xref: /netbsd-src/external/gpl3/gdb.old/dist/gdb/minsyms.c (revision c38e7cc395b1472a774ff828e46123de44c628e9)
1 /* GDB routines for manipulating the minimal symbol tables.
2    Copyright (C) 1992-2016 Free Software Foundation, Inc.
3    Contributed by Cygnus Support, using pieces from other GDB modules.
4 
5    This file is part of GDB.
6 
7    This program is free software; you can redistribute it and/or modify
8    it under the terms of the GNU General Public License as published by
9    the Free Software Foundation; either version 3 of the License, or
10    (at your option) any later version.
11 
12    This program is distributed in the hope that it will be useful,
13    but WITHOUT ANY WARRANTY; without even the implied warranty of
14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15    GNU General Public License for more details.
16 
17    You should have received a copy of the GNU General Public License
18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
19 
20 
21 /* This file contains support routines for creating, manipulating, and
22    destroying minimal symbol tables.
23 
24    Minimal symbol tables are used to hold some very basic information about
25    all defined global symbols (text, data, bss, abs, etc).  The only two
26    required pieces of information are the symbol's name and the address
27    associated with that symbol.
28 
29    In many cases, even if a file was compiled with no special options for
30    debugging at all, as long as was not stripped it will contain sufficient
31    information to build useful minimal symbol tables using this structure.
32 
33    Even when a file contains enough debugging information to build a full
34    symbol table, these minimal symbols are still useful for quickly mapping
35    between names and addresses, and vice versa.  They are also sometimes used
36    to figure out what full symbol table entries need to be read in.  */
37 
38 
39 #include "defs.h"
40 #include <ctype.h>
41 #include "symtab.h"
42 #include "bfd.h"
43 #include "filenames.h"
44 #include "symfile.h"
45 #include "objfiles.h"
46 #include "demangle.h"
47 #include "value.h"
48 #include "cp-abi.h"
49 #include "target.h"
50 #include "cp-support.h"
51 #include "language.h"
52 #include "cli/cli-utils.h"
53 #include "symbol.h"
54 
55 /* Accumulate the minimal symbols for each objfile in bunches of BUNCH_SIZE.
56    At the end, copy them all into one newly allocated location on an objfile's
57    per-BFD storage obstack.  */
58 
59 #define BUNCH_SIZE 127
60 
61 struct msym_bunch
62   {
63     struct msym_bunch *next;
64     struct minimal_symbol contents[BUNCH_SIZE];
65   };
66 
67 /* Bunch currently being filled up.
68    The next field points to chain of filled bunches.  */
69 
70 static struct msym_bunch *msym_bunch;
71 
72 /* Number of slots filled in current bunch.  */
73 
74 static int msym_bunch_index;
75 
76 /* Total number of minimal symbols recorded so far for the objfile.  */
77 
78 static int msym_count;
79 
80 /* See minsyms.h.  */
81 
82 unsigned int
83 msymbol_hash_iw (const char *string)
84 {
85   unsigned int hash = 0;
86 
87   while (*string && *string != '(')
88     {
89       string = skip_spaces_const (string);
90       if (*string && *string != '(')
91 	{
92 	  hash = SYMBOL_HASH_NEXT (hash, *string);
93 	  ++string;
94 	}
95     }
96   return hash;
97 }
98 
99 /* See minsyms.h.  */
100 
101 unsigned int
102 msymbol_hash (const char *string)
103 {
104   unsigned int hash = 0;
105 
106   for (; *string; ++string)
107     hash = SYMBOL_HASH_NEXT (hash, *string);
108   return hash;
109 }
110 
111 /* Add the minimal symbol SYM to an objfile's minsym hash table, TABLE.  */
112 static void
113 add_minsym_to_hash_table (struct minimal_symbol *sym,
114 			  struct minimal_symbol **table)
115 {
116   if (sym->hash_next == NULL)
117     {
118       unsigned int hash
119 	= msymbol_hash (MSYMBOL_LINKAGE_NAME (sym)) % MINIMAL_SYMBOL_HASH_SIZE;
120 
121       sym->hash_next = table[hash];
122       table[hash] = sym;
123     }
124 }
125 
126 /* Add the minimal symbol SYM to an objfile's minsym demangled hash table,
127    TABLE.  */
128 static void
129 add_minsym_to_demangled_hash_table (struct minimal_symbol *sym,
130                                   struct minimal_symbol **table)
131 {
132   if (sym->demangled_hash_next == NULL)
133     {
134       unsigned int hash = msymbol_hash_iw (MSYMBOL_SEARCH_NAME (sym))
135 	% MINIMAL_SYMBOL_HASH_SIZE;
136 
137       sym->demangled_hash_next = table[hash];
138       table[hash] = sym;
139     }
140 }
141 
142 /* Look through all the current minimal symbol tables and find the
143    first minimal symbol that matches NAME.  If OBJF is non-NULL, limit
144    the search to that objfile.  If SFILE is non-NULL, the only file-scope
145    symbols considered will be from that source file (global symbols are
146    still preferred).  Returns a pointer to the minimal symbol that
147    matches, or NULL if no match is found.
148 
149    Note:  One instance where there may be duplicate minimal symbols with
150    the same name is when the symbol tables for a shared library and the
151    symbol tables for an executable contain global symbols with the same
152    names (the dynamic linker deals with the duplication).
153 
154    It's also possible to have minimal symbols with different mangled
155    names, but identical demangled names.  For example, the GNU C++ v3
156    ABI requires the generation of two (or perhaps three) copies of
157    constructor functions --- "in-charge", "not-in-charge", and
158    "allocate" copies; destructors may be duplicated as well.
