ada: Accept static strings with External_Initialization

Before this patch, the argument to the External_Initialization aspect
had to be a string literal. This patch extends the possibilities so that
any static string is accepted.

A new helper function, Is_OK_Static_Expression_Of_Type, is introduced,
and in addition to the main change of this patch a couple of calls to
that helper function are added in other places to replace equivalent
inline code.

gcc/ada/ChangeLog:

	* sem_eval.ads (Is_OK_Static_Expression_Of_Type): New function.
	* sem_eval.adb (Is_OK_Static_Expression_Of_Type): Likewise.
	* sem_ch13.adb (Check_Expr_Is_OK_Static_Expression): Use new function.
	* sem_prag.adb (Check_Expr_Is_OK_Static_Expression): Likewise.
	* sem_ch3.adb (Apply_External_Initialization): Accept static strings
	for the parameter.

1 files changed, 9 insertions, 0 deletions

diff --git a/gcc/ada/sem_eval.ads b/gcc/ada/sem_eval.ads
index b79f61f..177a3e2 100644
--- a/gcc/ada/sem_eval.ads
+++ b/gcc/ada/sem_eval.ads
@@ -422,6 +422,15 @@ package Sem_Eval is
    --  for compile time evaluation purposes. Use Compile_Time_Known_Value
    --  instead (see section on "Compile-Time Known Values" above).
 
+   type Staticity is (Static, Not_Static, Invalid);
+
+   function Is_OK_Static_Expression_Of_Type
+     (Expr : Node_Id; Typ : Entity_Id := Empty) return Staticity;
+   --  Return whether Expr is a static expression of the given type (i.e. it
+   --  will be analyzed and resolved using this type, which can be any valid
+   --  argument to Resolve, e.g. Any_Integer is OK). Includes checking that the
+   --  expression does not raise Constraint_Error.
+
    function Is_OK_Static_Range (N : Node_Id) return Boolean;
    --  Determines if range is static, as defined in RM 4.9(26), and also checks
    --  that neither bound of the range raises constraint error, thus ensuring