2014-01-13 10:52:56 +00:00
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//===- GenericDomTree.h - Generic dominator trees for graphs ----*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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/// \file
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///
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/// This file defines a set of templates that efficiently compute a dominator
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/// tree over a generic graph. This is used typically in LLVM for fast
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/// dominance queries on the CFG, but is fully generic w.r.t. the underlying
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/// graph types.
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///
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//===----------------------------------------------------------------------===//
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2014-08-13 16:26:38 +00:00
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#ifndef LLVM_SUPPORT_GENERICDOMTREE_H
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#define LLVM_SUPPORT_GENERICDOMTREE_H
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2014-01-13 10:52:56 +00:00
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#include "llvm/ADT/DenseMap.h"
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#include "llvm/ADT/DepthFirstIterator.h"
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#include "llvm/ADT/GraphTraits.h"
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#include "llvm/ADT/SmallPtrSet.h"
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/Support/Compiler.h"
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#include "llvm/Support/raw_ostream.h"
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#include <algorithm>
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namespace llvm {
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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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template <class NodeT>
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class DominatorBase {
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protected:
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std::vector<NodeT*> Roots;
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const bool IsPostDominators;
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inline explicit DominatorBase(bool isPostDom) :
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Roots(), IsPostDominators(isPostDom) {}
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public:
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/// getRoots - Return the root blocks of the current CFG. This may include
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/// multiple blocks if we are computing post dominators. For forward
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/// dominators, this will always be a single block (the entry node).
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///
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inline const std::vector<NodeT*> &getRoots() const { return Roots; }
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/// isPostDominator - Returns true if analysis based of postdoms
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///
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bool isPostDominator() const { return IsPostDominators; }
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};
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//===----------------------------------------------------------------------===//
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// DomTreeNodeBase - Dominator Tree Node
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template<class NodeT> class DominatorTreeBase;
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struct PostDominatorTree;
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template <class NodeT>
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class DomTreeNodeBase {
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NodeT *TheBB;
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DomTreeNodeBase<NodeT> *IDom;
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std::vector<DomTreeNodeBase<NodeT> *> Children;
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2014-01-13 11:58:34 +00:00
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mutable int DFSNumIn, DFSNumOut;
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2014-01-13 10:52:56 +00:00
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template<class N> friend class DominatorTreeBase;
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friend struct PostDominatorTree;
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public:
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typedef typename std::vector<DomTreeNodeBase<NodeT> *>::iterator iterator;
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typedef typename std::vector<DomTreeNodeBase<NodeT> *>::const_iterator
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const_iterator;
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iterator begin() { return Children.begin(); }
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iterator end() { return Children.end(); }
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const_iterator begin() const { return Children.begin(); }
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const_iterator end() const { return Children.end(); }
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NodeT *getBlock() const { return TheBB; }
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DomTreeNodeBase<NodeT> *getIDom() const { return IDom; }
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const std::vector<DomTreeNodeBase<NodeT>*> &getChildren() const {
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return Children;
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}
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DomTreeNodeBase(NodeT *BB, DomTreeNodeBase<NodeT> *iDom)
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: TheBB(BB), IDom(iDom), DFSNumIn(-1), DFSNumOut(-1) { }
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DomTreeNodeBase<NodeT> *addChild(DomTreeNodeBase<NodeT> *C) {
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Children.push_back(C);
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return C;
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}
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size_t getNumChildren() const {
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return Children.size();
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}
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void clearAllChildren() {
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Children.clear();
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}
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bool compare(const DomTreeNodeBase<NodeT> *Other) const {
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if (getNumChildren() != Other->getNumChildren())
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return true;
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SmallPtrSet<const NodeT *, 4> OtherChildren;
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for (const_iterator I = Other->begin(), E = Other->end(); I != E; ++I) {
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const NodeT *Nd = (*I)->getBlock();
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OtherChildren.insert(Nd);
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}
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for (const_iterator I = begin(), E = end(); I != E; ++I) {
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const NodeT *N = (*I)->getBlock();
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if (OtherChildren.count(N) == 0)
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return true;
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}
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return false;
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}
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void setIDom(DomTreeNodeBase<NodeT> *NewIDom) {
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assert(IDom && "No immediate dominator?");
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if (IDom != NewIDom) {
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typename std::vector<DomTreeNodeBase<NodeT>*>::iterator I =
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std::find(IDom->Children.begin(), IDom->Children.end(), this);
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assert(I != IDom->Children.end() &&
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"Not in immediate dominator children set!");
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// I am no longer your child...
