xref: /src/doc/HACKS

# $NetBSD: HACKS,v 1.23 2003/11/06 00:37:14 he 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	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	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	specific knowledge of colours in curses code
cdate	Sun Apr  6 11:05:24 BST 2003
who	jdc
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	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


port	vax

	hack	gcc 2.95/vax cannot handle __builtin_ffs()
	cdate	Fri Aug 23 21:31:15 CEST 2002
	who	ragge
	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-vax-libbz2
	mdate	27 Jun 2002
	who	thorpej
	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	vax Toolchain bug
	cdate	28 Mar 2003
	who	he
	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	vax gcc 2.95.3 -Wuninitialized workarounds
	cdate	6 Nov 2003
	who	he
	file	sys/dev/bi/if_ni.c : 1.22
	file	sys/arch/vax/vax/ctu.c : 1.20
	descr
		Workaround for gcc 2.95.3 failing to detect that certain
		variables will be initialized; so that this code compiles
		with -Wuninitialized.  Should be reviewed and possibly
		reverted when gcc 3.3.2 is ready for vax.
	kcah


port	sparc64

	hack	binutil-2.11-sparc64-pltrela
	mdate	14 Aug 2001
	who	eeh
	file	libexec/ld.elf_so/arch/sparc64/mdreloc.c
	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


port	arm

	hack	gcc-unsigned-compare
	cdate	09 Mar 2002
	mdate	18 Mar 2002
	who	bjh21
	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	gcc 3.3.x bug
	cdate	Sun Oct 26 01:50:16 UTC 2003
	who	lukem
	file	usr.bin/newsyslog/newsyslog.c
	pr	22986 23002 23217
	descr
		newsyslog fails with
			newsyslog: config line 7: bad flags
		solved when compiled with -fno-gcse-lm
	kcah

	hack	gcc 3.3.2/arm sys/kern/uipc_socket.c
	cdate	Tue Oct 28 18:02:16 GMT 2003
	who	skrll
	file	sys/conf/arm/Makefile.arm : 1.19
	descr
		Performing a build.sh tools on a CATS with NFS mounted 
		obj and src directories results in "panic: receive 1"
		The hack is to compile sys/kern/uipc_socket.c with
		-fno-strict-aliasing
	kcah


port	pc532

	hack	egcs-pc532-ip6_mroute
	cdate	09 Jul 2002
	who	simonb
	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	gcc-pc532-duffs_device
	cdate	Mon Oct 27 07:23:05 UTC 2003
	who	simonb
	file	sys/arch/pc532/conf/Makefile.pc532 : 1.71
	file	sys/arch/pc532/conf/files.pc532 : 1.52
	pr	GCC PR optimization/5230
	descr
		gcc incorrectly gives an "unreachable code at beginning of
		switch statement" for a Duff's device construct in
		arch/pc532/dev/ncr.c.  There is no way to disable just this
		warning, so -Wno-error is turned on for this file.
	kcah


port	sh3

	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


port	sh5

	hack	SuperH SH5 Toolchain Bugs
	cdate	11 Jul 2002
	who	scw
	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	SuperH SH5 Toolchain Bugs
	cdate	17 May 2003
	who	scw
	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


port	sun2

	hack	gcc 3.3.2/mdsetimage
	cdate	Tue Oct 28 18:43:05 EST 2003
	who	fredette
	file	gnu/usr.sbin/mdsetimage/Makefile : 1.15
	descr
		mdsetimage.c causes cc1 to barf for as-yet unknown reasons.
		this hack ues -O0 to avoid the problem.
	kcah

	hack	gcc 3.3.2/installboot/ffs.c
	cdate	Tue Oct 28 18:43:05 EST 2003
	who	fredette
	file	usr.sbin/installboot/Makefile : 1.26
	descr
		ffs.c causes cc1 to barf for as-yet unknown reasons.  this
		hack ues -O0 to avoid the problem.
	kcah


port	sun2, m68k

	hack	gcc 3.3.2/gcc/ra-colorize.c
	cdate	Wed Nov  5 11:03:13 EST 2003
	who	mrg
	file	gnu/usr.bin/gcc/backend/Makefile : 1.11
	descr
		ra-colorize.c causes a whole spew of unreferenced .L* local
		symbols.  using -O0 (or even -O2 reportedly) avoids the problem.
	kcah