InstCombineCalls.cpp revision f1ac465b67d5fc11a0d9cd09b98ceb4ffa75dd97
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" 20#include "llvm/Transforms/Utils/Local.h" 21using namespace llvm; 22 23/// getPromotedType - Return the specified type promoted as it would be to pass 24/// though a va_arg area. 25static const Type *getPromotedType(const Type *Ty) { 26 if (const IntegerType* ITy = dyn_cast<IntegerType>(Ty)) { 27 if (ITy->getBitWidth() < 32) 28 return Type::getInt32Ty(Ty->getContext()); 29 } 30 return Ty; 31} 32 33 34Instruction *InstCombiner::SimplifyMemTransfer(MemIntrinsic *MI) { 35 unsigned DstAlign = getKnownAlignment(MI->getArgOperand(0), TD); 36 unsigned SrcAlign = getKnownAlignment(MI->getArgOperand(1), TD); 37 unsigned MinAlign = std::min(DstAlign, SrcAlign); 38 unsigned CopyAlign = MI->getAlignment(); 39 40 if (CopyAlign < MinAlign) { 41 MI->setAlignment(ConstantInt::get(MI->getAlignmentType(), 42 MinAlign, false)); 43 return MI; 44 } 45 46 // If MemCpyInst length is 1/2/4/8 bytes then replace memcpy with 47 // load/store. 48 ConstantInt *MemOpLength = dyn_cast<ConstantInt>(MI->getArgOperand(2)); 49 if (MemOpLength == 0) return 0; 50 51 // Source and destination pointer types are always "i8*" for intrinsic. See 52 // if the size is something we can handle with a single primitive load/store. 53 // A single load+store correctly handles overlapping memory in the memmove 54 // case. 55 unsigned Size = MemOpLength->getZExtValue(); 56 if (Size == 0) return MI; // Delete this mem transfer. 57 58 if (Size > 8 || (Size&(Size-1))) 59 return 0; // If not 1/2/4/8 bytes, exit. 60 61 // Use an integer load+store unless we can find something better. 62 unsigned SrcAddrSp = 63 cast<PointerType>(MI->getArgOperand(1)->getType())->getAddressSpace(); 64 unsigned DstAddrSp = 65 cast<PointerType>(MI->getArgOperand(0)->getType())->getAddressSpace(); 66 67 const IntegerType* IntType = IntegerType::get(MI->getContext(), Size<<3); 68 Type *NewSrcPtrTy = PointerType::get(IntType, SrcAddrSp); 69 Type *NewDstPtrTy = PointerType::get(IntType, DstAddrSp); 70 71 // Memcpy forces the use of i8* for the source and destination. That means 72 // that if you're using memcpy to move one double around, you'll get a cast 73 // from double* to i8*. We'd much rather use a double load+store rather than 74 // an i64 load+store, here because this improves the odds that the source or 75 // dest address will be promotable. See if we can find a better type than the 76 // integer datatype. 77 Value *StrippedDest = MI->getArgOperand(0)->stripPointerCasts(); 78 if (StrippedDest != MI->getArgOperand(0)) { 79 const Type *SrcETy = cast<PointerType>(StrippedDest->getType()) 80 ->getElementType(); 81 if (TD && SrcETy->isSized() && TD->getTypeStoreSize(SrcETy) == Size) { 82 // The SrcETy might be something like {{{double}}} or [1 x double]. Rip 83 // down through these levels if so. 84 while (!SrcETy->isSingleValueType()) { 85 if (const StructType *STy = dyn_cast<StructType>(SrcETy)) { 86 if (STy->getNumElements() == 1) 87 SrcETy = STy->getElementType(0); 88 else 89 break; 90 } else if (const ArrayType *ATy = dyn_cast<ArrayType>(SrcETy)) { 91 if (ATy->getNumElements() == 1) 92 SrcETy = ATy->getElementType(); 93 else 94 break; 95 } else 96 break; 97 } 98 99 if (SrcETy->isSingleValueType()) { 100 NewSrcPtrTy = PointerType::get(SrcETy, SrcAddrSp); 101 NewDstPtrTy = PointerType::get(SrcETy, DstAddrSp); 102 } 103 } 104 } 105 106 107 // If the memcpy/memmove provides better alignment info than we can 108 // infer, use it. 109 SrcAlign = std::max(SrcAlign, CopyAlign); 110 DstAlign = std::max(DstAlign, CopyAlign); 111 112 Value *Src = Builder->CreateBitCast(MI->getArgOperand(1), NewSrcPtrTy); 113 Value *Dest = Builder->CreateBitCast(MI->getArgOperand(0), NewDstPtrTy); 114 LoadInst *L = Builder->CreateLoad(Src, MI->isVolatile()); 115 L->setAlignment(SrcAlign); 116 StoreInst *S = Builder->CreateStore(L, Dest, MI->isVolatile()); 117 S->setAlignment(DstAlign); 118 119 // Set the size of the copy to 0, it will be deleted on the next iteration. 120 MI->setArgOperand(2, Constant::getNullValue(MemOpLength->getType())); 121 return MI; 122} 123 124Instruction *InstCombiner::SimplifyMemSet(MemSetInst *MI) { 125 unsigned Alignment = getKnownAlignment(MI->getDest(), TD); 126 if (MI->getAlignment() < Alignment) { 127 MI->setAlignment(ConstantInt::get(MI->getAlignmentType(), 128 Alignment, false)); 129 return MI; 130 } 131 132 // Extract the length and alignment and fill if they are constant. 133 ConstantInt *LenC = dyn_cast<ConstantInt>(MI->getLength()); 134 ConstantInt *FillC = dyn_cast<ConstantInt>(MI->getValue()); 135 if (!LenC || !FillC || !FillC->getType()->isIntegerTy(8)) 136 return 0; 137 uint64_t Len = LenC->getZExtValue(); 138 Alignment = MI->getAlignment(); 139 140 // If the length is zero, this is a no-op 141 if (Len == 0) return MI; // memset(d,c,0,a) -> noop 142 143 // memset(s,c,n) -> store s, c (for n=1,2,4,8) 144 if (Len <= 8 && isPowerOf2_32((uint32_t)Len)) { 145 const Type *ITy = IntegerType::get(MI->getContext(), Len*8); // n=1 -> i8. 146 147 Value *Dest = MI->getDest(); 148 unsigned DstAddrSp = cast<PointerType>(Dest->getType())->getAddressSpace(); 149 Type *NewDstPtrTy = PointerType::get(ITy, DstAddrSp); 150 Dest = Builder->CreateBitCast(Dest, NewDstPtrTy); 151 152 // Alignment 0 is identity for alignment 1 for memset, but not store. 153 if (Alignment == 0) Alignment = 1; 154 155 // Extract the fill value and store. 156 uint64_t Fill = FillC->getZExtValue()*0x0101010101010101ULL; 157 StoreInst *S = Builder->CreateStore(ConstantInt::get(ITy, Fill), Dest, 158 MI->isVolatile()); 159 S->setAlignment(Alignment); 160 161 // Set the size of the copy to 0, it will be deleted on the next iteration. 162 MI->setLength(Constant::getNullValue(LenC->getType())); 163 return MI; 164 } 165 166 return 0; 167} 168 169/// visitCallInst - CallInst simplification. This mostly only handles folding 170/// of intrinsic instructions. For normal calls, it allows visitCallSite to do 171/// the heavy lifting. 