From c32983082576e1452a19bc7df8901d6e6d9229c2 Mon Sep 17 00:00:00 2001 From: Piotr Trojanek Date: Tue, 18 Jan 2022 23:04:12 +0100 Subject: [PATCH] [Ada] Raise Constraint_Error when converting negative values to Char_Code GNATprove relies on the comment for Get_Enum_Lit_From_Pos, which promises to raise Constraint_Error when its Pos parameter is not among the representation values for enumeration literal. However, this promise was only respected in builds with range checks enabled. The root problem was that a similar comment for conversion from Uint to Char_Code was likewise only respected in builds with range checks enabled. Now both routines respect promises in their comments. The behaviour of GNAT itself is not affected. The fix is needed to filter garbage counterexamples generated by provers for characters objects in SPARK. gcc/ada/ * uintp.adb (UI_To_CC): Guard against illegal inputs; reuse UI_To_Int. --- gcc/ada/uintp.adb | 29 ++++++++--------------------- 1 file changed, 8 insertions(+), 21 deletions(-) diff --git a/gcc/ada/uintp.adb b/gcc/ada/uintp.adb index 854d2e167b0..921c1d27956 100644 --- a/gcc/ada/uintp.adb +++ b/gcc/ada/uintp.adb @@ -2233,30 +2233,17 @@ package body Uintp is function UI_To_CC (Input : Valid_Uint) return Char_Code is begin - if Direct (Input) then - return Char_Code (Direct_Val (Input)); + -- Char_Code and Int have equal upper bounds, so simply guard against + -- negative Input and reuse conversion to Int. We trust that conversion + -- to Int will raise Constraint_Error when Input is too large. - -- Case of input is more than one digit + pragma Assert + (Char_Code'First = 0 and then Int (Char_Code'Last) = Int'Last); + if Input >= Uint_0 then + return Char_Code (UI_To_Int (Input)); else - declare - In_Length : constant Int := N_Digits (Input); - In_Vec : UI_Vector (1 .. In_Length); - Ret_CC : Char_Code; - - begin - Init_Operand (Input, In_Vec); - - -- We assume value is positive - - Ret_CC := 0; - for Idx in In_Vec'Range loop - Ret_CC := Ret_CC * Char_Code (Base) + - Char_Code (abs In_Vec (Idx)); - end loop; - - return Ret_CC; - end; + raise Constraint_Error; end if; end UI_To_CC;