clang/lib/AST/Mangle.cpp

   1 //===--- Mangle.cpp - Mangle C++ Names --------------------------*- C++ -*-===//
   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 // Implements generic name mangling support for blocks and Objective-C.
  10 //
  11 //===----------------------------------------------------------------------===//
  12 #include "clang/AST/Attr.h"
  13 #include "clang/AST/ASTContext.h"
  14 #include "clang/AST/Decl.h"
  15 #include "clang/AST/DeclCXX.h"
  16 #include "clang/AST/DeclObjC.h"
  17 #include "clang/AST/DeclTemplate.h"
  18 #include "clang/AST/ExprCXX.h"
  19 #include "clang/AST/Mangle.h"
  20 #include "clang/AST/VTableBuilder.h"
  21 #include "clang/Basic/ABI.h"
  22 #include "clang/Basic/SourceManager.h"
  23 #include "clang/Basic/TargetInfo.h"
  24 #include "llvm/ADT/StringExtras.h"
  25 #include "llvm/IR/DataLayout.h"
  26 #include "llvm/IR/Mangler.h"
  27 #include "llvm/Support/ErrorHandling.h"
  28 #include "llvm/Support/Format.h"
  29 #include "llvm/Support/raw_ostream.h"
  30
  31 using namespace clang;
  32
  33 // FIXME: For blocks we currently mimic GCC's mangling scheme, which leaves
  34 // much to be desired. Come up with a better mangling scheme.
  35
  36 static void mangleFunctionBlock(MangleContext &Context,
  37                                 StringRef Outer,
  38                                 const BlockDecl *BD,
  39                                 raw_ostream &Out) {
  40   unsigned discriminator = Context.getBlockId(BD, true);
  41   if (discriminator == 0)
  42     Out << "__" << Outer << "_block_invoke";
  43   else
  44     Out << "__" << Outer << "_block_invoke_" << discriminator+1;
  45 }
  46
  47 void MangleContext::anchor() { }
  48
  49 enum CCMangling {
  50   CCM_Other,
  51   CCM_Fast,
  52   CCM_RegCall,
  53   CCM_Vector,
  54   CCM_Std,
  55   CCM_WasmMainArgcArgv
  56 };
  57
  58 static bool isExternC(const NamedDecl *ND) {
  59   if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND))
  60     return FD->isExternC();
  61   if (const VarDecl *VD = dyn_cast<VarDecl>(ND))
  62     return VD->isExternC();
  63   return false;
  64 }
  65
  66 static CCMangling getCallingConvMangling(const ASTContext &Context,
  67                                          const NamedDecl *ND) {
  68   const TargetInfo &TI = Context.getTargetInfo();
  69   const llvm::Triple &Triple = TI.getTriple();
  70
  71   // On wasm, the argc/argv form of "main" is renamed so that the startup code
  72   // can call it with the correct function signature.
  73   if (Triple.isWasm())
  74     if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND))
  75       if (FD->isMain() && FD->getNumParams() == 2)
  76         return CCM_WasmMainArgcArgv;
  77
  78   if (!Triple.isOSWindows() || !Triple.isX86())
  79     return CCM_Other;
  80
  81   if (Context.getLangOpts().CPlusPlus && !isExternC(ND) &&
  82       TI.getCXXABI() == TargetCXXABI::Microsoft)
  83     return CCM_Other;
  84
  85   const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND);
  86   if (!FD)
  87     return CCM_Other;
  88   QualType T = FD->getType();
  89
  90   const FunctionType *FT = T->castAs<FunctionType>();
  91
  92   CallingConv CC = FT->getCallConv();
  93   switch (CC) {
  94   default:
  95     return CCM_Other;
  96   case CC_X86FastCall:
  97     return CCM_Fast;
  98   case CC_X86StdCall:
  99     return CCM_Std;
 100   case CC_X86VectorCall:
 101     return CCM_Vector;
 102   }
 103 }
 104
 105 bool MangleContext::shouldMangleDeclName(const NamedDecl *D) {
 106   const ASTContext &ASTContext = getASTContext();
 107
 108   CCMangling CC = getCallingConvMangling(ASTContext, D);
 109   if (CC != CCM_Other)
 110     return true;
 111
 112   // If the declaration has an owning module for linkage purposes that needs to
 113   // be mangled, we must mangle its name.
