gcc/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,
   4    1999, 2000, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
   5    Contributed by Ron Guilmette (rfg@monkeys.com).
   6
   7 This file is part of GCC.
   8
   9 GCC is free software; you can redistribute it and/or modify it under
  10 the terms of the GNU General Public License as published by the Free
  11 Software Foundation; either version 2, or (at your option) any later
  12 version.
  13
  14 In addition to the permissions in the GNU General Public License, the
  15 Free Software Foundation gives you unlimited permission to link the
  16 compiled version of this file into combinations with other programs,
  17 and to distribute those combinations without any restriction coming
  18 from the use of this file.  (The General Public License restrictions
  19 do apply in other respects; for example, they cover modification of
  20 the file, and distribution when not linked into a combine
  21 executable.)
  22
  23 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  24 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  25 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  26 for more details.
  27
  28 You should have received a copy of the GNU General Public License
  29 along with GCC; see the file COPYING.  If not, write to the Free
  30 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
  31 02110-1301, USA.  */
  32
  33 /* This file is a bit like libgcc2.c in that it is compiled
  34    multiple times and yields multiple .o files.
  35
  36    This file is useful on target machines where the object file format
  37    supports multiple "user-defined" sections (e.g. COFF, ELF, ROSE).  On
  38    such systems, this file allows us to avoid running collect (or any
  39    other such slow and painful kludge).  Additionally, if the target
  40    system supports a .init section, this file allows us to support the
  41    linking of C++ code with a non-C++ main program.
  42
  43    Note that if INIT_SECTION_ASM_OP is defined in the tm.h file, then
  44    this file *will* make use of the .init section.  If that symbol is
  45    not defined however, then the .init section will not be used.
  46
  47    Currently, only ELF and COFF are supported.  It is likely however that
  48    ROSE could also be supported, if someone was willing to do the work to
  49    make whatever (small?) adaptations are needed.  (Some work may be
  50    needed on the ROSE assembler and linker also.)
  51
  52    This file must be compiled with gcc.  */
  53
  54 /* Target machine header files require this define. */
  55 #define IN_LIBGCC2
  56
  57 /* FIXME: Including auto-host is incorrect, but until we have
  58    identified the set of defines that need to go into auto-target.h,
  59    this will have to do.  */
  60 #include "auto-host.h"
  61 #undef gid_t
  62 #undef pid_t
  63 #undef rlim_t
  64 #undef ssize_t
  65 #undef uid_t
  66 #undef vfork
  67 #include "tconfig.h"
  68 #include "tsystem.h"
  69 #include "coretypes.h"
  70 #include "tm.h"
  71 #include "unwind-dw2-fde.h"
  72
  73 #ifndef FORCE_CODE_SECTION_ALIGN
  74 # define FORCE_CODE_SECTION_ALIGN
  75 #endif
  76
  77 #ifndef CRT_CALL_STATIC_FUNCTION
  78 # define CRT_CALL_STATIC_FUNCTION(SECTION_OP, FUNC)     \
  79 static void __attribute__((__used__))                   \
  80 call_ ## FUNC (void)                                    \
  81 {                                                       \
  82   asm (SECTION_OP);                                     \
  83   FUNC ();                                              \
  84   FORCE_CODE_SECTION_ALIGN                              \
  85   asm (TEXT_SECTION_ASM_OP);                            \
  86 }
  87 #endif
  88
  89 #if defined(OBJECT_FORMAT_ELF) \
  90     && !defined(OBJECT_FORMAT_FLAT) \
  91     && defined(HAVE_LD_EH_FRAME_HDR) \
  92     && !defined(inhibit_libc) && !defined(CRTSTUFFT_O) \
  93     && defined(__GLIBC__) && __GLIBC__ >= 2
  94 #include <link.h>
  95 # if (__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 2) \
  96      || (__GLIBC__ == 2 && __GLIBC_MINOR__ == 2 && defined(DT_CONFIG)))
  97 #  define USE_PT_GNU_EH_FRAME
  98 # endif
  99 #endif
 100 #if defined(EH_FRAME_SECTION_NAME) && !defined(USE_PT_GNU_EH_FRAME)
 101 # define USE_EH_FRAME_REGISTRY
 102 #endif
 103 #if defined(EH_FRAME_SECTION_NAME) && EH_TABLES_CAN_BE_READ_ONLY
 104 # define EH_FRAME_SECTION_CONST const
 105 #else
 106 # define EH_FRAME_SECTION_CONST
 107 #endif
 108
 109 /* We do not want to add the weak attribute to the declarations of these
 110    routines in unwind-dw2-fde.h because that will cause the definition of
 111    these symbols to be weak as well.
