1 /* Specialized bits of code needed to support construction and 2 destruction of file-scope objects in C++ code. 3 Copyright (C) 1991-2019 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 #endif 157 158 /* We do not want to add the weak attribute to the declarations of these 159 routines in unwind-dw2-fde.h because that will cause the definition of 160 these symbols to be weak as well. 161 162 This exposes a core issue, how to handle creating weak references vs 163 how to create weak definitions. Either we have to have the definition 164 of TARGET_WEAK_ATTRIBUTE be conditional in the shared header files or 165 have a second declaration if we want a function's references to be weak, 166 but not its definition. 167 168 Making TARGET_WEAK_ATTRIBUTE conditional seems like a good solution until 169 one thinks about scaling to larger problems -- i.e., the condition under 170 which TARGET_WEAK_ATTRIBUTE is active will eventually get far too 171 complicated. 172 173 So, we take an approach similar to #pragma weak -- we have a second 174 declaration for functions that we want to have weak references. 175 176 Neither way is particularly good. */ 177 178 /* References to __register_frame_info and __deregister_frame_info should 179 be weak in this file if at all possible. */ 180 extern void __register_frame_info (const void *, struct object *) 181 TARGET_ATTRIBUTE_WEAK; 182 extern void __register_frame_info_bases (const void *, struct object *, 183 void *, void *) 184 TARGET_ATTRIBUTE_WEAK; 185 extern void *__deregister_frame_info (const void *) 186 TARGET_ATTRIBUTE_WEAK; 187 extern void *__deregister_frame_info_bases (const void *) 188 TARGET_ATTRIBUTE_WEAK; 189 extern void __do_global_ctors_1 (void); 190 191 /* Likewise for transactional memory clone tables. */ 192 extern void _ITM_registerTMCloneTable (void *, size_t) TARGET_ATTRIBUTE_WEAK; 193 extern void _ITM_deregisterTMCloneTable (void *) TARGET_ATTRIBUTE_WEAK; 194 195 #ifdef OBJECT_FORMAT_ELF 196 197 /* Declare a pointer to void function type. */ 198 typedef void (*func_ptr) (void); 199 #define STATIC static 200 201 #else /* OBJECT_FORMAT_ELF */ 202 203 #include "gbl-ctors.h" 204 205 #define STATIC 206 207 #endif /* OBJECT_FORMAT_ELF */ 208 209 #ifdef CRT_BEGIN 210 211 /* NOTE: In order to be able to support SVR4 shared libraries, we arrange 212 to have one set of symbols { __CTOR_LIST__, __DTOR_LIST__, __CTOR_END__, 213 __DTOR_END__ } per root executable and also one set of these symbols 214 per shared library. So in any given whole process image, we may have 215 multiple definitions of each of these symbols. In order to prevent 216 these definitions from conflicting with one another, and in order to 217 ensure that the proper lists are used for the initialization/finalization 218 of each individual shared library (respectively), we give these symbols 219 only internal (i.e. `static') linkage, and we also make it a point to 220 refer to only the __CTOR_END__ symbol in crtend.o and the __DTOR_LIST__ 221 symbol in crtbegin.o, where they are defined. */ 222 223 /* No need for .ctors/.dtors section if linker can place them in 224 .init_array/.fini_array section. */ 225 #ifndef USE_INITFINI_ARRAY 226 /* The -1 is a flag to __do_global_[cd]tors indicating that this table 227 does not start with a count of elements. */ 228 #ifdef CTOR_LIST_BEGIN 229 CTOR_LIST_BEGIN; 230 #elif defined(__LIBGCC_CTORS_SECTION_ASM_OP__) 231 /* Hack: force cc1 to switch to .data section early, so that assembling 