TargetLowering.h revision d850ac79b57e6e0bf68ee93a94d0b3dcd9f6ca35
1//===-- llvm/Target/TargetLowering.h - Target Lowering Info -----*- C++ -*-===// 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 describes how to lower LLVM code to machine code. This has two 11// main components: 12// 13// 1. Which ValueTypes are natively supported by the target. 14// 2. Which operations are supported for supported ValueTypes. 15// 3. Cost thresholds for alternative implementations of certain operations. 16// 17// In addition it has a few other components, like information about FP 18// immediates. 19// 20//===----------------------------------------------------------------------===// 21 22#ifndef LLVM_TARGET_TARGETLOWERING_H 23#define LLVM_TARGET_TARGETLOWERING_H 24 25#include "llvm/CallingConv.h" 26#include "llvm/InlineAsm.h" 27#include "llvm/CodeGen/SelectionDAGNodes.h" 28#include "llvm/CodeGen/RuntimeLibcalls.h" 29#include "llvm/ADT/APFloat.h" 30#include "llvm/ADT/DenseMap.h" 31#include "llvm/ADT/SmallSet.h" 32#include "llvm/ADT/SmallVector.h" 33#include "llvm/ADT/STLExtras.h" 34#include "llvm/Support/DebugLoc.h" 35#include "llvm/Target/TargetMachine.h" 36#include <climits> 37#include <map> 38#include <vector> 39 40namespace llvm { 41 class AllocaInst; 42 class CallInst; 43 class Function; 44 class FastISel; 45 class MachineBasicBlock; 46 class MachineFunction; 47 class MachineFrameInfo; 48 class MachineInstr; 49 class MachineJumpTableInfo; 50 class MachineModuleInfo; 51 class MCContext; 52 class MCExpr; 53 class SDNode; 54 class SDValue; 55 class SelectionDAG; 56 class TargetData; 57 class TargetMachine; 58 class TargetRegisterClass; 59 class TargetSubtarget; 60 class TargetLoweringObjectFile; 61 class Value; 62 63 // FIXME: should this be here? 64 namespace TLSModel { 65 enum Model { 66 GeneralDynamic, 67 LocalDynamic, 68 InitialExec, 69 LocalExec 70 }; 71 } 72 TLSModel::Model getTLSModel(const GlobalValue *GV, Reloc::Model reloc); 73 74 75//===----------------------------------------------------------------------===// 76/// TargetLowering - This class defines information used to lower LLVM code to 77/// legal SelectionDAG operators that the target instruction selector can accept 78/// natively. 79/// 80/// This class also defines callbacks that targets must implement to lower 81/// target-specific constructs to SelectionDAG operators. 82/// 83class TargetLowering { 84 TargetLowering(const TargetLowering&); // DO NOT IMPLEMENT 85 void operator=(const TargetLowering&); // DO NOT IMPLEMENT 86public: 87 /// LegalizeAction - This enum indicates whether operations are valid for a 88 /// target, and if not, what action should be used to make them valid. 89 enum LegalizeAction { 90 Legal, // The target natively supports this operation. 91 Promote, // This operation should be executed in a larger type. 92 Expand, // Try to expand this to other ops, otherwise use a libcall. 93 Custom // Use the LowerOperation hook to implement custom lowering. 94 }; 95 96 enum BooleanContent { // How the target represents true/false values. 97 UndefinedBooleanContent, // Only bit 0 counts, the rest can hold garbage. 98 ZeroOrOneBooleanContent, // All bits zero except for bit 0. 99 ZeroOrNegativeOneBooleanContent // All bits equal to bit 0. 100 }; 101 102 enum SchedPreference { 103 SchedulingForLatency, // Scheduling for shortest total latency. 104 SchedulingForRegPressure // Scheduling for lowest register pressure. 105 }; 106 107 /// NOTE: The constructor takes ownership of TLOF. 108 explicit TargetLowering(TargetMachine &TM, TargetLoweringObjectFile *TLOF); 109 virtual ~TargetLowering(); 110 111 TargetMachine &getTargetMachine() const { return TM; } 112 const TargetData *getTargetData() const { return TD; } 113 TargetLoweringObjectFile &getObjFileLowering() const { return TLOF; } 114 115 bool isBigEndian() const { return !IsLittleEndian; } 116 bool isLittleEndian() const { return IsLittleEndian; } 117 MVT getPointerTy() const { return PointerTy; } 118 MVT getShiftAmountTy() const { return ShiftAmountTy; } 119 120 /// isSelectExpensive - Return true if the select operation is expensive for 121 /// this target. 122 bool isSelectExpensive() const { return SelectIsExpensive; } 123 124 /// isIntDivCheap() - Return true if integer divide is usually cheaper than 125 /// a sequence of several shifts, adds, and multiplies for this target. 126 bool isIntDivCheap() const { return IntDivIsCheap; } 127 128 /// isPow2DivCheap() - Return true if pow2 div is cheaper than a chain of 129 /// srl/add/sra. 130 bool isPow2DivCheap() const { return Pow2DivIsCheap; } 131 132 /// getSetCCResultType - Return the ValueType of the result of SETCC 133 /// operations. Also used to obtain the target's preferred type for 134 /// the condition operand of SELECT and BRCOND nodes. In the case of 135 /// BRCOND the argument passed is MVT::Other since there are no other 136 /// operands to get a type hint from. 137 virtual 138 MVT::SimpleValueType getSetCCResultType(EVT VT) const; 139 140 /// getCmpLibcallReturnType - Return the ValueType for comparison 141 /// libcalls. Comparions libcalls include floating point comparion calls, 142 /// and Ordered/Unordered check calls on floating point numbers. 143 virtual 144 MVT::SimpleValueType getCmpLibcallReturnType() const; 145 146 /// getBooleanContents - For targets without i1 registers, this gives the 147 /// nature of the high-bits of boolean values held in types wider than i1. 148 /// "Boolean values" are special true/false values produced by nodes like 149 /// SETCC and consumed (as the condition) by nodes like SELECT and BRCOND. 150 /// Not to be confused with general values promoted from i1. 151 BooleanContent getBooleanContents() const { return BooleanContents;} 152 153 /// getSchedulingPreference - Return target scheduling preference. 154 SchedPreference getSchedulingPreference() const { 155 return SchedPreferenceInfo; 156 } 157 158 /// getRegClassFor - Return the register class that should be used for the 159 /// specified value type. This may only be called on legal types. 160 TargetRegisterClass *getRegClassFor(EVT VT) const { 161 assert(VT.isSimple() && "getRegClassFor called on illegal type!"); 162 TargetRegisterClass *RC = RegClassForVT[VT.getSimpleVT().SimpleTy]; 163 assert(RC && "This value type is not natively supported!"); 164 return RC; 165 } 166 167 /// isTypeLegal - Return true if the target has native support for the 168 /// specified value type. This means that it has a register that directly 169 /// holds it without promotions or expansions. 170 bool isTypeLegal(EVT VT) const { 171 assert(!VT.isSimple() || 172 (unsigned)VT.getSimpleVT().SimpleTy < array_lengthof(RegClassForVT)); 173 return VT.isSimple() && RegClassForVT[VT.getSimpleVT().SimpleTy] != 0; 174 } 175 176 class ValueTypeActionImpl { 177 /// ValueTypeActions - This is a bitvector that contains two bits for each 178 /// value type, where the two bits correspond to the LegalizeAction enum. 179 /// This can be queried with "getTypeAction(VT)". 180 /// dimension by (MVT::MAX_ALLOWED_VALUETYPE/32) * 2 181 uint32_t ValueTypeActions[(MVT::MAX_ALLOWED_VALUETYPE/32)*2]; 182 public: 183 ValueTypeActionImpl() { 184 ValueTypeActions[0] = ValueTypeActions[1] = 0; 185 ValueTypeActions[2] = ValueTypeActions[3] = 0; 186 } 187 ValueTypeActionImpl(const ValueTypeActionImpl &RHS) { 188 ValueTypeActions[0] = RHS.ValueTypeActions[0]; 189 ValueTypeActions[1] = RHS.ValueTypeActions[1]; 190 ValueTypeActions[2] = RHS.ValueTypeActions[2]; 191 ValueTypeActions[3] = RHS.ValueTypeActions[3]; 192 } 193 194 LegalizeAction getTypeAction(LLVMContext &Context, EVT VT) const { 195 if (VT.isExtended()) { 196 if (VT.isVector()) { 197 return VT.isPow2VectorType() ? Expand : Promote; 198 } 199 if (VT.isInteger()) 200 // First promote to a power-of-two size, then expand if necessary. 201 return VT == VT.getRoundIntegerType(Context) ? Expand : Promote; 202 assert(0 && "Unsupported extended type!"); 203 return Legal; 204 } 205 unsigned I = VT.getSimpleVT().SimpleTy; 206 assert(I<4*array_lengthof(ValueTypeActions)*sizeof(ValueTypeActions[0])); 207 return (LegalizeAction)((ValueTypeActions[I>>4] >> ((2*I) & 31)) & 3); 208 } 209 void setTypeAction(EVT VT, LegalizeAction Action) { 210 unsigned I = VT.getSimpleVT().SimpleTy; 211 assert(I<4*array_lengthof(ValueTypeActions)*sizeof(ValueTypeActions[0])); 212 ValueTypeActions[I>>4] |= Action << ((I*2) & 31); 213 } 214 }; 215 216 const ValueTypeActionImpl &getValueTypeActions() const { 217 return ValueTypeActions; 218 } 219 220 /// getTypeAction - Return how we should legalize values of this type, either 221 /// it is already legal (return 'Legal') or we need to promote it to a larger 222 /// type (return 'Promote'), or we need to expand it into multiple registers 223 /// of smaller integer type (return 'Expand'). 'Custom' is not an option. 