1 /* Definitions for symbol file management in GDB.
2 Copyright (C) 1992, 1993, 1994, 1995, 1999 Free Software Foundation, Inc.
4 This file is part of GDB.
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, Inc., 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
21 #if !defined (OBJFILES_H)
24 /* This structure maintains information on a per-objfile basis about the
25 "entry point" of the objfile, and the scope within which the entry point
26 exists. It is possible that gdb will see more than one objfile that is
27 executable, each with its own entry point.
29 For example, for dynamically linked executables in SVR4, the dynamic linker
30 code is contained within the shared C library, which is actually executable
31 and is run by the kernel first when an exec is done of a user executable
32 that is dynamically linked. The dynamic linker within the shared C library
33 then maps in the various program segments in the user executable and jumps
34 to the user executable's recorded entry point, as if the call had been made
35 directly by the kernel.
37 The traditional gdb method of using this info is to use the recorded entry
38 point to set the variables entry_file_lowpc and entry_file_highpc from
39 the debugging information, where these values are the starting address
40 (inclusive) and ending address (exclusive) of the instruction space in the
41 executable which correspond to the "startup file", I.E. crt0.o in most
42 cases. This file is assumed to be a startup file and frames with pc's
43 inside it are treated as nonexistent. Setting these variables is necessary
44 so that backtraces do not fly off the bottom of the stack.
46 Gdb also supports an alternate method to avoid running off the bottom
49 There are two frames that are "special", the frame for the function
50 containing the process entry point, since it has no predecessor frame,
51 and the frame for the function containing the user code entry point
52 (the main() function), since all the predecessor frames are for the
53 process startup code. Since we have no guarantee that the linked
54 in startup modules have any debugging information that gdb can use,
55 we need to avoid following frame pointers back into frames that might
56 have been built in the startup code, as we might get hopelessly
57 confused. However, we almost always have debugging information
60 These variables are used to save the range of PC values which are valid
61 within the main() function and within the function containing the process
62 entry point. If we always consider the frame for main() as the outermost
63 frame when debugging user code, and the frame for the process entry
64 point function as the outermost frame when debugging startup code, then
65 all we have to do is have FRAME_CHAIN_VALID return false whenever a
66 frame's current PC is within the range specified by these variables.
67 In essence, we set "ceilings" in the frame chain beyond which we will
68 not proceed when following the frame chain back up the stack.
70 A nice side effect is that we can still debug startup code without
71 running off the end of the frame chain, assuming that we have usable
72 debugging information in the startup modules, and if we choose to not
73 use the block at main, or can't find it for some reason, everything
74 still works as before. And if we have no startup code debugging
75 information but we do have usable information for main(), backtraces
76 from user code don't go wandering off into the startup code.
78 To use this method, define your FRAME_CHAIN_VALID macro like:
80 #define FRAME_CHAIN_VALID(chain, thisframe) \
82 && !(inside_main_func ((thisframe)->pc)) \
83 && !(inside_entry_func ((thisframe)->pc)))
85 and add initializations of the four scope controlling variables inside
86 the object file / debugging information processing modules. */
91 /* The value we should use for this objects entry point.
92 The illegal/unknown value needs to be something other than 0, ~0
93 for instance, which is much less likely than 0. */
95 CORE_ADDR entry_point;
97 #define INVALID_ENTRY_POINT (~0) /* ~0 will not be in any file, we hope. */
99 /* Start (inclusive) and end (exclusive) of function containing the
102 CORE_ADDR entry_func_lowpc;
103 CORE_ADDR entry_func_highpc;
105 /* Start (inclusive) and end (exclusive) of object file containing the
108 CORE_ADDR entry_file_lowpc;
109 CORE_ADDR entry_file_highpc;
111 /* Start (inclusive) and end (exclusive) of the user code main() function. */
113 CORE_ADDR main_func_lowpc;
114 CORE_ADDR main_func_highpc;
116 /* Use these values when any of the above ranges is invalid. */
118 /* We use these values because it guarantees that there is no number that is
119 both >= LOWPC && < HIGHPC. It is also highly unlikely that 3 is a valid
120 module or function start address (as opposed to 0). */
122 #define INVALID_ENTRY_LOWPC (3)
123 #define INVALID_ENTRY_HIGHPC (1)
127 /* Sections in an objfile.
