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Introduce FuzzMutate library

Browse Source 
This introduces the FuzzMutate library, which provides structured
fuzzing for LLVM IR, as described in my [EuroLLVM 2017 talk][1]. Most
of the basic mutators to inject and delete IR are provided, with
support for most basic operations.

I will follow up with the instruction selection fuzzer, which is
implemented in terms of this library.

[1]: http://llvm.org/devmtg/2017-03//2017/02/20/accepted-sessions.html#2

llvm-svn: 311356
This commit is contained in:
Justin Bogner 2017-08-21 17:44:36 +00:00
parent a00a3d6bcb
commit 480fdf7d03
16 changed files with 1623 additions and 0 deletions
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106
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//===-- IRMutator.h - Mutation engine for fuzzing 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 IRMutator class, which drives mutations on IR based on a
// configurable set of strategies. Some common strategies are also included
// here.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_FUZZMUTATE_IRMUTATOR_H
#define LLVM_FUZZMUTATE_IRMUTATOR_H
#include "llvm/FuzzMutate/OpDescriptor.h"
#include "llvm/Support/ErrorHandling.h"
namespace llvm {
class BasicBlock;
class Function;
class Instruction;
class Module;
struct RandomIRBuilder;
/// Base class for describing how to mutate a module. mutation functions for
/// each IR unit forward to the contained unit.
class IRMutationStrategy {
public:
virtual ~IRMutationStrategy() = default;
/// Provide a weight to bias towards choosing this strategy for a mutation.
///
/// The value of the weight is arbitrary, but a good default is "the number of
/// distinct ways in which this strategy can mutate a unit". This can also be
/// used to prefer strategies that shrink the overall size of the result when
/// we start getting close to \c MaxSize.
virtual uint64_t getWeight(size_t CurrentSize, size_t MaxSize,
uint64_t CurrentWeight) = 0;
/// @{
/// Mutators for each IR unit. By default these forward to a contained
/// instance of the next smaller unit.
virtual void mutate(Module &M, RandomIRBuilder &IB);
virtual void mutate(Function &F, RandomIRBuilder &IB);
virtual void mutate(BasicBlock &BB, RandomIRBuilder &IB);
virtual void mutate(Instruction &I, RandomIRBuilder &IB) {
llvm_unreachable("Strategy does not implement any mutators");
}
/// @}
};
using TypeGetter = std::function<Type *(LLVMContext &)>;
/// Entry point for configuring and running IR mutations.
class IRMutator {
std::vector<TypeGetter> AllowedTypes;
std::vector<std::unique_ptr<IRMutationStrategy>> Strategies;
public:
IRMutator(std::vector<TypeGetter> &&AllowedTypes,
std::vector<std::unique_ptr<IRMutationStrategy>> &&Strategies)
: AllowedTypes(std::move(AllowedTypes)),
Strategies(std::move(Strategies)) {}
void mutateModule(Module &M, int Seed, size_t CurSize, size_t MaxSize);
};
/// Strategy that injects operations into the function.
class InjectorIRStrategy : public IRMutationStrategy {
std::vector<fuzzerop::OpDescriptor> Operations;
fuzzerop::OpDescriptor chooseOperation(Value *Src, RandomIRBuilder &IB);
public:
InjectorIRStrategy(std::vector<fuzzerop::OpDescriptor> &&Operations)
: Operations(std::move(Operations)) {}
static std::vector<fuzzerop::OpDescriptor> getDefaultOps();
uint64_t getWeight(size_t CurrentSize, size_t MaxSize,
uint64_t CurrentWeight) override {
return Operations.size();
}
using IRMutationStrategy::mutate;
void mutate(Function &F, RandomIRBuilder &IB) override;
void mutate(BasicBlock &BB, RandomIRBuilder &IB) override;
};
class InstDeleterIRStrategy : public IRMutationStrategy {
public:
uint64_t getWeight(size_t CurrentSize, size_t MaxSize,
uint64_t CurrentWeight) override;
using IRMutationStrategy::mutate;
void mutate(Function &F, RandomIRBuilder &IB) override;
void mutate(Instruction &Inst, RandomIRBuilder &IB) override;
};
} // end llvm namespace
#endif // LLVM_FUZZMUTATE_IRMUTATOR_H

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//===-- OpDescriptor.h ------------------------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Provides the fuzzerop::Descriptor class and related tools for describing
// operations an IR fuzzer can work with.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_FUZZMUTATE_OPDESCRIPTOR_H
#define LLVM_FUZZMUTATE_OPDESCRIPTOR_H
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Type.h"
#include "llvm/IR/Value.h"
#include <functional>
namespace llvm {
namespace fuzzerop {
/// @{
/// Populate a small list of potentially interesting constants of a given type.
void makeConstantsWithType(Type *T, std::vector<Constant *> &Cs);
std::vector<Constant *> makeConstantsWithType(Type *T);
/// @}
/// A matcher/generator for finding suitable values for the next source in an
/// operation's partially completed argument list.
///
/// Given that we're building some operation X and may have already filled some
/// subset of its operands, this predicate determines if some value New is
/// suitable for the next operand or generates a set of values that are
/// suitable.
class SourcePred {
public:
/// Given a list of already selected operands, returns whether a given new
/// operand is suitable for the next operand.
using PredT = std::function<bool(ArrayRef<Value *> Cur, const Value *New)>;
/// Given a list of already selected operands and a set of valid base types
/// for a fuzzer, generates a list of constants that could be used for the
/// next operand.
using MakeT = std::function<std::vector<Constant *>(
ArrayRef<Value *> Cur, ArrayRef<Type *> BaseTypes)>;
private:
PredT Pred;
MakeT Make;
public:
/// Create a fully general source predicate.
SourcePred(PredT Pred, MakeT Make) : Pred(Pred), Make(Make) {}
SourcePred(PredT Pred, NoneType) : Pred(Pred) {
Make = [Pred](ArrayRef<Value *> Cur, ArrayRef<Type *> BaseTypes) {
// Default filter just calls Pred on each of the base types.
std::vector<Constant *> Result;
for (Type *T : BaseTypes) {
Constant *V = UndefValue::get(T);
if (Pred(Cur, V))
makeConstantsWithType(T, Result);
}
if (Result.empty())
report_fatal_error("Predicate does not match for base types");
return Result;
};
}
/// Returns true if \c New is compatible for the argument after \c Cur
bool matches(ArrayRef<Value *> Cur, const Value *New) {
return Pred(Cur, New);
}
/// Generates a list of potential values for the argument after \c Cur.
std::vector<Constant *> generate(ArrayRef<Value *> Cur,
ArrayRef<Type *> BaseTypes) {
return Make(Cur, BaseTypes);
}
};
/// A description of some operation we can build while fuzzing IR.
struct OpDescriptor {
unsigned Weight;
SmallVector<SourcePred, 2> SourcePreds;
std::function<Value *(ArrayRef<Value *>, Instruction *)> BuilderFunc;
};
static inline SourcePred onlyType(Type *Only) {
auto Pred = [Only](ArrayRef<Value *>, const Value *V) {
return V->getType() == Only;
};
auto Make = [Only](ArrayRef<Value *>, ArrayRef<Type *>) {
return makeConstantsWithType(Only);
};
return {Pred, Make};
}
static inline SourcePred anyType() {
auto Pred = [](ArrayRef<Value *>, const Value *V) {
return !V->getType()->isVoidTy();
};
auto Make = None;
return {Pred, Make};
}
static inline SourcePred anyIntType() {
auto Pred = [](ArrayRef<Value *>, const Value *V) {
return V->getType()->isIntegerTy();
};
auto Make = None;
return {Pred, Make};
}
static inline SourcePred anyFloatType() {
auto Pred = [](ArrayRef<Value *>, const Value *V) {
return V->getType()->isFloatingPointTy();
};
auto Make = None;
return {Pred, Make};
}
static inline SourcePred anyPtrType() {
auto Pred = [](ArrayRef<Value *>, const Value *V) {
return V->getType()->isPointerTy();
};
auto Make = [](ArrayRef<Value *>, ArrayRef<Type *> Ts) {
std::vector<Constant *> Result;
// TODO: Should these point at something?
for (Type *T : Ts)
Result.push_back(UndefValue::get(PointerType::getUnqual(T)));
return Result;
};
return {Pred, Make};
}
static inline SourcePred anyAggregateType() {
auto Pred = [](ArrayRef<Value *>, const Value *V) {
return V->getType()->isAggregateType();
};
// TODO: For now we only find aggregates in BaseTypes. It might be better to
// manufacture them out of the base types in some cases.
auto Find = None;
return {Pred, Find};
}
static inline SourcePred anyVectorType() {
auto Pred = [](ArrayRef<Value *>, const Value *V) {
return V->getType()->isVectorTy();
};
// TODO: For now we only find vectors in BaseTypes. It might be better to
// manufacture vectors out of the base types, but it's tricky to be sure
// that's actually a reasonable type.
auto Make = None;
return {Pred, Make};
}
/// Match values that have the same type as the first source.
static inline SourcePred matchFirstType() {
auto Pred = [](ArrayRef<Value *> Cur, const Value *V) {
assert(!Cur.empty() && "No first source yet");
return V->getType() == Cur[0]->getType();
};
auto Make = [](ArrayRef<Value *> Cur, ArrayRef<Type *>) {
assert(!Cur.empty() && "No first source yet");
return makeConstantsWithType(Cur[0]->getType());
};
return {Pred, Make};
}
/// Match values that have the first source's scalar type.
static inline SourcePred matchScalarOfFirstType() {
auto Pred = [](ArrayRef<Value *> Cur, const Value *V) {
assert(!Cur.empty() && "No first source yet");
return V->getType() == Cur[0]->getType()->getScalarType();
};
auto Make = [](ArrayRef<Value *> Cur, ArrayRef<Type *>) {
assert(!Cur.empty() && "No first source yet");
return makeConstantsWithType(Cur[0]->getType()->getScalarType());
};
return {Pred, Make};
}
} // end fuzzerop namespace
} // end llvm namespace
#endif // LLVM_FUZZMUTATE_OPDESCRIPTOR_H

