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 CGF.Int8Ty, 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 // 31.7.2.18: "The failure argument shall not be memory_order_release 431 // nor memory_order_acq_rel". Fallback to monotonic. 432 case llvm::AtomicOrderingCABI::release: 433 case llvm::AtomicOrderingCABI::acq_rel: 434 FailureOrder = llvm::AtomicOrdering::Monotonic; 435 break; 436 case llvm::AtomicOrderingCABI::consume: 437 case llvm::AtomicOrderingCABI::acquire: 438 FailureOrder = llvm::AtomicOrdering::Acquire; 439 break; 440 case llvm::AtomicOrderingCABI::seq_cst: 441 FailureOrder = llvm::AtomicOrdering::SequentiallyConsistent; 442 break; 443 } 444 // Prior to c++17, "the failure argument shall be no stronger than the 445 // success argument". This condition has been lifted and the only 446 // precondition is 31.7.2.18. Effectively treat this as a DR and skip 447 // language version checks. 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 auto *MonotonicBB = CGF.createBasicBlock("monotonic_fail", CGF.CurFn); 455 auto *AcquireBB = CGF.createBasicBlock("acquire_fail", CGF.CurFn); 456 auto *SeqCstBB = CGF.createBasicBlock("seqcst_fail", CGF.CurFn); 457 auto *ContBB = CGF.createBasicBlock("atomic.continue", CGF.CurFn); 458 459 // MonotonicBB is arbitrarily chosen as the default case; in practice, this 460 // doesn't matter unless someone is crazy enough to use something that 461 // doesn't fold to a constant for the ordering. 462 llvm::SwitchInst *SI = CGF.Builder.CreateSwitch(FailureOrderVal, MonotonicBB); 463 // Implemented as acquire, since it's the closest in LLVM. 464 SI->addCase(CGF.Builder.getInt32((int)llvm::AtomicOrderingCABI::consume), 465 AcquireBB); 466 SI->addCase(CGF.Builder.getInt32((int)llvm::AtomicOrderingCABI::acquire), 467 AcquireBB); 468 SI->addCase(CGF.Builder.getInt32((int)llvm::AtomicOrderingCABI::seq_cst), 469 SeqCstBB); 470 471 // Emit all the different atomics 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 CGF.Builder.SetInsertPoint(AcquireBB); 478 emitAtomicCmpXchg(CGF, E, IsWeak, Dest, Ptr, Val1, Val2, Size, SuccessOrder, 479 llvm::AtomicOrdering::Acquire, Scope); 480 CGF.Builder.CreateBr(ContBB); 481 482 CGF.Builder.SetInsertPoint(SeqCstBB); 483 emitAtomicCmpXchg(CGF, E, IsWeak, Dest, Ptr, Val1, Val2, Size, SuccessOrder, 484 llvm::AtomicOrdering::SequentiallyConsistent, Scope); 485 CGF.Builder.CreateBr(ContBB); 486 487 CGF.Builder.SetInsertPoint(ContBB); 488 } 489 490 /// Duplicate the atomic min/max operation in conventional IR for the builtin 491 /// variants that return the new rather than the original value. 492 static llvm::Value *EmitPostAtomicMinMax(CGBuilderTy &Builder, 493 AtomicExpr::AtomicOp Op, 494 bool IsSigned, 495 llvm::Value *OldVal, 496 llvm::Value *RHS) { 497 llvm::CmpInst::Predicate Pred; 498 switch (Op) { 499 default: 500 llvm_unreachable("Unexpected min/max operation"); 501 case AtomicExpr::AO__atomic_max_fetch: 502 Pred = IsSigned ? llvm::CmpInst::ICMP_SGT : llvm::CmpInst::ICMP_UGT; 503 break; 504 case AtomicExpr::AO__atomic_min_fetch: 505 Pred = IsSigned ? llvm::CmpInst::ICMP_SLT : llvm::CmpInst::ICMP_ULT; 506 break; 507 } 508 llvm::Value *Cmp = Builder.CreateICmp(Pred, OldVal, RHS, "tst"); 509 return Builder.CreateSelect(Cmp, OldVal, RHS, "newval"); 510 } 511 512 static void EmitAtomicOp(CodeGenFunction &CGF, AtomicExpr *E, Address Dest, 513 Address Ptr, Address Val1, Address Val2, 514 llvm::Value *IsWeak, llvm::Value *FailureOrder, 515 uint64_t Size, llvm::AtomicOrdering Order, 516 llvm::SyncScope::ID Scope) { 517 llvm::AtomicRMWInst::BinOp Op = llvm::AtomicRMWInst::Add; 518 bool PostOpMinMax = false; 519 unsigned PostOp = 0; 520 521 switch (E->getOp()) { 522 case AtomicExpr::AO__c11_atomic_init: 523 case AtomicExpr::AO__opencl_atomic_init: 524 llvm_unreachable("Already handled!"); 525 526 case AtomicExpr::AO__c11_atomic_compare_exchange_strong: 527 case AtomicExpr::AO__opencl_atomic_compare_exchange_strong: 528 emitAtomicCmpXchgFailureSet(CGF, E, false, Dest, Ptr, Val1, Val2, 529 FailureOrder, Size, Order, Scope); 530 return; 531 case AtomicExpr::AO__c11_atomic_compare_exchange_weak: 532 case AtomicExpr::AO__opencl_atomic_compare_exchange_weak: 533 emitAtomicCmpXchgFailureSet(CGF, E, true, Dest, Ptr, Val1, Val2, 534 FailureOrder, Size, Order, Scope); 535 return; 536 case AtomicExpr::AO__atomic_compare_exchange: 537 case AtomicExpr::AO__atomic_compare_exchange_n: { 538 if (llvm::ConstantInt *IsWeakC = dyn_cast<llvm::ConstantInt>(IsWeak)) { 539 emitAtomicCmpXchgFailureSet(CGF, E, IsWeakC->getZExtValue(), Dest, Ptr, 540 Val1, Val2, FailureOrder, Size, Order, Scope); 541 } else { 542 // Create all the relevant BB's 543 llvm::BasicBlock *StrongBB = 544 CGF.createBasicBlock("cmpxchg.strong", CGF.CurFn); 545 llvm::BasicBlock *WeakBB = CGF.createBasicBlock("cmxchg.weak", CGF.CurFn); 546 llvm::BasicBlock *ContBB = 547 CGF.createBasicBlock("cmpxchg.continue", CGF.CurFn); 548 549 llvm::SwitchInst *SI = CGF.Builder.CreateSwitch(IsWeak, WeakBB); 550 SI->addCase(CGF.Builder.getInt1(false), StrongBB); 551 552 CGF.Builder.SetInsertPoint(StrongBB); 553 emitAtomicCmpXchgFailureSet(CGF, E, false, Dest, Ptr, Val1, Val2, 554 FailureOrder, Size, Order, Scope); 555 CGF.Builder.CreateBr(ContBB); 556 557 CGF.Builder.SetInsertPoint(WeakBB); 558 emitAtomicCmpXchgFailureSet(CGF, E, true, Dest, Ptr, Val1, Val2, 559 FailureOrder, Size, Order, Scope); 560 CGF.Builder.CreateBr(ContBB); 561 562 CGF.Builder.SetInsertPoint(ContBB); 563 } 564 return; 565 } 566 case AtomicExpr::AO__c11_atomic_load: 567 case AtomicExpr::AO__opencl_atomic_load: 568 case AtomicExpr::AO__atomic_load_n: 569 case AtomicExpr::AO__atomic_load: { 570 llvm::LoadInst *Load = CGF.Builder.CreateLoad(Ptr); 571 Load->setAtomic(Order, Scope); 572 Load->setVolatile(E->isVolatile()); 573 CGF.Builder.CreateStore(Load, Dest); 574 return; 575 } 576 577 case AtomicExpr::AO__c11_atomic_store: 578 case AtomicExpr::AO__opencl_atomic_store: 579 case AtomicExpr::AO__atomic_store: 580 case AtomicExpr::AO__atomic_store_n: { 581 llvm::Value *LoadVal1 = CGF.Builder.CreateLoad(Val1); 582 llvm::StoreInst *Store = CGF.Builder.CreateStore(LoadVal1, Ptr); 583 Store->setAtomic(Order, Scope); 584 Store->setVolatile(E->isVolatile()); 585 return; 586 } 587 588 case AtomicExpr::AO__c11_atomic_exchange: 589 case AtomicExpr::AO__opencl_atomic_exchange: 590 case AtomicExpr::AO__atomic_exchange_n: 591 case AtomicExpr::AO__atomic_exchange: 592 Op = llvm::AtomicRMWInst::Xchg; 593 break; 594 595 case AtomicExpr::AO__atomic_add_fetch: 596 PostOp = E->getValueType()->isFloatingType() ? llvm::Instruction::FAdd 597 : llvm::Instruction::Add; 598 LLVM_FALLTHROUGH; 599 case AtomicExpr::AO__c11_atomic_fetch_add: 600 case AtomicExpr::AO__opencl_atomic_fetch_add: 601 case AtomicExpr::AO__atomic_fetch_add: 602 Op = E->getValueType()->isFloatingType() ? llvm::AtomicRMWInst::FAdd 603 : llvm::AtomicRMWInst::Add; 604 break; 605 606 case AtomicExpr::AO__atomic_sub_fetch: 607 PostOp = E->getValueType()->isFloatingType() ? llvm::Instruction::FSub 608 : llvm::Instruction::Sub; 609 LLVM_FALLTHROUGH; 610 case AtomicExpr::AO__c11_atomic_fetch_sub: 611 case AtomicExpr::AO__opencl_atomic_fetch_sub: 612 case AtomicExpr::AO__atomic_fetch_sub: 613 Op = E->getValueType()->isFloatingType() ? llvm::AtomicRMWInst::FSub 614 : llvm::AtomicRMWInst::Sub; 615 break; 616 617 case AtomicExpr::AO__atomic_min_fetch: 618 PostOpMinMax = true; 619 LLVM_FALLTHROUGH; 620 case AtomicExpr::AO__c11_atomic_fetch_min: 621 case AtomicExpr::AO__opencl_atomic_fetch_min: 622 case AtomicExpr::AO__atomic_fetch_min: 623 Op = E->getValueType()->isSignedIntegerType() ? llvm::AtomicRMWInst::Min 624 : llvm::AtomicRMWInst::UMin; 625 break; 626 627 case AtomicExpr::AO__atomic_max_fetch: 628 PostOpMinMax = true; 629 LLVM_FALLTHROUGH; 630 case AtomicExpr::AO__c11_atomic_fetch_max: 631 case AtomicExpr::AO__opencl_atomic_fetch_max: 632 case AtomicExpr::AO__atomic_fetch_max: 633 Op = E->getValueType()->isSignedIntegerType() ? llvm::AtomicRMWInst::Max 634 : llvm::AtomicRMWInst::UMax; 635 break; 636 637 case AtomicExpr::AO__atomic_and_fetch: 638 PostOp = llvm::Instruction::And; 639 LLVM_FALLTHROUGH; 640 case AtomicExpr::AO__c11_atomic_fetch_and: 641 case AtomicExpr::AO__opencl_atomic_fetch_and: 642 case AtomicExpr::AO__atomic_fetch_and: 643 Op = llvm::AtomicRMWInst::And; 644 break; 645 646 case AtomicExpr::AO__atomic_or_fetch: 647 PostOp = llvm::Instruction::Or; 648 LLVM_FALLTHROUGH; 649 case AtomicExpr::AO__c11_atomic_fetch_or: 650 case AtomicExpr::AO__opencl_atomic_fetch_or: 651 case AtomicExpr::AO__atomic_fetch_or: 652 Op = llvm::AtomicRMWInst::Or; 653 break; 654 655 case AtomicExpr::AO__atomic_xor_fetch: 656 PostOp = llvm::Instruction::Xor; 657 LLVM_FALLTHROUGH; 658 case AtomicExpr::AO__c11_atomic_fetch_xor: 659 case AtomicExpr::AO__opencl_atomic_fetch_xor: 660 case AtomicExpr::AO__atomic_fetch_xor: 661 Op = llvm::AtomicRMWInst::Xor; 662 break; 663 664 case AtomicExpr::AO__atomic_nand_fetch: 665 PostOp = llvm::Instruction::And; // the NOT is special cased below 666 LLVM_FALLTHROUGH; 667 case AtomicExpr::AO__c11_atomic_fetch_nand: 668 case AtomicExpr::AO__atomic_fetch_nand: 669 Op = llvm::AtomicRMWInst::Nand; 670 break; 671 } 672 673 llvm::Value *LoadVal1 = CGF.Builder.CreateLoad(Val1); 674 llvm::AtomicRMWInst *RMWI = 675 CGF.Builder.CreateAtomicRMW(Op, Ptr.getPointer(), LoadVal1, Order, Scope); 676 RMWI->setVolatile(E->isVolatile()); 677 678 // For __atomic_*_fetch operations, perform the operation again to 679 // determine the value which was written. 