llvm-6502/lib/Target/WebAssembly/WebAssemblyRegisterInfo.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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// WebAssemblyRegisterInfo.h - WebAssembly 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.
//
//===----------------------------------------------------------------------===//
///
/// \file
/// \brief This file contains the WebAssembly implementation of the
/// WebAssemblyRegisterInfo class.
///
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIB_TARGET_WEBASSEMBLY_WEBASSEMBLYREGISTERINFO_H
#define LLVM_LIB_TARGET_WEBASSEMBLY_WEBASSEMBLYREGISTERINFO_H
#define GET_REGINFO_HEADER
#include "WebAssemblyGenRegisterInfo.inc"
namespace llvm {
class MachineFunction;
class RegScavenger;
class TargetRegisterClass;
class Triple;
class WebAssemblyRegisterInfo final : public WebAssemblyGenRegisterInfo {
const Triple &TT;
public:
explicit WebAssemblyRegisterInfo(const Triple &TT);
// Code Generation virtual methods.
const MCPhysReg *getCalleeSavedRegs(const MachineFunction *MF) const override;
BitVector getReservedRegs(const MachineFunction &MF) 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;
};
} // end namespace llvm
#endif