LiveStackAnalysis.h revision 206083 
1//===-- LiveStackAnalysis.h - Live Stack Slot Analysis ----------*- 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 implements the live stack slot analysis pass. It is analogous to
11// live interval analysis except it's analyzing liveness of stack slots rather
12// than registers.
13//
14//===----------------------------------------------------------------------===//
15
16#ifndef LLVM_CODEGEN_LIVESTACK_ANALYSIS_H
17#define LLVM_CODEGEN_LIVESTACK_ANALYSIS_H
18
19#include "llvm/CodeGen/MachineFunctionPass.h"
20#include "llvm/CodeGen/LiveInterval.h"
21#include "llvm/Target/TargetRegisterInfo.h"
22#include "llvm/Support/Allocator.h"
23#include <map>
24
25namespace llvm {
26
27  class LiveStacks : public MachineFunctionPass {
28    /// Special pool allocator for VNInfo's (LiveInterval val#).
29    ///
30    VNInfo::Allocator VNInfoAllocator;
31
32    /// S2IMap - Stack slot indices to live interval mapping.
33    ///
34    typedef std::map<int, LiveInterval> SS2IntervalMap;
35    SS2IntervalMap S2IMap;
36
37    /// S2RCMap - Stack slot indices to register class mapping.
38    std::map<int, const TargetRegisterClass*> S2RCMap;
39
40  public:
41    static char ID; // Pass identification, replacement for typeid
42    LiveStacks() : MachineFunctionPass(&ID) {}
43
44    typedef SS2IntervalMap::iterator iterator;
45    typedef SS2IntervalMap::const_iterator const_iterator;
46    const_iterator begin() const { return S2IMap.begin(); }
47    const_iterator end() const { return S2IMap.end(); }
48    iterator begin() { return S2IMap.begin(); }
49    iterator end() { return S2IMap.end(); }
50
51    unsigned getNumIntervals() const { return (unsigned)S2IMap.size(); }
52
53    LiveInterval &getOrCreateInterval(int Slot, const TargetRegisterClass *RC) {
54      assert(Slot >= 0 && "Spill slot indice must be >= 0");
55      SS2IntervalMap::iterator I = S2IMap.find(Slot);
56      if (I == S2IMap.end()) {
57        I = S2IMap.insert(I,std::make_pair(Slot, LiveInterval(Slot,0.0F,true)));
58        S2RCMap.insert(std::make_pair(Slot, RC));
59      } else {
60        // Use the largest common subclass register class.
61        const TargetRegisterClass *OldRC = S2RCMap[Slot];
62        S2RCMap[Slot] = getCommonSubClass(OldRC, RC);
63      }
64      return I->second;
65    }
66
67    LiveInterval &getInterval(int Slot) {
68      assert(Slot >= 0 && "Spill slot indice must be >= 0");
69      SS2IntervalMap::iterator I = S2IMap.find(Slot);
70      assert(I != S2IMap.end() && "Interval does not exist for stack slot");
71      return I->second;
72    }
73
74    const LiveInterval &getInterval(int Slot) const {
75      assert(Slot >= 0 && "Spill slot indice must be >= 0");
76      SS2IntervalMap::const_iterator I = S2IMap.find(Slot);
77      assert(I != S2IMap.end() && "Interval does not exist for stack slot");
78      return I->second;
79    }
80
81    bool hasInterval(int Slot) const {
82      return S2IMap.count(Slot);
83    }
84
85    const TargetRegisterClass *getIntervalRegClass(int Slot) const {
86      assert(Slot >= 0 && "Spill slot indice must be >= 0");
87      std::map<int, const TargetRegisterClass*>::const_iterator
88        I = S2RCMap.find(Slot);
89      assert(I != S2RCMap.end() &&
90             "Register class info does not exist for stack slot");
91      return I->second;
92    }
93
94    VNInfo::Allocator& getVNInfoAllocator() { return VNInfoAllocator; }
95
96    virtual void getAnalysisUsage(AnalysisUsage &AU) const;
97    virtual void releaseMemory();
98
99    /// runOnMachineFunction - pass entry point
100    virtual bool runOnMachineFunction(MachineFunction&);
101
102    /// print - Implement the dump method.
103    virtual void print(raw_ostream &O, const Module* = 0) const;
104  };
105}
106
107#endif /* LLVM_CODEGEN_LIVESTACK_ANALYSIS_H */
108