1 /* Definitions for symbol file management in GDB.
3 Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001,
4 2002, 2003, 2004, 2007, 2008 Free Software Foundation, Inc.
6 This file is part of GDB.
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3 of the License, or
11 (at your option) any later version.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with this program. If not, see <http://www.gnu.org/licenses/>. */
21 #if !defined (OBJFILES_H)
24 #include "gdb_obstack.h" /* For obstack internals. */
25 #include "symfile.h" /* For struct psymbol_allocation_list */
32 /* This structure maintains information on a per-objfile basis about the
33 "entry point" of the objfile, and the scope within which the entry point
34 exists. It is possible that gdb will see more than one objfile that is
35 executable, each with its own entry point.
37 For example, for dynamically linked executables in SVR4, the dynamic linker
38 code is contained within the shared C library, which is actually executable
39 and is run by the kernel first when an exec is done of a user executable
40 that is dynamically linked. The dynamic linker within the shared C library
41 then maps in the various program segments in the user executable and jumps
42 to the user executable's recorded entry point, as if the call had been made
43 directly by the kernel.
45 The traditional gdb method of using this info was to use the
46 recorded entry point to set the entry-file's lowpc and highpc from
47 the debugging information, where these values are the starting
48 address (inclusive) and ending address (exclusive) of the
49 instruction space in the executable which correspond to the
50 "startup file", I.E. crt0.o in most cases. This file is assumed to
51 be a startup file and frames with pc's inside it are treated as
52 nonexistent. Setting these variables is necessary so that
53 backtraces do not fly off the bottom of the stack.
55 NOTE: cagney/2003-09-09: It turns out that this "traditional"
56 method doesn't work. Corinna writes: ``It turns out that the call
57 to test for "inside entry file" destroys a meaningful backtrace
58 under some conditions. E. g. the backtrace tests in the asm-source
59 testcase are broken for some targets. In this test the functions
60 are all implemented as part of one file and the testcase is not
61 necessarily linked with a start file (depending on the target).
62 What happens is, that the first frame is printed normaly and
63 following frames are treated as being inside the enttry file then.
64 This way, only the #0 frame is printed in the backtrace output.''
65 Ref "frame.c" "NOTE: vinschen/2003-04-01".
67 Gdb also supports an alternate method to avoid running off the bottom
70 There are two frames that are "special", the frame for the function
71 containing the process entry point, since it has no predecessor frame,
72 and the frame for the function containing the user code entry point
73 (the main() function), since all the predecessor frames are for the
74 process startup code. Since we have no guarantee that the linked
75 in startup modules have any debugging information that gdb can use,
76 we need to avoid following frame pointers back into frames that might
77 have been built in the startup code, as we might get hopelessly
78 confused. However, we almost always have debugging information
81 These variables are used to save the range of PC values which are
82 valid within the main() function and within the function containing
83 the process entry point. If we always consider the frame for
84 main() as the outermost frame when debugging user code, and the
85 frame for the process entry point function as the outermost frame
86 when debugging startup code, then all we have to do is have
87 DEPRECATED_FRAME_CHAIN_VALID return false whenever a frame's
88 current PC is within the range specified by these variables. In
89 essence, we set "ceilings" in the frame chain beyond which we will
90 not proceed when following the frame chain back up the stack.
92 A nice side effect is that we can still debug startup code without
93 running off the end of the frame chain, assuming that we have usable
94 debugging information in the startup modules, and if we choose to not
95 use the block at main, or can't find it for some reason, everything
96 still works as before. And if we have no startup code debugging
97 information but we do have usable information for main(), backtraces
98 from user code don't go wandering off into the startup code. */
103 /* The value we should use for this objects entry point.
104 The illegal/unknown value needs to be something other than 0, ~0
105 for instance, which is much less likely than 0. */
107 CORE_ADDR entry_point;
109 #define INVALID_ENTRY_POINT (~0) /* ~0 will not be in any file, we hope. */
113 /* Sections in an objfile.
115 It is strange that we have both this notion of "sections"
116 and the one used by section_offsets. Section as used
117 here, (currently at least) means a BFD section, and the sections
118 are set up from the BFD sections in allocate_objfile.
120 The sections in section_offsets have their meaning determined by
121 the symbol format, and they are set up by the sym_offsets function
122 for that symbol file format.
124 I'm not sure this could or should be changed, however. */
128 CORE_ADDR addr; /* lowest address in section */
129 CORE_ADDR endaddr; /* 1+highest address in section */
131 /* This field is being used for nefarious purposes by syms_from_objfile.
