CIndexUSRs.cpp revision 8d0eb2f71fb74bd7f5a145e811910273abc98a39 
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 ConstDeclVisitor<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(const DeclContext *D);
71  void VisitFieldDecl(const FieldDecl *D);
72  void VisitFunctionDecl(const FunctionDecl *D);
73  void VisitNamedDecl(const NamedDecl *D);
74  void VisitNamespaceDecl(const NamespaceDecl *D);
75  void VisitNamespaceAliasDecl(const NamespaceAliasDecl *D);
76  void VisitFunctionTemplateDecl(const FunctionTemplateDecl *D);
77  void VisitClassTemplateDecl(const ClassTemplateDecl *D);
78  void VisitObjCContainerDecl(const ObjCContainerDecl *CD);
79  void VisitObjCMethodDecl(const ObjCMethodDecl *MD);
80  void VisitObjCPropertyDecl(const ObjCPropertyDecl *D);
81  void VisitObjCPropertyImplDecl(const ObjCPropertyImplDecl *D);
82  void VisitTagDecl(const TagDecl *D);
83  void VisitTypedefDecl(const TypedefDecl *D);
84  void VisitTemplateTypeParmDecl(const TemplateTypeParmDecl *D);
85  void VisitVarDecl(const VarDecl *D);
86  void VisitNonTypeTemplateParmDecl(const NonTypeTemplateParmDecl *D);
87  void VisitTemplateTemplateParmDecl(const TemplateTemplateParmDecl *D);
88  void VisitLinkageSpecDecl(const LinkageSpecDecl *D) {
89    IgnoreResults = true;
90  }
91  void VisitUsingDirectiveDecl(const UsingDirectiveDecl *D) {
92    IgnoreResults = true;
93  }
94  void VisitUsingDecl(const UsingDecl *D) {
95    IgnoreResults = true;
96  }
97  void VisitUnresolvedUsingValueDecl(const UnresolvedUsingValueDecl *D) {
98    IgnoreResults = true;
99  }
100  void VisitUnresolvedUsingTypenameDecl(const 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 inline bool ShouldGenerateLocation(const NamedDecl *D) {
155  return D->getLinkage() != ExternalLinkage;
156}
157
158void USRGenerator::VisitDeclContext(const DeclContext *DC) {
159  if (const NamedDecl *D = dyn_cast<NamedDecl>(DC))
160    Visit(D);
161}
162
163void USRGenerator::VisitFieldDecl(const FieldDecl *D) {
164  // The USR for an ivar declared in a class extension is based on the
165  // ObjCInterfaceDecl, not the ObjCCategoryDecl.
166  if (const ObjCInterfaceDecl *ID = Context->getObjContainingInterface(D))
167    Visit(ID);
168  else
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(const 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 = *Context;
191  if (!Ctx.getLangOpts().CPlusPlus || D->isExternC())
192    return;
193
194  if (const TemplateArgumentList *
195        SpecArgs = D->getTemplateSpecializationArgs()) {
196    Out << '<';
197    for (unsigned I = 0, N = SpecArgs->size(); I != N; ++I) {
198      Out << '#';
199      VisitTemplateArgument(SpecArgs->get(I));
200    }
201    Out << '>';
202  }
203
204  // Mangle in type information for the arguments.
205  for (FunctionDecl::param_const_iterator I = D->param_begin(),
206                                          E = D->param_end();
207       I != E; ++I) {
208    Out << '#';
209    if (ParmVarDecl *PD = *I)
210      VisitType(PD->getType());
211  }
212  if (D->isVariadic())
213    Out << '.';
214  Out << '#';
215  if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(D)) {
216    if (MD->isStatic())
217      Out << 'S';
218    if (unsigned quals = MD->getTypeQualifiers())
219      Out << (char)('0' + quals);
220  }
221}
222
223void USRGenerator::VisitNamedDecl(const NamedDecl *D) {
224  VisitDeclContext(D->getDeclContext());
225  Out << "@";
226
227  if (EmitDeclName(D)) {
228    // The string can be empty if the declaration has no name; e.g., it is
229    // the ParmDecl with no name for declaration of a function pointer type,
230    // e.g.: void  (*f)(void *);
231    // In this case, don't generate a USR.
