InstCombineCalls.cpp revision 55fb9b0fcf89501a0abe74808f4e08e0b3a17207
1//===- InstCombineCalls.cpp -----------------------------------------------===// 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 visitCall and visitInvoke functions. 11// 12//===----------------------------------------------------------------------===// 13 14#include "InstCombine.h" 15#include "llvm/IntrinsicInst.h" 16#include "llvm/Support/CallSite.h" 17#include "llvm/Target/TargetData.h" 18#include "llvm/Analysis/MemoryBuiltins.h" 19#include "llvm/Transforms/Utils/BuildLibCalls.h" 20using namespace llvm; 21 22/// getPromotedType - Return the specified type promoted as it would be to pass 23/// though a va_arg area. 24static const Type *getPromotedType(const Type *Ty) { 25 if (const IntegerType* ITy = dyn_cast<IntegerType>(Ty)) { 26 if (ITy->getBitWidth() < 32) 27 return Type::getInt32Ty(Ty->getContext()); 28 } 29 return Ty; 30} 31 32/// EnforceKnownAlignment - If the specified pointer points to an object that 33/// we control, modify the object's alignment to PrefAlign. This isn't 34/// often possible though. If alignment is important, a more reliable approach 35/// is to simply align all global variables and allocation instructions to 36/// their preferred alignment from the beginning. 37/// 38static unsigned EnforceKnownAlignment(Value *V, 39 unsigned Align, unsigned PrefAlign) { 40 41 User *U = dyn_cast<User>(V); 42 if (!U) return Align; 43 44 switch (Operator::getOpcode(U)) { 45 default: break; 46 case Instruction::BitCast: 47 return EnforceKnownAlignment(U->getOperand(0), Align, PrefAlign); 48 case Instruction::GetElementPtr: { 49 // If all indexes are zero, it is just the alignment of the base pointer. 50 bool AllZeroOperands = true; 51 for (User::op_iterator i = U->op_begin() + 1, e = U->op_end(); i != e; ++i) 52 if (!isa<Constant>(*i) || 53 !cast<Constant>(*i)->isNullValue()) { 54 AllZeroOperands = false; 55 break; 56 } 57 58 if (AllZeroOperands) { 59 // Treat this like a bitcast. 60 return EnforceKnownAlignment(U->getOperand(0), Align, PrefAlign); 61 } 62 return Align; 63 } 64 case Instruction::Alloca: { 65 AllocaInst *AI = cast<AllocaInst>(V); 66 // If there is a requested alignment and if this is an alloca, round up. 67 if (AI->getAlignment() >= PrefAlign) 68 return AI->getAlignment(); 69 AI->setAlignment(PrefAlign); 70 return PrefAlign; 71 } 72 } 73 74 if (GlobalValue *GV = dyn_cast<GlobalValue>(V)) { 75 // If there is a large requested alignment and we can, bump up the alignment 76 // of the global. 77 if (GV->isDeclaration()) return Align; 78 79 if (GV->getAlignment() >= PrefAlign) 80 return GV->getAlignment(); 81 // We can only increase the alignment of the global if it has no alignment 82 // specified or if it is not assigned a section. If it is assigned a 83 // section, the global could be densely packed with other objects in the 84 // section, increasing the alignment could cause padding issues. 85 if (!GV->hasSection() || GV->getAlignment() == 0) 86 GV->setAlignment(PrefAlign); 87 return GV->getAlignment(); 88 } 89 90 return Align; 91} 92 93/// GetOrEnforceKnownAlignment - If the specified pointer has an alignment that 94/// we can determine, return it, otherwise return 0. If PrefAlign is specified, 95/// and it is more than the alignment of the ultimate object, see if we can 96/// increase the alignment of the ultimate object, making this check succeed. 97unsigned InstCombiner::GetOrEnforceKnownAlignment(Value *V, 98 unsigned PrefAlign) { 99 assert(V->getType()->isPointerTy() && 100 "GetOrEnforceKnownAlignment expects a pointer!"); 101 unsigned BitWidth = TD ? TD->getPointerSizeInBits() : 64; 102 APInt Mask = APInt::getAllOnesValue(BitWidth); 103 APInt KnownZero(BitWidth, 0), KnownOne(BitWidth, 0); 104 ComputeMaskedBits(V, Mask, KnownZero, KnownOne); 105 unsigned TrailZ = KnownZero.countTrailingOnes(); 106 107 // Avoid trouble with rediculously large TrailZ values, such as 108 // those computed from a null pointer. 109 TrailZ = std::min(TrailZ, unsigned(sizeof(unsigned) * CHAR_BIT - 1)); 110 111 unsigned Align = 1u << std::min(BitWidth - 1, TrailZ); 112 113 // LLVM doesn't support alignments larger than this currently. 114 Align = std::min(Align, +Value::MaximumAlignment); 115 116 if (PrefAlign > Align) 117 Align = EnforceKnownAlignment(V, Align, PrefAlign); 118 119 // We don't need to make any adjustment. 120 return Align; 121} 122 123Instruction *InstCombiner::SimplifyMemTransfer(MemIntrinsic *MI) { 124 unsigned DstAlign = GetOrEnforceKnownAlignment(MI->getArgOperand(0)); 125 unsigned SrcAlign = GetOrEnforceKnownAlignment(MI->getArgOperand(1)); 126 unsigned MinAlign = std::min(DstAlign, SrcAlign); 127 unsigned CopyAlign = MI->getAlignment(); 128 129 if (CopyAlign < MinAlign) { 130 MI->setAlignment(ConstantInt::get(MI->getAlignmentType(), 131 MinAlign, false)); 132 return MI; 133 } 134 135 // If MemCpyInst length is 1/2/4/8 bytes then replace memcpy with 136 // load/store. 137 ConstantInt *MemOpLength = dyn_cast<ConstantInt>(MI->getArgOperand(2)); 138 if (MemOpLength == 0) return 0; 139 140 // Source and destination pointer types are always "i8*" for intrinsic. See 141 // if the size is something we can handle with a single primitive load/store. 142 // A single load+store correctly handles overlapping memory in the memmove 143 // case. 144 unsigned Size = MemOpLength->getZExtValue(); 145 if (Size == 0) return MI; // Delete this mem transfer. 146 147 if (Size > 8 || (Size&(Size-1))) 148 return 0; // If not 1/2/4/8 bytes, exit. 149 150 // Use an integer load+store unless we can find something better. 151 unsigned SrcAddrSp = 152 cast<PointerType>(MI->getArgOperand(1)->getType())->getAddressSpace(); 153 unsigned DstAddrSp = 154 cast<PointerType>(MI->getArgOperand(0)->getType())->getAddressSpace(); 155 156 const IntegerType* IntType = IntegerType::get(MI->getContext(), Size<<3); 157 Type *NewSrcPtrTy = PointerType::get(IntType, SrcAddrSp); 158 Type *NewDstPtrTy = PointerType::get(IntType, DstAddrSp); 159 160 // Memcpy forces the use of i8* for the source and destination. That means 161 // that if you're using memcpy to move one double around, you'll get a cast 162 // from double* to i8*. We'd much rather use a double load+store rather than 163 // an i64 load+store, here because this improves the odds that the source or 164 // dest address will be promotable. See if we can find a better type than the 165 // integer datatype. 