132 It is said to be redundant with section_offsets; it's not really being
133 used that way, however, it's some sort of hack I don't understand
134 and am not going to try to eliminate (yet, anyway). FIXME.
136 It was documented as "offset between (end)addr and actual memory
137 addresses", but that's not true; addr & endaddr are actual memory
141 struct bfd_section *the_bfd_section; /* BFD section pointer */
143 /* Objfile this section is part of. */
144 struct objfile *objfile;
146 /* True if this "overlay section" is mapped into an "overlay region". */
151 /* The "objstats" structure provides a place for gdb to record some
152 interesting information about its internal state at runtime, on a
153 per objfile basis, such as information about the number of symbols
154 read, size of string table (if any), etc. */
158 int n_minsyms; /* Number of minimal symbols read */
159 int n_psyms; /* Number of partial symbols read */
160 int n_syms; /* Number of full symbols read */
161 int n_stabs; /* Number of ".stabs" read (if applicable) */
162 int n_types; /* Number of types */
163 int sz_strtab; /* Size of stringtable, (if applicable) */
166 #define OBJSTAT(objfile, expr) (objfile -> stats.expr)
167 #define OBJSTATS struct objstats stats
168 extern void print_objfile_statistics (void);
169 extern void print_symbol_bcache_statistics (void);
171 /* Number of entries in the minimal symbol hash table. */
172 #define MINIMAL_SYMBOL_HASH_SIZE 2039
174 /* Master structure for keeping track of each file from which
175 gdb reads symbols. There are several ways these get allocated: 1.
176 The main symbol file, symfile_objfile, set by the symbol-file command,
177 2. Additional symbol files added by the add-symbol-file command,
178 3. Shared library objfiles, added by ADD_SOLIB, 4. symbol files
179 for modules that were loaded when GDB attached to a remote system
180 (see remote-vx.c). */
185 /* All struct objfile's are chained together by their next pointers.
186 The global variable "object_files" points to the first link in this
189 FIXME: There is a problem here if the objfile is reusable, and if
190 multiple users are to be supported. The problem is that the objfile
191 list is linked through a member of the objfile struct itself, which
192 is only valid for one gdb process. The list implementation needs to
193 be changed to something like:
195 struct list {struct list *next; struct objfile *objfile};
197 where the list structure is completely maintained separately within
200 struct objfile *next;
202 /* The object file's name, tilde-expanded and absolute.
203 Malloc'd; free it if you free this struct. */
207 /* Some flag bits for this objfile. */
209 unsigned short flags;
211 /* Each objfile points to a linked list of symtabs derived from this file,
212 one symtab structure for each compilation unit (source file). Each link
213 in the symtab list contains a backpointer to this objfile. */
215 struct symtab *symtabs;
217 /* Each objfile points to a linked list of partial symtabs derived from
218 this file, one partial symtab structure for each compilation unit
221 struct partial_symtab *psymtabs;
223 /* List of freed partial symtabs, available for re-use */
225 struct partial_symtab *free_psymtabs;
227 /* The object file's BFD. Can be null if the objfile contains only
228 minimal symbols, e.g. the run time common symbols for SunOS4. */
232 /* The gdbarch associated with the BFD. Note that this gdbarch is
233 determined solely from BFD information, without looking at target
234 information. The gdbarch determined from a running target may
235 differ from this e.g. with respect to register types and names. */
237 struct gdbarch *gdbarch;
239 /* The modification timestamp of the object file, as of the last time
240 we read its symbols. */
244 /* Obstack to hold objects that should be freed when we load a new symbol
245 table from this object file. */
247 struct obstack objfile_obstack;
249 /* A byte cache where we can stash arbitrary "chunks" of bytes that
252 struct bcache *psymbol_cache; /* Byte cache for partial syms */
253 struct bcache *macro_cache; /* Byte cache for macros */
255 /* Hash table for mapping symbol names to demangled names. Each
256 entry in the hash table is actually two consecutive strings,
257 both null-terminated; the first one is a mangled or linkage
258 name, and the second is the demangled name or just a zero byte
259 if the name doesn't demangle. */
260 struct htab *demangled_names_hash;
262 /* Vectors of all partial symbols read in from file. The actual data
263 is stored in the objfile_obstack. */
