InstCombineCalls.cpp revision 240d42d18559a1f75558951ada556baaf289c7f0
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 Instruction *L = new LoadInst(Src, "tmp", MI->isVolatile(), SrcAlign); 115 InsertNewInstBefore(L, *MI); 116 InsertNewInstBefore(new StoreInst(L, Dest, MI->isVolatile(), DstAlign), 117 *MI); 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 InsertNewInstBefore(new StoreInst(ConstantInt::get(ITy, Fill), 158 Dest, false, Alignment), *MI); 159 160 // Set the size of the copy to 0, it will be deleted on the next iteration. 161 MI->setLength(Constant::getNullValue(LenC->getType())); 162 return MI; 163 } 164 165 return 0; 166} 167 168/// visitCallInst - CallInst simplification. This mostly only handles folding 169/// of intrinsic instructions. For normal calls, it allows visitCallSite to do 170/// the heavy lifting. 171/// 172Instruction *InstCombiner::visitCallInst(CallInst &CI) { 173 if (isFreeCall(&CI)) 174 return visitFree(CI); 175 if (isMalloc(&CI)) 176 return visitMalloc(CI); 177 178 // If the caller function is nounwind, mark the call as nounwind, even if the 179 // callee isn't. 180 if (CI.getParent()->getParent()->doesNotThrow() && 181 !CI.doesNotThrow()) { 182 CI.setDoesNotThrow(); 183 return &CI; 184 } 185 186 IntrinsicInst *II = dyn_cast<IntrinsicInst>(&CI); 187 if (!II) return visitCallSite(&CI); 188 189 // Intrinsics cannot occur in an invoke, so handle them here instead of in 190 // visitCallSite. 191 if (MemIntrinsic *MI = dyn_cast<MemIntrinsic>(II)) { 192 bool Changed = false; 193 194 // memmove/cpy/set of zero bytes is a noop. 195 if (Constant *NumBytes = dyn_cast<Constant>(MI->getLength())) { 196 if (NumBytes->isNullValue()) 197 return EraseInstFromFunction(CI); 198 199 if (ConstantInt *CI = dyn_cast<ConstantInt>(NumBytes)) 200 if (CI->getZExtValue() == 1) { 201 // Replace the instruction with just byte operations. We would 202 // transform other cases to loads/stores, but we don't know if 203 // alignment is sufficient. 204 } 205 } 206 207 // No other transformations apply to volatile transfers. 208 if (MI->isVolatile()) 209 return 0; 210 211 // If we have a memmove and the source operation is a constant global, 212 // then the source and dest pointers can't alias, so we can change this 213 // into a call to memcpy. 214 if (MemMoveInst *MMI = dyn_cast<MemMoveInst>(MI)) { 215 if (GlobalVariable *GVSrc = dyn_cast<GlobalVariable>(MMI->getSource())) 216 if (GVSrc->isConstant()) { 217 Module *M = CI.getParent()->getParent()->getParent(); 218 Intrinsic::ID MemCpyID = Intrinsic::memcpy; 219 const Type *Tys[3] = { CI.getArgOperand(0)->getType(), 220 CI.getArgOperand(1)->getType(), 221 CI.getArgOperand(2)->getType() }; 222 CI.setCalledFunction(Intrinsic::getDeclaration(M, MemCpyID, Tys, 3)); 223 Changed = true; 224 } 225 } 226 227 if (MemTransferInst *MTI = dyn_cast<MemTransferInst>(MI)) { 228 // memmove(x,x,size) -> noop. 229 if (MTI->getSource() == MTI->getDest()) 230 return EraseInstFromFunction(CI); 231 } 232 233 // If we can determine a pointer alignment that is bigger than currently 234 // set, update the alignment. 235 if (isa<MemTransferInst>(MI)) { 236 if (Instruction *I = SimplifyMemTransfer(MI)) 237 return I; 238 } else if (MemSetInst *MSI = dyn_cast<MemSetInst>(MI)) { 239 if (Instruction *I = SimplifyMemSet(MSI)) 240 return I; 241 } 242 243 if (Changed) return II; 244 } 245 246 switch (II->getIntrinsicID()) { 247 default: break; 248 case Intrinsic::objectsize: { 249 // We need target data for just about everything so depend on it. 250 if (!TD) break; 251 252 const Type *ReturnTy = CI.getType(); 253 uint64_t DontKnow = II->getArgOperand(1) == Builder->getTrue() ? 0 : -1ULL; 254 255 // Get to the real allocated thing and offset as fast as possible. 256 Value *Op1 = II->getArgOperand(0)->stripPointerCasts(); 257 258 uint64_t Offset = 0; 259 uint64_t Size = -1ULL; 260 261 // Try to look through constant GEPs. 262 if (GEPOperator *GEP = dyn_cast<GEPOperator>(Op1)) { 263 if (!GEP->hasAllConstantIndices()) break; 264 265 // Get the current byte offset into the thing. Use the original 266 // operand in case we're looking through a bitcast. 267 SmallVector<Value*, 8> Ops(GEP->idx_begin(), GEP->idx_end()); 268 Offset = TD->getIndexedOffset(GEP->getPointerOperandType(), 269 Ops.data(), Ops.size()); 270 271 Op1 = GEP->getPointerOperand()->stripPointerCasts(); 272 273 // Make sure we're not a constant offset from an external 274 // global. 275 if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Op1)) 276 if (!GV->hasDefinitiveInitializer()) break; 277 } 278 279 // If we've stripped down to a single global variable that we 280 // can know the size of then just return that. 281 if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Op1)) { 282 if (GV->hasDefinitiveInitializer()) { 283 Constant *C = GV->getInitializer(); 284 Size = TD->getTypeAllocSize(C->getType()); 285 } else { 286 // Can't determine size of the GV. 287 Constant *RetVal = ConstantInt::get(ReturnTy, DontKnow); 288 return ReplaceInstUsesWith(CI, RetVal); 289 } 290 } else if (AllocaInst *AI = dyn_cast<AllocaInst>(Op1)) { 291 // Get alloca size. 292 if (AI->getAllocatedType()->isSized()) { 293 Size = TD->getTypeAllocSize(AI->getAllocatedType()); 294 if (AI->isArrayAllocation()) { 295 const ConstantInt *C = dyn_cast<ConstantInt>(AI->getArraySize()); 296 if (!C) break; 297 Size *= C->getZExtValue(); 298 } 299 } 300 } else if (CallInst *MI = extractMallocCall(Op1)) { 301 // Get allocation size. 302 const Type* MallocType = getMallocAllocatedType(MI); 303 if (MallocType && MallocType->isSized()) 304 if (Value *NElems = getMallocArraySize(MI, TD, true)) 305 if (ConstantInt *NElements = dyn_cast<ConstantInt>(NElems)) 306 Size = NElements->getZExtValue() * TD->getTypeAllocSize(MallocType); 307 308 // If there is no offset we can just return the size passed to malloc. 