// gdb-index.h -- generate .gdb_index section for fast debug lookup  -*- C++ -*-

// Copyright (C) 2012-2024 Free Software Foundation, Inc.
// Written by Cary Coutant <[email protected]>.

// This file is part of gold.

// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
// MA 02110-1301, USA.

#include <sys/types.h>
#include <vector>

#include "gold.h"
#include "output.h"
#include "mapfile.h"
#include "stringpool.h"

#ifndef GOLD_GDB_INDEX_H
#define GOLD_GDB_INDEX_H

namespace gold
{

class Output_section;
class Output_file;
class Mapfile;
template<int size, bool big_endian>
class Sized_relobj;
class Dwarf_range_list;
template <typename T>
class Gdb_hashtab;
class Gdb_index_info_reader;
class Dwarf_pubnames_table;

// This class manages the .gdb_index section, which is a fast
// lookup table for DWARF information used by the gdb debugger.
// The format of this section is described in gdb/doc/gdb.texinfo.

class Gdb_index : public Output_section_data
{
public:
 Gdb_index(Output_section* gdb_index_section);

 ~Gdb_index();

 // Scan a .debug_info or .debug_types input section.
 void scan_debug_info(bool is_type_unit,
                      Relobj* object,
                      const unsigned char* symbols,
                      off_t symbols_size,
                      unsigned int shndx,
                      unsigned int reloc_shndx,
                      unsigned int reloc_type);

 // Add a compilation unit.
 int
 add_comp_unit(off_t cu_offset, off_t cu_length)
 {
   this->comp_units_.push_back(Comp_unit(cu_offset, cu_length));
   return this->comp_units_.size() - 1;
 }

 // Add a type unit.
 int
 add_type_unit(off_t tu_offset, off_t type_offset, uint64_t signature)
 {
   this->type_units_.push_back(Type_unit(tu_offset, type_offset, signature));
   return this->type_units_.size() - 1;
 }

 // Add an address range.
 void
 add_address_range_list(Relobj* object, unsigned int cu_index,
                        Dwarf_range_list* ranges)
 {
   this->ranges_.push_back(Per_cu_range_list(object, cu_index, ranges));
 }

 // Add a symbol.  FLAGS are the gdb_index version 7 flags to be stored in
 // the high-byte of the cu_index field.
 void
 add_symbol(int cu_index, const char* sym_name, uint8_t flags);

 // Return the offset into the pubnames table for the cu at the given
 // offset.
 off_t
 find_pubname_offset(off_t cu_offset);

 // Return the offset into the pubtypes table for the cu at the
 // given offset.
 off_t
 find_pubtype_offset(off_t cu_offset);

 // Return TRUE if we have already processed the pubnames and types
 // set for OBJECT of the CUs and TUS associated with the statement
 // list at OFFSET.
 bool
 pubnames_read(const Relobj* object, off_t offset);

 // Record that we have already read the pubnames associated with
 // OBJECT and OFFSET.
 void
 set_pubnames_read(const Relobj* object, off_t offset);

 // Return a pointer to the given table.
 Dwarf_pubnames_table*
 pubnames_table()
 { return pubnames_table_; }

 Dwarf_pubnames_table*
 pubtypes_table()
 { return pubtypes_table_; }

 // Print usage statistics.
 static void
 print_stats();

protected:
 // This is called to update the section size prior to assigning
 // the address and file offset.
 void
 update_data_size()
 { this->set_final_data_size(); }

 // Set the final data size.
 void
 set_final_data_size();

 // Write the data to the file.
 void
 do_write(Output_file*);

 // Write to a map file.
 void
 do_print_to_mapfile(Mapfile* mapfile) const
 { mapfile->print_output_data(this, _("** gdb_index")); }

 // Create a map from dies to pubnames.
 Dwarf_pubnames_table*
 map_pubtable_to_dies(unsigned int attr,
                      Gdb_index_info_reader* dwinfo,
                      Relobj* object,
                      const unsigned char* symbols,
                      off_t symbols_size);

 // Wrapper for map_pubtable_to_dies
 void
 map_pubnames_and_types_to_dies(Gdb_index_info_reader* dwinfo,
                                Relobj* object,
                                const unsigned char* symbols,
                                off_t symbols_size);

private:
 // An entry in the compilation unit list.
 struct Comp_unit
 {
   Comp_unit(off_t off, off_t len)
     : cu_offset(off), cu_length(len)
   { }
   uint64_t cu_offset;
   uint64_t cu_length;
 };

 // An entry in the type unit list.
 struct Type_unit
 {
   Type_unit(off_t off, off_t toff, uint64_t sig)
     : tu_offset(off), type_offset(toff), type_signature(sig)
   { }
   uint64_t tu_offset;
   uint64_t type_offset;
   uint64_t type_signature;
 };

 // An entry in the address range list.
 struct Per_cu_range_list
 {
   Per_cu_range_list(Relobj* obj, uint32_t index, Dwarf_range_list* r)
     : object(obj), cu_index(index), ranges(r)
   { }
   Relobj* object;
   uint32_t cu_index;
   Dwarf_range_list* ranges;
 };

 // A symbol table entry.
 struct Gdb_symbol
 {
   Stringpool::Key name_key;
   unsigned int hashval;
   unsigned int cu_vector_index;

   // Return the hash value.
   unsigned int
   hash()
   { return this->hashval; }

   // Return true if this symbol is the same as SYMBOL.
   bool
   equal(Gdb_symbol* symbol)
   { return this->name_key == symbol->name_key; }
 };

 typedef std::vector<std::pair<int, uint8_t> > Cu_vector;

 typedef Unordered_map<off_t, off_t> Pubname_offset_map;
 Pubname_offset_map cu_pubname_map_;
 Pubname_offset_map cu_pubtype_map_;

 // Scan the given pubtable and build a map of the various dies it
 // refers to, so we can process the entries when we encounter the
 // die.
 void
 map_pubtable_to_dies(Dwarf_pubnames_table* table,
                      Pubname_offset_map* map);

 // Tables to store the pubnames section of the current object.
 Dwarf_pubnames_table* pubnames_table_;
 Dwarf_pubnames_table* pubtypes_table_;

 // The .gdb_index section.
 Output_section* gdb_index_section_;
 // The list of DWARF compilation units.
 std::vector<Comp_unit> comp_units_;
 // The list of DWARF type units.
 std::vector<Type_unit> type_units_;
 // The list of address ranges.
 std::vector<Per_cu_range_list> ranges_;
 // The symbol table.
 Gdb_hashtab<Gdb_symbol>* gdb_symtab_;
 // The CU vector portion of the constant pool.
 std::vector<Cu_vector*> cu_vector_list_;
 // An array to map from a CU vector index to an offset to the constant pool.
 off_t* cu_vector_offsets_;
 // The string portion of the constant pool.
 Stringpool stringpool_;
 // Offsets of the various pieces of the .gdb_index section.
 off_t tu_offset_;
 off_t addr_offset_;
 off_t symtab_offset_;
 off_t cu_pool_offset_;
 off_t stringpool_offset_;
 // Object, stmt list offset of the CUs and TUs associated with the
 // last read pubnames and pubtypes sections.
 const Relobj* pubnames_object_;
 off_t stmt_list_offset_;
};

} // End namespace gold.

#endif // !defined(GOLD_GDB_INDEX_H)

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