166 Value *StrippedDest = MI->getArgOperand(0)->stripPointerCasts(); 167 if (StrippedDest != MI->getArgOperand(0)) { 168 const Type *SrcETy = cast<PointerType>(StrippedDest->getType()) 169 ->getElementType(); 170 if (TD && SrcETy->isSized() && TD->getTypeStoreSize(SrcETy) == Size) { 171 // The SrcETy might be something like {{{double}}} or [1 x double]. Rip 172 // down through these levels if so. 173 while (!SrcETy->isSingleValueType()) { 174 if (const StructType *STy = dyn_cast<StructType>(SrcETy)) { 175 if (STy->getNumElements() == 1) 176 SrcETy = STy->getElementType(0); 177 else 178 break; 179 } else if (const ArrayType *ATy = dyn_cast<ArrayType>(SrcETy)) { 180 if (ATy->getNumElements() == 1) 181 SrcETy = ATy->getElementType(); 182 else 183 break; 184 } else 185 break; 186 } 187 188 if (SrcETy->isSingleValueType()) { 189 NewSrcPtrTy = PointerType::get(SrcETy, SrcAddrSp); 190 NewDstPtrTy = PointerType::get(SrcETy, DstAddrSp); 191 } 192 } 193 } 194 195 196 // If the memcpy/memmove provides better alignment info than we can 197 // infer, use it. 198 SrcAlign = std::max(SrcAlign, CopyAlign); 199 DstAlign = std::max(DstAlign, CopyAlign); 200 201 Value *Src = Builder->CreateBitCast(MI->getArgOperand(1), NewSrcPtrTy); 202 Value *Dest = Builder->CreateBitCast(MI->getArgOperand(0), NewDstPtrTy); 203 Instruction *L = new LoadInst(Src, "tmp", MI->isVolatile(), SrcAlign); 204 InsertNewInstBefore(L, *MI); 205 InsertNewInstBefore(new StoreInst(L, Dest, MI->isVolatile(), DstAlign), 206 *MI); 207 208 // Set the size of the copy to 0, it will be deleted on the next iteration. 209 MI->setArgOperand(2, Constant::getNullValue(MemOpLength->getType())); 210 return MI; 211} 212 213Instruction *InstCombiner::SimplifyMemSet(MemSetInst *MI) { 214 unsigned Alignment = GetOrEnforceKnownAlignment(MI->getDest()); 215 if (MI->getAlignment() < Alignment) { 216 MI->setAlignment(ConstantInt::get(MI->getAlignmentType(), 217 Alignment, false)); 218 return MI; 219 } 220 221 // Extract the length and alignment and fill if they are constant. 222 ConstantInt *LenC = dyn_cast<ConstantInt>(MI->getLength()); 223 ConstantInt *FillC = dyn_cast<ConstantInt>(MI->getValue()); 224 if (!LenC || !FillC || !FillC->getType()->isIntegerTy(8)) 225 return 0; 226 uint64_t Len = LenC->getZExtValue(); 227 Alignment = MI->getAlignment(); 228 229 // If the length is zero, this is a no-op 230 if (Len == 0) return MI; // memset(d,c,0,a) -> noop 231 232 // memset(s,c,n) -> store s, c (for n=1,2,4,8) 233 if (Len <= 8 && isPowerOf2_32((uint32_t)Len)) { 234 const Type *ITy = IntegerType::get(MI->getContext(), Len*8); // n=1 -> i8. 235 236 Value *Dest = MI->getDest(); 237 unsigned DstAddrSp = cast<PointerType>(Dest->getType())->getAddressSpace(); 238 Type *NewDstPtrTy = PointerType::get(ITy, DstAddrSp); 239 Dest = Builder->CreateBitCast(Dest, NewDstPtrTy); 240 241 // Alignment 0 is identity for alignment 1 for memset, but not store. 242 if (Alignment == 0) Alignment = 1; 243 244 // Extract the fill value and store. 245 uint64_t Fill = FillC->getZExtValue()*0x0101010101010101ULL; 246 InsertNewInstBefore(new StoreInst(ConstantInt::get(ITy, Fill), 247 Dest, false, Alignment), *MI); 248 249 // Set the size of the copy to 0, it will be deleted on the next iteration. 250 MI->setLength(Constant::getNullValue(LenC->getType())); 251 return MI; 252 } 253 254 return 0; 255} 256 257/// visitCallInst - CallInst simplification. This mostly only handles folding 258/// of intrinsic instructions. For normal calls, it allows visitCallSite to do 259/// the heavy lifting. 260/// 261Instruction *InstCombiner::visitCallInst(CallInst &CI) { 262 if (isFreeCall(&CI)) 263 return visitFree(CI); 264 if (isMalloc(&CI)) 265 return visitMalloc(CI); 266 267 // If the caller function is nounwind, mark the call as nounwind, even if the 268 // callee isn't. 269 if (CI.getParent()->getParent()->doesNotThrow() && 270 !CI.doesNotThrow()) { 271 CI.setDoesNotThrow(); 272 return &CI; 273 } 274 275 IntrinsicInst *II = dyn_cast<IntrinsicInst>(&CI); 276 if (!II) return visitCallSite(&CI); 277 278 // Intrinsics cannot occur in an invoke, so handle them here instead of in 279 // visitCallSite. 280 if (MemIntrinsic *MI = dyn_cast<MemIntrinsic>(II)) { 281 bool Changed = false; 282 283 // memmove/cpy/set of zero bytes is a noop. 284 if (Constant *NumBytes = dyn_cast<Constant>(MI->getLength())) { 285 if (NumBytes->isNullValue()) 286 return EraseInstFromFunction(CI); 287 288 if (ConstantInt *CI = dyn_cast<ConstantInt>(NumBytes)) 289 if (CI->getZExtValue() == 1) { 290 // Replace the instruction with just byte operations. We would 291 // transform other cases to loads/stores, but we don't know if 292 // alignment is sufficient. 293 } 294 } 295 296 // No other transformations apply to volatile transfers. 297 if (MI->isVolatile()) 298 return 0; 299 300 // If we have a memmove and the source operation is a constant global, 301 // then the source and dest pointers can't alias, so we can change this 302 // into a call to memcpy. 303 if (MemMoveInst *MMI = dyn_cast<MemMoveInst>(MI)) { 304 if (GlobalVariable *GVSrc = dyn_cast<GlobalVariable>(MMI->getSource())) 305 if (GVSrc->isConstant()) { 306 Module *M = CI.getParent()->getParent()->getParent(); 307 Intrinsic::ID MemCpyID = Intrinsic::memcpy; 308 const Type *Tys[3] = { CI.getArgOperand(0)->getType(), 309 CI.getArgOperand(1)->getType(), 310 CI.getArgOperand(2)->getType() }; 311 CI.setCalledFunction(Intrinsic::getDeclaration(M, MemCpyID, Tys, 3)); 312 Changed = true; 313 } 314 } 315 316 if (MemTransferInst *MTI = dyn_cast<MemTransferInst>(MI)) { 317 // memmove(x,x,size) -> noop. 318 if (MTI->getSource() == MTI->getDest()) 319 return EraseInstFromFunction(CI); 320 } 321 322 // If we can determine a pointer alignment that is bigger than currently 323 // set, update the alignment. 324 if (isa<MemTransferInst>(MI)) { 325 if (Instruction *I = SimplifyMemTransfer(MI)) 326 return I; 327 } else if (MemSetInst *MSI = dyn_cast<MemSetInst>(MI)) { 328 if (Instruction *I = SimplifyMemSet(MSI)) 329 return I; 330 } 331 332 if (Changed) return II; 333 } 334 335 switch (II->getIntrinsicID()) { 336 default: break; 337 case Intrinsic::objectsize: { 338 // We need target data for just about everything so depend on it. 339 if (!TD) break; 340 341 const Type *ReturnTy = CI.getType(); 342 bool Min = (cast<ConstantInt>(II->getArgOperand(1))->getZExtValue() == 1); 343 344 // Get to the real allocated thing and offset as fast as possible. 