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, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001
   4    2002, 2003, 2004, 2005, 2006, 2007, 2009, 2010, 2011
   5    Free Software Foundation, Inc.
   6    Contributed by Ron Guilmette (rfg@monkeys.com).
   7
   8 This file is part of GCC.
   9
  10 GCC is free software; you can redistribute it and/or modify it under
  11 the terms of the GNU General Public License as published by the Free
  12 Software Foundation; either version 3, or (at your option) any later
  13 version.
  14
  15 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  16 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  17 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  18 for more details.
  19
  20 Under Section 7 of GPL version 3, you are granted additional
  21 permissions described in the GCC Runtime Library Exception, version
  22 3.1, as published by the Free Software Foundation.
  23
  24 You should have received a copy of the GNU General Public License and
  25 a copy of the GCC Runtime Library Exception along with this program;
  26 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  27 <http://www.gnu.org/licenses/>.  */
  28
  29 /* This file is a bit like libgcc2.c in that it is compiled
  30    multiple times and yields multiple .o files.
  31
  32    This file is useful on target machines where the object file format
  33    supports multiple "user-defined" sections (e.g. COFF, ELF, ROSE).  On
  34    such systems, this file allows us to avoid running collect (or any
  35    other such slow and painful kludge).  Additionally, if the target
  36    system supports a .init section, this file allows us to support the
  37    linking of C++ code with a non-C++ main program.
  38
  39    Note that if INIT_SECTION_ASM_OP is defined in the tm.h file, then
  40    this file *will* make use of the .init section.  If that symbol is
  41    not defined however, then the .init section will not be used.
  42
  43    Currently, only ELF and COFF are supported.  It is likely however that
  44    ROSE could also be supported, if someone was willing to do the work to
  45    make whatever (small?) adaptations are needed.  (Some work may be
  46    needed on the ROSE assembler and linker also.)
  47
  48    This file must be compiled with gcc.  */
  49
  50 /* Target machine header files require this define. */
  51 #define IN_LIBGCC2
  52
  53 /* FIXME: Including auto-host is incorrect, but until we have
  54    identified the set of defines that need to go into auto-target.h,
  55    this will have to do.  */
  56 #include "auto-host.h"
  57 #undef pid_t
  58 #undef rlim_t
  59 #undef ssize_t
  60 #undef vfork
  61 #include "tconfig.h"
  62 #include "tsystem.h"
  63 #include "coretypes.h"
  64 #include "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 (TEXT_SECTION_ASM_OP);                            \
  80 }
  81 #endif
  82
  83 #if defined(OBJECT_FORMAT_ELF) \
  84     && !defined(OBJECT_FORMAT_FLAT) \
  85     && defined(HAVE_LD_EH_FRAME_HDR) \
  86     && !defined(inhibit_libc) && !defined(CRTSTUFFT_O) \
  87     && defined(__FreeBSD__) && __FreeBSD__ >= 7
  88 #include <link.h>
  89 # define USE_PT_GNU_EH_FRAME
  90 #endif
  91
  92 #if defined(OBJECT_FORMAT_ELF) \
  93     && !defined(OBJECT_FORMAT_FLAT) \
  94     && defined(HAVE_LD_EH_FRAME_HDR) && defined(TARGET_DL_ITERATE_PHDR) \
  95     && !defined(inhibit_libc) && !defined(CRTSTUFFT_O) \
  96     && defined(__sun__) && defined(__svr4__)
  97 #include <link.h>
  98 # define USE_PT_GNU_EH_FRAME
  99 #endif
 100
 101 #if defined(OBJECT_FORMAT_ELF) \
 102     && !defined(OBJECT_FORMAT_FLAT) \
 103     && defined(HAVE_LD_EH_FRAME_HDR) \
 104     && !defined(inhibit_libc) && !defined(CRTSTUFFT_O) \
 105     && defined(__GLIBC__) && __GLIBC__ >= 2
 106 #include <link.h>
 107 /* uClibc pretends to be glibc 2.2 and DT_CONFIG is defined in its link.h.
