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//===-- RISCVRegisterInfo.cpp - RISCV Register Information ------*- 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 file contains the RISCV implementation of the TargetRegisterInfo class.
//
//===----------------------------------------------------------------------===//
#include "RISCVRegisterInfo.h"
#include "RISCV.h"
#include "RISCVMachineFunctionInfo.h"
#include "RISCVSubtarget.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/RegisterScavenging.h"
#include "llvm/CodeGen/TargetFrameLowering.h"
#include "llvm/CodeGen/TargetInstrInfo.h"
#include "llvm/Support/ErrorHandling.h"
#define GET_REGINFO_TARGET_DESC
#include "RISCVGenRegisterInfo.inc"
using namespace llvm;
static_assert(RISCV::X1 == RISCV::X0 + 1, "Register list not consecutive");
static_assert(RISCV::X31 == RISCV::X0 + 31, "Register list not consecutive");
static_assert(RISCV::F1_F == RISCV::F0_F + 1, "Register list not consecutive");
static_assert(RISCV::F31_F == RISCV::F0_F + 31,
"Register list not consecutive");
static_assert(RISCV::F1_D == RISCV::F0_D + 1, "Register list not consecutive");
static_assert(RISCV::F31_D == RISCV::F0_D + 31,
"Register list not consecutive");
static_assert(RISCV::V1 == RISCV::V0 + 1, "Register list not consecutive");
static_assert(RISCV::V31 == RISCV::V0 + 31, "Register list not consecutive");
RISCVRegisterInfo::RISCVRegisterInfo(unsigned HwMode)
: RISCVGenRegisterInfo(RISCV::X1, /*DwarfFlavour*/0, /*EHFlavor*/0,
/*PC*/0, HwMode) {}
const MCPhysReg *
RISCVRegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {
auto &Subtarget = MF->getSubtarget<RISCVSubtarget>();
if (MF->getFunction().hasFnAttribute("interrupt")) {
if (Subtarget.hasStdExtD())
return CSR_XLEN_F64_Interrupt_SaveList;
if (Subtarget.hasStdExtF())
return CSR_XLEN_F32_Interrupt_SaveList;
return CSR_Interrupt_SaveList;
}
switch (Subtarget.getTargetABI()) {
default:
llvm_unreachable("Unrecognized ABI");
case RISCVABI::ABI_ILP32:
case RISCVABI::ABI_LP64:
return CSR_ILP32_LP64_SaveList;
case RISCVABI::ABI_ILP32F:
case RISCVABI::ABI_LP64F:
return CSR_ILP32F_LP64F_SaveList;
case RISCVABI::ABI_ILP32D:
case RISCVABI::ABI_LP64D:
return CSR_ILP32D_LP64D_SaveList;
}
}
BitVector RISCVRegisterInfo::getReservedRegs(const MachineFunction &MF) const {
const RISCVFrameLowering *TFI = getFrameLowering(MF);
BitVector Reserved(getNumRegs());
// Mark any registers requested to be reserved as such
for (size_t Reg = 0; Reg < getNumRegs(); Reg++) {
if (MF.getSubtarget<RISCVSubtarget>().isRegisterReservedByUser(Reg))
markSuperRegs(Reserved, Reg);
}
// Use markSuperRegs to ensure any register aliases are also reserved
markSuperRegs(Reserved, RISCV::X0); // zero
markSuperRegs(Reserved, RISCV::X2); // sp
markSuperRegs(Reserved, RISCV::X3); // gp
markSuperRegs(Reserved, RISCV::X4); // tp
if (TFI->hasFP(MF))
markSuperRegs(Reserved, RISCV::X8); // fp
// Reserve the base register if we need to realign the stack and allocate
// variable-sized objects at runtime.
if (TFI->hasBP(MF))
markSuperRegs(Reserved, RISCVABI::getBPReg()); // bp
assert(checkAllSuperRegsMarked(Reserved));
return Reserved;
}
bool RISCVRegisterInfo::isAsmClobberable(const MachineFunction &MF,
MCRegister PhysReg) const {
return !MF.getSubtarget<RISCVSubtarget>().isRegisterReservedByUser(PhysReg);
}
bool RISCVRegisterInfo::isConstantPhysReg(MCRegister PhysReg) const {
return PhysReg == RISCV::X0;
}
const uint32_t *RISCVRegisterInfo::getNoPreservedMask() const {
return CSR_NoRegs_RegMask;
}
// Frame indexes representing locations of CSRs which are given a fixed location
// by save/restore libcalls.
