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Diffstat (limited to 'clang-r353983/include/llvm/Analysis/LoopInfoImpl.h')
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diff --git a/clang-r353983/include/llvm/Analysis/LoopInfoImpl.h b/clang-r353983/include/llvm/Analysis/LoopInfoImpl.h new file mode 100644 index 00000000..ad425083 --- /dev/null +++ b/clang-r353983/include/llvm/Analysis/LoopInfoImpl.h @@ -0,0 +1,759 @@ +//===- llvm/Analysis/LoopInfoImpl.h - Natural Loop Calculator ---*- C++ -*-===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// +// +// This is the generic implementation of LoopInfo used for both Loops and +// MachineLoops. +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_ANALYSIS_LOOPINFOIMPL_H +#define LLVM_ANALYSIS_LOOPINFOIMPL_H + +#include "llvm/ADT/DepthFirstIterator.h" +#include "llvm/ADT/PostOrderIterator.h" +#include "llvm/ADT/STLExtras.h" +#include "llvm/ADT/SetVector.h" +#include "llvm/Analysis/LoopInfo.h" +#include "llvm/IR/Dominators.h" + +namespace llvm { + +//===----------------------------------------------------------------------===// +// APIs for simple analysis of the loop. See header notes. + +/// getExitingBlocks - Return all blocks inside the loop that have successors +/// outside of the loop. These are the blocks _inside of the current loop_ +/// which branch out. The returned list is always unique. +/// +template <class BlockT, class LoopT> +void LoopBase<BlockT, LoopT>::getExitingBlocks( + SmallVectorImpl<BlockT *> &ExitingBlocks) const { + assert(!isInvalid() && "Loop not in a valid state!"); + for (const auto BB : blocks()) + for (const auto &Succ : children<BlockT *>(BB)) + if (!contains(Succ)) { + // Not in current loop? It must be an exit block. + ExitingBlocks.push_back(BB); + break; + } +} + +/// getExitingBlock - If getExitingBlocks would return exactly one block, +/// return that block. Otherwise return null. +template <class BlockT, class LoopT> +BlockT *LoopBase<BlockT, LoopT>::getExitingBlock() const { + assert(!isInvalid() && "Loop not in a valid state!"); + SmallVector<BlockT *, 8> ExitingBlocks; + getExitingBlocks(ExitingBlocks); + if (ExitingBlocks.size() == 1) + return ExitingBlocks[0]; + return nullptr; +} + +/// getExitBlocks - Return all of the successor blocks of this loop. These +/// are the blocks _outside of the current loop_ which are branched to. +/// +template <class BlockT, class LoopT> +void LoopBase<BlockT, LoopT>::getExitBlocks( + SmallVectorImpl<BlockT *> &ExitBlocks) const { + assert(!isInvalid() && "Loop not in a valid state!"); + for (const auto BB : blocks()) + for (const auto &Succ : children<BlockT *>(BB)) + if (!contains(Succ)) + // Not in current loop? It must be an exit block. + ExitBlocks.push_back(Succ); +} + +/// getExitBlock - If getExitBlocks would return exactly one block, +/// return that block. Otherwise return null. +template <class BlockT, class LoopT> +BlockT *LoopBase<BlockT, LoopT>::getExitBlock() const { + assert(!isInvalid() && "Loop not in a valid state!"); + SmallVector<BlockT *, 8> ExitBlocks; + getExitBlocks(ExitBlocks); + if (ExitBlocks.size() == 1) + return ExitBlocks[0]; + return nullptr; +} + +template <class BlockT, class LoopT> +bool LoopBase<BlockT, LoopT>::hasDedicatedExits() const { + // Each predecessor of each exit block of a normal loop is contained + // within the loop. + SmallVector<BlockT *, 4> ExitBlocks; + getExitBlocks(ExitBlocks); + for (BlockT *EB : ExitBlocks) + for (BlockT *Predecessor : children<Inverse<BlockT *>>(EB)) + if (!contains(Predecessor)) + return false; + // All the requirements are met. + return true; +} + +template <class BlockT, class LoopT> +void LoopBase<BlockT, LoopT>::getUniqueExitBlocks( + SmallVectorImpl<BlockT *> &ExitBlocks) const { + typedef GraphTraits<BlockT *> BlockTraits; + typedef GraphTraits<Inverse<BlockT *>> InvBlockTraits; + + assert(hasDedicatedExits() && + "getUniqueExitBlocks assumes the loop has canonical form exits!"); + + SmallVector<BlockT *, 32> SwitchExitBlocks; + for (BlockT *Block : this->blocks()) { + SwitchExitBlocks.clear(); + for (BlockT *Successor : children<BlockT *>(Block)) { + // If block is inside the loop then it is not an exit block. + if (contains(Successor)) + continue; + + BlockT *FirstPred = *InvBlockTraits::child_begin(Successor); + + // If current basic block is this exit block's first predecessor then only + // insert exit block in to the output ExitBlocks vector. This ensures that + // same exit block is not inserted twice into ExitBlocks vector. + if (Block != FirstPred) + continue; + + // If a terminator has more then two successors, for example SwitchInst, + // then it is possible that there are multiple edges from current block to + // one exit block. + if (std::distance(BlockTraits::child_begin(Block), + BlockTraits::child_end(Block)) <= 2) { + ExitBlocks.push_back(Successor); + continue; + } + + // In case of multiple edges from current block to exit block, collect + // only one edge in ExitBlocks. Use switchExitBlocks to keep track of + // duplicate edges. + if (!is_contained(SwitchExitBlocks, Successor)) { + SwitchExitBlocks.push_back(Successor); + ExitBlocks.push_back(Successor); + } + } + } +} + +template <class BlockT, class LoopT> +BlockT *LoopBase<BlockT, LoopT>::getUniqueExitBlock() const { + SmallVector<BlockT *, 8> UniqueExitBlocks; + getUniqueExitBlocks(UniqueExitBlocks); + if (UniqueExitBlocks.size() == 1) + return UniqueExitBlocks[0]; + return nullptr; +} + +/// getExitEdges - Return all pairs of (_inside_block_,_outside_block_). +template <class BlockT, class LoopT> +void LoopBase<BlockT, LoopT>::getExitEdges( + SmallVectorImpl<Edge> &ExitEdges) const { + assert(!isInvalid() && "Loop not in a valid state!"); + for (const auto BB : blocks()) + for (const auto &Succ : children<BlockT *>(BB)) + if (!contains(Succ)) + // Not in current loop? It must be an exit block. + ExitEdges.emplace_back(BB, Succ); +} + +/// getLoopPreheader - If there is a preheader for this loop, return it. A +/// loop has a preheader if there is only one edge to the header of the loop +/// from outside of the loop and it is legal to hoist instructions into the +/// predecessor. If this is the case, the block branching to the header of the +/// loop is the preheader node. +/// +/// This method returns null if there is no preheader for the loop. +/// +template <class BlockT, class LoopT> +BlockT *LoopBase<BlockT, LoopT>::getLoopPreheader() const { + assert(!isInvalid() && "Loop not in a valid state!"); + // Keep track of nodes outside the loop branching to the header... + BlockT *Out = getLoopPredecessor(); + if (!Out) + return nullptr; + + // Make sure we are allowed to hoist instructions into the predecessor. + if (!Out->isLegalToHoistInto()) + return nullptr; + + // Make sure there is only one exit out of the preheader. + typedef GraphTraits<BlockT *> BlockTraits; + typename