1 /* Definitions for symbol file management in GDB.
3 Copyright 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
4 2001, 2002 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 2 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, write to the Free Software
20 Foundation, Inc., 59 Temple Place - Suite 330,
21 Boston, MA 02111-1307, USA. */
23 #if !defined (OBJFILES_H)
26 #include "gdb_obstack.h" /* For obstack internals. */
27 #include "symfile.h" /* For struct psymbol_allocation_list */
31 /* This structure maintains information on a per-objfile basis about the
32 "entry point" of the objfile, and the scope within which the entry point
33 exists. It is possible that gdb will see more than one objfile that is
34 executable, each with its own entry point.
36 For example, for dynamically linked executables in SVR4, the dynamic linker
37 code is contained within the shared C library, which is actually executable
38 and is run by the kernel first when an exec is done of a user executable
39 that is dynamically linked. The dynamic linker within the shared C library
40 then maps in the various program segments in the user executable and jumps
41 to the user executable's recorded entry point, as if the call had been made
42 directly by the kernel.
44 The traditional gdb method of using this info is to use the recorded entry
45 point to set the variables entry_file_lowpc and entry_file_highpc from
46 the debugging information, where these values are the starting address
47 (inclusive) and ending address (exclusive) of the instruction space in the
48 executable which correspond to the "startup file", I.E. crt0.o in most
49 cases. This file is assumed to be a startup file and frames with pc's
50 inside it are treated as nonexistent. Setting these variables is necessary
51 so that backtraces do not fly off the bottom of the stack.
53 Gdb also supports an alternate method to avoid running off the bottom
56 There are two frames that are "special", the frame for the function
57 containing the process entry point, since it has no predecessor frame,
58 and the frame for the function containing the user code entry point
59 (the main() function), since all the predecessor frames are for the
60 process startup code. Since we have no guarantee that the linked
61 in startup modules have any debugging information that gdb can use,
62 we need to avoid following frame pointers back into frames that might
63 have been built in the startup code, as we might get hopelessly
64 confused. However, we almost always have debugging information
67 These variables are used to save the range of PC values which are valid
68 within the main() function and within the function containing the process
69 entry point. If we always consider the frame for main() as the outermost
70 frame when debugging user code, and the frame for the process entry
71 point function as the outermost frame when debugging startup code, then
72 all we have to do is have FRAME_CHAIN_VALID return false whenever a
73 frame's current PC is within the range specified by these variables.
74 In essence, we set "ceilings" in the frame chain beyond which we will
75 not proceed when following the frame chain back up the stack.
77 A nice side effect is that we can still debug startup code without
78 running off the end of the frame chain, assuming that we have usable
79 debugging information in the startup modules, and if we choose to not
80 use the block at main, or can't find it for some reason, everything
81 still works as before. And if we have no startup code debugging
82 information but we do have usable information for main(), backtraces
83 from user code don't go wandering off into the startup code.
85 To use this method, define your FRAME_CHAIN_VALID macro like:
87 #define FRAME_CHAIN_VALID(chain, thisframe) \
89 && !(inside_main_func ((thisframe)->pc)) \
90 && !(inside_entry_func ((thisframe)->pc)))
92 and add initializations of the four scope controlling variables inside
93 the object file / debugging information processing modules. */
98 /* The value we should use for this objects entry point.
99 The illegal/unknown value needs to be something other than 0, ~0
100 for instance, which is much less likely than 0. */
102 CORE_ADDR entry_point
;
104 #define INVALID_ENTRY_POINT (~0) /* ~0 will not be in any file, we hope. */
106 /* Start (inclusive) and end (exclusive) of function containing the
109 CORE_ADDR entry_func_lowpc
;
110 CORE_ADDR entry_func_highpc
;
112 /* Start (inclusive) and end (exclusive) of object file containing the
115 CORE_ADDR entry_file_lowpc
;
116 CORE_ADDR entry_file_highpc
;
118 /* Start (inclusive) and end (exclusive) of the user code main() function. */
120 CORE_ADDR main_func_lowpc
;
121 CORE_ADDR main_func_highpc
;
123 /* Use these values when any of the above ranges is invalid. */
125 /* We use these values because it guarantees that there is no number that is
126 both >= LOWPC && < HIGHPC. It is also highly unlikely that 3 is a valid
127 module or function start address (as opposed to 0). */
129 #define INVALID_ENTRY_LOWPC (3)
130 #define INVALID_ENTRY_HIGHPC (1)
134 /* Sections in an objfile.
