//
// This file defines the following classes:
// 1. DominatorTree: Represent dominators as an explicit tree structure.
-// 2. ETForest: Efficient data structure for dominance comparisons and
-// nearest-common-ancestor queries.
-// 3. DominanceFrontier: Calculate and hold the dominance frontier for a
+// 2. DominanceFrontier: Calculate and hold the dominance frontier for a
// function.
//
// These data structures are listed in increasing order of complexity. It
#ifndef LLVM_ANALYSIS_DOMINATORS_H
#define LLVM_ANALYSIS_DOMINATORS_H
-#include "llvm/Analysis/ET-Forest.h"
#include "llvm/Pass.h"
#include <set>
+#include "llvm/ADT/DenseMap.h"
namespace llvm {
//===----------------------------------------------------------------------===//
// 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:
typedef std::vector<DomTreeNode*>::iterator iterator;
typedef std::vector<DomTreeNode*>::const_iterator const_iterator;
const_iterator begin() const { return Children.begin(); }
const_iterator end() const { return Children.end(); }
- inline BasicBlock *getBlock() const { return TheBB; }
- inline DomTreeNode *getIDom() const { return IDom; }
- inline const std::vector<DomTreeNode*> &getChildren() const { return Children; }
+ BasicBlock *getBlock() const { return TheBB; }
+ DomTreeNode *getIDom() const { return IDom; }
+ const std::vector<DomTreeNode*> &getChildren() const { return Children; }
- inline DomTreeNode(BasicBlock *BB, DomTreeNode *iDom)
+ DomTreeNode(BasicBlock *BB, DomTreeNode *iDom)
: TheBB(BB), IDom(iDom), DFSNumIn(-1), DFSNumOut(-1) { }
- inline DomTreeNode *addChild(DomTreeNode *C) { Children.push_back(C); return C; }
+ DomTreeNode *addChild(DomTreeNode *C) { Children.push_back(C); return C; }
void setIDom(DomTreeNode *NewIDom);
- // Return true if this node is dominated by other. Use this only if DFS info is valid.
+
+ /// 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;
}
-
- /// assignDFSNumber - Assign In and Out numbers while walking dominator tree
- /// in dfs order.
- void assignDFSNumber(int num);
};
//===----------------------------------------------------------------------===//
/// DominatorTree - Calculate the immediate dominator tree for a function.
///
class DominatorTreeBase : public DominatorBase {
-
protected:
void reset();
- typedef std::map<BasicBlock*, DomTreeNode*> DomTreeNodeMapType;
+ typedef DenseMap<BasicBlock*, DomTreeNode*> DomTreeNodeMapType;
DomTreeNodeMapType DomTreeNodes;
DomTreeNode *RootNode;
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) {}
};
- std::map<BasicBlock*, BasicBlock*> IDoms;
+ 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;
+ DenseMap<BasicBlock*, InfoRec> Info;
- public:
+public:
DominatorTreeBase(intptr_t ID, bool isPostDom)
: DominatorBase(ID, isPostDom), DFSInfoValid(false), SlowQueries(0) {}
~DominatorTreeBase() { reset(); }
/// block. This is the same as using operator[] on this class.
///
inline DomTreeNode *getNode(BasicBlock *BB) const {
- DomTreeNodeMapType::const_iterator i = DomTreeNodes.find(BB);
- return (i != DomTreeNodes.end()) ? i->second : 0;
+ DomTreeNodeMapType::const_iterator I = DomTreeNodes.find(BB);
+ return I != DomTreeNodes.end() ? I->second : 0;
}
inline DomTreeNode *operator[](BasicBlock *BB) const {
return getNode(BB);
}
- /// getIDomBlock - return basic block BB's immediate dominator basic block.
- ///
- BasicBlock *getIDomBlock(BasicBlock *BB) {
- DomTreeNode *N = getNode(BB);
- assert (N && "Missing dominator tree node");
- DomTreeNode *I = N->getIDom();
- assert (N && "Missing immediate dominator");
- return I->getBlock();
- }
-
/// 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
const DomTreeNode *B) const {
const DomTreeNode *IDom;
if (A == 0 || B == 0) return false;
- while ((IDom = B->getIDom()) != 0 && IDom != A)
+ while ((IDom = B->getIDom()) != 0 && IDom != A && IDom != B)
B = IDom; // Walk up the tree
return IDom != 0;
}
- void updateDFSNumbers();
/// 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 this dominates N. Note that this is not a
+ /// dominates - Returns true iff A dominates B. Note that this is not a
/// constant time operation!
///
inline bool dominates(const DomTreeNode *A, DomTreeNode *B) {
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.
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();
};
//===-------------------------------------
class DominatorTree : public DominatorTreeBase {
public:
static char ID; // Pass ID, replacement for typeid
- DominatorTree() : DominatorTreeBase((intptr_t)&ID, false) {}
+ DominatorTree() : DominatorTreeBase(intptr_t(&ID), false) {}
BasicBlock *getRoot() const {
assert(Roots.size() == 1 && "Should always have entry node!");
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
}
+
+ /// splitBlock
+ /// BB is split and now it has one successor. Update dominator tree to
+ /// reflect this change.
