1 /* Definitions for symbol file management in GDB.
3 Copyright (C) 1992-2020 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 #include "gdbsupport/next-iterator.h"
35 #include "gdbsupport/safe-iterator.h"
38 #include "gdbsupport/refcounted-object.h"
42 struct partial_symbol
;
44 /* This structure maintains information on a per-objfile basis about the
45 "entry point" of the objfile, and the scope within which the entry point
46 exists. It is possible that gdb will see more than one objfile that is
47 executable, each with its own entry point.
49 For example, for dynamically linked executables in SVR4, the dynamic linker
50 code is contained within the shared C library, which is actually executable
51 and is run by the kernel first when an exec is done of a user executable
52 that is dynamically linked. The dynamic linker within the shared C library
53 then maps in the various program segments in the user executable and jumps
54 to the user executable's recorded entry point, as if the call had been made
55 directly by the kernel.
57 The traditional gdb method of using this info was to use the
58 recorded entry point to set the entry-file's lowpc and highpc from
59 the debugging information, where these values are the starting
60 address (inclusive) and ending address (exclusive) of the
61 instruction space in the executable which correspond to the
62 "startup file", i.e. crt0.o in most cases. This file is assumed to
63 be a startup file and frames with pc's inside it are treated as
64 nonexistent. Setting these variables is necessary so that
65 backtraces do not fly off the bottom of the stack.
67 NOTE: cagney/2003-09-09: It turns out that this "traditional"
68 method doesn't work. Corinna writes: ``It turns out that the call
69 to test for "inside entry file" destroys a meaningful backtrace
70 under some conditions. E.g. the backtrace tests in the asm-source
71 testcase are broken for some targets. In this test the functions
72 are all implemented as part of one file and the testcase is not
73 necessarily linked with a start file (depending on the target).
74 What happens is, that the first frame is printed normally and
75 following frames are treated as being inside the entry file then.
76 This way, only the #0 frame is printed in the backtrace output.''
77 Ref "frame.c" "NOTE: vinschen/2003-04-01".
79 Gdb also supports an alternate method to avoid running off the bottom
82 There are two frames that are "special", the frame for the function
83 containing the process entry point, since it has no predecessor frame,
84 and the frame for the function containing the user code entry point
85 (the main() function), since all the predecessor frames are for the
86 process startup code. Since we have no guarantee that the linked
87 in startup modules have any debugging information that gdb can use,
88 we need to avoid following frame pointers back into frames that might
89 have been built in the startup code, as we might get hopelessly
90 confused. However, we almost always have debugging information
93 These variables are used to save the range of PC values which are
94 valid within the main() function and within the function containing
95 the process entry point. If we always consider the frame for
96 main() as the outermost frame when debugging user code, and the
97 frame for the process entry point function as the outermost frame
98 when debugging startup code, then all we have to do is have
99 DEPRECATED_FRAME_CHAIN_VALID return false whenever a frame's
100 current PC is within the range specified by these variables. In
101 essence, we set "ceilings" in the frame chain beyond which we will
102 not proceed when following the frame chain back up the stack.