 112
 113    This exposes a core issue, how to handle creating weak references vs
 114    how to create weak definitions.  Either we have to have the definition
 115    of TARGET_WEAK_ATTRIBUTE be conditional in the shared header files or
 116    have a second declaration if we want a function's references to be weak,
 117    but not its definition.
 118
 119    Making TARGET_WEAK_ATTRIBUTE conditional seems like a good solution until
 120    one thinks about scaling to larger problems -- i.e., the condition under
 121    which TARGET_WEAK_ATTRIBUTE is active will eventually get far too
 122    complicated.
 123
 124    So, we take an approach similar to #pragma weak -- we have a second
 125    declaration for functions that we want to have weak references.
 126
 127    Neither way is particularly good.  */
 128
 129 /* References to __register_frame_info and __deregister_frame_info should
 130    be weak in this file if at all possible.  */
 131 extern void __register_frame_info (const void *, struct object *)
 132                                   TARGET_ATTRIBUTE_WEAK;
 133 extern void __register_frame_info_bases (const void *, struct object *,
 134                                          void *, void *)
 135                                   TARGET_ATTRIBUTE_WEAK;
 136 extern void *__deregister_frame_info (const void *)
 137                                      TARGET_ATTRIBUTE_WEAK;
 138 extern void *__deregister_frame_info_bases (const void *)
 139                                      TARGET_ATTRIBUTE_WEAK;
 140 extern void __do_global_ctors_1 (void);
 141
 142 /* Likewise for _Jv_RegisterClasses.  */
 143 extern void _Jv_RegisterClasses (void *) TARGET_ATTRIBUTE_WEAK;
 144
 145 #ifdef OBJECT_FORMAT_ELF
 146
 147 /*  Declare a pointer to void function type.  */
 148 typedef void (*func_ptr) (void);
 149 #define STATIC static
 150
 151 #else  /* OBJECT_FORMAT_ELF */
 152
 153 #include "gbl-ctors.h"
 154
 155 #define STATIC
 156
 157 #endif /* OBJECT_FORMAT_ELF */
 158
 159 #ifdef CRT_BEGIN
 160
 161 /* NOTE:  In order to be able to support SVR4 shared libraries, we arrange
 162    to have one set of symbols { __CTOR_LIST__, __DTOR_LIST__, __CTOR_END__,
 163    __DTOR_END__ } per root executable and also one set of these symbols
 164    per shared library.  So in any given whole process image, we may have
 165    multiple definitions of each of these symbols.  In order to prevent
 166    these definitions from conflicting with one another, and in order to
 167    ensure that the proper lists are used for the initialization/finalization
 168    of each individual shared library (respectively), we give these symbols
 169    only internal (i.e. `static') linkage, and we also make it a point to
 170    refer to only the __CTOR_END__ symbol in crtend.o and the __DTOR_LIST__
 171    symbol in crtbegin.o, where they are defined.  */
 172
 173 /* The -1 is a flag to __do_global_[cd]tors indicating that this table
 174    does not start with a count of elements.  */
 175 #ifdef CTOR_LIST_BEGIN
 176 CTOR_LIST_BEGIN;
 177 #elif defined(CTORS_SECTION_ASM_OP)
