binutils-gdb/ld
Rainer Orth c8693053f8 Unify Solaris procfs and largefile handling
GDB currently doesn't build on 32-bit Solaris:

* On Solaris 11.4/x86:

In file included from /usr/include/sys/procfs.h:26,
                 from /vol/src/gnu/gdb/hg/master/dist/gdb/i386-sol2-nat.c:24:
/usr/include/sys/old_procfs.h:31:2: error: #error "Cannot use procfs in the large file compilation environment"
 #error "Cannot use procfs in the large file compilation environment"
  ^~~~~

* On Solaris 11.3/x86 there are several more instances of this.

The interaction between procfs and large-file support historically has
been a royal mess on Solaris:

* There are two versions of the procfs interface:

** The old ioctl-based /proc, deprecated and not used any longer in
   either gdb or binutils.

** The `new' (introduced in Solaris 2.6, 1997) structured /proc.

* There are two headers one can possibly include:

** <procfs.h> which only provides the structured /proc, definining
   _STRUCTURED_PROC=1 and then including ...

** <sys/procfs.h> which defaults to _STRUCTURED_PROC=0, the ioctl-based
   /proc, but provides structured /proc if _STRUCTURED_PROC == 1.

* procfs and the large-file environment didn't go well together:

** Until Solaris 11.3, <sys/procfs.h> would always #error in 32-bit
   compilations when the large-file environment was active
   (_FILE_OFFSET_BITS == 64).

** In both Solaris 11.4 and Illumos, this restriction was lifted for
   structured /proc.

So one has to be careful always to define _STRUCTURED_PROC=1 when
testing for or using <sys/procfs.h> on Solaris.  As the errors above
show, this isn't always the case in binutils-gdb right now.

Also one may need to disable large-file support for 32-bit compilations
on Solaris.  config/largefile.m4 meant to do this by wrapping the
AC_SYS_LARGEFILE autoconf macro with appropriate checks, yielding
ACX_LARGEFILE.  Unfortunately the macro doesn't always succeed because
it neglects the _STRUCTURED_PROC part.

To make things even worse, since GCC 9 g++ predefines
_FILE_OFFSET_BITS=64 on Solaris.  So even if largefile.m4 deciced not to
enable large-file support, this has no effect, breaking the gdb build.

This patch addresses all this as follows:

* All tests for the <sys/procfs.h> header are made with
  _STRUCTURED_PROC=1, the definition going into the various config.h
  files instead of having to make them (and sometimes failing) in the
  affected sources.

* To cope with the g++ predefine of _FILE_OFFSET_BITS=64,
  -U_FILE_OFFSET_BITS is added to various *_CPPFLAGS variables.  It had
  been far easier to have just

  #undef _FILE_OFFSET_BITS

  in config.h, but unfortunately such a construct in config.in is
  commented by config.status irrespective of indentation and whitespace
  if large-file support is disabled.  I found no way around this and
  putting the #undef in several global headers for bfd, binutils, ld,
  and gdb seemed way more invasive.

* Last, the applicability check in largefile.m4 was modified only to
  disable largefile support if really needed.  To do so, it checks if
  <sys/procfs.h> compiles with _FILE_OFFSET_BITS=64 defined.  If it
  doesn't, the disabling only happens if gdb exists in-tree and isn't
  disabled, otherwise (building binutils from a tarball), there's no
  conflict.

  What initially confused me was the check for $plugins here, which
  originally caused the disabling not to take place.  Since AC_PLUGINGS
  does enable plugin support if <dlfcn.h> exists (which it does on
  Solaris), the disabling never happened.

  I could find no explanation why the linker plugin needs large-file
  support but thought it would be enough if gld and GCC's lto-plugin
  agreed on the _FILE_OFFSET_BITS value.  Unfortunately, that's not
  enough: lto-plugin uses the simple-object interface from libiberty,
  which includes off_t arguments.  So to fully disable large-file
  support would mean also disabling it in libiberty and its users: gcc
  and libstdc++-v3.  This seems highly undesirable, so I decided to
  disable the linker plugin instead if large-file support won't work.

