LLVM  14.0.0git
X86FrameLowering.h
Go to the documentation of this file.
1 //===-- X86TargetFrameLowering.h - Define frame lowering for X86 -*- C++ -*-==//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This class implements X86-specific bits of TargetFrameLowering class.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef LLVM_LIB_TARGET_X86_X86FRAMELOWERING_H
14 #define LLVM_LIB_TARGET_X86_X86FRAMELOWERING_H
15 
17 #include "llvm/Support/TypeSize.h"
18 
19 namespace llvm {
20 
21 class MachineInstrBuilder;
22 class MCCFIInstruction;
23 class X86InstrInfo;
24 class X86Subtarget;
25 class X86RegisterInfo;
26 
28 public:
29  X86FrameLowering(const X86Subtarget &STI, MaybeAlign StackAlignOverride);
30 
31  // Cached subtarget predicates.
32 
33  const X86Subtarget &STI;
34  const X86InstrInfo &TII;
36 
37  unsigned SlotSize;
38 
39  /// Is64Bit implies that x86_64 instructions are available.
40  bool Is64Bit;
41 
42  bool IsLP64;
43 
44  /// True if the 64-bit frame or stack pointer should be used. True for most
45  /// 64-bit targets with the exception of x32. If this is false, 32-bit
46  /// instruction operands should be used to manipulate StackPtr and FramePtr.
48 
49  unsigned StackPtr;
50 
51  /// Emit target stack probe code. This is required for all
52  /// large stack allocations on Windows. The caller is required to materialize
53  /// the number of bytes to probe in RAX/EAX.
56  bool InProlog) const;
57 
58  /// Replace a StackProbe inline-stub with the actual probe code inline.
60  MachineBasicBlock &PrologMBB) const override;
61 
62  void
64  MachineBasicBlock::iterator MBBI) const override;
65 
68  const DebugLoc &DL, bool IsPrologue) const;
69 
70  /// emitProlog/emitEpilog - These methods insert prolog and epilog code into
71  /// the function.
72  void emitPrologue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
73  void emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
74 
76  MachineBasicBlock &PrologueMBB) const override;
77 
79  MachineBasicBlock &PrologueMBB) const override;
80 
81  void determineCalleeSaves(MachineFunction &MF, BitVector &SavedRegs,
82  RegScavenger *RS = nullptr) const override;
83 
84  bool
86  const TargetRegisterInfo *TRI,
87  std::vector<CalleeSavedInfo> &CSI) const override;
88 
92  const TargetRegisterInfo *TRI) const override;
93 
94  bool
98  const TargetRegisterInfo *TRI) const override;
99 
100  bool hasFP(const MachineFunction &MF) const override;
101  bool hasReservedCallFrame(const MachineFunction &MF) const override;
102  bool canSimplifyCallFramePseudos(const MachineFunction &MF) const override;
103  bool needsFrameIndexResolution(const MachineFunction &MF) const override;
104 
106  Register &FrameReg) const override;
107 
108  int getWin64EHFrameIndexRef(const MachineFunction &MF, int FI,
109  Register &SPReg) const;
111  Register &SPReg, int Adjustment) const;
114  Register &FrameReg,
115  bool IgnoreSPUpdates) const override;
116 
119  MachineBasicBlock::iterator MI) const override;
120 
121  unsigned getWinEHParentFrameOffset(const MachineFunction &MF) const override;
122 
124  RegScavenger *RS) const override;
125 
126  void
128  RegScavenger *RS) const override;
129 
130  /// Check the instruction before/after the passed instruction. If
131  /// it is an ADD/SUB/LEA instruction it is deleted argument and the
132  /// stack adjustment is returned as a positive value for ADD/LEA and
133  /// a negative for SUB.
135  bool doMergeWithPrevious) const;
136 
137  /// Emit a series of instructions to increment / decrement the stack
138  /// pointer by a constant value.
140  const DebugLoc &DL, int64_t NumBytes, bool InEpilogue) const;
141 
142  /// Check that LEA can be used on SP in an epilogue sequence for \p MF.
143  bool canUseLEAForSPInEpilogue(const MachineFunction &MF) const;
144 
145  /// Check whether or not the given \p MBB can be used as a prologue
146  /// for the target.
147  /// The prologue will be inserted first in this basic block.
148  /// This method is used by the shrink-wrapping pass to decide if
149  /// \p MBB will be correctly handled by the target.
150  /// As soon as the target enable shrink-wrapping without overriding
151  /// this method, we assume that each basic block is a valid
152  /// prologue.
