Date: Sat, 30 Jan 2016 05:58:02 -0800 From: Mark Millard <markmi@dsl-only.net> To: Roman Divacky <rdivacky@vlakno.cz> Cc: FreeBSD PowerPC ML <freebsd-ppc@freebsd.org>, FreeBSD Toolchain <freebsd-toolchain@freebsd.org> Subject: Re: clang 3.8.0 based powerpc (32 bit) buildworld runs on a PowerMac! [problems found] Message-ID: <E2771C4A-4CC9-4394-A2D7-10CCB5F13BDE@dsl-only.net> In-Reply-To: <20160130112913.GA7950@vlakno.cz> References: <DEF41968-FFC4-417D-A31A-E392CB888C35@dsl-only.net> <55814789-0489-48B5-867C-F678AE4EA5FF@dsl-only.net> <20160130112913.GA7950@vlakno.cz>
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On 2016-Jan-30, at 3:29 AM, Roman Divacky <rdivacky at vlakno.cz> wrote:
> Can you file a bug in llvm bugzilla?
I could try for the example code. But I'd like to make the example more =
self contained first, avoiding snprintf from library code and hopefully =
with a much smaller, simpler implementation involved than the =
very-general library code.
Separately: I'm not sure any llvm folks are going to have a way to test =
unless someone shows the problem outside a FreeBSD context. =
powerpc-clang (32-bit) based FreeBSD buildworld's are not exactly a =
normal context at this point.
My files with powerpc (32-bit) tied differences from svn for =
projects/clang380-import -r294962 are:
Index: /media/usr/src/sys/boot/powerpc/Makefile
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
--- /media/usr/src/sys/boot/powerpc/Makefile (revision 294962)
+++ /media/usr/src/sys/boot/powerpc/Makefile (working copy)
@@ -1,5 +1,9 @@
# $FreeBSD$
=20
-SUBDIR=3D boot1.chrp kboot ofw ps3 uboot
+SUBDIR=3D boot1.chrp
+.if ${MACHINE_ARCH} =3D=3D "powerpc64"
+SUBDIR+=3D kboot
+.endif
+SUBDIR+=3D ofw ps3 uboot
=20
.include <bsd.subdir.mk>
Index: /media/usr/src/sys/conf/Makefile.powerpc
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
--- /media/usr/src/sys/conf/Makefile.powerpc (revision 294962)
+++ /media/usr/src/sys/conf/Makefile.powerpc (working copy)
@@ -35,7 +35,11 @@
=20
INCLUDES+=3D -I$S/contrib/libfdt
=20
+.if ${COMPILER_TYPE} =3D=3D "gcc"
CFLAGS+=3D -msoft-float -Wa,-many
+.else
+CFLAGS+=3D -msoft-float
+.endif
=20
# Build position-independent kernel
CFLAGS+=3D -fPIC
Index: /media/usr/src/sys/conf/kern.mk
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
--- /media/usr/src/sys/conf/kern.mk (revision 294962)
+++ /media/usr/src/sys/conf/kern.mk (working copy)
@@ -144,7 +144,11 @@
#
.if ${MACHINE_CPUARCH} =3D=3D "powerpc"
CFLAGS+=3D -mno-altivec
+.if ${COMPILER_TYPE} =3D=3D "clang" && ${COMPILER_VERSION} < 30800
CFLAGS.clang+=3D -mllvm -disable-ppc-float-in-variadic=3Dtrue
+.else
+CFLAGS.clang+=3D -msoft-float
+.endif
CFLAGS.gcc+=3D -msoft-float
INLINE_LIMIT?=3D 15000
.endif
Index: /media/usr/src/sys/conf/kmod.mk
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
--- /media/usr/src/sys/conf/kmod.mk (revision 294962)
+++ /media/usr/src/sys/conf/kmod.mk (working copy)
@@ -137,8 +137,12 @@
.endif
=20
.if ${MACHINE_CPUARCH} =3D=3D powerpc
+.if ${COMPILER_TYPE} =3D=3D "gcc"
CFLAGS+=3D -mlongcall -fno-omit-frame-pointer
+.else
+CFLAGS+=3D -fno-omit-frame-pointer
.endif
+.endif
=20
.if ${MACHINE_CPUARCH} =3D=3D mips
CFLAGS+=3D -G0 -fno-pic -mno-abicalls -mlong-calls
(I can not actually buildkernel for powerpc via clang 3.8.0. Still some =
of the above is for the kernel context.)