159    Obviously, there must be distinct mangled names for each of these,
160    but the demangled names are all the same: S::S or S::~S.  */
161 
162 struct bound_minimal_symbol
163 lookup_minimal_symbol (const char *name, const char *sfile,
164 		       struct objfile *objf)
165 {
166   struct objfile *objfile;
167   struct bound_minimal_symbol found_symbol = { NULL, NULL };
168   struct bound_minimal_symbol found_file_symbol = { NULL, NULL };
169   struct bound_minimal_symbol trampoline_symbol = { NULL, NULL };
170 
171   unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
172   unsigned int dem_hash = msymbol_hash_iw (name) % MINIMAL_SYMBOL_HASH_SIZE;
173 
174   int needtofreename = 0;
175   const char *modified_name;
176 
177   if (sfile != NULL)
178     sfile = lbasename (sfile);
179 
180   /* For C++, canonicalize the input name.  */
181   modified_name = name;
182   if (current_language->la_language == language_cplus)
183     {
184       char *cname = cp_canonicalize_string (name);
185 
186       if (cname)
187 	{
188 	  modified_name = cname;
189 	  needtofreename = 1;
190 	}
191     }
192 
193   for (objfile = object_files;
194        objfile != NULL && found_symbol.minsym == NULL;
195        objfile = objfile->next)
196     {
197       struct minimal_symbol *msymbol;
198 
199       if (objf == NULL || objf == objfile
200 	  || objf == objfile->separate_debug_objfile_backlink)
201 	{
202 	  /* Do two passes: the first over the ordinary hash table,
203 	     and the second over the demangled hash table.  */
204         int pass;
205 
206 	if (symbol_lookup_debug)
207 	  {
208 	    fprintf_unfiltered (gdb_stdlog,
209 				"lookup_minimal_symbol (%s, %s, %s)\n",
210 				name, sfile != NULL ? sfile : "NULL",
211 				objfile_debug_name (objfile));
212 	  }
213 
214         for (pass = 1; pass <= 2 && found_symbol.minsym == NULL; pass++)
215 	    {
216             /* Select hash list according to pass.  */
217             if (pass == 1)
218               msymbol = objfile->per_bfd->msymbol_hash[hash];
219             else
220               msymbol = objfile->per_bfd->msymbol_demangled_hash[dem_hash];
221 
222             while (msymbol != NULL && found_symbol.minsym == NULL)
223 		{
224 		  int match;
225 
226 		  if (pass == 1)
227 		    {
228 		      int (*cmp) (const char *, const char *);
229 
230 		      cmp = (case_sensitivity == case_sensitive_on
231 		             ? strcmp : strcasecmp);
232 		      match = cmp (MSYMBOL_LINKAGE_NAME (msymbol),
233 				   modified_name) == 0;
234 		    }
235 		  else
236 		    {
237 		      /* The function respects CASE_SENSITIVITY.  */
238 		      match = MSYMBOL_MATCHES_SEARCH_NAME (msymbol,
239 							  modified_name);
240 		    }
241 
242 		  if (match)
243 		    {
244                     switch (MSYMBOL_TYPE (msymbol))
245                       {
246                       case mst_file_text:
247                       case mst_file_data:
248                       case mst_file_bss:
249                         if (sfile == NULL
250 			    || filename_cmp (msymbol->filename, sfile) == 0)
251 			  {
252 			    found_file_symbol.minsym = msymbol;
253 			    found_file_symbol.objfile = objfile;
254 			  }
255                         break;
256 
257                       case mst_solib_trampoline:
258 
259                         /* If a trampoline symbol is found, we prefer to
260                            keep looking for the *real* symbol.  If the
261                            actual symbol is not found, then we'll use the
262                            trampoline entry.  */
263                         if (trampoline_symbol.minsym == NULL)
264 			  {
265 			    trampoline_symbol.minsym = msymbol;
266 			    trampoline_symbol.objfile = objfile;
267 			  }
268                         break;
269 
270                       case mst_unknown:
271                       default:
272                         found_symbol.minsym = msymbol;
273 			found_symbol.objfile = objfile;
274                         break;
275                       }
276 		    }
277 
278                 /* Find the next symbol on the hash chain.  */
279                 if (pass == 1)
280                   msymbol = msymbol->hash_next;
281                 else
282                   msymbol = msymbol->demangled_hash_next;
283 		}
284 	    }
285 	}
286     }
287 
288   if (needtofreename)
289     xfree ((void *) modified_name);
290 
291   /* External symbols are best.  */
292   if (found_symbol.minsym != NULL)
293     {
294       if (symbol_lookup_debug)
295 	{
296 	  fprintf_unfiltered (gdb_stdlog,
297 			      "lookup_minimal_symbol (...) = %s"
298 			      " (external)\n",
299 			      host_address_to_string (found_symbol.minsym));
300 	}
301       return found_symbol;
302     }
303 
304   /* File-local symbols are next best.  */
305   if (found_file_symbol.minsym != NULL)
306     {
307       if (symbol_lookup_debug)
308 	{
309 	  fprintf_unfiltered (gdb_stdlog,
310 			      "lookup_minimal_symbol (...) = %s"
311 			      " (file-local)\n",
312 			      host_address_to_string
313 			        (found_file_symbol.minsym));
314 	}
315       return found_file_symbol;
316     }
317 
318   /* Symbols for shared library trampolines are next best.  */
319   if (symbol_lookup_debug)
320     {
321       fprintf_unfiltered (gdb_stdlog,
322 			  "lookup_minimal_symbol (...) = %s%s\n",
323 			  trampoline_symbol.minsym != NULL
324 			  ? host_address_to_string (trampoline_symbol.minsym)
325 			  : "NULL",
326 			  trampoline_symbol.minsym != NULL
327 			  ? " (trampoline)" : "");
328     }
329   return trampoline_symbol;
330 }
331 
332 /* See minsyms.h.  */
333 
334 struct bound_minimal_symbol
335 lookup_bound_minimal_symbol (const char *name)
336 {
337   return lookup_minimal_symbol (name, NULL, NULL);
338 }
339 
340 /* See common/symbol.h.  */
341 
342 int
343 find_minimal_symbol_address (const char *name, CORE_ADDR *addr,
344 			     struct objfile *objfile)
345 {
346   struct bound_minimal_symbol sym
347     = lookup_minimal_symbol (name, NULL, objfile);
348 
349   if (sym.minsym != NULL)
350     *addr = BMSYMBOL_VALUE_ADDRESS (sym);
351 
352   return sym.minsym == NULL;
353 }
354 
355 /* See minsyms.h.  */
356 
357 void
358 iterate_over_minimal_symbols (struct objfile *objf, const char *name,
359 			      void (*callback) (struct minimal_symbol *,
360 						void *),
361 			      void *user_data)
362 {
363   unsigned int hash;
364   struct minimal_symbol *iter;
365   int (*cmp) (const char *, const char *);
366 
367   /* The first pass is over the ordinary hash table.  */
368   hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
369   iter = objf->per_bfd->msymbol_hash[hash];
370   cmp = (case_sensitivity == case_sensitive_on ? strcmp : strcasecmp);
371   while (iter)
372     {
373       if (cmp (MSYMBOL_LINKAGE_NAME (iter), name) == 0)
374 	(*callback) (iter, user_data);
375       iter = iter->hash_next;
376     }
377 
378   /* The second pass is over the demangled table.  */
379   hash = msymbol_hash_iw (name) % MINIMAL_SYMBOL_HASH_SIZE;
380   iter = objf->per_bfd->msymbol_demangled_hash[hash];
381   while (iter)
382     {
383       if (MSYMBOL_MATCHES_SEARCH_NAME (iter, name))
384 	(*callback) (iter, user_data);
385       iter = iter->demangled_hash_next;
386     }
387 }
388 
389 /* See minsyms.h.  */
390 
391 struct bound_minimal_symbol