309 if (Offset == 0) 310 return ReplaceInstUsesWith(CI, MI->getArgOperand(0)); 311 } 312 313 // Do not return "I don't know" here. Later optimization passes could 314 // make it possible to evaluate objectsize to a constant. 315 if (Size == -1ULL) 316 break; 317 318 if (Size < Offset) { 319 // Out of bound reference? Negative index normalized to large 320 // index? Just return "I don't know". 321 return ReplaceInstUsesWith(CI, ConstantInt::get(ReturnTy, DontKnow)); 322 } 323 return ReplaceInstUsesWith(CI, ConstantInt::get(ReturnTy, Size-Offset)); 324 } 325 case Intrinsic::bswap: 326 // bswap(bswap(x)) -> x 327 if (IntrinsicInst *Operand = dyn_cast<IntrinsicInst>(II->getArgOperand(0))) 328 if (Operand->getIntrinsicID() == Intrinsic::bswap) 329 return ReplaceInstUsesWith(CI, Operand->getArgOperand(0)); 330 331 // bswap(trunc(bswap(x))) -> trunc(lshr(x, c)) 332 if (TruncInst *TI = dyn_cast<TruncInst>(II->getArgOperand(0))) { 333 if (IntrinsicInst *Operand = dyn_cast<IntrinsicInst>(TI->getOperand(0))) 334 if (Operand->getIntrinsicID() == Intrinsic::bswap) { 335 unsigned C = Operand->getType()->getPrimitiveSizeInBits() - 336 TI->getType()->getPrimitiveSizeInBits(); 337 Value *CV = ConstantInt::get(Operand->getType(), C); 338 Value *V = Builder->CreateLShr(Operand->getArgOperand(0), CV); 339 return new TruncInst(V, TI->getType()); 340 } 341 } 342 343 break; 344 case Intrinsic::powi: 345 if (ConstantInt *Power = dyn_cast<ConstantInt>(II->getArgOperand(1))) { 346 // powi(x, 0) -> 1.0 347 if (Power->isZero()) 348 return ReplaceInstUsesWith(CI, ConstantFP::get(CI.getType(), 1.0)); 349 // powi(x, 1) -> x 350 if (Power->isOne()) 351 return ReplaceInstUsesWith(CI, II->getArgOperand(0)); 352 // powi(x, -1) -> 1/x 353 if (Power->isAllOnesValue()) 354 return BinaryOperator::CreateFDiv(ConstantFP::get(CI.getType(), 1.0), 355 II->getArgOperand(0)); 356 } 357 break; 358 case Intrinsic::cttz: { 359 // If all bits below the first known one are known zero, 360 // this value is constant. 361 const IntegerType *IT = cast<IntegerType>(II->getArgOperand(0)->getType()); 362 uint32_t BitWidth = IT->getBitWidth(); 363 APInt KnownZero(BitWidth, 0); 364 APInt KnownOne(BitWidth, 0); 365 ComputeMaskedBits(II->getArgOperand(0), APInt::getAllOnesValue(BitWidth), 366 KnownZero, KnownOne); 367 unsigned TrailingZeros = KnownOne.countTrailingZeros(); 368 APInt Mask(APInt::getLowBitsSet(BitWidth, TrailingZeros)); 369 if ((Mask & KnownZero) == Mask) 370 return ReplaceInstUsesWith(CI, ConstantInt::get(IT, 371 APInt(BitWidth, TrailingZeros))); 372 373 } 374 break; 375 case Intrinsic::ctlz: { 376 // If all bits above the first known one are known zero, 377 // this value is constant. 378 const IntegerType *IT = cast<IntegerType>(II->getArgOperand(0)->getType()); 379 uint32_t BitWidth = IT->getBitWidth(); 380 APInt KnownZero(BitWidth, 0); 381 APInt KnownOne(BitWidth, 0); 382 ComputeMaskedBits(II->getArgOperand(0), APInt::getAllOnesValue(BitWidth), 383 KnownZero, KnownOne); 384 unsigned LeadingZeros = KnownOne.countLeadingZeros(); 385 APInt Mask(APInt::getHighBitsSet(BitWidth, LeadingZeros)); 386 if ((Mask & KnownZero) == Mask) 387 return ReplaceInstUsesWith(CI, ConstantInt::get(IT, 388 APInt(BitWidth, LeadingZeros))); 389 390 } 391 break; 392 case Intrinsic::uadd_with_overflow: { 393 Value *LHS = II->getArgOperand(0), *RHS = II->getArgOperand(1); 394 const IntegerType *IT = cast<IntegerType>(II->getArgOperand(0)->getType()); 395 uint32_t BitWidth = IT->getBitWidth(); 396 APInt Mask = APInt::getSignBit(BitWidth); 397 APInt LHSKnownZero(BitWidth, 0); 398 APInt LHSKnownOne(BitWidth, 0); 399 ComputeMaskedBits(LHS, Mask, LHSKnownZero, LHSKnownOne); 400 bool LHSKnownNegative = LHSKnownOne[BitWidth - 1]; 401 bool LHSKnownPositive = LHSKnownZero[BitWidth - 1]; 402 403 if (LHSKnownNegative || LHSKnownPositive) { 404 APInt RHSKnownZero(BitWidth, 0); 405 APInt RHSKnownOne(BitWidth, 0); 406 ComputeMaskedBits(RHS, Mask, RHSKnownZero, RHSKnownOne); 407 bool RHSKnownNegative = RHSKnownOne[BitWidth - 1]; 408 bool RHSKnownPositive = RHSKnownZero[BitWidth - 1]; 409 if (LHSKnownNegative && RHSKnownNegative) { 410 // The sign bit is set in both cases: this MUST overflow. 411 // Create a simple add instruction, and insert it into the struct. 412 Instruction *Add = BinaryOperator::CreateAdd(LHS, RHS, "", &CI); 413 Worklist.Add(Add); 414 Constant *V[] = { 415 UndefValue::get(LHS->getType()),ConstantInt::getTrue(II->getContext()) 416 }; 417 Constant *Struct = ConstantStruct::get(II->getContext(), V, 2, false); 418 return InsertValueInst::Create(Struct, Add, 0); 419 } 420 421 if (LHSKnownPositive && RHSKnownPositive) { 422 // The sign bit is clear in both cases: this CANNOT overflow. 