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"
33 #include "common/next-iterator.h"
34 #include "common/safe-iterator.h"
39 struct partial_symbol
;
41 /* This structure maintains information on a per-objfile basis about the
42 "entry point" of the objfile, and the scope within which the entry point
43 exists. It is possible that gdb will see more than one objfile that is
44 executable, each with its own entry point.
46 For example, for dynamically linked executables in SVR4, the dynamic linker
47 code is contained within the shared C library, which is actually executable
48 and is run by the kernel first when an exec is done of a user executable
49 that is dynamically linked. The dynamic linker within the shared C library
50 then maps in the various program segments in the user executable and jumps
51 to the user executable's recorded entry point, as if the call had been made
52 directly by the kernel.
54 The traditional gdb method of using this info was to use the
55 recorded entry point to set the entry-file's lowpc and highpc from
56 the debugging information, where these values are the starting
57 address (inclusive) and ending address (exclusive) of the
58 instruction space in the executable which correspond to the
59 "startup file", i.e. crt0.o in most cases. This file is assumed to
60 be a startup file and frames with pc's inside it are treated as
61 nonexistent. Setting these variables is necessary so that
62 backtraces do not fly off the bottom of the stack.
64 NOTE: cagney/2003-09-09: It turns out that this "traditional"
65 method doesn't work. Corinna writes: ``It turns out that the call
66 to test for "inside entry file" destroys a meaningful backtrace
67 under some conditions. E.g. the backtrace tests in the asm-source
68 testcase are broken for some targets. In this test the functions
69 are all implemented as part of one file and the testcase is not
70 necessarily linked with a start file (depending on the target).
71 What happens is, that the first frame is printed normaly and
72 following frames are treated as being inside the enttry file then.
73 This way, only the #0 frame is printed in the backtrace output.''
74 Ref "frame.c" "NOTE: vinschen/2003-04-01".
76 Gdb also supports an alternate method to avoid running off the bottom
79 There are two frames that are "special", the frame for the function
80 containing the process entry point, since it has no predecessor frame,
81 and the frame for the function containing the user code entry point
82 (the main() function), since all the predecessor frames are for the
83 process startup code. Since we have no guarantee that the linked
84 in startup modules have any debugging information that gdb can use,
85 we need to avoid following frame pointers back into frames that might
86 have been built in the startup code, as we might get hopelessly
87 confused. However, we almost always have debugging information
90 These variables are used to save the range of PC values which are
91 valid within the main() function and within the function containing
92 the process entry point. If we always consider the frame for
93 main() as the outermost frame when debugging user code, and the
94 frame for the process entry point function as the outermost frame
95 when debugging startup code, then all we have to do is have
96 DEPRECATED_FRAME_CHAIN_VALID return false whenever a frame's
97 current PC is within the range specified by these variables. In
98 essence, we set "ceilings" in the frame chain beyond which we will
99 not proceed when following the frame chain back up the stack.
101 A nice side effect is that we can still debug startup code without
102 running off the end of the frame chain, assuming that we have usable
103 debugging information in the startup modules, and if we choose to not
104 use the block at main, or can't find it for some reason, everything
105 still works as before. And if we have no startup code debugging
106 information but we do have usable information for main(), backtraces
107 from user code don't go wandering off into the startup code. */
111 /* The unrelocated value we should use for this objfile entry point. */
112 CORE_ADDR entry_point
;
114 /* The index of the section in which the entry point appears. */
115 int the_bfd_section_index
;
117 /* Set to 1 iff ENTRY_POINT contains a valid value. */
118 unsigned entry_point_p
: 1;
120 /* Set to 1 iff this object was initialized. */
121 unsigned initialized
: 1;
124 /* Sections in an objfile. The section offsets are stored in the
129 /* BFD section pointer */
130 struct bfd_section
*the_bfd_section
;
132 /* Objfile this section is part of. */
133 struct objfile
*objfile
;
135 /* True if this "overlay section" is mapped into an "overlay region". */
139 /* Relocation offset applied to S. */
140 #define obj_section_offset(s) \
141 (((s)->objfile->section_offsets)->offsets[gdb_bfd_section_index ((s)->objfile->obfd, (s)->the_bfd_section)])
143 /* The memory address of section S (vma + offset). */
144 #define obj_section_addr(s) \
145 (bfd_get_section_vma ((s)->objfile->obfd, s->the_bfd_section) \
146 + obj_section_offset (s))
148 /* The one-passed-the-end memory address of section S
