1 /* Specialized bits of code needed to support construction and 2 destruction of file-scope objects in C++ code. 3 Copyright (C) 1991-2020 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__) || defined(__NetBSD__)) 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 #elif !defined(USE_TM_CLONE_REGISTRY) 157 # define USE_TM_CLONE_REGISTRY 0 158 #endif 159 160 /* We do not want to add the weak attribute to the declarations of these 161 routines in unwind-dw2-fde.h because that will cause the definition of 162 these symbols to be weak as well. 163 164 This exposes a core issue, how to handle creating weak references vs 165 how to create weak definitions. Either we have to have the definition 166 of TARGET_WEAK_ATTRIBUTE be conditional in the shared header files or 167 have a second declaration if we want a function's references to be weak, 168 but not its definition. 169 170 Making TARGET_WEAK_ATTRIBUTE conditional seems like a good solution until 171 one thinks about scaling to larger problems -- i.e., the condition under 172 which TARGET_WEAK_ATTRIBUTE is active will eventually get far too 173 complicated. 174 175 So, we take an approach similar to #pragma weak -- we have a second 176 declaration for functions that we want to have weak references. 177 178 Neither way is particularly good. */ 179 180 /* References to __register_frame_info and __deregister_frame_info should 181 be weak in this file if at all possible. */ 182 extern void __register_frame_info (const void *, struct object *) 183 TARGET_ATTRIBUTE_WEAK; 184 extern void __register_frame_info_bases (const void *, struct object *, 185 void *, void *) 186 TARGET_ATTRIBUTE_WEAK; 187 extern void *__deregister_frame_info (const void *) 188 TARGET_ATTRIBUTE_WEAK; 189 extern void *__deregister_frame_info_bases (const void *) 190 TARGET_ATTRIBUTE_WEAK; 191 extern void __do_global_ctors_1 (void); 192 193 /* Likewise for transactional memory clone tables. */ 194 extern void _ITM_registerTMCloneTable (void *, size_t) TARGET_ATTRIBUTE_WEAK; 195 extern void _ITM_deregisterTMCloneTable (void *) TARGET_ATTRIBUTE_WEAK; 196 197 #ifdef OBJECT_FORMAT_ELF 198 199 /* Declare a pointer to void function type. */ 200 typedef void (*func_ptr) (void); 201 #define STATIC static 202 203 #else /* OBJECT_FORMAT_ELF */ 204 205 #include "gbl-ctors.h" 206 207 #define STATIC 208 209 #endif /* OBJECT_FORMAT_ELF */ 210 211 #ifdef CRT_BEGIN 212 213 /* NOTE: In order to be able to support SVR4 shared libraries, we arrange 214 to have one set of symbols { __CTOR_LIST__, __DTOR_LIST__, __CTOR_END__, 215 __DTOR_END__ } per root executable and also one set of these symbols 216 per shared library. So in any given whole process image, we may have 217 multiple definitions of each of these symbols. In order to prevent 218 these definitions from conflicting with one another, and in order to 219 ensure that the proper lists are used for the initialization/finalization 220 of each individual shared library (respectively), we give these symbols 221 only internal (i.e. `static') linkage, and we also make it a point to 222 refer to only the __CTOR_END__ symbol in crtend.o and the __DTOR_LIST__ 223 symbol in