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)[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 #define ALL_OBJFILE_OSECTIONS(objfile, osect) \
159 for (osect = objfile->sections; osect < objfile->sections_end; osect++) \
160 if (osect->the_bfd_section == NULL) \
166 #define SECT_OFF_DATA(objfile) \
167 ((objfile->sect_index_data == -1) \
168 ? (internal_error (__FILE__, __LINE__, \
169 _("sect_index_data not initialized")), -1) \
170 : objfile->sect_index_data)
172 #define SECT_OFF_RODATA(objfile) \
173 ((objfile->sect_index_rodata == -1) \
174 ? (internal_error (__FILE__, __LINE__, \
175 _("sect_index_rodata not initialized")), -1) \
176 : objfile->sect_index_rodata)
178 #define SECT_OFF_TEXT(objfile) \
179 ((objfile->sect_index_text == -1) \
180 ? (internal_error (__FILE__, __LINE__, \
181 _("sect_index_text not initialized")), -1) \
182 : objfile->sect_index_text)
184 /* Sometimes the .bss section is missing from the objfile, so we don't
185 want to die here. Let the users of SECT_OFF_BSS deal with an
186 uninitialized section index. */
187 #define SECT_OFF_BSS(objfile) (objfile)->sect_index_bss
189 /* The "objstats" structure provides a place for gdb to record some
190 interesting information about its internal state at runtime, on a
191 per objfile basis, such as information about the number of symbols
192 read, size of string table (if any), etc. */
196 /* Number of partial symbols read. */
199 /* Number of full symbols read. */
202 /* Number of ".stabs" read (if applicable). */
205 /* Number of types. */
208 /* Size of stringtable, (if applicable). */
212 #define OBJSTAT(objfile, expr) (objfile -> stats.expr)
213 #define OBJSTATS struct objstats stats
214 extern void print_objfile_statistics (void);
215 extern void print_symbol_bcache_statistics (void);
217 /* Number of entries in the minimal symbol hash table. */
218 #define MINIMAL_SYMBOL_HASH_SIZE 2039
220 /* An iterator for minimal symbols. */
222 struct minimal_symbol_iterator
224 typedef minimal_symbol_iterator self_type
;
225 typedef struct minimal_symbol
*value_type
;
226 typedef struct minimal_symbol
*&reference
;
227 typedef struct minimal_symbol
**pointer
;
228 typedef std::forward_iterator_tag iterator_category
;
229 typedef int difference_type
;
231 explicit minimal_symbol_iterator (struct minimal_symbol
*msym
)
236 value_type
operator* () const
241 bool operator== (const self_type
&other
) const
243 return m_msym
== other
.m_msym
;
246 bool operator!= (const self_type
&other
) const
248 return m_msym
!= other
.m_msym
;
251 self_type
&operator++ ()
258 struct minimal_symbol
*m_msym
;
261 /* Some objfile data is hung off the BFD. This enables sharing of the
262 data across all objfiles using the BFD. The data is stored in an
263 instance of this structure, and associated with the BFD using the
266 struct objfile_per_bfd_storage
268 objfile_per_bfd_storage ()
269 : minsyms_read (false)
272 ~objfile_per_bfd_storage ();
274 /* The storage has an obstack of its own. */
276 auto_obstack storage_obstack
;
278 /* Byte cache for file names. */
280 gdb::bcache filename_cache
;
282 /* Byte cache for macros. */
284 gdb::bcache macro_cache
;
286 /* The gdbarch associated with the BFD. Note that this gdbarch is
287 determined solely from BFD information, without looking at target
288 information. The gdbarch determined from a running target may
289 differ from this e.g. with respect to register types and names. */
291 struct gdbarch
*gdbarch
= NULL
;
