[clang] Pass VFS into `ASTUnit::LoadFromASTFile()` (#159166)

This PR makes the `VFS` parameter to `ASTUnit::LoadFromASTFile()`
required and explicit, rather than silently defaulting to the real file
system. This makes it easy to correctly propagate the fully-configured
VFS and load any input files like the rest of the compiler does.

1 files changed, 5 insertions, 4 deletions

diff --git a/clang/lib/Frontend/FrontendAction.cpp b/clang/lib/Frontend/FrontendAction.cpp
index ca37e06..6cc3b65 100644
--- a/clang/lib/Frontend/FrontendAction.cpp
+++ b/clang/lib/Frontend/FrontendAction.cpp
@@ -864,7 +864,8 @@ bool FrontendAction::BeginSourceFile(CompilerInstance &CI,
 
     std::unique_ptr<ASTUnit> AST = ASTUnit::LoadFromASTFile(
         InputFile, CI.getPCHContainerReader(), ASTUnit::LoadPreprocessorOnly,
-        nullptr, ASTDiags, CI.getFileSystemOpts(), CI.getHeaderSearchOpts());
+        CI.getVirtualFileSystemPtr(), nullptr, ASTDiags, CI.getFileSystemOpts(),
+        CI.getHeaderSearchOpts());
     if (!AST)
       return false;
 
@@ -931,9 +932,9 @@ bool FrontendAction::BeginSourceFile(CompilerInstance &CI,
     StringRef InputFile = Input.getFile();
 
     std::unique_ptr<ASTUnit> AST = ASTUnit::LoadFromASTFile(
-        InputFile, CI.getPCHContainerReader(), ASTUnit::LoadEverything, nullptr,
-        Diags, CI.getFileSystemOpts(), CI.getHeaderSearchOpts(),
-        &CI.getLangOpts());
+        InputFile, CI.getPCHContainerReader(), ASTUnit::LoadEverything,
+        CI.getVirtualFileSystemPtr(), nullptr, Diags, CI.getFileSystemOpts(),
+        CI.getHeaderSearchOpts(), &CI.getLangOpts());
 
     if (!AST)
       return false;