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314 lines
11 KiB
C++
314 lines
11 KiB
C++
//===- llvm/Analysis/Dominators.h - Dominator Info Calculation ---*- C++ -*--=//
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//
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// This file defines the following classes:
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// 1. DominatorSet: Calculates the [reverse] dominator set for a method
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// 2. ImmediateDominators: Calculates and holds a mapping between BasicBlocks
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// and their immediate dominator.
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// 3. DominatorTree: Represent the ImmediateDominator as an explicit tree
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// structure.
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// 4. DominanceFrontier: Calculate and hold the dominance frontier for a
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// method.
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//
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// These data structures are listed in increasing order of complexity. It
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// takes longer to calculate the dominator frontier, for example, than the
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// ImmediateDominator mapping.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_DOMINATORS_H
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#define LLVM_DOMINATORS_H
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#include "llvm/Pass.h"
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#include <set>
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namespace cfg {
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//===----------------------------------------------------------------------===//
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//
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// DominatorBase - Base class that other, more interesting dominator analyses
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// inherit from.
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//
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class DominatorBase : public MethodPass {
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protected:
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BasicBlock *Root;
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const bool IsPostDominators;
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inline DominatorBase(bool isPostDom) : Root(0), IsPostDominators(isPostDom) {}
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public:
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inline const BasicBlock *getRoot() const { return Root; }
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inline BasicBlock *getRoot() { return Root; }
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// Returns true if analysis based of postdoms
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bool isPostDominator() const { return IsPostDominators; }
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};
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//===----------------------------------------------------------------------===//
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//
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// DominatorSet - Maintain a set<const BasicBlock*> for every basic block in a
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// method, that represents the blocks that dominate the block.
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//
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class DominatorSet : public DominatorBase {
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public:
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typedef std::set<const BasicBlock*> DomSetType; // Dom set for a bb
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// Map of dom sets
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typedef std::map<const BasicBlock*, DomSetType> DomSetMapType;
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private:
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DomSetMapType Doms;
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void calcForwardDominatorSet(Method *M);
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void calcPostDominatorSet(Method *M);
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public:
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// DominatorSet ctor - Build either the dominator set or the post-dominator
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// set for a method...
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//
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static AnalysisID ID; // Build dominator set
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static AnalysisID PostDomID; // Build postdominator set
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DominatorSet(AnalysisID id) : DominatorBase(id == PostDomID) {}
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virtual bool runOnMethod(Method *M);
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// Accessor interface:
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typedef DomSetMapType::const_iterator const_iterator;
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typedef DomSetMapType::iterator iterator;
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inline const_iterator begin() const { return Doms.begin(); }
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inline iterator begin() { return Doms.begin(); }
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inline const_iterator end() const { return Doms.end(); }
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inline iterator end() { return Doms.end(); }
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inline const_iterator find(const BasicBlock* B) const { return Doms.find(B); }
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inline iterator find( BasicBlock* B) { return Doms.find(B); }
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// getDominators - Return the set of basic blocks that dominate the specified
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// block.
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//
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inline const DomSetType &getDominators(const BasicBlock *BB) const {
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const_iterator I = find(BB);
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assert(I != end() && "BB not in method!");
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return I->second;
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}
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// dominates - Return true if A dominates B.
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//
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inline bool dominates(const BasicBlock *A, const BasicBlock *B) const {
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return getDominators(B).count(A) != 0;
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}
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// getAnalysisUsageInfo - This obviously provides a dominator set, but it also
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// uses the UnifyMethodExitNode pass if building post-dominators
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//
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virtual void getAnalysisUsageInfo(Pass::AnalysisSet &Requires,
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Pass::AnalysisSet &Destroyed,
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Pass::AnalysisSet &Provided);
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};
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//===----------------------------------------------------------------------===//
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//
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// ImmediateDominators - Calculate the immediate dominator for each node in a
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// method.
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//
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class ImmediateDominators : public DominatorBase {
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std::map<const BasicBlock*, const BasicBlock*> IDoms;
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void calcIDoms(const DominatorSet &DS);
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public:
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// ImmediateDominators ctor - Calculate the idom or post-idom mapping,
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// for a method...
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//
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static AnalysisID ID; // Build immediate dominators
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static AnalysisID PostDomID; // Build immediate postdominators
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ImmediateDominators(AnalysisID id) : DominatorBase(id == PostDomID) {}
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virtual bool runOnMethod(Method *M) {
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IDoms.clear(); // Reset from the last time we were run...
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DominatorSet *DS;
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if (isPostDominator())
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DS = &getAnalysis<DominatorSet>(DominatorSet::PostDomID);
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else
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DS = &getAnalysis<DominatorSet>();
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Root = DS->getRoot();
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calcIDoms(*DS); // Can be used to make rev-idoms
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return false;
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}
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// Accessor interface:
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typedef std::map<const BasicBlock*, const BasicBlock*> IDomMapType;
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typedef IDomMapType::const_iterator const_iterator;
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inline const_iterator begin() const { return IDoms.begin(); }
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inline const_iterator end() const { return IDoms.end(); }
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inline const_iterator find(const BasicBlock* B) const { return IDoms.find(B);}
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// operator[] - Return the idom for the specified basic block. The start
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// node returns null, because it does not have an immediate dominator.
