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__hip_atomic_compare_exchange_strong:
528   case AtomicExpr::AO__opencl_atomic_compare_exchange_strong:
529     emitAtomicCmpXchgFailureSet(CGF, E, false, Dest, Ptr, Val1, Val2,
530                                 FailureOrder, Size, Order, Scope);
531     return;
532   case AtomicExpr::AO__c11_atomic_compare_exchange_weak:
533   case AtomicExpr::AO__opencl_atomic_compare_exchange_weak:
534   case AtomicExpr::AO__hip_atomic_compare_exchange_weak:
535     emitAtomicCmpXchgFailureSet(CGF, E, true, Dest, Ptr, Val1, Val2,
536                                 FailureOrder, Size, Order, Scope);
537     return;
538   case AtomicExpr::AO__atomic_compare_exchange:
539   case AtomicExpr::AO__atomic_compare_exchange_n: {
540     if (llvm::ConstantInt *IsWeakC = dyn_cast<llvm::ConstantInt>(IsWeak)) {
541       emitAtomicCmpXchgFailureSet(CGF, E, IsWeakC->getZExtValue(), Dest, Ptr,
542                                   Val1, Val2, FailureOrder, Size, Order, Scope);
543     } else {
544       // Create all the relevant BB's
545       llvm::BasicBlock *StrongBB =
546           CGF.createBasicBlock("cmpxchg.strong", CGF.CurFn);
547       llvm::BasicBlock *WeakBB = CGF.createBasicBlock("cmxchg.weak", CGF.CurFn);
548       llvm::BasicBlock *ContBB =
549           CGF.createBasicBlock("cmpxchg.continue", CGF.CurFn);
550 
551       llvm::SwitchInst *SI = CGF.Builder.CreateSwitch(IsWeak, WeakBB);
552       SI->addCase(CGF.Builder.getInt1(false), StrongBB);
553 
554       CGF.Builder.SetInsertPoint(StrongBB);
555       emitAtomicCmpXchgFailureSet(CGF, E, false, Dest, Ptr, Val1, Val2,
556                                   FailureOrder, Size, Order, Scope);
557       CGF.Builder.CreateBr(ContBB);
558 
559       CGF.Builder.SetInsertPoint(WeakBB);
560       emitAtomicCmpXchgFailureSet(CGF, E, true, Dest, Ptr, Val1, Val2,
561                                   FailureOrder, Size, Order, Scope);
562       CGF.Builder.CreateBr(ContBB);
563 
564       CGF.Builder.SetInsertPoint(ContBB);
565     }
566     return;
567   }
568   case AtomicExpr::AO__c11_atomic_load:
569   case AtomicExpr::AO__opencl_atomic_load:
570   case AtomicExpr::AO__hip_atomic_load:
571   case AtomicExpr::AO__atomic_load_n:
572   case AtomicExpr::AO__atomic_load: {
573     llvm::LoadInst *Load = CGF.Builder.CreateLoad(Ptr);
574     Load->setAtomic(Order, Scope);
575     Load->setVolatile(E->isVolatile());
576     CGF.Builder.CreateStore(Load, Dest);
577     return;
578   }
579 
580   case AtomicExpr::AO__c11_atomic_store:
581   case AtomicExpr::AO__opencl_atomic_store:
582   case AtomicExpr::AO__hip_atomic_store:
583   case AtomicExpr::AO__atomic_store:
584   case AtomicExpr::AO__atomic_store_n: {
585     llvm::Value *LoadVal1 = CGF.Builder.CreateLoad(Val1);
586     llvm::StoreInst *Store = CGF.Builder.CreateStore(LoadVal1, Ptr);
587     Store->setAtomic(Order, Scope);
588     Store->setVolatile(E->isVolatile());
589     return;
590   }
591 
592   case AtomicExpr::AO__c11_atomic_exchange:
593   case AtomicExpr::AO__hip_atomic_exchange:
594   case AtomicExpr::AO__opencl_atomic_exchange:
595   case AtomicExpr::AO__atomic_exchange_n:
596   case AtomicExpr::AO__atomic_exchange:
597     Op = llvm::AtomicRMWInst::Xchg;
598     break;
599 
600   case AtomicExpr::AO__atomic_add_fetch:
601     PostOp = E->getValueType()->isFloatingType() ? llvm::Instruction::FAdd
602                                                  : llvm::Instruction::Add;
603     LLVM_FALLTHROUGH;
604   case AtomicExpr::AO__c11_atomic_fetch_add:
605   case AtomicExpr::AO__hip_atomic_fetch_add:
606   case AtomicExpr::AO__opencl_atomic_fetch_add:
607   case AtomicExpr::AO__atomic_fetch_add:
608     Op = E->getValueType()->isFloatingType() ? llvm::AtomicRMWInst::FAdd
609                                              : llvm::AtomicRMWInst::Add;
610     break;
611 
612   case AtomicExpr::AO__atomic_sub_fetch:
613     PostOp = E->getValueType()->isFloatingType() ? llvm::Instruction::FSub
614                                                  : 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 = E->getValueType()->isFloatingType() ? llvm::AtomicRMWInst::FSub
620                                              : llvm::AtomicRMWInst::Sub;
621     break;
622 
623   case AtomicExpr::AO__atomic_min_fetch:
624     PostOpMinMax = true;
625     LLVM_FALLTHROUGH;
626   case AtomicExpr::AO__c11_atomic_fetch_min:
627   case AtomicExpr::AO__hip_atomic_fetch_min:
628   case AtomicExpr::AO__opencl_atomic_fetch_min:
629   case AtomicExpr::AO__atomic_fetch_min:
630     Op = E->getValueType()->isSignedIntegerType() ? llvm::AtomicRMWInst::Min
631                                                   : llvm::AtomicRMWInst::UMin;
632     break;
633 
634   case AtomicExpr::AO__atomic_max_fetch:
635     PostOpMinMax = true;
636     LLVM_FALLTHROUGH;
637   case AtomicExpr::AO__c11_atomic_fetch_max:
638   case AtomicExpr::AO__hip_atomic_fetch_max:
639   case AtomicExpr::AO__opencl_atomic_fetch_max:
640   case AtomicExpr::AO__atomic_fetch_max:
641     Op = E->getValueType()->isSignedIntegerType() ? llvm::AtomicRMWInst::Max
642                                                   : llvm::AtomicRMWInst::UMax;
643     break;
644 
645   case AtomicExpr::AO__atomic_and_fetch:
646     PostOp = llvm::Instruction::And;
647     LLVM_FALLTHROUGH;
648   case AtomicExpr::AO__c11_atomic_fetch_and:
649   case AtomicExpr::AO__hip_atomic_fetch_and:
650   case AtomicExpr::AO__opencl_atomic_fetch_and:
651   case AtomicExpr::AO__atomic_fetch_and:
652     Op = llvm::AtomicRMWInst::And;
653     break;
654 
655   case AtomicExpr::AO__atomic_or_fetch:
656     PostOp = llvm::Instruction::Or;
657     LLVM_FALLTHROUGH;
658   case AtomicExpr::AO__c11_atomic_fetch_or:
659   case AtomicExpr::AO__hip_atomic_fetch_or:
660   case AtomicExpr::AO__opencl_atomic_fetch_or:
661   case AtomicExpr::AO__atomic_fetch_or:
662     Op = llvm::AtomicRMWInst::Or;
663     break;
664 
665   case AtomicExpr::AO__atomic_xor_fetch:
666     PostOp = llvm::Instruction::Xor;
667     LLVM_FALLTHROUGH;
668   case AtomicExpr::AO__c11_atomic_fetch_xor:
669   case AtomicExpr::AO__hip_atomic_fetch_xor:
670   case AtomicExpr::AO__opencl_atomic_fetch_xor:
671   case AtomicExpr::AO__atomic_fetch_xor:
672     Op = llvm::AtomicRMWInst::Xor;
673     break;
674 
675   case AtomicExpr::AO__atomic_nand_fetch:
676     PostOp = llvm::Instruction::And; // the NOT is special cased below
677     LLVM_FALLTHROUGH;
678   case AtomicExpr::AO__c11_atomic_fetch_nand:
679   case AtomicExpr::AO__atomic_fetch_nand:
680     Op = llvm::AtomicRMWInst::Nand;
681     break;
682   }
683 
684   llvm::Value *LoadVal1 = CGF.Builder.CreateLoad(Val1);
685   llvm::AtomicRMWInst *RMWI =
686       CGF.Builder.CreateAtomicRMW(Op, Ptr.getPointer(), LoadVal1, Order, Scope);
687   RMWI->setVolatile(E->isVolatile());
688 
689   // For __atomic_*_fetch operations, perform the operation again to
690   // determine the value which was written.
691   llvm::Value *Result = RMWI;
692   if (PostOpMinMax)
693     Result = EmitPostAtomicMinMax(CGF.Builder, E->getOp(),
694                                   E->getValueType()->isSignedIntegerType(),
695                                   RMWI, LoadVal1);
696   else if (PostOp)
697     Result = CGF.Builder.CreateBinOp((llvm::Instruction::BinaryOps)PostOp, RMWI,
698                                      LoadVal1);
699   if (E->getOp() == AtomicExpr::AO__atomic_nand_fetch)
700     Result = CGF.Builder.CreateNot(Result);
701   CGF.Builder.CreateStore(Result, Dest);
702 }
703 
704 // This function emits any expression (scalar, complex, or aggregate)
705 // into a temporary alloca.
706 static Address
707 EmitValToTemp(CodeGenFunction &CGF, Expr *E) {
708   Address DeclPtr = CGF.CreateMemTemp(E->getType(), ".atomictmp");
709   CGF.EmitAnyExprToMem(E, DeclPtr, E->getType().getQualifiers(),
710                        /*Init*/ true);
711   return DeclPtr;
712 }
713 
714 static void EmitAtomicOp(CodeGenFunction &CGF, AtomicExpr *Expr, Address Dest,
715                          Address Ptr, Address Val1, Address Val2,
716                          llvm::Value *IsWeak, llvm::Value *FailureOrder,
717                          uint64_t Size, llvm::AtomicOrdering Order,
718                          llvm::Value *Scope) {
719   auto ScopeModel = Expr->getScopeModel();
720 
721   // LLVM atomic instructions always have synch scope. If clang atomic
722   // expression has no scope operand, use default LLVM synch scope.
723   if (!ScopeModel) {
724     EmitAtomicOp(CGF, Expr, Dest, Ptr, Val1, Val2, IsWeak, FailureOrder, Size,
725                  Order, CGF.CGM.getLLVMContext().getOrInsertSyncScopeID(""));
726     return;
727   }
728 
729   // Handle constant scope.
730   if (auto SC = dyn_cast<llvm::ConstantInt>(Scope)) {
731     auto SCID = CGF.getTargetHooks().getLLVMSyncScopeID(
732         CGF.CGM.getLangOpts(), ScopeModel->map(SC->getZExtValue()),
733         Order, CGF.CGM.getLLVMContext());
734     EmitAtomicOp(CGF, Expr, Dest, Ptr, Val1, Val2, IsWeak, FailureOrder, Size,
735                  Order, SCID);
736     return;
737   }
738 
739   // Handle non-constant scope.