129 It is strange that we have both this notion of "sections"
130 and the one used by section_offsets. Section as used
131 here, (currently at least) means a BFD section, and the sections
132 are set up from the BFD sections in allocate_objfile.
134 The sections in section_offsets have their meaning determined by
135 the symbol format, and they are set up by the sym_offsets function
136 for that symbol file format.
138 I'm not sure this could or should be changed, however. */
142 CORE_ADDR addr; /* lowest address in section */
143 CORE_ADDR endaddr; /* 1+highest address in section */
145 /* This field is being used for nefarious purposes by syms_from_objfile.
146 It is said to be redundant with section_offsets; it's not really being
147 used that way, however, it's some sort of hack I don't understand
148 and am not going to try to eliminate (yet, anyway). FIXME.
150 It was documented as "offset between (end)addr and actual memory
151 addresses", but that's not true; addr & endaddr are actual memory
155 sec_ptr the_bfd_section; /* BFD section pointer */
157 /* Objfile this section is part of. */
158 struct objfile *objfile;
160 /* True if this "overlay section" is mapped into an "overlay region". */
164 /* An import entry contains information about a symbol that
165 is used in this objfile but not defined in it, and so needs
166 to be imported from some other objfile */
167 /* Currently we just store the name; no attributes. 1997-08-05 */
168 typedef char *ImportEntry;
171 /* An export entry contains information about a symbol that
172 is defined in this objfile and available for use in other
176 char *name; /* name of exported symbol */
177 int address; /* offset subject to relocation */
178 /* Currently no other attributes 1997-08-05 */
183 /* The "objstats" structure provides a place for gdb to record some
184 interesting information about its internal state at runtime, on a
185 per objfile basis, such as information about the number of symbols
186 read, size of string table (if any), etc. */
190 int n_minsyms; /* Number of minimal symbols read */
191 int n_psyms; /* Number of partial symbols read */
192 int n_syms; /* Number of full symbols read */
193 int n_stabs; /* Number of ".stabs" read (if applicable) */
194 int n_types; /* Number of types */
195 int sz_strtab; /* Size of stringtable, (if applicable) */
198 #define OBJSTAT(objfile, expr) (objfile -> stats.expr)
199 #define OBJSTATS struct objstats stats
200 extern void print_objfile_statistics PARAMS ((void));
201 extern void print_symbol_bcache_statistics PARAMS ((void));
203 /* Number of entries in the minimal symbol hash table. */
204 #define MINIMAL_SYMBOL_HASH_SIZE 349
206 /* Master structure for keeping track of each file from which
207 gdb reads symbols. There are several ways these get allocated: 1.
208 The main symbol file, symfile_objfile, set by the symbol-file command,
209 2. Additional symbol files added by the add-symbol-file command,
210 3. Shared library objfiles, added by ADD_SOLIB, 4. symbol files
211 for modules that were loaded when GDB attached to a remote system
212 (see remote-vx.c). */
217 /* All struct objfile's are chained together by their next pointers.
