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         ImplicitParamKind::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     llvm::BasicBlock *PreheaderBB = CGF.Builder.GetInsertBlock();
371 
372     // Create the header block and insert the phi instructions.
373     llvm::BasicBlock *HeaderBB = CGF.createBasicBlock("loop.header");
374     CGF.EmitBlock(HeaderBB);
375     llvm::PHINode *PHIs[N];
376 
377     for (unsigned I = 0; I < N; ++I) {
378       PHIs[I] = CGF.Builder.CreatePHI(CGF.CGM.Int8PtrPtrTy, 2, "addr.cur");
379       PHIs[I]->addIncoming(StartAddrs[I].getPointer(), PreheaderBB);
380     }
381 
382     // Create the exit and loop body blocks.
383     llvm::BasicBlock *ExitBB = CGF.createBasicBlock("loop.exit");
384     llvm::BasicBlock *LoopBB = CGF.createBasicBlock("loop.body");
385 
386     // Emit the comparison and conditional branch instruction that jumps to
387     // either the exit or the loop body.
388     llvm::Value *Done =
389         CGF.Builder.CreateICmpEQ(PHIs[DstIdx], DstArrayEnd, "done");
390     CGF.Builder.CreateCondBr(Done, ExitBB, LoopBB);
391 
392     // Visit the element of the array in the loop body.
393     CGF.EmitBlock(LoopBB);
394     QualType EltQT = AT->getElementType();
395     CharUnits EltSize = Ctx.getTypeSizeInChars(EltQT);
396     std::array<Address, N> NewAddrs = Addrs;
397 
398     for (unsigned I = 0; I < N; ++I)
399       NewAddrs[I] =
400             Address(PHIs[I], CGF.Int8PtrTy,
401                     StartAddrs[I].getAlignment().alignmentAtOffset(EltSize));
402 
403     EltQT = IsVolatile ? EltQT.withVolatile() : EltQT;
404     this->asDerived().visitWithKind(FK, EltQT, nullptr, CharUnits::Zero(),
405                                     NewAddrs);
406 
407     LoopBB = CGF.Builder.GetInsertBlock();
408 
409     for (unsigned I = 0; I < N; ++I) {
410       // Instrs to update the destination and source addresses.
411       // Update phi instructions.
412       NewAddrs[I] = getAddrWithOffset(NewAddrs[I], EltSize);
413       PHIs[I]->addIncoming(NewAddrs[I].getPointer(), LoopBB);
414     }
415 
416     // Insert an unconditional branch to the header block.
417     CGF.Builder.CreateBr(HeaderBB);
418     CGF.EmitBlock(ExitBB);
419   }
420 
421   /// Return an address with the specified offset from the passed address.
422   Address getAddrWithOffset(Address Addr, CharUnits Offset) {
423     assert(Addr.isValid() && "invalid address");
424     if (Offset.getQuantity() == 0)
425       return Addr;
426     Addr = Addr.withElementType(CGF->CGM.Int8Ty);
427     Addr = CGF->Builder.CreateConstInBoundsGEP(Addr, Offset.getQuantity());
428     return Addr.withElementType(CGF->CGM.Int8PtrTy);
429   }
430 
431   Address getAddrWithOffset(Address Addr, CharUnits StructFieldOffset,
432                             const FieldDecl *FD) {
433     return getAddrWithOffset(Addr, StructFieldOffset +
434                                        asDerived().getFieldOffset(FD));
435   }
436 
437   template <size_t N>
438   llvm::Function *getFunction(StringRef FuncName, QualType QT,
439                               std::array<CharUnits, N> Alignments,
440                               CodeGenModule &CGM) {
441     // If the special function already exists in the module, return it.
