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[18/21] Add -bexpall and -bexpfull
- From: Richard Sandiford <richards at transitive dot com>
- To: binutils at sourceware dot org
- Date: Tue, 10 Mar 2009 14:49:14 +0000
- Subject: [18/21] Add -bexpall and -bexpfull
- References: <g4y6vd7a4x.fsf@richards-desktop.transitives.com>
The native AIX linker has two options called -bexpall and -bexpfull.
This patch adds support to the GNU linker.
Support for -bexpfull-like behaviour is already there for non-gc links,
in the form of -unix. We simply need to extend it to gc links by
marking all symbols that need to be exported. Support for -bexpall is a
simple extension of this.
The current code doesn't export symbols from archives that contain
shared objects:
/* We don't export a symbol which is being defined by an object
included from an archive which contains a shared object. The
rationale is that if an archive contains both an unshared and
a shared object, then there must be some reason that the
unshared object is unshared, and we don't want to start
providing a shared version of it. In particular, this solves
a bug involving the _savefNN set of functions. gcc will call
those functions without providing a slot to restore the TOC,
so it is essential that these functions be linked in directly
and not from a shared object, which means that a shared
object which also happens to link them in must not export
them. This is confusing, but I haven't been able to think of
a different approach. Note that the symbols can, of course,
be exported explicitly. */
I think this diverges from the native linker, but the reason is
explained fairly well, so I kept it.
The existing code actually walks the archive for every symbol it
is given, which seems rather inefficient, but I kept that too.
Adding some sort of cache is a possible future refinement.
There's no documentation or help output for the new options because
I couldn't find any for the existing ones. I'm afraid fixing that
is beyond what I have time for right now.
OK to install?
Richard
include/coff/
* xcoff.h (XCOFF_EXPALL, XCOFF_EXPFULL): New flags.
(xcoff_loader_info): Add auto_export_flags.
bfd/
* bfd-in.h (bfd_xcoff_size_dynamic_sections): Replace the
bfd_boolean export_defineds parameter with an unsigned int
auto_export_flags parameter.
* bfd-in2.h: Regenerate.
* xcofflink.c (xcoff_archive_contains_shared_object_p): New function,
split out from xcoff_build_ldsyms.
(xcoff_covered_by_expall_p): New function.
(xcoff_auto_export_p): New function, split out from xcoff_build_ldsyms
but with extra code to handle -bexpfull and -bexpall.
(xcoff_mark_auto_exports): New function.
(xcoff_build_ldsyms): Use xcoff_auto_export_p to decide whether
a function should be automatically exported.
(bfd_xcoff_size_dynamic_sections): Replace the export_defineds
parameter with an auto_export_flags parameter. Update ldinfo
accordingly. Use xcoff_mark_auto_exports to mark all automatically-
exported symbols.
ld/
* emultempl/aix.em (auto_export_flags): New variable.
(explicit_auto_export_flags): Likewise.
(OPTION_EXPALL, OPTION_EXPFULL): New enum values.
(OPTION_NOEXPALL, OPTION_NOEXPFULL): Likewise.
(gld${EMULATION_NAME}_add_options): Add -bexpall, -bexpfull,
-bnoexpall and -bnoexpfull.
(gld${EMULATION_NAME}_handle_option): Handle them.
(gld${EMULATION_NAME}_before_allocation): Update the call to
bfd_size_dynamic_sections.
ld/testsuite/
* ld-powerpc/aix-export-1-all.dd, ld-powerpc/aix-export-1-full.dd,
ld-powerpc/aix-export-1a.s, ld-powerpc/aix-export-1b.s: New tests.
* ld-powerpc/aix52.exp: Run them.
