//===----------------------------------------------------------------------===//
//
// This file defines the following classes:
-// 1. ImmediateDominators: Calculates and holds a mapping between BasicBlocks
-// and their immediate dominator.
-// 2. DominatorSet: Calculates the [reverse] dominator set for a function
-// 3. DominatorTree: Represent the ImmediateDominator as an explicit tree
-// structure.
-// 4. DominanceFrontier: Calculate and hold the dominance frontier for a
+// 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
-// ImmediateDominator mapping.
+// DominatorTree mapping.
//
//===----------------------------------------------------------------------===//
#include "llvm/Pass.h"
#include <set>
+#include "llvm/ADT/DenseMap.h"
namespace llvm {
protected:
std::vector<BasicBlock*> Roots;
const bool IsPostDominators;
-
- inline DominatorBase(bool isPostDom) : Roots(), IsPostDominators(isPostDom) {}
+ inline DominatorBase(intptr_t ID, bool isPostDom) :
+ FunctionPass(ID), Roots(), IsPostDominators(isPostDom) {}
public:
+
/// 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).
//===----------------------------------------------------------------------===//
-/// ImmediateDominators - Calculate the immediate dominator for each node in a
-/// function.
-///
-class ImmediateDominatorsBase : public DominatorBase {
-protected:
- std::map<BasicBlock*, BasicBlock*> IDoms;
+// DomTreeNode - Dominator Tree Node
+class DominatorTreeBase;
+class PostDominatorTree;
+class DomTreeNode {
+ BasicBlock *TheBB;
+ DomTreeNode *IDom;
+ std::vector<DomTreeNode*> Children;
+ int DFSNumIn, DFSNumOut;
+
+ friend class DominatorTreeBase;
+ friend class PostDominatorTree;
public:
- ImmediateDominatorsBase(bool isPostDom) : DominatorBase(isPostDom) {}
-
- virtual void releaseMemory() { IDoms.clear(); }
-
- // Accessor interface:
- typedef std::map<BasicBlock*, BasicBlock*> IDomMapType;
- typedef IDomMapType::const_iterator const_iterator;
- inline const_iterator begin() const { return IDoms.begin(); }
- inline const_iterator end() const { return IDoms.end(); }
- inline const_iterator find(BasicBlock* B) const { return IDoms.find(B);}
-
- /// operator[] - Return the idom for the specified basic block. The start
- /// node returns null, because it does not have an immediate dominator.
- ///
- inline BasicBlock *operator[](BasicBlock *BB) const {
- return get(BB);
- }
-
- /// get() - Synonym for operator[].
- ///
- inline BasicBlock *get(BasicBlock *BB) const {
- std::map<BasicBlock*, BasicBlock*>::const_iterator I = IDoms.find(BB);
- return I != IDoms.end() ? I->second : 0;
- }
-
- //===--------------------------------------------------------------------===//
- // API to update Immediate(Post)Dominators information based on modifications
- // to the CFG...
-
- /// addNewBlock - Add a new block to the CFG, with the specified immediate
- /// dominator.
- ///
- void addNewBlock(BasicBlock *BB, BasicBlock *IDom) {
- assert(get(BB) == 0 && "BasicBlock already in idom info!");
- IDoms[BB] = IDom;
- }
-
- /// setImmediateDominator - Update the immediate dominator information to
- /// change the current immediate dominator for the specified block to another
- /// block. This method requires that BB already have an IDom, otherwise just
- /// use addNewBlock.