293 /* Hash table for mapping symbol names to demangled names. Each
294 entry in the hash table is a demangled_name_entry struct, storing the
295 language and two consecutive strings, both null-terminated; the first one
296 is a mangled or linkage name, and the second is the demangled name or just
297 a zero byte if the name doesn't demangle. */
299 htab_up demangled_names_hash
;
301 /* The per-objfile information about the entry point, the scope (file/func)
302 containing the entry point, and the scope of the user's main() func. */
306 /* The name and language of any "main" found in this objfile. The
307 name can be NULL, which means that the information was not
310 const char *name_of_main
= NULL
;
311 enum language language_of_main
= language_unknown
;
313 /* Each file contains a pointer to an array of minimal symbols for all
314 global symbols that are defined within the file. The array is
315 terminated by a "null symbol", one that has a NULL pointer for the
316 name and a zero value for the address. This makes it easy to walk
317 through the array when passed a pointer to somewhere in the middle
318 of it. There is also a count of the number of symbols, which does
319 not include the terminating null symbol. */
321 gdb::unique_xmalloc_ptr
<minimal_symbol
> msymbols
;
322 int minimal_symbol_count
= 0;
324 /* The number of minimal symbols read, before any minimal symbol
325 de-duplication is applied. Note in particular that this has only
326 a passing relationship with the actual size of the table above;
327 use minimal_symbol_count if you need the true size. */
331 /* This is true if minimal symbols have already been read. Symbol
332 readers can use this to bypass minimal symbol reading. Also, the
333 minimal symbol table management code in minsyms.c uses this to
334 suppress new minimal symbols. You might think that MSYMBOLS or
335 MINIMAL_SYMBOL_COUNT could be used for this, but it is possible
336 for multiple readers to install minimal symbols into a given
339 bool minsyms_read
: 1;
341 /* This is a hash table used to index the minimal symbols by (mangled)
344 minimal_symbol
*msymbol_hash
[MINIMAL_SYMBOL_HASH_SIZE
] {};
346 /* This hash table is used to index the minimal symbols by their
347 demangled names. Uses a language-specific hash function via
350 minimal_symbol
*msymbol_demangled_hash
[MINIMAL_SYMBOL_HASH_SIZE
] {};
352 /* All the different languages of symbols found in the demangled
354 std::bitset
<nr_languages
> demangled_hash_languages
;
357 /* An iterator that first returns a parent objfile, and then each
358 separate debug objfile. */
360 class separate_debug_iterator
364 explicit separate_debug_iterator (struct objfile
*objfile
)
365 : m_objfile (objfile
),
370 bool operator!= (const separate_debug_iterator
&other
)
372 return m_objfile
!= other
.m_objfile
;
375 separate_debug_iterator
&operator++ ();
377 struct objfile
*operator* ()
384 struct objfile
*m_objfile
;
385 struct objfile
*m_parent
;
388 /* A range adapter wrapping separate_debug_iterator. */
390 class separate_debug_range
394 explicit separate_debug_range (struct objfile
*objfile
)
395 : m_objfile (objfile
)
399 separate_debug_iterator
begin ()
401 return separate_debug_iterator (m_objfile
);
404 separate_debug_iterator
end ()
406 return separate_debug_iterator (nullptr);
411 struct objfile
*m_objfile
;
414 /* Master structure for keeping track of each file from which
415 gdb reads symbols. There are several ways these get allocated: 1.
