CIndexUSRs.cpp revision 472ccff00cdbcd095c3ba933b9e3f202719f118f 
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  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
42public:
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
147bool 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
156static bool InAnonymousNamespace(const Decl *D) {
157  if (const NamespaceDecl *ND = dyn_cast<NamespaceDecl>(D->getDeclContext()))
158    return ND->isAnonymousNamespace();
159  return false;
160}
161
162static inline bool ShouldGenerateLocation(const NamedDecl *D) {
163  return D->getLinkage() != ExternalLinkage && !InAnonymousNamespace(D);
164}
165
166void USRGenerator::VisitDeclContext(DeclContext *DC) {
167  if (NamedDecl *D = dyn_cast<NamedDecl>(DC))
168    Visit(D);
169}
170
171void 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
181void 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
215void 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
228void 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
250void USRGenerator::VisitNonTypeTemplateParmDecl(NonTypeTemplateParmDecl *D) {
251  GenLoc(D);
252  return;
253}
254
255void USRGenerator::VisitTemplateTemplateParmDecl(TemplateTemplateParmDecl *D) {
256  GenLoc(D);
257  return;
258}
259
260void 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
271void USRGenerator::VisitFunctionTemplateDecl(FunctionTemplateDecl *D) {
272  VisitFunctionDecl(D->getTemplatedDecl());
273}
274
275void USRGenerator::VisitClassTemplateDecl(ClassTemplateDecl *D) {
276  VisitTagDecl(D->getTemplatedDecl());
277}
278
279void USRGenerator::VisitNamespaceAliasDecl(NamespaceAliasDecl *D) {
280  VisitDeclContext(D->getDeclContext());
281  if (!IgnoreResults)
282    Out << "@NA@" << D->getName();
283}
284
285void USRGenerator::VisitObjCMethodDecl(ObjCMethodDecl *D) {
286  Decl *container = cast<Decl>(D->getDeclContext());
287
288  // The USR for a method declared in a class extension is based on
289  // the ObjCInterfaceDecl, not the ObjCCategoryDecl.
290  do {
291    if (ObjCCategoryDecl *CD = dyn_cast<ObjCCategoryDecl>(container))
292      if (CD->IsClassExtension()) {
293        // ID can be null with invalid code.
294        if (ObjCInterfaceDecl *ID = CD->getClassInterface()) {
295          Visit(ID);
296          break;
297        }
298        // Invalid code.  Can't generate USR.
299        IgnoreResults = true;
300        return;
301      }
302
303    Visit(container);
304  }
305  while (false);
306
307  // Ideally we would use 'GenObjCMethod', but this is such a hot path
308  // for Objective-C code that we don't want to use
309  // DeclarationName::getAsString().
310  Out << (D->isInstanceMethod() ? "(im)" : "(cm)");
311  DeclarationName N(D->getSelector());
312  N.printName(Out);
313}
314
315void USRGenerator::VisitObjCClassDecl(ObjCClassDecl *D) {
316  // FIXME: @class declarations can refer to multiple classes.  We need
317  //  to be able to traverse these.
318  IgnoreResults = true;
319}
320
321void USRGenerator::VisitObjCForwardProtocolDecl(ObjCForwardProtocolDecl *D) {
322  // FIXME: @protocol declarations can refer to multiple protocols.  We need
323  //  to be able to traverse these.
324  IgnoreResults = true;
325}
326
327void USRGenerator::VisitObjCContainerDecl(ObjCContainerDecl *D) {
328  switch (D->getKind()) {
329    default:
330      assert(false && "Invalid ObjC container.");
331    case Decl::ObjCInterface:
332    case Decl::ObjCImplementation:
333      GenObjCClass(D->getName());
334      break;
335    case Decl::ObjCCategory: {
336      ObjCCategoryDecl *CD = cast<ObjCCategoryDecl>(D);
337      ObjCInterfaceDecl *ID = CD->getClassInterface();
338      if (!ID) {
339        // Handle invalid code where the @interface might not
340        // have been specified.
341        // FIXME: We should be able to generate this USR even if the
342        // @interface isn't available.
343        IgnoreResults = true;
344        return;
345      }
346      // Specially handle class extensions, which are anonymous categories.
347      // We want to mangle in the location to uniquely distinguish them.
348      if (CD->IsClassExtension()) {
349        Out << "objc(ext)" << ID->getName() << '@';
350        GenLoc(CD);
351      }
352      else
353        GenObjCCategory(ID->getName(), CD->getName());
354
355      break;
356    }
357    case Decl::ObjCCategoryImpl: {
358      ObjCCategoryImplDecl *CD = cast<ObjCCategoryImplDecl>(D);
359      ObjCInterfaceDecl *ID = CD->getClassInterface();
360      if (!ID) {
361        // Handle invalid code where the @interface might not
362        // have been specified.
