libgcc/crtstuff.c

   1 /* Specialized bits of code needed to support construction and
   2    destruction of file-scope objects in C++ code.
   3    Copyright (C) 1991-2016 Free Software Foundation, Inc.
   4    Contributed by Ron Guilmette (rfg@monkeys.com).
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 3, or (at your option) any later
  11 version.
  12
  13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 for more details.
  17
  18 Under Section 7 of GPL version 3, you are granted additional
  19 permissions described in the GCC Runtime Library Exception, version
  20 3.1, as published by the Free Software Foundation.
  21
  22 You should have received a copy of the GNU General Public License and
  23 a copy of the GCC Runtime Library Exception along with this program;
  24 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  25 <http://www.gnu.org/licenses/>.  */
  26
  27 /* This file is a bit like libgcc2.c in that it is compiled
  28    multiple times and yields multiple .o files.
  29
  30    This file is useful on target machines where the object file format
  31    supports multiple "user-defined" sections (e.g. COFF, ELF, ROSE).  On
  32    such systems, this file allows us to avoid running collect (or any
  33    other such slow and painful kludge).  Additionally, if the target
  34    system supports a .init section, this file allows us to support the
  35    linking of C++ code with a non-C++ main program.
  36
  37    Note that if INIT_SECTION_ASM_OP is defined in the tm.h file, then
  38    this file *will* make use of the .init section.  If that symbol is
  39    not defined however, then the .init section will not be used.
  40
  41    Currently, only ELF and COFF are supported.  It is likely however that
  42    ROSE could also be supported, if someone was willing to do the work to
  43    make whatever (small?) adaptations are needed.  (Some work may be
  44    needed on the ROSE assembler and linker also.)
  45
  46    This file must be compiled with gcc.  */
  47
  48 /* Target machine header files require this define. */
  49 #define IN_LIBGCC2
  50
  51 /* FIXME: Including auto-host is incorrect, but until we have
  52    identified the set of defines that need to go into auto-target.h,
  53    this will have to do.  */
  54 #include "auto-host.h"
  55 #undef caddr_t
  56 #undef pid_t
  57 #undef rlim_t
  58 #undef ssize_t
  59 #undef vfork
  60 #include "tconfig.h"
  61 #include "tsystem.h"
  62 #include "coretypes.h"
  63 #include "tm.h"
  64 #include "libgcc_tm.h"
  65 #include "unwind-dw2-fde.h"
  66
  67 #ifndef FORCE_CODE_SECTION_ALIGN
  68 # define FORCE_CODE_SECTION_ALIGN
  69 #endif
  70
  71 #ifndef CRT_CALL_STATIC_FUNCTION
  72 # define CRT_CALL_STATIC_FUNCTION(SECTION_OP, FUNC)     \
  73 static void __attribute__((__used__))                   \
  74 call_ ## FUNC (void)                                    \
  75 {                                                       \
  76   asm (SECTION_OP);                                     \
  77   FUNC ();                                              \
  78   FORCE_CODE_SECTION_ALIGN                              \
  79   asm (__LIBGCC_TEXT_SECTION_ASM_OP__);                         \
  80 }
  81 #endif
  82
  83 #if defined(TARGET_DL_ITERATE_PHDR) && \
  84    (defined(__DragonFly__) || defined(__FreeBSD__))
  85 #define BSD_DL_ITERATE_PHDR_AVAILABLE
  86 #endif
  87
  88 #if defined(OBJECT_FORMAT_ELF) \
  89     && !defined(OBJECT_FORMAT_FLAT) \
  90     && defined(HAVE_LD_EH_FRAME_HDR) \
  91     && !defined(inhibit_libc) && !defined(CRTSTUFFT_O) \
  92     && defined(BSD_DL_ITERATE_PHDR_AVAILABLE)
  93 #include <link.h>
  94 # define USE_PT_GNU_EH_FRAME
  95 #endif
  96
  97 #if defined(OBJECT_FORMAT_ELF) \
  98     && !defined(OBJECT_FORMAT_FLAT) \
  99     && defined(HAVE_LD_EH_FRAME_HDR) && defined(TARGET_DL_ITERATE_PHDR) \
 100     && !defined(inhibit_libc) && !defined(CRTSTUFFT_O) \
 101     && defined(__sun__) && defined(__svr4__)
 102 #include <link.h>
 103 # define USE_PT_GNU_EH_FRAME
 104 #endif
 105
 106 #if defined(OBJECT_FORMAT_ELF) \
 107     && !defined(OBJECT_FORMAT_FLAT) \
 108     && defined(HAVE_LD_EH_FRAME_HDR) \
 109     && !defined(inhibit_libc) && !defined(CRTSTUFFT_O) \
 110     && defined(__GLIBC__) && __GLIBC__ >= 2
 111 #include <link.h>
 112 /* uClibc pretends to be glibc 2.2 and DT_CONFIG is defined in its link.h.
