This patch delays setting up DT_NEEDED dynamic tags until all object
files and libraries have been opened and their symbols processed,
rather than adding the tags while processing symbols. Tags are
ordered according to the position of the associated library on the
command line and linker scripts. It is still possible with
--as-needed libs that are mentioned more than once for tags to be
ordered according to which mention was needed. For example with
"--as-needed a.so b.so c.so b.so" when b.so is not needed by a.so or
any other prior object file but is needed by c.so, the order of tags
will be "A C B".
bfd/
PR 25593
* elf-bfd.h (struct elf_link_hash_table): Rename "loaded" to
"dyn_loaded".
(bfd_elf_add_dt_needed_tag): Declare.
* elf-strtab.c (_bfd_elf_strtab_restore): Handle NULL buf.
* elflink.c (bfd_elf_add_dt_needed_tag): Make global and rename
from elf_add_dt_needed_tag. Remove soname and doit param.
(elf_link_add_object_symbols): Don't use elf_add_dt_needed_tag
to see whether as-needed lib is already loaded, use dyn_loaded
list instead. When saving and restoring around as-needed lib
handle possibility that dynstr has not been initialised. Don't
add DT_NEEDED tags here. Limit dyn_loaded list to dynamic libs.
Mark libs loaded via DT_NEEDED entries of other libs with
DYN_NO_NEEDED if they should not be mentioned in DT_NEEDED of
the output.
(elf_link_check_versioned_symbol): Remove now unneccesary
DYNAMIC check when traversing dyn_loaded list.
ld/
PR 25593
* ldelf.c (ldelf_try_needed): Add DT_NEEDED lib to input_bfds.
(ldelf_after_open): Save state of input_bfds list before loading
DT_NEEDED libs. Traverse input_bfds list adding DT_NEEDED tags.
Restore input_bfds list.
* testsuite/ld-cris/gotplt1.d: Adjust for changed .dynstr order.
This file contains invisible Unicode characters that are indistinguishable to humans but may be processed differently by a computer. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.
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) 2012-2020 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.
e310298cf3