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[CSI] Synthesize custom hooks for allocation functions, such as strdu… #275

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[CSI] Synthesize custom hooks for allocation functions, such as strdu… #275

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32 changes: 32 additions & 0 deletions llvm/include/llvm/Transforms/Instrumentation/CSI.h
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Original file line number Diff line number Diff line change
Expand Up @@ -1175,6 +1175,8 @@ struct CSIImpl {
return IRB.getInt64(CsiUnknownId);
}

Value *getCalleeFuncID(const Function *Callee, IRBuilder<> &IRB);

static bool spawnsTapirLoopBody(DetachInst *DI, LoopInfo &LI, TaskInfo &TI);

static BasicBlock::iterator
Expand All @@ -1189,6 +1191,32 @@ struct CSIImpl {
/// Finalize the CSI pass.
void finalizeCsi();

FunctionCallee getHookFunction(StringRef Name, FunctionType *FnTy,
AttributeList AL) {
FunctionCallee Callee = M.getOrInsertFunction(Name, FnTy, AL);
if (Function *Fn = dyn_cast<Function>(Callee.getCallee())) {
Fn->setOnlyAccessesInaccessibleMemOrArgMem();
}
return Callee;
}
template <typename... ArgsTy>
FunctionCallee getHookFunction(StringRef Name, AttributeList AL, Type *RetTy,
ArgsTy... Args) {
FunctionCallee Callee = M.getOrInsertFunction(Name, AL, RetTy, Args...);
if (Function *Fn = dyn_cast<Function>(Callee.getCallee())) {
MemoryEffects ME = MemoryEffects::argMemOnly(ModRefInfo::Ref) |
MemoryEffects::inaccessibleMemOnly(ModRefInfo::ModRef);
Fn->setMemoryEffects(ME);
Fn->setDoesNotThrow();
}
return Callee;
}
template <typename... ArgsTy>
FunctionCallee getHookFunction(StringRef Name, Type *RetTy,
ArgsTy... Args) {
return getHookFunction(Name, AttributeList{}, RetTy, Args...);
}

/// Initialize FunctionCallees for the CSI hooks.
/// @{
void initializeLoadStoreHooks();
Expand All @@ -1202,6 +1230,9 @@ struct CSIImpl {
void initializeAllocFnHooks();
/// @}

FunctionCallee getOrInsertSynthesizedHook(StringRef Name, FunctionType *T,
AttributeList AL = AttributeList());

static StructType *getUnitFedTableType(LLVMContext &C,
PointerType *EntryPointerType);
static Constant *fedTableToUnitFedTable(Module &M,
Expand Down Expand Up @@ -1255,6 +1286,7 @@ struct CSIImpl {
LoopInfo &LI);
void instrumentSync(SyncInst *SI, unsigned SyncRegNum);
void instrumentAlloca(Instruction *I, TaskInfo &TI);
bool instrumentAllocFnLibCall(Instruction *I, const TargetLibraryInfo *TLI);
void instrumentAllocFn(Instruction *I, DominatorTree *DT,
const TargetLibraryInfo *TLI);
void instrumentFree(Instruction *I, const TargetLibraryInfo *TLI);
Expand Down
168 changes: 140 additions & 28 deletions llvm/lib/Transforms/Instrumentation/ComprehensiveStaticInstrumentation.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -746,6 +746,44 @@ void CSIImpl::initializeTapirHooks() {
M.getOrInsertFunction("__csi_after_sync", RetType, IDType, SyncRegType);
}

FunctionCallee CSIImpl::getOrInsertSynthesizedHook(StringRef Name,
FunctionType *T,
AttributeList AL) {
// If no bitcode file has been linked, then we cannot check if it contains a
// particular library hook. Simply return the hook. If the Cilksan library
// doesn't contain that hook, the linker will raise an error.
if (!LinkedBitcode)
return getHookFunction(Name, T, AL);

// Check if the linked bitcode file contains the library hook. If it does,
// return that hook.
if (FunctionsInBitcode.contains(std::string(Name)))
return getHookFunction(Name, T, AL);

// We did not find the library hook in the linked bitcode file. Synthesize a
// default version of the hook that simply calls __csi_default_libhook.
FunctionCallee NewHook = M.getOrInsertFunction(Name, T, AL);
Function *NewHookFn = cast<Function>(NewHook.getCallee());
NewHookFn->setOnlyAccessesInaccessibleMemOrArgMem();
NewHookFn->setDoesNotThrow();
BasicBlock *Entry = BasicBlock::Create(M.getContext(), "entry", NewHookFn);
IRBuilder<> IRB(ReturnInst::Create(M.getContext(), Entry));