- ///
- void setImmediateDominator(BasicBlock *BB, BasicBlock *NewIDom) {
- assert(IDoms.find(BB) != IDoms.end() && "BB doesn't have idom yet!");
- IDoms[BB] = NewIDom;
+ typedef std::vector<DomTreeNode*>::iterator iterator;
+ typedef std::vector<DomTreeNode*>::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(); }
+
+ BasicBlock *getBlock() const { return TheBB; }
+ DomTreeNode *getIDom() const { return IDom; }
+ const std::vector<DomTreeNode*> &getChildren() const { return Children; }
+
+ DomTreeNode(BasicBlock *BB, DomTreeNode *iDom)
+ : TheBB(BB), IDom(iDom), DFSNumIn(-1), DFSNumOut(-1) { }
+ DomTreeNode *addChild(DomTreeNode *C) { Children.push_back(C); return C; }
+ void setIDom(DomTreeNode *NewIDom);
+
+
+ /// getDFSNumIn/getDFSNumOut - These are an internal implementation detail, do
+ /// not call them.
+ unsigned getDFSNumIn() const { return DFSNumIn; }
+ unsigned getDFSNumOut() const { return DFSNumOut; }
+private:
+ // Return true if this node is dominated by other. Use this only if DFS info
+ // is valid.
+ bool DominatedBy(const DomTreeNode *other) const {
+ return this->DFSNumIn >= other->DFSNumIn &&
+ this->DFSNumOut <= other->DFSNumOut;
}
-
- /// print - Convert to human readable form
- ///
- virtual void print(std::ostream &OS, const Module* = 0) const;
};
-//===-------------------------------------
-/// ImmediateDominators Class - Concrete subclass of ImmediateDominatorsBase
-/// that is used to compute a normal immediate dominator set.
+//===----------------------------------------------------------------------===//
+/// DominatorTree - Calculate the immediate dominator tree for a function.
///
-struct ImmediateDominators : public ImmediateDominatorsBase {
- ImmediateDominators() : ImmediateDominatorsBase(false) {}
-
- BasicBlock *getRoot() const {
- assert(Roots.size() == 1 && "Should always have entry node!");
- return Roots[0];
- }
-
- virtual bool runOnFunction(Function &F);
-
- virtual void getAnalysisUsage(AnalysisUsage &AU) const {
- AU.setPreservesAll();
- }
+class DominatorTreeBase : public DominatorBase {
+protected:
+ void reset();
+ typedef DenseMap<BasicBlock*, DomTreeNode*> DomTreeNodeMapType;
+ DomTreeNodeMapType DomTreeNodes;
+ DomTreeNode *RootNode;
-private:
+ bool DFSInfoValid;
+ unsigned int SlowQueries;
+ // Information record used during immediate dominators computation.
struct InfoRec {
unsigned Semi;
unsigned Size;
std::vector<BasicBlock*> Bucket;
- InfoRec() : Semi(0), Size(0), Label(0), Parent(0), Child(0), Ancestor(0){}
+ InfoRec() : Semi(0), Size(0), Label(0), Parent(0), Child(0), Ancestor(0) {}
};
+ DenseMap<BasicBlock*, BasicBlock*> IDoms;
+
// Vertex - Map the DFS number to the BasicBlock*
std::vector<BasicBlock*> Vertex;
// Info - Collection of information used during the computation of idoms.
- std::map<BasicBlock*, InfoRec> Info;
-
- unsigned DFSPass(BasicBlock *V, InfoRec &VInfo, unsigned N);
- void Compress(BasicBlock *V, InfoRec &VInfo);
- BasicBlock *Eval(BasicBlock *v);
- void Link(BasicBlock *V, BasicBlock *W, InfoRec &WInfo);
-};
-
-
+ DenseMap<BasicBlock*, InfoRec> Info;
-//===----------------------------------------------------------------------===//
-/// DominatorSet - Maintain a set<BasicBlock*> for every basic block in a
-/// function, that represents the blocks that dominate the block. If the block
-/// is unreachable in this function, the set will be empty. This cannot happen
-/// for reachable code, because every block dominates at least itself.
