CIndexUSRs.cpp revision d7a6b1640e565487d163023a6a2e83f55476ae96 
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
24using namespace clang;
25using namespace clang::cxstring;
26
27//===----------------------------------------------------------------------===//
28// USR generation.
29//===----------------------------------------------------------------------===//
30
31namespace {
32class USRGenerator : public DeclVisitor<USRGenerator> {
33  OwningPtr<SmallString<128> > OwnedBuf;
34  SmallVectorImpl<char> &Buf;
35  llvm::raw_svector_ostream Out;
36  bool IgnoreResults;
37  ASTContext *Context;
38  bool generatedLoc;
39
40  llvm::DenseMap<const Type *, unsigned> TypeSubstitutions;
41
42public:
43  explicit USRGenerator(ASTContext *Ctx = 0, SmallVectorImpl<char> *extBuf = 0)
44  : OwnedBuf(extBuf ? 0 : new SmallString<128>()),
45    Buf(extBuf ? *extBuf : *OwnedBuf.get()),
46    Out(Buf),
47    IgnoreResults(false),
48    Context(Ctx),
49    generatedLoc(false)
50  {
51    // Add the USR space prefix.
52    Out << "c:";
53  }
54
55  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 VisitObjCContainerDecl(ObjCContainerDecl *CD);
79  void VisitObjCMethodDecl(ObjCMethodDecl *MD);
80  void VisitObjCPropertyDecl(ObjCPropertyDecl *D);
81  void VisitObjCPropertyImplDecl(ObjCPropertyImplDecl *D);
82  void VisitTagDecl(TagDecl *D);
83  void VisitTypedefDecl(TypedefDecl *D);
84  void VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D);
85  void VisitVarDecl(VarDecl *D);
86  void VisitNonTypeTemplateParmDecl(NonTypeTemplateParmDecl *D);
87  void VisitTemplateTemplateParmDecl(TemplateTemplateParmDecl *D);
88  void VisitLinkageSpecDecl(LinkageSpecDecl *D) {
89    IgnoreResults = true;
90  }
91  void VisitUsingDirectiveDecl(UsingDirectiveDecl *D) {
92    IgnoreResults = true;
93  }
94  void VisitUsingDecl(UsingDecl *D) {
95    IgnoreResults = true;
96  }
97  void VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D) {
98    IgnoreResults = true;
99  }
100  void VisitUnresolvedUsingTypenameDecl(UnresolvedUsingTypenameDecl *D) {
101    IgnoreResults = true;
102  }
103
104  /// Generate the string component containing the location of the
105  ///  declaration.
106  bool GenLoc(const Decl *D);
107
108  /// String generation methods used both by the visitation methods
109  /// and from other clients that want to directly generate USRs.  These
110  /// methods do not construct complete USRs (which incorporate the parents
111  /// of an AST element), but only the fragments concerning the AST element
112  /// itself.
113
114  /// Generate a USR for an Objective-C class.
115  void GenObjCClass(StringRef cls);
116  /// Generate a USR for an Objective-C class category.
117  void GenObjCCategory(StringRef cls, StringRef cat);
118  /// Generate a USR fragment for an Objective-C instance variable.  The
119  /// complete USR can be created by concatenating the USR for the
120  /// encompassing class with this USR fragment.
121  void GenObjCIvar(StringRef ivar);
122  /// Generate a USR fragment for an Objective-C method.
123  void GenObjCMethod(StringRef sel, bool isInstanceMethod);
124  /// Generate a USR fragment for an Objective-C property.
125  void GenObjCProperty(StringRef prop);
126  /// Generate a USR for an Objective-C protocol.
127  void GenObjCProtocol(StringRef prot);
128
129  void VisitType(QualType T);
130  void VisitTemplateParameterList(const TemplateParameterList *Params);
131  void VisitTemplateName(TemplateName Name);
132  void VisitTemplateArgument(const TemplateArgument &Arg);
133
134  /// Emit a Decl's name using NamedDecl::printName() and return true if
135  ///  the decl had no name.
