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::FixedVectorType>( 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::AttrBuilder fnAttrB; 311 fnAttrB.addAttribute(llvm::Attribute::NoUnwind); 312 fnAttrB.addAttribute(llvm::Attribute::WillReturn); 313 llvm::AttributeList fnAttrs = llvm::AttributeList::get( 314 CGF.getLLVMContext(), llvm::AttributeList::FunctionIndex, fnAttrB); 315 316 llvm::FunctionCallee fn = 317 CGF.CGM.CreateRuntimeFunction(fnTy, fnName, fnAttrs); 318 auto callee = CGCallee::forDirect(fn); 319 return CGF.EmitCall(fnInfo, callee, ReturnValueSlot(), args); 320 } 321 322 /// Does a store of the given IR type modify the full expected width? 323 static bool isFullSizeType(CodeGenModule &CGM, llvm::Type *type, 324 uint64_t expectedSize) { 325 return (CGM.getDataLayout().getTypeStoreSize(type) * 8 == expectedSize); 326 } 327 328 /// Does the atomic type require memsetting to zero before initialization? 329 /// 330 /// The IR type is provided as a way of making certain queries faster. 331 bool AtomicInfo::requiresMemSetZero(llvm::Type *type) const { 332 // If the atomic type has size padding, we definitely need a memset. 333 if (hasPadding()) return true; 334 335 // Otherwise, do some simple heuristics to try to avoid it: 336 switch (getEvaluationKind()) { 337 // For scalars and complexes, check whether the store size of the 338 // type uses the full size. 339 case TEK_Scalar: 340 return !isFullSizeType(CGF.CGM, type, AtomicSizeInBits); 341 case TEK_Complex: 342 return !isFullSizeType(CGF.CGM, type->getStructElementType(0), 343 AtomicSizeInBits / 2); 344 345 // Padding in structs has an undefined bit pattern. User beware. 346 case TEK_Aggregate: 347 return false; 348 } 349 llvm_unreachable("bad evaluation kind"); 350 } 351 352 bool AtomicInfo::emitMemSetZeroIfNecessary() const { 353 assert(LVal.isSimple()); 354 llvm::Value *addr = LVal.getPointer(CGF); 355 if (!requiresMemSetZero(addr->getType()->getPointerElementType())) 356 return false; 357 358 CGF.Builder.CreateMemSet( 359 addr, llvm::ConstantInt::get(CGF.Int8Ty, 0), 360 CGF.getContext().toCharUnitsFromBits(AtomicSizeInBits).getQuantity(), 361 LVal.getAlignment().getAsAlign()); 362 return true; 363 } 364 365 static void emitAtomicCmpXchg(CodeGenFunction &CGF, AtomicExpr *E, bool IsWeak, 366 Address Dest, Address Ptr, 367 Address Val1, Address Val2, 368 uint64_t Size, 369 llvm::AtomicOrdering SuccessOrder, 370 llvm::AtomicOrdering FailureOrder, 371 llvm::SyncScope::ID Scope) { 372 // Note that cmpxchg doesn't support weak cmpxchg, at least at the moment. 373 llvm::Value *Expected = CGF.Builder.CreateLoad(Val1); 374 llvm::Value *Desired = CGF.Builder.CreateLoad(Val2); 375 376 llvm::AtomicCmpXchgInst *Pair = CGF.Builder.CreateAtomicCmpXchg( 377 Ptr.getPointer(), Expected, Desired, SuccessOrder, FailureOrder, 378 Scope); 379 Pair->setVolatile(E->isVolatile()); 380 Pair->setWeak(IsWeak); 381 382 // Cmp holds the result of the compare-exchange operation: true on success, 383 // false on failure. 384 llvm::Value *Old = CGF.Builder.CreateExtractValue(Pair, 0); 385 llvm::Value *Cmp = CGF.Builder.CreateExtractValue(Pair, 1); 386 387 // This basic block is used to hold the store instruction if the operation 388 // failed. 389 llvm::BasicBlock *StoreExpectedBB = 390 CGF.createBasicBlock("cmpxchg.store_expected", CGF.CurFn); 391 392 // This basic block is the exit point of the operation, we should end up 393 // here regardless of whether or not the operation succeeded. 394 llvm::BasicBlock *ContinueBB = 395 CGF.createBasicBlock("cmpxchg.continue", CGF.CurFn); 396 397 // Update Expected if Expected isn't equal to Old, otherwise branch to the 398 // exit point. 399 CGF.Builder.CreateCondBr(Cmp, ContinueBB, StoreExpectedBB); 400 401 CGF.Builder.SetInsertPoint(StoreExpectedBB); 402 // Update the memory at Expected with Old's value. 403 CGF.Builder.CreateStore(Old, Val1); 404 // Finally, branch to the exit point. 405 CGF.Builder.CreateBr(ContinueBB); 406 407 CGF.Builder.SetInsertPoint(ContinueBB); 408 // Update the memory at Dest with Cmp's value. 409 CGF.EmitStoreOfScalar(Cmp, CGF.MakeAddrLValue(Dest, E->getType())); 410 } 411 412 /// Given an ordering required on success, emit all possible cmpxchg 413 /// instructions to cope with the provided (but possibly only dynamically known) 414 /// FailureOrder. 415 static void emitAtomicCmpXchgFailureSet(CodeGenFunction &CGF, AtomicExpr *E, 416 bool IsWeak, Address Dest, Address Ptr, 417 Address Val1, Address Val2, 418 llvm::Value *FailureOrderVal, 419 uint64_t Size, 420 llvm::AtomicOrdering SuccessOrder, 421 llvm::SyncScope::ID Scope) { 422 llvm::AtomicOrdering FailureOrder; 423 if (llvm::ConstantInt *FO = dyn_cast<llvm::ConstantInt>(FailureOrderVal)) { 424 auto FOS = FO->getSExtValue(); 425 if (!llvm::isValidAtomicOrderingCABI(FOS)) 426 FailureOrder = llvm::AtomicOrdering::Monotonic; 427 else 428 switch ((llvm::AtomicOrderingCABI)FOS) { 429 case llvm::AtomicOrderingCABI::relaxed: 430 case llvm::AtomicOrderingCABI::release: 431 case llvm::AtomicOrderingCABI::acq_rel: 432 FailureOrder = llvm::AtomicOrdering::Monotonic; 433 break; 434 case llvm::AtomicOrderingCABI::consume: 435 case llvm::AtomicOrderingCABI::acquire: 436 FailureOrder = llvm::AtomicOrdering::Acquire; 437 break; 438 case llvm::AtomicOrderingCABI::seq_cst: 439 FailureOrder = llvm::AtomicOrdering::SequentiallyConsistent; 440 break; 441 } 442 if (isStrongerThan(FailureOrder, SuccessOrder)) { 443 // Don't assert on undefined behavior "failure argument shall be no 444 // stronger than the success argument". 445 FailureOrder = 446 llvm::AtomicCmpXchgInst::getStrongestFailureOrdering(SuccessOrder); 447 } 448 emitAtomicCmpXchg(CGF, E, IsWeak, Dest, Ptr, Val1, Val2, Size, SuccessOrder, 449 FailureOrder, Scope); 450 return; 451 } 452 453 // Create all the relevant BB's 454 llvm::BasicBlock *MonotonicBB = nullptr, *AcquireBB = nullptr, 455 *SeqCstBB = nullptr; 456 MonotonicBB = CGF.createBasicBlock("monotonic_fail", CGF.CurFn); 457 if (SuccessOrder != llvm::AtomicOrdering::Monotonic && 458 SuccessOrder != llvm::AtomicOrdering::Release) 459 AcquireBB = CGF.createBasicBlock("acquire_fail", CGF.CurFn); 460 if (SuccessOrder == llvm::AtomicOrdering::SequentiallyConsistent) 461 SeqCstBB = CGF.createBasicBlock("seqcst_fail", CGF.CurFn); 462 463 llvm::BasicBlock *ContBB = CGF.createBasicBlock("atomic.continue", CGF.CurFn); 464 465 llvm::SwitchInst *SI = CGF.Builder.CreateSwitch(FailureOrderVal, MonotonicBB); 466 467 // Emit all the different atomics 468 469 // MonotonicBB is arbitrarily chosen as the default case; in practice, this 470 // doesn't matter unless someone is crazy enough to use something that 471 // doesn't fold to a constant for the ordering. 472 CGF.Builder.SetInsertPoint(MonotonicBB); 473 emitAtomicCmpXchg(CGF, E, IsWeak, Dest, Ptr, Val1, Val2, 474 Size, SuccessOrder, llvm::AtomicOrdering::Monotonic, Scope); 475 CGF.Builder.CreateBr(ContBB); 476 477 if (AcquireBB) { 478 CGF.Builder.SetInsertPoint(AcquireBB); 479 emitAtomicCmpXchg(CGF, E, IsWeak, Dest, Ptr, Val1, Val2, 480 Size, SuccessOrder, llvm::AtomicOrdering::Acquire, Scope); 481 CGF.Builder.CreateBr(ContBB); 482 SI->addCase(CGF.Builder.getInt32((int)llvm::AtomicOrderingCABI::consume), 483 AcquireBB); 484 SI->addCase(CGF.Builder.getInt32((int)llvm::AtomicOrderingCABI::acquire), 485 AcquireBB); 486 } 487 if (SeqCstBB) { 488 CGF.Builder.SetInsertPoint(SeqCstBB); 489 emitAtomicCmpXchg(CGF, E, IsWeak, Dest, Ptr, Val1, Val2, Size, SuccessOrder, 490 llvm::AtomicOrdering::SequentiallyConsistent, Scope); 491 CGF.Builder.CreateBr(ContBB); 492 SI->addCase(CGF.Builder.getInt32((int)llvm::AtomicOrderingCABI::seq_cst), 493 SeqCstBB); 494 } 495 496 CGF.Builder.SetInsertPoint(ContBB); 497 } 498 499 /// Duplicate the atomic min/max operation in conventional IR for the builtin 500 /// variants that return the new rather than the original value. 