232 __CTOR_LIST__ does not undo our behind-the-back change to .ctors. */ 233 static func_ptr force_to_data[1] __attribute__ ((__used__)) = { }; 234 asm (__LIBGCC_CTORS_SECTION_ASM_OP__); 235 STATIC func_ptr __CTOR_LIST__[1] 236 __attribute__ ((__used__, aligned(sizeof(func_ptr)))) 237 = { (func_ptr) (-1) }; 238 #else 239 STATIC func_ptr __CTOR_LIST__[1] 240 __attribute__ ((__used__, section(".ctors"), aligned(sizeof(func_ptr)))) 241 = { (func_ptr) (-1) }; 242 #endif /* __CTOR_LIST__ alternatives */ 243 244 #ifdef DTOR_LIST_BEGIN 245 DTOR_LIST_BEGIN; 246 #elif defined(__LIBGCC_DTORS_SECTION_ASM_OP__) 247 asm (__LIBGCC_DTORS_SECTION_ASM_OP__); 248 STATIC func_ptr __DTOR_LIST__[1] 249 __attribute__ ((aligned(sizeof(func_ptr)))) 250 = { (func_ptr) (-1) }; 251 #else 252 STATIC func_ptr __DTOR_LIST__[1] 253 __attribute__((section(".dtors"), aligned(sizeof(func_ptr)))) 254 = { (func_ptr) (-1) }; 255 #endif /* __DTOR_LIST__ alternatives */ 256 #endif /* USE_INITFINI_ARRAY */ 257 258 #ifdef USE_EH_FRAME_REGISTRY 259 /* Stick a label at the beginning of the frame unwind info so we can register 260 and deregister it with the exception handling library code. */ 261 STATIC EH_FRAME_SECTION_CONST char __EH_FRAME_BEGIN__[] 262 __attribute__((section(__LIBGCC_EH_FRAME_SECTION_NAME__), aligned(4))) 263 = { }; 264 #endif /* USE_EH_FRAME_REGISTRY */ 265 266 #if USE_TM_CLONE_REGISTRY 267 STATIC func_ptr __TMC_LIST__[] 268 __attribute__((used, section(".tm_clone_table"), aligned(sizeof(void*)))) 269 = { }; 270 # ifdef HAVE_GAS_HIDDEN 271 extern func_ptr __TMC_END__[] __attribute__((__visibility__ ("hidden"))); 272 # endif 273 274 static inline void 275 deregister_tm_clones (void) 276 { 277 void (*fn) (void *); 278 279 #ifdef HAVE_GAS_HIDDEN 280 func_ptr *end = __TMC_END__; 281 // Do not optimize the comparison to false. 282 __asm ("" : "+g" (end)); 283 if (__TMC_LIST__ == end) 284 return; 285 #else 286 if (__TMC_LIST__[0] == NULL) 287 return; 288 #endif 289 290 fn = _ITM_deregisterTMCloneTable; 291 __asm ("" : "+r" (fn)); 292 if (fn) 293 fn (__TMC_LIST__); 294 } 295 296 static inline void 297 register_tm_clones (void) 298 { 299 void (*fn) (void *, size_t); 300 size_t size; 301 302 #ifdef HAVE_GAS_HIDDEN 303 func_ptr *end = __TMC_END__; 304 // Do not optimize the comparison to false. 305 __asm ("" : "+g" (end)); 306 size = (end - __TMC_LIST__) / 2; 307 #else 308 for (size = 0; __TMC_LIST__[size * 2] != NULL; size++) 309 continue; 310 #endif 311 if (size == 0) 312 return; 313 314 fn = _ITM_registerTMCloneTable; 315 __asm ("" : "+r" (fn)); 316 if (fn) 317 fn (__TMC_LIST__, size); 318 } 319 #endif /* USE_TM_CLONE_REGISTRY */ 320 321 #if defined(__LIBGCC_INIT_SECTION_ASM_OP__) \ 322 || defined(__LIBGCC_INIT_ARRAY_SECTION_ASM_OP__) 323 324 #ifdef OBJECT_FORMAT_ELF 325 326 /* Declare the __dso_handle variable. It should have a unique value 327 in every shared-object; in a main program its value is zero. The 328 object should in any case be protected. This means the instance 329 in one DSO or the main program is not used in another object. The 330 dynamic linker takes care of this. */ 331 332 #ifdef TARGET_LIBGCC_SDATA_SECTION 333 extern void *__dso_handle __attribute__ ((__section__ (TARGET_LIBGCC_SDATA_SECTION))); 334 #endif 335 #ifdef HAVE_GAS_HIDDEN 336 extern void *__dso_handle __attribute__ ((__visibility__ ("hidden"))); 337 #endif 338 #ifdef CRTSTUFFS_O 339 void *__dso_handle = &__dso_handle; 340 #else 341 void *__dso_handle = 0; 342 #endif 343 344 /* The __cxa_finalize function may not be available so we use only a 345 weak declaration. */ 346 extern void __cxa_finalize (void *) TARGET_ATTRIBUTE_WEAK; 347 348 /* Run all the global destructors on exit from the program. */ 349 350 /* Some systems place the number of pointers in the first word of the 351 table. On SVR4 however, that word is -1. In all cases, the table is 352 null-terminated. On SVR4, we start from the beginning of the list and 353 invoke each per-compilation-unit destructor routine in order 354 until we find that null. 355 356 Note that this function MUST be static. There will be one of these 357 functions in each root executable and one in each shared library, but 358 although they all have the same code, each one is unique in that it 359 refers to one particular associated `__DTOR_LIST__' which belongs to the 360 same particular root executable or shared library file. 361 362 On some systems, this routine is run more than once from the .fini, 363 when exit is called recursively, so we arrange to remember where in 364 the list we left off processing, and we resume at that point, 365 should we be re-invoked. */ 366 367 static void __attribute__((used)) 368 __do_global_dtors_aux (void) 369 { 370 static _Bool completed; 371 372 if (__builtin_expect (completed, 0)) 373 return; 374 375 #ifdef CRTSTUFFS_O 376 if (__cxa_finalize) 377 __cxa_finalize (__dso_handle); 378 #endif 379 380 #ifdef FINI_ARRAY_SECTION_ASM_OP 381 /* If we are using .fini_array then destructors will be run via that 382 mechanism. */ 383 #elif defined(HIDDEN_DTOR_LIST_END) 384 { 385 /* Safer version that makes sure only .dtors function pointers are 386 called even if the static variable is maliciously changed. */ 387 extern func_ptr __DTOR_END__[] __attribute__((visibility ("hidden"))); 388 static size_t dtor_idx; 389 const size_t max_idx = __DTOR_END__ - __DTOR_LIST__ - 1; 390 func_ptr *dtor_list; 391 392 __asm ("" : "=g" (dtor_list) : "0" (__DTOR_LIST__)); 393 while (dtor_idx < max_idx) 394 dtor_list[++dtor_idx] (); 395 } 396 #else /* !defined (FINI_ARRAY_SECTION_ASM_OP) */ 397 { 398 static func_ptr *p = __DTOR_LIST__ + 1; 399 func_ptr f; 400 401 while ((f = *p)) 402 { 403 p++; 404 f (); 405 } 406 } 407 #endif /* !defined(FINI_ARRAY_SECTION_ASM_OP) */ 408 409 #if USE_TM_CLONE_REGISTRY 410 deregister_tm_clones (); 411 #endif /* USE_TM_CLONE_REGISTRY */ 412 413 #ifdef USE_EH_FRAME_REGISTRY 414 #ifdef CRT_GET_RFIB_DATA 415 /* If we used the new __register_frame_info_bases interface, 416 make sure that we deregister from the same place. */ 417 if (__deregister_frame_info_bases) 418 __deregister_frame_info_bases (__EH_FRAME_BEGIN__); 419 #else 420 if (__deregister_frame_info) 421 __deregister_frame_info (__EH_FRAME_BEGIN__); 422 #endif 423 #endif 424 425 completed = 1; 426 } 427 428 /* Stick a call to __do_global_dtors_aux into the .fini section. */ 429 #ifdef FINI_SECTION_ASM_OP 430 CRT_CALL_STATIC_FUNCTION (FINI_SECTION_ASM_OP, __do_global_dtors_aux) 431 #elif defined (FINI_ARRAY_SECTION_ASM_OP) 432 static func_ptr __do_global_dtors_aux_fini_array_entry[] 433 __attribute__ ((__used__, section(".fini_array"), aligned(sizeof(func_ptr)))) 434 = { __do_global_dtors_aux }; 435 #else /* !FINI_SECTION_ASM_OP && !FINI_ARRAY_SECTION_ASM_OP */ 436 static void __attribute__((used)) 437 __do_global_dtors_aux_1 (void) 438 { 439 atexit (__do_global_dtors_aux); 440 } 441 CRT_CALL_STATIC_FUNCTION (__LIBGCC_INIT_SECTION_ASM_OP__, 442 __do_global_dtors_aux_1) 443 #endif 444 