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To: Vladimir Prus <ghost@cs.msu.su>
Cc: gdb-patches@sources.redhat.com
Subject: Re: MI: fix base members in references
References: <200611291555.42209.ghost@cs.msu.su> <el3rsa$crg$1@sea.gmane.org>
From: Jim Blandy <jimb@codesourcery.com>
Date: Tue, 05 Dec 2006 21:32:00 -0000
In-Reply-To: <el3rsa$crg$1@sea.gmane.org> (Vladimir Prus's message of "Tue, 05 Dec 2006 16:23:16 +0300")
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Vladimir Prus <ghost@cs.msu.su> writes:
> *PING*? This is one-liner, and causes no regressions, so should be
> non-controversial.

(By the way --- it's handy to include a link to the post with the
patch, or ideally the patch itself.)

Here's the original patch:

Index: varobj.c
===================================================================
RCS file: /cvs/src/src/gdb/varobj.c,v
retrieving revision 1.62
diff -u -p -r1.62 varobj.c
--- varobj.c	29 Nov 2006 06:41:13 -0000	1.62
+++ varobj.c	29 Nov 2006 12:51:53 -0000
@@ -2428,8 +2428,9 @@ cplus_value_of_child (struct varobj *par
 	    {
 	      struct value *temp = NULL;
 
+	      /* No special processing for references is needed --
+		 value_cast below handles references.  */
 	      if (TYPE_CODE (value_type (parent->value)) == TYPE_CODE_PTR
-		  || TYPE_CODE (value_type (parent->value)) == TYPE_CODE_REF)
 		{
 		  if (!gdb_value_ind (parent->value, &temp))
 		    return NULL;

How should this behave if parent->value is a reference to a pointer?
Shouldn't it follow the ref, and then behave the same as when it's a
pointer?  If so, then the fix would be something like this instead
(not that I understand this code):

*** varobj.c	29 Nov 2006 15:47:40 -0800	1.62
--- varobj.c	05 Dec 2006 13:31:51 -0800	
***************
*** 2426,2441 ****
  	  /* Baseclass */
  	  if (parent->value != NULL)
  	    {
! 	      struct value *temp = NULL;
  
! 	      if (TYPE_CODE (value_type (parent->value)) == TYPE_CODE_PTR
! 		  || TYPE_CODE (value_type (parent->value)) == TYPE_CODE_REF)
  		{
! 		  if (!gdb_value_ind (parent->value, &temp))
  		    return NULL;
  		}
- 	      else
- 		temp = parent->value;
  
  	      if (temp != NULL)
  		{
--- 2426,2439 ----
  	  /* Baseclass */
  	  if (parent->value != NULL)
  	    {
! 	      struct value *temp = coerce_ref (parent->value);
  
! 	      if (TYPE_CODE (value_type (temp)) == TYPE_CODE_PTR
! 		  || TYPE_CODE (value_type (temp)) == TYPE_CODE_REF)
  		{
! 		  if (!gdb_value_ind (temp, &temp))
  		    return NULL;
  		}
  
  	      if (temp != NULL)
  		{