501 static llvm::Value *EmitPostAtomicMinMax(CGBuilderTy &Builder, 502 AtomicExpr::AtomicOp Op, 503 bool IsSigned, 504 llvm::Value *OldVal, 505 llvm::Value *RHS) { 506 llvm::CmpInst::Predicate Pred; 507 switch (Op) { 508 default: 509 llvm_unreachable("Unexpected min/max operation"); 510 case AtomicExpr::AO__atomic_max_fetch: 511 Pred = IsSigned ? llvm::CmpInst::ICMP_SGT : llvm::CmpInst::ICMP_UGT; 512 break; 513 case AtomicExpr::AO__atomic_min_fetch: 514 Pred = IsSigned ? llvm::CmpInst::ICMP_SLT : llvm::CmpInst::ICMP_ULT; 515 break; 516 } 517 llvm::Value *Cmp = Builder.CreateICmp(Pred, OldVal, RHS, "tst"); 518 return Builder.CreateSelect(Cmp, OldVal, RHS, "newval"); 519 } 520 521 static void EmitAtomicOp(CodeGenFunction &CGF, AtomicExpr *E, Address Dest, 522 Address Ptr, Address Val1, Address Val2, 523 llvm::Value *IsWeak, llvm::Value *FailureOrder, 524 uint64_t Size, llvm::AtomicOrdering Order, 525 llvm::SyncScope::ID Scope) { 526 llvm::AtomicRMWInst::BinOp Op = llvm::AtomicRMWInst::Add; 527 bool PostOpMinMax = false; 528 unsigned PostOp = 0; 529 530 switch (E->getOp()) { 531 case AtomicExpr::AO__c11_atomic_init: 532 case AtomicExpr::AO__opencl_atomic_init: 533 llvm_unreachable("Already handled!"); 534 535 case AtomicExpr::AO__c11_atomic_compare_exchange_strong: 536 case AtomicExpr::AO__opencl_atomic_compare_exchange_strong: 537 emitAtomicCmpXchgFailureSet(CGF, E, false, Dest, Ptr, Val1, Val2, 538 FailureOrder, Size, Order, Scope); 539 return; 540 case AtomicExpr::AO__c11_atomic_compare_exchange_weak: 541 case AtomicExpr::AO__opencl_atomic_compare_exchange_weak: 542 emitAtomicCmpXchgFailureSet(CGF, E, true, Dest, Ptr, Val1, Val2, 543 FailureOrder, Size, Order, Scope); 544 return; 545 case AtomicExpr::AO__atomic_compare_exchange: 546 case AtomicExpr::AO__atomic_compare_exchange_n: { 547 if (llvm::ConstantInt *IsWeakC = dyn_cast<llvm::ConstantInt>(IsWeak)) { 548 emitAtomicCmpXchgFailureSet(CGF, E, IsWeakC->getZExtValue(), Dest, Ptr, 549 Val1, Val2, FailureOrder, Size, Order, Scope); 550 } else { 551 // Create all the relevant BB's 552 llvm::BasicBlock *StrongBB = 553 CGF.createBasicBlock("cmpxchg.strong", CGF.CurFn); 554 llvm::BasicBlock *WeakBB = CGF.createBasicBlock("cmxchg.weak", CGF.CurFn); 555 llvm::BasicBlock *ContBB = 556 CGF.createBasicBlock("cmpxchg.continue", CGF.CurFn); 557 558 llvm::SwitchInst *SI = CGF.Builder.CreateSwitch(IsWeak, WeakBB); 559 SI->addCase(CGF.Builder.getInt1(false), StrongBB); 560 561 CGF.Builder.SetInsertPoint(StrongBB); 562 emitAtomicCmpXchgFailureSet(CGF, E, false, Dest, Ptr, Val1, Val2, 563 FailureOrder, Size, Order, Scope); 564 CGF.Builder.CreateBr(ContBB); 565 566 CGF.Builder.SetInsertPoint(WeakBB); 567 emitAtomicCmpXchgFailureSet(CGF, E, true, Dest, Ptr, Val1, Val2, 568 FailureOrder, Size, Order, Scope); 569 CGF.Builder.CreateBr(ContBB); 570 571 CGF.Builder.SetInsertPoint(ContBB); 572 } 573 return; 574 } 575 case AtomicExpr::AO__c11_atomic_load: 576 case AtomicExpr::AO__opencl_atomic_load: 577 case AtomicExpr::AO__atomic_load_n: 578 case AtomicExpr::AO__atomic_load: { 579 llvm::LoadInst *Load = CGF.Builder.CreateLoad(Ptr); 580 Load->setAtomic(Order, Scope); 581 Load->setVolatile(E->isVolatile()); 582 CGF.Builder.CreateStore(Load, Dest); 583 return; 584 } 585 586 case AtomicExpr::AO__c11_atomic_store: 587 case AtomicExpr::AO__opencl_atomic_store: 588 case AtomicExpr::AO__atomic_store: 589 case AtomicExpr::AO__atomic_store_n: { 590 llvm::Value *LoadVal1 = CGF.Builder.CreateLoad(Val1); 591 llvm::StoreInst *Store = CGF.Builder.CreateStore(LoadVal1, Ptr); 592 Store->setAtomic(Order, Scope); 593 Store->setVolatile(E->isVolatile()); 594 return; 595 } 596 597 case AtomicExpr::AO__c11_atomic_exchange: 598 case AtomicExpr::AO__opencl_atomic_exchange: 599 case AtomicExpr::AO__atomic_exchange_n: 600 case AtomicExpr::AO__atomic_exchange: 601 Op = llvm::AtomicRMWInst::Xchg; 602 break; 603 604 case AtomicExpr::AO__atomic_add_fetch: 605 PostOp = llvm::Instruction::Add; 606 LLVM_FALLTHROUGH; 607 case AtomicExpr::AO__c11_atomic_fetch_add: 608 case AtomicExpr::AO__opencl_atomic_fetch_add: 609 case AtomicExpr::AO__atomic_fetch_add: 610 Op = llvm::AtomicRMWInst::Add; 611 break; 612 613 case AtomicExpr::AO__atomic_sub_fetch: 614 PostOp = llvm::Instruction::Sub; 615 LLVM_FALLTHROUGH; 616 case AtomicExpr::AO__c11_atomic_fetch_sub: 617 case AtomicExpr::AO__opencl_atomic_fetch_sub: 618 case AtomicExpr::AO__atomic_fetch_sub: 619 Op = llvm::AtomicRMWInst::Sub; 620 break; 621 622 case AtomicExpr::AO__atomic_min_fetch: 623 PostOpMinMax = true; 624 LLVM_FALLTHROUGH; 625 case AtomicExpr::AO__c11_atomic_fetch_min: 626 case AtomicExpr::AO__opencl_atomic_fetch_min: 627 case AtomicExpr::AO__atomic_fetch_min: 628 Op = E->getValueType()->isSignedIntegerType() ? llvm::AtomicRMWInst::Min 629 : llvm::AtomicRMWInst::UMin; 630 break; 631 632 case AtomicExpr::AO__atomic_max_fetch: 633 PostOpMinMax = true; 634 LLVM_FALLTHROUGH; 635 case AtomicExpr::AO__c11_atomic_fetch_max: 636 case AtomicExpr::AO__opencl_atomic_fetch_max: 637 case AtomicExpr::AO__atomic_fetch_max: 638 Op = E->getValueType()->isSignedIntegerType() ? llvm::AtomicRMWInst::Max 639 : llvm::AtomicRMWInst::UMax; 640 break; 641 642 case AtomicExpr::AO__atomic_and_fetch: 643 PostOp = llvm::Instruction::And; 644 LLVM_FALLTHROUGH; 645 case AtomicExpr::AO__c11_atomic_fetch_and: 646 case AtomicExpr::AO__opencl_atomic_fetch_and: 647 case AtomicExpr::AO__atomic_fetch_and: 648 Op = llvm::AtomicRMWInst::And; 649 break; 650 651 case AtomicExpr::AO__atomic_or_fetch: 652 PostOp = llvm::Instruction::Or; 653 LLVM_FALLTHROUGH; 654 case AtomicExpr::AO__c11_atomic_fetch_or: 655 case AtomicExpr::AO__opencl_atomic_fetch_or: 656 case AtomicExpr::AO__atomic_fetch_or: 657 Op = llvm::AtomicRMWInst::Or; 658 break; 659 660 case AtomicExpr::AO__atomic_xor_fetch: 661 PostOp = llvm::Instruction::Xor; 662 LLVM_FALLTHROUGH; 663 case AtomicExpr::AO__c11_atomic_fetch_xor: 664 case AtomicExpr::AO__opencl_atomic_fetch_xor: 665 case AtomicExpr::AO__atomic_fetch_xor: 666 Op = llvm::AtomicRMWInst::Xor; 667 break; 668 669 case AtomicExpr::AO__atomic_nand_fetch: 670 PostOp = llvm::Instruction::And; // the NOT is special cased below 671 LLVM_FALLTHROUGH; 672 case AtomicExpr::AO__atomic_fetch_nand: 673 Op = llvm::AtomicRMWInst::Nand; 674 break; 675 } 676 677 llvm::Value *LoadVal1 = CGF.Builder.CreateLoad(Val1); 678 llvm::AtomicRMWInst *RMWI = 679 CGF.Builder.CreateAtomicRMW(Op, Ptr.getPointer(), LoadVal1, Order, Scope); 680 RMWI->setVolatile(E->isVolatile()); 681 682 // For __atomic_*_fetch operations, perform the operation again to 683 // determine the value which was written. 684 llvm::Value *Result = RMWI; 685 if (PostOpMinMax) 686 Result = EmitPostAtomicMinMax(CGF.Builder, E->getOp(), 687 E->getValueType()->isSignedIntegerType(), 688 RMWI, LoadVal1); 689 else if (PostOp) 690 Result = CGF.Builder.CreateBinOp((llvm::Instruction::BinaryOps)PostOp, RMWI, 691 LoadVal1); 692 if (E->getOp() == AtomicExpr::AO__atomic_nand_fetch) 693 Result = CGF.Builder.CreateNot(Result); 694 CGF.Builder.CreateStore(Result, Dest); 695 } 696 697 // This function emits any expression (scalar, complex, or aggregate) 698 // into a temporary alloca. 699 static Address 700 EmitValToTemp(CodeGenFunction &CGF, Expr *E) { 701 Address DeclPtr = CGF.CreateMemTemp(E->getType(), ".atomictmp"); 702 CGF.EmitAnyExprToMem(E, DeclPtr, E->getType().getQualifiers(), 703 /*Init*/ true); 704 return DeclPtr; 705 } 706 707 static void EmitAtomicOp(CodeGenFunction &CGF, AtomicExpr *Expr, Address Dest, 708 Address Ptr, Address Val1, Address Val2, 709 llvm::Value *IsWeak, llvm::Value *FailureOrder, 710 uint64_t Size, llvm::AtomicOrdering Order, 711 llvm::Value *Scope) { 712 auto ScopeModel = Expr->getScopeModel(); 713 714 // LLVM atomic instructions always have synch scope. If clang atomic 715 // expression has no scope operand, use default LLVM synch scope. 716 if (!ScopeModel) { 717 EmitAtomicOp(CGF, Expr, Dest, Ptr, Val1, Val2, IsWeak, FailureOrder, Size, 718 Order, CGF.CGM.getLLVMContext().getOrInsertSyncScopeID("")); 719 return; 720 } 721 722 // Handle constant scope. 723 if (auto SC = dyn_cast<llvm::ConstantInt>(Scope)) { 724 auto SCID = CGF.getTargetHooks().getLLVMSyncScopeID( 725 CGF.CGM.getLangOpts(), ScopeModel->map(SC->getZExtValue()), 726 Order, CGF.CGM.getLLVMContext()); 727 EmitAtomicOp(CGF, Expr, Dest, Ptr, Val1, Val2, IsWeak, FailureOrder, Size, 728 Order, SCID); 729 return; 730 } 731 732 // Handle non-constant scope. 733 auto &Builder = CGF.Builder; 734 auto Scopes = ScopeModel->getRuntimeValues(); 735 llvm::DenseMap<unsigned, llvm::BasicBlock *> BB; 736 for (auto S : Scopes) 737 BB[S] = CGF.createBasicBlock(getAsString(ScopeModel->map(S)), CGF.CurFn); 738 739 llvm::BasicBlock *ContBB = 740 CGF.createBasicBlock("atomic.scope.continue", CGF.CurFn); 741 742 auto *SC = Builder.CreateIntCast(Scope, Builder.getInt32Ty(), false); 743 // If unsupported synch scope is encountered at run time, assume a fallback 744 // synch scope value. 745 auto FallBack = ScopeModel->getFallBackValue(); 746 llvm::SwitchInst *SI = Builder.CreateSwitch(SC, BB[FallBack]); 747 for (auto S : Scopes) { 748 auto *B = BB[S]; 749 if (S != FallBack) 750 SI->addCase(Builder.getInt32(S), B); 751 752 Builder.SetInsertPoint(B); 753 EmitAtomicOp(CGF, Expr, Dest, Ptr, Val1, Val2, IsWeak, FailureOrder, Size, 754 Order, 755 CGF.getTargetHooks().getLLVMSyncScopeID(CGF.CGM.getLangOpts(), 756 ScopeModel->map(S), 757 Order, 758 CGF.getLLVMContext())); 759 Builder.CreateBr(ContBB); 760 } 761 762 Builder.SetInsertPoint(ContBB); 763 } 764 765 static void 766 AddDirectArgument(CodeGenFunction &CGF, CallArgList &Args, 767 bool UseOptimizedLibcall, llvm::Value *Val, QualType ValTy, 768 SourceLocation Loc, CharUnits SizeInChars) { 769 if (UseOptimizedLibcall) { 770 // Load value and pass it to the function directly. 771 CharUnits Align = CGF.getContext().getTypeAlignInChars(ValTy); 772 int64_t SizeInBits = CGF.getContext().toBits(SizeInChars); 773 ValTy = 774 CGF.getContext().getIntTypeForBitwidth(SizeInBits, /*Signed=*/false); 775 llvm::Type *IPtrTy = llvm::IntegerType::get(CGF.getLLVMContext(), 776 SizeInBits)->getPointerTo(); 777 Address Ptr = Address(CGF.Builder.CreateBitCast(Val, IPtrTy), Align); 778 Val = CGF.EmitLoadOfScalar(Ptr, false, 779 CGF.getContext().getPointerType(ValTy), 780 Loc); 781 // Coerce the value into an appropriately sized integer type. 782 Args.add(RValue::get(Val), ValTy); 783 } else { 784 // Non-optimized functions always take a reference. 