gdb/block.c

   1 /* Block-related functions for the GNU debugger, GDB.
   2
   3    Copyright (C) 2003, 2007-2012 Free Software Foundation, Inc.
   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 #include "defs.h"
  21 #include "block.h"
  22 #include "symtab.h"
  23 #include "symfile.h"
  24 #include "gdb_obstack.h"
  25 #include "cp-support.h"
  26 #include "addrmap.h"
  27 #include "gdbtypes.h"
  28 #include "exceptions.h"
  29
  30 /* This is used by struct block to store namespace-related info for
  31    C++ files, namely using declarations and the current namespace in
  32    scope.  */
  33
  34 struct block_namespace_info
  35 {
  36   const char *scope;
  37   struct using_direct *using;
  38 };
  39
  40 static void block_initialize_namespace (struct block *block,
  41                                         struct obstack *obstack);
  42
  43 /* Return Nonzero if block a is lexically nested within block b,
  44    or if a and b have the same pc range.
  45    Return zero otherwise.  */
  46
  47 int
  48 contained_in (const struct block *a, const struct block *b)
  49 {
  50   if (!a || !b)
  51     return 0;
  52
  53   do
  54     {
  55       if (a == b)
  56         return 1;
  57       /* If A is a function block, then A cannot be contained in B,
  58          except if A was inlined.  */
  59       if (BLOCK_FUNCTION (a) != NULL && !block_inlined_p (a))
  60         return 0;
  61       a = BLOCK_SUPERBLOCK (a);
  62     }
  63   while (a != NULL);
  64
  65   return 0;
  66 }
  67
  68
  69 /* Return the symbol for the function which contains a specified
  70    lexical block, described by a struct block BL.  The return value
  71    will not be an inlined function; the containing function will be
  72    returned instead.  */
  73
  74 struct symbol *
  75 block_linkage_function (const struct block *bl)
  76 {
  77   while ((BLOCK_FUNCTION (bl) == NULL || block_inlined_p (bl))
  78          && BLOCK_SUPERBLOCK (bl) != NULL)
  79     bl = BLOCK_SUPERBLOCK (bl);
  80
  81   return BLOCK_FUNCTION (bl);
  82 }
  83
  84 /* Return the symbol for the function which contains a specified
  85    block, described by a struct block BL.  The return value will be
  86    the closest enclosing function, which might be an inline
  87    function.  */
  88
  89 struct symbol *
  90 block_containing_function (const struct block *bl)
  91 {
  92   while (BLOCK_FUNCTION (bl) == NULL && BLOCK_SUPERBLOCK (bl) != NULL)
  93     bl = BLOCK_SUPERBLOCK (bl);
  94
  95   return BLOCK_FUNCTION (bl);
  96 }
  97
  98 /* Return one if BL represents an inlined function.  */
  99
 100 int
 101 block_inlined_p (const struct block *bl)
 102 {
 103   return BLOCK_FUNCTION (bl) != NULL && SYMBOL_INLINED (BLOCK_FUNCTION (bl));
 104 }
 105
 106 /* Return the blockvector immediately containing the innermost lexical
 107    block containing the specified pc value and section, or 0 if there
 108    is none.  PBLOCK is a pointer to the block.  If PBLOCK is NULL, we
 109    don't pass this information back to the caller.  */
 110
 111 struct blockvector *
 112 blockvector_for_pc_sect (CORE_ADDR pc, struct obj_section *section,
 113                          struct block **pblock, struct symtab *symtab)
 114 {
 115   struct block *b;
 116   int bot, top, half;
 117   struct blockvector *bl;
 118
 119   if (symtab == 0)              /* if no symtab specified by caller */
 120     {
 121       /* First search all symtabs for one whose file contains our pc */
 122       symtab = find_pc_sect_symtab (pc, section);
 123       if (symtab == 0)
 124         return 0;
 125     }
 126
 127   bl = BLOCKVECTOR (symtab);
 128
