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28f540f4 RM |
1 | /* Support macros for making weak and strong aliases for symbols, |
2 | and for using symbol sets and linker warnings with GNU ld. | |
f7a9f785 | 3 | Copyright (C) 1995-2016 Free Software Foundation, Inc. |
5290baf0 | 4 | This file is part of the GNU C Library. |
28f540f4 | 5 | |
5290baf0 | 6 | The GNU C Library is free software; you can redistribute it and/or |
41bdb6e2 AJ |
7 | modify it under the terms of the GNU Lesser General Public |
8 | License as published by the Free Software Foundation; either | |
9 | version 2.1 of the License, or (at your option) any later version. | |
28f540f4 | 10 | |
5290baf0 UD |
11 | The GNU C Library is distributed in the hope that it will be useful, |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
41bdb6e2 | 14 | Lesser General Public License for more details. |
28f540f4 | 15 | |
41bdb6e2 | 16 | You should have received a copy of the GNU Lesser General Public |
59ba27a6 PE |
17 | License along with the GNU C Library; if not, see |
18 | <http://www.gnu.org/licenses/>. */ | |
28f540f4 RM |
19 | |
20 | #ifndef _LIBC_SYMBOLS_H | |
5290baf0 | 21 | #define _LIBC_SYMBOLS_H 1 |
28f540f4 | 22 | |
279bc5b3 | 23 | #define IN_MODULE PASTE_NAME (MODULE_, MODULE_NAME) |
9cd47470 SP |
24 | #define IS_IN(lib) (IN_MODULE == MODULE_##lib) |
25 | ||
a10178bd SP |
26 | /* Returns true if the current module is a versioned library. Versioned |
27 | library names culled from shlib-versions files are assigned a MODULE_* | |
28 | value lower than MODULE_LIBS_BEGIN. */ | |
29 | #define IS_IN_LIB (IN_MODULE > MODULE_LIBS_BEGIN) | |
30 | ||
279bc5b3 SP |
31 | #define PASTE_NAME(a,b) PASTE_NAME1 (a,b) |
32 | #define PASTE_NAME1(a,b) a##b | |
33 | ||
28f540f4 RM |
34 | /* This file's macros are included implicitly in the compilation of every |
35 | file in the C library by -imacros. | |
36 | ||
37 | We include config.h which is generated by configure. | |
210dd782 | 38 | It should define for us the following symbol: |
28f540f4 | 39 | |
c224a18a | 40 | * HAVE_ASM_SET_DIRECTIVE if we have `.set B, A' instead of `A = B'. |
28f540f4 RM |
41 | |
42 | */ | |
28f540f4 | 43 | |
92777700 RM |
44 | /* This is defined for the compilation of all C library code. features.h |
45 | tests this to avoid inclusion of stubs.h while compiling the library, | |
46 | before stubs.h has been generated. Some library code that is shared | |
47 | with other packages also tests this symbol to see if it is being | |
48 | compiled as part of the C library. We must define this before including | |
49 | config.h, because it makes some definitions conditional on whether libc | |
50 | itself is being compiled, or just some generator program. */ | |
c709e372 | 51 | #define _LIBC 1 |
92777700 | 52 | |
d3669add RM |
53 | /* Enable declarations of GNU extensions, since we are compiling them. */ |
54 | #define _GNU_SOURCE 1 | |
55 | ||
92777700 | 56 | #include <config.h> |
28f540f4 | 57 | |
26ffd5e6 RM |
58 | /* Define this for the benefit of portable GNU code that wants to check it. |
59 | Code that checks with #if will not #include <config.h> again, since we've | |
60 | already done it (and this file is implicitly included in every compile, | |
61 | via -include). Code that checks with #ifdef will #include <config.h>, | |
62 | but that file should always be idempotent (i.e., it's just #define/#undef | |
63 | and nothing else anywhere should be changing the macro state it touches), | |
64 | so it's harmless. */ | |
65 | #define HAVE_CONFIG_H 0 | |
66 | ||
3f3dd810 SP |
67 | /* Define these macros for the benefit of portable GNU code that wants to check |
68 | them. Of course, STDC_HEADERS is never false when building libc! */ | |
26ffd5e6 | 69 | #define STDC_HEADERS 1 |
3f3dd810 SP |
70 | #define HAVE_MBSTATE_T 1 |
71 | #define HAVE_MBSRTOWCS 1 | |
a476ac4b SP |
72 | #define HAVE_LIBINTL_H 1 |
73 | #define HAVE_WCTYPE_H 1 | |
74 | #define HAVE_ISWCTYPE 1 | |
75 | #define ENABLE_NLS 1 | |
26ffd5e6 | 76 | |
0269750c | 77 | /* The symbols in all the user (non-_) macros are C symbols. */ |
28f540f4 | 78 | |
28f540f4 | 79 | #ifndef __SYMBOL_PREFIX |
a0da5fe1 | 80 | # define __SYMBOL_PREFIX |
28f540f4 RM |
81 | #endif |
82 | ||
83 | #ifndef C_SYMBOL_NAME | |
a0da5fe1 | 84 | # define C_SYMBOL_NAME(name) name |
28f540f4 RM |
85 | #endif |
86 | ||
b15cb495 UD |
87 | #ifndef ASM_LINE_SEP |
88 | # define ASM_LINE_SEP ; | |
89 | #endif | |
90 | ||
428383e8 UD |
91 | #ifndef __ASSEMBLER__ |
92 | /* GCC understands weak symbols and aliases; use its interface where | |
93 | possible, instead of embedded assembly language. */ | |
d02907df | 94 | |
428383e8 | 95 | /* Define ALIASNAME as a strong alias for NAME. */ |
c62f5cab GM |
96 | # define strong_alias(name, aliasname) _strong_alias(name, aliasname) |
97 | # define _strong_alias(name, aliasname) \ | |
428383e8 UD |
98 | extern __typeof (name) aliasname __attribute__ ((alias (#name))); |
99 | ||
100 | /* This comes between the return type and function name in | |
101 | a function definition to make that definition weak. */ | |
102 | # define weak_function __attribute__ ((weak)) | |
103 | # define weak_const_function __attribute__ ((weak, __const__)) | |
104 | ||
428383e8 UD |
105 | /* Define ALIASNAME as a weak alias for NAME. |
106 | If weak aliases are not available, this defines a strong alias. */ | |
a0da5fe1 UD |
107 | # define weak_alias(name, aliasname) _weak_alias (name, aliasname) |
108 | # define _weak_alias(name, aliasname) \ | |
428383e8 UD |
109 | extern __typeof (name) aliasname __attribute__ ((weak, alias (#name))); |
110 | ||
11bf311e | 111 | /* Same as WEAK_ALIAS, but mark symbol as hidden. */ |
a0da5fe1 | 112 | # define weak_hidden_alias(name, aliasname) \ |
