1 //===- LiveDebugVariables.h - Tracking debug info variables ----*- 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 LiveDebugVariables analysis.
11 //
12 // The analysis removes DBG_VALUE instructions for virtual registers and tracks
13 // live user variables in a data structure that can be updated during register
14 // allocation.
15 //
16 // After register allocation new DBG_VALUE instructions are emitted to reflect
17 // the new locations of user variables.
18 //
19 //===----------------------------------------------------------------------===//
20 
21 #ifndef LLVM_CODEGEN_LIVEDEBUGVARIABLES_H
22 #define LLVM_CODEGEN_LIVEDEBUGVARIABLES_H
23 
24 #include "llvm/ADT/ArrayRef.h"
25 #include "llvm/CodeGen/MachineFunctionPass.h"
26 
27 namespace llvm {
28 
29 class LiveInterval;
30 class VirtRegMap;
31 
32 class LiveDebugVariables : public MachineFunctionPass {
33   void *pImpl;
34   /// Whether emitDebugValues is called.
35   bool EmitDone;
36   /// Whether the machine function is modified during the pass.
37   bool ModifiedMF;
38 public:
39   static char ID; // Pass identification, replacement for typeid
40 
41   LiveDebugVariables();
42   ~LiveDebugVariables();
43 
44   /// renameRegister - Move any user variables in OldReg to NewReg:SubIdx.
45   /// @param OldReg Old virtual register that is going away.
46   /// @param NewReg New register holding the user variables.
47   /// @param SubIdx If NewReg is a virtual register, SubIdx may indicate a sub-
48   ///               register.
49   void renameRegister(unsigned OldReg, unsigned NewReg, unsigned SubIdx);
50 
51   /// splitRegister - Move any user variables in OldReg to the live ranges in
52   /// NewRegs where they are live. Mark the values as unavailable where no new
53   /// register is live.
54   void splitRegister(unsigned OldReg, ArrayRef<LiveInterval*> NewRegs);
55 
56   /// emitDebugValues - Emit new DBG_VALUE instructions reflecting the changes
57   /// that happened during register allocation.
58   /// @param VRM Rename virtual registers according to map.
59   void emitDebugValues(VirtRegMap *VRM);
60 
61   /// dump - Print data structures to dbgs().
62   void dump();
63 
64 private:
65 
66   virtual bool runOnMachineFunction(MachineFunction &);
67   virtual void releaseMemory();
68   virtual void getAnalysisUsage(AnalysisUsage &) const;
69 
70 };
71 
72 } // namespace llvm
73 
74 #endif // LLVM_CODEGEN_LIVEDEBUGVARIABLES_H
75