153  bool canUseAsPrologue(const MachineBasicBlock &MBB) const override;
154 
155  /// Check whether or not the given \p MBB can be used as a epilogue
156  /// for the target.
157  /// The epilogue will be inserted before the first terminator of that block.
158  /// This method is used by the shrink-wrapping pass to decide if
159  /// \p MBB will be correctly handled by the target.
160  bool canUseAsEpilogue(const MachineBasicBlock &MBB) const override;
161 
162  /// Returns true if the target will correctly handle shrink wrapping.
163  bool enableShrinkWrapping(const MachineFunction &MF) const override;
164 
165  /// Order the symbols in the local stack.
166  /// We want to place the local stack objects in some sort of sensible order.
167  /// The heuristic we use is to try and pack them according to static number
168  /// of uses and size in order to minimize code size.
169  void orderFrameObjects(const MachineFunction &MF,
170  SmallVectorImpl<int> &ObjectsToAllocate) const override;
171 
172  /// Wraps up getting a CFI index and building a MachineInstr for it.
174  const DebugLoc &DL, const MCCFIInstruction &CFIInst) const;
175 
176  /// Sets up EBP and optionally ESI based on the incoming EBP value. Only
177  /// needed for 32-bit. Used in funclet prologues and at catchret destinations.
181  const DebugLoc &DL, bool RestoreSP = false) const;
182 
184 
185  int getInitialCFAOffset(const MachineFunction &MF) const override;
186 
187  Register getInitialCFARegister(const MachineFunction &MF) const override;
188 
189  /// Return true if the function has a redzone (accessible bytes past the
190  /// frame of the top of stack function) as part of it's ABI.
191  bool has128ByteRedZone(const MachineFunction& MF) const;
192 
193 private:
194  bool isWin64Prologue(const MachineFunction &MF) const;
195 
196  bool needsDwarfCFI(const MachineFunction &MF) const;
197 
198  uint64_t calculateMaxStackAlign(const MachineFunction &MF) const;
199 
200  /// Emit target stack probe as a call to a helper function
201  void emitStackProbeCall(MachineFunction &MF, MachineBasicBlock &MBB,
203  bool InProlog) const;
204 
205  /// Emit target stack probe as an inline sequence.
206  void emitStackProbeInline(MachineFunction &MF, MachineBasicBlock &MBB,
208  const DebugLoc &DL, bool InProlog) const;
209  void emitStackProbeInlineWindowsCoreCLR64(MachineFunction &MF,
212  const DebugLoc &DL,
213  bool InProlog) const;
214  void emitStackProbeInlineGeneric(MachineFunction &MF, MachineBasicBlock &MBB,
216  const DebugLoc &DL, bool InProlog) const;
217 
218  void emitStackProbeInlineGenericBlock(MachineFunction &MF,
221  const DebugLoc &DL, uint64_t Offset,
222  uint64_t Align) const;
223 
224  void emitStackProbeInlineGenericLoop(MachineFunction &MF,
227  const DebugLoc &DL, uint64_t Offset,
228  uint64_t Align) const;
229 
230  void adjustFrameForMsvcCxxEh(MachineFunction &MF) const;
231 
232  /// Aligns the stack pointer by ANDing it with -MaxAlign.
233  void BuildStackAlignAND(MachineBasicBlock &MBB,
235  unsigned Reg, uint64_t MaxAlign) const;
236 
237  /// Make small positive stack adjustments using POPs.
238  bool adjustStackWithPops(MachineBasicBlock &MBB,
240  int Offset) const;
241 
242  /// Adjusts the stack pointer using LEA, SUB, or ADD.
243  MachineInstrBuilder BuildStackAdjustment(MachineBasicBlock &MBB,
245  const DebugLoc &DL, int64_t Offset,
246  bool InEpilogue) const;
247 
248  unsigned getPSPSlotOffsetFromSP(const MachineFunction &MF) const;
249 
250  unsigned getWinEHFuncletFrameSize(const MachineFunction &MF) const;
251 
252  /// Materialize the catchret target MBB in RAX.
253  void emitCatchRetReturnValue(MachineBasicBlock &MBB,
255  MachineInstr *CatchRet) const;
256 };
257 
258 } // End llvm namespace
259 
260 #endif
llvm::X86FrameLowering::hasReservedCallFrame
bool hasReservedCallFrame(const MachineFunction &MF) const override
hasReservedCallFrame - Under normal circumstances, when a frame pointer is not required,...