392 lookup_minimal_symbol_text (const char *name, struct objfile *objf)
393 {
394   struct objfile *objfile;
395   struct minimal_symbol *msymbol;
396   struct bound_minimal_symbol found_symbol = { NULL, NULL };
397   struct bound_minimal_symbol found_file_symbol = { NULL, NULL };
398 
399   unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
400 
401   for (objfile = object_files;
402        objfile != NULL && found_symbol.minsym == NULL;
403        objfile = objfile->next)
404     {
405       if (objf == NULL || objf == objfile
406 	  || objf == objfile->separate_debug_objfile_backlink)
407 	{
408 	  for (msymbol = objfile->per_bfd->msymbol_hash[hash];
409 	       msymbol != NULL && found_symbol.minsym == NULL;
410 	       msymbol = msymbol->hash_next)
411 	    {
412 	      if (strcmp (MSYMBOL_LINKAGE_NAME (msymbol), name) == 0 &&
413 		  (MSYMBOL_TYPE (msymbol) == mst_text
414 		   || MSYMBOL_TYPE (msymbol) == mst_text_gnu_ifunc
415 		   || MSYMBOL_TYPE (msymbol) == mst_file_text))
416 		{
417 		  switch (MSYMBOL_TYPE (msymbol))
418 		    {
419 		    case mst_file_text:
420 		      found_file_symbol.minsym = msymbol;
421 		      found_file_symbol.objfile = objfile;
422 		      break;
423 		    default:
424 		      found_symbol.minsym = msymbol;
425 		      found_symbol.objfile = objfile;
426 		      break;
427 		    }
428 		}
429 	    }
430 	}
431     }
432   /* External symbols are best.  */
433   if (found_symbol.minsym)
434     return found_symbol;
435 
436   /* File-local symbols are next best.  */
437   return found_file_symbol;
438 }
439 
440 /* See minsyms.h.  */
441 
442 struct minimal_symbol *
443 lookup_minimal_symbol_by_pc_name (CORE_ADDR pc, const char *name,
444 				  struct objfile *objf)
445 {
446   struct objfile *objfile;
447   struct minimal_symbol *msymbol;
448 
449   unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
450 
451   for (objfile = object_files;
452        objfile != NULL;
453        objfile = objfile->next)
454     {
455       if (objf == NULL || objf == objfile
456 	  || objf == objfile->separate_debug_objfile_backlink)
457 	{
458 	  for (msymbol = objfile->per_bfd->msymbol_hash[hash];
459 	       msymbol != NULL;
460 	       msymbol = msymbol->hash_next)
461 	    {
462 	      if (MSYMBOL_VALUE_ADDRESS (objfile, msymbol) == pc
463 		  && strcmp (MSYMBOL_LINKAGE_NAME (msymbol), name) == 0)
464 		return msymbol;
465 	    }
466 	}
467     }
468 
469   return NULL;
470 }
471 
472 /* See minsyms.h.  */
473 
474 struct bound_minimal_symbol
475 lookup_minimal_symbol_solib_trampoline (const char *name,
476 					struct objfile *objf)
477 {
478   struct objfile *objfile;
479   struct minimal_symbol *msymbol;
480   struct bound_minimal_symbol found_symbol = { NULL, NULL };
481 
482   unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
483 
484   for (objfile = object_files;
485        objfile != NULL;
486        objfile = objfile->next)
487     {
488       if (objf == NULL || objf == objfile
489 	  || objf == objfile->separate_debug_objfile_backlink)
490 	{
491 	  for (msymbol = objfile->per_bfd->msymbol_hash[hash];
492 	       msymbol != NULL;
493 	       msymbol = msymbol->hash_next)
494 	    {
495 	      if (strcmp (MSYMBOL_LINKAGE_NAME (msymbol), name) == 0 &&
496 		  MSYMBOL_TYPE (msymbol) == mst_solib_trampoline)
497 		{
498 		  found_symbol.objfile = objfile;
499 		  found_symbol.minsym = msymbol;
500 		  return found_symbol;
501 		}
502 	    }
503 	}
504     }
505 
506   return found_symbol;
507 }
508 
509 /* A helper function that makes *PC section-relative.  This searches
510    the sections of OBJFILE and if *PC is in a section, it subtracts
511    the section offset and returns true.  Otherwise it returns
512    false.  */
513 
514 static int
515 frob_address (struct objfile *objfile, CORE_ADDR *pc)
516 {
517   struct obj_section *iter;
518 
519   ALL_OBJFILE_OSECTIONS (objfile, iter)
520     {
521       if (*pc >= obj_section_addr (iter) && *pc < obj_section_endaddr (iter))
522 	{
523 	  *pc -= obj_section_offset (iter);
524 	  return 1;
525 	}
526     }
527 
528   return 0;
529 }
530 
531 /* Search through the minimal symbol table for each objfile and find
532    the symbol whose address is the largest address that is still less
533    than or equal to PC, and matches SECTION (which is not NULL).
534    Returns a pointer to the minimal symbol if such a symbol is found,
535    or NULL if PC is not in a suitable range.
536    Note that we need to look through ALL the minimal symbol tables
537    before deciding on the symbol that comes closest to the specified PC.
538    This is because objfiles can overlap, for example objfile A has .text
539    at 0x100 and .data at 0x40000 and objfile B has .text at 0x234 and
540    .data at 0x40048.
541 
542    If WANT_TRAMPOLINE is set, prefer mst_solib_trampoline symbols when
543    there are text and trampoline symbols at the same address.
544    Otherwise prefer mst_text symbols.  */
545 
546 static struct bound_minimal_symbol
547 lookup_minimal_symbol_by_pc_section_1 (CORE_ADDR pc_in,
548 				       struct obj_section *section,
549 				       int want_trampoline)
550 {
551   int lo;
552   int hi;
553   int newobj;
554   struct objfile *objfile;
555   struct minimal_symbol *msymbol;
556   struct minimal_symbol *best_symbol = NULL;
557   struct objfile *best_objfile = NULL;
558   struct bound_minimal_symbol result;
559   enum minimal_symbol_type want_type, other_type;
560 
561   want_type = want_trampoline ? mst_solib_trampoline : mst_text;
562   other_type = want_trampoline ? mst_text : mst_solib_trampoline;
563 
564   /* We can not require the symbol found to be in section, because
565      e.g. IRIX 6.5 mdebug relies on this code returning an absolute
566      symbol - but find_pc_section won't return an absolute section and
567      hence the code below would skip over absolute symbols.  We can
568      still take advantage of the call to find_pc_section, though - the
569      object file still must match.  In case we have separate debug
570      files, search both the file and its separate debug file.  There's
571      no telling which one will have the minimal symbols.  */
572 
573   gdb_assert (section != NULL);
574 
575   for (objfile = section->objfile;
576        objfile != NULL;
577        objfile = objfile_separate_debug_iterate (section->objfile, objfile))
578     {
579       CORE_ADDR pc = pc_in;
580 
581       /* If this objfile has a minimal symbol table, go search it using
582          a binary search.  Note that a minimal symbol table always consists
583          of at least two symbols, a "real" symbol and the terminating
584          "null symbol".  If there are no real symbols, then there is no
585          minimal symbol table at all.  */
586 
587       if (objfile->per_bfd->minimal_symbol_count > 0)
588 	{
589 	  int best_zero_sized = -1;
590 
591           msymbol = objfile->per_bfd->msymbols;
592 	  lo = 0;
593 	  hi = objfile->per_bfd->minimal_symbol_count - 1;
594 
595 	  /* This code assumes that the minimal symbols are sorted by
596 	     ascending address values.  If the pc value is greater than or
597 	     equal to the first symbol's address, then some symbol in this
598 	     minimal symbol table is a suitable candidate for being the
599 	     "best" symbol.  This includes the last real symbol, for cases
600 	     where the pc value is larger than any address in this vector.
