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) 1995-2018 Free Software Foundation, Inc.
4 This file is part of the GNU C Library.
5
6 The GNU C Library is free software; you can redistribute it and/or
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.
10
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
14 Lesser General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, see
18 <http://www.gnu.org/licenses/>. */
19
20#ifndef _LIBC_SYMBOLS_H
21#define _LIBC_SYMBOLS_H 1
22
23/* This file is included implicitly in the compilation of every source file,
24 using -include. It includes config.h. */
25
26/* Enable declarations of GNU extensions, since we are compiling them. */
27#define _GNU_SOURCE 1
28
29#ifdef MODULE_NAME
30
31/* Use `#if IS_IN (module)` to detect what component is being compiled. */
32#define PASTE_NAME1(a,b) a##b
33#define PASTE_NAME(a,b) PASTE_NAME1 (a,b)
34#define IN_MODULE PASTE_NAME (MODULE_, MODULE_NAME)
35#define IS_IN(lib) (IN_MODULE == MODULE_##lib)
36
37/* True if the current module is a versioned library. Versioned
38 library names culled from shlib-versions files are assigned a
39 MODULE_* value greater than MODULE_LIBS_BEGIN. */
40#define IS_IN_LIB (IN_MODULE > MODULE_LIBS_BEGIN)
41
42/* The testsuite, and some other ancillary code, should be compiled against
43 as close an approximation to the installed headers as possible.
44 Defining this symbol disables most internal-use-only declarations
45 provided by this header, and all those provided by other internal
46 wrapper headers. */
47#if IS_IN (testsuite) || defined IS_IN_build || defined __cplusplus
48# define _ISOMAC 1
49#endif
50
51#else
52/* The generation process for a few files created very early in the
53 build (notably libc-modules.h itself) involves preprocessing this
54 header without defining MODULE_NAME. Under these conditions,
55 internal declarations (especially from config.h) must be visible,
56 but IS_IN should always evaluate as false. */
57# define IS_IN(lib) 0
58# define IS_IN_LIB 0
59# define IN_MODULE (-1)
60#endif
61
62#ifndef _ISOMAC
63
64/* This is defined for the compilation of all C library code. features.h
65 tests this to avoid inclusion of stubs.h while compiling the library,
66 before stubs.h has been generated. Some library code that is shared
67 with other packages also tests this symbol to see if it is being
68 compiled as part of the C library. We must define this before including
69 config.h, because it makes some definitions conditional on whether libc
70 itself is being compiled, or just some generator program. */
71#define _LIBC 1
72
73/* Some files must be compiled with optimization on. */
74#if !defined __ASSEMBLER__ && !defined __OPTIMIZE__
75# error "glibc cannot be compiled without optimization"
76#endif
77
78/* -ffast-math cannot be applied to the C library, as it alters the ABI.
79 Some test components that use -ffast-math are currently not part of
80 IS_IN (testsuite) for technical reasons, so we have a secondary override. */
81#if defined __FAST_MATH__ && !defined TEST_FAST_MATH
82# error "glibc must not be compiled with -ffast-math"
83#endif
84
85#include <config.h>
86
87/* When PIC is defined and SHARED isn't defined, we are building PIE
88 by default. */
89#if defined PIC && !defined SHARED
90# define BUILD_PIE_DEFAULT 1
91#else
92# define BUILD_PIE_DEFAULT 0
93#endif
94
95/* Define this for the benefit of portable GNU code that wants to check it.
96 Code that checks with #if will not #include <config.h> again, since we've
97 already done it (and this file is implicitly included in every compile,
98 via -include). Code that checks with #ifdef will #include <config.h>,
99 but that file should always be idempotent (i.e., it's just #define/#undef
100 and nothing else anywhere should be changing the macro state it touches),
101 so it's harmless. */
102#define HAVE_CONFIG_H 0
103
104/* Define these macros for the benefit of portable GNU code that wants to check
105 them. Of course, STDC_HEADERS is never false when building libc! */
106#define STDC_HEADERS 1
107#define HAVE_MBSTATE_T 1
108#define HAVE_MBSRTOWCS 1
109#define HAVE_LIBINTL_H 1
110#define HAVE_WCTYPE_H 1
111#define HAVE_ISWCTYPE 1
112#define ENABLE_NLS 1
113
114/* The symbols in all the user (non-_) macros are C symbols. */
115
116#ifndef __SYMBOL_PREFIX
117# define __SYMBOL_PREFIX
118#endif
119
120#ifndef C_SYMBOL_NAME
121# define C_SYMBOL_NAME(name) name
122#endif
123
124#ifndef ASM_LINE_SEP
125# define ASM_LINE_SEP ;
126#endif
127
128#ifndef __attribute_copy__
129/* Provide an empty definition when cdefs.h is not included. */
130# define __attribute_copy__(arg)
131#endif
132
133#ifndef __ASSEMBLER__
134/* GCC understands weak symbols and aliases; use its interface where
135 possible, instead of embedded assembly language. */
136
137/* Define ALIASNAME as a strong alias for NAME. */
138# define strong_alias(name, aliasname) _strong_alias(name, aliasname)
139# define _strong_alias(name, aliasname) \
140 extern __typeof (name) aliasname __attribute__ ((alias (#name))) \
141 __attribute_copy__ (name);
142
143/* This comes between the return type and function name in
144 a function definition to make that definition weak. */
145# define weak_function __attribute__ ((weak))
146# define weak_const_function __attribute__ ((weak, __const__))
147
148/* Define ALIASNAME as a weak alias for NAME.