Definition: X86FrameLowering.cpp:59
llvm::X86FrameLowering::canUseAsEpilogue
bool canUseAsEpilogue(const MachineBasicBlock &MBB) const override
Check whether or not the given MBB can be used as a epilogue for the target.
Definition: X86FrameLowering.cpp:3368
llvm::X86FrameLowering::TRI
const X86RegisterInfo * TRI
Definition: X86FrameLowering.h:35
llvm::X86FrameLowering::adjustForHiPEPrologue
void adjustForHiPEPrologue(MachineFunction &MF, MachineBasicBlock &PrologueMBB) const override
Erlang programs may need a special prologue to handle the stack size they might need at runtime.
Definition: X86FrameLowering.cpp:3039
MI
IRTranslator LLVM IR MI
Definition: IRTranslator.cpp:103
llvm
---------------------— PointerInfo ------------------------------------—
Definition: AllocatorList.h:23
Reg
unsigned Reg
Definition: MachineSink.cpp:1566
llvm::X86FrameLowering::spillCalleeSavedRegisters
bool spillCalleeSavedRegisters(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI, ArrayRef< CalleeSavedInfo > CSI, const TargetRegisterInfo *TRI) const override
spillCalleeSavedRegisters - Issues instruction(s) to spill all callee saved registers and returns tru...
Definition: X86FrameLowering.cpp:2524
TargetFrameLowering.h
llvm::TargetFrameLowering
Information about stack frame layout on the target.
Definition: TargetFrameLowering.h:43
llvm::X86FrameLowering::hasFP
bool hasFP(const MachineFunction &MF) const override
hasFP - Return true if the specified function should have a dedicated frame pointer register.
Definition: X86FrameLowering.cpp:93
TypeSize.h
llvm::X86Subtarget
Definition: X86Subtarget.h:52
llvm::X86FrameLowering::assignCalleeSavedSpillSlots
bool assignCalleeSavedSpillSlots(MachineFunction &MF, const TargetRegisterInfo *TRI, std::vector< CalleeSavedInfo > &CSI) const override
Definition: X86FrameLowering.cpp:2411
llvm::X86FrameLowering::enableShrinkWrapping
bool enableShrinkWrapping(const MachineFunction &MF) const override
Returns true if the target will correctly handle shrink wrapping.
Definition: X86FrameLowering.cpp:3394
llvm::TargetRegisterInfo
TargetRegisterInfo base class - We assume that the target defines a static array of TargetRegisterDes...
Definition: TargetRegisterInfo.h:233
llvm::X86FrameLowering::orderFrameObjects
void orderFrameObjects(const MachineFunction &MF, SmallVectorImpl< int > &ObjectsToAllocate) const override
Order the symbols in the local stack.
Definition: X86FrameLowering.cpp:3554
llvm::X86FrameLowering::eliminateCallFramePseudoInstr
MachineBasicBlock::iterator eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB, MachineBasicBlock::iterator MI) const override
This method is called during prolog/epilog code insertion to eliminate call frame setup and destroy p...
Definition: X86FrameLowering.cpp:3249
Offset
uint64_t Offset
Definition: ELFObjHandler.cpp:81
llvm::X86FrameLowering::canUseAsPrologue
bool canUseAsPrologue(const MachineBasicBlock &MBB) const override
Check whether or not the given MBB can be used as a prologue for the target.
Definition: X86FrameLowering.cpp:3358
llvm::X86FrameLowering::has128ByteRedZone
bool has128ByteRedZone(const MachineFunction &MF) const
Return true if the function has a redzone (accessible bytes past the frame of the top of stack functi...
Definition: X86FrameLowering.cpp:1216
llvm::X86FrameLowering::getFrameIndexReferencePreferSP
StackOffset getFrameIndexReferencePreferSP(const MachineFunction &MF, int FI, Register &FrameReg, bool IgnoreSPUpdates) const override
Same as getFrameIndexReference, except that the stack pointer (as opposed to the frame pointer) will ...
Definition: X86FrameLowering.cpp:2329
llvm::X86FrameLowering::restoreWinEHStackPointersInParent
void restoreWinEHStackPointersInParent(MachineFunction &MF) const
Definition: X86FrameLowering.cpp:3709
llvm::X86FrameLowering::getWin64EHFrameIndexRef
int getWin64EHFrameIndexRef(const MachineFunction &MF, int FI, Register &SPReg) const
Definition: X86FrameLowering.cpp:2303
llvm::MutableArrayRef
MutableArrayRef - Represent a mutable reference to an array (0 or more elements consecutively in memo...