423 // Create a simple add instruction, and insert it into the struct. 424 Instruction *Add = BinaryOperator::CreateNUWAdd(LHS, RHS, "", &CI); 425 Worklist.Add(Add); 426 Constant *V[] = { 427 UndefValue::get(LHS->getType()), 428 ConstantInt::getFalse(II->getContext()) 429 }; 430 Constant *Struct = ConstantStruct::get(II->getContext(), V, 2, false); 431 return InsertValueInst::Create(Struct, Add, 0); 432 } 433 } 434 } 435 // FALL THROUGH uadd into sadd 436 case Intrinsic::sadd_with_overflow: 437 // Canonicalize constants into the RHS. 438 if (isa<Constant>(II->getArgOperand(0)) && 439 !isa<Constant>(II->getArgOperand(1))) { 440 Value *LHS = II->getArgOperand(0); 441 II->setArgOperand(0, II->getArgOperand(1)); 442 II->setArgOperand(1, LHS); 443 return II; 444 } 445 446 // X + undef -> undef 447 if (isa<UndefValue>(II->getArgOperand(1))) 448 return ReplaceInstUsesWith(CI, UndefValue::get(II->getType())); 449 450 if (ConstantInt *RHS = dyn_cast<ConstantInt>(II->getArgOperand(1))) { 451 // X + 0 -> {X, false} 452 if (RHS->isZero()) { 453 Constant *V[] = { 454 UndefValue::get(II->getArgOperand(0)->getType()), 455 ConstantInt::getFalse(II->getContext()) 456 }; 457 Constant *Struct = ConstantStruct::get(II->getContext(), V, 2, false); 458 return InsertValueInst::Create(Struct, II->getArgOperand(0), 0); 459 } 460 } 461 break; 462 case Intrinsic::usub_with_overflow: 463 case Intrinsic::ssub_with_overflow: 464 // undef - X -> undef 465 // X - undef -> undef 466 if (isa<UndefValue>(II->getArgOperand(0)) || 467 isa<UndefValue>(II->getArgOperand(1))) 468 return ReplaceInstUsesWith(CI, UndefValue::get(II->getType())); 469 470 if (ConstantInt *RHS = dyn_cast<ConstantInt>(II->getArgOperand(1))) { 471 // X - 0 -> {X, false} 472 if (RHS->isZero()) { 473 Constant *V[] = { 474 UndefValue::get(II->getArgOperand(0)->getType()), 475 ConstantInt::getFalse(II->getContext()) 476 }; 477 Constant *Struct = ConstantStruct::get(II->getContext(), V, 2, false); 478 return InsertValueInst::Create(Struct, II->getArgOperand(0), 0); 479 } 480 } 481 break; 482 case Intrinsic::umul_with_overflow: 483 case Intrinsic::smul_with_overflow: 484 // Canonicalize constants into the RHS. 485 if (isa<Constant>(II->getArgOperand(0)) && 486 !isa<Constant>(II->getArgOperand(1))) { 487 Value *LHS = II->getArgOperand(0); 488 II->setArgOperand(0, II->getArgOperand(1)); 489 II->setArgOperand(1, LHS); 490 return II; 491 } 492 493 // X * undef -> undef 494 if (isa<UndefValue>(II->getArgOperand(1))) 495 return ReplaceInstUsesWith(CI, UndefValue::get(II->getType())); 496 497 if (ConstantInt *RHSI = dyn_cast<ConstantInt>(II->getArgOperand(1))) { 498 // X*0 -> {0, false} 499 if (RHSI->isZero()) 500 return ReplaceInstUsesWith(CI, Constant::getNullValue(II->getType())); 501 502 // X * 1 -> {X, false} 503 if (RHSI->equalsInt(1)) { 504 Constant *V[] = { 505 UndefValue::get(II->getArgOperand(0)->getType()), 506 ConstantInt::getFalse(II->getContext()) 507 }; 508 Constant *Struct = ConstantStruct::get(II->getContext(), V, 2, false); 509 return InsertValueInst::Create(Struct, II->getArgOperand(0), 0); 510 } 511 } 512 break; 513 case Intrinsic::ppc_altivec_lvx: 514 case Intrinsic::ppc_altivec_lvxl: 515 case Intrinsic::x86_sse_loadu_ps: 516 case Intrinsic::x86_sse2_loadu_pd: 517 case Intrinsic::x86_sse2_loadu_dq: 518 // Turn PPC lvx -> load if the pointer is known aligned. 519 // Turn X86 loadups -> load if the pointer is known aligned. 520 if (getOrEnforceKnownAlignment(II->getArgOperand(0), 16, TD) >= 16) { 521 Value *Ptr = Builder->CreateBitCast(II->getArgOperand(0), 522 PointerType::getUnqual(II->getType())); 523 return new LoadInst(Ptr); 524 } 525 break; 526 case Intrinsic::ppc_altivec_stvx: 527 case Intrinsic::ppc_altivec_stvxl: 528 // Turn stvx -> store if the pointer is known aligned. 529 if (getOrEnforceKnownAlignment(II->getArgOperand(1), 16, TD) >= 16) { 530 const Type *OpPtrTy = 531 PointerType::getUnqual(II->getArgOperand(0)->getType()); 532 Value *Ptr = Builder->CreateBitCast(II->getArgOperand(1), OpPtrTy); 533 return new StoreInst(II->getArgOperand(0), Ptr); 534 } 535 break; 536 case Intrinsic::x86_sse_storeu_ps: 537 case Intrinsic::x86_sse2_storeu_pd: 538 case Intrinsic::x86_sse2_storeu_dq: 539 // Turn X86 storeu -> store if the pointer is known aligned. 540 if (getOrEnforceKnownAlignment(II->getArgOperand(0), 16, TD) >= 16) { 541 const Type *OpPtrTy = 542 PointerType::getUnqual(II->getArgOperand(1)->getType()); 543 Value *Ptr = Builder->CreateBitCast(II->getArgOperand(0), OpPtrTy); 544 return new StoreInst(II->getArgOperand(1), Ptr); 545 } 546 break; 547 548 case Intrinsic::x86_sse_cvttss2si: { 549 // These intrinsics only demands the 0th element of its input vector. If 550 // we can simplify the input based on that, do so now. 551 unsigned VWidth = 552 cast<VectorType>(II->getArgOperand(0)->getType())->getNumElements(); 553 APInt DemandedElts(VWidth, 1); 554 APInt UndefElts(VWidth, 0); 555 if (Value *V = SimplifyDemandedVectorElts(II->getArgOperand(0), 556 DemandedElts, UndefElts)) { 557 II->setArgOperand(0, V); 558 return II; 559 } 560 break; 561 } 562 563 case Intrinsic::ppc_altivec_vperm: 564 // Turn vperm(V1,V2,mask) -> shuffle(V1,V2,mask) if mask is a constant. 