149 If weak aliases are not available, this defines a strong alias. */
150# define weak_alias(name, aliasname) _weak_alias (name, aliasname)
151# define _weak_alias(name, aliasname) \
152 extern __typeof (name) aliasname __attribute__ ((weak, alias (#name))) \
153 __attribute_copy__ (name);
154
155/* Same as WEAK_ALIAS, but mark symbol as hidden. */
156# define weak_hidden_alias(name, aliasname) \
157 _weak_hidden_alias (name, aliasname)
158# define _weak_hidden_alias(name, aliasname) \
159 extern __typeof (name) aliasname \
160 __attribute__ ((weak, alias (#name), __visibility__ ("hidden"))) \
161 __attribute_copy__ (name);
162
163/* Declare SYMBOL as weak undefined symbol (resolved to 0 if not defined). */
164# define weak_extern(symbol) _weak_extern (weak symbol)
165# define _weak_extern(expr) _Pragma (#expr)
166
167/* In shared builds, the expression call_function_static_weak
168 (FUNCTION-SYMBOL, ARGUMENTS) invokes FUNCTION-SYMBOL (an
169 identifier) unconditionally, with the (potentially empty) argument
170 list ARGUMENTS. In static builds, if FUNCTION-SYMBOL has a
171 definition, the function is invoked as before; if FUNCTION-SYMBOL
172 is NULL, no call is performed. */
173# ifdef SHARED
174# define call_function_static_weak(func, ...) func (__VA_ARGS__)
175# else /* !SHARED */
176# define call_function_static_weak(func, ...) \
177 ({ \
178 extern __typeof__ (func) func weak_function; \
179 (func != NULL ? func (__VA_ARGS__) : (void)0); \
180 })
181# endif
182
183#else /* __ASSEMBLER__ */
184
185# ifdef HAVE_ASM_SET_DIRECTIVE
186# define strong_alias(original, alias) \
187 .globl C_SYMBOL_NAME (alias) ASM_LINE_SEP \
188 .set C_SYMBOL_NAME (alias),C_SYMBOL_NAME (original)
189# define strong_data_alias(original, alias) strong_alias(original, alias)
190# else
191# define strong_alias(original, alias) \
192 .globl C_SYMBOL_NAME (alias) ASM_LINE_SEP \
193 C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original)
194# define strong_data_alias(original, alias) strong_alias(original, alias)
195# endif
196
197# define weak_alias(original, alias) \
198 .weak C_SYMBOL_NAME (alias) ASM_LINE_SEP \
199 C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original)
200
201# define weak_extern(symbol) \
202 .weak C_SYMBOL_NAME (symbol)
203
204#endif /* __ASSEMBLER__ */
205
206/* Determine the return address. */
207#define RETURN_ADDRESS(nr) \
208 __builtin_extract_return_addr (__builtin_return_address (nr))
209
210/* When a reference to SYMBOL is encountered, the linker will emit a
211 warning message MSG. */
212/* We want the .gnu.warning.SYMBOL section to be unallocated. */
213#define __make_section_unallocated(section_string) \
214 asm (".section " section_string "\n\t.previous");
215
216/* Tacking on "\n\t#" to the section name makes gcc put it's bogus
217 section attributes on what looks like a comment to the assembler. */
218#ifdef HAVE_SECTION_QUOTES
219# define __sec_comment "\"\n\t#\""
220#else
221# define __sec_comment "\n\t#"
222#endif
223#define link_warning(symbol, msg) \
224 __make_section_unallocated (".gnu.warning." #symbol) \
225 static const char __evoke_link_warning_##symbol[] \
226 __attribute__ ((used, section (".gnu.warning." #symbol __sec_comment))) \
227 = msg;
228
229/* A canned warning for sysdeps/stub functions. */
230#define stub_warning(name) \
231 __make_section_unallocated (".gnu.glibc-stub." #name) \
232 link_warning (name, #name " is not implemented and will always fail")
233
234/* Warning for linking functions calling dlopen into static binaries. */
235#ifdef SHARED
236#define static_link_warning(name)
237#else
238#define static_link_warning(name) static_link_warning1(name)
239#define static_link_warning1(name) \
240 link_warning(name, "Using '" #name "' in statically linked applications \
241requires at runtime the shared libraries from the glibc version used \
242for linking")
243#endif
244
245/* Resource Freeing Hooks:
246
247 Normally a process exits and the OS cleans up any allocated
248 memory. However, when tooling like mtrace or valgrind is monitoring
249 the process we need to free all resources that are part of the
250 process in order to provide the consistency required to track
251 memory leaks.
252
253 A single public API exists and is __libc_freeres(), and this is used
254 by applications like valgrind to freee resouces.
255
256 There are 3 cases:
257
258 (a) __libc_freeres
259
260 In this case all you need to do is define the freeing routine:
261
262 foo.c:
263 libfoo_freeres_fn (foo_freeres)
264 {
265 complex_free (mem);
266 }
267
268 This ensures the function is called at the right point to free
269 resources.
270
271 (b) __libc_freeres_ptr
272
273 The framework for (a) iterates over the list of pointers-to-free
274 in (b) and frees them.
275
276 foo.c:
277 libc_freeres_ptr (static char *foo_buffer);
278
279 Freeing these resources alaways happens last and is equivalent
280 to registering a function that does 'free (foo_buffer)'.
281
282 (c) Explicit lists of free routines to call or objects to free.
283
284 It is the intended goal to remove (a) and (b) which have some
285 non-determinism based on link order, and instead use explicit
286 lists of functions and frees to resolve cleanup ordering issues
287 and make it easy to debug and maintain.
288
289 As of today the following subsystems use (c):
290
291 Per-thread cleanup:
292 * malloc/thread-freeres.c
293
294 libdl cleanup:
295 * dlfcn/dlfreeres.c
296
297 libpthread cleanup:
298 * nptl/nptlfreeres.c
299
300 So if you need any shutdown routines to run you should add them
301 directly to the appropriate subsystem's shutdown list. */
302
303/* Resource pointers to free in libc.so. */
304#define libc_freeres_ptr(decl) \
305 __make_section_unallocated ("__libc_freeres_ptrs, \"aw\", %nobits") \
306 decl __attribute__ ((section ("__libc_freeres_ptrs" __sec_comment)))
307
308/* Resource freeing functions from libc.so go in this section. */
309#define __libc_freeres_fn_section \
310 __attribute__ ((section ("__libc_freeres_fn")))
311
312/* Resource freeing functions for libc.so. */
313#define libc_freeres_fn(name) \
314 static void name (void) __attribute_used__ __libc_freeres_fn_section; \
315 text_set_element (__libc_subfreeres, name); \
316 static void name (void)
317
318/* Declare SYMBOL to be TYPE (`function' or `object') of SIZE bytes
319 alias to ORIGINAL, when the assembler supports such declarations
320 (such as in ELF).
