[LLDB][Telemetry]Define DebuggerTelemetryInfo and related methods (llvm#127696)

This type of entry is used to collect data about the debugger
startup/exit

Also introduced a helper ScopedDispatcher
---------

Co-authored-by: Jonas Devlieghere <[email protected]>
Co-authored-by: Pavel Labath <[email protected]>

Author: 3 people

lldb/include/lldb/Core/Telemetry.h

@@ -11,8 +11,10 @@
 
 #include "lldb/Core/StructuredDataImpl.h"
 #include "lldb/Interpreter/CommandReturnObject.h"
+#include "lldb/Utility/LLDBLog.h"
 #include "lldb/Utility/StructuredData.h"
 #include "lldb/lldb-forward.h"
+#include "llvm/ADT/FunctionExtras.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/JSON.h"
@@ -22,13 +24,20 @@
 #include <memory>
 #include <optional>
 #include <string>
-#include <unordered_map>
 
 namespace lldb_private {
 namespace telemetry {
 
+// We expect each (direct) subclass of LLDBTelemetryInfo to
+// have an LLDBEntryKind in the form 0b11xxxxxxxx
+// Specifically:
+//  - Length: 8 bits
+//  - First two bits (MSB) must be 11 - the common prefix
+// If any of the subclass has descendents, those descendents
+// must have their LLDBEntryKind in the similar form (ie., share common prefix)
 struct LLDBEntryKind : public ::llvm::telemetry::EntryKind {
-  static const llvm::telemetry::KindType BaseInfo = 0b11000;
+  static const llvm::telemetry::KindType BaseInfo = 0b11000000;
+  static const llvm::telemetry::KindType DebuggerInfo = 0b11000100;
 };
 
 /// Defines a convenient type for timestamp of various events.
@@ -41,6 +50,7 @@ struct LLDBBaseTelemetryInfo : public llvm::telemetry::TelemetryInfo {
   std::optional<SteadyTimePoint> end_time;
   // TBD: could add some memory stats here too?
 
+  lldb::user_id_t debugger_id = LLDB_INVALID_UID;
   Debugger *debugger;
 
   // For dyn_cast, isa, etc operations.
@@ -56,26 +66,93 @@ struct LLDBBaseTelemetryInfo : public llvm::telemetry::TelemetryInfo {
   void serialize(llvm::telemetry::Serializer &serializer) const override;
 };
 
+struct DebuggerInfo : public LLDBBaseTelemetryInfo {
+  std::string lldb_version;
+
+  bool is_exit_entry = false;
+
+  DebuggerInfo() = default;
+
+  llvm::telemetry::KindType getKind() const override {
+    return LLDBEntryKind::DebuggerInfo;
+  }
+
+  static bool classof(const llvm::telemetry::TelemetryInfo *T) {
+    // Subclasses of this is also acceptable
+    return (T->getKind() & LLDBEntryKind::DebuggerInfo) ==
+           LLDBEntryKind::DebuggerInfo;
+  }
+
+  void serialize(llvm::telemetry::Serializer &serializer) const override;
+};
+
 /// The base Telemetry manager instance in LLDB.
 /// This class declares additional instrumentation points
 /// applicable to LLDB.
 class TelemetryManager : public llvm::telemetry::Manager {
 public:
   llvm::Error preDispatch(llvm::telemetry::TelemetryInfo *entry) override;
 
+  const llvm::telemetry::Config *GetConfig();
+
   virtual llvm::StringRef GetInstanceName() const = 0;
+
   static TelemetryManager *GetInstance();
 
+  static TelemetryManager *GetInstanceIfEnabled();
+
 protected:
   TelemetryManager(std::unique_ptr<llvm::telemetry::Config> config);
 
   static void SetInstance(std::unique_ptr<TelemetryManager> manger);
 
 private:
   std::unique_ptr<llvm::telemetry::Config> m_config;
+  // Each instance of a TelemetryManager is assigned a unique ID.
+  const std::string m_id;
+
   static std::unique_ptr<TelemetryManager> g_instance;
 };
 