740   auto &Builder = CGF.Builder;
741   auto Scopes = ScopeModel->getRuntimeValues();
742   llvm::DenseMap<unsigned, llvm::BasicBlock *> BB;
743   for (auto S : Scopes)
744     BB[S] = CGF.createBasicBlock(getAsString(ScopeModel->map(S)), CGF.CurFn);
745 
746   llvm::BasicBlock *ContBB =
747       CGF.createBasicBlock("atomic.scope.continue", CGF.CurFn);
748 
749   auto *SC = Builder.CreateIntCast(Scope, Builder.getInt32Ty(), false);
750   // If unsupported synch scope is encountered at run time, assume a fallback
751   // synch scope value.
752   auto FallBack = ScopeModel->getFallBackValue();
753   llvm::SwitchInst *SI = Builder.CreateSwitch(SC, BB[FallBack]);
754   for (auto S : Scopes) {
755     auto *B = BB[S];
756     if (S != FallBack)
757       SI->addCase(Builder.getInt32(S), B);
758 
759     Builder.SetInsertPoint(B);
760     EmitAtomicOp(CGF, Expr, Dest, Ptr, Val1, Val2, IsWeak, FailureOrder, Size,
761                  Order,
762                  CGF.getTargetHooks().getLLVMSyncScopeID(CGF.CGM.getLangOpts(),
763                                                          ScopeModel->map(S),
764                                                          Order,
765                                                          CGF.getLLVMContext()));
766     Builder.CreateBr(ContBB);
767   }
768 
769   Builder.SetInsertPoint(ContBB);
770 }
771 
772 static void
773 AddDirectArgument(CodeGenFunction &CGF, CallArgList &Args,
774                   bool UseOptimizedLibcall, llvm::Value *Val, QualType ValTy,
775                   SourceLocation Loc, CharUnits SizeInChars) {
776   if (UseOptimizedLibcall) {
777     // Load value and pass it to the function directly.
778     CharUnits Align = CGF.getContext().getTypeAlignInChars(ValTy);
779     int64_t SizeInBits = CGF.getContext().toBits(SizeInChars);
780     ValTy =
781         CGF.getContext().getIntTypeForBitwidth(SizeInBits, /*Signed=*/false);
782     llvm::Type *IPtrTy = llvm::IntegerType::get(CGF.getLLVMContext(),
783                                                 SizeInBits)->getPointerTo();
784     Address Ptr = Address(CGF.Builder.CreateBitCast(Val, IPtrTy), Align);
785     Val = CGF.EmitLoadOfScalar(Ptr, false,
786                                CGF.getContext().getPointerType(ValTy),
787                                Loc);
788     // Coerce the value into an appropriately sized integer type.
789     Args.add(RValue::get(Val), ValTy);
790   } else {
791     // Non-optimized functions always take a reference.
792     Args.add(RValue::get(CGF.EmitCastToVoidPtr(Val)),
793                          CGF.getContext().VoidPtrTy);
794   }
795 }
796 
797 RValue CodeGenFunction::EmitAtomicExpr(AtomicExpr *E) {
798   QualType AtomicTy = E->getPtr()->getType()->getPointeeType();
799   QualType MemTy = AtomicTy;
800   if (const AtomicType *AT = AtomicTy->getAs<AtomicType>())
801     MemTy = AT->getValueType();
802   llvm::Value *IsWeak = nullptr, *OrderFail = nullptr;
803 
804   Address Val1 = Address::invalid();
805   Address Val2 = Address::invalid();
806   Address Dest = Address::invalid();
807   Address Ptr = EmitPointerWithAlignment(E->getPtr());
808 
809   if (E->getOp() == AtomicExpr::AO__c11_atomic_init ||
810       E->getOp() == AtomicExpr::AO__opencl_atomic_init) {
811     LValue lvalue = MakeAddrLValue(Ptr, AtomicTy);
812     EmitAtomicInit(E->getVal1(), lvalue);
813     return RValue::get(nullptr);
814   }
815 
816   auto TInfo = getContext().getTypeInfoInChars(AtomicTy);
817   uint64_t Size = TInfo.Width.getQuantity();
818   unsigned MaxInlineWidthInBits = getTarget().getMaxAtomicInlineWidth();
819 
820   bool Oversized = getContext().toBits(TInfo.Width) > MaxInlineWidthInBits;
821   bool Misaligned = (Ptr.getAlignment() % TInfo.Width) != 0;
822   bool UseLibcall = Misaligned | Oversized;
823   bool ShouldCastToIntPtrTy = true;
824 
825   CharUnits MaxInlineWidth =
826       getContext().toCharUnitsFromBits(MaxInlineWidthInBits);
827 
828   DiagnosticsEngine &Diags = CGM.getDiags();
829 
830   if (Misaligned) {
831     Diags.Report(E->getBeginLoc(), diag::warn_atomic_op_misaligned)
832         << (int)TInfo.Width.getQuantity()
833         << (int)Ptr.getAlignment().getQuantity();
834   }
835 
836   if (Oversized) {
837     Diags.Report(E->getBeginLoc(), diag::warn_atomic_op_oversized)
838         << (int)TInfo.Width.getQuantity() << (int)MaxInlineWidth.getQuantity();
839   }
840 
841   llvm::Value *Order = EmitScalarExpr(E->getOrder());
842   llvm::Value *Scope =
843       E->getScopeModel() ? EmitScalarExpr(E->getScope()) : nullptr;
844 
845   switch (E->getOp()) {
846   case AtomicExpr::AO__c11_atomic_init:
847   case AtomicExpr::AO__opencl_atomic_init:
848     llvm_unreachable("Already handled above with EmitAtomicInit!");
849 
850   case AtomicExpr::AO__c11_atomic_load:
851   case AtomicExpr::AO__opencl_atomic_load:
852   case AtomicExpr::AO__hip_atomic_load:
853   case AtomicExpr::AO__atomic_load_n:
854     break;
855 
856   case AtomicExpr::AO__atomic_load:
857     Dest = EmitPointerWithAlignment(E->getVal1());
858     break;
859 
860   case AtomicExpr::AO__atomic_store:
861     Val1 = EmitPointerWithAlignment(E->getVal1());
862     break;
863 
864   case AtomicExpr::AO__atomic_exchange:
865     Val1 = EmitPointerWithAlignment(E->getVal1());
866     Dest = EmitPointerWithAlignment(E->getVal2());
867     break;
868 
869   case AtomicExpr::AO__c11_atomic_compare_exchange_strong:
870   case AtomicExpr::AO__c11_atomic_compare_exchange_weak:
871   case AtomicExpr::AO__opencl_atomic_compare_exchange_strong:
872   case AtomicExpr::AO__hip_atomic_compare_exchange_strong:
873   case AtomicExpr::AO__opencl_atomic_compare_exchange_weak:
874   case AtomicExpr::AO__hip_atomic_compare_exchange_weak:
875   case AtomicExpr::AO__atomic_compare_exchange_n:
876   case AtomicExpr::AO__atomic_compare_exchange:
877     Val1 = EmitPointerWithAlignment(E->getVal1());
878     if (E->getOp() == AtomicExpr::AO__atomic_compare_exchange)
879       Val2 = EmitPointerWithAlignment(E->getVal2());
880     else
881       Val2 = EmitValToTemp(*this, E->getVal2());
882     OrderFail = EmitScalarExpr(E->getOrderFail());
883     if (E->getOp() == AtomicExpr::AO__atomic_compare_exchange_n ||
884         E->getOp() == AtomicExpr::AO__atomic_compare_exchange)
885       IsWeak = EmitScalarExpr(E->getWeak());
886     break;
887 
888   case AtomicExpr::AO__c11_atomic_fetch_add:
889   case AtomicExpr::AO__c11_atomic_fetch_sub:
890   case AtomicExpr::AO__hip_atomic_fetch_add:
891   case AtomicExpr::AO__opencl_atomic_fetch_add:
892   case AtomicExpr::AO__opencl_atomic_fetch_sub:
893     if (MemTy->isPointerType()) {
894       // For pointer arithmetic, we're required to do a bit of math:
895       // adding 1 to an int* is not the same as adding 1 to a uintptr_t.
896       // ... but only for the C11 builtins. The GNU builtins expect the
897       // user to multiply by sizeof(T).
898       QualType Val1Ty = E->getVal1()->getType();
899       llvm::Value *Val1Scalar = EmitScalarExpr(E->getVal1());
900       CharUnits PointeeIncAmt =
901           getContext().getTypeSizeInChars(MemTy->getPointeeType());
902       Val1Scalar = Builder.CreateMul(Val1Scalar, CGM.getSize(PointeeIncAmt));
903       auto Temp = CreateMemTemp(Val1Ty, ".atomictmp");
904       Val1 = Temp;
905       EmitStoreOfScalar(Val1Scalar, MakeAddrLValue(Temp, Val1Ty));
906       break;
907     }
908     LLVM_FALLTHROUGH;
909   case AtomicExpr::AO__atomic_fetch_add:
910   case AtomicExpr::AO__atomic_fetch_sub:
911   case AtomicExpr::AO__atomic_add_fetch:
912   case AtomicExpr::AO__atomic_sub_fetch:
913     ShouldCastToIntPtrTy = !MemTy->isFloatingType();
914     LLVM_FALLTHROUGH;
915 
916   case AtomicExpr::AO__c11_atomic_store:
917   case AtomicExpr::AO__c11_atomic_exchange:
918   case AtomicExpr::AO__opencl_atomic_store:
919   case AtomicExpr::AO__hip_atomic_store:
920   case AtomicExpr::AO__opencl_atomic_exchange:
921   case AtomicExpr::AO__hip_atomic_exchange:
922   case AtomicExpr::AO__atomic_store_n:
923   case AtomicExpr::AO__atomic_exchange_n:
924   case AtomicExpr::AO__c11_atomic_fetch_and:
925   case AtomicExpr::AO__c11_atomic_fetch_or:
926   case AtomicExpr::AO__c11_atomic_fetch_xor:
927   case AtomicExpr::AO__c11_atomic_fetch_nand:
928   case AtomicExpr::AO__c11_atomic_fetch_max:
929   case AtomicExpr::AO__c11_atomic_fetch_min:
930   case AtomicExpr::AO__opencl_atomic_fetch_and:
931   case AtomicExpr::AO__opencl_atomic_fetch_or:
932   case AtomicExpr::AO__opencl_atomic_fetch_xor:
933   case AtomicExpr::AO__opencl_atomic_fetch_min:
934   case AtomicExpr::AO__opencl_atomic_fetch_max:
935   case AtomicExpr::AO__atomic_fetch_and:
936   case AtomicExpr::AO__hip_atomic_fetch_and:
937   case AtomicExpr::AO__atomic_fetch_or:
938   case AtomicExpr::AO__hip_atomic_fetch_or:
939   case AtomicExpr::AO__atomic_fetch_xor:
940   case AtomicExpr::AO__hip_atomic_fetch_xor:
941   case AtomicExpr::AO__atomic_fetch_nand:
942   case AtomicExpr::AO__atomic_and_fetch:
943   case AtomicExpr::AO__atomic_or_fetch:
944   case AtomicExpr::AO__atomic_xor_fetch:
945   case AtomicExpr::AO__atomic_nand_fetch:
946   case AtomicExpr::AO__atomic_max_fetch:
947   case AtomicExpr::AO__atomic_min_fetch:
948   case AtomicExpr::AO__atomic_fetch_max:
949   case AtomicExpr::AO__hip_atomic_fetch_max:
950   case AtomicExpr::AO__atomic_fetch_min:
951   case AtomicExpr::AO__hip_atomic_fetch_min:
952     Val1 = EmitValToTemp(*this, E->getVal1());
953     break;
954   }
955 
956   QualType RValTy = E->getType().getUnqualifiedType();
957 
958   // The inlined atomics only function on iN types, where N is a power of 2. We
959   // need to make sure (via temporaries if necessary) that all incoming values
960   // are compatible.
