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   /* Psymtab expansion is done in two steps:
 128      - a call to read_symtab
 129      - while that call is in progress, calls to expand_psymtab can be made,
 130        both for this psymtab, and its dependencies.
 131      This makes a distinction between a toplevel psymtab (for which both
 132      read_symtab and expand_psymtab will be called) and a non-toplevel
 133      psymtab (for which only expand_psymtab will be called). The
 134      distinction can be used f.i. to do things before and after all
 135      dependencies of a top-level psymtab have been expanded.
 136
 137      Read the full symbol table corresponding to this partial symbol
 138      table.  Typically calls expand_psymtab.  */
 139   virtual void read_symtab (struct objfile *) = 0;
 140
 141   /* Expand the full symbol table for this partial symbol table.  Typically
 142      calls expand_dependencies.  */
 143   virtual void expand_psymtab (struct objfile *) = 0;
 144
 145   /* Ensure that all the dependencies are read in.  Calls
 146      expand_psymtab for each non-shared dependency.  */
 147   void expand_dependencies (struct objfile *);
 148
 149   /* Return true if the symtab corresponding to this psymtab has been
 150      read in in the context of this objfile.  */
 151   virtual bool readin_p (struct objfile *) const = 0;
 152
 153   /* Return a pointer to the compunit allocated for this source file
 154      in the context of this objfile.
 155
 156      Return nullptr if the compunit was not read in or if there was no
 157      symtab.  */
 158   virtual struct compunit_symtab *get_compunit_symtab
 159     (struct objfile *) const = 0;
 160
 161   /* Return the raw low text address of this partial_symtab.  */
 162   CORE_ADDR raw_text_low () const
 163   {
 164     return m_text_low;
 165   }
 166
 167   /* Return the raw high text address of this partial_symtab.  */
 168   CORE_ADDR raw_text_high () const
 169   {
 170     return m_text_high;
 171   }
 172
 173   /* Return the relocated low text address of this partial_symtab.  */
 174   CORE_ADDR text_low (struct objfile *objfile) const
 175   {
 176     return m_text_low + objfile->text_section_offset ();
 177   }
 178
 179   /* Return the relocated high text address of this partial_symtab.  */
 180   CORE_ADDR text_high (struct objfile *objfile) const
 181   {
 182     return m_text_high + objfile->text_section_offset ();
 183   }
 184
 185   /* Set the low text address of this partial_symtab.  */
 186   void set_text_low (CORE_ADDR addr)
 187   {
 188     m_text_low = addr;
 189     text_low_valid = 1;
 190   }
 191
 192   /* Set the hight text address of this partial_symtab.  */
 193   void set_text_high (CORE_ADDR addr)
 194   {
 195     m_text_high = addr;
 196     text_high_valid = 1;
 197   }
 198
 199
 200   /* Chain of all existing partial symtabs.  */
 201
 202   struct partial_symtab *next = nullptr;
 203
 204   /* Name of the source file which this partial_symtab defines,
 205      or if the psymtab is anonymous then a descriptive name for
 206      debugging purposes, or "".  It must not be NULL.  */
 207
 208   const char *filename = nullptr;
 209
 210   /* Full path of the source file.  NULL if not known.  */
 211
 212   char *fullname = nullptr;
 213
 214   /* Directory in which it was compiled, or NULL if we don't know.  */
 215
 216   const char *dirname = nullptr;
 217
 218   /* Range of text addresses covered by this file; texthigh is the
 219      beginning of the next section.  Do not use if PSYMTABS_ADDRMAP_SUPPORTED
 220      is set.  Do not refer directly to these fields.  Instead, use the
 221      accessors.  The validity of these fields is determined by the
 222      text_low_valid and text_high_valid fields; these are located later
 223      in this structure for better packing.  */
 224
 225   CORE_ADDR m_text_low = 0;
 226   CORE_ADDR m_text_high = 0;
 227
 228   /* If NULL, this is an ordinary partial symbol table.
 229
 230      If non-NULL, this holds a single includer of this partial symbol
 231      table, and this partial symbol table is a shared one.
 232
 233      A shared psymtab is one that is referenced by multiple other
 234      psymtabs, and which conceptually has its contents directly
 235      included in those.
 236
 237      Shared psymtabs have special semantics.  When a search finds a
 238      symbol in a shared table, we instead return one of the non-shared
 239      tables that include this one.
