Introduce the clangIDE library.

Libclang has a lot of functionality that is inaccessible.
The purpose of clangIDE is to move most of the functionality of libclang to it so we
can expose it and have libclang be more of a thin C wrapper over clangIDE.

Start by moving the USR generation functionality into clangIDE.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@188569 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 33 insertions, 813 deletions

diff --git a/tools/libclang/CIndexUSRs.cpp b/tools/libclang/CIndexUSRs.cpp
index 4e47435996..1e8d029e8c 100644
--- a/tools/libclang/CIndexUSRs.cpp
+++ b/tools/libclang/CIndexUSRs.cpp
@@ -14,9 +14,7 @@
 #include "CIndexer.h"
 #include "CXCursor.h"
 #include "CXString.h"
-#include "clang/AST/DeclTemplate.h"
-#include "clang/AST/DeclVisitor.h"
-#include "clang/Frontend/ASTUnit.h"
+#include "clang/IDE/USRGeneration.h"
 #include "clang/Lex/PreprocessingRecord.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/Support/raw_ostream.h"
@@ -24,778 +22,6 @@
 using namespace clang;
 
 //===----------------------------------------------------------------------===//
-// USR generation.
-//===----------------------------------------------------------------------===//
-
-namespace {
-class USRGenerator : public ConstDeclVisitor<USRGenerator> {
-  OwningPtr<SmallString<128> > OwnedBuf;
-  SmallVectorImpl<char> &Buf;
-  llvm::raw_svector_ostream Out;
-  bool IgnoreResults;
-  ASTContext *Context;
-  bool generatedLoc;
-  
-  llvm::DenseMap<const Type *, unsigned> TypeSubstitutions;
-  
-public:
-  explicit USRGenerator(ASTContext *Ctx = 0, SmallVectorImpl<char> *extBuf = 0)
-  : OwnedBuf(extBuf ? 0 : new SmallString<128>()),
-    Buf(extBuf ? *extBuf : *OwnedBuf.get()),
-    Out(Buf),
-    IgnoreResults(false),
-    Context(Ctx),
-    generatedLoc(false)
-  {
-    // Add the USR space prefix.
-    Out << "c:";
-  }
-
-  StringRef str() {
-    return Out.str();
-  }
-
-  USRGenerator* operator->() { return this; }
-
-  template <typename T>
-  llvm::raw_svector_ostream &operator<<(const T &x) {
-    Out << x;
-    return Out;
-  }
-
-  bool ignoreResults() const { return IgnoreResults; }
-
-  // Visitation methods from generating USRs from AST elements.
-  void VisitDeclContext(const DeclContext *D);
-  void VisitFieldDecl(const FieldDecl *D);
-  void VisitFunctionDecl(const FunctionDecl *D);
-  void VisitNamedDecl(const NamedDecl *D);
-  void VisitNamespaceDecl(const NamespaceDecl *D);
-  void VisitNamespaceAliasDecl(const NamespaceAliasDecl *D);
-  void VisitFunctionTemplateDecl(const FunctionTemplateDecl *D);
-  void VisitClassTemplateDecl(const ClassTemplateDecl *D);
-  void VisitObjCContainerDecl(const ObjCContainerDecl *CD);
-  void VisitObjCMethodDecl(const ObjCMethodDecl *MD);
-  void VisitObjCPropertyDecl(const ObjCPropertyDecl *D);
-  void VisitObjCPropertyImplDecl(const ObjCPropertyImplDecl *D);
-  void VisitTagDecl(const TagDecl *D);
-  void VisitTypedefDecl(const TypedefDecl *D);
-  void VisitTemplateTypeParmDecl(const TemplateTypeParmDecl *D);
-  void VisitVarDecl(const VarDecl *D);
-  void VisitNonTypeTemplateParmDecl(const NonTypeTemplateParmDecl *D);
-  void VisitTemplateTemplateParmDecl(const TemplateTemplateParmDecl *D);
-  void VisitLinkageSpecDecl(const LinkageSpecDecl *D) {
-    IgnoreResults = true;
-  }
-  void VisitUsingDirectiveDecl(const UsingDirectiveDecl *D) {
-    IgnoreResults = true;
-  }
-  void VisitUsingDecl(const UsingDecl *D) {
-    IgnoreResults = true;
-  }
-  void VisitUnresolvedUsingValueDecl(const UnresolvedUsingValueDecl *D) {
-    IgnoreResults = true;
-  }
-  void VisitUnresolvedUsingTypenameDecl(const UnresolvedUsingTypenameDecl *D) {
