MSP430ISelLowering.cpp revision 8d1ffbd1adad453fe330be4951400bfd25fab666 
1//===-- MSP430ISelLowering.cpp - MSP430 DAG Lowering Implementation  ------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file implements the MSP430TargetLowering class.
11//
12//===----------------------------------------------------------------------===//
13
14#define DEBUG_TYPE "msp430-lower"
15
16#include "MSP430ISelLowering.h"
17#include "MSP430.h"
18#include "MSP430MachineFunctionInfo.h"
19#include "MSP430TargetMachine.h"
20#include "MSP430Subtarget.h"
21#include "llvm/DerivedTypes.h"
22#include "llvm/Function.h"
23#include "llvm/Intrinsics.h"
24#include "llvm/CallingConv.h"
25#include "llvm/GlobalVariable.h"
26#include "llvm/GlobalAlias.h"
27#include "llvm/CodeGen/CallingConvLower.h"
28#include "llvm/CodeGen/MachineFrameInfo.h"
29#include "llvm/CodeGen/MachineFunction.h"
30#include "llvm/CodeGen/MachineInstrBuilder.h"
31#include "llvm/CodeGen/MachineRegisterInfo.h"
32#include "llvm/CodeGen/PseudoSourceValue.h"
33#include "llvm/CodeGen/SelectionDAGISel.h"
34#include "llvm/CodeGen/ValueTypes.h"
35#include "llvm/Target/TargetLoweringObjectFile.h"
36#include "llvm/Support/CommandLine.h"
37#include "llvm/Support/Debug.h"
38#include "llvm/Support/ErrorHandling.h"
39#include "llvm/Support/raw_ostream.h"
40#include "llvm/ADT/VectorExtras.h"
41using namespace llvm;
42
43typedef enum {
44  NoHWMult,
45  HWMultIntr,
46  HWMultNoIntr
47} HWMultUseMode;
48
49static cl::opt<HWMultUseMode>
50HWMultMode("msp430-hwmult-mode",
51           cl::desc("Hardware multiplier use mode"),
52           cl::init(HWMultNoIntr),
53           cl::values(
54             clEnumValN(NoHWMult, "no",
55                "Do not use hardware multiplier"),
56             clEnumValN(HWMultIntr, "interrupts",
57                "Assume hardware multiplier can be used inside interrupts"),
58             clEnumValN(HWMultNoIntr, "use",
59                "Assume hardware multiplier cannot be used inside interrupts"),
60             clEnumValEnd));
61
62MSP430TargetLowering::MSP430TargetLowering(MSP430TargetMachine &tm) :
63  TargetLowering(tm, new TargetLoweringObjectFileELF()),
64  Subtarget(*tm.getSubtargetImpl()), TM(tm) {
65
66  TD = getTargetData();
67
68  // Set up the register classes.
69  addRegisterClass(MVT::i8,  MSP430::GR8RegisterClass);
70  addRegisterClass(MVT::i16, MSP430::GR16RegisterClass);
71
72  // Compute derived properties from the register classes
73  computeRegisterProperties();
74
75  // Provide all sorts of operation actions
76
77  // Division is expensive
78  setIntDivIsCheap(false);
79
80  // Even if we have only 1 bit shift here, we can perform
81  // shifts of the whole bitwidth 1 bit per step.
82  setShiftAmountType(MVT::i8);
83
84  setStackPointerRegisterToSaveRestore(MSP430::SPW);
85  setBooleanContents(ZeroOrOneBooleanContent);
86  setSchedulingPreference(SchedulingForLatency);
87
88  // We have post-incremented loads / stores.
89  setIndexedLoadAction(ISD::POST_INC, MVT::i8, Legal);
90  setIndexedLoadAction(ISD::POST_INC, MVT::i16, Legal);
91
92  setLoadExtAction(ISD::EXTLOAD,  MVT::i1,  Promote);
93  setLoadExtAction(ISD::SEXTLOAD, MVT::i1,  Promote);
94  setLoadExtAction(ISD::ZEXTLOAD, MVT::i1,  Promote);
95  setLoadExtAction(ISD::SEXTLOAD, MVT::i8,  Expand);
96  setLoadExtAction(ISD::SEXTLOAD, MVT::i16, Expand);
97
98  // We don't have any truncstores
99  setTruncStoreAction(MVT::i16, MVT::i8, Expand);
100
101  setOperationAction(ISD::SRA,              MVT::i8,    Custom);
102  setOperationAction(ISD::SHL,              MVT::i8,    Custom);
103  setOperationAction(ISD::SRL,              MVT::i8,    Custom);
104  setOperationAction(ISD::SRA,              MVT::i16,   Custom);
105  setOperationAction(ISD::SHL,              MVT::i16,   Custom);
106  setOperationAction(ISD::SRL,              MVT::i16,   Custom);
107  setOperationAction(ISD::ROTL,             MVT::i8,    Expand);
108  setOperationAction(ISD::ROTR,             MVT::i8,    Expand);
109  setOperationAction(ISD::ROTL,             MVT::i16,   Expand);
110  setOperationAction(ISD::ROTR,             MVT::i16,   Expand);
111  setOperationAction(ISD::GlobalAddress,    MVT::i16,   Custom);
112  setOperationAction(ISD::ExternalSymbol,   MVT::i16,   Custom);
113  setOperationAction(ISD::BR_JT,            MVT::Other, Expand);
114  setOperationAction(ISD::BRIND,            MVT::Other, Expand);
115  setOperationAction(ISD::BR_CC,            MVT::i8,    Custom);
116  setOperationAction(ISD::BR_CC,            MVT::i16,   Custom);
117  setOperationAction(ISD::BRCOND,           MVT::Other, Expand);
118  setOperationAction(ISD::SETCC,            MVT::i8,    Custom);
119  setOperationAction(ISD::SETCC,            MVT::i16,   Custom);
