Detect when mapping a #include/#import over to a submodule ends up

hitting a submodule that was never actually created, e.g., because
that header wasn't parsed. In such cases, complain (because the
module's umbrella headers don't cover everything) and fall back to
including the header.

Later, we'll add a warning at module-build time to catch all such
cases. However, this fallback is important to eliminate assertions in
the ASTWriter when this happens.

llvm-svn: 146933

4 files changed, 21 insertions, 6 deletions

diff --git a/clang/lib/Frontend/CompilerInstance.cpp b/clang/lib/Frontend/CompilerInstance.cpp
index 66238d0fc9f..12d368501ce 100644
--- a/clang/lib/Frontend/CompilerInstance.cpp
+++ b/clang/lib/Frontend/CompilerInstance.cpp
@@ -1270,9 +1270,23 @@ Module *CompilerInstance::loadModule(SourceLocation ImportLoc,
   
   // Make the named module visible, if it's not already part of the module
   // we are parsing.
-  if (ModuleName != getLangOpts().CurrentModule)
+  if (ModuleName != getLangOpts().CurrentModule) {
+    if (!Module->IsFromModuleFile) {
+      // We have an umbrella header or directory that doesn't actually include
+      // all of the headers within the directory it covers. Complain about
+      // this missing submodule and recover by forgetting that we ever saw
+      // this submodule.
+      // FIXME: Should we detect this at module load time? It seems fairly
+      // expensive (and rare).
+      getDiagnostics().Report(ImportLoc, diag::warn_missing_submodule)
+        << Module->getFullModuleName()
+        << SourceRange(Path.front().second, Path.back().second);
+      
+      return 0;
+    }
     ModuleManager->makeModuleVisible(Module, Visibility);
-
+  }
+  
   // If this module import was due to an inclusion directive, create an 
   // implicit import declaration to capture it in the AST.
   if (IsInclusionDirective && hasASTContext()) {
diff --git a/clang/lib/Lex/PPDirectives.cpp b/clang/lib/Lex/PPDirectives.cpp
index 7c8bfd7e7cd..4d700aef03b 100644
--- a/clang/lib/Lex/PPDirectives.cpp
+++ b/clang/lib/Lex/PPDirectives.cpp
@@ -1388,11 +1388,12 @@ void Preprocessor::HandleIncludeDirective(SourceLocation HashLoc,
     // If this was an #__include_macros directive, only make macros visible.
     Module::NameVisibilityKind Visibility 
       = (IncludeKind == 3)? Module::MacrosVisible : Module::AllVisible;
-    TheModuleLoader.loadModule(IncludeTok.getLocation(), Path, Visibility,
-                               /*IsIncludeDirective=*/true);
+    Module *Imported
+      = TheModuleLoader.loadModule(IncludeTok.getLocation(), Path, Visibility,
+                                   /*IsIncludeDirective=*/true);
     
     // If this header isn't part of the module we're building, we're done.
-    if (!BuildingImportedModule)
+    if (!BuildingImportedModule && Imported)
       return;
   }
   
diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index 1efc95408b3..9fc2962d27c 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -3086,6 +3086,7 @@ ASTReader::ASTReadResult ASTReader::ReadSubmoduleBlock(ModuleFile &F) {
         return Failure;
       }
       
+      CurrentModule->IsFromModuleFile = true;
       CurrentModule->InferSubmodules = InferSubmodules;
       CurrentModule->InferExplicitSubmodules = InferExplicitSubmodules;
       CurrentModule->InferExportWildcard = InferExportWildcard;
diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
index 1776b97bb03..6883dbe3294 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -1877,7 +1877,6 @@ void ASTWriter::WriteSubmodules(Module *WritingModule) {
   for (ASTContext::import_iterator I = Context->local_import_begin(),
                                 IEnd = Context->local_import_end();
        I != IEnd; ++I) {
-    assert(SubmoduleIDs.find(I->getImportedModule()) != SubmoduleIDs.end());
     if (Module *ImportedFrom
           = ModMap.inferModuleFromLocation(FullSourceLoc(I->getLocation(), 
                                                          SrcMgr))) {