diff --git a/tools/CIndex/CIndex.cpp b/tools/CIndex/CIndex.cpp
index 57b463c..ee73946 100644
--- a/tools/CIndex/CIndex.cpp
+++ b/tools/CIndex/CIndex.cpp
@@ -1044,6 +1044,13 @@
       argv.push_back(arg);
     }
 
+  // Generate a temporary name for the diagnostics file.
+  char tmpFileResults[L_tmpnam];
+  char *tmpResultsFileName = tmpnam(tmpFileResults);
+  llvm::sys::Path DiagnosticsFile(tmpResultsFileName);
+  TemporaryFiles.push_back(DiagnosticsFile);
+  argv.push_back("-fdiagnostics-binary");
+
   // Add the null terminator.
   argv.push_back(NULL);
 
@@ -1051,7 +1058,8 @@
   llvm::sys::Path DevNull; // leave empty, causes redirection to /dev/null
                            // on Unix or NUL (Windows).
   std::string ErrMsg;
-  const llvm::sys::Path *Redirects[] = { &DevNull, &DevNull, &DevNull, NULL };
+  const llvm::sys::Path *Redirects[] = { &DevNull, &DevNull, &DiagnosticsFile,
+                                         NULL };
   llvm::sys::Program::ExecuteAndWait(ClangPath, &argv[0], /* env */ NULL,
       /* redirects */ &Redirects[0],
       /* secondsToWait */ 0, /* memoryLimits */ 0, &ErrMsg);
@@ -1078,6 +1086,9 @@
   if (ATU)
     ATU->unlinkTemporaryFile();
   
+  ReportSerializedDiagnostics(DiagnosticsFile, *Diags, 
+                              num_unsaved_files, unsaved_files);
+
   for (unsigned i = 0, e = TemporaryFiles.size(); i != e; ++i)
     TemporaryFiles[i].eraseFromDisk();
   
diff --git a/tools/CIndex/CIndexCodeCompletion.cpp b/tools/CIndex/CIndexCodeCompletion.cpp
index 25b1417..fe4eb8a 100644
--- a/tools/CIndex/CIndexCodeCompletion.cpp
+++ b/tools/CIndex/CIndexCodeCompletion.cpp
@@ -231,7 +231,8 @@
   argv.push_back("-no-code-completion-debug-printer");
   argv.push_back("-Xclang");
   argv.push_back("-code-completion-macros");
-  
+  argv.push_back("-fdiagnostics-binary");
+
   // Remap any unsaved files to temporary files.
   std::vector<std::string> RemapArgs;
   if (RemapFiles(num_unsaved_files, unsaved_files, RemapArgs, TemporaryFiles))
@@ -267,17 +268,24 @@
   // Add the null terminator.
   argv.push_back(NULL);
 
-  // Generate a temporary name for the AST file.
+  // Generate a temporary name for the code-completion results file.
   char tmpFile[L_tmpnam];
   char *tmpFileName = tmpnam(tmpFile);
   llvm::sys::Path ResultsFile(tmpFileName);
   TemporaryFiles.push_back(ResultsFile);
 
+  // Generate a temporary name for the diagnostics file.
+  char tmpFileResults[L_tmpnam];
+  char *tmpResultsFileName = tmpnam(tmpFileResults);
+  llvm::sys::Path DiagnosticsFile(tmpResultsFileName);
+  TemporaryFiles.push_back(DiagnosticsFile);
+
   // Invoke 'clang'.
   llvm::sys::Path DevNull; // leave empty, causes redirection to /dev/null
                            // on Unix or NUL (Windows).
   std::string ErrMsg;
-  const llvm::sys::Path *Redirects[] = { &DevNull, &ResultsFile, &DevNull, 0 };
+  const llvm::sys::Path *Redirects[] = { &DevNull, &ResultsFile, 
+                                         &DiagnosticsFile, 0 };
   llvm::sys::Program::ExecuteAndWait(ClangPath, &argv[0], /* env */ NULL,
                                      /* redirects */ &Redirects[0],
                                      /* secondsToWait */ 0,
@@ -331,7 +339,8 @@
     Results->Buffer = F;
   }
 
