dwarf_get_abbrev —
retrieve abbreviation information
DWARF Access Library (libdwarf, -ldwarf)
#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);
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.
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.
The last abbreviation entry in a standard DWARF abbreviation section will have a
special length value of 1.
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.
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));
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.
dwarf(3),
dwarf_dealloc(3),
dwarf_get_abbrev_children_flag(3),
dwarf_get_abbrev_code(3),
dwarf_get_abbrev_entry(3),
dwarf_get_abbrev_tag(3)