InstCombineCalls.cpp revision c21b205f93fa7bc135928ff9f4981f9062e2fd53
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 = cast<IntegerType>(II->getArgOperand(0)->getType()); 359 uint32_t BitWidth = IT->getBitWidth(); 360 APInt KnownZero(BitWidth, 0); 361 APInt KnownOne(BitWidth, 0); 362 ComputeMaskedBits(II->getArgOperand(0), APInt::getAllOnesValue(BitWidth), 363 KnownZero, KnownOne); 364 unsigned TrailingZeros = KnownOne.countTrailingZeros(); 365 APInt Mask(APInt::getLowBitsSet(BitWidth, TrailingZeros)); 366 if ((Mask & KnownZero) == Mask) 367 return ReplaceInstUsesWith(CI, ConstantInt::get(IT, 368 APInt(BitWidth, TrailingZeros))); 369 370 } 371 break; 372 case Intrinsic::ctlz: { 373 // If all bits above the first known one are known zero, 374 // this value is constant. 375 const IntegerType *IT = cast<IntegerType>(II->getArgOperand(0)->getType()); 376 uint32_t BitWidth = IT->getBitWidth(); 377 APInt KnownZero(BitWidth, 0); 378 APInt KnownOne(BitWidth, 0); 379 ComputeMaskedBits(II->getArgOperand(0), APInt::getAllOnesValue(BitWidth), 380 KnownZero, KnownOne); 381 unsigned LeadingZeros = KnownOne.countLeadingZeros(); 382 APInt Mask(APInt::getHighBitsSet(BitWidth, LeadingZeros)); 383 if ((Mask & KnownZero) == Mask) 384 return ReplaceInstUsesWith(CI, ConstantInt::get(IT, 385 APInt(BitWidth, LeadingZeros))); 386 387 } 388 break; 389 case Intrinsic::uadd_with_overflow: { 390 Value *LHS = II->getArgOperand(0), *RHS = II->getArgOperand(1); 391 const IntegerType *IT = cast<IntegerType>(II->getArgOperand(0)->getType()); 392 uint32_t BitWidth = IT->getBitWidth(); 393 APInt Mask = APInt::getSignBit(BitWidth); 394 APInt LHSKnownZero(BitWidth, 0); 395 APInt LHSKnownOne(BitWidth, 0); 396 ComputeMaskedBits(LHS, Mask, LHSKnownZero, LHSKnownOne); 397 bool LHSKnownNegative = LHSKnownOne[BitWidth - 1]; 398 bool LHSKnownPositive = LHSKnownZero[BitWidth - 1]; 399 400 if (LHSKnownNegative || LHSKnownPositive) { 401 APInt RHSKnownZero(BitWidth, 0); 402 APInt RHSKnownOne(BitWidth, 0); 403 ComputeMaskedBits(RHS, Mask, RHSKnownZero, RHSKnownOne); 404 bool RHSKnownNegative = RHSKnownOne[BitWidth - 1]; 405 bool RHSKnownPositive = RHSKnownZero[BitWidth - 1]; 406 if (LHSKnownNegative && RHSKnownNegative) { 407 // The sign bit is set in both cases: this MUST overflow. 408 // Create a simple add instruction, and insert it into the struct. 409 Value *Add = Builder->CreateAdd(LHS, RHS); 410 Add->takeName(&CI); 411 Constant *V[] = { 412 UndefValue::get(LHS->getType()), 413 ConstantInt::getTrue(II->getContext()) 414 }; 415 Constant *Struct = ConstantStruct::get(II->getContext(), V, 2, false); 416 return InsertValueInst::Create(Struct, Add, 0); 417 } 418 419 if (LHSKnownPositive && RHSKnownPositive) { 420 // The sign bit is clear in both cases: this CANNOT overflow. 421 // Create a simple add instruction, and insert it into the struct. 422 Value *Add = Builder->CreateNUWAdd(LHS, RHS); 423 Add->takeName(&CI); 424 Constant *V[] = { 425 UndefValue::get(LHS->getType()), 426 ConstantInt::getFalse(II->getContext()) 427 }; 428 Constant *Struct = ConstantStruct::get(II->getContext(), V, 2, false); 429 return InsertValueInst::Create(Struct, Add, 0); 430 } 431 } 432 } 433 // FALL THROUGH uadd into sadd 434 case Intrinsic::sadd_with_overflow: 435 // Canonicalize constants into the RHS. 436 if (isa<Constant>(II->getArgOperand(0)) && 437 !isa<Constant>(II->getArgOperand(1))) { 438 Value *LHS = II->getArgOperand(0); 439 II->setArgOperand(0, II->getArgOperand(1)); 440 II->setArgOperand(1, LHS); 441 return II; 442 } 443 444 // X + undef -> undef 445 if (isa<UndefValue>(II->getArgOperand(1))) 446 return ReplaceInstUsesWith(CI, UndefValue::get(II->getType())); 447 448 if (ConstantInt *RHS = dyn_cast<ConstantInt>(II->getArgOperand(1))) { 449 // X + 0 -> {X, false} 450 if (RHS->isZero()) { 451 Constant *V[] = { 452 UndefValue::get(II->getArgOperand(0)->getType()), 453 ConstantInt::getFalse(II->getContext()) 454 }; 455 Constant *Struct = ConstantStruct::get(II->getContext(), V, 2, false); 456 return InsertValueInst::Create(Struct, II->getArgOperand(0), 0); 457 } 458 } 459 break; 460 case Intrinsic::usub_with_overflow: 461 case Intrinsic::ssub_with_overflow: 462 // undef - X -> undef 463 // X - undef -> undef 464 if (isa<UndefValue>(II->getArgOperand(0)) || 465 isa<UndefValue>(II->getArgOperand(1))) 466 return ReplaceInstUsesWith(CI, UndefValue::get(II->getType())); 467 468 if (ConstantInt *RHS = dyn_cast<ConstantInt>(II->getArgOperand(1))) { 469 // X - 0 -> {X, false} 470 if (RHS->isZero()) { 471 Constant *V[] = { 472 UndefValue::get(II->getArgOperand(0)->getType()), 473 ConstantInt::getFalse(II->getContext()) 