104 A nice side effect is that we can still debug startup code without
105 running off the end of the frame chain, assuming that we have usable
106 debugging information in the startup modules, and if we choose to not
107 use the block at main, or can't find it for some reason, everything
108 still works as before. And if we have no startup code debugging
109 information but we do have usable information for main(), backtraces
110 from user code don't go wandering off into the startup code. */
114 /* The unrelocated value we should use for this objfile entry point. */
115 CORE_ADDR entry_point
;
117 /* The index of the section in which the entry point appears. */
118 int the_bfd_section_index
;
120 /* Set to 1 iff ENTRY_POINT contains a valid value. */
121 unsigned entry_point_p
: 1;
123 /* Set to 1 iff this object was initialized. */
124 unsigned initialized
: 1;
127 /* Sections in an objfile. The section offsets are stored in the
132 /* BFD section pointer */
133 struct bfd_section
*the_bfd_section
;
135 /* Objfile this section is part of. */
136 struct objfile
*objfile
;
138 /* True if this "overlay section" is mapped into an "overlay region". */
142 /* Relocation offset applied to S. */
143 #define obj_section_offset(s) \
144 (((s)->objfile->section_offsets)->offsets[gdb_bfd_section_index ((s)->objfile->obfd, (s)->the_bfd_section)])
146 /* The memory address of section S (vma + offset). */
147 #define obj_section_addr(s) \
148 (bfd_section_vma (s->the_bfd_section) \
149 + obj_section_offset (s))
151 /* The one-passed-the-end memory address of section S
152 (vma + size + offset). */
153 #define obj_section_endaddr(s) \
154 (bfd_section_vma (s->the_bfd_section) \
155 + bfd_section_size ((s)->the_bfd_section) \
156 + obj_section_offset (s))
158 /* The "objstats" structure provides a place for gdb to record some
159 interesting information about its internal state at runtime, on a
160 per objfile basis, such as information about the number of symbols
161 read, size of string table (if any), etc. */
165 /* Number of partial symbols read. */
168 /* Number of full symbols read. */
171 /* Number of ".stabs" read (if applicable). */
174 /* Number of types. */
177 /* Size of stringtable, (if applicable). */
181 #define OBJSTAT(objfile, expr) (objfile -> stats.expr)
182 #define OBJSTATS struct objstats stats
183 extern void print_objfile_statistics (void);
184 extern void print_symbol_bcache_statistics (void);
186 /* Number of entries in the minimal symbol hash table. */
187 #define MINIMAL_SYMBOL_HASH_SIZE 2039
189 /* An iterator for minimal symbols. */
191 struct minimal_symbol_iterator
193 typedef minimal_symbol_iterator self_type
;
194 typedef struct minimal_symbol
*value_type
;
195 typedef struct minimal_symbol
*&reference
;
196 typedef struct minimal_symbol
**pointer
;
197 typedef std::forward_iterator_tag iterator_category
;
198 typedef int difference_type
;
200 explicit minimal_symbol_iterator (struct minimal_symbol
*msym
)
205 value_type
operator* () const
210 bool operator== (const self_type
&other
) const
212 return m_msym
== other
.m_msym
;
215 bool operator!= (const self_type
&other
) const
217 return m_msym
!= other
.m_msym
;
220 self_type
&operator++ ()
227 struct minimal_symbol
*m_msym
;
230 /* Some objfile data is hung off the BFD. This enables sharing of the
231 data across all objfiles using the BFD. The data is stored in an
232 instance of this structure, and associated with the BFD using the
235 struct objfile_per_bfd_storage
237 objfile_per_bfd_storage ()
238 : minsyms_read (false)
241 ~objfile_per_bfd_storage ();
243 /* The storage has an obstack of its own. */
245 auto_obstack storage_obstack
;
247 /* Byte cache for file names. */
249 gdb::bcache filename_cache
;
251 /* Byte cache for macros. */
253 gdb::bcache macro_cache
;
255 /* The gdbarch associated with the BFD. Note that this gdbarch is
256 determined solely from BFD information, without looking at target
257 information. The gdbarch determined from a running target may
258 differ from this e.g. with respect to register types and names. */
260 struct gdbarch
*gdbarch
= NULL
;
262 /* Hash table for mapping symbol names to demangled names. Each
263 entry in the hash table is a demangled_name_entry struct, storing the
264 language and two consecutive strings, both null-terminated; the first one
265 is a mangled or linkage name, and the second is the demangled name or just
266 a zero byte if the name doesn't demangle. */
268 htab_up demangled_names_hash
;