120  setOperationAction(ISD::SELECT,           MVT::i8,    Expand);
121  setOperationAction(ISD::SELECT,           MVT::i16,   Expand);
122  setOperationAction(ISD::SELECT_CC,        MVT::i8,    Custom);
123  setOperationAction(ISD::SELECT_CC,        MVT::i16,   Custom);
124  setOperationAction(ISD::SIGN_EXTEND,      MVT::i16,   Custom);
125  setOperationAction(ISD::DYNAMIC_STACKALLOC, MVT::i8, Expand);
126  setOperationAction(ISD::DYNAMIC_STACKALLOC, MVT::i16, Expand);
127
128  setOperationAction(ISD::CTTZ,             MVT::i8,    Expand);
129  setOperationAction(ISD::CTTZ,             MVT::i16,   Expand);
130  setOperationAction(ISD::CTLZ,             MVT::i8,    Expand);
131  setOperationAction(ISD::CTLZ,             MVT::i16,   Expand);
132  setOperationAction(ISD::CTPOP,            MVT::i8,    Expand);
133  setOperationAction(ISD::CTPOP,            MVT::i16,   Expand);
134
135  setOperationAction(ISD::SHL_PARTS,        MVT::i8,    Expand);
136  setOperationAction(ISD::SHL_PARTS,        MVT::i16,   Expand);
137  setOperationAction(ISD::SRL_PARTS,        MVT::i8,    Expand);
138  setOperationAction(ISD::SRL_PARTS,        MVT::i16,   Expand);
139  setOperationAction(ISD::SRA_PARTS,        MVT::i8,    Expand);
140  setOperationAction(ISD::SRA_PARTS,        MVT::i16,   Expand);
141
142  setOperationAction(ISD::SIGN_EXTEND_INREG, MVT::i1,   Expand);
143
144  // FIXME: Implement efficiently multiplication by a constant
145  setOperationAction(ISD::MUL,              MVT::i8,    Expand);
146  setOperationAction(ISD::MULHS,            MVT::i8,    Expand);
147  setOperationAction(ISD::MULHU,            MVT::i8,    Expand);
148  setOperationAction(ISD::SMUL_LOHI,        MVT::i8,    Expand);
149  setOperationAction(ISD::UMUL_LOHI,        MVT::i8,    Expand);
150  setOperationAction(ISD::MUL,              MVT::i16,   Expand);
151  setOperationAction(ISD::MULHS,            MVT::i16,   Expand);
152  setOperationAction(ISD::MULHU,            MVT::i16,   Expand);
153  setOperationAction(ISD::SMUL_LOHI,        MVT::i16,   Expand);
154  setOperationAction(ISD::UMUL_LOHI,        MVT::i16,   Expand);
155
156  setOperationAction(ISD::UDIV,             MVT::i8,    Expand);
157  setOperationAction(ISD::UDIVREM,          MVT::i8,    Expand);
158  setOperationAction(ISD::UREM,             MVT::i8,    Expand);
159  setOperationAction(ISD::SDIV,             MVT::i8,    Expand);
160  setOperationAction(ISD::SDIVREM,          MVT::i8,    Expand);
161  setOperationAction(ISD::SREM,             MVT::i8,    Expand);
162  setOperationAction(ISD::UDIV,             MVT::i16,   Expand);
163  setOperationAction(ISD::UDIVREM,          MVT::i16,   Expand);
164  setOperationAction(ISD::UREM,             MVT::i16,   Expand);
165  setOperationAction(ISD::SDIV,             MVT::i16,   Expand);
166  setOperationAction(ISD::SDIVREM,          MVT::i16,   Expand);
167  setOperationAction(ISD::SREM,             MVT::i16,   Expand);
168
169  // Libcalls names.
170  if (HWMultMode == HWMultIntr) {
171    setLibcallName(RTLIB::MUL_I8,  "__mulqi3hw");
172    setLibcallName(RTLIB::MUL_I16, "__mulhi3hw");
173  } else if (HWMultMode == HWMultNoIntr) {
174    setLibcallName(RTLIB::MUL_I8,  "__mulqi3hw_noint");
175    setLibcallName(RTLIB::MUL_I16, "__mulhi3hw_noint");
176  }
177}
178
179SDValue MSP430TargetLowering::LowerOperation(SDValue Op, SelectionDAG &DAG) {
180  switch (Op.getOpcode()) {
181  case ISD::SHL: // FALLTHROUGH
182  case ISD::SRL:
183  case ISD::SRA:              return LowerShifts(Op, DAG);
184  case ISD::GlobalAddress:    return LowerGlobalAddress(Op, DAG);
185  case ISD::ExternalSymbol:   return LowerExternalSymbol(Op, DAG);
186  case ISD::SETCC:            return LowerSETCC(Op, DAG);
187  case ISD::BR_CC:            return LowerBR_CC(Op, DAG);
188  case ISD::SELECT_CC:        return LowerSELECT_CC(Op, DAG);
189  case ISD::SIGN_EXTEND:      return LowerSIGN_EXTEND(Op, DAG);
190  case ISD::RETURNADDR:       return LowerRETURNADDR(Op, DAG);
191  case ISD::FRAMEADDR:        return LowerFRAMEADDR(Op, DAG);
192  default:
193    llvm_unreachable("unimplemented operand");
194    return SDValue();
195  }
196}
197
198/// getFunctionAlignment - Return the Log2 alignment of this function.
199unsigned MSP430TargetLowering::getFunctionAlignment(const Function *F) const {
200  return F->hasFnAttr(Attribute::OptimizeForSize) ? 1 : 2;
201}
202
203//===----------------------------------------------------------------------===//
204//                       MSP430 Inline Assembly Support
205//===----------------------------------------------------------------------===//
206
207/// getConstraintType - Given a constraint letter, return the type of
208/// constraint it is for this target.
