1 //===--- CGAtomic.cpp - Emit LLVM IR for atomic operations ----------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file contains the code for emitting atomic operations. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #include "CGCall.h" 14 #include "CGRecordLayout.h" 15 #include "CodeGenFunction.h" 16 #include "CodeGenModule.h" 17 #include "TargetInfo.h" 18 #include "clang/AST/ASTContext.h" 19 #include "clang/CodeGen/CGFunctionInfo.h" 20 #include "clang/Frontend/FrontendDiagnostic.h" 21 #include "llvm/ADT/DenseMap.h" 22 #include "llvm/IR/DataLayout.h" 23 #include "llvm/IR/Intrinsics.h" 24 #include "llvm/IR/Operator.h" 25 26 using namespace clang; 27 using namespace CodeGen; 28 29 namespace { 30 class AtomicInfo { 31 CodeGenFunction &CGF; 32 QualType AtomicTy; 33 QualType ValueTy; 34 uint64_t AtomicSizeInBits; 35 uint64_t ValueSizeInBits; 36 CharUnits AtomicAlign; 37 CharUnits ValueAlign; 38 TypeEvaluationKind EvaluationKind; 39 bool UseLibcall; 40 LValue LVal; 41 CGBitFieldInfo BFI; 42 public: 43 AtomicInfo(CodeGenFunction &CGF, LValue &lvalue) 44 : CGF(CGF), AtomicSizeInBits(0), ValueSizeInBits(0), 45 EvaluationKind(TEK_Scalar), UseLibcall(true) { 46 assert(!lvalue.isGlobalReg()); 47 ASTContext &C = CGF.getContext(); 48 if (lvalue.isSimple()) { 49 AtomicTy = lvalue.getType(); 50 if (auto *ATy = AtomicTy->getAs<AtomicType>()) 51 ValueTy = ATy->getValueType(); 52 else 53 ValueTy = AtomicTy; 54 EvaluationKind = CGF.getEvaluationKind(ValueTy); 55 56 uint64_t ValueAlignInBits; 57 uint64_t AtomicAlignInBits; 58 TypeInfo ValueTI = C.getTypeInfo(ValueTy); 59 ValueSizeInBits = ValueTI.Width; 60 ValueAlignInBits = ValueTI.Align; 61 62 TypeInfo AtomicTI = C.getTypeInfo(AtomicTy); 63 AtomicSizeInBits = AtomicTI.Width; 64 AtomicAlignInBits = AtomicTI.Align; 65 66 assert(ValueSizeInBits <= AtomicSizeInBits); 67 assert(ValueAlignInBits <= AtomicAlignInBits); 68 69 AtomicAlign = C.toCharUnitsFromBits(AtomicAlignInBits); 70 ValueAlign = C.toCharUnitsFromBits(ValueAlignInBits); 71 if (lvalue.getAlignment().isZero()) 72 lvalue.setAlignment(AtomicAlign); 73 74 LVal = lvalue; 75 } else if (lvalue.isBitField()) { 76 ValueTy = lvalue.getType(); 77 ValueSizeInBits = C.getTypeSize(ValueTy); 78 auto &OrigBFI = lvalue.getBitFieldInfo(); 79 auto Offset = OrigBFI.Offset % C.toBits(lvalue.getAlignment()); 80 AtomicSizeInBits = C.toBits( 81 C.toCharUnitsFromBits(Offset + OrigBFI.Size + C.getCharWidth() - 1) 82 .alignTo(lvalue.getAlignment())); 83 auto VoidPtrAddr = CGF.EmitCastToVoidPtr(lvalue.getBitFieldPointer()); 84 auto OffsetInChars = 85 (C.toCharUnitsFromBits(OrigBFI.Offset) / lvalue.getAlignment()) * 86 lvalue.getAlignment(); 87 VoidPtrAddr = CGF.Builder.CreateConstGEP1_64( 88 VoidPtrAddr, OffsetInChars.getQuantity()); 89 auto Addr = CGF.Builder.CreatePointerBitCastOrAddrSpaceCast( 90 VoidPtrAddr, 91 CGF.Builder.getIntNTy(AtomicSizeInBits)->getPointerTo(), 92 "atomic_bitfield_base"); 93 BFI = OrigBFI; 94 BFI.Offset = Offset; 95 BFI.StorageSize = AtomicSizeInBits; 96 BFI.StorageOffset += OffsetInChars; 97 LVal = LValue::MakeBitfield(Address(Addr, lvalue.getAlignment()), 98 BFI, lvalue.getType(), lvalue.getBaseInfo(), 99 lvalue.getTBAAInfo()); 100 AtomicTy = C.getIntTypeForBitwidth(AtomicSizeInBits, OrigBFI.IsSigned); 101 if (AtomicTy.isNull()) { 102 llvm::APInt Size( 103 /*numBits=*/32, 104 C.toCharUnitsFromBits(AtomicSizeInBits).getQuantity()); 105 AtomicTy = 106 C.getConstantArrayType(C.CharTy, Size, nullptr, ArrayType::Normal, 107 /*IndexTypeQuals=*/0); 108 } 109 AtomicAlign = ValueAlign = lvalue.getAlignment(); 110 } else if (lvalue.isVectorElt()) { 111 ValueTy = lvalue.getType()->castAs<VectorType>()->getElementType(); 112 ValueSizeInBits = C.getTypeSize(ValueTy); 113 AtomicTy = lvalue.getType(); 114 AtomicSizeInBits = C.getTypeSize(AtomicTy); 115 AtomicAlign = ValueAlign = lvalue.getAlignment(); 116 LVal = lvalue; 117 } else { 118 assert(lvalue.isExtVectorElt()); 119 ValueTy = lvalue.getType(); 120 ValueSizeInBits = C.getTypeSize(ValueTy); 121 AtomicTy = ValueTy = CGF.getContext().getExtVectorType( 122 lvalue.getType(), cast<llvm::VectorType>( 123 lvalue.getExtVectorAddress().getElementType()) 124 ->getNumElements()); 125 AtomicSizeInBits = C.getTypeSize(AtomicTy); 126 AtomicAlign = ValueAlign = lvalue.getAlignment(); 127 LVal = lvalue; 128 } 129 UseLibcall = !C.getTargetInfo().hasBuiltinAtomic( 130 AtomicSizeInBits, C.toBits(lvalue.getAlignment())); 131 } 132 133 QualType getAtomicType() const { return AtomicTy; } 134 QualType getValueType() const { return ValueTy; } 135 CharUnits getAtomicAlignment() const { return AtomicAlign; } 136 uint64_t getAtomicSizeInBits() const { return AtomicSizeInBits; } 137 uint64_t getValueSizeInBits() const { return ValueSizeInBits; } 138 TypeEvaluationKind getEvaluationKind() const { return EvaluationKind; } 139 bool shouldUseLibcall() const { return UseLibcall; } 140 const LValue &getAtomicLValue() const { return LVal; } 141 llvm::Value *getAtomicPointer() const { 142 if (LVal.isSimple()) 143 return LVal.getPointer(CGF); 144 else if (LVal.isBitField()) 145 return LVal.getBitFieldPointer(); 146 else if (LVal.isVectorElt()) 147 return LVal.getVectorPointer(); 148 assert(LVal.isExtVectorElt()); 149 return LVal.getExtVectorPointer(); 150 } 151 Address getAtomicAddress() const { 152 return Address(getAtomicPointer(), getAtomicAlignment()); 153 } 154 155 Address getAtomicAddressAsAtomicIntPointer() const { 156 return emitCastToAtomicIntPointer(getAtomicAddress()); 157 } 158 159 /// Is the atomic size larger than the underlying value type? 160 /// 161 /// Note that the absence of padding does not mean that atomic 162 /// objects are completely interchangeable with non-atomic 163 /// objects: we might have promoted the alignment of a type 164 /// without making it bigger. 165 bool hasPadding() const { 166 return (ValueSizeInBits != AtomicSizeInBits); 167 } 168 169 bool emitMemSetZeroIfNecessary() const; 170 171 llvm::Value *getAtomicSizeValue() const { 172 CharUnits size = CGF.getContext().toCharUnitsFromBits(AtomicSizeInBits); 173 return CGF.CGM.getSize(size); 174 } 175 176 /// Cast the given pointer to an integer pointer suitable for atomic 177 /// operations if the source. 178 Address emitCastToAtomicIntPointer(Address Addr) const; 179 180 /// If Addr is compatible with the iN that will be used for an atomic 181 /// operation, bitcast it. Otherwise, create a temporary that is suitable 182 /// and copy the value across. 183 Address convertToAtomicIntPointer(Address Addr) const; 184 185 /// Turn an atomic-layout object into an r-value. 186 RValue convertAtomicTempToRValue(Address addr, AggValueSlot resultSlot, 187 SourceLocation loc, bool AsValue) const; 188 189 /// Converts a rvalue to integer value. 190 llvm::Value *convertRValueToInt(RValue RVal) const; 191 192 RValue ConvertIntToValueOrAtomic(llvm::Value *IntVal, 193 AggValueSlot ResultSlot, 194 SourceLocation Loc, bool AsValue) const; 195 196 /// Copy an atomic r-value into atomic-layout memory. 197 void emitCopyIntoMemory(RValue rvalue) const; 198 199 /// Project an l-value down to the value field. 200 LValue projectValue() const { 201 assert(LVal.isSimple()); 202 Address addr = getAtomicAddress(); 203 if (hasPadding()) 204 addr = CGF.Builder.CreateStructGEP(addr, 0); 205 206 return LValue::MakeAddr(addr, getValueType(), CGF.getContext(), 207 LVal.getBaseInfo(), LVal.getTBAAInfo()); 208 } 209 210 /// Emits atomic load. 211 /// \returns Loaded value. 212 RValue EmitAtomicLoad(AggValueSlot ResultSlot, SourceLocation Loc, 213 bool AsValue, llvm::AtomicOrdering AO, 214 bool IsVolatile); 215 216 /// Emits atomic compare-and-exchange sequence. 217 /// \param Expected Expected value. 218 /// \param Desired Desired value. 219 /// \param Success Atomic ordering for success operation. 220 /// \param Failure Atomic ordering for failed operation. 221 /// \param IsWeak true if atomic operation is weak, false otherwise. 222 /// \returns Pair of values: previous value from storage (value type) and 223 /// boolean flag (i1 type) with true if success and false otherwise. 224 std::pair<RValue, llvm::Value *> 225 EmitAtomicCompareExchange(RValue Expected, RValue Desired, 226 llvm::AtomicOrdering Success = 227 llvm::AtomicOrdering::SequentiallyConsistent, 228 llvm::AtomicOrdering Failure = 229 llvm::AtomicOrdering::SequentiallyConsistent, 230 bool IsWeak = false); 231 232 /// Emits atomic update. 233 /// \param AO Atomic ordering. 234 /// \param UpdateOp Update operation for the current lvalue. 235 void EmitAtomicUpdate(llvm::AtomicOrdering AO, 236 const llvm::function_ref<RValue(RValue)> &UpdateOp, 237 bool IsVolatile); 238 /// Emits atomic update. 239 /// \param AO Atomic ordering. 240 void EmitAtomicUpdate(llvm::AtomicOrdering AO, RValue UpdateRVal, 241 bool IsVolatile); 242 243 /// Materialize an atomic r-value in atomic-layout memory. 244 Address materializeRValue(RValue rvalue) const; 245 246 /// Creates temp alloca for intermediate operations on atomic value. 247 Address CreateTempAlloca() const; 248 private: 249 bool requiresMemSetZero(llvm::Type *type) const; 250 251 252 /// Emits atomic load as a libcall. 253 void EmitAtomicLoadLibcall(llvm::Value *AddForLoaded, 254 llvm::AtomicOrdering AO, bool IsVolatile); 255 /// Emits atomic load as LLVM instruction. 256 llvm::Value *EmitAtomicLoadOp(llvm::AtomicOrdering AO, bool IsVolatile); 257 /// Emits atomic compare-and-exchange op as a libcall. 258 llvm::Value *EmitAtomicCompareExchangeLibcall( 259 llvm::Value *ExpectedAddr, llvm::Value *DesiredAddr, 260 llvm::AtomicOrdering Success = 261 llvm::AtomicOrdering::SequentiallyConsistent, 262 llvm::AtomicOrdering Failure = 263 llvm::AtomicOrdering::SequentiallyConsistent); 264 /// Emits atomic compare-and-exchange op as LLVM instruction. 265 std::pair<llvm::Value *, llvm::Value *> EmitAtomicCompareExchangeOp( 266 llvm::Value *ExpectedVal, llvm::Value *DesiredVal, 267 llvm::AtomicOrdering Success = 268 llvm::AtomicOrdering::SequentiallyConsistent, 269 llvm::AtomicOrdering Failure = 270 llvm::AtomicOrdering::SequentiallyConsistent, 271 bool IsWeak = false); 272 /// Emit atomic update as libcalls. 273 void 274 EmitAtomicUpdateLibcall(llvm::AtomicOrdering AO, 275 const llvm::function_ref<RValue(RValue)> &UpdateOp, 276 bool IsVolatile); 277 /// Emit atomic update as LLVM instructions. 278 void EmitAtomicUpdateOp(llvm::AtomicOrdering AO, 279 const llvm::function_ref<RValue(RValue)> &UpdateOp, 280 bool IsVolatile); 281 /// Emit atomic update as libcalls. 