mirror of
https://github.com/c64scene-ar/llvm-6502.git
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226 lines
8.8 KiB
C++
226 lines
8.8 KiB
C++
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//===-- MipsSEFrameLowering.cpp - Mips32/64 Frame Information -------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file contains the Mips32/64 implementation of TargetFrameLowering class.
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//
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//===----------------------------------------------------------------------===//
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#include "MipsSEFrameLowering.h"
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#include "MipsAnalyzeImmediate.h"
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#include "MipsInstrInfo.h"
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#include "MipsMachineFunction.h"
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#include "MCTargetDesc/MipsBaseInfo.h"
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#include "llvm/Function.h"
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#include "llvm/CodeGen/MachineFrameInfo.h"
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#include "llvm/CodeGen/MachineFunction.h"
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#include "llvm/CodeGen/MachineInstrBuilder.h"
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#include "llvm/CodeGen/MachineModuleInfo.h"
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#include "llvm/CodeGen/MachineRegisterInfo.h"
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#include "llvm/Target/TargetData.h"
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#include "llvm/Target/TargetOptions.h"
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#include "llvm/Support/CommandLine.h"
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using namespace llvm;
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void MipsSEFrameLowering::emitPrologue(MachineFunction &MF) const {
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MachineBasicBlock &MBB = MF.front();
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MachineFrameInfo *MFI = MF.getFrameInfo();
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const MipsRegisterInfo *RegInfo =
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static_cast<const MipsRegisterInfo*>(MF.getTarget().getRegisterInfo());
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const MipsInstrInfo &TII =
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*static_cast<const MipsInstrInfo*>(MF.getTarget().getInstrInfo());
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MachineBasicBlock::iterator MBBI = MBB.begin();
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DebugLoc dl = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
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unsigned SP = STI.isABI_N64() ? Mips::SP_64 : Mips::SP;
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unsigned FP = STI.isABI_N64() ? Mips::FP_64 : Mips::FP;
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unsigned ZERO = STI.isABI_N64() ? Mips::ZERO_64 : Mips::ZERO;
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unsigned ADDu = STI.isABI_N64() ? Mips::DADDu : Mips::ADDu;
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unsigned ADDiu = STI.isABI_N64() ? Mips::DADDiu : Mips::ADDiu;
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// First, compute final stack size.
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uint64_t StackSize = MFI->getStackSize();
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// No need to allocate space on the stack.
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if (StackSize == 0 && !MFI->adjustsStack()) return;
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MachineModuleInfo &MMI = MF.getMMI();
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std::vector<MachineMove> &Moves = MMI.getFrameMoves();
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MachineLocation DstML, SrcML;
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// Adjust stack.
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if (isInt<16>(-StackSize))// addi sp, sp, (-stacksize)
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BuildMI(MBB, MBBI, dl, TII.get(ADDiu), SP).addReg(SP).addImm(-StackSize);
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else { // Expand immediate that doesn't fit in 16-bit.
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unsigned ATReg = STI.isABI_N64() ? Mips::AT_64 : Mips::AT;
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MF.getInfo<MipsFunctionInfo>()->setEmitNOAT();
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Mips::loadImmediate(-StackSize, STI.isABI_N64(), TII, MBB, MBBI, dl, false,
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0);
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BuildMI(MBB, MBBI, dl, TII.get(ADDu), SP).addReg(SP).addReg(ATReg);
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}
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// emit ".cfi_def_cfa_offset StackSize"
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MCSymbol *AdjustSPLabel = MMI.getContext().CreateTempSymbol();
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BuildMI(MBB, MBBI, dl,
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TII.get(TargetOpcode::PROLOG_LABEL)).addSym(AdjustSPLabel);
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DstML = MachineLocation(MachineLocation::VirtualFP);
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SrcML = MachineLocation(MachineLocation::VirtualFP, -StackSize);
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Moves.push_back(MachineMove(AdjustSPLabel, DstML, SrcML));
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const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();
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if (CSI.size()) {
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// Find the instruction past the last instruction that saves a callee-saved
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// register to the stack.
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for (unsigned i = 0; i < CSI.size(); ++i)
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++MBBI;
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// Iterate over list of callee-saved registers and emit .cfi_offset
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// directives.
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MCSymbol *CSLabel = MMI.getContext().CreateTempSymbol();
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BuildMI(MBB, MBBI, dl,
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TII.get(TargetOpcode::PROLOG_LABEL)).addSym(CSLabel);
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for (std::vector<CalleeSavedInfo>::const_iterator I = CSI.begin(),
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E = CSI.end(); I != E; ++I) {
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int64_t Offset = MFI->getObjectOffset(I->getFrameIdx());
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unsigned Reg = I->getReg();
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// If Reg is a double precision register, emit two cfa_offsets,
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// one for each of the paired single precision registers.
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if (Mips::AFGR64RegClass.contains(Reg)) {
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MachineLocation DstML0(MachineLocation::VirtualFP, Offset);
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MachineLocation DstML1(MachineLocation::VirtualFP, Offset + 4);
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MachineLocation SrcML0(RegInfo->getSubReg(Reg, Mips::sub_fpeven));
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MachineLocation SrcML1(RegInfo->getSubReg(Reg, Mips::sub_fpodd));
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if (!STI.isLittle())
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std::swap(SrcML0, SrcML1);
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Moves.push_back(MachineMove(CSLabel, DstML0, SrcML0));
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Moves.push_back(MachineMove(CSLabel, DstML1, SrcML1));
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} else {
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// Reg is either in CPURegs or FGR32.