src.conf content:
KERNCONF=3DGENERICvtsc-NODEBUG
TARGET=3Dpowerpc
TARGET_ARCH=3Dpowerpc
#
WITH_FAST_DEPEND=3D
WITH_LIBCPLUSPLUS=3D
WITH_BOOT=3D
WITH_BINUTILS_BOOTSTRAP=3D
WITH_CLANG_BOOTSTRAP=3D
WITH_CLANG=3D
WITH_CLANG_IS_CC=3D
WITH_CLANG_FULL=3D
WITH_CLANG_EXTRAS=3D
#
# lldb requires missing atomic 8-byte operations for powerpc (non-64)
WITHOUT_LLDB=3D
#
WITHOUT_LIB32=3D
WITHOUT_GCC_BOOTSTRAP=3D
WITHOUT_GCC=3D
WITHOUT_GCC_IS_CC=3D
WITHOUT_GNUCXX=3D
#
NO_WERROR=3D
MALLOC_PRODUCTION=3D
#
WITH_DEBUG_FILES=3D
On Sat, Jan 30, 2016 at 03:00:26AM -0800, Mark Millard wrote:
> I got around to trying some more use of the 3.8.0 clang based world on =
powerpc (32 bit) (now -r294962 based) and ran into:
>=20
> A) Segmentation faults during signal handlers in syslogd, nfsd, =
mountd, and (for SIGNFO) make.
>=20
> B) ls sometimes segmentation faulting
>=20
> C) make -j 6 buildworld segmentation faulting in make eventually but =
make buildworld works.
>=20
> I have reduced (A) to a simple program that demonstrates the behavior:
>=20
>> # more sig_snprintf_use_test.c=20
>> #include <stdio.h>
>> #include <signal.h>
>>=20
>> volatile sig_atomic_t sat =3D 0;
>>=20
>> void
>> handler(int sig)
>> {
>> char uidbuf[32];
>> (void) snprintf(uidbuf, sizeof uidbuf, "%d", 10);
>> sat =3D uidbuf[0];
>> }
>>=20
>> int
>> main(void)
>> {
>> if (signal(SIGINT, handler) !=3D SIG_ERR) raise(SIGINT);
>> return sat;
>> }
>=20
>> # ./a.out
>> Segmentation fault (core dumped)
>> # /usr/local/bin/gdb a.out /var/crash/a.out.1510.core
>> GNU gdb (GDB) 7.10 [GDB v7.10 for FreeBSD]
> . . .
>> warning: Unexpected size of section `.reg2/100167' in core file.
>> #0 0x419a89c8 in memcpy (dst0=3D0xffffd734, src0=3D<optimized out>, =
length=3D<optimized out>) at /usr/src/lib/libc/string/bcopy.c:124
>> 124 TLOOP1(*--dst =3D *--src);
>> (gdb) bt
>> #0 0x419a89c8 in memcpy (dst0=3D0xffffd734, src0=3D<optimized out>, =
length=3D<optimized out>) at /usr/src/lib/libc/string/bcopy.c:124
>> #1 0x419a3984 in __sfvwrite (fp=3D<optimized out>, uio=3D<optimized =
out>) at /usr/src/lib/libc/stdio/fvwrite.c:128
>> #2 0x41934468 in __sprint (fp=3D<optimized out>, uio=3D<optimized =
out>, locale=3D<optimized out>) at =
/usr/src/lib/libc/stdio/vfprintf.c:164
>> #3 io_flush (iop=3D<optimized out>, locale=3D<optimized out>) at =
/usr/src/lib/libc/stdio/printfcommon.h:155
>> #4 __vfprintf (fp=3D<optimized out>, locale=3D<optimized out>, =
fmt0=3D<optimized out>, ap=3D<optimized out>) at =
/usr/src/lib/libc/stdio/vfprintf.c:1020
>> #5 0x4199c644 in snprintf (str=3D0xffffd734 "", n=3D<optimized out>, =
fmt=3D0x1800850 "%d") at /usr/src/lib/libc/stdio/snprintf.c:72
>> #6 0x01800708 in handler ()
>> Backtrace stopped: Cannot access memory at address 0xffffd760
>=20
> (The "Unexpected size . . ." is a known problem in powerpc land at =
this point, not tied to clang 3.8.0 .)
>=20
> The syslogd, nfsd, mountd, and SIGINFO-related make backtraces are =
similar. I got the program above from simplifying the mountd failure =
context.
>=20
> A direct call, handler(0), does not get the segmentation fault.
>=20
> I'll note that in C the handler calling snprintf or other such is a =
no-no for the general case: only abort(), _Exit(), or signal() as of C99 =
as I understand. But the restriction is not true of use of raise so the =
small program is still valid C99 code. Of course it appears FreeBSD =
allows more than C99 does in this area.
>=20
> I've not yet investigated what the original signals are in syslogd, =
nfsd, or mountd. They may well indicate another problem.
