yuezonghe | 824eb0c | 2024-06-27 02:32:26 -0700 | [diff] [blame] | 1 | /* Support macros for making weak and strong aliases for symbols, |
| 2 | and for using symbol sets and linker warnings with GNU ld. |
| 3 | Copyright (C) 1995-1998,2000-2003,2004,2005,2006 |
| 4 | Free Software Foundation, Inc. |
| 5 | This file is part of the GNU C Library. |
| 6 | |
| 7 | The GNU C Library is free software; you can redistribute it and/or |
| 8 | modify it under the terms of the GNU Lesser General Public |
| 9 | License as published by the Free Software Foundation; either |
| 10 | version 2.1 of the License, or (at your option) any later version. |
| 11 | |
| 12 | The GNU C Library is distributed in the hope that it will be useful, |
| 13 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 15 | Lesser General Public License for more details. |
| 16 | |
| 17 | You should have received a copy of the GNU Lesser General Public |
| 18 | License along with the GNU C Library; if not, write to the Free |
| 19 | Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
| 20 | 02111-1307 USA. */ |
| 21 | |
| 22 | #ifndef _LIBC_SYMBOLS_H |
| 23 | #define _LIBC_SYMBOLS_H 1 |
| 24 | |
| 25 | /* This is defined for the compilation of all C library code. features.h |
| 26 | tests this to avoid inclusion of stubs.h while compiling the library, |
| 27 | before stubs.h has been generated. Some library code that is shared |
| 28 | with other packages also tests this symbol to see if it is being |
| 29 | compiled as part of the C library. We must define this before including |
| 30 | config.h, because it makes some definitions conditional on whether libc |
| 31 | itself is being compiled, or just some generator program. */ |
| 32 | #define _LIBC 1 |
| 33 | |
| 34 | |
| 35 | /* This file's macros are included implicitly in the compilation of every |
| 36 | file in the C library by -imacros. |
| 37 | |
| 38 | We include uClibc_arch_features.h which is defined by arch devs. |
| 39 | It should define for us the following symbols: |
| 40 | |
| 41 | * HAVE_ASM_SET_DIRECTIVE if we have `.set B, A' instead of `A = B'. |
| 42 | * ASM_GLOBAL_DIRECTIVE with `.globl' or `.global'. |
| 43 | * ASM_TYPE_DIRECTIVE_PREFIX with `@' or `#' or whatever for .type, |
| 44 | or leave it undefined if there is no .type directive. |
| 45 | * HAVE_ELF if using ELF, which supports weak symbols using `.weak'. |
| 46 | * HAVE_ASM_WEAK_DIRECTIVE if we have weak symbols using `.weak'. |
| 47 | * HAVE_ASM_WEAKEXT_DIRECTIVE if we have weak symbols using `.weakext'. |
| 48 | |
| 49 | */ |
| 50 | |
| 51 | #include <bits/uClibc_arch_features.h> |
| 52 | |
| 53 | /* Enable declarations of GNU extensions, since we are compiling them. */ |
| 54 | #define _GNU_SOURCE 1 |
| 55 | |
| 56 | /* Prepare for the case that `__builtin_expect' is not available. */ |
| 57 | #if defined __GNUC__ && __GNUC__ == 2 && __GNUC_MINOR__ < 96 |
| 58 | # define __builtin_expect(x, expected_value) (x) |
| 59 | #endif |
| 60 | #ifndef likely |
| 61 | # define likely(x) __builtin_expect((!!(x)),1) |
| 62 | #endif |
| 63 | #ifndef unlikely |
| 64 | # define unlikely(x) __builtin_expect((!!(x)),0) |
| 65 | #endif |
| 66 | #if defined __GNUC__ && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3)) |
| 67 | # ifndef __cold |
| 68 | # define __cold __attribute__ ((__cold__)) |
| 69 | # endif |
| 70 | # ifndef __hot |
| 71 | # define __hot __attribute__ ((__hot__)) |
| 72 | # endif |
| 73 | #else |
| 74 | # ifndef __cold |
| 75 | # define __cold |
| 76 | # endif |
| 77 | # ifndef __hot |
| 78 | # define __hot |
| 79 | # endif |
| 80 | #endif |
| 81 | #ifndef __LINUX_COMPILER_H |
| 82 | # define __LINUX_COMPILER_H |
| 83 | #endif |
| 84 | #ifndef __cast__ |
| 85 | # define __cast__(_to) |
| 86 | #endif |
| 87 | |
| 88 | #if defined __GNUC__ && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 4)) |
| 89 | # define attribute_optimize(x) __attribute__ ((optimize(x))) |
| 90 | #else |
| 91 | # define attribute_optimize(x) |
| 92 | #endif |
| 93 | |
| 94 | #define attribute_unused __attribute__ ((unused)) |
| 95 | |
| 96 | #if defined __GNUC__ || defined __ICC |
| 97 | # define attribute_noreturn __attribute__ ((__noreturn__)) |
| 98 | #else |
| 99 | # define attribute_noreturn |
| 100 | #endif |
| 101 | |
| 102 | #define libc_freeres_ptr(decl) \ |
| 103 | __make_section_unallocated ("__libc_freeres_ptrs, \"aw\", %nobits") \ |
| 104 | decl __attribute__ ((section ("__libc_freeres_ptrs" __sec_comment))) |
| 105 | #define __libc_freeres_fn_section \ |
