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 /* Specify whether a partial psymbol should be allocated on the global
  96    list or the static list.  */
  97
  98 enum class psymbol_placement
  99 {
 100   STATIC,
 101   GLOBAL
 102 };
 103
 104 /* Each source file that has not been fully read in is represented by
 105    a partial_symtab.  This contains the information on where in the
 106    executable the debugging symbols for a specific file are, and a
 107    list of names of global symbols which are located in this file.
 108    They are all chained on partial symtab lists.
 109
 110    Even after the source file has been read into a symtab, the
 111    partial_symtab remains around.  */
 112
 113 struct partial_symtab
 114 {
 115   /* Allocate a new partial symbol table associated with OBJFILE.
 116      FILENAME (which must be non-NULL) is the filename of this partial
 117      symbol table; it is copied into the appropriate storage.  The
 118      partial symtab will also be installed using
 119      psymtab_storage::install.  */
 120
 121   partial_symtab (const char *filename, struct objfile *objfile)
 122     ATTRIBUTE_NONNULL (2) ATTRIBUTE_NONNULL (3);
 123
 124   /* Like the above, but also sets the initial text low and text high
 125      from the ADDR argument, and sets the global- and
 126      static-offsets.  */
 127
 128   partial_symtab (const char *filename, struct objfile *objfile,
 129                   CORE_ADDR addr)
 130     ATTRIBUTE_NONNULL (2) ATTRIBUTE_NONNULL (3);
 131
 132   virtual ~partial_symtab ()
 133   {
 134   }
 135
 136   /* Psymtab expansion is done in two steps:
 137      - a call to read_symtab
 138      - while that call is in progress, calls to expand_psymtab can be made,
 139        both for this psymtab, and its dependencies.
 140      This makes a distinction between a toplevel psymtab (for which both
 141      read_symtab and expand_psymtab will be called) and a non-toplevel
 142      psymtab (for which only expand_psymtab will be called). The
 143      distinction can be used f.i. to do things before and after all
 144      dependencies of a top-level psymtab have been expanded.
 145
 146      Read the full symbol table corresponding to this partial symbol
 147      table.  Typically calls expand_psymtab.  */
 148   virtual void read_symtab (struct objfile *) = 0;
 149
 150   /* Expand the full symbol table for this partial symbol table.  Typically
 151      calls expand_dependencies.  */
 152   virtual void expand_psymtab (struct objfile *) = 0;
 153
 154   /* Ensure that all the dependencies are read in.  Calls
 155      expand_psymtab for each non-shared dependency.  */
 156   void expand_dependencies (struct objfile *);
 157
 158   /* Return true if the symtab corresponding to this psymtab has been
 159      read in in the context of this objfile.  */
 160   virtual bool readin_p (struct objfile *) const = 0;
 161
 162   /* Return a pointer to the compunit allocated for this source file
 163      in the context of this objfile.
 164
 165      Return nullptr if the compunit was not read in or if there was no
 166      symtab.  */
 167   virtual struct compunit_symtab *get_compunit_symtab
 168     (struct objfile *) const = 0;
 169
 170   /* Return the raw low text address of this partial_symtab.  */
 171   CORE_ADDR raw_text_low () const
 172   {
 173     return m_text_low;
 174   }
 175
 176   /* Return the raw high text address of this partial_symtab.  */
 177   CORE_ADDR raw_text_high () const
 178   {
 179     return m_text_high;
 180   }
 181
 182   /* Return the relocated low text address of this partial_symtab.  */
 183   CORE_ADDR text_low (struct objfile *objfile) const
 184   {
 185     return m_text_low + objfile->text_section_offset ();
 186   }
 187
 188   /* Return the relocated high text address of this partial_symtab.  */
 189   CORE_ADDR text_high (struct objfile *objfile) const
 190   {
 191     return m_text_high + objfile->text_section_offset ();
 192   }
 193
 194   /* Set the low text address of this partial_symtab.  */
 195   void set_text_low (CORE_ADDR addr)
 196   {
 197     m_text_low = addr;
 198     text_low_valid = 1;
 199   }
 200
 201   /* Set the hight text address of this partial_symtab.  */
 202   void set_text_high (CORE_ADDR addr)
 203   {
 204     m_text_high = addr;
 205     text_high_valid = 1;
 206   }
 207
 208   /* Return true if this symtab is empty -- meaning that it contains
 209      no symbols.  It may still have dependencies.  */
 210   bool empty () const
 211   {
 212     return global_psymbols.empty () && static_psymbols.empty ();
 213   }
 214
 215   /* Add a symbol to this partial symbol table of OBJFILE.
 216
 217      If COPY_NAME is true, make a copy of NAME, otherwise use the passed
 218      reference.