11bf311e | 113 | _weak_hidden_alias (name, aliasname) |
a0da5fe1 | 114 | # define _weak_hidden_alias(name, aliasname) \ |
11bf311e UD |
115 | extern __typeof (name) aliasname \ |
116 | __attribute__ ((weak, alias (#name), __visibility__ ("hidden"))); | |
117 | ||
428383e8 | 118 | /* Declare SYMBOL as weak undefined symbol (resolved to 0 if not defined). */ |
a0da5fe1 UD |
119 | # define weak_extern(symbol) _weak_extern (weak symbol) |
120 | # define _weak_extern(expr) _Pragma (#expr) | |
428383e8 | 121 | |
ef4f9764 FW |
122 | /* In shared builds, the expression call_function_static_weak |
123 | (FUNCTION-SYMBOL, ARGUMENTS) invokes FUNCTION-SYMBOL (an | |
124 | identifier) unconditionally, with the (potentially empty) argument | |
125 | list ARGUMENTS. In static builds, if FUNCTION-SYMBOL has a | |
126 | definition, the function is invoked as before; if FUNCTION-SYMBOL | |
127 | is NULL, no call is performed. */ | |
128 | # ifdef SHARED | |
129 | # define call_function_static_weak(func, ...) func (__VA_ARGS__) | |
130 | # else /* !SHARED */ | |
131 | # define call_function_static_weak(func, ...) \ | |
132 | ({ \ | |
133 | extern __typeof__ (func) func weak_function; \ | |
134 | (func != NULL ? func (__VA_ARGS__) : (void)0); \ | |
135 | }) | |
136 | # endif | |
428383e8 UD |
137 | |
138 | #else /* __ASSEMBLER__ */ | |
139 | ||
140 | # ifdef HAVE_ASM_SET_DIRECTIVE | |
5ca10a0c | 141 | # define strong_alias(original, alias) \ |
7b8e0d49 | 142 | .globl C_SYMBOL_NAME (alias) ASM_LINE_SEP \ |
c843e065 | 143 | .set C_SYMBOL_NAME (alias),C_SYMBOL_NAME (original) |
5ca10a0c | 144 | # define strong_data_alias(original, alias) strong_alias(original, alias) |
dfd2257a | 145 | # else |
5ca10a0c | 146 | # define strong_alias(original, alias) \ |
7b8e0d49 | 147 | .globl C_SYMBOL_NAME (alias) ASM_LINE_SEP \ |
c843e065 | 148 | C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original) |
5ca10a0c | 149 | # define strong_data_alias(original, alias) strong_alias(original, alias) |
dfd2257a | 150 | # endif |
d02907df | 151 | |
210dd782 | 152 | # define weak_alias(original, alias) \ |
c843e065 | 153 | .weak C_SYMBOL_NAME (alias) ASM_LINE_SEP \ |
28f540f4 | 154 | C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original) |
e6964dd4 | 155 | |
210dd782 | 156 | # define weak_extern(symbol) \ |
af5b3bc3 | 157 | .weak C_SYMBOL_NAME (symbol) |
d02907df | 158 | |
428383e8 | 159 | #endif /* __ASSEMBLER__ */ |
958f803f | 160 | |
dfd2257a UD |
161 | /* On some platforms we can make internal function calls (i.e., calls of |
162 | functions not exported) a bit faster by using a different calling | |
163 | convention. */ | |
164 | #ifndef internal_function | |
165 | # define internal_function /* empty */ | |
166 | #endif | |
28f540f4 | 167 | |
e862aada UD |
168 | /* Determine the return address. */ |
169 | #define RETURN_ADDRESS(nr) \ | |
170 | __builtin_extract_return_addr (__builtin_return_address (nr)) | |
171 | ||
44c8d1a2 RM |
172 | /* When a reference to SYMBOL is encountered, the linker will emit a |
173 | warning message MSG. */ | |
fd26970f | 174 | /* We want the .gnu.warning.SYMBOL section to be unallocated. */ |
75b0964b | 175 | #define __make_section_unallocated(section_string) \ |
b15cb495 | 176 | asm (".section " section_string "\n\t.previous"); |
fd26970f | 177 | |
b15cb495 UD |
178 | /* Tacking on "\n\t#" to the section name makes gcc put it's bogus |
179 | section attributes on what looks like a comment to the assembler. */ | |
0269750c UD |
180 | #ifdef HAVE_SECTION_QUOTES |
181 | # define __sec_comment "\"\n\t#\"" | |
182 | #else | |
183 | # define __sec_comment "\n\t#" | |
184 | #endif | |
185 | #define link_warning(symbol, msg) \ | |
e26dd47f | 186 | __make_section_unallocated (".gnu.warning." #symbol) \ |
44c8d1a2 | 187 | static const char __evoke_link_warning_##symbol[] \ |
6c5775c3 | 188 | __attribute__ ((used, section (".gnu.warning." #symbol __sec_comment))) \ |
c877418f | 189 | = msg; |
0269750c | 190 | #define libc_freeres_ptr(decl) \ |
362f5ae2 | 191 | __make_section_unallocated ("__libc_freeres_ptrs, \"aw\", %nobits") \ |
c877418f | 192 | decl __attribute__ ((section ("__libc_freeres_ptrs" __sec_comment))) |
0269750c | 193 | #define __libc_freeres_fn_section \ |
c877418f | 194 | __attribute__ ((section ("__libc_freeres_fn"))) |
0269750c | 195 | |
c877418f RM |
196 | #define libc_freeres_fn(name) \ |
197 | static void name (void) __attribute_used__ __libc_freeres_fn_section; \ | |
198 | text_set_element (__libc_subfreeres, name); \ | |
199 | static void name (void) | |
28f540f4 RM |
200 | |
201 | /* A canned warning for sysdeps/stub functions. */ | |
202 | #define stub_warning(name) \ | |
561bcb80 | 203 | __make_section_unallocated (".gnu.glibc-stub." #name) \ |
cd525923 | 204 | link_warning (name, #name " is not implemented and will always fail") |
5f9e57ba | 205 | |
2f7f7bc6 UD |
206 | /* Warning for linking functions calling dlopen into static binaries. */ |
207 | #ifdef SHARED | |
208 | #define static_link_warning(name) | |
209 | #else | |
210 | #define static_link_warning(name) static_link_warning1(name) | |
211 | #define static_link_warning1(name) \ | |
212 | link_warning(name, "Using '" #name "' in statically linked applications \ | |
213 | requires at runtime the shared libraries from the glibc version used \ | |
214 | for linking") | |
215 | #endif | |
b88ac073 | 216 | |
11bf311e UD |
217 | /* Declare SYMBOL to be TYPE (`function' or `object') of SIZE bytes |
218 | alias to ORIGINAL, when the assembler supports such declarations | |
219 | (such as in ELF). | |
b88ac073 RM |
220 | This is only necessary when defining something in assembly, or playing |
