X86FrameLowering.h
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//===-- X86TargetFrameLowering.h - Define frame lowering for X86 -*- C++ -*-==//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This class implements X86-specific bits of TargetFrameLowering class.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIB_TARGET_X86_X86FRAMELOWERING_H
#define LLVM_LIB_TARGET_X86_X86FRAMELOWERING_H
#include "llvm/CodeGen/TargetFrameLowering.h"
namespace llvm {
class MachineInstrBuilder;
class MCCFIInstruction;
class X86InstrInfo;
class X86Subtarget;
class X86RegisterInfo;
class X86FrameLowering : public TargetFrameLowering {
public:
X86FrameLowering(const X86Subtarget &STI, MaybeAlign StackAlignOverride);
// Cached subtarget predicates.
const X86Subtarget &STI;
const X86InstrInfo &TII;
const X86RegisterInfo *TRI;
unsigned SlotSize;
/// Is64Bit implies that x86_64 instructions are available.
bool Is64Bit;
bool IsLP64;
/// True if the 64-bit frame or stack pointer should be used. True for most
/// 64-bit targets with the exception of x32. If this is false, 32-bit
/// instruction operands should be used to manipulate StackPtr and FramePtr.
bool Uses64BitFramePtr;
unsigned StackPtr;
/// Emit target stack probe code. This is required for all
/// large stack allocations on Windows. The caller is required to materialize
/// the number of bytes to probe in RAX/EAX.
void emitStackProbe(MachineFunction &MF, MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI, const DebugLoc &DL,
bool InProlog) const;
/// Replace a StackProbe inline-stub with the actual probe code inline.
void inlineStackProbe(MachineFunction &MF,
MachineBasicBlock &PrologMBB) const override;
void
emitCalleeSavedFrameMoves(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI) const override;
void emitCalleeSavedFrameMoves(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
const DebugLoc &DL,
bool IsPrologue) const override;
/// emitProlog/emitEpilog - These methods insert prolog and epilog code into
/// the function.
void emitPrologue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
void emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
void adjustForSegmentedStacks(MachineFunction &MF,
MachineBasicBlock &PrologueMBB) const override;
void adjustForHiPEPrologue(MachineFunction &MF,
MachineBasicBlock &PrologueMBB) const override;
void determineCalleeSaves(MachineFunction &MF, BitVector &SavedRegs,
RegScavenger *RS = nullptr) const override;
bool
assignCalleeSavedSpillSlots(MachineFunction &MF,
const TargetRegisterInfo *TRI,
std::vector<CalleeSavedInfo> &CSI) const override;
bool spillCalleeSavedRegisters(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI,
ArrayRef<CalleeSavedInfo> CSI,
const TargetRegisterInfo *TRI) const override;
bool
restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI,
MutableArrayRef<CalleeSavedInfo> CSI,
const TargetRegisterInfo *TRI) const override;
bool hasFP(const MachineFunction &MF) const override;
bool hasReservedCallFrame(const MachineFunction &MF) const override;
bool canSimplifyCallFramePseudos(const MachineFunction &MF) const override;
bool needsFrameIndexResolution(const MachineFunction &MF) const override;
int getFrameIndexReference(const MachineFunction &MF, int FI,
Register &FrameReg) const override;
int getWin64EHFrameIndexRef(const MachineFunction &MF, int FI,
Register &SPReg) const;
int getFrameIndexReferenceSP(const MachineFunction &MF, int FI,
Register &SPReg, int Adjustment) const;
int getFrameIndexReferencePreferSP(const MachineFunction &MF, int FI,
Register &FrameReg,
bool IgnoreSPUpdates) const override;
MachineBasicBlock::iterator
eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI) const override;
unsigned getWinEHParentFrameOffset(const MachineFunction &MF) const override;
void processFunctionBeforeFrameFinalized(MachineFunction &MF,
RegScavenger *RS) const override;
void
processFunctionBeforeFrameIndicesReplaced(MachineFunction &MF,
RegScavenger *RS) const override;
/// Check the instruction before/after the passed instruction. If
/// it is an ADD/SUB/LEA instruction it is deleted argument and the
/// stack adjustment is returned as a positive value for ADD/LEA and
/// a negative for SUB.
int mergeSPUpdates(MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI,
bool doMergeWithPrevious) const;
/// Emit a series of instructions to increment / decrement the stack
/// pointer by a constant value.
void emitSPUpdate(MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI,
const DebugLoc &DL, int64_t NumBytes, bool InEpilogue) const;
/// Check that LEA can be used on SP in an epilogue sequence for \p MF.
bool canUseLEAForSPInEpilogue(const MachineFunction &MF) const;
/// Check whether or not the given \p MBB can be used as a prologue
/// for the target.
