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author | Ulrich Drepper <drepper@redhat.com> | 2005-07-26 05:00:05 +0000 |
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committer | Ulrich Drepper <drepper@redhat.com> | 2005-07-26 05:00:05 +0000 |
commit | b08d5a8fb42f4586d756068065186b5af7e48dad (patch) | |
tree | 9f05f86be7877ed461b4dc05f53b29ea4fc0d2a1 /libdw/dwarf_nextcu.c | |
download | elfutils-b08d5a8fb42f4586d756068065186b5af7e48dad.tar.gz |
Adjust for monotone.
Diffstat (limited to 'libdw/dwarf_nextcu.c')
-rw-r--r-- | libdw/dwarf_nextcu.c | 132 |
1 files changed, 132 insertions, 0 deletions
diff --git a/libdw/dwarf_nextcu.c b/libdw/dwarf_nextcu.c new file mode 100644 index 00000000..9dc7633e --- /dev/null +++ b/libdw/dwarf_nextcu.c @@ -0,0 +1,132 @@ +/* Advance to next CU header. + Copyright (C) 2002, 2003, 2004, 2005 Red Hat, Inc. + Written by Ulrich Drepper <drepper@redhat.com>, 2002. + + This program is Open Source software; you can redistribute it and/or + modify it under the terms of the Open Software License version 1.0 as + published by the Open Source Initiative. + + You should have received a copy of the Open Software License along + with this program; if not, you may obtain a copy of the Open Software + License version 1.0 from http://www.opensource.org/licenses/osl.php or + by writing the Open Source Initiative c/o Lawrence Rosen, Esq., + 3001 King Ranch Road, Ukiah, CA 95482. */ + +#ifdef HAVE_CONFIG_H +# include <config.h> +#endif + +#include <libdwP.h> + + +int +dwarf_nextcu (dwarf, off, next_off, header_sizep, abbrev_offsetp, + address_sizep, offset_sizep) + Dwarf *dwarf; + Dwarf_Off off; + Dwarf_Off *next_off; + size_t *header_sizep; + Dwarf_Off *abbrev_offsetp; + uint8_t *address_sizep; + uint8_t *offset_sizep; +{ + /* Maybe there has been an error before. */ + if (dwarf == NULL) + return -1; + + /* If we reached the end before don't do anything. */ + if (off == (Dwarf_Off) -1l + /* Make sure there is enough space in the .debug_info section + for at least the initial word. We cannot test the rest since + we don't know yet whether this is a 64-bit object or not. */ + || unlikely (off + 4 >= dwarf->sectiondata[IDX_debug_info]->d_size)) + { + *next_off = (Dwarf_Off) -1l; + return 1; + } + + /* This points into the .debug_info section to the beginning of the + CU entry. */ + char *bytes = (char *) dwarf->sectiondata[IDX_debug_info]->d_buf + off; + + /* The format of the CU header is described in dwarf2p1 7.5.1: + + 1. A 4-byte or 12-byte unsigned integer representing the length + of the .debug_info contribution for that compilation unit, not + including the length field itself. In the 32-bit DWARF format, + this is a 4-byte unsigned integer (which must be less than + 0xffffff00); in the 64-bit DWARF format, this consists of the + 4-byte value 0xffffffff followed by an 8-byte unsigned integer + that gives the actual length (see Section 7.4). + + 2. A 2-byte unsigned integer representing the version of the + DWARF information for that compilation unit. For DWARF Version + 2.1, the value in this field is 2. + + 3. A 4-byte or 8-byte unsigned offset into the .debug_abbrev + section. This offset associates the compilation unit with a + particular set of debugging information entry abbreviations. In + the 32-bit DWARF format, this is a 4-byte unsigned length; in + the 64-bit DWARF format, this is an 8-byte unsigned length (see + Section 7.4). + + 4. A 1-byte unsigned integer representing the size in bytes of + an address on the target architecture. If the system uses + segmented addressing, this value represents the size of the + offset portion of an address. */ + uint64_t length = read_4ubyte_unaligned_inc (dwarf, bytes); + size_t offset_size = 4; + if (length == 0xffffffffu) + offset_size = 8; + + /* Now we know how large the header is. Note the trick in the + computation. If the offset_size is 4 the '- 4' term undoes the + '2 *'. If offset_size is 8 this term computes the size of the + escape value plus the 8 byte offset. */ + if (unlikely (off + 2 * offset_size - 4 + sizeof (uint16_t) + + offset_size + sizeof (uint8_t) + >= dwarf->sectiondata[IDX_debug_info]->d_size)) + { + *next_off = -1; + return 1; + } + + if (length == 0xffffffffu) + /* This is a 64-bit DWARF format. */ + length = read_8ubyte_unaligned_inc (dwarf, bytes); + + /* Read the version stamp. Always a 16-bit value. + XXX Do we need the value? */ + read_2ubyte_unaligned_inc (dwarf, bytes); + + /* Get offset in .debug_abbrev. Note that the size of the entry + depends on whether this is a 32-bit or 64-bit DWARF definition. */ + uint64_t abbrev_offset; + if (offset_size == 4) + abbrev_offset = read_4ubyte_unaligned_inc (dwarf, bytes); + else + abbrev_offset = read_8ubyte_unaligned_inc (dwarf, bytes); + if (abbrev_offsetp != NULL) + *abbrev_offsetp = abbrev_offset; + + /* The address size. Always an 8-bit value. */ + uint8_t address_size = *bytes++; + if (address_sizep != NULL) + *address_sizep = address_size; + + /* Store the offset size. */ + if (offset_sizep != NULL) + *offset_sizep = offset_size; + + /* Store the header length. */ + if (header_sizep != NULL) + *header_sizep = (bytes + - ((char *) dwarf->sectiondata[IDX_debug_info]->d_buf + + off)); + + /* See above for an explanation of the trick in this formula. */ + *next_off = off + 2 * offset_size - 4 + length; + + return 0; +} +INTDEF(dwarf_nextcu) |