// Topologically sorts the basic blocks in the function and writes the ordering
// into the supplied unique vector. The back and incoming edges must have been
// computed first.
void LiveIRVariables::computeTopologicalOrdering(Function &F,
UniqueVector<BasicBlock *> &Ordering) {
assert(IncomingEdges.size() == F.size() &&
"Incoming edges not computed yet!");
SmallVector<unsigned, 256> ProcessedIncomingEdges;
ProcessedIncomingEdges.resize(F.size(), 0);
SmallVector<BasicBlock *, 256> WorkList;
WorkList.push_back(&F.getEntryBlock());
while (!WorkList.empty()) {
BasicBlock *BB = WorkList.back();
WorkList.pop_back();
DEBUG(dbgs() << "Assigning topological order " << Ordering.size());
DEBUG(dbgs() << " to basic block with DFS order ");
DEBUG(dbgs() << (DFSOrdering.idFor(BB) - 1) << "\n");
Ordering.insert(BB);
for (succ_iterator SI = succ_begin(BB),
SE = succ_end(BB); SI != SE; ++SI) {
if (BackEdges.count(std::make_pair(BB, *SI)))
continue;
unsigned DFSID = DFSOrdering.idFor(*SI) - 1;
unsigned ProcessedEdges = ++ProcessedIncomingEdges[DFSID];
if (ProcessedEdges == IncomingEdges[DFSID])
WorkList.push_back(*SI);
}
}
}
// Computes reduced reachability. A basic block B is reduced reachable from a
// basic block A if A has a path to B that passes through no blocks that
// dominate A.
void LiveIRVariables::computeReducedReachability(Function &F) {
// Compute a topological ordering.
UniqueVector<BasicBlock *> TopologicalOrdering;
computeTopologicalOrdering(F, TopologicalOrdering);
// Initialize the reduced reachability matrix.
ReducedReachability.resize(DFSOrdering.size());
// Iterate over the basic blocks in reverse order, building up the reduced
// reachability matrix.
for (unsigned i = TopologicalOrdering.size() - 1; i != (unsigned)-1; --i) {
BasicBlock *BB = TopologicalOrdering[i + 1];
unsigned BBIndex = DFSOrdering.idFor(BB) - 1;
BitVector &BV = ReducedReachability[BBIndex];
BV.resize(DFSOrdering.size());
BV[BBIndex] = true;
for (succ_iterator SI = succ_begin(BB),
SE = succ_end(BB); SI != SE; ++SI) {
if (TopologicalOrdering.idFor(*SI) - 1 < i)
continue; // Ignore back edges.
unsigned SuccessorIndex = DFSOrdering.idFor(*SI) - 1;
BV.set(SuccessorIndex);
BV |= ReducedReachability[SuccessorIndex];
}
}
#ifndef NDEBUG
for (unsigned i = 0, ie = ReducedReachability.size(); i != ie; ++i) {
DEBUG(dbgs() << "Reduced reachability of " << i << ":");
BitVector &BV = ReducedReachability[i];
for (unsigned j = 0, je = BV.size(); j != je; ++j) {
if (BV[j])
DEBUG(dbgs() << " " << j);
}
DEBUG(dbgs() << "\n");
}
#endif
}
bool GCOVProfiler::emitProfileArcs() {
NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
if (!CU_Nodes) return false;
bool Result = false;
bool InsertIndCounterIncrCode = false;
for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
DICompileUnit CU(CU_Nodes->getOperand(i));
DIArray SPs = CU.getSubprograms();
SmallVector<std::pair<GlobalVariable *, MDNode *>, 8> CountersBySP;
for (unsigned i = 0, e = SPs.getNumElements(); i != e; ++i) {
DISubprogram SP(SPs.getElement(i));
if (!SP.Verify()) continue;
Function *F = SP.getFunction();
if (!F) continue;
if (!Result) Result = true;
unsigned Edges = 0;
for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
TerminatorInst *TI = BB->getTerminator();
if (isa<ReturnInst>(TI))
++Edges;
else
Edges += TI->getNumSuccessors();
}
ArrayType *CounterTy =
ArrayType::get(Type::getInt64Ty(*Ctx), Edges);
GlobalVariable *Counters =
new GlobalVariable(*M, CounterTy, false,
GlobalValue::InternalLinkage,
Constant::getNullValue(CounterTy),
"__llvm_gcov_ctr");
CountersBySP.push_back(std::make_pair(Counters, (MDNode*)SP));
UniqueVector<BasicBlock *> ComplexEdgePreds;
UniqueVector<BasicBlock *> ComplexEdgeSuccs;
unsigned Edge = 0;
for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
