1 //===--- CGNonTrivialStruct.cpp - Emit Special Functions for C Structs ----===//
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 defines functions to generate various special functions for C
10 // structs.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "CodeGenFunction.h"
15 #include "CodeGenModule.h"
16 #include "clang/AST/NonTrivialTypeVisitor.h"
17 #include "clang/CodeGen/CodeGenABITypes.h"
18 #include "llvm/Support/ScopedPrinter.h"
19 #include <array>
20 
21 using namespace clang;
22 using namespace CodeGen;
23 
24 // Return the size of a field in number of bits.
25 static uint64_t getFieldSize(const FieldDecl *FD, QualType FT,
26                              ASTContext &Ctx) {
27   if (FD && FD->isBitField())
28     return FD->getBitWidthValue(Ctx);
29   return Ctx.getTypeSize(FT);
30 }
31 
32 namespace {
33 enum { DstIdx = 0, SrcIdx = 1 };
34 const char *ValNameStr[2] = {"dst", "src"};
35 
36 template <class Derived> struct StructVisitor {
37   StructVisitor(ASTContext &Ctx) : Ctx(Ctx) {}
38 
39   template <class... Ts>
40   void visitStructFields(QualType QT, CharUnits CurStructOffset, Ts... Args) {
41     const RecordDecl *RD = QT->castAs<RecordType>()->getDecl();
42 
43     // Iterate over the fields of the struct.
44     for (const FieldDecl *FD : RD->fields()) {
45       QualType FT = FD->getType();
46       FT = QT.isVolatileQualified() ? FT.withVolatile() : FT;
47       asDerived().visit(FT, FD, CurStructOffset, Args...);
48     }
49 
50     asDerived().flushTrivialFields(Args...);
51   }
52 
53   template <class... Ts> void visitTrivial(Ts... Args) {}
54 
55   template <class... Ts> void visitCXXDestructor(Ts... Args) {
56     llvm_unreachable("field of a C++ struct type is not expected");
57   }
58 
59   template <class... Ts> void flushTrivialFields(Ts... Args) {}
60 
61   uint64_t getFieldOffsetInBits(const FieldDecl *FD) {
62     return FD ? Ctx.getASTRecordLayout(FD->getParent())
63                     .getFieldOffset(FD->getFieldIndex())
64               : 0;
65   }
66 
67   CharUnits getFieldOffset(const FieldDecl *FD) {
68     return Ctx.toCharUnitsFromBits(getFieldOffsetInBits(FD));
69   }
70 
71   Derived &asDerived() { return static_cast<Derived &>(*this); }
72 
73   ASTContext &getContext() { return Ctx; }
74   ASTContext &Ctx;
75 };
76 
77 template <class Derived, bool IsMove>
78 struct CopyStructVisitor : StructVisitor<Derived>,
79                            CopiedTypeVisitor<Derived, IsMove> {
80   using StructVisitor<Derived>::asDerived;
81   using Super = CopiedTypeVisitor<Derived, IsMove>;
82 
83   CopyStructVisitor(ASTContext &Ctx) : StructVisitor<Derived>(Ctx) {}
84 
85   template <class... Ts>
86   void preVisit(QualType::PrimitiveCopyKind PCK, QualType FT,
87                 const FieldDecl *FD, CharUnits CurStructOffset, Ts &&... Args) {
88     if (PCK)
89       asDerived().flushTrivialFields(std::forward<Ts>(Args)...);
90   }
91 
92   template <class... Ts>
93   void visitWithKind(QualType::PrimitiveCopyKind PCK, QualType FT,
94                      const FieldDecl *FD, CharUnits CurStructOffset,
95                      Ts &&... Args) {
96     if (const auto *AT = asDerived().getContext().getAsArrayType(FT)) {
97       asDerived().visitArray(PCK, AT, FT.isVolatileQualified(), FD,
98                              CurStructOffset, std::forward<Ts>(Args)...);
99       return;
100     }
101 
102     Super::visitWithKind(PCK, FT, FD, CurStructOffset,
103                          std::forward<Ts>(Args)...);
104   }
105 
106   template <class... Ts>
107   void visitTrivial(QualType FT, const FieldDecl *FD, CharUnits CurStructOffset,
108                     Ts... Args) {
109     assert(!FT.isVolatileQualified() && "volatile field not expected");
110     ASTContext &Ctx = asDerived().getContext();
111     uint64_t FieldSize = getFieldSize(FD, FT, Ctx);
112 
113     // Ignore zero-sized fields.
114     if (FieldSize == 0)
115       return;
116 
117     uint64_t FStartInBits = asDerived().getFieldOffsetInBits(FD);
118     uint64_t FEndInBits = FStartInBits + FieldSize;
119     uint64_t RoundedFEnd = llvm::alignTo(FEndInBits, Ctx.getCharWidth());
120 
121     // Set Start if this is the first field of a sequence of trivial fields.
122     if (Start == End)
123       Start = CurStructOffset + Ctx.toCharUnitsFromBits(FStartInBits);
124     End = CurStructOffset + Ctx.toCharUnitsFromBits(RoundedFEnd);
125   }
126 
127   CharUnits Start = CharUnits::Zero(), End = CharUnits::Zero();
128 };
129 
130 // This function creates the mangled name of a special function of a non-trivial
131 // C struct. Since there is no ODR in C, the function is mangled based on the
132 // struct contents and not the name. The mangled name has the following
133 // structure:
134 //
135 // <function-name> ::= <prefix> <alignment-info> "_" <struct-field-info>
136 // <prefix> ::= "__destructor_" | "__default_constructor_" |
137 //              "__copy_constructor_" | "__move_constructor_" |
138 //              "__copy_assignment_" | "__move_assignment_"
139 // <alignment-info> ::= <dst-alignment> ["_" <src-alignment>]
140 // <struct-field-info> ::= <field-info>+
141 // <field-info> ::= <struct-or-scalar-field-info> | <array-field-info>
142 // <struct-or-scalar-field-info> ::= "_S" <struct-field-info> |
143 //                                   <strong-field-info> | <trivial-field-info>
144 // <array-field-info> ::= "_AB" <array-offset> "s" <element-size> "n"
145 //                        <num-elements> <innermost-element-info> "_AE"
146 // <innermost-element-info> ::= <struct-or-scalar-field-info>
147 // <strong-field-info> ::= "_s" ["b"] ["v"] <field-offset>
148 // <trivial-field-info> ::= "_t" ["v"] <field-offset> "_" <field-size>
149 
150 template <class Derived> struct GenFuncNameBase {
151   std::string getVolatileOffsetStr(bool IsVolatile, CharUnits Offset) {
152     std::string S;
153     if (IsVolatile)
154       S = "v";
155     S += llvm::to_string(Offset.getQuantity());
156     return S;
157   }
158 
159   void visitARCStrong(QualType FT, const FieldDecl *FD,
160                       CharUnits CurStructOffset) {
161     appendStr("_s");
162     if (FT->isBlockPointerType())
163       appendStr("b");
164     CharUnits FieldOffset = CurStructOffset + asDerived().getFieldOffset(FD);
165     appendStr(getVolatileOffsetStr(FT.isVolatileQualified(), FieldOffset));
166   }
167 
168   void visitARCWeak(QualType FT, const FieldDecl *FD,
169                     CharUnits CurStructOffset) {
170     appendStr("_w");
171     CharUnits FieldOffset = CurStructOffset + asDerived().getFieldOffset(FD);
172     appendStr(getVolatileOffsetStr(FT.isVolatileQualified(), FieldOffset));
173   }
174 
175   void visitStruct(QualType QT, const FieldDecl *FD,
176                    CharUnits CurStructOffset) {
177     CharUnits FieldOffset = CurStructOffset + asDerived().getFieldOffset(FD);
178     appendStr("_S");
179     asDerived().visitStructFields(QT, FieldOffset);
180   }
181 
182   template <class FieldKind>
183   void visitArray(FieldKind FK, const ArrayType *AT, bool IsVolatile,
184                   const FieldDecl *FD, CharUnits CurStructOffset) {
185     // String for non-volatile trivial fields is emitted when
186     // flushTrivialFields is called.
