binutils-gdb/ld
Alan Modra fd161d860f Define various symbols conditionally in shared libraries
The values of symbols in shared libraries like _end, _edata, and
__bss_start are generally not that useful outside of the shared
library.  This patch defines them conditionally with PROVIDE, since a
shared library might need the local value.  An example is glibc ld.so
local access to "_begin", "_etext" and "_end".  (ld.so gains access to
the local values by making the references using hidden visibility.
That makes the definitions hidden too.)

We can't use PROVIDE_HIDDEN in the linker scripts because the shared
library might need the value of the symbol in the executable.  An
example is freebsd libc dynamic access to "_end".

	PR ld/23161
	* emulparams/aarch64cloudabi.sh: PROVIDE __bss_start__, _bss_end__,
	and __end__ in shared libraries.
	* emulparams/aarch64fbsd.sh: Likewise.
	* emulparams/aarch64linux.sh: Likewise.
	* emulparams/aarch64linux32.sh: Likewise.
	* emulparams/armelf_fuchsia.sh: Likewise.
	* emulparams/armelf_linux.sh: Likewise.
	* emulparams/armelf_phoenix.sh: Likewise.
	* emulparams/aarch64elf.sh: Likewise, and __data_start
	* emulparams/aarch64elf32.sh: Likewise.
	* emulparams/armelf.sh: Likewise.
	* emulparams/armnto.sh: Likewise.
	* emulparams/elf32bmip.sh: Remove duplicate ". = ." from
	OTHER_GOT_SYMBOLS.  PROVIDE _ftext, _fdata, and _fbss in shared libs.
	* emulparams/elf32bmipn32-defs.sh: Likewise.
	* emulparams/elf32frv.sh: PROVIDE __end and __data_start in shared libs.
	* emulparams/elf32lriscv-defs.sh: Tidy.
	* emulparams/elf32mcore.sh: PROVIDE __bss_start and _bss_end in
	shared libs
	* emulparams/elf32ppccommon.sh: PROVIDE __end in shared libs.
	* emulparams/elf32rl78.sh: Tidy.
	* emulparams/i386nto.sh: PROVIDE _btext in shared libs.
	* emulparams/shelf_nto.sh: Likewise.
	* emulparams/shlelf_nto.sh: Likewise.
	* emulparams/score3_elf.sh: PROVIDE _gp, _bss_start__, _bss_end__,
	__bss_end__, __end__, _fdata, _sdata_begin, and _bss_start in
	shared libs.
	* scripttempl/elf.sc: Don't use EXECUTABLE_SYMBOLS for shared
	libraries.  PROVIDE _edata, edata, __bss_start, and _end in shared
	libraries.
	* testsuite/ld-elf/pr23161.map,
	* testsuite/ld-elf/pr23161a.c,
	* testsuite/ld-elf/pr23161b.c,
	* testsuite/ld-elf/pr23161c.c,
	* testsuite/ld-elf/pr23161a.rd,
	* testsuite/ld-elf/pr23161b.rd,
	* testsuite/ld-elf/pr23161c.rd,
	* testsuite/ld-elf/pr23161d.rd: New tests.
	* testsuite/ld-elf/shared.exp: Run ld/23161 tests.