601 
602 	     By iterating until the address associated with the current
603 	     hi index (the endpoint of the test interval) is less than
604 	     or equal to the desired pc value, we accomplish two things:
605 	     (1) the case where the pc value is larger than any minimal
606 	     symbol address is trivially solved, (2) the address associated
607 	     with the hi index is always the one we want when the interation
608 	     terminates.  In essence, we are iterating the test interval
609 	     down until the pc value is pushed out of it from the high end.
610 
611 	     Warning: this code is trickier than it would appear at first.  */
612 
613 	  if (frob_address (objfile, &pc)
614 	      && pc >= MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[lo]))
615 	    {
616 	      while (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi]) > pc)
617 		{
618 		  /* pc is still strictly less than highest address.  */
619 		  /* Note "new" will always be >= lo.  */
620 		  newobj = (lo + hi) / 2;
621 		  if ((MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[newobj]) >= pc)
622 		      || (lo == newobj))
623 		    {
624 		      hi = newobj;
625 		    }
626 		  else
627 		    {
628 		      lo = newobj;
629 		    }
630 		}
631 
632 	      /* If we have multiple symbols at the same address, we want
633 	         hi to point to the last one.  That way we can find the
634 	         right symbol if it has an index greater than hi.  */
635 	      while (hi < objfile->per_bfd->minimal_symbol_count - 1
636 		     && (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])
637 			 == MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi + 1])))
638 		hi++;
639 
640 	      /* Skip various undesirable symbols.  */
641 	      while (hi >= 0)
642 		{
643 		  /* Skip any absolute symbols.  This is apparently
644 		     what adb and dbx do, and is needed for the CM-5.
645 		     There are two known possible problems: (1) on
646 		     ELF, apparently end, edata, etc. are absolute.
647 		     Not sure ignoring them here is a big deal, but if
648 		     we want to use them, the fix would go in
649 		     elfread.c.  (2) I think shared library entry
650 		     points on the NeXT are absolute.  If we want
651 		     special handling for this it probably should be
652 		     triggered by a special mst_abs_or_lib or some
653 		     such.  */
654 
655 		  if (MSYMBOL_TYPE (&msymbol[hi]) == mst_abs)
656 		    {
657 		      hi--;
658 		      continue;
659 		    }
660 
661 		  /* If SECTION was specified, skip any symbol from
662 		     wrong section.  */
663 		  if (section
664 		      /* Some types of debug info, such as COFF,
665 			 don't fill the bfd_section member, so don't
666 			 throw away symbols on those platforms.  */
667 		      && MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi]) != NULL
668 		      && (!matching_obj_sections
669 			  (MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi]),
670 			   section)))
671 		    {
672 		      hi--;
673 		      continue;
674 		    }
675 
676 		  /* If we are looking for a trampoline and this is a
677 		     text symbol, or the other way around, check the
678 		     preceding symbol too.  If they are otherwise
679 		     identical prefer that one.  */
680 		  if (hi > 0
681 		      && MSYMBOL_TYPE (&msymbol[hi]) == other_type
682 		      && MSYMBOL_TYPE (&msymbol[hi - 1]) == want_type
683 		      && (MSYMBOL_SIZE (&msymbol[hi])
684 			  == MSYMBOL_SIZE (&msymbol[hi - 1]))
685 		      && (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])
686 			  == MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi - 1]))
687 		      && (MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi])
688 			  == MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi - 1])))
689 		    {
690 		      hi--;
691 		      continue;
692 		    }
693 
694 		  /* If the minimal symbol has a zero size, save it
695 		     but keep scanning backwards looking for one with
696 		     a non-zero size.  A zero size may mean that the
697 		     symbol isn't an object or function (e.g. a
698 		     label), or it may just mean that the size was not
699 		     specified.  */
700 		  if (MSYMBOL_SIZE (&msymbol[hi]) == 0)
701 		    {
702 		      if (best_zero_sized == -1)
703 			best_zero_sized = hi;
704 		      hi--;
705 		      continue;
706 		    }
707 
708 		  /* If we are past the end of the current symbol, try
709 		     the previous symbol if it has a larger overlapping
710 		     size.  This happens on i686-pc-linux-gnu with glibc;
711 		     the nocancel variants of system calls are inside
712 		     the cancellable variants, but both have sizes.  */
713 		  if (hi > 0
714 		      && MSYMBOL_SIZE (&msymbol[hi]) != 0
715 		      && pc >= (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])
716 				+ MSYMBOL_SIZE (&msymbol[hi]))
717 		      && pc < (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi - 1])
718 			       + MSYMBOL_SIZE (&msymbol[hi - 1])))
719 		    {
720 		      hi--;
721 		      continue;
722 		    }
723 
724 		  /* Otherwise, this symbol must be as good as we're going
725 		     to get.  */
726 		  break;
727 		}
728 
729 	      /* If HI has a zero size, and best_zero_sized is set,
730 		 then we had two or more zero-sized symbols; prefer
731 		 the first one we found (which may have a higher
732 		 address).  Also, if we ran off the end, be sure
733 		 to back up.  */
734 	      if (best_zero_sized != -1
735 		  && (hi < 0 || MSYMBOL_SIZE (&msymbol[hi]) == 0))
736 		hi = best_zero_sized;
737 
738 	      /* If the minimal symbol has a non-zero size, and this
739 		 PC appears to be outside the symbol's contents, then
740 		 refuse to use this symbol.  If we found a zero-sized
741 		 symbol with an address greater than this symbol's,
742 		 use that instead.  We assume that if symbols have
743 		 specified sizes, they do not overlap.  */
744 
745 	      if (hi >= 0
746 		  && MSYMBOL_SIZE (&msymbol[hi]) != 0
747 		  && pc >= (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])
748 			    + MSYMBOL_SIZE (&msymbol[hi])))
749 		{
750 		  if (best_zero_sized != -1)
751 		    hi = best_zero_sized;
752 		  else
753 		    /* Go on to the next object file.  */
754 		    continue;
755 		}
756 
757 	      /* The minimal symbol indexed by hi now is the best one in this
758 	         objfile's minimal symbol table.  See if it is the best one
759 	         overall.  */
760 
761 	      if (hi >= 0
762 		  && ((best_symbol == NULL) ||
