Gdb/GDB 002fMI-Program-Execution
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27.13 GDB/MI Program Execution
These are the asynchronous commands which generate the out-of-band
record ‘*stopped
’. Currently GDB only really executes
asynchronously with remote targets and this interaction is mimicked in
other cases.
The -exec-continue
Command
Synopsis
-exec-continue [--reverse] [--all|--thread-group N]
Resumes the execution of the inferior program, which will continue
to execute until it reaches a debugger stop event. If the
‘--reverse
’ option is specified, execution resumes in reverse until
it reaches a stop event. Stop events may include
- breakpoints or watchpoints
- signals or exceptions
- the end of the process (or its beginning under ‘
--reverse
’) - the end or beginning of a replay log if one is being used.
In all-stop mode (see All-Stop Mode), may resume only one thread, or all threads, depending on the
value of the ‘scheduler-locking
’ variable. If ‘--all
’ is
specified, all threads (in all inferiors) will be resumed. The ‘--all
’ option is
ignored in all-stop mode. If the ‘--thread-group
’ options is
specified, then all threads in that thread group are resumed.
GDB Command
The corresponding GDB corresponding is ‘continue
’.
Example
-exec-continue ^running (gdb) @Hello world *stopped,reason="breakpoint-hit",disp="keep",bkptno="2",frame={ func="foo",args=[],file="hello.c",fullname="/home/foo/bar/hello.c", line="13",arch="i386:x86_64"} (gdb)
The -exec-finish
Command
Synopsis
-exec-finish [--reverse]
Resumes the execution of the inferior program until the current
function is exited. Displays the results returned by the function.
If the ‘--reverse
’ option is specified, resumes the reverse
execution of the inferior program until the point where current
function was called.
GDB Command
The corresponding GDB command is ‘finish
’.
Example
Function returning void
.
-exec-finish ^running (gdb) @hello from foo *stopped,reason="function-finished",frame={func="main",args=[], file="hello.c",fullname="/home/foo/bar/hello.c",line="7",arch="i386:x86_64"} (gdb)
Function returning other than void
. The name of the internal
GDB variable storing the result is printed, together with the
value itself.
-exec-finish ^running (gdb) *stopped,reason="function-finished",frame={addr="0x000107b0",func="foo", args=[{name="a",value="1"],{name="b",value="9"}}, file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14", arch="i386:x86_64"}, gdb-result-var="$1",return-value="0" (gdb)
The -exec-interrupt
Command
Synopsis
-exec-interrupt [--all|--thread-group N]
Interrupts the background execution of the target. Note how the token
associated with the stop message is the one for the execution command
that has been interrupted. The token for the interrupt itself only
appears in the ‘^done
’ output. If the user is trying to
interrupt a non-running program, an error message will be printed.
Note that when asynchronous execution is enabled, this command is
asynchronous just like other execution commands. That is, first the
‘^done
’ response will be printed, and the target stop will be
reported after that using the ‘*stopped
’ notification.
In non-stop mode, only the context thread is interrupted by default.
All threads (in all inferiors) will be interrupted if the
‘--all
’ option is specified. If the ‘--thread-group
’
option is specified, all threads in that group will be interrupted.
GDB Command
The corresponding GDB command is ‘interrupt
’.
Example
(gdb) 111-exec-continue 111^running (gdb) 222-exec-interrupt 222^done (gdb) 111*stopped,signal-name="SIGINT",signal-meaning="Interrupt", frame={addr="0x00010140",func="foo",args=[],file="try.c", fullname="/home/foo/bar/try.c",line="13",arch="i386:x86_64"} (gdb) (gdb) -exec-interrupt ^error,msg="mi_cmd_exec_interrupt: Inferior not executing." (gdb)
The -exec-jump
Command
Synopsis
-exec-jump location
Resumes execution of the inferior program at the location specified by
parameter. See Specify Location, for a description of the
different forms of location
.
GDB Command
The corresponding GDB command is ‘jump
’.
Example
-exec-jump foo.c:10 *running,thread-id="all" ^running
The -exec-next
Command
Synopsis
-exec-next [--reverse]
Resumes execution of the inferior program, stopping when the beginning of the next source line is reached.
If the ‘--reverse
’ option is specified, resumes reverse execution
of the inferior program, stopping at the beginning of the previous
source line. If you issue this command on the first line of a
function, it will take you back to the caller of that function, to the
source line where the function was called.
GDB Command
The corresponding GDB command is ‘next
’.
Example
-exec-next ^running (gdb) *stopped,reason="end-stepping-range",line="8",file="hello.c" (gdb)
The -exec-next-instruction
Command
Synopsis
-exec-next-instruction [--reverse]
Executes one machine instruction. If the instruction is a function call, continues until the function returns. If the program stops at an instruction in the middle of a source line, the address will be printed as well.
If the ‘--reverse
’ option is specified, resumes reverse execution
of the inferior program, stopping at the previous instruction. If the
previously executed instruction was a return from another function,
it will continue to execute in reverse until the call to that function
(from the current stack frame) is reached.
GDB Command
The corresponding GDB command is ‘nexti
’.