| 106 | __attribute__ ((section ("__libc_freeres_fn"))) |
| 107 | |
| 108 | #ifndef NOT_IN_libc |
| 109 | # define IS_IN_libc 1 |
| 110 | #endif |
| 111 | |
| 112 | /* Indirect stringification. Doing two levels allows |
| 113 | * the parameter to be a macro itself. |
| 114 | */ |
| 115 | #define __stringify_1(x) #x |
| 116 | #define __stringify(x) __stringify_1(x) |
| 117 | |
| 118 | #ifdef __UCLIBC_HAVE_ASM_SET_DIRECTIVE__ |
| 119 | # define HAVE_ASM_SET_DIRECTIVE |
| 120 | #else |
| 121 | # undef HAVE_ASM_SET_DIRECTIVE |
| 122 | #endif |
| 123 | |
| 124 | #ifdef __UCLIBC_ASM_GLOBAL_DIRECTIVE__ |
| 125 | # define ASM_GLOBAL_DIRECTIVE __UCLIBC_ASM_GLOBAL_DIRECTIVE__ |
| 126 | #else |
| 127 | # define ASM_GLOBAL_DIRECTIVE .global |
| 128 | #endif |
| 129 | |
| 130 | #ifdef __UCLIBC_HAVE_ASM_WEAK_DIRECTIVE__ |
| 131 | # define HAVE_ASM_WEAK_DIRECTIVE |
| 132 | #else |
| 133 | # undef HAVE_ASM_WEAK_DIRECTIVE |
| 134 | #endif |
| 135 | |
| 136 | #ifdef __UCLIBC_HAVE_ASM_WEAKEXT_DIRECTIVE__ |
| 137 | # define HAVE_ASM_WEAKEXT_DIRECTIVE |
| 138 | #else |
| 139 | # undef HAVE_ASM_WEAKEXT_DIRECTIVE |
| 140 | #endif |
| 141 | |
| 142 | #ifdef __UCLIBC_HAVE_ASM_GLOBAL_DOT_NAME__ |
| 143 | # define HAVE_ASM_GLOBAL_DOT_NAME |
| 144 | #else |
| 145 | # undef HAVE_ASM_GLOBAL_DOT_NAME |
| 146 | #endif |
| 147 | |
| 148 | #ifdef __UCLIBC_HAVE_ASM_CFI_DIRECTIVES__ |
| 149 | # define HAVE_ASM_CFI_DIRECTIVES |
| 150 | #else |
| 151 | # undef HAVE_ASM_CFI_DIRECTIVES |
| 152 | #endif |
| 153 | |
| 154 | #if defined HAVE_ASM_WEAK_DIRECTIVE || defined HAVE_ASM_WEAKEXT_DIRECTIVE |
| 155 | # define HAVE_WEAK_SYMBOLS |
| 156 | #endif |
| 157 | |
| 158 | #undef C_SYMBOL_NAME |
| 159 | #ifndef C_SYMBOL_NAME |
| 160 | # ifndef __UCLIBC_UNDERSCORES__ |
| 161 | # define C_SYMBOL_NAME(name) name |
| 162 | # else |
| 163 | # define C_SYMBOL_NAME(name) _##name |
| 164 | # endif |
| 165 | #endif |
| 166 | |
| 167 | #ifdef __UCLIBC_ASM_LINE_SEP__ |
| 168 | # define ASM_LINE_SEP __UCLIBC_ASM_LINE_SEP__ |
| 169 | #else |
| 170 | # define ASM_LINE_SEP ; |
| 171 | #endif |
| 172 | |
| 173 | #ifdef HAVE_ASM_GLOBAL_DOT_NAME |
| 174 | # ifndef C_SYMBOL_DOT_NAME |
| 175 | # if defined __GNUC__ && defined __GNUC_MINOR__ \ |
| 176 | && (__GNUC__ << 16) + __GNUC_MINOR__ >= (3 << 16) + 1 |
| 177 | # define C_SYMBOL_DOT_NAME(name) .name |
| 178 | # else |
| 179 | # define C_SYMBOL_DOT_NAME(name) .##name |
| 180 | # endif |
| 181 | # endif |
| 182 | #endif |
| 183 | |
| 184 | #ifndef __ASSEMBLER__ |
| 185 | /* GCC understands weak symbols and aliases; use its interface where |
| 186 | possible, instead of embedded assembly language. */ |
| 187 | |
| 188 | /* Define ALIASNAME as a strong alias for NAME. */ |
| 189 | # define strong_alias(name, aliasname) _strong_alias(name, aliasname) |
| 190 | # define _strong_alias(name, aliasname) \ |
| 191 | extern __typeof (name) aliasname __attribute__ ((alias (#name))); |
| 192 | /* Same, but does not check for type match. Use sparingly. |
| 193 | Example: strong_alias(stat,stat64) may fail, this one works: */ |
| 194 | # define strong_alias_untyped(name, aliasname) \ |
| 195 | _strong_alias_untyped(name, aliasname) |
| 196 | # define _strong_alias_untyped(name, aliasname) \ |
| 197 | extern __typeof (aliasname) aliasname __attribute__ ((alias (#name))); |
| 198 | |
| 199 | /* This comes between the return type and function name in |
| 200 | a function definition to make that definition weak. */ |
| 201 | # define weak_function __attribute__ ((weak)) |
| 202 | # define weak_const_function __attribute__ ((weak, __const__)) |
| 203 | |
| 204 | # ifdef HAVE_WEAK_SYMBOLS |
| 205 | |
| 206 | /* Define ALIASNAME as a weak alias for NAME. |
| 207 | If weak aliases are not available, this defines a strong alias. */ |
| 208 | # define weak_alias(name, aliasname) _weak_alias (name, aliasname) |
| 209 | # define _weak_alias(name, aliasname) \ |
| 210 | extern __typeof (name) aliasname __attribute__ ((weak, alias (#name))); |
| 211 | |
| 212 | /* Declare SYMBOL as weak undefined symbol (resolved to 0 if not defined). */ |
| 213 | # define weak_extern(symbol) _weak_extern (weak symbol) |
| 214 | # define _weak_extern(expr) _Pragma (#expr) |
| 215 | |
| 216 | # else |
| 217 | |
| 218 | # define weak_alias(name, aliasname) strong_alias(name, aliasname) |
| 219 | # define weak_extern(symbol) /* Nothing. */ |
| 220 | |
| 221 | # endif |
| 222 | |
| 223 | #else /* __ASSEMBLER__ */ |
| 224 | |
| 225 | # ifdef HAVE_ASM_SET_DIRECTIVE |
| 226 | # ifdef HAVE_ASM_GLOBAL_DOT_NAME |