 178 /* Hack: force cc1 to switch to .data section early, so that assembling
 179    __CTOR_LIST__ does not undo our behind-the-back change to .ctors.  */
 180 static func_ptr force_to_data[1] __attribute__ ((__unused__)) = { };
 181 asm (CTORS_SECTION_ASM_OP);
 182 STATIC func_ptr __CTOR_LIST__[1]
 183   __attribute__ ((__unused__, aligned(sizeof(func_ptr))))
 184   = { (func_ptr) (-1) };
 185 #else
 186 STATIC func_ptr __CTOR_LIST__[1]
 187   __attribute__ ((__unused__, section(".ctors"), aligned(sizeof(func_ptr))))
 188   = { (func_ptr) (-1) };
 189 #endif /* __CTOR_LIST__ alternatives */
 190
 191 #ifdef DTOR_LIST_BEGIN
 192 DTOR_LIST_BEGIN;
 193 #elif defined(DTORS_SECTION_ASM_OP)
 194 asm (DTORS_SECTION_ASM_OP);
 195 STATIC func_ptr __DTOR_LIST__[1]
 196   __attribute__ ((aligned(sizeof(func_ptr))))
 197   = { (func_ptr) (-1) };
 198 #else
 199 STATIC func_ptr __DTOR_LIST__[1]
 200   __attribute__((section(".dtors"), aligned(sizeof(func_ptr))))
 201   = { (func_ptr) (-1) };
 202 #endif /* __DTOR_LIST__ alternatives */
 203
 204 #ifdef USE_EH_FRAME_REGISTRY
 205 /* Stick a label at the beginning of the frame unwind info so we can register
 206    and deregister it with the exception handling library code.  */
 207 STATIC EH_FRAME_SECTION_CONST char __EH_FRAME_BEGIN__[]
 208      __attribute__((section(EH_FRAME_SECTION_NAME), aligned(4)))
 209      = { };
 210 #endif /* USE_EH_FRAME_REGISTRY */
 211
 212 #ifdef JCR_SECTION_NAME
 213 /* Stick a label at the beginning of the java class registration info
 214    so we can register them properly.  */
 215 STATIC void *__JCR_LIST__[]
 216   __attribute__ ((unused, section(JCR_SECTION_NAME), aligned(sizeof(void*))))
 217   = { };
 218 #endif /* JCR_SECTION_NAME */
 219
 220 #if defined(INIT_SECTION_ASM_OP) || defined(INIT_ARRAY_SECTION_ASM_OP)
 221
 222 #ifdef OBJECT_FORMAT_ELF
 223
 224 /* Declare the __dso_handle variable.  It should have a unique value
 225    in every shared-object; in a main program its value is zero.  The
 226    object should in any case be protected.  This means the instance
 227    in one DSO or the main program is not used in another object.  The
 228    dynamic linker takes care of this.  */
 229
 230 #ifdef TARGET_LIBGCC_SDATA_SECTION
 231 extern void *__dso_handle __attribute__ ((__section__ (TARGET_LIBGCC_SDATA_SECTION)));
 232 #endif
 233 #ifdef HAVE_GAS_HIDDEN
 234 extern void *__dso_handle __attribute__ ((__visibility__ ("hidden")));
 235 #endif
 236 #ifdef CRTSTUFFS_O
 237 void *__dso_handle = &__dso_handle;
 238 #else
 239 void *__dso_handle = 0;
 240 #endif
 241
 242 /* The __cxa_finalize function may not be available so we use only a
 243    weak declaration.  */
 244 extern void __cxa_finalize (void *) TARGET_ATTRIBUTE_WEAK;
 245
 246 /* Run all the global destructors on exit from the program.  */
 247
 248 /* Some systems place the number of pointers in the first word of the
 249    table.  On SVR4 however, that word is -1.  In all cases, the table is
 250    null-terminated.  On SVR4, we start from the beginning of the list and
 251    invoke each per-compilation-unit destructor routine in order
 252    until we find that null.
