1 /* Definitions for symbol file management in GDB.
3 Copyright (C) 1992-2019 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"
32 #include "common/next-iterator.h"
33 #include "common/safe-iterator.h"
38 struct partial_symbol;
40 /* This structure maintains information on a per-objfile basis about the
41 "entry point" of the objfile, and the scope within which the entry point
42 exists. It is possible that gdb will see more than one objfile that is
43 executable, each with its own entry point.
45 For example, for dynamically linked executables in SVR4, the dynamic linker
46 code is contained within the shared C library, which is actually executable
47 and is run by the kernel first when an exec is done of a user executable
48 that is dynamically linked. The dynamic linker within the shared C library
49 then maps in the various program segments in the user executable and jumps
50 to the user executable's recorded entry point, as if the call had been made
51 directly by the kernel.
53 The traditional gdb method of using this info was to use the
54 recorded entry point to set the entry-file's lowpc and highpc from
55 the debugging information, where these values are the starting
56 address (inclusive) and ending address (exclusive) of the
57 instruction space in the executable which correspond to the
58 "startup file", i.e. crt0.o in most cases. This file is assumed to
59 be a startup file and frames with pc's inside it are treated as
60 nonexistent. Setting these variables is necessary so that
61 backtraces do not fly off the bottom of the stack.
63 NOTE: cagney/2003-09-09: It turns out that this "traditional"
64 method doesn't work. Corinna writes: ``It turns out that the call
65 to test for "inside entry file" destroys a meaningful backtrace
66 under some conditions. E.g. the backtrace tests in the asm-source
67 testcase are broken for some targets. In this test the functions
68 are all implemented as part of one file and the testcase is not
69 necessarily linked with a start file (depending on the target).
70 What happens is, that the first frame is printed normaly and
71 following frames are treated as being inside the enttry file then.
72 This way, only the #0 frame is printed in the backtrace output.''
73 Ref "frame.c" "NOTE: vinschen/2003-04-01".
75 Gdb also supports an alternate method to avoid running off the bottom
78 There are two frames that are "special", the frame for the function
79 containing the process entry point, since it has no predecessor frame,
80 and the frame for the function containing the user code entry point
81 (the main() function), since all the predecessor frames are for the
82 process startup code. Since we have no guarantee that the linked
83 in startup modules have any debugging information that gdb can use,
84 we need to avoid following frame pointers back into frames that might
85 have been built in the startup code, as we might get hopelessly
86 confused. However, we almost always have debugging information
89 These variables are used to save the range of PC values which are
90 valid within the main() function and within the function containing
91 the process entry point. If we always consider the frame for
92 main() as the outermost frame when debugging user code, and the
93 frame for the process entry point function as the outermost frame
94 when debugging startup code, then all we have to do is have
95 DEPRECATED_FRAME_CHAIN_VALID return false whenever a frame's
96 current PC is within the range specified by these variables. In
97 essence, we set "ceilings" in the frame chain beyond which we will
98 not proceed when following the frame chain back up the stack.
100 A nice side effect is that we can still debug startup code without
101 running off the end of the frame chain, assuming that we have usable
102 debugging information in the startup modules, and if we choose to not
103 use the block at main, or can't find it for some reason, everything
104 still works as before. And if we have no startup code debugging
105 information but we do have usable information for main(), backtraces
106 from user code don't go wandering off into the startup code. */
110 /* The unrelocated value we should use for this objfile entry point. */
111 CORE_ADDR entry_point;
113 /* The index of the section in which the entry point appears. */
114 int the_bfd_section_index;
116 /* Set to 1 iff ENTRY_POINT contains a valid value. */
117 unsigned entry_point_p : 1;
119 /* Set to 1 iff this object was initialized. */
120 unsigned initialized : 1;
123 /* Sections in an objfile. The section offsets are stored in the
128 /* BFD section pointer */
129 struct bfd_section *the_bfd_section;
131 /* Objfile this section is part of. */
132 struct objfile *objfile;
134 /* True if this "overlay section" is mapped into an "overlay region". */
138 /* Relocation offset applied to S. */
139 #define obj_section_offset(s) \
140 (((s)->objfile->section_offsets)->offsets[gdb_bfd_section_index ((s)->objfile->obfd, (s)->the_bfd_section)])
142 /* The memory address of section S (vma + offset). */
143 #define obj_section_addr(s) \
144 (bfd_get_section_vma ((s)->objfile->obfd, s->the_bfd_section) \
145 + obj_section_offset (s))
147 /* The one-passed-the-end memory address of section S