345 Value *Op1 = II->getArgOperand(0)->stripPointerCasts(); 346 347 // If we've stripped down to a single global variable that we 348 // can know the size of then just return that. 349 if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Op1)) { 350 if (GV->hasDefinitiveInitializer()) { 351 Constant *C = GV->getInitializer(); 352 uint64_t GlobalSize = TD->getTypeAllocSize(C->getType()); 353 return ReplaceInstUsesWith(CI, ConstantInt::get(ReturnTy, GlobalSize)); 354 } else { 355 // Can't determine size of the GV. 356 Constant *RetVal = ConstantInt::get(ReturnTy, Min ? 0 : -1ULL); 357 return ReplaceInstUsesWith(CI, RetVal); 358 } 359 } else if (AllocaInst *AI = dyn_cast<AllocaInst>(Op1)) { 360 // Get alloca size. 361 if (AI->getAllocatedType()->isSized()) { 362 uint64_t AllocaSize = TD->getTypeAllocSize(AI->getAllocatedType()); 363 if (AI->isArrayAllocation()) { 364 const ConstantInt *C = dyn_cast<ConstantInt>(AI->getArraySize()); 365 if (!C) break; 366 AllocaSize *= C->getZExtValue(); 367 } 368 return ReplaceInstUsesWith(CI, ConstantInt::get(ReturnTy, AllocaSize)); 369 } 370 } else if (CallInst *MI = extractMallocCall(Op1)) { 371 const Type* MallocType = getMallocAllocatedType(MI); 372 // Get alloca size. 373 if (MallocType && MallocType->isSized()) { 374 if (Value *NElems = getMallocArraySize(MI, TD, true)) { 375 if (ConstantInt *NElements = dyn_cast<ConstantInt>(NElems)) 376 return ReplaceInstUsesWith(CI, ConstantInt::get(ReturnTy, 377 (NElements->getZExtValue() * TD->getTypeAllocSize(MallocType)))); 378 } 379 } 380 } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Op1)) { 381 // Only handle constant GEPs here. 382 if (CE->getOpcode() != Instruction::GetElementPtr) break; 383 GEPOperator *GEP = cast<GEPOperator>(CE); 384 385 // Make sure we're not a constant offset from an external 386 // global. 387 Value *Operand = GEP->getPointerOperand(); 388 Operand = Operand->stripPointerCasts(); 389 if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Operand)) 390 if (!GV->hasDefinitiveInitializer()) break; 391 392 // Get what we're pointing to and its size. 393 const PointerType *BaseType = 394 cast<PointerType>(Operand->getType()); 395 uint64_t Size = TD->getTypeAllocSize(BaseType->getElementType()); 396 397 // Get the current byte offset into the thing. Use the original 398 // operand in case we're looking through a bitcast. 399 SmallVector<Value*, 8> Ops(CE->op_begin()+1, CE->op_end()); 400 const PointerType *OffsetType = 401 cast<PointerType>(GEP->getPointerOperand()->getType()); 402 uint64_t Offset = TD->getIndexedOffset(OffsetType, &Ops[0], Ops.size()); 403 404 if (Size < Offset) { 405 // Out of bound reference? Negative index normalized to large 406 // index? Just return "I don't know". 407 Constant *RetVal = ConstantInt::get(ReturnTy, Min ? 0 : -1ULL); 408 return ReplaceInstUsesWith(CI, RetVal); 409 } 410 411 Constant *RetVal = ConstantInt::get(ReturnTy, Size-Offset); 412 return ReplaceInstUsesWith(CI, RetVal); 413 } 414 415 // Do not return "I don't know" here. Later optimization passes could 416 // make it possible to evaluate objectsize to a constant. 417 break; 418 } 419 case Intrinsic::bswap: 420 // bswap(bswap(x)) -> x 421 if (IntrinsicInst *Operand = dyn_cast<IntrinsicInst>(II->getArgOperand(0))) 422 if (Operand->getIntrinsicID() == Intrinsic::bswap) 423 return ReplaceInstUsesWith(CI, Operand->getArgOperand(0)); 424 425 // bswap(trunc(bswap(x))) -> trunc(lshr(x, c)) 426 if (TruncInst *TI = dyn_cast<TruncInst>(II->getArgOperand(0))) { 427 if (IntrinsicInst *Operand = dyn_cast<IntrinsicInst>(TI->getOperand(0))) 428 if (Operand->getIntrinsicID() == Intrinsic::bswap) { 429 unsigned C = Operand->getType()->getPrimitiveSizeInBits() - 430 TI->getType()->getPrimitiveSizeInBits(); 431 Value *CV = ConstantInt::get(Operand->getType(), C); 432 Value *V = Builder->CreateLShr(Operand->getArgOperand(0), CV); 433 return new TruncInst(V, TI->getType()); 434 } 435 } 436 437 break; 438 case Intrinsic::powi: 439 if (ConstantInt *Power = dyn_cast<ConstantInt>(II->getArgOperand(1))) { 440 // powi(x, 0) -> 1.0 441 if (Power->isZero()) 442 return ReplaceInstUsesWith(CI, ConstantFP::get(CI.getType(), 1.0)); 443 // powi(x, 1) -> x 444 if (Power->isOne()) 445 return ReplaceInstUsesWith(CI, II->getArgOperand(0)); 446 // powi(x, -1) -> 1/x 447 if (Power->isAllOnesValue()) 448 return BinaryOperator::CreateFDiv(ConstantFP::get(CI.getType(), 1.0), 449 II->getArgOperand(0)); 450 } 451 break; 452 case Intrinsic::cttz: { 453 // If all bits below the first known one are known zero, 454 // this value is constant. 455 const IntegerType *IT = cast<IntegerType>(II->getArgOperand(0)->getType()); 456 uint32_t BitWidth = IT->getBitWidth(); 457 APInt KnownZero(BitWidth, 0); 458 APInt KnownOne(BitWidth, 0); 459 ComputeMaskedBits(II->getArgOperand(0), APInt::getAllOnesValue(BitWidth), 460 KnownZero, KnownOne); 461 unsigned TrailingZeros = KnownOne.countTrailingZeros(); 462 APInt Mask(APInt::getLowBitsSet(BitWidth, TrailingZeros)); 463 if ((Mask & KnownZero) == Mask) 464 return ReplaceInstUsesWith(CI, ConstantInt::get(IT, 465 APInt(BitWidth, TrailingZeros))); 466 467 } 468 break; 469 case Intrinsic::ctlz: { 470 // If all bits above the first known one are known zero, 471 // this value is constant. 472 const IntegerType *IT = cast<IntegerType>(II->getArgOperand(0)->getType()); 473 uint32_t BitWidth = IT->getBitWidth(); 474 APInt KnownZero(BitWidth, 0); 475 APInt KnownOne(BitWidth, 0); 476 ComputeMaskedBits(II->getArgOperand(0), APInt::getAllOnesValue(BitWidth), 477 KnownZero, KnownOne); 478 unsigned LeadingZeros = KnownOne.countLeadingZeros(); 479 APInt Mask(APInt::getHighBitsSet(BitWidth, LeadingZeros)); 480 if ((Mask & KnownZero) == Mask) 481 return ReplaceInstUsesWith(CI, ConstantInt::get(IT, 482 APInt(BitWidth, LeadingZeros))); 483 484 } 485 break; 486 case Intrinsic::uadd_with_overflow: { 487 Value *LHS = II->getArgOperand(0), *RHS = II->getArgOperand(1); 488 const IntegerType *IT = cast<IntegerType>(II->getArgOperand(0)->getType()); 489 uint32_t BitWidth = IT->getBitWidth(); 490 APInt Mask = APInt::getSignBit(BitWidth); 491 APInt LHSKnownZero(BitWidth, 0); 492 APInt LHSKnownOne(BitWidth, 0); 493 ComputeMaskedBits(LHS, Mask, LHSKnownZero, LHSKnownOne); 494 bool LHSKnownNegative = LHSKnownOne[BitWidth - 1]; 495 bool LHSKnownPositive = LHSKnownZero[BitWidth - 1]; 496 497 if (LHSKnownNegative || LHSKnownPositive) { 498 APInt RHSKnownZero(BitWidth, 0); 499 APInt RHSKnownOne(BitWidth, 0); 500 ComputeMaskedBits(RHS, Mask, RHSKnownZero, RHSKnownOne); 501 bool RHSKnownNegative = RHSKnownOne[BitWidth - 1]; 502 bool RHSKnownPositive = RHSKnownZero[BitWidth - 1]; 503 if (LHSKnownNegative && RHSKnownNegative) { 504 // The sign bit is set in both cases: this MUST overflow. 