785 Args.add(RValue::get(CGF.EmitCastToVoidPtr(Val)), 786 CGF.getContext().VoidPtrTy); 787 } 788 } 789 790 RValue CodeGenFunction::EmitAtomicExpr(AtomicExpr *E) { 791 QualType AtomicTy = E->getPtr()->getType()->getPointeeType(); 792 QualType MemTy = AtomicTy; 793 if (const AtomicType *AT = AtomicTy->getAs<AtomicType>()) 794 MemTy = AT->getValueType(); 795 llvm::Value *IsWeak = nullptr, *OrderFail = nullptr; 796 797 Address Val1 = Address::invalid(); 798 Address Val2 = Address::invalid(); 799 Address Dest = Address::invalid(); 800 Address Ptr = EmitPointerWithAlignment(E->getPtr()); 801 802 if (E->getOp() == AtomicExpr::AO__c11_atomic_init || 803 E->getOp() == AtomicExpr::AO__opencl_atomic_init) { 804 LValue lvalue = MakeAddrLValue(Ptr, AtomicTy); 805 EmitAtomicInit(E->getVal1(), lvalue); 806 return RValue::get(nullptr); 807 } 808 809 auto TInfo = getContext().getTypeInfoInChars(AtomicTy); 810 uint64_t Size = TInfo.Width.getQuantity(); 811 unsigned MaxInlineWidthInBits = getTarget().getMaxAtomicInlineWidth(); 812 813 bool Oversized = getContext().toBits(TInfo.Width) > MaxInlineWidthInBits; 814 bool Misaligned = (Ptr.getAlignment() % TInfo.Width) != 0; 815 bool UseLibcall = Misaligned | Oversized; 816 CharUnits MaxInlineWidth = 817 getContext().toCharUnitsFromBits(MaxInlineWidthInBits); 818 819 DiagnosticsEngine &Diags = CGM.getDiags(); 820 821 if (Misaligned) { 822 Diags.Report(E->getBeginLoc(), diag::warn_atomic_op_misaligned) 823 << (int)TInfo.Width.getQuantity() 824 << (int)Ptr.getAlignment().getQuantity(); 825 } 826 827 if (Oversized) { 828 Diags.Report(E->getBeginLoc(), diag::warn_atomic_op_oversized) 829 << (int)TInfo.Width.getQuantity() << (int)MaxInlineWidth.getQuantity(); 830 } 831 832 llvm::Value *Order = EmitScalarExpr(E->getOrder()); 833 llvm::Value *Scope = 834 E->getScopeModel() ? EmitScalarExpr(E->getScope()) : nullptr; 835 836 switch (E->getOp()) { 837 case AtomicExpr::AO__c11_atomic_init: 838 case AtomicExpr::AO__opencl_atomic_init: 839 llvm_unreachable("Already handled above with EmitAtomicInit!"); 840 841 case AtomicExpr::AO__c11_atomic_load: 842 case AtomicExpr::AO__opencl_atomic_load: 843 case AtomicExpr::AO__atomic_load_n: 844 break; 845 846 case AtomicExpr::AO__atomic_load: 847 Dest = EmitPointerWithAlignment(E->getVal1()); 848 break; 849 850 case AtomicExpr::AO__atomic_store: 851 Val1 = EmitPointerWithAlignment(E->getVal1()); 852 break; 853 854 case AtomicExpr::AO__atomic_exchange: 855 Val1 = EmitPointerWithAlignment(E->getVal1()); 856 Dest = EmitPointerWithAlignment(E->getVal2()); 857 break; 858 859 case AtomicExpr::AO__c11_atomic_compare_exchange_strong: 860 case AtomicExpr::AO__c11_atomic_compare_exchange_weak: 861 case AtomicExpr::AO__opencl_atomic_compare_exchange_strong: 862 case AtomicExpr::AO__opencl_atomic_compare_exchange_weak: 863 case AtomicExpr::AO__atomic_compare_exchange_n: 864 case AtomicExpr::AO__atomic_compare_exchange: 865 Val1 = EmitPointerWithAlignment(E->getVal1()); 866 if (E->getOp() == AtomicExpr::AO__atomic_compare_exchange) 867 Val2 = EmitPointerWithAlignment(E->getVal2()); 868 else 869 Val2 = EmitValToTemp(*this, E->getVal2()); 870 OrderFail = EmitScalarExpr(E->getOrderFail()); 871 if (E->getOp() == AtomicExpr::AO__atomic_compare_exchange_n || 872 E->getOp() == AtomicExpr::AO__atomic_compare_exchange) 873 IsWeak = EmitScalarExpr(E->getWeak()); 874 break; 875 876 case AtomicExpr::AO__c11_atomic_fetch_add: 877 case AtomicExpr::AO__c11_atomic_fetch_sub: 878 case AtomicExpr::AO__opencl_atomic_fetch_add: 879 case AtomicExpr::AO__opencl_atomic_fetch_sub: 880 if (MemTy->isPointerType()) { 881 // For pointer arithmetic, we're required to do a bit of math: 882 // adding 1 to an int* is not the same as adding 1 to a uintptr_t. 883 // ... but only for the C11 builtins. The GNU builtins expect the 884 // user to multiply by sizeof(T). 885 QualType Val1Ty = E->getVal1()->getType(); 886 llvm::Value *Val1Scalar = EmitScalarExpr(E->getVal1()); 887 CharUnits PointeeIncAmt = 888 getContext().getTypeSizeInChars(MemTy->getPointeeType()); 889 Val1Scalar = Builder.CreateMul(Val1Scalar, CGM.getSize(PointeeIncAmt)); 890 auto Temp = CreateMemTemp(Val1Ty, ".atomictmp"); 891 Val1 = Temp; 892 EmitStoreOfScalar(Val1Scalar, MakeAddrLValue(Temp, Val1Ty)); 893 break; 894 } 895 LLVM_FALLTHROUGH; 896 case AtomicExpr::AO__atomic_fetch_add: 897 case AtomicExpr::AO__atomic_fetch_sub: 898 case AtomicExpr::AO__atomic_add_fetch: 899 case AtomicExpr::AO__atomic_sub_fetch: 900 case AtomicExpr::AO__c11_atomic_store: 901 case AtomicExpr::AO__c11_atomic_exchange: 902 case AtomicExpr::AO__opencl_atomic_store: 903 case AtomicExpr::AO__opencl_atomic_exchange: 904 case AtomicExpr::AO__atomic_store_n: 905 case AtomicExpr::AO__atomic_exchange_n: 906 case AtomicExpr::AO__c11_atomic_fetch_and: 907 case AtomicExpr::AO__c11_atomic_fetch_or: 908 case AtomicExpr::AO__c11_atomic_fetch_xor: 909 case AtomicExpr::AO__c11_atomic_fetch_max: 910 case AtomicExpr::AO__c11_atomic_fetch_min: 911 case AtomicExpr::AO__opencl_atomic_fetch_and: 912 case AtomicExpr::AO__opencl_atomic_fetch_or: 913 case AtomicExpr::AO__opencl_atomic_fetch_xor: 914 case AtomicExpr::AO__opencl_atomic_fetch_min: 915 case AtomicExpr::AO__opencl_atomic_fetch_max: 916 case AtomicExpr::AO__atomic_fetch_and: 917 case AtomicExpr::AO__atomic_fetch_or: 918 case AtomicExpr::AO__atomic_fetch_xor: 919 case AtomicExpr::AO__atomic_fetch_nand: 920 case AtomicExpr::AO__atomic_and_fetch: 921 case AtomicExpr::AO__atomic_or_fetch: 922 case AtomicExpr::AO__atomic_xor_fetch: 923 case AtomicExpr::AO__atomic_nand_fetch: 924 case AtomicExpr::AO__atomic_max_fetch: 925 case AtomicExpr::AO__atomic_min_fetch: 926 case AtomicExpr::AO__atomic_fetch_max: 927 case AtomicExpr::AO__atomic_fetch_min: 928 Val1 = EmitValToTemp(*this, E->getVal1()); 929 break; 930 } 931 932 QualType RValTy = E->getType().getUnqualifiedType(); 933 934 // The inlined atomics only function on iN types, where N is a power of 2. We 935 // need to make sure (via temporaries if necessary) that all incoming values 936 // are compatible. 937 LValue AtomicVal = MakeAddrLValue(Ptr, AtomicTy); 938 AtomicInfo Atomics(*this, AtomicVal); 939 940 Ptr = Atomics.emitCastToAtomicIntPointer(Ptr); 941 if (Val1.isValid()) Val1 = Atomics.convertToAtomicIntPointer(Val1); 942 if (Val2.isValid()) Val2 = Atomics.convertToAtomicIntPointer(Val2); 943 if (Dest.isValid()) 944 Dest = Atomics.emitCastToAtomicIntPointer(Dest); 945 else if (E->isCmpXChg()) 946 Dest = CreateMemTemp(RValTy, "cmpxchg.bool"); 947 else if (!RValTy->isVoidType()) 948 Dest = Atomics.emitCastToAtomicIntPointer(Atomics.CreateTempAlloca()); 949 950 // Use a library call. See: http://gcc.gnu.org/wiki/Atomic/GCCMM/LIbrary . 951 if (UseLibcall) { 952 bool UseOptimizedLibcall = false; 953 switch (E->getOp()) { 954 case AtomicExpr::AO__c11_atomic_init: 955 case AtomicExpr::AO__opencl_atomic_init: 956 llvm_unreachable("Already handled above with EmitAtomicInit!"); 957 958 case AtomicExpr::AO__c11_atomic_fetch_add: 959 case AtomicExpr::AO__opencl_atomic_fetch_add: 960 case AtomicExpr::AO__atomic_fetch_add: 961 case AtomicExpr::AO__c11_atomic_fetch_and: 962 case AtomicExpr::AO__opencl_atomic_fetch_and: 963 case AtomicExpr::AO__atomic_fetch_and: 964 case AtomicExpr::AO__c11_atomic_fetch_or: 965 case AtomicExpr::AO__opencl_atomic_fetch_or: 966 case AtomicExpr::AO__atomic_fetch_or: 967 case AtomicExpr::AO__atomic_fetch_nand: 968 case AtomicExpr::AO__c11_atomic_fetch_sub: 969 case AtomicExpr::AO__opencl_atomic_fetch_sub: 970 case AtomicExpr::AO__atomic_fetch_sub: 971 case AtomicExpr::AO__c11_atomic_fetch_xor: 972 case AtomicExpr::AO__opencl_atomic_fetch_xor: 973 case AtomicExpr::AO__opencl_atomic_fetch_min: 974 case AtomicExpr::AO__opencl_atomic_fetch_max: 975 case AtomicExpr::AO__atomic_fetch_xor: 976 case AtomicExpr::AO__c11_atomic_fetch_max: 977 case AtomicExpr::AO__c11_atomic_fetch_min: 978 case AtomicExpr::AO__atomic_add_fetch: 979 case AtomicExpr::AO__atomic_and_fetch: 980 case AtomicExpr::AO__atomic_nand_fetch: 981 case AtomicExpr::AO__atomic_or_fetch: 982 case AtomicExpr::AO__atomic_sub_fetch: 983 case AtomicExpr::AO__atomic_xor_fetch: 984 case AtomicExpr::AO__atomic_fetch_max: 985 case AtomicExpr::AO__atomic_fetch_min: 986 case AtomicExpr::AO__atomic_max_fetch: 987 case AtomicExpr::AO__atomic_min_fetch: 988 // For these, only library calls for certain sizes exist. 989 UseOptimizedLibcall = true; 990 break; 991 992 case AtomicExpr::AO__atomic_load: 993 case AtomicExpr::AO__atomic_store: 994 case AtomicExpr::AO__atomic_exchange: 995 case AtomicExpr::AO__atomic_compare_exchange: 996 // Use the generic version if we don't know that the operand will be 997 // suitably aligned for the optimized version. 