lib/CodeGen/LiveDebugVariables.h

   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