149 (vma + size + offset). */
150 #define obj_section_endaddr(s) \
151 (bfd_get_section_vma ((s)->objfile->obfd, s->the_bfd_section) \
152 + bfd_get_section_size ((s)->the_bfd_section) \
153 + obj_section_offset (s))
155 /* The "objstats" structure provides a place for gdb to record some
156 interesting information about its internal state at runtime, on a
157 per objfile basis, such as information about the number of symbols
158 read, size of string table (if any), etc. */
162 /* Number of partial symbols read. */
165 /* Number of full symbols read. */
168 /* Number of ".stabs" read (if applicable). */
171 /* Number of types. */
174 /* Size of stringtable, (if applicable). */
178 #define OBJSTAT(objfile, expr) (objfile -> stats.expr)
179 #define OBJSTATS struct objstats stats
180 extern void print_objfile_statistics (void);
181 extern void print_symbol_bcache_statistics (void);
183 /* Number of entries in the minimal symbol hash table. */
184 #define MINIMAL_SYMBOL_HASH_SIZE 2039
186 /* An iterator for minimal symbols. */
188 struct minimal_symbol_iterator
190 typedef minimal_symbol_iterator self_type
;
191 typedef struct minimal_symbol
*value_type
;
192 typedef struct minimal_symbol
*&reference
;
193 typedef struct minimal_symbol
**pointer
;
194 typedef std::forward_iterator_tag iterator_category
;
195 typedef int difference_type
;
197 explicit minimal_symbol_iterator (struct minimal_symbol
*msym
)
202 value_type
operator* () const
207 bool operator== (const self_type
&other
) const
209 return m_msym
== other
.m_msym
;
212 bool operator!= (const self_type
&other
) const
214 return m_msym
!= other
.m_msym
;
217 self_type
&operator++ ()
224 struct minimal_symbol
*m_msym
;
227 /* Some objfile data is hung off the BFD. This enables sharing of the
228 data across all objfiles using the BFD. The data is stored in an
229 instance of this structure, and associated with the BFD using the
232 struct objfile_per_bfd_storage
234 objfile_per_bfd_storage ()
235 : minsyms_read (false)
238 ~objfile_per_bfd_storage ();
240 /* The storage has an obstack of its own. */
242 auto_obstack storage_obstack
;
244 /* Byte cache for file names. */
246 struct bcache filename_cache
;
248 /* Byte cache for macros. */
250 struct bcache macro_cache
;
252 /* The gdbarch associated with the BFD. Note that this gdbarch is
253 determined solely from BFD information, without looking at target
254 information. The gdbarch determined from a running target may
255 differ from this e.g. with respect to register types and names. */
257 struct gdbarch
*gdbarch
= NULL
;
259 /* Hash table for mapping symbol names to demangled names. Each
260 entry in the hash table is actually two consecutive strings,
261 both null-terminated; the first one is a mangled or linkage
262 name, and the second is the demangled name or just a zero byte
263 if the name doesn't demangle. */
265 htab_up demangled_names_hash
;
267 /* The per-objfile information about the entry point, the scope (file/func)
268 containing the entry point, and the scope of the user's main() func. */
272 /* The name and language of any "main" found in this objfile. The
273 name can be NULL, which means that the information was not
276 const char *name_of_main
= NULL
;
277 enum language language_of_main
= language_unknown
;
279 /* Each file contains a pointer to an array of minimal symbols for all
280 global symbols that are defined within the file. The array is
281 terminated by a "null symbol", one that has a NULL pointer for the
282 name and a zero value for the address. This makes it easy to walk
283 through the array when passed a pointer to somewhere in the middle
284 of it. There is also a count of the number of symbols, which does
285 not include the terminating null symbol. The array itself, as well
286 as all the data that it points to, should be allocated on the
287 objfile_obstack for this file. */
289 minimal_symbol
*msymbols
= NULL
;
290 int minimal_symbol_count
= 0;
292 /* The number of minimal symbols read, before any minimal symbol
293 de-duplication is applied. Note in particular that this has only
294 a passing relationship with the actual size of the table above;
295 use minimal_symbol_count if you need the true size. */
299 /* This is true if minimal symbols have already been read. Symbol
300 readers can use this to bypass minimal symbol reading. Also, the
301 minimal symbol table management code in minsyms.c uses this to
302 suppress new minimal symbols. You might think that MSYMBOLS or
303 MINIMAL_SYMBOL_COUNT could be used for this, but it is possible
304 for multiple readers to install minimal symbols into a given
307 bool minsyms_read
: 1;
309 /* This is a hash table used to index the minimal symbols by name. */
311 minimal_symbol
*msymbol_hash
[MINIMAL_SYMBOL_HASH_SIZE
] {};
313 /* This hash table is used to index the minimal symbols by their
316 minimal_symbol
*msymbol_demangled_hash
[MINIMAL_SYMBOL_HASH_SIZE
] {};
318 /* All the different languages of symbols found in the demangled
320 std::bitset
<nr_languages
> demangled_hash_languages
;
323 /* Master structure for keeping track of each file from which
324 gdb reads symbols. There are several ways these get allocated: 1.
