From patchwork Thu May 6 07:58:12 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pierre-Marie de Rodat X-Patchwork-Id: 1474839 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=gcc.gnu.org (client-ip=8.43.85.97; helo=sourceware.org; envelope-from=gcc-patches-bounces@gcc.gnu.org; receiver=) Received: from sourceware.org (ip-8-43-85-97.sourceware.org [8.43.85.97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 4FbQtn01N6z9sRf for ; Thu, 6 May 2021 17:58:24 +1000 (AEST) Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 3119D3A5301D; Thu, 6 May 2021 07:58:15 +0000 (GMT) X-Original-To: gcc-patches@gcc.gnu.org Delivered-To: gcc-patches@gcc.gnu.org Received: from rock.gnat.com (rock.gnat.com [205.232.38.15]) by sourceware.org (Postfix) with ESMTP id 6F553383B415 for ; Thu, 6 May 2021 07:58:12 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 6F553383B415 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=adacore.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=derodat@adacore.com Received: from localhost (localhost.localdomain [127.0.0.1]) by filtered-rock.gnat.com (Postfix) with ESMTP id 25CB7562B5; Thu, 6 May 2021 03:58:12 -0400 (EDT) X-Virus-Scanned: Debian amavisd-new at gnat.com Received: from rock.gnat.com ([127.0.0.1]) by localhost (rock.gnat.com [127.0.0.1]) (amavisd-new, port 10024) with LMTP id v208QyTmp5Ns; Thu, 6 May 2021 03:58:12 -0400 (EDT) Received: from tron.gnat.com (tron.gnat.com [IPv6:2620:20:4000:0:46a8:42ff:fe0e:e294]) by rock.gnat.com (Postfix) with ESMTP id 123C1562B2; Thu, 6 May 2021 03:58:12 -0400 (EDT) Received: by tron.gnat.com (Postfix, from userid 4862) id 0B9511A1; Thu, 6 May 2021 03:58:12 -0400 (EDT) Date: Thu, 6 May 2021 03:58:12 -0400 From: Pierre-Marie de Rodat To: gcc-patches@gcc.gnu.org Subject: [Ada] Crash on if_expression used as index of discriminant-dependent array Message-ID: <20210506075811.GA125485@adacore.com> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.5.23 (2014-03-12) X-Spam-Status: No, score=-12.4 required=5.0 tests=BAYES_00, GIT_PATCH_0, KAM_DMARC_STATUS, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: gcc-patches@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Ed Schonberg Errors-To: gcc-patches-bounces@gcc.gnu.org Sender: "Gcc-patches" The compiler aborts on an if_expression used as an index when the object being indexed is a discriminant-dependent component, and the frontend generates an improper range check on the expression instead of the required index check. Tested on x86_64-pc-linux-gnu, committed on trunk gcc/ada/ * sem_res.adb (Resolve_If_Expression): If the context of the expression is an indexed_component, resolve the expression and its dependent_expressions with the base type of the index, to ensure that an index check is generated when resolving the enclosing indexxed_component, and avoid an improper use of discriminants out of scope, when the index type is discriminant-dependent. diff --git a/gcc/ada/sem_res.adb b/gcc/ada/sem_res.adb --- a/gcc/ada/sem_res.adb +++ b/gcc/ada/sem_res.adb @@ -9095,6 +9095,16 @@ package body Sem_Res is -- that the context in general allows sliding, while a qualified -- expression forces equality of bounds. + Result_Type : Entity_Id := Typ; + -- So in most cases the type of the If_Expression and of its + -- dependent expressions is that of the context. However, if + -- the expression is the index of an Indexed_Component, we must + -- ensure that a proper index check is applied, rather than a + -- range check on the index type (which might be discriminant + -- dependent). In this case we resolve with the base type of the + -- index type, and the index check is generated in the resolution + -- of the indexed_component above. + ----------------- -- Apply_Check -- ----------------- @@ -9118,10 +9128,10 @@ package body Sem_Res is else Rewrite (Expr, Make_Qualified_Expression (Loc, - Subtype_Mark => New_Occurrence_Of (Typ, Loc), + Subtype_Mark => New_Occurrence_Of (Result_Type, Loc), Expression => Relocate_Node (Expr))); - Analyze_And_Resolve (Expr, Typ); + Analyze_And_Resolve (Expr, Result_Type); end if; end Apply_Check; @@ -9140,6 +9150,12 @@ package body Sem_Res is return; end if; + if Nkind (Parent (N)) = N_Indexed_Component + or else Nkind (Parent (Parent (N))) = N_Indexed_Component + then + Result_Type := Base_Type (Typ); + end if; + Then_Expr := Next (Condition); if No (Then_Expr) then @@ -9149,7 +9165,7 @@ package body Sem_Res is Else_Expr := Next (Then_Expr); Resolve (Condition, Any_Boolean); - Resolve (Then_Expr, Typ); + Resolve (Then_Expr, Result_Type); Apply_Check (Then_Expr); -- If ELSE expression present, just resolve using the determined type @@ -9163,7 +9179,7 @@ package body Sem_Res is Resolve (Else_Expr, Any_Real); else - Resolve (Else_Expr, Typ); + Resolve (Else_Expr, Result_Type); end if; Apply_Check (Else_Expr); @@ -9187,7 +9203,7 @@ package body Sem_Res is elsif Root_Type (Typ) = Standard_Boolean then Else_Expr := Convert_To (Typ, New_Occurrence_Of (Standard_True, Sloc (N))); - Analyze_And_Resolve (Else_Expr, Typ); + Analyze_And_Resolve (Else_Expr, Result_Type); Append_To (Expressions (N), Else_Expr); else @@ -9195,7 +9211,7 @@ package body Sem_Res is Append_To (Expressions (N), Error); end if; - Set_Etype (N, Typ); + Set_Etype (N, Result_Type); if not Error_Posted (N) then Eval_If_Expression (N);