505 // Create a simple add instruction, and insert it into the struct. 506 Instruction *Add = BinaryOperator::CreateAdd(LHS, RHS, "", &CI); 507 Worklist.Add(Add); 508 Constant *V[] = { 509 UndefValue::get(LHS->getType()),ConstantInt::getTrue(II->getContext()) 510 }; 511 Constant *Struct = ConstantStruct::get(II->getContext(), V, 2, false); 512 return InsertValueInst::Create(Struct, Add, 0); 513 } 514 515 if (LHSKnownPositive && RHSKnownPositive) { 516 // The sign bit is clear in both cases: this CANNOT overflow. 517 // Create a simple add instruction, and insert it into the struct. 518 Instruction *Add = BinaryOperator::CreateNUWAdd(LHS, RHS, "", &CI); 519 Worklist.Add(Add); 520 Constant *V[] = { 521 UndefValue::get(LHS->getType()), 522 ConstantInt::getFalse(II->getContext()) 523 }; 524 Constant *Struct = ConstantStruct::get(II->getContext(), V, 2, false); 525 return InsertValueInst::Create(Struct, Add, 0); 526 } 527 } 528 } 529 // FALL THROUGH uadd into sadd 530 case Intrinsic::sadd_with_overflow: 531 // Canonicalize constants into the RHS. 532 if (isa<Constant>(II->getArgOperand(0)) && 533 !isa<Constant>(II->getArgOperand(1))) { 534 Value *LHS = II->getArgOperand(0); 535 II->setArgOperand(0, II->getArgOperand(1)); 536 II->setArgOperand(1, LHS); 537 return II; 538 } 539 540 // X + undef -> undef 541 if (isa<UndefValue>(II->getArgOperand(1))) 542 return ReplaceInstUsesWith(CI, UndefValue::get(II->getType())); 543 544 if (ConstantInt *RHS = dyn_cast<ConstantInt>(II->getArgOperand(1))) { 545 // X + 0 -> {X, false} 546 if (RHS->isZero()) { 547 Constant *V[] = { 548 UndefValue::get(II->getArgOperand(0)->getType()), 549 ConstantInt::getFalse(II->getContext()) 550 }; 551 Constant *Struct = ConstantStruct::get(II->getContext(), V, 2, false); 552 return InsertValueInst::Create(Struct, II->getArgOperand(0), 0); 553 } 554 } 555 break; 556 case Intrinsic::usub_with_overflow: 557 case Intrinsic::ssub_with_overflow: 558 // undef - X -> undef 559 // X - undef -> undef 560 if (isa<UndefValue>(II->getArgOperand(0)) || 561 isa<UndefValue>(II->getArgOperand(1))) 562 return ReplaceInstUsesWith(CI, UndefValue::get(II->getType())); 563 564 if (ConstantInt *RHS = dyn_cast<ConstantInt>(II->getArgOperand(1))) { 565 // X - 0 -> {X, false} 566 if (RHS->isZero()) { 567 Constant *V[] = { 568 UndefValue::get(II->getArgOperand(0)->getType()), 569 ConstantInt::getFalse(II->getContext()) 570 }; 571 Constant *Struct = ConstantStruct::get(II->getContext(), V, 2, false); 572 return InsertValueInst::Create(Struct, II->getArgOperand(0), 0); 573 } 574 } 575 break; 576 case Intrinsic::umul_with_overflow: 577 case Intrinsic::smul_with_overflow: 578 // Canonicalize constants into the RHS. 579 if (isa<Constant>(II->getArgOperand(0)) && 580 !isa<Constant>(II->getArgOperand(1))) { 581 Value *LHS = II->getArgOperand(0); 582 II->setArgOperand(0, II->getArgOperand(1)); 583 II->setArgOperand(1, LHS); 584 return II; 585 } 586 587 // X * undef -> undef 588 if (isa<UndefValue>(II->getArgOperand(1))) 589 return ReplaceInstUsesWith(CI, UndefValue::get(II->getType())); 590 591 if (ConstantInt *RHSI = dyn_cast<ConstantInt>(II->getArgOperand(1))) { 592 // X*0 -> {0, false} 593 if (RHSI->isZero()) 594 return ReplaceInstUsesWith(CI, Constant::getNullValue(II->getType())); 595 596 // X * 1 -> {X, false} 597 if (RHSI->equalsInt(1)) { 598 Constant *V[] = { 599 UndefValue::get(II->getArgOperand(0)->getType()), 600 ConstantInt::getFalse(II->getContext()) 601 }; 602 Constant *Struct = ConstantStruct::get(II->getContext(), V, 2, false); 603 return InsertValueInst::Create(Struct, II->getArgOperand(0), 0); 604 } 605 } 606 break; 607 case Intrinsic::ppc_altivec_lvx: 608 case Intrinsic::ppc_altivec_lvxl: 609 case Intrinsic::x86_sse_loadu_ps: 610 case Intrinsic::x86_sse2_loadu_pd: 611 case Intrinsic::x86_sse2_loadu_dq: 612 // Turn PPC lvx -> load if the pointer is known aligned. 613 // Turn X86 loadups -> load if the pointer is known aligned. 614 if (GetOrEnforceKnownAlignment(II->getArgOperand(0), 16) >= 16) { 615 Value *Ptr = Builder->CreateBitCast(II->getArgOperand(0), 616 PointerType::getUnqual(II->getType())); 617 return new LoadInst(Ptr); 618 } 619 break; 620 case Intrinsic::ppc_altivec_stvx: 621 case Intrinsic::ppc_altivec_stvxl: 622 // Turn stvx -> store if the pointer is known aligned. 623 if (GetOrEnforceKnownAlignment(II->getArgOperand(1), 16) >= 16) { 624 const Type *OpPtrTy = 625 PointerType::getUnqual(II->getArgOperand(0)->getType()); 626 Value *Ptr = Builder->CreateBitCast(II->getArgOperand(1), OpPtrTy); 627 return new StoreInst(II->getArgOperand(0), Ptr); 628 } 629 break; 630 case Intrinsic::x86_sse_storeu_ps: 631 case Intrinsic::x86_sse2_storeu_pd: 632 case Intrinsic::x86_sse2_storeu_dq: 633 // Turn X86 storeu -> store if the pointer is known aligned. 634 if (GetOrEnforceKnownAlignment(II->getArgOperand(0), 16) >= 16) { 635 const Type *OpPtrTy = 636 PointerType::getUnqual(II->getArgOperand(1)->getType()); 637 Value *Ptr = Builder->CreateBitCast(II->getArgOperand(0), OpPtrTy); 638 return new StoreInst(II->getArgOperand(1), Ptr); 639 } 640 break; 641 642 case Intrinsic::x86_sse_cvttss2si: { 643 // These intrinsics only demands the 0th element of its input vector. If 644 // we can simplify the input based on that, do so now. 645 unsigned VWidth = 646 cast<VectorType>(II->getArgOperand(0)->getType())->getNumElements(); 647 APInt DemandedElts(VWidth, 1); 648 APInt UndefElts(VWidth, 0); 649 if (Value *V = SimplifyDemandedVectorElts(II->getArgOperand(0), 650 DemandedElts, UndefElts)) { 651 II->setArgOperand(0, V); 652 return II; 653 } 654 break; 655 } 656 657 case Intrinsic::ppc_altivec_vperm: 658 // Turn vperm(V1,V2,mask) -> shuffle(V1,V2,mask) if mask is a constant. 659 if (ConstantVector *Mask = dyn_cast<ConstantVector>(II->getArgOperand(2))) { 660 assert(Mask->getNumOperands() == 16 && "Bad type for intrinsic!"); 661 662 // Check that all of the elements are integer constants or undefs. 