565 if (ConstantVector *Mask = dyn_cast<ConstantVector>(II->getArgOperand(2))) { 566 assert(Mask->getNumOperands() == 16 && "Bad type for intrinsic!"); 567 568 // Check that all of the elements are integer constants or undefs. 569 bool AllEltsOk = true; 570 for (unsigned i = 0; i != 16; ++i) { 571 if (!isa<ConstantInt>(Mask->getOperand(i)) && 572 !isa<UndefValue>(Mask->getOperand(i))) { 573 AllEltsOk = false; 574 break; 575 } 576 } 577 578 if (AllEltsOk) { 579 // Cast the input vectors to byte vectors. 580 Value *Op0 = Builder->CreateBitCast(II->getArgOperand(0), 581 Mask->getType()); 582 Value *Op1 = Builder->CreateBitCast(II->getArgOperand(1), 583 Mask->getType()); 584 Value *Result = UndefValue::get(Op0->getType()); 585 586 // Only extract each element once. 587 Value *ExtractedElts[32]; 588 memset(ExtractedElts, 0, sizeof(ExtractedElts)); 589 590 for (unsigned i = 0; i != 16; ++i) { 591 if (isa<UndefValue>(Mask->getOperand(i))) 592 continue; 593 unsigned Idx=cast<ConstantInt>(Mask->getOperand(i))->getZExtValue(); 594 Idx &= 31; // Match the hardware behavior. 595 596 if (ExtractedElts[Idx] == 0) { 597 ExtractedElts[Idx] = 598 Builder->CreateExtractElement(Idx < 16 ? Op0 : Op1, 599 ConstantInt::get(Type::getInt32Ty(II->getContext()), 600 Idx&15, false), "tmp"); 601 } 602 603 // Insert this value into the result vector. 604 Result = Builder->CreateInsertElement(Result, ExtractedElts[Idx], 605 ConstantInt::get(Type::getInt32Ty(II->getContext()), 606 i, false), "tmp"); 607 } 608 return CastInst::Create(Instruction::BitCast, Result, CI.getType()); 609 } 610 } 611 break; 612 613 case Intrinsic::arm_neon_vld1: 614 case Intrinsic::arm_neon_vld2: 615 case Intrinsic::arm_neon_vld3: 616 case Intrinsic::arm_neon_vld4: 617 case Intrinsic::arm_neon_vld2lane: 618 case Intrinsic::arm_neon_vld3lane: 619 case Intrinsic::arm_neon_vld4lane: 620 case Intrinsic::arm_neon_vst1: 621 case Intrinsic::arm_neon_vst2: 622 case Intrinsic::arm_neon_vst3: 623 case Intrinsic::arm_neon_vst4: 624 case Intrinsic::arm_neon_vst2lane: 625 case Intrinsic::arm_neon_vst3lane: 626 case Intrinsic::arm_neon_vst4lane: { 627 unsigned MemAlign = getKnownAlignment(II->getArgOperand(0), TD); 628 unsigned AlignArg = II->getNumArgOperands() - 1; 629 ConstantInt *IntrAlign = dyn_cast<ConstantInt>(II->getArgOperand(AlignArg)); 630 if (IntrAlign && IntrAlign->getZExtValue() < MemAlign) { 631 II->setArgOperand(AlignArg, 632 ConstantInt::get(Type::getInt32Ty(II->getContext()), 633 MemAlign, false)); 634 return II; 635 } 636 break; 637 } 638 639 case Intrinsic::stackrestore: { 640 // If the save is right next to the restore, remove the restore. This can 641 // happen when variable allocas are DCE'd. 642 if (IntrinsicInst *SS = dyn_cast<IntrinsicInst>(II->getArgOperand(0))) { 643 if (SS->getIntrinsicID() == Intrinsic::stacksave) { 644 BasicBlock::iterator BI = SS; 645 if (&*++BI == II) 646 return EraseInstFromFunction(CI); 647 } 648 } 649 650 // Scan down this block to see if there is another stack restore in the 651 // same block without an intervening call/alloca. 652 BasicBlock::iterator BI = II; 653 TerminatorInst *TI = II->getParent()->getTerminator(); 654 bool CannotRemove = false; 655 for (++BI; &*BI != TI; ++BI) { 656 if (isa<AllocaInst>(BI) || isMalloc(BI)) { 657 CannotRemove = true; 658 break; 659 } 660 if (CallInst *BCI = dyn_cast<CallInst>(BI)) { 661 if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(BCI)) { 662 // If there is a stackrestore below this one, remove this one. 663 if (II->getIntrinsicID() == Intrinsic::stackrestore) 664 return EraseInstFromFunction(CI); 665 // Otherwise, ignore the intrinsic. 666 } else { 667 // If we found a non-intrinsic call, we can't remove the stack 668 // restore. 669 CannotRemove = true; 670 break; 671 } 672 } 673 } 674 675 // If the stack restore is in a return/unwind block and if there are no 676 // allocas or calls between the restore and the return, nuke the restore. 677 if (!CannotRemove && (isa<ReturnInst>(TI) || isa<UnwindInst>(TI))) 678 return EraseInstFromFunction(CI); 679 break; 680 } 681 } 682 683 return visitCallSite(II); 684} 685 686// InvokeInst simplification 687// 688Instruction *InstCombiner::visitInvokeInst(InvokeInst &II) { 689 return visitCallSite(&II); 690} 691 692/// isSafeToEliminateVarargsCast - If this cast does not affect the value 693/// passed through the varargs area, we can eliminate the use of the cast. 694static bool isSafeToEliminateVarargsCast(const CallSite CS, 695 const CastInst * const CI, 696 const TargetData * const TD, 697 const int ix) { 698 if (!CI->isLosslessCast()) 699 return false; 700 701 // The size of ByVal arguments is derived from the type, so we 702 // can't change to a type with a different size. If the size were 703 // passed explicitly we could avoid this check. 