442     if (llvm::Function *F = CGM.getModule().getFunction(FuncName)) {
443       bool WrongType = false;
444       if (!F->getReturnType()->isVoidTy())
445         WrongType = true;
446       else {
447         for (const llvm::Argument &Arg : F->args())
448           if (Arg.getType() != CGM.Int8PtrPtrTy)
449             WrongType = true;
450       }
451 
452       if (WrongType) {
453         std::string FuncName = std::string(F->getName());
454         SourceLocation Loc = QT->castAs<RecordType>()->getDecl()->getLocation();
455         CGM.Error(Loc, "special function " + FuncName +
456                            " for non-trivial C struct has incorrect type");
457         return nullptr;
458       }
459       return F;
460     }
461 
462     ASTContext &Ctx = CGM.getContext();
463     FunctionArgList Args;
464     const CGFunctionInfo &FI = getFunctionInfo<N>(CGM, Args);
465     llvm::FunctionType *FuncTy = CGM.getTypes().GetFunctionType(FI);
466     llvm::Function *F =
467         llvm::Function::Create(FuncTy, llvm::GlobalValue::LinkOnceODRLinkage,
468                                FuncName, &CGM.getModule());
469     F->setVisibility(llvm::GlobalValue::HiddenVisibility);
470     CGM.SetLLVMFunctionAttributes(GlobalDecl(), FI, F, /*IsThunk=*/false);
471     CGM.SetLLVMFunctionAttributesForDefinition(nullptr, F);
472     CodeGenFunction NewCGF(CGM);
473     setCGF(&NewCGF);
474     CGF->StartFunction(GlobalDecl(), Ctx.VoidTy, F, FI, Args);
475     auto AL = ApplyDebugLocation::CreateArtificial(*CGF);
476     std::array<Address, N> Addrs =
477         getParamAddrs<N>(std::make_index_sequence<N>{}, Alignments, Args, CGF);
478     asDerived().visitStructFields(QT, CharUnits::Zero(), Addrs);
479     CGF->FinishFunction();
480     return F;
481   }
482 
483   template <size_t N>
484   void callFunc(StringRef FuncName, QualType QT, std::array<Address, N> Addrs,
485                 CodeGenFunction &CallerCGF) {
486     std::array<CharUnits, N> Alignments;
487     llvm::Value *Ptrs[N];
488 
489     for (unsigned I = 0; I < N; ++I) {
490       Alignments[I] = Addrs[I].getAlignment();
491       Ptrs[I] = Addrs[I].getPointer();
492     }
493 
494     if (llvm::Function *F =
495             getFunction(FuncName, QT, Alignments, CallerCGF.CGM))
496       CallerCGF.EmitNounwindRuntimeCall(F, Ptrs);
497   }
498 
499   Derived &asDerived() { return static_cast<Derived &>(*this); }
500 
501   void setCGF(CodeGenFunction *F) { CGF = F; }
502 
503   CodeGenFunction *CGF = nullptr;
504 };
505 
506 template <class Derived, bool IsMove>
507 struct GenBinaryFunc : CopyStructVisitor<Derived, IsMove>,
508                        GenFuncBase<Derived> {
509   GenBinaryFunc(ASTContext &Ctx) : CopyStructVisitor<Derived, IsMove>(Ctx) {}
510 
511   void flushTrivialFields(std::array<Address, 2> Addrs) {
512     CharUnits Size = this->End - this->Start;
513 
514     if (Size.getQuantity() == 0)
515       return;
516 
517     Address DstAddr = this->getAddrWithOffset(Addrs[DstIdx], this->Start);
518     Address SrcAddr = this->getAddrWithOffset(Addrs[SrcIdx], this->Start);
519 
520     // Emit memcpy.
521     if (Size.getQuantity() >= 16 ||
522         !llvm::has_single_bit<uint32_t>(Size.getQuantity())) {
523       llvm::Value *SizeVal =
524           llvm::ConstantInt::get(this->CGF->SizeTy, Size.getQuantity());
525       DstAddr = DstAddr.withElementType(this->CGF->Int8Ty);
526       SrcAddr = SrcAddr.withElementType(this->CGF->Int8Ty);
527       this->CGF->Builder.CreateMemCpy(DstAddr, SrcAddr, SizeVal, false);
528     } else {
529       llvm::Type *Ty = llvm::Type::getIntNTy(
530           this->CGF->getLLVMContext(),
531           Size.getQuantity() * this->CGF->getContext().getCharWidth());
532       DstAddr = DstAddr.withElementType(Ty);
533       SrcAddr = SrcAddr.withElementType(Ty);
534       llvm::Value *SrcVal = this->CGF->Builder.CreateLoad(SrcAddr, false);
535       this->CGF->Builder.CreateStore(SrcVal, DstAddr, false);
536     }
537 
538     this->Start = this->End = CharUnits::Zero();
539   }
540 
541   template <class... Ts>
542   void visitVolatileTrivial(QualType FT, const FieldDecl *FD, CharUnits Offset,
543                             std::array<Address, 2> Addrs) {
544     LValue DstLV, SrcLV;
545     if (FD) {
546       // No need to copy zero-length bit-fields.