209TargetLowering::ConstraintType
210MSP430TargetLowering::getConstraintType(const std::string &Constraint) const {
211  if (Constraint.size() == 1) {
212    switch (Constraint[0]) {
213    case 'r':
214      return C_RegisterClass;
215    default:
216      break;
217    }
218  }
219  return TargetLowering::getConstraintType(Constraint);
220}
221
222std::pair<unsigned, const TargetRegisterClass*>
223MSP430TargetLowering::
224getRegForInlineAsmConstraint(const std::string &Constraint,
225                             EVT VT) const {
226  if (Constraint.size() == 1) {
227    // GCC Constraint Letters
228    switch (Constraint[0]) {
229    default: break;
230    case 'r':   // GENERAL_REGS
231      if (VT == MVT::i8)
232        return std::make_pair(0U, MSP430::GR8RegisterClass);
233
234      return std::make_pair(0U, MSP430::GR16RegisterClass);
235    }
236  }
237
238  return TargetLowering::getRegForInlineAsmConstraint(Constraint, VT);
239}
240
241//===----------------------------------------------------------------------===//
242//                      Calling Convention Implementation
243//===----------------------------------------------------------------------===//
244
245#include "MSP430GenCallingConv.inc"
246
247SDValue
248MSP430TargetLowering::LowerFormalArguments(SDValue Chain,
249                                           CallingConv::ID CallConv,
250                                           bool isVarArg,
251                                           const SmallVectorImpl<ISD::InputArg>
252                                             &Ins,
253                                           DebugLoc dl,
254                                           SelectionDAG &DAG,
255                                           SmallVectorImpl<SDValue> &InVals) {
256
257  switch (CallConv) {
258  default:
259    llvm_unreachable("Unsupported calling convention");
260  case CallingConv::C:
261  case CallingConv::Fast:
262    return LowerCCCArguments(Chain, CallConv, isVarArg, Ins, dl, DAG, InVals);
263  case CallingConv::MSP430_INTR:
264   if (Ins.empty())
265     return Chain;
266   else {
267    llvm_report_error("ISRs cannot have arguments");
268    return SDValue();
269   }
270  }
271}
272
273SDValue
274MSP430TargetLowering::LowerCall(SDValue Chain, SDValue Callee,
275                                CallingConv::ID CallConv, bool isVarArg,
276                                bool isTailCall,
277                                const SmallVectorImpl<ISD::OutputArg> &Outs,
278                                const SmallVectorImpl<ISD::InputArg> &Ins,
279                                DebugLoc dl, SelectionDAG &DAG,
280                                SmallVectorImpl<SDValue> &InVals) {
281
282  switch (CallConv) {
283  default:
284    llvm_unreachable("Unsupported calling convention");
285  case CallingConv::Fast:
286  case CallingConv::C:
287    return LowerCCCCallTo(Chain, Callee, CallConv, isVarArg, isTailCall,
288                          Outs, Ins, dl, DAG, InVals);
289  case CallingConv::MSP430_INTR:
290    llvm_report_error("ISRs cannot be called directly");
291    return SDValue();
292  }
293}
294
295/// LowerCCCArguments - transform physical registers into virtual registers and
296/// generate load operations for arguments places on the stack.
297// FIXME: struct return stuff
298// FIXME: varargs
299SDValue
300MSP430TargetLowering::LowerCCCArguments(SDValue Chain,
301                                        CallingConv::ID CallConv,
302                                        bool isVarArg,
303                                        const SmallVectorImpl<ISD::InputArg>
304                                          &Ins,
305                                        DebugLoc dl,
306                                        SelectionDAG &DAG,
307                                        SmallVectorImpl<SDValue> &InVals) {
308  MachineFunction &MF = DAG.getMachineFunction();
309  MachineFrameInfo *MFI = MF.getFrameInfo();
310  MachineRegisterInfo &RegInfo = MF.getRegInfo();
311
312  // Assign locations to all of the incoming arguments.
313  SmallVector<CCValAssign, 16> ArgLocs;
314  CCState CCInfo(CallConv, isVarArg, getTargetMachine(),
315                 ArgLocs, *DAG.getContext());
316  CCInfo.AnalyzeFormalArguments(Ins, CC_MSP430);
317
318  assert(!isVarArg && "Varargs not supported yet");
319
320  for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) {
321    CCValAssign &VA = ArgLocs[i];
322    if (VA.isRegLoc()) {
323      // Arguments passed in registers
324      EVT RegVT = VA.getLocVT();
325      switch (RegVT.getSimpleVT().SimpleTy) {
326      default:
327        {
328#ifndef NDEBUG
329          errs() << "LowerFormalArguments Unhandled argument type: "
330               << RegVT.getSimpleVT().SimpleTy << "\n";
331#endif
332          llvm_unreachable(0);
333        }
334      case MVT::i16:
335        unsigned VReg =
336          RegInfo.createVirtualRegister(MSP430::GR16RegisterClass);
337        RegInfo.addLiveIn(VA.getLocReg(), VReg);
338        SDValue ArgValue = DAG.getCopyFromReg(Chain, dl, VReg, RegVT);
339
340        // If this is an 8-bit value, it is really passed promoted to 16
341        // bits. Insert an assert[sz]ext to capture this, then truncate to the
342        // right size.
343        if (VA.getLocInfo() == CCValAssign::SExt)
344          ArgValue = DAG.getNode(ISD::AssertSext, dl, RegVT, ArgValue,
345                                 DAG.getValueType(VA.getValVT()));
346        else if (VA.getLocInfo() == CCValAssign::ZExt)
347          ArgValue = DAG.getNode(ISD::AssertZext, dl, RegVT, ArgValue,
348                                 DAG.getValueType(VA.getValVT()));
349
350        if (VA.getLocInfo() != CCValAssign::Full)
351          ArgValue = DAG.getNode(ISD::TRUNCATE, dl, VA.getValVT(), ArgValue);
352
353        InVals.push_back(ArgValue);
354      }
355    } else {
356      // Sanity check
357      assert(VA.isMemLoc());
358      // Load the argument to a virtual register
359      unsigned ObjSize = VA.getLocVT().getSizeInBits()/8;
360      if (ObjSize > 2) {
361        errs() << "LowerFormalArguments Unhandled argument type: "
362             << VA.getLocVT().getSimpleVT().SimpleTy
363             << "\n";
364      }
365      // Create the frame index object for this incoming parameter...
