//===-- PPC32ISelLowering.cpp - PPC32 DAG Lowering Implementation ---------===// // // The LLVM Compiler Infrastructure // // This file was developed by Chris Lattner and is distributed under // the University of Illinois Open Source License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // This file implements the PPC32ISelLowering class. // //===----------------------------------------------------------------------===// #include "PPC32ISelLowering.h" #include "PPC32TargetMachine.h" #include "llvm/CodeGen/MachineFrameInfo.h" #include "llvm/CodeGen/MachineFunction.h" #include "llvm/CodeGen/MachineInstrBuilder.h" #include "llvm/CodeGen/SelectionDAG.h" #include "llvm/Constants.h" #include "llvm/Function.h" using namespace llvm; PPC32TargetLowering::PPC32TargetLowering(TargetMachine &TM) : TargetLowering(TM) { // Fold away setcc operations if possible. setSetCCIsExpensive(); // Set up the register classes. addRegisterClass(MVT::i32, PPC32::GPRCRegisterClass); addRegisterClass(MVT::f32, PPC32::FPRCRegisterClass); addRegisterClass(MVT::f64, PPC32::FPRCRegisterClass); // PowerPC has no intrinsics for these particular operations setOperationAction(ISD::MEMMOVE, MVT::Other, Expand); setOperationAction(ISD::MEMSET, MVT::Other, Expand); setOperationAction(ISD::MEMCPY, MVT::Other, Expand); // PowerPC has an i16 but no i8 (or i1) SEXTLOAD setOperationAction(ISD::SEXTLOAD, MVT::i1, Expand); setOperationAction(ISD::SEXTLOAD, MVT::i8, Expand); // PowerPC has no SREM/UREM instructions setOperationAction(ISD::SREM, MVT::i32, Expand); setOperationAction(ISD::UREM, MVT::i32, Expand); // We don't support sin/cos/sqrt/fmod setOperationAction(ISD::FSIN , MVT::f64, Expand); setOperationAction(ISD::FCOS , MVT::f64, Expand); setOperationAction(ISD::SREM , MVT::f64, Expand); setOperationAction(ISD::FSIN , MVT::f32, Expand); setOperationAction(ISD::FCOS , MVT::f32, Expand); setOperationAction(ISD::SREM , MVT::f32, Expand); // If we're enabling GP optimizations, use hardware square root if (!TM.getSubtarget().isGigaProcessor()) { setOperationAction(ISD::FSQRT, MVT::f64, Expand); setOperationAction(ISD::FSQRT, MVT::f32, Expand); } // PowerPC does not have CTPOP or CTTZ setOperationAction(ISD::CTPOP, MVT::i32 , Expand); setOperationAction(ISD::CTTZ , MVT::i32 , Expand); // PowerPC does not have Select setOperationAction(ISD::SELECT, MVT::i32, Expand); setOperationAction(ISD::SELECT, MVT::f32, Expand); setOperationAction(ISD::SELECT, MVT::f64, Expand); // PowerPC wants to turn select_cc of FP into fsel when possible. setOperationAction(ISD::SELECT_CC, MVT::f32, Custom); setOperationAction(ISD::SELECT_CC, MVT::f64, Custom); // PowerPC does not have BRCOND* which requires SetCC setOperationAction(ISD::BRCOND, MVT::Other, Expand); setOperationAction(ISD::BRCONDTWOWAY, MVT::Other, Expand); // PowerPC does not have FP_TO_UINT setOperationAction(ISD::FP_TO_UINT, MVT::i32, Expand); // PowerPC does not have [U|S]INT_TO_FP setOperationAction(ISD::SINT_TO_FP, MVT::i32, Expand); setOperationAction(ISD::UINT_TO_FP, MVT::i32, Expand); setSetCCResultContents(ZeroOrOneSetCCResult); computeRegisterProperties(); } /// isFloatingPointZero - Return true if this