crtbegin.o, where they are defined. */ 224 225 /* No need for .ctors/.dtors section if linker can place them in 226 .init_array/.fini_array section. */ 227 #ifndef USE_INITFINI_ARRAY 228 /* The -1 is a flag to __do_global_[cd]tors indicating that this table 229 does not start with a count of elements. */ 230 #ifdef CTOR_LIST_BEGIN 231 CTOR_LIST_BEGIN; 232 #elif defined(__LIBGCC_CTORS_SECTION_ASM_OP__) 233 /* Hack: force cc1 to switch to .data section early, so that assembling 234 __CTOR_LIST__ does not undo our behind-the-back change to .ctors. */ 235 static func_ptr force_to_data[1] __attribute__ ((__used__)) = { }; 236 asm (__LIBGCC_CTORS_SECTION_ASM_OP__); 237 STATIC func_ptr __CTOR_LIST__[1] 238 __attribute__ ((__used__, aligned(__alignof__(func_ptr)))) 239 = { (func_ptr) (-1) }; 240 #else 241 STATIC func_ptr __CTOR_LIST__[1] 242 __attribute__ ((__used__, section(".ctors"), aligned(__alignof__(func_ptr)))) 243 = { (func_ptr) (-1) }; 244 #endif /* __CTOR_LIST__ alternatives */ 245 246 #ifdef DTOR_LIST_BEGIN 247 DTOR_LIST_BEGIN; 248 #elif defined(__LIBGCC_DTORS_SECTION_ASM_OP__) 249 asm (__LIBGCC_DTORS_SECTION_ASM_OP__); 250 STATIC func_ptr __DTOR_LIST__[1] 251 __attribute__ ((aligned(__alignof__(func_ptr)))) 252 = { (func_ptr) (-1) }; 253 #else 254 STATIC func_ptr __DTOR_LIST__[1] 255 __attribute__((section(".dtors"), aligned(__alignof__(func_ptr)))) 256 = { (func_ptr) (-1) }; 257 #endif /* __DTOR_LIST__ alternatives */ 258 #endif /* USE_INITFINI_ARRAY */ 259 260 #ifdef USE_EH_FRAME_REGISTRY 261 /* Stick a label at the beginning of the frame unwind info so we can register 262 and deregister it with the exception handling library code. */ 263 STATIC EH_FRAME_SECTION_CONST char __EH_FRAME_BEGIN__[] 264 __attribute__((section(__LIBGCC_EH_FRAME_SECTION_NAME__), aligned(4))) 265 = { }; 266 #endif /* USE_EH_FRAME_REGISTRY */ 267 268 #if USE_TM_CLONE_REGISTRY 269 STATIC func_ptr __TMC_LIST__[] 270 __attribute__((used, section(".tm_clone_table"), aligned(__alignof__(void*)))) 271 = { }; 272 # ifdef HAVE_GAS_HIDDEN 273 extern func_ptr __TMC_END__[] __attribute__((__visibility__ ("hidden"))); 274 # endif 275 276 static inline void 277 deregister_tm_clones (void) 278 { 279 void (*fn) (void *); 280 281 #ifdef HAVE_GAS_HIDDEN 282 func_ptr *end = __TMC_END__; 283 // Do not optimize the comparison to false. 284 __asm ("" : "+g" (end)); 285 if (__TMC_LIST__ == end) 286 return; 287 #else 288 if (__TMC_LIST__[0] == NULL) 289 return; 290 #endif 291 292 fn = _ITM_deregisterTMCloneTable; 293 __asm ("" : "+r" (fn)); 294 if (fn) 295 fn (__TMC_LIST__); 296 } 297 298 static inline void 299 register_tm_clones (void) 300 { 301 void (*fn) (void *, size_t); 302 size_t size; 303 304 #ifdef HAVE_GAS_HIDDEN 305 func_ptr *end = __TMC_END__; 306 // Do not optimize the comparison to false. 