187     if (!FK)
188       return asDerived().visitTrivial(QualType(AT, 0), FD, CurStructOffset);
189 
190     asDerived().flushTrivialFields();
191     CharUnits FieldOffset = CurStructOffset + asDerived().getFieldOffset(FD);
192     ASTContext &Ctx = asDerived().getContext();
193     const ConstantArrayType *CAT = cast<ConstantArrayType>(AT);
194     unsigned NumElts = Ctx.getConstantArrayElementCount(CAT);
195     QualType EltTy = Ctx.getBaseElementType(CAT);
196     CharUnits EltSize = Ctx.getTypeSizeInChars(EltTy);
197     appendStr("_AB" + llvm::to_string(FieldOffset.getQuantity()) + "s" +
198               llvm::to_string(EltSize.getQuantity()) + "n" +
199               llvm::to_string(NumElts));
200     EltTy = IsVolatile ? EltTy.withVolatile() : EltTy;
201     asDerived().visitWithKind(FK, EltTy, nullptr, FieldOffset);
202     appendStr("_AE");
203   }
204 
205   void appendStr(StringRef Str) { Name += Str; }
206 
207   std::string getName(QualType QT, bool IsVolatile) {
208     QT = IsVolatile ? QT.withVolatile() : QT;
209     asDerived().visitStructFields(QT, CharUnits::Zero());
210     return Name;
211   }
212 
213   Derived &asDerived() { return static_cast<Derived &>(*this); }
214 
215   std::string Name;
216 };
217 
218 template <class Derived>
219 struct GenUnaryFuncName : StructVisitor<Derived>, GenFuncNameBase<Derived> {
220   GenUnaryFuncName(StringRef Prefix, CharUnits DstAlignment, ASTContext &Ctx)
221       : StructVisitor<Derived>(Ctx) {
222     this->appendStr(Prefix);
223     this->appendStr(llvm::to_string(DstAlignment.getQuantity()));
224   }
225 };
226 
227 // Helper function to create a null constant.
228 static llvm::Constant *getNullForVariable(Address Addr) {
229   llvm::Type *Ty = Addr.getElementType();
230   return llvm::ConstantPointerNull::get(cast<llvm::PointerType>(Ty));
231 }
232 
233 template <bool IsMove>
234 struct GenBinaryFuncName : CopyStructVisitor<GenBinaryFuncName<IsMove>, IsMove>,
235                            GenFuncNameBase<GenBinaryFuncName<IsMove>> {
236 
237   GenBinaryFuncName(StringRef Prefix, CharUnits DstAlignment,
238                     CharUnits SrcAlignment, ASTContext &Ctx)
239       : CopyStructVisitor<GenBinaryFuncName<IsMove>, IsMove>(Ctx) {
240     this->appendStr(Prefix);
241     this->appendStr(llvm::to_string(DstAlignment.getQuantity()));
242     this->appendStr("_" + llvm::to_string(SrcAlignment.getQuantity()));
243   }
244 
245   void flushTrivialFields() {
246     if (this->Start == this->End)
247       return;
248 
249     this->appendStr("_t" + llvm::to_string(this->Start.getQuantity()) + "w" +
250                     llvm::to_string((this->End - this->Start).getQuantity()));
251 
252     this->Start = this->End = CharUnits::Zero();
253   }
254 
255   void visitVolatileTrivial(QualType FT, const FieldDecl *FD,
256                             CharUnits CurStructOffset) {
257     // Zero-length bit-fields don't need to be copied/assigned.
258     if (FD && FD->isZeroLengthBitField(this->Ctx))
259       return;
260 
261     // Because volatile fields can be bit-fields and are individually copied,
262     // their offset and width are in bits.
263     uint64_t OffsetInBits =
264         this->Ctx.toBits(CurStructOffset) + this->getFieldOffsetInBits(FD);
265     this->appendStr("_tv" + llvm::to_string(OffsetInBits) + "w" +
266                     llvm::to_string(getFieldSize(FD, FT, this->Ctx)));
267   }
268 };
269 
270 struct GenDefaultInitializeFuncName
271     : GenUnaryFuncName<GenDefaultInitializeFuncName>,
272       DefaultInitializedTypeVisitor<GenDefaultInitializeFuncName> {
273   using Super = DefaultInitializedTypeVisitor<GenDefaultInitializeFuncName>;
274   GenDefaultInitializeFuncName(CharUnits DstAlignment, ASTContext &Ctx)
275       : GenUnaryFuncName<GenDefaultInitializeFuncName>("__default_constructor_",
276                                                        DstAlignment, Ctx) {}
277   void visitWithKind(QualType::PrimitiveDefaultInitializeKind PDIK, QualType FT,
278                      const FieldDecl *FD, CharUnits CurStructOffset) {
279     if (const auto *AT = getContext().getAsArrayType(FT)) {
280       visitArray(PDIK, AT, FT.isVolatileQualified(), FD, CurStructOffset);
281       return;
282     }
283 
284     Super::visitWithKind(PDIK, FT, FD, CurStructOffset);
285   }
286 };
287 
288 struct GenDestructorFuncName : GenUnaryFuncName<GenDestructorFuncName>,
289                                DestructedTypeVisitor<GenDestructorFuncName> {
290   using Super = DestructedTypeVisitor<GenDestructorFuncName>;
291   GenDestructorFuncName(const char *Prefix, CharUnits DstAlignment,
292                         ASTContext &Ctx)
293       : GenUnaryFuncName<GenDestructorFuncName>(Prefix, DstAlignment, Ctx) {}
294   void visitWithKind(QualType::DestructionKind DK, QualType FT,
295                      const FieldDecl *FD, CharUnits CurStructOffset) {
296     if (const auto *AT = getContext().getAsArrayType(FT)) {
297       visitArray(DK, AT, FT.isVolatileQualified(), FD, CurStructOffset);
298       return;
299     }
300 
301     Super::visitWithKind(DK, FT, FD, CurStructOffset);
302   }
303 };
304 
305 // Helper function that creates CGFunctionInfo for an N-ary special function.
