CIndexUSRs.cpp revision ed122735639d83c10f18c28c7fd117bfcd0f62cb 
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::SmallString<1024> Buf;
34  llvm::raw_svector_ostream Out;
35  bool IgnoreResults;
36  ASTUnit *AU;
37  bool generatedLoc;
38
39  llvm::DenseMap<const Type *, unsigned> TypeSubstitutions;
40
41public:
42  USRGenerator(const CXCursor *C = 0)
43    : Out(Buf),
44      IgnoreResults(false),
45      AU(C ? cxcursor::getCursorASTUnit(*C) : 0),
46      generatedLoc(false)
47  {
48    // Add the USR space prefix.
49    Out << "c:";
50  }
51
52  llvm::StringRef str() {
53    return Out.str();
54  }
55
56  USRGenerator* operator->() { return this; }
57
58  template <typename T>
59  llvm::raw_svector_ostream &operator<<(const T &x) {
60    Out << x;
61    return Out;
62  }
63
64  bool ignoreResults() const { return IgnoreResults; }
65
66  // Visitation methods from generating USRs from AST elements.
67  void VisitDeclContext(DeclContext *D);
68  void VisitFieldDecl(FieldDecl *D);
69  void VisitFunctionDecl(FunctionDecl *D);
70  void VisitNamedDecl(NamedDecl *D);
71  void VisitNamespaceDecl(NamespaceDecl *D);
72  void VisitNamespaceAliasDecl(NamespaceAliasDecl *D);
73  void VisitFunctionTemplateDecl(FunctionTemplateDecl *D);
74  void VisitClassTemplateDecl(ClassTemplateDecl *D);
75  void VisitObjCClassDecl(ObjCClassDecl *CD);
76  void VisitObjCContainerDecl(ObjCContainerDecl *CD);
77  void VisitObjCForwardProtocolDecl(ObjCForwardProtocolDecl *P);
78  void VisitObjCMethodDecl(ObjCMethodDecl *MD);
79  void VisitObjCPropertyDecl(ObjCPropertyDecl *D);
80  void VisitObjCPropertyImplDecl(ObjCPropertyImplDecl *D);
81  void VisitTagDecl(TagDecl *D);
82  void VisitTypedefDecl(TypedefDecl *D);
83  void VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D);
84  void VisitVarDecl(VarDecl *D);
85  void VisitNonTypeTemplateParmDecl(NonTypeTemplateParmDecl *D);
86  void VisitTemplateTemplateParmDecl(TemplateTemplateParmDecl *D);
87  void VisitLinkageSpecDecl(LinkageSpecDecl *D) {
88    IgnoreResults = true;
89  }
90  void VisitUsingDirectiveDecl(UsingDirectiveDecl *D) {
91    IgnoreResults = true;
92  }
93  void VisitUsingDecl(UsingDecl *D) {
94    IgnoreResults = true;
95  }
96  void VisitUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D) {
97    IgnoreResults = true;
98  }
99  void VisitUnresolvedUsingTypenameDecl(UnresolvedUsingTypenameDecl *D) {
100    IgnoreResults = true;
101  }
102
103  /// Generate the string component containing the location of the
104  ///  declaration.
105  bool GenLoc(const Decl *D);
106
107  /// String generation methods used both by the visitation methods
108  /// and from other clients that want to directly generate USRs.  These
109  /// methods do not construct complete USRs (which incorporate the parents
110  /// of an AST element), but only the fragments concerning the AST element
111  /// itself.
112
113  /// Generate a USR for an Objective-C class.
114  void GenObjCClass(llvm::StringRef cls);
115  /// Generate a USR for an Objective-C class category.
116  void GenObjCCategory(llvm::StringRef cls, llvm::StringRef cat);
117  /// Generate a USR fragment for an Objective-C instance variable.  The
118  /// complete USR can be created by concatenating the USR for the
119  /// encompassing class with this USR fragment.
120  void GenObjCIvar(llvm::StringRef ivar);
121  /// Generate a USR fragment for an Objective-C method.
122  void GenObjCMethod(llvm::StringRef sel, bool isInstanceMethod);
123  /// Generate a USR fragment for an Objective-C property.
124  void GenObjCProperty(llvm::StringRef prop);
125  /// Generate a USR for an Objective-C protocol.
