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 Free Software Foundation, Inc. 5 Contributed by Ron Guilmette (rfg@monkeys.com). 6 7This file is part of GCC. 8 9GCC is free software; you can redistribute it and/or modify it under 10the terms of the GNU General Public License as published by the Free 11Software Foundation; either version 3, or (at your option) any later 12version. 13 14GCC is distributed in the hope that it will be useful, but WITHOUT ANY 15WARRANTY; without even the implied warranty of MERCHANTABILITY or 16FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 17for more details. 18 19Under Section 7 of GPL version 3, you are granted additional 20permissions described in the GCC Runtime Library Exception, version 213.1, as published by the Free Software Foundation. 22 23You should have received a copy of the GNU General Public License and 24a copy of the GCC Runtime Library Exception along with this program; 25see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 26<http://www.gnu.org/licenses/>. */ 27 28/* This file is a bit like libgcc2.c in that it is compiled 29 multiple times and yields multiple .o files. 30 31 This file is useful on target machines where the object file format 32 supports multiple "user-defined" sections (e.g. COFF, ELF, ROSE). On 33 such systems, this file allows us to avoid running collect (or any 34 other such slow and painful kludge). Additionally, if the target 35 system supports a .init section, this file allows us to support the 36 linking of C++ code with a non-C++ main program. 37 38 Note that if INIT_SECTION_ASM_OP is defined in the tm.h file, then 39 this file *will* make use of the .init section. If that symbol is 40 not defined however, then the .init section will not be used. 41 42 Currently, only ELF and COFF are supported. It is likely however that 43 ROSE could also be supported, if someone was willing to do the work to 44 make whatever (small?) adaptations are needed. (Some work may be 45 needed on the ROSE assembler and linker also.) 46 47 This file must be compiled with gcc. */ 48 49/* Target machine header files require this define. */ 50#define IN_LIBGCC2 51 52/* FIXME: Including auto-host is incorrect, but until we have 53 identified the set of defines that need to go into auto-target.h, 54 this will have to do. */ 55#include "auto-host.h" 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 "unwind-dw2-fde.h" 65 66#ifndef FORCE_CODE_SECTION_ALIGN 67# define FORCE_CODE_SECTION_ALIGN 68#endif 69 70#ifndef CRT_CALL_STATIC_FUNCTION 71# define CRT_CALL_STATIC_FUNCTION(SECTION_OP, FUNC) \ 72static void __attribute__((__used__)) \ 73call_ ## FUNC (void) \ 74{ \ 75 asm (SECTION_OP); \ 76 FUNC (); \ 77 FORCE_CODE_SECTION_ALIGN \ 78 asm (TEXT_SECTION_ASM_OP); \ 79} 80#endif 81 82#if defined(OBJECT_FORMAT_ELF) \ 83 && !defined(OBJECT_FORMAT_FLAT) \ 84 && defined(HAVE_LD_EH_FRAME_HDR) \ 85 && !defined(inhibit_libc) && !defined(CRTSTUFFT_O) \ 86 && defined(__FreeBSD__) && __FreeBSD__ >= 7 87#include <link.h> 88# define USE_PT_GNU_EH_FRAME 89#endif 90 91#if defined(OBJECT_FORMAT_ELF) \ 92 && !defined(OBJECT_FORMAT_FLAT) \ 93 && defined(HAVE_LD_EH_FRAME_HDR) \ 94 && !defined(inhibit_libc) && !defined(CRTSTUFFT_O) \ 95 && defined(__NetBSD__) 96#include <link.h> 97# define