//===-- MipsISelLowering.cpp - Mips DAG Lowering Implementation -----------===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // This file defines the interfaces that Mips uses to lower LLVM code into a // selection DAG. // //===----------------------------------------------------------------------===// #define DEBUG_TYPE "mips-lower" #include "MipsISelLowering.h" #include "MipsMachineFunction.h" #include "MipsTargetMachine.h" #include "MipsSubtarget.h" #include "llvm/DerivedTypes.h" #include "llvm/Function.h" #include "llvm/GlobalVariable.h" #include "llvm/Intrinsics.h" #include "llvm/CallingConv.h" #include "llvm/CodeGen/CallingConvLower.h" #include "llvm/CodeGen/MachineFrameInfo.h" #include "llvm/CodeGen/MachineFunction.h" #include "llvm/CodeGen/MachineInstrBuilder.h" #include "llvm/CodeGen/MachineRegisterInfo.h" #include "llvm/CodeGen/SelectionDAGISel.h" #include "llvm/CodeGen/ValueTypes.h" #include "llvm/Support/Debug.h" using namespace llvm; const char *MipsTargetLowering:: getTargetNodeName(unsigned Opcode) const { switch (Opcode) { case MipsISD::JmpLink : return "MipsISD::JmpLink"; case MipsISD::Hi : return "MipsISD::Hi"; case MipsISD::Lo : return "MipsISD::Lo"; case MipsISD::GPRel : return "MipsISD::GPRel"; case MipsISD::Ret : return "MipsISD::Ret"; case MipsISD::CMov : return "MipsISD::CMov"; case MipsISD::SelectCC : return "MipsISD::SelectCC"; case MipsISD::FPSelectCC : return "MipsISD::FPSelectCC"; case MipsISD::FPBrcond : return "MipsISD::FPBrcond"; case MipsISD::FPCmp : return "MipsISD::FPCmp"; default : return NULL; } } MipsTargetLowering:: MipsTargetLowering(MipsTargetMachine &TM): TargetLowering(TM) { Subtarget = &TM.getSubtarget(); // Mips does not have i1 type, so use i32 for // setcc operations results (slt, sgt, ...). setBooleanContents(ZeroOrOneBooleanContent); // JumpTable targets must use GOT when using PIC_ setUsesGlobalOffsetTable(true); // Set up the register classes addRegisterClass(MVT::i32, Mips::CPURegsRegisterClass); addRegisterClass(MVT::f32, Mips::FGR32RegisterClass); // When dealing with single precision only, use libcalls if (!Subtarget->isSingleFloat()) if (!Subtarget->isFP64bit()) addRegisterClass(MVT::f64, Mips::AFGR64RegisterClass); // Legal fp constants addLegalFPImmediate(APFloat(+0.0f)); // Load extented operations for i1 types must be promoted setLoadExtAction(ISD::EXTLOAD, MVT::i1, Promote); setLoadExtAction(ISD::ZEXTLOAD, MVT::i1, Promote); setLoadExtAction(ISD::SEXTLOAD, MVT::i1, Promote); // Used by legalize types to correctly generate the setcc result. // Without this, every float setcc comes with a AND/OR with the result, // we don't want this, since the fpcmp result goes to a flag register, // which is used implicitly by brcond and select operations. AddPromotedToType(ISD::SETCC, MVT::i1, MVT::i32); // Mips Custom Operations setOperationAction(ISD::GlobalAddress, MVT::i32, Custom); setOperationAction(ISD::GlobalTLSAddress, MVT::i32, Custom); setOperationAction(ISD::RET, MVT::Other, Custom); setOperationAction(ISD::JumpTable, MVT::i32, Custom); setOperationAction(ISD::ConstantPool, MVT::i32, Custom); setOperationAction(ISD::SELECT, MVT::f32, Custom); setOperationAction(ISD::SELECT, MVT::i32, Custom); setOperationAction(ISD::SETCC, MVT::f32, Custom); setOperationAction(ISD::BRCOND, MVT::Other, Custom); setOperationAction(ISD::DYNAMIC_STACKALLOC, MVT::i32, Custom); // We custom lower AND/OR to handle the case where the DAG contain 'ands/ors' // with operands comming from setcc fp comparions. This is necessary since // the result from these setcc are in a flag registers (FCR31). setOperationAction(ISD::AND, MVT::i32, Custom); setOperationAction(ISD::OR, MVT::i32, Custom); // Operations not directly supported by Mips. setOperationAction(ISD::BR_JT, MVT::Other, Expand); setOperationAction(ISD::BR_CC, MVT::Other, Expand); setOperationAction(ISD::SELECT_CC, MVT::Other, Expand); setOperationAction(ISD::UINT_TO_FP, MVT::i32, Expand); setOperationAction(ISD::FP_TO_UINT, MVT::i32, Expand); setOperationAction(ISD::SIGN_EXTEND_INREG, MVT::i1, Expand); setOperationAction(ISD::CTPOP, MVT::i32, Expand); setOperationAction(ISD::CTTZ, MVT::i32, Expand); setOperationAction(ISD::ROTL, MVT::i32, Expand); setOperationAction(ISD::SHL_PARTS, MVT::i32, Expand); setOperationAction(ISD::SRA_PARTS, MVT::i32, Expand); setOperationAction(ISD::SRL_PARTS, MVT::i32, Expand); setOperationAction(ISD::FCOPYSIGN, MVT::f32, Expand); // We don't have line number support yet. setOperationAction(ISD::DBG_STOPPOINT, MVT::Other, Expand); setOperationAction(ISD::DEBUG_LOC, MVT::Other, Expand); setOperationAction(ISD::DBG_LABEL, MVT::Other, Expand); setOperationAction(ISD::EH_LABEL, MVT::Other, Expand); // Use the default for now setOperationAction(ISD::STACKSAVE, MVT::Other, Expand); setOperationAction(ISD::STACKRESTORE, MVT::Other, Expand); setOperationAction(ISD::MEMBARRIER, MVT::Other, Expand); if (Subtarget->isSingleFloat()) setOperationAction(ISD::SELECT_CC, MVT::f64, Expand); if (!Subtarget->hasSEInReg()) { setOperationAction(ISD::SIGN_EXTEND_INREG, MVT::i8, Expand); setOperationAction(ISD::SIGN_EXTEND_INREG, MVT::i16, Expand); } if (!Subtarget->hasBitCount()) setOperationAction(ISD::CTLZ, MVT::i32, Expand); if (!Subtarget->hasSwap()) setOperationAction(ISD::BSWAP, MVT::i32, Expand); setStackPointerRegisterToSaveRestore(Mips::SP); computeRegisterProperties(); } MVT MipsTargetLowering::getSetCCResultType(MVT VT) const { return MVT::i32; } SDValue MipsTargetLowering:: LowerOperation(SDValue Op, SelectionDAG &DAG) { switch (Op.getOpcode()) { case ISD::AND: return LowerANDOR(Op, DAG); case ISD::BRCOND: return LowerBRCOND(Op, DAG); case ISD::CALL: return LowerCALL(Op, DAG); case ISD::ConstantPool: return LowerConstantPool(Op, DAG); case ISD::DYNAMIC_STACKALLOC: return LowerDYNAMIC_STACKALLOC(Op, DAG); case ISD::FORMAL_ARGUMENTS: return LowerFORMAL_ARGUMENTS(Op, DAG); case ISD::GlobalAddress: return LowerGlobalAddress(Op, DAG); case ISD::GlobalTLSAddress: return LowerGlobalTLSAddress(Op, DAG); case ISD::JumpTable: return LowerJumpTable(Op, DAG); case ISD::OR: return LowerANDOR(Op, DAG); case ISD::RET: return LowerRET(Op, DAG); case ISD::SELECT: return LowerSELECT(Op, DAG); case ISD::SETCC: return LowerSETCC(Op, DAG); } return SDValue(); } //===----------------------------------------------------------------------===// // Lower helper functions //===----------------------------------------------------------------------===// // AddLiveIn - This helper function adds the specified physical register to the // MachineFunction as a live in value. It also creates a corresponding // virtual register for it. static unsigned AddLiveIn(MachineFunction &MF, unsigned PReg, TargetRegisterClass *RC) { assert(RC->contains(PReg) && "Not the correct regclass!"); unsigned VReg = MF.getRegInfo().createVirtualRegister(RC); MF.getRegInfo().addLiveIn(PReg, VReg); return VReg; } // A address must be loaded from a small section if its size is less than the // small section size threshold. Data in this section must be addressed using // gp_rel operator. bool MipsTargetLowering::IsInSmallSection(unsigned Size) { return (Size > 0 && (Size <= Subtarget->getSSectionThreshold())); } // Discover if this global address can be placed into small data/bss section. bool MipsTargetLowering::IsGlobalInSmallSection(GlobalValue *GV) { const TargetData *TD = getTargetData(); const GlobalVariable *GVA = dyn_cast(GV); if (!GVA) return false; const Type *Ty = GV->getType()->getElementType(); unsigned Size = TD->getTypePaddedSize(Ty); // if this is a internal constant string, there is a special // section for it, but not in small data/bss. if (GVA->hasInitializer() && GV->hasLocalLinkage()) { Constant *C = GVA->getInitializer(); const ConstantArray *CVA = dyn_cast(C); if (CVA && CVA->isCString()) return false; } return IsInSmallSection(Size); } // Get fp branch code (not opcode) from condition code. static Mips::FPBranchCode GetFPBranchCodeFromCond(Mips::CondCode CC) { if (CC >= Mips::FCOND_F && CC <= Mips::FCOND_NGT) return Mips::BRANCH_T; if (CC >= Mips::FCOND_T && CC <= Mips::FCOND_GT) return Mips::BRANCH_F; return Mips::BRANCH_INVALID; } static unsigned FPBranchCodeToOpc(Mips::FPBranchCode BC) { switch(BC) { default: assert(0 && "Unknown branch code"); case Mips::BRANCH_T : return Mips::BC1T; case Mips::BRANCH_F : return Mips::BC1F; case Mips::BRANCH_TL : return Mips::BC1TL; case Mips::BRANCH_FL : return Mips::BC1FL; } } static Mips::CondCode FPCondCCodeToFCC(ISD::CondCode CC) { switch (CC) { default: assert(0 && "Unknown fp condition code!"); case ISD::SETEQ: case ISD::SETOEQ: return Mips::FCOND_EQ; case ISD::SETUNE: return Mips::FCOND_OGL; case ISD::SETLT: case ISD::SETOLT: return Mips::FCOND_OLT; case ISD::SETGT: case ISD::SETOGT: return Mips::FCOND_OGT; case ISD::SETLE: case ISD::SETOLE: return Mips::FCOND_OLE; case ISD::SETGE: case ISD::SETOGE: return Mips::FCOND_OGE; case ISD::SETULT: return Mips::FCOND_ULT; case ISD::SETULE: return Mips::FCOND_ULE; case ISD::SETUGT: return Mips::FCOND_UGT; case ISD::SETUGE: return Mips::FCOND_UGE; case ISD::SETUO: return Mips::FCOND_UN; case ISD::SETO: return Mips::FCOND_OR; case ISD::SETNE: case ISD::SETONE: return Mips::FCOND_NEQ; case ISD::SETUEQ: return Mips::FCOND_UEQ; } } MachineBasicBlock * MipsTargetLowering::EmitInstrWithCustomInserter(MachineInstr *MI, MachineBasicBlock *BB) const { const TargetInstrInfo *TII = getTargetMachine().getInstrInfo(); bool isFPCmp = false; DebugLoc dl = MI->getDebugLoc(); switch (MI->getOpcode()) { default: assert(false && "Unexpected instr type to insert"); case Mips::Select_FCC: case Mips::Select_FCC_S32: case Mips::Select_FCC_D32: isFPCmp = true; // FALL THROUGH case Mips::Select_CC: case Mips::Select_CC_S32: case Mips::Select_CC_D32: { // To "insert" a SELECT_CC instruction, we actually have to insert the // diamond control-flow pattern. The incoming instruction knows the // destination vreg to set, the condition code register to branch on, the // true/false values to select between, and a branch opcode to use. const BasicBlock *LLVM_BB = BB->getBasicBlock(); MachineFunction::iterator It = BB; ++It; // thisMBB: // ... // TrueVal = ... // setcc r1, r2, r3 // bNE r1, r0, copy1MBB // fallthrough --> copy0MBB MachineBasicBlock *thisMBB = BB; MachineFunction *F = BB->getParent(); MachineBasicBlock *copy0MBB = F->CreateMachineBasicBlock(LLVM_BB); MachineBasicBlock *sinkMBB = F->CreateMachineBasicBlock(LLVM_BB); // Emit the right instruction according to the type of the operands compared if (isFPCmp) { // Find the condiction code present in the setcc operation. Mips::CondCode CC = (Mips::CondCode)MI->getOperand(4).getImm(); // Get the branch opcode from the branch code. unsigned Opc = FPBranchCodeToOpc(GetFPBranchCodeFromCond(CC)); BuildMI(BB, dl, TII->get(Opc)).addMBB(sinkMBB); } else BuildMI(BB, dl, TII->get(Mips::BNE)).addReg(MI->getOperand(1).getReg()) .addReg(Mips::ZERO).addMBB(sinkMBB); F->insert(It, copy0MBB); F->insert(It, sinkMBB); // Update machine-CFG edges by first adding all successors of the current // block to the new block which will contain the Phi node for the select. for(MachineBasicBlock::succ_iterator i = BB->succ_begin(), e = BB->succ_end(); i != e; ++i) sinkMBB->addSuccessor(*i); // Next, remove all successors of the current block, and add the true // and fallthrough blocks as its successors. while(!BB->succ_empty()) BB->removeSuccessor(BB->succ_begin()); BB->addSuccessor(copy0MBB); BB->addSuccessor(sinkMBB); // copy0MBB: // %FalseValue = ... // # fallthrough to sinkMBB BB = copy0MBB; // Update machine-CFG edges BB->addSuccessor(sinkMBB); // sinkMBB: // %Result = phi [ %FalseValue, copy0MBB ], [ %TrueValue, thisMBB ] // ... BB = sinkMBB; BuildMI(BB, dl, TII->get(Mips::PHI), MI->getOperand(0).getReg()) .addReg(MI->getOperand(2).getReg()).addMBB(copy0MBB) .addReg(MI->getOperand(3).getReg()).addMBB(thisMBB); F->DeleteMachineInstr(MI); // The pseudo instruction is gone now. return BB; } } } //===----------------------------------------------------------------------===// // Misc Lower Operation implementation //===----------------------------------------------------------------------===// SDValue MipsTargetLowering:: LowerDYNAMIC_STACKALLOC(SDValue Op, SelectionDAG &DAG) { SDValue Chain = Op.getOperand(0); SDValue Size = Op.getOperand(1); DebugLoc dl = Op.getDebugLoc(); // Get a reference from Mips stack pointer SDValue StackPointer = DAG.getCopyFromReg(Chain, dl, Mips::SP, MVT::i32); // Subtract the dynamic size from the actual stack size to // obtain the new stack size. SDValue Sub = DAG.getNode(ISD::SUB, dl, MVT::i32, StackPointer, Size); // The Sub result contains the new stack start address, so it // must be placed in the stack pointer register. Chain = DAG.getCopyToReg(StackPointer.getValue(1), dl, Mips::SP, Sub); // This node always has two return values: a new stack pointer // value and a chain SDValue Ops[2] = { Sub, Chain }; return DAG.getMergeValues(Ops, 2, dl); } SDValue MipsTargetLowering:: LowerANDOR(SDValue Op, SelectionDAG &DAG) { SDValue LHS = Op.getOperand(0); SDValue RHS = Op.getOperand(1); DebugLoc dl = Op.getDebugLoc(); if (LHS.getOpcode() != MipsISD::FPCmp || RHS.getOpcode() != MipsISD::FPCmp) return Op; SDValue True = DAG.getConstant(1, MVT::i32); SDValue False = DAG.getConstant(0, MVT::i32); SDValue LSEL = DAG.getNode(MipsISD::FPSelectCC, dl, True.getValueType(), LHS, True, False, LHS.getOperand(2)); SDValue RSEL = DAG.getNode(MipsISD::FPSelectCC, dl, True.getValueType(), RHS, True, False, RHS.getOperand(2)); return DAG.getNode(Op.getOpcode(), dl, MVT::i32, LSEL, RSEL); } SDValue MipsTargetLowering:: LowerBRCOND(SDValue Op, SelectionDAG &DAG) { // The first operand is the chain, the second is the condition, the third is // the block to branch to if the condition is true. SDValue Chain = Op.getOperand(0); SDValue Dest = Op.getOperand(2); DebugLoc dl = Op.getDebugLoc(); if (Op.getOperand(1).getOpcode() != MipsISD::FPCmp) return Op; SDValue CondRes = Op.getOperand(1); SDValue CCNode = CondRes.getOperand(2); Mips::CondCode CC = (Mips::CondCode)cast(CCNode)->getZExtValue(); SDValue BrCode = DAG.getConstant(GetFPBranchCodeFromCond(CC), MVT::i32); return DAG.getNode(MipsISD::FPBrcond, dl, Op.getValueType(), Chain, BrCode, Dest, CondRes); } SDValue MipsTargetLowering:: LowerSETCC(SDValue Op, SelectionDAG &DAG) { // The operands to this are the left and right operands to compare (ops #0, // and #1) and the condition code to compare them with (op #2) as a // CondCodeSDNode. SDValue LHS = Op.getOperand(0); SDValue RHS = Op.getOperand(1); DebugLoc dl = Op.getDebugLoc(); ISD::CondCode CC = cast(Op.getOperand(2))->get(); return DAG.getNode(MipsISD::FPCmp, dl, Op.getValueType(), LHS, RHS, DAG.getConstant(FPCondCCodeToFCC(CC), MVT::i32)); } SDValue MipsTargetLowering:: LowerSELECT(SDValue Op, SelectionDAG &DAG) { SDValue Cond = Op.getOperand(0); SDValue True = Op.getOperand(1); SDValue False = Op.getOperand(2); DebugLoc dl = Op.getDebugLoc(); // if the incomming condition comes from a integer compare, the select // operation must be SelectCC or a conditional move if the subtarget // supports it. if (Cond.getOpcode() != MipsISD::FPCmp) { if (Subtarget->hasCondMov() && !True.getValueType().isFloatingPoint()) return Op; return DAG.getNode(MipsISD::SelectCC, dl, True.getValueType(), Cond, True, False); } // if the incomming condition comes from fpcmp, the select // operation must use FPSelectCC. SDValue CCNode = Cond.getOperand(2); return DAG.getNode(MipsISD::FPSelectCC, dl, True.getValueType(), Cond, True, False, CCNode); } SDValue