-    IgnoreResults = true;
-  }
-  
-  /// Generate the string component containing the location of the
-  ///  declaration.
-  bool GenLoc(const Decl *D);
-
-  /// String generation methods used both by the visitation methods
-  /// and from other clients that want to directly generate USRs.  These
-  /// methods do not construct complete USRs (which incorporate the parents
-  /// of an AST element), but only the fragments concerning the AST element
-  /// itself.
-
-  /// Generate a USR for an Objective-C class.
-  void GenObjCClass(StringRef cls);
-  /// Generate a USR for an Objective-C class category.
-  void GenObjCCategory(StringRef cls, StringRef cat);
-  /// Generate a USR fragment for an Objective-C instance variable.  The
-  /// complete USR can be created by concatenating the USR for the
-  /// encompassing class with this USR fragment.
-  void GenObjCIvar(StringRef ivar);
-  /// Generate a USR fragment for an Objective-C method.
-  void GenObjCMethod(StringRef sel, bool isInstanceMethod);
-  /// Generate a USR fragment for an Objective-C property.
-  void GenObjCProperty(StringRef prop);
-  /// Generate a USR for an Objective-C protocol.
-  void GenObjCProtocol(StringRef prot);
-
-  void VisitType(QualType T);
-  void VisitTemplateParameterList(const TemplateParameterList *Params);
-  void VisitTemplateName(TemplateName Name);
-  void VisitTemplateArgument(const TemplateArgument &Arg);
-  
-  /// Emit a Decl's name using NamedDecl::printName() and return true if
-  ///  the decl had no name.
-  bool EmitDeclName(const NamedDecl *D);
-};
-
-} // end anonymous namespace
-
-//===----------------------------------------------------------------------===//
-// Generating USRs from ASTS.
-//===----------------------------------------------------------------------===//
-
-bool USRGenerator::EmitDeclName(const NamedDecl *D) {
-  Out.flush();
-  const unsigned startSize = Buf.size();
-  D->printName(Out);
-  Out.flush();
-  const unsigned endSize = Buf.size();
-  return startSize == endSize;
-}
-
-static inline bool ShouldGenerateLocation(const NamedDecl *D) {
-  return !D->isExternallyVisible();
-}
-
-void USRGenerator::VisitDeclContext(const DeclContext *DC) {
-  if (const NamedDecl *D = dyn_cast<NamedDecl>(DC))
-    Visit(D);
-}
-
-void USRGenerator::VisitFieldDecl(const FieldDecl *D) {
-  // The USR for an ivar declared in a class extension is based on the
-  // ObjCInterfaceDecl, not the ObjCCategoryDecl.
-  if (const ObjCInterfaceDecl *ID = Context->getObjContainingInterface(D))
-    Visit(ID);
-  else
-    VisitDeclContext(D->getDeclContext());
-  Out << (isa<ObjCIvarDecl>(D) ? "@" : "@FI@");
-  if (EmitDeclName(D)) {
-    // Bit fields can be anonymous.
-    IgnoreResults = true;
-    return;
-  }
-}
-
-void USRGenerator::VisitFunctionDecl(const FunctionDecl *D) {
-  if (ShouldGenerateLocation(D) && GenLoc(D))
-    return;
-
-  VisitDeclContext(D->getDeclContext());
-  if (FunctionTemplateDecl *FunTmpl = D->getDescribedFunctionTemplate()) {
-    Out << "@FT@";
-    VisitTemplateParameterList(FunTmpl->getTemplateParameters());
-  } else
-    Out << "@F@";
-  D->printName(Out);
-
-  ASTContext &Ctx = *Context;
-  if (!Ctx.getLangOpts().CPlusPlus || D->isExternC())
-    return;
-
-  if (const TemplateArgumentList *
-        SpecArgs = D->getTemplateSpecializationArgs()) {
-    Out << '<';
-    for (unsigned I = 0, N = SpecArgs->size(); I != N; ++I) {
-      Out << '#';
-      VisitTemplateArgument(SpecArgs->get(I));
-    }
-    Out << '>';
-  }
-
-  // Mangle in type information for the arguments.
-  for (FunctionDecl::param_const_iterator I = D->param_begin(),