is 0.0 or -0.0. static bool isFloatingPointZero(SDOperand Op) { if (ConstantFPSDNode *CFP = dyn_cast(Op)) return CFP->isExactlyValue(-0.0) || CFP->isExactlyValue(0.0); else if (Op.getOpcode() == ISD::EXTLOAD || Op.getOpcode() == ISD::LOAD) { // Maybe this has already been legalized into the constant pool? if (ConstantPoolSDNode *CP = dyn_cast(Op.getOperand(1))) if (ConstantFP *CFP = dyn_cast(CP->get())) return CFP->isExactlyValue(-0.0) || CFP->isExactlyValue(0.0); } return false; } /// LowerOperation - Provide custom lowering hooks for some operations. /// SDOperand PPC32TargetLowering::LowerOperation(SDOperand Op, SelectionDAG &DAG) { switch (Op.getOpcode()) { default: assert(0 && "Wasn't expecting to be able to lower this!"); case ISD::SELECT_CC: // Turn FP only select_cc's into fsel instructions. if (MVT::isFloatingPoint(Op.getOperand(0).getValueType()) && MVT::isFloatingPoint(Op.getOperand(2).getValueType())) { ISD::CondCode CC = cast(Op.getOperand(4))->get(); MVT::ValueType ResVT = Op.getValueType(); MVT::ValueType CmpVT = Op.getOperand(0).getValueType(); SDOperand LHS = Op.getOperand(0), RHS = Op.getOperand(1); SDOperand TV = Op.getOperand(2), FV = Op.getOperand(3); // If the RHS of the comparison is a 0.0, we don't need to do the // subtraction at all. if (isFloatingPointZero(RHS)) switch (CC) { default: assert(0 && "Invalid FSEL condition"); abort(); case ISD::SETULT: case ISD::SETLT: std::swap(TV, FV); // fsel is natively setge, swap operands for setlt case ISD::SETUGE: case ISD::SETGE: return DAG.getNode(PPCISD::FSEL, ResVT, LHS, TV, FV); case ISD::SETUGT: case ISD::SETGT: std::swap(TV, FV); // fsel is natively setge, swap operands for setlt case ISD::SETULE: case ISD::SETLE: return DAG.getNode(PPCISD::FSEL, ResVT, DAG.getNode(ISD::FNEG, ResVT, LHS), TV, FV); } switch (CC) { default: assert(0 && "Invalid FSEL condition"); abort(); case ISD::SETULT: case ISD::SETLT: return DAG.getNode(PPCISD::FSEL, ResVT, DAG.getNode(ISD::SUB, CmpVT, LHS, RHS), FV, TV); case ISD::SETUGE: case ISD::SETGE: return DAG.getNode(PPCISD::FSEL, ResVT, DAG.getNode(ISD::SUB, CmpVT, LHS, RHS), TV, FV); case ISD::SETUGT: case ISD::SETGT: return DAG.getNode(PPCISD::FSEL, ResVT, DAG.getNode(ISD::SUB, CmpVT, RHS, LHS), FV, TV); case ISD::SETULE: case ISD::SETLE: return DAG.getNode(PPCISD::FSEL, ResVT, DAG.getNode(ISD::SUB, CmpVT, RHS, LHS), TV, FV); } } break; } return SDOperand(); } std::vector PPC32TargetLowering::LowerArguments(Function &F, SelectionDAG &DAG) { // // add beautiful description of PPC stack frame format, or at least some docs // MachineFunction &MF = DAG.getMachineFunction(); MachineFrameInfo *MFI = MF.getFrameInfo(); MachineBasicBlock& BB = MF.front(); std::vector ArgValues; // Due to the rather complicated nature of the PowerPC ABI, rather than a // fixed size array of physical args, for the sake of simplicity let the STL // handle tracking them for us. std::vector argVR, argPR, argOp; unsigned ArgOffset = 24; unsigned GPR_remaining = 8; unsigned FPR_remaining = 13; unsigned GPR_idx = 0, FPR_idx = 0; static const unsigned GPR[] = { PPC::R3, PPC::R4, PPC::R5, PPC::R6, PPC::R7, PPC::R8, PPC::R9, PPC::R10, }; static const