680 llvm::Value *Result = RMWI; 681 if (PostOpMinMax) 682 Result = EmitPostAtomicMinMax(CGF.Builder, E->getOp(), 683 E->getValueType()->isSignedIntegerType(), 684 RMWI, LoadVal1); 685 else if (PostOp) 686 Result = CGF.Builder.CreateBinOp((llvm::Instruction::BinaryOps)PostOp, RMWI, 687 LoadVal1); 688 if (E->getOp() == AtomicExpr::AO__atomic_nand_fetch) 689 Result = CGF.Builder.CreateNot(Result); 690 CGF.Builder.CreateStore(Result, Dest); 691 } 692 693 // This function emits any expression (scalar, complex, or aggregate) 694 // into a temporary alloca. 695 static Address 696 EmitValToTemp(CodeGenFunction &CGF, Expr *E) { 697 Address DeclPtr = CGF.CreateMemTemp(E->getType(), ".atomictmp"); 698 CGF.EmitAnyExprToMem(E, DeclPtr, E->getType().getQualifiers(), 699 /*Init*/ true); 700 return DeclPtr; 701 } 702 703 static void EmitAtomicOp(CodeGenFunction &CGF, AtomicExpr *Expr, Address Dest, 704 Address Ptr, Address Val1, Address Val2, 705 llvm::Value *IsWeak, llvm::Value *FailureOrder, 706 uint64_t Size, llvm::AtomicOrdering Order, 707 llvm::Value *Scope) { 708 auto ScopeModel = Expr->getScopeModel(); 709 710 // LLVM atomic instructions always have synch scope. If clang atomic 711 // expression has no scope operand, use default LLVM synch scope. 712 if (!ScopeModel) { 713 EmitAtomicOp(CGF, Expr, Dest, Ptr, Val1, Val2, IsWeak, FailureOrder, Size, 714 Order, CGF.CGM.getLLVMContext().getOrInsertSyncScopeID("")); 715 return; 716 } 717 718 // Handle constant scope. 719 if (auto SC = dyn_cast<llvm::ConstantInt>(Scope)) { 720 auto SCID = CGF.getTargetHooks().getLLVMSyncScopeID( 721 CGF.CGM.getLangOpts(), ScopeModel->map(SC->getZExtValue()), 722 Order, CGF.CGM.getLLVMContext()); 723 EmitAtomicOp(CGF, Expr, Dest, Ptr, Val1, Val2, IsWeak, FailureOrder, Size, 724 Order, SCID); 725 return; 726 } 727 728 // Handle non-constant scope. 729 auto &Builder = CGF.Builder; 730 auto Scopes = ScopeModel->getRuntimeValues(); 731 llvm::DenseMap<unsigned, llvm::BasicBlock *> BB; 732 for (auto S : Scopes) 733 BB[S] = CGF.createBasicBlock(getAsString(ScopeModel->map(S)), CGF.CurFn); 734 735 llvm::BasicBlock *ContBB = 736 CGF.createBasicBlock("atomic.scope.continue", CGF.CurFn); 737 738 auto *SC = Builder.CreateIntCast(Scope, Builder.getInt32Ty(), false); 739 // If unsupported synch scope is encountered at run time, assume a fallback 740 // synch scope value. 741 auto FallBack = ScopeModel->getFallBackValue(); 742 llvm::SwitchInst *SI = Builder.CreateSwitch(SC, BB[FallBack]); 743 for (auto S : Scopes) { 744 auto *B = BB[S]; 745 if (S != FallBack) 746 SI->addCase(Builder.getInt32(S), B); 747 748 Builder.SetInsertPoint(B); 749 EmitAtomicOp(CGF, Expr, Dest, Ptr, Val1, Val2, IsWeak, FailureOrder, Size, 750 Order, 751 CGF.getTargetHooks().getLLVMSyncScopeID(CGF.CGM.getLangOpts(), 752 ScopeModel->map(S), 753 Order, 754 CGF.getLLVMContext())); 755 Builder.CreateBr(ContBB); 756 } 757 758 Builder.SetInsertPoint(ContBB); 759 } 760 761 static void 762 AddDirectArgument(CodeGenFunction &CGF, CallArgList &Args, 763 bool UseOptimizedLibcall, llvm::Value *Val, QualType ValTy, 764 SourceLocation Loc, CharUnits SizeInChars) { 765 if (UseOptimizedLibcall) { 766 // Load value and pass it to the function directly. 767 CharUnits Align = CGF.getContext().getTypeAlignInChars(ValTy); 768 int64_t SizeInBits = CGF.getContext().toBits(SizeInChars); 769 ValTy = 770 CGF.getContext().getIntTypeForBitwidth(SizeInBits, /*Signed=*/false); 771 llvm::Type *IPtrTy = llvm::IntegerType::get(CGF.getLLVMContext(), 772 SizeInBits)->getPointerTo(); 773 Address Ptr = Address(CGF.Builder.CreateBitCast(Val, IPtrTy), Align); 774 Val = CGF.EmitLoadOfScalar(Ptr, false, 775 CGF.getContext().getPointerType(ValTy), 776 Loc); 777 // Coerce the value into an appropriately sized integer type. 778 Args.add(RValue::get(Val), ValTy); 779 } else { 780 // Non-optimized functions always take a reference. 781 Args.add(RValue::get(CGF.EmitCastToVoidPtr(Val)), 782 CGF.getContext().VoidPtrTy); 783 } 784 } 785 786 RValue CodeGenFunction::EmitAtomicExpr(AtomicExpr *E) { 787 QualType AtomicTy = E->getPtr()->getType()->getPointeeType(); 788 QualType MemTy = AtomicTy; 789 if (const AtomicType *AT = AtomicTy->getAs<AtomicType>()) 790 MemTy = AT->getValueType(); 791 llvm::Value *IsWeak = nullptr, *OrderFail = nullptr; 792 793 Address Val1 = Address::invalid(); 794 Address Val2 = Address::invalid(); 795 Address Dest = Address::invalid(); 796 Address Ptr = EmitPointerWithAlignment(E->getPtr()); 797 798 if (E->getOp() == AtomicExpr::AO__c11_atomic_init || 799 E->getOp() == AtomicExpr::AO__opencl_atomic_init) { 800 LValue lvalue = MakeAddrLValue(Ptr, AtomicTy); 801 EmitAtomicInit(E->getVal1(), lvalue); 802 return RValue::get(nullptr); 803 } 804 805 auto TInfo = getContext().getTypeInfoInChars(AtomicTy); 806 uint64_t Size = TInfo.Width.getQuantity(); 807 unsigned MaxInlineWidthInBits = getTarget().getMaxAtomicInlineWidth(); 808 809 bool Oversized = getContext().toBits(TInfo.Width) > MaxInlineWidthInBits; 810 bool Misaligned = (Ptr.getAlignment() % TInfo.Width) != 0; 811 bool UseLibcall = Misaligned | Oversized; 812 bool ShouldCastToIntPtrTy = true; 813 814 CharUnits MaxInlineWidth = 815 getContext().toCharUnitsFromBits(MaxInlineWidthInBits); 816 817 DiagnosticsEngine &Diags = CGM.getDiags(); 818 819 if (Misaligned) { 820 Diags.Report(E->getBeginLoc(), diag::warn_atomic_op_misaligned) 821 << (int)TInfo.Width.getQuantity() 822 << (int)Ptr.getAlignment().getQuantity(); 823 } 824 825 if (Oversized) { 826 Diags.Report(E->getBeginLoc(), diag::warn_atomic_op_oversized) 827 << (int)TInfo.Width.getQuantity() << (int)MaxInlineWidth.getQuantity(); 828 } 829 830 llvm::Value *Order = EmitScalarExpr(E->getOrder()); 831 llvm::Value *Scope = 832 E->getScopeModel() ? EmitScalarExpr(E->getScope()) : nullptr; 833 834 switch (E->getOp()) { 835 case AtomicExpr::AO__c11_atomic_init: 836 case AtomicExpr::AO__opencl_atomic_init: 837 llvm_unreachable("Already handled above with EmitAtomicInit!"); 838 839 case AtomicExpr::AO__c11_atomic_load: 840 case AtomicExpr::AO__opencl_atomic_load: 841 case AtomicExpr::AO__atomic_load_n: 842 break; 843 844 case AtomicExpr::AO__atomic_load: 845 Dest = EmitPointerWithAlignment(E->getVal1()); 846 break; 847 848 case AtomicExpr::AO__atomic_store: 849 Val1 = EmitPointerWithAlignment(E->getVal1()); 850 break; 851 852 case AtomicExpr::AO__atomic_exchange: 853 Val1 = EmitPointerWithAlignment(E->getVal1()); 854 Dest = EmitPointerWithAlignment(E->getVal2()); 855 break; 856 857 case AtomicExpr::AO__c11_atomic_compare_exchange_strong: 858 case AtomicExpr::AO__c11_atomic_compare_exchange_weak: 859 case AtomicExpr::AO__opencl_atomic_compare_exchange_strong: 860 case AtomicExpr::AO__opencl_atomic_compare_exchange_weak: 861 case AtomicExpr::AO__atomic_compare_exchange_n: 862 case AtomicExpr::AO__atomic_compare_exchange: 863 Val1 = EmitPointerWithAlignment(E->getVal1()); 864 if (E->getOp() == AtomicExpr::AO__atomic_compare_exchange) 865 Val2 = EmitPointerWithAlignment(E->getVal2()); 866 else 867 Val2 = EmitValToTemp(*this, E->getVal2()); 868 OrderFail = EmitScalarExpr(E->getOrderFail()); 869 if (E->getOp() == AtomicExpr::AO__atomic_compare_exchange_n || 870 E->getOp() == AtomicExpr::AO__atomic_compare_exchange) 871 IsWeak = EmitScalarExpr(E->getWeak()); 872 break; 873 874 case AtomicExpr::AO__c11_atomic_fetch_add: 875 case AtomicExpr::AO__c11_atomic_fetch_sub: 876 case AtomicExpr::AO__opencl_atomic_fetch_add: 877 case AtomicExpr::AO__opencl_atomic_fetch_sub: 878 if (MemTy->isPointerType()) { 879 // For pointer arithmetic, we're required to do a bit of math: 880 // adding 1 to an int* is not the same as adding 1 to a uintptr_t. 881 // ... but only for the C11 builtins. The GNU builtins expect the 882 // user to multiply by sizeof(T). 