Re: [rfa] set processing_current_prefix properly (PR gdb/1520)

[David Carlton <carlton at kealia dot com>]

On Fri, 23 Jan 2004 17:26:03 -0500, Elena Zannoni <ezannoni@redhat.com> said:

> Can you add some of the above comments before the new call to check
> for the specification?

Good idea.  I was just writing a comment like that for another patch
that I'm generating; I'll steal it and modify it accordingly for this
one.

> So the only function that one should call in theory should be
> determine_prefix, while possibly_determine_prefix is only there as a
> worker function? Maybe this should be reflected in the names a bit
> more explicitly. 

Good idea; I'll use determine_prefix_aux.

> ok, modulus those 2 nits.

Thanks, I've committed the attached.

David Carlton
carlton@kealia.com

2004-01-23  David Carlton  <carlton@kealia.com>

	Patch for PR c++/1520:
	* dwarf2read.c (read_func_scope): Set processing_current_prefix
	properly if we have a specification die.
	(determine_prefix_aux): Rename from determine_prefix.
	(determine_prefix): Like the old determine_prefix, but never
	returns NULL.

Index: dwarf2read.c
===================================================================
RCS file: /cvs/src/src/gdb/dwarf2read.c,v
retrieving revision 1.123
diff -u -p -r1.123 dwarf2read.c
--- dwarf2read.c	22 Jan 2004 19:56:54 -0000	1.123
+++ dwarf2read.c	23 Jan 2004 22:39:42 -0000
@@ -774,6 +774,8 @@ static void read_type_die (struct die_in
 
 static char *determine_prefix (struct die_info *die);
 
+static char *determine_prefix_aux (struct die_info *die);
+
 static char *typename_concat (const char *prefix, const char *suffix);
 
 static char *class_name (struct die_info *die);
@@ -2145,6 +2147,8 @@ read_func_scope (struct die_info *die, s
   struct die_info *child_die;
   struct attribute *attr;
   char *name;
+  const char *previous_prefix = processing_current_prefix;
+  struct cleanup *back_to = NULL;
 
   name = dwarf2_linkage_name (die);
 
@@ -2153,6 +2157,40 @@ read_func_scope (struct die_info *die, s
   if (name == NULL || !dwarf2_get_pc_bounds (die, &lowpc, &highpc, cu))
     return;
 
+  if (cu_language == language_cplus)
+    {
+      struct die_info *spec_die = die_specification (die);
+
+	  /* NOTE: carlton/2004-01-23: We have to be careful in the
+	     presence of DW_AT_specification.  For example, with GCC
+	     3.4, given the code
+
+               namespace N {
+	         void foo() {
+		   // Definition of N::foo.
+	         }
+	       }
+
+	     then we'll have a tree of DIEs like this:
+
+	     1: DW_TAG_compile_unit
+               2: DW_TAG_namespace        // N
+                 3: DW_TAG_subprogram     // declaration of N::foo
+               4: DW_TAG_subprogram       // definition of N::foo
+                    DW_AT_specification   // refers to die #3
+
+             Thus, when processing die #4, we have to pretend that
+             we're in the context of its DW_AT_specification, namely
+             the contex of die #3.  */
+	
+      if (spec_die != NULL)
+	{
+	  char *specification_prefix = determine_prefix (spec_die);
+	  processing_current_prefix = specification_prefix;
+	  back_to = make_cleanup (xfree, specification_prefix);
+	}
+    }
+
   lowpc += baseaddr;
   highpc += baseaddr;
 
@@ -2203,6 +2241,10 @@ read_func_scope (struct die_info *die, s
      symbols go in the file symbol list.  */
   if (outermost_context_p ())
     list_in_scope = &file_symbols;
+
+  processing_current_prefix = previous_prefix;
+  if (back_to != NULL)
+    do_cleanups (back_to);
 }
 
 /* Process all the DIES contained within a lexical block scope.  Start
@@ -5969,12 +6011,27 @@ read_type_die (struct die_info *die, str
   do_cleanups (back_to);
 }
 
+/* Return the name of the namespace/class that DIE is defined within,
+   or "" if we can't tell.  The caller should xfree the result.  */
+
+/* NOTE: carlton/2004-01-23: See read_func_scope (and the comment
+   therein) for an example of how to use this function to deal with
+   DW_AT_specification.  */
+
+static char *
+determine_prefix (struct die_info *die)
+{
+  char *prefix = determine_prefix_aux (die);
+
+  return prefix ? prefix : xstrdup ("");
+}
+
 /* Return the name of the namespace/class that DIE is defined
    within, or NULL if we can't tell.  The caller should xfree the
    result.  */
 
 static char *
-determine_prefix (struct die_info *die)
+determine_prefix_aux (struct die_info *die)
 {
   struct die_info *parent;
 
@@ -5989,7 +6046,7 @@ determine_prefix (struct die_info *die)
     }
   else
     {
-      char *parent_prefix = determine_prefix (parent);
+      char *parent_prefix = determine_prefix_aux (parent);
       char *retval;
 
       switch (parent->tag) {