232    IgnoreResults = true;
233  }
234}
235
236void USRGenerator::VisitVarDecl(const VarDecl *D) {
237  // VarDecls can be declared 'extern' within a function or method body,
238  // but their enclosing DeclContext is the function, not the TU.  We need
239  // to check the storage class to correctly generate the USR.
240  if (ShouldGenerateLocation(D) && GenLoc(D))
241    return;
242
243  VisitDeclContext(D->getDeclContext());
244
245  // Variables always have simple names.
246  StringRef s = D->getName();
247
248  // The string can be empty if the declaration has no name; e.g., it is
249  // the ParmDecl with no name for declaration of a function pointer type, e.g.:
250  //    void  (*f)(void *);
251  // In this case, don't generate a USR.
252  if (s.empty())
253    IgnoreResults = true;
254  else
255    Out << '@' << s;
256}
257
258void USRGenerator::VisitNonTypeTemplateParmDecl(
259                                        const NonTypeTemplateParmDecl *D) {
260  GenLoc(D);
261  return;
262}
263
264void USRGenerator::VisitTemplateTemplateParmDecl(
265                                        const TemplateTemplateParmDecl *D) {
266  GenLoc(D);
267  return;
268}
269
270void USRGenerator::VisitNamespaceDecl(const NamespaceDecl *D) {
271  if (D->isAnonymousNamespace()) {
272    Out << "@aN";
273    return;
274  }
275
276  VisitDeclContext(D->getDeclContext());
277  if (!IgnoreResults)
278    Out << "@N@" << D->getName();
279}
280
281void USRGenerator::VisitFunctionTemplateDecl(const FunctionTemplateDecl *D) {
282  VisitFunctionDecl(D->getTemplatedDecl());
283}
284
285void USRGenerator::VisitClassTemplateDecl(const ClassTemplateDecl *D) {
286  VisitTagDecl(D->getTemplatedDecl());
287}
288
289void USRGenerator::VisitNamespaceAliasDecl(const NamespaceAliasDecl *D) {
290  VisitDeclContext(D->getDeclContext());
291  if (!IgnoreResults)
292    Out << "@NA@" << D->getName();
293}
294
295void USRGenerator::VisitObjCMethodDecl(const ObjCMethodDecl *D) {
296  const DeclContext *container = D->getDeclContext();
297  if (const ObjCProtocolDecl *pd = dyn_cast<ObjCProtocolDecl>(container)) {
298    Visit(pd);
299  }
300  else {
301    // The USR for a method declared in a class extension or category is based on
302    // the ObjCInterfaceDecl, not the ObjCCategoryDecl.
303    const ObjCInterfaceDecl *ID = D->getClassInterface();
304    if (!ID) {
305      IgnoreResults = true;
306      return;
307    }
308    Visit(ID);
309  }
310  // Ideally we would use 'GenObjCMethod', but this is such a hot path
311  // for Objective-C code that we don't want to use
312  // DeclarationName::getAsString().
313  Out << (D->isInstanceMethod() ? "(im)" : "(cm)");
314  DeclarationName N(D->getSelector());
315  N.printName(Out);
316}
317
318void USRGenerator::VisitObjCContainerDecl(const ObjCContainerDecl *D) {
319  switch (D->getKind()) {
320    default:
321      llvm_unreachable("Invalid ObjC container.");
322    case Decl::ObjCInterface:
323    case Decl::ObjCImplementation:
324      GenObjCClass(D->getName());
325      break;
326    case Decl::ObjCCategory: {
327      const ObjCCategoryDecl *CD = cast<ObjCCategoryDecl>(D);
328      const ObjCInterfaceDecl *ID = CD->getClassInterface();
329      if (!ID) {
330        // Handle invalid code where the @interface might not
331        // have been specified.
332        // FIXME: We should be able to generate this USR even if the
333        // @interface isn't available.
334        IgnoreResults = true;
335        return;
336      }
337      // Specially handle class extensions, which are anonymous categories.