// Insert a call to the default library function hook
Type *IDType = IRB.getInt64Ty();
FunctionType *DefaultHookTy =
FunctionType::get(IRB.getVoidTy(),
{/*call_id*/
IDType, /*func_id*/ IDType,
/*MAAP_count*/ IRB.getInt8Ty()},
/*isVarArg*/ false);
FunctionCallee DefaultHook =
M.getOrInsertFunction("__csi_default_libhook", DefaultHookTy);
IRB.CreateCall(DefaultHook, {NewHookFn->getArg(0), NewHookFn->getArg(1),
NewHookFn->getArg(2)});
return NewHook;
}

// Prepare any calls in the CFG for instrumentation, e.g., by making sure any
// call that can throw is modeled with an invoke.
void CSIImpl::setupCalls(Function &F) {
Expand Down Expand Up @@ -1257,16 +1295,40 @@ void CSIImpl::instrumentLoop(Loop &L, TaskInfo &TI, ScalarEvolution *SE) {
}
}

// Helper function to get the ID of a function being called. These IDs are
// stored in separate global variables in the program. This method will create
// a new global variable for the Callee's ID if necessary.
Value *CSIImpl::getCalleeFuncID(const Function *Callee, IRBuilder<> &IRB) {
if (!Callee)
// Unknown targets (i.e., indirect calls) are always unknown.
return IRB.getInt64(CsiCallsiteUnknownTargetId);

std::string GVName =
CsiFuncIdVariablePrefix + Callee->getName().str();
GlobalVariable *FuncIdGV = M.getNamedGlobal(GVName);
Type *FuncIdGVTy = IRB.getInt64Ty();
if (!FuncIdGV) {
FuncIdGV =
dyn_cast<GlobalVariable>(M.getOrInsertGlobal(GVName, FuncIdGVTy));
assert(FuncIdGV);
FuncIdGV->setConstant(false);
if (Options.jitMode && !Callee->empty())
FuncIdGV->setLinkage(Callee->getLinkage());
else
FuncIdGV->setLinkage(GlobalValue::WeakAnyLinkage);
FuncIdGV->setInitializer(IRB.getInt64(CsiCallsiteUnknownTargetId));
}
return IRB.CreateLoad(FuncIdGVTy, FuncIdGV);
}

void CSIImpl::instrumentCallsite(Instruction *I, DominatorTree *DT) {
if (callsPlaceholderFunction(*I))
return;

bool IsInvoke = isa<InvokeInst>(I);
Function *Called = nullptr;
if (CallInst *CI = dyn_cast<CallInst>(I))
Called = CI->getCalledFunction();
else if (InvokeInst *II = dyn_cast<InvokeInst>(I))
Called = II->getCalledFunction();
if (CallBase *CB = dyn_cast<CallBase>(I))
Called = CB->getCalledFunction();

bool ShouldInstrumentBefore = true;
bool ShouldInstrumentAfter = true;
Expand All @@ -1286,25 +1348,7 @@ void CSIImpl::instrumentCallsite(Instruction *I, DominatorTree *DT) {
Value *DefaultID = getDefaultID(IRB);
uint64_t LocalId = CallsiteFED.add(*I, Called ? Called->getName() : "");
Value *CallsiteId = CallsiteFED.localToGlobalId(LocalId, IRB);
Value *FuncId = nullptr;
GlobalVariable *FuncIdGV = nullptr;
if (Called) {
std::string GVName = CsiFuncIdVariablePrefix + Called->getName().str();
Type *FuncIdGVTy = IRB.getInt64Ty();
FuncIdGV = dyn_cast<GlobalVariable>(
M.getOrInsertGlobal(GVName, FuncIdGVTy));
assert(FuncIdGV);
FuncIdGV->setConstant(false);
if (Options.jitMode && !Called->empty())
FuncIdGV->setLinkage(Called->getLinkage());
else
FuncIdGV->setLinkage(GlobalValue::WeakAnyLinkage);
FuncIdGV->setInitializer(IRB.getInt64(CsiCallsiteUnknownTargetId));
FuncId = IRB.CreateLoad(FuncIdGVTy, FuncIdGV);
} else {
// Unknown targets (i.e. indirect calls) are always unknown.
FuncId = IRB.getInt64(CsiCallsiteUnknownTargetId);
}
Value *FuncId = getCalleeFuncID(Called, IRB);
assert(FuncId != NULL);
CsiCallProperty Prop;
Value *DefaultPropVal = Prop.getValue(IRB);
Expand Down Expand Up @@ -1651,14 +1695,79 @@ bool CSIImpl::getAllocFnArgs(const Instruction *I,
return true;
}

bool CSIImpl::instrumentAllocFnLibCall(Instruction *I,
const TargetLibraryInfo *TLI) {
bool IsInvoke = isa<InvokeInst>(I);
CallBase *CB = dyn_cast<CallBase>(I);
if (!CB)
return false;
Function *Called = CB->getCalledFunction();