547       if (FD->isZeroLengthBitField(this->CGF->getContext()))
548         return;
549 
550       QualType RT = QualType(FD->getParent()->getTypeForDecl(), 0);
551       llvm::Type *Ty = this->CGF->ConvertType(RT);
552       Address DstAddr = this->getAddrWithOffset(Addrs[DstIdx], Offset);
553       LValue DstBase =
554           this->CGF->MakeAddrLValue(DstAddr.withElementType(Ty), FT);
555       DstLV = this->CGF->EmitLValueForField(DstBase, FD);
556       Address SrcAddr = this->getAddrWithOffset(Addrs[SrcIdx], Offset);
557       LValue SrcBase =
558           this->CGF->MakeAddrLValue(SrcAddr.withElementType(Ty), FT);
559       SrcLV = this->CGF->EmitLValueForField(SrcBase, FD);
560     } else {
561       llvm::Type *Ty = this->CGF->ConvertTypeForMem(FT);
562       Address DstAddr = Addrs[DstIdx].withElementType(Ty);
563       Address SrcAddr = Addrs[SrcIdx].withElementType(Ty);
564       DstLV = this->CGF->MakeAddrLValue(DstAddr, FT);
565       SrcLV = this->CGF->MakeAddrLValue(SrcAddr, FT);
566     }
567     RValue SrcVal = this->CGF->EmitLoadOfLValue(SrcLV, SourceLocation());
568     this->CGF->EmitStoreThroughLValue(SrcVal, DstLV);
569   }
570 };
571 
572 // These classes that emit the special functions for a non-trivial struct.
573 struct GenDestructor : StructVisitor<GenDestructor>,
574                        GenFuncBase<GenDestructor>,
575                        DestructedTypeVisitor<GenDestructor> {
576   using Super = DestructedTypeVisitor<GenDestructor>;
577   GenDestructor(ASTContext &Ctx) : StructVisitor<GenDestructor>(Ctx) {}
578 
579   void visitWithKind(QualType::DestructionKind DK, QualType FT,
580                      const FieldDecl *FD, CharUnits CurStructOffset,
581                      std::array<Address, 1> Addrs) {
582     if (const auto *AT = getContext().getAsArrayType(FT)) {
583       visitArray(DK, AT, FT.isVolatileQualified(), FD, CurStructOffset, Addrs);
584       return;
585     }
586 
587     Super::visitWithKind(DK, FT, FD, CurStructOffset, Addrs);
588   }
589 
590   void visitARCStrong(QualType QT, const FieldDecl *FD,
591                       CharUnits CurStructOffset, std::array<Address, 1> Addrs) {
592     CGF->destroyARCStrongImprecise(
593         *CGF, getAddrWithOffset(Addrs[DstIdx], CurStructOffset, FD), QT);
594   }
595 
596   void visitARCWeak(QualType QT, const FieldDecl *FD, CharUnits CurStructOffset,
597                     std::array<Address, 1> Addrs) {
598     CGF->destroyARCWeak(
599         *CGF, getAddrWithOffset(Addrs[DstIdx], CurStructOffset, FD), QT);
600   }
601 
602   void callSpecialFunction(QualType FT, CharUnits Offset,
603                            std::array<Address, 1> Addrs) {
604     CGF->callCStructDestructor(
605         CGF->MakeAddrLValue(getAddrWithOffset(Addrs[DstIdx], Offset), FT));
606   }
607 };
608 
609 struct GenDefaultInitialize
610     : StructVisitor<GenDefaultInitialize>,
611       GenFuncBase<GenDefaultInitialize>,
612       DefaultInitializedTypeVisitor<GenDefaultInitialize> {
613   using Super = DefaultInitializedTypeVisitor<GenDefaultInitialize>;
614   typedef GenFuncBase<GenDefaultInitialize> GenFuncBaseTy;
615 
616   GenDefaultInitialize(ASTContext &Ctx)
617       : StructVisitor<GenDefaultInitialize>(Ctx) {}
618 
619   void visitWithKind(QualType::PrimitiveDefaultInitializeKind PDIK, QualType FT,
620                      const FieldDecl *FD, CharUnits CurStructOffset,
621                      std::array<Address, 1> Addrs) {
622     if (const auto *AT = getContext().getAsArrayType(FT)) {
