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Re: RFC: Speeding up libstdc++.so with --dynamic-list-data
On Tue, Jan 09, 2007 at 09:42:40AM -0800, H. J. Lu wrote:
> On Tue, Jan 09, 2007 at 06:18:19AM -0800, H. J. Lu wrote:
> > On Tue, Jan 09, 2007 at 02:01:53PM +0000, Andrew Haley wrote:
> > > H. J. Lu writes:
> > > > On Tue, Jan 09, 2007 at 01:51:00PM +0000, Andrew Haley wrote:
> > > > > H. J. Lu writes:
> > > > > > On Tue, Jan 09, 2007 at 01:38:00PM +0000, Andrew Haley wrote:
> > > > > > > H. J. Lu writes:
> > > > > > > > I am enclosing a patch to implement a new linker swicth,
> > > > > > > > --dynamic-list-data. It is -Bsymbolic for function symbols only.
> > > > > > > > I tried it with C, C++, Java and Fortran on Linux/ia32, Linux/x86-64
> > > > > > > > and Linux/ia64. There are only a few regressions. The function calls
> > > > > > > > within the new resulting DSOs will bind locally. It speeds up
> > > > > > > > the enclosed C++ testcase by
> > > > > > > >
> > > > > > > > 1. 23% on ia64.
> > > > > > > > 2. 6% on ia32.
> > > > > > > > 3. 3% on x86-64.
> > > > > > > >
> > > > > > > > Should we consider such optimization?
> > > > > > >
> > > > > > > That's a terrible name for the option. What does it mean?
> > > > > >
> > > > > > It is an extension of the current command line options:
> > > > > >
> > > > > > --dynamic-list-cpp-typeinfo Use C++ typeinfo dynamic list
> > > > > > --dynamic-list FILE Read dynamic list
> > > > >
> > > > > But you said it was like -Bsymbolic for function symbols only. What
> > > > > is the connection between C++ typeinfo and that? (Hint: Java doesn't
> > > > > use C++ typeinfo, but -Bsymbolic for function symbols only would be
> > > > > very useful.)
> > > >
> > > > --dynamic-list is a generic linker feature. Users have to provide a
> > > > list of symbols, which will be bound dynamically and everything else
> > > > is bound locally. --dynamic-list-cpp-typeinfo includes a prefined
> > > > list for C++ typeinfo. --dynamic-list-data puts data symbols on
> > > > the dynamic list.
> > >
> > > OK, so in the case of --dynamic-list-data, there is no user-supplied
> > > list. Instead, there's (conceptually) an automatically-generated
> > > list, which contains every symbol that doesn't point to a function.
> > > Can't you just call the new option -Bsymbolic-functions? At least
> > > then people like me might have an outside chance of remembering it.
> >
> > Here is the updated patch to use -Bsymbolic-functions instead.
> >
>
> I just realized that --dynamic-list-data is -Bsymbolic for function
> symbols only when you build shared libraries. We can use
> --dynamic-list-data on executables to make global data symbols
> dynamic so that dlopened shared libraries can reference them. We can
> make -Bsymbolic-functions an alias of --dynamic-list-data. But
> we still need --dynamic-list-data since -Bsymbolic doesn't apply to
> executables.
Here is the updated patch with testcases and document change.
H.J.
----
bfd/
2007-01-09 H.J. Lu <hongjiu.lu@intel.com>
PR ld/3831
* elf-bfd.h (bfd_elf_link_mark_dynamic_symbol): Add an
argument, Elf_Internal_Sym *.
* elflink.c (bfd_elf_link_mark_dynamic_symbol): Mark a data
symbol dynamic if info->dynamic_data is TRUE.
(bfd_elf_record_link_assignment): Updated call to
bfd_elf_record_link_assignment.
(_bfd_elf_merge_symbol): Likewise. Always call
bfd_elf_link_mark_dynamic_symbol.
include/
2007-01-09 H.J. Lu <hongjiu.lu@intel.com>
PR ld/3831
* bfdlink.h (bfd_link_info): Rename dynamic to dynamic_list.
Add dynamic and dynamic_data.
ld/
2007-01-05 H.J. Lu <hongjiu.lu@intel.com>
PR ld/3831
* NEWS: Mention -Bsymbolic-functions and --dynamic-list-data.
* ld.texinfo: Document -Bsymbolic-functions and
--dynamic-list-data.
* ldlang.c (lang_process): Change link_info.dynamic to
link_info.dynamic_list.
(lang_append_dynamic_list): Likewise.
* ldmain.c (main): Likewise. Initialize link_info.dynamic and
link_info.dynamic_data to FALSE.
* lexsup.c (option_values): Add OPTION_DYNAMIC_LIST_DATA.
