IntervalIterator.h revision 5c3734e349a93e658454f2d4c567e5e0549461f4
1//===- IntervalIterator.h - Interval Iterator Declaration -------*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file was developed by the LLVM research group and is distributed under 6// the University of Illinois Open Source License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file defines an iterator that enumerates the intervals in a control flow 11// graph of some sort. This iterator is parametric, allowing iterator over the 12// following types of graphs: 13// 14// 1. A Function* object, composed of BasicBlock nodes. 15// 2. An IntervalPartition& object, composed of Interval nodes. 16// 17// This iterator is defined to walk the control flow graph, returning intervals 18// in depth first order. These intervals are completely filled in except for 19// the predecessor fields (the successor information is filled in however). 20// 21// By default, the intervals created by this iterator are deleted after they 22// are no longer any use to the iterator. This behavior can be changed by 23// passing a false value into the intervals_begin() function. This causes the 24// IOwnMem member to be set, and the intervals to not be deleted. 25// 26// It is only safe to use this if all of the intervals are deleted by the caller 27// and all of the intervals are processed. However, the user of the iterator is 28// not allowed to modify or delete the intervals until after the iterator has 29// been used completely. The IntervalPartition class uses this functionality. 30// 31//===----------------------------------------------------------------------===// 32 33#ifndef LLVM_INTERVAL_ITERATOR_H 34#define LLVM_INTERVAL_ITERATOR_H 35 36#include "llvm/Analysis/IntervalPartition.h" 37#include "llvm/Function.h" 38#include "llvm/Support/CFG.h" 39#include <stack> 40#include <set> 41#include <algorithm> 42 43namespace llvm { 44 45// getNodeHeader - Given a source graph node and the source graph, return the 46// BasicBlock that is the header node. This is the opposite of 47// getSourceGraphNode. 48// 49inline BasicBlock *getNodeHeader(BasicBlock *BB) { return BB; } 50inline BasicBlock *getNodeHeader(Interval *I) { return I->getHeaderNode(); } 51 52// getSourceGraphNode - Given a BasicBlock and the source graph, return the 53// source graph node that corresponds to the BasicBlock. This is the opposite 54// of getNodeHeader. 55// 56inline BasicBlock *getSourceGraphNode(Function *, BasicBlock *BB) { 57 return BB; 58} 59inline Interval *getSourceGraphNode(IntervalPartition *IP, BasicBlock *BB) { 60 return IP->getBlockInterval(BB); 61} 62 63// addNodeToInterval - This method exists to assist the generic ProcessNode 64// with the task of adding a node to the new interval, depending on the 65// type of the source node. In the case of a CFG source graph (BasicBlock 66// case), the BasicBlock itself is added to the interval. 67// 68inline void addNodeToInterval(Interval *Int, BasicBlock *BB) { 69 Int->Nodes.push_back(BB); 70} 71 72// addNodeToInterval - This method exists to assist the generic ProcessNode 73// with the task of adding a node to the new interval, depending on the 74// type of the source node. In the case of a CFG source graph (BasicBlock 75// case), the BasicBlock itself is added to the interval. In the case of 76// an IntervalPartition source graph (Interval case), all of the member 77// BasicBlocks are added to the interval. 78// 79inline void addNodeToInterval(Interval *Int, Interval *I) { 80 // Add all of the nodes in I as new nodes in Int. 81 copy(I->Nodes.begin(), I->Nodes.end(), back_inserter(Int->Nodes)); 82} 83 84 85 86 87 88template<class NodeTy, class OrigContainer_t, class GT = GraphTraits<NodeTy*>, 89 class IGT = GraphTraits<Inverse<NodeTy*> > > 90class IntervalIterator { 91 std::stack<std::pair<Interval*, typename Interval::succ_iterator> > IntStack; 92 std::set<BasicBlock*> Visited; 93 OrigContainer_t *OrigContainer; 94 bool IOwnMem; // If True, delete intervals when done with them 95 // See file header for conditions of use 96public: 97 typedef BasicBlock* _BB; 98 99 typedef IntervalIterator<NodeTy, OrigContainer_t> _Self; 100 typedef std::forward_iterator_tag iterator_category; 101 102 IntervalIterator() {} // End iterator, empty stack 103 IntervalIterator(Function *M, bool OwnMemory) : IOwnMem(OwnMemory) { 104 OrigContainer = M; 105 if (!ProcessInterval(&M->front())) { 106 assert(0 && "ProcessInterval should never fail for first interval!"); 107 } 108 } 109 110 IntervalIterator(IntervalPartition &IP, bool OwnMemory) : IOwnMem(OwnMemory) { 111 OrigContainer = &IP; 112 if (!ProcessInterval(IP.getRootInterval())) { 113 assert(0 && "ProcessInterval should never fail for first interval!"); 114 } 115 } 116 117 inline ~IntervalIterator() { 118 if (IOwnMem) 119 while (!IntStack.empty()) { 120 delete operator*(); 121 IntStack.pop(); 122 } 123 } 124 125 inline bool operator==(const _Self& x) const { return IntStack == x.IntStack;} 126 inline bool operator!