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 #if USE_TM_CLONE_REGISTRY
 270 STATIC func_ptr __TMC_LIST__[]
 271   __attribute__((used, section(".tm_clone_table"), aligned(sizeof(void*))))
 272   = { };
 273 # ifdef HAVE_GAS_HIDDEN
 274 extern func_ptr __TMC_END__[] __attribute__((__visibility__ ("hidden")));
 275 # endif
 276
 277 static inline void
 278 deregister_tm_clones (void)
 279 {
 280   void (*fn) (void *);
 281
 282 #ifdef HAVE_GAS_HIDDEN
 283   func_ptr *end = __TMC_END__;
 284   // Do not optimize the comparison to false.
 285   __asm ("" : "+g" (end));
 286   if (__TMC_LIST__ == end)
 287     return;
 288 #else
 289   if (__TMC_LIST__[0] == NULL)
 290     return;
 291 #endif
 292
 293   fn = _ITM_deregisterTMCloneTable;
 294   __asm ("" : "+r" (fn));
 295   if (fn)
 296     fn (__TMC_LIST__);
 297 }
 298
 299 static inline void
 300 register_tm_clones (void)
 301 {
 302   void (*fn) (void *, size_t);
 303   size_t size;
 304
 305 #ifdef HAVE_GAS_HIDDEN
 306   func_ptr *end = __TMC_END__;
 307   // Do not optimize the comparison to false.
 308   __asm ("" : "+g" (end));
 309   size = (end - __TMC_LIST__) / 2;
 310 #else
 311   for (size = 0; __TMC_LIST__[size * 2] != NULL; size++)
 312     continue;
 313 #endif
 314   if (size == 0)
 315     return;
 316
 317   fn = _ITM_registerTMCloneTable;
 318   __asm ("" : "+r" (fn));
 319   if (fn)
 320     fn (__TMC_LIST__, size);
 321 }
 322 #endif /* USE_TM_CLONE_REGISTRY */
 323
 324 #if defined(__LIBGCC_INIT_SECTION_ASM_OP__) \
 325     || defined(__LIBGCC_INIT_ARRAY_SECTION_ASM_OP__)
 326
 327 #ifdef OBJECT_FORMAT_ELF
 328
 329 /* Declare the __dso_handle variable.  It should have a unique value
 330    in every shared-object; in a main program its value is zero.  The
 331    object should in any case be protected.  This means the instance
 332    in one DSO or the main program is not used in another object.  The
 333    dynamic linker takes care of this.  */
 334
 335 #ifdef TARGET_LIBGCC_SDATA_SECTION
 336 extern void *__dso_handle __attribute__ ((__section__ (TARGET_LIBGCC_SDATA_SECTION)));
 337 #endif
 338 #ifdef HAVE_GAS_HIDDEN
 339 extern void *__dso_handle __attribute__ ((__visibility__ ("hidden")));
 340 #endif
 341 #ifdef CRTSTUFFS_O
 342 void *__dso_handle = &__dso_handle;
 343 #else
 344 void *__dso_handle = 0;
 345 #endif
 346
 347 /* The __cxa_finalize function may not be available so we use only a
 348    weak declaration.  */
 349 extern void __cxa_finalize (void *) TARGET_ATTRIBUTE_WEAK;
 350
 351 /* Run all the global destructors on exit from the program.  */
 352
 353 /* Some systems place the number of pointers in the first word of the
 354    table.  On SVR4 however, that word is -1.  In all cases, the table is
 355    null-terminated.  On SVR4, we start from the beginning of the list and
 356    invoke each per-compilation-unit destructor routine in order
 357    until we find that null.
 358
 359    Note that this function MUST be static.  There will be one of these
 360    functions in each root executable and one in each shared library, but
 361    although they all have the same code, each one is unique in that it
 362    refers to one particular associated `__DTOR_LIST__' which belongs to the
 363    same particular root executable or shared library file.
