[patch/hppa/rfa] unwind fix for functions with no debug info

[Randolph Chung <randolph@tausq.org>]

The attached patch fixes a problem reported by Dave Anglin and others.
When compiled without debug information, static functions have no symbol
table entry in gdb. In this case, frame_func_unwind returns the starting
address of the previously visible function. Using that to do unwinding
causes all sorts of brokeness.... 

On hppa, each properly defined function has an unwind record which gives
the starting and ending address of the function. We can use that to
do unwinding more properly.

Tested on hppa-linux with no regressions.

Ok to apply?

randolph

2004-11-03  Randolph Chung  <tausq@debian.org>

	* hppa-tdep.c (hppa_frame_cache): Avoid using frame_func_unwind () to
	locate the beginning of the function.  When objects are compiled without
	debug symbols, frame_func_unwind can return the wrong function.  We
	can do better than that by using unwind records.
	(hppa_frame_this_id): Likewise.


Index: hppa-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/hppa-tdep.c,v
retrieving revision 1.175
diff -u -p -r1.175 hppa-tdep.c
--- hppa-tdep.c	31 Oct 2004 21:09:28 -0000	1.175
+++ hppa-tdep.c	3 Nov 2004 16:18:40 -0000
@@ -1580,7 +1580,7 @@ hppa_frame_cache (struct frame_info *nex
   cache->saved_regs = trad_frame_alloc_saved_regs (next_frame);
 
   /* Yow! */
-  u = find_unwind_entry (frame_func_unwind (next_frame));
+  u = find_unwind_entry (frame_pc_unwind (next_frame));
   if (!u)
     {
       if (hppa_debug)
@@ -1630,7 +1630,7 @@ hppa_frame_cache (struct frame_info *nex
        symbol information.  hppa_skip_prologue also bounds the returned
        pc by the passed in pc, so it will not return a pc in the next
        function.  */
-    prologue_end = hppa_skip_prologue (frame_func_unwind (next_frame));
+    prologue_end = hppa_skip_prologue (u->region_start);
     end_pc = frame_pc_unwind (next_frame);
 
     if (prologue_end != 0 && end_pc > prologue_end)
@@ -1638,7 +1638,7 @@ hppa_frame_cache (struct frame_info *nex
 
     frame_size = 0;
 
-    for (pc = frame_func_unwind (next_frame);
+    for (pc = u->region_start;
 	 ((saved_gr_mask || saved_fr_mask
 	   || looking_for_sp || looking_for_rp
 	   || frame_size < (u->Total_frame_size << 3))
@@ -1881,8 +1881,14 @@ static void
 hppa_frame_this_id (struct frame_info *next_frame, void **this_cache,
 			   struct frame_id *this_id)
 {
-  struct hppa_frame_cache *info = hppa_frame_cache (next_frame, this_cache);
-  (*this_id) = frame_id_build (info->base, frame_func_unwind (next_frame));
+  struct hppa_frame_cache *info;
+  CORE_ADDR pc = frame_pc_unwind (next_frame);
+  struct unwind_table_entry *u;
+
+  info = hppa_frame_cache (next_frame, this_cache);
+  u = find_unwind_entry (pc);
+
+  (*this_id) = frame_id_build (info->base, u->region_start);
 }
 
 static void
-- 
Randolph Chung
Debian GNU/Linux Developer, hppa/ia64 ports
http://www.tausq.org/