[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, 8 insertions, 3 deletions

diff --git a/lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp b/lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp
index a7869d2..429c68a 100644
--- a/lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp
+++ b/lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp
@@ -898,6 +898,8 @@ Status NativeProcessLinux::Resume(const ResumeActionList &resume_actions) {
   Log *log = GetLog(POSIXLog::Process);
   LLDB_LOG(log, "pid {0}", GetID());
 
+  NotifyTracersProcessWillResume();
+
   bool software_single_step = !SupportHardwareSingleStepping();
 
   if (software_single_step) {
@@ -1665,9 +1667,12 @@ void NativeProcessLinux::StopTrackingThread(NativeThreadLinux &thread) {
   SignalIfAllThreadsStopped();
 }
 
-void NativeProcessLinux::NotifyTracersProcessStateChanged(
-    lldb::StateType state) {
-  m_intel_pt_collector.OnProcessStateChanged(state);
+void NativeProcessLinux::NotifyTracersProcessDidStop() {
+  m_intel_pt_collector.ProcessDidStop();
+}
+
+void NativeProcessLinux::NotifyTracersProcessWillResume() {
+  m_intel_pt_collector.ProcessWillResume();
 }
 
 Status NativeProcessLinux::NotifyTracersOfNewThread(lldb::tid_t tid) {