BlockTraits::ChildIteratorType SI = BlockTraits::child_begin(Out); + ++SI; + if (SI != BlockTraits::child_end(Out)) + return nullptr; // Multiple exits from the block, must not be a preheader. + + // The predecessor has exactly one successor, so it is a preheader. + return Out; +} + +/// getLoopPredecessor - If the given loop's header has exactly one unique +/// predecessor outside the loop, return it. Otherwise return null. +/// This is less strict that the loop "preheader" concept, which requires +/// the predecessor to have exactly one successor. +/// +template <class BlockT, class LoopT> +BlockT *LoopBase<BlockT, LoopT>::getLoopPredecessor() const { + assert(!isInvalid() && "Loop not in a valid state!"); + // Keep track of nodes outside the loop branching to the header... + BlockT *Out = nullptr; + + // Loop over the predecessors of the header node... + BlockT *Header = getHeader(); + for (const auto Pred : children<Inverse<BlockT *>>(Header)) { + if (!contains(Pred)) { // If the block is not in the loop... + if (Out && Out != Pred) + return nullptr; // Multiple predecessors outside the loop + Out = Pred; + } + } + + // Make sure there is only one exit out of the preheader. + assert(Out && "Header of loop has no predecessors from outside loop?"); + return Out; +} + +/// getLoopLatch - If there is a single latch block for this loop, return it. +/// A latch block is a block that contains a branch back to the header. +template <class BlockT, class LoopT> +BlockT *LoopBase<BlockT, LoopT>::getLoopLatch() const { + assert(!isInvalid() && "Loop not in a valid state!"); + BlockT *Header = getHeader(); + BlockT *Latch = nullptr; + for (const auto Pred : children<Inverse<BlockT *>>(Header)) { + if (contains(Pred)) { + if (Latch) + return nullptr; + Latch = Pred; + } + } + + return Latch; +} + +//===----------------------------------------------------------------------===// +// APIs for updating loop information after changing the CFG +// + +/// addBasicBlockToLoop - This method is used by other analyses to update loop +/// information. NewBB is set to be a new member of the current loop. +/// Because of this, it is added as a member of all parent loops, and is added +/// to the specified LoopInfo object as being in the current basic block. It +/// is not valid to replace the loop header with this method. +/// +template <class BlockT, class LoopT> +void LoopBase<BlockT, LoopT>::addBasicBlockToLoop( + BlockT *NewBB, LoopInfoBase<BlockT, LoopT> &LIB) { + assert(!isInvalid() && "Loop not in a valid state!"); +#ifndef NDEBUG + if (!Blocks.empty()) { + auto SameHeader = LIB[getHeader()]; + assert(contains(SameHeader) && getHeader() == SameHeader->getHeader() && + "Incorrect LI specified for this loop!"); + } +#endif + assert(NewBB && "Cannot add a null basic block to the loop!"); + assert(!LIB[NewBB] && "BasicBlock already in the loop!"); + + LoopT *L = static_cast<LoopT *>(this); + + // Add the loop mapping to the LoopInfo object... + LIB.BBMap[NewBB] = L; + + // Add the basic block to this loop and all parent loops... + while (L) { + L->addBlockEntry(NewBB); + L = L->getParentLoop(); + } +} + +/// replaceChildLoopWith - This is used when splitting loops up. It replaces +/// the OldChild entry in our children list with NewChild, and updates the +/// parent pointer of OldChild to be null and the NewChild to be this loop. +/// This updates the loop depth of the new child. +template <class BlockT, class LoopT> +void LoopBase<BlockT, LoopT>::replaceChildLoopWith(LoopT *OldChild, + LoopT *NewChild) { + assert(!isInvalid() && "Loop not in a valid state!"); + assert(OldChild->ParentLoop == this && "This loop is already broken!"); + assert(!NewChild->ParentLoop && "NewChild already has a parent!"); + typename std::vector<LoopT *>::iterator I = find(SubLoops, OldChild); + assert(I != SubLoops.end() && "OldChild not in loop!"); + *I = NewChild; + OldChild->ParentLoop = nullptr; + NewChild->ParentLoop = static_cast<LoopT *>(this); +} + +/// verifyLoop - Verify loop structure +template <class BlockT, class LoopT> +void LoopBase<BlockT, LoopT>::verifyLoop() const { + assert(!isInvalid() && "Loop not in a valid state!"); +#ifndef NDEBUG + assert(!Blocks.empty() && "Loop header is missing"); + + // Setup for using a depth-first iterator to visit every block in the loop. + SmallVector<BlockT *, 8> ExitBBs; + getExitBlocks(ExitBBs); + df_iterator_default_set<BlockT *> VisitSet; + VisitSet.insert(ExitBBs.begin(), ExitBBs.end()); + df_ext_iterator<BlockT *, df_iterator_default_set<BlockT *>> + BI = df_ext_begin(getHeader(), VisitSet), + BE = df_ext_end(getHeader(), VisitSet); + + // Keep track of the BBs visited. + SmallPtrSet<BlockT *, 8> VisitedBBs; + + // Check the individual blocks. + for (; BI != BE; ++BI) { + BlockT *BB = *BI; + + assert(std::any_of(GraphTraits<BlockT *>::child_begin(BB), + GraphTraits<BlockT *>::child_end(BB), + [&](BlockT *B) { return contains(B); }) && + "Loop block has no in-loop successors!"); + + assert(std::any_of(GraphTraits<Inverse<BlockT *>>::child_begin(BB), + GraphTraits<Inverse<BlockT *>>::child_end(BB), + [&](BlockT *B) { return contains(B); }) && + "Loop block has no in-loop predecessors!"); + + SmallVector<BlockT *, 2> OutsideLoopPreds; + std::for_each(GraphTraits<Inverse<BlockT *>>::child_begin(BB), + GraphTraits<Inverse<BlockT *>>::child_end(BB), + [&](BlockT *B) { + if (!contains(B)) + OutsideLoopPreds.push_back(B); + }); + + if (BB == getHeader()) { + assert(!OutsideLoopPreds.empty() && "Loop is unreachable!"); + } else if (!OutsideLoopPreds.empty()) { + // A non-header loop shouldn't be reachable from outside the loop, + // though it is permitted if the predecessor is not itself actually + // reachable. + BlockT *EntryBB = &BB->getParent()->front(); + for (BlockT *CB : depth_first(EntryBB)) + for (unsigned i = 0, e = OutsideLoopPreds.size(); i != e; ++i) + assert(CB != OutsideLoopPreds[i] && + "Loop has multiple entry points!"); + } + assert(BB != &getHeader()->getParent()->front() && + "Loop contains function entry block!"); + + VisitedBBs.insert(BB); + } + + if (VisitedBBs.size() != getNumBlocks()) { + dbgs() << "The following blocks are unreachable in the loop: "; + for (auto BB : Blocks) { + if (!VisitedBBs.count(BB)) { + dbgs() << *BB << "\n"; + } + } + assert(false && "Unreachable block in loop"); + } + + // Check the subloops. + for (iterator I = begin(), E = end(); I != E; ++I) + // Each block in each subloop should be contained within this loop. + for (block_iterator BI = (*I)->block_begin(), BE = (*I)->block_end(); + BI != BE; ++BI) { + assert(contains(*BI) && + "Loop does not contain all the blocks of a subloop!"); + } + + // Check the parent loop pointer. + if (ParentLoop) { + assert(is_contained(*ParentLoop, this) && + "Loop is not a subloop of its parent!"); + } +#endif +} + +/// verifyLoop - Verify loop structure of this