Definition: ArrayRef.h:307
llvm::X86FrameLowering::needsFrameIndexResolution
bool needsFrameIndexResolution(const MachineFunction &MF) const override
Definition: X86FrameLowering.cpp:85
llvm::X86FrameLowering::getFrameIndexReferenceSP
StackOffset getFrameIndexReferenceSP(const MachineFunction &MF, int FI, Register &SPReg, int Adjustment) const
Definition: X86FrameLowering.cpp:2319
llvm::X86FrameLowering::BuildCFI
void BuildCFI(MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI, const DebugLoc &DL, const MCCFIInstruction &CFIInst) const
Wraps up getting a CFI index and building a MachineInstr for it.
Definition: X86FrameLowering.cpp:425
llvm::X86FrameLowering::canUseLEAForSPInEpilogue
bool canUseLEAForSPInEpilogue(const MachineFunction &MF) const
Check that LEA can be used on SP in an epilogue sequence for MF.
Definition: X86FrameLowering.cpp:1922
llvm::X86FrameLowering::TII
const X86InstrInfo & TII
Definition: X86FrameLowering.h:34
llvm::MaybeAlign
This struct is a compact representation of a valid (power of two) or undefined (0) alignment.
Definition: Alignment.h:109
llvm::X86FrameLowering::processFunctionBeforeFrameIndicesReplaced
void processFunctionBeforeFrameIndicesReplaced(MachineFunction &MF, RegScavenger *RS) const override
processFunctionBeforeFrameIndicesReplaced - This method is called immediately before MO_FrameIndex op...
Definition: X86FrameLowering.cpp:3703
llvm::X86FrameLowering::restoreWin32EHStackPointers
MachineBasicBlock::iterator restoreWin32EHStackPointers(MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI, const DebugLoc &DL, bool RestoreSP=false) const
Sets up EBP and optionally ESI based on the incoming EBP value.
Definition: X86FrameLowering.cpp:3411
llvm::BitVector
Definition: BitVector.h:74
llvm::Align
This struct is a compact representation of a valid (non-zero power of two) alignment.
Definition: Alignment.h:39
llvm::X86FrameLowering::processFunctionBeforeFrameFinalized
void processFunctionBeforeFrameFinalized(MachineFunction &MF, RegScavenger *RS) const override
processFunctionBeforeFrameFinalized - This method is called immediately before the specified function...
Definition: X86FrameLowering.cpp:3638
llvm::MCCFIInstruction
Definition: MCDwarf.h:434
llvm::MachineBasicBlock
Definition: MachineBasicBlock.h:95
llvm::X86FrameLowering::emitSPUpdate
void emitSPUpdate(MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI, const DebugLoc &DL, int64_t NumBytes, bool InEpilogue) const
Emit a series of instructions to increment / decrement the stack pointer by a constant value.
Definition: X86FrameLowering.cpp:205
llvm::MachineInstr
Representation of each machine instruction.
Definition: MachineInstr.h:64
llvm::MachineInstrBuilder
Definition: MachineInstrBuilder.h:69
uint64_t
llvm::X86FrameLowering
Definition: X86FrameLowering.h:27
llvm::X86FrameLowering::emitPrologue
void emitPrologue(MachineFunction &MF, MachineBasicBlock &MBB) const override
emitProlog/emitEpilog - These methods insert prolog and epilog code into the function.
Definition: X86FrameLowering.cpp:1319
llvm::X86FrameLowering::restoreCalleeSavedRegisters
bool restoreCalleeSavedRegisters(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI, MutableArrayRef< CalleeSavedInfo > CSI, const TargetRegisterInfo *TRI) const override
restoreCalleeSavedRegisters - Issues instruction(s) to restore all callee saved registers and returns...
Definition: X86FrameLowering.cpp:2625
llvm::RegScavenger
Definition: RegisterScavenging.h:34
llvm::X86FrameLowering::emitEpilogue
void emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const override
Definition: X86FrameLowering.cpp:2006
llvm::X86FrameLowering::mergeSPUpdates
int mergeSPUpdates(MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI, bool doMergeWithPrevious) const
Check the instruction before/after the passed instruction.
Definition: X86FrameLowering.cpp:363
llvm::MachineFunction
Definition: MachineFunction.h:230
llvm::X86InstrInfo
Definition: X86InstrInfo.h:130
llvm::ArrayRef
ArrayRef - Represent a constant reference to an array (0 or more elements consecutively in memory),...
