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 LLVM_LIB_TARGET_X86_X86FRAMELOWERING_H
15#define LLVM_LIB_TARGET_X86_X86FRAMELOWERING_H
16
17#include "llvm/Target/TargetFrameLowering.h"
18
19namespace llvm {
20
21class MachineInstrBuilder;
22class MCCFIInstruction;
23class X86Subtarget;
24class X86RegisterInfo;
25
26class X86FrameLowering : public TargetFrameLowering {
27public:
28  X86FrameLowering(const X86Subtarget &STI, unsigned StackAlignOverride);
29
30  // Cached subtarget predicates.
31
32  const X86Subtarget &STI;
33  const TargetInstrInfo &TII;
34  const X86RegisterInfo *TRI;
35
36  unsigned SlotSize;
37
38  /// Is64Bit implies that x86_64 instructions are available.
39  bool Is64Bit;
40
41  bool IsLP64;
42
43  /// True if the 64-bit frame or stack pointer should be used. True for most
44  /// 64-bit targets with the exception of x32. If this is false, 32-bit
45  /// instruction operands should be used to manipulate StackPtr and FramePtr.
46  bool Uses64BitFramePtr;
47
48  unsigned StackPtr;
49
50  /// Emit target stack probe code. This is required for all
51  /// large stack allocations on Windows. The caller is required to materialize
52  /// the number of bytes to probe in RAX/EAX. Returns instruction just
53  /// after the expansion.
54  MachineInstr *emitStackProbe(MachineFunction &MF, MachineBasicBlock &MBB,
55                               MachineBasicBlock::iterator MBBI, DebugLoc DL,
56                               bool InProlog) const;
57
58  /// Replace a StackProbe inline-stub with the actual probe code inline.
59  void inlineStackProbe(MachineFunction &MF,
60                        MachineBasicBlock &PrologMBB) const override;
61
62  void emitCalleeSavedFrameMoves(MachineBasicBlock &MBB,
63                                 MachineBasicBlock::iterator MBBI,
64                                 DebugLoc DL) const;
65
66  /// emitProlog/emitEpilog - These methods insert prolog and epilog code into
67  /// the function.
68  void emitPrologue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
69  void emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
70
71  void adjustForSegmentedStacks(MachineFunction &MF,
72                                MachineBasicBlock &PrologueMBB) const override;
73
74  void adjustForHiPEPrologue(MachineFunction &MF,
75                             MachineBasicBlock &PrologueMBB) const override;
76
77  void determineCalleeSaves(MachineFunction &MF, BitVector &SavedRegs,
78                            RegScavenger *RS = nullptr) const override;
79
80  bool
81  assignCalleeSavedSpillSlots(MachineFunction &MF,
82                              const TargetRegisterInfo *TRI,
83                              std::vector<CalleeSavedInfo> &CSI) const override;
84
85  bool spillCalleeSavedRegisters(MachineBasicBlock &MBB,
86                                 MachineBasicBlock::iterator MI,
87                                 const std::vector<CalleeSavedInfo> &CSI,
88                                 const TargetRegisterInfo *TRI) const override;
89
90  bool restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
91                                  MachineBasicBlock::iterator MI,
92                                  const std::vector<CalleeSavedInfo> &CSI,
93                                  const TargetRegisterInfo *TRI) const override;
94
95  bool hasFP(const MachineFunction &MF) const override;
96  bool hasReservedCallFrame(const MachineFunction &MF) const override;
97  bool canSimplifyCallFramePseudos(const MachineFunction &MF) const override;
98  bool needsFrameIndexResolution(const MachineFunction &MF) const override;
99
100  int getFrameIndexReference(const MachineFunction &MF, int FI,
101                             unsigned &FrameReg) const override;
102
103  int getFrameIndexReferenceFromSP(const MachineFunction &MF, int FI,
104                                   unsigned &FrameReg) const override;
105
106  void eliminateCallFramePseudoInstr(MachineFunction &MF,
107                                 MachineBasicBlock &MBB,
108                                 MachineBasicBlock::iterator MI) const override;
109
110  unsigned getWinEHParentFrameOffset(const MachineFunction &MF) const override;
111
112  void processFunctionBeforeFrameFinalized(MachineFunction &MF,
113                                           RegScavenger *RS) const override;
114
115  /// Check the instruction before/after the passed instruction. If
116  /// it is an ADD/SUB/LEA instruction it is deleted argument and the
117  /// stack adjustment is returned as a positive value for ADD/LEA and
118  /// a negative for SUB.