136  bool EmitDeclName(const NamedDecl *D);
137};
138
139} // end anonymous namespace
140
141//===----------------------------------------------------------------------===//
142// Generating USRs from ASTS.
143//===----------------------------------------------------------------------===//
144
145bool USRGenerator::EmitDeclName(const NamedDecl *D) {
146  Out.flush();
147  const unsigned startSize = Buf.size();
148  D->printName(Out);
149  Out.flush();
150  const unsigned endSize = Buf.size();
151  return startSize == endSize;
152}
153
154static bool InAnonymousNamespace(const Decl *D) {
155  if (const NamespaceDecl *ND = dyn_cast<NamespaceDecl>(D->getDeclContext()))
156    return ND->isAnonymousNamespace();
157  return false;
158}
159
160static inline bool ShouldGenerateLocation(const NamedDecl *D) {
161  return D->getLinkage() != ExternalLinkage && !InAnonymousNamespace(D);
162}
163
164void USRGenerator::VisitDeclContext(DeclContext *DC) {
165  if (NamedDecl *D = dyn_cast<NamedDecl>(DC))
166    Visit(D);
167}
168
169void USRGenerator::VisitFieldDecl(FieldDecl *D) {
170  // The USR for an ivar declared in a class extension is based on the
171  // ObjCInterfaceDecl, not the ObjCCategoryDecl.
172  if (ObjCInterfaceDecl *ID = Context->getObjContainingInterface(D))
173    Visit(ID);
174  else
175    VisitDeclContext(D->getDeclContext());
176  Out << (isa<ObjCIvarDecl>(D) ? "@" : "@FI@");
177  if (EmitDeclName(D)) {
178    // Bit fields can be anonymous.
179    IgnoreResults = true;
180    return;
181  }
182}
183
184void USRGenerator::VisitFunctionDecl(FunctionDecl *D) {
185  if (ShouldGenerateLocation(D) && GenLoc(D))
186    return;
187
188  VisitDeclContext(D->getDeclContext());
189  if (FunctionTemplateDecl *FunTmpl = D->getDescribedFunctionTemplate()) {
190    Out << "@FT@";
191    VisitTemplateParameterList(FunTmpl->getTemplateParameters());
192  } else
193    Out << "@F@";
194  D->printName(Out);
195
196  ASTContext &Ctx = *Context;
197  if (!Ctx.getLangOpts().CPlusPlus || D->isExternC())
198    return;
199
200  if (const TemplateArgumentList *
201        SpecArgs = D->getTemplateSpecializationArgs()) {
202    Out << '<';
203    for (unsigned I = 0, N = SpecArgs->size(); I != N; ++I) {
204      Out << '#';
205      VisitTemplateArgument(SpecArgs->get(I));
206    }
207    Out << '>';
208  }
209
210  // Mangle in type information for the arguments.
211  for (FunctionDecl::param_iterator I = D->param_begin(), E = D->param_end();
212       I != E; ++I) {
213    Out << '#';
214    if (ParmVarDecl *PD = *I)
215      VisitType(PD->getType());
216  }
217  if (D->isVariadic())
218    Out << '.';
219  Out << '#';
220  if (CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(D)) {
221    if (MD->isStatic())
222      Out << 'S';
223    if (unsigned quals = MD->getTypeQualifiers())
224      Out << (char)('0' + quals);
225  }
226}
227
228void USRGenerator::VisitNamedDecl(NamedDecl *D) {
229  VisitDeclContext(D->getDeclContext());
230  Out << "@";
231
232  if (EmitDeclName(D)) {
233    // The string can be empty if the declaration has no name; e.g., it is
234    // the ParmDecl with no name for declaration of a function pointer type,
235    // e.g.: void  (*f)(void *);
236    // In this case, don't generate a USR.
237    IgnoreResults = true;
238  }
239}
240
241void USRGenerator::VisitVarDecl(VarDecl *D) {
242  // VarDecls can be declared 'extern' within a function or method body,
243  // but their enclosing DeclContext is the function, not the TU.  We need
244  // to check the storage class to correctly generate the USR.
245  if (ShouldGenerateLocation(D) && GenLoc(D))
246    return;
247
248  VisitDeclContext(D->getDeclContext());
249
250  // Variables always have simple names.