126  void GenObjCProtocol(llvm::StringRef prot);
127
128  void VisitType(QualType T);
129  void VisitTemplateParameterList(const TemplateParameterList *Params);
130  void VisitTemplateName(TemplateName Name);
131  void VisitTemplateArgument(const TemplateArgument &Arg);
132
133  /// Emit a Decl's name using NamedDecl::printName() and return true if
134  ///  the decl had no name.
135  bool EmitDeclName(const NamedDecl *D);
136};
137
138} // end anonymous namespace
139
140//===----------------------------------------------------------------------===//
141// Generating USRs from ASTS.
142//===----------------------------------------------------------------------===//
143
144bool USRGenerator::EmitDeclName(const NamedDecl *D) {
145  Out.flush();
146  const unsigned startSize = Buf.size();
147  D->printName(Out);
148  Out.flush();
149  const unsigned endSize = Buf.size();
150  return startSize == endSize;
151}
152
153static bool InAnonymousNamespace(const Decl *D) {
154  if (const NamespaceDecl *ND = dyn_cast<NamespaceDecl>(D->getDeclContext()))
155    return ND->isAnonymousNamespace();
156  return false;
157}
158
159static inline bool ShouldGenerateLocation(const NamedDecl *D) {
160  return D->getLinkage() != ExternalLinkage && !InAnonymousNamespace(D);
161}
162
163void USRGenerator::VisitDeclContext(DeclContext *DC) {
164  if (NamedDecl *D = dyn_cast<NamedDecl>(DC))
165    Visit(D);
166}
167
168void USRGenerator::VisitFieldDecl(FieldDecl *D) {
169  VisitDeclContext(D->getDeclContext());
170  Out << (isa<ObjCIvarDecl>(D) ? "@" : "@FI@");
171  if (EmitDeclName(D)) {
172    // Bit fields can be anonymous.
173    IgnoreResults = true;
174    return;
175  }
176}
177
178void USRGenerator::VisitFunctionDecl(FunctionDecl *D) {
179  if (ShouldGenerateLocation(D) && GenLoc(D))
180    return;
181
182  VisitDeclContext(D->getDeclContext());
183  if (FunctionTemplateDecl *FunTmpl = D->getDescribedFunctionTemplate()) {
184    Out << "@FT@";
185    VisitTemplateParameterList(FunTmpl->getTemplateParameters());
186  } else
187    Out << "@F@";
188  D->printName(Out);
189
190  ASTContext &Ctx = AU->getASTContext();
191  if (!Ctx.getLangOptions().CPlusPlus || D->isExternC())
192    return;
193
194  // Mangle in type information for the arguments.
195  for (FunctionDecl::param_iterator I = D->param_begin(), E = D->param_end();
196       I != E; ++I) {
197    Out << '#';
198    if (ParmVarDecl *PD = *I)
199      VisitType(PD->getType());
200  }
201  if (D->isVariadic())
202    Out << '.';
203  Out << '#';
204  if (CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(D)) {
205    if (MD->isStatic())
206      Out << 'S';
207    if (unsigned quals = MD->getTypeQualifiers())
208      Out << (char)('0' + quals);
209  }
210}
211
212void USRGenerator::VisitNamedDecl(NamedDecl *D) {
213  VisitDeclContext(D->getDeclContext());
214  Out << "@";
215
216  if (EmitDeclName(D)) {
217    // The string can be empty if the declaration has no name; e.g., it is
218    // the ParmDecl with no name for declaration of a function pointer type,
219    // e.g.: void  (*f)(void *);
220    // In this case, don't generate a USR.
221    IgnoreResults = true;
222  }
223}
224
225void USRGenerator::VisitVarDecl(VarDecl *D) {
226  // VarDecls can be declared 'extern' within a function or method body,
227  // but their enclosing DeclContext is the function, not the TU.  We need
228  // to check the storage class to correctly generate the USR.
229  if (ShouldGenerateLocation(D) && GenLoc(D))
230    return;
231
232  VisitDeclContext(D->getDeclContext());
233
234  // Variables always have simple names.
235  llvm::StringRef s = D->getName();
236
237  // The string can be empty if the declaration has no name; e.g., it is
238  // the ParmDecl with no name for declaration of a function pointer type, e.g.:
239  //    void  (*f)(void *);
240  // In this case, don't generate a USR.
