/3rd_party/llvm/lib/Target/Sparc/SparcFrameLowering.cpp
https://code.google.com/p/softart/ · C++ · 252 lines · 174 code · 44 blank · 34 comment · 32 complexity · 157a73f17dd2f3c4c2ab5b1f181e62b2 MD5 · raw file
- //===-- SparcFrameLowering.cpp - Sparc Frame Information ------------------===//
- //
- // The LLVM Compiler Infrastructure
- //
- // This file is distributed under the University of Illinois Open Source
- // License. See LICENSE.TXT for details.
- //
- //===----------------------------------------------------------------------===//
- //
- // This file contains the Sparc implementation of TargetFrameLowering class.
- //
- //===----------------------------------------------------------------------===//
- #include "SparcFrameLowering.h"
- #include "SparcInstrInfo.h"
- #include "SparcMachineFunctionInfo.h"
- #include "llvm/CodeGen/MachineFrameInfo.h"
- #include "llvm/CodeGen/MachineFunction.h"
- #include "llvm/CodeGen/MachineInstrBuilder.h"
- #include "llvm/CodeGen/MachineModuleInfo.h"
- #include "llvm/CodeGen/MachineRegisterInfo.h"
- #include "llvm/IR/DataLayout.h"
- #include "llvm/IR/Function.h"
- #include "llvm/Support/CommandLine.h"
- #include "llvm/Target/TargetOptions.h"
- using namespace llvm;
- static cl::opt<bool>
- DisableLeafProc("disable-sparc-leaf-proc",
- cl::init(false),
- cl::desc("Disable Sparc leaf procedure optimization."),
- cl::Hidden);
- void SparcFrameLowering::emitSPAdjustment(MachineFunction &MF,
- MachineBasicBlock &MBB,
- MachineBasicBlock::iterator MBBI,
- int NumBytes,
- unsigned ADDrr,
- unsigned ADDri) const {
- DebugLoc dl = (MBBI != MBB.end()) ? MBBI->getDebugLoc() : DebugLoc();
- const SparcInstrInfo &TII =
- *static_cast<const SparcInstrInfo*>(MF.getTarget().getInstrInfo());
- if (NumBytes >= -4096 && NumBytes < 4096) {
- BuildMI(MBB, MBBI, dl, TII.get(ADDri), SP::O6)
- .addReg(SP::O6).addImm(NumBytes);
- return;
- }
- // Emit this the hard way. This clobbers G1 which we always know is
- // available here.
- if (NumBytes >= 0) {
- // Emit nonnegative numbers with sethi + or.
- // sethi %hi(NumBytes), %g1
- // or %g1, %lo(NumBytes), %g1
- // add %sp, %g1, %sp
- BuildMI(MBB, MBBI, dl, TII.get(SP::SETHIi), SP::G1)
- .addImm(HI22(NumBytes));
- BuildMI(MBB, MBBI, dl, TII.get(SP::ORri), SP::G1)
- .addReg(SP::G1).addImm(LO10(NumBytes));
- BuildMI(MBB, MBBI, dl, TII.get(ADDrr), SP::O6)
- .addReg(SP::O6).addReg(SP::G1);
- return ;
- }
- // Emit negative numbers with sethi + xor.
- // sethi %hix(NumBytes), %g1
- // xor %g1, %lox(NumBytes), %g1
- // add %sp, %g1, %sp
- BuildMI(MBB, MBBI, dl, TII.get(SP::SETHIi), SP::G1)
- .addImm(HIX22(NumBytes));
- BuildMI(MBB, MBBI, dl, TII.get(SP::XORri), SP::G1)
- .addReg(SP::G1).addImm(LOX10(NumBytes));
- BuildMI(MBB, MBBI, dl, TII.get(ADDrr), SP::O6)
- .addReg(SP::O6).addReg(SP::G1);
- }
- void SparcFrameLowering::emitPrologue(MachineFunction &MF) const {
- SparcMachineFunctionInfo *FuncInfo = MF.getInfo<SparcMachineFunctionInfo>();
- MachineBasicBlock &MBB = MF.front();
- MachineFrameInfo *MFI = MF.getFrameInfo();
- const SparcInstrInfo &TII =
- *static_cast<const SparcInstrInfo*>(MF.getTarget().getInstrInfo());
- MachineBasicBlock::iterator MBBI = MBB.begin();
- DebugLoc dl = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
- // Get the number of bytes to allocate from the FrameInfo
- int NumBytes = (int) MFI->getStackSize();
- unsigned SAVEri = SP::SAVEri;
- unsigned SAVErr = SP::SAVErr;
- if (FuncInfo->isLeafProc()) {
- if (NumBytes == 0)
- return;
- SAVEri = SP::ADDri;
- SAVErr = SP::ADDrr;
- }
- NumBytes = - SubTarget.getAdjustedFrameSize(NumBytes);
- emitSPAdjustment(MF, MBB, MBBI, NumBytes, SAVErr, SAVEri);
- MachineModuleInfo &MMI = MF.getMMI();
- const MCRegisterInfo *MRI = MMI.getContext().getRegisterInfo();
- MCSymbol *FrameLabel = MMI.getContext().CreateTempSymbol();
- BuildMI(MBB, MBBI, dl, TII.get(SP::PROLOG_LABEL)).addSym(FrameLabel);
- unsigned regFP = MRI->getDwarfRegNum(SP::I6, true);
- // Emit ".cfi_def_cfa_register 30".