 108    But it doesn't use PT_GNU_EH_FRAME ELF segment currently.  */
 109 # if !defined(__UCLIBC__) \
 110      && (__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 2) \
 111      || (__GLIBC__ == 2 && __GLIBC_MINOR__ == 2 && defined(DT_CONFIG)))
 112 #  define USE_PT_GNU_EH_FRAME
 113 # endif
 114 #endif
 115 #if defined(EH_FRAME_SECTION_NAME) && !defined(USE_PT_GNU_EH_FRAME)
 116 # define USE_EH_FRAME_REGISTRY
 117 #endif
 118 #if defined(EH_FRAME_SECTION_NAME) && EH_TABLES_CAN_BE_READ_ONLY
 119 # define EH_FRAME_SECTION_CONST const
 120 #else
 121 # define EH_FRAME_SECTION_CONST
 122 #endif
 123
 124 #if !defined(DTOR_LIST_END) && defined(OBJECT_FORMAT_ELF) \
 125     && defined(HAVE_GAS_HIDDEN) && !defined(FINI_ARRAY_SECTION_ASM_OP)
 126 # define HIDDEN_DTOR_LIST_END
 127 #endif
 128
 129 /* We do not want to add the weak attribute to the declarations of these
 130    routines in unwind-dw2-fde.h because that will cause the definition of
 131    these symbols to be weak as well.
 132
 133    This exposes a core issue, how to handle creating weak references vs
 134    how to create weak definitions.  Either we have to have the definition
 135    of TARGET_WEAK_ATTRIBUTE be conditional in the shared header files or
 136    have a second declaration if we want a function's references to be weak,
 137    but not its definition.
 138
 139    Making TARGET_WEAK_ATTRIBUTE conditional seems like a good solution until
 140    one thinks about scaling to larger problems -- i.e., the condition under
 141    which TARGET_WEAK_ATTRIBUTE is active will eventually get far too
 142    complicated.
 143
 144    So, we take an approach similar to #pragma weak -- we have a second
 145    declaration for functions that we want to have weak references.
 146
 147    Neither way is particularly good.  */
 148
 149 /* References to __register_frame_info and __deregister_frame_info should
 150    be weak in this file if at all possible.  */
 151 extern void __register_frame_info (const void *, struct object *)
 152                                   TARGET_ATTRIBUTE_WEAK;
 153 extern void __register_frame_info_bases (const void *, struct object *,
 154                                          void *, void *)
 155                                   TARGET_ATTRIBUTE_WEAK;
 156 extern void *__deregister_frame_info (const void *)
 157                                      TARGET_ATTRIBUTE_WEAK;
 158 extern void *__deregister_frame_info_bases (const void *)
 159                                      TARGET_ATTRIBUTE_WEAK;
 160 extern void __do_global_ctors_1 (void);
 161
 162 /* Likewise for _Jv_RegisterClasses.  */
 163 extern void _Jv_RegisterClasses (void *) TARGET_ATTRIBUTE_WEAK;
 164
 165 #ifdef OBJECT_FORMAT_ELF
 166
 167 /*  Declare a pointer to void function type.  */
 168 typedef void (*func_ptr) (void);
 169 #define STATIC static
 170
 171 #else  /* OBJECT_FORMAT_ELF */
 172
 173 #include "gbl-ctors.h"
 174
 175 #define STATIC
 176
 177 #endif /* OBJECT_FORMAT_ELF */
 178
 179 #ifdef CRT_BEGIN
 180
 181 /* NOTE:  In order to be able to support SVR4 shared libraries, we arrange
 182    to have one set of symbols { __CTOR_LIST__, __DTOR_LIST__, __CTOR_END__,
 183    __DTOR_END__ } per root executable and also one set of these symbols
 184    per shared library.  So in any given whole process image, we may have
 185    multiple definitions of each of these symbols.  In order to prevent
 186    these definitions from conflicting with one another, and in order to
 187    ensure that the proper lists are used for the initialization/finalization
 188    of each individual shared library (respectively), we give these symbols
 189    only internal (i.e. `static') linkage, and we also make it a point to