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IDom->Children.erase(I);
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// Switch to new dominator
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IDom = NewIDom;
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IDom->Children.push_back(this);
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}
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}
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/// getDFSNumIn/getDFSNumOut - These are an internal implementation detail, do
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/// not call them.
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unsigned getDFSNumIn() const { return DFSNumIn; }
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unsigned getDFSNumOut() const { return DFSNumOut; }
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private:
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// Return true if this node is dominated by other. Use this only if DFS info
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// is valid.
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bool DominatedBy(const DomTreeNodeBase<NodeT> *other) const {
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return this->DFSNumIn >= other->DFSNumIn &&
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this->DFSNumOut <= other->DFSNumOut;
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}
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};
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template<class NodeT>
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inline raw_ostream &operator<<(raw_ostream &o,
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const DomTreeNodeBase<NodeT> *Node) {
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if (Node->getBlock())
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Node->getBlock()->printAsOperand(o, false);
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else
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o << " <<exit node>>";
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o << " {" << Node->getDFSNumIn() << "," << Node->getDFSNumOut() << "}";
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return o << "\n";
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}
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template<class NodeT>
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inline void PrintDomTree(const DomTreeNodeBase<NodeT> *N, raw_ostream &o,
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unsigned Lev) {
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o.indent(2*Lev) << "[" << Lev << "] " << N;
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for (typename DomTreeNodeBase<NodeT>::const_iterator I = N->begin(),
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E = N->end(); I != E; ++I)
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PrintDomTree<NodeT>(*I, o, Lev+1);
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}
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//===----------------------------------------------------------------------===//
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/// DominatorTree - Calculate the immediate dominator tree for a function.
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///
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template<class FuncT, class N>
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void Calculate(DominatorTreeBase<typename GraphTraits<N>::NodeType>& DT,
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FuncT& F);
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template<class NodeT>
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class DominatorTreeBase : public DominatorBase<NodeT> {
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bool dominatedBySlowTreeWalk(const DomTreeNodeBase<NodeT> *A,
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const DomTreeNodeBase<NodeT> *B) const {
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assert(A != B);
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assert(isReachableFromEntry(B));
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assert(isReachableFromEntry(A));
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const DomTreeNodeBase<NodeT> *IDom;
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2014-04-09 06:08:46 +00:00
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while ((IDom = B->getIDom()) != nullptr && IDom != A && IDom != B)
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2014-01-13 10:52:56 +00:00
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B = IDom; // Walk up the tree
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2014-04-09 06:08:46 +00:00
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return IDom != nullptr;
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2014-01-13 10:52:56 +00:00
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}
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protected:
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typedef DenseMap<NodeT*, DomTreeNodeBase<NodeT>*> DomTreeNodeMapType;
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DomTreeNodeMapType DomTreeNodes;
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DomTreeNodeBase<NodeT> *RootNode;
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2014-01-13 11:58:34 +00:00
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mutable bool DFSInfoValid;
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mutable unsigned int SlowQueries;
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2014-01-13 10:52:56 +00:00
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// Information record used during immediate dominators computation.
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struct InfoRec {
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unsigned DFSNum;
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unsigned Parent;
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unsigned Semi;
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NodeT *Label;
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2014-04-09 06:08:46 +00:00
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InfoRec() : DFSNum(0), Parent(0), Semi(0), Label(nullptr) {}
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2014-01-13 10:52:56 +00:00
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};
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DenseMap<NodeT*, NodeT*> IDoms;
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// Vertex - Map the DFS number to the NodeT*
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std::vector<NodeT*> Vertex;
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// Info - Collection of information used during the computation of idoms.