unsigned FPR[] = { PPC::F1, PPC::F2, PPC::F3, PPC::F4, PPC::F5, PPC::F6, PPC::F7, PPC::F8, PPC::F9, PPC::F10, PPC::F11, PPC::F12, PPC::F13 }; // Add DAG nodes to load the arguments... On entry to a function on PPC, // the arguments start at offset 24, although they are likely to be passed // in registers. for (Function::arg_iterator I = F.arg_begin(), E = F.arg_end(); I != E; ++I) { SDOperand newroot, argt; unsigned ObjSize; bool needsLoad = false; bool ArgLive = !I->use_empty(); MVT::ValueType ObjectVT = getValueType(I->getType()); switch (ObjectVT) { default: assert(0 && "Unhandled argument type!"); case MVT::i1: case MVT::i8: case MVT::i16: case MVT::i32: ObjSize = 4; if (!ArgLive) break; if (GPR_remaining > 0) { MF.addLiveIn(GPR[GPR_idx]); argt = newroot = DAG.getCopyFromReg(DAG.getRoot(), GPR[GPR_idx], MVT::i32); if (ObjectVT != MVT::i32) argt = DAG.getNode(ISD::TRUNCATE, ObjectVT, newroot); } else { needsLoad = true; } break; case MVT::i64: ObjSize = 8; if (!ArgLive) break; if (GPR_remaining > 0) { SDOperand argHi, argLo; MF.addLiveIn(GPR[GPR_idx]); argHi = DAG.getCopyFromReg(DAG.getRoot(), GPR[GPR_idx], MVT::i32); // If we have two or more remaining argument registers, then both halves // of the i64 can be sourced from there. Otherwise, the lower half will // have to come off the stack. This can happen when an i64 is preceded // by 28 bytes of arguments. if (GPR_remaining > 1) { MF.addLiveIn(GPR[GPR_idx+1]); argLo = DAG.getCopyFromReg(argHi, GPR[GPR_idx+1], MVT::i32); } else { int FI = MFI->CreateFixedObject(4, ArgOffset+4); SDOperand FIN = DAG.getFrameIndex(FI, MVT::i32); argLo = DAG.getLoad(MVT::i32, DAG.getEntryNode(), FIN, DAG.getSrcValue(NULL)); } // Build the outgoing arg thingy argt = DAG.getNode(ISD::BUILD_PAIR, MVT::i64, argLo, argHi); newroot = argLo; } else { needsLoad = true; } break; case MVT::f32: case MVT::f64: ObjSize = (ObjectVT == MVT::f64) ? 8 : 4; if (!ArgLive) break; if (FPR_remaining > 0) { MF.addLiveIn(FPR[FPR_idx]); argt = newroot = DAG.getCopyFromReg(DAG.getRoot(), FPR[FPR_idx], ObjectVT); --FPR_remaining; ++FPR_idx; } else { needsLoad = true; } break; } // We need to load the argument to a virtual register if we determined above // that we ran out of physical registers of the appropriate type if (needsLoad) { unsigned SubregOffset = 0; if (ObjectVT == MVT::i8 || ObjectVT == MVT::i1) SubregOffset = 3; if (ObjectVT == MVT::i16) SubregOffset = 2; int FI = MFI->CreateFixedObject(ObjSize, ArgOffset); SDOperand FIN = DAG.getFrameIndex(FI, MVT::i32); FIN = DAG.getNode(ISD::ADD, MVT::i32, FIN, DAG.getConstant(SubregOffset, MVT::i32)); argt = newroot = DAG.getLoad(ObjectVT, DAG.getEntryNode(), FIN, DAG.getSrcValue(NULL)); } // Every 4 bytes of argument space consumes one of the GPRs available for // argument passing. if (GPR_remaining > 0) { unsigned delta = (GPR_remaining > 1 && ObjSize == 8) ? 