The patch allows binutils+gdb to build on i386-pc-solaris2.11 (both
Solaris 11.3 and 11.4, using GCC 9.3.0 which is the worst case due to
predefined _FILE_OFFSET_BITS=64).  Also regtested on
amd64-pc-solaris2.11 (again on Solaris 11.3 and 11.4),
x86_64-pc-linux-gnu and i686-pc-linux-gnu.

	config:
	* largefile.m4 (ACX_LARGEFILE) <sparc-*-solaris*|i?86-*-solaris*>:
	Check for <sys/procfs.h> incompatilibity with large-file support
	on Solaris.
	Only disable large-file support and perhaps plugins if needed.
	Set, substitute LARGEFILE_CPPFLAGS if so.

	bfd:
	* bfd.m4 (BFD_SYS_PROCFS_H): New macro.
	(BFD_HAVE_SYS_PROCFS_TYPE): Require BFD_SYS_PROCFS_H.
	Don't define _STRUCTURED_PROC.
	(BFD_HAVE_SYS_PROCFS_TYPE_MEMBER): Likewise.
	* elf.c [HAVE_SYS_PROCFS_H] (_STRUCTURED_PROC): Don't define.
	* configure.ac: Use BFD_SYS_PROCFS_H to check for <sys/procfs.h>.
	* configure, config.in: Regenerate.
	* Makefile.am (AM_CPPFLAGS): Add LARGEFILE_CPPFLAGS.
	* Makefile.in, doc/Makefile.in: Regenerate.

	binutils:
	* Makefile.am (AM_CPPFLAGS): Add LARGEFILE_CPPFLAGS.
	* Makefile.in, doc/Makefile.in: Regenerate.
	* configure: Regenerate.

	gas:
	* Makefile.am (AM_CPPFLAGS): Add LARGEFILE_CPPFLAGS.
	* Makefile.in, doc/Makefile.in: Regenerate.
	* configure: Regenerate.

	gdb:
	* proc-api.c (_STRUCTURED_PROC): Don't define.
	* proc-events.c: Likewise.
	* proc-flags.c: Likewise.
	* proc-why.c: Likewise.
	* procfs.c: Likewise.

	* Makefile.in (INTERNAL_CPPFLAGS): Add LARGEFILE_CPPFLAGS.
	* configure, config.in: Regenerate.

	gdbserver:
	* configure, config.in: Regenerate.

	gdbsupport:
	* Makefile.am (AM_CPPFLAGS): Add LARGEFILE_CPPFLAGS.
	* common.m4 (GDB_AC_COMMON): Use BFD_SYS_PROCFS_H to check for
	<sys/procfs.h>.
	* Makefile.in: Regenerate.
	* configure, config.in: Regenerate.

	gnulib:
	* configure.ac: Run ACX_LARGEFILE before gl_EARLY.
	* configure: Regenerate.

	gprof:
	* Makefile.am (AM_CPPFLAGS): Add LARGEFILE_CPPFLAGS.
	* Makefile.in: Regenerate.
	* configure: Regenerate.

