1 /* Definitions for symbol file management in GDB. 2 3 Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 4 2002, 2003, 2004, 2007, 2008, 2009 Free Software Foundation, Inc. 5 6 This file is part of GDB. 7 8 This program is free software; you can redistribute it and/or modify 9 it under the terms of the GNU General Public License as published by 10 the Free Software Foundation; either version 3 of the License, or 11 (at your option) any later version. 12 13 This program is distributed in the hope that it will be useful, 14 but WITHOUT ANY WARRANTY; without even the implied warranty of 15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 GNU General Public License for more details. 17 18 You should have received a copy of the GNU General Public License 19 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 20 21 #if !defined (OBJFILES_H) 22 #define OBJFILES_H 23 24 #include "gdb_obstack.h" /* For obstack internals. */ 25 #include "symfile.h" /* For struct psymbol_allocation_list */ 26 27 struct bcache; 28 struct htab; 29 struct symtab; 30 struct objfile_data; 31 32 /* This structure maintains information on a per-objfile basis about the 33 "entry point" of the objfile, and the scope within which the entry point 34 exists. It is possible that gdb will see more than one objfile that is 35 executable, each with its own entry point. 36 37 For example, for dynamically linked executables in SVR4, the dynamic linker 38 code is contained within the shared C library, which is actually executable 39 and is run by the kernel first when an exec is done of a user executable 40 that is dynamically linked. The dynamic linker within the shared C library 41 then maps in the various program segments in the user executable and jumps 42 to the user executable's recorded entry point, as if the call had been made 43 directly by the kernel. 44 45 The traditional gdb method of using this info was to use the 46 recorded entry point to set the entry-file's lowpc and highpc from 47 the debugging information, where these values are the starting 48 address (inclusive) and ending address (exclusive) of the 49 instruction space in the executable which correspond to the 50 "startup file", I.E. crt0.o in most cases. This file is assumed to 51 be a startup file and frames with pc's inside it are treated as 52 nonexistent. Setting these variables is necessary so that 53 backtraces do not fly off the bottom of the stack. 54 55 NOTE: cagney/2003-09-09: It turns out that this "traditional" 56 method doesn't work. Corinna writes: ``It turns out that the call 57 to test for "inside entry file" destroys a meaningful backtrace 58 under some conditions. E. g. the backtrace tests in the asm-source 59 testcase are broken for some targets. In this test the functions 60 are all implemented as part of one file and the testcase is not 61 necessarily linked with a start file (depending on the target). 62 What happens is, that the first frame is printed normaly and 63 following frames are treated as being inside the enttry file then. 64 This way, only the #0 frame is printed in the backtrace output.'' 65 Ref "frame.c" "NOTE: vinschen/2003-04-01". 66 67 Gdb also supports an alternate method to avoid running off the bottom 68 of the stack. 69 70 There are two frames that are "special", the frame for the function 71 containing the process entry point, since it has no predecessor frame, 72 and the frame for the function containing the user code entry point 73 (the main() function), since all the predecessor frames are for the 74 process startup code. Since we have no guarantee that the linked 75 in startup modules have any debugging information that gdb can use, 76 we need to avoid following frame pointers back into frames that might 77 have been built in the startup code, as we might get hopelessly 78 confused. However, we almost always have debugging information 79 available for main(). 