321 This is only necessary when defining something in assembly, or playing
322 funny alias games where the size should be other than what the compiler
323 thinks it is. */
324#define declare_symbol_alias(symbol, original, type, size) \
325 declare_symbol_alias_1 (symbol, original, type, size)
326#ifdef __ASSEMBLER__
327# define declare_symbol_alias_1(symbol, original, type, size) \
328 strong_alias (original, symbol); \
329 .type C_SYMBOL_NAME (symbol), %##type; \
330 .size C_SYMBOL_NAME (symbol), size
331#else /* Not __ASSEMBLER__. */
332# define declare_symbol_alias_1(symbol, original, type, size) \
333 asm (".globl " __SYMBOL_PREFIX #symbol \
334 "\n\t" declare_symbol_alias_1_alias (symbol, original) \
335 "\n\t.type " __SYMBOL_PREFIX #symbol ", " \
336 "%" #type \
337 "\n\t.size " __SYMBOL_PREFIX #symbol ", " #size);
338# ifdef HAVE_ASM_SET_DIRECTIVE
339# define declare_symbol_alias_1_alias(symbol, original) \
340 ".set " __SYMBOL_PREFIX #symbol ", " __SYMBOL_PREFIX #original
341# else
342# define declare_symbol_alias_1_alias(symbol, original) \
343 __SYMBOL_PREFIX #symbol " = " __SYMBOL_PREFIX #original
344# endif /* HAVE_ASM_SET_DIRECTIVE */
345#endif /* __ASSEMBLER__ */
346
347
348/*
349
350*/
351
352/* Symbol set support macros. */
353
354/* Make SYMBOL, which is in the text segment, an element of SET. */
355#define text_set_element(set, symbol) _elf_set_element(set, symbol)
356/* Make SYMBOL, which is in the data segment, an element of SET. */
357#define data_set_element(set, symbol) _elf_set_element(set, symbol)
358/* Make SYMBOL, which is in the bss segment, an element of SET. */
359#define bss_set_element(set, symbol) _elf_set_element(set, symbol)
360
361/* These are all done the same way in ELF.
362 There is a new section created for each set. */
363#ifdef SHARED
364/* When building a shared library, make the set section writable,
365 because it will need to be relocated at run time anyway. */
366# define _elf_set_element(set, symbol) \
367 static const void *__elf_set_##set##_element_##symbol##__ \
368 __attribute__ ((used, section (#set))) = &(symbol)
369#else
370# define _elf_set_element(set, symbol) \
371 static const void *const __elf_set_##set##_element_##symbol##__ \
372 __attribute__ ((used, section (#set))) = &(symbol)
373#endif
374
375/* Define SET as a symbol set. This may be required (it is in a.out) to
376 be able to use the set's contents. */
377#define symbol_set_define(set) symbol_set_declare(set)
378
379/* Declare SET for use in this module, if defined in another module.
380 In a shared library, this is always local to that shared object.
381 For static linking, the set might be wholly absent and so we use
382 weak references. */
383#define symbol_set_declare(set) \
384 extern char const __start_##set[] __symbol_set_attribute; \
385 extern char const __stop_##set[] __symbol_set_attribute;
386#ifdef SHARED
387# define __symbol_set_attribute attribute_hidden
388#else
389# define __symbol_set_attribute __attribute__ ((weak))
390#endif
391
392/* Return a pointer (void *const *) to the first element of SET. */
393#define symbol_set_first_element(set) ((void *const *) (&__start_##set))
394
395/* Return true iff PTR (a void *const *) has been incremented
396 past the last element in SET. */
397#define symbol_set_end_p(set, ptr) ((ptr) >= (void *const *) &__stop_##set)
398
399/* Use symbol_version_reference to specify the version a symbol
400 reference should link to. Use symbol_version or
401 default_symbol_version for the definition of a versioned symbol.
402 The difference is that the latter is a no-op in non-shared
403 builds. */
404#ifdef __ASSEMBLER__
405# define symbol_version_reference(real, name, version) \
406 .symver real, name##@##version
407#else /* !__ASSEMBLER__ */
408# define symbol_version_reference(real, name, version) \
409 __asm__ (".symver " #real "," #name "@" #version)
410#endif
411
412#ifdef SHARED
413# define symbol_version(real, name, version) \
414 symbol_version_reference(real, name, version)
415# define default_symbol_version(real, name, version) \
416 _default_symbol_version(real, name, version)
417# ifdef __ASSEMBLER__
418# define _default_symbol_version(real, name, version) \
419 .symver real, name##@##@##version
420# else
421# define _default_symbol_version(real, name, version) \
422 __asm__ (".symver " #real "," #name "@@" #version)
423# endif
424#else
425# define symbol_version(real, name, version)
426# define default_symbol_version(real, name, version) \
427 strong_alias(real, name)
428#endif
429
430#if defined SHARED || defined LIBC_NONSHARED \
431 || (BUILD_PIE_DEFAULT && IS_IN (libc))
432# define attribute_hidden __attribute__ ((visibility ("hidden")))
433#else
434# define attribute_hidden
435#endif
436
437#define attribute_tls_model_ie __attribute__ ((tls_model ("initial-exec")))
438
439#define attribute_relro __attribute__ ((section (".data.rel.ro")))
440
441
442/* Used to disable stack protection in sensitive places, like ifunc
443 resolvers and early static TLS init. */
444#ifdef HAVE_CC_NO_STACK_PROTECTOR
445# define inhibit_stack_protector \
446 __attribute__ ((__optimize__ ("-fno-stack-protector")))
447#else
448# define inhibit_stack_protector
449#endif
450
451/* The following macros are used for PLT bypassing within libc.so
452 (and if needed other libraries similarly).
