src/llvm/lib/CodeGen/PrologEpilogInserter.h

   1 //===-- PrologEpilogInserter.h - Prolog/Epilog code insertion -*- 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 pass is responsible for finalizing the functions frame layout, saving
  11 // callee saved registers, and for emitting prolog & epilog code for the
  12 // function.
  13 //
  14 // This pass must be run after register allocation.  After this pass is
  15 // executed, it is illegal to construct MO_FrameIndex operands.
  16 //
  17 //===----------------------------------------------------------------------===//
  18
  19 #ifndef LLVM_LIB_CODEGEN_PROLOGEPILOGINSERTER_H
  20 #define LLVM_LIB_CODEGEN_PROLOGEPILOGINSERTER_H
  21
  22 #include "llvm/ADT/DenseMap.h"
  23 #include "llvm/ADT/SparseBitVector.h"
  24 #include "llvm/CodeGen/MachineFunctionPass.h"
  25 #include "llvm/CodeGen/MachineLoopInfo.h"
  26 #include "llvm/CodeGen/Passes.h"
  27 #include "llvm/Target/TargetRegisterInfo.h"
  28
  29 namespace llvm {
  30   class RegScavenger;
  31   class MachineBasicBlock;
  32
  33   class PEI : public MachineFunctionPass {
  34   public:
  35     static char ID;
  36     PEI() : MachineFunctionPass(ID) {
  37       initializePEIPass(*PassRegistry::getPassRegistry());
  38     }
  39
  40     void getAnalysisUsage(AnalysisUsage &AU) const override;
  41
  42     /// runOnMachineFunction - Insert prolog/epilog code and replace abstract
  43     /// frame indexes with appropriate references.
  44     ///
  45     bool runOnMachineFunction(MachineFunction &Fn) override;
  46
  47   private:
  48     RegScavenger *RS;
  49
  50     // MinCSFrameIndex, MaxCSFrameIndex - Keeps the range of callee saved
  51     // stack frame indexes.
  52     unsigned MinCSFrameIndex, MaxCSFrameIndex;
  53
  54     // Entry and return blocks of the current function.
  55     MachineBasicBlock* EntryBlock;
  56     SmallVector<MachineBasicBlock*, 4> ReturnBlocks;
  57
  58     // Flag to control whether to use the register scavenger to resolve
  59     // frame index materialization registers. Set according to
  60     // TRI->requiresFrameIndexScavenging() for the curren function.
  61     bool FrameIndexVirtualScavenging;
  62
  63     void calculateSets(MachineFunction &Fn);
  64     void calculateCallsInformation(MachineFunction &Fn);
  65     void calculateCalleeSavedRegisters(MachineFunction &Fn);
  66     void insertCSRSpillsAndRestores(MachineFunction &Fn);
  67     void calculateFrameObjectOffsets(MachineFunction &Fn);
  68     void replaceFrameIndices(MachineFunction &Fn);
  69     void replaceFrameIndices(MachineBasicBlock *BB, MachineFunction &Fn,
  70                              int &SPAdj);
  71     void scavengeFrameVirtualRegs(MachineFunction &Fn);
  72     void insertPrologEpilogCode(MachineFunction &Fn);
  73
  74     // Convenience for recognizing return blocks.
  75     bool isReturnBlock(MachineBasicBlock* MBB);
  76   };
  77 } // End llvm namespace
  78 #endif