	* testsuite/ld-elf/pr23162.rd,
	* testsuite/ld-aarch64/ifunc-1-local.d,
	* testsuite/ld-aarch64/ifunc-1.d,
	* testsuite/ld-aarch64/ifunc-2-local.d,
	* testsuite/ld-aarch64/ifunc-2.d,
	* testsuite/ld-aarch64/ifunc-21.d,
	* testsuite/ld-aarch64/ifunc-3a.d,
	* testsuite/ld-alpha/tlsbin.rd,
	* testsuite/ld-alpha/tlsbin.sd,
	* testsuite/ld-alpha/tlsbinr.rd,
	* testsuite/ld-alpha/tlspic.rd,
	* testsuite/ld-alpha/tlspic.sd,
	* testsuite/ld-cris/dso-pltdis1.d,
	* testsuite/ld-cris/dso-pltdis2.d,
	* testsuite/ld-cris/dso12-pltdis.d,
	* testsuite/ld-cris/gotplt1.d,
	* testsuite/ld-cris/gotplt2.d,
	* testsuite/ld-cris/gotplt3.d,
	* testsuite/ld-cris/hiddef1.d,
	* testsuite/ld-cris/libdso-1.d,
	* testsuite/ld-cris/libdso-10.d,
	* testsuite/ld-cris/libdso-11.d,
	* testsuite/ld-cris/libdso-12.d,
	* testsuite/ld-cris/libdso-12b.d,
	* testsuite/ld-cris/libdso-12c.d,
	* testsuite/ld-cris/libdso-13.d,
	* testsuite/ld-cris/libdso-13b.d,
	* testsuite/ld-cris/libdso-14.d,
	* testsuite/ld-cris/libdso-15.d,
	* testsuite/ld-cris/libdso-15b.d,
	* testsuite/ld-cris/libdso-1c.d,
	* testsuite/ld-cris/libdso-1d.d,
	* testsuite/ld-cris/libdso-2.d,
	* testsuite/ld-cris/pic-gc-72.d,
	* testsuite/ld-cris/pic-gc-73.d,
	* testsuite/ld-cris/pr16044.d,
	* testsuite/ld-cris/pv32-1.d,
	* testsuite/ld-cris/tls-dso-dtpoffd2.d,
	* testsuite/ld-cris/tls-dso-dtpoffd4.d,
	* testsuite/ld-cris/tls-dso-tpoffgotcomm1.d,
	* testsuite/ld-cris/tls-gc-71.d,
	* testsuite/ld-cris/tls-gd-1.d,
	* testsuite/ld-cris/tls-gd-1h.d,
	* testsuite/ld-cris/tls-gd-2.d,
	* testsuite/ld-cris/tls-gd-2h.d,
	* testsuite/ld-cris/tls-ie-10.d,
	* testsuite/ld-cris/tls-ie-11.d,
	* testsuite/ld-cris/tls-ie-78.d,
	* testsuite/ld-cris/tls-ie-8.d,
	* testsuite/ld-cris/tls-ie-9.d,
	* testsuite/ld-cris/tls-js1.d,
	* testsuite/ld-cris/tls-ld-4.d,
	* testsuite/ld-cris/tls-ld-5.d,
	* testsuite/ld-cris/tls-ld-6.d,
	* testsuite/ld-cris/tls-ld-7.d,
	* testsuite/ld-cris/tls-ldgd-14.d,
	* testsuite/ld-cris/tls-ldgd-15.d,
	* testsuite/ld-cris/tls-ldgdex-14.d,
	* testsuite/ld-cris/tls-ldgdex-15.d,
	* testsuite/ld-cris/tls-ldgdx-14.d,
	* testsuite/ld-cris/tls-ldgdx-15.d,
	* testsuite/ld-cris/tls-legdx-16.d,
	* testsuite/ld-cris/tls-legdx-17.d,
	* testsuite/ld-cris/tls-local-54.d,
	* testsuite/ld-cris/tls-local-60.d,
	* testsuite/ld-cris/tls-local-61.d,
	* testsuite/ld-cris/tls-local-63.d,
	* testsuite/ld-cris/tls-local-64.d,
	* testsuite/ld-cris/tls-ok-30.d,
	* testsuite/ld-cris/tls-ok-32.d,
	* testsuite/ld-cris/tls-ok-34.d,
	* testsuite/ld-cris/tls-und-38.d,
	* testsuite/ld-cris/tls-und-42.d,
	* testsuite/ld-cris/tls-und-46.d,
	* testsuite/ld-cris/tls-und-50.d,
	* testsuite/ld-cris/weakhiddso.d,
	* testsuite/ld-cris/weakref2.d,
	* testsuite/ld-frv/fdpic-shared-1.d,
	* testsuite/ld-frv/fdpic-shared-2.d,
	* testsuite/ld-frv/fdpic-shared-3.d,
	* testsuite/ld-frv/fdpic-shared-4.d,
