Template diffing: Type eliding and tree printing

include/clang/Basic/Diagnostic.h

Index: include/clang/Basic/Diagnostic.h
===================================================================
--- include/clang/Basic/Diagnostic.h	(revision 145976)
+++ include/clang/Basic/Diagnostic.h	(working copy)
@@ -132,7 +132,8 @@
     ak_declarationname, // DeclarationName
     ak_nameddecl,       // NamedDecl *
     ak_nestednamespec,  // NestedNameSpecifier *
-    ak_declcontext      // DeclContext *
+    ak_declcontext,     // DeclContext *
+    ak_qualtype_pair    // pair<QualType, QualType>
   };
 
   /// Specifies which overload candidates to display when overload resolution
@@ -154,6 +155,9 @@
   bool ErrorsAsFatal;            // Treat errors like fatal errors.
   bool SuppressSystemWarnings;   // Suppress warnings in system headers.
   bool SuppressAllDiagnostics;   // Suppress all diagnostics.
+  bool ElideType;                // Elide common types of templates.
+  bool PrintTemplateTree;        // Print a tree when comparing templates.
+  bool ShowColors;               // Color printing is enabled.
   OverloadsShown ShowOverloads;  // Which overload candidates to show.
   unsigned ErrorLimit;           // Cap of # errors emitted, 0 -> no limit.
   unsigned TemplateBacktraceLimit; // Cap on depth of template backtrace stack,
@@ -403,7 +407,22 @@
     SuppressAllDiagnostics = Val; 
   }
   bool getSuppressAllDiagnostics() const { return SuppressAllDiagnostics; }
-  
+ 
+  /// \brief Set type eliding, to skip outputing same types occuring in
+  /// template types.
+  void setElideType(bool Val = true) { ElideType = Val; }
+  bool getElideType() { return ElideType; }
+ 
+  /// \brief Set type eliding, to skip outputing same types occuring in
+  /// template types.
+  void setPrintTemplateTree(bool Val = false) { PrintTemplateTree = Val; }
+  bool getPrintTemplateTree() { return PrintTemplateTree; }
+ 
+  /// \brief Set type eliding, to skip outputing same types occuring in
+  /// template types.
+  void setShowColors(bool Val = false) { ShowColors = Val; }
+  bool getShowColors() { return ShowColors; }
+ 
   /// \brief Specify which overload candidates to show when overload resolution
   /// fails.  By default, we show all candidates.
   void setShowOverloads(OverloadsShown Val) {
@@ -614,6 +633,9 @@
   /// sort of argument kind it is.
   intptr_t DiagArgumentsVal[MaxArguments];
 
+  /// \brief Stores a pair of types for type diffing.
+  intptr_t FromType, ToType;
+
   /// DiagRanges - The list of ranges added to this diagnostic.  It currently
   /// only support 10 ranges, could easily be extended if needed.
   CharSourceRange DiagRanges[10];
@@ -705,7 +727,11 @@
   void operator=(const DiagnosticBuilder&); // DO NOT IMPLEMENT
   friend class DiagnosticsEngine;
   explicit DiagnosticBuilder(DiagnosticsEngine *diagObj)
-    : DiagObj(diagObj), NumArgs(0), NumRanges(0), NumFixItHints(0) {}
+    : DiagObj(diagObj), NumArgs(0), NumRanges(0), NumFixItHints(0) {
+    // FromType and ToType aren't cleared from the last use, so blank them here.
+    diagObj->FromType = 0;
+    diagObj->ToType = 0;
+  }
 
   friend class PartialDiagnostic;
 
@@ -803,6 +829,14 @@
     if (DiagObj)
       DiagObj->FixItHints[NumFixItHints++] = Hint;
   }
+
+  void AddTypePair(intptr_t FromType, intptr_t ToType) const {
+    assert(DiagObj->FromType == 0 && DiagObj->ToType == 0 && 
+           "Only one type diff allowed per diagnostic");
+    DiagObj->FromType = FromType;
+    DiagObj->ToType = ToType;
+    DiagObj->DiagArgumentsKind[NumArgs++] = DiagnosticsEngine::ak_qualtype_pair;
+  }
 };
 
 inline const DiagnosticBuilder &operator<<(const DiagnosticBuilder &DB,
@@ -959,7 +993,14 @@
     return DiagObj->DiagArgumentsVal[Idx];
   }
 
+  intptr_t getFromDiffType() const {
+    return DiagObj->FromType;
+  }
 
+  intptr_t getToDiffType() const {
+    return DiagObj->ToType;
+  }
+
   /// getNumRanges - Return the number of source ranges associated with this
   /// diagnostic.
   unsigned getNumRanges() const {
@@ -1109,6 +1150,19 @@
   }
 };
 
+enum TemplateDiffFlags {
+  TD_PrintTree = 1,
+  TD_PrintFromType = 2,
+  TD_ElideType = 4,
+  TD_ShowColors = 8
+};
+
+enum {
+  /// Special character that the diagnostic printer will use to toggle the bold
+  /// attribute.  The character itself will be not be printed.
+  ToggleBold = 127
+};
+
 }  // end namespace clang
 
 #endif