453 First of all, you need to have the function prototyped somewhere,
454 say in foo/foo.h:
455
456 int foo (int __bar);
457
458 If calls to foo within libc.so should always go to foo defined in libc.so,
459 then in include/foo.h you add:
460
461 libc_hidden_proto (foo)
462
463 line and after the foo function definition:
464
465 int foo (int __bar)
466 {
467 return __bar;
468 }
469 libc_hidden_def (foo)
470
471 or
472
473 int foo (int __bar)
474 {
475 return __bar;
476 }
477 libc_hidden_weak (foo)
478
479 Similarly for global data. If references to foo within libc.so should
480 always go to foo defined in libc.so, then in include/foo.h you add:
481
482 libc_hidden_proto (foo)
483
484 line and after foo's definition:
485
486 int foo = INITIAL_FOO_VALUE;
487 libc_hidden_data_def (foo)
488
489 or
490
491 int foo = INITIAL_FOO_VALUE;
492 libc_hidden_data_weak (foo)
493
494 If foo is normally just an alias (strong or weak) to some other function,
495 you should use the normal strong_alias first, then add libc_hidden_def
496 or libc_hidden_weak:
497
498 int baz (int __bar)
499 {
500 return __bar;
501 }
502 strong_alias (baz, foo)
503 libc_hidden_weak (foo)
504
505 If the function should be internal to multiple objects, say ld.so and
506 libc.so, the best way is to use:
507
508 #if IS_IN (libc) || IS_IN (rtld)
509 hidden_proto (foo)
510 #endif
511
512 in include/foo.h and the normal macros at all function definitions
513 depending on what DSO they belong to.
514
515 If versioned_symbol macro is used to define foo,
516 libc_hidden_ver macro should be used, as in:
517
518 int __real_foo (int __bar)
519 {
520 return __bar;
521 }
522 versioned_symbol (libc, __real_foo, foo, GLIBC_2_1);
523 libc_hidden_ver (__real_foo, foo) */
524
525#if defined SHARED && !defined NO_HIDDEN
526# ifndef __ASSEMBLER__
527# define __hidden_proto_hiddenattr(attrs...) \
528 __attribute__ ((visibility ("hidden"), ##attrs))
529# define hidden_proto(name, attrs...) \
530 __hidden_proto (name, , __GI_##name, ##attrs)
531# define hidden_tls_proto(name, attrs...) \
532 __hidden_proto (name, __thread, __GI_##name, ##attrs)
533# define __hidden_proto(name, thread, internal, attrs...) \
534 extern thread __typeof (name) name __asm__ (__hidden_asmname (#internal)) \
535 __hidden_proto_hiddenattr (attrs);
536# define __hidden_asmname(name) \
537 __hidden_asmname1 (__USER_LABEL_PREFIX__, name)
538# define __hidden_asmname1(prefix, name) __hidden_asmname2(prefix, name)
539# define __hidden_asmname2(prefix, name) #prefix name
540# define __hidden_ver1(local, internal, name) \
541 __hidden_ver2 (, local, internal, name)
542# define __hidden_ver2(thread, local, internal, name) \
543 extern thread __typeof (name) __EI_##name \
544 __asm__(__hidden_asmname (#internal)); \
545 extern thread __typeof (name) __EI_##name \
546 __attribute__((alias (__hidden_asmname (#local)))) \
547 __attribute_copy__ (name)
548# define hidden_ver(local, name) __hidden_ver1(local, __GI_##name, name);
549# define hidden_data_ver(local, name) hidden_ver(local, name)
550# define hidden_def(name) __hidden_ver1(__GI_##name, name, name);
551# define hidden_data_def(name) hidden_def(name)
552# define hidden_tls_def(name) \
553 __hidden_ver2 (__thread, __GI_##name, name, name);
554# define hidden_weak(name) \
555 __hidden_ver1(__GI_##name, name, name) __attribute__((weak));
556# define hidden_data_weak(name) hidden_weak(name)
557# define hidden_nolink(name, lib, version) \
558 __hidden_nolink1 (__GI_##name, __EI_##name, name, VERSION_##lib##_##version)
559# define __hidden_nolink1(local, internal, name, version) \
560 __hidden_nolink2 (local, internal, name, version)
561# define __hidden_nolink2(local, internal, name, version) \
562 extern __typeof (name) internal __attribute__ ((alias (#local))) \
563 __attribute_copy__ (name); \
564 __hidden_nolink3 (local, internal, #name "@" #version)
565# define __hidden_nolink3(local, internal, vername) \
566 __asm__ (".symver " #internal ", " vername);
567# else
568/* For assembly, we need to do the opposite of what we do in C:
569 in assembly gcc __REDIRECT stuff is not in place, so functions
570 are defined by its normal name and we need to create the
571 __GI_* alias to it, in C __REDIRECT causes the function definition
572 to use __GI_* name and we need to add alias to the real name.
573 There is no reason to use hidden_weak over hidden_def in assembly,
574 but we provide it for consistency with the C usage.
575 hidden_proto doesn't make sense for assembly but the equivalent
576 is to call via the HIDDEN_JUMPTARGET macro instead of JUMPTARGET. */
577# define hidden_def(name) strong_alias (name, __GI_##name)
578# define hidden_weak(name) hidden_def (name)
579# define hidden_ver(local, name) strong_alias (local, __GI_##name)
580# define hidden_data_def(name) strong_data_alias (name, __GI_##name)
581# define hidden_tls_def(name) hidden_data_def (name)
582# define hidden_data_weak(name) hidden_data_def (name)
583# define hidden_data_ver(local, name) strong_data_alias (local, __GI_##name)
584# define HIDDEN_JUMPTARGET(name) __GI_##name
585# endif
586#else
587# ifndef __ASSEMBLER__
588# if !defined SHARED && IS_IN (libc) && !defined LIBC_NONSHARED \
589 && (!defined PIC || !defined NO_HIDDEN_EXTERN_FUNC_IN_PIE) \
590 && !defined NO_HIDDEN
591# define __hidden_proto_hiddenattr(attrs...) \
592 __attribute__ ((visibility ("hidden"), ##attrs))
593# define hidden_proto(name, attrs...) \
594 __hidden_proto (name, , name, ##attrs)
595# define hidden_tls_proto(name, attrs...) \
596 __hidden_proto (name, __thread, name, ##attrs)
597# define __hidden_proto(name, thread, internal, attrs...) \
598 extern thread __typeof (name) name __hidden_proto_hiddenattr (attrs);
599# else
600# define hidden_proto(name, attrs...)