282 void EmitAtomicUpdateLibcall(llvm::AtomicOrdering AO, RValue UpdateRVal, 283 bool IsVolatile); 284 /// Emit atomic update as LLVM instructions. 285 void EmitAtomicUpdateOp(llvm::AtomicOrdering AO, RValue UpdateRal, 286 bool IsVolatile); 287 }; 288 } 289 290 Address AtomicInfo::CreateTempAlloca() const { 291 Address TempAlloca = CGF.CreateMemTemp( 292 (LVal.isBitField() && ValueSizeInBits > AtomicSizeInBits) ? ValueTy 293 : AtomicTy, 294 getAtomicAlignment(), 295 "atomic-temp"); 296 // Cast to pointer to value type for bitfields. 297 if (LVal.isBitField()) 298 return CGF.Builder.CreatePointerBitCastOrAddrSpaceCast( 299 TempAlloca, getAtomicAddress().getType()); 300 return TempAlloca; 301 } 302 303 static RValue emitAtomicLibcall(CodeGenFunction &CGF, 304 StringRef fnName, 305 QualType resultType, 306 CallArgList &args) { 307 const CGFunctionInfo &fnInfo = 308 CGF.CGM.getTypes().arrangeBuiltinFunctionCall(resultType, args); 309 llvm::FunctionType *fnTy = CGF.CGM.getTypes().GetFunctionType(fnInfo); 310 llvm::FunctionCallee fn = CGF.CGM.CreateRuntimeFunction(fnTy, fnName); 311 auto callee = CGCallee::forDirect(fn); 312 return CGF.EmitCall(fnInfo, callee, ReturnValueSlot(), args); 313 } 314 315 /// Does a store of the given IR type modify the full expected width? 316 static bool isFullSizeType(CodeGenModule &CGM, llvm::Type *type, 317 uint64_t expectedSize) { 318 return (CGM.getDataLayout().getTypeStoreSize(type) * 8 == expectedSize); 319 } 320 321 /// Does the atomic type require memsetting to zero before initialization? 322 /// 323 /// The IR type is provided as a way of making certain queries faster. 324 bool AtomicInfo::requiresMemSetZero(llvm::Type *type) const { 325 // If the atomic type has size padding, we definitely need a memset. 326 if (hasPadding()) return true; 327 328 // Otherwise, do some simple heuristics to try to avoid it: 329 switch (getEvaluationKind()) { 330 // For scalars and complexes, check whether the store size of the 331 // type uses the full size. 332 case TEK_Scalar: 333 return !isFullSizeType(CGF.CGM, type, AtomicSizeInBits); 334 case TEK_Complex: 335 return !isFullSizeType(CGF.CGM, type->getStructElementType(0), 336 AtomicSizeInBits / 2); 337 338 // Padding in structs has an undefined bit pattern. User beware. 339 case TEK_Aggregate: 340 return false; 341 } 342 llvm_unreachable("bad evaluation kind"); 343 } 344 345 bool AtomicInfo::emitMemSetZeroIfNecessary() const { 346 assert(LVal.isSimple()); 347 llvm::Value *addr = LVal.getPointer(CGF); 348 if (!requiresMemSetZero(addr->getType()->getPointerElementType())) 349 return false; 350 351 CGF.Builder.CreateMemSet( 352 addr, llvm::ConstantInt::get(CGF.Int8Ty, 0), 353 CGF.getContext().toCharUnitsFromBits(AtomicSizeInBits).getQuantity(), 354 LVal.getAlignment().getAsAlign()); 355 return true; 356 } 357 358 static void emitAtomicCmpXchg(CodeGenFunction &CGF, AtomicExpr *E, bool IsWeak, 359 Address Dest, Address Ptr, 360 Address Val1, Address Val2, 361 uint64_t Size, 362 llvm::AtomicOrdering SuccessOrder, 363 llvm::AtomicOrdering FailureOrder, 364 llvm::SyncScope::ID Scope) { 365 // Note that cmpxchg doesn't support weak cmpxchg, at least at the moment. 366 llvm::Value *Expected = CGF.Builder.CreateLoad(Val1); 367 llvm::Value *Desired = CGF.Builder.CreateLoad(Val2); 368 369 llvm::AtomicCmpXchgInst *Pair = CGF.Builder.CreateAtomicCmpXchg( 370 Ptr.getPointer(), Expected, Desired, SuccessOrder, FailureOrder, 371 Scope); 372 Pair->setVolatile(E->isVolatile()); 373 Pair->setWeak(IsWeak); 374 375 // Cmp holds the result of the compare-exchange operation: true on success, 376 // false on failure. 377 llvm::Value *Old = CGF.Builder.CreateExtractValue(Pair, 0); 378 llvm::Value *Cmp = CGF.Builder.CreateExtractValue(Pair, 1); 379 380 // This basic block is used to hold the store instruction if the operation 381 // failed. 382 llvm::BasicBlock *StoreExpectedBB = 383 CGF.createBasicBlock("cmpxchg.store_expected", CGF.CurFn); 384 385 // This basic block is the exit point of the operation, we should end up 386 // here regardless of whether or not the operation succeeded. 387 llvm::BasicBlock *ContinueBB = 388 CGF.createBasicBlock("cmpxchg.continue", CGF.CurFn); 389 390 // Update Expected if Expected isn't equal to Old, otherwise branch to the 391 // exit point. 392 CGF.Builder.CreateCondBr(Cmp, ContinueBB, StoreExpectedBB); 393 394 CGF.Builder.SetInsertPoint(StoreExpectedBB); 395 // Update the memory at Expected with Old's value. 396 CGF.Builder.CreateStore(Old, Val1); 397 // Finally, branch to the exit point. 398 CGF.Builder.CreateBr(ContinueBB); 399 400 CGF.Builder.SetInsertPoint(ContinueBB); 401 // Update the memory at Dest with Cmp's value. 402 CGF.EmitStoreOfScalar(Cmp, CGF.MakeAddrLValue(Dest, E->getType())); 403 } 404 405 /// Given an ordering required on success, emit all possible cmpxchg 406 /// instructions to cope with the provided (but possibly only dynamically known) 407 /// FailureOrder. 408 static void emitAtomicCmpXchgFailureSet(CodeGenFunction &CGF, AtomicExpr *E, 409 bool IsWeak, Address Dest, Address Ptr, 410 Address Val1, Address Val2, 411 llvm::Value *FailureOrderVal, 412 uint64_t Size, 413 llvm::AtomicOrdering SuccessOrder, 414 llvm::SyncScope::ID Scope) { 415 llvm::AtomicOrdering FailureOrder; 416 if (llvm::ConstantInt *FO = dyn_cast<llvm::ConstantInt>(FailureOrderVal)) { 417 auto FOS = FO->getSExtValue(); 418 if (!llvm::isValidAtomicOrderingCABI(FOS)) 419 FailureOrder = llvm::AtomicOrdering::Monotonic; 420 else 421 switch ((llvm::AtomicOrderingCABI)FOS) { 422 case llvm::AtomicOrderingCABI::relaxed: 423 case llvm::AtomicOrderingCABI::release: 424 case llvm::AtomicOrderingCABI::acq_rel: 425 FailureOrder = llvm::AtomicOrdering::Monotonic; 426 break; 427 case llvm::AtomicOrderingCABI::consume: 428 case llvm::AtomicOrderingCABI::acquire: 429 FailureOrder = llvm::AtomicOrdering::Acquire; 430 break; 431 case llvm::AtomicOrderingCABI::seq_cst: 432 FailureOrder = llvm::AtomicOrdering::SequentiallyConsistent; 433 break; 434 } 435 if (isStrongerThan(FailureOrder, SuccessOrder)) { 436 // Don't assert on undefined behavior "failure argument shall be no 437 // stronger than the success argument". 438 FailureOrder = 439 llvm::AtomicCmpXchgInst::getStrongestFailureOrdering(SuccessOrder); 440 } 441 emitAtomicCmpXchg(CGF, E, IsWeak, Dest, Ptr, Val1, Val2, Size, SuccessOrder, 442 FailureOrder, Scope); 443 return; 444 } 445 446 // Create all the relevant BB's 447 llvm::BasicBlock *MonotonicBB = nullptr, *AcquireBB = nullptr, 448 *SeqCstBB = nullptr; 449 MonotonicBB = CGF.createBasicBlock("monotonic_fail", CGF.CurFn); 450 if (SuccessOrder != llvm::AtomicOrdering::Monotonic && 451 SuccessOrder != llvm::AtomicOrdering::Release) 452 AcquireBB = CGF.createBasicBlock("acquire_fail", CGF.CurFn); 453 if (SuccessOrder == llvm::AtomicOrdering::SequentiallyConsistent) 454 SeqCstBB = CGF.createBasicBlock("seqcst_fail", CGF.CurFn); 455 456 llvm::BasicBlock *ContBB = CGF.createBasicBlock("atomic.continue", CGF.CurFn); 457 458 llvm::SwitchInst *SI = CGF.Builder.CreateSwitch(FailureOrderVal, MonotonicBB); 459 460 // Emit all the different atomics 461 462 // MonotonicBB is arbitrarily chosen as the default case; in practice, this 463 // doesn't matter unless someone is crazy enough to use something that 464 // doesn't fold to a constant for the ordering. 465 CGF.Builder.SetInsertPoint(MonotonicBB); 466 emitAtomicCmpXchg(CGF, E, IsWeak, Dest, Ptr, Val1, Val2, 467 Size, SuccessOrder, llvm::AtomicOrdering::Monotonic, Scope); 468 CGF.Builder.CreateBr(ContBB); 469 470 if (AcquireBB) { 471 CGF.Builder.SetInsertPoint(AcquireBB); 472 emitAtomicCmpXchg(CGF, E, IsWeak, Dest, Ptr, Val1, Val2, 473 Size, SuccessOrder, llvm::AtomicOrdering::Acquire, Scope); 474 CGF.Builder.CreateBr(ContBB); 475 SI->addCase(CGF.Builder.getInt32((int)llvm::AtomicOrderingCABI::consume), 476 AcquireBB); 477 SI->addCase(CGF.Builder.getInt32((int)llvm::AtomicOrderingCABI::acquire), 478 AcquireBB); 479 } 480 if (SeqCstBB) { 481 CGF.Builder.SetInsertPoint(SeqCstBB); 482 emitAtomicCmpXchg(CGF, E, IsWeak, Dest, Ptr, Val1, Val2, Size, SuccessOrder, 483 llvm::AtomicOrdering::SequentiallyConsistent, Scope); 484 CGF.Builder.CreateBr(ContBB); 485 SI->addCase(CGF.Builder.getInt32((int)llvm::AtomicOrderingCABI::seq_cst), 486 SeqCstBB); 487 } 488 489 CGF.Builder.SetInsertPoint(ContBB); 490 } 491 492 /// Duplicate the atomic min/max operation in conventional IR for the builtin 493 /// variants that return the new rather than the original value. 494 static llvm::Value *EmitPostAtomicMinMax(CGBuilderTy &Builder, 495 AtomicExpr::AtomicOp Op, 496 bool IsSigned, 497 llvm::Value *OldVal, 498 llvm::Value *RHS) { 499 llvm::CmpInst::Predicate Pred; 500 switch (Op) { 501 default: 502 llvm_unreachable("Unexpected min/max operation"); 503 case AtomicExpr::AO__atomic_max_fetch: 504 Pred = IsSigned ? llvm::CmpInst::ICMP_SGT : llvm::CmpInst::ICMP_UGT; 505 break; 506 case AtomicExpr::AO__atomic_min_fetch: 507 Pred = IsSigned ? llvm::CmpInst::ICMP_SLT : llvm::CmpInst::ICMP_ULT; 508 break; 509 } 510 llvm::Value *Cmp = Builder.CreateICmp(Pred, OldVal, RHS, "tst"); 511 return Builder.CreateSelect(Cmp, OldVal, RHS, "newval"); 512 } 513 514 static void EmitAtomicOp(CodeGenFunction &CGF, AtomicExpr *E, Address Dest, 515 Address Ptr, Address Val1, Address Val2, 516 llvm::Value *IsWeak, llvm::Value *FailureOrder, 517 uint64_t Size, llvm::AtomicOrdering Order, 518 llvm::SyncScope::ID Scope) { 519 llvm::AtomicRMWInst::BinOp Op = llvm::AtomicRMWInst::Add; 520 bool PostOpMinMax = false; 521 unsigned PostOp = 0; 522 523 switch (E->getOp()) { 524 case AtomicExpr::AO__c11_atomic_init: 525 case AtomicExpr::AO__opencl_atomic_init: 526 llvm_unreachable("Already handled!"); 527 528 case AtomicExpr::AO__c11_atomic_compare_exchange_strong: 529 case AtomicExpr::AO__opencl_atomic_compare_exchange_strong: 530 emitAtomicCmpXchgFailureSet(CGF, E, false, Dest, Ptr, Val1, Val2, 531 FailureOrder, Size, Order, Scope); 532 return; 533 case AtomicExpr::AO__c11_atomic_compare_exchange_weak: 534 case AtomicExpr::AO__opencl_atomic_compare_exchange_weak: 535 emitAtomicCmpXchgFailureSet(CGF, E, true, Dest, Ptr, Val1, Val2, 536 FailureOrder, Size, Order, Scope); 537 return; 538 case AtomicExpr::AO__atomic_compare_exchange: 539 case AtomicExpr::AO__atomic_compare_exchange_n: { 540 if (llvm::ConstantInt *IsWeakC = dyn_cast<llvm::ConstantInt>(IsWeak)) { 541 