USE_PT_GNU_EH_FRAME 98#endif 99 100#if defined(OBJECT_FORMAT_ELF) \ 101 && !defined(OBJECT_FORMAT_FLAT) \ 102 && defined(HAVE_LD_EH_FRAME_HDR) \ 103 && !defined(inhibit_libc) && !defined(CRTSTUFFT_O) \ 104 && defined(__GLIBC__) && __GLIBC__ >= 2 105#include <link.h> 106/* uClibc pretends to be glibc 2.2 and DT_CONFIG is defined in its link.h. 107 But it doesn't use PT_GNU_EH_FRAME ELF segment currently. */ 108# if !defined(__UCLIBC__) \ 109 && (__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 2) \ 110 || (__GLIBC__ == 2 && __GLIBC_MINOR__ == 2 && defined(DT_CONFIG))) 111# define USE_PT_GNU_EH_FRAME 112# endif 113#endif 114#if defined(EH_FRAME_SECTION_NAME) && !defined(USE_PT_GNU_EH_FRAME) 115# define USE_EH_FRAME_REGISTRY 116#endif 117#if defined(EH_FRAME_SECTION_NAME) && EH_TABLES_CAN_BE_READ_ONLY 118# define EH_FRAME_SECTION_CONST const 119#else 120# define EH_FRAME_SECTION_CONST 121#endif 122 123#if !defined(DTOR_LIST_END) && defined(OBJECT_FORMAT_ELF) \ 124 && defined(HAVE_GAS_HIDDEN) && !defined(FINI_ARRAY_SECTION_ASM_OP) 125# define HIDDEN_DTOR_LIST_END 126#endif 127 128/* We do not want to add the weak attribute to the declarations of these 129 routines in unwind-dw2-fde.h because that will cause the definition of 130 these symbols to be weak as well. 131 132 This exposes a core issue, how to handle creating weak references vs 133 how to create weak definitions. Either we have to have the definition 134 of TARGET_WEAK_ATTRIBUTE be conditional in the shared header files or 135 have a second declaration if we want a function's references to be weak, 136 but not its definition. 137 138 Making TARGET_WEAK_ATTRIBUTE conditional seems like a good solution until 139 one thinks about scaling to larger problems -- i.e., the condition under 140 which TARGET_WEAK_ATTRIBUTE is active will eventually get far too 141 complicated. 142 143 So, we take an approach similar to #pragma weak -- we have a second 144 declaration for functions that we want to have weak references. 145 146 Neither way is particularly good. */ 147 148/* References to __register_frame_info and __deregister_frame_info should 149 be weak in this file if at all possible. */ 150extern void __register_frame_info (const void *, struct object *) 151 TARGET_ATTRIBUTE_WEAK; 152extern void __register_frame_info_bases (const void *, struct object *, 153 void *, void *) 154 TARGET_ATTRIBUTE_WEAK; 155extern void *__deregister_frame_info (const void *) 156 TARGET_ATTRIBUTE_WEAK; 157extern void *__deregister_frame_info_bases (const void *) 158 TARGET_ATTRIBUTE_WEAK; 159extern void __do_global_ctors_1 (void); 160 161/* Likewise for _Jv_RegisterClasses. */ 162extern void _Jv_RegisterClasses (void *) TARGET_ATTRIBUTE_WEAK; 163 164#ifdef OBJECT_FORMAT_ELF 165 166/* Declare a pointer to void function type. */ 167typedef void (*func_ptr) (void); 168#define STATIC static 169 170#else /* OBJECT_FORMAT_ELF */ 171 172#include "gbl-ctors.h" 173 174#define STATIC 175 176#endif /* OBJECT_FORMAT_ELF */ 177 178#ifdef CRT_BEGIN 179 180/* NOTE: In order to be able to support SVR4 shared libraries, we arrange 181 to have one set of symbols { __CTOR_LIST__, __DTOR_LIST__, __CTOR_END__, 182 __DTOR_END__ } per root executable and also one set of these symbols 183 per shared library. So in