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DenseMap<NodeT*, InfoRec> Info;
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void reset() {
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for (typename DomTreeNodeMapType::iterator I = this->DomTreeNodes.begin(),
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E = DomTreeNodes.end(); I != E; ++I)
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delete I->second;
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DomTreeNodes.clear();
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IDoms.clear();
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this->Roots.clear();
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Vertex.clear();
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2014-04-09 06:08:46 +00:00
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RootNode = nullptr;
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2014-01-13 10:52:56 +00:00
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}
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// NewBB is split and now it has one successor. Update dominator tree to
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// reflect this change.
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template<class N, class GraphT>
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void Split(DominatorTreeBase<typename GraphT::NodeType>& DT,
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typename GraphT::NodeType* NewBB) {
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assert(std::distance(GraphT::child_begin(NewBB),
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GraphT::child_end(NewBB)) == 1 &&
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"NewBB should have a single successor!");
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typename GraphT::NodeType* NewBBSucc = *GraphT::child_begin(NewBB);
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std::vector<typename GraphT::NodeType*> PredBlocks;
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typedef GraphTraits<Inverse<N> > InvTraits;
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for (typename InvTraits::ChildIteratorType PI =
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InvTraits::child_begin(NewBB),
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PE = InvTraits::child_end(NewBB); PI != PE; ++PI)
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PredBlocks.push_back(*PI);
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assert(!PredBlocks.empty() && "No predblocks?");
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bool NewBBDominatesNewBBSucc = true;
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for (typename InvTraits::ChildIteratorType PI =
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InvTraits::child_begin(NewBBSucc),
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E = InvTraits::child_end(NewBBSucc); PI != E; ++PI) {
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typename InvTraits::NodeType *ND = *PI;
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if (ND != NewBB && !DT.dominates(NewBBSucc, ND) &&
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DT.isReachableFromEntry(ND)) {
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NewBBDominatesNewBBSucc = false;
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break;
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}
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}
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// Find NewBB's immediate dominator and create new dominator tree node for
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// NewBB.
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2014-04-09 06:08:46 +00:00
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NodeT *NewBBIDom = nullptr;
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2014-01-13 10:52:56 +00:00
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unsigned i = 0;
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for (i = 0; i < PredBlocks.size(); ++i)
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if (DT.isReachableFromEntry(PredBlocks[i])) {
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NewBBIDom = PredBlocks[i];
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break;
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}
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// It's possible that none of the predecessors of NewBB are reachable;
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// in that case, NewBB itself is unreachable, so nothing needs to be
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// changed.
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if (!NewBBIDom)
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return;
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for (i = i + 1; i < PredBlocks.size(); ++i) {
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if (DT.isReachableFromEntry(PredBlocks[i]))
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NewBBIDom = DT.findNearestCommonDominator(NewBBIDom, PredBlocks[i]);
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}
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// Create the new dominator tree node... and set the idom of NewBB.
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DomTreeNodeBase<NodeT> *NewBBNode = DT.addNewBlock(NewBB, NewBBIDom);
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// If NewBB strictly dominates other blocks, then it is now the immediate
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// dominator of NewBBSucc. Update the dominator tree as appropriate.
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if (NewBBDominatesNewBBSucc) {
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DomTreeNodeBase<NodeT> *NewBBSuccNode = DT.getNode(NewBBSucc);
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DT.changeImmediateDominator(NewBBSuccNode, NewBBNode);
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}
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}
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public:
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explicit DominatorTreeBase(bool isPostDom)
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: DominatorBase<NodeT>(isPostDom), DFSInfoValid(false), SlowQueries(0) {}
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virtual ~DominatorTreeBase() { reset(); }
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/// compare - Return false if the other dominator tree base matches this
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/// dominator tree base. Otherwise return true.
