From a08f366ae875ae70fba5014c94956cdbf7bf91db Mon Sep 17 00:00:00 2001 From: Javier Miranda Date: Tue, 15 Mar 2022 13:20:24 -0700 Subject: [PATCH] [Ada] Implement calls to abstract subprograms in class-wide pre/post-conditions In some special cases involving class-wide pre/post conditions, Ada allows a non-dispatching call to an abstract function (which is usually illegal). Fix a bug in the implementation of Ada's rules about the run-time behavior of such a call. Thanks to Javier Miranda for producing this patch. gcc/ada/ * contracts.adb (Build_Call_Helper_Body): Improve handling of the case of a (legal) non-dispatching call to an abstract subprogram. --- gcc/ada/contracts.adb | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/gcc/ada/contracts.adb b/gcc/ada/contracts.adb index 7ce3cfac91d..9463642556f 100644 --- a/gcc/ada/contracts.adb +++ b/gcc/ada/contracts.adb @@ -3899,7 +3899,16 @@ package body Contracts is Set_Corresponding_Body (Helper_Decl, Body_Id); Set_Must_Override (Body_Spec, False); - if Present (Class_Preconditions (Subp_Id)) then + if Present (Class_Preconditions (Subp_Id)) + -- Evaluate the expression if we are building a dynamic helper + -- or we are building a static helper for a non-abstract tagged + -- type; for abstract tagged types the helper just returns True + -- since it is called by the indirect call wrapper (ICW). + and then + (Is_Dynamic + or else + not Is_Abstract_Type (Find_Dispatching_Type (Subp_Id))) + then Return_Expr := Copy_And_Update_References (Class_Preconditions (Subp_Id)); @@ -3910,7 +3919,8 @@ package body Contracts is -- enabled. else - pragma Assert (Present (Ignored_Class_Preconditions (Subp_Id))); + pragma Assert (Present (Ignored_Class_Preconditions (Subp_Id)) + or else Is_Abstract_Type (Find_Dispatching_Type (Subp_Id))); Return_Expr := New_Occurrence_Of (Standard_True, Loc); end if;