b7d0721677
As shown in https://sourceware.org/bugzilla/show_bug.cgi?id=25490 --gc-sections will silently remove __patchable_function_entries section and generate corrupt result. This patch adds the section flag 'o' to .section directive: .section __patchable_function_entries,"awo",@progbits,foo .section __patchable_function_entries,"awoG",@progbits,foo,foo,comdat .section __patchable_function_entries,"awo",@progbits,bar,unique,4 .section __patchable_function_entries,"awoG",@progbits,foo,foo,comdat,unique,1 which specifies the symbol name which the section references. Assmebler will set its elf_linked_to_section to a local section where the symbol is defined. Linker is updated to call mark_hook if gc_mark of any of its linked-to sections is set after all sections, except for backend specific ones, have been garbage collected. bfd/ PR gas/25381 * bfd-in2.h: Regenerated. * elflink.c (_bfd_elf_gc_mark_extra_sections): Call mark_hook on section if gc_mark of any of its linked-to sections is set and don't set gc_mark again. * section.c (asection): Add linked_to_symbol_name to map_head union. gas/ PR gas/25381 * config/obj-elf.c (get_section): Also check linked_to_symbol_name. (obj_elf_change_section): Also set map_head.linked_to_symbol_name. (obj_elf_parse_section_letters): Handle the 'o' flag. (build_group_lists): Renamed to ... (build_additional_section_info): This. Set elf_linked_to_section from map_head.linked_to_symbol_name. (elf_adjust_symtab): Updated. * config/obj-elf.h (elf_section_match): Add linked_to_symbol_name. * doc/as.texi: Document the 'o' flag. * testsuite/gas/elf/elf.exp: Run PR gas/25381 tests. * testsuite/gas/elf/section18.d: New file. * testsuite/gas/elf/section18.s: Likewise. * testsuite/gas/elf/section19.d: Likewise. * testsuite/gas/elf/section19.s: Likewise. * testsuite/gas/elf/section20.d: Likewise. * testsuite/gas/elf/section20.s: Likewise. * testsuite/gas/elf/section21.d: Likewise. * testsuite/gas/elf/section21.l: Likewise. * testsuite/gas/elf/section21.s: Likewise. ld/ PR ld/24526 PR ld/25021 PR ld/25490 * testsuite/ld-elf/elf.exp: Run PR ld/25490 tests. * testsuite/ld-elf/pr24526.d: New file. * testsuite/ld-elf/pr24526.s: Likewise. * testsuite/ld-elf/pr25021.d: Likewise. * testsuite/ld-elf/pr25021.s: Likewise. * testsuite/ld-elf/pr25490-2-16.rd: Likewise. * testsuite/ld-elf/pr25490-2-32.rd: Likewise. * testsuite/ld-elf/pr25490-2-64.rd: Likewise. * testsuite/ld-elf/pr25490-2.s: Likewise. * testsuite/ld-elf/pr25490-3-16.rd: Likewise. * testsuite/ld-elf/pr25490-3-32.rd: Likewise. * testsuite/ld-elf/pr25490-3-64.rd: Likewise. * testsuite/ld-elf/pr25490-3.s: Likewise. * testsuite/ld-elf/pr25490-4-16.rd: Likewise. * testsuite/ld-elf/pr25490-4-32.rd: Likewise. * testsuite/ld-elf/pr25490-4-64.rd: Likewise. * testsuite/ld-elf/pr25490-4.s: Likewise. * testsuite/ld-elf/pr25490-5-16.rd: Likewise. * testsuite/ld-elf/pr25490-5-32.rd: Likewise. * testsuite/ld-elf/pr25490-5-64.rd: Likewise. * testsuite/ld-elf/pr25490-5.s: Likewise. * testsuite/ld-elf/pr25490-6-16.rd: Likewise. * testsuite/ld-elf/pr25490-6-32.rd: Likewise. * testsuite/ld-elf/pr25490-6-64.rd: Likewise. * testsuite/ld-elf/pr25490-6.s: Likewise.
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.