 114   if (!D->hasExternalFormalLinkage() && D->getOwningModuleForLinkage())
 115     return true;
 116
 117   // C functions with internal linkage have to be mangled with option
 118   // -funique-internal-linkage-names.
 119   if (!getASTContext().getLangOpts().CPlusPlus &&
 120       isUniqueInternalLinkageDecl(D))
 121     return true;
 122
 123   // In C, functions with no attributes never need to be mangled. Fastpath them.
 124   if (!getASTContext().getLangOpts().CPlusPlus && !D->hasAttrs())
 125     return false;
 126
 127   // Any decl can be declared with __asm("foo") on it, and this takes precedence
 128   // over all other naming in the .o file.
 129   if (D->hasAttr<AsmLabelAttr>())
 130     return true;
 131
 132   // Declarations that don't have identifier names always need to be mangled.
 133   if (isa<MSGuidDecl>(D))
 134     return true;
 135
 136   return shouldMangleCXXName(D);
 137 }
 138
 139 void MangleContext::mangleName(GlobalDecl GD, raw_ostream &Out) {
 140   const ASTContext &ASTContext = getASTContext();
 141   const NamedDecl *D = cast<NamedDecl>(GD.getDecl());
 142
 143   // Any decl can be declared with __asm("foo") on it, and this takes precedence
 144   // over all other naming in the .o file.
 145   if (const AsmLabelAttr *ALA = D->getAttr<AsmLabelAttr>()) {
 146     // If we have an asm name, then we use it as the mangling.
 147
 148     // If the label isn't literal, or if this is an alias for an LLVM intrinsic,
 149     // do not add a "\01" prefix.
 150     if (!ALA->getIsLiteralLabel() || ALA->getLabel().startswith("llvm.")) {
 151       Out << ALA->getLabel();
 152       return;
 153     }
 154
 155     // Adding the prefix can cause problems when one file has a "foo" and
 156     // another has a "\01foo". That is known to happen on ELF with the
 157     // tricks normally used for producing aliases (PR9177). Fortunately the
 158     // llvm mangler on ELF is a nop, so we can just avoid adding the \01
 159     // marker.
 160     StringRef UserLabelPrefix =
 161         getASTContext().getTargetInfo().getUserLabelPrefix();
 162 #ifndef NDEBUG
 163     char GlobalPrefix =
 164         llvm::DataLayout(getASTContext().getTargetInfo().getDataLayoutString())
 165             .getGlobalPrefix();
 166     assert((UserLabelPrefix.empty() && !GlobalPrefix) ||
 167            (UserLabelPrefix.size() == 1 && UserLabelPrefix[0] == GlobalPrefix));
 168 #endif
 169     if (!UserLabelPrefix.empty())
 170       Out << '\01'; // LLVM IR Marker for __asm("foo")
 171
 172     Out << ALA->getLabel();
 173     return;
 174   }
 175
 176   if (auto *GD = dyn_cast<MSGuidDecl>(D))
 177     return mangleMSGuidDecl(GD, Out);
 178
 179   CCMangling CC = getCallingConvMangling(ASTContext, D);
 180
 181   if (CC == CCM_WasmMainArgcArgv) {
 182     Out << "__main_argc_argv";
 183     return;
 184   }
 185
 186   bool MCXX = shouldMangleCXXName(D);
 187   const TargetInfo &TI = Context.getTargetInfo();
 188   if (CC == CCM_Other || (MCXX && TI.getCXXABI() == TargetCXXABI::Microsoft)) {
 189     if (const ObjCMethodDecl *OMD = dyn_cast<ObjCMethodDecl>(D))
 190       mangleObjCMethodNameAsSourceName(OMD, Out);
 191     else
 192       mangleCXXName(GD, Out);
 193     return;
 194   }
 195
 196   Out << '\01';
 197   if (CC == CCM_Std)
 198     Out << '_';