any given whole process image, we may have 184 multiple definitions of each of these symbols. In order to prevent 185 these definitions from conflicting with one another, and in order to 186 ensure that the proper lists are used for the initialization/finalization 187 of each individual shared library (respectively), we give these symbols 188 only internal (i.e. `static') linkage, and we also make it a point to 189 refer to only the __CTOR_END__ symbol in crtend.o and the __DTOR_LIST__ 190 symbol in crtbegin.o, where they are defined. */ 191 192/* The -1 is a flag to __do_global_[cd]tors indicating that this table 193 does not start with a count of elements. */ 194#ifdef CTOR_LIST_BEGIN 195CTOR_LIST_BEGIN; 196#elif defined(CTORS_SECTION_ASM_OP) 197/* Hack: force cc1 to switch to .data section early, so that assembling 198 __CTOR_LIST__ does not undo our behind-the-back change to .ctors. */ 199static func_ptr force_to_data[1] __attribute__ ((__unused__)) = { }; 200asm (CTORS_SECTION_ASM_OP); 201STATIC func_ptr __CTOR_LIST__[1] 202 __attribute__ ((__unused__, aligned(sizeof(func_ptr)))) 203 = { (func_ptr) (-1) }; 204#else 205STATIC func_ptr __CTOR_LIST__[1] 206 __attribute__ ((__unused__, section(".ctors"), aligned(sizeof(func_ptr)))) 207 = { (func_ptr) (-1) }; 208#endif /* __CTOR_LIST__ alternatives */ 209 210#ifdef DTOR_LIST_BEGIN 211DTOR_LIST_BEGIN; 212#elif defined(DTORS_SECTION_ASM_OP) 213asm (DTORS_SECTION_ASM_OP); 214STATIC func_ptr __DTOR_LIST__[1] 215 __attribute__ ((aligned(sizeof(func_ptr)))) 216 = { (func_ptr) (-1) }; 217#else 218STATIC func_ptr __DTOR_LIST__[1] 219 __attribute__((section(".dtors"), aligned(sizeof(func_ptr)))) 220 = { (func_ptr) (-1) }; 221#endif /* __DTOR_LIST__ alternatives */ 222 223#ifdef USE_EH_FRAME_REGISTRY 224/* Stick a label at the beginning of the frame unwind info so we can register 225 and deregister it with the exception handling library code. */ 226STATIC EH_FRAME_SECTION_CONST char __EH_FRAME_BEGIN__[] 227 __attribute__((section(EH_FRAME_SECTION_NAME), aligned(4))) 228 = { }; 229#endif /* USE_EH_FRAME_REGISTRY */ 230 231#ifdef JCR_SECTION_NAME 232/* Stick a label at the beginning of the java class registration info 233 so we can register them properly. */ 234STATIC void *__JCR_LIST__[] 235 __attribute__ ((unused, section(JCR_SECTION_NAME), aligned(sizeof(void*)))) 236 = { }; 237#endif /* JCR_SECTION_NAME */ 238 239#if defined(INIT_SECTION_ASM_OP) || defined(INIT_ARRAY_SECTION_ASM_OP) 240 241#ifdef OBJECT_FORMAT_ELF 242 243/* Declare the __dso_handle variable. It should have a unique value 244 in every shared-object; in a main program its value is zero. The 245 object should in any case be protected. This means the instance 246 in one DSO or the main program is not used in another object. The 247 dynamic linker takes care of this. */ 248 249#ifdef TARGET_LIBGCC_SDATA_SECTION 250extern void *__dso_handle __attribute__ ((__section__ (TARGET_LIBGCC_SDATA_SECTION))); 251#endif 252#ifdef HAVE_GAS_HIDDEN 253extern void *__dso_handle __attribute__ ((__visibility__ ("hidden"))); 254#endif 255#ifdef CRTSTUFFS_O 256void *__dso_handle = &__dso_handle; 257#else 258void *__dso_handle = 0; 259#endif 260 261/* The __cxa_finalize function may not be available so we use only a 262 weak declaration. */ 