 113    But it doesn't use PT_GNU_EH_FRAME ELF segment currently.  */
 114 # if !defined(__UCLIBC__) \
 115      && (__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 2) \
 116      || (__GLIBC__ == 2 && __GLIBC_MINOR__ == 2 && defined(DT_CONFIG)))
 117 #  define USE_PT_GNU_EH_FRAME
 118 # endif
 119 #endif
 120
 121 #if defined(OBJECT_FORMAT_ELF) \
 122     && !defined(OBJECT_FORMAT_FLAT) \
 123     && defined(HAVE_LD_EH_FRAME_HDR) \
 124     && !defined(CRTSTUFFT_O) \
 125     && defined(inhibit_libc) \
 126     && (defined(__GLIBC__) || defined(__gnu_linux__) || defined(__GNU__))
 127 /* On systems using glibc, an inhibit_libc build of libgcc is only
 128    part of a bootstrap process.  Build the same crt*.o as would be
 129    built with headers present, so that it is not necessary to build
 130    glibc more than once for the bootstrap to converge.  */
 131 # define USE_PT_GNU_EH_FRAME
 132 #endif
 133
 134 #ifdef USE_EH_FRAME_REGISTRY_ALWAYS
 135 # ifndef __LIBGCC_EH_FRAME_SECTION_NAME__
 136 #  error "Can't use explicit exception-frame-registration without __LIBGCC_EH_FRAME_SECTION_NAME__"
 137 # endif
 138 #endif
 139 #if defined(__LIBGCC_EH_FRAME_SECTION_NAME__) && (!defined(USE_PT_GNU_EH_FRAME) || defined(USE_EH_FRAME_REGISTRY_ALWAYS))
 140 # define USE_EH_FRAME_REGISTRY
 141 #endif
 142 #if defined(__LIBGCC_EH_FRAME_SECTION_NAME__) \
 143     && __LIBGCC_EH_TABLES_CAN_BE_READ_ONLY__
 144 # define EH_FRAME_SECTION_CONST const
 145 #else
 146 # define EH_FRAME_SECTION_CONST
 147 #endif
 148
 149 #if !defined(DTOR_LIST_END) && defined(OBJECT_FORMAT_ELF) \
 150     && defined(HAVE_GAS_HIDDEN) && !defined(FINI_ARRAY_SECTION_ASM_OP)
 151 # define HIDDEN_DTOR_LIST_END
 152 #endif
 153
 154 #if !defined(USE_TM_CLONE_REGISTRY) && defined(OBJECT_FORMAT_ELF)
 155 # define USE_TM_CLONE_REGISTRY 1
 156 #endif
 157
 158 /* We do not want to add the weak attribute to the declarations of these
 159    routines in unwind-dw2-fde.h because that will cause the definition of
 160    these symbols to be weak as well.
 161
 162    This exposes a core issue, how to handle creating weak references vs
 163    how to create weak definitions.  Either we have to have the definition
 164    of TARGET_WEAK_ATTRIBUTE be conditional in the shared header files or
 165    have a second declaration if we want a function's references to be weak,
 166    but not its definition.
 167
 168    Making TARGET_WEAK_ATTRIBUTE conditional seems like a good solution until
 169    one thinks about scaling to larger problems -- i.e., the condition under
 170    which TARGET_WEAK_ATTRIBUTE is active will eventually get far too
 171    complicated.
 172
 173    So, we take an approach similar to #pragma weak -- we have a second
 174    declaration for functions that we want to have weak references.