-                                          E = D->param_end();
-       I != E; ++I) {
-    Out << '#';
-    if (ParmVarDecl *PD = *I)
-      VisitType(PD->getType());
-  }
-  if (D->isVariadic())
-    Out << '.';
-  Out << '#';
-  if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(D)) {
-    if (MD->isStatic())
-      Out << 'S';
-    if (unsigned quals = MD->getTypeQualifiers())
-      Out << (char)('0' + quals);
-  }
-}
-
-void USRGenerator::VisitNamedDecl(const NamedDecl *D) {
-  VisitDeclContext(D->getDeclContext());
-  Out << "@";
-
-  if (EmitDeclName(D)) {
-    // The string can be empty if the declaration has no name; e.g., it is
-    // the ParmDecl with no name for declaration of a function pointer type,
-    // e.g.: void  (*f)(void *);
-    // In this case, don't generate a USR.
-    IgnoreResults = true;
-  }
-}
-
-void USRGenerator::VisitVarDecl(const VarDecl *D) {
-  // VarDecls can be declared 'extern' within a function or method body,
-  // but their enclosing DeclContext is the function, not the TU.  We need
-  // to check the storage class to correctly generate the USR.
-  if (ShouldGenerateLocation(D) && GenLoc(D))
-    return;
-
-  VisitDeclContext(D->getDeclContext());
-
-  // Variables always have simple names.
-  StringRef s = D->getName();
-
-  // The string can be empty if the declaration has no name; e.g., it is
-  // the ParmDecl with no name for declaration of a function pointer type, e.g.:
-  //    void  (*f)(void *);
-  // In this case, don't generate a USR.
-  if (s.empty())
-    IgnoreResults = true;
-  else
-    Out << '@' << s;
-}
-
-void USRGenerator::VisitNonTypeTemplateParmDecl(
-                                        const NonTypeTemplateParmDecl *D) {
-  GenLoc(D);
-  return;
-}
-
-void USRGenerator::VisitTemplateTemplateParmDecl(
-                                        const TemplateTemplateParmDecl *D) {
-  GenLoc(D);
-  return;
-}
-
-void USRGenerator::VisitNamespaceDecl(const NamespaceDecl *D) {
-  if (D->isAnonymousNamespace()) {
-    Out << "@aN";
-    return;
-  }
-
-  VisitDeclContext(D->getDeclContext());
-  if (!IgnoreResults)
-    Out << "@N@" << D->getName();
-}
-
-void USRGenerator::VisitFunctionTemplateDecl(const FunctionTemplateDecl *D) {
-  VisitFunctionDecl(D->getTemplatedDecl());
-}
-
-void USRGenerator::VisitClassTemplateDecl(const ClassTemplateDecl *D) {
-  VisitTagDecl(D->getTemplatedDecl());
-}
-
-void USRGenerator::VisitNamespaceAliasDecl(const NamespaceAliasDecl *D) {
-  VisitDeclContext(D->getDeclContext());
-  if (!IgnoreResults)
-    Out << "@NA@" << D->getName();  
-}
-
-void USRGenerator::VisitObjCMethodDecl(const ObjCMethodDecl *D) {
-  const DeclContext *container = D->getDeclContext();
-  if (const ObjCProtocolDecl *pd = dyn_cast<ObjCProtocolDecl>(container)) {
-    Visit(pd);
-  }
-  else {
-    // The USR for a method declared in a class extension or category is based on
-    // the ObjCInterfaceDecl, not the ObjCCategoryDecl.
-    const ObjCInterfaceDecl *ID = D->getClassInterface();
-    if (!ID) {
-      IgnoreResults = true;
-      return;
-    }
-    Visit(ID);
-  }
-  // Ideally we would use 'GenObjCMethod', but this is such a hot path
-  // for Objective-C code that we don't want to use
-  // DeclarationName::getAsString().
-  Out << (D->isInstanceMethod() ? "(im)" : "(cm)")
-      << DeclarationName(D->getSelector());
-}
-
-void USRGenerator::VisitObjCContainerDecl(const ObjCContainerDecl *D) {
-  switch (D->getKind()) {
-    default:
-      llvm_unreachable("Invalid ObjC container.");
-    case Decl::ObjCInterface:
-    case Decl::ObjCImplementation:
-      GenObjCClass(D->getName());
-      break;