172/// 173Instruction *InstCombiner::visitCallInst(CallInst &CI) { 174 if (isFreeCall(&CI)) 175 return visitFree(CI); 176 if (isMalloc(&CI)) 177 return visitMalloc(CI); 178 179 // If the caller function is nounwind, mark the call as nounwind, even if the 180 // callee isn't. 181 if (CI.getParent()->getParent()->doesNotThrow() && 182 !CI.doesNotThrow()) { 183 CI.setDoesNotThrow(); 184 return &CI; 185 } 186 187 IntrinsicInst *II = dyn_cast<IntrinsicInst>(&CI); 188 if (!II) return visitCallSite(&CI); 189 190 // Intrinsics cannot occur in an invoke, so handle them here instead of in 191 // visitCallSite. 192 if (MemIntrinsic *MI = dyn_cast<MemIntrinsic>(II)) { 193 bool Changed = false; 194 195 // memmove/cpy/set of zero bytes is a noop. 196 if (Constant *NumBytes = dyn_cast<Constant>(MI->getLength())) { 197 if (NumBytes->isNullValue()) 198 return EraseInstFromFunction(CI); 199 200 if (ConstantInt *CI = dyn_cast<ConstantInt>(NumBytes)) 201 if (CI->getZExtValue() == 1) { 202 // Replace the instruction with just byte operations. We would 203 // transform other cases to loads/stores, but we don't know if 204 // alignment is sufficient. 205 } 206 } 207 208 // No other transformations apply to volatile transfers. 209 if (MI->isVolatile()) 210 return 0; 211 212 // If we have a memmove and the source operation is a constant global, 213 // then the source and dest pointers can't alias, so we can change this 214 // into a call to memcpy. 215 if (MemMoveInst *MMI = dyn_cast<MemMoveInst>(MI)) { 216 if (GlobalVariable *GVSrc = dyn_cast<GlobalVariable>(MMI->getSource())) 217 if (GVSrc->isConstant()) { 218 Module *M = CI.getParent()->getParent()->getParent(); 219 Intrinsic::ID MemCpyID = Intrinsic::memcpy; 220 const Type *Tys[3] = { CI.getArgOperand(0)->getType(), 221 CI.getArgOperand(1)->getType(), 222 CI.getArgOperand(2)->getType() }; 223 CI.setCalledFunction(Intrinsic::getDeclaration(M, MemCpyID, Tys, 3)); 224 Changed = true; 225 } 226 } 227 228 if (MemTransferInst *MTI = dyn_cast<MemTransferInst>(MI)) { 229 // memmove(x,x,size) -> noop. 230 if (MTI->getSource() == MTI->getDest()) 231 return EraseInstFromFunction(CI); 232 } 233 234 // If we can determine a pointer alignment that is bigger than currently 235 // set, update the alignment. 236 if (isa<MemTransferInst>(MI)) { 237 if (Instruction *I = SimplifyMemTransfer(MI)) 238 return I; 239 } else if (MemSetInst *MSI = dyn_cast<MemSetInst>(MI)) { 240 if (Instruction *I = SimplifyMemSet(MSI)) 241 return I; 242 } 243 244 if (Changed) return II; 245 } 246 247 switch (II->getIntrinsicID()) { 248 default: break; 249 case Intrinsic::objectsize: { 250 // We need target data for just about everything so depend on it. 251 if (!TD) break; 252 253 const Type *ReturnTy = CI.getType(); 254 uint64_t DontKnow = II->getArgOperand(1) == Builder->getTrue() ? 0 : -1ULL; 255 256 // Get to the real allocated thing and offset as fast as possible. 257 Value *Op1 = II->getArgOperand(0)->stripPointerCasts(); 258 259 uint64_t Offset = 0; 260 uint64_t Size = -1ULL; 261 262 // Try to look through constant GEPs. 263 if (GEPOperator *GEP = dyn_cast<GEPOperator>(Op1)) { 264 if (!GEP->hasAllConstantIndices()) break; 265 266 // Get the current byte offset into the thing. Use the original 267 // operand in case we're looking through a bitcast. 268 SmallVector<Value*, 8> Ops(GEP->idx_begin(), GEP->idx_end()); 269 Offset = TD->getIndexedOffset(GEP->getPointerOperandType(), 270 Ops.data(), Ops.size()); 271 272 Op1 = GEP->getPointerOperand()->stripPointerCasts(); 273 274 // Make sure we're not a constant offset from an external 275 // global. 276 if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Op1)) 277 if (!GV->hasDefinitiveInitializer()) break; 278 } 279 280 // If we've stripped down to a single global variable that we 281 // can know the size of then just return that. 282 if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Op1)) { 283 if (GV->hasDefinitiveInitializer()) { 284 Constant *C = GV->getInitializer(); 285 Size = TD->getTypeAllocSize(C->getType()); 286 } else { 287 // Can't determine size of the GV. 288 Constant *RetVal = ConstantInt::get(ReturnTy, DontKnow); 289 return ReplaceInstUsesWith(CI, RetVal); 290 } 291 } else if (AllocaInst *AI = dyn_cast<AllocaInst>(Op1)) { 292 // Get alloca size. 293 if (AI->getAllocatedType()->isSized()) { 294 Size = TD->getTypeAllocSize(AI->getAllocatedType()); 295 if (AI->isArrayAllocation()) { 296 const ConstantInt *C = dyn_cast<ConstantInt>(AI->getArraySize()); 297 if (!C) break; 298 Size *= C->getZExtValue(); 299 } 300 } 301 } else if (CallInst *MI = extractMallocCall(Op1)) { 302 // Get allocation size. 303 const Type* MallocType = getMallocAllocatedType(MI); 304 if (MallocType && MallocType->isSized()) 305 if (Value *NElems = getMallocArraySize(MI, TD, true)) 306 if (ConstantInt *NElements = dyn_cast<ConstantInt>(NElems)) 307 Size = NElements->getZExtValue() * TD->getTypeAllocSize(MallocType); 308 } 309 310 // Do not return "I don't know" here. Later optimization passes could 311 // make it possible to evaluate objectsize to a constant. 312 if (Size == -1ULL) 313 break; 314 315 if (Size < Offset) { 316 // Out of bound reference? Negative index normalized to large 317 // index? Just return "I don't know". 318 return ReplaceInstUsesWith(CI, ConstantInt::get(ReturnTy, DontKnow)); 319 } 320 return ReplaceInstUsesWith(CI, ConstantInt::get(ReturnTy, Size-Offset)); 321 } 322 case Intrinsic::bswap: 323 // bswap(bswap(x)) -> x 324 if (IntrinsicInst *Operand = dyn_cast<IntrinsicInst>(II->getArgOperand(0))) 325 if (Operand->getIntrinsicID() == Intrinsic::bswap) 326 return ReplaceInstUsesWith(CI, Operand->getArgOperand(0)); 327 328 // bswap(trunc(bswap(x))) -> trunc(lshr(x, c)) 329 if (TruncInst *TI = dyn_cast<TruncInst>(II->getArgOperand(0))) { 330 if (IntrinsicInst *Operand = dyn_cast<IntrinsicInst>(TI->getOperand(0))) 331 if (Operand->getIntrinsicID() == Intrinsic::bswap) { 332 unsigned C = Operand->getType()->getPrimitiveSizeInBits() - 333 TI->getType()->getPrimitiveSizeInBits(); 334 Value *CV = ConstantInt::get(Operand->getType(), C); 335 Value *V = Builder->CreateLShr(Operand->getArgOperand(0), CV); 336 return new TruncInst(V, TI->getType()); 337 } 338 } 339 340 break; 341 case Intrinsic::powi: 342 if (ConstantInt *Power = dyn_cast<ConstantInt>(II->getArgOperand(1))) { 343 // powi(x, 0) -> 1.0 344 if (Power->isZero()) 345 return ReplaceInstUsesWith(CI, ConstantFP::get(CI.getType(), 1.0)); 346 // powi(x, 1) -> x 347 if (Power->isOne()) 348 return ReplaceInstUsesWith(CI, II->getArgOperand(0)); 349 // powi(x, -1) -> 1/x 350 if (Power->isAllOnesValue()) 351 return BinaryOperator::CreateFDiv(ConstantFP::get(CI.getType(), 1.0), 352 II->getArgOperand(0)); 353 } 354 break; 355 case Intrinsic::cttz: { 356 // If all bits below the first known one are known zero, 357 // this value is constant. 