704 if (!CS.paramHasAttr(ix, Attribute::ByVal)) 705 return true; 706 707 const Type* SrcTy = 708 cast<PointerType>(CI->getOperand(0)->getType())->getElementType(); 709 const Type* DstTy = cast<PointerType>(CI->getType())->getElementType(); 710 if (!SrcTy->isSized() || !DstTy->isSized()) 711 return false; 712 if (!TD || TD->getTypeAllocSize(SrcTy) != TD->getTypeAllocSize(DstTy)) 713 return false; 714 return true; 715} 716 717namespace { 718class InstCombineFortifiedLibCalls : public SimplifyFortifiedLibCalls { 719 InstCombiner *IC; 720protected: 721 void replaceCall(Value *With) { 722 NewInstruction = IC->ReplaceInstUsesWith(*CI, With); 723 } 724 bool isFoldable(unsigned SizeCIOp, unsigned SizeArgOp, bool isString) const { 725 if (ConstantInt *SizeCI = 726 dyn_cast<ConstantInt>(CI->getArgOperand(SizeCIOp))) { 727 if (SizeCI->isAllOnesValue()) 728 return true; 729 if (isString) 730 return SizeCI->getZExtValue() >= 731 GetStringLength(CI->getArgOperand(SizeArgOp)); 732 if (ConstantInt *Arg = dyn_cast<ConstantInt>( 733 CI->getArgOperand(SizeArgOp))) 734 return SizeCI->getZExtValue() >= Arg->getZExtValue(); 735 } 736 return false; 737 } 738public: 739 InstCombineFortifiedLibCalls(InstCombiner *IC) : IC(IC), NewInstruction(0) { } 740 Instruction *NewInstruction; 741}; 742} // end anonymous namespace 743 744// Try to fold some different type of calls here. 745// Currently we're only working with the checking functions, memcpy_chk, 746// mempcpy_chk, memmove_chk, memset_chk, strcpy_chk, stpcpy_chk, strncpy_chk, 747// strcat_chk and strncat_chk. 748Instruction *InstCombiner::tryOptimizeCall(CallInst *CI, const TargetData *TD) { 749 if (CI->getCalledFunction() == 0) return 0; 750 751 InstCombineFortifiedLibCalls Simplifier(this); 752 Simplifier.fold(CI, TD); 753 return Simplifier.NewInstruction; 754} 755 756// visitCallSite - Improvements for call and invoke instructions. 757// 758Instruction *InstCombiner::visitCallSite(CallSite CS) { 759 bool Changed = false; 760 761 // If the callee is a pointer to a function, attempt to move any casts to the 762 // arguments of the call/invoke. 763 Value *Callee = CS.getCalledValue(); 764 if (!isa<Function>(Callee) && transformConstExprCastCall(CS)) 765 return 0; 766 767 if (Function *CalleeF = dyn_cast<Function>(Callee)) 768 // If the call and callee calling conventions don't match, this call must 769 // be unreachable, as the call is undefined. 770 if (CalleeF->getCallingConv() != CS.getCallingConv() && 771 // Only do this for calls to a function with a body. A prototype may 772 // not actually end up matching the implementation's calling conv for a 773 // variety of reasons (e.g. it may be written in assembly). 774 !CalleeF->isDeclaration()) { 775 Instruction *OldCall = CS.getInstruction(); 776 new StoreInst(ConstantInt::getTrue(Callee->getContext()), 777 UndefValue::get(Type::getInt1PtrTy(Callee->getContext())), 778 OldCall); 779 // If OldCall dues not return void then replaceAllUsesWith undef. 780 // This allows ValueHandlers and custom metadata to adjust itself. 781 if (!OldCall->getType()->isVoidTy()) 782 OldCall->replaceAllUsesWith(UndefValue::get(OldCall->getType())); 783 if (isa<CallInst>(OldCall)) 784 return EraseInstFromFunction(*OldCall); 785 786 // We cannot remove an invoke, because it would change the CFG, just 787 // change the callee to a null pointer. 788 cast<InvokeInst>(OldCall)->setCalledFunction( 789 Constant::getNullValue(CalleeF->getType())); 790 return 0; 791 } 792 793 if (isa<ConstantPointerNull>(Callee) || isa<UndefValue>(Callee)) { 794 // This instruction is not reachable, just remove it. We insert a store to 795 // undef so that we know that this code is not reachable, despite the fact 796 // that we can't modify the CFG here. 797 new StoreInst(ConstantInt::getTrue(Callee->getContext()), 798 UndefValue::get(Type::getInt1PtrTy(Callee->getContext())), 799 CS.getInstruction()); 800 801 // If CS does not return void then replaceAllUsesWith undef. 802 // This allows ValueHandlers and custom metadata to adjust itself. 803 if (!CS.getInstruction()->getType()->isVoidTy()) 804 CS.getInstruction()-> 805 replaceAllUsesWith(UndefValue::get(CS.getInstruction()->getType())); 806 807 if (InvokeInst *II = dyn_cast<InvokeInst>(CS.getInstruction())) { 808 // Don't break the CFG, insert a dummy cond branch. 809 BranchInst::Create(II->getNormalDest(), II->getUnwindDest(), 810 ConstantInt::getTrue(Callee->getContext()), II); 811 } 812 return EraseInstFromFunction(*CS.getInstruction()); 813 } 814 815 if (BitCastInst *BC = dyn_cast<BitCastInst>(Callee)) 816 if (IntrinsicInst *In = dyn_cast<IntrinsicInst>(BC->getOperand(0))) 817 if (In->getIntrinsicID() == Intrinsic::init_trampoline) 818 return transformCallThroughTrampoline(CS); 819 820 const PointerType *PTy = cast<PointerType>(Callee->getType()); 821 const FunctionType *FTy = cast<FunctionType>(PTy->getElementType()); 822 if (FTy->isVarArg()) { 823 int ix = FTy->getNumParams() + (isa<InvokeInst>(Callee) ? 3 : 1); 824 // See if we can optimize any arguments passed through the varargs area of 825 // the call. 826 for (CallSite::arg_iterator I = CS.arg_begin()+FTy->getNumParams(), 827 E = CS.arg_end(); I != E; ++I, ++ix) { 828 CastInst *CI = dyn_cast<CastInst>(*I); 829 if (CI && isSafeToEliminateVarargsCast(CS, CI, TD, ix)) { 830 *I = CI->getOperand(0); 831 Changed = true; 832 } 833 } 834 } 835 836 if (isa<InlineAsm>(Callee) && !CS.doesNotThrow()) { 837 // Inline asm calls cannot throw - mark them 'nounwind'. 