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 "gdbsupport/next-iterator.h"
34 #include "gdbsupport/safe-iterator.h"
40 struct partial_symbol
;
42 /* This structure maintains information on a per-objfile basis about the
43 "entry point" of the objfile, and the scope within which the entry point
44 exists. It is possible that gdb will see more than one objfile that is
45 executable, each with its own entry point.
47 For example, for dynamically linked executables in SVR4, the dynamic linker
48 code is contained within the shared C library, which is actually executable
49 and is run by the kernel first when an exec is done of a user executable
50 that is dynamically linked. The dynamic linker within the shared C library
51 then maps in the various program segments in the user executable and jumps
52 to the user executable's recorded entry point, as if the call had been made
53 directly by the kernel.
55 The traditional gdb method of using this info was to use the
56 recorded entry point to set the entry-file's lowpc and highpc from
57 the debugging information, where these values are the starting
58 address (inclusive) and ending address (exclusive) of the
59 instruction space in the executable which correspond to the
60 "startup file", i.e. crt0.o in most cases. This file is assumed to
61 be a startup file and frames with pc's inside it are treated as
62 nonexistent. Setting these variables is necessary so that
63 backtraces do not fly off the bottom of the stack.
65 NOTE: cagney/2003-09-09: It turns out that this "traditional"
66 method doesn't work. Corinna writes: ``It turns out that the call
67 to test for "inside entry file" destroys a meaningful backtrace
68 under some conditions. E.g. the backtrace tests in the asm-source
69 testcase are broken for some targets. In this test the functions
70 are all implemented as part of one file and the testcase is not
71 necessarily linked with a start file (depending on the target).
72 What happens is, that the first frame is printed normally and
73 following frames are treated as being inside the entry file then.
74 This way, only the #0 frame is printed in the backtrace output.''
75 Ref "frame.c" "NOTE: vinschen/2003-04-01".
77 Gdb also supports an alternate method to avoid running off the bottom
80 There are two frames that are "special", the frame for the function
81 containing the process entry point, since it has no predecessor frame,
82 and the frame for the function containing the user code entry point
83 (the main() function), since all the predecessor frames are for the
84 process startup code. Since we have no guarantee that the linked
85 in startup modules have any debugging information that gdb can use,
86 we need to avoid following frame pointers back into frames that might
87 have been built in the startup code, as we might get hopelessly
88 confused. However, we almost always have debugging information
91 These variables are used to save the range of PC values which are
92 valid within the main() function and within the function containing
93 the process entry point. If we always consider the frame for
94 main() as the outermost frame when debugging user code, and the
95 frame for the process entry point function as the outermost frame
96 when debugging startup code, then all we have to do is have
97 DEPRECATED_FRAME_CHAIN_VALID return false whenever a frame's
98 current PC is within the range specified by these variables. In
99 essence, we set "ceilings" in the frame chain beyond which we will
100 not proceed when following the frame chain back up the stack.
