| //==--- InstrEmitter.cpp - Emit MachineInstrs for the SelectionDAG class ---==// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This implements the Emit routines for the SelectionDAG class, which creates |
| // MachineInstrs based on the decisions of the SelectionDAG instruction |
| // selection. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #define DEBUG_TYPE "instr-emitter" |
| #include "InstrEmitter.h" |
| #include "SDNodeDbgValue.h" |
| #include "llvm/ADT/Statistic.h" |
| #include "llvm/CodeGen/MachineConstantPool.h" |
| #include "llvm/CodeGen/MachineFunction.h" |
| #include "llvm/CodeGen/MachineInstrBuilder.h" |
| #include "llvm/CodeGen/MachineRegisterInfo.h" |
| #include "llvm/IR/DataLayout.h" |
| #include "llvm/Support/Debug.h" |
| #include "llvm/Support/ErrorHandling.h" |
| #include "llvm/Support/MathExtras.h" |
| #include "llvm/Target/TargetInstrInfo.h" |
| #include "llvm/Target/TargetLowering.h" |
| #include "llvm/Target/TargetMachine.h" |
| using namespace llvm; |
| |
| /// MinRCSize - Smallest register class we allow when constraining virtual |
| /// registers. If satisfying all register class constraints would require |
| /// using a smaller register class, emit a COPY to a new virtual register |
| /// instead. |
| const unsigned MinRCSize = 4; |
| |
| /// CountResults - The results of target nodes have register or immediate |
| /// operands first, then an optional chain, and optional glue operands (which do |
| /// not go into the resulting MachineInstr). |
| unsigned InstrEmitter::CountResults(SDNode *Node) { |
| unsigned N = Node->getNumValues(); |
| while (N && Node->getValueType(N - 1) == MVT::Glue) |
| --N; |
| if (N && Node->getValueType(N - 1) == MVT::Other) |
| --N; // Skip over chain result. |
| return N; |
| } |
| |
| /// countOperands - The inputs to target nodes have any actual inputs first, |
| /// followed by an optional chain operand, then an optional glue operand. |
| /// Compute the number of actual operands that will go into the resulting |
| /// MachineInstr. |
| /// |
| /// Also count physreg RegisterSDNode and RegisterMaskSDNode operands preceding |
| /// the chain and glue. These operands may be implicit on the machine instr. |
| static unsigned countOperands(SDNode *Node, unsigned NumExpUses, |
| unsigned &NumImpUses) { |
| unsigned N = Node->getNumOperands(); |
| while (N && Node->getOperand(N - 1).getValueType() == MVT::Glue) |
| --N; |
| if (N && Node->getOperand(N - 1).getValueType() == MVT::Other) |
| --N; // Ignore chain if it exists. |
| |
| // Count RegisterSDNode and RegisterMaskSDNode operands for NumImpUses. |
| NumImpUses = N - NumExpUses; |
| for (unsigned I = N; I > NumExpUses; --I) { |
| if (isa<RegisterMaskSDNode>(Node->getOperand(I - 1))) |
| continue; |
| if (RegisterSDNode *RN = dyn_cast<RegisterSDNode>(Node->getOperand(I - 1))) |
| if (TargetRegisterInfo::isPhysicalRegister(RN->getReg())) |
| continue; |
| NumImpUses = N - I; |
| break; |
| } |
| |
| return N; |
| } |
| |
| /// EmitCopyFromReg - Generate machine code for an CopyFromReg node or an |
| /// implicit physical register output. |
| void InstrEmitter:: |
| EmitCopyFromReg(SDNode *Node, unsigned ResNo, bool IsClone, bool IsCloned, |
| unsigned SrcReg, DenseMap<SDValue, unsigned> &VRBaseMap) { |
| unsigned VRBase = 0; |
| if (TargetRegisterInfo::isVirtualRegister(SrcReg)) { |
| // Just use the input register directly! |
| SDValue Op(Node, ResNo); |
| if (IsClone) |
| VRBaseMap.erase(Op); |
| bool isNew = VRBaseMap.insert(std::make_pair(Op, SrcReg)).second; |
| (void)isNew; // Silence compiler warning. |
| assert(isNew && "Node emitted out of order - early"); |
| return; |
| } |
| |
| // If the node is only used by a CopyToReg and the dest reg is a vreg, use |
| // the CopyToReg'd destination register instead of creating a new vreg. |
| bool MatchReg = true; |
| const TargetRegisterClass *UseRC = NULL; |
| MVT VT = Node->getSimpleValueType(ResNo); |
| |
| // Stick to the preferred register classes for legal types. |
| if (TLI->isTypeLegal(VT)) |
| UseRC = TLI->getRegClassFor(VT); |
| |
| if (!IsClone && !IsCloned) |
| for (SDNode::use_iterator UI = Node->use_begin(), E = Node->use_end(); |
| UI != E; ++UI) { |
| SDNode *User = *UI; |
| bool Match = true; |
| if (User->getOpcode() == ISD::CopyToReg && |
| User->getOperand(2).getNode() == Node && |
| User->getOperand(2).getResNo() == ResNo) { |
| unsigned DestReg = cast<RegisterSDNode>(User->getOperand(1))->getReg(); |
| if (TargetRegisterInfo::isVirtualRegister(DestReg)) { |
| VRBase = DestReg; |
| Match = false; |
| } else if (DestReg != SrcReg) |
| Match = false; |
| } else { |
| for (unsigned i = 0, e = User->getNumOperands(); i != e; ++i) { |
| SDValue Op = User->getOperand(i); |
| if (Op.getNode() != Node || Op.getResNo() != ResNo) |
