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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47680 91177308-0d34-0410-b5e6-96231b3b80d8
960 lines
32 KiB
C++
960 lines
32 KiB
C++
//===- llvm/Analysis/Dominators.h - Dominator Info Calculation --*- 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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//
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// This file defines the following classes:
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// 1. DominatorTree: Represent dominators as an explicit tree structure.
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// 2. DominanceFrontier: Calculate and hold the dominance frontier for a
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// function.
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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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// DominatorTree mapping.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_ANALYSIS_DOMINATORS_H
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#define LLVM_ANALYSIS_DOMINATORS_H
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#include "llvm/Pass.h"
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#include "llvm/BasicBlock.h"
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#include "llvm/Function.h"
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#include "llvm/Instruction.h"
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#include "llvm/Instructions.h"
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#include "llvm/ADT/DenseMap.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/Assembly/Writer.h"
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#include "llvm/Support/CFG.h"
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#include "llvm/Support/Compiler.h"
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#include <algorithm>
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#include <set>
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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 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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// DomTreeNode - Dominator Tree Node
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template<class NodeT> class DominatorTreeBase;
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struct PostDominatorTree;
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class MachineBasicBlock;
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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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int DFSNumIn, DFSNumOut;
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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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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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EXTERN_TEMPLATE_INSTANTIATION(class DomTreeNodeBase<BasicBlock>);
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EXTERN_TEMPLATE_INSTANTIATION(class DomTreeNodeBase<MachineBasicBlock>);
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template<class NodeT>
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static std::ostream &operator<<(std::ostream &o,
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const DomTreeNodeBase<NodeT> *Node) {
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if (Node->getBlock())
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WriteAsOperand(o, Node->getBlock(), 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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static void PrintDomTree(const DomTreeNodeBase<NodeT> *N, std::ostream &o,
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unsigned Lev) {
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o << std::string(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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typedef DomTreeNodeBase<BasicBlock> DomTreeNode;
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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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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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bool DFSInfoValid;
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unsigned int SlowQueries;
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// Information record used during immediate dominators computation.
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struct InfoRec {
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unsigned Semi;
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unsigned Size;
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NodeT *Label, *Parent, *Child, *Ancestor;
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std::vector<NodeT*> Bucket;
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InfoRec() : Semi(0), Size(0), Label(0), Parent(0), Child(0), Ancestor(0) {}
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};
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DenseMap<NodeT*, NodeT*> IDoms;
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// Vertex - Map the DFS number to the BasicBlock*
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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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RootNode = 0;
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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), 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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for (typename GraphTraits<Inverse<N> >::ChildIteratorType PI =
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GraphTraits<Inverse<N> >::child_begin(NewBB),
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PE = GraphTraits<Inverse<N> >::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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// The newly inserted basic block will dominate existing basic blocks iff the
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// PredBlocks dominate all of the non-pred blocks. If all predblocks dominate
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// the non-pred blocks, then they all must be the same block!
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//
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bool NewBBDominatesNewBBSucc = true;
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{
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typename GraphT::NodeType* OnePred = PredBlocks[0];
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unsigned i = 1, e = PredBlocks.size();
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for (i = 1; !DT.isReachableFromEntry(OnePred); ++i) {
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assert(i != e && "Didn't find reachable pred?");
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OnePred = PredBlocks[i];
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}
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for (; i != e; ++i)
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if (PredBlocks[i] != OnePred && DT.isReachableFromEntry(OnePred)) {
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NewBBDominatesNewBBSucc = false;
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break;
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}
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if (NewBBDominatesNewBBSucc)
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for (typename GraphTraits<Inverse<N> >::ChildIteratorType PI =
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GraphTraits<Inverse<N> >::child_begin(NewBBSucc),
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E = GraphTraits<Inverse<N> >::child_end(NewBBSucc); PI != E; ++PI)
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if (*PI != NewBB && !DT.dominates(NewBBSucc, *PI)) {
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NewBBDominatesNewBBSucc = false;
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break;
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}
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}
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// The other scenario where the new block can dominate its successors are when
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// all predecessors of NewBBSucc that are not NewBB are dominated by NewBBSucc
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// already.
