Only recompute the symbol/execution context on process state change

Author: JDevlieghere

lldb/include/lldb/Core/Statusline.h

@@ -9,6 +9,8 @@
 #ifndef LLDB_CORE_STATUSLINE_H
 #define LLDB_CORE_STATUSLINE_H
 
+#include "lldb/Symbol/SymbolContext.h"
+#include "lldb/Target/ExecutionContext.h"
 #include "lldb/lldb-forward.h"
 #include <cstdint>
 #include <string>
@@ -46,7 +48,8 @@ class Statusline {
   void UpdateScrollWindow(ScrollWindowMode mode);
 
   Debugger &m_debugger;
-  std::string m_last_str;
+  ExecutionContext m_exe_ctx;
+  SymbolContext m_symbol_ctx;
   uint64_t m_terminal_width = 0;
   uint64_t m_terminal_height = 0;
 };

lldb/source/Core/Debugger.cpp

@@ -2149,13 +2149,16 @@ lldb::thread_result_t Debugger::DefaultEventHandler() {
   while (!done) {
     EventSP event_sp;
     if (listener_sp->GetEvent(event_sp, std::nullopt)) {
+      bool update_statusline = false;
       if (event_sp) {
         Broadcaster *broadcaster = event_sp->GetBroadcaster();
         if (broadcaster) {
           uint32_t event_type = event_sp->GetType();
           ConstString broadcaster_class(broadcaster->GetBroadcasterClass());
           if (broadcaster_class == broadcaster_class_process) {
             HandleProcessEvent(event_sp);
+            update_statusline =
+                (event_type & Process::eBroadcastBitStateChanged) != 0;
           } else if (broadcaster_class == broadcaster_class_target) {
             if (Breakpoint::BreakpointEventData::GetEventDataFromEvent(
                     event_sp.get())) {
@@ -2200,7 +2203,7 @@ lldb::thread_result_t Debugger::DefaultEventHandler() {
         if (m_forward_listener_sp)
           m_forward_listener_sp->AddEvent(event_sp);
       }
-      RedrawStatusline();
+      RedrawStatusline(update_statusline);
     }
   }
 

lldb/source/Core/Statusline.cpp

@@ -70,8 +70,6 @@ void Statusline::Draw(std::string str) {
   if (!stream_sp)
     return;
 
-  m_last_str = str;
-
   str = ansi::TrimAndPad(str, m_terminal_width);
 
   LockedStreamFile locked_stream = stream_sp->Lock();
@@ -130,15 +128,16 @@ void Statusline::UpdateScrollWindow(ScrollWindowMode mode) {
 
 void Statusline::Redraw(const ExecutionContext *exe_ctx,
                         const SymbolContext *sym_ctx) {
-  if (!exe_ctx && !sym_ctx) {
-    Draw(m_last_str);
-    return;
-  }
+  if (exe_ctx)
+    m_exe_ctx = *exe_ctx;
+
+  if (sym_ctx)
+    m_symbol_ctx = *sym_ctx;
 
   StreamString stream;
   FormatEntity::Entry format = m_debugger.GetStatuslineFormat();
-  FormatEntity::Format(format, stream, sym_ctx, exe_ctx, nullptr, nullptr,
-                       false, false);
+  FormatEntity::Format(format, stream, &m_symbol_ctx, &m_exe_ctx, nullptr,
+                       nullptr, false, false);
 
   Draw(stream.GetString().str());
 }