221 | funny alias games where the size should be other than what the compiler | |
222 | thinks it is. */ | |
11bf311e UD |
223 | #define declare_symbol_alias(symbol, original, type, size) \ |
224 | declare_symbol_alias_1 (symbol, original, type, size) | |
b67e9372 MP |
225 | #ifdef __ASSEMBLER__ |
226 | # define declare_symbol_alias_1(symbol, original, type, size) \ | |
227 | strong_alias (original, symbol); \ | |
228 | .type C_SYMBOL_NAME (symbol), %##type; \ | |
229 | .size C_SYMBOL_NAME (symbol), size | |
230 | #else /* Not __ASSEMBLER__. */ | |
231 | # define declare_symbol_alias_1(symbol, original, type, size) \ | |
232 | asm (".globl " __SYMBOL_PREFIX #symbol \ | |
233 | "\n\t" declare_symbol_alias_1_alias (symbol, original) \ | |
234 | "\n\t.type " __SYMBOL_PREFIX #symbol ", " \ | |
235 | "%" #type \ | |
236 | "\n\t.size " __SYMBOL_PREFIX #symbol ", " #size); | |
237 | # ifdef HAVE_ASM_SET_DIRECTIVE | |
238 | # define declare_symbol_alias_1_alias(symbol, original) \ | |
239 | ".set " __SYMBOL_PREFIX #symbol ", " __SYMBOL_PREFIX #original | |
240 | # else | |
241 | # define declare_symbol_alias_1_alias(symbol, original) \ | |
242 | __SYMBOL_PREFIX #symbol " = " __SYMBOL_PREFIX #original | |
243 | # endif /* HAVE_ASM_SET_DIRECTIVE */ | |
244 | #endif /* __ASSEMBLER__ */ | |
b88ac073 RM |
245 | |
246 | ||
5f9e57ba | 247 | /* |
28f540f4 | 248 | \f |
5f9e57ba RM |
249 | */ |
250 | ||
28f540f4 RM |
251 | /* Symbol set support macros. */ |
252 | ||
28f540f4 | 253 | /* Make SYMBOL, which is in the text segment, an element of SET. */ |
0269750c | 254 | #define text_set_element(set, symbol) _elf_set_element(set, symbol) |
28f540f4 | 255 | /* Make SYMBOL, which is in the data segment, an element of SET. */ |
0269750c | 256 | #define data_set_element(set, symbol) _elf_set_element(set, symbol) |
28f540f4 | 257 | /* Make SYMBOL, which is in the bss segment, an element of SET. */ |
0269750c | 258 | #define bss_set_element(set, symbol) _elf_set_element(set, symbol) |
28f540f4 RM |
259 | |
260 | /* These are all done the same way in ELF. | |
261 | There is a new section created for each set. */ | |
0269750c | 262 | #ifdef SHARED |
53afa8d9 RM |
263 | /* When building a shared library, make the set section writable, |
264 | because it will need to be relocated at run time anyway. */ | |
0269750c | 265 | # define _elf_set_element(set, symbol) \ |
53afa8d9 | 266 | static const void *__elf_set_##set##_element_##symbol##__ \ |
6c5775c3 | 267 | __attribute__ ((used, section (#set))) = &(symbol) |
0269750c UD |
268 | #else |
269 | # define _elf_set_element(set, symbol) \ | |
28f540f4 | 270 | static const void *const __elf_set_##set##_element_##symbol##__ \ |
6c5775c3 | 271 | __attribute__ ((used, section (#set))) = &(symbol) |
0269750c | 272 | #endif |
28f540f4 RM |
273 | |
274 | /* Define SET as a symbol set. This may be required (it is in a.out) to | |
275 | be able to use the set's contents. */ | |
0269750c | 276 | #define symbol_set_define(set) symbol_set_declare(set) |
28f540f4 | 277 | |
20792f99 RM |
278 | /* Declare SET for use in this module, if defined in another module. |
279 | In a shared library, this is always local to that shared object. | |
280 | For static linking, the set might be wholly absent and so we use | |
281 | weak references. */ | |
0269750c | 282 | #define symbol_set_declare(set) \ |
6f1e513d RH |
283 | extern char const __start_##set[] __symbol_set_attribute; \ |
284 | extern char const __stop_##set[] __symbol_set_attribute; | |
0269750c UD |
285 | #ifdef SHARED |
286 | # define __symbol_set_attribute attribute_hidden | |
287 | #else | |
288 | # define __symbol_set_attribute __attribute__ ((weak)) | |
289 | #endif | |
28f540f4 RM |
290 | |
291 | /* Return a pointer (void *const *) to the first element of SET. */ | |
0269750c | 292 | #define symbol_set_first_element(set) ((void *const *) (&__start_##set)) |
28f540f4 RM |
293 | |
294 | /* Return true iff PTR (a void *const *) has been incremented | |
295 | past the last element in SET. */ | |
0269750c | 296 | #define symbol_set_end_p(set, ptr) ((ptr) >= (void *const *) &__stop_##set) |
28f540f4 | 297 | |
968dc26d FW |
298 | /* Use symbol_version_reference to specify the version a symbol |
299 | reference should link to. Use symbol_version or | |
300 | default_symbol_version for the definition of a versioned symbol. | |
301 | The difference is that the latter is a no-op in non-shared | |
302 | builds. */ | |
303 | #ifdef __ASSEMBLER__ | |
304 | # define symbol_version_reference(real, name, version) \ | |
305 | .symver real, name##@##version | |
306 | #else /* !__ASSEMBLER__ */ | |
307 | # define symbol_version_reference(real, name, version) \ | |
308 | __asm__ (".symver " #real "," #name "@" #version) | |
309 | #endif | |
310 | ||
3f2e46a4 | 311 | #ifdef SHARED |
ebdf53a7 | 312 | # define symbol_version(real, name, version) \ |
968dc26d | 313 | symbol_version_reference(real, name, version) |
ebdf53a7 GM |
314 | # define default_symbol_version(real, name, version) \ |
315 | _default_symbol_version(real, name, version) | |
316 | # ifdef __ASSEMBLER__ | |
5ca10a0c | 317 | # define _default_symbol_version(real, name, version) \ |
da2d1bc5 UD |
318 | .symver real, name##@##@##version |
319 | # else | |
5ca10a0c | 320 | # define _default_symbol_version(real, name, version) \ |
f2ea0f5b | 321 | __asm__ (".symver " #real "," #name "@@" #version) |
da2d1bc5 | 322 | # endif |
1ea89a40 UD |
323 | #else |
324 | # define symbol_version(real, name, version) | |
da2d1bc5 UD |
325 | # define default_symbol_version(real, name, version) \ |
326 | strong_alias(real, name) | |
1ea89a40 UD |
327 | #endif |
328 | ||
11bf311e | 329 | #if defined SHARED || defined LIBC_NONSHARED |
e6caf4e1 UD |
330 | # define attribute_hidden __attribute__ ((visibility ("hidden"))) |
