1//===- IntervalIterator.h - Interval Iterator Declaration -------*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// 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_ANALYSIS_INTERVALITERATOR_H 34#define LLVM_ANALYSIS_INTERVALITERATOR_H 35 36#include "llvm/Analysis/IntervalPartition.h" 37#include "llvm/IR/Function.h" 38#include "llvm/Support/CFG.h" 39#include <algorithm> 40#include <set> 41#include <vector> 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::vector<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 IntervalIterator<NodeTy, OrigContainer_t> _Self; 98 typedef std::forward_iterator_tag iterator_category; 99 100 IntervalIterator() {} // End iterator, empty stack 101 IntervalIterator(Function *M, bool OwnMemory) : IOwnMem(OwnMemory) { 102 OrigContainer = M; 103 if (!ProcessInterval(&M->front())) { 104 llvm_unreachable("ProcessInterval should never fail for first interval!"); 105 } 106 } 107 108 IntervalIterator(IntervalPartition &IP, bool OwnMemory) : IOwnMem(OwnMemory) { 109 OrigContainer = &IP; 110 if (!ProcessInterval(IP.getRootInterval())) { 111 llvm_unreachable("ProcessInterval should never fail for first interval!"); 112 } 113 } 114 115 inline ~IntervalIterator() { 116 if (IOwnMem) 117 while (!IntStack.empty()) { 118 delete operator*(); 119 IntStack.pop_back(); 120 } 121 } 122 123 inline bool operator==(const _Self& x) const { return IntStack == x.IntStack;} 124 inline bool operator!=(const _Self& x) const { return !operator==(x); } 125 126 inline const Interval *operator*() const { return IntStack.back().first; } 127 inline Interval *operator*() { return IntStack.back().first; } 128 inline const Interval *operator->() const { return operator*(); } 129 inline Interval *operator->() { return operator*(); } 130 131 _Self& operator++() { // Preincrement 132 assert(!IntStack.empty() && "Attempting to use interval iterator at end!"); 133 do { 134 // All of the intervals on the stack have been visited. Try visiting 135 // their successors now. 136 Interval::succ_iterator &SuccIt = IntStack.back().second, 137 EndIt = succ_end(IntStack.back().first); 138 while (SuccIt != EndIt) { // Loop over all interval succs 139 bool Done = ProcessInterval(getSourceGraphNode(OrigContainer, *SuccIt)); 140 ++SuccIt; // Increment iterator 141 if (Done) return *this; // Found a new interval! Use it! 142 } 143 144 // Free interval memory... if necessary 145 if (IOwnMem) delete IntStack.back().first; 146 147 // We ran out of successors for this interval... pop off the stack 148 IntStack.pop_back(); 149 } while (!IntStack.empty()); 150 151 return *this; 152 } 153 inline _Self operator++(int) { // Postincrement 154 _Self tmp = *this; ++*this; return tmp; 155 } 156 157private: 158 // ProcessInterval - This method is used during the construction of the 159 // interval graph. It walks through the source graph, recursively creating 160 // an interval per invocation until the entire graph is covered. This uses 161 // the ProcessNode method to add all of the nodes to the interval. 162 // 163 // This method is templated because it may operate on two different source 164 // graphs: a basic block graph, or a preexisting interval graph. 165 // 166 bool ProcessInterval(NodeTy *Node) { 167 BasicBlock *Header = getNodeHeader(Node); 168 if (Visited.count(Header)) return false; 169 170 Interval *Int = new Interval(Header); 171 Visited.insert(Header); // The header has now been visited! 172 173 // Check all of our successors to see if they are in the interval... 174 for (typename GT::ChildIteratorType I = GT::child_begin(Node), 175 E = GT::child_end(Node); I != E; ++I) 176 ProcessNode(Int, getSourceGraphNode(OrigContainer, *I)); 177 178 IntStack.push_back(std::make_pair(Int, succ_begin(Int))); 179 return true; 180 } 181 182 // ProcessNode - This method is called by ProcessInterval to add nodes to the 183 // interval being constructed, and it is also called recursively as it walks 184 // the source graph. A node is added to the current interval only if all of 185 // its predecessors are already in the graph. This also takes care of keeping 186 // the successor set of an interval up to date. 187 // 188 // This method is templated because it may operate on two different source 189 // graphs: a basic block graph, or a preexisting interval graph. 190 // 191 void ProcessNode(Interval *Int, NodeTy *Node) { 192 assert(Int && "Null interval == bad!"); 193 assert(Node && "Null Node == bad!"); 194 195 BasicBlock *NodeHeader = getNodeHeader(Node); 196 197 if (Visited.count(NodeHeader)) { // Node already been visited? 198 if (Int->contains(NodeHeader)) { // Already in this interval... 199 return; 200 } else { // In other interval, add as successor 201 if (!Int->isSuccessor(NodeHeader)) // Add only if not already in set 202 Int->Successors.push_back(NodeHeader); 203 } 204 } else { // Otherwise, not in interval yet 205 for (typename IGT::ChildIteratorType I = IGT::child_begin(Node), 206 E = IGT::child_end(Node); I != E; ++I) { 207 if (!Int->contains(*I)) { // If pred not in interval, we can't be 208 if (!Int->isSuccessor(NodeHeader)) // Add only if not already in set 209 Int->Successors.push_back(NodeHeader); 210 return; // See you later 211 } 212 } 213 214 // If we get here, then all of the predecessors of BB are in the interval 215 // already. In this case, we must add BB to the interval! 216 addNodeToInterval(Int, Node); 217 Visited.insert(NodeHeader); // The node has now been visited! 218 219 if (Int->isSuccessor(NodeHeader)) { 220 // If we were in the successor list from before... remove from succ list 221 Int->Successors.erase(std::remove(Int->Successors.begin(), 222 Int->Successors.end(), NodeHeader), 223 Int->Successors.end()); 224 } 225 226 // Now that we have discovered that Node is in the interval, perhaps some 227 // of its successors are as well? 228 for (typename GT::ChildIteratorType It = GT::child_begin(Node), 229 End = GT::child_end(Node); It != End; ++It) 230 ProcessNode(Int, getSourceGraphNode(OrigContainer, *It)); 231 } 232 } 233}; 234 235typedef IntervalIterator<BasicBlock, Function> function_interval_iterator; 236typedef IntervalIterator<Interval, IntervalPartition> 237 interval_part_interval_iterator; 238 239 240inline function_interval_iterator intervals_begin(Function *F, 241 bool DeleteInts = true) { 242 return function_interval_iterator(F, DeleteInts); 243} 244inline function_interval_iterator intervals_end(Function *) { 245 return function_interval_iterator(); 246} 247 248inline interval_part_interval_iterator 249 intervals_begin(IntervalPartition &IP, bool DeleteIntervals = true) { 250 return interval_part_interval_iterator(IP, DeleteIntervals); 251} 252 253inline interval_part_interval_iterator intervals_end(IntervalPartition &IP) { 254 return interval_part_interval_iterator(); 255} 256 257} // End llvm namespace 258 259#endif 260