Re: [patch] circ.exp

Pedro Alves
2013-04-18T17:04:44Z

Hi,

On 04/18/2013 04:39 PM, Abid, Hafiz wrote:

> diff --git a/gdb/testsuite/gdb.trace/circ.exp b/gdb/testsuite/gdb.trace/circ.exp
> index 4c47228..c2d1575 100644
> --- a/gdb/testsuite/gdb.trace/circ.exp
> +++ b/gdb/testsuite/gdb.trace/circ.exp
> @@ -15,7 +15,6 @@
>
> load_lib "trace-support.exp"
>
> -
> standard_testfile
>
> if {[prepare_for_testing $testfile.exp $testfile $srcfile {debug nowarnings}]} {
> @@ -23,194 +22,232 @@ if {[prepare_for_testing $testfile.exp $testfile $srcfile {debug nowarnings}]} {
> }
>
> # Tests:
> -# 1) Set up a trace experiment that will collect approximately 10 frames,
> +# 1) Calculate the size taken by one trace frame.
> +# 2) Set up a trace experiment that will collect approximately 10 frames,
> # requiring more than 512 but less than 1024 bytes of cache buffer.
> # (most targets should have at least 1024 bytes of cache buffer!)
> # Run and confirm that it collects all 10 frames.
> -# 2) Artificially limit the trace buffer to 512 bytes, and rerun the
> -# experiment. Confirm that the first several frames are collected,
> -# but that the last several are not.
> -# 3) Set trace buffer to circular mode, still with the artificial limit
> -# of 512 bytes, and rerun the experiment. Confirm that the last
> -# several frames are collected, but the first several are not.
> +# 3) Artificially limit the trace buffer to 4x + a bytes. Here x is the size
> +# of single trace frame and a is a small constant. Rerun the
> +# experiment. Confirm that the frame for the first tracepoint is collected,
> +# but frames for the last several tracepoints are not.
> +# 4) Set trace buffer to circular mode, with the size buffer size as in

s/size buffer size/buffer size/

> +# step 3 above. Rerun the experiment. Confirm that the frame for the last
> +# tracepoint is collected but not for the first one.
> #
>
> -# return 0 for success, 1 for failure
> -proc run_trace_experiment { pass } {
> - gdb_run_cmd
> -
> - if [gdb_test "tstart" \
> - "\[\r\n\]*" \
> - "start trace experiment, pass $pass"] then { return 1 }
> - if [gdb_test "continue" \
> - "Continuing.*Breakpoint \[0-9\]+, end.*" \
> - "run to end, pass $pass"] then { return 1 }
> - if [gdb_test "tstop" \
> - "\[\r\n\]*" \
> - "stop trace experiment, pass $pass"] then { return 1 }
> - return 0
> +# Set a tracepoint on given func. Return 0 for success,
> +# 1 for failure.
> +proc set_a_tracepoint { func } {
> + gdb_test "trace $func" "Tracepoint \[0-9\]+ at .*" \
> + "set tracepoint at $func"
> + gdb_trace_setactions "set actions for $func" "" "collect testload" "^$"
> }
>
> -# return 0 for success, 1 for failure
> -proc set_a_tracepoint { func } {
> - if [gdb_test "trace $func" \
> - "Tracepoint \[0-9\]+ at .*" \
> - "set tracepoint at $func"] then {
> +# Sets the tracepoints from func0 to func9 using
> +# set_a_tracepoint. Return 0 for success, 1 for failure.
> +proc setup_tracepoints { } {
> + gdb_delete_tracepoints
> + set_a_tracepoint func0
> + set_a_tracepoint func1
> + set_a_tracepoint func2
> + set_a_tracepoint func3
> + set_a_tracepoint func4
> + set_a_tracepoint func5
> + set_a_tracepoint func6
> + set_a_tracepoint func7
> + set_a_tracepoint func8
> + set_a_tracepoint func9

> +if [gdb_test "tstatus" ".*Trace buffer is circular.*" \
> + "circular buffer is supported"] {
> + unsupported "target does not support circular trace buffer"

This issues a FAIL in the unsupported case. We need to instead
use gdb_test_multiple to prevent that. E.g.,

set circular_supported -1
set test "check whether circular buffer is supported"
gdb_test_multiple "tstatus" $test {
-re ".*Trace buffer is circular.*$gdb_prompt $" {
pass $test
}
-re "$gdb_prompt $" {
pass $test
}
}

if { $circular_supported < 0 } {
unsupported "target does not support circular trace buffer"
return 1
}

Please disable circular tracing support in your gdbserver (e.g.,
hack handle_tracepoint_general_set) and make sure the file
tests without FAILs.

