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llvm-mirror/lib/Target/X86/X86FrameLowering.h
Reid Kleckner fc2be394ef [WinEH] Emit prologues and epilogues for funclets
Summary:
32-bit funclets have short prologues that allocate enough stack for the
largest call in the whole function. The runtime saves CSRs for the
funclet. It doesn't restore CSRs after we finally transfer control back
to the parent funciton via a CATCHRET, but that's a separate issue.
32-bit funclets also have to adjust the incoming EBP value, which is
what llvm.x86.seh.recoverframe does in the old model.

64-bit funclets need to spill CSRs as normal. For simplicity, this just
spills the same set of CSRs as the parent function, rather than trying
to compute different CSR sets for the parent function and each funclet.
64-bit funclets also allocate enough stack space for the largest
outgoing call frame, like 32-bit.

Reviewers: majnemer

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D12546

llvm-svn: 247092
2015-09-08 22:44:41 +00:00

169 lines
7.0 KiB
C++

//===-- X86TargetFrameLowering.h - Define frame lowering for X86 -*- C++ -*-==//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// 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/Target/TargetFrameLowering.h"
namespace llvm {
class MachineInstrBuilder;
class MCCFIInstruction;
class X86Subtarget;
class X86RegisterInfo;
class X86FrameLowering : public TargetFrameLowering {
public:
X86FrameLowering(const X86Subtarget &STI, unsigned StackAlignOverride);
// Cached subtarget predicates.
const X86Subtarget &STI;
const TargetInstrInfo &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 a call to the target's stack probe function. 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 emitStackProbeCall(MachineFunction &MF, MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI, DebugLoc DL) const;
void emitCalleeSavedFrameMoves(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
DebugLoc DL) const;
/// 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,
const std::vector<CalleeSavedInfo> &CSI,
const TargetRegisterInfo *TRI) const override;
bool restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI,
const std::vector<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,
unsigned &FrameReg) const override;
int getFrameIndexReferenceFromSP(const MachineFunction &MF, int FI,
unsigned &FrameReg) const override;
void eliminateCallFramePseudoInstr(MachineFunction &MF,
MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI) 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,
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 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;
private:
/// convertArgMovsToPushes - This method tries to convert a call sequence
/// that uses sub and mov instructions to put the argument onto the stack
/// into a series of pushes.
/// Returns true if the transformation succeeded, false if not.
bool convertArgMovsToPushes(MachineFunction &MF,
MachineBasicBlock &MBB,
MachineBasicBlock::iterator I,
uint64_t Amount) const;
uint64_t calculateMaxStackAlign(const MachineFunction &MF) const;
/// Wraps up getting a CFI index and building a MachineInstr for it.
void BuildCFI(MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI,
DebugLoc DL, MCCFIInstruction CFIInst) const;
/// Aligns the stack pointer by ANDing it with -MaxAlign.
void BuildStackAlignAND(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI, DebugLoc DL,
uint64_t MaxAlign) const;
/// Make small positive stack adjustments using POPs.
bool adjustStackWithPops(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI, DebugLoc DL,
int Offset) const;
/// Adjusts the stack pointer using LEA, SUB, or ADD.
MachineInstrBuilder BuildStackAdjustment(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
DebugLoc DL, int64_t Offset,
bool InEpilogue) 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
restoreWin32EHFrameAndBasePtr(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
DebugLoc DL) const;
};
} // End llvm namespace
#endif