+/// Helper RAII class for collecting telemetry.
+template <typename Info> struct ScopedDispatcher {
+  // The debugger pointer is optional because we may not have a debugger yet.
+  // In that case, caller must set the debugger later.
+  ScopedDispatcher(llvm::unique_function<void(Info *info)> callback,
+                   Debugger *debugger = nullptr)
+      : m_callback(std::move(callback)) {
+    // Start the timer.
+    m_start_time = std::chrono::steady_clock::now();
+    m_info.debugger = debugger;
+  }
+
+  void SetDebugger(Debugger *debugger) { m_info.debugger = debugger; }
+
+  ~ScopedDispatcher() {
+    // If Telemetry is disabled (either at buildtime or runtime),
+    // then don't do anything.
+    TelemetryManager *manager = TelemetryManager::GetInstanceIfEnabled();
+    if (!manager)
+      return;
+
+    m_info.start_time = m_start_time;
+    // Populate common fields that we can only set now.
+    m_info.end_time = std::chrono::steady_clock::now();
+    // The callback will set the remaining fields.
+    m_callback(&m_info);
+    // And then we dispatch.
+    if (llvm::Error er = manager->dispatch(&m_info)) {
+      LLDB_LOG_ERROR(GetLog(LLDBLog::Object), std::move(er),
+                     "Failed to dispatch entry of type: {0}", m_info.getKind());
+    }
+  }
+
+private:
+  SteadyTimePoint m_start_time;
+  llvm::unique_function<void(Info *info)> m_callback;
+  Info m_info;
+};
+
 } // namespace telemetry
 } // namespace lldb_private
 #endif // LLDB_CORE_TELEMETRY_H

lldb/source/Core/Debugger.cpp

@@ -17,6 +17,7 @@
 #include "lldb/Core/PluginManager.h"
 #include "lldb/Core/Progress.h"
 #include "lldb/Core/StreamAsynchronousIO.h"
+#include "lldb/Core/Telemetry.h"
 #include "lldb/DataFormatters/DataVisualization.h"
 #include "lldb/Expression/REPL.h"
 #include "lldb/Host/File.h"
@@ -52,6 +53,7 @@
 #include "lldb/Utility/State.h"
 #include "lldb/Utility/Stream.h"
 #include "lldb/Utility/StreamString.h"
+#include "lldb/Version/Version.h"
 #include "lldb/lldb-enumerations.h"
 
 #if defined(_WIN32)
@@ -62,13 +64,15 @@
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/iterator.h"
+#include "llvm/Config/llvm-config.h"
 #include "llvm/Support/DynamicLibrary.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Process.h"
 #include "llvm/Support/ThreadPool.h"
 #include "llvm/Support/Threading.h"
 #include "llvm/Support/raw_ostream.h"
 
+#include <chrono>
 #include <cstdio>
 #include <cstdlib>
 #include <cstring>
@@ -761,7 +765,14 @@ void Debugger::InstanceInitialize() {
 
 DebuggerSP Debugger::CreateInstance(lldb::LogOutputCallback log_callback,
                                     void *baton) {
+  lldb_private::telemetry::ScopedDispatcher<
+      lldb_private::telemetry::DebuggerInfo>
+      helper([](lldb_private::telemetry::DebuggerInfo *entry) {
+        entry->lldb_version = lldb_private::GetVersion();
+      });
   DebuggerSP debugger_sp(new Debugger(log_callback, baton));
+  helper.SetDebugger(debugger_sp.get());
+
   if (g_debugger_list_ptr && g_debugger_list_mutex_ptr) {
     std::lock_guard<std::recursive_mutex> guard(*g_debugger_list_mutex_ptr);
     g_debugger_list_ptr->push_back(debugger_sp);
@@ -987,6 +998,12 @@ void Debugger::Clear() {
   //     static void Debugger::Destroy(lldb::DebuggerSP &debugger_sp);
   //     static void Debugger::Terminate();
   llvm::call_once(m_clear_once, [this]() {
+    telemetry::ScopedDispatcher<telemetry::DebuggerInfo> helper(
+        [this](lldb_private::telemetry::DebuggerInfo *info) {
+          assert(this == info->debugger);
+          info->is_exit_entry = true;
+        },
+        this);
     ClearIOHandlers();
     StopIOHandlerThread();
     StopEventHandlerThread();

lldb/source/Core/Telemetry.cpp

@@ -7,8 +7,10 @@
 //===----------------------------------------------------------------------===//
 #include "lldb/Core/Telemetry.h"
 #include "lldb/Core/Debugger.h"
+#include "lldb/Core/Telemetry.h"
 #include "lldb/Utility/LLDBLog.h"
 #include "lldb/Utility/UUID.h"
+#include "lldb/Version/Version.h"
 #include "lldb/lldb-enumerations.h"
 #include "lldb/lldb-forward.h"
 #include "llvm/ADT/StringRef.h"
@@ -30,6 +32,26 @@ static uint64_t ToNanosec(const SteadyTimePoint Point) {
   return std::chrono::nanoseconds(Point.time_since_epoch()).count();
 }
 