263extern void __cxa_finalize (void *) TARGET_ATTRIBUTE_WEAK; 264 265/* Run all the global destructors on exit from the program. */ 266 267/* Some systems place the number of pointers in the first word of the 268 table. On SVR4 however, that word is -1. In all cases, the table is 269 null-terminated. On SVR4, we start from the beginning of the list and 270 invoke each per-compilation-unit destructor routine in order 271 until we find that null. 272 273 Note that this function MUST be static. There will be one of these 274 functions in each root executable and one in each shared library, but 275 although they all have the same code, each one is unique in that it 276 refers to one particular associated `__DTOR_LIST__' which belongs to the 277 same particular root executable or shared library file. 278 279 On some systems, this routine is run more than once from the .fini, 280 when exit is called recursively, so we arrange to remember where in 281 the list we left off processing, and we resume at that point, 282 should we be re-invoked. */ 283 284static void __attribute__((used)) 285__do_global_dtors_aux (void) 286{ 287 static _Bool completed; 288 289 if (__builtin_expect (completed, 0)) 290 return; 291 292#ifdef CRTSTUFFS_O 293 if (__cxa_finalize) 294 __cxa_finalize (__dso_handle); 295#endif 296 297#ifdef FINI_ARRAY_SECTION_ASM_OP 298 /* If we are using .fini_array then destructors will be run via that 299 mechanism. */ 300#elif defined(HIDDEN_DTOR_LIST_END) 301 { 302 /* Safer version that makes sure only .dtors function pointers are 303 called even if the static variable is maliciously changed. */ 304 extern func_ptr __DTOR_END__[] __attribute__((visibility ("hidden"))); 305 static size_t dtor_idx; 306 const size_t max_idx = __DTOR_END__ - __DTOR_LIST__ - 1; 307 func_ptr f; 308 309 while (dtor_idx < max_idx) 310 { 311 f = __DTOR_LIST__[++dtor_idx]; 312 f (); 313 } 314 } 315#else /* !defined (FINI_ARRAY_SECTION_ASM_OP) */ 316 { 317 static func_ptr *p = __DTOR_LIST__ + 1; 318 func_ptr f; 319 320 while ((f = *p)) 321 { 322 p++; 323 f (); 324 } 325 } 326#endif /* !defined(FINI_ARRAY_SECTION_ASM_OP) */ 327 328#ifdef USE_EH_FRAME_REGISTRY 329#ifdef CRT_GET_RFIB_DATA 330 /* If we used the new __register_frame_info_bases interface, 331 make sure that we deregister from the same place. */ 332 if (__deregister_frame_info_bases) 333 __deregister_frame_info_bases (__EH_FRAME_BEGIN__); 334#else 335 if (__deregister_frame_info) 336 __deregister_frame_info (__EH_FRAME_BEGIN__); 337#endif 338#endif 339 340 completed = 1; 341} 342 343/* Stick a call to __do_global_dtors_aux into the .fini section. */ 344#ifdef FINI_SECTION_ASM_OP 345CRT_CALL_STATIC_FUNCTION (FINI_SECTION_ASM_OP, __do_global_dtors_aux) 346#elif defined (FINI_ARRAY_SECTION_ASM_OP) 347static func_ptr __do_global_dtors_aux_fini_array_entry[] 348 __attribute__ ((__unused__, section(".fini_array"))) 349 = { __do_global_dtors_aux }; 350#else /* !FINI_SECTION_ASM_OP && !FINI_ARRAY_SECTION_ASM_OP */ 351static void __attribute__((used)) 352__do_global_dtors_aux_1 (void) 353{ 354 atexit (__do_global_dtors_aux); 355} 356CRT_CALL_STATIC_FUNCTION (INIT_SECTION_ASM_OP, __do_global_dtors_aux_1) 357#endif 358 359#if defined(USE_EH_FRAME_REGISTRY) || defined(JCR_SECTION_NAME) 360/* Stick a call to __register_frame_info into the .init section. For some 361 reason calls with no arguments work more reliably in .init, so stick the 362 call in another function. */ 363 364static void __attribute__((used)) 365frame_dummy (void) 366{ 367#ifdef USE_EH_FRAME_REGISTRY 368 static struct object object; 369#ifdef CRT_GET_RFIB_DATA 370 void *tbase, *dbase; 371 tbase = 0; 372 CRT_GET_RFIB_DATA (dbase); 373 if (__register_frame_info_bases) 374 __register_frame_info_bases (__EH_FRAME_BEGIN__, &object, tbase, dbase); 375#else 376 if (__register_frame_info) 377 __register_frame_info (__EH_FRAME_BEGIN__, &object); 378#endif /* CRT_GET_RFIB_DATA */ 379#endif /* USE_EH_FRAME_REGISTRY */ 380#ifdef JCR_SECTION_NAME 381 if (__JCR_LIST__[0]) 382 { 383 void (*register_classes) (void *) = _Jv_RegisterClasses; 384 __asm ("" : "+r" (register_classes)); 385 if (register_classes) 386 register_classes (__JCR_LIST__); 387 } 388#endif /* JCR_SECTION_NAME */ 389} 390 391#ifdef INIT_SECTION_ASM_OP 392CRT_CALL_STATIC_FUNCTION (INIT_SECTION_ASM_OP, frame_dummy) 393#else /* defined(INIT_SECTION_ASM_OP) */ 394static func_ptr __frame_dummy_init_array_entry[] 395 __attribute__ ((__unused__, section(".init_array"))) 396 = { frame_dummy }; 397#endif /* !defined(INIT_SECTION_ASM_OP) */ 398#endif /* USE_EH_FRAME_REGISTRY || JCR_SECTION_NAME */ 399 400#else /* OBJECT_FORMAT_ELF */ 401 402/* The function __do_global_ctors_aux is compiled twice (once in crtbegin.o 403 and once in crtend.o). It must be declared static to avoid a link 404 error. Here, we define __do_global_ctors as an externally callable 405 function. It is externally callable so that __main can invoke it when 406 INVOKE__main is defined. This has the additional effect of forcing cc1 407 to switch to the .text section. */ 408 409static void __do_global_ctors_aux (void); 410void 411__do_global_ctors (void) 412{ 413#ifdef INVOKE__main 414 /* If __main won't actually call __do_global_ctors then it doesn't matter 415 what's inside the function. The inside of __do_global_ctors_aux is 416 called automatically in that case. And the Alliant fx2800 linker 417 crashes on this reference. So prevent the crash. */ 418 __do_global_ctors_aux (); 419#endif 420} 421 422asm (INIT_SECTION_ASM_OP); /* cc1 doesn't know that we are switching! */ 423 424/* A routine to invoke all of the global constructors upon entry to the 425 program. We put this into the .init section (for systems that have 426 such a thing) so that we can properly perform the construction of 427 file-scope static-storage C++ objects within shared libraries. */ 428 429static void __attribute__((used)) 430__do_global_ctors_aux (void) /* prologue goes in .init section */ 431{ 432 FORCE_CODE_SECTION_ALIGN /* explicit align before switch to .text */ 433 asm (TEXT_SECTION_ASM_OP); /* don't put epilogue and body in .init */ 434 DO_GLOBAL_CTORS_BODY; 435 atexit (__do_global_dtors); 436} 437 438#endif /* OBJECT_FORMAT_ELF */ 439 440#elif defined(HAS_INIT_SECTION) /* ! INIT_SECTION_ASM_OP */ 441 442extern void __do_global_dtors (void); 443 444/* This case is used by the Irix 6 port, which supports named sections but 445 not an SVR4-style .fini section. __do_global_dtors can be non-static 446 in this case because we protect it with -hidden_symbol. */ 447 448void 449__do_global_dtors (void) 450{ 451 func_ptr *p, f; 452 for (p = __DTOR_LIST__ + 1; (f = *p); p++) 453 f (); 454 455#ifdef USE_EH_FRAME_REGISTRY 456 if (__deregister_frame_info) 457 __deregister_frame_info (__EH_FRAME_BEGIN__); 458#endif 459} 460 461#if defined(USE_EH_FRAME_REGISTRY) || defined(JCR_SECTION_NAME) 462/* A helper function for __do_global_ctors, which is in crtend.o. Here 463 in crtbegin.o, we can reference a couple of symbols not visible there. 