474 }; 475 Constant *Struct = ConstantStruct::get(II->getContext(), V, 2, false); 476 return InsertValueInst::Create(Struct, II->getArgOperand(0), 0); 477 } 478 } 479 break; 480 case Intrinsic::umul_with_overflow: { 481 Value *LHS = II->getArgOperand(0), *RHS = II->getArgOperand(1); 482 unsigned BitWidth = cast<IntegerType>(LHS->getType())->getBitWidth(); 483 APInt Mask = APInt::getAllOnesValue(BitWidth); 484 485 APInt LHSKnownZero(BitWidth, 0); 486 APInt LHSKnownOne(BitWidth, 0); 487 ComputeMaskedBits(LHS, Mask, LHSKnownZero, LHSKnownOne); 488 APInt RHSKnownZero(BitWidth, 0); 489 APInt RHSKnownOne(BitWidth, 0); 490 ComputeMaskedBits(RHS, Mask, RHSKnownZero, RHSKnownOne); 491 492 // Get the largest possible values for each operand. 493 APInt LHSMax = ~LHSKnownZero; 494 APInt RHSMax = ~RHSKnownZero; 495 496 // If multiplying the maximum values does not overflow then we can turn 497 // this into a plain NUW mul. 498 bool Overflow; 499 LHSMax.umul_ov(RHSMax, Overflow); 500 if (!Overflow) { 501 Value *Mul = Builder->CreateNUWMul(LHS, RHS, "umul_with_overflow"); 502 Constant *V[] = { 503 UndefValue::get(LHS->getType()), 504 Builder->getFalse() 505 }; 506 Constant *Struct = ConstantStruct::get(II->getContext(), V, 2, false); 507 return InsertValueInst::Create(Struct, Mul, 0); 508 } 509 } // FALL THROUGH 510 case Intrinsic::smul_with_overflow: 511 // Canonicalize constants into the RHS. 512 if (isa<Constant>(II->getArgOperand(0)) && 513 !isa<Constant>(II->getArgOperand(1))) { 514 Value *LHS = II->getArgOperand(0); 515 II->setArgOperand(0, II->getArgOperand(1)); 516 II->setArgOperand(1, LHS); 517 return II; 518 } 519 520 // X * undef -> undef 521 if (isa<UndefValue>(II->getArgOperand(1))) 522 return ReplaceInstUsesWith(CI, UndefValue::get(II->getType())); 523 524 if (ConstantInt *RHSI = dyn_cast<ConstantInt>(II->getArgOperand(1))) { 525 // X*0 -> {0, false} 526 if (RHSI->isZero()) 527 return ReplaceInstUsesWith(CI, Constant::getNullValue(II->getType())); 528 529 // X * 1 -> {X, false} 530 if (RHSI->equalsInt(1)) { 531 Constant *V[] = { 532 UndefValue::get(II->getArgOperand(0)->getType()), 533 ConstantInt::getFalse(II->getContext()) 534 }; 535 Constant *Struct = ConstantStruct::get(II->getContext(), V, 2, false); 536 return InsertValueInst::Create(Struct, II->getArgOperand(0), 0); 537 } 538 539 // [su]mul.with.overflow(X, 2) -> [su]add.with.overflow(X, X) 540 if (RHSI->equalsInt(2)) { 541 Intrinsic::ID Add = 542 II->getIntrinsicID() == Intrinsic::smul_with_overflow ? 543 Intrinsic::sadd_with_overflow : Intrinsic::uadd_with_overflow; 544 545 Module *M = II->getParent()->getParent()->getParent(); 546 const Type *Ty = RHSI->getType(); 547 Function *F = Intrinsic::getDeclaration(M, Add, &Ty, 1); 548 549 Value *Ops[] = { II->getArgOperand(0), II->getArgOperand(0) }; 550 return CallInst::Create(F, Ops, Ops+2); 551 } 552 } 553 break; 554 case Intrinsic::ppc_altivec_lvx: 555 case Intrinsic::ppc_altivec_lvxl: 556 // Turn PPC lvx -> load if the pointer is known aligned. 557 if (getOrEnforceKnownAlignment(II->getArgOperand(0), 16, TD) >= 16) { 558 Value *Ptr = Builder->CreateBitCast(II->getArgOperand(0), 559 PointerType::getUnqual(II->getType())); 560 return new LoadInst(Ptr); 561 } 562 break; 563 case Intrinsic::ppc_altivec_stvx: 564 case Intrinsic::ppc_altivec_stvxl: 565 // Turn stvx -> store if the pointer is known aligned. 566 if (getOrEnforceKnownAlignment(II->getArgOperand(1), 16, TD) >= 16) { 567 const Type *OpPtrTy = 568 PointerType::getUnqual(II->getArgOperand(0)->getType()); 569 Value *Ptr = Builder->CreateBitCast(II->getArgOperand(1), OpPtrTy); 570 return new StoreInst(II->getArgOperand(0), Ptr); 571 } 572 break; 573 case Intrinsic::x86_sse_storeu_ps: 574 case Intrinsic::x86_sse2_storeu_pd: 575 case Intrinsic::x86_sse2_storeu_dq: 576 // Turn X86 storeu -> store if the pointer is known aligned. 577 if (getOrEnforceKnownAlignment(II->getArgOperand(0), 16, TD) >= 16) { 578 const Type *OpPtrTy = 579 PointerType::getUnqual(II->getArgOperand(1)->getType()); 580 Value *Ptr = Builder->CreateBitCast(II->getArgOperand(0), OpPtrTy); 581 return new StoreInst(II->getArgOperand(1), Ptr); 582 } 583 break; 584 585 case Intrinsic::x86_sse_cvtss2si: 586 case Intrinsic::x86_sse_cvtss2si64: 587 case Intrinsic::x86_sse_cvttss2si: 588 case Intrinsic::x86_sse_cvttss2si64: 589 case Intrinsic::x86_sse2_cvtsd2si: 590 case Intrinsic::x86_sse2_cvtsd2si64: 591 case Intrinsic::x86_sse2_cvttsd2si: 592 case Intrinsic::x86_sse2_cvttsd2si64: { 593 // These intrinsics only demand the 0th element of their input vectors. If 594 // we can simplify the input based on that, do so now. 595 unsigned VWidth = 596 cast<VectorType>(II->getArgOperand(0)->getType())->getNumElements(); 597 APInt DemandedElts(VWidth, 1); 598 APInt UndefElts(VWidth, 0); 599 if (Value *V = SimplifyDemandedVectorElts(II->getArgOperand(0), 600 DemandedElts, UndefElts)) { 601 II->setArgOperand(0, V); 602 return II; 603 } 604 break; 605 } 606 607 608 case Intrinsic::x86_sse41_pmovsxbw: 609 case Intrinsic::x86_sse41_pmovsxwd: 610 case Intrinsic::x86_sse41_pmovsxdq: 611 case Intrinsic::x86_sse41_pmovzxbw: 612 case Intrinsic::x86_sse41_pmovzxwd: 613 case Intrinsic::x86_sse41_pmovzxdq: { 614 // pmov{s|z}x ignores the upper half of their input vectors. 