961   LValue AtomicVal = MakeAddrLValue(Ptr, AtomicTy);
962   AtomicInfo Atomics(*this, AtomicVal);
963 
964   if (ShouldCastToIntPtrTy) {
965     Ptr = Atomics.emitCastToAtomicIntPointer(Ptr);
966     if (Val1.isValid())
967       Val1 = Atomics.convertToAtomicIntPointer(Val1);
968     if (Val2.isValid())
969       Val2 = Atomics.convertToAtomicIntPointer(Val2);
970   }
971   if (Dest.isValid()) {
972     if (ShouldCastToIntPtrTy)
973       Dest = Atomics.emitCastToAtomicIntPointer(Dest);
974   } else if (E->isCmpXChg())
975     Dest = CreateMemTemp(RValTy, "cmpxchg.bool");
976   else if (!RValTy->isVoidType()) {
977     Dest = Atomics.CreateTempAlloca();
978     if (ShouldCastToIntPtrTy)
979       Dest = Atomics.emitCastToAtomicIntPointer(Dest);
980   }
981 
982   // Use a library call.  See: http://gcc.gnu.org/wiki/Atomic/GCCMM/LIbrary .
983   if (UseLibcall) {
984     bool UseOptimizedLibcall = false;
985     switch (E->getOp()) {
986     case AtomicExpr::AO__c11_atomic_init:
987     case AtomicExpr::AO__opencl_atomic_init:
988       llvm_unreachable("Already handled above with EmitAtomicInit!");
989 
990     case AtomicExpr::AO__c11_atomic_fetch_add:
991     case AtomicExpr::AO__opencl_atomic_fetch_add:
992     case AtomicExpr::AO__atomic_fetch_add:
993     case AtomicExpr::AO__hip_atomic_fetch_add:
994     case AtomicExpr::AO__c11_atomic_fetch_and:
995     case AtomicExpr::AO__opencl_atomic_fetch_and:
996     case AtomicExpr::AO__hip_atomic_fetch_and:
997     case AtomicExpr::AO__atomic_fetch_and:
998     case AtomicExpr::AO__c11_atomic_fetch_or:
999     case AtomicExpr::AO__opencl_atomic_fetch_or:
1000     case AtomicExpr::AO__hip_atomic_fetch_or:
1001     case AtomicExpr::AO__atomic_fetch_or:
1002     case AtomicExpr::AO__c11_atomic_fetch_nand:
1003     case AtomicExpr::AO__atomic_fetch_nand:
1004     case AtomicExpr::AO__c11_atomic_fetch_sub:
1005     case AtomicExpr::AO__opencl_atomic_fetch_sub:
1006     case AtomicExpr::AO__atomic_fetch_sub:
1007     case AtomicExpr::AO__c11_atomic_fetch_xor:
1008     case AtomicExpr::AO__opencl_atomic_fetch_xor:
1009     case AtomicExpr::AO__opencl_atomic_fetch_min:
1010     case AtomicExpr::AO__opencl_atomic_fetch_max:
1011     case AtomicExpr::AO__atomic_fetch_xor:
1012     case AtomicExpr::AO__hip_atomic_fetch_xor:
1013     case AtomicExpr::AO__c11_atomic_fetch_max:
1014     case AtomicExpr::AO__c11_atomic_fetch_min:
1015     case AtomicExpr::AO__atomic_add_fetch:
1016     case AtomicExpr::AO__atomic_and_fetch:
1017     case AtomicExpr::AO__atomic_nand_fetch:
1018     case AtomicExpr::AO__atomic_or_fetch:
1019     case AtomicExpr::AO__atomic_sub_fetch:
1020     case AtomicExpr::AO__atomic_xor_fetch:
1021     case AtomicExpr::AO__atomic_fetch_max:
1022     case AtomicExpr::AO__hip_atomic_fetch_max:
1023     case AtomicExpr::AO__atomic_fetch_min:
1024     case AtomicExpr::AO__hip_atomic_fetch_min:
1025     case AtomicExpr::AO__atomic_max_fetch:
1026     case AtomicExpr::AO__atomic_min_fetch:
1027       // For these, only library calls for certain sizes exist.
1028       UseOptimizedLibcall = true;
1029       break;
1030 
1031     case AtomicExpr::AO__atomic_load:
1032     case AtomicExpr::AO__atomic_store:
1033     case AtomicExpr::AO__atomic_exchange:
1034     case AtomicExpr::AO__atomic_compare_exchange:
1035       // Use the generic version if we don't know that the operand will be
1036       // suitably aligned for the optimized version.
1037       if (Misaligned)
1038         break;
1039       LLVM_FALLTHROUGH;
1040     case AtomicExpr::AO__c11_atomic_load:
1041     case AtomicExpr::AO__c11_atomic_store:
1042     case AtomicExpr::AO__c11_atomic_exchange:
1043     case AtomicExpr::AO__c11_atomic_compare_exchange_weak:
1044     case AtomicExpr::AO__c11_atomic_compare_exchange_strong:
1045     case AtomicExpr::AO__hip_atomic_compare_exchange_strong:
1046     case AtomicExpr::AO__opencl_atomic_load:
1047     case AtomicExpr::AO__hip_atomic_load:
1048     case AtomicExpr::AO__opencl_atomic_store:
1049     case AtomicExpr::AO__hip_atomic_store:
1050     case AtomicExpr::AO__opencl_atomic_exchange:
1051     case AtomicExpr::AO__hip_atomic_exchange:
1052     case AtomicExpr::AO__opencl_atomic_compare_exchange_weak:
1053     case AtomicExpr::AO__hip_atomic_compare_exchange_weak:
1054     case AtomicExpr::AO__opencl_atomic_compare_exchange_strong:
1055     case AtomicExpr::AO__atomic_load_n:
1056     case AtomicExpr::AO__atomic_store_n:
1057     case AtomicExpr::AO__atomic_exchange_n:
1058     case AtomicExpr::AO__atomic_compare_exchange_n:
1059       // Only use optimized library calls for sizes for which they exist.
1060       // FIXME: Size == 16 optimized library functions exist too.
1061       if (Size == 1 || Size == 2 || Size == 4 || Size == 8)
1062         UseOptimizedLibcall = true;
1063       break;
1064     }
1065 
1066     CallArgList Args;
1067     if (!UseOptimizedLibcall) {
1068       // For non-optimized library calls, the size is the first parameter
1069       Args.add(RValue::get(llvm::ConstantInt::get(SizeTy, Size)),
1070                getContext().getSizeType());
1071     }
1072     // Atomic address is the first or second parameter
1073     // The OpenCL atomic library functions only accept pointer arguments to
1074     // generic address space.
1075     auto CastToGenericAddrSpace = [&](llvm::Value *V, QualType PT) {
1076       if (!E->isOpenCL())
1077         return V;
1078       auto AS = PT->castAs<PointerType>()->getPointeeType().getAddressSpace();
1079       if (AS == LangAS::opencl_generic)
1080         return V;
1081       auto DestAS = getContext().getTargetAddressSpace(LangAS::opencl_generic);
1082       auto T = V->getType();
1083       auto *DestType = T->getPointerElementType()->getPointerTo(DestAS);
1084 
1085       return getTargetHooks().performAddrSpaceCast(
1086           *this, V, AS, LangAS::opencl_generic, DestType, false);
1087     };
1088 
1089     Args.add(RValue::get(CastToGenericAddrSpace(
1090                  EmitCastToVoidPtr(Ptr.getPointer()), E->getPtr()->getType())),
1091              getContext().VoidPtrTy);
1092 
1093     std::string LibCallName;
1094     QualType LoweredMemTy =
1095       MemTy->isPointerType() ? getContext().getIntPtrType() : MemTy;
1096     QualType RetTy;
1097     bool HaveRetTy = false;
1098     llvm::Instruction::BinaryOps PostOp = (llvm::Instruction::BinaryOps)0;
1099     bool PostOpMinMax = false;
1100     switch (E->getOp()) {
1101     case AtomicExpr::AO__c11_atomic_init:
1102     case AtomicExpr::AO__opencl_atomic_init:
1103       llvm_unreachable("Already handled!");
1104 
1105     // There is only one libcall for compare an exchange, because there is no
1106     // optimisation benefit possible from a libcall version of a weak compare
1107     // and exchange.