464 Plus, since we're before libgcc.a, we have no problems referencing 465 functions from there. */ 466void 467__do_global_ctors_1(void) 468{ 469#ifdef USE_EH_FRAME_REGISTRY 470 static struct object object; 471 if (__register_frame_info) 472 __register_frame_info (__EH_FRAME_BEGIN__, &object); 473#endif 474#ifdef JCR_SECTION_NAME 475 if (__JCR_LIST__[0]) 476 { 477 void (*register_classes) (void *) = _Jv_RegisterClasses; 478 __asm ("" : "+r" (register_classes)); 479 if (register_classes) 480 register_classes (__JCR_LIST__); 481 } 482#endif 483} 484#endif /* USE_EH_FRAME_REGISTRY || JCR_SECTION_NAME */ 485 486#else /* ! INIT_SECTION_ASM_OP && ! HAS_INIT_SECTION */ 487#error "What are you doing with crtstuff.c, then?" 488#endif 489 490#elif defined(CRT_END) /* ! CRT_BEGIN */ 491 492/* Put a word containing zero at the end of each of our two lists of function 493 addresses. Note that the words defined here go into the .ctors and .dtors 494 sections of the crtend.o file, and since that file is always linked in 495 last, these words naturally end up at the very ends of the two lists 496 contained in these two sections. */ 497 498#ifdef CTOR_LIST_END 499CTOR_LIST_END; 500#elif defined(CTORS_SECTION_ASM_OP) 501/* Hack: force cc1 to switch to .data section early, so that assembling 502 __CTOR_LIST__ does not undo our behind-the-back change to .ctors. */ 503static func_ptr force_to_data[1] __attribute__ ((__unused__)) = { }; 504asm (CTORS_SECTION_ASM_OP); 505STATIC func_ptr __CTOR_END__[1] 506 __attribute__((aligned(sizeof(func_ptr)))) 507 = { (func_ptr) 0 }; 508#else 509STATIC func_ptr __CTOR_END__[1] 510 __attribute__((section(".ctors"), aligned(sizeof(func_ptr)))) 511 = { (func_ptr) 0 }; 512#endif 513 514#ifdef DTOR_LIST_END 515DTOR_LIST_END; 516#elif defined(HIDDEN_DTOR_LIST_END) 517#ifdef DTORS_SECTION_ASM_OP 518asm (DTORS_SECTION_ASM_OP); 519#endif 520func_ptr __DTOR_END__[1] 521 __attribute__ ((unused, 522#ifndef DTORS_SECTION_ASM_OP 523 section(".dtors"), 524#endif 525 aligned(sizeof(func_ptr)), visibility ("hidden"))) 526 = { (func_ptr) 0 }; 527#elif defined(DTORS_SECTION_ASM_OP) 528asm (DTORS_SECTION_ASM_OP); 529STATIC func_ptr __DTOR_END__[1] 530 __attribute__ ((unused, aligned(sizeof(func_ptr)))) 531 = { (func_ptr) 0 }; 532#else 533STATIC func_ptr __DTOR_END__[1] 534 __attribute__((unused, section(".dtors"), aligned(sizeof(func_ptr)))) 535 = { (func_ptr) 0 }; 536#endif 537 538#ifdef EH_FRAME_SECTION_NAME 539/* Terminate the frame unwind info section with a 4byte 0 as a sentinel; 540 this would be the 'length' field in a real FDE. */ 541# if __INT_MAX__ == 2147483647 542typedef int int32; 543# elif __LONG_MAX__ == 2147483647 544typedef long int32; 545# elif __SHRT_MAX__ == 2147483647 546typedef short int32; 547# else 548# error "Missing a 4 byte integer" 549# endif 550STATIC