615 unsigned VWidth = 616 cast<VectorType>(II->getArgOperand(0)->getType())->getNumElements(); 617 unsigned LowHalfElts = VWidth / 2; 618 APInt InputDemandedElts(APInt::getBitsSet(VWidth, 0, LowHalfElts)); 619 APInt UndefElts(VWidth, 0); 620 if (Value *TmpV = SimplifyDemandedVectorElts(II->getArgOperand(0), 621 InputDemandedElts, 622 UndefElts)) { 623 II->setArgOperand(0, TmpV); 624 return II; 625 } 626 break; 627 } 628 629 case Intrinsic::ppc_altivec_vperm: 630 // Turn vperm(V1,V2,mask) -> shuffle(V1,V2,mask) if mask is a constant. 631 if (ConstantVector *Mask = dyn_cast<ConstantVector>(II->getArgOperand(2))) { 632 assert(Mask->getNumOperands() == 16 && "Bad type for intrinsic!"); 633 634 // Check that all of the elements are integer constants or undefs. 635 bool AllEltsOk = true; 636 for (unsigned i = 0; i != 16; ++i) { 637 if (!isa<ConstantInt>(Mask->getOperand(i)) && 638 !isa<UndefValue>(Mask->getOperand(i))) { 639 AllEltsOk = false; 640 break; 641 } 642 } 643 644 if (AllEltsOk) { 645 // Cast the input vectors to byte vectors. 646 Value *Op0 = Builder->CreateBitCast(II->getArgOperand(0), 647 Mask->getType()); 648 Value *Op1 = Builder->CreateBitCast(II->getArgOperand(1), 649 Mask->getType()); 650 Value *Result = UndefValue::get(Op0->getType()); 651 652 // Only extract each element once. 653 Value *ExtractedElts[32]; 654 memset(ExtractedElts, 0, sizeof(ExtractedElts)); 655 656 for (unsigned i = 0; i != 16; ++i) { 657 if (isa<UndefValue>(Mask->getOperand(i))) 658 continue; 659 unsigned Idx=cast<ConstantInt>(Mask->getOperand(i))->getZExtValue(); 660 Idx &= 31; // Match the hardware behavior. 661 662 if (ExtractedElts[Idx] == 0) { 663 ExtractedElts[Idx] = 664 Builder->CreateExtractElement(Idx < 16 ? Op0 : Op1, 665 ConstantInt::get(Type::getInt32Ty(II->getContext()), 666 Idx&15, false), "tmp"); 667 } 668 669 // Insert this value into the result vector. 670 Result = Builder->CreateInsertElement(Result, ExtractedElts[Idx], 671 ConstantInt::get(Type::getInt32Ty(II->getContext()), 672 i, false), "tmp"); 673 } 674 return CastInst::Create(Instruction::BitCast, Result, CI.getType()); 675 } 676 } 677 break; 678 679 case Intrinsic::arm_neon_vld1: 680 case Intrinsic::arm_neon_vld2: 681 case Intrinsic::arm_neon_vld3: 682 case Intrinsic::arm_neon_vld4: 683 case Intrinsic::arm_neon_vld2lane: 684 case Intrinsic::arm_neon_vld3lane: 685 case Intrinsic::arm_neon_vld4lane: 686 case Intrinsic::arm_neon_vst1: 687 case Intrinsic::arm_neon_vst2: 688 case Intrinsic::arm_neon_vst3: 689 case Intrinsic::arm_neon_vst4: 690 case Intrinsic::arm_neon_vst2lane: 691 case Intrinsic::arm_neon_vst3lane: 692 case Intrinsic::arm_neon_vst4lane: { 693 unsigned MemAlign = getKnownAlignment(II->getArgOperand(0), TD); 694 unsigned AlignArg = II->getNumArgOperands() - 1; 695 ConstantInt *IntrAlign = dyn_cast<ConstantInt>(II->getArgOperand(AlignArg)); 696 if (IntrAlign && IntrAlign->getZExtValue() < MemAlign) { 697 II->setArgOperand(AlignArg, 698 ConstantInt::get(Type::getInt32Ty(II->getContext()), 699 MemAlign, false)); 700 return II; 701 } 702 break; 703 } 704 705 case Intrinsic::stackrestore: { 706 // If the save is right next to the restore, remove the restore. This can 707 // happen when variable allocas are DCE'd. 708 if (IntrinsicInst *SS = dyn_cast<IntrinsicInst>(II->getArgOperand(0))) { 709 if (SS->getIntrinsicID() == Intrinsic::stacksave) { 710 BasicBlock::iterator BI = SS; 711 if (&*++BI == II) 712 return EraseInstFromFunction(CI); 713 } 714 } 715 716 // Scan down this block to see if there is another stack restore in the 717 // same block without an intervening call/alloca. 718 BasicBlock::iterator BI = II; 719 TerminatorInst *TI = II->getParent()->getTerminator(); 720 bool CannotRemove = false; 721 for (++BI; &*BI != TI; ++BI) { 722 if (isa<AllocaInst>(BI) || isMalloc(BI)) { 723 CannotRemove = true; 724 break; 725 } 726 if (CallInst *BCI = dyn_cast<CallInst>(BI)) { 727 if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(BCI)) { 728 // If there is a stackrestore below this one, remove this one. 729 if (II->getIntrinsicID() == Intrinsic::stackrestore) 730 return EraseInstFromFunction(CI); 731 // Otherwise, ignore the intrinsic. 