diff --git a/clang/include/clang/Lex/ModuleMap.h b/clang/include/clang/Lex/ModuleMap.h
--- a/clang/include/clang/Lex/ModuleMap.h
+++ b/clang/include/clang/Lex/ModuleMap.h
@@ -456,8 +456,11 @@
   /// is effectively internal, but is exposed so HeaderSearch can call it.
   void resolveHeaderDirectives(const FileEntry *File) const;
 
-  /// Resolve all lazy header directives for the specified module.
-  void resolveHeaderDirectives(Module *Mod) const;
+  /// Resolve lazy header directives for the specified module. If File is
+  /// provided, only headers with same size and modtime are resolved. If File
+  /// is not set, all headers are resolved.
+  void resolveHeaderDirectives(Module *Mod,
+                               llvm::Optional<const FileEntry *> File) const;
 
   /// Reports errors if a module must not include a specific file.
   ///
diff --git a/clang/lib/Frontend/FrontendAction.cpp b/clang/lib/Frontend/FrontendAction.cpp
--- a/clang/lib/Frontend/FrontendAction.cpp
+++ b/clang/lib/Frontend/FrontendAction.cpp
@@ -331,7 +331,7 @@
     return std::error_code();
 
   // Resolve all lazy header directives to header files.
-  ModMap.resolveHeaderDirectives(Module);
+  ModMap.resolveHeaderDirectives(Module, /*File=*/llvm::None);
 
   // If any headers are missing, we can't build this module. In most cases,
   // diagnostics for this should have already been produced; we only get here
diff --git a/clang/lib/Lex/ModuleMap.cpp b/clang/lib/Lex/ModuleMap.cpp
--- a/clang/lib/Lex/ModuleMap.cpp
+++ b/clang/lib/Lex/ModuleMap.cpp
@@ -482,7 +482,7 @@
 
   if (RequestingModule) {
     resolveUses(RequestingModule, /*Complain=*/false);
-    resolveHeaderDirectives(RequestingModule);
+    resolveHeaderDirectives(RequestingModule, /*File=*/llvm::None);
   }
 
   bool Excluded = false;
@@ -1191,25 +1191,35 @@
   auto BySize = LazyHeadersBySize.find(File->getSize());
   if (BySize != LazyHeadersBySize.end()) {
     for (auto *M : BySize->second)
-      resolveHeaderDirectives(M);
+      resolveHeaderDirectives(M, File);
     LazyHeadersBySize.erase(BySize);
   }
 
   auto ByModTime = LazyHeadersByModTime.find(File->getModificationTime());
   if (ByModTime != LazyHeadersByModTime.end()) {
     for (auto *M : ByModTime->second)
-      resolveHeaderDirectives(M);
+      resolveHeaderDirectives(M, File);
     LazyHeadersByModTime.erase(ByModTime);
   }
 }
 
-void ModuleMap::resolveHeaderDirectives(Module *Mod) const {
+void ModuleMap::resolveHeaderDirectives(
+    Module *Mod, llvm::Optional<const FileEntry *> File) const {
   bool NeedsFramework = false;
-  for (auto &Header : Mod->UnresolvedHeaders)
-    // This operation is logically const; we're just changing how we represent
-    // the header information for this file.
-    const_cast<ModuleMap*>(this)->resolveHeader(Mod, Header, NeedsFramework);
-  Mod->UnresolvedHeaders.clear();
+  SmallVector<Module::UnresolvedHeaderDirective, 1> NewHeaders;
+  const auto Size = File ? File.getValue()->getSize() : 0;
+  const auto ModTime = File ? File.getValue()->getModificationTime() : 0;
+
+  for (auto &Header : Mod->UnresolvedHeaders) {
+    if (File && ((Header.ModTime && Header.ModTime != ModTime) ||
+                 (Header.Size && Header.Size != Size)))
+      NewHeaders.push_back(Header);
+    else
+      // This operation is logically const; we're just changing how we represent
+      // the header information for this file.
+      const_cast<ModuleMap *>(this)->resolveHeader(Mod, Header, NeedsFramework);
+  }
+  Mod->UnresolvedHeaders.swap(NewHeaders);
 }
 
 void ModuleMap::addHeader(Module *Mod, Module::Header Header,
diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -1879,7 +1879,7 @@
       // headers list when emitting resolved headers in the first loop below.
       // FIXME: It'd be preferable to avoid doing this if we were given
       // sufficient stat information in the module map.
-      HS.getModuleMap().resolveHeaderDirectives(M);
+      HS.getModuleMap().resolveHeaderDirectives(M, /*File=*/llvm::None);
 
       // If the file didn't exist, we can still create a module if we were given
       // enough information in the module map.