319,12 @@ do {								\
 #define ASM_PREFERRED_EH_DATA_FORMAT(CODE,GLOBAL)  DW_EH_PE_absptr
 #endif
 
+/* True if it is possible to profile code that does not have a frame
+   pointer.  */
+
+#ifndef TARGET_ALLOWS_PROFILING_WITHOUT_FRAME_POINTER
+#define TARGET_ALLOWS_PROFILING_WITHOUT_FRAME_POINTER true
+#endif
+
 #endif  /* GCC_DEFAULTS_H */
 
diff --git a/gcc/tm.texi b/gcc/tm.texi
index 8a9f0170531..caefab51b70 100644
--- a/gcc/tm.texi
+++ b/gcc/tm.texi
@@ -3998,6 +3998,21 @@ Registers or condition codes clobbered by @code{FUNCTION_PROLOGUE} or
 @item BLOCK_PROFILER_CODE
 A C function or functions which are needed in the library to
 support block profiling.
+
+@findex TARGET_ALLOWS_PROFILING_WITHOUT_FRAME_POINTER
+@item TARGET_ALLOWS_PROFILING_WITHOUT_FRAME_POINTER
+On some targets, it is impossible to use profiling when the frame
+pointer has been omitted.  For example, on x86 GNU/Linux systems, 
+the @code{mcount} routine provided by the GNU C Library finds the
+address of the routine that called the routine that called @code{mcount} 
+by looking in the immediate caller's stack frame.  If the immediate
+caller has no frame pointer, this lookup will fail.
+
+By default, GCC assumes that the target does allow profiling when the
+frame pointer is omitted.  This macro should be defined to a C
+expression that evaluates to @code{false} if the target does not allow
+profiling when the frame pointer is omitted.
+
 @end table
 
 @node Inlining
diff --git a/gcc/toplev.c b/gcc/toplev.c
index ddde8ef6613..e825a30d704 100644
--- a/gcc/toplev.c
+++ b/gcc/toplev.c
@@ -4907,6 +4907,16 @@ main (argc, argv)
     warning ("this target machine does not have delayed branches");
 #endif
 
+  /* Some operating systems do not allow profiling without a frame
+     pointer.  */
+  if (!TARGET_ALLOWS_PROFILING_WITHOUT_FRAME_POINTER
+      && profile_flag
+      && flag_omit_frame_pointer)
+    {
+      error ("profiling does not work without a frame pointer");
+      flag_omit_frame_pointer = 0;
+    }
+    
   user_label_prefix = USER_LABEL_PREFIX;
   if (flag_leading_underscore != -1)
     {
-- 
2.11.4.GIT