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//===-- Operations.h - ----------------------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Implementations of common fuzzer operation descriptors for building an IR
// mutator.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_FUZZMUTATE_OPERATIONS_H
#define LLVM_FUZZMUTATE_OPERATIONS_H
#include "llvm/FuzzMutate/OpDescriptor.h"
#include "llvm/IR/InstrTypes.h"
#include "llvm/IR/Instruction.h"
namespace llvm {
/// Getters for the default sets of operations, per general category.
/// @{
void describeFuzzerIntOps(std::vector<fuzzerop::OpDescriptor> &Ops);
void describeFuzzerFloatOps(std::vector<fuzzerop::OpDescriptor> &Ops);
void describeFuzzerControlFlowOps(std::vector<fuzzerop::OpDescriptor> &Ops);
void describeFuzzerPointerOps(std::vector<fuzzerop::OpDescriptor> &Ops);
void describeFuzzerAggregateOps(std::vector<fuzzerop::OpDescriptor> &Ops);
void describeFuzzerVectorOps(std::vector<fuzzerop::OpDescriptor> &Ops);
/// @}
namespace fuzzerop {
/// Descriptors for individual operations.
/// @{
OpDescriptor binOpDescriptor(unsigned Weight, Instruction::BinaryOps Op);
OpDescriptor cmpOpDescriptor(unsigned Weight, Instruction::OtherOps CmpOp,
CmpInst::Predicate Pred);
OpDescriptor splitBlockDescriptor(unsigned Weight);
OpDescriptor gepDescriptor(unsigned Weight);
OpDescriptor extractValueDescriptor(unsigned Weight);
OpDescriptor insertValueDescriptor(unsigned Weight);
OpDescriptor extractElementDescriptor(unsigned Weight);
OpDescriptor insertElementDescriptor(unsigned Weight);
OpDescriptor shuffleVectorDescriptor(unsigned Weight);
/// @}
} // end fuzzerop namespace
} // end llvm namespace
#endif // LLVM_FUZZMUTATE_OPERATIONS_H

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//===--- Random.h - Utilities for random sampling -------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Utilities for random sampling.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_FUZZMUTATE_RANDOM_H
#define LLVM_FUZZMUTATE_RANDOM_H
#include <random>
#include "llvm/Support/raw_ostream.h"
namespace llvm {
/// Return a uniformly distributed random value between \c Min and \c Max
template <typename T, typename GenT> T uniform(GenT &Gen, T Min, T Max) {
return std::uniform_int_distribution<T>(Min, Max)(Gen);
}
/// Return a uniformly distributed random value of type \c T
template <typename T, typename GenT> T uniform(GenT &Gen) {
return uniform<T>(Gen, std::numeric_limits<T>::min(),
std::numeric_limits<T>::max());
}
/// Randomly selects an item by sampling into a set with an unknown number of
/// elements, which may each be weighted to be more likely choices.
template <typename T, typename GenT> class ReservoirSampler {
GenT &RandGen;
typename std::remove_const<T>::type Selection = {};
uint64_t TotalWeight = 0;
public:
ReservoirSampler(GenT &RandGen) : RandGen(RandGen) {}
uint64_t totalWeight() const { return TotalWeight; }
bool isEmpty() const { return TotalWeight == 0; }
const T &getSelection() const {
assert(!isEmpty() && "Nothing selected");
return Selection;
}
explicit operator bool() const { return !isEmpty();}
const T &operator*() const { return getSelection(); }
/// Sample each item in \c Items with unit weight
template <typename RangeT> ReservoirSampler &sample(RangeT &&Items) {
for (auto &I : Items)
sample(I, 1);
return *this;
}
/// Sample a single item with the given weight.
ReservoirSampler &sample(const T &Item, uint64_t Weight) {
if (!Weight)
// If the weight is zero, do nothing.
return *this;
TotalWeight += Weight;
// Consider switching from the current element to this one.
if (uniform<uint64_t>(RandGen, 1, TotalWeight) <= Weight)
Selection = Item;
return *this;
}
};
template <typename GenT, typename RangeT,
typename ElT = typename std::remove_reference<
decltype(*std::begin(std::declval<RangeT>()))>::type>
ReservoirSampler<ElT, GenT> makeSampler(GenT &RandGen, RangeT &&Items) {
ReservoirSampler<ElT, GenT> RS(RandGen);
RS.sample(Items);
return RS;
}
template <typename GenT, typename T>
ReservoirSampler<T, GenT> makeSampler(GenT &RandGen, const T &Item,
uint64_t Weight) {
ReservoirSampler<T, GenT> RS(RandGen);
RS.sample(Item, Weight);
return RS;
}
template <typename T, typename GenT>
ReservoirSampler<T, GenT> makeSampler(GenT &RandGen) {
return ReservoirSampler<T, GenT>(RandGen);
}
} // End llvm namespace
#endif // LLVM_FUZZMUTATE_RANDOM_H

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//===-- 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

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# CMakeLists.txt
add_subdirectory(IR)
add_subdirectory(FuzzMutate)
add_subdirectory(IRReader)
add_subdirectory(CodeGen)
add_subdirectory(BinaryFormat)

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add_llvm_library(LLVMFuzzMutate
IRMutator.cpp
OpDescriptor.cpp
Operations.cpp
RandomIRBuilder.cpp
ADDITIONAL_HEADER_DIRS
${LLVM_MAIN_INCLUDE_DIR}/llvm/FuzzMutate
DEPENDS
intrinsics_gen
)