241  if (s.empty())
242    IgnoreResults = true;
243  else
244    Out << '@' << s;
245}
246
247void USRGenerator::VisitNonTypeTemplateParmDecl(NonTypeTemplateParmDecl *D) {
248  GenLoc(D);
249  return;
250}
251
252void USRGenerator::VisitTemplateTemplateParmDecl(TemplateTemplateParmDecl *D) {
253  GenLoc(D);
254  return;
255}
256
257void USRGenerator::VisitNamespaceDecl(NamespaceDecl *D) {
258  if (D->isAnonymousNamespace()) {
259    Out << "@aN";
260    return;
261  }
262
263  VisitDeclContext(D->getDeclContext());
264  if (!IgnoreResults)
265    Out << "@N@" << D->getName();
266}
267
268void USRGenerator::VisitFunctionTemplateDecl(FunctionTemplateDecl *D) {
269  VisitFunctionDecl(D->getTemplatedDecl());
270}
271
272void USRGenerator::VisitClassTemplateDecl(ClassTemplateDecl *D) {
273  VisitTagDecl(D->getTemplatedDecl());
274}
275
276void USRGenerator::VisitNamespaceAliasDecl(NamespaceAliasDecl *D) {
277  VisitDeclContext(D->getDeclContext());
278  if (!IgnoreResults)
279    Out << "@NA@" << D->getName();
280}
281
282void USRGenerator::VisitObjCMethodDecl(ObjCMethodDecl *D) {
283  Decl *container = cast<Decl>(D->getDeclContext());
284
285  // The USR for a method declared in a class extension is based on
286  // the ObjCInterfaceDecl, not the ObjCCategoryDecl.
287  do {
288    if (ObjCCategoryDecl *CD = dyn_cast<ObjCCategoryDecl>(container))
289      if (CD->IsClassExtension()) {
290        // ID can be null with invalid code.
291        if (ObjCInterfaceDecl *ID = CD->getClassInterface()) {
292          Visit(ID);
293          break;
294        }
295        // Invalid code.  Can't generate USR.
296        IgnoreResults = true;
297        return;
298      }
299
300    Visit(container);
301  }
302  while (false);
303
304  // Ideally we would use 'GenObjCMethod', but this is such a hot path
305  // for Objective-C code that we don't want to use
306  // DeclarationName::getAsString().
307  Out << (D->isInstanceMethod() ? "(im)" : "(cm)");
308  DeclarationName N(D->getSelector());
309  N.printName(Out);
310}
311
312void USRGenerator::VisitObjCClassDecl(ObjCClassDecl *D) {
313  // FIXME: @class declarations can refer to multiple classes.  We need
314  //  to be able to traverse these.
315  IgnoreResults = true;
316}
317
318void USRGenerator::VisitObjCForwardProtocolDecl(ObjCForwardProtocolDecl *D) {
319  // FIXME: @protocol declarations can refer to multiple protocols.  We need
320  //  to be able to traverse these.
321  IgnoreResults = true;
322}
323
324void USRGenerator::VisitObjCContainerDecl(ObjCContainerDecl *D) {
325  switch (D->getKind()) {
326    default:
327      assert(false && "Invalid ObjC container.");
328    case Decl::ObjCInterface:
329    case Decl::ObjCImplementation:
330      GenObjCClass(D->getName());
331      break;
332    case Decl::ObjCCategory: {
333      ObjCCategoryDecl *CD = cast<ObjCCategoryDecl>(D);
334      ObjCInterfaceDecl *ID = CD->getClassInterface();
335      if (!ID) {
336        // Handle invalid code where the @interface might not
337        // have been specified.
338        // FIXME: We should be able to generate this USR even if the
339        // @interface isn't available.
340        IgnoreResults = true;
341        return;
342      }
343      // Specially handle class extensions, which are anonymous categories.
344      // We want to mangle in the location to uniquely distinguish them.
345      if (CD->IsClassExtension()) {
346        Out << "objc(ext)" << ID->getName() << '@';
347        GenLoc(CD);
348      }
349      else
350        GenObjCCategory(ID->getName(), CD->getName());
351
352      break;
353    }
354    case Decl::ObjCCategoryImpl: {
355      ObjCCategoryImplDecl *CD = cast<ObjCCategoryImplDecl>(D);
356      ObjCInterfaceDecl *ID = CD->getClassInterface();
357      if (!ID) {
358        // Handle invalid code where the @interface might not
359        // have been specified.