663 bool AllEltsOk = true; 664 for (unsigned i = 0; i != 16; ++i) { 665 if (!isa<ConstantInt>(Mask->getOperand(i)) && 666 !isa<UndefValue>(Mask->getOperand(i))) { 667 AllEltsOk = false; 668 break; 669 } 670 } 671 672 if (AllEltsOk) { 673 // Cast the input vectors to byte vectors. 674 Value *Op0 = Builder->CreateBitCast(II->getArgOperand(0), 675 Mask->getType()); 676 Value *Op1 = Builder->CreateBitCast(II->getArgOperand(1), 677 Mask->getType()); 678 Value *Result = UndefValue::get(Op0->getType()); 679 680 // Only extract each element once. 681 Value *ExtractedElts[32]; 682 memset(ExtractedElts, 0, sizeof(ExtractedElts)); 683 684 for (unsigned i = 0; i != 16; ++i) { 685 if (isa<UndefValue>(Mask->getOperand(i))) 686 continue; 687 unsigned Idx=cast<ConstantInt>(Mask->getOperand(i))->getZExtValue(); 688 Idx &= 31; // Match the hardware behavior. 689 690 if (ExtractedElts[Idx] == 0) { 691 ExtractedElts[Idx] = 692 Builder->CreateExtractElement(Idx < 16 ? Op0 : Op1, 693 ConstantInt::get(Type::getInt32Ty(II->getContext()), 694 Idx&15, false), "tmp"); 695 } 696 697 // Insert this value into the result vector. 698 Result = Builder->CreateInsertElement(Result, ExtractedElts[Idx], 699 ConstantInt::get(Type::getInt32Ty(II->getContext()), 700 i, false), "tmp"); 701 } 702 return CastInst::Create(Instruction::BitCast, Result, CI.getType()); 703 } 704 } 705 break; 706 707 case Intrinsic::arm_neon_vld1: 708 case Intrinsic::arm_neon_vld2: 709 case Intrinsic::arm_neon_vld3: 710 case Intrinsic::arm_neon_vld4: 711 case Intrinsic::arm_neon_vld2lane: 712 case Intrinsic::arm_neon_vld3lane: 713 case Intrinsic::arm_neon_vld4lane: 714 case Intrinsic::arm_neon_vst1: 715 case Intrinsic::arm_neon_vst2: 716 case Intrinsic::arm_neon_vst3: 717 case Intrinsic::arm_neon_vst4: 718 case Intrinsic::arm_neon_vst2lane: 719 case Intrinsic::arm_neon_vst3lane: 720 case Intrinsic::arm_neon_vst4lane: { 721 unsigned MemAlign = GetOrEnforceKnownAlignment(II->getArgOperand(0)); 722 unsigned AlignArg = II->getNumArgOperands() - 1; 723 ConstantInt *IntrAlign = dyn_cast<ConstantInt>(II->getArgOperand(AlignArg)); 724 if (IntrAlign && IntrAlign->getZExtValue() < MemAlign) { 725 II->setArgOperand(AlignArg, 726 ConstantInt::get(Type::getInt32Ty(II->getContext()), 727 MemAlign, false)); 728 return II; 729 } 730 break; 731 } 732 733 case Intrinsic::stackrestore: { 734 // If the save is right next to the restore, remove the restore. This can 735 // happen when variable allocas are DCE'd. 736 if (IntrinsicInst *SS = dyn_cast<IntrinsicInst>(II->getArgOperand(0))) { 737 if (SS->getIntrinsicID() == Intrinsic::stacksave) { 738 BasicBlock::iterator BI = SS; 739 if (&*++BI == II) 740 return EraseInstFromFunction(CI); 741 } 742 } 743 744 // Scan down this block to see if there is another stack restore in the 745 // same block without an intervening call/alloca. 746 BasicBlock::iterator BI = II; 747 TerminatorInst *TI = II->getParent()->getTerminator(); 748 bool CannotRemove = false; 749 for (++BI; &*BI != TI; ++BI) { 750 if (isa<AllocaInst>(BI) || isMalloc(BI)) { 751 CannotRemove = true; 752 break; 753 } 754 if (CallInst *BCI = dyn_cast<CallInst>(BI)) { 755 if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(BCI)) { 756 // If there is a stackrestore below this one, remove this one. 757 if (II->getIntrinsicID() == Intrinsic::stackrestore) 758 return EraseInstFromFunction(CI); 759 // Otherwise, ignore the intrinsic. 760 } else { 761 // If we found a non-intrinsic call, we can't remove the stack 762 // restore. 763 CannotRemove = true; 764 break; 765 } 766 } 767 } 768 769 // If the stack restore is in a return/unwind block and if there are no 770 // allocas or calls between the restore and the return, nuke the restore. 771 if (!CannotRemove && (isa<ReturnInst>(TI) || isa<UnwindInst>(TI))) 772 return EraseInstFromFunction(CI); 773 break; 774 } 775 } 776 777 return visitCallSite(II); 778} 779 780// InvokeInst simplification 781// 782Instruction *InstCombiner::visitInvokeInst(InvokeInst &II) { 783 return visitCallSite(&II); 784} 785 786/// isSafeToEliminateVarargsCast - If this cast does not affect the value 787/// passed through the varargs area, we can eliminate the use of the cast. 788static bool isSafeToEliminateVarargsCast(const CallSite CS, 789 const CastInst * const CI, 790 const TargetData * const TD, 791 const int ix) { 792 if (!CI->isLosslessCast()) 793 return false; 794 795 // The size of ByVal arguments is derived from the type, so we 796 // can't change to a type with a different size. If the size were 797 // passed explicitly we could avoid this check. 798 if (!CS.paramHasAttr(ix, Attribute::ByVal)) 799 return true; 800 801 const Type* SrcTy = 802 cast<PointerType>(CI->getOperand(0)->getType())->getElementType(); 803 const Type* DstTy = cast<PointerType>(CI->getType())->getElementType(); 804 if (!SrcTy->isSized() || !DstTy->isSized()) 805 return false; 806 if (!TD || TD->getTypeAllocSize(SrcTy) != TD->getTypeAllocSize(DstTy)) 807 return false; 808 return true; 809} 810 811namespace { 812class InstCombineFortifiedLibCalls : public SimplifyFortifiedLibCalls { 813 InstCombiner *IC; 814protected: 815 void replaceCall(Value *With) { 816 NewInstruction = IC->ReplaceInstUsesWith(*CI, With); 817 } 818 bool isFoldable(unsigned SizeCIOp, unsigned SizeArgOp, bool isString) const { 819 if (ConstantInt *SizeCI = 820 dyn_cast<ConstantInt>(CI->getArgOperand(SizeCIOp))) { 821 if (SizeCI->isAllOnesValue()) 822 return true; 823 if (isString) 824 return SizeCI->getZExtValue() >= 825 GetStringLength(CI->getArgOperand(SizeArgOp)); 826 if (ConstantInt *Arg = dyn_cast<ConstantInt>( 827 CI->getArgOperand(SizeArgOp))) 828 return SizeCI->getZExtValue() >= Arg->getZExtValue(); 829 } 830 return false; 831 } 832public: 833 InstCombineFortifiedLibCalls(InstCombiner *IC) : IC(IC), NewInstruction(0) { } 834 Instruction *NewInstruction; 835}; 836} // end anonymous namespace 837 838// Try to fold some different type of calls here. 839// Currently we're only working with the checking functions, memcpy_chk, 840// mempcpy_chk, memmove_chk, memset_chk, strcpy_chk, stpcpy_chk, strncpy_chk, 841// strcat_chk and strncat_chk. 842Instruction *InstCombiner::tryOptimizeCall(CallInst *CI, const TargetData *TD) { 843 if (CI->getCalledFunction() == 0) return 0; 844 845 InstCombineFortifiedLibCalls Simplifier(this); 846 Simplifier.fold(CI, TD); 847 return Simplifier.NewInstruction; 848} 849 850// visitCallSite - Improvements for call and invoke instructions. 