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Diffstat (limited to 'contrib/llvm/lib/CodeGen/SelectionDAG/InstrEmitter.cpp')
| -rw-r--r-- | contrib/llvm/lib/CodeGen/SelectionDAG/InstrEmitter.cpp | 961 |
1 files changed, 961 insertions, 0 deletions
diff --git a/contrib/llvm/lib/CodeGen/SelectionDAG/InstrEmitter.cpp b/contrib/llvm/lib/CodeGen/SelectionDAG/InstrEmitter.cpp new file mode 100644 index 0000000..4488d27 --- /dev/null +++ b/contrib/llvm/lib/CodeGen/SelectionDAG/InstrEmitter.cpp @@ -0,0 +1,961 @@ +//==--- 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/CodeGen/MachineConstantPool.h" +#include "llvm/CodeGen/MachineFunction.h" +#include "llvm/CodeGen/MachineInstrBuilder.h" +#include "llvm/CodeGen/MachineRegisterInfo.h" +#include "llvm/Target/TargetData.h" +#include "llvm/Target/TargetMachine.h" +#include "llvm/Target/TargetInstrInfo.h" +#include "llvm/Target/TargetLowering.h" +#include "llvm/ADT/Statistic.h" +#include "llvm/Support/Debug.h" +#include "llvm/Support/ErrorHandling.h" +#include "llvm/Support/MathExtras.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 &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. + for (unsigned I = N; I; --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; + EVT VT = Node->getValueType(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; + EVT VT = Node->getValueType(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, MachineInstr *MI, + 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)); + MI->addOperand(MachineOperand::CreateReg(VRBase, true)); + } + + 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; + MI->addOperand(MachineOperand::CreateReg(Reg, true)); + 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); + MI->addOperand(MachineOperand::CreateReg(VRBase, true)); + } + + 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.getValueType()); + 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(MachineInstr *MI, 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 = MI->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)); + assert((DstRC || (MI->isVariadic() && IIOpNum >= MCID.getNumOperands())) && + "Don't have operand info for this instruction!"); + 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 = MI->getNumOperands(); + while (Idx > 0 && + MI->getOperand(Idx-1).isReg() && MI->getOperand(Idx-1).isImplicit()) + --Idx; + bool isTied = MI->getDesc().getOperandConstraint(Idx, MCOI::TIED_TO) != -1; + if (isTied) + isKill = false; + } + + MI->addOperand(MachineOperand::CreateReg(VReg, isOptDef, + false/*isImp*/, isKill, + false/*isDead*/, false/*isUndef*/, + false/*isEarlyClobber*/, + 0/*SubReg*/, 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(MachineInstr *MI, SDValue Op, + unsigned IIOpNum, + const MCInstrDesc *II, + DenseMap<SDValue, unsigned> &VRBaseMap, + bool IsDebug, bool IsClone, bool IsCloned) { + if (Op.isMachineOpcode()) { + AddRegisterOperand(MI, Op, IIOpNum, II, VRBaseMap, + IsDebug, IsClone, IsCloned); + } else if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op)) { + MI->addOperand(MachineOperand::CreateImm(C->getSExtValue())); + } else if (ConstantFPSDNode *F = dyn_cast<ConstantFPSDNode>(Op)) { + const ConstantFP *CFP = F->getConstantFPValue(); + MI->addOperand(MachineOperand::CreateFPImm(CFP)); + } 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()); + MI->addOperand(MachineOperand::CreateReg(R->getReg(), false, Imp)); + } else if (RegisterMaskSDNode *RM = dyn_cast<RegisterMaskSDNode>(Op)) { + MI->addOperand(MachineOperand::CreateRegMask(RM->getRegMask())); + } else if (GlobalAddressSDNode *TGA = dyn_cast<GlobalAddressSDNode>(Op)) { + MI->addOperand(MachineOperand::CreateGA(TGA->getGlobal(), TGA->getOffset(), + TGA->getTargetFlags())); + } else if (BasicBlockSDNode *BBNode = dyn_cast<BasicBlockSDNode>(Op)) { + MI->addOperand(MachineOperand::CreateMBB(BBNode->getBasicBlock())); + } else if (FrameIndexSDNode *FI = dyn_cast<FrameIndexSDNode>(Op)) { + MI->addOperand(MachineOperand::CreateFI(FI->getIndex())); + } else if (JumpTableSDNode *JT = dyn_cast<JumpTableSDNode>(Op)) { + MI->addOperand(MachineOperand::CreateJTI(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->getTargetData()->getPrefTypeAlignment(Type); + if (Align == 0) { + // Alignment of vector types. FIXME! + Align = TM->getTargetData()->getTypeAllocSize(Type); + } + } + + unsigned Idx; + MachineConstantPool *MCP = MF->getConstantPool(); + if (CP->isMachineConstantPoolEntry()) + Idx = MCP->getConstantPoolIndex(CP->getMachineCPVal(), Align); + else + Idx = MCP->getConstantPoolIndex(CP->getConstVal(), Align); + MI->addOperand(MachineOperand::CreateCPI(Idx, Offset, + CP->getTargetFlags())); + } else if (ExternalSymbolSDNode *ES = dyn_cast<ExternalSymbolSDNode>(Op)) { + MI->addOperand(MachineOperand::CreateES(ES->getSymbol(), + ES->getTargetFlags())); + } else if (BlockAddressSDNode *BA = dyn_cast<BlockAddressSDNode>(Op)) { + MI->addOperand(MachineOperand::CreateBA(BA->getBlockAddress(), + BA->getTargetFlags())); + } else if (TargetIndexSDNode *TI = dyn_cast<TargetIndexSDNode>(Op)) { + MI->addOperand(MachineOperand::CreateTargetIndex(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(MI, Op, IIOpNum, II, VRBaseMap, + IsDebug, IsClone, IsCloned); + } +} + +unsigned InstrEmitter::ConstrainForSubReg(unsigned VReg, unsigned SubIdx, + EVT 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->getValueType(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).getValueType(), + 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->getValueType(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. + MachineInstr *MI = BuildMI(*MF, Node->getDebugLoc(), TII->get(Opc)); + MI->addOperand(MachineOperand::CreateReg(VRBase, true)); + + // 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); + MI->addOperand(MachineOperand::CreateImm(SD->getZExtValue())); + } else + AddOperand(MI, N0, 0, 0, VRBaseMap, /*IsDebug=*/false, + IsClone, IsCloned); + // Add the subregster being inserted + AddOperand(MI, N1, 0, 0, VRBaseMap, /*IsDebug=*/false, + IsClone, IsCloned); + MI->addOperand(MachineOperand::CreateImm(SubIdx)); + MBB->insert(InsertPos, MI); + } 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)); + MachineInstr *MI = BuildMI(*MF, Node->getDebugLoc(), + TII->get(TargetOpcode::REG_SEQUENCE), NewVReg); + unsigned NumOps = Node->getNumOperands(); + assert((NumOps & 1) == 1 && + "REG_SEQUENCE must have an odd number of operands!"); + const MCInstrDesc &II = TII->get(TargetOpcode::REG_SEQUENCE); + 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(MI, Op, i+1, &II, VRBaseMap, /*IsDebug=*/false, + IsClone, IsCloned); + } + + MBB->insert(InsertPos, MI); + 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, 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. + MachineInstr *MI = BuildMI(*MF, Node->getDebugLoc(), II); + + // Add result register values for things that are defined by this + // instruction. + if (NumResults) + CreateVirtualRegisters(Node, MI, 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(MI, Node->getOperand(i), i-NumSkip+II.getNumDefs(), &II, + VRBaseMap, /*IsDebug=*/false, IsClone, IsCloned); + + // Transfer all of the memory reference descriptions of this instruction. + MI->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, MI); + + // 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()) + MI->setPhysRegsDeadExcept(UsedRegs, *TRI); + + // Run post-isel target hook to adjust this instruction if needed. +#ifdef NDEBUG + if (II.hasPostISelHook()) +#endif + TLI->AdjustInstrPostInstrSelection(MI, 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::INLINEASM: { + unsigned NumOps = Node->getNumOperands(); + if (Node->getOperand(NumOps-1).getValueType() == MVT::Glue) + --NumOps; // Ignore the glue operand. + + // Create the inline asm machine instruction. + MachineInstr *MI = 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(); + MI->addOperand(MachineOperand::CreateES(AsmStr)); + + // Add the HasSideEffect and isAlignStack bits. + int64_t ExtraInfo = + cast<ConstantSDNode>(Node->getOperand(InlineAsm::Op_ExtraInfo))-> + getZExtValue(); + MI->addOperand(MachineOperand::CreateImm(ExtraInfo)); + + // 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(); + unsigned NumVals = InlineAsm::getNumOperandRegisters(Flags); + + MI->addOperand(MachineOperand::CreateImm(Flags)); + ++i; // Skip the ID value. + + switch (InlineAsm::getKind(Flags)) { + default: llvm_unreachable("Bad flags!"); + case InlineAsm::Kind_RegDef: + for (; NumVals; --NumVals, ++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. + MI->addOperand(MachineOperand::CreateReg(Reg, true, + /*isImp=*/ TargetRegisterInfo::isPhysicalRegister(Reg))); + } + break; + case InlineAsm::Kind_RegDefEarlyClobber: + case InlineAsm::Kind_Clobber: + for (; NumVals; --NumVals, ++i) { + unsigned Reg = cast<RegisterSDNode>(Node->getOperand(i))->getReg(); + MI->addOperand(MachineOperand::CreateReg(Reg, /*isDef=*/ true, + /*isImp=*/ TargetRegisterInfo::isPhysicalRegister(Reg), + /*isKill=*/ false, + /*isDead=*/ false, + /*isUndef=*/false, + /*isEarlyClobber=*/ true)); + } + 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 (; NumVals; --NumVals, ++i) + AddOperand(MI, Node->getOperand(i), 0, 0, VRBaseMap, + /*IsDebug=*/false, IsClone, IsCloned); + 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) + MI->addOperand(MachineOperand::CreateMetadata(MD)); + + MBB->insert(InsertPos, MI); + 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) { +} |