763 		      (MSYMBOL_VALUE_RAW_ADDRESS (best_symbol) <
764 		       MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi]))))
765 		{
766 		  best_symbol = &msymbol[hi];
767 		  best_objfile = objfile;
768 		}
769 	    }
770 	}
771     }
772 
773   result.minsym = best_symbol;
774   result.objfile = best_objfile;
775   return result;
776 }
777 
778 struct bound_minimal_symbol
779 lookup_minimal_symbol_by_pc_section (CORE_ADDR pc, struct obj_section *section)
780 {
781   if (section == NULL)
782     {
783       /* NOTE: cagney/2004-01-27: This was using find_pc_mapped_section to
784 	 force the section but that (well unless you're doing overlay
785 	 debugging) always returns NULL making the call somewhat useless.  */
786       section = find_pc_section (pc);
787       if (section == NULL)
788 	{
789 	  struct bound_minimal_symbol result;
790 
791 	  memset (&result, 0, sizeof (result));
792 	  return result;
793 	}
794     }
795   return lookup_minimal_symbol_by_pc_section_1 (pc, section, 0);
796 }
797 
798 /* See minsyms.h.  */
799 
800 struct bound_minimal_symbol
801 lookup_minimal_symbol_by_pc (CORE_ADDR pc)
802 {
803   struct obj_section *section = find_pc_section (pc);
804 
805   if (section == NULL)
806     {
807       struct bound_minimal_symbol result;
808 
809       memset (&result, 0, sizeof (result));
810       return result;
811     }
812   return lookup_minimal_symbol_by_pc_section_1 (pc, section, 0);
813 }
814 
815 /* Return non-zero iff PC is in an STT_GNU_IFUNC function resolver.  */
816 
817 int
818 in_gnu_ifunc_stub (CORE_ADDR pc)
819 {
820   struct bound_minimal_symbol msymbol = lookup_minimal_symbol_by_pc (pc);
821 
822   return msymbol.minsym && MSYMBOL_TYPE (msymbol.minsym) == mst_text_gnu_ifunc;
823 }
824 
825 /* See elf_gnu_ifunc_resolve_addr for its real implementation.  */
826 
827 static CORE_ADDR
828 stub_gnu_ifunc_resolve_addr (struct gdbarch *gdbarch, CORE_ADDR pc)
829 {
830   error (_("GDB cannot resolve STT_GNU_IFUNC symbol at address %s without "
831 	   "the ELF support compiled in."),
832 	 paddress (gdbarch, pc));
833 }
834 
835 /* See elf_gnu_ifunc_resolve_name for its real implementation.  */
836 
837 static int
838 stub_gnu_ifunc_resolve_name (const char *function_name,
839 			     CORE_ADDR *function_address_p)
840 {
841   error (_("GDB cannot resolve STT_GNU_IFUNC symbol \"%s\" without "
842 	   "the ELF support compiled in."),
843 	 function_name);
844 }
845 
846 /* See elf_gnu_ifunc_resolver_stop for its real implementation.  */
847 
848 static void
849 stub_gnu_ifunc_resolver_stop (struct breakpoint *b)
850 {
851   internal_error (__FILE__, __LINE__,
852 		  _("elf_gnu_ifunc_resolver_stop cannot be reached."));
853 }
854 
855 /* See elf_gnu_ifunc_resolver_return_stop for its real implementation.  */
856 
857 static void
858 stub_gnu_ifunc_resolver_return_stop (struct breakpoint *b)
859 {
860   internal_error (__FILE__, __LINE__,
861 		  _("elf_gnu_ifunc_resolver_return_stop cannot be reached."));
862 }
863 
864 /* See elf_gnu_ifunc_fns for its real implementation.  */
865 
866 static const struct gnu_ifunc_fns stub_gnu_ifunc_fns =
867 {
868   stub_gnu_ifunc_resolve_addr,
869   stub_gnu_ifunc_resolve_name,
870   stub_gnu_ifunc_resolver_stop,
871   stub_gnu_ifunc_resolver_return_stop,
872 };
873 
874 /* A placeholder for &elf_gnu_ifunc_fns.  */
875 
876 const struct gnu_ifunc_fns *gnu_ifunc_fns_p = &stub_gnu_ifunc_fns;
877 
878 /* See minsyms.h.  */
879 
880 struct bound_minimal_symbol
881 lookup_minimal_symbol_and_objfile (const char *name)
882 {
883   struct bound_minimal_symbol result;
884   struct objfile *objfile;
885   unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
886 
887   ALL_OBJFILES (objfile)
888     {
889       struct minimal_symbol *msym;
890 
891       for (msym = objfile->per_bfd->msymbol_hash[hash];
892 	   msym != NULL;
893 	   msym = msym->hash_next)
894 	{
895 	  if (strcmp (MSYMBOL_LINKAGE_NAME (msym), name) == 0)
896 	    {
897 	      result.minsym = msym;
898 	      result.objfile = objfile;
899 	      return result;
900 	    }
901 	}
902     }
903 
904   memset (&result, 0, sizeof (result));
905   return result;
906 }
907 
908 
909 /* Return leading symbol character for a BFD.  If BFD is NULL,
910    return the leading symbol character from the main objfile.  */
911 
912 static int
913 get_symbol_leading_char (bfd *abfd)
914 {
915   if (abfd != NULL)
916     return bfd_get_symbol_leading_char (abfd);
917   if (symfile_objfile != NULL && symfile_objfile->obfd != NULL)
918     return bfd_get_symbol_leading_char (symfile_objfile->obfd);
919   return 0;
920 }
921 
922 /* See minsyms.h.  */
923 
924 void
925 init_minimal_symbol_collection (void)
926 {
927   msym_count = 0;
928   msym_bunch = NULL;
929   /* Note that presetting msym_bunch_index to BUNCH_SIZE causes the
930      first call to save a minimal symbol to allocate the memory for
931      the first bunch.  */
932   msym_bunch_index = BUNCH_SIZE;
933 }
934 
935 /* See minsyms.h.  */
936 
937 void
938 prim_record_minimal_symbol (const char *name, CORE_ADDR address,
939 			    enum minimal_symbol_type ms_type,
940 			    struct objfile *objfile)
941 {
942   int section;
943 
944   switch (ms_type)
945     {
946     case mst_text:
947     case mst_text_gnu_ifunc:
948     case mst_file_text:
949     case mst_solib_trampoline:
950       section = SECT_OFF_TEXT (objfile);
951       break;
952     case mst_data:
953     case mst_file_data:
954       section = SECT_OFF_DATA (objfile);
955       break;
956     case mst_bss:
957     case mst_file_bss:
958       section = SECT_OFF_BSS (objfile);
959       break;
960     default:
961       section = -1;
962     }
963 
964   prim_record_minimal_symbol_and_info (name, address, ms_type,
965 				       section, objfile);
966 }
967 
968 /* See minsyms.h.  */
969 
970 struct minimal_symbol *
971 prim_record_minimal_symbol_full (const char *name, int name_len, int copy_name,
972 				 CORE_ADDR address,
973 				 enum minimal_symbol_type ms_type,
974 				 int section,
975 				 struct objfile *objfile)
976 {
977   struct msym_bunch *newobj;
978   struct minimal_symbol *msymbol;
979 
980   /* Don't put gcc_compiled, __gnu_compiled_cplus, and friends into
981      the minimal symbols, because if there is also another symbol
982      at the same address (e.g. the first function of the file),
983      lookup_minimal_symbol_by_pc would have no way of getting the
984      right one.  */