218 The global variable "object_files" points to the first link in this
221 FIXME: There is a problem here if the objfile is reusable, and if
222 multiple users are to be supported. The problem is that the objfile
223 list is linked through a member of the objfile struct itself, which
224 is only valid for one gdb process. The list implementation needs to
225 be changed to something like:
227 struct list {struct list *next; struct objfile *objfile};
229 where the list structure is completely maintained separately within
232 struct objfile *next;
234 /* The object file's name. Malloc'd; free it if you free this struct. */
238 /* Some flag bits for this objfile. */
240 unsigned short flags;
242 /* Each objfile points to a linked list of symtabs derived from this file,
243 one symtab structure for each compilation unit (source file). Each link
244 in the symtab list contains a backpointer to this objfile. */
246 struct symtab *symtabs;
248 /* Each objfile points to a linked list of partial symtabs derived from
249 this file, one partial symtab structure for each compilation unit
252 struct partial_symtab *psymtabs;
254 /* List of freed partial symtabs, available for re-use */
256 struct partial_symtab *free_psymtabs;
258 /* The object file's BFD. Can be null if the objfile contains only
259 minimal symbols, e.g. the run time common symbols for SunOS4. */
263 /* The modification timestamp of the object file, as of the last time
264 we read its symbols. */
268 /* Obstacks to hold objects that should be freed when we load a new symbol
269 table from this object file. */
271 struct obstack psymbol_obstack; /* Partial symbols */
272 struct obstack symbol_obstack; /* Full symbols */
273 struct obstack type_obstack; /* Types */
275 /* A byte cache where we can stash arbitrary "chunks" of bytes that
278 struct bcache psymbol_cache; /* Byte cache for partial syms */
280 /* Vectors of all partial symbols read in from file. The actual data
281 is stored in the psymbol_obstack. */
283 struct psymbol_allocation_list global_psymbols;
284 struct psymbol_allocation_list static_psymbols;
286 /* Each file contains a pointer to an array of minimal symbols for all
287 global symbols that are defined within the file. The array is terminated
288 by a "null symbol", one that has a NULL pointer for the name and a zero
289 value for the address. This makes it easy to walk through the array
290 when passed a pointer to somewhere in the middle of it. There is also
291 a count of the number of symbols, which does not include the terminating
292 null symbol. The array itself, as well as all the data that it points
293 to, should be allocated on the symbol_obstack for this file. */
295 struct minimal_symbol *msymbols;
296 int minimal_symbol_count;
298 /* This is a hash table used to index the minimal symbols by name. */
300 struct minimal_symbol *msymbol_hash[MINIMAL_SYMBOL_HASH_SIZE];
302 /* This hash table is used to index the minimal symbols by their
305 struct minimal_symbol *msymbol_demangled_hash[MINIMAL_SYMBOL_HASH_SIZE];
307 /* For object file formats which don't specify fundamental types, gdb
308 can create such types. For now, it maintains a vector of pointers
309 to these internally created fundamental types on a per objfile basis,
310 however it really should ultimately keep them on a per-compilation-unit
311 basis, to account for linkage-units that consist of a number of
312 compilation units that may have different fundamental types, such as
313 linking C modules with ADA modules, or linking C modules that are
314 compiled with 32-bit ints with C modules that are compiled with 64-bit
315 ints (not inherently evil with a smarter linker). */
317 struct type **fundamental_types;
319 /* The mmalloc() malloc-descriptor for this objfile if we are using
320 the memory mapped malloc() package to manage storage for this objfile's
321 data. NULL if we are not. */
325 /* The file descriptor that was used to obtain the mmalloc descriptor
326 for this objfile. If we call mmalloc_detach with the malloc descriptor
327 we should then close this file descriptor. */
331 /* Structure which keeps track of functions that manipulate objfile's
332 of the same type as this objfile. I.E. the function to read partial
333 symbols for example. Note that this structure is in statically
334 allocated memory, and is shared by all objfiles that use the
335 object module reader of this type. */
339 /* The per-objfile information about the entry point, the scope (file/func)
340 containing the entry point, and the scope of the user's main() func. */
342 struct entry_info ei;
344 /* Information about stabs. Will be filled in with a dbx_symfile_info
345 struct by those readers that need it. */
347 struct dbx_symfile_info *sym_stab_info;
349 /* Hook for information for use by the symbol reader (currently used
350 for information shared by sym_init and sym_read). It is
351 typically a pointer to malloc'd memory. The symbol reader's finish
352 function is responsible for freeing the memory thusly allocated. */
356 /* Hook for target-architecture-specific information. This must
357 point to memory allocated on one of the obstacks in this objfile,
358 so that it gets freed automatically when reading a new object
363 /* Set of relocation offsets to apply to each section.