732 } else { 733 // If we found a non-intrinsic call, we can't remove the stack 734 // restore. 735 CannotRemove = true; 736 break; 737 } 738 } 739 } 740 741 // If the stack restore is in a return/unwind block and if there are no 742 // allocas or calls between the restore and the return, nuke the restore. 743 if (!CannotRemove && (isa<ReturnInst>(TI) || isa<UnwindInst>(TI))) 744 return EraseInstFromFunction(CI); 745 break; 746 } 747 } 748 749 return visitCallSite(II); 750} 751 752// InvokeInst simplification 753// 754Instruction *InstCombiner::visitInvokeInst(InvokeInst &II) { 755 return visitCallSite(&II); 756} 757 758/// isSafeToEliminateVarargsCast - If this cast does not affect the value 759/// passed through the varargs area, we can eliminate the use of the cast. 760static bool isSafeToEliminateVarargsCast(const CallSite CS, 761 const CastInst * const CI, 762 const TargetData * const TD, 763 const int ix) { 764 if (!CI->isLosslessCast()) 765 return false; 766 767 // The size of ByVal arguments is derived from the type, so we 768 // can't change to a type with a different size. If the size were 769 // passed explicitly we could avoid this check. 770 if (!CS.paramHasAttr(ix, Attribute::ByVal)) 771 return true; 772 773 const Type* SrcTy = 774 cast<PointerType>(CI->getOperand(0)->getType())->getElementType(); 775 const Type* DstTy = cast<PointerType>(CI->getType())->getElementType(); 776 if (!SrcTy->isSized() || !DstTy->isSized()) 777 return false; 778 if (!TD || TD->getTypeAllocSize(SrcTy) != TD->getTypeAllocSize(DstTy)) 779 return false; 780 return true; 781} 782 783namespace { 784class InstCombineFortifiedLibCalls : public SimplifyFortifiedLibCalls { 785 InstCombiner *IC; 786protected: 787 void replaceCall(Value *With) { 788 NewInstruction = IC->ReplaceInstUsesWith(*CI, With); 789 } 790 bool isFoldable(unsigned SizeCIOp, unsigned SizeArgOp, bool isString) const { 791 if (CI->getArgOperand(SizeCIOp) == CI->getArgOperand(SizeArgOp)) 792 return true; 793 if (ConstantInt *SizeCI = 794 dyn_cast<ConstantInt>(CI->getArgOperand(SizeCIOp))) { 795 if (SizeCI->isAllOnesValue()) 796 return true; 797 if (isString) { 798 uint64_t Len = GetStringLength(CI->getArgOperand(SizeArgOp)); 799 // If the length is 0 we don't know how long it is and so we can't 800 // remove the check. 801 if (Len == 0) return false; 802 return SizeCI->getZExtValue() >= Len; 803 } 804 if (ConstantInt *Arg = dyn_cast<ConstantInt>( 805 CI->getArgOperand(SizeArgOp))) 806 return SizeCI->getZExtValue() >= Arg->getZExtValue(); 807 } 808 return false; 809 } 810public: 811 InstCombineFortifiedLibCalls(InstCombiner *IC) : IC(IC), NewInstruction(0) { } 812 Instruction *NewInstruction; 813}; 814} // end anonymous namespace 815 816// Try to fold some different type of calls here. 817// Currently we're only working with the checking functions, memcpy_chk, 818// mempcpy_chk, memmove_chk, memset_chk, strcpy_chk, stpcpy_chk, strncpy_chk, 819// strcat_chk and strncat_chk. 820Instruction *InstCombiner::tryOptimizeCall(CallInst *CI, const TargetData *TD) { 821 if (CI->getCalledFunction() == 0) return 0; 822 823 InstCombineFortifiedLibCalls Simplifier(this); 824 Simplifier.fold(CI, TD); 825 return Simplifier.NewInstruction; 826} 827 828// visitCallSite - Improvements for call and invoke instructions. 829// 830Instruction *InstCombiner::visitCallSite(CallSite CS) { 831 bool Changed = false; 832 833 // If the callee is a pointer to a function, attempt to move any casts to the 834 // arguments of the call/invoke. 835 Value *Callee = CS.getCalledValue(); 836 if (!isa<Function>(Callee) && transformConstExprCastCall(CS)) 837 return 0; 838 839 if (Function *CalleeF = dyn_cast<Function>(Callee)) 840 // If the call and callee calling conventions don't match, this call must 841 // be unreachable, as the call is undefined. 842 if (CalleeF->getCallingConv() != CS.getCallingConv() && 843 // Only do this for calls to a function with a body. A prototype may 844 // not actually end up matching the implementation's calling conv for a 845 // variety of reasons (e.g. it may be written in assembly). 846 !CalleeF->isDeclaration()) { 847 Instruction *OldCall = CS.getInstruction(); 848 new StoreInst(ConstantInt::getTrue(Callee->getContext()), 849 UndefValue::get(Type::getInt1PtrTy(Callee->getContext())), 850 OldCall); 851 // If OldCall dues not return void then replaceAllUsesWith undef. 