1 files changed, 17 insertions, 4 deletions
diff --git a/clang/lib/Frontend/CompilerInstance.cpp b/clang/lib/Frontend/CompilerInstance.cpp
index d314f6d18a6..991e9ef990a 100644
--- a/clang/lib/Frontend/CompilerInstance.cpp
+++ b/clang/lib/Frontend/CompilerInstance.cpp
@@ -1393,8 +1393,21 @@ bool CompilerInstance::loadModuleFile(StringRef FileName) {
         if (Module *M = CI.getPreprocessor()
                             .getHeaderSearchInfo()
                             .getModuleMap()
-                            .findModule(II->getName()))
+                            .findModule(II->getName())) {
           M->HasIncompatibleModuleFile = true;
+
+          // Mark module as available if the only reason it was unavailable
+          // was missing headers.
+          SmallVector<Module *, 2> Stack;
+          Stack.push_back(M);
+          while (!Stack.empty()) {
+            Module *Current = Stack.pop_back_val();
+            if (Current->IsMissingRequirement) continue;
+            Current->IsAvailable = true;
+            Stack.insert(Stack.end(),
+                         Current->submodule_begin(), Current->submodule_end());
+          }
+        }
       }
       LoadedModules.clear();
     }
@@ -1498,7 +1511,7 @@ CompilerInstance::loadModule(SourceLocation ImportLoc,
       if (Module && Module->HasIncompatibleModuleFile) {
         // We tried and failed to load a module file for this module. Fall
         // back to textual inclusion for its headers.
-        return ModuleLoadResult(nullptr, /*missingExpected*/true);
+        return ModuleLoadResult::ConfigMismatch;
       }
 
       getDiagnostics().Report(ModuleNameLoc, diag::err_module_build_disabled)
@@ -1705,7 +1718,7 @@ CompilerInstance::loadModule(SourceLocation ImportLoc,
         << Module->getFullModuleName()
         << SourceRange(Path.front().second, Path.back().second);
 
-      return ModuleLoadResult(nullptr, true);
+      return ModuleLoadResult::MissingExpected;
     }
 
     // Check whether this module is available.
@@ -1739,7 +1752,7 @@ CompilerInstance::loadModule(SourceLocation ImportLoc,
   }
 
   LastModuleImportLoc = ImportLoc;
-  LastModuleImportResult = ModuleLoadResult(Module, false);
+  LastModuleImportResult = ModuleLoadResult(Module);
   return LastModuleImportResult;
 }