Index: include/coff/xcoff.h
===================================================================
--- include/coff/xcoff.h 2009-03-10 13:51:47.000000000 +0000
+++ include/coff/xcoff.h 2009-03-10 13:52:51.000000000 +0000
@@ -394,6 +394,9 @@ struct xcoff_link_hash_table
asection *special_sections[XCOFF_NUMBER_OF_SPECIAL_SECTIONS];
};
+/* These flags indicate which of -bexpall and -bexpfull are in effect. */
+#define XCOFF_EXPALL 1
+#define XCOFF_EXPFULL 2
/* This structure is used to pass information through
xcoff_link_hash_traverse. */
@@ -409,8 +412,8 @@ struct xcoff_loader_info
/* Link information structure. */
struct bfd_link_info *info;
- /* Whether all defined symbols should be exported. */
- bfd_boolean export_defineds;
+ /* A mask of XCOFF_EXPALL and XCOFF_EXPFULL flags. */
+ unsigned int auto_export_flags;
/* Number of ldsym structures. */
size_t ldsym_count;
Index: bfd/bfd-in.h
===================================================================
--- bfd/bfd-in.h 2009-03-10 13:38:52.000000000 +0000
+++ bfd/bfd-in.h 2009-03-10 13:52:51.000000000 +0000
@@ -779,7 +779,7 @@ typedef struct _bfd_window
extern bfd_boolean bfd_xcoff_size_dynamic_sections
(bfd *, struct bfd_link_info *, const char *, const char *,
unsigned long, unsigned long, unsigned long, bfd_boolean,
- int, bfd_boolean, bfd_boolean, struct bfd_section **, bfd_boolean);
+ int, bfd_boolean, unsigned int, struct bfd_section **, bfd_boolean);
extern bfd_boolean bfd_xcoff_link_generate_rtinit
(bfd *, const char *, const char *, bfd_boolean);
Index: bfd/bfd-in2.h
===================================================================
--- bfd/bfd-in2.h 2009-03-10 13:38:52.000000000 +0000
+++ bfd/bfd-in2.h 2009-03-10 13:52:51.000000000 +0000
@@ -786,7 +786,7 @@ typedef struct _bfd_window
extern bfd_boolean bfd_xcoff_size_dynamic_sections
(bfd *, struct bfd_link_info *, const char *, const char *,
unsigned long, unsigned long, unsigned long, bfd_boolean,
- int, bfd_boolean, bfd_boolean, struct bfd_section **, bfd_boolean);
+ int, bfd_boolean, unsigned int, struct bfd_section **, bfd_boolean);
extern bfd_boolean bfd_xcoff_link_generate_rtinit
(bfd *, const char *, const char *, bfd_boolean);
Index: bfd/xcofflink.c
===================================================================
--- bfd/xcofflink.c 2009-03-10 13:52:29.000000000 +0000
+++ bfd/xcofflink.c 2009-03-10 13:52:51.000000000 +0000
@@ -2313,6 +2313,97 @@ xcoff_set_import_path (struct bfd_link_i
return TRUE;
}
+/* Return true if the given bfd contains at least one shared object. */
+
+static bfd_boolean
+xcoff_archive_contains_shared_object_p (bfd *archive)
+{
+ bfd *member;
+
+ member = bfd_openr_next_archived_file (archive, NULL);
+ while (member != NULL && (member->flags & DYNAMIC) == 0)
+ member = bfd_openr_next_archived_file (archive, member);
+ return member != NULL;
+}
+
+/* Symbol H qualifies for export by -bexpfull. Return true if it also
+ qualifies for export by -bexpall. */
+
+static bfd_boolean
+xcoff_covered_by_expall_p (struct xcoff_link_hash_entry *h)
+{
+ /* Exclude symbols beginning with '_'. */
+ if (h->root.root.string[0] == '_')
+ return FALSE;
+
+ /* Exclude archive members that would otherwise be unreferenced. */
+ if ((h->flags & XCOFF_MARK) == 0
+ && (h->root.type == bfd_link_hash_defined
+ || h->root.type == bfd_link_hash_defweak)
+ && h->root.u.def.section->owner != NULL
+ && h->root.u.def.section->owner->my_archive != NULL)
+ return FALSE;
+
+ return TRUE;
+}
+
+/* Return true if symbol H qualifies for the forms of automatic export
+ specified by AUTO_EXPORT_FLAGS. */
+
+static bfd_boolean
+xcoff_auto_export_p (struct xcoff_link_hash_entry *h,
+ unsigned int auto_export_flags)
+{
+ /* Don't automatically export things that were explicitly exported. */
+ if ((h->flags & XCOFF_EXPORT) != 0)
+ return FALSE;
+
+ /* Don't export things that we don't define. */
+ if ((h->flags & XCOFF_DEF_REGULAR) == 0)
+ return FALSE;
+
+ /* Don't export functions; export their descriptors instead. */
+ if (h->root.root.string[0] == '.')