(ld_options): Add entries for -Bsymbolic-functions and
--dynamic-list-data. Make -Bsymbolic-functions an alias of
--dynamic-list-data.
(parse_args): Change link_info.dynamic to link_info.dynamic_list.
Set link_info.dynamic_data to TRUE for --dynamic-list-data. Set
link_info.dynamic to TRUE for --dynamuc-list*.
ld/testsuite/
2007-01-09 H.J. Lu <hongjiu.lu@intel.com>
* ld-elf/shared.exp: Add tests for --dynamic-list-data.
--- binutils/bfd/elf-bfd.h.data 2007-01-09 09:00:51.000000000 -0800
+++ binutils/bfd/elf-bfd.h 2007-01-09 09:00:51.000000000 -0800
@@ -1858,7 +1858,8 @@ extern int bfd_elf_link_record_local_dyn
(struct bfd_link_info *, bfd *, long);
extern void bfd_elf_link_mark_dynamic_symbol
- (struct bfd_link_info *, struct elf_link_hash_entry *);
+ (struct bfd_link_info *, struct elf_link_hash_entry *,
+ Elf_Internal_Sym *);
extern bfd_boolean _bfd_elf_close_and_cleanup
(bfd *);
--- binutils/bfd/elflink.c.data 2007-01-09 09:00:51.000000000 -0800
+++ binutils/bfd/elflink.c 2007-01-09 09:59:22.000000000 -0800
@@ -454,14 +454,22 @@ bfd_elf_link_record_dynamic_symbol (stru
void
bfd_elf_link_mark_dynamic_symbol (struct bfd_link_info *info,
- struct elf_link_hash_entry *h)
+ struct elf_link_hash_entry *h,
+ Elf_Internal_Sym *sym)
{
- struct bfd_elf_dynamic_list *d = info->dynamic;
+ struct bfd_elf_dynamic_list *d = info->dynamic_list;
- if (d == NULL || info->relocatable)
+ /* It may be called more than once on the same H. */
+ if(h->dynamic || info->relocatable)
return;
- if ((*d->match) (&d->head, NULL, h->root.root.string))
+ if ((info->dynamic_data
+ && (h->type == STT_OBJECT
+ || (sym != NULL
+ && ELF_ST_TYPE (sym->st_info) == STT_OBJECT)))
+ || (d != NULL
+ && h->root.type == bfd_link_hash_new
+ && (*d->match) (&d->head, NULL, h->root.root.string)))
h->dynamic = 1;
}
@@ -499,7 +507,7 @@ bfd_elf_record_link_assignment (bfd *out
if (h->root.type == bfd_link_hash_new)
{
- bfd_elf_link_mark_dynamic_symbol (info, h);
+ bfd_elf_link_mark_dynamic_symbol (info, h, NULL);
h->non_elf = 0;
}
@@ -906,13 +914,17 @@ _bfd_elf_merge_symbol (bfd *abfd,
|| h->root.type == bfd_link_hash_warning)
h = (struct elf_link_hash_entry *) h->root.u.i.link;
+ /* We have to check it for every instance since the first few may be
+ refereences and not all compilers emit symbol type for undefined
+ symbols. */
+ bfd_elf_link_mark_dynamic_symbol (info, h, sym);
+
/* If we just created the symbol, mark it as being an ELF symbol.
Other than that, there is nothing to do--there is no merge issue
with a newly defined symbol--so we just return. */
if (h->root.type == bfd_link_hash_new)
{
- bfd_elf_link_mark_dynamic_symbol (info, h);
h->non_elf = 0;
return TRUE;
}
--- binutils/include/bfdlink.h.data 2006-10-30 15:25:51.000000000 -0800
+++ binutils/include/bfdlink.h 2007-01-09 09:58:52.000000000 -0800
@@ -340,6 +340,13 @@ struct bfd_link_info
caching ELF symbol buffer. */
unsigned int reduce_memory_overheads: 1;
+ /* TRUE if all data symbols should be dynamic. */
+ unsigned int dynamic_data: 1;
+
+ /* TRUE if some symbols have to be dynamic, controlled by
+ --dynamic-list command line options. */
+ unsigned int dynamic: 1;
+
/* What to do with unresolved symbols in an object file.
When producing executables the default is GENERATE_ERROR.
When producing shared libraries the default is IGNORE. The
@@ -440,7 +447,7 @@ struct bfd_link_info
bfd_vma relro_start, relro_end;
/* List of symbols should be dynamic. */
- struct bfd_elf_dynamic_list *dynamic;
+ struct bfd_elf_dynamic_list *dynamic_list;
};
/* This structures holds a set of callback functions. These are
--- binutils/ld/NEWS.data 2006-09-20 04:35:09.000000000 -0700
+++ binutils/ld/NEWS 2007-01-09 11:18:06.000000000 -0800
@@ -1,4 +1,7 @@
-*- text -*-
+* ELF: Add -Bsymbolic-functions and --dynamic-list-data, builtin list
+ for --dynamic-list, which put global data symbols on the dynamic list.