852 // This allows ValueHandlers and custom metadata to adjust itself. 853 if (!OldCall->getType()->isVoidTy()) 854 ReplaceInstUsesWith(*OldCall, UndefValue::get(OldCall->getType())); 855 if (isa<CallInst>(OldCall)) 856 return EraseInstFromFunction(*OldCall); 857 858 // We cannot remove an invoke, because it would change the CFG, just 859 // change the callee to a null pointer. 860 cast<InvokeInst>(OldCall)->setCalledFunction( 861 Constant::getNullValue(CalleeF->getType())); 862 return 0; 863 } 864 865 if (isa<ConstantPointerNull>(Callee) || isa<UndefValue>(Callee)) { 866 // This instruction is not reachable, just remove it. We insert a store to 867 // undef so that we know that this code is not reachable, despite the fact 868 // that we can't modify the CFG here. 869 new StoreInst(ConstantInt::getTrue(Callee->getContext()), 870 UndefValue::get(Type::getInt1PtrTy(Callee->getContext())), 871 CS.getInstruction()); 872 873 // If CS does not return void then replaceAllUsesWith undef. 874 // This allows ValueHandlers and custom metadata to adjust itself. 875 if (!CS.getInstruction()->getType()->isVoidTy()) 876 ReplaceInstUsesWith(*CS.getInstruction(), 877 UndefValue::get(CS.getInstruction()->getType())); 878 879 if (InvokeInst *II = dyn_cast<InvokeInst>(CS.getInstruction())) { 880 // Don't break the CFG, insert a dummy cond branch. 881 BranchInst::Create(II->getNormalDest(), II->getUnwindDest(), 882 ConstantInt::getTrue(Callee->getContext()), II); 883 } 884 return EraseInstFromFunction(*CS.getInstruction()); 885 } 886 887 if (BitCastInst *BC = dyn_cast<BitCastInst>(Callee)) 888 if (IntrinsicInst *In = dyn_cast<IntrinsicInst>(BC->getOperand(0))) 889 if (In->getIntrinsicID() == Intrinsic::init_trampoline) 890 return transformCallThroughTrampoline(CS); 891 892 const PointerType *PTy = cast<PointerType>(Callee->getType()); 893 const FunctionType *FTy = cast<FunctionType>(PTy->getElementType()); 894 if (FTy->isVarArg()) { 895 int ix = FTy->getNumParams() + (isa<InvokeInst>(Callee) ? 3 : 1); 896 // See if we can optimize any arguments passed through the varargs area of 897 // the call. 898 for (CallSite::arg_iterator I = CS.arg_begin()+FTy->getNumParams(), 899 E = CS.arg_end(); I != E; ++I, ++ix) { 900 CastInst *CI = dyn_cast<CastInst>(*I); 901 if (CI && isSafeToEliminateVarargsCast(CS, CI, TD, ix)) { 902 *I = CI->getOperand(0); 903 Changed = true; 904 } 905 } 906 } 907 908 if (isa<InlineAsm>(Callee) && !CS.doesNotThrow()) { 909 // Inline asm calls cannot throw - mark them 'nounwind'. 910 CS.setDoesNotThrow(); 911 Changed = true; 912 } 913 914 // Try to optimize the call if possible, we require TargetData for most of 915 // this. None of these calls are seen as possibly dead so go ahead and 916 // delete the instruction now. 917 if (CallInst *CI = dyn_cast<CallInst>(CS.getInstruction())) { 918 Instruction *I = tryOptimizeCall(CI, TD); 919 // If we changed something return the result, etc. Otherwise let 920 // the fallthrough check. 921 if (I) return EraseInstFromFunction(*I); 922 } 923 924 return Changed ? CS.getInstruction() : 0; 925} 926 927// transformConstExprCastCall - If the callee is a constexpr cast of a function, 928// attempt to move the cast to the arguments of the call/invoke. 929// 930bool InstCombiner::transformConstExprCastCall(CallSite CS) { 931 Function *Callee = 932 dyn_cast<Function>(CS.getCalledValue()->stripPointerCasts()); 933 if (Callee == 0) 934 return false; 935 Instruction *Caller = CS.getInstruction(); 936 const AttrListPtr &CallerPAL = CS.getAttributes(); 937 938 // Okay, this is a cast from a function to a different type. Unless doing so 939 // would cause a type conversion of one of our arguments, change this call to 940 // be a direct call with arguments casted to the appropriate types. 941 // 942 const FunctionType *FT = Callee->getFunctionType(); 943 const Type *OldRetTy = Caller->getType(); 944 const Type *NewRetTy = FT->getReturnType(); 945 946 if (NewRetTy->isStructTy()) 947 return false; // TODO: Handle multiple return values. 948 949 // Check to see if we are changing the return type... 950 if (OldRetTy != NewRetTy) { 951 if (Callee->isDeclaration() && 952 // Conversion is ok if changing from one pointer type to another or from 953 // a pointer to an integer of the same size. 954 !((OldRetTy->isPointerTy() || !TD || 955 OldRetTy == TD->getIntPtrType(Caller->getContext())) && 956 (NewRetTy->isPointerTy() || !TD || 957 NewRetTy == TD->getIntPtrType(Caller->getContext())))) 958 return false; // Cannot transform this return value. 959 960 if (!Caller->use_empty() && 961 // void -> non-void is handled specially 962 !NewRetTy->isVoidTy() && !CastInst::isCastable(NewRetTy, OldRetTy)) 963 return false; // Cannot transform this return value. 