gdb/psympriv.h

   1 /* Private partial symbol table definitions.
   2
   3    Copyright (C) 2009-2020 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     if (ginfo.section >= 0)
  44       return &objfile->sections[ginfo.section];
  45     return nullptr;
  46   }
  47
  48   /* Return the unrelocated address of this partial symbol.  */
  49   CORE_ADDR unrelocated_address () const
  50   {
  51     return ginfo.value.address;
  52   }
  53
  54   /* Return the address of this partial symbol, relocated according to
  55      the offsets provided in OBJFILE.  */
  56   CORE_ADDR address (const struct objfile *objfile) const
  57   {
  58     return ginfo.value.address + objfile->section_offsets[ginfo.section];
  59   }
  60
  61   /* Set the address of this partial symbol.  The address must be
  62      unrelocated.  */
  63   void set_unrelocated_address (CORE_ADDR addr)
  64   {
  65     ginfo.value.address = addr;
  66   }
  67
  68   /* Note that partial_symbol does not derive from general_symbol_info
  69      due to the bcache.  See add_psymbol_to_bcache.  */
  70
  71   struct general_symbol_info ginfo;
  72
  73   /* Name space code.  */
  74
  75   ENUM_BITFIELD(domain_enum_tag) domain : SYMBOL_DOMAIN_BITS;
  76
  77   /* Address class (for info_symbols).  Note that we don't allow
  78      synthetic "aclass" values here at present, simply because there's
  79      no need.  */
  80
  81   ENUM_BITFIELD(address_class) aclass : SYMBOL_ACLASS_BITS;
  82 };
  83
  84 /* A convenience enum to give names to some constants used when
  85    searching psymtabs.  This is internal to psymtab and should not be
  86    used elsewhere.  */
  87
  88 enum psymtab_search_status
  89   {
  90     PST_NOT_SEARCHED,
  91     PST_SEARCHED_AND_FOUND,
  92     PST_SEARCHED_AND_NOT_FOUND
  93   };
  94
  95 /* Each source file that has not been fully read in is represented by
  96    a partial_symtab.  This contains the information on where in the
  97    executable the debugging symbols for a specific file are, and a
  98    list of names of global symbols which are located in this file.
  99    They are all chained on partial symtab lists.
 100
 101    Even after the source file has been read into a symtab, the
 102    partial_symtab remains around.  */
 103
 104 struct partial_symtab
 105 {
 106   /* Allocate a new partial symbol table associated with OBJFILE.
 107      FILENAME (which must be non-NULL) is the filename of this partial
 108      symbol table; it is copied into the appropriate storage.  The
 109      partial symtab will also be installed using
 110      psymtab_storage::install.  */
 111
 112   partial_symtab (const char *filename, struct objfile *objfile)
 113     ATTRIBUTE_NONNULL (2) ATTRIBUTE_NONNULL (3);
 114
 115   /* Like the above, but also sets the initial text low and text high
 116      from the ADDR argument, and sets the global- and
 117      static-offsets.  */
 118
 119   partial_symtab (const char *filename, struct objfile *objfile,
 120                   CORE_ADDR addr)
 121     ATTRIBUTE_NONNULL (2) ATTRIBUTE_NONNULL (3);
 122
 123   virtual ~partial_symtab ()
 124   {
 125   }
 126
 127   /* Read the full symbol table corresponding to this partial symbol
 128      table.  */
 129   virtual void read_symtab (struct objfile *) = 0;
 130
 131   /* Psymtab expansion is done in two steps.  The first step is a call
 132      to read_symtab; but while that is in progress, calls to
 133      expand_psymtab can be made.  */
 134   virtual void expand_psymtab (struct objfile *) = 0;
 135
 136   /* Ensure that all the dependencies are read in.  */
 137   void read_dependencies (struct objfile *);
 138
 139   /* Return true if the symtab corresponding to this psymtab has been
 140      readin.  */
 141   virtual bool readin_p () const = 0;
 142
 143   /* Return a pointer to the compunit allocated for this source file.