+
* Add support for x86_64 PE+ target.
* Add support for Score target.
--- binutils/ld/ld.texinfo.data 2006-12-05 11:28:02.000000000 -0800
+++ binutils/ld/ld.texinfo 2007-01-09 11:14:06.000000000 -0800
@@ -1130,6 +1130,14 @@ for a program linked against a shared li
within the shared library. This option is only meaningful on ELF
platforms which support shared libraries.
+@kindex -Bsymbolic-functions
+@item -Bsymbolic-functions
+When creating a shared library, bind references to global function
+symbols to the definition within the shared library, if any.
+@option{-Bsymbolic-functions} is an alias for @option{--dynamic-list-data}.
+This option is only meaningful on ELF platforms which support shared
+libraries.
+
@kindex --dynamic-list=@var{dynamic-list-file}
@item --dynamic-list=@var{dynamic-list-file}
Specify the name of a dynamic list file to the linker. This is
@@ -1143,6 +1151,10 @@ which support shared libraries.
The format of the dynamic list is the same as the version node without
scope and node name. See @ref{VERSION} for more information.
+@kindex --dynamic-list-data
+@item --dynamic-list-data
+Include all global data symbols to the dynamic list.
+
@kindex --dynamic-list-cpp-typeinfo
@item --dynamic-list-cpp-typeinfo
Provide the builtin dynamic list for C++ runtime type identification.
--- binutils/ld/ldlang.c.data 2007-01-09 09:00:51.000000000 -0800
+++ binutils/ld/ldlang.c 2007-01-09 09:00:51.000000000 -0800
@@ -5732,8 +5732,8 @@ void
lang_process (void)
{
/* Finalize dynamic list. */
- if (link_info.dynamic)
- lang_finalize_version_expr_head (&link_info.dynamic->head);
+ if (link_info.dynamic_list)
+ lang_finalize_version_expr_head (&link_info.dynamic_list->head);
current_target = default_target;
@@ -7047,13 +7047,13 @@ lang_add_unique (const char *name)
void
lang_append_dynamic_list (struct bfd_elf_version_expr *dynamic)
{
- if (link_info.dynamic)
+ if (link_info.dynamic_list)
{
struct bfd_elf_version_expr *tail;
for (tail = dynamic; tail->next != NULL; tail = tail->next)
;
- tail->next = link_info.dynamic->head.list;
- link_info.dynamic->head.list = dynamic;
+ tail->next = link_info.dynamic_list->head.list;
+ link_info.dynamic_list->head.list = dynamic;
}
else
{
@@ -7062,7 +7062,7 @@ lang_append_dynamic_list (struct bfd_elf
d = xcalloc (1, sizeof *d);
d->head.list = dynamic;
d->match = lang_vers_match;
- link_info.dynamic = d;
+ link_info.dynamic_list = d;
}
}
--- binutils/ld/ldmain.c.data 2006-10-30 15:25:51.000000000 -0800
+++ binutils/ld/ldmain.c 2007-01-09 10:00:33.000000000 -0800
@@ -318,7 +318,9 @@ main (int argc, char **argv)
link_info.warn_shared_textrel = FALSE;
link_info.gc_sections = FALSE;
link_info.print_gc_sections = FALSE;
- link_info.dynamic = NULL;
+ link_info.dynamic = FALSE;
+ link_info.dynamic_list = NULL;
+ link_info.dynamic_data = FALSE;
link_info.reduce_memory_overheads = FALSE;
config.maxpagesize = 0;
--- binutils/ld/lexsup.c.data 2006-10-30 15:25:51.000000000 -0800
+++ binutils/ld/lexsup.c 2007-01-09 10:00:23.000000000 -0800
@@ -109,6 +109,7 @@ enum option_values
OPTION_VERSION_EXPORTS_SECTION,
OPTION_DYNAMIC_LIST,
OPTION_DYNAMIC_LIST_CPP_TYPEINFO,
+ OPTION_DYNAMIC_LIST_DATA,
OPTION_WARN_COMMON,
OPTION_WARN_CONSTRUCTORS,
OPTION_WARN_FATAL,
@@ -503,6 +504,10 @@ static const struct ld_option ld_options