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//===-- IRMutator.cpp -----------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/FuzzMutate/IRMutator.h"
#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/FuzzMutate/Operations.h"
#include "llvm/FuzzMutate/Random.h"
#include "llvm/FuzzMutate/RandomIRBuilder.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/InstIterator.h"
#include "llvm/IR/Module.h"
#include "llvm/Transforms/Scalar/DCE.h"
using namespace llvm;
static void createEmptyFunction(Module &M) {
// TODO: Some arguments and a return value would probably be more interesting.
LLVMContext &Context = M.getContext();
Function *F = Function::Create(FunctionType::get(Type::getVoidTy(Context), {},
/*isVarArg=*/false),
GlobalValue::ExternalLinkage, "f", &M);
BasicBlock *BB = BasicBlock::Create(Context, "BB", F);
ReturnInst::Create(Context, BB);
}
void IRMutationStrategy::mutate(Module &M, RandomIRBuilder &IB) {
if (M.empty())
createEmptyFunction(M);
auto RS = makeSampler<Function *>(IB.Rand);
for (Function &F : M)
if (!F.isDeclaration())
RS.sample(&F, /*Weight=*/1);
mutate(*RS.getSelection(), IB);
}
void IRMutationStrategy::mutate(Function &F, RandomIRBuilder &IB) {
mutate(*makeSampler(IB.Rand, make_pointer_range(F)).getSelection(), IB);
}
void IRMutationStrategy::mutate(BasicBlock &BB, RandomIRBuilder &IB) {
mutate(*makeSampler(IB.Rand, make_pointer_range(BB)).getSelection(), IB);
}
void IRMutator::mutateModule(Module &M, int Seed, size_t CurSize,
size_t MaxSize) {
std::vector<Type *> Types;
for (const auto &Getter : AllowedTypes)
Types.push_back(Getter(M.getContext()));
RandomIRBuilder IB(Seed, Types);
auto RS = makeSampler<IRMutationStrategy *>(IB.Rand);
for (const auto &Strategy : Strategies)
RS.sample(Strategy.get(),
Strategy->getWeight(CurSize, MaxSize, RS.totalWeight()));
auto Strategy = RS.getSelection();
Strategy->mutate(M, IB);
}
static void eliminateDeadCode(Function &F) {
FunctionPassManager FPM;
FPM.addPass(DCEPass());
FunctionAnalysisManager FAM;
FAM.registerPass([&] { return TargetLibraryAnalysis(); });
FPM.run(F, FAM);
}
void InjectorIRStrategy::mutate(Function &F, RandomIRBuilder &IB) {
IRMutationStrategy::mutate(F, IB);
eliminateDeadCode(F);
}
std::vector<fuzzerop::OpDescriptor> InjectorIRStrategy::getDefaultOps() {
std::vector<fuzzerop::OpDescriptor> Ops;
describeFuzzerIntOps(Ops);
describeFuzzerFloatOps(Ops);
describeFuzzerControlFlowOps(Ops);
describeFuzzerPointerOps(Ops);
describeFuzzerAggregateOps(Ops);
describeFuzzerVectorOps(Ops);
return Ops;
}
fuzzerop::OpDescriptor
InjectorIRStrategy::chooseOperation(Value *Src, RandomIRBuilder &IB) {
auto OpMatchesPred = [&Src](fuzzerop::OpDescriptor &Op) {
return Op.SourcePreds[0].matches({}, Src);
};
auto RS = makeSampler(IB.Rand, make_filter_range(Operations, OpMatchesPred));
if (RS.isEmpty())
report_fatal_error("No available operations for src type");
return *RS;
}
void InjectorIRStrategy::mutate(BasicBlock &BB, RandomIRBuilder &IB) {
SmallVector<Instruction *, 32> Insts;
for (auto I = BB.getFirstInsertionPt(), E = BB.end(); I != E; ++I)
Insts.push_back(&*I);
// Choose an insertion point for our new instruction.
size_t IP = uniform<size_t>(IB.Rand, 0, Insts.size() - 1);
auto InstsBefore = makeArrayRef(Insts).slice(0, IP);
auto InstsAfter = makeArrayRef(Insts).slice(IP);
// Choose a source, which will be used to constrain the operation selection.
SmallVector<Value *, 2> Srcs;
Srcs.push_back(IB.findOrCreateSource(BB, InstsBefore));
// Choose an operation that's constrained to be valid for the type of the
// source, collect any other sources it needs, and then build it.
fuzzerop::OpDescriptor OpDesc = chooseOperation(Srcs[0], IB);
for (const auto &Pred : makeArrayRef(OpDesc.SourcePreds).slice(1))
Srcs.push_back(IB.findOrCreateSource(BB, InstsBefore, Srcs, Pred));
if (Value *Op = OpDesc.BuilderFunc(Srcs, Insts[IP])) {
// Find a sink and wire up the results of the operation.
IB.connectToSink(BB, InstsAfter, Op);
}
}
uint64_t InstDeleterIRStrategy::getWeight(size_t CurrentSize, size_t MaxSize,
uint64_t CurrentWeight) {
// If we have less than 200 bytes, panic and try to always delete.
if (CurrentSize > MaxSize - 200)
return CurrentWeight ? CurrentWeight * 100 : 1;
// Draw a line starting from when we only have 1k left and increasing linearly
// to double the current weight.
int Line = (-2 * CurrentWeight) * (MaxSize - CurrentSize + 1000);
// Clamp negative weights to zero.
if (Line < 0)
return 0;
return Line;
}
void InstDeleterIRStrategy::mutate(Function &F, RandomIRBuilder &IB) {
auto RS = makeSampler<Instruction *>(IB.Rand);
// Avoid terminators so we don't have to worry about keeping the CFG coherent.
for (Instruction &Inst : instructions(F))
if (!Inst.isTerminator())
RS.sample(&Inst, /*Weight=*/1);
assert(!RS.isEmpty() && "No instructions to delete");
// Delete the instruction.
mutate(*RS.getSelection(), IB);
// Clean up any dead code that's left over after removing the instruction.
eliminateDeadCode(F);
}
void InstDeleterIRStrategy::mutate(Instruction &Inst, RandomIRBuilder &IB) {
assert(!Inst.isTerminator() && "Deleting terminators invalidates CFG");
if (Inst.getType()->isVoidTy()) {
// Instructions with void type (ie, store) have no uses to worry about. Just
// erase it and move on.
Inst.eraseFromParent();
return;
}
// Otherwise we need to find some other value with the right type to keep the
// users happy.
auto Pred = fuzzerop::onlyType(Inst.getType());
auto RS = makeSampler<Value *>(IB.Rand);
SmallVector<Instruction *, 32> InstsBefore;
BasicBlock *BB = Inst.getParent();
for (auto I = BB->getFirstInsertionPt(), E = Inst.getIterator(); I != E;
++I) {
if (Pred.matches({}, &*I))
RS.sample(&*I, /*Weight=*/1);
InstsBefore.push_back(&*I);
}
if (!RS)
RS.sample(IB.newSource(*BB, InstsBefore, {}, Pred), /*Weight=*/1);
Inst.replaceAllUsesWith(RS.getSelection());
}

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;===- ./lib/FuzzMutate/LLVMBuild.txt ---------------------------*- Conf -*--===;
;
; The LLVM Compiler Infrastructure
;
; This file is distributed under the University of Illinois Open Source
; License. See LICENSE.TXT for details.
;
;===------------------------------------------------------------------------===;
;
; This is an LLVMBuild description file for the components in this subdirectory.
;
; For more information on the LLVMBuild system, please see:
;
; http://llvm.org/docs/LLVMBuild.html
;
;===------------------------------------------------------------------------===;
[component_0]
type = Library
name = FuzzMutate
parent = Libraries
required_libraries = Analysis Core IR Support Transforms

