1 /* Definitions for symbol file management in GDB.
3 Copyright 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
4 2001, 2002, 2003 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 */
33 /* This structure maintains information on a per-objfile basis about the
34 "entry point" of the objfile, and the scope within which the entry point
35 exists. It is possible that gdb will see more than one objfile that is
36 executable, each with its own entry point.
38 For example, for dynamically linked executables in SVR4, the dynamic linker
39 code is contained within the shared C library, which is actually executable
40 and is run by the kernel first when an exec is done of a user executable
41 that is dynamically linked. The dynamic linker within the shared C library
42 then maps in the various program segments in the user executable and jumps
43 to the user executable's recorded entry point, as if the call had been made
44 directly by the kernel.
46 The traditional gdb method of using this info is to use the
47 recorded entry point to set the variables
48 deprecated_entry_file_lowpc and deprecated_entry_file_highpc from
49 the debugging information, where these values are the starting
50 address (inclusive) and ending address (exclusive) of the
51 instruction space in the executable which correspond to the
52 "startup file", I.E. crt0.o in most cases. This file is assumed to
53 be a startup file and frames with pc's inside it are treated as
54 nonexistent. Setting these variables is necessary so that
55 backtraces do not fly off the bottom of the stack.
57 NOTE: cagney/2003-09-09: It turns out that this "traditional"
58 method doesn't work. Corinna writes: ``It turns out that the call
59 to deprecated_inside_entry_file destroys a meaningful backtrace
60 under some conditions. E. g. the backtrace tests in the asm-source
61 testcase are broken for some targets. In this test the functions
62 are all implemented as part of one file and the testcase is not
63 necessarily linked with a start file (depending on the target).
64 What happens is, that the first frame is printed normaly and
65 following frames are treated as being inside the enttry file then.
66 This way, only the #0 frame is printed in the backtrace output.''
67 Ref "frame.c" "NOTE: vinschen/2003-04-01".
69 Gdb also supports an alternate method to avoid running off the bottom
72 There are two frames that are "special", the frame for the function
73 containing the process entry point, since it has no predecessor frame,
74 and the frame for the function containing the user code entry point
75 (the main() function), since all the predecessor frames are for the
76 process startup code. Since we have no guarantee that the linked
77 in startup modules have any debugging information that gdb can use,
78 we need to avoid following frame pointers back into frames that might
79 have been built in the startup code, as we might get hopelessly
80 confused. However, we almost always have debugging information
83 These variables are used to save the range of PC values which are
84 valid within the main() function and within the function containing
85 the process entry point. If we always consider the frame for
86 main() as the outermost frame when debugging user code, and the
87 frame for the process entry point function as the outermost frame
88 when debugging startup code, then all we have to do is have
89 DEPRECATED_FRAME_CHAIN_VALID return false whenever a frame's
90 current PC is within the range specified by these variables. In
91 essence, we set "ceilings" in the frame chain beyond which we will
92 not proceed when following the frame chain back up the stack.
94 A nice side effect is that we can still debug startup code without
95 running off the end of the frame chain, assuming that we have usable
96 debugging information in the startup modules, and if we choose to not
97 use the block at main, or can't find it for some reason, everything
98 still works as before. And if we have no startup code debugging
99 information but we do have usable information for main(), backtraces
100 from user code don't go wandering off into the startup code.
102 To use this method, define your DEPRECATED_FRAME_CHAIN_VALID macro
105 #define DEPRECATED_FRAME_CHAIN_VALID(chain, thisframe) \
107 && !(inside_main_func ((thisframe)->pc)) \
108 && !(inside_entry_func ((thisframe)->pc)))
110 and add initializations of the four scope controlling variables inside
111 the object file / debugging information processing modules. */
116 /* The value we should use for this objects entry point.
