gdb/psympriv.h

   1 /* Private partial symbol table definitions.
   2
   3    Copyright (C) 2009-2021 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 #ifndef PSYMPRIV_H
  21 #define PSYMPRIV_H
  22
  23 #include "psymtab.h"
  24 #include "objfiles.h"
  25 #include "gdbsupport/gdb_string_view.h"
  26
  27 /* A partial_symbol records the name, domain, and address class of
  28    symbols whose types we have not parsed yet.  For functions, it also
  29    contains their memory address, so we can find them from a PC value.
  30    Each partial_symbol sits in a partial_symtab, all of which are chained
  31    on a  partial symtab list and which points to the corresponding
  32    normal symtab once the partial_symtab has been referenced.  */
  33
  34 /* This structure is space critical.  See space comments at the top of
  35    symtab.h.  */
  36
  37 struct partial_symbol
  38 {
  39   /* Return the section for this partial symbol, or nullptr if no
  40      section has been set.  */
  41   struct obj_section *obj_section (struct objfile *objfile) const
  42   {
  43     return ginfo.obj_section (objfile);
  44   }
  45
  46   /* Return the unrelocated address of this partial symbol.  */
  47   CORE_ADDR unrelocated_address () const
  48   {
  49     return ginfo.value.address;
  50   }
  51
  52   /* Return the address of this partial symbol, relocated according to
  53      the offsets provided in OBJFILE.  */
  54   CORE_ADDR address (const struct objfile *objfile) const
  55   {
  56     return (ginfo.value.address
  57             + objfile->section_offsets[ginfo.section_index ()]);
  58   }
  59
  60   /* Set the address of this partial symbol.  The address must be
  61      unrelocated.  */
  62   void set_unrelocated_address (CORE_ADDR addr)
  63   {
  64     ginfo.value.address = addr;
  65   }
  66
  67   /* Note that partial_symbol does not derive from general_symbol_info
  68      due to the bcache.  See add_psymbol_to_bcache.  */
  69
  70   struct general_symbol_info ginfo;
  71
  72   /* Name space code.  */
  73
  74   ENUM_BITFIELD(domain_enum_tag) domain : SYMBOL_DOMAIN_BITS;
  75
  76   /* Address class (for info_symbols).  Note that we don't allow
  77      synthetic "aclass" values here at present, simply because there's
  78      no need.  */
  79
  80   ENUM_BITFIELD(address_class) aclass : SYMBOL_ACLASS_BITS;
  81 };
  82
  83 /* A convenience enum to give names to some constants used when
  84    searching psymtabs.  This is internal to psymtab and should not be
  85    used elsewhere.  */
  86
  87 enum psymtab_search_status
  88   {
  89     PST_NOT_SEARCHED,
  90     PST_SEARCHED_AND_FOUND,
  91     PST_SEARCHED_AND_NOT_FOUND
  92   };
  93
  94 /* Specify whether a partial psymbol should be allocated on the global
  95    list or the static list.  */
  96
  97 enum class psymbol_placement
  98 {
  99   STATIC,
 100   GLOBAL
 101 };
 102
 103 /* Each source file that has not been fully read in is represented by
 104    a partial_symtab.  This contains the information on where in the
 105    executable the debugging symbols for a specific file are, and a
 106    list of names of global symbols which are located in this file.
 107    They are all chained on partial symtab lists.
 108
 109    Even after the source file has been read into a symtab, the
 110    partial_symtab remains around.  */
 111
 112 struct partial_symtab
 113 {
 114   /* Allocate a new partial symbol table associated with OBJFILE.
 115      FILENAME (which must be non-NULL) is the filename of this partial
 116      symbol table; it is copied into the appropriate storage.  The
 117      partial symtab will also be installed using
 118      psymtab_storage::install.  */
 119
 120   partial_symtab (const char *filename, struct objfile *objfile)
 121     ATTRIBUTE_NONNULL (2) ATTRIBUTE_NONNULL (3);
 122
 123   /* Like the above, but also sets the initial text low and text high
 124      from the ADDR argument, and sets the global- and
 125      static-offsets.  */
 126
 127   partial_symtab (const char *filename, struct objfile *objfile,
 128                   CORE_ADDR addr)
 129     ATTRIBUTE_NONNULL (2) ATTRIBUTE_NONNULL (3);
 130
 131   virtual ~partial_symtab ()
 132   {
 133   }
 134
 135   /* Psymtab expansion is done in two steps:
 136      - a call to read_symtab
 137      - while that call is in progress, calls to expand_psymtab can be made,
 138        both for this psymtab, and its dependencies.
