CIndexUSRs.cpp revision 864c041e118155c2b1ce0ba36942a3da5a4a055e 
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  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
308void 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
314void 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
320void 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
370void USRGenerator::VisitObjCPropertyDecl(ObjCPropertyDecl *D) {
371  Visit(cast<Decl>(D->getDeclContext()));
372  GenObjCProperty(D->getName());
373}
374
375void USRGenerator::VisitObjCPropertyImplDecl(ObjCPropertyImplDecl *D) {
376  if (ObjCPropertyDecl *PD = D->getPropertyDecl()) {
377    VisitObjCPropertyDecl(PD);
378    return;
379  }
380
381  IgnoreResults = true;
382}
383
384void 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 TypedefNameDecl *TD = D->getTypedefNameForAnonDecl()) {
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
454void 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
464void USRGenerator::VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D) {
465  GenLoc(D);
466  return;
467}
468
469bool 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
498void 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::BoundMember:
574        case BuiltinType::Dependent:
575        case BuiltinType::UnknownAny:
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      if (cast<TemplateTypeParmDecl>(*P)->isParameterPack())
669        Out<< 'p';
670      Out << 'T';
671      continue;
672    }
673
674    if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(*P)) {
675      if (NTTP->isParameterPack())
676        Out << 'p';
677      Out << 'N';
678      VisitType(NTTP->getType());
679      continue;
680    }
681
682    TemplateTemplateParmDecl *TTP = cast<TemplateTemplateParmDecl>(*P);
683    if (TTP->isParameterPack())
684      Out << 'p';
685    Out << 't';
686    VisitTemplateParameterList(TTP->getTemplateParameters());
687  }
688}
689
690void USRGenerator::VisitTemplateName(TemplateName Name) {
691  if (TemplateDecl *Template = Name.getAsTemplateDecl()) {
692    if (TemplateTemplateParmDecl *TTP
693                              = dyn_cast<TemplateTemplateParmDecl>(Template)) {
694      Out << 't' << TTP->getDepth() << '.' << TTP->getIndex();
695      return;
696    }
697
698    Visit(Template);
699    return;
700  }
701
702  // FIXME: Visit dependent template names.
703}
704
705void USRGenerator::VisitTemplateArgument(const TemplateArgument &Arg) {
706  switch (Arg.getKind()) {
707  case TemplateArgument::Null:
708    break;
709
710  case TemplateArgument::Declaration:
711    if (Decl *D = Arg.getAsDecl())
712      Visit(D);
713    break;
714
715  case TemplateArgument::TemplateExpansion:
716    Out << 'P'; // pack expansion of...
717    // Fall through
718  case TemplateArgument::Template:
719    VisitTemplateName(Arg.getAsTemplateOrTemplatePattern());
720    break;
721
722  case TemplateArgument::Expression:
723    // FIXME: Visit expressions.
724    break;
725
726  case TemplateArgument::Pack:
727    Out << 'p' << Arg.pack_size();
728    for (TemplateArgument::pack_iterator P = Arg.pack_begin(), PEnd = Arg.pack_end();
729         P != PEnd; ++P)
730      VisitTemplateArgument(*P);
731    break;
732
733  case TemplateArgument::Type:
734    VisitType(Arg.getAsType());
735    break;
736
737  case TemplateArgument::Integral:
738    Out << 'V';
739    VisitType(Arg.getIntegralType());
740    Out << *Arg.getAsIntegral();
741    break;
742  }
743}
744
745//===----------------------------------------------------------------------===//
746// General purpose USR generation methods.
747//===----------------------------------------------------------------------===//
748
749void USRGenerator::GenObjCClass(llvm::StringRef cls) {
750  Out << "objc(cs)" << cls;
751}
752
753void USRGenerator::GenObjCCategory(llvm::StringRef cls, llvm::StringRef cat) {
754  Out << "objc(cy)" << cls << '@' << cat;
755}
756
757void USRGenerator::GenObjCIvar(llvm::StringRef ivar) {
758  Out << '@' << ivar;
759}
760
761void USRGenerator::GenObjCMethod(llvm::StringRef meth, bool isInstanceMethod) {
762  Out << (isInstanceMethod ? "(im)" : "(cm)") << meth;
763}
764
765void USRGenerator::GenObjCProperty(llvm::StringRef prop) {
766  Out << "(py)" << prop;
767}
768
769void USRGenerator::GenObjCProtocol(llvm::StringRef prot) {
770  Out << "objc(pl)" << prot;
771}
772
773//===----------------------------------------------------------------------===//
774// API hooks.