117 The illegal/unknown value needs to be something other than 0, ~0
118 for instance, which is much less likely than 0. */
120 CORE_ADDR entry_point
;
122 #define INVALID_ENTRY_POINT (~0) /* ~0 will not be in any file, we hope. */
124 /* Start (inclusive) and end (exclusive) of function containing the
127 CORE_ADDR entry_func_lowpc
;
128 CORE_ADDR entry_func_highpc
;
130 /* Start (inclusive) and end (exclusive) of object file containing the
133 CORE_ADDR deprecated_entry_file_lowpc
;
134 CORE_ADDR deprecated_entry_file_highpc
;
136 /* Start (inclusive) and end (exclusive) of the user code main() function. */
138 CORE_ADDR main_func_lowpc
;
139 CORE_ADDR main_func_highpc
;
141 /* Use these values when any of the above ranges is invalid. */
143 /* We use these values because it guarantees that there is no number that is
144 both >= LOWPC && < HIGHPC. It is also highly unlikely that 3 is a valid
145 module or function start address (as opposed to 0). */
147 #define INVALID_ENTRY_LOWPC (3)
148 #define INVALID_ENTRY_HIGHPC (1)
152 /* Sections in an objfile.
154 It is strange that we have both this notion of "sections"
155 and the one used by section_offsets. Section as used
156 here, (currently at least) means a BFD section, and the sections
157 are set up from the BFD sections in allocate_objfile.
159 The sections in section_offsets have their meaning determined by
160 the symbol format, and they are set up by the sym_offsets function
161 for that symbol file format.
163 I'm not sure this could or should be changed, however. */
167 CORE_ADDR addr
; /* lowest address in section */
168 CORE_ADDR endaddr
; /* 1+highest address in section */
170 /* This field is being used for nefarious purposes by syms_from_objfile.
171 It is said to be redundant with section_offsets; it's not really being
172 used that way, however, it's some sort of hack I don't understand
173 and am not going to try to eliminate (yet, anyway). FIXME.
175 It was documented as "offset between (end)addr and actual memory
176 addresses", but that's not true; addr & endaddr are actual memory
180 sec_ptr the_bfd_section
; /* BFD section pointer */
182 /* Objfile this section is part of. */
183 struct objfile
*objfile
;
185 /* True if this "overlay section" is mapped into an "overlay region". */
189 /* An import entry contains information about a symbol that
190 is used in this objfile but not defined in it, and so needs
191 to be imported from some other objfile */
192 /* Currently we just store the name; no attributes. 1997-08-05 */
193 typedef char *ImportEntry
;
196 /* An export entry contains information about a symbol that
197 is defined in this objfile and available for use in other
201 char *name
; /* name of exported symbol */
202 int address
; /* offset subject to relocation */
203 /* Currently no other attributes 1997-08-05 */
208 /* The "objstats" structure provides a place for gdb to record some
209 interesting information about its internal state at runtime, on a
210 per objfile basis, such as information about the number of symbols
211 read, size of string table (if any), etc. */
215 int n_minsyms
; /* Number of minimal symbols read */
216 int n_psyms
; /* Number of partial symbols read */
217 int n_syms
; /* Number of full symbols read */
218 int n_stabs
; /* Number of ".stabs" read (if applicable) */
219 int n_types
; /* Number of types */
220 int sz_strtab
; /* Size of stringtable, (if applicable) */
223 #define OBJSTAT(objfile, expr) (objfile -> stats.expr)
224 #define OBJSTATS struct objstats stats
225 extern void print_objfile_statistics (void);
226 extern void print_symbol_bcache_statistics (void);
228 /* Number of entries in the minimal symbol hash table. */
229 #define MINIMAL_SYMBOL_HASH_SIZE 2039
231 /* Master structure for keeping track of each file from which
232 gdb reads symbols. There are several ways these get allocated: 1.
233 The main symbol file, symfile_objfile, set by the symbol-file command,
234 2. Additional symbol files added by the add-symbol-file command,
235 3. Shared library objfiles, added by ADD_SOLIB, 4. symbol files
236 for modules that were loaded when GDB attached to a remote system
237 (see remote-vx.c). */
242 /* All struct objfile's are chained together by their next pointers.