 175
 176    Neither way is particularly good.  */
 177
 178 /* References to __register_frame_info and __deregister_frame_info should
 179    be weak in this file if at all possible.  */
 180 extern void __register_frame_info (const void *, struct object *)
 181                                   TARGET_ATTRIBUTE_WEAK;
 182 extern void __register_frame_info_bases (const void *, struct object *,
 183                                          void *, void *)
 184                                   TARGET_ATTRIBUTE_WEAK;
 185 extern void *__deregister_frame_info (const void *)
 186                                      TARGET_ATTRIBUTE_WEAK;
 187 extern void *__deregister_frame_info_bases (const void *)
 188                                      TARGET_ATTRIBUTE_WEAK;
 189 extern void __do_global_ctors_1 (void);
 190
 191 /* Likewise for _Jv_RegisterClasses.  */
 192 extern void _Jv_RegisterClasses (void *) TARGET_ATTRIBUTE_WEAK;
 193
 194 /* Likewise for transactional memory clone tables.  */
 195 extern void _ITM_registerTMCloneTable (void *, size_t) TARGET_ATTRIBUTE_WEAK;
 196 extern void _ITM_deregisterTMCloneTable (void *) TARGET_ATTRIBUTE_WEAK;
 197
 198 #ifdef OBJECT_FORMAT_ELF
 199
 200 /*  Declare a pointer to void function type.  */
 201 typedef void (*func_ptr) (void);
 202 #define STATIC static
 203
 204 #else  /* OBJECT_FORMAT_ELF */
 205
 206 #include "gbl-ctors.h"
 207
 208 #define STATIC
 209
 210 #endif /* OBJECT_FORMAT_ELF */
 211
 212 #ifdef CRT_BEGIN
 213
 214 /* NOTE:  In order to be able to support SVR4 shared libraries, we arrange
 215    to have one set of symbols { __CTOR_LIST__, __DTOR_LIST__, __CTOR_END__,
 216    __DTOR_END__ } per root executable and also one set of these symbols
 217    per shared library.  So in any given whole process image, we may have
 218    multiple definitions of each of these symbols.  In order to prevent
 219    these definitions from conflicting with one another, and in order to
 220    ensure that the proper lists are used for the initialization/finalization
 221    of each individual shared library (respectively), we give these symbols
 222    only internal (i.e. `static') linkage, and we also make it a point to
 223    refer to only the __CTOR_END__ symbol in crtend.o and the __DTOR_LIST__
 224    symbol in crtbegin.o, where they are defined.  */
 225
 226 /* No need for .ctors/.dtors section if linker can place them in
 227    .init_array/.fini_array section.  */
 228 #ifndef USE_INITFINI_ARRAY
 229 /* The -1 is a flag to __do_global_[cd]tors indicating that this table
 230    does not start with a count of elements.  */
 231 #ifdef CTOR_LIST_BEGIN
 232 CTOR_LIST_BEGIN;
 233 #elif defined(__LIBGCC_CTORS_SECTION_ASM_OP__)
 234 /* Hack: force cc1 to switch to .data section early, so that assembling
 235    __CTOR_LIST__ does not undo our behind-the-back change to .ctors.  */
 236 static func_ptr force_to_data[1] __attribute__ ((__used__)) = { };
 237 asm (__LIBGCC_CTORS_SECTION_ASM_OP__);
 238 STATIC func_ptr __CTOR_LIST__[1]
 239   __attribute__ ((__used__, aligned(sizeof(func_ptr))))
 240   = { (func_ptr) (-1) };
 241 #else
 242 STATIC func_ptr __CTOR_LIST__[1]
 243   __attribute__ ((__used__, section(".ctors"), aligned(sizeof(func_ptr))))
 244   = { (func_ptr) (-1) };
 245 #endif /* __CTOR_LIST__ alternatives */
 246
 247 #ifdef DTOR_LIST_BEGIN
 248 DTOR_LIST_BEGIN;
 249 #elif defined(__LIBGCC_DTORS_SECTION_ASM_OP__)
 250 asm (__LIBGCC_DTORS_SECTION_ASM_OP__);
 251 STATIC func_ptr __DTOR_LIST__[1]
 252   __attribute__ ((aligned(sizeof(func_ptr))))
 253   = { (func_ptr) (-1) };
 254 #else
 255 STATIC func_ptr __DTOR_LIST__[1]
 256   __attribute__((section(".dtors"), aligned(sizeof(func_ptr))))
 257   = { (func_ptr) (-1) };
 258 #endif /* __DTOR_LIST__ alternatives */
 259 #endif /* USE_INITFINI_ARRAY */