775//===----------------------------------------------------------------------===//
776
777static inline llvm::StringRef extractUSRSuffix(llvm::StringRef s) {
778  return s.startswith("c:") ? s.substr(2) : "";
779}
780
781static CXString getDeclCursorUSR(const CXCursor &C) {
782  Decl *D = cxcursor::getCursorDecl(C);
783
784  // Don't generate USRs for things with invalid locations.
785  if (!D || D->getLocStart().isInvalid())
786    return createCXString("");
787
788  // Check if the cursor has 'NoLinkage'.
789  if (const NamedDecl *ND = dyn_cast<NamedDecl>(D))
790    switch (ND->getLinkage()) {
791      case ExternalLinkage:
792        // Generate USRs for all entities with external linkage.
793        break;
794      case NoLinkage:
795      case UniqueExternalLinkage:
796        // We allow enums, typedefs, and structs that have no linkage to
797        // have USRs that are anchored to the file they were defined in
798        // (e.g., the header).  This is a little gross, but in principal
799        // enums/anonymous structs/etc. defined in a common header file
800        // are referred to across multiple translation units.
801        if (isa<TagDecl>(ND) || isa<TypedefDecl>(ND) ||
802            isa<EnumConstantDecl>(ND) || isa<FieldDecl>(ND) ||
803            isa<VarDecl>(ND) || isa<NamespaceDecl>(ND))
804          break;
805        // Fall-through.
806      case InternalLinkage:
807        if (isa<FunctionDecl>(ND))
808          break;
809    }
810
811  CXTranslationUnit TU = cxcursor::getCursorTU(C);
812  if (!TU)
813    return createCXString("");
814
815  CXStringBuf *buf = cxstring::getCXStringBuf(TU);
816  if (!buf)
817    return createCXString("");
818
819  {
820    USRGenerator UG(&C, &buf->Data);
821    UG->Visit(D);
822
823    if (UG->ignoreResults()) {
824      disposeCXStringBuf(buf);
825      return createCXString("");
826    }
827  }
828  // Return the C-string, but don't make a copy since it is already in
829  // the string buffer.
830  buf->Data.push_back('\0');
831  return createCXString(buf);
832}
833
834extern "C" {
835
836CXString clang_getCursorUSR(CXCursor C) {
837  const CXCursorKind &K = clang_getCursorKind(C);
838
839  if (clang_isDeclaration(K))
840      return getDeclCursorUSR(C);
841
842  if (K == CXCursor_MacroDefinition) {
843    CXTranslationUnit TU = cxcursor::getCursorTU(C);
844    if (!TU)
845      return createCXString("");
846
847    CXStringBuf *buf = cxstring::getCXStringBuf(TU);
848    if (!buf)
849      return createCXString("");
850
851    {
852      USRGenerator UG(&C, &buf->Data);
853      UG << "macro@"
854        << cxcursor::getCursorMacroDefinition(C)->getName()->getNameStart();
855    }
856    buf->Data.push_back('\0');
857    return createCXString(buf);
858  }
859
860  return createCXString("");
861}
862
863CXString clang_constructUSR_ObjCIvar(const char *name, CXString classUSR) {
864  USRGenerator UG;
865  UG << extractUSRSuffix(clang_getCString(classUSR));
866  UG->GenObjCIvar(name);
867  return createCXString(UG.str(), true);
868}
869
870CXString clang_constructUSR_ObjCMethod(const char *name,
871                                       unsigned isInstanceMethod,
872                                       CXString classUSR) {
873  USRGenerator UG;
874  UG << extractUSRSuffix(clang_getCString(classUSR));
875  UG->GenObjCMethod(name, isInstanceMethod);
876  return createCXString(UG.str(), true);
877}
878
879CXString clang_constructUSR_ObjCClass(const char *name) {
880  USRGenerator UG;
881  UG->GenObjCClass(name);
882  return createCXString(UG.str(), true);
883}
884
885CXString clang_constructUSR_ObjCProtocol(const char *name) {
886  USRGenerator UG;
887  UG->GenObjCProtocol(name);
888  return createCXString(UG.str(), true);
889}
890
891CXString clang_constructUSR_ObjCCategory(const char *class_name,
892                                         const char *category_name) {
893  USRGenerator UG;
894  UG->GenObjCCategory(class_name, category_name);
895  return createCXString(UG.str(), true);
896}
897
898CXString clang_constructUSR_ObjCProperty(const char *property,
899                                         CXString classUSR) {
900  USRGenerator UG;
901  UG << extractUSRSuffix(clang_getCString(classUSR));
902  UG->GenObjCProperty(property);
903  return createCXString(UG.str(), true);
904}
905
906} // end extern "C"
907