38
lib/FuzzMutate/OpDescriptor.cpp Normal file
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//===-- OpDescriptor.cpp --------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/FuzzMutate/OpDescriptor.h"
#include "llvm/IR/Constants.h"
using namespace llvm;
using namespace fuzzerop;
void fuzzerop::makeConstantsWithType(Type *T, std::vector<Constant *> &Cs) {
if (auto *IntTy = dyn_cast<IntegerType>(T)) {
uint64_t W = IntTy->getBitWidth();
Cs.push_back(ConstantInt::get(IntTy, APInt::getMaxValue(W)));
Cs.push_back(ConstantInt::get(IntTy, APInt::getMinValue(W)));
Cs.push_back(ConstantInt::get(IntTy, APInt::getSignedMaxValue(W)));
Cs.push_back(ConstantInt::get(IntTy, APInt::getSignedMinValue(W)));
Cs.push_back(ConstantInt::get(IntTy, APInt::getOneBitSet(W, W / 2)));
} else if (T->isFloatingPointTy()) {
auto &Ctx = T->getContext();
auto &Sem = T->getFltSemantics();
Cs.push_back(ConstantFP::get(Ctx, APFloat::getZero(Sem)));
Cs.push_back(ConstantFP::get(Ctx, APFloat::getLargest(Sem)));
Cs.push_back(ConstantFP::get(Ctx, APFloat::getSmallest(Sem)));
} else
Cs.push_back(UndefValue::get(T));
}
std::vector<Constant *> fuzzerop::makeConstantsWithType(Type *T) {
std::vector<Constant *> Result;
makeConstantsWithType(T, Result);
return Result;
}