TerminatorInst *TI = BB->getTerminator();
int Successors = isa<ReturnInst>(TI) ? 1 : TI->getNumSuccessors();
if (Successors) {
IRBuilder<> Builder(TI);
if (Successors == 1) {
Value *Counter = Builder.CreateConstInBoundsGEP2_64(Counters, 0,
Edge);
Value *Count = Builder.CreateLoad(Counter);
Count = Builder.CreateAdd(Count,
ConstantInt::get(Type::getInt64Ty(*Ctx),1));
Builder.CreateStore(Count, Counter);
} else if (BranchInst *BI = dyn_cast<BranchInst>(TI)) {
Value *Sel = Builder.CreateSelect(
BI->getCondition(),
ConstantInt::get(Type::getInt64Ty(*Ctx), Edge),
ConstantInt::get(Type::getInt64Ty(*Ctx), Edge + 1));
SmallVector<Value *, 2> Idx;
Idx.push_back(Constant::getNullValue(Type::getInt64Ty(*Ctx)));
Idx.push_back(Sel);
Value *Counter = Builder.CreateInBoundsGEP(Counters, Idx);
Value *Count = Builder.CreateLoad(Counter);
Count = Builder.CreateAdd(Count,
ConstantInt::get(Type::getInt64Ty(*Ctx),1));
Builder.CreateStore(Count, Counter);
} else {
ComplexEdgePreds.insert(BB);
for (int i = 0; i != Successors; ++i)
ComplexEdgeSuccs.insert(TI->getSuccessor(i));
}
Edge += Successors;
}
}
if (!ComplexEdgePreds.empty()) {
GlobalVariable *EdgeTable =
buildEdgeLookupTable(F, Counters,
ComplexEdgePreds, ComplexEdgeSuccs);
GlobalVariable *EdgeState = getEdgeStateValue();
Type *Int32Ty = Type::getInt32Ty(*Ctx);
for (int i = 0, e = ComplexEdgePreds.size(); i != e; ++i) {
IRBuilder<> Builder(ComplexEdgePreds[i+1]->getTerminator());
Builder.CreateStore(ConstantInt::get(Int32Ty, i), EdgeState);
}
for (int i = 0, e = ComplexEdgeSuccs.size(); i != e; ++i) {
// call runtime to perform increment
BasicBlock::iterator InsertPt =
ComplexEdgeSuccs[i+1]->getFirstInsertionPt();
IRBuilder<> Builder(InsertPt);
Value *CounterPtrArray =
Builder.CreateConstInBoundsGEP2_64(EdgeTable, 0,
i * ComplexEdgePreds.size());
// Build code to increment the counter.
InsertIndCounterIncrCode = true;
Builder.CreateCall2(getIncrementIndirectCounterFunc(),
EdgeState, CounterPtrArray);
}
}
}
insertCounterWriteout(CountersBySP);
insertFlush(CountersBySP);
}
if (InsertIndCounterIncrCode)
insertIndirectCounterIncrement();
return Result;
}
/// IsFunctionMallocLike - A function is malloc-like if it returns either null
/// or a pointer that doesn't alias any other pointer visible to the caller.
bool FunctionAttrs::IsFunctionMallocLike(Function *F,
SmallPtrSet<Function*, 8> &SCCNodes) const {
UniqueVector<Value *> FlowsToReturn;
for (Function::iterator I = F->begin(), E = F->end(); I != E; ++I)
if (ReturnInst *Ret = dyn_cast<ReturnInst>(I->getTerminator()))
FlowsToReturn.insert(Ret->getReturnValue());
for (unsigned i = 0; i != FlowsToReturn.size(); ++i) {
Value *RetVal = FlowsToReturn[i+1]; // UniqueVector[0] is reserved.
if (Constant *C = dyn_cast<Constant>(RetVal)) {
if (!C->isNullValue() && !isa<UndefValue>(C))
return false;
continue;
}
if (isa<Argument>(RetVal))
return false;
if (Instruction *RVI = dyn_cast<Instruction>(RetVal))
switch (RVI->getOpcode()) {
// Extend the analysis by looking upwards.
case Instruction::BitCast:
case Instruction::GetElementPtr:
FlowsToReturn.insert(RVI->getOperand(0));
continue;
case Instruction::Select: {
SelectInst *SI = cast<SelectInst>(RVI);
FlowsToReturn.insert(SI->getTrueValue());
FlowsToReturn.insert(SI->getFalseValue());
continue;
}
case Instruction::PHI: {
PHINode *PN = cast<PHINode>(RVI);
for (int i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
FlowsToReturn.insert(PN->getIncomingValue(i));
continue;
}
// Check whether the pointer came from an allocation.
case Instruction::Alloca:
break;
case Instruction::Call:
case Instruction::Invoke: {
CallSite CS(RVI);
if (CS.paramHasNoAliasAttr(0))
break;
if (CS.getCalledFunction() &&
SCCNodes.count(CS.getCalledFunction()))
break;
} // fall-through
default:
return false; // Did not come from an allocation.