358 const IntegerType *IT = dyn_cast<IntegerType>(II->getArgOperand(0)->getType()); 359 // FIXME: Try to simplify vectors of integers. 360 if (!IT) break; 361 uint32_t BitWidth = IT->getBitWidth(); 362 APInt KnownZero(BitWidth, 0); 363 APInt KnownOne(BitWidth, 0); 364 ComputeMaskedBits(II->getArgOperand(0), APInt::getAllOnesValue(BitWidth), 365 KnownZero, KnownOne); 366 unsigned TrailingZeros = KnownOne.countTrailingZeros(); 367 APInt Mask(APInt::getLowBitsSet(BitWidth, TrailingZeros)); 368 if ((Mask & KnownZero) == Mask) 369 return ReplaceInstUsesWith(CI, ConstantInt::get(IT, 370 APInt(BitWidth, TrailingZeros))); 371 372 } 373 break; 374 case Intrinsic::ctlz: { 375 // If all bits above the first known one are known zero, 376 // this value is constant. 377 const IntegerType *IT = dyn_cast<IntegerType>(II->getArgOperand(0)->getType()); 378 // FIXME: Try to simplify vectors of integers. 379 if (!IT) break; 380 uint32_t BitWidth = IT->getBitWidth(); 381 APInt KnownZero(BitWidth, 0); 382 APInt KnownOne(BitWidth, 0); 383 ComputeMaskedBits(II->getArgOperand(0), APInt::getAllOnesValue(BitWidth), 384 KnownZero, KnownOne); 385 unsigned LeadingZeros = KnownOne.countLeadingZeros(); 386 APInt Mask(APInt::getHighBitsSet(BitWidth, LeadingZeros)); 387 if ((Mask & KnownZero) == Mask) 388 return ReplaceInstUsesWith(CI, ConstantInt::get(IT, 389 APInt(BitWidth, LeadingZeros))); 390 391 } 392 break; 393 case Intrinsic::uadd_with_overflow: { 394 Value *LHS = II->getArgOperand(0), *RHS = II->getArgOperand(1); 395 const IntegerType *IT = cast<IntegerType>(II->getArgOperand(0)->getType()); 396 uint32_t BitWidth = IT->getBitWidth(); 397 APInt Mask = APInt::getSignBit(BitWidth); 398 APInt LHSKnownZero(BitWidth, 0); 399 APInt LHSKnownOne(BitWidth, 0); 400 ComputeMaskedBits(LHS, Mask, LHSKnownZero, LHSKnownOne); 401 bool LHSKnownNegative = LHSKnownOne[BitWidth - 1]; 402 bool LHSKnownPositive = LHSKnownZero[BitWidth - 1]; 403 404 if (LHSKnownNegative || LHSKnownPositive) { 405 APInt RHSKnownZero(BitWidth, 0); 406 APInt RHSKnownOne(BitWidth, 0); 407 ComputeMaskedBits(RHS, Mask, RHSKnownZero, RHSKnownOne); 408 bool RHSKnownNegative = RHSKnownOne[BitWidth - 1]; 409 bool RHSKnownPositive = RHSKnownZero[BitWidth - 1]; 410 if (LHSKnownNegative && RHSKnownNegative) { 411 // The sign bit is set in both cases: this MUST overflow. 412 // Create a simple add instruction, and insert it into the struct. 413 Value *Add = Builder->CreateAdd(LHS, RHS); 414 Add->takeName(&CI); 415 Constant *V[] = { 416 UndefValue::get(LHS->getType()), 417 ConstantInt::getTrue(II->getContext()) 418 }; 419 const StructType *ST = cast<StructType>(II->getType()); 420 Constant *Struct = ConstantStruct::get(ST, V); 421 return InsertValueInst::Create(Struct, Add, 0); 422 } 423 424 if (LHSKnownPositive && RHSKnownPositive) { 425 // The sign bit is clear in both cases: this CANNOT overflow. 426 // Create a simple add instruction, and insert it into the struct. 427 Value *Add = Builder->CreateNUWAdd(LHS, RHS); 428 Add->takeName(&CI); 429 Constant *V[] = { 430 UndefValue::get(LHS->getType()), 431 ConstantInt::getFalse(II->getContext()) 432 }; 433 const StructType *ST = cast<StructType>(II->getType()); 434 Constant *Struct = ConstantStruct::get(ST, V); 435 return InsertValueInst::Create(Struct, Add, 0); 436 } 437 } 438 } 439 // FALL THROUGH uadd into sadd 440 case Intrinsic::sadd_with_overflow: 441 // Canonicalize constants into the RHS. 442 if (isa<Constant>(II->getArgOperand(0)) && 443 !isa<Constant>(II->getArgOperand(1))) { 444 Value *LHS = II->getArgOperand(0); 445 II->setArgOperand(0, II->getArgOperand(1)); 446 II->setArgOperand(1, LHS); 447 return II; 448 } 449 450 // X + undef -> undef 451 if (isa<UndefValue>(II->getArgOperand(1))) 452 return ReplaceInstUsesWith(CI, UndefValue::get(II->getType())); 453 454 if (ConstantInt *RHS = dyn_cast<ConstantInt>(II->getArgOperand(1))) { 455 // X + 0 -> {X, false} 456 if (RHS->isZero()) { 457 Constant *V[] = { 458 UndefValue::get(II->getArgOperand(0)->getType()), 459 ConstantInt::getFalse(II->getContext()) 460 }; 461 Constant *Struct = 462 ConstantStruct::get(cast<StructType>(II->getType()), V); 463 return InsertValueInst::Create(Struct, II->getArgOperand(0), 0); 464 } 465 } 466 break; 467 case Intrinsic::usub_with_overflow: 468 case Intrinsic::ssub_with_overflow: 469 // undef - X -> undef 470 // X - undef -> undef 471 if (isa<UndefValue>(II->getArgOperand(0)) || 472 isa<UndefValue>(II->getArgOperand(1))) 473 return ReplaceInstUsesWith(CI, UndefValue::get(II->getType())); 474 475 if (ConstantInt *RHS = dyn_cast<ConstantInt>(II->getArgOperand(1))) { 476 // X - 0 -> {X, false} 477 if (RHS->isZero()) { 478 Constant *V[] = { 479 UndefValue::get(II->getArgOperand(0)->getType()), 480 ConstantInt::getFalse(II->getContext()) 481 }; 482 Constant *Struct = 483 ConstantStruct::get(cast<StructType>(II->getType()), V); 484 return InsertValueInst::Create(Struct, II->getArgOperand(0), 0); 485 } 486 } 487 break; 488 case Intrinsic::umul_with_overflow: { 489 Value *LHS = II->getArgOperand(0), *RHS = II->getArgOperand(1); 490 unsigned BitWidth = cast<IntegerType>(LHS->getType())->getBitWidth(); 491 APInt Mask = APInt::getAllOnesValue(BitWidth); 492 493 APInt LHSKnownZero(BitWidth, 0); 494 APInt LHSKnownOne(BitWidth, 0); 495 ComputeMaskedBits(LHS, Mask, LHSKnownZero, LHSKnownOne); 496 APInt RHSKnownZero(BitWidth, 0); 497 APInt RHSKnownOne(BitWidth, 0); 498 ComputeMaskedBits(RHS, Mask, RHSKnownZero, RHSKnownOne); 499 500 // Get the largest possible values for each operand. 