331 | #else | |
332 | # define attribute_hidden | |
333 | #endif | |
334 | ||
3ce1f295 | 335 | #define attribute_tls_model_ie __attribute__ ((tls_model ("initial-exec"))) |
9b21e6bc | 336 | |
11bf311e | 337 | #define attribute_relro __attribute__ ((section (".data.rel.ro"))) |
392a6b52 | 338 | |
de659123 NA |
339 | |
340 | /* Used to disable stack protection in sensitive places, like ifunc | |
341 | resolvers and early static TLS init. */ | |
342 | #ifdef HAVE_CC_NO_STACK_PROTECTOR | |
343 | # define inhibit_stack_protector \ | |
344 | __attribute__ ((__optimize__ ("-fno-stack-protector"))) | |
345 | #else | |
346 | # define inhibit_stack_protector | |
347 | #endif | |
348 | ||
37ba7d66 UD |
349 | /* The following macros are used for PLT bypassing within libc.so |
350 | (and if needed other libraries similarly). | |
351 | First of all, you need to have the function prototyped somewhere, | |
352 | say in foo/foo.h: | |
353 | ||
354 | int foo (int __bar); | |
355 | ||
356 | If calls to foo within libc.so should always go to foo defined in libc.so, | |
357 | then in include/foo.h you add: | |
358 | ||
359 | libc_hidden_proto (foo) | |
360 | ||
361 | line and after the foo function definition: | |
362 | ||
363 | int foo (int __bar) | |
364 | { | |
365 | return __bar; | |
366 | } | |
367 | libc_hidden_def (foo) | |
368 | ||
369 | or | |
370 | ||
371 | int foo (int __bar) | |
372 | { | |
373 | return __bar; | |
374 | } | |
375 | libc_hidden_weak (foo) | |
376 | ||
5536dfcb | 377 | Similarly for global data. If references to foo within libc.so should |
c843e065 RM |
378 | always go to foo defined in libc.so, then in include/foo.h you add: |
379 | ||
380 | libc_hidden_proto (foo) | |
381 | ||
382 | line and after foo's definition: | |
383 | ||
384 | int foo = INITIAL_FOO_VALUE; | |
385 | libc_hidden_data_def (foo) | |
386 | ||
387 | or | |
388 | ||
389 | int foo = INITIAL_FOO_VALUE; | |
390 | libc_hidden_data_weak (foo) | |
391 | ||
5536dfcb | 392 | If foo is normally just an alias (strong or weak) to some other function, |
37ba7d66 UD |
393 | you should use the normal strong_alias first, then add libc_hidden_def |
394 | or libc_hidden_weak: | |
395 | ||
396 | int baz (int __bar) | |
397 | { | |
398 | return __bar; | |
399 | } | |
400 | strong_alias (baz, foo) | |
401 | libc_hidden_weak (foo) | |
402 | ||
403 | If the function should be internal to multiple objects, say ld.so and | |
404 | libc.so, the best way is to use: | |
405 | ||
9cd47470 | 406 | #if IS_IN (libc) || IS_IN (rtld) |
37ba7d66 UD |
407 | hidden_proto (foo) |
408 | #endif | |
409 | ||
410 | in include/foo.h and the normal macros at all function definitions | |
411 | depending on what DSO they belong to. | |
412 | ||
413 | If versioned_symbol macro is used to define foo, | |
414 | libc_hidden_ver macro should be used, as in: | |
415 | ||
416 | int __real_foo (int __bar) | |
417 | { | |
418 | return __bar; | |
419 | } | |
420 | versioned_symbol (libc, __real_foo, foo, GLIBC_2_1); | |
421 | libc_hidden_ver (__real_foo, foo) */ | |
422 | ||
3f2e46a4 | 423 | #if defined SHARED && !defined NO_HIDDEN |
37ba7d66 | 424 | # ifndef __ASSEMBLER__ |
11bf311e | 425 | # define __hidden_proto_hiddenattr(attrs...) \ |
81cb0d82 | 426 | __attribute__ ((visibility ("hidden"), ##attrs)) |
81cb0d82 | 427 | # define hidden_proto(name, attrs...) \ |
699df45b JM |
428 | __hidden_proto (name, , __GI_##name, ##attrs) |
429 | # define hidden_tls_proto(name, attrs...) \ | |
430 | __hidden_proto (name, __thread, __GI_##name, ##attrs) | |
431 | # define __hidden_proto(name, thread, internal, attrs...) \ | |
432 | extern thread __typeof (name) name __asm__ (__hidden_asmname (#internal)) \ | |
81cb0d82 | 433 | __hidden_proto_hiddenattr (attrs); |
37ba7d66 UD |
434 | # define __hidden_asmname(name) \ |
435 | __hidden_asmname1 (__USER_LABEL_PREFIX__, name) | |
436 | # define __hidden_asmname1(prefix, name) __hidden_asmname2(prefix, name) | |
437 | # define __hidden_asmname2(prefix, name) #prefix name | |
61995d3e RM |
438 | # define __hidden_ver1(local, internal, name) \ |
439 | extern __typeof (name) __EI_##name __asm__(__hidden_asmname (#internal)); \ | |
440 | extern __typeof (name) __EI_##name \ | |
441 | __attribute__((alias (__hidden_asmname (#local)))) | |
442 | # define hidden_ver(local, name) __hidden_ver1(local, __GI_##name, name); | |
443 | # define hidden_data_ver(local, name) hidden_ver(local, name) | |
444 | # define hidden_def(name) __hidden_ver1(__GI_##name, name, name); | |
445 | # define hidden_data_def(name) hidden_def(name) | |
446 | # define hidden_weak(name) \ | |
447 | __hidden_ver1(__GI_##name, name, name) __attribute__((weak)); | |
448 | # define hidden_data_weak(name) hidden_weak(name) | |
7b57bfe5 UD |
449 | # define hidden_nolink(name, lib, version) \ |
450 | __hidden_nolink1 (__GI_##name, __EI_##name, name, VERSION_##lib##_##version) | |
451 | # define __hidden_nolink1(local, internal, name, version) \ | |
452 | __hidden_nolink2 (local, internal, name, version) | |
453 | # define __hidden_nolink2(local, internal, name, version) \ | |
454 | extern __typeof (name) internal __attribute__ ((alias (#local))); \ | |
455 | __hidden_nolink3 (local, internal, #name "@" #version) | |
456 | # define __hidden_nolink3(local, internal, vername) \ | |
457 | __asm__ (".symver " #internal ", " vername); | |
37ba7d66 UD |
458 | # else |
459 | /* For assembly, we need to do the opposite of what we do in C: | |
460 | in assembly gcc __REDIRECT stuff is not in place, so functions | |
461 | are defined by its normal name and we need to create the | |
462 | __GI_* alias to it, in C __REDIRECT causes the function definition | |
463 | to use __GI_* name and we need to add alias to the real name. | |