102 A nice side effect is that we can still debug startup code without
103 running off the end of the frame chain, assuming that we have usable
104 debugging information in the startup modules, and if we choose to not
105 use the block at main, or can't find it for some reason, everything
106 still works as before. And if we have no startup code debugging
107 information but we do have usable information for main(), backtraces
108 from user code don't go wandering off into the startup code. */
112 /* The unrelocated value we should use for this objfile entry point. */
113 CORE_ADDR entry_point
;
115 /* The index of the section in which the entry point appears. */
116 int the_bfd_section_index
;
118 /* Set to 1 iff ENTRY_POINT contains a valid value. */
119 unsigned entry_point_p
: 1;
121 /* Set to 1 iff this object was initialized. */
122 unsigned initialized
: 1;
125 /* Sections in an objfile. The section offsets are stored in the
130 /* BFD section pointer */
131 struct bfd_section
*the_bfd_section
;
133 /* Objfile this section is part of. */
134 struct objfile
*objfile
;
136 /* True if this "overlay section" is mapped into an "overlay region". */
140 /* Relocation offset applied to S. */
141 #define obj_section_offset(s) \
142 (((s)->objfile->section_offsets)->offsets[gdb_bfd_section_index ((s)->objfile->obfd, (s)->the_bfd_section)])
144 /* The memory address of section S (vma + offset). */
145 #define obj_section_addr(s) \
146 (bfd_section_vma (s->the_bfd_section) \
147 + obj_section_offset (s))
149 /* The one-passed-the-end memory address of section S
150 (vma + size + offset). */
151 #define obj_section_endaddr(s) \
152 (bfd_section_vma (s->the_bfd_section) \
153 + bfd_section_size ((s)->the_bfd_section) \
154 + obj_section_offset (s))
156 /* The "objstats" structure provides a place for gdb to record some
157 interesting information about its internal state at runtime, on a
158 per objfile basis, such as information about the number of symbols
159 read, size of string table (if any), etc. */
163 /* Number of partial symbols read. */
166 /* Number of full symbols read. */
169 /* Number of ".stabs" read (if applicable). */
172 /* Number of types. */
175 /* Size of stringtable, (if applicable). */
179 #define OBJSTAT(objfile, expr) (objfile -> stats.expr)
180 #define OBJSTATS struct objstats stats
181 extern void print_objfile_statistics (void);
182 extern void print_symbol_bcache_statistics (void);
184 /* Number of entries in the minimal symbol hash table. */
185 #define MINIMAL_SYMBOL_HASH_SIZE 2039
187 /* An iterator for minimal symbols. */
189 struct minimal_symbol_iterator
191 typedef minimal_symbol_iterator self_type
;
192 typedef struct minimal_symbol
*value_type
;
193 typedef struct minimal_symbol
*&reference
;
194 typedef struct minimal_symbol
**pointer
;
195 typedef std::forward_iterator_tag iterator_category
;
196 typedef int difference_type
;
198 explicit minimal_symbol_iterator (struct minimal_symbol
*msym
)
203 value_type
operator* () const
208 bool operator== (const self_type
&other
) const
210 return m_msym
== other
.m_msym
;
213 bool operator!= (const self_type
&other
) const
215 return m_msym
!= other
.m_msym
;
218 self_type
&operator++ ()
225 struct minimal_symbol
*m_msym
;
228 /* Some objfile data is hung off the BFD. This enables sharing of the
229 data across all objfiles using the BFD. The data is stored in an
230 instance of this structure, and associated with the BFD using the
233 struct objfile_per_bfd_storage
235 objfile_per_bfd_storage ()
236 : minsyms_read (false)
239 ~objfile_per_bfd_storage ();
241 /* The storage has an obstack of its own. */
243 auto_obstack storage_obstack
;
245 /* Byte cache for file names. */
247 gdb::bcache filename_cache
;
249 /* Byte cache for macros. */
251 gdb::bcache macro_cache
;
253 /* The gdbarch associated with the BFD. Note that this gdbarch is
254 determined solely from BFD information, without looking at target
255 information. The gdbarch determined from a running target may
256 differ from this e.g. with respect to register types and names. */
258 struct gdbarch
*gdbarch
= NULL
;
260 /* Hash table for mapping symbol names to demangled names. Each
261 entry in the hash table is a demangled_name_entry struct, storing the
262 language and two consecutive strings, both null-terminated; the first one
263 is a mangled or linkage name, and the second is the demangled name or just
264 a zero byte if the name doesn't demangle. */
266 htab_up demangled_names_hash
;
268 /* The per-objfile information about the entry point, the scope (file/func)
269 containing the entry point, and the scope of the user's main() func. */
273 /* The name and language of any "main" found in this objfile. The
274 name can be NULL, which means that the information was not
277 const char *name_of_main
= NULL
;
278 enum language language_of_main
= language_unknown
;
280 /* Each file contains a pointer to an array of minimal symbols for all
281 global symbols that are defined within the file. The array is