307 __asm ("" : "+g" (end)); 308 size = (end - __TMC_LIST__) / 2; 309 #else 310 for (size = 0; __TMC_LIST__[size * 2] != NULL; size++) 311 continue; 312 #endif 313 if (size == 0) 314 return; 315 316 fn = _ITM_registerTMCloneTable; 317 __asm ("" : "+r" (fn)); 318 if (fn) 319 fn (__TMC_LIST__, size); 320 } 321 #endif /* USE_TM_CLONE_REGISTRY */ 322 323 #if defined(__LIBGCC_INIT_SECTION_ASM_OP__) \ 324 || defined(__LIBGCC_INIT_ARRAY_SECTION_ASM_OP__) 325 326 #ifdef OBJECT_FORMAT_ELF 327 328 #if DEFAULT_USE_CXA_ATEXIT 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 If __cxa_atexit is not being used, __dso_handle will not be used and 335 doesn't need to be defined. */ 336 337 #ifdef TARGET_LIBGCC_SDATA_SECTION 338 extern void *__dso_handle __attribute__ ((__section__ (TARGET_LIBGCC_SDATA_SECTION))); 339 #endif 340 #ifdef HAVE_GAS_HIDDEN 341 extern void *__dso_handle __attribute__ ((__visibility__ ("hidden"))); 342 #endif 343 #ifdef CRTSTUFFS_O 344 void *__dso_handle = &__dso_handle; 345 #else 346 void *__dso_handle = 0; 347 #endif 348 #endif /* DEFAULT_USE_CXA_ATEXIT */ 349 350 /* The __cxa_finalize function may not be available so we use only a 351 weak declaration. */ 352 extern void __cxa_finalize (void *) TARGET_ATTRIBUTE_WEAK; 353 354 /* Run all the global destructors on exit from the program. */ 355 356 /* Some systems place the number of pointers in the first word of the 357 table. On SVR4 however, that word is -1. In all cases, the table is 358 null-terminated. On SVR4, we start from the beginning of the list and 359 invoke each per-compilation-unit destructor routine in order 360 until we find that null. 361 362 Note that this function MUST be static. There will be one of these 363 functions in each root executable and one in each shared library, but 364 although they all have the same code, each one is unique in that it 365 refers to one particular associated `__DTOR_LIST__' which belongs to the 366 same particular root executable or shared library file. 367 368 On some systems, this routine is run more than once from the .fini, 369 when exit is called recursively, so we arrange to remember where in 370 the list we left off processing, and we resume at that point, 371 should we be re-invoked. 372 373 This routine does not need to be run if none of the following clauses are 374 true, as it will not do anything, so can be removed. */ 375 #if defined(CRTSTUFFS_O) || !defined(FINI_ARRAY_SECTION_ASM_OP) \ 376 || USE_TM_CLONE_REGISTRY || defined(USE_EH_FRAME_REGISTRY) 377 static void __attribute__((used)) 378 __do_global_dtors_aux (void) 379 { 380 static _Bool completed; 381 382 if (__builtin_expect (completed, 0)) 383 return; 384 385 #if DEFAULT_USE_CXA_ATEXIT 386 #ifdef CRTSTUFFS_O 387 if (__cxa_finalize) 388 __cxa_finalize (__dso_handle); 389 #endif 390 #endif 391 392 #ifdef FINI_ARRAY_SECTION_ASM_OP 393 /* If we are using .fini_array then destructors will be run via that 394 mechanism. */ 395 #elif defined(HIDDEN_DTOR_LIST_END) 396 { 397 /* Safer version that makes sure only .dtors function pointers are 398 called even if the static variable is maliciously changed. */ 399 extern func_ptr __DTOR_END__[] __attribute__((visibility ("hidden"))); 400 static size_t dtor_idx; 401 const size_t max_idx = __DTOR_END__ - __DTOR_LIST__ - 1; 402 func_ptr *dtor_list; 403 404 __asm ("" : "=g" (dtor_list) : "0" (__DTOR_LIST__)); 405 while (dtor_idx < max_idx) 406 dtor_list[++dtor_idx] (); 407 } 408 #else /* !defined (FINI_ARRAY_SECTION_ASM_OP) */ 409 { 410 static func_ptr *p = __DTOR_LIST__ + 1; 411 func_ptr