445 #if defined(USE_EH_FRAME_REGISTRY) \ 446 || defined(USE_TM_CLONE_REGISTRY) 447 /* Stick a call to __register_frame_info into the .init section. For some 448 reason calls with no arguments work more reliably in .init, so stick the 449 call in another function. */ 450 451 static void __attribute__((used)) 452 frame_dummy (void) 453 { 454 #ifdef USE_EH_FRAME_REGISTRY 455 static struct object object; 456 #ifdef CRT_GET_RFIB_DATA 457 void *tbase, *dbase; 458 tbase = 0; 459 CRT_GET_RFIB_DATA (dbase); 460 if (__register_frame_info_bases) 461 __register_frame_info_bases (__EH_FRAME_BEGIN__, &object, tbase, dbase); 462 #else 463 if (__register_frame_info) 464 __register_frame_info (__EH_FRAME_BEGIN__, &object); 465 #endif /* CRT_GET_RFIB_DATA */ 466 #endif /* USE_EH_FRAME_REGISTRY */ 467 468 #if USE_TM_CLONE_REGISTRY 469 register_tm_clones (); 470 #endif /* USE_TM_CLONE_REGISTRY */ 471 } 472 473 #ifdef __LIBGCC_INIT_SECTION_ASM_OP__ 474 CRT_CALL_STATIC_FUNCTION (__LIBGCC_INIT_SECTION_ASM_OP__, frame_dummy) 475 #else /* defined(__LIBGCC_INIT_SECTION_ASM_OP__) */ 476 static func_ptr __frame_dummy_init_array_entry[] 477 __attribute__ ((__used__, section(".init_array"), aligned(sizeof(func_ptr)))) 478 = { frame_dummy }; 479 #endif /* !defined(__LIBGCC_INIT_SECTION_ASM_OP__) */ 480 #endif /* USE_EH_FRAME_REGISTRY || USE_TM_CLONE_REGISTRY */ 481 482 #else /* OBJECT_FORMAT_ELF */ 483 484 /* The function __do_global_ctors_aux is compiled twice (once in crtbegin.o 485 and once in crtend.o). It must be declared static to avoid a link 486 error. Here, we define __do_global_ctors as an externally callable 487 function. It is externally callable so that __main can invoke it when 488 INVOKE__main is defined. This has the additional effect of forcing cc1 489 to switch to the .text section. */ 490 491 static void __do_global_ctors_aux (void); 492 void 493 __do_global_ctors (void) 494 { 495 #ifdef INVOKE__main 496 /* If __main won't actually call __do_global_ctors then it doesn't matter 497 what's inside the function. The inside of __do_global_ctors_aux is 498 called automatically in that case. And the Alliant fx2800 linker 499 crashes on this reference. So prevent the crash. */ 500 __do_global_ctors_aux (); 501 #endif 502 } 503 504 asm (__LIBGCC_INIT_SECTION_ASM_OP__); /* cc1 doesn't know that we are switching! */ 505 506 /* A routine to invoke all of the global constructors upon entry to the 507 program. We put this into the .init section (for systems that have 508 such a thing) so that we can properly perform the construction of 509 file-scope static-storage C++ objects within shared libraries. */ 510 511 static void __attribute__((used)) 512 __do_global_ctors_aux (void) /* prologue goes in .init section */ 513 { 514 FORCE_CODE_SECTION_ALIGN /* explicit align before switch to .text */ 515 asm (__LIBGCC_TEXT_SECTION_ASM_OP__); /* don't put epilogue and body in .init */ 516 DO_GLOBAL_CTORS_BODY; 517 atexit (__do_global_dtors); 518 } 519 520 #endif /* OBJECT_FORMAT_ELF */ 521 522 #elif defined(HAS_INIT_SECTION) /* ! __LIBGCC_INIT_SECTION_ASM_OP__ */ 523 524 extern void __do_global_dtors (void); 525 526 /* This case is used by the Irix 6 port, which supports named sections but 527 not an SVR4-style .fini section. __do_global_dtors can be non-static 528 in this case because we protect it with -hidden_symbol. */ 529 530 void 531 __do_global_dtors (void) 532 { 533 func_ptr *p, f; 534 for (p = __DTOR_LIST__ + 1; (f = *p); p++) 535 f (); 536 537 #if USE_TM_CLONE_REGISTRY 538 deregister_tm_clones (); 539 #endif /* USE_TM_CLONE_REGISTRY */ 540 541 #ifdef USE_EH_FRAME_REGISTRY 542 if (__deregister_frame_info) 543 __deregister_frame_info (__EH_FRAME_BEGIN__); 544 #endif 545 } 546 547 #if defined(USE_EH_FRAME_REGISTRY) \ 548 || defined(USE_TM_CLONE_REGISTRY) 549 /* A helper function for __do_global_ctors, which is in crtend.o. Here 550 in crtbegin.o, we can reference a couple of symbols not visible there. 