80 81 These variables are used to save the range of PC values which are 82 valid within the main() function and within the function containing 83 the process entry point. If we always consider the frame for 84 main() as the outermost frame when debugging user code, and the 85 frame for the process entry point function as the outermost frame 86 when debugging startup code, then all we have to do is have 87 DEPRECATED_FRAME_CHAIN_VALID return false whenever a frame's 88 current PC is within the range specified by these variables. In 89 essence, we set "ceilings" in the frame chain beyond which we will 90 not proceed when following the frame chain back up the stack. 91 92 A nice side effect is that we can still debug startup code without 93 running off the end of the frame chain, assuming that we have usable 94 debugging information in the startup modules, and if we choose to not 95 use the block at main, or can't find it for some reason, everything 96 still works as before. And if we have no startup code debugging 97 information but we do have usable information for main(), backtraces 98 from user code don't go wandering off into the startup code. */ 99 100 struct entry_info 101 { 102 103 /* The value we should use for this objects entry point. 104 The illegal/unknown value needs to be something other than 0, ~0 105 for instance, which is much less likely than 0. */ 106 107 CORE_ADDR entry_point; 108 109 #define INVALID_ENTRY_POINT (~0) /* ~0 will not be in any file, we hope. */ 110 111 }; 112 113 /* Sections in an objfile. The section offsets are stored in the 114 OBJFILE. */ 115 116 struct obj_section 117 { 118 struct bfd_section *the_bfd_section; /* BFD section pointer */ 119 120 /* Objfile this section is part of. */ 121 struct objfile *objfile; 122 123 /* True if this "overlay section" is mapped into an "overlay region". */ 124 int ovly_mapped; 125 }; 126 127 /* Relocation offset applied to S. */ 128 #define obj_section_offset(s) \ 129 (((s)->objfile->section_offsets)->offsets[(s)->the_bfd_section->index]) 130 131 /* The memory address of section S (vma + offset). */ 132 #define obj_section_addr(s) \ 133 (bfd_get_section_vma ((s)->objfile->abfd, s->the_bfd_section) \ 134 + obj_section_offset (s)) 135 136 /* The one-passed-the-end memory address of section S 137 (vma + size + offset). */ 138 #define obj_section_endaddr(s) \ 139 (bfd_get_section_vma ((s)->objfile->abfd, s->the_bfd_section) \ 140 + bfd_get_section_size ((s)->the_bfd_section) \ 141 + obj_section_offset (s)) 142 143 /* The "objstats" structure provides a place for gdb to record some 144 interesting information about its internal state at runtime, on a 145 per objfile basis, such as information about the number of symbols 146 read, size of string table (if any), etc. */ 147 148 struct objstats 149 { 150 int n_minsyms; /* Number of minimal symbols read */ 151 int n_psyms; /* Number of partial symbols read */ 152 int n_syms; /* Number of full symbols read */ 153 int n_stabs; /* Number of ".stabs" read (if applicable) */ 154 int n_types; /* Number of types */ 155 int sz_strtab; /* Size of stringtable, (if applicable) */ 156 }; 157 158 #define OBJSTAT(objfile, expr) (objfile -> stats.expr) 159 #define OBJSTATS struct objstats stats 160 extern void print_objfile_statistics (void); 161 extern void print_symbol_bcache_statistics (void); 162 163 /* Number of entries in the minimal symbol hash table. */ 164 #define MINIMAL_SYMBOL_HASH_SIZE 2039 165 166 /* Master structure for keeping track of each file from which 167 gdb reads symbols. There are several ways these get allocated: 1. 168 The main symbol file, symfile_objfile, set by the symbol-file command, 169 2. Additional symbol files added by the add-symbol-file command, 170 3. Shared library objfiles, added by ADD_SOLIB, 4. symbol files 171 for modules that were loaded when GDB attached to a remote system 172 (see remote-vx.c). */ 173 174 struct objfile 175 { 176 177 /* All struct objfile's are chained together by their next pointers. 178 The global variable "object_files" points to the first link in this 179 chain. 