-///
-struct DominatorSetBase : public DominatorBase {
- typedef std::set<BasicBlock*> DomSetType; // Dom set for a bb
- // Map of dom sets
- typedef std::map<BasicBlock*, DomSetType> DomSetMapType;
-protected:
- DomSetMapType Doms;
public:
- DominatorSetBase(bool isPostDom) : DominatorBase(isPostDom) {}
-
- virtual void releaseMemory() { Doms.clear(); }
-
- // Accessor interface:
- typedef DomSetMapType::const_iterator const_iterator;
- typedef DomSetMapType::iterator iterator;
- inline const_iterator begin() const { return Doms.begin(); }
- inline iterator begin() { return Doms.begin(); }
- inline const_iterator end() const { return Doms.end(); }
- inline iterator end() { return Doms.end(); }
- inline const_iterator find(BasicBlock* B) const { return Doms.find(B); }
- inline iterator find(BasicBlock* B) { return Doms.find(B); }
+ DominatorTreeBase(intptr_t ID, bool isPostDom)
+ : DominatorBase(ID, isPostDom), DFSInfoValid(false), SlowQueries(0) {}
+ ~DominatorTreeBase() { reset(); }
+ virtual void releaseMemory() { reset(); }
- /// getDominators - Return the set of basic blocks that dominate the specified
- /// block.
+ /// getNode - return the (Post)DominatorTree node for the specified basic
+ /// block. This is the same as using operator[] on this class.
///
- inline const DomSetType &getDominators(BasicBlock *BB) const {
- const_iterator I = find(BB);
- assert(I != end() && "BB not in function!");
- return I->second;
+ inline DomTreeNode *getNode(BasicBlock *BB) const {
+ DomTreeNodeMapType::const_iterator I = DomTreeNodes.find(BB);
+ return I != DomTreeNodes.end() ? I->second : 0;
}
- /// isReachable - Return true if the specified basicblock is reachable. If
- /// the block is reachable, we have dominator set information for it.
- ///
- bool isReachable(BasicBlock *BB) const {
- return !getDominators(BB).empty();
+ inline DomTreeNode *operator[](BasicBlock *BB) const {
+ return getNode(BB);
}
- /// dominates - Return true if A dominates B.
+ /// getRootNode - This returns the entry node for the CFG of the function. If
+ /// this tree represents the post-dominance relations for a function, however,
+ /// this root may be a node with the block == NULL. This is the case when
+ /// there are multiple exit nodes from a particular function. Consumers of
+ /// post-dominance information must be capable of dealing with this
+ /// possibility.
///
- inline bool dominates(BasicBlock *A, BasicBlock *B) const {
- return getDominators(B).count(A) != 0;
- }
+ DomTreeNode *getRootNode() { return RootNode; }
+ const DomTreeNode *getRootNode() const { return RootNode; }
- /// properlyDominates - Return true if A dominates B and A != B.
+ /// properlyDominates - Returns true iff this dominates N and this != N.
+ /// Note that this is not a constant time operation!
///
- bool properlyDominates(BasicBlock *A, BasicBlock *B) const {
- return dominates(A, B) && A != B;
+ bool properlyDominates(const DomTreeNode *A, DomTreeNode *B) const {
+ if (A == 0 || B == 0) return false;
+ return dominatedBySlowTreeWalk(A, B);
}
- /// print - Convert to human readable form
- ///
- virtual void print(std::ostream &OS, const Module* = 0) const;
-
- /// 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;
-
- //===--------------------------------------------------------------------===//
- // API to update (Post)DominatorSet information based on modifications to
- // the CFG...
-
- /// addBasicBlock - Call to update the dominator set with information about a
- /// new block that was inserted into the function.
- ///
- void addBasicBlock(BasicBlock *BB, const DomSetType &Dominators) {
- assert(find(BB) == end() && "Block already in DominatorSet!");
- Doms.insert(std::make_pair(BB, Dominators));
+ inline bool properlyDominates(BasicBlock *A, BasicBlock *B) {
+ return properlyDominates(getNode(A), getNode(B));
}
- /// addDominator - If a new block is inserted into the CFG, then method may be
- /// called to notify the blocks it dominates that it is in their set.