501 APInt LHSMax = ~LHSKnownZero; 502 APInt RHSMax = ~RHSKnownZero; 503 504 // If multiplying the maximum values does not overflow then we can turn 505 // this into a plain NUW mul. 506 bool Overflow; 507 LHSMax.umul_ov(RHSMax, Overflow); 508 if (!Overflow) { 509 Value *Mul = Builder->CreateNUWMul(LHS, RHS, "umul_with_overflow"); 510 Constant *V[] = { 511 UndefValue::get(LHS->getType()), 512 Builder->getFalse() 513 }; 514 Constant *Struct = ConstantStruct::get(cast<StructType>(II->getType()),V); 515 return InsertValueInst::Create(Struct, Mul, 0); 516 } 517 } // FALL THROUGH 518 case Intrinsic::smul_with_overflow: 519 // Canonicalize constants into the RHS. 520 if (isa<Constant>(II->getArgOperand(0)) && 521 !isa<Constant>(II->getArgOperand(1))) { 522 Value *LHS = II->getArgOperand(0); 523 II->setArgOperand(0, II->getArgOperand(1)); 524 II->setArgOperand(1, LHS); 525 return II; 526 } 527 528 // X * undef -> undef 529 if (isa<UndefValue>(II->getArgOperand(1))) 530 return ReplaceInstUsesWith(CI, UndefValue::get(II->getType())); 531 532 if (ConstantInt *RHSI = dyn_cast<ConstantInt>(II->getArgOperand(1))) { 533 // X*0 -> {0, false} 534 if (RHSI->isZero()) 535 return ReplaceInstUsesWith(CI, Constant::getNullValue(II->getType())); 536 537 // X * 1 -> {X, false} 538 if (RHSI->equalsInt(1)) { 539 Constant *V[] = { 540 UndefValue::get(II->getArgOperand(0)->getType()), 541 ConstantInt::getFalse(II->getContext()) 542 }; 543 Constant *Struct = 544 ConstantStruct::get(cast<StructType>(II->getType()), V); 545 return InsertValueInst::Create(Struct, II->getArgOperand(0), 0); 546 } 547 } 548 break; 549 case Intrinsic::ppc_altivec_lvx: 550 case Intrinsic::ppc_altivec_lvxl: 551 // Turn PPC lvx -> load if the pointer is known aligned. 552 if (getOrEnforceKnownAlignment(II->getArgOperand(0), 16, TD) >= 16) { 553 Value *Ptr = Builder->CreateBitCast(II->getArgOperand(0), 554 PointerType::getUnqual(II->getType())); 555 return new LoadInst(Ptr); 556 } 557 break; 558 case Intrinsic::ppc_altivec_stvx: 559 case Intrinsic::ppc_altivec_stvxl: 560 // Turn stvx -> store if the pointer is known aligned. 561 if (getOrEnforceKnownAlignment(II->getArgOperand(1), 16, TD) >= 16) { 562 const Type *OpPtrTy = 563 PointerType::getUnqual(II->getArgOperand(0)->getType()); 564 Value *Ptr = Builder->CreateBitCast(II->getArgOperand(1), OpPtrTy); 565 return new StoreInst(II->getArgOperand(0), Ptr); 566 } 567 break; 568 case Intrinsic::x86_sse_storeu_ps: 569 case Intrinsic::x86_sse2_storeu_pd: 570 case Intrinsic::x86_sse2_storeu_dq: 571 // Turn X86 storeu -> store if the pointer is known aligned. 572 if (getOrEnforceKnownAlignment(II->getArgOperand(0), 16, TD) >= 16) { 573 const Type *OpPtrTy = 574 PointerType::getUnqual(II->getArgOperand(1)->getType()); 575 Value *Ptr = Builder->CreateBitCast(II->getArgOperand(0), OpPtrTy); 576 return new StoreInst(II->getArgOperand(1), Ptr); 577 } 578 break; 579 580 case Intrinsic::x86_sse_cvtss2si: 581 case Intrinsic::x86_sse_cvtss2si64: 582 case Intrinsic::x86_sse_cvttss2si: 583 case Intrinsic::x86_sse_cvttss2si64: 584 case Intrinsic::x86_sse2_cvtsd2si: 585 case Intrinsic::x86_sse2_cvtsd2si64: 586 case Intrinsic::x86_sse2_cvttsd2si: 587 case Intrinsic::x86_sse2_cvttsd2si64: { 588 // These intrinsics only demand the 0th element of their input vectors. If 589 // we can simplify the input based on that, do so now. 590 unsigned VWidth = 591 cast<VectorType>(II->getArgOperand(0)->getType())->getNumElements(); 592 APInt DemandedElts(VWidth, 1); 593 APInt UndefElts(VWidth, 0); 594 if (Value *V = SimplifyDemandedVectorElts(II->getArgOperand(0), 595 DemandedElts, UndefElts)) { 596 II->setArgOperand(0, V); 597 return II; 598 } 599 break; 600 } 601 602 603 case Intrinsic::x86_sse41_pmovsxbw: 604 case Intrinsic::x86_sse41_pmovsxwd: 605 case Intrinsic::x86_sse41_pmovsxdq: 606 case Intrinsic::x86_sse41_pmovzxbw: 607 case Intrinsic::x86_sse41_pmovzxwd: 608 case Intrinsic::x86_sse41_pmovzxdq: { 609 // pmov{s|z}x ignores the upper half of their input vectors. 610 unsigned VWidth = 611 cast<VectorType>(II->getArgOperand(0)->getType())->getNumElements(); 612 unsigned LowHalfElts = VWidth / 2; 613 APInt InputDemandedElts(APInt::getBitsSet(VWidth, 0, LowHalfElts)); 614 APInt UndefElts(VWidth, 0); 615 if (Value *TmpV = SimplifyDemandedVectorElts(II->getArgOperand(0), 616 InputDemandedElts, 617 UndefElts)) { 618 II->setArgOperand(0, TmpV); 619 return II; 620 } 621 break; 622 } 623 624 case Intrinsic::ppc_altivec_vperm: 625 // Turn vperm(V1,V2,mask) -> shuffle(V1,V2,mask) if mask is a constant. 626 if (ConstantVector *Mask = dyn_cast<ConstantVector>(II->getArgOperand(2))) { 627 assert(Mask->getNumOperands() == 16 && "Bad type for intrinsic!"); 628 629 // Check that all of the elements are integer constants or undefs. 630 bool AllEltsOk = true; 631 for (unsigned i = 0; i != 16; ++i) { 632 if (!isa<ConstantInt>(Mask->getOperand(i)) && 633 !isa<UndefValue>(Mask->getOperand(i))) { 634 AllEltsOk = false; 635 break; 636 } 637 } 638 639 if (AllEltsOk) { 640 // Cast the input vectors to byte vectors. 641 Value *Op0 = Builder->CreateBitCast(II->getArgOperand(0), 642 Mask->getType()); 643 Value *Op1 = Builder->CreateBitCast(II->getArgOperand(1), 644 Mask->getType()); 645 Value *Result = UndefValue::get(Op0->getType()); 646 647 // Only extract each element once. 648 Value *ExtractedElts[32]; 649 memset(ExtractedElts, 0, sizeof(ExtractedElts)); 650 651 for (unsigned i = 0; i != 16; ++i) { 652 if (isa<UndefValue>(Mask->getOperand(i))) 653 continue; 654 unsigned Idx=cast<ConstantInt>(Mask->getOperand(i))->getZExtValue(); 655 Idx &= 31; // Match the hardware behavior. 656 657 if (ExtractedElts[Idx] == 0) { 658 ExtractedElts[Idx] = 659 Builder->CreateExtractElement(Idx < 16 ? Op0 : Op1, 660 ConstantInt::get(Type::getInt32Ty(II->getContext()), 661 Idx&15, false), "tmp"); 662 } 663 664 // Insert this value into the result vector. 