623       visitArray(PDIK, AT, FT.isVolatileQualified(), FD, CurStructOffset,
624                  Addrs);
625       return;
626     }
627 
628     Super::visitWithKind(PDIK, FT, FD, CurStructOffset, Addrs);
629   }
630 
631   void visitARCStrong(QualType QT, const FieldDecl *FD,
632                       CharUnits CurStructOffset, std::array<Address, 1> Addrs) {
633     CGF->EmitNullInitialization(
634         getAddrWithOffset(Addrs[DstIdx], CurStructOffset, FD), QT);
635   }
636 
637   void visitARCWeak(QualType QT, const FieldDecl *FD, CharUnits CurStructOffset,
638                     std::array<Address, 1> Addrs) {
639     CGF->EmitNullInitialization(
640         getAddrWithOffset(Addrs[DstIdx], CurStructOffset, FD), QT);
641   }
642 
643   template <class FieldKind, size_t... Is>
644   void visitArray(FieldKind FK, const ArrayType *AT, bool IsVolatile,
645                   const FieldDecl *FD, CharUnits CurStructOffset,
646                   std::array<Address, 1> Addrs) {
647     if (!FK)
648       return visitTrivial(QualType(AT, 0), FD, CurStructOffset, Addrs);
649 
650     ASTContext &Ctx = getContext();
651     CharUnits Size = Ctx.getTypeSizeInChars(QualType(AT, 0));
652     QualType EltTy = Ctx.getBaseElementType(QualType(AT, 0));
653 
654     if (Size < CharUnits::fromQuantity(16) || EltTy->getAs<RecordType>()) {
655       GenFuncBaseTy::visitArray(FK, AT, IsVolatile, FD, CurStructOffset, Addrs);
656       return;
657     }
658 
659     llvm::Constant *SizeVal = CGF->Builder.getInt64(Size.getQuantity());
660     Address DstAddr = getAddrWithOffset(Addrs[DstIdx], CurStructOffset, FD);
661     Address Loc = DstAddr.withElementType(CGF->Int8Ty);
662     CGF->Builder.CreateMemSet(Loc, CGF->Builder.getInt8(0), SizeVal,
663                               IsVolatile);
664   }
665 
666   void callSpecialFunction(QualType FT, CharUnits Offset,
667                            std::array<Address, 1> Addrs) {
668     CGF->callCStructDefaultConstructor(
669         CGF->MakeAddrLValue(getAddrWithOffset(Addrs[DstIdx], Offset), FT));
670   }
671 };
672 
673 struct GenCopyConstructor : GenBinaryFunc<GenCopyConstructor, false> {
674   GenCopyConstructor(ASTContext &Ctx)
675       : GenBinaryFunc<GenCopyConstructor, false>(Ctx) {}
676 
677   void visitARCStrong(QualType QT, const FieldDecl *FD,
678                       CharUnits CurStructOffset, std::array<Address, 2> Addrs) {
679     Addrs[DstIdx] = getAddrWithOffset(Addrs[DstIdx], CurStructOffset, FD);
680     Addrs[SrcIdx] = getAddrWithOffset(Addrs[SrcIdx], CurStructOffset, FD);
681     llvm::Value *SrcVal = CGF->EmitLoadOfScalar(
682         Addrs[SrcIdx], QT.isVolatileQualified(), QT, SourceLocation());
683     llvm::Value *Val = CGF->EmitARCRetain(QT, SrcVal);
684     CGF->EmitStoreOfScalar(Val, CGF->MakeAddrLValue(Addrs[DstIdx], QT), true);
685   }
686 
687   void visitARCWeak(QualType QT, const FieldDecl *FD, CharUnits CurStructOffset,
688                     std::array<Address, 2> Addrs) {
689     Addrs[DstIdx] = getAddrWithOffset(Addrs[DstIdx], CurStructOffset, FD);
690     Addrs[SrcIdx] = getAddrWithOffset(Addrs[SrcIdx], CurStructOffset, FD);
691     CGF->EmitARCCopyWeak(Addrs[DstIdx], Addrs[SrcIdx]);
692   }
693 
694   void callSpecialFunction(QualType FT, CharUnits Offset,
695                            std::array<Address, 2> Addrs) {
696     Addrs[DstIdx] = getAddrWithOffset(Addrs[DstIdx], Offset);
697     Addrs[SrcIdx] = getAddrWithOffset(Addrs[SrcIdx], Offset);
698     CGF->callCStructCopyConstructor(CGF->MakeAddrLValue(Addrs[DstIdx], FT),
