1 /* Definitions for symbol file management in GDB.
3 Copyright (C) 1992-2017 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
20 #if !defined (OBJFILES_H)
24 #include "gdb_obstack.h" /* For obstack internals. */
25 #include "objfile-flags.h"
27 #include "progspace.h"
34 struct partial_symbol;
36 /* This structure maintains information on a per-objfile basis about the
37 "entry point" of the objfile, and the scope within which the entry point
38 exists. It is possible that gdb will see more than one objfile that is
39 executable, each with its own entry point.
41 For example, for dynamically linked executables in SVR4, the dynamic linker
42 code is contained within the shared C library, which is actually executable
43 and is run by the kernel first when an exec is done of a user executable
44 that is dynamically linked. The dynamic linker within the shared C library
45 then maps in the various program segments in the user executable and jumps
46 to the user executable's recorded entry point, as if the call had been made
47 directly by the kernel.
49 The traditional gdb method of using this info was to use the
50 recorded entry point to set the entry-file's lowpc and highpc from
51 the debugging information, where these values are the starting
52 address (inclusive) and ending address (exclusive) of the
53 instruction space in the executable which correspond to the
54 "startup file", i.e. crt0.o in most cases. This file is assumed to
55 be a startup file and frames with pc's inside it are treated as
56 nonexistent. Setting these variables is necessary so that
57 backtraces do not fly off the bottom of the stack.
59 NOTE: cagney/2003-09-09: It turns out that this "traditional"
60 method doesn't work. Corinna writes: ``It turns out that the call
61 to test for "inside entry file" destroys a meaningful backtrace
62 under some conditions. E.g. the backtrace tests in the asm-source
63 testcase are broken for some targets. In this test the functions
64 are all implemented as part of one file and the testcase is not
65 necessarily linked with a start file (depending on the target).
66 What happens is, that the first frame is printed normaly and
67 following frames are treated as being inside the enttry file then.
68 This way, only the #0 frame is printed in the backtrace output.''
69 Ref "frame.c" "NOTE: vinschen/2003-04-01".
71 Gdb also supports an alternate method to avoid running off the bottom
74 There are two frames that are "special", the frame for the function
75 containing the process entry point, since it has no predecessor frame,
76 and the frame for the function containing the user code entry point
77 (the main() function), since all the predecessor frames are for the
78 process startup code. Since we have no guarantee that the linked
79 in startup modules have any debugging information that gdb can use,
80 we need to avoid following frame pointers back into frames that might
81 have been built in the startup code, as we might get hopelessly
82 confused. However, we almost always have debugging information
85 These variables are used to save the range of PC values which are
86 valid within the main() function and within the function containing
87 the process entry point. If we always consider the frame for
88 main() as the outermost frame when debugging user code, and the
89 frame for the process entry point function as the outermost frame
90 when debugging startup code, then all we have to do is have
91 DEPRECATED_FRAME_CHAIN_VALID return false whenever a frame's
92 current PC is within the range specified by these variables. In
93 essence, we set "ceilings" in the frame chain beyond which we will
94 not proceed when following the frame chain back up the stack.
