1 files changed, 21 insertions, 5 deletions
diff --git a/clang/lib/Serialization/ModuleManager.cpp b/clang/lib/Serialization/ModuleManager.cpp
index 5613d372d20..ca910befcd2 100644
--- a/clang/lib/Serialization/ModuleManager.cpp
+++ b/clang/lib/Serialization/ModuleManager.cpp
@@ -135,19 +135,31 @@ ModuleManager::addModule(StringRef FileName, ModuleKind Type,
   return NewModule? NewlyLoaded : AlreadyLoaded;
 }
 
+static void getModuleFileAncestors(
+    ModuleFile *F,
+    llvm::SmallPtrSetImpl<ModuleFile *> &Ancestors) {
+  Ancestors.insert(F);
+  for (ModuleFile *Importer : F->ImportedBy)
+    getModuleFileAncestors(Importer, Ancestors);
+}
+
 void ModuleManager::removeModules(ModuleIterator first, ModuleIterator last,
                                   ModuleMap *modMap) {
   if (first == last)
     return;
 
-  // The first file entry is about to be rebuilt (or there was an error), so
-  // there should be no references to it. Remove it from the cache to close it,
-  // as Windows doesn't seem to allow renaming over an open file.
-  FileMgr.invalidateCache((*first)->File);
-
   // Collect the set of module file pointers that we'll be removing.
   llvm::SmallPtrSet<ModuleFile *, 4> victimSet(first, last);
 
+  // The last module file caused the load failure, so it and its ancestors in
+  // the module dependency tree will be rebuilt (or there was an error), so
+  // there should be no references to them. Collect the files to remove from
+  // the cache below, since rebuilding them will create new files at the old
+  // locations.
+  llvm::SmallPtrSet<ModuleFile *, 4> Ancestors;
+  getModuleFileAncestors(*(last-1), Ancestors);
+  assert(Ancestors.count(*first) && "non-dependent module loaded");
+
   // Remove any references to the now-destroyed modules.
   for (unsigned i = 0, n = Chain.size(); i != n; ++i) {
     Chain[i]->ImportedBy.remove_if([&](ModuleFile *MF) {
@@ -165,6 +177,10 @@ void ModuleManager::removeModules(ModuleIterator first, ModuleIterator last,
         mod->setASTFile(nullptr);
       }
     }
+
+    if (Ancestors.count(*victim))
+      FileMgr.invalidateCache((*victim)->File);
+
     delete *victim;
   }