224 LegalizeAction getTypeAction(LLVMContext &Context, EVT VT) const { 225 return ValueTypeActions.getTypeAction(Context, VT); 226 } 227 228 /// getTypeToTransformTo - For types supported by the target, this is an 229 /// identity function. For types that must be promoted to larger types, this 230 /// returns the larger type to promote to. For integer types that are larger 231 /// than the largest integer register, this contains one step in the expansion 232 /// to get to the smaller register. For illegal floating point types, this 233 /// returns the integer type to transform to. 234 EVT getTypeToTransformTo(LLVMContext &Context, EVT VT) const { 235 if (VT.isSimple()) { 236 assert((unsigned)VT.getSimpleVT().SimpleTy < 237 array_lengthof(TransformToType)); 238 EVT NVT = TransformToType[VT.getSimpleVT().SimpleTy]; 239 assert(getTypeAction(Context, NVT) != Promote && 240 "Promote may not follow Expand or Promote"); 241 return NVT; 242 } 243 244 if (VT.isVector()) { 245 EVT NVT = VT.getPow2VectorType(Context); 246 if (NVT == VT) { 247 // Vector length is a power of 2 - split to half the size. 248 unsigned NumElts = VT.getVectorNumElements(); 249 EVT EltVT = VT.getVectorElementType(); 250 return (NumElts == 1) ? 251 EltVT : EVT::getVectorVT(Context, EltVT, NumElts / 2); 252 } 253 // Promote to a power of two size, avoiding multi-step promotion. 254 return getTypeAction(Context, NVT) == Promote ? 255 getTypeToTransformTo(Context, NVT) : NVT; 256 } else if (VT.isInteger()) { 257 EVT NVT = VT.getRoundIntegerType(Context); 258 if (NVT == VT) 259 // Size is a power of two - expand to half the size. 260 return EVT::getIntegerVT(Context, VT.getSizeInBits() / 2); 261 else 262 // Promote to a power of two size, avoiding multi-step promotion. 263 return getTypeAction(Context, NVT) == Promote ? 264 getTypeToTransformTo(Context, NVT) : NVT; 265 } 266 assert(0 && "Unsupported extended type!"); 267 return MVT(MVT::Other); // Not reached 268 } 269 270 /// getTypeToExpandTo - For types supported by the target, this is an 271 /// identity function. For types that must be expanded (i.e. integer types 272 /// that are larger than the largest integer register or illegal floating 273 /// point types), this returns the largest legal type it will be expanded to. 274 EVT getTypeToExpandTo(LLVMContext &Context, EVT VT) const { 275 assert(!VT.isVector()); 276 while (true) { 277 switch (getTypeAction(Context, VT)) { 278 case Legal: 279 return VT; 280 case Expand: 281 VT = getTypeToTransformTo(Context, VT); 282 break; 283 default: 284 assert(false && "Type is not legal nor is it to be expanded!"); 285 return VT; 286 } 287 } 288 return VT; 289 } 290 291 /// getVectorTypeBreakdown - Vector types are broken down into some number of 292 /// legal first class types. For example, EVT::v8f32 maps to 2 EVT::v4f32 293 /// with Altivec or SSE1, or 8 promoted EVT::f64 values with the X86 FP stack. 294 /// Similarly, EVT::v2i64 turns into 4 EVT::i32 values with both PPC and X86. 295 /// 296 /// This method returns the number of registers needed, and the VT for each 297 /// register. It also returns the VT and quantity of the intermediate values 298 /// before they are promoted/expanded. 299 /// 300 unsigned getVectorTypeBreakdown(LLVMContext &Context, EVT VT, 301 EVT &IntermediateVT, 302 unsigned &NumIntermediates, 303 EVT &RegisterVT) const; 304 305 /// getTgtMemIntrinsic: Given an intrinsic, checks if on the target the 306 /// intrinsic will need to map to a MemIntrinsicNode (touches memory). If 307 /// this is the case, it returns true and store the intrinsic 308 /// information into the IntrinsicInfo that was passed to the function. 309 struct IntrinsicInfo { 310 unsigned opc; // target opcode 311 EVT memVT; // memory VT 312 const Value* ptrVal; // value representing memory location 313 int offset; // offset off of ptrVal 314 unsigned align; // alignment 315 bool vol; // is volatile? 316 bool readMem; // reads memory? 317 bool writeMem; // writes memory? 318 }; 319 320 virtual bool getTgtMemIntrinsic(IntrinsicInfo &Info, 321 CallInst &I, unsigned Intrinsic) { 322 return false; 323 } 324 325 /// isFPImmLegal - Returns true if the target can instruction select the 326 /// specified FP immediate natively. If false, the legalizer will materialize 327 /// the FP immediate as a load from a constant pool. 328 virtual bool isFPImmLegal(const APFloat &Imm, EVT VT) const { 329 return false; 330 } 331 332 /// isShuffleMaskLegal - Targets can use this to indicate that they only 333 /// support *some* VECTOR_SHUFFLE operations, those with specific masks. 334 /// By default, if a target supports the VECTOR_SHUFFLE node, all mask values 335 /// are assumed to be legal. 336 virtual bool isShuffleMaskLegal(const SmallVectorImpl<int> &Mask, 337 EVT VT) const { 338 return true; 339 } 340 341 /// canOpTrap - Returns true if the operation can trap for the value type. 342 /// VT must be a legal type. By default, we optimistically assume most 343 /// operations don't trap except for divide and remainder. 344 virtual bool canOpTrap(unsigned Op, EVT VT) const; 345 346 /// isVectorClearMaskLegal - Similar to isShuffleMaskLegal. This is 347 /// used by Targets can use this to indicate if there is a suitable 348 /// VECTOR_SHUFFLE that can be used to replace a VAND with a constant 349 /// pool entry. 350 virtual bool isVectorClearMaskLegal(const SmallVectorImpl<int> &Mask, 351 EVT VT) const { 352 return false; 353 } 354 355 /// getOperationAction - Return how this operation should be treated: either 356 /// it is legal, needs to be promoted to a larger size, needs to be 357 /// expanded to some other code sequence, or the target has a custom expander 358 /// for it. 359 LegalizeAction getOperationAction(unsigned Op, EVT VT) const { 360 if (VT.isExtended()) return Expand; 361 assert(Op < array_lengthof(OpActions[0]) && 362 (unsigned)VT.getSimpleVT().SimpleTy < sizeof(OpActions[0][0])*8 && 363 "Table isn't big enough!"); 364 unsigned I = (unsigned) VT.getSimpleVT().SimpleTy; 365 unsigned J = I & 31; 366 I = I >> 5; 367 return (LegalizeAction)((OpActions[I][Op] >> (J*2) ) & 3); 368 } 369 370 /// isOperationLegalOrCustom - Return true if the specified operation is 371 /// legal on this target or can be made legal with custom lowering. This 372 /// is used to help guide high-level lowering decisions. 373 bool isOperationLegalOrCustom(unsigned Op, EVT VT) const { 374 return (VT == MVT::Other || isTypeLegal(VT)) && 375 (getOperationAction(Op, VT) == Legal || 376 getOperationAction(Op, VT) == Custom); 377 } 378 379 /// isOperationLegal - Return true if the specified operation is legal on this 380 /// target. 381 bool isOperationLegal(unsigned Op, EVT VT) const { 382 return (VT == MVT::Other || isTypeLegal(VT)) && 383 getOperationAction(Op, VT) == Legal; 384 } 385 386 /// getLoadExtAction - Return how this load with extension should be treated: 387 /// either it is legal, needs to be promoted to a larger size, needs to be 388 /// expanded to some other code sequence, or the target has a custom expander 389 /// for it. 390 LegalizeAction getLoadExtAction(unsigned LType, EVT VT) const { 391 assert(LType < array_lengthof(LoadExtActions) && 392 (unsigned)VT.getSimpleVT().SimpleTy < sizeof(LoadExtActions[0])*4 && 393 "Table isn't big enough!"); 394 return (LegalizeAction)((LoadExtActions[LType] >> 395 (2*VT.getSimpleVT().SimpleTy)) & 3); 396 } 397 398 /// isLoadExtLegal - Return true if the specified load with extension is legal 399 /// on this target. 400 bool isLoadExtLegal(unsigned LType, EVT VT) const { 401 return VT.isSimple() && 402 (getLoadExtAction(LType, VT) == Legal || 403 getLoadExtAction(LType, VT) == Custom); 404 } 405 406 /// getTruncStoreAction - Return how this store with truncation should be 407 /// treated: either it is legal, needs to be promoted to a larger size, needs 408 /// to be expanded to some other code sequence, or the target has a custom 409 /// expander for it. 410 LegalizeAction getTruncStoreAction(EVT ValVT, 411 EVT MemVT) const { 412 assert((unsigned)ValVT.getSimpleVT().SimpleTy < 413 array_lengthof(TruncStoreActions) && 414 (unsigned)MemVT.getSimpleVT().SimpleTy < 415 sizeof(TruncStoreActions[0])*4 && 416 "Table isn't big enough!"); 417 return (LegalizeAction)((TruncStoreActions[ValVT.getSimpleVT().SimpleTy] >> 418 (2*MemVT.getSimpleVT().SimpleTy)) & 3); 419 } 420 421 /// isTruncStoreLegal - Return true if the specified store with truncation is 422 /// legal on this target. 423 bool isTruncStoreLegal(EVT ValVT, EVT MemVT) const { 424 return isTypeLegal(ValVT) && MemVT.isSimple() && 425 (getTruncStoreAction(ValVT, MemVT) == Legal || 426 getTruncStoreAction(ValVT, MemVT) == Custom); 427 } 428 429 /// getIndexedLoadAction - Return how the indexed load should be treated: 430 /// either it is legal, needs to be promoted to a larger size, needs to be 431 /// expanded to some other code sequence, or the target has a custom expander 432 /// for it. 433 LegalizeAction 434 getIndexedLoadAction(unsigned IdxMode, EVT VT) const { 435 assert( IdxMode < array_lengthof(IndexedModeActions[0][0]) && 436 ((unsigned)VT.getSimpleVT().SimpleTy) < MVT::LAST_VALUETYPE && 437 "Table isn't big enough!"); 438 return (LegalizeAction)((IndexedModeActions[ 439 (unsigned)VT.getSimpleVT().SimpleTy][0][IdxMode])); 440 } 441 442 /// isIndexedLoadLegal - Return true if the specified indexed load is legal 443 /// on this target. 444 bool isIndexedLoadLegal(unsigned IdxMode, EVT VT) const { 445 return VT.isSimple() && 446 (getIndexedLoadAction(IdxMode, VT) == Legal || 447 getIndexedLoadAction(IdxMode, VT) == Custom); 448 } 449 450 /// getIndexedStoreAction - Return how the indexed store should be treated: 451 /// either it is legal, needs to be promoted to a larger size, needs to be 452 /// expanded to some other code sequence, or the target has a custom expander 453 /// for it. 454 LegalizeAction 455 getIndexedStoreAction(unsigned IdxMode, EVT VT) const { 456 assert(IdxMode < array_lengthof(IndexedModeActions[0][1]) && 457 (unsigned)VT.getSimpleVT().SimpleTy < MVT::LAST_VALUETYPE && 458 "Table isn't big enough!"); 459 return (LegalizeAction)((IndexedModeActions[ 460 (unsigned)VT.getSimpleVT().SimpleTy][1][IdxMode])); 461 } 462 463 /// isIndexedStoreLegal - Return true if the specified indexed load is legal 464 /// on this target. 