838 CS.setDoesNotThrow(); 839 Changed = true; 840 } 841 842 // Try to optimize the call if possible, we require TargetData for most of 843 // this. None of these calls are seen as possibly dead so go ahead and 844 // delete the instruction now. 845 if (CallInst *CI = dyn_cast<CallInst>(CS.getInstruction())) { 846 Instruction *I = tryOptimizeCall(CI, TD); 847 // If we changed something return the result, etc. Otherwise let 848 // the fallthrough check. 849 if (I) return EraseInstFromFunction(*I); 850 } 851 852 return Changed ? CS.getInstruction() : 0; 853} 854 855// transformConstExprCastCall - If the callee is a constexpr cast of a function, 856// attempt to move the cast to the arguments of the call/invoke. 857// 858bool InstCombiner::transformConstExprCastCall(CallSite CS) { 859 Function *Callee = 860 dyn_cast<Function>(CS.getCalledValue()->stripPointerCasts()); 861 if (Callee == 0) 862 return false; 863 Instruction *Caller = CS.getInstruction(); 864 const AttrListPtr &CallerPAL = CS.getAttributes(); 865 866 // Okay, this is a cast from a function to a different type. Unless doing so 867 // would cause a type conversion of one of our arguments, change this call to 868 // be a direct call with arguments casted to the appropriate types. 869 // 870 const FunctionType *FT = Callee->getFunctionType(); 871 const Type *OldRetTy = Caller->getType(); 872 const Type *NewRetTy = FT->getReturnType(); 873 874 if (NewRetTy->isStructTy()) 875 return false; // TODO: Handle multiple return values. 876 877 // Check to see if we are changing the return type... 878 if (OldRetTy != NewRetTy) { 879 if (Callee->isDeclaration() && 880 // Conversion is ok if changing from one pointer type to another or from 881 // a pointer to an integer of the same size. 882 !((OldRetTy->isPointerTy() || !TD || 883 OldRetTy == TD->getIntPtrType(Caller->getContext())) && 884 (NewRetTy->isPointerTy() || !TD || 885 NewRetTy == TD->getIntPtrType(Caller->getContext())))) 886 return false; // Cannot transform this return value. 887 888 if (!Caller->use_empty() && 889 // void -> non-void is handled specially 890 !NewRetTy->isVoidTy() && !CastInst::isCastable(NewRetTy, OldRetTy)) 891 return false; // Cannot transform this return value. 892 893 if (!CallerPAL.isEmpty() && !Caller->use_empty()) { 894 Attributes RAttrs = CallerPAL.getRetAttributes(); 895 if (RAttrs & Attribute::typeIncompatible(NewRetTy)) 896 return false; // Attribute not compatible with transformed value. 897 } 898 899 // If the callsite is an invoke instruction, and the return value is used by 900 // a PHI node in a successor, we cannot change the return type of the call 901 // because there is no place to put the cast instruction (without breaking 902 // the critical edge). Bail out in this case. 903 if (!Caller->use_empty()) 904 if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) 905 for (Value::use_iterator UI = II->use_begin(), E = II->use_end(); 906 UI != E; ++UI) 907 if (PHINode *PN = dyn_cast<PHINode>(*UI)) 908 if (PN->getParent() == II->getNormalDest() || 909 PN->getParent() == II->getUnwindDest()) 910 return false; 911 } 912 913 unsigned NumActualArgs = unsigned(CS.arg_end()-CS.arg_begin()); 914 unsigned NumCommonArgs = std::min(FT->getNumParams(), NumActualArgs); 915 916 CallSite::arg_iterator AI = CS.arg_begin(); 917 for (unsigned i = 0, e = NumCommonArgs; i != e; ++i, ++AI) { 918 const Type *ParamTy = FT->getParamType(i); 919 const Type *ActTy = (*AI)->getType(); 920 921 if (!CastInst::isCastable(ActTy, ParamTy)) 922 return false; // Cannot transform this parameter value. 923 924 unsigned Attrs = CallerPAL.getParamAttributes(i + 1); 925 if (Attrs & Attribute::typeIncompatible(ParamTy)) 926 return false; // Attribute not compatible with transformed value. 927 928 // If the parameter is passed as a byval argument, then we have to have a 929 // sized type and the sized type has to have the same size as the old type. 930 if (ParamTy != ActTy && (Attrs & Attribute::ByVal)) { 931 const PointerType *ParamPTy = dyn_cast<PointerType>(ParamTy); 932 if (ParamPTy == 0 || !ParamPTy->getElementType()->isSized() || TD == 0) 933 return false; 934 935 const Type *CurElTy = cast<PointerType>(ActTy)->getElementType(); 936 if (TD->getTypeAllocSize(CurElTy) != 937 TD->getTypeAllocSize(ParamPTy->getElementType())) 938 return false; 939 } 940 941 // Converting from one pointer type to another or between a pointer and an 942 // integer of the same size is safe even if we do not have a body. 943 bool isConvertible = ActTy == ParamTy || 944 (TD && ((ParamTy->isPointerTy() || 945 ParamTy == TD->getIntPtrType(Caller->getContext())) && 946 (ActTy->isPointerTy() || 947 ActTy == TD->getIntPtrType(Caller->getContext())))); 948 if (Callee->isDeclaration() && !isConvertible) return false; 949 } 950 951 if (FT->getNumParams() < NumActualArgs && !FT->isVarArg() && 952 Callee->isDeclaration()) 953 return false; // Do not delete arguments unless we have a function body. 954 955 if (FT->getNumParams() < NumActualArgs && FT->isVarArg() && 956 !CallerPAL.isEmpty()) 957 // In this case we have more arguments than the new function type, but we 958 // won't be dropping them. Check that these extra arguments have attributes 959 // that are compatible with being a vararg call argument. 