4547dee3 RM |
464 | There is no reason to use hidden_weak over hidden_def in assembly, |
465 | but we provide it for consistency with the C usage. | |
466 | hidden_proto doesn't make sense for assembly but the equivalent | |
dce8f2b6 | 467 | is to call via the HIDDEN_JUMPTARGET macro instead of JUMPTARGET. */ |
4547dee3 RM |
468 | # define hidden_def(name) strong_alias (name, __GI_##name) |
469 | # define hidden_weak(name) hidden_def (name) | |
37ba7d66 | 470 | # define hidden_ver(local, name) strong_alias (local, __GI_##name) |
c843e065 RM |
471 | # define hidden_data_def(name) strong_data_alias (name, __GI_##name) |
472 | # define hidden_data_weak(name) hidden_data_def (name) | |
473 | # define hidden_data_ver(local, name) strong_data_alias (local, __GI_##name) | |
5ca10a0c | 474 | # define HIDDEN_JUMPTARGET(name) __GI_##name |
37ba7d66 UD |
475 | # endif |
476 | #else | |
4547dee3 | 477 | # ifndef __ASSEMBLER__ |
81cb0d82 | 478 | # define hidden_proto(name, attrs...) |
699df45b | 479 | # define hidden_tls_proto(name, attrs...) |
4547dee3 RM |
480 | # else |
481 | # define HIDDEN_JUMPTARGET(name) JUMPTARGET(name) | |
482 | # endif /* Not __ASSEMBLER__ */ | |
483 | # define hidden_weak(name) | |
37ba7d66 UD |
484 | # define hidden_def(name) |
485 | # define hidden_ver(local, name) | |
c843e065 RM |
486 | # define hidden_data_weak(name) |
487 | # define hidden_data_def(name) | |
488 | # define hidden_data_ver(local, name) | |
1792c087 | 489 | # define hidden_nolink(name, lib, version) |
37ba7d66 UD |
490 | #endif |
491 | ||
4f41c682 | 492 | #if IS_IN (libc) |
81cb0d82 | 493 | # define libc_hidden_proto(name, attrs...) hidden_proto (name, ##attrs) |
699df45b | 494 | # define libc_hidden_tls_proto(name, attrs...) hidden_tls_proto (name, ##attrs) |
37ba7d66 UD |
495 | # define libc_hidden_def(name) hidden_def (name) |
496 | # define libc_hidden_weak(name) hidden_weak (name) | |
021db4be AJ |
497 | # ifdef LINK_OBSOLETE_RPC |
498 | /* libc_hidden_nolink_sunrpc should only get used in sunrpc code. */ | |
499 | # define libc_hidden_nolink_sunrpc(name, version) hidden_def (name) | |
500 | # else | |
501 | # define libc_hidden_nolink_sunrpc(name, version) hidden_nolink (name, libc, version) | |
502 | # endif | |
37ba7d66 | 503 | # define libc_hidden_ver(local, name) hidden_ver (local, name) |
c843e065 RM |
504 | # define libc_hidden_data_def(name) hidden_data_def (name) |
505 | # define libc_hidden_data_weak(name) hidden_data_weak (name) | |
506 | # define libc_hidden_data_ver(local, name) hidden_data_ver (local, name) | |
37ba7d66 | 507 | #else |
81cb0d82 | 508 | # define libc_hidden_proto(name, attrs...) |
699df45b | 509 | # define libc_hidden_tls_proto(name, attrs...) |
37ba7d66 UD |
510 | # define libc_hidden_def(name) |
511 | # define libc_hidden_weak(name) | |
512 | # define libc_hidden_ver(local, name) | |
c843e065 RM |
513 | # define libc_hidden_data_def(name) |
514 | # define libc_hidden_data_weak(name) | |
515 | # define libc_hidden_data_ver(local, name) | |
37ba7d66 UD |
516 | #endif |
517 | ||
9cd47470 | 518 | #if IS_IN (rtld) |
81cb0d82 | 519 | # define rtld_hidden_proto(name, attrs...) hidden_proto (name, ##attrs) |
699df45b | 520 | # define rtld_hidden_tls_proto(name, attrs...) hidden_tls_proto (name, ##attrs) |
37ba7d66 UD |
521 | # define rtld_hidden_def(name) hidden_def (name) |
522 | # define rtld_hidden_weak(name) hidden_weak (name) | |
523 | # define rtld_hidden_ver(local, name) hidden_ver (local, name) | |
c843e065 RM |
524 | # define rtld_hidden_data_def(name) hidden_data_def (name) |
525 | # define rtld_hidden_data_weak(name) hidden_data_weak (name) | |
526 | # define rtld_hidden_data_ver(local, name) hidden_data_ver (local, name) | |
37ba7d66 | 527 | #else |
81cb0d82 | 528 | # define rtld_hidden_proto(name, attrs...) |
699df45b | 529 | # define rtld_hidden_tls_proto(name, attrs...) |
37ba7d66 UD |
530 | # define rtld_hidden_def(name) |
531 | # define rtld_hidden_weak(name) | |
532 | # define rtld_hidden_ver(local, name) | |
c843e065 RM |
533 | # define rtld_hidden_data_def(name) |
534 | # define rtld_hidden_data_weak(name) | |
535 | # define rtld_hidden_data_ver(local, name) | |
37ba7d66 UD |
536 | #endif |
537 | ||
9cd47470 | 538 | #if IS_IN (libm) |
81cb0d82 | 539 | # define libm_hidden_proto(name, attrs...) hidden_proto (name, ##attrs) |
699df45b | 540 | # define libm_hidden_tls_proto(name, attrs...) hidden_tls_proto (name, ##attrs) |
37ba7d66 UD |
541 | # define libm_hidden_def(name) hidden_def (name) |
542 | # define libm_hidden_weak(name) hidden_weak (name) | |
543 | # define libm_hidden_ver(local, name) hidden_ver (local, name) | |
c843e065 RM |
544 | # define libm_hidden_data_def(name) hidden_data_def (name) |
545 | # define libm_hidden_data_weak(name) hidden_data_weak (name) | |
546 | # define libm_hidden_data_ver(local, name) hidden_data_ver (local, name) | |
37ba7d66 | 547 | #else |
81cb0d82 | 548 | # define libm_hidden_proto(name, attrs...) |
699df45b | 549 | # define libm_hidden_tls_proto(name, attrs...) |
37ba7d66 UD |
550 | # define libm_hidden_def(name) |
551 | # define libm_hidden_weak(name) | |
552 | # define libm_hidden_ver(local, name) | |
c843e065 RM |
553 | # define libm_hidden_data_def(name) |
554 | # define libm_hidden_data_weak(name) | |
555 | # define libm_hidden_data_ver(local, name) | |
37ba7d66 UD |
556 | #endif |
557 | ||
829a679f AS |
558 | #if IS_IN (libmvec) |
559 | # define libmvec_hidden_proto(name, attrs...) hidden_proto (name, ##attrs) | |
560 | # define libmvec_hidden_tls_proto(name, attrs...) hidden_tls_proto (name, ##attrs) | |
561 | # define libmvec_hidden_def(name) hidden_def (name) | |
562 | # define libmvec_hidden_weak(name) hidden_weak (name) | |