| continue; |
| MVT VT = Node->getSimpleValueType(Op.getResNo()); |
| if (VT == MVT::Other || VT == MVT::Glue) |
| continue; |
| Match = false; |
| if (User->isMachineOpcode()) { |
| const MCInstrDesc &II = TII->get(User->getMachineOpcode()); |
| const TargetRegisterClass *RC = 0; |
| if (i+II.getNumDefs() < II.getNumOperands()) { |
| RC = TRI->getAllocatableClass( |
| TII->getRegClass(II, i+II.getNumDefs(), TRI, *MF)); |
| } |
| if (!UseRC) |
| UseRC = RC; |
| else if (RC) { |
| const TargetRegisterClass *ComRC = |
| TRI->getCommonSubClass(UseRC, RC); |
| // If multiple uses expect disjoint register classes, we emit |
| // copies in AddRegisterOperand. |
| if (ComRC) |
| UseRC = ComRC; |
| } |
| } |
| } |
| } |
| MatchReg &= Match; |
| if (VRBase) |
| break; |
| } |
| |
| const TargetRegisterClass *SrcRC = 0, *DstRC = 0; |
| SrcRC = TRI->getMinimalPhysRegClass(SrcReg, VT); |
| |
| // Figure out the register class to create for the destreg. |
| if (VRBase) { |
| DstRC = MRI->getRegClass(VRBase); |
| } else if (UseRC) { |
| assert(UseRC->hasType(VT) && "Incompatible phys register def and uses!"); |
| DstRC = UseRC; |
| } else { |
| DstRC = TLI->getRegClassFor(VT); |
| } |
| |
| // If all uses are reading from the src physical register and copying the |
| // register is either impossible or very expensive, then don't create a copy. |
| if (MatchReg && SrcRC->getCopyCost() < 0) { |
| VRBase = SrcReg; |
| } else { |
| // Create the reg, emit the copy. |
| VRBase = MRI->createVirtualRegister(DstRC); |
| BuildMI(*MBB, InsertPos, Node->getDebugLoc(), TII->get(TargetOpcode::COPY), |
| VRBase).addReg(SrcReg); |
| } |
| |
| SDValue Op(Node, ResNo); |
| if (IsClone) |
| VRBaseMap.erase(Op); |
| bool isNew = VRBaseMap.insert(std::make_pair(Op, VRBase)).second; |
| (void)isNew; // Silence compiler warning. |
| assert(isNew && "Node emitted out of order - early"); |
| } |
| |
| /// getDstOfCopyToRegUse - If the only use of the specified result number of |
| /// node is a CopyToReg, return its destination register. Return 0 otherwise. |
| unsigned InstrEmitter::getDstOfOnlyCopyToRegUse(SDNode *Node, |
| unsigned ResNo) const { |
| if (!Node->hasOneUse()) |
| return 0; |
| |
| SDNode *User = *Node->use_begin(); |
| if (User->getOpcode() == ISD::CopyToReg && |
| User->getOperand(2).getNode() == Node && |
| User->getOperand(2).getResNo() == ResNo) { |
| unsigned Reg = cast<RegisterSDNode>(User->getOperand(1))->getReg(); |
| if (TargetRegisterInfo::isVirtualRegister(Reg)) |
| return Reg; |
| } |
| return 0; |
| } |
| |
| void InstrEmitter::CreateVirtualRegisters(SDNode *Node, |
| MachineInstrBuilder &MIB, |
| const MCInstrDesc &II, |
| bool IsClone, bool IsCloned, |
| DenseMap<SDValue, unsigned> &VRBaseMap) { |
| assert(Node->getMachineOpcode() != TargetOpcode::IMPLICIT_DEF && |
| "IMPLICIT_DEF should have been handled as a special case elsewhere!"); |
| |
| for (unsigned i = 0; i < II.getNumDefs(); ++i) { |
| // If the specific node value is only used by a CopyToReg and the dest reg |
| // is a vreg in the same register class, use the CopyToReg'd destination |
| // register instead of creating a new vreg. |
| unsigned VRBase = 0; |
| const TargetRegisterClass *RC = |
| TRI->getAllocatableClass(TII->getRegClass(II, i, TRI, *MF)); |
| if (II.OpInfo[i].isOptionalDef()) { |
| // Optional def must be a physical register. |
| unsigned NumResults = CountResults(Node); |
| VRBase = cast<RegisterSDNode>(Node->getOperand(i-NumResults))->getReg(); |
| assert(TargetRegisterInfo::isPhysicalRegister(VRBase)); |
| MIB.addReg(VRBase, RegState::Define); |
| } |
| |
| if (!VRBase && !IsClone && !IsCloned) |
| for (SDNode::use_iterator UI = Node->use_begin(), E = Node->use_end(); |
| UI != E; ++UI) { |
| SDNode *User = *UI; |
| if (User->getOpcode() == ISD::CopyToReg && |
| User->getOperand(2).getNode() == Node && |
| User->getOperand(2).getResNo() == i) { |
| unsigned Reg = cast<RegisterSDNode>(User->getOperand(1))->getReg(); |
| if (TargetRegisterInfo::isVirtualRegister(Reg)) { |
| const TargetRegisterClass *RegRC = MRI->getRegClass(Reg); |
| if (RegRC == RC) { |
| VRBase = Reg; |
| MIB.addReg(VRBase, RegState::Define); |
| break; |
| } |
| } |
| } |
| } |
| |
| // Create the result registers for this node and add the result regs to |
| // the machine instruction. |
| if (VRBase == 0) { |
| assert(RC && "Isn't a register operand!"); |
| VRBase = MRI->createVirtualRegister(RC); |
| MIB.addReg(VRBase, RegState::Define); |
| } |
| |
| SDValue Op(Node, i); |
| if (IsClone) |
| VRBaseMap.erase(Op); |
| bool isNew = VRBaseMap.insert(std::make_pair(Op, VRBase)).second; |
| (void)isNew; // Silence compiler warning. |
| assert(isNew && "Node emitted out of order - early"); |
| } |
| } |
| |