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2014-01-13 13:07:17 +00:00
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bool compare(const DominatorTreeBase &Other) const {
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2014-01-13 10:52:56 +00:00
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const DomTreeNodeMapType &OtherDomTreeNodes = Other.DomTreeNodes;
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if (DomTreeNodes.size() != OtherDomTreeNodes.size())
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return true;
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for (typename DomTreeNodeMapType::const_iterator
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I = this->DomTreeNodes.begin(),
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E = this->DomTreeNodes.end(); I != E; ++I) {
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NodeT *BB = I->first;
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typename DomTreeNodeMapType::const_iterator OI = OtherDomTreeNodes.find(BB);
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if (OI == OtherDomTreeNodes.end())
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return true;
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DomTreeNodeBase<NodeT>* MyNd = I->second;
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DomTreeNodeBase<NodeT>* OtherNd = OI->second;
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if (MyNd->compare(OtherNd))
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return true;
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}
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return false;
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}
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virtual void releaseMemory() { reset(); }
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/// getNode - return the (Post)DominatorTree node for the specified basic
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/// block. This is the same as using operator[] on this class.
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///
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inline DomTreeNodeBase<NodeT> *getNode(NodeT *BB) const {
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return DomTreeNodes.lookup(BB);
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}
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2014-07-02 06:50:48 +00:00
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inline DomTreeNodeBase<NodeT> *operator[](NodeT *BB) const {
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return getNode(BB);
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}
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2014-01-13 10:52:56 +00:00
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/// getRootNode - This returns the entry node for the CFG of the function. If
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/// this tree represents the post-dominance relations for a function, however,
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/// this root may be a node with the block == NULL. This is the case when
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/// there are multiple exit nodes from a particular function. Consumers of
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/// post-dominance information must be capable of dealing with this
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/// possibility.
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///
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DomTreeNodeBase<NodeT> *getRootNode() { return RootNode; }
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const DomTreeNodeBase<NodeT> *getRootNode() const { return RootNode; }
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/// Get all nodes dominated by R, including R itself.
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void getDescendants(NodeT *R, SmallVectorImpl<NodeT *> &Result) const {
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Result.clear();
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const DomTreeNodeBase<NodeT> *RN = getNode(R);
|
2014-04-09 06:08:46 +00:00
|
|
|
if (!RN)
|
2014-01-13 10:52:56 +00:00
|
|
|
return; // If R is unreachable, it will not be present in the DOM tree.
|
|
|
|
SmallVector<const DomTreeNodeBase<NodeT> *, 8> WL;
|
|
|
|
WL.push_back(RN);
|
|
|
|
|
|
|
|
while (!WL.empty()) {
|
|
|
|
const DomTreeNodeBase<NodeT> *N = WL.pop_back_val();
|
|
|
|
Result.push_back(N->getBlock());
|
|
|
|
WL.append(N->begin(), N->end());
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
/// properlyDominates - Returns true iff A dominates B and A != B.
|
|
|
|
/// Note that this is not a constant time operation!
|
|
|
|
///
|
|
|
|
bool properlyDominates(const DomTreeNodeBase<NodeT> *A,
|
2014-01-13 11:58:34 +00:00
|
|
|
const DomTreeNodeBase<NodeT> *B) const {
|
2014-04-09 06:08:46 +00:00
|
|
|
if (!A || !B)
|
2014-01-13 10:52:56 +00:00
|
|
|
return false;
|
|
|
|
if (A == B)
|
|
|
|
return false;
|
|
|
|
return dominates(A, B);
|
|
|
|
}
|
|
|
|
|
2014-01-13 11:58:34 +00:00
|
|
|
bool properlyDominates(const NodeT *A, const NodeT *B) const;
|
2014-01-13 10:52:56 +00:00
|
|
|
|
|
|
|
/// isReachableFromEntry - Return true if A is dominated by the entry
|
|
|
|
/// block of the function containing it.
|
|
|
|
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
|
|
|
|
/// constant time operation!
