gdb/psympriv.h

   1 /* Private partial symbol table definitions.
   2
   3    Copyright (C) 2009-2019 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
  59             + ANOFFSET (objfile->section_offsets, ginfo.section));
  60   }
  61
  62   /* Set the address of this partial symbol.  The address must be
  63      unrelocated.  */
  64   void set_unrelocated_address (CORE_ADDR addr)
  65   {
  66     ginfo.value.address = addr;
  67   }
  68
  69   /* Note that partial_symbol does not derive from general_symbol_info
  70      due to the bcache.  See add_psymbol_to_bcache.  */
  71
  72   struct general_symbol_info ginfo;
  73
  74   /* Name space code.  */
  75
  76   ENUM_BITFIELD(domain_enum_tag) domain : SYMBOL_DOMAIN_BITS;
  77
  78   /* Address class (for info_symbols).  Note that we don't allow
  79      synthetic "aclass" values here at present, simply because there's
  80      no need.  */
  81
  82   ENUM_BITFIELD(address_class) aclass : SYMBOL_ACLASS_BITS;
  83 };
  84
  85 /* This struct is size-critical (see comment at the to of symtab.h), so this
  86    assert makes sure the size doesn't change accidentally.  Be careful when
  87    purposely increasing the size.  */
  88 gdb_static_assert ((sizeof (void *) == 8 && sizeof (partial_symbol) == 40)
  89                    || (sizeof (void *) == 4 && sizeof (partial_symbol) == 24));
  90
  91 /* A convenience enum to give names to some constants used when
  92    searching psymtabs.  This is internal to psymtab and should not be
  93    used elsewhere.  */
  94
  95 enum psymtab_search_status
  96   {
  97     PST_NOT_SEARCHED,
  98     PST_SEARCHED_AND_FOUND,
  99     PST_SEARCHED_AND_NOT_FOUND
 100   };
 101
 102 /* Each source file that has not been fully read in is represented by
 103    a partial_symtab.  This contains the information on where in the
 104    executable the debugging symbols for a specific file are, and a
 105    list of names of global symbols which are located in this file.
 106    They are all chained on partial symtab lists.
 107
 108    Even after the source file has been read into a symtab, the
 109    partial_symtab remains around.  They are allocated on an obstack,
 110    objfile_obstack.  */
 111
 112 struct partial_symtab
 113 {
 114   /* Return the raw low text address of this partial_symtab.  */
 115   CORE_ADDR raw_text_low () const
 116   {
 117     return m_text_low;
 118   }
 119
 120   /* Return the raw high text address of this partial_symtab.  */
 121   CORE_ADDR raw_text_high () const
 122   {
 123     return m_text_high;
 124   }
 125
 126   /* Return the relocated low text address of this partial_symtab.  */
 127   CORE_ADDR text_low (struct objfile *objfile) const
 128   {
 129     return m_text_low + ANOFFSET (objfile->section_offsets,
 130                                   SECT_OFF_TEXT (objfile));
 131   }
 132
 133   /* Return the relocated high text address of this partial_symtab.  */
 134   CORE_ADDR text_high (struct objfile *objfile) const
 135   {
 136     return m_text_high + ANOFFSET (objfile->section_offsets,
 137                                    SECT_OFF_TEXT (objfile));
 138   }
 139
 140   /* Set the low text address of this partial_symtab.  */
 141   void set_text_low (CORE_ADDR addr)
 142   {
 143     m_text_low = addr;
 144     text_low_valid = 1;
 145   }
 146
 147   /* Set the hight text address of this partial_symtab.  */
 148   void set_text_high (CORE_ADDR addr)
 149   {
 150     m_text_high = addr;
 151     text_high_valid = 1;
 152   }
 153
 154
 155   /* Chain of all existing partial symtabs.  */
 156
 157   struct partial_symtab *next;
 158
 159   /* Name of the source file which this partial_symtab defines,
 160      or if the psymtab is anonymous then a descriptive name for
 161      debugging purposes, or "".  It must not be NULL.  */
 162
 163   const char *filename;
 164
 165   /* Full path of the source file.  NULL if not known.  */
 166
 167   char *fullname;
 168
 169   /* Directory in which it was compiled, or NULL if we don't know.  */
 170
 171   const char *dirname;
 172
 173   /* Range of text addresses covered by this file; texthigh is the
 174      beginning of the next section.  Do not use if PSYMTABS_ADDRMAP_SUPPORTED
 175      is set.  Do not refer directly to these fields.  Instead, use the
 176      accessors.  The validity of these fields is determined by the
 177      text_low_valid and text_high_valid fields; these are located later
 178      in this structure for better packing.  */
 179
 180   CORE_ADDR m_text_low;
 181   CORE_ADDR m_text_high;
 182
 183   /* If NULL, this is an ordinary partial symbol table.