136 It is strange that we have both this notion of "sections"
137 and the one used by section_offsets. Section as used
138 here, (currently at least) means a BFD section, and the sections
139 are set up from the BFD sections in allocate_objfile.
141 The sections in section_offsets have their meaning determined by
142 the symbol format, and they are set up by the sym_offsets function
143 for that symbol file format.
145 I'm not sure this could or should be changed, however. */
149 CORE_ADDR addr
; /* lowest address in section */
150 CORE_ADDR endaddr
; /* 1+highest address in section */
152 /* This field is being used for nefarious purposes by syms_from_objfile.
153 It is said to be redundant with section_offsets; it's not really being
154 used that way, however, it's some sort of hack I don't understand
155 and am not going to try to eliminate (yet, anyway). FIXME.
157 It was documented as "offset between (end)addr and actual memory
158 addresses", but that's not true; addr & endaddr are actual memory
162 sec_ptr the_bfd_section
; /* BFD section pointer */
164 /* Objfile this section is part of. */
165 struct objfile
*objfile
;
167 /* True if this "overlay section" is mapped into an "overlay region". */
171 /* An import entry contains information about a symbol that
172 is used in this objfile but not defined in it, and so needs
173 to be imported from some other objfile */
174 /* Currently we just store the name; no attributes. 1997-08-05 */
175 typedef char *ImportEntry
;
178 /* An export entry contains information about a symbol that
179 is defined in this objfile and available for use in other
183 char *name
; /* name of exported symbol */
184 int address
; /* offset subject to relocation */
185 /* Currently no other attributes 1997-08-05 */
190 /* The "objstats" structure provides a place for gdb to record some
191 interesting information about its internal state at runtime, on a
192 per objfile basis, such as information about the number of symbols
193 read, size of string table (if any), etc. */
197 int n_minsyms
; /* Number of minimal symbols read */
198 int n_psyms
; /* Number of partial symbols read */
199 int n_syms
; /* Number of full symbols read */
200 int n_stabs
; /* Number of ".stabs" read (if applicable) */
201 int n_types
; /* Number of types */
202 int sz_strtab
; /* Size of stringtable, (if applicable) */
205 #define OBJSTAT(objfile, expr) (objfile -> stats.expr)
206 #define OBJSTATS struct objstats stats
207 extern void print_objfile_statistics (void);
208 extern void print_symbol_bcache_statistics (void);
210 /* Number of entries in the minimal symbol hash table. */
211 #define MINIMAL_SYMBOL_HASH_SIZE 2039
213 /* Master structure for keeping track of each file from which
214 gdb reads symbols. There are several ways these get allocated: 1.
215 The main symbol file, symfile_objfile, set by the symbol-file command,
216 2. Additional symbol files added by the add-symbol-file command,
217 3. Shared library objfiles, added by ADD_SOLIB, 4. symbol files
218 for modules that were loaded when GDB attached to a remote system
219 (see remote-vx.c). */
224 /* All struct objfile's are chained together by their next pointers.
225 The global variable "object_files" points to the first link in this
228 FIXME: There is a problem here if the objfile is reusable, and if
229 multiple users are to be supported. The problem is that the objfile
230 list is linked through a member of the objfile struct itself, which
231 is only valid for one gdb process. The list implementation needs to
232 be changed to something like:
234 struct list {struct list *next; struct objfile *objfile};
236 where the list structure is completely maintained separately within
239 struct objfile
*next
;
241 /* The object file's name, tilde-expanded and absolute.
