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llvm-mirror/lib/CodeGen/SelectionDAG/ScheduleDAGEmit.cpp
Dan Gohman 85d35b92df Move the code that inserts copies for function livein registers 
out of ScheduleDAGEmit.cpp and into SelectionDAGISel.cpp. This
allows it to be run exactly once per function, even if multiple
SelectionDAG iterations happen in the entry block, as may happen
with FastISel.

llvm-svn: 55863
2008-09-05 22:59:21 +00:00

670 lines
26 KiB
C++
Raw Blame History

//===---- ScheduleDAGEmit.cpp - Emit routines for the ScheduleDAG 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 ScheduleDAG class, which creates
// MachineInstrs according to the computed schedule.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "pre-RA-sched"
#include "llvm/CodeGen/ScheduleDAG.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/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/MathExtras.h"
using namespace llvm;
STATISTIC(NumCommutes, "Number of instructions commuted");
/// getInstrOperandRegClass - Return register class of the operand of an
/// instruction of the specified TargetInstrDesc.
static const TargetRegisterClass*
getInstrOperandRegClass(const TargetRegisterInfo *TRI,
const TargetInstrInfo *TII, const TargetInstrDesc &II,
unsigned Op) {
if (Op >= II.getNumOperands()) {
assert(II.isVariadic() && "Invalid operand # of instruction");
return NULL;
}
if (II.OpInfo[Op].isLookupPtrRegClass())
return TII->getPointerRegClass();
return TRI->getRegClass(II.OpInfo[Op].RegClass);
}
/// EmitCopyFromReg - Generate machine code for an CopyFromReg node or an
/// implicit physical register output.
void ScheduleDAG::EmitCopyFromReg(SDNode *Node, unsigned ResNo,
bool IsClone, 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;
isNew = 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;
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->getValueType(Op.getResNo());
if (VT != MVT::Other && VT != MVT::Flag)
Match = false;
}
}
MatchReg &= Match;
if (VRBase)
break;
}
const TargetRegisterClass *SrcRC = 0, *DstRC = 0;
SrcRC = TRI->getPhysicalRegisterRegClass(SrcReg, Node->getValueType(ResNo));
// Figure out the register class to create for the destreg.
if (VRBase) {
DstRC = MRI.getRegClass(VRBase);
} else {
DstRC = TLI->getRegClassFor(Node->getValueType(ResNo));
}
// 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);
TII->copyRegToReg(*BB, BB->end(), VRBase, SrcReg, DstRC, SrcRC);
}
SDValue Op(Node, ResNo);
if (IsClone)
VRBaseMap.erase(Op);
bool isNew = VRBaseMap.insert(std::make_pair(Op, VRBase)).second;
isNew = 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 ScheduleDAG::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 ScheduleDAG::CreateVirtualRegisters(SDNode *Node, MachineInstr *MI,
const TargetInstrDesc &II,
DenseMap<SDValue, unsigned> &VRBaseMap) {
assert(Node->getMachineOpcode() != TargetInstrInfo::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, use the CopyToReg'd destination register instead of creating
// a new vreg.
unsigned VRBase = 0;
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)) {
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) {
const TargetRegisterClass *RC = getInstrOperandRegClass(TRI, TII, II, i);
assert(RC && "Isn't a register operand!");
VRBase = MRI.createVirtualRegister(RC);
MI->addOperand(MachineOperand::CreateReg(VRBase, true));
}
SDValue Op(Node, i);
bool isNew = VRBaseMap.insert(std::make_pair(Op, VRBase)).second;
isNew = 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 ScheduleDAG::getVR(SDValue Op,
DenseMap<SDValue, unsigned> &VRBaseMap) {
if (Op.isMachineOpcode() &&
Op.getMachineOpcode() == TargetInstrInfo::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 TargetInstrDesc
// does not include operand register class info.
if (!VReg) {
const TargetRegisterClass *RC = TLI->getRegClassFor(Op.getValueType());
VReg = MRI.createVirtualRegister(RC);
}
BuildMI(BB, TII->get(TargetInstrInfo::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;
}
/// 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. IIOpNum and II are used for
/// assertions only.
void ScheduleDAG::AddOperand(MachineInstr *MI, SDValue Op,
unsigned IIOpNum,
const TargetInstrDesc *II,
DenseMap<SDValue, unsigned> &VRBaseMap) {
if (Op.isMachineOpcode()) {
// Note that this case is redundant with the final else block, but we
// include it because it is the most common and it makes the logic
// simpler here.