 253
 254    Note that this function MUST be static.  There will be one of these
 255    functions in each root executable and one in each shared library, but
 256    although they all have the same code, each one is unique in that it
 257    refers to one particular associated `__DTOR_LIST__' which belongs to the
 258    same particular root executable or shared library file.
 259
 260    On some systems, this routine is run more than once from the .fini,
 261    when exit is called recursively, so we arrange to remember where in
 262    the list we left off processing, and we resume at that point,
 263    should we be re-invoked.  */
 264
 265 static void __attribute__((used))
 266 __do_global_dtors_aux (void)
 267 {
 268 #ifndef FINI_ARRAY_SECTION_ASM_OP
 269   static func_ptr *p = __DTOR_LIST__ + 1;
 270   func_ptr f;
 271 #endif /* !defined(FINI_ARRAY_SECTION_ASM_OP)  */
 272   static _Bool completed;
 273
 274   if (__builtin_expect (completed, 0))
 275     return;
 276
 277 #ifdef CRTSTUFFS_O
 278   if (__cxa_finalize)
 279     __cxa_finalize (__dso_handle);
 280 #endif
 281
 282 #ifdef FINI_ARRAY_SECTION_ASM_OP
 283   /* If we are using .fini_array then destructors will be run via that
 284      mechanism.  */
 285 #else /* !defined (FINI_ARRAY_SECTION_ASM_OP) */
 286   while ((f = *p))
 287     {
 288       p++;
 289       f ();
 290     }
 291 #endif /* !defined(FINI_ARRAY_SECTION_ASM_OP) */
 292
 293 #ifdef USE_EH_FRAME_REGISTRY
 294 #ifdef CRT_GET_RFIB_DATA
 295   /* If we used the new __register_frame_info_bases interface,
 296      make sure that we deregister from the same place.  */
 297   if (__deregister_frame_info_bases)
 298     __deregister_frame_info_bases (__EH_FRAME_BEGIN__);
 299 #else
 300   if (__deregister_frame_info)
 301     __deregister_frame_info (__EH_FRAME_BEGIN__);
 302 #endif
 303 #endif
 304
 305   completed = 1;
 306 }
 307
 308 /* Stick a call to __do_global_dtors_aux into the .fini section.  */
 309 #ifdef FINI_SECTION_ASM_OP
 310 CRT_CALL_STATIC_FUNCTION (FINI_SECTION_ASM_OP, __do_global_dtors_aux)
 311 #else /* !defined(FINI_SECTION_ASM_OP) */
 312 static func_ptr __do_global_dtors_aux_fini_array_entry[]
 313   __attribute__ ((__unused__, section(".fini_array")))
 314   = { __do_global_dtors_aux };
 315 #endif /* !defined(FINI_SECTION_ASM_OP) */
 316
 317 #if defined(USE_EH_FRAME_REGISTRY) || defined(JCR_SECTION_NAME)
 318 /* Stick a call to __register_frame_info into the .init section.  For some
 319    reason calls with no arguments work more reliably in .init, so stick the
 320    call in another function.  */
 321
 322 static void __attribute__((used))
 323 frame_dummy (void)
 324 {
 325 #ifdef USE_EH_FRAME_REGISTRY
 326   static struct object object;
 327 #ifdef CRT_GET_RFIB_DATA
 328   void *tbase, *dbase;
 329   tbase = 0;
 330   CRT_GET_RFIB_DATA (dbase);
 331   if (__register_frame_info_bases)
 332     __register_frame_info_bases (__EH_FRAME_BEGIN__, &object, tbase, dbase);
 333 #else
 334   if (__register_frame_info)
 335     __register_frame_info (__EH_FRAME_BEGIN__, &object);
 336 #endif /* CRT_GET_RFIB_DATA */
 337 #endif /* USE_EH_FRAME_REGISTRY */
 338 #ifdef JCR_SECTION_NAME
 339   if (__JCR_LIST__[0])
 340     {