 139      This makes a distinction between a toplevel psymtab (for which both
 140      read_symtab and expand_psymtab will be called) and a non-toplevel
 141      psymtab (for which only expand_psymtab will be called). The
 142      distinction can be used f.i. to do things before and after all
 143      dependencies of a top-level psymtab have been expanded.
 144
 145      Read the full symbol table corresponding to this partial symbol
 146      table.  Typically calls expand_psymtab.  */
 147   virtual void read_symtab (struct objfile *) = 0;
 148
 149   /* Expand the full symbol table for this partial symbol table.  Typically
 150      calls expand_dependencies.  */
 151   virtual void expand_psymtab (struct objfile *) = 0;
 152
 153   /* Ensure that all the dependencies are read in.  Calls
 154      expand_psymtab for each non-shared dependency.  */
 155   void expand_dependencies (struct objfile *);
 156
 157   /* Return true if the symtab corresponding to this psymtab has been
 158      read in in the context of this objfile.  */
 159   virtual bool readin_p (struct objfile *) const = 0;
 160
 161   /* Return a pointer to the compunit allocated for this source file
 162      in the context of this objfile.
 163
 164      Return nullptr if the compunit was not read in or if there was no
 165      symtab.  */
 166   virtual struct compunit_symtab *get_compunit_symtab
 167     (struct objfile *) const = 0;
 168
 169   /* Return the raw low text address of this partial_symtab.  */
 170   CORE_ADDR raw_text_low () const
 171   {
 172     return m_text_low;
 173   }
 174
 175   /* Return the raw high text address of this partial_symtab.  */
 176   CORE_ADDR raw_text_high () const
 177   {
 178     return m_text_high;
 179   }
 180
 181   /* Return the relocated low text address of this partial_symtab.  */
 182   CORE_ADDR text_low (struct objfile *objfile) const
 183   {
 184     return m_text_low + objfile->text_section_offset ();
 185   }
 186
 187   /* Return the relocated high text address of this partial_symtab.  */
 188   CORE_ADDR text_high (struct objfile *objfile) const
 189   {
 190     return m_text_high + objfile->text_section_offset ();
 191   }
 192
 193   /* Set the low text address of this partial_symtab.  */
 194   void set_text_low (CORE_ADDR addr)
 195   {
 196     m_text_low = addr;
 197     text_low_valid = 1;
 198   }
 199
 200   /* Set the hight text address of this partial_symtab.  */
 201   void set_text_high (CORE_ADDR addr)
 202   {
 203     m_text_high = addr;
 204     text_high_valid = 1;
 205   }
 206
 207   /* Return true if this symtab is empty -- meaning that it contains
 208      no symbols.  It may still have dependencies.  */
 209   bool empty () const
 210   {
 211     return global_psymbols.empty () && static_psymbols.empty ();
 212   }
 213
 214   /* Add a symbol to this partial symbol table of OBJFILE.
 215
 216      If COPY_NAME is true, make a copy of NAME, otherwise use the passed
 217      reference.
 218
 219      THECLASS is the type of symbol.
 220
 221      SECTION is the index of the section of OBJFILE in which the symbol is found.
 222
 223      WHERE determines whether the symbol goes in the list of static or global
 224      partial symbols.
 225
 226      COREADDR is the address of the symbol.  For partial symbols that don't have
 227      an address, zero is passed.