465 bool isIndexedStoreLegal(unsigned IdxMode, EVT VT) const { 466 return VT.isSimple() && 467 (getIndexedStoreAction(IdxMode, VT) == Legal || 468 getIndexedStoreAction(IdxMode, VT) == Custom); 469 } 470 471 /// getCondCodeAction - Return how the condition code should be treated: 472 /// either it is legal, needs to be expanded to some other code sequence, 473 /// or the target has a custom expander for it. 474 LegalizeAction 475 getCondCodeAction(ISD::CondCode CC, EVT VT) const { 476 assert((unsigned)CC < array_lengthof(CondCodeActions) && 477 (unsigned)VT.getSimpleVT().SimpleTy < sizeof(CondCodeActions[0])*4 && 478 "Table isn't big enough!"); 479 LegalizeAction Action = (LegalizeAction) 480 ((CondCodeActions[CC] >> (2*VT.getSimpleVT().SimpleTy)) & 3); 481 assert(Action != Promote && "Can't promote condition code!"); 482 return Action; 483 } 484 485 /// isCondCodeLegal - Return true if the specified condition code is legal 486 /// on this target. 487 bool isCondCodeLegal(ISD::CondCode CC, EVT VT) const { 488 return getCondCodeAction(CC, VT) == Legal || 489 getCondCodeAction(CC, VT) == Custom; 490 } 491 492 493 /// getTypeToPromoteTo - If the action for this operation is to promote, this 494 /// method returns the ValueType to promote to. 495 EVT getTypeToPromoteTo(unsigned Op, EVT VT) const { 496 assert(getOperationAction(Op, VT) == Promote && 497 "This operation isn't promoted!"); 498 499 // See if this has an explicit type specified. 500 std::map<std::pair<unsigned, MVT::SimpleValueType>, 501 MVT::SimpleValueType>::const_iterator PTTI = 502 PromoteToType.find(std::make_pair(Op, VT.getSimpleVT().SimpleTy)); 503 if (PTTI != PromoteToType.end()) return PTTI->second; 504 505 assert((VT.isInteger() || VT.isFloatingPoint()) && 506 "Cannot autopromote this type, add it with AddPromotedToType."); 507 508 EVT NVT = VT; 509 do { 510 NVT = (MVT::SimpleValueType)(NVT.getSimpleVT().SimpleTy+1); 511 assert(NVT.isInteger() == VT.isInteger() && NVT != MVT::isVoid && 512 "Didn't find type to promote to!"); 513 } while (!isTypeLegal(NVT) || 514 getOperationAction(Op, NVT) == Promote); 515 return NVT; 516 } 517 518 /// getValueType - Return the EVT corresponding to this LLVM type. 519 /// This is fixed by the LLVM operations except for the pointer size. If 520 /// AllowUnknown is true, this will return MVT::Other for types with no EVT 521 /// counterpart (e.g. structs), otherwise it will assert. 522 EVT getValueType(const Type *Ty, bool AllowUnknown = false) const { 523 EVT VT = EVT::getEVT(Ty, AllowUnknown); 524 return VT == MVT::iPTR ? PointerTy : VT; 525 } 526 527 /// getByValTypeAlignment - Return the desired alignment for ByVal aggregate 528 /// function arguments in the caller parameter area. This is the actual 529 /// alignment, not its logarithm. 530 virtual unsigned getByValTypeAlignment(const Type *Ty) const; 531 532 /// getRegisterType - Return the type of registers that this ValueType will 533 /// eventually require. 534 EVT getRegisterType(MVT VT) const { 535 assert((unsigned)VT.SimpleTy < array_lengthof(RegisterTypeForVT)); 536 return RegisterTypeForVT[VT.SimpleTy]; 537 } 538 539 /// getRegisterType - Return the type of registers that this ValueType will 540 /// eventually require. 541 EVT getRegisterType(LLVMContext &Context, EVT VT) const { 542 if (VT.isSimple()) { 543 assert((unsigned)VT.getSimpleVT().SimpleTy < 544 array_lengthof(RegisterTypeForVT)); 545 return RegisterTypeForVT[VT.getSimpleVT().SimpleTy]; 546 } 547 if (VT.isVector()) { 548 EVT VT1, RegisterVT; 549 unsigned NumIntermediates; 550 (void)getVectorTypeBreakdown(Context, VT, VT1, 551 NumIntermediates, RegisterVT); 552 return RegisterVT; 553 } 554 if (VT.isInteger()) { 555 return getRegisterType(Context, getTypeToTransformTo(Context, VT)); 556 } 557 assert(0 && "Unsupported extended type!"); 558 return EVT(MVT::Other); // Not reached 559 } 560 561 /// getNumRegisters - Return the number of registers that this ValueType will 562 /// eventually require. This is one for any types promoted to live in larger 563 /// registers, but may be more than one for types (like i64) that are split 564 /// into pieces. For types like i140, which are first promoted then expanded, 565 /// it is the number of registers needed to hold all the bits of the original 566 /// type. For an i140 on a 32 bit machine this means 5 registers. 567 unsigned getNumRegisters(LLVMContext &Context, EVT VT) const { 568 if (VT.isSimple()) { 569 assert((unsigned)VT.getSimpleVT().SimpleTy < 570 array_lengthof(NumRegistersForVT)); 571 return NumRegistersForVT[VT.getSimpleVT().SimpleTy]; 572 } 573 if (VT.isVector()) { 574 EVT VT1, VT2; 575 unsigned NumIntermediates; 576 return getVectorTypeBreakdown(Context, VT, VT1, NumIntermediates, VT2); 577 } 578 if (VT.isInteger()) { 579 unsigned BitWidth = VT.getSizeInBits(); 580 unsigned RegWidth = getRegisterType(Context, VT).getSizeInBits(); 581 return (BitWidth + RegWidth - 1) / RegWidth; 582 } 583 assert(0 && "Unsupported extended type!"); 584 return 0; // Not reached 585 } 586 587 /// ShouldShrinkFPConstant - If true, then instruction selection should 588 /// seek to shrink the FP constant of the specified type to a smaller type 589 /// in order to save space and / or reduce runtime. 590 virtual bool ShouldShrinkFPConstant(EVT VT) const { return true; } 591 592 /// hasTargetDAGCombine - If true, the target has custom DAG combine 593 /// transformations that it can perform for the specified node. 594 bool hasTargetDAGCombine(ISD::NodeType NT) const { 595 assert(unsigned(NT >> 3) < array_lengthof(TargetDAGCombineArray)); 596 return TargetDAGCombineArray[NT >> 3] & (1 << (NT&7)); 597 } 598 599 /// This function returns the maximum number of store operations permitted 600 /// to replace a call to llvm.memset. The value is set by the target at the 601 /// performance threshold for such a replacement. 602 /// @brief Get maximum # of store operations permitted for llvm.memset 603 unsigned getMaxStoresPerMemset() const { return maxStoresPerMemset; } 604 605 /// This function returns the maximum number of store operations permitted 606 /// to replace a call to llvm.memcpy. The value is set by the target at the 607 /// performance threshold for such a replacement. 608 /// @brief Get maximum # of store operations permitted for llvm.memcpy 609 unsigned getMaxStoresPerMemcpy() const { return maxStoresPerMemcpy; } 610 611 /// This function returns the maximum number of store operations permitted 612 /// to replace a call to llvm.memmove. The value is set by the target at the 613 /// performance threshold for such a replacement. 614 /// @brief Get maximum # of store operations permitted for llvm.memmove 615 unsigned getMaxStoresPerMemmove() const { return maxStoresPerMemmove; } 616 617 /// This function returns true if the target allows unaligned memory accesses. 618 /// of the specified type. This is used, for example, in situations where an 619 /// array copy/move/set is converted to a sequence of store operations. It's 620 /// use helps to ensure that such replacements don't generate code that causes 621 /// an alignment error (trap) on the target machine. 622 /// @brief Determine if the target supports unaligned memory accesses. 623 virtual bool allowsUnalignedMemoryAccesses(EVT VT) const { 624 return false; 625 } 626 627 /// This function returns true if the target would benefit from code placement 628 /// optimization. 629 /// @brief Determine if the target should perform code placement optimization. 630 bool shouldOptimizeCodePlacement() const { 631 return benefitFromCodePlacementOpt; 632 } 633 634 /// getOptimalMemOpType - Returns the target specific optimal type for load 635 /// and store operations as a result of memset, memcpy, and memmove 636 /// lowering. If DstAlign is zero that means it's safe to destination 637 /// alignment can satisfy any constraint. Similarly if SrcAlign is zero it 638 /// means there isn't a need to check it against alignment requirement, 639 /// probably because the source does not need to be loaded. If 640 /// 'NonScalarIntSafe' is true, that means it's safe to return a 641 /// non-scalar-integer type, e.g. empty string source, constant, or loaded 642 /// from memory. It returns EVT::Other if SelectionDAG should be responsible 643 /// for determining it. 644 virtual EVT getOptimalMemOpType(uint64_t Size, 645 unsigned DstAlign, unsigned SrcAlign, 646 bool NonScalarIntSafe, 647 SelectionDAG &DAG) const { 648 return MVT::Other; 649 } 650 651 /// usesUnderscoreSetJmp - Determine if we should use _setjmp or setjmp 652 /// to implement llvm.setjmp. 653 bool usesUnderscoreSetJmp() const { 654 return UseUnderscoreSetJmp; 655 } 656 657 /// usesUnderscoreLongJmp - Determine if we should use _longjmp or longjmp 658 /// to implement llvm.longjmp. 659 bool usesUnderscoreLongJmp() const { 660 return UseUnderscoreLongJmp; 661 } 662 663 /// getStackPointerRegisterToSaveRestore - If a physical register, this 664 /// specifies the register that llvm.savestack/llvm.restorestack should save 665 /// and restore. 