665 Result = Builder->CreateInsertElement(Result, ExtractedElts[Idx], 666 ConstantInt::get(Type::getInt32Ty(II->getContext()), 667 i, false), "tmp"); 668 } 669 return CastInst::Create(Instruction::BitCast, Result, CI.getType()); 670 } 671 } 672 break; 673 674 case Intrinsic::arm_neon_vld1: 675 case Intrinsic::arm_neon_vld2: 676 case Intrinsic::arm_neon_vld3: 677 case Intrinsic::arm_neon_vld4: 678 case Intrinsic::arm_neon_vld2lane: 679 case Intrinsic::arm_neon_vld3lane: 680 case Intrinsic::arm_neon_vld4lane: 681 case Intrinsic::arm_neon_vst1: 682 case Intrinsic::arm_neon_vst2: 683 case Intrinsic::arm_neon_vst3: 684 case Intrinsic::arm_neon_vst4: 685 case Intrinsic::arm_neon_vst2lane: 686 case Intrinsic::arm_neon_vst3lane: 687 case Intrinsic::arm_neon_vst4lane: { 688 unsigned MemAlign = getKnownAlignment(II->getArgOperand(0), TD); 689 unsigned AlignArg = II->getNumArgOperands() - 1; 690 ConstantInt *IntrAlign = dyn_cast<ConstantInt>(II->getArgOperand(AlignArg)); 691 if (IntrAlign && IntrAlign->getZExtValue() < MemAlign) { 692 II->setArgOperand(AlignArg, 693 ConstantInt::get(Type::getInt32Ty(II->getContext()), 694 MemAlign, false)); 695 return II; 696 } 697 break; 698 } 699 700 case Intrinsic::stackrestore: { 701 // If the save is right next to the restore, remove the restore. This can 702 // happen when variable allocas are DCE'd. 703 if (IntrinsicInst *SS = dyn_cast<IntrinsicInst>(II->getArgOperand(0))) { 704 if (SS->getIntrinsicID() == Intrinsic::stacksave) { 705 BasicBlock::iterator BI = SS; 706 if (&*++BI == II) 707 return EraseInstFromFunction(CI); 708 } 709 } 710 711 // Scan down this block to see if there is another stack restore in the 712 // same block without an intervening call/alloca. 713 BasicBlock::iterator BI = II; 714 TerminatorInst *TI = II->getParent()->getTerminator(); 715 bool CannotRemove = false; 716 for (++BI; &*BI != TI; ++BI) { 717 if (isa<AllocaInst>(BI) || isMalloc(BI)) { 718 CannotRemove = true; 719 break; 720 } 721 if (CallInst *BCI = dyn_cast<CallInst>(BI)) { 722 if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(BCI)) { 723 // If there is a stackrestore below this one, remove this one. 724 if (II->getIntrinsicID() == Intrinsic::stackrestore) 725 return EraseInstFromFunction(CI); 726 // Otherwise, ignore the intrinsic. 727 } else { 728 // If we found a non-intrinsic call, we can't remove the stack 729 // restore. 730 CannotRemove = true; 731 break; 732 } 733 } 734 } 735 736 // If the stack restore is in a return/unwind block and if there are no 737 // allocas or calls between the restore and the return, nuke the restore. 738 if (!CannotRemove && (isa<ReturnInst>(TI) || isa<UnwindInst>(TI))) 739 return EraseInstFromFunction(CI); 740 break; 741 } 742 } 743 744 return visitCallSite(II); 745} 746 747// InvokeInst simplification 748// 749Instruction *InstCombiner::visitInvokeInst(InvokeInst &II) { 750 return visitCallSite(&II); 751} 752 753/// isSafeToEliminateVarargsCast - If this cast does not affect the value 754/// passed through the varargs area, we can eliminate the use of the cast. 755static bool isSafeToEliminateVarargsCast(const CallSite CS, 756 const CastInst * const CI, 757 const TargetData * const TD, 758 const int ix) { 759 if (!CI->isLosslessCast()) 760 return false; 761 762 // The size of ByVal arguments is derived from the type, so we 763 // can't change to a type with a different size. If the size were 764 // passed explicitly we could avoid this check. 765 if (!CS.paramHasAttr(ix, Attribute::ByVal)) 766 return true; 767 768 const Type* SrcTy = 769 cast<PointerType>(CI->getOperand(0)->getType())->getElementType(); 770 const Type* DstTy = cast<PointerType>(CI->getType())->getElementType(); 771 if (!SrcTy->isSized() || !DstTy->isSized()) 772 return false; 773 if (!TD || TD->getTypeAllocSize(SrcTy) != TD->getTypeAllocSize(DstTy)) 774 return false; 775 return true; 776} 777 778namespace { 779class InstCombineFortifiedLibCalls : public SimplifyFortifiedLibCalls { 780 InstCombiner *IC; 781protected: 782 void replaceCall(Value *With) { 783 NewInstruction = IC->ReplaceInstUsesWith(*CI, With); 784 } 785 bool isFoldable(unsigned SizeCIOp, unsigned SizeArgOp, bool isString) const { 786 if (CI->getArgOperand(SizeCIOp) == CI->getArgOperand(SizeArgOp)) 787 return true; 788 if (ConstantInt *SizeCI = 789 dyn_cast<ConstantInt>(CI->getArgOperand(SizeCIOp))) { 790 if (SizeCI->isAllOnesValue()) 791 return true; 792 if (isString) { 793 uint64_t Len = GetStringLength(CI->getArgOperand(SizeArgOp)); 794 // If the length is 0 we don't know how long it is and so we can't 795 // remove the check. 796 if (Len == 0) return false; 797 return SizeCI->getZExtValue() >= Len; 798 } 799 if (ConstantInt *Arg = dyn_cast<ConstantInt>( 800 CI->getArgOperand(SizeArgOp))) 801 return SizeCI->getZExtValue() >= Arg->getZExtValue(); 802 } 803 return false; 804 } 805public: 806 InstCombineFortifiedLibCalls(InstCombiner *IC) : IC(IC), NewInstruction(0) { } 807 Instruction *NewInstruction; 808}; 809} // end anonymous namespace 810 811// Try to fold some different type of calls here. 812// Currently we're only working with the checking functions, memcpy_chk, 813// mempcpy_chk, memmove_chk, memset_chk, strcpy_chk, stpcpy_chk, strncpy_chk, 814// strcat_chk and strncat_chk. 815Instruction *InstCombiner::tryOptimizeCall(CallInst *CI, const TargetData *TD) { 816 if (CI->getCalledFunction() == 0) return 0; 817 818 InstCombineFortifiedLibCalls Simplifier(this); 819 Simplifier.fold(CI, TD); 820 return Simplifier.NewInstruction; 821} 822 823// visitCallSite - Improvements for call and invoke instructions. 824// 825Instruction *InstCombiner::visitCallSite(CallSite CS) { 826 bool Changed = false; 827 828 // If the callee is a pointer to a function, attempt to move any casts to the 829 // arguments of the call/invoke. 830 Value *Callee = CS.getCalledValue(); 831 if (!isa<Function>(Callee) && transformConstExprCastCall(CS)) 832 return 0; 833 834 if (Function *CalleeF = dyn_cast<Function>(Callee)) 835 // If the call and callee calling conventions don't match, this call must 836 // be unreachable, as the call is undefined. 837 if (CalleeF->getCallingConv() != CS.getCallingConv() && 838 // Only do this for calls to a function with a body. A prototype may 839 // not actually end up matching the implementation's calling conv for a 840 // variety of reasons (e.g. it may be written in assembly). 841 !CalleeF->isDeclaration()) { 842 Instruction *OldCall = CS.getInstruction(); 843 new StoreInst(ConstantInt::getTrue(Callee->getContext()), 844 UndefValue::get(Type::getInt1PtrTy(Callee->getContext())), 845 OldCall); 846 // If OldCall dues not return void then replaceAllUsesWith undef. 