1 //====- SparcFrameLowering.cpp - Sparc Frame Information -------*- C++ -*-====// 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 // This file contains the Sparc implementation of TargetFrameLowering class. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "SparcFrameLowering.h" 15 #include "SparcInstrInfo.h" 16 #include "SparcMachineFunctionInfo.h" 17 #include "llvm/Function.h" 18 #include "llvm/CodeGen/MachineFrameInfo.h" 19 #include "llvm/CodeGen/MachineFunction.h" 20 #include "llvm/CodeGen/MachineInstrBuilder.h" 21 #include "llvm/CodeGen/MachineModuleInfo.h" 22 #include "llvm/CodeGen/MachineRegisterInfo.h" 23 #include "llvm/Target/TargetData.h" 24 #include "llvm/Target/TargetOptions.h" 25 #include "llvm/Support/CommandLine.h" 26 27 using namespace llvm; 28 29 void SparcFrameLowering::emitPrologue(MachineFunction &MF) const { 30 MachineBasicBlock &MBB = MF.front(); 31 MachineFrameInfo *MFI = MF.getFrameInfo(); 32 const SparcInstrInfo &TII = 33 *static_cast<const SparcInstrInfo*>(MF.getTarget().getInstrInfo()); 34 MachineBasicBlock::iterator MBBI = MBB.begin(); 35 DebugLoc dl = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc(); 36 37 // Get the number of bytes to allocate from the FrameInfo 38 int NumBytes = (int) MFI->getStackSize(); 39 40 // Emit the correct save instruction based on the number of bytes in 41 // the frame. Minimum stack frame size according to V8 ABI is: 42 // 16 words for register window spill 43 // 1 word for address of returned aggregate-value 44 // + 6 words for passing parameters on the stack 45 // ---------- 46 // 23 words * 4 bytes per word = 92 bytes 47 NumBytes += 92; 48 49 // Round up to next doubleword boundary -- a double-word boundary 50 // is required by the ABI. 51 NumBytes = (NumBytes + 7) & ~7; 52 NumBytes = -NumBytes; 53 54 if (NumBytes >= -4096) { 55 BuildMI(MBB, MBBI, dl, TII.get(SP::SAVEri), SP::O6) 56 .addReg(SP::O6).addImm(NumBytes); 57 } else { 58 // Emit this the hard way. This clobbers G1 which we always know is 59 // available here. 60 unsigned OffHi = (unsigned)NumBytes >> 10U; 61 BuildMI(MBB, MBBI, dl, TII.get(SP::SETHIi), SP::G1).addImm(OffHi); 62 // Emit G1 = G1 + I6 63 BuildMI(MBB, MBBI, dl, TII.get(SP::ORri), SP::G1) 64 .addReg(SP::G1).addImm(NumBytes & ((1 << 10)-1)); 65 BuildMI(MBB, MBBI, dl, TII.get(SP::SAVErr), SP::O6) 66 .addReg(SP::O6).addReg(SP::G1); 67 } 68 } 69 70 void SparcFrameLowering::emitEpilogue(MachineFunction &MF, 71 MachineBasicBlock &MBB) const { 72 MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr(); 73 const SparcInstrInfo &TII = 74 *static_cast<const SparcInstrInfo*>(MF.getTarget().getInstrInfo()); 75 DebugLoc dl = MBBI->getDebugLoc(); 76 assert(MBBI->getOpcode() == SP::RETL && 77 "Can only put epilog before 'retl' instruction!"); 78 BuildMI(MBB, MBBI, dl, TII.get(SP::RESTORErr), SP::G0).addReg(SP::G0) 79 .addReg(SP::G0); 80 } 81
