* Re: GNU ld and -init/-fini
1999-07-01 0:00 GNU ld and -init/-fini mark
@ 1999-07-01 0:00 ` Richard Henderson
1999-07-01 0:00 ` Ian Lance Taylor
1 sibling, 0 replies; 4+ messages in thread
From: Richard Henderson @ 1999-07-01 0:00 UTC (permalink / raw)
To: mark; +Cc: binutils
On Mon, Jun 21, 1999 at 04:09:57PM -0700, mark@codesourcery.com wrote:
> There do not seem to be equivalent GNU ld switches. What is the
> method used on Linux, etc. in order to make the same sort of thing
> happen?
GNU ld knows about `_init' and `_fini' as magic symbols.
Not really ideal, I know.
r~
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: GNU ld and -init/-fini
1999-07-01 0:00 ` Ian Lance Taylor
@ 1999-07-01 0:00 ` mark
0 siblings, 0 replies; 4+ messages in thread
From: mark @ 1999-07-01 0:00 UTC (permalink / raw)
To: ian; +Cc: binutils
>>>>> "Ian" == Ian Lance Taylor <ian@zembu.com> writes:
Ian> I think it would be appropriate to add -init and -fini
Ian> options to work for any ELF target, and permit them to
Ian> override the default of _init and _fini.
I agree. Attached is a patch to do just that. OK to check in?
As an aside, using this patch, I have managed to use the (unsubmitted)
IRIX6 N32 port of GNU ld to fully bootstrap GCC, and there are no
immediately apparent regressions in the testsuites (where GNU ld is
used to link the various tests, naturally.) I'm still testing, and
there's some code cleanup to do, and a few corner cases to handle, but
I'm nearly ready to make this code available. Then, I'll just have to
sneak it past your eagle eyes. :-)
--
Mark Mitchell mark@codesourcery.com
CodeSourcery, LLC http://www.codesourcery.com
1999-06-22 Mark Mitchell <mark@codesourcery.com>
* bfdlink.h (struct bfd_link_hash_entry): Add init_function and
fini_function.
1999-06-22 Mark Mitchell <mark@codesourcery.com>
* elflink.h (size_dynamic_sections): Use user-specified init/fini
functions instead of _init/_fini if requested.
1999-06-22 Mark Mitchell <mark@codesourcery.com>
* ldmain.c (main): Initialize link_info.init_function and
link_info.fini_function.
* lexsup.c (OPTION_INIT): New macro.
(OPTION_FINI): Likewise.
(ld_options): Add descriptions for them.
(parse_args): Handle them.
Index: include/bfdlink.h
===================================================================
RCS file: /cvs/binutils/binutils/include/bfdlink.h,v
retrieving revision 1.1.1.1
diff -u -p -r1.1.1.1 bfdlink.h
--- bfdlink.h 1999/05/03 07:29:01 1.1.1.1
+++ bfdlink.h 1999/06/23 00:16:33
@@ -237,6 +237,13 @@ struct bfd_link_info
MPC860 C0 (or earlier) should be checked for and modified. It gives the
number of bytes that should be checked at the end of each text page. */
int mpc860c0;
+
+ /* The function to call when the executable or shared object is
+ loaded. */
+ const char *init_function;
+ /* The function to call when the executable or shared object is
+ unloaded. */
+ const char *fini_function;
};
/* This structures holds a set of callback functions. These are
Index: bfd/elflink.h
===================================================================
RCS file: /cvs/binutils/binutils/bfd/elflink.h,v
retrieving revision 1.6
diff -u -p -r1.6 elflink.h
--- elflink.h 1999/06/22 13:57:15 1.6
+++ elflink.h 1999/06/23 00:16:37
@@ -2589,8 +2589,14 @@ NAME(bfd_elf,size_dynamic_sections) (out
/* Add some entries to the .dynamic section. We fill in some of the
values later, in elf_bfd_final_link, but we must add the entries
now so that we know the final size of the .dynamic section. */
- h = elf_link_hash_lookup (elf_hash_table (info), "_init", false,
- false, false);
+
+ /* If there are initialization and/or finalization functions to
+ call then add the corresponding DT_INIT/DT_FINI entries. */
