#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/Analysis/LoopInfo.h"
#include "llvm/IR/Dominators.h"
namespace llvm {
template<class BlockT, class LoopT>
void LoopBase<BlockT, LoopT>::
getExitingBlocks(SmallVectorImpl<BlockT *> &ExitingBlocks) const {
typedef GraphTraits<BlockT*> BlockTraits;
for (block_iterator BI = block_begin(), BE = block_end(); BI != BE; ++BI)
for (typename BlockTraits::ChildIteratorType I =
BlockTraits::child_begin(*BI), E = BlockTraits::child_end(*BI);
I != E; ++I)
if (!contains(*I)) {
ExitingBlocks.push_back(*BI);
break;
}
}
template<class BlockT, class LoopT>
BlockT *LoopBase<BlockT, LoopT>::getExitingBlock() const {
SmallVector<BlockT*, 8> ExitingBlocks;
getExitingBlocks(ExitingBlocks);
if (ExitingBlocks.size() == 1)
return ExitingBlocks[0];
return nullptr;
}
template<class BlockT, class LoopT>
void LoopBase<BlockT, LoopT>::
getExitBlocks(SmallVectorImpl<BlockT*> &ExitBlocks) const {
typedef GraphTraits<BlockT*> BlockTraits;
for (block_iterator BI = block_begin(), BE = block_end(); BI != BE; ++BI)
for (typename BlockTraits::ChildIteratorType I =
BlockTraits::child_begin(*BI), E = BlockTraits::child_end(*BI);
I != E; ++I)
if (!contains(*I))
ExitBlocks.push_back(*I);
}
template<class BlockT, class LoopT>
BlockT *LoopBase<BlockT, LoopT>::getExitBlock() const {
SmallVector<BlockT*, 8> ExitBlocks;
getExitBlocks(ExitBlocks);
if (ExitBlocks.size() == 1)
return ExitBlocks[0];
return nullptr;
}
template<class BlockT, class LoopT>
void LoopBase<BlockT, LoopT>::
getExitEdges(SmallVectorImpl<Edge> &ExitEdges) const {
typedef GraphTraits<BlockT*> BlockTraits;
for (block_iterator BI = block_begin(), BE = block_end(); BI != BE; ++BI)
for (typename BlockTraits::ChildIteratorType I =
BlockTraits::child_begin(*BI), E = BlockTraits::child_end(*BI);
I != E; ++I)
if (!contains(*I))
ExitEdges.push_back(Edge(*BI, *I));
}
template<class BlockT, class LoopT>
BlockT *LoopBase<BlockT, LoopT>::getLoopPreheader() const {
BlockT *Out = getLoopPredecessor();
if (!Out) return nullptr;
typedef GraphTraits<BlockT*> BlockTraits;
typename BlockTraits::ChildIteratorType SI = BlockTraits::child_begin(Out);
++SI;
if (SI != BlockTraits::child_end(Out))
return nullptr;
return Out;
}
template<class BlockT, class LoopT>
BlockT *LoopBase<BlockT, LoopT>::getLoopPredecessor() const {
BlockT *Out = nullptr;
BlockT *Header = getHeader();
typedef GraphTraits<Inverse<BlockT*> > InvBlockTraits;
for (typename InvBlockTraits::ChildIteratorType PI =
InvBlockTraits::child_begin(Header),
PE = InvBlockTraits::child_end(Header); PI != PE; ++PI) {
typename InvBlockTraits::NodeType *N = *PI;
if (!contains(N)) { if (Out && Out != N)
return nullptr; Out = N;
}
}
assert(Out && "Header of loop has no predecessors from outside loop?");
return Out;
}
template<class BlockT, class LoopT>
BlockT *LoopBase<BlockT, LoopT>::getLoopLatch() const {
BlockT *Header = getHeader();
typedef GraphTraits<Inverse<BlockT*> > InvBlockTraits;
typename InvBlockTraits::ChildIteratorType PI =
InvBlockTraits::child_begin(Header);
typename InvBlockTraits::ChildIteratorType PE =
InvBlockTraits::child_end(Header);
BlockT *Latch = nullptr;
for (; PI != PE; ++PI) {
typename InvBlockTraits::NodeType *N = *PI;
if (contains(N)) {
if (Latch) return nullptr;
Latch = N;
}
}
return Latch;
}
template<class BlockT, class LoopT>
void LoopBase<BlockT, LoopT>::
addBasicBlockToLoop(BlockT *NewBB, LoopInfoBase<BlockT, LoopT> &LIB) {
assert((Blocks.empty() || LIB[getHeader()] == this) &&
"Incorrect LI specified for this loop!");
