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Re: [PATCH] Objective-C language support.
- From: Michael Snyder <msnyder at redhat dot com>
- To: Andrew Cagney <ac131313 at redhat dot com>
- Cc: Adam Fedor <fedor at doc dot com>, gdb-patches at sources dot redhat dot com
- Date: Mon, 21 Oct 2002 15:26:53 -0700
- Subject: Re: [PATCH] Objective-C language support.
- Organization: Red Hat, Inc.
- References: <3D889A97.firstname.lastname@example.org> <3DA36D31.2947E451@redhat.com> <3DB47D3D.email@example.com>
Andrew Cagney wrote:
> > 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,
> >> +
> FYI, I think these should be renamed to OP_OBJC_xxxx so that it is very
> clear that these have Objective C semantics. Otherwize I think it runs
> the risk of people trying to re-use these operators in other languages.
> This would be consistent with the Ada OPS where I recommended
> OP_ADA_xxxx for the Ada specific extensions to the operator table.
OK with me.
> >> /* 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 */