964 965 if (!CallerPAL.isEmpty() && !Caller->use_empty()) { 966 Attributes RAttrs = CallerPAL.getRetAttributes(); 967 if (RAttrs & Attribute::typeIncompatible(NewRetTy)) 968 return false; // Attribute not compatible with transformed value. 969 } 970 971 // If the callsite is an invoke instruction, and the return value is used by 972 // a PHI node in a successor, we cannot change the return type of the call 973 // because there is no place to put the cast instruction (without breaking 974 // the critical edge). Bail out in this case. 975 if (!Caller->use_empty()) 976 if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) 977 for (Value::use_iterator UI = II->use_begin(), E = II->use_end(); 978 UI != E; ++UI) 979 if (PHINode *PN = dyn_cast<PHINode>(*UI)) 980 if (PN->getParent() == II->getNormalDest() || 981 PN->getParent() == II->getUnwindDest()) 982 return false; 983 } 984 985 unsigned NumActualArgs = unsigned(CS.arg_end()-CS.arg_begin()); 986 unsigned NumCommonArgs = std::min(FT->getNumParams(), NumActualArgs); 987 988 CallSite::arg_iterator AI = CS.arg_begin(); 989 for (unsigned i = 0, e = NumCommonArgs; i != e; ++i, ++AI) { 990 const Type *ParamTy = FT->getParamType(i); 991 const Type *ActTy = (*AI)->getType(); 992 993 if (!CastInst::isCastable(ActTy, ParamTy)) 994 return false; // Cannot transform this parameter value. 995 996 unsigned Attrs = CallerPAL.getParamAttributes(i + 1); 997 if (Attrs & Attribute::typeIncompatible(ParamTy)) 998 return false; // Attribute not compatible with transformed value. 999 1000 // If the parameter is passed as a byval argument, then we have to have a 1001 // sized type and the sized type has to have the same size as the old type. 1002 if (ParamTy != ActTy && (Attrs & Attribute::ByVal)) { 1003 const PointerType *ParamPTy = dyn_cast<PointerType>(ParamTy); 1004 if (ParamPTy == 0 || !ParamPTy->getElementType()->isSized() || TD == 0) 1005 return false; 1006 1007 const Type *CurElTy = cast<PointerType>(ActTy)->getElementType(); 1008 if (TD->getTypeAllocSize(CurElTy) != 1009 TD->getTypeAllocSize(ParamPTy->getElementType())) 1010 return false; 1011 } 1012 1013 // Converting from one pointer type to another or between a pointer and an 1014 // integer of the same size is safe even if we do not have a body. 1015 bool isConvertible = ActTy == ParamTy || 1016 (TD && ((ParamTy->isPointerTy() || 1017 ParamTy == TD->getIntPtrType(Caller->getContext())) && 1018 (ActTy->isPointerTy() || 1019 ActTy == TD->getIntPtrType(Caller->getContext())))); 1020 if (Callee->isDeclaration() && !isConvertible) return false; 1021 } 1022 1023 if (Callee->isDeclaration()) { 1024 // Do not delete arguments unless we have a function body. 1025 if (FT->getNumParams() < NumActualArgs && !FT->isVarArg()) 1026 return false; 1027 1028 // If the callee is just a declaration, don't change the varargsness of the 1029 // call. We don't want to introduce a varargs call where one doesn't 1030 // already exist. 1031 const PointerType *APTy = cast<PointerType>(CS.getCalledValue()->getType()); 1032 if (FT->isVarArg()!=cast<FunctionType>(APTy->getElementType())->isVarArg()) 1033 return false; 1034 } 1035 1036 if (FT->getNumParams() < NumActualArgs && FT->isVarArg() && 1037 !CallerPAL.isEmpty()) 1038 // In this case we have more arguments than the new function type, but we 1039 // won't be dropping them. Check that these extra arguments have attributes 1040 // that are compatible with being a vararg call argument. 1041 for (unsigned i = CallerPAL.getNumSlots(); i; --i) { 1042 if (CallerPAL.getSlot(i - 1).Index <= FT->getNumParams()) 1043 break; 1044 Attributes PAttrs = CallerPAL.getSlot(i - 1).Attrs; 1045 if (PAttrs & Attribute::VarArgsIncompatible) 1046 return false; 1047 } 1048 1049 1050 // Okay, we decided that this is a safe thing to do: go ahead and start 1051 // inserting cast instructions as necessary. 1052 std::vector<Value*> Args; 1053 Args.reserve(NumActualArgs); 1054 SmallVector<AttributeWithIndex, 8> attrVec; 1055 attrVec.reserve(NumCommonArgs); 1056 1057 // Get any return attributes. 1058 Attributes RAttrs = CallerPAL.getRetAttributes(); 1059 1060 // If the return value is not being used, the type may not be compatible 1061 // with the existing attributes. Wipe out any problematic attributes. 1062 RAttrs &= ~Attribute::typeIncompatible(NewRetTy); 1063 1064 // Add the new return attributes. 