loop and all nested loops. +template <class BlockT, class LoopT> +void LoopBase<BlockT, LoopT>::verifyLoopNest( + DenseSet<const LoopT *> *Loops) const { + assert(!isInvalid() && "Loop not in a valid state!"); + Loops->insert(static_cast<const LoopT *>(this)); + // Verify this loop. + verifyLoop(); + // Verify the subloops. + for (iterator I = begin(), E = end(); I != E; ++I) + (*I)->verifyLoopNest(Loops); +} + +template <class BlockT, class LoopT> +void LoopBase<BlockT, LoopT>::print(raw_ostream &OS, unsigned Depth, + bool Verbose) const { + OS.indent(Depth * 2); + if (static_cast<const LoopT *>(this)->isAnnotatedParallel()) + OS << "Parallel "; + OS << "Loop at depth " << getLoopDepth() << " containing: "; + + BlockT *H = getHeader(); + for (unsigned i = 0; i < getBlocks().size(); ++i) { + BlockT *BB = getBlocks()[i]; + if (!Verbose) { + if (i) + OS << ","; + BB->printAsOperand(OS, false); + } else + OS << "\n"; + + if (BB == H) + OS << "<header>"; + if (isLoopLatch(BB)) + OS << "<latch>"; + if (isLoopExiting(BB)) + OS << "<exiting>"; + if (Verbose) + BB->print(OS); + } + OS << "\n"; + + for (iterator I = begin(), E = end(); I != E; ++I) + (*I)->print(OS, Depth + 2); +} + +//===----------------------------------------------------------------------===// +/// Stable LoopInfo Analysis - Build a loop tree using stable iterators so the +/// result does / not depend on use list (block predecessor) order. +/// + +/// Discover a subloop with the specified backedges such that: All blocks within +/// this loop are mapped to this loop or a subloop. And all subloops within this +/// loop have their parent loop set to this loop or a subloop. +template <class BlockT, class LoopT> +static void discoverAndMapSubloop(LoopT *L, ArrayRef<BlockT *> Backedges, + LoopInfoBase<BlockT, LoopT> *LI, + const DomTreeBase<BlockT> &DomTree) { + typedef GraphTraits<Inverse<BlockT *>> InvBlockTraits; + + unsigned NumBlocks = 0; + unsigned NumSubloops = 0; + + // Perform a backward CFG traversal using a worklist. + std::vector<BlockT *> ReverseCFGWorklist(Backedges.begin(), Backedges.end()); + while (!ReverseCFGWorklist.empty()) { + BlockT *PredBB = ReverseCFGWorklist.back(); + ReverseCFGWorklist.pop_back(); + + LoopT *Subloop = LI->getLoopFor(PredBB); + if (!Subloop) { + if (!DomTree.isReachableFromEntry(PredBB)) + continue; + + // This is an undiscovered block. Map it to the current loop. + LI->changeLoopFor(PredBB, L); + ++NumBlocks; + if (PredBB == L->getHeader()) + continue; + // Push all block predecessors on the worklist. + ReverseCFGWorklist.insert(ReverseCFGWorklist.end(), + InvBlockTraits::child_begin(PredBB), + InvBlockTraits::child_end(PredBB)); + } else { + // This is a discovered block. Find its outermost discovered loop. + while (LoopT *Parent = Subloop->getParentLoop()) + Subloop = Parent; + + // If it is already discovered to be a subloop of this loop, continue. + if (Subloop == L) + continue; + + // Discover a subloop of this loop. + Subloop->setParentLoop(L); + ++NumSubloops; + NumBlocks += Subloop->getBlocksVector().capacity(); + PredBB = Subloop->getHeader(); + // Continue traversal along predecessors that are not loop-back edges from + // within this subloop tree itself. Note that a predecessor may directly + // reach another subloop that is not yet discovered to be a subloop of + // this loop, which we must traverse. + for (const auto Pred : children<Inverse<BlockT *>>(PredBB)) { + if (LI->getLoopFor(Pred) != Subloop) + ReverseCFGWorklist.push_back(Pred); + } + } + } + L->getSubLoopsVector().reserve(NumSubloops); + L->reserveBlocks(NumBlocks); +} + +/// Populate all loop data in a stable order during a single forward DFS. +template <class BlockT, class LoopT> class PopulateLoopsDFS { + typedef GraphTraits<BlockT *> BlockTraits; + typedef typename BlockTraits::ChildIteratorType SuccIterTy; + + LoopInfoBase<BlockT, LoopT> *LI; + +public: + PopulateLoopsDFS(LoopInfoBase<BlockT, LoopT> *li) : LI(li) {} + + void traverse(BlockT *EntryBlock); + +protected: + void insertIntoLoop(BlockT *Block); +}; + +/// Top-level driver for the forward DFS within the loop. +template <class BlockT, class LoopT> +void PopulateLoopsDFS<BlockT, LoopT>::traverse(BlockT *EntryBlock) { + for (BlockT *BB : post_order(EntryBlock)) + insertIntoLoop(BB); +} + +/// Add a single Block to its ancestor loops in PostOrder. If the block is a +/// subloop header, add the subloop to its parent in PostOrder, then reverse the +/// Block and Subloop vectors of the now complete subloop to achieve RPO. +template <class BlockT, class LoopT> +void PopulateLoopsDFS<BlockT, LoopT>::insertIntoLoop(BlockT *Block) { + LoopT *Subloop = LI->getLoopFor(Block); + if (Subloop && Block == Subloop->getHeader()) { + // We reach this point once per subloop after processing all the blocks in + // the subloop. + if (Subloop->getParentLoop()) + Subloop->getParentLoop()->getSubLoopsVector().push_back(Subloop); + else + LI->addTopLevelLoop(Subloop); + + // For convenience, Blocks and Subloops are inserted in postorder. Reverse + // the lists, except for the loop header, which is always at the beginning. + Subloop->reverseBlock(1); + std::reverse(Subloop->getSubLoopsVector().begin(), + Subloop->getSubLoopsVector().end()); + + Subloop = Subloop->getParentLoop(); + } + for (; Subloop; Subloop = Subloop->getParentLoop()) + Subloop->addBlockEntry(Block); +} + +/// Analyze LoopInfo discovers loops during a postorder DominatorTree traversal +/// interleaved with backward CFG traversals within each subloop +/// (discoverAndMapSubloop). The backward traversal skips inner subloops, so +/// this part of the algorithm is linear in the number of CFG edges. Subloop and +/// Block vectors are then populated during a single forward CFG traversal +/// (PopulateLoopDFS). +/// +/// During the two CFG traversals each block is seen three times: +/// 1) Discovered and mapped by a reverse CFG traversal. +/// 2) Visited during a forward DFS CFG traversal. +/// 3) Reverse-inserted in the loop in postorder following forward DFS. +/// +/// The Block vectors are inclusive, so step 3 requires loop-depth number of +/// insertions per block. +template <class BlockT, class LoopT> +void LoopInfoBase<BlockT, LoopT>::analyze(const DomTreeBase<BlockT> &DomTree) { + // Postorder traversal of the dominator tree. + const DomTreeNodeBase<BlockT> *DomRoot = DomTree.getRootNode(); + for (auto DomNode : post_order(DomRoot)) { + + BlockT *Header = DomNode->getBlock(); + SmallVector<BlockT *, 4> Backedges; + + // Check each predecessor of the potential loop header. + for (const auto Backedge : children<Inverse<BlockT *>>(Header)) { + // If Header dominates predBB, this is a new loop. Collect the backedges. + if (DomTree.dominates(Header, Backedge) && + DomTree.isReachableFromEntry(Backedge)) { + Backedges.push_back(Backedge); + } + } + // Perform a backward CFG traversal to