180 181 FIXME: There is a problem here if the objfile is reusable, and if 182 multiple users are to be supported. The problem is that the objfile 183 list is linked through a member of the objfile struct itself, which 184 is only valid for one gdb process. The list implementation needs to 185 be changed to something like: 186 187 struct list {struct list *next; struct objfile *objfile}; 188 189 where the list structure is completely maintained separately within 190 each gdb process. */ 191 192 struct objfile *next; 193 194 /* The object file's name, tilde-expanded and absolute. 195 Malloc'd; free it if you free this struct. */ 196 197 char *name; 198 199 /* Some flag bits for this objfile. */ 200 201 unsigned short flags; 202 203 /* Each objfile points to a linked list of symtabs derived from this file, 204 one symtab structure for each compilation unit (source file). Each link 205 in the symtab list contains a backpointer to this objfile. */ 206 207 struct symtab *symtabs; 208 209 /* Each objfile points to a linked list of partial symtabs derived from 210 this file, one partial symtab structure for each compilation unit 211 (source file). */ 212 213 struct partial_symtab *psymtabs; 214 215 /* Map addresses to the entries of PSYMTABS. It would be more efficient to 216 have a map per the whole process but ADDRMAP cannot selectively remove 217 its items during FREE_OBJFILE. This mapping is already present even for 218 PARTIAL_SYMTABs which still have no corresponding full SYMTABs read. */ 219 220 struct addrmap *psymtabs_addrmap; 221 222 /* List of freed partial symtabs, available for re-use */ 223 224 struct partial_symtab *free_psymtabs; 225 226 /* The object file's BFD. Can be null if the objfile contains only 227 minimal symbols, e.g. the run time common symbols for SunOS4. */ 228 229 bfd *obfd; 230 231 /* The gdbarch associated with the BFD. Note that this gdbarch is 232 determined solely from BFD information, without looking at target 233 information. The gdbarch determined from a running target may 234 differ from this e.g. with respect to register types and names. */ 235 236 struct gdbarch *gdbarch; 237 238 /* The modification timestamp of the object file, as of the last time 239 we read its symbols. */ 240 241 long mtime; 242 243 /* Obstack to hold objects that should be freed when we load a new symbol 244 table from this object file. */ 245 246 struct obstack objfile_obstack; 247 248 /* A byte cache where we can stash arbitrary "chunks" of bytes that 249 will not change. */ 250 251 struct bcache *psymbol_cache; /* Byte cache for partial syms */ 252 struct bcache *macro_cache; /* Byte cache for macros */ 253 254 /* Hash table for mapping symbol names to demangled names. Each 255 entry in the hash table is actually two consecutive strings, 256 both null-terminated; the first one is a mangled or linkage 257 name, and the second is the demangled name or just a zero byte 258 if the name doesn't demangle. */ 259 struct htab *demangled_names_hash; 260 261 /* Vectors of all partial symbols read in from file. The actual data 262 is stored in the objfile_obstack. */ 263 264 struct psymbol_allocation_list global_psymbols; 265 struct psymbol_allocation_list static_psymbols; 266 267 /* Each file contains a pointer to an array of minimal symbols for all 268 global symbols that are defined within the file. The array is terminated 269 by a "null symbol", one that has a NULL pointer for the name and a zero 270 value for the address. This makes it easy to walk through the array 271 when passed a pointer to somewhere in the middle of it. There is also 272 a count of the number of symbols, which does not include the terminating 273 null symbol. The array itself, as well as all the data that it points 274 to, should be allocated on the objfile_obstack for this file. */ 275 276 struct minimal_symbol *msymbols; 277 int minimal_symbol_count; 278 279 /* This is a hash table used to index the minimal symbols by name. */ 280 281 struct minimal_symbol *msymbol_hash[MINIMAL_SYMBOL_HASH_SIZE]; 282 283 /* This hash table is used to index the minimal symbols by their 284 demangled names. */ 285 286 struct minimal_symbol *msymbol_demangled_hash[MINIMAL_SYMBOL_HASH_SIZE]; 287 288 /* Structure which keeps track of functions that manipulate objfile's 289 of the same type as this objfile. I.E. the function to read partial 290 symbols for example. Note that this