tools/libclang/CIndexUSRs.cpp

   1 //===- CIndexUSR.cpp - Clang-C Source Indexing Library --------------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file implements the generation and use of USRs from CXEntities.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "CIndexer.h"
  15 #include "CXCursor.h"
  16 #include "CXString.h"
  17 #include "clang/AST/DeclTemplate.h"
  18 #include "clang/AST/DeclVisitor.h"
  19 #include "clang/Frontend/ASTUnit.h"
  20 #include "clang/Lex/PreprocessingRecord.h"
  21 #include "llvm/ADT/SmallString.h"
  22 #include "llvm/Support/raw_ostream.h"
  23
  24 using namespace clang;
  25 using namespace clang::cxstring;
  26
  27 //===----------------------------------------------------------------------===//
  28 // USR generation.
  29 //===----------------------------------------------------------------------===//
  30
  31 namespace {
  32 class USRGenerator : public DeclVisitor<USRGenerator> {
  33   llvm::OwningPtr<llvm::SmallString<128> > OwnedBuf;
  34   llvm::SmallVectorImpl<char> &Buf;
  35   llvm::raw_svector_ostream Out;
  36   bool IgnoreResults;
  37   ASTUnit *AU;
  38   bool generatedLoc;
  39
  40   llvm::DenseMap<const Type *, unsigned> TypeSubstitutions;
  41
  42 public:
  43   USRGenerator(const CXCursor *C = 0, llvm::SmallVectorImpl<char> *extBuf = 0)
  44   : OwnedBuf(extBuf ? 0 : new llvm::SmallString<128>()),
  45     Buf(extBuf ? *extBuf : *OwnedBuf.get()),
  46     Out(Buf),
  47     IgnoreResults(false),
  48     AU(C ? cxcursor::getCursorASTUnit(*C) : 0),
  49     generatedLoc(false)
  50   {
  51     // Add the USR space prefix.
  52     Out << "c:";
  53   }
  54
  55   llvm::StringRef str() {
  56     return Out.str();
  57   }
  58
  59   USRGenerator* operator->() { return this; }
  60
  61   template <typename T>
  62   llvm::raw_svector_ostream &operator<<(const T &x) {
  63     Out << x;
  64     return Out;
  65   }
  66
  67   bool ignoreResults() const { return IgnoreResults; }
  68
  69   // Visitation methods from generating USRs from AST elements.
  70   void VisitDeclContext(DeclContext *D);
  71   void VisitFieldDecl(FieldDecl *D);
  72   void VisitFunctionDecl(FunctionDecl *D);
  73   void VisitNamedDecl(NamedDecl *D);
  74   void VisitNamespaceDecl(NamespaceDecl *D);
  75   void VisitNamespaceAliasDecl(NamespaceAliasDecl *D);
  76   void VisitFunctionTemplateDecl(FunctionTemplateDecl *D);
  77   void VisitClassTemplateDecl(ClassTemplateDecl *D);
  78   void VisitObjCClassDecl(ObjCClassDecl *CD);
  79   void VisitObjCContainerDecl(ObjCContainerDecl *CD);
  80   void VisitObjCForwardProtocolDecl(ObjCForwardProtocolDecl *P);
  81   void VisitObjCMethodDecl(ObjCMethodDecl *MD);
  82   void VisitObjCPropertyDecl(ObjCPropertyDecl *D);
  83   void VisitObjCPropertyImplDecl(ObjCPropertyImplDecl *D);
  84   void VisitTagDecl(TagDecl *D);
  85   void VisitTypedefDecl(TypedefDecl *D);
  86   void VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D);
  87   void VisitVarDecl(VarDecl *D);
  88   void VisitNonTypeTemplateParmDecl(NonTypeTemplateParmDecl *D);
  89   void VisitTemplateTemplateParmDecl(TemplateTemplateParmDecl *D);
  90   void VisitLinkageSpecDecl(LinkageSpecDecl *D) {
  91     IgnoreResults = true;
  92   }
  93   void VisitUsingDirectiveDecl(UsingDirectiveDecl *D) {
  94     IgnoreResults = true;
  95   }
  96   void VisitUsingDecl(UsingDecl *D) {
  97     IgnoreResults = true;
  98   }
  99   void VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D) {
 100     IgnoreResults = true;
 101   }
 102   void VisitUnresolvedUsingTypenameDecl(UnresolvedUsingTypenameDecl *D) {
 103     IgnoreResults = true;
 104   }
 105
 106   /// Generate the string component containing the location of the
 107   ///  declaration.
