NAME
dwarf_get_abbrev —
retrieve
abbreviation information
LIBRARY
DWARF Access Library (libdwarf, -ldwarf)
SYNOPSIS
#include <libdwarf.h>
int
dwarf_get_abbrev(
Dwarf_Debug dbg,
Dwarf_Unsigned offset,
Dwarf_Abbrev
*ret_abbrev,
Dwarf_Unsigned *length,
Dwarf_Unsigned *attr_count,
Dwarf_Error
*err);
DESCRIPTION
Function
dwarf_get_abbrev() retrieves information about an
abbreviation from the DWARF abbreviations section,
“.debug_abbrev”. Abbreviation information is returned using an
opaque descriptor of type
Dwarf_Abbrev. The returned
Dwarf_Abbrev descriptor may then be passed to the other
abbreviation related APIs in the DWARF(3) API to retrieve specific information
about the abbreviation.
Argument
dbg should reference a DWARF debug context
allocated using
dwarf_init(3).
Argument
offset should be an offset, relative to the
“.debug_abbrev” section, to the start of an abbreviation entry.
Argument
ret_abbrev should point to a location that will
hold a pointer to the returned
Dwarf_Abbrev descriptor.
Argument
length should point to a location that will hold
the number of bytes used by the abbrevation in the DWARF
“.debug_abbrev” section.
Argument
attr_count should point to a location that will
hold the number of attributes in the abbrevation.
If argument
err is not NULL, it will be used to store
error information in case of an error.
Memory Management
The memory area used for the
Dwarf_Abbrev descriptor
returned in argument
ret_abbrev is allocated by the
DWARF Access Library (libdwarf, -ldwarf). Application
code should use function
dwarf_dealloc() with the allocation
type
DW_DLA_ABBREV
to free the memory area when the
Dwarf_Abbrev descriptor is no longer needed.
Application Programming
Notes
The last abbreviation entry in a standard DWARF abbreviation section will have a
special length value of 1.
RETURN VALUES
Function
dwarf_get_abbrev() returns
DW_DLV_OK
when it succeeds. It returns
DW_DLV_NO_ENTRY
if there is no abbreviation
information at offset
offset. In case of an error, it
returns
DW_DLV_ERROR
and sets the argument
err.
ERRORS
Function
dwarf_get_abbrev() can fail with:
-
-
- [
DW_DLE_ARGUMENT
]
- One of the arguments dbg,
ret_abbrev, length or
attr_count was NULL.
-
-
- [
DW_DLE_NO_ENTRY
]
- There is no abbreviation information at offset
offset.
EXAMPLE
To loop through all the abbreviation information associated with a DWARF debug
context, use:
Dwarf_Debug dbg;
Dwarf_Abbrev ab;
Dwarf_Off aboff;
Dwarf_Unsigned length, attr_count;
Dwarf_Half tag;
Dwarf_Error de;
int ret;
while ((ret = dwarf_next_cu_header(dbg, NULL, NULL, &aboff,
NULL, NULL, &de)) == DW_DLV_OK) {
while ((ret = dwarf_get_abbrev(re->dbg, aboff, &ab, &length,
&attr_count, &de)) == DW_DLV_OK) {
if (length == 1) /* Last entry. */
break;
aboff += length;
if (dwarf_get_abbrev_tag(ab, &tag, &de) != DW_DLV_OK) {
warnx("dwarf_get_abbrev_tag failed: %s",
dwarf_errmsg(de));
continue;
}
if (ret != DW_DLV_OK)
warnx("dwarf_get_abbrev: %s", dwarf_errmsg(de));
}
if (ret == DW_DLV_ERROR)
warnx("dwarf_next_cu_header: %s", dwarf_errmsg(de));
SEE ALSO
dwarf(3),
dwarf_dealloc(3),
dwarf_get_abbrev_tag(3),
dwarf_get_abbrev_code(3),
dwarf_get_abbrev_children_flag(3),
dwarf_get_abbrev_entry(3)