static const std::map<unsigned, int> FixedCSRFIMap = {
{/*ra*/ RISCV::X1, -1},
{/*s0*/ RISCV::X8, -2},
{/*s1*/ RISCV::X9, -3},
{/*s2*/ RISCV::X18, -4},
{/*s3*/ RISCV::X19, -5},
{/*s4*/ RISCV::X20, -6},
{/*s5*/ RISCV::X21, -7},
{/*s6*/ RISCV::X22, -8},
{/*s7*/ RISCV::X23, -9},
{/*s8*/ RISCV::X24, -10},
{/*s9*/ RISCV::X25, -11},
{/*s10*/ RISCV::X26, -12},
{/*s11*/ RISCV::X27, -13}
};
bool RISCVRegisterInfo::hasReservedSpillSlot(const MachineFunction &MF,
Register Reg,
int &FrameIdx) const {
const auto *RVFI = MF.getInfo<RISCVMachineFunctionInfo>();
if (!RVFI->useSaveRestoreLibCalls(MF))
return false;
auto FII = FixedCSRFIMap.find(Reg);
if (FII == FixedCSRFIMap.end())
return false;
FrameIdx = FII->second;
return true;
}
void RISCVRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
int SPAdj, unsigned FIOperandNum,
RegScavenger *RS) const {
assert(SPAdj == 0 && "Unexpected non-zero SPAdj value");
MachineInstr &MI = *II;
MachineFunction &MF = *MI.getParent()->getParent();
MachineRegisterInfo &MRI = MF.getRegInfo();
const RISCVInstrInfo *TII = MF.getSubtarget<RISCVSubtarget>().getInstrInfo();
DebugLoc DL = MI.getDebugLoc();
int FrameIndex = MI.getOperand(FIOperandNum).getIndex();
Register FrameReg;
int Offset =
getFrameLowering(MF)->getFrameIndexReference(MF, FrameIndex, FrameReg) +
MI.getOperand(FIOperandNum + 1).getImm();
if (!isInt<32>(Offset)) {
report_fatal_error(
"Frame offsets outside of the signed 32-bit range not supported");
}
MachineBasicBlock &MBB = *MI.getParent();
bool FrameRegIsKill = false;
if (!isInt<12>(Offset)) {
assert(isInt<32>(Offset) && "Int32 expected");
// The offset won't fit in an immediate, so use a scratch register instead
// Modify Offset and FrameReg appropriately
Register ScratchReg = MRI.createVirtualRegister(&RISCV::GPRRegClass);
TII->movImm(MBB, II, DL, ScratchReg, Offset);
BuildMI(MBB, II, DL, TII->get(RISCV::ADD), ScratchReg)
.addReg(FrameReg)
.addReg(ScratchReg, RegState::Kill);
Offset = 0;
FrameReg = ScratchReg;
FrameRegIsKill = true;
}
MI.getOperand(FIOperandNum)
.ChangeToRegister(FrameReg, false, false, FrameRegIsKill);
MI.getOperand(FIOperandNum + 1).ChangeToImmediate(Offset);
}
Register RISCVRegisterInfo::getFrameRegister(const MachineFunction &MF) const {
const TargetFrameLowering *TFI = getFrameLowering(MF);
return TFI->hasFP(MF) ? RISCV::X8 : RISCV::X2;
}
const uint32_t *
RISCVRegisterInfo::getCallPreservedMask(const MachineFunction & MF,
CallingConv::ID /*CC*/) const {
auto &Subtarget = MF.getSubtarget<RISCVSubtarget>();
switch (Subtarget.getTargetABI()) {
default:
llvm_unreachable("Unrecognized ABI");
case RISCVABI::ABI_ILP32:
case RISCVABI::ABI_LP64:
return CSR_ILP32_LP64_RegMask;
case RISCVABI::ABI_ILP32F:
case RISCVABI::ABI_LP64F:
return CSR_ILP32F_LP64F_RegMask;
case RISCVABI::ABI_ILP32D:
case RISCVABI::ABI_LP64D:
return CSR_ILP32D_LP64D_RegMask;
}
}
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