[clang] [llvm] Alisonz/tmp1 (PR #205163)

[Alison Zhang via cfe-commits]

================
@@ -913,20 +912,28 @@ CompilerInstance::createOutputFileImpl(StringRef OutputPath, bool Binary,
 // Initialization Utilities
 
 bool CompilerInstance::InitializeSourceManager(const FrontendInputFile &Input){
-  // Retrieve the converter to the internal charset if it exists.
-  llvm::TextEncodingConverter *Converter =
-      hasPreprocessor() ? getPreprocessor().getTextEncoding().getConverter(
-                              CA_FromInputEncoding)
-                        : nullptr;
-
-  return InitializeSourceManager(Input, Converter, getDiagnostics(),
-                                 getFileManager(), getSourceManager());
+  // Get the input encoding and add converter to cache if specified
+  std::string InputEncoding;
+  if (hasPreprocessor()) {
+    InputEncoding = getLangOpts().InputEncoding;
+    if (!InputEncoding.empty()) {
+      // Add the converter to SourceManager's cache
+      auto ConverterOrErr = getSourceManager().getOrCreateConverter(InputEncoding, "UTF-8");
+      // If converter creation fails, the error will be reported when createFileID tries to use it
+      (void)ConverterOrErr;
+    }
+  }
+  
+  return InitializeSourceManager(Input, getDiagnostics(),
+                                 getFileManager(), getSourceManager(),
+                                 InputEncoding);
----------------
azhan92 wrote:

Change InputEncoding to

```
hasPreprocessor() ? llvm::StringRef(getLangOpts().InputEncoding) : llvm::StringRef()
```

https://github.com/llvm/llvm-project/pull/205163