270 /* The per-objfile information about the entry point, the scope (file/func)
271 containing the entry point, and the scope of the user's main() func. */
275 /* The name and language of any "main" found in this objfile. The
276 name can be NULL, which means that the information was not
279 const char *name_of_main
= NULL
;
280 enum language language_of_main
= language_unknown
;
282 /* Each file contains a pointer to an array of minimal symbols for all
283 global symbols that are defined within the file. The array is
284 terminated by a "null symbol", one that has a NULL pointer for the
285 name and a zero value for the address. This makes it easy to walk
286 through the array when passed a pointer to somewhere in the middle
287 of it. There is also a count of the number of symbols, which does
288 not include the terminating null symbol. */
290 gdb::unique_xmalloc_ptr
<minimal_symbol
> msymbols
;
291 int minimal_symbol_count
= 0;
293 /* The number of minimal symbols read, before any minimal symbol
294 de-duplication is applied. Note in particular that this has only
295 a passing relationship with the actual size of the table above;
296 use minimal_symbol_count if you need the true size. */
300 /* This is true if minimal symbols have already been read. Symbol
301 readers can use this to bypass minimal symbol reading. Also, the
302 minimal symbol table management code in minsyms.c uses this to
303 suppress new minimal symbols. You might think that MSYMBOLS or
304 MINIMAL_SYMBOL_COUNT could be used for this, but it is possible
305 for multiple readers to install minimal symbols into a given
308 bool minsyms_read
: 1;
310 /* This is a hash table used to index the minimal symbols by (mangled)
313 minimal_symbol
*msymbol_hash
[MINIMAL_SYMBOL_HASH_SIZE
] {};
315 /* This hash table is used to index the minimal symbols by their
316 demangled names. Uses a language-specific hash function via
319 minimal_symbol
*msymbol_demangled_hash
[MINIMAL_SYMBOL_HASH_SIZE
] {};
321 /* All the different languages of symbols found in the demangled
323 std::bitset
<nr_languages
> demangled_hash_languages
;
326 /* An iterator that first returns a parent objfile, and then each
327 separate debug objfile. */
329 class separate_debug_iterator
333 explicit separate_debug_iterator (struct objfile
*objfile
)
334 : m_objfile (objfile
),
339 bool operator!= (const separate_debug_iterator
&other
)
341 return m_objfile
!= other
.m_objfile
;
344 separate_debug_iterator
&operator++ ();
346 struct objfile
*operator* ()
353 struct objfile
*m_objfile
;
354 struct objfile
*m_parent
;
357 /* A range adapter wrapping separate_debug_iterator. */
359 class separate_debug_range
363 explicit separate_debug_range (struct objfile
*objfile
)
364 : m_objfile (objfile
)
368 separate_debug_iterator
begin ()
370 return separate_debug_iterator (m_objfile
);
373 separate_debug_iterator
end ()
375 return separate_debug_iterator (nullptr);
380 struct objfile
*m_objfile
;
383 /* Master structure for keeping track of each file from which
384 gdb reads symbols. There are several ways these get allocated: 1.
385 The main symbol file, symfile_objfile, set by the symbol-file command,
386 2. Additional symbol files added by the add-symbol-file command,
387 3. Shared library objfiles, added by ADD_SOLIB, 4. symbol files
388 for modules that were loaded when GDB attached to a remote system
391 GDB typically reads symbols twice -- first an initial scan which just
392 reads "partial symbols"; these are partial information for the
393 static/global symbols in a symbol file. When later looking up symbols,
394 objfile->sf->qf->lookup_symbol is used to check if we only have a partial
395 symbol and if so, read and expand the full compunit. */
401 /* The only way to create an objfile is to call objfile::make. */
402 objfile (bfd
*, const char *, objfile_flags
);
406 /* Normally you should not call delete. Instead, call 'unlink' to
407 remove it from the program space's list. In some cases, you may
408 need to hold a reference to an objfile that is independent of its
409 existence on the program space's list; for this case, the
410 destructor must be public so that shared_ptr can reference
414 /* Create an objfile. */
415 static objfile
*make (bfd
*bfd_
, const char *name_
, objfile_flags flags_
,
416 objfile
*parent
= nullptr);
418 /* Remove an objfile from the current program space, and free
422 DISABLE_COPY_AND_ASSIGN (objfile
);
424 /* A range adapter that makes it possible to iterate over all