-    case Decl::ObjCCategory: {
-      const ObjCCategoryDecl *CD = cast<ObjCCategoryDecl>(D);
-      const ObjCInterfaceDecl *ID = CD->getClassInterface();
-      if (!ID) {
-        // Handle invalid code where the @interface might not
-        // have been specified.
-        // FIXME: We should be able to generate this USR even if the
-        // @interface isn't available.
-        IgnoreResults = true;
-        return;
-      }
-      // Specially handle class extensions, which are anonymous categories.
-      // We want to mangle in the location to uniquely distinguish them.
-      if (CD->IsClassExtension()) {
-        Out << "objc(ext)" << ID->getName() << '@';
-        GenLoc(CD);
-      }
-      else
-        GenObjCCategory(ID->getName(), CD->getName());
-
-      break;
-    }
-    case Decl::ObjCCategoryImpl: {
-      const ObjCCategoryImplDecl *CD = cast<ObjCCategoryImplDecl>(D);
-      const ObjCInterfaceDecl *ID = CD->getClassInterface();
-      if (!ID) {
-        // Handle invalid code where the @interface might not
-        // have been specified.
-        // FIXME: We should be able to generate this USR even if the
-        // @interface isn't available.
-        IgnoreResults = true;
-        return;
-      }
-      GenObjCCategory(ID->getName(), CD->getName());
-      break;
-    }
-    case Decl::ObjCProtocol:
-      GenObjCProtocol(cast<ObjCProtocolDecl>(D)->getName());
-      break;
-  }
-}
-
-void USRGenerator::VisitObjCPropertyDecl(const ObjCPropertyDecl *D) {
-  // The USR for a property declared in a class extension or category is based
-  // on the ObjCInterfaceDecl, not the ObjCCategoryDecl.
-  if (const ObjCInterfaceDecl *ID = Context->getObjContainingInterface(D))
-    Visit(ID);
-  else
-    Visit(cast<Decl>(D->getDeclContext()));
-  GenObjCProperty(D->getName());
-}
-
-void USRGenerator::VisitObjCPropertyImplDecl(const ObjCPropertyImplDecl *D) {
-  if (ObjCPropertyDecl *PD = D->getPropertyDecl()) {
-    VisitObjCPropertyDecl(PD);
-    return;
-  }
-
-  IgnoreResults = true;
-}
-
-void USRGenerator::VisitTagDecl(const TagDecl *D) {
-  // Add the location of the tag decl to handle resolution across
-  // translation units.
-  if (ShouldGenerateLocation(D) && GenLoc(D))
-    return;
-
-  D = D->getCanonicalDecl();
-  VisitDeclContext(D->getDeclContext());
-
-  bool AlreadyStarted = false;
-  if (const CXXRecordDecl *CXXRecord = dyn_cast<CXXRecordDecl>(D)) {
-    if (ClassTemplateDecl *ClassTmpl = CXXRecord->getDescribedClassTemplate()) {
-      AlreadyStarted = true;
-      
-      switch (D->getTagKind()) {
-      case TTK_Interface:
-      case TTK_Struct: Out << "@ST"; break;
-      case TTK_Class:  Out << "@CT"; break;
-      case TTK_Union:  Out << "@UT"; break;
-      case TTK_Enum: llvm_unreachable("enum template");
-      }
-      VisitTemplateParameterList(ClassTmpl->getTemplateParameters());
-    } else if (const ClassTemplatePartialSpecializationDecl *PartialSpec
-                = dyn_cast<ClassTemplatePartialSpecializationDecl>(CXXRecord)) {
-      AlreadyStarted = true;
-      
-      switch (D->getTagKind()) {
-      case TTK_Interface:
-      case TTK_Struct: Out << "@SP"; break;
-      case TTK_Class:  Out << "@CP"; break;
-      case TTK_Union:  Out << "@UP"; break;
-      case TTK_Enum: llvm_unreachable("enum partial specialization");
-      }      
-      VisitTemplateParameterList(PartialSpec->getTemplateParameters());
-    }
-  }
-  
-  if (!AlreadyStarted) {
-    switch (D->getTagKind()) {
-      case TTK_Interface:
-      case TTK_Struct: Out << "@S"; break;
-      case TTK_Class:  Out << "@C"; break;
-      case TTK_Union:  Out << "@U"; break;