985   if (ms_type == mst_file_text && name[0] == 'g'
986       && (strcmp (name, GCC_COMPILED_FLAG_SYMBOL) == 0
987 	  || strcmp (name, GCC2_COMPILED_FLAG_SYMBOL) == 0))
988     return (NULL);
989 
990   /* It's safe to strip the leading char here once, since the name
991      is also stored stripped in the minimal symbol table.  */
992   if (name[0] == get_symbol_leading_char (objfile->obfd))
993     {
994       ++name;
995       --name_len;
996     }
997 
998   if (ms_type == mst_file_text && startswith (name, "__gnu_compiled"))
999     return (NULL);
1000 
1001   if (msym_bunch_index == BUNCH_SIZE)
1002     {
1003       newobj = XCNEW (struct msym_bunch);
1004       msym_bunch_index = 0;
1005       newobj->next = msym_bunch;
1006       msym_bunch = newobj;
1007     }
1008   msymbol = &msym_bunch->contents[msym_bunch_index];
1009   MSYMBOL_SET_LANGUAGE (msymbol, language_auto,
1010 			&objfile->per_bfd->storage_obstack);
1011   MSYMBOL_SET_NAMES (msymbol, name, name_len, copy_name, objfile);
1012 
1013   SET_MSYMBOL_VALUE_ADDRESS (msymbol, address);
1014   MSYMBOL_SECTION (msymbol) = section;
1015 
1016   MSYMBOL_TYPE (msymbol) = ms_type;
1017   MSYMBOL_TARGET_FLAG_1 (msymbol) = 0;
1018   MSYMBOL_TARGET_FLAG_2 (msymbol) = 0;
1019   /* Do not use the SET_MSYMBOL_SIZE macro to initialize the size,
1020      as it would also set the has_size flag.  */
1021   msymbol->size = 0;
1022 
1023   /* The hash pointers must be cleared! If they're not,
1024      add_minsym_to_hash_table will NOT add this msymbol to the hash table.  */
1025   msymbol->hash_next = NULL;
1026   msymbol->demangled_hash_next = NULL;
1027 
1028   /* If we already read minimal symbols for this objfile, then don't
1029      ever allocate a new one.  */
1030   if (!objfile->per_bfd->minsyms_read)
1031     {
1032       msym_bunch_index++;
1033       objfile->per_bfd->n_minsyms++;
1034     }
1035   msym_count++;
1036   return msymbol;
1037 }
1038 
1039 /* See minsyms.h.  */
1040 
1041 struct minimal_symbol *
1042 prim_record_minimal_symbol_and_info (const char *name, CORE_ADDR address,
1043 				     enum minimal_symbol_type ms_type,
1044 				     int section,
1045 				     struct objfile *objfile)
1046 {
1047   return prim_record_minimal_symbol_full (name, strlen (name), 1,
1048 					  address, ms_type,
1049 					  section, objfile);
1050 }
1051 
1052 /* Compare two minimal symbols by address and return a signed result based
1053    on unsigned comparisons, so that we sort into unsigned numeric order.
1054    Within groups with the same address, sort by name.  */
1055 
1056 static int
1057 compare_minimal_symbols (const void *fn1p, const void *fn2p)
1058 {
1059   const struct minimal_symbol *fn1;
1060   const struct minimal_symbol *fn2;
1061 
1062   fn1 = (const struct minimal_symbol *) fn1p;
1063   fn2 = (const struct minimal_symbol *) fn2p;
1064 
1065   if (MSYMBOL_VALUE_RAW_ADDRESS (fn1) < MSYMBOL_VALUE_RAW_ADDRESS (fn2))
1066     {
1067       return (-1);		/* addr 1 is less than addr 2.  */
1068     }
1069   else if (MSYMBOL_VALUE_RAW_ADDRESS (fn1) > MSYMBOL_VALUE_RAW_ADDRESS (fn2))
1070     {
1071       return (1);		/* addr 1 is greater than addr 2.  */
1072     }
1073   else
1074     /* addrs are equal: sort by name */
1075     {
1076       const char *name1 = MSYMBOL_LINKAGE_NAME (fn1);
1077       const char *name2 = MSYMBOL_LINKAGE_NAME (fn2);
1078 
1079       if (name1 && name2)	/* both have names */
1080 	return strcmp (name1, name2);
1081       else if (name2)
1082 	return 1;		/* fn1 has no name, so it is "less".  */
1083       else if (name1)		/* fn2 has no name, so it is "less".  */
1084 	return -1;
1085       else
1086 	return (0);		/* Neither has a name, so they're equal.  */
1087     }
1088 }
1089 
1090 /* Discard the currently collected minimal symbols, if any.  If we wish
1091    to save them for later use, we must have already copied them somewhere
1092    else before calling this function.
1093 
1094    FIXME:  We could allocate the minimal symbol bunches on their own
1095    obstack and then simply blow the obstack away when we are done with
1096    it.  Is it worth the extra trouble though?  */
1097 
1098 static void
1099 do_discard_minimal_symbols_cleanup (void *arg)
1100 {
1101   struct msym_bunch *next;
1102 
1103   while (msym_bunch != NULL)
1104     {
1105       next = msym_bunch->next;
1106       xfree (msym_bunch);
1107       msym_bunch = next;
1108     }
1109 }
1110 
1111 /* See minsyms.h.  */
1112 
1113 struct cleanup *
1114 make_cleanup_discard_minimal_symbols (void)
1115 {
1116   return make_cleanup (do_discard_minimal_symbols_cleanup, 0);
1117 }
1118 
1119 
1120 
1121 /* Compact duplicate entries out of a minimal symbol table by walking
1122    through the table and compacting out entries with duplicate addresses
1123    and matching names.  Return the number of entries remaining.
1124 
1125    On entry, the table resides between msymbol[0] and msymbol[mcount].
1126    On exit, it resides between msymbol[0] and msymbol[result_count].
1127 
1128    When files contain multiple sources of symbol information, it is
1129    possible for the minimal symbol table to contain many duplicate entries.
1130    As an example, SVR4 systems use ELF formatted object files, which
1131    usually contain at least two different types of symbol tables (a
1132    standard ELF one and a smaller dynamic linking table), as well as
1133    DWARF debugging information for files compiled with -g.
1134 
1135    Without compacting, the minimal symbol table for gdb itself contains
1136    over a 1000 duplicates, about a third of the total table size.  Aside
1137    from the potential trap of not noticing that two successive entries
1138    identify the same location, this duplication impacts the time required
1139    to linearly scan the table, which is done in a number of places.  So we
1140    just do one linear scan here and toss out the duplicates.
1141 
1142    Note that we are not concerned here about recovering the space that
1143    is potentially freed up, because the strings themselves are allocated
1144    on the storage_obstack, and will get automatically freed when the symbol
1145    table is freed.  The caller can free up the unused minimal symbols at
1146    the end of the compacted region if their allocation strategy allows it.
1147 
1148    Also note we only go up to the next to last entry within the loop
1149    and then copy the last entry explicitly after the loop terminates.
