# [PATCH] Don't optimize code in debug build 4 messages from 2011-02-13 to 2011-02-13. Participants: Piotr Krukowiecki, Johannes Sixt, Junio C Hamano. Thread: https://gitlist.dev/t/26487 ## Piotr Krukowiecki, 2011-02-13 08:32 Subject: [PATCH] Don't optimize code in debug build Message-ID: URL: https://gitlist.dev/e/AANLkTinw7DJ3hP7ACcScHTYy-Dvizq-OxefP6e0dEBbR%40mail.gmail.com ``` Code optimization makes debugging harder. Signed-off-by: Piotr Krukowiecki --- My first patch to this list, so please be gentle ;) Patch fixes most important problem. There are other improvement possible: - "-g" is not needed in normal build IMO, I'd move it to debug - I'd add -O0 -fno-inline to debug too, but maybe it's too gccish (OTOH there's -g already) Makefile | 5 ++++- 1 files changed, 4 insertions(+), 1 deletions(-) diff --git a/Makefile b/Makefile index ade7923..32d3a69 100644 --- a/Makefile +++ b/Makefile @@ -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) -- 1.7.1 -- Piotrek ``` ## Johannes Sixt, 2011-02-13 09:36 Subject: Re: [PATCH] Don't optimize code in debug build Message-ID: <201102131036.51311.j6t@kdbg.org> URL: https://gitlist.dev/e/201102131036.51311.j6t%40kdbg.org In-Reply-To: ``` On Sonntag, 13. Februar 2011, Piotr Krukowiecki wrote: > --- a/Makefile > +++ b/Makefile > @@ -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? -- Hannes ``` ## Piotr Krukowiecki, 2011-02-13 16:26 Subject: Re: [PATCH] Don't optimize code in debug build Message-ID: URL: https://gitlist.dev/e/AANLkTinECgZwFZ0157O-qvYUW1GpJgbsHDekR1WM6gPm%40mail.gmail.com In-Reply-To: ``` (forgot about the list when replying) > On Sun, Feb 13, 2011 at 10:36 AM, Johannes Sixt wrote: >> On Sonntag, 13. Februar 2011, Piotr Krukowiecki wrote: >>> --- a/Makefile >>> +++ b/Makefile >>> @@ -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? Several things: I need to know I should remove -O2, I need to keep in sync with other default options, current default is less useful, it requires me to do extra steps. DEBUG is kind of standard - Makefile already uses it in Windows specific part. I suppose we want to keep consistent. -- Piotrek ``` ## Junio C Hamano, 2011-02-13 19:28 Subject: Re: [PATCH] Don't optimize code in debug build Message-ID: <7vbp2fybs7.fsf@alter.siamese.dyndns.org> URL: https://gitlist.dev/e/7vbp2fybs7.fsf%40alter.siamese.dyndns.org In-Reply-To: <201102131036.51311.j6t@kdbg.org> ``` Johannes Sixt writes: >> @@ -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. ```