structure is in statically 291 allocated memory, and is shared by all objfiles that use the 292 object module reader of this type. */ 293 294 struct sym_fns *sf; 295 296 /* The per-objfile information about the entry point, the scope (file/func) 297 containing the entry point, and the scope of the user's main() func. */ 298 299 struct entry_info ei; 300 301 /* Information about stabs. Will be filled in with a dbx_symfile_info 302 struct by those readers that need it. */ 303 /* NOTE: cagney/2004-10-23: This has been replaced by per-objfile 304 data points implemented using "data" and "num_data" below. For 305 an example of how to use this replacement, see "objfile_data" 306 in "mips-tdep.c". */ 307 308 struct dbx_symfile_info *deprecated_sym_stab_info; 309 310 /* Hook for information for use by the symbol reader (currently used 311 for information shared by sym_init and sym_read). It is 312 typically a pointer to malloc'd memory. The symbol reader's finish 313 function is responsible for freeing the memory thusly allocated. */ 314 /* NOTE: cagney/2004-10-23: This has been replaced by per-objfile 315 data points implemented using "data" and "num_data" below. For 316 an example of how to use this replacement, see "objfile_data" 317 in "mips-tdep.c". */ 318 319 void *deprecated_sym_private; 320 321 /* Per objfile data-pointers required by other GDB modules. */ 322 /* FIXME: kettenis/20030711: This mechanism could replace 323 deprecated_sym_stab_info and deprecated_sym_private 324 entirely. */ 325 326 void **data; 327 unsigned num_data; 328 329 /* Set of relocation offsets to apply to each section. 330 Currently on the objfile_obstack (which makes no sense, but I'm 331 not sure it's harming anything). 332 333 These offsets indicate that all symbols (including partial and 334 minimal symbols) which have been read have been relocated by this 335 much. Symbols which are yet to be read need to be relocated by 336 it. */ 337 338 struct section_offsets *section_offsets; 339 int num_sections; 340 341 /* Indexes in the section_offsets array. These are initialized by the 342 *_symfile_offsets() family of functions (som_symfile_offsets, 343 xcoff_symfile_offsets, default_symfile_offsets). In theory they 344 should correspond to the section indexes used by bfd for the 345 current objfile. The exception to this for the time being is the 346 SOM version. */ 347 348 int sect_index_text; 349 int sect_index_data; 350 int sect_index_bss; 351 int sect_index_rodata; 352 353 /* These pointers are used to locate the section table, which 354 among other things, is used to map pc addresses into sections. 355 SECTIONS points to the first entry in the table, and 356 SECTIONS_END points to the first location past the last entry 357 in the table. Currently the table is stored on the 358 objfile_obstack (which makes no sense, but I'm not sure it's 359 harming anything). */ 360 361 struct obj_section 362 *sections, *sections_end; 363 364 /* Link to objfile that contains the debug symbols for this one. 365 One is loaded if this file has an debug link to an existing 366 debug file with the right checksum */ 367 struct objfile *separate_debug_objfile; 368 369 /* If this is a separate debug object, this is used as a link to the 370 actual executable objfile. */ 371 struct objfile *separate_debug_objfile_backlink; 372 373 /* Place to stash various statistics about this objfile */ 374 OBJSTATS; 375 376 /* A symtab that the C++ code uses to stash special symbols 377 associated to namespaces. */ 378 379 /* FIXME/carlton-2003-06-27: Delete this in a few years once 380 "possible namespace symbols" go away. */ 381 struct symtab *cp_namespace_symtab; 382 }; 383 384 /* Defines for the objfile flag word. */ 385 386 /* When an object file has its functions reordered (currently Irix-5.2 387 shared libraries exhibit this behaviour), we will need an expensive 388 algorithm to locate a partial symtab or symtab via an address. 389 To avoid this penalty for normal object files, we use this flag, 390 whose setting is determined upon symbol table read in. */ 391 392 #define OBJF_REORDERED (1 << 0) /* Functions are reordered */ 393 394 /* Distinguish between an objfile for a shared library and a "vanilla" 395 objfile. (If not set, the objfile may still actually be a solib. 