96 A nice side effect is that we can still debug startup code without
97 running off the end of the frame chain, assuming that we have usable
98 debugging information in the startup modules, and if we choose to not
99 use the block at main, or can't find it for some reason, everything
100 still works as before. And if we have no startup code debugging
101 information but we do have usable information for main(), backtraces
102 from user code don't go wandering off into the startup code. */
106 /* The unrelocated value we should use for this objfile entry point. */
107 CORE_ADDR entry_point;
109 /* The index of the section in which the entry point appears. */
110 int the_bfd_section_index;
112 /* Set to 1 iff ENTRY_POINT contains a valid value. */
113 unsigned entry_point_p : 1;
115 /* Set to 1 iff this object was initialized. */
116 unsigned initialized : 1;
119 /* Sections in an objfile. The section offsets are stored in the
124 /* BFD section pointer */
125 struct bfd_section *the_bfd_section;
127 /* Objfile this section is part of. */
128 struct objfile *objfile;
130 /* True if this "overlay section" is mapped into an "overlay region". */
134 /* Relocation offset applied to S. */
135 #define obj_section_offset(s) \
136 (((s)->objfile->section_offsets)->offsets[gdb_bfd_section_index ((s)->objfile->obfd, (s)->the_bfd_section)])
138 /* The memory address of section S (vma + offset). */
139 #define obj_section_addr(s) \
140 (bfd_get_section_vma ((s)->objfile->obfd, s->the_bfd_section) \
141 + obj_section_offset (s))
143 /* The one-passed-the-end memory address of section S
144 (vma + size + offset). */
145 #define obj_section_endaddr(s) \
146 (bfd_get_section_vma ((s)->objfile->obfd, s->the_bfd_section) \
147 + bfd_get_section_size ((s)->the_bfd_section) \
148 + obj_section_offset (s))
150 /* The "objstats" structure provides a place for gdb to record some
151 interesting information about its internal state at runtime, on a
152 per objfile basis, such as information about the number of symbols
153 read, size of string table (if any), etc. */
157 /* Number of partial symbols read. */
160 /* Number of full symbols read. */
163 /* Number of ".stabs" read (if applicable). */
166 /* Number of types. */
169 /* Size of stringtable, (if applicable). */
173 #define OBJSTAT(objfile, expr) (objfile -> stats.expr)
174 #define OBJSTATS struct objstats stats
175 extern void print_objfile_statistics (void);
176 extern void print_symbol_bcache_statistics (void);
178 /* Number of entries in the minimal symbol hash table. */
179 #define MINIMAL_SYMBOL_HASH_SIZE 2039
181 /* Some objfile data is hung off the BFD. This enables sharing of the
182 data across all objfiles using the BFD. The data is stored in an
183 instance of this structure, and associated with the BFD using the
186 struct objfile_per_bfd_storage
188 objfile_per_bfd_storage ()
189 : minsyms_read (false)
192 /* The storage has an obstack of its own. */
194 auto_obstack storage_obstack;
196 /* Byte cache for file names. */
198 bcache *filename_cache = NULL;
200 /* Byte cache for macros. */
202 bcache *macro_cache = NULL;
204 /* The gdbarch associated with the BFD. Note that this gdbarch is
205 determined solely from BFD information, without looking at target
206 information. The gdbarch determined from a running target may
207 differ from this e.g. with respect to register types and names. */
209 struct gdbarch *gdbarch = NULL;
211 /* Hash table for mapping symbol names to demangled names. Each
212 entry in the hash table is actually two consecutive strings,
213 both null-terminated; the first one is a mangled or linkage
214 name, and the second is the demangled name or just a zero byte
215 if the name doesn't demangle. */
217 htab *demangled_names_hash = NULL;
219 /* The per-objfile information about the entry point, the scope (file/func)
220 containing the entry point, and the scope of the user's main() func. */
224 /* The name and language of any "main" found in this objfile. The
225 name can be NULL, which means that the information was not
228 const char *name_of_main = NULL;
229 enum language language_of_main = language_unknown;
231 /* Each file contains a pointer to an array of minimal symbols for all
232 global symbols that are defined within the file. The array is
233 terminated by a "null symbol", one that has a NULL pointer for the
234 name and a zero value for the address. This makes it easy to walk
235 through the array when passed a pointer to somewhere in the middle
236 of it. There is also a count of the number of symbols, which does
237 not include the terminating null symbol. The array itself, as well
238 as all the data that it points to, should be allocated on the
239 objfile_obstack for this file. */
241 minimal_symbol *msymbols = NULL;
242 int minimal_symbol_count = 0;
244 /* The number of minimal symbols read, before any minimal symbol
245 de-duplication is applied. Note in particular that this has only
246 a passing relationship with the actual size of the table above;
247 use minimal_symbol_count if you need the true size. */
251 /* This is true if minimal symbols have already been read. Symbol
252 readers can use this to bypass minimal symbol reading. Also, the
253 minimal symbol table management code in minsyms.c uses this to
254 suppress new minimal symbols. You might think that MSYMBOLS or
255 MINIMAL_SYMBOL_COUNT could be used for this, but it is possible
256 for multiple readers to install minimal symbols into a given
259 bool minsyms_read : 1;
261 /* This is a hash table used to index the minimal symbols by name. */
263 minimal_symbol *msymbol_hash[MINIMAL_SYMBOL_HASH_SIZE] {};
265 /* This hash table is used to index the minimal symbols by their
268 minimal_symbol *msymbol_demangled_hash[MINIMAL_SYMBOL_HASH_SIZE] {};
271 /* Master structure for keeping track of each file from which
272 gdb reads symbols. There are several ways these get allocated: 1.