| 227 | # define strong_alias(original, alias) \ |
| 228 | ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME(alias) ASM_LINE_SEP \ |
| 229 | .set C_SYMBOL_NAME(alias),C_SYMBOL_NAME(original) ASM_LINE_SEP \ |
| 230 | ASM_GLOBAL_DIRECTIVE C_SYMBOL_DOT_NAME(alias) ASM_LINE_SEP \ |
| 231 | .set C_SYMBOL_DOT_NAME(alias),C_SYMBOL_DOT_NAME(original) |
| 232 | # define strong_data_alias(original, alias) \ |
| 233 | ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME(alias) ASM_LINE_SEP \ |
| 234 | .set C_SYMBOL_NAME(alias),C_SYMBOL_NAME(original) |
| 235 | # else |
| 236 | # define strong_alias(original, alias) \ |
| 237 | ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME(alias) ASM_LINE_SEP \ |
| 238 | .set C_SYMBOL_NAME(alias),C_SYMBOL_NAME(original) |
| 239 | # define strong_data_alias(original, alias) strong_alias(original, alias) |
| 240 | # endif |
| 241 | # else |
| 242 | # ifdef HAVE_ASM_GLOBAL_DOT_NAME |
| 243 | # define strong_alias(original, alias) \ |
| 244 | ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME(alias) ASM_LINE_SEP \ |
| 245 | C_SYMBOL_NAME(alias) = C_SYMBOL_NAME(original) ASM_LINE_SEP \ |
| 246 | ASM_GLOBAL_DIRECTIVE C_SYMBOL_DOT_NAME(alias) ASM_LINE_SEP \ |
| 247 | C_SYMBOL_DOT_NAME(alias) = C_SYMBOL_DOT_NAME(original) |
| 248 | # define strong_data_alias(original, alias) \ |
| 249 | ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME(alias) ASM_LINE_SEP \ |
| 250 | C_SYMBOL_NAME(alias) = C_SYMBOL_NAME(original) |
| 251 | # else |
| 252 | # define strong_alias(original, alias) \ |
| 253 | ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME(alias) ASM_LINE_SEP \ |
| 254 | C_SYMBOL_NAME(alias) = C_SYMBOL_NAME(original) |
| 255 | # define strong_data_alias(original, alias) strong_alias(original, alias) |
| 256 | # endif |
| 257 | # endif |
| 258 | |
| 259 | # ifdef HAVE_WEAK_SYMBOLS |
| 260 | # ifdef HAVE_ASM_WEAKEXT_DIRECTIVE |
| 261 | # ifdef HAVE_ASM_GLOBAL_DOT_NAME |
| 262 | # define weak_alias(original, alias) \ |
| 263 | .weakext C_SYMBOL_NAME(alias),C_SYMBOL_NAME(original) ASM_LINE_SEP \ |
| 264 | .weakext C_SYMBOL_DOT_NAME(alias),C_SYMBOL_DOT_NAME(original) |
| 265 | # else |
| 266 | # define weak_alias(original, alias) \ |
| 267 | .weakext C_SYMBOL_NAME(alias),C_SYMBOL_NAME(original) |
| 268 | # endif |
| 269 | # define weak_extern(symbol) \ |
| 270 | .weakext C_SYMBOL_NAME(symbol) |
| 271 | |
| 272 | # else /* ! HAVE_ASM_WEAKEXT_DIRECTIVE */ |
| 273 | |
| 274 | # ifdef HAVE_ASM_SET_DIRECTIVE |
| 275 | # ifdef HAVE_ASM_GLOBAL_DOT_NAME |
| 276 | # define weak_alias(original, alias) \ |
| 277 | .weak C_SYMBOL_NAME(alias) ASM_LINE_SEP \ |
| 278 | .set C_SYMBOL_NAME(alias),C_SYMBOL_NAME(original) ASM_LINE_SEP \ |
| 279 | .weak C_SYMBOL_DOT_NAME(alias) ASM_LINE_SEP \ |
| 280 | .set C_SYMBOL_DOT_NAME(alias),C_SYMBOL_DOT_NAME(original) |
| 281 | # else |
| 282 | # define weak_alias(original, alias) \ |
| 283 | .weak C_SYMBOL_NAME(alias) ASM_LINE_SEP \ |
| 284 | .set C_SYMBOL_NAME(alias),C_SYMBOL_NAME(original) |
| 285 | # endif |
| 286 | # else /* ! HAVE_ASM_SET_DIRECTIVE */ |
| 287 | # ifdef HAVE_ASM_GLOBAL_DOT_NAME |
| 288 | # define weak_alias(original, alias) \ |
| 289 | .weak C_SYMBOL_NAME(alias) ASM_LINE_SEP \ |
| 290 | C_SYMBOL_NAME(alias) = C_SYMBOL_NAME(original) ASM_LINE_SEP \ |
| 291 | .weak C_SYMBOL_DOT_NAME(alias) ASM_LINE_SEP \ |
| 292 | C_SYMBOL_DOT_NAME(alias) = C_SYMBOL_DOT_NAME(original) |
| 293 | # else |
| 294 | # define weak_alias(original, alias) \ |
| 295 | .weak C_SYMBOL_NAME(alias) ASM_LINE_SEP \ |
| 296 | C_SYMBOL_NAME(alias) = C_SYMBOL_NAME(original) |
| 297 | # endif |
| 298 | # endif |
| 299 | # define weak_extern(symbol) \ |
| 300 | .weak C_SYMBOL_NAME(symbol) |
| 301 | |
| 302 | # endif /* ! HAVE_ASM_WEAKEXT_DIRECTIVE */ |
| 303 | |
| 304 | # else /* ! HAVE_WEAK_SYMBOLS */ |
| 305 | |
| 306 | # define weak_alias(original, alias) strong_alias(original, alias) |
| 307 | # define weak_extern(symbol) /* Nothing */ |
| 308 | # endif /* ! HAVE_WEAK_SYMBOLS */ |
| 309 | |
| 310 | #endif /* __ASSEMBLER__ */ |
| 311 | |
| 312 | |
| 313 | /* On some platforms we can make internal function calls (i.e., calls of |
| 314 | functions not exported) a bit faster by using a different calling |
| 315 | convention. */ |
| 316 | #ifndef internal_function |
| 317 | # define internal_function /* empty */ |
| 318 | #endif |
| 319 | |
| 320 | |
| 321 | /* We want the .gnu.warning.SYMBOL section to be unallocated. */ |
| 322 | #define __make_section_unallocated(section_string) \ |
