NetBSD/doc/HACKS

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# $NetBSD: HACKS,v 1.1 2002/09/21 08:17:37 lukem Exp $
#
# This file is intended to document workarounds for currently unsolved
# (mostly) compiler bugs.
#
# Format:
# hack title
# cdate creation date
# mdate mod date
# who responsible developer
# port ...
# affected ports, space separated, if not "all"
# file affected file : revision : line from : line to
# affected files and revision and line numbers describing hack
# multiple lines if necessary.
# pr NNNN ...
# problem reports this hack works around, if known. Space
# separated.
# regress src/regress/directory/where/test/found
# regression test directories, if available.
# descr
# insert short informal description (multi-line). (Longer ones
# should be in the PR database. More formal descriptions might
# be in the regress tree. See above).
# kcah
# closing bracket.
#
# this is a comment.
hack specific knowledge of xterm escapes in curses code
cdate Wed, 11 Sep 2002 18:23:25 +0300
who jdc
port all
file lib/libcurses/setterm.c : 1.33
descr
Recognise that "\E[m" will turn off all attributes for xterm-like
terminals. Without this hack, we can't tell when turning off one
attribute affects another (which we check by comparing sequences).
kcah
hack gcc 2.95/vax cannot handle __builtin_ffs()
cdate Fri Aug 23 21:31:15 CEST 2002
who ragge
port vax
file sys/lib/libkern/libkern.h : 1.42
descr
__builtin_ffs() is ifdef'd away if __vax__. Matt Thomas has added
this feature to GCC 3 so it can be removed when switching.
kcah
hack gcc 2.95.3 -O2 bug
cdate Sun Jan 6 23:17:28 UTC 2002
who lukem
port alpha
file sbin/newfs/mkfs.c : (all?)
pr 15156
descr
newfs built with gcc -O2 dumps core part-way through.
using -O1 avoids the problem
kcah
hack binutil-2.11-sparc64-pltrela
mdate 14 Aug 2001
who eeh
port sparc64
file libexec/ld.elf_so/reloc.c: 1.41 : 597 : 619
descr
The first for PLT entries are reserved. There is some disagreement
whether they should have associated relocation entries. Both the
SPARC 32-bit and 64-bit ELF specifications say that they should have
relocation entries, but the 32-bit SPARC binutils do not generate
them, and now the 64-bit SPARC binutils have stopped generating them
too.
To provide binary compatibility, we will check the first entry, if it
is reserved it should not be of the type JMP_SLOT. If it is JMP_SLOT,
then the 4 reserved entries were not generated and our index is 4
entries too far, so we frob the rela pointer.
kcah
hack gcc-arm32-schedule
mdate 04 May 2000
who is
file lib/libc/stdlib/strtoull.c : 1.3 : 78 : 81
file lib/libc/stdlib/strtouq.c : 1.15 : 73 : 76
pr 9613
descr
strtoull() was returning a wrong result for small numbers with bit 31
set. This is a gcc/arm32 compiler bug in gcc < 2.95.2. Adding
(void)&acc; works around it.
kcah
hack gcc-sparc64-memorysize
mdate 17 Sep 2000
who mrg
port sparc64
file lib/libc/hash/sha1.c : 1.6 : 78 : 129 : 162 : 189
file sys/lib/libkern/sha1.c : 1.6 : 78 : 129 : 162 : 189
file usr.sbin/bind/lib/Makefile : 1.14 : 87 : 91
descr
the normal SHA1Transform() function causes the sparc64 compiler to
use excessive amounts of memory attempting to optimise this function.
using no optimisation allows the function to build. this hack
splits the mathematical functions inside SHA1Transform() into 4
separate functions, which avoids the optimiser explosion.
kcah
hack gcc-sparc64-double-arguments
mdate 18 Sep 2000
who mrg
port sparc64
file xsrc/xc/lib/fonts/Type1/type1.c : 1.2 : 1461 : 1507 : 1702 : 1709
descr
in passing 17 "double" arguments to a function, gcc incorrectly tries
to use a register that doesn't exist, causing an internal error. this
hack changes the way arguments are passed to the function, such that
a pointer to a "double" (really an array) is passed, and the old
arguments are assigned within the function.
kcah
hack gcc-sparc64-gawk
mdate 28 Oct 2000
who mrg
port sparc64
file gnu/usr.bin/gawk/Makefile : 1.11 : 21 : 24
descr
gcc fails to build gawk properly, due to double floating point bugs.
this simple test program will fail to print ``ab'':
BEGIN { f = "abc"; print substr(f, 1, 2); exit }
the work around is simple: use -msoft-quad-float.
kcah
hack gcc-sparc64-libgcc
mdate 01 Dec 2001
who jmc
port sparc64
file gnu/lib/libgcc/Makefile : 1.29 : 24 : 27
descr
gcc fails to do double -> int conversions correctly without
soft-quad-float. Add it in there for the internal conversion
routines. This appears to be more than likely emulations bugs than
compiler bugs as the assembly looks correct on the surface.
kcah
hack gcc-sparc64-iostat-systat
mdate 04 Feb 2001
who mrg
port sparc64
file usr.sbin/iostat/Makefile : 1.17 : 7 : 10
file usr.bin/systat/Makefile : 1.23 : 6 : 9
descr
gcc fails to build iostat properly, due to double floating point bugs.
results will include "Inf" and other garbage.
the work around is simple: use -msoft-quad-float.
kcah
hack gcc-sparc64-nawk
mdate 25 Oct 2001
who martin
port sparc64
file usr.bin/awk/Makefile : 1.3 : 13 : 15
descr
Don't use long double on sparc64.
kcah
hack gcc-sparc64-ntp
mdate 12 Nov 2000
who martin
port sparc64
file usr.sbin/ntp/Makefile.inc : 1.5 : 17 : 19
descr
gcc fails to build ntpd properly, due to double floating point bugs.