998 if (Misaligned) 999 break; 1000 LLVM_FALLTHROUGH; 1001 case AtomicExpr::AO__c11_atomic_load: 1002 case AtomicExpr::AO__c11_atomic_store: 1003 case AtomicExpr::AO__c11_atomic_exchange: 1004 case AtomicExpr::AO__c11_atomic_compare_exchange_weak: 1005 case AtomicExpr::AO__c11_atomic_compare_exchange_strong: 1006 case AtomicExpr::AO__opencl_atomic_load: 1007 case AtomicExpr::AO__opencl_atomic_store: 1008 case AtomicExpr::AO__opencl_atomic_exchange: 1009 case AtomicExpr::AO__opencl_atomic_compare_exchange_weak: 1010 case AtomicExpr::AO__opencl_atomic_compare_exchange_strong: 1011 case AtomicExpr::AO__atomic_load_n: 1012 case AtomicExpr::AO__atomic_store_n: 1013 case AtomicExpr::AO__atomic_exchange_n: 1014 case AtomicExpr::AO__atomic_compare_exchange_n: 1015 // Only use optimized library calls for sizes for which they exist. 1016 // FIXME: Size == 16 optimized library functions exist too. 1017 if (Size == 1 || Size == 2 || Size == 4 || Size == 8) 1018 UseOptimizedLibcall = true; 1019 break; 1020 } 1021 1022 CallArgList Args; 1023 if (!UseOptimizedLibcall) { 1024 // For non-optimized library calls, the size is the first parameter 1025 Args.add(RValue::get(llvm::ConstantInt::get(SizeTy, Size)), 1026 getContext().getSizeType()); 1027 } 1028 // Atomic address is the first or second parameter 1029 // The OpenCL atomic library functions only accept pointer arguments to 1030 // generic address space. 1031 auto CastToGenericAddrSpace = [&](llvm::Value *V, QualType PT) { 1032 if (!E->isOpenCL()) 1033 return V; 1034 auto AS = PT->castAs<PointerType>()->getPointeeType().getAddressSpace(); 1035 if (AS == LangAS::opencl_generic) 1036 return V; 1037 auto DestAS = getContext().getTargetAddressSpace(LangAS::opencl_generic); 1038 auto T = V->getType(); 1039 auto *DestType = T->getPointerElementType()->getPointerTo(DestAS); 1040 1041 return getTargetHooks().performAddrSpaceCast( 1042 *this, V, AS, LangAS::opencl_generic, DestType, false); 1043 }; 1044 1045 Args.add(RValue::get(CastToGenericAddrSpace( 1046 EmitCastToVoidPtr(Ptr.getPointer()), E->getPtr()->getType())), 1047 getContext().VoidPtrTy); 1048 1049 std::string LibCallName; 1050 QualType LoweredMemTy = 1051 MemTy->isPointerType() ? getContext().getIntPtrType() : MemTy; 1052 QualType RetTy; 1053 bool HaveRetTy = false; 1054 llvm::Instruction::BinaryOps PostOp = (llvm::Instruction::BinaryOps)0; 1055 bool PostOpMinMax = false; 1056 switch (E->getOp()) { 1057 case AtomicExpr::AO__c11_atomic_init: 1058 case AtomicExpr::AO__opencl_atomic_init: 1059 llvm_unreachable("Already handled!"); 1060 1061 // There is only one libcall for compare an exchange, because there is no 1062 // optimisation benefit possible from a libcall version of a weak compare 1063 // and exchange. 1064 // bool __atomic_compare_exchange(size_t size, void *mem, void *expected, 1065 // void *desired, int success, int failure) 1066 // bool __atomic_compare_exchange_N(T *mem, T *expected, T desired, 1067 // int success, int failure) 1068 case AtomicExpr::AO__c11_atomic_compare_exchange_weak: 1069 case AtomicExpr::AO__c11_atomic_compare_exchange_strong: 1070 case AtomicExpr::AO__opencl_atomic_compare_exchange_weak: 1071 case AtomicExpr::AO__opencl_atomic_compare_exchange_strong: 1072 case AtomicExpr::AO__atomic_compare_exchange: 1073 case AtomicExpr::AO__atomic_compare_exchange_n: 1074 LibCallName = "__atomic_compare_exchange"; 1075 RetTy = getContext().BoolTy; 1076 HaveRetTy = true; 1077 Args.add( 1078 RValue::get(CastToGenericAddrSpace( 1079 EmitCastToVoidPtr(Val1.getPointer()), E->getVal1()->getType())), 1080 getContext().VoidPtrTy); 1081 AddDirectArgument(*this, Args, UseOptimizedLibcall, Val2.getPointer(), 1082 MemTy, E->getExprLoc(), TInfo.Width); 1083 Args.add(RValue::get(Order), getContext().IntTy); 1084 Order = OrderFail; 1085 break; 1086 // void __atomic_exchange(size_t size, void *mem, void *val, void *return, 1087 // int order) 1088 // T __atomic_exchange_N(T *mem, T val, int order) 1089 case AtomicExpr::AO__c11_atomic_exchange: 1090 case AtomicExpr::AO__opencl_atomic_exchange: 1091 case AtomicExpr::AO__atomic_exchange_n: 1092 case AtomicExpr::AO__atomic_exchange: 1093 LibCallName = "__atomic_exchange"; 1094 AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(), 1095 MemTy, E->getExprLoc(), TInfo.Width); 1096 break; 1097 // void __atomic_store(size_t size, void *mem, void *val, int order) 1098 // void __atomic_store_N(T *mem, T val, int order) 1099 case AtomicExpr::AO__c11_atomic_store: 1100 case AtomicExpr::AO__opencl_atomic_store: 1101 case AtomicExpr::AO__atomic_store: 1102 case AtomicExpr::AO__atomic_store_n: 1103 LibCallName = "__atomic_store"; 1104 RetTy = getContext().VoidTy; 1105 HaveRetTy = true; 1106 AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(), 1107 MemTy, E->getExprLoc(), TInfo.Width); 1108 break; 1109 // void __atomic_load(size_t size, void *mem, void *return, int order) 1110 // T __atomic_load_N(T *mem, int order) 1111 case AtomicExpr::AO__c11_atomic_load: 1112 case AtomicExpr::AO__opencl_atomic_load: 1113 case AtomicExpr::AO__atomic_load: 1114 case AtomicExpr::AO__atomic_load_n: 1115 LibCallName = "__atomic_load"; 1116 break; 1117 // T __atomic_add_fetch_N(T *mem, T val, int order) 1118 // T __atomic_fetch_add_N(T *mem, T val, int order) 1119 case AtomicExpr::AO__atomic_add_fetch: 1120 PostOp = llvm::Instruction::Add; 1121 LLVM_FALLTHROUGH; 1122 case AtomicExpr::AO__c11_atomic_fetch_add: 1123 case AtomicExpr::AO__opencl_atomic_fetch_add: 1124 case AtomicExpr::AO__atomic_fetch_add: 1125 LibCallName = "__atomic_fetch_add"; 1126 AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(), 1127 LoweredMemTy, E->getExprLoc(), TInfo.Width); 1128 break; 1129 // T __atomic_and_fetch_N(T *mem, T val, int order) 1130 // T __atomic_fetch_and_N(T *mem, T val, int order) 1131 case AtomicExpr::AO__atomic_and_fetch: 1132 PostOp = llvm::Instruction::And; 1133 LLVM_FALLTHROUGH; 1134 case AtomicExpr::AO__c11_atomic_fetch_and: 1135 case AtomicExpr::AO__opencl_atomic_fetch_and: 1136 case AtomicExpr::AO__atomic_fetch_and: 1137 LibCallName = "__atomic_fetch_and"; 1138 AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(), 1139 MemTy, E->getExprLoc(), TInfo.Width); 1140 break; 1141 // T __atomic_or_fetch_N(T *mem, T val, int order) 1142 // T __atomic_fetch_or_N(T *mem, T val, int order) 1143 case AtomicExpr::AO__atomic_or_fetch: 1144 PostOp = llvm::Instruction::Or; 1145 LLVM_FALLTHROUGH; 1146 case AtomicExpr::AO__c11_atomic_fetch_or: 1147 case AtomicExpr::AO__opencl_atomic_fetch_or: 1148 case AtomicExpr::AO__atomic_fetch_or: 1149 LibCallName = "__atomic_fetch_or"; 1150 AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(), 1151 MemTy, E->getExprLoc(), TInfo.Width); 1152 break; 1153 // T __atomic_sub_fetch_N(T *mem, T val, int order) 1154 // T __atomic_fetch_sub_N(T *mem, T val, int order) 1155 case AtomicExpr::AO__atomic_sub_fetch: 1156 PostOp = llvm::Instruction::Sub; 1157 LLVM_FALLTHROUGH; 1158 case AtomicExpr::AO__c11_atomic_fetch_sub: 1159 case AtomicExpr::AO__opencl_atomic_fetch_sub: 1160 case AtomicExpr::AO__atomic_fetch_sub: 1161 LibCallName = "__atomic_fetch_sub"; 1162 AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(), 1163 LoweredMemTy, E->getExprLoc(), TInfo.Width); 1164 break; 1165 // T __atomic_xor_fetch_N(T *mem, T val, int order) 1166 // T __atomic_fetch_xor_N(T *mem, T val, int order) 1167 case AtomicExpr::AO__atomic_xor_fetch: 1168 PostOp = llvm::Instruction::Xor; 1169 LLVM_FALLTHROUGH; 1170 case AtomicExpr::AO__c11_atomic_fetch_xor: 1171 case AtomicExpr::AO__opencl_atomic_fetch_xor: 1172 case AtomicExpr::AO__atomic_fetch_xor: 1173 LibCallName = "__atomic_fetch_xor"; 1174 AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(), 1175 MemTy, E->getExprLoc(), TInfo.Width); 1176 break; 1177 case AtomicExpr::AO__atomic_min_fetch: 1178 PostOpMinMax = true; 1179 LLVM_FALLTHROUGH; 1180 case AtomicExpr::AO__c11_atomic_fetch_min: 1181 case AtomicExpr::AO__atomic_fetch_min: 1182 case AtomicExpr::AO__opencl_atomic_fetch_min: 1183 LibCallName = E->getValueType()->isSignedIntegerType() 1184 ? "__atomic_fetch_min" 1185 : "__atomic_fetch_umin"; 1186 AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(), 1187 LoweredMemTy, E->getExprLoc(), TInfo.Width); 1188 break; 1189 case AtomicExpr::AO__atomic_max_fetch: 1190 PostOpMinMax = true; 1191 LLVM_FALLTHROUGH; 1192 case AtomicExpr::AO__c11_atomic_fetch_max: 1193 case AtomicExpr::AO__atomic_fetch_max: 1194 case AtomicExpr::AO__opencl_atomic_fetch_max: 1195 LibCallName = E->getValueType()->isSignedIntegerType() 1196 ? "__atomic_fetch_max" 1197 : "__atomic_fetch_umax"; 1198 AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(), 1199 LoweredMemTy, E->getExprLoc(), TInfo.Width); 1200 break; 1201 // T __atomic_nand_fetch_N(T *mem, T val, int order) 1202 // T __atomic_fetch_nand_N(T *mem, T val, int order) 1203 case AtomicExpr::AO__atomic_nand_fetch: 1204 PostOp = llvm::Instruction::And; // the NOT is special cased below 1205 LLVM_FALLTHROUGH; 1206 case AtomicExpr::AO__atomic_fetch_nand: 1207 LibCallName = "__atomic_fetch_nand"; 1208 AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(), 1209 MemTy, E->getExprLoc(), TInfo.Width); 1210 break; 1211 } 1212 1213 if (E->isOpenCL()) { 1214 LibCallName = std::string("__opencl") + 1215 StringRef(LibCallName).drop_front(1).str(); 1216 1217 } 1218 // Optimized functions have the size in their name. 1219 if (UseOptimizedLibcall) 1220 LibCallName += "_" + llvm::utostr(Size); 1221 // By default, assume we return a value of the atomic type. 1222 if (!HaveRetTy) { 1223 if (UseOptimizedLibcall) { 1224 // Value is returned directly. 