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helper functions. This can be optimized out later when the remaining parts of the helper function work is moved into the Mips16HardFloat pass. For now it forces us to use the 32 bit save/restore instructions instead of the 16 bit ones. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187712 91177308-0d34-0410-b5e6-96231b3b80d8
181 lines
6.4 KiB
C++
181 lines
6.4 KiB
C++
//===-- Mips16FrameLowering.cpp - Mips16 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 Mips16 implementation of TargetFrameLowering class.
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//
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//===----------------------------------------------------------------------===//
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#include "Mips16FrameLowering.h"
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#include "MCTargetDesc/MipsBaseInfo.h"
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#include "Mips16InstrInfo.h"
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#include "MipsInstrInfo.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/IR/DataLayout.h"
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#include "llvm/IR/Function.h"
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#include "llvm/Support/CommandLine.h"
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#include "llvm/Target/TargetOptions.h"
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using namespace llvm;
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void Mips16FrameLowering::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 Mips16InstrInfo &TII =
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*static_cast<const Mips16InstrInfo*>(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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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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const MCRegisterInfo *MRI = MMI.getContext().getRegisterInfo();
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MachineLocation DstML, SrcML;
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// Adjust stack.
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TII.makeFrame(Mips::SP, StackSize, MBB, MBBI);
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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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MMI.addFrameInst(
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MCCFIInstruction::createDefCfaOffset(AdjustSPLabel, -StackSize));
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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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unsigned S2 = MRI->getDwarfRegNum(Mips::S2, true);
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MMI.addFrameInst(MCCFIInstruction::createOffset(CSLabel, S2, -8));
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unsigned S1 = MRI->getDwarfRegNum(Mips::S1, true);
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MMI.addFrameInst(MCCFIInstruction::createOffset(CSLabel, S1, -12));
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unsigned S0 = MRI->getDwarfRegNum(Mips::S0, true);
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MMI.addFrameInst(MCCFIInstruction::createOffset(CSLabel, S0, -16));
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unsigned RA = MRI->getDwarfRegNum(Mips::RA, true);
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MMI.addFrameInst(MCCFIInstruction::createOffset(CSLabel, RA, -4));
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if (hasFP(MF))
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BuildMI(MBB, MBBI, dl, TII.get(Mips::MoveR3216), Mips::S0)
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.addReg(Mips::SP);
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}
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void Mips16FrameLowering::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 Mips16InstrInfo &TII =
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*static_cast<const Mips16InstrInfo*>(MF.getTarget().getInstrInfo());
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DebugLoc dl = MBBI->getDebugLoc();
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uint64_t StackSize = MFI->getStackSize();
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if (!StackSize)
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return;
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if (hasFP(MF))
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BuildMI(MBB, MBBI, dl, TII.get(Mips::Move32R16), Mips::SP)
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.addReg(Mips::S0);
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// Adjust stack.
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// assumes stacksize multiple of 8
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TII.restoreFrame(Mips::SP, StackSize, MBB, MBBI);
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}
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bool Mips16FrameLowering::
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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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//
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// Registers RA, S0,S1 are the callee saved registers and they
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// will be saved with the "save" instruction
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// during emitPrologue
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//
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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)
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&& MF->getFrameInfo()->isReturnAddressTaken();
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if (!IsRAAndRetAddrIsTaken)
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EntryBlock->addLiveIn(Reg);
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}
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return true;
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}
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bool Mips16FrameLowering::restoreCalleeSavedRegisters(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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//
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// Registers RA,S0,S1 are the callee saved registers and they will be restored
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// with the restore instruction during emitEpilogue.
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// We need to override this virtual function, otherwise llvm will try and
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// restore the registers on it's on from the stack.
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//
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return true;
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}
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// Eliminate ADJCALLSTACKDOWN, ADJCALLSTACKUP pseudo instructions
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void Mips16FrameLowering::
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eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
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MachineBasicBlock::iterator I) const {
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if (!hasReservedCallFrame(MF)) {
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int64_t Amount = I->getOperand(0).getImm();
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if (I->getOpcode() == Mips::ADJCALLSTACKDOWN)
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Amount = -Amount;
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const Mips16InstrInfo &TII =
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*static_cast<const Mips16InstrInfo*>(MF.getTarget().getInstrInfo());
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TII.adjustStackPtr(Mips::SP, Amount, MBB, I);
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}
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MBB.erase(I);
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}
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bool
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Mips16FrameLowering::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 15-bit
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// immediate field and there are no variable sized objects on the stack.
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return isInt<15>(MFI->getMaxCallFrameSize()) && !MFI->hasVarSizedObjects();
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}
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void Mips16FrameLowering::
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processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
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RegScavenger *RS) const {
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MF.getRegInfo().setPhysRegUsed(Mips::RA);
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MF.getRegInfo().setPhysRegUsed(Mips::S0);
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MF.getRegInfo().setPhysRegUsed(Mips::S1);
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MF.getRegInfo().setPhysRegUsed(Mips::S2);
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}
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const MipsFrameLowering *
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llvm::createMips16FrameLowering(const MipsSubtarget &ST) {
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return new Mips16FrameLowering(ST);
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}
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