360        // FIXME: We should be able to generate this USR even if the
361        // @interface isn't available.
362        IgnoreResults = true;
363        return;
364      }
365      GenObjCCategory(ID->getName(), CD->getName());
366      break;
367    }
368    case Decl::ObjCProtocol:
369      GenObjCProtocol(cast<ObjCProtocolDecl>(D)->getName());
370      break;
371  }
372}
373
374void USRGenerator::VisitObjCPropertyDecl(ObjCPropertyDecl *D) {
375  Visit(cast<Decl>(D->getDeclContext()));
376  GenObjCProperty(D->getName());
377}
378
379void USRGenerator::VisitObjCPropertyImplDecl(ObjCPropertyImplDecl *D) {
380  if (ObjCPropertyDecl *PD = D->getPropertyDecl()) {
381    VisitObjCPropertyDecl(PD);
382    return;
383  }
384
385  IgnoreResults = true;
386}
387
388void USRGenerator::VisitTagDecl(TagDecl *D) {
389  // Add the location of the tag decl to handle resolution across
390  // translation units.
391  if (ShouldGenerateLocation(D) && GenLoc(D))
392    return;
393
394  D = D->getCanonicalDecl();
395  VisitDeclContext(D->getDeclContext());
396
397  bool AlreadyStarted = false;
398  if (CXXRecordDecl *CXXRecord = dyn_cast<CXXRecordDecl>(D)) {
399    if (ClassTemplateDecl *ClassTmpl = CXXRecord->getDescribedClassTemplate()) {
400      AlreadyStarted = true;
401
402      switch (D->getTagKind()) {
403      case TTK_Struct: Out << "@ST"; break;
404      case TTK_Class:  Out << "@CT"; break;
405      case TTK_Union:  Out << "@UT"; break;
406      case TTK_Enum: llvm_unreachable("enum template"); break;
407      }
408      VisitTemplateParameterList(ClassTmpl->getTemplateParameters());
409    } else if (ClassTemplatePartialSpecializationDecl *PartialSpec
410                = dyn_cast<ClassTemplatePartialSpecializationDecl>(CXXRecord)) {
411      AlreadyStarted = true;
412
413      switch (D->getTagKind()) {
414      case TTK_Struct: Out << "@SP"; break;
415      case TTK_Class:  Out << "@CP"; break;
416      case TTK_Union:  Out << "@UP"; break;
417      case TTK_Enum: llvm_unreachable("enum partial specialization"); break;
418      }
419      VisitTemplateParameterList(PartialSpec->getTemplateParameters());
420    }
421  }
422
423  if (!AlreadyStarted) {
424    switch (D->getTagKind()) {
425      case TTK_Struct: Out << "@S"; break;
426      case TTK_Class:  Out << "@C"; break;
427      case TTK_Union:  Out << "@U"; break;
428      case TTK_Enum:   Out << "@E"; break;
429    }
430  }
431
432  Out << '@';
433  Out.flush();
434  assert(Buf.size() > 0);
435  const unsigned off = Buf.size() - 1;
436
437  if (EmitDeclName(D)) {
438    if (const TypedefDecl *TD = D->getTypedefForAnonDecl()) {
439      Buf[off] = 'A';
440      Out << '@' << TD;
441    }
442    else
443      Buf[off] = 'a';
444  }
445
446  // For a class template specialization, mangle the template arguments.