282 terminated by a "null symbol", one that has a NULL pointer for the
283 name and a zero value for the address. This makes it easy to walk
284 through the array when passed a pointer to somewhere in the middle
285 of it. There is also a count of the number of symbols, which does
286 not include the terminating null symbol. */
288 gdb::unique_xmalloc_ptr
<minimal_symbol
> msymbols
;
289 int minimal_symbol_count
= 0;
291 /* The number of minimal symbols read, before any minimal symbol
292 de-duplication is applied. Note in particular that this has only
293 a passing relationship with the actual size of the table above;
294 use minimal_symbol_count if you need the true size. */
298 /* This is true if minimal symbols have already been read. Symbol
299 readers can use this to bypass minimal symbol reading. Also, the
300 minimal symbol table management code in minsyms.c uses this to
301 suppress new minimal symbols. You might think that MSYMBOLS or
302 MINIMAL_SYMBOL_COUNT could be used for this, but it is possible
303 for multiple readers to install minimal symbols into a given
306 bool minsyms_read
: 1;
308 /* This is a hash table used to index the minimal symbols by (mangled)
311 minimal_symbol
*msymbol_hash
[MINIMAL_SYMBOL_HASH_SIZE
] {};
313 /* This hash table is used to index the minimal symbols by their
314 demangled names. Uses a language-specific hash function via
317 minimal_symbol
*msymbol_demangled_hash
[MINIMAL_SYMBOL_HASH_SIZE
] {};
319 /* All the different languages of symbols found in the demangled
321 std::bitset
<nr_languages
> demangled_hash_languages
;
324 /* An iterator that first returns a parent objfile, and then each
325 separate debug objfile. */
327 class separate_debug_iterator
331 explicit separate_debug_iterator (struct objfile
*objfile
)
332 : m_objfile (objfile
),
337 bool operator!= (const separate_debug_iterator
&other
)
339 return m_objfile
!= other
.m_objfile
;
342 separate_debug_iterator
&operator++ ();
344 struct objfile
*operator* ()
351 struct objfile
*m_objfile
;
352 struct objfile
*m_parent
;
355 /* A range adapter wrapping separate_debug_iterator. */
357 class separate_debug_range
361 explicit separate_debug_range (struct objfile
*objfile
)
362 : m_objfile (objfile
)
366 separate_debug_iterator
begin ()
368 return separate_debug_iterator (m_objfile
);
371 separate_debug_iterator
end ()
373 return separate_debug_iterator (nullptr);
378 struct objfile
*m_objfile
;
381 /* Master structure for keeping track of each file from which
382 gdb reads symbols. There are several ways these get allocated: 1.
383 The main symbol file, symfile_objfile, set by the symbol-file command,
384 2. Additional symbol files added by the add-symbol-file command,
385 3. Shared library objfiles, added by ADD_SOLIB, 4. symbol files
386 for modules that were loaded when GDB attached to a remote system
389 GDB typically reads symbols twice -- first an initial scan which just
390 reads "partial symbols"; these are partial information for the
391 static/global symbols in a symbol file. When later looking up symbols,
392 objfile->sf->qf->lookup_symbol is used to check if we only have a partial
393 symbol and if so, read and expand the full compunit. */
399 /* The only way to create an objfile is to call objfile::make. */
400 objfile (bfd
*, const char *, objfile_flags
);
404 /* Create an objfile. */
405 static objfile
*make (bfd
*bfd_
, const char *name_
, objfile_flags flags_
,
406 objfile
*parent
= nullptr);
410 DISABLE_COPY_AND_ASSIGN (objfile
);
412 /* A range adapter that makes it possible to iterate over all
413 psymtabs in one objfile. */
415 psymtab_storage::partial_symtab_range
psymtabs ()
417 return partial_symtabs
->range ();
420 /* Reset the storage for the partial symbol tables. */
422 void reset_psymtabs ()
424 psymbol_map
.clear ();
425 partial_symtabs
.reset (new psymtab_storage ());
428 typedef next_adapter
<struct compunit_symtab
> compunits_range
;
430 /* A range adapter that makes it possible to iterate over all
431 compunits in one objfile. */
433 compunits_range
compunits ()
435 return compunits_range (compunit_symtabs
);
438 /* A range adapter that makes it possible to iterate over all
439 minimal symbols of an objfile. */
445 explicit msymbols_range (struct objfile
*objfile
)
446 : m_objfile (objfile
)
450 minimal_symbol_iterator
begin () const
452 return minimal_symbol_iterator (m_objfile
->per_bfd
->msymbols
.get ());
455 minimal_symbol_iterator
end () const
457 return minimal_symbol_iterator
458 (m_objfile
->per_bfd
->msymbols
.get ()
459 + m_objfile
->per_bfd
->minimal_symbol_count
);
464 struct objfile
*m_objfile
;
467 /* Return a range adapter for iterating over all minimal
470 msymbols_range
msymbols ()
472 return msymbols_range (this);
475 /* Return a range adapter for iterating over all the separate debug
476 objfiles of this objfile. */
478 separate_debug_range
separate_debug_objfiles ()
480 return separate_debug_range (this);
484 /* All struct objfile's are chained together by their next pointers.
