//
//===----------------------------------------------------------------------===//
//
-// This file defines the following classes:
-// 1. DominatorTree: Represent dominators as an explicit tree structure.
-// 2. DominanceFrontier: Calculate and hold the dominance frontier for a
-// function.
-//
-// These data structures are listed in increasing order of complexity. It
-// takes longer to calculate the dominator frontier, for example, than the
-// DominatorTree mapping.
+// This file defines the DominatorTree class, which provides fast and efficient
+// dominance queries.
//
//===----------------------------------------------------------------------===//
#define LLVM_ANALYSIS_DOMINATORS_H
#include "llvm/Pass.h"
-#include "llvm/BasicBlock.h"
#include "llvm/Function.h"
-#include "llvm/Instruction.h"
-#include "llvm/Instructions.h"
#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/GraphTraits.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
-#include "llvm/Assembly/Writer.h"
#include "llvm/Support/CFG.h"
#include "llvm/Support/Compiler.h"
+#include "llvm/Support/raw_ostream.h"
#include <algorithm>
-#include <map>
-#include <set>
namespace llvm {
Roots(), IsPostDominators(isPostDom) {}
public:
- /// getRoots - Return the root blocks of the current CFG. This may include
+ /// getRoots - Return the root blocks of the current CFG. This may include
/// multiple blocks if we are computing post dominators. For forward
/// dominators, this will always be a single block (the entry node).
///
typedef typename std::vector<DomTreeNodeBase<NodeT> *>::iterator iterator;
typedef typename std::vector<DomTreeNodeBase<NodeT> *>::const_iterator
const_iterator;
-
+
iterator begin() { return Children.begin(); }
iterator end() { return Children.end(); }
const_iterator begin() const { return Children.begin(); }
const_iterator end() const { return Children.end(); }
-
+
NodeT *getBlock() const { return TheBB; }
DomTreeNodeBase<NodeT> *getIDom() const { return IDom; }
const std::vector<DomTreeNodeBase<NodeT>*> &getChildren() const {
return Children;
}
-
+
DomTreeNodeBase(NodeT *BB, DomTreeNodeBase<NodeT> *iDom)
: TheBB(BB), IDom(iDom), DFSNumIn(-1), DFSNumOut(-1) { }
-
+
DomTreeNodeBase<NodeT> *addChild(DomTreeNodeBase<NodeT> *C) {
Children.push_back(C);
return C;
}
-
+
size_t getNumChildren() const {
return Children.size();
}
-
+
+ void clearAllChildren() {
+ Children.clear();
+ }
+
+ bool compare(DomTreeNodeBase<NodeT> *Other) {
+ if (getNumChildren() != Other->getNumChildren())
+ return true;
+
+ SmallPtrSet<NodeT *, 4> OtherChildren;
+ for (iterator I = Other->begin(), E = Other->end(); I != E; ++I) {
+ NodeT *Nd = (*I)->getBlock();
+ OtherChildren.insert(Nd);
+ }
+
+ for (iterator I = begin(), E = end(); I != E; ++I) {
+ NodeT *N = (*I)->getBlock();
+ if (OtherChildren.count(N) == 0)
+ return true;
+ }
+ return false;
+ }
+
void setIDom(DomTreeNodeBase<NodeT> *NewIDom) {
assert(IDom && "No immediate dominator?");
if (IDom != NewIDom) {
IDom->Children.push_back(this);
}
}
-
+
/// getDFSNumIn/getDFSNumOut - These are an internal implementation detail, do
/// not call them.
unsigned getDFSNumIn() const { return DFSNumIn; }
EXTERN_TEMPLATE_INSTANTIATION(class DomTreeNodeBase<MachineBasicBlock>);
template<class NodeT>
-static std::ostream &operator<<(std::ostream &o,
- const DomTreeNodeBase<NodeT> *Node) {
+inline raw_ostream &operator<<(raw_ostream &o,
+ const DomTreeNodeBase<NodeT> *Node) {
if (Node->getBlock())
WriteAsOperand(o, Node->getBlock(), false);
else
o << " <<exit node>>";
-
+
o << " {" << Node->getDFSNumIn() << "," << Node->getDFSNumOut() << "}";
-
+
return o << "\n";
}
template<class NodeT>
-static void PrintDomTree(const DomTreeNodeBase<NodeT> *N, std::ostream &o,
+inline void PrintDomTree(const DomTreeNodeBase<NodeT> *N, raw_ostream &o,
unsigned Lev) {
- o << std::string(2*Lev, ' ') << "[" << Lev << "] " << N;
+ o.indent(2*Lev) << "[" << Lev << "] " << N;
for (typename DomTreeNodeBase<NodeT>::const_iterator I = N->begin(),
E = N->end(); I != E; ++I)
PrintDomTree<NodeT>(*I, o, Lev+1);
template<class NodeT>
class DominatorTreeBase : public DominatorBase<NodeT> {
+ bool dominatedBySlowTreeWalk(const DomTreeNodeBase<NodeT> *A,
+ const DomTreeNodeBase<NodeT> *B) const {
+ assert(A != B);
+ assert(isReachableFromEntry(B));
+ assert(isReachableFromEntry(A));
+
+ const DomTreeNodeBase<NodeT> *IDom;
+ while ((IDom = B->getIDom()) != 0 && IDom != A && IDom != B)
+ B = IDom; // Walk up the tree
+ return IDom != 0;
+ }
+
protected:
typedef DenseMap<NodeT*, DomTreeNodeBase<NodeT>*> DomTreeNodeMapType;
DomTreeNodeMapType DomTreeNodes;
// Information record used during immediate dominators computation.
