+
+ /// removeLoop - This removes the specified top-level loop from this loop info
+ /// object. The loop is not deleted, as it will presumably be inserted into
+ /// another loop.
+ LoopBase<BlockT> *removeLoop(iterator I) {
+ assert(I != end() && "Cannot remove end iterator!");
+ LoopBase<BlockT> *L = *I;
+ assert(L->getParentLoop() == 0 && "Not a top-level loop!");
+ TopLevelLoops.erase(TopLevelLoops.begin() + (I-begin()));
+ return L;
+ }
+
+ /// changeLoopFor - Change the top-level loop that contains BB to the
+ /// specified loop. This should be used by transformations that restructure
+ /// the loop hierarchy tree.
+ void changeLoopFor(BlockT *BB, LoopBase<BlockT> *L) {
+ LoopBase<BlockT> *&OldLoop = BBMap[BB];
+ assert(OldLoop && "Block not in a loop yet!");
+ OldLoop = L;
+ }
+
+ /// changeTopLevelLoop - Replace the specified loop in the top-level loops
+ /// list with the indicated loop.
+ void changeTopLevelLoop(LoopBase<BlockT> *OldLoop,
+ LoopBase<BlockT> *NewLoop) {
+ typename std::vector<LoopBase<BlockT>*>::iterator I =
+ std::find(TopLevelLoops.begin(), TopLevelLoops.end(), OldLoop);
+ assert(I != TopLevelLoops.end() && "Old loop not at top level!");
+ *I = NewLoop;
+ assert(NewLoop->ParentLoop == 0 && OldLoop->ParentLoop == 0 &&
+ "Loops already embedded into a subloop!");
+ }
+
+ /// addTopLevelLoop - This adds the specified loop to the collection of
+ /// top-level loops.
+ void addTopLevelLoop(LoopBase<BlockT> *New) {
+ assert(New->getParentLoop() == 0 && "Loop already in subloop!");
+ TopLevelLoops.push_back(New);
+ }
+
+ /// removeBlock - This method completely removes BB from all data structures,
+ /// including all of the Loop objects it is nested in and our mapping from
+ /// BasicBlocks to loops.
+ void removeBlock(BlockT *BB) {
+ typename std::map<BlockT *, LoopBase<BlockT>*>::iterator I = BBMap.find(BB);
+ if (I != BBMap.end()) {
+ for (Loop *L = I->second; L; L = L->getParentLoop())
+ L->removeBlockFromLoop(BB);
+
+ BBMap.erase(I);
+ }
+ }
+
+ // Internals
+
+ static bool isNotAlreadyContainedIn(Loop *SubLoop, Loop *ParentLoop) {
+ if (SubLoop == 0) return true;
+ if (SubLoop == ParentLoop) return false;
+ return isNotAlreadyContainedIn(SubLoop->getParentLoop(), ParentLoop);
+ }
+
+ void Calculate(DominatorTree &DT) {
+ BlockT *RootNode = DT.getRootNode()->getBlock();
+
+ for (df_iterator<BlockT*> NI = df_begin(RootNode),
+ NE = df_end(RootNode); NI != NE; ++NI)
+ if (LoopBase<BlockT> *L = ConsiderForLoop(*NI, DT))
+ TopLevelLoops.push_back(L);
+ }
+
+ LoopBase<BlockT> *ConsiderForLoop(BlockT *BB, DominatorTree &DT) {
+ if (BBMap.find(BB) != BBMap.end()) return 0;// Haven't processed this node?
+
+ std::vector<BlockT *> TodoStack;
+
+ // Scan the predecessors of BB, checking to see if BB dominates any of
+ // them. This identifies backedges which target this node...
+ for (pred_iterator I = pred_begin(BB), E = pred_end(BB); I != E; ++I)
+ if (DT.dominates(BB, *I)) // If BB dominates it's predecessor...
+ TodoStack.push_back(*I);
+
+ if (TodoStack.empty()) return 0; // No backedges to this block...
+
+ // Create a new loop to represent this basic block...
+ LoopBase<BlockT> *L = new LoopBase<BlockT>(BB);
+ BBMap[BB] = L;
+
+ BlockT *EntryBlock = &BB->getParent()->getEntryBlock();
+
+ while (!TodoStack.empty()) { // Process all the nodes in the loop
+ BlockT *X = TodoStack.back();
+ TodoStack.pop_back();
+
+ if (!L->contains(X) && // As of yet unprocessed??
