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   /* Ensure that all the dependencies are read in.  */
 138   void read_dependencies (struct objfile *);
 139
 140   /* Return the raw low text address of this partial_symtab.  */
 141   CORE_ADDR raw_text_low () const
 142   {
 143     return m_text_low;
 144   }
 145
 146   /* Return the raw high text address of this partial_symtab.  */
 147   CORE_ADDR raw_text_high () const
 148   {
 149     return m_text_high;
 150   }
 151
 152   /* Return the relocated low text address of this partial_symtab.  */
 153   CORE_ADDR text_low (struct objfile *objfile) const
 154   {
 155     return m_text_low + objfile->text_section_offset ();
 156   }
 157
 158   /* Return the relocated high text address of this partial_symtab.  */
 159   CORE_ADDR text_high (struct objfile *objfile) const
 160   {
 161     return m_text_high + objfile->text_section_offset ();
 162   }
 163
 164   /* Set the low text address of this partial_symtab.  */
 165   void set_text_low (CORE_ADDR addr)
 166   {
 167     m_text_low = addr;
 168     text_low_valid = 1;
 169   }
 170
 171   /* Set the hight text address of this partial_symtab.  */
 172   void set_text_high (CORE_ADDR addr)
 173   {
 174     m_text_high = addr;
 175     text_high_valid = 1;
 176   }
 177
 178
 179   /* Chain of all existing partial symtabs.  */
 180
 181   struct partial_symtab *next = nullptr;
 182
 183   /* Name of the source file which this partial_symtab defines,
 184      or if the psymtab is anonymous then a descriptive name for
 185      debugging purposes, or "".  It must not be NULL.  */
 186
 187   const char *filename = nullptr;
 188
 189   /* Full path of the source file.  NULL if not known.  */
 190
 191   char *fullname = nullptr;
 192
 193   /* Directory in which it was compiled, or NULL if we don't know.  */
 194
 195   const char *dirname = nullptr;
 196
 197   /* Range of text addresses covered by this file; texthigh is the
 198      beginning of the next section.  Do not use if PSYMTABS_ADDRMAP_SUPPORTED
 199      is set.  Do not refer directly to these fields.  Instead, use the
 200      accessors.  The validity of these fields is determined by the
 201      text_low_valid and text_high_valid fields; these are located later
 202      in this structure for better packing.  */
 203
 204   CORE_ADDR m_text_low = 0;
 205   CORE_ADDR m_text_high = 0;
 206
 207   /* If NULL, this is an ordinary partial symbol table.
 208
 209      If non-NULL, this holds a single includer of this partial symbol
 210      table, and this partial symbol table is a shared one.
 211
 212      A shared psymtab is one that is referenced by multiple other
 213      psymtabs, and which conceptually has its contents directly
 214      included in those.
 215
 216      Shared psymtabs have special semantics.  When a search finds a
 217      symbol in a shared table, we instead return one of the non-shared
 218      tables that include this one.
 219
 220      A shared psymtabs can be referred to by other shared ones.
 221
 222      The psymtabs that refer to a shared psymtab will list the shared
 223      psymtab in their 'dependencies' array.
 224
 225      In DWARF terms, a shared psymtab is a DW_TAG_partial_unit; but
 226      of course using a name based on that would be too confusing, so
 227      "shared" was chosen instead.
 228
 229      Only a single user is needed because, when expanding a shared
 230      psymtab, we only need to expand its "canonical" non-shared user.
 231      The choice of which one should be canonical is left to the
 232      debuginfo reader; it can be arbitrary.  */
 233
 234   struct partial_symtab *user = nullptr;
 235
 236   /* Array of pointers to all of the partial_symtab's which this one
 237      depends on.  Since this array can only be set to previous or
 238      the current (?) psymtab, this dependency tree is guaranteed not
 239      to have any loops.  "depends on" means that symbols must be read
 240      for the dependencies before being read for this psymtab; this is
 241      for type references in stabs, where if foo.c includes foo.h, declarations
 242      in foo.h may use type numbers defined in foo.c.  For other debugging
 243      formats there may be no need to use dependencies.  */
 244
 245   struct partial_symtab **dependencies = nullptr;
 246
 247   int number_of_dependencies = 0;
 248
 249   /* Global symbol list.  This list will be sorted after readin to
 250      improve access.  Binary search will be the usual method of
 251      finding a symbol within it.  globals_offset is an integer offset
 252      within global_psymbols[].  */
 253
 254   int globals_offset = 0;
 255   int n_global_syms = 0;
 256
 257   /* Static symbol list.  This list will *not* be sorted after readin;
 258      to find a symbol in it, exhaustive search must be used.  This is
 259      reasonable because searches through this list will eventually
 260      lead to either the read in of a files symbols for real (assumed
 261      to take a *lot* of time; check) or an error (and we don't care
 262      how long errors take).  This is an offset and size within
 263      static_psymbols[].  */
 264
 265   int statics_offset = 0;
 266   int n_static_syms = 0;
 267
 268   /* True if the symtab corresponding to this psymtab has been readin.