struct InfoRec {
unsigned DFSNum;
+ unsigned Parent;
unsigned Semi;
- unsigned Size;
- NodeT *Label, *Child;
- unsigned Parent, Ancestor;
+ NodeT *Label;
- std::vector<NodeT*> Bucket;
-
- InfoRec() : DFSNum(0), Semi(0), Size(0), Label(0), Child(0), Parent(0),
- Ancestor(0) {}
+ InfoRec() : DFSNum(0), Parent(0), Semi(0), Label(0) {}
};
DenseMap<NodeT*, NodeT*> IDoms;
DenseMap<NodeT*, InfoRec> Info;
void reset() {
- for (typename DomTreeNodeMapType::iterator I = this->DomTreeNodes.begin(),
+ for (typename DomTreeNodeMapType::iterator I = this->DomTreeNodes.begin(),
E = DomTreeNodes.end(); I != E; ++I)
delete I->second;
DomTreeNodes.clear();
Vertex.clear();
RootNode = 0;
}
-
+
// NewBB is split and now it has one successor. Update dominator tree to
// reflect this change.
template<class N, class GraphT>
void Split(DominatorTreeBase<typename GraphT::NodeType>& DT,
typename GraphT::NodeType* NewBB) {
- assert(std::distance(GraphT::child_begin(NewBB), GraphT::child_end(NewBB)) == 1
- && "NewBB should have a single successor!");
+ assert(std::distance(GraphT::child_begin(NewBB),
+ GraphT::child_end(NewBB)) == 1 &&
+ "NewBB should have a single successor!");
typename GraphT::NodeType* NewBBSucc = *GraphT::child_begin(NewBB);
std::vector<typename GraphT::NodeType*> PredBlocks;
- for (typename GraphTraits<Inverse<N> >::ChildIteratorType PI =
- GraphTraits<Inverse<N> >::child_begin(NewBB),
- PE = GraphTraits<Inverse<N> >::child_end(NewBB); PI != PE; ++PI)
- PredBlocks.push_back(*PI);
-
- assert(!PredBlocks.empty() && "No predblocks??");
-
- // The newly inserted basic block will dominate existing basic blocks iff the
- // PredBlocks dominate all of the non-pred blocks. If all predblocks dominate
- // the non-pred blocks, then they all must be the same block!
- //
- bool NewBBDominatesNewBBSucc = true;
- {
- typename GraphT::NodeType* OnePred = PredBlocks[0];
- unsigned i = 1, e = PredBlocks.size();
- for (i = 1; !DT.isReachableFromEntry(OnePred); ++i) {
- assert(i != e && "Didn't find reachable pred?");
- OnePred = PredBlocks[i];
- }
-
- for (; i != e; ++i)
- if (PredBlocks[i] != OnePred && DT.isReachableFromEntry(OnePred)) {
- NewBBDominatesNewBBSucc = false;
- break;
- }
-
- if (NewBBDominatesNewBBSucc)
- for (typename GraphTraits<Inverse<N> >::ChildIteratorType PI =
- GraphTraits<Inverse<N> >::child_begin(NewBBSucc),
- E = GraphTraits<Inverse<N> >::child_end(NewBBSucc); PI != E; ++PI)
- if (*PI != NewBB && !DT.dominates(NewBBSucc, *PI)) {
- NewBBDominatesNewBBSucc = false;
- break;
- }
- }
-
- // The other scenario where the new block can dominate its successors are when
- // all predecessors of NewBBSucc that are not NewBB are dominated by NewBBSucc
- // already.
- if (!NewBBDominatesNewBBSucc) {
- NewBBDominatesNewBBSucc = true;
- for (typename GraphTraits<Inverse<N> >::ChildIteratorType PI =
- GraphTraits<Inverse<N> >::child_begin(NewBBSucc),
- E = GraphTraits<Inverse<N> >::child_end(NewBBSucc); PI != E; ++PI)
- if (*PI != NewBB && !DT.dominates(NewBBSucc, *PI)) {
- NewBBDominatesNewBBSucc = false;
- break;
- }
+ typedef GraphTraits<Inverse<N> > InvTraits;
+ for (typename InvTraits::ChildIteratorType PI =
+ InvTraits::child_begin(NewBB),
+ PE = InvTraits::child_end(NewBB); PI != PE; ++PI)
+ PredBlocks.push_back(*PI);
+
+ assert(!PredBlocks.empty() && "No predblocks?");
+
+ bool NewBBDominatesNewBBSucc = true;
+ for (typename InvTraits::ChildIteratorType PI =
+ InvTraits::child_begin(NewBBSucc),
+ E = InvTraits::child_end(NewBBSucc); PI != E; ++PI) {
+ typename InvTraits::NodeType *ND = *PI;
+ if (ND != NewBB && !DT.dominates(NewBBSucc, ND) &&
+ DT.isReachableFromEntry(ND)) {
+ NewBBDominatesNewBBSucc = false;
+ break;
+ }
}
// Find NewBB's immediate dominator and create new dominator tree node for
NewBBIDom = PredBlocks[i];
break;
}
- assert(i != PredBlocks.size() && "No reachable preds?");
+
+ // It's possible that none of the predecessors of NewBB are reachable;
+ // in that case, NewBB itself is unreachable, so nothing needs to be
+ // changed.
