llvm/lib/Target/ARM/ARMInstrInfo.cpp
Sam Parker fcb98b7928 [ARM] Add OptMinSize to ARMSubtarget
In many places in the backend, we like to know whether we're
optimising for code size and this is performed by checking the
current machine function attributes. A subtarget is created on a
per-function basis, so it's possible to know when we're compiling for
code size on construction so record this in the new object.

Differential Revision: https://reviews.llvm.org/D57812


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@353501 91177308-0d34-0410-b5e6-96231b3b80d8
2019-02-08 07:57:42 +00:00

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4.2 KiB
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//===-- ARMInstrInfo.cpp - ARM Instruction Information --------------------===//
//
// 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 file contains the ARM implementation of the TargetInstrInfo class.
//
//===----------------------------------------------------------------------===//
#include "ARMInstrInfo.h"
#include "ARM.h"
#include "ARMConstantPoolValue.h"
#include "ARMMachineFunctionInfo.h"
#include "ARMTargetMachine.h"
#include "MCTargetDesc/ARMAddressingModes.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/CodeGen/LiveVariables.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineJumpTableInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCInst.h"
using namespace llvm;
ARMInstrInfo::ARMInstrInfo(const ARMSubtarget &STI)
: ARMBaseInstrInfo(STI), RI() {}
/// Return the noop instruction to use for a noop.
void ARMInstrInfo::getNoop(MCInst &NopInst) const {
if (hasNOP()) {
NopInst.setOpcode(ARM::HINT);
NopInst.addOperand(MCOperand::createImm(0));
NopInst.addOperand(MCOperand::createImm(ARMCC::AL));
NopInst.addOperand(MCOperand::createReg(0));
} else {
NopInst.setOpcode(ARM::MOVr);
NopInst.addOperand(MCOperand::createReg(ARM::R0));
NopInst.addOperand(MCOperand::createReg(ARM::R0));
NopInst.addOperand(MCOperand::createImm(ARMCC::AL));
NopInst.addOperand(MCOperand::createReg(0));
NopInst.addOperand(MCOperand::createReg(0));
}
}
unsigned ARMInstrInfo::getUnindexedOpcode(unsigned Opc) const {
switch (Opc) {
default:
break;
case ARM::LDR_PRE_IMM:
case ARM::LDR_PRE_REG:
case ARM::LDR_POST_IMM:
case ARM::LDR_POST_REG:
return ARM::LDRi12;
case ARM::LDRH_PRE:
case ARM::LDRH_POST:
return ARM::LDRH;
case ARM::LDRB_PRE_IMM:
case ARM::LDRB_PRE_REG:
case ARM::LDRB_POST_IMM:
case ARM::LDRB_POST_REG:
return ARM::LDRBi12;
case ARM::LDRSH_PRE:
case ARM::LDRSH_POST:
return ARM::LDRSH;
case ARM::LDRSB_PRE:
case ARM::LDRSB_POST:
return ARM::LDRSB;
case ARM::STR_PRE_IMM:
case ARM::STR_PRE_REG:
case ARM::STR_POST_IMM:
case ARM::STR_POST_REG:
return ARM::STRi12;
case ARM::STRH_PRE:
case ARM::STRH_POST:
return ARM::STRH;
case ARM::STRB_PRE_IMM:
case ARM::STRB_PRE_REG:
case ARM::STRB_POST_IMM:
case ARM::STRB_POST_REG:
return ARM::STRBi12;
}
return 0;
}
void ARMInstrInfo::expandLoadStackGuard(MachineBasicBlock::iterator MI) const {
MachineFunction &MF = *MI->getParent()->getParent();
const ARMSubtarget &Subtarget = MF.getSubtarget<ARMSubtarget>();
const TargetMachine &TM = MF.getTarget();
if (!Subtarget.useMovt()) {
if (TM.isPositionIndependent())
expandLoadStackGuardBase(MI, ARM::LDRLIT_ga_pcrel, ARM::LDRi12);
else
expandLoadStackGuardBase(MI, ARM::LDRLIT_ga_abs, ARM::LDRi12);
return;
}
if (!TM.isPositionIndependent()) {
expandLoadStackGuardBase(MI, ARM::MOVi32imm, ARM::LDRi12);
return;
}
const GlobalValue *GV =
cast<GlobalValue>((*MI->memoperands_begin())->getValue());
if (!Subtarget.isGVIndirectSymbol(GV)) {
expandLoadStackGuardBase(MI, ARM::MOV_ga_pcrel, ARM::LDRi12);
return;
}
MachineBasicBlock &MBB = *MI->getParent();
DebugLoc DL = MI->getDebugLoc();
unsigned Reg = MI->getOperand(0).getReg();
MachineInstrBuilder MIB;
MIB = BuildMI(MBB, MI, DL, get(ARM::MOV_ga_pcrel_ldr), Reg)
.addGlobalAddress(GV, 0, ARMII::MO_NONLAZY);
auto Flags = MachineMemOperand::MOLoad |
MachineMemOperand::MODereferenceable |
MachineMemOperand::MOInvariant;
MachineMemOperand *MMO = MBB.getParent()->getMachineMemOperand(
MachinePointerInfo::getGOT(*MBB.getParent()), Flags, 4, 4);
MIB.addMemOperand(MMO);
BuildMI(MBB, MI, DL, get(ARM::LDRi12), Reg)
.addReg(Reg, RegState::Kill)
.addImm(0)
.cloneMemRefs(*MI)
.add(predOps(ARMCC::AL));
}