|
|
|
|
///
|
|
|
|
inline bool dominates(const DomTreeNodeBase<NodeT> *A,
|
2014-01-13 11:58:34 +00:00
|
|
|
const DomTreeNodeBase<NodeT> *B) const {
|
2014-01-13 10:52:56 +00:00
|
|
|
// A node trivially dominates itself.
|
|
|
|
if (B == A)
|
|
|
|
return true;
|
|
|
|
|
|
|
|
// 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);
|
|
|
|
|
|
|
|
// 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);
|
|
|
|
}
|
|
|
|
|
|
|
|
return dominatedBySlowTreeWalk(A, B);
|
|
|
|
}
|
|
|
|
|
2014-01-13 11:58:34 +00:00
|
|
|
bool dominates(const NodeT *A, const NodeT *B) const;
|
2014-01-13 10:52:56 +00:00
|
|
|
|
|
|
|
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(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))
|
|
|
|
return B;
|
|
|
|
|
|
|
|
// If A dominates B then A is nearest common dominator.
|
|
|
|
if (dominates(A, B))
|
|
|
|
return A;
|
|
|
|
|
|
|
|
DomTreeNodeBase<NodeT> *NodeA = getNode(A);
|
|
|
|
DomTreeNodeBase<NodeT> *NodeB = getNode(B);
|
|
|
|
|
2014-04-28 09:34:03 +00:00
|
|
|
// If we have DFS info, then we can avoid all allocations by just querying
|
|
|
|
// it from each IDom. Note that because we call 'dominates' twice above, we
|
|
|
|
// expect to call through this code at most 16 times in a row without
|
|
|
|
// building valid DFS information. This is important as below is a *very*
|
|
|
|
// slow tree walk.
|
|
|
|
if (DFSInfoValid) {
|
|
|
|
DomTreeNodeBase<NodeT> *IDomA = NodeA->getIDom();
|
|
|
|
while (IDomA) {
|
|
|
|
if (NodeB->DominatedBy(IDomA))
|
|
|
|
return IDomA->getBlock();
|
|
|
|
IDomA = IDomA->getIDom();
|
|
|
|
}
|
|
|
|
return nullptr;
|
|
|
|
}
|
|
|
|
|
2014-01-13 10:52:56 +00:00
|
|
|
// Collect NodeA dominators set.
|
|
|
|
SmallPtrSet<DomTreeNodeBase<NodeT>*, 16> NodeADoms;
|
|
|
|
NodeADoms.insert(NodeA);
|
|
|
|
DomTreeNodeBase<NodeT> *IDomA = NodeA->getIDom();
|
|
|
|
while (IDomA) {
|
|
|
|
NodeADoms.insert(IDomA);
|
|
|
|
IDomA = IDomA->getIDom();
|
|
|
|
}
|
|
|
|
|
|
|
|
// Walk NodeB immediate dominators chain and find common dominator node.
|
|
|
|
DomTreeNodeBase<NodeT> *IDomB = NodeB->getIDom();
|
|
|
|
while (IDomB) {
|
|
|
|
if (NodeADoms.count(IDomB) != 0)
|
|
|
|
return IDomB->getBlock();
|
|
|
|
|
|
|
|
IDomB = IDomB->getIDom();
|
|
|
|
}
|
|
|
|
|
2014-04-09 06:08:46 +00:00
|
|
|
return nullptr;
|
2014-01-13 10:52:56 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
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
|
|
|
|
/// the children list of the immediate dominator.
|
|
|
|
DomTreeNodeBase<NodeT> *addNewBlock(NodeT *BB, NodeT *DomBB) {
|
2014-04-14 00:51:57 +00:00
|
|
|
assert(getNode(BB) == nullptr && "Block already in dominator tree!");
|
2014-01-13 10:52:56 +00:00
|
|
|
DomTreeNodeBase<NodeT> *IDomNode = getNode(DomBB);
|
|
|
|
assert(IDomNode && "Not immediate dominator specified for block!");
|
|
|
|
DFSInfoValid = false;
|
|
|
|
return DomTreeNodes[BB] =
|
|
|
|
IDomNode->addChild(new DomTreeNodeBase<NodeT>(BB, IDomNode));
|
|
|
|
}
|
|
|
|
|
|
|
|
/// changeImmediateDominator - This method is used to update the dominator
|
|
|
|
/// tree information when a node's immediate dominator changes.