2 : 1; GPR_remaining -= delta; GPR_idx += delta; } ArgOffset += ObjSize; if (newroot.Val) DAG.setRoot(newroot.getValue(1)); ArgValues.push_back(argt); } // If the function takes variable number of arguments, make a frame index for // the start of the first vararg value... for expansion of llvm.va_start. if (F.isVarArg()) { VarArgsFrameIndex = MFI->CreateFixedObject(4, ArgOffset); SDOperand FIN = DAG.getFrameIndex(VarArgsFrameIndex, MVT::i32); // If this function is vararg, store any remaining integer argument regs // to their spots on the stack so that they may be loaded by deferencing the // result of va_next. std::vector MemOps; for (; GPR_remaining > 0; --GPR_remaining, ++GPR_idx) { MF.addLiveIn(GPR[GPR_idx]); SDOperand Val = DAG.getCopyFromReg(DAG.getRoot(), GPR[GPR_idx], MVT::i32); SDOperand Store = DAG.getNode(ISD::STORE, MVT::Other, Val.getValue(1), Val, FIN, DAG.getSrcValue(NULL)); MemOps.push_back(Store); // Increment the address by four for the next argument to store SDOperand PtrOff = DAG.getConstant(4, getPointerTy()); FIN = DAG.getNode(ISD::ADD, MVT::i32, FIN, PtrOff); } DAG.setRoot(DAG.getNode(ISD::TokenFactor, MVT::Other, MemOps)); } // Finally, inform the code generator which regs we return values in. switch (getValueType(F.getReturnType())) { default: assert(0 && "Unknown type!"); case MVT::isVoid: break; case MVT::i1: case MVT::i8: case MVT::i16: case MVT::i32: MF.addLiveOut(PPC::R3); break; case MVT::i64: MF.addLiveOut(PPC::R3); MF.addLiveOut(PPC::R4); break; case MVT::f32: case MVT::f64: MF.addLiveOut(PPC::F1); break; } return ArgValues; } std::pair PPC32TargetLowering::LowerCallTo(SDOperand Chain, const Type *RetTy, bool isVarArg, unsigned CallingConv, bool isTailCall, SDOperand Callee, ArgListTy &Args, SelectionDAG &DAG) { // args_to_use will accumulate outgoing args for the ISD::CALL case in // SelectExpr to use to put the arguments in the appropriate registers. std::vector args_to_use; // Count how many bytes are to be pushed on the stack, including the linkage // area, and parameter passing area. unsigned NumBytes = 24; if (Args.empty()) { Chain = DAG.getNode(ISD::CALLSEQ_START, MVT::Other, Chain, DAG.getConstant(NumBytes, getPointerTy())); } else { for (unsigned i = 0, e = Args.size(); i != e; ++i) switch (getValueType(Args[i].second)) { default: assert(0 && "Unknown value type!"); case MVT::i1: case MVT::i8: case MVT::i16: case MVT::i32: case MVT::f32: NumBytes += 4; break; case MVT::i64: case MVT::f64: NumBytes += 8; break; } // Just to be safe, we'll always reserve the full 24 bytes of linkage area // plus 32 bytes of argument space in case any called code gets funky on us. // (Required by ABI to support var arg) if (NumBytes < 56) NumBytes = 56; // Adjust the stack pointer for the new arguments... // These operations are automatically eliminated by the prolog/epilog pass Chain = DAG.getNode(ISD::CALLSEQ_START, MVT::Other, Chain, DAG.getConstant(NumBytes, getPointerTy())); // Set up a copy of the stack pointer for use loading and storing any // arguments that may not fit in the registers available for argument // passing. SDOperand StackPtr = DAG.getCopyFromReg(DAG.getEntryNode(), PPC::R1, MVT::i32); // Figure out which arguments are going to go in registers, and which in // memory. Also, if this is a vararg function, floating point operations // must be stored to our stack, and loaded into integer regs as well, if // any integer regs are available for argument passing. unsigned ArgOffset = 