[lldb] Make repeat commands work for regex commands

Fix logic for repeat commands, so that regex commands (specificially `bt`) are
given the opportunity to provide a repeat command.

rdar://104562616

Differential Revision: https://reviews.llvm.org/D143695

(cherry picked from commit 5e0ee1b)

Author: kastiglione

lldb/include/lldb/Interpreter/CommandInterpreter.h

@@ -351,7 +351,8 @@ class CommandInterpreter : public Broadcaster,
                      CommandReturnObject &result);
 
   bool HandleCommand(const char *command_line, LazyBool add_to_history,
-                     CommandReturnObject &result);
+                     CommandReturnObject &result,
+                     bool force_repeat_command = false);
 
   bool WasInterrupted() const;
 

lldb/source/Commands/CommandObjectRegexCommand.cpp

@@ -73,8 +73,9 @@ bool CommandObjectRegexCommand::DoExecute(llvm::StringRef command,
         result.GetOutputStream().Printf("%s\n", new_command->c_str());
       // We don't have to pass an override_context here, as the command that 
       // called us should have set up the context appropriately.
-      return m_interpreter.HandleCommand(new_command->c_str(),
-                                         eLazyBoolNo, result);
+      bool force_repeat_command = true;
+      return m_interpreter.HandleCommand(new_command->c_str(), eLazyBoolNo,
+                                         result, force_repeat_command);
     }
   }
   result.SetStatus(eReturnStatusFailed);

lldb/source/Interpreter/CommandInterpreter.cpp

@@ -1885,8 +1885,8 @@ bool CommandInterpreter::HandleCommand(const char *command_line,
 
 bool CommandInterpreter::HandleCommand(const char *command_line,
                                        LazyBool lazy_add_to_history,
-                                       CommandReturnObject &result) {
-
+                                       CommandReturnObject &result,
+                                       bool force_repeat_command) {
   std::string command_string(command_line);
   std::string original_command_string(command_line);
 
@@ -2015,17 +2015,26 @@ bool CommandInterpreter::HandleCommand(const char *command_line,
   // arguments.
 
   if (cmd_obj != nullptr) {
+    bool generate_repeat_command = add_to_history;
     // If we got here when empty_command was true, then this command is a
     // stored "repeat command" which we should give a chance to produce it's
     // repeat command, even though we don't add repeat commands to the history.
-    if (add_to_history || empty_command) {
+    generate_repeat_command |= empty_command;
+    // For `command regex`, the regex command (ex `bt`) is added to history, but
+    // the resolved command (ex `thread backtrace`) is _not_ added to history.
+    // However, the resolved command must be given the opportunity to provide a
+    // repeat command. `force_repeat_command` supports this case.
+    generate_repeat_command |= force_repeat_command;
+    if (generate_repeat_command) {
       Args command_args(command_string);
       llvm::Optional<std::string> repeat_command =
           cmd_obj->GetRepeatCommand(command_args, 0);
-      if (repeat_command)
+      if (repeat_command) {
+        LLDB_LOGF(log, "Repeat command: %s", repeat_command->data());
         m_repeat_command.assign(*repeat_command);
-      else
+      } else {
         m_repeat_command.assign(original_command_string);
+      }
     }
 
     if (add_to_history)

lldb/test/API/functionalities/alias/TestBtAliasRepeat.py

@@ -0,0 +1,19 @@
+import lldb
+from lldbsuite.test.lldbtest import TestBase
+from lldbsuite.test import lldbutil
+
+
+class TestCase(TestBase):
+    def test(self):
+        self.build()
+        lldbutil.run_to_source_breakpoint(self, "return", lldb.SBFileSpec("main.c"))
+
+        # Expect "frame #0" but not "frame #1".
+        self.expect("bt 1", inHistory=True, patterns=["frame #0", "^(?!.*frame #1)"])
+
+        # Run an empty command to run the repeat command for `bt`.
+        # The repeat command for `bt N` lists the subsequent N frames.
+        #
+        # In this case, after printing the frame 0 with `bt 1`, the repeat
+        # command will print "frame #1" (and won't print "frame #0").
+        self.expect("", patterns=["^(?!.*frame #0)", "frame #1"])