emitAtomicCmpXchgFailureSet(CGF, E, IsWeakC->getZExtValue(), Dest, Ptr, 542 Val1, Val2, FailureOrder, Size, Order, Scope); 543 } else { 544 // Create all the relevant BB's 545 llvm::BasicBlock *StrongBB = 546 CGF.createBasicBlock("cmpxchg.strong", CGF.CurFn); 547 llvm::BasicBlock *WeakBB = CGF.createBasicBlock("cmxchg.weak", CGF.CurFn); 548 llvm::BasicBlock *ContBB = 549 CGF.createBasicBlock("cmpxchg.continue", CGF.CurFn); 550 551 llvm::SwitchInst *SI = CGF.Builder.CreateSwitch(IsWeak, WeakBB); 552 SI->addCase(CGF.Builder.getInt1(false), StrongBB); 553 554 CGF.Builder.SetInsertPoint(StrongBB); 555 emitAtomicCmpXchgFailureSet(CGF, E, false, Dest, Ptr, Val1, Val2, 556 FailureOrder, Size, Order, Scope); 557 CGF.Builder.CreateBr(ContBB); 558 559 CGF.Builder.SetInsertPoint(WeakBB); 560 emitAtomicCmpXchgFailureSet(CGF, E, true, Dest, Ptr, Val1, Val2, 561 FailureOrder, Size, Order, Scope); 562 CGF.Builder.CreateBr(ContBB); 563 564 CGF.Builder.SetInsertPoint(ContBB); 565 } 566 return; 567 } 568 case AtomicExpr::AO__c11_atomic_load: 569 case AtomicExpr::AO__opencl_atomic_load: 570 case AtomicExpr::AO__atomic_load_n: 571 case AtomicExpr::AO__atomic_load: { 572 llvm::LoadInst *Load = CGF.Builder.CreateLoad(Ptr); 573 Load->setAtomic(Order, Scope); 574 Load->setVolatile(E->isVolatile()); 575 CGF.Builder.CreateStore(Load, Dest); 576 return; 577 } 578 579 case AtomicExpr::AO__c11_atomic_store: 580 case AtomicExpr::AO__opencl_atomic_store: 581 case AtomicExpr::AO__atomic_store: 582 case AtomicExpr::AO__atomic_store_n: { 583 llvm::Value *LoadVal1 = CGF.Builder.CreateLoad(Val1); 584 llvm::StoreInst *Store = CGF.Builder.CreateStore(LoadVal1, Ptr); 585 Store->setAtomic(Order, Scope); 586 Store->setVolatile(E->isVolatile()); 587 return; 588 } 589 590 case AtomicExpr::AO__c11_atomic_exchange: 591 case AtomicExpr::AO__opencl_atomic_exchange: 592 case AtomicExpr::AO__atomic_exchange_n: 593 case AtomicExpr::AO__atomic_exchange: 594 Op = llvm::AtomicRMWInst::Xchg; 595 break; 596 597 case AtomicExpr::AO__atomic_add_fetch: 598 PostOp = llvm::Instruction::Add; 599 LLVM_FALLTHROUGH; 600 case AtomicExpr::AO__c11_atomic_fetch_add: 601 case AtomicExpr::AO__opencl_atomic_fetch_add: 602 case AtomicExpr::AO__atomic_fetch_add: 603 Op = llvm::AtomicRMWInst::Add; 604 break; 605 606 case AtomicExpr::AO__atomic_sub_fetch: 607 PostOp = llvm::Instruction::Sub; 608 LLVM_FALLTHROUGH; 609 case AtomicExpr::AO__c11_atomic_fetch_sub: 610 case AtomicExpr::AO__opencl_atomic_fetch_sub: 611 case AtomicExpr::AO__atomic_fetch_sub: 612 Op = llvm::AtomicRMWInst::Sub; 613 break; 614 615 case AtomicExpr::AO__atomic_min_fetch: 616 PostOpMinMax = true; 617 LLVM_FALLTHROUGH; 618 case AtomicExpr::AO__c11_atomic_fetch_min: 619 case AtomicExpr::AO__opencl_atomic_fetch_min: 620 case AtomicExpr::AO__atomic_fetch_min: 621 Op = E->getValueType()->isSignedIntegerType() ? llvm::AtomicRMWInst::Min 622 : llvm::AtomicRMWInst::UMin; 623 break; 624 625 case AtomicExpr::AO__atomic_max_fetch: 626 PostOpMinMax = true; 627 LLVM_FALLTHROUGH; 628 case AtomicExpr::AO__c11_atomic_fetch_max: 629 case AtomicExpr::AO__opencl_atomic_fetch_max: 630 case AtomicExpr::AO__atomic_fetch_max: 631 Op = E->getValueType()->isSignedIntegerType() ? llvm::AtomicRMWInst::Max 632 : llvm::AtomicRMWInst::UMax; 633 break; 634 635 case AtomicExpr::AO__atomic_and_fetch: 636 PostOp = llvm::Instruction::And; 637 LLVM_FALLTHROUGH; 638 case AtomicExpr::AO__c11_atomic_fetch_and: 639 case AtomicExpr::AO__opencl_atomic_fetch_and: 640 case AtomicExpr::AO__atomic_fetch_and: 641 Op = llvm::AtomicRMWInst::And; 642 break; 643 644 case AtomicExpr::AO__atomic_or_fetch: 645 PostOp = llvm::Instruction::Or; 646 LLVM_FALLTHROUGH; 647 case AtomicExpr::AO__c11_atomic_fetch_or: 648 case AtomicExpr::AO__opencl_atomic_fetch_or: 649 case AtomicExpr::AO__atomic_fetch_or: 650 Op = llvm::AtomicRMWInst::Or; 651 break; 652 653 case AtomicExpr::AO__atomic_xor_fetch: 654 PostOp = llvm::Instruction::Xor; 655 LLVM_FALLTHROUGH; 656 case AtomicExpr::AO__c11_atomic_fetch_xor: 657 case AtomicExpr::AO__opencl_atomic_fetch_xor: 658 case AtomicExpr::AO__atomic_fetch_xor: 659 Op = llvm::AtomicRMWInst::Xor; 660 break; 661 662 case AtomicExpr::AO__atomic_nand_fetch: 663 PostOp = llvm::Instruction::And; // the NOT is special cased below 664 LLVM_FALLTHROUGH; 665 case AtomicExpr::AO__atomic_fetch_nand: 666 Op = llvm::AtomicRMWInst::Nand; 667 break; 668 } 669 670 llvm::Value *LoadVal1 = CGF.Builder.CreateLoad(Val1); 671 llvm::AtomicRMWInst *RMWI = 672 CGF.Builder.CreateAtomicRMW(Op, Ptr.getPointer(), LoadVal1, Order, Scope); 673 RMWI->setVolatile(E->isVolatile()); 674 675 // For __atomic_*_fetch operations, perform the operation again to 676 // determine the value which was written. 677 llvm::Value *Result = RMWI; 678 if (PostOpMinMax) 679 Result = EmitPostAtomicMinMax(CGF.Builder, E->getOp(), 680 E->getValueType()->isSignedIntegerType(), 681 RMWI, LoadVal1); 682 else if (PostOp) 683 Result = CGF.Builder.CreateBinOp((llvm::Instruction::BinaryOps)PostOp, RMWI, 684 LoadVal1); 685 if (E->getOp() == AtomicExpr::AO__atomic_nand_fetch) 686 Result = CGF.Builder.CreateNot(Result); 687 CGF.Builder.CreateStore(Result, Dest); 688 } 689 690 // This function emits any expression (scalar, complex, or aggregate) 691 // into a temporary alloca. 692 static Address 693 EmitValToTemp(CodeGenFunction &CGF, Expr *E) { 694 Address DeclPtr = CGF.CreateMemTemp(E->getType(), ".atomictmp"); 695 CGF.EmitAnyExprToMem(E, DeclPtr, E->getType().getQualifiers(), 696 /*Init*/ true); 697 return DeclPtr; 698 } 699 700 static void EmitAtomicOp(CodeGenFunction &CGF, AtomicExpr *Expr, Address Dest, 701 Address Ptr, Address Val1, Address Val2, 702 llvm::Value *IsWeak, llvm::Value *FailureOrder, 703 uint64_t Size, llvm::AtomicOrdering Order, 704 llvm::Value *Scope) { 705 auto ScopeModel = Expr->getScopeModel(); 706 707 // LLVM atomic instructions always have synch scope. If clang atomic 708 // expression has no scope operand, use default LLVM synch scope. 709 if (!ScopeModel) { 710 EmitAtomicOp(CGF, Expr, Dest, Ptr, Val1, Val2, IsWeak, FailureOrder, Size, 711 Order, CGF.CGM.getLLVMContext().getOrInsertSyncScopeID("")); 712 return; 713 } 714 715 // Handle constant scope. 716 if (auto SC = dyn_cast<llvm::ConstantInt>(Scope)) { 717 auto SCID = CGF.getTargetHooks().getLLVMSyncScopeID( 718 CGF.CGM.getLangOpts(), ScopeModel->map(SC->getZExtValue()), 719 Order, CGF.CGM.getLLVMContext()); 720 EmitAtomicOp(CGF, Expr, Dest, Ptr, Val1, Val2, IsWeak, FailureOrder, Size, 721 Order, SCID); 722 return; 723 } 724 725 // Handle non-constant scope. 726 auto &Builder = CGF.Builder; 727 auto Scopes = ScopeModel->getRuntimeValues(); 728 llvm::DenseMap<unsigned, llvm::BasicBlock *> BB; 729 for (auto S : Scopes) 730 BB[S] = CGF.createBasicBlock(getAsString(ScopeModel->map(S)), CGF.CurFn); 731 732 llvm::BasicBlock *ContBB = 733 CGF.createBasicBlock("atomic.scope.continue", CGF.CurFn); 734 735 auto *SC = Builder.CreateIntCast(Scope, Builder.getInt32Ty(), false); 736 // If unsupported synch scope is encountered at run time, assume a fallback 737 // synch scope value. 738 auto FallBack = ScopeModel->getFallBackValue(); 739 llvm::SwitchInst *SI = Builder.CreateSwitch(SC, BB[FallBack]); 740 for (auto S : Scopes) { 741 auto *B = BB[S]; 742 if (S != FallBack) 743 SI->addCase(Builder.getInt32(S), B); 744 745 Builder.SetInsertPoint(B); 746 EmitAtomicOp(CGF, Expr, Dest, Ptr, Val1, Val2, IsWeak, FailureOrder, Size, 747 Order, 748 CGF.getTargetHooks().getLLVMSyncScopeID(CGF.CGM.getLangOpts(), 749 ScopeModel->map(S), 750 Order, 751 CGF.getLLVMContext())); 752 Builder.CreateBr(ContBB); 753 } 754 755 Builder.SetInsertPoint(ContBB); 756 } 757 758 static void 759 AddDirectArgument(CodeGenFunction &CGF, CallArgList &Args, 760 bool UseOptimizedLibcall, llvm::Value *Val, QualType ValTy, 761 SourceLocation Loc, CharUnits SizeInChars) { 762 if (UseOptimizedLibcall) { 763 // Load value and pass it to the function directly. 764 CharUnits Align = CGF.getContext().getTypeAlignInChars(ValTy); 765 int64_t SizeInBits = CGF.getContext().toBits(SizeInChars); 766 ValTy = 767 CGF.getContext().getIntTypeForBitwidth(SizeInBits, /*Signed=*/false); 768 llvm::Type *IPtrTy = llvm::IntegerType::get(CGF.getLLVMContext(), 769 SizeInBits)->getPointerTo(); 770 Address Ptr = Address(CGF.Builder.CreateBitCast(Val, IPtrTy), Align); 771 Val = CGF.EmitLoadOfScalar(Ptr, false, 772 CGF.getContext().getPointerType(ValTy), 773 Loc); 774 // Coerce the value into an appropriately sized integer type. 775 Args.add(RValue::get(Val), ValTy); 776 } else { 777 // Non-optimized functions always take a reference. 778 Args.add(RValue::get(CGF.EmitCastToVoidPtr(Val)), 779 CGF.getContext().VoidPtrTy); 780 } 781 } 782 783 RValue CodeGenFunction::EmitAtomicExpr(AtomicExpr *E) { 784 QualType AtomicTy = E->getPtr()->getType()->getPointeeType(); 785 QualType MemTy = AtomicTy; 786 if (const AtomicType *AT = AtomicTy->getAs<AtomicType>()) 787 MemTy = AT->getValueType(); 788 llvm::Value *IsWeak = nullptr, *OrderFail = nullptr; 789 790 Address Val1 = Address::invalid(); 791 Address Val2 = Address::invalid(); 792 Address Dest = Address::invalid(); 793 Address Ptr = EmitPointerWithAlignment(E->getPtr()); 794 795 if (E->getOp() == AtomicExpr::AO__c11_atomic_init || 796 E->getOp() == AtomicExpr::AO__opencl_atomic_init) { 797 LValue lvalue = MakeAddrLValue(Ptr, AtomicTy); 798 EmitAtomicInit(E->getVal1(), lvalue); 799 return RValue::get(nullptr); 800 } 801 802 CharUnits sizeChars, alignChars; 803 std::tie(sizeChars, alignChars) = getContext().getTypeInfoInChars(AtomicTy); 804 uint64_t Size = sizeChars.getQuantity(); 805 unsigned MaxInlineWidthInBits = getTarget().getMaxAtomicInlineWidth(); 806 807 bool Oversized = getContext().toBits(sizeChars) > MaxInlineWidthInBits; 808 bool Misaligned = (Ptr.getAlignment() % sizeChars) != 0; 809 bool UseLibcall = Misaligned | Oversized; 810 811 if (UseLibcall) { 812 CGM.getDiags().Report(E->getBeginLoc(), diag::warn_atomic_op_misaligned) 813 << !Oversized; 814 } 815 816 llvm::Value *Order = EmitScalarExpr(E->getOrder()); 817 llvm::Value *Scope = 818 E->getScopeModel() ? EmitScalarExpr(E->getScope()) : nullptr; 819 820 switch (E->getOp()) { 821 case AtomicExpr::AO__c11_atomic_init: 822 case AtomicExpr::AO__opencl_atomic_init: 823 llvm_unreachable("Already handled above with EmitAtomicInit!"); 824 825 case AtomicExpr::AO__c11_atomic_load: 826 case AtomicExpr::AO__opencl_atomic_load: 827 case AtomicExpr::AO__atomic_load_n: 828 break; 829 830 case