242 Malloc'd; free it if you free this struct. */
246 /* Some flag bits for this objfile. */
248 unsigned short flags
;
250 /* Each objfile points to a linked list of symtabs derived from this file,
251 one symtab structure for each compilation unit (source file). Each link
252 in the symtab list contains a backpointer to this objfile. */
254 struct symtab
*symtabs
;
256 /* Each objfile points to a linked list of partial symtabs derived from
257 this file, one partial symtab structure for each compilation unit
260 struct partial_symtab
*psymtabs
;
262 /* List of freed partial symtabs, available for re-use */
264 struct partial_symtab
*free_psymtabs
;
266 /* The object file's BFD. Can be null if the objfile contains only
267 minimal symbols, e.g. the run time common symbols for SunOS4. */
271 /* The modification timestamp of the object file, as of the last time
272 we read its symbols. */
276 /* Obstacks to hold objects that should be freed when we load a new symbol
277 table from this object file. */
279 struct obstack psymbol_obstack
; /* Partial symbols */
280 struct obstack symbol_obstack
; /* Full symbols */
281 struct obstack type_obstack
; /* Types */
283 /* A byte cache where we can stash arbitrary "chunks" of bytes that
286 struct bcache
*psymbol_cache
; /* Byte cache for partial syms */
287 struct bcache
*macro_cache
; /* Byte cache for macros */
289 /* Vectors of all partial symbols read in from file. The actual data
290 is stored in the psymbol_obstack. */
292 struct psymbol_allocation_list global_psymbols
;
293 struct psymbol_allocation_list static_psymbols
;
295 /* Each file contains a pointer to an array of minimal symbols for all
296 global symbols that are defined within the file. The array is terminated
297 by a "null symbol", one that has a NULL pointer for the name and a zero
298 value for the address. This makes it easy to walk through the array
299 when passed a pointer to somewhere in the middle of it. There is also
300 a count of the number of symbols, which does not include the terminating
301 null symbol. The array itself, as well as all the data that it points
302 to, should be allocated on the symbol_obstack for this file. */
304 struct minimal_symbol
*msymbols
;
305 int minimal_symbol_count
;
307 /* This is a hash table used to index the minimal symbols by name. */
309 struct minimal_symbol
*msymbol_hash
[MINIMAL_SYMBOL_HASH_SIZE
];
311 /* This hash table is used to index the minimal symbols by their
314 struct minimal_symbol
*msymbol_demangled_hash
[MINIMAL_SYMBOL_HASH_SIZE
];
316 /* For object file formats which don't specify fundamental types, gdb
317 can create such types. For now, it maintains a vector of pointers
318 to these internally created fundamental types on a per objfile basis,
319 however it really should ultimately keep them on a per-compilation-unit
320 basis, to account for linkage-units that consist of a number of
321 compilation units that may have different fundamental types, such as
322 linking C modules with ADA modules, or linking C modules that are
323 compiled with 32-bit ints with C modules that are compiled with 64-bit
324 ints (not inherently evil with a smarter linker). */
326 struct type
**fundamental_types
;
328 /* The mmalloc() malloc-descriptor for this objfile if we are using
329 the memory mapped malloc() package to manage storage for this objfile's
330 data. NULL if we are not. */
334 /* The file descriptor that was used to obtain the mmalloc descriptor
335 for this objfile. If we call mmalloc_detach with the malloc descriptor
336 we should then close this file descriptor. */
340 /* Structure which keeps track of functions that manipulate objfile's
341 of the same type as this objfile. I.E. the function to read partial
342 symbols for example. Note that this structure is in statically
343 allocated memory, and is shared by all objfiles that use the
344 object module reader of this type. */
348 /* The per-objfile information about the entry point, the scope (file/func)
349 containing the entry point, and the scope of the user's main() func. */
351 struct entry_info ei
;
353 /* Information about stabs. Will be filled in with a dbx_symfile_info
354 struct by those readers that need it. */
356 struct dbx_symfile_info
*sym_stab_info
;
358 /* Hook for information for use by the symbol reader (currently used
359 for information shared by sym_init and sym_read). It is
360 typically a pointer to malloc'd memory. The symbol reader's finish
361 function is responsible for freeing the memory thusly allocated. */
365 /* Hook for target-architecture-specific information. This must
366 point to memory allocated on one of the obstacks in this objfile,
367 so that it gets freed automatically when reading a new object
372 /* Set of relocation offsets to apply to each section.
373 Currently on the psymbol_obstack (which makes no sense, but I'm
374 not sure it's harming anything).
376 These offsets indicate that all symbols (including partial and
377 minimal symbols) which have been read have been relocated by this
378 much. Symbols which are yet to be read need to be relocated by
381 struct section_offsets
*section_offsets
;
384 /* Indexes in the section_offsets array. These are initialized by the
385 *_symfile_offsets() family of functions (som_symfile_offsets,
386 xcoff_symfile_offsets, default_symfile_offsets). In theory they
387 should correspond to the section indexes used by bfd for the
388 current objfile. The exception to this for the time being is the
394 int sect_index_rodata
;
396 /* These pointers are used to locate the section table, which
397 among other things, is used to map pc addresses into sections.