601# define hidden_tls_proto(name, attrs...)
602# endif
603# else
604# define HIDDEN_JUMPTARGET(name) JUMPTARGET(name)
605# endif /* Not __ASSEMBLER__ */
606# define hidden_weak(name)
607# define hidden_def(name)
608# define hidden_ver(local, name)
609# define hidden_data_weak(name)
610# define hidden_data_def(name)
611# define hidden_tls_def(name)
612# define hidden_data_ver(local, name)
613# define hidden_nolink(name, lib, version)
614#endif
615
616#if IS_IN (libc)
617# define libc_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
618# define libc_hidden_tls_proto(name, attrs...) hidden_tls_proto (name, ##attrs)
619# define libc_hidden_def(name) hidden_def (name)
620# define libc_hidden_weak(name) hidden_weak (name)
621# ifdef LINK_OBSOLETE_RPC
622 /* libc_hidden_nolink_sunrpc should only get used in sunrpc code. */
623# define libc_hidden_nolink_sunrpc(name, version) hidden_def (name)
624# else
625# define libc_hidden_nolink_sunrpc(name, version) hidden_nolink (name, libc, version)
626# endif
627# define libc_hidden_ver(local, name) hidden_ver (local, name)
628# define libc_hidden_data_def(name) hidden_data_def (name)
629# define libc_hidden_tls_def(name) hidden_tls_def (name)
630# define libc_hidden_data_weak(name) hidden_data_weak (name)
631# define libc_hidden_data_ver(local, name) hidden_data_ver (local, name)
632#else
633# define libc_hidden_proto(name, attrs...)
634# define libc_hidden_tls_proto(name, attrs...)
635# define libc_hidden_def(name)
636# define libc_hidden_weak(name)
637# define libc_hidden_ver(local, name)
638# define libc_hidden_data_def(name)
639# define libc_hidden_tls_def(name)
640# define libc_hidden_data_weak(name)
641# define libc_hidden_data_ver(local, name)
642#endif
643
644#if IS_IN (rtld) && !defined NO_RTLD_HIDDEN
645# define rtld_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
646# define rtld_hidden_tls_proto(name, attrs...) hidden_tls_proto (name, ##attrs)
647# define rtld_hidden_def(name) hidden_def (name)
648# define rtld_hidden_weak(name) hidden_weak (name)
649# define rtld_hidden_ver(local, name) hidden_ver (local, name)
650# define rtld_hidden_data_def(name) hidden_data_def (name)
651# define rtld_hidden_tls_def(name) hidden_tls_def (name)
652# define rtld_hidden_data_weak(name) hidden_data_weak (name)
653# define rtld_hidden_data_ver(local, name) hidden_data_ver (local, name)
654#else
655# define rtld_hidden_proto(name, attrs...)
656# define rtld_hidden_tls_proto(name, attrs...)
657# define rtld_hidden_def(name)
658# define rtld_hidden_weak(name)
659# define rtld_hidden_ver(local, name)
660# define rtld_hidden_data_def(name)
661# define rtld_hidden_tls_def(name)
662# define rtld_hidden_data_weak(name)
663# define rtld_hidden_data_ver(local, name)
664#endif
665
666#if IS_IN (libm)
667# define libm_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
668# define libm_hidden_tls_proto(name, attrs...) hidden_tls_proto (name, ##attrs)
669# define libm_hidden_def(name) hidden_def (name)
670# define libm_hidden_weak(name) hidden_weak (name)
671# define libm_hidden_ver(local, name) hidden_ver (local, name)
672# define libm_hidden_data_def(name) hidden_data_def (name)
673# define libm_hidden_tls_def(name) hidden_tls_def (name)
674# define libm_hidden_data_weak(name) hidden_data_weak (name)
675# define libm_hidden_data_ver(local, name) hidden_data_ver (local, name)
676#else
677# define libm_hidden_proto(name, attrs...)
678# define libm_hidden_tls_proto(name, attrs...)
679# define libm_hidden_def(name)
680# define libm_hidden_weak(name)
681# define libm_hidden_ver(local, name)
682# define libm_hidden_data_def(name)
683# define libm_hidden_tls_def(name)
684# define libm_hidden_data_weak(name)
685# define libm_hidden_data_ver(local, name)
686#endif
687
688#if IS_IN (libmvec)
689# define libmvec_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
690# define libmvec_hidden_tls_proto(name, attrs...) hidden_tls_proto (name, ##attrs)
691# define libmvec_hidden_def(name) hidden_def (name)
692# define libmvec_hidden_weak(name) hidden_weak (name)
693# define libmvec_hidden_ver(local, name) hidden_ver (local, name)
694# define libmvec_hidden_data_def(name) hidden_data_def (name)
695# define libmvec_hidden_tls_def(name) hidden_tls_def (name)
696# define libmvec_hidden_data_weak(name) hidden_data_weak (name)
697# define libmvec_hidden_data_ver(local, name) hidden_data_ver (local, name)
698#else
699# define libmvec_hidden_proto(name, attrs...)
700# define libmvec_hidden_tls_proto(name, attrs...)
