binutils-gdb/ld
Jan Beulich f2d4ba38f5 gas/ELF: don't accumulate .type settings
Recently a patch was submitted for a Xen Project test harness binary to
override the compiler specified @object to @func (see [1]). In a reply I
suggested we shouldn't make ourselves dependent on currently unspecified
behavior of gas here: It accumulates all requests, and then
bfd/elf.c:swap_out_syms(), in an apparently ad hoc manner, prioritizes
certain flags over others.

Make the behavior predictable: Generally the last .type is what counts.
Exceptions are directives which set multiple bits (TLS, IFUNC, and
UNIQUE): Subsequent directives requesting just the more generic bit
(i.e. FUNC following IFUNC) won't clear the more specific one.  Warn
about incompatible changes, except from/to STT_NOTYPE.

Also add a new target hook, which hppa wants to use right away afaict.

In the course of adding the warning I ran into two ld testsuite
failures.  I can only assume that it was a copy-and-paste mistake that
lead to the same symbol having its type set twice.

[1] https://lists.xenproject.org/archives/html/xen-devel/2019-05/msg01980.html
2019-07-04 10:35:47 +02:00
..
emulparams s12z genelf.em 2019-05-30 01:01:42 +09:30
emultempl Fix a bug recently introduced to the linker where it would complain about a section being larger than a file, even if the section was artificial. 2019-07-02 14:14:13 +01:00
po Regen POTFILES for bpf 2019-05-24 23:15:07 +09:30
scripttempl Use the correct names for the init and fini array start symbols in the default Pru linker script. 2019-05-09 10:26:11 +01:00
testsuite gas/ELF: don't accumulate .type settings 2019-07-04 10:35:47 +02:00
.gitignore
aclocal.m4
ChangeLog gas/ELF: don't accumulate .type settings 2019-07-04 10:35:47 +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-9197
ChangeLog-9899
config.in
configure Regenerate with approved autotools version 2019-06-14 10:30:35 +09:30
configure.ac Automatic makefile dependencies for generated ld/e*.c 2019-04-13 12:13:22 +09:30
configure.host
configure.tgt ld: add support for eBPF 2019-05-23 19:34:15 +02:00
deffile.h
deffilep.y
dep-in.sed
elf-hints-local.h
fdl.texi
gen-doc.texi
genscrba.sh Automatic makefile dependencies for generated ld/e*.c 2019-04-13 12:13:22 +09:30
genscripts.sh Fix automatic makefile dependencies for generated ld/e*.c 2019-04-23 17:02:44 +09:30
h8-doc.texi
ld.h ld: Add --no-print-map-discarded option 2019-04-11 10:16:31 -07:00
ld.texi LD/doc: Clarify `-rpath' option's semantics WRT link-time dependencies 2019-06-07 19:25:21 +01:00
ldbuildid.c Fix compile time warning when building the linker in a MinGw32 environment using gcc 8. 2019-05-08 16:54:16 +01:00
ldbuildid.h
ldcref.c
ldctor.c
ldctor.h
ldemul.c
ldemul.h
ldexp.c
ldexp.h
ldfile.c Re: Have the linker report an error if the same script is used twice 2019-05-23 10:38:45 +09:30
ldfile.h Have the linker report an error if the same script is used twice. 2019-05-22 15:58:57 +01:00
ldgram.y
ldint.texi
ldlang.c ld: Add --no-print-map-discarded option 2019-04-11 10:16:31 -07:00
ldlang.h
ldlex-wrapper.c
ldlex.h ld: Add --no-print-map-discarded option 2019-04-11 10:16:31 -07:00
ldlex.l PR24411, Division is not accepted in MEMORY length expression 2019-04-03 13:01:49 +10:30
ldmain.c Have the linker report an error if the same script is used twice. 2019-05-22 15:58:57 +01:00
ldmain.h
ldmisc.c
ldmisc.h
ldver.c
ldver.h
ldwrite.c
ldwrite.h
lexsup.c Have the linker report an error if the same script is used twice. 2019-05-22 15:58:57 +01:00
MAINTAINERS
Makefile.am ld: add support for eBPF 2019-05-23 19:34:15 +02:00
Makefile.in Regenerate with approved autotools version 2019-06-14 10:30:35 +09:30
mri.c
mri.h
NEWS [LD, AArch64] Move ELF options behind -z 2019-06-06 12:21:14 +01:00
pe-dll.c
pe-dll.h
pep-dll.c
pep-dll.h
plugin.c ld/plugins: avoid shadowing a C library symbol 2019-06-25 12:02:23 +02:00
plugin.h
README
stamp-h.in
sysdep.h
testplug2.c
testplug3.c
testplug4.c
testplug.c
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.

Copyright (C) 2012-2019 Free Software Foundation, Inc.

Copying and distribution of this file, with or without modification,
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