 260
 261 #ifdef USE_EH_FRAME_REGISTRY
 262 /* Stick a label at the beginning of the frame unwind info so we can register
 263    and deregister it with the exception handling library code.  */
 264 STATIC EH_FRAME_SECTION_CONST char __EH_FRAME_BEGIN__[]
 265      __attribute__((section(__LIBGCC_EH_FRAME_SECTION_NAME__), aligned(4)))
 266      = { };
 267 #endif /* USE_EH_FRAME_REGISTRY */
 268
 269 #ifdef __LIBGCC_JCR_SECTION_NAME__
 270 /* Stick a label at the beginning of the java class registration info
 271    so we can register them properly.  */
 272 STATIC void *__JCR_LIST__[]
 273   __attribute__ ((used, section(__LIBGCC_JCR_SECTION_NAME__),
 274                   aligned(sizeof(void*))))
 275   = { };
 276 #endif /* __LIBGCC_JCR_SECTION_NAME__ */
 277
 278 #if USE_TM_CLONE_REGISTRY
 279 STATIC func_ptr __TMC_LIST__[]
 280   __attribute__((used, section(".tm_clone_table"), aligned(sizeof(void*))))
 281   = { };
 282 # ifdef HAVE_GAS_HIDDEN
 283 extern func_ptr __TMC_END__[] __attribute__((__visibility__ ("hidden")));
 284 # endif
 285
 286 static inline void
 287 deregister_tm_clones (void)
 288 {
 289   void (*fn) (void *);
 290
 291 #ifdef HAVE_GAS_HIDDEN
 292   if (__TMC_END__ - __TMC_LIST__ == 0)
 293     return;
 294 #else
 295   if (__TMC_LIST__[0] == NULL)
 296     return;
 297 #endif
 298
 299   fn = _ITM_deregisterTMCloneTable;
 300   __asm ("" : "+r" (fn));
 301   if (fn)
 302     fn (__TMC_LIST__);
 303 }
 304
 305 static inline void
 306 register_tm_clones (void)
 307 {
 308   void (*fn) (void *, size_t);
 309   size_t size;
 310
 311 #ifdef HAVE_GAS_HIDDEN
 312   size = (__TMC_END__ - __TMC_LIST__) / 2;
 313 #else
 314   for (size = 0; __TMC_LIST__[size * 2] != NULL; size++)
 315     continue;
 316 #endif
 317   if (size == 0)
 318     return;
 319
 320   fn = _ITM_registerTMCloneTable;
 321   __asm ("" : "+r" (fn));
 322   if (fn)
 323     fn (__TMC_LIST__, size);
 324 }
 325 #endif /* USE_TM_CLONE_REGISTRY */
 326
 327 #if defined(__LIBGCC_INIT_SECTION_ASM_OP__) \
 328     || defined(__LIBGCC_INIT_ARRAY_SECTION_ASM_OP__)
 329
 330 #ifdef OBJECT_FORMAT_ELF
 331
 332 /* Declare the __dso_handle variable.  It should have a unique value
 333    in every shared-object; in a main program its value is zero.  The
 334    object should in any case be protected.  This means the instance
 335    in one DSO or the main program is not used in another object.  The
 336    dynamic linker takes care of this.  */
 337
 338 #ifdef TARGET_LIBGCC_SDATA_SECTION
 339 extern void *__dso_handle __attribute__ ((__section__ (TARGET_LIBGCC_SDATA_SECTION)));
 340 #endif
 341 #ifdef HAVE_GAS_HIDDEN
 342 extern void *__dso_handle __attribute__ ((__visibility__ ("hidden")));
 343 #endif
 344 #ifdef CRTSTUFFS_O
 345 void *__dso_handle = &__dso_handle;
 346 #else
 347 void *__dso_handle = 0;
 348 #endif
 349
 350 /* The __cxa_finalize function may not be available so we use only a
 351    weak declaration.  */
 352 extern void __cxa_finalize (void *) TARGET_ATTRIBUTE_WEAK;
 353
 354 /* Run all the global destructors on exit from the program.  */
 355
 356 /* Some systems place the number of pointers in the first word of the
 357    table.  On SVR4 however, that word is -1.  In all cases, the table is
 358    null-terminated.  On SVR4, we start from the beginning of the list and
 359    invoke each per-compilation-unit destructor routine in order
 360    until we find that null.
 361
 362    Note that this function MUST be static.  There will be one of these
 363    functions in each root executable and one in each shared library, but
 364    although they all have the same code, each one is unique in that it
 365    refers to one particular associated `__DTOR_LIST__' which belongs to the
 366    same particular root executable or shared library file.