 199   else if (CC == CCM_Fast)
 200     Out << '@';
 201   else if (CC == CCM_RegCall) {
 202     if (getASTContext().getLangOpts().RegCall4)
 203       Out << "__regcall4__";
 204     else
 205       Out << "__regcall3__";
 206   }
 207
 208   if (!MCXX)
 209     Out << D->getIdentifier()->getName();
 210   else if (const ObjCMethodDecl *OMD = dyn_cast<ObjCMethodDecl>(D))
 211     mangleObjCMethodNameAsSourceName(OMD, Out);
 212   else
 213     mangleCXXName(GD, Out);
 214
 215   const FunctionDecl *FD = cast<FunctionDecl>(D);
 216   const FunctionType *FT = FD->getType()->castAs<FunctionType>();
 217   const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT);
 218   if (CC == CCM_Vector)
 219     Out << '@';
 220   Out << '@';
 221   if (!Proto) {
 222     Out << '0';
 223     return;
 224   }
 225   assert(!Proto->isVariadic());
 226   unsigned ArgWords = 0;
 227   if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD))
 228     if (MD->isImplicitObjectMemberFunction())
 229       ++ArgWords;
 230   uint64_t DefaultPtrWidth = TI.getPointerWidth(LangAS::Default);
 231   for (const auto &AT : Proto->param_types()) {
 232     // If an argument type is incomplete there is no way to get its size to
 233     // correctly encode into the mangling scheme.
 234     // Follow GCCs behaviour by simply breaking out of the loop.
 235     if (AT->isIncompleteType())
 236       break;
 237     // Size should be aligned to pointer size.
 238     ArgWords += llvm::alignTo(ASTContext.getTypeSize(AT), DefaultPtrWidth) /
 239                 DefaultPtrWidth;
 240   }
 241   Out << ((DefaultPtrWidth / 8) * ArgWords);
 242 }
 243
 244 void MangleContext::mangleMSGuidDecl(const MSGuidDecl *GD, raw_ostream &Out) {
 245   // For now, follow the MSVC naming convention for GUID objects on all
 246   // targets.
 247   MSGuidDecl::Parts P = GD->getParts();
 248   Out << llvm::format("_GUID_%08" PRIx32 "_%04" PRIx32 "_%04" PRIx32 "_",
 249                       P.Part1, P.Part2, P.Part3);
 250   unsigned I = 0;
 251   for (uint8_t C : P.Part4And5) {
 252     Out << llvm::format("%02" PRIx8, C);
 253     if (++I == 2)
 254       Out << "_";
 255   }
 256 }
 257
 258 void MangleContext::mangleGlobalBlock(const BlockDecl *BD,
 259                                       const NamedDecl *ID,
 260                                       raw_ostream &Out) {
 261   unsigned discriminator = getBlockId(BD, false);
 262   if (ID) {
 263     if (shouldMangleDeclName(ID))
 264       mangleName(ID, Out);
 265     else {
 266       Out << ID->getIdentifier()->getName();
 267     }
 268   }
 269   if (discriminator == 0)
 270     Out << "_block_invoke";
 271   else
 272     Out << "_block_invoke_" << discriminator+1;
 273 }
 274
 275 void MangleContext::mangleCtorBlock(const CXXConstructorDecl *CD,
 276                                     CXXCtorType CT, const BlockDecl *BD,
 277                                     raw_ostream &ResStream) {
 278   SmallString<64> Buffer;
 279   llvm::raw_svector_ostream Out(Buffer);
 280   mangleName(GlobalDecl(CD, CT), Out);
 281   mangleFunctionBlock(*this, Buffer, BD, ResStream);
 282 }
 283
 284 void MangleContext::mangleDtorBlock(const CXXDestructorDecl *DD,
 285                                     CXXDtorType DT, const BlockDecl *BD,
 286                                     raw_ostream &ResStream) {