148 (vma + size + offset). */
149 #define obj_section_endaddr(s) \
150 (bfd_get_section_vma ((s)->objfile->obfd, s->the_bfd_section) \
151 + bfd_get_section_size ((s)->the_bfd_section) \
152 + obj_section_offset (s))
154 /* The "objstats" structure provides a place for gdb to record some
155 interesting information about its internal state at runtime, on a
156 per objfile basis, such as information about the number of symbols
157 read, size of string table (if any), etc. */
161 /* Number of partial symbols read. */
164 /* Number of full symbols read. */
167 /* Number of ".stabs" read (if applicable). */
170 /* Number of types. */
173 /* Size of stringtable, (if applicable). */
177 #define OBJSTAT(objfile, expr) (objfile -> stats.expr)
178 #define OBJSTATS struct objstats stats
179 extern void print_objfile_statistics (void);
180 extern void print_symbol_bcache_statistics (void);
182 /* Number of entries in the minimal symbol hash table. */
183 #define MINIMAL_SYMBOL_HASH_SIZE 2039
185 /* Some objfile data is hung off the BFD. This enables sharing of the
186 data across all objfiles using the BFD. The data is stored in an
187 instance of this structure, and associated with the BFD using the
190 struct objfile_per_bfd_storage
192 objfile_per_bfd_storage ()
193 : minsyms_read (false)
196 /* The storage has an obstack of its own. */
198 auto_obstack storage_obstack;
200 /* Byte cache for file names. */
202 bcache *filename_cache = NULL;
204 /* Byte cache for macros. */
206 bcache *macro_cache = NULL;
208 /* The gdbarch associated with the BFD. Note that this gdbarch is
209 determined solely from BFD information, without looking at target
210 information. The gdbarch determined from a running target may
211 differ from this e.g. with respect to register types and names. */
213 struct gdbarch *gdbarch = NULL;
215 /* Hash table for mapping symbol names to demangled names. Each
216 entry in the hash table is actually two consecutive strings,
217 both null-terminated; the first one is a mangled or linkage
218 name, and the second is the demangled name or just a zero byte
219 if the name doesn't demangle. */
221 htab *demangled_names_hash = NULL;
223 /* The per-objfile information about the entry point, the scope (file/func)
224 containing the entry point, and the scope of the user's main() func. */
228 /* The name and language of any "main" found in this objfile. The
229 name can be NULL, which means that the information was not
232 const char *name_of_main = NULL;
233 enum language language_of_main = language_unknown;
235 /* Each file contains a pointer to an array of minimal symbols for all
236 global symbols that are defined within the file. The array is
237 terminated by a "null symbol", one that has a NULL pointer for the
238 name and a zero value for the address. This makes it easy to walk
239 through the array when passed a pointer to somewhere in the middle
240 of it. There is also a count of the number of symbols, which does
241 not include the terminating null symbol. The array itself, as well
242 as all the data that it points to, should be allocated on the
243 objfile_obstack for this file. */
245 minimal_symbol *msymbols = NULL;
246 int minimal_symbol_count = 0;
248 /* The number of minimal symbols read, before any minimal symbol
249 de-duplication is applied. Note in particular that this has only
250 a passing relationship with the actual size of the table above;
251 use minimal_symbol_count if you need the true size. */
255 /* This is true if minimal symbols have already been read. Symbol
256 readers can use this to bypass minimal symbol reading. Also, the
257 minimal symbol table management code in minsyms.c uses this to
258 suppress new minimal symbols. You might think that MSYMBOLS or
259 MINIMAL_SYMBOL_COUNT could be used for this, but it is possible
260 for multiple readers to install minimal symbols into a given
263 bool minsyms_read : 1;
265 /* This is a hash table used to index the minimal symbols by name. */
267 minimal_symbol *msymbol_hash[MINIMAL_SYMBOL_HASH_SIZE] {};
269 /* This hash table is used to index the minimal symbols by their
272 minimal_symbol *msymbol_demangled_hash[MINIMAL_SYMBOL_HASH_SIZE] {};
274 /* All the different languages of symbols found in the demangled
275 hash table. A flat/vector-based map is more efficient than a map
276 or hash table here, since this will only usually contain zero or
278 std::vector<enum language> demangled_hash_languages;
281 /* Master structure for keeping track of each file from which
282 gdb reads symbols. There are several ways these get allocated: 1.
283 The main symbol file, symfile_objfile, set by the symbol-file command,
284 2. Additional symbol files added by the add-symbol-file command,
285 3. Shared library objfiles, added by ADD_SOLIB, 4. symbol files
286 for modules that were loaded when GDB attached to a remote system
287 (see remote-vx.c). */
291 objfile (bfd *, const char *, objfile_flags);
294 DISABLE_COPY_AND_ASSIGN (objfile);
296 /* Reset the storage for the partial symbol tables. */
298 void reset_psymtabs ()
300 psymbol_map.clear ();
301 partial_symtabs.reset (new psymtab_storage ());
305 /* All struct objfile's are chained together by their next pointers.