+ h = (info->init_function
+ ? elf_link_hash_lookup (elf_hash_table (info),
+ info->init_function, false,
+ false, false)
+ : NULL);
if (h != NULL
&& (h->elf_link_hash_flags & (ELF_LINK_HASH_REF_REGULAR
| ELF_LINK_HASH_DEF_REGULAR)) != 0)
@@ -2598,8 +2604,11 @@ NAME(bfd_elf,size_dynamic_sections) (out
if (! elf_add_dynamic_entry (info, DT_INIT, 0))
return false;
}
- h = elf_link_hash_lookup (elf_hash_table (info), "_fini", false,
- false, false);
+ h = (info->init_function
+ ? elf_link_hash_lookup (elf_hash_table (info),
+ info->fini_function, false,
+ false, false)
+ : NULL);
if (h != NULL
&& (h->elf_link_hash_flags & (ELF_LINK_HASH_REF_REGULAR
| ELF_LINK_HASH_DEF_REGULAR)) != 0)
@@ -2607,6 +2616,7 @@ NAME(bfd_elf,size_dynamic_sections) (out
if (! elf_add_dynamic_entry (info, DT_FINI, 0))
return false;
}
+
strsize = _bfd_stringtab_size (elf_hash_table (info)->dynstr);
if (! elf_add_dynamic_entry (info, DT_HASH, 0)
|| ! elf_add_dynamic_entry (info, DT_STRTAB, 0)
@@ -4159,15 +4169,11 @@ elf_bfd_final_link (abfd, info)
{
default:
break;
-
- /* SVR4 linkers seem to set DT_INIT and DT_FINI based on
- magic _init and _fini symbols. This is pretty ugly,
- but we are compatible. */
case DT_INIT:
- name = "_init";
+ name = info->init_function;
goto get_sym;
case DT_FINI:
- name = "_fini";
+ name = info->fini_function;
get_sym:
{
struct elf_link_hash_entry *h;
Index: ld/ld.texinfo
===================================================================
RCS file: /cvs/binutils/binutils/ld/ld.texinfo,v
retrieving revision 1.3
diff -u -p -r1.3 ld.texinfo
--- ld.texinfo 1999/06/14 01:40:24 1.3
+++ ld.texinfo 1999/06/23 00:16:45
@@ -404,6 +404,14 @@ purpose: the @code{-b}, @code{--format},
environment variable. The @sc{gnu} linker will ignore the @code{-F}
option when not creating an ELF shared object.
+@cindex finalization function
+@kindex -fini
+@item -fini @var{name}
+When creating an ELF executable or shared object, call NAME when the
+executable or shared object is unloaded, by setting DT_FINI to the
+address of the function. By default, the linker uses @code{_fini} as
+the function to call.
+
@kindex -g
@item -g
Ignored. Provided for compatibility with other tools.
@@ -433,6 +441,14 @@ field rather than the using the file nam
@cindex incremental link
@item -i
Perform an incremental link (same as option @samp{-r}).
+
+@cindex initialization function
+@kindex -init
+@item -init @var{name}
+When creating an ELF executable or shared object, call NAME when the
+executable or shared object is loaded, by setting DT_INIT to the address
+of the function. By default, the linker uses @code{_init} as the
+function to call.
@cindex archive files, from cmd line
@kindex -l@var{archive}
Index: ld/ldmain.c
===================================================================
RCS file: /cvs/binutils/binutils/ld/ldmain.c,v
retrieving revision 1.1.1.1
diff -u -p -r1.1.1.1 ldmain.c
--- ldmain.c 1999/05/03 07:29:07 1.1.1.1
+++ ldmain.c 1999/06/23 00:16:46
@@ -231,7 +231,11 @@ main (argc, argv)
link_info.notice_hash = NULL;
link_info.wrap_hash = NULL;
link_info.mpc860c0 = 0;
-
+ /* SVR4 linkers seem to set DT_INIT and DT_FINI based on magic _init
+ and _fini symbols. We are compatible. */
+ link_info.init_function = "_init";
+ link_info.fini_function = "_fini";
+
ldfile_add_arch ("");
config.make_executable = true;
Index: ld/lexsup.c
===================================================================
RCS file: /cvs/binutils/binutils/ld/lexsup.c,v
retrieving revision 1.3
diff -u -p -r1.3 lexsup.c
--- lexsup.c 1999/06/09 05:35:55 1.3
+++ lexsup.c 1999/06/23 00:16:47
@@ -120,6 +120,8 @@ int parsing_defsym = 0;
#define OPTION_NO_CHECK_SECTIONS (OPTION_CHECK_SECTIONS + 1)