AtomicExpr::AO__atomic_load: 831 Dest = EmitPointerWithAlignment(E->getVal1()); 832 break; 833 834 case AtomicExpr::AO__atomic_store: 835 Val1 = EmitPointerWithAlignment(E->getVal1()); 836 break; 837 838 case AtomicExpr::AO__atomic_exchange: 839 Val1 = EmitPointerWithAlignment(E->getVal1()); 840 Dest = EmitPointerWithAlignment(E->getVal2()); 841 break; 842 843 case AtomicExpr::AO__c11_atomic_compare_exchange_strong: 844 case AtomicExpr::AO__c11_atomic_compare_exchange_weak: 845 case AtomicExpr::AO__opencl_atomic_compare_exchange_strong: 846 case AtomicExpr::AO__opencl_atomic_compare_exchange_weak: 847 case AtomicExpr::AO__atomic_compare_exchange_n: 848 case AtomicExpr::AO__atomic_compare_exchange: 849 Val1 = EmitPointerWithAlignment(E->getVal1()); 850 if (E->getOp() == AtomicExpr::AO__atomic_compare_exchange) 851 Val2 = EmitPointerWithAlignment(E->getVal2()); 852 else 853 Val2 = EmitValToTemp(*this, E->getVal2()); 854 OrderFail = EmitScalarExpr(E->getOrderFail()); 855 if (E->getOp() == AtomicExpr::AO__atomic_compare_exchange_n || 856 E->getOp() == AtomicExpr::AO__atomic_compare_exchange) 857 IsWeak = EmitScalarExpr(E->getWeak()); 858 break; 859 860 case AtomicExpr::AO__c11_atomic_fetch_add: 861 case AtomicExpr::AO__c11_atomic_fetch_sub: 862 case AtomicExpr::AO__opencl_atomic_fetch_add: 863 case AtomicExpr::AO__opencl_atomic_fetch_sub: 864 if (MemTy->isPointerType()) { 865 // For pointer arithmetic, we're required to do a bit of math: 866 // adding 1 to an int* is not the same as adding 1 to a uintptr_t. 867 // ... but only for the C11 builtins. The GNU builtins expect the 868 // user to multiply by sizeof(T). 869 QualType Val1Ty = E->getVal1()->getType(); 870 llvm::Value *Val1Scalar = EmitScalarExpr(E->getVal1()); 871 CharUnits PointeeIncAmt = 872 getContext().getTypeSizeInChars(MemTy->getPointeeType()); 873 Val1Scalar = Builder.CreateMul(Val1Scalar, CGM.getSize(PointeeIncAmt)); 874 auto Temp = CreateMemTemp(Val1Ty, ".atomictmp"); 875 Val1 = Temp; 876 EmitStoreOfScalar(Val1Scalar, MakeAddrLValue(Temp, Val1Ty)); 877 break; 878 } 879 LLVM_FALLTHROUGH; 880 case AtomicExpr::AO__atomic_fetch_add: 881 case AtomicExpr::AO__atomic_fetch_sub: 882 case AtomicExpr::AO__atomic_add_fetch: 883 case AtomicExpr::AO__atomic_sub_fetch: 884 case AtomicExpr::AO__c11_atomic_store: 885 case AtomicExpr::AO__c11_atomic_exchange: 886 case AtomicExpr::AO__opencl_atomic_store: 887 case AtomicExpr::AO__opencl_atomic_exchange: 888 case AtomicExpr::AO__atomic_store_n: 889 case AtomicExpr::AO__atomic_exchange_n: 890 case AtomicExpr::AO__c11_atomic_fetch_and: 891 case AtomicExpr::AO__c11_atomic_fetch_or: 892 case AtomicExpr::AO__c11_atomic_fetch_xor: 893 case AtomicExpr::AO__c11_atomic_fetch_max: 894 case AtomicExpr::AO__c11_atomic_fetch_min: 895 case AtomicExpr::AO__opencl_atomic_fetch_and: 896 case AtomicExpr::AO__opencl_atomic_fetch_or: 897 case AtomicExpr::AO__opencl_atomic_fetch_xor: 898 case AtomicExpr::AO__opencl_atomic_fetch_min: 899 case AtomicExpr::AO__opencl_atomic_fetch_max: 900 case AtomicExpr::AO__atomic_fetch_and: 901 case AtomicExpr::AO__atomic_fetch_or: 902 case AtomicExpr::AO__atomic_fetch_xor: 903 case AtomicExpr::AO__atomic_fetch_nand: 904 case AtomicExpr::AO__atomic_and_fetch: 905 case AtomicExpr::AO__atomic_or_fetch: 906 case AtomicExpr::AO__atomic_xor_fetch: 907 case AtomicExpr::AO__atomic_nand_fetch: 908 case AtomicExpr::AO__atomic_max_fetch: 909 case AtomicExpr::AO__atomic_min_fetch: 910 case AtomicExpr::AO__atomic_fetch_max: 911 case AtomicExpr::AO__atomic_fetch_min: 912 Val1 = EmitValToTemp(*this, E->getVal1()); 913 break; 914 } 915 916 QualType RValTy = E->getType().getUnqualifiedType(); 917 918 // The inlined atomics only function on iN types, where N is a power of 2. We 919 // need to make sure (via temporaries if necessary) that all incoming values 920 // are compatible. 921 LValue AtomicVal = MakeAddrLValue(Ptr, AtomicTy); 922 AtomicInfo Atomics(*this, AtomicVal); 923 924 Ptr = Atomics.emitCastToAtomicIntPointer(Ptr); 925 if (Val1.isValid()) Val1 = Atomics.convertToAtomicIntPointer(Val1); 926 if (Val2.isValid()) Val2 = Atomics.convertToAtomicIntPointer(Val2); 927 if (Dest.isValid()) 928 Dest = Atomics.emitCastToAtomicIntPointer(Dest); 929 else if (E->isCmpXChg()) 930 Dest = CreateMemTemp(RValTy, "cmpxchg.bool"); 931 else if (!RValTy->isVoidType()) 932 Dest = Atomics.emitCastToAtomicIntPointer(Atomics.CreateTempAlloca()); 933 934 // Use a library call. See: http://gcc.gnu.org/wiki/Atomic/GCCMM/LIbrary . 935 if (UseLibcall) { 936 bool UseOptimizedLibcall = false; 937 switch (E->getOp()) { 938 case AtomicExpr::AO__c11_atomic_init: 939 case AtomicExpr::AO__opencl_atomic_init: 940 llvm_unreachable("Already handled above with EmitAtomicInit!"); 941 942 case AtomicExpr::AO__c11_atomic_fetch_add: 943 case AtomicExpr::AO__opencl_atomic_fetch_add: 944 case AtomicExpr::AO__atomic_fetch_add: 945 case AtomicExpr::AO__c11_atomic_fetch_and: 946 case AtomicExpr::AO__opencl_atomic_fetch_and: 947 case AtomicExpr::AO__atomic_fetch_and: 948 case AtomicExpr::AO__c11_atomic_fetch_or: 949 case AtomicExpr::AO__opencl_atomic_fetch_or: 950 case AtomicExpr::AO__atomic_fetch_or: 951 case AtomicExpr::AO__atomic_fetch_nand: 952 case AtomicExpr::AO__c11_atomic_fetch_sub: 953 case AtomicExpr::AO__opencl_atomic_fetch_sub: 954 case AtomicExpr::AO__atomic_fetch_sub: 955 case AtomicExpr::AO__c11_atomic_fetch_xor: 956 case AtomicExpr::AO__opencl_atomic_fetch_xor: 957 case AtomicExpr::AO__opencl_atomic_fetch_min: 958 case AtomicExpr::AO__opencl_atomic_fetch_max: 959 case AtomicExpr::AO__atomic_fetch_xor: 960 case AtomicExpr::AO__c11_atomic_fetch_max: 961 case AtomicExpr::AO__c11_atomic_fetch_min: 962 case AtomicExpr::AO__atomic_add_fetch: 963 case AtomicExpr::AO__atomic_and_fetch: 964 case AtomicExpr::AO__atomic_nand_fetch: 965 case AtomicExpr::AO__atomic_or_fetch: 966 case AtomicExpr::AO__atomic_sub_fetch: 967 case AtomicExpr::AO__atomic_xor_fetch: 968 case AtomicExpr::AO__atomic_fetch_max: 969 case AtomicExpr::AO__atomic_fetch_min: 970 case AtomicExpr::AO__atomic_max_fetch: 971 case AtomicExpr::AO__atomic_min_fetch: 972 // For these, only library calls for certain sizes exist. 973 UseOptimizedLibcall = true; 974 break; 975 976 case AtomicExpr::AO__atomic_load: 977 case AtomicExpr::AO__atomic_store: 978 case AtomicExpr::AO__atomic_exchange: 979 case AtomicExpr::AO__atomic_compare_exchange: 980 // Use the generic version if we don't know that the operand will be 981 // suitably aligned for the optimized version. 982 if (Misaligned) 983 break; 984 LLVM_FALLTHROUGH; 985 case AtomicExpr::AO__c11_atomic_load: 986 case AtomicExpr::AO__c11_atomic_store: 987 case AtomicExpr::AO__c11_atomic_exchange: 988 case AtomicExpr::AO__c11_atomic_compare_exchange_weak: 989 case AtomicExpr::AO__c11_atomic_compare_exchange_strong: 990 case AtomicExpr::AO__opencl_atomic_load: 991 case AtomicExpr::AO__opencl_atomic_store: 992 case AtomicExpr::AO__opencl_atomic_exchange: 993 case AtomicExpr::AO__opencl_atomic_compare_exchange_weak: 994 case AtomicExpr::AO__opencl_atomic_compare_exchange_strong: 995 case AtomicExpr::AO__atomic_load_n: 996 case AtomicExpr::AO__atomic_store_n: 997 case AtomicExpr::AO__atomic_exchange_n: 998 case AtomicExpr::AO__atomic_compare_exchange_n: 999 // Only use optimized library calls for sizes for which they exist. 1000 // FIXME: Size == 16 optimized library functions exist too. 1001 if (Size == 1 || Size == 2 || Size == 4 || Size == 8) 1002 UseOptimizedLibcall = true; 1003 break; 1004 } 1005 1006 CallArgList Args; 1007 if (!UseOptimizedLibcall) { 1008 // For non-optimized library calls, the size is the first parameter 1009 Args.add(RValue::get(llvm::ConstantInt::get(SizeTy, Size)), 1010 getContext().getSizeType()); 1011 } 1012 // Atomic address is the first or second parameter 1013 // The OpenCL atomic library functions only accept pointer arguments to 1014 // generic address space. 1015 auto CastToGenericAddrSpace = [&](llvm::Value *V, QualType PT) { 1016 if (!E->isOpenCL()) 1017 return V; 1018 auto AS = PT->castAs<PointerType>()->getPointeeType().getAddressSpace(); 1019 if (AS == LangAS::opencl_generic) 1020 return V; 1021 auto DestAS = getContext().getTargetAddressSpace(LangAS::opencl_generic); 1022 auto T = V->getType(); 1023 auto *DestType = T->getPointerElementType()->getPointerTo(DestAS); 1024 1025 return getTargetHooks().performAddrSpaceCast( 1026 *this, V, AS, LangAS::opencl_generic, DestType, false); 1027 }; 1028 1029 Args.add(RValue::get(CastToGenericAddrSpace( 1030 EmitCastToVoidPtr(Ptr.getPointer()), E->getPtr()->getType())), 1031 getContext().VoidPtrTy); 1032 1033 std::string LibCallName; 1034 QualType LoweredMemTy = 1035 MemTy->isPointerType() ? getContext().getIntPtrType() : MemTy; 1036 QualType RetTy; 1037 bool HaveRetTy = false; 1038 llvm::Instruction::BinaryOps PostOp = (llvm::Instruction::BinaryOps)0; 1039 bool PostOpMinMax = false; 1040 switch (E->getOp()) { 1041 case AtomicExpr::AO__c11_atomic_init: 1042 case AtomicExpr::AO__opencl_atomic_init: 1043 llvm_unreachable("Already handled!"); 1044 1045 // There is only one libcall for compare an exchange, because there is no 1046 // optimisation benefit possible from a libcall version of a weak compare 1047 // and exchange. 