398 SECTIONS points to the first entry in the table, and
399 SECTIONS_END points to the first location past the last entry
400 in the table. Currently the table is stored on the
401 psymbol_obstack (which makes no sense, but I'm not sure it's
402 harming anything). */
405 *sections
, *sections_end
;
407 /* two auxiliary fields, used to hold the fp of separate symbol files */
410 /* Imported symbols */
411 ImportEntry
*import_list
;
412 int import_list_size
;
414 /* Exported symbols */
415 ExportEntry
*export_list
;
416 int export_list_size
;
418 /* Link to objfile that contains the debug symbols for this one.
419 One is loaded if this file has an debug link to an existing
420 debug file with the right checksum */
421 struct objfile
*separate_debug_objfile
;
423 /* If this is a separate debug object, this is used as a link to the
424 actual executable objfile. */
425 struct objfile
*separate_debug_objfile_backlink
;
427 /* Place to stash various statistics about this objfile */
431 /* Defines for the objfile flag word. */
433 /* Gdb can arrange to allocate storage for all objects related to a
434 particular objfile in a designated section of its address space,
435 managed at a low level by mmap() and using a special version of
436 malloc that handles malloc/free/realloc on top of the mmap() interface.
437 This allows the "internal gdb state" for a particular objfile to be
438 dumped to a gdb state file and subsequently reloaded at a later time. */
440 #define OBJF_MAPPED (1 << 0) /* Objfile data is mmap'd */
442 /* When using mapped/remapped predigested gdb symbol information, we need
443 a flag that indicates that we have previously done an initial symbol
444 table read from this particular objfile. We can't just look for the
445 absence of any of the three symbol tables (msymbols, psymtab, symtab)
446 because if the file has no symbols for example, none of these will
449 #define OBJF_SYMS (1 << 1) /* Have tried to read symbols */
451 /* When an object file has its functions reordered (currently Irix-5.2
452 shared libraries exhibit this behaviour), we will need an expensive
453 algorithm to locate a partial symtab or symtab via an address.
454 To avoid this penalty for normal object files, we use this flag,
455 whose setting is determined upon symbol table read in. */
457 #define OBJF_REORDERED (1 << 2) /* Functions are reordered */
459 /* Distinguish between an objfile for a shared library and a "vanilla"
460 objfile. (If not set, the objfile may still actually be a solib.
461 This can happen if the user created the objfile by using the
462 add-symbol-file command. GDB doesn't in that situation actually
463 check whether the file is a solib. Rather, the target's
464 implementation of the solib interface is responsible for setting
465 this flag when noticing solibs used by an inferior.) */
467 #define OBJF_SHARED (1 << 3) /* From a shared library */
469 /* User requested that this objfile be read in it's entirety. */
471 #define OBJF_READNOW (1 << 4) /* Immediate full read */
473 /* This objfile was created because the user explicitly caused it
474 (e.g., used the add-symbol-file command). This bit offers a way
475 for run_command to remove old objfile entries which are no longer
476 valid (i.e., are associated with an old inferior), but to preserve
477 ones that the user explicitly loaded via the add-symbol-file
480 #define OBJF_USERLOADED (1 << 5) /* User loaded */
482 /* The object file that the main symbol table was loaded from (e.g. the
483 argument to the "symbol-file" or "file" command). */
485 extern struct objfile
*symfile_objfile
;
487 /* The object file that contains the runtime common minimal symbols
488 for SunOS4. Note that this objfile has no associated BFD. */
490 extern struct objfile
*rt_common_objfile
;
492 /* When we need to allocate a new type, we need to know which type_obstack
493 to allocate the type on, since there is one for each objfile. The places
494 where types are allocated are deeply buried in function call hierarchies
495 which know nothing about objfiles, so rather than trying to pass a
496 particular objfile down to them, we just do an end run around them and
497 set current_objfile to be whatever objfile we expect to be using at the
498 time types are being allocated. For instance, when we start reading
499 symbols for a particular objfile, we set current_objfile to point to that
500 objfile, and when we are done, we set it back to NULL, to ensure that we
501 never put a type someplace other than where we are expecting to put it.