| 323 | __asm__ (".section " section_string "\n\t.previous"); |
| 324 | |
| 325 | |
| 326 | /* Tacking on "\n#APP\n\t#" to the section name makes gcc put it's bogus |
| 327 | section attributes on what looks like a comment to the assembler. */ |
| 328 | #ifdef __sparc__ /* HAVE_SECTION_QUOTES */ |
| 329 | # define __sec_comment "\"\n#APP\n\t#\"" |
| 330 | #else |
| 331 | # define __sec_comment "\n#APP\n\t#" |
| 332 | #endif |
| 333 | |
| 334 | |
| 335 | /* When a reference to SYMBOL is encountered, the linker will emit a |
| 336 | warning message MSG. */ |
| 337 | #define link_warning(symbol, msg) \ |
| 338 | __make_section_unallocated (".gnu.warning." #symbol) \ |
| 339 | static const char __evoke_link_warning_##symbol[] \ |
| 340 | __attribute__ ((used, section (".gnu.warning." #symbol __sec_comment))) \ |
| 341 | = msg; |
| 342 | |
| 343 | /* Handling on non-exported internal names. We have to do this only |
| 344 | for shared code. */ |
| 345 | #ifdef SHARED |
| 346 | # define INTUSE(name) name##_internal |
| 347 | # define INTDEF(name) strong_alias (name, name##_internal) |
| 348 | # define INTVARDEF(name) _INTVARDEF (name, name##_internal) |
| 349 | # if defined HAVE_VISIBILITY_ATTRIBUTE |
| 350 | # define _INTVARDEF(name, aliasname) \ |
| 351 | extern __typeof (name) aliasname __attribute__ ((alias (#name), \ |
| 352 | visibility ("hidden"))); |
| 353 | # else |
| 354 | # define _INTVARDEF(name, aliasname) \ |
| 355 | extern __typeof (name) aliasname __attribute__ ((alias (#name))); |
| 356 | # endif |
| 357 | # define INTDEF2(name, newname) strong_alias (name, newname##_internal) |
| 358 | # define INTVARDEF2(name, newname) _INTVARDEF (name, newname##_internal) |
| 359 | #else |
| 360 | # define INTUSE(name) name |
| 361 | # define INTDEF(name) |
| 362 | # define INTVARDEF(name) |
| 363 | # define INTDEF2(name, newname) |
| 364 | # define INTVARDEF2(name, newname) |
| 365 | #endif |
| 366 | |
| 367 | |
| 368 | /* The following macros are used for PLT bypassing within libc.so |
| 369 | (and if needed other libraries similarly). |
| 370 | |
| 371 | If calls to foo within libc.so should always go to foo defined in libc.so, |
| 372 | then in include/foo.h you add: |
| 373 | |
| 374 | int foo(int __bar); |
| 375 | libc_hidden_proto(foo) |
| 376 | |
| 377 | line and after the foo function definition: |
| 378 | |
| 379 | int foo(int __bar) { |
| 380 | return __bar; |
| 381 | } |
| 382 | libc_hidden_def(foo) |
| 383 | |
| 384 | or |
| 385 | |
| 386 | int foo(int __bar) { |
| 387 | return __bar; |
| 388 | } |
| 389 | libc_hidden_weak(foo) |
| 390 | |
| 391 | Similarly for global data: if references to foo within libc.so |
| 392 | should always go to foo defined in libc.so, then in include/foo.h: |
| 393 | |
| 394 | extern int foo; |
| 395 | libc_hidden_proto(foo) |
| 396 | |
| 397 | and after foo's definition: |
| 398 | |
| 399 | int foo = INITIAL_FOO_VALUE; |
| 400 | libc_hidden_data_def(foo) |
| 401 | |
| 402 | or |
| 403 | |
| 404 | int foo = INITIAL_FOO_VALUE; |
| 405 | libc_hidden_data_weak(foo) |
| 406 | |
| 407 | If foo is normally just an alias (strong or weak) to some other function, |
| 408 | you should use the normal strong_alias first, then add libc_hidden_def |
| 409 | or libc_hidden_weak: |
| 410 | |
| 411 | int baz(int __bar) { |
| 412 | return __bar; |
| 413 | } |
| 414 | strong_alias(baz, foo) |
| 415 | libc_hidden_weak(foo) |
| 416 | |
| 417 | If the function should be internal to multiple objects, say ld.so and |
| 418 | libc.so, the best way is to use: |
| 419 | |
| 420 | #if !defined NOT_IN_libc || defined IS_IN_rtld |
| 421 | hidden_proto(foo) |
| 422 | #endif |
| 423 | |
| 424 | in include/foo.h and the normal macros at all function definitions |
| 425 | depending on what DSO they belong to. |
| 426 | |
| 427 | If versioned_symbol macro is used to define foo, |
| 428 | libc_hidden_ver macro should be used, as in: |
| 429 | |
| 430 | int __real_foo(int __bar) { |
| 431 | return __bar; |
| 432 | } |
| 433 | versioned_symbol(libc, __real_foo, foo, GLIBC_2_1); |
| 434 | libc_hidden_ver(__real_foo, foo) |
| 435 | */ |
| 436 | |
| 437 | /* uClibc specific (the above comment was copied from glibc): |
| 438 | * |
| 439 | * when ppc64 will be supported, we need changes to support |
| 440 | * strong_data_alias (used by asm hidden_data_def) |
| 441 | * |
| 442 | * no versioning support, hidden[_data]_ver are noop |
| 443 | * |
| 444 | * hidden_def() in asm is _hidden_strong_alias (not strong_alias) |
| 445 | * |