MipsTargetLowering:: LowerGlobalAddress(SDValue Op, SelectionDAG &DAG) { // FIXME there isn't actually debug info here DebugLoc dl = Op.getDebugLoc(); GlobalValue *GV = cast(Op)->getGlobal(); SDValue GA = DAG.getTargetGlobalAddress(GV, MVT::i32); if (!Subtarget->hasABICall()) { SDVTList VTs = DAG.getVTList(MVT::i32); SDValue Ops[] = { GA }; // %gp_rel relocation if (!isa(GV) && IsGlobalInSmallSection(GV)) { SDValue GPRelNode = DAG.getNode(MipsISD::GPRel, dl, VTs, Ops, 1); SDValue GOT = DAG.getGLOBAL_OFFSET_TABLE(MVT::i32); return DAG.getNode(ISD::ADD, dl, MVT::i32, GOT, GPRelNode); } // %hi/%lo relocation SDValue HiPart = DAG.getNode(MipsISD::Hi, dl, VTs, Ops, 1); SDValue Lo = DAG.getNode(MipsISD::Lo, dl, MVT::i32, GA); return DAG.getNode(ISD::ADD, dl, MVT::i32, HiPart, Lo); } else { // Abicall relocations, TODO: make this cleaner. SDValue ResNode = DAG.getLoad(MVT::i32, dl, DAG.getEntryNode(), GA, NULL, 0); // On functions and global targets not internal linked only // a load from got/GP is necessary for PIC to work. if (!GV->hasLocalLinkage() || isa(GV)) return ResNode; SDValue Lo = DAG.getNode(MipsISD::Lo, dl, MVT::i32, GA); return DAG.getNode(ISD::ADD, dl, MVT::i32, ResNode, Lo); } assert(0 && "Dont know how to handle GlobalAddress"); return SDValue(0,0); } SDValue MipsTargetLowering:: LowerGlobalTLSAddress(SDValue Op, SelectionDAG &DAG) { assert(0 && "TLS not implemented for MIPS."); return SDValue(); // Not reached } SDValue MipsTargetLowering:: LowerJumpTable(SDValue Op, SelectionDAG &DAG) { SDValue ResNode; SDValue HiPart; // FIXME there isn't actually debug info here DebugLoc dl = Op.getDebugLoc(); MVT PtrVT = Op.getValueType(); JumpTableSDNode *JT = cast(Op); SDValue JTI = DAG.getTargetJumpTable(JT->getIndex(), PtrVT); if (getTargetMachine().getRelocationModel() != Reloc::PIC_) { SDVTList VTs = DAG.getVTList(MVT::i32); SDValue Ops[] = { JTI }; HiPart = DAG.getNode(MipsISD::Hi, dl, VTs, Ops, 1); } else // Emit Load from Global Pointer HiPart = DAG.getLoad(MVT::i32, dl, DAG.getEntryNode(), JTI, NULL, 0); SDValue Lo = DAG.getNode(MipsISD::Lo, dl, MVT::i32, JTI); ResNode = DAG.getNode(ISD::ADD, dl, MVT::i32, HiPart, Lo); return ResNode; } SDValue MipsTargetLowering:: LowerConstantPool(SDValue Op, SelectionDAG &DAG) { SDValue ResNode; ConstantPoolSDNode *N = cast(Op); Constant *C = N->getConstVal(); SDValue CP = DAG.getTargetConstantPool(C, MVT::i32, N->getAlignment()); // FIXME there isn't actually debug info here DebugLoc dl = Op.getDebugLoc(); // gp_rel relocation // FIXME: we should reference the constant pool using small data sections, // but the asm printer currently doens't support this feature without // hacking it. This feature should come soon so we can uncomment the // stuff below. //if (!Subtarget->hasABICall() && // IsInSmallSection(getTargetData()->getTypePaddedSize(C->getType()))) { // SDValue GPRelNode = DAG.getNode(MipsISD::GPRel, MVT::i32, CP); // SDValue GOT = DAG.getGLOBAL_OFFSET_TABLE(MVT::i32); // ResNode = DAG.getNode(ISD::ADD, MVT::i32, GOT, GPRelNode); //} else { // %hi/%lo relocation SDValue HiPart = DAG.getNode(MipsISD::Hi, dl, MVT::i32, CP); SDValue Lo = DAG.getNode(MipsISD::Lo, dl, MVT::i32, CP); ResNode = DAG.getNode(ISD::ADD, dl, MVT::i32, HiPart, Lo); //} return ResNode; } //===----------------------------------------------------------------------===// // Calling Convention Implementation // // The lower operations present on calling convention works on this order: // LowerCALL (virt regs --> phys regs, virt regs --> stack) // LowerFORMAL_ARGUMENTS (phys --> virt regs, stack --> virt regs) // LowerRET (virt regs --> phys regs) // LowerCALL (phys regs --> virt regs) // //===----------------------------------------------------------------------===// #include "MipsGenCallingConv.inc" //===----------------------------------------------------------------------===// // TODO: Implement a generic logic using tblgen that can support this. // Mips O32 ABI rules: // --- // i32 - Passed in A0, A1, A2, A3 and stack // f32 - Only passed in f32 registers if no int reg has been used yet to hold // an argument. Otherwise, passed in A1, A2, A3 and stack. // f64 - Only passed in two aliased f32 registers if no int reg has been used // yet to hold an argument. Otherwise, use A2, A3 and stack. If A1 is // not used, it must be shadowed. If only A3 is avaiable, shadow it and // go to stack. //===----------------------------------------------------------------------===// static bool CC_MipsO32(unsigned ValNo, MVT ValVT, MVT LocVT, CCValAssign::LocInfo LocInfo, ISD::ArgFlagsTy ArgFlags, CCState &State) { static const unsigned IntRegsSize=4, FloatRegsSize=2; static const unsigned IntRegs[] = { Mips::A0, Mips::A1, Mips::A2, Mips::A3 }; static const unsigned F32Regs[] = { Mips::F12, Mips::F14 }; static const unsigned F64Regs[] = { Mips::D6, Mips::D7 }; unsigned Reg=0; unsigned UnallocIntReg = State.getFirstUnallocated(IntRegs, IntRegsSize); bool IntRegUsed = (IntRegs[UnallocIntReg] != (unsigned (Mips::A0))); // Promote i8 and i16 if (LocVT == MVT::i8 || LocVT == MVT::i16) { LocVT = MVT::i32; if (ArgFlags.isSExt()) LocInfo = CCValAssign::SExt; else if (ArgFlags.isZExt()) LocInfo = CCValAssign::ZExt; else