425 psymtabs in one objfile. */
427 psymtab_storage::partial_symtab_range
psymtabs ()
429 return partial_symtabs
->range ();
432 /* Reset the storage for the partial symbol tables. */
434 void reset_psymtabs ()
436 psymbol_map
.clear ();
437 partial_symtabs
.reset (new psymtab_storage ());
440 typedef next_adapter
<struct compunit_symtab
> compunits_range
;
442 /* A range adapter that makes it possible to iterate over all
443 compunits in one objfile. */
445 compunits_range
compunits ()
447 return compunits_range (compunit_symtabs
);
450 /* A range adapter that makes it possible to iterate over all
451 minimal symbols of an objfile. */
457 explicit msymbols_range (struct objfile
*objfile
)
458 : m_objfile (objfile
)
462 minimal_symbol_iterator
begin () const
464 return minimal_symbol_iterator (m_objfile
->per_bfd
->msymbols
.get ());
467 minimal_symbol_iterator
end () const
469 return minimal_symbol_iterator
470 (m_objfile
->per_bfd
->msymbols
.get ()
471 + m_objfile
->per_bfd
->minimal_symbol_count
);
476 struct objfile
*m_objfile
;
479 /* Return a range adapter for iterating over all minimal
482 msymbols_range
msymbols ()
484 return msymbols_range (this);
487 /* Return a range adapter for iterating over all the separate debug
488 objfiles of this objfile. */
490 separate_debug_range
separate_debug_objfiles ()
492 return separate_debug_range (this);
496 /* The object file's original name as specified by the user,
497 made absolute, and tilde-expanded. However, it is not canonicalized
498 (i.e., it has not been passed through gdb_realpath).
499 This pointer is never NULL. This does not have to be freed; it is
500 guaranteed to have a lifetime at least as long as the objfile. */
502 const char *original_name
= nullptr;
504 CORE_ADDR addr_low
= 0;
506 /* Some flag bits for this objfile. */
510 /* The program space associated with this objfile. */
512 struct program_space
*pspace
;
514 /* List of compunits.
515 These are used to do symbol lookups and file/line-number lookups. */
517 struct compunit_symtab
*compunit_symtabs
= nullptr;
519 /* The partial symbol tables. */
521 std::unique_ptr
<psymtab_storage
> partial_symtabs
;
523 /* The object file's BFD. Can be null if the objfile contains only
524 minimal symbols, e.g. the run time common symbols for SunOS4. */
528 /* The per-BFD data. Note that this is treated specially if OBFD
531 struct objfile_per_bfd_storage
*per_bfd
= nullptr;
533 /* The modification timestamp of the object file, as of the last time
534 we read its symbols. */
538 /* Obstack to hold objects that should be freed when we load a new symbol
539 table from this object file. */
541 struct obstack objfile_obstack
{};
543 /* Map symbol addresses to the partial symtab that defines the
544 object at that address. */
546 std::vector
<std::pair
<CORE_ADDR
, partial_symtab
*>> psymbol_map
;
548 /* Structure which keeps track of functions that manipulate objfile's
549 of the same type as this objfile. I.e. the function to read partial
550 symbols for example. Note that this structure is in statically
551 allocated memory, and is shared by all objfiles that use the
552 object module reader of this type. */
554 const struct sym_fns
*sf
= nullptr;
556 /* Per objfile data-pointers required by other GDB modules. */
560 /* Set of relocation offsets to apply to each section.
561 The table is indexed by the_bfd_section->index, thus it is generally
562 as large as the number of sections in the binary.
563 The table is stored on the objfile_obstack.
565 These offsets indicate that all symbols (including partial and
566 minimal symbols) which have been read have been relocated by this
567 much. Symbols which are yet to be read need to be relocated by it. */
569 struct section_offsets
*section_offsets
= nullptr;
570 int num_sections
= 0;
572 /* Indexes in the section_offsets array. These are initialized by the
573 *_symfile_offsets() family of functions (som_symfile_offsets,
574 xcoff_symfile_offsets, default_symfile_offsets). In theory they
575 should correspond to the section indexes used by bfd for the
576 current objfile. The exception to this for the time being is the
579 These are initialized to -1 so that we can later detect if they
580 are used w/o being properly assigned to. */
582 int sect_index_text
= -1;
583 int sect_index_data
= -1;
584 int sect_index_bss
= -1;
585 int sect_index_rodata
= -1;
587 /* These pointers are used to locate the section table, which
588 among other things, is used to map pc addresses into sections.