563 | # define libmvec_hidden_ver(local, name) hidden_ver (local, name) | |
564 | # define libmvec_hidden_data_def(name) hidden_data_def (name) | |
565 | # define libmvec_hidden_data_weak(name) hidden_data_weak (name) | |
566 | # define libmvec_hidden_data_ver(local, name) hidden_data_ver (local, name) | |
567 | #else | |
568 | # define libmvec_hidden_proto(name, attrs...) | |
569 | # define libmvec_hidden_tls_proto(name, attrs...) | |
570 | # define libmvec_hidden_def(name) | |
571 | # define libmvec_hidden_weak(name) | |
572 | # define libmvec_hidden_ver(local, name) | |
573 | # define libmvec_hidden_data_def(name) | |
574 | # define libmvec_hidden_data_weak(name) | |
575 | # define libmvec_hidden_data_ver(local, name) | |
576 | #endif | |
577 | ||
9cd47470 | 578 | #if IS_IN (libresolv) |
6f9d8e68 | 579 | # define libresolv_hidden_proto(name, attrs...) hidden_proto (name, ##attrs) |
699df45b JM |
580 | # define libresolv_hidden_tls_proto(name, attrs...) \ |
581 | hidden_tls_proto (name, ##attrs) | |
6f9d8e68 UD |
582 | # define libresolv_hidden_def(name) hidden_def (name) |
583 | # define libresolv_hidden_weak(name) hidden_weak (name) | |
584 | # define libresolv_hidden_ver(local, name) hidden_ver (local, name) | |
585 | # define libresolv_hidden_data_def(name) hidden_data_def (name) | |
586 | # define libresolv_hidden_data_weak(name) hidden_data_weak (name) | |
587 | # define libresolv_hidden_data_ver(local, name) hidden_data_ver (local, name) | |
588 | #else | |
589 | # define libresolv_hidden_proto(name, attrs...) | |
699df45b | 590 | # define libresolv_hidden_tls_proto(name, attrs...) |
6f9d8e68 UD |
591 | # define libresolv_hidden_def(name) |
592 | # define libresolv_hidden_weak(name) | |
593 | # define libresolv_hidden_ver(local, name) | |
594 | # define libresolv_hidden_data_def(name) | |
595 | # define libresolv_hidden_data_weak(name) | |
596 | # define libresolv_hidden_data_ver(local, name) | |
597 | #endif | |
598 | ||
9cd47470 | 599 | #if IS_IN (librt) |
a9564ae9 | 600 | # define librt_hidden_proto(name, attrs...) hidden_proto (name, ##attrs) |
699df45b JM |
601 | # define librt_hidden_tls_proto(name, attrs...) \ |
602 | hidden_tls_proto (name, ##attrs) | |
a9564ae9 UD |
603 | # define librt_hidden_def(name) hidden_def (name) |
604 | # define librt_hidden_weak(name) hidden_weak (name) | |
605 | # define librt_hidden_ver(local, name) hidden_ver (local, name) | |
606 | # define librt_hidden_data_def(name) hidden_data_def (name) | |
607 | # define librt_hidden_data_weak(name) hidden_data_weak (name) | |
608 | # define librt_hidden_data_ver(local, name) hidden_data_ver (local, name) | |
609 | #else | |
610 | # define librt_hidden_proto(name, attrs...) | |
699df45b | 611 | # define librt_hidden_tls_proto(name, attrs...) |
a9564ae9 UD |
612 | # define librt_hidden_def(name) |
613 | # define librt_hidden_weak(name) | |
614 | # define librt_hidden_ver(local, name) | |
615 | # define librt_hidden_data_def(name) | |
616 | # define librt_hidden_data_weak(name) | |
617 | # define librt_hidden_data_ver(local, name) | |
618 | #endif | |
619 | ||
9cd47470 | 620 | #if IS_IN (libdl) |
5f21997b | 621 | # define libdl_hidden_proto(name, attrs...) hidden_proto (name, ##attrs) |
699df45b JM |
622 | # define libdl_hidden_tls_proto(name, attrs...) \ |
623 | hidden_tls_proto (name, ##attrs) | |
5f21997b UD |
624 | # define libdl_hidden_def(name) hidden_def (name) |
625 | # define libdl_hidden_weak(name) hidden_weak (name) | |
626 | # define libdl_hidden_ver(local, name) hidden_ver (local, name) | |
627 | # define libdl_hidden_data_def(name) hidden_data_def (name) | |
628 | # define libdl_hidden_data_weak(name) hidden_data_weak (name) | |
629 | # define libdl_hidden_data_ver(local, name) hidden_data_ver (local, name) | |
630 | #else | |
631 | # define libdl_hidden_proto(name, attrs...) | |
699df45b | 632 | # define libdl_hidden_tls_proto(name, attrs...) |
5f21997b UD |
633 | # define libdl_hidden_def(name) |
634 | # define libdl_hidden_weak(name) | |
635 | # define libdl_hidden_ver(local, name) | |
636 | # define libdl_hidden_data_def(name) | |
637 | # define libdl_hidden_data_weak(name) | |
638 | # define libdl_hidden_data_ver(local, name) | |
639 | #endif | |
640 | ||
9cd47470 | 641 | #if IS_IN (libnss_files) |
44843eee | 642 | # define libnss_files_hidden_proto(name, attrs...) hidden_proto (name, ##attrs) |
699df45b JM |
643 | # define libnss_files_hidden_tls_proto(name, attrs...) \ |
644 | hidden_tls_proto (name, ##attrs) | |
44843eee UD |
645 | # define libnss_files_hidden_def(name) hidden_def (name) |
646 | # define libnss_files_hidden_weak(name) hidden_weak (name) | |
647 | # define libnss_files_hidden_ver(local, name) hidden_ver (local, name) | |
648 | # define libnss_files_hidden_data_def(name) hidden_data_def (name) | |
649 | # define libnss_files_hidden_data_weak(name) hidden_data_weak (name) | |
650 | # define libnss_files_hidden_data_ver(local, name) hidden_data_ver(local, name) | |
651 | #else | |
652 | # define libnss_files_hidden_proto(name, attrs...) | |
699df45b | 653 | # define libnss_files_hidden_tls_proto(name, attrs...) |
44843eee UD |
654 | # define libnss_files_hidden_def(name) |
655 | # define libnss_files_hidden_weak(name) | |
656 | # define libnss_files_hidden_ver(local, name) | |
657 | # define libnss_files_hidden_data_def(name) | |
658 | # define libnss_files_hidden_data_weak(name) | |
659 | # define libnss_files_hidden_data_ver(local, name) | |
660 | #endif | |
661 | ||
9cd47470 | 662 | #if IS_IN (libnsl) |
1d5cee23 | 663 | # define libnsl_hidden_proto(name, attrs...) hidden_proto (name, ##attrs) |
699df45b JM |
664 | # define libnsl_hidden_tls_proto(name, attrs...) \ |
665 | hidden_tls_proto (name, ##attrs) | |