265 struct psymbol_allocation_list global_psymbols;
266 struct psymbol_allocation_list static_psymbols;
268 /* Each file contains a pointer to an array of minimal symbols for all
269 global symbols that are defined within the file. The array is terminated
270 by a "null symbol", one that has a NULL pointer for the name and a zero
271 value for the address. This makes it easy to walk through the array
272 when passed a pointer to somewhere in the middle of it. There is also
273 a count of the number of symbols, which does not include the terminating
274 null symbol. The array itself, as well as all the data that it points
275 to, should be allocated on the objfile_obstack for this file. */
277 struct minimal_symbol *msymbols;
278 int minimal_symbol_count;
280 /* This is a hash table used to index the minimal symbols by name. */
282 struct minimal_symbol *msymbol_hash[MINIMAL_SYMBOL_HASH_SIZE];
284 /* This hash table is used to index the minimal symbols by their
287 struct minimal_symbol *msymbol_demangled_hash[MINIMAL_SYMBOL_HASH_SIZE];
289 /* The mmalloc() malloc-descriptor for this objfile if we are using
290 the memory mapped malloc() package to manage storage for this objfile's
291 data. NULL if we are not. */
295 /* The file descriptor that was used to obtain the mmalloc descriptor
296 for this objfile. If we call mmalloc_detach with the malloc descriptor
297 we should then close this file descriptor. */
301 /* Structure which keeps track of functions that manipulate objfile's
302 of the same type as this objfile. I.E. the function to read partial
303 symbols for example. Note that this structure is in statically
304 allocated memory, and is shared by all objfiles that use the
305 object module reader of this type. */
309 /* The per-objfile information about the entry point, the scope (file/func)
310 containing the entry point, and the scope of the user's main() func. */
312 struct entry_info ei;
314 /* Information about stabs. Will be filled in with a dbx_symfile_info
315 struct by those readers that need it. */
316 /* NOTE: cagney/2004-10-23: This has been replaced by per-objfile
317 data points implemented using "data" and "num_data" below. For
318 an example of how to use this replacement, see "objfile_data"
321 struct dbx_symfile_info *deprecated_sym_stab_info;
323 /* Hook for information for use by the symbol reader (currently used
324 for information shared by sym_init and sym_read). It is
325 typically a pointer to malloc'd memory. The symbol reader's finish
326 function is responsible for freeing the memory thusly allocated. */
327 /* NOTE: cagney/2004-10-23: This has been replaced by per-objfile
328 data points implemented using "data" and "num_data" below. For
329 an example of how to use this replacement, see "objfile_data"
332 void *deprecated_sym_private;
334 /* Hook for target-architecture-specific information. This must
335 point to memory allocated on one of the obstacks in this objfile,
336 so that it gets freed automatically when reading a new object
339 void *deprecated_obj_private;
341 /* Per objfile data-pointers required by other GDB modules. */
342 /* FIXME: kettenis/20030711: This mechanism could replace
343 deprecated_sym_stab_info, deprecated_sym_private and
344 deprecated_obj_private entirely. */
349 /* Set of relocation offsets to apply to each section.
350 Currently on the objfile_obstack (which makes no sense, but I'm
351 not sure it's harming anything).
353 These offsets indicate that all symbols (including partial and
354 minimal symbols) which have been read have been relocated by this
355 much. Symbols which are yet to be read need to be relocated by
358 struct section_offsets *section_offsets;
361 /* Indexes in the section_offsets array. These are initialized by the
362 *_symfile_offsets() family of functions (som_symfile_offsets,
363 xcoff_symfile_offsets, default_symfile_offsets). In theory they
364 should correspond to the section indexes used by bfd for the
365 current objfile. The exception to this for the time being is the
371 int sect_index_rodata;
373 /* These pointers are used to locate the section table, which
374 among other things, is used to map pc addresses into sections.
375 SECTIONS points to the first entry in the table, and
376 SECTIONS_END points to the first location past the last entry
377 in the table. Currently the table is stored on the
378 objfile_obstack (which makes no sense, but I'm not sure it's
379 harming anything). */
382 *sections, *sections_end;
384 /* Link to objfile that contains the debug symbols for this one.