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//===-- Operations.cpp ----------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/FuzzMutate/Operations.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/Instructions.h"
using namespace llvm;
using namespace fuzzerop;
void llvm::describeFuzzerIntOps(std::vector<fuzzerop::OpDescriptor> &Ops) {
Ops.push_back(binOpDescriptor(1, Instruction::Add));
Ops.push_back(binOpDescriptor(1, Instruction::Sub));
Ops.push_back(binOpDescriptor(1, Instruction::Mul));
Ops.push_back(binOpDescriptor(1, Instruction::SDiv));
Ops.push_back(binOpDescriptor(1, Instruction::UDiv));
Ops.push_back(binOpDescriptor(1, Instruction::SRem));
Ops.push_back(binOpDescriptor(1, Instruction::URem));
Ops.push_back(binOpDescriptor(1, Instruction::Shl));
Ops.push_back(binOpDescriptor(1, Instruction::LShr));
Ops.push_back(binOpDescriptor(1, Instruction::AShr));
Ops.push_back(binOpDescriptor(1, Instruction::And));
Ops.push_back(binOpDescriptor(1, Instruction::Or));
Ops.push_back(binOpDescriptor(1, Instruction::Xor));
Ops.push_back(cmpOpDescriptor(1, Instruction::ICmp, CmpInst::ICMP_EQ));
Ops.push_back(cmpOpDescriptor(1, Instruction::ICmp, CmpInst::ICMP_NE));
Ops.push_back(cmpOpDescriptor(1, Instruction::ICmp, CmpInst::ICMP_UGT));
Ops.push_back(cmpOpDescriptor(1, Instruction::ICmp, CmpInst::ICMP_UGE));
Ops.push_back(cmpOpDescriptor(1, Instruction::ICmp, CmpInst::ICMP_ULT));
Ops.push_back(cmpOpDescriptor(1, Instruction::ICmp, CmpInst::ICMP_ULE));
Ops.push_back(cmpOpDescriptor(1, Instruction::ICmp, CmpInst::ICMP_SGT));
Ops.push_back(cmpOpDescriptor(1, Instruction::ICmp, CmpInst::ICMP_SGE));
Ops.push_back(cmpOpDescriptor(1, Instruction::ICmp, CmpInst::ICMP_SLT));
Ops.push_back(cmpOpDescriptor(1, Instruction::ICmp, CmpInst::ICMP_SLE));
}
void llvm::describeFuzzerFloatOps(std::vector<fuzzerop::OpDescriptor> &Ops) {
Ops.push_back(binOpDescriptor(1, Instruction::FAdd));
Ops.push_back(binOpDescriptor(1, Instruction::FSub));
Ops.push_back(binOpDescriptor(1, Instruction::FMul));
Ops.push_back(binOpDescriptor(1, Instruction::FDiv));
Ops.push_back(binOpDescriptor(1, Instruction::FRem));
Ops.push_back(cmpOpDescriptor(1, Instruction::FCmp, CmpInst::FCMP_FALSE));
Ops.push_back(cmpOpDescriptor(1, Instruction::FCmp, CmpInst::FCMP_OEQ));
Ops.push_back(cmpOpDescriptor(1, Instruction::FCmp, CmpInst::FCMP_OGT));
Ops.push_back(cmpOpDescriptor(1, Instruction::FCmp, CmpInst::FCMP_OGE));
Ops.push_back(cmpOpDescriptor(1, Instruction::FCmp, CmpInst::FCMP_OLT));
Ops.push_back(cmpOpDescriptor(1, Instruction::FCmp, CmpInst::FCMP_OLE));
Ops.push_back(cmpOpDescriptor(1, Instruction::FCmp, CmpInst::FCMP_ONE));
Ops.push_back(cmpOpDescriptor(1, Instruction::FCmp, CmpInst::FCMP_ORD));
Ops.push_back(cmpOpDescriptor(1, Instruction::FCmp, CmpInst::FCMP_UNO));
Ops.push_back(cmpOpDescriptor(1, Instruction::FCmp, CmpInst::FCMP_UEQ));
Ops.push_back(cmpOpDescriptor(1, Instruction::FCmp, CmpInst::FCMP_UGT));
Ops.push_back(cmpOpDescriptor(1, Instruction::FCmp, CmpInst::FCMP_UGE));
Ops.push_back(cmpOpDescriptor(1, Instruction::FCmp, CmpInst::FCMP_ULT));
Ops.push_back(cmpOpDescriptor(1, Instruction::FCmp, CmpInst::FCMP_ULE));
Ops.push_back(cmpOpDescriptor(1, Instruction::FCmp, CmpInst::FCMP_UNE));
Ops.push_back(cmpOpDescriptor(1, Instruction::FCmp, CmpInst::FCMP_TRUE));
}
void llvm::describeFuzzerControlFlowOps(
std::vector<fuzzerop::OpDescriptor> &Ops) {
Ops.push_back(splitBlockDescriptor(1));
}
void llvm::describeFuzzerPointerOps(std::vector<fuzzerop::OpDescriptor> &Ops) {
Ops.push_back(gepDescriptor(1));
}
void llvm::describeFuzzerAggregateOps(
std::vector<fuzzerop::OpDescriptor> &Ops) {
Ops.push_back(extractValueDescriptor(1));
Ops.push_back(insertValueDescriptor(1));
}
void llvm::describeFuzzerVectorOps(std::vector<fuzzerop::OpDescriptor> &Ops) {
Ops.push_back(extractElementDescriptor(1));
Ops.push_back(insertElementDescriptor(1));
Ops.push_back(shuffleVectorDescriptor(1));
}
OpDescriptor llvm::fuzzerop::binOpDescriptor(unsigned Weight,
Instruction::BinaryOps Op) {
auto buildOp = [Op](ArrayRef<Value *> Srcs, Instruction *Inst) {
return BinaryOperator::Create(Op, Srcs[0], Srcs[1], "B", Inst);
};
switch (Op) {
case Instruction::Add:
case Instruction::Sub:
case Instruction::Mul:
case Instruction::SDiv:
case Instruction::UDiv:
case Instruction::SRem:
case Instruction::URem:
case Instruction::Shl:
case Instruction::LShr:
case Instruction::AShr:
case Instruction::And:
case Instruction::Or:
case Instruction::Xor:
return {Weight, {anyIntType(), matchFirstType()}, buildOp};
case Instruction::FAdd:
case Instruction::FSub:
case Instruction::FMul:
case Instruction::FDiv:
case Instruction::FRem:
return {Weight, {anyFloatType(), matchFirstType()}, buildOp};
case Instruction::BinaryOpsEnd:
llvm_unreachable("Value out of range of enum");
}
llvm_unreachable("Covered switch");
}
OpDescriptor llvm::fuzzerop::cmpOpDescriptor(unsigned Weight,
Instruction::OtherOps CmpOp,
CmpInst::Predicate Pred) {
auto buildOp = [CmpOp, Pred](ArrayRef<Value *> Srcs, Instruction *Inst) {
return CmpInst::Create(CmpOp, Pred, Srcs[0], Srcs[1], "C", Inst);
};
switch (CmpOp) {
case Instruction::ICmp:
return {Weight, {anyIntType(), matchFirstType()}, buildOp};
case Instruction::FCmp:
return {Weight, {anyFloatType(), matchFirstType()}, buildOp};
default:
llvm_unreachable("CmpOp must be ICmp or FCmp");
}
}
OpDescriptor llvm::fuzzerop::splitBlockDescriptor(unsigned Weight) {
auto buildSplitBlock = [](ArrayRef<Value *> Srcs, Instruction *Inst) {
BasicBlock *Block = Inst->getParent();
BasicBlock *Next = Block->splitBasicBlock(Inst, "BB");
if (Block != &Block->getParent()->getEntryBlock()) {
// Loop back on this block by replacing the unconditional forward branch
// with a conditional with a backedge.
BranchInst::Create(Block, Next, Srcs[0], Block->getTerminator());
Block->getTerminator()->eraseFromParent();
// We need values for each phi in the block. Since there isn't a good way
// to do a variable number of input values currently, we just fill them
// with undef.
for (PHINode &PHI : Block->phis())
PHI.addIncoming(UndefValue::get(PHI.getType()), Block);
}
return nullptr;
};
SourcePred isInt1Ty{[](ArrayRef<Value *>, const Value *V) {
return V->getType()->isIntegerTy(1);
},
None};
return {Weight, {isInt1Ty}, buildSplitBlock};
}
OpDescriptor llvm::fuzzerop::gepDescriptor(unsigned Weight) {
auto buildGEP = [](ArrayRef<Value *> Srcs, Instruction *Inst) {
Type *Ty = cast<PointerType>(Srcs[0]->getType())->getElementType();
auto Indices = makeArrayRef(Srcs).drop_front(1);
return GetElementPtrInst::Create(Ty, Srcs[0], Indices, "G", Inst);
};
// TODO: Handle aggregates and vectors
// TODO: Support multiple indices.
// TODO: Try to avoid meaningless accesses.
return {Weight, {anyPtrType(), anyIntType()}, buildGEP};
}
static uint64_t getAggregateNumElements(Type *T) {
assert(T->isAggregateType() && "Not a struct or array");
if (isa<StructType>(T))
return T->getStructNumElements();
return T->getArrayNumElements();
}
static SourcePred validExtractValueIndex() {
auto Pred = [](ArrayRef<Value *> Cur, const Value *V) {
if (auto *CI = dyn_cast<ConstantInt>(V))
if (!CI->uge(getAggregateNumElements(Cur[0]->getType())))
return true;
return false;
};
auto Make = [](ArrayRef<Value *> Cur, ArrayRef<Type *> Ts) {
std::vector<Constant *> Result;
auto *Int32Ty = Type::getInt32Ty(Cur[0]->getContext());
uint64_t N = getAggregateNumElements(Cur[0]->getType());
// Create indices at the start, end, and middle, but avoid dups.
Result.push_back(ConstantInt::get(Int32Ty, 0));
if (N > 1)
Result.push_back(ConstantInt::get(Int32Ty, N - 1));
if (N > 2)
Result.push_back(ConstantInt::get(Int32Ty, N / 2));
return Result;
};
return {Pred, Make};
}
OpDescriptor llvm::fuzzerop::extractValueDescriptor(unsigned Weight) {
auto buildExtract = [](ArrayRef<Value *> Srcs, Instruction *Inst) {
// TODO: It's pretty inefficient to shuffle this all through constants.
unsigned Idx = cast<ConstantInt>(Srcs[1])->getZExtValue();
return ExtractValueInst::Create(Srcs[0], {Idx}, "E", Inst);
};
// TODO: Should we handle multiple indices?
return {Weight, {anyAggregateType(), validExtractValueIndex()}, buildExtract};
}
static SourcePred matchScalarInAggregate() {
auto Pred = [](ArrayRef<Value *> Cur, const Value *V) {
if (isa<ArrayType>(Cur[0]->getType()))
return V->getType() == Cur[0]->getType();
auto *STy = cast<StructType>(Cur[0]->getType());
for (int I = 0, E = STy->getNumElements(); I < E; ++I)
if (STy->getTypeAtIndex(I) == V->getType())
return true;
return false;
};
auto Make = [](ArrayRef<Value *> Cur, ArrayRef<Type *>) {
if (isa<ArrayType>(Cur[0]->getType()))
return makeConstantsWithType(Cur[0]->getType());
std::vector<Constant *> Result;
auto *STy = cast<StructType>(Cur[0]->getType());
for (int I = 0, E = STy->getNumElements(); I < E; ++I)
makeConstantsWithType(STy->getTypeAtIndex(I), Result);
return Result;
};
return {Pred, Make};
}
static SourcePred validInsertValueIndex() {
auto Pred = [](ArrayRef<Value *> Cur, const Value *V) {
auto *CTy = cast<CompositeType>(Cur[0]->getType());
if (auto *CI = dyn_cast<ConstantInt>(V))
if (CI->getBitWidth() == 32)
if (CTy->getTypeAtIndex(CI->getZExtValue()) == V->getType())
return true;
return false;
};
auto Make = [](ArrayRef<Value *> Cur, ArrayRef<Type *> Ts) {
std::vector<Constant *> Result;
auto *Int32Ty = Type::getInt32Ty(Cur[0]->getContext());
auto *CTy = cast<CompositeType>(Cur[0]->getType());
for (int I = 0, E = getAggregateNumElements(CTy); I < E; ++I)
if (CTy->getTypeAtIndex(I) == Cur[1]->getType())
Result.push_back(ConstantInt::get(Int32Ty, I));
return Result;
};
return {Pred, Make};
}
OpDescriptor llvm::fuzzerop::insertValueDescriptor(unsigned Weight) {
auto buildInsert = [](ArrayRef<Value *> Srcs, Instruction *Inst) {
// TODO: It's pretty inefficient to shuffle this all through constants.
unsigned Idx = cast<ConstantInt>(Srcs[2])->getZExtValue();
return InsertValueInst::Create(Srcs[0], Srcs[1], {Idx}, "I", Inst);
};
return {
Weight,
{anyAggregateType(), matchScalarInAggregate(), validInsertValueIndex()},
buildInsert};
}
OpDescriptor llvm::fuzzerop::extractElementDescriptor(unsigned Weight) {
auto buildExtract = [](ArrayRef<Value *> Srcs, Instruction *Inst) {
return ExtractElementInst::Create(Srcs[0], Srcs[1], "E", Inst);
};
// TODO: Try to avoid undefined accesses.
return {Weight, {anyVectorType(), anyIntType()}, buildExtract};
}
OpDescriptor llvm::fuzzerop::insertElementDescriptor(unsigned Weight) {
auto buildInsert = [](ArrayRef<Value *> Srcs, Instruction *Inst) {
return InsertElementInst::Create(Srcs[0], Srcs[1], Srcs[2], "I", Inst);
};
// TODO: Try to avoid undefined accesses.
return {Weight,
{anyVectorType(), matchScalarOfFirstType(), anyIntType()},
buildInsert};
}
static SourcePred validShuffleVectorIndex() {
auto Pred = [](ArrayRef<Value *> Cur, const Value *V) {
return ShuffleVectorInst::isValidOperands(Cur[0], Cur[1], V);
};
auto Make = [](ArrayRef<Value *> Cur, ArrayRef<Type *> Ts) {
auto *FirstTy = cast<VectorType>(Cur[0]->getType());
auto *Int32Ty = Type::getInt32Ty(Cur[0]->getContext());
// TODO: It's straighforward to make up reasonable values, but listing them
// exhaustively would be insane. Come up with a couple of sensible ones.
return std::vector<Constant *>{
UndefValue::get(VectorType::get(Int32Ty, FirstTy->getNumElements()))};
};
return {Pred, Make};
}
OpDescriptor llvm::fuzzerop::shuffleVectorDescriptor(unsigned Weight) {
auto buildShuffle = [](ArrayRef<Value *> Srcs, Instruction *Inst) {
return new ShuffleVectorInst(Srcs[0], Srcs[1], Srcs[2], "S", Inst);
};
return {Weight,
{anyVectorType(), matchFirstType(), validShuffleVectorIndex()},
buildShuffle};
}