f; 412 413 while ((f = *p)) 414 { 415 p++; 416 f (); 417 } 418 } 419 #endif /* !defined(FINI_ARRAY_SECTION_ASM_OP) */ 420 421 #if USE_TM_CLONE_REGISTRY 422 deregister_tm_clones (); 423 #endif /* USE_TM_CLONE_REGISTRY */ 424 425 #ifdef USE_EH_FRAME_REGISTRY 426 #ifdef CRT_GET_RFIB_DATA 427 /* If we used the new __register_frame_info_bases interface, 428 make sure that we deregister from the same place. */ 429 if (__deregister_frame_info_bases) 430 __deregister_frame_info_bases (__EH_FRAME_BEGIN__); 431 #else 432 if (__deregister_frame_info) 433 __deregister_frame_info (__EH_FRAME_BEGIN__); 434 #endif 435 #endif 436 437 completed = 1; 438 } 439 440 /* Stick a call to __do_global_dtors_aux into the .fini section. */ 441 #ifdef FINI_SECTION_ASM_OP 442 CRT_CALL_STATIC_FUNCTION (FINI_SECTION_ASM_OP, __do_global_dtors_aux) 443 #elif defined (FINI_ARRAY_SECTION_ASM_OP) 444 #if defined(__FDPIC__) 445 __asm__("\t.equ\t__do_global_dtors_aux_alias, __do_global_dtors_aux\n"); 446 extern char __do_global_dtors_aux_alias; 447 static void *__do_global_dtors_aux_fini_array_entry[] 448 __attribute__ ((__used__, section(".fini_array"), aligned(sizeof(void *)))) 449 = { &__do_global_dtors_aux_alias }; 450 #else /* defined(__FDPIC__) */ 451 static func_ptr __do_global_dtors_aux_fini_array_entry[] 452 __attribute__ ((__used__, section(".fini_array"), 453 aligned(__alignof__(func_ptr)))) = { __do_global_dtors_aux }; 454 #endif /* defined(__FDPIC__) */ 455 #else /* !FINI_SECTION_ASM_OP && !FINI_ARRAY_SECTION_ASM_OP */ 456 static void __attribute__((used)) 457 __do_global_dtors_aux_1 (void) 458 { 459 atexit (__do_global_dtors_aux); 460 } 461 CRT_CALL_STATIC_FUNCTION (__LIBGCC_INIT_SECTION_ASM_OP__, 462 __do_global_dtors_aux_1) 463 #endif 464 #endif /* defined(CRTSTUFFS_O) || !defined(FINI_ARRAY_SECTION_ASM_OP) 465 || USE_TM_CLONE_REGISTRY || defined(USE_EH_FRAME_REGISTRY) */ 466 467 #if defined(USE_EH_FRAME_REGISTRY) || USE_TM_CLONE_REGISTRY 468 /* Stick a call to __register_frame_info into the .init section. For some 469 reason calls with no arguments work more reliably in .init, so stick the 470 call in another function. */ 471 472 static void __attribute__((used)) 473 frame_dummy (void) 474 { 475 #ifdef USE_EH_FRAME_REGISTRY 476 static struct object object; 477 #ifdef CRT_GET_RFIB_DATA 478 void *tbase, *dbase; 479 tbase = 0; 480 CRT_GET_RFIB_DATA (dbase); 481 if (__register_frame_info_bases) 482 __register_frame_info_bases (__EH_FRAME_BEGIN__, &object, tbase, dbase); 483 #else 484 if (__register_frame_info) 485 __register_frame_info (__EH_FRAME_BEGIN__, &object); 486 #endif /* CRT_GET_RFIB_DATA */ 487 #endif /* USE_EH_FRAME_REGISTRY */ 488 489 #if USE_TM_CLONE_REGISTRY 490 register_tm_clones (); 491 #endif /* USE_TM_CLONE_REGISTRY */ 492 } 493 494 #ifdef __LIBGCC_INIT_SECTION_ASM_OP__ 495 CRT_CALL_STATIC_FUNCTION (__LIBGCC_INIT_SECTION_ASM_OP__, frame_dummy) 496 #else /* defined(__LIBGCC_INIT_SECTION_ASM_OP__) */ 497 #if defined(__FDPIC__) 498 __asm__("\t.equ\t__frame_dummy_alias, frame_dummy\n"); 499 extern char __frame_dummy_alias; 500 static void *__frame_dummy_init_array_entry[] 501 __attribute__ ((__used__, section(".init_array"), aligned(sizeof(void *)))) 502 = { &__frame_dummy_alias }; 503 #else /* defined(__FDPIC__) */ 504 static func_ptr __frame_dummy_init_array_entry[] 505 __attribute__ ((__used__, section(".init_array"), 506 aligned(__alignof__(func_ptr)))) = { frame_dummy }; 507 #endif /* defined(__FDPIC__) */ 508 #endif /* !defined(__LIBGCC_INIT_SECTION_ASM_OP__) */ 509 #endif /* USE_EH_FRAME_REGISTRY || USE_TM_CLONE_REGISTRY */ 510 511 #else /* OBJECT_FORMAT_ELF */ 512 513 /* The function __do_global_ctors_aux is compiled twice (once in crtbegin.o 514 and once in crtend.o). It must be declared static to avoid a link 515 error. Here, we define __do_global_ctors as an externally callable 516 function. It is externally callable so that __main can invoke it when 517 INVOKE__main is defined. This has the additional effect of forcing cc1 518 to switch to the .text section. */ 519 520 static void __do_global_ctors_aux (void); 521 void 522 __do_global_ctors (void) 523 { 524 #ifdef INVOKE__main 525 /* If __main won't actually call __do_global_ctors then it doesn't matter 526 what's inside the function. The inside of __do_global_ctors_aux is 527 called automatically in that case. And the Alliant fx2800 linker 528 crashes on this reference. So prevent the crash. */ 529 __do_global_ctors_aux (); 530 #endif 531 } 532 533 asm (__LIBGCC_INIT_SECTION_ASM_OP__); /* cc1 doesn't know that we are switching! */ 534 535 /* A routine to invoke all of the global constructors upon entry to the 536 program. We put this into the .init section (for systems that have 537 such a thing) so that we can properly perform the construction of 538 file-scope static-storage C++ objects within shared libraries. */ 539 540 static void __attribute__((used)) 541 __do_global_ctors_aux (void) /* prologue goes in .init section */ 542 { 543 FORCE_CODE_SECTION_ALIGN /* explicit align before switch to .text */ 544 asm (__LIBGCC_TEXT_SECTION_ASM_OP__); /* don't put epilogue and body in .init */ 545 DO_GLOBAL_CTORS_BODY; 546 atexit (__do_global_dtors); 547 } 548 549 #endif /* OBJECT_FORMAT_ELF */ 550 551 #elif defined(HAS_INIT_SECTION) /* ! __LIBGCC_INIT_SECTION_ASM_OP__ */ 552 553 extern void __do_global_dtors (void); 554 555 /* This case is used by the Irix 6 port, which supports named sections but 556 not an SVR4-style .fini section. __do_global_dtors can be non-static 557 in this case because we protect it with -hidden_symbol. */ 558 559 void 560 __do_global_dtors (void) 561 { 562 func_ptr *p, f; 563 for (p = __DTOR_LIST__ + 1; (f = *p); p++) 564 f (); 565 566 #if USE_TM_CLONE_REGISTRY 567 deregister_tm_clones (); 568 #endif /* USE_TM_CLONE_REGISTRY */ 569 570 #ifdef USE_EH_FRAME_REGISTRY 571 if (__deregister_frame_info) 572 __deregister_frame_info (__EH_FRAME_BEGIN__); 573 #endif 574 } 575 576 #if defined(USE_EH_FRAME_REGISTRY) || USE_TM_CLONE_REGISTRY 577 /* A helper function for __do_global_ctors, which is in crtend.o. Here 578 in crtbegin.o, we can reference a couple of symbols not visible there. 