binutils-gdb/ld
Nick Alcock fa03171fb4 ld: do not produce one empty output .ctf section for every input .ctf
The trick we use to prevent ld doing as it does for almost all other
sections and copying the input CTF section into the output has recently
broken, causing output to be produced with a valid CTF section followed
by massive numbers of CTF sections, one per .ctf in the input (minus
one, for the one that was filled out by ctf_link).  Their size is being
forcibly set to zero, but they're still present, wasting space and
looking ridiculous.

This is not right:

ld/ld-new  :
section                     size      addr
.interp                       28   4194984
[...]
.bss                       21840   6788544
.comment                      92         0
.ctf                       87242         0
.ctf                           0         0
.ctf                           0         0
[snip 131 more empty sections]
.gnu.build.attributes       7704   6818576
.debug_aranges              6592         0
.debug_info              4488859         0
.debug_abbrev             150099         0
.debug_line               796759         0
.debug_str                237926         0
.debug_loc               2247302         0
.debug_ranges             237920         0
Total                   10865285

The fix is to exclude these unwanted input sections from being present
in the output.  We tried this before and it broke things, because if you
exclude all the .ctf sections there isn't going to be one in the output
so there is nowhere to put the deduplicated CTF. The solution to that is
really simple: set SEC_EXCLUDE on *all but one* CTF section.  We don't
care which one (they're all the same once their size has been zeroed),
so just pick the first we see.

ld/
	* ldlang.c (ldlang_open_ctf): Set SEC_EXCLUDE on all but the
	first input .ctf section.
2020-07-22 18:05:32 +01:00
..
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 ld, testsuite: only run CTF tests when ld and GCC support CTF 2020-07-22 18:05:32 +01:00
.gitignore
aclocal.m4 binutils, ld: work with --disable-libctf 2020-06-26 15:56:39 +01:00
ChangeLog ld: do not produce one empty output .ctf section for every input .ctf 2020-07-22 18:05:32 +01:00
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 ld, testsuite: only run CTF tests when ld and GCC support CTF 2020-07-22 18:05:32 +01:00
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 PR 22843: ld, gold: Add --dependency-file option. 2020-06-23 12:01:24 -07:00
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 ld: do not produce one empty output .ctf section for every input .ctf 2020-07-22 18:05:32 +01:00
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 ld, testsuite: only run CTF tests when ld and GCC support CTF 2020-07-22 18:05:32 +01:00
Makefile.in ld, testsuite: only run CTF tests when ld and GCC support CTF 2020-07-22 18:05:32 +01:00
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
  insulate the linker itself from the format of object files.

* The linker supports a number of different object file
  formats.  It can even handle multiple formats at once:
  Read two input formats and write a third.

* 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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