1150 
1151    Since the different sources of information for each symbol may
1152    have different levels of "completeness", we may have duplicates
1153    that have one entry with type "mst_unknown" and the other with a
1154    known type.  So if the one we are leaving alone has type mst_unknown,
1155    overwrite its type with the type from the one we are compacting out.  */
1156 
1157 static int
1158 compact_minimal_symbols (struct minimal_symbol *msymbol, int mcount,
1159 			 struct objfile *objfile)
1160 {
1161   struct minimal_symbol *copyfrom;
1162   struct minimal_symbol *copyto;
1163 
1164   if (mcount > 0)
1165     {
1166       copyfrom = copyto = msymbol;
1167       while (copyfrom < msymbol + mcount - 1)
1168 	{
1169 	  if (MSYMBOL_VALUE_RAW_ADDRESS (copyfrom)
1170 	      == MSYMBOL_VALUE_RAW_ADDRESS ((copyfrom + 1))
1171 	      && MSYMBOL_SECTION (copyfrom) == MSYMBOL_SECTION (copyfrom + 1)
1172 	      && strcmp (MSYMBOL_LINKAGE_NAME (copyfrom),
1173 			 MSYMBOL_LINKAGE_NAME ((copyfrom + 1))) == 0)
1174 	    {
1175 	      if (MSYMBOL_TYPE ((copyfrom + 1)) == mst_unknown)
1176 		{
1177 		  MSYMBOL_TYPE ((copyfrom + 1)) = MSYMBOL_TYPE (copyfrom);
1178 		}
1179 	      copyfrom++;
1180 	    }
1181 	  else
1182 	    *copyto++ = *copyfrom++;
1183 	}
1184       *copyto++ = *copyfrom++;
1185       mcount = copyto - msymbol;
1186     }
1187   return (mcount);
1188 }
1189 
1190 /* Build (or rebuild) the minimal symbol hash tables.  This is necessary
1191    after compacting or sorting the table since the entries move around
1192    thus causing the internal minimal_symbol pointers to become jumbled.  */
1193 
1194 static void
1195 build_minimal_symbol_hash_tables (struct objfile *objfile)
1196 {
1197   int i;
1198   struct minimal_symbol *msym;
1199 
1200   /* Clear the hash tables.  */
1201   for (i = 0; i < MINIMAL_SYMBOL_HASH_SIZE; i++)
1202     {
1203       objfile->per_bfd->msymbol_hash[i] = 0;
1204       objfile->per_bfd->msymbol_demangled_hash[i] = 0;
1205     }
1206 
1207   /* Now, (re)insert the actual entries.  */
1208   for ((i = objfile->per_bfd->minimal_symbol_count,
1209 	msym = objfile->per_bfd->msymbols);
1210        i > 0;
1211        i--, msym++)
1212     {
1213       msym->hash_next = 0;
1214       add_minsym_to_hash_table (msym, objfile->per_bfd->msymbol_hash);
1215 
1216       msym->demangled_hash_next = 0;
1217       if (MSYMBOL_SEARCH_NAME (msym) != MSYMBOL_LINKAGE_NAME (msym))
1218 	add_minsym_to_demangled_hash_table (msym,
1219                                             objfile->per_bfd->msymbol_demangled_hash);
1220     }
1221 }
1222 
1223 /* Add the minimal symbols in the existing bunches to the objfile's official
1224    minimal symbol table.  In most cases there is no minimal symbol table yet
1225    for this objfile, and the existing bunches are used to create one.  Once
1226    in a while (for shared libraries for example), we add symbols (e.g. common
1227    symbols) to an existing objfile.
1228 
1229    Because of the way minimal symbols are collected, we generally have no way
1230    of knowing what source language applies to any particular minimal symbol.
1231    Specifically, we have no way of knowing if the minimal symbol comes from a
1232    C++ compilation unit or not.  So for the sake of supporting cached
1233    demangled C++ names, we have no choice but to try and demangle each new one
1234    that comes in.  If the demangling succeeds, then we assume it is a C++
1235    symbol and set the symbol's language and demangled name fields
1236    appropriately.  Note that in order to avoid unnecessary demanglings, and
1237    allocating obstack space that subsequently can't be freed for the demangled
1238    names, we mark all newly added symbols with language_auto.  After
1239    compaction of the minimal symbols, we go back and scan the entire minimal
1240    symbol table looking for these new symbols.  For each new symbol we attempt
1241    to demangle it, and if successful, record it as a language_cplus symbol
1242    and cache the demangled form on the symbol obstack.  Symbols which don't
1243    demangle are marked as language_unknown symbols, which inhibits future
1244    attempts to demangle them if we later add more minimal symbols.  */
1245 
1246 void
1247 install_minimal_symbols (struct objfile *objfile)
1248 {
1249   int bindex;
1250   int mcount;
1251   struct msym_bunch *bunch;
1252   struct minimal_symbol *msymbols;
1253   int alloc_count;
1254 
1255   if (objfile->per_bfd->minsyms_read)
1256     return;
1257 
1258   if (msym_count > 0)
1259     {
1260       if (symtab_create_debug)
1261 	{
1262 	  fprintf_unfiltered (gdb_stdlog,
1263 			      "Installing %d minimal symbols of objfile %s.\n",
1264 			      msym_count, objfile_name (objfile));
1265 	}
1266 
1267       /* Allocate enough space in the obstack, into which we will gather the
1268          bunches of new and existing minimal symbols, sort them, and then
1269          compact out the duplicate entries.  Once we have a final table,
1270          we will give back the excess space.  */
1271 
1272       alloc_count = msym_count + objfile->per_bfd->minimal_symbol_count + 1;
1273       obstack_blank (&objfile->per_bfd->storage_obstack,
1274 		     alloc_count * sizeof (struct minimal_symbol));
1275       msymbols = (struct minimal_symbol *)
1276 	obstack_base (&objfile->per_bfd->storage_obstack);
1277 
1278       /* Copy in the existing minimal symbols, if there are any.  */
1279 
1280       if (objfile->per_bfd->minimal_symbol_count)
1281 	memcpy ((char *) msymbols, (char *) objfile->per_bfd->msymbols,
1282 	    objfile->per_bfd->minimal_symbol_count * sizeof (struct minimal_symbol));
1283 
1284       /* Walk through the list of minimal symbol bunches, adding each symbol
1285          to the new contiguous array of symbols.  Note that we start with the
1286          current, possibly partially filled bunch (thus we use the current
1287          msym_bunch_index for the first bunch we copy over), and thereafter
1288          each bunch is full.  */
1289 
1290       mcount = objfile->per_bfd->minimal_symbol_count;
1291 
1292       for (bunch = msym_bunch; bunch != NULL; bunch = bunch->next)
1293 	{
1294 	  for (bindex = 0; bindex < msym_bunch_index; bindex++, mcount++)
1295 	    msymbols[mcount] = bunch->contents[bindex];
1296 	  msym_bunch_index = BUNCH_SIZE;
1297 	}
1298 
1299       /* Sort the minimal symbols by address.  */
1300 
1301       qsort (msymbols, mcount, sizeof (struct minimal_symbol),
1302 	     compare_minimal_symbols);
1303 
1304       /* Compact out any duplicates, and free up whatever space we are
1305          no longer using.  */
1306 
1307       mcount = compact_minimal_symbols (msymbols, mcount, objfile);
1308 
1309       obstack_blank_fast (&objfile->per_bfd->storage_obstack,
1310 	       (mcount + 1 - alloc_count) * sizeof (struct minimal_symbol));
1311       msymbols = (struct minimal_symbol *)
1312 	obstack_finish (&objfile->per_bfd->storage_obstack);
1313 
1314       /* We also terminate the minimal symbol table with a "null symbol",
1315          which is *not* included in the size of the table.  This makes it
1316          easier to find the end of the table when we are handed a pointer
1317          to some symbol in the middle of it.  Zero out the fields in the
1318          "null symbol" allocated at the end of the array.  Note that the
1319          symbol count does *not* include this null symbol, which is why it
1320          is indexed by mcount and not mcount-1.  */
1321 
1322       memset (&msymbols[mcount], 0, sizeof (struct minimal_symbol));
1323 
1324       /* Attach the minimal symbol table to the specified objfile.
