Re: [PATCH] Objective-C language support.

[Michael Snyder <msnyder@redhat.com>]

Adam Fedor wrote:
> 
> This patch adds Objective-C language support to gdb based upon a patch
> provided by Apple Computer Inc from their version of gdb. Note that the
> patch only contains changes to existing files. New files (objc-lang.h,
> objc-lang.c, objc-exp.y) and a gdb.objc testsuite directory are located at
> 
> ftp://ftp.gnustep.org/pub/gnustep/contrib/gdb-objc-patch.tar.gz

Adam, this bit can't hurt anything, since it just adds some new enum
values.  Only one suggestion -- how about putting OP_THIS and OP_SELF
consecutively, because they're so similar?  Also please hold off on
the export of evaluate_subexp -- let's handle that separately.

Other than that, approved.  Wait a couple days for objections, then
you can commit it.


>         * expression.h: New ops NSSTRING, SELECTOR, MSGCALL, and SELF.

> Index: gdb/expression.h
> ===================================================================
> RCS file: /cvs/src/src/gdb/expression.h,v
> retrieving revision 1.4
> diff -u -p -r1.4 expression.h
> --- gdb/expression.h    1 Aug 2002 17:18:32 -0000       1.4
> +++ gdb/expression.h    17 Sep 2002 19:30:05 -0000
> @@ -181,6 +181,12 @@ enum exp_opcode
>         making three exp_elements.  */
>      OP_FUNCALL,
> 
> +    /* OP_MSGCALL is followed by a string in the next exp_element and then an
> +       integer.  The string is the selector string.  The integer is the number
> +       of arguments to the message call.  That many plus one values are used,
> +       the first one being the object pointer.  This is an Objective C message */
> +    OP_MSGCALL,
> +
>      /* This is EXACTLY like OP_FUNCALL but is semantically different.
>         In F77, array subscript expressions, substring expressions
>         and function calls are  all exactly the same syntactically. They may
> @@ -273,11 +279,17 @@ enum exp_opcode
>      STRUCTOP_STRUCT,
>      STRUCTOP_PTR,
> 
> -    /* C++ */
> -    /* OP_THIS is just a placeholder for the class instance variable.
> +    /* C++: OP_THIS is just a placeholder for the class instance variable.
>         It just comes in a tight (OP_THIS, OP_THIS) pair.  */
>      OP_THIS,
> 
> +    /* Objective C: "@selector" pseudo-operator */
> +    OP_SELECTOR,
> +
> +    /* Objective-C: OP_SELF is just a placeholder for the class instance
> +       variable.  It just comes in a tight (OP_SELF, OP_SELF) pair.  */
> +    OP_SELF,
> +
>      /* OP_SCOPE surrounds a type name and a field name.  The type
>         name is encoded as one element, but the field name stays as
>         a string, which, of course, is variable length.  */
> @@ -305,7 +317,10 @@ enum exp_opcode
>      OP_NAME,
> 
>      /* An unparsed expression.  Used for Scheme (for now at least) */
> -    OP_EXPRSTRING
> +    OP_EXPRSTRING,
> +
> +    /* An Objective C Foundation Class NSString constant */
> +    OP_NSSTRING,
>    };
> 
>  union exp_element
> @@ -369,6 +384,10 @@ enum noside
> 
>  extern struct value *evaluate_subexp_standard
>    (struct type *, struct expression *, int *, enum noside);
> +
> +extern struct value *evaluate_subexp (struct type *, struct expression *,
> +                                     int *, enum noside);
> +
> 
>  /* From expprint.c */
>