338      // We want to mangle in the location to uniquely distinguish them.
339      if (CD->IsClassExtension()) {
340        Out << "objc(ext)" << ID->getName() << '@';
341        GenLoc(CD);
342      }
343      else
344        GenObjCCategory(ID->getName(), CD->getName());
345
346      break;
347    }
348    case Decl::ObjCCategoryImpl: {
349      const ObjCCategoryImplDecl *CD = cast<ObjCCategoryImplDecl>(D);
350      const ObjCInterfaceDecl *ID = CD->getClassInterface();
351      if (!ID) {
352        // Handle invalid code where the @interface might not
353        // have been specified.
354        // FIXME: We should be able to generate this USR even if the
355        // @interface isn't available.
356        IgnoreResults = true;
357        return;
358      }
359      GenObjCCategory(ID->getName(), CD->getName());
360      break;
361    }
362    case Decl::ObjCProtocol:
363      GenObjCProtocol(cast<ObjCProtocolDecl>(D)->getName());
364      break;
365  }
366}
367
368void USRGenerator::VisitObjCPropertyDecl(const ObjCPropertyDecl *D) {
369  // The USR for a property declared in a class extension or category is based
370  // on the ObjCInterfaceDecl, not the ObjCCategoryDecl.
371  if (const ObjCInterfaceDecl *ID = Context->getObjContainingInterface(D))
372    Visit(ID);
373  else
374    Visit(cast<Decl>(D->getDeclContext()));
375  GenObjCProperty(D->getName());
376}
377
378void USRGenerator::VisitObjCPropertyImplDecl(const ObjCPropertyImplDecl *D) {
379  if (ObjCPropertyDecl *PD = D->getPropertyDecl()) {
380    VisitObjCPropertyDecl(PD);
381    return;
382  }
383
384  IgnoreResults = true;
385}
386
387void USRGenerator::VisitTagDecl(const TagDecl *D) {
388  // Add the location of the tag decl to handle resolution across
389  // translation units.
390  if (ShouldGenerateLocation(D) && GenLoc(D))
391    return;
392
393  D = D->getCanonicalDecl();
394  VisitDeclContext(D->getDeclContext());
395
396  bool AlreadyStarted = false;
397  if (const CXXRecordDecl *CXXRecord = dyn_cast<CXXRecordDecl>(D)) {
398    if (ClassTemplateDecl *ClassTmpl = CXXRecord->getDescribedClassTemplate()) {
399      AlreadyStarted = true;
400
401      switch (D->getTagKind()) {
402      case TTK_Interface:
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");
407      }
408      VisitTemplateParameterList(ClassTmpl->getTemplateParameters());
409    } else if (const ClassTemplatePartialSpecializationDecl *PartialSpec
410                = dyn_cast<ClassTemplatePartialSpecializationDecl>(CXXRecord)) {
411      AlreadyStarted = true;
412
413      switch (D->getTagKind()) {
414      case TTK_Interface:
415      case TTK_Struct: Out << "@SP"; break;
416      case TTK_Class:  Out << "@CP"; break;
417      case TTK_Union:  Out << "@UP"; break;
418      case TTK_Enum: llvm_unreachable("enum partial specialization");
419      }
420      VisitTemplateParameterList(PartialSpec->getTemplateParameters());
421    }
422  }
423
424  if (!AlreadyStarted) {
425    switch (D->getTagKind()) {
426      case TTK_Interface:
427      case TTK_Struct: Out << "@S"; break;
428      case TTK_Class:  Out << "@C"; break;
429      case TTK_Union:  Out << "@U"; break;
430      case TTK_Enum:   Out << "@E"; break;
431    }
432  }
433
434  Out << '@';
435  Out.flush();
436  assert(Buf.size() > 0);
437  const unsigned off = Buf.size() - 1;
438
439  if (EmitDeclName(D)) {
440    if (const TypedefNameDecl *TD = D->getTypedefNameForAnonDecl()) {
441      Buf[off] = 'A';
442      Out << '@' << *TD;
443    }
444    else
445      Buf[off] = 'a';
446  }
447
448  // For a class template specialization, mangle the template arguments.