385 One is loaded if this file has an debug link to an existing
386 debug file with the right checksum */
387 struct objfile *separate_debug_objfile;
389 /* If this is a separate debug object, this is used as a link to the
390 actual executable objfile. */
391 struct objfile *separate_debug_objfile_backlink;
393 /* Place to stash various statistics about this objfile */
396 /* A symtab that the C++ code uses to stash special symbols
397 associated to namespaces. */
399 /* FIXME/carlton-2003-06-27: Delete this in a few years once
400 "possible namespace symbols" go away. */
401 struct symtab *cp_namespace_symtab;
404 /* Defines for the objfile flag word. */
406 /* When using mapped/remapped predigested gdb symbol information, we need
407 a flag that indicates that we have previously done an initial symbol
408 table read from this particular objfile. We can't just look for the
409 absence of any of the three symbol tables (msymbols, psymtab, symtab)
410 because if the file has no symbols for example, none of these will
413 #define OBJF_SYMS (1 << 1) /* Have tried to read symbols */
415 /* When an object file has its functions reordered (currently Irix-5.2
416 shared libraries exhibit this behaviour), we will need an expensive
417 algorithm to locate a partial symtab or symtab via an address.
418 To avoid this penalty for normal object files, we use this flag,
419 whose setting is determined upon symbol table read in. */
421 #define OBJF_REORDERED (1 << 2) /* Functions are reordered */
423 /* Distinguish between an objfile for a shared library and a "vanilla"
424 objfile. (If not set, the objfile may still actually be a solib.
425 This can happen if the user created the objfile by using the
426 add-symbol-file command. GDB doesn't in that situation actually
427 check whether the file is a solib. Rather, the target's
428 implementation of the solib interface is responsible for setting
429 this flag when noticing solibs used by an inferior.) */
431 #define OBJF_SHARED (1 << 3) /* From a shared library */
433 /* User requested that this objfile be read in it's entirety. */
435 #define OBJF_READNOW (1 << 4) /* Immediate full read */
437 /* This objfile was created because the user explicitly caused it
438 (e.g., used the add-symbol-file command). This bit offers a way
439 for run_command to remove old objfile entries which are no longer
440 valid (i.e., are associated with an old inferior), but to preserve
441 ones that the user explicitly loaded via the add-symbol-file
444 #define OBJF_USERLOADED (1 << 5) /* User loaded */
446 /* The object file that the main symbol table was loaded from (e.g. the
447 argument to the "symbol-file" or "file" command). */
449 extern struct objfile *symfile_objfile;
451 /* The object file that contains the runtime common minimal symbols
452 for SunOS4. Note that this objfile has no associated BFD. */
454 extern struct objfile *rt_common_objfile;
456 /* When we need to allocate a new type, we need to know which objfile_obstack
457 to allocate the type on, since there is one for each objfile. The places
458 where types are allocated are deeply buried in function call hierarchies
459 which know nothing about objfiles, so rather than trying to pass a
460 particular objfile down to them, we just do an end run around them and
461 set current_objfile to be whatever objfile we expect to be using at the
462 time types are being allocated. For instance, when we start reading
463 symbols for a particular objfile, we set current_objfile to point to that
464 objfile, and when we are done, we set it back to NULL, to ensure that we
465 never put a type someplace other than where we are expecting to put it.
466 FIXME: Maybe we should review the entire type handling system and
467 see if there is a better way to avoid this problem. */
469 extern struct objfile *current_objfile;
471 /* All known objfiles are kept in a linked list. This points to the
472 root of this list. */
474 extern struct objfile *object_files;
476 /* Declarations for functions defined in objfiles.c */
478 extern struct objfile *allocate_objfile (bfd *, int);
480 extern struct gdbarch *get_objfile_arch (struct objfile *);
482 extern void init_entry_point_info (struct objfile *);
484 extern CORE_ADDR entry_point_address (void);
486 extern int build_objfile_section_table (struct objfile *);
