[Modules] Resolve top-headers of modules lazily.

This allows resolving top-header filenames of modules to FileEntries when
we need them, not eagerly.

Note that that this breaks ABI for libclang functions
clang_Module_getTopLevelHeader / clang_Module_getNumTopLevelHeaders
but this is fine because they are experimental and not widely used yet.

llvm-svn: 176975

1 files changed, 1 insertions, 3 deletions

diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index 93ae6f1c44b..54fe424ddf6 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -3546,9 +3546,7 @@ bool ASTReader::ReadSubmoduleBlock(ModuleFile &F) {
       if (!CurrentModule)
         break;
 
-      // FIXME: Be more lazy about this!
-      if (const FileEntry *File = PP.getFileManager().getFile(Blob))
-        CurrentModule->TopHeaders.insert(File);
+      CurrentModule->addTopHeaderFilename(Blob);
       break;
     }