 129   /* Then search that symtab for the smallest block that wins.  */
 130
 131   /* If we have an addrmap mapping code addresses to blocks, then use
 132      that.  */
 133   if (BLOCKVECTOR_MAP (bl))
 134     {
 135       b = addrmap_find (BLOCKVECTOR_MAP (bl), pc);
 136       if (b)
 137         {
 138           if (pblock)
 139             *pblock = b;
 140           return bl;
 141         }
 142       else
 143         return 0;
 144     }
 145
 146
 147   /* Otherwise, use binary search to find the last block that starts
 148      before PC.  */
 149   bot = 0;
 150   top = BLOCKVECTOR_NBLOCKS (bl);
 151
 152   while (top - bot > 1)
 153     {
 154       half = (top - bot + 1) >> 1;
 155       b = BLOCKVECTOR_BLOCK (bl, bot + half);
 156       if (BLOCK_START (b) <= pc)
 157         bot += half;
 158       else
 159         top = bot + half;
 160     }
 161
 162   /* Now search backward for a block that ends after PC.  */
 163
 164   while (bot >= 0)
 165     {
 166       b = BLOCKVECTOR_BLOCK (bl, bot);
 167       if (BLOCK_END (b) > pc)
 168         {
 169           if (pblock)
 170             *pblock = b;
 171           return bl;
 172         }
 173       bot--;
 174     }
 175   return 0;
 176 }
 177
 178 /* Return call_site for specified PC in GDBARCH.  PC must match exactly, it
 179    must be the next instruction after call (or after tail call jump).  Throw
 180    NO_ENTRY_VALUE_ERROR otherwise.  This function never returns NULL.  */
 181
 182 struct call_site *
 183 call_site_for_pc (struct gdbarch *gdbarch, CORE_ADDR pc)
 184 {
 185   struct symtab *symtab;
 186   void **slot = NULL;
 187
 188   /* -1 as tail call PC can be already after the compilation unit range.  */
 189   symtab = find_pc_symtab (pc - 1);
 190
 191   if (symtab != NULL && symtab->call_site_htab != NULL)
 192     slot = htab_find_slot (symtab->call_site_htab, &pc, NO_INSERT);
 193
 194   if (slot == NULL)
 195     {
 196       struct minimal_symbol *msym = lookup_minimal_symbol_by_pc (pc);
 197
 198       /* DW_TAG_gnu_call_site will be missing just if GCC could not determine
 199          the call target.  */
 200       throw_error (NO_ENTRY_VALUE_ERROR,
 201                    _("DW_OP_GNU_entry_value resolving cannot find "
 202                      "DW_TAG_GNU_call_site %s in %s"),
 203                    paddress (gdbarch, pc),
 204                    msym == NULL ? "???" : SYMBOL_PRINT_NAME (msym));
 205     }
 206
 207   return *slot;
 208 }
 209
 210 /* Return the blockvector immediately containing the innermost lexical block
 211    containing the specified pc value, or 0 if there is none.
 212    Backward compatibility, no section.  */
 213
 214 struct blockvector *
 215 blockvector_for_pc (CORE_ADDR pc, struct block **pblock)
 216 {
 217   return blockvector_for_pc_sect (pc, find_pc_mapped_section (pc),
 218                                   pblock, NULL);
 219 }
 220
 221 /* Return the innermost lexical block containing the specified pc value
 222    in the specified section, or 0 if there is none.  */
 223
 224 struct block *
 225 block_for_pc_sect (CORE_ADDR pc, struct obj_section *section)
 226 {
 227   struct blockvector *bl;
 228   struct block *b;
 229
 230   bl = blockvector_for_pc_sect (pc, section, &b, NULL);
 231   if (bl)
 232     return b;
 233   return 0;
 234 }
 235
 236 /* Return the innermost lexical block containing the specified pc value,
 237    or 0 if there is none.  Backward compatibility, no section.  */
 238
 239 struct block *
 240 block_for_pc (CORE_ADDR pc)
 241 {
 242   return block_for_pc_sect (pc, find_pc_mapped_section (pc));
 243 }
 244
 245 /* Now come some functions designed to deal with C++ namespace issues.
