1 //===- MachineLoopRanges.h - Ranges of machine loops -----------*- 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 provides the interface to the MachineLoopRanges analysis.
11 //
12 // Provide on-demand information about the ranges of machine instructions
13 // covered by a loop.
14 //
15 //===----------------------------------------------------------------------===//
16 
17 #ifndef LLVM_CODEGEN_MACHINELOOPRANGES_H
18 #define LLVM_CODEGEN_MACHINELOOPRANGES_H
19 
20 #include "llvm/ADT/IntervalMap.h"
21 #include "llvm/CodeGen/SlotIndexes.h"
22 
23 namespace llvm {
24 
25 class MachineLoop;
26 class MachineLoopInfo;
27 class raw_ostream;
28 
29 /// MachineLoopRange - Range information for a single loop.
30 class MachineLoopRange {
31   friend class MachineLoopRanges;
32 
33 public:
34   typedef IntervalMap<SlotIndex, unsigned, 4> Map;
35   typedef Map::Allocator Allocator;
36 
37 private:
38   /// The mapped loop.
39   const MachineLoop *const Loop;
40 
41   /// Map intervals to a bit mask.
42   /// Bit 0 = inside loop block.
43   Map Intervals;
44 
45   /// Loop area as measured by SlotIndex::distance.
46   unsigned Area;
47 
48   /// Create a MachineLoopRange, only accessible to MachineLoopRanges.
49   MachineLoopRange(const MachineLoop*, Allocator&, SlotIndexes&);
50 
51 public:
52   /// getLoop - Return the mapped machine loop.
getLoop()53   const MachineLoop *getLoop() const { return Loop; }
54 
55   /// overlaps - Return true if this loop overlaps the given range of machine
56   /// inteructions.
57   bool overlaps(SlotIndex Start, SlotIndex Stop);
58 
59   /// getNumber - Return the loop number. This is the same as the number of the
60   /// header block.
61   unsigned getNumber() const;
62 
63   /// getArea - Return the loop area. This number is approximately proportional
64   /// to the number of instructions in the loop.
getArea()65   unsigned getArea() const { return Area; }
66 
67   /// getMap - Allow public read-only access for IntervalMapOverlaps.
getMap()68   const Map &getMap() { return Intervals; }
69 
70   /// print - Print loop ranges on OS.
71   void print(raw_ostream&) const;
72 
73   /// byNumber - Comparator for array_pod_sort that sorts a list of
74   /// MachineLoopRange pointers by number.
75   static int byNumber(const void*, const void*);
76 
77   /// byAreaDesc - Comparator for array_pod_sort that sorts a list of
78   /// MachineLoopRange pointers by descending area, then by number.
79   static int byAreaDesc(const void*, const void*);
80 };
81 
82 raw_ostream &operator<<(raw_ostream&, const MachineLoopRange&);
83 
84 /// MachineLoopRanges - Analysis pass that provides on-demand per-loop range
85 /// information.
86 class MachineLoopRanges : public MachineFunctionPass {
87   typedef DenseMap<const MachineLoop*, MachineLoopRange*> CacheMap;
88   typedef MachineLoopRange::Allocator MapAllocator;
89 
90   MapAllocator Allocator;
91   SlotIndexes *Indexes;
92   CacheMap Cache;
93 
94 public:
95   static char ID; // Pass identification, replacement for typeid
96 
MachineLoopRanges()97   MachineLoopRanges() : MachineFunctionPass(ID), Indexes(0) {}
~MachineLoopRanges()98   ~MachineLoopRanges() { releaseMemory(); }
99 
100   /// getLoopRange - Return the range of loop.
101   MachineLoopRange *getLoopRange(const MachineLoop *Loop);
102 
103 private:
104   virtual bool runOnMachineFunction(MachineFunction&);
105   virtual void releaseMemory();
106   virtual void getAnalysisUsage(AnalysisUsage&) const;
107 };
108 
109 
110 } // end namespace llvm
111 
112 #endif // LLVM_CODEGEN_MACHINELOOPRANGES_H
113