883 QualType Val1Ty = E->getVal1()->getType(); 884 llvm::Value *Val1Scalar = EmitScalarExpr(E->getVal1()); 885 CharUnits PointeeIncAmt = 886 getContext().getTypeSizeInChars(MemTy->getPointeeType()); 887 Val1Scalar = Builder.CreateMul(Val1Scalar, CGM.getSize(PointeeIncAmt)); 888 auto Temp = CreateMemTemp(Val1Ty, ".atomictmp"); 889 Val1 = Temp; 890 EmitStoreOfScalar(Val1Scalar, MakeAddrLValue(Temp, Val1Ty)); 891 break; 892 } 893 LLVM_FALLTHROUGH; 894 case AtomicExpr::AO__atomic_fetch_add: 895 case AtomicExpr::AO__atomic_fetch_sub: 896 case AtomicExpr::AO__atomic_add_fetch: 897 case AtomicExpr::AO__atomic_sub_fetch: 898 ShouldCastToIntPtrTy = !MemTy->isFloatingType(); 899 LLVM_FALLTHROUGH; 900 901 case AtomicExpr::AO__c11_atomic_store: 902 case AtomicExpr::AO__c11_atomic_exchange: 903 case AtomicExpr::AO__opencl_atomic_store: 904 case AtomicExpr::AO__opencl_atomic_exchange: 905 case AtomicExpr::AO__atomic_store_n: 906 case AtomicExpr::AO__atomic_exchange_n: 907 case AtomicExpr::AO__c11_atomic_fetch_and: 908 case AtomicExpr::AO__c11_atomic_fetch_or: 909 case AtomicExpr::AO__c11_atomic_fetch_xor: 910 case AtomicExpr::AO__c11_atomic_fetch_nand: 911 case AtomicExpr::AO__c11_atomic_fetch_max: 912 case AtomicExpr::AO__c11_atomic_fetch_min: 913 case AtomicExpr::AO__opencl_atomic_fetch_and: 914 case AtomicExpr::AO__opencl_atomic_fetch_or: 915 case AtomicExpr::AO__opencl_atomic_fetch_xor: 916 case AtomicExpr::AO__opencl_atomic_fetch_min: 917 case AtomicExpr::AO__opencl_atomic_fetch_max: 918 case AtomicExpr::AO__atomic_fetch_and: 919 case AtomicExpr::AO__atomic_fetch_or: 920 case AtomicExpr::AO__atomic_fetch_xor: 921 case AtomicExpr::AO__atomic_fetch_nand: 922 case AtomicExpr::AO__atomic_and_fetch: 923 case AtomicExpr::AO__atomic_or_fetch: 924 case AtomicExpr::AO__atomic_xor_fetch: 925 case AtomicExpr::AO__atomic_nand_fetch: 926 case AtomicExpr::AO__atomic_max_fetch: 927 case AtomicExpr::AO__atomic_min_fetch: 928 case AtomicExpr::AO__atomic_fetch_max: 929 case AtomicExpr::AO__atomic_fetch_min: 930 Val1 = EmitValToTemp(*this, E->getVal1()); 931 break; 932 } 933 934 QualType RValTy = E->getType().getUnqualifiedType(); 935 936 // The inlined atomics only function on iN types, where N is a power of 2. We 937 // need to make sure (via temporaries if necessary) that all incoming values 938 // are compatible. 939 LValue AtomicVal = MakeAddrLValue(Ptr, AtomicTy); 940 AtomicInfo Atomics(*this, AtomicVal); 941 942 if (ShouldCastToIntPtrTy) { 943 Ptr = Atomics.emitCastToAtomicIntPointer(Ptr); 944 if (Val1.isValid()) 945 Val1 = Atomics.convertToAtomicIntPointer(Val1); 946 if (Val2.isValid()) 947 Val2 = Atomics.convertToAtomicIntPointer(Val2); 948 } 949 if (Dest.isValid()) { 950 if (ShouldCastToIntPtrTy) 951 Dest = Atomics.emitCastToAtomicIntPointer(Dest); 952 } else if (E->isCmpXChg()) 953 Dest = CreateMemTemp(RValTy, "cmpxchg.bool"); 954 else if (!RValTy->isVoidType()) { 955 Dest = Atomics.CreateTempAlloca(); 956 if (ShouldCastToIntPtrTy) 957 Dest = Atomics.emitCastToAtomicIntPointer(Dest); 958 } 959 960 // Use a library call. See: http://gcc.gnu.org/wiki/Atomic/GCCMM/LIbrary . 961 if (UseLibcall) { 962 bool UseOptimizedLibcall = false; 963 switch (E->getOp()) { 964 case AtomicExpr::AO__c11_atomic_init: 965 case AtomicExpr::AO__opencl_atomic_init: 966 llvm_unreachable("Already handled above with EmitAtomicInit!"); 967 968 case AtomicExpr::AO__c11_atomic_fetch_add: 969 case AtomicExpr::AO__opencl_atomic_fetch_add: 970 case AtomicExpr::AO__atomic_fetch_add: 971 case AtomicExpr::AO__c11_atomic_fetch_and: 972 case AtomicExpr::AO__opencl_atomic_fetch_and: 973 case AtomicExpr::AO__atomic_fetch_and: 974 case AtomicExpr::AO__c11_atomic_fetch_or: 975 case AtomicExpr::AO__opencl_atomic_fetch_or: 976 case AtomicExpr::AO__atomic_fetch_or: 977 case AtomicExpr::AO__c11_atomic_fetch_nand: 978 case AtomicExpr::AO__atomic_fetch_nand: 979 case AtomicExpr::AO__c11_atomic_fetch_sub: 980 case AtomicExpr::AO__opencl_atomic_fetch_sub: 981 case AtomicExpr::AO__atomic_fetch_sub: 982 case AtomicExpr::AO__c11_atomic_fetch_xor: 983 case AtomicExpr::AO__opencl_atomic_fetch_xor: 984 case AtomicExpr::AO__opencl_atomic_fetch_min: 985 case AtomicExpr::AO__opencl_atomic_fetch_max: 986 case AtomicExpr::AO__atomic_fetch_xor: 987 case AtomicExpr::AO__c11_atomic_fetch_max: 988 case AtomicExpr::AO__c11_atomic_fetch_min: 989 case AtomicExpr::AO__atomic_add_fetch: 990 case AtomicExpr::AO__atomic_and_fetch: 991 case AtomicExpr::AO__atomic_nand_fetch: 992 case AtomicExpr::AO__atomic_or_fetch: 993 case AtomicExpr::AO__atomic_sub_fetch: 994 case AtomicExpr::AO__atomic_xor_fetch: 995 case AtomicExpr::AO__atomic_fetch_max: 996 case AtomicExpr::AO__atomic_fetch_min: 997 case AtomicExpr::AO__atomic_max_fetch: 998 case AtomicExpr::AO__atomic_min_fetch: 999 // For these, only library calls for certain sizes exist. 1000 UseOptimizedLibcall = true; 1001 break; 1002 1003 case AtomicExpr::AO__atomic_load: 1004 case AtomicExpr::AO__atomic_store: 1005 case AtomicExpr::AO__atomic_exchange: 1006 case AtomicExpr::AO__atomic_compare_exchange: 1007 // Use the generic version if we don't know that the operand will be 1008 // suitably aligned for the optimized version. 1009 if (Misaligned) 1010 break; 1011 LLVM_FALLTHROUGH; 1012 case AtomicExpr::AO__c11_atomic_load: 1013 case AtomicExpr::AO__c11_atomic_store: 1014 case AtomicExpr::AO__c11_atomic_exchange: 1015 case AtomicExpr::AO__c11_atomic_compare_exchange_weak: 1016 case AtomicExpr::AO__c11_atomic_compare_exchange_strong: 1017 case AtomicExpr::AO__opencl_atomic_load: 1018 case AtomicExpr::AO__opencl_atomic_store: 1019 case AtomicExpr::AO__opencl_atomic_exchange: 1020 case AtomicExpr::AO__opencl_atomic_compare_exchange_weak: 1021 case AtomicExpr::AO__opencl_atomic_compare_exchange_strong: 1022 case AtomicExpr::AO__atomic_load_n: 1023 case AtomicExpr::AO__atomic_store_n: 1024 case AtomicExpr::AO__atomic_exchange_n: 1025 case AtomicExpr::AO__atomic_compare_exchange_n: 1026 // Only use optimized library calls for sizes for which they exist. 1027 // FIXME: Size == 16 optimized library functions exist too. 1028 if (Size == 1 || Size == 2 || Size == 4 || Size == 8) 1029 UseOptimizedLibcall = true; 1030 break; 1031 } 1032 1033 CallArgList Args; 1034 if (!UseOptimizedLibcall) { 1035 // For non-optimized library calls, the size is the first parameter 1036 Args.add(RValue::get(llvm::ConstantInt::get(SizeTy, Size)), 1037 getContext().getSizeType()); 1038 } 1039 // Atomic address is the first or second parameter 1040 // The OpenCL atomic library functions only accept pointer arguments to 1041 // generic address space. 1042 auto CastToGenericAddrSpace = [&](llvm::Value *V, QualType PT) { 1043 if (!E->isOpenCL()) 1044 return V; 1045 auto AS = PT->castAs<PointerType>()->getPointeeType().getAddressSpace(); 1046 if (AS == LangAS::opencl_generic) 1047 return V; 1048 auto DestAS = getContext().getTargetAddressSpace(LangAS::opencl_generic); 1049 auto T = V->getType(); 1050 auto *DestType = T->getPointerElementType()->getPointerTo(DestAS); 1051 1052 return getTargetHooks().performAddrSpaceCast( 1053 *this, V, AS, LangAS::opencl_generic, DestType, false); 1054 }; 1055 1056 Args.add(RValue::get(CastToGenericAddrSpace( 1057 EmitCastToVoidPtr(Ptr.getPointer()), E->getPtr()->getType())), 1058 getContext().VoidPtrTy); 1059 1060 std::string LibCallName; 1061 QualType LoweredMemTy = 1062 MemTy->isPointerType() ? getContext().getIntPtrType() : MemTy; 1063 QualType RetTy; 1064 bool HaveRetTy = false; 1065 llvm::Instruction::BinaryOps PostOp = (llvm::Instruction::BinaryOps)0; 1066 bool PostOpMinMax = false; 1067 switch (E->getOp()) { 1068 case AtomicExpr::AO__c11_atomic_init: 1069 case AtomicExpr::AO__opencl_atomic_init: 1070 llvm_unreachable("Already handled!"); 1071 1072 // There is only one libcall for compare an exchange, because there is no 1073 // optimisation benefit possible from a libcall version of a weak compare 1074 // and exchange. 