assert(Op.getValueType() != MVT::Other &&
Op.getValueType() != MVT::Flag &&
"Chain and flag operands should occur at end of operand list!");
// Get/emit the operand.
unsigned VReg = getVR(Op, VRBaseMap);
const TargetInstrDesc &TID = MI->getDesc();
bool isOptDef = IIOpNum < TID.getNumOperands() &&
TID.OpInfo[IIOpNum].isOptionalDef();
MI->addOperand(MachineOperand::CreateReg(VReg, isOptDef));
// Verify that it is right.
assert(TargetRegisterInfo::isVirtualRegister(VReg) && "Not a vreg?");
#ifndef NDEBUG
if (II) {
// There may be no register class for this operand if it is a variadic
// argument (RC will be NULL in this case). In this case, we just assume
// the regclass is ok.
const TargetRegisterClass *RC =
getInstrOperandRegClass(TRI, TII, *II, IIOpNum);
assert((RC || II->isVariadic()) && "Expected reg class info!");
const TargetRegisterClass *VRC = MRI.getRegClass(VReg);
if (RC && VRC != RC) {
cerr << "Register class of operand and regclass of use don't agree!\n";
cerr << "Operand = " << IIOpNum << "\n";
cerr << "Op->Val = "; Op.getNode()->dump(&DAG); cerr << "\n";
cerr << "MI = "; MI->print(cerr);
cerr << "VReg = " << VReg << "\n";
cerr << "VReg RegClass size = " << VRC->getSize()
<< ", align = " << VRC->getAlignment() << "\n";
cerr << "Expected RegClass size = " << RC->getSize()
<< ", align = " << RC->getAlignment() << "\n";
cerr << "Fatal error, aborting.\n";
abort();
}
}
#endif
} else if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op)) {
MI->addOperand(MachineOperand::CreateImm(C->getValue()));
} else if (ConstantFPSDNode *F = dyn_cast<ConstantFPSDNode>(Op)) {
ConstantFP *CFP = ConstantFP::get(F->getValueAPF());
MI->addOperand(MachineOperand::CreateFPImm(CFP));
} else if (RegisterSDNode *R = dyn_cast<RegisterSDNode>(Op)) {
MI->addOperand(MachineOperand::CreateReg(R->getReg(), false));
} else if (GlobalAddressSDNode *TGA = dyn_cast<GlobalAddressSDNode>(Op)) {
MI->addOperand(MachineOperand::CreateGA(TGA->getGlobal(),TGA->getOffset()));
} else if (BasicBlockSDNode *BB = dyn_cast<BasicBlockSDNode>(Op)) {
MI->addOperand(MachineOperand::CreateMBB(BB->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()));
} else if (ConstantPoolSDNode *CP = dyn_cast<ConstantPoolSDNode>(Op)) {
int Offset = CP->getOffset();
unsigned Align = CP->getAlignment();
const Type *Type = CP->getType();
// MachineConstantPool wants an explicit alignment.
if (Align == 0) {
Align = TM.getTargetData()->getPreferredTypeAlignmentShift(Type);
if (Align == 0) {
// Alignment of vector types. FIXME!
Align = TM.getTargetData()->getABITypeSize(Type);
Align = Log2_64(Align);
}
}
unsigned Idx;
if (CP->isMachineConstantPoolEntry())
Idx = ConstPool->getConstantPoolIndex(CP->getMachineCPVal(), Align);
else
Idx = ConstPool->getConstantPoolIndex(CP->getConstVal(), Align);
MI->addOperand(MachineOperand::CreateCPI(Idx, Offset));
} else if (ExternalSymbolSDNode *ES = dyn_cast<ExternalSymbolSDNode>(Op)) {
MI->addOperand(MachineOperand::CreateES(ES->getSymbol()));
} else {
assert(Op.getValueType() != MVT::Other &&
Op.getValueType() != MVT::Flag &&
"Chain and flag operands should occur at end of operand list!");
unsigned VReg = getVR(Op, VRBaseMap);
MI->addOperand(MachineOperand::CreateReg(VReg, false));
// Verify that it is right. Note that the reg class of the physreg and the
// vreg don't necessarily need to match, but the target copy insertion has
// to be able to handle it. This handles things like copies from ST(0) to
// an FP vreg on x86.
