[clang] Hide the LangOptions pointer from CompilerInvocation (llvm#137675)

This PR makes `CompilerInvocation` the sole owner of the `LangOptions`
instance.

Author: jansvoboda11

clang/include/clang/Frontend/ASTUnit.h

@@ -106,7 +106,7 @@ class ASTUnit {
   };
 
 private:
-  std::shared_ptr<LangOptions>            LangOpts;
+  std::unique_ptr<LangOptions> LangOpts;
   IntrusiveRefCntPtr<DiagnosticsEngine>   Diagnostics;
   IntrusiveRefCntPtr<FileManager>         FileMgr;
   IntrusiveRefCntPtr<SourceManager>       SourceMgr;
@@ -698,19 +698,17 @@ class ASTUnit {
   /// lifetime is expected to extend past that of the returned ASTUnit.
   ///
   /// \returns - The initialized ASTUnit or null if the AST failed to load.
-  static std::unique_ptr<ASTUnit>
-  LoadFromASTFile(StringRef Filename, const PCHContainerReader &PCHContainerRdr,
-                  WhatToLoad ToLoad,
-                  IntrusiveRefCntPtr<DiagnosticsEngine> Diags,
-                  const FileSystemOptions &FileSystemOpts,
-                  const HeaderSearchOptions &HSOpts,
-                  std::shared_ptr<LangOptions> LangOpts = nullptr,
-                  bool OnlyLocalDecls = false,
-                  CaptureDiagsKind CaptureDiagnostics = CaptureDiagsKind::None,
-                  bool AllowASTWithCompilerErrors = false,
-                  bool UserFilesAreVolatile = false,
-                  IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS =
-                      llvm::vfs::getRealFileSystem());
+  static std::unique_ptr<ASTUnit> LoadFromASTFile(
+      StringRef Filename, const PCHContainerReader &PCHContainerRdr,
+      WhatToLoad ToLoad, IntrusiveRefCntPtr<DiagnosticsEngine> Diags,
+      const FileSystemOptions &FileSystemOpts,
+      const HeaderSearchOptions &HSOpts, const LangOptions *LangOpts = nullptr,
+      bool OnlyLocalDecls = false,
+      CaptureDiagsKind CaptureDiagnostics = CaptureDiagsKind::None,
+      bool AllowASTWithCompilerErrors = false,
+      bool UserFilesAreVolatile = false,
+      IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS =
+          llvm::vfs::getRealFileSystem());
 
 private:
   /// Helper function for \c LoadFromCompilerInvocation() and

clang/include/clang/Frontend/CompilerInstance.h

@@ -327,9 +327,6 @@ class CompilerInstance : public ModuleLoader {
 
   LangOptions &getLangOpts() { return Invocation->getLangOpts(); }
   const LangOptions &getLangOpts() const { return Invocation->getLangOpts(); }
-  std::shared_ptr<LangOptions> getLangOptsPtr() const {
-    return Invocation->getLangOptsPtr();
-  }
 
   PreprocessorOptions &getPreprocessorOpts() {
     return Invocation->getPreprocessorOpts();

clang/include/clang/Frontend/CompilerInvocation.h

@@ -265,12 +265,6 @@ class CompilerInvocation : public CompilerInvocationBase {
   }
   /// @}
 
-  /// Base class internals.
-  /// @{
-  using CompilerInvocationBase::LangOpts;
-  std::shared_ptr<LangOptions> getLangOptsPtr() { return LangOpts; }
-  /// @}
-
   /// Create a compiler invocation from a list of input options.
   /// \returns true on success.
   ///

clang/lib/Frontend/ASTUnit.cpp

@@ -805,7 +805,7 @@ std::unique_ptr<ASTUnit> ASTUnit::LoadFromASTFile(
     StringRef Filename, const PCHContainerReader &PCHContainerRdr,
     WhatToLoad ToLoad, IntrusiveRefCntPtr<DiagnosticsEngine> Diags,
     const FileSystemOptions &FileSystemOpts, const HeaderSearchOptions &HSOpts,
-    std::shared_ptr<LangOptions> LangOpts, bool OnlyLocalDecls,
+    const LangOptions *LangOpts, bool OnlyLocalDecls,
     CaptureDiagsKind CaptureDiagnostics, bool AllowASTWithCompilerErrors,
     bool UserFilesAreVolatile, IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS) {
   std::unique_ptr<ASTUnit> AST(new ASTUnit(true));
@@ -819,7 +819,8 @@ std::unique_ptr<ASTUnit> ASTUnit::LoadFromASTFile(
 
   ConfigureDiags(Diags, *AST, CaptureDiagnostics);
 
-  AST->LangOpts = LangOpts ? LangOpts : std::make_shared<LangOptions>();
+  AST->LangOpts = LangOpts ? std::make_unique<LangOptions>(*LangOpts)
+                           : std::make_unique<LangOptions>();
   AST->OnlyLocalDecls = OnlyLocalDecls;
   AST->CaptureDiagnostics = CaptureDiagnostics;
   AST->Diagnostics = Diags;
@@ -1211,7 +1212,8 @@ bool ASTUnit::Parse(std::shared_ptr<PCHContainerOperations> PCHContainerOps,
          "IR inputs not support here!");
 
   // Configure the various subsystems.
-  LangOpts = Clang->getInvocation().LangOpts;
+  LangOpts =
+      std::make_unique<LangOptions>(Clang->getInvocation().getLangOpts());
   FileSystemOpts = Clang->getFileSystemOpts();
 
   ResetForParse();
@@ -1486,7 +1488,7 @@ void ASTUnit::transferASTDataFromCompilerInstance(CompilerInstance &CI) {
   // Steal the created target, context, and preprocessor if they have been
   // created.
   assert(CI.hasInvocation() && "missing invocation");
-  LangOpts = CI.getInvocation().LangOpts;
+  LangOpts = std::make_unique<LangOptions>(CI.getInvocation().getLangOpts());
   TheSema = CI.takeSema();
   Consumer = CI.takeASTConsumer();
   if (CI.hasASTContext())

clang/lib/Frontend/FrontendAction.cpp

@@ -847,7 +847,7 @@ bool FrontendAction::BeginSourceFile(CompilerInstance &CI,
 
     std::unique_ptr<ASTUnit> AST = ASTUnit::LoadFromASTFile(
         InputFile, CI.getPCHContainerReader(), ASTUnit::LoadEverything, Diags,
-        CI.getFileSystemOpts(), CI.getHeaderSearchOpts(), CI.getLangOptsPtr());
+        CI.getFileSystemOpts(), CI.getHeaderSearchOpts(), &CI.getLangOpts());
 
     if (!AST)
       return false;