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[/] [openrisc/] [trunk/] [gnu-stable/] [newlib-1.18.0/] [newlib/] [libc/] [sys/] [linux/] [linuxthreads/] [libc-symbols.h] - Blame information for rev 829

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Line No. Rev Author Line
1 207 jeremybenn
/* 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) 1995,1996,1997,1998,2000,2001 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, write to the Free
18
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
19
   02111-1307 USA.  */
20
 
21
#ifndef _LIBC_SYMBOLS_H
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#define _LIBC_SYMBOLS_H 1
23
 
24
/* This file's macros are included implicitly in the compilation of every
25
   file in the C library by -imacros.
26
 
27
   We include config.h which is generated by configure.
28
   It should define for us the following symbols:
29
 
30
   * HAVE_ASM_SET_DIRECTIVE if we have `.set B, A' instead of `A = B'.
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   * ASM_GLOBAL_DIRECTIVE with `.globl' or `.global'.
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   * HAVE_GNU_LD if using GNU ld, with support for weak symbols in a.out,
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   and for symbol set and warning messages extensions in a.out and ELF.
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   * HAVE_ELF if using ELF, which supports weak symbols using `.weak'.
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   * HAVE_ASM_WEAK_DIRECTIVE if we have weak symbols using `.weak'.
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   * HAVE_ASM_WEAKEXT_DIRECTIVE if we have weak symbols using `.weakext'.
37
 
38
   */
39
 
40
/* This is defined for the compilation of all C library code.  features.h
41
   tests this to avoid inclusion of stubs.h while compiling the library,
42
   before stubs.h has been generated.  Some library code that is shared
43
   with other packages also tests this symbol to see if it is being
44
   compiled as part of the C library.  We must define this before including
45
   config.h, because it makes some definitions conditional on whether libc
46
   itself is being compiled, or just some generator program.  */
47
#define _LIBC   1
48
 
49
/* Enable declarations of GNU extensions, since we are compiling them.  */
50
#define _GNU_SOURCE     1
51
/* And we also need the data for the reentrant functions.  */
52
#define _REENTRANT      1
53
 
54
#include <config.h>
55
 
56
/* The symbols in all the user (non-_) macros are C symbols.
57
   HAVE_GNU_LD without HAVE_ELF implies a.out.  */
58
 
59
#if defined HAVE_ASM_WEAK_DIRECTIVE || defined HAVE_ASM_WEAKEXT_DIRECTIVE
60
# define HAVE_WEAK_SYMBOLS
61
#endif
62
 
63
#ifndef __SYMBOL_PREFIX
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# ifdef NO_UNDERSCORES
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#  define __SYMBOL_PREFIX
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# else
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#  define __SYMBOL_PREFIX "_"
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# endif
69
#endif
70
 
71
#ifndef C_SYMBOL_NAME
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# ifdef NO_UNDERSCORES
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#  define C_SYMBOL_NAME(name) name
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# else
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#  define C_SYMBOL_NAME(name) _##name
76
# endif
77
#endif
78
 
79
#ifndef ASM_LINE_SEP
80
# define ASM_LINE_SEP ;
81
#endif
82
 
83
#ifndef C_SYMBOL_DOT_NAME
84
# define C_SYMBOL_DOT_NAME(name) .##name
85
#endif
86
 
87
#ifndef __ASSEMBLER__
88
/* GCC understands weak symbols and aliases; use its interface where
89
   possible, instead of embedded assembly language.  */
90
 
91
/* Define ALIASNAME as a strong alias for NAME.  */
92
# define strong_alias(name, aliasname) _strong_alias(name, aliasname)
93
# define _strong_alias(name, aliasname) \
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  extern __typeof (name) aliasname __attribute__ ((alias (#name)));
95
 
96
/* This comes between the return type and function name in
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   a function definition to make that definition weak.  */
98
# define weak_function __attribute__ ((weak))
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# define weak_const_function __attribute__ ((weak, __const__))
100
 