396 This can happen if the user created the objfile by using the 397 add-symbol-file command. GDB doesn't in that situation actually 398 check whether the file is a solib. Rather, the target's 399 implementation of the solib interface is responsible for setting 400 this flag when noticing solibs used by an inferior.) */ 401 402 #define OBJF_SHARED (1 << 1) /* From a shared library */ 403 404 /* User requested that this objfile be read in it's entirety. */ 405 406 #define OBJF_READNOW (1 << 2) /* Immediate full read */ 407 408 /* This objfile was created because the user explicitly caused it 409 (e.g., used the add-symbol-file command). This bit offers a way 410 for run_command to remove old objfile entries which are no longer 411 valid (i.e., are associated with an old inferior), but to preserve 412 ones that the user explicitly loaded via the add-symbol-file 413 command. */ 414 415 #define OBJF_USERLOADED (1 << 3) /* User loaded */ 416 417 /* The object file that the main symbol table was loaded from (e.g. the 418 argument to the "symbol-file" or "file" command). */ 419 420 extern struct objfile *symfile_objfile; 421 422 /* The object file that contains the runtime common minimal symbols 423 for SunOS4. Note that this objfile has no associated BFD. */ 424 425 extern struct objfile *rt_common_objfile; 426 427 /* When we need to allocate a new type, we need to know which objfile_obstack 428 to allocate the type on, since there is one for each objfile. The places 429 where types are allocated are deeply buried in function call hierarchies 430 which know nothing about objfiles, so rather than trying to pass a 431 particular objfile down to them, we just do an end run around them and 432 set current_objfile to be whatever objfile we expect to be using at the 433 time types are being allocated. For instance, when we start reading 434 symbols for a particular objfile, we set current_objfile to point to that 435 objfile, and when we are done, we set it back to NULL, to ensure that we 436 never put a type someplace other than where we are expecting to put it. 437 FIXME: Maybe we should review the entire type handling system and 438 see if there is a better way to avoid this problem. */ 439 440 extern struct objfile *current_objfile; 441 442 /* All known objfiles are kept in a linked list. This points to the 443 root of this list. */ 444 445 extern struct objfile *object_files; 446 447 /* Declarations for functions defined in objfiles.c */ 448 449 extern struct objfile *allocate_objfile (bfd *, int); 450 451 extern struct gdbarch *get_objfile_arch (struct objfile *); 452 453 extern void init_entry_point_info (struct objfile *); 454 455 extern CORE_ADDR entry_point_address (void); 456 457 extern int build_objfile_section_table (struct objfile *); 458 459 extern void terminate_minimal_symbol_table (struct objfile *objfile); 460 461 extern void put_objfile_before (struct objfile *, struct objfile *); 462 463 extern void objfile_to_front (struct objfile *); 464 465 extern void unlink_objfile (struct objfile *); 466 467 extern void free_objfile (struct objfile *); 468 469 extern struct cleanup *make_cleanup_free_objfile (struct objfile *); 470 471 extern void free_all_objfiles (void); 472 473 extern void objfile_relocate (struct objfile *, struct section_offsets *); 474 475 extern int objfile_has_partial_symbols (struct objfile *objfile); 476 477 extern int objfile_has_full_symbols (struct objfile *objfile); 478 479 extern int have_partial_symbols (void); 480 481 extern int have_full_symbols (void); 482 483 extern void objfiles_changed (void); 484 485 /* This operation deletes all objfile entries that represent solibs that 486 weren't explicitly loaded by the user, via e.g., the add-symbol-file 487 command. 