 108   bool GenLoc(const Decl *D);
 109
 110   /// String generation methods used both by the visitation methods
 111   /// and from other clients that want to directly generate USRs.  These
 112   /// methods do not construct complete USRs (which incorporate the parents
 113   /// of an AST element), but only the fragments concerning the AST element
 114   /// itself.
 115
 116   /// Generate a USR for an Objective-C class.
 117   void GenObjCClass(llvm::StringRef cls);
 118   /// Generate a USR for an Objective-C class category.
 119   void GenObjCCategory(llvm::StringRef cls, llvm::StringRef cat);
 120   /// Generate a USR fragment for an Objective-C instance variable.  The
 121   /// complete USR can be created by concatenating the USR for the
 122   /// encompassing class with this USR fragment.
 123   void GenObjCIvar(llvm::StringRef ivar);
 124   /// Generate a USR fragment for an Objective-C method.
 125   void GenObjCMethod(llvm::StringRef sel, bool isInstanceMethod);
 126   /// Generate a USR fragment for an Objective-C property.
 127   void GenObjCProperty(llvm::StringRef prop);
 128   /// Generate a USR for an Objective-C protocol.
 129   void GenObjCProtocol(llvm::StringRef prot);
 130
 131   void VisitType(QualType T);
 132   void VisitTemplateParameterList(const TemplateParameterList *Params);
 133   void VisitTemplateName(TemplateName Name);
 134   void VisitTemplateArgument(const TemplateArgument &Arg);
 135
 136   /// Emit a Decl's name using NamedDecl::printName() and return true if
 137   ///  the decl had no name.
 138   bool EmitDeclName(const NamedDecl *D);
 139 };
 140
 141 } // end anonymous namespace
 142
 143 //===----------------------------------------------------------------------===//
 144 // Generating USRs from ASTS.
 145 //===----------------------------------------------------------------------===//
 146
 147 bool USRGenerator::EmitDeclName(const NamedDecl *D) {
 148   Out.flush();
 149   const unsigned startSize = Buf.size();
 150   D->printName(Out);
 151   Out.flush();
 152   const unsigned endSize = Buf.size();
 153   return startSize == endSize;
 154 }
 155
 156 static bool InAnonymousNamespace(const Decl *D) {
 157   if (const NamespaceDecl *ND = dyn_cast<NamespaceDecl>(D->getDeclContext()))
 158     return ND->isAnonymousNamespace();
 159   return false;
 160 }
 161
 162 static inline bool ShouldGenerateLocation(const NamedDecl *D) {
 163   return D->getLinkage() != ExternalLinkage && !InAnonymousNamespace(D);
 164 }
 165
 166 void USRGenerator::VisitDeclContext(DeclContext *DC) {
 167   if (NamedDecl *D = dyn_cast<NamedDecl>(DC))
 168     Visit(D);
 169 }
 170
 171 void USRGenerator::VisitFieldDecl(FieldDecl *D) {
 172   VisitDeclContext(D->getDeclContext());
 173   Out << (isa<ObjCIvarDecl>(D) ? "@" : "@FI@");
 174   if (EmitDeclName(D)) {
 175     // Bit fields can be anonymous.
 176     IgnoreResults = true;
 177     return;
 178   }
 179 }
 180
 181 void USRGenerator::VisitFunctionDecl(FunctionDecl *D) {
 182   if (ShouldGenerateLocation(D) && GenLoc(D))
 183     return;
 184
 185   VisitDeclContext(D->getDeclContext());
 186   if (FunctionTemplateDecl *FunTmpl = D->getDescribedFunctionTemplate()) {
 187     Out << "@FT@";
 188     VisitTemplateParameterList(FunTmpl->getTemplateParameters());
 189   } else
 190     Out << "@F@";
 191   D->printName(Out);
 192
 193   ASTContext &Ctx = AU->getASTContext();
 194   if (!Ctx.getLangOptions().CPlusPlus || D->isExternC())
 195     return;
 196
 197   // Mangle in type information for the arguments.
