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We have a detailed def/use lists for every physical register in MachineRegisterInfo anyway, so there is little use in maintaining an additional bitset of which ones are used. Removing it frees us from extra book keeping. This simplifies VirtRegMap. Differential Revision: http://reviews.llvm.org/D10911 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@242173 91177308-0d34-0410-b5e6-96231b3b80d8
259 lines
8.9 KiB
C++
259 lines
8.9 KiB
C++
//===-- SparcFrameLowering.cpp - Sparc 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 Sparc implementation of TargetFrameLowering class.
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//
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//===----------------------------------------------------------------------===//
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#include "SparcFrameLowering.h"
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#include "SparcInstrInfo.h"
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#include "SparcMachineFunctionInfo.h"
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#include "SparcSubtarget.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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static cl::opt<bool>
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DisableLeafProc("disable-sparc-leaf-proc",
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cl::init(false),
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cl::desc("Disable Sparc leaf procedure optimization."),
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cl::Hidden);
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SparcFrameLowering::SparcFrameLowering(const SparcSubtarget &ST)
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: TargetFrameLowering(TargetFrameLowering::StackGrowsDown,
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ST.is64Bit() ? 16 : 8, 0, ST.is64Bit() ? 16 : 8) {}
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void SparcFrameLowering::emitSPAdjustment(MachineFunction &MF,
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MachineBasicBlock &MBB,
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MachineBasicBlock::iterator MBBI,
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int NumBytes,
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unsigned ADDrr,
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unsigned ADDri) const {
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DebugLoc dl = (MBBI != MBB.end()) ? MBBI->getDebugLoc() : DebugLoc();
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const SparcInstrInfo &TII =
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*static_cast<const SparcInstrInfo *>(MF.getSubtarget().getInstrInfo());
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if (NumBytes >= -4096 && NumBytes < 4096) {
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BuildMI(MBB, MBBI, dl, TII.get(ADDri), SP::O6)
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.addReg(SP::O6).addImm(NumBytes);
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return;
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}
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// Emit this the hard way. This clobbers G1 which we always know is
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// available here.
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if (NumBytes >= 0) {
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// Emit nonnegative numbers with sethi + or.
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// sethi %hi(NumBytes), %g1
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// or %g1, %lo(NumBytes), %g1
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// add %sp, %g1, %sp
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BuildMI(MBB, MBBI, dl, TII.get(SP::SETHIi), SP::G1)
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.addImm(HI22(NumBytes));
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BuildMI(MBB, MBBI, dl, TII.get(SP::ORri), SP::G1)
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.addReg(SP::G1).addImm(LO10(NumBytes));
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BuildMI(MBB, MBBI, dl, TII.get(ADDrr), SP::O6)
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.addReg(SP::O6).addReg(SP::G1);
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return ;
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}
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// Emit negative numbers with sethi + xor.
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// sethi %hix(NumBytes), %g1
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// xor %g1, %lox(NumBytes), %g1
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// add %sp, %g1, %sp
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BuildMI(MBB, MBBI, dl, TII.get(SP::SETHIi), SP::G1)
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.addImm(HIX22(NumBytes));
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BuildMI(MBB, MBBI, dl, TII.get(SP::XORri), SP::G1)
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.addReg(SP::G1).addImm(LOX10(NumBytes));
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BuildMI(MBB, MBBI, dl, TII.get(ADDrr), SP::O6)
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.addReg(SP::O6).addReg(SP::G1);
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}
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void SparcFrameLowering::emitPrologue(MachineFunction &MF,
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MachineBasicBlock &MBB) const {
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SparcMachineFunctionInfo *FuncInfo = MF.getInfo<SparcMachineFunctionInfo>();
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assert(&MF.front() == &MBB && "Shrink-wrapping not yet supported");
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MachineFrameInfo *MFI = MF.getFrameInfo();
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const SparcInstrInfo &TII =
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*static_cast<const SparcInstrInfo *>(MF.getSubtarget().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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// Get the number of bytes to allocate from the FrameInfo
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int NumBytes = (int) MFI->getStackSize();
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unsigned SAVEri = SP::SAVEri;
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unsigned SAVErr = SP::SAVErr;
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if (FuncInfo->isLeafProc()) {
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if (NumBytes == 0)
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return;
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SAVEri = SP::ADDri;
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SAVErr = SP::ADDrr;
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}
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NumBytes = -MF.getSubtarget<SparcSubtarget>().getAdjustedFrameSize(NumBytes);
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emitSPAdjustment(MF, MBB, MBBI, NumBytes, SAVErr, SAVEri);
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MachineModuleInfo &MMI = MF.getMMI();
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const MCRegisterInfo *MRI = MMI.getContext().getRegisterInfo();
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unsigned regFP = MRI->getDwarfRegNum(SP::I6, true);
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// Emit ".cfi_def_cfa_register 30".
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unsigned CFIIndex =
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MMI.addFrameInst(MCCFIInstruction::createDefCfaRegister(nullptr, regFP));
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BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION))
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.addCFIIndex(CFIIndex);
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// Emit ".cfi_window_save".
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CFIIndex = MMI.addFrameInst(MCCFIInstruction::createWindowSave(nullptr));
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BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION))
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.addCFIIndex(CFIIndex);
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unsigned regInRA = MRI->getDwarfRegNum(SP::I7, true);
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unsigned regOutRA = MRI->getDwarfRegNum(SP::O7, true);
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// Emit ".cfi_register 15, 31".
