gdb/psymtab.h

   1 /* Public 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 PSYMTAB_H
  21 #define PSYMTAB_H
  22
  23 #include "gdb_obstack.h"
  24 #include "symfile.h"
  25 #include "common/next-iterator.h"
  26
  27 struct partial_symbol;
  28
  29 /* A bcache for partial symbols.  */
  30
  31 struct psymbol_bcache;
  32
  33 /* An instance of this class manages the partial symbol tables and
  34    partial symbols for a given objfile.
  35
  36    The core psymtab functions -- those in psymtab.c -- arrange for
  37    nearly all psymtab- and psymbol-related allocations to happen
  38    either in the psymtab_storage object (either on its obstack or in
  39    other memory managed by this class), or on the per-BFD object.  The
  40    only link from the psymtab storage object back to the objfile (or
  41    objfile_obstack) that is made by the core psymtab code is the
  42    compunit_symtab member in the psymtab.
  43
  44    However, it is up to each symbol reader to maintain this invariant
  45    in other ways, if it wants to reuse psymtabs across multiple
  46    objfiles.  The main issue here is ensuring that read_symtab_private
  47    does not point into objfile_obstack.  */
  48
  49 class psymtab_storage
  50 {
  51 public:
  52
  53   psymtab_storage ();
  54
  55   ~psymtab_storage ();
  56
  57   DISABLE_COPY_AND_ASSIGN (psymtab_storage);
  58
  59   /* Discard all partial symbol tables starting with "psymtabs" and
  60      proceeding until "to" has been discarded.  */
  61
  62   void discard_psymtabs_to (struct partial_symtab *to)
  63   {
  64     while (psymtabs != to)
  65       discard_psymtab (psymtabs);
  66   }
  67
  68   /* Discard the partial symbol table.  */
  69
  70   void discard_psymtab (struct partial_symtab *pst);
  71
  72   /* Return the obstack that is used for storage by this object.  */
  73
  74   struct obstack *obstack ()
  75   {
  76     if (!m_obstack.has_value ())
  77       m_obstack.emplace ();
  78     return &*m_obstack;
  79   }
  80
  81   /* Allocate storage for the "dependencies" field of a psymtab.
  82      NUMBER says how many dependencies there are.  */
  83
  84   struct partial_symtab **allocate_dependencies (int number)
  85   {
  86     return OBSTACK_CALLOC (obstack (), number, struct partial_symtab *);
  87   }
  88
  89   /* Allocate a new psymtab on the psymtab obstack.  The new psymtab
  90      will be linked in to the "psymtabs" list, but otherwise all other
  91      fields will be zero.  */
  92
  93   struct partial_symtab *allocate_psymtab ();
  94
  95
  96   /* Each objfile points to a linked list of partial symtabs derived from
  97      this file, one partial symtab structure for each compilation unit
  98      (source file).  */
  99
 100   struct partial_symtab *psymtabs = nullptr;
 101
 102   /* Map addresses to the entries of PSYMTABS.  It would be more efficient to
 103      have a map per the whole process but ADDRMAP cannot selectively remove
 104      its items during FREE_OBJFILE.  This mapping is already present even for
 105      PARTIAL_SYMTABs which still have no corresponding full SYMTABs read.  */
 106
 107   struct addrmap *psymtabs_addrmap = nullptr;
 108
 109   /* A byte cache where we can stash arbitrary "chunks" of bytes that
 110      will not change.  */
 111
 112   struct psymbol_bcache *psymbol_cache;
 113
 114   /* Vectors of all partial symbols read in from file.  The actual data
 115      is stored in the objfile_obstack.  */
 116
 117   std::vector<partial_symbol *> global_psymbols;
 118   std::vector<partial_symbol *> static_psymbols;
 119
 120 private:
 121
 122   /* List of freed partial symtabs, available for re-use.  */
 123
 124   struct partial_symtab *free_psymtabs = nullptr;
 125
 126   /* The obstack where allocations are made.  This is lazily allocated
 127      so that we don't waste memory when there are no psymtabs.  */
 128
 129   gdb::optional<auto_obstack> m_obstack;
 130 };
 131
 132
 133 extern struct psymbol_bcache *psymbol_bcache_init (void);
 134 extern void psymbol_bcache_free (struct psymbol_bcache *);
 135 extern struct bcache *psymbol_bcache_get_bcache (struct psymbol_bcache *);
 136
 137 extern const struct quick_symbol_functions psym_functions;
 138
 139 extern const struct quick_symbol_functions dwarf2_gdb_index_functions;
 140 extern const struct quick_symbol_functions dwarf2_debug_names_functions;
 141
 142 /* Ensure that the partial symbols for OBJFILE have been loaded.  If
 143    VERBOSE is non-zero, then this will print a message when symbols
 144    are loaded.  This function returns a range adapter suitable for
 145    iterating over the psymtabs of OBJFILE.  */
 146
 147 class objfile_psymtabs;
 148 extern objfile_psymtabs require_partial_symbols (struct objfile *objfile,
 149                                                  int verbose);
 150
 151 #endif /* PSYMTAB_H */