[cfe-commits] r144056 - in /cfe/trunk: lib/AST/Expr.cpp lib/AST/ExprConstant.cpp test/SemaCXX/constant-expression-cxx11.cpp test/SemaCXX/constant-expression.cpp

[Eli Friedman]

On Mon, Nov 7, 2011 at 5:31 PM, Richard Smith
<richard-llvm at metafoo.co.uk> wrote:
> Author: rsmith
> Date: Mon Nov  7 19:31:09 2011
> New Revision: 144056
>
> URL: http://llvm.org/viewvc/llvm-project?rev=144056&view=rev
> Log:
> Fix a cluster of related issues involving value-dependence and constant
> expression evaluation:
>  - When folding a non-value-dependent expression, we may try to use the
>   initializer of a value-dependent variable. If that happens, give up.
>  - In C++98, actually check that a const, non-volatile DeclRefExpr inside an ICE
>   is of integral or enumeration type (a reference isn't OK!)
>  - In C++11, DeclRefExprs for objects of const literal type initialized with
>   value-dependent expressions are themselves value-dependent.
>  - So are references initialized with value-dependent expressions (though this
>   case is missing from the C++11 standard, along with many others).
>
> Modified:
>    cfe/trunk/lib/AST/Expr.cpp
>    cfe/trunk/lib/AST/ExprConstant.cpp
>    cfe/trunk/test/SemaCXX/constant-expression-cxx11.cpp
>    cfe/trunk/test/SemaCXX/constant-expression.cpp
>
> Modified: cfe/trunk/lib/AST/Expr.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/Expr.cpp?rev=144056&r1=144055&r2=144056&view=diff
> ==============================================================================
> --- cfe/trunk/lib/AST/Expr.cpp (original)
> +++ cfe/trunk/lib/AST/Expr.cpp Mon Nov  7 19:31:09 2011
> @@ -185,21 +185,29 @@
>
>   //  (VD) - a constant with integral or enumeration type and is
>   //         initialized with an expression that is value-dependent.
> +  //  (VD) - a constant with literal type and is initialized with an
> +  //         expression that is value-dependent [C++11].
> +  //  (VD) - FIXME: Missing from the standard:
> +  //       -  an entity with reference type and is initialized with an
> +  //          expression that is value-dependent [C++11]
>   if (VarDecl *Var = dyn_cast<VarDecl>(D)) {
> -    if (Var->getType()->isIntegralOrEnumerationType() &&
> -        Var->getType().getCVRQualifiers() == Qualifiers::Const) {
> +    if ((D->getASTContext().getLangOptions().CPlusPlus0x ?
> +           Var->getType()->isLiteralType() :
> +           Var->getType()->isIntegralOrEnumerationType()) &&
> +        (Var->getType().getCVRQualifiers() == Qualifiers::Const ||
> +         Var->getType()->isReferenceType())) {
>       if (const Expr *Init = Var->getAnyInitializer())
>         if (Init->isValueDependent()) {
>           ValueDependent = true;
>           InstantiationDependent = true;
>         }
> -    }
> -
> +    }
> +
>     // (VD) - FIXME: Missing from the standard:
>     //      -  a member function or a static data member of the current
>     //         instantiation
> -    else if (Var->isStaticDataMember() &&
> -             Var->getDeclContext()->isDependentContext()) {
> +    if (Var->isStaticDataMember() &&
> +        Var->getDeclContext()->isDependentContext()) {
>       ValueDependent = true;
>       InstantiationDependent = true;
>     }
> @@ -213,8 +221,7 @@
>   if (isa<CXXMethodDecl>(D) && D->getDeclContext()->isDependentContext()) {
>     ValueDependent = true;
>     InstantiationDependent = true;
> -    return;
> -  }
> +  }
>  }
>
>  void DeclRefExpr::computeDependence() {
>
> Modified: cfe/trunk/lib/AST/ExprConstant.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/ExprConstant.cpp?rev=144056&r1=144055&r2=144056&view=diff
> ==============================================================================
> --- cfe/trunk/lib/AST/ExprConstant.cpp (original)
> +++ cfe/trunk/lib/AST/ExprConstant.cpp Mon Nov  7 19:31:09 2011
> @@ -552,7 +552,7 @@
>     return false;
>
>   const Expr *Init = VD->getAnyInitializer();
> -  if (!Init)
> +  if (!Init || Init->isValueDependent())
>     return false;

Is this check actually necessary?  We shouldn't be querying ICEness on
a value-dependent expression.

-Eli