 190    refer to only the __CTOR_END__ symbol in crtend.o and the __DTOR_LIST__
 191    symbol in crtbegin.o, where they are defined.  */
 192
 193 /* No need for .ctors/.dtors section if linker can place them in
 194    .init_array/.fini_array section.  */
 195 #ifndef USE_INITFINI_ARRAY
 196 /* The -1 is a flag to __do_global_[cd]tors indicating that this table
 197    does not start with a count of elements.  */
 198 #ifdef CTOR_LIST_BEGIN
 199 CTOR_LIST_BEGIN;
 200 #elif defined(CTORS_SECTION_ASM_OP)
 201 /* Hack: force cc1 to switch to .data section early, so that assembling
 202    __CTOR_LIST__ does not undo our behind-the-back change to .ctors.  */
 203 static func_ptr force_to_data[1] __attribute__ ((__used__)) = { };
 204 asm (CTORS_SECTION_ASM_OP);
 205 STATIC func_ptr __CTOR_LIST__[1]
 206   __attribute__ ((__used__, aligned(sizeof(func_ptr))))
 207   = { (func_ptr) (-1) };
 208 #else
 209 STATIC func_ptr __CTOR_LIST__[1]
 210   __attribute__ ((__used__, section(".ctors"), aligned(sizeof(func_ptr))))
 211   = { (func_ptr) (-1) };
 212 #endif /* __CTOR_LIST__ alternatives */
 213
 214 #ifdef DTOR_LIST_BEGIN
 215 DTOR_LIST_BEGIN;
 216 #elif defined(DTORS_SECTION_ASM_OP)
 217 asm (DTORS_SECTION_ASM_OP);
 218 STATIC func_ptr __DTOR_LIST__[1]
 219   __attribute__ ((aligned(sizeof(func_ptr))))
 220   = { (func_ptr) (-1) };
 221 #else
 222 STATIC func_ptr __DTOR_LIST__[1]
 223   __attribute__((section(".dtors"), aligned(sizeof(func_ptr))))
 224   = { (func_ptr) (-1) };
 225 #endif /* __DTOR_LIST__ alternatives */
 226 #endif /* USE_INITFINI_ARRAY */
 227
 228 #ifdef USE_EH_FRAME_REGISTRY
 229 /* Stick a label at the beginning of the frame unwind info so we can register
 230    and deregister it with the exception handling library code.  */
 231 STATIC EH_FRAME_SECTION_CONST char __EH_FRAME_BEGIN__[]
 232      __attribute__((section(EH_FRAME_SECTION_NAME), aligned(4)))
 233      = { };
 234 #endif /* USE_EH_FRAME_REGISTRY */
 235
 236 #ifdef JCR_SECTION_NAME
 237 /* Stick a label at the beginning of the java class registration info
 238    so we can register them properly.  */
 239 STATIC void *__JCR_LIST__[]
 240   __attribute__ ((used, section(JCR_SECTION_NAME), aligned(sizeof(void*))))
 241   = { };
 242 #endif /* JCR_SECTION_NAME */
 243
 244 #if defined(INIT_SECTION_ASM_OP) || defined(INIT_ARRAY_SECTION_ASM_OP)
 245
 246 #ifdef OBJECT_FORMAT_ELF
 247
 248 /* Declare the __dso_handle variable.  It should have a unique value
 249    in every shared-object; in a main program its value is zero.  The
 250    object should in any case be protected.  This means the instance
 251    in one DSO or the main program is not used in another object.  The
 252    dynamic linker takes care of this.  */
 253
 254 #ifdef TARGET_LIBGCC_SDATA_SECTION
 255 extern void *__dso_handle __attribute__ ((__section__ (TARGET_LIBGCC_SDATA_SECTION)));
 256 #endif
 257 #ifdef HAVE_GAS_HIDDEN
 258 extern void *__dso_handle __attribute__ ((__visibility__ ("hidden")));
 259 #endif
 260 #ifdef CRTSTUFFS_O
 261 void *__dso_handle = &__dso_handle;
 262 #else
 263 void *__dso_handle = 0;
 264 #endif
 265
 266 /* The __cxa_finalize function may not be available so we use only a
 267    weak declaration.  */
 268 extern void __cxa_finalize (void *) TARGET_ATTRIBUTE_WEAK;
 269
 270 /* Run all the global destructors on exit from the program.  */
 271
 272 /* Some systems place the number of pointers in the first word of the
 273    table.  On SVR4 however, that word is -1.  In all cases, the table is
 274    null-terminated.  On SVR4, we start from the beginning of the list and
 275    invoke each per-compilation-unit destructor routine in order
 276    until we find that null.