LocInfo = CCValAssign::AExt; } if (ValVT == MVT::i32 || (ValVT == MVT::f32 && IntRegUsed)) { Reg = State.AllocateReg(IntRegs, IntRegsSize); IntRegUsed = true; LocVT = MVT::i32; } if (ValVT.isFloatingPoint() && !IntRegUsed) { if (ValVT == MVT::f32) Reg = State.AllocateReg(F32Regs, FloatRegsSize); else Reg = State.AllocateReg(F64Regs, FloatRegsSize); } if (ValVT == MVT::f64 && IntRegUsed) { if (UnallocIntReg != IntRegsSize) { // If we hit register A3 as the first not allocated, we must // mark it as allocated (shadow) and use the stack instead. if (IntRegs[UnallocIntReg] != (unsigned (Mips::A3))) Reg = Mips::A2; for (;UnallocIntReg < IntRegsSize; ++UnallocIntReg) State.AllocateReg(UnallocIntReg); } LocVT = MVT::i32; } if (!Reg) { unsigned SizeInBytes = ValVT.getSizeInBits() >> 3; unsigned Offset = State.AllocateStack(SizeInBytes, SizeInBytes); State.addLoc(CCValAssign::getMem(ValNo, ValVT, Offset, LocVT, LocInfo)); } else State.addLoc(CCValAssign::getReg(ValNo, ValVT, Reg, LocVT, LocInfo)); return false; // CC must always match } //===----------------------------------------------------------------------===// // CALL Calling Convention Implementation //===----------------------------------------------------------------------===// /// LowerCALL - functions arguments are copied from virtual regs to /// (physical regs)/(stack frame), CALLSEQ_START and CALLSEQ_END are emitted. /// TODO: isVarArg, isTailCall. SDValue MipsTargetLowering:: LowerCALL(SDValue Op, SelectionDAG &DAG) { MachineFunction &MF = DAG.getMachineFunction(); CallSDNode *TheCall = cast(Op.getNode()); SDValue Chain = TheCall->getChain(); SDValue Callee = TheCall->getCallee(); bool isVarArg = TheCall->isVarArg(); unsigned CC = TheCall->getCallingConv(); DebugLoc dl = TheCall->getDebugLoc(); MachineFrameInfo *MFI = MF.getFrameInfo(); // Analyze operands of the call, assigning locations to each operand. SmallVector ArgLocs; CCState CCInfo(CC, isVarArg, getTargetMachine(), ArgLocs); // To meet O32 ABI, Mips must always allocate 16 bytes on // the stack (even if less than 4 are used as arguments) if (Subtarget->isABI_O32()) { int VTsize = MVT(MVT::i32).getSizeInBits()/8; MFI->CreateFixedObject(VTsize, (VTsize*3)); CCInfo.AnalyzeCallOperands(TheCall, CC_MipsO32); } else CCInfo.AnalyzeCallOperands(TheCall, CC_Mips); // Get a count of how many bytes are to be pushed on the stack. unsigned NumBytes = CCInfo.getNextStackOffset(); Chain = DAG.getCALLSEQ_START(Chain, DAG.getIntPtrConstant(NumBytes, true)); // With EABI is it possible to have 16 args on registers. SmallVector, 16> RegsToPass; SmallVector MemOpChains; // First/LastArgStackLoc contains the first/last // "at stack" argument location. int LastArgStackLoc = 0; unsigned FirstStackArgLoc = (Subtarget->isABI_EABI() ? 0 : 16); // Walk the register/memloc assignments, inserting copies/loads. for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) { SDValue Arg = TheCall->getArg(i); CCValAssign &VA = ArgLocs[i]; // Promote the value if needed. switch (VA.getLocInfo()) { default: assert(0 && "Unknown loc info!"); case CCValAssign::Full: if (Subtarget->isABI_O32() && VA.isRegLoc()) { if (VA.getValVT() == MVT::f32 && VA.getLocVT() == MVT::i32) Arg = DAG.getNode(ISD::BIT_CONVERT, dl, MVT::i32, Arg); if (VA.getValVT() == MVT::f64 && VA.getLocVT() == MVT::i32) { Arg = DAG.getNode(ISD::BIT_CONVERT, dl, MVT::i64, Arg); SDValue Lo = DAG.getNode(ISD::EXTRACT_ELEMENT, dl, MVT::i32, Arg, DAG.getConstant(0, getPointerTy())); SDValue Hi = DAG.getNode(ISD::EXTRACT_ELEMENT, dl, MVT::i32, Arg, DAG.getConstant(1, getPointerTy())); RegsToPass.push_back(std::make_pair(VA.getLocReg(), Lo)); RegsToPass.push_back(std::make_pair(VA.getLocReg()+1, Hi)); continue; } } break; case CCValAssign::SExt: Arg = DAG.getNode(ISD::SIGN_EXTEND, dl, VA.getLocVT(), Arg); break; case CCValAssign::ZExt: Arg = DAG.getNode(ISD::ZERO_EXTEND, dl, VA.getLocVT(), Arg); break; case CCValAssign::AExt: Arg = DAG.getNode(ISD::ANY_EXTEND, dl, VA.getLocVT(), Arg); break; } // Arguments that can be passed on register must be kept at // RegsToPass vector if (VA.isRegLoc()) { RegsToPass.push_back(std::make_pair(VA.getLocReg(), Arg)); continue; } // Register can't get to this point... assert(VA.isMemLoc()); // Create the frame index object for this incoming parameter // This guarantees that when allocating Local Area the firsts // 16 bytes which are alwayes reserved won't be overwritten // if O32 ABI is used. For EABI the first address is zero. LastArgStackLoc = (FirstStackArgLoc + VA.getLocMemOffset()); int FI = MFI->CreateFixedObject(VA.getValVT().getSizeInBits()/8, LastArgStackLoc); SDValue PtrOff = DAG.getFrameIndex(FI,getPointerTy()); // emit ISD::STORE whichs stores the // parameter value to a stack Location MemOpChains.push_back(DAG.getStore(Chain, dl, Arg, PtrOff, NULL, 0)); } // Transform all store nodes into one single node because all store // nodes are independent of each other. if (!MemOpChains.empty()) Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, &MemOpChains[0], MemOpChains.size()); // Build a sequence of copy-to-reg nodes chained together with token // chain and flag operands which copy the outgoing args into registers. // The