binutils-gdb/ld
Indu Bhagat cf0e0a0ba9 bfd: linker: merge .sframe sections
The linker merges all the input .sframe sections.  When merging, the
linker verifies that all the input .sframe sections have the same
abi/arch.

The linker uses libsframe library to perform key actions on the
.sframe sections - decode, read, and create output data.  This
implies buildsystem changes to make and install libsframe before
libbfd.

The linker places the output .sframe section in a new segment of its
own: PT_GNU_SFRAME.  A new segment is not added, however, if the
generated .sframe section is empty.

When a section is discarded from the final link, the corresponding
entries in the .sframe section for those functions are also deleted.

The linker sorts the SFrame FDEs on start address by default and sets
the SFRAME_F_FDE_SORTED flag in the .sframe section.

This patch also adds support for generation of SFrame unwind
information for the .plt* sections on x86_64.  SFrame unwind info is
generated for IBT enabled PLT, lazy/non-lazy PLT.

The existing linker option --no-ld-generated-unwind-info has been
adapted to include the control of whether .sframe unwind information
will be generated for the linker generated sections like PLT.

Changes to the linker script have been made as necessary.

ChangeLog:

	* Makefile.def: Add install dependency on libsframe for libbfd.
	* Makefile.in: Regenerated.
	* bfd/Makefile.am: Add elf-sframe.c
	* bfd/Makefile.in: Regenerated.
	* bfd/bfd-in2.h (SEC_INFO_TYPE_SFRAME): Regenerated.
	* bfd/configure: Regenerate.
	* bfd/configure.ac: Add elf-sframe.lo.
	* bfd/elf-bfd.h (struct sframe_func_bfdinfo): New struct.
	(struct sframe_dec_info): Likewise.
	(struct sframe_enc_info): Likewise.
	(struct elf_link_hash_table): New member for encoded .sframe
	object.
	(struct output_elf_obj_tdata): New member.
	(elf_sframe): New access macro.
	(_bfd_elf_set_section_sframe): New declaration.
	* bfd/elf.c (get_segment_type): Handle new segment
	PT_GNU_SFRAME.
	(bfd_section_from_phdr): Likewise.
	(get_program_header_size): Likewise.
	(_bfd_elf_map_sections_to_segments): Likewise.
	* bfd/elf64-x86-64.c (elf_x86_64_link_setup_gnu_properties): Add
	contents to the .sframe sections or .plt* entries.
	* bfd/elflink.c (elf_section_ignore_discarded_relocs): Handle
	SEC_INFO_TYPE_SFRAME.
	(_bfd_elf_default_action_discarded): Handle .sframe section.
	(elf_link_input_bfd): Merge .sframe section.
	(bfd_elf_final_link): Write the output .sframe section.
	(bfd_elf_discard_info): Handle discarding .sframe section.
	* bfd/elfxx-x86.c (_bfd_x86_elf_size_dynamic_sections): Create
	.sframe section for .plt and .plt.sec.
	(_bfd_x86_elf_finish_dynamic_sections): Handle .sframe from
	.plt* sections.
	* bfd/elfxx-x86.h (PLT_SFRAME_FDE_START_OFFSET): New
	definition.
	(SFRAME_PLT0_MAX_NUM_FRES): Likewise.
	(SFRAME_PLTN_MAX_NUM_FRES): Likewise.
	(struct elf_x86_sframe_plt): New structure.
	(struct elf_x86_link_hash_table): New member.
	(struct elf_x86_init_table): New members for .sframe
	creation.
	* bfd/section.c: Add new definition SEC_INFO_TYPE_SFRAME.
	* binutils/readelf.c (get_segment_type): Handle new segment
	PT_GNU_SFRAME.
	* ld/ld.texi: Update documentation for
	--no-ld-generated-unwind-info.
	* ld/scripttempl/elf.sc: Support .sframe sections.
	* ld/Makefile.am (TESTSFRAMELIB): Use it.
	(check-DEJAGNU): Likewise.
	* ld/Makefile.in: Regenerated.
	* ld/configure.ac (TESTSFRAMELIB): Set to the .so or .a like TESTBFDLIB.
	* ld/configure: Regenerated.
	* bfd/elf-sframe.c: New file.

include/ChangeLog:

	* elf/common.h (PT_GNU_SFRAME): New definition.
	* elf/internal.h (struct elf_segment_map): Handle new segment
	type PT_GNU_SFRAME.

ld/testsuite/ChangeLog:

	* ld/testsuite/ld-bootstrap/bootstrap.exp: Add SFRAMELIB.
	* ld/testsuite/ld-aarch64/aarch64-elf.exp: Add new test
	  sframe-simple-1.
	* ld/testsuite/ld-aarch64/sframe-bar.s: New file.
	* ld/testsuite/ld-aarch64/sframe-foo.s: Likewise.
	* ld/testsuite/ld-aarch64/sframe-simple-1.d: Likewise.
	* ld/testsuite/ld-sframe/sframe-empty.d: New test.
	* ld/testsuite/ld-sframe/sframe-empty.s: New file.
	* ld/testsuite/ld-sframe/sframe.exp: New testsuite.
	* ld/testsuite/ld-x86-64/sframe-bar.s: New file.
	* ld/testsuite/ld-x86-64/sframe-foo.s: Likewise.
	* ld/testsuite/ld-x86-64/sframe-simple-1.d: Likewise.
	* ld/testsuite/ld-x86-64/sframe-plt-1.d: Likewise.
	* ld/testsuite/ld-x86-64/sframe-simple-1.d: Likewise.
	* ld/testsuite/ld-x86-64/x86-64.exp: Add new tests -
	  sframe-simple-1, sframe-plt-1.
	* ld/testsuite/lib/ld-lib.exp: Add new proc to check if
	  assembler supports SFrame section.
	* ld/testsuite/ld-sframe/discard.d: New file.
	* ld/testsuite/ld-sframe/discard.ld: Likewise.
	* ld/testsuite/ld-sframe/discard.s: Likewise.
2022-11-15 15:49:47 -08:00
..
emulparams aarch64-pe support for LD, GAS and BFD 2022-10-19 10:57:12 +02:00
emultempl ld: Add minimal pdb generation 2022-10-20 15:22:37 +10:30
po Updated Romainain translation for the binutils sub-directory and Swedish translations for the ld and opcodes sub-directories. 2022-10-31 14:42:47 +00:00
scripttempl bfd: linker: merge .sframe sections 2022-11-15 15:49:47 -08:00
testsuite bfd: linker: merge .sframe sections 2022-11-15 15:49:47 -08:00
.gitignore
aclocal.m4 binutils, gdb: support zstd compressed debug sections 2022-09-26 19:50:13 -07:00
ChangeLog V850 Linker: do not complain about RWX segments. 2022-11-03 16:27:31 +00:00
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 rotation 2019-01-01 21:25:40 +10:30
ChangeLog-2019 ChangeLog rotation 2020-01-01 18:12:08 +10:30
ChangeLog-2020 ChangeLog rotation 2021-01-01 10:31:02 +10:30
ChangeLog-9197
ChangeLog-9899 PR27116, Spelling errors found by Debian style checker 2021-01-01 14:36:35 +10:30
config.in add --enable-default-compressed-debug-sections-algorithm configure option 2022-10-11 14:15:04 +02:00
configure bfd: linker: merge .sframe sections 2022-11-15 15:49:47 -08:00
configure.ac bfd: linker: merge .sframe sections 2022-11-15 15:49:47 -08:00
configure.host Update year range in copyright notice of binutils files 2022-01-02 12:04:28 +10:30
configure.tgt V850 Linker: do not complain about RWX segments. 2022-11-03 16:27:31 +00:00
deffile.h ld: pe: Apply review suggestions on the existing exports/imports arrays 2022-09-12 11:07:35 +03:00
deffilep.y ld: pe: Apply review suggestions on the existing exports/imports arrays 2022-09-12 11:07:35 +03:00
dep-in.sed
elf-hints-local.h Remove bfd_stdint.h 2021-03-31 10:49:23 +10:30
fdl.texi
gen-doc.texi Update year range in copyright notice of binutils files 2022-01-02 12:04:28 +10:30
genscrba.sh Automatic makefile dependencies for generated ld/e*.c 2019-04-13 12:13:22 +09:30
genscripts.sh Update year range in copyright notice of binutils files 2022-01-02 12:04:28 +10:30
h8-doc.texi Update year range in copyright notice of binutils files 2022-01-02 12:04:28 +10:30
ld.h Add a -w option to the linker to suppress warning and error messages. 2022-10-21 12:20:09 +01:00
ld.texi bfd: linker: merge .sframe sections 2022-11-15 15:49:47 -08:00
ldbuildid.c Update year range in copyright notice of binutils files 2022-01-02 12:04:28 +10:30
ldbuildid.h Update year range in copyright notice of binutils files 2022-01-02 12:04:28 +10:30
ldcref.c Update year range in copyright notice of binutils files 2022-01-02 12:04:28 +10:30
ldctor.c Re: Get rid of fprintf_vma and sprintf_vma 2022-08-04 12:00:36 +09:30
ldctor.h Update year range in copyright notice of binutils files 2022-01-02 12:04:28 +10:30
ldelf.c ld: add --package-metadata 2022-05-26 12:56:12 +09:30
ldelf.h ld: add --package-metadata 2022-05-26 12:56:12 +09:30
ldelfgen.c elf: Pass need_layout to _bfd_elf_map_sections_to_segments 2022-01-12 05:15:18 -08:00
ldelfgen.h Update year range in copyright notice of binutils files 2022-01-02 12:04:28 +10:30
ldemul.c ld: Add a before_plugin_all_symbols_read hook 2022-03-09 18:23:43 -08:00
ldemul.h ld: Add a before_plugin_all_symbols_read hook 2022-03-09 18:23:43 -08:00