1225 // The function returns an appropriately sized integer type. 1226 RetTy = getContext().getIntTypeForBitwidth( 1227 getContext().toBits(TInfo.Width), /*Signed=*/false); 1228 } else { 1229 // Value is returned through parameter before the order. 1230 RetTy = getContext().VoidTy; 1231 Args.add(RValue::get(EmitCastToVoidPtr(Dest.getPointer())), 1232 getContext().VoidPtrTy); 1233 } 1234 } 1235 // order is always the last parameter 1236 Args.add(RValue::get(Order), 1237 getContext().IntTy); 1238 if (E->isOpenCL()) 1239 Args.add(RValue::get(Scope), getContext().IntTy); 1240 1241 // PostOp is only needed for the atomic_*_fetch operations, and 1242 // thus is only needed for and implemented in the 1243 // UseOptimizedLibcall codepath. 1244 assert(UseOptimizedLibcall || (!PostOp && !PostOpMinMax)); 1245 1246 RValue Res = emitAtomicLibcall(*this, LibCallName, RetTy, Args); 1247 // The value is returned directly from the libcall. 1248 if (E->isCmpXChg()) 1249 return Res; 1250 1251 // The value is returned directly for optimized libcalls but the expr 1252 // provided an out-param. 1253 if (UseOptimizedLibcall && Res.getScalarVal()) { 1254 llvm::Value *ResVal = Res.getScalarVal(); 1255 if (PostOpMinMax) { 1256 llvm::Value *LoadVal1 = Args[1].getRValue(*this).getScalarVal(); 1257 ResVal = EmitPostAtomicMinMax(Builder, E->getOp(), 1258 E->getValueType()->isSignedIntegerType(), 1259 ResVal, LoadVal1); 1260 } else if (PostOp) { 1261 llvm::Value *LoadVal1 = Args[1].getRValue(*this).getScalarVal(); 1262 ResVal = Builder.CreateBinOp(PostOp, ResVal, LoadVal1); 1263 } 1264 if (E->getOp() == AtomicExpr::AO__atomic_nand_fetch) 1265 ResVal = Builder.CreateNot(ResVal); 1266 1267 Builder.CreateStore( 1268 ResVal, 1269 Builder.CreateBitCast(Dest, ResVal->getType()->getPointerTo())); 1270 } 1271 1272 if (RValTy->isVoidType()) 1273 return RValue::get(nullptr); 1274 1275 return convertTempToRValue( 1276 Builder.CreateBitCast(Dest, ConvertTypeForMem(RValTy)->getPointerTo()), 1277 RValTy, E->getExprLoc()); 1278 } 1279 1280 bool IsStore = E->getOp() == AtomicExpr::AO__c11_atomic_store || 1281 E->getOp() == AtomicExpr::AO__opencl_atomic_store || 1282 E->getOp() == AtomicExpr::AO__atomic_store || 1283 E->getOp() == AtomicExpr::AO__atomic_store_n; 1284 bool IsLoad = E->getOp() == AtomicExpr::AO__c11_atomic_load || 1285 E->getOp() == AtomicExpr::AO__opencl_atomic_load || 1286 E->getOp() == AtomicExpr::AO__atomic_load || 1287 E->getOp() == AtomicExpr::AO__atomic_load_n; 1288 1289 if (isa<llvm::ConstantInt>(Order)) { 1290 auto ord = cast<llvm::ConstantInt>(Order)->getZExtValue(); 1291 // We should not ever get to a case where the ordering isn't a valid C ABI 1292 // value, but it's hard to enforce that in general. 1293 if (llvm::isValidAtomicOrderingCABI(ord)) 1294 switch ((llvm::AtomicOrderingCABI)ord) { 1295 case llvm::AtomicOrderingCABI::relaxed: 1296 EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size, 1297 llvm::AtomicOrdering::Monotonic, Scope); 1298 break; 1299 case llvm::AtomicOrderingCABI::consume: 1300 case llvm::AtomicOrderingCABI::acquire: 1301 if (IsStore) 1302 break; // Avoid crashing on code with undefined behavior 1303 EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size, 1304 llvm::AtomicOrdering::Acquire, Scope); 1305 break; 1306 case llvm::AtomicOrderingCABI::release: 1307 if (IsLoad) 1308 break; // Avoid crashing on code with undefined behavior 1309 EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size, 1310 llvm::AtomicOrdering::Release, Scope); 1311 break; 1312 case llvm::AtomicOrderingCABI::acq_rel: 1313 if (IsLoad || IsStore) 1314 break; // Avoid crashing on code with undefined behavior 1315 EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size, 1316 llvm::AtomicOrdering::AcquireRelease, Scope); 1317 break; 1318 case llvm::AtomicOrderingCABI::seq_cst: 1319 EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size, 1320 llvm::AtomicOrdering::SequentiallyConsistent, Scope); 1321 break; 1322 } 1323 if (RValTy->isVoidType()) 1324 return RValue::get(nullptr); 1325 1326 return convertTempToRValue( 1327 Builder.CreateBitCast(Dest, ConvertTypeForMem(RValTy)->getPointerTo( 1328 Dest.getAddressSpace())), 1329 RValTy, E->getExprLoc()); 1330 } 1331 1332 // Long case, when Order isn't obviously constant. 1333 1334 // Create all the relevant BB's 1335 llvm::BasicBlock *MonotonicBB = nullptr, *AcquireBB = nullptr, 1336 *ReleaseBB = nullptr, *AcqRelBB = nullptr, 1337 *SeqCstBB = nullptr; 1338 MonotonicBB = createBasicBlock("monotonic", CurFn); 1339 if (!IsStore) 1340 AcquireBB = createBasicBlock("acquire", CurFn); 1341 if (!IsLoad) 1342 ReleaseBB = createBasicBlock("release", CurFn); 1343 if (!IsLoad && !IsStore) 1344 AcqRelBB = createBasicBlock("acqrel", CurFn); 1345 SeqCstBB = createBasicBlock("seqcst", CurFn); 1346 llvm::BasicBlock *ContBB = createBasicBlock("atomic.continue", CurFn); 1347 1348 // Create the switch for the split 1349 // MonotonicBB is arbitrarily chosen as the default case; in practice, this 1350 // doesn't matter unless someone is crazy enough to use something that 1351 // doesn't fold to a constant for the ordering. 1352 Order = Builder.CreateIntCast(Order, Builder.getInt32Ty(), false); 1353 llvm::SwitchInst *SI = Builder.CreateSwitch(Order, MonotonicBB); 1354 1355 // Emit all the different atomics 1356 Builder.SetInsertPoint(MonotonicBB); 1357 EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size, 1358 llvm::AtomicOrdering::Monotonic, Scope); 1359 Builder.CreateBr(ContBB); 1360 if (!IsStore) { 1361 Builder.SetInsertPoint(AcquireBB); 1362 EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size, 1363 llvm::AtomicOrdering::Acquire, Scope); 1364 Builder.CreateBr(ContBB); 1365 SI->addCase(Builder.getInt32((int)llvm::AtomicOrderingCABI::consume), 1366 AcquireBB); 1367 SI->addCase(Builder.getInt32((int)llvm::AtomicOrderingCABI::acquire), 1368 AcquireBB); 1369 } 1370 if (!IsLoad) { 1371 Builder.SetInsertPoint(ReleaseBB); 1372 EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size, 1373 llvm::AtomicOrdering::Release, Scope); 1374 Builder.CreateBr(ContBB); 1375 SI->addCase(Builder.getInt32((int)llvm::AtomicOrderingCABI::release), 1376 ReleaseBB); 1377 } 1378 if (!IsLoad && !IsStore) { 1379 Builder.SetInsertPoint(AcqRelBB); 1380 EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size, 1381 llvm::AtomicOrdering::AcquireRelease, Scope); 1382 Builder.CreateBr(ContBB); 1383 SI->addCase(Builder.getInt32((int)llvm::AtomicOrderingCABI::acq_rel), 1384 AcqRelBB); 1385 } 1386 Builder.SetInsertPoint(SeqCstBB); 1387 EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size, 1388 llvm::AtomicOrdering::SequentiallyConsistent, Scope); 1389 Builder.CreateBr(ContBB); 1390 SI->addCase(Builder.getInt32((int)llvm::AtomicOrderingCABI::seq_cst), 1391 SeqCstBB); 1392 1393 // Cleanup and return 1394 Builder.SetInsertPoint(ContBB); 1395 if (RValTy->isVoidType()) 1396 return RValue::get(nullptr); 1397 1398 assert(Atomics.getValueSizeInBits() <= Atomics.getAtomicSizeInBits()); 1399 return convertTempToRValue( 1400 Builder.CreateBitCast(Dest, ConvertTypeForMem(RValTy)->getPointerTo( 1401 Dest.getAddressSpace())), 1402 RValTy, E->getExprLoc()); 1403 } 1404 1405 Address AtomicInfo::emitCastToAtomicIntPointer(Address addr) const { 1406 unsigned addrspace = 1407 cast<llvm::PointerType>(addr.getPointer()->getType())->getAddressSpace(); 1408 llvm::IntegerType *ty = 1409 llvm::IntegerType::get(CGF.getLLVMContext(), AtomicSizeInBits); 1410 return CGF.Builder.CreateBitCast(addr, ty->getPointerTo(addrspace)); 1411 } 1412 1413 Address AtomicInfo::convertToAtomicIntPointer(Address Addr) const { 1414 llvm::Type *Ty = Addr.getElementType(); 1415 uint64_t SourceSizeInBits = CGF.CGM.getDataLayout().getTypeSizeInBits(Ty); 1416 if (SourceSizeInBits != AtomicSizeInBits) { 1417 Address Tmp = CreateTempAlloca(); 1418 CGF.Builder.CreateMemCpy(Tmp, Addr, 1419 std::min(AtomicSizeInBits, SourceSizeInBits) / 8); 1420 Addr = Tmp; 1421 } 1422 1423 return emitCastToAtomicIntPointer(Addr); 1424 } 1425 1426 RValue AtomicInfo::convertAtomicTempToRValue(Address addr, 1427 AggValueSlot resultSlot, 1428 SourceLocation loc, 1429 bool asValue) const { 1430 if (LVal.isSimple()) { 1431 if (EvaluationKind == TEK_Aggregate) 1432 return resultSlot.asRValue(); 1433 1434 // Drill into the padding structure if we have one. 1435 if (hasPadding()) 1436 addr = CGF.Builder.CreateStructGEP(addr, 0); 1437 1438 // Otherwise, just convert the temporary to an r-value using the 1439 // normal conversion routine. 