+ if (!NewBBIDom)
+ return;
+
for (i = i + 1; i < PredBlocks.size(); ++i) {
if (DT.isReachableFromEntry(PredBlocks[i]))
NewBBIDom = DT.findNearestCommonDominator(NewBBIDom, PredBlocks[i]);
}
- assert(NewBBIDom && "No immediate dominator found??");
// Create the new dominator tree node... and set the idom of NewBB.
DomTreeNodeBase<NodeT> *NewBBNode = DT.addNewBlock(NewBB, NewBBIDom);
: DominatorBase<NodeT>(isPostDom), DFSInfoValid(false), SlowQueries(0) {}
virtual ~DominatorTreeBase() { reset(); }
- // FIXME: Should remove this
- virtual bool runOnFunction(Function &F) { return false; }
+ /// compare - Return false if the other dominator tree base matches this
+ /// dominator tree base. Otherwise return true.
+ bool compare(DominatorTreeBase &Other) const {
+
+ const DomTreeNodeMapType &OtherDomTreeNodes = Other.DomTreeNodes;
+ if (DomTreeNodes.size() != OtherDomTreeNodes.size())
+ return true;
+
+ for (typename DomTreeNodeMapType::const_iterator
+ I = this->DomTreeNodes.begin(),
+ E = this->DomTreeNodes.end(); I != E; ++I) {
+ NodeT *BB = I->first;
+ typename DomTreeNodeMapType::const_iterator OI = OtherDomTreeNodes.find(BB);
+ if (OI == OtherDomTreeNodes.end())
+ return true;
+
+ DomTreeNodeBase<NodeT>* MyNd = I->second;
+ DomTreeNodeBase<NodeT>* OtherNd = OI->second;
+
+ if (MyNd->compare(OtherNd))
+ return true;
+ }
+
+ return false;
+ }
virtual void releaseMemory() { reset(); }
/// block. This is the same as using operator[] on this class.
///
inline DomTreeNodeBase<NodeT> *getNode(NodeT *BB) const {
- typename DomTreeNodeMapType::const_iterator I = DomTreeNodes.find(BB);
- return I != DomTreeNodes.end() ? I->second : 0;
+ return DomTreeNodes.lookup(BB);
}
/// getRootNode - This returns the entry node for the CFG of the function. If
DomTreeNodeBase<NodeT> *getRootNode() { return RootNode; }
const DomTreeNodeBase<NodeT> *getRootNode() const { return RootNode; }
- /// properlyDominates - Returns true iff this dominates N and this != N.
+ /// properlyDominates - Returns true if this dominates N and this != N.
/// Note that this is not a constant time operation!
///
bool properlyDominates(const DomTreeNodeBase<NodeT> *A,
- DomTreeNodeBase<NodeT> *B) const {
- if (A == 0 || B == 0) return false;
- return dominatedBySlowTreeWalk(A, B);
- }
-
- inline bool properlyDominates(NodeT *A, NodeT *B) {
- return properlyDominates(getNode(A), getNode(B));
- }
-
- bool dominatedBySlowTreeWalk(const DomTreeNodeBase<NodeT> *A,
- const DomTreeNodeBase<NodeT> *B) const {
- const DomTreeNodeBase<NodeT> *IDom;
- if (A == 0 || B == 0) return false;
- while ((IDom = B->getIDom()) != 0 && IDom != A && IDom != B)
- B = IDom; // Walk up the tree
- return IDom != 0;
+ const DomTreeNodeBase<NodeT> *B) {
+ if (A == 0 || B == 0)
+ return false;
+ if (A == B)
+ return false;
+ return dominates(A, B);
}
+ bool properlyDominates(const NodeT *A, const NodeT *B);
/// isReachableFromEntry - Return true if A is dominated by the entry
/// block of the function containing it.
- bool isReachableFromEntry(NodeT* A) {
- assert (!this->isPostDominator()
- && "This is not implemented for post dominators");
- return dominates(&A->getParent()->front(), A);
+ bool isReachableFromEntry(const NodeT* A) const {
+ assert(!this->isPostDominator() &&
+ "This is not implemented for post dominators");
+ return isReachableFromEntry(getNode(const_cast<NodeT *>(A)));
+ }
+
+ inline bool isReachableFromEntry(const DomTreeNodeBase<NodeT> *A) const {
+ return A;
}
-
- /// dominates - Returns true iff A dominates B. Note that this is not a
+
+ /// dominates - Returns true if A dominates B. Note that this is not a
/// constant time operation!
///
inline bool dominates(const DomTreeNodeBase<NodeT> *A,
- DomTreeNodeBase<NodeT> *B) {
- if (B == A)
- return true; // A node trivially dominates itself.
+ const DomTreeNodeBase<NodeT> *B) {
+ // A node trivially dominates itself.
+ if (B == A)
+ return true;
- if (A == 0 || B == 0)
+ // An unreachable node is dominated by anything.
+ if (!isReachableFromEntry(B))
+ return true;
+
+ // And dominates nothing.
+ if (!isReachableFromEntry(A))
return false;
+ // Compare the result of the tree walk and the dfs numbers, if expensive
+ // checks are enabled.