 277
 278    Note that this function MUST be static.  There will be one of these
 279    functions in each root executable and one in each shared library, but
 280    although they all have the same code, each one is unique in that it
 281    refers to one particular associated `__DTOR_LIST__' which belongs to the
 282    same particular root executable or shared library file.
 283
 284    On some systems, this routine is run more than once from the .fini,
 285    when exit is called recursively, so we arrange to remember where in
 286    the list we left off processing, and we resume at that point,
 287    should we be re-invoked.  */
 288
 289 static void __attribute__((used))
 290 __do_global_dtors_aux (void)
 291 {
 292   static _Bool completed;
 293
 294   if (__builtin_expect (completed, 0))
 295     return;
 296
 297 #ifdef CRTSTUFFS_O
 298   if (__cxa_finalize)
 299     __cxa_finalize (__dso_handle);
 300 #endif
 301
 302 #ifdef FINI_ARRAY_SECTION_ASM_OP
 303   /* If we are using .fini_array then destructors will be run via that
 304      mechanism.  */
 305 #elif defined(HIDDEN_DTOR_LIST_END)
 306   {
 307     /* Safer version that makes sure only .dtors function pointers are
 308        called even if the static variable is maliciously changed.  */
 309     extern func_ptr __DTOR_END__[] __attribute__((visibility ("hidden")));
 310     static size_t dtor_idx;
 311     const size_t max_idx = __DTOR_END__ - __DTOR_LIST__ - 1;
 312     func_ptr f;
 313
 314     while (dtor_idx < max_idx)
 315       {
 316         f = __DTOR_LIST__[++dtor_idx];
 317         f ();
 318       }
 319   }
 320 #else /* !defined (FINI_ARRAY_SECTION_ASM_OP) */
 321   {
 322     static func_ptr *p = __DTOR_LIST__ + 1;
 323     func_ptr f;
 324
 325     while ((f = *p))
 326       {
 327         p++;
 328         f ();
 329       }
 330   }
 331 #endif /* !defined(FINI_ARRAY_SECTION_ASM_OP) */
 332
 333 #ifdef USE_EH_FRAME_REGISTRY
 334 #ifdef CRT_GET_RFIB_DATA
 335   /* If we used the new __register_frame_info_bases interface,
 336      make sure that we deregister from the same place.  */
 337   if (__deregister_frame_info_bases)
 338     __deregister_frame_info_bases (__EH_FRAME_BEGIN__);
 339 #else
 340   if (__deregister_frame_info)
 341     __deregister_frame_info (__EH_FRAME_BEGIN__);
 342 #endif
 343 #endif
 344
 345   completed = 1;
 346 }
 347
 348 /* Stick a call to __do_global_dtors_aux into the .fini section.  */
 349 #ifdef FINI_SECTION_ASM_OP
 350 CRT_CALL_STATIC_FUNCTION (FINI_SECTION_ASM_OP, __do_global_dtors_aux)
 351 #elif defined (FINI_ARRAY_SECTION_ASM_OP)
 352 static func_ptr __do_global_dtors_aux_fini_array_entry[]
 353   __attribute__ ((__used__, section(".fini_array")))
 354   = { __do_global_dtors_aux };
 355 #else /* !FINI_SECTION_ASM_OP && !FINI_ARRAY_SECTION_ASM_OP */
 356 static void __attribute__((used))
 357 __do_global_dtors_aux_1 (void)
 358 {
 359   atexit (__do_global_dtors_aux);
 360 }
 361 CRT_CALL_STATIC_FUNCTION (INIT_SECTION_ASM_OP, __do_global_dtors_aux_1)
 362 #endif
 363
 364 #if defined(USE_EH_FRAME_REGISTRY) || defined(JCR_SECTION_NAME)
 365 /* Stick a call to __register_frame_info into the .init section.  For some
 366    reason calls with no arguments work more reliably in .init, so stick the
 367    call in another function.  */
 368
 369 static void __attribute__((used))
 370 frame_dummy (void)
 371 {
 372 #ifdef USE_EH_FRAME_REGISTRY
 373   static struct object object;
 374 #ifdef CRT_GET_RFIB_DATA
 375   void *tbase, *dbase;
 376   tbase = 0;
 377   CRT_GET_RFIB_DATA (dbase);
 378   if (__register_frame_info_bases)