+ return FALSE;
+
+ /* We don't export a symbol which is being defined by an object
+ included from an archive which contains a shared object. The
+ rationale is that if an archive contains both an unshared and
+ a shared object, then there must be some reason that the
+ unshared object is unshared, and we don't want to start
+ providing a shared version of it. In particular, this solves
+ a bug involving the _savefNN set of functions. gcc will call
+ those functions without providing a slot to restore the TOC,
+ so it is essential that these functions be linked in directly
+ and not from a shared object, which means that a shared
+ object which also happens to link them in must not export
+ them. This is confusing, but I haven't been able to think of
+ a different approach. Note that the symbols can, of course,
+ be exported explicitly. */
+ if (h->root.type == bfd_link_hash_defined
+ || h->root.type == bfd_link_hash_defweak)
+ {
+ bfd *owner;
+
+ owner = h->root.u.def.section->owner;
+ if (owner != NULL
+ && owner->my_archive != NULL
+ && xcoff_archive_contains_shared_object_p (owner->my_archive))
+ return FALSE;
+ }
+
+ /* Otherwise, all symbols are exported by -bexpfull. */
+ if ((auto_export_flags & XCOFF_EXPFULL) != 0)
+ return TRUE;
+
+ /* Despite its name, -bexpall exports most but not all symbols. */
+ if ((auto_export_flags & XCOFF_EXPALL) != 0
+ && xcoff_covered_by_expall_p (h))
+ return TRUE;
+
+ return FALSE;
+}
+
/* Mark a symbol as not being garbage, including the section in which
it is defined. */
@@ -2878,6 +2969,24 @@ bfd_xcoff_record_link_assignment (bfd *o
return TRUE;
}
+/* An xcoff_link_hash_traverse callback for which DATA points to an
+ xcoff_loader_info. Mark all symbols that should be automatically
+ exported. */
+
+static bfd_boolean
+xcoff_mark_auto_exports (struct xcoff_link_hash_entry *h, void *data)
+{
+ struct xcoff_loader_info *ldinfo;
+
+ ldinfo = (struct xcoff_loader_info *) data;
+ if (xcoff_auto_export_p (h, ldinfo->auto_export_flags))
+ {
+ if (!xcoff_mark_symbol (ldinfo->info, h))
+ ldinfo->failed = TRUE;
+ }
+ return TRUE;
+}
+
/* Add a symbol to the .loader symbols, if necessary. */
/* INPUT_BFD has an external symbol associated with hash table entry H
@@ -2939,50 +3048,8 @@ xcoff_build_ldsyms (struct xcoff_link_ha
/* If all defined symbols should be exported, mark them now. We
don't want to export the actual functions, just the function
descriptors. */
- if (ldinfo->export_defineds
- && (h->flags & XCOFF_DEF_REGULAR) != 0
- && h->root.root.string[0] != '.')