306 The program space field "objfiles" (frequently referenced via
307 the macro "object_files") points to the first link in this chain. */
309 struct objfile *next = nullptr;
311 /* The object file's original name as specified by the user,
312 made absolute, and tilde-expanded. However, it is not canonicalized
313 (i.e., it has not been passed through gdb_realpath).
314 This pointer is never NULL. This does not have to be freed; it is
315 guaranteed to have a lifetime at least as long as the objfile. */
317 char *original_name = nullptr;
319 CORE_ADDR addr_low = 0;
321 /* Some flag bits for this objfile. */
325 /* The program space associated with this objfile. */
327 struct program_space *pspace;
329 /* List of compunits.
330 These are used to do symbol lookups and file/line-number lookups. */
332 struct compunit_symtab *compunit_symtabs = nullptr;
334 /* The partial symbol tables. */
336 std::shared_ptr<psymtab_storage> partial_symtabs;
338 /* The object file's BFD. Can be null if the objfile contains only
339 minimal symbols, e.g. the run time common symbols for SunOS4. */
343 /* The per-BFD data. Note that this is treated specially if OBFD
346 struct objfile_per_bfd_storage *per_bfd = nullptr;
348 /* The modification timestamp of the object file, as of the last time
349 we read its symbols. */
353 /* Obstack to hold objects that should be freed when we load a new symbol
354 table from this object file. */
356 struct obstack objfile_obstack {};
358 /* Map symbol addresses to the partial symtab that defines the
359 object at that address. */
361 std::vector<std::pair<CORE_ADDR, partial_symtab *>> psymbol_map;
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 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 void free_all_objfiles (void);
484 extern void objfile_relocate (struct objfile *, const struct section_offsets *);
485 extern void objfile_rebase (struct objfile *, CORE_ADDR);
487 extern int objfile_has_partial_symbols (struct objfile *objfile);
489 extern int objfile_has_full_symbols (struct objfile *objfile);
491 extern int objfile_has_symbols (struct objfile *objfile);
493 extern int have_partial_symbols (void);
495 extern int have_full_symbols (void);
497 extern void objfile_set_sym_fns (struct objfile *objfile,
498 const struct sym_fns *sf);
500 extern void objfiles_changed (void);
502 extern int is_addr_in_objfile (CORE_ADDR addr, const struct objfile *objfile);
504 /* Return true if ADDRESS maps into one of the sections of a
505 OBJF_SHARED objfile of PSPACE and false otherwise. */
507 extern int shared_objfile_contains_address_p (struct program_space *pspace,
510 /* This operation deletes all objfile entries that represent solibs that
511 weren't explicitly loaded by the user, via e.g., the add-symbol-file
514 extern void objfile_purge_solibs (void);
516 /* Functions for dealing with the minimal symbol table, really a misc
517 address<->symbol mapping for things we don't have debug symbols for. */
519 extern int have_minimal_symbols (void);
521 extern struct obj_section *find_pc_section (CORE_ADDR pc);
523 /* Return non-zero if PC is in a section called NAME. */
524 extern int pc_in_section (CORE_ADDR, const char *);
526 /* Return non-zero if PC is in a SVR4-style procedure linkage table
530 in_plt_section (CORE_ADDR pc)
532 return pc_in_section (pc, ".plt");
535 /* Keep a registry of per-objfile data-pointers required by other GDB
537 DECLARE_REGISTRY(objfile);
539 /* In normal use, the section map will be rebuilt by find_pc_section
540 if objfiles have been added, removed or relocated since it was last
541 called. Calling inhibit_section_map_updates will inhibit this
542 behavior until the returned scoped_restore object is destroyed. If
543 you call inhibit_section_map_updates you must ensure that every
544 call to find_pc_section in the inhibited region relates to a
545 section that is already in the section map and has not since been
546 removed or relocated. */
547 extern scoped_restore_tmpl<int> inhibit_section_map_updates
548 (struct program_space *pspace);
550 extern void default_iterate_over_objfiles_in_search_order
551 (struct gdbarch *gdbarch,
552 iterate_over_objfiles_in_search_order_cb_ftype *cb,
553 void *cb_data, struct objfile *current_objfile);
556 /* An iterarable object that can be used to iterate over all
557 objfiles. The basic use is in a foreach, like:
559 for (objfile *objf : all_objfiles_safe (pspace)) { ... }
561 This variant uses a basic_safe_iterator so that objfiles can be
562 deleted during iteration. */