> return 1
> - }
> - if [gdb_trace_setactions "set actions for $func" \
> - "" \
> - "collect testload" "^$"] then {
> +}
> +
> +# Check if changing trace buffer size is supported. This step is
> +# repeated twice. This helps in case if trace buffer size is 100.
> +set test_size 100
> +gdb_test_no_output "set trace-buffer-size $test_size" \
> + "change buffer size to $test_size"
> +
> +if [gdb_test "tstatus" \
> + ".*Trace buffer has $decimal bytes of $test_size bytes free.*" \
> + "buffer size is $test_size"] {
> + unsupported "target does not support changing trace buffer size"
> return 1
> - }
> - return 0
> }

Likewise, disable buffer size support, and make sure this doesn't
issue a FAIL.

>
> -# return 0 for success, 1 for failure
> -proc setup_tracepoints { } {
> - gdb_delete_tracepoints
> - if [set_a_tracepoint func0] then { return 1 }
> - if [set_a_tracepoint func1] then { return 1 }
> - if [set_a_tracepoint func2] then { return 1 }
> - if [set_a_tracepoint func3] then { return 1 }
> - if [set_a_tracepoint func4] then { return 1 }
> - if [set_a_tracepoint func5] then { return 1 }
> - if [set_a_tracepoint func6] then { return 1 }
> - if [set_a_tracepoint func7] then { return 1 }
> - if [set_a_tracepoint func8] then { return 1 }
> - if [set_a_tracepoint func9] then { return 1 }
> - return 0
> +set test_size 200
> +gdb_test_no_output "set trace-buffer-size $test_size" \
> + "change buffer size to $test_size"
> +
> +if [gdb_test "tstatus" \
> + ".*Trace buffer has $decimal bytes of $test_size bytes free.*" \
> + "buffer size is $test_size"] {
> + unsupported "target does not support changing trace buffer size"
> + return 1
> }

Likewise.

>
> -# return 0 for success, 1 for failure
> -proc trace_buffer_normal { } {
> - global gdb_prompt
> +gdb_test_no_output "set circular-trace-buffer off" \
> + "set circular-trace-buffer off"
> +
> +gdb_test "show circular-trace-buffer" \
> + "Target's use of circular trace buffer is off." \
> + "show circular-trace-buffer (off)"
> +
> +set total_size -1
> +set free_size -1
> +set frame_size -1
>
> - set ok 0
> - set test "maint packet QTBuffer:size:ffffffff"
> - gdb_test_multiple $test $test {
> - -re "received: .OK.\r\n$gdb_prompt $" {
> - set ok 1
> +# Determine the size used by a single frame. Put single tracepoint,
> +# run and then check the total and free size using tstatus command.

"Set a single tracepoint, " ... "using the tstatus command".