1075 // bool __atomic_compare_exchange(size_t size, void *mem, void *expected, 1076 // void *desired, int success, int failure) 1077 // bool __atomic_compare_exchange_N(T *mem, T *expected, T desired, 1078 // int success, int failure) 1079 case AtomicExpr::AO__c11_atomic_compare_exchange_weak: 1080 case AtomicExpr::AO__c11_atomic_compare_exchange_strong: 1081 case AtomicExpr::AO__opencl_atomic_compare_exchange_weak: 1082 case AtomicExpr::AO__opencl_atomic_compare_exchange_strong: 1083 case AtomicExpr::AO__atomic_compare_exchange: 1084 case AtomicExpr::AO__atomic_compare_exchange_n: 1085 LibCallName = "__atomic_compare_exchange"; 1086 RetTy = getContext().BoolTy; 1087 HaveRetTy = true; 1088 Args.add( 1089 RValue::get(CastToGenericAddrSpace( 1090 EmitCastToVoidPtr(Val1.getPointer()), E->getVal1()->getType())), 1091 getContext().VoidPtrTy); 1092 AddDirectArgument(*this, Args, UseOptimizedLibcall, Val2.getPointer(), 1093 MemTy, E->getExprLoc(), TInfo.Width); 1094 Args.add(RValue::get(Order), getContext().IntTy); 1095 Order = OrderFail; 1096 break; 1097 // void __atomic_exchange(size_t size, void *mem, void *val, void *return, 1098 // int order) 1099 // T __atomic_exchange_N(T *mem, T val, int order) 1100 case AtomicExpr::AO__c11_atomic_exchange: 1101 case AtomicExpr::AO__opencl_atomic_exchange: 1102 case AtomicExpr::AO__atomic_exchange_n: 1103 case AtomicExpr::AO__atomic_exchange: 1104 LibCallName = "__atomic_exchange"; 1105 AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(), 1106 MemTy, E->getExprLoc(), TInfo.Width); 1107 break; 1108 // void __atomic_store(size_t size, void *mem, void *val, int order) 1109 // void __atomic_store_N(T *mem, T val, int order) 1110 case AtomicExpr::AO__c11_atomic_store: 1111 case AtomicExpr::AO__opencl_atomic_store: 1112 case AtomicExpr::AO__atomic_store: 1113 case AtomicExpr::AO__atomic_store_n: 1114 LibCallName = "__atomic_store"; 1115 RetTy = getContext().VoidTy; 1116 HaveRetTy = true; 1117 AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(), 1118 MemTy, E->getExprLoc(), TInfo.Width); 1119 break; 1120 // void __atomic_load(size_t size, void *mem, void *return, int order) 1121 // T __atomic_load_N(T *mem, int order) 1122 case AtomicExpr::AO__c11_atomic_load: 1123 case AtomicExpr::AO__opencl_atomic_load: 1124 case AtomicExpr::AO__atomic_load: 1125 case AtomicExpr::AO__atomic_load_n: 1126 LibCallName = "__atomic_load"; 1127 break; 1128 // T __atomic_add_fetch_N(T *mem, T val, int order) 1129 // T __atomic_fetch_add_N(T *mem, T val, int order) 1130 case AtomicExpr::AO__atomic_add_fetch: 1131 PostOp = llvm::Instruction::Add; 1132 LLVM_FALLTHROUGH; 1133 case AtomicExpr::AO__c11_atomic_fetch_add: 1134 case AtomicExpr::AO__opencl_atomic_fetch_add: 1135 case AtomicExpr::AO__atomic_fetch_add: 1136 LibCallName = "__atomic_fetch_add"; 1137 AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(), 1138 LoweredMemTy, E->getExprLoc(), TInfo.Width); 1139 break; 1140 // T __atomic_and_fetch_N(T *mem, T val, int order) 1141 // T __atomic_fetch_and_N(T *mem, T val, int order) 1142 case AtomicExpr::AO__atomic_and_fetch: 1143 PostOp = llvm::Instruction::And; 1144 LLVM_FALLTHROUGH; 1145 case AtomicExpr::AO__c11_atomic_fetch_and: 1146 case AtomicExpr::AO__opencl_atomic_fetch_and: 1147 case AtomicExpr::AO__atomic_fetch_and: 1148 LibCallName = "__atomic_fetch_and"; 1149 AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(), 1150 MemTy, E->getExprLoc(), TInfo.Width); 1151 break; 1152 // T __atomic_or_fetch_N(T *mem, T val, int order) 1153 // T __atomic_fetch_or_N(T *mem, T val, int order) 1154 case AtomicExpr::AO__atomic_or_fetch: 1155 PostOp = llvm::Instruction::Or; 1156 LLVM_FALLTHROUGH; 1157 case AtomicExpr::AO__c11_atomic_fetch_or: 1158 case AtomicExpr::AO__opencl_atomic_fetch_or: 1159 case AtomicExpr::AO__atomic_fetch_or: 1160 LibCallName = "__atomic_fetch_or"; 1161 AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(), 1162 MemTy, E->getExprLoc(), TInfo.Width); 1163 break; 1164 // T __atomic_sub_fetch_N(T *mem, T val, int order) 1165 // T __atomic_fetch_sub_N(T *mem, T val, int order) 1166 case AtomicExpr::AO__atomic_sub_fetch: 1167 PostOp = llvm::Instruction::Sub; 1168 LLVM_FALLTHROUGH; 1169 case AtomicExpr::AO__c11_atomic_fetch_sub: 1170 case AtomicExpr::AO__opencl_atomic_fetch_sub: 1171 case AtomicExpr::AO__atomic_fetch_sub: 1172 LibCallName = "__atomic_fetch_sub"; 1173 AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(), 1174 LoweredMemTy, E->getExprLoc(), TInfo.Width); 1175 break; 1176 // T __atomic_xor_fetch_N(T *mem, T val, int order) 1177 // T __atomic_fetch_xor_N(T *mem, T val, int order) 1178 case AtomicExpr::AO__atomic_xor_fetch: 1179 PostOp = llvm::Instruction::Xor; 1180 LLVM_FALLTHROUGH; 1181 case AtomicExpr::AO__c11_atomic_fetch_xor: 1182 case AtomicExpr::AO__opencl_atomic_fetch_xor: 1183 case AtomicExpr::AO__atomic_fetch_xor: 1184 LibCallName = "__atomic_fetch_xor"; 1185 AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(), 1186 MemTy, E->getExprLoc(), TInfo.Width); 1187 break; 1188 case AtomicExpr::AO__atomic_min_fetch: 1189 PostOpMinMax = true; 1190 LLVM_FALLTHROUGH; 1191 case AtomicExpr::AO__c11_atomic_fetch_min: 1192 case AtomicExpr::AO__atomic_fetch_min: 1193 case AtomicExpr::AO__opencl_atomic_fetch_min: 1194 LibCallName = E->getValueType()->isSignedIntegerType() 1195 ? "__atomic_fetch_min" 1196 : "__atomic_fetch_umin"; 1197 AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(), 1198 LoweredMemTy, E->getExprLoc(), TInfo.Width); 1199 break; 1200 case AtomicExpr::AO__atomic_max_fetch: 1201 PostOpMinMax = true; 1202 LLVM_FALLTHROUGH; 1203 case AtomicExpr::AO__c11_atomic_fetch_max: 1204 case AtomicExpr::AO__atomic_fetch_max: 1205 case AtomicExpr::AO__opencl_atomic_fetch_max: 1206 LibCallName = E->getValueType()->isSignedIntegerType() 1207 ? "__atomic_fetch_max" 1208 : "__atomic_fetch_umax"; 1209 AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(), 1210 LoweredMemTy, E->getExprLoc(), TInfo.Width); 1211 break; 1212 // T __atomic_nand_fetch_N(T *mem, T val, int order) 1213 // T __atomic_fetch_nand_N(T *mem, T val, int order) 1214 case AtomicExpr::AO__atomic_nand_fetch: 1215 PostOp = llvm::Instruction::And; // the NOT is special cased below 1216 LLVM_FALLTHROUGH; 1217 case AtomicExpr::AO__c11_atomic_fetch_nand: 1218 case AtomicExpr::AO__atomic_fetch_nand: 1219 LibCallName = "__atomic_fetch_nand"; 1220 AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(), 1221 MemTy, E->getExprLoc(), TInfo.Width); 1222 break; 1223 } 1224 1225 if (E->isOpenCL()) { 1226 LibCallName = std::string("__opencl") + 1227 StringRef(LibCallName).drop_front(1).str(); 1228 1229 } 1230 // Optimized functions have the size in their name. 1231 if (UseOptimizedLibcall) 1232 LibCallName += "_" + llvm::utostr(Size); 1233 // By default, assume we return a value of the atomic type. 1234 if (!HaveRetTy) { 1235 if (UseOptimizedLibcall) { 1236 // Value is returned directly. 1237 // The function returns an appropriately sized integer type. 1238 RetTy = getContext().getIntTypeForBitwidth( 1239 getContext().toBits(TInfo.Width), /*Signed=*/false); 1240 } else { 1241 // Value is returned through parameter before the order. 1242 RetTy = getContext().VoidTy; 1243 Args.add(RValue::get(EmitCastToVoidPtr(Dest.getPointer())), 1244 getContext().VoidPtrTy); 1245 } 1246 } 1247 // order is always the last parameter 1248 Args.add(RValue::get(Order), 1249 getContext().IntTy); 1250 if (E->isOpenCL()) 1251 Args.add(RValue::get(Scope), getContext().IntTy); 1252 1253 // PostOp is only needed for the atomic_*_fetch operations, and 1254 // thus is only needed for and implemented in the 1255 // UseOptimizedLibcall codepath. 1256 assert(UseOptimizedLibcall || (!PostOp && !PostOpMinMax)); 1257 1258 RValue Res = emitAtomicLibcall(*this, LibCallName, RetTy, Args); 1259 // The value is returned directly from the libcall. 1260 if (E->isCmpXChg()) 1261 return Res; 1262 1263 // The value is returned directly for optimized libcalls but the expr 1264 // provided an out-param. 1265 if (UseOptimizedLibcall && Res.getScalarVal()) { 1266 llvm::Value *ResVal = Res.getScalarVal(); 1267 if (PostOpMinMax) { 1268 llvm::Value *LoadVal1 = Args[1].getRValue(*this).getScalarVal(); 1269 ResVal = EmitPostAtomicMinMax(Builder, E->getOp(), 1270 E->getValueType()->isSignedIntegerType(), 1271 ResVal, LoadVal1); 1272 } else if (PostOp) { 1273 llvm::Value *LoadVal1 = Args[1].getRValue(*this).getScalarVal(); 1274 ResVal = Builder.CreateBinOp(PostOp, ResVal, LoadVal1); 1275 } 1276 if (E->getOp() == AtomicExpr::AO__atomic_nand_fetch) 1277 ResVal = Builder.CreateNot(ResVal); 1278 1279 Builder.CreateStore( 1280 ResVal, 1281 Builder.CreateBitCast(Dest, ResVal->getType()->getPointerTo())); 1282 } 1283 1284 if (RValTy->isVoidType()) 1285 return RValue::get(nullptr); 1286 1287 return convertTempToRValue( 1288 Builder.CreateBitCast(Dest, ConvertTypeForMem(RValTy)->getPointerTo()), 1289 RValTy, E->getExprLoc()); 1290 } 1291 1292 bool IsStore = E->getOp() == AtomicExpr::AO__c11_atomic_store || 1293 E->getOp() == AtomicExpr::AO__opencl_atomic_store || 1294 E->getOp() == AtomicExpr::AO__atomic_store || 1295 E->getOp() == AtomicExpr::AO__atomic_store_n; 1296 bool IsLoad = E->getOp() == AtomicExpr::AO__c11_atomic_load || 1297 E->getOp() == AtomicExpr::AO__opencl_atomic_load || 1298 E->getOp() == AtomicExpr::AO__atomic_load || 1299 E->getOp() == AtomicExpr::AO__atomic_load_n; 1300 1301 if (isa<llvm::ConstantInt>(Order)) { 1302 auto ord = cast<llvm::ConstantInt>(Order)->getZExtValue(); 1303 // We should not ever get to a case where the ordering isn't a valid C ABI 1304 // value, but it's hard to enforce that in general. 