589 SECTIONS points to the first entry in the table, and
590 SECTIONS_END points to the first location past the last entry
591 in the table. The table is stored on the objfile_obstack. The
592 sections are indexed by the BFD section index; but the
593 structure data is only valid for certain sections
594 (e.g. non-empty, SEC_ALLOC). */
596 struct obj_section
*sections
= nullptr;
597 struct obj_section
*sections_end
= nullptr;
599 /* GDB allows to have debug symbols in separate object files. This is
600 used by .gnu_debuglink, ELF build id note and Mach-O OSO.
601 Although this is a tree structure, GDB only support one level
602 (ie a separate debug for a separate debug is not supported). Note that
603 separate debug object are in the main chain and therefore will be
604 visited by objfiles & co iterators. Separate debug objfile always
605 has a non-nul separate_debug_objfile_backlink. */
607 /* Link to the first separate debug object, if any. */
609 struct objfile
*separate_debug_objfile
= nullptr;
611 /* If this is a separate debug object, this is used as a link to the
612 actual executable objfile. */
614 struct objfile
*separate_debug_objfile_backlink
= nullptr;
616 /* If this is a separate debug object, this is a link to the next one
617 for the same executable objfile. */
619 struct objfile
*separate_debug_objfile_link
= nullptr;
621 /* Place to stash various statistics about this objfile. */
625 /* A linked list of symbols created when reading template types or
626 function templates. These symbols are not stored in any symbol
627 table, so we have to keep them here to relocate them
630 struct symbol
*template_symbols
= nullptr;
632 /* Associate a static link (struct dynamic_prop *) to all blocks (struct
633 block *) that have one.
635 In the context of nested functions (available in Pascal, Ada and GNU C,
636 for instance), a static link (as in DWARF's DW_AT_static_link attribute)
637 for a function is a way to get the frame corresponding to the enclosing
640 Very few blocks have a static link, so it's more memory efficient to
641 store these here rather than in struct block. Static links must be
642 allocated on the objfile's obstack. */
643 htab_up static_links
;
646 /* A deleter for objfile. */
648 struct objfile_deleter
650 void operator() (objfile
*ptr
) const
656 /* A unique pointer that holds an objfile. */
658 typedef std::unique_ptr
<objfile
, objfile_deleter
> objfile_up
;
660 /* Declarations for functions defined in objfiles.c */
662 extern struct gdbarch
*get_objfile_arch (const struct objfile
*);
664 extern int entry_point_address_query (CORE_ADDR
*entry_p
);
666 extern CORE_ADDR
entry_point_address (void);
668 extern void build_objfile_section_table (struct objfile
*);
670 extern void free_objfile_separate_debug (struct objfile
*);
672 extern void objfile_relocate (struct objfile
*, const struct section_offsets
*);
673 extern void objfile_rebase (struct objfile
*, CORE_ADDR
);
675 extern int objfile_has_partial_symbols (struct objfile
*objfile
);
677 extern int objfile_has_full_symbols (struct objfile
*objfile
);
679 extern int objfile_has_symbols (struct objfile
*objfile
);
681 extern int have_partial_symbols (void);
683 extern int have_full_symbols (void);
685 extern void objfile_set_sym_fns (struct objfile
*objfile
,
686 const struct sym_fns
*sf
);
688 extern void objfiles_changed (void);
690 extern int is_addr_in_objfile (CORE_ADDR addr
, const struct objfile
*objfile
);
692 /* Return true if ADDRESS maps into one of the sections of a
693 OBJF_SHARED objfile of PSPACE and false otherwise. */
695 extern int shared_objfile_contains_address_p (struct program_space
*pspace
,
698 /* This operation deletes all objfile entries that represent solibs that
699 weren't explicitly loaded by the user, via e.g., the add-symbol-file
