static void addInstructionToGraph(CFLAliasAnalysis &Analysis, Instruction &Inst,
SmallVectorImpl<Value *> &ReturnedValues,
NodeMapT &Map, GraphT &Graph) {
const auto findOrInsertNode = [&Map, &Graph](Value *Val) {
auto Pair = Map.insert(std::make_pair(Val, GraphT::Node()));
auto &Iter = Pair.first;
if (Pair.second) {
auto NewNode = Graph.addNode();
Iter->second = NewNode;
}
return Iter->second;
};
// We don't want the edges of most "return" instructions, but we *do* want
// to know what can be returned.
if (isa<ReturnInst>(&Inst))
ReturnedValues.push_back(&Inst);
if (!hasUsefulEdges(&Inst))
return;
SmallVector<Edge, 8> Edges;
argsToEdges(Analysis, &Inst, Edges);
// In the case of an unused alloca (or similar), edges may be empty. Note
// that it exists so we can potentially answer NoAlias.
if (Edges.empty()) {
auto MaybeVal = getTargetValue(&Inst);
assert(MaybeVal.hasValue());
auto *Target = *MaybeVal;
findOrInsertNode(Target);
return;
}
const auto addEdgeToGraph = [&Graph, &findOrInsertNode](const Edge &E) {
auto To = findOrInsertNode(E.To);
auto From = findOrInsertNode(E.From);
auto FlippedWeight = flipWeight(E.Weight);
auto Attrs = E.AdditionalAttrs;
Graph.addEdge(From, To, std::make_pair(E.Weight, Attrs),
std::make_pair(FlippedWeight, Attrs));
};
SmallVector<ConstantExpr *, 4> ConstantExprs;
for (const Edge &E : Edges) {
addEdgeToGraph(E);
if (auto *Constexpr = dyn_cast<ConstantExpr>(E.To))
ConstantExprs.push_back(Constexpr);
if (auto *Constexpr = dyn_cast<ConstantExpr>(E.From))
ConstantExprs.push_back(Constexpr);
}
for (ConstantExpr *CE : ConstantExprs) {
Edges.clear();
constexprToEdges(Analysis, *CE, Edges);
std::for_each(Edges.begin(), Edges.end(), addEdgeToGraph);
}
}
// Aside: We may remove graph construction entirely, because it doesn't really
// buy us much that we don't already have. I'd like to add interprocedural
// analysis prior to this however, in case that somehow requires the graph
// produced by this for efficient execution
static void buildGraphFrom(CFLAliasAnalysis &Analysis, Function *Fn,
SmallVectorImpl<Value *> &ReturnedValues,
NodeMapT &Map, GraphT &Graph) {
const auto findOrInsertNode = [&Map, &Graph](Value *Val) {
auto Pair = Map.insert(std::make_pair(Val, GraphT::Node()));
auto &Iter = Pair.first;
if (Pair.second) {
auto NewNode = Graph.addNode();
Iter->second = NewNode;
}
return Iter->second;
};
SmallVector<Edge, 8> Edges;
for (auto &Bb : Fn->getBasicBlockList()) {
for (auto &Inst : Bb.getInstList()) {
// We don't want the edges of most "return" instructions, but we *do* want
// to know what can be returned.
if (auto *Ret = dyn_cast<ReturnInst>(&Inst))
ReturnedValues.push_back(Ret);
if (!hasUsefulEdges(&Inst))
continue;
Edges.clear();
argsToEdges(Analysis, &Inst, Edges);
// In the case of an unused alloca (or similar), edges may be empty. Note
// that it exists so we can potentially answer NoAlias.
if (Edges.empty()) {
auto MaybeVal = getTargetValue(&Inst);
assert(MaybeVal.hasValue());
auto *Target = *MaybeVal;
findOrInsertNode(Target);
continue;
}
for (const Edge &E : Edges) {
auto To = findOrInsertNode(E.To);
auto From = findOrInsertNode(E.From);
auto FlippedWeight = flipWeight(E.Weight);
auto Attrs = E.AdditionalAttrs;
Graph.addEdge(From, To, std::make_pair(E.Weight, Attrs),
std::make_pair(FlippedWeight, Attrs));
}
}
}
}
static FunctionInfo buildSetsFrom(CFLAliasAnalysis &Analysis, Function *Fn) {
NodeMapT Map;
GraphT Graph;
SmallVector<Value *, 4> ReturnedValues;
buildGraphFrom(Analysis, Fn, ReturnedValues, Map, Graph);
DenseMap<GraphT::Node, Value *> NodeValueMap;
NodeValueMap.resize(Map.size());
for (const auto &Pair : Map)
NodeValueMap.insert(std::make_pair(Pair.second, Pair.first));
const auto findValueOrDie = [&NodeValueMap](GraphT::Node Node) {
auto ValIter = NodeValueMap.find(Node);
assert(ValIter != NodeValueMap.end());
return ValIter->second;
};
StratifiedSetsBuilder<Value *> Builder;
SmallVector<GraphT::Node, 16> Worklist;
for (auto &Pair : Map) {
Worklist.clear();
auto *Value = Pair.first;
Builder.add(Value);
auto InitialNode = Pair.second;
Worklist.push_back(InitialNode);
while (!Worklist.empty()) {
auto Node = Worklist.pop_back_val();
auto *CurValue = findValueOrDie(Node);
if (isa<Constant>(CurValue) && !isa<GlobalValue>(CurValue))
continue;
for (const auto &EdgeTuple : Graph.edgesFor(Node)) {
auto Weight = std::get<0>(EdgeTuple);
auto Label = Weight.first;
auto &OtherNode = std::get<1>(EdgeTuple);
auto *OtherValue = findValueOrDie(OtherNode);
if (isa<Constant>(OtherValue) && !isa<GlobalValue>(OtherValue))
continue;
bool Added;
switch (directionOfEdgeType(Label)) {
case Level::Above:
Added = Builder.addAbove(CurValue, OtherValue);
break;
case Level::Below:
Added = Builder.addBelow(CurValue, OtherValue);
break;
case Level::Same:
Added = Builder.addWith(CurValue, OtherValue);
break;
}
if (Added) {
auto Aliasing = Weight.second;
if (auto MaybeCurIndex = valueToAttrIndex(CurValue))
Aliasing.set(*MaybeCurIndex);
if (auto MaybeOtherIndex = valueToAttrIndex(OtherValue))
Aliasing.set(*MaybeOtherIndex);
Builder.noteAttributes(CurValue, Aliasing);
Builder.noteAttributes(OtherValue, Aliasing);
Worklist.push_back(OtherNode);
}
}
}
}
// There are times when we end up with parameters not in our graph (i.e. if
// it's only used as the condition of a branch). Other bits of code depend on
// things that were present during construction being present in the graph.
// So, we add all present arguments here.
for (auto &Arg : Fn->args()) {
Builder.add(&Arg);
}
return FunctionInfo(Builder.build(), std::move(ReturnedValues));
}