1305 if (llvm::isValidAtomicOrderingCABI(ord)) 1306 switch ((llvm::AtomicOrderingCABI)ord) { 1307 case llvm::AtomicOrderingCABI::relaxed: 1308 EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size, 1309 llvm::AtomicOrdering::Monotonic, Scope); 1310 break; 1311 case llvm::AtomicOrderingCABI::consume: 1312 case llvm::AtomicOrderingCABI::acquire: 1313 if (IsStore) 1314 break; // Avoid crashing on code with undefined behavior 1315 EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size, 1316 llvm::AtomicOrdering::Acquire, Scope); 1317 break; 1318 case llvm::AtomicOrderingCABI::release: 1319 if (IsLoad) 1320 break; // Avoid crashing on code with undefined behavior 1321 EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size, 1322 llvm::AtomicOrdering::Release, Scope); 1323 break; 1324 case llvm::AtomicOrderingCABI::acq_rel: 1325 if (IsLoad || IsStore) 1326 break; // Avoid crashing on code with undefined behavior 1327 EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size, 1328 llvm::AtomicOrdering::AcquireRelease, Scope); 1329 break; 1330 case llvm::AtomicOrderingCABI::seq_cst: 1331 EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size, 1332 llvm::AtomicOrdering::SequentiallyConsistent, Scope); 1333 break; 1334 } 1335 if (RValTy->isVoidType()) 1336 return RValue::get(nullptr); 1337 1338 return convertTempToRValue( 1339 Builder.CreateBitCast(Dest, ConvertTypeForMem(RValTy)->getPointerTo( 1340 Dest.getAddressSpace())), 1341 RValTy, E->getExprLoc()); 1342 } 1343 1344 // Long case, when Order isn't obviously constant. 1345 1346 // Create all the relevant BB's 1347 llvm::BasicBlock *MonotonicBB = nullptr, *AcquireBB = nullptr, 1348 *ReleaseBB = nullptr, *AcqRelBB = nullptr, 1349 *SeqCstBB = nullptr; 1350 MonotonicBB = createBasicBlock("monotonic", CurFn); 1351 if (!IsStore) 1352 AcquireBB = createBasicBlock("acquire", CurFn); 1353 if (!IsLoad) 1354 ReleaseBB = createBasicBlock("release", CurFn); 1355 if (!IsLoad && !IsStore) 1356 AcqRelBB = createBasicBlock("acqrel", CurFn); 1357 SeqCstBB = createBasicBlock("seqcst", CurFn); 1358 llvm::BasicBlock *ContBB = createBasicBlock("atomic.continue", CurFn); 1359 1360 // Create the switch for the split 1361 // MonotonicBB is arbitrarily chosen as the default case; in practice, this 1362 // doesn't matter unless someone is crazy enough to use something that 1363 // doesn't fold to a constant for the ordering. 1364 Order = Builder.CreateIntCast(Order, Builder.getInt32Ty(), false); 1365 llvm::SwitchInst *SI = Builder.CreateSwitch(Order, MonotonicBB); 1366 1367 // Emit all the different atomics 1368 Builder.SetInsertPoint(MonotonicBB); 1369 EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size, 1370 llvm::AtomicOrdering::Monotonic, Scope); 1371 Builder.CreateBr(ContBB); 1372 if (!IsStore) { 1373 Builder.SetInsertPoint(AcquireBB); 1374 EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size, 1375 llvm::AtomicOrdering::Acquire, Scope); 1376 Builder.CreateBr(ContBB); 1377 SI->addCase(Builder.getInt32((int)llvm::AtomicOrderingCABI::consume), 1378 AcquireBB); 1379 SI->addCase(Builder.getInt32((int)llvm::AtomicOrderingCABI::acquire), 1380 AcquireBB); 1381 } 1382 if (!IsLoad) { 1383 Builder.SetInsertPoint(ReleaseBB); 1384 EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size, 1385 llvm::AtomicOrdering::Release, Scope); 1386 Builder.CreateBr(ContBB); 1387 SI->addCase(Builder.getInt32((int)llvm::AtomicOrderingCABI::release), 1388 ReleaseBB); 1389 } 1390 if (!IsLoad && !IsStore) { 1391 Builder.SetInsertPoint(AcqRelBB); 1392 EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size, 1393 llvm::AtomicOrdering::AcquireRelease, Scope); 1394 Builder.CreateBr(ContBB); 1395 SI->addCase(Builder.getInt32((int)llvm::AtomicOrderingCABI::acq_rel), 1396 AcqRelBB); 1397 } 1398 Builder.SetInsertPoint(SeqCstBB); 1399 EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size, 1400 llvm::AtomicOrdering::SequentiallyConsistent, Scope); 1401 Builder.CreateBr(ContBB); 1402 SI->addCase(Builder.getInt32((int)llvm::AtomicOrderingCABI::seq_cst), 1403 SeqCstBB); 1404 1405 // Cleanup and return 1406 Builder.SetInsertPoint(ContBB); 1407 if (RValTy->isVoidType()) 1408 return RValue::get(nullptr); 1409 1410 assert(Atomics.getValueSizeInBits() <= Atomics.getAtomicSizeInBits()); 1411 return convertTempToRValue( 1412 Builder.CreateBitCast(Dest, ConvertTypeForMem(RValTy)->getPointerTo( 1413 Dest.getAddressSpace())), 1414 RValTy, E->getExprLoc()); 1415 } 1416 1417 Address AtomicInfo::emitCastToAtomicIntPointer(Address addr) const { 1418 unsigned addrspace = 1419 cast<llvm::PointerType>(addr.getPointer()->getType())->getAddressSpace(); 1420 llvm::IntegerType *ty = 1421 llvm::IntegerType::get(CGF.getLLVMContext(), AtomicSizeInBits); 1422 return CGF.Builder.CreateBitCast(addr, ty->getPointerTo(addrspace)); 1423 } 1424 1425 Address AtomicInfo::convertToAtomicIntPointer(Address Addr) const { 1426 llvm::Type *Ty = Addr.getElementType(); 1427 uint64_t SourceSizeInBits = CGF.CGM.getDataLayout().getTypeSizeInBits(Ty); 1428 if (SourceSizeInBits != AtomicSizeInBits) { 1429 Address Tmp = CreateTempAlloca(); 1430 CGF.Builder.CreateMemCpy(Tmp, Addr, 1431 std::min(AtomicSizeInBits, SourceSizeInBits) / 8); 1432 Addr = Tmp; 1433 } 1434 1435 return emitCastToAtomicIntPointer(Addr); 1436 } 1437 1438 RValue AtomicInfo::convertAtomicTempToRValue(Address addr, 1439 AggValueSlot resultSlot, 1440 SourceLocation loc, 1441 bool asValue) const { 1442 if (LVal.isSimple()) { 1443 if (EvaluationKind == TEK_Aggregate) 1444 return resultSlot.asRValue(); 1445 1446 // Drill into the padding structure if we have one. 1447 if (hasPadding()) 1448 addr = CGF.Builder.CreateStructGEP(addr, 0); 1449 1450 // Otherwise, just convert the temporary to an r-value using the 1451 // normal conversion routine. 1452 return CGF.convertTempToRValue(addr, getValueType(), loc); 1453 } 1454 if (!asValue) 1455 // Get RValue from temp memory as atomic for non-simple lvalues 1456 return RValue::get(CGF.Builder.CreateLoad(addr)); 1457 if (LVal.isBitField()) 1458 return CGF.EmitLoadOfBitfieldLValue( 1459 LValue::MakeBitfield(addr, LVal.getBitFieldInfo(), LVal.getType(), 1460 LVal.getBaseInfo(), TBAAAccessInfo()), loc); 1461 if (LVal.isVectorElt()) 1462 return CGF.EmitLoadOfLValue( 1463 LValue::MakeVectorElt(addr, LVal.getVectorIdx(), LVal.getType(), 1464 LVal.getBaseInfo(), TBAAAccessInfo()), loc); 1465 assert(LVal.isExtVectorElt()); 1466 return CGF.EmitLoadOfExtVectorElementLValue(LValue::MakeExtVectorElt( 1467 addr, LVal.getExtVectorElts(), LVal.getType(), 1468 LVal.getBaseInfo(), TBAAAccessInfo())); 1469 } 1470 1471 RValue AtomicInfo::ConvertIntToValueOrAtomic(llvm::Value *IntVal, 1472 AggValueSlot ResultSlot, 1473 SourceLocation Loc, 1474 bool AsValue) const { 1475 // Try not to in some easy cases. 1476 assert(IntVal->getType()->isIntegerTy() && "Expected integer value"); 1477 if (getEvaluationKind() == TEK_Scalar && 1478 (((!LVal.isBitField() || 1479 LVal.getBitFieldInfo().Size == ValueSizeInBits) && 1480 !hasPadding()) || 1481 !AsValue)) { 1482 auto *ValTy = AsValue 1483 ? CGF.ConvertTypeForMem(ValueTy) 1484 : getAtomicAddress().getType()->getPointerElementType(); 1485 if (ValTy->isIntegerTy()) { 1486 assert(IntVal->getType() == ValTy && "Different integer types."); 1487 return RValue::get(CGF.EmitFromMemory(IntVal, ValueTy)); 1488 } else if (ValTy->isPointerTy()) 1489 return RValue::get(CGF.Builder.CreateIntToPtr(IntVal, ValTy)); 1490 else if (llvm::CastInst::isBitCastable(IntVal->getType(), ValTy)) 1491 return RValue::get(CGF.Builder.CreateBitCast(IntVal, ValTy)); 1492 } 1493 1494 // Create a temporary. This needs to be big enough to hold the 1495 // atomic integer. 