- ///
- void addDominator(BasicBlock *BB, BasicBlock *NewDominator) {
- iterator I = find(BB);
- assert(I != end() && "BB is not in DominatorSet!");
- I->second.insert(NewDominator);
+ bool dominatedBySlowTreeWalk(const DomTreeNode *A,
+ const DomTreeNode *B) const {
+ const DomTreeNode *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;
}
-};
-//===-------------------------------------
-/// DominatorSet Class - Concrete subclass of DominatorSetBase that is used to
-/// compute a normal dominator set.
-///
-struct DominatorSet : public DominatorSetBase {
- DominatorSet() : DominatorSetBase(false) {}
-
- virtual bool runOnFunction(Function &F);
-
- BasicBlock *getRoot() const {
- assert(Roots.size() == 1 && "Should always have entry node!");
- return Roots[0];
- }
-
- /// getAnalysisUsage - This simply provides a dominator set
+ /// isReachableFromEntry - Return true if A is dominated by the entry
+ /// block of the function containing it.
+ const bool isReachableFromEntry(BasicBlock* A);
+
+ /// dominates - Returns true iff A dominates B. Note that this is not a
+ /// constant time operation!
///
- virtual void getAnalysisUsage(AnalysisUsage &AU) const {
- AU.addRequired<ImmediateDominators>();
- AU.setPreservesAll();
- }
-
- // stub - dummy function, just ignore it
- static void stub();
-};
-
-
-//===----------------------------------------------------------------------===//
-/// DominatorTree - Calculate the immediate dominator tree for a function.
-///
-struct DominatorTreeBase : public DominatorBase {
- class Node;
-protected:
- std::map<BasicBlock*, Node*> Nodes;
- void reset();
- typedef std::map<BasicBlock*, Node*> NodeMapType;
-
- Node *RootNode;
-public:
- class Node {
- friend struct DominatorTree;
- friend struct PostDominatorTree;
- friend struct DominatorTreeBase;
- BasicBlock *TheBB;
- Node *IDom;
- std::vector<Node*> Children;
- public:
- typedef std::vector<Node*>::iterator iterator;
- typedef std::vector<Node*>::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(); }
-
- inline BasicBlock *getBlock() const { return TheBB; }
- inline Node *getIDom() const { return IDom; }
- inline const std::vector<Node*> &getChildren() const { return Children; }
-
- /// properlyDominates - Returns true iff this dominates N and this != N.
- /// Note that this is not a constant time operation!
- ///
- bool properlyDominates(const Node *N) const {
- const Node *IDom;
- if (this == 0 || N == 0) return false;
- while ((IDom = N->getIDom()) != 0 && IDom != this)
- N = IDom; // Walk up the tree
- return IDom != 0;
+ inline bool dominates(const DomTreeNode *A, DomTreeNode *B) {
+ if (B == A)
+ return true; // A node trivially dominates itself.
+
+ if (A == 0 || B == 0)
+ return false;
+
+ if (DFSInfoValid)
+ return B->DominatedBy(A);
+
+ // If we end up with too many slow queries, just update the
+ // DFS numbers on the theory that we are going to keep querying.
+ SlowQueries++;
+ if (SlowQueries > 32) {
+ updateDFSNumbers();
+ return B->DominatedBy(A);
}
- /// dominates - Returns true iff this dominates N. Note that this is not a
- /// constant time operation!
- ///
- inline bool dominates(const Node *N) const {
- if (N == this) return true; // A node trivially dominates itself.
- return properlyDominates(N);
- }
-
- private:
- inline Node(BasicBlock *BB, Node *iDom) : TheBB(BB), IDom(iDom) {}
- inline Node *addChild(Node *C) { Children.push_back(C); return C; }
-
- void setIDom(Node *NewIDom);
- };
-
-public:
- DominatorTreeBase(bool isPostDom) : DominatorBase(isPostDom) {}
- ~DominatorTreeBase() { reset(); }
-
- virtual void releaseMemory() { reset(); }
-
- /// getNode - return the (Post)DominatorTree node for the specified basic
- /// block. This is the same as using operator[] on this class.