-      case TTK_Enum:   Out << "@E"; break;
-    }
-  }
-  
-  Out << '@';
-  Out.flush();
-  assert(Buf.size() > 0);
-  const unsigned off = Buf.size() - 1;
-
-  if (EmitDeclName(D)) {
-    if (const TypedefNameDecl *TD = D->getTypedefNameForAnonDecl()) {
-      Buf[off] = 'A';
-      Out << '@' << *TD;
-    }
-    else
-      Buf[off] = 'a';
-  }
-  
-  // For a class template specialization, mangle the template arguments.
-  if (const ClassTemplateSpecializationDecl *Spec
-                              = dyn_cast<ClassTemplateSpecializationDecl>(D)) {
-    const TemplateArgumentList &Args = Spec->getTemplateInstantiationArgs();
-    Out << '>';
-    for (unsigned I = 0, N = Args.size(); I != N; ++I) {
-      Out << '#';
-      VisitTemplateArgument(Args.get(I));
-    }
-  }
-}
-
-void USRGenerator::VisitTypedefDecl(const TypedefDecl *D) {
-  if (ShouldGenerateLocation(D) && GenLoc(D))
-    return;
-  const DeclContext *DC = D->getDeclContext();
-  if (const NamedDecl *DCN = dyn_cast<NamedDecl>(DC))
-    Visit(DCN);
-  Out << "@T@";
-  Out << D->getName();
-}
-
-void USRGenerator::VisitTemplateTypeParmDecl(const TemplateTypeParmDecl *D) {
-  GenLoc(D);
-  return;
-}
-
-bool USRGenerator::GenLoc(const Decl *D) {
-  if (generatedLoc)
-    return IgnoreResults;
-  generatedLoc = true;
-  
-  // Guard against null declarations in invalid code.
-  if (!D) {
-    IgnoreResults = true;
-    return true;
-  }
-
-  // Use the location of canonical decl.
-  D = D->getCanonicalDecl();
-
-  const SourceManager &SM = Context->getSourceManager();
-  SourceLocation L = D->getLocStart();
-  if (L.isInvalid()) {
-    IgnoreResults = true;
-    return true;
-  }
-  L = SM.getExpansionLoc(L);
-  const std::pair<FileID, unsigned> &Decomposed = SM.getDecomposedLoc(L);
-  const FileEntry *FE = SM.getFileEntryForID(Decomposed.first);
-  if (FE) {
-    Out << llvm::sys::path::filename(FE->getName());
-  }
-  else {
-    // This case really isn't interesting.
-    IgnoreResults = true;
-    return true;
-  }
-  // Use the offest into the FileID to represent the location.  Using
-  // a line/column can cause us to look back at the original source file,
-  // which is expensive.
-  Out << '@' << Decomposed.second;
-  return IgnoreResults;
-}
-
-void USRGenerator::VisitType(QualType T) {
-  // This method mangles in USR information for types.  It can possibly
-  // just reuse the naming-mangling logic used by codegen, although the
-  // requirements for USRs might not be the same.
-  ASTContext &Ctx = *Context;
-
-  do {
-    T = Ctx.getCanonicalType(T);
-    Qualifiers Q = T.getQualifiers();
-    unsigned qVal = 0;
-    if (Q.hasConst())
-      qVal |= 0x1;
-    if (Q.hasVolatile())
-      qVal |= 0x2;
-    if (Q.hasRestrict())
-      qVal |= 0x4;
-    if(qVal)
-      Out << ((char) ('0' + qVal));
-
-    // Mangle in ObjC GC qualifiers?
-
-    if (const PackExpansionType *Expansion = T->getAs<PackExpansionType>()) {
-      Out << 'P';
-      T = Expansion->getPattern();
-    }
-    
-    if (const BuiltinType *BT = T->getAs<BuiltinType>()) {
-      unsigned char c = '\0';
-      switch (BT->getKind()) {
-        case BuiltinType::Void:
-          c = 'v'; break;
-        case BuiltinType::Bool:
-          c = 'b'; break;
-        case BuiltinType::Char_U:
-        case BuiltinType::UChar:
-          c = 'c'; break;
-        case BuiltinType::Char16:
-          c = 'q'; break;
-        case BuiltinType::Char32:
-          c = 'w'; break;
-        case BuiltinType::UShort:
-          c = 's'; break;
-        case BuiltinType::UInt:
-          c = 'i'; break;
-        case BuiltinType::ULong:
-          c = 'l'; break;