366      int FI = MFI->CreateFixedObject(ObjSize, VA.getLocMemOffset(), true, false);
367
368      // Create the SelectionDAG nodes corresponding to a load
369      //from this parameter
370      SDValue FIN = DAG.getFrameIndex(FI, MVT::i16);
371      InVals.push_back(DAG.getLoad(VA.getLocVT(), dl, Chain, FIN,
372                                   PseudoSourceValue::getFixedStack(FI), 0));
373    }
374  }
375
376  return Chain;
377}
378
379SDValue
380MSP430TargetLowering::LowerReturn(SDValue Chain,
381                                  CallingConv::ID CallConv, bool isVarArg,
382                                  const SmallVectorImpl<ISD::OutputArg> &Outs,
383                                  DebugLoc dl, SelectionDAG &DAG) {
384
385  // CCValAssign - represent the assignment of the return value to a location
386  SmallVector<CCValAssign, 16> RVLocs;
387
388  // ISRs cannot return any value.
389  if (CallConv == CallingConv::MSP430_INTR && !Outs.empty()) {
390    llvm_report_error("ISRs cannot return any value");
391    return SDValue();
392  }
393
394  // CCState - Info about the registers and stack slot.
395  CCState CCInfo(CallConv, isVarArg, getTargetMachine(),
396                 RVLocs, *DAG.getContext());
397
398  // Analize return values.
399  CCInfo.AnalyzeReturn(Outs, RetCC_MSP430);
400
401  // If this is the first return lowered for this function, add the regs to the
402  // liveout set for the function.
403  if (DAG.getMachineFunction().getRegInfo().liveout_empty()) {
404    for (unsigned i = 0; i != RVLocs.size(); ++i)
405      if (RVLocs[i].isRegLoc())
406        DAG.getMachineFunction().getRegInfo().addLiveOut(RVLocs[i].getLocReg());
407  }
408
409  SDValue Flag;
410
411  // Copy the result values into the output registers.
412  for (unsigned i = 0; i != RVLocs.size(); ++i) {
413    CCValAssign &VA = RVLocs[i];
414    assert(VA.isRegLoc() && "Can only return in registers!");
415
416    Chain = DAG.getCopyToReg(Chain, dl, VA.getLocReg(),
417                             Outs[i].Val, Flag);
418
419    // Guarantee that all emitted copies are stuck together,
420    // avoiding something bad.
421    Flag = Chain.getValue(1);
422  }
423
424  unsigned Opc = (CallConv == CallingConv::MSP430_INTR ?
425                  MSP430ISD::RETI_FLAG : MSP430ISD::RET_FLAG);
426
427  if (Flag.getNode())
428    return DAG.getNode(Opc, dl, MVT::Other, Chain, Flag);
429
430  // Return Void
431  return DAG.getNode(Opc, dl, MVT::Other, Chain);
432}
433
434/// LowerCCCCallTo - functions arguments are copied from virtual regs to
435/// (physical regs)/(stack frame), CALLSEQ_START and CALLSEQ_END are emitted.
436/// TODO: sret.
437SDValue
438MSP430TargetLowering::LowerCCCCallTo(SDValue Chain, SDValue Callee,
439                                     CallingConv::ID CallConv, bool isVarArg,
440                                     bool isTailCall,
441                                     const SmallVectorImpl<ISD::OutputArg>
442                                       &Outs,
443                                     const SmallVectorImpl<ISD::InputArg> &Ins,
444                                     DebugLoc dl, SelectionDAG &DAG,
445                                     SmallVectorImpl<SDValue> &InVals) {
446  // Analyze operands of the call, assigning locations to each operand.
447  SmallVector<CCValAssign, 16> ArgLocs;
448  CCState CCInfo(CallConv, isVarArg, getTargetMachine(),
449                 ArgLocs, *DAG.getContext());
450
451  CCInfo.AnalyzeCallOperands(Outs, CC_MSP430);
452
453  // Get a count of how many bytes are to be pushed on the stack.
454  unsigned NumBytes = CCInfo.getNextStackOffset();
455
456  Chain = DAG.getCALLSEQ_START(Chain ,DAG.getConstant(NumBytes,
457                                                      getPointerTy(), true));
458
459  SmallVector<std::pair<unsigned, SDValue>, 4> RegsToPass;
460  SmallVector<SDValue, 12> MemOpChains;
461  SDValue StackPtr;
462
463  // Walk the register/memloc assignments, inserting copies/loads.
464  for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) {
465    CCValAssign &VA = ArgLocs[i];
466
467    SDValue Arg = Outs[i].Val;
468
469    // Promote the value if needed.
470    switch (VA.getLocInfo()) {
471      default: llvm_unreachable("Unknown loc info!");
472      case CCValAssign::Full: break;
473      case CCValAssign::SExt:
474        Arg = DAG.getNode(ISD::SIGN_EXTEND, dl, VA.getLocVT(), Arg);
475        break;
476      case CCValAssign::ZExt:
477        Arg = DAG.getNode(ISD::ZERO_EXTEND, dl, VA.getLocVT(), Arg);
478        break;
479      case CCValAssign::AExt:
480        Arg = DAG.getNode(ISD::ANY_EXTEND, dl, VA.getLocVT(), Arg);
481        break;
482    }
483
484    // Arguments that can be passed on register must be kept at RegsToPass
485    // vector
486    if (VA.isRegLoc()) {
487      RegsToPass.push_back(std::make_pair(VA.getLocReg(), Arg));
488    } else {
489      assert(VA.isMemLoc());
490
491      if (StackPtr.getNode() == 0)
492        StackPtr = DAG.getCopyFromReg(Chain, dl, MSP430::SPW, getPointerTy());
493
494      SDValue PtrOff = DAG.getNode(ISD::ADD, dl, getPointerTy(),
495                                   StackPtr,
496                                   DAG.getIntPtrConstant(VA.getLocMemOffset()));
497
498
499      MemOpChains.push_back(DAG.getStore(Chain, dl, Arg, PtrOff,
500                                         PseudoSourceValue::getStack(),
501                                         VA.getLocMemOffset()));
502    }
503  }
504
505  // Transform all store nodes into one single node because all store nodes are
506  // independent of each other.