702 extern void objfile_purge_solibs (void);
704 /* Functions for dealing with the minimal symbol table, really a misc
705 address<->symbol mapping for things we don't have debug symbols for. */
707 extern int have_minimal_symbols (void);
709 extern struct obj_section
*find_pc_section (CORE_ADDR pc
);
711 /* Return non-zero if PC is in a section called NAME. */
712 extern int pc_in_section (CORE_ADDR
, const char *);
714 /* Return non-zero if PC is in a SVR4-style procedure linkage table
718 in_plt_section (CORE_ADDR pc
)
720 return pc_in_section (pc
, ".plt");
723 /* Keep a registry of per-objfile data-pointers required by other GDB
725 DECLARE_REGISTRY(objfile
);
727 /* In normal use, the section map will be rebuilt by find_pc_section
728 if objfiles have been added, removed or relocated since it was last
729 called. Calling inhibit_section_map_updates will inhibit this
730 behavior until the returned scoped_restore object is destroyed. If
731 you call inhibit_section_map_updates you must ensure that every
732 call to find_pc_section in the inhibited region relates to a
733 section that is already in the section map and has not since been
734 removed or relocated. */
735 extern scoped_restore_tmpl
<int> inhibit_section_map_updates
736 (struct program_space
*pspace
);
738 extern void default_iterate_over_objfiles_in_search_order
739 (struct gdbarch
*gdbarch
,
740 iterate_over_objfiles_in_search_order_cb_ftype
*cb
,
741 void *cb_data
, struct objfile
*current_objfile
);
744 #define ALL_OBJFILE_OSECTIONS(objfile, osect) \
745 for (osect = objfile->sections; osect < objfile->sections_end; osect++) \
746 if (osect->the_bfd_section == NULL) \
752 #define SECT_OFF_DATA(objfile) \
753 ((objfile->sect_index_data == -1) \
754 ? (internal_error (__FILE__, __LINE__, \
755 _("sect_index_data not initialized")), -1) \
756 : objfile->sect_index_data)
758 #define SECT_OFF_RODATA(objfile) \
759 ((objfile->sect_index_rodata == -1) \
760 ? (internal_error (__FILE__, __LINE__, \
761 _("sect_index_rodata not initialized")), -1) \
762 : objfile->sect_index_rodata)
764 #define SECT_OFF_TEXT(objfile) \
765 ((objfile->sect_index_text == -1) \
766 ? (internal_error (__FILE__, __LINE__, \
767 _("sect_index_text not initialized")), -1) \
768 : objfile->sect_index_text)
770 /* Sometimes the .bss section is missing from the objfile, so we don't
771 want to die here. Let the users of SECT_OFF_BSS deal with an
772 uninitialized section index. */
773 #define SECT_OFF_BSS(objfile) (objfile)->sect_index_bss
775 /* Reset the per-BFD storage area on OBJ. */
777 void set_objfile_per_bfd (struct objfile
*obj
);
779 /* Return canonical name for OBJFILE.
780 This is the real file name if the file has been opened.
781 Otherwise it is the original name supplied by the user. */
783 const char *objfile_name (const struct objfile
*objfile
);
785 /* Return the (real) file name of OBJFILE if the file has been opened,
786 otherwise return NULL. */
788 const char *objfile_filename (const struct objfile
*objfile
);
790 /* Return the name to print for OBJFILE in debugging messages. */
792 extern const char *objfile_debug_name (const struct objfile
*objfile
);
794 /* Return the name of the file format of OBJFILE if the file has been opened,
795 otherwise return NULL. */
797 const char *objfile_flavour_name (struct objfile
*objfile
);
799 /* Set the objfile's notion of the "main" name and language. */
801 extern void set_objfile_main_name (struct objfile
*objfile
,
802 const char *name
, enum language lang
);
804 extern void objfile_register_static_link
805 (struct objfile
*objfile
,
806 const struct block
*block
,
807 const struct dynamic_prop
*static_link
);
809 extern const struct dynamic_prop
*objfile_lookup_static_link
810 (struct objfile
*objfile
, const struct block
*block
);
812 #endif /* !defined (OBJFILES_H) */