851// 852Instruction *InstCombiner::visitCallSite(CallSite CS) { 853 bool Changed = false; 854 855 // If the callee is a constexpr cast of a function, attempt to move the cast 856 // to the arguments of the call/invoke. 857 if (transformConstExprCastCall(CS)) return 0; 858 859 Value *Callee = CS.getCalledValue(); 860 861 if (Function *CalleeF = dyn_cast<Function>(Callee)) 862 // If the call and callee calling conventions don't match, this call must 863 // be unreachable, as the call is undefined. 864 if (CalleeF->getCallingConv() != CS.getCallingConv() && 865 // Only do this for calls to a function with a body. A prototype may 866 // not actually end up matching the implementation's calling conv for a 867 // variety of reasons (e.g. it may be written in assembly). 868 !CalleeF->isDeclaration()) { 869 Instruction *OldCall = CS.getInstruction(); 870 new StoreInst(ConstantInt::getTrue(Callee->getContext()), 871 UndefValue::get(Type::getInt1PtrTy(Callee->getContext())), 872 OldCall); 873 // If OldCall dues not return void then replaceAllUsesWith undef. 874 // This allows ValueHandlers and custom metadata to adjust itself. 875 if (!OldCall->getType()->isVoidTy()) 876 OldCall->replaceAllUsesWith(UndefValue::get(OldCall->getType())); 877 if (isa<CallInst>(OldCall)) 878 return EraseInstFromFunction(*OldCall); 879 880 // We cannot remove an invoke, because it would change the CFG, just 881 // change the callee to a null pointer. 882 cast<InvokeInst>(OldCall)->setCalledFunction( 883 Constant::getNullValue(CalleeF->getType())); 884 return 0; 885 } 886 887 if (isa<ConstantPointerNull>(Callee) || isa<UndefValue>(Callee)) { 888 // This instruction is not reachable, just remove it. We insert a store to 889 // undef so that we know that this code is not reachable, despite the fact 890 // that we can't modify the CFG here. 891 new StoreInst(ConstantInt::getTrue(Callee->getContext()), 892 UndefValue::get(Type::getInt1PtrTy(Callee->getContext())), 893 CS.getInstruction()); 894 895 // If CS does not return void then replaceAllUsesWith undef. 896 // This allows ValueHandlers and custom metadata to adjust itself. 897 if (!CS.getInstruction()->getType()->isVoidTy()) 898 CS.getInstruction()-> 899 replaceAllUsesWith(UndefValue::get(CS.getInstruction()->getType())); 900 901 if (InvokeInst *II = dyn_cast<InvokeInst>(CS.getInstruction())) { 902 // Don't break the CFG, insert a dummy cond branch. 903 BranchInst::Create(II->getNormalDest(), II->getUnwindDest(), 904 ConstantInt::getTrue(Callee->getContext()), II); 905 } 906 return EraseInstFromFunction(*CS.getInstruction()); 907 } 908 909 if (BitCastInst *BC = dyn_cast<BitCastInst>(Callee)) 910 if (IntrinsicInst *In = dyn_cast<IntrinsicInst>(BC->getOperand(0))) 911 if (In->getIntrinsicID() == Intrinsic::init_trampoline) 912 return transformCallThroughTrampoline(CS); 913 914 const PointerType *PTy = cast<PointerType>(Callee->getType()); 915 const FunctionType *FTy = cast<FunctionType>(PTy->getElementType()); 916 if (FTy->isVarArg()) { 917 int ix = FTy->getNumParams() + (isa<InvokeInst>(Callee) ? 3 : 1); 918 // See if we can optimize any arguments passed through the varargs area of 919 // the call. 920 for (CallSite::arg_iterator I = CS.arg_begin()+FTy->getNumParams(), 921 E = CS.arg_end(); I != E; ++I, ++ix) { 922 CastInst *CI = dyn_cast<CastInst>(*I); 923 if (CI && isSafeToEliminateVarargsCast(CS, CI, TD, ix)) { 924 *I = CI->getOperand(0); 925 Changed = true; 926 } 927 } 928 } 929 930 if (isa<InlineAsm>(Callee) && !CS.doesNotThrow()) { 931 // Inline asm calls cannot throw - mark them 'nounwind'. 932 CS.setDoesNotThrow(); 933 Changed = true; 934 } 935 936 // Try to optimize the call if possible, we require TargetData for most of 937 // this. None of these calls are seen as possibly dead so go ahead and 938 // delete the instruction now. 939 if (CallInst *CI = dyn_cast<CallInst>(CS.getInstruction())) { 940 Instruction *I = tryOptimizeCall(CI, TD); 941 // If we changed something return the result, etc. Otherwise let 942 // the fallthrough check. 943 if (I) return EraseInstFromFunction(*I); 944 } 945 946 return Changed ? CS.getInstruction() : 0; 947} 948 949// transformConstExprCastCall - If the callee is a constexpr cast of a function, 950// attempt to move the cast to the arguments of the call/invoke. 951// 952bool InstCombiner::transformConstExprCastCall(CallSite CS) { 953 if (!isa<ConstantExpr>(CS.getCalledValue())) return false; 954 ConstantExpr *CE = cast<ConstantExpr>(CS.getCalledValue()); 955 if (CE->getOpcode() != Instruction::BitCast || 956 !isa<Function>(CE->getOperand(0))) 957 return false; 958 Function *Callee = cast<Function>(CE->getOperand(0)); 959 Instruction *Caller = CS.getInstruction(); 960 const AttrListPtr &CallerPAL = CS.getAttributes(); 961 962 // Okay, this is a cast from a function to a different type. Unless doing so 963 // would cause a type conversion of one of our arguments, change this call to 964 // be a direct call with arguments casted to the appropriate types. 965 // 966 const FunctionType *FT = Callee->getFunctionType(); 967 const Type *OldRetTy = Caller->getType(); 968 const Type *NewRetTy = FT->getReturnType(); 969 970 if (NewRetTy->isStructTy()) 971 return false; // TODO: Handle multiple return values. 972 973 // Check to see if we are changing the return type... 974 if (OldRetTy != NewRetTy) { 975 if (Callee->isDeclaration() && 976 // Conversion is ok if changing from one pointer type to another or from 977 // a pointer to an integer of the same size. 978 !((OldRetTy->isPointerTy() || !TD || 979 OldRetTy == TD->getIntPtrType(Caller->getContext())) && 980 (NewRetTy->isPointerTy() || !TD || 981 NewRetTy == TD->getIntPtrType(Caller->getContext())))) 982 return false; // Cannot transform this return value. 983 984 if (!Caller->use_empty() && 985 // void -> non-void is handled specially 986 !NewRetTy->isVoidTy() && !CastInst::isCastable(NewRetTy, OldRetTy)) 987 return false; // Cannot transform this return value. 988 989 if (!CallerPAL.isEmpty() && !Caller->use_empty()) { 990 Attributes RAttrs = CallerPAL.getRetAttributes(); 991 if (RAttrs & Attribute::typeIncompatible(NewRetTy)) 992 return false; // Attribute not compatible with transformed value. 