273 The main symbol file, symfile_objfile, set by the symbol-file command,
274 2. Additional symbol files added by the add-symbol-file command,
275 3. Shared library objfiles, added by ADD_SOLIB, 4. symbol files
276 for modules that were loaded when GDB attached to a remote system
277 (see remote-vx.c). */
281 objfile (bfd *, const char *, objfile_flags);
284 DISABLE_COPY_AND_ASSIGN (objfile);
286 /* All struct objfile's are chained together by their next pointers.
287 The program space field "objfiles" (frequently referenced via
288 the macro "object_files") points to the first link in this chain. */
290 struct objfile *next = nullptr;
292 /* The object file's original name as specified by the user,
293 made absolute, and tilde-expanded. However, it is not canonicalized
294 (i.e., it has not been passed through gdb_realpath).
295 This pointer is never NULL. This does not have to be freed; it is
296 guaranteed to have a lifetime at least as long as the objfile. */
298 char *original_name = nullptr;
300 CORE_ADDR addr_low = 0;
302 /* Some flag bits for this objfile. */
306 /* The program space associated with this objfile. */
308 struct program_space *pspace;
310 /* List of compunits.
311 These are used to do symbol lookups and file/line-number lookups. */
313 struct compunit_symtab *compunit_symtabs = nullptr;
315 /* Each objfile points to a linked list of partial symtabs derived from
316 this file, one partial symtab structure for each compilation unit
319 struct partial_symtab *psymtabs = nullptr;
321 /* Map addresses to the entries of PSYMTABS. It would be more efficient to
322 have a map per the whole process but ADDRMAP cannot selectively remove
323 its items during FREE_OBJFILE. This mapping is already present even for
324 PARTIAL_SYMTABs which still have no corresponding full SYMTABs read. */
326 struct addrmap *psymtabs_addrmap = nullptr;
328 /* List of freed partial symtabs, available for re-use. */
330 struct partial_symtab *free_psymtabs = nullptr;
332 /* The object file's BFD. Can be null if the objfile contains only
333 minimal symbols, e.g. the run time common symbols for SunOS4. */
337 /* The per-BFD data. Note that this is treated specially if OBFD
340 struct objfile_per_bfd_storage *per_bfd = nullptr;
342 /* The modification timestamp of the object file, as of the last time
343 we read its symbols. */
347 /* Obstack to hold objects that should be freed when we load a new symbol
348 table from this object file. */
350 struct obstack objfile_obstack {};
352 /* A byte cache where we can stash arbitrary "chunks" of bytes that
355 struct psymbol_bcache *psymbol_cache;
357 /* Vectors of all partial symbols read in from file. The actual data
358 is stored in the objfile_obstack. */
360 std::vector<partial_symbol *> global_psymbols;
361 std::vector<partial_symbol *> static_psymbols;
363 /* Structure which keeps track of functions that manipulate objfile's
364 of the same type as this objfile. I.e. the function to read partial
365 symbols for example. Note that this structure is in statically
366 allocated memory, and is shared by all objfiles that use the
367 object module reader of this type. */
369 const struct sym_fns *sf = nullptr;
371 /* Per objfile data-pointers required by other GDB modules. */
375 /* Set of relocation offsets to apply to each section.
376 The table is indexed by the_bfd_section->index, thus it is generally
377 as large as the number of sections in the binary.