243 The global variable "object_files" points to the first link in this
246 FIXME: There is a problem here if the objfile is reusable, and if
247 multiple users are to be supported. The problem is that the objfile
248 list is linked through a member of the objfile struct itself, which
249 is only valid for one gdb process. The list implementation needs to
250 be changed to something like:
252 struct list {struct list *next; struct objfile *objfile};
254 where the list structure is completely maintained separately within
257 struct objfile
*next
;
259 /* The object file's name, tilde-expanded and absolute.
260 Malloc'd; free it if you free this struct. */
264 /* Some flag bits for this objfile. */
266 unsigned short flags
;
268 /* Each objfile points to a linked list of symtabs derived from this file,
269 one symtab structure for each compilation unit (source file). Each link
270 in the symtab list contains a backpointer to this objfile. */
272 struct symtab
*symtabs
;
274 /* Each objfile points to a linked list of partial symtabs derived from
275 this file, one partial symtab structure for each compilation unit
278 struct partial_symtab
*psymtabs
;
280 /* List of freed partial symtabs, available for re-use */
282 struct partial_symtab
*free_psymtabs
;
284 /* The object file's BFD. Can be null if the objfile contains only
285 minimal symbols, e.g. the run time common symbols for SunOS4. */
289 /* The modification timestamp of the object file, as of the last time
290 we read its symbols. */
294 /* Obstacks to hold objects that should be freed when we load a new symbol
295 table from this object file. */
297 struct obstack psymbol_obstack
; /* Partial symbols */
298 struct obstack symbol_obstack
; /* Full symbols */
299 struct obstack type_obstack
; /* Types */
301 /* A byte cache where we can stash arbitrary "chunks" of bytes that
304 struct bcache
*psymbol_cache
; /* Byte cache for partial syms */
305 struct bcache
*macro_cache
; /* Byte cache for macros */
307 /* Hash table for mapping symbol names to demangled names. Each
308 entry in the hash table is actually two consecutive strings,
309 both null-terminated; the first one is a mangled or linkage
310 name, and the second is the demangled name or just a zero byte
311 if the name doesn't demangle. */
312 struct htab
*demangled_names_hash
;
314 /* Vectors of all partial symbols read in from file. The actual data
315 is stored in the psymbol_obstack. */
317 struct psymbol_allocation_list global_psymbols
;
318 struct psymbol_allocation_list static_psymbols
;
320 /* Each file contains a pointer to an array of minimal symbols for all
321 global symbols that are defined within the file. The array is terminated
322 by a "null symbol", one that has a NULL pointer for the name and a zero
323 value for the address. This makes it easy to walk through the array
324 when passed a pointer to somewhere in the middle of it. There is also
325 a count of the number of symbols, which does not include the terminating
326 null symbol. The array itself, as well as all the data that it points
327 to, should be allocated on the symbol_obstack for this file. */
329 struct minimal_symbol
*msymbols
;
330 int minimal_symbol_count
;
332 /* This is a hash table used to index the minimal symbols by name. */
334 struct minimal_symbol
*msymbol_hash
[MINIMAL_SYMBOL_HASH_SIZE
];
336 /* This hash table is used to index the minimal symbols by their
339 struct minimal_symbol
*msymbol_demangled_hash
[MINIMAL_SYMBOL_HASH_SIZE
];
341 /* For object file formats which don't specify fundamental types, gdb
342 can create such types. For now, it maintains a vector of pointers
343 to these internally created fundamental types on a per objfile basis,
344 however it really should ultimately keep them on a per-compilation-unit
345 basis, to account for linkage-units that consist of a number of
346 compilation units that may have different fundamental types, such as
347 linking C modules with ADA modules, or linking C modules that are
348 compiled with 32-bit ints with C modules that are compiled with 64-bit
349 ints (not inherently evil with a smarter linker). */
351 struct type
**fundamental_types
;