579 Plus, since we're before libgcc.a, we have no problems referencing 580 functions from there. */ 581 void 582 __do_global_ctors_1(void) 583 { 584 #ifdef USE_EH_FRAME_REGISTRY 585 static struct object object; 586 if (__register_frame_info) 587 __register_frame_info (__EH_FRAME_BEGIN__, &object); 588 #endif 589 590 #if USE_TM_CLONE_REGISTRY 591 register_tm_clones (); 592 #endif /* USE_TM_CLONE_REGISTRY */ 593 } 594 #endif /* USE_EH_FRAME_REGISTRY || USE_TM_CLONE_REGISTRY */ 595 596 #else /* ! __LIBGCC_INIT_SECTION_ASM_OP__ && ! HAS_INIT_SECTION */ 597 #error "What are you doing with crtstuff.c, then?" 598 #endif 599 600 #elif defined(CRT_END) /* ! CRT_BEGIN */ 601 602 /* No need for .ctors/.dtors section if linker can place them in 603 .init_array/.fini_array section. */ 604 #ifndef USE_INITFINI_ARRAY 605 /* Put a word containing zero at the end of each of our two lists of function 606 addresses. Note that the words defined here go into the .ctors and .dtors 607 sections of the crtend.o file, and since that file is always linked in 608 last, these words naturally end up at the very ends of the two lists 609 contained in these two sections. */ 610 611 #ifdef CTOR_LIST_END 612 CTOR_LIST_END; 613 #elif defined(__LIBGCC_CTORS_SECTION_ASM_OP__) 614 /* Hack: force cc1 to switch to .data section early, so that assembling 615 __CTOR_LIST__ does not undo our behind-the-back change to .ctors. */ 616 static func_ptr force_to_data[1] __attribute__ ((__used__)) = { }; 617 asm (__LIBGCC_CTORS_SECTION_ASM_OP__); 618 STATIC func_ptr __CTOR_END__[1] 619 __attribute__((aligned(__alignof__(func_ptr)))) 620 = { (func_ptr) 0 }; 621 #else 622 STATIC func_ptr __CTOR_END__[1] 623 __attribute__((section(".ctors"), aligned(__alignof__(func_ptr)))) 624 = { (func_ptr) 0 }; 625 #endif 626 627 #ifdef DTOR_LIST_END 628 DTOR_LIST_END; 629 #elif defined(HIDDEN_DTOR_LIST_END) 630 #ifdef __LIBGCC_DTORS_SECTION_ASM_OP__ 631 asm (__LIBGCC_DTORS_SECTION_ASM_OP__); 632 #endif 633 func_ptr __DTOR_END__[1] 634 __attribute__ ((used, 635 #ifndef __LIBGCC_DTORS_SECTION_ASM_OP__ 636 section(".dtors"), 637 #endif 638 aligned(__alignof__(func_ptr)), visibility ("hidden"))) 639 = { (func_ptr) 0 }; 640 #elif defined(__LIBGCC_DTORS_SECTION_ASM_OP__) 641 asm (__LIBGCC_DTORS_SECTION_ASM_OP__); 642 STATIC func_ptr __DTOR_END__[1] 643 __attribute__ ((used, aligned(__alignof__(func_ptr)))) 644 = { (func_ptr) 0 }; 645 #else 646 STATIC func_ptr __DTOR_END__[1] 647 __attribute__((used, section(".dtors"), aligned(__alignof__(func_ptr)))) 648 = { (func_ptr) 0 }; 649 #endif 650 #endif /* USE_INITFINI_ARRAY */ 651 652 #ifdef __LIBGCC_EH_FRAME_SECTION_NAME__ 653 /* Terminate the frame unwind info section with a 4byte 0 as a sentinel; 654 this would be the 'length' field in a real FDE. */ 655 # if __INT_MAX__ == 2147483647 656 typedef int int32; 657 # elif __LONG_MAX__ == 2147483647 658 typedef long int32; 659 # elif __SHRT_MAX__ == 2147483647 660 typedef short int32; 661 # else 662 # error "Missing a 4 byte integer" 663 # endif 664 STATIC EH_FRAME_SECTION_CONST int32 __FRAME_END__[] 665 __attribute__ ((used, section(__LIBGCC_EH_FRAME_SECTION_NAME__), 666 aligned(__alignof__(int32)))) 667 = { 0 }; 668 #endif /* __LIBGCC_EH_FRAME_SECTION_NAME__ */ 669 670 #if USE_TM_CLONE_REGISTRY 671 # ifndef HAVE_GAS_HIDDEN 672 static 673 # endif 674 func_ptr __TMC_END__[] 675 __attribute__((used, section(".tm_clone_table"), 