[lldb] [llgs] Support resuming one process with PID!=current via vCont

Extend vCont function to support resuming a process with an arbitrary
PID, that could be different than the one selected via Hc (or no process
at all may be selected).  Resuming more than one process simultaneously
is not supported yet.

Remove the ReadTid() method that was only used by Handle_vCont(),
and furthermore it was wrongly using m_current_process rather than
m_continue_process.

Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.llvm.org/D127862

1 files changed, 47 insertions, 60 deletions

diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp
index 1ff0b7f..f6b61f5 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp
@@ -1674,12 +1674,7 @@ GDBRemoteCommunicationServerLLGS::Handle_vCont(
     return SendIllFormedResponse(packet, "Missing action from vCont package");
   }
 
-  // Check if this is all continue (no options or ";c").
-  if (::strcmp(packet.Peek(), ";c") == 0) {
-    // Move past the ';', then do a simple 'c'.
-    packet.SetFilePos(packet.GetFilePos() + 1);
-    return Handle_c(packet);
-  } else if (::strcmp(packet.Peek(), ";s") == 0) {
+  if (::strcmp(packet.Peek(), ";s") == 0) {
     // Move past the ';', then do a simple 's'.
     packet.SetFilePos(packet.GetFilePos() + 1);
     return Handle_s(packet);
@@ -1688,13 +1683,7 @@ GDBRemoteCommunicationServerLLGS::Handle_vCont(
     return SendOKResponse();
   }
 
-  // Ensure we have a native process.
-  if (!m_continue_process) {
-    LLDB_LOG(log, "no debugged process");
-    return SendErrorResponse(0x36);
-  }
-
-  ResumeActionList thread_actions;
+  std::unordered_map<lldb::pid_t, ResumeActionList> thread_actions;
 
   while (packet.GetBytesLeft() && *packet.Peek() == ';') {
     // Skip the semi-colon.
@@ -1737,32 +1726,62 @@ GDBRemoteCommunicationServerLLGS::Handle_vCont(
       break;
     }
 
+    lldb::pid_t pid = StringExtractorGDBRemote::AllProcesses;
+    lldb::tid_t tid = StringExtractorGDBRemote::AllThreads;
+
     // Parse out optional :{thread-id} value.
     if (packet.GetBytesLeft() && (*packet.Peek() == ':')) {
       // Consume the separator.
       packet.GetChar();
 
-      llvm::Expected<lldb::tid_t> tid_ret =
-          ReadTid(packet, /*allow_all=*/true, m_continue_process->GetID());
-      if (!tid_ret)
-        return SendErrorResponse(tid_ret.takeError());
+      auto pid_tid = packet.GetPidTid(StringExtractorGDBRemote::AllProcesses);
+      if (!pid_tid)
+        return SendIllFormedResponse(packet, "Malformed thread-id");
 
-      thread_action.tid = tid_ret.get();
-      if (thread_action.tid == StringExtractorGDBRemote::AllThreads)
-        thread_action.tid = LLDB_INVALID_THREAD_ID;
+      pid = pid_tid->first;
+      tid = pid_tid->second;
     }
 
-    thread_actions.Append(thread_action);
-  }
+    if (pid == StringExtractorGDBRemote::AllProcesses) {
+      if (m_debugged_processes.size() > 1)
+        return SendIllFormedResponse(
+            packet, "Resuming multiple processes not supported yet");
+      if (!m_continue_process) {
+        LLDB_LOG(log, "no debugged process");
+        return SendErrorResponse(0x36);
+      }
+      pid = m_continue_process->GetID();
+    }
 
-  Status error = m_continue_process->Resume(thread_actions);
-  if (error.Fail()) {
-    LLDB_LOG(log, "vCont failed for process {0}: {1}",
-             m_continue_process->GetID(), error);
-    return SendErrorResponse(GDBRemoteServerError::eErrorResume);
+    if (tid == StringExtractorGDBRemote::AllThreads)
+      tid = LLDB_INVALID_THREAD_ID;
+
+    thread_action.tid = tid;
+
+    thread_actions[pid].Append(thread_action);
   }
 
-  LLDB_LOG(log, "continued process {0}", m_continue_process->GetID());
+  assert(thread_actions.size() >= 1);
+  if (thread_actions.size() > 1)
+    return SendIllFormedResponse(
+        packet, "Resuming multiple processes not supported yet");
+
+  for (std::pair<lldb::pid_t, ResumeActionList> x : thread_actions) {
+    auto process_it = m_debugged_processes.find(x.first);
+    if (process_it == m_debugged_processes.end()) {
+      LLDB_LOG(log, "vCont failed for process {0}: process not debugged",
+               x.first);
+      return SendErrorResponse(GDBRemoteServerError::eErrorResume);
+    }
+
+    Status error = process_it->second->Resume(x.second);
+    if (error.Fail()) {
+      LLDB_LOG(log, "vCont failed for process {0}: {1}", x.first, error);
+      return SendErrorResponse(GDBRemoteServerError::eErrorResume);
+    }
+
+    LLDB_LOG(log, "continued process {0}", x.first);
+  }
 
   return SendContinueSuccessResponse();
 }
@@ -4011,38 +4030,6 @@ std::string GDBRemoteCommunicationServerLLGS::XMLEncodeAttributeValue(
   return result;
 }
 
-llvm::Expected<lldb::tid_t> GDBRemoteCommunicationServerLLGS::ReadTid(
-    StringExtractorGDBRemote &packet, bool allow_all, lldb::pid_t default_pid) {
-  assert(m_current_process);
-  assert(m_current_process->GetID() != LLDB_INVALID_PROCESS_ID);
-
-  auto pid_tid = packet.GetPidTid(default_pid);
-  if (!pid_tid)
-    return llvm::make_error<StringError>(inconvertibleErrorCode(),
-                                         "Malformed thread-id");
-
-  lldb::pid_t pid = pid_tid->first;
-  lldb::tid_t tid = pid_tid->second;
-
-  if (!allow_all && pid == StringExtractorGDBRemote::AllProcesses)
-    return llvm::make_error<StringError>(
-        inconvertibleErrorCode(),
-        llvm::formatv("PID value {0} not allowed", pid == 0 ? 0 : -1));
-
-  if (!allow_all && tid == StringExtractorGDBRemote::AllThreads)
-    return llvm::make_error<StringError>(
-        inconvertibleErrorCode(),
-        llvm::formatv("TID value {0} not allowed", tid == 0 ? 0 : -1));
-
-  if (pid != StringExtractorGDBRemote::AllProcesses) {
-    if (pid != m_current_process->GetID())
-      return llvm::make_error<StringError>(
-          inconvertibleErrorCode(), llvm::formatv("PID {0} not debugged", pid));
-  }
-
-  return tid;
-}
-
 std::vector<std::string> GDBRemoteCommunicationServerLLGS::HandleFeatures(
     const llvm::ArrayRef<llvm::StringRef> client_features) {
   std::vector<std::string> ret =