 287   SmallString<64> Buffer;
 288   llvm::raw_svector_ostream Out(Buffer);
 289   mangleName(GlobalDecl(DD, DT), Out);
 290   mangleFunctionBlock(*this, Buffer, BD, ResStream);
 291 }
 292
 293 void MangleContext::mangleBlock(const DeclContext *DC, const BlockDecl *BD,
 294                                 raw_ostream &Out) {
 295   assert(!isa<CXXConstructorDecl>(DC) && !isa<CXXDestructorDecl>(DC));
 296
 297   SmallString<64> Buffer;
 298   llvm::raw_svector_ostream Stream(Buffer);
 299   if (const ObjCMethodDecl *Method = dyn_cast<ObjCMethodDecl>(DC)) {
 300     mangleObjCMethodNameAsSourceName(Method, Stream);
 301   } else {
 302     assert((isa<NamedDecl>(DC) || isa<BlockDecl>(DC)) &&
 303            "expected a NamedDecl or BlockDecl");
 304     if (isa<BlockDecl>(DC))
 305       for (; DC && isa<BlockDecl>(DC); DC = DC->getParent())
 306         (void) getBlockId(cast<BlockDecl>(DC), true);
 307     assert((isa<TranslationUnitDecl>(DC) || isa<NamedDecl>(DC)) &&
 308            "expected a TranslationUnitDecl or a NamedDecl");
 309     if (const auto *CD = dyn_cast<CXXConstructorDecl>(DC))
 310       mangleCtorBlock(CD, /*CT*/ Ctor_Complete, BD, Out);
 311     else if (const auto *DD = dyn_cast<CXXDestructorDecl>(DC))
 312       mangleDtorBlock(DD, /*DT*/ Dtor_Complete, BD, Out);
 313     else if (auto ND = dyn_cast<NamedDecl>(DC)) {
 314       if (!shouldMangleDeclName(ND) && ND->getIdentifier())
 315         Stream << ND->getIdentifier()->getName();
 316       else {
 317         // FIXME: We were doing a mangleUnqualifiedName() before, but that's
 318         // a private member of a class that will soon itself be private to the
 319         // Itanium C++ ABI object. What should we do now? Right now, I'm just
 320         // calling the mangleName() method on the MangleContext; is there a
 321         // better way?
 322         mangleName(ND, Stream);
 323       }
 324     }
 325   }
 326   mangleFunctionBlock(*this, Buffer, BD, Out);
 327 }
 328
 329 void MangleContext::mangleObjCMethodName(const ObjCMethodDecl *MD,
 330                                          raw_ostream &OS,
 331                                          bool includePrefixByte,
 332                                          bool includeCategoryNamespace) {
 333   if (getASTContext().getLangOpts().ObjCRuntime.isGNUFamily()) {
 334     // This is the mangling we've always used on the GNU runtimes, but it
 335     // has obvious collisions in the face of underscores within class
 336     // names, category names, and selectors; maybe we should improve it.
 337
 338     OS << (MD->isClassMethod() ? "_c_" : "_i_")
 339        << MD->getClassInterface()->getName() << '_';
 340
 341     if (includeCategoryNamespace) {
 342       if (auto category = MD->getCategory())
 343         OS << category->getName();
 344     }
 345     OS << '_';
 346
 347     auto selector = MD->getSelector();
 348     for (unsigned slotIndex = 0,
 349                   numArgs = selector.getNumArgs(),
 350                   slotEnd = std::max(numArgs, 1U);
 351            slotIndex != slotEnd; ++slotIndex) {
 352       if (auto name = selector.getIdentifierInfoForSlot(slotIndex))
 353         OS << name->getName();
 354
 355       // Replace all the positions that would've been ':' with '_'.