| /// getVR - Return the virtual register corresponding to the specified result |
| /// of the specified node. |
| unsigned InstrEmitter::getVR(SDValue Op, |
| DenseMap<SDValue, unsigned> &VRBaseMap) { |
| if (Op.isMachineOpcode() && |
| Op.getMachineOpcode() == TargetOpcode::IMPLICIT_DEF) { |
| // Add an IMPLICIT_DEF instruction before every use. |
| unsigned VReg = getDstOfOnlyCopyToRegUse(Op.getNode(), Op.getResNo()); |
| // IMPLICIT_DEF can produce any type of result so its MCInstrDesc |
| // does not include operand register class info. |
| if (!VReg) { |
| const TargetRegisterClass *RC = |
| TLI->getRegClassFor(Op.getSimpleValueType()); |
| VReg = MRI->createVirtualRegister(RC); |
| } |
| BuildMI(*MBB, InsertPos, Op.getDebugLoc(), |
| TII->get(TargetOpcode::IMPLICIT_DEF), VReg); |
| return VReg; |
| } |
| |
| DenseMap<SDValue, unsigned>::iterator I = VRBaseMap.find(Op); |
| assert(I != VRBaseMap.end() && "Node emitted out of order - late"); |
| return I->second; |
| } |
| |
| |
| /// AddRegisterOperand - Add the specified register as an operand to the |
| /// specified machine instr. Insert register copies if the register is |
| /// not in the required register class. |
| void |
| InstrEmitter::AddRegisterOperand(MachineInstrBuilder &MIB, |
| SDValue Op, |
| unsigned IIOpNum, |
| const MCInstrDesc *II, |
| DenseMap<SDValue, unsigned> &VRBaseMap, |
| bool IsDebug, bool IsClone, bool IsCloned) { |
| assert(Op.getValueType() != MVT::Other && |
| Op.getValueType() != MVT::Glue && |
| "Chain and glue operands should occur at end of operand list!"); |
| // Get/emit the operand. |
| unsigned VReg = getVR(Op, VRBaseMap); |
| assert(TargetRegisterInfo::isVirtualRegister(VReg) && "Not a vreg?"); |
| |
| const MCInstrDesc &MCID = MIB->getDesc(); |
| bool isOptDef = IIOpNum < MCID.getNumOperands() && |
| MCID.OpInfo[IIOpNum].isOptionalDef(); |
| |
| // If the instruction requires a register in a different class, create |
| // a new virtual register and copy the value into it, but first attempt to |
| // shrink VReg's register class within reason. For example, if VReg == GR32 |
| // and II requires a GR32_NOSP, just constrain VReg to GR32_NOSP. |
| if (II) { |
| const TargetRegisterClass *DstRC = 0; |
| if (IIOpNum < II->getNumOperands()) |
| DstRC = TRI->getAllocatableClass(TII->getRegClass(*II,IIOpNum,TRI,*MF)); |
| if (DstRC && !MRI->constrainRegClass(VReg, DstRC, MinRCSize)) { |
| unsigned NewVReg = MRI->createVirtualRegister(DstRC); |
| BuildMI(*MBB, InsertPos, Op.getNode()->getDebugLoc(), |
| TII->get(TargetOpcode::COPY), NewVReg).addReg(VReg); |
| VReg = NewVReg; |
| } |
| } |
| |
| // If this value has only one use, that use is a kill. This is a |
| // conservative approximation. InstrEmitter does trivial coalescing |
| // with CopyFromReg nodes, so don't emit kill flags for them. |
| // Avoid kill flags on Schedule cloned nodes, since there will be |
| // multiple uses. |
| // Tied operands are never killed, so we need to check that. And that |
| // means we need to determine the index of the operand. |
| bool isKill = Op.hasOneUse() && |
| Op.getNode()->getOpcode() != ISD::CopyFromReg && |
| !IsDebug && |
| !(IsClone || IsCloned); |
| if (isKill) { |
| unsigned Idx = MIB->getNumOperands(); |
| while (Idx > 0 && |
| MIB->getOperand(Idx-1).isReg() && |
| MIB->getOperand(Idx-1).isImplicit()) |
| --Idx; |
| bool isTied = MCID.getOperandConstraint(Idx, MCOI::TIED_TO) != -1; |
| if (isTied) |
| isKill = false; |
| } |
| |
| MIB.addReg(VReg, getDefRegState(isOptDef) | getKillRegState(isKill) | |
| getDebugRegState(IsDebug)); |
| } |
| |
| /// AddOperand - Add the specified operand to the specified machine instr. II |
| /// specifies the instruction information for the node, and IIOpNum is the |
| /// operand number (in the II) that we are adding. |
| void InstrEmitter::AddOperand(MachineInstrBuilder &MIB, |
| SDValue Op, |
| unsigned IIOpNum, |
| const MCInstrDesc *II, |
| DenseMap<SDValue, unsigned> &VRBaseMap, |
| bool IsDebug, bool IsClone, bool IsCloned) { |
| if (Op.isMachineOpcode()) { |
| AddRegisterOperand(MIB, Op, IIOpNum, II, VRBaseMap, |
| IsDebug, IsClone, IsCloned); |
| } else if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op)) { |
| MIB.addImm(C->getSExtValue()); |
| } else if (ConstantFPSDNode *F = dyn_cast<ConstantFPSDNode>(Op)) { |
| MIB.addFPImm(F->getConstantFPValue()); |
| } else if (RegisterSDNode *R = dyn_cast<RegisterSDNode>(Op)) { |
| // Turn additional physreg operands into implicit uses on non-variadic |
| // instructions. This is used by call and return instructions passing |
| // arguments in registers. |
| bool Imp = II && (IIOpNum >= II->getNumOperands() && !II->isVariadic()); |
| MIB.addReg(R->getReg(), getImplRegState(Imp)); |
| } else if (RegisterMaskSDNode *RM = dyn_cast<RegisterMaskSDNode>(Op)) { |