24; unsigned GPR_remaining = 8; unsigned FPR_remaining = 13; std::vector MemOps; for (unsigned i = 0, e = Args.size(); i != e; ++i) { // PtrOff will be used to store the current argument to the stack if a // register cannot be found for it. SDOperand PtrOff = DAG.getConstant(ArgOffset, getPointerTy()); PtrOff = DAG.getNode(ISD::ADD, MVT::i32, StackPtr, PtrOff); MVT::ValueType ArgVT = getValueType(Args[i].second); switch (ArgVT) { default: assert(0 && "Unexpected ValueType for argument!"); case MVT::i1: case MVT::i8: case MVT::i16: // Promote the integer to 32 bits. If the input type is signed use a // sign extend, otherwise use a zero extend. if (Args[i].second->isSigned()) Args[i].first =DAG.getNode(ISD::SIGN_EXTEND, MVT::i32, Args[i].first); else Args[i].first =DAG.getNode(ISD::ZERO_EXTEND, MVT::i32, Args[i].first); // FALL THROUGH case MVT::i32: if (GPR_remaining > 0) { args_to_use.push_back(Args[i].first); --GPR_remaining; } else { MemOps.push_back(DAG.getNode(ISD::STORE, MVT::Other, Chain, Args[i].first, PtrOff, DAG.getSrcValue(NULL))); } ArgOffset += 4; break; case MVT::i64: // If we have one free GPR left, we can place the upper half of the i64 // in it, and store the other half to the stack. If we have two or more // free GPRs, then we can pass both halves of the i64 in registers. if (GPR_remaining > 0) { SDOperand Hi = DAG.getNode(ISD::EXTRACT_ELEMENT, MVT::i32, Args[i].first, DAG.getConstant(1, MVT::i32)); SDOperand Lo = DAG.getNode(ISD::EXTRACT_ELEMENT, MVT::i32, Args[i].first, DAG.getConstant(0, MVT::i32)); args_to_use.push_back(Hi); --GPR_remaining; if (GPR_remaining > 0) { args_to_use.push_back(Lo); --GPR_remaining; } else { SDOperand ConstFour = DAG.getConstant(4, getPointerTy()); PtrOff = DAG.getNode(ISD::ADD, MVT::i32, PtrOff, ConstFour); MemOps.push_back(DAG.getNode(ISD::STORE, MVT::Other, Chain, Lo, PtrOff, DAG.getSrcValue(NULL))); } } else { MemOps.push_back(DAG.getNode(ISD::STORE, MVT::Other, Chain, Args[i].first, PtrOff, DAG.getSrcValue(NULL))); } ArgOffset += 8; break; case MVT::f32: case MVT::f64: if (FPR_remaining > 0) { args_to_use.push_back(Args[i].first); --FPR_remaining; if (isVarArg) { SDOperand Store = DAG.getNode(ISD::STORE, MVT::Other, Chain, Args[i].first, PtrOff, DAG.getSrcValue(NULL)); MemOps.push_back(Store); // Float varargs are always shadowed in available integer registers if (GPR_remaining > 0) { SDOperand Load = DAG.getLoad(MVT::i32, Store, PtrOff, DAG.getSrcValue(NULL)); MemOps.push_back(Load); args_to_use.push_back(Load); --GPR_remaining; } if (GPR_remaining > 0 && MVT::f64 == ArgVT) { SDOperand ConstFour = DAG.getConstant(4, getPointerTy()); PtrOff = DAG.getNode(ISD::ADD, MVT::i32, PtrOff, ConstFour); SDOperand Load = DAG.getLoad(MVT::i32, Store, PtrOff, DAG.getSrcValue(NULL)); MemOps.push_back(Load); args_to_use.push_back(Load); --GPR_remaining; } } else { // If we have any FPRs remaining, we may also have GPRs remaining. // Args passed in FPRs consume either 1 (f32) or 2 (f64) available // GPRs. if (GPR_remaining > 0) { args_to_use.push_back(DAG.getNode(ISD::UNDEF, MVT::i32)); --GPR_remaining; } if (GPR_remaining > 0 && MVT::f64 == ArgVT) { args_to_use.push_back(DAG.getNode(ISD::UNDEF, MVT::i32)); --GPR_remaining; } } } else { MemOps.push_back(DAG.getNode(ISD::STORE, MVT::Other, Chain, Args[i].first, PtrOff, DAG.getSrcValue(NULL))); } ArgOffset += (ArgVT == MVT::f32) ? 