306 template <size_t N>
307 static const CGFunctionInfo &getFunctionInfo(CodeGenModule &CGM,
308                                              FunctionArgList &Args) {
309   ASTContext &Ctx = CGM.getContext();
310   llvm::SmallVector<ImplicitParamDecl *, N> Params;
311   QualType ParamTy = Ctx.getPointerType(Ctx.VoidPtrTy);
312 
313   for (unsigned I = 0; I < N; ++I)
314     Params.push_back(ImplicitParamDecl::Create(
315         Ctx, nullptr, SourceLocation(), &Ctx.Idents.get(ValNameStr[I]), ParamTy,
316         ImplicitParamDecl::Other));
317 
318   llvm::append_range(Args, Params);
319 
320   return CGM.getTypes().arrangeBuiltinFunctionDeclaration(Ctx.VoidTy, Args);
321 }
322 
323 template <size_t N, size_t... Ints>
324 static std::array<Address, N> getParamAddrs(std::index_sequence<Ints...> IntSeq,
325                                             std::array<CharUnits, N> Alignments,
326                                             const FunctionArgList &Args,
327                                             CodeGenFunction *CGF) {
328   return std::array<Address, N>{
329       {Address(CGF->Builder.CreateLoad(CGF->GetAddrOfLocalVar(Args[Ints])),
330                CGF->VoidPtrTy, Alignments[Ints], KnownNonNull)...}};
331 }
332 
333 // Template classes that are used as bases for classes that emit special
334 // functions.
335 template <class Derived> struct GenFuncBase {
336   template <size_t N>
337   void visitStruct(QualType FT, const FieldDecl *FD, CharUnits CurStructOffset,
338                    std::array<Address, N> Addrs) {
339     this->asDerived().callSpecialFunction(
340         FT, CurStructOffset + asDerived().getFieldOffset(FD), Addrs);
341   }
342 
343   template <class FieldKind, size_t N>
344   void visitArray(FieldKind FK, const ArrayType *AT, bool IsVolatile,
345                   const FieldDecl *FD, CharUnits CurStructOffset,
346                   std::array<Address, N> Addrs) {
347     // Non-volatile trivial fields are copied when flushTrivialFields is called.
348     if (!FK)
349       return asDerived().visitTrivial(QualType(AT, 0), FD, CurStructOffset,
350                                       Addrs);
351 
352     asDerived().flushTrivialFields(Addrs);
353     CodeGenFunction &CGF = *this->CGF;
354     ASTContext &Ctx = CGF.getContext();
355 
356     // Compute the end address.
357     QualType BaseEltQT;
358     std::array<Address, N> StartAddrs = Addrs;
359     for (unsigned I = 0; I < N; ++I)
360       StartAddrs[I] = getAddrWithOffset(Addrs[I], CurStructOffset, FD);
361     Address DstAddr = StartAddrs[DstIdx];
362     llvm::Value *NumElts = CGF.emitArrayLength(AT, BaseEltQT, DstAddr);
363     unsigned BaseEltSize = Ctx.getTypeSizeInChars(BaseEltQT).getQuantity();
364     llvm::Value *BaseEltSizeVal =
365         llvm::ConstantInt::get(NumElts->getType(), BaseEltSize);
366     llvm::Value *SizeInBytes =
367         CGF.Builder.CreateNUWMul(BaseEltSizeVal, NumElts);
368     llvm::Value *DstArrayEnd = CGF.Builder.CreateInBoundsGEP(
369         CGF.Int8Ty, DstAddr.getPointer(), SizeInBytes);
370     DstArrayEnd = CGF.Builder.CreateBitCast(
371         DstArrayEnd, CGF.CGM.Int8PtrPtrTy, "dstarray.end");
372     llvm::BasicBlock *PreheaderBB = CGF.Builder.GetInsertBlock();
373 
374     // Create the header block and insert the phi instructions.
375     llvm::BasicBlock *HeaderBB = CGF.createBasicBlock("loop.header");
376     CGF.EmitBlock(HeaderBB);
377     llvm::PHINode *PHIs[N];
378 
379     for (unsigned I = 0; I < N; ++I) {
380       PHIs[I] = CGF.Builder.CreatePHI(CGF.CGM.Int8PtrPtrTy, 2, "addr.cur");
381       PHIs[I]->addIncoming(StartAddrs[I].getPointer(), PreheaderBB);
382     }
383 
384     // Create the exit and loop body blocks.
385     llvm::BasicBlock *ExitBB = CGF.createBasicBlock("loop.exit");
386     llvm::BasicBlock *LoopBB = CGF.createBasicBlock("loop.body");
387 
388     // Emit the comparison and conditional branch instruction that jumps to
389     // either the exit or the loop body.
390     llvm::Value *Done =
391         CGF.Builder.CreateICmpEQ(PHIs[DstIdx], DstArrayEnd, "done");
392     CGF.Builder.CreateCondBr(Done, ExitBB, LoopBB);
393 
394     // Visit the element of the array in the loop body.
395     CGF.EmitBlock(LoopBB);
396     QualType EltQT = AT->getElementType();
397     CharUnits EltSize = Ctx.getTypeSizeInChars(EltQT);
398     std::array<Address, N> NewAddrs = Addrs;
399 
400     for (unsigned I = 0; I < N; ++I)
401       NewAddrs[I] =
402             Address(PHIs[I], CGF.Int8PtrTy,
403                     StartAddrs[I].getAlignment().alignmentAtOffset(EltSize));
404 
405     EltQT = IsVolatile ? EltQT.withVolatile() : EltQT;
406     this->asDerived().visitWithKind(FK, EltQT, nullptr, CharUnits::Zero(),
407                                     NewAddrs);
408 
409     LoopBB = CGF.Builder.GetInsertBlock();
410 
411     for (unsigned I = 0; I < N; ++I) {
412       // Instrs to update the destination and source addresses.
413       // Update phi instructions.