assert(TargetRegisterInfo::isVirtualRegister(VReg) && "Not a vreg?");
if (II && !II->isVariadic()) {
assert(getInstrOperandRegClass(TRI, TII, *II, IIOpNum) &&
"Don't have operand info for this instruction!");
}
}
}
void ScheduleDAG::AddMemOperand(MachineInstr *MI, const MachineMemOperand &MO) {
MI->addMemOperand(*MF, MO);
}
/// getSubRegisterRegClass - Returns the register class of specified register
/// class' "SubIdx"'th sub-register class.
static const TargetRegisterClass*
getSubRegisterRegClass(const TargetRegisterClass *TRC, unsigned SubIdx) {
// Pick the register class of the subregister
TargetRegisterInfo::regclass_iterator I =
TRC->subregclasses_begin() + SubIdx-1;
assert(I < TRC->subregclasses_end() &&
"Invalid subregister index for register class");
return *I;
}
/// getSuperRegisterRegClass - Returns the register class of a superreg A whose
/// "SubIdx"'th sub-register class is the specified register class and whose
/// type matches the specified type.
static const TargetRegisterClass*
getSuperRegisterRegClass(const TargetRegisterClass *TRC,
unsigned SubIdx, MVT VT) {
// Pick the register class of the superegister for this type
for (TargetRegisterInfo::regclass_iterator I = TRC->superregclasses_begin(),
E = TRC->superregclasses_end(); I != E; ++I)
if ((*I)->hasType(VT) && getSubRegisterRegClass(*I, SubIdx) == TRC)
return *I;
assert(false && "Couldn't find the register class");
return 0;
}
/// EmitSubregNode - Generate machine code for subreg nodes.
///
void ScheduleDAG::EmitSubregNode(SDNode *Node,
DenseMap<SDValue, unsigned> &VRBaseMap) {
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 == TargetInstrInfo::EXTRACT_SUBREG) {
unsigned SubIdx = cast<ConstantSDNode>(Node->getOperand(1))->getValue();
// Create the extract_subreg machine instruction.
MachineInstr *MI = BuildMI(*MF, TII->get(TargetInstrInfo::EXTRACT_SUBREG));
// Figure out the register class to create for the destreg.
unsigned VReg = getVR(Node->getOperand(0), VRBaseMap);
const TargetRegisterClass *TRC = MRI.getRegClass(VReg);
const TargetRegisterClass *SRC = getSubRegisterRegClass(TRC, SubIdx);
if (VRBase) {
// Grab the destination register
#ifndef NDEBUG
const TargetRegisterClass *DRC = MRI.getRegClass(VRBase);
assert(SRC && DRC && SRC == DRC &&
"Source subregister and destination must have the same class");
#endif
} else {
// Create the reg
assert(SRC && "Couldn't find source register class");
VRBase = MRI.createVirtualRegister(SRC);
}
// Add def, source, and subreg index
MI->addOperand(MachineOperand::CreateReg(VRBase, true));
AddOperand(MI, Node->getOperand(0), 0, 0, VRBaseMap);
MI->addOperand(MachineOperand::CreateImm(SubIdx));
BB->push_back(MI);
} else if (Opc == TargetInstrInfo::INSERT_SUBREG ||
Opc == TargetInstrInfo::SUBREG_TO_REG) {
SDValue N0 = Node->getOperand(0);
SDValue N1 = Node->getOperand(1);
SDValue N2 = Node->getOperand(2);
unsigned SubReg = getVR(N1, VRBaseMap);
unsigned SubIdx = cast<ConstantSDNode>(N2)->getValue();
// Figure out the register class to create for the destreg.
const TargetRegisterClass *TRC = 0;
if (VRBase) {
TRC = MRI.getRegClass(VRBase);
} else {
TRC = getSuperRegisterRegClass(MRI.getRegClass(SubReg), SubIdx,
Node->getValueType(0));
assert(TRC && "Couldn't determine register class for insert_subreg");
VRBase = MRI.createVirtualRegister(TRC); // Create the reg
}
// Create the insert_subreg or subreg_to_reg machine instruction.
