1 //===-- X86TargetFrameLowering.h - Define frame lowering for X86 -*- C++ -*-==//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This class implements X86-specific bits of TargetFrameLowering class.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_LIB_TARGET_X86_X86FRAMELOWERING_H
15 #define LLVM_LIB_TARGET_X86_X86FRAMELOWERING_H
17 #include "llvm/Target/TargetFrameLowering.h"
21 class MachineInstrBuilder;
22 class MCCFIInstruction;
24 class X86RegisterInfo;
26 class X86FrameLowering : public TargetFrameLowering {
28 X86FrameLowering(const X86Subtarget &STI, unsigned StackAlignOverride);
30 // Cached subtarget predicates.
32 const X86Subtarget &STI;
33 const TargetInstrInfo &TII;
34 const X86RegisterInfo *TRI;
38 /// Is64Bit implies that x86_64 instructions are available.
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;
50 /// Emit a call to the target's stack probe function. 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.
53 void emitStackProbeCall(MachineFunction &MF, MachineBasicBlock &MBB,
54 MachineBasicBlock::iterator MBBI, DebugLoc DL) const;
56 void emitCalleeSavedFrameMoves(MachineBasicBlock &MBB,
57 MachineBasicBlock::iterator MBBI,
60 /// emitProlog/emitEpilog - These methods insert prolog and epilog code into
62 void emitPrologue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
63 void emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
65 void adjustForSegmentedStacks(MachineFunction &MF,
66 MachineBasicBlock &PrologueMBB) const override;
68 void adjustForHiPEPrologue(MachineFunction &MF,
69 MachineBasicBlock &PrologueMBB) const override;
71 void processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
72 RegScavenger *RS = nullptr) const override;
75 assignCalleeSavedSpillSlots(MachineFunction &MF,
76 const TargetRegisterInfo *TRI,
77 std::vector<CalleeSavedInfo> &CSI) const override;
79 bool spillCalleeSavedRegisters(MachineBasicBlock &MBB,
80 MachineBasicBlock::iterator MI,
81 const std::vector<CalleeSavedInfo> &CSI,
82 const TargetRegisterInfo *TRI) const override;
84 bool restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
85 MachineBasicBlock::iterator MI,
86 const std::vector<CalleeSavedInfo> &CSI,
87 const TargetRegisterInfo *TRI) const override;
89 bool hasFP(const MachineFunction &MF) const override;
90 bool hasReservedCallFrame(const MachineFunction &MF) const override;
91 bool canSimplifyCallFramePseudos(const MachineFunction &MF) const override;
92 bool needsFrameIndexResolution(const MachineFunction &MF) const override;
94 int getFrameIndexOffset(const MachineFunction &MF, int FI) const override;
95 int getFrameIndexReference(const MachineFunction &MF, int FI,
96 unsigned &FrameReg) const override;
98 int getFrameIndexOffsetFromSP(const MachineFunction &MF, int FI) const;
99 int getFrameIndexReferenceFromSP(const MachineFunction &MF, int FI,
100 unsigned &FrameReg) const override;
102 void eliminateCallFramePseudoInstr(MachineFunction &MF,
103 MachineBasicBlock &MBB,
104 MachineBasicBlock::iterator MI) const override;
106 /// Check the instruction before/after the passed instruction. If
107 /// it is an ADD/SUB/LEA instruction it is deleted argument and the
108 /// stack adjustment is returned as a positive value for ADD/LEA and
109 /// a negative for SUB.
110 int mergeSPUpdates(MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI,
111 bool doMergeWithPrevious) const;
113 /// Emit a series of instructions to increment / decrement the stack
114 /// pointer by a constant value.
115 void emitSPUpdate(MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI,
116 int64_t NumBytes, bool InEpilogue) const;
118 /// Check that LEA can be used on SP in an epilogue sequence for \p MF.
119 bool canUseLEAForSPInEpilogue(const MachineFunction &MF) const;
121 /// Check whether or not the given \p MBB can be used as a epilogue
123 /// The epilogue will be inserted before the first terminator of that block.
124 /// This method is used by the shrink-wrapping pass to decide if
125 /// \p MBB will be correctly handled by the target.
126 bool canUseAsEpilogue(const MachineBasicBlock &MBB) const override;
129 /// convertArgMovsToPushes - This method tries to convert a call sequence
130 /// that uses sub and mov instructions to put the argument onto the stack
131 /// into a series of pushes.
132 /// Returns true if the transformation succeeded, false if not.
133 bool convertArgMovsToPushes(MachineFunction &MF,
134 MachineBasicBlock &MBB,
135 MachineBasicBlock::iterator I,
136 uint64_t Amount) const;
138 uint64_t calculateMaxStackAlign(const MachineFunction &MF) const;
140 /// Wraps up getting a CFI index and building a MachineInstr for it.
141 void BuildCFI(MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI,
142 DebugLoc DL, MCCFIInstruction CFIInst) const;
144 /// Aligns the stack pointer by ANDing it with -MaxAlign.
145 void BuildStackAlignAND(MachineBasicBlock &MBB,
146 MachineBasicBlock::iterator MBBI, DebugLoc DL,
147 uint64_t MaxAlign) const;
149 /// Adjusts the stack pointer using LEA, SUB, or ADD.
150 MachineInstrBuilder BuildStackAdjustment(MachineBasicBlock &MBB,
151 MachineBasicBlock::iterator MBBI,
152 DebugLoc DL, int64_t Offset,
153 bool InEpilogue) const;
156 } // End llvm namespace