Add new anaysis routines for building dominator related information

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/Analysis/Dominators.h b/include/llvm/Analysis/Dominators.h
new file mode 100644 (file)
index 0000000..5fd9026
--- /dev/null
+++ b/include/llvm/Analysis/Dominators.h
@@ -0,0 +1,190 @@
+//===- llvm/Analysis/DominatorSet.h - Dominator Set Calculation --*- C++ -*--=//
+//
+// This file defines the following classes:
+//  1. DominatorSet: Calculates the [reverse] dominator set for a method
+//  2. ImmediateDominators: Calculates and holds the immediate dominator tree
+//     for a method.
+// 
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_DOMINATOR_SET_H
+#define LLVM_DOMINATOR_SET_H
+
+#include <set>
+#include <map>
+#include <vector>
+class Method;
+class BasicBlock;
+
+namespace cfg {
+
+//===----------------------------------------------------------------------===//
+//
+// DominatorSet - Maintain a set<const BasicBlock*> for every basic block in a
+// method, that represents the blocks that dominate the block.
+//
+class DominatorSet {
+public:
+  typedef set<const BasicBlock*>              DomSetType;    // Dom set for a bb
+  typedef map<const BasicBlock *, DomSetType> DomSetMapType; // Map of dom sets
+private:
+  DomSetMapType Doms;
+  const BasicBlock *Root;
+public:
+  // DominatorSet ctor - Build either the dominator set or the post-dominator
+  // set for a method...
+  //
+  DominatorSet(const Method *M, bool PostDomSet = false);
+
+  // Accessor interface:
+  typedef DomSetMapType::const_iterator const_iterator;
+  inline const_iterator begin() const { return Doms.begin(); }
+  inline const_iterator end()   const { return Doms.end(); }
+  inline const_iterator find(const BasicBlock* B) const { return Doms.find(B); }
+  inline const BasicBlock *getRoot() const { return Root; }
+
+  // getDominators - Return the set of basic blocks that dominate the specified
+  // block.
+  //
+  inline const DomSetType &getDominators(const BasicBlock *BB) const {
+    const_iterator I = find(BB);
+    assert(I != end() && "BB not in method!");
+    return I->second;
+  }
+
+  // dominates - Return true if A dominates B.
+  //
+  inline bool dominates(const BasicBlock *A, const BasicBlock *B) const {
+    return getDominators(B).count(A) != 0;
+  }
+};
+
+
+//===----------------------------------------------------------------------===//
+//
+// ImmediateDominators - Calculate the immediate dominator for each node in a
+// method.
+//
+class ImmediateDominators {
+  map<const BasicBlock*, const BasicBlock*> IDoms;
+  const BasicBlock *Root;
+  void calcIDoms(const DominatorSet &DS);
+public:
+
+  // ImmediateDominators ctor - Calculate the idom mapping, for a method, or
+  // from a dominator set calculated for something else...
+  //
+  inline ImmediateDominators(const DominatorSet &DS) : Root(DS.getRoot()) {
+    calcIDoms(DS);                         // Can be used to make rev-idoms
+  }
+
+  // Accessor interface:
+  typedef map<const BasicBlock*, const 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(const BasicBlock* B) const { return IDoms.find(B);}
+  inline const BasicBlock *getRoot() const { return Root; }
+
+  // operator[] - Return the idom for the specified basic block.  The start
+  // node returns null, because it does not have an immediate dominator.
+  //
+  inline const BasicBlock *operator[](const BasicBlock *BB) const {
+    map<const BasicBlock*, const BasicBlock*>::const_iterator I = 
+      IDoms.find(BB);
+    return I != IDoms.end() ? I->second : 0;
+  }
+};
+
+
+//===----------------------------------------------------------------------===//
+//
+// DominatorTree - Calculate the immediate dominator tree for a method.
+//
+class DominatorTree {
+  class Node;
+  const BasicBlock *Root;
+  map<const BasicBlock*, Node*> Nodes;
+  void calculate(const DominatorSet &DS);
+  typedef map<const BasicBlock*, Node*> NodeMapType;
+public:
+  class Node : public vector<Node*> {
+    friend class DominatorTree;
+    const BasicBlock *TheNode;
+    Node * const IDom;
+  public:
+    inline const BasicBlock *getNode() const { return TheNode; }
+    inline Node *getIDom() const { return IDom; }
+    inline const vector<Node*> &getChildren() const { return *this; }
+
+    // dominates - Returns true iff this dominates N.  Note that this is not a 
+    // constant time operation!
+    inline bool dominates(const Node *N) const {
+      const Node *IDom;
+      while ((IDom = N->getIDom()) != 0 && IDom != this)
+       N = IDom;   // Walk up the tree
+      return IDom != 0;
+    }
+
+  private:
+    inline Node(const BasicBlock *node, Node *iDom) 
+      : TheNode(node), IDom(iDom) {}
+    inline Node *addChild(Node *C) { push_back(C); return C; }
+  };
+
+public:
+  // DominatorTree ctors - Compute a dominator tree, given various amounts of
+  // previous knowledge...
+  //inline DominatorTree(const Method *M) { calculate(DominatorSet(M)); }
+  inline DominatorTree(const DominatorSet &DS) : Root(DS.getRoot()) { 
+    calculate(DS); 
+  }
+
+  DominatorTree(const ImmediateDominators &IDoms);
+  ~DominatorTree();
+
+  inline const BasicBlock *getRoot() const { return Root; }
+  inline const Node *operator[](const BasicBlock *BB) const {
+    NodeMapType::const_iterator i = Nodes.find(BB);
+    return (i != Nodes.end()) ? i->second : 0;
+  }
+};
+
+
+//===----------------------------------------------------------------------===//
+//
+// DominanceFrontier - Calculate the dominance frontiers for a method.
+//
+class DominanceFrontier {
+  typedef set<const BasicBlock*>              DomSetType;    // Dom set for a bb
+  typedef map<const BasicBlock *, DomSetType> DomSetMapType; // Map of dom sets
+private:
+  DomSetMapType Frontiers;
+  const BasicBlock *Root;
+  const DomSetType &calcDomFrontier(const DominatorTree &DT,
+                                   const DominatorTree::Node *Node);
+public:
+  DominanceFrontier(const DominatorSet &DS) : Root(DS.getRoot()) {
+    const DominatorTree DT(DS);
+    calcDomFrontier(DT, DT[Root]);
+  }    
+  DominanceFrontier(const ImmediateDominators &ID) : Root(ID.getRoot()) {
+    const DominatorTree DT(ID);
+    calcDomFrontier(DT, DT[Root]);
+  }
+  DominanceFrontier(const DominatorTree &DT) : Root(DT.getRoot()) {
+    calcDomFrontier(DT, DT[Root]);
+  }
+
+  // Accessor interface:
+  typedef DomSetMapType::const_iterator const_iterator;
+  inline const_iterator begin() const { return Frontiers.begin(); }
+  inline const_iterator end()   const { return Frontiers.end(); }
+  inline const_iterator find(const BasicBlock* B) const { return Frontiers.find(B);}
+  inline const BasicBlock *getRoot() const { return Root; }
+
+};
+
+} // End namespace cfg
+
+#endif