+#ifdef XDEBUG
+ assert((!DFSInfoValid ||
+ (dominatedBySlowTreeWalk(A, B) == B->DominatedBy(A))) &&
+ "Tree walk disagrees with dfs numbers!");
+#endif
+
if (DFSInfoValid)
return B->DominatedBy(A);
return dominatedBySlowTreeWalk(A, B);
}
- inline bool dominates(NodeT *A, NodeT *B) {
- if (A == B)
- return true;
-
- return dominates(getNode(A), getNode(B));
- }
-
+ bool dominates(const NodeT *A, const NodeT *B);
+
NodeT *getRoot() const {
assert(this->Roots.size() == 1 && "Should always have entry node!");
return this->Roots[0];
/// findNearestCommonDominator - Find nearest common dominator basic block
/// for basic block A and B. If there is no such block then return NULL.
NodeT *findNearestCommonDominator(NodeT *A, NodeT *B) {
-
- assert (!this->isPostDominator()
- && "This is not implemented for post dominators");
- assert (A->getParent() == B->getParent()
- && "Two blocks are not in same function");
-
- // If either A or B is a entry block then it is nearest common dominator.
- NodeT &Entry = A->getParent()->front();
- if (A == &Entry || B == &Entry)
- return &Entry;
+ assert(A->getParent() == B->getParent() &&
+ "Two blocks are not in same function");
+
+ // If either A or B is a entry block then it is nearest common dominator
+ // (for forward-dominators).
+ if (!this->isPostDominator()) {
+ NodeT &Entry = A->getParent()->front();
+ if (A == &Entry || B == &Entry)
+ return &Entry;
+ }
// If B dominates A then B is nearest common dominator.
if (dominates(B, A))
// Walk NodeB immediate dominators chain and find common dominator node.
DomTreeNodeBase<NodeT> *IDomB = NodeB->getIDom();
- while(IDomB) {
+ while (IDomB) {
if (NodeADoms.count(IDomB) != 0)
return IDomB->getBlock();
return NULL;
}
+ const NodeT *findNearestCommonDominator(const NodeT *A, const NodeT *B) {
+ // Cast away the const qualifiers here. This is ok since
+ // const is re-introduced on the return type.
+ return findNearestCommonDominator(const_cast<NodeT *>(A),
+ const_cast<NodeT *>(B));
+ }
+
//===--------------------------------------------------------------------===//
// API to update (Post)DominatorTree information based on modifications to
// the CFG...
/// addNewBlock - Add a new node to the dominator tree information. This
- /// creates a new node as a child of DomBB dominator node,linking it into
+ /// creates a new node as a child of DomBB dominator node,linking it into
/// the children list of the immediate dominator.
DomTreeNodeBase<NodeT> *addNewBlock(NodeT *BB, NodeT *DomBB) {
assert(getNode(BB) == 0 && "Block already in dominator tree!");
DomTreeNodeBase<NodeT> *IDomNode = getNode(DomBB);
assert(IDomNode && "Not immediate dominator specified for block!");
DFSInfoValid = false;
- return DomTreeNodes[BB] =
+ return DomTreeNodes[BB] =
IDomNode->addChild(new DomTreeNodeBase<NodeT>(BB, IDomNode));
}
changeImmediateDominator(getNode(BB), getNode(NewBB));
}
- /// eraseNode - Removes a node from the dominator tree. Block must not
- /// domiante any other blocks. Removes node from its immediate dominator's
+ /// eraseNode - Removes a node from the dominator tree. Block must not
+ /// dominate any other blocks. Removes node from its immediate dominator's
/// children list. Deletes dominator node associated with basic block BB.
void eraseNode(NodeT *BB) {
DomTreeNodeBase<NodeT> *Node = getNode(BB);
- assert (Node && "Removing node that isn't in dominator tree.");
- assert (Node->getChildren().empty() && "Node is not a leaf node.");
+ assert(Node && "Removing node that isn't in dominator tree.");
+ assert(Node->getChildren().empty() && "Node is not a leaf node.");
// Remove node from immediate dominator's children list.
DomTreeNodeBase<NodeT> *IDom = Node->getIDom();
assert(getNode(BB) && "Removing node that isn't in dominator tree.");
DomTreeNodes.erase(BB);
}
-
+
/// splitBlock - BB is split and now it has one successor. Update dominator
/// tree to reflect this change.
void splitBlock(NodeT* NewBB) {
/// print - Convert to human readable form
///
- virtual void print(std::ostream &o, const Module* ) const {
+ void print(raw_ostream &o) const {
o << "=============================--------------------------------\n";
if (this->isPostDominator())
o << "Inorder PostDominator Tree: ";
else
o << "Inorder Dominator Tree: ";
- if (this->DFSInfoValid)
+ if (!this->DFSInfoValid)
o << "DFSNumbers invalid: " << SlowQueries << " slow queries.";
o << "\n";
- PrintDomTree<NodeT>(getRootNode(), o, 1);
- }
-
- void print(std::ostream *OS, const Module* M = 0) const {
- if (OS) print(*OS, M);
+ // The postdom tree can have a null root if there are no returns.