666 unsigned getStackPointerRegisterToSaveRestore() const { 667 return StackPointerRegisterToSaveRestore; 668 } 669 670 /// getExceptionAddressRegister - If a physical register, this returns 671 /// the register that receives the exception address on entry to a landing 672 /// pad. 673 unsigned getExceptionAddressRegister() const { 674 return ExceptionPointerRegister; 675 } 676 677 /// getExceptionSelectorRegister - If a physical register, this returns 678 /// the register that receives the exception typeid on entry to a landing 679 /// pad. 680 unsigned getExceptionSelectorRegister() const { 681 return ExceptionSelectorRegister; 682 } 683 684 /// getJumpBufSize - returns the target's jmp_buf size in bytes (if never 685 /// set, the default is 200) 686 unsigned getJumpBufSize() const { 687 return JumpBufSize; 688 } 689 690 /// getJumpBufAlignment - returns the target's jmp_buf alignment in bytes 691 /// (if never set, the default is 0) 692 unsigned getJumpBufAlignment() const { 693 return JumpBufAlignment; 694 } 695 696 /// getIfCvtBlockLimit - returns the target specific if-conversion block size 697 /// limit. Any block whose size is greater should not be predicated. 698 unsigned getIfCvtBlockSizeLimit() const { 699 return IfCvtBlockSizeLimit; 700 } 701 702 /// getIfCvtDupBlockLimit - returns the target specific size limit for a 703 /// block to be considered for duplication. Any block whose size is greater 704 /// should not be duplicated to facilitate its predication. 705 unsigned getIfCvtDupBlockSizeLimit() const { 706 return IfCvtDupBlockSizeLimit; 707 } 708 709 /// getPrefLoopAlignment - return the preferred loop alignment. 710 /// 711 unsigned getPrefLoopAlignment() const { 712 return PrefLoopAlignment; 713 } 714 715 /// getPreIndexedAddressParts - returns true by value, base pointer and 716 /// offset pointer and addressing mode by reference if the node's address 717 /// can be legally represented as pre-indexed load / store address. 718 virtual bool getPreIndexedAddressParts(SDNode *N, SDValue &Base, 719 SDValue &Offset, 720 ISD::MemIndexedMode &AM, 721 SelectionDAG &DAG) const { 722 return false; 723 } 724 725 /// getPostIndexedAddressParts - returns true by value, base pointer and 726 /// offset pointer and addressing mode by reference if this node can be 727 /// combined with a load / store to form a post-indexed load / store. 728 virtual bool getPostIndexedAddressParts(SDNode *N, SDNode *Op, 729 SDValue &Base, SDValue &Offset, 730 ISD::MemIndexedMode &AM, 731 SelectionDAG &DAG) const { 732 return false; 733 } 734 735 /// getJumpTableEncoding - Return the entry encoding for a jump table in the 736 /// current function. The returned value is a member of the 737 /// MachineJumpTableInfo::JTEntryKind enum. 738 virtual unsigned getJumpTableEncoding() const; 739 740 virtual const MCExpr * 741 LowerCustomJumpTableEntry(const MachineJumpTableInfo *MJTI, 742 const MachineBasicBlock *MBB, unsigned uid, 743 MCContext &Ctx) const { 744 assert(0 && "Need to implement this hook if target has custom JTIs"); 745 return 0; 746 } 747 748 /// getPICJumpTableRelocaBase - Returns relocation base for the given PIC 749 /// jumptable. 750 virtual SDValue getPICJumpTableRelocBase(SDValue Table, 751 SelectionDAG &DAG) const; 752 753 /// getPICJumpTableRelocBaseExpr - This returns the relocation base for the 754 /// given PIC jumptable, the same as getPICJumpTableRelocBase, but as an 755 /// MCExpr. 756 virtual const MCExpr * 757 getPICJumpTableRelocBaseExpr(const MachineFunction *MF, 758 unsigned JTI, MCContext &Ctx) const; 759 760 /// isOffsetFoldingLegal - Return true if folding a constant offset 761 /// with the given GlobalAddress is legal. It is frequently not legal in 762 /// PIC relocation models. 763 virtual bool isOffsetFoldingLegal(const GlobalAddressSDNode *GA) const; 764 765 /// getFunctionAlignment - Return the Log2 alignment of this function. 766 virtual unsigned getFunctionAlignment(const Function *) const = 0; 767 768 //===--------------------------------------------------------------------===// 769 // TargetLowering Optimization Methods 770 // 771 772 /// TargetLoweringOpt - A convenience struct that encapsulates a DAG, and two 773 /// SDValues for returning information from TargetLowering to its clients 774 /// that want to combine 775 struct TargetLoweringOpt { 776 SelectionDAG &DAG; 777 bool ShrinkOps; 778 SDValue Old; 779 SDValue New; 780 781 explicit TargetLoweringOpt(SelectionDAG &InDAG, bool Shrink = false) : 782 DAG(InDAG), ShrinkOps(Shrink) {} 783 784 bool CombineTo(SDValue O, SDValue N) { 785 Old = O; 786 New = N; 787 return true; 788 } 789 790 /// ShrinkDemandedConstant - Check to see if the specified operand of the 791 /// specified instruction is a constant integer. If so, check to see if 792 /// there are any bits set in the constant that are not demanded. If so, 793 /// shrink the constant and return true. 794 bool ShrinkDemandedConstant(SDValue Op, const APInt &Demanded); 795 796 /// ShrinkDemandedOp - Convert x+y to (VT)((SmallVT)x+(SmallVT)y) if the 797 /// casts are free. This uses isZExtFree and ZERO_EXTEND for the widening 798 /// cast, but it could be generalized for targets with other types of 799 /// implicit widening casts. 800 bool ShrinkDemandedOp(SDValue Op, unsigned BitWidth, const APInt &Demanded, 801 DebugLoc dl); 802 }; 803 804 /// SimplifyDemandedBits - Look at Op. At this point, we know that only the 805 /// DemandedMask bits of the result of Op are ever used downstream. If we can 806 /// use this information to simplify Op, create a new simplified DAG node and 807 /// return true, returning the original and new nodes in Old and New. 808 /// Otherwise, analyze the expression and return a mask of KnownOne and 809 /// KnownZero bits for the expression (used to simplify the caller). 810 /// The KnownZero/One bits may only be accurate for those bits in the 811 /// DemandedMask. 812 bool SimplifyDemandedBits(SDValue Op, const APInt &DemandedMask, 813 APInt &KnownZero, APInt &KnownOne, 814 TargetLoweringOpt &TLO, unsigned Depth = 0) const; 815 816 /// computeMaskedBitsForTargetNode - Determine which of the bits specified in 817 /// Mask are known to be either zero or one and return them in the 818 /// KnownZero/KnownOne bitsets. 819 virtual void computeMaskedBitsForTargetNode(const SDValue Op, 820 const APInt &Mask, 821 APInt &KnownZero, 822 APInt &KnownOne, 823 const SelectionDAG &DAG, 824 unsigned Depth = 0) const; 825 826 /// ComputeNumSignBitsForTargetNode - This method can be implemented by 827 /// targets that want to expose additional information about sign bits to the 828 /// DAG Combiner. 829 virtual unsigned ComputeNumSignBitsForTargetNode(SDValue Op, 830 unsigned Depth = 0) const; 831 832 struct DAGCombinerInfo { 833 void *DC; // The DAG Combiner object. 834 bool BeforeLegalize; 835 bool BeforeLegalizeOps; 836 bool CalledByLegalizer; 837 public: 838 SelectionDAG &DAG; 839 840 DAGCombinerInfo(SelectionDAG &dag, bool bl, bool blo, bool cl, void *dc) 841 : DC(dc), BeforeLegalize(bl), BeforeLegalizeOps(blo), 842 CalledByLegalizer(cl), DAG(dag) {} 843 844 bool isBeforeLegalize() const { return BeforeLegalize; } 845 bool isBeforeLegalizeOps() const { return BeforeLegalizeOps; } 846 bool isCalledByLegalizer() const { return CalledByLegalizer; } 847 848 void AddToWorklist(SDNode *N); 849 SDValue CombineTo(SDNode *N, const std::vector<SDValue> &To, 850 bool AddTo = true); 851 SDValue CombineTo(SDNode *N, SDValue Res, bool AddTo = true); 852 SDValue CombineTo(SDNode *N, SDValue Res0, SDValue Res1, bool AddTo = true); 853 854 void CommitTargetLoweringOpt(const TargetLoweringOpt &TLO); 855 }; 856 857 /// SimplifySetCC - Try to simplify a setcc built with the specified operands 858 /// and cc. If it is unable to simplify it, return a null SDValue. 859 SDValue SimplifySetCC(EVT VT, SDValue N0, SDValue N1, 860 ISD::CondCode Cond, bool foldBooleans, 861 DAGCombinerInfo &DCI, DebugLoc dl) const; 862 863 /// isGAPlusOffset - Returns true (and the GlobalValue and the offset) if the 864 /// node is a GlobalAddress + offset. 865 virtual bool 866 isGAPlusOffset(SDNode *N, GlobalValue* &GA, int64_t &Offset) const; 867 868 /// PerformDAGCombine - This method will be invoked for all target nodes and 869 /// for any target-independent nodes that the target has registered with 870 /// invoke it for. 871 /// 872 /// The semantics are as follows: 873 /// Return Value: 874 /// SDValue.Val == 0 - No change was made 875 /// SDValue.Val == N - N was replaced, is dead, and is already handled. 876 /// otherwise - N should be replaced by the returned Operand. 877 /// 878 /// In addition, methods provided by DAGCombinerInfo may be used to perform 879 /// more complex transformations. 880 /// 881 virtual SDValue PerformDAGCombine(SDNode *N, DAGCombinerInfo &DCI) const; 882 883 //===--------------------------------------------------------------------===// 884 // TargetLowering Configuration Methods - These methods should be invoked by 885 // the derived class constructor to configure this object for the target. 886 // 887 888protected: 889 /// setShiftAmountType - Describe the type that should be used for shift 890 /// amounts. This type defaults to the pointer type. 891 void setShiftAmountType(MVT VT) { ShiftAmountTy = VT; } 892 893 /// setBooleanContents - Specify how the target extends the result of a 894 /// boolean value from i1 to a wider type. See getBooleanContents. 895 void setBooleanContents(BooleanContent Ty) { BooleanContents = Ty; } 896 897 /// setSchedulingPreference - Specify the target scheduling preference. 