251  StringRef s = D->getName();
252
253  // The string can be empty if the declaration has no name; e.g., it is
254  // the ParmDecl with no name for declaration of a function pointer type, e.g.:
255  //    void  (*f)(void *);
256  // In this case, don't generate a USR.
257  if (s.empty())
258    IgnoreResults = true;
259  else
260    Out << '@' << s;
261}
262
263void USRGenerator::VisitNonTypeTemplateParmDecl(NonTypeTemplateParmDecl *D) {
264  GenLoc(D);
265  return;
266}
267
268void USRGenerator::VisitTemplateTemplateParmDecl(TemplateTemplateParmDecl *D) {
269  GenLoc(D);
270  return;
271}
272
273void USRGenerator::VisitNamespaceDecl(NamespaceDecl *D) {
274  if (D->isAnonymousNamespace()) {
275    Out << "@aN";
276    return;
277  }
278
279  VisitDeclContext(D->getDeclContext());
280  if (!IgnoreResults)
281    Out << "@N@" << D->getName();
282}
283
284void USRGenerator::VisitFunctionTemplateDecl(FunctionTemplateDecl *D) {
285  VisitFunctionDecl(D->getTemplatedDecl());
286}
287
288void USRGenerator::VisitClassTemplateDecl(ClassTemplateDecl *D) {
289  VisitTagDecl(D->getTemplatedDecl());
290}
291
292void USRGenerator::VisitNamespaceAliasDecl(NamespaceAliasDecl *D) {
293  VisitDeclContext(D->getDeclContext());
294  if (!IgnoreResults)
295    Out << "@NA@" << D->getName();
296}
297
298void USRGenerator::VisitObjCMethodDecl(ObjCMethodDecl *D) {
299  DeclContext *container = D->getDeclContext();
300  if (ObjCProtocolDecl *pd = dyn_cast<ObjCProtocolDecl>(container)) {
301    Visit(pd);
302  }
303  else {
304    // The USR for a method declared in a class extension or category is based on
305    // the ObjCInterfaceDecl, not the ObjCCategoryDecl.
306    ObjCInterfaceDecl *ID = D->getClassInterface();
307    if (!ID) {
308      IgnoreResults = true;
309      return;
310    }
311    Visit(ID);
312  }
313  // Ideally we would use 'GenObjCMethod', but this is such a hot path
314  // for Objective-C code that we don't want to use
315  // DeclarationName::getAsString().
316  Out << (D->isInstanceMethod() ? "(im)" : "(cm)");
317  DeclarationName N(D->getSelector());
318  N.printName(Out);
319}
320
321void USRGenerator::VisitObjCContainerDecl(ObjCContainerDecl *D) {
322  switch (D->getKind()) {
323    default:
324      llvm_unreachable("Invalid ObjC container.");
325    case Decl::ObjCInterface:
326    case Decl::ObjCImplementation:
327      GenObjCClass(D->getName());
328      break;
329    case Decl::ObjCCategory: {
330      ObjCCategoryDecl *CD = cast<ObjCCategoryDecl>(D);
331      ObjCInterfaceDecl *ID = CD->getClassInterface();
332      if (!ID) {
333        // Handle invalid code where the @interface might not
334        // have been specified.
335        // FIXME: We should be able to generate this USR even if the
336        // @interface isn't available.
337        IgnoreResults = true;
338        return;
339      }
340      // Specially handle class extensions, which are anonymous categories.
341      // We want to mangle in the location to uniquely distinguish them.
342      if (CD->IsClassExtension()) {
343        Out << "objc(ext)" << ID->getName() << '@';
344        GenLoc(CD);
345      }
346      else
347        GenObjCCategory(ID->getName(), CD->getName());
348
349      break;
350    }
351    case Decl::ObjCCategoryImpl: {
352      ObjCCategoryImplDecl *CD = cast<ObjCCategoryImplDecl>(D);
353      ObjCInterfaceDecl *ID = CD->getClassInterface();
354      if (!ID) {
355        // Handle invalid code where the @interface might not
356        // have been specified.