1108     // bool __atomic_compare_exchange(size_t size, void *mem, void *expected,
1109     //                                void *desired, int success, int failure)
1110     // bool __atomic_compare_exchange_N(T *mem, T *expected, T desired,
1111     //                                  int success, int failure)
1112     case AtomicExpr::AO__c11_atomic_compare_exchange_weak:
1113     case AtomicExpr::AO__c11_atomic_compare_exchange_strong:
1114     case AtomicExpr::AO__opencl_atomic_compare_exchange_weak:
1115     case AtomicExpr::AO__hip_atomic_compare_exchange_weak:
1116     case AtomicExpr::AO__opencl_atomic_compare_exchange_strong:
1117     case AtomicExpr::AO__hip_atomic_compare_exchange_strong:
1118     case AtomicExpr::AO__atomic_compare_exchange:
1119     case AtomicExpr::AO__atomic_compare_exchange_n:
1120       LibCallName = "__atomic_compare_exchange";
1121       RetTy = getContext().BoolTy;
1122       HaveRetTy = true;
1123       Args.add(
1124           RValue::get(CastToGenericAddrSpace(
1125               EmitCastToVoidPtr(Val1.getPointer()), E->getVal1()->getType())),
1126           getContext().VoidPtrTy);
1127       AddDirectArgument(*this, Args, UseOptimizedLibcall, Val2.getPointer(),
1128                         MemTy, E->getExprLoc(), TInfo.Width);
1129       Args.add(RValue::get(Order), getContext().IntTy);
1130       Order = OrderFail;
1131       break;
1132     // void __atomic_exchange(size_t size, void *mem, void *val, void *return,
1133     //                        int order)
1134     // T __atomic_exchange_N(T *mem, T val, int order)
1135     case AtomicExpr::AO__c11_atomic_exchange:
1136     case AtomicExpr::AO__opencl_atomic_exchange:
1137     case AtomicExpr::AO__atomic_exchange_n:
1138     case AtomicExpr::AO__atomic_exchange:
1139     case AtomicExpr::AO__hip_atomic_exchange:
1140       LibCallName = "__atomic_exchange";
1141       AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(),
1142                         MemTy, E->getExprLoc(), TInfo.Width);
1143       break;
1144     // void __atomic_store(size_t size, void *mem, void *val, int order)
1145     // void __atomic_store_N(T *mem, T val, int order)
1146     case AtomicExpr::AO__c11_atomic_store:
1147     case AtomicExpr::AO__opencl_atomic_store:
1148     case AtomicExpr::AO__hip_atomic_store:
1149     case AtomicExpr::AO__atomic_store:
1150     case AtomicExpr::AO__atomic_store_n:
1151       LibCallName = "__atomic_store";
1152       RetTy = getContext().VoidTy;
1153       HaveRetTy = true;
1154       AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(),
1155                         MemTy, E->getExprLoc(), TInfo.Width);
1156       break;
1157     // void __atomic_load(size_t size, void *mem, void *return, int order)
1158     // T __atomic_load_N(T *mem, int order)
1159     case AtomicExpr::AO__c11_atomic_load:
1160     case AtomicExpr::AO__opencl_atomic_load:
1161     case AtomicExpr::AO__hip_atomic_load:
1162     case AtomicExpr::AO__atomic_load:
1163     case AtomicExpr::AO__atomic_load_n:
1164       LibCallName = "__atomic_load";
1165       break;
1166     // T __atomic_add_fetch_N(T *mem, T val, int order)
1167     // T __atomic_fetch_add_N(T *mem, T val, int order)
1168     case AtomicExpr::AO__atomic_add_fetch:
1169       PostOp = llvm::Instruction::Add;
1170       LLVM_FALLTHROUGH;
1171     case AtomicExpr::AO__c11_atomic_fetch_add:
1172     case AtomicExpr::AO__opencl_atomic_fetch_add:
1173     case AtomicExpr::AO__atomic_fetch_add:
1174     case AtomicExpr::AO__hip_atomic_fetch_add:
1175       LibCallName = "__atomic_fetch_add";
1176       AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(),
1177                         LoweredMemTy, E->getExprLoc(), TInfo.Width);
1178       break;
1179     // T __atomic_and_fetch_N(T *mem, T val, int order)
1180     // T __atomic_fetch_and_N(T *mem, T val, int order)
1181     case AtomicExpr::AO__atomic_and_fetch:
1182       PostOp = llvm::Instruction::And;
1183       LLVM_FALLTHROUGH;
1184     case AtomicExpr::AO__c11_atomic_fetch_and:
1185     case AtomicExpr::AO__opencl_atomic_fetch_and:
1186     case AtomicExpr::AO__hip_atomic_fetch_and:
1187     case AtomicExpr::AO__atomic_fetch_and:
1188       LibCallName = "__atomic_fetch_and";
1189       AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(),
1190                         MemTy, E->getExprLoc(), TInfo.Width);
1191       break;
1192     // T __atomic_or_fetch_N(T *mem, T val, int order)
1193     // T __atomic_fetch_or_N(T *mem, T val, int order)
1194     case AtomicExpr::AO__atomic_or_fetch:
1195       PostOp = llvm::Instruction::Or;
1196       LLVM_FALLTHROUGH;
1197     case AtomicExpr::AO__c11_atomic_fetch_or:
1198     case AtomicExpr::AO__opencl_atomic_fetch_or:
1199     case AtomicExpr::AO__hip_atomic_fetch_or:
1200     case AtomicExpr::AO__atomic_fetch_or:
1201       LibCallName = "__atomic_fetch_or";
1202       AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(),
1203                         MemTy, E->getExprLoc(), TInfo.Width);
1204       break;
1205     // T __atomic_sub_fetch_N(T *mem, T val, int order)
1206     // T __atomic_fetch_sub_N(T *mem, T val, int order)
1207     case AtomicExpr::AO__atomic_sub_fetch:
1208       PostOp = llvm::Instruction::Sub;
1209       LLVM_FALLTHROUGH;
1210     case AtomicExpr::AO__c11_atomic_fetch_sub:
1211     case AtomicExpr::AO__opencl_atomic_fetch_sub:
1212     case AtomicExpr::AO__atomic_fetch_sub:
1213       LibCallName = "__atomic_fetch_sub";
1214       AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(),
1215                         LoweredMemTy, E->getExprLoc(), TInfo.Width);
1216       break;
1217     // T __atomic_xor_fetch_N(T *mem, T val, int order)
1218     // T __atomic_fetch_xor_N(T *mem, T val, int order)
1219     case AtomicExpr::AO__atomic_xor_fetch:
1220       PostOp = llvm::Instruction::Xor;
1221       LLVM_FALLTHROUGH;
1222     case AtomicExpr::AO__c11_atomic_fetch_xor:
1223     case AtomicExpr::AO__opencl_atomic_fetch_xor:
1224     case AtomicExpr::AO__hip_atomic_fetch_xor:
1225     case AtomicExpr::AO__atomic_fetch_xor:
1226       LibCallName = "__atomic_fetch_xor";
1227       AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(),
1228                         MemTy, E->getExprLoc(), TInfo.Width);
1229       break;
1230     case AtomicExpr::AO__atomic_min_fetch:
1231       PostOpMinMax = true;
1232       LLVM_FALLTHROUGH;
1233     case AtomicExpr::AO__c11_atomic_fetch_min:
1234     case AtomicExpr::AO__atomic_fetch_min:
1235     case AtomicExpr::AO__hip_atomic_fetch_min:
1236     case AtomicExpr::AO__opencl_atomic_fetch_min:
1237       LibCallName = E->getValueType()->isSignedIntegerType()
1238                         ? "__atomic_fetch_min"
1239                         : "__atomic_fetch_umin";
1240       AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(),
1241                         LoweredMemTy, E->getExprLoc(), TInfo.Width);
1242       break;
1243     case AtomicExpr::AO__atomic_max_fetch:
1244       PostOpMinMax = true;
1245       LLVM_FALLTHROUGH;
1246     case AtomicExpr::AO__c11_atomic_fetch_max:
1247     case AtomicExpr::AO__atomic_fetch_max:
1248     case AtomicExpr::AO__hip_atomic_fetch_max:
1249     case AtomicExpr::AO__opencl_atomic_fetch_max:
1250       LibCallName = E->getValueType()->isSignedIntegerType()
1251                         ? "__atomic_fetch_max"
1252                         : "__atomic_fetch_umax";
1253       AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(),
1254                         LoweredMemTy, E->getExprLoc(), TInfo.Width);
1255       break;
1256     // T __atomic_nand_fetch_N(T *mem, T val, int order)
1257     // T __atomic_fetch_nand_N(T *mem, T val, int order)
1258     case AtomicExpr::AO__atomic_nand_fetch:
1259       PostOp = llvm::Instruction::And; // the NOT is special cased below
1260       LLVM_FALLTHROUGH;
1261     case AtomicExpr::AO__c11_atomic_fetch_nand:
1262     case AtomicExpr::AO__atomic_fetch_nand:
1263       LibCallName = "__atomic_fetch_nand";
1264       AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(),
1265                         MemTy, E->getExprLoc(), TInfo.Width);
1266       break;
1267     }
1268 
1269     if (E->isOpenCL()) {
1270       LibCallName = std::string("__opencl") +
1271           StringRef(LibCallName).drop_front(1).str();
1272 
1273     }
1274     // Optimized functions have the size in their name.
1275     if (UseOptimizedLibcall)
1276       LibCallName += "_" + llvm::utostr(Size);
1277     // By default, assume we return a value of the atomic type.
1278     if (!HaveRetTy) {
1279       if (UseOptimizedLibcall) {
1280         // Value is returned directly.
1281         // The function returns an appropriately sized integer type.
1282         RetTy = getContext().getIntTypeForBitwidth(
1283             getContext().toBits(TInfo.Width), /*Signed=*/false);
1284       } else {
1285         // Value is returned through parameter before the order.
1286         RetTy = getContext().VoidTy;
1287         Args.add(RValue::get(EmitCastToVoidPtr(Dest.getPointer())),
1288                  getContext().VoidPtrTy);
1289       }
1290     }
1291     // order is always the last parameter
1292     Args.add(RValue::get(Order),
1293              getContext().IntTy);
1294     if (E->isOpenCL())
1295       Args.add(RValue::get(Scope), getContext().IntTy);
1296 
1297     // PostOp is only needed for the atomic_*_fetch operations, and
1298     // thus is only needed for and implemented in the
1299     // UseOptimizedLibcall codepath.
1300     assert(UseOptimizedLibcall || (!PostOp && !PostOpMinMax));
1301 
1302     RValue Res = emitAtomicLibcall(*this, LibCallName, RetTy, Args);
1303     // The value is returned directly from the libcall.
1304     if (E->isCmpXChg())
1305       return Res;
1306 
1307     // The value is returned directly for optimized libcalls but the expr
1308     // provided an out-param.
1309     if (UseOptimizedLibcall && Res.getScalarVal()) {
1310       llvm::Value *ResVal = Res.getScalarVal();
1311       if (PostOpMinMax) {
1312         llvm::Value *LoadVal1 = Args[1].getRValue(*this).getScalarVal();
1313         ResVal = EmitPostAtomicMinMax(Builder, E->getOp(),
1314                                       E->getValueType()->isSignedIntegerType(),
1315                                       ResVal, LoadVal1);
1316       } else if (PostOp) {
1317         llvm::Value *LoadVal1 = Args[1].getRValue(*this).getScalarVal();
1318         ResVal = Builder.CreateBinOp(PostOp, ResVal, LoadVal1);
1319       }
1320       if (E->getOp() == AtomicExpr::AO__atomic_nand_fetch)
1321         ResVal = Builder.CreateNot(ResVal);
1322 
1323       Builder.CreateStore(
1324           ResVal,
1325           Builder.CreateBitCast(Dest, ResVal->getType()->getPointerTo()));
1326     }
1327 
1328     if (RValTy->isVoidType())
1329       return RValue::get(nullptr);
1330 
1331     return convertTempToRValue(
1332         Builder.CreateBitCast(Dest, ConvertTypeForMem(RValTy)->getPointerTo()),
1333         RValTy, E->getExprLoc());
1334   }
1335 
1336   bool IsStore = E->getOp() == AtomicExpr::AO__c11_atomic_store ||
1337                  E->getOp() == AtomicExpr::AO__opencl_atomic_store ||
1338                  E->getOp() == AtomicExpr::AO__hip_atomic_store ||
1339                  E->getOp() == AtomicExpr::AO__atomic_store ||
1340                  E->getOp() == AtomicExpr::AO__atomic_store_n;
1341   bool IsLoad = E->getOp() == AtomicExpr::AO__c11_atomic_load ||
1342                 E->getOp() == AtomicExpr::AO__opencl_atomic_load ||
1343                 E->getOp() == AtomicExpr::AO__hip_atomic_load ||
1344                 E->getOp() == AtomicExpr::AO__atomic_load ||
1345                 E->getOp() == AtomicExpr::AO__atomic_load_n;
1346 
1347   if (isa<llvm::ConstantInt>(Order)) {
1348     auto ord = cast<llvm::ConstantInt>(Order)->getZExtValue();
1349     // We should not ever get to a case where the ordering isn't a valid C ABI
1350     // value, but it's hard to enforce that in general.