MachineInstr *MI = BuildMI(*MF, 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 == TargetInstrInfo::SUBREG_TO_REG) {
const ConstantSDNode *SD = cast<ConstantSDNode>(N0);
MI->addOperand(MachineOperand::CreateImm(SD->getValue()));
} else
AddOperand(MI, N0, 0, 0, VRBaseMap);
// Add the subregster being inserted
AddOperand(MI, N1, 0, 0, VRBaseMap);
MI->addOperand(MachineOperand::CreateImm(SubIdx));
BB->push_back(MI);
} else
assert(0 && "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;
isNew = isNew; // Silence compiler warning.
assert(isNew && "Node emitted out of order - early");
}
/// EmitNode - Generate machine code for an node and needed dependencies.
///
void ScheduleDAG::EmitNode(SDNode *Node, bool IsClone,
DenseMap<SDValue, unsigned> &VRBaseMap) {
// If machine instruction
if (Node->isMachineOpcode()) {
unsigned Opc = Node->getMachineOpcode();
// Handle subreg insert/extract specially
if (Opc == TargetInstrInfo::EXTRACT_SUBREG ||
Opc == TargetInstrInfo::INSERT_SUBREG ||
Opc == TargetInstrInfo::SUBREG_TO_REG) {
EmitSubregNode(Node, VRBaseMap);
return;
}
if (Opc == TargetInstrInfo::IMPLICIT_DEF)
// We want a unique VR for each IMPLICIT_DEF use.
return;
const TargetInstrDesc &II = TII->get(Opc);
unsigned NumResults = CountResults(Node);
unsigned NodeOperands = CountOperands(Node);
unsigned MemOperandsEnd = ComputeMemOperandsEnd(Node);
bool HasPhysRegOuts = (NumResults > II.getNumDefs()) &&
II.getImplicitDefs() != 0;
#ifndef NDEBUG
unsigned NumMIOperands = NodeOperands + NumResults;
assert((II.getNumOperands() == NumMIOperands ||
HasPhysRegOuts || II.isVariadic()) &&
"#operands for dag node doesn't match .td file!");
#endif
// Create the new machine instruction.
MachineInstr *MI = BuildMI(*MF, II);
// Add result register values for things that are defined by this
// instruction.
if (NumResults)
CreateVirtualRegisters(Node, MI, II, VRBaseMap);
// Emit all of the actual operands of this instruction, adding them to the
// instruction as appropriate.
for (unsigned i = 0; i != NodeOperands; ++i)
AddOperand(MI, Node->getOperand(i), i+II.getNumDefs(), &II, VRBaseMap);
// Emit all of the memory operands of this instruction
for (unsigned i = NodeOperands; i != MemOperandsEnd; ++i)
AddMemOperand(MI, cast<MemOperandSDNode>(Node->getOperand(i))->MO);
// Commute node if it has been determined to be profitable.
if (CommuteSet.count(Node)) {
MachineInstr *NewMI = TII->commuteInstruction(MI);
if (NewMI == 0)
DOUT << "Sched: COMMUTING FAILED!\n";
else {
DOUT << "Sched: COMMUTED TO: " << *NewMI;
if (MI != NewMI) {
MF->DeleteMachineInstr(MI);
MI = NewMI;
}
++NumCommutes;
}
}
if (II.usesCustomDAGSchedInsertionHook())
// Insert this instruction into the basic block using a target
// specific inserter which may returns a new basic block.
BB = TLI->EmitInstrWithCustomInserter(MI, BB);
else
BB->push_back(MI);
// Additional results must be an physical register def.
if (HasPhysRegOuts) {
for (unsigned i = II.getNumDefs(); i < NumResults; ++i) {
unsigned Reg = II.getImplicitDefs()[i - II.getNumDefs()];
if (Node->hasAnyUseOfValue(i))
EmitCopyFromReg(Node, i, IsClone, Reg, VRBaseMap);
}
}
return;
}
switch (Node->getOpcode()) {
default:
#ifndef NDEBUG
Node->dump(&DAG);
#endif
assert(0 && "This target-independent node should have been selected!");
break;
case ISD::EntryToken:
assert(0 && "EntryToken should have been excluded from the schedule!");
break;
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;
const TargetRegisterClass *SrcTRC = 0, *DstTRC = 0;
// Get the register classes of the src/dst.