363        // FIXME: We should be able to generate this USR even if the
364        // @interface isn't available.
365        IgnoreResults = true;
366        return;
367      }
368      GenObjCCategory(ID->getName(), CD->getName());
369      break;
370    }
371    case Decl::ObjCProtocol:
372      GenObjCProtocol(cast<ObjCProtocolDecl>(D)->getName());
373      break;
374  }
375}
376
377void USRGenerator::VisitObjCPropertyDecl(ObjCPropertyDecl *D) {
378  Visit(cast<Decl>(D->getDeclContext()));
379  GenObjCProperty(D->getName());
380}
381
382void USRGenerator::VisitObjCPropertyImplDecl(ObjCPropertyImplDecl *D) {
383  if (ObjCPropertyDecl *PD = D->getPropertyDecl()) {
384    VisitObjCPropertyDecl(PD);
385    return;
386  }
387
388  IgnoreResults = true;
389}
390
391void USRGenerator::VisitTagDecl(TagDecl *D) {
392  // Add the location of the tag decl to handle resolution across
393  // translation units.
394  if (ShouldGenerateLocation(D) && GenLoc(D))
395    return;
396
397  D = D->getCanonicalDecl();
398  VisitDeclContext(D->getDeclContext());
399
400  bool AlreadyStarted = false;
401  if (CXXRecordDecl *CXXRecord = dyn_cast<CXXRecordDecl>(D)) {
402    if (ClassTemplateDecl *ClassTmpl = CXXRecord->getDescribedClassTemplate()) {
403      AlreadyStarted = true;
404
405      switch (D->getTagKind()) {
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"); break;
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_Struct: Out << "@SP"; break;
418      case TTK_Class:  Out << "@CP"; break;
419      case TTK_Union:  Out << "@UP"; break;
420      case TTK_Enum: llvm_unreachable("enum partial specialization"); break;
421      }
422      VisitTemplateParameterList(PartialSpec->getTemplateParameters());
423    }
424  }
425
426  if (!AlreadyStarted) {
427    switch (D->getTagKind()) {
428      case TTK_Struct: Out << "@S"; break;
429      case TTK_Class:  Out << "@C"; break;
430      case TTK_Union:  Out << "@U"; break;
431      case TTK_Enum:   Out << "@E"; break;
432    }
433  }
434
435  Out << '@';
436  Out.flush();
437  assert(Buf.size() > 0);
438  const unsigned off = Buf.size() - 1;
439
440  if (EmitDeclName(D)) {
441    if (const TypedefDecl *TD = D->getTypedefForAnonDecl()) {
442      Buf[off] = 'A';
443      Out << '@' << TD;
444    }
445    else
446      Buf[off] = 'a';
447  }
448
449  // For a class template specialization, mangle the template arguments.
450  if (ClassTemplateSpecializationDecl *Spec
451                              = dyn_cast<ClassTemplateSpecializationDecl>(D)) {
452    const TemplateArgumentList &Args = Spec->getTemplateInstantiationArgs();
453    Out << '>';
454    for (unsigned I = 0, N = Args.size(); I != N; ++I) {
455      Out << '#';
456      VisitTemplateArgument(Args.get(I));
457    }
458  }
459}
460
461void USRGenerator::VisitTypedefDecl(TypedefDecl *D) {
462  if (ShouldGenerateLocation(D) && GenLoc(D))
463    return;
464  DeclContext *DC = D->getDeclContext();
465  if (NamedDecl *DCN = dyn_cast<NamedDecl>(DC))
466    Visit(DCN);
467  Out << "@T@";
468  Out << D->getName();
469}
470
471void USRGenerator::VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D) {
472  GenLoc(D);
473  return;
474}
475
476bool USRGenerator::GenLoc(const Decl *D) {
477  if (generatedLoc)
478    return IgnoreResults;
479  generatedLoc = true;
480
481  const SourceManager &SM = AU->getSourceManager();
482  SourceLocation L = D->getLocStart();
483  if (L.isInvalid()) {
484    IgnoreResults = true;
485    return true;
486  }
487  L = SM.getInstantiationLoc(L);
488  const std::pair<FileID, unsigned> &Decomposed = SM.getDecomposedLoc(L);
489  const FileEntry *FE = SM.getFileEntryForID(Decomposed.first);
490  if (FE) {
491    Out << llvm::sys::path::filename(FE->getName());
492  }
493  else {
494    // This case really isn't interesting.
