[lldb] [gdb-remote server] Refactor handling qSupported

Refactor handling qSupported to use a virtual HandleFeatures() method.
The client-provided features are split into an array and passed
to the method.  The method returns an array of server features that are
concatenated into the qSupported response to the server.

The base implementation of HandleFeatures()
in GDBRemoteCommunicationServerCommon now includes only flags common
to both platform server and llgs, while llgs-specific flags are inserted
in GDBRemoteCommunicationServerLLGS.

Differential Revision: https://reviews.llvm.org/D100140

1 files changed, 19 insertions, 20 deletions

diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.cpp
index c933364..a0d88b3 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.cpp
@@ -831,26 +831,10 @@ GDBRemoteCommunicationServerCommon::Handle_qPlatform_chmod(
 GDBRemoteCommunication::PacketResult
 GDBRemoteCommunicationServerCommon::Handle_qSupported(
     StringExtractorGDBRemote &packet) {
-  StreamGDBRemote response;
-
-  // Features common to lldb-platform and llgs.
-  uint32_t max_packet_size = 128 * 1024; // 128KBytes is a reasonable max packet
-                                         // size--debugger can always use less
-  response.Printf("PacketSize=%x", max_packet_size);
-
-  response.PutCString(";QStartNoAckMode+");
-  response.PutCString(";QThreadSuffixSupported+");
-  response.PutCString(";QListThreadsInStopReply+");
-  response.PutCString(";qEcho+");
-  response.PutCString(";qXfer:features:read+");
-#if defined(__linux__) || defined(__NetBSD__) || defined(__FreeBSD__)
-  response.PutCString(";QPassSignals+");
-  response.PutCString(";qXfer:auxv:read+");
-  response.PutCString(";qXfer:libraries-svr4:read+");
-#endif
-  response.PutCString(";multiprocess+");
-
-  return SendPacketNoLock(response.GetString());
+  // Parse client-indicated features.
+  llvm::SmallVector<llvm::StringRef, 4> client_features;
+  packet.GetStringRef().split(client_features, ';');
+  return SendPacketNoLock(llvm::join(HandleFeatures(client_features), ";"));
 }
 
 GDBRemoteCommunication::PacketResult
@@ -1312,3 +1296,18 @@ GDBRemoteCommunicationServerCommon::GetModuleInfo(llvm::StringRef module_path,
 
   return matched_module_spec;
 }
+
+std::vector<std::string> GDBRemoteCommunicationServerCommon::HandleFeatures(
+    const llvm::ArrayRef<llvm::StringRef> client_features) {
+  // 128KBytes is a reasonable max packet size--debugger can always use less.
+  constexpr uint32_t max_packet_size = 128 * 1024;
+
+  // Features common to platform server and llgs.
+  return {
+      llvm::formatv("PacketSize={0}", max_packet_size),
+      "QStartNoAckMode+",
+      "QThreadSuffixSupported+",
+      "QListThreadsInStopReply+",
+      "qEcho+",
+  };
+}