| MIB.addRegMask(RM->getRegMask()); |
| } else if (GlobalAddressSDNode *TGA = dyn_cast<GlobalAddressSDNode>(Op)) { |
| MIB.addGlobalAddress(TGA->getGlobal(), TGA->getOffset(), |
| TGA->getTargetFlags()); |
| } else if (BasicBlockSDNode *BBNode = dyn_cast<BasicBlockSDNode>(Op)) { |
| MIB.addMBB(BBNode->getBasicBlock()); |
| } else if (FrameIndexSDNode *FI = dyn_cast<FrameIndexSDNode>(Op)) { |
| MIB.addFrameIndex(FI->getIndex()); |
| } else if (JumpTableSDNode *JT = dyn_cast<JumpTableSDNode>(Op)) { |
| MIB.addJumpTableIndex(JT->getIndex(), JT->getTargetFlags()); |
| } else if (ConstantPoolSDNode *CP = dyn_cast<ConstantPoolSDNode>(Op)) { |
| int Offset = CP->getOffset(); |
| unsigned Align = CP->getAlignment(); |
| Type *Type = CP->getType(); |
| // MachineConstantPool wants an explicit alignment. |
| if (Align == 0) { |
| Align = TM->getDataLayout()->getPrefTypeAlignment(Type); |
| if (Align == 0) { |
| // Alignment of vector types. FIXME! |
| Align = TM->getDataLayout()->getTypeAllocSize(Type); |
| } |
| } |
| |
| unsigned Idx; |
| MachineConstantPool *MCP = MF->getConstantPool(); |
| if (CP->isMachineConstantPoolEntry()) |
| Idx = MCP->getConstantPoolIndex(CP->getMachineCPVal(), Align); |
| else |
| Idx = MCP->getConstantPoolIndex(CP->getConstVal(), Align); |
| MIB.addConstantPoolIndex(Idx, Offset, CP->getTargetFlags()); |
| } else if (ExternalSymbolSDNode *ES = dyn_cast<ExternalSymbolSDNode>(Op)) { |
| MIB.addExternalSymbol(ES->getSymbol(), ES->getTargetFlags()); |
| } else if (BlockAddressSDNode *BA = dyn_cast<BlockAddressSDNode>(Op)) { |
| MIB.addBlockAddress(BA->getBlockAddress(), |
| BA->getOffset(), |
| BA->getTargetFlags()); |
| } else if (TargetIndexSDNode *TI = dyn_cast<TargetIndexSDNode>(Op)) { |
| MIB.addTargetIndex(TI->getIndex(), TI->getOffset(), TI->getTargetFlags()); |
| } else { |
| assert(Op.getValueType() != MVT::Other && |
| Op.getValueType() != MVT::Glue && |
| "Chain and glue operands should occur at end of operand list!"); |
| AddRegisterOperand(MIB, Op, IIOpNum, II, VRBaseMap, |
| IsDebug, IsClone, IsCloned); |
| } |
| } |
| |
| unsigned InstrEmitter::ConstrainForSubReg(unsigned VReg, unsigned SubIdx, |
| MVT VT, DebugLoc DL) { |
| const TargetRegisterClass *VRC = MRI->getRegClass(VReg); |
| const TargetRegisterClass *RC = TRI->getSubClassWithSubReg(VRC, SubIdx); |
| |
| // RC is a sub-class of VRC that supports SubIdx. Try to constrain VReg |
| // within reason. |
| if (RC && RC != VRC) |
| RC = MRI->constrainRegClass(VReg, RC, MinRCSize); |
| |
| // VReg has been adjusted. It can be used with SubIdx operands now. |
| if (RC) |
| return VReg; |
| |
| // VReg couldn't be reasonably constrained. Emit a COPY to a new virtual |
| // register instead. |
| RC = TRI->getSubClassWithSubReg(TLI->getRegClassFor(VT), SubIdx); |
| assert(RC && "No legal register class for VT supports that SubIdx"); |
| unsigned NewReg = MRI->createVirtualRegister(RC); |
| BuildMI(*MBB, InsertPos, DL, TII->get(TargetOpcode::COPY), NewReg) |
| .addReg(VReg); |
| return NewReg; |
| } |
| |
| /// EmitSubregNode - Generate machine code for subreg nodes. |
| /// |
| void InstrEmitter::EmitSubregNode(SDNode *Node, |
| DenseMap<SDValue, unsigned> &VRBaseMap, |
| bool IsClone, bool IsCloned) { |
| unsigned VRBase = 0; |
| unsigned Opc = Node->getMachineOpcode(); |
| |
| // If the node is only used by a CopyToReg and the dest reg is a vreg, use |
| // the CopyToReg'd destination register instead of creating a new vreg. |
| for (SDNode::use_iterator UI = Node->use_begin(), E = Node->use_end(); |
| UI != E; ++UI) { |
| SDNode *User = *UI; |
| if (User->getOpcode() == ISD::CopyToReg && |
| User->getOperand(2).getNode() == Node) { |
| unsigned DestReg = cast<RegisterSDNode>(User->getOperand(1))->getReg(); |
| if (TargetRegisterInfo::isVirtualRegister(DestReg)) { |
| VRBase = DestReg; |
| break; |
| } |
| } |
| } |
| |
| if (Opc == TargetOpcode::EXTRACT_SUBREG) { |
| // EXTRACT_SUBREG is lowered as %dst = COPY %src:sub. There are no |
| // constraints on the %dst register, COPY can target all legal register |
| // classes. |
| unsigned SubIdx = cast<ConstantSDNode>(Node->getOperand(1))->getZExtValue(); |
| const TargetRegisterClass *TRC = |
| TLI->getRegClassFor(Node->getSimpleValueType(0)); |
| |
| unsigned VReg = getVR(Node->getOperand(0), VRBaseMap); |
| MachineInstr *DefMI = MRI->getVRegDef(VReg); |
| unsigned SrcReg, DstReg, DefSubIdx; |
| if (DefMI && |
| TII->isCoalescableExtInstr(*DefMI, SrcReg, DstReg, DefSubIdx) && |
| SubIdx == DefSubIdx && |
| TRC == MRI->getRegClass(SrcReg)) { |
| // Optimize these: |
| // r1025 = s/zext r1024, 4 |
| // r1026 = extract_subreg r1025, 4 |
| // to a copy |
| // r1026 = copy r1024 |
| VRBase = MRI->createVirtualRegister(TRC); |