 198   for (FunctionDecl::param_iterator I = D->param_begin(), E = D->param_end();
 199        I != E; ++I) {
 200     Out << '#';
 201     if (ParmVarDecl *PD = *I)
 202       VisitType(PD->getType());
 203   }
 204   if (D->isVariadic())
 205     Out << '.';
 206   Out << '#';
 207   if (CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(D)) {
 208     if (MD->isStatic())
 209       Out << 'S';
 210     if (unsigned quals = MD->getTypeQualifiers())
 211       Out << (char)('0' + quals);
 212   }
 213 }
 214
 215 void USRGenerator::VisitNamedDecl(NamedDecl *D) {
 216   VisitDeclContext(D->getDeclContext());
 217   Out << "@";
 218
 219   if (EmitDeclName(D)) {
 220     // The string can be empty if the declaration has no name; e.g., it is
 221     // the ParmDecl with no name for declaration of a function pointer type,
 222     // e.g.: void  (*f)(void *);
 223     // In this case, don't generate a USR.
 224     IgnoreResults = true;
 225   }
 226 }
 227
 228 void USRGenerator::VisitVarDecl(VarDecl *D) {
 229   // VarDecls can be declared 'extern' within a function or method body,
 230   // but their enclosing DeclContext is the function, not the TU.  We need
 231   // to check the storage class to correctly generate the USR.
 232   if (ShouldGenerateLocation(D) && GenLoc(D))
 233     return;
 234
 235   VisitDeclContext(D->getDeclContext());
 236
 237   // Variables always have simple names.
 238   llvm::StringRef s = D->getName();
 239
 240   // The string can be empty if the declaration has no name; e.g., it is
 241   // the ParmDecl with no name for declaration of a function pointer type, e.g.:
 242   //    void  (*f)(void *);
 243   // In this case, don't generate a USR.
 244   if (s.empty())
 245     IgnoreResults = true;
 246   else
 247     Out << '@' << s;
 248 }
 249
 250 void USRGenerator::VisitNonTypeTemplateParmDecl(NonTypeTemplateParmDecl *D) {
 251   GenLoc(D);
 252   return;
 253 }
 254
 255 void USRGenerator::VisitTemplateTemplateParmDecl(TemplateTemplateParmDecl *D) {
 256   GenLoc(D);
 257   return;
 258 }
 259
 260 void USRGenerator::VisitNamespaceDecl(NamespaceDecl *D) {
 261   if (D->isAnonymousNamespace()) {
 262     Out << "@aN";
 263     return;
 264   }
 265
 266   VisitDeclContext(D->getDeclContext());
 267   if (!IgnoreResults)
 268     Out << "@N@" << D->getName();
 269 }
 270
 271 void USRGenerator::VisitFunctionTemplateDecl(FunctionTemplateDecl *D) {
 272   VisitFunctionDecl(D->getTemplatedDecl());
 273 }
 274
 275 void USRGenerator::VisitClassTemplateDecl(ClassTemplateDecl *D) {
 276   VisitTagDecl(D->getTemplatedDecl());
 277 }
 278
 279 void USRGenerator::VisitNamespaceAliasDecl(NamespaceAliasDecl *D) {
 280   VisitDeclContext(D->getDeclContext());
 281   if (!IgnoreResults)
 282     Out << "@NA@" << D->getName();
 283 }
 284
 285 void USRGenerator::VisitObjCMethodDecl(ObjCMethodDecl *D) {
 286   DeclContext *container = D->getDeclContext();
 287   if (ObjCProtocolDecl *pd = dyn_cast<ObjCProtocolDecl>(container)) {
 288     Visit(pd);
 289   }
 290   else {
 291     // The USR for a method declared in a class extension or category is based on
 292     // the ObjCInterfaceDecl, not the ObjCCategoryDecl.
 293     ObjCInterfaceDecl *ID = D->getClassInterface();
 294     if (!ID) {
 295       IgnoreResults = true;
 296       return;
 297     }
 298     Visit(ID);
 299   }
 300   // Ideally we would use 'GenObjCMethod', but this is such a hot path
 301   // for Objective-C code that we don't want to use
 302   // DeclarationName::getAsString().
 303   Out << (D->isInstanceMethod() ? "(im)" : "(cm)");
 304   DeclarationName N(D->getSelector());
 305   N.printName(Out);
 306 }
 307
 308 void USRGenerator::VisitObjCClassDecl(ObjCClassDecl *D) {
 309   // FIXME: @class declarations can refer to multiple classes.  We need
 310   //  to be able to traverse these.
 311   IgnoreResults = true;
 312 }
 313
 314 void USRGenerator::VisitObjCForwardProtocolDecl(ObjCForwardProtocolDecl *D) {
 315   // FIXME: @protocol declarations can refer to multiple protocols.  We need
 316   //  to be able to traverse these.