357        // FIXME: We should be able to generate this USR even if the
358        // @interface isn't available.
359        IgnoreResults = true;
360        return;
361      }
362      GenObjCCategory(ID->getName(), CD->getName());
363      break;
364    }
365    case Decl::ObjCProtocol:
366      GenObjCProtocol(cast<ObjCProtocolDecl>(D)->getName());
367      break;
368  }
369}
370
371void USRGenerator::VisitObjCPropertyDecl(ObjCPropertyDecl *D) {
372  // The USR for a property declared in a class extension or category is based
373  // on the ObjCInterfaceDecl, not the ObjCCategoryDecl.
374  if (ObjCInterfaceDecl *ID = Context->getObjContainingInterface(D))
375    Visit(ID);
376  else
377    Visit(cast<Decl>(D->getDeclContext()));
378  GenObjCProperty(D->getName());
379}
380
381void USRGenerator::VisitObjCPropertyImplDecl(ObjCPropertyImplDecl *D) {
382  if (ObjCPropertyDecl *PD = D->getPropertyDecl()) {
383    VisitObjCPropertyDecl(PD);
384    return;
385  }
386
387  IgnoreResults = true;
388}
389
390void USRGenerator::VisitTagDecl(TagDecl *D) {
391  // Add the location of the tag decl to handle resolution across
392  // translation units.
393  if (ShouldGenerateLocation(D) && GenLoc(D))
394    return;
395
396  D = D->getCanonicalDecl();
397  VisitDeclContext(D->getDeclContext());
398
399  bool AlreadyStarted = false;
400  if (CXXRecordDecl *CXXRecord = dyn_cast<CXXRecordDecl>(D)) {
401    if (ClassTemplateDecl *ClassTmpl = CXXRecord->getDescribedClassTemplate()) {
402      AlreadyStarted = true;
403
404      switch (D->getTagKind()) {
405      case TTK_Interface:
406      case TTK_Struct: Out << "@ST"; break;
407      case TTK_Class:  Out << "@CT"; break;
408      case TTK_Union:  Out << "@UT"; break;
409      case TTK_Enum: llvm_unreachable("enum template");
410      }
411      VisitTemplateParameterList(ClassTmpl->getTemplateParameters());
412    } else if (ClassTemplatePartialSpecializationDecl *PartialSpec
413                = dyn_cast<ClassTemplatePartialSpecializationDecl>(CXXRecord)) {
414      AlreadyStarted = true;
415
416      switch (D->getTagKind()) {
417      case TTK_Interface:
418      case TTK_Struct: Out << "@SP"; break;
419      case TTK_Class:  Out << "@CP"; break;
420      case TTK_Union:  Out << "@UP"; break;
421      case TTK_Enum: llvm_unreachable("enum partial specialization");
422      }
423      VisitTemplateParameterList(PartialSpec->getTemplateParameters());
424    }
425  }
426
427  if (!AlreadyStarted) {
428    switch (D->getTagKind()) {
429      case TTK_Interface:
430      case TTK_Struct: Out << "@S"; break;
431      case TTK_Class:  Out << "@C"; break;
432      case TTK_Union:  Out << "@U"; break;
433      case TTK_Enum:   Out << "@E"; break;
434    }
435  }
436
437  Out << '@';
438  Out.flush();
439  assert(Buf.size() > 0);
440  const unsigned off = Buf.size() - 1;
441
442  if (EmitDeclName(D)) {
443    if (const TypedefNameDecl *TD = D->getTypedefNameForAnonDecl()) {
444      Buf[off] = 'A';
445      Out << '@' << *TD;
446    }
447    else
448      Buf[off] = 'a';
449  }
450
451  // For a class template specialization, mangle the template arguments.