414       NewAddrs[I] = getAddrWithOffset(NewAddrs[I], EltSize);
415       PHIs[I]->addIncoming(NewAddrs[I].getPointer(), LoopBB);
416     }
417 
418     // Insert an unconditional branch to the header block.
419     CGF.Builder.CreateBr(HeaderBB);
420     CGF.EmitBlock(ExitBB);
421   }
422 
423   /// Return an address with the specified offset from the passed address.
424   Address getAddrWithOffset(Address Addr, CharUnits Offset) {
425     assert(Addr.isValid() && "invalid address");
426     if (Offset.getQuantity() == 0)
427       return Addr;
428     Addr = Addr.withElementType(CGF->CGM.Int8Ty);
429     Addr = CGF->Builder.CreateConstInBoundsGEP(Addr, Offset.getQuantity());
430     return Addr.withElementType(CGF->CGM.Int8PtrTy);
431   }
432 
433   Address getAddrWithOffset(Address Addr, CharUnits StructFieldOffset,
434                             const FieldDecl *FD) {
435     return getAddrWithOffset(Addr, StructFieldOffset +
436                                        asDerived().getFieldOffset(FD));
437   }
438 
439   template <size_t N>
440   llvm::Function *getFunction(StringRef FuncName, QualType QT,
441                               std::array<CharUnits, N> Alignments,
442                               CodeGenModule &CGM) {
443     // If the special function already exists in the module, return it.
444     if (llvm::Function *F = CGM.getModule().getFunction(FuncName)) {
445       bool WrongType = false;
446       if (!F->getReturnType()->isVoidTy())
447         WrongType = true;
448       else {
449         for (const llvm::Argument &Arg : F->args())
450           if (Arg.getType() != CGM.Int8PtrPtrTy)
451             WrongType = true;
452       }
453 
454       if (WrongType) {
455         std::string FuncName = std::string(F->getName());
456         SourceLocation Loc = QT->castAs<RecordType>()->getDecl()->getLocation();
457         CGM.Error(Loc, "special function " + FuncName +
458                            " for non-trivial C struct has incorrect type");
459         return nullptr;
460       }
461       return F;
462     }
463 
464     ASTContext &Ctx = CGM.getContext();
465     FunctionArgList Args;
466     const CGFunctionInfo &FI = getFunctionInfo<N>(CGM, Args);
467     llvm::FunctionType *FuncTy = CGM.getTypes().GetFunctionType(FI);
468     llvm::Function *F =
469         llvm::Function::Create(FuncTy, llvm::GlobalValue::LinkOnceODRLinkage,
470                                FuncName, &CGM.getModule());
471     F->setVisibility(llvm::GlobalValue::HiddenVisibility);
472     CGM.SetLLVMFunctionAttributes(GlobalDecl(), FI, F, /*IsThunk=*/false);
473     CGM.SetLLVMFunctionAttributesForDefinition(nullptr, F);
474     CodeGenFunction NewCGF(CGM);
475     setCGF(&NewCGF);
476     CGF->StartFunction(GlobalDecl(), Ctx.VoidTy, F, FI, Args);
477     auto AL = ApplyDebugLocation::CreateArtificial(*CGF);
478     std::array<Address, N> Addrs =
479         getParamAddrs<N>(std::make_index_sequence<N>{}, Alignments, Args, CGF);
480     asDerived().visitStructFields(QT, CharUnits::Zero(), Addrs);
481     CGF->FinishFunction();
482     return F;
483   }
484 
485   template <size_t N>
486   void callFunc(StringRef FuncName, QualType QT, std::array<Address, N> Addrs,
487                 CodeGenFunction &CallerCGF) {
488     std::array<CharUnits, N> Alignments;
489     llvm::Value *Ptrs[N];
490 
491     for (unsigned I = 0; I < N; ++I) {
492       Alignments[I] = Addrs[I].getAlignment();
493       Ptrs[I] = Addrs[I].getPointer();
494     }
495 
496     if (llvm::Function *F =
497             getFunction(FuncName, QT, Alignments, CallerCGF.CGM))
498       CallerCGF.EmitNounwindRuntimeCall(F, Ptrs);
499   }
500 
501   Derived &asDerived() { return static_cast<Derived &>(*this); }
502 
503   void setCGF(CodeGenFunction *F) { CGF = F; }
504 
505   CodeGenFunction *CGF = nullptr;
506 };
507 
508 template <class Derived, bool IsMove>
509 struct GenBinaryFunc : CopyStructVisitor<Derived, IsMove>,
510                        GenFuncBase<Derived> {
511   GenBinaryFunc(ASTContext &Ctx) : CopyStructVisitor<Derived, IsMove>(Ctx) {}
512 
513   void flushTrivialFields(std::array<Address, 2> Addrs) {
514     CharUnits Size = this->End - this->Start;
515 
516     if (Size.getQuantity() == 0)
517       return;
518 
519     Address DstAddr = this->getAddrWithOffset(Addrs[DstIdx], this->Start);
520     Address SrcAddr = this->getAddrWithOffset(Addrs[SrcIdx], this->Start);
521 
522     // Emit memcpy.
523     if (Size.getQuantity() >= 16 ||
524         !llvm::has_single_bit<uint32_t>(Size.getQuantity())) {
525       llvm::Value *SizeVal =
526           llvm::ConstantInt::get(this->CGF->SizeTy, Size.getQuantity());
527       DstAddr = DstAddr.withElementType(this->CGF->Int8Ty);
528       SrcAddr = SrcAddr.withElementType(this->CGF->Int8Ty);
529       this->CGF->Builder.CreateMemCpy(DstAddr, SrcAddr, SizeVal, false);
530     } else {
531       llvm::Type *Ty = llvm::Type::getIntNTy(
532           this->CGF->getLLVMContext(),
533           Size.getQuantity() * this->CGF->getContext().getCharWidth());
534       DstAddr = DstAddr.withElementType(Ty);
535       SrcAddr = SrcAddr.withElementType(Ty);
536       llvm::Value *SrcVal = this->CGF->Builder.CreateLoad(SrcAddr, false);
537       this->CGF->Builder.CreateStore(SrcVal, DstAddr, false);
538     }
539 
540     this->Start = this->End = CharUnits::Zero();
541   }
542 
543   template <class... Ts>
544   void visitVolatileTrivial(QualType FT, const FieldDecl *FD, CharUnits Offset,
545                             std::array<Address, 2> Addrs) {
546     LValue DstLV, SrcLV;
547     if (FD) {
548       // No need to copy zero-length bit-fields.