1440 return CGF.convertTempToRValue(addr, getValueType(), loc); 1441 } 1442 if (!asValue) 1443 // Get RValue from temp memory as atomic for non-simple lvalues 1444 return RValue::get(CGF.Builder.CreateLoad(addr)); 1445 if (LVal.isBitField()) 1446 return CGF.EmitLoadOfBitfieldLValue( 1447 LValue::MakeBitfield(addr, LVal.getBitFieldInfo(), LVal.getType(), 1448 LVal.getBaseInfo(), TBAAAccessInfo()), loc); 1449 if (LVal.isVectorElt()) 1450 return CGF.EmitLoadOfLValue( 1451 LValue::MakeVectorElt(addr, LVal.getVectorIdx(), LVal.getType(), 1452 LVal.getBaseInfo(), TBAAAccessInfo()), loc); 1453 assert(LVal.isExtVectorElt()); 1454 return CGF.EmitLoadOfExtVectorElementLValue(LValue::MakeExtVectorElt( 1455 addr, LVal.getExtVectorElts(), LVal.getType(), 1456 LVal.getBaseInfo(), TBAAAccessInfo())); 1457 } 1458 1459 RValue AtomicInfo::ConvertIntToValueOrAtomic(llvm::Value *IntVal, 1460 AggValueSlot ResultSlot, 1461 SourceLocation Loc, 1462 bool AsValue) const { 1463 // Try not to in some easy cases. 1464 assert(IntVal->getType()->isIntegerTy() && "Expected integer value"); 1465 if (getEvaluationKind() == TEK_Scalar && 1466 (((!LVal.isBitField() || 1467 LVal.getBitFieldInfo().Size == ValueSizeInBits) && 1468 !hasPadding()) || 1469 !AsValue)) { 1470 auto *ValTy = AsValue 1471 ? CGF.ConvertTypeForMem(ValueTy) 1472 : getAtomicAddress().getType()->getPointerElementType(); 1473 if (ValTy->isIntegerTy()) { 1474 assert(IntVal->getType() == ValTy && "Different integer types."); 1475 return RValue::get(CGF.EmitFromMemory(IntVal, ValueTy)); 1476 } else if (ValTy->isPointerTy()) 1477 return RValue::get(CGF.Builder.CreateIntToPtr(IntVal, ValTy)); 1478 else if (llvm::CastInst::isBitCastable(IntVal->getType(), ValTy)) 1479 return RValue::get(CGF.Builder.CreateBitCast(IntVal, ValTy)); 1480 } 1481 1482 // Create a temporary. This needs to be big enough to hold the 1483 // atomic integer. 1484 Address Temp = Address::invalid(); 1485 bool TempIsVolatile = false; 1486 if (AsValue && getEvaluationKind() == TEK_Aggregate) { 1487 assert(!ResultSlot.isIgnored()); 1488 Temp = ResultSlot.getAddress(); 1489 TempIsVolatile = ResultSlot.isVolatile(); 1490 } else { 1491 Temp = CreateTempAlloca(); 1492 } 1493 1494 // Slam the integer into the temporary. 1495 Address CastTemp = emitCastToAtomicIntPointer(Temp); 1496 CGF.Builder.CreateStore(IntVal, CastTemp) 1497 ->setVolatile(TempIsVolatile); 1498 1499 return convertAtomicTempToRValue(Temp, ResultSlot, Loc, AsValue); 1500 } 1501 1502 void AtomicInfo::EmitAtomicLoadLibcall(llvm::Value *AddForLoaded, 1503 llvm::AtomicOrdering AO, bool) { 1504 // void __atomic_load(size_t size, void *mem, void *return, int order); 1505 CallArgList Args; 1506 Args.add(RValue::get(getAtomicSizeValue()), CGF.getContext().getSizeType()); 1507 Args.add(RValue::get(CGF.EmitCastToVoidPtr(getAtomicPointer())), 1508 CGF.getContext().VoidPtrTy); 1509 Args.add(RValue::get(CGF.EmitCastToVoidPtr(AddForLoaded)), 1510 CGF.getContext().VoidPtrTy); 1511 Args.add( 1512 RValue::get(llvm::ConstantInt::get(CGF.IntTy, (int)llvm::toCABI(AO))), 1513 CGF.getContext().IntTy); 1514 emitAtomicLibcall(CGF, "__atomic_load", CGF.getContext().VoidTy, Args); 1515 } 1516 1517 llvm::Value *AtomicInfo::EmitAtomicLoadOp(llvm::AtomicOrdering AO, 1518 bool IsVolatile) { 1519 // Okay, we're doing this natively. 1520 Address Addr = getAtomicAddressAsAtomicIntPointer(); 1521 llvm::LoadInst *Load = CGF.Builder.CreateLoad(Addr, "atomic-load"); 1522 Load->setAtomic(AO); 1523 1524 // Other decoration. 1525 if (IsVolatile) 1526 Load->setVolatile(true); 1527 CGF.CGM.DecorateInstructionWithTBAA(Load, LVal.getTBAAInfo()); 1528 return Load; 1529 } 1530 1531 /// An LValue is a candidate for having its loads and stores be made atomic if 1532 /// we are operating under /volatile:ms *and* the LValue itself is volatile and 1533 /// performing such an operation can be performed without a libcall. 1534 bool CodeGenFunction::LValueIsSuitableForInlineAtomic(LValue LV) { 1535 if (!CGM.getCodeGenOpts().MSVolatile) return false; 1536 AtomicInfo AI(*this, LV); 1537 bool IsVolatile = LV.isVolatile() || hasVolatileMember(LV.getType()); 1538 // An atomic is inline if we don't need to use a libcall. 1539 bool AtomicIsInline = !AI.shouldUseLibcall(); 1540 // MSVC doesn't seem to do this for types wider than a pointer. 1541 if (getContext().getTypeSize(LV.getType()) > 1542 getContext().getTypeSize(getContext().getIntPtrType())) 1543 return false; 1544 return IsVolatile && AtomicIsInline; 1545 } 1546 1547 RValue CodeGenFunction::EmitAtomicLoad(LValue LV, SourceLocation SL, 1548 AggValueSlot Slot) { 1549 llvm::AtomicOrdering AO; 1550 bool IsVolatile = LV.isVolatileQualified(); 1551 if (LV.getType()->isAtomicType()) { 1552 AO = llvm::AtomicOrdering::SequentiallyConsistent; 1553 } else { 1554 AO = llvm::AtomicOrdering::Acquire; 1555 IsVolatile = true; 1556 } 1557 return EmitAtomicLoad(LV, SL, AO, IsVolatile, Slot); 1558 } 1559 1560 RValue AtomicInfo::EmitAtomicLoad(AggValueSlot ResultSlot, SourceLocation Loc, 1561 bool AsValue, llvm::AtomicOrdering AO, 1562 bool IsVolatile) { 1563 // Check whether we should use a library call. 1564 if (shouldUseLibcall()) { 1565 Address TempAddr = Address::invalid(); 1566 if (LVal.isSimple() && !ResultSlot.isIgnored()) { 1567 assert(getEvaluationKind() == TEK_Aggregate); 1568 TempAddr = ResultSlot.getAddress(); 1569 } else 1570 TempAddr = CreateTempAlloca(); 1571 1572 EmitAtomicLoadLibcall(TempAddr.getPointer(), AO, IsVolatile); 1573 1574 // Okay, turn that back into the original value or whole atomic (for 1575 // non-simple lvalues) type. 1576 return convertAtomicTempToRValue(TempAddr, ResultSlot, Loc, AsValue); 1577 } 1578 1579 // Okay, we're doing this natively. 1580 auto *Load = EmitAtomicLoadOp(AO, IsVolatile); 1581 1582 // If we're ignoring an aggregate return, don't do anything. 1583 if (getEvaluationKind() == TEK_Aggregate && ResultSlot.isIgnored()) 1584 return RValue::getAggregate(Address::invalid(), false); 1585 1586 // Okay, turn that back into the original value or atomic (for non-simple 1587 // lvalues) type. 1588 return ConvertIntToValueOrAtomic(Load, ResultSlot, Loc, AsValue); 1589 } 1590 1591 /// Emit a load from an l-value of atomic type. Note that the r-value 1592 /// we produce is an r-value of the atomic *value* type. 1593 RValue CodeGenFunction::EmitAtomicLoad(LValue src, SourceLocation loc, 1594 llvm::AtomicOrdering AO, bool IsVolatile, 1595 AggValueSlot resultSlot) { 1596 AtomicInfo Atomics(*this, src); 1597 return Atomics.EmitAtomicLoad(resultSlot, loc, /*AsValue=*/true, AO, 1598 IsVolatile); 1599 } 1600 1601 /// Copy an r-value into memory as part of storing to an atomic type. 1602 /// This needs to create a bit-pattern suitable for atomic operations. 1603 void AtomicInfo::emitCopyIntoMemory(RValue rvalue) const { 1604 assert(LVal.isSimple()); 1605 // If we have an r-value, the rvalue should be of the atomic type, 1606 // which means that the caller is responsible for having zeroed 1607 // any padding. Just do an aggregate copy of that type. 1608 if (rvalue.isAggregate()) { 1609 LValue Dest = CGF.MakeAddrLValue(getAtomicAddress(), getAtomicType()); 1610 LValue Src = CGF.MakeAddrLValue(rvalue.getAggregateAddress(), 1611 getAtomicType()); 1612 bool IsVolatile = rvalue.isVolatileQualified() || 1613 LVal.isVolatileQualified(); 1614 CGF.EmitAggregateCopy(Dest, Src, getAtomicType(), 1615 AggValueSlot::DoesNotOverlap, IsVolatile); 1616 return; 1617 } 1618 1619 // Okay, otherwise we're copying stuff. 1620 1621 // Zero out the buffer if necessary. 1622 emitMemSetZeroIfNecessary(); 1623 1624 // Drill past the padding if present. 1625 LValue TempLVal = projectValue(); 1626 1627 // Okay, store the rvalue in. 1628 if (rvalue.isScalar()) { 1629 CGF.EmitStoreOfScalar(rvalue.getScalarVal(), TempLVal, /*init*/ true); 1630 } else { 1631 CGF.EmitStoreOfComplex(rvalue.getComplexVal(), TempLVal, /*init*/ true); 1632 } 1633 } 1634 1635 1636 /// Materialize an r-value into memory for the purposes of storing it 1637 /// to an atomic type. 1638 Address AtomicInfo::materializeRValue(RValue rvalue) const { 1639 // Aggregate r-values are already in memory, and EmitAtomicStore 1640 // requires them to be values of the atomic type. 1641 if (rvalue.isAggregate()) 1642 return rvalue.getAggregateAddress(); 1643 1644 // Otherwise, make a temporary and materialize into it. 1645 LValue TempLV = CGF.MakeAddrLValue(CreateTempAlloca(), getAtomicType()); 1646 AtomicInfo Atomics(CGF, TempLV); 1647 Atomics.emitCopyIntoMemory(rvalue); 1648 return TempLV.getAddress(CGF); 1649 } 1650 1651 llvm::Value *AtomicInfo::convertRValueToInt(RValue RVal) const { 1652 // If we've got a scalar value of the right size, try to avoid going 1653 // through memory. 1654 if (RVal.isScalar() && (!hasPadding() || !LVal.isSimple())) { 1655 llvm::Value *Value = RVal.getScalarVal(); 1656 if (isa<llvm::IntegerType>(Value->getType())) 1657 return CGF.EmitToMemory(Value, ValueTy); 1658 else { 1659 llvm::IntegerType *InputIntTy = llvm::IntegerType::get( 1660 CGF.getLLVMContext(), 1661 LVal.isSimple() ? getValueSizeInBits() : getAtomicSizeInBits()); 1662 if (isa<llvm::PointerType>(Value->getType())) 1663 return CGF.Builder.CreatePtrToInt(Value, InputIntTy); 1664 else if (llvm::BitCastInst::isBitCastable(Value->getType(), InputIntTy)) 1665 return CGF.Builder.CreateBitCast(Value, InputIntTy); 1666 } 1667 } 1668 // Otherwise, we need to go through memory. 1669 // Put the r-value in memory. 