452  if (ClassTemplateSpecializationDecl *Spec
453                              = dyn_cast<ClassTemplateSpecializationDecl>(D)) {
454    const TemplateArgumentList &Args = Spec->getTemplateInstantiationArgs();
455    Out << '>';
456    for (unsigned I = 0, N = Args.size(); I != N; ++I) {
457      Out << '#';
458      VisitTemplateArgument(Args.get(I));
459    }
460  }
461}
462
463void USRGenerator::VisitTypedefDecl(TypedefDecl *D) {
464  if (ShouldGenerateLocation(D) && GenLoc(D))
465    return;
466  DeclContext *DC = D->getDeclContext();
467  if (NamedDecl *DCN = dyn_cast<NamedDecl>(DC))
468    Visit(DCN);
469  Out << "@T@";
470  Out << D->getName();
471}
472
473void USRGenerator::VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D) {
474  GenLoc(D);
475  return;
476}
477
478bool USRGenerator::GenLoc(const Decl *D) {
479  if (generatedLoc)
480    return IgnoreResults;
481  generatedLoc = true;
482
483  // Guard against null declarations in invalid code.
484  if (!D) {
485    IgnoreResults = true;
486    return true;
487  }
488
489  // Use the location of canonical decl.
490  D = D->getCanonicalDecl();
491
492  const SourceManager &SM = Context->getSourceManager();
493  SourceLocation L = D->getLocStart();
494  if (L.isInvalid()) {
495    IgnoreResults = true;
496    return true;
497  }
498  L = SM.getExpansionLoc(L);
499  const std::pair<FileID, unsigned> &Decomposed = SM.getDecomposedLoc(L);
500  const FileEntry *FE = SM.getFileEntryForID(Decomposed.first);
501  if (FE) {
502    Out << llvm::sys::path::filename(FE->getName());
503  }
504  else {
505    // This case really isn't interesting.
506    IgnoreResults = true;
507    return true;
508  }
509  // Use the offest into the FileID to represent the location.  Using
510  // a line/column can cause us to look back at the original source file,
511  // which is expensive.
512  Out << '@' << Decomposed.second;
513  return IgnoreResults;
514}
515
516void USRGenerator::VisitType(QualType T) {
517  // This method mangles in USR information for types.  It can possibly
518  // just reuse the naming-mangling logic used by codegen, although the
519  // requirements for USRs might not be the same.
520  ASTContext &Ctx = *Context;
521
522  do {
523    T = Ctx.getCanonicalType(T);
524    Qualifiers Q = T.getQualifiers();
525    unsigned qVal = 0;
526    if (Q.hasConst())
527      qVal |= 0x1;
528    if (Q.hasVolatile())
529      qVal |= 0x2;
530    if (Q.hasRestrict())
531      qVal |= 0x4;
532    if(qVal)
533      Out << ((char) ('0' + qVal));
534
535    // Mangle in ObjC GC qualifiers?
536
537    if (const PackExpansionType *Expansion = T->getAs<PackExpansionType>()) {
538      Out << 'P';
539      T = Expansion->getPattern();
540    }
541
542    if (const BuiltinType *BT = T->getAs<BuiltinType>()) {
543      unsigned char c = '\0';
544      switch (BT->getKind()) {
545        case BuiltinType::Void:
546          c = 'v'; break;
547        case BuiltinType::Bool:
548          c = 'b'; break;
549        case BuiltinType::Char_U:
550        case BuiltinType::UChar:
551          c = 'c'; break;
552        case BuiltinType::Char16:
553          c = 'q'; break;
554        case BuiltinType::Char32:
555          c = 'w'; break;
556        case BuiltinType::UShort:
557          c = 's'; break;
558        case BuiltinType::UInt:
559          c = 'i'; break;
560        case BuiltinType::ULong:
561          c = 'l'; break;
562        case BuiltinType::ULongLong:
563          c = 'k'; break;
564        case BuiltinType::UInt128:
565          c = 'j'; break;
566        case BuiltinType::Char_S:
567        case BuiltinType::SChar:
568          c = 'C'; break;
569        case BuiltinType::WChar_S:
570        case BuiltinType::WChar_U:
571          c = 'W'; break;
572        case BuiltinType::Short:
573          c = 'S'; break;
574        case BuiltinType::Int:
575          c = 'I'; break;
576        case BuiltinType::Long:
577          c = 'L'; break;
578        case BuiltinType::LongLong:
579          c = 'K'; break;
580        case BuiltinType::Int128:
581          c = 'J'; break;
582        case BuiltinType::Half:
583          c = 'h'; break;
584        case BuiltinType::Float:
585          c = 'f'; break;
586        case BuiltinType::Double:
587          c = 'd'; break;
588        case BuiltinType::LongDouble:
589          c = 'D'; break;
590        case BuiltinType::NullPtr:
591          c = 'n'; break;
592#define BUILTIN_TYPE(Id, SingletonId)
593#define PLACEHOLDER_TYPE(Id, SingletonId) case BuiltinType::Id:
594#include "clang/AST/BuiltinTypes.def"
595        case BuiltinType::Dependent:
596          IgnoreResults = true;
597          return;
598        case BuiltinType::ObjCId:
599          c = 'o'; break;
600        case BuiltinType::ObjCClass:
601          c = 'O'; break;
602        case BuiltinType::ObjCSel:
603          c = 'e'; break;
604      }
605      Out << c;
606      return;
607    }
608
609    // If we have already seen this (non-built-in) type, use a substitution
610    // encoding.
