Fix a couple of bugs, add some new cool stuff.

1. Fix a todo in Parser::ParseTag, to recover better.  On code like
   that in test/Sema/decl-invalid.c it causes us to return a single
   error instead of multiple.
2. Fix an error in Sema::ParseDeclarator, where it would crash if the
   declarator didn't have an identifier.  Instead, diagnose the problem.
3. Start adding infrastructure to track the range of locations covered
   by a declspec or declarator.  This is mostly implemented for declspec,
   but could be improved, it is missing for declarator.

Thanks to Neil for pointing out this crash.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@40482 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/Driver/TextDiagnosticBuffer.h b/Driver/TextDiagnosticBuffer.h
new file mode 100644
index 0000000..34fbc6e
--- /dev/null
+++ b/Driver/TextDiagnosticBuffer.h
@@ -0,0 +1,51 @@
+//===--- TextDiagnosticBuffer.h - Buffer Text Diagnostics -------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by Bill Wendling and is distributed under the
+// University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This is a concrete diagnostic client, which buffers the diagnostic messages.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef DRIVER_TEXT_DIAGNOSTIC_BUFFER_H_
+#define DRIVER_TEXT_DIAGNOSTIC_BUFFER_H_
+
+#include "TextDiagnostics.h"
+#include <vector>
+
+namespace clang {
+
+class Preprocessor;
+class SourceManager;
+
+class TextDiagnosticBuffer : public TextDiagnostics {
+public:
+  typedef std::vector<std::pair<SourceLocation, std::string> > DiagList;
+  typedef DiagList::iterator iterator;
+  typedef DiagList::const_iterator const_iterator;
+private:
+  DiagList Errors, Warnings;
+public:
+  TextDiagnosticBuffer(SourceManager &SM) : TextDiagnostics(SM) {}
+
+  const_iterator err_begin() const  { return Errors.begin(); }
+  const_iterator err_end() const    { return Errors.end(); }
+
+  const_iterator warn_begin() const { return Warnings.begin(); }
+  const_iterator warn_end() const   { return Warnings.end(); }
+
+  virtual void HandleDiagnostic(Diagnostic::Level DiagLevel,
+                                SourceLocation Pos,
+                                diag::kind ID, const std::string *Strs,
+                                unsigned NumStrs,
+                                const SourceRange *Ranges, 
+                                unsigned NumRanges);
+};
+
+} // end namspace clang
+
+#endif