960 for (unsigned i = CallerPAL.getNumSlots(); i; --i) { 961 if (CallerPAL.getSlot(i - 1).Index <= FT->getNumParams()) 962 break; 963 Attributes PAttrs = CallerPAL.getSlot(i - 1).Attrs; 964 if (PAttrs & Attribute::VarArgsIncompatible) 965 return false; 966 } 967 968 // Okay, we decided that this is a safe thing to do: go ahead and start 969 // inserting cast instructions as necessary... 970 std::vector<Value*> Args; 971 Args.reserve(NumActualArgs); 972 SmallVector<AttributeWithIndex, 8> attrVec; 973 attrVec.reserve(NumCommonArgs); 974 975 // Get any return attributes. 976 Attributes RAttrs = CallerPAL.getRetAttributes(); 977 978 // If the return value is not being used, the type may not be compatible 979 // with the existing attributes. Wipe out any problematic attributes. 980 RAttrs &= ~Attribute::typeIncompatible(NewRetTy); 981 982 // Add the new return attributes. 983 if (RAttrs) 984 attrVec.push_back(AttributeWithIndex::get(0, RAttrs)); 985 986 AI = CS.arg_begin(); 987 for (unsigned i = 0; i != NumCommonArgs; ++i, ++AI) { 988 const Type *ParamTy = FT->getParamType(i); 989 if ((*AI)->getType() == ParamTy) { 990 Args.push_back(*AI); 991 } else { 992 Instruction::CastOps opcode = CastInst::getCastOpcode(*AI, 993 false, ParamTy, false); 994 Args.push_back(Builder->CreateCast(opcode, *AI, ParamTy, "tmp")); 995 } 996 997 // Add any parameter attributes. 998 if (Attributes PAttrs = CallerPAL.getParamAttributes(i + 1)) 999 attrVec.push_back(AttributeWithIndex::get(i + 1, PAttrs)); 1000 } 1001 1002 // If the function takes more arguments than the call was taking, add them 1003 // now. 1004 for (unsigned i = NumCommonArgs; i != FT->getNumParams(); ++i) 1005 Args.push_back(Constant::getNullValue(FT->getParamType(i))); 1006 1007 // If we are removing arguments to the function, emit an obnoxious warning. 1008 if (FT->getNumParams() < NumActualArgs) { 1009 if (!FT->isVarArg()) { 1010 errs() << "WARNING: While resolving call to function '" 1011 << Callee->getName() << "' arguments were dropped!\n"; 1012 } else { 1013 // Add all of the arguments in their promoted form to the arg list. 1014 for (unsigned i = FT->getNumParams(); i != NumActualArgs; ++i, ++AI) { 1015 const Type *PTy = getPromotedType((*AI)->getType()); 1016 if (PTy != (*AI)->getType()) { 1017 // Must promote to pass through va_arg area! 1018 Instruction::CastOps opcode = 1019 CastInst::getCastOpcode(*AI, false, PTy, false); 1020 Args.push_back(Builder->CreateCast(opcode, *AI, PTy, "tmp")); 1021 } else { 1022 Args.push_back(*AI); 1023 } 1024 1025 // Add any parameter attributes. 1026 if (Attributes PAttrs = CallerPAL.getParamAttributes(i + 1)) 1027 attrVec.push_back(AttributeWithIndex::get(i + 1, PAttrs)); 1028 } 1029 } 1030 } 1031 1032 if (Attributes FnAttrs = CallerPAL.getFnAttributes()) 1033 attrVec.push_back(AttributeWithIndex::get(~0, FnAttrs)); 1034 1035 if (NewRetTy->isVoidTy()) 1036 Caller->setName(""); // Void type should not have a name. 1037 1038 const AttrListPtr &NewCallerPAL = AttrListPtr::get(attrVec.begin(), 1039 attrVec.end()); 1040 1041 Instruction *NC; 1042 if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) { 1043 NC = InvokeInst::Create(Callee, II->getNormalDest(), II->getUnwindDest(), 1044 Args.begin(), Args.end(), 1045 Caller->getName(), Caller); 1046 cast<InvokeInst>(NC)->setCallingConv(II->getCallingConv()); 1047 cast<InvokeInst>(NC)->setAttributes(NewCallerPAL); 1048 } else { 1049 NC = CallInst::Create(Callee, Args.begin(), Args.end(), 1050 Caller->getName(), Caller); 1051 CallInst *CI = cast<CallInst>(Caller); 1052 if (CI->isTailCall()) 1053 cast<CallInst>(NC)->setTailCall(); 1054 cast<CallInst>(NC)->setCallingConv(CI->getCallingConv()); 1055 cast<CallInst>(NC)->setAttributes(NewCallerPAL); 1056 } 1057 1058 // Insert a cast of the return type as necessary. 1059 Value *NV = NC; 1060 if (OldRetTy != NV->getType() && !Caller->use_empty()) { 1061 if (!NV->getType()->isVoidTy()) { 1062 Instruction::CastOps opcode = 1063 CastInst::getCastOpcode(NC, false, OldRetTy, false); 1064 NV = NC = CastInst::Create(opcode, NC, OldRetTy, "tmp"); 1065 1066 // If this is an invoke instruction, we should insert it after the first 1067 // non-phi, instruction in the normal successor block. 1068 if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) { 1069 BasicBlock::iterator I = II->getNormalDest()->getFirstNonPHI(); 1070 InsertNewInstBefore(NC, *I); 1071 } else { 1072 // Otherwise, it's a call, just insert cast right after the call. 1073 InsertNewInstBefore(NC, *Caller); 1074 } 1075 Worklist.AddUsersToWorkList(*Caller); 1076 } else { 1077 NV = UndefValue::get(Caller->getType()); 1078 } 1079 } 1080 1081 if (!Caller->use_empty()) 1082 Caller->replaceAllUsesWith(NV); 1083 1084 EraseInstFromFunction(*Caller); 1085 return true; 1086} 1087 1088// transformCallThroughTrampoline - Turn a call to a function created by the 1089// init_trampoline intrinsic into a direct call to the underlying function. 1090// 1091Instruction *InstCombiner::transformCallThroughTrampoline(CallSite CS) { 1092 Value *Callee = CS.getCalledValue(); 1093 const PointerType *PTy = cast<PointerType>(Callee->getType()); 1094 const FunctionType *FTy = cast<FunctionType>(PTy->getElementType()); 1095 const AttrListPtr &Attrs = CS.getAttributes(); 1096 1097 // If the call already has the 'nest' attribute somewhere then give up - 1098 // otherwise 'nest' would occur twice after splicing in the chain. 