From d213aab71d07b797948dcf9b0cf69b258047c5fe Mon Sep 17 00:00:00 2001
From: Ben Langmuir <blangmuir@apple.com>
Date: Fri, 26 Sep 2014 22:42:23 +0000
Subject: [PATCH] Ensure that all module build failures get diagnosed

Otherwise we can end up silently skipping an import.  If we happen to be
building another module at the time, we may build a mysteriously broken
module and not know why it seems to be missing symbols.

llvm-svn: 218552
---
 clang/include/clang/Basic/DiagnosticCommonKinds.td |  2 ++
 clang/lib/Frontend/CompilerInstance.cpp            | 13 +++++++++++--
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/clang/include/clang/Basic/DiagnosticCommonKinds.td b/clang/include/clang/Basic/DiagnosticCommonKinds.td
index 0b7f9875e5bf..ff9ed69022ec 100644
--- a/clang/include/clang/Basic/DiagnosticCommonKinds.td
+++ b/clang/include/clang/Basic/DiagnosticCommonKinds.td
@@ -81,6 +81,8 @@ def err_deleted_non_function : Error<
   "only functions can have deleted definitions">;
 def err_module_not_found : Error<"module '%0' not found">, DefaultFatal;
 def err_module_not_built : Error<"could not build module '%0'">, DefaultFatal;
+def err_module_lock_failure : Error<
+  "could not acquire lock file for module '%0'">, DefaultFatal;
 def err_module_cycle : Error<"cyclic dependency in module '%0': %1">, 
   DefaultFatal;
 def note_pragma_entered_here : Note<"#pragma entered here">;  
diff --git a/clang/lib/Frontend/CompilerInstance.cpp b/clang/lib/Frontend/CompilerInstance.cpp
index 9f69e9c47f0a..923881c2efe3 100644
--- a/clang/lib/Frontend/CompilerInstance.cpp
+++ b/clang/lib/Frontend/CompilerInstance.cpp
@@ -990,9 +990,10 @@ static bool compileAndLoadModule(CompilerInstance &ImportingInstance,
                                  SourceLocation ImportLoc,
                                  SourceLocation ModuleNameLoc, Module *Module,
                                  StringRef ModuleFileName) {
+  DiagnosticsEngine &Diags = ImportingInstance.getDiagnostics();
+
   auto diagnoseBuildFailure = [&] {
-    ImportingInstance.getDiagnostics().Report(ModuleNameLoc,
-                                              diag::err_module_not_built)
+    Diags.Report(ModuleNameLoc, diag::err_module_not_built)
         << Module->Name << SourceRange(ImportLoc, ModuleNameLoc);
   };
 
@@ -1006,6 +1007,8 @@ static bool compileAndLoadModule(CompilerInstance &ImportingInstance,
     llvm::LockFileManager Locked(ModuleFileName);
     switch (Locked) {
     case llvm::LockFileManager::LFS_Error:
+      Diags.Report(ModuleNameLoc, diag::err_module_lock_failure)
+          << Module->Name;
       return false;
 
     case llvm::LockFileManager::LFS_Owned:
@@ -1040,6 +1043,10 @@ static bool compileAndLoadModule(CompilerInstance &ImportingInstance,
       continue;
     } else if (ReadResult == ASTReader::Missing) {
       diagnoseBuildFailure();
+    } else if (ReadResult != ASTReader::Success &&
+               !Diags.hasErrorOccurred()) {
+      // The ASTReader didn't diagnose the error, so conservatively report it.
+      diagnoseBuildFailure();
     }
     return ReadResult == ASTReader::Success;
   }
@@ -1362,6 +1369,8 @@ CompilerInstance::loadModule(SourceLocation ImportLoc,
       // Try to compile and then load the module.
       if (!compileAndLoadModule(*this, ImportLoc, ModuleNameLoc, Module,
                                 ModuleFileName)) {
+        assert(getDiagnostics().hasErrorOccurred() &&
+               "undiagnosed error in compileAndLoadModule");
         if (getPreprocessorOpts().FailedModules)
           getPreprocessorOpts().FailedModules->addFailed(ModuleName);
         KnownModules[Path[0].first] = nullptr;