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 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.
53 void emitStackProbe(MachineFunction &MF, MachineBasicBlock &MBB,
54 MachineBasicBlock::iterator MBBI, const DebugLoc &DL,
57 /// Replace a StackProbe inline-stub with the actual probe code inline.
58 void inlineStackProbe(MachineFunction &MF,
59 MachineBasicBlock &PrologMBB) const override;
61 void emitCalleeSavedFrameMoves(MachineBasicBlock &MBB,
62 MachineBasicBlock::iterator MBBI,
63 const DebugLoc &DL) const;
65 /// emitProlog/emitEpilog - These methods insert prolog and epilog code into
67 void emitPrologue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
68 void emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
70 void adjustForSegmentedStacks(MachineFunction &MF,
71 MachineBasicBlock &PrologueMBB) const override;
73 void adjustForHiPEPrologue(MachineFunction &MF,
74 MachineBasicBlock &PrologueMBB) const override;
76 void determineCalleeSaves(MachineFunction &MF, BitVector &SavedRegs,
77 RegScavenger *RS = nullptr) const override;
80 assignCalleeSavedSpillSlots(MachineFunction &MF,
81 const TargetRegisterInfo *TRI,
82 std::vector<CalleeSavedInfo> &CSI) const override;
84 bool spillCalleeSavedRegisters(MachineBasicBlock &MBB,
85 MachineBasicBlock::iterator MI,
86 const std::vector<CalleeSavedInfo> &CSI,
87 const TargetRegisterInfo *TRI) const override;
89 bool restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
90 MachineBasicBlock::iterator MI,
91 const std::vector<CalleeSavedInfo> &CSI,
92 const TargetRegisterInfo *TRI) const override;
94 bool hasFP(const MachineFunction &MF) const override;
95 bool hasReservedCallFrame(const MachineFunction &MF) const override;
96 bool canSimplifyCallFramePseudos(const MachineFunction &MF) const override;
97 bool needsFrameIndexResolution(const MachineFunction &MF) const override;
99 int getFrameIndexReference(const MachineFunction &MF, int FI,
100 unsigned &FrameReg) const override;
102 int getFrameIndexReferencePreferSP(const MachineFunction &MF, int FI,
104 bool IgnoreSPUpdates) const override;
106 MachineBasicBlock::iterator
107 eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
108 MachineBasicBlock::iterator MI) const override;
110 unsigned getWinEHParentFrameOffset(const MachineFunction &MF) const override;
112 void processFunctionBeforeFrameFinalized(MachineFunction &MF,
113 RegScavenger *RS) const override;
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;
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;
127 /// Check that LEA can be used on SP in an epilogue sequence for \p MF.
128 bool canUseLEAForSPInEpilogue(const MachineFunction &MF) const;
130 /// Check whether or not the given \p MBB can be used as a prologue
132 /// The prologue will be inserted first in this basic 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 /// As soon as the target enable shrink-wrapping without overriding
136 /// this method, we assume that each basic block is a valid
138 bool canUseAsPrologue(const MachineBasicBlock &MBB) const override;
140 /// Check whether or not the given \p MBB can be used as a epilogue
142 /// The epilogue will be inserted before the first terminator of that block.
143 /// This method is used by the shrink-wrapping pass to decide if
144 /// \p MBB will be correctly handled by the target.
145 bool canUseAsEpilogue(const MachineBasicBlock &MBB) const override;
147 /// Returns true if the target will correctly handle shrink wrapping.
148 bool enableShrinkWrapping(const MachineFunction &MF) const override;
150 /// Order the symbols in the local stack.
151 /// We want to place the local stack objects in some sort of sensible order.
152 /// The heuristic we use is to try and pack them according to static number
153 /// of uses and size in order to minimize code size.
154 void orderFrameObjects(const MachineFunction &MF,
155 SmallVectorImpl<int> &ObjectsToAllocate) const override;
157 /// convertArgMovsToPushes - This method tries to convert a call sequence
158 /// that uses sub and mov instructions to put the argument onto the stack
159 /// into a series of pushes.
160 /// Returns true if the transformation succeeded, false if not.
161 bool convertArgMovsToPushes(MachineFunction &MF,
162 MachineBasicBlock &MBB,
163 MachineBasicBlock::iterator I,
164 uint64_t Amount) const;
166 /// Wraps up getting a CFI index and building a MachineInstr for it.
167 void BuildCFI(MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI,
168 const DebugLoc &DL, const MCCFIInstruction &CFIInst) const;
170 /// Sets up EBP and optionally ESI based on the incoming EBP value. Only
171 /// needed for 32-bit. Used in funclet prologues and at catchret destinations.
172 MachineBasicBlock::iterator
173 restoreWin32EHStackPointers(MachineBasicBlock &MBB,
174 MachineBasicBlock::iterator MBBI,
175 const DebugLoc &DL, bool RestoreSP = false) const;
178 uint64_t calculateMaxStackAlign(const MachineFunction &MF) const;
180 /// Emit target stack probe as a call to a helper function
181 void emitStackProbeCall(MachineFunction &MF, MachineBasicBlock &MBB,
182 MachineBasicBlock::iterator MBBI, const DebugLoc &DL,
183 bool InProlog) const;
185 /// Emit target stack probe as an inline sequence.
186 void emitStackProbeInline(MachineFunction &MF, MachineBasicBlock &MBB,
187 MachineBasicBlock::iterator MBBI,
188 const DebugLoc &DL, bool InProlog) const;
190 /// Emit a stub to later inline the target stack probe.
191 void emitStackProbeInlineStub(MachineFunction &MF, MachineBasicBlock &MBB,
192 MachineBasicBlock::iterator MBBI,
193 const DebugLoc &DL, bool InProlog) const;
195 /// Aligns the stack pointer by ANDing it with -MaxAlign.
196 void BuildStackAlignAND(MachineBasicBlock &MBB,
197 MachineBasicBlock::iterator MBBI, const DebugLoc &DL,
198 unsigned Reg, uint64_t MaxAlign) const;
200 /// Make small positive stack adjustments using POPs.
201 bool adjustStackWithPops(MachineBasicBlock &MBB,
202 MachineBasicBlock::iterator MBBI, const DebugLoc &DL,
205 /// Adjusts the stack pointer using LEA, SUB, or ADD.
206 MachineInstrBuilder BuildStackAdjustment(MachineBasicBlock &MBB,
207 MachineBasicBlock::iterator MBBI,
208 const DebugLoc &DL, int64_t Offset,
209 bool InEpilogue) const;
211 unsigned getPSPSlotOffsetFromSP(const MachineFunction &MF) const;
213 unsigned getWinEHFuncletFrameSize(const MachineFunction &MF) const;
216 } // End llvm namespace