This patch modifies the analysis of pragma Independent_Components to account
for a side effect from handling of self-referential records which render the
pragma illegal.
------------
-- Source --
------------
-- pack.ads
package Pack is
type OK is record
Comp_1 : Integer;
Comp_2 : access OK;
end record;
pragma Independent_Components (OK);
type Error;
pragma Independent_Components (Error);
type Error is record
Comp : Integer;
end record;
end Pack;
----------------------------
-- Compilation and output --
----------------------------
$ gcc -c pack.ads
pack.ads:9:04: representation item must be after full type declaration
Tested on x86_64-pc-linux-gnu, committed on trunk
2018-05-24 Hristian Kirtchev <kirtc...@adacore.com>
gcc/ada/
* sem_prag.adb (Analyze_Pragma): Use the full view of an internally
generated incomplete type.--- gcc/ada/sem_prag.adb
+++ gcc/ada/sem_prag.adb
@@ -16999,6 +16999,38 @@ package body Sem_Prag is
E := Entity (E_Id);
+ -- A record type with a self-referential component of anonymous
+ -- access type is given an incomplete view in order to handle the
+ -- self reference:
+ --
+ -- type Rec is record
+ -- Self : access Rec;
+ -- end record;
+ --
+ -- becomes
+ --
+ -- type Rec;
+ -- type Ptr is access Rec;
+ -- type Rec is record
+ -- Self : Ptr;
+ -- end record;
+ --
+ -- Since the incomplete view is now the initial view of the type,
+ -- the argument of the pragma will reference the incomplete view,
+ -- but this view is illegal according to the semantics of the
+ -- pragma.
+ --
+ -- Obtain the full view of an internally-generated incomplete type
+ -- only. This way an attempt to associate the pragma with a source
+ -- incomplete type is still caught.
+
+ if Ekind (E) = E_Incomplete_Type
+ and then not Comes_From_Source (E)
+ and then Present (Full_View (E))
+ then
+ E := Full_View (E);
+ end if;
+
-- A pragma that applies to a Ghost entity becomes Ghost for the
-- purposes of legality checks and removal of ignored Ghost code.