1099 if (Attrs.hasAttrSomewhere(Attribute::Nest)) 1100 return 0; 1101 1102 IntrinsicInst *Tramp = 1103 cast<IntrinsicInst>(cast<BitCastInst>(Callee)->getOperand(0)); 1104 1105 Function *NestF =cast<Function>(Tramp->getArgOperand(1)->stripPointerCasts()); 1106 const PointerType *NestFPTy = cast<PointerType>(NestF->getType()); 1107 const FunctionType *NestFTy = cast<FunctionType>(NestFPTy->getElementType()); 1108 1109 const AttrListPtr &NestAttrs = NestF->getAttributes(); 1110 if (!NestAttrs.isEmpty()) { 1111 unsigned NestIdx = 1; 1112 const Type *NestTy = 0; 1113 Attributes NestAttr = Attribute::None; 1114 1115 // Look for a parameter marked with the 'nest' attribute. 1116 for (FunctionType::param_iterator I = NestFTy->param_begin(), 1117 E = NestFTy->param_end(); I != E; ++NestIdx, ++I) 1118 if (NestAttrs.paramHasAttr(NestIdx, Attribute::Nest)) { 1119 // Record the parameter type and any other attributes. 1120 NestTy = *I; 1121 NestAttr = NestAttrs.getParamAttributes(NestIdx); 1122 break; 1123 } 1124 1125 if (NestTy) { 1126 Instruction *Caller = CS.getInstruction(); 1127 std::vector<Value*> NewArgs; 1128 NewArgs.reserve(unsigned(CS.arg_end()-CS.arg_begin())+1); 1129 1130 SmallVector<AttributeWithIndex, 8> NewAttrs; 1131 NewAttrs.reserve(Attrs.getNumSlots() + 1); 1132 1133 // Insert the nest argument into the call argument list, which may 1134 // mean appending it. Likewise for attributes. 1135 1136 // Add any result attributes. 1137 if (Attributes Attr = Attrs.getRetAttributes()) 1138 NewAttrs.push_back(AttributeWithIndex::get(0, Attr)); 1139 1140 { 1141 unsigned Idx = 1; 1142 CallSite::arg_iterator I = CS.arg_begin(), E = CS.arg_end(); 1143 do { 1144 if (Idx == NestIdx) { 1145 // Add the chain argument and attributes. 1146 Value *NestVal = Tramp->getArgOperand(2); 1147 if (NestVal->getType() != NestTy) 1148 NestVal = new BitCastInst(NestVal, NestTy, "nest", Caller); 1149 NewArgs.push_back(NestVal); 1150 NewAttrs.push_back(AttributeWithIndex::get(NestIdx, NestAttr)); 1151 } 1152 1153 if (I == E) 1154 break; 1155 1156 // Add the original argument and attributes. 1157 NewArgs.push_back(*I); 1158 if (Attributes Attr = Attrs.getParamAttributes(Idx)) 1159 NewAttrs.push_back 1160 (AttributeWithIndex::get(Idx + (Idx >= NestIdx), Attr)); 1161 1162 ++Idx, ++I; 1163 } while (1); 1164 } 1165 1166 // Add any function attributes. 1167 if (Attributes Attr = Attrs.getFnAttributes()) 1168 NewAttrs.push_back(AttributeWithIndex::get(~0, Attr)); 1169 1170 // The trampoline may have been bitcast to a bogus type (FTy). 1171 // Handle this by synthesizing a new function type, equal to FTy 1172 // with the chain parameter inserted. 1173 1174 std::vector<const Type*> NewTypes; 1175 NewTypes.reserve(FTy->getNumParams()+1); 1176 1177 // Insert the chain's type into the list of parameter types, which may 1178 // mean appending it. 1179 { 1180 unsigned Idx = 1; 1181 FunctionType::param_iterator I = FTy->param_begin(), 1182 E = FTy->param_end(); 1183 1184 do { 1185 if (Idx == NestIdx) 1186 // Add the chain's type. 1187 NewTypes.push_back(NestTy); 1188 1189 if (I == E) 1190 break; 1191 1192 // Add the original type. 1193 NewTypes.push_back(*I); 1194 1195 ++Idx, ++I; 1196 } while (1); 1197 } 1198 1199 // Replace the trampoline call with a direct call. Let the generic 1200 // code sort out any function type mismatches. 1201 FunctionType *NewFTy = FunctionType::get(FTy->getReturnType(), NewTypes, 1202 FTy->isVarArg()); 1203 Constant *NewCallee = 1204 NestF->getType() == PointerType::getUnqual(NewFTy) ? 1205 NestF : ConstantExpr::getBitCast(NestF, 1206 PointerType::getUnqual(NewFTy)); 1207 const AttrListPtr &NewPAL = AttrListPtr::get(NewAttrs.begin(), 1208 NewAttrs.end()); 1209 1210 Instruction *NewCaller; 1211 if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) { 1212 NewCaller = InvokeInst::Create(NewCallee, 1213 II->getNormalDest(), II->getUnwindDest(), 1214 NewArgs.begin(), NewArgs.end(), 1215 Caller->getName(), Caller); 1216 cast<InvokeInst>(NewCaller)->setCallingConv(II->getCallingConv()); 1217 cast<InvokeInst>(NewCaller)->setAttributes(NewPAL); 1218 } else { 1219 NewCaller = CallInst::Create(NewCallee, NewArgs.begin(), NewArgs.end(), 1220 Caller->getName(), Caller); 1221 if (cast<CallInst>(Caller)->isTailCall()) 1222 cast<CallInst>(NewCaller)->setTailCall(); 1223 cast<CallInst>(NewCaller)-> 1224 setCallingConv(cast<CallInst>(Caller)->getCallingConv()); 1225 cast<CallInst>(NewCaller)->setAttributes(NewPAL); 1226 } 1227 if (!Caller->getType()->isVoidTy()) 1228 Caller->replaceAllUsesWith(NewCaller); 1229 Caller->eraseFromParent(); 1230 Worklist.Remove(Caller); 1231 return 0; 1232 } 1233 } 1234 1235 // Replace the trampoline call with a direct call. Since there is no 'nest' 1236 // parameter, there is no need to adjust the argument list. Let the generic 1237 // code sort out any function type mismatches. 1238 Constant *NewCallee = 1239 NestF->getType() == PTy ? NestF : 1240 ConstantExpr::getBitCast(NestF, PTy); 1241 CS.setCalledFunction(NewCallee); 1242 return CS.getInstruction(); 1243} 1244 1245