 379     __register_frame_info_bases (__EH_FRAME_BEGIN__, &object, tbase, dbase);
 380 #else
 381   if (__register_frame_info)
 382     __register_frame_info (__EH_FRAME_BEGIN__, &object);
 383 #endif /* CRT_GET_RFIB_DATA */
 384 #endif /* USE_EH_FRAME_REGISTRY */
 385 #ifdef JCR_SECTION_NAME
 386   if (__JCR_LIST__[0])
 387     {
 388       void (*register_classes) (void *) = _Jv_RegisterClasses;
 389       __asm ("" : "+r" (register_classes));
 390       if (register_classes)
 391         register_classes (__JCR_LIST__);
 392     }
 393 #endif /* JCR_SECTION_NAME */
 394 }
 395
 396 #ifdef INIT_SECTION_ASM_OP
 397 CRT_CALL_STATIC_FUNCTION (INIT_SECTION_ASM_OP, frame_dummy)
 398 #else /* defined(INIT_SECTION_ASM_OP) */
 399 static func_ptr __frame_dummy_init_array_entry[]
 400   __attribute__ ((__used__, section(".init_array")))
 401   = { frame_dummy };
 402 #endif /* !defined(INIT_SECTION_ASM_OP) */
 403 #endif /* USE_EH_FRAME_REGISTRY || JCR_SECTION_NAME */
 404
 405 #else  /* OBJECT_FORMAT_ELF */
 406
 407 /* The function __do_global_ctors_aux is compiled twice (once in crtbegin.o
 408    and once in crtend.o).  It must be declared static to avoid a link
 409    error.  Here, we define __do_global_ctors as an externally callable
 410    function.  It is externally callable so that __main can invoke it when
 411    INVOKE__main is defined.  This has the additional effect of forcing cc1
 412    to switch to the .text section.  */
 413
 414 static void __do_global_ctors_aux (void);
 415 void
 416 __do_global_ctors (void)
 417 {
 418 #ifdef INVOKE__main
 419   /* If __main won't actually call __do_global_ctors then it doesn't matter
 420      what's inside the function.  The inside of __do_global_ctors_aux is
 421      called automatically in that case.  And the Alliant fx2800 linker
 422      crashes on this reference.  So prevent the crash.  */
 423   __do_global_ctors_aux ();
 424 #endif
 425 }
 426
 427 asm (INIT_SECTION_ASM_OP);      /* cc1 doesn't know that we are switching! */
 428
 429 /* A routine to invoke all of the global constructors upon entry to the
 430    program.  We put this into the .init section (for systems that have
 431    such a thing) so that we can properly perform the construction of
 432    file-scope static-storage C++ objects within shared libraries.  */
 433
 434 static void __attribute__((used))
 435 __do_global_ctors_aux (void)    /* prologue goes in .init section */
 436 {
 437   FORCE_CODE_SECTION_ALIGN      /* explicit align before switch to .text */
 438   asm (TEXT_SECTION_ASM_OP);    /* don't put epilogue and body in .init */
 439   DO_GLOBAL_CTORS_BODY;
 440   atexit (__do_global_dtors);
 441 }
 442
 443 #endif /* OBJECT_FORMAT_ELF */
 444
 445 #elif defined(HAS_INIT_SECTION) /* ! INIT_SECTION_ASM_OP */
 446
 447 extern void __do_global_dtors (void);
 448
 449 /* This case is used by the Irix 6 port, which supports named sections but
 450    not an SVR4-style .fini section.  __do_global_dtors can be non-static
 451    in this case because we protect it with -hidden_symbol.  */
 452
 453 void
 454 __do_global_dtors (void)
 455 {
 456   func_ptr *p, f;
 457   for (p = __DTOR_LIST__ + 1; (f = *p); p++)
 458     f ();
 459
 460 #ifdef USE_EH_FRAME_REGISTRY
 461   if (__deregister_frame_info)
 462     __deregister_frame_info (__EH_FRAME_BEGIN__);
 463 #endif
 464 }
 465
 466 #if defined(USE_EH_FRAME_REGISTRY) || defined(JCR_SECTION_NAME)
 467 /* A helper function for __do_global_ctors, which is in crtend.o.  Here
 468    in crtbegin.o, we can reference a couple of symbols not visible there.
