[AST] Convert MangleNumberingContext to a unique_ptr.

[jlebar]

Summary

It doesn't need to be refcounted anymore, either.

[timshen]

clang/include/clang/Sema/Sema.h

879

Wait, what?

This is awesome. :)

[jlebar]

https://github.com/llvm-mirror/clang/commit/7c4b8c0a7921b999f5a73d6ba47ee8350676f747

clang/include/clang/AST/ASTContext.h

private:
   /// don't override anything, we store the overridden functions in
   /// this map on the side rather than within the CXXMethodDecl structure.
   typedef llvm::TinyPtrVector<const CXXMethodDecl*> CXXMethodVector;
   llvm::DenseMap<const CXXMethodDecl *, CXXMethodVector> OverriddenMethods;
 
   /// \brief Mapping from each declaration context to its corresponding
   /// mangling numbering context (used for constructs like lambdas which
   /// need to be consistently numbered for the mangler).
-  llvm::DenseMap<const DeclContext *, MangleNumberingContext *>
+  llvm::DenseMap<const DeclContext *, std::unique_ptr<MangleNumberingContext>>
       MangleNumberingContexts;
 
   /// \brief Side-table of mangling numbers for declarations which rarely
   /// need them (like static local vars).
   llvm::MapVector<const NamedDecl *, unsigned> MangleNumbers;
   llvm::MapVector<const VarDecl *, unsigned> StaticLocalNumbers;
 
   /// \brief Mapping that stores parameterIndex values for ParmVarDecls when
public:
 
   void setStaticLocalNumber(const VarDecl *VD, unsigned Number);
   unsigned getStaticLocalNumber(const VarDecl *VD) const;
 
   /// \brief Retrieve the context for computing mangling numbers in the given
   /// DeclContext.
   MangleNumberingContext &getManglingNumberContext(const DeclContext *DC);
 
-  MangleNumberingContext *createMangleNumberingContext() const;
+  std::unique_ptr<MangleNumberingContext> createMangleNumberingContext() const;
 
   /// \brief Used by ParmVarDecl to store on the side the
   /// index of the parameter when it exceeds the size of the normal bitfield.
   void setParameterIndex(const ParmVarDecl *D, unsigned index);
 
   /// \brief Used by ParmVarDecl to retrieve on the side the
   /// index of the parameter when it exceeds the size of the normal bitfield.
   unsigned getParameterIndex(const ParmVarDecl *D) const;

clang/include/clang/AST/MangleNumberingContext.h

 class CXXMethodDecl;
 class IdentifierInfo;
 class TagDecl;
 class Type;
 class VarDecl;
 
 /// \brief Keeps track of the mangled names of lambda expressions and block
 /// literals within a particular context.
-class MangleNumberingContext : public RefCountedBase<MangleNumberingContext> {
+class MangleNumberingContext {
 public:
   virtual ~MangleNumberingContext() {}
 
   /// \brief Retrieve the mangling number of a new lambda expression with the
   /// given call operator within this context.
   virtual unsigned getManglingNumber(const CXXMethodDecl *CallOperator) = 0;
 
   /// \brief Retrieve the mangling number of a new block literal within this

clang/include/clang/Sema/Sema.h

struct ExpressionEvaluationContextRecord {
     /// suffice, e.g., in a default function argument.
     Decl *ManglingContextDecl;
 
     /// \brief The context information used to mangle lambda expressions
     /// and block literals within this context.
     ///
     /// This mangling information is allocated lazily, since most contexts
     /// do not have lambda expressions or block literals.
-    IntrusiveRefCntPtr<MangleNumberingContext> MangleNumbering;
+    std::unique_ptr<MangleNumberingContext> MangleNumbering;
 
     /// \brief If we are processing a decltype type, a set of call expressions
     /// for which we have deferred checking the completeness of the return type.
     SmallVector<CallExpr *, 8> DelayedDecltypeCalls;
 
