}
size_t Fuzzer::RunOneMaximizeTotalCoverage(const Unit &U) {
+ size_t NumCounters = __sanitizer_get_number_of_counters();
+ if (Options.UseCounters) {
+ CounterBitmap.resize(NumCounters);
+ __sanitizer_update_counter_bitset_and_clear_counters(0);
+ }
size_t OldCoverage = __sanitizer_get_total_unique_coverage();
Callback(U.data(), U.size());
size_t NewCoverage = __sanitizer_get_total_unique_coverage();
+ size_t NumNewBits = 0;
+ if (Options.UseCounters)
+ NumNewBits = __sanitizer_update_counter_bitset_and_clear_counters(
+ CounterBitmap.data());
+
if (!(TotalNumberOfRuns & (TotalNumberOfRuns - 1)) && Options.Verbosity) {
size_t Seconds = secondsSinceProcessStartUp();
std::cerr
<< "#" << TotalNumberOfRuns
<< "\tcov: " << NewCoverage
+ << "\tbits: " << TotalBits()
<< "\texec/s: " << (Seconds ? TotalNumberOfRuns / Seconds : 0) << "\n";
}
- if (NewCoverage > OldCoverage)
+ if (NewCoverage > OldCoverage || NumNewBits)
return NewCoverage;
return 0;
}
if (Options.Verbosity) {
std::cerr << "#" << TotalNumberOfRuns
<< "\tNEW: " << NewCoverage
+ << " B: " << TotalBits()
<< " L: " << U->size()
<< " S: " << Corpus.size()
<< " I: " << i
"callbacks at every basic block"),
cl::Hidden, cl::init(false));
+// Experimental 8-bit counters used as an additional search heuristic during
+// coverage-guided fuzzing.
+// The counters are not thread-friendly:
+// - contention on these counters may cause significant slowdown;
+// - the counter updates are racy and the results may be inaccurate.
+// They are also inaccurate due to 8-bit integer overflow.
+static cl::opt<bool> ClUse8bitCounters("sanitizer-coverage-8bit-counters",
+ cl::desc("Experimental 8-bit counters"),
+ cl::Hidden, cl::init(false));
+
namespace {
class SanitizerCoverageModule : public ModulePass {
LLVMContext *C;
GlobalVariable *GuardArray;
+ GlobalVariable *EightBitCounterArray;
int CoverageLevel;
};
M.getOrInsertFunction(kSanCovWithCheckName, VoidTy, Int32PtrTy, nullptr));
SanCovIndirCallFunction = checkInterfaceFunction(M.getOrInsertFunction(
kSanCovIndirCallName, VoidTy, IntptrTy, IntptrTy, nullptr));
- SanCovModuleInit = checkInterfaceFunction(
- M.getOrInsertFunction(kSanCovModuleInitName, Type::getVoidTy(*C),
- Int32PtrTy, IntptrTy, Int8PtrTy, nullptr));
+ SanCovModuleInit = checkInterfaceFunction(M.getOrInsertFunction(
+ kSanCovModuleInitName, Type::getVoidTy(*C), Int32PtrTy, IntptrTy,
+ Int8PtrTy, Int8PtrTy, nullptr));
SanCovModuleInit->setLinkage(Function::ExternalLinkage);
// We insert an empty inline asm after cov callbacks to avoid callback merge.
EmptyAsm = InlineAsm::get(FunctionType::get(IRB.getVoidTy(), false),
// At this point we create a dummy array of guards because we don't
// know how many elements we will need.
Type *Int32Ty = IRB.getInt32Ty();
+ Type *Int8Ty = IRB.getInt8Ty();
+
GuardArray =
new GlobalVariable(M, Int32Ty, false, GlobalValue::ExternalLinkage,
nullptr, "__sancov_gen_cov_tmp");
+ if (ClUse8bitCounters)
+ EightBitCounterArray =
+ new GlobalVariable(M, Int8Ty, false, GlobalVariable::ExternalLinkage,
+ nullptr, "__sancov_gen_cov_tmp");
for (auto &F : M)
runOnFunction(F);
M, Int32ArrayNTy, false, GlobalValue::PrivateLinkage,
Constant::getNullValue(Int32ArrayNTy), "__sancov_gen_cov");
+
// Replace the dummy array with the real one.
GuardArray->replaceAllUsesWith(
IRB.CreatePointerCast(RealGuardArray, Int32PtrTy));
GuardArray->eraseFromParent();
+ GlobalVariable *RealEightBitCounterArray;
+ if (ClUse8bitCounters) {
+ // Make sure the array is 16-aligned.