1351     if (llvm::isValidAtomicOrderingCABI(ord))
1352       switch ((llvm::AtomicOrderingCABI)ord) {
1353       case llvm::AtomicOrderingCABI::relaxed:
1354         EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size,
1355                      llvm::AtomicOrdering::Monotonic, Scope);
1356         break;
1357       case llvm::AtomicOrderingCABI::consume:
1358       case llvm::AtomicOrderingCABI::acquire:
1359         if (IsStore)
1360           break; // Avoid crashing on code with undefined behavior
1361         EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size,
1362                      llvm::AtomicOrdering::Acquire, Scope);
1363         break;
1364       case llvm::AtomicOrderingCABI::release:
1365         if (IsLoad)
1366           break; // Avoid crashing on code with undefined behavior
1367         EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size,
1368                      llvm::AtomicOrdering::Release, Scope);
1369         break;
1370       case llvm::AtomicOrderingCABI::acq_rel:
1371         if (IsLoad || IsStore)
1372           break; // Avoid crashing on code with undefined behavior
1373         EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size,
1374                      llvm::AtomicOrdering::AcquireRelease, Scope);
1375         break;
1376       case llvm::AtomicOrderingCABI::seq_cst:
1377         EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size,
1378                      llvm::AtomicOrdering::SequentiallyConsistent, Scope);
1379         break;
1380       }
1381     if (RValTy->isVoidType())
1382       return RValue::get(nullptr);
1383 
1384     return convertTempToRValue(
1385         Builder.CreateBitCast(Dest, ConvertTypeForMem(RValTy)->getPointerTo(
1386                                         Dest.getAddressSpace())),
1387         RValTy, E->getExprLoc());
1388   }
1389 
1390   // Long case, when Order isn't obviously constant.
1391 
1392   // Create all the relevant BB's
1393   llvm::BasicBlock *MonotonicBB = nullptr, *AcquireBB = nullptr,
1394                    *ReleaseBB = nullptr, *AcqRelBB = nullptr,
1395                    *SeqCstBB = nullptr;
1396   MonotonicBB = createBasicBlock("monotonic", CurFn);
1397   if (!IsStore)
1398     AcquireBB = createBasicBlock("acquire", CurFn);
1399   if (!IsLoad)
1400     ReleaseBB = createBasicBlock("release", CurFn);
1401   if (!IsLoad && !IsStore)
1402     AcqRelBB = createBasicBlock("acqrel", CurFn);
1403   SeqCstBB = createBasicBlock("seqcst", CurFn);
1404   llvm::BasicBlock *ContBB = createBasicBlock("atomic.continue", CurFn);
1405 
1406   // Create the switch for the split
1407   // MonotonicBB is arbitrarily chosen as the default case; in practice, this
1408   // doesn't matter unless someone is crazy enough to use something that
1409   // doesn't fold to a constant for the ordering.
1410   Order = Builder.CreateIntCast(Order, Builder.getInt32Ty(), false);
1411   llvm::SwitchInst *SI = Builder.CreateSwitch(Order, MonotonicBB);
1412 
1413   // Emit all the different atomics
1414   Builder.SetInsertPoint(MonotonicBB);
1415   EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size,
1416                llvm::AtomicOrdering::Monotonic, Scope);
1417   Builder.CreateBr(ContBB);
1418   if (!IsStore) {
1419     Builder.SetInsertPoint(AcquireBB);
1420     EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size,
1421                  llvm::AtomicOrdering::Acquire, Scope);
1422     Builder.CreateBr(ContBB);
1423     SI->addCase(Builder.getInt32((int)llvm::AtomicOrderingCABI::consume),
1424                 AcquireBB);
1425     SI->addCase(Builder.getInt32((int)llvm::AtomicOrderingCABI::acquire),
1426                 AcquireBB);
1427   }
1428   if (!IsLoad) {
1429     Builder.SetInsertPoint(ReleaseBB);
1430     EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size,
1431                  llvm::AtomicOrdering::Release, Scope);
1432     Builder.CreateBr(ContBB);
1433     SI->addCase(Builder.getInt32((int)llvm::AtomicOrderingCABI::release),
1434                 ReleaseBB);
1435   }
1436   if (!IsLoad && !IsStore) {
1437     Builder.SetInsertPoint(AcqRelBB);
1438     EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size,
1439                  llvm::AtomicOrdering::AcquireRelease, Scope);
1440     Builder.CreateBr(ContBB);
1441     SI->addCase(Builder.getInt32((int)llvm::AtomicOrderingCABI::acq_rel),
1442                 AcqRelBB);
1443   }
1444   Builder.SetInsertPoint(SeqCstBB);
1445   EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size,
1446                llvm::AtomicOrdering::SequentiallyConsistent, Scope);
1447   Builder.CreateBr(ContBB);
1448   SI->addCase(Builder.getInt32((int)llvm::AtomicOrderingCABI::seq_cst),
1449               SeqCstBB);
1450 
1451   // Cleanup and return
1452   Builder.SetInsertPoint(ContBB);
1453   if (RValTy->isVoidType())
1454     return RValue::get(nullptr);
1455 
1456   assert(Atomics.getValueSizeInBits() <= Atomics.getAtomicSizeInBits());
1457   return convertTempToRValue(
1458       Builder.CreateBitCast(Dest, ConvertTypeForMem(RValTy)->getPointerTo(
1459                                       Dest.getAddressSpace())),
1460       RValTy, E->getExprLoc());
1461 }
1462 
1463 Address AtomicInfo::emitCastToAtomicIntPointer(Address addr) const {
1464   unsigned addrspace =
1465     cast<llvm::PointerType>(addr.getPointer()->getType())->getAddressSpace();
1466   llvm::IntegerType *ty =
1467     llvm::IntegerType::get(CGF.getLLVMContext(), AtomicSizeInBits);
1468   return CGF.Builder.CreateBitCast(addr, ty->getPointerTo(addrspace));
1469 }
1470 
1471 Address AtomicInfo::convertToAtomicIntPointer(Address Addr) const {
1472   llvm::Type *Ty = Addr.getElementType();
1473   uint64_t SourceSizeInBits = CGF.CGM.getDataLayout().getTypeSizeInBits(Ty);
1474   if (SourceSizeInBits != AtomicSizeInBits) {
1475     Address Tmp = CreateTempAlloca();
1476     CGF.Builder.CreateMemCpy(Tmp, Addr,
1477                              std::min(AtomicSizeInBits, SourceSizeInBits) / 8);
1478     Addr = Tmp;
1479   }
1480 
1481   return emitCastToAtomicIntPointer(Addr);
1482 }
1483 
1484 RValue AtomicInfo::convertAtomicTempToRValue(Address addr,
1485                                              AggValueSlot resultSlot,
1486                                              SourceLocation loc,
1487                                              bool asValue) const {
1488   if (LVal.isSimple()) {
1489     if (EvaluationKind == TEK_Aggregate)
1490       return resultSlot.asRValue();
1491 
1492     // Drill into the padding structure if we have one.
1493     if (hasPadding())
1494       addr = CGF.Builder.CreateStructGEP(addr, 0);
1495 
1496     // Otherwise, just convert the temporary to an r-value using the
1497     // normal conversion routine.
1498     return CGF.convertTempToRValue(addr, getValueType(), loc);
1499   }
1500   if (!asValue)
1501     // Get RValue from temp memory as atomic for non-simple lvalues
1502     return RValue::get(CGF.Builder.CreateLoad(addr));
1503   if (LVal.isBitField())
1504     return CGF.EmitLoadOfBitfieldLValue(
1505         LValue::MakeBitfield(addr, LVal.getBitFieldInfo(), LVal.getType(),
1506                              LVal.getBaseInfo(), TBAAAccessInfo()), loc);
1507   if (LVal.isVectorElt())
1508     return CGF.EmitLoadOfLValue(
1509         LValue::MakeVectorElt(addr, LVal.getVectorIdx(), LVal.getType(),
1510                               LVal.getBaseInfo(), TBAAAccessInfo()), loc);
1511   assert(LVal.isExtVectorElt());
1512   return CGF.EmitLoadOfExtVectorElementLValue(LValue::MakeExtVectorElt(
1513       addr, LVal.getExtVectorElts(), LVal.getType(),
1514       LVal.getBaseInfo(), TBAAAccessInfo()));
1515 }
1516 
1517 RValue AtomicInfo::ConvertIntToValueOrAtomic(llvm::Value *IntVal,
1518                                              AggValueSlot ResultSlot,
1519                                              SourceLocation Loc,
1520                                              bool AsValue) const {
1521   // Try not to in some easy cases.
1522   assert(IntVal->getType()->isIntegerTy() && "Expected integer value");
1523   if (getEvaluationKind() == TEK_Scalar &&
1524       (((!LVal.isBitField() ||
1525          LVal.getBitFieldInfo().Size == ValueSizeInBits) &&
1526         !hasPadding()) ||
1527        !AsValue)) {
1528     auto *ValTy = AsValue
1529                       ? CGF.ConvertTypeForMem(ValueTy)
1530                       : getAtomicAddress().getType()->getPointerElementType();
1531     if (ValTy->isIntegerTy()) {
1532       assert(IntVal->getType() == ValTy && "Different integer types.");
1533       return RValue::get(CGF.EmitFromMemory(IntVal, ValueTy));
1534     } else if (ValTy->isPointerTy())
1535       return RValue::get(CGF.Builder.CreateIntToPtr(IntVal, ValTy));
1536     else if (llvm::CastInst::isBitCastable(IntVal->getType(), ValTy))
1537       return RValue::get(CGF.Builder.CreateBitCast(IntVal, ValTy));
1538   }
1539 
1540   // Create a temporary.  This needs to be big enough to hold the
1541   // atomic integer.
1542   Address Temp = Address::invalid();
1543   bool TempIsVolatile = false;
1544   if (AsValue && getEvaluationKind() == TEK_Aggregate) {
1545     assert(!ResultSlot.isIgnored());
1546     Temp = ResultSlot.getAddress();
1547     TempIsVolatile = ResultSlot.isVolatile();
1548   } else {
1549     Temp = CreateTempAlloca();
1550   }
1551 
1552   // Slam the integer into the temporary.