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//===-- RandomIRBuilder.cpp -----------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/FuzzMutate/RandomIRBuilder.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/FuzzMutate/Random.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Module.h"
using namespace llvm;
using namespace fuzzerop;
Value *RandomIRBuilder::findOrCreateSource(BasicBlock &BB,
ArrayRef<Instruction *> Insts) {
return findOrCreateSource(BB, Insts, {}, anyType());
}
Value *RandomIRBuilder::findOrCreateSource(BasicBlock &BB,
ArrayRef<Instruction *> Insts,
ArrayRef<Value *> Srcs,
SourcePred Pred) {
auto MatchesPred = [&Srcs, &Pred](Instruction *Inst) {
return Pred.matches(Srcs, Inst);
};
auto RS = makeSampler(Rand, make_filter_range(Insts, MatchesPred));
// Also consider choosing no source, meaning we want a new one.
RS.sample(nullptr, /*Weight=*/1);
if (Instruction *Src = RS.getSelection())
return Src;
return newSource(BB, Insts, Srcs, Pred);
}
Value *RandomIRBuilder::newSource(BasicBlock &BB, ArrayRef<Instruction *> Insts,
ArrayRef<Value *> Srcs, SourcePred Pred) {
// Generate some constants to choose from.
auto RS = makeSampler<Value *>(Rand);
RS.sample(Pred.generate(Srcs, KnownTypes));
assert(!RS.isEmpty() && "Failed to generate sources");
// If we can find a pointer to load from, use it half the time.
Value *Ptr = findPointer(BB, Insts, Srcs, Pred);
if (Ptr)
RS.sample(Ptr, RS.totalWeight());
Value *Result = RS.getSelection();
if (Result != Ptr)
return Result;
// If we choose the pointer, we need to create a load.
auto IP = BB.getFirstInsertionPt();
if (auto *I = dyn_cast<Instruction>(Ptr))
IP = ++I->getIterator();
return new LoadInst(Ptr, "L", &*IP);
}
static bool isCompatibleReplacement(const Instruction *I, const Use &Operand,
const Value *Replacement) {
if (Operand->getType() != Replacement->getType())
return false;
switch (I->getOpcode()) {
case Instruction::GetElementPtr:
case Instruction::ExtractElement:
case Instruction::ExtractValue:
// TODO: We could potentially validate these, but for now just leave indices
// alone.
if (Operand.getOperandNo() > 1)
return false;
break;
case Instruction::InsertValue:
case Instruction::InsertElement:
if (Operand.getOperandNo() > 2)
return false;
break;
default:
break;
}
return true;
}
void RandomIRBuilder::connectToSink(BasicBlock &BB,
ArrayRef<Instruction *> Insts, Value *V) {
auto RS = makeSampler<Use *>(Rand);
for (auto &I : Insts) {
if (isa<IntrinsicInst>(I))
// TODO: Replacing operands of intrinsics would be interesting, but
// there's no easy way to verify that a given replacement is valid given
// that intrinsics can impose arbitrary constraints.
continue;
for (Use &U : I->operands())
if (isCompatibleReplacement(I, U, V))
RS.sample(&U, 1);
}
// Also consider choosing no sink, meaning we want a new one.
RS.sample(nullptr, /*Weight=*/1);
if (Use *Sink = RS.getSelection()) {
User *U = Sink->getUser();
unsigned OpNo = Sink->getOperandNo();
U->setOperand(OpNo, V);
return;
}
newSink(BB, Insts, V);
}
void RandomIRBuilder::newSink(BasicBlock &BB, ArrayRef<Instruction *> Insts,
Value *V) {
Value *Ptr = findPointer(BB, Insts, {V}, matchFirstType());
if (!Ptr) {
if (uniform<bool>(Rand))
Ptr = new AllocaInst(V->getType(), 0, "A", &*BB.getFirstInsertionPt());
else
Ptr = UndefValue::get(PointerType::get(V->getType(), 0));
}
new StoreInst(V, Ptr, Insts.back());
}
Value *RandomIRBuilder::findPointer(BasicBlock &BB,
ArrayRef<Instruction *> Insts,
ArrayRef<Value *> Srcs, SourcePred Pred) {
auto IsMatchingPtr = [&Srcs, &Pred](Instruction *Inst) {
if (auto PtrTy = dyn_cast<PointerType>(Inst->getType()))
// TODO: Check if this is horribly expensive.
return Pred.matches(Srcs, UndefValue::get(PtrTy->getElementType()));
return false;
};
if (auto RS = makeSampler(Rand, make_filter_range(Insts, IsMatchingPtr)))
return RS.getSelection();
return nullptr;
}

1
unittests/CMakeLists.txt
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@ -12,6 +12,7 @@ add_subdirectory(Bitcode)
add_subdirectory(CodeGen)
add_subdirectory(DebugInfo)
add_subdirectory(ExecutionEngine)
add_subdirectory(FuzzMutate)
add_subdirectory(IR)
add_subdirectory(LineEditor)
add_subdirectory(Linker)

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unittests/FuzzMutate/CMakeLists.txt Normal file
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@ -0,0 +1,10 @@
set(LLVM_LINK_COMPONENTS
Core
FuzzMutate
Support
)
add_llvm_unittest(FuzzMutateTests
OperationsTest.cpp
ReservoirSamplerTest.cpp
)