-        case BuiltinType::ULongLong:
-          c = 'k'; break;
-        case BuiltinType::UInt128:
-          c = 'j'; break;
-        case BuiltinType::Char_S:
-        case BuiltinType::SChar:
-          c = 'C'; break;
-        case BuiltinType::WChar_S:
-        case BuiltinType::WChar_U:
-          c = 'W'; break;
-        case BuiltinType::Short:
-          c = 'S'; break;
-        case BuiltinType::Int:
-          c = 'I'; break;
-        case BuiltinType::Long:
-          c = 'L'; break;
-        case BuiltinType::LongLong:
-          c = 'K'; break;
-        case BuiltinType::Int128:
-          c = 'J'; break;
-        case BuiltinType::Half:
-          c = 'h'; break;
-        case BuiltinType::Float:
-          c = 'f'; break;
-        case BuiltinType::Double:
-          c = 'd'; break;
-        case BuiltinType::LongDouble:
-          c = 'D'; break;
-        case BuiltinType::NullPtr:
-          c = 'n'; break;
-#define BUILTIN_TYPE(Id, SingletonId)
-#define PLACEHOLDER_TYPE(Id, SingletonId) case BuiltinType::Id:
-#include "clang/AST/BuiltinTypes.def"
-        case BuiltinType::Dependent:
-        case BuiltinType::OCLImage1d:
-        case BuiltinType::OCLImage1dArray:
-        case BuiltinType::OCLImage1dBuffer:
-        case BuiltinType::OCLImage2d:
-        case BuiltinType::OCLImage2dArray:
-        case BuiltinType::OCLImage3d:
-        case BuiltinType::OCLEvent:
-        case BuiltinType::OCLSampler:
-          IgnoreResults = true;
-          return;
-        case BuiltinType::ObjCId:
-          c = 'o'; break;
-        case BuiltinType::ObjCClass:
-          c = 'O'; break;
-        case BuiltinType::ObjCSel:
-          c = 'e'; break;
-      }
-      Out << c;
-      return;
-    }
-
-    // If we have already seen this (non-built-in) type, use a substitution
-    // encoding.
-    llvm::DenseMap<const Type *, unsigned>::iterator Substitution
-      = TypeSubstitutions.find(T.getTypePtr());
-    if (Substitution != TypeSubstitutions.end()) {
-      Out << 'S' << Substitution->second << '_';
-      return;
-    } else {
-      // Record this as a substitution.
-      unsigned Number = TypeSubstitutions.size();
-      TypeSubstitutions[T.getTypePtr()] = Number;
-    }
-    
-    if (const PointerType *PT = T->getAs<PointerType>()) {
-      Out << '*';
-      T = PT->getPointeeType();
-      continue;
-    }
-    if (const ReferenceType *RT = T->getAs<ReferenceType>()) {
-      Out << '&';
-      T = RT->getPointeeType();
-      continue;
-    }
-    if (const FunctionProtoType *FT = T->getAs<FunctionProtoType>()) {
-      Out << 'F';
-      VisitType(FT->getResultType());
-      for (FunctionProtoType::arg_type_iterator
-            I = FT->arg_type_begin(), E = FT->arg_type_end(); I!=E; ++I) {
-        VisitType(*I);
-      }
-      if (FT->isVariadic())
-        Out << '.';
-      return;
-    }
-    if (const BlockPointerType *BT = T->getAs<BlockPointerType>()) {
-      Out << 'B';
-      T = BT->getPointeeType();
-      continue;
-    }
-    if (const ComplexType *CT = T->getAs<ComplexType>()) {
-      Out << '<';
-      T = CT->getElementType();
-      continue;
-    }
-    if (const TagType *TT = T->getAs<TagType>()) {
-      Out << '$';
-      VisitTagDecl(TT->getDecl());
-      return;
-    }
-    if (const TemplateTypeParmType *TTP = T->getAs<TemplateTypeParmType>()) {
-      Out << 't' << TTP->getDepth() << '.' << TTP->getIndex();
-      return;
-    }
-    if (const TemplateSpecializationType *Spec
-                                    = T->getAs<TemplateSpecializationType>()) {
-      Out << '>';
-      VisitTemplateName(Spec->getTemplateName());
-      Out << Spec->getNumArgs();
