[RFA/stabs] Fix gdb/280 infinite loop in userdef.exp

[Daniel Jacobowitz <drow at mvista dot com>]

Another problem exposed by the way the stabs reader handles types.  It does
'*type = *xtype' at one point, which dies horribly for qualified types (and
messes up pointer types, too...).  I don't immediately see a way to get rid
of that line, so I made an interface to do the copy correctly.

For reference, that appears to be the only place in GDB this is actually
done.  Other readers must handle forward-referenced types somehow...

Without this patch we enter an infinite loop because the cv-chain is
corrupted.

OK to commit?

-- 
Daniel Jacobowitz                           Carnegie Mellon University
MontaVista Software                         Debian GNU/Linux Developer

2002-02-01  Daniel Jacobowitz  <drow@mvista.com>

	PR gdb/280
	* gdbtypes.c (replace_type): New function.
	* gdbtypes.h (replace_type): Add prototype.
	* stabsread.c (read_type): Use replace_type.

Index: gdbtypes.c
===================================================================
RCS file: /cvs/src/src/gdb/gdbtypes.c,v
retrieving revision 1.38
diff -u -p -r1.38 gdbtypes.c
--- gdbtypes.c	2002/01/22 19:57:40	1.38
+++ gdbtypes.c	2002/02/01 23:48:45
@@ -519,6 +519,32 @@ finish_cv_type (struct type *type)
     }
 }
 
+/* Replace the contents of ntype with the type *type.
+
+   This function should not be necessary, but is due to quirks in the stabs
+   reader.  This should go away.  It does not handle the replacement type
+   being cv-qualified; it could be easily fixed to, but it should go away,
+   remember?  */
+void
+replace_type (struct type *ntype, struct type *type)
+{
+  struct type *cv_chain, *as_chain, *ptr, *ref;
+
+  cv_chain = TYPE_CV_TYPE (ntype);
+  as_chain = TYPE_AS_TYPE (ntype);
+  ptr = TYPE_POINTER_TYPE (ntype);
+  ref = TYPE_REFERENCE_TYPE (ntype);
+
+  *ntype = *type;
+
+  TYPE_POINTER_TYPE (ntype) = ptr;
+  TYPE_REFERENCE_TYPE (ntype) = ref;
+  TYPE_CV_TYPE (ntype) = cv_chain;
+  TYPE_AS_TYPE (ntype) = as_chain;
+
+  finish_cv_type (ntype);
+}
+
 /* Implement direct support for MEMBER_TYPE in GNU C++.
    May need to construct such a type if this is the first use.
    The TYPE is the type of the member.  The DOMAIN is the type
Index: gdbtypes.h
===================================================================
RCS file: /cvs/src/src/gdb/gdbtypes.h,v
retrieving revision 1.25
diff -u -p -r1.25 gdbtypes.h
--- gdbtypes.h	2002/01/20 19:42:04	1.25
+++ gdbtypes.h	2002/02/01 23:48:45
@@ -1062,6 +1062,8 @@ extern struct type *make_cv_type (int, i
 
 extern void finish_cv_type (struct type *);
 
+extern void replace_type (struct type *, struct type *);
+
 extern int address_space_name_to_int (char *);
 
 extern char *address_space_int_to_name (int);
Index: stabsread.c
===================================================================
RCS file: /cvs/src/src/gdb/stabsread.c,v
retrieving revision 1.23
diff -u -p -r1.23 stabsread.c
--- stabsread.c	2002/01/20 19:12:23	1.23
+++ stabsread.c	2002/02/01 23:48:46
@@ -2531,7 +2531,7 @@ again:
 	  }
 	else if (type_size >= 0 || is_string)
 	  {
-	    *type = *xtype;
+	    replace_type (type, xtype);
 	    TYPE_NAME (type) = NULL;
 	    TYPE_TAG_NAME (type) = NULL;
 	  }