[lldb] Support Unicode in the prompt

lldb/include/lldb/Host/Editline.h

@@ -248,9 +248,8 @@ class Editline {
   void SetCurrentLine(int line_index);
 
   /// Determines the width of the prompt in characters.  The width is guaranteed
-  /// to be the same for
-  /// all lines of the current multi-line session.
-  int GetPromptWidth();
+  /// to be the same for all lines of the current multi-line session.
+  size_t GetPromptWidth();
 
   /// Returns true if the underlying EditLine session's keybindings are
   /// Emacs-based, or false if

lldb/packages/Python/lldbsuite/test/lldbpexpect.py

@@ -26,6 +26,7 @@ def launch(
         dimensions=None,
         run_under=None,
         post_spawn=None,
+        encoding=None,
         use_colors=False,
     ):
         logfile = getattr(sys.stdout, "buffer", sys.stdout) if self.TraceOn() else None
@@ -58,6 +59,7 @@ def launch(
             timeout=timeout,
             dimensions=dimensions,
             env=env,
+            encoding=encoding,
         )
         self.child.ptyproc.delayafterclose = timeout / 10
         self.child.ptyproc.delayafterterminate = timeout / 10

lldb/source/Host/common/Editline.cpp

@@ -25,6 +25,7 @@
 #include "lldb/Utility/Timeout.h"
 
 #include "llvm/Support/FileSystem.h"
+#include "llvm/Support/Locale.h"
 #include "llvm/Support/Threading.h"
 
 using namespace lldb_private;
@@ -101,6 +102,10 @@ bool IsOnlySpaces(const EditLineStringType &content) {
   return true;
 }
 
+static size_t ColumnWidth(llvm::StringRef str) {
+  return llvm::sys::locale::columnWidth(str);
+}
+
 static int GetOperation(HistoryOperation op) {
   // The naming used by editline for the history operations is counter
   // intuitive to how it's used in LLDB's editline implementation.
@@ -328,14 +333,16 @@ std::string Editline::PromptForIndex(int line_index) {
   std::string continuation_prompt = prompt;
   if (m_set_continuation_prompt.length() > 0) {
     continuation_prompt = m_set_continuation_prompt;
-
     // Ensure that both prompts are the same length through space padding
-    while (continuation_prompt.length() < prompt.length()) {
-      continuation_prompt += ' ';
-    }
-    while (prompt.length() < continuation_prompt.length()) {
-      prompt += ' ';
-    }
+    const size_t prompt_width = ColumnWidth(prompt);
+    const size_t cont_prompt_width = ColumnWidth(continuation_prompt);
+    const size_t padded_prompt_width =
+        std::max(prompt_width, cont_prompt_width);
+    if (prompt_width < padded_prompt_width)
+      prompt += std::string(padded_prompt_width - prompt_width, ' ');
+    else if (cont_prompt_width < padded_prompt_width)
+      continuation_prompt +=
+          std::string(padded_prompt_width - cont_prompt_width, ' ');
   }
 
   if (use_line_numbers) {
@@ -353,7 +360,7 @@ void Editline::SetCurrentLine(int line_index) {
   m_current_prompt = PromptForIndex(line_index);
 }
 
-int Editline::GetPromptWidth() { return (int)PromptForIndex(0).length(); }
+size_t Editline::GetPromptWidth() { return ColumnWidth(PromptForIndex(0)); }
 
 bool Editline::IsEmacs() {
   const char *editor;
@@ -441,7 +448,7 @@ void Editline::DisplayInput(int firstIndex) {
 int Editline::CountRowsForLine(const EditLineStringType &content) {
   std::string prompt =
       PromptForIndex(0); // Prompt width is constant during an edit session
-  int line_length = (int)(content.length() + prompt.length());
+  int line_length = (int)(content.length() + ColumnWidth(prompt));
   return (line_length / m_terminal_width) + 1;
 }
 

lldb/test/API/terminal/TestEditline.py

@@ -44,3 +44,14 @@ def test_left_right_arrow(self):
             )
 
         self.quit()
+
+    @skipIfAsan
+    @skipIfEditlineSupportMissing
+    def test_prompt_unicode(self):
+        """Test that we can use Unicode in the LLDB prompt."""
+        self.launch(use_colors=True, encoding="utf-8")
+        self.child.send('settings set prompt "🐛 "\n')
+        # Check that the cursor is at position 4 ([4G)
+        # Prompt: 🐛 _
+        # Column: 1..4
+        self.child.expect(re.escape("🐛 \x1b[0m\x1b[4G"))