When preprocessing with -frewrite-imports and -fmodule-file=, do not pass all

modules to preprocessing of nested .pcm files.

Making those module files available results in loading more .pcm files than
necessary, and potentially in misbehavior if a module makes itself visible
during its own compilation (as parts of that module that have not yet been
processed would then become visible).

llvm-svn: 306320

1 files changed, 2 insertions, 0 deletions

diff --git a/clang/lib/Frontend/Rewrite/FrontendActions.cpp b/clang/lib/Frontend/Rewrite/FrontendActions.cpp
index f64fbdafd59..e93f737c47f 100644
--- a/clang/lib/Frontend/Rewrite/FrontendActions.cpp
+++ b/clang/lib/Frontend/Rewrite/FrontendActions.cpp
@@ -247,6 +247,8 @@ public:
     Instance.getFrontendOpts().Inputs.clear();
     Instance.getFrontendOpts().Inputs.emplace_back(
         Filename, InputKind(InputKind::Unknown, InputKind::Precompiled));
+    Instance.getFrontendOpts().ModuleFiles.clear();
+    Instance.getFrontendOpts().ModuleMapFiles.clear();
     // Don't recursively rewrite imports. We handle them all at the top level.
     Instance.getPreprocessorOutputOpts().RewriteImports = false;