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