507  if (!MemOpChains.empty())
508    Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other,
509                        &MemOpChains[0], MemOpChains.size());
510
511  // Build a sequence of copy-to-reg nodes chained together with token chain and
512  // flag operands which copy the outgoing args into registers.  The InFlag in
513  // necessary since all emited instructions must be stuck together.
514  SDValue InFlag;
515  for (unsigned i = 0, e = RegsToPass.size(); i != e; ++i) {
516    Chain = DAG.getCopyToReg(Chain, dl, RegsToPass[i].first,
517                             RegsToPass[i].second, InFlag);
518    InFlag = Chain.getValue(1);
519  }
520
521  // If the callee is a GlobalAddress node (quite common, every direct call is)
522  // turn it into a TargetGlobalAddress node so that legalize doesn't hack it.
523  // Likewise ExternalSymbol -> TargetExternalSymbol.
524  if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee))
525    Callee = DAG.getTargetGlobalAddress(G->getGlobal(), MVT::i16);
526  else if (ExternalSymbolSDNode *E = dyn_cast<ExternalSymbolSDNode>(Callee))
527    Callee = DAG.getTargetExternalSymbol(E->getSymbol(), MVT::i16);
528
529  // Returns a chain & a flag for retval copy to use.
530  SDVTList NodeTys = DAG.getVTList(MVT::Other, MVT::Flag);
531  SmallVector<SDValue, 8> Ops;
532  Ops.push_back(Chain);
533  Ops.push_back(Callee);
534
535  // Add argument registers to the end of the list so that they are
536  // known live into the call.
537  for (unsigned i = 0, e = RegsToPass.size(); i != e; ++i)
538    Ops.push_back(DAG.getRegister(RegsToPass[i].first,
539                                  RegsToPass[i].second.getValueType()));
540
541  if (InFlag.getNode())
542    Ops.push_back(InFlag);
543
544  Chain = DAG.getNode(MSP430ISD::CALL, dl, NodeTys, &Ops[0], Ops.size());
545  InFlag = Chain.getValue(1);
546
547  // Create the CALLSEQ_END node.
548  Chain = DAG.getCALLSEQ_END(Chain,
549                             DAG.getConstant(NumBytes, getPointerTy(), true),
550                             DAG.getConstant(0, getPointerTy(), true),
551                             InFlag);
552  InFlag = Chain.getValue(1);
553
554  // Handle result values, copying them out of physregs into vregs that we
555  // return.
556  return LowerCallResult(Chain, InFlag, CallConv, isVarArg, Ins, dl,
557                         DAG, InVals);
558}
559
560/// LowerCallResult - Lower the result values of a call into the
561/// appropriate copies out of appropriate physical registers.
562///
563SDValue
564MSP430TargetLowering::LowerCallResult(SDValue Chain, SDValue InFlag,
565                                      CallingConv::ID CallConv, bool isVarArg,
566                                      const SmallVectorImpl<ISD::InputArg> &Ins,
567                                      DebugLoc dl, SelectionDAG &DAG,
568                                      SmallVectorImpl<SDValue> &InVals) {
569
570  // Assign locations to each value returned by this call.
571  SmallVector<CCValAssign, 16> RVLocs;
572  CCState CCInfo(CallConv, isVarArg, getTargetMachine(),
573                 RVLocs, *DAG.getContext());
574
575  CCInfo.AnalyzeCallResult(Ins, RetCC_MSP430);
576
577  // Copy all of the result registers out of their specified physreg.
578  for (unsigned i = 0; i != RVLocs.size(); ++i) {
579    Chain = DAG.getCopyFromReg(Chain, dl, RVLocs[i].getLocReg(),
580                               RVLocs[i].getValVT(), InFlag).getValue(1);
581    InFlag = Chain.getValue(2);
582    InVals.push_back(Chain.getValue(0));
583  }
584
585  return Chain;
586}
587
588SDValue MSP430TargetLowering::LowerShifts(SDValue Op,
589                                          SelectionDAG &DAG) {
590  unsigned Opc = Op.getOpcode();
591  SDNode* N = Op.getNode();
592  EVT VT = Op.getValueType();
593  DebugLoc dl = N->getDebugLoc();
594
595  // We currently only lower shifts of constant argument.
596  if (!isa<ConstantSDNode>(N->getOperand(1)))
597    return SDValue();
598
599  uint64_t ShiftAmount = cast<ConstantSDNode>(N->getOperand(1))->getZExtValue();
600
601  // Expand the stuff into sequence of shifts.
602  // FIXME: for some shift amounts this might be done better!
603  // E.g.: foo >> (8 + N) => sxt(swpb(foo)) >> N
604  SDValue Victim = N->getOperand(0);
605
606  if (Opc == ISD::SRL && ShiftAmount) {
607    // Emit a special goodness here:
608    // srl A, 1 => clrc; rrc A
609    Victim = DAG.getNode(MSP430ISD::RRC, dl, VT, Victim);
610    ShiftAmount -= 1;
611  }
612
613  while (ShiftAmount--)
614    Victim = DAG.getNode((Opc == ISD::SHL ? MSP430ISD::RLA : MSP430ISD::RRA),
615                         dl, VT, Victim);
616
617  return Victim;
618}
619
620SDValue MSP430TargetLowering::LowerGlobalAddress(SDValue Op, SelectionDAG &DAG) {
621  const GlobalValue *GV = cast<GlobalAddressSDNode>(Op)->getGlobal();
622  int64_t Offset = cast<GlobalAddressSDNode>(Op)->getOffset();
623
624  // Create the TargetGlobalAddress node, folding in the constant offset.