1d5cee23 UD |
666 | # define libnsl_hidden_def(name) hidden_def (name) |
667 | # define libnsl_hidden_weak(name) hidden_weak (name) | |
668 | # define libnsl_hidden_ver(local, name) hidden_ver (local, name) | |
669 | # define libnsl_hidden_data_def(name) hidden_data_def (name) | |
670 | # define libnsl_hidden_data_weak(name) hidden_data_weak (name) | |
671 | # define libnsl_hidden_data_ver(local, name) hidden_data_ver (local, name) | |
672 | #else | |
673 | # define libnsl_hidden_proto(name, attrs...) | |
699df45b | 674 | # define libnsl_hidden_tls_proto(name, attrs...) |
1d5cee23 UD |
675 | # define libnsl_hidden_def(name) |
676 | # define libnsl_hidden_weak(name) | |
677 | # define libnsl_hidden_ver(local, name) | |
678 | # define libnsl_hidden_data_def(name) | |
679 | # define libnsl_hidden_data_weak(name) | |
680 | # define libnsl_hidden_data_ver(local, name) | |
681 | #endif | |
682 | ||
9cd47470 | 683 | #if IS_IN (libnss_nisplus) |
b31b32b3 | 684 | # define libnss_nisplus_hidden_proto(name, attrs...) hidden_proto (name, ##attrs) |
699df45b JM |
685 | # define libnss_nisplus_hidden_tls_proto(name, attrs...) \ |
686 | hidden_tls_proto (name, ##attrs) | |
b31b32b3 UD |
687 | # define libnss_nisplus_hidden_def(name) hidden_def (name) |
688 | # define libnss_nisplus_hidden_weak(name) hidden_weak (name) | |
689 | # define libnss_nisplus_hidden_ver(local, name) hidden_ver (local, name) | |
690 | # define libnss_nisplus_hidden_data_def(name) hidden_data_def (name) | |
691 | # define libnss_nisplus_hidden_data_weak(name) hidden_data_weak (name) | |
692 | # define libnss_nisplus_hidden_data_ver(local, name) hidden_data_ver (local, name) | |
693 | #else | |
694 | # define libnss_nisplus_hidden_proto(name, attrs...) | |
699df45b | 695 | # define libnss_nisplus_hidden_tls_proto(name, attrs...) |
b31b32b3 UD |
696 | # define libnss_nisplus_hidden_def(name) |
697 | # define libnss_nisplus_hidden_weak(name) | |
698 | # define libnss_nisplus_hidden_ver(local, name) | |
699 | # define libnss_nisplus_hidden_data_def(name) | |
700 | # define libnss_nisplus_hidden_data_weak(name) | |
701 | # define libnss_nisplus_hidden_data_ver(local, name) | |
702 | #endif | |
703 | ||
3ce1f295 UD |
704 | #define libc_hidden_builtin_proto(name, attrs...) libc_hidden_proto (name, ##attrs) |
705 | #define libc_hidden_builtin_def(name) libc_hidden_def (name) | |
706 | #define libc_hidden_builtin_weak(name) libc_hidden_weak (name) | |
707 | #define libc_hidden_builtin_ver(local, name) libc_hidden_ver (local, name) | |
708 | #ifdef __ASSEMBLER__ | |
709 | # define HIDDEN_BUILTIN_JUMPTARGET(name) HIDDEN_JUMPTARGET(name) | |
85dd1003 UD |
710 | #endif |
711 | ||
9cd47470 | 712 | #if IS_IN (libutil) |
b31b32b3 | 713 | # define libutil_hidden_proto(name, attrs...) hidden_proto (name, ##attrs) |
699df45b JM |
714 | # define libutil_hidden_tls_proto(name, attrs...) \ |
715 | hidden_tls_proto (name, ##attrs) | |
b31b32b3 UD |
716 | # define libutil_hidden_def(name) hidden_def (name) |
717 | # define libutil_hidden_weak(name) hidden_weak (name) | |
718 | # define libutil_hidden_ver(local, name) hidden_ver (local, name) | |
719 | # define libutil_hidden_data_def(name) hidden_data_def (name) | |
720 | # define libutil_hidden_data_weak(name) hidden_data_weak (name) | |
721 | # define libutil_hidden_data_ver(local, name) hidden_data_ver (local, name) | |
722 | #else | |
723 | # define libutil_hidden_proto(name, attrs...) | |
699df45b | 724 | # define libutil_hidden_tls_proto(name, attrs...) |
b31b32b3 UD |
725 | # define libutil_hidden_def(name) |
726 | # define libutil_hidden_weak(name) | |
727 | # define libutil_hidden_ver(local, name) | |
728 | # define libutil_hidden_data_def(name) | |
729 | # define libutil_hidden_data_weak(name) | |
730 | # define libutil_hidden_data_ver(local, name) | |
731 | #endif | |
732 | ||
b30542fb UD |
733 | /* Get some dirty hacks. */ |
734 | #include <symbol-hacks.h> | |
735 | ||
4a381a81 UD |
736 | /* Move compatibility symbols out of the way by placing them all in a |
737 | special section. */ | |
d3a4a571 UD |
738 | #ifndef __ASSEMBLER__ |
739 | # define attribute_compat_text_section \ | |
4a381a81 | 740 | __attribute__ ((section (".text.compat"))) |
d3a4a571 | 741 | # define attribute_compat_data_section \ |
4a381a81 | 742 | __attribute__ ((section (".data.compat"))) |
d3a4a571 UD |
743 | #else |
744 | # define compat_text_section .section ".text.compat", "ax"; | |
745 | # define compat_data_section .section ".data.compat", "aw"; | |
746 | #endif | |
4a381a81 | 747 | |
00980d84 SL |
748 | /* Helper / base macros for indirect function symbols. */ |
749 | #define __ifunc_resolver(type_name, name, expr, arg, init, classifier) \ | |
de659123 | 750 | classifier inhibit_stack_protector void *name##_ifunc (arg) \ |
425ce2ed | 751 | { \ |
00980d84 SL |
752 | init (); \ |
753 | __typeof (type_name) *res = expr; \ | |
425ce2ed | 754 | return res; \ |
00980d84 SL |
755 | } |
756 | ||
757 | #ifdef HAVE_GCC_IFUNC | |
758 | # define __ifunc(type_name, name, expr, arg, init) \ | |
759 | extern __typeof (type_name) name __attribute__ \ | |
760 | ((ifunc (#name "_ifunc"))); \ | |
761 | __ifunc_resolver (type_name, name, expr, arg, init, static) | |
762 | ||
763 | # define __ifunc_hidden(type_name, name, expr, arg, init) \ | |
764 | __ifunc (type_name, name, expr, arg, init) | |
765 | #else | |
766 | /* Gcc does not support __attribute__ ((ifunc (...))). Use the old behaviour | |
767 | as fallback. But keep in mind that the debug information for the ifunc | |
768 | resolver functions is not correct. It contains the ifunc'ed function as | |
769 | DW_AT_linkage_name. E.g. lldb uses this field and an inferior function | |
