Date: 13 Jun 2006 02:01:22 -0000 From: Andrew Reilly <andrew-freebsd@areilly.bpc-users.org> To: FreeBSD-gnats-submit@FreeBSD.org Subject: amd64/98893: cc error at -O2 on amd64/6-STABLE compiling port ucspi-tcp Message-ID: <20060613020122.24742.qmail@areilly.bpc-users.org> Resent-Message-ID: <200606130210.k5D2AIRV073111@freefall.freebsd.org>
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>Number: 98893
>Category: amd64
>Synopsis: cc error at -O2 on amd64/6-STABLE compiling port ucspi-tcp
>Confidential: no
>Severity: serious
>Priority: medium
>Responsible: freebsd-amd64
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Tue Jun 13 02:10:18 GMT 2006
>Closed-Date:
>Last-Modified:
>Originator: Andrew Reilly
>Release: FreeBSD 6.1-STABLE amd64
>Organization:
>Environment:
System: FreeBSD duncan.reilly.home 6.1-STABLE FreeBSD 6.1-STABLE #4: Mon Jun 12 13:57:57 EST 2006 root@:/usr/obj/usr/src/sys/DUNCAN amd64
machine is an AMD64-X2-4200+
/etc/make.conf exists but does not set or change CFLAGS
>Description:
tcpserver, from the port sysutils/ucspi-tcp, built as
normal, fails with the error message:
"tcpserver: fatal: temporarily unable to figure out IP
address for 0.0.0.0: file does not exist"
Debugging shows that this is the result of the following
line in dns_rcrw.c always returning -1:
if (gethostname(host,sizeof host) == -1) return -1;
Now, ENOFILE ("file does not exist") is not a valid
errno return from gethostname, and separate testing
shows that gethostname() runs just fine. Indeed, this
piece of kdump output shows that it was called, and
returned 0, as expected:
13441 tcpserver CALL open(0x4086fe,0x4,0x40)
13441 tcpserver NAMI "/etc/resolv.conf"
13441 tcpserver RET open -1 errno 2 No such file or directory
13441 tcpserver CALL __sysctl(0x7fffffffe3b8,0x2,0x7fffffffe3d0,0x7fffffffe3b0,0,0)
13441 tcpserver RET __sysctl 0
13441 tcpserver CALL write(0x2,0x50b960,0x5f)
13441 tcpserver GIO fd 2 wrote 95 bytes
"tcpserver: fatal: temporarily unable to figure out IP address for 0.0.\
0.0: file does not exist
"
13441 tcpserver RET write 95/0x5f
13441 tcpserver CALL exit(0x6f)
(gethostname is that __sysctl. errno is no-doubt still
set to ENOFILE from the failed open of /etc/resolv.conf.)
So: the only conclusion is that the compiler flubbed the
comparison of the return value against -1, and returned
(-1) anyway. Unfortunately, the code produced by cc (gcc3.4.4)
at -O2 bears so little resemblance to the source that I
can't follow it, to point this out explicitly (and
neither can objdump -S...)
The code works fine if the gethostname call is made
without checking the return value (it can't reasonably
fail, anyway).
It also works fine if the default -O2 is overridden with
-O, which is what I'm recommending here.
It also works fine with default CFLAGS (-O2
-fno-strict-aliasing -pipe) with CC=gcc41, built from ports.
>How-To-Repeat:
cd /usr/ports/sysutils/ucspi-tcp
sudo make
cd work/ucspi-tcp-0.88
./tcpserver 0 2525 /bin/cat
>Fix:
Well, this is a work-around for this particular case.
I'm surprised that this could be the only program that
has trouble at -O2, given the zillions of lines of code
in the system and ports that seems to be running OK. So
I doubt my diagnosis of a compiler bug, but I can't
think of an alternative. The code itself looks
perfectly fine.
--- Makefile.orig Tue Jun 13 10:55:47 2006
+++ Makefile Tue Jun 13 11:07:14 2006
@@ -63,7 +63,7 @@
post-configure:
@${ECHO_CMD} ${PREFIX} > ${WRKSRC}/conf-home
- @${ECHO_CMD} ${CC} ${CFLAGS} > ${WRKSRC}/conf-cc
+ @${ECHO_CMD} ${CC} -O -fno-strict-aliasing -pipe > ${WRKSRC}/conf-cc
@${ECHO_CMD} ${CC} -s > ${WRKSRC}/conf-ld
do-install:
Alternatively, cd /usr/ports/sysutils/ucspi-tcp; sudo
make CC=gcc41.
>Release-Note:
>Audit-Trail:
>Unformatted:
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