1048 // bool __atomic_compare_exchange(size_t size, void *mem, void *expected, 1049 // void *desired, int success, int failure) 1050 // bool __atomic_compare_exchange_N(T *mem, T *expected, T desired, 1051 // int success, int failure) 1052 case AtomicExpr::AO__c11_atomic_compare_exchange_weak: 1053 case AtomicExpr::AO__c11_atomic_compare_exchange_strong: 1054 case AtomicExpr::AO__opencl_atomic_compare_exchange_weak: 1055 case AtomicExpr::AO__opencl_atomic_compare_exchange_strong: 1056 case AtomicExpr::AO__atomic_compare_exchange: 1057 case AtomicExpr::AO__atomic_compare_exchange_n: 1058 LibCallName = "__atomic_compare_exchange"; 1059 RetTy = getContext().BoolTy; 1060 HaveRetTy = true; 1061 Args.add( 1062 RValue::get(CastToGenericAddrSpace( 1063 EmitCastToVoidPtr(Val1.getPointer()), E->getVal1()->getType())), 1064 getContext().VoidPtrTy); 1065 AddDirectArgument(*this, Args, UseOptimizedLibcall, Val2.getPointer(), 1066 MemTy, E->getExprLoc(), sizeChars); 1067 Args.add(RValue::get(Order), getContext().IntTy); 1068 Order = OrderFail; 1069 break; 1070 // void __atomic_exchange(size_t size, void *mem, void *val, void *return, 1071 // int order) 1072 // T __atomic_exchange_N(T *mem, T val, int order) 1073 case AtomicExpr::AO__c11_atomic_exchange: 1074 case AtomicExpr::AO__opencl_atomic_exchange: 1075 case AtomicExpr::AO__atomic_exchange_n: 1076 case AtomicExpr::AO__atomic_exchange: 1077 LibCallName = "__atomic_exchange"; 1078 AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(), 1079 MemTy, E->getExprLoc(), sizeChars); 1080 break; 1081 // void __atomic_store(size_t size, void *mem, void *val, int order) 1082 // void __atomic_store_N(T *mem, T val, int order) 1083 case AtomicExpr::AO__c11_atomic_store: 1084 case AtomicExpr::AO__opencl_atomic_store: 1085 case AtomicExpr::AO__atomic_store: 1086 case AtomicExpr::AO__atomic_store_n: 1087 LibCallName = "__atomic_store"; 1088 RetTy = getContext().VoidTy; 1089 HaveRetTy = true; 1090 AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(), 1091 MemTy, E->getExprLoc(), sizeChars); 1092 break; 1093 // void __atomic_load(size_t size, void *mem, void *return, int order) 1094 // T __atomic_load_N(T *mem, int order) 1095 case AtomicExpr::AO__c11_atomic_load: 1096 case AtomicExpr::AO__opencl_atomic_load: 1097 case AtomicExpr::AO__atomic_load: 1098 case AtomicExpr::AO__atomic_load_n: 1099 LibCallName = "__atomic_load"; 1100 break; 1101 // T __atomic_add_fetch_N(T *mem, T val, int order) 1102 // T __atomic_fetch_add_N(T *mem, T val, int order) 1103 case AtomicExpr::AO__atomic_add_fetch: 1104 PostOp = llvm::Instruction::Add; 1105 LLVM_FALLTHROUGH; 1106 case AtomicExpr::AO__c11_atomic_fetch_add: 1107 case AtomicExpr::AO__opencl_atomic_fetch_add: 1108 case AtomicExpr::AO__atomic_fetch_add: 1109 LibCallName = "__atomic_fetch_add"; 1110 AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(), 1111 LoweredMemTy, E->getExprLoc(), sizeChars); 1112 break; 1113 // T __atomic_and_fetch_N(T *mem, T val, int order) 1114 // T __atomic_fetch_and_N(T *mem, T val, int order) 1115 case AtomicExpr::AO__atomic_and_fetch: 1116 PostOp = llvm::Instruction::And; 1117 LLVM_FALLTHROUGH; 1118 case AtomicExpr::AO__c11_atomic_fetch_and: 1119 case AtomicExpr::AO__opencl_atomic_fetch_and: 1120 case AtomicExpr::AO__atomic_fetch_and: 1121 LibCallName = "__atomic_fetch_and"; 1122 AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(), 1123 MemTy, E->getExprLoc(), sizeChars); 1124 break; 1125 // T __atomic_or_fetch_N(T *mem, T val, int order) 1126 // T __atomic_fetch_or_N(T *mem, T val, int order) 1127 case AtomicExpr::AO__atomic_or_fetch: 1128 PostOp = llvm::Instruction::Or; 1129 LLVM_FALLTHROUGH; 1130 case AtomicExpr::AO__c11_atomic_fetch_or: 1131 case AtomicExpr::AO__opencl_atomic_fetch_or: 1132 case AtomicExpr::AO__atomic_fetch_or: 1133 LibCallName = "__atomic_fetch_or"; 1134 AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(), 1135 MemTy, E->getExprLoc(), sizeChars); 1136 break; 1137 // T __atomic_sub_fetch_N(T *mem, T val, int order) 1138 // T __atomic_fetch_sub_N(T *mem, T val, int order) 1139 case AtomicExpr::AO__atomic_sub_fetch: 1140 PostOp = llvm::Instruction::Sub; 1141 LLVM_FALLTHROUGH; 1142 case AtomicExpr::AO__c11_atomic_fetch_sub: 1143 case AtomicExpr::AO__opencl_atomic_fetch_sub: 1144 case AtomicExpr::AO__atomic_fetch_sub: 1145 LibCallName = "__atomic_fetch_sub"; 1146 AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(), 1147 LoweredMemTy, E->getExprLoc(), sizeChars); 1148 break; 1149 // T __atomic_xor_fetch_N(T *mem, T val, int order) 1150 // T __atomic_fetch_xor_N(T *mem, T val, int order) 1151 case AtomicExpr::AO__atomic_xor_fetch: 1152 PostOp = llvm::Instruction::Xor; 1153 LLVM_FALLTHROUGH; 1154 case AtomicExpr::AO__c11_atomic_fetch_xor: 1155 case AtomicExpr::AO__opencl_atomic_fetch_xor: 1156 case AtomicExpr::AO__atomic_fetch_xor: 1157 LibCallName = "__atomic_fetch_xor"; 1158 AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(), 1159 MemTy, E->getExprLoc(), sizeChars); 1160 break; 1161 case AtomicExpr::AO__atomic_min_fetch: 1162 PostOpMinMax = true; 1163 LLVM_FALLTHROUGH; 1164 case AtomicExpr::AO__c11_atomic_fetch_min: 1165 case AtomicExpr::AO__atomic_fetch_min: 1166 case AtomicExpr::AO__opencl_atomic_fetch_min: 1167 LibCallName = E->getValueType()->isSignedIntegerType() 1168 ? "__atomic_fetch_min" 1169 : "__atomic_fetch_umin"; 1170 AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(), 1171 LoweredMemTy, E->getExprLoc(), sizeChars); 1172 break; 1173 case AtomicExpr::AO__atomic_max_fetch: 1174 PostOpMinMax = true; 1175 LLVM_FALLTHROUGH; 1176 case AtomicExpr::AO__c11_atomic_fetch_max: 1177 case AtomicExpr::AO__atomic_fetch_max: 1178 case AtomicExpr::AO__opencl_atomic_fetch_max: 1179 LibCallName = E->getValueType()->isSignedIntegerType() 1180 ? "__atomic_fetch_max" 1181 : "__atomic_fetch_umax"; 1182 AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(), 1183 LoweredMemTy, E->getExprLoc(), sizeChars); 1184 break; 1185 // T __atomic_nand_fetch_N(T *mem, T val, int order) 1186 // T __atomic_fetch_nand_N(T *mem, T val, int order) 1187 case AtomicExpr::AO__atomic_nand_fetch: 1188 PostOp = llvm::Instruction::And; // the NOT is special cased below 1189 LLVM_FALLTHROUGH; 1190 case AtomicExpr::AO__atomic_fetch_nand: 1191 LibCallName = "__atomic_fetch_nand"; 1192 AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(), 1193 MemTy, E->getExprLoc(), sizeChars); 1194 break; 1195 } 1196 1197 if (E->isOpenCL()) { 1198 LibCallName = std::string("__opencl") + 1199 StringRef(LibCallName).drop_front(1).str(); 1200 1201 } 1202 // Optimized functions have the size in their name. 1203 if (UseOptimizedLibcall) 1204 LibCallName += "_" + llvm::utostr(Size); 1205 // By default, assume we return a value of the atomic type. 1206 if (!HaveRetTy) { 1207 if (UseOptimizedLibcall) { 1208 // Value is returned directly. 1209 // The function returns an appropriately sized integer type. 1210 RetTy = getContext().getIntTypeForBitwidth( 1211 getContext().toBits(sizeChars), /*Signed=*/false); 1212 } else { 1213 // Value is returned through parameter before the order. 1214 RetTy = getContext().VoidTy; 1215 Args.add(RValue::get(EmitCastToVoidPtr(Dest.getPointer())), 1216 getContext().VoidPtrTy); 1217 } 1218 } 1219 // order is always the last parameter 1220 Args.add(RValue::get(Order), 1221 getContext().IntTy); 1222 if (E->isOpenCL()) 1223 Args.add(RValue::get(Scope), getContext().IntTy); 1224 1225 // PostOp is only needed for the atomic_*_fetch operations, and 1226 // thus is only needed for and implemented in the 1227 // UseOptimizedLibcall codepath. 1228 assert(UseOptimizedLibcall || (!PostOp && !PostOpMinMax)); 1229 1230 RValue Res = emitAtomicLibcall(*this, LibCallName, RetTy, Args); 1231 // The value is returned directly from the libcall. 1232 if (E->isCmpXChg()) 1233 return Res; 1234 1235 // The value is returned directly for optimized libcalls but the expr 1236 // provided an out-param. 1237 if (UseOptimizedLibcall && Res.getScalarVal()) { 1238 llvm::Value *ResVal = Res.getScalarVal(); 1239 if (PostOpMinMax) { 1240 llvm::Value *LoadVal1 = Args[1].getRValue(*this).getScalarVal(); 1241 ResVal = EmitPostAtomicMinMax(Builder, E->getOp(), 1242 E->getValueType()->isSignedIntegerType(), 1243 ResVal, LoadVal1); 1244 } else if (PostOp) { 1245 llvm::Value *LoadVal1 = Args[1].getRValue(*this).getScalarVal(); 1246 ResVal = Builder.CreateBinOp(PostOp, ResVal, LoadVal1); 1247 } 1248 if (E->getOp() == AtomicExpr::AO__atomic_nand_fetch) 1249 ResVal = Builder.CreateNot(ResVal); 1250 1251 Builder.CreateStore( 1252 ResVal, 1253 Builder.CreateBitCast(Dest, ResVal->getType()->getPointerTo())); 1254 } 1255 1256 if (RValTy->isVoidType()) 1257 return RValue::get(nullptr); 1258 1259 return convertTempToRValue( 1260 Builder.CreateBitCast(Dest, ConvertTypeForMem(RValTy)->getPointerTo()), 1261 RValTy, E->getExprLoc()); 1262 } 1263 1264 bool IsStore = E->getOp() == AtomicExpr::AO__c11_atomic_store || 1265 E->getOp() == AtomicExpr::AO__opencl_atomic_store || 1266 E->getOp() == AtomicExpr::AO__atomic_store || 1267 E->getOp() == AtomicExpr::AO__atomic_store_n; 1268 bool IsLoad = E->getOp() == AtomicExpr::AO__c11_atomic_load || 1269 E->getOp() == AtomicExpr::AO__opencl_atomic_load || 1270 E->getOp() == AtomicExpr::AO__atomic_load || 1271 E->getOp() == AtomicExpr::AO__atomic_load_n; 1272 1273 if (isa<llvm::ConstantInt>(Order)) { 1274 auto ord = cast<llvm::ConstantInt>(Order)->getZExtValue(); 1275 // We should not ever get to a case where the ordering isn't a valid C ABI 1276 // value, but it's hard to enforce that in general. 1277 if (llvm::isValidAtomicOrderingCABI(ord)) 1278 switch ((llvm::AtomicOrderingCABI)ord) { 1279 case llvm::AtomicOrderingCABI::relaxed: 1280 EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size, 1281 llvm::AtomicOrdering::Monotonic, Scope); 1282 break; 1283 case llvm::AtomicOrderingCABI::consume: 1284 case llvm::AtomicOrderingCABI::acquire: 1285 if (IsStore) 1286 break; // Avoid crashing on code with undefined behavior 1287 EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size, 1288 llvm::AtomicOrdering::Acquire, Scope); 1289 break; 1290 case llvm::AtomicOrderingCABI::release: 1291 if (IsLoad) 1292 break; // Avoid crashing on code with undefined behavior 1293 EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size, 1294 llvm::AtomicOrdering::Release, Scope); 1295 break; 1296 case llvm::AtomicOrderingCABI::acq_rel: 1297 if (IsLoad || IsStore) 1298 break; // Avoid crashing on code with undefined behavior 1299 EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size, 1300 llvm::AtomicOrdering::AcquireRelease, Scope); 1301 break; 1302 case llvm::AtomicOrderingCABI::seq_cst: 1303 EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size, 1304 llvm::AtomicOrdering::SequentiallyConsistent, Scope); 1305 break; 1306 } 1307 if (RValTy->isVoidType()) 1308 return RValue::get(nullptr); 1309 1310 return convertTempToRValue( 1311 Builder.CreateBitCast(Dest, ConvertTypeForMem(RValTy)->getPointerTo( 1312 Dest.getAddressSpace())), 1313 RValTy, E->getExprLoc()); 1314 } 1315 1316 // Long case, when Order isn't obviously constant. 1317 1318 // Create all the relevant BB's 1319 llvm::BasicBlock *MonotonicBB = nullptr, *AcquireBB = nullptr, 1320 *ReleaseBB = nullptr, *AcqRelBB = nullptr, 1321 *SeqCstBB = nullptr; 1322 MonotonicBB = createBasicBlock("monotonic", CurFn); 1323 if (!IsStore) 1324 AcquireBB = createBasicBlock("acquire", CurFn); 1325 if (!IsLoad) 1326 ReleaseBB = createBasicBlock("release", CurFn); 1327 if (!IsLoad && !IsStore) 1328 AcqRelBB = createBasicBlock("acqrel", CurFn); 1329 SeqCstBB = createBasicBlock("seqcst", CurFn); 1330 llvm::BasicBlock *ContBB = createBasicBlock("atomic.continue", CurFn); 1331 1332 // Create the switch for the split 1333 // MonotonicBB is arbitrarily chosen as the default case; in practice, this 1334 // doesn't matter unless someone is crazy enough to use something that 1335 // doesn't fold to a constant for the ordering. 