485 The program space field "objfiles" (frequently referenced via
486 the macro "object_files") points to the first link in this chain. */
488 struct objfile
*next
= nullptr;
490 /* The object file's original name as specified by the user,
491 made absolute, and tilde-expanded. However, it is not canonicalized
492 (i.e., it has not been passed through gdb_realpath).
493 This pointer is never NULL. This does not have to be freed; it is
494 guaranteed to have a lifetime at least as long as the objfile. */
496 const char *original_name
= nullptr;
498 CORE_ADDR addr_low
= 0;
500 /* Some flag bits for this objfile. */
504 /* The program space associated with this objfile. */
506 struct program_space
*pspace
;
508 /* List of compunits.
509 These are used to do symbol lookups and file/line-number lookups. */
511 struct compunit_symtab
*compunit_symtabs
= nullptr;
513 /* The partial symbol tables. */
515 std::shared_ptr
<psymtab_storage
> partial_symtabs
;
517 /* The object file's BFD. Can be null if the objfile contains only
518 minimal symbols, e.g. the run time common symbols for SunOS4. */
522 /* The per-BFD data. Note that this is treated specially if OBFD
525 struct objfile_per_bfd_storage
*per_bfd
= nullptr;
527 /* The modification timestamp of the object file, as of the last time
528 we read its symbols. */
532 /* Obstack to hold objects that should be freed when we load a new symbol
533 table from this object file. */
535 struct obstack objfile_obstack
{};
537 /* Map symbol addresses to the partial symtab that defines the
538 object at that address. */
540 std::vector
<std::pair
<CORE_ADDR
, partial_symtab
*>> psymbol_map
;
542 /* Structure which keeps track of functions that manipulate objfile's
543 of the same type as this objfile. I.e. the function to read partial
544 symbols for example. Note that this structure is in statically
545 allocated memory, and is shared by all objfiles that use the
546 object module reader of this type. */
548 const struct sym_fns
*sf
= nullptr;
550 /* Per objfile data-pointers required by other GDB modules. */
554 /* Set of relocation offsets to apply to each section.
555 The table is indexed by the_bfd_section->index, thus it is generally
556 as large as the number of sections in the binary.
557 The table is stored on the objfile_obstack.
559 These offsets indicate that all symbols (including partial and
560 minimal symbols) which have been read have been relocated by this
561 much. Symbols which are yet to be read need to be relocated by it. */
563 struct section_offsets
*section_offsets
= nullptr;
564 int num_sections
= 0;
566 /* Indexes in the section_offsets array. These are initialized by the
567 *_symfile_offsets() family of functions (som_symfile_offsets,
568 xcoff_symfile_offsets, default_symfile_offsets). In theory they
569 should correspond to the section indexes used by bfd for the
570 current objfile. The exception to this for the time being is the
573 These are initialized to -1 so that we can later detect if they
574 are used w/o being properly assigned to. */
576 int sect_index_text
= -1;
577 int sect_index_data
= -1;
578 int sect_index_bss
= -1;
579 int sect_index_rodata
= -1;
581 /* These pointers are used to locate the section table, which
582 among other things, is used to map pc addresses into sections.
