FYI: dwarf reader and typedefs

[Tom Tromey <tromey at redhat dot com>]

I'm checking this in.

This is another patch from the charset branch.  After talking with
Joel on irc, I decided to scale back my efforts to split the patch up;
but this part is still relatively independent of the bulk of the
charset work, and I thought it would be good to put it in separately.

This changes the dwarf reader to give types their typedef name.
Before this patch, a lookup of "wchar_t" could yield a type whose name
was "unsigned short"; after the patch, the resulting type is a typedef
whose name is "wchar_t".  This makes our internal model a bit more
consistent, and also lets gdb recognize some types by name (in
particular, wchar_t, which is a typedef in C).

The patch includes a couple other parts, to fix regressions we found
after making the dwarf2read.c change.  I also did some looking with
stabs, and as far as I can tell, the stabs reader already works this
way.

This was built and regtested on x86-64 (compile farm).

Tom

2009-03-20  Tom Tromey  <tromey@redhat.com>
	    Jan Kratochvil  <jan.kratochvil@redhat.com>

	* dwarf2read.c (process_die): Handle DW_TAG_typedef.
	* eval.c (evaluate_subexp_standard) <OP_TYPE>: Strip a single
	typedef.
	* ada-lang.c (decode_packed_array_type): Call CHECK_TYPEDEF on the
	SYMBOL_TYPE result.
	* ada-typeprint.c (print_array_type): Do the NULL check
	unconditionally.

Index: ada-lang.c
===================================================================
RCS file: /cvs/src/src/gdb/ada-lang.c,v
retrieving revision 1.198
diff -u -r1.198 ada-lang.c
--- ada-lang.c	13 Mar 2009 02:30:55 -0000	1.198
+++ ada-lang.c	20 Mar 2009 21:52:38 -0000
@@ -1783,6 +1783,7 @@
       return NULL;
     }
   shadow_type = SYMBOL_TYPE (sym);
+  CHECK_TYPEDEF (shadow_type);
 
   if (TYPE_CODE (shadow_type) != TYPE_CODE_ARRAY)
     {
Index: ada-typeprint.c
===================================================================
RCS file: /cvs/src/src/gdb/ada-typeprint.c,v
retrieving revision 1.25
diff -u -r1.25 ada-typeprint.c
--- ada-typeprint.c	19 Feb 2009 23:59:27 -0000	1.25
+++ ada-typeprint.c	20 Mar 2009 21:52:38 -0000
@@ -357,16 +357,17 @@
   bitsize = 0;
   fprintf_filtered (stream, "array (");
 
+  if (type == NULL)
+    {
+      fprintf_filtered (stream, _("<undecipherable array type>"));
+      return;
+    }
+
   n_indices = -1;
   if (show < 0)
     fprintf_filtered (stream, "...");
   else
     {
-      if (type == NULL)
-        {
-          fprintf_filtered (stream, _("<undecipherable array type>"));
-          return;
-        }
       if (ada_is_simple_array_type (type))
 	{
 	  struct type *range_desc_type =
Index: dwarf2read.c
===================================================================
RCS file: /cvs/src/src/gdb/dwarf2read.c,v
retrieving revision 1.296
diff -u -r1.296 dwarf2read.c
--- dwarf2read.c	9 Mar 2009 18:53:48 -0000	1.296
+++ dwarf2read.c	20 Mar 2009 21:52:39 -0000
@@ -2849,6 +2849,7 @@
 
     case DW_TAG_base_type:
     case DW_TAG_subrange_type:
+    case DW_TAG_typedef:
       /* Add a typedef symbol for the type definition, if it has a
          DW_AT_name.  */
       new_symbol (die, read_type_die (die, cu), cu);
Index: eval.c
===================================================================
RCS file: /cvs/src/src/gdb/eval.c,v
retrieving revision 1.106
diff -u -r1.106 eval.c
--- eval.c	21 Feb 2009 16:14:47 -0000	1.106
+++ eval.c	20 Mar 2009 21:52:39 -0000
@@ -2475,7 +2475,17 @@
       if (noside == EVAL_SKIP)
         goto nosideret;
       else if (noside == EVAL_AVOID_SIDE_EFFECTS)
-        return allocate_value (exp->elts[pc + 1].type);
+	{
+	  struct type *type = exp->elts[pc + 1].type;
+	  /* If this is a typedef, then find its immediate target.  We
+	     use check_typedef to resolve stubs, but we ignore its
+	     result because we do not want to dig past all
+	     typedefs.  */
+	  check_typedef (type);
+	  if (TYPE_CODE (type) == TYPE_CODE_TYPEDEF)
+	    type = TYPE_TARGET_TYPE (type);
+	  return allocate_value (type);
+	}
       else
         error (_("Attempt to use a type name as an expression"));