 317   IgnoreResults = true;
 318 }
 319
 320 void USRGenerator::VisitObjCContainerDecl(ObjCContainerDecl *D) {
 321   switch (D->getKind()) {
 322     default:
 323       assert(false && "Invalid ObjC container.");
 324     case Decl::ObjCInterface:
 325     case Decl::ObjCImplementation:
 326       GenObjCClass(D->getName());
 327       break;
 328     case Decl::ObjCCategory: {
 329       ObjCCategoryDecl *CD = cast<ObjCCategoryDecl>(D);
 330       ObjCInterfaceDecl *ID = CD->getClassInterface();
 331       if (!ID) {
 332         // Handle invalid code where the @interface might not
 333         // have been specified.
 334         // FIXME: We should be able to generate this USR even if the
 335         // @interface isn't available.
 336         IgnoreResults = true;
 337         return;
 338       }
 339       // Specially handle class extensions, which are anonymous categories.
 340       // We want to mangle in the location to uniquely distinguish them.
 341       if (CD->IsClassExtension()) {
 342         Out << "objc(ext)" << ID->getName() << '@';
 343         GenLoc(CD);
 344       }
 345       else
 346         GenObjCCategory(ID->getName(), CD->getName());
 347
 348       break;
 349     }
 350     case Decl::ObjCCategoryImpl: {
 351       ObjCCategoryImplDecl *CD = cast<ObjCCategoryImplDecl>(D);
 352       ObjCInterfaceDecl *ID = CD->getClassInterface();
 353       if (!ID) {
 354         // Handle invalid code where the @interface might not
 355         // have been specified.
 356         // FIXME: We should be able to generate this USR even if the
 357         // @interface isn't available.
 358         IgnoreResults = true;
 359         return;
 360       }
 361       GenObjCCategory(ID->getName(), CD->getName());
 362       break;
 363     }
 364     case Decl::ObjCProtocol:
 365       GenObjCProtocol(cast<ObjCProtocolDecl>(D)->getName());
 366       break;
 367   }
 368 }
 369
 370 void USRGenerator::VisitObjCPropertyDecl(ObjCPropertyDecl *D) {
 371   Visit(cast<Decl>(D->getDeclContext()));
 372   GenObjCProperty(D->getName());
 373 }
 374
 375 void USRGenerator::VisitObjCPropertyImplDecl(ObjCPropertyImplDecl *D) {
 376   if (ObjCPropertyDecl *PD = D->getPropertyDecl()) {
 377     VisitObjCPropertyDecl(PD);
 378     return;
 379   }
 380
 381   IgnoreResults = true;
 382 }
 383
 384 void USRGenerator::VisitTagDecl(TagDecl *D) {
 385   // Add the location of the tag decl to handle resolution across
 386   // translation units.
 387   if (ShouldGenerateLocation(D) && GenLoc(D))
 388     return;
 389
 390   D = D->getCanonicalDecl();
 391   VisitDeclContext(D->getDeclContext());
 392
 393   bool AlreadyStarted = false;
 394   if (CXXRecordDecl *CXXRecord = dyn_cast<CXXRecordDecl>(D)) {
 395     if (ClassTemplateDecl *ClassTmpl = CXXRecord->getDescribedClassTemplate()) {
 396       AlreadyStarted = true;
 397
 398       switch (D->getTagKind()) {
 399       case TTK_Struct: Out << "@ST"; break;
 400       case TTK_Class:  Out << "@CT"; break;
 401       case TTK_Union:  Out << "@UT"; break;
 402       case TTK_Enum: llvm_unreachable("enum template"); break;
 403       }
 404       VisitTemplateParameterList(ClassTmpl->getTemplateParameters());
 405     } else if (ClassTemplatePartialSpecializationDecl *PartialSpec
 406                 = dyn_cast<ClassTemplatePartialSpecializationDecl>(CXXRecord)) {
 407       AlreadyStarted = true;
 408
 409       switch (D->getTagKind()) {
 410       case TTK_Struct: Out << "@SP"; break;
 411       case TTK_Class:  Out << "@CP"; break;
 412       case TTK_Union:  Out << "@UP"; break;
 413       case TTK_Enum: llvm_unreachable("enum partial specialization"); break;
 414       }
 415       VisitTemplateParameterList(PartialSpec->getTemplateParameters());
 416     }
 417   }
 418
 419   if (!AlreadyStarted) {
 420     switch (D->getTagKind()) {
 421       case TTK_Struct: Out << "@S"; break;
 422       case TTK_Class:  Out << "@C"; break;
 423       case TTK_Union:  Out << "@U"; break;
 424       case TTK_Enum:   Out << "@E"; break;
 425     }
 426   }
 427
 428   Out << '@';
 429   Out.flush();
 430   assert(Buf.size() > 0);
 431   const unsigned off = Buf.size() - 1;
 432
 433   if (EmitDeclName(D)) {
 434     if (const TypedefDecl *TD = D->getTypedefForAnonDecl()) {
 435       Buf[off] = 'A';
 436       Out << '@' << TD;
 437     }
 438     else
 439       Buf[off] = 'a';
 440   }
 441
 442   // For a class template specialization, mangle the template arguments.