 356       // That's after each slot except that a unary selector doesn't
 357       // end in ':'.
 358       if (numArgs)
 359         OS << '_';
 360     }
 361
 362     return;
 363   }
 364
 365   // \01+[ContainerName(CategoryName) SelectorName]
 366   if (includePrefixByte) {
 367     OS << '\01';
 368   }
 369   OS << (MD->isInstanceMethod() ? '-' : '+') << '[';
 370   if (const auto *CID = MD->getCategory()) {
 371     OS << CID->getClassInterface()->getName();
 372     if (includeCategoryNamespace) {
 373       OS << '(' << *CID << ')';
 374     }
 375   } else if (const auto *CD =
 376                  dyn_cast<ObjCContainerDecl>(MD->getDeclContext())) {
 377     OS << CD->getName();
 378   } else {
 379     llvm_unreachable("Unexpected ObjC method decl context");
 380   }
 381   OS << ' ';
 382   MD->getSelector().print(OS);
 383   OS << ']';
 384 }
 385
 386 void MangleContext::mangleObjCMethodNameAsSourceName(const ObjCMethodDecl *MD,
 387                                                      raw_ostream &Out) {
 388   SmallString<64> Name;
 389   llvm::raw_svector_ostream OS(Name);
 390
 391   mangleObjCMethodName(MD, OS, /*includePrefixByte=*/false,
 392                        /*includeCategoryNamespace=*/true);
 393   Out << OS.str().size() << OS.str();
 394 }
 395
 396 class ASTNameGenerator::Implementation {
 397   std::unique_ptr<MangleContext> MC;
 398   llvm::DataLayout DL;
 399
 400 public:
 401   explicit Implementation(ASTContext &Ctx)
 402       : MC(Ctx.createMangleContext()),
 403         DL(Ctx.getTargetInfo().getDataLayoutString()) {}
 404
 405   bool writeName(const Decl *D, raw_ostream &OS) {
 406     // First apply frontend mangling.
 407     SmallString<128> FrontendBuf;
 408     llvm::raw_svector_ostream FrontendBufOS(FrontendBuf);
 409     if (auto *FD = dyn_cast<FunctionDecl>(D)) {
 410       if (FD->isDependentContext())
 411         return true;
 412       if (writeFuncOrVarName(FD, FrontendBufOS))
 413         return true;
 414     } else if (auto *VD = dyn_cast<VarDecl>(D)) {
 415       if (writeFuncOrVarName(VD, FrontendBufOS))
 416         return true;
 417     } else if (auto *MD = dyn_cast<ObjCMethodDecl>(D)) {
 418       MC->mangleObjCMethodName(MD, OS, /*includePrefixByte=*/false,
 419                                /*includeCategoryNamespace=*/true);
 420       return false;
 421     } else if (auto *ID = dyn_cast<ObjCInterfaceDecl>(D)) {
 422       writeObjCClassName(ID, FrontendBufOS);
 423     } else {
 424       return true;
 425     }
 426
 427     // Now apply backend mangling.