701# define libmvec_hidden_def(name)
702# define libmvec_hidden_weak(name)
703# define libmvec_hidden_ver(local, name)
704# define libmvec_hidden_data_def(name)
705# define libmvec_hidden_tls_def(name)
706# define libmvec_hidden_data_weak(name)
707# define libmvec_hidden_data_ver(local, name)
708#endif
709
710#if IS_IN (libresolv)
711# define libresolv_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
712# define libresolv_hidden_tls_proto(name, attrs...) \
713 hidden_tls_proto (name, ##attrs)
714# define libresolv_hidden_def(name) hidden_def (name)
715# define libresolv_hidden_weak(name) hidden_weak (name)
716# define libresolv_hidden_ver(local, name) hidden_ver (local, name)
717# define libresolv_hidden_data_def(name) hidden_data_def (name)
718# define libresolv_hidden_tls_def(name) hidden_tls_def (name)
719# define libresolv_hidden_data_weak(name) hidden_data_weak (name)
720# define libresolv_hidden_data_ver(local, name) hidden_data_ver (local, name)
721#else
722# define libresolv_hidden_proto(name, attrs...)
723# define libresolv_hidden_tls_proto(name, attrs...)
724# define libresolv_hidden_def(name)
725# define libresolv_hidden_weak(name)
726# define libresolv_hidden_ver(local, name)
727# define libresolv_hidden_data_def(name)
728# define libresolv_hidden_tls_def(name)
729# define libresolv_hidden_data_weak(name)
730# define libresolv_hidden_data_ver(local, name)
731#endif
732
733#if IS_IN (librt)
734# define librt_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
735# define librt_hidden_tls_proto(name, attrs...) \
736 hidden_tls_proto (name, ##attrs)
737# define librt_hidden_def(name) hidden_def (name)
738# define librt_hidden_weak(name) hidden_weak (name)
739# define librt_hidden_ver(local, name) hidden_ver (local, name)
740# define librt_hidden_data_def(name) hidden_data_def (name)
741# define librt_hidden_tls_def(name) hidden_tls_def (name)
742# define librt_hidden_data_weak(name) hidden_data_weak (name)
743# define librt_hidden_data_ver(local, name) hidden_data_ver (local, name)
744#else
745# define librt_hidden_proto(name, attrs...)
746# define librt_hidden_tls_proto(name, attrs...)
747# define librt_hidden_def(name)
748# define librt_hidden_weak(name)
749# define librt_hidden_ver(local, name)
750# define librt_hidden_data_def(name)
751# define librt_hidden_tls_def(name)
752# define librt_hidden_data_weak(name)
753# define librt_hidden_data_ver(local, name)
754#endif
755
756#if IS_IN (libdl)
757# define libdl_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
758# define libdl_hidden_tls_proto(name, attrs...) \
759 hidden_tls_proto (name, ##attrs)
760# define libdl_hidden_def(name) hidden_def (name)
761# define libdl_hidden_weak(name) hidden_weak (name)
762# define libdl_hidden_ver(local, name) hidden_ver (local, name)
763# define libdl_hidden_data_def(name) hidden_data_def (name)
764# define libdl_hidden_tls_def(name) hidden_tls_def (name)
765# define libdl_hidden_data_weak(name) hidden_data_weak (name)
766# define libdl_hidden_data_ver(local, name) hidden_data_ver (local, name)
767#else
768# define libdl_hidden_proto(name, attrs...)
769# define libdl_hidden_tls_proto(name, attrs...)
770# define libdl_hidden_def(name)
771# define libdl_hidden_weak(name)
772# define libdl_hidden_ver(local, name)
773# define libdl_hidden_data_def(name)
774# define libdl_hidden_tls_def(name)
775# define libdl_hidden_data_weak(name)
776# define libdl_hidden_data_ver(local, name)
777#endif
778
779#if IS_IN (libnss_files)
780# define libnss_files_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
781# define libnss_files_hidden_tls_proto(name, attrs...) \
782 hidden_tls_proto (name, ##attrs)
783# define libnss_files_hidden_def(name) hidden_def (name)
784# define libnss_files_hidden_weak(name) hidden_weak (name)
785# define libnss_files_hidden_ver(local, name) hidden_ver (local, name)
786# define libnss_files_hidden_data_def(name) hidden_data_def (name)
787# define libnss_files_hidden_tls_def(name) hidden_tls_def (name)
788# define libnss_files_hidden_data_weak(name) hidden_data_weak (name)
789# define libnss_files_hidden_data_ver(local, name) hidden_data_ver(local, name)
790#else
791# define libnss_files_hidden_proto(name, attrs...)
792# define libnss_files_hidden_tls_proto(name, attrs...)
793# define libnss_files_hidden_def(name)
794# define libnss_files_hidden_weak(name)
795# define libnss_files_hidden_ver(local, name)
796# define libnss_files_hidden_data_def(name)
797# define libnss_files_hidden_tls_def(name)
798# define libnss_files_hidden_data_weak(name)
799# define libnss_files_hidden_data_ver(local, name)
800#endif
801
802#if IS_IN (libnsl)
803# define libnsl_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
804# define libnsl_hidden_tls_proto(name, attrs...) \
805 hidden_tls_proto (name, ##attrs)
806# ifdef LINK_OBSOLETE_NSL
807 /* libnsl_hidden_nolink should only get used in libnsl code. */
808# define libnsl_hidden_nolink_def(name, version) libnsl_hidden_def (name)
809# else
810# define libnsl_hidden_nolink_def(name, version) hidden_nolink (name, libnsl, version)
811# endif
812# define libnsl_hidden_def(name) hidden_def (name)
813# define libnsl_hidden_weak(name) hidden_weak (name)
814# define libnsl_hidden_ver(local, name) hidden_ver (local, name)
815# define libnsl_hidden_data_def(name) hidden_data_def (name)
816# define libnsl_hidden_tls_def(name) hidden_tls_def (name)
817# define libnsl_hidden_data_weak(name) hidden_data_weak (name)
818# define libnsl_hidden_data_ver(local, name) hidden_data_ver (local, name)
819#else
820# define libnsl_hidden_proto(name, attrs...)
821# define libnsl_hidden_tls_proto(name, attrs...)