993 } 994 995 // If the callsite is an invoke instruction, and the return value is used by 996 // a PHI node in a successor, we cannot change the return type of the call 997 // because there is no place to put the cast instruction (without breaking 998 // the critical edge). Bail out in this case. 999 if (!Caller->use_empty()) 1000 if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) 1001 for (Value::use_iterator UI = II->use_begin(), E = II->use_end(); 1002 UI != E; ++UI) 1003 if (PHINode *PN = dyn_cast<PHINode>(*UI)) 1004 if (PN->getParent() == II->getNormalDest() || 1005 PN->getParent() == II->getUnwindDest()) 1006 return false; 1007 } 1008 1009 unsigned NumActualArgs = unsigned(CS.arg_end()-CS.arg_begin()); 1010 unsigned NumCommonArgs = std::min(FT->getNumParams(), NumActualArgs); 1011 1012 CallSite::arg_iterator AI = CS.arg_begin(); 1013 for (unsigned i = 0, e = NumCommonArgs; i != e; ++i, ++AI) { 1014 const Type *ParamTy = FT->getParamType(i); 1015 const Type *ActTy = (*AI)->getType(); 1016 1017 if (!CastInst::isCastable(ActTy, ParamTy)) 1018 return false; // Cannot transform this parameter value. 1019 1020 if (CallerPAL.getParamAttributes(i + 1) 1021 & Attribute::typeIncompatible(ParamTy)) 1022 return false; // Attribute not compatible with transformed value. 1023 1024 // Converting from one pointer type to another or between a pointer and an 1025 // integer of the same size is safe even if we do not have a body. 1026 bool isConvertible = ActTy == ParamTy || 1027 (TD && ((ParamTy->isPointerTy() || 1028 ParamTy == TD->getIntPtrType(Caller->getContext())) && 1029 (ActTy->isPointerTy() || 1030 ActTy == TD->getIntPtrType(Caller->getContext())))); 1031 if (Callee->isDeclaration() && !isConvertible) return false; 1032 } 1033 1034 if (FT->getNumParams() < NumActualArgs && !FT->isVarArg() && 1035 Callee->isDeclaration()) 1036 return false; // Do not delete arguments unless we have a function body. 1037 1038 if (FT->getNumParams() < NumActualArgs && FT->isVarArg() && 1039 !CallerPAL.isEmpty()) 1040 // In this case we have more arguments than the new function type, but we 1041 // won't be dropping them. Check that these extra arguments have attributes 1042 // that are compatible with being a vararg call argument. 1043 for (unsigned i = CallerPAL.getNumSlots(); i; --i) { 1044 if (CallerPAL.getSlot(i - 1).Index <= FT->getNumParams()) 1045 break; 1046 Attributes PAttrs = CallerPAL.getSlot(i - 1).Attrs; 1047 if (PAttrs & Attribute::VarArgsIncompatible) 1048 return false; 1049 } 1050 1051 // Okay, we decided that this is a safe thing to do: go ahead and start 1052 // inserting cast instructions as necessary... 1053 std::vector<Value*> Args; 1054 Args.reserve(NumActualArgs); 1055 SmallVector<AttributeWithIndex, 8> attrVec; 1056 attrVec.reserve(NumCommonArgs); 1057 1058 // Get any return attributes. 1059 Attributes RAttrs = CallerPAL.getRetAttributes(); 1060 1061 // If the return value is not being used, the type may not be compatible 1062 // with the existing attributes. Wipe out any problematic attributes. 1063 RAttrs &= ~Attribute::typeIncompatible(NewRetTy); 1064 1065 // Add the new return attributes. 1066 if (RAttrs) 1067 attrVec.push_back(AttributeWithIndex::get(0, RAttrs)); 1068 1069 AI = CS.arg_begin(); 1070 for (unsigned i = 0; i != NumCommonArgs; ++i, ++AI) { 1071 const Type *ParamTy = FT->getParamType(i); 1072 if ((*AI)->getType() == ParamTy) { 1073 Args.push_back(*AI); 1074 } else { 1075 Instruction::CastOps opcode = CastInst::getCastOpcode(*AI, 1076 false, ParamTy, false); 1077 Args.push_back(Builder->CreateCast(opcode, *AI, ParamTy, "tmp")); 1078 } 1079 1080 // Add any parameter attributes. 1081 if (Attributes PAttrs = CallerPAL.getParamAttributes(i + 1)) 1082 attrVec.push_back(AttributeWithIndex::get(i + 1, PAttrs)); 1083 } 1084 1085 // If the function takes more arguments than the call was taking, add them 1086 // now. 1087 for (unsigned i = NumCommonArgs; i != FT->getNumParams(); ++i) 1088 Args.push_back(Constant::getNullValue(FT->getParamType(i))); 1089 1090 // If we are removing arguments to the function, emit an obnoxious warning. 1091 if (FT->getNumParams() < NumActualArgs) { 1092 if (!FT->isVarArg()) { 1093 errs() << "WARNING: While resolving call to function '" 1094 << Callee->getName() << "' arguments were dropped!\n"; 1095 } else { 1096 // Add all of the arguments in their promoted form to the arg list. 1097 for (unsigned i = FT->getNumParams(); i != NumActualArgs; ++i, ++AI) { 1098 const Type *PTy = getPromotedType((*AI)->getType()); 1099 if (PTy != (*AI)->getType()) { 1100 // Must promote to pass through va_arg area! 1101 Instruction::CastOps opcode = 1102 CastInst::getCastOpcode(*AI, false, PTy, false); 1103 Args.push_back(Builder->CreateCast(opcode, *AI, PTy, "tmp")); 1104 } else { 1105 Args.push_back(*AI); 1106 } 1107 1108 // Add any parameter attributes. 1109 if (Attributes PAttrs = CallerPAL.getParamAttributes(i + 1)) 1110 attrVec.push_back(AttributeWithIndex::get(i + 1, PAttrs)); 1111 } 1112 } 1113 } 1114 1115 if (Attributes FnAttrs = CallerPAL.getFnAttributes()) 1116 attrVec.push_back(AttributeWithIndex::get(~0, FnAttrs)); 1117 1118 if (NewRetTy->isVoidTy()) 1119 Caller->setName(""); // Void type should not have a name. 1120 1121 const AttrListPtr &NewCallerPAL = AttrListPtr::get(attrVec.begin(), 1122 attrVec.end()); 1123 1124 Instruction *NC; 1125 if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) { 1126 NC = InvokeInst::Create(Callee, II->getNormalDest(), II->getUnwindDest(), 1127 Args.begin(), Args.end(), 1128 Caller->getName(), Caller); 1129 cast<InvokeInst>(NC)->setCallingConv(II->getCallingConv()); 1130 cast<InvokeInst>(NC)->setAttributes(NewCallerPAL); 1131 } else { 1132 NC = CallInst::Create(Callee, Args.begin(), Args.end(), 1133 Caller->getName(), Caller); 1134 CallInst *CI = cast<CallInst>(Caller); 1135 if (CI->isTailCall()) 1136 cast<CallInst>(NC)->setTailCall(); 1137 cast<CallInst>(NC)->setCallingConv(CI->getCallingConv()); 1138 cast<CallInst>(NC)->setAttributes(NewCallerPAL); 1139 } 1140 1141 // Insert a cast of the return type as necessary. 1142 Value *NV = NC; 1143 if (OldRetTy != NV->getType() && !Caller->use_empty()) { 1144 if (!NV->getType()->isVoidTy()) { 1145 Instruction::CastOps opcode = CastInst::getCastOpcode(NC, false, 1146 OldRetTy, false); 1147 NV = NC = CastInst::Create(opcode, NC, OldRetTy, "tmp"); 1148 1149 // If this is an invoke instruction, we should insert it after the first 1150 // non-phi, instruction in the normal successor block. 