549       if (FD->isZeroLengthBitField(this->CGF->getContext()))
550         return;
551 
552       QualType RT = QualType(FD->getParent()->getTypeForDecl(), 0);
553       llvm::Type *Ty = this->CGF->ConvertType(RT);
554       Address DstAddr = this->getAddrWithOffset(Addrs[DstIdx], Offset);
555       LValue DstBase =
556           this->CGF->MakeAddrLValue(DstAddr.withElementType(Ty), FT);
557       DstLV = this->CGF->EmitLValueForField(DstBase, FD);
558       Address SrcAddr = this->getAddrWithOffset(Addrs[SrcIdx], Offset);
559       LValue SrcBase =
560           this->CGF->MakeAddrLValue(SrcAddr.withElementType(Ty), FT);
561       SrcLV = this->CGF->EmitLValueForField(SrcBase, FD);
562     } else {
563       llvm::Type *Ty = this->CGF->ConvertTypeForMem(FT);
564       Address DstAddr = Addrs[DstIdx].withElementType(Ty);
565       Address SrcAddr = Addrs[SrcIdx].withElementType(Ty);
566       DstLV = this->CGF->MakeAddrLValue(DstAddr, FT);
567       SrcLV = this->CGF->MakeAddrLValue(SrcAddr, FT);
568     }
569     RValue SrcVal = this->CGF->EmitLoadOfLValue(SrcLV, SourceLocation());
570     this->CGF->EmitStoreThroughLValue(SrcVal, DstLV);
571   }
572 };
573 
574 // These classes that emit the special functions for a non-trivial struct.
575 struct GenDestructor : StructVisitor<GenDestructor>,
576                        GenFuncBase<GenDestructor>,
577                        DestructedTypeVisitor<GenDestructor> {
578   using Super = DestructedTypeVisitor<GenDestructor>;
579   GenDestructor(ASTContext &Ctx) : StructVisitor<GenDestructor>(Ctx) {}
580 
581   void visitWithKind(QualType::DestructionKind DK, QualType FT,
582                      const FieldDecl *FD, CharUnits CurStructOffset,
583                      std::array<Address, 1> Addrs) {
584     if (const auto *AT = getContext().getAsArrayType(FT)) {
585       visitArray(DK, AT, FT.isVolatileQualified(), FD, CurStructOffset, Addrs);
586       return;
587     }
588 
589     Super::visitWithKind(DK, FT, FD, CurStructOffset, Addrs);
590   }
591 
592   void visitARCStrong(QualType QT, const FieldDecl *FD,
593                       CharUnits CurStructOffset, std::array<Address, 1> Addrs) {
594     CGF->destroyARCStrongImprecise(
595         *CGF, getAddrWithOffset(Addrs[DstIdx], CurStructOffset, FD), QT);
596   }
597 
598   void visitARCWeak(QualType QT, const FieldDecl *FD, CharUnits CurStructOffset,
599                     std::array<Address, 1> Addrs) {
600     CGF->destroyARCWeak(
601         *CGF, getAddrWithOffset(Addrs[DstIdx], CurStructOffset, FD), QT);
602   }
603 
604   void callSpecialFunction(QualType FT, CharUnits Offset,
605                            std::array<Address, 1> Addrs) {
606     CGF->callCStructDestructor(
607         CGF->MakeAddrLValue(getAddrWithOffset(Addrs[DstIdx], Offset), FT));
608   }
609 };
610 
611 struct GenDefaultInitialize
612     : StructVisitor<GenDefaultInitialize>,
613       GenFuncBase<GenDefaultInitialize>,
614       DefaultInitializedTypeVisitor<GenDefaultInitialize> {
615   using Super = DefaultInitializedTypeVisitor<GenDefaultInitialize>;
616   typedef GenFuncBase<GenDefaultInitialize> GenFuncBaseTy;
617 
618   GenDefaultInitialize(ASTContext &Ctx)
619       : StructVisitor<GenDefaultInitialize>(Ctx) {}
620 
621   void visitWithKind(QualType::PrimitiveDefaultInitializeKind PDIK, QualType FT,
622                      const FieldDecl *FD, CharUnits CurStructOffset,
623                      std::array<Address, 1> Addrs) {
624     if (const auto *AT = getContext().getAsArrayType(FT)) {
625       visitArray(PDIK, AT, FT.isVolatileQualified(), FD, CurStructOffset,
626                  Addrs);
627       return;
628     }
629 
630     Super::visitWithKind(PDIK, FT, FD, CurStructOffset, Addrs);
631   }
632 
633   void visitARCStrong(QualType QT, const FieldDecl *FD,
634                       CharUnits CurStructOffset, std::array<Address, 1> Addrs) {
635     CGF->EmitNullInitialization(
636         getAddrWithOffset(Addrs[DstIdx], CurStructOffset, FD), QT);
637   }
638 
639   void visitARCWeak(QualType QT, const FieldDecl *FD, CharUnits CurStructOffset,
640                     std::array<Address, 1> Addrs) {
641     CGF->EmitNullInitialization(
642         getAddrWithOffset(Addrs[DstIdx], CurStructOffset, FD), QT);
643   }
644 
645   template <class FieldKind, size_t... Is>
646   void visitArray(FieldKind FK, const ArrayType *AT, bool IsVolatile,
647                   const FieldDecl *FD, CharUnits CurStructOffset,
648                   std::array<Address, 1> Addrs) {
649     if (!FK)
650       return visitTrivial(QualType(AT, 0), FD, CurStructOffset, Addrs);
651 
652     ASTContext &Ctx = getContext();
653     CharUnits Size = Ctx.getTypeSizeInChars(QualType(AT, 0));
654     QualType EltTy = Ctx.getBaseElementType(QualType(AT, 0));
655 
656     if (Size < CharUnits::fromQuantity(16) || EltTy->getAs<RecordType>()) {
657       GenFuncBaseTy::visitArray(FK, AT, IsVolatile, FD, CurStructOffset, Addrs);
658       return;
659     }
660 
661     llvm::Constant *SizeVal = CGF->Builder.getInt64(Size.getQuantity());
662     Address DstAddr = getAddrWithOffset(Addrs[DstIdx], CurStructOffset, FD);
663     Address Loc = DstAddr.withElementType(CGF->Int8Ty);
664     CGF->Builder.CreateMemSet(Loc, CGF->Builder.getInt8(0), SizeVal,
665                               IsVolatile);
666   }
667 
668   void callSpecialFunction(QualType FT, CharUnits Offset,
669                            std::array<Address, 1> Addrs) {
670     CGF->callCStructDefaultConstructor(
