[trace][intel-pt] Implement trace start and trace stop

This implements the interactive trace start and stop methods.

This diff ended up being much larger than I anticipated because, by doing it, I found that I had implemented in the beginning many things in a non optimal way. In any case, the code is much better now.

There's a lot of boilerplate code due to the gdb-remote protocol, but the main changes are:

- New tracing packets: jLLDBTraceStop, jLLDBTraceStart, jLLDBTraceGetBinaryData. The gdb-remote packet definitions are quite comprehensive.
- Implementation of the "process trace start|stop" and "thread trace start|stop" commands.
- Implementaiton of an API in Trace.h to interact with live traces.
- Created an IntelPTDecoder for live threads, that use the debugger's stop id as checkpoint for its internal cache.
- Added a functionality to stop the process in case "process tracing" is enabled and a new thread can't traced.
- Added tests

I have some ideas to unify the code paths for post mortem and live threads, but I'll do that in another diff.

Differential Revision: https://reviews.llvm.org/D91679

5 files changed, 185 insertions, 38 deletions

diff --git a/lldb/source/Utility/CMakeLists.txt b/lldb/source/Utility/CMakeLists.txt
index 3aca72d..6790e47 100644
--- a/lldb/source/Utility/CMakeLists.txt
+++ b/lldb/source/Utility/CMakeLists.txt
@@ -65,7 +65,8 @@ add_lldb_library(lldbUtility
   StructuredData.cpp
   TildeExpressionResolver.cpp
   Timer.cpp
-  TraceOptions.cpp
+  TraceGDBRemotePackets.cpp
+  TraceIntelPTGDBRemotePackets.cpp
   UnimplementedError.cpp
   UUID.cpp
   UriParser.cpp
diff --git a/lldb/source/Utility/StringExtractorGDBRemote.cpp b/lldb/source/Utility/StringExtractorGDBRemote.cpp
index 2110265..6815ddf 100644
--- a/lldb/source/Utility/StringExtractorGDBRemote.cpp
+++ b/lldb/source/Utility/StringExtractorGDBRemote.cpp
@@ -303,18 +303,17 @@ StringExtractorGDBRemote::GetServerPacketType() const {
       return eServerPacketType_jSignalsInfo;
     if (PACKET_MATCHES("jThreadsInfo"))
       return eServerPacketType_jThreadsInfo;
-    if (PACKET_STARTS_WITH("jTraceBufferRead:"))
-      return eServerPacketType_jTraceBufferRead;
-    if (PACKET_STARTS_WITH("jTraceConfigRead:"))
-      return eServerPacketType_jTraceConfigRead;
-    if (PACKET_STARTS_WITH("jTraceMetaRead:"))
-      return eServerPacketType_jTraceMetaRead;
-    if (PACKET_STARTS_WITH("jTraceStart:"))
-      return eServerPacketType_jTraceStart;
-    if (PACKET_STARTS_WITH("jTraceStop:"))
-      return eServerPacketType_jTraceStop;
-    if (PACKET_MATCHES("jLLDBTraceSupportedType"))
-      return eServerPacketType_jLLDBTraceSupportedType;
+
+    if (PACKET_MATCHES("jLLDBTraceSupported"))
+      return eServerPacketType_jLLDBTraceSupported;
+    if (PACKET_STARTS_WITH("jLLDBTraceStop:"))
+      return eServerPacketType_jLLDBTraceStop;
+    if (PACKET_STARTS_WITH("jLLDBTraceStart:"))
+      return eServerPacketType_jLLDBTraceStart;
+    if (PACKET_STARTS_WITH("jLLDBTraceGetState:"))
+      return eServerPacketType_jLLDBTraceGetState;
+    if (PACKET_STARTS_WITH("jLLDBTraceGetBinaryData:"))
+      return eServerPacketType_jLLDBTraceGetBinaryData;
     break;
 