	* testsuite/ld-frv/fdpic-shared-5.d,
	* testsuite/ld-frv/fdpic-shared-7.d,
	* testsuite/ld-frv/fdpic-shared-8.d,
	* testsuite/ld-frv/tls-dynamic-2.d,
	* testsuite/ld-i386/ibt-plt-1.d,
	* testsuite/ld-i386/ibt-plt-2a.d,
	* testsuite/ld-i386/ibt-plt-2b.d,
	* testsuite/ld-i386/ibt-plt-2c.d,
	* testsuite/ld-i386/ibt-plt-2d.d,
	* testsuite/ld-i386/ibt-plt-3a.d,
	* testsuite/ld-i386/ibt-plt-3b.d,
	* testsuite/ld-i386/ibt-plt-3c.d,
	* testsuite/ld-i386/ibt-plt-3d.d,
	* testsuite/ld-i386/plt2.dd,
	* testsuite/ld-i386/pr20830.d,
	* testsuite/ld-i386/tlsbin-nacl.rd,
	* testsuite/ld-i386/tlsbin.rd,
	* testsuite/ld-i386/tlsbin2-nacl.rd,
	* testsuite/ld-i386/tlsbin2.rd,
	* testsuite/ld-i386/tlsbindesc-nacl.rd,
	* testsuite/ld-i386/tlsbindesc.rd,
	* testsuite/ld-i386/tlsdesc-nacl.rd,
	* testsuite/ld-i386/tlsdesc.rd,
	* testsuite/ld-i386/tlsgdesc-nacl.rd,
	* testsuite/ld-i386/tlsgdesc.rd,
	* testsuite/ld-i386/tlsnopic-nacl.rd,
	* testsuite/ld-i386/tlsnopic.dd,
	* testsuite/ld-i386/tlsnopic.rd,
	* testsuite/ld-i386/tlsnopic.sd,
	* testsuite/ld-i386/tlspic-nacl.rd,
	* testsuite/ld-i386/tlspic.rd,
	* testsuite/ld-i386/tlspic2-nacl.rd,
	* testsuite/ld-i386/tlspic2.rd,
	* testsuite/ld-ia64/merge1.d,
	* testsuite/ld-ia64/merge2.d,
	* testsuite/ld-ia64/merge3.d,
	* testsuite/ld-ia64/merge4.d,
	* testsuite/ld-ia64/merge5.d,
	* testsuite/ld-ia64/tlsbin.rd,
	* testsuite/ld-ia64/tlspic.rd,
	* testsuite/ld-ifunc/ifunc-2-i386-now.d,
	* testsuite/ld-ifunc/ifunc-2-local-i386-now.d,
	* testsuite/ld-ifunc/ifunc-2-local-x86-64-now.d,
	* testsuite/ld-ifunc/ifunc-2-local-x86-64.d,
	* testsuite/ld-ifunc/ifunc-2-x86-64-now.d,
	* testsuite/ld-ifunc/ifunc-2-x86-64.d,
	* testsuite/ld-ifunc/pr17154-i386-now.d,
	* testsuite/ld-ifunc/pr17154-i386.d,
	* testsuite/ld-ifunc/pr17154-x86-64-now.d,
	* testsuite/ld-ifunc/pr17154-x86-64.d,
	* testsuite/ld-m68k/tls-def-1.d,
	* testsuite/ld-m68k/tls-gd-1.d2,
	* testsuite/ld-metag/shared.d,
	* testsuite/ld-metag/stub_pic_app.d,
	* testsuite/ld-mips-elf/rel32-n32.d,
	* testsuite/ld-mips-elf/rel32-o32.d,
	* testsuite/ld-mips-elf/rel64.d,
	* testsuite/ld-powerpc/ambiguousv1.d,
	* testsuite/ld-powerpc/ambiguousv1b.d,
	* testsuite/ld-powerpc/ambiguousv2.d,
	* testsuite/ld-powerpc/ambiguousv2b.d,
	* testsuite/ld-powerpc/tlsexe.d,
	* testsuite/ld-powerpc/tlsexe.r,
	* testsuite/ld-powerpc/tlsexe32.d,
	* testsuite/ld-powerpc/tlsexe32.g,
	* testsuite/ld-powerpc/tlsexe32.r,
	* testsuite/ld-powerpc/tlsexetoc.d,
	* testsuite/ld-powerpc/tlsexetoc.r,
	* testsuite/ld-powerpc/tlsso.d,
	* testsuite/ld-powerpc/tlsso.r,
	* testsuite/ld-powerpc/tlsso32.g,
	* testsuite/ld-powerpc/tlsso32.r,
	* testsuite/ld-powerpc/tlstocso.d,
	* testsuite/ld-powerpc/tlstocso.g,
	* testsuite/ld-powerpc/tlstocso.r,
	* testsuite/ld-s390/gotreloc_31-1.dd,
	* testsuite/ld-s390/tlsbin.dd,
	* testsuite/ld-s390/tlsbin.rd,