611    llvm::DenseMap<const Type *, unsigned>::iterator Substitution
612      = TypeSubstitutions.find(T.getTypePtr());
613    if (Substitution != TypeSubstitutions.end()) {
614      Out << 'S' << Substitution->second << '_';
615      return;
616    } else {
617      // Record this as a substitution.
618      unsigned Number = TypeSubstitutions.size();
619      TypeSubstitutions[T.getTypePtr()] = Number;
620    }
621
622    if (const PointerType *PT = T->getAs<PointerType>()) {
623      Out << '*';
624      T = PT->getPointeeType();
625      continue;
626    }
627    if (const ReferenceType *RT = T->getAs<ReferenceType>()) {
628      Out << '&';
629      T = RT->getPointeeType();
630      continue;
631    }
632    if (const FunctionProtoType *FT = T->getAs<FunctionProtoType>()) {
633      Out << 'F';
634      VisitType(FT->getResultType());
635      for (FunctionProtoType::arg_type_iterator
636            I = FT->arg_type_begin(), E = FT->arg_type_end(); I!=E; ++I) {
637        VisitType(*I);
638      }
639      if (FT->isVariadic())
640        Out << '.';
641      return;
642    }
643    if (const BlockPointerType *BT = T->getAs<BlockPointerType>()) {
644      Out << 'B';
645      T = BT->getPointeeType();
646      continue;
647    }
648    if (const ComplexType *CT = T->getAs<ComplexType>()) {
649      Out << '<';
650      T = CT->getElementType();
651      continue;
652    }
653    if (const TagType *TT = T->getAs<TagType>()) {
654      Out << '$';
655      VisitTagDecl(TT->getDecl());
656      return;
657    }
658    if (const TemplateTypeParmType *TTP = T->getAs<TemplateTypeParmType>()) {
659      Out << 't' << TTP->getDepth() << '.' << TTP->getIndex();
660      return;
661    }
662    if (const TemplateSpecializationType *Spec
663                                    = T->getAs<TemplateSpecializationType>()) {
664      Out << '>';
665      VisitTemplateName(Spec->getTemplateName());
666      Out << Spec->getNumArgs();
667      for (unsigned I = 0, N = Spec->getNumArgs(); I != N; ++I)
668        VisitTemplateArgument(Spec->getArg(I));
669      return;
670    }
671
672    // Unhandled type.