101
# ifdef HAVE_WEAK_SYMBOLS
102
 
103
/* Define ALIASNAME as a weak alias for NAME.
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   If weak aliases are not available, this defines a strong alias.  */
105
#  define weak_alias(name, aliasname) _weak_alias (name, aliasname)
106
#  define _weak_alias(name, aliasname) \
107
  extern __typeof (name) aliasname __attribute__ ((weak, alias (#name)));
108
 
109
/* Declare SYMBOL as weak undefined symbol (resolved to 0 if not defined).  */
110
#  define weak_extern(symbol) _weak_extern (symbol)
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#  ifdef HAVE_ASM_WEAKEXT_DIRECTIVE
112
#   define _weak_extern(symbol) asm (".weakext " __SYMBOL_PREFIX #symbol);
113
#  else
114
#   define _weak_extern(symbol)    asm (".weak " __SYMBOL_PREFIX #symbol);
115
#  endif
116
 
117
# else
118
 
119
#  define weak_alias(name, aliasname) strong_alias(name, aliasname)
120
#  define weak_extern(symbol) /* Nothing. */
121
 
122
# endif
123
 
124
#else /* __ASSEMBLER__ */
125
 
126
# ifdef HAVE_ASM_SET_DIRECTIVE
127
#  define strong_alias(original, alias)         \
128
  ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP       \
129
  .set C_SYMBOL_NAME (alias),C_SYMBOL_NAME (original)
130
# else
131
#  ifdef HAVE_ASM_GLOBAL_DOT_NAME
132
#   define strong_alias(original, alias)        \
133
  ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP       \
134
  C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original) ASM_LINE_SEP \
135
  ASM_GLOBAL_DIRECTIVE C_SYMBOL_DOT_NAME (alias) ASM_LINE_SEP   \
136
  C_SYMBOL_DOT_NAME (alias) = C_SYMBOL_DOT_NAME (original)
137
#  else
138
#   define strong_alias(original, alias)        \
139
  ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP       \
140
  C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original)
141
#  endif
142
# endif
143
 
144
# ifdef HAVE_WEAK_SYMBOLS
145
#  ifdef HAVE_ASM_WEAKEXT_DIRECTIVE
146
#   define weak_alias(original, alias)  \
147
  .weakext C_SYMBOL_NAME (alias), C_SYMBOL_NAME (original)
148
#   define weak_extern(symbol)  \
149
  .weakext C_SYMBOL_NAME (symbol)
150
 
151
#  else /* ! HAVE_ASM_WEAKEXT_DIRECTIVE */
152
 
153
#   ifdef HAVE_ASM_GLOBAL_DOT_NAME
154
#    define weak_alias(original, alias) \
155
  .weak C_SYMBOL_NAME (alias) ASM_LINE_SEP                      \
156
  C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original) ASM_LINE_SEP \
157
  ASM_GLOBAL_DIRECTIVE C_SYMBOL_DOT_NAME (alias) ASM_LINE_SEP   \
158
  C_SYMBOL_DOT_NAME (alias) = C_SYMBOL_DOT_NAME (original)
159
#   else
160
#    define weak_alias(original, alias) \
161
  .weak C_SYMBOL_NAME (alias) ASM_LINE_SEP      \
162
  C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original)
163
#   endif
164
 
165
#   define weak_extern(symbol)  \
166
  .weak C_SYMBOL_NAME (symbol)
167
 
168
#  endif /* ! HAVE_ASM_WEAKEXT_DIRECTIVE */
169
 
170
# else /* ! HAVE_WEAK_SYMBOLS */
171
 
172
#  define weak_alias(original, alias) strong_alias(original, alias)
173
#  define weak_extern(symbol) /* Nothing */
174
# endif /* ! HAVE_WEAK_SYMBOLS */
175
 
176
#endif /* __ASSEMBLER__ */
177
 
178
/* On some platforms we can make internal function calls (i.e., calls of
179
   functions not exported) a bit faster by using a different calling
180
   convention.  */
181
#ifndef internal_function
182
# define internal_function      /* empty */
183
#endif
184
 
