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