- ///
- inline Node *getNode(BasicBlock *BB) const {
- NodeMapType::const_iterator i = Nodes.find(BB);
- return (i != Nodes.end()) ? i->second : 0;
+ return dominatedBySlowTreeWalk(A, B);
}
- inline Node *operator[](BasicBlock *BB) const {
- return getNode(BB);
+ inline bool dominates(BasicBlock *A, BasicBlock *B) {
+ if (A == B)
+ return true;
+
+ return dominates(getNode(A), getNode(B));
}
- /// getRootNode - This returns the entry node for the CFG of the function. If
- /// this tree represents the post-dominance relations for a function, however,
- /// this root may be a node with the block == NULL. This is the case when
- /// there are multiple exit nodes from a particular function. Consumers of
- /// post-dominance information must be capable of dealing with this
- /// possibility.
- ///
- Node *getRootNode() { return RootNode; }
- const Node *getRootNode() const { return RootNode; }
+ /// findNearestCommonDominator - Find nearest common dominator basic block
+ /// for basic block A and B. If there is no such block then return NULL.
+ BasicBlock *findNearestCommonDominator(BasicBlock *A, BasicBlock *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);
//===--------------------------------------------------------------------===//
// API to update (Post)DominatorTree information based on modifications to
// the CFG...
- /// createNewNode - Add a new node to the dominator tree information. This
- /// creates a new node as a child of IDomNode, linking it into the children
- /// list of the immediate dominator.
- ///
- Node *createNewNode(BasicBlock *BB, Node *IDomNode) {
+ /// 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
+ /// the children list of the immediate dominator.
+ DomTreeNode *addNewBlock(BasicBlock *BB, BasicBlock *DomBB) {
assert(getNode(BB) == 0 && "Block already in dominator tree!");
+ DomTreeNode *IDomNode = getNode(DomBB);
assert(IDomNode && "Not immediate dominator specified for block!");
- return Nodes[BB] = IDomNode->addChild(new Node(BB, IDomNode));
+ DFSInfoValid = false;
+ return DomTreeNodes[BB] =
+ IDomNode->addChild(new DomTreeNode(BB, IDomNode));
}
/// changeImmediateDominator - This method is used to update the dominator
/// tree information when a node's immediate dominator changes.
///
- void changeImmediateDominator(Node *N, Node *NewIDom) {
+ void changeImmediateDominator(DomTreeNode *N, DomTreeNode *NewIDom) {
assert(N && NewIDom && "Cannot change null node pointers!");
+ DFSInfoValid = false;
N->setIDom(NewIDom);
}
+ void changeImmediateDominator(BasicBlock *BB, BasicBlock *NewBB) {
+ 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
+ /// children list. Deletes dominator node associated with basic block BB.
+ void eraseNode(BasicBlock *BB);
+
+ /// removeNode - Removes a node from the dominator tree. Block must not
+ /// dominate any other blocks. Invalidates any node pointing to removed
+ /// block.
+ void removeNode(BasicBlock *BB) {
+ assert(getNode(BB) && "Removing node that isn't in dominator tree.");
+ DomTreeNodes.erase(BB);
+ }
+
/// 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);
+ }
+ virtual void dump();
+
+protected:
+ /// updateDFSNumbers - Assign In and Out numbers to the nodes while walking
+ /// dominator tree in dfs order.
+ void updateDFSNumbers();
+
+ DomTreeNode *getNodeForBlock(BasicBlock *BB);
+
+ inline BasicBlock *getIDom(BasicBlock *BB) const {
+ DenseMap<BasicBlock*, BasicBlock*>::const_iterator I = IDoms.find(BB);
+ return I != IDoms.end() ? I->second : 0;
+ }
};
-
//===-------------------------------------
/// DominatorTree Class - Concrete subclass of DominatorTreeBase that is used to
/// compute a normal dominator tree.