898 void setSchedulingPreference(SchedPreference Pref) { 899 SchedPreferenceInfo = Pref; 900 } 901 902 /// setUseUnderscoreSetJmp - Indicate whether this target prefers to 903 /// use _setjmp to implement llvm.setjmp or the non _ version. 904 /// Defaults to false. 905 void setUseUnderscoreSetJmp(bool Val) { 906 UseUnderscoreSetJmp = Val; 907 } 908 909 /// setUseUnderscoreLongJmp - Indicate whether this target prefers to 910 /// use _longjmp to implement llvm.longjmp or the non _ version. 911 /// Defaults to false. 912 void setUseUnderscoreLongJmp(bool Val) { 913 UseUnderscoreLongJmp = Val; 914 } 915 916 /// setStackPointerRegisterToSaveRestore - If set to a physical register, this 917 /// specifies the register that llvm.savestack/llvm.restorestack should save 918 /// and restore. 919 void setStackPointerRegisterToSaveRestore(unsigned R) { 920 StackPointerRegisterToSaveRestore = R; 921 } 922 923 /// setExceptionPointerRegister - If set to a physical register, this sets 924 /// the register that receives the exception address on entry to a landing 925 /// pad. 926 void setExceptionPointerRegister(unsigned R) { 927 ExceptionPointerRegister = R; 928 } 929 930 /// setExceptionSelectorRegister - If set to a physical register, this sets 931 /// the register that receives the exception typeid on entry to a landing 932 /// pad. 933 void setExceptionSelectorRegister(unsigned R) { 934 ExceptionSelectorRegister = R; 935 } 936 937 /// SelectIsExpensive - Tells the code generator not to expand operations 938 /// into sequences that use the select operations if possible. 939 void setSelectIsExpensive() { SelectIsExpensive = true; } 940 941 /// setIntDivIsCheap - Tells the code generator that integer divide is 942 /// expensive, and if possible, should be replaced by an alternate sequence 943 /// of instructions not containing an integer divide. 944 void setIntDivIsCheap(bool isCheap = true) { IntDivIsCheap = isCheap; } 945 946 /// setPow2DivIsCheap - Tells the code generator that it shouldn't generate 947 /// srl/add/sra for a signed divide by power of two, and let the target handle 948 /// it. 949 void setPow2DivIsCheap(bool isCheap = true) { Pow2DivIsCheap = isCheap; } 950 951 /// addRegisterClass - Add the specified register class as an available 952 /// regclass for the specified value type. This indicates the selector can 953 /// handle values of that class natively. 954 void addRegisterClass(EVT VT, TargetRegisterClass *RC) { 955 assert((unsigned)VT.getSimpleVT().SimpleTy < array_lengthof(RegClassForVT)); 956 AvailableRegClasses.push_back(std::make_pair(VT, RC)); 957 RegClassForVT[VT.getSimpleVT().SimpleTy] = RC; 958 } 959 960 /// computeRegisterProperties - Once all of the register classes are added, 961 /// this allows us to compute derived properties we expose. 962 void computeRegisterProperties(); 963 964 /// setOperationAction - Indicate that the specified operation does not work 965 /// with the specified type and indicate what to do about it. 966 void setOperationAction(unsigned Op, MVT VT, 967 LegalizeAction Action) { 968 unsigned I = (unsigned)VT.SimpleTy; 969 unsigned J = I & 31; 970 I = I >> 5; 971 OpActions[I][Op] &= ~(uint64_t(3UL) << (J*2)); 972 OpActions[I][Op] |= (uint64_t)Action << (J*2); 973 } 974 975 /// setLoadExtAction - Indicate that the specified load with extension does 976 /// not work with the specified type and indicate what to do about it. 977 void setLoadExtAction(unsigned ExtType, MVT VT, 978 LegalizeAction Action) { 979 assert((unsigned)VT.SimpleTy*2 < 63 && 980 ExtType < array_lengthof(LoadExtActions) && 981 "Table isn't big enough!"); 982 LoadExtActions[ExtType] &= ~(uint64_t(3UL) << VT.SimpleTy*2); 983 LoadExtActions[ExtType] |= (uint64_t)Action << VT.SimpleTy*2; 984 } 985 986 /// setTruncStoreAction - Indicate that the specified truncating store does 987 /// not work with the specified type and indicate what to do about it. 988 void setTruncStoreAction(MVT ValVT, MVT MemVT, 989 LegalizeAction Action) { 990 assert((unsigned)ValVT.SimpleTy < array_lengthof(TruncStoreActions) && 991 (unsigned)MemVT.SimpleTy*2 < 63 && 992 "Table isn't big enough!"); 993 TruncStoreActions[ValVT.SimpleTy] &= ~(uint64_t(3UL) << MemVT.SimpleTy*2); 994 TruncStoreActions[ValVT.SimpleTy] |= (uint64_t)Action << MemVT.SimpleTy*2; 995 } 996 997 /// setIndexedLoadAction - Indicate that the specified indexed load does or 998 /// does not work with the specified type and indicate what to do abort 999 /// it. NOTE: All indexed mode loads are initialized to Expand in 1000 /// TargetLowering.cpp 1001 void setIndexedLoadAction(unsigned IdxMode, MVT VT, 1002 LegalizeAction Action) { 1003 assert((unsigned)VT.SimpleTy < MVT::LAST_VALUETYPE && 1004 IdxMode < array_lengthof(IndexedModeActions[0][0]) && 1005 "Table isn't big enough!"); 1006 IndexedModeActions[(unsigned)VT.SimpleTy][0][IdxMode] = (uint8_t)Action; 1007 } 1008 1009 /// setIndexedStoreAction - Indicate that the specified indexed store does or 1010 /// does not work with the specified type and indicate what to do about 1011 /// it. NOTE: All indexed mode stores are initialized to Expand in 1012 /// TargetLowering.cpp 1013 void setIndexedStoreAction(unsigned IdxMode, MVT VT, 1014 LegalizeAction Action) { 1015 assert((unsigned)VT.SimpleTy < MVT::LAST_VALUETYPE && 1016 IdxMode < array_lengthof(IndexedModeActions[0][1] ) && 1017 "Table isn't big enough!"); 1018 IndexedModeActions[(unsigned)VT.SimpleTy][1][IdxMode] = (uint8_t)Action; 1019 } 1020 1021 /// setCondCodeAction - Indicate that the specified condition code is or isn't 1022 /// supported on the target and indicate what to do about it. 1023 void setCondCodeAction(ISD::CondCode CC, MVT VT, 1024 LegalizeAction Action) { 1025 assert((unsigned)VT.SimpleTy < MVT::LAST_VALUETYPE && 1026 (unsigned)CC < array_lengthof(CondCodeActions) && 1027 "Table isn't big enough!"); 1028 CondCodeActions[(unsigned)CC] &= ~(uint64_t(3UL) << VT.SimpleTy*2); 1029 CondCodeActions[(unsigned)CC] |= (uint64_t)Action << VT.SimpleTy*2; 1030 } 1031 1032 /// AddPromotedToType - If Opc/OrigVT is specified as being promoted, the 1033 /// promotion code defaults to trying a larger integer/fp until it can find 1034 /// one that works. If that default is insufficient, this method can be used 1035 /// by the target to override the default. 1036 void AddPromotedToType(unsigned Opc, MVT OrigVT, MVT DestVT) { 1037 PromoteToType[std::make_pair(Opc, OrigVT.SimpleTy)] = DestVT.SimpleTy; 1038 } 1039 1040 /// setTargetDAGCombine - Targets should invoke this method for each target 1041 /// independent node that they want to provide a custom DAG combiner for by 1042 /// implementing the PerformDAGCombine virtual method. 1043 void setTargetDAGCombine(ISD::NodeType NT) { 1044 assert(unsigned(NT >> 3) < array_lengthof(TargetDAGCombineArray)); 1045 TargetDAGCombineArray[NT >> 3] |= 1 << (NT&7); 1046 } 1047 1048 /// setJumpBufSize - Set the target's required jmp_buf buffer size (in 1049 /// bytes); default is 200 1050 void setJumpBufSize(unsigned Size) { 1051 JumpBufSize = Size; 1052 } 1053 1054 /// setJumpBufAlignment - Set the target's required jmp_buf buffer 1055 /// alignment (in bytes); default is 0 1056 void setJumpBufAlignment(unsigned Align) { 1057 JumpBufAlignment = Align; 1058 } 1059 1060 /// setIfCvtBlockSizeLimit - Set the target's if-conversion block size 1061 /// limit (in number of instructions); default is 2. 1062 void setIfCvtBlockSizeLimit(unsigned Limit) { 1063 IfCvtBlockSizeLimit = Limit; 1064 } 1065 1066 /// setIfCvtDupBlockSizeLimit - Set the target's block size limit (in number 1067 /// of instructions) to be considered for code duplication during 1068 /// if-conversion; default is 2. 1069 void setIfCvtDupBlockSizeLimit(unsigned Limit) { 1070 IfCvtDupBlockSizeLimit = Limit; 1071 } 1072 1073 /// setPrefLoopAlignment - Set the target's preferred loop alignment. Default 1074 /// alignment is zero, it means the target does not care about loop alignment. 1075 void setPrefLoopAlignment(unsigned Align) { 1076 PrefLoopAlignment = Align; 1077 } 1078 1079public: 1080 1081 virtual const TargetSubtarget *getSubtarget() { 1082 assert(0 && "Not Implemented"); 1083 return NULL; // this is here to silence compiler errors 1084 } 1085 1086 //===--------------------------------------------------------------------===// 1087 // Lowering methods - These methods must be implemented by targets so that 1088 // the SelectionDAGLowering code knows how to lower these. 1089 // 1090 1091 /// LowerFormalArguments - This hook must be implemented to lower the 1092 /// incoming (formal) arguments, described by the Ins array, into the 1093 /// specified DAG. The implementation should fill in the InVals array 1094 /// with legal-type argument values, and return the resulting token 1095 /// chain value. 1096 /// 1097 virtual SDValue 1098 LowerFormalArguments(SDValue Chain, 1099 CallingConv::ID CallConv, bool isVarArg, 1100 const SmallVectorImpl<ISD::InputArg> &Ins, 1101 DebugLoc dl, SelectionDAG &DAG, 1102 SmallVectorImpl<SDValue> &InVals) { 1103 assert(0 && "Not Implemented"); 1104 return SDValue(); // this is here to silence compiler errors 1105 } 1106 1107 /// LowerCallTo - This function lowers an abstract call to a function into an 1108 /// actual call. This returns a pair of operands. The first element is the 1109 /// return value for the function (if RetTy is not VoidTy). The second 1110 /// element is the outgoing token chain. It calls LowerCall to do the actual 1111 /// lowering. 