EH_FRAME_SECTION_CONST int32 __FRAME_END__[] 551 __attribute__ ((unused, section(EH_FRAME_SECTION_NAME), 552 aligned(sizeof(int32)))) 553 = { 0 }; 554#endif /* EH_FRAME_SECTION_NAME */ 555 556#ifdef JCR_SECTION_NAME 557/* Null terminate the .jcr section array. */ 558STATIC void *__JCR_END__[1] 559 __attribute__ ((unused, section(JCR_SECTION_NAME), 560 aligned(sizeof(void *)))) 561 = { 0 }; 562#endif /* JCR_SECTION_NAME */ 563 564#ifdef INIT_ARRAY_SECTION_ASM_OP 565 566/* If we are using .init_array, there is nothing to do. */ 567 568#elif defined(INIT_SECTION_ASM_OP) 569 570#ifdef OBJECT_FORMAT_ELF 571static void __attribute__((used)) 572__do_global_ctors_aux (void) 573{ 574 func_ptr *p; 575 for (p = __CTOR_END__ - 1; *p != (func_ptr) -1; p--) 576 (*p) (); 577} 578 579/* Stick a call to __do_global_ctors_aux into the .init section. */ 580CRT_CALL_STATIC_FUNCTION (INIT_SECTION_ASM_OP, __do_global_ctors_aux) 581#else /* OBJECT_FORMAT_ELF */ 582 583/* Stick the real initialization code, followed by a normal sort of 584 function epilogue at the very end of the .init section for this 585 entire root executable file or for this entire shared library file. 586 587 Note that we use some tricks here to get *just* the body and just 588 a function epilogue (but no function prologue) into the .init 589 section of the crtend.o file. Specifically, we switch to the .text 590 section, start to define a function, and then we switch to the .init 591 section just before the body code. 592 593 Earlier on, we put the corresponding function prologue into the .init 594 section of the crtbegin.o file (which will be linked in first). 595 596 Note that we want to invoke all constructors for C++ file-scope static- 597 storage objects AFTER any other possible initialization actions which 598 may be performed by the code in the .init section contributions made by 599 other libraries, etc. That's because those other initializations may 600 include setup operations for very primitive things (e.g. initializing 601 the state of the floating-point coprocessor, etc.) which should be done 602 before we start to execute any of the user's code. */ 603 604static void 605__do_global_ctors_aux (void) /* prologue goes in .text section */ 606{ 607 asm (INIT_SECTION_ASM_OP); 608 DO_GLOBAL_CTORS_BODY; 609 atexit (__do_global_dtors); 610} /* epilogue and body go in .init section */ 611 612FORCE_CODE_SECTION_ALIGN 613asm (TEXT_SECTION_ASM_OP); 614 615#endif /* OBJECT_FORMAT_ELF */ 616 617#elif defined(HAS_INIT_SECTION) /* ! INIT_SECTION_ASM_OP */ 618 619extern void __do_global_ctors (void); 620 621/* This case is used by the Irix 6 port, which supports named sections but 622 not an SVR4-style .init section. __do_global_ctors can be non-static 623 in this case because we protect it with -hidden_symbol. */ 624void 625__do_global_ctors (void) 626{ 627 func_ptr *p; 628#if defined(USE_EH_FRAME_REGISTRY) || defined(JCR_SECTION_NAME) 629 __do_global_ctors_1(); 630#endif 631 for (p = __CTOR_END__ - 1; *p != (func_ptr) -1; p--) 632 (*p) (); 633} 634 635#else /* ! INIT_SECTION_ASM_OP && ! HAS_INIT_SECTION */ 636#error "What are you doing with crtstuff.c, then?" 637#endif 638 639#else /* ! CRT_BEGIN && ! CRT_END */ 640#error "One of CRT_BEGIN or CRT_END must be defined." 641#endif 642