 228
 229      LANGUAGE is the language from which the symbol originates.  This will
 230      influence, amongst other things, how the symbol name is demangled. */
 231
 232   void add_psymbol (gdb::string_view name,
 233                     bool copy_name, domain_enum domain,
 234                     enum address_class theclass,
 235                     short section,
 236                     psymbol_placement where,
 237                     CORE_ADDR coreaddr,
 238                     enum language language,
 239                     struct objfile *objfile);
 240
 241   /* Add a symbol to this partial symbol table of OBJFILE.  The psymbol
 242      must be fully constructed, and the names must be set and intern'd
 243      as appropriate.  */
 244
 245   void add_psymbol (const partial_symbol &psym,
 246                     psymbol_placement where,
 247                     struct objfile *objfile);
 248
 249
 250   /* Indicate that this partial symtab is complete.  */
 251
 252   void end ();
 253
 254   /* Chain of all existing partial symtabs.  */
 255
 256   struct partial_symtab *next = nullptr;
 257
 258   /* Name of the source file which this partial_symtab defines,
 259      or if the psymtab is anonymous then a descriptive name for
 260      debugging purposes, or "".  It must not be NULL.  */
 261
 262   const char *filename = nullptr;
 263
 264   /* Full path of the source file.  NULL if not known.  */
 265
 266   char *fullname = nullptr;
 267
 268   /* Directory in which it was compiled, or NULL if we don't know.  */
 269
 270   const char *dirname = nullptr;
 271
 272   /* Range of text addresses covered by this file; texthigh is the
 273      beginning of the next section.  Do not use if PSYMTABS_ADDRMAP_SUPPORTED
 274      is set.  Do not refer directly to these fields.  Instead, use the
 275      accessors.  The validity of these fields is determined by the
 276      text_low_valid and text_high_valid fields; these are located later
 277      in this structure for better packing.  */
 278
 279   CORE_ADDR m_text_low = 0;
 280   CORE_ADDR m_text_high = 0;
 281
 282   /* If NULL, this is an ordinary partial symbol table.
 283
 284      If non-NULL, this holds a single includer of this partial symbol
 285      table, and this partial symbol table is a shared one.
 286
 287      A shared psymtab is one that is referenced by multiple other
 288      psymtabs, and which conceptually has its contents directly
 289      included in those.
 290
 291      Shared psymtabs have special semantics.  When a search finds a
 292      symbol in a shared table, we instead return one of the non-shared
 293      tables that include this one.
 294
 295      A shared psymtabs can be referred to by other shared ones.
 296
 297      The psymtabs that refer to a shared psymtab will list the shared
 298      psymtab in their 'dependencies' array.
 299
 300      In DWARF terms, a shared psymtab is a DW_TAG_partial_unit; but
 301      of course using a name based on that would be too confusing, so
 302      "shared" was chosen instead.
 303
 304      Only a single user is needed because, when expanding a shared
 305      psymtab, we only need to expand its "canonical" non-shared user.
 306      The choice of which one should be canonical is left to the
 307      debuginfo reader; it can be arbitrary.  */
 308
 309   struct partial_symtab *user = nullptr;
 310
 311   /* Array of pointers to all of the partial_symtab's which this one
 312      depends on.  Since this array can only be set to previous or
 313      the current (?) psymtab, this dependency tree is guaranteed not
 314      to have any loops.  "depends on" means that symbols must be read
 315      for the dependencies before being read for this psymtab; this is
 316      for type references in stabs, where if foo.c includes foo.h, declarations
 317      in foo.h may use type numbers defined in foo.c.  For other debugging
 318      formats there may be no need to use dependencies.  */
 319
 320   struct partial_symtab **dependencies = nullptr;
 321
 322   int number_of_dependencies = 0;
 323
 324   /* Global symbol list.  This list will be sorted after readin to
 325      improve access.  Binary search will be the usual method of
 326      finding a symbol within it.  */
 327
 328   std::vector<partial_symbol *> global_psymbols;
 329
 330   /* Static symbol list.  This list will *not* be sorted after readin;
 331      to find a symbol in it, exhaustive search must be used.  This is
 332      reasonable because searches through this list will eventually
 333      lead to either the read in of a files symbols for real (assumed