1151 if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) { 1152 BasicBlock::iterator I = II->getNormalDest()->getFirstNonPHI(); 1153 InsertNewInstBefore(NC, *I); 1154 } else { 1155 // Otherwise, it's a call, just insert cast right after the call instr 1156 InsertNewInstBefore(NC, *Caller); 1157 } 1158 Worklist.AddUsersToWorkList(*Caller); 1159 } else { 1160 NV = UndefValue::get(Caller->getType()); 1161 } 1162 } 1163 1164 1165 if (!Caller->use_empty()) 1166 Caller->replaceAllUsesWith(NV); 1167 1168 EraseInstFromFunction(*Caller); 1169 return true; 1170} 1171 1172// transformCallThroughTrampoline - Turn a call to a function created by the 1173// init_trampoline intrinsic into a direct call to the underlying function. 1174// 1175Instruction *InstCombiner::transformCallThroughTrampoline(CallSite CS) { 1176 Value *Callee = CS.getCalledValue(); 1177 const PointerType *PTy = cast<PointerType>(Callee->getType()); 1178 const FunctionType *FTy = cast<FunctionType>(PTy->getElementType()); 1179 const AttrListPtr &Attrs = CS.getAttributes(); 1180 1181 // If the call already has the 'nest' attribute somewhere then give up - 1182 // otherwise 'nest' would occur twice after splicing in the chain. 1183 if (Attrs.hasAttrSomewhere(Attribute::Nest)) 1184 return 0; 1185 1186 IntrinsicInst *Tramp = 1187 cast<IntrinsicInst>(cast<BitCastInst>(Callee)->getOperand(0)); 1188 1189 Function *NestF =cast<Function>(Tramp->getArgOperand(1)->stripPointerCasts()); 1190 const PointerType *NestFPTy = cast<PointerType>(NestF->getType()); 1191 const FunctionType *NestFTy = cast<FunctionType>(NestFPTy->getElementType()); 1192 1193 const AttrListPtr &NestAttrs = NestF->getAttributes(); 1194 if (!NestAttrs.isEmpty()) { 1195 unsigned NestIdx = 1; 1196 const Type *NestTy = 0; 1197 Attributes NestAttr = Attribute::None; 1198 1199 // Look for a parameter marked with the 'nest' attribute. 1200 for (FunctionType::param_iterator I = NestFTy->param_begin(), 1201 E = NestFTy->param_end(); I != E; ++NestIdx, ++I) 1202 if (NestAttrs.paramHasAttr(NestIdx, Attribute::Nest)) { 1203 // Record the parameter type and any other attributes. 1204 NestTy = *I; 1205 NestAttr = NestAttrs.getParamAttributes(NestIdx); 1206 break; 1207 } 1208 1209 if (NestTy) { 1210 Instruction *Caller = CS.getInstruction(); 1211 std::vector<Value*> NewArgs; 1212 NewArgs.reserve(unsigned(CS.arg_end()-CS.arg_begin())+1); 1213 1214 SmallVector<AttributeWithIndex, 8> NewAttrs; 1215 NewAttrs.reserve(Attrs.getNumSlots() + 1); 1216 1217 // Insert the nest argument into the call argument list, which may 1218 // mean appending it. Likewise for attributes. 1219 1220 // Add any result attributes. 1221 if (Attributes Attr = Attrs.getRetAttributes()) 1222 NewAttrs.push_back(AttributeWithIndex::get(0, Attr)); 1223 1224 { 1225 unsigned Idx = 1; 1226 CallSite::arg_iterator I = CS.arg_begin(), E = CS.arg_end(); 1227 do { 1228 if (Idx == NestIdx) { 1229 // Add the chain argument and attributes. 1230 Value *NestVal = Tramp->getArgOperand(2); 1231 if (NestVal->getType() != NestTy) 1232 NestVal = new BitCastInst(NestVal, NestTy, "nest", Caller); 1233 NewArgs.push_back(NestVal); 1234 NewAttrs.push_back(AttributeWithIndex::get(NestIdx, NestAttr)); 1235 } 1236 1237 if (I == E) 1238 break; 1239 1240 // Add the original argument and attributes. 1241 NewArgs.push_back(*I); 1242 if (Attributes Attr = Attrs.getParamAttributes(Idx)) 1243 NewAttrs.push_back 1244 (AttributeWithIndex::get(Idx + (Idx >= NestIdx), Attr)); 1245 1246 ++Idx, ++I; 1247 } while (1); 1248 } 1249 1250 // Add any function attributes. 1251 if (Attributes Attr = Attrs.getFnAttributes()) 1252 NewAttrs.push_back(AttributeWithIndex::get(~0, Attr)); 1253 1254 // The trampoline may have been bitcast to a bogus type (FTy). 1255 // Handle this by synthesizing a new function type, equal to FTy 1256 // with the chain parameter inserted. 1257 1258 std::vector<const Type*> NewTypes; 1259 NewTypes.reserve(FTy->getNumParams()+1); 1260 1261 // Insert the chain's type into the list of parameter types, which may 1262 // mean appending it. 1263 { 1264 unsigned Idx = 1; 1265 FunctionType::param_iterator I = FTy->param_begin(), 1266 E = FTy->param_end(); 1267 1268 do { 1269 if (Idx == NestIdx) 1270 // Add the chain's type. 1271 NewTypes.push_back(NestTy); 1272 1273 if (I == E) 1274 break; 1275 1276 // Add the original type. 1277 NewTypes.push_back(*I); 1278 1279 ++Idx, ++I; 1280 } while (1); 1281 } 1282 1283 // Replace the trampoline call with a direct call. Let the generic 1284 // code sort out any function type mismatches. 1285 FunctionType *NewFTy = FunctionType::get(FTy->getReturnType(), NewTypes, 1286 FTy->isVarArg()); 1287 Constant *NewCallee = 1288 NestF->getType() == PointerType::getUnqual(NewFTy) ? 1289 NestF : ConstantExpr::getBitCast(NestF, 1290 PointerType::getUnqual(NewFTy)); 1291 const AttrListPtr &NewPAL = AttrListPtr::get(NewAttrs.begin(), 1292 NewAttrs.end()); 1293 1294 Instruction *NewCaller; 1295 if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) { 1296 NewCaller = InvokeInst::Create(NewCallee, 1297 II->getNormalDest(), II->getUnwindDest(), 1298 NewArgs.begin(), NewArgs.end(), 1299 Caller->getName(), Caller); 1300 cast<InvokeInst>(NewCaller)->setCallingConv(II->getCallingConv()); 1301 cast<InvokeInst>(NewCaller)->setAttributes(NewPAL); 1302 } else { 1303 NewCaller = CallInst::Create(NewCallee, NewArgs.begin(), NewArgs.end(), 1304 Caller->getName(), Caller); 1305 if (cast<CallInst>(Caller)->isTailCall()) 1306 cast<CallInst>(NewCaller)->setTailCall(); 1307 cast<CallInst>(NewCaller)-> 1308 setCallingConv(cast<CallInst>(Caller)->getCallingConv()); 1309 cast<CallInst>(NewCaller)->setAttributes(NewPAL); 1310 } 1311 if (!Caller->getType()->isVoidTy()) 1312 Caller->replaceAllUsesWith(NewCaller); 1313 Caller->eraseFromParent(); 1314 Worklist.Remove(Caller); 1315 return 0; 1316 } 1317 } 1318 1319 // Replace the trampoline call with a direct call. Since there is no 'nest' 1320 // parameter, there is no need to adjust the argument list. Let the generic 1321 // code sort out any function type mismatches. 1322 Constant *NewCallee = 1323 NestF->getType() == PTy ? NestF : 1324 ConstantExpr::getBitCast(NestF, PTy); 1325 CS.setCalledFunction(NewCallee); 1326 return CS.getInstruction(); 1327} 1328 1329