	* testsuite/ld-s390/tlsbin_64.dd,
	* testsuite/ld-s390/tlsbin_64.rd,
	* testsuite/ld-s390/tlspic.rd,
	* testsuite/ld-s390/tlspic_64.rd,
	* testsuite/ld-sh/tlsbin-2.d,
	* testsuite/ld-sh/tlspic-2.d,
	* testsuite/ld-sparc/gotop32.rd,
	* testsuite/ld-sparc/gotop64.rd,
	* testsuite/ld-sparc/tlssunbin32.rd,
	* testsuite/ld-sparc/tlssunbin64.rd,
	* testsuite/ld-sparc/tlssunnopic32.rd,
	* testsuite/ld-sparc/tlssunnopic64.rd,
	* testsuite/ld-sparc/tlssunpic32.rd,
	* testsuite/ld-sparc/tlssunpic64.rd,
	* testsuite/ld-x86-64/bnd-branch-1-now.d,
	* testsuite/ld-x86-64/bnd-ifunc-1-now.d,
	* testsuite/ld-x86-64/bnd-ifunc-2-now.d,
	* testsuite/ld-x86-64/bnd-ifunc-2.d,
	* testsuite/ld-x86-64/bnd-plt-1-now.d,
	* testsuite/ld-x86-64/bnd-plt-1.d,
	* testsuite/ld-x86-64/ibt-plt-1-x32.d,
	* testsuite/ld-x86-64/ibt-plt-1.d,
	* testsuite/ld-x86-64/ibt-plt-2a-x32.d,
	* testsuite/ld-x86-64/ibt-plt-2a.d,
	* testsuite/ld-x86-64/ibt-plt-2b-x32.d,
	* testsuite/ld-x86-64/ibt-plt-2b.d,
	* testsuite/ld-x86-64/ibt-plt-2c-x32.d,
	* testsuite/ld-x86-64/ibt-plt-2c.d,
	* testsuite/ld-x86-64/ibt-plt-2d-x32.d,
	* testsuite/ld-x86-64/ibt-plt-2d.d,
	* testsuite/ld-x86-64/ibt-plt-3a-x32.d,
	* testsuite/ld-x86-64/ibt-plt-3a.d,
	* testsuite/ld-x86-64/ibt-plt-3b-x32.d,
	* testsuite/ld-x86-64/ibt-plt-3b.d,
	* testsuite/ld-x86-64/ibt-plt-3c-x32.d,
	* testsuite/ld-x86-64/ibt-plt-3c.d,
	* testsuite/ld-x86-64/ibt-plt-3d-x32.d,
	* testsuite/ld-x86-64/ibt-plt-3d.d,
	* testsuite/ld-x86-64/ilp32-4-nacl.d,
	* testsuite/ld-x86-64/ilp32-4.d,
	* testsuite/ld-x86-64/load1c-nacl.d,
	* testsuite/ld-x86-64/load1c.d,
	* testsuite/ld-x86-64/load1d-nacl.d,
	* testsuite/ld-x86-64/load1d.d,
	* testsuite/ld-x86-64/mpx3n.dd,
	* testsuite/ld-x86-64/mpx4.dd,
	* testsuite/ld-x86-64/mpx4n.dd,
	* testsuite/ld-x86-64/plt2.dd,
	* testsuite/ld-x86-64/pr14207.d,
	* testsuite/ld-x86-64/pr19162.d,
	* testsuite/ld-x86-64/pr20253-1f.d,
	* testsuite/ld-x86-64/pr20253-1l.d,
	* testsuite/ld-x86-64/pr20830a-now.d,
	* testsuite/ld-x86-64/pr20830a.d,
	* testsuite/ld-x86-64/pr20830b-now.d,
	* testsuite/ld-x86-64/pr20830b.d,
	* testsuite/ld-x86-64/pr21038a-now.d,
	* testsuite/ld-x86-64/pr21038a.d,
	* testsuite/ld-x86-64/pr21038b-now.d,
	* testsuite/ld-x86-64/pr21038b.d,
	* testsuite/ld-x86-64/pr21038c-now.d,
	* testsuite/ld-x86-64/pr21038c.d,
	* testsuite/ld-x86-64/tlsbin-nacl.rd,
	* testsuite/ld-x86-64/tlsbin.rd,
	* testsuite/ld-x86-64/tlsbin2-nacl.rd,
	* testsuite/ld-x86-64/tlsbin2.rd,
	* testsuite/ld-x86-64/tlsbindesc-nacl.rd,
	* testsuite/ld-x86-64/tlsbindesc.rd,
	* testsuite/ld-x86-64/tlsdesc-nacl.rd,
	* testsuite/ld-x86-64/tlsdesc.rd,
	* testsuite/ld-x86-64/tlsgdesc-nacl.rd,
	* testsuite/ld-x86-64/tlsgdesc.rd,
	* testsuite/ld-x86-64/tlspic-nacl.rd,
	* testsuite/ld-x86-64/tlspic.rd,
	* testsuite/ld-x86-64/tlspic2-nacl.rd,
	* testsuite/ld-x86-64/tlspic2.rd: Update.
