Add a method for checking whether a function is one of the reserved global

placement allocation or deallocation functions.  These functions cannot be
replaced by the user and are exempt from the normal requirements on
allocation functions (e.g. that they must return unaliased memory).

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@131386 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/clang/AST/Decl.h b/include/clang/AST/Decl.h
index 6ca14ce8749645f0664b8106a22d40bcde91f3a9..e1dad644c9921e1eac77b5419236ff7992b91f44 100644 (file)
--- a/include/clang/AST/Decl.h
+++ b/include/clang/AST/Decl.h
@@ -1644,10 +1644,25 @@ public:
   bool isDeletedAsWritten() const { return IsDeleted && !IsDefaulted; }
   void setDeletedAsWritten(bool D = true) { IsDeleted = D; }
 
-  /// \brief Determines whether this is a function "main", which is
-  /// the entry point into an executable program.
+  /// \brief Determines whether this function is "main", which is the
+  /// entry point into an executable program.
   bool isMain() const;
 
+  /// \brief Determines whether this operator new or delete is one
+  /// of the reserved global placement operators:
+  ///    void *operator new(size_t, void *);
+  ///    void *operator new[](size_t, void *);
+  ///    void operator delete(void *, void *);
+  ///    void operator delete[](void *, void *);
+  /// These functions have special behavior under [new.delete.placement]:
+  ///    These functions are reserved, a C++ program may not define
+  ///    functions that displace the versions in the Standard C++ library.
+  ///    The provisions of [basic.stc.dynamic] do not apply to these
+  ///    reserved placement forms of operator new and operator delete.
+  ///
+  /// This function must be an allocation or deallocation function.
+  bool isReservedGlobalPlacementOperator() const;
+
   /// \brief Determines whether this function is a function with
   /// external, C linkage.
   bool isExternC() const;

diff --git a/lib/AST/Decl.cpp b/lib/AST/Decl.cpp
index d4df017383d1054a82f901cac0ca644cd5899b3b..1e98998002f2de866ab2ae02db9687b4593a0f43 100644 (file)
--- a/lib/AST/Decl.cpp
+++ b/lib/AST/Decl.cpp
@@ -1475,10 +1475,34 @@ void FunctionDecl::setPure(bool P) {
 }
 
 bool FunctionDecl::isMain() const {
-  ASTContext &Context = getASTContext();
-  return !Context.getLangOptions().Freestanding &&
-    getDeclContext()->getRedeclContext()->isTranslationUnit() &&
-    getIdentifier() && getIdentifier()->isStr("main");
+  const TranslationUnitDecl *tunit =
+    dyn_cast<TranslationUnitDecl>(getDeclContext()->getRedeclContext());
+  return tunit &&
+         tunit->getASTContext().getLangOptions().Freestanding &&
+         getIdentifier() &&
+         getIdentifier()->isStr("main");
+}
+
+bool FunctionDecl::isReservedGlobalPlacementOperator() const {
+  assert(getDeclName().getNameKind() == DeclarationName::CXXOperatorName);
+  assert(getDeclName().getCXXOverloadedOperator() == OO_New ||
+         getDeclName().getCXXOverloadedOperator() == OO_Delete ||
+         getDeclName().getCXXOverloadedOperator() == OO_Array_New ||
+         getDeclName().getCXXOverloadedOperator() == OO_Array_Delete);
+
+  if (isa<CXXRecordDecl>(getDeclContext())) return false;
+  assert(getDeclContext()->getRedeclContext()->isTranslationUnit());
+
+  const FunctionProtoType *proto = getType()->castAs<FunctionProtoType>();
+  if (proto->getNumArgs() != 2 || proto->isVariadic()) return false;
+
+  ASTContext &Context =
+    cast<TranslationUnitDecl>(getDeclContext()->getRedeclContext())
+      ->getASTContext();
+
+  // The result type and first argument type are constant across all
+  // these operators.  The second argument must be exactly void*.
+  return (proto->getArgType(1).getCanonicalType() == Context.VoidPtrTy);
 }
 
 bool FunctionDecl::isExternC() const {