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       1             : //===-- Mutator.h - Utils for randomly mutation IR --------------*- C++ -*-===//
       2             : //
       3             : //                     The LLVM Compiler Infrastructure
       4             : //
       5             : // This file is distributed under the University of Illinois Open Source
       6             : // License. See LICENSE.TXT for details.
       7             : //
       8             : //===----------------------------------------------------------------------===//
       9             : //
      10             : // Provides the Mutator class, which is used to mutate IR for fuzzing.
      11             : //
      12             : //===----------------------------------------------------------------------===//
      13             : 
      14             : #ifndef LLVM_FUZZMUTATE_RANDOMIRBUILDER_H
      15             : #define LLVM_FUZZMUTATE_RANDOMIRBUILDER_H
      16             : 
      17             : #include "llvm/ADT/SmallPtrSet.h"
      18             : #include "llvm/FuzzMutate/IRMutator.h"
      19             : #include "llvm/FuzzMutate/Random.h"
      20             : #include <random>
      21             : 
      22             : namespace llvm {
      23             : 
      24             : using RandomEngine = std::mt19937;
      25             : 
      26          28 : struct RandomIRBuilder {
      27             :   RandomEngine Rand;
      28             :   SmallVector<Type *, 16> KnownTypes;
      29             : 
      30          28 :   RandomIRBuilder(int Seed, ArrayRef<Type *> AllowedTypes)
      31          56 :       : Rand(Seed), KnownTypes(AllowedTypes.begin(), AllowedTypes.end()) {}
      32             : 
      33             :   // TODO: Try to make this a bit less of a random mishmash of functions.
      34             : 
      35             :   /// Find a "source" for some operation, which will be used in one of the
      36             :   /// operation's operands. This either selects an instruction in \c Insts or
      37             :   /// returns some new arbitrary Value.
      38             :   Value *findOrCreateSource(BasicBlock &BB, ArrayRef<Instruction *> Insts);
      39             :   /// Find a "source" for some operation, which will be used in one of the
      40             :   /// operation's operands. This either selects an instruction in \c Insts that
      41             :   /// matches \c Pred, or returns some new Value that matches \c Pred. The
      42             :   /// values in \c Srcs should be source operands that have already been
      43             :   /// selected.
      44             :   Value *findOrCreateSource(BasicBlock &BB, ArrayRef<Instruction *> Insts,
      45             :                             ArrayRef<Value *> Srcs, fuzzerop::SourcePred Pred);
      46             :   /// Create some Value suitable as a source for some operation.
      47             :   Value *newSource(BasicBlock &BB, ArrayRef<Instruction *> Insts,
      48             :                    ArrayRef<Value *> Srcs, fuzzerop::SourcePred Pred);
      49             :   /// Find a viable user for \c V in \c Insts, which should all be contained in
      50             :   /// \c BB. This may also create some new instruction in \c BB and use that.
      51             :   void connectToSink(BasicBlock &BB, ArrayRef<Instruction *> Insts, Value *V);
      52             :   /// Create a user for \c V in \c BB.
      53             :   void newSink(BasicBlock &BB, ArrayRef<Instruction *> Insts, Value *V);
      54             :   Value *findPointer(BasicBlock &BB, ArrayRef<Instruction *> Insts,
      55             :                      ArrayRef<Value *> Srcs, fuzzerop::SourcePred Pred);
      56             :   Type *chooseType(LLVMContext &Context, ArrayRef<Value *> Srcs,
      57             :                    fuzzerop::SourcePred Pred);
      58             : };
      59             : 
      60             : } // end llvm namespace
      61             : 
      62             : #endif // LLVM_FUZZMUTATE_RANDOMIRBUILDER_H