| BuildMI(*MBB, InsertPos, Node->getDebugLoc(), |
| TII->get(TargetOpcode::COPY), VRBase).addReg(SrcReg); |
| MRI->clearKillFlags(SrcReg); |
| } else { |
| // VReg may not support a SubIdx sub-register, and we may need to |
| // constrain its register class or issue a COPY to a compatible register |
| // class. |
| VReg = ConstrainForSubReg(VReg, SubIdx, |
| Node->getOperand(0).getSimpleValueType(), |
| Node->getDebugLoc()); |
| |
| // Create the destreg if it is missing. |
| if (VRBase == 0) |
| VRBase = MRI->createVirtualRegister(TRC); |
| |
| // Create the extract_subreg machine instruction. |
| BuildMI(*MBB, InsertPos, Node->getDebugLoc(), |
| TII->get(TargetOpcode::COPY), VRBase).addReg(VReg, 0, SubIdx); |
| } |
| } else if (Opc == TargetOpcode::INSERT_SUBREG || |
| Opc == TargetOpcode::SUBREG_TO_REG) { |
| SDValue N0 = Node->getOperand(0); |
| SDValue N1 = Node->getOperand(1); |
| SDValue N2 = Node->getOperand(2); |
| unsigned SubIdx = cast<ConstantSDNode>(N2)->getZExtValue(); |
| |
| // Figure out the register class to create for the destreg. It should be |
| // the largest legal register class supporting SubIdx sub-registers. |
| // RegisterCoalescer will constrain it further if it decides to eliminate |
| // the INSERT_SUBREG instruction. |
| // |
| // %dst = INSERT_SUBREG %src, %sub, SubIdx |
| // |
| // is lowered by TwoAddressInstructionPass to: |
| // |
| // %dst = COPY %src |
| // %dst:SubIdx = COPY %sub |
| // |
| // There is no constraint on the %src register class. |
| // |
| const TargetRegisterClass *SRC = TLI->getRegClassFor(Node->getSimpleValueType(0)); |
| SRC = TRI->getSubClassWithSubReg(SRC, SubIdx); |
| assert(SRC && "No register class supports VT and SubIdx for INSERT_SUBREG"); |
| |
| if (VRBase == 0 || !SRC->hasSubClassEq(MRI->getRegClass(VRBase))) |
| VRBase = MRI->createVirtualRegister(SRC); |
| |
| // Create the insert_subreg or subreg_to_reg machine instruction. |
| MachineInstrBuilder MIB = |
| BuildMI(*MF, Node->getDebugLoc(), TII->get(Opc), VRBase); |
| |
| // If creating a subreg_to_reg, then the first input operand |
| // is an implicit value immediate, otherwise it's a register |
| if (Opc == TargetOpcode::SUBREG_TO_REG) { |
| const ConstantSDNode *SD = cast<ConstantSDNode>(N0); |
| MIB.addImm(SD->getZExtValue()); |
| } else |
| AddOperand(MIB, N0, 0, 0, VRBaseMap, /*IsDebug=*/false, |
| IsClone, IsCloned); |
| // Add the subregster being inserted |
| AddOperand(MIB, N1, 0, 0, VRBaseMap, /*IsDebug=*/false, |
| IsClone, IsCloned); |
| MIB.addImm(SubIdx); |
| MBB->insert(InsertPos, MIB); |
| } else |
| llvm_unreachable("Node is not insert_subreg, extract_subreg, or subreg_to_reg"); |
| |
| SDValue Op(Node, 0); |
| bool isNew = VRBaseMap.insert(std::make_pair(Op, VRBase)).second; |
| (void)isNew; // Silence compiler warning. |
| assert(isNew && "Node emitted out of order - early"); |
| } |
| |
| /// EmitCopyToRegClassNode - Generate machine code for COPY_TO_REGCLASS nodes. |
| /// COPY_TO_REGCLASS is just a normal copy, except that the destination |
| /// register is constrained to be in a particular register class. |
| /// |
| void |
| InstrEmitter::EmitCopyToRegClassNode(SDNode *Node, |
| DenseMap<SDValue, unsigned> &VRBaseMap) { |
| unsigned VReg = getVR(Node->getOperand(0), VRBaseMap); |
| |
| // Create the new VReg in the destination class and emit a copy. |
| unsigned DstRCIdx = cast<ConstantSDNode>(Node->getOperand(1))->getZExtValue(); |
| const TargetRegisterClass *DstRC = |
| TRI->getAllocatableClass(TRI->getRegClass(DstRCIdx)); |
| unsigned NewVReg = MRI->createVirtualRegister(DstRC); |
| BuildMI(*MBB, InsertPos, Node->getDebugLoc(), TII->get(TargetOpcode::COPY), |
| NewVReg).addReg(VReg); |
| |
| SDValue Op(Node, 0); |
| bool isNew = VRBaseMap.insert(std::make_pair(Op, NewVReg)).second; |
| (void)isNew; // Silence compiler warning. |
| assert(isNew && "Node emitted out of order - early"); |
| } |
| |
| /// EmitRegSequence - Generate machine code for REG_SEQUENCE nodes. |
| /// |
| void InstrEmitter::EmitRegSequence(SDNode *Node, |
| DenseMap<SDValue, unsigned> &VRBaseMap, |
| bool IsClone, bool IsCloned) { |
| unsigned DstRCIdx = cast<ConstantSDNode>(Node->getOperand(0))->getZExtValue(); |
| const TargetRegisterClass *RC = TRI->getRegClass(DstRCIdx); |
| unsigned NewVReg = MRI->createVirtualRegister(TRI->getAllocatableClass(RC)); |
| const MCInstrDesc &II = TII->get(TargetOpcode::REG_SEQUENCE); |
| MachineInstrBuilder MIB = BuildMI(*MF, Node->getDebugLoc(), II, NewVReg); |
| unsigned NumOps = Node->getNumOperands(); |
| assert((NumOps & 1) == 1 && |
| "REG_SEQUENCE must have an odd number of operands!"); |
| for (unsigned i = 1; i != NumOps; ++i) { |
| SDValue Op = Node->getOperand(i); |
| if ((i & 1) == 0) { |
| RegisterSDNode *R = dyn_cast<RegisterSDNode>(Node->getOperand(i-1)); |