+ DT.dominates(EntryBlock, X)) { // X is reachable from entry block?
+ // Check to see if this block already belongs to a loop. If this occurs
+ // then we have a case where a loop that is supposed to be a child of the
+ // current loop was processed before the current loop. When this occurs,
+ // this child loop gets added to a part of the current loop, making it a
+ // sibling to the current loop. We have to reparent this loop.
+ if (LoopBase<BlockT> *SubLoop =
+ const_cast<LoopBase<BlockT>*>(getLoopFor(X)))
+ if (SubLoop->getHeader() == X && isNotAlreadyContainedIn(SubLoop, L)) {
+ // Remove the subloop from it's current parent...
+ assert(SubLoop->ParentLoop && SubLoop->ParentLoop != L);
+ LoopBase<BlockT> *SLP = SubLoop->ParentLoop; // SubLoopParent
+ typename std::vector<LoopBase<BlockT>*>::iterator I =
+ std::find(SLP->SubLoops.begin(), SLP->SubLoops.end(), SubLoop);
+ assert(I != SLP->SubLoops.end() && "SubLoop not a child of parent?");
+ SLP->SubLoops.erase(I); // Remove from parent...
+
+ // Add the subloop to THIS loop...
+ SubLoop->ParentLoop = L;
+ L->SubLoops.push_back(SubLoop);
+ }
+
+ // Normal case, add the block to our loop...
+ L->Blocks.push_back(X);
+
+ // Add all of the predecessors of X to the end of the work stack...
+ TodoStack.insert(TodoStack.end(), pred_begin(X), pred_end(X));
+ }
+ }
+
+ // If there are any loops nested within this loop, create them now!
+ for (typename std::vector<BlockT*>::iterator I = L->Blocks.begin(),
+ E = L->Blocks.end(); I != E; ++I)
+ if (LoopBase<BlockT> *NewLoop = ConsiderForLoop(*I, DT)) {
+ L->SubLoops.push_back(NewLoop);
+ NewLoop->ParentLoop = L;
+ }
+
+ // Add the basic blocks that comprise this loop to the BBMap so that this
+ // loop can be found for them.
+ //
+ for (typename std::vector<BlockT*>::iterator I = L->Blocks.begin(),
+ E = L->Blocks.end(); I != E; ++I) {
+ typename std::map<BlockT*, LoopBase<BlockT>*>::iterator BBMI =
+ BBMap.lower_bound(*I);
+ if (BBMI == BBMap.end() || BBMI->first != *I) // Not in map yet...
+ BBMap.insert(BBMI, std::make_pair(*I, L)); // Must be at this level
+ }
+
+ // Now that we have a list of all of the child loops of this loop, check to
+ // see if any of them should actually be nested inside of each other. We can
+ // accidentally pull loops our of their parents, so we must make sure to
+ // organize the loop nests correctly now.
+ {
+ std::map<BlockT*, LoopBase<BlockT>*> ContainingLoops;
+ for (unsigned i = 0; i != L->SubLoops.size(); ++i) {
+ LoopBase<BlockT> *Child = L->SubLoops[i];
+ assert(Child->getParentLoop() == L && "Not proper child loop?");
+
+ if (LoopBase<BlockT> *ContainingLoop =
+ ContainingLoops[Child->getHeader()]) {
+ // If there is already a loop which contains this loop, move this loop
+ // into the containing loop.
+ MoveSiblingLoopInto(Child, ContainingLoop);
+ --i; // The loop got removed from the SubLoops list.
+ } else {
+ // This is currently considered to be a top-level loop. Check to see if
+ // any of the contained blocks are loop headers for subloops we have
+ // already processed.
+ for (unsigned b = 0, e = Child->Blocks.size(); b != e; ++b) {
+ LoopBase<BlockT> *&BlockLoop = ContainingLoops[Child->Blocks[b]];
+ if (BlockLoop == 0) { // Child block not processed yet...
+ BlockLoop = Child;
+ } else if (BlockLoop != Child) {
+ LoopBase<BlockT> *SubLoop = BlockLoop;
+ // Reparent all of the blocks which used to belong to BlockLoops
+ for (unsigned j = 0, e = SubLoop->Blocks.size(); j != e; ++j)
+ ContainingLoops[SubLoop->Blocks[j]] = Child;
+
+ // There is already a loop which contains this block, that means
+ // that we should reparent the loop which the block is currently
+ // considered to belong to to be a child of this loop.