502 FIXME: Maybe we should review the entire type handling system and
503 see if there is a better way to avoid this problem. */
505 extern struct objfile
*current_objfile
;
507 /* All known objfiles are kept in a linked list. This points to the
508 root of this list. */
510 extern struct objfile
*object_files
;
512 /* Declarations for functions defined in objfiles.c */
514 extern struct objfile
*allocate_objfile (bfd
*, int);
516 extern int build_objfile_section_table (struct objfile
*);
518 extern void put_objfile_before (struct objfile
*, struct objfile
*);
520 extern void objfile_to_front (struct objfile
*);
522 extern void unlink_objfile (struct objfile
*);
524 extern void free_objfile (struct objfile
*);
526 extern struct cleanup
*make_cleanup_free_objfile (struct objfile
*);
528 extern void free_all_objfiles (void);
530 extern void objfile_relocate (struct objfile
*, struct section_offsets
*);
532 extern int have_partial_symbols (void);
534 extern int have_full_symbols (void);
536 /* This operation deletes all objfile entries that represent solibs that
537 weren't explicitly loaded by the user, via e.g., the add-symbol-file
540 extern void objfile_purge_solibs (void);
542 /* Functions for dealing with the minimal symbol table, really a misc
543 address<->symbol mapping for things we don't have debug symbols for. */
545 extern int have_minimal_symbols (void);
547 extern struct obj_section
*find_pc_section (CORE_ADDR pc
);
549 extern struct obj_section
*find_pc_sect_section (CORE_ADDR pc
,
552 extern int in_plt_section (CORE_ADDR
, char *);
554 extern int is_in_import_list (char *, struct objfile
*);
556 /* Traverse all object files. ALL_OBJFILES_SAFE works even if you delete
557 the objfile during the traversal. */
559 #define ALL_OBJFILES(obj) \
560 for ((obj) = object_files; (obj) != NULL; (obj) = (obj)->next)
562 #define ALL_OBJFILES_SAFE(obj,nxt) \
563 for ((obj) = object_files; \
564 (obj) != NULL? ((nxt)=(obj)->next,1) :0; \
567 /* Traverse all symtabs in one objfile. */
569 #define ALL_OBJFILE_SYMTABS(objfile, s) \
570 for ((s) = (objfile) -> symtabs; (s) != NULL; (s) = (s) -> next)
572 /* Traverse all psymtabs in one objfile. */
574 #define ALL_OBJFILE_PSYMTABS(objfile, p) \
575 for ((p) = (objfile) -> psymtabs; (p) != NULL; (p) = (p) -> next)
577 /* Traverse all minimal symbols in one objfile. */
579 #define ALL_OBJFILE_MSYMBOLS(objfile, m) \
580 for ((m) = (objfile) -> msymbols; SYMBOL_NAME(m) != NULL; (m)++)
582 /* Traverse all symtabs in all objfiles. */
584 #define ALL_SYMTABS(objfile, s) \
585 ALL_OBJFILES (objfile) \
586 ALL_OBJFILE_SYMTABS (objfile, s)
588 /* Traverse all psymtabs in all objfiles. */
590 #define ALL_PSYMTABS(objfile, p) \
591 ALL_OBJFILES (objfile) \
592 ALL_OBJFILE_PSYMTABS (objfile, p)
594 /* Traverse all minimal symbols in all objfiles. */
596 #define ALL_MSYMBOLS(objfile, m) \
597 ALL_OBJFILES (objfile) \
598 if ((objfile)->msymbols) \
599 ALL_OBJFILE_MSYMBOLS (objfile, m)
601 #define ALL_OBJFILE_OSECTIONS(objfile, osect) \
602 for (osect = objfile->sections; osect < objfile->sections_end; osect++)
604 #define ALL_OBJSECTIONS(objfile, osect) \
605 ALL_OBJFILES (objfile) \
606 ALL_OBJFILE_OSECTIONS (objfile, osect)
608 #define SECT_OFF_DATA(objfile) \
609 ((objfile->sect_index_data == -1) \
610 ? (internal_error (__FILE__, __LINE__, "sect_index_data not initialized"), -1) \
611 : objfile->sect_index_data)
613 #define SECT_OFF_RODATA(objfile) \
614 ((objfile->sect_index_rodata == -1) \
615 ? (internal_error (__FILE__, __LINE__, "sect_index_rodata not initialized"), -1) \
616 : objfile->sect_index_rodata)
618 #define SECT_OFF_TEXT(objfile) \
619 ((objfile->sect_index_text == -1) \
620 ? (internal_error (__FILE__, __LINE__, "sect_index_text not initialized"), -1) \
621 : objfile->sect_index_text)
623 /* Sometimes the .bss section is missing from the objfile, so we don't
624 want to die here. Let the users of SECT_OFF_BSS deal with an
625 uninitialized section index. */
626 #define SECT_OFF_BSS(objfile) (objfile)->sect_index_bss
628 #endif /* !defined (OBJFILES_H) */