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CFIIndex = MMI.addFrameInst(
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MCCFIInstruction::createRegister(nullptr, regOutRA, regInRA));
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BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION))
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.addCFIIndex(CFIIndex);
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}
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void SparcFrameLowering::
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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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MachineInstr &MI = *I;
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int Size = MI.getOperand(0).getImm();
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if (MI.getOpcode() == SP::ADJCALLSTACKDOWN)
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Size = -Size;
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if (Size)
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emitSPAdjustment(MF, MBB, I, Size, SP::ADDrr, SP::ADDri);
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}
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MBB.erase(I);
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}
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void SparcFrameLowering::emitEpilogue(MachineFunction &MF,
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MachineBasicBlock &MBB) const {
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SparcMachineFunctionInfo *FuncInfo = MF.getInfo<SparcMachineFunctionInfo>();
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MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
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const SparcInstrInfo &TII =
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*static_cast<const SparcInstrInfo *>(MF.getSubtarget().getInstrInfo());
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DebugLoc dl = MBBI->getDebugLoc();
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assert(MBBI->getOpcode() == SP::RETL &&
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"Can only put epilog before 'retl' instruction!");
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if (!FuncInfo->isLeafProc()) {
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BuildMI(MBB, MBBI, dl, TII.get(SP::RESTORErr), SP::G0).addReg(SP::G0)
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.addReg(SP::G0);
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return;
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}
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MachineFrameInfo *MFI = MF.getFrameInfo();
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int NumBytes = (int) MFI->getStackSize();
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if (NumBytes == 0)
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return;
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NumBytes = MF.getSubtarget<SparcSubtarget>().getAdjustedFrameSize(NumBytes);
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emitSPAdjustment(MF, MBB, MBBI, NumBytes, SP::ADDrr, SP::ADDri);
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}
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bool SparcFrameLowering::hasReservedCallFrame(const MachineFunction &MF) const {
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// Reserve call frame if there are no variable sized objects on the stack.
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return !MF.getFrameInfo()->hasVarSizedObjects();
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}
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// hasFP - Return true if the specified function should have a dedicated frame
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// pointer register. This is true if the function has variable sized allocas or
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// if frame pointer elimination is disabled.
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bool SparcFrameLowering::hasFP(const MachineFunction &MF) const {
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const MachineFrameInfo *MFI = MF.getFrameInfo();
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return MF.getTarget().Options.DisableFramePointerElim(MF) ||
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MFI->hasVarSizedObjects() || MFI->isFrameAddressTaken();
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}
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static bool LLVM_ATTRIBUTE_UNUSED verifyLeafProcRegUse(MachineRegisterInfo *MRI)
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{
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for (unsigned reg = SP::I0; reg <= SP::I7; ++reg)
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if (!MRI->reg_nodbg_empty(reg))
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return false;
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for (unsigned reg = SP::L0; reg <= SP::L7; ++reg)
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if (!MRI->reg_nodbg_empty(reg))
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return false;
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return true;
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}
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bool SparcFrameLowering::isLeafProc(MachineFunction &MF) const
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{
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MachineRegisterInfo &MRI = MF.getRegInfo();
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MachineFrameInfo *MFI = MF.getFrameInfo();
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return !(MFI->hasCalls() // has calls
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|| !MRI.reg_nodbg_empty(SP::L0) // Too many registers needed
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|| !MRI.reg_nodbg_empty(SP::O6) // %SP is used
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|| hasFP(MF)); // need %FP
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}
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void SparcFrameLowering::remapRegsForLeafProc(MachineFunction &MF) const {
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MachineRegisterInfo &MRI = MF.getRegInfo();
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// Remap %i[0-7] to %o[0-7].
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for (unsigned reg = SP::I0; reg <= SP::I7; ++reg) {
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if (MRI.reg_nodbg_empty(reg))
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continue;
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unsigned mapped_reg = (reg - SP::I0 + SP::O0);
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assert(MRI.reg_nodbg_empty(mapped_reg));
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// Replace I register with O register.
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MRI.replaceRegWith(reg, mapped_reg);
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}
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// Rewrite MBB's Live-ins.
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for (MachineFunction::iterator MBB = MF.begin(), E = MF.end();
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MBB != E; ++MBB) {
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for (unsigned reg = SP::I0; reg <= SP::I7; ++reg) {
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if (!MBB->isLiveIn(reg))
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continue;
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MBB->removeLiveIn(reg);
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MBB->addLiveIn(reg - SP::I0 + SP::O0);
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}
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}
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assert(verifyLeafProcRegUse(&MRI));
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#ifdef XDEBUG
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MF.verify(0, "After LeafProc Remapping");
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#endif
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}
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void SparcFrameLowering::determineCalleeSaves(MachineFunction &MF,
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BitVector &SavedRegs,
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RegScavenger *RS) const {
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TargetFrameLowering::determineCalleeSaves(MF, SavedRegs, RS);
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if (!DisableLeafProc && isLeafProc(MF)) {
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SparcMachineFunctionInfo *MFI = MF.getInfo<SparcMachineFunctionInfo>();
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MFI->setLeafProc(true);
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remapRegsForLeafProc(MF);
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}
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}
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