gold/gdb-index.h

   1 // gdb-index.h -- generate .gdb_index section for fast debug lookup  -*- C++ -*-
   2
   3 // Copyright (C) 2012-2022 Free Software Foundation, Inc.
   4 // Written by Cary Coutant <ccoutant@google.com>.
   5
   6 // This file is part of gold.
   7
   8 // This program is free software; you can redistribute it and/or modify
   9 // it under the terms of the GNU General Public License as published by
  10 // the Free Software Foundation; either version 3 of the License, or
  11 // (at your option) any later version.
  12
  13 // This program is distributed in the hope that it will be useful,
  14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 // GNU General Public License for more details.
  17
  18 // You should have received a copy of the GNU General Public License
  19 // along with this program; if not, write to the Free Software
  20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  21 // MA 02110-1301, USA.
  22
  23 #include <sys/types.h>
  24 #include <vector>
  25
  26 #include "gold.h"
  27 #include "output.h"
  28 #include "mapfile.h"
  29 #include "stringpool.h"
  30
  31 #ifndef GOLD_GDB_INDEX_H
  32 #define GOLD_GDB_INDEX_H
  33
  34 namespace gold
  35 {
  36
  37 class Output_section;
  38 class Output_file;
  39 class Mapfile;
  40 template<int size, bool big_endian>
  41 class Sized_relobj;
  42 class Dwarf_range_list;
  43 template <typename T>
  44 class Gdb_hashtab;
  45 class Gdb_index_info_reader;
  46 class Dwarf_pubnames_table;
  47
  48 // This class manages the .gdb_index section, which is a fast
  49 // lookup table for DWARF information used by the gdb debugger.
  50 // The format of this section is described in gdb/doc/gdb.texinfo.
  51
  52 class Gdb_index : public Output_section_data
  53 {
  54  public:
  55   Gdb_index(Output_section* gdb_index_section);
  56
  57   ~Gdb_index();
  58
  59   // Scan a .debug_info or .debug_types input section.
  60   void scan_debug_info(bool is_type_unit,
  61                        Relobj* object,
  62                        const unsigned char* symbols,
  63                        off_t symbols_size,
  64                        unsigned int shndx,
  65                        unsigned int reloc_shndx,
  66                        unsigned int reloc_type);
  67
  68   // Add a compilation unit.
  69   int
  70   add_comp_unit(off_t cu_offset, off_t cu_length)
  71   {
  72     this->comp_units_.push_back(Comp_unit(cu_offset, cu_length));
  73     return this->comp_units_.size() - 1;
  74   }
  75
  76   // Add a type unit.
  77   int
  78   add_type_unit(off_t tu_offset, off_t type_offset, uint64_t signature)
  79   {
  80     this->type_units_.push_back(Type_unit(tu_offset, type_offset, signature));
  81     return this->type_units_.size() - 1;
  82   }
  83
  84   // Add an address range.
  85   void
  86   add_address_range_list(Relobj* object, unsigned int cu_index,
  87                          Dwarf_range_list* ranges)
  88   {
  89     this->ranges_.push_back(Per_cu_range_list(object, cu_index, ranges));
  90   }
  91
  92   // Add a symbol.  FLAGS are the gdb_index version 7 flags to be stored in
  93   // the high-byte of the cu_index field.
  94   void
  95   add_symbol(int cu_index, const char* sym_name, uint8_t flags);
  96
  97   // Return the offset into the pubnames table for the cu at the given
  98   // offset.
  99   off_t
 100   find_pubname_offset(off_t cu_offset);
 101
 102   // Return the offset into the pubtypes table for the cu at the
 103   // given offset.
 104   off_t
 105   find_pubtype_offset(off_t cu_offset);
 106
 107   // Return TRUE if we have already processed the pubnames and types
 108   // set for OBJECT of the CUs and TUS associated with the statement
 109   // list at OFFSET.
 110   bool
 111   pubnames_read(const Relobj* object, off_t offset);
 112
 113   // Record that we have already read the pubnames associated with
 114   // OBJECT and OFFSET.
 115   void
 116   set_pubnames_read(const Relobj* object, off_t offset);
 117
 118   // Return a pointer to the given table.
 119   Dwarf_pubnames_table*
 120   pubnames_table()
 121   { return pubnames_table_; }
 122
 123   Dwarf_pubnames_table*
 124   pubtypes_table()
 125   { return pubtypes_table_; }
 126
 127   // Print usage statistics.
 128   static void
 129   print_stats();
 130
 131  protected:
 132   // This is called to update the section size prior to assigning
 133   // the address and file offset.
 134   void
 135   update_data_size()
 136   { this->set_final_data_size(); }
 137
 138   // Set the final data size.