 469    Plus, since we're before libgcc.a, we have no problems referencing
 470    functions from there.  */
 471 void
 472 __do_global_ctors_1(void)
 473 {
 474 #ifdef USE_EH_FRAME_REGISTRY
 475   static struct object object;
 476   if (__register_frame_info)
 477     __register_frame_info (__EH_FRAME_BEGIN__, &object);
 478 #endif
 479 #ifdef JCR_SECTION_NAME
 480   if (__JCR_LIST__[0])
 481     {
 482       void (*register_classes) (void *) = _Jv_RegisterClasses;
 483       __asm ("" : "+r" (register_classes));
 484       if (register_classes)
 485         register_classes (__JCR_LIST__);
 486     }
 487 #endif
 488 }
 489 #endif /* USE_EH_FRAME_REGISTRY || JCR_SECTION_NAME */
 490
 491 #else /* ! INIT_SECTION_ASM_OP && ! HAS_INIT_SECTION */
 492 #error "What are you doing with crtstuff.c, then?"
 493 #endif
 494
 495 #elif defined(CRT_END) /* ! CRT_BEGIN */
 496
 497 /* No need for .ctors/.dtors section if linker can place them in
 498    .init_array/.fini_array section.  */
 499 #ifndef USE_INITFINI_ARRAY
 500 /* Put a word containing zero at the end of each of our two lists of function
 501    addresses.  Note that the words defined here go into the .ctors and .dtors
 502    sections of the crtend.o file, and since that file is always linked in
 503    last, these words naturally end up at the very ends of the two lists
 504    contained in these two sections.  */
 505
 506 #ifdef CTOR_LIST_END
 507 CTOR_LIST_END;
 508 #elif defined(CTORS_SECTION_ASM_OP)
 509 /* Hack: force cc1 to switch to .data section early, so that assembling
 510    __CTOR_LIST__ does not undo our behind-the-back change to .ctors.  */
 511 static func_ptr force_to_data[1] __attribute__ ((__used__)) = { };
 512 asm (CTORS_SECTION_ASM_OP);
 513 STATIC func_ptr __CTOR_END__[1]
 514   __attribute__((aligned(sizeof(func_ptr))))
 515   = { (func_ptr) 0 };
 516 #else
 517 STATIC func_ptr __CTOR_END__[1]
 518   __attribute__((section(".ctors"), aligned(sizeof(func_ptr))))
 519   = { (func_ptr) 0 };
 520 #endif
 521
 522 #ifdef DTOR_LIST_END
 523 DTOR_LIST_END;
 524 #elif defined(HIDDEN_DTOR_LIST_END)
 525 #ifdef DTORS_SECTION_ASM_OP
 526 asm (DTORS_SECTION_ASM_OP);
 527 #endif
 528 func_ptr __DTOR_END__[1]
 529   __attribute__ ((used,
 530 #ifndef DTORS_SECTION_ASM_OP
 531                   section(".dtors"),
 532 #endif
 533                   aligned(sizeof(func_ptr)), visibility ("hidden")))
 534   = { (func_ptr) 0 };
 535 #elif defined(DTORS_SECTION_ASM_OP)
 536 asm (DTORS_SECTION_ASM_OP);
 537 STATIC func_ptr __DTOR_END__[1]
 538   __attribute__ ((used, aligned(sizeof(func_ptr))))
 539   = { (func_ptr) 0 };
 540 #else
 541 STATIC func_ptr __DTOR_END__[1]
 542   __attribute__((used, section(".dtors"), aligned(sizeof(func_ptr))))
 543   = { (func_ptr) 0 };
 544 #endif
 545 #endif /* USE_INITFINI_ARRAY */
 546
 547 #ifdef EH_FRAME_SECTION_NAME
 548 /* Terminate the frame unwind info section with a 4byte 0 as a sentinel;
 549    this would be the 'length' field in a real FDE.  */
 550 # if __INT_MAX__ == 2147483647
 551 typedef int int32;
 552 # elif __LONG_MAX__ == 2147483647
 553 typedef long int32;
 554 # elif __SHRT_MAX__ == 2147483647
 555 typedef short int32;
 556 # else
 557 #  error "Missing a 4 byte integer"
 558 # endif
 559 STATIC EH_FRAME_SECTION_CONST int32 __FRAME_END__[]
 560      __attribute__ ((used, section(EH_FRAME_SECTION_NAME),
 561                      aligned(sizeof(int32))))