1553   Address CastTemp = emitCastToAtomicIntPointer(Temp);
1554   CGF.Builder.CreateStore(IntVal, CastTemp)
1555       ->setVolatile(TempIsVolatile);
1556 
1557   return convertAtomicTempToRValue(Temp, ResultSlot, Loc, AsValue);
1558 }
1559 
1560 void AtomicInfo::EmitAtomicLoadLibcall(llvm::Value *AddForLoaded,
1561                                        llvm::AtomicOrdering AO, bool) {
1562   // void __atomic_load(size_t size, void *mem, void *return, int order);
1563   CallArgList Args;
1564   Args.add(RValue::get(getAtomicSizeValue()), CGF.getContext().getSizeType());
1565   Args.add(RValue::get(CGF.EmitCastToVoidPtr(getAtomicPointer())),
1566            CGF.getContext().VoidPtrTy);
1567   Args.add(RValue::get(CGF.EmitCastToVoidPtr(AddForLoaded)),
1568            CGF.getContext().VoidPtrTy);
1569   Args.add(
1570       RValue::get(llvm::ConstantInt::get(CGF.IntTy, (int)llvm::toCABI(AO))),
1571       CGF.getContext().IntTy);
1572   emitAtomicLibcall(CGF, "__atomic_load", CGF.getContext().VoidTy, Args);
1573 }
1574 
1575 llvm::Value *AtomicInfo::EmitAtomicLoadOp(llvm::AtomicOrdering AO,
1576                                           bool IsVolatile) {
1577   // Okay, we're doing this natively.
1578   Address Addr = getAtomicAddressAsAtomicIntPointer();
1579   llvm::LoadInst *Load = CGF.Builder.CreateLoad(Addr, "atomic-load");
1580   Load->setAtomic(AO);
1581 
1582   // Other decoration.
1583   if (IsVolatile)
1584     Load->setVolatile(true);
1585   CGF.CGM.DecorateInstructionWithTBAA(Load, LVal.getTBAAInfo());
1586   return Load;
1587 }
1588 
1589 /// An LValue is a candidate for having its loads and stores be made atomic if
1590 /// we are operating under /volatile:ms *and* the LValue itself is volatile and
1591 /// performing such an operation can be performed without a libcall.
1592 bool CodeGenFunction::LValueIsSuitableForInlineAtomic(LValue LV) {
1593   if (!CGM.getCodeGenOpts().MSVolatile) return false;
1594   AtomicInfo AI(*this, LV);
1595   bool IsVolatile = LV.isVolatile() || hasVolatileMember(LV.getType());
1596   // An atomic is inline if we don't need to use a libcall.
1597   bool AtomicIsInline = !AI.shouldUseLibcall();
1598   // MSVC doesn't seem to do this for types wider than a pointer.
1599   if (getContext().getTypeSize(LV.getType()) >
1600       getContext().getTypeSize(getContext().getIntPtrType()))
1601     return false;
1602   return IsVolatile && AtomicIsInline;
1603 }
1604 
1605 RValue CodeGenFunction::EmitAtomicLoad(LValue LV, SourceLocation SL,
1606                                        AggValueSlot Slot) {
1607   llvm::AtomicOrdering AO;
1608   bool IsVolatile = LV.isVolatileQualified();
1609   if (LV.getType()->isAtomicType()) {
1610     AO = llvm::AtomicOrdering::SequentiallyConsistent;
1611   } else {
1612     AO = llvm::AtomicOrdering::Acquire;
1613     IsVolatile = true;
1614   }
1615   return EmitAtomicLoad(LV, SL, AO, IsVolatile, Slot);
1616 }
1617 
1618 RValue AtomicInfo::EmitAtomicLoad(AggValueSlot ResultSlot, SourceLocation Loc,
1619                                   bool AsValue, llvm::AtomicOrdering AO,
1620                                   bool IsVolatile) {
1621   // Check whether we should use a library call.
1622   if (shouldUseLibcall()) {
1623     Address TempAddr = Address::invalid();
1624     if (LVal.isSimple() && !ResultSlot.isIgnored()) {
1625       assert(getEvaluationKind() == TEK_Aggregate);
1626       TempAddr = ResultSlot.getAddress();
1627     } else
1628       TempAddr = CreateTempAlloca();
1629 
1630     EmitAtomicLoadLibcall(TempAddr.getPointer(), AO, IsVolatile);
1631 
1632     // Okay, turn that back into the original value or whole atomic (for
1633     // non-simple lvalues) type.
1634     return convertAtomicTempToRValue(TempAddr, ResultSlot, Loc, AsValue);
1635   }
1636 
1637   // Okay, we're doing this natively.
1638   auto *Load = EmitAtomicLoadOp(AO, IsVolatile);
1639 
1640   // If we're ignoring an aggregate return, don't do anything.
1641   if (getEvaluationKind() == TEK_Aggregate && ResultSlot.isIgnored())
1642     return RValue::getAggregate(Address::invalid(), false);
1643 
1644   // Okay, turn that back into the original value or atomic (for non-simple
1645   // lvalues) type.
1646   return ConvertIntToValueOrAtomic(Load, ResultSlot, Loc, AsValue);
1647 }
1648 
1649 /// Emit a load from an l-value of atomic type.  Note that the r-value
1650 /// we produce is an r-value of the atomic *value* type.
1651 RValue CodeGenFunction::EmitAtomicLoad(LValue src, SourceLocation loc,
1652                                        llvm::AtomicOrdering AO, bool IsVolatile,
1653                                        AggValueSlot resultSlot) {
1654   AtomicInfo Atomics(*this, src);
1655   return Atomics.EmitAtomicLoad(resultSlot, loc, /*AsValue=*/true, AO,
1656                                 IsVolatile);
1657 }
1658 
1659 /// Copy an r-value into memory as part of storing to an atomic type.
1660 /// This needs to create a bit-pattern suitable for atomic operations.
1661 void AtomicInfo::emitCopyIntoMemory(RValue rvalue) const {
1662   assert(LVal.isSimple());
1663   // If we have an r-value, the rvalue should be of the atomic type,
1664   // which means that the caller is responsible for having zeroed
1665   // any padding.  Just do an aggregate copy of that type.
1666   if (rvalue.isAggregate()) {
1667     LValue Dest = CGF.MakeAddrLValue(getAtomicAddress(), getAtomicType());
1668     LValue Src = CGF.MakeAddrLValue(rvalue.getAggregateAddress(),
1669                                     getAtomicType());
1670     bool IsVolatile = rvalue.isVolatileQualified() ||
1671                       LVal.isVolatileQualified();
1672     CGF.EmitAggregateCopy(Dest, Src, getAtomicType(),
1673                           AggValueSlot::DoesNotOverlap, IsVolatile);
1674     return;
1675   }
1676 
1677   // Okay, otherwise we're copying stuff.
1678 
1679   // Zero out the buffer if necessary.
1680   emitMemSetZeroIfNecessary();
1681 
1682   // Drill past the padding if present.
1683   LValue TempLVal = projectValue();
1684 
1685   // Okay, store the rvalue in.
1686   if (rvalue.isScalar()) {
1687     CGF.EmitStoreOfScalar(rvalue.getScalarVal(), TempLVal, /*init*/ true);
1688   } else {
1689     CGF.EmitStoreOfComplex(rvalue.getComplexVal(), TempLVal, /*init*/ true);
1690   }
1691 }
1692 
1693 
1694 /// Materialize an r-value into memory for the purposes of storing it
1695 /// to an atomic type.
1696 Address AtomicInfo::materializeRValue(RValue rvalue) const {
1697   // Aggregate r-values are already in memory, and EmitAtomicStore
1698   // requires them to be values of the atomic type.
1699   if (rvalue.isAggregate())
1700     return rvalue.getAggregateAddress();
1701 
1702   // Otherwise, make a temporary and materialize into it.
1703   LValue TempLV = CGF.MakeAddrLValue(CreateTempAlloca(), getAtomicType());
1704   AtomicInfo Atomics(CGF, TempLV);
1705   Atomics.emitCopyIntoMemory(rvalue);
1706   return TempLV.getAddress(CGF);
1707 }
1708 
1709 llvm::Value *AtomicInfo::convertRValueToInt(RValue RVal) const {
1710   // If we've got a scalar value of the right size, try to avoid going
1711   // through memory.
1712   if (RVal.isScalar() && (!hasPadding() || !LVal.isSimple())) {
1713     llvm::Value *Value = RVal.getScalarVal();
1714     if (isa<llvm::IntegerType>(Value->getType()))
1715       return CGF.EmitToMemory(Value, ValueTy);
1716     else {
1717       llvm::IntegerType *InputIntTy = llvm::IntegerType::get(
1718           CGF.getLLVMContext(),
1719           LVal.isSimple() ? getValueSizeInBits() : getAtomicSizeInBits());
1720       if (isa<llvm::PointerType>(Value->getType()))
1721         return CGF.Builder.CreatePtrToInt(Value, InputIntTy);
1722       else if (llvm::BitCastInst::isBitCastable(Value->getType(), InputIntTy))
1723         return CGF.Builder.CreateBitCast(Value, InputIntTy);
1724     }
1725   }
1726   // Otherwise, we need to go through memory.
1727   // Put the r-value in memory.
1728   Address Addr = materializeRValue(RVal);
1729 
1730   // Cast the temporary to the atomic int type and pull a value out.
1731   Addr = emitCastToAtomicIntPointer(Addr);
1732   return CGF.Builder.CreateLoad(Addr);
1733 }
1734 
1735 std::pair<llvm::Value *, llvm::Value *> AtomicInfo::EmitAtomicCompareExchangeOp(
1736     llvm::Value *ExpectedVal, llvm::Value *DesiredVal,
1737     llvm::AtomicOrdering Success, llvm::AtomicOrdering Failure, bool IsWeak) {
1738   // Do the atomic store.
1739   Address Addr = getAtomicAddressAsAtomicIntPointer();
1740   auto *Inst = CGF.Builder.CreateAtomicCmpXchg(Addr.getPointer(),
1741                                                ExpectedVal, DesiredVal,
1742                                                Success, Failure);
1743   // Other decoration.
1744   Inst->setVolatile(LVal.isVolatileQualified());
1745   Inst->setWeak(IsWeak);
1746 
1747   // Okay, turn that back into the original value type.
1748   auto *PreviousVal = CGF.Builder.CreateExtractValue(Inst, /*Idxs=*/0);
1749   auto *SuccessFailureVal = CGF.Builder.CreateExtractValue(Inst, /*Idxs=*/1);
1750   return std::make_pair(PreviousVal, SuccessFailureVal);
1751 }
1752 
1753 llvm::Value *
1754 AtomicInfo::EmitAtomicCompareExchangeLibcall(llvm::Value *ExpectedAddr,
1755                                              llvm::Value *DesiredAddr,
1756                                              llvm::AtomicOrdering Success,
1757                                              llvm::AtomicOrdering Failure) {
1758   // bool __atomic_compare_exchange(size_t size, void *obj, void *expected,
1759   // void *desired, int success, int failure);
1760   CallArgList Args;
1761   Args.add(RValue::get(getAtomicSizeValue()), CGF.getContext().getSizeType());
1762   Args.add(RValue::get(CGF.EmitCastToVoidPtr(getAtomicPointer())),
1763            CGF.getContext().VoidPtrTy);
1764   Args.add(RValue::get(CGF.EmitCastToVoidPtr(ExpectedAddr)),
1765            CGF.getContext().VoidPtrTy);
1766   Args.add(RValue::get(CGF.EmitCastToVoidPtr(DesiredAddr)),
1767            CGF.getContext().VoidPtrTy);
1768   Args.add(RValue::get(
1769                llvm::ConstantInt::get(CGF.IntTy, (int)llvm::toCABI(Success))),
1770            CGF.getContext().IntTy);
1771   Args.add(RValue::get(
1772                llvm::ConstantInt::get(CGF.IntTy, (int)llvm::toCABI(Failure))),
1773            CGF.getContext().IntTy);
1774   auto SuccessFailureRVal = emitAtomicLibcall(CGF, "__atomic_compare_exchange",
1775                                               CGF.getContext().BoolTy, Args);
1776 
1777   return SuccessFailureRVal.getScalarVal();
1778 }
1779 
1780 std::pair<RValue, llvm::Value *> AtomicInfo::EmitAtomicCompareExchange(
1781     RValue Expected, RValue Desired, llvm::AtomicOrdering Success,
1782     llvm::AtomicOrdering Failure, bool IsWeak) {
1783   // Check whether we should use a library call.