1065 if (RAttrs) 1066 attrVec.push_back(AttributeWithIndex::get(0, RAttrs)); 1067 1068 AI = CS.arg_begin(); 1069 for (unsigned i = 0; i != NumCommonArgs; ++i, ++AI) { 1070 const Type *ParamTy = FT->getParamType(i); 1071 if ((*AI)->getType() == ParamTy) { 1072 Args.push_back(*AI); 1073 } else { 1074 Instruction::CastOps opcode = CastInst::getCastOpcode(*AI, 1075 false, ParamTy, false); 1076 Args.push_back(Builder->CreateCast(opcode, *AI, ParamTy, "tmp")); 1077 } 1078 1079 // Add any parameter attributes. 1080 if (Attributes PAttrs = CallerPAL.getParamAttributes(i + 1)) 1081 attrVec.push_back(AttributeWithIndex::get(i + 1, PAttrs)); 1082 } 1083 1084 // If the function takes more arguments than the call was taking, add them 1085 // now. 1086 for (unsigned i = NumCommonArgs; i != FT->getNumParams(); ++i) 1087 Args.push_back(Constant::getNullValue(FT->getParamType(i))); 1088 1089 // If we are removing arguments to the function, emit an obnoxious warning. 1090 if (FT->getNumParams() < NumActualArgs) { 1091 if (!FT->isVarArg()) { 1092 errs() << "WARNING: While resolving call to function '" 1093 << Callee->getName() << "' arguments were dropped!\n"; 1094 } else { 1095 // Add all of the arguments in their promoted form to the arg list. 1096 for (unsigned i = FT->getNumParams(); i != NumActualArgs; ++i, ++AI) { 1097 const Type *PTy = getPromotedType((*AI)->getType()); 1098 if (PTy != (*AI)->getType()) { 1099 // Must promote to pass through va_arg area! 1100 Instruction::CastOps opcode = 1101 CastInst::getCastOpcode(*AI, false, PTy, false); 1102 Args.push_back(Builder->CreateCast(opcode, *AI, PTy, "tmp")); 1103 } else { 1104 Args.push_back(*AI); 1105 } 1106 1107 // Add any parameter attributes. 1108 if (Attributes PAttrs = CallerPAL.getParamAttributes(i + 1)) 1109 attrVec.push_back(AttributeWithIndex::get(i + 1, PAttrs)); 1110 } 1111 } 1112 } 1113 1114 if (Attributes FnAttrs = CallerPAL.getFnAttributes()) 1115 attrVec.push_back(AttributeWithIndex::get(~0, FnAttrs)); 1116 1117 if (NewRetTy->isVoidTy()) 1118 Caller->setName(""); // Void type should not have a name. 1119 1120 const AttrListPtr &NewCallerPAL = AttrListPtr::get(attrVec.begin(), 1121 attrVec.end()); 1122 1123 Instruction *NC; 1124 if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) { 1125 NC = Builder->CreateInvoke(Callee, II->getNormalDest(), 1126 II->getUnwindDest(), Args.begin(), Args.end()); 1127 NC->takeName(II); 1128 cast<InvokeInst>(NC)->setCallingConv(II->getCallingConv()); 1129 cast<InvokeInst>(NC)->setAttributes(NewCallerPAL); 1130 } else { 1131 CallInst *CI = cast<CallInst>(Caller); 1132 NC = Builder->CreateCall(Callee, Args.begin(), Args.end()); 1133 NC->takeName(CI); 1134 if (CI->isTailCall()) 1135 cast<CallInst>(NC)->setTailCall(); 1136 cast<CallInst>(NC)->setCallingConv(CI->getCallingConv()); 1137 cast<CallInst>(NC)->setAttributes(NewCallerPAL); 1138 } 1139 1140 // Insert a cast of the return type as necessary. 1141 Value *NV = NC; 1142 if (OldRetTy != NV->getType() && !Caller->use_empty()) { 1143 if (!NV->getType()->isVoidTy()) { 1144 Instruction::CastOps opcode = 1145 CastInst::getCastOpcode(NC, false, OldRetTy, false); 1146 NV = NC = CastInst::Create(opcode, NC, OldRetTy, "tmp"); 1147 1148 // If this is an invoke instruction, we should insert it after the first 1149 // non-phi, instruction in the normal successor block. 1150 if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) { 1151 BasicBlock::iterator I = II->getNormalDest()->getFirstNonPHI(); 1152 InsertNewInstBefore(NC, *I); 1153 } else { 1154 // Otherwise, it's a call, just insert cast right after the call. 1155 InsertNewInstBefore(NC, *Caller); 1156 } 1157 Worklist.AddUsersToWorkList(*Caller); 1158 } else { 1159 NV = UndefValue::get(Caller->getType()); 1160 } 1161 } 1162 1163 if (!Caller->use_empty()) 1164 ReplaceInstUsesWith(*Caller, NV); 1165 1166 EraseInstFromFunction(*Caller); 1167 return true; 1168} 1169 1170// transformCallThroughTrampoline - Turn a call to a function created by the 1171// init_trampoline intrinsic into a direct call to the underlying function. 1172// 1173Instruction *InstCombiner::transformCallThroughTrampoline(CallSite CS) { 1174 Value *Callee = CS.getCalledValue(); 1175 const PointerType *PTy = cast<PointerType>(Callee->getType()); 1176 const FunctionType *FTy = cast<FunctionType>(PTy->getElementType()); 1177 const AttrListPtr &Attrs = CS.getAttributes(); 1178 1179 // If the call already has the 'nest' attribute somewhere then give up - 1180 // otherwise 'nest' would occur twice after splicing in the chain. 