llvm-6502/lib/Target/X86/X86RegisterInfo.h
JF Bastien 9994b911f4 Targets: commonize some stack realignment code
This patch does the following:
* Fix FIXME on `needsStackRealignment`: it is now shared between multiple targets, implemented in `TargetRegisterInfo`, and isn't `virtual` anymore. This will break out-of-tree targets, silently if they used `virtual` and with a build error if they used `override`.
* Factor out `canRealignStack` as a `virtual` function on `TargetRegisterInfo`, by default only looks for the `no-realign-stack` function attribute.

Multiple targets duplicated the same `needsStackRealignment` code:
 - Aarch64.
 - ARM.
 - Mips almost: had extra `DEBUG` diagnostic, which the default implementation now has.
 - PowerPC.
 - WebAssembly.
 - x86 almost: has an extra `-force-align-stack` option, which the default implementation now has.

The default implementation of `needsStackRealignment` used to just return `false`. My current patch changes the behavior by simply using the above shared behavior. This affects:
 - AMDGPU
 - BPF
 - CppBackend
 - MSP430
 - NVPTX
 - Sparc
 - SystemZ
 - XCore
 - Out-of-tree targets
This is a breaking change! `make check` passes.

The only implementation of the `virtual` function (besides the slight different in x86) was Hexagon (which did `MF.getFrameInfo()->getMaxAlignment() > 8`), and potentially some out-of-tree targets. Hexagon now uses the default implementation.

`needsStackRealignment` was being overwritten in `<Target>GenRegisterInfo.inc`, to return `false` as the default also did. That was odd and is now gone.

Reviewers: sunfish

Subscribers: aemerson, llvm-commits, jfb

Differential Revision: http://reviews.llvm.org/D11160

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@242727 91177308-0d34-0410-b5e6-96231b3b80d8
2015-07-20 22:51:32 +00:00

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5.2 KiB
C++

//===-- X86RegisterInfo.h - X86 Register Information Impl -------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains the X86 implementation of the TargetRegisterInfo class.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIB_TARGET_X86_X86REGISTERINFO_H
#define LLVM_LIB_TARGET_X86_X86REGISTERINFO_H
#include "llvm/Target/TargetRegisterInfo.h"
#define GET_REGINFO_HEADER
#include "X86GenRegisterInfo.inc"
namespace llvm {
class Triple;
class X86RegisterInfo final : public X86GenRegisterInfo {
private:
/// Is64Bit - Is the target 64-bits.
///
bool Is64Bit;
/// IsWin64 - Is the target on of win64 flavours
///
bool IsWin64;
/// SlotSize - Stack slot size in bytes.
///
unsigned SlotSize;
/// StackPtr - X86 physical register used as stack ptr.
///
unsigned StackPtr;
/// FramePtr - X86 physical register used as frame ptr.
///
unsigned FramePtr;
/// BasePtr - X86 physical register used as a base ptr in complex stack
/// frames. I.e., when we need a 3rd base, not just SP and FP, due to
/// variable size stack objects.
unsigned BasePtr;
public:
X86RegisterInfo(const Triple &TT);
// FIXME: This should be tablegen'd like getDwarfRegNum is
int getSEHRegNum(unsigned i) const;
/// Code Generation virtual methods...
///
bool trackLivenessAfterRegAlloc(const MachineFunction &MF) const override;
/// getMatchingSuperRegClass - Return a subclass of the specified register
/// class A so that each register in it has a sub-register of the
/// specified sub-register index which is in the specified register class B.
const TargetRegisterClass *
getMatchingSuperRegClass(const TargetRegisterClass *A,
const TargetRegisterClass *B,
unsigned Idx) const override;
const TargetRegisterClass *
getSubClassWithSubReg(const TargetRegisterClass *RC,
unsigned Idx) const override;
const TargetRegisterClass *
getLargestLegalSuperClass(const TargetRegisterClass *RC,
const MachineFunction &MF) const override;
/// getPointerRegClass - Returns a TargetRegisterClass used for pointer
/// values.
const TargetRegisterClass *
getPointerRegClass(const MachineFunction &MF,
unsigned Kind = 0) const override;
/// getCrossCopyRegClass - Returns a legal register class to copy a register
/// in the specified class to or from. Returns NULL if it is possible to copy
/// between a two registers of the specified class.
const TargetRegisterClass *
getCrossCopyRegClass(const TargetRegisterClass *RC) const override;
unsigned getRegPressureLimit(const TargetRegisterClass *RC,
MachineFunction &MF) const override;
/// getCalleeSavedRegs - Return a null-terminated list of all of the
/// callee-save registers on this target.
const MCPhysReg *
getCalleeSavedRegs(const MachineFunction* MF) const override;
const uint32_t *getCallPreservedMask(const MachineFunction &MF,
CallingConv::ID) const override;
const uint32_t *getNoPreservedMask() const;
/// getReservedRegs - Returns a bitset indexed by physical register number
/// indicating if a register is a special register that has particular uses and
/// should be considered unavailable at all times, e.g. SP, RA. This is used by
/// register scavenger to determine what registers are free.
BitVector getReservedRegs(const MachineFunction &MF) const override;
void adjustStackMapLiveOutMask(uint32_t *Mask) const override;
bool hasBasePointer(const MachineFunction &MF) const;
bool canRealignStack(const MachineFunction &MF) const override;
bool hasReservedSpillSlot(const MachineFunction &MF, unsigned Reg,
int &FrameIdx) const override;
void eliminateFrameIndex(MachineBasicBlock::iterator MI,
int SPAdj, unsigned FIOperandNum,
RegScavenger *RS = nullptr) const override;
// Debug information queries.
unsigned getFrameRegister(const MachineFunction &MF) const override;
unsigned getPtrSizedFrameRegister(const MachineFunction &MF) const;
unsigned getStackRegister() const { return StackPtr; }
unsigned getBaseRegister() const { return BasePtr; }
// FIXME: Move to FrameInfok
unsigned getSlotSize() const { return SlotSize; }
};
/// Returns the sub or super register of a specific X86 register.
/// e.g. getX86SubSuperRegister(X86::EAX, MVT::i16) returns X86::AX.
/// Aborts on error.
unsigned getX86SubSuperRegister(unsigned, MVT::SimpleValueType, bool High=false);
/// Returns the sub or super register of a specific X86 register.
/// Like getX86SubSuperRegister() but returns 0 on error.
unsigned getX86SubSuperRegisterOrZero(unsigned, MVT::SimpleValueType,
bool High = false);
//get512BitRegister - X86 utility - returns 512-bit super register
unsigned get512BitSuperRegister(unsigned Reg);
} // End llvm namespace
#endif