 364
 365    On some systems, this routine is run more than once from the .fini,
 366    when exit is called recursively, so we arrange to remember where in
 367    the list we left off processing, and we resume at that point,
 368    should we be re-invoked.  */
 369
 370 static void __attribute__((used))
 371 __do_global_dtors_aux (void)
 372 {
 373   static _Bool completed;
 374
 375   if (__builtin_expect (completed, 0))
 376     return;
 377
 378 #ifdef CRTSTUFFS_O
 379   if (__cxa_finalize)
 380     __cxa_finalize (__dso_handle);
 381 #endif
 382
 383 #ifdef FINI_ARRAY_SECTION_ASM_OP
 384   /* If we are using .fini_array then destructors will be run via that
 385      mechanism.  */
 386 #elif defined(HIDDEN_DTOR_LIST_END)
 387   {
 388     /* Safer version that makes sure only .dtors function pointers are
 389        called even if the static variable is maliciously changed.  */
 390     extern func_ptr __DTOR_END__[] __attribute__((visibility ("hidden")));
 391     static size_t dtor_idx;
 392     const size_t max_idx = __DTOR_END__ - __DTOR_LIST__ - 1;
 393     func_ptr *dtor_list;
 394
 395     __asm ("" : "=g" (dtor_list) : "0" (__DTOR_LIST__));
 396     while (dtor_idx < max_idx)
 397       dtor_list[++dtor_idx] ();
 398   }
 399 #else /* !defined (FINI_ARRAY_SECTION_ASM_OP) */
 400   {
 401     static func_ptr *p = __DTOR_LIST__ + 1;
 402     func_ptr f;
 403
 404     while ((f = *p))
 405       {
 406         p++;
 407         f ();
 408       }
 409   }
 410 #endif /* !defined(FINI_ARRAY_SECTION_ASM_OP) */
 411
 412 #if USE_TM_CLONE_REGISTRY
 413   deregister_tm_clones ();
 414 #endif /* USE_TM_CLONE_REGISTRY */
 415
 416 #ifdef USE_EH_FRAME_REGISTRY
 417 #ifdef CRT_GET_RFIB_DATA
 418   /* If we used the new __register_frame_info_bases interface,
 419      make sure that we deregister from the same place.  */
 420   if (__deregister_frame_info_bases)
 421     __deregister_frame_info_bases (__EH_FRAME_BEGIN__);
 422 #else
 423   if (__deregister_frame_info)
 424     __deregister_frame_info (__EH_FRAME_BEGIN__);
 425 #endif
 426 #endif
 427
 428   completed = 1;
 429 }
 430
 431 /* Stick a call to __do_global_dtors_aux into the .fini section.  */
 432 #ifdef FINI_SECTION_ASM_OP
 433 CRT_CALL_STATIC_FUNCTION (FINI_SECTION_ASM_OP, __do_global_dtors_aux)
 434 #elif defined (FINI_ARRAY_SECTION_ASM_OP)
 435 static func_ptr __do_global_dtors_aux_fini_array_entry[]
 436   __attribute__ ((__used__, section(".fini_array"), aligned(sizeof(func_ptr))))
 437   = { __do_global_dtors_aux };
 438 #else /* !FINI_SECTION_ASM_OP && !FINI_ARRAY_SECTION_ASM_OP */
 439 static void __attribute__((used))
 440 __do_global_dtors_aux_1 (void)
 441 {
 442   atexit (__do_global_dtors_aux);
 443 }
 444 CRT_CALL_STATIC_FUNCTION (__LIBGCC_INIT_SECTION_ASM_OP__,
 445                           __do_global_dtors_aux_1)
 446 #endif
 447
 448 #if defined(USE_EH_FRAME_REGISTRY) \
 449     || defined(USE_TM_CLONE_REGISTRY)
 450 /* Stick a call to __register_frame_info into the .init section.  For some
 451    reason calls with no arguments work more reliably in .init, so stick the
 452    call in another function.  */
 453
 454 static void __attribute__((used))
 455 frame_dummy (void)
 456 {
 457 #ifdef USE_EH_FRAME_REGISTRY
 458   static struct object object;
 459 #ifdef CRT_GET_RFIB_DATA
 460   void *tbase, *dbase;
 461   tbase = 0;
 462   CRT_GET_RFIB_DATA (dbase);
 463   if (__register_frame_info_bases)
 464     __register_frame_info_bases (__EH_FRAME_BEGIN__, &object, tbase, dbase);