ldexp.c -z relro relaxation and ld script SIZEOF 2022-06-27 12:28:59 +09:30
ldexp.h PR28824, relro security issues 2022-02-13 14:00:56 +10:30
ldfile.c Update year range in copyright notice of binutils files 2022-01-02 12:04:28 +10:30
ldfile.h Update year range in copyright notice of binutils files 2022-01-02 12:04:28 +10:30
ldgram.y ld: Support customized output section type 2022-02-16 17:41:23 +00:00
ldint.texi Update year range in copyright notice of binutils files 2022-01-02 12:04:28 +10:30
ldlang.c Don't use BFD_VMA_FMT in binutils 2022-08-04 12:22:39 +09:30
ldlang.h Fix a conflict between the linker's need to rename some PE format input libraries and the BFD library's file caching mechanism. 2022-08-03 13:31:57 +01:00
ldlex-wrapper.c Update year range in copyright notice of binutils files 2022-01-02 12:04:28 +10:30
ldlex.h Add a -w option to the linker to suppress warning and error messages. 2022-10-21 12:20:09 +01:00
ldlex.l ld: Support customized output section type 2022-02-16 17:41:23 +00:00
ldmain.c add --enable-default-compressed-debug-sections-algorithm configure option 2022-10-11 14:15:04 +02:00
ldmain.h Update year range in copyright notice of binutils files 2022-01-02 12:04:28 +10:30
ldmisc.c Add a -w option to the linker to suppress warning and error messages. 2022-10-21 12:20:09 +01:00
ldmisc.h Re: Get rid of fprintf_vma and sprintf_vma 2022-08-04 12:00:36 +09:30
ldver.c Update year range in copyright notice of binutils files 2022-01-02 12:04:28 +10:30
ldver.h Update year range in copyright notice of binutils files 2022-01-02 12:04:28 +10:30
ldwrite.c Update year range in copyright notice of binutils files 2022-01-02 12:04:28 +10:30
ldwrite.h Update year range in copyright notice of binutils files 2022-01-02 12:04:28 +10:30
lexsup.c Add a -w option to the linker to suppress warning and error messages. 2022-10-21 12:20:09 +01:00
libdep_plugin.c Fix potential arithmetic overflow in the linker's plugin handling code. 2022-05-03 11:41:45 +01:00
MAINTAINERS Update year range in copyright notice of binutils files 2022-01-02 12:04:28 +10:30
Makefile.am bfd: linker: merge .sframe sections 2022-11-15 15:49:47 -08:00
Makefile.in bfd: linker: merge .sframe sections 2022-11-15 15:49:47 -08:00
mri.c ld: Support customized output section type 2022-02-16 17:41:23 +00:00
mri.h Update year range in copyright notice of binutils files 2022-01-02 12:04:28 +10:30
NEWS Add a -w option to the linker to suppress warning and error messages. 2022-10-21 12:20:09 +01:00
pdb.c ld: Add module information substream to PDB files 2022-11-10 04:50:43 +00:00
pdb.h ld: Add module information substream to PDB files 2022-11-10 04:50:43 +00:00
pe-dll.c aarch64-pe support for LD, GAS and BFD 2022-10-19 10:57:12 +02:00
pe-dll.h Update year range in copyright notice of binutils files 2022-01-02 12:04:28 +10:30
pep-dll-aarch64.c aarch64-pe support for LD, GAS and BFD 2022-10-19 10:57:12 +02:00
pep-dll-x86_64.c aarch64-pe support for LD, GAS and BFD 2022-10-19 10:57:12 +02:00
pep-dll.c aarch64-pe support for LD, GAS and BFD 2022-10-19 10:57:12 +02:00
pep-dll.h Update year range in copyright notice of binutils files 2022-01-02 12:04:28 +10:30
plugin.c PR12265, Compiling ld/ fails on Solaris 8 2022-08-26 18:56:01 +09:30
plugin.h Update year range in copyright notice of binutils files 2022-01-02 12:04:28 +10:30
README Update year range in copyright notice of binutils files 2022-01-02 12:04:28 +10:30
sysdep.h PR12265, Compiling ld/ fails on Solaris 8 2022-08-26 18:56:01 +09:30
testplug2.c Update year range in copyright notice of binutils files 2022-01-02 12:04:28 +10:30
testplug3.c Update year range in copyright notice of binutils files 2022-01-02 12:04:28 +10:30
testplug4.c Update year range in copyright notice of binutils files 2022-01-02 12:04:28 +10:30
testplug.c Update year range in copyright notice of binutils files 2022-01-02 12:04:28 +10:30
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.

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Copying and distribution of this file, with or without modification,
are permitted in any medium without royalty provided the copyright
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