449  if (const ClassTemplateSpecializationDecl *Spec
450                              = dyn_cast<ClassTemplateSpecializationDecl>(D)) {
451    const TemplateArgumentList &Args = Spec->getTemplateInstantiationArgs();
452    Out << '>';
453    for (unsigned I = 0, N = Args.size(); I != N; ++I) {
454      Out << '#';
455      VisitTemplateArgument(Args.get(I));
456    }
457  }
458}
459
460void USRGenerator::VisitTypedefDecl(const TypedefDecl *D) {
461  if (ShouldGenerateLocation(D) && GenLoc(D))
462    return;
463  const DeclContext *DC = D->getDeclContext();
464  if (const NamedDecl *DCN = dyn_cast<NamedDecl>(DC))
465    Visit(DCN);
466  Out << "@T@";
467  Out << D->getName();
468}
469
470void USRGenerator::VisitTemplateTypeParmDecl(const TemplateTypeParmDecl *D) {
471  GenLoc(D);
472  return;
473}
474
475bool USRGenerator::GenLoc(const Decl *D) {
476  if (generatedLoc)
477    return IgnoreResults;
478  generatedLoc = true;
479
480  // Guard against null declarations in invalid code.
481  if (!D) {
482    IgnoreResults = true;
483    return true;
484  }
485
486  // Use the location of canonical decl.
487  D = D->getCanonicalDecl();
488
489  const SourceManager &SM = Context->getSourceManager();
490  SourceLocation L = D->getLocStart();
491  if (L.isInvalid()) {
492    IgnoreResults = true;
493    return true;
494  }
495  L = SM.getExpansionLoc(L);
496  const std::pair<FileID, unsigned> &Decomposed = SM.getDecomposedLoc(L);
497  const FileEntry *FE = SM.getFileEntryForID(Decomposed.first);
498  if (FE) {
499    Out << llvm::sys::path::filename(FE->getName());
500  }
501  else {
502    // This case really isn't interesting.
503    IgnoreResults = true;
504    return true;
505  }
506  // Use the offest into the FileID to represent the location.  Using
507  // a line/column can cause us to look back at the original source file,
508  // which is expensive.
509  Out << '@' << Decomposed.second;
510  return IgnoreResults;
511}
512
513void USRGenerator::VisitType(QualType T) {
514  // This method mangles in USR information for types.  It can possibly
515  // just reuse the naming-mangling logic used by codegen, although the
516  // requirements for USRs might not be the same.
517  ASTContext &Ctx = *Context;
518
519  do {
520    T = Ctx.getCanonicalType(T);
521    Qualifiers Q = T.getQualifiers();
522    unsigned qVal = 0;
523    if (Q.hasConst())
524      qVal |= 0x1;
525    if (Q.hasVolatile())
526      qVal |= 0x2;
527    if (Q.hasRestrict())
528      qVal |= 0x4;
529    if(qVal)
530      Out << ((char) ('0' + qVal));
531
532    // Mangle in ObjC GC qualifiers?