378 The table is stored on the objfile_obstack.
380 These offsets indicate that all symbols (including partial and
381 minimal symbols) which have been read have been relocated by this
382 much. Symbols which are yet to be read need to be relocated by it. */
384 struct section_offsets *section_offsets = nullptr;
385 int num_sections = 0;
387 /* Indexes in the section_offsets array. These are initialized by the
388 *_symfile_offsets() family of functions (som_symfile_offsets,
389 xcoff_symfile_offsets, default_symfile_offsets). In theory they
390 should correspond to the section indexes used by bfd for the
391 current objfile. The exception to this for the time being is the
394 These are initialized to -1 so that we can later detect if they
395 are used w/o being properly assigned to. */
397 int sect_index_text = -1;
398 int sect_index_data = -1;
399 int sect_index_bss = -1;
400 int sect_index_rodata = -1;
402 /* These pointers are used to locate the section table, which
403 among other things, is used to map pc addresses into sections.
404 SECTIONS points to the first entry in the table, and
405 SECTIONS_END points to the first location past the last entry
406 in the table. The table is stored on the objfile_obstack. The
407 sections are indexed by the BFD section index; but the
408 structure data is only valid for certain sections
409 (e.g. non-empty, SEC_ALLOC). */
411 struct obj_section *sections = nullptr;
412 struct obj_section *sections_end = nullptr;
414 /* GDB allows to have debug symbols in separate object files. This is
415 used by .gnu_debuglink, ELF build id note and Mach-O OSO.
416 Although this is a tree structure, GDB only support one level
417 (ie a separate debug for a separate debug is not supported). Note that
418 separate debug object are in the main chain and therefore will be
419 visited by ALL_OBJFILES & co iterators. Separate debug objfile always
420 has a non-nul separate_debug_objfile_backlink. */
422 /* Link to the first separate debug object, if any. */
424 struct objfile *separate_debug_objfile = nullptr;
426 /* If this is a separate debug object, this is used as a link to the
427 actual executable objfile. */
429 struct objfile *separate_debug_objfile_backlink = nullptr;
431 /* If this is a separate debug object, this is a link to the next one
432 for the same executable objfile. */
434 struct objfile *separate_debug_objfile_link = nullptr;
436 /* Place to stash various statistics about this objfile. */
440 /* A linked list of symbols created when reading template types or
441 function templates. These symbols are not stored in any symbol
442 table, so we have to keep them here to relocate them
445 struct symbol *template_symbols = nullptr;
447 /* Associate a static link (struct dynamic_prop *) to all blocks (struct
448 block *) that have one.
450 In the context of nested functions (available in Pascal, Ada and GNU C,
451 for instance), a static link (as in DWARF's DW_AT_static_link attribute)
452 for a function is a way to get the frame corresponding to the enclosing
455 Very few blocks have a static link, so it's more memory efficient to
456 store these here rather than in struct block. Static links must be
457 allocated on the objfile's obstack. */
458 htab_t static_links {};
461 /* Declarations for functions defined in objfiles.c */
463 extern struct gdbarch *get_objfile_arch (const struct objfile *);
465 extern int entry_point_address_query (CORE_ADDR *entry_p);
467 extern CORE_ADDR entry_point_address (void);
469 extern void build_objfile_section_table (struct objfile *);
471 extern struct objfile *objfile_separate_debug_iterate (const struct objfile *,
472 const struct objfile *);
474 extern void put_objfile_before (struct objfile *, struct objfile *);
476 extern void add_separate_debug_objfile (struct objfile *, struct objfile *);
478 extern void unlink_objfile (struct objfile *);
480 extern void free_objfile_separate_debug (struct objfile *);
482 extern struct cleanup *make_cleanup_free_objfile (struct objfile *);
484 extern void free_all_objfiles (void);
486 extern void objfile_relocate (struct objfile *, const struct section_offsets *);
487 extern void objfile_rebase (struct objfile *, CORE_ADDR);
489 extern int objfile_has_partial_symbols (struct objfile *objfile);
491 extern int objfile_has_full_symbols (struct objfile *objfile);
493 extern int objfile_has_symbols (struct objfile *objfile);
495 extern int have_partial_symbols (void);
497 extern int have_full_symbols (void);
499 extern void objfile_set_sym_fns (struct objfile *objfile,
500 const struct sym_fns *sf);
502 extern void objfiles_changed (void);