673    Out << ' ';
674    break;
675  } while (true);
676}
677
678void USRGenerator::VisitTemplateParameterList(
679                                         const TemplateParameterList *Params) {
680  if (!Params)
681    return;
682  Out << '>' << Params->size();
683  for (TemplateParameterList::const_iterator P = Params->begin(),
684                                          PEnd = Params->end();
685       P != PEnd; ++P) {
686    Out << '#';
687    if (isa<TemplateTypeParmDecl>(*P)) {
688      if (cast<TemplateTypeParmDecl>(*P)->isParameterPack())
689        Out<< 'p';
690      Out << 'T';
691      continue;
692    }
693
694    if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(*P)) {
695      if (NTTP->isParameterPack())
696        Out << 'p';
697      Out << 'N';
698      VisitType(NTTP->getType());
699      continue;
700    }
701
702    TemplateTemplateParmDecl *TTP = cast<TemplateTemplateParmDecl>(*P);
703    if (TTP->isParameterPack())
704      Out << 'p';
705    Out << 't';
706    VisitTemplateParameterList(TTP->getTemplateParameters());
707  }
708}
709
710void USRGenerator::VisitTemplateName(TemplateName Name) {
711  if (TemplateDecl *Template = Name.getAsTemplateDecl()) {
712    if (TemplateTemplateParmDecl *TTP
713                              = dyn_cast<TemplateTemplateParmDecl>(Template)) {
714      Out << 't' << TTP->getDepth() << '.' << TTP->getIndex();
715      return;
716    }
717
718    Visit(Template);
719    return;
720  }
721
722  // FIXME: Visit dependent template names.
723}
724
725void USRGenerator::VisitTemplateArgument(const TemplateArgument &Arg) {
726  switch (Arg.getKind()) {
727  case TemplateArgument::Null:
728    break;
729
730  case TemplateArgument::Declaration:
731    Visit(Arg.getAsDecl());
732    break;
733
734  case TemplateArgument::NullPtr:
735    break;
736
737  case TemplateArgument::TemplateExpansion:
738    Out << 'P'; // pack expansion of...
739    // Fall through
740  case TemplateArgument::Template:
741    VisitTemplateName(Arg.getAsTemplateOrTemplatePattern());
742    break;
743
744  case TemplateArgument::Expression:
745    // FIXME: Visit expressions.
746    break;
747
748  case TemplateArgument::Pack:
749    Out << 'p' << Arg.pack_size();
750    for (TemplateArgument::pack_iterator P = Arg.pack_begin(), PEnd = Arg.pack_end();
751         P != PEnd; ++P)
752      VisitTemplateArgument(*P);
753    break;
754
755  case TemplateArgument::Type:
756    VisitType(Arg.getAsType());
757    break;
758
759  case TemplateArgument::Integral:
760    Out << 'V';
761    VisitType(Arg.getIntegralType());
762    Out << Arg.getAsIntegral();
763    break;
764  }
765}
766
767//===----------------------------------------------------------------------===//
768// General purpose USR generation methods.
769//===----------------------------------------------------------------------===//
770
771void USRGenerator::GenObjCClass(StringRef cls) {
772  Out << "objc(cs)" << cls;
773}
774
775void USRGenerator::GenObjCCategory(StringRef cls, StringRef cat) {
776  Out << "objc(cy)" << cls << '@' << cat;
777}
778
779void USRGenerator::GenObjCIvar(StringRef ivar) {
780  Out << '@' << ivar;
781}
782
783void USRGenerator::GenObjCMethod(StringRef meth, bool isInstanceMethod) {
784  Out << (isInstanceMethod ? "(im)" : "(cm)") << meth;
785}
786
787void USRGenerator::GenObjCProperty(StringRef prop) {
788  Out << "(py)" << prop;
789}
790
791void USRGenerator::GenObjCProtocol(StringRef prot) {
792  Out << "objc(pl)" << prot;
793}
794
795//===----------------------------------------------------------------------===//
796// API hooks.
797//===----------------------------------------------------------------------===//
798
799static inline StringRef extractUSRSuffix(StringRef s) {
800  return s.startswith("c:") ? s.substr(2) : "";
801}
802
803bool cxcursor::getDeclCursorUSR(const Decl *D, SmallVectorImpl<char> &Buf) {
804  // Don't generate USRs for things with invalid locations.
805  if (!D || D->getLocStart().isInvalid())
806    return true;
807
808  // Check if the cursor has 'NoLinkage'.
809  if (const NamedDecl *ND = dyn_cast<NamedDecl>(D))
810    switch (ND->getLinkage()) {
811      case ExternalLinkage:
812        // Generate USRs for all entities with external linkage.
813        break;
814      case NoLinkage:
815      case UniqueExternalLinkage:
816        // We allow enums, typedefs, and structs that have no linkage to
817        // have USRs that are anchored to the file they were defined in
818        // (e.g., the header).  This is a little gross, but in principal
819        // enums/anonymous structs/etc. defined in a common header file
820        // are referred to across multiple translation units.