699                                     CGF->MakeAddrLValue(Addrs[SrcIdx], FT));
700   }
701 };
702 
703 struct GenMoveConstructor : GenBinaryFunc<GenMoveConstructor, true> {
704   GenMoveConstructor(ASTContext &Ctx)
705       : GenBinaryFunc<GenMoveConstructor, true>(Ctx) {}
706 
707   void visitARCStrong(QualType QT, const FieldDecl *FD,
708                       CharUnits CurStructOffset, std::array<Address, 2> Addrs) {
709     Addrs[DstIdx] = getAddrWithOffset(Addrs[DstIdx], CurStructOffset, FD);
710     Addrs[SrcIdx] = getAddrWithOffset(Addrs[SrcIdx], CurStructOffset, FD);
711     LValue SrcLV = CGF->MakeAddrLValue(Addrs[SrcIdx], QT);
712     llvm::Value *SrcVal =
713         CGF->EmitLoadOfLValue(SrcLV, SourceLocation()).getScalarVal();
714     CGF->EmitStoreOfScalar(getNullForVariable(SrcLV.getAddress(*CGF)), SrcLV);
715     CGF->EmitStoreOfScalar(SrcVal, CGF->MakeAddrLValue(Addrs[DstIdx], QT),
716                            /* isInitialization */ true);
717   }
718 
719   void visitARCWeak(QualType QT, const FieldDecl *FD, CharUnits CurStructOffset,
720                     std::array<Address, 2> Addrs) {
721     Addrs[DstIdx] = getAddrWithOffset(Addrs[DstIdx], CurStructOffset, FD);
722     Addrs[SrcIdx] = getAddrWithOffset(Addrs[SrcIdx], CurStructOffset, FD);
723     CGF->EmitARCMoveWeak(Addrs[DstIdx], Addrs[SrcIdx]);
724   }
725 
726   void callSpecialFunction(QualType FT, CharUnits Offset,
727                            std::array<Address, 2> Addrs) {
728     Addrs[DstIdx] = getAddrWithOffset(Addrs[DstIdx], Offset);
729     Addrs[SrcIdx] = getAddrWithOffset(Addrs[SrcIdx], Offset);
730     CGF->callCStructMoveConstructor(CGF->MakeAddrLValue(Addrs[DstIdx], FT),
731                                     CGF->MakeAddrLValue(Addrs[SrcIdx], FT));
732   }
733 };
734 
735 struct GenCopyAssignment : GenBinaryFunc<GenCopyAssignment, false> {
736   GenCopyAssignment(ASTContext &Ctx)
737       : GenBinaryFunc<GenCopyAssignment, false>(Ctx) {}
738 
739   void visitARCStrong(QualType QT, const FieldDecl *FD,
740                       CharUnits CurStructOffset, std::array<Address, 2> Addrs) {
741     Addrs[DstIdx] = getAddrWithOffset(Addrs[DstIdx], CurStructOffset, FD);
742     Addrs[SrcIdx] = getAddrWithOffset(Addrs[SrcIdx], CurStructOffset, FD);
743     llvm::Value *SrcVal = CGF->EmitLoadOfScalar(
744         Addrs[SrcIdx], QT.isVolatileQualified(), QT, SourceLocation());
745     CGF->EmitARCStoreStrong(CGF->MakeAddrLValue(Addrs[DstIdx], QT), SrcVal,
746                             false);
747   }
748 
749   void visitARCWeak(QualType QT, const FieldDecl *FD, CharUnits CurStructOffset,
750                     std::array<Address, 2> Addrs) {
751     Addrs[DstIdx] = getAddrWithOffset(Addrs[DstIdx], CurStructOffset, FD);
752     Addrs[SrcIdx] = getAddrWithOffset(Addrs[SrcIdx], CurStructOffset, FD);
753     CGF->emitARCCopyAssignWeak(QT, Addrs[DstIdx], Addrs[SrcIdx]);
754   }
755 
756   void callSpecialFunction(QualType FT, CharUnits Offset,
757                            std::array<Address, 2> Addrs) {
758     Addrs[DstIdx] = getAddrWithOffset(Addrs[DstIdx], Offset);
759     Addrs[SrcIdx] = getAddrWithOffset(Addrs[SrcIdx], Offset);
760     CGF->callCStructCopyAssignmentOperator(
761         CGF->MakeAddrLValue(Addrs[DstIdx], FT),
762         CGF->MakeAddrLValue(Addrs[SrcIdx], FT));
763   }
764 };
765 
766 struct GenMoveAssignment : GenBinaryFunc<GenMoveAssignment, true> {
767   GenMoveAssignment(ASTContext &Ctx)
768       : GenBinaryFunc<GenMoveAssignment, true>(Ctx) {}
769 