OPTION_VERSION_EXPORTS_SECTION },
'\0', N_("SYMBOL"), N_("Take export symbols list from .exports, using\n"
"\t\t\t\tSYMBOL as the version."), TWO_DASHES },
+ { {"Bsymbolic-functions", no_argument, NULL, OPTION_DYNAMIC_LIST_DATA},
+ '\0', NULL, N_("Bind global function references locally"), ONE_DASH },
+ { {"dynamic-list-data", no_argument, NULL, OPTION_DYNAMIC_LIST_DATA},
+ '\0', NULL, N_("Add data symbols to dynamic list"), TWO_DASHES },
{ {"dynamic-list-cpp-typeinfo", no_argument, NULL, OPTION_DYNAMIC_LIST_CPP_TYPEINFO},
'\0', NULL, N_("Use C++ typeinfo dynamic list"), TWO_DASHES },
{ {"dynamic-list", required_argument, NULL, OPTION_DYNAMIC_LIST},
@@ -1244,8 +1249,13 @@ parse_args (unsigned argc, char **argv)
.exports sections. */
command_line.version_exports_section = optarg;
break;
+ case OPTION_DYNAMIC_LIST_DATA:
+ link_info.dynamic_data = TRUE;
+ link_info.dynamic = TRUE;
+ break;
case OPTION_DYNAMIC_LIST_CPP_TYPEINFO:
lang_append_dynamic_list_cpp_typeinfo ();
+ link_info.dynamic = TRUE;
break;
case OPTION_DYNAMIC_LIST:
/* This option indicates a small script that only specifies
@@ -1260,6 +1270,7 @@ parse_args (unsigned argc, char **argv)
parser_input = input_dynamic_list;
yyparse ();
}
+ link_info.dynamic = TRUE;
break;
case OPTION_WARN_COMMON:
config.warn_common = TRUE;
--- binutils/ld/testsuite/ld-elf/shared.exp.data 2006-10-18 09:23:24.000000000 -0700
+++ binutils/ld/testsuite/ld-elf/shared.exp 2007-01-09 10:46:32.000000000 -0800
@@ -72,15 +72,27 @@ set build_tests {
{"Build libdl2a.so with --dynamic-list=dl2.list"
"-shared -Wl,--dynamic-list=dl2.list" "-fPIC"
{dl2.c dl2xxx.c} {} "libdl2a.so"}
+ {"Build libdl2a.so with --dynamic-list-data"
+ "-shared -Wl,--dynamic-list-data" "-fPIC"
+ {dl2.c dl2xxx.c} {} "libdl2a.so"}
{"Build libdl2b.so with --dynamic-list=dl2.list and dl2xxx.list"
"-shared -Wl,--dynamic-list=dl2.list,--dynamic-list=dl2xxx.list" "-fPIC"
{dl2.c dl2xxx.c} {} "libdl2b.so"}
+ {"Build libdl2b.so with --dynamic-list-data and dl2xxx.list"
+ "-shared -Wl,--dynamic-list-data,--dynamic-list=dl2xxx.list" "-fPIC"
+ {dl2.c dl2xxx.c} {} "libdl2b.so"}
{"Build libdl4a.so with --dynamic-list=dl4.list"
"-shared -Wl,--dynamic-list=dl4.list" "-fPIC"
{dl4.c dl4xxx.c} {} "libdl4a.so"}
+ {"Build libdl4a.so with --dynamic-list-data"
+ "-shared -Wl,--dynamic-list-data" "-fPIC"
+ {dl4.c dl4xxx.c} {} "libdl4a.so"}
{"Build libdl4b.so with --dynamic-list=dl4.list and dl4xxx.list"
"-shared -Wl,--dynamic-list=dl4.list,--dynamic-list=dl4xxx.list" "-fPIC"
{dl4.c dl4xxx.c} {} "libdl4b.so"}
+ {"Build libdl4b.so with --dynamic-list-data and dl4xxx.list"
+ "-shared -Wl,--dynamic-list-data,--dynamic-list=dl4xxx.list" "-fPIC"
+ {dl4.c dl4xxx.c} {} "libdl4b.so"}
}
set run_tests {
@@ -120,9 +132,12 @@ set run_tests {
{"Run hidden libbar.so with versioned libfoo.so"
"tmpdir/libbarhfoov.so tmpdir/libfoov.so" ""
{main.c} "hidden" "hidden.out"}
- {"Run with dlopen on libdl1.so"
+ {"Run dl1 with --dynamic-list=dl1.list and dlopen on libdl1.so"
"--dynamic-list=dl1.list -ldl" ""
{dl1main.c} "dl1" "dl1.out"}
+ {"Run dl1 with --dynamic-list-data and dlopen on libdl1.so"
+ "--dynamic-list-data -ldl" ""
+ {dl1main.c} "dl1" "dl1.out"}
{"Run with libdl2a.so"
"tmpdir/libdl2a.so" ""
{dl2main.c} "dl2a" "dl2a.out"}