 144      Return nullptr if !readin or if there was no symtab.  */
 145   virtual struct compunit_symtab *get_compunit_symtab () const = 0;
 146
 147
 148   /* Return the raw low text address of this partial_symtab.  */
 149   CORE_ADDR raw_text_low () const
 150   {
 151     return m_text_low;
 152   }
 153
 154   /* Return the raw high text address of this partial_symtab.  */
 155   CORE_ADDR raw_text_high () const
 156   {
 157     return m_text_high;
 158   }
 159
 160   /* Return the relocated low text address of this partial_symtab.  */
 161   CORE_ADDR text_low (struct objfile *objfile) const
 162   {
 163     return m_text_low + objfile->text_section_offset ();
 164   }
 165
 166   /* Return the relocated high text address of this partial_symtab.  */
 167   CORE_ADDR text_high (struct objfile *objfile) const
 168   {
 169     return m_text_high + objfile->text_section_offset ();
 170   }
 171
 172   /* Set the low text address of this partial_symtab.  */
 173   void set_text_low (CORE_ADDR addr)
 174   {
 175     m_text_low = addr;
 176     text_low_valid = 1;
 177   }
 178
 179   /* Set the hight text address of this partial_symtab.  */
 180   void set_text_high (CORE_ADDR addr)
 181   {
 182     m_text_high = addr;
 183     text_high_valid = 1;
 184   }
 185
 186
 187   /* Chain of all existing partial symtabs.  */
 188
 189   struct partial_symtab *next = nullptr;
 190
 191   /* Name of the source file which this partial_symtab defines,
 192      or if the psymtab is anonymous then a descriptive name for
 193      debugging purposes, or "".  It must not be NULL.  */
 194
 195   const char *filename = nullptr;
 196
 197   /* Full path of the source file.  NULL if not known.  */
 198
 199   char *fullname = nullptr;
 200
 201   /* Directory in which it was compiled, or NULL if we don't know.  */
 202
 203   const char *dirname = nullptr;
 204
 205   /* Range of text addresses covered by this file; texthigh is the
 206      beginning of the next section.  Do not use if PSYMTABS_ADDRMAP_SUPPORTED
 207      is set.  Do not refer directly to these fields.  Instead, use the
 208      accessors.  The validity of these fields is determined by the
 209      text_low_valid and text_high_valid fields; these are located later
 210      in this structure for better packing.  */
 211
 212   CORE_ADDR m_text_low = 0;
 213   CORE_ADDR m_text_high = 0;
 214
 215   /* If NULL, this is an ordinary partial symbol table.
 216
 217      If non-NULL, this holds a single includer of this partial symbol
 218      table, and this partial symbol table is a shared one.
 219
 220      A shared psymtab is one that is referenced by multiple other
 221      psymtabs, and which conceptually has its contents directly
 222      included in those.
 223
 224      Shared psymtabs have special semantics.  When a search finds a
 225      symbol in a shared table, we instead return one of the non-shared
 226      tables that include this one.
 227
 228      A shared psymtabs can be referred to by other shared ones.
 229
 230      The psymtabs that refer to a shared psymtab will list the shared
 231      psymtab in their 'dependencies' array.
 232
 233      In DWARF terms, a shared psymtab is a DW_TAG_partial_unit; but
 234      of course using a name based on that would be too confusing, so
 235      "shared" was chosen instead.
 236
 237      Only a single user is needed because, when expanding a shared
 238      psymtab, we only need to expand its "canonical" non-shared user.