/// The prologue will be inserted first in this basic block.
/// This method is used by the shrink-wrapping pass to decide if
/// \p MBB will be correctly handled by the target.
/// As soon as the target enable shrink-wrapping without overriding
/// this method, we assume that each basic block is a valid
/// prologue.
bool canUseAsPrologue(const MachineBasicBlock &MBB) const override;
/// Check whether or not the given \p MBB can be used as a epilogue
/// for the target.
/// The epilogue will be inserted before the first terminator of that block.
/// This method is used by the shrink-wrapping pass to decide if
/// \p MBB will be correctly handled by the target.
bool canUseAsEpilogue(const MachineBasicBlock &MBB) const override;
/// Returns true if the target will correctly handle shrink wrapping.
bool enableShrinkWrapping(const MachineFunction &MF) const override;
/// Order the symbols in the local stack.
/// We want to place the local stack objects in some sort of sensible order.
/// The heuristic we use is to try and pack them according to static number
/// of uses and size in order to minimize code size.
void orderFrameObjects(const MachineFunction &MF,
SmallVectorImpl<int> &ObjectsToAllocate) const override;
/// Wraps up getting a CFI index and building a MachineInstr for it.
void BuildCFI(MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI,
const DebugLoc &DL, const MCCFIInstruction &CFIInst) const;
/// Sets up EBP and optionally ESI based on the incoming EBP value. Only
/// needed for 32-bit. Used in funclet prologues and at catchret destinations.
MachineBasicBlock::iterator
restoreWin32EHStackPointers(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
const DebugLoc &DL, bool RestoreSP = false) const;
void restoreWinEHStackPointersInParent(MachineFunction &MF) const;
int getInitialCFAOffset(const MachineFunction &MF) const override;
Register getInitialCFARegister(const MachineFunction &MF) const override;
/// Return true if the function has a redzone (accessible bytes past the
/// frame of the top of stack function) as part of it's ABI.
bool has128ByteRedZone(const MachineFunction& MF) const;
private:
uint64_t calculateMaxStackAlign(const MachineFunction &MF) const;
/// Emit target stack probe as a call to a helper function
void emitStackProbeCall(MachineFunction &MF, MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI, const DebugLoc &DL,
bool InProlog) const;
/// Emit target stack probe as an inline sequence.
void emitStackProbeInline(MachineFunction &MF, MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
const DebugLoc &DL, bool InProlog) const;
void emitStackProbeInlineWindowsCoreCLR64(MachineFunction &MF,
MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
const DebugLoc &DL,
bool InProlog) const;
void emitStackProbeInlineGeneric(MachineFunction &MF, MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
const DebugLoc &DL, bool InProlog) const;
void emitStackProbeInlineGenericBlock(MachineFunction &MF,
MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
const DebugLoc &DL, uint64_t Offset,
uint64_t Align) const;
void emitStackProbeInlineGenericLoop(MachineFunction &MF,
MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
const DebugLoc &DL, uint64_t Offset,
uint64_t Align) const;
/// Emit a stub to later inline the target stack probe.
MachineInstr *emitStackProbeInlineStub(MachineFunction &MF,
MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
const DebugLoc &DL,
bool InProlog) const;
/// Aligns the stack pointer by ANDing it with -MaxAlign.
void BuildStackAlignAND(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI, const DebugLoc &DL,
unsigned Reg, uint64_t MaxAlign) const;
/// Make small positive stack adjustments using POPs.
bool adjustStackWithPops(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI, const DebugLoc &DL,
int Offset) const;
/// Adjusts the stack pointer using LEA, SUB, or ADD.
MachineInstrBuilder BuildStackAdjustment(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
const DebugLoc &DL, int64_t Offset,
bool InEpilogue) const;
unsigned getPSPSlotOffsetFromSP(const MachineFunction &MF) const;
unsigned getWinEHFuncletFrameSize(const MachineFunction &MF) const;
/// Materialize the catchret target MBB in RAX.
void emitCatchRetReturnValue(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
MachineInstr *CatchRet) const;
};
} // End llvm namespace
#endif