- {
- bfd_boolean export;
-
- /* We don't export a symbol which is being defined by an object
- included from an archive which contains a shared object. The
- rationale is that if an archive contains both an unshared and
- a shared object, then there must be some reason that the
- unshared object is unshared, and we don't want to start
- providing a shared version of it. In particular, this solves
- a bug involving the _savefNN set of functions. gcc will call
- those functions without providing a slot to restore the TOC,
- so it is essential that these functions be linked in directly
- and not from a shared object, which means that a shared
- object which also happens to link them in must not export
- them. This is confusing, but I haven't been able to think of
- a different approach. Note that the symbols can, of course,
- be exported explicitly. */
- export = TRUE;
- if ((h->root.type == bfd_link_hash_defined
- || h->root.type == bfd_link_hash_defweak)
- && h->root.u.def.section->owner != NULL
- && h->root.u.def.section->owner->my_archive != NULL)
- {
- bfd *arbfd, *member;
-
- arbfd = h->root.u.def.section->owner->my_archive;
- member = bfd_openr_next_archived_file (arbfd, NULL);
- while (member != NULL)
- {
- if ((member->flags & DYNAMIC) != 0)
- {
- export = FALSE;
- break;
- }
- member = bfd_openr_next_archived_file (arbfd, member);
- }
- }
-
- if (export)
- h->flags |= XCOFF_EXPORT;
- }
+ if (xcoff_auto_export_p (h, ldinfo->auto_export_flags))
+ h->flags |= XCOFF_EXPORT;
/* We don't want to garbage collect symbols which are not defined in
XCOFF files. This is a convenient place to mark them. */
@@ -3181,10 +3248,9 @@ xcoff_keep_symbol_p (struct bfd_link_inf
-bmaxdata linker option). GC is whether to do garbage collection
(the -bgc linker option). MODTYPE is the module type (the
-bmodtype linker option). TEXTRO is whether the text section must
- be read only (the -btextro linker option). EXPORT_DEFINEDS is
- whether all defined symbols should be exported (the -unix linker
- option). SPECIAL_SECTIONS is set by this routine to csects with
- magic names like _end. */
+ be read only (the -btextro linker option). AUTO_EXPORT_FLAGS
+ is a mask of XCOFF_EXPALL and XCOFF_EXPFULL. SPECIAL_SECTIONS
+ is set by this routine to csects with magic names like _end. */
bfd_boolean
bfd_xcoff_size_dynamic_sections (bfd *output_bfd,
@@ -3197,7 +3263,7 @@ bfd_xcoff_size_dynamic_sections (bfd *ou
bfd_boolean gc,
int modtype,
bfd_boolean textro,
- bfd_boolean export_defineds,
+ unsigned int auto_export_flags,
asection **special_sections,
bfd_boolean rtld)
{
@@ -3225,7 +3291,7 @@ bfd_xcoff_size_dynamic_sections (bfd *ou
ldinfo.failed = FALSE;
ldinfo.output_bfd = output_bfd;
ldinfo.info = info;
- ldinfo.export_defineds = export_defineds;
+ ldinfo.auto_export_flags = auto_export_flags;
ldinfo.ldsym_count = 0;
ldinfo.string_size = 0;
ldinfo.strings = NULL;
@@ -3328,6 +3394,13 @@ bfd_xcoff_size_dynamic_sections (bfd *ou
if (info->fini_function != NULL
&& !xcoff_mark_symbol_by_name (info, info->fini_function, 0))
goto error_return;
+ if (auto_export_flags != 0)
+ {
+ xcoff_link_hash_traverse (xcoff_hash_table (info),
+ xcoff_mark_auto_exports, &ldinfo);
+ if (ldinfo.failed)
+ goto error_return;