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);
LIB.BBMap[NewBB] = L;
while (L) {
L->addBlockEntry(NewBB);
L = L->getParentLoop();
}
}
template<class BlockT, class LoopT>
void LoopBase<BlockT, LoopT>::
replaceChildLoopWith(LoopT *OldChild, LoopT *NewChild) {
assert(OldChild->ParentLoop == this && "This loop is already broken!");
assert(!NewChild->ParentLoop && "NewChild already has a parent!");
typename std::vector<LoopT *>::iterator I =
std::find(SubLoops.begin(), SubLoops.end(), OldChild);
assert(I != SubLoops.end() && "OldChild not in loop!");
*I = NewChild;
OldChild->ParentLoop = nullptr;
NewChild->ParentLoop = static_cast<LoopT *>(this);
}
template<class BlockT, class LoopT>
void LoopBase<BlockT, LoopT>::verifyLoop() const {
#ifndef NDEBUG
assert(!Blocks.empty() && "Loop header is missing");
SmallVector<BlockT*, 8> ExitBBs;
getExitBlocks(ExitBBs);
llvm::SmallPtrSet<BlockT*, 8> VisitSet;
VisitSet.insert(ExitBBs.begin(), ExitBBs.end());
df_ext_iterator<BlockT*, llvm::SmallPtrSet<BlockT*, 8> >
BI = df_ext_begin(getHeader(), VisitSet),
BE = df_ext_end(getHeader(), VisitSet);
unsigned NumVisited = 0;
for ( ; BI != BE; ++BI) {
BlockT *BB = *BI;
bool HasInsideLoopSuccs = false;
bool HasInsideLoopPreds = false;
SmallVector<BlockT *, 2> OutsideLoopPreds;
typedef GraphTraits<BlockT*> BlockTraits;
for (typename BlockTraits::ChildIteratorType SI =
BlockTraits::child_begin(BB), SE = BlockTraits::child_end(BB);
SI != SE; ++SI)
if (contains(*SI)) {
HasInsideLoopSuccs = true;
break;
}
typedef GraphTraits<Inverse<BlockT*> > InvBlockTraits;
for (typename InvBlockTraits::ChildIteratorType PI =
InvBlockTraits::child_begin(BB), PE = InvBlockTraits::child_end(BB);
PI != PE; ++PI) {
BlockT *N = *PI;
if (contains(N))
HasInsideLoopPreds = true;
else
OutsideLoopPreds.push_back(N);
}
if (BB == getHeader()) {
assert(!OutsideLoopPreds.empty() && "Loop is unreachable!");
} else if (!OutsideLoopPreds.empty()) {
BlockT *EntryBB = BB->getParent()->begin();
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(HasInsideLoopPreds && "Loop block has no in-loop predecessors!");
assert(HasInsideLoopSuccs && "Loop block has no in-loop successors!");
assert(BB != getHeader()->getParent()->begin() &&
"Loop contains function entry block!");
NumVisited++;
}
assert(NumVisited == getNumBlocks() && "Unreachable block in loop");
for (iterator I = begin(), E = end(); I != E; ++I)
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!");
}
if (ParentLoop) {
assert(std::find(ParentLoop->begin(), ParentLoop->end(), this) !=
ParentLoop->end() &&
"Loop is not a subloop of its parent!");
}
#endif
}
template<class BlockT, class LoopT>
void LoopBase<BlockT, LoopT>::verifyLoopNest(
DenseSet<const LoopT*> *Loops) const {
Loops->insert(static_cast<const LoopT *>(this));
verifyLoop();
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) const {
OS.indent(Depth*2) << "Loop at depth " << getLoopDepth()
<< " containing: ";
for (unsigned i = 0; i < getBlocks().size(); ++i) {
if (i) OS << ",";
BlockT *BB = getBlocks()[i];
BB->printAsOperand(OS, false);
if (BB == getHeader()) OS << "<header>";
if (BB == getLoopLatch()) OS << "<latch>";
if (isLoopExiting(BB)) OS << "<exiting>";
}
OS << "\n";
for (iterator I = begin(), E = end(); I != E; ++I)
(*I)->print(OS, Depth+2);
}
template<class BlockT, class LoopT>
static void discoverAndMapSubloop(LoopT *L, ArrayRef<BlockT*> Backedges,
LoopInfoBase<BlockT, LoopT> *LI,
DominatorTreeBase<BlockT> &DomTree) {
typedef GraphTraits<Inverse<BlockT*> > InvBlockTraits;
unsigned NumBlocks = 0;
