157 lines
5.2 KiB
C
157 lines
5.2 KiB
C
/* Low-level DWARF 2 reading code
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Copyright (C) 1994-2022 Free Software Foundation, Inc.
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Adapted by Gary Funck (gary@intrepid.com), Intrepid Technology,
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Inc. with support from Florida State University (under contract
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with the Ada Joint Program Office), and Silicon Graphics, Inc.
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Initial contribution by Brent Benson, Harris Computer Systems, Inc.,
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based on Fred Fish's (Cygnus Support) implementation of DWARF 1
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support.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#ifndef GDB_DWARF2_LEB_H
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#define GDB_DWARF2_LEB_H
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/* Read dwarf information from a buffer. */
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static inline unsigned int
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read_1_byte (bfd *abfd, const gdb_byte *buf)
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{
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return bfd_get_8 (abfd, buf);
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}
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static inline int
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read_1_signed_byte (bfd *abfd, const gdb_byte *buf)
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{
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return bfd_get_signed_8 (abfd, buf);
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}
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static inline unsigned int
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read_2_bytes (bfd *abfd, const gdb_byte *buf)
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{
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return bfd_get_16 (abfd, buf);
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}
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static inline int
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read_2_signed_bytes (bfd *abfd, const gdb_byte *buf)
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{
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return bfd_get_signed_16 (abfd, buf);
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}
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/* Read the next three bytes (little-endian order) as an unsigned integer. */
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static inline unsigned int
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read_3_bytes (bfd *abfd, const gdb_byte *buf)
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{
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return bfd_get_24 (abfd, buf);
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}
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static inline unsigned int
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read_4_bytes (bfd *abfd, const gdb_byte *buf)
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{
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return bfd_get_32 (abfd, buf);
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}
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static inline int
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read_4_signed_bytes (bfd *abfd, const gdb_byte *buf)
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{
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return bfd_get_signed_32 (abfd, buf);
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}
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static inline ULONGEST
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read_8_bytes (bfd *abfd, const gdb_byte *buf)
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{
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return bfd_get_64 (abfd, buf);
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}
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extern LONGEST read_signed_leb128 (bfd *, const gdb_byte *, unsigned int *);
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extern ULONGEST read_unsigned_leb128 (bfd *, const gdb_byte *, unsigned int *);
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/* Read the initial length from a section. The (draft) DWARF 3
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specification allows the initial length to take up either 4 bytes
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or 12 bytes. If the first 4 bytes are 0xffffffff, then the next 8
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bytes describe the length and all offsets will be 8 bytes in length
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instead of 4.
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An older, non-standard 64-bit format is also handled by this
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function. The older format in question stores the initial length
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as an 8-byte quantity without an escape value. Lengths greater
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than 2^32 aren't very common which means that the initial 4 bytes
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is almost always zero. Since a length value of zero doesn't make
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sense for the 32-bit format, this initial zero can be considered to
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be an escape value which indicates the presence of the older 64-bit
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format. As written, the code can't detect (old format) lengths
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greater than 4GB. If it becomes necessary to handle lengths
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somewhat larger than 4GB, we could allow other small values (such
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as the non-sensical values of 1, 2, and 3) to also be used as
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escape values indicating the presence of the old format.
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The value returned via bytes_read should be used to increment the
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relevant pointer after calling read_initial_length().
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[ Note: read_initial_length() and read_offset() are based on the
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document entitled "DWARF Debugging Information Format", revision
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3, draft 8, dated November 19, 2001. This document was obtained
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from:
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http://reality.sgiweb.org/davea/dwarf3-draft8-011125.pdf
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This document is only a draft and is subject to change. (So beware.)
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Details regarding the older, non-standard 64-bit format were
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determined empirically by examining 64-bit ELF files produced by
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the SGI toolchain on an IRIX 6.5 machine.
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- Kevin, July 16, 2002
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] */
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extern LONGEST read_initial_length (bfd *abfd, const gdb_byte *buf,
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unsigned int *bytes_read,
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bool handle_nonstd = true);
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/* Read an offset from the data stream. */
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extern LONGEST read_offset (bfd *abfd, const gdb_byte *buf,
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unsigned int offset_size);
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static inline const gdb_byte *
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read_n_bytes (bfd *abfd, const gdb_byte *buf, unsigned int size)
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{
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/* If the size of a host char is 8 bits, we can return a pointer
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to the buffer, otherwise we have to copy the data to a buffer
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allocated on the temporary obstack. */
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gdb_assert (HOST_CHAR_BIT == 8);
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return buf;
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}
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static inline const char *
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read_direct_string (bfd *abfd, const gdb_byte *buf,
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unsigned int *bytes_read_ptr)
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{
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/* If the size of a host char is 8 bits, we can return a pointer
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to the string, otherwise we have to copy the string to a buffer
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allocated on the temporary obstack. */
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gdb_assert (HOST_CHAR_BIT == 8);
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if (*buf == '\0')
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{
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*bytes_read_ptr = 1;
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return NULL;
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}
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*bytes_read_ptr = strlen ((const char *) buf) + 1;
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return (const char *) buf;
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}
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#endif /* GDB_DWARF2_LEB_H */
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