- MMI.addFrameInst(MCCFIInstruction::createDefCfaRegister(FrameLabel,
- regFP));
- // Emit ".cfi_window_save".
- MMI.addFrameInst(MCCFIInstruction::createWindowSave(FrameLabel));
- unsigned regInRA = MRI->getDwarfRegNum(SP::I7, true);
- unsigned regOutRA = MRI->getDwarfRegNum(SP::O7, true);
- // Emit ".cfi_register 15, 31".
- MMI.addFrameInst(MCCFIInstruction::createRegister(FrameLabel,
- regOutRA,
- regInRA));
- }
- void SparcFrameLowering::
- eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
- MachineBasicBlock::iterator I) const {
- if (!hasReservedCallFrame(MF)) {
- MachineInstr &MI = *I;
- int Size = MI.getOperand(0).getImm();
- if (MI.getOpcode() == SP::ADJCALLSTACKDOWN)
- Size = -Size;
- if (Size)
- emitSPAdjustment(MF, MBB, I, Size, SP::ADDrr, SP::ADDri);
- }
- MBB.erase(I);
- }
- void SparcFrameLowering::emitEpilogue(MachineFunction &MF,
- MachineBasicBlock &MBB) const {
- SparcMachineFunctionInfo *FuncInfo = MF.getInfo<SparcMachineFunctionInfo>();
- MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
- const SparcInstrInfo &TII =
- *static_cast<const SparcInstrInfo*>(MF.getTarget().getInstrInfo());
- DebugLoc dl = MBBI->getDebugLoc();
- assert(MBBI->getOpcode() == SP::RETL &&
- "Can only put epilog before 'retl' instruction!");
- if (!FuncInfo->isLeafProc()) {
- BuildMI(MBB, MBBI, dl, TII.get(SP::RESTORErr), SP::G0).addReg(SP::G0)
- .addReg(SP::G0);
- return;
- }
- MachineFrameInfo *MFI = MF.getFrameInfo();
- int NumBytes = (int) MFI->getStackSize();
- if (NumBytes == 0)
- return;
- NumBytes = SubTarget.getAdjustedFrameSize(NumBytes);
- emitSPAdjustment(MF, MBB, MBBI, NumBytes, SP::ADDrr, SP::ADDri);
- }
- bool SparcFrameLowering::hasReservedCallFrame(const MachineFunction &MF) const {
- // Reserve call frame if there are no variable sized objects on the stack.
- return !MF.getFrameInfo()->hasVarSizedObjects();
- }
- // hasFP - Return true if the specified function should have a dedicated frame
- // pointer register. This is true if the function has variable sized allocas or
- // if frame pointer elimination is disabled.
- bool SparcFrameLowering::hasFP(const MachineFunction &MF) const {
- const MachineFrameInfo *MFI = MF.getFrameInfo();
- return MF.getTarget().Options.DisableFramePointerElim(MF) ||
- MFI->hasVarSizedObjects() || MFI->isFrameAddressTaken();
- }
- static bool LLVM_ATTRIBUTE_UNUSED verifyLeafProcRegUse(MachineRegisterInfo *MRI)
- {
- for (unsigned reg = SP::I0; reg <= SP::I7; ++reg)
- if (MRI->isPhysRegUsed(reg))
- return false;
- for (unsigned reg = SP::L0; reg <= SP::L7; ++reg)
- if (MRI->isPhysRegUsed(reg))
- return false;
- return true;
- }
- bool SparcFrameLowering::isLeafProc(MachineFunction &MF) const
- {
- MachineRegisterInfo &MRI = MF.getRegInfo();
- MachineFrameInfo *MFI = MF.getFrameInfo();
- return !(MFI->hasCalls() // has calls
- || MRI.isPhysRegUsed(SP::L0) // Too many registers needed
- || MRI.isPhysRegUsed(SP::O6) // %SP is used
- || hasFP(MF)); // need %FP
- }
- void SparcFrameLowering::remapRegsForLeafProc(MachineFunction &MF) const {
- MachineRegisterInfo &MRI = MF.getRegInfo();
- // Remap %i[0-7] to %o[0-7].
- for (unsigned reg = SP::I0; reg <= SP::I7; ++reg) {
- if (!MRI.isPhysRegUsed(reg))
- continue;
- unsigned mapped_reg = (reg - SP::I0 + SP::O0);
- assert(!MRI.isPhysRegUsed(mapped_reg));
- // Replace I register with O register.
- MRI.replaceRegWith(reg, mapped_reg);
- // Mark the reg unused.
- MRI.setPhysRegUnused(reg);
- }
- // Rewrite MBB's Live-ins.
- for (MachineFunction::iterator MBB = MF.begin(), E = MF.end();
- MBB != E; ++MBB) {
- for (unsigned reg = SP::I0; reg <= SP::I7; ++reg) {
- if (!MBB->isLiveIn(reg))
- continue;
- MBB->removeLiveIn(reg);
- MBB->addLiveIn(reg - SP::I0 + SP::O0);
- }
- }
- assert(verifyLeafProcRegUse(&MRI));
- #ifdef XDEBUG
- MF.verify(0, "After LeafProc Remapping");
- #endif
- }
- void SparcFrameLowering::processFunctionBeforeCalleeSavedScan
- (MachineFunction &MF, RegScavenger *RS) const {
- if (!DisableLeafProc && isLeafProc(MF)) {
- SparcMachineFunctionInfo *MFI = MF.getInfo<SparcMachineFunctionInfo>();
- MFI->setLeafProc(true);
- remapRegsForLeafProc(MF);
- }
- }