533
534    if (const PackExpansionType *Expansion = T->getAs<PackExpansionType>()) {
535      Out << 'P';
536      T = Expansion->getPattern();
537    }
538
539    if (const BuiltinType *BT = T->getAs<BuiltinType>()) {
540      unsigned char c = '\0';
541      switch (BT->getKind()) {
542        case BuiltinType::Void:
543          c = 'v'; break;
544        case BuiltinType::Bool:
545          c = 'b'; break;
546        case BuiltinType::Char_U:
547        case BuiltinType::UChar:
548          c = 'c'; break;
549        case BuiltinType::Char16:
550          c = 'q'; break;
551        case BuiltinType::Char32:
552          c = 'w'; break;
553        case BuiltinType::UShort:
554          c = 's'; break;
555        case BuiltinType::UInt:
556          c = 'i'; break;
557        case BuiltinType::ULong:
558          c = 'l'; break;
559        case BuiltinType::ULongLong:
560          c = 'k'; break;
561        case BuiltinType::UInt128:
562          c = 'j'; break;
563        case BuiltinType::Char_S:
564        case BuiltinType::SChar:
565          c = 'C'; break;
566        case BuiltinType::WChar_S:
567        case BuiltinType::WChar_U:
568          c = 'W'; break;
569        case BuiltinType::Short:
570          c = 'S'; break;
571        case BuiltinType::Int:
572          c = 'I'; break;
573        case BuiltinType::Long:
574          c = 'L'; break;
575        case BuiltinType::LongLong:
576          c = 'K'; break;
577        case BuiltinType::Int128:
578          c = 'J'; break;
579        case BuiltinType::Half:
580          c = 'h'; break;
581        case BuiltinType::Float:
582          c = 'f'; break;
583        case BuiltinType::Double:
584          c = 'd'; break;
585        case BuiltinType::LongDouble:
586          c = 'D'; break;
587        case BuiltinType::NullPtr:
588          c = 'n'; break;
589#define BUILTIN_TYPE(Id, SingletonId)
590#define PLACEHOLDER_TYPE(Id, SingletonId) case BuiltinType::Id:
591#include "clang/AST/BuiltinTypes.def"
592        case BuiltinType::Dependent:
593        case BuiltinType::OCLImage1d:
594        case BuiltinType::OCLImage1dArray:
595        case BuiltinType::OCLImage1dBuffer:
596        case BuiltinType::OCLImage2d:
597        case BuiltinType::OCLImage2dArray:
598        case BuiltinType::OCLImage3d:
599        case BuiltinType::OCLEvent:
600          IgnoreResults = true;
601          return;
602        case BuiltinType::ObjCId:
603          c = 'o'; break;
604        case BuiltinType::ObjCClass:
605          c = 'O'; break;
606        case BuiltinType::ObjCSel:
607          c = 'e'; break;
608      }
609      Out << c;
610      return;
611    }
612
613    // If we have already seen this (non-built-in) type, use a substitution
614    // encoding.
615    llvm::DenseMap<const Type *, unsigned>::iterator Substitution
616      = TypeSubstitutions.find(T.getTypePtr());
617    if (Substitution != TypeSubstitutions.end()) {
618      Out << 'S' << Substitution->second << '_';
619      return;
620    } else {
621      // Record this as a substitution.
622      unsigned Number = TypeSubstitutions.size();
623      TypeSubstitutions[T.getTypePtr()] = Number;
624    }
625
626    if (const PointerType *PT = T->getAs<PointerType>()) {
627      Out << '*';
628      T = PT->getPointeeType();
629      continue;
630    }
631    if (const ReferenceType *RT = T->getAs<ReferenceType>()) {
632      Out << '&';
633      T = RT->getPointeeType();
634      continue;
635    }
636    if (const FunctionProtoType *FT = T->getAs<FunctionProtoType>()) {
637      Out << 'F';
638      VisitType(FT->getResultType());
639      for (FunctionProtoType::arg_type_iterator
640            I = FT->arg_type_begin(), E = FT->arg_type_end(); I!=E; ++I) {
641        VisitType(*I);
642      }
643      if (FT->isVariadic())
644        Out << '.';
645      return;
646    }
647    if (const BlockPointerType *BT = T->getAs<BlockPointerType>()) {
648      Out << 'B';
649      T = BT->getPointeeType();
650      continue;
651    }
652    if (const ComplexType *CT = T->getAs<ComplexType>()) {
653      Out << '<';
654      T = CT->getElementType();
655      continue;
656    }
657    if (const TagType *TT = T->getAs<TagType>()) {
658      Out << '$';
659      VisitTagDecl(TT->getDecl());
660      return;
661    }
662    if (const TemplateTypeParmType *TTP = T->getAs<TemplateTypeParmType>()) {
663      Out << 't' << TTP->getDepth() << '.' << TTP->getIndex();
664      return;
665    }
666    if (const TemplateSpecializationType *Spec
667                                    = T->getAs<TemplateSpecializationType>()) {
668      Out << '>';
669      VisitTemplateName(Spec->getTemplateName());
670      Out << Spec->getNumArgs();
671      for (unsigned I = 0, N = Spec->getNumArgs(); I != N; ++I)
672        VisitTemplateArgument(Spec->getArg(I));
673      return;
674    }
675
676    // Unhandled type.