625  SDValue Result = DAG.getTargetGlobalAddress(GV, getPointerTy(), Offset);
626  return DAG.getNode(MSP430ISD::Wrapper, Op.getDebugLoc(),
627                     getPointerTy(), Result);
628}
629
630SDValue MSP430TargetLowering::LowerExternalSymbol(SDValue Op,
631                                                  SelectionDAG &DAG) {
632  DebugLoc dl = Op.getDebugLoc();
633  const char *Sym = cast<ExternalSymbolSDNode>(Op)->getSymbol();
634  SDValue Result = DAG.getTargetExternalSymbol(Sym, getPointerTy());
635
636  return DAG.getNode(MSP430ISD::Wrapper, dl, getPointerTy(), Result);;
637}
638
639static SDValue EmitCMP(SDValue &LHS, SDValue &RHS, SDValue &TargetCC,
640                       ISD::CondCode CC,
641                       DebugLoc dl, SelectionDAG &DAG) {
642  // FIXME: Handle bittests someday
643  assert(!LHS.getValueType().isFloatingPoint() && "We don't handle FP yet");
644
645  // FIXME: Handle jump negative someday
646  MSP430CC::CondCodes TCC = MSP430CC::COND_INVALID;
647  switch (CC) {
648  default: llvm_unreachable("Invalid integer condition!");
649  case ISD::SETEQ:
650    TCC = MSP430CC::COND_E;     // aka COND_Z
651    // Minor optimization: if RHS is a constant, swap operands, then the
652    // constant can be folded into comparison.
653    if (RHS.getOpcode() == ISD::Constant)
654      std::swap(LHS, RHS);
655    break;
656  case ISD::SETNE:
657    TCC = MSP430CC::COND_NE;    // aka COND_NZ
658    // Minor optimization: if RHS is a constant, swap operands, then the
659    // constant can be folded into comparison.
660    if (RHS.getOpcode() == ISD::Constant)
661      std::swap(LHS, RHS);
662    break;
663  case ISD::SETULE:
664    std::swap(LHS, RHS);        // FALLTHROUGH
665  case ISD::SETUGE:
666    TCC = MSP430CC::COND_HS;    // aka COND_C
667    break;
668  case ISD::SETUGT:
669    std::swap(LHS, RHS);        // FALLTHROUGH
670  case ISD::SETULT:
671    TCC = MSP430CC::COND_LO;    // aka COND_NC
672    break;
673  case ISD::SETLE:
674    std::swap(LHS, RHS);        // FALLTHROUGH
675  case ISD::SETGE:
676    TCC = MSP430CC::COND_GE;
677    break;
678  case ISD::SETGT:
679    std::swap(LHS, RHS);        // FALLTHROUGH
680  case ISD::SETLT:
681    TCC = MSP430CC::COND_L;
682    break;
683  }
684
685  TargetCC = DAG.getConstant(TCC, MVT::i8);
686  return DAG.getNode(MSP430ISD::CMP, dl, MVT::Flag, LHS, RHS);
687}
688
689
690SDValue MSP430TargetLowering::LowerBR_CC(SDValue Op, SelectionDAG &DAG) {
691  SDValue Chain = Op.getOperand(0);
692  ISD::CondCode CC = cast<CondCodeSDNode>(Op.getOperand(1))->get();
693  SDValue LHS   = Op.getOperand(2);
694  SDValue RHS   = Op.getOperand(3);
695  SDValue Dest  = Op.getOperand(4);
696  DebugLoc dl   = Op.getDebugLoc();
697
698  SDValue TargetCC;
699  SDValue Flag = EmitCMP(LHS, RHS, TargetCC, CC, dl, DAG);
700
701  return DAG.getNode(MSP430ISD::BR_CC, dl, Op.getValueType(),
702                     Chain, Dest, TargetCC, Flag);
703}
704
705
706SDValue MSP430TargetLowering::LowerSETCC(SDValue Op, SelectionDAG &DAG) {
707  SDValue LHS   = Op.getOperand(0);
708  SDValue RHS   = Op.getOperand(1);
709  DebugLoc dl   = Op.getDebugLoc();
710
711  // If we are doing an AND and testing against zero, then the CMP
712  // will not be generated.  The AND (or BIT) will generate the condition codes,
713  // but they are different from CMP.
714  bool andCC = false;
715  if (ConstantSDNode *RHSC = dyn_cast<ConstantSDNode>(RHS)) {
716    if (RHSC->isNullValue() && LHS.hasOneUse() &&
717        (LHS.getOpcode() == ISD::AND ||
718         (LHS.getOpcode() == ISD::TRUNCATE &&
719          LHS.getOperand(0).getOpcode() == ISD::AND))) {
720      andCC = true;
721    }
722  }
723  ISD::CondCode CC = cast<CondCodeSDNode>(Op.getOperand(2))->get();
724  SDValue TargetCC;
725  SDValue Flag = EmitCMP(LHS, RHS, TargetCC, CC, dl, DAG);
726
727  // Get the condition codes directly from the status register, if its easy.
728  // Otherwise a branch will be generated.  Note that the AND and BIT
729  // instructions generate different flags than CMP, the carry bit can be used
730  // for NE/EQ.