 465 #else
 466   if (__register_frame_info)
 467     __register_frame_info (__EH_FRAME_BEGIN__, &object);
 468 #endif /* CRT_GET_RFIB_DATA */
 469 #endif /* USE_EH_FRAME_REGISTRY */
 470
 471 #if USE_TM_CLONE_REGISTRY
 472   register_tm_clones ();
 473 #endif /* USE_TM_CLONE_REGISTRY */
 474 }
 475
 476 #ifdef __LIBGCC_INIT_SECTION_ASM_OP__
 477 CRT_CALL_STATIC_FUNCTION (__LIBGCC_INIT_SECTION_ASM_OP__, frame_dummy)
 478 #else /* defined(__LIBGCC_INIT_SECTION_ASM_OP__) */
 479 static func_ptr __frame_dummy_init_array_entry[]
 480   __attribute__ ((__used__, section(".init_array"), aligned(sizeof(func_ptr))))
 481   = { frame_dummy };
 482 #endif /* !defined(__LIBGCC_INIT_SECTION_ASM_OP__) */
 483 #endif /* USE_EH_FRAME_REGISTRY || USE_TM_CLONE_REGISTRY */
 484
 485 #else  /* OBJECT_FORMAT_ELF */
 486
 487 /* The function __do_global_ctors_aux is compiled twice (once in crtbegin.o
 488    and once in crtend.o).  It must be declared static to avoid a link
 489    error.  Here, we define __do_global_ctors as an externally callable
 490    function.  It is externally callable so that __main can invoke it when
 491    INVOKE__main is defined.  This has the additional effect of forcing cc1
 492    to switch to the .text section.  */
 493
 494 static void __do_global_ctors_aux (void);
 495 void
 496 __do_global_ctors (void)
 497 {
 498 #ifdef INVOKE__main
 499   /* If __main won't actually call __do_global_ctors then it doesn't matter
 500      what's inside the function.  The inside of __do_global_ctors_aux is
 501      called automatically in that case.  And the Alliant fx2800 linker
 502      crashes on this reference.  So prevent the crash.  */
 503   __do_global_ctors_aux ();
 504 #endif
 505 }
 506
 507 asm (__LIBGCC_INIT_SECTION_ASM_OP__);   /* cc1 doesn't know that we are switching! */
 508
 509 /* A routine to invoke all of the global constructors upon entry to the
 510    program.  We put this into the .init section (for systems that have
 511    such a thing) so that we can properly perform the construction of
 512    file-scope static-storage C++ objects within shared libraries.  */
 513
 514 static void __attribute__((used))
 515 __do_global_ctors_aux (void)    /* prologue goes in .init section */
 516 {
 517   FORCE_CODE_SECTION_ALIGN      /* explicit align before switch to .text */
 518   asm (__LIBGCC_TEXT_SECTION_ASM_OP__); /* don't put epilogue and body in .init */
 519   DO_GLOBAL_CTORS_BODY;
 520   atexit (__do_global_dtors);
 521 }
 522
 523 #endif /* OBJECT_FORMAT_ELF */
 524
 525 #elif defined(HAS_INIT_SECTION) /* ! __LIBGCC_INIT_SECTION_ASM_OP__ */
 526
 527 extern void __do_global_dtors (void);
 528
 529 /* This case is used by the Irix 6 port, which supports named sections but
 530    not an SVR4-style .fini section.  __do_global_dtors can be non-static
 531    in this case because we protect it with -hidden_symbol.  */
 532
 533 void
 534 __do_global_dtors (void)
 535 {
 536   func_ptr *p, f;
 537   for (p = __DTOR_LIST__ + 1; (f = *p); p++)
 538     f ();
 539
 540 #if USE_TM_CLONE_REGISTRY
 541   deregister_tm_clones ();
 542 #endif /* USE_TM_CLONE_REGISTRY */
 543
 544 #ifdef USE_EH_FRAME_REGISTRY
 545   if (__deregister_frame_info)
 546     __deregister_frame_info (__EH_FRAME_BEGIN__);
 547 #endif
 548 }
 549
 550 #if defined(USE_EH_FRAME_REGISTRY) \
 551     || defined(USE_TM_CLONE_REGISTRY)
 552 /* A helper function for __do_global_ctors, which is in crtend.o.  Here
 553    in crtbegin.o, we can reference a couple of symbols not visible there.