325 The main symbol file, symfile_objfile, set by the symbol-file command,
326 2. Additional symbol files added by the add-symbol-file command,
327 3. Shared library objfiles, added by ADD_SOLIB, 4. symbol files
328 for modules that were loaded when GDB attached to a remote system
329 (see remote-vx.c). */
333 objfile (bfd
*, const char *, objfile_flags
);
336 DISABLE_COPY_AND_ASSIGN (objfile
);
338 /* A range adapter that makes it possible to iterate over all
339 psymtabs in one objfile. */
341 psymtab_storage::partial_symtab_range
psymtabs ()
343 return partial_symtabs
->range ();
346 /* Reset the storage for the partial symbol tables. */
348 void reset_psymtabs ()
350 psymbol_map
.clear ();
351 partial_symtabs
.reset (new psymtab_storage ());
354 typedef next_adapter
<struct compunit_symtab
> compunits_range
;
356 /* A range adapter that makes it possible to iterate over all
357 compunits in one objfile. */
359 compunits_range
compunits ()
361 return compunits_range (compunit_symtabs
);
364 /* A range adapter that makes it possible to iterate over all
365 minimal symbols of an objfile. */
371 explicit msymbols_range (struct objfile
*objfile
)
372 : m_objfile (objfile
)
376 minimal_symbol_iterator
begin () const
378 return minimal_symbol_iterator (m_objfile
->per_bfd
->msymbols
);
381 minimal_symbol_iterator
end () const
383 return minimal_symbol_iterator
384 (m_objfile
->per_bfd
->msymbols
385 + m_objfile
->per_bfd
->minimal_symbol_count
);
390 struct objfile
*m_objfile
;
393 /* Return a range adapter for iterating over all minimal
396 msymbols_range
msymbols ()
398 return msymbols_range (this);
402 /* All struct objfile's are chained together by their next pointers.
403 The program space field "objfiles" (frequently referenced via
404 the macro "object_files") points to the first link in this chain. */
406 struct objfile
*next
= nullptr;
408 /* The object file's original name as specified by the user,
409 made absolute, and tilde-expanded. However, it is not canonicalized
410 (i.e., it has not been passed through gdb_realpath).
411 This pointer is never NULL. This does not have to be freed; it is
412 guaranteed to have a lifetime at least as long as the objfile. */
414 char *original_name
= nullptr;
416 CORE_ADDR addr_low
= 0;
418 /* Some flag bits for this objfile. */
422 /* The program space associated with this objfile. */
424 struct program_space
*pspace
;
426 /* List of compunits.
427 These are used to do symbol lookups and file/line-number lookups. */
429 struct compunit_symtab
*compunit_symtabs
= nullptr;
431 /* The partial symbol tables. */
433 std::shared_ptr
<psymtab_storage
> partial_symtabs
;
435 /* The object file's BFD. Can be null if the objfile contains only
436 minimal symbols, e.g. the run time common symbols for SunOS4. */
440 /* The per-BFD data. Note that this is treated specially if OBFD
443 struct objfile_per_bfd_storage
*per_bfd
= nullptr;
445 /* The modification timestamp of the object file, as of the last time
446 we read its symbols. */
450 /* Obstack to hold objects that should be freed when we load a new symbol
451 table from this object file. */
453 struct obstack objfile_obstack
{};
455 /* Map symbol addresses to the partial symtab that defines the
456 object at that address. */
458 std::vector
<std::pair
<CORE_ADDR
, partial_symtab
*>> psymbol_map
;
460 /* Structure which keeps track of functions that manipulate objfile's
461 of the same type as this objfile. I.e. the function to read partial
462 symbols for example. Note that this structure is in statically
463 allocated memory, and is shared by all objfiles that use the
464 object module reader of this type. */
466 const struct sym_fns
*sf
= nullptr;
468 /* Per objfile data-pointers required by other GDB modules. */
472 /* Set of relocation offsets to apply to each section.
473 The table is indexed by the_bfd_section->index, thus it is generally
474 as large as the number of sections in the binary.