 341       void (*register_classes) (void *) = _Jv_RegisterClasses;
 342       __asm ("" : "+r" (register_classes));
 343       if (register_classes)
 344         register_classes (__JCR_LIST__);
 345     }
 346 #endif /* JCR_SECTION_NAME */
 347 }
 348
 349 #ifdef INIT_SECTION_ASM_OP
 350 CRT_CALL_STATIC_FUNCTION (INIT_SECTION_ASM_OP, frame_dummy)
 351 #else /* defined(INIT_SECTION_ASM_OP) */
 352 static func_ptr __frame_dummy_init_array_entry[]
 353   __attribute__ ((__unused__, section(".init_array")))
 354   = { frame_dummy };
 355 #endif /* !defined(INIT_SECTION_ASM_OP) */
 356 #endif /* USE_EH_FRAME_REGISTRY || JCR_SECTION_NAME */
 357
 358 #else  /* OBJECT_FORMAT_ELF */
 359
 360 /* The function __do_global_ctors_aux is compiled twice (once in crtbegin.o
 361    and once in crtend.o).  It must be declared static to avoid a link
 362    error.  Here, we define __do_global_ctors as an externally callable
 363    function.  It is externally callable so that __main can invoke it when
 364    INVOKE__main is defined.  This has the additional effect of forcing cc1
 365    to switch to the .text section.  */
 366
 367 static void __do_global_ctors_aux (void);
 368 void
 369 __do_global_ctors (void)
 370 {
 371 #ifdef INVOKE__main
 372   /* If __main won't actually call __do_global_ctors then it doesn't matter
 373      what's inside the function.  The inside of __do_global_ctors_aux is
 374      called automatically in that case.  And the Alliant fx2800 linker
 375      crashes on this reference.  So prevent the crash.  */
 376   __do_global_ctors_aux ();
 377 #endif
 378 }
 379
 380 asm (INIT_SECTION_ASM_OP);      /* cc1 doesn't know that we are switching! */
 381
 382 /* A routine to invoke all of the global constructors upon entry to the
 383    program.  We put this into the .init section (for systems that have
 384    such a thing) so that we can properly perform the construction of
 385    file-scope static-storage C++ objects within shared libraries.  */
 386
 387 static void __attribute__((used))
 388 __do_global_ctors_aux (void)    /* prologue goes in .init section */
 389 {
 390   FORCE_CODE_SECTION_ALIGN      /* explicit align before switch to .text */
 391   asm (TEXT_SECTION_ASM_OP);    /* don't put epilogue and body in .init */
 392   DO_GLOBAL_CTORS_BODY;
 393   atexit (__do_global_dtors);
 394 }
 395
 396 #endif /* OBJECT_FORMAT_ELF */
 397
 398 #elif defined(HAS_INIT_SECTION) /* ! INIT_SECTION_ASM_OP */
 399
 400 extern void __do_global_dtors (void);
 401
 402 /* This case is used by the Irix 6 port, which supports named sections but
 403    not an SVR4-style .fini section.  __do_global_dtors can be non-static
 404    in this case because we protect it with -hidden_symbol.  */
 405
 406 void
 407 __do_global_dtors (void)
 408 {
 409   func_ptr *p, f;
 410   for (p = __DTOR_LIST__ + 1; (f = *p); p++)
 411     f ();
 412
 413 #ifdef USE_EH_FRAME_REGISTRY
 414   if (__deregister_frame_info)
 415     __deregister_frame_info (__EH_FRAME_BEGIN__);
 416 #endif
 417 }
 418
 419 #if defined(USE_EH_FRAME_REGISTRY) || defined(JCR_SECTION_NAME)
 420 /* A helper function for __do_global_ctors, which is in crtend.o.  Here
 421    in crtbegin.o, we can reference a couple of symbols not visible there.