+ if (getRootNode())
+ PrintDomTree<NodeT>(getRootNode(), o, 1);
}
-
- virtual void dump() {
- print(llvm::cerr);
- }
-
-protected:
- template<class GraphT>
- friend void Compress(DominatorTreeBase<typename GraphT::NodeType>& DT,
- typename GraphT::NodeType* VIn);
+protected:
template<class GraphT>
friend typename GraphT::NodeType* Eval(
DominatorTreeBase<typename GraphT::NodeType>& DT,
- typename GraphT::NodeType* V);
+ typename GraphT::NodeType* V,
+ unsigned LastLinked);
- template<class GraphT>
- friend void Link(DominatorTreeBase<typename GraphT::NodeType>& DT,
- unsigned DFSNumV, typename GraphT::NodeType* W,
- typename DominatorTreeBase<typename GraphT::NodeType>::InfoRec &WInfo);
-
template<class GraphT>
friend unsigned DFSPass(DominatorTreeBase<typename GraphT::NodeType>& DT,
typename GraphT::NodeType* V,
unsigned N);
-
+
template<class FuncT, class N>
friend void Calculate(DominatorTreeBase<typename GraphTraits<N>::NodeType>& DT,
FuncT& F);
-
+
/// updateDFSNumbers - Assign In and Out numbers to the nodes while walking
/// dominator tree in dfs order.
void updateDFSNumbers() {
SmallVector<std::pair<DomTreeNodeBase<NodeT>*,
typename DomTreeNodeBase<NodeT>::iterator>, 32> WorkStack;
- for (unsigned i = 0, e = this->Roots.size(); i != e; ++i) {
- DomTreeNodeBase<NodeT> *ThisRoot = getNode(this->Roots[i]);
- WorkStack.push_back(std::make_pair(ThisRoot, ThisRoot->begin()));
- ThisRoot->DFSNumIn = DFSNum++;
-
- while (!WorkStack.empty()) {
- DomTreeNodeBase<NodeT> *Node = WorkStack.back().first;
- typename DomTreeNodeBase<NodeT>::iterator ChildIt =
- WorkStack.back().second;
-
- // If we visited all of the children of this node, "recurse" back up the
- // stack setting the DFOutNum.
- if (ChildIt == Node->end()) {
- Node->DFSNumOut = DFSNum++;
- WorkStack.pop_back();
- } else {
- // Otherwise, recursively visit this child.
- DomTreeNodeBase<NodeT> *Child = *ChildIt;
- ++WorkStack.back().second;
-
- WorkStack.push_back(std::make_pair(Child, Child->begin()));
- Child->DFSNumIn = DFSNum++;
- }
+ DomTreeNodeBase<NodeT> *ThisRoot = getRootNode();
+
+ if (!ThisRoot)
+ return;
+
+ // Even in the case of multiple exits that form the post dominator root
+ // nodes, do not iterate over all exits, but start from the virtual root
+ // node. Otherwise bbs, that are not post dominated by any exit but by the
+ // virtual root node, will never be assigned a DFS number.
+ WorkStack.push_back(std::make_pair(ThisRoot, ThisRoot->begin()));
+ ThisRoot->DFSNumIn = DFSNum++;
+
+ while (!WorkStack.empty()) {
+ DomTreeNodeBase<NodeT> *Node = WorkStack.back().first;
+ typename DomTreeNodeBase<NodeT>::iterator ChildIt =
+ WorkStack.back().second;
+
+ // If we visited all of the children of this node, "recurse" back up the
+ // stack setting the DFOutNum.
+ if (ChildIt == Node->end()) {
+ Node->DFSNumOut = DFSNum++;
+ WorkStack.pop_back();
+ } else {
+ // Otherwise, recursively visit this child.
+ DomTreeNodeBase<NodeT> *Child = *ChildIt;
+ ++WorkStack.back().second;
+
+ WorkStack.push_back(std::make_pair(Child, Child->begin()));
+ Child->DFSNumIn = DFSNum++;
}
}
-
+
SlowQueries = 0;
DFSInfoValid = true;
}
-
+
DomTreeNodeBase<NodeT> *getNodeForBlock(NodeT *BB) {
- if (DomTreeNodeBase<NodeT> *BBNode = this->DomTreeNodes[BB])
- return BBNode;
+ if (DomTreeNodeBase<NodeT> *Node = getNode(BB))
+ return Node;
// Haven't calculated this node yet? Get or calculate the node for the
// immediate dominator.
NodeT *IDom = getIDom(BB);
- // skip all non root nodes that have no dominator
- if (!IDom && std::count(this->Roots.begin(), this->Roots.end(), BB) == 0)
- return NULL;
-
+ assert(IDom || this->DomTreeNodes[NULL]);
DomTreeNodeBase<NodeT> *IDomNode = getNodeForBlock(IDom);
- // skip all nodes that are dominated by a non root node that, by itself,
- // has no dominator.
- if (!IDomNode)
- return NULL;
-
// Add a new tree node for this BasicBlock, and link it as a child of
// IDomNode
DomTreeNodeBase<NodeT> *C = new DomTreeNodeBase<NodeT>(BB, IDomNode);
return this->DomTreeNodes[BB] = IDomNode->addChild(C);
}
-
+
inline NodeT *getIDom(NodeT *BB) const {
- typename DenseMap<NodeT*, NodeT*>::const_iterator I = IDoms.find(BB);
- return I != IDoms.end() ? I->second : 0;
+ return IDoms.lookup(BB);
}
-
+
inline void addRoot(NodeT* BB) {
this->Roots.push_back(BB);
}
-
+
public:
/// recalculate - compute a dominator tree for the given function
template<class FT>
void recalculate(FT& F) {
+ typedef GraphTraits<FT*> TraitsTy;
+ reset();
+ this->Vertex.push_back(0);
+
if (!this->IsPostDominators) {
- reset();
-
- // Initialize roots
- this->Roots.push_back(&F.front());
- this->IDoms[&F.front()] = 0;
- this->DomTreeNodes[&F.front()] = 0;
- this->Vertex.push_back(0);
-
+ // Initialize root
+ NodeT *entry = TraitsTy::getEntryNode(&F);
+ this->Roots.push_back(entry);
+ this->IDoms[entry] = 0;
+ this->DomTreeNodes[entry] = 0;
+
Calculate<FT, NodeT*>(*this, F);
-
- updateDFSNumbers();
} else {
- reset(); // Reset from the last time we were run...