1496 Address Temp = Address::invalid(); 1497 bool TempIsVolatile = false; 1498 if (AsValue && getEvaluationKind() == TEK_Aggregate) { 1499 assert(!ResultSlot.isIgnored()); 1500 Temp = ResultSlot.getAddress(); 1501 TempIsVolatile = ResultSlot.isVolatile(); 1502 } else { 1503 Temp = CreateTempAlloca(); 1504 } 1505 1506 // Slam the integer into the temporary. 1507 Address CastTemp = emitCastToAtomicIntPointer(Temp); 1508 CGF.Builder.CreateStore(IntVal, CastTemp) 1509 ->setVolatile(TempIsVolatile); 1510 1511 return convertAtomicTempToRValue(Temp, ResultSlot, Loc, AsValue); 1512 } 1513 1514 void AtomicInfo::EmitAtomicLoadLibcall(llvm::Value *AddForLoaded, 1515 llvm::AtomicOrdering AO, bool) { 1516 // void __atomic_load(size_t size, void *mem, void *return, int order); 1517 CallArgList Args; 1518 Args.add(RValue::get(getAtomicSizeValue()), CGF.getContext().getSizeType()); 1519 Args.add(RValue::get(CGF.EmitCastToVoidPtr(getAtomicPointer())), 1520 CGF.getContext().VoidPtrTy); 1521 Args.add(RValue::get(CGF.EmitCastToVoidPtr(AddForLoaded)), 1522 CGF.getContext().VoidPtrTy); 1523 Args.add( 1524 RValue::get(llvm::ConstantInt::get(CGF.IntTy, (int)llvm::toCABI(AO))), 1525 CGF.getContext().IntTy); 1526 emitAtomicLibcall(CGF, "__atomic_load", CGF.getContext().VoidTy, Args); 1527 } 1528 1529 llvm::Value *AtomicInfo::EmitAtomicLoadOp(llvm::AtomicOrdering AO, 1530 bool IsVolatile) { 1531 // Okay, we're doing this natively. 1532 Address Addr = getAtomicAddressAsAtomicIntPointer(); 1533 llvm::LoadInst *Load = CGF.Builder.CreateLoad(Addr, "atomic-load"); 1534 Load->setAtomic(AO); 1535 1536 // Other decoration. 1537 if (IsVolatile) 1538 Load->setVolatile(true); 1539 CGF.CGM.DecorateInstructionWithTBAA(Load, LVal.getTBAAInfo()); 1540 return Load; 1541 } 1542 1543 /// An LValue is a candidate for having its loads and stores be made atomic if 1544 /// we are operating under /volatile:ms *and* the LValue itself is volatile and 1545 /// performing such an operation can be performed without a libcall. 1546 bool CodeGenFunction::LValueIsSuitableForInlineAtomic(LValue LV) { 1547 if (!CGM.getCodeGenOpts().MSVolatile) return false; 1548 AtomicInfo AI(*this, LV); 1549 bool IsVolatile = LV.isVolatile() || hasVolatileMember(LV.getType()); 1550 // An atomic is inline if we don't need to use a libcall. 1551 bool AtomicIsInline = !AI.shouldUseLibcall(); 1552 // MSVC doesn't seem to do this for types wider than a pointer. 1553 if (getContext().getTypeSize(LV.getType()) > 1554 getContext().getTypeSize(getContext().getIntPtrType())) 1555 return false; 1556 return IsVolatile && AtomicIsInline; 1557 } 1558 1559 RValue CodeGenFunction::EmitAtomicLoad(LValue LV, SourceLocation SL, 1560 AggValueSlot Slot) { 1561 llvm::AtomicOrdering AO; 1562 bool IsVolatile = LV.isVolatileQualified(); 1563 if (LV.getType()->isAtomicType()) { 1564 AO = llvm::AtomicOrdering::SequentiallyConsistent; 1565 } else { 1566 AO = llvm::AtomicOrdering::Acquire; 1567 IsVolatile = true; 1568 } 1569 return EmitAtomicLoad(LV, SL, AO, IsVolatile, Slot); 1570 } 1571 1572 RValue AtomicInfo::EmitAtomicLoad(AggValueSlot ResultSlot, SourceLocation Loc, 1573 bool AsValue, llvm::AtomicOrdering AO, 1574 bool IsVolatile) { 1575 // Check whether we should use a library call. 1576 if (shouldUseLibcall()) { 1577 Address TempAddr = Address::invalid(); 1578 if (LVal.isSimple() && !ResultSlot.isIgnored()) { 1579 assert(getEvaluationKind() == TEK_Aggregate); 1580 TempAddr = ResultSlot.getAddress(); 1581 } else 1582 TempAddr = CreateTempAlloca(); 1583 1584 EmitAtomicLoadLibcall(TempAddr.getPointer(), AO, IsVolatile); 1585 1586 // Okay, turn that back into the original value or whole atomic (for 1587 // non-simple lvalues) type. 1588 return convertAtomicTempToRValue(TempAddr, ResultSlot, Loc, AsValue); 1589 } 1590 1591 // Okay, we're doing this natively. 1592 auto *Load = EmitAtomicLoadOp(AO, IsVolatile); 1593 1594 // If we're ignoring an aggregate return, don't do anything. 1595 if (getEvaluationKind() == TEK_Aggregate && ResultSlot.isIgnored()) 1596 return RValue::getAggregate(Address::invalid(), false); 1597 1598 // Okay, turn that back into the original value or atomic (for non-simple 1599 // lvalues) type. 1600 return ConvertIntToValueOrAtomic(Load, ResultSlot, Loc, AsValue); 1601 } 1602 1603 /// Emit a load from an l-value of atomic type. Note that the r-value 1604 /// we produce is an r-value of the atomic *value* type. 1605 RValue CodeGenFunction::EmitAtomicLoad(LValue src, SourceLocation loc, 1606 llvm::AtomicOrdering AO, bool IsVolatile, 1607 AggValueSlot resultSlot) { 1608 AtomicInfo Atomics(*this, src); 1609 return Atomics.EmitAtomicLoad(resultSlot, loc, /*AsValue=*/true, AO, 1610 IsVolatile); 1611 } 1612 1613 /// Copy an r-value into memory as part of storing to an atomic type. 1614 /// This needs to create a bit-pattern suitable for atomic operations. 1615 void AtomicInfo::emitCopyIntoMemory(RValue rvalue) const { 1616 assert(LVal.isSimple()); 1617 // If we have an r-value, the rvalue should be of the atomic type, 1618 // which means that the caller is responsible for having zeroed 1619 // any padding. Just do an aggregate copy of that type. 1620 if (rvalue.isAggregate()) { 1621 LValue Dest = CGF.MakeAddrLValue(getAtomicAddress(), getAtomicType()); 1622 LValue Src = CGF.MakeAddrLValue(rvalue.getAggregateAddress(), 1623 getAtomicType()); 1624 bool IsVolatile = rvalue.isVolatileQualified() || 1625 LVal.isVolatileQualified(); 1626 CGF.EmitAggregateCopy(Dest, Src, getAtomicType(), 1627 AggValueSlot::DoesNotOverlap, IsVolatile); 1628 return; 1629 } 1630 1631 // Okay, otherwise we're copying stuff. 1632 1633 // Zero out the buffer if necessary. 1634 emitMemSetZeroIfNecessary(); 1635 1636 // Drill past the padding if present. 1637 LValue TempLVal = projectValue(); 1638 1639 // Okay, store the rvalue in. 1640 if (rvalue.isScalar()) { 1641 CGF.EmitStoreOfScalar(rvalue.getScalarVal(), TempLVal, /*init*/ true); 1642 } else { 1643 CGF.EmitStoreOfComplex(rvalue.getComplexVal(), TempLVal, /*init*/ true); 1644 } 1645 } 1646 1647 1648 /// Materialize an r-value into memory for the purposes of storing it 1649 /// to an atomic type. 1650 Address AtomicInfo::materializeRValue(RValue rvalue) const { 1651 // Aggregate r-values are already in memory, and EmitAtomicStore 1652 // requires them to be values of the atomic type. 1653 if (rvalue.isAggregate()) 1654 return rvalue.getAggregateAddress(); 1655 1656 // Otherwise, make a temporary and materialize into it. 1657 LValue TempLV = CGF.MakeAddrLValue(CreateTempAlloca(), getAtomicType()); 1658 AtomicInfo Atomics(CGF, TempLV); 1659 Atomics.emitCopyIntoMemory(rvalue); 1660 return TempLV.getAddress(CGF); 1661 } 1662 1663 llvm::Value *AtomicInfo::convertRValueToInt(RValue RVal) const { 1664 // If we've got a scalar value of the right size, try to avoid going 1665 // through memory. 1666 if (RVal.isScalar() && (!hasPadding() || !LVal.isSimple())) { 1667 llvm::Value *Value = RVal.getScalarVal(); 1668 if (isa<llvm::IntegerType>(Value->getType())) 1669 return CGF.EmitToMemory(Value, ValueTy); 1670 else { 1671 llvm::IntegerType *InputIntTy = llvm::IntegerType::get( 1672 CGF.getLLVMContext(), 1673 LVal.isSimple() ? getValueSizeInBits() : getAtomicSizeInBits()); 1674 if (isa<llvm::PointerType>(Value->getType())) 1675 return CGF.Builder.CreatePtrToInt(Value, InputIntTy); 1676 else if (llvm::BitCastInst::isBitCastable(Value->getType(), InputIntTy)) 1677 return CGF.Builder.CreateBitCast(Value, InputIntTy); 1678 } 1679 } 1680 // Otherwise, we need to go through memory. 1681 // Put the r-value in memory. 1682 Address Addr = materializeRValue(RVal); 1683 1684 // Cast the temporary to the atomic int type and pull a value out. 1685 Addr = emitCastToAtomicIntPointer(Addr); 1686 return CGF.Builder.CreateLoad(Addr); 1687 } 1688 1689 std::pair<llvm::Value *, llvm::Value *> AtomicInfo::EmitAtomicCompareExchangeOp( 1690 llvm::Value *ExpectedVal, llvm::Value *DesiredVal, 1691 llvm::AtomicOrdering Success, llvm::AtomicOrdering Failure, bool IsWeak) { 1692 // Do the atomic store. 1693 Address Addr = getAtomicAddressAsAtomicIntPointer(); 1694 auto *Inst = CGF.Builder.CreateAtomicCmpXchg(Addr.getPointer(), 1695 ExpectedVal, DesiredVal, 1696 Success, Failure); 1697 // Other decoration. 