gdb/psymtab.h

   1 /* Public 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 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   /* Install a psymtab on the psymtab list.  This transfers ownership
  87      of PST to this object.  */
  88
  89   void install_psymtab (partial_symtab *pst);
  90
  91   typedef next_adapter<struct partial_symtab> partial_symtab_range;
  92
  93   /* A range adapter that makes it possible to iterate over all
  94      psymtabs in one objfile.  */
  95
  96   partial_symtab_range range ()
  97   {
  98     return partial_symtab_range (psymtabs);
  99   }
 100
 101
 102   /* Each objfile points to a linked list of partial symtabs derived from
 103      this file, one partial symtab structure for each compilation unit
 104      (source file).  */
 105
 106   struct partial_symtab *psymtabs = nullptr;
 107
 108   /* Map addresses to the entries of PSYMTABS.  It would be more efficient to
 109      have a map per the whole process but ADDRMAP cannot selectively remove
 110      its items during FREE_OBJFILE.  This mapping is already present even for
 111      PARTIAL_SYMTABs which still have no corresponding full SYMTABs read.
 112
 113      The DWARF parser reuses this addrmap to store things other than
 114      psymtabs in the cases where debug information is being read from, for
 115      example, the .debug-names section.  */
 116
 117   struct addrmap *psymtabs_addrmap = nullptr;
 118
 119   /* A byte cache where we can stash arbitrary "chunks" of bytes that
 120      will not change.  */
 121
 122   gdb::bcache psymbol_cache;
 123
 124   /* Vectors of all partial symbols read in from file.  The actual data
 125      is stored in the objfile_obstack.  */
 126
 127   std::vector<partial_symbol *> global_psymbols;
 128   std::vector<partial_symbol *> static_psymbols;
 129
 130 private:
 131
 132   /* The obstack where allocations are made.  This is lazily allocated
 133      so that we don't waste memory when there are no psymtabs.  */
 134
 135   gdb::optional<auto_obstack> m_obstack;
 136 };
 137
 138
 139 extern const struct quick_symbol_functions psym_functions;
 140
 141 extern const struct quick_symbol_functions dwarf2_gdb_index_functions;
 142 extern const struct quick_symbol_functions dwarf2_debug_names_functions;
 143
 144 /* Ensure that the partial symbols for OBJFILE have been loaded.  If
 145    VERBOSE is true, then this will print a message when symbols
 146    are loaded.  This function returns a range adapter suitable for
 147    iterating over the psymtabs of OBJFILE.  */
 148
 149 extern psymtab_storage::partial_symtab_range require_partial_symbols
 150     (struct objfile *objfile, bool verbose);
 151
 152 #endif /* PSYMTAB_H */