364 Currently on the psymbol_obstack (which makes no sense, but I'm
365 not sure it's harming anything).
367 These offsets indicate that all symbols (including partial and
368 minimal symbols) which have been read have been relocated by this
369 much. Symbols which are yet to be read need to be relocated by
372 struct section_offsets *section_offsets;
375 /* These pointers are used to locate the section table, which
376 among other things, is used to map pc addresses into sections.
377 SECTIONS points to the first entry in the table, and
378 SECTIONS_END points to the first location past the last entry
379 in the table. Currently the table is stored on the
380 psymbol_obstack (which makes no sense, but I'm not sure it's
381 harming anything). */
384 *sections, *sections_end;
386 /* two auxiliary fields, used to hold the fp of separate symbol files */
389 /* Imported symbols */
390 ImportEntry *import_list;
391 int import_list_size;
393 /* Exported symbols */
394 ExportEntry *export_list;
395 int export_list_size;
397 /* Place to stash various statistics about this objfile */
401 /* Defines for the objfile flag word. */
403 /* Gdb can arrange to allocate storage for all objects related to a
404 particular objfile in a designated section of its address space,
405 managed at a low level by mmap() and using a special version of
406 malloc that handles malloc/free/realloc on top of the mmap() interface.
407 This allows the "internal gdb state" for a particular objfile to be
408 dumped to a gdb state file and subsequently reloaded at a later time. */
410 #define OBJF_MAPPED (1 << 0) /* Objfile data is mmap'd */
412 /* When using mapped/remapped predigested gdb symbol information, we need
413 a flag that indicates that we have previously done an initial symbol
414 table read from this particular objfile. We can't just look for the
415 absence of any of the three symbol tables (msymbols, psymtab, symtab)
416 because if the file has no symbols for example, none of these will
419 #define OBJF_SYMS (1 << 1) /* Have tried to read symbols */
421 /* When an object file has its functions reordered (currently Irix-5.2
422 shared libraries exhibit this behaviour), we will need an expensive
423 algorithm to locate a partial symtab or symtab via an address.
424 To avoid this penalty for normal object files, we use this flag,
425 whose setting is determined upon symbol table read in. */
427 #define OBJF_REORDERED (1 << 2) /* Functions are reordered */
429 /* Distinguish between an objfile for a shared library and a "vanilla"
430 objfile. (If not set, the objfile may still actually be a solib.
431 This can happen if the user created the objfile by using the
432 add-symbol-file command. GDB doesn't in that situation actually
433 check whether the file is a solib. Rather, the target's
434 implementation of the solib interface is responsible for setting
435 this flag when noticing solibs used by an inferior.) */
437 #define OBJF_SHARED (1 << 3) /* From a shared library */
439 /* User requested that this objfile be read in it's entirety. */
441 #define OBJF_READNOW (1 << 4) /* Immediate full read */
443 /* This objfile was created because the user explicitly caused it
444 (e.g., used the add-symbol-file command). This bit offers a way
445 for run_command to remove old objfile entries which are no longer
446 valid (i.e., are associated with an old inferior), but to preserve
447 ones that the user explicitly loaded via the add-symbol-file
450 #define OBJF_USERLOADED (1 << 5) /* User loaded */
452 /* The object file that the main symbol table was loaded from (e.g. the
453 argument to the "symbol-file" or "file" command). */
455 extern struct objfile *symfile_objfile;
457 /* The object file that contains the runtime common minimal symbols
458 for SunOS4. Note that this objfile has no associated BFD. */
460 extern struct objfile *rt_common_objfile;
462 /* When we need to allocate a new type, we need to know which type_obstack
463 to allocate the type on, since there is one for each objfile. The places
464 where types are allocated are deeply buried in function call hierarchies
465 which know nothing about objfiles, so rather than trying to pass a
466 particular objfile down to them, we just do an end run around them and
467 set current_objfile to be whatever objfile we expect to be using at the
468 time types are being allocated. For instance, when we start reading
469 symbols for a particular objfile, we set current_objfile to point to that
470 objfile, and when we are done, we set it back to NULL, to ensure that we
471 never put a type someplace other than where we are expecting to put it.