 367
 368    On some systems, this routine is run more than once from the .fini,
 369    when exit is called recursively, so we arrange to remember where in
 370    the list we left off processing, and we resume at that point,
 371    should we be re-invoked.  */
 372
 373 static void __attribute__((used))
 374 __do_global_dtors_aux (void)
 375 {
 376   static _Bool completed;
 377
 378   if (__builtin_expect (completed, 0))
 379     return;
 380
 381 #ifdef CRTSTUFFS_O
 382   if (__cxa_finalize)
 383     __cxa_finalize (__dso_handle);
 384 #endif
 385
 386 #ifdef FINI_ARRAY_SECTION_ASM_OP
 387   /* If we are using .fini_array then destructors will be run via that
 388      mechanism.  */
 389 #elif defined(HIDDEN_DTOR_LIST_END)
 390   {
 391     /* Safer version that makes sure only .dtors function pointers are
 392        called even if the static variable is maliciously changed.  */
 393     extern func_ptr __DTOR_END__[] __attribute__((visibility ("hidden")));
 394     static size_t dtor_idx;
 395     const size_t max_idx = __DTOR_END__ - __DTOR_LIST__ - 1;
 396     func_ptr *dtor_list;
 397
 398     __asm ("" : "=g" (dtor_list) : "0" (__DTOR_LIST__));
 399     while (dtor_idx < max_idx)
 400       dtor_list[++dtor_idx] ();
 401   }
 402 #else /* !defined (FINI_ARRAY_SECTION_ASM_OP) */
 403   {
 404     static func_ptr *p = __DTOR_LIST__ + 1;
 405     func_ptr f;
 406
 407     while ((f = *p))
 408       {
 409         p++;
 410         f ();
 411       }
 412   }
 413 #endif /* !defined(FINI_ARRAY_SECTION_ASM_OP) */
 414
 415 #if USE_TM_CLONE_REGISTRY
 416   deregister_tm_clones ();
 417 #endif /* USE_TM_CLONE_REGISTRY */
 418
 419 #ifdef USE_EH_FRAME_REGISTRY
 420 #ifdef CRT_GET_RFIB_DATA
 421   /* If we used the new __register_frame_info_bases interface,
 422      make sure that we deregister from the same place.  */
 423   if (__deregister_frame_info_bases)
 424     __deregister_frame_info_bases (__EH_FRAME_BEGIN__);
 425 #else
 426   if (__deregister_frame_info)
 427     __deregister_frame_info (__EH_FRAME_BEGIN__);
 428 #endif
 429 #endif
 430
 431   completed = 1;
 432 }
 433
 434 /* Stick a call to __do_global_dtors_aux into the .fini section.  */
 435 #ifdef FINI_SECTION_ASM_OP
 436 CRT_CALL_STATIC_FUNCTION (FINI_SECTION_ASM_OP, __do_global_dtors_aux)
 437 #elif defined (FINI_ARRAY_SECTION_ASM_OP)
 438 static func_ptr __do_global_dtors_aux_fini_array_entry[]
 439   __attribute__ ((__used__, section(".fini_array"), aligned(sizeof(func_ptr))))
 440   = { __do_global_dtors_aux };
 441 #else /* !FINI_SECTION_ASM_OP && !FINI_ARRAY_SECTION_ASM_OP */
 442 static void __attribute__((used))
 443 __do_global_dtors_aux_1 (void)
 444 {
 445   atexit (__do_global_dtors_aux);
 446 }
 447 CRT_CALL_STATIC_FUNCTION (__LIBGCC_INIT_SECTION_ASM_OP__,
 448                           __do_global_dtors_aux_1)
 449 #endif
 450
 451 #if defined(USE_EH_FRAME_REGISTRY) \
 452     || defined(__LIBGCC_JCR_SECTION_NAME__) \
 453     || defined(USE_TM_CLONE_REGISTRY)
 454 /* Stick a call to __register_frame_info into the .init section.  For some
 455    reason calls with no arguments work more reliably in .init, so stick the
 456    call in another function.  */
 457
 458 static void __attribute__((used))
 459 frame_dummy (void)
 460 {
 461 #ifdef USE_EH_FRAME_REGISTRY
 462   static struct object object;
 463 #ifdef CRT_GET_RFIB_DATA
 464   void *tbase, *dbase;
 465   tbase = 0;
 466   CRT_GET_RFIB_DATA (dbase);
 467   if (__register_frame_info_bases)
 468     __register_frame_info_bases (__EH_FRAME_BEGIN__, &object, tbase, dbase);
 469 #else
 470   if (__register_frame_info)
 471     __register_frame_info (__EH_FRAME_BEGIN__, &object);
 472 #endif /* CRT_GET_RFIB_DATA */
 473 #endif /* USE_EH_FRAME_REGISTRY */
 474
 475 #ifdef __LIBGCC_JCR_SECTION_NAME__