-      for (unsigned I = 0, N = Spec->getNumArgs(); I != N; ++I)
-        VisitTemplateArgument(Spec->getArg(I));
-      return;
-    }
-    
-    // Unhandled type.
-    Out << ' ';
-    break;
-  } while (true);
-}
-
-void USRGenerator::VisitTemplateParameterList(
-                                         const TemplateParameterList *Params) {
-  if (!Params)
-    return;
-  Out << '>' << Params->size();
-  for (TemplateParameterList::const_iterator P = Params->begin(),
-                                          PEnd = Params->end();
-       P != PEnd; ++P) {
-    Out << '#';
-    if (isa<TemplateTypeParmDecl>(*P)) {
-      if (cast<TemplateTypeParmDecl>(*P)->isParameterPack())
-        Out<< 'p';
-      Out << 'T';
-      continue;
-    }
-    
-    if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(*P)) {
-      if (NTTP->isParameterPack())
-        Out << 'p';
-      Out << 'N';
-      VisitType(NTTP->getType());
-      continue;
-    }
-    
-    TemplateTemplateParmDecl *TTP = cast<TemplateTemplateParmDecl>(*P);
-    if (TTP->isParameterPack())
-      Out << 'p';
-    Out << 't';
-    VisitTemplateParameterList(TTP->getTemplateParameters());
-  }
-}
-
-void USRGenerator::VisitTemplateName(TemplateName Name) {
-  if (TemplateDecl *Template = Name.getAsTemplateDecl()) {
-    if (TemplateTemplateParmDecl *TTP
-                              = dyn_cast<TemplateTemplateParmDecl>(Template)) {
-      Out << 't' << TTP->getDepth() << '.' << TTP->getIndex();
-      return;
-    }
-    
-    Visit(Template);
-    return;
-  }
-  
-  // FIXME: Visit dependent template names.
-}
-
-void USRGenerator::VisitTemplateArgument(const TemplateArgument &Arg) {
-  switch (Arg.getKind()) {
-  case TemplateArgument::Null:
-    break;
-
-  case TemplateArgument::Declaration:
-    Visit(Arg.getAsDecl());
-    break;
-
-  case TemplateArgument::NullPtr:
-    break;
-
-  case TemplateArgument::TemplateExpansion:
-    Out << 'P'; // pack expansion of...
-    // Fall through
-  case TemplateArgument::Template:
-    VisitTemplateName(Arg.getAsTemplateOrTemplatePattern());
-    break;
-      
-  case TemplateArgument::Expression:
-    // FIXME: Visit expressions.
-    break;
-      
-  case TemplateArgument::Pack:
-    Out << 'p' << Arg.pack_size();
-    for (TemplateArgument::pack_iterator P = Arg.pack_begin(), PEnd = Arg.pack_end();
-         P != PEnd; ++P)
-      VisitTemplateArgument(*P);
-    break;
-      
-  case TemplateArgument::Type:
-    VisitType(Arg.getAsType());
-    break;
-      
-  case TemplateArgument::Integral:
-    Out << 'V';
-    VisitType(Arg.getIntegralType());
-    Out << Arg.getAsIntegral();
-    break;
-  }
-}
-
-//===----------------------------------------------------------------------===//
-// General purpose USR generation methods.
-//===----------------------------------------------------------------------===//
-
-void USRGenerator::GenObjCClass(StringRef cls) {
-  Out << "objc(cs)" << cls;
-}
-
-void USRGenerator::GenObjCCategory(StringRef cls, StringRef cat) {
-  Out << "objc(cy)" << cls << '@' << cat;
-}
-
-void USRGenerator::GenObjCIvar(StringRef ivar) {
-  Out << '@' << ivar;
-}
-
-void USRGenerator::GenObjCMethod(StringRef meth, bool isInstanceMethod) {
-  Out << (isInstanceMethod ? "(im)" : "(cm)") << meth;
-}
-
-void USRGenerator::GenObjCProperty(StringRef prop) {
-  Out << "(py)" << prop;
-}
-
-void USRGenerator::GenObjCProtocol(StringRef prot) {
-  Out << "objc(pl)" << prot;
-}
-
-//===----------------------------------------------------------------------===//
 // API hooks.
 //===----------------------------------------------------------------------===//
 
