RFA/ARM: Switch mode when setting PC

[Daniel Jacobowitz <drow@mvista.com>]

This patch fixes several failures in virtfunc.exp for arm-sim/-mthumb.  The
problem is that the non-virtual thunk for pDe->vg() is emitted in ARM mode
and called via _call_via_r2.  But the rest of the program is Thumb mode, and
nothing tells the simulator (or target; I haven't tested this on hardware
yet but I expect the same result) to switch to ARM.  So it gets very
confused.

This is somewhat suboptimal in that if you want, for some reason, to call
something marked as an ARM function with Thumb mode enabled you will have to
set $ps yourself _after_ setting $pc.  I think it's still a good idea,
though.  OK?

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer

2004-01-15  Daniel Jacobowitz  <drow@mvista.com>

	* arm-tdep.c (arm_write_pc): New function.
	(arm_gdbarch_init): Call set_gdbarch_write_pc.

Index: arm-tdep.c
===================================================================
RCS file: /big/fsf/rsync/src-cvs/src/gdb/arm-tdep.c,v
retrieving revision 1.156
diff -u -p -r1.156 arm-tdep.c
--- arm-tdep.c	13 Jan 2004 21:38:45 -0000	1.156
+++ arm-tdep.c	16 Jan 2004 03:37:46 -0000
@@ -2689,6 +2689,21 @@ arm_coff_make_msymbol_special(int val, s
     MSYMBOL_SET_SPECIAL (msym);
 }
 
+static void
+arm_write_pc (CORE_ADDR pc, ptid_t ptid)
+{
+  write_register_pid (ARM_PC_REGNUM, pc, ptid);
+
+  /* If necessary, set the T bit.  */
+  if (arm_apcs_32)
+    {
+      CORE_ADDR val = read_register_pid (ARM_PS_REGNUM, ptid);
+      if (arm_pc_is_thumb (pc))
+	write_register_pid (ARM_PS_REGNUM, val | 0x20, ptid);
+      else
+	write_register_pid (ARM_PS_REGNUM, val & ~(CORE_ADDR) 0x20, ptid);
+    }
+}
 \f
 static enum gdb_osabi
 arm_elf_osabi_sniffer (bfd *abfd)
@@ -2850,6 +2865,8 @@ arm_gdbarch_init (struct gdbarch_info in
   set_gdbarch_deprecated_sizeof_call_dummy_words (gdbarch, 0);
 
   set_gdbarch_push_dummy_call (gdbarch, arm_push_dummy_call);
+
+  set_gdbarch_write_pc (gdbarch, arm_write_pc);
 
   /* Frame handling.  */
   set_gdbarch_unwind_dummy_id (gdbarch, arm_unwind_dummy_id);