[cfe-dev] better way to test for explicit C++ constructor?

[Eli Friedman]

On Tue, Dec 11, 2012 at 12:28 PM, Peeter Joot <peeter.joot at gmail.com> wrote:
> I needed to hunt down code that uses explicit global constructors.  I was
> able to do this, for example, identifing global1 in the following:
>
> struct withConstructor
> {
>    int x ;
>
>    withConstructor() : x(3) {}
> } ;
>
> struct noConstructor
> {
>    int x ;
> } ;
>
> void foo()
> {
>    withConstructor local1 ;
>    noConstructor local2 ;
> }
>
> withConstructor global1 ;
> noConstructor global2 ;

Here's the code used to implement -Wglobal-constructor:

  Expr *Init = var->getInit();
  bool IsGlobal = var->hasGlobalStorage() && !var->isStaticLocal();
  QualType baseType = Context.getBaseElementType(type);

  if (!var->getDeclContext()->isDependentContext() &&
      Init && !Init->isValueDependent()) {
    if (IsGlobal && !var->isConstexpr() &&
        getDiagnostics().getDiagnosticLevel(diag::warn_global_constructor,
                                            var->getLocation())
          != DiagnosticsEngine::Ignored &&
        !Init->isConstantInitializer(Context, baseType->isReferenceType()))
      Diag(var->getLocation(), diag::warn_global_constructor)
        << Init->getSourceRange();

-Eli