[patch/rfa] Some fixes for hppa fallback unwinder

[Randolph Chung <randolph@tausq.org>]

This fixes some failures from signull.exp and more properly handles
stack adjustments when this unwinder is being used. It allows us to do
unwinding much better from assembly code.

i'll submit a separate patch to enable the gdb.asm tests for hppa.

ok to checkin?

randolph

2004-05-21  Randolph Chung  <tausq@debian.org>

	* hppa-tdep.c (hppa_fallback_frame_cache): Handle stack adjustment,
	unwinding from pc == 0, and multiple stack unwinds.

Index: hppa-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/hppa-tdep.c,v
retrieving revision 1.161
diff -u -p -r1.161 hppa-tdep.c
--- hppa-tdep.c	19 May 2004 02:38:28 -0000	1.161
+++ hppa-tdep.c	22 May 2004 05:22:22 -0000
@@ -1892,6 +1921,7 @@ static struct hppa_frame_cache *
 hppa_fallback_frame_cache (struct frame_info *next_frame, void **this_cache)
 {
   struct hppa_frame_cache *cache;
+  unsigned int frame_size;
   CORE_ADDR pc, start_pc, end_pc, cur_pc;
 
   cache = FRAME_OBSTACK_ZALLOC (struct hppa_frame_cache);
@@ -1900,40 +1930,41 @@ hppa_fallback_frame_cache (struct frame_
 
   pc = frame_func_unwind (next_frame);
   cur_pc = frame_pc_unwind (next_frame);
+  frame_size = 0;
 
-  find_pc_partial_function (pc, NULL, &start_pc, &end_pc);
-
-  if (start_pc == 0 || end_pc == 0)
+  if (pc != 0)
     {
-      error ("Cannot find bounds of current function (@0x%s), unwinding will "
+      find_pc_partial_function (pc, NULL, &start_pc, &end_pc);
+
+      if (start_pc == 0 || end_pc == 0)
+        {
+          error ("Cannot find bounds of current function (@0x%s), unwinding will "
 	     "fail.", paddr_nz (pc));
-      return cache;
-    }
+          return cache;
+        }
 
-  if (end_pc > cur_pc)
-    end_pc = cur_pc;
+      if (end_pc > cur_pc)
+        end_pc = cur_pc;
 
-  for (pc = start_pc; pc < end_pc; pc += 4)
-    {
-      unsigned int insn;
+      for (pc = start_pc; pc < end_pc; pc += 4)
+        {
+          unsigned int insn;
 
-      insn = read_memory_unsigned_integer (pc, 4);
+          insn = read_memory_unsigned_integer (pc, 4);
 
-      /* There are limited ways to store the return pointer into the
-	 stack.  */
-      if (insn == 0x6bc23fd9) /* stw rp,-0x14(sr0,sp) */
-	{
-	  cache->saved_regs[HPPA_RP_REGNUM].addr = -20;
-	  break;
-	}
-      else if (insn == 0x0fc212c1) /* std rp,-0x10(sr0,sp) */
-	{
-	  cache->saved_regs[HPPA_RP_REGNUM].addr = -16;
-	  break;
-	}
+	  frame_size += prologue_inst_adjust_sp (insn);
+
+          /* There are limited ways to store the return pointer into the
+	     stack.  */
+          if (insn == 0x6bc23fd9) /* stw rp,-0x14(sr0,sp) */
+	    cache->saved_regs[HPPA_RP_REGNUM].addr = -20;
+          else if (insn == 0x0fc212c1) /* std rp,-0x10(sr0,sp) */
+	    cache->saved_regs[HPPA_RP_REGNUM].addr = -16;
+        }
     }
 
-  cache->base = frame_unwind_register_unsigned (next_frame, HPPA_SP_REGNUM);
+  cache->base = frame_unwind_register_unsigned (next_frame, HPPA_SP_REGNUM) - frame_size;
+  trad_frame_set_value (cache->saved_regs, HPPA_SP_REGNUM, cache->base);
 
   if (trad_frame_addr_p (cache->saved_regs, HPPA_RP_REGNUM))
     {
-- 
Randolph Chung
Debian GNU/Linux Developer, hppa/ia64 ports
http://www.tausq.org/