On Ubuntu 18.04 with GCC 7.5 Intel trace code fails to build due to
failure to convert from
lldb_private::process_linux::IntelPTPerThreadProcessTraceUP to
Expected<lldb_private::process_linux::IntelPTPerThreadProcessTraceUP>.
This commit explicitely marks those unique_ptr values as being moved
which fixes the conversion error.
Reviewed By: wallace
Differential Revision: https://reviews.llvm.org/D126402
When tracing on per-core mode, we are tracing all processes, which means
that after hitting a breakpoint, our process will stop running (thus
producing no more tracing data) but other processes will continue
writing to our trace buffers. This causes a big data loss for our trace.
As a way to remediate this, I'm adding some logic to pause and unpause
tracing based on the target's state. The earlier we do it the better,
however, I'm not adding the trigger at the earliest possible point for
simplicity of this diff. Later we can improve that part.
Differential Revision: https://reviews.llvm.org/D124962
This diffs implements per-core tracing on lldb-server. It also includes tests that ensure that tracing can be initiated from the client and that the jLLDBGetState ppacket returns the list of trace buffers per core.
This doesn't include any decoder changes.
Finally, this makes some little changes here and there improving the existing code.
A specific piece of code that can't reliably be tested is when tracing
per core fails due to permissions. In this case we add a
troubleshooting message and this is the manual test:
```
/proc/sys/kernel/perf_event_paranoid set to 1
(lldb) process trace start --per-core-tracing error: perf event syscall failed: Permission denied
You might need that /proc/sys/kernel/perf_event_paranoid has a value of 0 or -1.
``
Differential Revision: https://reviews.llvm.org/D124858
I'm refactoring IntelPTThreadTrace into IntelPTSingleBufferTrace so that it can
both single threads or single cores. In this diff I'm basically renaming the
class, moving it to its own file, and removing all the pieces that are not used
along with some basic cleanup.
Differential Revision: https://reviews.llvm.org/D124648