731  bool Invert = false;
732  bool Shift = false;
733  bool Convert = true;
734  switch (cast<ConstantSDNode>(TargetCC)->getZExtValue()) {
735   default:
736    Convert = false;
737    break;
738   case MSP430CC::COND_HS:
739     // Res = SRW & 1, no processing is required
740     break;
741    case MSP430CC::COND_LO:
742     // Res = ~(SRW & 1)
743     Invert = true;
744     break;
745    case MSP430CC::COND_NE:
746     if (andCC) {
747       // C = ~Z, thus Res = SRW & 1, no processing is required
748     } else {
749       // Res = (SRW >> 1) & 1
750       Shift = true;
751     }
752     break;
753    case MSP430CC::COND_E:
754     if (andCC) {
755       // C = ~Z, thus Res = ~(SRW & 1)
756     } else {
757       // Res = ~((SRW >> 1) & 1)
758       Shift = true;
759     }
760     Invert = true;
761     break;
762  }
763  EVT VT = Op.getValueType();
764  SDValue One  = DAG.getConstant(1, VT);
765  if (Convert) {
766    SDValue SR = DAG.getCopyFromReg(DAG.getEntryNode(), dl, MSP430::SRW,
767                                     MVT::i16, Flag);
768    if (Shift)
769      // FIXME: somewhere this is turned into a SRL, lower it MSP specific?
770      SR = DAG.getNode(ISD::SRA, dl, MVT::i16, SR, One);
771    SR = DAG.getNode(ISD::AND, dl, MVT::i16, SR, One);
772    if (Invert)
773      SR = DAG.getNode(ISD::XOR, dl, MVT::i16, SR, One);
774    return SR;
775  } else {
776    SDValue Zero = DAG.getConstant(0, VT);
777    SDVTList VTs = DAG.getVTList(Op.getValueType(), MVT::Flag);
778    SmallVector<SDValue, 4> Ops;
779    Ops.push_back(One);
780    Ops.push_back(Zero);
781    Ops.push_back(TargetCC);
782    Ops.push_back(Flag);
783    return DAG.getNode(MSP430ISD::SELECT_CC, dl, VTs, &Ops[0], Ops.size());
784  }
785}
786
787SDValue MSP430TargetLowering::LowerSELECT_CC(SDValue Op, SelectionDAG &DAG) {
788  SDValue LHS    = Op.getOperand(0);
789  SDValue RHS    = Op.getOperand(1);
790  SDValue TrueV  = Op.getOperand(2);
791  SDValue FalseV = Op.getOperand(3);
792  ISD::CondCode CC = cast<CondCodeSDNode>(Op.getOperand(4))->get();
793  DebugLoc dl    = Op.getDebugLoc();
794
795  SDValue TargetCC;
796  SDValue Flag = EmitCMP(LHS, RHS, TargetCC, CC, dl, DAG);
797
798  SDVTList VTs = DAG.getVTList(Op.getValueType(), MVT::Flag);
799  SmallVector<SDValue, 4> Ops;
800  Ops.push_back(TrueV);
801  Ops.push_back(FalseV);
802  Ops.push_back(TargetCC);
803  Ops.push_back(Flag);
804
805  return DAG.getNode(MSP430ISD::SELECT_CC, dl, VTs, &Ops[0], Ops.size());
806}
807
808SDValue MSP430TargetLowering::LowerSIGN_EXTEND(SDValue Op,
809                                               SelectionDAG &DAG) {
810  SDValue Val = Op.getOperand(0);
811  EVT VT      = Op.getValueType();
812  DebugLoc dl = Op.getDebugLoc();
813
814  assert(VT == MVT::i16 && "Only support i16 for now!");
815
816  return DAG.getNode(ISD::SIGN_EXTEND_INREG, dl, VT,
817                     DAG.getNode(ISD::ANY_EXTEND, dl, VT, Val),
818                     DAG.getValueType(Val.getValueType()));
819}
820
821SDValue MSP430TargetLowering::getReturnAddressFrameIndex(SelectionDAG &DAG) {
822  MachineFunction &MF = DAG.getMachineFunction();
823  MSP430MachineFunctionInfo *FuncInfo = MF.getInfo<MSP430MachineFunctionInfo>();
824  int ReturnAddrIndex = FuncInfo->getRAIndex();
825
826  if (ReturnAddrIndex == 0) {
827    // Set up a frame object for the return address.
828    uint64_t SlotSize = TD->getPointerSize();
829    ReturnAddrIndex = MF.getFrameInfo()->CreateFixedObject(SlotSize, -SlotSize,
830                                                           true, false);
831    FuncInfo->setRAIndex(ReturnAddrIndex);
832  }
833
834  return DAG.getFrameIndex(ReturnAddrIndex, getPointerTy());
835}
836
837SDValue MSP430TargetLowering::LowerRETURNADDR(SDValue Op, SelectionDAG &DAG) {
838  unsigned Depth = cast<ConstantSDNode>(Op.getOperand(0))->getZExtValue();
839  DebugLoc dl = Op.getDebugLoc();
840
841  if (Depth > 0) {
842    SDValue FrameAddr = LowerFRAMEADDR(Op, DAG);
843    SDValue Offset =
844      DAG.getConstant(TD->getPointerSize(), MVT::i16);
845    return DAG.getLoad(getPointerTy(), dl, DAG.getEntryNode(),
846                       DAG.getNode(ISD::ADD, dl, getPointerTy(),
847                                   FrameAddr, Offset),
848                       NULL, 0);
849  }
850
851  // Just load the return address.
852  SDValue RetAddrFI = getReturnAddressFrameIndex(DAG);
853  return DAG.getLoad(getPointerTy(), dl, DAG.getEntryNode(),
854                     RetAddrFI, NULL, 0);
855}
856
857SDValue MSP430TargetLowering::LowerFRAMEADDR(SDValue Op, SelectionDAG &DAG) {
858  MachineFrameInfo *MFI = DAG.getMachineFunction().getFrameInfo();
859  MFI->setFrameAddressIsTaken(true);
860  EVT VT = Op.getValueType();
861  DebugLoc dl = Op.getDebugLoc();  // FIXME probably not meaningful
862  unsigned Depth = cast<ConstantSDNode>(Op.getOperand(0))->getZExtValue();
863  SDValue FrameAddr = DAG.getCopyFromReg(DAG.getEntryNode(), dl,
864                                         MSP430::FPW, VT);
865  while (Depth--)
866    FrameAddr = DAG.getLoad(VT, dl, DAG.getEntryNode(), FrameAddr, NULL, 0);
867  return FrameAddr;
868}
869
870/// getPostIndexedAddressParts - returns true by value, base pointer and
871/// offset pointer and addressing mode by reference if this node can be
872/// combined with a load / store to form a post-indexed load / store.
