X-Recipient:	archive-cygwin AT delorie DOT com
DKIM-Filter:	OpenDKIM Filter v2.11.0 sourceware.org 1C745385C8B1
DKIM-Signature:	v=1; a=rsa-sha256; c=relaxed/relaxed; d=cygwin.com;
	s=default; t=1597697414;
	bh=BfW4Fc14BTUdcmcz5u2JVJGi7xETqa3h/3FwrN0+Vhc=;
	h=Subject:To:References:Date:In-Reply-To:List-Id:List-Unsubscribe:
	List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To:Cc:
	From;
	b=NVHbe3HaDSfApCgCLjNWPNFAjv2uo2MGWbsDFZobuKHrrvPpZUV3ydaEtY6bBdX4p
	jyahpYQGqmq0vi9VvOxnw4ynSLmiwKgqF2J++s/eu7CzBooZLKhjQc7VWC+MyRIB31
	pzw0cEjdx2jRy2Al8/JrOptV+av6u5ms6V58Rayg=
X-Original-To:	cygwin AT cygwin DOT com
Delivered-To:	cygwin AT cygwin DOT com
DMARC-Filter:	OpenDMARC Filter v1.3.2 sourceware.org AC50F3857C43
ARC-Seal:	i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none;
	b=AYkF+DiEvZjSy0JdJJiCEqj5+OJBMl3a4Xz18wLNAj+L/Q8pS4ttML+Nr47hYGN8zSuR7MjzIuWGbTYVI/xsb0yYVITQelrdpM/Y1xFUGNuCEtWLsPugh5IQCk/mlogVGq1mkwCcfrhPuS0S++KAW/kyexImj5Cd5ATr1mZ3mTbxa5MDcKEGavE4qy+qFEVIkVxCC5MDS1ra+t4jyzErkCX2lBFyPoiQjI8bU2qxpm2MsN381HEFs7jALJyOCVnC9W8opFu/3z3THHdwT0KjCjAzzRBrPZwruxWEsr555dXTMQLzELmLQKCbQvsYFakoPJlvu5OIAvRsoPXAEAKLEg==
ARC-Message-Signature:	i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com;
	s=arcselector9901;
	h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck;
	bh=yfA/Bl060xIxQYe7grEIkmRQ7FVTLWqlxuPBW8KV70g=;
	b=Kv4MQLV+92NzFLsYoYyGwbIAfTOp7kxRjU8F2MN0OKDDAfSXs1zsDvtLjEjDfyQFw5hnI6H7YvDZpUewHVnkpO/95sZRGOxXOIzGUGQvLGIB1+6AjVH5Gmp4PKCUh6rm5ZQBL9p213reTkG8MKLYIcktvbtfeMqeSGqU5RdC3AFWEovQQDNMUVydZvHq+28EBer2+oQbZ9wQLfES/UM4Gmp4yfVK+GHoGHPsFGUiEfvCrUHKZPTK4S04yE/C7yIrOp/Exx975NzTwDH6Gt0fp9uI4u4Vw3Yp0JG2Y4JnVYPEC9u1v8kEEAc6tTicdLFyNu7iCKqcxXeIMmYQYZ4cxA==
ARC-Authentication-Results:	i=1; mx.microsoft.com 1; spf=pass
	smtp.mailfrom=cornell.edu; dmarc=pass action=none header.from=cornell.edu;
	dkim=pass header.d=cornell.edu; arc=none
Subject:	Re: [Attn: gcc maintainers] Re: unhandled C++ exceptions not
	propagating
To:	cygwin AT cygwin DOT com
References:	<vritk0xzfpk6 DOT fsf AT gmail DOT com>
	<20200816125306 DOT 60dc246baf63d7f9fba60611 AT nifty DOT ne DOT jp>
	<6c27d8d6-876a-6c09-bccd-a9123400cfdb AT cornell DOT edu>
	<20200816225221 DOT d7c41334927c9766d6e26415 AT nifty DOT ne DOT jp>
	<84a15cee-d772-4422-9cf0-1cec8d188cae AT cornell DOT edu>
	<70f23307-6aaf-db8a-103e-81303350ffec AT cornell DOT edu>
	<9525d8c2-74af-5c04-8a04-d84df4b1f2ef AT cornell DOT edu>
	<20200817181359 DOT GI3272 AT calimero DOT vinschen DOT de>
	<8338a995-1bab-9489-55c2-b6eb2e0ac844 AT cornell DOT edu>
