>> The --strip-all case is out of question, but my concern is primarily >> with the combination of --strip-symbol/--strip-symbols and -w, but to >> some degree also with the plain use of --strip-symbol/--strip-symbols: >> When trying to cut down the number of symbols in the linux kernel >> (subject to kallsyms lookup) I'm trying to eliminate all non-text >> symbols. Finding them is not a problem, but filtering out those used in >> relocations is, which is why I'd want objcopy to do this for me. Since >> I'm of the general opinion that --strip-symbol for symbols used in >> relocations for non-discarded sections (which I would hope already don't >> get the BSF_KEEP flag set) will result in a broken output file, I'd like >> to make objcopy smart enough to deal with that situation (possibly >> through a new option --keep-needed or --force-strip-needed, depending on >> what the desirable default would be and whether keeping the current >> behavior is a requirement). > >OK - I see your point. My original thinking was that if the user had >specified --strip-symbol=foo on the objcopy command line then that meant >that they definitely wanted "foo" stripped out, even if it was used in a >reloc, and that they knew what they were doing. > >Given that we are dealing with the binutils here, where you are allowed >to shoot yourself in the foot if you do not know what you are doing, I >think that this behaviour of the --strip-symbol switch should be >retained. I would have no objections however to a patch which added >another switch, say --strip-unused-symbol=<>, or indeed the >--keep-needed switch you suggested, in order to provide a safer >environment for stripping symbols. So I chose the more fine-grained method with --strip-unneeded-symbol[s]. Built and tested on i686-pc-linux-gnu. Jan binutils/ 2004-12-15 Jan Beulich * doc/binutils.texi: Document --strip-unneeded-symbol and --strip-unneeded-symbols. * objcopy.c (strip_unneeded_list): New. (enum command_line_switch): Add OPTION_STRIP_UNNEEDED_SYMBOL and OPTION_STRIP_UNNEEDED_SYMBOLS. (copy_options): Add --strip-unneeded-symbol and --strip-unneeded-symbols. (copy_usage): Likewise. (filter_symbols): Suppress copying of symbol if in strip_unneeded_list and the symbol is not needed. (copy_main): Handle OPTION_STRIP_UNNEEDED_SYMBOL and OPTION_STRIP_UNNEEDED_SYMBOLS. --- /home/jbeulich/src/binutils/mainline/2004-12-03.13.35/binutils/doc/binutils.texi 2004-11-18 15:05:13.000000000 +0100 +++ 2004-12-03.13.35/binutils/doc/binutils.texi 2004-12-15 16:35:20.514605416 +0100 @@ -947,6 +947,7 @@ objcopy [@option{-F} @var{bfdname}|@opti [@option{-g}|@option{--strip-debug}] [@option{-K} @var{symbolname}|@option{--keep-symbol=}@var{symbolname}] [@option{-N} @var{symbolname}|@option{--strip-symbol=}@var{symbolname}] + [@option{--strip-unneeded-symbol=}@var{symbolname}] [@option{-G} @var{symbolname}|@option{--keep-global-symbol=}@var{symbolname}] [@option{-L} @var{symbolname}|@option{--localize-symbol=}@var{symbolname}] [@option{-W} @var{symbolname}|@option{--weaken-symbol=}@var{symbolname}] @@ -978,6 +979,7 @@ objcopy [@option{-F} @var{bfdname}|@opti [@option{--weaken}] [@option{--keep-symbols=}@var{filename}] [@option{--strip-symbols=}@var{filename}] + [@option{--strip-unneeded-symbols=}@var{filename}] [@option{--keep-global-symbols=}@var{filename}] [@option{--localize-symbols=}@var{filename}] [@option{--weaken-symbols=}@var{filename}] @@ -1106,6 +1108,10 @@ be given more than once. Do not copy symbol @var{symbolname} from the source file. This option may be given more than once. +@item --strip-unneeded-symbol=@var{symbolname} +Do not copy symbol @var{symbolname} from the source file unless it is needed +by a relocation. This option may be given more than once. + @item -G @var{symbolname} @itemx --keep-global-symbol=@var{symbolname} Keep only symbol @var{symbolname} global. Make all other symbols local @@ -1347,6 +1353,12 @@ Apply @option{--strip-symbol} option to name per line. Line comments may be introduced by the hash character. This option may be given more than once. +@item --strip-unneeded-symbols=@var{filename} +Apply @option{--strip-unneeded-symbol} option to each symbol listed in +the file @var{filename}. @var{filename} is simply a flat file, with one +symbol name per line. Line comments may be introduced by the hash +character. This option may be given more than once. + @item --keep-global-symbols=@var{filename} Apply @option{--keep-global-symbol} option to each symbol listed in the file @var{filename}. @var{filename} is simply a flat file, with one --- /home/jbeulich/src/binutils/mainline/2004-12-03.13.35/binutils/objcopy.c 2004-11-02 17:16:02.000000000 +0100 +++ 2004-12-03.13.35/binutils/objcopy.c 2004-12-15 16:26:32.097936960 +0100 @@ -192,6 +192,7 @@ static bfd_boolean wildcard = FALSE; /* List of symbols to strip, keep, localize, keep-global, weaken, or redefine. */ static struct symlist *strip_specific_list = NULL; +static struct symlist *strip_unneeded_list = NULL; static struct symlist *keep_specific_list = NULL; static struct symlist *localize_specific_list = NULL; static struct symlist *keepglobal_specific_list = NULL; @@ -231,6 +232,8 @@ enum command_line_switch OPTION_SREC_LEN, OPTION_SREC_FORCES3, OPTION_STRIP_SYMBOLS, + OPTION_STRIP_UNNEEDED_SYMBOL, + OPTION_STRIP_UNNEEDED_SYMBOLS, OPTION_KEEP_SYMBOLS, OPTION_LOCALIZE_SYMBOLS, OPTION_KEEPGLOBAL_SYMBOLS, @@ -340,6 +343,8 @@ static struct option copy_options[] = {"strip-all", no_argument, 0, 'S'}, {"strip-debug", no_argument, 0, 'g'}, {"strip-unneeded", no_argument, 0, OPTION_STRIP_UNNEEDED}, + {"strip-unneeded-symbol", required_argument, 0, OPTION_STRIP_UNNEEDED_SYMBOL}, + {"strip-unneeded-symbols", required_argument, 0, OPTION_STRIP_UNNEEDED_SYMBOLS}, {"strip-symbol", required_argument, 0, 'N'}, {"strip-symbols", required_argument, 0, OPTION_STRIP_SYMBOLS}, {"target", required_argument, 0, 'F'}, @@ -405,6 +410,9 @@ copy_usage (FILE *stream, int exit_statu -g --strip-debug Remove all debugging symbols & sections\n\ --strip-unneeded Remove all symbols not needed by relocations\n\ -N --strip-symbol Do not copy symbol \n\ + --strip-unneeded-symbol \n\ + Do not copy symbol unless needed by\n\ + relocations\n\ --only-keep-debug Strip everything but the debug information\n\ -K --keep-symbol Only copy symbol \n\ -L --localize-symbol Force symbol to be marked as a local\n\ @@ -443,6 +451,9 @@ copy_usage (FILE *stream, int exit_statu --srec-len Restrict the length of generated Srecords\n\ --srec-forceS3 Restrict the type of generated Srecords to S3\n\ --strip-symbols -N for all symbols listed in \n\ + --strip-unneeded-symbols \n\ + --strip-unneeded-symbol for all symbols listed\n\ + in \n\ --keep-symbols -K for all symbols listed in \n\ --localize-symbols -L for all symbols listed in \n\ --keep-global-symbols -G for all symbols listed in \n\ @@ -903,6 +914,10 @@ filter_symbols (bfd *abfd, bfd *obfd, as if (keep && is_specified_symbol (name, strip_specific_list)) keep = 0; + if (keep + && !(flags & BSF_KEEP) + && is_specified_symbol (name, strip_unneeded_list)) + keep = 0; if (!keep && is_specified_symbol (name, keep_specific_list)) keep = 1; if (keep && is_strip_section (abfd, bfd_get_section (sym))) @@ -2525,6 +2540,10 @@ copy_main (int argc, char *argv[]) add_specific_symbol (optarg, &strip_specific_list); break; + case OPTION_STRIP_UNNEEDED_SYMBOL: + add_specific_symbol (optarg, &strip_unneeded_list); + break; + case 'L': add_specific_symbol (optarg, &localize_specific_list); break; @@ -2858,6 +2877,10 @@ copy_main (int argc, char *argv[]) add_specific_symbols (optarg, &strip_specific_list); break; + case OPTION_STRIP_UNNEEDED_SYMBOLS: + add_specific_symbols (optarg, &strip_unneeded_list); + break; + case OPTION_KEEP_SYMBOLS: add_specific_symbols (optarg, &keep_specific_list); break;