495    IgnoreResults = true;
496    return true;
497  }
498  // Use the offest into the FileID to represent the location.  Using
499  // a line/column can cause us to look back at the original source file,
500  // which is expensive.
501  Out << '@' << Decomposed.second;
502  return IgnoreResults;
503}
504
505void USRGenerator::VisitType(QualType T) {
506  // This method mangles in USR information for types.  It can possibly
507  // just reuse the naming-mangling logic used by codegen, although the
508  // requirements for USRs might not be the same.
509  ASTContext &Ctx = AU->getASTContext();
510
511  do {
512    T = Ctx.getCanonicalType(T);
513    Qualifiers Q = T.getQualifiers();
514    unsigned qVal = 0;
515    if (Q.hasConst())
516      qVal |= 0x1;
517    if (Q.hasVolatile())
518      qVal |= 0x2;
519    if (Q.hasRestrict())
520      qVal |= 0x4;
521    if(qVal)
522      Out << ((char) ('0' + qVal));
523
524    // Mangle in ObjC GC qualifiers?
525
526    if (const BuiltinType *BT = T->getAs<BuiltinType>()) {
527      unsigned char c = '\0';
528      switch (BT->getKind()) {
529        case BuiltinType::Void:
530          c = 'v'; break;
531        case BuiltinType::Bool:
532          c = 'b'; break;
533        case BuiltinType::Char_U:
534        case BuiltinType::UChar:
535          c = 'c'; break;
536        case BuiltinType::Char16:
537          c = 'q'; break;
538        case BuiltinType::Char32:
539          c = 'w'; break;
540        case BuiltinType::UShort:
541          c = 's'; break;
542        case BuiltinType::UInt:
543          c = 'i'; break;
544        case BuiltinType::ULong:
545          c = 'l'; break;
546        case BuiltinType::ULongLong:
547          c = 'k'; break;
548        case BuiltinType::UInt128:
549          c = 'j'; break;
550        case BuiltinType::Char_S:
551        case BuiltinType::SChar:
552          c = 'C'; break;
553        case BuiltinType::WChar:
554          c = 'W'; break;
555        case BuiltinType::Short:
556          c = 'S'; break;
557        case BuiltinType::Int:
558          c = 'I'; break;
559        case BuiltinType::Long:
560          c = 'L'; break;
561        case BuiltinType::LongLong:
562          c = 'K'; break;
563        case BuiltinType::Int128:
564          c = 'J'; break;
565        case BuiltinType::Float:
566          c = 'f'; break;
567        case BuiltinType::Double:
568          c = 'd'; break;
569        case BuiltinType::LongDouble:
570          c = 'D'; break;
571        case BuiltinType::NullPtr:
572          c = 'n'; break;
573        case BuiltinType::Overload:
574        case BuiltinType::Dependent:
575        case BuiltinType::UndeducedAuto:
576          IgnoreResults = true;
577          return;
578        case BuiltinType::ObjCId:
579          c = 'o'; break;
580        case BuiltinType::ObjCClass:
581          c = 'O'; break;
582        case BuiltinType::ObjCSel:
583          c = 'e'; break;
584      }
585      Out << c;
586      return;
587    }
588
589    // If we have already seen this (non-built-in) type, use a substitution
590    // encoding.
591    llvm::DenseMap<const Type *, unsigned>::iterator Substitution
592      = TypeSubstitutions.find(T.getTypePtr());
593    if (Substitution != TypeSubstitutions.end()) {
594      Out << 'S' << Substitution->second << '_';
595      return;
596    } else {
597      // Record this as a substitution.
