[lldb] move the frame index completion into a common completion and apply it to `thread backtrace -s`

Commands frame select and thread backtrace -s can be completed in the same way.
Moved the dedicated completion of frame select into a common completion and
apply it to the both commands, along with the test modified.

lldb/include/lldb/Interpreter/CommandCompletions.h

@@ -39,10 +39,11 @@ public:
     eProcessPluginCompletion = (1u << 11),
     eDisassemblyFlavorCompletion = (1u << 12),
     eTypeLanguageCompletion = (1u << 13),
+    eFrameIndexCompletion = (1u << 14),
     // This item serves two purposes.  It is the last element in the enum, so
     // you can add custom enums starting from here in your Option class. Also
     // if you & in this bit the base code will not process the option.
-    eCustomCompletion = (1u << 14)
+    eCustomCompletion = (1u << 15)
   };
 
   static bool InvokeCommonCompletionCallbacks(
@@ -103,6 +104,9 @@ public:
 
   static void TypeLanguages(CommandInterpreter &interpreter,
                             CompletionRequest &request, SearchFilter *searcher);
+
+  static void FrameIndexes(CommandInterpreter &interpreter,
+                           CompletionRequest &request, SearchFilter *searcher);
 };
 
 } // namespace lldb_private

lldb/source/Commands/CommandCompletions.cpp

@@ -20,6 +20,7 @@
 #include "lldb/Symbol/Variable.h"
 #include "lldb/Target/Language.h"
 #include "lldb/Target/RegisterContext.h"
+#include "lldb/Target/Thread.h"
 #include "lldb/Utility/FileSpec.h"
 #include "lldb/Utility/StreamString.h"
 #include "lldb/Utility/TildeExpressionResolver.h"
@@ -62,6 +63,7 @@ bool CommandCompletions::InvokeCommonCompletionCallbacks(
       {eProcessPluginCompletion, CommandCompletions::ProcessPluginNames},
       {eDisassemblyFlavorCompletion, CommandCompletions::DisassemblyFlavors},
       {eTypeLanguageCompletion, CommandCompletions::TypeLanguages},
+      {eFrameIndexCompletion, CommandCompletions::FrameIndexes},
       {eNoCompletion, nullptr} // This one has to be last in the list.
   };
 
@@ -618,3 +620,20 @@ void CommandCompletions::TypeLanguages(CommandInterpreter &interpreter,
         Language::GetNameForLanguageType(static_cast<lldb::LanguageType>(bit)));
   }
 }
+
+void CommandCompletions::FrameIndexes(CommandInterpreter &interpreter,
+                                      CompletionRequest &request,
+                                      SearchFilter *searcher) {
+  const ExecutionContext &exe_ctx = interpreter.GetExecutionContext();
+  if (!exe_ctx.HasProcessScope())
+    return;
+
+  lldb::ThreadSP thread_sp = exe_ctx.GetThreadSP();
+  const uint32_t frame_num = thread_sp->GetStackFrameCount();
+  for (uint32_t i = 0; i < frame_num; ++i) {
+    lldb::StackFrameSP frame_sp = thread_sp->GetStackFrameAtIndex(i);
+    StreamString strm;
+    frame_sp->Dump(&strm, false, true);
+    request.TryCompleteCurrentArg(std::to_string(i), strm.GetString());
+  }
+}

lldb/source/Commands/CommandObjectFrame.cpp

@@ -291,17 +291,12 @@ public:
   void
   HandleArgumentCompletion(CompletionRequest &request,
                            OptionElementVector &opt_element_vector) override {
-    if (!m_exe_ctx.HasProcessScope() || request.GetCursorIndex() != 0)
+    if (request.GetCursorIndex() != 0)
       return;
 
-    lldb::ThreadSP thread_sp = m_exe_ctx.GetThreadSP();
-    const uint32_t frame_num = thread_sp->GetStackFrameCount();
-    for (uint32_t i = 0; i < frame_num; ++i) {
-      lldb::StackFrameSP frame_sp = thread_sp->GetStackFrameAtIndex(i);
-      StreamString strm;
-      frame_sp->Dump(&strm, false, true);
-      request.TryCompleteCurrentArg(std::to_string(i), strm.GetString());
-    }
+    CommandCompletions::InvokeCommonCompletionCallbacks(
+        GetCommandInterpreter(), CommandCompletions::eFrameIndexCompletion,
+        request, nullptr);
   }
 
   Options *GetOptions() override { return &m_options; }

lldb/source/Interpreter/CommandObject.cpp

@@ -1055,7 +1055,7 @@ CommandObject::ArgumentTableEntry CommandObject::g_arguments_data[] = {
     { eArgTypeExprFormat, "expression-format", CommandCompletions::eNoCompletion, { nullptr, false }, "[ [bool|b] | [bin] | [char|c] | [oct|o] | [dec|i|d|u] | [hex|x] | [float|f] | [cstr|s] ]" },
     { eArgTypeFilename, "filename", CommandCompletions::eDiskFileCompletion, { nullptr, false }, "The name of a file (can include path)." },
     { eArgTypeFormat, "format", CommandCompletions::eNoCompletion, { FormatHelpTextCallback, true }, nullptr },
-    { eArgTypeFrameIndex, "frame-index", CommandCompletions::eNoCompletion, { nullptr, false }, "Index into a thread's list of frames." },
+    { eArgTypeFrameIndex, "frame-index", CommandCompletions::eFrameIndexCompletion, { nullptr, false }, "Index into a thread's list of frames." },
     { eArgTypeFullName, "fullname", CommandCompletions::eNoCompletion, { nullptr, false }, "Help text goes here." },
     { eArgTypeFunctionName, "function-name", CommandCompletions::eNoCompletion, { nullptr, false }, "The name of a function." },
     { eArgTypeFunctionOrSymbol, "function-or-symbol", CommandCompletions::eNoCompletion, { nullptr, false }, "The name of a function or symbol." },

lldb/test/API/functionalities/completion/TestCompletion.py

@@ -460,12 +460,12 @@ class CommandLineCompletionTestCase(TestBase):
         self.check_completion_with_desc("breakpoint set --Z", [
         ])
 
-    def test_frame_select(self):
+    def test_common_completion_frame_index(self):
         self.build()
-        self.main_source_spec = lldb.SBFileSpec("main.cpp")
-        lldbutil.run_to_source_breakpoint(self, '// Break here', self.main_source_spec)
+        lldbutil.run_to_source_breakpoint(self, '// Break here', lldb.SBFileSpec("main.cpp"))
 
         self.complete_from_to('frame select ', ['0'])
+        self.complete_from_to('thread backtrace -s ', ['0'])
     
     def test_frame_recognizer_delete(self):
         self.runCmd("frame recognizer add -l py_class -s module_name -n recognizer_name")