676 aligned(__alignof__(void *)))) 677 # ifdef HAVE_GAS_HIDDEN 678 __attribute__((__visibility__ ("hidden"))) = { }; 679 # else 680 = { 0, 0 }; 681 # endif 682 #endif /* USE_TM_CLONE_REGISTRY */ 683 684 #ifdef __LIBGCC_INIT_ARRAY_SECTION_ASM_OP__ 685 686 /* If we are using .init_array, there is nothing to do. */ 687 688 #elif defined(__LIBGCC_INIT_SECTION_ASM_OP__) 689 690 #ifdef OBJECT_FORMAT_ELF 691 static void __attribute__((used)) 692 __do_global_ctors_aux (void) 693 { 694 func_ptr *p; 695 for (p = __CTOR_END__ - 1; *p != (func_ptr) -1; p--) 696 (*p) (); 697 } 698 699 /* Stick a call to __do_global_ctors_aux into the .init section. */ 700 CRT_CALL_STATIC_FUNCTION (__LIBGCC_INIT_SECTION_ASM_OP__, __do_global_ctors_aux) 701 #else /* OBJECT_FORMAT_ELF */ 702 703 /* Stick the real initialization code, followed by a normal sort of 704 function epilogue at the very end of the .init section for this 705 entire root executable file or for this entire shared library file. 706 707 Note that we use some tricks here to get *just* the body and just 708 a function epilogue (but no function prologue) into the .init 709 section of the crtend.o file. Specifically, we switch to the .text 710 section, start to define a function, and then we switch to the .init 711 section just before the body code. 712 713 Earlier on, we put the corresponding function prologue into the .init 714 section of the crtbegin.o file (which will be linked in first). 715 716 Note that we want to invoke all constructors for C++ file-scope static- 717 storage objects AFTER any other possible initialization actions which 718 may be performed by the code in the .init section contributions made by 719 other libraries, etc. That's because those other initializations may 720 include setup operations for very primitive things (e.g. initializing 721 the state of the floating-point coprocessor, etc.) which should be done 722 before we start to execute any of the user's code. */ 723 724 static void 725 __do_global_ctors_aux (void) /* prologue goes in .text section */ 726 { 727 asm (__LIBGCC_INIT_SECTION_ASM_OP__); 728 DO_GLOBAL_CTORS_BODY; 729 atexit (__do_global_dtors); 730 } /* epilogue and body go in .init section */ 731 732 FORCE_CODE_SECTION_ALIGN 733 asm (__LIBGCC_TEXT_SECTION_ASM_OP__); 734 735 #endif /* OBJECT_FORMAT_ELF */ 736 737 #elif defined(HAS_INIT_SECTION) /* ! __LIBGCC_INIT_SECTION_ASM_OP__ */ 738 739 extern void __do_global_ctors (void); 740 741 /* This case is used by the Irix 6 port, which supports named sections but 742 not an SVR4-style .init section. __do_global_ctors can be non-static 743 in this case because we protect it with -hidden_symbol. */ 744 void 745 __do_global_ctors (void) 746 { 747 func_ptr *p; 748 #if defined(USE_EH_FRAME_REGISTRY) || USE_TM_CLONE_REGISTRY 749 __do_global_ctors_1(); 750 #endif 751 for (p = __CTOR_END__ - 1; *p != (func_ptr) -1; p--) 752 (*p) (); 753 } 754 755 #else /* ! __LIBGCC_INIT_SECTION_ASM_OP__ && ! HAS_INIT_SECTION */ 756 #error "What are you doing with crtstuff.c, then?" 757 #endif 758 759 #else /* ! CRT_BEGIN && ! CRT_END */ 760 #error "One of CRT_BEGIN or CRT_END must be defined." 761 #endif 762