475 The table is stored on the objfile_obstack.
477 These offsets indicate that all symbols (including partial and
478 minimal symbols) which have been read have been relocated by this
479 much. Symbols which are yet to be read need to be relocated by it. */
481 struct section_offsets
*section_offsets
= nullptr;
482 int num_sections
= 0;
484 /* Indexes in the section_offsets array. These are initialized by the
485 *_symfile_offsets() family of functions (som_symfile_offsets,
486 xcoff_symfile_offsets, default_symfile_offsets). In theory they
487 should correspond to the section indexes used by bfd for the
488 current objfile. The exception to this for the time being is the
491 These are initialized to -1 so that we can later detect if they
492 are used w/o being properly assigned to. */
494 int sect_index_text
= -1;
495 int sect_index_data
= -1;
496 int sect_index_bss
= -1;
497 int sect_index_rodata
= -1;
499 /* These pointers are used to locate the section table, which
500 among other things, is used to map pc addresses into sections.
501 SECTIONS points to the first entry in the table, and
502 SECTIONS_END points to the first location past the last entry
503 in the table. The table is stored on the objfile_obstack. The
504 sections are indexed by the BFD section index; but the
505 structure data is only valid for certain sections
506 (e.g. non-empty, SEC_ALLOC). */
508 struct obj_section
*sections
= nullptr;
509 struct obj_section
*sections_end
= nullptr;
511 /* GDB allows to have debug symbols in separate object files. This is
512 used by .gnu_debuglink, ELF build id note and Mach-O OSO.
513 Although this is a tree structure, GDB only support one level
514 (ie a separate debug for a separate debug is not supported). Note that
515 separate debug object are in the main chain and therefore will be
516 visited by objfiles & co iterators. Separate debug objfile always
517 has a non-nul separate_debug_objfile_backlink. */
519 /* Link to the first separate debug object, if any. */
521 struct objfile
*separate_debug_objfile
= nullptr;
523 /* If this is a separate debug object, this is used as a link to the
524 actual executable objfile. */
526 struct objfile
*separate_debug_objfile_backlink
= nullptr;
528 /* If this is a separate debug object, this is a link to the next one
529 for the same executable objfile. */
531 struct objfile
*separate_debug_objfile_link
= nullptr;
533 /* Place to stash various statistics about this objfile. */
537 /* A linked list of symbols created when reading template types or
538 function templates. These symbols are not stored in any symbol
539 table, so we have to keep them here to relocate them
542 struct symbol
*template_symbols
= nullptr;
544 /* Associate a static link (struct dynamic_prop *) to all blocks (struct
545 block *) that have one.
547 In the context of nested functions (available in Pascal, Ada and GNU C,
548 for instance), a static link (as in DWARF's DW_AT_static_link attribute)
549 for a function is a way to get the frame corresponding to the enclosing
552 Very few blocks have a static link, so it's more memory efficient to
553 store these here rather than in struct block. Static links must be
554 allocated on the objfile's obstack. */
555 htab_t static_links
{};
558 /* Declarations for functions defined in objfiles.c */
560 extern struct gdbarch
*get_objfile_arch (const struct objfile
*);
562 extern int entry_point_address_query (CORE_ADDR
*entry_p
);
564 extern CORE_ADDR
entry_point_address (void);
566 extern void build_objfile_section_table (struct objfile
*);
568 extern struct objfile
*objfile_separate_debug_iterate (const struct objfile
*,
569 const struct objfile
*);
571 extern void put_objfile_before (struct objfile
*, struct objfile
*);
573 extern void add_separate_debug_objfile (struct objfile
*, struct objfile
*);
575 extern void unlink_objfile (struct objfile
*);
577 extern void free_objfile_separate_debug (struct objfile
*);
579 extern void free_all_objfiles (void);
581 extern void objfile_relocate (struct objfile
*, const struct section_offsets
*);
582 extern void objfile_rebase (struct objfile
*, CORE_ADDR
);
584 extern int objfile_has_partial_symbols (struct objfile
*objfile
);
586 extern int objfile_has_full_symbols (struct objfile
*objfile
);
588 extern int objfile_has_symbols (struct objfile
*objfile
);
590 extern int have_partial_symbols (void);
592 extern int have_full_symbols (void);
594 extern void objfile_set_sym_fns (struct objfile
*objfile
