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_LIB_CODEGEN_LIVEDEBUGVARIABLES_H
22 #define LLVM_LIB_CODEGEN_LIVEDEBUGVARIABLES_H
23 
24 #include "llvm/CodeGen/MachineFunctionPass.h"
25 #include "llvm/Support/Compiler.h"
26 
27 namespace llvm {
28 
29 template <typename T> class ArrayRef;
30 class LiveIntervals;
31 class VirtRegMap;
32 
33 class LLVM_LIBRARY_VISIBILITY LiveDebugVariables : public MachineFunctionPass {
34   void *pImpl = nullptr;
35 
36 public:
37   static char ID; // Pass identification, replacement for typeid
38 
39   LiveDebugVariables();
40   ~LiveDebugVariables() override;
41 
42   /// renameRegister - Move any user variables in OldReg to NewReg:SubIdx.
43   /// @param OldReg Old virtual register that is going away.
44   /// @param NewReg New register holding the user variables.
45   /// @param SubIdx If NewReg is a virtual register, SubIdx may indicate a sub-
46   ///               register.
47   void renameRegister(unsigned OldReg, unsigned NewReg, unsigned SubIdx);
48 
49   /// splitRegister - Move any user variables in OldReg to the live ranges in
50   /// NewRegs where they are live. Mark the values as unavailable where no new
51   /// register is live.
52   void splitRegister(unsigned OldReg, ArrayRef<unsigned> NewRegs,
53                      LiveIntervals &LIS);
54 
55   /// emitDebugValues - Emit new DBG_VALUE instructions reflecting the changes
56   /// that happened during register allocation.
57   /// @param VRM Rename virtual registers according to map.
58   void emitDebugValues(VirtRegMap *VRM);
59 
60   /// dump - Print data structures to dbgs().
61   void dump() const;
62 
63 private:
64   bool runOnMachineFunction(MachineFunction &) override;
65   void releaseMemory() override;
66   void getAnalysisUsage(AnalysisUsage &) const override;
67   bool doInitialization(Module &) override;
68 };
69 
70 } // end namespace llvm
71 
72 #endif // LLVM_LIB_CODEGEN_LIVEDEBUGVARIABLES_H
73