 334      to take a *lot* of time; check) or an error (and we don't care
 335      how long errors take).  */
 336
 337   std::vector<partial_symbol *> static_psymbols;
 338
 339   /* True iff objfile->psymtabs_addrmap is properly populated for this
 340      partial_symtab.  For discontiguous overlapping psymtabs is the only usable
 341      info in PSYMTABS_ADDRMAP.  */
 342
 343   bool psymtabs_addrmap_supported = false;
 344
 345   /* True if the name of this partial symtab is not a source file name.  */
 346
 347   bool anonymous = false;
 348
 349   /* A flag that is temporarily used when searching psymtabs.  */
 350
 351   ENUM_BITFIELD (psymtab_search_status) searched_flag : 2;
 352
 353   /* Validity of the m_text_low and m_text_high fields.  */
 354
 355   unsigned int text_low_valid : 1;
 356   unsigned int text_high_valid : 1;
 357 };
 358
 359 /* A partial symtab that tracks the "readin" and "compunit_symtab"
 360    information in the ordinary way -- by storing it directly in this
 361    object.  */
 362 struct standard_psymtab : public partial_symtab
 363 {
 364   standard_psymtab (const char *filename, struct objfile *objfile)
 365     : partial_symtab (filename, objfile)
 366   {
 367   }
 368
 369   standard_psymtab (const char *filename, struct objfile *objfile,
 370                     CORE_ADDR addr)
 371     : partial_symtab (filename, objfile, addr)
 372   {
 373   }
 374
 375   bool readin_p (struct objfile *) const override
 376   {
 377     return readin;
 378   }
 379
 380   struct compunit_symtab *get_compunit_symtab (struct objfile *) const override
 381   {
 382     return compunit_symtab;
 383   }
 384
 385   /* True if the symtab corresponding to this psymtab has been
 386      readin.  */
 387
 388   bool readin = false;
 389
 390   /* Pointer to compunit eventually allocated for this source file, 0 if
 391      !readin or if we haven't looked for the symtab after it was readin.  */
 392
 393   struct compunit_symtab *compunit_symtab = nullptr;
 394 };
 395
 396 /* A partial_symtab that works in the historical db way.  This should
 397    not be used in new code, but exists to transition the somewhat
 398    unmaintained "legacy" debug formats.  */
 399
 400 struct legacy_psymtab : public standard_psymtab
 401 {
 402   legacy_psymtab (const char *filename, struct objfile *objfile)
 403     : standard_psymtab (filename, objfile)
 404   {
 405   }
 406
 407   legacy_psymtab (const char *filename, struct objfile *objfile,
 408                   CORE_ADDR addr)
 409     : standard_psymtab (filename, objfile, addr)
 410   {
 411   }
 412
 413   void read_symtab (struct objfile *objf) override
 414   {
 415     if (legacy_read_symtab)
 416       (*legacy_read_symtab) (this, objf);
 417   }
 418
 419   void expand_psymtab (struct objfile *objf) override
 420   {
 421     (*legacy_expand_psymtab) (this, objf);
 422   }
 423
 424   /* Pointer to function which will read in the symtab corresponding to
 425      this psymtab.  */
 426
 427   void (*legacy_read_symtab) (legacy_psymtab *, struct objfile *) = nullptr;
 428
 429   /* Pointer to function which will actually expand this psymtab into
 430      a full symtab.  */
 431
 432   void (*legacy_expand_psymtab) (legacy_psymtab *, struct objfile *) = nullptr;
 433
 434   /* Information that lets read_symtab() locate the part of the symbol table
 435      that this psymtab corresponds to.  This information is private to the
 436      format-dependent symbol reading routines.  For further detail examine
 437      the various symbol reading modules.  */
 438
 439   void *read_symtab_private = nullptr;
 440 };
 441
 442 /* Used when recording partial symbol tables.  On destruction,
 443    discards any partial symbol tables that have been built.  However,
 444    the tables can be kept by calling the "keep" method.  */
 445 class psymtab_discarder
 446 {
 447  public:
 448
 449   psymtab_discarder (struct objfile *objfile)
 450     : m_objfile (objfile),
 451       m_psymtab (objfile->partial_symtabs->psymtabs)
 452   {
 453   }
 454
 455   ~psymtab_discarder ()
 456   {
 457     if (m_objfile != NULL)
 458       m_objfile->partial_symtabs->discard_psymtabs_to (m_psymtab);
 459   }
 460
 461   /* Keep any partial symbol tables that were built.  */
 462   void keep ()
 463   {
 464     m_objfile = NULL;
 465   }
 466
 467  private:
 468
 469   /* The objfile.  If NULL this serves as a sentinel to indicate that
 470      the psymtabs should be kept.  */
 471   struct objfile *m_objfile;
 472   /* How far back to free.  */
 473   struct partial_symtab *m_psymtab;
 474 };
 475
 476 #endif /* PSYMPRIV_H */