	ld:
	* Makefile.am (AM_CPPFLAGS): Add LARGEFILE_CPPFLAGS.
	* Makefile.in: Regenerate.
	* configure: Regenerate.
2020-07-30 15:41:50 +02:00
..
emulparams ld: optionally emit _etext last, before .data 2020-07-19 06:08:07 +02:00
emultempl Power10 stub selection 2020-07-19 12:27:47 +09:30
po Remove powerpc PE support 2020-07-09 22:58:16 +09:30
scripttempl ld: optionally emit _etext last, before .data 2020-07-19 06:08:07 +02:00
testsuite MIPS: Make the IRIX naming of local section symbols consistent 2020-07-29 20:56:41 +01:00
.gitignore
aclocal.m4 binutils, ld: work with --disable-libctf 2020-06-26 15:56:39 +01:00
ChangeLog Unify Solaris procfs and largefile handling 2020-07-30 15:41:50 +02:00
ChangeLog-0001
ChangeLog-0203
ChangeLog-2004
ChangeLog-2005
ChangeLog-2006
ChangeLog-2007
ChangeLog-2008
ChangeLog-2009
ChangeLog-2010
ChangeLog-2011
ChangeLog-2012
ChangeLog-2013
ChangeLog-2014
ChangeLog-2015
ChangeLog-2016
ChangeLog-2017
ChangeLog-2018
ChangeLog-2019
ChangeLog-9197
ChangeLog-9899
config.in binutils, ld: work with --disable-libctf 2020-06-26 15:56:39 +01:00
configure Unify Solaris procfs and largefile handling 2020-07-30 15:41:50 +02:00
configure.ac ld, testsuite: only run CTF tests when ld and GCC support CTF 2020-07-22 18:05:32 +01:00
configure.host
configure.tgt Remove powerpc PE support 2020-07-09 22:58:16 +09:30
deffile.h
deffilep.y
dep-in.sed
elf-hints-local.h
fdl.texi
gen-doc.texi
genscrba.sh
genscripts.sh
h8-doc.texi
ld.h ld: new options --ctf-variables and --ctf-share-types 2020-07-22 18:03:57 +01:00
ld.texi ld: new options --ctf-variables and --ctf-share-types 2020-07-22 18:03:57 +01:00
ldbuildid.c
ldbuildid.h
ldcref.c
ldctor.c
ldctor.h
ldelf.c Don't assert at ldwrite.c:212 2020-07-29 17:38:01 +09:30
ldelf.h
ldelfgen.c binutils, ld: work with --disable-libctf 2020-06-26 15:56:39 +01:00
ldelfgen.h
ldemul.c
ldemul.h
ldexp.c ld: Set non_ir_ref_regular on source for assignment 2020-06-24 03:56:16 -07:00
ldexp.h
ldfile.c PR 22843: ld, gold: Add --dependency-file option. 2020-06-23 12:01:24 -07:00
ldfile.h
ldgram.y
ldint.texi
ldlang.c More just-syms changes 2020-07-28 13:09:20 +09:30
ldlang.h Do without ld ENABLE_PLUGINS 2020-06-21 22:16:10 +09:30
ldlex-wrapper.c
ldlex.h ld: new options --ctf-variables and --ctf-share-types 2020-07-22 18:03:57 +01:00
ldlex.l
ldmain.c PR 22843: ld, gold: Add --dependency-file option. 2020-06-23 12:01:24 -07:00
ldmain.h PR 22843: ld, gold: Add --dependency-file option. 2020-06-23 12:01:24 -07:00
ldmisc.c
ldmisc.h
ldver.c
ldver.h
ldwrite.c
ldwrite.h
lexsup.c ld: new options --ctf-variables and --ctf-share-types 2020-07-22 18:03:57 +01:00
MAINTAINERS
Makefile.am Unify Solaris procfs and largefile handling 2020-07-30 15:41:50 +02:00
Makefile.in Unify Solaris procfs and largefile handling 2020-07-30 15:41:50 +02:00
mri.c
mri.h
NEWS ld: new options --ctf-variables and --ctf-share-types 2020-07-22 18:03:57 +01:00
pe-dll.c PR 22843: ld, gold: Add --dependency-file option. 2020-06-23 12:01:24 -07:00
pe-dll.h
pep-dll.c
pep-dll.h
plugin.c ld: Properly override the IR definition 2020-07-22 03:49:17 -07:00
plugin.h
README
stamp-h.in
sysdep.h
testplug2.c Do without ld ENABLE_PLUGINS 2020-06-21 22:16:10 +09:30
testplug3.c Do without ld ENABLE_PLUGINS 2020-06-21 22:16:10 +09:30
testplug4.c Do without ld ENABLE_PLUGINS 2020-06-21 22:16:10 +09:30
testplug.c Do without ld ENABLE_PLUGINS 2020-06-21 22:16:10 +09:30
TODO

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		README for LD

This is the GNU linker.  It is distributed with other "binary
utilities" which should be in ../binutils.  See ../binutils/README for
more general notes, including where to send bug reports.

There are many features of the linker:

* The linker uses a Binary File Descriptor library (../bfd)
  that it uses to read and write object files.  This helps
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* The linker supports a number of different object file
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* The linker can be configured for cross-linking.

* The linker supports a control language.

* There is a user manual (ld.texi), as well as the
  beginnings of an internals manual (ldint.texi).

Installation
============

See ../binutils/README.

If you want to make a cross-linker, you may want to specify
a different search path of -lfoo libraries than the default.
You can do this by setting the LIB_PATH variable in ./Makefile
or using the --with-lib-path configure switch.

To build just the linker, make the target all-ld from the top level
directory (one directory above this one).

Porting to a new target
=======================

See the ldint.texi manual.

Reporting bugs etc
===========================

See ../binutils/README.

Known problems
==============

The Solaris linker normally exports all dynamic symbols from an
executable.  The GNU linker does not do this by default.  This is
because the GNU linker tries to present the same interface for all
similar targets (in this case, all native ELF targets).  This does not
matter for normal programs, but it can make a difference for programs
which try to dlopen an executable, such as PERL or Tcl.  You can make
the GNU linker export all dynamic symbols with the -E or
--export-dynamic command line option.

HP/UX 9.01 has a shell bug that causes the linker scripts to be
generated incorrectly.  The symptom of this appears to be "fatal error
- scanner input buffer overflow" error messages.  There are various
workarounds to this:
  * Build and install bash, and build with "make SHELL=bash".
  * Update to a version of HP/UX with a working shell (e.g., 9.05).
  * Replace "(. ${srcdir}/scripttempl/${SCRIPT_NAME}.sc)" in
    genscripts.sh with "sh ${srcdir}..." (no parens) and make sure the
    emulparams script used exports any shell variables it sets.

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