> +# Then subtracting free from total gives us the size of a frame.
> +with_test_prefix "frame size" {
> + set_a_tracepoint func0
> +
> + gdb_test "break end" "Breakpoint $decimal.*" "breakpoint at end"
> +
> + gdb_test "tstart" "\[\r\n\]*" "start trace"
> +
> + gdb_test "continue" "Continuing.*Breakpoint \[0-9\]+, end.*" \
> + "run to end"
> +
> + gdb_test "tstop" "\[\r\n\]*" "stop trace"
> +
> + set test "get buffer size"
> +
> + gdb_test_multiple "tstatus" $test {
> + -re ".*Trace buffer has ($decimal) bytes of ($decimal) bytes free.*$gdb_prompt $" {
> + set free_size $expect_out(1,string)
> + set total_size $expect_out(2,string)
> pass $test
> }
> - -re "\r\n$gdb_prompt $" {
> - }
> }
> - if { !$ok } {
> - unsupported $test
> +
> + # Check that we get the total_size and free_size
> + if { $total_size < 0 } {
> return 1
> }
>
> - set ok 0
> - set test "maint packet QTBuffer:circular:0"
> - gdb_test_multiple $test $test {
> - -re "received: .OK.\r\n$gdb_prompt $" {
> - set ok 1
> - pass $test
> - }
> - -re "\r\n$gdb_prompt $" {
> - }
> - }
> - if { !$ok } {
> - unsupported $test
> + if { $free_size < 0 } {
> return 1
> }
> -
> - return 0
> }
>
> -# return 0 for success, 1 for failure
> -proc gdb_trace_circular_tests { } {
> - if { ![gdb_target_supports_trace] } then {
> - unsupported "Current target does not support trace"
> +# Calculate the size of a single frame
> +set frame_size "($total_size - $free_size)"
> +
> +with_test_prefix "normal buffer" {
> + clean_restart $testfile
> +
> + if { ![runto_main] } {
> + fail "can't run to main"
> return 1
> }
>
> - if [trace_buffer_normal] then { return 1 }
> -
> - gdb_test "break begin" ".*" ""
> - gdb_test "break end" ".*" ""
> - gdb_test "tstop" ".*" ""
> - gdb_test "tfind none" ".*" ""
> + run_trace_experiment
>
> - if [setup_tracepoints] then { return 1 }
> + # Check that frame 0 is actually at func0.

s/frame 0/the first frame/

> + gdb_test "tfind start" ".*#0 func0 .*" \
> + "find first frame"
>
> - # First, run the trace experiment with default attributes:
> - # Make sure it behaves as expected.
> - if [run_trace_experiment 1] then { return 1 }
> - if [gdb_test "tfind start" \
> - "#0 func0 .*" \
> - "find frame zero, pass 1"] then { return 1 }
> + gdb_test "tfind tracepoint 9" \
> + ".*Found trace frame $decimal, tracepoint 9.*" \
> + "find frame for tracepoint 9"

Sorry, this isn't right yet. The number space of tracepoints is
shared with breakpoints. It didn't used to be that way up until a couple of
years ago. So the tracepoint at func9 is not actually tracepoint 9 -- it
depends on the number of breakpoints the test has setup before creating
the tracepoints.

(gdb) PASS: gdb.trace/circ.exp: show circular-trace-buffer (off)
trace func0
Tracepoint 2 at 0x400540: file ../../../src/gdb/testsuite/gdb.trace/circ.c, line 28.
(gdb) PASS: gdb.trace/circ.exp: frame size: set tracepoint at func0
...
(gdb) PASS: gdb.trace/circ.exp: normal buffer: set actions for func8
trace func9
Tracepoint 11 at 0x400576: file ../../../src/gdb/testsuite/gdb.trace/circ.c, line 64.
(gdb) PASS: gdb.trace/circ.exp: normal buffer: set tracepoint at func9

Hardcoding a number is fragile. The test may change in the future, or the
dejagnu board file itself may create breakpoints. We could either
ask GDB for the tracepoint number (it's in $tpnum), or
use "tfind pc func9".

> +}
>
> - if [gdb_test "tfind 9" \
> - "#0 func9 .*" \
> - "find frame nine, pass 1"] then { return 1 }
> +# Shrink the trace buffer so that it will not hold
> +# all ten trace frames. Verify that frame zero is still

s/frame zero/somethingelse/. "that a frame for func0"

> +# collected, but frame nine is not.

likewise for frame nine.

