--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/include/llvm/FuzzMutate/RandomIRBuilder.h	Fri Oct 27 17:07:41 2017 +0900
@@ -0,0 +1,62 @@
+//===-- Mutator.h - Utils for randomly mutation IR --------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Provides the Mutator class, which is used to mutate IR for fuzzing.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_FUZZMUTATE_RANDOMIRBUILDER_H
+#define LLVM_FUZZMUTATE_RANDOMIRBUILDER_H
+
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/FuzzMutate/IRMutator.h"
+#include "llvm/FuzzMutate/Random.h"
+#include <random>
+
+namespace llvm {
+
+using RandomEngine = std::mt19937;
+
+struct RandomIRBuilder {
+  RandomEngine Rand;
+  SmallVector<Type *, 16> KnownTypes;
+
+  RandomIRBuilder(int Seed, ArrayRef<Type *> AllowedTypes)
+      : Rand(Seed), KnownTypes(AllowedTypes.begin(), AllowedTypes.end()) {}
+
+  // TODO: Try to make this a bit less of a random mishmash of functions.
+
+  /// Find a "source" for some operation, which will be used in one of the
+  /// operation's operands. This either selects an instruction in \c Insts or
+  /// returns some new arbitrary Value.
+  Value *findOrCreateSource(BasicBlock &BB, ArrayRef<Instruction *> Insts);
+  /// Find a "source" for some operation, which will be used in one of the
+  /// operation's operands. This either selects an instruction in \c Insts that
+  /// matches \c Pred, or returns some new Value that matches \c Pred. The
+  /// values in \c Srcs should be source operands that have already been
+  /// selected.
+  Value *findOrCreateSource(BasicBlock &BB, ArrayRef<Instruction *> Insts,
+                            ArrayRef<Value *> Srcs, fuzzerop::SourcePred Pred);
+  /// Create some Value suitable as a source for some operation.
+  Value *newSource(BasicBlock &BB, ArrayRef<Instruction *> Insts,
+                   ArrayRef<Value *> Srcs, fuzzerop::SourcePred Pred);
+  /// Find a viable user for \c V in \c Insts, which should all be contained in
+  /// \c BB. This may also create some new instruction in \c BB and use that.
+  void connectToSink(BasicBlock &BB, ArrayRef<Instruction *> Insts, Value *V);
+  /// Create a user for \c V in \c BB.
+  void newSink(BasicBlock &BB, ArrayRef<Instruction *> Insts, Value *V);
+  Value *findPointer(BasicBlock &BB, ArrayRef<Instruction *> Insts,
+                     ArrayRef<Value *> Srcs, fuzzerop::SourcePred Pred);
+  Type *chooseType(LLVMContext &Context, ArrayRef<Value *> Srcs,
+                   fuzzerop::SourcePred Pred);
+};
+
+} // end llvm namespace
+
+#endif // LLVM_FUZZMUTATE_RANDOMIRBUILDER_H