| 446 | * libc_hidden_proto(foo) should be added after declaration |
| 447 | * in the header, or after extern foo... in all source files |
| 448 | * (this is discouraged). |
| 449 | * libc_hidden_def does not hide __GI_foo itself, although the name |
| 450 | * suggests it (hiding is done exclusively by libc_hidden_proto). |
| 451 | |
| 452 | FIXME! - ? |
| 453 | * The reasoning to have it after the header w/ foo's prototype is |
| 454 | * to get first the __REDIRECT from original header and then create |
| 455 | * the __GI_foo alias |
| 456 | |
| 457 | * Hunt for references which still go through PLT (example for x86): |
| 458 | * build shared lib, then disassemble it and search for <xxx@plt>: |
| 459 | * $ objdump -drx libuClibc-*.so >disasm.txt |
| 460 | * $ grep -F '@plt>:' disasm.txt |
| 461 | * |
| 462 | * In uclibc, malloc/free and related functions should be called |
| 463 | * through PLT (making it possible to use alternative malloc), |
| 464 | * and possibly some __pthread_xxx functions can be called through PLT |
| 465 | * (why?). The rest should not use PLT. |
| 466 | */ |
| 467 | |
| 468 | #if (defined __GNUC__ && defined __GNUC_MINOR__ \ |
| 469 | && (( __GNUC__ >= 3 && __GNUC_MINOR__ >= 3) || __GNUC__ >= 4) \ |
| 470 | ) || defined __ICC |
| 471 | # define attribute_hidden __attribute__ ((visibility ("hidden"))) |
| 472 | # define attribute_protected __attribute__ ((visibility ("protected"))) |
| 473 | # define __hidden_proto_hiddenattr(attrs...) __attribute__ ((visibility ("hidden"), ##attrs)) |
| 474 | #else |
| 475 | # define attribute_hidden |
| 476 | # define attribute_protected |
| 477 | # define __hidden_proto_hiddenattr(attrs...) |
| 478 | #endif |
| 479 | |
| 480 | #if /*!defined STATIC &&*/ !defined __BCC__ |
| 481 | |
| 482 | # ifndef __ASSEMBLER__ |
| 483 | # define hidden_proto(name, attrs...) __hidden_proto(name, __GI_##name, ##attrs) |
| 484 | # define __hidden_proto(name, internal, attrs...) \ |
| 485 | extern __typeof (name) name __asm__ (__hidden_asmname (#internal)) \ |
| 486 | __hidden_proto_hiddenattr (attrs); |
| 487 | # define __hidden_asmname(name) __hidden_asmname1 (__USER_LABEL_PREFIX__, name) |
| 488 | # define __hidden_asmname1(prefix, name) __hidden_asmname2(prefix, name) |
| 489 | # define __hidden_asmname2(prefix, name) #prefix name |
| 490 | # define __hidden_ver1(local, internal, name) \ |
| 491 | extern __typeof (name) __EI_##name __asm__(__hidden_asmname (#internal)); \ |
| 492 | extern __typeof (name) __EI_##name __attribute__((alias (__hidden_asmname1 (,#local)))) |
| 493 | # define hidden_ver(local, name) __hidden_ver1(local, __GI_##name, name); |
| 494 | # define hidden_data_ver(local, name) hidden_ver(local, name) |
| 495 | # define hidden_def(name) __hidden_ver1(__GI_##name, name, name); |
| 496 | # define hidden_data_def(name) hidden_def(name) |
| 497 | # define hidden_weak(name) \ |
| 498 | __hidden_ver1(__GI_##name, name, name) __attribute__((weak)); |
| 499 | # define hidden_data_weak(name) hidden_weak(name) |
| 500 | |
| 501 | # else /* __ASSEMBLER__ */ |
| 502 | |
| 503 | # ifdef HAVE_ASM_SET_DIRECTIVE |
| 504 | # ifdef HAVE_ASM_GLOBAL_DOT_NAME |
| 505 | # define _hidden_strong_alias(original, alias) \ |
| 506 | ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME(alias) ASM_LINE_SEP \ |
| 507 | .hidden C_SYMBOL_NAME(alias) ASM_LINE_SEP \ |
| 508 | .set C_SYMBOL_NAME(alias),C_SYMBOL_NAME(original) ASM_LINE_SEP \ |
| 509 | ASM_GLOBAL_DIRECTIVE C_SYMBOL_DOT_NAME(alias) ASM_LINE_SEP \ |
| 510 | .hidden C_SYMBOL_DOT_NAME(alias) ASM_LINE_SEP \ |
| 511 | .set C_SYMBOL_DOT_NAME(alias),C_SYMBOL_DOT_NAME(original) |
| 512 | # else |
| 513 | # define _hidden_strong_alias(original, alias) \ |
| 514 | ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME(alias) ASM_LINE_SEP \ |
| 515 | .hidden C_SYMBOL_NAME(alias) ASM_LINE_SEP \ |
| 516 | .set C_SYMBOL_NAME(alias),C_SYMBOL_NAME(original) |
| 517 | # endif |
| 518 | # else /* dont have .set directive */ |
| 519 | # ifdef HAVE_ASM_GLOBAL_DOT_NAME |
| 520 | # define _hidden_strong_alias(original, alias) \ |
| 521 | ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME(alias) ASM_LINE_SEP \ |
| 522 | .hidden C_SYMBOL_NAME(alias) ASM_LINE_SEP \ |
| 523 | C_SYMBOL_NAME(alias) = C_SYMBOL_NAME(original) ASM_LINE_SEP \ |
| 524 | ASM_GLOBAL_DIRECTIVE C_SYMBOL_DOT_NAME(alias) ASM_LINE_SEP \ |
| 525 | .hidden C_SYMBOL_DOT_NAME(alias) ASM_LINE_SEP \ |
| 526 | C_SYMBOL_DOT_NAME(alias) = C_SYMBOL_DOT_NAME(original) |
| 527 | # else |
| 528 | # define _hidden_strong_alias(original, alias) \ |