1670 Address Addr = materializeRValue(RVal); 1671 1672 // Cast the temporary to the atomic int type and pull a value out. 1673 Addr = emitCastToAtomicIntPointer(Addr); 1674 return CGF.Builder.CreateLoad(Addr); 1675 } 1676 1677 std::pair<llvm::Value *, llvm::Value *> AtomicInfo::EmitAtomicCompareExchangeOp( 1678 llvm::Value *ExpectedVal, llvm::Value *DesiredVal, 1679 llvm::AtomicOrdering Success, llvm::AtomicOrdering Failure, bool IsWeak) { 1680 // Do the atomic store. 1681 Address Addr = getAtomicAddressAsAtomicIntPointer(); 1682 auto *Inst = CGF.Builder.CreateAtomicCmpXchg(Addr.getPointer(), 1683 ExpectedVal, DesiredVal, 1684 Success, Failure); 1685 // Other decoration. 1686 Inst->setVolatile(LVal.isVolatileQualified()); 1687 Inst->setWeak(IsWeak); 1688 1689 // Okay, turn that back into the original value type. 1690 auto *PreviousVal = CGF.Builder.CreateExtractValue(Inst, /*Idxs=*/0); 1691 auto *SuccessFailureVal = CGF.Builder.CreateExtractValue(Inst, /*Idxs=*/1); 1692 return std::make_pair(PreviousVal, SuccessFailureVal); 1693 } 1694 1695 llvm::Value * 1696 AtomicInfo::EmitAtomicCompareExchangeLibcall(llvm::Value *ExpectedAddr, 1697 llvm::Value *DesiredAddr, 1698 llvm::AtomicOrdering Success, 1699 llvm::AtomicOrdering Failure) { 1700 // bool __atomic_compare_exchange(size_t size, void *obj, void *expected, 1701 // void *desired, int success, int failure); 1702 CallArgList Args; 1703 Args.add(RValue::get(getAtomicSizeValue()), CGF.getContext().getSizeType()); 1704 Args.add(RValue::get(CGF.EmitCastToVoidPtr(getAtomicPointer())), 1705 CGF.getContext().VoidPtrTy); 1706 Args.add(RValue::get(CGF.EmitCastToVoidPtr(ExpectedAddr)), 1707 CGF.getContext().VoidPtrTy); 1708 Args.add(RValue::get(CGF.EmitCastToVoidPtr(DesiredAddr)), 1709 CGF.getContext().VoidPtrTy); 1710 Args.add(RValue::get( 1711 llvm::ConstantInt::get(CGF.IntTy, (int)llvm::toCABI(Success))), 1712 CGF.getContext().IntTy); 1713 Args.add(RValue::get( 1714 llvm::ConstantInt::get(CGF.IntTy, (int)llvm::toCABI(Failure))), 1715 CGF.getContext().IntTy); 1716 auto SuccessFailureRVal = emitAtomicLibcall(CGF, "__atomic_compare_exchange", 1717 CGF.getContext().BoolTy, Args); 1718 1719 return SuccessFailureRVal.getScalarVal(); 1720 } 1721 1722 std::pair<RValue, llvm::Value *> AtomicInfo::EmitAtomicCompareExchange( 1723 RValue Expected, RValue Desired, llvm::AtomicOrdering Success, 1724 llvm::AtomicOrdering Failure, bool IsWeak) { 1725 if (isStrongerThan(Failure, Success)) 1726 // Don't assert on undefined behavior "failure argument shall be no stronger 1727 // than the success argument". 1728 Failure = llvm::AtomicCmpXchgInst::getStrongestFailureOrdering(Success); 1729 1730 // Check whether we should use a library call. 1731 if (shouldUseLibcall()) { 1732 // Produce a source address. 1733 Address ExpectedAddr = materializeRValue(Expected); 1734 Address DesiredAddr = materializeRValue(Desired); 1735 auto *Res = EmitAtomicCompareExchangeLibcall(ExpectedAddr.getPointer(), 1736 DesiredAddr.getPointer(), 1737 Success, Failure); 1738 return std::make_pair( 1739 convertAtomicTempToRValue(ExpectedAddr, AggValueSlot::ignored(), 1740 SourceLocation(), /*AsValue=*/false), 1741 Res); 1742 } 1743 1744 // If we've got a scalar value of the right size, try to avoid going 1745 // through memory. 1746 auto *ExpectedVal = convertRValueToInt(Expected); 1747 auto *DesiredVal = convertRValueToInt(Desired); 1748 auto Res = EmitAtomicCompareExchangeOp(ExpectedVal, DesiredVal, Success, 1749 Failure, IsWeak); 1750 return std::make_pair( 1751 ConvertIntToValueOrAtomic(Res.first, AggValueSlot::ignored(), 1752 SourceLocation(), /*AsValue=*/false), 1753 Res.second); 1754 } 1755 1756 static void 1757 EmitAtomicUpdateValue(CodeGenFunction &CGF, AtomicInfo &Atomics, RValue OldRVal, 1758 const llvm::function_ref<RValue(RValue)> &UpdateOp, 1759 Address DesiredAddr) { 1760 RValue UpRVal; 1761 LValue AtomicLVal = Atomics.getAtomicLValue(); 1762 LValue DesiredLVal; 1763 if (AtomicLVal.isSimple()) { 1764 UpRVal = OldRVal; 1765 DesiredLVal = CGF.MakeAddrLValue(DesiredAddr, AtomicLVal.getType()); 1766 } else { 1767 // Build new lvalue for temp address. 1768 Address Ptr = Atomics.materializeRValue(OldRVal); 1769 LValue UpdateLVal; 1770 if (AtomicLVal.isBitField()) { 1771 UpdateLVal = 1772 LValue::MakeBitfield(Ptr, AtomicLVal.getBitFieldInfo(), 1773 AtomicLVal.getType(), 1774 AtomicLVal.getBaseInfo(), 1775 AtomicLVal.getTBAAInfo()); 1776 DesiredLVal = 1777 LValue::MakeBitfield(DesiredAddr, AtomicLVal.getBitFieldInfo(), 1778 AtomicLVal.getType(), AtomicLVal.getBaseInfo(), 1779 AtomicLVal.getTBAAInfo()); 1780 } else if (AtomicLVal.isVectorElt()) { 1781 UpdateLVal = LValue::MakeVectorElt(Ptr, AtomicLVal.getVectorIdx(), 1782 AtomicLVal.getType(), 1783 AtomicLVal.getBaseInfo(), 1784 AtomicLVal.getTBAAInfo()); 1785 DesiredLVal = LValue::MakeVectorElt( 1786 DesiredAddr, AtomicLVal.getVectorIdx(), AtomicLVal.getType(), 1787 AtomicLVal.getBaseInfo(), AtomicLVal.getTBAAInfo()); 1788 } else { 1789 assert(AtomicLVal.isExtVectorElt()); 1790 UpdateLVal = LValue::MakeExtVectorElt(Ptr, AtomicLVal.getExtVectorElts(), 1791 AtomicLVal.getType(), 1792 AtomicLVal.getBaseInfo(), 1793 AtomicLVal.getTBAAInfo()); 1794 DesiredLVal = LValue::MakeExtVectorElt( 1795 DesiredAddr, AtomicLVal.getExtVectorElts(), AtomicLVal.getType(), 1796 AtomicLVal.getBaseInfo(), AtomicLVal.getTBAAInfo()); 1797 } 1798 UpRVal = CGF.EmitLoadOfLValue(UpdateLVal, SourceLocation()); 1799 } 1800 // Store new value in the corresponding memory area. 1801 RValue NewRVal = UpdateOp(UpRVal); 1802 if (NewRVal.isScalar()) { 1803 CGF.EmitStoreThroughLValue(NewRVal, DesiredLVal); 1804 } else { 1805 assert(NewRVal.isComplex()); 1806 CGF.EmitStoreOfComplex(NewRVal.getComplexVal(), DesiredLVal, 1807 /*isInit=*/false); 1808 } 1809 } 1810 1811 void AtomicInfo::EmitAtomicUpdateLibcall( 1812 llvm::AtomicOrdering AO, const llvm::function_ref<RValue(RValue)> &UpdateOp, 1813 bool IsVolatile) { 1814 auto Failure = llvm::AtomicCmpXchgInst::getStrongestFailureOrdering(AO); 1815 1816 Address ExpectedAddr = CreateTempAlloca(); 1817 1818 EmitAtomicLoadLibcall(ExpectedAddr.getPointer(), AO, IsVolatile); 1819 auto *ContBB = CGF.createBasicBlock("atomic_cont"); 1820 auto *ExitBB = CGF.createBasicBlock("atomic_exit"); 1821 CGF.EmitBlock(ContBB); 1822 Address DesiredAddr = CreateTempAlloca(); 1823 if ((LVal.isBitField() && BFI.Size != ValueSizeInBits) || 1824 requiresMemSetZero(getAtomicAddress().getElementType())) { 1825 auto *OldVal = CGF.Builder.CreateLoad(ExpectedAddr); 1826 CGF.Builder.CreateStore(OldVal, DesiredAddr); 1827 } 1828 auto OldRVal = convertAtomicTempToRValue(ExpectedAddr, 1829 AggValueSlot::ignored(), 1830 SourceLocation(), /*AsValue=*/false); 1831 EmitAtomicUpdateValue(CGF, *this, OldRVal, UpdateOp, DesiredAddr); 1832 auto *Res = 1833 EmitAtomicCompareExchangeLibcall(ExpectedAddr.getPointer(), 1834 DesiredAddr.getPointer(), 1835 AO, Failure); 1836 CGF.Builder.CreateCondBr(Res, ExitBB, ContBB); 1837 CGF.EmitBlock(ExitBB, /*IsFinished=*/true); 1838 } 1839 1840 void AtomicInfo::EmitAtomicUpdateOp( 1841 llvm::AtomicOrdering AO, const llvm::function_ref<RValue(RValue)> &UpdateOp, 1842 bool IsVolatile) { 1843 auto Failure = llvm::AtomicCmpXchgInst::getStrongestFailureOrdering(AO); 1844 1845 // Do the atomic load. 1846 auto *OldVal = EmitAtomicLoadOp(Failure, IsVolatile); 1847 // For non-simple lvalues perform compare-and-swap procedure. 1848 auto *ContBB = CGF.createBasicBlock("atomic_cont"); 1849 auto *ExitBB = CGF.createBasicBlock("atomic_exit"); 1850 auto *CurBB = CGF.Builder.GetInsertBlock(); 1851 CGF.EmitBlock(ContBB); 1852 llvm::PHINode *PHI = CGF.Builder.CreatePHI(OldVal->getType(), 1853 /*NumReservedValues=*/2); 1854 PHI->addIncoming(OldVal, CurBB); 1855 Address NewAtomicAddr = CreateTempAlloca(); 1856 Address NewAtomicIntAddr = emitCastToAtomicIntPointer(NewAtomicAddr); 1857 if ((LVal.isBitField() && BFI.Size != ValueSizeInBits) || 1858 requiresMemSetZero(getAtomicAddress().getElementType())) { 1859 CGF.Builder.CreateStore(PHI, NewAtomicIntAddr); 1860 } 1861 auto OldRVal = ConvertIntToValueOrAtomic(PHI, AggValueSlot::ignored(), 1862 SourceLocation(), /*AsValue=*/false); 1863 EmitAtomicUpdateValue(CGF, *this, OldRVal, UpdateOp, NewAtomicAddr); 1864 auto *DesiredVal = CGF.Builder.CreateLoad(NewAtomicIntAddr); 1865 // Try to write new value using cmpxchg operation. 1866 auto Res = EmitAtomicCompareExchangeOp(PHI, DesiredVal, AO, Failure); 1867 PHI->addIncoming(Res.first, CGF.Builder.GetInsertBlock()); 1868 CGF.Builder.CreateCondBr(Res.second, ExitBB, ContBB); 1869 CGF.EmitBlock(ExitBB, /*IsFinished=*/true); 1870 } 1871 1872 static void EmitAtomicUpdateValue(CodeGenFunction &CGF, AtomicInfo &Atomics, 1873 RValue UpdateRVal, Address DesiredAddr) { 1874 LValue AtomicLVal = Atomics.getAtomicLValue(); 1875 LValue DesiredLVal; 1876 // Build new lvalue for temp address. 