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if (!NewBBDominatesNewBBSucc) {
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NewBBDominatesNewBBSucc = true;
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for (typename GraphTraits<Inverse<N> >::ChildIteratorType PI =
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GraphTraits<Inverse<N> >::child_begin(NewBBSucc),
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E = GraphTraits<Inverse<N> >::child_end(NewBBSucc); PI != E; ++PI)
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if (*PI != NewBB && !DT.dominates(NewBBSucc, *PI)) {
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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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NodeT *NewBBIDom = 0;
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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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assert(i != PredBlocks.size() && "No reachable preds?");
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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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assert(NewBBIDom && "No immediate dominator found??");
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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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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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// FIXME: Should remove this
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virtual bool runOnFunction(Function &F) { return false; }
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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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typename DomTreeNodeMapType::const_iterator I = DomTreeNodes.find(BB);
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return I != DomTreeNodes.end() ? I->second : 0;
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}
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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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/// properlyDominates - Returns true iff this dominates N and this != N.
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/// Note that this is not a constant time operation!
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///
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bool properlyDominates(const DomTreeNodeBase<NodeT> *A,
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DomTreeNodeBase<NodeT> *B) const {
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if (A == 0 || B == 0) return false;
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return dominatedBySlowTreeWalk(A, B);
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}
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inline bool properlyDominates(NodeT *A, NodeT *B) {
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return properlyDominates(getNode(A), getNode(B));
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}
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bool dominatedBySlowTreeWalk(const DomTreeNodeBase<NodeT> *A,
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const DomTreeNodeBase<NodeT> *B) const {
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const DomTreeNodeBase<NodeT> *IDom;
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if (A == 0 || B == 0) return false;
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while ((IDom = B->getIDom()) != 0 && IDom != A && IDom != B)
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B = IDom; // Walk up the tree
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return IDom != 0;
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}
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/// isReachableFromEntry - Return true if A is dominated by the entry
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/// block of the function containing it.
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bool isReachableFromEntry(NodeT* A) {
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assert (!this->isPostDominator()
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&& "This is not implemented for post dominators");
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return dominates(&A->getParent()->front(), A);
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}
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/// dominates - Returns true iff A dominates B. Note that this is not a
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/// constant time operation!
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///
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inline bool dominates(const DomTreeNodeBase<NodeT> *A,
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DomTreeNodeBase<NodeT> *B) {
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if (B == A)
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return true; // A node trivially dominates itself.
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if (A == 0 || B == 0)
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return false;
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if (DFSInfoValid)
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return B->DominatedBy(A);
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// If we end up with too many slow queries, just update the
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// DFS numbers on the theory that we are going to keep querying.
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SlowQueries++;
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if (SlowQueries > 32) {
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updateDFSNumbers();
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return B->DominatedBy(A);
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}
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return dominatedBySlowTreeWalk(A, B);
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}
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inline bool dominates(NodeT *A, NodeT *B) {
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if (A == B)
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return true;
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return dominates(getNode(A), getNode(B));
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}
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NodeT *getRoot() const {
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assert(this->Roots.size() == 1 && "Should always have entry node!");
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return this->Roots[0];
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}
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/// findNearestCommonDominator - Find nearest common dominator basic block
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/// for basic block A and B. If there is no such block then return NULL.
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NodeT *findNearestCommonDominator(NodeT *A, NodeT *B) {
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assert (!this->isPostDominator()
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&& "This is not implemented for post dominators");
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assert (A->getParent() == B->getParent()
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&& "Two blocks are not in same function");
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// If either A or B is a entry block then it is nearest common dominator.
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NodeT &Entry = A->getParent()->front();
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if (A == &Entry || B == &Entry)
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return &Entry;
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// If B dominates A then B is nearest common dominator.
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if (dominates(B, A))
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return B;
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// If A dominates B then A is nearest common dominator.
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if (dominates(A, B))
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return A;
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DomTreeNodeBase<NodeT> *NodeA = getNode(A);
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DomTreeNodeBase<NodeT> *NodeB = getNode(B);
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// Collect NodeA dominators set.