 443   if (ClassTemplateSpecializationDecl *Spec
 444                               = dyn_cast<ClassTemplateSpecializationDecl>(D)) {
 445     const TemplateArgumentList &Args = Spec->getTemplateInstantiationArgs();
 446     Out << '>';
 447     for (unsigned I = 0, N = Args.size(); I != N; ++I) {
 448       Out << '#';
 449       VisitTemplateArgument(Args.get(I));
 450     }
 451   }
 452 }
 453
 454 void USRGenerator::VisitTypedefDecl(TypedefDecl *D) {
 455   if (ShouldGenerateLocation(D) && GenLoc(D))
 456     return;
 457   DeclContext *DC = D->getDeclContext();
 458   if (NamedDecl *DCN = dyn_cast<NamedDecl>(DC))
 459     Visit(DCN);
 460   Out << "@T@";
 461   Out << D->getName();
 462 }
 463
 464 void USRGenerator::VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D) {
 465   GenLoc(D);
 466   return;
 467 }
 468
 469 bool USRGenerator::GenLoc(const Decl *D) {
 470   if (generatedLoc)
 471     return IgnoreResults;
 472   generatedLoc = true;
 473
 474   const SourceManager &SM = AU->getSourceManager();
 475   SourceLocation L = D->getLocStart();
 476   if (L.isInvalid()) {
 477     IgnoreResults = true;
 478     return true;
 479   }
 480   L = SM.getInstantiationLoc(L);
 481   const std::pair<FileID, unsigned> &Decomposed = SM.getDecomposedLoc(L);
 482   const FileEntry *FE = SM.getFileEntryForID(Decomposed.first);
 483   if (FE) {
 484     Out << llvm::sys::path::filename(FE->getName());
 485   }
 486   else {
 487     // This case really isn't interesting.
 488     IgnoreResults = true;
 489     return true;
 490   }
 491   // Use the offest into the FileID to represent the location.  Using
 492   // a line/column can cause us to look back at the original source file,
 493   // which is expensive.
 494   Out << '@' << Decomposed.second;
 495   return IgnoreResults;
 496 }
 497
 498 void USRGenerator::VisitType(QualType T) {
 499   // This method mangles in USR information for types.  It can possibly
 500   // just reuse the naming-mangling logic used by codegen, although the
 501   // requirements for USRs might not be the same.
 502   ASTContext &Ctx = AU->getASTContext();
 503
 504   do {
 505     T = Ctx.getCanonicalType(T);
 506     Qualifiers Q = T.getQualifiers();
 507     unsigned qVal = 0;
 508     if (Q.hasConst())
 509       qVal |= 0x1;
 510     if (Q.hasVolatile())
 511       qVal |= 0x2;
 512     if (Q.hasRestrict())
 513       qVal |= 0x4;
 514     if(qVal)
 515       Out << ((char) ('0' + qVal));
 516
 517     // Mangle in ObjC GC qualifiers?