1336 Order = Builder.CreateIntCast(Order, Builder.getInt32Ty(), false); 1337 llvm::SwitchInst *SI = Builder.CreateSwitch(Order, MonotonicBB); 1338 1339 // Emit all the different atomics 1340 Builder.SetInsertPoint(MonotonicBB); 1341 EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size, 1342 llvm::AtomicOrdering::Monotonic, Scope); 1343 Builder.CreateBr(ContBB); 1344 if (!IsStore) { 1345 Builder.SetInsertPoint(AcquireBB); 1346 EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size, 1347 llvm::AtomicOrdering::Acquire, Scope); 1348 Builder.CreateBr(ContBB); 1349 SI->addCase(Builder.getInt32((int)llvm::AtomicOrderingCABI::consume), 1350 AcquireBB); 1351 SI->addCase(Builder.getInt32((int)llvm::AtomicOrderingCABI::acquire), 1352 AcquireBB); 1353 } 1354 if (!IsLoad) { 1355 Builder.SetInsertPoint(ReleaseBB); 1356 EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size, 1357 llvm::AtomicOrdering::Release, Scope); 1358 Builder.CreateBr(ContBB); 1359 SI->addCase(Builder.getInt32((int)llvm::AtomicOrderingCABI::release), 1360 ReleaseBB); 1361 } 1362 if (!IsLoad && !IsStore) { 1363 Builder.SetInsertPoint(AcqRelBB); 1364 EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size, 1365 llvm::AtomicOrdering::AcquireRelease, Scope); 1366 Builder.CreateBr(ContBB); 1367 SI->addCase(Builder.getInt32((int)llvm::AtomicOrderingCABI::acq_rel), 1368 AcqRelBB); 1369 } 1370 Builder.SetInsertPoint(SeqCstBB); 1371 EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size, 1372 llvm::AtomicOrdering::SequentiallyConsistent, Scope); 1373 Builder.CreateBr(ContBB); 1374 SI->addCase(Builder.getInt32((int)llvm::AtomicOrderingCABI::seq_cst), 1375 SeqCstBB); 1376 1377 // Cleanup and return 1378 Builder.SetInsertPoint(ContBB); 1379 if (RValTy->isVoidType()) 1380 return RValue::get(nullptr); 1381 1382 assert(Atomics.getValueSizeInBits() <= Atomics.getAtomicSizeInBits()); 1383 return convertTempToRValue( 1384 Builder.CreateBitCast(Dest, ConvertTypeForMem(RValTy)->getPointerTo( 1385 Dest.getAddressSpace())), 1386 RValTy, E->getExprLoc()); 1387 } 1388 1389 Address AtomicInfo::emitCastToAtomicIntPointer(Address addr) const { 1390 unsigned addrspace = 1391 cast<llvm::PointerType>(addr.getPointer()->getType())->getAddressSpace(); 1392 llvm::IntegerType *ty = 1393 llvm::IntegerType::get(CGF.getLLVMContext(), AtomicSizeInBits); 1394 return CGF.Builder.CreateBitCast(addr, ty->getPointerTo(addrspace)); 1395 } 1396 1397 Address AtomicInfo::convertToAtomicIntPointer(Address Addr) const { 1398 llvm::Type *Ty = Addr.getElementType(); 1399 uint64_t SourceSizeInBits = CGF.CGM.getDataLayout().getTypeSizeInBits(Ty); 1400 if (SourceSizeInBits != AtomicSizeInBits) { 1401 Address Tmp = CreateTempAlloca(); 1402 CGF.Builder.CreateMemCpy(Tmp, Addr, 1403 std::min(AtomicSizeInBits, SourceSizeInBits) / 8); 1404 Addr = Tmp; 1405 } 1406 1407 return emitCastToAtomicIntPointer(Addr); 1408 } 1409 1410 RValue AtomicInfo::convertAtomicTempToRValue(Address addr, 1411 AggValueSlot resultSlot, 1412 SourceLocation loc, 1413 bool asValue) const { 1414 if (LVal.isSimple()) { 1415 if (EvaluationKind == TEK_Aggregate) 1416 return resultSlot.asRValue(); 1417 1418 // Drill into the padding structure if we have one. 1419 if (hasPadding()) 1420 addr = CGF.Builder.CreateStructGEP(addr, 0); 1421 1422 // Otherwise, just convert the temporary to an r-value using the 1423 // normal conversion routine. 1424 return CGF.convertTempToRValue(addr, getValueType(), loc); 1425 } 1426 if (!asValue) 1427 // Get RValue from temp memory as atomic for non-simple lvalues 1428 return RValue::get(CGF.Builder.CreateLoad(addr)); 1429 if (LVal.isBitField()) 1430 return CGF.EmitLoadOfBitfieldLValue( 1431 LValue::MakeBitfield(addr, LVal.getBitFieldInfo(), LVal.getType(), 1432 LVal.getBaseInfo(), TBAAAccessInfo()), loc); 1433 if (LVal.isVectorElt()) 1434 return CGF.EmitLoadOfLValue( 1435 LValue::MakeVectorElt(addr, LVal.getVectorIdx(), LVal.getType(), 1436 LVal.getBaseInfo(), TBAAAccessInfo()), loc); 1437 assert(LVal.isExtVectorElt()); 1438 return CGF.EmitLoadOfExtVectorElementLValue(LValue::MakeExtVectorElt( 1439 addr, LVal.getExtVectorElts(), LVal.getType(), 1440 LVal.getBaseInfo(), TBAAAccessInfo())); 1441 } 1442 1443 RValue AtomicInfo::ConvertIntToValueOrAtomic(llvm::Value *IntVal, 1444 AggValueSlot ResultSlot, 1445 SourceLocation Loc, 1446 bool AsValue) const { 1447 // Try not to in some easy cases. 1448 assert(IntVal->getType()->isIntegerTy() && "Expected integer value"); 1449 if (getEvaluationKind() == TEK_Scalar && 1450 (((!LVal.isBitField() || 1451 LVal.getBitFieldInfo().Size == ValueSizeInBits) && 1452 !hasPadding()) || 1453 !AsValue)) { 1454 auto *ValTy = AsValue 1455 ? CGF.ConvertTypeForMem(ValueTy) 1456 : getAtomicAddress().getType()->getPointerElementType(); 1457 if (ValTy->isIntegerTy()) { 1458 assert(IntVal->getType() == ValTy && "Different integer types."); 1459 return RValue::get(CGF.EmitFromMemory(IntVal, ValueTy)); 1460 } else if (ValTy->isPointerTy()) 1461 return RValue::get(CGF.Builder.CreateIntToPtr(IntVal, ValTy)); 1462 else if (llvm::CastInst::isBitCastable(IntVal->getType(), ValTy)) 1463 return RValue::get(CGF.Builder.CreateBitCast(IntVal, ValTy)); 1464 } 1465 1466 // Create a temporary. This needs to be big enough to hold the 1467 // atomic integer. 1468 Address Temp = Address::invalid(); 1469 bool TempIsVolatile = false; 1470 if (AsValue && getEvaluationKind() == TEK_Aggregate) { 1471 assert(!ResultSlot.isIgnored()); 1472 Temp = ResultSlot.getAddress(); 1473 TempIsVolatile = ResultSlot.isVolatile(); 1474 } else { 1475 Temp = CreateTempAlloca(); 1476 } 1477 1478 // Slam the integer into the temporary. 1479 Address CastTemp = emitCastToAtomicIntPointer(Temp); 1480 CGF.Builder.CreateStore(IntVal, CastTemp) 1481 ->setVolatile(TempIsVolatile); 1482 1483 return convertAtomicTempToRValue(Temp, ResultSlot, Loc, AsValue); 1484 } 1485 1486 void AtomicInfo::EmitAtomicLoadLibcall(llvm::Value *AddForLoaded, 1487 llvm::AtomicOrdering AO, bool) { 1488 // void __atomic_load(size_t size, void *mem, void *return, int order); 1489 CallArgList Args; 1490 Args.add(RValue::get(getAtomicSizeValue()), CGF.getContext().getSizeType()); 1491 Args.add(RValue::get(CGF.EmitCastToVoidPtr(getAtomicPointer())), 1492 CGF.getContext().VoidPtrTy); 1493 Args.add(RValue::get(CGF.EmitCastToVoidPtr(AddForLoaded)), 1494 CGF.getContext().VoidPtrTy); 1495 Args.add( 1496 RValue::get(llvm::ConstantInt::get(CGF.IntTy, (int)llvm::toCABI(AO))), 1497 CGF.getContext().IntTy); 1498 emitAtomicLibcall(CGF, "__atomic_load", CGF.getContext().VoidTy, Args); 1499 } 1500 1501 llvm::Value *AtomicInfo::EmitAtomicLoadOp(llvm::AtomicOrdering AO, 1502 bool IsVolatile) { 1503 // Okay, we're doing this natively. 1504 Address Addr = getAtomicAddressAsAtomicIntPointer(); 1505 llvm::LoadInst *Load = CGF.Builder.CreateLoad(Addr, "atomic-load"); 1506 Load->setAtomic(AO); 1507 1508 // Other decoration. 1509 if (IsVolatile) 1510 Load->setVolatile(true); 1511 CGF.CGM.DecorateInstructionWithTBAA(Load, LVal.getTBAAInfo()); 1512 return Load; 1513 } 1514 1515 /// An LValue is a candidate for having its loads and stores be made atomic if 1516 /// we are operating under /volatile:ms *and* the LValue itself is volatile and 1517 /// performing such an operation can be performed without a libcall. 1518 bool CodeGenFunction::LValueIsSuitableForInlineAtomic(LValue LV) { 1519 if (!CGM.getCodeGenOpts().MSVolatile) return false; 1520 AtomicInfo AI(*this, LV); 1521 bool IsVolatile = LV.isVolatile() || hasVolatileMember(LV.getType()); 1522 // An atomic is inline if we don't need to use a libcall. 1523 bool AtomicIsInline = !AI.shouldUseLibcall(); 1524 // MSVC doesn't seem to do this for types wider than a pointer. 1525 if (getContext().getTypeSize(LV.getType()) > 1526 getContext().getTypeSize(getContext().getIntPtrType())) 1527 return false; 1528 return IsVolatile && AtomicIsInline; 1529 } 1530 1531 RValue CodeGenFunction::EmitAtomicLoad(LValue LV, SourceLocation SL, 1532 AggValueSlot Slot) { 1533 llvm::AtomicOrdering AO; 1534 bool IsVolatile = LV.isVolatileQualified(); 1535 if (LV.getType()->isAtomicType()) { 1536 AO = llvm::AtomicOrdering::SequentiallyConsistent; 1537 } else { 1538 AO = llvm::AtomicOrdering::Acquire; 1539 IsVolatile = true; 1540 } 1541 return EmitAtomicLoad(LV, SL, AO, IsVolatile, Slot); 1542 } 1543 1544 RValue AtomicInfo::EmitAtomicLoad(AggValueSlot ResultSlot, SourceLocation Loc, 1545 bool AsValue, llvm::AtomicOrdering AO, 1546 bool IsVolatile) { 1547 // Check whether we should use a library call. 1548 if (shouldUseLibcall()) { 1549 Address TempAddr = Address::invalid(); 1550 if (LVal.isSimple() && !ResultSlot.isIgnored()) { 1551 assert(getEvaluationKind() == TEK_Aggregate); 1552 TempAddr = ResultSlot.getAddress(); 1553 } else 1554 TempAddr = CreateTempAlloca(); 1555 1556 EmitAtomicLoadLibcall(TempAddr.getPointer(), AO, IsVolatile); 1557 1558 // Okay, turn that back into the original value or whole atomic (for 1559 // non-simple lvalues) type. 1560 return convertAtomicTempToRValue(TempAddr, ResultSlot, Loc, AsValue); 1561 } 1562 1563 // Okay, we're doing this natively. 1564 auto *Load = EmitAtomicLoadOp(AO, IsVolatile); 1565 1566 // If we're ignoring an aggregate return, don't do anything. 1567 if (getEvaluationKind() == TEK_Aggregate && ResultSlot.isIgnored()) 1568 return RValue::getAggregate(Address::invalid(), false); 1569 1570 // Okay, turn that back into the original value or atomic (for non-simple 1571 // lvalues) type. 1572 return ConvertIntToValueOrAtomic(Load, ResultSlot, Loc, AsValue); 1573 } 1574 1575 /// Emit a load from an l-value of atomic type. Note that the r-value 1576 /// we produce is an r-value of the atomic *value* type. 1577 RValue CodeGenFunction::EmitAtomicLoad(LValue src, SourceLocation loc, 1578 llvm::AtomicOrdering AO, bool IsVolatile, 1579 AggValueSlot resultSlot) { 1580 AtomicInfo Atomics(*this, src); 1581 return Atomics.EmitAtomicLoad(resultSlot, loc, /*AsValue=*/true, AO, 1582 IsVolatile); 1583 } 1584 1585 /// Copy an r-value into memory as part of storing to an atomic type. 1586 /// This needs to create a bit-pattern suitable for atomic operations. 