1 //===- RandomIRBuilder.h - Utils for randomly mutation IR -------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // Provides the Mutator class, which is used to mutate IR for fuzzing.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef LLVM_FUZZMUTATE_RANDOMIRBUILDER_H
14 #define LLVM_FUZZMUTATE_RANDOMIRBUILDER_H
15 
16 #include "llvm/ADT/SmallPtrSet.h"
17 #include "llvm/FuzzMutate/IRMutator.h"
18 #include "llvm/FuzzMutate/Random.h"
19 #include <random>
20 
21 namespace llvm {
22 
23 using RandomEngine = std::mt19937;
24 
25 struct RandomIRBuilder {
26   RandomEngine Rand;
27   SmallVector<Type *, 16> KnownTypes;
28 
RandomIRBuilderRandomIRBuilder29   RandomIRBuilder(int Seed, ArrayRef<Type *> AllowedTypes)
30       : Rand(Seed), KnownTypes(AllowedTypes.begin(), AllowedTypes.end()) {}
31 
32   // TODO: Try to make this a bit less of a random mishmash of functions.
33 
34   /// Find a "source" for some operation, which will be used in one of the
35   /// operation's operands. This either selects an instruction in \c Insts or
36   /// returns some new arbitrary Value.
37   Value *findOrCreateSource(BasicBlock &BB, ArrayRef<Instruction *> Insts);
38   /// Find a "source" for some operation, which will be used in one of the
39   /// operation's operands. This either selects an instruction in \c Insts that
40   /// matches \c Pred, or returns some new Value that matches \c Pred. The
41   /// values in \c Srcs should be source operands that have already been
42   /// selected.
43   Value *findOrCreateSource(BasicBlock &BB, ArrayRef<Instruction *> Insts,
44                             ArrayRef<Value *> Srcs, fuzzerop::SourcePred Pred);
45   /// Create some Value suitable as a source for some operation.
46   Value *newSource(BasicBlock &BB, ArrayRef<Instruction *> Insts,
47                    ArrayRef<Value *> Srcs, fuzzerop::SourcePred Pred);
48   /// Find a viable user for \c V in \c Insts, which should all be contained in
49   /// \c BB. This may also create some new instruction in \c BB and use that.
50   void connectToSink(BasicBlock &BB, ArrayRef<Instruction *> Insts, Value *V);
51   /// Create a user for \c V in \c BB.
52   void newSink(BasicBlock &BB, ArrayRef<Instruction *> Insts, Value *V);
53   Value *findPointer(BasicBlock &BB, ArrayRef<Instruction *> Insts,
54                      ArrayRef<Value *> Srcs, fuzzerop::SourcePred Pred);
55   Type *chooseType(LLVMContext &Context, ArrayRef<Value *> Srcs,
56                    fuzzerop::SourcePred Pred);
57 };
58 
59 } // end llvm namespace
60 
61 #endif // LLVM_FUZZMUTATE_RANDOMIRBUILDER_H
62