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