     /// \brief If we are processing a decltype type, a set of temporary binding
     /// expressions for which we have deferred checking the destructor.
     SmallVector<CXXBindTemporaryExpr *, 8> DelayedDecltypeBinds;

clang/lib/AST/ASTContext.cpp

for (llvm::DenseMap<const Decl*, AttrVec*>::iterator A = DeclAttrs.begin(),
     A->second->~AttrVec();
 
   for (std::pair<const MaterializeTemporaryExpr *, APValue *> &MTVPair :
        MaterializedTemporaryValues)
     MTVPair.second->~APValue();
 
   for (const auto &Value : ModuleInitializers)
     Value.second->~PerModuleInitializers();
-
-  llvm::DeleteContainerSeconds(MangleNumberingContexts);
 }
 
 void ASTContext::ReleaseParentMapEntries() {
   if (!PointerParents) return;
   for (const auto &Entry : *PointerParents) {
     if (Entry.second.is<ast_type_traits::DynTypedNode *>()) {
       delete Entry.second.get<ast_type_traits::DynTypedNode *>();
     } else if (Entry.second.is<ParentVector *>()) {

 unsigned ASTContext::getStaticLocalNumber(const VarDecl *VD) const {
   auto I = StaticLocalNumbers.find(VD);
   return I != StaticLocalNumbers.end() ? I->second : 1;
 }
 
 MangleNumberingContext &
 ASTContext::getManglingNumberContext(const DeclContext *DC) {
   assert(LangOpts.CPlusPlus);  // We don't need mangling numbers for plain C.
-  MangleNumberingContext *&MCtx = MangleNumberingContexts[DC];
+  std::unique_ptr<MangleNumberingContext> &MCtx = MangleNumberingContexts[DC];
   if (!MCtx)
     MCtx = createMangleNumberingContext();
   return *MCtx;
 }
 
-MangleNumberingContext *ASTContext::createMangleNumberingContext() const {
+std::unique_ptr<MangleNumberingContext>
+ASTContext::createMangleNumberingContext() const {
   return ABI->createMangleNumberingContext();
 }
 
 const CXXConstructorDecl *
 ASTContext::getCopyConstructorForExceptionObject(CXXRecordDecl *RD) {
   return ABI->getCopyConstructorForExceptionObject(
       cast<CXXRecordDecl>(RD->getFirstDecl()));
 }

clang/lib/AST/CXXABI.h

public:
   /// Returns the default calling convention for C++ methods.
   virtual CallingConv getDefaultMethodCallConv(bool isVariadic) const = 0;
 
   /// Returns whether the given class is nearly empty, with just virtual
   /// pointers and no data except possibly virtual bases.
   virtual bool isNearlyEmpty(const CXXRecordDecl *RD) const = 0;
 
   /// Returns a new mangling number context for this C++ ABI.
-  virtual MangleNumberingContext *createMangleNumberingContext() const = 0;
+  virtual std::unique_ptr<MangleNumberingContext>
+  createMangleNumberingContext() const = 0;
 
   /// Adds a mapping from class to copy constructor for this C++ ABI.
   virtual void addCopyConstructorForExceptionObject(CXXRecordDecl *,
                                                     CXXConstructorDecl *) = 0;
 
   /// Retrieves the mapping from class to copy constructor for this C++ ABI.
   virtual const CXXConstructorDecl *
   getCopyConstructorForExceptionObject(CXXRecordDecl *) = 0;

clang/lib/AST/ItaniumCXXABI.cpp

public:
 
   void addDeclaratorForUnnamedTagDecl(TagDecl *TD,
                                       DeclaratorDecl *DD) override {}
 
   DeclaratorDecl *getDeclaratorForUnnamedTagDecl(const TagDecl *TD) override {
     return nullptr;
   }
 
-  MangleNumberingContext *createMangleNumberingContext() const override {
-    return new ItaniumNumberingContext();
+  std::unique_ptr<MangleNumberingContext>
+  createMangleNumberingContext() const override {
+    return llvm::make_unique<ItaniumNumberingContext>();
   }
 };
 }
 
 CXXABI *clang::CreateItaniumCXXABI(ASTContext &Ctx) {
   return new ItaniumCXXABI(Ctx);
 }

clang/lib/AST/MicrosoftCXXABI.cpp

if (!I)
       I = DD;
   }
 
   DeclaratorDecl *getDeclaratorForUnnamedTagDecl(const TagDecl *TD) override {
     return UnnamedTagDeclToDeclaratorDecl.lookup(
         const_cast<TagDecl *>(TD->getCanonicalDecl()));
   }
 
-  MangleNumberingContext *createMangleNumberingContext() const override {
-    return new MicrosoftNumberingContext();
+  std::unique_ptr<MangleNumberingContext>
+  createMangleNumberingContext() const override {
+    return llvm::make_unique<MicrosoftNumberingContext>();
   }
 };
 }
 
 // getNumBases() seems to only give us the number of direct bases, and not the
 // total.  This function tells us if we inherit from anybody that uses MI, or if
 // we have a non-primary base class, which uses the multiple inheritance model.
 static bool usesMultipleInheritanceModel(const CXXRecordDecl *RD) {