671         CGF->MakeAddrLValue(getAddrWithOffset(Addrs[DstIdx], Offset), FT));
672   }
673 };
674 
675 struct GenCopyConstructor : GenBinaryFunc<GenCopyConstructor, false> {
676   GenCopyConstructor(ASTContext &Ctx)
677       : GenBinaryFunc<GenCopyConstructor, false>(Ctx) {}
678 
679   void visitARCStrong(QualType QT, const FieldDecl *FD,
680                       CharUnits CurStructOffset, std::array<Address, 2> Addrs) {
681     Addrs[DstIdx] = getAddrWithOffset(Addrs[DstIdx], CurStructOffset, FD);
682     Addrs[SrcIdx] = getAddrWithOffset(Addrs[SrcIdx], CurStructOffset, FD);
683     llvm::Value *SrcVal = CGF->EmitLoadOfScalar(
684         Addrs[SrcIdx], QT.isVolatileQualified(), QT, SourceLocation());
685     llvm::Value *Val = CGF->EmitARCRetain(QT, SrcVal);
686     CGF->EmitStoreOfScalar(Val, CGF->MakeAddrLValue(Addrs[DstIdx], QT), true);
687   }
688 
689   void visitARCWeak(QualType QT, const FieldDecl *FD, CharUnits CurStructOffset,
690                     std::array<Address, 2> Addrs) {
691     Addrs[DstIdx] = getAddrWithOffset(Addrs[DstIdx], CurStructOffset, FD);
692     Addrs[SrcIdx] = getAddrWithOffset(Addrs[SrcIdx], CurStructOffset, FD);
693     CGF->EmitARCCopyWeak(Addrs[DstIdx], Addrs[SrcIdx]);
694   }
695 
696   void callSpecialFunction(QualType FT, CharUnits Offset,
697                            std::array<Address, 2> Addrs) {
698     Addrs[DstIdx] = getAddrWithOffset(Addrs[DstIdx], Offset);
699     Addrs[SrcIdx] = getAddrWithOffset(Addrs[SrcIdx], Offset);
700     CGF->callCStructCopyConstructor(CGF->MakeAddrLValue(Addrs[DstIdx], FT),
701                                     CGF->MakeAddrLValue(Addrs[SrcIdx], FT));
702   }
703 };
704 
705 struct GenMoveConstructor : GenBinaryFunc<GenMoveConstructor, true> {
706   GenMoveConstructor(ASTContext &Ctx)
707       : GenBinaryFunc<GenMoveConstructor, true>(Ctx) {}
708 
709   void visitARCStrong(QualType QT, const FieldDecl *FD,
710                       CharUnits CurStructOffset, std::array<Address, 2> Addrs) {
711     Addrs[DstIdx] = getAddrWithOffset(Addrs[DstIdx], CurStructOffset, FD);
712     Addrs[SrcIdx] = getAddrWithOffset(Addrs[SrcIdx], CurStructOffset, FD);
713     LValue SrcLV = CGF->MakeAddrLValue(Addrs[SrcIdx], QT);
714     llvm::Value *SrcVal =
715         CGF->EmitLoadOfLValue(SrcLV, SourceLocation()).getScalarVal();
716     CGF->EmitStoreOfScalar(getNullForVariable(SrcLV.getAddress(*CGF)), SrcLV);
717     CGF->EmitStoreOfScalar(SrcVal, CGF->MakeAddrLValue(Addrs[DstIdx], QT),
718                            /* isInitialization */ true);
719   }
720 
721   void visitARCWeak(QualType QT, const FieldDecl *FD, CharUnits CurStructOffset,
722                     std::array<Address, 2> Addrs) {
723     Addrs[DstIdx] = getAddrWithOffset(Addrs[DstIdx], CurStructOffset, FD);
724     Addrs[SrcIdx] = getAddrWithOffset(Addrs[SrcIdx], CurStructOffset, FD);
725     CGF->EmitARCMoveWeak(Addrs[DstIdx], Addrs[SrcIdx]);
726   }
727 
728   void callSpecialFunction(QualType FT, CharUnits Offset,
729                            std::array<Address, 2> Addrs) {
730     Addrs[DstIdx] = getAddrWithOffset(Addrs[DstIdx], Offset);
731     Addrs[SrcIdx] = getAddrWithOffset(Addrs[SrcIdx], Offset);
732     CGF->callCStructMoveConstructor(CGF->MakeAddrLValue(Addrs[DstIdx], FT),
733                                     CGF->MakeAddrLValue(Addrs[SrcIdx], FT));
734   }
735 };
736 
737 struct GenCopyAssignment : GenBinaryFunc<GenCopyAssignment, false> {
738   GenCopyAssignment(ASTContext &Ctx)
739       : GenBinaryFunc<GenCopyAssignment, false>(Ctx) {}
740 
741   void visitARCStrong(QualType QT, const FieldDecl *FD,
742                       CharUnits CurStructOffset, std::array<Address, 2> Addrs) {
743     Addrs[DstIdx] = getAddrWithOffset(Addrs[DstIdx], CurStructOffset, FD);
744     Addrs[SrcIdx] = getAddrWithOffset(Addrs[SrcIdx], CurStructOffset, FD);
745     llvm::Value *SrcVal = CGF->EmitLoadOfScalar(
746         Addrs[SrcIdx], QT.isVolatileQualified(), QT, SourceLocation());
747     CGF->EmitARCStoreStrong(CGF->MakeAddrLValue(Addrs[DstIdx], QT), SrcVal,
748                             false);
749   }
750 
751   void visitARCWeak(QualType QT, const FieldDecl *FD, CharUnits CurStructOffset,
752                     std::array<Address, 2> Addrs) {
753     Addrs[DstIdx] = getAddrWithOffset(Addrs[DstIdx], CurStructOffset, FD);
754     Addrs[SrcIdx] = getAddrWithOffset(Addrs[SrcIdx], CurStructOffset, FD);
755     CGF->emitARCCopyAssignWeak(QT, Addrs[DstIdx], Addrs[SrcIdx]);
756   }
757 
758   void callSpecialFunction(QualType FT, CharUnits Offset,
759                            std::array<Address, 2> Addrs) {
760     Addrs[DstIdx] = getAddrWithOffset(Addrs[DstIdx], Offset);
761     Addrs[SrcIdx] = getAddrWithOffset(Addrs[SrcIdx], Offset);
762     CGF->callCStructCopyAssignmentOperator(
763         CGF->MakeAddrLValue(Addrs[DstIdx], FT),
764         CGF->MakeAddrLValue(Addrs[SrcIdx], FT));
765   }
766 };
767 
768 struct GenMoveAssignment : GenBinaryFunc<GenMoveAssignment, true> {
769   GenMoveAssignment(ASTContext &Ctx)
770       : GenBinaryFunc<GenMoveAssignment, true>(Ctx) {}
771 
772   void visitARCStrong(QualType QT, const FieldDecl *FD,
773                       CharUnits CurStructOffset, std::array<Address, 2> Addrs) {
774     Addrs[DstIdx] = getAddrWithOffset(Addrs[DstIdx], CurStructOffset, FD);
775     Addrs[SrcIdx] = getAddrWithOffset(Addrs[SrcIdx], CurStructOffset, FD);
776     LValue SrcLV = CGF->MakeAddrLValue(Addrs[SrcIdx], QT);
777     llvm::Value *SrcVal =
