In Ada 2012, boolean aspects are True by default, but can specify explicitly
a value of False. In the case of an Import aspect, this indicates that the
corresponding entity must have a completion in Ada, and not in the language
specified in a Convention aspect.
Compiling main.adb must yield:
main.adb:4:04: missing body for "Get_Length"
---
with Interfaces.C; with Ada.Text_IO;
procedure Main is
function Get_Length return Interfaces.C.size_t with
Convention => C,
Import => False,
External_Name => "getLength";
begin
Ada.Text_IO.Put_Line(Get_Length'Img);
end Main;
Tested on x86_64-pc-linux-gnu, committed on trunk
2014-08-04 Ed Schonberg <schonb...@adacore.com>
* sem_prag.adb (Process_Import_Or_Interface): Handle properly
an aspect Import that specifies a False value.
Index: sem_prag.adb
===================================================================
--- sem_prag.adb (revision 213553)
+++ sem_prag.adb (working copy)
@@ -7993,7 +7993,37 @@
end if;
end;
- Set_Has_Completion (Def_Id);
+ -- If the pragma comes from an aspect specification, there
+ -- must be an Import aspect specified as well. In the rare
+ -- case where Import is set to False, the suprogram needs to
+ -- have a local completion.
+
+ declare
+ Imp_Aspect : constant Node_Id :=
+ Find_Aspect (Def_Id, Aspect_Import);
+ Expr : Node_Id;
+
+ begin
+ if Present (Imp_Aspect)
+ and then Present (Expression (Imp_Aspect))
+ then
+ Expr := Expression (Imp_Aspect);
+ Analyze_And_Resolve (Expr, Standard_Boolean);
+
+ if Is_Entity_Name (Expr)
+ and then Entity (Expr) = Standard_True
+ then
+ Set_Has_Completion (Def_Id);
+ end if;
+
+ -- If there is no expression, the default is True, as for
+ -- all boolean aspects. Same for the older pragma.
+
+ else
+ Set_Has_Completion (Def_Id);
+ end if;
+ end;
+
Process_Interface_Name (Def_Id, Arg3, Arg4);
end if;