 240
 241      A shared psymtabs can be referred to by other shared ones.
 242
 243      The psymtabs that refer to a shared psymtab will list the shared
 244      psymtab in their 'dependencies' array.
 245
 246      In DWARF terms, a shared psymtab is a DW_TAG_partial_unit; but
 247      of course using a name based on that would be too confusing, so
 248      "shared" was chosen instead.
 249
 250      Only a single user is needed because, when expanding a shared
 251      psymtab, we only need to expand its "canonical" non-shared user.
 252      The choice of which one should be canonical is left to the
 253      debuginfo reader; it can be arbitrary.  */
 254
 255   struct partial_symtab *user = nullptr;
 256
 257   /* Array of pointers to all of the partial_symtab's which this one
 258      depends on.  Since this array can only be set to previous or
 259      the current (?) psymtab, this dependency tree is guaranteed not
 260      to have any loops.  "depends on" means that symbols must be read
 261      for the dependencies before being read for this psymtab; this is
 262      for type references in stabs, where if foo.c includes foo.h, declarations
 263      in foo.h may use type numbers defined in foo.c.  For other debugging
 264      formats there may be no need to use dependencies.  */
 265
 266   struct partial_symtab **dependencies = nullptr;
 267
 268   int number_of_dependencies = 0;
 269
 270   /* Global symbol list.  This list will be sorted after readin to
 271      improve access.  Binary search will be the usual method of
 272      finding a symbol within it.  globals_offset is an integer offset
 273      within global_psymbols[].  */
 274
 275   int globals_offset = 0;
 276   int n_global_syms = 0;
 277
 278   /* Static symbol list.  This list will *not* be sorted after readin;
 279      to find a symbol in it, exhaustive search must be used.  This is
 280      reasonable because searches through this list will eventually
 281      lead to either the read in of a files symbols for real (assumed
 282      to take a *lot* of time; check) or an error (and we don't care
 283      how long errors take).  This is an offset and size within
 284      static_psymbols[].  */
 285
 286   int statics_offset = 0;
 287   int n_static_syms = 0;
 288
 289   /* True iff objfile->psymtabs_addrmap is properly populated for this
 290      partial_symtab.  For discontiguous overlapping psymtabs is the only usable
 291      info in PSYMTABS_ADDRMAP.  */
 292
 293   bool psymtabs_addrmap_supported = false;
 294
 295   /* True if the name of this partial symtab is not a source file name.  */
 296
 297   bool anonymous = false;
 298
 299   /* A flag that is temporarily used when searching psymtabs.  */
 300
 301   ENUM_BITFIELD (psymtab_search_status) searched_flag : 2;
 302
 303   /* Validity of the m_text_low and m_text_high fields.  */
 304
 305   unsigned int text_low_valid : 1;
 306   unsigned int text_high_valid : 1;
 307 };
 308
 309 /* A partial symtab that tracks the "readin" and "compunit_symtab"
 310    information in the ordinary way -- by storing it directly in this
 311    object.  */
 312 struct standard_psymtab : public partial_symtab
 313 {
 314   standard_psymtab (const char *filename, struct objfile *objfile)
 315     : partial_symtab (filename, objfile)
 316   {
 317   }
 318
 319   standard_psymtab (const char *filename, struct objfile *objfile,
 320                     CORE_ADDR addr)
 321     : partial_symtab (filename, objfile, addr)
 322   {
 323   }
 324
 325   bool readin_p (struct objfile *) const override
 326   {
 327     return readin;
 328   }
 329
 330   struct compunit_symtab *get_compunit_symtab (struct objfile *) const override
 331   {
 332     return compunit_symtab;
 333   }
 334
 335   /* True if the symtab corresponding to this psymtab has been
 336      readin.  */
 337
 338   bool readin = false;
 339
 340   /* Pointer to compunit eventually allocated for this source file, 0 if
 341      !readin or if we haven't looked for the symtab after it was readin.  */
 342
 343   struct compunit_symtab *compunit_symtab = nullptr;
 344 };
 345
 346 /* A partial_symtab that works in the historical db way.  This should
 347    not be used in new code, but exists to transition the somewhat
 348    unmaintained "legacy" debug formats.  */
 349
 350 struct legacy_psymtab : public standard_psymtab
 351 {
 352   legacy_psymtab (const char *filename, struct objfile *objfile)