+ static const int kCounterAlignment = 16;
+ Type *Int8ArrayNTy =
+ ArrayType::get(Int8Ty, RoundUpToAlignment(SanCovFunction->getNumUses(),
+ kCounterAlignment));
+ RealEightBitCounterArray = new GlobalVariable(
+ M, Int8ArrayNTy, false, GlobalValue::PrivateLinkage,
+ Constant::getNullValue(Int8ArrayNTy), "__sancov_gen_cov_counter");
+ RealEightBitCounterArray->setAlignment(kCounterAlignment);
+ EightBitCounterArray->replaceAllUsesWith(
+ IRB.CreatePointerCast(RealEightBitCounterArray, Int8PtrTy));
+ EightBitCounterArray->eraseFromParent();
+ }
+
// Create variable for module (compilation unit) name
Constant *ModNameStrConst =
ConstantDataArray::getString(M.getContext(), M.getName(), true);
// Call __sanitizer_cov_module_init
IRB.SetInsertPoint(CtorFunc->getEntryBlock().getTerminator());
- IRB.CreateCall3(SanCovModuleInit,
- IRB.CreatePointerCast(RealGuardArray, Int32PtrTy),
- ConstantInt::get(IntptrTy, SanCovFunction->getNumUses()),
- IRB.CreatePointerCast(ModuleName, Int8PtrTy));
+ IRB.CreateCall4(
+ SanCovModuleInit, IRB.CreatePointerCast(RealGuardArray, Int32PtrTy),
+ ConstantInt::get(IntptrTy, SanCovFunction->getNumUses()),
+ ClUse8bitCounters
+ ? IRB.CreatePointerCast(RealEightBitCounterArray, Int8PtrTy)
+ : Constant::getNullValue(Int8PtrTy),
+ IRB.CreatePointerCast(ModuleName, Int8PtrTy));
return true;
}
IRB.CreateCall(EmptyAsm); // Avoids callback merge.
}
+ if(ClUse8bitCounters) {
+ IRB.SetInsertPoint(IP);
+ Value *P = IRB.CreateAdd(
+ IRB.CreatePointerCast(EightBitCounterArray, IntptrTy),
+ ConstantInt::get(IntptrTy, SanCovFunction->getNumUses() - 1));
+ P = IRB.CreateIntToPtr(P, IRB.getInt8PtrTy());
+ Value *LI = IRB.CreateLoad(P);
+ Value *Inc = IRB.CreateAdd(LI, ConstantInt::get(IRB.getInt8Ty(), 1));
+ IRB.CreateStore(Inc, P);
+ }
+
if (ClExperimentalTracing) {
// Experimental support for tracing.
// Insert a callback with the same guard variable as used for coverage.
; RUN: opt < %s -sancov -sanitizer-coverage-level=2 -sanitizer-coverage-block-threshold=1 -S | FileCheck %s --check-prefix=CHECK_WITH_CHECK
; RUN: opt < %s -sancov -sanitizer-coverage-level=3 -sanitizer-coverage-block-threshold=10 -S | FileCheck %s --check-prefix=CHECK3
; RUN: opt < %s -sancov -sanitizer-coverage-level=4 -S | FileCheck %s --check-prefix=CHECK4
+; RUN: opt < %s -sancov -sanitizer-coverage-level=3 -sanitizer-coverage-8bit-counters=1 -S | FileCheck %s --check-prefix=CHECK-8BIT
-; RUN: opt < %s -sancov -sanitizer-coverage-level=0 -S | FileCheck %s --check-prefix=CHECK0
-; RUN: opt < %s -sancov -sanitizer-coverage-level=1 -S | FileCheck %s --check-prefix=CHECK1
-; RUN: opt < %s -sancov -sanitizer-coverage-level=2 -S | FileCheck %s --check-prefix=CHECK2
; RUN: opt < %s -sancov -sanitizer-coverage-level=2 -sanitizer-coverage-block-threshold=10 \
; RUN: -S | FileCheck %s --check-prefix=CHECK2
; RUN: opt < %s -sancov -sanitizer-coverage-level=2 -sanitizer-coverage-block-threshold=1 \
; CHECK3-NOT: call void @__sanitizer_cov
; CHECK3: ret void
+; test -sanitizer-coverage-8bit-counters=1
+; CHECK-8BIT-LABEL: define void @foo
+
+; CHECK-8BIT: [[V11:%[0-9]*]] = load i8
+; CHECK-8BIT: [[V12:%[0-9]*]] = add i8 [[V11]], 1
+; CHECK-8BIT: store i8 [[V12]]
+; CHECK-8BIT: [[V21:%[0-9]*]] = load i8
+; CHECK-8BIT: [[V22:%[0-9]*]] = add i8 [[V21]], 1
+; CHECK-8BIT: store i8 [[V22]]
+; CHECK-8BIT: [[V31:%[0-9]*]] = load i8
+; CHECK-8BIT: [[V32:%[0-9]*]] = add i8 [[V31]], 1
+; CHECK-8BIT: store i8 [[V32]]
+; CHECK-8BIT: [[V41:%[0-9]*]] = load i8
+; CHECK-8BIT: [[V42:%[0-9]*]] = add i8 [[V41]], 1
+; CHECK-8BIT: store i8 [[V42]]
+
+; CHECK-8BIT: ret void
+
%struct.StructWithVptr = type { i32 (...)** }