416 The main symbol file, symfile_objfile, set by the symbol-file command,
417 2. Additional symbol files added by the add-symbol-file command,
418 3. Shared library objfiles, added by ADD_SOLIB, 4. symbol files
419 for modules that were loaded when GDB attached to a remote system
422 GDB typically reads symbols twice -- first an initial scan which just
423 reads "partial symbols"; these are partial information for the
424 static/global symbols in a symbol file. When later looking up symbols,
425 objfile->sf->qf->lookup_symbol is used to check if we only have a partial
426 symbol and if so, read and expand the full compunit. */
432 /* The only way to create an objfile is to call objfile::make. */
433 objfile (bfd
*, const char *, objfile_flags
);
437 /* Normally you should not call delete. Instead, call 'unlink' to
438 remove it from the program space's list. In some cases, you may
439 need to hold a reference to an objfile that is independent of its
440 existence on the program space's list; for this case, the
441 destructor must be public so that shared_ptr can reference
445 /* Create an objfile. */
446 static objfile
*make (bfd
*bfd_
, const char *name_
, objfile_flags flags_
,
447 objfile
*parent
= nullptr);
449 /* Remove an objfile from the current program space, and free
453 DISABLE_COPY_AND_ASSIGN (objfile
);
455 /* A range adapter that makes it possible to iterate over all
456 psymtabs in one objfile. */
458 psymtab_storage::partial_symtab_range
psymtabs ()
460 return partial_symtabs
->range ();
463 /* Reset the storage for the partial symbol tables. */
465 void reset_psymtabs ()
467 psymbol_map
.clear ();
468 partial_symtabs
.reset (new psymtab_storage ());
471 typedef next_adapter
<struct compunit_symtab
> compunits_range
;
473 /* A range adapter that makes it possible to iterate over all
474 compunits in one objfile. */
476 compunits_range
compunits ()
478 return compunits_range (compunit_symtabs
);
481 /* A range adapter that makes it possible to iterate over all
482 minimal symbols of an objfile. */
488 explicit msymbols_range (struct objfile
*objfile
)
489 : m_objfile (objfile
)
493 minimal_symbol_iterator
begin () const
495 return minimal_symbol_iterator (m_objfile
->per_bfd
->msymbols
.get ());
498 minimal_symbol_iterator
end () const
500 return minimal_symbol_iterator
501 (m_objfile
->per_bfd
->msymbols
.get ()
502 + m_objfile
->per_bfd
->minimal_symbol_count
);
507 struct objfile
*m_objfile
;
510 /* Return a range adapter for iterating over all minimal
513 msymbols_range
msymbols ()
515 return msymbols_range (this);
518 /* Return a range adapter for iterating over all the separate debug
519 objfiles of this objfile. */
521 separate_debug_range
separate_debug_objfiles ()
523 return separate_debug_range (this);
526 CORE_ADDR
text_section_offset () const
528 return section_offsets
[SECT_OFF_TEXT (this)];
531 CORE_ADDR
data_section_offset () const
533 return section_offsets
[SECT_OFF_DATA (this)];
536 /* The object file's original name as specified by the user,
537 made absolute, and tilde-expanded. However, it is not canonicalized
538 (i.e., it has not been passed through gdb_realpath).
539 This pointer is never NULL. This does not have to be freed; it is
540 guaranteed to have a lifetime at least as long as the objfile. */
542 const char *original_name
= nullptr;
544 CORE_ADDR addr_low
= 0;
546 /* Some flag bits for this objfile. */
550 /* The program space associated with this objfile. */
552 struct program_space
*pspace
;
554 /* List of compunits.
555 These are used to do symbol lookups and file/line-number lookups. */
557 struct compunit_symtab
*compunit_symtabs
= nullptr;
559 /* The partial symbol tables. */
561 std::unique_ptr
<psymtab_storage
> partial_symtabs
;
563 /* The object file's BFD. Can be null if the objfile contains only
564 minimal symbols, e.g. the run time common symbols for SunOS4. */
568 /* The per-BFD data. Note that this is treated specially if OBFD
571 struct objfile_per_bfd_storage
*per_bfd
= nullptr;
573 /* The modification timestamp of the object file, as of the last time
574 we read its symbols. */
578 /* Obstack to hold objects that should be freed when we load a new symbol
579 table from this object file. */
581 struct obstack objfile_obstack
{};
583 /* Map symbol addresses to the partial symtab that defines the
584 object at that address. */
586 std::vector
<std::pair
<CORE_ADDR
, partial_symtab
*>> psymbol_map
;
588 /* Structure which keeps track of functions that manipulate objfile's
589 of the same type as this objfile. I.e. the function to read partial
590 symbols for example. Note that this structure is in statically
591 allocated memory, and is shared by all objfiles that use the
592 object module reader of this type. */
594 const struct sym_fns
*sf
= nullptr;
596 /* Per objfile data-pointers required by other GDB modules. */
600 /* Set of relocation offsets to apply to each section.
