Re: [patch/rfa] Handle unwinding through export stubs on hpux

[Randolph Chung <randolph@tausq.org>]

> (Mark's already mentioned assignments inside conditionals).  Ok after 
> that is fixed.

here's the committed version. i also added some comments.

randolph


2004-05-17  Randolph Chung  <tausq@debian.org>

	* hppa-tdep.c (hppa_stub_frame_unwind_cache): For HPUX stub unwinding,
	check to see if we are unwinding an export stub.  Export stubs clobber
	the %rp in the call path and stores the original rp in a stack slot.

Index: hppa-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/hppa-tdep.c,v
retrieving revision 1.158
diff -u -p -r1.158 hppa-tdep.c
--- hppa-tdep.c	17 May 2004 15:16:39 -0000	1.158
+++ hppa-tdep.c	17 May 2004 16:44:16 -0000
@@ -1987,6 +1987,7 @@ hppa_stub_frame_unwind_cache (struct fra
 {
   struct gdbarch *gdbarch = get_frame_arch (next_frame);
   struct hppa_stub_unwind_cache *info;
+  struct unwind_table_entry *u;
 
   if (*this_cache)
     return *this_cache;
@@ -1995,8 +1996,26 @@ hppa_stub_frame_unwind_cache (struct fra
   *this_cache = info;
   info->saved_regs = trad_frame_alloc_saved_regs (next_frame);
 
-  info->saved_regs[HPPA_PCOQ_HEAD_REGNUM].realreg = HPPA_RP_REGNUM;
   info->base = frame_unwind_register_unsigned (next_frame, HPPA_SP_REGNUM);
+
+  if (gdbarch_osabi (gdbarch) == GDB_OSABI_HPUX_ELF 
+      || gdbarch_osabi (gdbarch) == GDB_OSABI_HPUX_SOM)
+    {
+      /* HPUX uses export stubs in function calls; the export stub clobbers
+         the return value of the caller, and, later restores it from the
+	 stack.  */
+      u = find_unwind_entry (frame_pc_unwind (next_frame));
+
+      if (u && u->stub_unwind.stub_type == EXPORT)
+	{
+          info->saved_regs[HPPA_PCOQ_HEAD_REGNUM].addr = info->base - 24;
+
+	  return info;
+	}
+    }
+
+  /* By default we assume that stubs do not change the rp.  */
+  info->saved_regs[HPPA_PCOQ_HEAD_REGNUM].realreg = HPPA_RP_REGNUM;
 
   return info;
 }