 518
 519     if (const PackExpansionType *Expansion = T->getAs<PackExpansionType>()) {
 520       Out << 'P';
 521       T = Expansion->getPattern();
 522     }
 523
 524     if (const BuiltinType *BT = T->getAs<BuiltinType>()) {
 525       unsigned char c = '\0';
 526       switch (BT->getKind()) {
 527         case BuiltinType::Void:
 528           c = 'v'; break;
 529         case BuiltinType::Bool:
 530           c = 'b'; break;
 531         case BuiltinType::Char_U:
 532         case BuiltinType::UChar:
 533           c = 'c'; break;
 534         case BuiltinType::Char16:
 535           c = 'q'; break;
 536         case BuiltinType::Char32:
 537           c = 'w'; break;
 538         case BuiltinType::UShort:
 539           c = 's'; break;
 540         case BuiltinType::UInt:
 541           c = 'i'; break;
 542         case BuiltinType::ULong:
 543           c = 'l'; break;
 544         case BuiltinType::ULongLong:
 545           c = 'k'; break;
 546         case BuiltinType::UInt128:
 547           c = 'j'; break;
 548         case BuiltinType::Char_S:
 549         case BuiltinType::SChar:
 550           c = 'C'; break;
 551         case BuiltinType::WChar_S:
 552         case BuiltinType::WChar_U:
 553           c = 'W'; break;
 554         case BuiltinType::Short:
 555           c = 'S'; break;
 556         case BuiltinType::Int:
 557           c = 'I'; break;
 558         case BuiltinType::Long:
 559           c = 'L'; break;
 560         case BuiltinType::LongLong:
 561           c = 'K'; break;
 562         case BuiltinType::Int128:
 563           c = 'J'; break;
 564         case BuiltinType::Float:
 565           c = 'f'; break;
 566         case BuiltinType::Double:
 567           c = 'd'; break;
 568         case BuiltinType::LongDouble:
 569           c = 'D'; break;
 570         case BuiltinType::NullPtr:
 571           c = 'n'; break;
 572         case BuiltinType::Overload:
 573         case BuiltinType::Dependent:
 574         case BuiltinType::UndeducedAuto:
 575           IgnoreResults = true;
 576           return;
 577         case BuiltinType::ObjCId:
 578           c = 'o'; break;
 579         case BuiltinType::ObjCClass:
 580           c = 'O'; break;
 581         case BuiltinType::ObjCSel:
 582           c = 'e'; break;
 583       }
 584       Out << c;
 585       return;
 586     }
 587
 588     // If we have already seen this (non-built-in) type, use a substitution
 589     // encoding.
 590     llvm::DenseMap<const Type *, unsigned>::iterator Substitution
 591       = TypeSubstitutions.find(T.getTypePtr());
 592     if (Substitution != TypeSubstitutions.end()) {
 593       Out << 'S' << Substitution->second << '_';
 594       return;
 595     } else {
 596       // Record this as a substitution.
 597       unsigned Number = TypeSubstitutions.size();
 598       TypeSubstitutions[T.getTypePtr()] = Number;
 599     }
 600
 601     if (const PointerType *PT = T->getAs<PointerType>()) {
 602       Out << '*';
 603       T = PT->getPointeeType();
 604       continue;
 605     }
 606     if (const ReferenceType *RT = T->getAs<ReferenceType>()) {
 607       Out << '&';
 608       T = RT->getPointeeType();
 609       continue;
 610     }
 611     if (const FunctionProtoType *FT = T->getAs<FunctionProtoType>()) {
 612       Out << 'F';
 613       VisitType(FT->getResultType());
 614       for (FunctionProtoType::arg_type_iterator
 615             I = FT->arg_type_begin(), E = FT->arg_type_end(); I!=E; ++I) {
 616         VisitType(*I);
 617       }
 618       if (FT->isVariadic())
 619         Out << '.';
 620       return;
 621     }
 622     if (const BlockPointerType *BT = T->getAs<BlockPointerType>()) {
 623       Out << 'B';
 624       T = BT->getPointeeType();
 625       continue;
 626     }
 627     if (const ComplexType *CT = T->getAs<ComplexType>()) {
 628       Out << '<';
 629       T = CT->getElementType();
 630       continue;
 631     }
 632     if (const TagType *TT = T->getAs<TagType>()) {
 633       Out << '$';
 634       VisitTagDecl(TT->getDecl());
 635       return;
 636     }
 637     if (const TemplateTypeParmType *TTP = T->getAs<TemplateTypeParmType>()) {
 638       Out << 't' << TTP->getDepth() << '.' << TTP->getIndex();
 639       return;
 640     }
 641     if (const TemplateSpecializationType *Spec
 642                                     = T->getAs<TemplateSpecializationType>()) {
 643       Out << '>';
 644       VisitTemplateName(Spec->getTemplateName());
 645       Out << Spec->getNumArgs();
 646       for (unsigned I = 0, N = Spec->getNumArgs(); I != N; ++I)
 647         VisitTemplateArgument(Spec->getArg(I));
 648       return;
 649     }
 650
 651     // Unhandled type.