551 Plus, since we're before libgcc.a, we have no problems referencing 552 functions from there. */ 553 void 554 __do_global_ctors_1(void) 555 { 556 #ifdef USE_EH_FRAME_REGISTRY 557 static struct object object; 558 if (__register_frame_info) 559 __register_frame_info (__EH_FRAME_BEGIN__, &object); 560 #endif 561 562 #if USE_TM_CLONE_REGISTRY 563 register_tm_clones (); 564 #endif /* USE_TM_CLONE_REGISTRY */ 565 } 566 #endif /* USE_EH_FRAME_REGISTRY || USE_TM_CLONE_REGISTRY */ 567 568 #else /* ! __LIBGCC_INIT_SECTION_ASM_OP__ && ! HAS_INIT_SECTION */ 569 #error "What are you doing with crtstuff.c, then?" 570 #endif 571 572 #elif defined(CRT_END) /* ! CRT_BEGIN */ 573 574 /* No need for .ctors/.dtors section if linker can place them in 575 .init_array/.fini_array section. */ 576 #ifndef USE_INITFINI_ARRAY 577 /* Put a word containing zero at the end of each of our two lists of function 578 addresses. Note that the words defined here go into the .ctors and .dtors 579 sections of the crtend.o file, and since that file is always linked in 580 last, these words naturally end up at the very ends of the two lists 581 contained in these two sections. */ 582 583 #ifdef CTOR_LIST_END 584 CTOR_LIST_END; 585 #elif defined(__LIBGCC_CTORS_SECTION_ASM_OP__) 586 /* Hack: force cc1 to switch to .data section early, so that assembling 587 __CTOR_LIST__ does not undo our behind-the-back change to .ctors. */ 588 static func_ptr force_to_data[1] __attribute__ ((__used__)) = { }; 589 asm (__LIBGCC_CTORS_SECTION_ASM_OP__); 590 STATIC func_ptr __CTOR_END__[1] 591 __attribute__((aligned(sizeof(func_ptr)))) 592 = { (func_ptr) 0 }; 593 #else 594 STATIC func_ptr __CTOR_END__[1] 595 __attribute__((section(".ctors"), aligned(sizeof(func_ptr)))) 596 = { (func_ptr) 0 }; 597 #endif 598 599 #ifdef DTOR_LIST_END 600 DTOR_LIST_END; 601 #elif defined(HIDDEN_DTOR_LIST_END) 602 #ifdef __LIBGCC_DTORS_SECTION_ASM_OP__ 603 asm (__LIBGCC_DTORS_SECTION_ASM_OP__); 604 #endif 605 func_ptr __DTOR_END__[1] 606 __attribute__ ((used, 607 #ifndef __LIBGCC_DTORS_SECTION_ASM_OP__ 608 section(".dtors"), 609 #endif 610 aligned(sizeof(func_ptr)), visibility ("hidden"))) 611 = { (func_ptr) 0 }; 612 #elif defined(__LIBGCC_DTORS_SECTION_ASM_OP__) 613 asm (__LIBGCC_DTORS_SECTION_ASM_OP__); 614 STATIC func_ptr __DTOR_END__[1] 615 __attribute__ ((used, aligned(sizeof(func_ptr)))) 616 = { (func_ptr) 0 }; 617 #else 618 STATIC func_ptr __DTOR_END__[1] 619 __attribute__((used, section(".dtors"), aligned(sizeof(func_ptr)))) 620 = { (func_ptr) 0 }; 621 #endif 622 #endif /* USE_INITFINI_ARRAY */ 623 624 #ifdef __LIBGCC_EH_FRAME_SECTION_NAME__ 625 /* Terminate the frame unwind info section with a 4byte 0 as a sentinel; 626 this would be the 'length' field in a real FDE. */ 627 # if __INT_MAX__ == 2147483647 628 typedef int int32; 629 # elif __LONG_MAX__ == 2147483647 630 typedef long int32; 631 # elif __SHRT_MAX__ == 2147483647 632 typedef short int32; 633 # else 634 # error "Missing a 4 byte integer" 635 # endif 636 STATIC EH_FRAME_SECTION_CONST int32 __FRAME_END__[] 