From: Piotr Trojanek <trojanek@adacore.com>
Date: Thu, 31 Mar 2022 18:56:58 +0000 (+0200)
Subject: [Ada] Prevent overflow in computation of aggregate size
X-Git-Tag: basepoints/gcc-14~6617
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=16b8ba101f770503f363c095d7be5c055705b84b;p=thirdparty%2Fgcc.git

[Ada] Prevent overflow in computation of aggregate size

When computing size of a static aggregate to decide if it should be
transformed into assignments and loops we could have an overflow check.
This is mostly harmless, because colossal aggregates will likely crash
the application anyway, no matter how we transform them.

This was not detected because compiler was built with -gnatg switch that
suppresses overflow checks (they are only enabled by an explicit -gnato
switch).

gcc/ada/

	* exp_aggr.adb (Component_Count): Calculate size as an Uint and
	only then check if it is in the range of Int, as otherwise the
	multiplication of Int values can overflow.
---

diff --git a/gcc/ada/exp_aggr.adb b/gcc/ada/exp_aggr.adb
index 72f65555681..4714cab8bfa 100644
--- a/gcc/ada/exp_aggr.adb
+++ b/gcc/ada/exp_aggr.adb
@@ -661,10 +661,10 @@ package body Exp_Aggr is
 
                   declare
                      UI : constant Uint :=
-                            Expr_Value (Hi) - Expr_Value (Lo) + 1;
+                            (Expr_Value (Hi) - Expr_Value (Lo) + 1) * Siz;
                   begin
                      if UI_Is_In_Int_Range (UI) then
-                        return Siz * UI_To_Int (UI);
+                        return UI_To_Int (UI);
                      else
                         return Int'Last;
                      end if;