[Lldb-commits] [lldb] [windows][lldb] force the console to use a UTF-8 codepage (PR #149493)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-lldb

Author: Charles Zablit (charles-zablit)

<details>
<summary>Changes</summary>

This patch sets the codepage of the parent Windows console to `utf-8` and resets it back to the original codepage once `lldb` exits.

This fixes a rendering issue where the characters defined in `DiagnosticsRendering.cpp` (`"╰"` for instance) are not rendered properly on Windows out of the box, because the default codepage is not `utf-8`.

This solution is based on this [SO thread](https://stackoverflow.com/questions/10882277/properly-print-utf8-characters-in-windows-console) and [this patch downstream](https://github.com/swiftlang/swift/pull/40632/files#diff-e948e4bd7a601e3ca82d596058ccb39326459a4751470eec4d393adeaf516977R37-R38).

rdar://156064500

---
Full diff: https://github.com/llvm/llvm-project/pull/149493.diff


2 Files Affected:

- (modified) lldb/source/Plugins/Platform/Windows/PlatformWindows.cpp (+20) 
- (modified) lldb/source/Plugins/Platform/Windows/PlatformWindows.h (+8) 


``````````diff
diff --git a/lldb/source/Plugins/Platform/Windows/PlatformWindows.cpp b/lldb/source/Plugins/Platform/Windows/PlatformWindows.cpp
index c0c26cc5f1954..d3e981de81313 100644
--- a/lldb/source/Plugins/Platform/Windows/PlatformWindows.cpp
+++ b/lldb/source/Plugins/Platform/Windows/PlatformWindows.cpp
@@ -41,6 +41,10 @@ LLDB_PLUGIN_DEFINE(PlatformWindows)
 
 static uint32_t g_initialize_count = 0;
 
+#if defined(_WIN32)
+std::optional<UINT> g_prev_console_cp = std::nullopt;
+#endif
+
 PlatformSP PlatformWindows::CreateInstance(bool force,
                                            const lldb_private::ArchSpec *arch) {
   // The only time we create an instance is when we are creating a remote
@@ -98,6 +102,7 @@ void PlatformWindows::Initialize() {
     default_platform_sp->SetSystemArchitecture(HostInfo::GetArchitecture());
     Platform::SetHostPlatform(default_platform_sp);
 #endif
+    SetConsoleCodePage();
     PluginManager::RegisterPlugin(
         PlatformWindows::GetPluginNameStatic(false),
         PlatformWindows::GetPluginDescriptionStatic(false),
@@ -108,6 +113,7 @@ void PlatformWindows::Initialize() {
 void PlatformWindows::Terminate() {
   if (g_initialize_count > 0) {
     if (--g_initialize_count == 0) {
+      ResetConsoleCodePage();
       PluginManager::UnregisterPlugin(PlatformWindows::CreateInstance);
     }
   }
@@ -808,3 +814,17 @@ extern "C" {
 
   return Status();
 }
+
+void PlatformWindows::SetConsoleCodePage() {
+  #if defined(_WIN32)
+    g_prev_console_cp = GetConsoleOutputCP();
+    SetConsoleOutputCP(CP_UTF8);
+  #endif
+}
+
+void PlatformWindows::ResetConsoleCodePage() {
+  #if defined(_WIN32)
+  if (g_prev_console_cp)
+    SetConsoleOutputCP(*g_prev_console_cp);
+  #endif
+}
diff --git a/lldb/source/Plugins/Platform/Windows/PlatformWindows.h b/lldb/source/Plugins/Platform/Windows/PlatformWindows.h
index 771133f341e90..d14aa52e5e1c8 100644
--- a/lldb/source/Plugins/Platform/Windows/PlatformWindows.h
+++ b/lldb/source/Plugins/Platform/Windows/PlatformWindows.h
@@ -80,6 +80,14 @@ class PlatformWindows : public RemoteAwarePlatform {
   size_t GetSoftwareBreakpointTrapOpcode(Target &target,
                                          BreakpointSite *bp_site) override;
 
+  /// Set the current console's code page to UTF-8 and store the previous
+  /// codepage in \a g_prev_console_cp.
+  static void SetConsoleCodePage();
+
+  /// Reset the current console's code page to the value stored
+  /// in \a g_prev_console_cp if any.
+  static void ResetConsoleCodePage();
+
   std::vector<ArchSpec> m_supported_architectures;
 
 private:

``````````

</details>


https://github.com/llvm/llvm-project/pull/149493