353 /* The mmalloc() malloc-descriptor for this objfile if we are using
354 the memory mapped malloc() package to manage storage for this objfile's
355 data. NULL if we are not. */
359 /* The file descriptor that was used to obtain the mmalloc descriptor
360 for this objfile. If we call mmalloc_detach with the malloc descriptor
361 we should then close this file descriptor. */
365 /* Structure which keeps track of functions that manipulate objfile's
366 of the same type as this objfile. I.E. the function to read partial
367 symbols for example. Note that this structure is in statically
368 allocated memory, and is shared by all objfiles that use the
369 object module reader of this type. */
373 /* The per-objfile information about the entry point, the scope (file/func)
374 containing the entry point, and the scope of the user's main() func. */
376 struct entry_info ei
;
378 /* Information about stabs. Will be filled in with a dbx_symfile_info
379 struct by those readers that need it. */
381 struct dbx_symfile_info
*sym_stab_info
;
383 /* Hook for information for use by the symbol reader (currently used
384 for information shared by sym_init and sym_read). It is
385 typically a pointer to malloc'd memory. The symbol reader's finish
386 function is responsible for freeing the memory thusly allocated. */
390 /* Hook for target-architecture-specific information. This must
391 point to memory allocated on one of the obstacks in this objfile,
392 so that it gets freed automatically when reading a new object
397 /* Per objfile data-pointers required by other GDB modules. */
398 /* FIXME: kettenis/20030711: This mechanism could replace
399 sym_stab_info, sym_private and obj_private entirely. */
404 /* Set of relocation offsets to apply to each section.
405 Currently on the psymbol_obstack (which makes no sense, but I'm
406 not sure it's harming anything).
408 These offsets indicate that all symbols (including partial and
409 minimal symbols) which have been read have been relocated by this
410 much. Symbols which are yet to be read need to be relocated by
413 struct section_offsets
*section_offsets
;
416 /* Indexes in the section_offsets array. These are initialized by the
417 *_symfile_offsets() family of functions (som_symfile_offsets,
418 xcoff_symfile_offsets, default_symfile_offsets). In theory they
419 should correspond to the section indexes used by bfd for the
420 current objfile. The exception to this for the time being is the
426 int sect_index_rodata
;
428 /* These pointers are used to locate the section table, which
429 among other things, is used to map pc addresses into sections.
430 SECTIONS points to the first entry in the table, and
431 SECTIONS_END points to the first location past the last entry
432 in the table. Currently the table is stored on the
433 psymbol_obstack (which makes no sense, but I'm not sure it's
434 harming anything). */
437 *sections
, *sections_end
;
439 /* two auxiliary fields, used to hold the fp of separate symbol files */
442 /* Imported symbols */
443 ImportEntry
*import_list
;
444 int import_list_size
;
446 /* Exported symbols */
447 ExportEntry
*export_list
;
448 int export_list_size
;
450 /* Link to objfile that contains the debug symbols for this one.
451 One is loaded if this file has an debug link to an existing
452 debug file with the right checksum */
453 struct objfile
*separate_debug_objfile
;
455 /* If this is a separate debug object, this is used as a link to the
456 actual executable objfile. */
457 struct objfile
*separate_debug_objfile_backlink
;
459 /* Place to stash various statistics about this objfile */
462 /* A symtab that the C++ code uses to stash special symbols
463 associated to namespaces. */
465 /* FIXME/carlton-2003-06-27: Delete this in a few years once
466 "possible namespace symbols" go away. */
467 struct symtab
*cp_namespace_symtab
;
470 /* Defines for the objfile flag word. */
472 /* Gdb can arrange to allocate storage for all objects related to a
473 particular objfile in a designated section of its address space,
474 managed at a low level by mmap() and using a special version of
475 malloc that handles malloc/free/realloc on top of the mmap() interface.