488 */ 489 extern void objfile_purge_solibs (void); 490 491 /* Functions for dealing with the minimal symbol table, really a misc 492 address<->symbol mapping for things we don't have debug symbols for. */ 493 494 extern int have_minimal_symbols (void); 495 496 extern struct obj_section *find_pc_section (CORE_ADDR pc); 497 498 extern int in_plt_section (CORE_ADDR, char *); 499 500 /* Keep a registry of per-objfile data-pointers required by other GDB 501 modules. */ 502 503 /* Allocate an entry in the per-objfile registry. */ 504 extern const struct objfile_data *register_objfile_data (void); 505 506 /* Allocate an entry in the per-objfile registry. 507 SAVE and FREE are called when clearing objfile data. 508 First all registered SAVE functions are called. 509 Then all registered FREE functions are called. 510 Either or both of SAVE, FREE may be NULL. */ 511 extern const struct objfile_data *register_objfile_data_with_cleanup 512 (void (*save) (struct objfile *, void *), 513 void (*free) (struct objfile *, void *)); 514 515 extern void clear_objfile_data (struct objfile *objfile); 516 extern void set_objfile_data (struct objfile *objfile, 517 const struct objfile_data *data, void *value); 518 extern void *objfile_data (struct objfile *objfile, 519 const struct objfile_data *data); 520 521 extern struct bfd *gdb_bfd_ref (struct bfd *abfd); 522 extern void gdb_bfd_unref (struct bfd *abfd); 523 524 525 /* Traverse all object files. ALL_OBJFILES_SAFE works even if you delete 526 the objfile during the traversal. */ 527 528 #define ALL_OBJFILES(obj) \ 529 for ((obj) = object_files; (obj) != NULL; (obj) = (obj)->next) 530 531 #define ALL_OBJFILES_SAFE(obj,nxt) \ 532 for ((obj) = object_files; \ 533 (obj) != NULL? ((nxt)=(obj)->next,1) :0; \ 534 (obj) = (nxt)) 535 536 /* Traverse all symtabs in one objfile. */ 537 538 #define ALL_OBJFILE_SYMTABS(objfile, s) \ 539 for ((s) = (objfile) -> symtabs; (s) != NULL; (s) = (s) -> next) 540 541 /* Traverse all psymtabs in one objfile. */ 542 543 #define ALL_OBJFILE_PSYMTABS(objfile, p) \ 544 for ((p) = (objfile) -> psymtabs; (p) != NULL; (p) = (p) -> next) 545 546 /* Traverse all minimal symbols in one objfile. */ 547 548 #define ALL_OBJFILE_MSYMBOLS(objfile, m) \ 549 for ((m) = (objfile) -> msymbols; SYMBOL_LINKAGE_NAME(m) != NULL; (m)++) 550 551 /* Traverse all symtabs in all objfiles. */ 552 553 #define ALL_SYMTABS(objfile, s) \ 554 ALL_OBJFILES (objfile) \ 555 ALL_OBJFILE_SYMTABS (objfile, s) 556 557 /* Traverse all symtabs in all objfiles, skipping included files 558 (which share a blockvector with their primary symtab). */ 559 560 #define ALL_PRIMARY_SYMTABS(objfile, s) \ 561 ALL_OBJFILES (objfile) \ 562 ALL_OBJFILE_SYMTABS (objfile, s) \ 563 if ((s)->primary) 564 565 /* Traverse all psymtabs in all objfiles. */ 566 567 #define ALL_PSYMTABS(objfile, p) \ 568 ALL_OBJFILES (objfile) \ 569 ALL_OBJFILE_PSYMTABS (objfile, p) 570 571 /* Traverse all minimal symbols in all objfiles. */ 572 573 #define ALL_MSYMBOLS(objfile, m) \ 574 ALL_OBJFILES (objfile) \ 575 ALL_OBJFILE_MSYMBOLS (objfile, m) 576 577 #define ALL_OBJFILE_OSECTIONS(objfile, osect) \ 578 for (osect = objfile->sections; osect < objfile->sections_end; osect++) 579 580 #define ALL_OBJSECTIONS(objfile, osect) \ 581 ALL_OBJFILES (objfile) \ 582 ALL_OBJFILE_OSECTIONS (objfile, osect) 583 584 #define SECT_OFF_DATA(objfile) \ 585 ((objfile->sect_index_data == -1) \ 586 ? (internal_error (__FILE__, __LINE__, _("sect_index_data not initialized")), -1) \ 587 : objfile->sect_index_data) 588 589 #define SECT_OFF_RODATA(objfile) \ 590 ((objfile->sect_index_rodata == -1) \ 591 ? (internal_error (__FILE__, __LINE__, _("sect_index_rodata not initialized")), -1) \ 592 : objfile->sect_index_rodata) 593 594 #define SECT_OFF_TEXT(objfile) \ 595 ((objfile->sect_index_text == -1) \ 596 ? (internal_error (__FILE__, __LINE__, _("sect_index_text not initialized")), -1) \ 597 : objfile->sect_index_text) 598 599 /* Sometimes the .bss section is missing from the objfile, so we don't 600 want to die here. Let the users of SECT_OFF_BSS deal with an 601 uninitialized section index. */ 602 #define SECT_OFF_BSS(objfile) (objfile)->sect_index_bss 603 604 /* Answer whether there is more than one object file loaded. */ 605 606 #define MULTI_OBJFILE_P() (object_files && object_files->next) 607 608 #endif /* !defined (OBJFILES_H) */ 609