| // Skip physical registers as they don't have a vreg to get and we'll |
| // insert copies for them in TwoAddressInstructionPass anyway. |
| if (!R || !TargetRegisterInfo::isPhysicalRegister(R->getReg())) { |
| unsigned SubIdx = cast<ConstantSDNode>(Op)->getZExtValue(); |
| unsigned SubReg = getVR(Node->getOperand(i-1), VRBaseMap); |
| const TargetRegisterClass *TRC = MRI->getRegClass(SubReg); |
| const TargetRegisterClass *SRC = |
| TRI->getMatchingSuperRegClass(RC, TRC, SubIdx); |
| if (SRC && SRC != RC) { |
| MRI->setRegClass(NewVReg, SRC); |
| RC = SRC; |
| } |
| } |
| } |
| AddOperand(MIB, Op, i+1, &II, VRBaseMap, /*IsDebug=*/false, |
| IsClone, IsCloned); |
| } |
| |
| MBB->insert(InsertPos, MIB); |
| SDValue Op(Node, 0); |
| bool isNew = VRBaseMap.insert(std::make_pair(Op, NewVReg)).second; |
| (void)isNew; // Silence compiler warning. |
| assert(isNew && "Node emitted out of order - early"); |
| } |
| |
| /// EmitDbgValue - Generate machine instruction for a dbg_value node. |
| /// |
| MachineInstr * |
| InstrEmitter::EmitDbgValue(SDDbgValue *SD, |
| DenseMap<SDValue, unsigned> &VRBaseMap) { |
| uint64_t Offset = SD->getOffset(); |
| MDNode* MDPtr = SD->getMDPtr(); |
| DebugLoc DL = SD->getDebugLoc(); |
| |
| if (SD->getKind() == SDDbgValue::FRAMEIX) { |
| // Stack address; this needs to be lowered in target-dependent fashion. |
| // EmitTargetCodeForFrameDebugValue is responsible for allocation. |
| unsigned FrameIx = SD->getFrameIx(); |
| return TII->emitFrameIndexDebugValue(*MF, FrameIx, Offset, MDPtr, DL); |
| } |
| // Otherwise, we're going to create an instruction here. |
| const MCInstrDesc &II = TII->get(TargetOpcode::DBG_VALUE); |
| MachineInstrBuilder MIB = BuildMI(*MF, DL, II); |
| if (SD->getKind() == SDDbgValue::SDNODE) { |
| SDNode *Node = SD->getSDNode(); |
| SDValue Op = SDValue(Node, SD->getResNo()); |
| // It's possible we replaced this SDNode with other(s) and therefore |
| // didn't generate code for it. It's better to catch these cases where |
| // they happen and transfer the debug info, but trying to guarantee that |
| // in all cases would be very fragile; this is a safeguard for any |
| // that were missed. |
| DenseMap<SDValue, unsigned>::iterator I = VRBaseMap.find(Op); |
| if (I==VRBaseMap.end()) |
| MIB.addReg(0U); // undef |
| else |
| AddOperand(MIB, Op, (*MIB).getNumOperands(), &II, VRBaseMap, |
| /*IsDebug=*/true, /*IsClone=*/false, /*IsCloned=*/false); |
| } else if (SD->getKind() == SDDbgValue::CONST) { |
| const Value *V = SD->getConst(); |
| if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) { |
| if (CI->getBitWidth() > 64) |
| MIB.addCImm(CI); |
| else |
| MIB.addImm(CI->getSExtValue()); |
| } else if (const ConstantFP *CF = dyn_cast<ConstantFP>(V)) { |
| MIB.addFPImm(CF); |
| } else { |
| // Could be an Undef. In any case insert an Undef so we can see what we |
| // dropped. |
| MIB.addReg(0U); |
| } |
| } else { |
| // Insert an Undef so we can see what we dropped. |
| MIB.addReg(0U); |
| } |
| |
| MIB.addImm(Offset).addMetadata(MDPtr); |
| return &*MIB; |
| } |
| |
| /// EmitMachineNode - Generate machine code for a target-specific node and |
| /// needed dependencies. |
| /// |
| void InstrEmitter:: |
| EmitMachineNode(SDNode *Node, bool IsClone, bool IsCloned, |
| DenseMap<SDValue, unsigned> &VRBaseMap) { |
| unsigned Opc = Node->getMachineOpcode(); |
| |
| // Handle subreg insert/extract specially |
| if (Opc == TargetOpcode::EXTRACT_SUBREG || |
| Opc == TargetOpcode::INSERT_SUBREG || |
| Opc == TargetOpcode::SUBREG_TO_REG) { |
| EmitSubregNode(Node, VRBaseMap, IsClone, IsCloned); |
| return; |
| } |
| |
| // Handle COPY_TO_REGCLASS specially. |
| if (Opc == TargetOpcode::COPY_TO_REGCLASS) { |
| EmitCopyToRegClassNode(Node, VRBaseMap); |
| return; |
| } |
| |
| // Handle REG_SEQUENCE specially. |
| if (Opc == TargetOpcode::REG_SEQUENCE) { |
| EmitRegSequence(Node, VRBaseMap, IsClone, IsCloned); |
| return; |
| } |
| |
| if (Opc == TargetOpcode::IMPLICIT_DEF) |
| // We want a unique VR for each IMPLICIT_DEF use. |
| return; |
| |
| const MCInstrDesc &II = TII->get(Opc); |
| unsigned NumResults = CountResults(Node); |
| unsigned NumImpUses = 0; |
| unsigned NodeOperands = |
| countOperands(Node, II.getNumOperands() - II.getNumDefs(), NumImpUses); |
| bool HasPhysRegOuts = NumResults > II.getNumDefs() && II.getImplicitDefs()!=0; |
| #ifndef NDEBUG |
| unsigned NumMIOperands = NodeOperands + NumResults; |
| if (II.isVariadic()) |
| assert(NumMIOperands >= II.getNumOperands() && |
| "Too few operands for a variadic node!"); |
| else |
| assert(NumMIOperands >= II.getNumOperands() && |
| NumMIOperands <= II.getNumOperands() + II.getNumImplicitDefs() + |
| NumImpUses && |
| "#operands for dag node doesn't match .td file!"); |
