[lldb-dap] Specify the executable path in the attach info (llvm#138557)

Currently, we are only using the executable name when attaching. The
AttachRequestHandler isn't setting the path in the attach info, which
means that we rely on the target when attaching by name. When wo go down
this path, we only look at the executable's filename, not its full path.
Since we know the full path from the attach arguments, we should specify
it in the attach info.

Fixes llvm#138197

Author: JDevlieghere

lldb/tools/lldb-dap/Handler/AttachRequestHandler.cpp

@@ -49,7 +49,6 @@ void AttachRequestHandler::operator()(const llvm::json::Object &request) const {
   llvm::json::Object response;
   lldb::SBError error;
   FillResponse(request, response);
-  lldb::SBAttachInfo attach_info;
   const int invalid_port = 0;
   const auto *arguments = request.getObject("arguments");
   const lldb::pid_t pid =
@@ -58,10 +57,7 @@ void AttachRequestHandler::operator()(const llvm::json::Object &request) const {
       GetInteger<uint64_t>(arguments, "gdb-remote-port").value_or(invalid_port);
   const auto gdb_remote_hostname =
       GetString(arguments, "gdb-remote-hostname").value_or("localhost");
-  if (pid != LLDB_INVALID_PROCESS_ID)
-    attach_info.SetProcessID(pid);
   const auto wait_for = GetBoolean(arguments, "waitFor").value_or(false);
-  attach_info.SetWaitForLaunch(wait_for, false /*async*/);
   dap.configuration.initCommands = GetStrings(arguments, "initCommands");
   dap.configuration.preRunCommands = GetStrings(arguments, "preRunCommands");
   dap.configuration.postRunCommands = GetStrings(arguments, "postRunCommands");
@@ -161,7 +157,13 @@ void AttachRequestHandler::operator()(const llvm::json::Object &request) const {
         dap.target.ConnectRemote(listener, connect_url.c_str(), "gdb-remote",
                                  error);
       } else {
-        // Attach by process name or id.
+        // Attach by pid or process name.
+        lldb::SBAttachInfo attach_info;
+        if (pid != LLDB_INVALID_PROCESS_ID)
+          attach_info.SetProcessID(pid);
+        else if (dap.configuration.program.has_value())
+          attach_info.SetExecutable(dap.configuration.program->data());
+        attach_info.SetWaitForLaunch(wait_for, false /*async*/);
         dap.target.Attach(attach_info, error);
       }
     } else {