564 class all_objfiles_safe
565 : public next_adapter<struct objfile,
566 basic_safe_iterator<next_iterator<objfile>>>
570 explicit all_objfiles_safe (struct program_space *pspace)
571 : next_adapter<struct objfile,
572 basic_safe_iterator<next_iterator<objfile>>>
573 (pspace->objfiles_head)
578 /* A range adapter that makes it possible to iterate over all
579 compunits in one objfile. */
581 class objfile_compunits : public next_adapter<struct compunit_symtab>
585 explicit objfile_compunits (struct objfile *objfile)
586 : next_adapter<struct compunit_symtab> (objfile->compunit_symtabs)
591 /* A range adapter that makes it possible to iterate over all
592 minimal symbols of an objfile. */
594 class objfile_msymbols
598 explicit objfile_msymbols (struct objfile *objfile)
599 : m_objfile (objfile)
605 typedef iterator self_type;
606 typedef struct minimal_symbol *value_type;
607 typedef struct minimal_symbol *&reference;
608 typedef struct minimal_symbol **pointer;
609 typedef std::forward_iterator_tag iterator_category;
610 typedef int difference_type;
612 explicit iterator (struct objfile *objfile)
613 : m_msym (objfile->per_bfd->msymbols)
615 /* Make sure to properly handle the case where there are no
617 if (MSYMBOL_LINKAGE_NAME (m_msym) == nullptr)
626 value_type operator* () const
631 bool operator== (const self_type &other) const
633 return m_msym == other.m_msym;
636 bool operator!= (const self_type &other) const
638 return m_msym != other.m_msym;
641 self_type &operator++ ()
643 if (m_msym != nullptr)
646 if (MSYMBOL_LINKAGE_NAME (m_msym) == nullptr)
653 struct minimal_symbol *m_msym;
656 iterator begin () const
658 return iterator (m_objfile);
661 iterator end () const
668 struct objfile *m_objfile;
671 /* A range adapter that makes it possible to iterate over all
672 psymtabs in one objfile. */
674 class objfile_psymtabs : public next_adapter<struct partial_symtab>
678 explicit objfile_psymtabs (struct objfile *objfile)
679 : next_adapter<struct partial_symtab> (objfile->partial_symtabs->psymtabs)
684 #define ALL_OBJFILE_OSECTIONS(objfile, osect) \
685 for (osect = objfile->sections; osect < objfile->sections_end; osect++) \
686 if (osect->the_bfd_section == NULL) \
692 #define SECT_OFF_DATA(objfile) \
693 ((objfile->sect_index_data == -1) \
694 ? (internal_error (__FILE__, __LINE__, \
695 _("sect_index_data not initialized")), -1) \
696 : objfile->sect_index_data)
698 #define SECT_OFF_RODATA(objfile) \
699 ((objfile->sect_index_rodata == -1) \
700 ? (internal_error (__FILE__, __LINE__, \
701 _("sect_index_rodata not initialized")), -1) \
702 : objfile->sect_index_rodata)
704 #define SECT_OFF_TEXT(objfile) \
705 ((objfile->sect_index_text == -1) \
706 ? (internal_error (__FILE__, __LINE__, \
707 _("sect_index_text not initialized")), -1) \
708 : objfile->sect_index_text)
710 /* Sometimes the .bss section is missing from the objfile, so we don't
711 want to die here. Let the users of SECT_OFF_BSS deal with an
712 uninitialized section index. */
713 #define SECT_OFF_BSS(objfile) (objfile)->sect_index_bss
715 /* Answer whether there is more than one object file loaded. */
717 #define MULTI_OBJFILE_P() (object_files && object_files->next)
719 /* Reset the per-BFD storage area on OBJ. */
721 void set_objfile_per_bfd (struct objfile *obj);
723 /* Return canonical name for OBJFILE.
724 This is the real file name if the file has been opened.
725 Otherwise it is the original name supplied by the user. */
727 const char *objfile_name (const struct objfile *objfile);
729 /* Return the (real) file name of OBJFILE if the file has been opened,
730 otherwise return NULL. */
732 const char *objfile_filename (const struct objfile *objfile);
734 /* Return the name to print for OBJFILE in debugging messages. */
736 extern const char *objfile_debug_name (const struct objfile *objfile);
738 /* Return the name of the file format of OBJFILE if the file has been opened,
739 otherwise return NULL. */
741 const char *objfile_flavour_name (struct objfile *objfile);
743 /* Set the objfile's notion of the "main" name and language. */
745 extern void set_objfile_main_name (struct objfile *objfile,
746 const char *name, enum language lang);
748 extern void objfile_register_static_link
749 (struct objfile *objfile,
750 const struct block *block,
751 const struct dynamic_prop *static_link);
753 extern const struct dynamic_prop *objfile_lookup_static_link
754 (struct objfile *objfile, const struct block *block);
756 #endif /* !defined (OBJFILES_H) */