+ }
xcoff_sweep (info);
xcoff_hash_table (info)->gc = TRUE;
}
Index: ld/emultempl/aix.em
===================================================================
--- ld/emultempl/aix.em 2009-03-10 13:46:23.000000000 +0000
+++ ld/emultempl/aix.em 2009-03-10 13:52:51.000000000 +0000
@@ -84,6 +84,14 @@ static unsigned short modtype = ('1' <<
permitted). */
static int textro;
+/* A mask of XCOFF_EXPALL and XCOFF_EXPFULL flags, as set by their
+ associated -b and -bno options. */
+static unsigned int auto_export_flags;
+
+/* A mask of auto_export_flags bits that were explicitly set on the
+ command line. */
+static unsigned int explicit_auto_export_flags;
+
/* Whether to implement Unix like linker semantics. */
static int unix_ld;
@@ -156,6 +164,8 @@ enum
OPTION_AUTOIMP,
OPTION_ERNOTOK,
OPTION_EROK,
+ OPTION_EXPALL,
+ OPTION_EXPFULL,
OPTION_EXPORT,
OPTION_IMPORT,
OPTION_INITFINI,
@@ -164,6 +174,8 @@ enum
OPTION_MAXSTACK,
OPTION_MODTYPE,
OPTION_NOAUTOIMP,
+ OPTION_NOEXPALL,
+ OPTION_NOEXPFULL,
OPTION_NOSTRCMPCT,
OPTION_PD,
OPTION_PT,
@@ -201,6 +213,8 @@ gld${EMULATION_NAME}_add_options
{"bernotok", no_argument, NULL, OPTION_ERNOTOK},
{"berok", no_argument, NULL, OPTION_EROK},
{"berrmsg", no_argument, NULL, OPTION_IGNORE},
+ {"bexpall", no_argument, NULL, OPTION_EXPALL},
+ {"bexpfull", no_argument, NULL, OPTION_EXPFULL},
{"bexport", required_argument, NULL, OPTION_EXPORT},
{"bf", no_argument, NULL, OPTION_ERNOTOK},
{"bgc", no_argument, &gc, 1},
@@ -216,6 +230,8 @@ gld${EMULATION_NAME}_add_options
{"bM", required_argument, NULL, OPTION_MODTYPE},
{"bmodtype", required_argument, NULL, OPTION_MODTYPE},
{"bnoautoimp", no_argument, NULL, OPTION_NOAUTOIMP},
+ {"bnoexpall", no_argument, NULL, OPTION_NOEXPALL},
+ {"bnoexpfull", no_argument, NULL, OPTION_NOEXPFULL},
{"bnodelcsect", no_argument, NULL, OPTION_IGNORE},
{"bnoentry", no_argument, NULL, OPTION_IGNORE},
{"bnogc", no_argument, &gc, 0},
@@ -388,6 +404,16 @@ gld${EMULATION_NAME}_handle_option (int
link_info.unresolved_syms_in_shared_libs = RM_IGNORE;
break;
+ case OPTION_EXPALL:
+ auto_export_flags |= XCOFF_EXPALL;
+ explicit_auto_export_flags |= XCOFF_EXPALL;
+ break;
+
+ case OPTION_EXPFULL:
+ auto_export_flags |= XCOFF_EXPFULL;
+ explicit_auto_export_flags |= XCOFF_EXPFULL;
+ break;
+
case OPTION_EXPORT:
gld${EMULATION_NAME}_read_file (optarg, FALSE);
break;
@@ -444,6 +470,16 @@ gld${EMULATION_NAME}_handle_option (int
link_info.static_link = TRUE;
break;
+ case OPTION_NOEXPALL:
+ auto_export_flags &= ~XCOFF_EXPALL;
+ explicit_auto_export_flags |= XCOFF_EXPALL;
+ break;
+
+ case OPTION_NOEXPFULL:
+ auto_export_flags &= ~XCOFF_EXPFULL;
+ explicit_auto_export_flags |= XCOFF_EXPFULL;
+ break;
+
case OPTION_NOSTRCMPCT:
link_info.traditional_format = TRUE;
break;
@@ -624,7 +660,7 @@ gld${EMULATION_NAME}_before_allocation (
".data",
".bss"
};
- unsigned int i;
+ unsigned int i, flags;
/* Handle the import and export files, if any. */
for (fl = import_files; fl != NULL; fl = fl->next)
@@ -710,11 +746,16 @@ gld${EMULATION_NAME}_before_allocation (
}
}
+ /* Default to -bexpfull for SVR4-like semantics. */
+ flags = (unix_ld ? XCOFF_EXPFULL : 0);
+ flags &= ~explicit_auto_export_flags;
+ flags |= auto_export_flags;
+
/* Let the XCOFF backend set up the .loader section. */
