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[PATCH] Add AS_NEEDED () to INPUT () and GROUP () commands in linker scripts
- From: Jakub Jelinek <jakub at redhat dot com>
- To: binutils at sources dot redhat dot com
- Cc: Ulrich Drepper <drepper at redhat dot com>
- Date: Thu, 20 Jan 2005 11:13:30 +0100
- Subject: [PATCH] Add AS_NEEDED () to INPUT () and GROUP () commands in linker scripts
- Reply-to: Jakub Jelinek <jakub at redhat dot com>
Hi!
ATM it is impossible to link a shared library that uses TLS global or
local dynamic models with -Wl,-z,defs on Linux.
The reason is that __tls_get_addr and similar functions are defined/exported
from the dynamic linker, but the dynamic linker is not added as a
dependency.
On the other side, using something like:
/* GNU ld script
Use the shared library, but some functions are only in
the static library, so try that secondarily. */
OUTPUT_FORMAT(elf64-x86-64)
GROUP ( /lib64/libc.so.6 /usr/lib64/libc_nonshared.a /lib64/ld-linux-x86-64.so.2 )
in /usr/lib64/libc.so means unnecessary DT_NEEDED for the vast majority
of shared libraries.
We have --as-needed, but so far lacked the ability to set this (temporarily)
from linker scripts.
With the patch below, glibc can use
...
GROUP ( /lib64/libc.so.6 /usr/lib64/libc_nonshared.a AS_NEEDED ( /lib64/ld-linux-x86-64.so.2 ) )
where as_needed will be temporarily set to TRUE for all the files listed
between AS_NEEDED's parens and reset back to the previous setting
afterwards.
Ok to commit?
2005-01-20 Jakub Jelinek <jakub@redhat.com>
* ldgram.y (AS_NEEDED): New token.
(input_list): Handle AS_NEEDED ( input_list ).
* ldlex.l (AS_NEEDED): Add.
* ld.texinfo: Document AS_NEEDED ().
* NEWS: Mention AS_NEEDED ().
--- ld/ldgram.y.jj 2004-12-09 14:21:39.000000000 +0100
+++ ld/ldgram.y 2005-01-20 10:56:08.028812831 +0100
@@ -1,6 +1,6 @@
/* A YACC grammar to parse a superset of the AT&T linker scripting language.
Copyright 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
- 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
+ 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
Written by Steve Chamberlain of Cygnus Support (steve@cygnus.com).
This file is part of GNU ld.
@@ -144,7 +144,7 @@ static int error_index;
%token STARTUP HLL SYSLIB FLOAT NOFLOAT NOCROSSREFS
%token ORIGIN FILL
%token LENGTH CREATE_OBJECT_SYMBOLS INPUT GROUP OUTPUT CONSTRUCTORS
-%token ALIGNMOD AT SUBALIGN PROVIDE
+%token ALIGNMOD AT SUBALIGN PROVIDE AS_NEEDED
%type <token> assign_op atype attributes_opt sect_constraint
%type <name> filename
%token CHIP LIST SECT ABSOLUTE LOAD NEWLINE ENDWORD ORDER NAMEWORD ASSERT_K
@@ -372,6 +372,18 @@ input_list:
| input_list LNAME
{ lang_add_input_file($2,lang_input_file_is_l_enum,
(char *)NULL); }
+ | AS_NEEDED '('
+ { $<integer>$ = as_needed; as_needed = TRUE; }
+ input_list ')'
+ { as_needed = $<integer>3; }
+ | input_list ',' AS_NEEDED '('
+ { $<integer>$ = as_needed; as_needed = TRUE; }
+ input_list ')'
+ { as_needed = $<integer>5; }
+ | input_list AS_NEEDED '('
+ { $<integer>$ = as_needed; as_needed = TRUE; }
+ input_list ')'
+ { as_needed = $<integer>4; }
;
sections:
--- ld/ldlex.l.jj 2004-12-09 14:21:40.000000000 +0100
+++ ld/ldlex.l 2005-01-20 10:24:16.068318830 +0100
@@ -1,7 +1,7 @@
%{
/* Copyright 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
- 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
+ 2000, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
This file is part of GLD, the Gnu Linker.
@@ -269,6 +269,7 @@ V_IDENTIFIER [*?.$_a-zA-Z\[\]\-\!\^\\]([
<BOTH,SCRIPT>"OUTPUT" { RTOKEN(OUTPUT);}
<BOTH,SCRIPT>"INPUT" { RTOKEN(INPUT);}
<EXPRESSION,BOTH,SCRIPT>"GROUP" { RTOKEN(GROUP);}
+<EXPRESSION,BOTH,SCRIPT>"AS_NEEDED" { RTOKEN(AS_NEEDED);}
<EXPRESSION,BOTH,SCRIPT>"DEFINED" { RTOKEN(DEFINED);}
<BOTH,SCRIPT>"CREATE_OBJECT_SYMBOLS" { RTOKEN(CREATE_OBJECT_SYMBOLS);}
<BOTH,SCRIPT>"CONSTRUCTORS" { RTOKEN( CONSTRUCTORS);}
--- ld/NEWS.jj 2005-01-20 09:50:41.000000000 +0100
+++ ld/NEWS 2005-01-20 11:03:17.617311825 +0100
@@ -1,5 +1,8 @@
-*- text -*-
+* New linker script construct AS_NEEDED(), which sets the --as-needed flag
+ for input files listed inside of it.
+
* A new command-line option, --sysroot, can be used to override the
default sysroot location. It only applies to toolchains that were
configured using --with-sysroot.
--- ld/ld.texinfo.jj 2005-01-20 09:50:43.000000000 +0100
+++ ld/ld.texinfo 2005-01-20 10:24:26.559450407 +0100
@@ -1,7 +1,7 @@
\input texinfo
@setfilename ld.info
@c Copyright 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
-@c 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
+@c 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
@syncodeindex ky cp
@include configdoc.texi
@c (configdoc.texi is generated by the Makefile)
@@ -2576,6 +2576,18 @@ files should all be archives, and they a
new undefined references are created. See the description of @samp{-(}
in @ref{Options,,Command Line Options}.
+@item AS_NEEDED(@var{file}, @var{file}, @dots{})
+@itemx AS_NEEDED(@var{file} @var{file} @dots{})
+@kindex AS_NEEDED(@var{files})
+This construct can appear only inside of the @code{INPUT} or @code{GROUP}
+commands, among other filenames. The files listed will be handled
+as if they appear directly in the @code{INPUT} or @code{GROUP} commands,
+with the exception of ELF shared libraries, that will be added only
+when they are actually needed. This construct essentially enables
+@option{--as-needed} option for all the files listed inside of it
+and restores previous @option{--as-needed} resp. @option{--no-as-needed}
+setting afterwards.
+
@item OUTPUT(@var{filename})
@kindex OUTPUT(@var{filename})
@cindex output file name in linker scripot
Jakub