1 /* Low-level DWARF 2 reading code 2 3 Copyright (C) 1994-2021 Free Software Foundation, Inc. 4 5 Adapted by Gary Funck (gary@intrepid.com), Intrepid Technology, 6 Inc. with support from Florida State University (under contract 7 with the Ada Joint Program Office), and Silicon Graphics, Inc. 8 Initial contribution by Brent Benson, Harris Computer Systems, Inc., 9 based on Fred Fish's (Cygnus Support) implementation of DWARF 1 10 support. 11 12 This file is part of GDB. 13 14 This program is free software; you can redistribute it and/or modify 15 it under the terms of the GNU General Public License as published by 16 the Free Software Foundation; either version 3 of the License, or 17 (at your option) any later version. 18 19 This program is distributed in the hope that it will be useful, 20 but WITHOUT ANY WARRANTY; without even the implied warranty of 21 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 22 GNU General Public License for more details. 23 24 You should have received a copy of the GNU General Public License 25 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 26 27 #ifndef GDB_DWARF2_COMP_UNIT_H 28 #define GDB_DWARF2_COMP_UNIT_H 29 30 #include "dwarf2/leb.h" 31 #include "gdbtypes.h" 32 33 /* The data in a compilation unit header, after target2host 34 translation, looks like this. */ 35 struct comp_unit_head 36 { 37 unsigned int length; 38 unsigned char version; 39 unsigned char addr_size; 40 unsigned char signed_addr_p; 41 sect_offset abbrev_sect_off; 42 43 /* Size of file offsets; either 4 or 8. */ 44 unsigned int offset_size; 45 46 /* Size of the length field; either 4 or 12. */ 47 unsigned int initial_length_size; 48 49 enum dwarf_unit_type unit_type; 50 51 /* Offset to first die in this cu from the start of the cu. 52 This will be the first byte following the compilation unit header. */ 53 cu_offset first_die_cu_offset; 54 55 /* Offset to the first byte of this compilation unit header in the 56 .debug_info section, for resolving relative reference dies. */ 57 sect_offset sect_off; 58 59 /* For types, offset in the type's DIE of the type defined by this TU. */ 60 cu_offset type_cu_offset_in_tu; 61 62 /* 64-bit signature of this unit. For type units, it denotes the signature of 63 the type (DW_UT_type in DWARF 4, additionally DW_UT_split_type in DWARF 5). 64 Also used in DWARF 5, to denote the dwo id when the unit type is 65 DW_UT_skeleton or DW_UT_split_compile. */ 66 ULONGEST signature; 67 68 /* Return the total length of the CU described by this header. */ get_lengthcomp_unit_head69 unsigned int get_length () const 70 { 71 return initial_length_size + length; 72 } 73 74 /* Return TRUE if OFF is within this CU. */ offset_in_cu_pcomp_unit_head75 bool offset_in_cu_p (sect_offset off) const 76 { 77 sect_offset bottom = sect_off; 78 sect_offset top = sect_off + get_length (); 79 return off >= bottom && off < top; 80 } 81 82 /* Read an offset from the data stream. The size of the offset is 83 given by cu_header->offset_size. */ read_offsetcomp_unit_head84 LONGEST read_offset (bfd *abfd, const gdb_byte *buf, 85 unsigned int *bytes_read) const 86 { 87 LONGEST offset = ::read_offset (abfd, buf, offset_size); 88 *bytes_read = offset_size; 89 return offset; 90 } 91 92 /* Read an address from BUF. BYTES_READ is updated. */ 93 CORE_ADDR read_address (bfd *abfd, const gdb_byte *buf, 94 unsigned int *bytes_read) const; 95 }; 96 97 /* Expected enum dwarf_unit_type for read_comp_unit_head. */ 98 enum class rcuh_kind { COMPILE, TYPE }; 99 100 /* Read in the comp unit header information from the debug_info at info_ptr. 101 Use rcuh_kind::COMPILE as the default type if not known by the caller. 102 NOTE: This leaves members offset, first_die_offset to be filled in 103 by the caller. */ 104 extern const gdb_byte *read_comp_unit_head 105 (struct comp_unit_head *cu_header, 106 const gdb_byte *info_ptr, 107 struct dwarf2_section_info *section, 108 rcuh_kind section_kind); 109 110 /* Read in a CU/TU header and perform some basic error checking. 111 The contents of the header are stored in HEADER. 112 The result is a pointer to the start of the first DIE. */ 113 extern const gdb_byte *read_and_check_comp_unit_head 114 (dwarf2_per_objfile *per_objfile, 115 struct comp_unit_head *header, 116 struct dwarf2_section_info *section, 117 struct dwarf2_section_info *abbrev_section, 118 const gdb_byte *info_ptr, 119 rcuh_kind section_kind); 120 121 #endif /* GDB_DWARF2_COMP_UNIT_H */ 122