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SmallPtrSet<DomTreeNodeBase<NodeT>*, 16> NodeADoms;
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NodeADoms.insert(NodeA);
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DomTreeNodeBase<NodeT> *IDomA = NodeA->getIDom();
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while (IDomA) {
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NodeADoms.insert(IDomA);
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IDomA = IDomA->getIDom();
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}
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// Walk NodeB immediate dominators chain and find common dominator node.
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DomTreeNodeBase<NodeT> *IDomB = NodeB->getIDom();
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while(IDomB) {
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if (NodeADoms.count(IDomB) != 0)
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return IDomB->getBlock();
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IDomB = IDomB->getIDom();
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}
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return NULL;
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}
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//===--------------------------------------------------------------------===//
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// API to update (Post)DominatorTree information based on modifications to
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// the CFG...
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/// addNewBlock - Add a new node to the dominator tree information. This
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/// creates a new node as a child of DomBB dominator node,linking it into
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/// the children list of the immediate dominator.
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DomTreeNodeBase<NodeT> *addNewBlock(NodeT *BB, NodeT *DomBB) {
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assert(getNode(BB) == 0 && "Block already in dominator tree!");
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DomTreeNodeBase<NodeT> *IDomNode = getNode(DomBB);
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assert(IDomNode && "Not immediate dominator specified for block!");
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DFSInfoValid = false;
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return DomTreeNodes[BB] =
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IDomNode->addChild(new DomTreeNodeBase<NodeT>(BB, IDomNode));
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}
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/// changeImmediateDominator - This method is used to update the dominator
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/// tree information when a node's immediate dominator changes.
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///
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void changeImmediateDominator(DomTreeNodeBase<NodeT> *N,
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DomTreeNodeBase<NodeT> *NewIDom) {
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assert(N && NewIDom && "Cannot change null node pointers!");
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DFSInfoValid = false;
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N->setIDom(NewIDom);
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}
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void changeImmediateDominator(NodeT *BB, NodeT *NewBB) {
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changeImmediateDominator(getNode(BB), getNode(NewBB));
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}
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/// eraseNode - Removes a node from the dominator tree. Block must not
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/// domiante any other blocks. Removes node from its immediate dominator's
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/// children list. Deletes dominator node associated with basic block BB.
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void eraseNode(NodeT *BB) {
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DomTreeNodeBase<NodeT> *Node = getNode(BB);
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assert (Node && "Removing node that isn't in dominator tree.");
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assert (Node->getChildren().empty() && "Node is not a leaf node.");
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// 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
|
|
///
|
|
virtual void print(std::ostream &o, const Module* ) 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";
|
|
|
|
PrintDomTree<NodeT>(getRootNode(), o, 1);
|
|
}
|
|
|
|
void print(std::ostream *OS, const Module* M = 0) const {
|
|
if (OS) print(*OS, M);
|
|
}
|
|
|
|
virtual void dump() {
|
|
print(llvm::cerr);
|
|
}
|
|
|
|
protected:
|
|
template<class GraphT>
|
|
friend void Compress(DominatorTreeBase<typename GraphT::NodeType>& DT,
|
|
typename GraphT::NodeType* VIn);
|
|
|
|
template<class GraphT>
|
|
friend typename GraphT::NodeType* Eval(
|
|
DominatorTreeBase<typename GraphT::NodeType>& DT,
|
|
typename GraphT::NodeType* V);
|
|
|
|
template<class GraphT>
|
|
friend void Link(DominatorTreeBase<typename GraphT::NodeType>& DT,
|
|
typename GraphT::NodeType* V,
|
|
typename GraphT::NodeType* W,
|
|
typename DominatorTreeBase<typename GraphT::NodeType>::InfoRec &WInfo);
|
|
|
|
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.
