Downgrade deletion of a void* from an error (which is should be) to an

extension warning (which other compilers seem to use). Works around a
known bug in Xalan.

llvm-svn: 104509

Author: DougGregor

clang/include/clang/Basic/DiagnosticSemaKinds.td

@@ -2262,6 +2262,8 @@ def err_default_init_const : Error<
   "default initialization of an object of const type %0"
   "%select{| requires a user-provided default constructor}1">;
 def err_delete_operand : Error<"cannot delete expression of type %0">;
+def ext_delete_void_ptr_operand : ExtWarn<
+  "cannot delete expression with pointer-to-'void' type %0">;
 def err_ambiguous_delete_operand : Error<"ambiguous conversion of delete "
                                          "expression of type %0 to a pointer">;
 def warn_delete_incomplete : Warning<

clang/lib/Sema/SemaExprCXX.cpp

@@ -1398,7 +1398,13 @@ Sema::ActOnCXXDelete(SourceLocation StartLoc, bool UseGlobal,
         << Type << Ex->getSourceRange());
 
     QualType Pointee = Type->getAs<PointerType>()->getPointeeType();
-    if (Pointee->isFunctionType() || Pointee->isVoidType())
+    if (Pointee->isVoidType() && !isSFINAEContext()) {
+      // The C++ standard bans deleting a pointer to a non-object type, which 
+      // effectively bans deletion of "void*". However, most compilers support
+      // this, so we treat it as a warning unless we're in a SFINAE context.
+      Diag(StartLoc, diag::ext_delete_void_ptr_operand)
+        << Type << Ex->getSourceRange();
+    } else if (Pointee->isFunctionType() || Pointee->isVoidType())
       return ExprError(Diag(StartLoc, diag::err_delete_operand)
         << Type << Ex->getSourceRange());
     else if (!Pointee->isDependentType() &&

clang/test/SemaCXX/new-delete.cpp

@@ -103,7 +103,7 @@ void bad_deletes()
   delete 0; // expected-error {{cannot delete expression of type 'int'}}
   delete [0] (int*)0; // expected-error {{expected ']'}} \
                       // expected-note {{to match this '['}}
-  delete (void*)0; // expected-error {{cannot delete expression}}
+  delete (void*)0; // expected-warning {{cannot delete expression with pointer-to-'void' type 'void *'}}
   delete (T*)0; // expected-warning {{deleting pointer to incomplete type}}
   ::S::delete (int*)0; // expected-error {{expected unqualified-id}}
 }