1112 struct ArgListEntry { 1113 SDValue Node; 1114 const Type* Ty; 1115 bool isSExt : 1; 1116 bool isZExt : 1; 1117 bool isInReg : 1; 1118 bool isSRet : 1; 1119 bool isNest : 1; 1120 bool isByVal : 1; 1121 uint16_t Alignment; 1122 1123 ArgListEntry() : isSExt(false), isZExt(false), isInReg(false), 1124 isSRet(false), isNest(false), isByVal(false), Alignment(0) { } 1125 }; 1126 typedef std::vector<ArgListEntry> ArgListTy; 1127 std::pair<SDValue, SDValue> 1128 LowerCallTo(SDValue Chain, const Type *RetTy, bool RetSExt, bool RetZExt, 1129 bool isVarArg, bool isInreg, unsigned NumFixedArgs, 1130 CallingConv::ID CallConv, bool isTailCall, 1131 bool isReturnValueUsed, SDValue Callee, ArgListTy &Args, 1132 SelectionDAG &DAG, DebugLoc dl); 1133 1134 /// LowerCall - This hook must be implemented to lower calls into the 1135 /// the specified DAG. The outgoing arguments to the call are described 1136 /// by the Outs array, and the values to be returned by the call are 1137 /// described by the Ins array. The implementation should fill in the 1138 /// InVals array with legal-type return values from the call, and return 1139 /// the resulting token chain value. 1140 virtual SDValue 1141 LowerCall(SDValue Chain, SDValue Callee, 1142 CallingConv::ID CallConv, bool isVarArg, bool &isTailCall, 1143 const SmallVectorImpl<ISD::OutputArg> &Outs, 1144 const SmallVectorImpl<ISD::InputArg> &Ins, 1145 DebugLoc dl, SelectionDAG &DAG, 1146 SmallVectorImpl<SDValue> &InVals) { 1147 assert(0 && "Not Implemented"); 1148 return SDValue(); // this is here to silence compiler errors 1149 } 1150 1151 /// CanLowerReturn - This hook should be implemented to check whether the 1152 /// return values described by the Outs array can fit into the return 1153 /// registers. If false is returned, an sret-demotion is performed. 1154 /// 1155 virtual bool CanLowerReturn(CallingConv::ID CallConv, bool isVarArg, 1156 const SmallVectorImpl<EVT> &OutTys, 1157 const SmallVectorImpl<ISD::ArgFlagsTy> &ArgsFlags, 1158 SelectionDAG &DAG) 1159 { 1160 // Return true by default to get preexisting behavior. 1161 return true; 1162 } 1163 /// LowerReturn - This hook must be implemented to lower outgoing 1164 /// return values, described by the Outs array, into the specified 1165 /// DAG. The implementation should return the resulting token chain 1166 /// value. 1167 /// 1168 virtual SDValue 1169 LowerReturn(SDValue Chain, CallingConv::ID CallConv, bool isVarArg, 1170 const SmallVectorImpl<ISD::OutputArg> &Outs, 1171 DebugLoc dl, SelectionDAG &DAG) { 1172 assert(0 && "Not Implemented"); 1173 return SDValue(); // this is here to silence compiler errors 1174 } 1175 1176 /// EmitTargetCodeForMemcpy - Emit target-specific code that performs a 1177 /// memcpy. This can be used by targets to provide code sequences for cases 1178 /// that don't fit the target's parameters for simple loads/stores and can be 1179 /// more efficient than using a library call. This function can return a null 1180 /// SDValue if the target declines to use custom code and a different 1181 /// lowering strategy should be used. 1182 /// 1183 /// If AlwaysInline is true, the size is constant and the target should not 1184 /// emit any calls and is strongly encouraged to attempt to emit inline code 1185 /// even if it is beyond the usual threshold because this intrinsic is being 1186 /// expanded in a place where calls are not feasible (e.g. within the prologue 1187 /// for another call). If the target chooses to decline an AlwaysInline 1188 /// request here, legalize will resort to using simple loads and stores. 1189 virtual SDValue 1190 EmitTargetCodeForMemcpy(SelectionDAG &DAG, DebugLoc dl, 1191 SDValue Chain, 1192 SDValue Op1, SDValue Op2, 1193 SDValue Op3, unsigned Align, bool isVolatile, 1194 bool AlwaysInline, 1195 const Value *DstSV, uint64_t DstOff, 1196 const Value *SrcSV, uint64_t SrcOff) { 1197 return SDValue(); 1198 } 1199 1200 /// EmitTargetCodeForMemmove - Emit target-specific code that performs a 1201 /// memmove. This can be used by targets to provide code sequences for cases 1202 /// that don't fit the target's parameters for simple loads/stores and can be 1203 /// more efficient than using a library call. This function can return a null 1204 /// SDValue if the target declines to use custom code and a different 1205 /// lowering strategy should be used. 1206 virtual SDValue 1207 EmitTargetCodeForMemmove(SelectionDAG &DAG, DebugLoc dl, 1208 SDValue Chain, 1209 SDValue Op1, SDValue Op2, 1210 SDValue Op3, unsigned Align, bool isVolatile, 1211 const Value *DstSV, uint64_t DstOff, 1212 const Value *SrcSV, uint64_t SrcOff) { 1213 return SDValue(); 1214 } 1215 1216 /// EmitTargetCodeForMemset - Emit target-specific code that performs a 1217 /// memset. This can be used by targets to provide code sequences for cases 1218 /// that don't fit the target's parameters for simple stores and can be more 1219 /// efficient than using a library call. This function can return a null 1220 /// SDValue if the target declines to use custom code and a different 1221 /// lowering strategy should be used. 1222 virtual SDValue 1223 EmitTargetCodeForMemset(SelectionDAG &DAG, DebugLoc dl, 1224 SDValue Chain, 1225 SDValue Op1, SDValue Op2, 1226 SDValue Op3, unsigned Align, bool isVolatile, 1227 const Value *DstSV, uint64_t DstOff) { 1228 return SDValue(); 1229 } 1230 1231 /// LowerOperationWrapper - This callback is invoked by the type legalizer 1232 /// to legalize nodes with an illegal operand type but legal result types. 1233 /// It replaces the LowerOperation callback in the type Legalizer. 1234 /// The reason we can not do away with LowerOperation entirely is that 1235 /// LegalizeDAG isn't yet ready to use this callback. 1236 /// TODO: Consider merging with ReplaceNodeResults. 1237 1238 /// The target places new result values for the node in Results (their number 1239 /// and types must exactly match those of the original return values of 1240 /// the node), or leaves Results empty, which indicates that the node is not 1241 /// to be custom lowered after all. 1242 /// The default implementation calls LowerOperation. 1243 virtual void LowerOperationWrapper(SDNode *N, 1244 SmallVectorImpl<SDValue> &Results, 1245 SelectionDAG &DAG); 1246 1247 /// LowerOperation - This callback is invoked for operations that are 1248 /// unsupported by the target, which are registered to use 'custom' lowering, 1249 /// and whose defined values are all legal. 1250 /// If the target has no operations that require custom lowering, it need not 1251 /// implement this. The default implementation of this aborts. 1252 virtual SDValue LowerOperation(SDValue Op, SelectionDAG &DAG); 1253 1254 /// ReplaceNodeResults - This callback is invoked when a node result type is 1255 /// illegal for the target, and the operation was registered to use 'custom' 1256 /// lowering for that result type. The target places new result values for 1257 /// the node in Results (their number and types must exactly match those of 1258 /// the original return values of the node), or leaves Results empty, which 1259 /// indicates that the node is not to be custom lowered after all. 1260 /// 1261 /// If the target has no operations that require custom lowering, it need not 1262 /// implement this. The default implementation aborts. 1263 virtual void ReplaceNodeResults(SDNode *N, SmallVectorImpl<SDValue> &Results, 1264 SelectionDAG &DAG) { 1265 assert(0 && "ReplaceNodeResults not implemented for this target!"); 1266 } 1267 1268 /// getTargetNodeName() - This method returns the name of a target specific 1269 /// DAG node. 1270 virtual const char *getTargetNodeName(unsigned Opcode) const; 1271 1272 /// createFastISel - This method returns a target specific FastISel object, 1273 /// or null if the target does not support "fast" ISel. 1274 virtual FastISel * 1275 createFastISel(MachineFunction &, MachineModuleInfo *, 1276 DenseMap<const Value *, unsigned> &, 1277 DenseMap<const BasicBlock *, MachineBasicBlock *> &, 1278 DenseMap<const AllocaInst *, int> & 1279#ifndef NDEBUG 1280 , SmallSet<Instruction*, 8> &CatchInfoLost 1281#endif 1282 ) { 1283 return 0; 1284 } 1285 1286 //===--------------------------------------------------------------------===// 1287 // Inline Asm Support hooks 1288 // 1289 1290 /// ExpandInlineAsm - This hook allows the target to expand an inline asm 1291 /// call to be explicit llvm code if it wants to. This is useful for 1292 /// turning simple inline asms into LLVM intrinsics, which gives the 1293 /// compiler more information about the behavior of the code. 1294 virtual bool ExpandInlineAsm(CallInst *CI) const { 1295 return false; 1296 } 1297 1298 enum ConstraintType { 1299 C_Register, // Constraint represents specific register(s). 1300 C_RegisterClass, // Constraint represents any of register(s) in class. 1301 C_Memory, // Memory constraint. 1302 C_Other, // Something else. 1303 C_Unknown // Unsupported constraint. 1304 }; 1305 1306 /// AsmOperandInfo - This contains information for each constraint that we are 1307 /// lowering. 1308 struct AsmOperandInfo : public InlineAsm::ConstraintInfo { 1309 /// ConstraintCode - This contains the actual string for the code, like "m". 1310 /// TargetLowering picks the 'best' code from ConstraintInfo::Codes that 1311 /// most closely matches the operand. 1312 std::string ConstraintCode; 1313 1314 /// ConstraintType - Information about the constraint code, e.g. Register, 1315 /// RegisterClass, Memory, Other, Unknown. 