873bool MSP430TargetLowering::getPostIndexedAddressParts(SDNode *N, SDNode *Op,
874                                                      SDValue &Base,
875                                                      SDValue &Offset,
876                                                      ISD::MemIndexedMode &AM,
877                                                      SelectionDAG &DAG) const {
878
879  LoadSDNode *LD = cast<LoadSDNode>(N);
880  if (LD->getExtensionType() != ISD::NON_EXTLOAD)
881    return false;
882
883  EVT VT = LD->getMemoryVT();
884  if (VT != MVT::i8 && VT != MVT::i16)
885    return false;
886
887  if (Op->getOpcode() != ISD::ADD)
888    return false;
889
890  if (ConstantSDNode *RHS = dyn_cast<ConstantSDNode>(Op->getOperand(1))) {
891    uint64_t RHSC = RHS->getZExtValue();
892    if ((VT == MVT::i16 && RHSC != 2) ||
893        (VT == MVT::i8 && RHSC != 1))
894      return false;
895
896    Base = Op->getOperand(0);
897    Offset = DAG.getConstant(RHSC, VT);
898    AM = ISD::POST_INC;
899    return true;
900  }
901
902  return false;
903}
904
905
906const char *MSP430TargetLowering::getTargetNodeName(unsigned Opcode) const {
907  switch (Opcode) {
908  default: return NULL;
909  case MSP430ISD::RET_FLAG:           return "MSP430ISD::RET_FLAG";
910  case MSP430ISD::RETI_FLAG:          return "MSP430ISD::RETI_FLAG";
911  case MSP430ISD::RRA:                return "MSP430ISD::RRA";
912  case MSP430ISD::RLA:                return "MSP430ISD::RLA";
913  case MSP430ISD::RRC:                return "MSP430ISD::RRC";
914  case MSP430ISD::CALL:               return "MSP430ISD::CALL";
915  case MSP430ISD::Wrapper:            return "MSP430ISD::Wrapper";
916  case MSP430ISD::BR_CC:              return "MSP430ISD::BR_CC";
917  case MSP430ISD::CMP:                return "MSP430ISD::CMP";
918  case MSP430ISD::SELECT_CC:          return "MSP430ISD::SELECT_CC";
919  }
920}
921
922//===----------------------------------------------------------------------===//
923//  Other Lowering Code
924//===----------------------------------------------------------------------===//
925
926MachineBasicBlock*
927MSP430TargetLowering::EmitInstrWithCustomInserter(MachineInstr *MI,
928                                                  MachineBasicBlock *BB,
929                   DenseMap<MachineBasicBlock*, MachineBasicBlock*> *EM) const {
930  const TargetInstrInfo &TII = *getTargetMachine().getInstrInfo();
931  DebugLoc dl = MI->getDebugLoc();
932  assert((MI->getOpcode() == MSP430::Select16 ||
933          MI->getOpcode() == MSP430::Select8) &&
934         "Unexpected instr type to insert");
935
936  // To "insert" a SELECT instruction, we actually have to insert the diamond
937  // control-flow pattern.  The incoming instruction knows the destination vreg
938  // to set, the condition code register to branch on, the true/false values to
939  // select between, and a branch opcode to use.
940  const BasicBlock *LLVM_BB = BB->getBasicBlock();
941  MachineFunction::iterator I = BB;
942  ++I;
943
944  //  thisMBB:
945  //  ...
946  //   TrueVal = ...
947  //   cmpTY ccX, r1, r2
948  //   jCC copy1MBB
949  //   fallthrough --> copy0MBB
950  MachineBasicBlock *thisMBB = BB;
951  MachineFunction *F = BB->getParent();
952  MachineBasicBlock *copy0MBB = F->CreateMachineBasicBlock(LLVM_BB);
953  MachineBasicBlock *copy1MBB = F->CreateMachineBasicBlock(LLVM_BB);
954  BuildMI(BB, dl, TII.get(MSP430::JCC))
955    .addMBB(copy1MBB)
956    .addImm(MI->getOperand(3).getImm());
957  F->insert(I, copy0MBB);
958  F->insert(I, copy1MBB);
959  // Inform sdisel of the edge changes.
960  for (MachineBasicBlock::succ_iterator SI = BB->succ_begin(),
961         SE = BB->succ_end(); SI != SE; ++SI)
962    EM->insert(std::make_pair(*SI, copy1MBB));
963  // Update machine-CFG edges by transferring all successors of the current
964  // block to the new block which will contain the Phi node for the select.
965  copy1MBB->transferSuccessors(BB);
966  // Next, add the true and fallthrough blocks as its successors.
967  BB->addSuccessor(copy0MBB);
968  BB->addSuccessor(copy1MBB);
969
970  //  copy0MBB:
971  //   %FalseValue = ...
972  //   # fallthrough to copy1MBB
973  BB = copy0MBB;
974
975  // Update machine-CFG edges
976  BB->addSuccessor(copy1MBB);
977
978  //  copy1MBB:
979  //   %Result = phi [ %FalseValue, copy0MBB ], [ %TrueValue, thisMBB ]
980  //  ...
981  BB = copy1MBB;
982  BuildMI(BB, dl, TII.get(MSP430::PHI),
983          MI->getOperand(0).getReg())
984    .addReg(MI->getOperand(2).getReg()).addMBB(copy0MBB)
985    .addReg(MI->getOperand(1).getReg()).addMBB(thisMBB);
986
987  F->DeleteMachineInstr(MI);   // The pseudo instruction is gone now.
988  return BB;
989}
990