InFlag in necessary since all emited instructions must be // stuck together. SDValue InFlag; for (unsigned i = 0, e = RegsToPass.size(); i != e; ++i) { Chain = DAG.getCopyToReg(Chain, dl, RegsToPass[i].first, RegsToPass[i].second, InFlag); InFlag = Chain.getValue(1); } // If the callee is a GlobalAddress/ExternalSymbol node (quite common, every // direct call is) turn it into a TargetGlobalAddress/TargetExternalSymbol // node so that legalize doesn't hack it. if (GlobalAddressSDNode *G = dyn_cast(Callee)) Callee = DAG.getTargetGlobalAddress(G->getGlobal(), getPointerTy()); else if (ExternalSymbolSDNode *S = dyn_cast(Callee)) Callee = DAG.getTargetExternalSymbol(S->getSymbol(), getPointerTy()); // MipsJmpLink = #chain, #target_address, #opt_in_flags... // = Chain, Callee, Reg#1, Reg#2, ... // // Returns a chain & a flag for retval copy to use. SDVTList NodeTys = DAG.getVTList(MVT::Other, MVT::Flag); SmallVector Ops; Ops.push_back(Chain); Ops.push_back(Callee); // Add argument registers to the end of the list so that they are // known live into the call. for (unsigned i = 0, e = RegsToPass.size(); i != e; ++i) Ops.push_back(DAG.getRegister(RegsToPass[i].first, RegsToPass[i].second.getValueType())); if (InFlag.getNode()) Ops.push_back(InFlag); Chain = DAG.getNode(MipsISD::JmpLink, dl, NodeTys, &Ops[0], Ops.size()); InFlag = Chain.getValue(1); // Create the CALLSEQ_END node. Chain = DAG.getCALLSEQ_END(Chain, DAG.getIntPtrConstant(NumBytes, true), DAG.getIntPtrConstant(0, true), InFlag); InFlag = Chain.getValue(1); // Create a stack location to hold GP when PIC is used. This stack // location is used on function prologue to save GP and also after all // emited CALL's to restore GP. if (getTargetMachine().getRelocationModel() == Reloc::PIC_) { // Function can have an arbitrary number of calls, so // hold the LastArgStackLoc with the biggest offset. int FI; MipsFunctionInfo *MipsFI = MF.getInfo(); if (LastArgStackLoc >= MipsFI->getGPStackOffset()) { LastArgStackLoc = (!LastArgStackLoc) ? (16) : (LastArgStackLoc+4); // Create the frame index only once. SPOffset here can be anything // (this will be fixed on processFunctionBeforeFrameFinalized) if (MipsFI->getGPStackOffset() == -1) { FI = MFI->CreateFixedObject(4, 0); MipsFI->setGPFI(FI); } MipsFI->setGPStackOffset(LastArgStackLoc); } // Reload GP value. FI = MipsFI->getGPFI(); SDValue FIN = DAG.getFrameIndex(FI,getPointerTy()); SDValue GPLoad = DAG.getLoad(MVT::i32, dl, Chain, FIN, NULL, 0); Chain = GPLoad.getValue(1); Chain = DAG.getCopyToReg(Chain, dl, DAG.getRegister(Mips::GP, MVT::i32), GPLoad, SDValue(0,0)); InFlag = Chain.getValue(1); } // Handle result values, copying them out of physregs into vregs that we // return. return SDValue(LowerCallResult(Chain, InFlag, TheCall, CC, DAG), Op.getResNo()); } /// LowerCallResult - Lower the result values of an ISD::CALL into the /// appropriate copies out of appropriate physical registers. This assumes that /// Chain/InFlag are the input chain/flag to use, and that TheCall is the call /// being lowered. Returns a SDNode with the same number of values as the /// ISD::CALL. SDNode *MipsTargetLowering:: LowerCallResult(SDValue Chain, SDValue InFlag, CallSDNode *TheCall, unsigned CallingConv, SelectionDAG &DAG) { bool isVarArg = TheCall->isVarArg(); DebugLoc dl = TheCall->getDebugLoc(); // Assign locations to each value returned by this call. SmallVector RVLocs; CCState CCInfo(CallingConv, isVarArg, getTargetMachine(), RVLocs); CCInfo.AnalyzeCallResult(TheCall, RetCC_Mips); SmallVector ResultVals; // Copy all of the result registers out of their specified physreg. for (unsigned i = 0; i != RVLocs.size(); ++i) { Chain = DAG.getCopyFromReg(Chain, dl, RVLocs[i].getLocReg(), RVLocs[i].getValVT(), InFlag).getValue(1); InFlag = Chain.getValue(2); ResultVals.push_back(Chain.getValue(0)); } ResultVals.push_back(Chain); // Merge everything together with a MERGE_VALUES node. return DAG.getNode(ISD::MERGE_VALUES, dl, TheCall->getVTList(), &ResultVals[0], ResultVals.size()).getNode(); } //===----------------------------------------------------------------------===// // FORMAL_ARGUMENTS Calling Convention Implementation //===----------------------------------------------------------------------===// /// LowerFORMAL_ARGUMENTS - transform physical registers into /// virtual registers and generate load operations for /// arguments places on the stack. /// TODO: isVarArg SDValue MipsTargetLowering:: LowerFORMAL_ARGUMENTS(SDValue Op, SelectionDAG &DAG) { SDValue Root = Op.getOperand(0); MachineFunction &MF = DAG.getMachineFunction(); MachineFrameInfo *MFI = MF.getFrameInfo(); MipsFunctionInfo *MipsFI = MF.getInfo(); DebugLoc dl = Op.getDebugLoc(); bool isVarArg = cast(Op.getOperand(2))->getZExtValue() != 0; unsigned CC = DAG.getMachineFunction().getFunction()->getCallingConv(); unsigned StackReg = MF.getTarget().getRegisterInfo()->getFrameRegister(MF); // GP must be live into PIC and non-PIC call target. AddLiveIn(MF, Mips::GP, Mips::CPURegsRegisterClass); // Assign locations to all of the incoming arguments. SmallVector ArgLocs; CCState CCInfo(CC, isVarArg, getTargetMachine(), ArgLocs); if (Subtarget->isABI_O32()) CCInfo.AnalyzeFormalArguments(Op.getNode(), CC_MipsO32); else CCInfo.AnalyzeFormalArguments(Op.getNode(), CC_Mips); SmallVector ArgValues; SDValue StackPtr; unsigned FirstStackArgLoc = (Subtarget->isABI_EABI() ? 