677    Out << ' ';
678    break;
679  } while (true);
680}
681
682void USRGenerator::VisitTemplateParameterList(
683                                         const TemplateParameterList *Params) {
684  if (!Params)
685    return;
686  Out << '>' << Params->size();
687  for (TemplateParameterList::const_iterator P = Params->begin(),
688                                          PEnd = Params->end();
689       P != PEnd; ++P) {
690    Out << '#';
691    if (isa<TemplateTypeParmDecl>(*P)) {
692      if (cast<TemplateTypeParmDecl>(*P)->isParameterPack())
693        Out<< 'p';
694      Out << 'T';
695      continue;
696    }
697
698    if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(*P)) {
699      if (NTTP->isParameterPack())
700        Out << 'p';
701      Out << 'N';
702      VisitType(NTTP->getType());
703      continue;
704    }
705
706    TemplateTemplateParmDecl *TTP = cast<TemplateTemplateParmDecl>(*P);
707    if (TTP->isParameterPack())
708      Out << 'p';
709    Out << 't';
710    VisitTemplateParameterList(TTP->getTemplateParameters());
711  }
712}
713
714void USRGenerator::VisitTemplateName(TemplateName Name) {
715  if (TemplateDecl *Template = Name.getAsTemplateDecl()) {
716    if (TemplateTemplateParmDecl *TTP
717                              = dyn_cast<TemplateTemplateParmDecl>(Template)) {
718      Out << 't' << TTP->getDepth() << '.' << TTP->getIndex();
719      return;
720    }
721
722    Visit(Template);
723    return;
724  }
725
726  // FIXME: Visit dependent template names.
727}
728
729void USRGenerator::VisitTemplateArgument(const TemplateArgument &Arg) {
730  switch (Arg.getKind()) {
731  case TemplateArgument::Null:
732    break;
733
734  case TemplateArgument::Declaration:
735    Visit(Arg.getAsDecl());
736    break;
737
738  case TemplateArgument::NullPtr:
739    break;
740
741  case TemplateArgument::TemplateExpansion:
742    Out << 'P'; // pack expansion of...
743    // Fall through
744  case TemplateArgument::Template:
745    VisitTemplateName(Arg.getAsTemplateOrTemplatePattern());
746    break;
747
748  case TemplateArgument::Expression:
749    // FIXME: Visit expressions.
750    break;
751
752  case TemplateArgument::Pack:
753    Out << 'p' << Arg.pack_size();
754    for (TemplateArgument::pack_iterator P = Arg.pack_begin(), PEnd = Arg.pack_end();
755         P != PEnd; ++P)
756      VisitTemplateArgument(*P);
757    break;
758
759  case TemplateArgument::Type:
760    VisitType(Arg.getAsType());
761    break;
762
763  case TemplateArgument::Integral:
764    Out << 'V';
765    VisitType(Arg.getIntegralType());
766    Out << Arg.getAsIntegral();
767    break;
768  }
769}
770
771//===----------------------------------------------------------------------===//
772// General purpose USR generation methods.
773//===----------------------------------------------------------------------===//
774
775void USRGenerator::GenObjCClass(StringRef cls) {
776  Out << "objc(cs)" << cls;
777}
778
779void USRGenerator::GenObjCCategory(StringRef cls, StringRef cat) {
780  Out << "objc(cy)" << cls << '@' << cat;
781}
782
783void USRGenerator::GenObjCIvar(StringRef ivar) {
784  Out << '@' << ivar;
785}
786
787void USRGenerator::GenObjCMethod(StringRef meth, bool isInstanceMethod) {
788  Out << (isInstanceMethod ? "(im)" : "(cm)") << meth;
789}
790
791void USRGenerator::GenObjCProperty(StringRef prop) {
792  Out << "(py)" << prop;
793}
794
795void USRGenerator::GenObjCProtocol(StringRef prot) {
796  Out << "objc(pl)" << prot;
797}
798
799//===----------------------------------------------------------------------===//
800// API hooks.