 269      This is located here so that this structure packs better on
 270      64-bit systems.  */
 271
 272   bool readin = false;
 273
 274   /* True iff objfile->psymtabs_addrmap is properly populated for this
 275      partial_symtab.  For discontiguous overlapping psymtabs is the only usable
 276      info in PSYMTABS_ADDRMAP.  */
 277
 278   bool psymtabs_addrmap_supported = false;
 279
 280   /* True if the name of this partial symtab is not a source file name.  */
 281
 282   bool anonymous = false;
 283
 284   /* A flag that is temporarily used when searching psymtabs.  */
 285
 286   ENUM_BITFIELD (psymtab_search_status) searched_flag : 2;
 287
 288   /* Validity of the m_text_low and m_text_high fields.  */
 289
 290   unsigned int text_low_valid : 1;
 291   unsigned int text_high_valid : 1;
 292
 293   /* Pointer to compunit eventually allocated for this source file, 0 if
 294      !readin or if we haven't looked for the symtab after it was readin.  */
 295
 296   struct compunit_symtab *compunit_symtab = nullptr;
 297 };
 298
 299 /* A partial_symtab that works in the historical db way.  This should
 300    not be used in new code, but exists to transition the somewhat
 301    unmaintained "legacy" debug formats.  */
 302
 303 struct legacy_psymtab : public partial_symtab
 304 {
 305   legacy_psymtab (const char *filename, struct objfile *objfile)
 306     : partial_symtab (filename, objfile)
 307   {
 308   }
 309
 310   legacy_psymtab (const char *filename, struct objfile *objfile,
 311                   CORE_ADDR addr)
 312     : partial_symtab (filename, objfile, addr)
 313   {
 314   }
 315
 316   void read_symtab (struct objfile *objf) override
 317   {
 318     if (legacy_read_symtab)
 319       (*legacy_read_symtab) (this, objf);
 320   }
 321
 322   void expand_psymtab (struct objfile *objf) override
 323   {
 324     (*legacy_expand_psymtab) (this, objf);
 325   }
 326
 327   /* Pointer to function which will read in the symtab corresponding to
 328      this psymtab.  */
 329
 330   void (*legacy_read_symtab) (legacy_psymtab *, struct objfile *) = nullptr;
 331
 332   /* Pointer to function which will actually expand this psymtab into
 333      a full symtab.  */
 334
 335   void (*legacy_expand_psymtab) (legacy_psymtab *, struct objfile *) = nullptr;
 336
 337   /* Information that lets read_symtab() locate the part of the symbol table
 338      that this psymtab corresponds to.  This information is private to the
 339      format-dependent symbol reading routines.  For further detail examine
 340      the various symbol reading modules.  */
 341
 342   void *read_symtab_private = nullptr;
 343 };
 344
 345 /* Specify whether a partial psymbol should be allocated on the global
 346    list or the static list.  */
 347
 348 enum class psymbol_placement
 349 {
 350   STATIC,
 351   GLOBAL
 352 };
 353
 354 /* Add a symbol to the partial symbol table of OBJFILE.
 355
 356    If COPY_NAME is true, make a copy of NAME, otherwise use the passed
 357    reference.
 358
 359    THECLASS is the type of symbol.
 360
 361    SECTION is the index of the section of OBJFILE in which the symbol is found.
 362
 363    WHERE determines whether the symbol goes in the list of static or global
 364    partial symbols of OBJFILE.
 365
 366    COREADDR is the address of the symbol.  For partial symbols that don't have
 367    an address, zero is passed.
 368
 369    LANGUAGE is the language from which the symbol originates.  This will
 370    influence, amongst other things, how the symbol name is demangled. */
 371
 372 extern void add_psymbol_to_list (gdb::string_view name,
 373                                  bool copy_name, domain_enum domain,
 374                                  enum address_class theclass,
 375                                  short section,
 376                                  psymbol_placement where,
 377                                  CORE_ADDR coreaddr,
 378                                  enum language language,
 379                                  struct objfile *objfile);
 380
 381 /* Initialize storage for partial symbols.  If partial symbol storage
 382    has already been initialized, this does nothing.  TOTAL_SYMBOLS is
 383    an estimate of how many symbols there will be.  */
 384
 385 extern void init_psymbol_list (struct objfile *objfile, int total_symbols);
 386
 387 extern void end_psymtab_common (struct objfile *, struct partial_symtab *);
 388
 389 static inline void
 390 discard_psymtab (struct objfile *objfile, struct partial_symtab *pst)
 391 {
 392   objfile->partial_symtabs->discard_psymtab (pst);
 393 }
 394
 395 /* Used when recording partial symbol tables.  On destruction,
 396    discards any partial symbol tables that have been built.  However,
 397    the tables can be kept by calling the "keep" method.  */
 398 class psymtab_discarder
 399 {
 400  public:
 401
 402   psymtab_discarder (struct objfile *objfile)
 403     : m_objfile (objfile),
 404       m_psymtab (objfile->partial_symtabs->psymtabs)
 405   {
 406   }
 407
 408   ~psymtab_discarder ()
 409   {
 410     if (m_objfile != NULL)
 411       m_objfile->partial_symtabs->discard_psymtabs_to (m_psymtab);
 412   }
 413
 414   /* Keep any partial symbol tables that were built.  */
 415   void keep ()
 416   {
 417     m_objfile = NULL;
 418   }
 419
 420  private:
 421
 422   /* The objfile.  If NULL this serves as a sentinel to indicate that
 423      the psymtabs should be kept.  */
 424   struct objfile *m_objfile;
 425   /* How far back to free.  */
 426   struct partial_symtab *m_psymtab;
 427 };
 428
 429 #endif /* PSYMPRIV_H */