601 The table is indexed by the_bfd_section->index, thus it is generally
602 as large as the number of sections in the binary.
604 These offsets indicate that all symbols (including partial and
605 minimal symbols) which have been read have been relocated by this
606 much. Symbols which are yet to be read need to be relocated by it. */
608 ::section_offsets section_offsets
;
610 /* Indexes in the section_offsets array. These are initialized by the
611 *_symfile_offsets() family of functions (som_symfile_offsets,
612 xcoff_symfile_offsets, default_symfile_offsets). In theory they
613 should correspond to the section indexes used by bfd for the
614 current objfile. The exception to this for the time being is the
617 These are initialized to -1 so that we can later detect if they
618 are used w/o being properly assigned to. */
620 int sect_index_text
= -1;
621 int sect_index_data
= -1;
622 int sect_index_bss
= -1;
623 int sect_index_rodata
= -1;
625 /* These pointers are used to locate the section table, which
626 among other things, is used to map pc addresses into sections.
627 SECTIONS points to the first entry in the table, and
628 SECTIONS_END points to the first location past the last entry
629 in the table. The table is stored on the objfile_obstack. The
630 sections are indexed by the BFD section index; but the
631 structure data is only valid for certain sections
632 (e.g. non-empty, SEC_ALLOC). */
634 struct obj_section
*sections
= nullptr;
635 struct obj_section
*sections_end
= nullptr;
637 /* GDB allows to have debug symbols in separate object files. This is
638 used by .gnu_debuglink, ELF build id note and Mach-O OSO.
639 Although this is a tree structure, GDB only support one level
640 (ie a separate debug for a separate debug is not supported). Note that
641 separate debug object are in the main chain and therefore will be
642 visited by objfiles & co iterators. Separate debug objfile always
643 has a non-nul separate_debug_objfile_backlink. */
645 /* Link to the first separate debug object, if any. */
647 struct objfile
*separate_debug_objfile
= nullptr;
649 /* If this is a separate debug object, this is used as a link to the
650 actual executable objfile. */
652 struct objfile
*separate_debug_objfile_backlink
= nullptr;
654 /* If this is a separate debug object, this is a link to the next one
655 for the same executable objfile. */
657 struct objfile
*separate_debug_objfile_link
= nullptr;
659 /* Place to stash various statistics about this objfile. */
663 /* A linked list of symbols created when reading template types or
664 function templates. These symbols are not stored in any symbol
665 table, so we have to keep them here to relocate them
668 struct symbol
*template_symbols
= nullptr;
670 /* Associate a static link (struct dynamic_prop *) to all blocks (struct
671 block *) that have one.