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DstML = MachineLocation(MachineLocation::VirtualFP, Offset);
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SrcML = MachineLocation(Reg);
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Moves.push_back(MachineMove(CSLabel, DstML, SrcML));
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}
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}
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}
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// if framepointer enabled, set it to point to the stack pointer.
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if (hasFP(MF)) {
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// Insert instruction "move $fp, $sp" at this location.
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BuildMI(MBB, MBBI, dl, TII.get(ADDu), FP).addReg(SP).addReg(ZERO);
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// emit ".cfi_def_cfa_register $fp"
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MCSymbol *SetFPLabel = MMI.getContext().CreateTempSymbol();
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BuildMI(MBB, MBBI, dl,
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TII.get(TargetOpcode::PROLOG_LABEL)).addSym(SetFPLabel);
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DstML = MachineLocation(FP);
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SrcML = MachineLocation(MachineLocation::VirtualFP);
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Moves.push_back(MachineMove(SetFPLabel, DstML, SrcML));
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}
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}
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void MipsSEFrameLowering::emitEpilogue(MachineFunction &MF,
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MachineBasicBlock &MBB) const {
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MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
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MachineFrameInfo *MFI = MF.getFrameInfo();
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const MipsInstrInfo &TII =
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*static_cast<const MipsInstrInfo*>(MF.getTarget().getInstrInfo());
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DebugLoc dl = MBBI->getDebugLoc();
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unsigned SP = STI.isABI_N64() ? Mips::SP_64 : Mips::SP;
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unsigned FP = STI.isABI_N64() ? Mips::FP_64 : Mips::FP;
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unsigned ZERO = STI.isABI_N64() ? Mips::ZERO_64 : Mips::ZERO;
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unsigned ADDu = STI.isABI_N64() ? Mips::DADDu : Mips::ADDu;
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unsigned ADDiu = STI.isABI_N64() ? Mips::DADDiu : Mips::ADDiu;
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// if framepointer enabled, restore the stack pointer.
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if (hasFP(MF)) {
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// Find the first instruction that restores a callee-saved register.
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MachineBasicBlock::iterator I = MBBI;
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for (unsigned i = 0; i < MFI->getCalleeSavedInfo().size(); ++i)
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--I;
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// Insert instruction "move $sp, $fp" at this location.
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BuildMI(MBB, I, dl, TII.get(ADDu), SP).addReg(FP).addReg(ZERO);
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}
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// Get the number of bytes from FrameInfo
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uint64_t StackSize = MFI->getStackSize();
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if (!StackSize)
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return;
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// Adjust stack.
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if (isInt<16>(StackSize)) // addi sp, sp, (-stacksize)
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BuildMI(MBB, MBBI, dl, TII.get(ADDiu), SP).addReg(SP).addImm(StackSize);
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else { // Expand immediate that doesn't fit in 16-bit.
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unsigned ATReg = STI.isABI_N64() ? Mips::AT_64 : Mips::AT;
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MF.getInfo<MipsFunctionInfo>()->setEmitNOAT();
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Mips::loadImmediate(StackSize, STI.isABI_N64(), TII, MBB, MBBI, dl, false,
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0);
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BuildMI(MBB, MBBI, dl, TII.get(ADDu), SP).addReg(SP).addReg(ATReg);
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}
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}
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bool MipsSEFrameLowering::
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spillCalleeSavedRegisters(MachineBasicBlock &MBB,
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MachineBasicBlock::iterator MI,
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const std::vector<CalleeSavedInfo> &CSI,
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const TargetRegisterInfo *TRI) const {
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MachineFunction *MF = MBB.getParent();
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MachineBasicBlock *EntryBlock = MF->begin();
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const TargetInstrInfo &TII = *MF->getTarget().getInstrInfo();
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for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
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// Add the callee-saved register as live-in. Do not add if the register is
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// RA and return address is taken, because it has already been added in
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// method MipsTargetLowering::LowerRETURNADDR.
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// It's killed at the spill, unless the register is RA and return address
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// is taken.
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unsigned Reg = CSI[i].getReg();
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bool IsRAAndRetAddrIsTaken = (Reg == Mips::RA || Reg == Mips::RA_64)
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&& MF->getFrameInfo()->isReturnAddressTaken();
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if (!IsRAAndRetAddrIsTaken)
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EntryBlock->addLiveIn(Reg);
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// Insert the spill to the stack frame.
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bool IsKill = !IsRAAndRetAddrIsTaken;
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const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
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TII.storeRegToStackSlot(*EntryBlock, MI, Reg, IsKill,
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CSI[i].getFrameIdx(), RC, TRI);
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}
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return true;
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}
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bool
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MipsSEFrameLowering::hasReservedCallFrame(const MachineFunction &MF) const {
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const MachineFrameInfo *MFI = MF.getFrameInfo();
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// Reserve call frame if the size of the maximum call frame fits into 16-bit
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// immediate field and there are no variable sized objects on the stack.
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return isInt<16>(MFI->getMaxCallFrameSize()) && !MFI->hasVarSizedObjects();
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}
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void MipsSEFrameLowering::
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processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
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RegScavenger *RS) const {
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MachineRegisterInfo &MRI = MF.getRegInfo();
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unsigned FP = STI.isABI_N64() ? Mips::FP_64 : Mips::FP;
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// Mark $fp as used if function has dedicated frame pointer.
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if (hasFP(MF))
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MRI.setPhysRegUsed(FP);
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}
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