637 __attribute__ ((used, section(__LIBGCC_EH_FRAME_SECTION_NAME__), 638 aligned(sizeof(int32)))) 639 = { 0 }; 640 #endif /* __LIBGCC_EH_FRAME_SECTION_NAME__ */ 641 642 #if USE_TM_CLONE_REGISTRY 643 # ifndef HAVE_GAS_HIDDEN 644 static 645 # endif 646 func_ptr __TMC_END__[] 647 __attribute__((used, section(".tm_clone_table"), aligned(sizeof(void *)))) 648 # ifdef HAVE_GAS_HIDDEN 649 __attribute__((__visibility__ ("hidden"))) = { }; 650 # else 651 = { 0, 0 }; 652 # endif 653 #endif /* USE_TM_CLONE_REGISTRY */ 654 655 #ifdef __LIBGCC_INIT_ARRAY_SECTION_ASM_OP__ 656 657 /* If we are using .init_array, there is nothing to do. */ 658 659 #elif defined(__LIBGCC_INIT_SECTION_ASM_OP__) 660 661 #ifdef OBJECT_FORMAT_ELF 662 static void __attribute__((used)) 663 __do_global_ctors_aux (void) 664 { 665 func_ptr *p; 666 for (p = __CTOR_END__ - 1; *p != (func_ptr) -1; p--) 667 (*p) (); 668 } 669 670 /* Stick a call to __do_global_ctors_aux into the .init section. */ 671 CRT_CALL_STATIC_FUNCTION (__LIBGCC_INIT_SECTION_ASM_OP__, __do_global_ctors_aux) 672 #else /* OBJECT_FORMAT_ELF */ 673 674 /* Stick the real initialization code, followed by a normal sort of 675 function epilogue at the very end of the .init section for this 676 entire root executable file or for this entire shared library file. 677 678 Note that we use some tricks here to get *just* the body and just 679 a function epilogue (but no function prologue) into the .init 680 section of the crtend.o file. Specifically, we switch to the .text 681 section, start to define a function, and then we switch to the .init 682 section just before the body code. 683 684 Earlier on, we put the corresponding function prologue into the .init 685 section of the crtbegin.o file (which will be linked in first). 686 687 Note that we want to invoke all constructors for C++ file-scope static- 688 storage objects AFTER any other possible initialization actions which 689 may be performed by the code in the .init section contributions made by 690 other libraries, etc. That's because those other initializations may 691 include setup operations for very primitive things (e.g. initializing 692 the state of the floating-point coprocessor, etc.) which should be done 693 before we start to execute any of the user's code. */ 694 695 static void 696 __do_global_ctors_aux (void) /* prologue goes in .text section */ 697 { 698 asm (__LIBGCC_INIT_SECTION_ASM_OP__); 699 DO_GLOBAL_CTORS_BODY; 700 atexit (__do_global_dtors); 701 } /* epilogue and body go in .init section */ 702 703 FORCE_CODE_SECTION_ALIGN 704 asm (__LIBGCC_TEXT_SECTION_ASM_OP__); 705 706 #endif /* OBJECT_FORMAT_ELF */ 707 708 #elif defined(HAS_INIT_SECTION) /* ! __LIBGCC_INIT_SECTION_ASM_OP__ */ 709 710 extern void __do_global_ctors (void); 711 712 /* This case is used by the Irix 6 port, which supports named sections but 713 not an SVR4-style .init section. __do_global_ctors can be non-static 714 in this case because we protect it with -hidden_symbol. */ 715 void 716 __do_global_ctors (void) 717 { 718 func_ptr *p; 719 #if defined(USE_EH_FRAME_REGISTRY) \ 720 || defined(USE_TM_CLONE_REGISTRY) 721 __do_global_ctors_1(); 722 #endif 723 for (p = __CTOR_END__ - 1; *p != (func_ptr) -1; p--) 724 (*p) (); 725 } 726 727 #else /* ! __LIBGCC_INIT_SECTION_ASM_OP__ && ! HAS_INIT_SECTION */ 728 #error "What are you doing with crtstuff.c, then?" 729 #endif 730 731 #else /* ! CRT_BEGIN && ! CRT_END */ 732 #error "One of CRT_BEGIN or CRT_END must be defined." 733 #endif 734