From patchwork Fri Sep 8 10:08:33 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Arnaud Charlet X-Patchwork-Id: 811460 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=gcc.gnu.org (client-ip=209.132.180.131; helo=sourceware.org; envelope-from=gcc-patches-return-461716-incoming=patchwork.ozlabs.org@gcc.gnu.org; receiver=) Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=gcc.gnu.org header.i=@gcc.gnu.org header.b="Y77zKbLx"; dkim-atps=neutral Received: from sourceware.org (server1.sourceware.org [209.132.180.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3xpY1r221rz9rxj for ; Fri, 8 Sep 2017 20:08:47 +1000 (AEST) DomainKey-Signature: a=rsa-sha1; c=nofws; d=gcc.gnu.org; h=list-id :list-unsubscribe:list-archive:list-post:list-help:sender:date :from:to:cc:subject:message-id:mime-version:content-type; q=dns; s=default; b=HYKERBnrO/mZlyszaI2xJ65e047v2KH1S2TBucEC8eFvOanYcF JGScC6erL3rn0Z6HqAp5v86EekZPCcK3kzde22GPNgdYHmYo7xB75eMcGLh/TK5Y CV4kwKh12nOcn5mQAxY4r+x36U8x7VsFPGWjgmkC8Myr6pkBhi5KO90nc= DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=gcc.gnu.org; h=list-id :list-unsubscribe:list-archive:list-post:list-help:sender:date :from:to:cc:subject:message-id:mime-version:content-type; s= default; bh=NPMOYxYgbkhPZtQO1QU58O3vgAY=; b=Y77zKbLx56SvDjiY8oUM sTJvUa/kYxe3R8y1YXk4N/XYgRyXj1blJmIuyi3vtRs5oW67CaVZqHeBxrfxffUb y7fqQEhBRxgKQtKoTtUGLEtUMgZDfgMA46c8ErytKzZL3wL28u07LnJp6s5HHfAb bF7ueUPPVOgo1kDerpxAVms= Received: (qmail 130572 invoked by alias); 8 Sep 2017 10:08:40 -0000 Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Archive: List-Post: List-Help: Sender: gcc-patches-owner@gcc.gnu.org Delivered-To: mailing list gcc-patches@gcc.gnu.org Received: (qmail 130149 invoked by uid 89); 8 Sep 2017 10:08:39 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-11.9 required=5.0 tests=BAYES_00, GIT_PATCH_2, GIT_PATCH_3, RCVD_IN_DNSWL_NONE, SPF_PASS autolearn=ham version=3.3.2 spammy=Hx-languages-length:2160 X-HELO: rock.gnat.com Received: from rock.gnat.com (HELO rock.gnat.com) (205.232.38.15) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Fri, 08 Sep 2017 10:08:34 +0000 Received: from localhost (localhost.localdomain [127.0.0.1]) by filtered-rock.gnat.com (Postfix) with ESMTP id 4ACFB5619D; Fri, 8 Sep 2017 06:08:33 -0400 (EDT) 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 XSnb2knnk6xv; Fri, 8 Sep 2017 06:08:33 -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 370AB56126; Fri, 8 Sep 2017 06:08:33 -0400 (EDT) Received: by tron.gnat.com (Postfix, from userid 4192) id 33816505; Fri, 8 Sep 2017 06:08:33 -0400 (EDT) Date: Fri, 8 Sep 2017 06:08:33 -0400 From: Arnaud Charlet To: gcc-patches@gcc.gnu.org Cc: Hristian Kirtchev Subject: [Ada] Infinite loop on call to nested subprogram with -gnatE in SPARK Message-ID: <20170908100833.GA138716@adacore.com> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.5.23 (2014-03-12) This patch suppresses the processing of references to internal variables for SPARK. As a result, this eliminates an infinite loop triggered by walking the scope chain of an internal variable which plays the role of an elaboration flag. ------------ -- Source -- ------------ -- gnat.adc pragma SPARK_Mode (On); -- pack1.ads package Pack1 is procedure Proc; end Pack1; -- pack1.adb package body Pack1 is procedure Proc is begin null; end Proc; end Pack1; -- pack2.ads package Pack2 is procedure Proc; end Pack2; -- pack2.adb with Pack1; package body Pack2 is procedure Proc is procedure Nested_Proc is begin Pack1.Proc; end Nested_Proc; begin Nested_Proc; end Proc; end Pack2; -- main.adb with Pack2; procedure Main is begin null; end Main; ----------------- -- Compilation -- ----------------- $ gnatmake -q -gnatE main.adb Tested on x86_64-pc-linux-gnu, committed on trunk 2017-09-08 Hristian Kirtchev * sem_elab.adb (Check_A_Call): Do not consider references to internal variables for SPARK semantics. Index: sem_elab.adb =================================================================== --- sem_elab.adb (revision 251863) +++ sem_elab.adb (working copy) @@ -721,23 +721,26 @@ and then not Is_Call_Of_Generic_Formal (N) then return; - end if; -- If this is a rewrite of a Valid_Scalars attribute, then nothing to -- check, we don't mind in this case if the call occurs before the body -- since this is all generated code. - if Nkind (Original_Node (N)) = N_Attribute_Reference + elsif Nkind (Original_Node (N)) = N_Attribute_Reference and then Attribute_Name (Original_Node (N)) = Name_Valid_Scalars then return; - end if; -- Intrinsics such as instances of Unchecked_Deallocation do not have -- any body, so elaboration checking is not needed, and would be wrong. - if Is_Intrinsic_Subprogram (E) then + elsif Is_Intrinsic_Subprogram (E) then return; + + -- Do not consider references to internal variables for SPARK semantics + + elsif Variable_Case and then not Comes_From_Source (E) then + return; end if; -- Proceed with check