 219
 220      THECLASS is the type of symbol.
 221
 222      SECTION is the index of the section of OBJFILE in which the symbol is found.
 223
 224      WHERE determines whether the symbol goes in the list of static or global
 225      partial symbols.
 226
 227      COREADDR is the address of the symbol.  For partial symbols that don't have
 228      an address, zero is passed.
 229
 230      LANGUAGE is the language from which the symbol originates.  This will
 231      influence, amongst other things, how the symbol name is demangled. */
 232
 233   void add_psymbol (gdb::string_view name,
 234                     bool copy_name, domain_enum domain,
 235                     enum address_class theclass,
 236                     short section,
 237                     psymbol_placement where,
 238                     CORE_ADDR coreaddr,
 239                     enum language language,
 240                     struct objfile *objfile);
 241
 242   /* Add a symbol to this partial symbol table of OBJFILE.  The psymbol
 243      must be fully constructed, and the names must be set and intern'd
 244      as appropriate.  */
 245
 246   void add_psymbol (const partial_symbol &psym,
 247                     psymbol_placement where,
 248                     struct objfile *objfile);
 249
 250
 251   /* Chain of all existing partial symtabs.  */
 252
 253   struct partial_symtab *next = nullptr;
 254
 255   /* Name of the source file which this partial_symtab defines,
 256      or if the psymtab is anonymous then a descriptive name for
 257      debugging purposes, or "".  It must not be NULL.  */
 258
 259   const char *filename = nullptr;
 260
 261   /* Full path of the source file.  NULL if not known.  */
 262
 263   char *fullname = nullptr;
 264
 265   /* Directory in which it was compiled, or NULL if we don't know.  */
 266
 267   const char *dirname = nullptr;
 268
 269   /* Range of text addresses covered by this file; texthigh is the
 270      beginning of the next section.  Do not use if PSYMTABS_ADDRMAP_SUPPORTED
 271      is set.  Do not refer directly to these fields.  Instead, use the
 272      accessors.  The validity of these fields is determined by the
 273      text_low_valid and text_high_valid fields; these are located later
 274      in this structure for better packing.  */
 275
 276   CORE_ADDR m_text_low = 0;
 277   CORE_ADDR m_text_high = 0;
 278
 279   /* If NULL, this is an ordinary partial symbol table.
 280
 281      If non-NULL, this holds a single includer of this partial symbol
 282      table, and this partial symbol table is a shared one.
 283
 284      A shared psymtab is one that is referenced by multiple other
 285      psymtabs, and which conceptually has its contents directly
 286      included in those.
 287
 288      Shared psymtabs have special semantics.  When a search finds a
 289      symbol in a shared table, we instead return one of the non-shared
 290      tables that include this one.
 291
 292      A shared psymtabs can be referred to by other shared ones.
 293
 294      The psymtabs that refer to a shared psymtab will list the shared
 295      psymtab in their 'dependencies' array.
 296
 297      In DWARF terms, a shared psymtab is a DW_TAG_partial_unit; but
 298      of course using a name based on that would be too confusing, so
 299      "shared" was chosen instead.
 300
 301      Only a single user is needed because, when expanding a shared
 302      psymtab, we only need to expand its "canonical" non-shared user.
 303      The choice of which one should be canonical is left to the
 304      debuginfo reader; it can be arbitrary.  */
 305
 306   struct partial_symtab *user = nullptr;
 307
 308   /* Array of pointers to all of the partial_symtab's which this one
 309      depends on.  Since this array can only be set to previous or
 310      the current (?) psymtab, this dependency tree is guaranteed not
 311      to have any loops.  "depends on" means that symbols must be read
 312      for the dependencies before being read for this psymtab; this is
 313      for type references in stabs, where if foo.c includes foo.h, declarations
 314      in foo.h may use type numbers defined in foo.c.  For other debugging
 315      formats there may be no need to use dependencies.  */
 316
 317   struct partial_symtab **dependencies = nullptr;
 318
 319   int number_of_dependencies = 0;
 320
 321   /* Global symbol list.  This list will be sorted after readin to
 322      improve access.  Binary search will be the usual method of
 323      finding a symbol within it.  */
 324
 325   std::vector<partial_symbol *> global_psymbols;
 326
 327   /* Static symbol list.  This list will *not* be sorted after readin;
 328      to find a symbol in it, exhaustive search must be used.  This is
 329      reasonable because searches through this list will eventually
 330      lead to either the read in of a files symbols for real (assumed
 331      to take a *lot* of time; check) or an error (and we don't care