-
// Initialize the roots list
- for (typename FT::iterator I = F.begin(), E = F.end(); I != E; ++I) {
- if (std::distance(GraphTraits<FT*>::child_begin(I),
- GraphTraits<FT*>::child_end(I)) == 0)
+ for (typename TraitsTy::nodes_iterator I = TraitsTy::nodes_begin(&F),
+ E = TraitsTy::nodes_end(&F); I != E; ++I) {
+ if (std::distance(TraitsTy::child_begin(I),
+ TraitsTy::child_end(I)) == 0)
addRoot(I);
// Prepopulate maps so that we don't get iterator invalidation issues later.
this->DomTreeNodes[I] = 0;
}
- this->Vertex.push_back(0);
-
Calculate<FT, Inverse<NodeT*> >(*this, F);
}
}
};
+// These two functions are declared out of line as a workaround for building
+// with old (< r147295) versions of clang because of pr11642.
+template<class NodeT>
+bool DominatorTreeBase<NodeT>::dominates(const NodeT *A, const NodeT *B) {
+ if (A == B)
+ return true;
+
+ // Cast away the const qualifiers here. This is ok since
+ // this function doesn't actually return the values returned
+ // from getNode.
+ return dominates(getNode(const_cast<NodeT *>(A)),
+ getNode(const_cast<NodeT *>(B)));
+}
+template<class NodeT>
+bool
+DominatorTreeBase<NodeT>::properlyDominates(const NodeT *A, const NodeT *B) {
+ if (A == B)
+ return false;
+
+ // Cast away the const qualifiers here. This is ok since
+ // this function doesn't actually return the values returned
+ // from getNode.
+ return dominates(getNode(const_cast<NodeT *>(A)),
+ getNode(const_cast<NodeT *>(B)));
+}
+
EXTERN_TEMPLATE_INSTANTIATION(class DominatorTreeBase<BasicBlock>);
+class BasicBlockEdge {
+ const BasicBlock *Start;
+ const BasicBlock *End;
+public:
+ BasicBlockEdge(const BasicBlock *Start_, const BasicBlock *End_) :
+ Start(Start_), End(End_) { }
+ const BasicBlock *getStart() const {
+ return Start;
+ }
+ const BasicBlock *getEnd() const {
+ return End;
+ }
+ bool isSingleEdge() const;
+};
+
//===-------------------------------------
/// DominatorTree Class - Concrete subclass of DominatorTreeBase that is used to
/// compute a normal dominator tree.
public:
static char ID; // Pass ID, replacement for typeid
DominatorTreeBase<BasicBlock>* DT;
-
- DominatorTree() : FunctionPass(intptr_t(&ID)) {
+
+ DominatorTree() : FunctionPass(ID) {
+ initializeDominatorTreePass(*PassRegistry::getPassRegistry());
DT = new DominatorTreeBase<BasicBlock>(false);
}
-
+
~DominatorTree() {
- DT->releaseMemory();
delete DT;
}
-
+
DominatorTreeBase<BasicBlock>& getBase() { return *DT; }
-
- /// getRoots - Return the root blocks of the current CFG. This may include
+
+ /// getRoots - Return the root blocks of the current CFG. This may include
/// multiple blocks if we are computing post dominators. For forward
/// dominators, this will always be a single block (the entry node).
///
inline const std::vector<BasicBlock*> &getRoots() const {
return DT->getRoots();
}
-
+
inline BasicBlock *getRoot() const {
return DT->getRoot();
}
-
+
inline DomTreeNode *getRootNode() const {
return DT->getRootNode();
}
-
+
+ /// compare - Return false if the other dominator tree matches this
+ /// dominator tree. Otherwise return true.
+ inline bool compare(DominatorTree &Other) const {
+ DomTreeNode *R = getRootNode();
+ DomTreeNode *OtherR = Other.getRootNode();
+
+ if (!R || !OtherR || R->getBlock() != OtherR->getBlock())
+ return true;
+
+ if (DT->compare(Other.getBase()))
+ return true;
+
+ return false;
+ }
+
virtual bool runOnFunction(Function &F);
-
+
+ virtual void verifyAnalysis() const;
+
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
}
-
- inline bool dominates(DomTreeNode* A, DomTreeNode* B) const {
+
+ inline bool dominates(const DomTreeNode* A, const DomTreeNode* B) const {
return DT->dominates(A, B);
}
-
- inline bool dominates(BasicBlock* A, BasicBlock* B) const {
+
+ inline bool dominates(const BasicBlock* A, const BasicBlock* B) const {
return DT->dominates(A, B);
}
-
- // dominates - Return true if A dominates B. This performs the
- // special checks necessary if A and B are in the same basic block.
- bool dominates(Instruction *A, Instruction *B) const {
- BasicBlock *BBA = A->getParent(), *BBB = B->getParent();
- if (BBA != BBB) return DT->dominates(BBA, BBB);
-
- // It is not possible to determine dominance between two PHI nodes
- // based on their ordering.
- if (isa<PHINode>(A) && isa<PHINode>(B))
- return false;
- // Loop through the basic block until we find A or B.
- BasicBlock::iterator I = BBA->begin();
- for (; &*I != A && &*I != B; ++I) /*empty*/;
+ // dominates - Return true if Def dominates a use in User. This performs
+ // the special checks necessary if Def and User are in the same basic block.
