1 //===- IntervalPartition.h - Interval partition Calculation -----*- 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 contains the declaration of the IntervalPartition class, which 11 // calculates and represents the interval partition of a function, or a 12 // preexisting interval partition. 13 // 14 // In this way, the interval partition may be used to reduce a flow graph down 15 // to its degenerate single node interval partition (unless it is irreducible). 16 // 17 // TODO: The IntervalPartition class should take a bool parameter that tells 18 // whether it should add the "tails" of an interval to an interval itself or if 19 // they should be represented as distinct intervals. 20 // 21 //===----------------------------------------------------------------------===// 22 23 #ifndef LLVM_INTERVAL_PARTITION_H 24 #define LLVM_INTERVAL_PARTITION_H 25 26 #include "llvm/Analysis/Interval.h" 27 #include "llvm/Pass.h" 28 #include <map> 29 30 namespace llvm { 31 32 //===----------------------------------------------------------------------===// 33 // 34 // IntervalPartition - This class builds and holds an "interval partition" for 35 // a function. This partition divides the control flow graph into a set of 36 // maximal intervals, as defined with the properties above. Intuitively, a 37 // BasicBlock is a (possibly nonexistent) loop with a "tail" of non looping 38 // nodes following it. 39 // 40 class IntervalPartition : public FunctionPass { 41 typedef std::map<BasicBlock*, Interval*> IntervalMapTy; 42 IntervalMapTy IntervalMap; 43 44 typedef std::vector<Interval*> IntervalListTy; 45 Interval *RootInterval; 46 std::vector<Interval*> Intervals; 47 48 public: 49 static char ID; // Pass identification, replacement for typeid 50 51 IntervalPartition() : FunctionPass(ID), RootInterval(0) { 52 initializeIntervalPartitionPass(*PassRegistry::getPassRegistry()); 53 } 54 55 // run - Calculate the interval partition for this function 56 virtual bool runOnFunction(Function &F); 57 58 // IntervalPartition ctor - Build a reduced interval partition from an 59 // existing interval graph. This takes an additional boolean parameter to 60 // distinguish it from a copy constructor. Always pass in false for now. 61 // 62 IntervalPartition(IntervalPartition &I, bool); 63 64 // print - Show contents in human readable format... 65 virtual void print(raw_ostream &O, const Module* = 0) const; 66 67 // getRootInterval() - Return the root interval that contains the starting 68 // block of the function. 69 inline Interval *getRootInterval() { return RootInterval; } 70 71 // isDegeneratePartition() - Returns true if the interval partition contains 72 // a single interval, and thus cannot be simplified anymore. 73 bool isDegeneratePartition() { return Intervals.size() == 1; } 74 75 // TODO: isIrreducible - look for triangle graph. 76 77 // getBlockInterval - Return the interval that a basic block exists in. 78 inline Interval *getBlockInterval(BasicBlock *BB) { 79 IntervalMapTy::iterator I = IntervalMap.find(BB); 80 return I != IntervalMap.end() ? I->second : 0; 81 } 82 83 // getAnalysisUsage - Implement the Pass API 84 virtual void getAnalysisUsage(AnalysisUsage &AU) const { 85 AU.setPreservesAll(); 86 } 87 88 // Interface to Intervals vector... 89 const std::vector<Interval*> &getIntervals() const { return Intervals; } 90 91 // releaseMemory - Reset state back to before function was analyzed 92 void releaseMemory(); 93 94 private: 95 // addIntervalToPartition - Add an interval to the internal list of intervals, 96 // and then add mappings from all of the basic blocks in the interval to the 97 // interval itself (in the IntervalMap). 98 // 99 void addIntervalToPartition(Interval *I); 100 101 // updatePredecessors - Interval generation only sets the successor fields of 102 // the interval data structures. After interval generation is complete, 103 // run through all of the intervals and propagate successor info as 104 // predecessor info. 105 // 106 void updatePredecessors(Interval *Int); 107 }; 108 109 } // End llvm namespace 110 111 #endif 112