 562      = { 0 };
 563 #endif /* EH_FRAME_SECTION_NAME */
 564
 565 #ifdef JCR_SECTION_NAME
 566 /* Null terminate the .jcr section array.  */
 567 STATIC void *__JCR_END__[1]
 568    __attribute__ ((used, section(JCR_SECTION_NAME),
 569                    aligned(sizeof(void *))))
 570    = { 0 };
 571 #endif /* JCR_SECTION_NAME */
 572
 573 #ifdef INIT_ARRAY_SECTION_ASM_OP
 574
 575 /* If we are using .init_array, there is nothing to do.  */
 576
 577 #elif defined(INIT_SECTION_ASM_OP)
 578
 579 #ifdef OBJECT_FORMAT_ELF
 580 static void __attribute__((used))
 581 __do_global_ctors_aux (void)
 582 {
 583   func_ptr *p;
 584   for (p = __CTOR_END__ - 1; *p != (func_ptr) -1; p--)
 585     (*p) ();
 586 }
 587
 588 /* Stick a call to __do_global_ctors_aux into the .init section.  */
 589 CRT_CALL_STATIC_FUNCTION (INIT_SECTION_ASM_OP, __do_global_ctors_aux)
 590 #else  /* OBJECT_FORMAT_ELF */
 591
 592 /* Stick the real initialization code, followed by a normal sort of
 593    function epilogue at the very end of the .init section for this
 594    entire root executable file or for this entire shared library file.
 595
 596    Note that we use some tricks here to get *just* the body and just
 597    a function epilogue (but no function prologue) into the .init
 598    section of the crtend.o file.  Specifically, we switch to the .text
 599    section, start to define a function, and then we switch to the .init
 600    section just before the body code.
 601
 602    Earlier on, we put the corresponding function prologue into the .init
 603    section of the crtbegin.o file (which will be linked in first).
 604
 605    Note that we want to invoke all constructors for C++ file-scope static-
 606    storage objects AFTER any other possible initialization actions which
 607    may be performed by the code in the .init section contributions made by
 608    other libraries, etc.  That's because those other initializations may
 609    include setup operations for very primitive things (e.g. initializing
 610    the state of the floating-point coprocessor, etc.) which should be done
 611    before we start to execute any of the user's code.  */
 612
 613 static void
 614 __do_global_ctors_aux (void)    /* prologue goes in .text section */
 615 {
 616   asm (INIT_SECTION_ASM_OP);
 617   DO_GLOBAL_CTORS_BODY;
 618   atexit (__do_global_dtors);
 619 }                               /* epilogue and body go in .init section */
 620
 621 FORCE_CODE_SECTION_ALIGN
 622 asm (TEXT_SECTION_ASM_OP);
 623
 624 #endif /* OBJECT_FORMAT_ELF */
 625
 626 #elif defined(HAS_INIT_SECTION) /* ! INIT_SECTION_ASM_OP */
 627
 628 extern void __do_global_ctors (void);
 629
 630 /* This case is used by the Irix 6 port, which supports named sections but
 631    not an SVR4-style .init section.  __do_global_ctors can be non-static
 632    in this case because we protect it with -hidden_symbol.  */
 633 void
 634 __do_global_ctors (void)
 635 {
 636   func_ptr *p;
 637 #if defined(USE_EH_FRAME_REGISTRY) || defined(JCR_SECTION_NAME)
 638   __do_global_ctors_1();
 639 #endif
 640   for (p = __CTOR_END__ - 1; *p != (func_ptr) -1; p--)
 641     (*p) ();
 642 }
 643
 644 #else /* ! INIT_SECTION_ASM_OP && ! HAS_INIT_SECTION */
 645 #error "What are you doing with crtstuff.c, then?"
 646 #endif
 647
 648 #else /* ! CRT_BEGIN && ! CRT_END */
 649 #error "One of CRT_BEGIN or CRT_END must be defined."
 650 #endif