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