NetBSD/doc/HACKS

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# $NetBSD: HACKS,v 1.9 2003/09/19 16:41:58 martin 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 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 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-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
hack vax Toolchain bug
cdate 28 Mar 2003
who he
port vax
file sys/arch/vax/vax/intvec.S : 1.5
descr
Workaround for PR toolchain/20924. The assembler apparently
tries to range-check byte offsets when it doesn't have
sufficient information to make that decision.
Workaround uses `brw' instead of `brb' instruction.
kcah
hack specific knowledge of colours in curses code
cdate Sun Apr 6 11:05:24 BST 2003
who jdc
port all
file lib/libcurses/color.c : r1.24
descr
Swap red/blue and yellow/cyan colours for COLOR_OTHER.
Fix is to enhance libtermcap to understand terminfo-style % sequences.
See also:
http://mail-index.NetBSD.org/tech-userlevel/2003/04/06/0000.html
kcah
hack SuperH SH5 Toolchain Bugs
cdate 17 May 2003
who scw
port sh5
file lib/libpthread/pthread_lock.c : 1.7
descr
The SuperH SH5 toolchain generates incorrect PIC code when faced
with a symbol which is declared extern, but has local scope due
to being defined within an asm() statement (without being declared
.globl in that statement). Work around it by adding the .globl.
kcah
hack Compensation for differing types of LINUX_USRSTACK and USRSTACK
cdate 21 Aug 2003
who he
file sys/miscfs/procfs/procfs_linux.c : 1.14
descr
Not all ports have LINUX_USRSTACK and/or USRSTACK defined as
literals/constants, but refer to variables of a type which is
not "unsigned long", causing compilation of procfs_linux.c to
fail with "makes integer from pointer without a cast". This
is observed on e.g. the sun3 port. Ideally the "types" for
symbols should be consistent across all ports.
kcah
hack i386 / sparc default debugging type in GCC 3.3.1
cdate 19 Sept 2003
who mrg
file gnu/dist/gcc/gcc/config/{i386,sparc}/netbsd-elf.h
descr
Until i386 & sparc* switch to GDB 5.3, the default debugging
format needs to be stabs not DWARF.
kcah