   case 'v':
diff --git a/lldb/source/Utility/TraceGDBRemotePackets.cpp b/lldb/source/Utility/TraceGDBRemotePackets.cpp
new file mode 100644
index 0000000..5c1326a
--- /dev/null
+++ b/lldb/source/Utility/TraceGDBRemotePackets.cpp
@@ -0,0 +1,130 @@
+//===-- TraceGDBRemotePackets.cpp -------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "lldb/Utility/TraceGDBRemotePackets.h"
+
+using namespace llvm;
+using namespace llvm::json;
+
+namespace lldb_private {
+/// jLLDBTraceSupported
+/// \{
+bool fromJSON(const json::Value &value, TraceSupportedResponse &packet,
+              Path path) {
+  ObjectMapper o(value, path);
+  return o && o.map("description", packet.description) &&
+         o.map("name", packet.name);
+}
+
+json::Value toJSON(const TraceSupportedResponse &packet) {
+  return json::Value(
+      Object{{"description", packet.description}, {"name", packet.name}});
+}
+/// \}
+
+/// jLLDBTraceStart
+/// \{
+bool TraceStartRequest::IsProcessTracing() const { return !(bool)tids; }
+
+bool fromJSON(const json::Value &value, TraceStartRequest &packet, Path path) {
+  ObjectMapper o(value, path);
+  return o && o.map("type", packet.type) && o.map("tids", packet.tids);
+}
+
+json::Value toJSON(const TraceStartRequest &packet) {
+  return json::Value(Object{{"tids", packet.tids}, {"type", packet.type}});
+}
+/// \}
+
+/// jLLDBTraceStop
+/// \{
+TraceStopRequest::TraceStopRequest(llvm::StringRef type,
+                                   const std::vector<lldb::tid_t> &tids_)
+    : type(type) {
+  tids.emplace();
+  for (lldb::tid_t tid : tids_)
+    tids->push_back(static_cast<int64_t>(tid));
+}
+
+bool TraceStopRequest::IsProcessTracing() const { return !(bool)tids; }
+
+bool fromJSON(const json::Value &value, TraceStopRequest &packet, Path path) {
+  ObjectMapper o(value, path);
+  return o && o.map("type", packet.type) && o.map("tids", packet.tids);
+}
+
+json::Value toJSON(const TraceStopRequest &packet) {
+  return json::Value(Object{{"type", packet.type}, {"tids", packet.tids}});
+}
+/// \}
+
+/// jLLDBTraceGetState
+/// \{
+bool fromJSON(const json::Value &value, TraceGetStateRequest &packet,
+              Path path) {
+  ObjectMapper o(value, path);
+  return o && o.map("type", packet.type);
+}
+
+json::Value toJSON(const TraceGetStateRequest &packet) {
+  return json::Value(Object{{"type", packet.type}});
+}
+
+bool fromJSON(const json::Value &value, TraceBinaryData &packet, Path path) {
+  ObjectMapper o(value, path);
+  return o && o.map("kind", packet.kind) && o.map("size", packet.size);
+}
+
+json::Value toJSON(const TraceBinaryData &packet) {
+  return json::Value(Object{{"kind", packet.kind}, {"size", packet.size}});
+}
+
+bool fromJSON(const json::Value &value, TraceThreadState &packet, Path path) {
+  ObjectMapper o(value, path);
+  return o && o.map("tid", packet.tid) &&
+         o.map("binaryData", packet.binaryData);
+}
+
+json::Value toJSON(const TraceThreadState &packet) {
+  return json::Value(
+      Object{{"tid", packet.tid}, {"binaryData", packet.binaryData}});
+}
+
+bool fromJSON(const json::Value &value, TraceGetStateResponse &packet,
+              Path path) {
+  ObjectMapper o(value, path);
+  return o && o.map("tracedThreads", packet.tracedThreads) &&
+         o.map("processBinaryData", packet.processBinaryData);
+}
+
+json::Value toJSON(const TraceGetStateResponse &packet) {
+  return json::Value(Object{{"tracedThreads", packet.tracedThreads},
+                            {"processBinaryData", packet.processBinaryData}});
+}
+/// \}
+
+/// jLLDBTraceGetBinaryData
+/// \{
+json::Value toJSON(const TraceGetBinaryDataRequest &packet) {
+  return json::Value(Object{{"type", packet.type},
+                            {"kind", packet.kind},
+                            {"offset", packet.offset},
+                            {"tid", packet.tid},
+                            {"size", packet.size}});
+}
+
+bool fromJSON(const json::Value &value, TraceGetBinaryDataRequest &packet,
+              Path path) {
+  ObjectMapper o(value, path);
+  return o && o.map("type", packet.type) && o.map("kind", packet.kind) &&
+         o.map("tid", packet.tid) && o.map("offset", packet.offset) &&
+         o.map("size", packet.size);
+}
+/// \}
+
+} // namespace lldb_private
diff --git a/lldb/source/Utility/TraceIntelPTGDBRemotePackets.cpp b/lldb/source/Utility/TraceIntelPTGDBRemotePackets.cpp
new file mode 100644
index 0000000..69f773f
--- /dev/null
+++ b/lldb/source/Utility/TraceIntelPTGDBRemotePackets.cpp
@@ -0,0 +1,42 @@
+//===-- TraceIntelPTGDBRemotePackets.cpp ------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "lldb/Utility/TraceIntelPTGDBRemotePackets.h"
+
+using namespace llvm;
+using namespace llvm::json;
+
+namespace lldb_private {
+
+bool fromJSON(const json::Value &value, TraceIntelPTStartRequest &packet,
+              Path path) {
+  ObjectMapper o(value, path);
+  if (!o || !fromJSON(value, (TraceStartRequest &)packet, path) ||
+      !o.map("threadBufferSize", packet.threadBufferSize) ||
+      !o.map("processBufferSizeLimit", packet.processBufferSizeLimit))
+    return false;
+  if (packet.tids && packet.processBufferSizeLimit) {
+    path.report("processBufferSizeLimit must be provided");
+    return false;
+  }
+  if (!packet.tids && !packet.processBufferSizeLimit) {
+    path.report("processBufferSizeLimit must not be provided");
+    return false;
+  }
+  return true;
+}
+
+json::Value toJSON(const TraceIntelPTStartRequest &packet) {
+  json::Value base = toJSON((const TraceStartRequest &)packet);
+  base.getAsObject()->try_emplace("threadBufferSize", packet.threadBufferSize);
+  base.getAsObject()->try_emplace("processBufferSizeLimit",
+                                  packet.processBufferSizeLimit);
+  return base;
+}
+
+} // namespace lldb_private
diff --git a/lldb/source/Utility/TraceOptions.cpp b/lldb/source/Utility/TraceOptions.cpp
deleted file mode 100644
index 292fb60..0000000
--- a/lldb/source/Utility/TraceOptions.cpp
+++ /dev/null
@@ -1,25 +0,0 @@
-//===-- TraceOptions.cpp ----------------------------------------*- C++ -*-===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-#include "lldb/Utility/TraceOptions.h"
-
-using namespace lldb_private;
-
-namespace llvm {
-namespace json {
-
-bool fromJSON(const Value &value, TraceTypeInfo &info, Path path) {
-  ObjectMapper o(value, path);
-  if (!o)
-    return false;
-  o.map("description", info.description);
-  return o.map("name", info.name);
-}
-
-} // namespace json
-} // namespace llvm