Issue: #397

#397
Partial commit.
Added a call to handle NT_CHECKED initializers. If the type of the declaration requires NT_CHECKED, the last item in the initializer list is validated to make sure it is null (nullptr, NULL, 0 or '\0' depending on what's appropriate).

Pending:
1. Handle all types (Constant char arrays are not handled yet.)
2. Tests (Add tests for ptr to NT_CHECKED types, NT_CHECKED array, Struct that contains one or both of the previous two cases)
3. Error handling. The current version of the compiler crashes if the NT_CHECKED array is not null terminated.

Author: Prabhuk

include/clang/AST/Expr.h

@@ -4408,6 +4408,15 @@ class InitListExpr : public Expr {
   /// idiomatic?
   bool isIdiomaticZeroInitializer(const LangOptions &LangOpts) const;
 
+  /// If the Type of InitListExpr is _NT_CHECKED array or pointer to _NT_CHECKED array
+  /// the initializer must end with null terminator. Returns true if null terminator is
+  /// not required, or if null terminator is required and it exists.
+  /// Returns false if null terminator is missing for _NT_CHECKED array or pointer to _NT_CHECKED
+  /// array types
+  bool handleNullTerminationCheck(ASTContext &C,
+                                  const InitListExpr *Init,
+                                  QualType VDeclType) const;
+
   SourceLocation getLBraceLoc() const { return LBraceLoc; }
   void setLBraceLoc(SourceLocation Loc) { LBraceLoc = Loc; }
   SourceLocation getRBraceLoc() const { return RBraceLoc; }

lib/AST/Expr.cpp

@@ -2001,6 +2001,33 @@ bool InitListExpr::isIdiomaticZeroInitializer(const LangOptions &LangOpts) const
   return Lit && Lit->getValue() == 0;
 }
 
+bool InitListExpr::handleNullTerminationCheck(ASTContext &C, const InitListExpr *Init, QualType VDeclType) const {
+  //Init->dump();
+  QualType T = Init->getType();
+  // Null termination required only for _NT_CHECKED arrays and for pointers to
+  // _NT_CHECKED arrays
+  if (!VDeclType->isNtCheckedArrayType()) {
+    if (!T->isCheckedPointerNtArrayType()) {
+      return true;
+    }
+  }
+
+  assert(isSemanticForm() && "Null terminator check must be performed "
+                             "after all the initialization of all "
+                             "subobjects are made explicit");
+
+  const Expr *LastItem = getInit(InitExprs.size() - 1);
+  /*if (T->isCheckedPointerArrayType()) {
+
+  } else if (T->isNtCheckedArrayType()) {
+	  LastItem->isNu
+
+  }*/
+  Expr::NullPointerConstantKind E = LastItem->isNullPointerConstant(C, Expr::NPC_ValueDependentIsNull);
+  return E != NPCK_NotNull;
+  //return LastItem == NULL;
+}
+
 SourceLocation InitListExpr::getLocStart() const {
   if (InitListExpr *SyntacticForm = getSyntacticForm())
     return SyntacticForm->getLocStart();

lib/Sema/SemaDecl.cpp

@@ -10925,6 +10925,17 @@ void Sema::AddInitializerToDecl(Decl *RealDecl, Expr *Init, bool DirectInit,
       VDecl->setInvalidDecl();
   }
 