 652     Out << ' ';
 653     break;
 654   } while (true);
 655 }
 656
 657 void USRGenerator::VisitTemplateParameterList(
 658                                          const TemplateParameterList *Params) {
 659   if (!Params)
 660     return;
 661   Out << '>' << Params->size();
 662   for (TemplateParameterList::const_iterator P = Params->begin(),
 663                                           PEnd = Params->end();
 664        P != PEnd; ++P) {
 665     Out << '#';
 666     if (isa<TemplateTypeParmDecl>(*P)) {
 667       if (cast<TemplateTypeParmDecl>(*P)->isParameterPack())
 668         Out<< 'p';
 669       Out << 'T';
 670       continue;
 671     }
 672
 673     if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(*P)) {
 674       if (NTTP->isParameterPack())
 675         Out << 'p';
 676       Out << 'N';
 677       VisitType(NTTP->getType());
 678       continue;
 679     }
 680
 681     TemplateTemplateParmDecl *TTP = cast<TemplateTemplateParmDecl>(*P);
 682     if (TTP->isParameterPack())
 683       Out << 'p';
 684     Out << 't';
 685     VisitTemplateParameterList(TTP->getTemplateParameters());
 686   }
 687 }
 688
 689 void USRGenerator::VisitTemplateName(TemplateName Name) {
 690   if (TemplateDecl *Template = Name.getAsTemplateDecl()) {
 691     if (TemplateTemplateParmDecl *TTP
 692                               = dyn_cast<TemplateTemplateParmDecl>(Template)) {
 693       Out << 't' << TTP->getDepth() << '.' << TTP->getIndex();
 694       return;
 695     }
 696
 697     Visit(Template);
 698     return;
 699   }
 700
 701   // FIXME: Visit dependent template names.
 702 }
 703
 704 void USRGenerator::VisitTemplateArgument(const TemplateArgument &Arg) {
 705   switch (Arg.getKind()) {
 706   case TemplateArgument::Null:
 707     break;
 708
 709   case TemplateArgument::Declaration:
 710     if (Decl *D = Arg.getAsDecl())
 711       Visit(D);
 712     break;
 713
 714   case TemplateArgument::TemplateExpansion:
 715     Out << 'P'; // pack expansion of...
 716     // Fall through
 717   case TemplateArgument::Template:
 718     VisitTemplateName(Arg.getAsTemplateOrTemplatePattern());
 719     break;
 720
 721   case TemplateArgument::Expression:
 722     // FIXME: Visit expressions.
 723     break;
 724
 725   case TemplateArgument::Pack:
 726     Out << 'p' << Arg.pack_size();
 727     for (TemplateArgument::pack_iterator P = Arg.pack_begin(), PEnd = Arg.pack_end();
 728          P != PEnd; ++P)
 729       VisitTemplateArgument(*P);
 730     break;
 731
 732   case TemplateArgument::Type:
 733     VisitType(Arg.getAsType());
 734     break;
 735
 736   case TemplateArgument::Integral:
 737     Out << 'V';
 738     VisitType(Arg.getIntegralType());
 739     Out << *Arg.getAsIntegral();
 740     break;
 741   }
 742 }
 743
 744 //===----------------------------------------------------------------------===//
 745 // General purpose USR generation methods.
 746 //===----------------------------------------------------------------------===//
 747
 748 void USRGenerator::GenObjCClass(llvm::StringRef cls) {
 749   Out << "objc(cs)" << cls;
 750 }
 751
 752 void USRGenerator::GenObjCCategory(llvm::StringRef cls, llvm::StringRef cat) {
 753   Out << "objc(cy)" << cls << '@' << cat;
 754 }
 755
 756 void USRGenerator::GenObjCIvar(llvm::StringRef ivar) {
 757   Out << '@' << ivar;
 758 }
 759
 760 void USRGenerator::GenObjCMethod(llvm::StringRef meth, bool isInstanceMethod) {
 761   Out << (isInstanceMethod ? "(im)" : "(cm)") << meth;
 762 }
 763
 764 void USRGenerator::GenObjCProperty(llvm::StringRef prop) {
 765   Out << "(py)" << prop;
 766 }
 767
 768 void USRGenerator::GenObjCProtocol(llvm::StringRef prot) {
 769   Out << "objc(pl)" << prot;
 770 }
 771
 772 //===----------------------------------------------------------------------===//
 773 // API hooks.
 774 //===----------------------------------------------------------------------===//
 775
 776 static inline llvm::StringRef extractUSRSuffix(llvm::StringRef s) {
 777   return s.startswith("c:") ? s.substr(2) : "";
 778 }
 779
 780 static CXString getDeclCursorUSR(const CXCursor &C) {
 781   Decl *D = cxcursor::getCursorDecl(C);
 782
 783   // Don't generate USRs for things with invalid locations.
 784   if (!D || D->getLocStart().isInvalid())
 785     return createCXString("");
 786
 787   // Check if the cursor has 'NoLinkage'.