 422    Plus, since we're before libgcc.a, we have no problems referencing
 423    functions from there.  */
 424 void
 425 __do_global_ctors_1(void)
 426 {
 427 #ifdef USE_EH_FRAME_REGISTRY
 428   static struct object object;
 429   if (__register_frame_info)
 430     __register_frame_info (__EH_FRAME_BEGIN__, &object);
 431 #endif
 432 #ifdef JCR_SECTION_NAME
 433   if (__JCR_LIST__[0])
 434     {
 435       void (*register_classes) (void *) = _Jv_RegisterClasses;
 436       __asm ("" : "+r" (register_classes));
 437       if (register_classes)
 438         register_classes (__JCR_LIST__);
 439     }
 440 #endif
 441 }
 442 #endif /* USE_EH_FRAME_REGISTRY || JCR_SECTION_NAME */
 443
 444 #else /* ! INIT_SECTION_ASM_OP && ! HAS_INIT_SECTION */
 445 #error "What are you doing with crtstuff.c, then?"
 446 #endif
 447
 448 #elif defined(CRT_END) /* ! CRT_BEGIN */
 449
 450 /* Put a word containing zero at the end of each of our two lists of function
 451    addresses.  Note that the words defined here go into the .ctors and .dtors
 452    sections of the crtend.o file, and since that file is always linked in
 453    last, these words naturally end up at the very ends of the two lists
 454    contained in these two sections.  */
 455
 456 #ifdef CTOR_LIST_END
 457 CTOR_LIST_END;
 458 #elif defined(CTORS_SECTION_ASM_OP)
 459 /* Hack: force cc1 to switch to .data section early, so that assembling
 460    __CTOR_LIST__ does not undo our behind-the-back change to .ctors.  */
 461 static func_ptr force_to_data[1] __attribute__ ((__unused__)) = { };
 462 asm (CTORS_SECTION_ASM_OP);
 463 STATIC func_ptr __CTOR_END__[1]
 464   __attribute__((aligned(sizeof(func_ptr))))
 465   = { (func_ptr) 0 };
 466 #else
 467 STATIC func_ptr __CTOR_END__[1]
 468   __attribute__((section(".ctors"), aligned(sizeof(func_ptr))))
 469   = { (func_ptr) 0 };
 470 #endif
 471
 472 #ifdef DTOR_LIST_END
 473 DTOR_LIST_END;
 474 #elif defined(DTORS_SECTION_ASM_OP)
 475 asm (DTORS_SECTION_ASM_OP);
 476 STATIC func_ptr __DTOR_END__[1]
 477   __attribute__ ((unused, aligned(sizeof(func_ptr))))
 478   = { (func_ptr) 0 };
 479 #else
 480 STATIC func_ptr __DTOR_END__[1]
 481   __attribute__((unused, section(".dtors"), aligned(sizeof(func_ptr))))
 482   = { (func_ptr) 0 };
 483 #endif
 484
 485 #ifdef EH_FRAME_SECTION_NAME
 486 /* Terminate the frame unwind info section with a 4byte 0 as a sentinel;
 487    this would be the 'length' field in a real FDE.  */
 488 # if __INT_MAX__ == 2147483647
 489 typedef int int32;
 490 # elif __LONG_MAX__ == 2147483647
 491 typedef long int32;
 492 # elif __SHRT_MAX__ == 2147483647
 493 typedef short int32;
 494 # else
 495 #  error "Missing a 4 byte integer"
 496 # endif
 497 STATIC EH_FRAME_SECTION_CONST int32 __FRAME_END__[]
 498      __attribute__ ((unused, section(EH_FRAME_SECTION_NAME),
 499                      aligned(sizeof(int32))))
 500      = { 0 };
 501 #endif /* EH_FRAME_SECTION_NAME */
 502
 503 #ifdef JCR_SECTION_NAME
 504 /* Null terminate the .jcr section array.  */
 505 STATIC void *__JCR_END__[1]
 506    __attribute__ ((unused, section(JCR_SECTION_NAME),
 507                    aligned(sizeof(void *))))