583 SECTIONS points to the first entry in the table, and
584 SECTIONS_END points to the first location past the last entry
585 in the table. The table is stored on the objfile_obstack. The
586 sections are indexed by the BFD section index; but the
587 structure data is only valid for certain sections
588 (e.g. non-empty, SEC_ALLOC). */
590 struct obj_section
*sections
= nullptr;
591 struct obj_section
*sections_end
= nullptr;
593 /* GDB allows to have debug symbols in separate object files. This is
594 used by .gnu_debuglink, ELF build id note and Mach-O OSO.
595 Although this is a tree structure, GDB only support one level
596 (ie a separate debug for a separate debug is not supported). Note that
597 separate debug object are in the main chain and therefore will be
598 visited by objfiles & co iterators. Separate debug objfile always
599 has a non-nul separate_debug_objfile_backlink. */
601 /* Link to the first separate debug object, if any. */
603 struct objfile
*separate_debug_objfile
= nullptr;
605 /* If this is a separate debug object, this is used as a link to the
606 actual executable objfile. */
608 struct objfile
*separate_debug_objfile_backlink
= nullptr;
610 /* If this is a separate debug object, this is a link to the next one
611 for the same executable objfile. */
613 struct objfile
*separate_debug_objfile_link
= nullptr;
615 /* Place to stash various statistics about this objfile. */
619 /* A linked list of symbols created when reading template types or
620 function templates. These symbols are not stored in any symbol
621 table, so we have to keep them here to relocate them
624 struct symbol
*template_symbols
= nullptr;
626 /* Associate a static link (struct dynamic_prop *) to all blocks (struct
627 block *) that have one.
629 In the context of nested functions (available in Pascal, Ada and GNU C,
630 for instance), a static link (as in DWARF's DW_AT_static_link attribute)
631 for a function is a way to get the frame corresponding to the enclosing
634 Very few blocks have a static link, so it's more memory efficient to
635 store these here rather than in struct block. Static links must be
636 allocated on the objfile's obstack. */
637 htab_up static_links
;
640 /* Declarations for functions defined in objfiles.c */
642 extern struct gdbarch
*get_objfile_arch (const struct objfile
*);
644 extern int entry_point_address_query (CORE_ADDR
*entry_p
);
646 extern CORE_ADDR
entry_point_address (void);
648 extern void build_objfile_section_table (struct objfile
*);
650 extern void free_objfile_separate_debug (struct objfile
*);
652 extern void free_all_objfiles (void);
654 extern void objfile_relocate (struct objfile
*, const struct section_offsets
*);
655 extern void objfile_rebase (struct objfile
*, CORE_ADDR
);
657 extern int objfile_has_partial_symbols (struct objfile
*objfile
);
659 extern int objfile_has_full_symbols (struct objfile
*objfile
);
661 extern int objfile_has_symbols (struct objfile
*objfile
);
663 extern int have_partial_symbols (void);
665 extern int have_full_symbols (void);
667 extern void objfile_set_sym_fns (struct objfile
*objfile
,
668 const struct sym_fns
*sf
);
670 extern void objfiles_changed (void);
672 extern int is_addr_in_objfile (CORE_ADDR addr
, const struct objfile
*objfile
);
674 /* Return true if ADDRESS maps into one of the sections of a
675 OBJF_SHARED objfile of PSPACE and false otherwise. */
677 extern int shared_objfile_contains_address_p (struct program_space
*pspace
,
680 /* This operation deletes all objfile entries that represent solibs that
681 weren't explicitly loaded by the user, via e.g., the add-symbol-file
684 extern void objfile_purge_solibs (void);
686 /* Functions for dealing with the minimal symbol table, really a misc
687 address<->symbol mapping for things we don't have debug symbols for. */
