[lldb] add a marker before skipped frames

lldb/include/lldb/Host/Terminal.h

@@ -68,6 +68,18 @@ class Terminal {
 
   llvm::Error SetHardwareFlowControl(bool enabled);
 
+  /// Returns whether or not the current terminal supports Unicode rendering.
+  ///
+  /// The value is cached after the first computation.
+  ///
+  /// On POSIX systems, we check if the LANG environment variable contains the
+  /// substring "UTF-8", case insensitive.
+  ///
+  /// On Windows, we always return true since we use the `WriteConsoleW` API
+  /// internally. Note that the default Windows codepage (437) does not support
+  /// all Unicode characters. This function does not check the codepage.
+  static bool SupportsUnicode();
+
 protected:
   struct Data;
 

lldb/include/lldb/Host/common/DiagnosticsRendering.h

@@ -64,6 +64,17 @@ void RenderDiagnosticDetails(Stream &stream,
                              bool show_inline,
                              llvm::ArrayRef<DiagnosticDetail> details);
 
+/// Returns whether or not the current terminal supports Unicode rendering.
+///
+/// The value is cached after the first computation.
+///
+/// On POSIX systems, we check if the LANG environment variable contains the
+/// substring "UTF-8";
+///
+/// On Windows, we check that we are running from the Windows Terminal
+/// application.
+bool TerminalSupportsUnicode();
+
 class DiagnosticError
     : public llvm::ErrorInfo<DiagnosticError, CloneableECError> {
 public:

lldb/include/lldb/Target/StackFrame.h

@@ -354,7 +354,7 @@ class StackFrame : public ExecutionContextScope,
   /// \param [in] frame_marker
   ///   Optional string that will be prepended to the frame output description.
   void DumpUsingSettingsFormat(Stream *strm, bool show_unique = false,
-                               const char *frame_marker = nullptr);
+                               llvm::StringRef frame_marker = "");
 
   /// Print a description for this frame using a default format.
   ///
@@ -390,7 +390,7 @@ class StackFrame : public ExecutionContextScope,
   /// \return
   ///   Returns true if successful.
   bool GetStatus(Stream &strm, bool show_frame_info, bool show_source,
-                 bool show_unique = false, const char *frame_marker = nullptr);
+                 bool show_unique = false, llvm::StringRef frame_marker = "");
 
   /// Query whether this frame is a concrete frame on the call stack, or if it
   /// is an inlined frame derived from the debug information and presented by

lldb/include/lldb/Target/StackFrameList.h

@@ -49,6 +49,15 @@ class StackFrameList {
   /// Resets the selected frame index of this object.
   void ClearSelectedFrameIndex();
 
+  /// Return \code true if the next frame is hidden.
+  bool IsNextFrameHidden(lldb_private::StackFrame &frame);
+
+  /// Return \code true if the previous frame is hidden.
+  bool IsPreviousFrameHidden(lldb_private::StackFrame &frame);
+
+  std::wstring FrameMarker(lldb::StackFrameSP frame_sp,
+                           lldb::StackFrameSP selected_frame_sp);
+
   /// Get the currently selected frame index.
   /// We should only call SelectMostRelevantFrame if (a) the user hasn't already
   /// selected a frame, and (b) if this really is a user facing
@@ -96,7 +105,7 @@ class StackFrameList {
   size_t GetStatus(Stream &strm, uint32_t first_frame, uint32_t num_frames,
                    bool show_frame_info, uint32_t num_frames_with_source,
                    bool show_unique = false, bool show_hidden = false,
-                   const char *frame_marker = nullptr);
+                   bool show_selected_frame = false);
 
   /// Returns whether we have currently fetched all the frames of a stack.
   bool WereAllFramesFetched() const;

lldb/source/Host/common/DiagnosticsRendering.cpp

@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "lldb/Host/common/DiagnosticsRendering.h"
+#include "lldb/Host/Terminal.h"
 #include <cstdint>
 
 using namespace lldb_private;
@@ -102,7 +103,7 @@ void RenderDiagnosticDetails(Stream &stream,
   // characters.  In the future it might make sense to move this into
   // Host so it can be customized for a specific platform.
   llvm::StringRef cursor, underline, vbar, joint, hbar, spacer;
-  if (stream.AsRawOstream().colors_enabled()) {
+  if (Terminal::SupportsUnicode()) {
     cursor = "˄";
     underline = "˜";
     vbar = "│";
@@ -231,5 +232,4 @@ void RenderDiagnosticDetails(Stream &stream,
       stream << detail.rendered << '\n';
     }
 }
-
 } // namespace lldb_private

lldb/source/Host/common/Terminal.cpp

@@ -400,6 +400,21 @@ llvm::Error Terminal::SetHardwareFlowControl(bool enabled) {
 #endif // LLDB_ENABLE_TERMIOS
 }
 
+bool Terminal::SupportsUnicode() {
+  static std::optional<bool> result;
+  if (result)
+    return result.value();
+#ifdef _WIN32
+  return true;
+#else
+  const char *lang_var = std::getenv("LANG");
+  if (!lang_var)
+    return false;
+  result = llvm::StringRef(lang_var).lower().find("utf-8") != std::string::npos;
+#endif
+  return result.value();
+}
+
 TerminalState::TerminalState(Terminal term, bool save_process_group)
     : m_tty(term) {
   Save(term, save_process_group);

lldb/source/Target/StackFrame.cpp

@@ -1935,7 +1935,7 @@ bool StackFrame::DumpUsingFormat(Stream &strm,
 }
 
 void StackFrame::DumpUsingSettingsFormat(Stream *strm, bool show_unique,
-                                         const char *frame_marker) {
+                                         llvm::StringRef frame_marker) {
   if (strm == nullptr)
     return;
 
