dwarf_next_cu_header,
dwarf_next_cu_header_b,
dwarf_next_cu_header_c —
step through compilation units in a DWARF debug
context
DWARF Access Library (libdwarf, -ldwarf)
#include
<libdwarf.h>
int
dwarf_next_cu_header(
Dwarf_Debug
dbg,
Dwarf_Unsigned *cu_length,
Dwarf_Half *cu_version,
Dwarf_Off *cu_abbrev_offset,
Dwarf_Half *cu_pointer_size,
Dwarf_Unsigned *cu_next_offset,
Dwarf_Error *err);
int
dwarf_next_cu_header_b(
Dwarf_Debug
dbg,
Dwarf_Unsigned *cu_length,
Dwarf_Half *cu_version,
Dwarf_Off *cu_abbrev_offset,
Dwarf_Half *cu_pointer_size,
Dwarf_Half *cu_offset_size,
Dwarf_Half *cu_extension_size,
Dwarf_Unsigned *cu_next_offset,
Dwarf_Error *err);
int
dwarf_next_cu_header_c(
Dwarf_Debug
dbg,
Dwarf_Bool is_info,
Dwarf_Unsigned *cu_length,
Dwarf_Half *cu_version,
Dwarf_Off *cu_abbrev_offset,
Dwarf_Half *cu_pointer_size,
Dwarf_Half *cu_offset_size,
Dwarf_Half *cu_extension_size,
Dwarf_Sig8 *type_signature,
Dwarf_Unsigned *type_offset,
Dwarf_Unsigned *cu_next_offset,
Dwarf_Error *err);
These functions are used to step through compilation or type units associated
with a DWARF debug context, optionally returning information about the unit.
Function
dwarf_next_cu_header_c() is the API
recommended for new application code. Function
dwarf_next_cu_header() and
dwarf_next_cu_header_b() can only operate on
compilation units associated with the “.debug_info” section.
They are less general than function
dwarf_next_cu_header_c(), and are deprecated for
use by new application code.
Argument
dbg should reference a DWARF debug
context allocated using
dwarf_init(3). If
argument
is_info is set to 1, the function
returns information for compilation units found in the
“.debug_info” section. If argument
is_info is set to 0, the function returns
information for type units found in the “.debug_types” sections.
Argument
cu_length should point to a location
that will be set to the length of the compilation or type unit. Argument
cu_version should point to a location that
will be set to the version number for the compilation or type unit. Argument
cu_abbrev_offset should point to a location
that will be set to the starting offset (in the “.debug_abbrev”
section) of the set of debugging information entry abbreviations associated
with this compilation or type unit. Argument
cu_pointer_size should point to a location
that will be set to the size in bytes of an address for the machine
architecture of the underlying object being debugged. Argument
cu_offset_size should point to a location
that will be set to the size in bytes for a DWARF offset in the compilation or
type unit. Argument
cu_extension_size is only
needed for processing MIPS/IRIX objects that use a non-standard DWARF format.
It should point to a location that will be set to 4 for normal objects and to
0 for non-standard ones. Argument
type_signature and
type_offset is only needed for processing
type units. Argument
type_signature should
point to a location that will be set to the 64-bit unique signature of the
type described in the type unit. Argument
type_offset should point to a location that
will be set to the offset of the debugging information entry that describes
the type. Argument
cu_next_offset should
point to a location that will be set to the offset of the next compilation
unit header in the “.debug_info” section, or the offset of the
next type unit header in the “.debug_types” section. Argument
err should point to a location that will hold
an error descriptor in case of an error.
Function
dwarf_next_cu_header_b() is identical to
function
dwarf_next_cu_header_c() except that it
does not provide arguments
is_info,
type_signature and
type_offset.
Function
dwarf_next_cu_header() is identical to
function
dwarf_next_cu_header_b() except that it
does not provide arguments
cu_offset_size and
cu_extension_size.
A value of NULL may be used for any of the arguments
cu_length,
cu_version,
cu_abbrev_offset,
cu_pointer_size,
cu_offset_size,
cu_extension_size,
type_signature,
type_offset,
cu_next_offset and
err if the caller is not interested in the
respective value.
The first call to function
dwarf_next_cu_header_c()
for a given debug context with argument
is_info set to 1 will return information
about the first compilation unit in the “.debug_info” section.
Subsequent calls to the function will iterate through the remaining
compilation units in the section. On stepping past the last compilation unit
in the section, function
dwarf_next_cu_header_c()
returns
DW_DLV_NO_ENTRY
and resets its
internal state. The next call to the function will restart from the first
compilation unit in the section.
When a DWARF debug context is allocated using
dwarf_init(3), an
internal pointer associated with the context will point to the first
“.debug_types” section found in the debug object. The first call
to function
dwarf_next_cu_header_c() for the
debug context with argument
is_info set to 0
will return information about the first type unit in that
“.debug_types” section. Subsequent calls to the function will
iterate through the remaining type units in the section. On stepping past the
last type unit in the debug context, function
dwarf_next_cu_header_c() returns
DW_DLV_NO_ENTRY
and resets its internal
state. The next call to the function will restart from the first type unit in
the “.debug_types” section.
If the debug object contains multiple “.debug_types” sections, the
function
dwarf_next_types_section() can be called
to move the internal pointer to the next “.debug_types” section.
As a result, subsequent calls of the function
dwarf_next_cu_header_c() will operate on the new
“.debug_types” section. Function
dwarf_next_types_section() returns
DW_DLV_NO_ENTRY
when there are no more
“.debug_types” sections left in the debug object.
On success, these functions return
DW_DLV_OK
.
In case of an error, they return
DW_DLV_ERROR
and set argument
err. When there are no more compilation units
left to traverse, they return
DW_DLV_NO_ENTRY
.
These functions can fail with the following error:
-
-
- [
DW_DLE_ARGUMENT
]
- Argument dbg was
NULL.
dwarf(3),
dwarf_get_cu_die_offset_given_cu_header_offset(3),
dwarf_init(3),
dwarf_next_types_section(3),
dwarf_siblingof(3)