[RFC] add offset support to DWARF2_FRAME_REG_CFA

[Christophe LYON <christophe.lyon@st.com>]

Hi all,

Following a discussion we had back in july, I would like to submit the 
following small patch. It enables to describe that SP = CFA + offset,
rather than only SP = CFA.

It can be used in conjonction with a customized xxx_dwarf2_frame_init_reg().

Regards,

Christophe.


2005-11-22	Christophe Lyon <christophe.lyon@st.com>

	* dwarf2-frame.c: (dwarf2_frame_default_init_reg): Ensure
	default offset between SP and CFA is 0.
	(dwarf2_frame_prev_register): add offset to CFA in order to
	compute SP


Index: dwarf2-frame.c
===================================================================
--- dwarf2-frame.c   (revision 96)
+++ dwarf2-frame.c   (working copy)
@@ -539,7 +542,10 @@
    if (regnum == PC_REGNUM)
      reg->how = DWARF2_FRAME_REG_RA;
    else if (regnum == SP_REGNUM)
-    reg->how = DWARF2_FRAME_REG_CFA;
+    {
+      reg->how = DWARF2_FRAME_REG_CFA;
+      reg->loc.offset = 0;
+    }
  }

  /* Return a default for the architecture-specific operations.  */
@@ -914,7 +920,8 @@
        if (valuep)
         {
           /* Store the value.  */
-         store_typed_address (valuep, builtin_type_void_data_ptr, 
cache->cfa);
+         store_typed_address (valuep, builtin_type_void_data_ptr,
+                              cache->cfa + cache->reg[regnum].loc.offset);
         }
        break;