770   void visitARCStrong(QualType QT, const FieldDecl *FD,
771                       CharUnits CurStructOffset, std::array<Address, 2> Addrs) {
772     Addrs[DstIdx] = getAddrWithOffset(Addrs[DstIdx], CurStructOffset, FD);
773     Addrs[SrcIdx] = getAddrWithOffset(Addrs[SrcIdx], CurStructOffset, FD);
774     LValue SrcLV = CGF->MakeAddrLValue(Addrs[SrcIdx], QT);
775     llvm::Value *SrcVal =
776         CGF->EmitLoadOfLValue(SrcLV, SourceLocation()).getScalarVal();
777     CGF->EmitStoreOfScalar(getNullForVariable(SrcLV.getAddress(*CGF)), SrcLV);
778     LValue DstLV = CGF->MakeAddrLValue(Addrs[DstIdx], QT);
779     llvm::Value *DstVal =
780         CGF->EmitLoadOfLValue(DstLV, SourceLocation()).getScalarVal();
781     CGF->EmitStoreOfScalar(SrcVal, DstLV);
782     CGF->EmitARCRelease(DstVal, ARCImpreciseLifetime);
783   }
784 
785   void visitARCWeak(QualType QT, const FieldDecl *FD, CharUnits CurStructOffset,
786                     std::array<Address, 2> Addrs) {
787     Addrs[DstIdx] = getAddrWithOffset(Addrs[DstIdx], CurStructOffset, FD);
788     Addrs[SrcIdx] = getAddrWithOffset(Addrs[SrcIdx], CurStructOffset, FD);
789     CGF->emitARCMoveAssignWeak(QT, Addrs[DstIdx], Addrs[SrcIdx]);
790   }
791 
792   void callSpecialFunction(QualType FT, CharUnits Offset,
793                            std::array<Address, 2> Addrs) {
794     Addrs[DstIdx] = getAddrWithOffset(Addrs[DstIdx], Offset);
795     Addrs[SrcIdx] = getAddrWithOffset(Addrs[SrcIdx], Offset);
796     CGF->callCStructMoveAssignmentOperator(
797         CGF->MakeAddrLValue(Addrs[DstIdx], FT),
798         CGF->MakeAddrLValue(Addrs[SrcIdx], FT));
799   }
800 };
801 
802 } // namespace
803 
804 void CodeGenFunction::destroyNonTrivialCStruct(CodeGenFunction &CGF,
805                                                Address Addr, QualType Type) {
806   CGF.callCStructDestructor(CGF.MakeAddrLValue(Addr, Type));
807 }
808 
809 // Default-initialize a variable that is a non-trivial struct or an array of
810 // such structure.
811 void CodeGenFunction::defaultInitNonTrivialCStructVar(LValue Dst) {
812   GenDefaultInitialize Gen(getContext());
813   Address DstPtr = Dst.getAddress(*this).withElementType(CGM.Int8PtrTy);
814   Gen.setCGF(this);
815   QualType QT = Dst.getType();
816   QT = Dst.isVolatile() ? QT.withVolatile() : QT;
817   Gen.visit(QT, nullptr, CharUnits::Zero(), std::array<Address, 1>({{DstPtr}}));
818 }
819 
820 template <class G, size_t N>
821 static void callSpecialFunction(G &&Gen, StringRef FuncName, QualType QT,
822                                 bool IsVolatile, CodeGenFunction &CGF,
823                                 std::array<Address, N> Addrs) {
824   auto SetArtificialLoc = ApplyDebugLocation::CreateArtificial(CGF);
825   for (unsigned I = 0; I < N; ++I)
826     Addrs[I] = Addrs[I].withElementType(CGF.CGM.Int8PtrTy);
827   QT = IsVolatile ? QT.withVolatile() : QT;
828   Gen.callFunc(FuncName, QT, Addrs, CGF);
829 }
830 
831 template <class G, size_t N>
832 static llvm::Function *
833 getSpecialFunction(G &&Gen, StringRef FuncName, QualType QT, bool IsVolatile,
834                    std::array<CharUnits, N> Alignments, CodeGenModule &CGM) {
835   QT = IsVolatile ? QT.withVolatile() : QT;
836   // The following call requires an array of addresses as arguments, but doesn't
837   // actually use them (it overwrites them with the addresses of the arguments
838   // of the created function).
839   return Gen.getFunction(FuncName, QT, Alignments, CGM);
840 }
841 
842 // Functions to emit calls to the special functions of a non-trivial C struct.
