Re: RFC: [patch] Circunvent GCC/GDB problem with (void*) types

[Fernando Nasser <fnasser at redhat dot com>]

Checked in.


Fernando Nasser wrote:
> 
> GDB (or GCC) is recently experiencing a problem where the (void *) types
> are not properly identified with the type name "void" in the target
> type.  As a consequence, Insight is dying if some sequence of operations
> are made on the (void *) variable shown in the variable windows.
> 
> I will notify GDB people about that, but I saw no reason for us to
> depend on the target type name.  The target type being TYPE_CODE_VOID
> should be enough.
> 
> The (char *) target types would need that trick as they are of
> TYPE_CODE_INT type (don't ask me why) but have "char" as the type name.
> However, I saw no reason for disallowing the dereferencing of (char *)
> either.  It looks like a useful feature.  If you do not agree, please
> let me know.
> 
> The attached patch makes Insight work regardless.
> 
> ChangeLog:
> 
>         * varobj.c (c_number_of_children): Check for target type of void*,
>         not the target type name.  Allow dereferencing char*.
> 
> --
> Fernando Nasser
> Red Hat Canada Ltd.                     E-Mail:  fnasser@redhat.com
> 2323 Yonge Street, Suite #300
> Toronto, Ontario   M4P 2C9
> 
>   ------------------------------------------------------------------------
> Index: varobj.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/varobj.c,v
> retrieving revision 1.17
> diff -c -p -r1.17 varobj.c
> *** varobj.c    2001/03/27 20:36:24     1.17
> --- varobj.c    2001/05/02 02:35:16
> *************** c_number_of_children (struct varobj *var
> *** 1761,1767 ****
>       case TYPE_CODE_PTR:
>         /* This is where things get compilcated. All pointers have one child.
>            Except, of course, for struct and union ptr, which we automagically
> !          dereference for the user and function ptrs, which have no children. */
>         switch (TYPE_CODE (target))
>         {
>         case TYPE_CODE_STRUCT:
> --- 1761,1773 ----
>       case TYPE_CODE_PTR:
>         /* This is where things get compilcated. All pointers have one child.
>            Except, of course, for struct and union ptr, which we automagically
> !          dereference for the user and function ptrs, which have no children.
> !          We also don't dereference void* as we don't know what to show.
> !          We can show char* so we allow it to be dereferenced.  If you decide
> !          to test for it, please mind that a little magic is necessary to
> !          properly identify it: char* has TYPE_CODE == TYPE_CODE_INT and
> !          TYPE_NAME == "char" */
> !
>         switch (TYPE_CODE (target))
>         {
>         case TYPE_CODE_STRUCT:
> *************** c_number_of_children (struct varobj *var
> *** 1770,1786 ****
>           break;
> 
>         case TYPE_CODE_FUNC:
>           children = 0;
>           break;
> 
>         default:
> !         /* Don't dereference char* or void*. */
> !         if (TYPE_NAME (target) != NULL
> !             && (STREQ (TYPE_NAME (target), "char")
> !                 || STREQ (TYPE_NAME (target), "void")))
> !           children = 0;
> !         else
> !           children = 1;
>         }
>         break;
> 
> --- 1776,1787 ----
>           break;
> 
>         case TYPE_CODE_FUNC:
> +       case TYPE_CODE_VOID:
>           children = 0;
>           break;
> 
>         default:
> !         children = 1;
>         }
>         break;
> 

-- 
Fernando Nasser
Red Hat Canada Ltd.                     E-Mail:  fnasser@redhat.com
2323 Yonge Street, Suite #300
Toronto, Ontario   M4P 2C9