 788   if (const NamedDecl *ND = dyn_cast<NamedDecl>(D))
 789     switch (ND->getLinkage()) {
 790       case ExternalLinkage:
 791         // Generate USRs for all entities with external linkage.
 792         break;
 793       case NoLinkage:
 794       case UniqueExternalLinkage:
 795         // We allow enums, typedefs, and structs that have no linkage to
 796         // have USRs that are anchored to the file they were defined in
 797         // (e.g., the header).  This is a little gross, but in principal
 798         // enums/anonymous structs/etc. defined in a common header file
 799         // are referred to across multiple translation units.
 800         if (isa<TagDecl>(ND) || isa<TypedefDecl>(ND) ||
 801             isa<EnumConstantDecl>(ND) || isa<FieldDecl>(ND) ||
 802             isa<VarDecl>(ND) || isa<NamespaceDecl>(ND))
 803           break;
 804         // Fall-through.
 805       case InternalLinkage:
 806         if (isa<FunctionDecl>(ND))
 807           break;
 808     }
 809
 810   CXTranslationUnit TU = cxcursor::getCursorTU(C);
 811   if (!TU)
 812     return createCXString("");
 813
 814   CXStringBuf *buf = cxstring::getCXStringBuf(TU);
 815   if (!buf)
 816     return createCXString("");
 817
 818   {
 819     USRGenerator UG(&C, &buf->Data);
 820     UG->Visit(D);
 821
 822     if (UG->ignoreResults()) {
 823       disposeCXStringBuf(buf);
 824       return createCXString("");
 825     }
 826   }
 827   // Return the C-string, but don't make a copy since it is already in
 828   // the string buffer.
 829   buf->Data.push_back('\0');
 830   return createCXString(buf);
 831 }
 832
 833 extern "C" {
 834
 835 CXString clang_getCursorUSR(CXCursor C) {
 836   const CXCursorKind &K = clang_getCursorKind(C);
 837
 838   if (clang_isDeclaration(K))
 839       return getDeclCursorUSR(C);
 840
 841   if (K == CXCursor_MacroDefinition) {
 842     CXTranslationUnit TU = cxcursor::getCursorTU(C);
 843     if (!TU)
 844       return createCXString("");
 845
 846     CXStringBuf *buf = cxstring::getCXStringBuf(TU);
 847     if (!buf)
 848       return createCXString("");
 849
 850     {
 851       USRGenerator UG(&C, &buf->Data);
 852       UG << "macro@"
 853         << cxcursor::getCursorMacroDefinition(C)->getName()->getNameStart();
 854     }
 855     buf->Data.push_back('\0');
 856     return createCXString(buf);
 857   }
 858
 859   return createCXString("");
 860 }
 861
 862 CXString clang_constructUSR_ObjCIvar(const char *name, CXString classUSR) {
 863   USRGenerator UG;
 864   UG << extractUSRSuffix(clang_getCString(classUSR));
 865   UG->GenObjCIvar(name);
 866   return createCXString(UG.str(), true);
 867 }
 868
 869 CXString clang_constructUSR_ObjCMethod(const char *name,
 870                                        unsigned isInstanceMethod,
 871                                        CXString classUSR) {
 872   USRGenerator UG;
 873   UG << extractUSRSuffix(clang_getCString(classUSR));
 874   UG->GenObjCMethod(name, isInstanceMethod);
 875   return createCXString(UG.str(), true);
 876 }
 877
 878 CXString clang_constructUSR_ObjCClass(const char *name) {
 879   USRGenerator UG;
 880   UG->GenObjCClass(name);
 881   return createCXString(UG.str(), true);
 882 }
 883
 884 CXString clang_constructUSR_ObjCProtocol(const char *name) {
 885   USRGenerator UG;
 886   UG->GenObjCProtocol(name);
 887   return createCXString(UG.str(), true);
 888 }
 889
 890 CXString clang_constructUSR_ObjCCategory(const char *class_name,
 891                                          const char *category_name) {
 892   USRGenerator UG;
 893   UG->GenObjCCategory(class_name, category_name);
 894   return createCXString(UG.str(), true);
 895 }
 896
 897 CXString clang_constructUSR_ObjCProperty(const char *property,
 898                                          CXString classUSR) {
 899   USRGenerator UG;
 900   UG << extractUSRSuffix(clang_getCString(classUSR));
 901   UG->GenObjCProperty(property);
 902   return createCXString(UG.str(), true);
 903 }
 904
 905 } // end extern "C"