SystemZRegisterInfo.cpp revision 263508
1//===-- SystemZRegisterInfo.cpp - SystemZ register information ------------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9 10#include "SystemZRegisterInfo.h" 11#include "SystemZTargetMachine.h" 12#include "llvm/CodeGen/MachineInstrBuilder.h" 13#include "llvm/CodeGen/MachineRegisterInfo.h" 14 15#define GET_REGINFO_TARGET_DESC 16#include "SystemZGenRegisterInfo.inc" 17 18using namespace llvm; 19 20SystemZRegisterInfo::SystemZRegisterInfo(SystemZTargetMachine &tm) 21 : SystemZGenRegisterInfo(SystemZ::R14D), TM(tm) {} 22 23const uint16_t* 24SystemZRegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const { 25 static const uint16_t CalleeSavedRegs[] = { 26 SystemZ::R6D, SystemZ::R7D, SystemZ::R8D, SystemZ::R9D, 27 SystemZ::R10D, SystemZ::R11D, SystemZ::R12D, SystemZ::R13D, 28 SystemZ::R14D, SystemZ::R15D, 29 SystemZ::F8D, SystemZ::F9D, SystemZ::F10D, SystemZ::F11D, 30 SystemZ::F12D, SystemZ::F13D, SystemZ::F14D, SystemZ::F15D, 31 0 32 }; 33 34 return CalleeSavedRegs; 35} 36 37BitVector 38SystemZRegisterInfo::getReservedRegs(const MachineFunction &MF) const { 39 BitVector Reserved(getNumRegs()); 40 const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering(); 41 42 if (TFI->hasFP(MF)) { 43 // R11D is the frame pointer. Reserve all aliases. 44 Reserved.set(SystemZ::R11D); 45 Reserved.set(SystemZ::R11L); 46 Reserved.set(SystemZ::R11H); 47 Reserved.set(SystemZ::R10Q); 48 } 49 50 // R15D is the stack pointer. Reserve all aliases. 51 Reserved.set(SystemZ::R15D); 52 Reserved.set(SystemZ::R15L); 53 Reserved.set(SystemZ::R15H); 54 Reserved.set(SystemZ::R14Q); 55 return Reserved; 56} 57 58void 59SystemZRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator MI, 60 int SPAdj, unsigned FIOperandNum, 61 RegScavenger *RS) const { 62 assert(SPAdj == 0 && "Outgoing arguments should be part of the frame"); 63 64 MachineBasicBlock &MBB = *MI->getParent(); 65 MachineFunction &MF = *MBB.getParent(); 66 const SystemZInstrInfo &TII = 67 *static_cast<const SystemZInstrInfo*>(TM.getInstrInfo()); 68 const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering(); 69 DebugLoc DL = MI->getDebugLoc(); 70 71 // Decompose the frame index into a base and offset. 72 int FrameIndex = MI->getOperand(FIOperandNum).getIndex(); 73 unsigned BasePtr = getFrameRegister(MF); 74 int64_t Offset = (TFI->getFrameIndexOffset(MF, FrameIndex) + 75 MI->getOperand(FIOperandNum + 1).getImm()); 76 77 // Special handling of dbg_value instructions. 78 if (MI->isDebugValue()) { 79 MI->getOperand(FIOperandNum).ChangeToRegister(BasePtr, /*isDef*/ false); 80 MI->getOperand(FIOperandNum + 1).ChangeToImmediate(Offset); 81 return; 82 } 83 84 // See if the offset is in range, or if an equivalent instruction that 85 // accepts the offset exists. 86 unsigned Opcode = MI->getOpcode(); 87 unsigned OpcodeForOffset = TII.getOpcodeForOffset(Opcode, Offset); 88 if (OpcodeForOffset) 89 MI->getOperand(FIOperandNum).ChangeToRegister(BasePtr, false); 90 else { 91 // Create an anchor point that is in range. Start at 0xffff so that 92 // can use LLILH to load the immediate. 93 int64_t OldOffset = Offset; 94 int64_t Mask = 0xffff; 95 do { 96 Offset = OldOffset & Mask; 97 OpcodeForOffset = TII.getOpcodeForOffset(Opcode, Offset); 98 Mask >>= 1; 99 assert(Mask && "One offset must be OK"); 100 } while (!OpcodeForOffset); 101 102 unsigned ScratchReg = 103 MF.getRegInfo().createVirtualRegister(&SystemZ::ADDR64BitRegClass); 104 int64_t HighOffset = OldOffset - Offset; 105 106 if (MI->getDesc().TSFlags & SystemZII::HasIndex 107 && MI->getOperand(FIOperandNum + 2).getReg() == 0) { 108 // Load the offset into the scratch register and use it as an index. 109 // The scratch register then dies here. 110 TII.loadImmediate(MBB, MI, ScratchReg, HighOffset); 111 MI->getOperand(FIOperandNum).ChangeToRegister(BasePtr, false); 112 MI->getOperand(FIOperandNum + 2).ChangeToRegister(ScratchReg, 113 false, false, true); 114 } else { 115 // Load the anchor address into a scratch register. 116 unsigned LAOpcode = TII.getOpcodeForOffset(SystemZ::LA, HighOffset); 117 if (LAOpcode) 118 BuildMI(MBB, MI, DL, TII.get(LAOpcode),ScratchReg) 119 .addReg(BasePtr).addImm(HighOffset).addReg(0); 120 else { 121 // Load the high offset into the scratch register and use it as 122 // an index. 123 TII.loadImmediate(MBB, MI, ScratchReg, HighOffset); 124 BuildMI(MBB, MI, DL, TII.get(SystemZ::AGR),ScratchReg) 125 .addReg(ScratchReg, RegState::Kill).addReg(BasePtr); 126 } 127 128 // Use the scratch register as the base. It then dies here. 129 MI->getOperand(FIOperandNum).ChangeToRegister(ScratchReg, 130 false, false, true); 131 } 132 } 133 MI->setDesc(TII.get(OpcodeForOffset)); 134 MI->getOperand(FIOperandNum + 1).ChangeToImmediate(Offset); 135} 136 137unsigned 138SystemZRegisterInfo::getFrameRegister(const MachineFunction &MF) const { 139 const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering(); 140 return TFI->hasFP(MF) ? SystemZ::R11D : SystemZ::R15D; 141} 142