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      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/ADT/ArrayRef.h"
     25 #include "llvm/CodeGen/MachineFunctionPass.h"
     26 #include "llvm/IR/DebugInfo.h"
     27 
     28 namespace llvm {
     29 
     30 class LiveInterval;
     31 class LiveIntervals;
     32 class VirtRegMap;
     33 
     34 class LLVM_LIBRARY_VISIBILITY LiveDebugVariables : public MachineFunctionPass {
     35   void *pImpl;
     36 
     37 public:
     38   static char ID; // Pass identification, replacement for typeid
     39 
     40   LiveDebugVariables();
     41   ~LiveDebugVariables() override;
     42 
     43   /// renameRegister - Move any user variables in OldReg to NewReg:SubIdx.
     44   /// @param OldReg Old virtual register that is going away.
     45   /// @param NewReg New register holding the user variables.
     46   /// @param SubIdx If NewReg is a virtual register, SubIdx may indicate a sub-
     47   ///               register.
     48   void renameRegister(unsigned OldReg, unsigned NewReg, unsigned SubIdx);
     49 
     50   /// splitRegister - Move any user variables in OldReg to the live ranges in
     51   /// NewRegs where they are live. Mark the values as unavailable where no new
     52   /// register is live.
     53   void splitRegister(unsigned OldReg, ArrayRef<unsigned> NewRegs,
     54                      LiveIntervals &LIS);
     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   bool runOnMachineFunction(MachineFunction &) override;
     67   void releaseMemory() override;
     68   void getAnalysisUsage(AnalysisUsage &) const override;
     69   bool doInitialization(Module &) override;
     70 
     71 };
     72 
     73 } // namespace llvm
     74 
     75 #endif
     76