843 void CodeGenFunction::callCStructDefaultConstructor(LValue Dst) {
844   bool IsVolatile = Dst.isVolatile();
845   Address DstPtr = Dst.getAddress(*this);
846   QualType QT = Dst.getType();
847   GenDefaultInitializeFuncName GenName(DstPtr.getAlignment(), getContext());
848   std::string FuncName = GenName.getName(QT, IsVolatile);
849   callSpecialFunction(GenDefaultInitialize(getContext()), FuncName, QT,
850                       IsVolatile, *this, std::array<Address, 1>({{DstPtr}}));
851 }
852 
853 std::string CodeGenFunction::getNonTrivialCopyConstructorStr(
854     QualType QT, CharUnits Alignment, bool IsVolatile, ASTContext &Ctx) {
855   GenBinaryFuncName<false> GenName("", Alignment, Alignment, Ctx);
856   return GenName.getName(QT, IsVolatile);
857 }
858 
859 std::string CodeGenFunction::getNonTrivialDestructorStr(QualType QT,
860                                                         CharUnits Alignment,
861                                                         bool IsVolatile,
862                                                         ASTContext &Ctx) {
863   GenDestructorFuncName GenName("", Alignment, Ctx);
864   return GenName.getName(QT, IsVolatile);
865 }
866 
867 void CodeGenFunction::callCStructDestructor(LValue Dst) {
868   bool IsVolatile = Dst.isVolatile();
869   Address DstPtr = Dst.getAddress(*this);
870   QualType QT = Dst.getType();
871   GenDestructorFuncName GenName("__destructor_", DstPtr.getAlignment(),
872                                 getContext());
873   std::string FuncName = GenName.getName(QT, IsVolatile);
874   callSpecialFunction(GenDestructor(getContext()), FuncName, QT, IsVolatile,
875                       *this, std::array<Address, 1>({{DstPtr}}));
876 }
877 
878 void CodeGenFunction::callCStructCopyConstructor(LValue Dst, LValue Src) {
879   bool IsVolatile = Dst.isVolatile() || Src.isVolatile();
880   Address DstPtr = Dst.getAddress(*this), SrcPtr = Src.getAddress(*this);
881   QualType QT = Dst.getType();
882   GenBinaryFuncName<false> GenName("__copy_constructor_", DstPtr.getAlignment(),
883                                    SrcPtr.getAlignment(), getContext());
884   std::string FuncName = GenName.getName(QT, IsVolatile);
885   callSpecialFunction(GenCopyConstructor(getContext()), FuncName, QT,
886                       IsVolatile, *this,
887                       std::array<Address, 2>({{DstPtr, SrcPtr}}));
888 }
889 
890 void CodeGenFunction::callCStructCopyAssignmentOperator(LValue Dst, LValue Src
891 
892 ) {
893   bool IsVolatile = Dst.isVolatile() || Src.isVolatile();
894   Address DstPtr = Dst.getAddress(*this), SrcPtr = Src.getAddress(*this);
895   QualType QT = Dst.getType();
896   GenBinaryFuncName<false> GenName("__copy_assignment_", DstPtr.getAlignment(),
897                                    SrcPtr.getAlignment(), getContext());
898   std::string FuncName = GenName.getName(QT, IsVolatile);
899   callSpecialFunction(GenCopyAssignment(getContext()), FuncName, QT, IsVolatile,
900                       *this, std::array<Address, 2>({{DstPtr, SrcPtr}}));
901 }
902 
903 void CodeGenFunction::callCStructMoveConstructor(LValue Dst, LValue Src) {
904   bool IsVolatile = Dst.isVolatile() || Src.isVolatile();
905   Address DstPtr = Dst.getAddress(*this), SrcPtr = Src.getAddress(*this);
906   QualType QT = Dst.getType();
907   GenBinaryFuncName<true> GenName("__move_constructor_", DstPtr.getAlignment(),
908                                   SrcPtr.getAlignment(), getContext());
909   std::string FuncName = GenName.getName(QT, IsVolatile);
910   callSpecialFunction(GenMoveConstructor(getContext()), FuncName, QT,
911                       IsVolatile, *this,
912                       std::array<Address, 2>({{DstPtr, SrcPtr}}));
913 }
914 
915 void CodeGenFunction::callCStructMoveAssignmentOperator(LValue Dst, LValue Src
916 
917 ) {
918   bool IsVolatile = Dst.isVolatile() || Src.isVolatile();