 428     llvm::Mangler::getNameWithPrefix(OS, FrontendBufOS.str(), DL);
 429     return false;
 430   }
 431
 432   std::string getName(const Decl *D) {
 433     std::string Name;
 434     {
 435       llvm::raw_string_ostream OS(Name);
 436       writeName(D, OS);
 437     }
 438     return Name;
 439   }
 440
 441   enum ObjCKind {
 442     ObjCClass,
 443     ObjCMetaclass,
 444   };
 445
 446   static StringRef getClassSymbolPrefix(ObjCKind Kind,
 447                                         const ASTContext &Context) {
 448     if (Context.getLangOpts().ObjCRuntime.isGNUFamily())
 449       return Kind == ObjCMetaclass ? "_OBJC_METACLASS_" : "_OBJC_CLASS_";
 450     return Kind == ObjCMetaclass ? "OBJC_METACLASS_$_" : "OBJC_CLASS_$_";
 451   }
 452
 453   std::vector<std::string> getAllManglings(const ObjCContainerDecl *OCD) {
 454     StringRef ClassName;
 455     if (const auto *OID = dyn_cast<ObjCInterfaceDecl>(OCD))
 456       ClassName = OID->getObjCRuntimeNameAsString();
 457     else if (const auto *OID = dyn_cast<ObjCImplementationDecl>(OCD))
 458       ClassName = OID->getObjCRuntimeNameAsString();
 459
 460     if (ClassName.empty())
 461       return {};
 462
 463     auto Mangle = [&](ObjCKind Kind, StringRef ClassName) -> std::string {
 464       SmallString<40> Mangled;
 465       auto Prefix = getClassSymbolPrefix(Kind, OCD->getASTContext());
 466       llvm::Mangler::getNameWithPrefix(Mangled, Prefix + ClassName, DL);
 467       return std::string(Mangled.str());
 468     };
 469
 470     return {
 471         Mangle(ObjCClass, ClassName),
 472         Mangle(ObjCMetaclass, ClassName),
 473     };
 474   }
 475
 476   std::vector<std::string> getAllManglings(const Decl *D) {
 477     if (const auto *OCD = dyn_cast<ObjCContainerDecl>(D))
 478       return getAllManglings(OCD);
 479
 480     if (!(isa<CXXRecordDecl>(D) || isa<CXXMethodDecl>(D)))
 481       return {};
 482
 483     const NamedDecl *ND = cast<NamedDecl>(D);
 484
 485     ASTContext &Ctx = ND->getASTContext();
 486     std::unique_ptr<MangleContext> M(Ctx.createMangleContext());
 487
 488     std::vector<std::string> Manglings;
 489
 490     auto hasDefaultCXXMethodCC = [](ASTContext &C, const CXXMethodDecl *MD) {
 491       auto DefaultCC = C.getDefaultCallingConvention(/*IsVariadic=*/false,
 492                                                      /*IsCXXMethod=*/true);
 493       auto CC = MD->getType()->castAs<FunctionProtoType>()->getCallConv();
 494       return CC == DefaultCC;
 495     };
 496
 497     if (const auto *CD = dyn_cast_or_null<CXXConstructorDecl>(ND)) {
 498       Manglings.emplace_back(getMangledStructor(CD, Ctor_Base));
 499
 500       if (Ctx.getTargetInfo().getCXXABI().isItaniumFamily())
 501         if (!CD->getParent()->isAbstract())
 502           Manglings.emplace_back(getMangledStructor(CD, Ctor_Complete));
 503
 504       if (Ctx.getTargetInfo().getCXXABI().isMicrosoft())
 505         if (CD->hasAttr<DLLExportAttr>() && CD->isDefaultConstructor())
 506           if (!(hasDefaultCXXMethodCC(Ctx, CD) && CD->getNumParams() == 0))
 507             Manglings.emplace_back(getMangledStructor(CD, Ctor_DefaultClosure));
 508     } else if (const auto *DD = dyn_cast_or_null<CXXDestructorDecl>(ND)) {
 509       Manglings.emplace_back(getMangledStructor(DD, Dtor_Base));
