Re: [patch] circ.exp

Abid, Hafiz
2013-05-08T10:12:01Z

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Hi Pedro,
Thanks for your review. Here is an updated patch.

> s/size buffer size/buffer size/
Fixed.

> > +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
> }
> }
I have used similar code sequence as you described above. But I was
wondering if we can
issue an unsupported call in the 2nd '-re' and then return. That should
eliminate the need
for 'circular_supported'. It also generates an extra pass while we then
call unsupported below.
>
> 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.

Fixed. I tested by disabling the support of the packet in gdbserver as
you suggested.
I noticed that when support was disabled, then 'set
circular-trace-buffer on'
gives 'Target does not support this command' error.
I modified the test a bit to handle that error. Similar case with
'set trace-buffer-size' when support for QTBuffer:size is disabled.

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

>
> Likewise.
>
Done.

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

>
> s/frame 0/the first frame/
>
Fixed.

> 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".
I am using "tfind pc func9" now. It also forced me to put the
tracepoints
using 'trace *func9' in 'set_a_tracepoint' so that tracepoint address
matches
here.

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

>
> likewise for frame nine.
>
Fixed.

> > +# 1) frame zero will be overwritten and therefore unavailable
>
> "frame zero" here.
>
Fixed.

> > -# Finished!
> > -gdb_test "tfind none" ".*" ""
> > + # Frame 0 should not be at func0
>
> First frame.
>
Fixed.

> > + 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"
> > +}

Thanks,
Abid

gdb/testsuite/ChangeLog:
2013-05-08 Hafiz Abid Qadeer <abidh@codesourcery.com>

* gdb.trace/circ.exp: Remove unnecessary 'if then' checks.
(set_a_tracepoint): Set tracepoint before prologue.
(run_trace_experiment): Test setup_tracepoints and 'break end'
in it.
(trace_buffer_normal): Remove.
(gdb_trace_circular_tests): Remove. Move tests to...
(top level): ...here. Call 'runto_main' before checking for
trace support. Use commands to check the support for circular
trace buffer and changing of trace buffer size. Add test
to calculate size of single frame. Use this size to
calculate the size of trace buffer. Use 'tfind pc func9'
instead of 'tfind 9'. Use 'with_test_prefix'.

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diff --git a/gdb/testsuite/gdb.trace/circ.exp b/gdb/testsuite/gdb.trace/circ.exp
index 4c47228..3310800 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 +22,264 @@ 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 buffer size as in
+# 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
+# Set a tracepoint on given func. The tracepoint is set at entry
+# address and not 'after prologue' address.
+proc set_a_tracepoint { func } {
+ gdb_test "trace \*$func" "Tracepoint \[0-9\]+ at .*" \
+ "set tracepoint at $func"
+ gdb_trace_setactions "set actions for $func" "" "collect testload" "^$"
+}

- 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
+# Sets the tracepoints from func0 to func9 using set_a_tracepoint.
+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
}

-# 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 {
+# Start the trace, run to end and then stop the trace.
+proc run_trace_experiment { } {
+ global decimal
+
+ setup_tracepoints
+ gdb_test "break end" "Breakpoint $decimal.*" "breakpoint at end"
+ gdb_test "tstart" "\[\r\n\]*" "start trace experiment"
+ gdb_test "continue" "Continuing.*Breakpoint \[0-9\]+, end.*" \
+ "run to end"
+ gdb_test "tstop" "\[\r\n\]*" "stop trace experiment"
+}
+
+if { ![runto_main] } {
+ fail "can't run to main to check for trace support"
+ return -1
+}
+
+if { ![gdb_target_supports_trace] } {
+ unsupported "target does not support trace"
+ return 1
+}
+
+set test "set circular-trace-buffer on"
+gdb_test_multiple "set circular-trace-buffer on" $test {
+ -re ".*Target does not support this command.*$gdb_prompt $" {
+ unsupported "target does not support circular trace buffer"
return 1
}
- if [gdb_trace_setactions "set actions for $func" \
- "" \
- "collect testload" "^$"] then {
+ -re "$gdb_prompt $" {
+ pass $test
+ }
+}
+
+set circular_supported -1
+set test "check whether circular buffer is supported"
+
+gdb_test_multiple "tstatus" $test {
+ -re ".*Trace buffer is circular.*$gdb_prompt $" {
+ set circular_supported 1
+ pass $test
+ }
+ -re "$gdb_prompt $" {
+ pass $test
+ }
+}
+
+if { $circular_supported < 0 } {
+ unsupported "target does not support circular trace buffer"
+ return 1
+}
+
+gdb_test "show circular-trace-buffer" \
+ "Target's use of circular trace buffer is on." \
+ "show circular-trace-buffer (on)"
+
+# Check if changing the trace buffer size is supported. This step is
+# repeated twice. This helps in case if trace buffer size is 100.
+set test_size 100
+set test "change buffer size to $test_size"
+gdb_test_multiple "set trace-buffer-size $test_size" $test {
+ -re ".*Target does not support this command.*$gdb_prompt $" {
+ unsupported "target does not support changing trace buffer size"
return 1
}
- return 0
+ -re "$gdb_prompt $" {
+ pass $test
+ }
}