919   Address DstPtr = Dst.getAddress(*this), SrcPtr = Src.getAddress(*this);
920   QualType QT = Dst.getType();
921   GenBinaryFuncName<true> GenName("__move_assignment_", DstPtr.getAlignment(),
922                                   SrcPtr.getAlignment(), getContext());
923   std::string FuncName = GenName.getName(QT, IsVolatile);
924   callSpecialFunction(GenMoveAssignment(getContext()), FuncName, QT, IsVolatile,
925                       *this, std::array<Address, 2>({{DstPtr, SrcPtr}}));
926 }
927 
928 llvm::Function *clang::CodeGen::getNonTrivialCStructDefaultConstructor(
929     CodeGenModule &CGM, CharUnits DstAlignment, bool IsVolatile, QualType QT) {
930   ASTContext &Ctx = CGM.getContext();
931   GenDefaultInitializeFuncName GenName(DstAlignment, Ctx);
932   std::string FuncName = GenName.getName(QT, IsVolatile);
933   return getSpecialFunction(GenDefaultInitialize(Ctx), FuncName, QT, IsVolatile,
934                             std::array<CharUnits, 1>({{DstAlignment}}), CGM);
935 }
936 
937 llvm::Function *clang::CodeGen::getNonTrivialCStructCopyConstructor(
938     CodeGenModule &CGM, CharUnits DstAlignment, CharUnits SrcAlignment,
939     bool IsVolatile, QualType QT) {
940   ASTContext &Ctx = CGM.getContext();
941   GenBinaryFuncName<false> GenName("__copy_constructor_", DstAlignment,
942                                    SrcAlignment, Ctx);
943   std::string FuncName = GenName.getName(QT, IsVolatile);
944   return getSpecialFunction(
945       GenCopyConstructor(Ctx), FuncName, QT, IsVolatile,
946       std::array<CharUnits, 2>({{DstAlignment, SrcAlignment}}), CGM);
947 }
948 
949 llvm::Function *clang::CodeGen::getNonTrivialCStructMoveConstructor(
950     CodeGenModule &CGM, CharUnits DstAlignment, CharUnits SrcAlignment,
951     bool IsVolatile, QualType QT) {
952   ASTContext &Ctx = CGM.getContext();
953   GenBinaryFuncName<true> GenName("__move_constructor_", DstAlignment,
954                                   SrcAlignment, Ctx);
955   std::string FuncName = GenName.getName(QT, IsVolatile);
956   return getSpecialFunction(
957       GenMoveConstructor(Ctx), FuncName, QT, IsVolatile,
958       std::array<CharUnits, 2>({{DstAlignment, SrcAlignment}}), CGM);
959 }
960 
961 llvm::Function *clang::CodeGen::getNonTrivialCStructCopyAssignmentOperator(
962     CodeGenModule &CGM, CharUnits DstAlignment, CharUnits SrcAlignment,
963     bool IsVolatile, QualType QT) {
964   ASTContext &Ctx = CGM.getContext();
965   GenBinaryFuncName<false> GenName("__copy_assignment_", DstAlignment,
966                                    SrcAlignment, Ctx);
967   std::string FuncName = GenName.getName(QT, IsVolatile);
968   return getSpecialFunction(
969       GenCopyAssignment(Ctx), FuncName, QT, IsVolatile,
970       std::array<CharUnits, 2>({{DstAlignment, SrcAlignment}}), CGM);
971 }
972 
973 llvm::Function *clang::CodeGen::getNonTrivialCStructMoveAssignmentOperator(
974     CodeGenModule &CGM, CharUnits DstAlignment, CharUnits SrcAlignment,
975     bool IsVolatile, QualType QT) {
976   ASTContext &Ctx = CGM.getContext();
977   GenBinaryFuncName<true> GenName("__move_assignment_", DstAlignment,
978                                   SrcAlignment, Ctx);
979   std::string FuncName = GenName.getName(QT, IsVolatile);
980   return getSpecialFunction(
981       GenMoveAssignment(Ctx), FuncName, QT, IsVolatile,
982       std::array<CharUnits, 2>({{DstAlignment, SrcAlignment}}), CGM);
983 }
984 
985 llvm::Function *clang::CodeGen::getNonTrivialCStructDestructor(
986     CodeGenModule &CGM, CharUnits DstAlignment, bool IsVolatile, QualType QT) {
987   ASTContext &Ctx = CGM.getContext();
988   GenDestructorFuncName GenName("__destructor_", DstAlignment, Ctx);
989   std::string FuncName = GenName.getName(QT, IsVolatile);
990   return getSpecialFunction(GenDestructor(Ctx), FuncName, QT, IsVolatile,
991                             std::array<CharUnits, 1>({{DstAlignment}}), CGM);
992 }
993