| 529 | ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME(alias) ASM_LINE_SEP \ |
| 530 | .hidden C_SYMBOL_NAME(alias) ASM_LINE_SEP \ |
| 531 | C_SYMBOL_NAME(alias) = C_SYMBOL_NAME(original) |
| 532 | # endif |
| 533 | # endif |
| 534 | |
| 535 | # ifdef HAVE_ASM_GLOBAL_DOT_NAME |
| 536 | # define _hidden_weak_alias(original, alias) \ |
| 537 | .hidden C_SYMBOL_NAME(alias) ASM_LINE_SEP \ |
| 538 | .hidden C_SYMBOL_DOT_NAME(alias) ASM_LINE_SEP \ |
| 539 | weak_alias(original, alias) |
| 540 | # else |
| 541 | # define _hidden_weak_alias(original, alias) \ |
| 542 | .hidden C_SYMBOL_NAME(alias) ASM_LINE_SEP \ |
| 543 | weak_alias(original, alias) |
| 544 | # endif |
| 545 | |
| 546 | /* For assembly, we need to do the opposite of what we do in C: |
| 547 | in assembly gcc __REDIRECT stuff is not in place, so functions |
| 548 | are defined by its normal name and we need to create the |
| 549 | __GI_* alias to it, in C __REDIRECT causes the function definition |
| 550 | to use __GI_* name and we need to add alias to the real name. |
| 551 | There is no reason to use hidden_weak over hidden_def in assembly, |
| 552 | but we provide it for consistency with the C usage. |
| 553 | hidden_proto doesn't make sense for assembly but the equivalent |
| 554 | is to call via the HIDDEN_JUMPTARGET macro instead of JUMPTARGET. */ |
| 555 | # define hidden_def(name) _hidden_strong_alias (name, __GI_##name) |
| 556 | # define hidden_weak(name) _hidden_weak_alias (name, __GI_##name) |
| 557 | # define hidden_ver(local, name) strong_alias (local, __GI_##name) |
| 558 | # define hidden_data_def(name) _hidden_strong_alias (name, __GI_##name) |
| 559 | # define hidden_data_weak(name) _hidden_weak_alias (name, __GI_##name) |
| 560 | # define hidden_data_ver(local, name) strong_data_alias (local, __GI_##name) |
| 561 | # ifdef HAVE_ASM_GLOBAL_DOT_NAME |
| 562 | # define HIDDEN_JUMPTARGET(name) .__GI_##name |
| 563 | # else |
| 564 | # define HIDDEN_JUMPTARGET(name) __GI_##name |
| 565 | # endif |
| 566 | # endif /* __ASSEMBLER__ */ |
| 567 | |
| 568 | #else /* not SHARED */ |
| 569 | |
| 570 | # ifndef __ASSEMBLER__ |
| 571 | # define hidden_proto(name, attrs...) |
| 572 | # else |
| 573 | # define HIDDEN_JUMPTARGET(name) name |
| 574 | # endif /* not __ASSEMBLER__ */ |
| 575 | # define hidden_weak(name) |
| 576 | # define hidden_def(name) |
| 577 | # define hidden_ver(local, name) |
| 578 | # define hidden_data_weak(name) |
| 579 | # define hidden_data_def(name) |
| 580 | # define hidden_data_ver(local, name) |
| 581 | |
| 582 | #endif /* SHARED / not SHARED */ |
| 583 | |
| 584 | |
| 585 | /* uClibc does not support versioning yet. */ |
| 586 | #define versioned_symbol(lib, local, symbol, version) /* weak_alias(local, symbol) */ |
| 587 | #undef hidden_ver |
| 588 | #define hidden_ver(local, name) /* strong_alias(local, __GI_##name) */ |
| 589 | #undef hidden_data_ver |
| 590 | #define hidden_data_ver(local, name) /* strong_alias(local,__GI_##name) */ |
| 591 | |
| 592 | #if !defined NOT_IN_libc |
| 593 | # define libc_hidden_proto(name, attrs...) hidden_proto (name, ##attrs) |
| 594 | # define libc_hidden_def(name) hidden_def (name) |
| 595 | # define libc_hidden_weak(name) hidden_weak (name) |
| 596 | # define libc_hidden_ver(local, name) hidden_ver (local, name) |
| 597 | # define libc_hidden_data_def(name) hidden_data_def (name) |
| 598 | # define libc_hidden_data_weak(name) hidden_data_weak (name) |
| 599 | # define libc_hidden_data_ver(local, name) hidden_data_ver (local, name) |
| 600 | #else |
| 601 | # define libc_hidden_proto(name, attrs...) |
| 602 | # define libc_hidden_def(name) |
| 603 | # define libc_hidden_weak(name) |
| 604 | # define libc_hidden_ver(local, name) |
| 605 | # define libc_hidden_data_def(name) |
| 606 | # define libc_hidden_data_weak(name) |
| 607 | # define libc_hidden_data_ver(local, name) |
| 608 | #endif |
| 609 | |
| 610 | #if defined NOT_IN_libc && defined IS_IN_rtld |
| 611 | # define rtld_hidden_proto(name, attrs...) hidden_proto (name, ##attrs) |
| 612 | # define rtld_hidden_def(name) hidden_def (name) |
| 613 | # define rtld_hidden_weak(name) hidden_weak (name) |
| 614 | # define rtld_hidden_ver(local, name) hidden_ver (local, name) |
| 615 | # define rtld_hidden_data_def(name) hidden_data_def (name) |
| 616 | # define rtld_hidden_data_weak(name) hidden_data_weak (name) |
| 617 | # define rtld_hidden_data_ver(local, name) hidden_data_ver (local, name) |
| 618 | #else |
| 619 | # define rtld_hidden_proto(name, attrs...) |