| #endif |
| |
| // Create the new machine instruction. |
| MachineInstrBuilder MIB = BuildMI(*MF, Node->getDebugLoc(), II); |
| |
| // Add result register values for things that are defined by this |
| // instruction. |
| if (NumResults) |
| CreateVirtualRegisters(Node, MIB, II, IsClone, IsCloned, VRBaseMap); |
| |
| // Emit all of the actual operands of this instruction, adding them to the |
| // instruction as appropriate. |
| bool HasOptPRefs = II.getNumDefs() > NumResults; |
| assert((!HasOptPRefs || !HasPhysRegOuts) && |
| "Unable to cope with optional defs and phys regs defs!"); |
| unsigned NumSkip = HasOptPRefs ? II.getNumDefs() - NumResults : 0; |
| for (unsigned i = NumSkip; i != NodeOperands; ++i) |
| AddOperand(MIB, Node->getOperand(i), i-NumSkip+II.getNumDefs(), &II, |
| VRBaseMap, /*IsDebug=*/false, IsClone, IsCloned); |
| |
| // Transfer all of the memory reference descriptions of this instruction. |
| MIB.setMemRefs(cast<MachineSDNode>(Node)->memoperands_begin(), |
| cast<MachineSDNode>(Node)->memoperands_end()); |
| |
| // Insert the instruction into position in the block. This needs to |
| // happen before any custom inserter hook is called so that the |
| // hook knows where in the block to insert the replacement code. |
| MBB->insert(InsertPos, MIB); |
| |
| // The MachineInstr may also define physregs instead of virtregs. These |
| // physreg values can reach other instructions in different ways: |
| // |
| // 1. When there is a use of a Node value beyond the explicitly defined |
| // virtual registers, we emit a CopyFromReg for one of the implicitly |
| // defined physregs. This only happens when HasPhysRegOuts is true. |
| // |
| // 2. A CopyFromReg reading a physreg may be glued to this instruction. |
| // |
| // 3. A glued instruction may implicitly use a physreg. |
| // |
| // 4. A glued instruction may use a RegisterSDNode operand. |
| // |
| // Collect all the used physreg defs, and make sure that any unused physreg |
| // defs are marked as dead. |
| SmallVector<unsigned, 8> UsedRegs; |
| |
| // Additional results must be physical register defs. |
| if (HasPhysRegOuts) { |
| for (unsigned i = II.getNumDefs(); i < NumResults; ++i) { |
| unsigned Reg = II.getImplicitDefs()[i - II.getNumDefs()]; |
| if (!Node->hasAnyUseOfValue(i)) |
| continue; |
| // This implicitly defined physreg has a use. |
| UsedRegs.push_back(Reg); |
| EmitCopyFromReg(Node, i, IsClone, IsCloned, Reg, VRBaseMap); |
| } |
| } |
| |
| // Scan the glue chain for any used physregs. |
| if (Node->getValueType(Node->getNumValues()-1) == MVT::Glue) { |
| for (SDNode *F = Node->getGluedUser(); F; F = F->getGluedUser()) { |
| if (F->getOpcode() == ISD::CopyFromReg) { |
| UsedRegs.push_back(cast<RegisterSDNode>(F->getOperand(1))->getReg()); |
| continue; |
| } else if (F->getOpcode() == ISD::CopyToReg) { |
| // Skip CopyToReg nodes that are internal to the glue chain. |
| continue; |
| } |
| // Collect declared implicit uses. |
| const MCInstrDesc &MCID = TII->get(F->getMachineOpcode()); |
| UsedRegs.append(MCID.getImplicitUses(), |
| MCID.getImplicitUses() + MCID.getNumImplicitUses()); |
| // In addition to declared implicit uses, we must also check for |
| // direct RegisterSDNode operands. |
| for (unsigned i = 0, e = F->getNumOperands(); i != e; ++i) |
| if (RegisterSDNode *R = dyn_cast<RegisterSDNode>(F->getOperand(i))) { |
| unsigned Reg = R->getReg(); |
| if (TargetRegisterInfo::isPhysicalRegister(Reg)) |
| UsedRegs.push_back(Reg); |
| } |
| } |
| } |
| |
| // Finally mark unused registers as dead. |
| if (!UsedRegs.empty() || II.getImplicitDefs()) |
| MIB->setPhysRegsDeadExcept(UsedRegs, *TRI); |
| |
| // Run post-isel target hook to adjust this instruction if needed. |
| #ifdef NDEBUG |
| if (II.hasPostISelHook()) |
| #endif |
| TLI->AdjustInstrPostInstrSelection(MIB, Node); |
| } |
| |
| /// EmitSpecialNode - Generate machine code for a target-independent node and |
| /// needed dependencies. |
| void InstrEmitter:: |
| EmitSpecialNode(SDNode *Node, bool IsClone, bool IsCloned, |
| DenseMap<SDValue, unsigned> &VRBaseMap) { |
| switch (Node->getOpcode()) { |
| default: |
| #ifndef NDEBUG |
| Node->dump(); |
| #endif |
| llvm_unreachable("This target-independent node should have been selected!"); |
| case ISD::EntryToken: |
| llvm_unreachable("EntryToken should have been excluded from the schedule!"); |
| case ISD::MERGE_VALUES: |
| case ISD::TokenFactor: // fall thru |
| break; |
| case ISD::CopyToReg: { |
| unsigned SrcReg; |
| SDValue SrcVal = Node->getOperand(2); |
| if (RegisterSDNode *R = dyn_cast<RegisterSDNode>(SrcVal)) |
| SrcReg = R->getReg(); |
| else |
| SrcReg = getVR(SrcVal, VRBaseMap); |
| |
| unsigned DestReg = cast<RegisterSDNode>(Node->getOperand(1))->getReg(); |