2018-06-08 20:17:34 +09:30
..
emulparams Define various symbols conditionally in shared libraries 2018-06-08 20:17:34 +09:30
emultempl Remove sunos.em 2018-04-16 23:23:11 +09:30
po s12z regen 2018-05-25 16:05:30 +09:30
scripttempl Define various symbols conditionally in shared libraries 2018-06-08 20:17:34 +09:30
testsuite Define various symbols conditionally in shared libraries 2018-06-08 20:17:34 +09:30
.gitignore
aclocal.m4
ChangeLog Define various symbols conditionally in shared libraries 2018-06-08 20:17:34 +09:30
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-9197
ChangeLog-9899
config.in ld: Add --enable-separate-code 2018-02-27 11:34:29 -08:00
configure Bump version number to 2.30.52 2018-06-01 09:34:16 -07:00
configure.ac Add missing translations to ALL_LINGUAS 2018-03-01 09:17:02 +10:30
configure.host Remove m88k support 2018-04-16 15:23:38 +09:30
configure.tgt Add support for the Freescale s12z processor. 2018-05-18 15:26:18 +01:00
deffile.h Speed up direct linking with DLLs on Windows (2/2). 2018-04-04 12:13:05 +02:00
deffilep.y Speed up direct linking with DLLs on Windows (2/2). 2018-04-04 12:13:05 +02:00
dep-in.sed
elf-hints-local.h
fdl.texi
gen-doc.texi
genscrba.sh
genscripts.sh RISC-V: New emulations to make path searches follow glibc ABI. 2018-05-08 13:34:03 -07:00
h8-doc.texi
ld.h
ld.texinfo [MicroBlaze] PIC data text relative 2018-04-17 14:47:13 -07:00
ldbuildid.c
ldbuildid.h
ldcref.c ld error/warning messages 2018-02-26 10:51:12 +10:30
ldctor.c ld error/warning messages 2018-02-26 10:51:12 +10:30
ldctor.h
ldemul.c powerpc common-page-size 2018-04-14 17:56:40 +09:30
ldemul.h
ldexp.c ld: Hide symbols defined by HIDDEN/PROVIDE_HIDDEN 2018-05-21 20:39:30 -07:00
ldexp.h
ldfile.c ld error/warning messages 2018-02-26 10:51:12 +10:30
ldfile.h
ldgram.y ld error/warning messages 2018-02-26 10:51:12 +10:30
ldint.texinfo
ldlang.c Remove sh5 and sh64 support 2018-04-16 15:29:39 +09:30
ldlang.h
ldlex-wrapper.c
ldlex.h [MicroBlaze] PIC data text relative 2018-04-17 14:47:13 -07:00
ldlex.l Use %pI, %pR, %pS, %pT in place of %I, %R, %S and %T. 2018-02-19 23:55:53 +10:30
ldmain.c [MicroBlaze] PIC data text relative 2018-04-17 14:47:13 -07:00
ldmain.h
ldmisc.c ld error/warning messages 2018-02-26 10:51:12 +10:30
ldmisc.h
ldver.c
ldver.h
ldwrite.c ld error/warning messages 2018-02-26 10:51:12 +10:30
ldwrite.h
lexsup.c [MicroBlaze] PIC data text relative 2018-04-17 14:47:13 -07:00
MAINTAINERS
Makefile.am armelf_fbsd and armelf_fuchsia dependencies 2018-06-06 21:31:41 +09:30
Makefile.in armelf_fbsd and armelf_fuchsia dependencies 2018-06-06 21:31:41 +09:30
mri.c Remove m68k-aout and m68k-coff support 2018-04-16 15:31:36 +09:30
mri.h
NEWS Add blurb about linker changes for Cygwin and Mingw targets. 2018-04-04 12:18:09 +02:00
pe-dll.c Remove arm-epoc-pe support 2018-04-16 20:29:05 +09:30
pe-dll.h Speed up direct linking with DLLs on Windows (1/2). 2018-04-04 12:07:50 +02:00
pep-dll.c Speed up direct linking with DLLs on Windows (1/2). 2018-04-04 12:07:50 +02:00
pep-dll.h Speed up direct linking with DLLs on Windows (1/2). 2018-04-04 12:07:50 +02:00
plugin.c PR23254, ld.bfd mishandles file pointers while scanning archive 2018-06-05 22:39:11 +09:30
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.texinfo), as well as the
  beginnings of an internals manual (ldint.texinfo).

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.texinfo 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) 2012-2018 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.