447  if (ClassTemplateSpecializationDecl *Spec
448                              = dyn_cast<ClassTemplateSpecializationDecl>(D)) {
449    const TemplateArgumentList &Args = Spec->getTemplateInstantiationArgs();
450    Out << '>';
451    for (unsigned I = 0, N = Args.size(); I != N; ++I) {
452      Out << '#';
453      VisitTemplateArgument(Args.get(I));
454    }
455  }
456}
457
458void USRGenerator::VisitTypedefDecl(TypedefDecl *D) {
459  if (ShouldGenerateLocation(D) && GenLoc(D))
460    return;
461  DeclContext *DC = D->getDeclContext();
462  if (NamedDecl *DCN = dyn_cast<NamedDecl>(DC))
463    Visit(DCN);
464  Out << "@T@";
465  Out << D->getName();
466}
467
468void USRGenerator::VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D) {
469  GenLoc(D);
470  return;
471}
472
473bool USRGenerator::GenLoc(const Decl *D) {
474  if (generatedLoc)
475    return IgnoreResults;
476  generatedLoc = true;
477
478  const SourceManager &SM = AU->getSourceManager();
479  SourceLocation L = D->getLocStart();
480  if (L.isInvalid()) {
481    IgnoreResults = true;
482    return true;
483  }
484  L = SM.getInstantiationLoc(L);
485  const std::pair<FileID, unsigned> &Decomposed = SM.getDecomposedLoc(L);
486  const FileEntry *FE = SM.getFileEntryForID(Decomposed.first);
487  if (FE) {
488    llvm::sys::Path P(FE->getName());
489    Out << P.getLast();
490  }
491  else {
492    // This case really isn't interesting.
493    IgnoreResults = true;
494    return true;
495  }
496  // Use the offest into the FileID to represent the location.  Using
497  // a line/column can cause us to look back at the original source file,
498  // which is expensive.
499  Out << '@' << Decomposed.second;
500  return IgnoreResults;
501}
502
503void USRGenerator::VisitType(QualType T) {
504  // This method mangles in USR information for types.  It can possibly
505  // just reuse the naming-mangling logic used by codegen, although the
506  // requirements for USRs might not be the same.
507  ASTContext &Ctx = AU->getASTContext();
508
509  do {
510    T = Ctx.getCanonicalType(T);
511    Qualifiers Q = T.getQualifiers();
512    unsigned qVal = 0;
513    if (Q.hasConst())
514      qVal |= 0x1;
515    if (Q.hasVolatile())
516      qVal |= 0x2;
517    if (Q.hasRestrict())
518      qVal |= 0x4;
519    if(qVal)
520      Out << ((char) ('0' + qVal));
521
522    // Mangle in ObjC GC qualifiers?
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:
552          c = 'W'; break;
553        case BuiltinType::Short:
554          c = 'S'; break;
555        case BuiltinType::Int:
556          c = 'I'; break;
557        case BuiltinType::Long:
558          c = 'L'; break;
559        case BuiltinType::LongLong:
560          c = 'K'; break;
561        case BuiltinType::Int128:
562          c = 'J'; break;
563        case BuiltinType::Float:
564          c = 'f'; break;
565        case BuiltinType::Double:
566          c = 'd'; break;
567        case BuiltinType::LongDouble:
568          c = 'D'; break;
569        case BuiltinType::NullPtr:
570          c = 'n'; break;
571        case BuiltinType::Overload:
572        case BuiltinType::Dependent:
573        case BuiltinType::UndeducedAuto:
574          IgnoreResults = true;
575          return;
576        case BuiltinType::ObjCId:
577          c = 'o'; break;
578        case BuiltinType::ObjCClass:
579          c = 'O'; break;
580        case BuiltinType::ObjCSel:
581          c = 'e'; break;
582      }
583      Out << c;
584      return;
585    }
586
587    // If we have already seen this (non-built-in) type, use a substitution
588    // encoding.
589    llvm::DenseMap<const Type *, unsigned>::iterator Substitution
590      = TypeSubstitutions.find(T.getTypePtr());
591    if (Substitution != TypeSubstitutions.end()) {
592      Out << 'S' << Substitution->second << '_';
593      return;
594    } else {
595      // Record this as a substitution.
