[Frontend] Teach LoadFromASTFile to take FileName by StringRef (NFC) (#109583)

Without this patch, several callers of LoadFromASTFile construct an
instance of std::string to be passed as FileName, only to be converted
back to StringRef when LoadFromASTFile calls ReadAST.

This patch changes the type of FileName to StringRef and updates the
callers.

Author: kazutakahirata

clang/include/clang/Frontend/ASTUnit.h

@@ -692,8 +692,8 @@ class ASTUnit {
   ///
   /// \returns - The initialized ASTUnit or null if the AST failed to load.
   static std::unique_ptr<ASTUnit>
-  LoadFromASTFile(const std::string &Filename,
-                  const PCHContainerReader &PCHContainerRdr, WhatToLoad ToLoad,
+  LoadFromASTFile(StringRef Filename, const PCHContainerReader &PCHContainerRdr,
+                  WhatToLoad ToLoad,
                   IntrusiveRefCntPtr<DiagnosticsEngine> Diags,
                   const FileSystemOptions &FileSystemOpts,
                   std::shared_ptr<HeaderSearchOptions> HSOpts,

clang/lib/CrossTU/CrossTranslationUnit.cpp

@@ -566,9 +566,9 @@ CrossTranslationUnitContext::ASTLoader::loadFromDump(StringRef ASTDumpPath) {
   IntrusiveRefCntPtr<DiagnosticsEngine> Diags(
       new DiagnosticsEngine(DiagID, &*DiagOpts, DiagClient));
   return ASTUnit::LoadFromASTFile(
-      std::string(ASTDumpPath.str()),
-      CI.getPCHContainerOperations()->getRawReader(), ASTUnit::LoadEverything,
-      Diags, CI.getFileSystemOpts(), CI.getHeaderSearchOptsPtr());
+      ASTDumpPath, CI.getPCHContainerOperations()->getRawReader(),
+      ASTUnit::LoadEverything, Diags, CI.getFileSystemOpts(),
+      CI.getHeaderSearchOptsPtr());
 }
 
 /// Load the AST from a source-file, which is supposed to be located inside the

clang/lib/Frontend/ASTUnit.cpp

@@ -802,7 +802,7 @@ void ASTUnit::ConfigureDiags(IntrusiveRefCntPtr<DiagnosticsEngine> Diags,
 }
 
 std::unique_ptr<ASTUnit> ASTUnit::LoadFromASTFile(
-    const std::string &Filename, const PCHContainerReader &PCHContainerRdr,
+    StringRef Filename, const PCHContainerReader &PCHContainerRdr,
     WhatToLoad ToLoad, IntrusiveRefCntPtr<DiagnosticsEngine> Diags,
     const FileSystemOptions &FileSystemOpts,
     std::shared_ptr<HeaderSearchOptions> HSOpts,

clang/lib/Frontend/FrontendAction.cpp

@@ -625,8 +625,8 @@ bool FrontendAction::BeginSourceFile(CompilerInstance &CI,
     StringRef InputFile = Input.getFile();
 
     std::unique_ptr<ASTUnit> AST = ASTUnit::LoadFromASTFile(
-        std::string(InputFile), CI.getPCHContainerReader(),
-        ASTUnit::LoadPreprocessorOnly, ASTDiags, CI.getFileSystemOpts(),
+        InputFile, CI.getPCHContainerReader(), ASTUnit::LoadPreprocessorOnly,
+        ASTDiags, CI.getFileSystemOpts(),
         /*HeaderSearchOptions=*/nullptr);
     if (!AST)
       return false;
@@ -693,9 +693,9 @@ bool FrontendAction::BeginSourceFile(CompilerInstance &CI,
     StringRef InputFile = Input.getFile();
 
     std::unique_ptr<ASTUnit> AST = ASTUnit::LoadFromASTFile(
-        std::string(InputFile), CI.getPCHContainerReader(),
-        ASTUnit::LoadEverything, Diags, CI.getFileSystemOpts(),
-        CI.getHeaderSearchOptsPtr(), CI.getLangOptsPtr());
+        InputFile, CI.getPCHContainerReader(), ASTUnit::LoadEverything, Diags,
+        CI.getFileSystemOpts(), CI.getHeaderSearchOptsPtr(),
+        CI.getLangOptsPtr());
 
     if (!AST)
       return false;

clang/tools/c-index-test/core_main.cpp

@@ -274,12 +274,12 @@ static bool printSourceSymbolsFromModule(StringRef modulePath,
 
   IntrusiveRefCntPtr<DiagnosticsEngine> Diags =
       CompilerInstance::createDiagnostics(new DiagnosticOptions());
-  std::unique_ptr<ASTUnit> AU = ASTUnit::LoadFromASTFile(
-      std::string(modulePath), *pchRdr, ASTUnit::LoadASTOnly, Diags,
-      FileSystemOpts, HSOpts, /*LangOpts=*/nullptr,
-      /*OnlyLocalDecls=*/true, CaptureDiagsKind::None,
-      /*AllowASTWithCompilerErrors=*/true,
-      /*UserFilesAreVolatile=*/false);
+  std::unique_ptr<ASTUnit> AU =
+      ASTUnit::LoadFromASTFile(modulePath, *pchRdr, ASTUnit::LoadASTOnly, Diags,
+                               FileSystemOpts, HSOpts, /*LangOpts=*/nullptr,
+                               /*OnlyLocalDecls=*/true, CaptureDiagsKind::None,
+                               /*AllowASTWithCompilerErrors=*/true,
+                               /*UserFilesAreVolatile=*/false);
   if (!AU) {
     errs() << "failed to create TU for: " << modulePath << '\n';
     return true;

clang/tools/clang-extdef-mapping/ClangExtDefMapGen.cpp

@@ -155,7 +155,7 @@ static bool HandleAST(StringRef AstPath) {
   IntrusiveRefCntPtr<DiagnosticsEngine> DiagEngine = GetDiagnosticsEngine();
 
   std::unique_ptr<ASTUnit> Unit = ASTUnit::LoadFromASTFile(
-      AstPath.str(), CI->getPCHContainerOperations()->getRawReader(),
+      AstPath, CI->getPCHContainerOperations()->getRawReader(),
       ASTUnit::LoadASTOnly, DiagEngine, CI->getFileSystemOpts(),
       CI->getHeaderSearchOptsPtr());
 

clang/unittests/Frontend/ASTUnitTest.cpp

@@ -92,8 +92,8 @@ TEST_F(ASTUnitTest, SaveLoadPreservesLangOptionsInPrintingPolicy) {
   auto HSOpts = std::make_shared<HeaderSearchOptions>();
 
   std::unique_ptr<ASTUnit> AU = ASTUnit::LoadFromASTFile(
-      std::string(ASTFileName.str()), PCHContainerOps->getRawReader(),
-      ASTUnit::LoadEverything, Diags, FileSystemOptions(), HSOpts);
+      ASTFileName, PCHContainerOps->getRawReader(), ASTUnit::LoadEverything,
+      Diags, FileSystemOptions(), HSOpts);
 
   if (!AU)
     FAIL() << "failed to load ASTUnit";