0 : 16); for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) { CCValAssign &VA = ArgLocs[i]; // Arguments stored on registers if (VA.isRegLoc()) { MVT RegVT = VA.getLocVT(); TargetRegisterClass *RC = 0; if (RegVT == MVT::i32) RC = Mips::CPURegsRegisterClass; else if (RegVT == MVT::f32) RC = Mips::FGR32RegisterClass; else if (RegVT == MVT::f64) { if (!Subtarget->isSingleFloat()) RC = Mips::AFGR64RegisterClass; } else assert(0 && "RegVT not supported by FORMAL_ARGUMENTS Lowering"); // Transform the arguments stored on // physical registers into virtual ones unsigned Reg = AddLiveIn(DAG.getMachineFunction(), VA.getLocReg(), RC); SDValue ArgValue = DAG.getCopyFromReg(Root, dl, Reg, RegVT); // If this is an 8 or 16-bit value, it has been passed promoted // to 32 bits. Insert an assert[sz]ext to capture this, then // truncate to the right size. if (VA.getLocInfo() != CCValAssign::Full) { unsigned Opcode = 0; if (VA.getLocInfo() == CCValAssign::SExt) Opcode = ISD::AssertSext; else if (VA.getLocInfo() == CCValAssign::ZExt) Opcode = ISD::AssertZext; if (Opcode) ArgValue = DAG.getNode(Opcode, dl, RegVT, ArgValue, DAG.getValueType(VA.getValVT())); ArgValue = DAG.getNode(ISD::TRUNCATE, dl, VA.getValVT(), ArgValue); } // Handle O32 ABI cases: i32->f32 and (i32,i32)->f64 if (Subtarget->isABI_O32()) { if (RegVT == MVT::i32 && VA.getValVT() == MVT::f32) ArgValue = DAG.getNode(ISD::BIT_CONVERT, dl, MVT::f32, ArgValue); if (RegVT == MVT::i32 && VA.getValVT() == MVT::f64) { unsigned Reg2 = AddLiveIn(DAG.getMachineFunction(), VA.getLocReg()+1, RC); SDValue ArgValue2 = DAG.getCopyFromReg(Root, dl, Reg2, RegVT); SDValue Hi = DAG.getNode(ISD::BIT_CONVERT, dl, MVT::f32, ArgValue); SDValue Lo = DAG.getNode(ISD::BIT_CONVERT, dl, MVT::f32, ArgValue2); ArgValue = DAG.getNode(ISD::BUILD_PAIR, dl, MVT::f64, Lo, Hi); } } ArgValues.push_back(ArgValue); // To meet ABI, when VARARGS are passed on registers, the registers // must have their values written to the caller stack frame. if ((isVarArg) && (Subtarget->isABI_O32())) { if (StackPtr.getNode() == 0) StackPtr = DAG.getRegister(StackReg, getPointerTy()); // The stack pointer offset is relative to the caller stack frame. // Since the real stack size is unknown here, a negative SPOffset // is used so there's a way to adjust these offsets when the stack // size get known (on EliminateFrameIndex). A dummy SPOffset is // used instead of a direct negative address (which is recorded to // be used on emitPrologue) to avoid mis-calc of the first stack // offset on PEI::calculateFrameObjectOffsets. // Arguments are always 32-bit. int FI = MFI->CreateFixedObject(4, 0); MipsFI->recordStoreVarArgsFI(FI, -(4+(i*4))); SDValue PtrOff = DAG.getFrameIndex(FI, getPointerTy()); // emit ISD::STORE whichs stores the // parameter value to a stack Location ArgValues.push_back(DAG.getStore(Root, dl, ArgValue, PtrOff, NULL, 0)); } } else { // VA.isRegLoc() // sanity check assert(VA.isMemLoc()); // The stack pointer offset is relative to the caller stack frame. // Since the real stack size is unknown here, a negative SPOffset // is used so there's a way to adjust these offsets when the stack // size get known (on EliminateFrameIndex). A dummy SPOffset is // used instead of a direct negative address (which is recorded to // be used on emitPrologue) to avoid mis-calc of the first stack // offset on PEI::calculateFrameObjectOffsets. // Arguments are always 32-bit. unsigned ArgSize = VA.getLocVT().getSizeInBits()/8; int FI = MFI->CreateFixedObject(ArgSize, 0); MipsFI->recordLoadArgsFI(FI, -(ArgSize+ (FirstStackArgLoc + VA.getLocMemOffset()))); // Create load nodes to retrieve arguments from the stack SDValue FIN = DAG.getFrameIndex(FI, getPointerTy()); ArgValues.push_back(DAG.getLoad(VA.getValVT(), dl, Root, FIN, NULL, 0)); } } // The mips ABIs for returning structs by value requires that we copy // the sret argument into $v0 for the return. Save the argument into // a virtual register so that we can access it from the return points. if (DAG.getMachineFunction().getFunction()->hasStructRetAttr()) { unsigned Reg = MipsFI->getSRetReturnReg(); if (!Reg) { Reg = MF.getRegInfo().createVirtualRegister(getRegClassFor(MVT::i32)); MipsFI->setSRetReturnReg(Reg); } SDValue Copy = DAG.getCopyToReg(DAG.getEntryNode(), dl, Reg, ArgValues[0]); Root = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, Copy, Root); } ArgValues.push_back(Root); // Return the new list of results. return DAG.getNode(ISD::MERGE_VALUES, dl, Op.getNode()->getVTList(), &ArgValues[0], ArgValues.size()).getValue(Op.getResNo()); } //===----------------------------------------------------------------------===// // Return Value Calling Convention Implementation //===----------------------------------------------------------------------===// SDValue MipsTargetLowering:: LowerRET(SDValue Op, SelectionDAG &DAG) { // CCValAssign - represent the assignment of // the return value to a location SmallVector RVLocs; unsigned CC = DAG.getMachineFunction().getFunction()->getCallingConv(); bool