|
|
|
|
///
|
|
|
|
void changeImmediateDominator(DomTreeNodeBase<NodeT> *N,
|
|
|
|
DomTreeNodeBase<NodeT> *NewIDom) {
|
|
|
|
assert(N && NewIDom && "Cannot change null node pointers!");
|
|
|
|
DFSInfoValid = false;
|
|
|
|
N->setIDom(NewIDom);
|
|
|
|
}
|
|
|
|
|
|
|
|
void changeImmediateDominator(NodeT *BB, NodeT *NewBB) {
|
|
|
|
changeImmediateDominator(getNode(BB), getNode(NewBB));
|
|
|
|
}
|
|
|
|
|
|
|
|
/// 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.");
|
|
|
|
|
|
|
|
// Remove node from immediate dominator's children list.
|
|
|
|
DomTreeNodeBase<NodeT> *IDom = Node->getIDom();
|
|
|
|
if (IDom) {
|
|
|
|
typename std::vector<DomTreeNodeBase<NodeT>*>::iterator I =
|
|
|
|
std::find(IDom->Children.begin(), IDom->Children.end(), Node);
|
|
|
|
assert(I != IDom->Children.end() &&
|
|
|
|
"Not in immediate dominator children set!");
|
|
|
|
// I am no longer your child...
|
|
|
|
IDom->Children.erase(I);
|
|
|
|
}
|
|
|
|
|
|
|
|
DomTreeNodes.erase(BB);
|
|
|
|
delete Node;
|
|
|
|
}
|
|
|
|
|
|
|
|
/// removeNode - Removes a node from the dominator tree. Block must not
|
|
|
|
/// dominate any other blocks. Invalidates any node pointing to removed
|
|
|
|
/// block.
|
|
|
|
void removeNode(NodeT *BB) {
|
|
|
|
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) {
|
|
|
|
if (this->IsPostDominators)
|
|
|
|
this->Split<Inverse<NodeT*>, GraphTraits<Inverse<NodeT*> > >(*this, NewBB);
|
|
|
|
else
|
|
|
|
this->Split<NodeT*, GraphTraits<NodeT*> >(*this, NewBB);
|
|
|
|
}
|
|
|
|
|
|
|
|
/// print - Convert to human readable form
|
|
|
|
///
|
|
|
|
void print(raw_ostream &o) const {
|
|
|
|
o << "=============================--------------------------------\n";
|
|
|
|
if (this->isPostDominator())
|
|
|
|
o << "Inorder PostDominator Tree: ";
|
|
|
|
else
|
|
|
|
o << "Inorder Dominator Tree: ";
|
|
|
|
if (!this->DFSInfoValid)
|
|
|
|
o << "DFSNumbers invalid: " << SlowQueries << " slow queries.";
|
|
|
|
o << "\n";
|
|
|
|
|
|
|
|
// The postdom tree can have a null root if there are no returns.
|
|
|
|
if (getRootNode())
|
|
|
|
PrintDomTree<NodeT>(getRootNode(), o, 1);
|
|
|
|
}
|
|
|
|
|
|
|
|
protected:
|
|
|
|
template<class GraphT>
|
|
|
|
friend typename GraphT::NodeType* Eval(
|
|
|
|
DominatorTreeBase<typename GraphT::NodeType>& DT,
|
|
|
|
typename GraphT::NodeType* V,
|
|
|
|
unsigned LastLinked);
|
|
|
|
|
|
|
|
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.