 353     : standard_psymtab (filename, objfile)
 354   {
 355   }
 356
 357   legacy_psymtab (const char *filename, struct objfile *objfile,
 358                   CORE_ADDR addr)
 359     : standard_psymtab (filename, objfile, addr)
 360   {
 361   }
 362
 363   void read_symtab (struct objfile *objf) override
 364   {
 365     if (legacy_read_symtab)
 366       (*legacy_read_symtab) (this, objf);
 367   }
 368
 369   void expand_psymtab (struct objfile *objf) override
 370   {
 371     (*legacy_expand_psymtab) (this, objf);
 372   }
 373
 374   /* Pointer to function which will read in the symtab corresponding to
 375      this psymtab.  */
 376
 377   void (*legacy_read_symtab) (legacy_psymtab *, struct objfile *) = nullptr;
 378
 379   /* Pointer to function which will actually expand this psymtab into
 380      a full symtab.  */
 381
 382   void (*legacy_expand_psymtab) (legacy_psymtab *, struct objfile *) = nullptr;
 383
 384   /* Information that lets read_symtab() locate the part of the symbol table
 385      that this psymtab corresponds to.  This information is private to the
 386      format-dependent symbol reading routines.  For further detail examine
 387      the various symbol reading modules.  */
 388
 389   void *read_symtab_private = nullptr;
 390 };
 391
 392 /* Specify whether a partial psymbol should be allocated on the global
 393    list or the static list.  */
 394
 395 enum class psymbol_placement
 396 {
 397   STATIC,
 398   GLOBAL
 399 };
 400
 401 /* Add a symbol to the partial symbol table of OBJFILE.
 402
 403    If COPY_NAME is true, make a copy of NAME, otherwise use the passed
 404    reference.
 405
 406    THECLASS is the type of symbol.
 407
 408    SECTION is the index of the section of OBJFILE in which the symbol is found.
 409
 410    WHERE determines whether the symbol goes in the list of static or global
 411    partial symbols of OBJFILE.
 412
 413    COREADDR is the address of the symbol.  For partial symbols that don't have
 414    an address, zero is passed.
 415
 416    LANGUAGE is the language from which the symbol originates.  This will
 417    influence, amongst other things, how the symbol name is demangled. */
 418
 419 extern void add_psymbol_to_list (gdb::string_view name,
 420                                  bool copy_name, domain_enum domain,
 421                                  enum address_class theclass,
 422                                  short section,
 423                                  psymbol_placement where,
 424                                  CORE_ADDR coreaddr,
 425                                  enum language language,
 426                                  struct objfile *objfile);
 427
 428 /* Add a symbol to the partial symbol table of OBJFILE.  The psymbol
 429    must be fully constructed, and the names must be set and intern'd
 430    as appropriate.  */
 431
 432 extern void add_psymbol_to_list (const partial_symbol &psym,
 433                                  psymbol_placement where,
 434                                  struct objfile *objfile);
 435
 436 /* Initialize storage for partial symbols.  If partial symbol storage
 437    has already been initialized, this does nothing.  TOTAL_SYMBOLS is
 438    an estimate of how many symbols there will be.  */
 439
 440 extern void init_psymbol_list (struct objfile *objfile, int total_symbols);
 441
 442 extern void end_psymtab_common (struct objfile *, struct partial_symtab *);
 443
 444 /* Used when recording partial symbol tables.  On destruction,
 445    discards any partial symbol tables that have been built.  However,
 446    the tables can be kept by calling the "keep" method.  */
 447 class psymtab_discarder
 448 {
 449  public:
 450
 451   psymtab_discarder (struct objfile *objfile)
 452     : m_objfile (objfile),
 453       m_psymtab (objfile->partial_symtabs->psymtabs)
 454   {
 455   }
 456
 457   ~psymtab_discarder ()
 458   {
 459     if (m_objfile != NULL)
 460       m_objfile->partial_symtabs->discard_psymtabs_to (m_psymtab);
 461   }
 462
 463   /* Keep any partial symbol tables that were built.  */
 464   void keep ()
 465   {
 466     m_objfile = NULL;
 467   }
 468
 469  private:
 470
 471   /* The objfile.  If NULL this serves as a sentinel to indicate that
 472      the psymtabs should be kept.  */
 473   struct objfile *m_objfile;
 474   /* How far back to free.  */
 475   struct partial_symtab *m_psymtab;
 476 };
 477
 478 #endif /* PSYMPRIV_H */