Definition: APInt.h:32
MBBI
MachineBasicBlock MachineBasicBlock::iterator MBBI
Definition: AArch64SLSHardening.cpp:75
llvm::StackOffset
StackOffset is a class to represent an offset with 2 dimensions, named fixed and scalable,...
Definition: TypeSize.h:134
DL
MachineBasicBlock MachineBasicBlock::iterator DebugLoc DL
Definition: AArch64SLSHardening.cpp:76
llvm::X86FrameLowering::emitStackProbe
void emitStackProbe(MachineFunction &MF, MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI, const DebugLoc &DL, bool InProlog) const
Emit target stack probe code.
Definition: X86FrameLowering.cpp:487
llvm::X86FrameLowering::adjustForSegmentedStacks
void adjustForSegmentedStacks(MachineFunction &MF, MachineBasicBlock &PrologueMBB) const override
Adjust the prologue to have the function use segmented stacks.
Definition: X86FrameLowering.cpp:2746
llvm::Register
Wrapper class representing virtual and physical registers.
Definition: Register.h:19
MBB
MachineBasicBlock & MBB
Definition: AArch64SLSHardening.cpp:74
llvm::X86FrameLowering::SlotSize
unsigned SlotSize
Definition: X86FrameLowering.h:37
llvm::X86FrameLowering::STI
const X86Subtarget & STI
Definition: X86FrameLowering.h:33
llvm::X86FrameLowering::inlineStackProbe
void inlineStackProbe(MachineFunction &MF, MachineBasicBlock &PrologMBB) const override
Replace a StackProbe inline-stub with the actual probe code inline.
Definition: X86FrameLowering.cpp:504
llvm::X86FrameLowering::determineCalleeSaves
void determineCalleeSaves(MachineFunction &MF, BitVector &SavedRegs, RegScavenger *RS=nullptr) const override
This method determines which of the registers reported by TargetRegisterInfo::getCalleeSavedRegs() sh...
Definition: X86FrameLowering.cpp:2679
llvm::X86FrameLowering::IsLP64
bool IsLP64
Definition: X86FrameLowering.h:42
llvm::X86FrameLowering::X86FrameLowering
X86FrameLowering(const X86Subtarget &STI, MaybeAlign StackAlignOverride)
Definition: X86FrameLowering.cpp:45
llvm::X86FrameLowering::canSimplifyCallFramePseudos
bool canSimplifyCallFramePseudos(const MachineFunction &MF) const override
canSimplifyCallFramePseudos - If there is a reserved call frame, the call frame pseudos can be simpli...
Definition: X86FrameLowering.cpp:70
llvm::X86FrameLowering::Is64Bit
bool Is64Bit
Is64Bit implies that x86_64 instructions are available.
Definition: X86FrameLowering.h:40
llvm::X86FrameLowering::Uses64BitFramePtr
bool Uses64BitFramePtr
True if the 64-bit frame or stack pointer should be used.
Definition: X86FrameLowering.h:47
llvm::SmallVectorImpl< int >
llvm::DebugLoc
A debug info location.
Definition: DebugLoc.h:33
llvm::X86FrameLowering::StackPtr
unsigned StackPtr
Definition: X86FrameLowering.h:49
llvm::X86FrameLowering::getWinEHParentFrameOffset
unsigned getWinEHParentFrameOffset(const MachineFunction &MF) const override
Definition: X86FrameLowering.cpp:3626
llvm::MachineInstrBundleIterator< MachineInstr >
llvm::X86FrameLowering::getFrameIndexReference
StackOffset getFrameIndexReference(const MachineFunction &MF, int FI, Register &FrameReg) const override
getFrameIndexReference - This method should return the base register and offset used to reference a f...
Definition: X86FrameLowering.cpp:2221
llvm::X86FrameLowering::getInitialCFAOffset
int getInitialCFAOffset(const MachineFunction &MF) const override
Return initial CFA offset value i.e.
Definition: X86FrameLowering.cpp:3474
llvm::X86FrameLowering::emitCalleeSavedFrameMoves
void emitCalleeSavedFrameMoves(MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI) const override
Emits Dwarf Info specifying offsets of callee saved registers and frame pointer.
Definition: X86FrameLowering.cpp:437
llvm::X86FrameLowering::getInitialCFARegister
Register getInitialCFARegister(const MachineFunction &MF) const override
Return initial CFA register value i.e.
Definition: X86FrameLowering.cpp:3479
llvm::X86RegisterInfo
Definition: X86RegisterInfo.h:24