|
2014-01-13 11:58:34 +00:00
|
|
|
void updateDFSNumbers() const {
|
2014-01-13 10:52:56 +00:00
|
|
|
unsigned DFSNum = 0;
|
|
|
|
|
2014-01-13 11:58:34 +00:00
|
|
|
SmallVector<std::pair<const DomTreeNodeBase<NodeT>*,
|
|
|
|
typename DomTreeNodeBase<NodeT>::const_iterator>, 32> WorkStack;
|
2014-01-13 10:52:56 +00:00
|
|
|
|
2014-01-13 11:58:34 +00:00
|
|
|
const DomTreeNodeBase<NodeT> *ThisRoot = getRootNode();
|
2014-01-13 10:52:56 +00:00
|
|
|
|
|
|
|
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()) {
|
2014-01-13 11:58:34 +00:00
|
|
|
const DomTreeNodeBase<NodeT> *Node = WorkStack.back().first;
|
|
|
|
typename DomTreeNodeBase<NodeT>::const_iterator ChildIt =
|
2014-01-13 10:52:56 +00:00
|
|
|
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.
|
2014-01-13 11:58:34 +00:00
|
|
|
const DomTreeNodeBase<NodeT> *Child = *ChildIt;
|
2014-01-13 10:52:56 +00:00
|
|
|
++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> *Node = getNode(BB))
|
|
|
|
return Node;
|
|
|
|
|
|
|
|
// Haven't calculated this node yet? Get or calculate the node for the
|
|
|
|
// immediate dominator.
|
|
|
|
NodeT *IDom = getIDom(BB);
|
|
|
|
|
2014-04-14 00:51:57 +00:00
|
|
|
assert(IDom || this->DomTreeNodes[nullptr]);
|
2014-01-13 10:52:56 +00:00
|
|
|
DomTreeNodeBase<NodeT> *IDomNode = getNodeForBlock(IDom);
|
|
|
|
|
|
|
|
// Add a new tree node for this NodeT, 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 {
|
|
|
|
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();
|
2014-04-09 06:08:46 +00:00
|
|
|
this->Vertex.push_back(nullptr);
|
2014-01-13 10:52:56 +00:00
|
|
|
|
|
|
|
if (!this->IsPostDominators) {
|
|
|
|
// Initialize root
|
|
|
|
NodeT *entry = TraitsTy::getEntryNode(&F);
|
|
|
|
this->Roots.push_back(entry);
|
2014-04-09 06:08:46 +00:00
|
|
|
this->IDoms[entry] = nullptr;
|
|
|
|
this->DomTreeNodes[entry] = nullptr;
|
2014-01-13 10:52:56 +00:00
|
|
|
|
|
|
|
Calculate<FT, NodeT*>(*this, F);
|
|
|
|
} else {
|
|
|
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// Initialize the roots list
|
|
|
|
for (typename TraitsTy::nodes_iterator I = TraitsTy::nodes_begin(&F),
|
|
|
|
E = TraitsTy::nodes_end(&F); I != E; ++I) {
|
|
|
|
if (TraitsTy::child_begin(I) == TraitsTy::child_end(I))
|
|
|
|
addRoot(I);
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|
|
|
|
|
|
|
// Prepopulate maps so that we don't get iterator invalidation issues later.
|
2014-04-09 06:08:46 +00:00
|
|
|
this->IDoms[I] = nullptr;
|
|
|
|
this->DomTreeNodes[I] = nullptr;
|
2014-01-13 10:52:56 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
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>
|
2014-01-13 11:58:34 +00:00
|
|
|
bool DominatorTreeBase<NodeT>::dominates(const NodeT *A, const NodeT *B) const {
|
2014-01-13 10:52:56 +00:00
|
|
|
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
|
2014-01-13 11:58:34 +00:00
|
|
|
DominatorTreeBase<NodeT>::properlyDominates(const NodeT *A, const NodeT *B) const {
|
2014-01-13 10:52:56 +00:00
|
|
|
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)));
|
|
|
|
}
|
|
|
|
|
|
|
|
}
|
|
|
|
|
|
|
|
#endif
|