476 This allows the "internal gdb state" for a particular objfile to be
477 dumped to a gdb state file and subsequently reloaded at a later time. */
479 #define OBJF_MAPPED (1 << 0) /* Objfile data is mmap'd */
481 /* When using mapped/remapped predigested gdb symbol information, we need
482 a flag that indicates that we have previously done an initial symbol
483 table read from this particular objfile. We can't just look for the
484 absence of any of the three symbol tables (msymbols, psymtab, symtab)
485 because if the file has no symbols for example, none of these will
488 #define OBJF_SYMS (1 << 1) /* Have tried to read symbols */
490 /* When an object file has its functions reordered (currently Irix-5.2
491 shared libraries exhibit this behaviour), we will need an expensive
492 algorithm to locate a partial symtab or symtab via an address.
493 To avoid this penalty for normal object files, we use this flag,
494 whose setting is determined upon symbol table read in. */
496 #define OBJF_REORDERED (1 << 2) /* Functions are reordered */
498 /* Distinguish between an objfile for a shared library and a "vanilla"
499 objfile. (If not set, the objfile may still actually be a solib.
500 This can happen if the user created the objfile by using the
501 add-symbol-file command. GDB doesn't in that situation actually
502 check whether the file is a solib. Rather, the target's
503 implementation of the solib interface is responsible for setting
504 this flag when noticing solibs used by an inferior.) */
506 #define OBJF_SHARED (1 << 3) /* From a shared library */
508 /* User requested that this objfile be read in it's entirety. */
510 #define OBJF_READNOW (1 << 4) /* Immediate full read */
512 /* This objfile was created because the user explicitly caused it
513 (e.g., used the add-symbol-file command). This bit offers a way
514 for run_command to remove old objfile entries which are no longer
515 valid (i.e., are associated with an old inferior), but to preserve
516 ones that the user explicitly loaded via the add-symbol-file
519 #define OBJF_USERLOADED (1 << 5) /* User loaded */
521 /* The object file that the main symbol table was loaded from (e.g. the
522 argument to the "symbol-file" or "file" command). */
524 extern struct objfile
*symfile_objfile
;
526 /* The object file that contains the runtime common minimal symbols
527 for SunOS4. Note that this objfile has no associated BFD. */
529 extern struct objfile
*rt_common_objfile
;
531 /* When we need to allocate a new type, we need to know which type_obstack
532 to allocate the type on, since there is one for each objfile. The places
533 where types are allocated are deeply buried in function call hierarchies
534 which know nothing about objfiles, so rather than trying to pass a
535 particular objfile down to them, we just do an end run around them and
536 set current_objfile to be whatever objfile we expect to be using at the
537 time types are being allocated. For instance, when we start reading
538 symbols for a particular objfile, we set current_objfile to point to that
539 objfile, and when we are done, we set it back to NULL, to ensure that we
540 never put a type someplace other than where we are expecting to put it.
541 FIXME: Maybe we should review the entire type handling system and
542 see if there is a better way to avoid this problem. */
544 extern struct objfile
*current_objfile
;
546 /* All known objfiles are kept in a linked list. This points to the
547 root of this list. */
549 extern struct objfile
*object_files
;
551 /* Declarations for functions defined in objfiles.c */
553 extern struct objfile
*allocate_objfile (bfd
*, int);
555 extern int build_objfile_section_table (struct objfile
*);
557 extern void terminate_minimal_symbol_table (struct objfile
*objfile
);
559 extern void put_objfile_before (struct objfile