323
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//===- OperationsTest.cpp - Tests for fuzzer operations -------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/FuzzMutate/Operations.h"
#include "llvm/FuzzMutate/OpDescriptor.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Verifier.h"
#include "gmock/gmock.h"
#include "gtest/gtest.h"
#include <iostream>
// Define some pretty printers to help with debugging failures.
namespace llvm {
void PrintTo(Type *T, ::std::ostream *OS) {
raw_os_ostream ROS(*OS);
T->print(ROS);
}
void PrintTo(BasicBlock *BB, ::std::ostream *OS) {
raw_os_ostream ROS(*OS);
ROS << BB << " (" << BB->getName() << ")";
}
void PrintTo(Value *V, ::std::ostream *OS) {
raw_os_ostream ROS(*OS);
ROS << V << " (";
V->print(ROS);
ROS << ")";
}
void PrintTo(Constant *C, ::std::ostream *OS) { PrintTo(cast<Value>(C), OS); }
} // namespace llvm
using namespace llvm;
using testing::AllOf;
using testing::AnyOf;
using testing::ElementsAre;
using testing::Eq;
using testing::Ge;
using testing::Each;
using testing::Truly;
using testing::NotNull;
using testing::PrintToString;
using testing::SizeIs;
MATCHER_P(TypesMatch, V, "has type " + PrintToString(V->getType())) {
return arg->getType() == V->getType();
}
MATCHER_P(HasType, T, "") { return arg->getType() == T; }
TEST(OperationsTest, SourcePreds) {
using namespace llvm::fuzzerop;
LLVMContext Ctx;
Constant *i1 = ConstantInt::getFalse(Ctx);
Constant *i8 = ConstantInt::get(Type::getInt8Ty(Ctx), 3);
Constant *i16 = ConstantInt::get(Type::getInt16Ty(Ctx), 1 << 15);
Constant *i32 = ConstantInt::get(Type::getInt32Ty(Ctx), 0);
Constant *i64 = ConstantInt::get(Type::getInt64Ty(Ctx),
std::numeric_limits<uint64_t>::max());
Constant *f16 = ConstantFP::getInfinity(Type::getHalfTy(Ctx));
Constant *f32 = ConstantFP::get(Type::getFloatTy(Ctx), 0.0);
Constant *f64 = ConstantFP::get(Type::getDoubleTy(Ctx), 123.45);
Constant *s =
ConstantStruct::get(StructType::create(Ctx, "OpaqueStruct"));
Constant *a =
ConstantArray::get(ArrayType::get(i32->getType(), 2), {i32, i32});
Constant *v8i8 = ConstantVector::getSplat(8, i8);
Constant *v4f16 = ConstantVector::getSplat(4, f16);
Constant *p0i32 =
ConstantPointerNull::get(PointerType::get(i32->getType(), 0));
auto OnlyI32 = onlyType(i32->getType());
EXPECT_TRUE(OnlyI32.matches({}, i32));
EXPECT_FALSE(OnlyI32.matches({}, i64));
EXPECT_FALSE(OnlyI32.matches({}, p0i32));
EXPECT_FALSE(OnlyI32.matches({}, a));
EXPECT_THAT(OnlyI32.generate({}, {}),
AllOf(SizeIs(Ge(1u)), Each(TypesMatch(i32))));
auto AnyType = anyType();
EXPECT_TRUE(AnyType.matches({}, i1));
EXPECT_TRUE(AnyType.matches({}, f64));
EXPECT_TRUE(AnyType.matches({}, s));
EXPECT_TRUE(AnyType.matches({}, v8i8));
EXPECT_TRUE(AnyType.matches({}, p0i32));
EXPECT_THAT(
AnyType.generate({}, {i32->getType(), f16->getType(), v8i8->getType()}),
Each(AnyOf(TypesMatch(i32), TypesMatch(f16), TypesMatch(v8i8))));
auto AnyInt = anyIntType();
EXPECT_TRUE(AnyInt.matches({}, i1));
EXPECT_TRUE(AnyInt.matches({}, i64));
EXPECT_FALSE(AnyInt.matches({}, f32));
EXPECT_FALSE(AnyInt.matches({}, v4f16));
EXPECT_THAT(
AnyInt.generate({}, {i32->getType(), f16->getType(), v8i8->getType()}),
AllOf(SizeIs(Ge(1u)), Each(TypesMatch(i32))));
auto AnyFP = anyFloatType();
EXPECT_TRUE(AnyFP.matches({}, f16));
EXPECT_TRUE(AnyFP.matches({}, f32));
EXPECT_FALSE(AnyFP.matches({}, i16));
EXPECT_FALSE(AnyFP.matches({}, p0i32));
EXPECT_FALSE(AnyFP.matches({}, v4f16));
EXPECT_THAT(
AnyFP.generate({}, {i32->getType(), f16->getType(), v8i8->getType()}),
AllOf(SizeIs(Ge(1u)), Each(TypesMatch(f16))));
auto AnyPtr = anyPtrType();
EXPECT_TRUE(AnyPtr.matches({}, p0i32));
EXPECT_FALSE(AnyPtr.matches({}, i8));
EXPECT_FALSE(AnyPtr.matches({}, a));
EXPECT_FALSE(AnyPtr.matches({}, v8i8));
auto isPointer = [](Value *V) { return V->getType()->isPointerTy(); };
EXPECT_THAT(
AnyPtr.generate({}, {i32->getType(), f16->getType(), v8i8->getType()}),
AllOf(SizeIs(Ge(3u)), Each(Truly(isPointer))));
auto AnyVec = anyVectorType();
EXPECT_TRUE(AnyVec.matches({}, v8i8));
EXPECT_TRUE(AnyVec.matches({}, v4f16));
EXPECT_FALSE(AnyVec.matches({}, i8));
EXPECT_FALSE(AnyVec.matches({}, a));
EXPECT_FALSE(AnyVec.matches({}, s));
EXPECT_THAT(AnyVec.generate({}, {v8i8->getType()}),
ElementsAre(TypesMatch(v8i8)));
auto First = matchFirstType();
EXPECT_TRUE(First.matches({i8}, i8));
EXPECT_TRUE(First.matches({s, a}, s));
EXPECT_FALSE(First.matches({f16}, f32));
EXPECT_FALSE(First.matches({v4f16, f64}, f64));
EXPECT_THAT(First.generate({i8}, {}), Each(TypesMatch(i8)));
EXPECT_THAT(First.generate({f16}, {i8->getType()}),
Each(TypesMatch(f16)));
EXPECT_THAT(First.generate({v8i8, i32}, {}), Each(TypesMatch(v8i8)));
}
TEST(OperationsTest, SplitBlock) {
LLVMContext Ctx;
Module M("M", Ctx);
Function *F = Function::Create(FunctionType::get(Type::getVoidTy(Ctx), {},
/*isVarArg=*/false),
GlobalValue::ExternalLinkage, "f", &M);
auto SBOp = fuzzerop::splitBlockDescriptor(1);
// Create a block with only a return and split it on the return.
auto *BB = BasicBlock::Create(Ctx, "BB", F);
auto *RI = ReturnInst::Create(Ctx, BB);
SBOp.BuilderFunc({UndefValue::get(Type::getInt1Ty(Ctx))}, RI);
// We should end up with an unconditional branch from BB to BB1, and the
// return ends up in BB1.
auto *UncondBr = cast<BranchInst>(BB->getTerminator());
ASSERT_TRUE(UncondBr->isUnconditional());
auto *BB1 = UncondBr->getSuccessor(0);
ASSERT_THAT(RI->getParent(), Eq(BB1));
// Now add an instruction to BB1 and split on that.
auto *AI = new AllocaInst(Type::getInt8Ty(Ctx), 0, "a", RI);
Value *Cond = ConstantInt::getFalse(Ctx);
SBOp.BuilderFunc({Cond}, AI);
// We should end up with a loop back on BB1 and the instruction we split on
// moves to BB2.
auto *CondBr = cast<BranchInst>(BB1->getTerminator());
EXPECT_THAT(CondBr->getCondition(), Eq(Cond));
ASSERT_THAT(CondBr->getNumSuccessors(), Eq(2u));
ASSERT_THAT(CondBr->getSuccessor(0), Eq(BB1));
auto *BB2 = CondBr->getSuccessor(1);
EXPECT_THAT(AI->getParent(), Eq(BB2));
EXPECT_THAT(RI->getParent(), Eq(BB2));
EXPECT_FALSE(verifyModule(M, &errs()));
}
TEST(OperationsTest, SplitBlockWithPhis) {
LLVMContext Ctx;
Type *Int8Ty = Type::getInt8Ty(Ctx);
Module M("M", Ctx);
Function *F = Function::Create(FunctionType::get(Type::getVoidTy(Ctx), {},
/*isVarArg=*/false),
GlobalValue::ExternalLinkage, "f", &M);
auto SBOp = fuzzerop::splitBlockDescriptor(1);
// Create 3 blocks with an if-then branch.
auto *BB1 = BasicBlock::Create(Ctx, "BB1", F);
auto *BB2 = BasicBlock::Create(Ctx, "BB2", F);
auto *BB3 = BasicBlock::Create(Ctx, "BB3", F);
BranchInst::Create(BB2, BB3, ConstantInt::getFalse(Ctx), BB1);
BranchInst::Create(BB3, BB2);
// Set up phi nodes selecting values for the incoming edges.
auto *PHI1 = PHINode::Create(Int8Ty, /*NumReservedValues=*/2, "p1", BB3);
PHI1->addIncoming(ConstantInt::get(Int8Ty, 0), BB1);
PHI1->addIncoming(ConstantInt::get(Int8Ty, 1), BB2);
auto *PHI2 = PHINode::Create(Int8Ty, /*NumReservedValues=*/2, "p2", BB3);
PHI2->addIncoming(ConstantInt::get(Int8Ty, 1), BB1);
PHI2->addIncoming(ConstantInt::get(Int8Ty, 0), BB2);
auto *RI = ReturnInst::Create(Ctx, BB3);
// Now we split the block with PHI nodes, making sure they're all updated.
Value *Cond = ConstantInt::getFalse(Ctx);
SBOp.BuilderFunc({Cond}, RI);
// Make sure the PHIs are updated with a value for the third incoming edge.
EXPECT_THAT(PHI1->getNumIncomingValues(), Eq(3u));
EXPECT_THAT(PHI2->getNumIncomingValues(), Eq(3u));
EXPECT_FALSE(verifyModule(M, &errs()));
}
TEST(OperationsTest, GEP) {
LLVMContext Ctx;
Type *Int8PtrTy = Type::getInt8PtrTy(Ctx);
Type *Int32Ty = Type::getInt32Ty(Ctx);
Module M("M", Ctx);
Function *F = Function::Create(FunctionType::get(Type::getVoidTy(Ctx), {},
/*isVarArg=*/false),
GlobalValue::ExternalLinkage, "f", &M);
auto *BB = BasicBlock::Create(Ctx, "BB", F);
auto *RI = ReturnInst::Create(Ctx, BB);
auto GEPOp = fuzzerop::gepDescriptor(1);
EXPECT_TRUE(GEPOp.SourcePreds[0].matches({}, UndefValue::get(Int8PtrTy)));
EXPECT_TRUE(GEPOp.SourcePreds[1].matches({UndefValue::get(Int8PtrTy)},
ConstantInt::get(Int32Ty, 0)));
GEPOp.BuilderFunc({UndefValue::get(Int8PtrTy), ConstantInt::get(Int32Ty, 0)},
RI);
EXPECT_FALSE(verifyModule(M, &errs()));
}
TEST(OperationsTest, ExtractAndInsertValue) {
LLVMContext Ctx;
Type *Int8PtrTy = Type::getInt8PtrTy(Ctx);
Type *Int32Ty = Type::getInt32Ty(Ctx);
Type *Int64Ty = Type::getInt64Ty(Ctx);
Type *StructTy = StructType::create(Ctx, {Int8PtrTy, Int32Ty});
Type *OpaqueTy = StructType::create(Ctx, "OpaqueStruct");
Type *ArrayTy = ArrayType::get(Int64Ty, 4);
Type *VectorTy = VectorType::get(Int32Ty, 2);
auto EVOp = fuzzerop::extractValueDescriptor(1);
auto IVOp = fuzzerop::insertValueDescriptor(1);
// Sanity check the source preds.
Constant *SVal = UndefValue::get(StructTy);
Constant *OVal = UndefValue::get(OpaqueTy);
Constant *AVal = UndefValue::get(ArrayTy);
Constant *VVal = UndefValue::get(VectorTy);
EXPECT_TRUE(EVOp.SourcePreds[0].matches({}, SVal));
EXPECT_TRUE(EVOp.SourcePreds[0].matches({}, OVal));
EXPECT_TRUE(EVOp.SourcePreds[0].matches({}, AVal));
EXPECT_FALSE(EVOp.SourcePreds[0].matches({}, VVal));
EXPECT_TRUE(IVOp.SourcePreds[0].matches({}, SVal));
EXPECT_TRUE(IVOp.SourcePreds[0].matches({}, OVal));
EXPECT_TRUE(IVOp.SourcePreds[0].matches({}, AVal));
EXPECT_FALSE(IVOp.SourcePreds[0].matches({}, VVal));
// Make sure we're range checking appropriately.
EXPECT_TRUE(
EVOp.SourcePreds[1].matches({SVal}, ConstantInt::get(Int32Ty, 0)));
EXPECT_TRUE(
EVOp.SourcePreds[1].matches({SVal}, ConstantInt::get(Int32Ty, 1)));
EXPECT_FALSE(
EVOp.SourcePreds[1].matches({SVal}, ConstantInt::get(Int32Ty, 2)));
EXPECT_FALSE(
EVOp.SourcePreds[1].matches({OVal}, ConstantInt::get(Int32Ty, 0)));
EXPECT_FALSE(
EVOp.SourcePreds[1].matches({OVal}, ConstantInt::get(Int32Ty, 65536)));
EXPECT_TRUE(
EVOp.SourcePreds[1].matches({AVal}, ConstantInt::get(Int32Ty, 0)));
EXPECT_TRUE(
EVOp.SourcePreds[1].matches({AVal}, ConstantInt::get(Int32Ty, 3)));
EXPECT_FALSE(
EVOp.SourcePreds[1].matches({AVal}, ConstantInt::get(Int32Ty, 4)));
EXPECT_THAT(
EVOp.SourcePreds[1].generate({SVal}, {}),
ElementsAre(ConstantInt::get(Int32Ty, 0), ConstantInt::get(Int32Ty, 1)));
// InsertValue should accept any type in the struct, but only in positions
// where it makes sense.
EXPECT_TRUE(IVOp.SourcePreds[1].matches({SVal}, UndefValue::get(Int8PtrTy)));
EXPECT_TRUE(IVOp.SourcePreds[1].matches({SVal}, UndefValue::get(Int32Ty)));
EXPECT_FALSE(IVOp.SourcePreds[1].matches({SVal}, UndefValue::get(Int64Ty)));
EXPECT_FALSE(IVOp.SourcePreds[2].matches({SVal, UndefValue::get(Int32Ty)},
ConstantInt::get(Int32Ty, 0)));
EXPECT_TRUE(IVOp.SourcePreds[2].matches({SVal, UndefValue::get(Int32Ty)},
ConstantInt::get(Int32Ty, 1)));
EXPECT_THAT(IVOp.SourcePreds[1].generate({SVal}, {}),
Each(AnyOf(HasType(Int32Ty), HasType(Int8PtrTy))));
EXPECT_THAT(
IVOp.SourcePreds[2].generate({SVal, ConstantInt::get(Int32Ty, 0)}, {}),
ElementsAre(ConstantInt::get(Int32Ty, 1)));
}