673 In the context of nested functions (available in Pascal, Ada and GNU C,
674 for instance), a static link (as in DWARF's DW_AT_static_link attribute)
675 for a function is a way to get the frame corresponding to the enclosing
678 Very few blocks have a static link, so it's more memory efficient to
679 store these here rather than in struct block. Static links must be
680 allocated on the objfile's obstack. */
681 htab_up static_links
;
684 /* A deleter for objfile. */
686 struct objfile_deleter
688 void operator() (objfile
*ptr
) const
694 /* A unique pointer that holds an objfile. */
696 typedef std::unique_ptr
<objfile
, objfile_deleter
> objfile_up
;
698 /* Declarations for functions defined in objfiles.c */
700 extern struct gdbarch
*get_objfile_arch (const struct objfile
*);
702 extern int entry_point_address_query (CORE_ADDR
*entry_p
);
704 extern CORE_ADDR
entry_point_address (void);
706 extern void build_objfile_section_table (struct objfile
*);
708 extern void free_objfile_separate_debug (struct objfile
*);
710 extern void objfile_relocate (struct objfile
*, const section_offsets
&);
711 extern void objfile_rebase (struct objfile
*, CORE_ADDR
);
713 extern int objfile_has_partial_symbols (struct objfile
*objfile
);
715 extern int objfile_has_full_symbols (struct objfile
*objfile
);
717 extern int objfile_has_symbols (struct objfile
*objfile
);
719 extern int have_partial_symbols (void);
721 extern int have_full_symbols (void);
723 extern void objfile_set_sym_fns (struct objfile
*objfile
,
724 const struct sym_fns
*sf
);
726 extern void objfiles_changed (void);
728 extern int is_addr_in_objfile (CORE_ADDR addr
, const struct objfile
*objfile
);
730 /* Return true if ADDRESS maps into one of the sections of a
731 OBJF_SHARED objfile of PSPACE and false otherwise. */
733 extern int shared_objfile_contains_address_p (struct program_space
*pspace
,
736 /* This operation deletes all objfile entries that represent solibs that
737 weren't explicitly loaded by the user, via e.g., the add-symbol-file
740 extern void objfile_purge_solibs (void);
742 /* Functions for dealing with the minimal symbol table, really a misc
743 address<->symbol mapping for things we don't have debug symbols for. */
745 extern int have_minimal_symbols (void);
747 extern struct obj_section
*find_pc_section (CORE_ADDR pc
);
749 /* Return non-zero if PC is in a section called NAME. */
750 extern int pc_in_section (CORE_ADDR
, const char *);
752 /* Return non-zero if PC is in a SVR4-style procedure linkage table
756 in_plt_section (CORE_ADDR pc
)
758 return pc_in_section (pc
, ".plt");
761 /* Keep a registry of per-objfile data-pointers required by other GDB
763 DECLARE_REGISTRY(objfile
);
765 /* In normal use, the section map will be rebuilt by find_pc_section
766 if objfiles have been added, removed or relocated since it was last
767 called. Calling inhibit_section_map_updates will inhibit this
768 behavior until the returned scoped_restore object is destroyed. If
769 you call inhibit_section_map_updates you must ensure that every
770 call to find_pc_section in the inhibited region relates to a
771 section that is already in the section map and has not since been
772 removed or relocated. */
773 extern scoped_restore_tmpl
<int> inhibit_section_map_updates
774 (struct program_space
*pspace
);
776 extern void default_iterate_over_objfiles_in_search_order
777 (struct gdbarch
*gdbarch
,
778 iterate_over_objfiles_in_search_order_cb_ftype
*cb
,
779 void *cb_data
, struct objfile
*current_objfile
);
781 /* Reset the per-BFD storage area on OBJ. */
783 void set_objfile_per_bfd (struct objfile
*obj
);
785 /* Return canonical name for OBJFILE.
786 This is the real file name if the file has been opened.
787 Otherwise it is the original name supplied by the user. */
789 const char *objfile_name (const struct objfile
*objfile
);
791 /* Return the (real) file name of OBJFILE if the file has been opened,
792 otherwise return NULL. */
794 const char *objfile_filename (const struct objfile
*objfile
);
796 /* Return the name to print for OBJFILE in debugging messages. */
798 extern const char *objfile_debug_name (const struct objfile
*objfile
);
800 /* Return the name of the file format of OBJFILE if the file has been opened,
801 otherwise return NULL. */
803 const char *objfile_flavour_name (struct objfile
*objfile
);
805 /* Set the objfile's notion of the "main" name and language. */
807 extern void set_objfile_main_name (struct objfile
*objfile
,
808 const char *name
, enum language lang
);
810 extern void objfile_register_static_link
811 (struct objfile
*objfile
,
812 const struct block
*block
,
813 const struct dynamic_prop
*static_link
);
815 extern const struct dynamic_prop
*objfile_lookup_static_link
816 (struct objfile
*objfile
, const struct block
*block
);
818 #endif /* !defined (OBJFILES_H) */