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//
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inline const BasicBlock *operator[](const BasicBlock *BB) const {
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std::map<const BasicBlock*, const BasicBlock*>::const_iterator I =
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IDoms.find(BB);
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return I != IDoms.end() ? I->second : 0;
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}
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// getAnalysisUsageInfo - This obviously provides a dominator tree, but it
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// can only do so with the input of dominator sets
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//
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virtual void getAnalysisUsageInfo(Pass::AnalysisSet &Requires,
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Pass::AnalysisSet &Destroyed,
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Pass::AnalysisSet &Provided) {
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if (isPostDominator()) {
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Requires.push_back(DominatorSet::PostDomID);
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Provided.push_back(PostDomID);
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} else {
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Requires.push_back(DominatorSet::ID);
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Provided.push_back(ID);
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}
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}
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};
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//===----------------------------------------------------------------------===//
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//
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// DominatorTree - Calculate the immediate dominator tree for a method.
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//
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class DominatorTree : public DominatorBase {
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class Node2;
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public:
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typedef Node2 Node;
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private:
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std::map<const BasicBlock*, Node*> Nodes;
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void calculate(const DominatorSet &DS);
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void reset();
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typedef std::map<const BasicBlock*, Node*> NodeMapType;
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public:
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class Node2 : public std::vector<Node*> {
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friend class DominatorTree;
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const BasicBlock *TheNode;
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Node2 * const IDom;
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public:
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inline const BasicBlock *getNode() const { return TheNode; }
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inline Node2 *getIDom() const { return IDom; }
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inline const std::vector<Node*> &getChildren() const { return *this; }
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// dominates - Returns true iff this dominates N. Note that this is not a
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// constant time operation!
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inline bool dominates(const Node2 *N) const {
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const Node2 *IDom;
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while ((IDom = N->getIDom()) != 0 && IDom != this)
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N = IDom; // Walk up the tree
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return IDom != 0;
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}
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private:
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inline Node2(const BasicBlock *node, Node *iDom)
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: TheNode(node), IDom(iDom) {}
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inline Node2 *addChild(Node *C) { push_back(C); return C; }
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};
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public:
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// DominatorTree ctor - Compute a dominator tree, given various amounts of
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// previous knowledge...
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static AnalysisID ID; // Build dominator tree
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static AnalysisID PostDomID; // Build postdominator tree
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DominatorTree(AnalysisID id) : DominatorBase(id == PostDomID) {}
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~DominatorTree() { reset(); }
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virtual bool runOnMethod(Method *M) {
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reset();
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DominatorSet *DS;
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if (isPostDominator())
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DS = &getAnalysis<DominatorSet>(DominatorSet::PostDomID);
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else
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DS = &getAnalysis<DominatorSet>();
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Root = DS->getRoot();
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calculate(*DS); // Can be used to make rev-idoms
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return false;
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}
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inline const Node *operator[](const BasicBlock *BB) const {
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NodeMapType::const_iterator i = Nodes.find(BB);
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return (i != Nodes.end()) ? i->second : 0;
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}
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// getAnalysisUsageInfo - This obviously provides a dominator tree, but it
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// uses dominator sets
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//
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virtual void getAnalysisUsageInfo(Pass::AnalysisSet &Requires,
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Pass::AnalysisSet &Destroyed,
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Pass::AnalysisSet &Provided) {
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if (isPostDominator()) {
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Requires.push_back(DominatorSet::PostDomID);
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Provided.push_back(PostDomID);
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} else {
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Requires.push_back(DominatorSet::ID);
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Provided.push_back(ID);
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}
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}
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};
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//===----------------------------------------------------------------------===//
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//
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// DominanceFrontier - Calculate the dominance frontiers for a method.
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//
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class DominanceFrontier : public DominatorBase {
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public:
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typedef std::set<const BasicBlock*> DomSetType; // Dom set for a bb
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typedef std::map<const BasicBlock*, DomSetType> DomSetMapType; // Dom set map
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private:
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DomSetMapType Frontiers;
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const DomSetType &calcDomFrontier(const DominatorTree &DT,
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const DominatorTree::Node *Node);
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const DomSetType &calcPostDomFrontier(const DominatorTree &DT,
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const DominatorTree::Node *Node);
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public:
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// DominatorFrontier ctor - Compute dominator frontiers for a method
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//
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static AnalysisID ID; // Build dominator frontier
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static AnalysisID PostDomID; // Build postdominator frontier
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DominanceFrontier(AnalysisID id) : DominatorBase(id == PostDomID) {}
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virtual bool runOnMethod(Method *M) {
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Frontiers.clear();
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DominatorTree *DT;
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if (isPostDominator())
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DT = &getAnalysis<DominatorTree>(DominatorTree::PostDomID);
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else
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DT = &getAnalysis<DominatorTree>();
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Root = DT->getRoot();
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if (isPostDominator())
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calcPostDomFrontier(*DT, (*DT)[Root]);
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else
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calcDomFrontier(*DT, (*DT)[Root]);
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return false;
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}
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// Accessor interface:
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typedef DomSetMapType::const_iterator const_iterator;
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inline const_iterator begin() const { return Frontiers.begin(); }
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inline const_iterator end() const { return Frontiers.end(); }
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inline const_iterator find(const BasicBlock* B) const { return Frontiers.find(B); }
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// getAnalysisUsageInfo - This obviously provides a dominator tree, but it
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// uses dominator sets
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//
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virtual void getAnalysisUsageInfo(Pass::AnalysisSet &Requires,
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Pass::AnalysisSet &Destroyed,
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Pass::AnalysisSet &Provided) {
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if (isPostDominator()) {
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Requires.push_back(DominatorTree::PostDomID);
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Provided.push_back(PostDomID);
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} else {
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Requires.push_back(DominatorTree::ID);
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Provided.push_back(ID);
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}
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}
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};
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} // End namespace cfg
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#endif
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