689 extern int have_minimal_symbols (void);
691 extern struct obj_section
*find_pc_section (CORE_ADDR pc
);
693 /* Return non-zero if PC is in a section called NAME. */
694 extern int pc_in_section (CORE_ADDR
, const char *);
696 /* Return non-zero if PC is in a SVR4-style procedure linkage table
700 in_plt_section (CORE_ADDR pc
)
702 return pc_in_section (pc
, ".plt");
705 /* Keep a registry of per-objfile data-pointers required by other GDB
707 DECLARE_REGISTRY(objfile
);
709 /* In normal use, the section map will be rebuilt by find_pc_section
710 if objfiles have been added, removed or relocated since it was last
711 called. Calling inhibit_section_map_updates will inhibit this
712 behavior until the returned scoped_restore object is destroyed. If
713 you call inhibit_section_map_updates you must ensure that every
714 call to find_pc_section in the inhibited region relates to a
715 section that is already in the section map and has not since been
716 removed or relocated. */
717 extern scoped_restore_tmpl
<int> inhibit_section_map_updates
718 (struct program_space
*pspace
);
720 extern void default_iterate_over_objfiles_in_search_order
721 (struct gdbarch
*gdbarch
,
722 iterate_over_objfiles_in_search_order_cb_ftype
*cb
,
723 void *cb_data
, struct objfile
*current_objfile
);
726 #define ALL_OBJFILE_OSECTIONS(objfile, osect) \
727 for (osect = objfile->sections; osect < objfile->sections_end; osect++) \
728 if (osect->the_bfd_section == NULL) \
734 #define SECT_OFF_DATA(objfile) \
735 ((objfile->sect_index_data == -1) \
736 ? (internal_error (__FILE__, __LINE__, \
737 _("sect_index_data not initialized")), -1) \
738 : objfile->sect_index_data)
740 #define SECT_OFF_RODATA(objfile) \
741 ((objfile->sect_index_rodata == -1) \
742 ? (internal_error (__FILE__, __LINE__, \
743 _("sect_index_rodata not initialized")), -1) \
744 : objfile->sect_index_rodata)
746 #define SECT_OFF_TEXT(objfile) \
747 ((objfile->sect_index_text == -1) \
748 ? (internal_error (__FILE__, __LINE__, \
749 _("sect_index_text not initialized")), -1) \
750 : objfile->sect_index_text)
752 /* Sometimes the .bss section is missing from the objfile, so we don't
753 want to die here. Let the users of SECT_OFF_BSS deal with an
754 uninitialized section index. */
755 #define SECT_OFF_BSS(objfile) (objfile)->sect_index_bss
757 /* Answer whether there is more than one object file loaded. */
759 #define MULTI_OBJFILE_P() (object_files && object_files->next)
761 /* Reset the per-BFD storage area on OBJ. */
763 void set_objfile_per_bfd (struct objfile
*obj
);
765 /* Return canonical name for OBJFILE.
766 This is the real file name if the file has been opened.
767 Otherwise it is the original name supplied by the user. */
769 const char *objfile_name (const struct objfile
*objfile
);
771 /* Return the (real) file name of OBJFILE if the file has been opened,
772 otherwise return NULL. */
774 const char *objfile_filename (const struct objfile
*objfile
);
776 /* Return the name to print for OBJFILE in debugging messages. */
778 extern const char *objfile_debug_name (const struct objfile
*objfile
);
780 /* Return the name of the file format of OBJFILE if the file has been opened,
781 otherwise return NULL. */
783 const char *objfile_flavour_name (struct objfile
*objfile
);
785 /* Set the objfile's notion of the "main" name and language. */
787 extern void set_objfile_main_name (struct objfile
*objfile
,
788 const char *name
, enum language lang
);
790 extern void objfile_register_static_link
791 (struct objfile
*objfile
,
792 const struct block
*block
,
793 const struct dynamic_prop
*static_link
);
795 extern const struct dynamic_prop
*objfile_lookup_static_link
796 (struct objfile
*objfile
, const struct block
*block
);
798 #endif /* !defined (OBJFILES_H) */