|
|
void updateDFSNumbers() {
|
|
unsigned DFSNum = 0;
|
|
|
|
SmallVector<std::pair<DomTreeNodeBase<NodeT>*,
|
|
typename DomTreeNodeBase<NodeT>::iterator>, 32> WorkStack;
|
|
|
|
for (unsigned i = 0, e = this->Roots.size(); i != e; ++i) {
|
|
DomTreeNodeBase<NodeT> *ThisRoot = getNode(this->Roots[i]);
|
|
WorkStack.push_back(std::make_pair(ThisRoot, ThisRoot->begin()));
|
|
ThisRoot->DFSNumIn = DFSNum++;
|
|
|
|
while (!WorkStack.empty()) {
|
|
DomTreeNodeBase<NodeT> *Node = WorkStack.back().first;
|
|
typename DomTreeNodeBase<NodeT>::iterator ChildIt =
|
|
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.
|
|
DomTreeNodeBase<NodeT> *Child = *ChildIt;
|
|
++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> *BBNode = this->DomTreeNodes[BB])
|
|
return BBNode;
|
|
|
|
// Haven't calculated this node yet? Get or calculate the node for the
|
|
// immediate dominator.
|
|
NodeT *IDom = getIDom(BB);
|
|
DomTreeNodeBase<NodeT> *IDomNode = getNodeForBlock(IDom);
|
|
|
|
// Add a new tree node for this BasicBlock, 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 {
|
|
typename DenseMap<NodeT*, NodeT*>::const_iterator I = IDoms.find(BB);
|
|
return I != IDoms.end() ? I->second : 0;
|
|
}
|
|
|
|
inline void addRoot(NodeT* BB) {
|
|
// Unreachable block is not a root node.
|
|
if (!isa<UnreachableInst>(&BB->back()))
|
|
this->Roots.push_back(BB);
|
|
}
|
|
|
|
public:
|
|
/// recalculate - compute a dominator tree for the given function
|
|
template<class FT>
|
|
void recalculate(FT& F) {
|
|
if (!this->IsPostDominators) {
|
|
reset();
|
|
|
|
// Initialize roots
|
|
this->Roots.push_back(&F.front());
|
|
this->IDoms[&F.front()] = 0;
|
|
this->DomTreeNodes[&F.front()] = 0;
|
|
this->Vertex.push_back(0);
|
|
|
|
Calculate<FT, NodeT*>(*this, F);
|
|
|
|
updateDFSNumbers();
|
|
} else {
|
|
reset(); // Reset from the last time we were run...
|
|
|
|
// Initialize the roots list
|
|
for (typename FT::iterator I = F.begin(), E = F.end(); I != E; ++I) {
|
|
if (std::distance(GraphTraits<FT*>::child_begin(I),
|
|
GraphTraits<FT*>::child_end(I)) == 0)
|
|
addRoot(I);
|
|
|
|
// Prepopulate maps so that we don't get iterator invalidation issues later.
|
|
this->IDoms[I] = 0;
|
|
this->DomTreeNodes[I] = 0;
|
|
}
|
|
|
|
this->Vertex.push_back(0);
|
|
|
|
Calculate<FT, Inverse<NodeT*> >(*this, F);
|
|
}
|
|
}
|
|
};
|
|
|
|
EXTERN_TEMPLATE_INSTANTIATION(class DominatorTreeBase<BasicBlock>);
|
|
|
|
//===-------------------------------------
|
|
/// DominatorTree Class - Concrete subclass of DominatorTreeBase that is used to
|
|
/// compute a normal dominator tree.
|
|
///
|
|
class DominatorTree : public FunctionPass {
|
|
public:
|
|
static char ID; // Pass ID, replacement for typeid
|
|
DominatorTreeBase<BasicBlock>* DT;
|
|
|
|
DominatorTree() : FunctionPass(intptr_t(&ID)) {
|
|
DT = new DominatorTreeBase<BasicBlock>(false);
|
|
}
|
|
|
|
~DominatorTree() {
|
|
DT->releaseMemory();
|
|
delete DT;
|
|
}
|
|
|
|
DominatorTreeBase<BasicBlock>& getBase() { return *DT; }
|
|
|
|
/// 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).
