IntervalPartition.h revision 208954
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 30namespace 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// 40class 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 48public: 49 static char ID; // Pass identification, replacement for typeid 50 51 IntervalPartition() : FunctionPass(&ID), RootInterval(0) {} 52 53 // run - Calculate the interval partition for this function 54 virtual bool runOnFunction(Function &F); 55 56 // IntervalPartition ctor - Build a reduced interval partition from an 57 // existing interval graph. This takes an additional boolean parameter to 58 // distinguish it from a copy constructor. Always pass in false for now. 59 // 60 IntervalPartition(IntervalPartition &I, bool); 61 62 // print - Show contents in human readable format... 63 virtual void print(raw_ostream &O, const Module* = 0) const; 64 65 // getRootInterval() - Return the root interval that contains the starting 66 // block of the function. 67 inline Interval *getRootInterval() { return RootInterval; } 68 69 // isDegeneratePartition() - Returns true if the interval partition contains 70 // a single interval, and thus cannot be simplified anymore. 71 bool isDegeneratePartition() { return Intervals.size() == 1; } 72 73 // TODO: isIrreducible - look for triangle graph. 74 75 // getBlockInterval - Return the interval that a basic block exists in. 76 inline Interval *getBlockInterval(BasicBlock *BB) { 77 IntervalMapTy::iterator I = IntervalMap.find(BB); 78 return I != IntervalMap.end() ? I->second : 0; 79 } 80 81 // getAnalysisUsage - Implement the Pass API 82 virtual void getAnalysisUsage(AnalysisUsage &AU) const { 83 AU.setPreservesAll(); 84 } 85 86 // Interface to Intervals vector... 87 const std::vector<Interval*> &getIntervals() const { return Intervals; } 88 89 // releaseMemory - Reset state back to before function was analyzed 90 void releaseMemory(); 91 92private: 93 // addIntervalToPartition - Add an interval to the internal list of intervals, 94 // and then add mappings from all of the basic blocks in the interval to the 95 // interval itself (in the IntervalMap). 96 // 97 void addIntervalToPartition(Interval *I); 98 99 // updatePredecessors - Interval generation only sets the successor fields of 100 // the interval data structures. After interval generation is complete, 101 // run through all of the intervals and propagate successor info as 102 // predecessor info. 103 // 104 void updatePredecessors(Interval *Int); 105}; 106 107} // End llvm namespace 108 109#endif 110