1877 if (AtomicLVal.isBitField()) { 1878 DesiredLVal = 1879 LValue::MakeBitfield(DesiredAddr, AtomicLVal.getBitFieldInfo(), 1880 AtomicLVal.getType(), AtomicLVal.getBaseInfo(), 1881 AtomicLVal.getTBAAInfo()); 1882 } else if (AtomicLVal.isVectorElt()) { 1883 DesiredLVal = 1884 LValue::MakeVectorElt(DesiredAddr, AtomicLVal.getVectorIdx(), 1885 AtomicLVal.getType(), AtomicLVal.getBaseInfo(), 1886 AtomicLVal.getTBAAInfo()); 1887 } else { 1888 assert(AtomicLVal.isExtVectorElt()); 1889 DesiredLVal = LValue::MakeExtVectorElt( 1890 DesiredAddr, AtomicLVal.getExtVectorElts(), AtomicLVal.getType(), 1891 AtomicLVal.getBaseInfo(), AtomicLVal.getTBAAInfo()); 1892 } 1893 // Store new value in the corresponding memory area. 1894 assert(UpdateRVal.isScalar()); 1895 CGF.EmitStoreThroughLValue(UpdateRVal, DesiredLVal); 1896 } 1897 1898 void AtomicInfo::EmitAtomicUpdateLibcall(llvm::AtomicOrdering AO, 1899 RValue UpdateRVal, bool IsVolatile) { 1900 auto Failure = llvm::AtomicCmpXchgInst::getStrongestFailureOrdering(AO); 1901 1902 Address ExpectedAddr = CreateTempAlloca(); 1903 1904 EmitAtomicLoadLibcall(ExpectedAddr.getPointer(), AO, IsVolatile); 1905 auto *ContBB = CGF.createBasicBlock("atomic_cont"); 1906 auto *ExitBB = CGF.createBasicBlock("atomic_exit"); 1907 CGF.EmitBlock(ContBB); 1908 Address DesiredAddr = CreateTempAlloca(); 1909 if ((LVal.isBitField() && BFI.Size != ValueSizeInBits) || 1910 requiresMemSetZero(getAtomicAddress().getElementType())) { 1911 auto *OldVal = CGF.Builder.CreateLoad(ExpectedAddr); 1912 CGF.Builder.CreateStore(OldVal, DesiredAddr); 1913 } 1914 EmitAtomicUpdateValue(CGF, *this, UpdateRVal, DesiredAddr); 1915 auto *Res = 1916 EmitAtomicCompareExchangeLibcall(ExpectedAddr.getPointer(), 1917 DesiredAddr.getPointer(), 1918 AO, Failure); 1919 CGF.Builder.CreateCondBr(Res, ExitBB, ContBB); 1920 CGF.EmitBlock(ExitBB, /*IsFinished=*/true); 1921 } 1922 1923 void AtomicInfo::EmitAtomicUpdateOp(llvm::AtomicOrdering AO, RValue UpdateRVal, 1924 bool IsVolatile) { 1925 auto Failure = llvm::AtomicCmpXchgInst::getStrongestFailureOrdering(AO); 1926 1927 // Do the atomic load. 1928 auto *OldVal = EmitAtomicLoadOp(Failure, IsVolatile); 1929 // For non-simple lvalues perform compare-and-swap procedure. 1930 auto *ContBB = CGF.createBasicBlock("atomic_cont"); 1931 auto *ExitBB = CGF.createBasicBlock("atomic_exit"); 1932 auto *CurBB = CGF.Builder.GetInsertBlock(); 1933 CGF.EmitBlock(ContBB); 1934 llvm::PHINode *PHI = CGF.Builder.CreatePHI(OldVal->getType(), 1935 /*NumReservedValues=*/2); 1936 PHI->addIncoming(OldVal, CurBB); 1937 Address NewAtomicAddr = CreateTempAlloca(); 1938 Address NewAtomicIntAddr = emitCastToAtomicIntPointer(NewAtomicAddr); 1939 if ((LVal.isBitField() && BFI.Size != ValueSizeInBits) || 1940 requiresMemSetZero(getAtomicAddress().getElementType())) { 1941 CGF.Builder.CreateStore(PHI, NewAtomicIntAddr); 1942 } 1943 EmitAtomicUpdateValue(CGF, *this, UpdateRVal, NewAtomicAddr); 1944 auto *DesiredVal = CGF.Builder.CreateLoad(NewAtomicIntAddr); 1945 // Try to write new value using cmpxchg operation. 1946 auto Res = EmitAtomicCompareExchangeOp(PHI, DesiredVal, AO, Failure); 1947 PHI->addIncoming(Res.first, CGF.Builder.GetInsertBlock()); 1948 CGF.Builder.CreateCondBr(Res.second, ExitBB, ContBB); 1949 CGF.EmitBlock(ExitBB, /*IsFinished=*/true); 1950 } 1951 1952 void AtomicInfo::EmitAtomicUpdate( 1953 llvm::AtomicOrdering AO, const llvm::function_ref<RValue(RValue)> &UpdateOp, 1954 bool IsVolatile) { 1955 if (shouldUseLibcall()) { 1956 EmitAtomicUpdateLibcall(AO, UpdateOp, IsVolatile); 1957 } else { 1958 EmitAtomicUpdateOp(AO, UpdateOp, IsVolatile); 1959 } 1960 } 1961 1962 void AtomicInfo::EmitAtomicUpdate(llvm::AtomicOrdering AO, RValue UpdateRVal, 1963 bool IsVolatile) { 1964 if (shouldUseLibcall()) { 1965 EmitAtomicUpdateLibcall(AO, UpdateRVal, IsVolatile); 1966 } else { 1967 EmitAtomicUpdateOp(AO, UpdateRVal, IsVolatile); 1968 } 1969 } 1970 1971 void CodeGenFunction::EmitAtomicStore(RValue rvalue, LValue lvalue, 1972 bool isInit) { 1973 bool IsVolatile = lvalue.isVolatileQualified(); 1974 llvm::AtomicOrdering AO; 1975 if (lvalue.getType()->isAtomicType()) { 1976 AO = llvm::AtomicOrdering::SequentiallyConsistent; 1977 } else { 1978 AO = llvm::AtomicOrdering::Release; 1979 IsVolatile = true; 1980 } 1981 return EmitAtomicStore(rvalue, lvalue, AO, IsVolatile, isInit); 1982 } 1983 1984 /// Emit a store to an l-value of atomic type. 1985 /// 1986 /// Note that the r-value is expected to be an r-value *of the atomic 1987 /// type*; this means that for aggregate r-values, it should include 1988 /// storage for any padding that was necessary. 1989 void CodeGenFunction::EmitAtomicStore(RValue rvalue, LValue dest, 1990 llvm::AtomicOrdering AO, bool IsVolatile, 1991 bool isInit) { 1992 // If this is an aggregate r-value, it should agree in type except 1993 // maybe for address-space qualification. 1994 assert(!rvalue.isAggregate() || 1995 rvalue.getAggregateAddress().getElementType() == 1996 dest.getAddress(*this).getElementType()); 1997 1998 AtomicInfo atomics(*this, dest); 1999 LValue LVal = atomics.getAtomicLValue(); 2000 2001 // If this is an initialization, just put the value there normally. 2002 if (LVal.isSimple()) { 2003 if (isInit) { 2004 atomics.emitCopyIntoMemory(rvalue); 2005 return; 2006 } 2007 2008 // Check whether we should use a library call. 2009 if (atomics.shouldUseLibcall()) { 2010 // Produce a source address. 2011 Address srcAddr = atomics.materializeRValue(rvalue); 2012 2013 // void __atomic_store(size_t size, void *mem, void *val, int order) 2014 CallArgList args; 2015 args.add(RValue::get(atomics.getAtomicSizeValue()), 2016 getContext().getSizeType()); 2017 args.add(RValue::get(EmitCastToVoidPtr(atomics.getAtomicPointer())), 2018 getContext().VoidPtrTy); 2019 args.add(RValue::get(EmitCastToVoidPtr(srcAddr.getPointer())), 2020 getContext().VoidPtrTy); 2021 args.add( 2022 RValue::get(llvm::ConstantInt::get(IntTy, (int)llvm::toCABI(AO))), 2023 getContext().IntTy); 2024 emitAtomicLibcall(*this, "__atomic_store", getContext().VoidTy, args); 2025 return; 2026 } 2027 2028 // Okay, we're doing this natively. 2029 llvm::Value *intValue = atomics.convertRValueToInt(rvalue); 2030 2031 // Do the atomic store. 2032 Address addr = 2033 atomics.emitCastToAtomicIntPointer(atomics.getAtomicAddress()); 2034 intValue = Builder.CreateIntCast( 2035 intValue, addr.getElementType(), /*isSigned=*/false); 2036 llvm::StoreInst *store = Builder.CreateStore(intValue, addr); 2037 2038 if (AO == llvm::AtomicOrdering::Acquire) 2039 AO = llvm::AtomicOrdering::Monotonic; 2040 else if (AO == llvm::AtomicOrdering::AcquireRelease) 2041 AO = llvm::AtomicOrdering::Release; 2042 // Initializations don't need to be atomic. 2043 if (!isInit) 2044 store->setAtomic(AO); 2045 2046 // Other decoration. 2047 if (IsVolatile) 2048 store->setVolatile(true); 2049 CGM.DecorateInstructionWithTBAA(store, dest.getTBAAInfo()); 2050 return; 2051 } 2052 2053 // Emit simple atomic update operation. 2054 atomics.EmitAtomicUpdate(AO, rvalue, IsVolatile); 2055 } 2056 2057 /// Emit a compare-and-exchange op for atomic type. 2058 /// 2059 std::pair<RValue, llvm::Value *> CodeGenFunction::EmitAtomicCompareExchange( 2060 LValue Obj, RValue Expected, RValue Desired, SourceLocation Loc, 2061 llvm::AtomicOrdering Success, llvm::AtomicOrdering Failure, bool IsWeak, 2062 AggValueSlot Slot) { 2063 // If this is an aggregate r-value, it should agree in type except 2064 // maybe for address-space qualification. 2065 assert(!Expected.isAggregate() || 2066 Expected.getAggregateAddress().getElementType() == 2067 Obj.getAddress(*this).getElementType()); 2068 assert(!Desired.isAggregate() || 2069 Desired.getAggregateAddress().getElementType() == 2070 Obj.getAddress(*this).getElementType()); 2071 AtomicInfo Atomics(*this, Obj); 2072 2073 return Atomics.EmitAtomicCompareExchange(Expected, Desired, Success, Failure, 2074 IsWeak); 2075 } 2076 2077 void CodeGenFunction::EmitAtomicUpdate( 2078 LValue LVal, llvm::AtomicOrdering AO, 2079 const llvm::function_ref<RValue(RValue)> &UpdateOp, bool IsVolatile) { 2080 AtomicInfo Atomics(*this, LVal); 2081 Atomics.EmitAtomicUpdate(AO, UpdateOp, IsVolatile); 2082 } 2083 2084 void CodeGenFunction::EmitAtomicInit(Expr *init, LValue dest) { 2085 AtomicInfo atomics(*this, dest); 2086 2087 switch (atomics.getEvaluationKind()) { 2088 case TEK_Scalar: { 2089 llvm::Value *value = EmitScalarExpr(init); 2090 atomics.emitCopyIntoMemory(RValue::get(value)); 2091 return; 2092 } 2093 2094 case TEK_Complex: { 2095 ComplexPairTy value = EmitComplexExpr(init); 2096 atomics.emitCopyIntoMemory(RValue::getComplex(value)); 2097 return; 2098 } 2099 2100 case TEK_Aggregate: { 2101 // Fix up the destination if the initializer isn't an expression 2102 // of atomic type. 2103 bool Zeroed = false; 2104 if (!init->getType()->isAtomicType()) { 2105 Zeroed = atomics.emitMemSetZeroIfNecessary(); 2106 dest = atomics.projectValue(); 2107 } 2108 2109 // Evaluate the expression directly into the destination. 2110 AggValueSlot slot = AggValueSlot::forLValue( 2111 dest, *this, AggValueSlot::IsNotDestructed, 2112 AggValueSlot::DoesNotNeedGCBarriers, AggValueSlot::IsNotAliased, 2113 AggValueSlot::DoesNotOverlap, 2114 Zeroed ? AggValueSlot::IsZeroed : AggValueSlot::IsNotZeroed); 2115 2116 EmitAggExpr(init, slot); 2117 return; 2118 } 2119 } 2120 llvm_unreachable("bad evaluation kind"); 2121 } 2122