821        if (isa<TagDecl>(ND) || isa<TypedefDecl>(ND) ||
822            isa<EnumConstantDecl>(ND) || isa<FieldDecl>(ND) ||
823            isa<VarDecl>(ND) || isa<NamespaceDecl>(ND))
824          break;
825        // Fall-through.
826      case InternalLinkage:
827        if (isa<FunctionDecl>(ND))
828          break;
829    }
830
831  {
832    USRGenerator UG(&D->getASTContext(), &Buf);
833    UG->Visit(const_cast<Decl*>(D));
834
835    if (UG->ignoreResults())
836      return true;
837  }
838
839  return false;
840}
841
842extern "C" {
843
844CXString clang_getCursorUSR(CXCursor C) {
845  const CXCursorKind &K = clang_getCursorKind(C);
846
847  if (clang_isDeclaration(K)) {
848    Decl *D = cxcursor::getCursorDecl(C);
849    if (!D)
850      return createCXString("");
851
852    CXTranslationUnit TU = cxcursor::getCursorTU(C);
853    if (!TU)
854      return createCXString("");
855
856    CXStringBuf *buf = cxstring::getCXStringBuf(TU);
857    if (!buf)
858      return createCXString("");
859
860    bool Ignore = cxcursor::getDeclCursorUSR(D, buf->Data);
861    if (Ignore) {
862      disposeCXStringBuf(buf);
863      return createCXString("");
864    }
865
866    // Return the C-string, but don't make a copy since it is already in
867    // the string buffer.
868    buf->Data.push_back('\0');
869    return createCXString(buf);
870  }
871
872  if (K == CXCursor_MacroDefinition) {
873    CXTranslationUnit TU = cxcursor::getCursorTU(C);
874    if (!TU)
875      return createCXString("");
876
877    CXStringBuf *buf = cxstring::getCXStringBuf(TU);
878    if (!buf)
879      return createCXString("");
880
881    {
882      USRGenerator UG(&cxcursor::getCursorASTUnit(C)->getASTContext(),
883                      &buf->Data);
884      UG << "macro@"
885        << cxcursor::getCursorMacroDefinition(C)->getName()->getNameStart();
886    }
887    buf->Data.push_back('\0');
888    return createCXString(buf);
889  }
890
891  return createCXString("");
892}
893
894CXString clang_constructUSR_ObjCIvar(const char *name, CXString classUSR) {
895  USRGenerator UG;
896  UG << extractUSRSuffix(clang_getCString(classUSR));
897  UG->GenObjCIvar(name);
898  return createCXString(UG.str(), true);
899}
900
901CXString clang_constructUSR_ObjCMethod(const char *name,
902                                       unsigned isInstanceMethod,
903                                       CXString classUSR) {
904  USRGenerator UG;
905  UG << extractUSRSuffix(clang_getCString(classUSR));
906  UG->GenObjCMethod(name, isInstanceMethod);
907  return createCXString(UG.str(), true);
908}
909
910CXString clang_constructUSR_ObjCClass(const char *name) {
911  USRGenerator UG;
912  UG->GenObjCClass(name);
913  return createCXString(UG.str(), true);
914}
915
916CXString clang_constructUSR_ObjCProtocol(const char *name) {
917  USRGenerator UG;
918  UG->GenObjCProtocol(name);
919  return createCXString(UG.str(), true);
920}
921
922CXString clang_constructUSR_ObjCCategory(const char *class_name,
923                                         const char *category_name) {
924  USRGenerator UG;
925  UG->GenObjCCategory(class_name, category_name);
926  return createCXString(UG.str(), true);
927}
928
929CXString clang_constructUSR_ObjCProperty(const char *property,
930                                         CXString classUSR) {
931  USRGenerator UG;
932  UG << extractUSRSuffix(clang_getCString(classUSR));
933  UG->GenObjCProperty(property);
934  return createCXString(UG.str(), true);
935}
936
937} // end extern "C"
938