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f02cb05882
See https://sourceware.org/ml/binutils/2016-07/msg00091.html This patch stop --gc-sections elf_gc_sweep_symbol localizing symbols that ought to remain global. The difficulty with always descending into output section statements is that symbols defined by the script in such statements don't have a bfd section when lang_do_assignments runs early in the link process. There are two approaches to curing this problem. Either we can create the bfd section early, or we can use a special section. This patch takes the latter approach and uses bfd_und_section. (Creating bfd sections early results in changed output section order, and thus lots of testsuite failures. You can't create all output sections early to ensure proper ordering as KEEP then stops empty sections from being stripped.) The wrinkle with this approach is that some code that runs at gc-sections time needs to be made aware of the odd defined symbols using bfd_und_section. bfd/ * elf64-x86-64.c (elf_x86_64_convert_load_reloc): Handle symbols defined temporarily with bfd_und_section. * elflink.c (_bfd_elf_gc_keep): Don't set SEC_KEEP for bfd_und_section. * elfxx-mips.c (mips_elf_local_pic_function_p): Exclude defined symbols with bfd_und_section. ld/ * ldlang.c (lang_do_assignments_1): Descend into output section statements that do not yet have bfd sections. Set symbol section temporarily for symbols defined in such statements to the undefined section. Don't error on data or reloc statements until final phase. * ldexp.c (exp_fold_tree_1 <etree_assign>): Handle bfd_und_section in expld.section. * testsuite/ld-mmix/bpo-10.d: Adjust. * testsuite/ld-mmix/bpo-11.d: Adjust. |
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| .. | ||
| emulparams | ||
| emultempl | ||
| po | ||
| scripttempl | ||
| testsuite | ||
| .gitignore | ||
| aclocal.m4 | ||
| ChangeLog | ||
| 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-9197 | ||
| ChangeLog-9899 | ||
| config.in | ||
| configure | ||
| configure.ac | ||
| configure.host | ||
| configure.tgt | ||
| 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.texinfo | ||
| ldbuildid.c | ||
| ldbuildid.h | ||
| ldcref.c | ||
| ldctor.c | ||
| ldctor.h | ||
| ldemul.c | ||
| ldemul.h | ||
| ldexp.c | ||
| ldexp.h | ||
| ldfile.c | ||
| ldfile.h | ||
| ldgram.y | ||
| ldint.texinfo | ||
| ldlang.c | ||
| ldlang.h | ||
| ldlex-wrapper.c | ||
| ldlex.h | ||
| ldlex.l | ||
| ldmain.c | ||
| ldmain.h | ||
| ldmisc.c | ||
| ldmisc.h | ||
| ldver.c | ||
| ldver.h | ||
| ldwrite.c | ||
| ldwrite.h | ||
| lexsup.c | ||
| MAINTAINERS | ||
| Makefile.am | ||
| Makefile.in | ||
| mri.c | ||
| mri.h | ||
| NEWS | ||
| pe-dll.c | ||
| pe-dll.h | ||
| pep-dll.c | ||
| pep-dll.h | ||
| plugin.c | ||
| plugin.h | ||
| README | ||
| stamp-h.in | ||
| sysdep.h | ||
| testplug2.c | ||
| testplug3.c | ||
| testplug4.c | ||
| testplug.c | ||
| TODO | ||
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.texinfo), as well as the
beginnings of an internals manual (ldint.texinfo).
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.texinfo 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.
Copyright (C) 2012-2016 Free Software Foundation, Inc.
Copying and distribution of this file, with or without modification,
are permitted in any medium without royalty provided the copyright
notice and this notice are preserved.