if (!bfd_xcoff_size_dynamic_sections
(link_info.output_bfd, &link_info, libpath, entry_symbol.name, file_align,
maxstack, maxdata, gc && !unix_ld ? TRUE : FALSE,
- modtype, textro ? TRUE : FALSE, unix_ld, special_sections,
+ modtype, textro ? TRUE : FALSE, flags, special_sections,
rtld ? TRUE : FALSE))
einfo ("%P%F: failed to set dynamic section sizes: %E\n");
Index: ld/testsuite/ld-powerpc/aix-export-1-all.dd
===================================================================
--- /dev/null 2009-02-06 09:11:03.343159000 +0000
+++ ld/testsuite/ld-powerpc/aix-export-1-all.dd 2009-03-10 13:52:51.000000000 +0000
@@ -0,0 +1,11 @@
+
+.*
+
+
+Disassembly of section \.data:
+
+0*10000000 <main1>:
+ *10000000: 10 00 00 04 .*
+
+0*10000004 <lib1>:
+ *10000004: 11 11 00 01 .*
Index: ld/testsuite/ld-powerpc/aix-export-1-full.dd
===================================================================
--- /dev/null 2009-02-06 09:11:03.343159000 +0000
+++ ld/testsuite/ld-powerpc/aix-export-1-full.dd 2009-03-10 13:52:51.000000000 +0000
@@ -0,0 +1,21 @@
+
+.*
+
+
+Disassembly of section .data:
+
+0*10000000 <main1>:
+ *10000000: 10 00 00 08 .*
+
+0*10000004 <_main2>:
+ *10000004: 10 00 00 0c .*
+
+0*10000008 <lib1>:
+ *10000008: 11 11 00 01 .*
+
+0*1000000c <_lib2>:
+ *1000000c: 11 11 00 02 .*
+
+0*10000010 <lib3>:
+ *10000010: 11 11 00 03 .*
+ *10000014: 00 00 00 00 .*
Index: ld/testsuite/ld-powerpc/aix-export-1a.s
===================================================================
--- /dev/null 2009-02-06 09:11:03.343159000 +0000
+++ ld/testsuite/ld-powerpc/aix-export-1a.s 2009-03-10 13:52:51.000000000 +0000
@@ -0,0 +1,14 @@
+ .globl lib1
+ .csect lib1[RW]
+lib1:
+ .long 0x11110001
+
+ .globl _lib2
+ .csect _lib2[RW]
+_lib2:
+ .long 0x11110002
+
+ .globl lib3
+ .csect lib3[RW]
+lib3:
+ .long 0x11110003
Index: ld/testsuite/ld-powerpc/aix-export-1b.s
===================================================================
--- /dev/null 2009-02-06 09:11:03.343159000 +0000
+++ ld/testsuite/ld-powerpc/aix-export-1b.s 2009-03-10 13:52:51.000000000 +0000
@@ -0,0 +1,9 @@
+ .globl main1
+ .csect main1[RW]
+main1:
+ .long lib1
+
+ .globl _main2
+ .csect _main2[RW]
+_main2:
+ .long _lib2
Index: ld/testsuite/ld-powerpc/aix52.exp
===================================================================
--- ld/testsuite/ld-powerpc/aix52.exp 2009-03-10 13:52:29.000000000 +0000
+++ ld/testsuite/ld-powerpc/aix52.exp 2009-03-10 13:52:51.000000000 +0000
@@ -108,6 +108,26 @@ set aix52tests {
{nm -D aix-no-dup-syms-1-dso.dnd} {objdump -R aix-no-dup-syms-1-dso.drd}}
"aix-no-dup-syms-1.so"}
+ {"Export test 1 (archive)" ""
+ "" {aix-export-1a.s}
+ {} "libaix-export-1.a"}
+
+ {"Export test 1 (object)" "-r"
+ "" {aix-export-1b.s}
+ {} "aix-export-1.o"}
+
+ {"Export test 1 (-bexpall)"
+ "-shared -bexpall tmpdir/aix-export-1.o -Ltmpdir -laix-export-1"
+ "" {}
+ {{objdump -dj.data aix-export-1-all.dd}}
+ "aix-export-1-all.so"}
+
+ {"Export test 1 (-bexpfull)"
+ "-shared -bexpfull tmpdir/aix-export-1.o -Ltmpdir -laix-export-1"
+ "" {}
+ {{objdump -dj.data aix-export-1-full.dd}}
+ "aix-export-1-full.so"}
+
{"Garbage collection test 1"
"-shared -binitfini:init_function:fini_function -bE:aix-gc-1.ex"
"" {aix-gc-1.s}