 510       if (Ctx.getTargetInfo().getCXXABI().isItaniumFamily()) {
 511         Manglings.emplace_back(getMangledStructor(DD, Dtor_Complete));
 512         if (DD->isVirtual())
 513           Manglings.emplace_back(getMangledStructor(DD, Dtor_Deleting));
 514       }
 515     } else if (const auto *MD = dyn_cast_or_null<CXXMethodDecl>(ND)) {
 516       Manglings.emplace_back(getName(ND));
 517       if (MD->isVirtual())
 518         if (const auto *TIV = Ctx.getVTableContext()->getThunkInfo(MD))
 519           for (const auto &T : *TIV)
 520             Manglings.emplace_back(getMangledThunk(MD, T));
 521     }
 522
 523     return Manglings;
 524   }
 525
 526 private:
 527   bool writeFuncOrVarName(const NamedDecl *D, raw_ostream &OS) {
 528     if (MC->shouldMangleDeclName(D)) {
 529       GlobalDecl GD;
 530       if (const auto *CtorD = dyn_cast<CXXConstructorDecl>(D))
 531         GD = GlobalDecl(CtorD, Ctor_Complete);
 532       else if (const auto *DtorD = dyn_cast<CXXDestructorDecl>(D))
 533         GD = GlobalDecl(DtorD, Dtor_Complete);
 534       else if (D->hasAttr<CUDAGlobalAttr>())
 535         GD = GlobalDecl(cast<FunctionDecl>(D));
 536       else
 537         GD = GlobalDecl(D);
 538       MC->mangleName(GD, OS);
 539       return false;
 540     } else {
 541       IdentifierInfo *II = D->getIdentifier();
 542       if (!II)
 543         return true;
 544       OS << II->getName();
 545       return false;
 546     }
 547   }
 548
 549   void writeObjCClassName(const ObjCInterfaceDecl *D, raw_ostream &OS) {
 550     OS << getClassSymbolPrefix(ObjCClass, D->getASTContext());
 551     OS << D->getObjCRuntimeNameAsString();
 552   }
 553
 554   std::string getMangledStructor(const NamedDecl *ND, unsigned StructorType) {
 555     std::string FrontendBuf;
 556     llvm::raw_string_ostream FOS(FrontendBuf);
 557
 558     GlobalDecl GD;
 559     if (const auto *CD = dyn_cast_or_null<CXXConstructorDecl>(ND))
 560       GD = GlobalDecl(CD, static_cast<CXXCtorType>(StructorType));
 561     else if (const auto *DD = dyn_cast_or_null<CXXDestructorDecl>(ND))
 562       GD = GlobalDecl(DD, static_cast<CXXDtorType>(StructorType));
 563     MC->mangleName(GD, FOS);
 564
 565     std::string BackendBuf;
 566     llvm::raw_string_ostream BOS(BackendBuf);
 567
 568     llvm::Mangler::getNameWithPrefix(BOS, FOS.str(), DL);
 569
 570     return BOS.str();
 571   }
 572
 573   std::string getMangledThunk(const CXXMethodDecl *MD, const ThunkInfo &T) {
 574     std::string FrontendBuf;
 575     llvm::raw_string_ostream FOS(FrontendBuf);
 576
 577     MC->mangleThunk(MD, T, FOS);
 578
 579     std::string BackendBuf;
 580     llvm::raw_string_ostream BOS(BackendBuf);
 581
 582     llvm::Mangler::getNameWithPrefix(BOS, FOS.str(), DL);
 583
 584     return BOS.str();
 585   }
 586 };
 587
 588 ASTNameGenerator::ASTNameGenerator(ASTContext &Ctx)
 589     : Impl(std::make_unique<Implementation>(Ctx)) {}
 590
 591 ASTNameGenerator::~ASTNameGenerator() {}
 592
 593 bool ASTNameGenerator::writeName(const Decl *D, raw_ostream &OS) {
 594   return Impl->writeName(D, OS);
 595 }
 596
 597 std::string ASTNameGenerator::getName(const Decl *D) {
 598   return Impl->getName(D);
 599 }
 600
 601 std::vector<std::string> ASTNameGenerator::getAllManglings(const Decl *D) {
 602   return Impl->getAllManglings(D);
 603 }