1325          The strings themselves are also located in the storage_obstack
1326          of this objfile.  */
1327 
1328       objfile->per_bfd->minimal_symbol_count = mcount;
1329       objfile->per_bfd->msymbols = msymbols;
1330 
1331       /* Now build the hash tables; we can't do this incrementally
1332          at an earlier point since we weren't finished with the obstack
1333 	 yet.  (And if the msymbol obstack gets moved, all the internal
1334 	 pointers to other msymbols need to be adjusted.)  */
1335       build_minimal_symbol_hash_tables (objfile);
1336     }
1337 }
1338 
1339 /* See minsyms.h.  */
1340 
1341 void
1342 terminate_minimal_symbol_table (struct objfile *objfile)
1343 {
1344   if (! objfile->per_bfd->msymbols)
1345     objfile->per_bfd->msymbols
1346       = ((struct minimal_symbol *)
1347 	 obstack_alloc (&objfile->per_bfd->storage_obstack,
1348 			sizeof (struct minimal_symbol)));
1349 
1350   {
1351     struct minimal_symbol *m
1352       = &objfile->per_bfd->msymbols[objfile->per_bfd->minimal_symbol_count];
1353 
1354     memset (m, 0, sizeof (*m));
1355     /* Don't rely on these enumeration values being 0's.  */
1356     MSYMBOL_TYPE (m) = mst_unknown;
1357     MSYMBOL_SET_LANGUAGE (m, language_unknown,
1358 			  &objfile->per_bfd->storage_obstack);
1359   }
1360 }
1361 
1362 /* Check if PC is in a shared library trampoline code stub.
1363    Return minimal symbol for the trampoline entry or NULL if PC is not
1364    in a trampoline code stub.  */
1365 
1366 static struct minimal_symbol *
1367 lookup_solib_trampoline_symbol_by_pc (CORE_ADDR pc)
1368 {
1369   struct obj_section *section = find_pc_section (pc);
1370   struct bound_minimal_symbol msymbol;
1371 
1372   if (section == NULL)
1373     return NULL;
1374   msymbol = lookup_minimal_symbol_by_pc_section_1 (pc, section, 1);
1375 
1376   if (msymbol.minsym != NULL
1377       && MSYMBOL_TYPE (msymbol.minsym) == mst_solib_trampoline)
1378     return msymbol.minsym;
1379   return NULL;
1380 }
1381 
1382 /* If PC is in a shared library trampoline code stub, return the
1383    address of the `real' function belonging to the stub.
1384    Return 0 if PC is not in a trampoline code stub or if the real
1385    function is not found in the minimal symbol table.
1386 
1387    We may fail to find the right function if a function with the
1388    same name is defined in more than one shared library, but this
1389    is considered bad programming style.  We could return 0 if we find
1390    a duplicate function in case this matters someday.  */
1391 
1392 CORE_ADDR
1393 find_solib_trampoline_target (struct frame_info *frame, CORE_ADDR pc)
1394 {
1395   struct objfile *objfile;
1396   struct minimal_symbol *msymbol;
1397   struct minimal_symbol *tsymbol = lookup_solib_trampoline_symbol_by_pc (pc);
1398 
1399   if (tsymbol != NULL)
1400     {
1401       ALL_MSYMBOLS (objfile, msymbol)
1402       {
1403 	if ((MSYMBOL_TYPE (msymbol) == mst_text
1404 	    || MSYMBOL_TYPE (msymbol) == mst_text_gnu_ifunc)
1405 	    && strcmp (MSYMBOL_LINKAGE_NAME (msymbol),
1406 		       MSYMBOL_LINKAGE_NAME (tsymbol)) == 0)
1407 	  return MSYMBOL_VALUE_ADDRESS (objfile, msymbol);
1408 
1409 	/* Also handle minimal symbols pointing to function descriptors.  */
1410 	if (MSYMBOL_TYPE (msymbol) == mst_data
1411 	    && strcmp (MSYMBOL_LINKAGE_NAME (msymbol),
1412 		       MSYMBOL_LINKAGE_NAME (tsymbol)) == 0)
1413 	  {
1414 	    CORE_ADDR func;
1415 
1416 	    func = gdbarch_convert_from_func_ptr_addr
1417 		    (get_objfile_arch (objfile),
1418 		     MSYMBOL_VALUE_ADDRESS (objfile, msymbol),
1419 		     &current_target);
1420 
1421 	    /* Ignore data symbols that are not function descriptors.  */
1422 	    if (func != MSYMBOL_VALUE_ADDRESS (objfile, msymbol))
1423 	      return func;
1424 	  }
1425       }
1426     }
1427   return 0;
1428 }
1429 
1430 /* See minsyms.h.  */
1431 
1432 CORE_ADDR
1433 minimal_symbol_upper_bound (struct bound_minimal_symbol minsym)
1434 {
1435   int i;
1436   short section;
1437   struct obj_section *obj_section;
1438   CORE_ADDR result;
1439   struct minimal_symbol *msymbol;
1440 
1441   gdb_assert (minsym.minsym != NULL);
1442 
1443   /* If the minimal symbol has a size, use it.  Otherwise use the
1444      lesser of the next minimal symbol in the same section, or the end
1445      of the section, as the end of the function.  */
1446 
1447   if (MSYMBOL_SIZE (minsym.minsym) != 0)
1448     return BMSYMBOL_VALUE_ADDRESS (minsym) + MSYMBOL_SIZE (minsym.minsym);
1449 
1450   /* Step over other symbols at this same address, and symbols in
1451      other sections, to find the next symbol in this section with a
1452      different address.  */
1453 
1454   msymbol = minsym.minsym;
1455   section = MSYMBOL_SECTION (msymbol);
1456   for (i = 1; MSYMBOL_LINKAGE_NAME (msymbol + i) != NULL; i++)
1457     {
1458       if ((MSYMBOL_VALUE_RAW_ADDRESS (msymbol + i)
1459 	   != MSYMBOL_VALUE_RAW_ADDRESS (msymbol))
1460 	  && MSYMBOL_SECTION (msymbol + i) == section)
1461 	break;
1462     }
1463 
1464   obj_section = MSYMBOL_OBJ_SECTION (minsym.objfile, minsym.minsym);
1465   if (MSYMBOL_LINKAGE_NAME (msymbol + i) != NULL
1466       && (MSYMBOL_VALUE_ADDRESS (minsym.objfile, msymbol + i)
1467 	  < obj_section_endaddr (obj_section)))
1468     result = MSYMBOL_VALUE_ADDRESS (minsym.objfile, msymbol + i);
1469   else
1470     /* We got the start address from the last msymbol in the objfile.
1471        So the end address is the end of the section.  */
1472     result = obj_section_endaddr (obj_section);
1473 
1474   return result;
1475 }
1476