598      unsigned Number = TypeSubstitutions.size();
599      TypeSubstitutions[T.getTypePtr()] = Number;
600    }
601
602    if (const PointerType *PT = T->getAs<PointerType>()) {
603      Out << '*';
604      T = PT->getPointeeType();
605      continue;
606    }
607    if (const ReferenceType *RT = T->getAs<ReferenceType>()) {
608      Out << '&';
609      T = RT->getPointeeType();
610      continue;
611    }
612    if (const FunctionProtoType *FT = T->getAs<FunctionProtoType>()) {
613      Out << 'F';
614      VisitType(FT->getResultType());
615      for (FunctionProtoType::arg_type_iterator
616            I = FT->arg_type_begin(), E = FT->arg_type_end(); I!=E; ++I) {
617        VisitType(*I);
618      }
619      if (FT->isVariadic())
620        Out << '.';
621      return;
622    }
623    if (const BlockPointerType *BT = T->getAs<BlockPointerType>()) {
624      Out << 'B';
625      T = BT->getPointeeType();
626      continue;
627    }
628    if (const ComplexType *CT = T->getAs<ComplexType>()) {
629      Out << '<';
630      T = CT->getElementType();
631      continue;
632    }
633    if (const TagType *TT = T->getAs<TagType>()) {
634      Out << '$';
635      VisitTagDecl(TT->getDecl());
636      return;
637    }
638    if (const TemplateTypeParmType *TTP = T->getAs<TemplateTypeParmType>()) {
639      Out << 't' << TTP->getDepth() << '.' << TTP->getIndex();
640      return;
641    }
642    if (const TemplateSpecializationType *Spec
643                                    = T->getAs<TemplateSpecializationType>()) {
644      Out << '>';
645      VisitTemplateName(Spec->getTemplateName());
646      Out << Spec->getNumArgs();
647      for (unsigned I = 0, N = Spec->getNumArgs(); I != N; ++I)
648        VisitTemplateArgument(Spec->getArg(I));
649      return;
650    }
651
652    // Unhandled type.
653    Out << ' ';
654    break;
655  } while (true);
656}
657
658void USRGenerator::VisitTemplateParameterList(
659                                         const TemplateParameterList *Params) {
660  if (!Params)
661    return;
662  Out << '>' << Params->size();
663  for (TemplateParameterList::const_iterator P = Params->begin(),
664                                          PEnd = Params->end();
665       P != PEnd; ++P) {
666    Out << '#';
667    if (isa<TemplateTypeParmDecl>(*P)) {
668      Out << 'T';
669      continue;
670    }
671
672    if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(*P)) {
673      Out << 'N';
674      VisitType(NTTP->getType());
675      continue;
676    }
677
678    TemplateTemplateParmDecl *TTP = cast<TemplateTemplateParmDecl>(*P);
679    Out << 't';
680    VisitTemplateParameterList(TTP->getTemplateParameters());
681  }
682}
683
684void USRGenerator::VisitTemplateName(TemplateName Name) {
685  if (TemplateDecl *Template = Name.getAsTemplateDecl()) {
686    if (TemplateTemplateParmDecl *TTP
687                              = dyn_cast<TemplateTemplateParmDecl>(Template)) {
688      Out << 't' << TTP->getDepth() << '.' << TTP->getIndex();
689      return;
690    }
691
692    Visit(Template);
693    return;
694  }
695
696  // FIXME: Visit dependent template names.
697}
698
699void USRGenerator::VisitTemplateArgument(const TemplateArgument &Arg) {
700  switch (Arg.getKind()) {
701  case TemplateArgument::Null:
702    break;
703
704  case TemplateArgument::Declaration:
705    if (Decl *D = Arg.getAsDecl())
706      Visit(D);
707    break;
708
709  case TemplateArgument::Template:
710    VisitTemplateName(Arg.getAsTemplate());
711    break;
712
713  case TemplateArgument::Expression:
714    // FIXME: Visit expressions.
715    break;
716
717  case TemplateArgument::Pack:
718    // FIXME: Variadic templates
719    break;
720
721  case TemplateArgument::Type:
722    VisitType(Arg.getAsType());
723    break;
724
725  case TemplateArgument::Integral:
726    Out << 'V';
727    VisitType(Arg.getIntegralType());
728    Out << *Arg.getAsIntegral();
729    break;
730  }
731}
732
733//===----------------------------------------------------------------------===//
734// General purpose USR generation methods.
735//===----------------------------------------------------------------------===//
736
737void USRGenerator::GenObjCClass(llvm::StringRef cls) {
738  Out << "objc(cs)" << cls;
739}
740
741void USRGenerator::GenObjCCategory(llvm::StringRef cls, llvm::StringRef cat) {
742  Out << "objc(cy)" << cls << '@' << cat;
743}
744
745void USRGenerator::GenObjCIvar(llvm::StringRef ivar) {
746  Out << '@' << ivar;
747}
748
749void USRGenerator::GenObjCMethod(llvm::StringRef meth, bool isInstanceMethod) {
750  Out << (isInstanceMethod ? "(im)" : "(cm)") << meth;
751}
752
753void USRGenerator::GenObjCProperty(llvm::StringRef prop) {
754  Out << "(py)" << prop;
755}
756
757void USRGenerator::GenObjCProtocol(llvm::StringRef prot) {
758  Out << "objc(pl)" << prot;
759}
760
761//===----------------------------------------------------------------------===//
762// API hooks.
