On Sat, May 23, 2020 at 2:56 PM Fangrui Song wrote: > > On 2020-05-23, H.J. Lu wrote: > >On Sat, May 23, 2020 at 11:29 AM Fangrui Song wrote: > >> > >> On 2020-05-23, H.J. Lu wrote: > >> >From: Fangrui Song > >> > > >> >--export-dynamic-symbol-list is like a dynamic list, but without > >> >the symbolic property for unspecified symbols. > >> > > >> >When creating an executable, --export-dynamic-symbol-list is treated > >> >like --dynamic-list. > >> > > >> >When creating a shared library, it is treated like --dynamic-list if > >> >-Bsymbolic or --dynamic-list are used, otherwise, it is ignored, so > >> >that references to matched symbols will not be bound to the definitions > >> >within the shared library. > >> > > >> >2020-05-XX Fangrui Song > >> > H.J. Lu > >> > > >> > PR ld/25910 > >> > * NEWS: Mention --export-dynamic-symbol[-list]. > >> > * ld.texi: Document --export-dynamic-symbol[-list]. > >> > * ldgram.y: Pass current_dynamic_list_p to > >> > lang_append_dynamic_list. > >> > * ldlang.c (current_dynamic_list_p): New. > >> > (ang_append_dynamic_list): Updated to take a pointer to > >> > struct bfd_elf_dynamic_list * argument instead of using > >> > link_info.dynamic_list. > >> > (lang_append_dynamic_list_cpp_typeinfo): Pass > >> > &link_info.dynamic_list to ang_append_dynamic_list. > >> > (lang_append_dynamic_list_cpp_new): Likewise. > >> > * ldlang.h (current_dynamic_list_p): New. > >> > (lang_append_dynamic_list): Add a pointer to > >> > struct bfd_elf_dynamic_list * argument. > >> > * ldlex.h (option_values): Add OPTION_EXPORT_DYNAMIC_SYMBOL and > >> > OPTION_EXPORT_DYNAMIC_SYMBOL_LIST. > >> > * lexsup.c (ld_options): Add entries for > >> > OPTION_EXPORT_DYNAMIC_SYMBOL and > >> > OPTION_EXPORT_DYNAMIC_SYMBOL_LIST. > >> > (parse_args): Handle --export-dynamic-symbol and > >> > --export-dynamic-symbol-list. > >> > * testsuite/ld-dynamic/export-dynamic-symbol-1.d: New. > >> > * testsuite/ld-dynamic/export-dynamic-symbol-2.d: New. > >> > * testsuite/ld-dynamic/export-dynamic-symbol-glob.d: New. > >> > * testsuite/ld-dynamic/export-dynamic-symbol-list-1.d: New. > >> > * testsuite/ld-dynamic/export-dynamic-symbol-list-2.d: New. > >> > * testsuite/ld-dynamic/export-dynamic-symbol-list-glob.d: New. > >> > * testsuite/ld-dynamic/export-dynamic-symbol.exp: New. > >> > * testsuite/ld-dynamic/export-dynamic-symbol.s: New. > >> > * testsuite/ld-dynamic/foo-bar.list: New. > >> > * testsuite/ld-dynamic/foo.list: New. > >> > * testsuite/ld-dynamic/foo.s: New. > >> > * testsuite/ld-dynamic/fstar.list: New. > >> > * testsuite/ld-elf/dlempty.list: New. > >> > * testsuite/ld-elf/shared.exp: Add tests for > >> > --export-dynamic-symbol and --export-dynamic-symbol-list. > >> >--- > >> > ld/NEWS | 3 + > >> > ld/ld.texi | 18 +++++ > >> > ld/ldgram.y | 2 +- > >> > ld/ldlang.c | 16 ++-- > >> > ld/ldlang.h | 5 +- > >> > ld/ldlex.h | 2 + > >> > ld/lexsup.c | 75 +++++++++++++++++++ > >> > .../ld-dynamic/export-dynamic-symbol-1.d | 9 +++ > >> > .../ld-dynamic/export-dynamic-symbol-2.d | 9 +++ > >> > .../ld-dynamic/export-dynamic-symbol-glob.d | 8 ++ > >> > .../ld-dynamic/export-dynamic-symbol-list-1.d | 9 +++ > >> > .../ld-dynamic/export-dynamic-symbol-list-2.d | 9 +++ > >> > .../export-dynamic-symbol-list-glob.d | 8 ++ > >> > .../ld-dynamic/export-dynamic-symbol.exp | 39 ++++++++++ > >> > .../ld-dynamic/export-dynamic-symbol.s | 9 +++ > >> > ld/testsuite/ld-dynamic/foo-bar.list | 1 + > >> > ld/testsuite/ld-dynamic/foo.list | 1 + > >> > ld/testsuite/ld-dynamic/foo.s | 4 + > >> > ld/testsuite/ld-dynamic/fstar.list | 1 + > >> > ld/testsuite/ld-elf/dlempty.list | 3 + > >> > ld/testsuite/ld-elf/shared.exp | 36 +++++++++ > >> > 21 files changed, 258 insertions(+), 9 deletions(-) > >> > create mode 100644 ld/testsuite/ld-dynamic/export-dynamic-symbol-1.d > >> > create mode 100644 ld/testsuite/ld-dynamic/export-dynamic-symbol-2.d > >> > create mode 100644 ld/testsuite/ld-dynamic/export-dynamic-symbol-glob.d > >> > create mode 100644 ld/testsuite/ld-dynamic/export-dynamic-symbol-list-1.d > >> > create mode 100644 ld/testsuite/ld-dynamic/export-dynamic-symbol-list-2.d > >> > create mode 100644 ld/testsuite/ld-dynamic/export-dynamic-symbol-list-glob.d > >> > create mode 100644 ld/testsuite/ld-dynamic/export-dynamic-symbol.exp > >> > create mode 100644 ld/testsuite/ld-dynamic/export-dynamic-symbol.s > >> > create mode 100644 ld/testsuite/ld-dynamic/foo-bar.list > >> > create mode 100644 ld/testsuite/ld-dynamic/foo.list > >> > create mode 100644 ld/testsuite/ld-dynamic/foo.s > >> > create mode 100644 ld/testsuite/ld-dynamic/fstar.list > >> > create mode 100644 ld/testsuite/ld-elf/dlempty.list > >> > > >> >diff --git a/ld/NEWS b/ld/NEWS > >> >index 9f5bbe51cf..870c480bde 100644 > >> >--- a/ld/NEWS > >> >+++ b/ld/NEWS > >> >@@ -1,5 +1,8 @@ > >> > -*- text -*- > >> > > >> >+* Add ELF linker command-line options, --export-dynamic-symbol and > >> >+ --export-dynamic-symbol-list, to make symbols dynamic. > >> >+ > >> > * Add command-line options --enable-non-contiguous-regions and > >> > --enable-non-contiguous-regions-warnings. > >> > > >> >diff --git a/ld/ld.texi b/ld/ld.texi > >> >index 4dc78e65fa..92e47c6324 100644 > >> >--- a/ld/ld.texi > >> >+++ b/ld/ld.texi > >> >@@ -569,6 +569,24 @@ Note that this option is specific to ELF targeted ports. PE targets > >> > support a similar function to export all symbols from a DLL or EXE; see > >> > the description of @samp{--export-all-symbols} below. > >> > > >> >+@kindex --export-dynamic-symbol=@var{glob} > >> >+@cindex export dynamic symbol > >> >+@item --export-dynamic-symbol=@var{glob} > >> >+When creating a dynamically linked executable, symbols matching > >> >+@var{glob} will be added to the dynamic symbol table. When creating a > >> >+shared library, references to symbols matching @var{glob} will not be > >> >+bound to the definitions within the shared library. This option is a > >> >+no-op when creating a shared library and @samp{-Bsymbolic} or > >> >+@samp{--dynamic-list} are not specified. This option is only meaningful > >> >+on ELF platforms which support shared libraries. > >> > >> Is --export-dynamic-symbol still effective for -shared? > >> I think either way is ok. > > > >Yes. > > > >> >+@kindex --export-dynamic-symbol-list=@var{file} > >> >+@cindex export dynamic symbol list > >> >+@item --export-dynamic-symbol-list=@var{file} > >> >+Specify a @samp{--export-dynamic-symbol} for each pattern in the file. > >> >+The format of the file is the same as the version