778         CGF->EmitLoadOfLValue(SrcLV, SourceLocation()).getScalarVal();
779     CGF->EmitStoreOfScalar(getNullForVariable(SrcLV.getAddress(*CGF)), SrcLV);
780     LValue DstLV = CGF->MakeAddrLValue(Addrs[DstIdx], QT);
781     llvm::Value *DstVal =
782         CGF->EmitLoadOfLValue(DstLV, SourceLocation()).getScalarVal();
783     CGF->EmitStoreOfScalar(SrcVal, DstLV);
784     CGF->EmitARCRelease(DstVal, ARCImpreciseLifetime);
785   }
786 
787   void visitARCWeak(QualType QT, const FieldDecl *FD, CharUnits CurStructOffset,
788                     std::array<Address, 2> Addrs) {
789     Addrs[DstIdx] = getAddrWithOffset(Addrs[DstIdx], CurStructOffset, FD);
790     Addrs[SrcIdx] = getAddrWithOffset(Addrs[SrcIdx], CurStructOffset, FD);
791     CGF->emitARCMoveAssignWeak(QT, Addrs[DstIdx], Addrs[SrcIdx]);
792   }
793 
794   void callSpecialFunction(QualType FT, CharUnits Offset,
795                            std::array<Address, 2> Addrs) {
796     Addrs[DstIdx] = getAddrWithOffset(Addrs[DstIdx], Offset);
797     Addrs[SrcIdx] = getAddrWithOffset(Addrs[SrcIdx], Offset);
798     CGF->callCStructMoveAssignmentOperator(
799         CGF->MakeAddrLValue(Addrs[DstIdx], FT),
800         CGF->MakeAddrLValue(Addrs[SrcIdx], FT));
801   }
802 };
803 
804 } // namespace
805 
806 void CodeGenFunction::destroyNonTrivialCStruct(CodeGenFunction &CGF,
807                                                Address Addr, QualType Type) {
808   CGF.callCStructDestructor(CGF.MakeAddrLValue(Addr, Type));
809 }
810 
811 // Default-initialize a variable that is a non-trivial struct or an array of
812 // such structure.
813 void CodeGenFunction::defaultInitNonTrivialCStructVar(LValue Dst) {
814   GenDefaultInitialize Gen(getContext());
815   Address DstPtr = Dst.getAddress(*this).withElementType(CGM.Int8PtrTy);
816   Gen.setCGF(this);
817   QualType QT = Dst.getType();
818   QT = Dst.isVolatile() ? QT.withVolatile() : QT;
819   Gen.visit(QT, nullptr, CharUnits::Zero(), std::array<Address, 1>({{DstPtr}}));
820 }
821 
822 template <class G, size_t N>
823 static void callSpecialFunction(G &&Gen, StringRef FuncName, QualType QT,
824                                 bool IsVolatile, CodeGenFunction &CGF,
825                                 std::array<Address, N> Addrs) {
826   auto SetArtificialLoc = ApplyDebugLocation::CreateArtificial(CGF);
827   for (unsigned I = 0; I < N; ++I)
828     Addrs[I] = Addrs[I].withElementType(CGF.CGM.Int8PtrTy);
829   QT = IsVolatile ? QT.withVolatile() : QT;
830   Gen.callFunc(FuncName, QT, Addrs, CGF);
831 }
832 
833 template <class G, size_t N>
834 static llvm::Function *
835 getSpecialFunction(G &&Gen, StringRef FuncName, QualType QT, bool IsVolatile,
836                    std::array<CharUnits, N> Alignments, CodeGenModule &CGM) {
837   QT = IsVolatile ? QT.withVolatile() : QT;
838   // The following call requires an array of addresses as arguments, but doesn't
839   // actually use them (it overwrites them with the addresses of the arguments
840   // of the created function).
841   return Gen.getFunction(FuncName, QT, Alignments, CGM);
842 }
843 
844 // Functions to emit calls to the special functions of a non-trivial C struct.
845 void CodeGenFunction::callCStructDefaultConstructor(LValue Dst) {
846   bool IsVolatile = Dst.isVolatile();
847   Address DstPtr = Dst.getAddress(*this);
848   QualType QT = Dst.getType();
849   GenDefaultInitializeFuncName GenName(DstPtr.getAlignment(), getContext());
850   std::string FuncName = GenName.getName(QT, IsVolatile);
851   callSpecialFunction(GenDefaultInitialize(getContext()), FuncName, QT,
852                       IsVolatile, *this, std::array<Address, 1>({{DstPtr}}));
853 }
854 
855 std::string CodeGenFunction::getNonTrivialCopyConstructorStr(
856     QualType QT, CharUnits Alignment, bool IsVolatile, ASTContext &Ctx) {
857   GenBinaryFuncName<false> GenName("", Alignment, Alignment, Ctx);
858   return GenName.getName(QT, IsVolatile);
859 }
860 
861 std::string CodeGenFunction::getNonTrivialDestructorStr(QualType QT,
862                                                         CharUnits Alignment,
863                                                         bool IsVolatile,
864                                                         ASTContext &Ctx) {
865   GenDestructorFuncName GenName("", Alignment, Ctx);
866   return GenName.getName(QT, IsVolatile);
867 }
868 
869 void CodeGenFunction::callCStructDestructor(LValue Dst) {
870   bool IsVolatile = Dst.isVolatile();
871   Address DstPtr = Dst.getAddress(*this);
872   QualType QT = Dst.getType();
873   GenDestructorFuncName GenName("__destructor_", DstPtr.getAlignment(),
874                                 getContext());
875   std::string FuncName = GenName.getName(QT, IsVolatile);
876   callSpecialFunction(GenDestructor(getContext()), FuncName, QT, IsVolatile,
877                       *this, std::array<Address, 1>({{DstPtr}}));
878 }
879 
880 void CodeGenFunction::callCStructCopyConstructor(LValue Dst, LValue Src) {
881   bool IsVolatile = Dst.isVolatile() || Src.isVolatile();
882   Address DstPtr = Dst.getAddress(*this), SrcPtr = Src.getAddress(*this);
883   QualType QT = Dst.getType();
884   GenBinaryFuncName<false> GenName("__copy_constructor_", DstPtr.getAlignment(),
885                                    SrcPtr.getAlignment(), getContext());
886   std::string FuncName = GenName.getName(QT, IsVolatile);
887   callSpecialFunction(GenCopyConstructor(getContext()), FuncName, QT,
888                       IsVolatile, *this,
