forked from Imagelibrary/binutils-gdb
ef1c830f00
The reason behind this patch was noticing that generic ELF targets fail to remove "bar" in the recently committed ld-elf/undefweak-1 test. (Despite that, those targets pass the test due to it being too strict when matching symbols. "bar" gets turned into a local weak defined absolute symbol.) swap_out_syms currently drops local section syms that are defined in discarded sections. Extend that to also drop other symbols in discarded sections too, even global symbols. The linker goes to quite a lot of effort to ensure globals in discarded section take a definition from the kept linkonce or comdat group section. So the global sym change should only affect cases where something is quite wrong about the set of linkonce or comdat group sections. However that change to elf_map_symbols meant we dropped _DYNAMIC_LINK / _DYNAMIC_LINKING for mips, a global absolute symbol given STT_SECTION type for some reason. That problem is fixed by reverting the pr14493 change which is no longer needed due to a) BSF_SECTION_SYM_USED on x86, and b) fixing objcopy to use copy_private_symbol_data. bfd/ PR 14493 * elf.c (ignore_sym): Rename from ignore_section_sym. Return true for any symbol without a section or in a discarded section. Revert pr14493 change. (elf_map_symbols): Tidy. Use ignore_sym on all symbols. (swap_out_syms): Tidy. ld/ * testsuite/ld-elf/undefweak-1.rd: Match any "bar".
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) 2012-2024 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.