 184
 185      If non-NULL, this holds a single includer of this partial symbol
 186      table, and this partial symbol table is a shared one.
 187
 188      A shared psymtab is one that is referenced by multiple other
 189      psymtabs, and which conceptually has its contents directly
 190      included in those.
 191
 192      Shared psymtabs have special semantics.  When a search finds a
 193      symbol in a shared table, we instead return one of the non-shared
 194      tables that include this one.
 195
 196      A shared psymtabs can be referred to by other shared ones.
 197
 198      The psymtabs that refer to a shared psymtab will list the shared
 199      psymtab in their 'dependencies' array.
 200
 201      In DWARF terms, a shared psymtab is a DW_TAG_partial_unit; but
 202      of course using a name based on that would be too confusing, so
 203      "shared" was chosen instead.
 204
 205      Only a single user is needed because, when expanding a shared
 206      psymtab, we only need to expand its "canonical" non-shared user.
 207      The choice of which one should be canonical is left to the
 208      debuginfo reader; it can be arbitrary.  */
 209
 210   struct partial_symtab *user;
 211
 212   /* Array of pointers to all of the partial_symtab's which this one
 213      depends on.  Since this array can only be set to previous or
 214      the current (?) psymtab, this dependency tree is guaranteed not
 215      to have any loops.  "depends on" means that symbols must be read
 216      for the dependencies before being read for this psymtab; this is
 217      for type references in stabs, where if foo.c includes foo.h, declarations
 218      in foo.h may use type numbers defined in foo.c.  For other debugging
 219      formats there may be no need to use dependencies.  */
 220
 221   struct partial_symtab **dependencies;
 222
 223   int number_of_dependencies;
 224
 225   /* Global symbol list.  This list will be sorted after readin to
 226      improve access.  Binary search will be the usual method of
 227      finding a symbol within it.  globals_offset is an integer offset
 228      within global_psymbols[].  */
 229
 230   int globals_offset;
 231   int n_global_syms;
 232
 233   /* Static symbol list.  This list will *not* be sorted after readin;
 234      to find a symbol in it, exhaustive search must be used.  This is
 235      reasonable because searches through this list will eventually
 236      lead to either the read in of a files symbols for real (assumed
 237      to take a *lot* of time; check) or an error (and we don't care
 238      how long errors take).  This is an offset and size within
 239      static_psymbols[].  */
 240
 241   int statics_offset;
 242   int n_static_syms;
 243
 244   /* Non-zero if the symtab corresponding to this psymtab has been
 245      readin.  This is located here so that this structure packs better
 246      on 64-bit systems.  */
 247
 248   unsigned char readin;
 249
 250   /* True iff objfile->psymtabs_addrmap is properly populated for this
 251      partial_symtab.  For discontiguous overlapping psymtabs is the only usable
 252      info in PSYMTABS_ADDRMAP.  */
 253
 254   unsigned char psymtabs_addrmap_supported;
 255
 256   /* True if the name of this partial symtab is not a source file name.  */
 257
 258   unsigned char anonymous;
 259
 260   /* A flag that is temporarily used when searching psymtabs.  */
 261
 262   ENUM_BITFIELD (psymtab_search_status) searched_flag : 2;
 263
 264   /* Validity of the m_text_low and m_text_high fields.  */
 265
 266   unsigned int text_low_valid : 1;
 267   unsigned int text_high_valid : 1;
 268
 269   /* Pointer to compunit eventually allocated for this source file, 0 if
 270      !readin or if we haven't looked for the symtab after it was readin.  */
 271
 272   struct compunit_symtab *compunit_symtab;
 273
 274   /* Pointer to function which will read in the symtab corresponding to
 275      this psymtab.  */
 276
 277   void (*read_symtab) (struct partial_symtab *, struct objfile *);
 278
 279   /* Information that lets read_symtab() locate the part of the symbol table
 280      that this psymtab corresponds to.  This information is private to the
 281      format-dependent symbol reading routines.  For further detail examine
 282      the various symbol reading modules.  */
 283
 284   void *read_symtab_private;
 285 };
 286
 287 /* Specify whether a partial psymbol should be allocated on the global
 288    list or the static list.  */
 289
 290 enum class psymbol_placement
 291 {
 292   STATIC,
 293   GLOBAL
 294 };
 295
 296 /* Add a symbol to the partial symbol table of OBJFILE.