-# 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
-}
-
-# return 0 for success, 1 for failure
-proc trace_buffer_normal { } {
- global gdb_prompt
-
- 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
- pass $test
- }
- -re "\r\n$gdb_prompt $" {
+set test "check whether setting trace buffer size is supported"
+gdb_test_multiple "tstatus" $test {
+ -re ".*Trace buffer has ($decimal) bytes of ($decimal) bytes free.*$gdb_prompt $" {
+ set total_size $expect_out(2,string)
+ if { $test_size != $total_size } {
+ unsupported "target does not support changing trace buffer size"
+ return 1
}
+ pass $test
}
- if { !$ok } {
- unsupported $test
- return 1
+}
+
+set test_size 400
+gdb_test_no_output "set trace-buffer-size $test_size" \
+ "change buffer size to $test_size"
+
+gdb_test_multiple "tstatus" $test {
+ -re ".*Trace buffer has ($decimal) bytes of ($decimal) bytes free.*$gdb_prompt $" {
+ set total_size $expect_out(2,string)
+ if { $test_size != $total_size } {
+ unsupported "target does not support changing trace buffer size"
+ return 1
+ }
+ pass $test
}
+}
+
+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:circular:0"
- gdb_test_multiple $test $test {
- -re "received: .OK.\r\n$gdb_prompt $" {
- set ok 1
+# Determine the size used by a single frame. Set a single tracepoint,
+# run and then check the total and free size 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
}

- return 0
+ if { $free_size < 0 } {
+ return 1
+ }
}

-# 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 }
+ run_trace_experiment

- gdb_test "break begin" ".*" ""
- gdb_test "break end" ".*" ""
- gdb_test "tstop" ".*" ""
- gdb_test "tfind none" ".*" ""
+ # Check that teh first frame is actually at func0.
+ gdb_test "tfind start" ".*#0 func0 .*" \
+ "first frame is at func0"

- if [setup_tracepoints] then { return 1 }
-
- # 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 pc func9" \
+ ".*Found trace frame $decimal, tracepoint $decimal.*" \
+ "find frame for 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 for func0 is still
+# collected, but frame for func9 is not.

- 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"

- if [gdb_test "tfind none" \
- "#0 end .*" \
- "quit trace debugging, pass 3"] then { return 1 }
+ run_trace_experiment

- return 0
+ gdb_test "tfind start" ".*#0 func0 .*" \
+ "first frame is at func0"
+
+ gdb_test "tfind pc func9" ".* failed to find .*" \
+ "find frame for func9";
}

-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) the first frame will be overwritten and therefore unavailable
+# 2) the earliest frame in the buffer will not be for func0.
+# 3) the frame for func9 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" ".*" ""
+ # The first frame should not be at func0
+ gdb_test "tfind start" ".*#0 func\[1-9\] .*" \
+ "first frame is NOT at func0"
+
+ gdb_test \
+ "tfind pc func9" \
+ ".*Found trace frame $decimal, tracepoint $decimal.*" \
+ "find frame for func9"
+}