}
if (PointerMayBeCaptured(RetVal, false, /*StoreCaptures=*/false))
return false;
}
return true;
}
bool GCOVProfiler::emitProfileArcs() {
NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
if (!CU_Nodes) return false;
bool Result = false;
bool InsertIndCounterIncrCode = false;
for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
auto *CU = cast<DICompileUnit>(CU_Nodes->getOperand(i));
SmallVector<std::pair<GlobalVariable *, MDNode *>, 8> CountersBySP;
for (auto *SP : CU->getSubprograms()) {
Function *F = FnMap[SP];
if (!F) continue;
if (!functionHasLines(F)) continue;
if (!Result) Result = true;
unsigned Edges = 0;
for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
TerminatorInst *TI = BB->getTerminator();
if (isa<ReturnInst>(TI))
++Edges;
else
Edges += TI->getNumSuccessors();
}
ArrayType *CounterTy =
ArrayType::get(Type::getInt64Ty(*Ctx), Edges);
GlobalVariable *Counters =
new GlobalVariable(*M, CounterTy, false,
GlobalValue::InternalLinkage,
Constant::getNullValue(CounterTy),
"__llvm_gcov_ctr");
CountersBySP.push_back(std::make_pair(Counters, SP));
UniqueVector<BasicBlock *> ComplexEdgePreds;
UniqueVector<BasicBlock *> ComplexEdgeSuccs;
unsigned Edge = 0;
for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
TerminatorInst *TI = BB->getTerminator();
int Successors = isa<ReturnInst>(TI) ? 1 : TI->getNumSuccessors();
if (Successors) {
if (Successors == 1) {
IRBuilder<> Builder(&*BB->getFirstInsertionPt());
Value *Counter = Builder.CreateConstInBoundsGEP2_64(Counters, 0,
Edge);
Value *Count = Builder.CreateLoad(Counter);
Count = Builder.CreateAdd(Count, Builder.getInt64(1));
Builder.CreateStore(Count, Counter);
} else if (BranchInst *BI = dyn_cast<BranchInst>(TI)) {
IRBuilder<> Builder(BI);
Value *Sel = Builder.CreateSelect(BI->getCondition(),
Builder.getInt64(Edge),
Builder.getInt64(Edge + 1));
SmallVector<Value *, 2> Idx;
Idx.push_back(Builder.getInt64(0));
Idx.push_back(Sel);
Value *Counter = Builder.CreateInBoundsGEP(Counters->getValueType(),
Counters, Idx);
Value *Count = Builder.CreateLoad(Counter);
Count = Builder.CreateAdd(Count, Builder.getInt64(1));
Builder.CreateStore(Count, Counter);
} else {
ComplexEdgePreds.insert(&*BB);
for (int i = 0; i != Successors; ++i)
ComplexEdgeSuccs.insert(TI->getSuccessor(i));
}
Edge += Successors;
}
}
if (!ComplexEdgePreds.empty()) {
GlobalVariable *EdgeTable =
buildEdgeLookupTable(F, Counters,
ComplexEdgePreds, ComplexEdgeSuccs);
GlobalVariable *EdgeState = getEdgeStateValue();
for (int i = 0, e = ComplexEdgePreds.size(); i != e; ++i) {
IRBuilder<> Builder(&*ComplexEdgePreds[i + 1]->getFirstInsertionPt());
Builder.CreateStore(Builder.getInt32(i), EdgeState);
}
for (int i = 0, e = ComplexEdgeSuccs.size(); i != e; ++i) {
// Call runtime to perform increment.
IRBuilder<> Builder(&*ComplexEdgeSuccs[i + 1]->getFirstInsertionPt());
Value *CounterPtrArray =
Builder.CreateConstInBoundsGEP2_64(EdgeTable, 0,
i * ComplexEdgePreds.size());
// Build code to increment the counter.
InsertIndCounterIncrCode = true;
Builder.CreateCall(getIncrementIndirectCounterFunc(),
{EdgeState, CounterPtrArray});
}
}
}
Function *WriteoutF = insertCounterWriteout(CountersBySP);
Function *FlushF = insertFlush(CountersBySP);
// Create a small bit of code that registers the "__llvm_gcov_writeout" to
// be executed at exit and the "__llvm_gcov_flush" function to be executed
// when "__gcov_flush" is called.
FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
Function *F = Function::Create(FTy, GlobalValue::InternalLinkage,
"__llvm_gcov_init", M);
F->setUnnamedAddr(true);
F->setLinkage(GlobalValue::InternalLinkage);
F->addFnAttr(Attribute::NoInline);
if (Options.NoRedZone)
F->addFnAttr(Attribute::NoRedZone);
BasicBlock *BB = BasicBlock::Create(*Ctx, "entry", F);
IRBuilder<> Builder(BB);
FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
Type *Params[] = {
PointerType::get(FTy, 0),
PointerType::get(FTy, 0)
};
FTy = FunctionType::get(Builder.getVoidTy(), Params, false);
// Initialize the environment and register the local writeout and flush
// functions.
Constant *GCOVInit = M->getOrInsertFunction("llvm_gcov_init", FTy);
Builder.CreateCall(GCOVInit, {WriteoutF, FlushF});
Builder.CreateRetVoid();
appendToGlobalCtors(*M, F, 0);
}
if (InsertIndCounterIncrCode)
insertIndirectCounterIncrement();
return Result;
}