801//===----------------------------------------------------------------------===//
802
803static inline StringRef extractUSRSuffix(StringRef s) {
804  return s.startswith("c:") ? s.substr(2) : "";
805}
806
807bool cxcursor::getDeclCursorUSR(const Decl *D, SmallVectorImpl<char> &Buf) {
808  // Don't generate USRs for things with invalid locations.
809  if (!D || D->getLocStart().isInvalid())
810    return true;
811
812  USRGenerator UG(&D->getASTContext(), &Buf);
813  UG->Visit(D);
814
815  if (UG->ignoreResults())
816    return true;
817
818  return false;
819}
820
821extern "C" {
822
823CXString clang_getCursorUSR(CXCursor C) {
824  const CXCursorKind &K = clang_getCursorKind(C);
825
826  if (clang_isDeclaration(K)) {
827    const Decl *D = cxcursor::getCursorDecl(C);
828    if (!D)
829      return cxstring::createEmpty();
830
831    CXTranslationUnit TU = cxcursor::getCursorTU(C);
832    if (!TU)
833      return cxstring::createEmpty();
834
835    CXStringBuf *buf = cxstring::getCXStringBuf(TU);
836    if (!buf)
837      return cxstring::createEmpty();
838
839    bool Ignore = cxcursor::getDeclCursorUSR(D, buf->Data);
840    if (Ignore) {
841      buf->dispose();
842      return cxstring::createEmpty();
843    }
844
845    // Return the C-string, but don't make a copy since it is already in
846    // the string buffer.
847    buf->Data.push_back('\0');
848    return createCXString(buf);
849  }
850
851  if (K == CXCursor_MacroDefinition) {
852    CXTranslationUnit TU = cxcursor::getCursorTU(C);
853    if (!TU)
854      return cxstring::createEmpty();
855
856    CXStringBuf *buf = cxstring::getCXStringBuf(TU);
857    if (!buf)
858      return cxstring::createEmpty();
859
860    {
861      USRGenerator UG(&cxcursor::getCursorASTUnit(C)->getASTContext(),
862                      &buf->Data);
863      UG << "macro@"
864        << cxcursor::getCursorMacroDefinition(C)->getName()->getNameStart();
865    }
866    buf->Data.push_back('\0');
867    return createCXString(buf);
868  }
869
870  return cxstring::createEmpty();
871}
872
873CXString clang_constructUSR_ObjCIvar(const char *name, CXString classUSR) {
874  USRGenerator UG;
875  UG << extractUSRSuffix(clang_getCString(classUSR));
876  UG->GenObjCIvar(name);
877  return cxstring::createDup(UG.str());
878}
879
880CXString clang_constructUSR_ObjCMethod(const char *name,
881                                       unsigned isInstanceMethod,
882                                       CXString classUSR) {
883  USRGenerator UG;
884  UG << extractUSRSuffix(clang_getCString(classUSR));
885  UG->GenObjCMethod(name, isInstanceMethod);
886  return cxstring::createDup(UG.str());
887}
888
889CXString clang_constructUSR_ObjCClass(const char *name) {
890  USRGenerator UG;
891  UG->GenObjCClass(name);
892  return cxstring::createDup(UG.str());
893}
894
895CXString clang_constructUSR_ObjCProtocol(const char *name) {
896  USRGenerator UG;
897  UG->GenObjCProtocol(name);
898  return cxstring::createDup(UG.str());
899}
900
901CXString clang_constructUSR_ObjCCategory(const char *class_name,
902                                         const char *category_name) {
903  USRGenerator UG;
904  UG->GenObjCCategory(class_name, category_name);
905  return cxstring::createDup(UG.str());
906}
907
908CXString clang_constructUSR_ObjCProperty(const char *property,
909                                         CXString classUSR) {
910  USRGenerator UG;
911  UG << extractUSRSuffix(clang_getCString(classUSR));
912  UG->GenObjCProperty(property);
913  return cxstring::createDup(UG.str());
914}
915
916} // end extern "C"
917