504 extern int is_addr_in_objfile (CORE_ADDR addr, const struct objfile *objfile);
506 /* Return true if ADDRESS maps into one of the sections of a
507 OBJF_SHARED objfile of PSPACE and false otherwise. */
509 extern int shared_objfile_contains_address_p (struct program_space *pspace,
512 /* This operation deletes all objfile entries that represent solibs that
513 weren't explicitly loaded by the user, via e.g., the add-symbol-file
516 extern void objfile_purge_solibs (void);
518 /* Functions for dealing with the minimal symbol table, really a misc
519 address<->symbol mapping for things we don't have debug symbols for. */
521 extern int have_minimal_symbols (void);
523 extern struct obj_section *find_pc_section (CORE_ADDR pc);
525 /* Return non-zero if PC is in a section called NAME. */
526 extern int pc_in_section (CORE_ADDR, const char *);
528 /* Return non-zero if PC is in a SVR4-style procedure linkage table
532 in_plt_section (CORE_ADDR pc)
534 return pc_in_section (pc, ".plt");
537 /* Keep a registry of per-objfile data-pointers required by other GDB
539 DECLARE_REGISTRY(objfile);
541 /* In normal use, the section map will be rebuilt by find_pc_section
542 if objfiles have been added, removed or relocated since it was last
543 called. Calling inhibit_section_map_updates will inhibit this
544 behavior until resume_section_map_updates is called. If you call
545 inhibit_section_map_updates you must ensure that every call to
546 find_pc_section in the inhibited region relates to a section that
547 is already in the section map and has not since been removed or
549 extern void inhibit_section_map_updates (struct program_space *pspace);
551 /* Resume automatically rebuilding the section map as required. */
552 extern void resume_section_map_updates (struct program_space *pspace);
554 /* Version of the above suitable for use as a cleanup. */
555 extern void resume_section_map_updates_cleanup (void *arg);
557 extern void default_iterate_over_objfiles_in_search_order
558 (struct gdbarch *gdbarch,
559 iterate_over_objfiles_in_search_order_cb_ftype *cb,
560 void *cb_data, struct objfile *current_objfile);
563 /* Traverse all object files in the current program space.
564 ALL_OBJFILES_SAFE works even if you delete the objfile during the
567 /* Traverse all object files in program space SS. */
569 #define ALL_PSPACE_OBJFILES(ss, obj) \
570 for ((obj) = ss->objfiles; (obj) != NULL; (obj) = (obj)->next)
572 #define ALL_OBJFILES(obj) \
573 for ((obj) = current_program_space->objfiles; \
577 #define ALL_OBJFILES_SAFE(obj,nxt) \
578 for ((obj) = current_program_space->objfiles; \
579 (obj) != NULL? ((nxt)=(obj)->next,1) :0; \
582 /* Traverse all symtabs in one objfile. */
584 #define ALL_OBJFILE_FILETABS(objfile, cu, s) \
585 ALL_OBJFILE_COMPUNITS (objfile, cu) \
586 ALL_COMPUNIT_FILETABS (cu, s)
588 /* Traverse all compunits in one objfile. */
590 #define ALL_OBJFILE_COMPUNITS(objfile, cu) \
591 for ((cu) = (objfile) -> compunit_symtabs; (cu) != NULL; (cu) = (cu) -> next)
593 /* Traverse all minimal symbols in one objfile. */
595 #define ALL_OBJFILE_MSYMBOLS(objfile, m) \
596 for ((m) = (objfile)->per_bfd->msymbols; \
597 MSYMBOL_LINKAGE_NAME (m) != NULL; \
600 /* Traverse all symtabs in all objfiles in the current symbol
603 #define ALL_FILETABS(objfile, ps, s) \
604 ALL_OBJFILES (objfile) \
605 ALL_OBJFILE_FILETABS (objfile, ps, s)
607 /* Traverse all compunits in all objfiles in the current program space. */
609 #define ALL_COMPUNITS(objfile, cu) \
610 ALL_OBJFILES (objfile) \
611 ALL_OBJFILE_COMPUNITS (objfile, cu)
613 /* Traverse all minimal symbols in all objfiles in the current symbol
616 #define ALL_MSYMBOLS(objfile, m) \
617 ALL_OBJFILES (objfile) \
618 ALL_OBJFILE_MSYMBOLS (objfile, m)
620 #define ALL_OBJFILE_OSECTIONS(objfile, osect) \
621 for (osect = objfile->sections; osect < objfile->sections_end; osect++) \
622 if (osect->the_bfd_section == NULL) \
628 /* Traverse all obj_sections in all objfiles in the current program
631 Note that this detects a "break" in the inner loop, and exits
632 immediately from the outer loop as well, thus, client code doesn't
633 need to know that this is implemented with a double for. The extra
634 hair is to make sure that a "break;" stops the outer loop iterating
635 as well, and both OBJFILE and OSECT are left unmodified:
637 - The outer loop learns about the inner loop's end condition, and
638 stops iterating if it detects the inner loop didn't reach its
639 end. In other words, the outer loop keeps going only if the
640 inner loop reached its end cleanly [(osect) ==
641 (objfile)->sections_end].