|
|
///
|
|
inline const std::vector<BasicBlock*> &getRoots() const {
|
|
return DT->getRoots();
|
|
}
|
|
|
|
inline BasicBlock *getRoot() const {
|
|
return DT->getRoot();
|
|
}
|
|
|
|
inline DomTreeNode *getRootNode() const {
|
|
return DT->getRootNode();
|
|
}
|
|
|
|
virtual bool runOnFunction(Function &F);
|
|
|
|
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
|
|
AU.setPreservesAll();
|
|
}
|
|
|
|
inline bool dominates(DomTreeNode* A, DomTreeNode* B) const {
|
|
return DT->dominates(A, B);
|
|
}
|
|
|
|
inline bool dominates(BasicBlock* A, BasicBlock* B) const {
|
|
return DT->dominates(A, 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) const {
|
|
BasicBlock *BBA = A->getParent(), *BBB = B->getParent();
|
|
if (BBA != BBB) return DT->dominates(BBA, BBB);
|
|
|
|
// It is not possible to determine dominance between two PHI nodes
|
|
// based on their ordering.
|
|
if (isa<PHINode>(A) && isa<PHINode>(B))
|
|
return false;
|
|
|
|
// Loop through the basic block until we find A or B.
|
|
BasicBlock::iterator I = BBA->begin();
|
|
for (; &*I != A && &*I != B; ++I) /*empty*/;
|
|
|
|
//if(!DT.IsPostDominators) {
|
|
// A dominates B if it is found first in the basic block.
|
|
return &*I == A;
|
|
//} else {
|
|
// // A post-dominates B if B is found first in the basic block.
|
|
// return &*I == B;
|
|
//}
|
|
}
|
|
|
|
inline bool properlyDominates(const DomTreeNode* A, DomTreeNode* B) const {
|
|
return DT->properlyDominates(A, B);
|
|
}
|
|
|
|
inline bool properlyDominates(BasicBlock* A, BasicBlock* B) const {
|
|
return DT->properlyDominates(A, B);
|
|
}
|
|
|
|
/// findNearestCommonDominator - Find nearest common dominator basic block
|
|
/// for basic block A and B. If there is no such block then return NULL.
|
|
inline BasicBlock *findNearestCommonDominator(BasicBlock *A, BasicBlock *B) {
|
|
return DT->findNearestCommonDominator(A, B);
|
|
}
|
|
|
|
inline DomTreeNode *operator[](BasicBlock *BB) const {
|
|
return DT->getNode(BB);
|
|
}
|
|
|
|
/// getNode - return the (Post)DominatorTree node for the specified basic
|
|
/// block. This is the same as using operator[] on this class.
|
|
///
|
|
inline DomTreeNode *getNode(BasicBlock *BB) const {
|
|
return DT->getNode(BB);
|
|
}
|
|
|
|
/// 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.
|
|
inline DomTreeNode *addNewBlock(BasicBlock *BB, BasicBlock *DomBB) {
|
|
return DT->addNewBlock(BB, DomBB);
|
|
}
|
|
|
|
/// changeImmediateDominator - This method is used to update the dominator
|
|
/// tree information when a node's immediate dominator changes.
|
|
///
|
|
inline void changeImmediateDominator(BasicBlock *N, BasicBlock* NewIDom) {
|
|
DT->changeImmediateDominator(N, NewIDom);
|
|
}
|
|
|
|
inline void changeImmediateDominator(DomTreeNode *N, DomTreeNode* NewIDom) {
|
|
DT->changeImmediateDominator(N, NewIDom);
|
|
}
|
|
|
|
/// 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.
|
|
inline void eraseNode(BasicBlock *BB) {
|
|
DT->eraseNode(BB);
|
|
}
|
|
|
|
/// splitBlock - BB is split and now it has one successor. Update dominator
|
|
/// tree to reflect this change.
|
|
inline void splitBlock(BasicBlock* NewBB) {
|
|
DT->splitBlock(NewBB);
|
|
}
|
|
|
|
|
|
virtual void releaseMemory() {
|
|
DT->releaseMemory();
|
|
}
|
|
|
|
virtual void print(std::ostream &OS, const Module* M= 0) const {
|
|
DT->print(OS, M);
|
|
}
|
|
};
|
|
|
|
//===-------------------------------------
|
|
/// DominatorTree GraphTraits specialization so the DominatorTree can be
|
|
/// iterable by generic graph iterators.