node without > >> >+scope and node name. See @ref{VERSION} for more information. > >> >+ > >> > @ifclear SingleFormat > >> > @cindex big-endian objects > >> > @cindex endianness > >> >diff --git a/ld/ldgram.y b/ld/ldgram.y > >> >index df5c035c03..36845c4c30 100644 > >> >--- a/ld/ldgram.y > >> >+++ b/ld/ldgram.y > >> >@@ -1313,7 +1313,7 @@ dynamic_list_node: > >> > dynamic_list_tag: > >> > vers_defns ';' > >> > { > >> >- lang_append_dynamic_list ($1); > >> >+ lang_append_dynamic_list (current_dynamic_list_p, $1); > >> > } > >> > ; > >> > > >> >diff --git a/ld/ldlang.c b/ld/ldlang.c > >> >index 3d653d460d..14a6a577d2 100644 > >> >--- a/ld/ldlang.c > >> >+++ b/ld/ldlang.c > >> >@@ -118,6 +118,7 @@ lang_statement_list_type file_chain = { NULL, NULL }; > >> > lang_statement_union). */ > >> > lang_statement_list_type input_file_chain; > >> > static const char *current_input_file; > >> >+struct bfd_elf_dynamic_list **current_dynamic_list_p; > >> > struct bfd_sym_chain entry_symbol = { NULL, NULL }; > >> > const char *entry_section = ".text"; > >> > struct lang_input_statement_flags input_flags; > >> >@@ -9324,15 +9325,16 @@ lang_add_unique (const char *name) > >> > /* Append the list of dynamic symbols to the existing one. */ > >> > > >> > void > >> >-lang_append_dynamic_list (struct bfd_elf_version_expr *dynamic) > >> >+lang_append_dynamic_list (struct bfd_elf_dynamic_list **list_p, > >> >+ struct bfd_elf_version_expr *dynamic) > >> > { > >> >- if (link_info.dynamic_list) > >> >+ if (*list_p) > >> > { > >> > struct bfd_elf_version_expr *tail; > >> > for (tail = dynamic; tail->next != NULL; tail = tail->next) > >> > ; > >> >- tail->next = link_info.dynamic_list->head.list; > >> >- link_info.dynamic_list->head.list = dynamic; > >> >+ tail->next = (*list_p)->head.list; > >> >+ (*list_p)->head.list = dynamic; > >> > } > >> > else > >> > { > >> >@@ -9341,7 +9343,7 @@ lang_append_dynamic_list (struct bfd_elf_version_expr *dynamic) > >> > d = (struct bfd_elf_dynamic_list *) xcalloc (1, sizeof *d); > >> > d->head.list = dynamic; > >> > d->match = lang_vers_match; > >> >- link_info.dynamic_list = d; > >> >+ *list_p = d; > >> > } > >> > } > >> > > >> >@@ -9363,7 +9365,7 @@ lang_append_dynamic_list_cpp_typeinfo (void) > >> > dynamic = lang_new_vers_pattern (dynamic, symbols [i], "C++", > >> > FALSE); > >> > > >> >- lang_append_dynamic_list (dynamic); > >> >+ lang_append_dynamic_list (&link_info.dynamic_list, dynamic); > >> > } > >> > > >> > /* Append the list of C++ operator new and delete dynamic symbols to the > >> >@@ -9384,7 +9386,7 @@ lang_append_dynamic_list_cpp_new (void) > >> > dynamic = lang_new_vers_pattern (dynamic, symbols [i], "C++", > >> > FALSE); > >> > > >> >- lang_append_dynamic_list (dynamic); > >> >+ lang_append_dynamic_list (&link_info.dynamic_list, dynamic); > >> > } > >> > > >> > /* Scan a space and/or comma separated string of features. */ > >> >diff --git a/ld/ldlang.h b/ld/ldlang.h > >> >index 3018c3e2ba..529ccd1585 100644 > >> >--- a/ld/ldlang.h > >> >+++ b/ld/ldlang.h > >> >@@ -513,6 +513,8 @@ extern bfd_boolean entry_from_cmdline; > >> > extern lang_statement_list_type file_chain; > >> > extern lang_statement_list_type input_file_chain; > >> > > >> >+extern struct bfd_elf_dynamic_list **current_dynamic_list_p; > >> >+ > >> > extern int lang_statement_iteration; > >> > extern struct asneeded_minfo **asneeded_list_tail; > >> > > >> >@@ -673,7 +675,8 @@ extern struct bfd_elf_version_deps *lang_add_vers_depend > >> > (struct bfd_elf_version_deps *, const char *); > >> > extern void lang_register_vers_node > >> > (const char *, struct bfd_elf_version_tree *, struct bfd_elf_version_deps *); > >> >-extern void lang_append_dynamic_list (struct bfd_elf_version_expr *); > >> >+extern void lang_append_dynamic_list (struct bfd_elf_dynamic_list **, > >> >+ struct bfd_elf_version_expr *); > >> > extern void lang_append_dynamic_list_cpp_typeinfo (void); > >> > extern void lang_append_dynamic_list_cpp_new (void); > >> > extern void lang_add_unique > >> >diff --git a/ld/ldlex.h b/ld/ldlex.h > >> >index 22b928d2d9..2c8d043a09 100644 > >> >--- a/ld/ldlex.h > >> >+++ b/ld/ldlex.h > >> >@@ -81,6 +81,8 @@ enum option_values > >> > OPTION_DYNAMIC_LIST_CPP_NEW, > >> > OPTION_DYNAMIC_LIST_CPP_TYPEINFO, > >> > OPTION_DYNAMIC_LIST_DATA, > >> >+ OPTION_EXPORT_DYNAMIC_SYMBOL, > >> >+ OPTION_EXPORT_DYNAMIC_SYMBOL_LIST, > >> > OPTION_WARN_COMMON, > >> > OPTION_WARN_CONSTRUCTORS, > >> > OPTION_WARN_FATAL, > >> >diff --git a/ld/lexsup.c b/ld/lexsup.c > >> >index fe9526b527..2bac1631d6 100644 > >> >--- a/ld/lexsup.c > >> >+++ b/ld/lexsup.c > >> >@@ -504,6 +504,10 @@ static const struct ld_option ld_options[] = > >> > '\0', NULL, N_("Use C++ typeinfo dynamic list"), TWO_DASHES }, > >> > { {"dynamic-list", required_argument, NULL, OPTION_DYNAMIC_LIST}, > >> > '\0', N_("FILE"), N_("Read dynamic list"), TWO_DASHES }, > >> >+ { {"export-dynamic-symbol", required_argument, NULL, OPTION_EXPORT_DYNAMIC_SYMBOL}, > >> >+ '\0', N_("SYMBOL"), N_("Export the specified symbol"), EXACTLY_TWO_DASHES }, > >> >+ { {"export-dynamic-symbol-list", required_argument, NULL, OPTION_EXPORT_DYNAMIC_SYMBOL_LIST}, > >> >+ '\0', N_("FILE"), N_("Read export dynamic symbol list"), EXACTLY_TWO_DASHES }, > >> > { {"warn-common", no_argument, NULL, OPTION_WARN_COMMON}, > >> > '\0', NULL, N_("Warn about duplicate common symbols"), TWO_DASHES }, > >> > { {"warn-constructors", no_argument, NULL, OPTION_WARN_CONSTRUCTORS}, > >> >@@ -581,6 +585,7 @@ parse_args (unsigned argc, char **argv) > >> > dynamic_list_data, > >> > dynamic_list > >> > } opt_dynamic_list = dynamic_list_unset; > >> >+ struct bfd_elf_dynamic_list *export_list = NULL; > >> > > >> > shortopts = (char *) xmalloc (OPTION_COUNT * 3 + 2); > >> > longopts = (struct option *) > >> >@@ -1418,6 +1423,7 @@ parse_args (unsigned argc, char **argv) > >> > ldfile_open_command_file (optarg); > >> > saved_script_handle = hold_script_handle; > >> > parser_input = input_dynamic_list; > >> >+ current_dynamic_list_p = &link_info.dynamic_list; > >> > yyparse (); > >> > } > >> > if (opt_dynamic_list != dynamic_list_data) > >> >@@ -1425,6 +1431,29 @@ parse_args (unsigned argc, char **argv) > >> > if (opt_symbolic == symbolic) > >> > opt_symbolic = symbolic_unset; > >> > break; > >> >+ case OPTION_EXPORT_DYNAMIC_SYMBOL: > >> >+ { > >> >+ struct bfd_elf_version_expr *expr > >> >+ = lang_new_vers_pattern (NULL, xstrdup (optarg), NULL, > >> >+ FALSE); > >> >+ lang_append_dynamic_list (&export_list, expr); > >> >+ } > >> >+ break; > >> >+ case OPTION_EXPORT_DYNAMIC_SYMBOL_LIST: > >> >+ /* This option indicates a small script that only specifies > >> >+ an export list. Read it, but don't assume that we've > >> >+ seen a linker script. */ > >> >+ { > >> >+ FILE *hold_script_handle; > >> >+ > >> >+ hold_script_handle = saved_script_handle; > >> >+ ldfile_open_command_file (optarg); > >> >+ saved_script_handle = hold_script_handle; > >> >+ parser_input = input_dynamic_list; > >> >+ current_dynamic_list_p = &export_list; > >> >+ yyparse (); > >> >+ } > >> >+ break; > >> > case OPTION_WARN_COMMON: > >> > config.warn_common = TRUE; > >> > break; > >> >@@ -1632,6 +1661,52 @@ parse_args (unsigned argc, char **argv) > >> > && command_line.check_section_addresses < 0) > >> > command_line.check_section_addresses = 0; > >> > > >> >+ if (export_list && !bfd_link_relocatable (&link_info)) > >> >+ { > >> >+ struct bfd_elf_version_expr *head = export_list->head.list; > >> >+ struct bfd_elf_version_expr *next; > >> >+ > >> >+ /* For --export-dynamic-symbol[-list]: > >> >+ 1. When building executable, treat like --dynamic-list. > >> >+ 2. When building shared object: > >> >+ a. If -Bsymbolic or --dynamic-list are used, treat like > >> >+ --dynamic-list. > >> >+ b. Otherwise, ignored. > >> >+ */ > >> >+ bfd_boolean kept = (bfd_link_executable (&link_info) > >> >+ || opt_symbolic != symbolic_unset > >> >+ || opt_dynamic_list != dynamic_list_unset); > >> >+ > >> >+ if (kept) > >> >+ { > >> >+ /* Append the export list to link_info.dynamic_list. */ > >> >+ if (link_info.dynamic_list) > >> >+ { > >> >+ for (next = head; next->next != NULL; next = next->next) > >> >+ ; > >> >+ next->next = link_info.dynamic_list->head.list; > >> >+ link_info.dynamic_list->head.list = head; > >> >+ } > >> >+ else > >> >+ link_info.dynamic_list = export_list; > >> >+ > >> >+ if (opt_dynamic_list != dynamic_list_data) > >> >+ opt_dynamic_list = dynamic_list; > >> >+ if (opt_symbolic == symbolic) > >> >+ opt_symbolic = symbolic_unset; > >> > >> The interaction with -Bsymbolic appears to be more complex now. > >> I think users will pretty much avoid the combination of -Bsymbolic and > >> (--dynamic-list or --export-dynamic-symbol or --export-dynamic-symbol-list). > >> > >> So I beg for a re-consideration of > >> https://sourceware.org/bugzilla/show_bug.cgi?id=26018 > >> https://sourceware.org/pipermail/binutils/2020-May/111223.html > >> > > > >Here is the updated patch on top of > > > >https://sourceware.org/pipermail/binutils/2020-May/111228.html > > Thanks for PATCH v3. LGTM. > > I have verified the semantics of new tests dl2d ~ dl2k. The updated patch to adjust ld-dynamic/export-dynamic-symbol.s for all ELF targets: diff --git a/ld/testsuite/ld-dynamic/export-dynamic-symbol.s b/ld/testsuite/ld-dynamic/export-dynamic-symbol.s index 4b1b8ebd5c..c55da536c5 100644 --- a/ld/testsuite/ld-dynamic/export-dynamic-symbol.s +++ b/ld/testsuite/ld-dynamic/export-dynamic-symbol.s @@ -1,6 +1,14 @@ .text + .global start /* Used by SH targets. */ +start: .global _start _start: + .global __start +__start: + .global main /* Used by HPPA targets. */ +main: + .globl _main /* Used by LynxOS targets. */ +_main: .word 0 .section .text.1, "ax" -- H.J.