Re: [PATCH] m32c-tdep.c: Add virtual_frame_pointer function

[Corinna Vinschen <vinschen at redhat dot com>]

On Jun 28 22:34, Daniel Jacobowitz wrote:
> On Wed, Jun 28, 2006 at 11:29:41PM +0200, Mark Kettenis wrote:
> > > Date: Wed, 28 Jun 2006 15:29:18 +0200
> > > From: Corinna Vinschen <XXXXXXXX@XXXXXX.XXX>
> > > 
> > > the below patch adds a virtual_frame_pointer function to m32c-tdep.c,
> > > to avoid that legacy_virtual_frame_pointer is called from tracepoint.c,
> > > [...]
> > 
> > You probably should change legacy_virtual_frame_pointer to check for
> > SP_REGNUM < NUM_REGS + NUM_PSEUDO_REGS instead.
> 
> Neither, I don't think!  Did this just turn up in a testsuite run, or
> did you actually try it with tracepoints, Corinna?

It fixed the testsuite run.  I assumed that the gdb.trace testsuite
is testing..., well, tracepoints.

> The assertion seems correct to me.  The frame register number is going
> to get sent to the remote target system.  We shouldn't ever do that for
> pseudo registers, because the target probably doesn't know how to
> generate their contents... otherwise they'd be real registers.

I see the point.  I rewrote the m32c_virtual_frame_pointer function to
return a valid register/offset pair from the banked fb resp. sp
registers.  Does that look ok?


Corinna


	* m32c-tdep.c (m32c_banked_register): New function.
	(m32c_banked_read): Use m32c_banked_register function to evaluate
	real register number.
	(m32c_banked_write): Ditto.
	(m32c_virtual_frame_pointer): New function.
	(m32c_gdbarch_init): Add set_gdbarch_virtual_frame_pointer call.


Index: m32c-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/m32c-tdep.c,v
retrieving revision 1.1
diff -u -p -r1.1 m32c-tdep.c
--- m32c-tdep.c	20 Apr 2006 23:18:48 -0000	1.1
+++ m32c-tdep.c	29 Jun 2006 10:46:38 -0000
@@ -340,6 +340,13 @@ m32c_read_flg (struct regcache *cache)
 }
 
 
+/* Evaluate the real register number of a banked register.  */
+m32c_banked_register (struct m32c_reg *reg, struct regcache *cache)
+{
+  return ((m32c_read_flg (cache) & reg->n) ? reg->ry : reg->rx);
+}
+
+
 /* Move the value of a banked register from CACHE to BUF.
    If the value of the 'flg' register in CACHE has any of the bits
    masked in REG->n set, then read REG->ry.  Otherwise, read
@@ -347,8 +354,7 @@ m32c_read_flg (struct regcache *cache)
 static void
 m32c_banked_read (struct m32c_reg *reg, struct regcache *cache, void *buf)
 {
-  struct m32c_reg *bank_reg
-    = ((m32c_read_flg (cache) & reg->n) ? reg->ry : reg->rx);
+  struct m32c_reg *bank_reg = m32c_banked_register (reg, cache);
   regcache_raw_read (cache, bank_reg->num, buf);
 }
 
@@ -360,8 +366,7 @@ m32c_banked_read (struct m32c_reg *reg, 
 static void
 m32c_banked_write (struct m32c_reg *reg, struct regcache *cache, void *buf)
 {
-  struct m32c_reg *bank_reg
-    = ((m32c_read_flg (cache) & reg->n) ? reg->ry : reg->rx);
+  struct m32c_reg *bank_reg = m32c_banked_register (reg, cache);
   regcache_raw_write (cache, bank_reg->num, (const void *) buf);
 }
 
@@ -2475,6 +2480,40 @@ m32c_m16c_pointer_to_address (struct typ
   return ptr;
 }
 
+void
+m32c_virtual_frame_pointer (CORE_ADDR pc,
+			    int *frame_regnum,
+			    LONGEST *frame_offset)
+{
+  char *name;
+  CORE_ADDR func_addr, func_end, sal_end;
+  struct m32c_prologue p;
+
+  struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch);
+  
+  if (!find_pc_partial_function (pc, &name, &func_addr, &func_end))
+    internal_error (__FILE__, __LINE__, _("No virtual frame pointer available"));
+
+  m32c_analyze_prologue (current_gdbarch, func_addr, pc, &p);
+  switch (p.kind)
+    {
+    case prologue_with_frame_ptr:
+      *frame_regnum = m32c_banked_register (tdep->fb, current_regcache)->num;
+      *frame_offset = p.frame_ptr_offset;
+      break;
+    case prologue_sans_frame_ptr:
+      *frame_regnum = m32c_banked_register (tdep->sp, current_regcache)->num;
+      *frame_offset = p.frame_size;
+      break;
+    default:
+      *frame_regnum = m32c_banked_register (tdep->sp, current_regcache)->num;
+      *frame_offset = 0;
+      break;
+    }
+  /* Sanity check */
+  if (*frame_regnum > NUM_REGS)
+    internal_error (__FILE__, __LINE__, _("No virtual frame pointer available"));
+}
 
 
 /* Initialization.  */
@@ -2539,6 +2578,8 @@ m32c_gdbarch_init (struct gdbarch_info i
   /* Trampolines.  */
   set_gdbarch_skip_trampoline_code (arch, m32c_skip_trampoline_code);
 
+  set_gdbarch_virtual_frame_pointer (arch, m32c_virtual_frame_pointer);
+
   return arch;
 }
 

-- 
Corinna Vinschen
Cygwin Project Co-Leader
Red Hat