 332      how long errors take).  */
 333
 334   std::vector<partial_symbol *> static_psymbols;
 335
 336   /* True iff objfile->psymtabs_addrmap is properly populated for this
 337      partial_symtab.  For discontiguous overlapping psymtabs is the only usable
 338      info in PSYMTABS_ADDRMAP.  */
 339
 340   bool psymtabs_addrmap_supported = false;
 341
 342   /* True if the name of this partial symtab is not a source file name.  */
 343
 344   bool anonymous = false;
 345
 346   /* A flag that is temporarily used when searching psymtabs.  */
 347
 348   ENUM_BITFIELD (psymtab_search_status) searched_flag : 2;
 349
 350   /* Validity of the m_text_low and m_text_high fields.  */
 351
 352   unsigned int text_low_valid : 1;
 353   unsigned int text_high_valid : 1;
 354 };
 355
 356 /* A partial symtab that tracks the "readin" and "compunit_symtab"
 357    information in the ordinary way -- by storing it directly in this
 358    object.  */
 359 struct standard_psymtab : public partial_symtab
 360 {
 361   standard_psymtab (const char *filename, struct objfile *objfile)
 362     : partial_symtab (filename, objfile)
 363   {
 364   }
 365
 366   standard_psymtab (const char *filename, struct objfile *objfile,
 367                     CORE_ADDR addr)
 368     : partial_symtab (filename, objfile, addr)
 369   {
 370   }
 371
 372   bool readin_p (struct objfile *) const override
 373   {
 374     return readin;
 375   }
 376
 377   struct compunit_symtab *get_compunit_symtab (struct objfile *) const override
 378   {
 379     return compunit_symtab;
 380   }
 381
 382   /* True if the symtab corresponding to this psymtab has been
 383      readin.  */
 384
 385   bool readin = false;
 386
 387   /* Pointer to compunit eventually allocated for this source file, 0 if
 388      !readin or if we haven't looked for the symtab after it was readin.  */
 389
 390   struct compunit_symtab *compunit_symtab = nullptr;
 391 };
 392
 393 /* A partial_symtab that works in the historical db way.  This should
 394    not be used in new code, but exists to transition the somewhat
 395    unmaintained "legacy" debug formats.  */
 396
 397 struct legacy_psymtab : public standard_psymtab
 398 {
 399   legacy_psymtab (const char *filename, struct objfile *objfile)
 400     : standard_psymtab (filename, objfile)
 401   {
 402   }
 403
 404   legacy_psymtab (const char *filename, struct objfile *objfile,
 405                   CORE_ADDR addr)
 406     : standard_psymtab (filename, objfile, addr)
 407   {
 408   }
 409
 410   void read_symtab (struct objfile *objf) override
 411   {
 412     if (legacy_read_symtab)
 413       (*legacy_read_symtab) (this, objf);
 414   }
 415
 416   void expand_psymtab (struct objfile *objf) override
 417   {
 418     (*legacy_expand_psymtab) (this, objf);
 419   }
 420
 421   /* Pointer to function which will read in the symtab corresponding to
 422      this psymtab.  */
 423
 424   void (*legacy_read_symtab) (legacy_psymtab *, struct objfile *) = nullptr;
 425
 426   /* Pointer to function which will actually expand this psymtab into
 427      a full symtab.  */
 428
 429   void (*legacy_expand_psymtab) (legacy_psymtab *, struct objfile *) = nullptr;
 430
 431   /* Information that lets read_symtab() locate the part of the symbol table
 432      that this psymtab corresponds to.  This information is private to the
 433      format-dependent symbol reading routines.  For further detail examine
 434      the various symbol reading modules.  */
 435
 436   void *read_symtab_private = nullptr;
 437 };
 438
 439 /* Initialize storage for partial symbols.  If partial symbol storage
 440    has already been initialized, this does nothing.  TOTAL_SYMBOLS is
 441    an estimate of how many symbols there will be.  */
 442
 443 extern void init_psymbol_list (struct objfile *objfile, int total_symbols);
 444
 445 extern void end_psymtab_common (struct objfile *, struct partial_symtab *);
 446
 447 /* Used when recording partial symbol tables.  On destruction,
 448    discards any partial symbol tables that have been built.  However,
 449    the tables can be kept by calling the "keep" method.  */
 450 class psymtab_discarder
 451 {
 452  public:
 453
 454   psymtab_discarder (struct objfile *objfile)
 455     : m_objfile (objfile),
 456       m_psymtab (objfile->partial_symtabs->psymtabs)
 457   {
 458   }
 459
 460   ~psymtab_discarder ()
 461   {
 462     if (m_objfile != NULL)
 463       m_objfile->partial_symtabs->discard_psymtabs_to (m_psymtab);
 464   }
 465
 466   /* Keep any partial symbol tables that were built.  */
 467   void keep ()
 468   {
 469     m_objfile = NULL;
 470   }
 471
 472  private:
 473
 474   /* The objfile.  If NULL this serves as a sentinel to indicate that
 475      the psymtabs should be kept.  */
 476   struct objfile *m_objfile;
 477   /* How far back to free.  */
 478   struct partial_symtab *m_psymtab;
 479 };
 480
 481 #endif /* PSYMPRIV_H */