2 files changed, 46 insertions, 8 deletions

diff --git a/clang/tools/CIndex/CIndex.cpp b/clang/tools/CIndex/CIndex.cpp
index 8bb6a0a7c5f..128b3b6e992 100644
--- a/clang/tools/CIndex/CIndex.cpp
+++ b/clang/tools/CIndex/CIndex.cpp
@@ -903,10 +903,13 @@ bool CursorVisitor::VisitAttributes(Decl *D) {
 }
 
 extern "C" {
-CXIndex clang_createIndex(int excludeDeclarationsFromPCH) {
+CXIndex clang_createIndex(int excludeDeclarationsFromPCH,
+                          int displayDiagnostics) {
   CIndexer *CIdxr = new CIndexer();
   if (excludeDeclarationsFromPCH)
     CIdxr->setOnlyLocalDecls();
+  if (displayDiagnostics)
+    CIdxr->setDisplayDiagnostics();
   return CIdxr;
 }
 
@@ -993,8 +996,18 @@ clang_createTranslationUnitFromSourceFile(CXIndex CIdx,
 
     // FIXME: Until we have broader testing, just drop the entire AST if we
     // encountered an error.
-    if (NumErrors != Diags->getNumErrors())
+    if (NumErrors != Diags->getNumErrors()) {
+      if (CXXIdx->getDisplayDiagnostics()) {
+        for (ASTUnit::diag_iterator D = Unit->diag_begin(), 
+                                 DEnd = Unit->diag_end();
+             D != DEnd; ++D) {
+          CXStoredDiagnostic Diag(*D, Unit->getASTContext().getLangOptions());
+          clang_displayDiagnostic(&Diag, stderr,
+                                  clang_defaultDiagnosticDisplayOptions());
+        }
+      }
       return 0;
+    }
 
     return Unit.take();
   }
@@ -1085,18 +1098,35 @@ clang_createTranslationUnitFromSourceFile(CXIndex CIdx,
                                           RemappedFiles.data(),
                                           RemappedFiles.size(),
                                           /*CaptureDiagnostics=*/true);
-  if (ATU)
-    ATU->unlinkTemporaryFile();
-
-  // FIXME: Currently we don't report diagnostics on invalid ASTs.
   if (ATU) {
     LoadSerializedDiagnostics(DiagnosticsFile, 
                               num_unsaved_files, unsaved_files,
                               ATU->getFileManager(),
                               ATU->getSourceManager(),
                               ATU->getDiagnostics());
+  } else if (CXXIdx->getDisplayDiagnostics()) {
+    // We failed to load the ASTUnit, but we can still deserialize the
+    // diagnostics and emit them.
+    FileManager FileMgr;
+    SourceManager SourceMgr;
+    // FIXME: Faked LangOpts!
+    LangOptions LangOpts;
+    llvm::SmallVector<StoredDiagnostic, 4> Diags;
+    LoadSerializedDiagnostics(DiagnosticsFile, 
+                              num_unsaved_files, unsaved_files,
+                              FileMgr, SourceMgr, Diags);
+    for (llvm::SmallVector<StoredDiagnostic, 4>::iterator D = Diags.begin(), 
+                                                       DEnd = Diags.end();
+         D != DEnd; ++D) {
+      CXStoredDiagnostic Diag(*D, LangOpts);
+      clang_displayDiagnostic(&Diag, stderr,
+                              clang_defaultDiagnosticDisplayOptions());
+    }
   }
 
+  if (ATU)
+    ATU->unlinkTemporaryFile();
+
   for (unsigned i = 0, e = TemporaryFiles.size(); i != e; ++i)
     TemporaryFiles[i].eraseFromDisk();
 
diff --git a/clang/tools/CIndex/CIndexer.h b/clang/tools/CIndex/CIndexer.h
index d559f138647..1fa3ca93876 100644
--- a/clang/tools/CIndex/CIndexer.h
+++ b/clang/tools/CIndex/CIndexer.h
@@ -34,11 +34,14 @@ namespace cxstring {
 class CIndexer {
   bool UseExternalASTGeneration;
   bool OnlyLocalDecls;
-  
+  bool DisplayDiagnostics;
+
   llvm::sys::Path ClangPath;
   
 public:
-  CIndexer() : UseExternalASTGeneration(false), OnlyLocalDecls(false) { }
+ CIndexer() 
+   : UseExternalASTGeneration(false), OnlyLocalDecls(false),
+     DisplayDiagnostics(false) { }
   
   /// \brief Whether we only want to see "local" declarations (that did not
   /// come from a previous precompiled header). If false, we want to see all
@@ -46,6 +49,11 @@ public:
   bool getOnlyLocalDecls() const { return OnlyLocalDecls; }
   void setOnlyLocalDecls(bool Local = true) { OnlyLocalDecls = Local; }
   
+  bool getDisplayDiagnostics() const { return DisplayDiagnostics; }
+  void setDisplayDiagnostics(bool Display = true) {
+    DisplayDiagnostics = Display;
+  }
+
   bool getUseExternalASTGeneration() const { return UseExternalASTGeneration; }
   void setUseExternalASTGeneration(bool Value) {
     UseExternalASTGeneration = Value;