| 620 | # define rtld_hidden_def(name) |
| 621 | # define rtld_hidden_weak(name) |
| 622 | # define rtld_hidden_ver(local, name) |
| 623 | # define rtld_hidden_data_def(name) |
| 624 | # define rtld_hidden_data_weak(name) |
| 625 | # define rtld_hidden_data_ver(local, name) |
| 626 | #endif |
| 627 | |
| 628 | #if defined NOT_IN_libc && defined IS_IN_libm |
| 629 | # define libm_hidden_proto(name, attrs...) hidden_proto (name, ##attrs) |
| 630 | # define libm_hidden_def(name) hidden_def (name) |
| 631 | # define libm_hidden_weak(name) hidden_weak (name) |
| 632 | # define libm_hidden_ver(local, name) hidden_ver (local, name) |
| 633 | # define libm_hidden_data_def(name) hidden_data_def (name) |
| 634 | # define libm_hidden_data_weak(name) hidden_data_weak (name) |
| 635 | # define libm_hidden_data_ver(local, name) hidden_data_ver (local, name) |
| 636 | #else |
| 637 | # define libm_hidden_proto(name, attrs...) |
| 638 | # define libm_hidden_def(name) |
| 639 | # define libm_hidden_weak(name) |
| 640 | # define libm_hidden_ver(local, name) |
| 641 | # define libm_hidden_data_def(name) |
| 642 | # define libm_hidden_data_weak(name) |
| 643 | # define libm_hidden_data_ver(local, name) |
| 644 | #endif |
| 645 | |
| 646 | #if defined NOT_IN_libc && defined IS_IN_libresolv |
| 647 | # define libresolv_hidden_proto(name, attrs...) hidden_proto (name, ##attrs) |
| 648 | # define libresolv_hidden_def(name) hidden_def (name) |
| 649 | # define libresolv_hidden_weak(name) hidden_weak (name) |
| 650 | # define libresolv_hidden_ver(local, name) hidden_ver (local, name) |
| 651 | # define libresolv_hidden_data_def(name) hidden_data_def (name) |
| 652 | # define libresolv_hidden_data_weak(name) hidden_data_weak (name) |
| 653 | # define libresolv_hidden_data_ver(local, name) hidden_data_ver (local, name) |
| 654 | #else |
| 655 | # define libresolv_hidden_proto(name, attrs...) |
| 656 | # define libresolv_hidden_def(name) |
| 657 | # define libresolv_hidden_weak(name) |
| 658 | # define libresolv_hidden_ver(local, name) |
| 659 | # define libresolv_hidden_data_def(name) |
| 660 | # define libresolv_hidden_data_weak(name) |
| 661 | # define libresolv_hidden_data_ver(local, name) |
| 662 | #endif |
| 663 | |
| 664 | #if defined NOT_IN_libc && defined IS_IN_librt |
| 665 | # define librt_hidden_proto(name, attrs...) hidden_proto (name, ##attrs) |
| 666 | # define librt_hidden_def(name) hidden_def (name) |
| 667 | # define librt_hidden_weak(name) hidden_weak (name) |
| 668 | # define librt_hidden_ver(local, name) hidden_ver (local, name) |
| 669 | # define librt_hidden_data_def(name) hidden_data_def (name) |
| 670 | # define librt_hidden_data_weak(name) hidden_data_weak (name) |
| 671 | # define librt_hidden_data_ver(local, name) hidden_data_ver (local, name) |
| 672 | #else |
| 673 | # define librt_hidden_proto(name, attrs...) |
| 674 | # define librt_hidden_def(name) |
| 675 | # define librt_hidden_weak(name) |
| 676 | # define librt_hidden_ver(local, name) |
| 677 | # define librt_hidden_data_def(name) |
| 678 | # define librt_hidden_data_weak(name) |
| 679 | # define librt_hidden_data_ver(local, name) |
| 680 | #endif |
| 681 | |
| 682 | #if defined NOT_IN_libc && defined IS_IN_libdl |
| 683 | # define libdl_hidden_proto(name, attrs...) hidden_proto (name, ##attrs) |
| 684 | # define libdl_hidden_def(name) hidden_def (name) |
| 685 | # define libdl_hidden_weak(name) hidden_weak (name) |
| 686 | # define libdl_hidden_ver(local, name) hidden_ver (local, name) |
| 687 | # define libdl_hidden_data_def(name) hidden_data_def (name) |
| 688 | # define libdl_hidden_data_weak(name) hidden_data_weak (name) |
| 689 | # define libdl_hidden_data_ver(local, name) hidden_data_ver (local, name) |
| 690 | #else |
| 691 | # define libdl_hidden_proto(name, attrs...) |
| 692 | # define libdl_hidden_def(name) |
| 693 | # define libdl_hidden_weak(name) |
| 694 | # define libdl_hidden_ver(local, name) |
| 695 | # define libdl_hidden_data_def(name) |
| 696 | # define libdl_hidden_data_weak(name) |
| 697 | # define libdl_hidden_data_ver(local, name) |
| 698 | #endif |
| 699 | |
| 700 | #if defined NOT_IN_libc && defined IS_IN_libintl |
| 701 | # define libintl_hidden_proto(name, attrs...) hidden_proto (name, ##attrs) |
| 702 | # define libintl_hidden_def(name) hidden_def (name) |
| 703 | # define libintl_hidden_weak(name) hidden_weak (name) |
| 704 | # define libintl_hidden_ver(local, name) hidden_ver (local, name) |
| 705 | # define libintl_hidden_data_def(name) hidden_data_def (name) |