 554    Plus, since we're before libgcc.a, we have no problems referencing
 555    functions from there.  */
 556 void
 557 __do_global_ctors_1(void)
 558 {
 559 #ifdef USE_EH_FRAME_REGISTRY
 560   static struct object object;
 561   if (__register_frame_info)
 562     __register_frame_info (__EH_FRAME_BEGIN__, &object);
 563 #endif
 564
 565 #if USE_TM_CLONE_REGISTRY
 566   register_tm_clones ();
 567 #endif /* USE_TM_CLONE_REGISTRY */
 568 }
 569 #endif /* USE_EH_FRAME_REGISTRY || USE_TM_CLONE_REGISTRY */
 570
 571 #else /* ! __LIBGCC_INIT_SECTION_ASM_OP__ && ! HAS_INIT_SECTION */
 572 #error "What are you doing with crtstuff.c, then?"
 573 #endif
 574
 575 #elif defined(CRT_END) /* ! CRT_BEGIN */
 576
 577 /* No need for .ctors/.dtors section if linker can place them in
 578    .init_array/.fini_array section.  */
 579 #ifndef USE_INITFINI_ARRAY
 580 /* Put a word containing zero at the end of each of our two lists of function
 581    addresses.  Note that the words defined here go into the .ctors and .dtors
 582    sections of the crtend.o file, and since that file is always linked in
 583    last, these words naturally end up at the very ends of the two lists
 584    contained in these two sections.  */
 585
 586 #ifdef CTOR_LIST_END
 587 CTOR_LIST_END;
 588 #elif defined(__LIBGCC_CTORS_SECTION_ASM_OP__)
 589 /* Hack: force cc1 to switch to .data section early, so that assembling
 590    __CTOR_LIST__ does not undo our behind-the-back change to .ctors.  */
 591 static func_ptr force_to_data[1] __attribute__ ((__used__)) = { };
 592 asm (__LIBGCC_CTORS_SECTION_ASM_OP__);
 593 STATIC func_ptr __CTOR_END__[1]
 594   __attribute__((aligned(sizeof(func_ptr))))
 595   = { (func_ptr) 0 };
 596 #else
 597 STATIC func_ptr __CTOR_END__[1]
 598   __attribute__((section(".ctors"), aligned(sizeof(func_ptr))))
 599   = { (func_ptr) 0 };
 600 #endif
 601
 602 #ifdef DTOR_LIST_END
 603 DTOR_LIST_END;
 604 #elif defined(HIDDEN_DTOR_LIST_END)
 605 #ifdef __LIBGCC_DTORS_SECTION_ASM_OP__
 606 asm (__LIBGCC_DTORS_SECTION_ASM_OP__);
 607 #endif
 608 func_ptr __DTOR_END__[1]
 609   __attribute__ ((used,
 610 #ifndef __LIBGCC_DTORS_SECTION_ASM_OP__
 611                   section(".dtors"),
 612 #endif
 613                   aligned(sizeof(func_ptr)), visibility ("hidden")))
 614   = { (func_ptr) 0 };
 615 #elif defined(__LIBGCC_DTORS_SECTION_ASM_OP__)
 616 asm (__LIBGCC_DTORS_SECTION_ASM_OP__);
 617 STATIC func_ptr __DTOR_END__[1]
 618   __attribute__ ((used, aligned(sizeof(func_ptr))))
 619   = { (func_ptr) 0 };
 620 #else
 621 STATIC func_ptr __DTOR_END__[1]
 622   __attribute__((used, section(".dtors"), aligned(sizeof(func_ptr))))
 623   = { (func_ptr) 0 };
 624 #endif
 625 #endif /* USE_INITFINI_ARRAY */
 626
 627 #ifdef __LIBGCC_EH_FRAME_SECTION_NAME__
 628 /* Terminate the frame unwind info section with a 4byte 0 as a sentinel;
 629    this would be the 'length' field in a real FDE.  */
 630 # if __INT_MAX__ == 2147483647
 631 typedef int int32;
 632 # elif __LONG_MAX__ == 2147483647
 633 typedef long int32;
 634 # elif __SHRT_MAX__ == 2147483647
 635 typedef short int32;
 636 # else
 637 #  error "Missing a 4 byte integer"
 638 # endif
 639 STATIC EH_FRAME_SECTION_CONST int32 __FRAME_END__[]
 640      __attribute__ ((used, section(__LIBGCC_EH_FRAME_SECTION_NAME__),
 641                      aligned(sizeof(int32))))
 642      = { 0 };
 643 #endif /* __LIBGCC_EH_FRAME_SECTION_NAME__ */
 644
 645 #if USE_TM_CLONE_REGISTRY
 646 # ifndef HAVE_GAS_HIDDEN
