diff --git a/tools/llvm-diff/DifferenceEngine.h b/tools/llvm-diff/DifferenceEngine.h
index 6eefb06..5b4f80b 100644
--- a/tools/llvm-diff/DifferenceEngine.h
+++ b/tools/llvm-diff/DifferenceEngine.h
@@ -17,6 +17,8 @@
 
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
+#include "DiffLog.h"
+#include "DiffConsumer.h"
 
 #include <utility>
 
@@ -32,95 +34,6 @@
   /// A class for performing structural comparisons of LLVM assembly.
   class DifferenceEngine {
   public:
-    /// A temporary-object class for building up log messages.
-    class LogBuilder {
-      DifferenceEngine &Engine;
-
-      /// The use of a stored StringRef here is okay because
-      /// LogBuilder should be used only as a temporary, and as a
-      /// temporary it will be destructed before whatever temporary
-      /// might be initializing this format.
-      StringRef Format;
-
-      SmallVector<Value*, 4> Arguments;
-
-    public:
-      LogBuilder(DifferenceEngine &Engine, StringRef Format)
-        : Engine(Engine), Format(Format) {}
-
-      LogBuilder &operator<<(Value *V) {
-        Arguments.push_back(V);
-        return *this;
-      }
-
-      ~LogBuilder() {
-        Engine.consumer.logf(*this);
-      }
-
-      StringRef getFormat() const { return Format; }
-
-      unsigned getNumArguments() const { return Arguments.size(); }
-      Value *getArgument(unsigned I) const { return Arguments[I]; }
-    };
-
-    enum DiffChange { DC_match, DC_left, DC_right };
-
-    /// A temporary-object class for building up diff messages.
-    class DiffLogBuilder {
-      typedef std::pair<Instruction*,Instruction*> DiffRecord;
-      SmallVector<DiffRecord, 20> Diff;
-
-      DifferenceEngine &Engine;
-
-    public:
-      DiffLogBuilder(DifferenceEngine &Engine) : Engine(Engine) {}
-      ~DiffLogBuilder() { Engine.consumer.logd(*this); }
-
-      void addMatch(Instruction *L, Instruction *R) {
-        Diff.push_back(DiffRecord(L, R));
-      }
-      void addLeft(Instruction *L) {
-        // HACK: VS 2010 has a bug in the stdlib that requires this.
-        Diff.push_back(DiffRecord(L, DiffRecord::second_type(0)));
-      }
-      void addRight(Instruction *R) {
-        // HACK: VS 2010 has a bug in the stdlib that requires this.
-        Diff.push_back(DiffRecord(DiffRecord::first_type(0), R));
-      }
-
-      unsigned getNumLines() const { return Diff.size(); }
-      DiffChange getLineKind(unsigned I) const {
-        return (Diff[I].first ? (Diff[I].second ? DC_match : DC_left)
-                              : DC_right);
-      }
-      Instruction *getLeft(unsigned I) const { return Diff[I].first; }
-      Instruction *getRight(unsigned I) const { return Diff[I].second; }
-    };
-
-    /// The interface for consumers of difference data.
-    struct Consumer {
-      /// Record that a local context has been entered.  Left and
-      /// Right are IR "containers" of some sort which are being
-      /// considered for structural equivalence: global variables,
-      /// functions, blocks, instructions, etc.
-      virtual void enterContext(Value *Left, Value *Right) = 0;
-
-      /// Record that a local context has been exited.
-      virtual void exitContext() = 0;
-
-      /// Record a difference within the current context.
-      virtual void log(StringRef Text) = 0;
-
-      /// Record a formatted difference within the current context.
-      virtual void logf(const LogBuilder &Log) = 0;
-
-      /// Record a line-by-line instruction diff.
-      virtual void logd(const DiffLogBuilder &Log) = 0;
-
-    protected:
-      virtual ~Consumer() {}
-    };
-
     /// A RAII object for recording the current context.
     struct Context {
       Context(DifferenceEngine &Engine, Value *L, Value *R) : Engine(Engine) {
@@ -149,14 +62,13 @@
 
     void diff(Module *L, Module *R);
     void diff(Function *L, Function *R);
-
     void log(StringRef text) {
       consumer.log(text);
     }
-
     LogBuilder logf(StringRef text) {
-      return LogBuilder(*this, text);
+      return LogBuilder(consumer, text);
     }
+    Consumer& getConsumer() const { return consumer; }
 
     /// Installs an oracle to decide whether two global values are
     /// equivalent as operands.  Without an oracle, global values are