Date: Mon, 15 Mar 1999 10:08:55 -0800 (PST) From: John Polstra <jdp@polstra.com> To: Sheldon Hearn <sheldonh@iafrica.com> Cc: cvs-all@FreeBSD.org, cvs-committers@FreeBSD.org, John Polstra <jdp@FreeBSD.org>, Dmitrij Tejblum <dima@tejblum.dnttm.rssi.ru> Subject: Re: cvs commit: src/lib/csu/i386-elf Makefile crtbegin.c crtend. Message-ID: <XFMail.990315100855.jdp@polstra.com> In-Reply-To: <47124.921493522@axl.noc.iafrica.com>
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Sheldon Hearn wrote:
> On Sun, 14 Mar 1999 21:15:57 +0300, Dmitrij Tejblum wrote:
>
>> Ah! This is the thing that breaks world (namely, groff) with -O3. gcc
>> eliminate the "unused" code completely, and you cannot fix it by
>> -Wno-unused or by __unused.
>
> Does this relate at all to PR bin/10522?
No, that's something different. It's a known limitation of gcc that
some spurious warnings can come out when no optimization is used.
(And some constructs that should cause valid warnings can be missed.)
That's why it's a bad idea to use -Werror anywhere, any time. I see
several possible solutions:
1. Outlaw the use of -Werror in any makefiles under /usr/src, and
add a comment warning about its use in /etc/make.conf.
2. Add some magic to the /usr/share/mk/files to silently remove
-Werror from CFLAGS if no optimization is used. I'm pretty sure this
is feasible, modulo bugs in make. Here's a barely tested possibility:
_OFLAG:=-O0
.for i in ${CFLAGS:M-O*}
_OFLAG:=${i}
.endfor
.if ${_OFLAG} == "-O0"
CFLAGS:=${CFLAGS:N-Werror}
.endif
3. Like #2, but backwards: silently add -O if -Werror is used and no
optimization was specified.
4. Modify the compiler to do #2 or #3.
I'd personally prefer #1 (because -Werror is a misguided idea IMHO) or
#2 (because it solves the problem without police). I don't like #3,
because it changes the code that's emitted. I don't like #4, because
any divergence from standard compilers is a maintenance hassle.
John
---
John Polstra jdp@polstra.com
John D. Polstra & Co., Inc. Seattle, Washington USA
"Self-interest is the aphrodisiac of belief." -- James V. DeLong
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