Introduce CXXRecordDecl::isCLike() that is true if the class is C-like,
without C++-specific features.

Use it to set the language to C++ when indexing non-C-like structs.
rdar://10732579

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@148708 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/clang/AST/DeclCXX.h b/include/clang/AST/DeclCXX.h
index 6592e1b..e035e0b 100644
--- a/include/clang/AST/DeclCXX.h
+++ b/include/clang/AST/DeclCXX.h
@@ -348,6 +348,9 @@
     /// \brief True if this class (or any subobject) has mutable fields.
     bool HasMutableFields : 1;
 
+    /// \brief True if there no non-field members declared by the user.
+    bool HasOnlyFields : 1;
+
     /// HasTrivialDefaultConstructor - True when, if this class has a default
     /// constructor, this default constructor is trivial.
     ///
@@ -962,6 +965,10 @@
   /// user-defined destructor.
   bool isPOD() const { return data().PlainOldData; }
 
+  /// \brief True if this class is C-like, without C++-specific features, e.g.
+  /// it contains only public fields, no bases, tag kind is not 'class', etc.
+  bool isCLike() const;
+
   /// isEmpty - Whether this class is empty (C++0x [meta.unary.prop]), which
   /// means it has a virtual function, virtual base, data member (other than
   /// 0-width bit-field) or inherits from a non-empty class. Does NOT include
diff --git a/lib/AST/DeclCXX.cpp b/lib/AST/DeclCXX.cpp
index b09b672..7cf7bf1 100644
--- a/lib/AST/DeclCXX.cpp
+++ b/lib/AST/DeclCXX.cpp
@@ -43,7 +43,8 @@
     Aggregate(true), PlainOldData(true), Empty(true), Polymorphic(false),
     Abstract(false), IsStandardLayout(true), HasNoNonEmptyBases(true),
     HasPrivateFields(false), HasProtectedFields(false), HasPublicFields(false),
-    HasMutableFields(false), HasTrivialDefaultConstructor(true),
+    HasMutableFields(false), HasOnlyFields(true),
+    HasTrivialDefaultConstructor(true),
     HasConstexprNonCopyMoveConstructor(false),
     DefaultedDefaultConstructorIsConstexpr(true),
     DefaultedCopyConstructorIsConstexpr(true),
@@ -456,6 +457,9 @@
 }
 
 void CXXRecordDecl::addedMember(Decl *D) {
+  if (!isa<FieldDecl>(D) && !isa<IndirectFieldDecl>(D) && !D->isImplicit())
+    data().HasOnlyFields = false;
+
   // Ignore friends and invalid declarations.
   if (D->getFriendObjectKind() || D->isInvalidDecl())
     return;
@@ -957,6 +961,18 @@
       data().Conversions.addDecl(Shadow, Shadow->getAccess());
 }
 
+bool CXXRecordDecl::isCLike() const {
+  if (getTagKind() == TTK_Class || !TemplateOrInstantiation.isNull())
+    return false;
+  if (!hasDefinition())
+    return true;
+
+  return data().HasOnlyFields &&
+      !data().HasPrivateFields &&
+      !data().HasProtectedFields &&
+      !data().NumBases;
+}
+
 static CanQualType GetConversionType(ASTContext &Context, NamedDecl *Conv) {
   QualType T;
   if (isa<UsingShadowDecl>(Conv))
diff --git a/tools/libclang/IndexingContext.cpp b/tools/libclang/IndexingContext.cpp
index 3d70144..a124cbd 100644
--- a/tools/libclang/IndexingContext.cpp
+++ b/tools/libclang/IndexingContext.cpp
@@ -814,12 +814,9 @@
       EntityInfo.kind = CXIdxEntity_Enum; break;
     }
 
-    if (const CXXRecordDecl *CXXRec = dyn_cast<CXXRecordDecl>(D)) {
-      // FIXME: isPOD check is not sufficient, a POD can contain methods,
-      // we want a isCStructLike check.
-      if (CXXRec->hasDefinition() && !CXXRec->isPOD())
+    if (const CXXRecordDecl *CXXRec = dyn_cast<CXXRecordDecl>(D))
+      if (!CXXRec->isCLike())
         EntityInfo.lang = CXIdxEntityLang_CXX;
-    }
 
     if (isa<ClassTemplatePartialSpecializationDecl>(D)) {
       EntityInfo.templateKind = CXIdxEntity_TemplatePartialSpecialization;