@@ -1953,6 +1953,7 @@ void StackFrame::DumpUsingSettingsFormat(Stream *strm, bool show_unique,
       frame_format = &format_entry;
     }
   }
+
   if (!DumpUsingFormat(*strm, frame_format, frame_marker)) {
     Dump(strm, true, false);
     strm->EOL();
@@ -2034,7 +2035,7 @@ bool StackFrame::HasCachedData() const {
 }
 
 bool StackFrame::GetStatus(Stream &strm, bool show_frame_info, bool show_source,
-                           bool show_unique, const char *frame_marker) {
+                           bool show_unique, llvm::StringRef frame_marker) {
   if (show_frame_info) {
     strm.Indent();
     DumpUsingSettingsFormat(&strm, show_unique, frame_marker);

lldb/source/Target/StackFrameList.cpp

@@ -26,6 +26,7 @@
 #include "lldb/Utility/LLDBLog.h"
 #include "lldb/Utility/Log.h"
 #include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/Support/ConvertUTF.h"
 
 #include <memory>
 
@@ -879,11 +880,42 @@ StackFrameList::GetStackFrameSPForStackFramePtr(StackFrame *stack_frame_ptr) {
   return ret_sp;
 }
 
+bool StackFrameList::IsNextFrameHidden(lldb_private::StackFrame &frame) {
+  uint32_t frame_idx = frame.GetFrameIndex();
+  StackFrameSP frame_sp = GetFrameAtIndex(frame_idx + 1);
+  if (!frame_sp)
+    return false;
+  return frame_sp->IsHidden();
+}
+
+bool StackFrameList::IsPreviousFrameHidden(lldb_private::StackFrame &frame) {
+  uint32_t frame_idx = frame.GetFrameIndex();
+  if (frame_idx == 0)
+    return false;
+  StackFrameSP frame_sp = GetFrameAtIndex(frame_idx - 1);
+  if (!frame_sp)
+    return false;
+  return frame_sp->IsHidden();
+}
+
+std::wstring StackFrameList::FrameMarker(lldb::StackFrameSP frame_sp,
+                                         lldb::StackFrameSP selected_frame_sp) {
+  if (frame_sp == selected_frame_sp)
+    return Terminal::SupportsUnicode() ? L" * " : L"* ";
+  else if (!Terminal::SupportsUnicode())
+    return L"  ";
+  else if (IsPreviousFrameHidden(*frame_sp))
+    return L" ﹉";
+  else if (IsNextFrameHidden(*frame_sp))
+    return L" ﹍";
+  return L" 　";
+}
+
 size_t StackFrameList::GetStatus(Stream &strm, uint32_t first_frame,
                                  uint32_t num_frames, bool show_frame_info,
                                  uint32_t num_frames_with_source,
                                  bool show_unique, bool show_hidden,
-                                 const char *selected_frame_marker) {
+                                 bool show_selected_frame) {
   size_t num_frames_displayed = 0;
 
   if (num_frames == 0)
@@ -901,25 +933,17 @@ size_t StackFrameList::GetStatus(Stream &strm, uint32_t first_frame,
 
   StackFrameSP selected_frame_sp =
       m_thread.GetSelectedFrame(DoNoSelectMostRelevantFrame);
-  const char *unselected_marker = nullptr;
   std::string buffer;
-  if (selected_frame_marker) {
-    size_t len = strlen(selected_frame_marker);
-    buffer.insert(buffer.begin(), len, ' ');
-    unselected_marker = buffer.c_str();
-  }
-  const char *marker = nullptr;
+  std::wstring marker;
   for (frame_idx = first_frame; frame_idx < last_frame; ++frame_idx) {
     frame_sp = GetFrameAtIndex(frame_idx);
     if (!frame_sp)
       break;
 
-    if (selected_frame_marker != nullptr) {
-      if (frame_sp == selected_frame_sp)
-        marker = selected_frame_marker;
-      else
-        marker = unselected_marker;
-    }
+    if (show_selected_frame)
+      marker = FrameMarker(frame_sp, selected_frame_sp);
+    else
+      marker = FrameMarker(frame_sp, nullptr);
 
     // Hide uninteresting frames unless it's the selected frame.
     if (!show_hidden && frame_sp != selected_frame_sp && frame_sp->IsHidden())
@@ -933,10 +957,11 @@ size_t StackFrameList::GetStatus(Stream &strm, uint32_t first_frame,
             m_thread.GetID(), num_frames_displayed))
       break;
 
-
+    std::string marker_utf8;
+    llvm::convertWideToUTF8(marker, marker_utf8);
     if (!frame_sp->GetStatus(strm, show_frame_info,
                              num_frames_with_source > (first_frame - frame_idx),
-                             show_unique, marker))
+                             show_unique, marker_utf8))
       break;
     ++num_frames_displayed;
   }

lldb/source/Target/Thread.cpp

@@ -1817,16 +1817,16 @@ size_t Thread::GetStatus(Stream &strm, uint32_t start_frame,
 
     const bool show_frame_info = true;
     const bool show_frame_unique = only_stacks;
-    const char *selected_frame_marker = nullptr;
+    bool show_selected_frame = false;
     if (num_frames == 1 || only_stacks ||
         (GetID() != GetProcess()->GetThreadList().GetSelectedThread()->GetID()))
       strm.IndentMore();
     else
-      selected_frame_marker = "* ";
+      show_selected_frame = true;
 
     num_frames_shown = GetStackFrameList()->GetStatus(
         strm, start_frame, num_frames, show_frame_info, num_frames_with_source,
-        show_frame_unique, show_hidden, selected_frame_marker);
+        show_frame_unique, show_hidden, show_selected_frame);
     if (num_frames == 1)
       strm.IndentLess();
     strm.IndentLess();