1181 if (Attrs.hasAttrSomewhere(Attribute::Nest)) 1182 return 0; 1183 1184 IntrinsicInst *Tramp = 1185 cast<IntrinsicInst>(cast<BitCastInst>(Callee)->getOperand(0)); 1186 1187 Function *NestF =cast<Function>(Tramp->getArgOperand(1)->stripPointerCasts()); 1188 const PointerType *NestFPTy = cast<PointerType>(NestF->getType()); 1189 const FunctionType *NestFTy = cast<FunctionType>(NestFPTy->getElementType()); 1190 1191 const AttrListPtr &NestAttrs = NestF->getAttributes(); 1192 if (!NestAttrs.isEmpty()) { 1193 unsigned NestIdx = 1; 1194 const Type *NestTy = 0; 1195 Attributes NestAttr = Attribute::None; 1196 1197 // Look for a parameter marked with the 'nest' attribute. 1198 for (FunctionType::param_iterator I = NestFTy->param_begin(), 1199 E = NestFTy->param_end(); I != E; ++NestIdx, ++I) 1200 if (NestAttrs.paramHasAttr(NestIdx, Attribute::Nest)) { 1201 // Record the parameter type and any other attributes. 1202 NestTy = *I; 1203 NestAttr = NestAttrs.getParamAttributes(NestIdx); 1204 break; 1205 } 1206 1207 if (NestTy) { 1208 Instruction *Caller = CS.getInstruction(); 1209 std::vector<Value*> NewArgs; 1210 NewArgs.reserve(unsigned(CS.arg_end()-CS.arg_begin())+1); 1211 1212 SmallVector<AttributeWithIndex, 8> NewAttrs; 1213 NewAttrs.reserve(Attrs.getNumSlots() + 1); 1214 1215 // Insert the nest argument into the call argument list, which may 1216 // mean appending it. Likewise for attributes. 1217 1218 // Add any result attributes. 1219 if (Attributes Attr = Attrs.getRetAttributes()) 1220 NewAttrs.push_back(AttributeWithIndex::get(0, Attr)); 1221 1222 { 1223 unsigned Idx = 1; 1224 CallSite::arg_iterator I = CS.arg_begin(), E = CS.arg_end(); 1225 do { 1226 if (Idx == NestIdx) { 1227 // Add the chain argument and attributes. 1228 Value *NestVal = Tramp->getArgOperand(2); 1229 if (NestVal->getType() != NestTy) 1230 NestVal = Builder->CreateBitCast(NestVal, NestTy, "nest"); 1231 NewArgs.push_back(NestVal); 1232 NewAttrs.push_back(AttributeWithIndex::get(NestIdx, NestAttr)); 1233 } 1234 1235 if (I == E) 1236 break; 1237 1238 // Add the original argument and attributes. 1239 NewArgs.push_back(*I); 1240 if (Attributes Attr = Attrs.getParamAttributes(Idx)) 1241 NewAttrs.push_back 1242 (AttributeWithIndex::get(Idx + (Idx >= NestIdx), Attr)); 1243 1244 ++Idx, ++I; 1245 } while (1); 1246 } 1247 1248 // Add any function attributes. 1249 if (Attributes Attr = Attrs.getFnAttributes()) 1250 NewAttrs.push_back(AttributeWithIndex::get(~0, Attr)); 1251 1252 // The trampoline may have been bitcast to a bogus type (FTy). 1253 // Handle this by synthesizing a new function type, equal to FTy 1254 // with the chain parameter inserted. 1255 1256 std::vector<const Type*> NewTypes; 1257 NewTypes.reserve(FTy->getNumParams()+1); 1258 1259 // Insert the chain's type into the list of parameter types, which may 1260 // mean appending it. 1261 { 1262 unsigned Idx = 1; 1263 FunctionType::param_iterator I = FTy->param_begin(), 1264 E = FTy->param_end(); 1265 1266 do { 1267 if (Idx == NestIdx) 1268 // Add the chain's type. 1269 NewTypes.push_back(NestTy); 1270 1271 if (I == E) 1272 break; 1273 1274 // Add the original type. 1275 NewTypes.push_back(*I); 1276 1277 ++Idx, ++I; 1278 } while (1); 1279 } 1280 1281 // Replace the trampoline call with a direct call. Let the generic 1282 // code sort out any function type mismatches. 1283 FunctionType *NewFTy = FunctionType::get(FTy->getReturnType(), NewTypes, 1284 FTy->isVarArg()); 1285 Constant *NewCallee = 1286 NestF->getType() == PointerType::getUnqual(NewFTy) ? 1287 NestF : ConstantExpr::getBitCast(NestF, 1288 PointerType::getUnqual(NewFTy)); 1289 const AttrListPtr &NewPAL = AttrListPtr::get(NewAttrs.begin(), 1290 NewAttrs.end()); 1291 1292 Instruction *NewCaller; 1293 if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) { 1294 NewCaller = InvokeInst::Create(NewCallee, 1295 II->getNormalDest(), II->getUnwindDest(), 1296 NewArgs.begin(), NewArgs.end()); 1297 cast<InvokeInst>(NewCaller)->setCallingConv(II->getCallingConv()); 1298 cast<InvokeInst>(NewCaller)->setAttributes(NewPAL); 1299 } else { 1300 NewCaller = CallInst::Create(NewCallee, NewArgs.begin(), NewArgs.end()); 1301 if (cast<CallInst>(Caller)->isTailCall()) 1302 cast<CallInst>(NewCaller)->setTailCall(); 1303 cast<CallInst>(NewCaller)-> 1304 setCallingConv(cast<CallInst>(Caller)->getCallingConv()); 1305 cast<CallInst>(NewCaller)->setAttributes(NewPAL); 1306 } 1307 1308 return NewCaller; 1309 } 1310 } 1311 1312 // Replace the trampoline call with a direct call. Since there is no 'nest' 1313 // parameter, there is no need to adjust the argument list. Let the generic 1314 // code sort out any function type mismatches. 1315 Constant *NewCallee = 1316 NestF->getType() == PTy ? NestF : 1317 ConstantExpr::getBitCast(NestF, PTy); 1318 CS.setCalledFunction(NewCallee); 1319 return CS.getInstruction(); 1320} 1321 1322