Re: [PATCH] Objective-C language support.

Andrew Cagney
2002-10-21T22:18:39Z

> 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.

Andrew

>> /* 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 */
>>
>
>