* [COMMITTED] ada: Tune handling of attributes Old in contract Exceptional_Cases
@ 2023-05-25 8:05 Marc Poulhiès
0 siblings, 0 replies; only message in thread
From: Marc Poulhiès @ 2023-05-25 8:05 UTC (permalink / raw)
To: gcc-patches; +Cc: Piotr Trojanek
From: Piotr Trojanek <trojanek@adacore.com>
Contract Exceptional_Cases allows formal parameters to appear *in*
prefixes of attributes Old, but the code only allowed them to appear
*as* prefixes of those attributes.
For example, we now accetp expressions like "X.all'Old" that were
previously rejected.
gcc/ada/
* sem_res.adb (Resolve_Entity_Name): Tune handling of formal parameters
in contract Exceptional_Cases.
Tested on x86_64-pc-linux-gnu, committed on master.
---
gcc/ada/sem_res.adb | 32 ++++++++++++++++++++++++++++++--
1 file changed, 30 insertions(+), 2 deletions(-)
diff --git a/gcc/ada/sem_res.adb b/gcc/ada/sem_res.adb
index 17228689364..9161218a32b 100644
--- a/gcc/ada/sem_res.adb
+++ b/gcc/ada/sem_res.adb
@@ -7832,6 +7832,9 @@ package body Sem_Res is
-- Determine whether Expr is part of an N_Attribute_Reference
-- expression.
+ function In_Attribute_Old (Expr : Node_Id) return Boolean;
+ -- Determine whether Expr is in attribute Old
+
function Within_Exceptional_Cases_Consequence
(Expr : Node_Id)
return Boolean;
@@ -7878,6 +7881,31 @@ package body Sem_Res is
end if;
end Is_Assignment_Or_Object_Expression;
+ ----------------------
+ -- In_Attribute_Old --
+ ----------------------
+
+ function In_Attribute_Old (Expr : Node_Id) return Boolean is
+ N : Node_Id := Expr;
+ begin
+ while Present (N) loop
+ if Nkind (N) = N_Attribute_Reference
+ and then Attribute_Name (N) = Name_Old
+ then
+ return True;
+
+ -- Prevent the search from going too far
+
+ elsif Is_Body_Or_Package_Declaration (N) then
+ return False;
+ end if;
+
+ N := Parent (N);
+ end loop;
+
+ return False;
+ end In_Attribute_Old;
+
-----------------------------
-- Is_Attribute_Expression --
-----------------------------
@@ -8080,12 +8108,12 @@ package body Sem_Res is
-- Parameters of modes OUT or IN OUT of the subprogram shall not
-- occur in the consequences of an exceptional contract unless
- -- they either are of a by-reference type or occur in the prefix
+ -- they are either passed by reference or occur in the prefix
-- of a reference to the 'Old attribute.
if Ekind (E) in E_Out_Parameter | E_In_Out_Parameter
and then Within_Exceptional_Cases_Consequence (N)
- and then not Is_Attribute_Old (Parent (N))
+ and then not In_Attribute_Old (N)
and then not Is_By_Reference_Type (Etype (E))
and then not Is_Aliased (E)
then
--
2.40.0
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