1698 Inst->setVolatile(LVal.isVolatileQualified()); 1699 Inst->setWeak(IsWeak); 1700 1701 // Okay, turn that back into the original value type. 1702 auto *PreviousVal = CGF.Builder.CreateExtractValue(Inst, /*Idxs=*/0); 1703 auto *SuccessFailureVal = CGF.Builder.CreateExtractValue(Inst, /*Idxs=*/1); 1704 return std::make_pair(PreviousVal, SuccessFailureVal); 1705 } 1706 1707 llvm::Value * 1708 AtomicInfo::EmitAtomicCompareExchangeLibcall(llvm::Value *ExpectedAddr, 1709 llvm::Value *DesiredAddr, 1710 llvm::AtomicOrdering Success, 1711 llvm::AtomicOrdering Failure) { 1712 // bool __atomic_compare_exchange(size_t size, void *obj, void *expected, 1713 // void *desired, int success, int failure); 1714 CallArgList Args; 1715 Args.add(RValue::get(getAtomicSizeValue()), CGF.getContext().getSizeType()); 1716 Args.add(RValue::get(CGF.EmitCastToVoidPtr(getAtomicPointer())), 1717 CGF.getContext().VoidPtrTy); 1718 Args.add(RValue::get(CGF.EmitCastToVoidPtr(ExpectedAddr)), 1719 CGF.getContext().VoidPtrTy); 1720 Args.add(RValue::get(CGF.EmitCastToVoidPtr(DesiredAddr)), 1721 CGF.getContext().VoidPtrTy); 1722 Args.add(RValue::get( 1723 llvm::ConstantInt::get(CGF.IntTy, (int)llvm::toCABI(Success))), 1724 CGF.getContext().IntTy); 1725 Args.add(RValue::get( 1726 llvm::ConstantInt::get(CGF.IntTy, (int)llvm::toCABI(Failure))), 1727 CGF.getContext().IntTy); 1728 auto SuccessFailureRVal = emitAtomicLibcall(CGF, "__atomic_compare_exchange", 1729 CGF.getContext().BoolTy, Args); 1730 1731 return SuccessFailureRVal.getScalarVal(); 1732 } 1733 1734 std::pair<RValue, llvm::Value *> AtomicInfo::EmitAtomicCompareExchange( 1735 RValue Expected, RValue Desired, llvm::AtomicOrdering Success, 1736 llvm::AtomicOrdering Failure, bool IsWeak) { 1737 // Check whether we should use a library call. 1738 if (shouldUseLibcall()) { 1739 // Produce a source address. 1740 Address ExpectedAddr = materializeRValue(Expected); 1741 Address DesiredAddr = materializeRValue(Desired); 1742 auto *Res = EmitAtomicCompareExchangeLibcall(ExpectedAddr.getPointer(), 1743 DesiredAddr.getPointer(), 1744 Success, Failure); 1745 return std::make_pair( 1746 convertAtomicTempToRValue(ExpectedAddr, AggValueSlot::ignored(), 1747 SourceLocation(), /*AsValue=*/false), 1748 Res); 1749 } 1750 1751 // If we've got a scalar value of the right size, try to avoid going 1752 // through memory. 1753 auto *ExpectedVal = convertRValueToInt(Expected); 1754 auto *DesiredVal = convertRValueToInt(Desired); 1755 auto Res = EmitAtomicCompareExchangeOp(ExpectedVal, DesiredVal, Success, 1756 Failure, IsWeak); 1757 return std::make_pair( 1758 ConvertIntToValueOrAtomic(Res.first, AggValueSlot::ignored(), 1759 SourceLocation(), /*AsValue=*/false), 1760 Res.second); 1761 } 1762 1763 static void 1764 EmitAtomicUpdateValue(CodeGenFunction &CGF, AtomicInfo &Atomics, RValue OldRVal, 1765 const llvm::function_ref<RValue(RValue)> &UpdateOp, 1766 Address DesiredAddr) { 1767 RValue UpRVal; 1768 LValue AtomicLVal = Atomics.getAtomicLValue(); 1769 LValue DesiredLVal; 1770 if (AtomicLVal.isSimple()) { 1771 UpRVal = OldRVal; 1772 DesiredLVal = CGF.MakeAddrLValue(DesiredAddr, AtomicLVal.getType()); 1773 } else { 1774 // Build new lvalue for temp address. 1775 Address Ptr = Atomics.materializeRValue(OldRVal); 1776 LValue UpdateLVal; 1777 if (AtomicLVal.isBitField()) { 1778 UpdateLVal = 1779 LValue::MakeBitfield(Ptr, AtomicLVal.getBitFieldInfo(), 1780 AtomicLVal.getType(), 1781 AtomicLVal.getBaseInfo(), 1782 AtomicLVal.getTBAAInfo()); 1783 DesiredLVal = 1784 LValue::MakeBitfield(DesiredAddr, AtomicLVal.getBitFieldInfo(), 1785 AtomicLVal.getType(), AtomicLVal.getBaseInfo(), 1786 AtomicLVal.getTBAAInfo()); 1787 } else if (AtomicLVal.isVectorElt()) { 1788 UpdateLVal = LValue::MakeVectorElt(Ptr, AtomicLVal.getVectorIdx(), 1789 AtomicLVal.getType(), 1790 AtomicLVal.getBaseInfo(), 1791 AtomicLVal.getTBAAInfo()); 1792 DesiredLVal = LValue::MakeVectorElt( 1793 DesiredAddr, AtomicLVal.getVectorIdx(), AtomicLVal.getType(), 1794 AtomicLVal.getBaseInfo(), AtomicLVal.getTBAAInfo()); 1795 } else { 1796 assert(AtomicLVal.isExtVectorElt()); 1797 UpdateLVal = LValue::MakeExtVectorElt(Ptr, AtomicLVal.getExtVectorElts(), 1798 AtomicLVal.getType(), 1799 AtomicLVal.getBaseInfo(), 1800 AtomicLVal.getTBAAInfo()); 1801 DesiredLVal = LValue::MakeExtVectorElt( 1802 DesiredAddr, AtomicLVal.getExtVectorElts(), AtomicLVal.getType(), 1803 AtomicLVal.getBaseInfo(), AtomicLVal.getTBAAInfo()); 1804 } 1805 UpRVal = CGF.EmitLoadOfLValue(UpdateLVal, SourceLocation()); 1806 } 1807 // Store new value in the corresponding memory area. 1808 RValue NewRVal = UpdateOp(UpRVal); 1809 if (NewRVal.isScalar()) { 1810 CGF.EmitStoreThroughLValue(NewRVal, DesiredLVal); 1811 } else { 1812 assert(NewRVal.isComplex()); 1813 CGF.EmitStoreOfComplex(NewRVal.getComplexVal(), DesiredLVal, 1814 /*isInit=*/false); 1815 } 1816 } 1817 1818 void AtomicInfo::EmitAtomicUpdateLibcall( 1819 llvm::AtomicOrdering AO, const llvm::function_ref<RValue(RValue)> &UpdateOp, 1820 bool IsVolatile) { 1821 auto Failure = llvm::AtomicCmpXchgInst::getStrongestFailureOrdering(AO); 1822 1823 Address ExpectedAddr = CreateTempAlloca(); 1824 1825 EmitAtomicLoadLibcall(ExpectedAddr.getPointer(), AO, IsVolatile); 1826 auto *ContBB = CGF.createBasicBlock("atomic_cont"); 1827 auto *ExitBB = CGF.createBasicBlock("atomic_exit"); 1828 CGF.EmitBlock(ContBB); 1829 Address DesiredAddr = CreateTempAlloca(); 1830 if ((LVal.isBitField() && BFI.Size != ValueSizeInBits) || 1831 requiresMemSetZero(getAtomicAddress().getElementType())) { 1832 auto *OldVal = CGF.Builder.CreateLoad(ExpectedAddr); 1833 CGF.Builder.CreateStore(OldVal, DesiredAddr); 1834 } 1835 auto OldRVal = convertAtomicTempToRValue(ExpectedAddr, 1836 AggValueSlot::ignored(), 1837 SourceLocation(), /*AsValue=*/false); 1838 EmitAtomicUpdateValue(CGF, *this, OldRVal, UpdateOp, DesiredAddr); 1839 auto *Res = 1840 EmitAtomicCompareExchangeLibcall(ExpectedAddr.getPointer(), 1841 DesiredAddr.getPointer(), 1842 AO, Failure); 1843 CGF.Builder.CreateCondBr(Res, ExitBB, ContBB); 1844 CGF.EmitBlock(ExitBB, /*IsFinished=*/true); 1845 } 1846 1847 void AtomicInfo::EmitAtomicUpdateOp( 1848 llvm::AtomicOrdering AO, const llvm::function_ref<RValue(RValue)> &UpdateOp, 1849 bool IsVolatile) { 1850 auto Failure = llvm::AtomicCmpXchgInst::getStrongestFailureOrdering(AO); 1851 1852 // Do the atomic load. 1853 auto *OldVal = EmitAtomicLoadOp(Failure, IsVolatile); 1854 // For non-simple lvalues perform compare-and-swap procedure. 1855 auto *ContBB = CGF.createBasicBlock("atomic_cont"); 1856 auto *ExitBB = CGF.createBasicBlock("atomic_exit"); 1857 auto *CurBB = CGF.Builder.GetInsertBlock(); 1858 CGF.EmitBlock(ContBB); 1859 llvm::PHINode *PHI = CGF.Builder.CreatePHI(OldVal->getType(), 1860 /*NumReservedValues=*/2); 1861 PHI->addIncoming(OldVal, CurBB); 1862 Address NewAtomicAddr = CreateTempAlloca(); 1863 Address NewAtomicIntAddr = emitCastToAtomicIntPointer(NewAtomicAddr); 1864 if ((LVal.isBitField() && BFI.Size != ValueSizeInBits) || 1865 requiresMemSetZero(getAtomicAddress().getElementType())) { 1866 CGF.Builder.CreateStore(PHI, NewAtomicIntAddr); 1867 } 1868 auto OldRVal = ConvertIntToValueOrAtomic(PHI, AggValueSlot::ignored(), 1869 SourceLocation(), /*AsValue=*/false); 1870 EmitAtomicUpdateValue(CGF, *this, OldRVal, UpdateOp, NewAtomicAddr); 1871 auto *DesiredVal = CGF.Builder.CreateLoad(NewAtomicIntAddr); 1872 // Try to write new value using cmpxchg operation. 1873 auto Res = EmitAtomicCompareExchangeOp(PHI, DesiredVal, AO, Failure); 1874 PHI->addIncoming(Res.first, CGF.Builder.GetInsertBlock()); 1875 CGF.Builder.CreateCondBr(Res.second, ExitBB, ContBB); 1876 CGF.EmitBlock(ExitBB, /*IsFinished=*/true); 1877 } 1878 1879 static void EmitAtomicUpdateValue(CodeGenFunction &CGF, AtomicInfo &Atomics, 1880 RValue UpdateRVal, Address DesiredAddr) { 1881 LValue AtomicLVal = Atomics.getAtomicLValue(); 1882 LValue DesiredLVal; 1883 // Build new lvalue for temp address. 