+// Generate a unique string. This should be unique across different runs.
+// We build such string by combining three parts:
+// <16 random bytes>_<timestamp>
+// This reduces the chances of getting the same UUID, even when the same
+// user runs the two copies of binary at the same time.
+static std::string MakeUUID() {
+  uint8_t random_bytes[16];
+  std::string randomString = "_";
+  if (auto ec = llvm::getRandomBytes(random_bytes, 16)) {
+    LLDB_LOG(GetLog(LLDBLog::Object),
+             "Failed to generate random bytes for UUID: {0}", ec.message());
+  } else {
+    randomString = UUID(random_bytes).GetAsString();
+  }
+
+  return llvm::formatv(
+      "{0}_{1}", randomString,
+      std::chrono::steady_clock::now().time_since_epoch().count());
+}
+
 void LLDBBaseTelemetryInfo::serialize(Serializer &serializer) const {
   serializer.write("entry_kind", getKind());
   serializer.write("session_id", SessionId);
@@ -38,38 +60,47 @@ void LLDBBaseTelemetryInfo::serialize(Serializer &serializer) const {
     serializer.write("end_time", ToNanosec(end_time.value()));
 }
 
-[[maybe_unused]] static std::string MakeUUID(Debugger *debugger) {
-  uint8_t random_bytes[16];
-  if (auto ec = llvm::getRandomBytes(random_bytes, 16)) {
-    LLDB_LOG(GetLog(LLDBLog::Object),
-             "Failed to generate random bytes for UUID: {0}", ec.message());
-    // Fallback to using timestamp + debugger ID.
-    return llvm::formatv(
-        "{0}_{1}", std::chrono::steady_clock::now().time_since_epoch().count(),
-        debugger->GetID());
-  }
-  return UUID(random_bytes).GetAsString();
+void DebuggerInfo::serialize(Serializer &serializer) const {
+  LLDBBaseTelemetryInfo::serialize(serializer);
+
+  serializer.write("lldb_version", lldb_version);
+  serializer.write("is_exit_entry", is_exit_entry);
 }
 
 TelemetryManager::TelemetryManager(std::unique_ptr<Config> config)
-    : m_config(std::move(config)) {}
+    : m_config(std::move(config)), m_id(MakeUUID()) {}
 
 llvm::Error TelemetryManager::preDispatch(TelemetryInfo *entry) {
-  // Do nothing for now.
-  // In up-coming patch, this would be where the manager
-  // attach the session_uuid to the entry.
+  // Assign the manager_id, and debugger_id, if available, to this entry.
+  LLDBBaseTelemetryInfo *lldb_entry = llvm::cast<LLDBBaseTelemetryInfo>(entry);
+  lldb_entry->SessionId = m_id;
+  if (Debugger *debugger = lldb_entry->debugger)
+    lldb_entry->debugger_id = debugger->GetID();
   return llvm::Error::success();
 }
 
+const Config *TelemetryManager::GetConfig() { return m_config.get(); }
+
 std::unique_ptr<TelemetryManager> TelemetryManager::g_instance = nullptr;
 TelemetryManager *TelemetryManager::GetInstance() {
   if (!Config::BuildTimeEnableTelemetry)
     return nullptr;
   return g_instance.get();
 }
 
+TelemetryManager *TelemetryManager::GetInstanceIfEnabled() {
+  // Telemetry may be enabled at build time but disabled at runtime.
+  if (TelemetryManager *ins = TelemetryManager::GetInstance()) {
+    if (ins->GetConfig()->EnableTelemetry)
+      return ins;
+  }
+
+  return nullptr;
+}
+
 void TelemetryManager::SetInstance(std::unique_ptr<TelemetryManager> manager) {
-  g_instance = std::move(manager);
+  if (Config::BuildTimeEnableTelemetry)
+    g_instance = std::move(manager);
 }
 
 } // namespace telemetry