i#6367: Insert FILTER_ENDPOINT when going to TRACE from COUNT also.

[prasun3]

For BIMODAL traces (see #5199), the normal transition is from COUNT to L0_FILTER to TRACE. But some threads may transition from COUNT to TRACE directly e.g., if they were not scheduled during L0_FILTER mode. In this case, the FILTER_ENDPOINT marker is not inserted currently, which leads to raw2trace failures.

An example cmd line that reproduces the bug is shown below. Note that there is only one worker thread which transitions through L0_FILTER and TRACE mode while the main thread is still in COUNT mode.

bin64/drrun -t drcachesim -offline \
-trace_after_instrs 2200K -L0_filter_until_instrs 10K -max_trace_size 10K -- ./threadsig 1 1000

Issue: #6367

[prasun3]

The aarch64 failures seem related to this feature but I have no idea why this would fail only for aarch64.

The 'x86-64-ubuntu22' failure is api.rseq.

[derekbruening]

The 'x86-64-ubuntu22' failure is api.rseq.

In general, please look at the failure reason and cite the issue number. Looks like failure to synchronize #6185 which nobody seems able to reproduce locally to try to fix.

[prasun3]

x86-64 failed with #6185 again

[prasun3]

x86-64-ubuntu22 failed with #6185 again

[prasun3]

x86-32 failed with #6303

2023-10-19T03:16:51.7804322Z         Start 303: code_api|tool.drcachesim.opcode_mix
2023-10-19T03:16:51.7808645Z 303: Test command: /home/runner/work/dynamorio/dynamorio/build_debug-internal-32/bin32/drrun "-s" "90" "-quiet" "-debug" "-killpg" "-stderr_mask" "0xC" "-dumpcore_mask" "0" "-code_api" "-t" "drcachesim" "-ipc_name" "/home/runner/work/dynamorio/dynamorio/build_debug-internal-32/suite/tests/drtestpipe_opcode_mix" "-instr_encodings" "-simulator_type" "opcode_mix" "--" "/home/runner/work/dynamorio/dynamorio/build_debug-internal-32/suite/tests/bin/simple_app"
2023-10-19T03:16:51.7812271Z 303: Test timeout computed to be: 600
2023-10-19T03:16:51.7947961Z 303: Hello, world!
2023-10-19T03:16:51.7948379Z 303: Encoding size 2 != instr size 6
2023-10-19T03:16:51.7950291Z 303: drcachesim: /home/runner/work/dynamorio/dynamorio/clients/drcachesim/reader/reader.cpp:203: virtual bool dynamorio::drmemtrace::reader_t::process_input_entry(): Assertion `false' failed.
2023-10-19T03:16:51.7952833Z 303/414 Test #303: code_api|tool.drcachesim.opcode_mix ..............................***Failed  Required regular expression not found. Regex=[^Hello, world!