822# define libnsl_hidden_def(name)
823# define libnsl_hidden_weak(name)
824# define libnsl_hidden_ver(local, name)
825# define libnsl_hidden_data_def(name)
826# define libnsl_hidden_tls_def(name)
827# define libnsl_hidden_data_weak(name)
828# define libnsl_hidden_data_ver(local, name)
829#endif
830
831#if IS_IN (libnss_nisplus)
832# define libnss_nisplus_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
833# define libnss_nisplus_hidden_tls_proto(name, attrs...) \
834 hidden_tls_proto (name, ##attrs)
835# define libnss_nisplus_hidden_def(name) hidden_def (name)
836# define libnss_nisplus_hidden_weak(name) hidden_weak (name)
837# define libnss_nisplus_hidden_ver(local, name) hidden_ver (local, name)
838# define libnss_nisplus_hidden_data_def(name) hidden_data_def (name)
839# define libnss_nisplus_hidden_tls_def(name) hidden_tls_def (name)
840# define libnss_nisplus_hidden_data_weak(name) hidden_data_weak (name)
841# define libnss_nisplus_hidden_data_ver(local, name) hidden_data_ver (local, name)
842#else
843# define libnss_nisplus_hidden_proto(name, attrs...)
844# define libnss_nisplus_hidden_tls_proto(name, attrs...)
845# define libnss_nisplus_hidden_def(name)
846# define libnss_nisplus_hidden_weak(name)
847# define libnss_nisplus_hidden_ver(local, name)
848# define libnss_nisplus_hidden_data_def(name)
849# define libnss_nisplus_hidden_tls_def(name)
850# define libnss_nisplus_hidden_data_weak(name)
851# define libnss_nisplus_hidden_data_ver(local, name)
852#endif
853
854#define libc_hidden_builtin_proto(name, attrs...) libc_hidden_proto (name, ##attrs)
855#define libc_hidden_builtin_def(name) libc_hidden_def (name)
856#define libc_hidden_builtin_weak(name) libc_hidden_weak (name)
857#define libc_hidden_builtin_ver(local, name) libc_hidden_ver (local, name)
858#ifdef __ASSEMBLER__
859# define HIDDEN_BUILTIN_JUMPTARGET(name) HIDDEN_JUMPTARGET(name)
860#endif
861
862#if IS_IN (libutil)
863# define libutil_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
864# define libutil_hidden_tls_proto(name, attrs...) \
865 hidden_tls_proto (name, ##attrs)
866# define libutil_hidden_def(name) hidden_def (name)
867# define libutil_hidden_weak(name) hidden_weak (name)
868# define libutil_hidden_ver(local, name) hidden_ver (local, name)
869# define libutil_hidden_data_def(name) hidden_data_def (name)
870# define libutil_hidden_tls_def(name) hidden_tls_def (name)
871# define libutil_hidden_data_weak(name) hidden_data_weak (name)
872# define libutil_hidden_data_ver(local, name) hidden_data_ver (local, name)
873#else
874# define libutil_hidden_proto(name, attrs...)
875# define libutil_hidden_tls_proto(name, attrs...)
876# define libutil_hidden_def(name)
877# define libutil_hidden_weak(name)
878# define libutil_hidden_ver(local, name)
879# define libutil_hidden_data_def(name)
880# define libutil_hidden_tls_def(name)
881# define libutil_hidden_data_weak(name)
882# define libutil_hidden_data_ver(local, name)
883#endif
884
885/* Get some dirty hacks. */
886#include <symbol-hacks.h>
887
888/* Move compatibility symbols out of the way by placing them all in a
889 special section. */
890#ifndef __ASSEMBLER__
891# define attribute_compat_text_section \
892 __attribute__ ((section (".text.compat")))
893# define attribute_compat_data_section \
894 __attribute__ ((section (".data.compat")))
895#else
896# define compat_text_section .section ".text.compat", "ax";
897# define compat_data_section .section ".data.compat", "aw";
898#endif
899
900/* Helper / base macros for indirect function symbols. */
901#define __ifunc_resolver(type_name, name, expr, arg, init, classifier) \
902 classifier inhibit_stack_protector \
903 __typeof (type_name) *name##_ifunc (arg) \
904 { \
905 init (); \
906 __typeof (type_name) *res = expr; \
907 return res; \
908 }
909
910#ifdef HAVE_GCC_IFUNC
911# define __ifunc(type_name, name, expr, arg, init) \
912 extern __typeof (type_name) name __attribute__ \
913 ((ifunc (#name "_ifunc"))); \
914 __ifunc_resolver (type_name, name, expr, arg, init, static)
915
916# define __ifunc_hidden(type_name, name, expr, arg, init) \
917 __ifunc (type_name, name, expr, arg, init)
918#else
919/* Gcc does not support __attribute__ ((ifunc (...))). Use the old behaviour
920 as fallback. But keep in mind that the debug information for the ifunc
921 resolver functions is not correct. It contains the ifunc'ed function as
922 DW_AT_linkage_name. E.g. lldb uses this field and an inferior function
923 call of the ifunc'ed function will fail due to "no matching function for
924 call to ..." because the ifunc'ed function and the resolver function have
925 different signatures. (Gcc support is disabled at least on a ppc64le
926 Ubuntu 14.04 system.) */
927
928# define __ifunc(type_name, name, expr, arg, init) \
929 extern __typeof (type_name) name; \
930 __typeof (type_name) *name##_ifunc (arg) __asm__ (#name); \
931 __ifunc_resolver (type_name, name, expr, arg, init,) \
932 __asm__ (".type " #name ", %gnu_indirect_function");
933
934# define __ifunc_hidden(type_name, name, expr, arg, init) \
935 extern __typeof (type_name) __libc_##name; \
936 __ifunc (type_name, __libc_##name, expr, arg, init) \
937 strong_alias (__libc_##name, name);
938#endif /* !HAVE_GCC_IFUNC */
939
940/* The following macros are used for indirect function symbols in libc.so.