// Get the CSI IDs for this hook
IRBuilder<> IRB(I);
LLVMContext &Ctx = IRB.getContext();
Value *DefaultID = getDefaultID(IRB);
uint64_t LocalId = AllocFnFED.add(*I);
Value *AllocFnId = AllocFnFED.localToGlobalId(LocalId, IRB);
Value *FuncId = getCalleeFuncID(Called, IRB);
assert(FuncId != NULL);

CsiAllocFnProperty Prop;
Value *DefaultPropVal = Prop.getValue(IRB);
LibFunc AllocLibF;
TLI->getLibFunc(*Called, AllocLibF);
Prop.setAllocFnTy(static_cast<unsigned>(getAllocFnTy(AllocLibF)));
Value *PropVal = Prop.getValue(IRB);
Type *IDType = IRB.getInt64Ty();

// Synthesize the after hook for this function.
SmallVector<Type *, 8> AfterHookParamTys(
{IDType, /*callee func_id*/ IDType, CsiAllocFnProperty::getType(Ctx)});
SmallVector<Value *, 8> AfterHookParamVals({AllocFnId, FuncId, PropVal});
SmallVector<Value *, 8> AfterHookDefaultVals(
{DefaultID, DefaultID, DefaultPropVal});
if (!Called->getReturnType()->isVoidTy()) {
AfterHookParamTys.push_back(Called->getReturnType());
AfterHookParamVals.push_back(CB);
AfterHookDefaultVals.push_back(
Constant::getNullValue(Called->getReturnType()));
}
AfterHookParamTys.append(Called->getFunctionType()->param_begin(),
Called->getFunctionType()->param_end());
AfterHookParamVals.append(CB->arg_begin(), CB->arg_end());
for (Value *Arg : CB->args())
AfterHookDefaultVals.push_back(Constant::getNullValue(Arg->getType()));
FunctionType *AfterHookTy =
FunctionType::get(IRB.getVoidTy(), AfterHookParamTys, Called->isVarArg());
FunctionCallee AfterLibCallHook = getOrInsertSynthesizedHook(
("__csi_alloc_" + Called->getName()).str(), AfterHookTy);

// Insert the hook after the call.
BasicBlock::iterator Iter(I);
if (IsInvoke) {
// There are two "after" positions for invokes: the normal block and the
// exception block.
InvokeInst *II = cast<InvokeInst>(I);
insertHookCallInSuccessorBB(II->getNormalDest(), II->getParent(),
AfterLibCallHook, AfterHookParamVals,
AfterHookDefaultVals);
// Don't insert any instrumentation in the exception block.
} else {
// Simple call instruction; there is only one "after" position.
Iter++;
IRB.SetInsertPoint(&*Iter);
insertHookCall(&*Iter, AfterLibCallHook, AfterHookParamVals);
}

return true;
}

void CSIImpl::instrumentAllocFn(Instruction *I, DominatorTree *DT,
const TargetLibraryInfo *TLI) {
bool IsInvoke = isa<InvokeInst>(I);
Function *Called = nullptr;
if (CallInst *CI = dyn_cast<CallInst>(I))
Called = CI->getCalledFunction();
else if (InvokeInst *II = dyn_cast<InvokeInst>(I))
Called = II->getCalledFunction();
if (CallBase *CB = dyn_cast<CallBase>(I))
Called = CB->getCalledFunction();

assert(Called && "Could not get called function for allocation fn.");

Expand All @@ -1668,7 +1777,10 @@ void CSIImpl::instrumentAllocFn(Instruction *I, DominatorTree *DT,
Value *AllocFnId = AllocFnFED.localToGlobalId(LocalId, IRB);

SmallVector<Value *, 4> AllocFnArgs;
getAllocFnArgs(I, AllocFnArgs, IntptrTy, IRB.getPtrTy(), *TLI);
if (!getAllocFnArgs(I, AllocFnArgs, IntptrTy, IRB.getPtrTy(), *TLI)) {
instrumentAllocFnLibCall(I, TLI);
return;
}
SmallVector<Value *, 4> DefaultAllocFnArgs({
/* Allocated size */ Constant::getNullValue(IntptrTy),
/* Number of elements */ Constant::getNullValue(IntptrTy),
Expand Down
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