+  if (InitListExpr *E = dyn_cast<InitListExpr>(Init)) {
+    /// $TODO$ Remove dump calls.
+    /// $TODO$ Handle constant string types (char array)
+    //Init->dump();
+    //RealDecl->is
+    if (!E->handleNullTerminationCheck(RealDecl->getASTContext(), E, VDecl->getType())) {
+      RealDecl->setInvalidDecl();
+      return;
+    }
+  }
+
   // If adding the initializer will turn this declaration into a definition,
   // and we already have a definition for this variable, diagnose or otherwise
   // handle the situation.
@@ -11394,47 +11405,47 @@ void Sema::ActOnUninitializedDecl(Decl *RealDecl) {
       else if (B && !B->isInvalid() && !B->isUnknown() && !Ty->isArrayType())
         Diag(Var->getLocation(), diag::err_initializer_expected_with_bounds)
           << Var;
-
-      // An unchecked pointer in a checked scope with a bounds expression must be initialized
-      if (Ty->isUncheckedPointerType() && InCheckedScope && Var->hasBoundsExpr())
-        Diag(Var->getLocation(), diag::err_initializer_expected_for_unchecked_pointer_in_checked_scope_with_bounds_expr)
-          << Var;
-
-      // An integer with a bounds expression must be initialized
-      if (Ty->isIntegerType() && Var->hasBoundsExpr())
-        Diag(Var->getLocation(), diag::err_initializer_expected_for_integer_with_bounds_expr)
-          << Var;
-
-      // struct/union and array with checked pointer members must have initializers 
-      // array with checked ptr element
-      if (Ty->isArrayType()) {
-        // if this is an array type, check the element type of the array, potentially with type qualifiers missing
-        if (Type::HasCheckedValue == Ty->getPointeeOrArrayElementType()->containsCheckedValue(InCheckedScope))
-          Diag(Var->getLocation(), diag::err_initializer_expected_for_array)
-          << Var;
-      }
-      // RecordType(struct/union) with checked pointer member
-      if (Ty->isRecordType()) {
-        const RecordType *RT = Ty->getAs<RecordType>();
-        switch (RT->containsCheckedValue(InCheckedScope)) {
-        default: 
-          break;  
-        case Type::HasCheckedValue: {
-          Diag(Var->getLocation(), diag::err_initializer_expected_for_record_with_checked_value)
-          << RT->getDecl()->getTagKind() << Var;
-          break;
-        }
-        case Type::HasIntWithBounds: {
-          Diag(Var->getLocation(), diag::err_initializer_expected_for_record_with_integer_member_with_bounds_expr)
-          << RT->getDecl()->getTagKind() << Var;
-          break;
-        }
-        case Type::HasUncheckedPointer: {
-          Diag(Var->getLocation(), diag::err_initializer_expected_for_record_with_unchecked_pointer_in_checked_scope)
-          << RT->getDecl()->getTagKind() << Var;       
-          break;
-        }       
-        }
+
+      // An unchecked pointer in a checked scope with a bounds expression must be initialized
+      if (Ty->isUncheckedPointerType() && InCheckedScope && Var->hasBoundsExpr())
+        Diag(Var->getLocation(), diag::err_initializer_expected_for_unchecked_pointer_in_checked_scope_with_bounds_expr)
+          << Var;
+
+      // An integer with a bounds expression must be initialized
+      if (Ty->isIntegerType() && Var->hasBoundsExpr())
+        Diag(Var->getLocation(), diag::err_initializer_expected_for_integer_with_bounds_expr)
+          << Var;
+
+      // struct/union and array with checked pointer members must have initializers 
+      // array with checked ptr element
+      if (Ty->isArrayType()) {
+        // if this is an array type, check the element type of the array, potentially with type qualifiers missing
+        if (Type::HasCheckedValue == Ty->getPointeeOrArrayElementType()->containsCheckedValue(InCheckedScope))
+          Diag(Var->getLocation(), diag::err_initializer_expected_for_array)
+          << Var;
+      }
+      // RecordType(struct/union) with checked pointer member
+      if (Ty->isRecordType()) {
+        const RecordType *RT = Ty->getAs<RecordType>();
+        switch (RT->containsCheckedValue(InCheckedScope)) {
+        default: 
+          break;  
+        case Type::HasCheckedValue: {
+          Diag(Var->getLocation(), diag::err_initializer_expected_for_record_with_checked_value)
+          << RT->getDecl()->getTagKind() << Var;
+          break;
+        }
+        case Type::HasIntWithBounds: {
+          Diag(Var->getLocation(), diag::err_initializer_expected_for_record_with_integer_member_with_bounds_expr)
+          << RT->getDecl()->getTagKind() << Var;
+          break;
+        }
+        case Type::HasUncheckedPointer: {
+          Diag(Var->getLocation(), diag::err_initializer_expected_for_record_with_unchecked_pointer_in_checked_scope)
+          << RT->getDecl()->getTagKind() << Var;       
+          break;
+        }       
+        }
       }
     }