Re: [PATCH] Don't optimize code in debug build

From: Junio C Hamano <gitster@pobox.com>
Date: Feb 13, 2011, 19:28 UTC
Message-ID: <7vbp2fybs7.fsf@alter.siamese.dyndns.org>
In-Reply-To: <201102131036.51311.j6t@kdbg.org>

Johannes Sixt <j6t@kdbg.org> writes:

Show 18 quoted lines

>> @@ -262,7 +262,10 @@ endif
>>
>>  # CFLAGS and LDFLAGS are for the users to override from the command line.
>>
>> -CFLAGS = -g -O2 -Wall
>> +CFLAGS = -g -Wall
>> +ifndef DEBUG
>> +CFLAGS += -O2
>> +endif
>>  LDFLAGS =
>>  ALL_CFLAGS = $(CPPFLAGS) $(CFLAGS)
>>  ALL_LDFLAGS = $(LDFLAGS)
>
> Instead of this, you can just write
>
>  CFLAGS = -g -Wall
>
> in your config.mak. Is anything wrong with that?

You then need to feed -O2 from the command line when you are not doing a debugging build. On the other hand, with the current Makefile, you need to feed "-g -O0" from the command line when you are doing a debugging build if you and your debugger get confused when seeing an optimized binary. So neither is a very good solution.

But having to feed DEBUG=Yes when running a debug build is not a good solution either. A single toggle is simply too coarse-grained; the next temptation after applying this patch would be to add

	ifdef DEBUG
        CFLAGS += -DDEBUG
        endif

and from there everything goes downhill. That is the last thing we would want to see happen.

So I would say the current Makefile is just fine as is.