 297
 298    If COPY_NAME is true, make a copy of NAME, otherwise use the passed
 299    reference.
 300
 301    THECLASS is the type of symbol.
 302
 303    SECTION is the index of the section of OBJFILE in which the symbol is found.
 304
 305    WHERE determines whether the symbol goes in the list of static or global
 306    partial symbols of OBJFILE.
 307
 308    COREADDR is the address of the symbol.  For partial symbols that don't have
 309    an address, zero is passed.
 310
 311    LANGUAGE is the language from which the symbol originates.  This will
 312    influence, amongst other things, how the symbol name is demangled. */
 313
 314 extern void add_psymbol_to_list (gdb::string_view name,
 315                                  bool copy_name, domain_enum domain,
 316                                  enum address_class theclass,
 317                                  short section,
 318                                  psymbol_placement where,
 319                                  CORE_ADDR coreaddr,
 320                                  enum language language,
 321                                  struct objfile *objfile);
 322
 323 /* Initialize storage for partial symbols.  If partial symbol storage
 324    has already been initialized, this does nothing.  TOTAL_SYMBOLS is
 325    an estimate of how many symbols there will be.  */
 326
 327 extern void init_psymbol_list (struct objfile *objfile, int total_symbols);
 328
 329 extern struct partial_symtab *start_psymtab_common (struct objfile *,
 330                                                     const char *, CORE_ADDR);
 331
 332 extern void end_psymtab_common (struct objfile *, struct partial_symtab *);
 333
 334 /* Allocate a new partial symbol table associated with OBJFILE.
 335    FILENAME (which must be non-NULL) is the filename of this partial
 336    symbol table; it is copied into the appropriate storage.  A new
 337    partial symbol table is returned; aside from "next" and "filename",
 338    its fields are initialized to zero.  */
 339
 340 extern struct partial_symtab *allocate_psymtab (const char *filename,
 341                                                 struct objfile *objfile)
 342   ATTRIBUTE_NONNULL (1);
 343
 344 static inline void
 345 discard_psymtab (struct objfile *objfile, struct partial_symtab *pst)
 346 {
 347   objfile->partial_symtabs->discard_psymtab (pst);
 348 }
 349
 350 /* Used when recording partial symbol tables.  On destruction,
 351    discards any partial symbol tables that have been built.  However,
 352    the tables can be kept by calling the "keep" method.  */
 353 class psymtab_discarder
 354 {
 355  public:
 356
 357   psymtab_discarder (struct objfile *objfile)
 358     : m_objfile (objfile),
 359       m_psymtab (objfile->partial_symtabs->psymtabs)
 360   {
 361   }
 362
 363   ~psymtab_discarder ()
 364   {
 365     if (m_objfile != NULL)
 366       m_objfile->partial_symtabs->discard_psymtabs_to (m_psymtab);
 367   }
 368
 369   /* Keep any partial symbol tables that were built.  */
 370   void keep ()
 371   {
 372     m_objfile = NULL;
 373   }
 374
 375  private:
 376
 377   /* The objfile.  If NULL this serves as a sentinel to indicate that
 378      the psymtabs should be kept.  */
 379   struct objfile *m_objfile;
 380   /* How far back to free.  */
 381   struct partial_symtab *m_psymtab;
 382 };
 383
 384 #endif /* PSYMPRIV_H */