///
-struct DominatorTree : public DominatorTreeBase {
- DominatorTree() : DominatorTreeBase(false) {}
-
+class DominatorTree : public DominatorTreeBase {
+public:
+ static char ID; // Pass ID, replacement for typeid
+ DominatorTree() : DominatorTreeBase(intptr_t(&ID), false) {}
+
BasicBlock *getRoot() const {
assert(Roots.size() == 1 && "Should always have entry node!");
return Roots[0];
}
-
- virtual bool runOnFunction(Function &F) {
- reset(); // Reset from the last time we were run...
- ImmediateDominators &ID = getAnalysis<ImmediateDominators>();
- Roots = ID.getRoots();
- calculate(ID);
- return false;
- }
-
+
+ virtual bool runOnFunction(Function &F);
+
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
- AU.addRequired<ImmediateDominators>();
}
+
+ /// splitBlock
+ /// BB is split and now it has one successor. Update dominator tree to
+ /// reflect this change.
+ void splitBlock(BasicBlock *BB);
+
private:
- void calculate(const ImmediateDominators &ID);
- Node *getNodeForBlock(BasicBlock *BB);
+ friend void DTcalculate(DominatorTree& DT, Function& F);
+ friend void DTCompress(DominatorTree& DT, BasicBlock *VIn);
+ friend BasicBlock *DTEval(DominatorTree& DT, BasicBlock *v);
+ friend void DTLink(DominatorTree& DT, BasicBlock *V,
+ BasicBlock *W, InfoRec &WInfo);
+
+ unsigned DFSPass(BasicBlock *V, unsigned N);
};
//===-------------------------------------
/// DominatorTree GraphTraits specialization so the DominatorTree can be
/// iterable by generic graph iterators.
///
-template <> struct GraphTraits<DominatorTree::Node*> {
- typedef DominatorTree::Node NodeType;
+template <> struct GraphTraits<DomTreeNode*> {
+ typedef DomTreeNode NodeType;
typedef NodeType::iterator ChildIteratorType;
-
+
static NodeType *getEntryNode(NodeType *N) {
return N;
}
};
template <> struct GraphTraits<DominatorTree*>
- : public GraphTraits<DominatorTree::Node*> {
+ : public GraphTraits<DomTreeNode*> {
static NodeType *getEntryNode(DominatorTree *DT) {
return DT->getRootNode();
}
};
+
//===----------------------------------------------------------------------===//
-/// DominanceFrontier - Calculate the dominance frontiers for a function.
+/// DominanceFrontierBase - Common base class for computing forward and inverse
+/// dominance frontiers for a function.
///
-struct DominanceFrontierBase : public DominatorBase {
+class DominanceFrontierBase : public DominatorBase {
+public:
typedef std::set<BasicBlock*> DomSetType; // Dom set for a bb
typedef std::map<BasicBlock*, DomSetType> DomSetMapType; // Dom set map
protected:
DomSetMapType Frontiers;
public:
- DominanceFrontierBase(bool isPostDom) : DominatorBase(isPostDom) {}
+ DominanceFrontierBase(intptr_t ID, bool isPostDom)
+ : DominatorBase(ID, isPostDom) {}
virtual void releaseMemory() { Frontiers.clear(); }
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);
/// 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);
+ }
+ virtual void dump();
};
//===-------------------------------------
-/// DominatorTree Class - Concrete subclass of DominatorTreeBase that is used to
-/// compute a normal dominator tree.
+/// DominanceFrontier Class - Concrete subclass of DominanceFrontierBase that is
+/// used to compute a forward dominator frontiers.
///
-struct DominanceFrontier : public DominanceFrontierBase {
- DominanceFrontier() : DominanceFrontierBase(false) {}
+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!");
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);
+ }
+
private:
const DomSetType &calculate(const DominatorTree &DT,
- const DominatorTree::Node *Node);
+ const DomTreeNode *Node);
};
-// Make sure that any clients of this file link in Dominators.cpp
-static IncludeFile
-DOMINATORS_INCLUDE_FILE((void*)&DominatorSet::stub);
+
} // End llvm namespace
#endif
projects / oota-llvm.git / blobdiff