 476   void **jcr_list;
 477   __asm ("" : "=g" (jcr_list) : "0" (__JCR_LIST__));
 478   if (__builtin_expect (*jcr_list != NULL, 0))
 479     {
 480       void (*register_classes) (void *) = _Jv_RegisterClasses;
 481       __asm ("" : "+r" (register_classes));
 482       if (register_classes)
 483         register_classes (jcr_list);
 484     }
 485 #endif /* __LIBGCC_JCR_SECTION_NAME__ */
 486
 487 #if USE_TM_CLONE_REGISTRY
 488   register_tm_clones ();
 489 #endif /* USE_TM_CLONE_REGISTRY */
 490 }
 491
 492 #ifdef __LIBGCC_INIT_SECTION_ASM_OP__
 493 CRT_CALL_STATIC_FUNCTION (__LIBGCC_INIT_SECTION_ASM_OP__, frame_dummy)
 494 #else /* defined(__LIBGCC_INIT_SECTION_ASM_OP__) */
 495 static func_ptr __frame_dummy_init_array_entry[]
 496   __attribute__ ((__used__, section(".init_array"), aligned(sizeof(func_ptr))))
 497   = { frame_dummy };
 498 #endif /* !defined(__LIBGCC_INIT_SECTION_ASM_OP__) */
 499 #endif /* USE_EH_FRAME_REGISTRY || __LIBGCC_JCR_SECTION_NAME__ || USE_TM_CLONE_REGISTRY */
 500
 501 #else  /* OBJECT_FORMAT_ELF */
 502
 503 /* The function __do_global_ctors_aux is compiled twice (once in crtbegin.o
 504    and once in crtend.o).  It must be declared static to avoid a link
 505    error.  Here, we define __do_global_ctors as an externally callable
 506    function.  It is externally callable so that __main can invoke it when
 507    INVOKE__main is defined.  This has the additional effect of forcing cc1
 508    to switch to the .text section.  */
 509
 510 static void __do_global_ctors_aux (void);
 511 void
 512 __do_global_ctors (void)
 513 {
 514 #ifdef INVOKE__main
 515   /* If __main won't actually call __do_global_ctors then it doesn't matter
 516      what's inside the function.  The inside of __do_global_ctors_aux is
 517      called automatically in that case.  And the Alliant fx2800 linker
 518      crashes on this reference.  So prevent the crash.  */
 519   __do_global_ctors_aux ();
 520 #endif
 521 }
 522
 523 asm (__LIBGCC_INIT_SECTION_ASM_OP__);   /* cc1 doesn't know that we are switching! */
 524
 525 /* A routine to invoke all of the global constructors upon entry to the
 526    program.  We put this into the .init section (for systems that have
 527    such a thing) so that we can properly perform the construction of
 528    file-scope static-storage C++ objects within shared libraries.  */
 529
 530 static void __attribute__((used))
 531 __do_global_ctors_aux (void)    /* prologue goes in .init section */
 532 {
 533   FORCE_CODE_SECTION_ALIGN      /* explicit align before switch to .text */
 534   asm (__LIBGCC_TEXT_SECTION_ASM_OP__); /* don't put epilogue and body in .init */
 535   DO_GLOBAL_CTORS_BODY;
 536   atexit (__do_global_dtors);
 537 }
 538
 539 #endif /* OBJECT_FORMAT_ELF */
 540
 541 #elif defined(HAS_INIT_SECTION) /* ! __LIBGCC_INIT_SECTION_ASM_OP__ */
 542
 543 extern void __do_global_dtors (void);
 544
 545 /* This case is used by the Irix 6 port, which supports named sections but
 546    not an SVR4-style .fini section.  __do_global_dtors can be non-static
 547    in this case because we protect it with -hidden_symbol.  */
 548
 549 void
 550 __do_global_dtors (void)
 551 {
 552   func_ptr *p, f;
 553   for (p = __DTOR_LIST__ + 1; (f = *p); p++)
 554     f ();
 555
 556 #if USE_TM_CLONE_REGISTRY
 557   deregister_tm_clones ();
 558 #endif /* USE_TM_CLONE_REGISTRY */
 559
 560 #ifdef USE_EH_FRAME_REGISTRY
 561   if (__deregister_frame_info)
 562     __deregister_frame_info (__EH_FRAME_BEGIN__);
 563 #endif
 564 }
 565
 566 #if defined(USE_EH_FRAME_REGISTRY) \
 567     || defined(__LIBGCC_JCR_SECTION_NAME__) \
 568     || defined(USE_TM_CLONE_REGISTRY)
 569 /* A helper function for __do_global_ctors, which is in crtend.o.  Here
 570    in crtbegin.o, we can reference a couple of symbols not visible there.