*, struct objfile
*);
561 extern void objfile_to_front (struct objfile
*);
563 extern void unlink_objfile (struct objfile
*);
565 extern void free_objfile (struct objfile
*);
567 extern struct cleanup
*make_cleanup_free_objfile (struct objfile
*);
569 extern void free_all_objfiles (void);
571 extern void objfile_relocate (struct objfile
*, struct section_offsets
*);
573 extern int have_partial_symbols (void);
575 extern int have_full_symbols (void);
577 /* This operation deletes all objfile entries that represent solibs that
578 weren't explicitly loaded by the user, via e.g., the add-symbol-file
581 extern void objfile_purge_solibs (void);
583 /* Functions for dealing with the minimal symbol table, really a misc
584 address<->symbol mapping for things we don't have debug symbols for. */
586 extern int have_minimal_symbols (void);
588 extern struct obj_section
*find_pc_section (CORE_ADDR pc
);
590 extern struct obj_section
*find_pc_sect_section (CORE_ADDR pc
,
593 extern int in_plt_section (CORE_ADDR
, char *);
595 extern int is_in_import_list (char *, struct objfile
*);
597 /* Keep a registry of per-objfile data-pointers required by other GDB
600 extern const struct objfile_data
*register_objfile_data (void);
601 extern void set_objfile_data (struct objfile
*objfile
,
602 const struct objfile_data
*data
, void *value
);
603 extern void *objfile_data (struct objfile
*objfile
,
604 const struct objfile_data
*data
);
607 /* Traverse all object files. ALL_OBJFILES_SAFE works even if you delete
608 the objfile during the traversal. */
610 #define ALL_OBJFILES(obj) \
611 for ((obj) = object_files; (obj) != NULL; (obj) = (obj)->next)
613 #define ALL_OBJFILES_SAFE(obj,nxt) \
614 for ((obj) = object_files; \
615 (obj) != NULL? ((nxt)=(obj)->next,1) :0; \
618 /* Traverse all symtabs in one objfile. */
620 #define ALL_OBJFILE_SYMTABS(objfile, s) \
621 for ((s) = (objfile) -> symtabs; (s) != NULL; (s) = (s) -> next)
623 /* Traverse all psymtabs in one objfile. */
625 #define ALL_OBJFILE_PSYMTABS(objfile, p) \
626 for ((p) = (objfile) -> psymtabs; (p) != NULL; (p) = (p) -> next)
628 /* Traverse all minimal symbols in one objfile. */
630 #define ALL_OBJFILE_MSYMBOLS(objfile, m) \
631 for ((m) = (objfile) -> msymbols; DEPRECATED_SYMBOL_NAME(m) != NULL; (m)++)
633 /* Traverse all symtabs in all objfiles. */
635 #define ALL_SYMTABS(objfile, s) \
636 ALL_OBJFILES (objfile) \
637 ALL_OBJFILE_SYMTABS (objfile, s)
639 /* Traverse all psymtabs in all objfiles. */
641 #define ALL_PSYMTABS(objfile, p) \
642 ALL_OBJFILES (objfile) \
643 ALL_OBJFILE_PSYMTABS (objfile, p)
645 /* Traverse all minimal symbols in all objfiles. */
647 #define ALL_MSYMBOLS(objfile, m) \
648 ALL_OBJFILES (objfile) \
649 ALL_OBJFILE_MSYMBOLS (objfile, m)
651 #define ALL_OBJFILE_OSECTIONS(objfile, osect) \
652 for (osect = objfile->sections; osect < objfile->sections_end; osect++)
654 #define ALL_OBJSECTIONS(objfile, osect) \
655 ALL_OBJFILES (objfile) \
656 ALL_OBJFILE_OSECTIONS (objfile, osect)
658 #define SECT_OFF_DATA(objfile) \
659 ((objfile->sect_index_data == -1) \
660 ? (internal_error (__FILE__, __LINE__, "sect_index_data not initialized"), -1) \
661 : objfile->sect_index_data)
663 #define SECT_OFF_RODATA(objfile) \
664 ((objfile->sect_index_rodata == -1) \
665 ? (internal_error (__FILE__, __LINE__, "sect_index_rodata not initialized"), -1) \
666 : objfile->sect_index_rodata)
668 #define SECT_OFF_TEXT(objfile) \
669 ((objfile->sect_index_text == -1) \
670 ? (internal_error (__FILE__, __LINE__, "sect_index_text not initialized"), -1) \
671 : objfile->sect_index_text)
673 /* Sometimes the .bss section is missing from the objfile, so we don't
674 want to die here. Let the users of SECT_OFF_BSS deal with an
675 uninitialized section index. */
676 #define SECT_OFF_BSS(objfile) (objfile)->sect_index_bss
678 #endif /* !defined (OBJFILES_H) */