847 // This allows ValueHandlers and custom metadata to adjust itself. 848 if (!OldCall->getType()->isVoidTy()) 849 ReplaceInstUsesWith(*OldCall, UndefValue::get(OldCall->getType())); 850 if (isa<CallInst>(OldCall)) 851 return EraseInstFromFunction(*OldCall); 852 853 // We cannot remove an invoke, because it would change the CFG, just 854 // change the callee to a null pointer. 855 cast<InvokeInst>(OldCall)->setCalledFunction( 856 Constant::getNullValue(CalleeF->getType())); 857 return 0; 858 } 859 860 if (isa<ConstantPointerNull>(Callee) || isa<UndefValue>(Callee)) { 861 // This instruction is not reachable, just remove it. We insert a store to 862 // undef so that we know that this code is not reachable, despite the fact 863 // that we can't modify the CFG here. 864 new StoreInst(ConstantInt::getTrue(Callee->getContext()), 865 UndefValue::get(Type::getInt1PtrTy(Callee->getContext())), 866 CS.getInstruction()); 867 868 // If CS does not return void then replaceAllUsesWith undef. 869 // This allows ValueHandlers and custom metadata to adjust itself. 870 if (!CS.getInstruction()->getType()->isVoidTy()) 871 ReplaceInstUsesWith(*CS.getInstruction(), 872 UndefValue::get(CS.getInstruction()->getType())); 873 874 if (InvokeInst *II = dyn_cast<InvokeInst>(CS.getInstruction())) { 875 // Don't break the CFG, insert a dummy cond branch. 876 BranchInst::Create(II->getNormalDest(), II->getUnwindDest(), 877 ConstantInt::getTrue(Callee->getContext()), II); 878 } 879 return EraseInstFromFunction(*CS.getInstruction()); 880 } 881 882 if (BitCastInst *BC = dyn_cast<BitCastInst>(Callee)) 883 if (IntrinsicInst *In = dyn_cast<IntrinsicInst>(BC->getOperand(0))) 884 if (In->getIntrinsicID() == Intrinsic::init_trampoline) 885 return transformCallThroughTrampoline(CS); 886 887 const PointerType *PTy = cast<PointerType>(Callee->getType()); 888 const FunctionType *FTy = cast<FunctionType>(PTy->getElementType()); 889 if (FTy->isVarArg()) { 890 int ix = FTy->getNumParams() + (isa<InvokeInst>(Callee) ? 3 : 1); 891 // See if we can optimize any arguments passed through the varargs area of 892 // the call. 893 for (CallSite::arg_iterator I = CS.arg_begin()+FTy->getNumParams(), 894 E = CS.arg_end(); I != E; ++I, ++ix) { 895 CastInst *CI = dyn_cast<CastInst>(*I); 896 if (CI && isSafeToEliminateVarargsCast(CS, CI, TD, ix)) { 897 *I = CI->getOperand(0); 898 Changed = true; 899 } 900 } 901 } 902 903 if (isa<InlineAsm>(Callee) && !CS.doesNotThrow()) { 904 // Inline asm calls cannot throw - mark them 'nounwind'. 905 CS.setDoesNotThrow(); 906 Changed = true; 907 } 908 909 // Try to optimize the call if possible, we require TargetData for most of 910 // this. None of these calls are seen as possibly dead so go ahead and 911 // delete the instruction now. 912 if (CallInst *CI = dyn_cast<CallInst>(CS.getInstruction())) { 913 Instruction *I = tryOptimizeCall(CI, TD); 914 // If we changed something return the result, etc. Otherwise let 915 // the fallthrough check. 916 if (I) return EraseInstFromFunction(*I); 917 } 918 919 return Changed ? CS.getInstruction() : 0; 920} 921 922// transformConstExprCastCall - If the callee is a constexpr cast of a function, 923// attempt to move the cast to the arguments of the call/invoke. 924// 925bool InstCombiner::transformConstExprCastCall(CallSite CS) { 926 Function *Callee = 927 dyn_cast<Function>(CS.getCalledValue()->stripPointerCasts()); 928 if (Callee == 0) 929 return false; 930 Instruction *Caller = CS.getInstruction(); 931 const AttrListPtr &CallerPAL = CS.getAttributes(); 932 933 // Okay, this is a cast from a function to a different type. Unless doing so 934 // would cause a type conversion of one of our arguments, change this call to 935 // be a direct call with arguments casted to the appropriate types. 936 // 937 const FunctionType *FT = Callee->getFunctionType(); 938 const Type *OldRetTy = Caller->getType(); 939 const Type *NewRetTy = FT->getReturnType(); 940 941 if (NewRetTy->isStructTy()) 942 return false; // TODO: Handle multiple return values. 943 944 // Check to see if we are changing the return type... 945 if (OldRetTy != NewRetTy) { 946 if (Callee->isDeclaration() && 947 // Conversion is ok if changing from one pointer type to another or from 948 // a pointer to an integer of the same size. 949 !((OldRetTy->isPointerTy() || !TD || 950 OldRetTy == TD->getIntPtrType(Caller->getContext())) && 951 (NewRetTy->isPointerTy() || !TD || 952 NewRetTy == TD->getIntPtrType(Caller->getContext())))) 953 return false; // Cannot transform this return value. 954 955 if (!Caller->use_empty() && 956 // void -> non-void is handled specially 957 !NewRetTy->isVoidTy() && !CastInst::isCastable(NewRetTy, OldRetTy)) 958 return false; // Cannot transform this return value. 959 960 if (!CallerPAL.isEmpty() && !Caller->use_empty()) { 961 Attributes RAttrs = CallerPAL.getRetAttributes(); 962 if (RAttrs & Attribute::typeIncompatible(NewRetTy)) 963 return false; // Attribute not compatible with transformed value. 964 } 965 966 // If the callsite is an invoke instruction, and the return value is used by 967 // a PHI node in a successor, we cannot change the return type of the call 968 // because there is no place to put the cast instruction (without breaking 969 // the critical edge). Bail out in this case. 970 if (!Caller->use_empty()) 971 if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) 972 for (Value::use_iterator UI = II->use_begin(), E = II->use_end(); 973 UI != E; ++UI) 974 if (PHINode *PN = dyn_cast<PHINode>(*UI)) 975 if (PN->getParent() == II->getNormalDest() || 976 PN->getParent() == II->getUnwindDest()) 977 return false; 978 } 979 980 unsigned NumActualArgs = unsigned(CS.arg_end()-CS.arg_begin()); 981 unsigned NumCommonArgs = std::min(FT->getNumParams(), NumActualArgs); 982 983 CallSite::arg_iterator AI = CS.arg_begin(); 984 for (unsigned i = 0, e = NumCommonArgs; i != e; ++i, ++AI) { 985 const Type *ParamTy = FT->getParamType(i); 986 const Type *ActTy = (*AI)->getType(); 987 988 if (!CastInst::isCastable(ActTy, ParamTy)) 989 return false; // Cannot transform this parameter value. 