596      unsigned Number = TypeSubstitutions.size();
597      TypeSubstitutions[T.getTypePtr()] = Number;
598    }
599
600    if (const PointerType *PT = T->getAs<PointerType>()) {
601      Out << '*';
602      T = PT->getPointeeType();
603      continue;
604    }
605    if (const ReferenceType *RT = T->getAs<ReferenceType>()) {
606      Out << '&';
607      T = RT->getPointeeType();
608      continue;
609    }
610    if (const FunctionProtoType *FT = T->getAs<FunctionProtoType>()) {
611      Out << 'F';
612      VisitType(FT->getResultType());
613      for (FunctionProtoType::arg_type_iterator
614            I = FT->arg_type_begin(), E = FT->arg_type_end(); I!=E; ++I) {
615        VisitType(*I);
616      }
617      if (FT->isVariadic())
618        Out << '.';
619      return;
620    }
621    if (const BlockPointerType *BT = T->getAs<BlockPointerType>()) {
622      Out << 'B';
623      T = BT->getPointeeType();
624      continue;
625    }
626    if (const ComplexType *CT = T->getAs<ComplexType>()) {
627      Out << '<';
628      T = CT->getElementType();
629      continue;
630    }
631    if (const TagType *TT = T->getAs<TagType>()) {
632      Out << '$';
633      VisitTagDecl(TT->getDecl());
634      return;
635    }
636    if (const TemplateTypeParmType *TTP = T->getAs<TemplateTypeParmType>()) {
637      Out << 't' << TTP->getDepth() << '.' << TTP->getIndex();
638      return;
639    }
640    if (const TemplateSpecializationType *Spec
641                                    = T->getAs<TemplateSpecializationType>()) {
642      Out << '>';
643      VisitTemplateName(Spec->getTemplateName());
644      Out << Spec->getNumArgs();
645      for (unsigned I = 0, N = Spec->getNumArgs(); I != N; ++I)
646        VisitTemplateArgument(Spec->getArg(I));
647      return;
648    }
649
650    // Unhandled type.
651    Out << ' ';
652    break;
653  } while (true);
654}
655
656void USRGenerator::VisitTemplateParameterList(
657                                         const TemplateParameterList *Params) {
658  if (!Params)
659    return;
660  Out << '>' << Params->size();
661  for (TemplateParameterList::const_iterator P = Params->begin(),
662                                          PEnd = Params->end();
663       P != PEnd; ++P) {
664    Out << '#';
665    if (isa<TemplateTypeParmDecl>(*P)) {
666      Out << 'T';
667      continue;
668    }
669
670    if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(*P)) {
671      Out << 'N';
672      VisitType(NTTP->getType());
673      continue;
674    }
675
676    TemplateTemplateParmDecl *TTP = cast<TemplateTemplateParmDecl>(*P);
677    Out << 't';
678    VisitTemplateParameterList(TTP->getTemplateParameters());
679  }
680}
681
682void USRGenerator::VisitTemplateName(TemplateName Name) {
683  if (TemplateDecl *Template = Name.getAsTemplateDecl()) {
684    if (TemplateTemplateParmDecl *TTP
685                              = dyn_cast<TemplateTemplateParmDecl>(Template)) {
686      Out << 't' << TTP->getDepth() << '.' << TTP->getIndex();
687      return;
688    }
689
690    Visit(Template);
691    return;
692  }
693
694  // FIXME: Visit dependent template names.
695}
696
697void USRGenerator::VisitTemplateArgument(const TemplateArgument &Arg) {
698  switch (Arg.getKind()) {
699  case TemplateArgument::Null:
700    break;
701
702  case TemplateArgument::Declaration:
703    if (Decl *D = Arg.getAsDecl())
704      Visit(D);
705    break;
706
707  case TemplateArgument::Template:
708    VisitTemplateName(Arg.getAsTemplate());
709    break;
710
711  case TemplateArgument::Expression:
712    // FIXME: Visit expressions.
713    break;
714
715  case TemplateArgument::Pack:
716    // FIXME: Variadic templates
717    break;
718
719  case TemplateArgument::Type:
720    VisitType(Arg.getAsType());
721    break;
722
723  case TemplateArgument::Integral:
724    Out << 'V';
725    VisitType(Arg.getIntegralType());
726    Out << *Arg.getAsIntegral();
727    break;
728  }
729}
730
731//===----------------------------------------------------------------------===//
732// General purpose USR generation methods.
733//===----------------------------------------------------------------------===//
734
735void USRGenerator::GenObjCClass(llvm::StringRef cls) {
736  Out << "objc(cs)" << cls;
737}
738
739void USRGenerator::GenObjCCategory(llvm::StringRef cls, llvm::StringRef cat) {
740  Out << "objc(cy)" << cls << '@' << cat;
741}
742
743void USRGenerator::GenObjCIvar(llvm::StringRef ivar) {
744  Out << '@' << ivar;
745}
746
747void USRGenerator::GenObjCMethod(llvm::StringRef meth, bool isInstanceMethod) {
748  Out << (isInstanceMethod ? "(im)" : "(cm)") << meth;
749}
750
751void USRGenerator::GenObjCProperty(llvm::StringRef prop) {
752  Out << "(py)" << prop;
753}
754
755void USRGenerator::GenObjCProtocol(llvm::StringRef prot) {
756  Out << "objc(pl)" << prot;
757}
758
759//===----------------------------------------------------------------------===//
760// API hooks.