488 extern void terminate_minimal_symbol_table (struct objfile *objfile);
490 extern void put_objfile_before (struct objfile *, struct objfile *);
492 extern void objfile_to_front (struct objfile *);
494 extern void unlink_objfile (struct objfile *);
496 extern void free_objfile (struct objfile *);
498 extern struct cleanup *make_cleanup_free_objfile (struct objfile *);
500 extern void free_all_objfiles (void);
502 extern void objfile_relocate (struct objfile *, struct section_offsets *);
504 extern int have_partial_symbols (void);
506 extern int have_full_symbols (void);
508 /* This operation deletes all objfile entries that represent solibs that
509 weren't explicitly loaded by the user, via e.g., the add-symbol-file
512 extern void objfile_purge_solibs (void);
514 /* Functions for dealing with the minimal symbol table, really a misc
515 address<->symbol mapping for things we don't have debug symbols for. */
517 extern int have_minimal_symbols (void);
519 extern struct obj_section *find_pc_section (CORE_ADDR pc);
521 extern struct obj_section *find_pc_sect_section (CORE_ADDR pc,
524 extern int in_plt_section (CORE_ADDR, char *);
526 /* Keep a registry of per-objfile data-pointers required by other GDB
529 extern const struct objfile_data *register_objfile_data (void);
530 extern const struct objfile_data *register_objfile_data_with_cleanup
531 (void (*cleanup) (struct objfile *, void *));
532 extern void clear_objfile_data (struct objfile *objfile);
533 extern void set_objfile_data (struct objfile *objfile,
534 const struct objfile_data *data, void *value);
535 extern void *objfile_data (struct objfile *objfile,
536 const struct objfile_data *data);
539 /* Traverse all object files. ALL_OBJFILES_SAFE works even if you delete
540 the objfile during the traversal. */
542 #define ALL_OBJFILES(obj) \
543 for ((obj) = object_files; (obj) != NULL; (obj) = (obj)->next)
545 #define ALL_OBJFILES_SAFE(obj,nxt) \
546 for ((obj) = object_files; \
547 (obj) != NULL? ((nxt)=(obj)->next,1) :0; \
550 /* Traverse all symtabs in one objfile. */
552 #define ALL_OBJFILE_SYMTABS(objfile, s) \
553 for ((s) = (objfile) -> symtabs; (s) != NULL; (s) = (s) -> next)
555 /* Traverse all psymtabs in one objfile. */
557 #define ALL_OBJFILE_PSYMTABS(objfile, p) \
558 for ((p) = (objfile) -> psymtabs; (p) != NULL; (p) = (p) -> next)
560 /* Traverse all minimal symbols in one objfile. */
562 #define ALL_OBJFILE_MSYMBOLS(objfile, m) \
563 for ((m) = (objfile) -> msymbols; DEPRECATED_SYMBOL_NAME(m) != NULL; (m)++)
565 /* Traverse all symtabs in all objfiles. */
567 #define ALL_SYMTABS(objfile, s) \
568 ALL_OBJFILES (objfile) \
569 ALL_OBJFILE_SYMTABS (objfile, s)
571 /* Traverse all symtabs in all objfiles, skipping included files
572 (which share a blockvector with their primary symtab). */
574 #define ALL_PRIMARY_SYMTABS(objfile, s) \
575 ALL_OBJFILES (objfile) \
576 ALL_OBJFILE_SYMTABS (objfile, s) \
579 /* Traverse all psymtabs in all objfiles. */
581 #define ALL_PSYMTABS(objfile, p) \
582 ALL_OBJFILES (objfile) \
583 ALL_OBJFILE_PSYMTABS (objfile, p)
585 /* Traverse all minimal symbols in all objfiles. */
587 #define ALL_MSYMBOLS(objfile, m) \
588 ALL_OBJFILES (objfile) \
589 ALL_OBJFILE_MSYMBOLS (objfile, m)
591 #define ALL_OBJFILE_OSECTIONS(objfile, osect) \
592 for (osect = objfile->sections; osect < objfile->sections_end; osect++)
594 #define ALL_OBJSECTIONS(objfile, osect) \
595 ALL_OBJFILES (objfile) \
596 ALL_OBJFILE_OSECTIONS (objfile, osect)
598 #define SECT_OFF_DATA(objfile) \
599 ((objfile->sect_index_data == -1) \
600 ? (internal_error (__FILE__, __LINE__, _("sect_index_data not initialized")), -1) \
601 : objfile->sect_index_data)
603 #define SECT_OFF_RODATA(objfile) \
604 ((objfile->sect_index_rodata == -1) \
605 ? (internal_error (__FILE__, __LINE__, _("sect_index_rodata not initialized")), -1) \
606 : objfile->sect_index_rodata)
608 #define SECT_OFF_TEXT(objfile) \
609 ((objfile->sect_index_text == -1) \
610 ? (internal_error (__FILE__, __LINE__, _("sect_index_text not initialized")), -1) \
611 : objfile->sect_index_text)
613 /* Sometimes the .bss section is missing from the objfile, so we don't
614 want to die here. Let the users of SECT_OFF_BSS deal with an
615 uninitialized section index. */
616 #define SECT_OFF_BSS(objfile) (objfile)->sect_index_bss
618 #endif /* !defined (OBJFILES_H) */