| 706 | # define libintl_hidden_data_weak(name) hidden_data_weak (name) |
| 707 | # define libintl_hidden_data_ver(local, name) hidden_data_ver(local, name) |
| 708 | #else |
| 709 | # define libintl_hidden_proto(name, attrs...) |
| 710 | # define libintl_hidden_def(name) |
| 711 | # define libintl_hidden_weak(name) |
| 712 | # define libintl_hidden_ver(local, name) |
| 713 | # define libintl_hidden_data_def(name) |
| 714 | # define libintl_hidden_data_weak(name) |
| 715 | # define libintl_hidden_data_ver(local, name) |
| 716 | #endif |
| 717 | |
| 718 | #if defined NOT_IN_libc && defined IS_IN_libnsl |
| 719 | # define libnsl_hidden_proto(name, attrs...) hidden_proto (name, ##attrs) |
| 720 | # define libnsl_hidden_def(name) hidden_def (name) |
| 721 | # define libnsl_hidden_weak(name) hidden_weak (name) |
| 722 | # define libnsl_hidden_ver(local, name) hidden_ver (local, name) |
| 723 | # define libnsl_hidden_data_def(name) hidden_data_def (name) |
| 724 | # define libnsl_hidden_data_weak(name) hidden_data_weak (name) |
| 725 | # define libnsl_hidden_data_ver(local, name) hidden_data_ver (local, name) |
| 726 | #else |
| 727 | # define libnsl_hidden_proto(name, attrs...) |
| 728 | # define libnsl_hidden_def(name) |
| 729 | # define libnsl_hidden_weak(name) |
| 730 | # define libnsl_hidden_ver(local, name) |
| 731 | # define libnsl_hidden_data_def(name) |
| 732 | # define libnsl_hidden_data_weak(name) |
| 733 | # define libnsl_hidden_data_ver(local, name) |
| 734 | #endif |
| 735 | |
| 736 | #if defined NOT_IN_libc && defined IS_IN_libutil |
| 737 | # define libutil_hidden_proto(name, attrs...) hidden_proto (name, ##attrs) |
| 738 | # define libutil_hidden_def(name) hidden_def (name) |
| 739 | # define libutil_hidden_weak(name) hidden_weak (name) |
| 740 | # define libutil_hidden_ver(local, name) hidden_ver (local, name) |
| 741 | # define libutil_hidden_data_def(name) hidden_data_def (name) |
| 742 | # define libutil_hidden_data_weak(name) hidden_data_weak (name) |
| 743 | # define libutil_hidden_data_ver(local, name) hidden_data_ver (local, name) |
| 744 | #else |
| 745 | # define libutil_hidden_proto(name, attrs...) |
| 746 | # define libutil_hidden_def(name) |
| 747 | # define libutil_hidden_weak(name) |
| 748 | # define libutil_hidden_ver(local, name) |
| 749 | # define libutil_hidden_data_def(name) |
| 750 | # define libutil_hidden_data_weak(name) |
| 751 | # define libutil_hidden_data_ver(local, name) |
| 752 | #endif |
| 753 | |
| 754 | #if defined NOT_IN_libc && defined IS_IN_libcrypt |
| 755 | # define libcrypt_hidden_proto(name, attrs...) hidden_proto (name, ##attrs) |
| 756 | # define libcrypt_hidden_def(name) hidden_def (name) |
| 757 | # define libcrypt_hidden_weak(name) hidden_weak (name) |
| 758 | # define libcrypt_hidden_ver(local, name) hidden_ver (local, name) |
| 759 | # define libcrypt_hidden_data_def(name) hidden_data_def (name) |
| 760 | # define libcrypt_hidden_data_weak(name) hidden_data_weak (name) |
| 761 | # define libcrypt_hidden_data_ver(local, name) hidden_data_ver (local, name) |
| 762 | #else |
| 763 | # define libcrypt_hidden_proto(name, attrs...) |
| 764 | # define libcrypt_hidden_def(name) |
| 765 | # define libcrypt_hidden_weak(name) |
| 766 | # define libcrypt_hidden_ver(local, name) |
| 767 | # define libcrypt_hidden_data_def(name) |
| 768 | # define libcrypt_hidden_data_weak(name) |
| 769 | # define libcrypt_hidden_data_ver(local, name) |
| 770 | #endif |
| 771 | |
| 772 | #if defined NOT_IN_libc && defined IS_IN_libpthread |
| 773 | # define libpthread_hidden_proto(name, attrs...) hidden_proto (name, ##attrs) |
| 774 | # define libpthread_hidden_def(name) hidden_def (name) |
| 775 | # define libpthread_hidden_weak(name) hidden_weak (name) |
| 776 | # define libpthread_hidden_ver(local, name) hidden_ver (local, name) |
| 777 | # define libpthread_hidden_data_def(name) hidden_data_def (name) |
| 778 | # define libpthread_hidden_data_weak(name) hidden_data_weak (name) |
| 779 | # define libpthread_hidden_data_ver(local, name) hidden_data_ver (local, name) |
| 780 | #else |
| 781 | # define libpthread_hidden_proto(name, attrs...) |
| 782 | # define libpthread_hidden_def(name) |
| 783 | # define libpthread_hidden_weak(name) |
| 784 | # define libpthread_hidden_ver(local, name) |
| 785 | # define libpthread_hidden_data_def(name) |
| 786 | # define libpthread_hidden_data_weak(name) |
| 787 | # define libpthread_hidden_data_ver(local, name) |
| 788 | #endif |
| 789 | |
| 790 | #endif /* libc-symbols.h */ |