1587 void AtomicInfo::emitCopyIntoMemory(RValue rvalue) const { 1588 assert(LVal.isSimple()); 1589 // If we have an r-value, the rvalue should be of the atomic type, 1590 // which means that the caller is responsible for having zeroed 1591 // any padding. Just do an aggregate copy of that type. 1592 if (rvalue.isAggregate()) { 1593 LValue Dest = CGF.MakeAddrLValue(getAtomicAddress(), getAtomicType()); 1594 LValue Src = CGF.MakeAddrLValue(rvalue.getAggregateAddress(), 1595 getAtomicType()); 1596 bool IsVolatile = rvalue.isVolatileQualified() || 1597 LVal.isVolatileQualified(); 1598 CGF.EmitAggregateCopy(Dest, Src, getAtomicType(), 1599 AggValueSlot::DoesNotOverlap, IsVolatile); 1600 return; 1601 } 1602 1603 // Okay, otherwise we're copying stuff. 1604 1605 // Zero out the buffer if necessary. 1606 emitMemSetZeroIfNecessary(); 1607 1608 // Drill past the padding if present. 1609 LValue TempLVal = projectValue(); 1610 1611 // Okay, store the rvalue in. 1612 if (rvalue.isScalar()) { 1613 CGF.EmitStoreOfScalar(rvalue.getScalarVal(), TempLVal, /*init*/ true); 1614 } else { 1615 CGF.EmitStoreOfComplex(rvalue.getComplexVal(), TempLVal, /*init*/ true); 1616 } 1617 } 1618 1619 1620 /// Materialize an r-value into memory for the purposes of storing it 1621 /// to an atomic type. 1622 Address AtomicInfo::materializeRValue(RValue rvalue) const { 1623 // Aggregate r-values are already in memory, and EmitAtomicStore 1624 // requires them to be values of the atomic type. 1625 if (rvalue.isAggregate()) 1626 return rvalue.getAggregateAddress(); 1627 1628 // Otherwise, make a temporary and materialize into it. 1629 LValue TempLV = CGF.MakeAddrLValue(CreateTempAlloca(), getAtomicType()); 1630 AtomicInfo Atomics(CGF, TempLV); 1631 Atomics.emitCopyIntoMemory(rvalue); 1632 return TempLV.getAddress(CGF); 1633 } 1634 1635 llvm::Value *AtomicInfo::convertRValueToInt(RValue RVal) const { 1636 // If we've got a scalar value of the right size, try to avoid going 1637 // through memory. 1638 if (RVal.isScalar() && (!hasPadding() || !LVal.isSimple())) { 1639 llvm::Value *Value = RVal.getScalarVal(); 1640 if (isa<llvm::IntegerType>(Value->getType())) 1641 return CGF.EmitToMemory(Value, ValueTy); 1642 else { 1643 llvm::IntegerType *InputIntTy = llvm::IntegerType::get( 1644 CGF.getLLVMContext(), 1645 LVal.isSimple() ? getValueSizeInBits() : getAtomicSizeInBits()); 1646 if (isa<llvm::PointerType>(Value->getType())) 1647 return CGF.Builder.CreatePtrToInt(Value, InputIntTy); 1648 else if (llvm::BitCastInst::isBitCastable(Value->getType(), InputIntTy)) 1649 return CGF.Builder.CreateBitCast(Value, InputIntTy); 1650 } 1651 } 1652 // Otherwise, we need to go through memory. 1653 // Put the r-value in memory. 1654 Address Addr = materializeRValue(RVal); 1655 1656 // Cast the temporary to the atomic int type and pull a value out. 1657 Addr = emitCastToAtomicIntPointer(Addr); 1658 return CGF.Builder.CreateLoad(Addr); 1659 } 1660 1661 std::pair<llvm::Value *, llvm::Value *> AtomicInfo::EmitAtomicCompareExchangeOp( 1662 llvm::Value *ExpectedVal, llvm::Value *DesiredVal, 1663 llvm::AtomicOrdering Success, llvm::AtomicOrdering Failure, bool IsWeak) { 1664 // Do the atomic store. 1665 Address Addr = getAtomicAddressAsAtomicIntPointer(); 1666 auto *Inst = CGF.Builder.CreateAtomicCmpXchg(Addr.getPointer(), 1667 ExpectedVal, DesiredVal, 1668 Success, Failure); 1669 // Other decoration. 1670 Inst->setVolatile(LVal.isVolatileQualified()); 1671 Inst->setWeak(IsWeak); 1672 1673 // Okay, turn that back into the original value type. 1674 auto *PreviousVal = CGF.Builder.CreateExtractValue(Inst, /*Idxs=*/0); 1675 auto *SuccessFailureVal = CGF.Builder.CreateExtractValue(Inst, /*Idxs=*/1); 1676 return std::make_pair(PreviousVal, SuccessFailureVal); 1677 } 1678 1679 llvm::Value * 1680 AtomicInfo::EmitAtomicCompareExchangeLibcall(llvm::Value *ExpectedAddr, 1681 llvm::Value *DesiredAddr, 1682 llvm::AtomicOrdering Success, 1683 llvm::AtomicOrdering Failure) { 1684 // bool __atomic_compare_exchange(size_t size, void *obj, void *expected, 1685 // void *desired, int success, int failure); 1686 CallArgList Args; 1687 Args.add(RValue::get(getAtomicSizeValue()), CGF.getContext().getSizeType()); 1688 Args.add(RValue::get(CGF.EmitCastToVoidPtr(getAtomicPointer())), 1689 CGF.getContext().VoidPtrTy); 1690 Args.add(RValue::get(CGF.EmitCastToVoidPtr(ExpectedAddr)), 1691 CGF.getContext().VoidPtrTy); 1692 Args.add(RValue::get(CGF.EmitCastToVoidPtr(DesiredAddr)), 1693 CGF.getContext().VoidPtrTy); 1694 Args.add(RValue::get( 1695 llvm::ConstantInt::get(CGF.IntTy, (int)llvm::toCABI(Success))), 1696 CGF.getContext().IntTy); 1697 Args.add(RValue::get( 1698 llvm::ConstantInt::get(CGF.IntTy, (int)llvm::toCABI(Failure))), 1699 CGF.getContext().IntTy); 1700 auto SuccessFailureRVal = emitAtomicLibcall(CGF, "__atomic_compare_exchange", 1701 CGF.getContext().BoolTy, Args); 1702 1703 return SuccessFailureRVal.getScalarVal(); 1704 } 1705 1706 std::pair<RValue, llvm::Value *> AtomicInfo::EmitAtomicCompareExchange( 1707 RValue Expected, RValue Desired, llvm::AtomicOrdering Success, 1708 llvm::AtomicOrdering Failure, bool IsWeak) { 1709 if (isStrongerThan(Failure, Success)) 1710 // Don't assert on undefined behavior "failure argument shall be no stronger 1711 // than the success argument". 1712 Failure = llvm::AtomicCmpXchgInst::getStrongestFailureOrdering(Success); 1713 1714 // Check whether we should use a library call. 1715 if (shouldUseLibcall()) { 1716 // Produce a source address. 1717 Address ExpectedAddr = materializeRValue(Expected); 1718 Address DesiredAddr = materializeRValue(Desired); 1719 auto *Res = EmitAtomicCompareExchangeLibcall(ExpectedAddr.getPointer(), 1720 DesiredAddr.getPointer(), 1721 Success, Failure); 1722 return std::make_pair( 1723 convertAtomicTempToRValue(ExpectedAddr, AggValueSlot::ignored(), 1724 SourceLocation(), /*AsValue=*/false), 1725 Res); 1726 } 1727 1728 // If we've got a scalar value of the right size, try to avoid going 1729 // through memory. 1730 auto *ExpectedVal = convertRValueToInt(Expected); 1731 auto *DesiredVal = convertRValueToInt(Desired); 1732 auto Res = EmitAtomicCompareExchangeOp(ExpectedVal, DesiredVal, Success, 1733 Failure, IsWeak); 1734 return std::make_pair( 1735 ConvertIntToValueOrAtomic(Res.first, AggValueSlot::ignored(), 1736 SourceLocation(), /*AsValue=*/false), 1737 Res.second); 1738 } 1739 1740 static void 1741 EmitAtomicUpdateValue(CodeGenFunction &CGF, AtomicInfo &Atomics, RValue OldRVal, 1742 const llvm::function_ref<RValue(RValue)> &UpdateOp, 1743 Address DesiredAddr) { 1744 RValue UpRVal; 1745 LValue AtomicLVal = Atomics.getAtomicLValue(); 1746 LValue DesiredLVal; 1747 if (AtomicLVal.isSimple()) { 1748 UpRVal = OldRVal; 1749 DesiredLVal = CGF.MakeAddrLValue(DesiredAddr, AtomicLVal.getType()); 1750 } else { 1751 // Build new lvalue for temp address. 1752 Address Ptr = Atomics.materializeRValue(OldRVal); 1753 LValue UpdateLVal; 1754 if (AtomicLVal.isBitField()) { 1755 UpdateLVal = 1756 LValue::MakeBitfield(Ptr, AtomicLVal.getBitFieldInfo(), 1757 AtomicLVal.getType(), 1758 AtomicLVal.getBaseInfo(), 1759 AtomicLVal.getTBAAInfo()); 1760 DesiredLVal = 1761 LValue::MakeBitfield(DesiredAddr, AtomicLVal.getBitFieldInfo(), 1762 AtomicLVal.getType(), AtomicLVal.getBaseInfo(), 1763 AtomicLVal.getTBAAInfo()); 1764 } else if (AtomicLVal.isVectorElt()) { 1765 UpdateLVal = LValue::MakeVectorElt(Ptr, AtomicLVal.getVectorIdx(), 1766 AtomicLVal.getType(), 1767 AtomicLVal.getBaseInfo(), 1768 AtomicLVal.getTBAAInfo()); 1769 DesiredLVal = LValue::MakeVectorElt( 1770 DesiredAddr, AtomicLVal.getVectorIdx(), AtomicLVal.getType(), 1771 AtomicLVal.getBaseInfo(), AtomicLVal.getTBAAInfo()); 1772 } else { 1773 assert(AtomicLVal.isExtVectorElt()); 1774 UpdateLVal = LValue::MakeExtVectorElt(Ptr, AtomicLVal.getExtVectorElts(), 1775 AtomicLVal.getType(), 1776 AtomicLVal.getBaseInfo(), 1777 AtomicLVal.getTBAAInfo()); 1778 DesiredLVal = LValue::MakeExtVectorElt( 1779 DesiredAddr, AtomicLVal.getExtVectorElts(), AtomicLVal.getType(), 1780 AtomicLVal.getBaseInfo(), AtomicLVal.getTBAAInfo()); 1781 } 1782 UpRVal = CGF.EmitLoadOfLValue(UpdateLVal, SourceLocation()); 1783 } 1784 // Store new value in the corresponding memory area. 1785 RValue NewRVal = UpdateOp(UpRVal); 1786 if (NewRVal.isScalar()) { 1787 CGF.EmitStoreThroughLValue(NewRVal, DesiredLVal); 1788 } else { 1789 assert(NewRVal.isComplex()); 1790 CGF.EmitStoreOfComplex(NewRVal.getComplexVal(), DesiredLVal, 1791 /*isInit=*/false); 1792 } 1793 } 1794 1795 void AtomicInfo::EmitAtomicUpdateLibcall( 1796 llvm::AtomicOrdering AO, const llvm::function_ref<RValue(RValue)> &UpdateOp, 1797 bool IsVolatile) { 1798 auto Failure = llvm::AtomicCmpXchgInst::getStrongestFailureOrdering(AO); 1799 1800 Address ExpectedAddr = CreateTempAlloca(); 1801 1802 EmitAtomicLoadLibcall(ExpectedAddr.getPointer(), AO, IsVolatile); 1803 auto *ContBB = CGF.createBasicBlock("atomic_cont"); 1804 auto *ExitBB = CGF.createBasicBlock("atomic_exit"); 1805 CGF.EmitBlock(ContBB); 1806 Address DesiredAddr = CreateTempAlloca(); 1807 if ((LVal.isBitField() && BFI.Size != ValueSizeInBits) || 1808 requiresMemSetZero(getAtomicAddress().getElementType())) { 1809 auto *OldVal = CGF.Builder.CreateLoad(ExpectedAddr); 1810 CGF.Builder.CreateStore(OldVal, DesiredAddr); 1811 } 1812 auto OldRVal = convertAtomicTempToRValue(ExpectedAddr, 1813 AggValueSlot::ignored(), 1814 SourceLocation(), /*AsValue=*/false); 1815 EmitAtomicUpdateValue(CGF, *this, OldRVal, UpdateOp, DesiredAddr); 1816 auto *Res = 1817 EmitAtomicCompareExchangeLibcall(ExpectedAddr.getPointer(), 1818 DesiredAddr.getPointer(), 1819 AO, Failure); 1820 CGF.Builder.CreateCondBr(Res, ExitBB, ContBB); 1821 CGF.EmitBlock(ExitBB, /*IsFinished=*/true); 1822 } 1823 1824 void AtomicInfo::EmitAtomicUpdateOp( 1825 llvm::AtomicOrdering AO, const llvm::function_ref<RValue(RValue)> &UpdateOp, 1826 bool IsVolatile) { 1827 auto Failure = llvm::AtomicCmpXchgInst::getStrongestFailureOrdering(AO); 1828 1829 // Do the atomic load. 1830 auto *OldVal = EmitAtomicLoadOp(Failure, IsVolatile); 1831 // For non-simple lvalues perform compare-and-swap procedure. 