>
> - if [gdb_test "tfind none" \
> - "#0 end .*" \
> - "quit trace debugging, pass 1"] then { return 1 }
> +set buffer_size "((4 * $frame_size) + 10)"
> +with_test_prefix "small buffer" {
> + clean_restart $testfile
>
> - # Then, shrink the trace buffer so that it will not hold
> - # all ten trace frames. Verify that frame zero is still
> - # collected, but frame nine is not.
> - if [gdb_test "maint packet QTBuffer:size:200" \
> - "received: .OK." "shrink the target trace buffer"] then {
> - return 1
> - }
> - if [run_trace_experiment 2] then { return 1 }
> - if [gdb_test "tfind start" \
> - "#0 func0 .*" \
> - "find frame zero, pass 2"] then { return 1 }
> -
> - if [gdb_test "tfind 9" \
> - ".* failed to find .*" \
> - "fail to find frame nine, pass 2"] then { return 1 }
> -
> - if [gdb_test "tfind none" \
> - "#0 end .*" \
> - "quit trace debugging, pass 2"] then { return 1 }
> -
> - # Finally, make the buffer circular. Now when it runs out of
> - # space, it should wrap around and overwrite the earliest frames.
> - # This means that:
> - # 1) frame zero will be overwritten and therefore unavailable
> - # 2) the earliest frame in the buffer will be other-than-zero
> - # 3) frame nine will be available (unlike on pass 2).
> - if [gdb_test "maint packet QTBuffer:circular:1" \
> - "received: .OK." "make the target trace buffer circular"] then {
> + if { ![runto_main] } {
> + fail "can't run to main"
> return 1
> }
> - if [run_trace_experiment 3] then { return 1 }
> - if [gdb_test "tfind start" \
> - "#0 func\[1-9\] .*" \
> - "first frame is NOT frame zero, pass 3"] then { return 1 }
>
> - if [gdb_test "tfind 9" \
> - "#0 func9 .*" \
> - "find frame nine, pass 3"] then { return 1 }
> + gdb_test_no_output "set trace-buffer-size $buffer_size" \
> + "shrink the target trace buffer"
> +
> + run_trace_experiment
>
> - if [gdb_test "tfind none" \
> - "#0 end .*" \
> - "quit trace debugging, pass 3"] then { return 1 }
> + gdb_test "tfind start" ".*#0 func0 .*" \
> + "find first frame"
>
> - return 0
> + gdb_test "tfind none" ".*"
> +
> + gdb_test "tfind tracepoint 9" ".* failed to find .*" \
> + "find frame for tracepoint 9";
> }
>
> -gdb_test_no_output "set circular-trace-buffer on" \
> - "set circular-trace-buffer on"
> +# Finally, make the buffer circular. Now when it runs out of
> +# space, it should wrap around and overwrite the earliest frames.
> +# This means that:
> +# 1) frame zero will be overwritten and therefore unavailable

"frame zero" here.

> +# 2) the earliest frame in the buffer will be for a tracepoint other than 1
> +# 3) the frame for tracepoint 9 will be available (unlike "small buffer" case).
> +with_test_prefix "circular buffer" {
> + clean_restart $testfile
> +
> + if { ![runto_main] } {
> + fail "can't run to main"
> + return 1
> + }
>
> -gdb_test "show circular-trace-buffer" "Target's use of circular trace buffer is on." "show circular-trace-buffer (on)"
> + gdb_test_no_output "set trace-buffer-size $buffer_size" \
> + "shrink the target trace buffer"
>
> -gdb_test_no_output "set circular-trace-buffer off" \
> - "set circular-trace-buffer off"
> + gdb_test_no_output "set circular-trace-buffer on" \
> + "make the target trace buffer circular"
>
> -gdb_test "show circular-trace-buffer" "Target's use of circular trace buffer is off." "show circular-trace-buffer (off)"
> + run_trace_experiment
>
> -# Body of test encased in a proc so we can return prematurely.
> -if { ![gdb_trace_circular_tests] } then {
> - # Set trace buffer attributes back to normal
> - trace_buffer_normal;
> -}
> + gdb_test "tstatus" \
> + ".*Buffer contains $decimal trace frames \\(of $decimal created total\\).*Trace buffer is circular.*" \
> + "trace buffer is circular"
>
> -# Finished!
> -gdb_test "tfind none" ".*" ""
> + # Frame 0 should not be at func0

First frame.

> + gdb_test "tfind start" ".*#0 func\[1-9\] .*" \
> + "first frame is NOT at func0";
> +
> + gdb_test "tfind none" ".*"
> +
> + gdb_test \
> + "tfind tracepoint 9" ".*Found trace frame $decimal, tracepoint 9.*" \
> + "find frame for tracepoint nine"
> +}

--
Pedro Alves