 239      The choice of which one should be canonical is left to the
 240      debuginfo reader; it can be arbitrary.  */
 241
 242   struct partial_symtab *user = nullptr;
 243
 244   /* Array of pointers to all of the partial_symtab's which this one
 245      depends on.  Since this array can only be set to previous or
 246      the current (?) psymtab, this dependency tree is guaranteed not
 247      to have any loops.  "depends on" means that symbols must be read
 248      for the dependencies before being read for this psymtab; this is
 249      for type references in stabs, where if foo.c includes foo.h, declarations
 250      in foo.h may use type numbers defined in foo.c.  For other debugging
 251      formats there may be no need to use dependencies.  */
 252
 253   struct partial_symtab **dependencies = nullptr;
 254
 255   int number_of_dependencies = 0;
 256
 257   /* Global symbol list.  This list will be sorted after readin to
 258      improve access.  Binary search will be the usual method of
 259      finding a symbol within it.  globals_offset is an integer offset
 260      within global_psymbols[].  */
 261
 262   int globals_offset = 0;
 263   int n_global_syms = 0;
 264
 265   /* Static symbol list.  This list will *not* be sorted after readin;
 266      to find a symbol in it, exhaustive search must be used.  This is
 267      reasonable because searches through this list will eventually
 268      lead to either the read in of a files symbols for real (assumed
 269      to take a *lot* of time; check) or an error (and we don't care
 270      how long errors take).  This is an offset and size within
 271      static_psymbols[].  */
 272
 273   int statics_offset = 0;
 274   int n_static_syms = 0;
 275
 276   /* True iff objfile->psymtabs_addrmap is properly populated for this
 277      partial_symtab.  For discontiguous overlapping psymtabs is the only usable
 278      info in PSYMTABS_ADDRMAP.  */
 279
 280   bool psymtabs_addrmap_supported = false;
 281
 282   /* True if the name of this partial symtab is not a source file name.  */
 283
 284   bool anonymous = false;
 285
 286   /* A flag that is temporarily used when searching psymtabs.  */
 287
 288   ENUM_BITFIELD (psymtab_search_status) searched_flag : 2;
 289
 290   /* Validity of the m_text_low and m_text_high fields.  */
 291
 292   unsigned int text_low_valid : 1;
 293   unsigned int text_high_valid : 1;
 294 };
 295
 296 /* A partial symtab that tracks the "readin" and "compunit_symtab"
 297    information in the ordinary way -- by storing it directly in this
 298    object.  */
 299 struct standard_psymtab : public partial_symtab
 300 {
 301   standard_psymtab (const char *filename, struct objfile *objfile)
 302     : partial_symtab (filename, objfile)
 303   {
 304   }
 305
 306   standard_psymtab (const char *filename, struct objfile *objfile,
 307                     CORE_ADDR addr)
 308     : partial_symtab (filename, objfile, addr)
 309   {
 310   }
 311
 312   bool readin_p () const override
 313   {
 314     return readin;
 315   }
 316
 317   /* Return a pointer to the compunit allocated for this source file.
 318      Return nullptr if !readin or if there was no symtab.  */
 319   struct compunit_symtab *get_compunit_symtab () const override
 320   {
 321     return compunit_symtab;
 322   }
 323
 324   /* True if the symtab corresponding to this psymtab has been
 325      readin.  */
 326
 327   bool readin = false;
 328
 329   /* Pointer to compunit eventually allocated for this source file, 0 if
 330      !readin or if we haven't looked for the symtab after it was readin.  */
 331
 332   struct compunit_symtab *compunit_symtab = nullptr;
 333 };
 334
 335 /* A partial_symtab that works in the historical db way.  This should
 336    not be used in new code, but exists to transition the somewhat
 337    unmaintained "legacy" debug formats.  */
 338
 339 struct legacy_psymtab : public standard_psymtab
 340 {
 341   legacy_psymtab (const char *filename, struct objfile *objfile)
 342     : standard_psymtab (filename, objfile)
 343   {
 344   }
 345
 346   legacy_psymtab (const char *filename, struct objfile *objfile,