770 | call of the ifunc'ed function will fail due to "no matching function for | |
771 | call to ..." because the ifunc'ed function and the resolver function have | |
772 | different signatures. (Gcc support is disabled at least on a ppc64le | |
773 | Ubuntu 14.04 system.) */ | |
774 | ||
775 | # define __ifunc(type_name, name, expr, arg, init) \ | |
776 | extern __typeof (type_name) name; \ | |
777 | void *name##_ifunc (arg) __asm__ (#name); \ | |
778 | __ifunc_resolver (type_name, name, expr, arg, init,) \ | |
779 | __asm__ (".type " #name ", %gnu_indirect_function"); | |
780 | ||
781 | # define __ifunc_hidden(type_name, name, expr, arg, init) \ | |
782 | extern __typeof (type_name) __libc_##name; \ | |
783 | __ifunc (type_name, __libc_##name, expr, arg, init) \ | |
784 | strong_alias (__libc_##name, name); | |
785 | #endif /* !HAVE_GCC_IFUNC */ | |
786 | ||
787 | /* The following macros are used for indirect function symbols in libc.so. | |
788 | First of all, you need to have the function prototyped somewhere, | |
789 | say in foo.h: | |
790 | ||
791 | int foo (int __bar); | |
792 | ||
793 | If you have an implementation for foo which e.g. uses a special hardware | |
794 | feature which isn't available on all machines where this libc.so will be | |
795 | used but decideable if available at runtime e.g. via hwcaps, you can provide | |
796 | two or multiple implementations of foo: | |
797 | ||
798 | int __foo_default (int __bar) | |
799 | { | |
800 | return __bar; | |
801 | } | |
802 | ||
803 | int __foo_special (int __bar) | |
804 | { | |
805 | return __bar; | |
806 | } | |
807 | ||
808 | If your function foo has no libc_hidden_proto (foo) defined for PLT | |
809 | bypassing, you can use: | |
810 | ||
811 | #define INIT_ARCH() unsigned long int hwcap = __GLRO(dl_hwcap); | |
812 | ||
813 | libc_ifunc (foo, (hwcap & HWCAP_SPECIAL) ? __foo_special : __foo_default); | |
814 | ||
815 | This will define a resolver function for foo which returns __foo_special or | |
816 | __foo_default depending on your specified expression. Please note that you | |
817 | have to define a macro function INIT_ARCH before using libc_ifunc macro as | |
818 | it is called by the resolver function before evaluating the specified | |
819 | expression. In this example it is used to prepare the hwcap variable. | |
820 | The resolver function is assigned to an ifunc'ed symbol foo. Calls to foo | |
821 | from inside or outside of libc.so will be indirected by a PLT call. | |
822 | ||
823 | If your function foo has a libc_hidden_proto (foo) defined for PLT bypassing | |
824 | and calls to foo within libc.so should always go to one specific | |
825 | implementation of foo e.g. __foo_default then you have to add: | |
826 | ||
827 | __hidden_ver1 (__foo_default, __GI_foo, __foo_default); | |
828 | ||
829 | or a tweaked definition of libc_hidden_def macro after the __foo_default | |
830 | function definition. Calls to foo within libc.so will always go directly to | |
831 | __foo_default. Calls to foo from outside libc.so will be indirected by a | |
832 | PLT call to ifunc'ed symbol foo which you have to define in a separate | |
833 | compile unit: | |
834 | ||
835 | #define foo __redirect_foo | |
836 | #include <foo.h> | |
837 | #undef foo | |
838 | ||
839 | extern __typeof (__redirect_foo) __foo_default attribute_hidden; | |
840 | extern __typeof (__redirect_foo) __foo_special attribute_hidden; | |
841 | ||
842 | libc_ifunc_redirected (__redirect_foo, foo, | |
843 | (hwcap & HWCAP_SPECIAL) | |
844 | ? __foo_special | |
845 | : __foo_default); | |
846 | ||
847 | This will define the ifunc'ed symbol foo like above. The redirection of foo | |
848 | in header file is needed to omit an additional defintion of __GI_foo which | |
849 | would end in a linker error while linking libc.so. You have to specify | |
850 | __redirect_foo as first parameter which is used within libc_ifunc_redirected | |
851 | macro in conjunction with typeof to define the ifunc'ed symbol foo. | |
852 | ||
853 | If your function foo has a libc_hidden_proto (foo) defined and calls to foo | |
854 | within or from outside libc.so should go via ifunc'ed symbol, then you have | |
855 | to use: | |
856 | ||
857 | libc_ifunc_hidden (foo, foo, | |
858 | (hwcap & HWCAP_SPECIAL) | |
859 | ? __foo_special | |
860 | : __foo_default); | |
861 | libc_hidden_def (foo) | |
862 | ||
863 | The first parameter foo of libc_ifunc_hidden macro is used in the same way | |
864 | as for libc_ifunc_redirected macro. */ | |
865 | ||
866 | #define libc_ifunc(name, expr) __ifunc (name, name, expr, void, INIT_ARCH) | |
867 | ||
868 | #define libc_ifunc_redirected(redirected_name, name, expr) \ | |
869 | __ifunc (redirected_name, name, expr, void, INIT_ARCH) | |
870 | ||
871 | #define libc_ifunc_hidden(redirected_name, name, expr) \ | |
872 | __ifunc_hidden (redirected_name, name, expr, void, INIT_ARCH) | |
425ce2ed | 873 | |
9a1d2d45 UD |
874 | /* The body of the function is supposed to use __get_cpu_features |
875 | which will, if necessary, initialize the data first. */ | |
00980d84 SL |
876 | #define libm_ifunc_init() |
877 | #define libm_ifunc(name, expr) \ | |
878 | __ifunc (name, name, expr, void, libm_ifunc_init) | |
9a1d2d45 | 879 | |
85c2e611 AZ |
880 | /* Add the compiler optimization to inhibit loop transformation to library |
881 | calls. This is used to avoid recursive calls in memset and memmove | |
882 | default implementations. */ | |
883 | #ifdef HAVE_CC_INHIBIT_LOOP_TO_LIBCALL | |
884 | # define inhibit_loop_to_libcall \ | |
885 | __attribute__ ((__optimize__ ("-fno-tree-loop-distribute-patterns"))) | |
886 | #else | |
887 | # define inhibit_loop_to_libcall | |
888 | #endif | |
889 | ||
28f540f4 | 890 | #endif /* libc-symbols.h */ |