1316 TargetLowering::ConstraintType ConstraintType; 1317 1318 /// CallOperandval - If this is the result output operand or a 1319 /// clobber, this is null, otherwise it is the incoming operand to the 1320 /// CallInst. This gets modified as the asm is processed. 1321 Value *CallOperandVal; 1322 1323 /// ConstraintVT - The ValueType for the operand value. 1324 EVT ConstraintVT; 1325 1326 /// isMatchingInputConstraint - Return true of this is an input operand that 1327 /// is a matching constraint like "4". 1328 bool isMatchingInputConstraint() const; 1329 1330 /// getMatchedOperand - If this is an input matching constraint, this method 1331 /// returns the output operand it matches. 1332 unsigned getMatchedOperand() const; 1333 1334 AsmOperandInfo(const InlineAsm::ConstraintInfo &info) 1335 : InlineAsm::ConstraintInfo(info), 1336 ConstraintType(TargetLowering::C_Unknown), 1337 CallOperandVal(0), ConstraintVT(MVT::Other) { 1338 } 1339 }; 1340 1341 /// ComputeConstraintToUse - Determines the constraint code and constraint 1342 /// type to use for the specific AsmOperandInfo, setting 1343 /// OpInfo.ConstraintCode and OpInfo.ConstraintType. If the actual operand 1344 /// being passed in is available, it can be passed in as Op, otherwise an 1345 /// empty SDValue can be passed. If hasMemory is true it means one of the asm 1346 /// constraint of the inline asm instruction being processed is 'm'. 1347 virtual void ComputeConstraintToUse(AsmOperandInfo &OpInfo, 1348 SDValue Op, 1349 bool hasMemory, 1350 SelectionDAG *DAG = 0) const; 1351 1352 /// getConstraintType - Given a constraint, return the type of constraint it 1353 /// is for this target. 1354 virtual ConstraintType getConstraintType(const std::string &Constraint) const; 1355 1356 /// getRegClassForInlineAsmConstraint - Given a constraint letter (e.g. "r"), 1357 /// return a list of registers that can be used to satisfy the constraint. 1358 /// This should only be used for C_RegisterClass constraints. 1359 virtual std::vector<unsigned> 1360 getRegClassForInlineAsmConstraint(const std::string &Constraint, 1361 EVT VT) const; 1362 1363 /// getRegForInlineAsmConstraint - Given a physical register constraint (e.g. 1364 /// {edx}), return the register number and the register class for the 1365 /// register. 1366 /// 1367 /// Given a register class constraint, like 'r', if this corresponds directly 1368 /// to an LLVM register class, return a register of 0 and the register class 1369 /// pointer. 1370 /// 1371 /// This should only be used for C_Register constraints. On error, 1372 /// this returns a register number of 0 and a null register class pointer.. 1373 virtual std::pair<unsigned, const TargetRegisterClass*> 1374 getRegForInlineAsmConstraint(const std::string &Constraint, 1375 EVT VT) const; 1376 1377 /// LowerXConstraint - try to replace an X constraint, which matches anything, 1378 /// with another that has more specific requirements based on the type of the 1379 /// corresponding operand. This returns null if there is no replacement to 1380 /// make. 1381 virtual const char *LowerXConstraint(EVT ConstraintVT) const; 1382 1383 /// LowerAsmOperandForConstraint - Lower the specified operand into the Ops 1384 /// vector. If it is invalid, don't add anything to Ops. If hasMemory is true 1385 /// it means one of the asm constraint of the inline asm instruction being 1386 /// processed is 'm'. 1387 virtual void LowerAsmOperandForConstraint(SDValue Op, char ConstraintLetter, 1388 bool hasMemory, 1389 std::vector<SDValue> &Ops, 1390 SelectionDAG &DAG) const; 1391 1392 //===--------------------------------------------------------------------===// 1393 // Instruction Emitting Hooks 1394 // 1395 1396 // EmitInstrWithCustomInserter - This method should be implemented by targets 1397 // that mark instructions with the 'usesCustomInserter' flag. These 1398 // instructions are special in various ways, which require special support to 1399 // insert. The specified MachineInstr is created but not inserted into any 1400 // basic blocks, and this method is called to expand it into a sequence of 1401 // instructions, potentially also creating new basic blocks and control flow. 1402 // When new basic blocks are inserted and the edges from MBB to its successors 1403 // are modified, the method should insert pairs of <OldSucc, NewSucc> into the 1404 // DenseMap. 1405 virtual MachineBasicBlock *EmitInstrWithCustomInserter(MachineInstr *MI, 1406 MachineBasicBlock *MBB, 1407 DenseMap<MachineBasicBlock*, MachineBasicBlock*> *EM) const; 1408 1409 //===--------------------------------------------------------------------===// 1410 // Addressing mode description hooks (used by LSR etc). 1411 // 1412 1413 /// AddrMode - This represents an addressing mode of: 1414 /// BaseGV + BaseOffs + BaseReg + Scale*ScaleReg 1415 /// If BaseGV is null, there is no BaseGV. 1416 /// If BaseOffs is zero, there is no base offset. 1417 /// If HasBaseReg is false, there is no base register. 1418 /// If Scale is zero, there is no ScaleReg. Scale of 1 indicates a reg with 1419 /// no scale. 1420 /// 1421 struct AddrMode { 1422 GlobalValue *BaseGV; 1423 int64_t BaseOffs; 1424 bool HasBaseReg; 1425 int64_t Scale; 1426 AddrMode() : BaseGV(0), BaseOffs(0), HasBaseReg(false), Scale(0) {} 1427 }; 1428 1429 /// isLegalAddressingMode - Return true if the addressing mode represented by 1430 /// AM is legal for this target, for a load/store of the specified type. 1431 /// The type may be VoidTy, in which case only return true if the addressing 1432 /// mode is legal for a load/store of any legal type. 1433 /// TODO: Handle pre/postinc as well. 1434 virtual bool isLegalAddressingMode(const AddrMode &AM, const Type *Ty) const; 1435 1436 /// isTruncateFree - Return true if it's free to truncate a value of 1437 /// type Ty1 to type Ty2. e.g. On x86 it's free to truncate a i32 value in 1438 /// register EAX to i16 by referencing its sub-register AX. 1439 virtual bool isTruncateFree(const Type *Ty1, const Type *Ty2) const { 1440 return false; 1441 } 1442 1443 virtual bool isTruncateFree(EVT VT1, EVT VT2) const { 1444 return false; 1445 } 1446 1447 /// isZExtFree - Return true if any actual instruction that defines a 1448 /// value of type Ty1 implicitly zero-extends the value to Ty2 in the result 1449 /// register. This does not necessarily include registers defined in 1450 /// unknown ways, such as incoming arguments, or copies from unknown 1451 /// virtual registers. Also, if isTruncateFree(Ty2, Ty1) is true, this 1452 /// does not necessarily apply to truncate instructions. e.g. on x86-64, 1453 /// all instructions that define 32-bit values implicit zero-extend the 1454 /// result out to 64 bits. 1455 virtual bool isZExtFree(const Type *Ty1, const Type *Ty2) const { 1456 return false; 1457 } 1458 1459 virtual bool isZExtFree(EVT VT1, EVT VT2) const { 1460 return false; 1461 } 1462 1463 /// isNarrowingProfitable - Return true if it's profitable to narrow 1464 /// operations of type VT1 to VT2. e.g. on x86, it's profitable to narrow 1465 /// from i32 to i8 but not from i32 to i16. 1466 virtual bool isNarrowingProfitable(EVT VT1, EVT VT2) const { 1467 return false; 1468 } 1469 1470 /// isLegalICmpImmediate - Return true if the specified immediate is legal 1471 /// icmp immediate, that is the target has icmp instructions which can compare 1472 /// a register against the immediate without having to materialize the 1473 /// immediate into a register. 1474 virtual bool isLegalICmpImmediate(int64_t Imm) const { 1475 return true; 1476 } 1477 1478 //===--------------------------------------------------------------------===// 1479 // Div utility functions 1480 // 1481 SDValue BuildSDIV(SDNode *N, SelectionDAG &DAG, 1482 std::vector<SDNode*>* Created) const; 1483 SDValue BuildUDIV(SDNode *N, SelectionDAG &DAG, 1484 std::vector<SDNode*>* Created) const; 1485 1486 1487 //===--------------------------------------------------------------------===// 1488 // Runtime Library hooks 1489 // 1490 1491 /// setLibcallName - Rename the default libcall routine name for the specified 1492 /// libcall. 1493 void setLibcallName(RTLIB::Libcall Call, const char *Name) { 1494 LibcallRoutineNames[Call] = Name; 1495 } 1496 1497 /// getLibcallName - Get the libcall routine name for the specified libcall. 1498 /// 1499 const char *getLibcallName(RTLIB::Libcall Call) const { 1500 return LibcallRoutineNames[Call]; 1501 } 1502 1503 /// setCmpLibcallCC - Override the default CondCode to be used to test the 1504 /// result of the comparison libcall against zero. 1505 void setCmpLibcallCC(RTLIB::Libcall Call, ISD::CondCode CC) { 1506 CmpLibcallCCs[Call] = CC; 1507 } 1508 1509 /// getCmpLibcallCC - Get the CondCode that's to be used to test the result of 1510 /// the comparison libcall against zero. 1511 ISD::CondCode getCmpLibcallCC(RTLIB::Libcall Call) const { 1512 return CmpLibcallCCs[Call]; 1513 } 1514 1515 /// setLibcallCallingConv - Set the CallingConv that should be used for the 1516 /// specified libcall. 1517 void setLibcallCallingConv(RTLIB::Libcall Call, CallingConv::ID CC) { 1518 LibcallCallingConvs[Call] = CC; 1519 } 1520 1521 /// getLibcallCallingConv - Get the CallingConv that should be used for the 1522 /// specified libcall. 1523 CallingConv::ID getLibcallCallingConv(RTLIB::Libcall Call) const { 1524 return LibcallCallingConvs[Call]; 1525 } 1526 1527private: 1528 TargetMachine &TM; 1529 const TargetData *TD; 1530 TargetLoweringObjectFile &TLOF; 1531 1532 /// PointerTy - The type to use for pointers, usually i32 or i64. 