1832 auto *ContBB = CGF.createBasicBlock("atomic_cont"); 1833 auto *ExitBB = CGF.createBasicBlock("atomic_exit"); 1834 auto *CurBB = CGF.Builder.GetInsertBlock(); 1835 CGF.EmitBlock(ContBB); 1836 llvm::PHINode *PHI = CGF.Builder.CreatePHI(OldVal->getType(), 1837 /*NumReservedValues=*/2); 1838 PHI->addIncoming(OldVal, CurBB); 1839 Address NewAtomicAddr = CreateTempAlloca(); 1840 Address NewAtomicIntAddr = emitCastToAtomicIntPointer(NewAtomicAddr); 1841 if ((LVal.isBitField() && BFI.Size != ValueSizeInBits) || 1842 requiresMemSetZero(getAtomicAddress().getElementType())) { 1843 CGF.Builder.CreateStore(PHI, NewAtomicIntAddr); 1844 } 1845 auto OldRVal = ConvertIntToValueOrAtomic(PHI, AggValueSlot::ignored(), 1846 SourceLocation(), /*AsValue=*/false); 1847 EmitAtomicUpdateValue(CGF, *this, OldRVal, UpdateOp, NewAtomicAddr); 1848 auto *DesiredVal = CGF.Builder.CreateLoad(NewAtomicIntAddr); 1849 // Try to write new value using cmpxchg operation. 1850 auto Res = EmitAtomicCompareExchangeOp(PHI, DesiredVal, AO, Failure); 1851 PHI->addIncoming(Res.first, CGF.Builder.GetInsertBlock()); 1852 CGF.Builder.CreateCondBr(Res.second, ExitBB, ContBB); 1853 CGF.EmitBlock(ExitBB, /*IsFinished=*/true); 1854 } 1855 1856 static void EmitAtomicUpdateValue(CodeGenFunction &CGF, AtomicInfo &Atomics, 1857 RValue UpdateRVal, Address DesiredAddr) { 1858 LValue AtomicLVal = Atomics.getAtomicLValue(); 1859 LValue DesiredLVal; 1860 // Build new lvalue for temp address. 1861 if (AtomicLVal.isBitField()) { 1862 DesiredLVal = 1863 LValue::MakeBitfield(DesiredAddr, AtomicLVal.getBitFieldInfo(), 1864 AtomicLVal.getType(), AtomicLVal.getBaseInfo(), 1865 AtomicLVal.getTBAAInfo()); 1866 } else if (AtomicLVal.isVectorElt()) { 1867 DesiredLVal = 1868 LValue::MakeVectorElt(DesiredAddr, AtomicLVal.getVectorIdx(), 1869 AtomicLVal.getType(), AtomicLVal.getBaseInfo(), 1870 AtomicLVal.getTBAAInfo()); 1871 } else { 1872 assert(AtomicLVal.isExtVectorElt()); 1873 DesiredLVal = LValue::MakeExtVectorElt( 1874 DesiredAddr, AtomicLVal.getExtVectorElts(), AtomicLVal.getType(), 1875 AtomicLVal.getBaseInfo(), AtomicLVal.getTBAAInfo()); 1876 } 1877 // Store new value in the corresponding memory area. 1878 assert(UpdateRVal.isScalar()); 1879 CGF.EmitStoreThroughLValue(UpdateRVal, DesiredLVal); 1880 } 1881 1882 void AtomicInfo::EmitAtomicUpdateLibcall(llvm::AtomicOrdering AO, 1883 RValue UpdateRVal, bool IsVolatile) { 1884 auto Failure = llvm::AtomicCmpXchgInst::getStrongestFailureOrdering(AO); 1885 1886 Address ExpectedAddr = CreateTempAlloca(); 1887 1888 EmitAtomicLoadLibcall(ExpectedAddr.getPointer(), AO, IsVolatile); 1889 auto *ContBB = CGF.createBasicBlock("atomic_cont"); 1890 auto *ExitBB = CGF.createBasicBlock("atomic_exit"); 1891 CGF.EmitBlock(ContBB); 1892 Address DesiredAddr = CreateTempAlloca(); 1893 if ((LVal.isBitField() && BFI.Size != ValueSizeInBits) || 1894 requiresMemSetZero(getAtomicAddress().getElementType())) { 1895 auto *OldVal = CGF.Builder.CreateLoad(ExpectedAddr); 1896 CGF.Builder.CreateStore(OldVal, DesiredAddr); 1897 } 1898 EmitAtomicUpdateValue(CGF, *this, UpdateRVal, DesiredAddr); 1899 auto *Res = 1900 EmitAtomicCompareExchangeLibcall(ExpectedAddr.getPointer(), 1901 DesiredAddr.getPointer(), 1902 AO, Failure); 1903 CGF.Builder.CreateCondBr(Res, ExitBB, ContBB); 1904 CGF.EmitBlock(ExitBB, /*IsFinished=*/true); 1905 } 1906 1907 void AtomicInfo::EmitAtomicUpdateOp(llvm::AtomicOrdering AO, RValue UpdateRVal, 1908 bool IsVolatile) { 1909 auto Failure = llvm::AtomicCmpXchgInst::getStrongestFailureOrdering(AO); 1910 1911 // Do the atomic load. 1912 auto *OldVal = EmitAtomicLoadOp(Failure, IsVolatile); 1913 // For non-simple lvalues perform compare-and-swap procedure. 1914 auto *ContBB = CGF.createBasicBlock("atomic_cont"); 1915 auto *ExitBB = CGF.createBasicBlock("atomic_exit"); 1916 auto *CurBB = CGF.Builder.GetInsertBlock(); 1917 CGF.EmitBlock(ContBB); 1918 llvm::PHINode *PHI = CGF.Builder.CreatePHI(OldVal->getType(), 1919 /*NumReservedValues=*/2); 1920 PHI->addIncoming(OldVal, CurBB); 1921 Address NewAtomicAddr = CreateTempAlloca(); 1922 Address NewAtomicIntAddr = emitCastToAtomicIntPointer(NewAtomicAddr); 1923 if ((LVal.isBitField() && BFI.Size != ValueSizeInBits) || 1924 requiresMemSetZero(getAtomicAddress().getElementType())) { 1925 CGF.Builder.CreateStore(PHI, NewAtomicIntAddr); 1926 } 1927 EmitAtomicUpdateValue(CGF, *this, UpdateRVal, NewAtomicAddr); 1928 auto *DesiredVal = CGF.Builder.CreateLoad(NewAtomicIntAddr); 1929 // Try to write new value using cmpxchg operation. 1930 auto Res = EmitAtomicCompareExchangeOp(PHI, DesiredVal, AO, Failure); 1931 PHI->addIncoming(Res.first, CGF.Builder.GetInsertBlock()); 1932 CGF.Builder.CreateCondBr(Res.second, ExitBB, ContBB); 1933 CGF.EmitBlock(ExitBB, /*IsFinished=*/true); 1934 } 1935 1936 void AtomicInfo::EmitAtomicUpdate( 1937 llvm::AtomicOrdering AO, const llvm::function_ref<RValue(RValue)> &UpdateOp, 1938 bool IsVolatile) { 1939 if (shouldUseLibcall()) { 1940 EmitAtomicUpdateLibcall(AO, UpdateOp, IsVolatile); 1941 } else { 1942 EmitAtomicUpdateOp(AO, UpdateOp, IsVolatile); 1943 } 1944 } 1945 1946 void AtomicInfo::EmitAtomicUpdate(llvm::AtomicOrdering AO, RValue UpdateRVal, 1947 bool IsVolatile) { 1948 if (shouldUseLibcall()) { 1949 EmitAtomicUpdateLibcall(AO, UpdateRVal, IsVolatile); 1950 } else { 1951 EmitAtomicUpdateOp(AO, UpdateRVal, IsVolatile); 1952 } 1953 } 1954 1955 void CodeGenFunction::EmitAtomicStore(RValue rvalue, LValue lvalue, 1956 bool isInit) { 1957 bool IsVolatile = lvalue.isVolatileQualified(); 1958 llvm::AtomicOrdering AO; 1959 if (lvalue.getType()->isAtomicType()) { 1960 AO = llvm::AtomicOrdering::SequentiallyConsistent; 1961 } else { 1962 AO = llvm::AtomicOrdering::Release; 1963 IsVolatile = true; 1964 } 1965 return EmitAtomicStore(rvalue, lvalue, AO, IsVolatile, isInit); 1966 } 1967 1968 /// Emit a store to an l-value of atomic type. 1969 /// 1970 /// Note that the r-value is expected to be an r-value *of the atomic 1971 /// type*; this means that for aggregate r-values, it should include 1972 /// storage for any padding that was necessary. 1973 void CodeGenFunction::EmitAtomicStore(RValue rvalue, LValue dest, 1974 llvm::AtomicOrdering AO, bool IsVolatile, 1975 bool isInit) { 1976 // If this is an aggregate r-value, it should agree in type except 1977 // maybe for address-space qualification. 1978 assert(!rvalue.isAggregate() || 1979 rvalue.getAggregateAddress().getElementType() == 1980 dest.getAddress(*this).getElementType()); 1981 1982 AtomicInfo atomics(*this, dest); 1983 LValue LVal = atomics.getAtomicLValue(); 1984 1985 // If this is an initialization, just put the value there normally. 1986 if (LVal.isSimple()) { 1987 if (isInit) { 1988 atomics.emitCopyIntoMemory(rvalue); 1989 return; 1990 } 1991 1992 // Check whether we should use a library call. 1993 if (atomics.shouldUseLibcall()) { 1994 // Produce a source address. 1995 Address srcAddr = atomics.materializeRValue(rvalue); 1996 1997 // void __atomic_store(size_t size, void *mem, void *val, int order) 1998 CallArgList args; 1999 args.add(RValue::get(atomics.getAtomicSizeValue()), 2000 getContext().getSizeType()); 2001 args.add(RValue::get(EmitCastToVoidPtr(atomics.getAtomicPointer())), 2002 getContext().VoidPtrTy); 2003 args.add(RValue::get(EmitCastToVoidPtr(srcAddr.getPointer())), 2004 getContext().VoidPtrTy); 2005 args.add( 2006 RValue::get(llvm::ConstantInt::get(IntTy, (int)llvm::toCABI(AO))), 2007 getContext().IntTy); 2008 emitAtomicLibcall(*this, "__atomic_store", getContext().VoidTy, args); 2009 return; 2010 } 2011 2012 // Okay, we're doing this natively. 2013 llvm::Value *intValue = atomics.convertRValueToInt(rvalue); 2014 2015 // Do the atomic store. 2016 Address addr = 2017 atomics.emitCastToAtomicIntPointer(atomics.getAtomicAddress()); 2018 intValue = Builder.CreateIntCast( 2019 intValue, addr.getElementType(), /*isSigned=*/false); 2020 llvm::StoreInst *store = Builder.CreateStore(intValue, addr); 2021 2022 if (AO == llvm::AtomicOrdering::Acquire) 2023 AO = llvm::AtomicOrdering::Monotonic; 2024 else if (AO == llvm::AtomicOrdering::AcquireRelease) 2025 AO = llvm::AtomicOrdering::Release; 2026 // Initializations don't need to be atomic. 2027 if (!isInit) 2028 store->setAtomic(AO); 2029 2030 // Other decoration. 2031 if (IsVolatile) 2032 store->setVolatile(true); 2033 CGM.DecorateInstructionWithTBAA(store, dest.getTBAAInfo()); 2034 return; 2035 } 2036 2037 // Emit simple atomic update operation. 2038 atomics.EmitAtomicUpdate(AO, rvalue, IsVolatile); 2039 } 2040 2041 /// Emit a compare-and-exchange op for atomic type. 2042 /// 2043 std::pair<RValue, llvm::Value *> CodeGenFunction::EmitAtomicCompareExchange( 2044 LValue Obj, RValue Expected, RValue Desired, SourceLocation Loc, 2045 llvm::AtomicOrdering Success, llvm::AtomicOrdering Failure, bool IsWeak, 2046 AggValueSlot Slot) { 2047 // If this is an aggregate r-value, it should agree in type except 2048 // maybe for address-space qualification. 2049 assert(!Expected.isAggregate() || 2050 Expected.getAggregateAddress().getElementType() == 2051 Obj.getAddress(*this).getElementType()); 2052 assert(!Desired.isAggregate() || 2053 Desired.getAggregateAddress().getElementType() == 2054 Obj.getAddress(*this).getElementType()); 2055 AtomicInfo Atomics(*this, Obj); 2056 2057 return Atomics.EmitAtomicCompareExchange(Expected, Desired, Success, Failure, 2058 IsWeak); 2059 } 2060 2061 void CodeGenFunction::EmitAtomicUpdate( 2062 LValue LVal, llvm::AtomicOrdering AO, 2063 const llvm::function_ref<RValue(RValue)> &UpdateOp, bool IsVolatile) { 2064 AtomicInfo Atomics(*this, LVal); 2065 Atomics.EmitAtomicUpdate(AO, UpdateOp, IsVolatile); 2066 } 2067 2068 void CodeGenFunction::EmitAtomicInit(Expr *init, LValue dest) { 2069 AtomicInfo atomics(*this, dest); 2070 2071 switch (atomics.getEvaluationKind()) { 2072 case TEK_Scalar: { 2073 llvm::Value *value = EmitScalarExpr(init); 2074 atomics.emitCopyIntoMemory(RValue::get(value)); 2075 return; 2076 } 2077 2078 case TEK_Complex: { 2079 ComplexPairTy value = EmitComplexExpr(init); 2080 atomics.emitCopyIntoMemory(RValue::getComplex(value)); 2081 return; 2082 } 2083 2084 case TEK_Aggregate: { 2085 // Fix up the destination if the initializer isn't an expression 2086 // of atomic type. 2087 bool Zeroed = false; 2088 if (!init->getType()->isAtomicType()) { 2089 Zeroed = atomics.emitMemSetZeroIfNecessary(); 2090 dest = atomics.projectValue(); 2091 } 2092 2093 // Evaluate the expression directly into the destination. 2094 AggValueSlot slot = AggValueSlot::forLValue( 2095 dest, *this, AggValueSlot::IsNotDestructed, 2096 AggValueSlot::DoesNotNeedGCBarriers, AggValueSlot::IsNotAliased, 2097 AggValueSlot::DoesNotOverlap, 2098 Zeroed ? AggValueSlot::IsZeroed : AggValueSlot::IsNotZeroed); 2099 2100 EmitAggExpr(init, slot); 2101 return; 2102 } 2103 } 2104 llvm_unreachable("bad evaluation kind"); 2105 } 2106