1884 if (AtomicLVal.isBitField()) { 1885 DesiredLVal = 1886 LValue::MakeBitfield(DesiredAddr, AtomicLVal.getBitFieldInfo(), 1887 AtomicLVal.getType(), AtomicLVal.getBaseInfo(), 1888 AtomicLVal.getTBAAInfo()); 1889 } else if (AtomicLVal.isVectorElt()) { 1890 DesiredLVal = 1891 LValue::MakeVectorElt(DesiredAddr, AtomicLVal.getVectorIdx(), 1892 AtomicLVal.getType(), AtomicLVal.getBaseInfo(), 1893 AtomicLVal.getTBAAInfo()); 1894 } else { 1895 assert(AtomicLVal.isExtVectorElt()); 1896 DesiredLVal = LValue::MakeExtVectorElt( 1897 DesiredAddr, AtomicLVal.getExtVectorElts(), AtomicLVal.getType(), 1898 AtomicLVal.getBaseInfo(), AtomicLVal.getTBAAInfo()); 1899 } 1900 // Store new value in the corresponding memory area. 1901 assert(UpdateRVal.isScalar()); 1902 CGF.EmitStoreThroughLValue(UpdateRVal, DesiredLVal); 1903 } 1904 1905 void AtomicInfo::EmitAtomicUpdateLibcall(llvm::AtomicOrdering AO, 1906 RValue UpdateRVal, bool IsVolatile) { 1907 auto Failure = llvm::AtomicCmpXchgInst::getStrongestFailureOrdering(AO); 1908 1909 Address ExpectedAddr = CreateTempAlloca(); 1910 1911 EmitAtomicLoadLibcall(ExpectedAddr.getPointer(), AO, IsVolatile); 1912 auto *ContBB = CGF.createBasicBlock("atomic_cont"); 1913 auto *ExitBB = CGF.createBasicBlock("atomic_exit"); 1914 CGF.EmitBlock(ContBB); 1915 Address DesiredAddr = CreateTempAlloca(); 1916 if ((LVal.isBitField() && BFI.Size != ValueSizeInBits) || 1917 requiresMemSetZero(getAtomicAddress().getElementType())) { 1918 auto *OldVal = CGF.Builder.CreateLoad(ExpectedAddr); 1919 CGF.Builder.CreateStore(OldVal, DesiredAddr); 1920 } 1921 EmitAtomicUpdateValue(CGF, *this, UpdateRVal, DesiredAddr); 1922 auto *Res = 1923 EmitAtomicCompareExchangeLibcall(ExpectedAddr.getPointer(), 1924 DesiredAddr.getPointer(), 1925 AO, Failure); 1926 CGF.Builder.CreateCondBr(Res, ExitBB, ContBB); 1927 CGF.EmitBlock(ExitBB, /*IsFinished=*/true); 1928 } 1929 1930 void AtomicInfo::EmitAtomicUpdateOp(llvm::AtomicOrdering AO, RValue UpdateRVal, 1931 bool IsVolatile) { 1932 auto Failure = llvm::AtomicCmpXchgInst::getStrongestFailureOrdering(AO); 1933 1934 // Do the atomic load. 1935 auto *OldVal = EmitAtomicLoadOp(Failure, IsVolatile); 1936 // For non-simple lvalues perform compare-and-swap procedure. 1937 auto *ContBB = CGF.createBasicBlock("atomic_cont"); 1938 auto *ExitBB = CGF.createBasicBlock("atomic_exit"); 1939 auto *CurBB = CGF.Builder.GetInsertBlock(); 1940 CGF.EmitBlock(ContBB); 1941 llvm::PHINode *PHI = CGF.Builder.CreatePHI(OldVal->getType(), 1942 /*NumReservedValues=*/2); 1943 PHI->addIncoming(OldVal, CurBB); 1944 Address NewAtomicAddr = CreateTempAlloca(); 1945 Address NewAtomicIntAddr = emitCastToAtomicIntPointer(NewAtomicAddr); 1946 if ((LVal.isBitField() && BFI.Size != ValueSizeInBits) || 1947 requiresMemSetZero(getAtomicAddress().getElementType())) { 1948 CGF.Builder.CreateStore(PHI, NewAtomicIntAddr); 1949 } 1950 EmitAtomicUpdateValue(CGF, *this, UpdateRVal, NewAtomicAddr); 1951 auto *DesiredVal = CGF.Builder.CreateLoad(NewAtomicIntAddr); 1952 // Try to write new value using cmpxchg operation. 1953 auto Res = EmitAtomicCompareExchangeOp(PHI, DesiredVal, AO, Failure); 1954 PHI->addIncoming(Res.first, CGF.Builder.GetInsertBlock()); 1955 CGF.Builder.CreateCondBr(Res.second, ExitBB, ContBB); 1956 CGF.EmitBlock(ExitBB, /*IsFinished=*/true); 1957 } 1958 1959 void AtomicInfo::EmitAtomicUpdate( 1960 llvm::AtomicOrdering AO, const llvm::function_ref<RValue(RValue)> &UpdateOp, 1961 bool IsVolatile) { 1962 if (shouldUseLibcall()) { 1963 EmitAtomicUpdateLibcall(AO, UpdateOp, IsVolatile); 1964 } else { 1965 EmitAtomicUpdateOp(AO, UpdateOp, IsVolatile); 1966 } 1967 } 1968 1969 void AtomicInfo::EmitAtomicUpdate(llvm::AtomicOrdering AO, RValue UpdateRVal, 1970 bool IsVolatile) { 1971 if (shouldUseLibcall()) { 1972 EmitAtomicUpdateLibcall(AO, UpdateRVal, IsVolatile); 1973 } else { 1974 EmitAtomicUpdateOp(AO, UpdateRVal, IsVolatile); 1975 } 1976 } 1977 1978 void CodeGenFunction::EmitAtomicStore(RValue rvalue, LValue lvalue, 1979 bool isInit) { 1980 bool IsVolatile = lvalue.isVolatileQualified(); 1981 llvm::AtomicOrdering AO; 1982 if (lvalue.getType()->isAtomicType()) { 1983 AO = llvm::AtomicOrdering::SequentiallyConsistent; 1984 } else { 1985 AO = llvm::AtomicOrdering::Release; 1986 IsVolatile = true; 1987 } 1988 return EmitAtomicStore(rvalue, lvalue, AO, IsVolatile, isInit); 1989 } 1990 1991 /// Emit a store to an l-value of atomic type. 1992 /// 1993 /// Note that the r-value is expected to be an r-value *of the atomic 1994 /// type*; this means that for aggregate r-values, it should include 1995 /// storage for any padding that was necessary. 1996 void CodeGenFunction::EmitAtomicStore(RValue rvalue, LValue dest, 1997 llvm::AtomicOrdering AO, bool IsVolatile, 1998 bool isInit) { 1999 // If this is an aggregate r-value, it should agree in type except 2000 // maybe for address-space qualification. 2001 assert(!rvalue.isAggregate() || 2002 rvalue.getAggregateAddress().getElementType() == 2003 dest.getAddress(*this).getElementType()); 2004 2005 AtomicInfo atomics(*this, dest); 2006 LValue LVal = atomics.getAtomicLValue(); 2007 2008 // If this is an initialization, just put the value there normally. 2009 if (LVal.isSimple()) { 2010 if (isInit) { 2011 atomics.emitCopyIntoMemory(rvalue); 2012 return; 2013 } 2014 2015 // Check whether we should use a library call. 2016 if (atomics.shouldUseLibcall()) { 2017 // Produce a source address. 2018 Address srcAddr = atomics.materializeRValue(rvalue); 2019 2020 // void __atomic_store(size_t size, void *mem, void *val, int order) 2021 CallArgList args; 2022 args.add(RValue::get(atomics.getAtomicSizeValue()), 2023 getContext().getSizeType()); 2024 args.add(RValue::get(EmitCastToVoidPtr(atomics.getAtomicPointer())), 2025 getContext().VoidPtrTy); 2026 args.add(RValue::get(EmitCastToVoidPtr(srcAddr.getPointer())), 2027 getContext().VoidPtrTy); 2028 args.add( 2029 RValue::get(llvm::ConstantInt::get(IntTy, (int)llvm::toCABI(AO))), 2030 getContext().IntTy); 2031 emitAtomicLibcall(*this, "__atomic_store", getContext().VoidTy, args); 2032 return; 2033 } 2034 2035 // Okay, we're doing this natively. 2036 llvm::Value *intValue = atomics.convertRValueToInt(rvalue); 2037 2038 // Do the atomic store. 2039 Address addr = 2040 atomics.emitCastToAtomicIntPointer(atomics.getAtomicAddress()); 2041 intValue = Builder.CreateIntCast( 2042 intValue, addr.getElementType(), /*isSigned=*/false); 2043 llvm::StoreInst *store = Builder.CreateStore(intValue, addr); 2044 2045 if (AO == llvm::AtomicOrdering::Acquire) 2046 AO = llvm::AtomicOrdering::Monotonic; 2047 else if (AO == llvm::AtomicOrdering::AcquireRelease) 2048 AO = llvm::AtomicOrdering::Release; 2049 // Initializations don't need to be atomic. 2050 if (!isInit) 2051 store->setAtomic(AO); 2052 2053 // Other decoration. 2054 if (IsVolatile) 2055 store->setVolatile(true); 2056 CGM.DecorateInstructionWithTBAA(store, dest.getTBAAInfo()); 2057 return; 2058 } 2059 2060 // Emit simple atomic update operation. 2061 atomics.EmitAtomicUpdate(AO, rvalue, IsVolatile); 2062 } 2063 2064 /// Emit a compare-and-exchange op for atomic type. 2065 /// 2066 std::pair<RValue, llvm::Value *> CodeGenFunction::EmitAtomicCompareExchange( 2067 LValue Obj, RValue Expected, RValue Desired, SourceLocation Loc, 2068 llvm::AtomicOrdering Success, llvm::AtomicOrdering Failure, bool IsWeak, 2069 AggValueSlot Slot) { 2070 // If this is an aggregate r-value, it should agree in type except 2071 // maybe for address-space qualification. 2072 assert(!Expected.isAggregate() || 2073 Expected.getAggregateAddress().getElementType() == 2074 Obj.getAddress(*this).getElementType()); 2075 assert(!Desired.isAggregate() || 2076 Desired.getAggregateAddress().getElementType() == 2077 Obj.getAddress(*this).getElementType()); 2078 AtomicInfo Atomics(*this, Obj); 2079 2080 return Atomics.EmitAtomicCompareExchange(Expected, Desired, Success, Failure, 2081 IsWeak); 2082 } 2083 2084 void CodeGenFunction::EmitAtomicUpdate( 2085 LValue LVal, llvm::AtomicOrdering AO, 2086 const llvm::function_ref<RValue(RValue)> &UpdateOp, bool IsVolatile) { 2087 AtomicInfo Atomics(*this, LVal); 2088 Atomics.EmitAtomicUpdate(AO, UpdateOp, IsVolatile); 2089 } 2090 2091 void CodeGenFunction::EmitAtomicInit(Expr *init, LValue dest) { 2092 AtomicInfo atomics(*this, dest); 2093 2094 switch (atomics.getEvaluationKind()) { 2095 case TEK_Scalar: { 2096 llvm::Value *value = EmitScalarExpr(init); 2097 atomics.emitCopyIntoMemory(RValue::get(value)); 2098 return; 2099 } 2100 2101 case TEK_Complex: { 2102 ComplexPairTy value = EmitComplexExpr(init); 2103 atomics.emitCopyIntoMemory(RValue::getComplex(value)); 2104 return; 2105 } 2106 2107 case TEK_Aggregate: { 2108 // Fix up the destination if the initializer isn't an expression 2109 // of atomic type. 2110 bool Zeroed = false; 2111 if (!init->getType()->isAtomicType()) { 2112 Zeroed = atomics.emitMemSetZeroIfNecessary(); 2113 dest = atomics.projectValue(); 2114 } 2115 2116 // Evaluate the expression directly into the destination. 2117 AggValueSlot slot = AggValueSlot::forLValue( 2118 dest, *this, AggValueSlot::IsNotDestructed, 2119 AggValueSlot::DoesNotNeedGCBarriers, AggValueSlot::IsNotAliased, 2120 AggValueSlot::DoesNotOverlap, 2121 Zeroed ? AggValueSlot::IsZeroed : AggValueSlot::IsNotZeroed); 2122 2123 EmitAggExpr(init, slot); 2124 return; 2125 } 2126 } 2127 llvm_unreachable("bad evaluation kind"); 2128 } 2129