1533 /// 1534 MVT PointerTy; 1535 1536 /// IsLittleEndian - True if this is a little endian target. 1537 /// 1538 bool IsLittleEndian; 1539 1540 /// SelectIsExpensive - Tells the code generator not to expand operations 1541 /// into sequences that use the select operations if possible. 1542 bool SelectIsExpensive; 1543 1544 /// IntDivIsCheap - Tells the code generator not to expand integer divides by 1545 /// constants into a sequence of muls, adds, and shifts. This is a hack until 1546 /// a real cost model is in place. If we ever optimize for size, this will be 1547 /// set to true unconditionally. 1548 bool IntDivIsCheap; 1549 1550 /// Pow2DivIsCheap - Tells the code generator that it shouldn't generate 1551 /// srl/add/sra for a signed divide by power of two, and let the target handle 1552 /// it. 1553 bool Pow2DivIsCheap; 1554 1555 /// UseUnderscoreSetJmp - This target prefers to use _setjmp to implement 1556 /// llvm.setjmp. Defaults to false. 1557 bool UseUnderscoreSetJmp; 1558 1559 /// UseUnderscoreLongJmp - This target prefers to use _longjmp to implement 1560 /// llvm.longjmp. Defaults to false. 1561 bool UseUnderscoreLongJmp; 1562 1563 /// ShiftAmountTy - The type to use for shift amounts, usually i8 or whatever 1564 /// PointerTy is. 1565 MVT ShiftAmountTy; 1566 1567 /// BooleanContents - Information about the contents of the high-bits in 1568 /// boolean values held in a type wider than i1. See getBooleanContents. 1569 BooleanContent BooleanContents; 1570 1571 /// SchedPreferenceInfo - The target scheduling preference: shortest possible 1572 /// total cycles or lowest register usage. 1573 SchedPreference SchedPreferenceInfo; 1574 1575 /// JumpBufSize - The size, in bytes, of the target's jmp_buf buffers 1576 unsigned JumpBufSize; 1577 1578 /// JumpBufAlignment - The alignment, in bytes, of the target's jmp_buf 1579 /// buffers 1580 unsigned JumpBufAlignment; 1581 1582 /// IfCvtBlockSizeLimit - The maximum allowed size for a block to be 1583 /// if-converted. 1584 unsigned IfCvtBlockSizeLimit; 1585 1586 /// IfCvtDupBlockSizeLimit - The maximum allowed size for a block to be 1587 /// duplicated during if-conversion. 1588 unsigned IfCvtDupBlockSizeLimit; 1589 1590 /// PrefLoopAlignment - The perferred loop alignment. 1591 /// 1592 unsigned PrefLoopAlignment; 1593 1594 /// StackPointerRegisterToSaveRestore - If set to a physical register, this 1595 /// specifies the register that llvm.savestack/llvm.restorestack should save 1596 /// and restore. 1597 unsigned StackPointerRegisterToSaveRestore; 1598 1599 /// ExceptionPointerRegister - If set to a physical register, this specifies 1600 /// the register that receives the exception address on entry to a landing 1601 /// pad. 1602 unsigned ExceptionPointerRegister; 1603 1604 /// ExceptionSelectorRegister - If set to a physical register, this specifies 1605 /// the register that receives the exception typeid on entry to a landing 1606 /// pad. 1607 unsigned ExceptionSelectorRegister; 1608 1609 /// RegClassForVT - This indicates the default register class to use for 1610 /// each ValueType the target supports natively. 1611 TargetRegisterClass *RegClassForVT[MVT::LAST_VALUETYPE]; 1612 unsigned char NumRegistersForVT[MVT::LAST_VALUETYPE]; 1613 EVT RegisterTypeForVT[MVT::LAST_VALUETYPE]; 1614 1615 /// TransformToType - For any value types we are promoting or expanding, this 1616 /// contains the value type that we are changing to. For Expanded types, this 1617 /// contains one step of the expand (e.g. i64 -> i32), even if there are 1618 /// multiple steps required (e.g. i64 -> i16). For types natively supported 1619 /// by the system, this holds the same type (e.g. i32 -> i32). 1620 EVT TransformToType[MVT::LAST_VALUETYPE]; 1621 1622 /// OpActions - For each operation and each value type, keep a LegalizeAction 1623 /// that indicates how instruction selection should deal with the operation. 1624 /// Most operations are Legal (aka, supported natively by the target), but 1625 /// operations that are not should be described. Note that operations on 1626 /// non-legal value types are not described here. 1627 /// This array is accessed using VT.getSimpleVT(), so it is subject to 1628 /// the MVT::MAX_ALLOWED_VALUETYPE * 2 bits. 1629 uint64_t OpActions[MVT::MAX_ALLOWED_VALUETYPE/(sizeof(uint64_t)*4)][ISD::BUILTIN_OP_END]; 1630 1631 /// LoadExtActions - For each load of load extension type and each value type, 1632 /// keep a LegalizeAction that indicates how instruction selection should deal 1633 /// with the load. 1634 uint64_t LoadExtActions[ISD::LAST_LOADEXT_TYPE]; 1635 1636 /// TruncStoreActions - For each truncating store, keep a LegalizeAction that 1637 /// indicates how instruction selection should deal with the store. 1638 uint64_t TruncStoreActions[MVT::LAST_VALUETYPE]; 1639 1640 /// IndexedModeActions - For each indexed mode and each value type, 1641 /// keep a pair of LegalizeAction that indicates how instruction 1642 /// selection should deal with the load / store. The first 1643 /// dimension is now the value_type for the reference. The second 1644 /// dimension is the load [0] vs. store[1]. The third dimension 1645 /// represents the various modes for load store. 1646 uint8_t IndexedModeActions[MVT::LAST_VALUETYPE][2][ISD::LAST_INDEXED_MODE]; 1647 1648 /// CondCodeActions - For each condition code (ISD::CondCode) keep a 1649 /// LegalizeAction that indicates how instruction selection should 1650 /// deal with the condition code. 1651 uint64_t CondCodeActions[ISD::SETCC_INVALID]; 1652 1653 ValueTypeActionImpl ValueTypeActions; 1654 1655 std::vector<std::pair<EVT, TargetRegisterClass*> > AvailableRegClasses; 1656 1657 /// TargetDAGCombineArray - Targets can specify ISD nodes that they would 1658 /// like PerformDAGCombine callbacks for by calling setTargetDAGCombine(), 1659 /// which sets a bit in this array. 1660 unsigned char 1661 TargetDAGCombineArray[(ISD::BUILTIN_OP_END+CHAR_BIT-1)/CHAR_BIT]; 1662 1663 /// PromoteToType - For operations that must be promoted to a specific type, 1664 /// this holds the destination type. This map should be sparse, so don't hold 1665 /// it as an array. 1666 /// 1667 /// Targets add entries to this map with AddPromotedToType(..), clients access 1668 /// this with getTypeToPromoteTo(..). 1669 std::map<std::pair<unsigned, MVT::SimpleValueType>, MVT::SimpleValueType> 1670 PromoteToType; 1671 1672 /// LibcallRoutineNames - Stores the name each libcall. 1673 /// 1674 const char *LibcallRoutineNames[RTLIB::UNKNOWN_LIBCALL]; 1675 1676 /// CmpLibcallCCs - The ISD::CondCode that should be used to test the result 1677 /// of each of the comparison libcall against zero. 1678 ISD::CondCode CmpLibcallCCs[RTLIB::UNKNOWN_LIBCALL]; 1679 1680 /// LibcallCallingConvs - Stores the CallingConv that should be used for each 1681 /// libcall. 1682 CallingConv::ID LibcallCallingConvs[RTLIB::UNKNOWN_LIBCALL]; 1683 1684protected: 1685 /// When lowering \@llvm.memset this field specifies the maximum number of 1686 /// store operations that may be substituted for the call to memset. Targets 1687 /// must set this value based on the cost threshold for that target. Targets 1688 /// should assume that the memset will be done using as many of the largest 1689 /// store operations first, followed by smaller ones, if necessary, per 1690 /// alignment restrictions. For example, storing 9 bytes on a 32-bit machine 1691 /// with 16-bit alignment would result in four 2-byte stores and one 1-byte 1692 /// store. This only applies to setting a constant array of a constant size. 1693 /// @brief Specify maximum number of store instructions per memset call. 1694 unsigned maxStoresPerMemset; 1695 1696 /// When lowering \@llvm.memcpy this field specifies the maximum number of 1697 /// store operations that may be substituted for a call to memcpy. Targets 1698 /// must set this value based on the cost threshold for that target. Targets 1699 /// should assume that the memcpy will be done using as many of the largest 1700 /// store operations first, followed by smaller ones, if necessary, per 1701 /// alignment restrictions. For example, storing 7 bytes on a 32-bit machine 1702 /// with 32-bit alignment would result in one 4-byte store, a one 2-byte store 1703 /// and one 1-byte store. This only applies to copying a constant array of 1704 /// constant size. 1705 /// @brief Specify maximum bytes of store instructions per memcpy call. 1706 unsigned maxStoresPerMemcpy; 1707 1708 /// When lowering \@llvm.memmove this field specifies the maximum number of 1709 /// store instructions that may be substituted for a call to memmove. Targets 1710 /// must set this value based on the cost threshold for that target. Targets 1711 /// should assume that the memmove will be done using as many of the largest 1712 /// store operations first, followed by smaller ones, if necessary, per 1713 /// alignment restrictions. For example, moving 9 bytes on a 32-bit machine 1714 /// with 8-bit alignment would result in nine 1-byte stores. This only 1715 /// applies to copying a constant array of constant size. 1716 /// @brief Specify maximum bytes of store instructions per memmove call. 1717 unsigned maxStoresPerMemmove; 1718 1719 /// This field specifies whether the target can benefit from code placement 1720 /// optimization. 1721 bool benefitFromCodePlacementOpt; 1722}; 1723} // end llvm namespace 1724 1725#endif 1726