+ // Note that Def doesn't dominate a use in Def itself!
+ bool dominates(const Instruction *Def, const Use &U) const;
+ bool dominates(const Instruction *Def, const Instruction *User) const;
+ bool dominates(const Instruction *Def, const BasicBlock *BB) const;
+ bool dominates(const BasicBlockEdge &BBE, const Use &U) const;
+ bool dominates(const BasicBlockEdge &BBE, const BasicBlock *BB) const;
- //if(!DT.IsPostDominators) {
- // A dominates B if it is found first in the basic block.
- return &*I == A;
- //} else {
- // // A post-dominates B if B is found first in the basic block.
- // return &*I == B;
- //}
- }
-
- inline bool properlyDominates(const DomTreeNode* A, DomTreeNode* B) const {
+ bool properlyDominates(const DomTreeNode *A, const DomTreeNode *B) const {
return DT->properlyDominates(A, B);
}
-
- inline bool properlyDominates(BasicBlock* A, BasicBlock* B) const {
+
+ bool properlyDominates(const BasicBlock *A, const BasicBlock *B) const {
return DT->properlyDominates(A, B);
}
-
+
/// findNearestCommonDominator - Find nearest common dominator basic block
/// for basic block A and B. If there is no such block then return NULL.
inline BasicBlock *findNearestCommonDominator(BasicBlock *A, BasicBlock *B) {
return DT->findNearestCommonDominator(A, B);
}
-
+
+ inline const BasicBlock *findNearestCommonDominator(const BasicBlock *A,
+ const BasicBlock *B) {
+ return DT->findNearestCommonDominator(A, B);
+ }
+
inline DomTreeNode *operator[](BasicBlock *BB) const {
return DT->getNode(BB);
}
-
+
/// getNode - return the (Post)DominatorTree node for the specified basic
/// block. This is the same as using operator[] on this class.
///
inline DomTreeNode *getNode(BasicBlock *BB) const {
return DT->getNode(BB);
}
-
+
/// addNewBlock - Add a new node to the dominator tree information. This
- /// creates a new node as a child of DomBB dominator node,linking it into
+ /// creates a new node as a child of DomBB dominator node,linking it into
/// the children list of the immediate dominator.
inline DomTreeNode *addNewBlock(BasicBlock *BB, BasicBlock *DomBB) {
return DT->addNewBlock(BB, DomBB);
}
-
+
/// changeImmediateDominator - This method is used to update the dominator
/// tree information when a node's immediate dominator changes.
///
inline void changeImmediateDominator(BasicBlock *N, BasicBlock* NewIDom) {
DT->changeImmediateDominator(N, NewIDom);
}
-
+
inline void changeImmediateDominator(DomTreeNode *N, DomTreeNode* NewIDom) {
DT->changeImmediateDominator(N, NewIDom);
}
-
- /// eraseNode - Removes a node from the dominator tree. Block must not
- /// domiante any other blocks. Removes node from its immediate dominator's
+
+ /// eraseNode - Removes a node from the dominator tree. Block must not
+ /// dominate any other blocks. Removes node from its immediate dominator's
/// children list. Deletes dominator node associated with basic block BB.
inline void eraseNode(BasicBlock *BB) {
DT->eraseNode(BB);
}
-
+
/// splitBlock - BB is split and now it has one successor. Update dominator
/// tree to reflect this change.
inline void splitBlock(BasicBlock* NewBB) {
DT->splitBlock(NewBB);
}
-
-
- virtual void releaseMemory() {
- DT->releaseMemory();
+
+ bool isReachableFromEntry(const BasicBlock* A) const {
+ return DT->isReachableFromEntry(A);
}
-
- virtual void print(std::ostream &OS, const Module* M= 0) const {
- DT->print(OS, M);
+
+ bool isReachableFromEntry(const Use &U) const;
+
+
+ virtual void releaseMemory() {
+ DT->releaseMemory();
}
+
+ virtual void print(raw_ostream &OS, const Module* M= 0) const;
};
//===-------------------------------------
/// DominatorTree GraphTraits specialization so the DominatorTree can be
/// iterable by generic graph iterators.
///
-template <> struct GraphTraits<DomTreeNode *> {
+template <> struct GraphTraits<DomTreeNode*> {
typedef DomTreeNode NodeType;
typedef NodeType::iterator ChildIteratorType;
-
+
static NodeType *getEntryNode(NodeType *N) {
return N;
}
- static inline ChildIteratorType child_begin(NodeType* N) {
+ static inline ChildIteratorType child_begin(NodeType *N) {
return N->begin();
}
- static inline ChildIteratorType child_end(NodeType* N) {
+ static inline ChildIteratorType child_end(NodeType *N) {
return N->end();
}
-};
-
-template <> struct GraphTraits<DominatorTree*>
- : public GraphTraits<DomTreeNode *> {
- static NodeType *getEntryNode(DominatorTree *DT) {
- return DT->getRootNode();
- }
-};
-
-
-//===----------------------------------------------------------------------===//
-/// DominanceFrontierBase - Common base class for computing forward and inverse
-/// dominance frontiers for a function.
