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 "gdbsupport/next-iterator.h"
  26 #include "bcache.h"
  27
  28 struct partial_symbol;
  29
  30 /* An instance of this class manages the partial symbol tables and
  31    partial symbols for a given objfile.
  32
  33    The core psymtab functions -- those in psymtab.c -- arrange for
  34    nearly all psymtab- and psymbol-related allocations to happen
  35    either in the psymtab_storage object (either on its obstack or in
  36    other memory managed by this class), or on the per-BFD object.  The
  37    only link from the psymtab storage object back to the objfile (or
  38    objfile_obstack) that is made by the core psymtab code is the
  39    compunit_symtab member in the psymtab.
  40
  41    However, it is up to each symbol reader to maintain this invariant
  42    in other ways, if it wants to reuse psymtabs across multiple
  43    objfiles.  The main issue here is ensuring that read_symtab_private
  44    does not point into objfile_obstack.  */
  45
  46 class psymtab_storage
  47 {
  48 public:
  49
  50   psymtab_storage ();
  51
  52   ~psymtab_storage ();
  53
  54   DISABLE_COPY_AND_ASSIGN (psymtab_storage);
  55
  56   /* Discard all partial symbol tables starting with "psymtabs" and
  57      proceeding until "to" has been discarded.  */
  58
  59   void discard_psymtabs_to (struct partial_symtab *to)
  60   {
  61     while (psymtabs != to)
  62       discard_psymtab (psymtabs);
  63   }
  64
  65   /* Discard the partial symbol table.  */
  66
  67   void discard_psymtab (struct partial_symtab *pst);
  68
  69   /* Return the obstack that is used for storage by this object.  */
  70
  71   struct obstack *obstack ()
  72   {
  73     if (!m_obstack.has_value ())
  74       m_obstack.emplace ();
  75     return &*m_obstack;
  76   }
  77
  78   /* Allocate storage for the "dependencies" field of a psymtab.
  79      NUMBER says how many dependencies there are.  */
  80
  81   struct partial_symtab **allocate_dependencies (int number)
  82   {
  83     return OBSTACK_CALLOC (obstack (), number, struct partial_symtab *);
  84   }
  85
  86   /* Allocate a new psymtab on the psymtab obstack.  The new psymtab
  87      will be linked in to the "psymtabs" list, but otherwise all other
  88      fields will be zero.  */
  89
  90   struct partial_symtab *allocate_psymtab ();
  91
  92   typedef next_adapter<struct partial_symtab> partial_symtab_range;
  93
  94   /* A range adapter that makes it possible to iterate over all
  95      psymtabs in one objfile.  */
  96
  97   partial_symtab_range range ()
  98   {
  99     return partial_symtab_range (psymtabs);
 100   }
 101
 102
 103   /* Each objfile points to a linked list of partial symtabs derived from
 104      this file, one partial symtab structure for each compilation unit
 105      (source file).  */
 106
 107   struct partial_symtab *psymtabs = nullptr;
 108
 109   /* Map addresses to the entries of PSYMTABS.  It would be more efficient to
 110      have a map per the whole process but ADDRMAP cannot selectively remove
 111      its items during FREE_OBJFILE.  This mapping is already present even for
 112      PARTIAL_SYMTABs which still have no corresponding full SYMTABs read.
 113
 114      The DWARF parser reuses this addrmap to store things other than
 115      psymtabs in the cases where debug information is being read from, for
 116      example, the .debug-names section.  */
 117
 118   struct addrmap *psymtabs_addrmap = nullptr;
 119
 120   /* A byte cache where we can stash arbitrary "chunks" of bytes that
 121      will not change.  */
 122
 123   gdb::bcache psymbol_cache;
 124
 125   /* Vectors of all partial symbols read in from file.  The actual data
 126      is stored in the objfile_obstack.  */
 127
 128   std::vector<partial_symbol *> global_psymbols;
 129   std::vector<partial_symbol *> static_psymbols;
 130
 131 private:
 132
 133   /* List of freed partial symtabs, available for re-use.  */
 134
 135   struct partial_symtab *free_psymtabs = nullptr;
 136
 137   /* The obstack where allocations are made.  This is lazily allocated
 138      so that we don't waste memory when there are no psymtabs.  */
 139
 140   gdb::optional<auto_obstack> m_obstack;
 141 };
 142
 143
 144 extern const struct quick_symbol_functions psym_functions;
 145
 146 extern const struct quick_symbol_functions dwarf2_gdb_index_functions;
 147 extern const struct quick_symbol_functions dwarf2_debug_names_functions;
 148
 149 /* Ensure that the partial symbols for OBJFILE have been loaded.  If
 150    VERBOSE is true, then this will print a message when symbols
 151    are loaded.  This function returns a range adapter suitable for
 152    iterating over the psymtabs of OBJFILE.  */
 153
 154 extern psymtab_storage::partial_symtab_range require_partial_symbols
 155     (struct objfile *objfile, bool verbose);
 156
 157 #endif /* PSYMTAB_H */