-  // FIXME: Parse the (redirected) standard error to emit diagnostics.
+  ReportSerializedDiagnostics(DiagnosticsFile, *Diags, 
+                              num_unsaved_files, unsaved_files);
   
   for (unsigned i = 0, e = TemporaryFiles.size(); i != e; ++i)
     TemporaryFiles[i].eraseFromDisk();
diff --git a/tools/CIndex/CIndexDiagnostic.cpp b/tools/CIndex/CIndexDiagnostic.cpp
index 9a21f38..eb039df 100644
--- a/tools/CIndex/CIndexDiagnostic.cpp
+++ b/tools/CIndex/CIndexDiagnostic.cpp
@@ -14,6 +14,9 @@
 #include "CIndexer.h"
 #include "CXSourceLocation.h"
 
+#include "clang/Frontend/FrontendDiagnostic.h"
+#include "llvm/Support/MemoryBuffer.h"
+
 using namespace clang;
 using namespace clang::cxloc;
 
@@ -196,3 +199,47 @@
 }
   
 } // end extern "C"
+
+void clang::ReportSerializedDiagnostics(const llvm::sys::Path &DiagnosticsPath,
+                                        Diagnostic &Diags,
+                                        unsigned num_unsaved_files,
+                                        struct CXUnsavedFile *unsaved_files) {
+  using llvm::MemoryBuffer;
+  using llvm::StringRef;
+  MemoryBuffer *F = MemoryBuffer::getFile(DiagnosticsPath.c_str());
+  if (!F)
+    return;
+
+  // Enter the unsaved files into the file manager.
+  SourceManager SourceMgr;
+  FileManager FileMgr;
+  for (unsigned I = 0; I != num_unsaved_files; ++I) {
+    const FileEntry *File = FileMgr.getVirtualFile(unsaved_files[I].Filename,
+                                                   unsaved_files[I].Length,
+                                                   0);
+    if (!File) {
+      Diags.Report(diag::err_fe_remap_missing_from_file)
+        << unsaved_files[I].Filename;
+      return;
+    }
+
+    MemoryBuffer *Buffer
+      = MemoryBuffer::getMemBuffer(unsaved_files[I].Contents,
+                           unsaved_files[I].Contents + unsaved_files[I].Length);
+    if (!Buffer)
+      return;
+
+    SourceMgr.overrideFileContents(File, Buffer);
+  }
+
+  // Parse the diagnostics, emitting them one by one until we've
+  // exhausted the data.
+  StringRef Buffer = F->getBuffer();
+  const char *Memory = Buffer.data(), *MemoryEnd = Memory + Buffer.size();
+  while (Memory != MemoryEnd) {
+    DiagnosticBuilder DB = Diags.Deserialize(FileMgr, SourceMgr, 
+                                             Memory, MemoryEnd);
+    if (!DB.isActive())
+      return;
+  }
+}
diff --git a/tools/CIndex/CIndexDiagnostic.h b/tools/CIndex/CIndexDiagnostic.h
index f962041..62d219c 100644
--- a/tools/CIndex/CIndexDiagnostic.h
+++ b/tools/CIndex/CIndexDiagnostic.h
@@ -1,4 +1,4 @@
-/*===-- CIndexDiagnostic.h - Diagnostics C Interface --------------*- C -*-===*\
+/*===-- CIndexDiagnostic.h - Diagnostics C Interface ------------*- C++ -*-===*\
 |*                                                                            *|
 |*                     The LLVM Compiler Infrastructure                       *|
 |*                                                                            *|
@@ -17,8 +17,13 @@
 #include "clang/Basic/Diagnostic.h"
 #include "clang/Basic/LangOptions.h"
 
+namespace llvm { namespace sys {
+class Path;
+} }
+
 namespace clang {
 
+class Diagnostic;
 class Preprocessor;
   
 /**
@@ -43,7 +48,15 @@
   virtual void HandleDiagnostic(Diagnostic::Level DiagLevel,
                                 const DiagnosticInfo &Info);
 };
-  
+
+/// \brief Given the path to a file that contains binary, serialized
+/// diagnostics produced by Clang, emit those diagnostics via the
+/// given diagnostic engine.
+void ReportSerializedDiagnostics(const llvm::sys::Path &DiagnosticsPath,
+                                 Diagnostic &Diags,
+                                 unsigned num_unsaved_files,
+                                 struct CXUnsavedFile *unsaved_files);
+
 } // end namespace clang
 
 #endif // LLVM_CLANG_CINDEX_DIAGNOSTIC_H