 571    Plus, since we're before libgcc.a, we have no problems referencing
 572    functions from there.  */
 573 void
 574 __do_global_ctors_1(void)
 575 {
 576 #ifdef USE_EH_FRAME_REGISTRY
 577   static struct object object;
 578   if (__register_frame_info)
 579     __register_frame_info (__EH_FRAME_BEGIN__, &object);
 580 #endif
 581
 582 #ifdef __LIBGCC_JCR_SECTION_NAME__
 583   void **jcr_list;
 584   __asm ("" : "=g" (jcr_list) : "0" (__JCR_LIST__));
 585   if (__builtin_expect (*jcr_list != NULL, 0))
 586     {
 587       void (*register_classes) (void *) = _Jv_RegisterClasses;
 588       __asm ("" : "+r" (register_classes));
 589       if (register_classes)
 590         register_classes (jcr_list);
 591     }
 592 #endif
 593
 594 #if USE_TM_CLONE_REGISTRY
 595   register_tm_clones ();
 596 #endif /* USE_TM_CLONE_REGISTRY */
 597 }
 598 #endif /* USE_EH_FRAME_REGISTRY || __LIBGCC_JCR_SECTION_NAME__ || USE_TM_CLONE_REGISTRY */
 599
 600 #else /* ! __LIBGCC_INIT_SECTION_ASM_OP__ && ! HAS_INIT_SECTION */
 601 #error "What are you doing with crtstuff.c, then?"
 602 #endif
 603
 604 #elif defined(CRT_END) /* ! CRT_BEGIN */
 605
 606 /* No need for .ctors/.dtors section if linker can place them in
 607    .init_array/.fini_array section.  */
 608 #ifndef USE_INITFINI_ARRAY
 609 /* Put a word containing zero at the end of each of our two lists of function
 610    addresses.  Note that the words defined here go into the .ctors and .dtors
 611    sections of the crtend.o file, and since that file is always linked in
 612    last, these words naturally end up at the very ends of the two lists
 613    contained in these two sections.  */
 614
 615 #ifdef CTOR_LIST_END
 616 CTOR_LIST_END;
 617 #elif defined(__LIBGCC_CTORS_SECTION_ASM_OP__)
 618 /* Hack: force cc1 to switch to .data section early, so that assembling
 619    __CTOR_LIST__ does not undo our behind-the-back change to .ctors.  */
 620 static func_ptr force_to_data[1] __attribute__ ((__used__)) = { };
 621 asm (__LIBGCC_CTORS_SECTION_ASM_OP__);
 622 STATIC func_ptr __CTOR_END__[1]
 623   __attribute__((aligned(sizeof(func_ptr))))
 624   = { (func_ptr) 0 };
 625 #else
 626 STATIC func_ptr __CTOR_END__[1]
 627   __attribute__((section(".ctors"), aligned(sizeof(func_ptr))))
 628   = { (func_ptr) 0 };
 629 #endif
 630
 631 #ifdef DTOR_LIST_END
 632 DTOR_LIST_END;
 633 #elif defined(HIDDEN_DTOR_LIST_END)
 634 #ifdef __LIBGCC_DTORS_SECTION_ASM_OP__
 635 asm (__LIBGCC_DTORS_SECTION_ASM_OP__);
 636 #endif
 637 func_ptr __DTOR_END__[1]
 638   __attribute__ ((used,
 639 #ifndef __LIBGCC_DTORS_SECTION_ASM_OP__
 640                   section(".dtors"),
 641 #endif
 642                   aligned(sizeof(func_ptr)), visibility ("hidden")))
 643   = { (func_ptr) 0 };
 644 #elif defined(__LIBGCC_DTORS_SECTION_ASM_OP__)
 645 asm (__LIBGCC_DTORS_SECTION_ASM_OP__);
 646 STATIC func_ptr __DTOR_END__[1]
 647   __attribute__ ((used, aligned(sizeof(func_ptr))))
 648   = { (func_ptr) 0 };
 649 #else
 650 STATIC func_ptr __DTOR_END__[1]
 651   __attribute__((used, section(".dtors"), aligned(sizeof(func_ptr))))
 652   = { (func_ptr) 0 };
 653 #endif
 654 #endif /* USE_INITFINI_ARRAY */
 655
 656 #ifdef __LIBGCC_EH_FRAME_SECTION_NAME__
 657 /* Terminate the frame unwind info section with a 4byte 0 as a sentinel;
 658    this would be the 'length' field in a real FDE.  */
 659 # if __INT_MAX__ == 2147483647
 660 typedef int int32;
 661 # elif __LONG_MAX__ == 2147483647
 662 typedef long int32;
 663 # elif __SHRT_MAX__ == 2147483647
 664 typedef short int32;
 665 # else
 666 #  error "Missing a 4 byte integer"
 667 # endif
 668 STATIC EH_FRAME_SECTION_CONST int32 __FRAME_END__[]
 669      __attribute__ ((used, section(__LIBGCC_EH_FRAME_SECTION_NAME__),
 670                      aligned(sizeof(int32))))
 671      = { 0 };
 672 #endif /* __LIBGCC_EH_FRAME_SECTION_NAME__ */
 673