 139   void
 140   set_final_data_size();
 141
 142   // Write the data to the file.
 143   void
 144   do_write(Output_file*);
 145
 146   // Write to a map file.
 147   void
 148   do_print_to_mapfile(Mapfile* mapfile) const
 149   { mapfile->print_output_data(this, _("** gdb_index")); }
 150
 151   // Create a map from dies to pubnames.
 152   Dwarf_pubnames_table*
 153   map_pubtable_to_dies(unsigned int attr,
 154                        Gdb_index_info_reader* dwinfo,
 155                        Relobj* object,
 156                        const unsigned char* symbols,
 157                        off_t symbols_size);
 158
 159   // Wrapper for map_pubtable_to_dies
 160   void
 161   map_pubnames_and_types_to_dies(Gdb_index_info_reader* dwinfo,
 162                                  Relobj* object,
 163                                  const unsigned char* symbols,
 164                                  off_t symbols_size);
 165
 166  private:
 167   // An entry in the compilation unit list.
 168   struct Comp_unit
 169   {
 170     Comp_unit(off_t off, off_t len)
 171       : cu_offset(off), cu_length(len)
 172     { }
 173     uint64_t cu_offset;
 174     uint64_t cu_length;
 175   };
 176
 177   // An entry in the type unit list.
 178   struct Type_unit
 179   {
 180     Type_unit(off_t off, off_t toff, uint64_t sig)
 181       : tu_offset(off), type_offset(toff), type_signature(sig)
 182     { }
 183     uint64_t tu_offset;
 184     uint64_t type_offset;
 185     uint64_t type_signature;
 186   };
 187
 188   // An entry in the address range list.
 189   struct Per_cu_range_list
 190   {
 191     Per_cu_range_list(Relobj* obj, uint32_t index, Dwarf_range_list* r)
 192       : object(obj), cu_index(index), ranges(r)
 193     { }
 194     Relobj* object;
 195     uint32_t cu_index;
 196     Dwarf_range_list* ranges;
 197   };
 198
 199   // A symbol table entry.
 200   struct Gdb_symbol
 201   {
 202     Stringpool::Key name_key;
 203     unsigned int hashval;
 204     unsigned int cu_vector_index;
 205
 206     // Return the hash value.
 207     unsigned int
 208     hash()
 209     { return this->hashval; }
 210
 211     // Return true if this symbol is the same as SYMBOL.
 212     bool
 213     equal(Gdb_symbol* symbol)
 214     { return this->name_key == symbol->name_key; }
 215   };
 216
 217   typedef std::vector<std::pair<int, uint8_t> > Cu_vector;
 218
 219   typedef Unordered_map<off_t, off_t> Pubname_offset_map;
 220   Pubname_offset_map cu_pubname_map_;
 221   Pubname_offset_map cu_pubtype_map_;
 222
 223   // Scan the given pubtable and build a map of the various dies it
 224   // refers to, so we can process the entries when we encounter the
 225   // die.
 226   void
 227   map_pubtable_to_dies(Dwarf_pubnames_table* table,
 228                        Pubname_offset_map* map);
 229
 230   // Tables to store the pubnames section of the current object.
 231   Dwarf_pubnames_table* pubnames_table_;
 232   Dwarf_pubnames_table* pubtypes_table_;
 233
 234   // The .gdb_index section.
 235   Output_section* gdb_index_section_;
 236   // The list of DWARF compilation units.
 237   std::vector<Comp_unit> comp_units_;
 238   // The list of DWARF type units.
 239   std::vector<Type_unit> type_units_;
 240   // The list of address ranges.
 241   std::vector<Per_cu_range_list> ranges_;
 242   // The symbol table.
 243   Gdb_hashtab<Gdb_symbol>* gdb_symtab_;
 244   // The CU vector portion of the constant pool.
 245   std::vector<Cu_vector*> cu_vector_list_;
 246   // An array to map from a CU vector index to an offset to the constant pool.
 247   off_t* cu_vector_offsets_;
 248   // The string portion of the constant pool.
 249   Stringpool stringpool_;
 250   // Offsets of the various pieces of the .gdb_index section.
 251   off_t tu_offset_;
 252   off_t addr_offset_;
 253   off_t symtab_offset_;
 254   off_t cu_pool_offset_;
 255   off_t stringpool_offset_;
 256   // Object, stmt list offset of the CUs and TUs associated with the
 257   // last read pubnames and pubtypes sections.
 258   const Relobj* pubnames_object_;
 259   off_t stmt_list_offset_;
 260 };
 261
 262 } // End namespace gold.
 263
 264 #endif // !defined(GOLD_GDB_INDEX_H)