472 FIXME: Maybe we should review the entire type handling system and
473 see if there is a better way to avoid this problem. */
475 extern struct objfile *current_objfile;
477 /* All known objfiles are kept in a linked list. This points to the
478 root of this list. */
480 extern struct objfile *object_files;
482 /* Declarations for functions defined in objfiles.c */
484 extern struct objfile *
485 allocate_objfile PARAMS ((bfd *, int));
488 build_objfile_section_table PARAMS ((struct objfile *));
490 extern void objfile_to_front PARAMS ((struct objfile *));
493 unlink_objfile PARAMS ((struct objfile *));
496 free_objfile PARAMS ((struct objfile *));
499 free_all_objfiles PARAMS ((void));
502 objfile_relocate PARAMS ((struct objfile *, struct section_offsets *));
505 have_partial_symbols PARAMS ((void));
508 have_full_symbols PARAMS ((void));
510 /* This operation deletes all objfile entries that represent solibs that
511 weren't explicitly loaded by the user, via e.g., the add-symbol-file
515 objfile_purge_solibs PARAMS ((void));
517 /* Functions for dealing with the minimal symbol table, really a misc
518 address<->symbol mapping for things we don't have debug symbols for. */
521 have_minimal_symbols PARAMS ((void));
523 extern struct obj_section *
524 find_pc_section PARAMS ((CORE_ADDR pc));
526 extern struct obj_section *
527 find_pc_sect_section PARAMS ((CORE_ADDR pc, asection * section));
530 in_plt_section PARAMS ((CORE_ADDR, char *));
533 is_in_import_list PARAMS ((char *, struct objfile *));
535 /* Traverse all object files. ALL_OBJFILES_SAFE works even if you delete
536 the objfile during the traversal. */
538 #define ALL_OBJFILES(obj) \
539 for ((obj) = object_files; (obj) != NULL; (obj) = (obj)->next)
541 #define ALL_OBJFILES_SAFE(obj,nxt) \
542 for ((obj) = object_files; \
543 (obj) != NULL? ((nxt)=(obj)->next,1) :0; \
546 /* Traverse all symtabs in one objfile. */
548 #define ALL_OBJFILE_SYMTABS(objfile, s) \
549 for ((s) = (objfile) -> symtabs; (s) != NULL; (s) = (s) -> next)
551 /* Traverse all psymtabs in one objfile. */
553 #define ALL_OBJFILE_PSYMTABS(objfile, p) \
554 for ((p) = (objfile) -> psymtabs; (p) != NULL; (p) = (p) -> next)
556 /* Traverse all minimal symbols in one objfile. */
558 #define ALL_OBJFILE_MSYMBOLS(objfile, m) \
559 for ((m) = (objfile) -> msymbols; SYMBOL_NAME(m) != NULL; (m)++)
561 /* Traverse all symtabs in all objfiles. */
563 #define ALL_SYMTABS(objfile, s) \
564 ALL_OBJFILES (objfile) \
565 ALL_OBJFILE_SYMTABS (objfile, s)
567 /* Traverse all psymtabs in all objfiles. */
569 #define ALL_PSYMTABS(objfile, p) \
570 ALL_OBJFILES (objfile) \
571 ALL_OBJFILE_PSYMTABS (objfile, p)
573 /* Traverse all minimal symbols in all objfiles. */
575 #define ALL_MSYMBOLS(objfile, m) \
576 ALL_OBJFILES (objfile) \
577 if ((objfile)->msymbols) \
578 ALL_OBJFILE_MSYMBOLS (objfile, m)
580 #define ALL_OBJFILE_OSECTIONS(objfile, osect) \
581 for (osect = objfile->sections; osect < objfile->sections_end; osect++)
583 #define ALL_OBJSECTIONS(objfile, osect) \
584 ALL_OBJFILES (objfile) \
585 ALL_OBJFILE_OSECTIONS (objfile, osect)
587 #endif /* !defined (OBJFILES_H) */