[trace][intelpt] Support system-wide tracing [9] - Collect and return context switch traces

- Add collection of context switches per cpu grouped with the per-cpu intel pt traces.
- Move the state handling from the interl pt trace class to the PerfEvent one.
- Add support for stopping and enabling perf event groups.
- Return context switch entries as part of the jLLDBTraceGetState response.
- Move the triggers of whenever the process stopped or resumed. Now the will-resume notification is in a better location, which will ensure that we'll capture the instructions that will be executed.
- Remove IntelPTSingleBufferTraceUP. The unique pointer was useless.
- Add unit tests

Differential Revision: https://reviews.llvm.org/D125897

1 files changed, 10 insertions, 1 deletions

diff --git a/lldb/source/Host/common/NativeProcessProtocol.cpp b/lldb/source/Host/common/NativeProcessProtocol.cpp
index 31fc005..be521a3 100644
--- a/lldb/source/Host/common/NativeProcessProtocol.cpp
+++ b/lldb/source/Host/common/NativeProcessProtocol.cpp
@@ -312,7 +312,16 @@ void NativeProcessProtocol::SynchronouslyNotifyProcessStateChanged(
   Log *log = GetLog(LLDBLog::Process);
 
   m_delegate.ProcessStateChanged(this, state);
-  NotifyTracersProcessStateChanged(state);
+
+  switch (state) {
+  case eStateStopped:
+  case eStateExited:
+  case eStateCrashed:
+    NotifyTracersProcessDidStop();
+    break;
+  default:
+    break;
+  }
 
   LLDB_LOG(log, "sent state notification [{0}] from process {1}", state,
            GetID());