 508    = { 0 };
 509 #endif /* JCR_SECTION_NAME */
 510
 511 #ifdef INIT_ARRAY_SECTION_ASM_OP
 512
 513 /* If we are using .init_array, there is nothing to do.  */
 514
 515 #elif defined(INIT_SECTION_ASM_OP)
 516
 517 #ifdef OBJECT_FORMAT_ELF
 518 static void __attribute__((used))
 519 __do_global_ctors_aux (void)
 520 {
 521   func_ptr *p;
 522   for (p = __CTOR_END__ - 1; *p != (func_ptr) -1; p--)
 523     (*p) ();
 524 }
 525
 526 /* Stick a call to __do_global_ctors_aux into the .init section.  */
 527 CRT_CALL_STATIC_FUNCTION (INIT_SECTION_ASM_OP, __do_global_ctors_aux)
 528 #else  /* OBJECT_FORMAT_ELF */
 529
 530 /* Stick the real initialization code, followed by a normal sort of
 531    function epilogue at the very end of the .init section for this
 532    entire root executable file or for this entire shared library file.
 533
 534    Note that we use some tricks here to get *just* the body and just
 535    a function epilogue (but no function prologue) into the .init
 536    section of the crtend.o file.  Specifically, we switch to the .text
 537    section, start to define a function, and then we switch to the .init
 538    section just before the body code.
 539
 540    Earlier on, we put the corresponding function prologue into the .init
 541    section of the crtbegin.o file (which will be linked in first).
 542
 543    Note that we want to invoke all constructors for C++ file-scope static-
 544    storage objects AFTER any other possible initialization actions which
 545    may be performed by the code in the .init section contributions made by
 546    other libraries, etc.  That's because those other initializations may
 547    include setup operations for very primitive things (e.g. initializing
 548    the state of the floating-point coprocessor, etc.) which should be done
 549    before we start to execute any of the user's code.  */
 550
 551 static void
 552 __do_global_ctors_aux (void)    /* prologue goes in .text section */
 553 {
 554   asm (INIT_SECTION_ASM_OP);
 555   DO_GLOBAL_CTORS_BODY;
 556   atexit (__do_global_dtors);
 557 }                               /* epilogue and body go in .init section */
 558
 559 FORCE_CODE_SECTION_ALIGN
 560 asm (TEXT_SECTION_ASM_OP);
 561
 562 #endif /* OBJECT_FORMAT_ELF */
 563
 564 #elif defined(HAS_INIT_SECTION) /* ! INIT_SECTION_ASM_OP */
 565
 566 extern void __do_global_ctors (void);
 567
 568 /* This case is used by the Irix 6 port, which supports named sections but
 569    not an SVR4-style .init section.  __do_global_ctors can be non-static
 570    in this case because we protect it with -hidden_symbol.  */
 571 void
 572 __do_global_ctors (void)
 573 {
 574   func_ptr *p;
 575 #if defined(USE_EH_FRAME_REGISTRY) || defined(JCR_SECTION_NAME)
 576   __do_global_ctors_1();
 577 #endif
 578   for (p = __CTOR_END__ - 1; *p != (func_ptr) -1; p--)
 579     (*p) ();
 580 }
 581
 582 #else /* ! INIT_SECTION_ASM_OP && ! HAS_INIT_SECTION */
 583 #error "What are you doing with crtstuff.c, then?"
 584 #endif
 585
 586 #else /* ! CRT_BEGIN && ! CRT_END */
 587 #error "One of CRT_BEGIN or CRT_END must be defined."
 588 #endif