|
|
///
|
|
template <> struct GraphTraits<DomTreeNode *> {
|
|
typedef DomTreeNode NodeType;
|
|
typedef NodeType::iterator ChildIteratorType;
|
|
|
|
static NodeType *getEntryNode(NodeType *N) {
|
|
return N;
|
|
}
|
|
static inline ChildIteratorType child_begin(NodeType* N) {
|
|
return N->begin();
|
|
}
|
|
static inline ChildIteratorType child_end(NodeType* N) {
|
|
return N->end();
|
|
}
|
|
};
|
|
|
|
template <> struct GraphTraits<DominatorTree*>
|
|
: public GraphTraits<DomTreeNode *> {
|
|
static NodeType *getEntryNode(DominatorTree *DT) {
|
|
return DT->getRootNode();
|
|
}
|
|
};
|
|
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
/// DominanceFrontierBase - Common base class for computing forward and inverse
|
|
/// dominance frontiers for a function.
|
|
///
|
|
class DominanceFrontierBase : public FunctionPass {
|
|
public:
|
|
typedef std::set<BasicBlock*> DomSetType; // Dom set for a bb
|
|
typedef std::map<BasicBlock*, DomSetType> DomSetMapType; // Dom set map
|
|
protected:
|
|
DomSetMapType Frontiers;
|
|
std::vector<BasicBlock*> Roots;
|
|
const bool IsPostDominators;
|
|
|
|
public:
|
|
DominanceFrontierBase(intptr_t ID, bool isPostDom)
|
|
: FunctionPass(ID), IsPostDominators(isPostDom) {}
|
|
|
|
/// 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).
|
|
///
|
|
inline const std::vector<BasicBlock*> &getRoots() const { return Roots; }
|
|
|
|
/// isPostDominator - Returns true if analysis based of postdoms
|
|
///
|
|
bool isPostDominator() const { return IsPostDominators; }
|
|
|
|
virtual void releaseMemory() { Frontiers.clear(); }
|
|
|
|
// Accessor interface:
|
|
typedef DomSetMapType::iterator iterator;
|
|
typedef DomSetMapType::const_iterator const_iterator;
|
|
iterator begin() { return Frontiers.begin(); }
|
|
const_iterator begin() const { return Frontiers.begin(); }
|
|
iterator end() { return Frontiers.end(); }
|
|
const_iterator end() const { return Frontiers.end(); }
|
|
iterator find(BasicBlock *B) { return Frontiers.find(B); }
|
|
const_iterator find(BasicBlock *B) const { return Frontiers.find(B); }
|
|
|
|
void addBasicBlock(BasicBlock *BB, const DomSetType &frontier) {
|
|
assert(find(BB) == end() && "Block already in DominanceFrontier!");
|
|
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);
|
|
}
|
|
|
|
void removeFromFrontier(iterator I, BasicBlock *Node) {
|
|
assert(I != end() && "BB is not in DominanceFrontier!");
|
|
assert(I->second.count(Node) && "Node is not in DominanceFrontier of BB");
|
|
I->second.erase(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();
|
|
};
|
|
|
|
|
|
//===-------------------------------------
|
|
/// DominanceFrontier Class - Concrete subclass of DominanceFrontierBase that is
|
|
/// used to compute a forward dominator frontiers.
|
|
///
|
|
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!");
|
|
return Roots[0];
|
|
}
|
|
|
|
virtual bool runOnFunction(Function &) {
|
|
Frontiers.clear();
|
|
DominatorTree &DT = getAnalysis<DominatorTree>();
|
|
Roots = DT.getRoots();
|
|
assert(Roots.size() == 1 && "Only one entry block for forward domfronts!");
|
|
calculate(DT, DT[Roots[0]]);
|
|
return false;
|
|
}
|
|
|
|
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
|
|
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 DomTreeNode *Node);
|
|
};
|
|
|
|
|
|
} // End llvm namespace
|
|
|
|
#endif
|