763//===----------------------------------------------------------------------===//
764
765static inline llvm::StringRef extractUSRSuffix(llvm::StringRef s) {
766  return s.startswith("c:") ? s.substr(2) : "";
767}
768
769static CXString getDeclCursorUSR(const CXCursor &C) {
770  Decl *D = cxcursor::getCursorDecl(C);
771
772  // Don't generate USRs for things with invalid locations.
773  if (!D || D->getLocStart().isInvalid())
774    return createCXString("");
775
776  // Check if the cursor has 'NoLinkage'.
777  if (const NamedDecl *ND = dyn_cast<NamedDecl>(D))
778    switch (ND->getLinkage()) {
779      case ExternalLinkage:
780        // Generate USRs for all entities with external linkage.
781        break;
782      case NoLinkage:
783      case UniqueExternalLinkage:
784        // We allow enums, typedefs, and structs that have no linkage to
785        // have USRs that are anchored to the file they were defined in
786        // (e.g., the header).  This is a little gross, but in principal
787        // enums/anonymous structs/etc. defined in a common header file
788        // are referred to across multiple translation units.
789        if (isa<TagDecl>(ND) || isa<TypedefDecl>(ND) ||
790            isa<EnumConstantDecl>(ND) || isa<FieldDecl>(ND) ||
791            isa<VarDecl>(ND) || isa<NamespaceDecl>(ND))
792          break;
793        // Fall-through.
794      case InternalLinkage:
795        if (isa<FunctionDecl>(ND))
796          break;
797    }
798
799  CXTranslationUnit TU = cxcursor::getCursorTU(C);
800  if (!TU)
801    return createCXString("");
802
803  CXStringBuf *buf = cxstring::getCXStringBuf(TU);
804  if (!buf)
805    return createCXString("");
806
807  {
808    USRGenerator UG(&C, &buf->Data);
809    UG->Visit(D);
810
811    if (UG->ignoreResults()) {
812      disposeCXStringBuf(buf);
813      return createCXString("");
814    }
815  }
816  // Return the C-string, but don't make a copy since it is already in
817  // the string buffer.
818  buf->Data.push_back('\0');
819  return createCXString(buf);
820}
821
822extern "C" {
823
824CXString clang_getCursorUSR(CXCursor C) {
825  const CXCursorKind &K = clang_getCursorKind(C);
826
827  if (clang_isDeclaration(K))
828      return getDeclCursorUSR(C);
829
830  if (K == CXCursor_MacroDefinition) {
831    CXTranslationUnit TU = cxcursor::getCursorTU(C);
832    if (!TU)
833      return createCXString("");
834
835    CXStringBuf *buf = cxstring::getCXStringBuf(TU);
836    if (!buf)
837      return createCXString("");
838
839    {
840      USRGenerator UG(&C, &buf->Data);
841      UG << "macro@"
842        << cxcursor::getCursorMacroDefinition(C)->getName()->getNameStart();
843    }
844    buf->Data.push_back('\0');
845    return createCXString(buf);
846  }
847
848  return createCXString("");
849}
850
851CXString clang_constructUSR_ObjCIvar(const char *name, CXString classUSR) {
852  USRGenerator UG;
853  UG << extractUSRSuffix(clang_getCString(classUSR));
854  UG->GenObjCIvar(name);
855  return createCXString(UG.str(), true);
856}
857
858CXString clang_constructUSR_ObjCMethod(const char *name,
859                                       unsigned isInstanceMethod,
860                                       CXString classUSR) {
861  USRGenerator UG;
862  UG << extractUSRSuffix(clang_getCString(classUSR));
863  UG->GenObjCMethod(name, isInstanceMethod);
864  return createCXString(UG.str(), true);
865}
866
867CXString clang_constructUSR_ObjCClass(const char *name) {
868  USRGenerator UG;
869  UG->GenObjCClass(name);
870  return createCXString(UG.str(), true);
871}
872
873CXString clang_constructUSR_ObjCProtocol(const char *name) {
874  USRGenerator UG;
875  UG->GenObjCProtocol(name);
876  return createCXString(UG.str(), true);
877}
878
879CXString clang_constructUSR_ObjCCategory(const char *class_name,
880                                         const char *category_name) {
881  USRGenerator UG;
882  UG->GenObjCCategory(class_name, category_name);
883  return createCXString(UG.str(), true);
884}
885
886CXString clang_constructUSR_ObjCProperty(const char *property,
887                                         CXString classUSR) {
888  USRGenerator UG;
889  UG << extractUSRSuffix(clang_getCString(classUSR));
890  UG->GenObjCProperty(property);
891  return createCXString(UG.str(), true);
892}
893
894} // end extern "C"
895