,
595 const struct sym_fns
*sf
);
597 extern void objfiles_changed (void);
599 extern int is_addr_in_objfile (CORE_ADDR addr
, const struct objfile
*objfile
);
601 /* Return true if ADDRESS maps into one of the sections of a
602 OBJF_SHARED objfile of PSPACE and false otherwise. */
604 extern int shared_objfile_contains_address_p (struct program_space
*pspace
,
607 /* This operation deletes all objfile entries that represent solibs that
608 weren't explicitly loaded by the user, via e.g., the add-symbol-file
611 extern void objfile_purge_solibs (void);
613 /* Functions for dealing with the minimal symbol table, really a misc
614 address<->symbol mapping for things we don't have debug symbols for. */
616 extern int have_minimal_symbols (void);
618 extern struct obj_section
*find_pc_section (CORE_ADDR pc
);
620 /* Return non-zero if PC is in a section called NAME. */
621 extern int pc_in_section (CORE_ADDR
, const char *);
623 /* Return non-zero if PC is in a SVR4-style procedure linkage table
627 in_plt_section (CORE_ADDR pc
)
629 return pc_in_section (pc
, ".plt");
632 /* Keep a registry of per-objfile data-pointers required by other GDB
634 DECLARE_REGISTRY(objfile
);
636 /* In normal use, the section map will be rebuilt by find_pc_section
637 if objfiles have been added, removed or relocated since it was last
638 called. Calling inhibit_section_map_updates will inhibit this
639 behavior until the returned scoped_restore object is destroyed. If
640 you call inhibit_section_map_updates you must ensure that every
641 call to find_pc_section in the inhibited region relates to a
642 section that is already in the section map and has not since been
643 removed or relocated. */
644 extern scoped_restore_tmpl
<int> inhibit_section_map_updates
645 (struct program_space
*pspace
);
647 extern void default_iterate_over_objfiles_in_search_order
648 (struct gdbarch
*gdbarch
,
649 iterate_over_objfiles_in_search_order_cb_ftype
*cb
,
650 void *cb_data
, struct objfile
*current_objfile
);
653 #define ALL_OBJFILE_OSECTIONS(objfile, osect) \
654 for (osect = objfile->sections; osect < objfile->sections_end; osect++) \
655 if (osect->the_bfd_section == NULL) \
661 #define SECT_OFF_DATA(objfile) \
662 ((objfile->sect_index_data == -1) \
663 ? (internal_error (__FILE__, __LINE__, \
664 _("sect_index_data not initialized")), -1) \
665 : objfile->sect_index_data)
667 #define SECT_OFF_RODATA(objfile) \
668 ((objfile->sect_index_rodata == -1) \
669 ? (internal_error (__FILE__, __LINE__, \
670 _("sect_index_rodata not initialized")), -1) \
671 : objfile->sect_index_rodata)
673 #define SECT_OFF_TEXT(objfile) \
674 ((objfile->sect_index_text == -1) \
675 ? (internal_error (__FILE__, __LINE__, \
676 _("sect_index_text not initialized")), -1) \
677 : objfile->sect_index_text)
679 /* Sometimes the .bss section is missing from the objfile, so we don't
680 want to die here. Let the users of SECT_OFF_BSS deal with an
681 uninitialized section index. */
682 #define SECT_OFF_BSS(objfile) (objfile)->sect_index_bss
684 /* Answer whether there is more than one object file loaded. */
686 #define MULTI_OBJFILE_P() (object_files && object_files->next)
688 /* Reset the per-BFD storage area on OBJ. */
690 void set_objfile_per_bfd (struct objfile
*obj
);
692 /* Return canonical name for OBJFILE.
693 This is the real file name if the file has been opened.
694 Otherwise it is the original name supplied by the user. */
696 const char *objfile_name (const struct objfile
*objfile
);
698 /* Return the (real) file name of OBJFILE if the file has been opened,
699 otherwise return NULL. */
701 const char *objfile_filename (const struct objfile
*objfile
);
703 /* Return the name to print for OBJFILE in debugging messages. */
705 extern const char *objfile_debug_name (const struct objfile
*objfile
);
707 /* Return the name of the file format of OBJFILE if the file has been opened,
708 otherwise return NULL. */
710 const char *objfile_flavour_name (struct objfile
*objfile
);
712 /* Set the objfile's notion of the "main" name and language. */
714 extern void set_objfile_main_name (struct objfile
*objfile
,
715 const char *name
, enum language lang
);
717 extern void objfile_register_static_link
718 (struct objfile
*objfile
,
719 const struct block
*block
,
720 const struct dynamic_prop
*static_link
);
722 extern const struct dynamic_prop
*objfile_lookup_static_link
723 (struct objfile
*objfile
, const struct block
*block
);
725 #endif /* !defined (OBJFILES_H) */