 347                   CORE_ADDR addr)
 348     : standard_psymtab (filename, objfile, addr)
 349   {
 350   }
 351
 352   void read_symtab (struct objfile *objf) override
 353   {
 354     if (legacy_read_symtab)
 355       (*legacy_read_symtab) (this, objf);
 356   }
 357
 358   void expand_psymtab (struct objfile *objf) override
 359   {
 360     (*legacy_expand_psymtab) (this, objf);
 361   }
 362
 363   /* Pointer to function which will read in the symtab corresponding to
 364      this psymtab.  */
 365
 366   void (*legacy_read_symtab) (legacy_psymtab *, struct objfile *) = nullptr;
 367
 368   /* Pointer to function which will actually expand this psymtab into
 369      a full symtab.  */
 370
 371   void (*legacy_expand_psymtab) (legacy_psymtab *, struct objfile *) = nullptr;
 372
 373   /* Information that lets read_symtab() locate the part of the symbol table
 374      that this psymtab corresponds to.  This information is private to the
 375      format-dependent symbol reading routines.  For further detail examine
 376      the various symbol reading modules.  */
 377
 378   void *read_symtab_private = nullptr;
 379 };
 380
 381 /* Specify whether a partial psymbol should be allocated on the global
 382    list or the static list.  */
 383
 384 enum class psymbol_placement
 385 {
 386   STATIC,
 387   GLOBAL
 388 };
 389
 390 /* Add a symbol to the partial symbol table of OBJFILE.
 391
 392    If COPY_NAME is true, make a copy of NAME, otherwise use the passed
 393    reference.
 394
 395    THECLASS is the type of symbol.
 396
 397    SECTION is the index of the section of OBJFILE in which the symbol is found.
 398
 399    WHERE determines whether the symbol goes in the list of static or global
 400    partial symbols of OBJFILE.
 401
 402    COREADDR is the address of the symbol.  For partial symbols that don't have
 403    an address, zero is passed.
 404
 405    LANGUAGE is the language from which the symbol originates.  This will
 406    influence, amongst other things, how the symbol name is demangled. */
 407
 408 extern void add_psymbol_to_list (gdb::string_view name,
 409                                  bool copy_name, domain_enum domain,
 410                                  enum address_class theclass,
 411                                  short section,
 412                                  psymbol_placement where,
 413                                  CORE_ADDR coreaddr,
 414                                  enum language language,
 415                                  struct objfile *objfile);
 416
 417 /* Initialize storage for partial symbols.  If partial symbol storage
 418    has already been initialized, this does nothing.  TOTAL_SYMBOLS is
 419    an estimate of how many symbols there will be.  */
 420
 421 extern void init_psymbol_list (struct objfile *objfile, int total_symbols);
 422
 423 extern void end_psymtab_common (struct objfile *, struct partial_symtab *);
 424
 425 static inline void
 426 discard_psymtab (struct objfile *objfile, struct partial_symtab *pst)
 427 {
 428   objfile->partial_symtabs->discard_psymtab (pst);
 429 }
 430
 431 /* Used when recording partial symbol tables.  On destruction,
 432    discards any partial symbol tables that have been built.  However,
 433    the tables can be kept by calling the "keep" method.  */
 434 class psymtab_discarder
 435 {
 436  public:
 437
 438   psymtab_discarder (struct objfile *objfile)
 439     : m_objfile (objfile),
 440       m_psymtab (objfile->partial_symtabs->psymtabs)
 441   {
 442   }
 443
 444   ~psymtab_discarder ()
 445   {
 446     if (m_objfile != NULL)
 447       m_objfile->partial_symtabs->discard_psymtabs_to (m_psymtab);
 448   }
 449
 450   /* Keep any partial symbol tables that were built.  */
 451   void keep ()
 452   {
 453     m_objfile = NULL;
 454   }
 455
 456  private:
 457
 458   /* The objfile.  If NULL this serves as a sentinel to indicate that
 459      the psymtabs should be kept.  */
 460   struct objfile *m_objfile;
 461   /* How far back to free.  */
 462   struct partial_symtab *m_psymtab;
 463 };
 464
 465 #endif /* PSYMPRIV_H */