isVarArg = DAG.getMachineFunction().getFunction()->isVarArg(); DebugLoc dl = Op.getDebugLoc(); // CCState - Info about the registers and stack slot. CCState CCInfo(CC, isVarArg, getTargetMachine(), RVLocs); // Analize return values of ISD::RET CCInfo.AnalyzeReturn(Op.getNode(), RetCC_Mips); // If this is the first return lowered for this function, add // the regs to the liveout set for the function. if (DAG.getMachineFunction().getRegInfo().liveout_empty()) { for (unsigned i = 0; i != RVLocs.size(); ++i) if (RVLocs[i].isRegLoc()) DAG.getMachineFunction().getRegInfo().addLiveOut(RVLocs[i].getLocReg()); } // The chain is always operand #0 SDValue Chain = Op.getOperand(0); SDValue Flag; // Copy the result values into the output registers. for (unsigned i = 0; i != RVLocs.size(); ++i) { CCValAssign &VA = RVLocs[i]; assert(VA.isRegLoc() && "Can only return in registers!"); // ISD::RET => ret chain, (regnum1,val1), ... // So i*2+1 index only the regnums Chain = DAG.getCopyToReg(Chain, dl, VA.getLocReg(), Op.getOperand(i*2+1), Flag); // guarantee that all emitted copies are // stuck together, avoiding something bad Flag = Chain.getValue(1); } // The mips ABIs for returning structs by value requires that we copy // the sret argument into $v0 for the return. We saved the argument into // a virtual register in the entry block, so now we copy the value out // and into $v0. if (DAG.getMachineFunction().getFunction()->hasStructRetAttr()) { MachineFunction &MF = DAG.getMachineFunction(); MipsFunctionInfo *MipsFI = MF.getInfo(); unsigned Reg = MipsFI->getSRetReturnReg(); if (!Reg) assert(0 && "sret virtual register not created in the entry block"); SDValue Val = DAG.getCopyFromReg(Chain, dl, Reg, getPointerTy()); Chain = DAG.getCopyToReg(Chain, dl, Mips::V0, Val, Flag); Flag = Chain.getValue(1); } // Return on Mips is always a "jr $ra" if (Flag.getNode()) return DAG.getNode(MipsISD::Ret, dl, MVT::Other, Chain, DAG.getRegister(Mips::RA, MVT::i32), Flag); else // Return Void return DAG.getNode(MipsISD::Ret, dl, MVT::Other, Chain, DAG.getRegister(Mips::RA, MVT::i32)); } //===----------------------------------------------------------------------===// // Mips Inline Assembly Support //===----------------------------------------------------------------------===// /// getConstraintType - Given a constraint letter, return the type of /// constraint it is for this target. MipsTargetLowering::ConstraintType MipsTargetLowering:: getConstraintType(const std::string &Constraint) const { // Mips specific constrainy // GCC config/mips/constraints.md // // 'd' : An address register. Equivalent to r // unless generating MIPS16 code. // 'y' : Equivalent to r; retained for // backwards compatibility. // 'f' : Floating Point registers. if (Constraint.size() == 1) { switch (Constraint[0]) { default : break; case 'd': case 'y': case 'f': return C_RegisterClass; break; } } return TargetLowering::getConstraintType(Constraint); } /// getRegClassForInlineAsmConstraint - Given a constraint letter (e.g. "r"), /// return a list of registers that can be used to satisfy the constraint. /// This should only be used for C_RegisterClass constraints. std::pair MipsTargetLowering:: getRegForInlineAsmConstraint(const std::string &Constraint, MVT VT) const { if (Constraint.size() == 1) { switch (Constraint[0]) { case 'r': return std::make_pair(0U, Mips::CPURegsRegisterClass); case 'f': if (VT == MVT::f32) return std::make_pair(0U, Mips::FGR32RegisterClass); if (VT == MVT::f64) if ((!Subtarget->isSingleFloat()) && (!Subtarget->isFP64bit())) return std::make_pair(0U, Mips::AFGR64RegisterClass); } } return TargetLowering::getRegForInlineAsmConstraint(Constraint, VT); } /// Given a register class constraint, like 'r', if this corresponds directly /// to an LLVM register class, return a register of 0 and the register class /// pointer. std::vector MipsTargetLowering:: getRegClassForInlineAsmConstraint(const std::string &Constraint, MVT VT) const { if (Constraint.size() != 1) return std::vector(); switch (Constraint[0]) { default : break; case 'r': // GCC Mips Constraint Letters case 'd': case 'y': return make_vector(Mips::T0, Mips::T1, Mips::T2, Mips::T3, Mips::T4, Mips::T5, Mips::T6, Mips::T7, Mips::S0, Mips::S1, Mips::S2, Mips::S3, Mips::S4, Mips::S5, Mips::S6, Mips::S7, Mips::T8, 0); case 'f': if (VT == MVT::f32) { if (Subtarget->isSingleFloat()) return make_vector(Mips::F2, Mips::F3, Mips::F4, Mips::F5, Mips::F6, Mips::F7, Mips::F8, Mips::F9, Mips::F10, Mips::F11, Mips::F20, Mips::F21, Mips::F22, Mips::F23, Mips::F24, Mips::F25, Mips::F26, Mips::F27, Mips::F28, Mips::F29, Mips::F30, Mips::F31, 0); else return make_vector(Mips::F2, Mips::F4, Mips::F6, Mips::F8, Mips::F10, Mips::F20, Mips::F22, Mips::F24, Mips::F26, Mips::F28, Mips::F30, 0); } if (VT == MVT::f64) if ((!Subtarget->isSingleFloat()) && (!Subtarget->isFP64bit())) return make_vector(Mips::D1, Mips::D2, Mips::D3, Mips::D4, Mips::D5, Mips::D10, Mips::D11, Mips::D12, Mips::D13, Mips::D14, Mips::D15, 0); } return std::vector(); } bool MipsTargetLowering::isOffsetFoldingLegal(const GlobalAddressSDNode *GA) const { // The Mips target isn't yet aware of offsets. return false; }