Ntpd will fail to decode incoming packets; ntpdc -s will report
a delay, offset and dispersion of 0.0000 for all peers.
the work around is simple: use -msoft-quad-float.
kcah
hack gcc-sparc64-x_dhclient
mdate 27 Dec 2000
who mrg
port sparc64
file distrib/utils/x_dhclient/Makefile : 1.6 : 28 : 30
descr
gcc fails with an ICE while building dhclient's parse.c with -O2
and -Os. the work around is simple: don't use -Os.
kcah
hack lint-no-long-double
mdate 17 Aug 2001
who eeh
port sparc64
file usr.bin/xlint/lint1/param.h: 1.14 :
descr
Don't use long double on sparc64.
kcah
hack netstat ieee1394 address printing.
mdate 14 Nov 2000
who matt
file lib/libc/net/getnameinfo.c : 1.32 : 497 : 503
descr
Because the current implementation of IP over IEEE1394, the
fw device address contains more than just the IEEE1394 EUI-64.
So when printing out IEEE1394 addresses, ignore the extra stuff.
kcah
hack xterm vs. libterm
mdate 01 Aug 2000
who jdc
file xsrc/xc/programs/xterm/main.c : 1.2 : 3609 : 3614
pr 10383
descr
In order to extend the termcap string over 1023 bytes, a ZZ entry was
introduced to point to a memory location containing the full entry.
Without this hack, xterm will export a termcap containing the ZZ
entry, which will then be ignored by libterm. As xterm modifies the
exported termcap, this would cause those modifications to be ignored.
kcah
hack gcc-3-libtelnet
mdate 29 Jan 2002
who thorpej
file lib/libtelnet/Makefile : 1.14 : 14 : 17
descr
GCC 3.x issues a spurious warning when compiling a Duff's Device
with optimization, even though it compiles the file correctly.
GCC PR optimization/5230. kerberos.c contains a Duff's Device
in the checksum routine. Hack is to build libtelnet w/o optimization
if HAVE_GCC3 is set.
kcah
hack gcc-sh3-sed
mdate 23 Apr 2002
who thorpej
file usr.bin/sed/Makefile : 1.9 : 9 : 13
descr
The in-tree GCC 2.95.3-based compiler ICEs when building
with optimization for SuperH. Hack is to biuld with -O0.
kcah
hack gcc-unsigned-compare
cdate 09 Mar 2002
mdate 18 Mar 2002
who bjh21
port arm
file dist/bind/lib/nameser/ns_parse.c : 1.3
file dist/dhcp/minires/ns_parse.c : 1.3
file dist/dhcp/omapip/result.c : 1.2
file dist/dhcp/server/failover.c : 1.3
file gnu/dist/gawk/eval.c : 1.4
file gnu/dist/toolchain/bfd/bfd.c : 1.2
file gnu/dist/toolchain/bfd/format.c : 1.2
file gnu/dist/toolchain/gdb/target.c : 1.2
file sys/kern/vfs_subr.c : 1.172
descr When checking that a potentially-unsigned enum is >= 0, assign it
to an int first. This is necessary to avoid "comparison is always
true" warnings with -fshort-enums. Casting to an int really should
be enough, but turns out not to be.
kcah
hack wi-at-big-endian-bus
cdate 15 Mar 2002
who martin
file dev/ic/wireg.h
descr Add an option to access the underlying bus in big endian byte order
to work around deficiencies in bus_space_{read,write}_* macros.
Those don't allow the implementation of a proper pcmcia bus space
tag.
kcah
hack gcc 2.95.3 -O2 (-fgcse) bug
cdate Sun May 5 18:36:04 UTC 2002
who tsutsui
port macppc
file sys/arch/macppc/dev/adb_direct.c: 1.24 : 1895 : 1896
pr 16678
descr
gcc-2.95.3 does generates wrong code on optimization
by gcc -O2 (-fgcse), and adb_read_date_time() returns
wrong value on cuda system.
A null asm statement has been added to avoid this for workaround.
kcah
hack gcc-vax-libbz2
mdate 27 Jun 2002
who thorpej
port vax
file lib/libbz2/Makefile
descr
libbz2 is mis-compiled with optimization with GCC 2.95.3
on VAX. -O0 works around this problem.
kcah
hack egcs-pc532-ip6_mroute
cdate 09 Jul 2002
who simonb
port pc532
file sys/arch/pc532/conf/Makefile.pc532 : 1.70
file sys/arch/pc532/conf/files.pc532 : 1.47
descr
egcs 1.1.2 gets an "internal error--insn does not satisfy its
constraints" error compiling ip6_mroute.c with -O2 or greater.
-O1 works around this problem.
kcah
hack SuperH SH5 Toolchain Bugs
cdate 11 Jul 2002
who scw
port sh5
file usr.sbin/ndbootd/ndbootd.c : 1.6
file usr.sbin/traceroute/traceroute.c : 1.48
descr
The SuperH SH5 toolchain (2.97-sh5-010522) gets an internal
compiler error when assigning a bit-wise inverted value
under some circumstances.
Work around it by splitting the statement into two.
kcah