-///
-class DominanceFrontierBase : public FunctionPass {
-public:
- typedef std::set<BasicBlock*> DomSetType; // Dom set for a bb
- typedef std::map<BasicBlock*, DomSetType> DomSetMapType; // Dom set map
-protected:
- DomSetMapType Frontiers;
- std::vector<BasicBlock*> Roots;
- const bool IsPostDominators;
-
-public:
- DominanceFrontierBase(intptr_t ID, bool isPostDom)
- : FunctionPass(ID), IsPostDominators(isPostDom) {}
-
- /// getRoots - Return the root blocks of the current CFG. This may include
- /// multiple blocks if we are computing post dominators. For forward
- /// dominators, this will always be a single block (the entry node).
- ///
- inline const std::vector<BasicBlock*> &getRoots() const { return Roots; }
-
- /// isPostDominator - Returns true if analysis based of postdoms
- ///
- bool isPostDominator() const { return IsPostDominators; }
-
- virtual void releaseMemory() { Frontiers.clear(); }
-
- // Accessor interface:
- typedef DomSetMapType::iterator iterator;
- typedef DomSetMapType::const_iterator const_iterator;
- iterator begin() { return Frontiers.begin(); }
- const_iterator begin() const { return Frontiers.begin(); }
- iterator end() { return Frontiers.end(); }
- const_iterator end() const { return Frontiers.end(); }
- iterator find(BasicBlock *B) { return Frontiers.find(B); }
- const_iterator find(BasicBlock *B) const { return Frontiers.find(B); }
-
- void addBasicBlock(BasicBlock *BB, const DomSetType &frontier) {
- assert(find(BB) == end() && "Block already in DominanceFrontier!");
- Frontiers.insert(std::make_pair(BB, frontier));
- }
-
- /// removeBlock - Remove basic block BB's frontier.
- void removeBlock(BasicBlock *BB) {
- assert(find(BB) != end() && "Block is not in DominanceFrontier!");
- for (iterator I = begin(), E = end(); I != E; ++I)
- I->second.erase(BB);
- Frontiers.erase(BB);
- }
- void addToFrontier(iterator I, BasicBlock *Node) {
- assert(I != end() && "BB is not in DominanceFrontier!");
- I->second.insert(Node);
- }
+ typedef df_iterator<DomTreeNode*> nodes_iterator;
- void removeFromFrontier(iterator I, BasicBlock *Node) {
- assert(I != end() && "BB is not in DominanceFrontier!");
- assert(I->second.count(Node) && "Node is not in DominanceFrontier of BB");
- I->second.erase(Node);
+ static nodes_iterator nodes_begin(DomTreeNode *N) {
+ return df_begin(getEntryNode(N));
}
- /// print - Convert to human readable form
- ///
- virtual void print(std::ostream &OS, const Module* = 0) const;
- void print(std::ostream *OS, const Module* M = 0) const {
- if (OS) print(*OS, M);
+ static nodes_iterator nodes_end(DomTreeNode *N) {
+ return df_end(getEntryNode(N));
}
- virtual void dump();
};
-
-//===-------------------------------------
-/// DominanceFrontier Class - Concrete subclass of DominanceFrontierBase that is
-/// used to compute a forward dominator frontiers.
-///
-class DominanceFrontier : public DominanceFrontierBase {
-public:
- static char ID; // Pass ID, replacement for typeid
- DominanceFrontier() :
- DominanceFrontierBase(intptr_t(&ID), false) {}
-
- BasicBlock *getRoot() const {
- assert(Roots.size() == 1 && "Should always have entry node!");
- return Roots[0];
+template <> struct GraphTraits<DominatorTree*>
+ : public GraphTraits<DomTreeNode*> {
+ static NodeType *getEntryNode(DominatorTree *DT) {
+ return DT->getRootNode();
}
- virtual bool runOnFunction(Function &) {
- Frontiers.clear();
- DominatorTree &DT = getAnalysis<DominatorTree>();
- Roots = DT.getRoots();
- assert(Roots.size() == 1 && "Only one entry block for forward domfronts!");
- calculate(DT, DT[Roots[0]]);
- return false;
+ static nodes_iterator nodes_begin(DominatorTree *N) {
+ return df_begin(getEntryNode(N));
}
- virtual void getAnalysisUsage(AnalysisUsage &AU) const {
- AU.setPreservesAll();
- AU.addRequired<DominatorTree>();
- }
-
- /// splitBlock - BB is split and now it has one successor. Update dominance
- /// frontier to reflect this change.
- void splitBlock(BasicBlock *BB);
-
- /// BasicBlock BB's new dominator is NewBB. Update BB's dominance frontier
- /// to reflect this change.
- void changeImmediateDominator(BasicBlock *BB, BasicBlock *NewBB,
- DominatorTree *DT) {
- // NewBB is now dominating BB. Which means BB's dominance
- // frontier is now part of NewBB's dominance frontier. However, BB
- // itself is not member of NewBB's dominance frontier.
- DominanceFrontier::iterator NewDFI = find(NewBB);
- DominanceFrontier::iterator DFI = find(BB);
- DominanceFrontier::DomSetType BBSet = DFI->second;
- for (DominanceFrontier::DomSetType::iterator BBSetI = BBSet.begin(),
- BBSetE = BBSet.end(); BBSetI != BBSetE; ++BBSetI) {
- BasicBlock *DFMember = *BBSetI;
- // Insert only if NewBB dominates DFMember.
- if (!DT->dominates(NewBB, DFMember))
- NewDFI->second.insert(DFMember);
- }
- NewDFI->second.erase(BB);
+ static nodes_iterator nodes_end(DominatorTree *N) {
+ return df_end(getEntryNode(N));
}
-
-private:
- const DomSetType &calculate(const DominatorTree &DT,
- const DomTreeNode *Node);
};
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