| if (SrcReg == DestReg) // Coalesced away the copy? Ignore. |
| break; |
| |
| BuildMI(*MBB, InsertPos, Node->getDebugLoc(), TII->get(TargetOpcode::COPY), |
| DestReg).addReg(SrcReg); |
| break; |
| } |
| case ISD::CopyFromReg: { |
| unsigned SrcReg = cast<RegisterSDNode>(Node->getOperand(1))->getReg(); |
| EmitCopyFromReg(Node, 0, IsClone, IsCloned, SrcReg, VRBaseMap); |
| break; |
| } |
| case ISD::EH_LABEL: { |
| MCSymbol *S = cast<EHLabelSDNode>(Node)->getLabel(); |
| BuildMI(*MBB, InsertPos, Node->getDebugLoc(), |
| TII->get(TargetOpcode::EH_LABEL)).addSym(S); |
| break; |
| } |
| |
| case ISD::LIFETIME_START: |
| case ISD::LIFETIME_END: { |
| unsigned TarOp = (Node->getOpcode() == ISD::LIFETIME_START) ? |
| TargetOpcode::LIFETIME_START : TargetOpcode::LIFETIME_END; |
| |
| FrameIndexSDNode *FI = dyn_cast<FrameIndexSDNode>(Node->getOperand(1)); |
| BuildMI(*MBB, InsertPos, Node->getDebugLoc(), TII->get(TarOp)) |
| .addFrameIndex(FI->getIndex()); |
| break; |
| } |
| |
| case ISD::INLINEASM: { |
| unsigned NumOps = Node->getNumOperands(); |
| if (Node->getOperand(NumOps-1).getValueType() == MVT::Glue) |
| --NumOps; // Ignore the glue operand. |
| |
| // Create the inline asm machine instruction. |
| MachineInstrBuilder MIB = BuildMI(*MF, Node->getDebugLoc(), |
| TII->get(TargetOpcode::INLINEASM)); |
| |
| // Add the asm string as an external symbol operand. |
| SDValue AsmStrV = Node->getOperand(InlineAsm::Op_AsmString); |
| const char *AsmStr = cast<ExternalSymbolSDNode>(AsmStrV)->getSymbol(); |
| MIB.addExternalSymbol(AsmStr); |
| |
| // Add the HasSideEffect, isAlignStack, AsmDialect, MayLoad and MayStore |
| // bits. |
| int64_t ExtraInfo = |
| cast<ConstantSDNode>(Node->getOperand(InlineAsm::Op_ExtraInfo))-> |
| getZExtValue(); |
| MIB.addImm(ExtraInfo); |
| |
| // Remember to operand index of the group flags. |
| SmallVector<unsigned, 8> GroupIdx; |
| |
| // Add all of the operand registers to the instruction. |
| for (unsigned i = InlineAsm::Op_FirstOperand; i != NumOps;) { |
| unsigned Flags = |
| cast<ConstantSDNode>(Node->getOperand(i))->getZExtValue(); |
| const unsigned NumVals = InlineAsm::getNumOperandRegisters(Flags); |
| |
| GroupIdx.push_back(MIB->getNumOperands()); |
| MIB.addImm(Flags); |
| ++i; // Skip the ID value. |
| |
| switch (InlineAsm::getKind(Flags)) { |
| default: llvm_unreachable("Bad flags!"); |
| case InlineAsm::Kind_RegDef: |
| for (unsigned j = 0; j != NumVals; ++j, ++i) { |
| unsigned Reg = cast<RegisterSDNode>(Node->getOperand(i))->getReg(); |
| // FIXME: Add dead flags for physical and virtual registers defined. |
| // For now, mark physical register defs as implicit to help fast |
| // regalloc. This makes inline asm look a lot like calls. |
| MIB.addReg(Reg, RegState::Define | |
| getImplRegState(TargetRegisterInfo::isPhysicalRegister(Reg))); |
| } |
| break; |
| case InlineAsm::Kind_RegDefEarlyClobber: |
| case InlineAsm::Kind_Clobber: |
| for (unsigned j = 0; j != NumVals; ++j, ++i) { |
| unsigned Reg = cast<RegisterSDNode>(Node->getOperand(i))->getReg(); |
| MIB.addReg(Reg, RegState::Define | RegState::EarlyClobber | |
| getImplRegState(TargetRegisterInfo::isPhysicalRegister(Reg))); |
| } |
| break; |
| case InlineAsm::Kind_RegUse: // Use of register. |
| case InlineAsm::Kind_Imm: // Immediate. |
| case InlineAsm::Kind_Mem: // Addressing mode. |
| // The addressing mode has been selected, just add all of the |
| // operands to the machine instruction. |
| for (unsigned j = 0; j != NumVals; ++j, ++i) |
| AddOperand(MIB, Node->getOperand(i), 0, 0, VRBaseMap, |
| /*IsDebug=*/false, IsClone, IsCloned); |
| |
| // Manually set isTied bits. |
| if (InlineAsm::getKind(Flags) == InlineAsm::Kind_RegUse) { |
| unsigned DefGroup = 0; |
| if (InlineAsm::isUseOperandTiedToDef(Flags, DefGroup)) { |
| unsigned DefIdx = GroupIdx[DefGroup] + 1; |
| unsigned UseIdx = GroupIdx.back() + 1; |
| for (unsigned j = 0; j != NumVals; ++j) |
| MIB->tieOperands(DefIdx + j, UseIdx + j); |
| } |
| } |
| break; |
| } |
| } |
| |
| // Get the mdnode from the asm if it exists and add it to the instruction. |
| SDValue MDV = Node->getOperand(InlineAsm::Op_MDNode); |
| const MDNode *MD = cast<MDNodeSDNode>(MDV)->getMD(); |
| if (MD) |
| MIB.addMetadata(MD); |
| |
| MBB->insert(InsertPos, MIB); |
| break; |
| } |
| } |
| } |
| |
| /// InstrEmitter - Construct an InstrEmitter and set it to start inserting |
| /// at the given position in the given block. |
| InstrEmitter::InstrEmitter(MachineBasicBlock *mbb, |
| MachineBasicBlock::iterator insertpos) |
| : MF(mbb->getParent()), |
| MRI(&MF->getRegInfo()), |
| TM(&MF->getTarget()), |
| TII(TM->getInstrInfo()), |
| TRI(TM->getRegisterInfo()), |
| TLI(TM->getTargetLowering()), |
| MBB(mbb), InsertPos(insertpos) { |
| } |