 246    The accessors are safe to use even in the non-C++ case.  */
 247
 248 /* This returns the namespace that BLOCK is enclosed in, or "" if it
 249    isn't enclosed in a namespace at all.  This travels the chain of
 250    superblocks looking for a scope, if necessary.  */
 251
 252 const char *
 253 block_scope (const struct block *block)
 254 {
 255   for (; block != NULL; block = BLOCK_SUPERBLOCK (block))
 256     {
 257       if (BLOCK_NAMESPACE (block) != NULL
 258           && BLOCK_NAMESPACE (block)->scope != NULL)
 259         return BLOCK_NAMESPACE (block)->scope;
 260     }
 261
 262   return "";
 263 }
 264
 265 /* Set BLOCK's scope member to SCOPE; if needed, allocate memory via
 266    OBSTACK.  (It won't make a copy of SCOPE, however, so that already
 267    has to be allocated correctly.)  */
 268
 269 void
 270 block_set_scope (struct block *block, const char *scope,
 271                  struct obstack *obstack)
 272 {
 273   block_initialize_namespace (block, obstack);
 274
 275   BLOCK_NAMESPACE (block)->scope = scope;
 276 }
 277
 278 /* This returns the using directives list associated with BLOCK, if
 279    any.  */
 280
 281 struct using_direct *
 282 block_using (const struct block *block)
 283 {
 284   if (block == NULL || BLOCK_NAMESPACE (block) == NULL)
 285     return NULL;
 286   else
 287     return BLOCK_NAMESPACE (block)->using;
 288 }
 289
 290 /* Set BLOCK's using member to USING; if needed, allocate memory via
 291    OBSTACK.  (It won't make a copy of USING, however, so that already
 292    has to be allocated correctly.)  */
 293
 294 void
 295 block_set_using (struct block *block,
 296                  struct using_direct *using,
 297                  struct obstack *obstack)
 298 {
 299   block_initialize_namespace (block, obstack);
 300
 301   BLOCK_NAMESPACE (block)->using = using;
 302 }
 303
 304 /* If BLOCK_NAMESPACE (block) is NULL, allocate it via OBSTACK and
 305    ititialize its members to zero.  */
 306
 307 static void
 308 block_initialize_namespace (struct block *block, struct obstack *obstack)
 309 {
 310   if (BLOCK_NAMESPACE (block) == NULL)
 311     {
 312       BLOCK_NAMESPACE (block)
 313         = obstack_alloc (obstack, sizeof (struct block_namespace_info));
 314       BLOCK_NAMESPACE (block)->scope = NULL;
 315       BLOCK_NAMESPACE (block)->using = NULL;
 316     }
 317 }
 318
 319 /* Return the static block associated to BLOCK.  Return NULL if block
 320    is NULL or if block is a global block.  */
 321
 322 const struct block *
 323 block_static_block (const struct block *block)
 324 {
 325   if (block == NULL || BLOCK_SUPERBLOCK (block) == NULL)
 326     return NULL;
 327
 328   while (BLOCK_SUPERBLOCK (BLOCK_SUPERBLOCK (block)) != NULL)
 329     block = BLOCK_SUPERBLOCK (block);
 330
 331   return block;
 332 }
 333
 334 /* Return the static block associated to BLOCK.  Return NULL if block
 335    is NULL.  */
 336
 337 const struct block *
 338 block_global_block (const struct block *block)
 339 {
 340   if (block == NULL)
 341     return NULL;
 342
 343   while (BLOCK_SUPERBLOCK (block) != NULL)
 344     block = BLOCK_SUPERBLOCK (block);
 345
 346   return block;
 347 }
 348
 349 /* Allocate a block on OBSTACK, and initialize its elements to
 350    zero/NULL.  This is useful for creating "dummy" blocks that don't
 351    correspond to actual source files.
 352
 353    Warning: it sets the block's BLOCK_DICT to NULL, which isn't a
 354    valid value.  If you really don't want the block to have a
 355    dictionary, then you should subsequently set its BLOCK_DICT to
 356    dict_create_linear (obstack, NULL).  */
 357
 358 struct block *
 359 allocate_block (struct obstack *obstack)
 360 {
 361   struct block *bl = obstack_alloc (obstack, sizeof (struct block));
 362
 363   BLOCK_START (bl) = 0;
 364   BLOCK_END (bl) = 0;
 365   BLOCK_FUNCTION (bl) = NULL;
 366   BLOCK_SUPERBLOCK (bl) = NULL;
 367   BLOCK_DICT (bl) = NULL;
 368   BLOCK_NAMESPACE (bl) = NULL;
 369
 370   return bl;
 371 }