void InvalidateWithChildren(Block *New) { // TODO: rename New
BlockList ToInvalidate; // Being in the list means you need to be invalidated
ToInvalidate.push_back(New);
while (ToInvalidate.size() > 0) {
Block *Invalidatee = ToInvalidate.front();
ToInvalidate.pop_front();
Block *Owner = Ownership[Invalidatee];
if (IndependentGroups.find(Owner) != IndependentGroups.end()) { // Owner may have been invalidated, do not add to IndependentGroups!
IndependentGroups[Owner].erase(Invalidatee);
}
if (Ownership[Invalidatee]) { // may have been seen before and invalidated already
Ownership[Invalidatee] = NULL;
for (BlockBranchMap::iterator iter = Invalidatee->BranchesOut.begin(); iter != Invalidatee->BranchesOut.end(); iter++) {
Block *Target = iter->first;
BlockBlockMap::iterator Known = Ownership.find(Target);
if (Known != Ownership.end()) {
Block *TargetOwner = Known->second;
if (TargetOwner) {
ToInvalidate.push_back(Target);
}
}
}
}
}
}
void FindLive(Block *Root) {
BlockList ToInvestigate;
ToInvestigate.push_back(Root);
while (ToInvestigate.size() > 0) {
Block *Curr = ToInvestigate.front();
ToInvestigate.pop_front();
if (Live.find(Curr) != Live.end()) continue;
Live.insert(Curr);
for (BlockBranchMap::iterator iter = Curr->BranchesOut.begin(); iter != Curr->BranchesOut.end(); iter++) {
ToInvestigate.push_back(iter->first);
}
}
}
// For each entry, find the independent group reachable by it. The independent group is
// the entry itself, plus all the blocks it can reach that cannot be directly reached by another entry. Note that we
// ignore directly reaching the entry itself by another entry.
void FindIndependentGroups(BlockSet &Blocks, BlockSet &Entries, BlockBlockSetMap& IndependentGroups) {
typedef std::map<Block*, Block*> BlockBlockMap;
struct HelperClass {
BlockBlockSetMap& IndependentGroups;
BlockBlockMap Ownership; // For each block, which entry it belongs to. We have reached it from there.
HelperClass(BlockBlockSetMap& IndependentGroupsInit) : IndependentGroups(IndependentGroupsInit) {}
void InvalidateWithChildren(Block *New) { // TODO: rename New
BlockList ToInvalidate; // Being in the list means you need to be invalidated
ToInvalidate.push_back(New);
while (ToInvalidate.size() > 0) {
Block *Invalidatee = ToInvalidate.front();
ToInvalidate.pop_front();
Block *Owner = Ownership[Invalidatee];
if (IndependentGroups.find(Owner) != IndependentGroups.end()) { // Owner may have been invalidated, do not add to IndependentGroups!
IndependentGroups[Owner].erase(Invalidatee);
}
if (Ownership[Invalidatee]) { // may have been seen before and invalidated already
Ownership[Invalidatee] = NULL;
for (BlockBranchMap::iterator iter = Invalidatee->BranchesOut.begin(); iter != Invalidatee->BranchesOut.end(); iter++) {
Block *Target = iter->first;
BlockBlockMap::iterator Known = Ownership.find(Target);
if (Known != Ownership.end()) {
Block *TargetOwner = Known->second;
if (TargetOwner) {
ToInvalidate.push_back(Target);
}
}
}
}
}
}
};
HelperClass Helper(IndependentGroups);
// We flow out from each of the entries, simultaneously.
// When we reach a new block, we add it as belonging to the one we got to it from.
// If we reach a new block that is already marked as belonging to someone, it is reachable by
// two entries and is not valid for any of them. Remove it and all it can reach that have been
// visited.
BlockList Queue; // Being in the queue means we just added this item, and we need to add its children
for (BlockSet::iterator iter = Entries.begin(); iter != Entries.end(); iter++) {
Block *Entry = *iter;
Helper.Ownership[Entry] = Entry;
IndependentGroups[Entry].insert(Entry);
Queue.push_back(Entry);
}
while (Queue.size() > 0) {
Block *Curr = Queue.front();
Queue.pop_front();
Block *Owner = Helper.Ownership[Curr]; // Curr must be in the ownership map if we are in the queue
if (!Owner) continue; // we have been invalidated meanwhile after being reached from two entries
// Add all children
for (BlockBranchMap::iterator iter = Curr->BranchesOut.begin(); iter != Curr->BranchesOut.end(); iter++) {
Block *New = iter->first;
BlockBlockMap::iterator Known = Helper.Ownership.find(New);
if (Known == Helper.Ownership.end()) {
// New node. Add it, and put it in the queue
Helper.Ownership[New] = Owner;
IndependentGroups[Owner].insert(New);
Queue.push_back(New);
continue;
}
Block *NewOwner = Known->second;
if (!NewOwner) continue; // We reached an invalidated node
if (NewOwner != Owner) {
// Invalidate this and all reachable that we have seen - we reached this from two locations
Helper.InvalidateWithChildren(New);
}
// otherwise, we have the same owner, so do nothing
}
}
// Having processed all the interesting blocks, we remain with just one potential issue:
// If a->b, and a was invalidated, but then b was later reached by someone else, we must
// invalidate b. To check for this, we go over all elements in the independent groups,
// if an element has a parent which does *not* have the same owner, we must remove it
// and all its children.
for (BlockSet::iterator iter = Entries.begin(); iter != Entries.end(); iter++) {
BlockSet &CurrGroup = IndependentGroups[*iter];
BlockList ToInvalidate;
for (BlockSet::iterator iter = CurrGroup.begin(); iter != CurrGroup.end(); iter++) {
Block *Child = *iter;
for (BlockBranchMap::iterator iter = Child->BranchesIn.begin(); iter != Child->BranchesIn.end(); iter++) {
Block *Parent = iter->first;
if (Helper.Ownership[Parent] != Helper.Ownership[Child]) {
ToInvalidate.push_back(Child);
}
}
}
while (ToInvalidate.size() > 0) {
Block *Invalidatee = ToInvalidate.front();
ToInvalidate.pop_front();
Helper.InvalidateWithChildren(Invalidatee);
}
}
// Remove empty groups
for (BlockSet::iterator iter = Entries.begin(); iter != Entries.end(); iter++) {
if (IndependentGroups[*iter].size() == 0) {
IndependentGroups.erase(*iter);
}
}
#if DEBUG
PrintDebug("Investigated independent groups:\n");
for (BlockBlockSetMap::iterator iter = IndependentGroups.begin(); iter != IndependentGroups.end(); iter++) {
DebugDump(iter->second, " group: ");
}
#endif
}