if (TargetRegisterInfo::isVirtualRegister(SrcReg))
SrcTRC = MRI.getRegClass(SrcReg);
else
SrcTRC = TRI->getPhysicalRegisterRegClass(SrcReg,SrcVal.getValueType());
if (TargetRegisterInfo::isVirtualRegister(DestReg))
DstTRC = MRI.getRegClass(DestReg);
else
DstTRC = TRI->getPhysicalRegisterRegClass(DestReg,
Node->getOperand(1).getValueType());
TII->copyRegToReg(*BB, BB->end(), DestReg, SrcReg, DstTRC, SrcTRC);
break;
}
case ISD::CopyFromReg: {
unsigned SrcReg = cast<RegisterSDNode>(Node->getOperand(1))->getReg();
EmitCopyFromReg(Node, 0, IsClone, SrcReg, VRBaseMap);
break;
}
case ISD::INLINEASM: {
unsigned NumOps = Node->getNumOperands();
if (Node->getOperand(NumOps-1).getValueType() == MVT::Flag)
--NumOps; // Ignore the flag operand.
// Create the inline asm machine instruction.
MachineInstr *MI = BuildMI(*MF, TII->get(TargetInstrInfo::INLINEASM));
// Add the asm string as an external symbol operand.
const char *AsmStr =
cast<ExternalSymbolSDNode>(Node->getOperand(1))->getSymbol();
MI->addOperand(MachineOperand::CreateES(AsmStr));
// Add all of the operand registers to the instruction.
for (unsigned i = 2; i != NumOps;) {
unsigned Flags = cast<ConstantSDNode>(Node->getOperand(i))->getValue();
unsigned NumVals = Flags >> 3;
MI->addOperand(MachineOperand::CreateImm(Flags));
++i; // Skip the ID value.
switch (Flags & 7) {
default: assert(0 && "Bad flags!");
case 2: // Def of register.
for (; NumVals; --NumVals, ++i) {
unsigned Reg = cast<RegisterSDNode>(Node->getOperand(i))->getReg();
MI->addOperand(MachineOperand::CreateReg(Reg, true));
}
break;
case 1: // Use of register.
case 3: // Immediate.
case 4: // 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);
break;
}
}
BB->push_back(MI);
break;
}
}
}
void ScheduleDAG::EmitNoop() {
TII->insertNoop(*BB, BB->end());
}
void ScheduleDAG::EmitCrossRCCopy(SUnit *SU,
DenseMap<SUnit*, unsigned> &VRBaseMap) {
for (SUnit::const_pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
I != E; ++I) {
if (I->isCtrl) continue; // ignore chain preds
if (!I->Dep->Node) {
// Copy to physical register.
DenseMap<SUnit*, unsigned>::iterator VRI = VRBaseMap.find(I->Dep);
assert(VRI != VRBaseMap.end() && "Node emitted out of order - late");
// Find the destination physical register.
unsigned Reg = 0;
for (SUnit::const_succ_iterator II = SU->Succs.begin(),
EE = SU->Succs.end(); II != EE; ++II) {
if (I->Reg) {
Reg = I->Reg;
break;
}
}
assert(I->Reg && "Unknown physical register!");
TII->copyRegToReg(*BB, BB->end(), Reg, VRI->second,
SU->CopyDstRC, SU->CopySrcRC);
} else {
// Copy from physical register.
assert(I->Reg && "Unknown physical register!");
unsigned VRBase = MRI.createVirtualRegister(SU->CopyDstRC);
bool isNew = VRBaseMap.insert(std::make_pair(SU, VRBase)).second;
isNew = isNew; // Silence compiler warning.
assert(isNew && "Node emitted out of order - early");
TII->copyRegToReg(*BB, BB->end(), VRBase, I->Reg,
SU->CopyDstRC, SU->CopySrcRC);
}
break;
}
}
/// EmitSchedule - Emit the machine code in scheduled order.
MachineBasicBlock *ScheduleDAG::EmitSchedule() {
DenseMap<SDValue, unsigned> VRBaseMap;
DenseMap<SUnit*, unsigned> CopyVRBaseMap;
for (unsigned i = 0, e = Sequence.size(); i != e; i++) {
SUnit *SU = Sequence[i];
if (!SU) {
// Null SUnit* is a noop.
EmitNoop();
continue;
}
for (unsigned j = 0, ee = SU->FlaggedNodes.size(); j != ee; ++j)
EmitNode(SU->FlaggedNodes[j], SU->OrigNode != SU, VRBaseMap);
if (!SU->Node)
EmitCrossRCCopy(SU, CopyVRBaseMap);
else
EmitNode(SU->Node, SU->OrigNode != SU, VRBaseMap);
}
return BB;
}
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