990 991 unsigned Attrs = CallerPAL.getParamAttributes(i + 1); 992 if (Attrs & Attribute::typeIncompatible(ParamTy)) 993 return false; // Attribute not compatible with transformed value. 994 995 // If the parameter is passed as a byval argument, then we have to have a 996 // sized type and the sized type has to have the same size as the old type. 997 if (ParamTy != ActTy && (Attrs & Attribute::ByVal)) { 998 const PointerType *ParamPTy = dyn_cast<PointerType>(ParamTy); 999 if (ParamPTy == 0 || !ParamPTy->getElementType()->isSized() || TD == 0) 1000 return false; 1001 1002 const Type *CurElTy = cast<PointerType>(ActTy)->getElementType(); 1003 if (TD->getTypeAllocSize(CurElTy) != 1004 TD->getTypeAllocSize(ParamPTy->getElementType())) 1005 return false; 1006 } 1007 1008 // Converting from one pointer type to another or between a pointer and an 1009 // integer of the same size is safe even if we do not have a body. 1010 bool isConvertible = ActTy == ParamTy || 1011 (TD && ((ParamTy->isPointerTy() || 1012 ParamTy == TD->getIntPtrType(Caller->getContext())) && 1013 (ActTy->isPointerTy() || 1014 ActTy == TD->getIntPtrType(Caller->getContext())))); 1015 if (Callee->isDeclaration() && !isConvertible) return false; 1016 } 1017 1018 if (Callee->isDeclaration()) { 1019 // Do not delete arguments unless we have a function body. 1020 if (FT->getNumParams() < NumActualArgs && !FT->isVarArg()) 1021 return false; 1022 1023 // If the callee is just a declaration, don't change the varargsness of the 1024 // call. We don't want to introduce a varargs call where one doesn't 1025 // already exist. 1026 const PointerType *APTy = cast<PointerType>(CS.getCalledValue()->getType()); 1027 if (FT->isVarArg()!=cast<FunctionType>(APTy->getElementType())->isVarArg()) 1028 return false; 1029 } 1030 1031 if (FT->getNumParams() < NumActualArgs && FT->isVarArg() && 1032 !CallerPAL.isEmpty()) 1033 // In this case we have more arguments than the new function type, but we 1034 // won't be dropping them. Check that these extra arguments have attributes 1035 // that are compatible with being a vararg call argument. 1036 for (unsigned i = CallerPAL.getNumSlots(); i; --i) { 1037 if (CallerPAL.getSlot(i - 1).Index <= FT->getNumParams()) 1038 break; 1039 Attributes PAttrs = CallerPAL.getSlot(i - 1).Attrs; 1040 if (PAttrs & Attribute::VarArgsIncompatible) 1041 return false; 1042 } 1043 1044 1045 // Okay, we decided that this is a safe thing to do: go ahead and start 1046 // inserting cast instructions as necessary. 1047 std::vector<Value*> Args; 1048 Args.reserve(NumActualArgs); 1049 SmallVector<AttributeWithIndex, 8> attrVec; 1050 attrVec.reserve(NumCommonArgs); 1051 1052 // Get any return attributes. 1053 Attributes RAttrs = CallerPAL.getRetAttributes(); 1054 1055 // If the return value is not being used, the type may not be compatible 1056 // with the existing attributes. Wipe out any problematic attributes. 1057 RAttrs &= ~Attribute::typeIncompatible(NewRetTy); 1058 1059 // Add the new return attributes. 1060 if (RAttrs) 1061 attrVec.push_back(AttributeWithIndex::get(0, RAttrs)); 1062 1063 AI = CS.arg_begin(); 1064 for (unsigned i = 0; i != NumCommonArgs; ++i, ++AI) { 1065 const Type *ParamTy = FT->getParamType(i); 1066 if ((*AI)->getType() == ParamTy) { 1067 Args.push_back(*AI); 1068 } else { 1069 Instruction::CastOps opcode = CastInst::getCastOpcode(*AI, 1070 false, ParamTy, false); 1071 Args.push_back(Builder->CreateCast(opcode, *AI, ParamTy, "tmp")); 1072 } 1073 1074 // Add any parameter attributes. 1075 if (Attributes PAttrs = CallerPAL.getParamAttributes(i + 1)) 1076 attrVec.push_back(AttributeWithIndex::get(i + 1, PAttrs)); 1077 } 1078 1079 // If the function takes more arguments than the call was taking, add them 1080 // now. 1081 for (unsigned i = NumCommonArgs; i != FT->getNumParams(); ++i) 1082 Args.push_back(Constant::getNullValue(FT->getParamType(i))); 1083 1084 // If we are removing arguments to the function, emit an obnoxious warning. 1085 if (FT->getNumParams() < NumActualArgs) { 1086 if (!FT->isVarArg()) { 1087 errs() << "WARNING: While resolving call to function '" 1088 << Callee->getName() << "' arguments were dropped!\n"; 1089 } else { 1090 // Add all of the arguments in their promoted form to the arg list. 1091 for (unsigned i = FT->getNumParams(); i != NumActualArgs; ++i, ++AI) { 1092 const Type *PTy = getPromotedType((*AI)->getType()); 1093 if (PTy != (*AI)->getType()) { 1094 // Must promote to pass through va_arg area! 1095 Instruction::CastOps opcode = 1096 CastInst::getCastOpcode(*AI, false, PTy, false); 1097 Args.push_back(Builder->CreateCast(opcode, *AI, PTy, "tmp")); 1098 } else { 1099 Args.push_back(*AI); 1100 } 1101 1102 // Add any parameter attributes. 1103 if (Attributes PAttrs = CallerPAL.getParamAttributes(i + 1)) 1104 attrVec.push_back(AttributeWithIndex::get(i + 1, PAttrs)); 1105 } 1106 } 1107 } 1108 1109 if (Attributes FnAttrs = CallerPAL.getFnAttributes()) 1110 attrVec.push_back(AttributeWithIndex::get(~0, FnAttrs)); 1111 1112 if (NewRetTy->isVoidTy()) 1113 Caller->setName(""); // Void type should not have a name. 1114 1115 const AttrListPtr &NewCallerPAL = AttrListPtr::get(attrVec.begin(), 1116 attrVec.end()); 1117 1118 Instruction *NC; 1119 if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) { 1120 NC = Builder->CreateInvoke(Callee, II->getNormalDest(), 1121 II->getUnwindDest(), Args.begin(), Args.end()); 1122 NC->takeName(II); 1123 cast<InvokeInst>(NC)->setCallingConv(II->getCallingConv()); 1124 cast<InvokeInst>(NC)->setAttributes(NewCallerPAL); 1125 } else { 1126 CallInst *CI = cast<CallInst>(Caller); 1127 NC = Builder->CreateCall(Callee, Args.begin(), Args.end()); 1128 NC->takeName(CI); 1129 if (CI->isTailCall()) 1130 cast<CallInst>(NC)->setTailCall(); 1131 cast<CallInst>(NC)->setCallingConv(CI->getCallingConv()); 1132 cast<CallInst>(NC)->setAttributes(NewCallerPAL); 1133 } 1134 1135 // Insert a cast of the return type as necessary. 1136 Value *NV = NC; 1137 if (OldRetTy != NV->getType() && !Caller->use_empty()) { 1138 if (!NV->getType()->isVoidTy()) { 1139 Instruction::CastOps opcode = 1140 CastInst::getCastOpcode(NC, false, OldRetTy, false); 1141 NV = NC = CastInst::Create(opcode, NC, OldRetTy, "tmp"); 1142 NC->setDebugLoc(Caller->getDebugLoc()); 1143 1144 // If this is an invoke instruction, we should insert it after the first 1145 // non-phi, instruction in the normal successor block. 