185
/* Prepare for the case that `__builtin_expect' is not available.  */
186
#ifndef HAVE_BUILTIN_EXPECT
187
# define __builtin_expect(expr, val) (expr)
188
#endif
189
 
190
/* Determine the return address.  */
191
#define RETURN_ADDRESS(nr) \
192
  __builtin_extract_return_addr (__builtin_return_address (nr))
193
 
194
/* When a reference to SYMBOL is encountered, the linker will emit a
195
   warning message MSG.  */
196
#ifdef HAVE_GNU_LD
197
# ifdef HAVE_ELF
198
 
199
/* We want the .gnu.warning.SYMBOL section to be unallocated.  */
200
#  ifdef HAVE_ASM_PREVIOUS_DIRECTIVE
201
#   define __make_section_unallocated(section_string)   \
202
  asm (".section " section_string "\n\t.previous");
203
#  elif defined HAVE_ASM_POPSECTION_DIRECTIVE
204
#   define __make_section_unallocated(section_string)   \
205
  asm (".pushsection " section_string "\n\t.popsection");
206
#  else
207
#   define __make_section_unallocated(section_string)
208
#  endif
209
 
210
/* Tacking on "\n\t#" to the section name makes gcc put it's bogus
211
   section attributes on what looks like a comment to the assembler.  */
212
#  ifdef HAVE_SECTION_QUOTES
213
#   define link_warning(symbol, msg) \
214
  __make_section_unallocated (".gnu.warning." #symbol) \
215
  static const char __evoke_link_warning_##symbol[]     \
216
    __attribute__ ((section (".gnu.warning." #symbol "\"\n\t#\""))) = msg;
217
#  else
218
#   define link_warning(symbol, msg) \
219
  __make_section_unallocated (".gnu.warning." #symbol) \
220
  static const char __evoke_link_warning_##symbol[]     \
221
    __attribute__ ((section (".gnu.warning." #symbol "\n\t#"))) = msg;
222
#  endif
223
# else /* Not ELF: a.out */
224
#  ifdef HAVE_XCOFF
225
/* XCOFF does not support .stabs.
226
   The native aix linker will remove the .stab and .stabstr sections
227
   The gnu linker will have a fatal error if there is a relocation for
228
   symbol in the .stab section.  Silently disable this macro.  */
229
#   define link_warning(symbol, msg) 
230
#  else
231
#   define link_warning(symbol, msg)            \
232
     asm (".stabs \"" msg "\",30,0,0,0\n\t"     \
233
          ".stabs \"" __SYMBOL_PREFIX #symbol "\",1,0,0,0\n");
234
#  endif /* XCOFF */
235
# endif
236
#else
237
/* We will never be heard; they will all die horribly.  */
238
# define link_warning(symbol, msg)
239
#endif
240
 
241
/* A canned warning for sysdeps/stub functions.  */
242
#define stub_warning(name) \
243
  link_warning (name, \
244
                "warning: " #name " is not implemented and will always fail")
245
 
246
/*
247
 
248
*/
249
 
250
#ifdef HAVE_GNU_LD
251
 
252
/* Symbol set support macros.  */
253
 
254
# ifdef HAVE_ELF
255
 
256
/* Make SYMBOL, which is in the text segment, an element of SET.  */
257
#  define text_set_element(set, symbol) _elf_set_element(set, symbol)
258
/* Make SYMBOL, which is in the data segment, an element of SET.  */
259
#  define data_set_element(set, symbol) _elf_set_element(set, symbol)
260
/* Make SYMBOL, which is in the bss segment, an element of SET.  */
261
#  define bss_set_element(set, symbol)  _elf_set_element(set, symbol)
262
 
263
/* These are all done the same way in ELF.
264
   There is a new section created for each set.  */
265
#  ifdef SHARED
266
/* When building a shared library, make the set section writable,
267
   because it will need to be relocated at run time anyway.  */
268
#   define _elf_set_element(set, symbol) \
269
  static const void *__elf_set_##set##_element_##symbol##__ \
270
    __attribute__ ((unused, section (#set))) = &(symbol)
271
#  else
272
#   define _elf_set_element(set, symbol) \
273
  static const void *const __elf_set_##set##_element_##symbol##__ \
274
    __attribute__ ((unused, section (#set))) = &(symbol)
275
#  endif
276
 