1784   if (shouldUseLibcall()) {
1785     // Produce a source address.
1786     Address ExpectedAddr = materializeRValue(Expected);
1787     Address DesiredAddr = materializeRValue(Desired);
1788     auto *Res = EmitAtomicCompareExchangeLibcall(ExpectedAddr.getPointer(),
1789                                                  DesiredAddr.getPointer(),
1790                                                  Success, Failure);
1791     return std::make_pair(
1792         convertAtomicTempToRValue(ExpectedAddr, AggValueSlot::ignored(),
1793                                   SourceLocation(), /*AsValue=*/false),
1794         Res);
1795   }
1796 
1797   // If we've got a scalar value of the right size, try to avoid going
1798   // through memory.
1799   auto *ExpectedVal = convertRValueToInt(Expected);
1800   auto *DesiredVal = convertRValueToInt(Desired);
1801   auto Res = EmitAtomicCompareExchangeOp(ExpectedVal, DesiredVal, Success,
1802                                          Failure, IsWeak);
1803   return std::make_pair(
1804       ConvertIntToValueOrAtomic(Res.first, AggValueSlot::ignored(),
1805                                 SourceLocation(), /*AsValue=*/false),
1806       Res.second);
1807 }
1808 
1809 static void
1810 EmitAtomicUpdateValue(CodeGenFunction &CGF, AtomicInfo &Atomics, RValue OldRVal,
1811                       const llvm::function_ref<RValue(RValue)> &UpdateOp,
1812                       Address DesiredAddr) {
1813   RValue UpRVal;
1814   LValue AtomicLVal = Atomics.getAtomicLValue();
1815   LValue DesiredLVal;
1816   if (AtomicLVal.isSimple()) {
1817     UpRVal = OldRVal;
1818     DesiredLVal = CGF.MakeAddrLValue(DesiredAddr, AtomicLVal.getType());
1819   } else {
1820     // Build new lvalue for temp address.
1821     Address Ptr = Atomics.materializeRValue(OldRVal);
1822     LValue UpdateLVal;
1823     if (AtomicLVal.isBitField()) {
1824       UpdateLVal =
1825           LValue::MakeBitfield(Ptr, AtomicLVal.getBitFieldInfo(),
1826                                AtomicLVal.getType(),
1827                                AtomicLVal.getBaseInfo(),
1828                                AtomicLVal.getTBAAInfo());
1829       DesiredLVal =
1830           LValue::MakeBitfield(DesiredAddr, AtomicLVal.getBitFieldInfo(),
1831                                AtomicLVal.getType(), AtomicLVal.getBaseInfo(),
1832                                AtomicLVal.getTBAAInfo());
1833     } else if (AtomicLVal.isVectorElt()) {
1834       UpdateLVal = LValue::MakeVectorElt(Ptr, AtomicLVal.getVectorIdx(),
1835                                          AtomicLVal.getType(),
1836                                          AtomicLVal.getBaseInfo(),
1837                                          AtomicLVal.getTBAAInfo());
1838       DesiredLVal = LValue::MakeVectorElt(
1839           DesiredAddr, AtomicLVal.getVectorIdx(), AtomicLVal.getType(),
1840           AtomicLVal.getBaseInfo(), AtomicLVal.getTBAAInfo());
1841     } else {
1842       assert(AtomicLVal.isExtVectorElt());
1843       UpdateLVal = LValue::MakeExtVectorElt(Ptr, AtomicLVal.getExtVectorElts(),
1844                                             AtomicLVal.getType(),
1845                                             AtomicLVal.getBaseInfo(),
1846                                             AtomicLVal.getTBAAInfo());
1847       DesiredLVal = LValue::MakeExtVectorElt(
1848           DesiredAddr, AtomicLVal.getExtVectorElts(), AtomicLVal.getType(),
1849           AtomicLVal.getBaseInfo(), AtomicLVal.getTBAAInfo());
1850     }
1851     UpRVal = CGF.EmitLoadOfLValue(UpdateLVal, SourceLocation());
1852   }
1853   // Store new value in the corresponding memory area.
1854   RValue NewRVal = UpdateOp(UpRVal);
1855   if (NewRVal.isScalar()) {
1856     CGF.EmitStoreThroughLValue(NewRVal, DesiredLVal);
1857   } else {
1858     assert(NewRVal.isComplex());
1859     CGF.EmitStoreOfComplex(NewRVal.getComplexVal(), DesiredLVal,
1860                            /*isInit=*/false);
1861   }
1862 }
1863 
1864 void AtomicInfo::EmitAtomicUpdateLibcall(
1865     llvm::AtomicOrdering AO, const llvm::function_ref<RValue(RValue)> &UpdateOp,
1866     bool IsVolatile) {
1867   auto Failure = llvm::AtomicCmpXchgInst::getStrongestFailureOrdering(AO);
1868 
1869   Address ExpectedAddr = CreateTempAlloca();
1870 
1871   EmitAtomicLoadLibcall(ExpectedAddr.getPointer(), AO, IsVolatile);
1872   auto *ContBB = CGF.createBasicBlock("atomic_cont");
1873   auto *ExitBB = CGF.createBasicBlock("atomic_exit");
1874   CGF.EmitBlock(ContBB);
1875   Address DesiredAddr = CreateTempAlloca();
1876   if ((LVal.isBitField() && BFI.Size != ValueSizeInBits) ||
1877       requiresMemSetZero(getAtomicAddress().getElementType())) {
1878     auto *OldVal = CGF.Builder.CreateLoad(ExpectedAddr);
1879     CGF.Builder.CreateStore(OldVal, DesiredAddr);
1880   }
1881   auto OldRVal = convertAtomicTempToRValue(ExpectedAddr,
1882                                            AggValueSlot::ignored(),
1883                                            SourceLocation(), /*AsValue=*/false);
1884   EmitAtomicUpdateValue(CGF, *this, OldRVal, UpdateOp, DesiredAddr);
1885   auto *Res =
1886       EmitAtomicCompareExchangeLibcall(ExpectedAddr.getPointer(),
1887                                        DesiredAddr.getPointer(),
1888                                        AO, Failure);
1889   CGF.Builder.CreateCondBr(Res, ExitBB, ContBB);
1890   CGF.EmitBlock(ExitBB, /*IsFinished=*/true);
1891 }
1892 
1893 void AtomicInfo::EmitAtomicUpdateOp(
1894     llvm::AtomicOrdering AO, const llvm::function_ref<RValue(RValue)> &UpdateOp,
1895     bool IsVolatile) {
1896   auto Failure = llvm::AtomicCmpXchgInst::getStrongestFailureOrdering(AO);
1897 
1898   // Do the atomic load.
1899   auto *OldVal = EmitAtomicLoadOp(Failure, IsVolatile);
1900   // For non-simple lvalues perform compare-and-swap procedure.
1901   auto *ContBB = CGF.createBasicBlock("atomic_cont");
1902   auto *ExitBB = CGF.createBasicBlock("atomic_exit");
1903   auto *CurBB = CGF.Builder.GetInsertBlock();
1904   CGF.EmitBlock(ContBB);
1905   llvm::PHINode *PHI = CGF.Builder.CreatePHI(OldVal->getType(),
1906                                              /*NumReservedValues=*/2);
1907   PHI->addIncoming(OldVal, CurBB);
1908   Address NewAtomicAddr = CreateTempAlloca();
1909   Address NewAtomicIntAddr = emitCastToAtomicIntPointer(NewAtomicAddr);
1910   if ((LVal.isBitField() && BFI.Size != ValueSizeInBits) ||
1911       requiresMemSetZero(getAtomicAddress().getElementType())) {
1912     CGF.Builder.CreateStore(PHI, NewAtomicIntAddr);
1913   }
1914   auto OldRVal = ConvertIntToValueOrAtomic(PHI, AggValueSlot::ignored(),
1915                                            SourceLocation(), /*AsValue=*/false);
1916   EmitAtomicUpdateValue(CGF, *this, OldRVal, UpdateOp, NewAtomicAddr);
1917   auto *DesiredVal = CGF.Builder.CreateLoad(NewAtomicIntAddr);
1918   // Try to write new value using cmpxchg operation.
1919   auto Res = EmitAtomicCompareExchangeOp(PHI, DesiredVal, AO, Failure);
1920   PHI->addIncoming(Res.first, CGF.Builder.GetInsertBlock());
1921   CGF.Builder.CreateCondBr(Res.second, ExitBB, ContBB);
1922   CGF.EmitBlock(ExitBB, /*IsFinished=*/true);
1923 }
1924 
1925 static void EmitAtomicUpdateValue(CodeGenFunction &CGF, AtomicInfo &Atomics,
1926                                   RValue UpdateRVal, Address DesiredAddr) {
1927   LValue AtomicLVal = Atomics.getAtomicLValue();
1928   LValue DesiredLVal;
1929   // Build new lvalue for temp address.
1930   if (AtomicLVal.isBitField()) {
1931     DesiredLVal =
1932         LValue::MakeBitfield(DesiredAddr, AtomicLVal.getBitFieldInfo(),
1933                              AtomicLVal.getType(), AtomicLVal.getBaseInfo(),
1934                              AtomicLVal.getTBAAInfo());
1935   } else if (AtomicLVal.isVectorElt()) {
1936     DesiredLVal =
1937         LValue::MakeVectorElt(DesiredAddr, AtomicLVal.getVectorIdx(),
1938                               AtomicLVal.getType(), AtomicLVal.getBaseInfo(),
1939                               AtomicLVal.getTBAAInfo());
1940   } else {
1941     assert(AtomicLVal.isExtVectorElt());
1942     DesiredLVal = LValue::MakeExtVectorElt(
1943         DesiredAddr, AtomicLVal.getExtVectorElts(), AtomicLVal.getType(),
1944         AtomicLVal.getBaseInfo(), AtomicLVal.getTBAAInfo());
1945   }
1946   // Store new value in the corresponding memory area.