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//===- ReservoirSampler.cpp - Tests for the ReservoirSampler --------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/FuzzMutate/Random.h"
#include "gtest/gtest.h"
#include <random>
using namespace llvm;
TEST(ReservoirSamplerTest, OneItem) {
std::mt19937 Rand;
auto Sampler = makeSampler(Rand, 7, 1);
ASSERT_FALSE(Sampler.isEmpty());
ASSERT_EQ(7, Sampler.getSelection());
}
TEST(ReservoirSamplerTest, NoWeight) {
std::mt19937 Rand;
auto Sampler = makeSampler(Rand, 7, 0);
ASSERT_TRUE(Sampler.isEmpty());
}
TEST(ReservoirSamplerTest, Uniform) {
std::mt19937 Rand;
// Run three chi-squared tests to check that the distribution is reasonably
// uniform.
std::vector<int> Items = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
int Failures = 0;
for (int Run = 0; Run < 3; ++Run) {
std::vector<int> Counts(Items.size(), 0);
// We need $np_s > 5$ at minimum, but we're better off going a couple of
// orders of magnitude larger.
int N = Items.size() * 5 * 100;
for (int I = 0; I < N; ++I) {
auto Sampler = makeSampler(Rand, Items);
Counts[Sampler.getSelection()] += 1;
}
// Knuth. TAOCP Vol. 2, 3.3.1 (8):
// $V = \frac{1}{n} \sum_{s=1}^{k} \left(\frac{Y_s^2}{p_s}\right) - n$
double Ps = 1.0 / Items.size();
double Sum = 0.0;
for (int Ys : Counts)
Sum += Ys * Ys / Ps;
double V = (Sum / N) - N;
assert(Items.size() == 10 && "Our chi-squared values assume 10 items");
// Since we have 10 items, there are 9 degrees of freedom and the table of
// chi-squared values is as follows:
//
// | p=1% | 5% | 25% | 50% | 75% | 95% | 99% |
// v=9 | 2.088 | 3.325 | 5.899 | 8.343 | 11.39 | 16.92 | 21.67 |
//
// Check that we're in the likely range of results.
//if (V < 2.088 || V > 21.67)
if (V < 2.088 || V > 21.67)
++Failures;
}
EXPECT_LT(Failures, 3) << "Non-uniform distribution?";
}