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      1 //===-- PPCFrameLowering.h - Define frame lowering for PowerPC --*- 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 //
     11 //===----------------------------------------------------------------------===//
     12 
     13 #ifndef POWERPC_FRAMEINFO_H
     14 #define POWERPC_FRAMEINFO_H
     15 
     16 #include "PPC.h"
     17 #include "llvm/ADT/STLExtras.h"
     18 #include "llvm/Target/TargetFrameLowering.h"
     19 #include "llvm/Target/TargetMachine.h"
     20 
     21 namespace llvm {
     22 class PPCSubtarget;
     23 
     24 class PPCFrameLowering: public TargetFrameLowering {
     25   const PPCSubtarget &Subtarget;
     26 
     27 public:
     28   PPCFrameLowering(const PPCSubtarget &STI);
     29 
     30   unsigned determineFrameLayout(MachineFunction &MF,
     31                                 bool UpdateMF = true,
     32                                 bool UseEstimate = false) const;
     33 
     34   /// emitProlog/emitEpilog - These methods insert prolog and epilog code into
     35   /// the function.
     36   void emitPrologue(MachineFunction &MF) const override;
     37   void emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
     38 
     39   bool hasFP(const MachineFunction &MF) const override;
     40   bool needsFP(const MachineFunction &MF) const;
     41   void replaceFPWithRealFP(MachineFunction &MF) const;
     42 
     43   void processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
     44                                      RegScavenger *RS = nullptr) const override;
     45   void processFunctionBeforeFrameFinalized(MachineFunction &MF,
     46                                      RegScavenger *RS = nullptr) const override;
     47   void addScavengingSpillSlot(MachineFunction &MF, RegScavenger *RS) const;
     48 
     49   bool spillCalleeSavedRegisters(MachineBasicBlock &MBB,
     50                                  MachineBasicBlock::iterator MI,
     51                                  const std::vector<CalleeSavedInfo> &CSI,
     52                                  const TargetRegisterInfo *TRI) const override;
     53 
     54   void eliminateCallFramePseudoInstr(MachineFunction &MF,
     55                                   MachineBasicBlock &MBB,
     56                                   MachineBasicBlock::iterator I) const override;
     57 
     58   bool restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
     59                                   MachineBasicBlock::iterator MI,
     60                                   const std::vector<CalleeSavedInfo> &CSI,
     61                                   const TargetRegisterInfo *TRI) const override;
     62 
     63   /// targetHandlesStackFrameRounding - Returns true if the target is
     64   /// responsible for rounding up the stack frame (probably at emitPrologue
     65   /// time).
     66   bool targetHandlesStackFrameRounding() const override { return true; }
     67 
     68   /// getReturnSaveOffset - Return the previous frame offset to save the
     69   /// return address.
     70   static unsigned getReturnSaveOffset(bool isPPC64, bool isDarwinABI) {
     71     if (isDarwinABI)
     72       return isPPC64 ? 16 : 8;
     73     // SVR4 ABI:
     74     return isPPC64 ? 16 : 4;
     75   }
     76 
     77   /// getTOCSaveOffset - Return the previous frame offset to save the
     78   /// TOC register -- 64-bit SVR4 ABI only.
     79   static unsigned getTOCSaveOffset(void) {
     80     return 40;
     81   }
     82 
     83   /// getFramePointerSaveOffset - Return the previous frame offset to save the
     84   /// frame pointer.
     85   static unsigned getFramePointerSaveOffset(bool isPPC64, bool isDarwinABI) {
     86     // For the Darwin ABI:
     87     // We cannot use the TOC save slot (offset +20) in the PowerPC linkage area
     88     // for saving the frame pointer (if needed.)  While the published ABI has
     89     // not used this slot since at least MacOSX 10.2, there is older code
     90     // around that does use it, and that needs to continue to work.
     91     if (isDarwinABI)
     92       return isPPC64 ? -8U : -4U;
     93 
     94     // SVR4 ABI: First slot in the general register save area.
     95     return isPPC64 ? -8U : -4U;
     96   }
     97 
     98   /// getBasePointerSaveOffset - Return the previous frame offset to save the
     99   /// base pointer.
    100   static unsigned getBasePointerSaveOffset(bool isPPC64, bool isDarwinABI) {
    101     if (isDarwinABI)
    102       return isPPC64 ? -16U : -8U;
    103 
    104     // SVR4 ABI: First slot in the general register save area.
    105     return isPPC64 ? -16U : -8U;
    106   }
    107 
    108   /// getLinkageSize - Return the size of the PowerPC ABI linkage area.
    109   ///
    110   static unsigned getLinkageSize(bool isPPC64, bool isDarwinABI) {
    111     if (isDarwinABI || isPPC64)
    112       return 6 * (isPPC64 ? 8 : 4);
    113 
    114     // SVR4 ABI:
    115     return 8;
    116   }
    117 
    118   const SpillSlot *
    119   getCalleeSavedSpillSlots(unsigned &NumEntries) const override;
    120 };
    121 } // End llvm namespace
    122 
    123 #endif
    124