+ void splitBlock(BasicBlock *BB);
private:
void calculate(Function& F);
DomTreeNode *getNodeForBlock(BasicBlock *BB);
- unsigned DFSPass(BasicBlock *V, InfoRec &VInfo, unsigned N);
+ unsigned DFSPass(BasicBlock *V, unsigned N);
void Compress(BasicBlock *V);
BasicBlock *Eval(BasicBlock *v);
void Link(BasicBlock *V, BasicBlock *W, InfoRec &WInfo);
inline BasicBlock *getIDom(BasicBlock *BB) const {
- std::map<BasicBlock*, BasicBlock*>::const_iterator I = IDoms.find(BB);
- return I != IDoms.end() ? I->second : 0;
- }
+ DenseMap<BasicBlock*, BasicBlock*>::const_iterator I = IDoms.find(BB);
+ return I != IDoms.end() ? I->second : 0;
+ }
};
//===-------------------------------------
};
-//===-------------------------------------
-/// ET-Forest Class - Class used to construct forwards and backwards
-/// ET-Forests
-///
-class ETForestBase : public DominatorBase {
-public:
- ETForestBase(intptr_t ID, bool isPostDom)
- : DominatorBase(ID, isPostDom), Nodes(),
- DFSInfoValid(false), SlowQueries(0) {}
-
- virtual void releaseMemory() { reset(); }
-
- typedef std::map<BasicBlock*, ETNode*> ETMapType;
-
- // FIXME : There is no need to make this interface public.
- // Fix predicate simplifier.
- void updateDFSNumbers();
-
- /// dominates - Return true if A dominates B.
- ///
- inline bool dominates(BasicBlock *A, BasicBlock *B) {
- if (A == B)
- return true;
-
- ETNode *NodeA = getNode(A);
- ETNode *NodeB = getNode(B);
-
- if (DFSInfoValid)
- return NodeB->DominatedBy(NodeA);
- else {
- // 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 NodeB->DominatedBy(NodeA);
- }
- return NodeB->DominatedBySlow(NodeA);
- }
- }
-
- // 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);
-
- /// properlyDominates - Return true if A dominates B and A != B.
- ///
- bool properlyDominates(BasicBlock *A, BasicBlock *B) {
- return dominates(A, B) && A != B;
- }
-
- /// isReachableFromEntry - Return true if A is dominated by the entry
- /// block of the function containing it.
- const bool isReachableFromEntry(BasicBlock* A);
-
- /// Return the nearest common dominator of A and B.
- BasicBlock *nearestCommonDominator(BasicBlock *A, BasicBlock *B) const {
- ETNode *NodeA = getNode(A);
- ETNode *NodeB = getNode(B);
-
- ETNode *Common = NodeA->NCA(NodeB);
- if (!Common)
- return NULL;
- return Common->getData<BasicBlock>();
- }
-
- /// Return the immediate dominator of A.
- BasicBlock *getIDom(BasicBlock *A) const {
- ETNode *NodeA = getNode(A);
- if (!NodeA) return 0;
- const ETNode *idom = NodeA->getFather();
- return idom ? idom->getData<BasicBlock>() : 0;
- }
-
- void getETNodeChildren(BasicBlock *A, std::vector<BasicBlock*>& children) const {
- ETNode *NodeA = getNode(A);
- if (!NodeA) return;
- const ETNode* son = NodeA->getSon();
-
- if (!son) return;
- children.push_back(son->getData<BasicBlock>());
-
- const ETNode* brother = son->getBrother();
- while (brother != son) {
- children.push_back(brother->getData<BasicBlock>());
- brother = brother->getBrother();
- }
- }
-
- virtual void getAnalysisUsage(AnalysisUsage &AU) const {
- AU.setPreservesAll();
- AU.addRequired<DominatorTree>();
- }
- //===--------------------------------------------------------------------===//
- // API to update Forest 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);
-
- /// setImmediateDominator - Update the immediate dominator information to
- /// change the current immediate dominator for the specified block
- /// to another block. This method requires that BB for NewIDom
- /// already have an ETNode, otherwise just use addNewBlock.
- ///
- void setImmediateDominator(BasicBlock *BB, BasicBlock *NewIDom);
- /// 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:
- /// getNode - return the (Post)DominatorTree node for the specified basic
- /// block. This is the same as using operator[] on this class.
- ///
- inline ETNode *getNode(BasicBlock *BB) const {
- ETMapType::const_iterator i = Nodes.find(BB);
- return (i != Nodes.end()) ? i->second : 0;
- }
-
- inline ETNode *operator[](BasicBlock *BB) const {
- return getNode(BB);
- }
-
- void reset();
- ETMapType Nodes;
- bool DFSInfoValid;
- unsigned int SlowQueries;
-
-};
-
-//==-------------------------------------
-/// ETForest Class - Concrete subclass of ETForestBase that is used to
-/// compute a forwards ET-Forest.
-
-class ETForest : public ETForestBase {
-public:
- static char ID; // Pass identification, replacement for typeid
-
- ETForest() : ETForestBase((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...
- DominatorTree &DT = getAnalysis<DominatorTree>();
- Roots = DT.getRoots();
- calculate(DT);
- return false;
- }
-
- void calculate(const DominatorTree &DT);
- // FIXME : There is no need to make getNodeForBlock public. Fix
- // predicate simplifier.
- ETNode *getNodeForBlock(BasicBlock *BB);
-};
-
//===----------------------------------------------------------------------===//
/// DominanceFrontierBase - Common base class for computing forward and inverse
/// dominance frontiers for a function.
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);
public:
static char ID; // Pass ID, replacement for typeid
DominanceFrontier() :
- DominanceFrontierBase((intptr_t)& ID, false) {}
+ DominanceFrontierBase(intptr_t(&ID), false) {}
BasicBlock *getRoot() const {
assert(Roots.size() == 1 && "Should always have entry node!");
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 DomTreeNode *Node);
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