unsigned NumSubloops = 0;
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;
LI->changeLoopFor(PredBB, L);
++NumBlocks;
if (PredBB == L->getHeader())
continue;
ReverseCFGWorklist.insert(ReverseCFGWorklist.end(),
InvBlockTraits::child_begin(PredBB),
InvBlockTraits::child_end(PredBB));
}
else {
while (LoopT *Parent = Subloop->getParentLoop())
Subloop = Parent;
if (Subloop == L)
continue;
Subloop->setParentLoop(L);
++NumSubloops;
NumBlocks += Subloop->getBlocks().capacity();
PredBB = Subloop->getHeader();
for (typename InvBlockTraits::ChildIteratorType PI =
InvBlockTraits::child_begin(PredBB),
PE = InvBlockTraits::child_end(PredBB); PI != PE; ++PI) {
if (LI->getLoopFor(*PI) != Subloop)
ReverseCFGWorklist.push_back(*PI);
}
}
}
L->getSubLoopsVector().reserve(NumSubloops);
L->reserveBlocks(NumBlocks);
}
namespace {
template<class BlockT, class LoopT>
class PopulateLoopsDFS {
typedef GraphTraits<BlockT*> BlockTraits;
typedef typename BlockTraits::ChildIteratorType SuccIterTy;
LoopInfoBase<BlockT, LoopT> *LI;
DenseSet<const BlockT *> VisitedBlocks;
std::vector<std::pair<BlockT*, SuccIterTy> > DFSStack;
public:
PopulateLoopsDFS(LoopInfoBase<BlockT, LoopT> *li):
LI(li) {}
void traverse(BlockT *EntryBlock);
protected:
void insertIntoLoop(BlockT *Block);
BlockT *dfsSource() { return DFSStack.back().first; }
SuccIterTy &dfsSucc() { return DFSStack.back().second; }
SuccIterTy dfsSuccEnd() { return BlockTraits::child_end(dfsSource()); }
void pushBlock(BlockT *Block) {
DFSStack.push_back(std::make_pair(Block, BlockTraits::child_begin(Block)));
}
};
}
template<class BlockT, class LoopT>
void PopulateLoopsDFS<BlockT, LoopT>::traverse(BlockT *EntryBlock) {
pushBlock(EntryBlock);
VisitedBlocks.insert(EntryBlock);
while (!DFSStack.empty()) {
while (dfsSucc() != dfsSuccEnd()) {
BlockT *BB = *dfsSucc();
++dfsSucc();
if (!VisitedBlocks.insert(BB).second)
continue;
pushBlock(BB);
}
insertIntoLoop(dfsSource());
DFSStack.pop_back();
}
}
template<class BlockT, class LoopT>
void PopulateLoopsDFS<BlockT, LoopT>::insertIntoLoop(BlockT *Block) {
LoopT *Subloop = LI->getLoopFor(Block);
if (Subloop && Block == Subloop->getHeader()) {
if (Subloop->getParentLoop())
Subloop->getParentLoop()->getSubLoopsVector().push_back(Subloop);
else
LI->addTopLevelLoop(Subloop);
Subloop->reverseBlock(1);
std::reverse(Subloop->getSubLoopsVector().begin(),
Subloop->getSubLoopsVector().end());
Subloop = Subloop->getParentLoop();
}
for (; Subloop; Subloop = Subloop->getParentLoop())
Subloop->addBlockEntry(Block);
}
template<class BlockT, class LoopT>
void LoopInfoBase<BlockT, LoopT>::
Analyze(DominatorTreeBase<BlockT> &DomTree) {
DomTreeNodeBase<BlockT>* DomRoot = DomTree.getRootNode();
for (po_iterator<DomTreeNodeBase<BlockT>*> DomIter = po_begin(DomRoot),
DomEnd = po_end(DomRoot); DomIter != DomEnd; ++DomIter) {
BlockT *Header = DomIter->getBlock();
SmallVector<BlockT *, 4> Backedges;
typedef GraphTraits<Inverse<BlockT*> > InvBlockTraits;
for (typename InvBlockTraits::ChildIteratorType PI =
InvBlockTraits::child_begin(Header),
PE = InvBlockTraits::child_end(Header); PI != PE; ++PI) {
BlockT *Backedge = *PI;
if (DomTree.dominates(Header, Backedge)
&& DomTree.isReachableFromEntry(Backedge)) {
Backedges.push_back(Backedge);
}
}
if (!Backedges.empty()) {
LoopT *L = new LoopT(Header);
discoverAndMapSubloop(L, ArrayRef<BlockT*>(Backedges), this, DomTree);
}
}
PopulateLoopsDFS<BlockT, LoopT> DFS(this);
DFS.traverse(DomRoot->getBlock());
}
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
}
}
#endif