 674 #ifdef __LIBGCC_JCR_SECTION_NAME__
 675 /* Null terminate the .jcr section array.  */
 676 STATIC void *__JCR_END__[1]
 677    __attribute__ ((used, section(__LIBGCC_JCR_SECTION_NAME__),
 678                    aligned(sizeof(void *))))
 679    = { 0 };
 680 #endif /* __LIBGCC_JCR_SECTION_NAME__ */
 681
 682 #if USE_TM_CLONE_REGISTRY
 683 # ifndef HAVE_GAS_HIDDEN
 684 static
 685 # endif
 686 func_ptr __TMC_END__[]
 687   __attribute__((used, section(".tm_clone_table"), aligned(sizeof(void *))))
 688 # ifdef HAVE_GAS_HIDDEN
 689   __attribute__((__visibility__ ("hidden"))) = { };
 690 # else
 691   = { 0, 0 };
 692 # endif
 693 #endif /* USE_TM_CLONE_REGISTRY */
 694
 695 #ifdef __LIBGCC_INIT_ARRAY_SECTION_ASM_OP__
 696
 697 /* If we are using .init_array, there is nothing to do.  */
 698
 699 #elif defined(__LIBGCC_INIT_SECTION_ASM_OP__)
 700
 701 #ifdef OBJECT_FORMAT_ELF
 702 static void __attribute__((used))
 703 __do_global_ctors_aux (void)
 704 {
 705   func_ptr *p;
 706   for (p = __CTOR_END__ - 1; *p != (func_ptr) -1; p--)
 707     (*p) ();
 708 }
 709
 710 /* Stick a call to __do_global_ctors_aux into the .init section.  */
 711 CRT_CALL_STATIC_FUNCTION (__LIBGCC_INIT_SECTION_ASM_OP__, __do_global_ctors_aux)
 712 #else  /* OBJECT_FORMAT_ELF */
 713
 714 /* Stick the real initialization code, followed by a normal sort of
 715    function epilogue at the very end of the .init section for this
 716    entire root executable file or for this entire shared library file.
 717
 718    Note that we use some tricks here to get *just* the body and just
 719    a function epilogue (but no function prologue) into the .init
 720    section of the crtend.o file.  Specifically, we switch to the .text
 721    section, start to define a function, and then we switch to the .init
 722    section just before the body code.
 723
 724    Earlier on, we put the corresponding function prologue into the .init
 725    section of the crtbegin.o file (which will be linked in first).
 726
 727    Note that we want to invoke all constructors for C++ file-scope static-
 728    storage objects AFTER any other possible initialization actions which
 729    may be performed by the code in the .init section contributions made by
 730    other libraries, etc.  That's because those other initializations may
 731    include setup operations for very primitive things (e.g. initializing
 732    the state of the floating-point coprocessor, etc.) which should be done
 733    before we start to execute any of the user's code.  */
 734
 735 static void
 736 __do_global_ctors_aux (void)    /* prologue goes in .text section */
 737 {
 738   asm (__LIBGCC_INIT_SECTION_ASM_OP__);
 739   DO_GLOBAL_CTORS_BODY;
 740   atexit (__do_global_dtors);
 741 }                               /* epilogue and body go in .init section */
 742
 743 FORCE_CODE_SECTION_ALIGN
 744 asm (__LIBGCC_TEXT_SECTION_ASM_OP__);
 745
 746 #endif /* OBJECT_FORMAT_ELF */
 747
 748 #elif defined(HAS_INIT_SECTION) /* ! __LIBGCC_INIT_SECTION_ASM_OP__ */
 749
 750 extern void __do_global_ctors (void);
 751
 752 /* This case is used by the Irix 6 port, which supports named sections but
 753    not an SVR4-style .init section.  __do_global_ctors can be non-static
 754    in this case because we protect it with -hidden_symbol.  */
 755 void
 756 __do_global_ctors (void)
 757 {
 758   func_ptr *p;
 759 #if defined(USE_EH_FRAME_REGISTRY) \
 760     || defined(__LIBGCC_JCR_SECTION_NAME__) \
 761     || defined(USE_TM_CLONE_REGISTRY)
 762   __do_global_ctors_1();
 763 #endif
 764   for (p = __CTOR_END__ - 1; *p != (func_ptr) -1; p--)
 765     (*p) ();
 766 }
 767
 768 #else /* ! __LIBGCC_INIT_SECTION_ASM_OP__ && ! HAS_INIT_SECTION */
 769 #error "What are you doing with crtstuff.c, then?"
 770 #endif
 771
 772 #else /* ! CRT_BEGIN && ! CRT_END */
 773 #error "One of CRT_BEGIN or CRT_END must be defined."
 774 #endif