discover and map blocks in this loop. + if (!Backedges.empty()) { + LoopT *L = AllocateLoop(Header); + discoverAndMapSubloop(L, ArrayRef<BlockT *>(Backedges), this, DomTree); + } + } + // Perform a single forward CFG traversal to populate block and subloop + // vectors for all loops. + PopulateLoopsDFS<BlockT, LoopT> DFS(this); + DFS.traverse(DomRoot->getBlock()); +} + +template <class BlockT, class LoopT> +SmallVector<LoopT *, 4> LoopInfoBase<BlockT, LoopT>::getLoopsInPreorder() { + SmallVector<LoopT *, 4> PreOrderLoops, PreOrderWorklist; + // The outer-most loop actually goes into the result in the same relative + // order as we walk it. But LoopInfo stores the top level loops in reverse + // program order so for here we reverse it to get forward program order. + // FIXME: If we change the order of LoopInfo we will want to remove the + // reverse here. + for (LoopT *RootL : reverse(*this)) { + assert(PreOrderWorklist.empty() && + "Must start with an empty preorder walk worklist."); + PreOrderWorklist.push_back(RootL); + do { + LoopT *L = PreOrderWorklist.pop_back_val(); + // Sub-loops are stored in forward program order, but will process the + // worklist backwards so append them in reverse order. + PreOrderWorklist.append(L->rbegin(), L->rend()); + PreOrderLoops.push_back(L); + } while (!PreOrderWorklist.empty()); + } + + return PreOrderLoops; +} + +template <class BlockT, class LoopT> +SmallVector<LoopT *, 4> +LoopInfoBase<BlockT, LoopT>::getLoopsInReverseSiblingPreorder() { + SmallVector<LoopT *, 4> PreOrderLoops, PreOrderWorklist; + // The outer-most loop actually goes into the result in the same relative + // order as we walk it. LoopInfo stores the top level loops in reverse + // program order so we walk in order here. + // FIXME: If we change the order of LoopInfo we will want to add a reverse + // here. + for (LoopT *RootL : *this) { + assert(PreOrderWorklist.empty() && + "Must start with an empty preorder walk worklist."); + PreOrderWorklist.push_back(RootL); + do { + LoopT *L = PreOrderWorklist.pop_back_val(); + // Sub-loops are stored in forward program order, but will process the + // worklist backwards so we can just append them in order. + PreOrderWorklist.append(L->begin(), L->end()); + PreOrderLoops.push_back(L); + } while (!PreOrderWorklist.empty()); + } + + return PreOrderLoops; +} + +// Debugging +template <class BlockT, class LoopT> +void LoopInfoBase<BlockT, LoopT>::print(raw_ostream &OS) const { + for (unsigned i = 0; i < TopLevelLoops.size(); ++i) + TopLevelLoops[i]->print(OS); +#if 0 + for (DenseMap<BasicBlock*, LoopT*>::const_iterator I = BBMap.begin(), + E = BBMap.end(); I != E; ++I) + OS << "BB '" << I->first->getName() << "' level = " + << I->second->getLoopDepth() << "\n"; +#endif +} + +template <typename T> +bool compareVectors(std::vector<T> &BB1, std::vector<T> &BB2) { + llvm::sort(BB1); + llvm::sort(BB2); + return BB1 == BB2; +} + +template <class BlockT, class LoopT> +void addInnerLoopsToHeadersMap(DenseMap<BlockT *, const LoopT *> &LoopHeaders, + const LoopInfoBase<BlockT, LoopT> &LI, + const LoopT &L) { + LoopHeaders[L.getHeader()] = &L; + for (LoopT *SL : L) + addInnerLoopsToHeadersMap(LoopHeaders, LI, *SL); +} + +#ifndef NDEBUG +template <class BlockT, class LoopT> +static void compareLoops(const LoopT *L, const LoopT *OtherL, + DenseMap<BlockT *, const LoopT *> &OtherLoopHeaders) { + BlockT *H = L->getHeader(); + BlockT *OtherH = OtherL->getHeader(); + assert(H == OtherH && + "Mismatched headers even though found in the same map entry!"); + + assert(L->getLoopDepth() == OtherL->getLoopDepth() && + "Mismatched loop depth!"); + const LoopT *ParentL = L, *OtherParentL = OtherL; + do { + assert(ParentL->getHeader() == OtherParentL->getHeader() && + "Mismatched parent loop headers!"); + ParentL = ParentL->getParentLoop(); + OtherParentL = OtherParentL->getParentLoop(); + } while (ParentL); + + for (const LoopT *SubL : *L) { + BlockT *SubH = SubL->getHeader(); + const LoopT *OtherSubL = OtherLoopHeaders.lookup(SubH); + assert(OtherSubL && "Inner loop is missing in computed loop info!"); + OtherLoopHeaders.erase(SubH); + compareLoops(SubL, OtherSubL, OtherLoopHeaders); + } + + std::vector<BlockT *> BBs = L->getBlocks(); + std::vector<BlockT *> OtherBBs = OtherL->getBlocks(); + assert(compareVectors(BBs, OtherBBs) && + "Mismatched basic blocks in the loops!"); + + const SmallPtrSetImpl<const BlockT *> &BlocksSet = L->getBlocksSet(); + const SmallPtrSetImpl<const BlockT *> &OtherBlocksSet = L->getBlocksSet(); + assert(BlocksSet.size() == OtherBlocksSet.size() && + std::all_of(BlocksSet.begin(), BlocksSet.end(), + [&OtherBlocksSet](const BlockT *BB) { + return OtherBlocksSet.count(BB); + }) && + "Mismatched basic blocks in BlocksSets!"); +} +#endif + +template <class BlockT, class LoopT> +void LoopInfoBase<BlockT, LoopT>::verify( + const DomTreeBase<BlockT> &DomTree) const { + DenseSet<const LoopT *> Loops; + for (iterator I = begin(), E = end(); I != E; ++I) { + assert(!(*I)->getParentLoop() && "Top-level loop has a parent!"); + (*I)->verifyLoopNest(&Loops); + } + +// Verify that blocks are mapped to valid loops. +#ifndef NDEBUG + for (auto &Entry : BBMap) { + const BlockT *BB = Entry.first; + LoopT *L = Entry.second; + assert(Loops.count(L) && "orphaned loop"); + assert(L->contains(BB) && "orphaned block"); + for (LoopT *ChildLoop : *L) + assert(!ChildLoop->contains(BB) && + "BBMap should point to the innermost loop containing BB"); + } + + // Recompute LoopInfo to verify loops structure. + LoopInfoBase<BlockT, LoopT> OtherLI; + OtherLI.analyze(DomTree); + + // Build a map we can use to move from our LI to the computed one. This + // allows us to ignore the particular order in any layer of the loop forest + // while still comparing the structure. + DenseMap<BlockT *, const LoopT *> OtherLoopHeaders; + for (LoopT *L : OtherLI) + addInnerLoopsToHeadersMap(OtherLoopHeaders, OtherLI, *L); + + // Walk the top level loops and ensure there is a corresponding top-level + // loop in the computed version and then recursively compare those loop + // nests. + for (LoopT *L : *this) { + BlockT *Header = L->getHeader(); + const LoopT *OtherL = OtherLoopHeaders.lookup(Header); + assert(OtherL && "Top level loop is missing in computed loop info!"); + // Now that we've matched this loop, erase its header from the map. + OtherLoopHeaders.erase(Header); + // And recursively compare these loops. + compareLoops(L, OtherL, OtherLoopHeaders); + } + + // Any remaining entries in the map are loops which were found when computing + // a fresh LoopInfo but not present in the current one. + if (!OtherLoopHeaders.empty()) { + for (const auto &HeaderAndLoop : OtherLoopHeaders) + dbgs() << "Found new loop: " << *HeaderAndLoop.second << "\n"; + llvm_unreachable("Found new loops when recomputing LoopInfo!"); + } +#endif +} + +} // End llvm namespace + +#endif |