941 First of all, you need to have the function prototyped somewhere,
942 say in foo.h:
943
944 int foo (int __bar);
945
946 If you have an implementation for foo which e.g. uses a special hardware
947 feature which isn't available on all machines where this libc.so will be
948 used but decideable if available at runtime e.g. via hwcaps, you can provide
949 two or multiple implementations of foo:
950
951 int __foo_default (int __bar)
952 {
953 return __bar;
954 }
955
956 int __foo_special (int __bar)
957 {
958 return __bar;
959 }
960
961 If your function foo has no libc_hidden_proto (foo) defined for PLT
962 bypassing, you can use:
963
964 #define INIT_ARCH() unsigned long int hwcap = __GLRO(dl_hwcap);
965
966 libc_ifunc (foo, (hwcap & HWCAP_SPECIAL) ? __foo_special : __foo_default);
967
968 This will define a resolver function for foo which returns __foo_special or
969 __foo_default depending on your specified expression. Please note that you
970 have to define a macro function INIT_ARCH before using libc_ifunc macro as
971 it is called by the resolver function before evaluating the specified
972 expression. In this example it is used to prepare the hwcap variable.
973 The resolver function is assigned to an ifunc'ed symbol foo. Calls to foo
974 from inside or outside of libc.so will be indirected by a PLT call.
975
976 If your function foo has a libc_hidden_proto (foo) defined for PLT bypassing
977 and calls to foo within libc.so should always go to one specific
978 implementation of foo e.g. __foo_default then you have to add:
979
980 __hidden_ver1 (__foo_default, __GI_foo, __foo_default);
981
982 or a tweaked definition of libc_hidden_def macro after the __foo_default
983 function definition. Calls to foo within libc.so will always go directly to
984 __foo_default. Calls to foo from outside libc.so will be indirected by a
985 PLT call to ifunc'ed symbol foo which you have to define in a separate
986 compile unit:
987
988 #define foo __redirect_foo
989 #include <foo.h>
990 #undef foo
991
992 extern __typeof (__redirect_foo) __foo_default attribute_hidden;
993 extern __typeof (__redirect_foo) __foo_special attribute_hidden;
994
995 libc_ifunc_redirected (__redirect_foo, foo,
996 (hwcap & HWCAP_SPECIAL)
997 ? __foo_special
998 : __foo_default);
999
1000 This will define the ifunc'ed symbol foo like above. The redirection of foo
1001 in header file is needed to omit an additional defintion of __GI_foo which
1002 would end in a linker error while linking libc.so. You have to specify
1003 __redirect_foo as first parameter which is used within libc_ifunc_redirected
1004 macro in conjunction with typeof to define the ifunc'ed symbol foo.
1005
1006 If your function foo has a libc_hidden_proto (foo) defined and calls to foo
1007 within or from outside libc.so should go via ifunc'ed symbol, then you have
1008 to use:
1009
1010 libc_ifunc_hidden (foo, foo,
1011 (hwcap & HWCAP_SPECIAL)
1012 ? __foo_special
1013 : __foo_default);
1014 libc_hidden_def (foo)
1015
1016 The first parameter foo of libc_ifunc_hidden macro is used in the same way
1017 as for libc_ifunc_redirected macro. */
1018
1019#define libc_ifunc(name, expr) __ifunc (name, name, expr, void, INIT_ARCH)
1020
1021#define libc_ifunc_redirected(redirected_name, name, expr) \
1022 __ifunc (redirected_name, name, expr, void, INIT_ARCH)
1023
1024#define libc_ifunc_hidden(redirected_name, name, expr) \
1025 __ifunc_hidden (redirected_name, name, expr, void, INIT_ARCH)
1026
1027/* The body of the function is supposed to use __get_cpu_features
1028 which will, if necessary, initialize the data first. */
1029#define libm_ifunc_init()
1030#define libm_ifunc(name, expr) \
1031 __ifunc (name, name, expr, void, libm_ifunc_init)
1032
1033/* Add the compiler optimization to inhibit loop transformation to library
1034 calls. This is used to avoid recursive calls in memset and memmove
1035 default implementations. */
1036#ifdef HAVE_CC_INHIBIT_LOOP_TO_LIBCALL
1037# define inhibit_loop_to_libcall \
1038 __attribute__ ((__optimize__ ("-fno-tree-loop-distribute-patterns")))
1039#else
1040# define inhibit_loop_to_libcall
1041#endif
1042
1043/* These macros facilitate sharing source files with gnulib.
1044
1045 They are here instead of sys/cdefs.h because they should not be
1046 used in public header files.
1047
1048 Their definitions should be kept consistent with the definitions in
1049 gnulib-common.m4, but it is not necessary to cater to old non-GCC
1050 compilers, since they will only be used while building glibc itself.
1051 (Note that _GNUC_PREREQ cannot be used in this file.) */
1052
1053/* Define as a marker that can be attached to declarations that might not
1054 be used. This helps to reduce warnings, such as from
1055 GCC -Wunused-parameter. */
1056#if __GNUC__ >= 3 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 7)
1057# define _GL_UNUSED __attribute__ ((__unused__))
1058#else
1059# define _GL_UNUSED
1060#endif
1061
1062/* gcc supports the "unused" attribute on possibly unused labels, and
1063 g++ has since version 4.5. Note to support C++ as well as C,
1064 _GL_UNUSED_LABEL should be used with a trailing ; */
1065#if !defined __cplusplus || __GNUC__ > 4 \
1066 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 5)
1067# define _GL_UNUSED_LABEL _GL_UNUSED
1068#else
1069# define _GL_UNUSED_LABEL
1070#endif
1071
1072/* The __pure__ attribute was added in gcc 2.96. */
1073#if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 96)
1074# define _GL_ATTRIBUTE_PURE __attribute__ ((__pure__))
1075#else
1076# define _GL_ATTRIBUTE_PURE /* empty */
1077#endif
1078
1079/* The __const__ attribute was added in gcc 2.95. */
1080#if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 95)
1081# define _GL_ATTRIBUTE_CONST __attribute__ ((__const__))
1082#else
1083# define _GL_ATTRIBUTE_CONST /* empty */
1084#endif
1085
1086#endif /* !_ISOMAC */
1087#endif /* libc-symbols.h */
1088