+ MoveSiblingLoopInto(SubLoop, Child);
+ --i; // We just shrunk the SubLoops list.
+ }
+ }
+ }
+ }
+ }
+
+ return L;
+ }
+
+ /// MoveSiblingLoopInto - This method moves the NewChild loop to live inside of
+ /// the NewParent Loop, instead of being a sibling of it.
+ void MoveSiblingLoopInto(LoopBase<BlockT> *NewChild,
+ LoopBase<BlockT> *NewParent) {
+ LoopBase<BlockT> *OldParent = NewChild->getParentLoop();
+ assert(OldParent && OldParent == NewParent->getParentLoop() &&
+ NewChild != NewParent && "Not sibling loops!");
+
+ // Remove NewChild from being a child of OldParent
+ typename std::vector<LoopBase<BlockT>*>::iterator I =
+ std::find(OldParent->SubLoops.begin(), OldParent->SubLoops.end(), NewChild);
+ assert(I != OldParent->SubLoops.end() && "Parent fields incorrect??");
+ OldParent->SubLoops.erase(I); // Remove from parent's subloops list
+ NewChild->ParentLoop = 0;
+
+ InsertLoopInto(NewChild, NewParent);
+ }
+
+ /// InsertLoopInto - This inserts loop L into the specified parent loop. If the
+ /// parent loop contains a loop which should contain L, the loop gets inserted
+ /// into L instead.
+ void InsertLoopInto(LoopBase<BlockT> *L, LoopBase<BlockT> *Parent) {
+ BlockT *LHeader = L->getHeader();
+ assert(Parent->contains(LHeader) && "This loop should not be inserted here!");
+
+ // Check to see if it belongs in a child loop...
+ for (unsigned i = 0, e = Parent->SubLoops.size(); i != e; ++i)
+ if (Parent->SubLoops[i]->contains(LHeader)) {
+ InsertLoopInto(L, Parent->SubLoops[i]);
+ return;
+ }
+
+ // If not, insert it here!
+ Parent->SubLoops.push_back(L);
+ L->ParentLoop = Parent;
+ }
+
+ // Debugging
+
+ void print(std::ostream &OS, const Module* ) const {
+ for (unsigned i = 0; i < TopLevelLoops.size(); ++i)
+ TopLevelLoops[i]->print(OS);
+ #if 0
+ for (std::map<BasicBlock*, Loop*>::const_iterator I = BBMap.begin(),
+ E = BBMap.end(); I != E; ++I)
+ OS << "BB '" << I->first->getName() << "' level = "
+ << I->second->getLoopDepth() << "\n";
+ #endif
+ }
+};
+
+class LoopInfo : public FunctionPass {
+ LoopInfoBase<BasicBlock>* LI;
+ friend class LoopBase<BasicBlock>;
+
+ LoopInfoBase<BasicBlock>& getBase() { return *LI; }
+public:
+ static char ID; // Pass identification, replacement for typeid
+
+ LoopInfo() : FunctionPass(intptr_t(&ID)) {
+ LI = new LoopInfoBase<BasicBlock>();
+ }
+
+ ~LoopInfo() { LI->releaseMemory(); }
+
+ /// iterator/begin/end - The interface to the top-level loops in the current
+ /// function.
+ ///
+ typedef std::vector<Loop*>::const_iterator iterator;
+ inline iterator begin() const { return LI->begin(); }
+ inline iterator end() const { return LI->end(); }
+
+ /// getLoopFor - Return the inner most loop that BB lives in. If a basic
+ /// block is in no loop (for example the entry node), null is returned.
+ ///
+ inline Loop *getLoopFor(const BasicBlock *BB) const {
+ return LI->getLoopFor(BB);
+ }
+
+ /// operator[] - same as getLoopFor...
+ ///
+ inline const Loop *operator[](const BasicBlock *BB) const {
+ return LI->getLoopFor(BB);
+ }
+
+ /// getLoopDepth - Return the loop nesting level of the specified block...
+ ///
+ inline unsigned getLoopDepth(const BasicBlock *BB) const {
+ return LI->getLoopDepth(BB);
+ }
+
+ // isLoopHeader - True if the block is a loop header node
+ inline bool isLoopHeader(BasicBlock *BB) const {
+ return LI->isLoopHeader(BB);
+ }
projects / oota-llvm.git / blobdiff