Example
(gdb) -exec-next-instruction ^running (gdb) *stopped,reason="end-stepping-range", addr="0x000100d4",line="5",file="hello.c" (gdb)
The -exec-return
Command
Synopsis
-exec-return
Makes current function return immediately. Doesn’t execute the inferior. Displays the new current frame.
GDB Command
The corresponding GDB command is ‘return
’.
Example
(gdb) 200-break-insert callee4 200^done,bkpt={number="1",addr="0x00010734", file="../../../devo/gdb/testsuite/gdb.mi/basics.c",line="8"} (gdb) 000-exec-run 000^running (gdb) 000*stopped,reason="breakpoint-hit",disp="keep",bkptno="1", frame={func="callee4",args=[], file="../../../devo/gdb/testsuite/gdb.mi/basics.c", fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="8", arch="i386:x86_64"} (gdb) 205-break-delete 205^done (gdb) 111-exec-return 111^done,frame={level="0",func="callee3", args=[{name="strarg", value="0x11940 \"A string argument.\""}], file="../../../devo/gdb/testsuite/gdb.mi/basics.c", fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="18", arch="i386:x86_64"} (gdb)
The -exec-run
Command
Synopsis
-exec-run [ --all | --thread-group N ] [ --start ]
Starts execution of the inferior from the beginning. The inferior executes until either a breakpoint is encountered or the program exits. In the latter case the output will include an exit code, if the program has exited exceptionally.
When neither the ‘--all
’ nor the ‘--thread-group
’ option
is specified, the current inferior is started. If the
‘--thread-group
’ option is specified, it should refer to a thread
group of type ‘process
’, and that thread group will be started.
If the ‘--all
’ option is specified, then all inferiors will be started.
Using the ‘--start
’ option instructs the debugger to stop
the execution at the start of the inferior’s main subprogram,
following the same behavior as the start
command
(see Starting).
GDB Command
The corresponding GDB command is ‘run
’.
Examples
(gdb) -break-insert main ^done,bkpt={number="1",addr="0x0001072c",file="recursive2.c",line="4"} (gdb) -exec-run ^running (gdb) *stopped,reason="breakpoint-hit",disp="keep",bkptno="1", frame={func="main",args=[],file="recursive2.c", fullname="/home/foo/bar/recursive2.c",line="4",arch="i386:x86_64"} (gdb)
Program exited normally:
(gdb) -exec-run ^running (gdb) x = 55 *stopped,reason="exited-normally" (gdb)
Program exited exceptionally:
(gdb) -exec-run ^running (gdb) x = 55 *stopped,reason="exited",exit-code="01" (gdb)
Another way the program can terminate is if it receives a signal such as
SIGINT
. In this case, GDB/MI displays this:
(gdb) *stopped,reason="exited-signalled",signal-name="SIGINT", signal-meaning="Interrupt"
The -exec-step
Command
Synopsis
-exec-step [--reverse]
Resumes execution of the inferior program, stopping when the beginning
of the next source line is reached, if the next source line is not a
function call. If it is, stop at the first instruction of the called
function. If the ‘--reverse
’ option is specified, resumes reverse
execution of the inferior program, stopping at the beginning of the
previously executed source line.
GDB Command
The corresponding GDB command is ‘step
’.
Example
Stepping into a function:
-exec-step ^running (gdb) *stopped,reason="end-stepping-range", frame={func="foo",args=[{name="a",value="10"}, {name="b",value="0"}],file="recursive2.c", fullname="/home/foo/bar/recursive2.c",line="11",arch="i386:x86_64"} (gdb)
Regular stepping:
-exec-step ^running (gdb) *stopped,reason="end-stepping-range",line="14",file="recursive2.c" (gdb)
The -exec-step-instruction
Command
Synopsis
-exec-step-instruction [--reverse]
Resumes the inferior which executes one machine instruction. If the
‘--reverse
’ option is specified, resumes reverse execution of the
inferior program, stopping at the previously executed instruction.
The output, once GDB has stopped, will vary depending on
whether we have stopped in the middle of a source line or not. In the
former case, the address at which the program stopped will be printed
as well.
GDB Command
The corresponding GDB command is ‘stepi
’.
Example
(gdb) -exec-step-instruction ^running (gdb) *stopped,reason="end-stepping-range", frame={func="foo",args=[],file="try.c", fullname="/home/foo/bar/try.c",line="10",arch="i386:x86_64"} (gdb) -exec-step-instruction ^running (gdb) *stopped,reason="end-stepping-range", frame={addr="0x000100f4",func="foo",args=[],file="try.c", fullname="/home/foo/bar/try.c",line="10",arch="i386:x86_64"} (gdb)
The -exec-until
Command
Synopsis
-exec-until [ location ]
Executes the inferior until the location
specified in the
argument is reached. If there is no argument, the inferior executes
until a source line greater than the current one is reached. The
reason for stopping in this case will be ‘location-reached
’.
GDB Command
The corresponding GDB command is ‘until
’.
Example
(gdb) -exec-until recursive2.c:6 ^running (gdb) x = 55 *stopped,reason="location-reached",frame={func="main",args=[], file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="6", arch="i386:x86_64"} (gdb)
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