gdb: IPA Protocol Objects
30.1.1 IPA Protocol Objects
---------------------------
The commands sent to and results received from agent may contain some
complex data types called "objects".
The in-process agent is running on the same machine with GDB or
GDBserver, so it doesn't have to handle as much differences between two
ends as remote protocol (
Remote Protocol) tries to handle.
However, there are still some differences of two ends in two processes:
1. word size. On some 64-bit machines, GDB or GDBserver can be
compiled as a 64-bit executable, while in-process agent is a 32-bit
one.
2. ABI. Some machines may have multiple types of ABI, GDB or GDBserver
is compiled with one, and in-process agent is compiled with the
other one.
Here are the IPA Protocol Objects:
1. agent expression object. It represents an agent expression (
Agent Expressions).
2. tracepoint action object. It represents a tracepoint action (
Tracepoint Action Lists Tracepoint Actions.) to collect registers,
memory, static trace data and to evaluate expression.
3. tracepoint object. It represents a tracepoint (
Tracepoints).
The following table describes important attributes of each IPA
protocol object:
Name Size Description
---------------------------------------------------------------------------
_agent expression
object_
length 4 length of bytes code
byte code LENGTH contents of byte code
_tracepoint action
for collecting
memory_
'M' 1 type of tracepoint action
addr 8 if BASEREG is '-1', ADDR is the
address of the lowest byte to
collect, otherwise ADDR is the
offset of BASEREG for memory
collecting.
len 8 length of memory for collecting
basereg 4 the register number containing the
starting memory address for
collecting.
_tracepoint action
for collecting
registers_
'R' 1 type of tracepoint action
_tracepoint action
for collecting
static trace data_
'L' 1 type of tracepoint action
_tracepoint action
for expression
evaluation_
'X' 1 type of tracepoint action
agent expression length of agent expression object
_tracepoint object_
number 4 number of tracepoint
address 8 address of tracepoint inserted on
type 4 type of tracepoint
enabled 1 enable or disable of tracepoint
step_count 8 step
pass_count 8 pass
numactions 4 number of tracepoint actions
hit count 8 hit count
trace frame usage 8 trace frame usage
compiled_cond 8 compiled condition
orig_size 8 orig size
condition 4 if zero if condition is NULL,
condition is otherwise is
NULL agent expression object
otherwise
length of
agent expression object
actions variable numactions number of
tracepoint action object
Info Catalog
gdb: In-Process Agent Protocol
gdb: IPA Protocol Commands