643 - OSECT is initialized in the outer loop initialization
644 expressions, such as if the inner loop has reached its end, so
645 the check mentioned above succeeds the first time.
647 - The trick to not clearing OBJFILE on a "break;" is, in the outer
648 loop's loop expression, advance OBJFILE, but iff the inner loop
649 reached its end. If not, there was a "break;", so leave OBJFILE
650 as is; the outer loop's conditional will break immediately as
651 well (as OSECT will be different from OBJFILE->sections_end). */
653 #define ALL_OBJSECTIONS(objfile, osect) \
654 for ((objfile) = current_program_space->objfiles, \
655 (objfile) != NULL ? ((osect) = (objfile)->sections_end) : 0; \
657 && (osect) == (objfile)->sections_end; \
658 ((osect) == (objfile)->sections_end \
659 ? ((objfile) = (objfile)->next, \
660 (objfile) != NULL ? (osect) = (objfile)->sections_end : 0) \
662 ALL_OBJFILE_OSECTIONS (objfile, osect)
664 #define SECT_OFF_DATA(objfile) \
665 ((objfile->sect_index_data == -1) \
666 ? (internal_error (__FILE__, __LINE__, \
667 _("sect_index_data not initialized")), -1) \
668 : objfile->sect_index_data)
670 #define SECT_OFF_RODATA(objfile) \
671 ((objfile->sect_index_rodata == -1) \
672 ? (internal_error (__FILE__, __LINE__, \
673 _("sect_index_rodata not initialized")), -1) \
674 : objfile->sect_index_rodata)
676 #define SECT_OFF_TEXT(objfile) \
677 ((objfile->sect_index_text == -1) \
678 ? (internal_error (__FILE__, __LINE__, \
679 _("sect_index_text not initialized")), -1) \
680 : objfile->sect_index_text)
682 /* Sometimes the .bss section is missing from the objfile, so we don't
683 want to die here. Let the users of SECT_OFF_BSS deal with an
684 uninitialized section index. */
685 #define SECT_OFF_BSS(objfile) (objfile)->sect_index_bss
687 /* Answer whether there is more than one object file loaded. */
689 #define MULTI_OBJFILE_P() (object_files && object_files->next)
691 /* Reset the per-BFD storage area on OBJ. */
693 void set_objfile_per_bfd (struct objfile *obj);
695 /* Return canonical name for OBJFILE.
696 This is the real file name if the file has been opened.
697 Otherwise it is the original name supplied by the user. */
699 const char *objfile_name (const struct objfile *objfile);
701 /* Return the (real) file name of OBJFILE if the file has been opened,
702 otherwise return NULL. */
704 const char *objfile_filename (const struct objfile *objfile);
706 /* Return the name to print for OBJFILE in debugging messages. */
708 extern const char *objfile_debug_name (const struct objfile *objfile);
710 /* Return the name of the file format of OBJFILE if the file has been opened,
711 otherwise return NULL. */
713 const char *objfile_flavour_name (struct objfile *objfile);
715 /* Set the objfile's notion of the "main" name and language. */
717 extern void set_objfile_main_name (struct objfile *objfile,
718 const char *name, enum language lang);
720 extern void objfile_register_static_link
721 (struct objfile *objfile,
722 const struct block *block,
723 const struct dynamic_prop *static_link);
725 extern const struct dynamic_prop *objfile_lookup_static_link
726 (struct objfile *objfile, const struct block *block);
728 #endif /* !defined (OBJFILES_H) */