1947   assert(UpdateRVal.isScalar());
1948   CGF.EmitStoreThroughLValue(UpdateRVal, DesiredLVal);
1949 }
1950 
1951 void AtomicInfo::EmitAtomicUpdateLibcall(llvm::AtomicOrdering AO,
1952                                          RValue UpdateRVal, bool IsVolatile) {
1953   auto Failure = llvm::AtomicCmpXchgInst::getStrongestFailureOrdering(AO);
1954 
1955   Address ExpectedAddr = CreateTempAlloca();
1956 
1957   EmitAtomicLoadLibcall(ExpectedAddr.getPointer(), AO, IsVolatile);
1958   auto *ContBB = CGF.createBasicBlock("atomic_cont");
1959   auto *ExitBB = CGF.createBasicBlock("atomic_exit");
1960   CGF.EmitBlock(ContBB);
1961   Address DesiredAddr = CreateTempAlloca();
1962   if ((LVal.isBitField() && BFI.Size != ValueSizeInBits) ||
1963       requiresMemSetZero(getAtomicAddress().getElementType())) {
1964     auto *OldVal = CGF.Builder.CreateLoad(ExpectedAddr);
1965     CGF.Builder.CreateStore(OldVal, DesiredAddr);
1966   }
1967   EmitAtomicUpdateValue(CGF, *this, UpdateRVal, DesiredAddr);
1968   auto *Res =
1969       EmitAtomicCompareExchangeLibcall(ExpectedAddr.getPointer(),
1970                                        DesiredAddr.getPointer(),
1971                                        AO, Failure);
1972   CGF.Builder.CreateCondBr(Res, ExitBB, ContBB);
1973   CGF.EmitBlock(ExitBB, /*IsFinished=*/true);
1974 }
1975 
1976 void AtomicInfo::EmitAtomicUpdateOp(llvm::AtomicOrdering AO, RValue UpdateRVal,
1977                                     bool IsVolatile) {
1978   auto Failure = llvm::AtomicCmpXchgInst::getStrongestFailureOrdering(AO);
1979 
1980   // Do the atomic load.
1981   auto *OldVal = EmitAtomicLoadOp(Failure, IsVolatile);
1982   // For non-simple lvalues perform compare-and-swap procedure.
1983   auto *ContBB = CGF.createBasicBlock("atomic_cont");
1984   auto *ExitBB = CGF.createBasicBlock("atomic_exit");
1985   auto *CurBB = CGF.Builder.GetInsertBlock();
1986   CGF.EmitBlock(ContBB);
1987   llvm::PHINode *PHI = CGF.Builder.CreatePHI(OldVal->getType(),
1988                                              /*NumReservedValues=*/2);
1989   PHI->addIncoming(OldVal, CurBB);
1990   Address NewAtomicAddr = CreateTempAlloca();
1991   Address NewAtomicIntAddr = emitCastToAtomicIntPointer(NewAtomicAddr);
1992   if ((LVal.isBitField() && BFI.Size != ValueSizeInBits) ||
1993       requiresMemSetZero(getAtomicAddress().getElementType())) {
1994     CGF.Builder.CreateStore(PHI, NewAtomicIntAddr);
1995   }
1996   EmitAtomicUpdateValue(CGF, *this, UpdateRVal, NewAtomicAddr);
1997   auto *DesiredVal = CGF.Builder.CreateLoad(NewAtomicIntAddr);
1998   // Try to write new value using cmpxchg operation.
1999   auto Res = EmitAtomicCompareExchangeOp(PHI, DesiredVal, AO, Failure);
2000   PHI->addIncoming(Res.first, CGF.Builder.GetInsertBlock());
2001   CGF.Builder.CreateCondBr(Res.second, ExitBB, ContBB);
2002   CGF.EmitBlock(ExitBB, /*IsFinished=*/true);
2003 }
2004 
2005 void AtomicInfo::EmitAtomicUpdate(
2006     llvm::AtomicOrdering AO, const llvm::function_ref<RValue(RValue)> &UpdateOp,
2007     bool IsVolatile) {
2008   if (shouldUseLibcall()) {
2009     EmitAtomicUpdateLibcall(AO, UpdateOp, IsVolatile);
2010   } else {
2011     EmitAtomicUpdateOp(AO, UpdateOp, IsVolatile);
2012   }
2013 }
2014 
2015 void AtomicInfo::EmitAtomicUpdate(llvm::AtomicOrdering AO, RValue UpdateRVal,
2016                                   bool IsVolatile) {
2017   if (shouldUseLibcall()) {
2018     EmitAtomicUpdateLibcall(AO, UpdateRVal, IsVolatile);
2019   } else {
2020     EmitAtomicUpdateOp(AO, UpdateRVal, IsVolatile);
2021   }
2022 }
2023 
2024 void CodeGenFunction::EmitAtomicStore(RValue rvalue, LValue lvalue,
2025                                       bool isInit) {
2026   bool IsVolatile = lvalue.isVolatileQualified();
2027   llvm::AtomicOrdering AO;
2028   if (lvalue.getType()->isAtomicType()) {
2029     AO = llvm::AtomicOrdering::SequentiallyConsistent;
2030   } else {
2031     AO = llvm::AtomicOrdering::Release;
2032     IsVolatile = true;
2033   }
2034   return EmitAtomicStore(rvalue, lvalue, AO, IsVolatile, isInit);
2035 }
2036 
2037 /// Emit a store to an l-value of atomic type.
2038 ///
2039 /// Note that the r-value is expected to be an r-value *of the atomic
2040 /// type*; this means that for aggregate r-values, it should include
2041 /// storage for any padding that was necessary.
2042 void CodeGenFunction::EmitAtomicStore(RValue rvalue, LValue dest,
2043                                       llvm::AtomicOrdering AO, bool IsVolatile,
2044                                       bool isInit) {
2045   // If this is an aggregate r-value, it should agree in type except
2046   // maybe for address-space qualification.
2047   assert(!rvalue.isAggregate() ||
2048          rvalue.getAggregateAddress().getElementType() ==
2049              dest.getAddress(*this).getElementType());
2050 
2051   AtomicInfo atomics(*this, dest);
2052   LValue LVal = atomics.getAtomicLValue();
2053 
2054   // If this is an initialization, just put the value there normally.
2055   if (LVal.isSimple()) {
2056     if (isInit) {
2057       atomics.emitCopyIntoMemory(rvalue);
2058       return;
2059     }
2060 
2061     // Check whether we should use a library call.
2062     if (atomics.shouldUseLibcall()) {
2063       // Produce a source address.
2064       Address srcAddr = atomics.materializeRValue(rvalue);
2065 
2066       // void __atomic_store(size_t size, void *mem, void *val, int order)
2067       CallArgList args;
2068       args.add(RValue::get(atomics.getAtomicSizeValue()),
2069                getContext().getSizeType());
2070       args.add(RValue::get(EmitCastToVoidPtr(atomics.getAtomicPointer())),
2071                getContext().VoidPtrTy);
2072       args.add(RValue::get(EmitCastToVoidPtr(srcAddr.getPointer())),
2073                getContext().VoidPtrTy);
2074       args.add(
2075           RValue::get(llvm::ConstantInt::get(IntTy, (int)llvm::toCABI(AO))),
2076           getContext().IntTy);
2077       emitAtomicLibcall(*this, "__atomic_store", getContext().VoidTy, args);
2078       return;
2079     }
2080 
2081     // Okay, we're doing this natively.
2082     llvm::Value *intValue = atomics.convertRValueToInt(rvalue);
2083 
2084     // Do the atomic store.
2085     Address addr =
2086         atomics.emitCastToAtomicIntPointer(atomics.getAtomicAddress());
2087     intValue = Builder.CreateIntCast(
2088         intValue, addr.getElementType(), /*isSigned=*/false);
2089     llvm::StoreInst *store = Builder.CreateStore(intValue, addr);
2090 
2091     if (AO == llvm::AtomicOrdering::Acquire)
2092       AO = llvm::AtomicOrdering::Monotonic;
2093     else if (AO == llvm::AtomicOrdering::AcquireRelease)
2094       AO = llvm::AtomicOrdering::Release;
2095     // Initializations don't need to be atomic.
2096     if (!isInit)
2097       store->setAtomic(AO);
2098 
2099     // Other decoration.
2100     if (IsVolatile)
2101       store->setVolatile(true);
2102     CGM.DecorateInstructionWithTBAA(store, dest.getTBAAInfo());
2103     return;
2104   }
2105 
2106   // Emit simple atomic update operation.
2107   atomics.EmitAtomicUpdate(AO, rvalue, IsVolatile);
2108 }
2109 
2110 /// Emit a compare-and-exchange op for atomic type.
2111 ///
2112 std::pair<RValue, llvm::Value *> CodeGenFunction::EmitAtomicCompareExchange(
2113     LValue Obj, RValue Expected, RValue Desired, SourceLocation Loc,
2114     llvm::AtomicOrdering Success, llvm::AtomicOrdering Failure, bool IsWeak,
2115     AggValueSlot Slot) {
2116   // If this is an aggregate r-value, it should agree in type except
2117   // maybe for address-space qualification.
2118   assert(!Expected.isAggregate() ||
2119          Expected.getAggregateAddress().getElementType() ==
2120              Obj.getAddress(*this).getElementType());
2121   assert(!Desired.isAggregate() ||
2122          Desired.getAggregateAddress().getElementType() ==
2123              Obj.getAddress(*this).getElementType());
2124   AtomicInfo Atomics(*this, Obj);
2125 
2126   return Atomics.EmitAtomicCompareExchange(Expected, Desired, Success, Failure,
2127                                            IsWeak);
2128 }
2129 
2130 void CodeGenFunction::EmitAtomicUpdate(
2131     LValue LVal, llvm::AtomicOrdering AO,
2132     const llvm::function_ref<RValue(RValue)> &UpdateOp, bool IsVolatile) {
2133   AtomicInfo Atomics(*this, LVal);
2134   Atomics.EmitAtomicUpdate(AO, UpdateOp, IsVolatile);
2135 }
2136 
2137 void CodeGenFunction::EmitAtomicInit(Expr *init, LValue dest) {
2138   AtomicInfo atomics(*this, dest);
2139 
2140   switch (atomics.getEvaluationKind()) {
2141   case TEK_Scalar: {
2142     llvm::Value *value = EmitScalarExpr(init);
2143     atomics.emitCopyIntoMemory(RValue::get(value));
2144     return;
2145   }
2146 
2147   case TEK_Complex: {
2148     ComplexPairTy value = EmitComplexExpr(init);
2149     atomics.emitCopyIntoMemory(RValue::getComplex(value));
2150     return;
2151   }
2152 
2153   case TEK_Aggregate: {
2154     // Fix up the destination if the initializer isn't an expression
2155     // of atomic type.
2156     bool Zeroed = false;
2157     if (!init->getType()->isAtomicType()) {
2158       Zeroed = atomics.emitMemSetZeroIfNecessary();
2159       dest = atomics.projectValue();
2160     }
2161 
2162     // Evaluate the expression directly into the destination.
2163     AggValueSlot slot = AggValueSlot::forLValue(
2164         dest, *this, AggValueSlot::IsNotDestructed,
2165         AggValueSlot::DoesNotNeedGCBarriers, AggValueSlot::IsNotAliased,
2166         AggValueSlot::DoesNotOverlap,
2167         Zeroed ? AggValueSlot::IsZeroed : AggValueSlot::IsNotZeroed);
2168 
2169     EmitAggExpr(init, slot);
2170     return;
2171   }
2172   }
2173   llvm_unreachable("bad evaluation kind");
2174 }
2175