>=20
>=20
> I've not gotten as far classifying (B) or (C) as well.
>=20
> (B) is a xo_emit context each time so far (so C elipsis use again, =
like (A)) but no signal handler seems to be active. It stops in =
xo_format_string_direct. My attempts at simpler code have not produced =
the problem so far.
>=20
> (C) is such that GDB 7.10 reports "previous frame to this frame =
(corrupt stack?)" or otherwise gives up. It shows Var_Value called by =
Make_Update before reporting that. gdb 6.1.1 shows more after that: =
JobFinish, JobReapChild, Job_CatchChildern, Job_CatchOutput, Make_Run, =
main). SIGCHLD or other such use may well be involved here.
>=20
>=20
> =3D=3D=3D
> Mark Millard
> markmi at dsl-only.net
>=20
> On 2016-Jan-19, at 2:35 AM, Mark Millard <markmi@dsl-only.net> wrote:
>=20
> I now have an SSD that contains:
>=20
> 0) installkernel material from a gcc 4.2.1 based buildkernel
>=20
> 1) installworld material from a clang 3.8.0 based buildworld
> (clang 3.8.0, libc++, etc.)
>=20
> It boots and seems to be operating fine after booting --in both a G5 =
and a G4 PowerMac.
>=20
> Apparently the clang code generation has been updated to not require =
an explicit -mlongcall. I had to remove those since clang rejects them =
on command lines. It linked without complaint (and later seems to be =
running fine). (I've seen llvm review notes mentioning the "medium =
model" or some phrase like that for powerpc.)
>=20
> (I've not been able to buildkernel yet for powerpc (non-64) from my =
amd64 environment: rejected command lines for other issues. Thus the =
current limitation to buildworld.)
>=20
>=20
>=20
> To get to (1) I did the following sort of sequence:
> (The first few steps deal with other issues in order to have =
sufficient context.)
>=20
>=20
> A) Started by installing the latest powerpc (non-64) snapshot.
> ( =
http://ftp1.freebsd.org/pub/FreeBSD/snapshots/ISO-IMAGES/11.0/FreeBSD-11.0=
-CURRENT-powerpc-20160113-r293801-disc1.iso )
>=20
> (I had to use a PowerMac with video hardware that vt would handle.)
> (Basic display, no X-windows involvement here.)
>=20
>=20
> B) Rebuild, including using my usual kernel configuration that has
> both vt and sc. I did this based on projects/clang380-import
> -r294201 /usr/src but still using gcc 4.2.1 (native on the
> PowerMac). The configuration turns off kernel debugging extras too.
>=20
>=20
> C) installkernel, installworld, etc., set to use sc instead of vt, and =
rebooted.
>=20
> (As of this I could use the SSD in more PowerMacs by using sc instead =
of vt via a /boot/loader.conf assignment.)
>=20
>=20
> D) dump/restore the file systems to another SSD (after partitioning =
it).
> Adjust the host name and the like on the copy.
>=20
> (This copy later ends up having new installworld materials overlaid.)
>=20
>=20
> E) In a projects/clang380-import -r294201 amd64 environment, =
buildworld for
> TARGET_ARCH=3Dpowerpc . WITH_LIBCPLUSPLUS=3D and clang related =
material built,
> gcc 4.2.1 related material not built. WITH_BOOT=3D as well. I choose
> WITHOUT_DEBUG=3D and WITHOUT_DEBUG_FILES=3D . (I've not tried =
enabling them yet.)
> binutils is not from ports.
>=20
>=20
> F) Use DESTDIR=3D with installworld to an initially empty directory =
tree. tar the tree.
>=20
>=20
> G) Transfer the tar file to the PowerMac. Mount the to-be-updated SSD =
to
> /mnt and /mnt/var. After chflags -R noschg on /mnt and /mnt/var use
> tar xpf to replace things from the buildworld on /mnt and /mnt/var.
>=20
> (This does leave older gcc 4.2.1 related materials in place.)
>=20
> H) Dismounts, shutdown, and then boot from the updated SSD.
>=20
>=20
>=20
> Note: I've never manage to get powerpc64-xtoolchain-gcc/powerpc64-gcc =
to produce working 32-bit code. So I've never gotten this far via that =
path.
>=20
>=20
> =3D=3D=3D
> Mark Millard
> markmi at dsl-only.net
>=20
>=20
> _______________________________________________
> freebsd-toolchain@freebsd.org mailing list
> https://lists.freebsd.org/mailman/listinfo/freebsd-toolchain
> To unsubscribe, send any mail to =
"freebsd-toolchain-unsubscribe@freebsd.org"
=3D=3D=3D
Mark Millard
markmi at dsl-only.net
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