761//===----------------------------------------------------------------------===//
762
763static inline llvm::StringRef extractUSRSuffix(llvm::StringRef s) {
764  return s.startswith("c:") ? s.substr(2) : "";
765}
766
767static CXString getDeclCursorUSR(const CXCursor &C) {
768  Decl *D = cxcursor::getCursorDecl(C);
769
770  // Don't generate USRs for things with invalid locations.
771  if (!D || D->getLocStart().isInvalid())
772    return createCXString("");
773
774  // Check if the cursor has 'NoLinkage'.
775  if (const NamedDecl *ND = dyn_cast<NamedDecl>(D))
776    switch (ND->getLinkage()) {
777      case ExternalLinkage:
778        // Generate USRs for all entities with external linkage.
779        break;
780      case NoLinkage:
781      case UniqueExternalLinkage:
782        // We allow enums, typedefs, and structs that have no linkage to
783        // have USRs that are anchored to the file they were defined in
784        // (e.g., the header).  This is a little gross, but in principal
785        // enums/anonymous structs/etc. defined in a common header file
786        // are referred to across multiple translation units.
787        if (isa<TagDecl>(ND) || isa<TypedefDecl>(ND) ||
788            isa<EnumConstantDecl>(ND) || isa<FieldDecl>(ND) ||
789            isa<VarDecl>(ND) || isa<NamespaceDecl>(ND))
790          break;
791        // Fall-through.
792      case InternalLinkage:
793        if (isa<FunctionDecl>(ND))
794          break;
795    }
796
797  USRGenerator UG(&C);
798  UG->Visit(D);
799
800  if (UG->ignoreResults())
801    return createCXString("");
802
803#if 0
804  // For development testing.
805  assert(UG.str().size() > 2);
806#endif
807
808    // Return a copy of the string that must be disposed by the caller.
809  return createCXString(UG.str(), true);
810}
811
812extern "C" {
813
814CXString clang_getCursorUSR(CXCursor C) {
815  const CXCursorKind &K = clang_getCursorKind(C);
816
817  if (clang_isDeclaration(K))
818      return getDeclCursorUSR(C);
819
820  if (K == CXCursor_MacroDefinition) {
821    USRGenerator UG(&C);
822    UG << "macro@"
823       << cxcursor::getCursorMacroDefinition(C)->getName()->getNameStart();
824    return createCXString(UG.str(), true);
825  }
826
827  return createCXString("");
828}
829
830CXString clang_constructUSR_ObjCIvar(const char *name, CXString classUSR) {
831  USRGenerator UG;
832  UG << extractUSRSuffix(clang_getCString(classUSR));
833  UG->GenObjCIvar(name);
834  return createCXString(UG.str(), true);
835}
836
837CXString clang_constructUSR_ObjCMethod(const char *name,
838                                       unsigned isInstanceMethod,
839                                       CXString classUSR) {
840  USRGenerator UG;
841  UG << extractUSRSuffix(clang_getCString(classUSR));
842  UG->GenObjCMethod(name, isInstanceMethod);
843  return createCXString(UG.str(), true);
844}
845
846CXString clang_constructUSR_ObjCClass(const char *name) {
847  USRGenerator UG;
848  UG->GenObjCClass(name);
849  return createCXString(UG.str(), true);
850}
851
852CXString clang_constructUSR_ObjCProtocol(const char *name) {
853  USRGenerator UG;
854  UG->GenObjCProtocol(name);
855  return createCXString(UG.str(), true);
856}
857
858CXString clang_constructUSR_ObjCCategory(const char *class_name,
859                                         const char *category_name) {
860  USRGenerator UG;
861  UG->GenObjCCategory(class_name, category_name);
862  return createCXString(UG.str(), true);
863}
864
865CXString clang_constructUSR_ObjCProperty(const char *property,
866                                         CXString classUSR) {
867  USRGenerator UG;
868  UG << extractUSRSuffix(clang_getCString(classUSR));
869  UG->GenObjCProperty(property);
870  return createCXString(UG.str(), true);
871}
872
873} // end extern "C"
874