1//===-- X86TargetFrameLowering.h - Define frame lowering for X86 -*- 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 class implements X86-specific bits of TargetFrameLowering class.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef X86_FRAMELOWERING_H
15#define X86_FRAMELOWERING_H
16
17#include "X86Subtarget.h"
18#include "llvm/MC/MCDwarf.h"
19#include "llvm/Target/TargetFrameLowering.h"
20
21namespace llvm {
22
23namespace CU {
24
25  /// Compact unwind encoding values.
26  enum CompactUnwindEncodings {
27    /// [RE]BP based frame where [RE]BP is pused on the stack immediately after
28    /// the return address, then [RE]SP is moved to [RE]BP.
29    UNWIND_MODE_BP_FRAME                   = 0x01000000,
30
31    /// A frameless function with a small constant stack size.
32    UNWIND_MODE_STACK_IMMD                 = 0x02000000,
33
34    /// A frameless function with a large constant stack size.
35    UNWIND_MODE_STACK_IND                  = 0x03000000,
36
37    /// No compact unwind encoding is available.
38    UNWIND_MODE_DWARF                      = 0x04000000,
39
40    /// Mask for encoding the frame registers.
41    UNWIND_BP_FRAME_REGISTERS              = 0x00007FFF,
42
43    /// Mask for encoding the frameless registers.
44    UNWIND_FRAMELESS_STACK_REG_PERMUTATION = 0x000003FF
45  };
46
47} // end CU namespace
48
49class MCSymbol;
50class X86TargetMachine;
51
52class X86FrameLowering : public TargetFrameLowering {
53  const X86TargetMachine &TM;
54  const X86Subtarget &STI;
55public:
56  explicit X86FrameLowering(const X86TargetMachine &tm, const X86Subtarget &sti)
57    : TargetFrameLowering(StackGrowsDown,
58                          sti.getStackAlignment(),
59                          (sti.is64Bit() ? -8 : -4)),
60      TM(tm), STI(sti) {
61  }
62
63  void emitCalleeSavedFrameMoves(MachineFunction &MF, MCSymbol *Label,
64                                 unsigned FramePtr) const;
65
66  /// emitProlog/emitEpilog - These methods insert prolog and epilog code into
67  /// the function.
68  void emitPrologue(MachineFunction &MF) const;
69  void emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const;
70
71  void adjustForSegmentedStacks(MachineFunction &MF) const;
72
73  void adjustForHiPEPrologue(MachineFunction &MF) const;
74
75  void processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
76                                            RegScavenger *RS = NULL) const;
77
78  bool spillCalleeSavedRegisters(MachineBasicBlock &MBB,
79                                 MachineBasicBlock::iterator MI,
80                                 const std::vector<CalleeSavedInfo> &CSI,
81                                 const TargetRegisterInfo *TRI) const;
82
83  bool restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
84                                   MachineBasicBlock::iterator MI,
85                                   const std::vector<CalleeSavedInfo> &CSI,
86                                   const TargetRegisterInfo *TRI) const;
87
88  bool hasFP(const MachineFunction &MF) const;
89  bool hasReservedCallFrame(const MachineFunction &MF) const;
90
91  int getFrameIndexOffset(const MachineFunction &MF, int FI) const;
92  int getFrameIndexReference(const MachineFunction &MF, int FI,
93                             unsigned &FrameReg) const;
94  uint32_t getCompactUnwindEncoding(MachineFunction &MF) const;
95
96  void eliminateCallFramePseudoInstr(MachineFunction &MF,
97                                     MachineBasicBlock &MBB,
98                                     MachineBasicBlock::iterator MI) const;
99};
100
101} // End llvm namespace
102
103#endif
104