119  int mergeSPUpdates(MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI,
120                     bool doMergeWithPrevious) const;
121
122  /// Emit a series of instructions to increment / decrement the stack
123  /// pointer by a constant value.
124  void emitSPUpdate(MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI,
125                    int64_t NumBytes, bool InEpilogue) const;
126
127  /// Check that LEA can be used on SP in an epilogue sequence for \p MF.
128  bool canUseLEAForSPInEpilogue(const MachineFunction &MF) const;
129
130  /// Check whether or not the given \p MBB can be used as a epilogue
131  /// for the target.
132  /// The epilogue will be inserted before the first terminator of that block.
133  /// This method is used by the shrink-wrapping pass to decide if
134  /// \p MBB will be correctly handled by the target.
135  bool canUseAsEpilogue(const MachineBasicBlock &MBB) const override;
136
137  /// Returns true if the target will correctly handle shrink wrapping.
138  bool enableShrinkWrapping(const MachineFunction &MF) const override;
139
140  /// convertArgMovsToPushes - This method tries to convert a call sequence
141  /// that uses sub and mov instructions to put the argument onto the stack
142  /// into a series of pushes.
143  /// Returns true if the transformation succeeded, false if not.
144  bool convertArgMovsToPushes(MachineFunction &MF,
145                              MachineBasicBlock &MBB,
146                              MachineBasicBlock::iterator I,
147                              uint64_t Amount) const;
148
149  /// Wraps up getting a CFI index and building a MachineInstr for it.
150  void BuildCFI(MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI,
151                DebugLoc DL, MCCFIInstruction CFIInst) const;
152
153  /// Sets up EBP and optionally ESI based on the incoming EBP value.  Only
154  /// needed for 32-bit. Used in funclet prologues and at catchret destinations.
155  MachineBasicBlock::iterator
156  restoreWin32EHStackPointers(MachineBasicBlock &MBB,
157                              MachineBasicBlock::iterator MBBI, DebugLoc DL,
158                              bool RestoreSP = false) const;
159
160private:
161  uint64_t calculateMaxStackAlign(const MachineFunction &MF) const;
162
163  /// Emit target stack probe as a call to a helper function
164  MachineInstr *emitStackProbeCall(MachineFunction &MF, MachineBasicBlock &MBB,
165                                   MachineBasicBlock::iterator MBBI,
166                                   DebugLoc DL, bool InProlog) const;
167
168  /// Emit target stack probe as an inline sequence.
169  MachineInstr *emitStackProbeInline(MachineFunction &MF,
170                                     MachineBasicBlock &MBB,
171                                     MachineBasicBlock::iterator MBBI,
172                                     DebugLoc DL, bool InProlog) const;
173
174  /// Emit a stub to later inline the target stack probe.
175  MachineInstr *emitStackProbeInlineStub(MachineFunction &MF,
176                                         MachineBasicBlock &MBB,
177                                         MachineBasicBlock::iterator MBBI,
178                                         DebugLoc DL, bool InProlog) const;
179
180  /// Aligns the stack pointer by ANDing it with -MaxAlign.
181  void BuildStackAlignAND(MachineBasicBlock &MBB,
182                          MachineBasicBlock::iterator MBBI, DebugLoc DL,
183                          unsigned Reg, uint64_t MaxAlign) const;
184
185  /// Make small positive stack adjustments using POPs.
186  bool adjustStackWithPops(MachineBasicBlock &MBB,
187                           MachineBasicBlock::iterator MBBI, DebugLoc DL,
188                           int Offset) const;
189
190  /// Adjusts the stack pointer using LEA, SUB, or ADD.
191  MachineInstrBuilder BuildStackAdjustment(MachineBasicBlock &MBB,
192                                           MachineBasicBlock::iterator MBBI,
193                                           DebugLoc DL, int64_t Offset,
194                                           bool InEpilogue) const;
195
196  unsigned getPSPSlotOffsetFromSP(const MachineFunction &MF) const;
197
198  unsigned getWinEHFuncletFrameSize(const MachineFunction &MF) const;
199};
200
201} // End llvm namespace
202
203#endif
204