@@ -804,17 +30,7 @@ static inline StringRef extractUSRSuffix(StringRef s) {
 }
 
 bool cxcursor::getDeclCursorUSR(const Decl *D, SmallVectorImpl<char> &Buf) {
-  // Don't generate USRs for things with invalid locations.
-  if (!D || D->getLocStart().isInvalid())
-    return true;
-
-  USRGenerator UG(&D->getASTContext(), &Buf);
-  UG->Visit(D);
-
-  if (UG->ignoreResults())
-    return true;
-
-  return false;
+  return ide::generateUSRForDecl(D, Buf);
 }
 
 extern "C" {
@@ -856,12 +72,10 @@ CXString clang_getCursorUSR(CXCursor C) {
     if (!buf)
       return cxstring::createEmpty();
 
-    {
-      USRGenerator UG(&cxcursor::getCursorASTUnit(C)->getASTContext(),
-                      &buf->Data);
-      UG << "macro@"
-        << cxcursor::getCursorMacroDefinition(C)->getName()->getNameStart();
-    }
+    buf->Data += ide::getUSRSpacePrefix();
+    buf->Data += "macro@";
+    buf->Data +=
+        cxcursor::getCursorMacroDefinition(C)->getName()->getNameStart();
     buf->Data.push_back('\0');
     return createCXString(buf);
   }
@@ -870,46 +84,52 @@ CXString clang_getCursorUSR(CXCursor C) {
 }
 
 CXString clang_constructUSR_ObjCIvar(const char *name, CXString classUSR) {
-  USRGenerator UG;
-  UG << extractUSRSuffix(clang_getCString(classUSR));
-  UG->GenObjCIvar(name);
-  return cxstring::createDup(UG.str());
+  SmallString<128> Buf(ide::getUSRSpacePrefix());
+  llvm::raw_svector_ostream OS(Buf);
+  OS << extractUSRSuffix(clang_getCString(classUSR));
+  ide::generateUSRForObjCIvar(name, OS);
+  return cxstring::createDup(OS.str());
 }
 
 CXString clang_constructUSR_ObjCMethod(const char *name,
                                        unsigned isInstanceMethod,
                                        CXString classUSR) {
-  USRGenerator UG;
-  UG << extractUSRSuffix(clang_getCString(classUSR));
-  UG->GenObjCMethod(name, isInstanceMethod);
-  return cxstring::createDup(UG.str());
+  SmallString<128> Buf(ide::getUSRSpacePrefix());
+  llvm::raw_svector_ostream OS(Buf);
+  OS << extractUSRSuffix(clang_getCString(classUSR));
+  ide::generateUSRForObjCMethod(name, isInstanceMethod, OS);
+  return cxstring::createDup(OS.str());
 }
 
 CXString clang_constructUSR_ObjCClass(const char *name) {
-  USRGenerator UG;
-  UG->GenObjCClass(name);
-  return cxstring::createDup(UG.str());
+  SmallString<128> Buf(ide::getUSRSpacePrefix());
+  llvm::raw_svector_ostream OS(Buf);
+  ide::generateUSRForObjCClass(name, OS);
+  return cxstring::createDup(OS.str());
 }
 
 CXString clang_constructUSR_ObjCProtocol(const char *name) {
-  USRGenerator UG;
-  UG->GenObjCProtocol(name);
-  return cxstring::createDup(UG.str());
+  SmallString<128> Buf(ide::getUSRSpacePrefix());
+  llvm::raw_svector_ostream OS(Buf);
+  ide::generateUSRForObjCProtocol(name, OS);
+  return cxstring::createDup(OS.str());
 }
 
 CXString clang_constructUSR_ObjCCategory(const char *class_name,
                                          const char *category_name) {
-  USRGenerator UG;
-  UG->GenObjCCategory(class_name, category_name);
-  return cxstring::createDup(UG.str());
+  SmallString<128> Buf(ide::getUSRSpacePrefix());
+  llvm::raw_svector_ostream OS(Buf);
+  ide::generateUSRForObjCCategory(class_name, category_name, OS);
+  return cxstring::createDup(OS.str());
 }
 
 CXString clang_constructUSR_ObjCProperty(const char *property,
                                          CXString classUSR) {
-  USRGenerator UG;
-  UG << extractUSRSuffix(clang_getCString(classUSR));
-  UG->GenObjCProperty(property);
-  return cxstring::createDup(UG.str());
+  SmallString<128> Buf(ide::getUSRSpacePrefix());
+  llvm::raw_svector_ostream OS(Buf);
+  OS << extractUSRSuffix(clang_getCString(classUSR));
+  ide::generateUSRForObjCProperty(property, OS);
+  return cxstring::createDup(OS.str());
 }
 
 } // end extern "C"