// FIXME: This code is stolen from CallGraph::addToCallGraph(Function *F), which
// happens to be private. It is better for this functionality exposed by the
// CallGraph.
static void buildCGN(CallGraph &CG, CallGraphNode *Node) {
Function *F = Node->getFunction();
// Look for calls by this function.
for (Instruction &I : instructions(F))
if (CallSite CS = CallSite(cast<Value>(&I))) {
const Function *Callee = CS.getCalledFunction();
if (!Callee || !Intrinsic::isLeaf(Callee->getIntrinsicID()))
// Indirect calls of intrinsics are not allowed so no need to check.
// We can be more precise here by using TargetArg returned by
// Intrinsic::isLeaf.
Node->addCalledFunction(CS, CG.getCallsExternalNode());
else if (!Callee->isIntrinsic())
Node->addCalledFunction(CS, CG.getOrInsertFunction(Callee));
}
}
// Rebuild CGN after we extracted parts of the code from ParentFunc into
// NewFuncs. Builds CGNs for the NewFuncs and adds them to the current SCC.
void coro::updateCallGraph(Function &ParentFunc, ArrayRef<Function *> NewFuncs,
CallGraph &CG, CallGraphSCC &SCC) {
// Rebuild CGN from scratch for the ParentFunc
auto *ParentNode = CG[&ParentFunc];
ParentNode->removeAllCalledFunctions();
buildCGN(CG, ParentNode);
SmallVector<CallGraphNode *, 8> Nodes(SCC.begin(), SCC.end());
for (Function *F : NewFuncs) {
CallGraphNode *Callee = CG.getOrInsertFunction(F);
Nodes.push_back(Callee);
buildCGN(CG, Callee);
}
SCC.initialize(Nodes);
}
// Make sure that there is a devirtualization trigger function that CoroSplit
// pass uses the force restart CGSCC pipeline. If devirt trigger function is not
// found, we will create one and add it to the current SCC.
static void createDevirtTriggerFunc(CallGraph &CG, CallGraphSCC &SCC) {
Module &M = CG.getModule();
if (M.getFunction(CORO_DEVIRT_TRIGGER_FN))
return;
LLVMContext &C = M.getContext();
auto *FnTy = FunctionType::get(Type::getVoidTy(C), Type::getInt8PtrTy(C),
/*IsVarArgs=*/false);
Function *DevirtFn =
Function::Create(FnTy, GlobalValue::LinkageTypes::PrivateLinkage,
CORO_DEVIRT_TRIGGER_FN, &M);
DevirtFn->addFnAttr(Attribute::AlwaysInline);
auto *Entry = BasicBlock::Create(C, "entry", DevirtFn);
ReturnInst::Create(C, Entry);
auto *Node = CG.getOrInsertFunction(DevirtFn);
SmallVector<CallGraphNode *, 8> Nodes(SCC.begin(), SCC.end());
Nodes.push_back(Node);
SCC.initialize(Nodes);
}