#define OPTION_MPC860C0 (OPTION_NO_CHECK_SECTIONS + 1)
#define OPTION_NO_UNDEFINED (OPTION_MPC860C0 + 1)
+#define OPTION_INIT (OPTION_NO_UNDEFINED + 1)
+#define OPTION_FINI (OPTION_INIT + 1)
/* The long options. This structure is used for both the option
parsing and the help text. */
@@ -360,7 +362,11 @@ static const struct ld_option ld_options
{ {"wrap", required_argument, NULL, OPTION_WRAP},
'\0', N_("SYMBOL"), N_("Use wrapper functions for SYMBOL"), TWO_DASHES },
{ {"mpc860c0", optional_argument, NULL, OPTION_MPC860C0},
- '\0', N_("[=WORDS]"), N_("Modify problematic branches in last WORDS (1-10,\n\t\t\t\tdefault 5) words of a page"), TWO_DASHES }
+ '\0', N_("[=WORDS]"), N_("Modify problematic branches in last WORDS (1-10,\n\t\t\t\tdefault 5) words of a page"), TWO_DASHES },
+ { {"init", required_argument, NULL, OPTION_INIT},
+ '\0', N_("SYMBOL"), N_("Call SYMBOL at load-time"), ONE_DASH },
+ { {"fini", required_argument, NULL, OPTION_FINI},
+ '\0', N_("SYMBOL"), N_("Call SYMBOL at unload-time"), ONE_DASH },
};
#define OPTION_COUNT ((int) (sizeof ld_options / sizeof ld_options[0]))
@@ -988,6 +994,14 @@ the GNU General Public License. This pr
}
command_line.relax = true;
break;
+
+ case OPTION_INIT:
+ link_info.init_function = optarg;
+ break;
+
+ case OPTION_FINI:
+ link_info.fini_function = optarg;
+ break;
}
}
^ permalink raw reply [flat|nested] 4+ messages in thread
* GNU ld and -init/-fini
@ 1999-07-01 0:00 mark
1999-07-01 0:00 ` Richard Henderson
1999-07-01 0:00 ` Ian Lance Taylor
0 siblings, 2 replies; 4+ messages in thread
From: mark @ 1999-07-01 0:00 UTC (permalink / raw)
To: binutils
The IRIX 6 linker provdides -init and -fini switches. These switches
set DT_INIT and DT_FINI flags in the dynamic table, which cause the
named functions to be executed at initialization/finalization time.
GCC uses these to call global constructors when a shared library is
loaded.
There do not seem to be equivalent GNU ld switches. What is the
method used on Linux, etc. in order to make the same sort of thing
happen?
--
Mark Mitchell mark@codesourcery.com
CodeSourcery, LLC http://www.codesourcery.com
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: GNU ld and -init/-fini
1999-07-01 0:00 GNU ld and -init/-fini mark
1999-07-01 0:00 ` Richard Henderson
@ 1999-07-01 0:00 ` Ian Lance Taylor
1999-07-01 0:00 ` mark
1 sibling, 1 reply; 4+ messages in thread
From: Ian Lance Taylor @ 1999-07-01 0:00 UTC (permalink / raw)
To: mark; +Cc: binutils
From: mark@codesourcery.com
Date: Mon, 21 Jun 1999 16:09:57 -0700
The IRIX 6 linker provdides -init and -fini switches. These switches
set DT_INIT and DT_FINI flags in the dynamic table, which cause the
named functions to be executed at initialization/finalization time.
GCC uses these to call global constructors when a shared library is
loaded.
There do not seem to be equivalent GNU ld switches. What is the
method used on Linux, etc. in order to make the same sort of thing
happen?
As Richard said, the GNU linker recognizes _init and _fini specially.
It sets DT_INIT to the value of the _init symbol, and sets DT_FINI to
the value of the _fini symbol. This convention was taken from SVR4,
and indeed it is required in order to work on SVR4 and Solaris.
I think it would be appropriate to add -init and -fini options to work
for any ELF target, and permit them to override the default of _init
and _fini.
Ian
^ permalink raw reply [flat|nested] 4+ messages in thread
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1999-07-01 0:00 GNU ld and -init/-fini mark
1999-07-01 0:00 ` Richard Henderson
1999-07-01 0:00 ` Ian Lance Taylor
1999-07-01 0:00 ` mark
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