1146 if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) { 1147 BasicBlock::iterator I = II->getNormalDest()->getFirstNonPHI(); 1148 InsertNewInstBefore(NC, *I); 1149 } else { 1150 // Otherwise, it's a call, just insert cast right after the call. 1151 InsertNewInstBefore(NC, *Caller); 1152 } 1153 Worklist.AddUsersToWorkList(*Caller); 1154 } else { 1155 NV = UndefValue::get(Caller->getType()); 1156 } 1157 } 1158 1159 if (!Caller->use_empty()) 1160 ReplaceInstUsesWith(*Caller, NV); 1161 1162 EraseInstFromFunction(*Caller); 1163 return true; 1164} 1165 1166// transformCallThroughTrampoline - Turn a call to a function created by the 1167// init_trampoline intrinsic into a direct call to the underlying function. 1168// 1169Instruction *InstCombiner::transformCallThroughTrampoline(CallSite CS) { 1170 Value *Callee = CS.getCalledValue(); 1171 const PointerType *PTy = cast<PointerType>(Callee->getType()); 1172 const FunctionType *FTy = cast<FunctionType>(PTy->getElementType()); 1173 const AttrListPtr &Attrs = CS.getAttributes(); 1174 1175 // If the call already has the 'nest' attribute somewhere then give up - 1176 // otherwise 'nest' would occur twice after splicing in the chain. 1177 if (Attrs.hasAttrSomewhere(Attribute::Nest)) 1178 return 0; 1179 1180 IntrinsicInst *Tramp = 1181 cast<IntrinsicInst>(cast<BitCastInst>(Callee)->getOperand(0)); 1182 1183 Function *NestF =cast<Function>(Tramp->getArgOperand(1)->stripPointerCasts()); 1184 const PointerType *NestFPTy = cast<PointerType>(NestF->getType()); 1185 const FunctionType *NestFTy = cast<FunctionType>(NestFPTy->getElementType()); 1186 1187 const AttrListPtr &NestAttrs = NestF->getAttributes(); 1188 if (!NestAttrs.isEmpty()) { 1189 unsigned NestIdx = 1; 1190 const Type *NestTy = 0; 1191 Attributes NestAttr = Attribute::None; 1192 1193 // Look for a parameter marked with the 'nest' attribute. 1194 for (FunctionType::param_iterator I = NestFTy->param_begin(), 1195 E = NestFTy->param_end(); I != E; ++NestIdx, ++I) 1196 if (NestAttrs.paramHasAttr(NestIdx, Attribute::Nest)) { 1197 // Record the parameter type and any other attributes. 1198 NestTy = *I; 1199 NestAttr = NestAttrs.getParamAttributes(NestIdx); 1200 break; 1201 } 1202 1203 if (NestTy) { 1204 Instruction *Caller = CS.getInstruction(); 1205 std::vector<Value*> NewArgs; 1206 NewArgs.reserve(unsigned(CS.arg_end()-CS.arg_begin())+1); 1207 1208 SmallVector<AttributeWithIndex, 8> NewAttrs; 1209 NewAttrs.reserve(Attrs.getNumSlots() + 1); 1210 1211 // Insert the nest argument into the call argument list, which may 1212 // mean appending it. Likewise for attributes. 1213 1214 // Add any result attributes. 1215 if (Attributes Attr = Attrs.getRetAttributes()) 1216 NewAttrs.push_back(AttributeWithIndex::get(0, Attr)); 1217 1218 { 1219 unsigned Idx = 1; 1220 CallSite::arg_iterator I = CS.arg_begin(), E = CS.arg_end(); 1221 do { 1222 if (Idx == NestIdx) { 1223 // Add the chain argument and attributes. 1224 Value *NestVal = Tramp->getArgOperand(2); 1225 if (NestVal->getType() != NestTy) 1226 NestVal = Builder->CreateBitCast(NestVal, NestTy, "nest"); 1227 NewArgs.push_back(NestVal); 1228 NewAttrs.push_back(AttributeWithIndex::get(NestIdx, NestAttr)); 1229 } 1230 1231 if (I == E) 1232 break; 1233 1234 // Add the original argument and attributes. 1235 NewArgs.push_back(*I); 1236 if (Attributes Attr = Attrs.getParamAttributes(Idx)) 1237 NewAttrs.push_back 1238 (AttributeWithIndex::get(Idx + (Idx >= NestIdx), Attr)); 1239 1240 ++Idx, ++I; 1241 } while (1); 1242 } 1243 1244 // Add any function attributes. 1245 if (Attributes Attr = Attrs.getFnAttributes()) 1246 NewAttrs.push_back(AttributeWithIndex::get(~0, Attr)); 1247 1248 // The trampoline may have been bitcast to a bogus type (FTy). 1249 // Handle this by synthesizing a new function type, equal to FTy 1250 // with the chain parameter inserted. 1251 1252 std::vector<const Type*> NewTypes; 1253 NewTypes.reserve(FTy->getNumParams()+1); 1254 1255 // Insert the chain's type into the list of parameter types, which may 1256 // mean appending it. 1257 { 1258 unsigned Idx = 1; 1259 FunctionType::param_iterator I = FTy->param_begin(), 1260 E = FTy->param_end(); 1261 1262 do { 1263 if (Idx == NestIdx) 1264 // Add the chain's type. 1265 NewTypes.push_back(NestTy); 1266 1267 if (I == E) 1268 break; 1269 1270 // Add the original type. 1271 NewTypes.push_back(*I); 1272 1273 ++Idx, ++I; 1274 } while (1); 1275 } 1276 1277 // Replace the trampoline call with a direct call. Let the generic 1278 // code sort out any function type mismatches. 1279 FunctionType *NewFTy = FunctionType::get(FTy->getReturnType(), NewTypes, 1280 FTy->isVarArg()); 1281 Constant *NewCallee = 1282 NestF->getType() == PointerType::getUnqual(NewFTy) ? 1283 NestF : ConstantExpr::getBitCast(NestF, 1284 PointerType::getUnqual(NewFTy)); 1285 const AttrListPtr &NewPAL = AttrListPtr::get(NewAttrs.begin(), 1286 NewAttrs.end()); 1287 1288 Instruction *NewCaller; 1289 if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) { 1290 NewCaller = InvokeInst::Create(NewCallee, 1291 II->getNormalDest(), II->getUnwindDest(), 1292 NewArgs.begin(), NewArgs.end()); 1293 cast<InvokeInst>(NewCaller)->setCallingConv(II->getCallingConv()); 1294 cast<InvokeInst>(NewCaller)->setAttributes(NewPAL); 1295 } else { 1296 NewCaller = CallInst::Create(NewCallee, NewArgs.begin(), NewArgs.end()); 1297 if (cast<CallInst>(Caller)->isTailCall()) 1298 cast<CallInst>(NewCaller)->setTailCall(); 1299 cast<CallInst>(NewCaller)-> 1300 setCallingConv(cast<CallInst>(Caller)->getCallingConv()); 1301 cast<CallInst>(NewCaller)->setAttributes(NewPAL); 1302 } 1303 1304 return NewCaller; 1305 } 1306 } 1307 1308 // Replace the trampoline call with a direct call. Since there is no 'nest' 1309 // parameter, there is no need to adjust the argument list. Let the generic 1310 // code sort out any function type mismatches. 1311 Constant *NewCallee = 1312 NestF->getType() == PTy ? NestF : 1313 ConstantExpr::getBitCast(NestF, PTy); 1314 CS.setCalledFunction(NewCallee); 1315 return CS.getInstruction(); 1316} 1317 1318