277
/* Define SET as a symbol set.  This may be required (it is in a.out) to
278
   be able to use the set's contents.  */
279
#  define symbol_set_define(set)        symbol_set_declare(set)
280
 
281
/* Declare SET for use in this module, if defined in another module.  */
282
#  define symbol_set_declare(set) \
283
  extern void *const __start_##set __attribute__ ((__weak__));          \
284
  extern void *const __stop_##set __attribute__ ((__weak__));           \
285
  weak_extern (__start_##set) weak_extern (__stop_##set)
286
 
287
/* Return a pointer (void *const *) to the first element of SET.  */
288
#  define symbol_set_first_element(set) (&__start_##set)
289
 
290
/* Return true iff PTR (a void *const *) has been incremented
291
   past the last element in SET.  */
292
#  define symbol_set_end_p(set, ptr)    ((ptr) >= &__stop_##set)
293
 
294
# else  /* Not ELF: a.out.  */
295
 
296
#  ifdef HAVE_XCOFF
297
/* XCOFF does not support .stabs.
298
   The native aix linker will remove the .stab and .stabstr sections
299
   The gnu linker will have a fatal error if there is a relocation for
300
   symbol in the .stab section.  Silently disable these macros.  */
301
#   define text_set_element(set, symbol) 
302
#   define data_set_element(set, symbol) 
303
#   define bss_set_element(set, symbol)  
304
#  else
305
#   define text_set_element(set, symbol)        \
306
    asm (".stabs \"" __SYMBOL_PREFIX #set "\",23,0,0," __SYMBOL_PREFIX #symbol)
307
#   define data_set_element(set, symbol)        \
308
    asm (".stabs \"" __SYMBOL_PREFIX #set "\",25,0,0," __SYMBOL_PREFIX #symbol)
309
#   define bss_set_element(set, symbol) ?error Must use initialized data.
310
#  endif /* XCOFF */
311
#  define symbol_set_define(set)        void *const (set)[1];
312
#  define symbol_set_declare(set)       extern void *const (set)[1];
313
 
314
#  define symbol_set_first_element(set) &(set)[1]
315
#  define symbol_set_end_p(set, ptr)    (*(ptr) == 0)
316
 
317
# endif /* ELF.  */
318
#else
319
/* We cannot do anything in generial.  */
320
# define text_set_element(set, symbol) asm ("")
321
# define data_set_element(set, symbol) asm ("")
322
# define bss_set_element(set, symbol) asm ("")
323
# define symbol_set_define(set)         void *const (set)[1];
324
# define symbol_set_declare(set)        extern void *const (set)[1];
325
 
326
# define symbol_set_first_element(set)  &(set)[1]
327
# define symbol_set_end_p(set, ptr)     (*(ptr) == 0)
328
#endif  /* Have GNU ld.  */
329
 
330
#if DO_VERSIONING
331
# define symbol_version(real, name, version) \
332
     _symbol_version(real, name, version)
333
# define default_symbol_version(real, name, version) \
334
     _default_symbol_version(real, name, version)
335
# ifdef __ASSEMBLER__
336
#  define _symbol_version(real, name, version) \
337
     .symver real, name##@##version
338
#  define _default_symbol_version(real, name, version) \
339
     .symver real, name##@##@##version
340
# else
341
#  define _symbol_version(real, name, version) \
342
     __asm__ (".symver " #real "," #name "@" #version)
343
#  define _default_symbol_version(real, name, version) \
344
     __asm__ (".symver " #real "," #name "@@" #version)
345
# endif
346
#else
347
# define symbol_version(real, name, version)
348
# define default_symbol_version(real, name, version) \
349
  strong_alias(real, name)
350
#endif
351
 
352
#endif /* libc-symbols.h */

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