889                       std::array<Address, 2>({{DstPtr, SrcPtr}}));
890 }
891 
892 void CodeGenFunction::callCStructCopyAssignmentOperator(LValue Dst, LValue Src
893 
894 ) {
895   bool IsVolatile = Dst.isVolatile() || Src.isVolatile();
896   Address DstPtr = Dst.getAddress(*this), SrcPtr = Src.getAddress(*this);
897   QualType QT = Dst.getType();
898   GenBinaryFuncName<false> GenName("__copy_assignment_", DstPtr.getAlignment(),
899                                    SrcPtr.getAlignment(), getContext());
900   std::string FuncName = GenName.getName(QT, IsVolatile);
901   callSpecialFunction(GenCopyAssignment(getContext()), FuncName, QT, IsVolatile,
902                       *this, std::array<Address, 2>({{DstPtr, SrcPtr}}));
903 }
904 
905 void CodeGenFunction::callCStructMoveConstructor(LValue Dst, LValue Src) {
906   bool IsVolatile = Dst.isVolatile() || Src.isVolatile();
907   Address DstPtr = Dst.getAddress(*this), SrcPtr = Src.getAddress(*this);
908   QualType QT = Dst.getType();
909   GenBinaryFuncName<true> GenName("__move_constructor_", DstPtr.getAlignment(),
910                                   SrcPtr.getAlignment(), getContext());
911   std::string FuncName = GenName.getName(QT, IsVolatile);
912   callSpecialFunction(GenMoveConstructor(getContext()), FuncName, QT,
913                       IsVolatile, *this,
914                       std::array<Address, 2>({{DstPtr, SrcPtr}}));
915 }
916 
917 void CodeGenFunction::callCStructMoveAssignmentOperator(LValue Dst, LValue Src
918 
919 ) {
920   bool IsVolatile = Dst.isVolatile() || Src.isVolatile();
921   Address DstPtr = Dst.getAddress(*this), SrcPtr = Src.getAddress(*this);
922   QualType QT = Dst.getType();
923   GenBinaryFuncName<true> GenName("__move_assignment_", DstPtr.getAlignment(),
924                                   SrcPtr.getAlignment(), getContext());
925   std::string FuncName = GenName.getName(QT, IsVolatile);
926   callSpecialFunction(GenMoveAssignment(getContext()), FuncName, QT, IsVolatile,
927                       *this, std::array<Address, 2>({{DstPtr, SrcPtr}}));
928 }
929 
930 llvm::Function *clang::CodeGen::getNonTrivialCStructDefaultConstructor(
931     CodeGenModule &CGM, CharUnits DstAlignment, bool IsVolatile, QualType QT) {
932   ASTContext &Ctx = CGM.getContext();
933   GenDefaultInitializeFuncName GenName(DstAlignment, Ctx);
934   std::string FuncName = GenName.getName(QT, IsVolatile);
935   return getSpecialFunction(GenDefaultInitialize(Ctx), FuncName, QT, IsVolatile,
936                             std::array<CharUnits, 1>({{DstAlignment}}), CGM);
937 }
938 
939 llvm::Function *clang::CodeGen::getNonTrivialCStructCopyConstructor(
940     CodeGenModule &CGM, CharUnits DstAlignment, CharUnits SrcAlignment,
941     bool IsVolatile, QualType QT) {
942   ASTContext &Ctx = CGM.getContext();
943   GenBinaryFuncName<false> GenName("__copy_constructor_", DstAlignment,
944                                    SrcAlignment, Ctx);
945   std::string FuncName = GenName.getName(QT, IsVolatile);
946   return getSpecialFunction(
947       GenCopyConstructor(Ctx), FuncName, QT, IsVolatile,
948       std::array<CharUnits, 2>({{DstAlignment, SrcAlignment}}), CGM);
949 }
950 
951 llvm::Function *clang::CodeGen::getNonTrivialCStructMoveConstructor(
952     CodeGenModule &CGM, CharUnits DstAlignment, CharUnits SrcAlignment,
953     bool IsVolatile, QualType QT) {
954   ASTContext &Ctx = CGM.getContext();
955   GenBinaryFuncName<true> GenName("__move_constructor_", DstAlignment,
956                                   SrcAlignment, Ctx);
957   std::string FuncName = GenName.getName(QT, IsVolatile);
958   return getSpecialFunction(
959       GenMoveConstructor(Ctx), FuncName, QT, IsVolatile,
960       std::array<CharUnits, 2>({{DstAlignment, SrcAlignment}}), CGM);
961 }
962 
963 llvm::Function *clang::CodeGen::getNonTrivialCStructCopyAssignmentOperator(
964     CodeGenModule &CGM, CharUnits DstAlignment, CharUnits SrcAlignment,
965     bool IsVolatile, QualType QT) {
966   ASTContext &Ctx = CGM.getContext();
967   GenBinaryFuncName<false> GenName("__copy_assignment_", DstAlignment,
968                                    SrcAlignment, Ctx);
969   std::string FuncName = GenName.getName(QT, IsVolatile);
970   return getSpecialFunction(
971       GenCopyAssignment(Ctx), FuncName, QT, IsVolatile,
972       std::array<CharUnits, 2>({{DstAlignment, SrcAlignment}}), CGM);
973 }
974 
975 llvm::Function *clang::CodeGen::getNonTrivialCStructMoveAssignmentOperator(
976     CodeGenModule &CGM, CharUnits DstAlignment, CharUnits SrcAlignment,
977     bool IsVolatile, QualType QT) {
978   ASTContext &Ctx = CGM.getContext();
979   GenBinaryFuncName<true> GenName("__move_assignment_", DstAlignment,
980                                   SrcAlignment, Ctx);
981   std::string FuncName = GenName.getName(QT, IsVolatile);
982   return getSpecialFunction(
983       GenMoveAssignment(Ctx), FuncName, QT, IsVolatile,
984       std::array<CharUnits, 2>({{DstAlignment, SrcAlignment}}), CGM);
985 }
986 
987 llvm::Function *clang::CodeGen::getNonTrivialCStructDestructor(
988     CodeGenModule &CGM, CharUnits DstAlignment, bool IsVolatile, QualType QT) {
989   ASTContext &Ctx = CGM.getContext();
990   GenDestructorFuncName GenName("__destructor_", DstAlignment, Ctx);
991   std::string FuncName = GenName.getName(QT, IsVolatile);
992   return getSpecialFunction(GenDestructor(Ctx), FuncName, QT, IsVolatile,
993                             std::array<CharUnits, 1>({{DstAlignment}}), CGM);
994 }
995