=(const _Self& x) const { return !operator==(x); } 127 128 inline const Interval *operator*() const { return IntStack.top().first; } 129 inline Interval *operator*() { return IntStack.top().first; } 130 inline const Interval *operator->() const { return operator*(); } 131 inline Interval *operator->() { return operator*(); } 132 133 _Self& operator++() { // Preincrement 134 assert(!IntStack.empty() && "Attempting to use interval iterator at end!"); 135 do { 136 // All of the intervals on the stack have been visited. Try visiting 137 // their successors now. 138 Interval::succ_iterator &SuccIt = IntStack.top().second, 139 EndIt = succ_end(IntStack.top().first); 140 while (SuccIt != EndIt) { // Loop over all interval succs 141 bool Done = ProcessInterval(getSourceGraphNode(OrigContainer, *SuccIt)); 142 ++SuccIt; // Increment iterator 143 if (Done) return *this; // Found a new interval! Use it! 144 } 145 146 // Free interval memory... if necessary 147 if (IOwnMem) delete IntStack.top().first; 148 149 // We ran out of successors for this interval... pop off the stack 150 IntStack.pop(); 151 } while (!IntStack.empty()); 152 153 return *this; 154 } 155 inline _Self operator++(int) { // Postincrement 156 _Self tmp = *this; ++*this; return tmp; 157 } 158 159private: 160 // ProcessInterval - This method is used during the construction of the 161 // interval graph. It walks through the source graph, recursively creating 162 // an interval per invokation until the entire graph is covered. This uses 163 // the ProcessNode method to add all of the nodes to the interval. 164 // 165 // This method is templated because it may operate on two different source 166 // graphs: a basic block graph, or a preexisting interval graph. 167 // 168 bool ProcessInterval(NodeTy *Node) { 169 BasicBlock *Header = getNodeHeader(Node); 170 if (Visited.count(Header)) return false; 171 172 Interval *Int = new Interval(Header); 173 Visited.insert(Header); // The header has now been visited! 174 175 // Check all of our successors to see if they are in the interval... 176 for (typename GT::ChildIteratorType I = GT::child_begin(Node), 177 E = GT::child_end(Node); I != E; ++I) 178 ProcessNode(Int, getSourceGraphNode(OrigContainer, *I)); 179 180 IntStack.push(std::make_pair(Int, succ_begin(Int))); 181 return true; 182 } 183 184 // ProcessNode - This method is called by ProcessInterval to add nodes to the 185 // interval being constructed, and it is also called recursively as it walks 186 // the source graph. A node is added to the current interval only if all of 187 // its predecessors are already in the graph. This also takes care of keeping 188 // the successor set of an interval up to date. 189 // 190 // This method is templated because it may operate on two different source 191 // graphs: a basic block graph, or a preexisting interval graph. 192 // 193 void ProcessNode(Interval *Int, NodeTy *Node) { 194 assert(Int && "Null interval == bad!"); 195 assert(Node && "Null Node == bad!"); 196 197 BasicBlock *NodeHeader = getNodeHeader(Node); 198 199 if (Visited.count(NodeHeader)) { // Node already been visited? 200 if (Int->contains(NodeHeader)) { // Already in this interval... 201 return; 202 } else { // In other interval, add as successor 203 if (!Int->isSuccessor(NodeHeader)) // Add only if not already in set 204 Int->Successors.push_back(NodeHeader); 205 } 206 } else { // Otherwise, not in interval yet 207 for (typename IGT::ChildIteratorType I = IGT::child_begin(Node), 208 E = IGT::child_end(Node); I != E; ++I) { 209 if (!Int->contains(*I)) { // If pred not in interval, we can't be 210 if (!Int->isSuccessor(NodeHeader)) // Add only if not already in set 211 Int->Successors.push_back(NodeHeader); 212 return; // See you later 213 } 214 } 215 216 // If we get here, then all of the predecessors of BB are in the interval 217 // already. In this case, we must add BB to the interval! 218 addNodeToInterval(Int, Node); 219 Visited.insert(NodeHeader); // The node has now been visited! 220 221 if (Int->isSuccessor(NodeHeader)) { 222 // If we were in the successor list from before... remove from succ list 223 Int->Successors.erase(std::remove(Int->Successors.begin(), 224 Int->Successors.end(), NodeHeader), 225 Int->Successors.end()); 226 } 227 228 // Now that we have discovered that Node is in the interval, perhaps some 229 // of its successors are as well? 230 for (typename GT::ChildIteratorType It = GT::child_begin(Node), 231 End = GT::child_end(Node); It != End; ++It) 232 ProcessNode(Int, getSourceGraphNode(OrigContainer, *It)); 233 } 234 } 235}; 236 237typedef IntervalIterator<BasicBlock, Function> function_interval_iterator; 238typedef IntervalIterator<Interval, IntervalPartition> interval_part_interval_iterator; 239 240 241inline function_interval_iterator intervals_begin(Function *F, 242 bool DeleteInts = true) { 243 return function_interval_iterator(F, DeleteInts); 244} 245inline function_interval_iterator intervals_end(Function *) { 246 return function_interval_iterator(); 247} 248 249inline interval_part_interval_iterator 250 intervals_begin(IntervalPartition &IP, bool DeleteIntervals = true) { 251 return interval_part_interval_iterator(IP, DeleteIntervals); 252} 253 254inline interval_part_interval_iterator intervals_end(IntervalPartition &IP) { 255 return interval_part_interval_iterator(); 256} 257 258} // End llvm namespace 259 260#endif 261