4 : 8; break; } } if (!MemOps.empty()) Chain = DAG.getNode(ISD::TokenFactor, MVT::Other, MemOps); } std::vector RetVals; MVT::ValueType RetTyVT = getValueType(RetTy); if (RetTyVT != MVT::isVoid) RetVals.push_back(RetTyVT); RetVals.push_back(MVT::Other); SDOperand TheCall = SDOperand(DAG.getCall(RetVals, Chain, Callee, args_to_use), 0); Chain = TheCall.getValue(RetTyVT != MVT::isVoid); Chain = DAG.getNode(ISD::CALLSEQ_END, MVT::Other, Chain, DAG.getConstant(NumBytes, getPointerTy())); return std::make_pair(TheCall, Chain); } SDOperand PPC32TargetLowering::LowerVAStart(SDOperand Chain, SDOperand VAListP, Value *VAListV, SelectionDAG &DAG) { // vastart just stores the address of the VarArgsFrameIndex slot into the // memory location argument. SDOperand FR = DAG.getFrameIndex(VarArgsFrameIndex, MVT::i32); return DAG.getNode(ISD::STORE, MVT::Other, Chain, FR, VAListP, DAG.getSrcValue(VAListV)); } std::pair PPC32TargetLowering::LowerVAArg(SDOperand Chain, SDOperand VAListP, Value *VAListV, const Type *ArgTy, SelectionDAG &DAG) { MVT::ValueType ArgVT = getValueType(ArgTy); SDOperand VAList = DAG.getLoad(MVT::i32, Chain, VAListP, DAG.getSrcValue(VAListV)); SDOperand Result = DAG.getLoad(ArgVT, Chain, VAList, DAG.getSrcValue(NULL)); unsigned Amt; if (ArgVT == MVT::i32 || ArgVT == MVT::f32) Amt = 4; else { assert((ArgVT == MVT::i64 || ArgVT == MVT::f64) && "Other types should have been promoted for varargs!"); Amt = 8; } VAList = DAG.getNode(ISD::ADD, VAList.getValueType(), VAList, DAG.getConstant(Amt, VAList.getValueType())); Chain = DAG.getNode(ISD::STORE, MVT::Other, Chain, VAList, VAListP, DAG.getSrcValue(VAListV)); return std::make_pair(Result, Chain); } std::pair PPC32TargetLowering:: LowerFrameReturnAddress(bool isFrameAddress, SDOperand Chain, unsigned Depth, SelectionDAG &DAG) { assert(0 && "LowerFrameReturnAddress unimplemented"); abort(); } MachineBasicBlock * PPC32TargetLowering::InsertAtEndOfBasicBlock(MachineInstr *MI, MachineBasicBlock *BB) { assert((MI->getOpcode() == PPC::SELECT_CC_Int || MI->getOpcode() == PPC::SELECT_CC_FP) && "Unexpected instr type to insert"); // 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(); ilist::iterator It = BB; ++It; // thisMBB: // ... // TrueVal = ... // cmpTY ccX, r1, r2 // bCC copy1MBB // fallthrough --> copy0MBB MachineBasicBlock *thisMBB = BB; MachineBasicBlock *copy0MBB = new MachineBasicBlock(LLVM_BB); MachineBasicBlock *sinkMBB = new MachineBasicBlock(LLVM_BB); BuildMI(BB, MI->getOperand(4).getImmedValue(), 2) .addReg(MI->getOperand(1).getReg()).addMBB(sinkMBB); MachineFunction *F = BB->getParent(); F->getBasicBlockList().insert(It, copy0MBB); F->getBasicBlockList().insert(It, sinkMBB); // Update machine-CFG edges 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, PPC::PHI, 4, MI->getOperand(0).getReg()) .addReg(MI->getOperand(3).getReg()).addMBB(copy0MBB) .addReg(MI->getOperand(2).getReg()).addMBB(thisMBB); delete MI; // The pseudo instruction is gone now. return BB; }