 647 static
 648 # endif
 649 func_ptr __TMC_END__[]
 650   __attribute__((used, section(".tm_clone_table"), aligned(sizeof(void *))))
 651 # ifdef HAVE_GAS_HIDDEN
 652   __attribute__((__visibility__ ("hidden"))) = { };
 653 # else
 654   = { 0, 0 };
 655 # endif
 656 #endif /* USE_TM_CLONE_REGISTRY */
 657
 658 #ifdef __LIBGCC_INIT_ARRAY_SECTION_ASM_OP__
 659
 660 /* If we are using .init_array, there is nothing to do.  */
 661
 662 #elif defined(__LIBGCC_INIT_SECTION_ASM_OP__)
 663
 664 #ifdef OBJECT_FORMAT_ELF
 665 static void __attribute__((used))
 666 __do_global_ctors_aux (void)
 667 {
 668   func_ptr *p;
 669   for (p = __CTOR_END__ - 1; *p != (func_ptr) -1; p--)
 670     (*p) ();
 671 }
 672
 673 /* Stick a call to __do_global_ctors_aux into the .init section.  */
 674 CRT_CALL_STATIC_FUNCTION (__LIBGCC_INIT_SECTION_ASM_OP__, __do_global_ctors_aux)
 675 #else  /* OBJECT_FORMAT_ELF */
 676
 677 /* Stick the real initialization code, followed by a normal sort of
 678    function epilogue at the very end of the .init section for this
 679    entire root executable file or for this entire shared library file.
 680
 681    Note that we use some tricks here to get *just* the body and just
 682    a function epilogue (but no function prologue) into the .init
 683    section of the crtend.o file.  Specifically, we switch to the .text
 684    section, start to define a function, and then we switch to the .init
 685    section just before the body code.
 686
 687    Earlier on, we put the corresponding function prologue into the .init
 688    section of the crtbegin.o file (which will be linked in first).
 689
 690    Note that we want to invoke all constructors for C++ file-scope static-
 691    storage objects AFTER any other possible initialization actions which
 692    may be performed by the code in the .init section contributions made by
 693    other libraries, etc.  That's because those other initializations may
 694    include setup operations for very primitive things (e.g. initializing
 695    the state of the floating-point coprocessor, etc.) which should be done
 696    before we start to execute any of the user's code.  */
 697
 698 static void
 699 __do_global_ctors_aux (void)    /* prologue goes in .text section */
 700 {
 701   asm (__LIBGCC_INIT_SECTION_ASM_OP__);
 702   DO_GLOBAL_CTORS_BODY;
 703   atexit (__do_global_dtors);
 704 }                               /* epilogue and body go in .init section */
 705
 706 FORCE_CODE_SECTION_ALIGN
 707 asm (__LIBGCC_TEXT_SECTION_ASM_OP__);
 708
 709 #endif /* OBJECT_FORMAT_ELF */
 710
 711 #elif defined(HAS_INIT_SECTION) /* ! __LIBGCC_INIT_SECTION_ASM_OP__ */
 712
 713 extern void __do_global_ctors (void);
 714
 715 /* This case is used by the Irix 6 port, which supports named sections but
 716    not an SVR4-style .init section.  __do_global_ctors can be non-static
 717    in this case because we protect it with -hidden_symbol.  */
 718 void
 719 __do_global_ctors (void)
 720 {
 721   func_ptr *p;
 722 #if defined(USE_EH_FRAME_REGISTRY) \
 723     || defined(USE_TM_CLONE_REGISTRY)
 724   __do_global_ctors_1();
 725 #endif
 726   for (p = __CTOR_END__ - 1; *p != (func_ptr) -1; p--)
 727     (*p) ();
 728 }
 729
 730 #else /* ! __LIBGCC_INIT_SECTION_ASM_OP__ && ! HAS_INIT_SECTION */
 731 #error "What are you doing with crtstuff.c, then?"
 732 #endif
 733
 734 #else /* ! CRT_BEGIN && ! CRT_END */
 735 #error "One of CRT_BEGIN or CRT_END must be defined."
 736 #endif