	<437eecde-22ea-2777-3062-a0f43e7dbc70 AT cornell DOT edu>
Message-ID:	<27077c89-c826-2e5d-fcbe-1aa64fca4690@cornell.edu>
Date:	Mon, 17 Aug 2020 16:50:03 -0400
User-Agent:	Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101
	Thunderbird/68.11.0
In-Reply-To:	<437eecde-22ea-2777-3062-a0f43e7dbc70@cornell.edu>
X-ClientProxiedBy:	BL0PR0102CA0072.prod.exchangelabs.com
	(2603:10b6:208:25::49) To MN2PR04MB6176.namprd04.prod.outlook.com
	(2603:10b6:208:e3::13)
MIME-Version:	1.0
X-MS-Exchange-MessageSentRepresentingType:	1
X-Originating-IP:	[2604:6000:b407:7f00:6ddb:1b9b:deef:3580]
X-MS-PublicTrafficType:	Email
X-MS-Office365-Filtering-Correlation-Id:	ad272ebf-0808-4396-3381-08d842ef1ea0
X-MS-TrafficTypeDiagnostic:	MN2PR04MB6223:
X-Microsoft-Antispam-PRVS:	<MN2PR04MB62237DA466006413AB6BB13DD85F0 AT MN2PR04MB6223 DOT namprd04 DOT prod DOT outlook DOT com>
X-MS-Oob-TLC-OOBClassifiers:	OLM:9508;
X-MS-Exchange-SenderADCheck:	1
X-Microsoft-Antispam:	BCL:0;
X-Microsoft-Antispam-Message-Info:	rZjt7EqQ72jAZBKzHqtbngXvcaMFXTWWXoY0zDPuYeNxmJlJaqK8U64V0B6M1o6K5PPCodkh7PzfgBbw3qEi5ijhgqnlDk8FmEGDUh6Buo+EZgE24JywjM44359GVGip+n88YhEIaBFI5kahIIhF7ifFZbFq+5Vvf7pv7WNmtj1lhuPauGj5xZaoizs/eNrvPKBvBqZEzdcRXzTyJ6fcfYI2wpeNo7v2wLnNQgnwa+i9G9Ro50A6Unk8qnYx9BhqkC1ereRPgcbt47pCn3/7nIjYjjqbk9hKFGtgtoySDUp3wGApT6bC8thJQnQPUlyuhk0B6B5Nc8xRKcXt6095CNwFvz1Dj0XOU3jaGUm+RzKYBdzrrt+GmBAWM16eZlFA
X-Forefront-Antispam-Report:	CIP:255.255.255.255; CTRY:; LANG:en; SCL:1; SRV:;
	IPV:NLI; SFV:NSPM; H:MN2PR04MB6176.namprd04.prod.outlook.com; PTR:; CAT:NONE;
	SFS:(4636009)(366004)(39860400002)(346002)(376002)(136003)(396003)(31686004)(66476007)(8676002)(316002)(16526019)(31696002)(66556008)(6486002)(86362001)(6916009)(786003)(66946007)(53546011)(75432002)(36756003)(2616005)(5660300002)(186003)(2906002)(8936002)(478600001)(4326008)(52116002)(43740500002);
	DIR:OUT; SFP:1102;
X-MS-Exchange-AntiSpam-MessageData:	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
X-OriginatorOrg:	cornell.edu
X-MS-Exchange-CrossTenant-Network-Message-Id:	ad272ebf-0808-4396-3381-08d842ef1ea0
X-MS-Exchange-CrossTenant-AuthSource:	MN2PR04MB6176.namprd04.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs:	Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime:	17 Aug 2020 20:50:05.2307 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader:	Hosted
X-MS-Exchange-CrossTenant-Id:	5d7e4366-1b9b-45cf-8e79-b14b27df46e1
X-MS-Exchange-CrossTenant-MailboxType:	HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName:	Fsbja9d0avtLA03FGr9teNt81a7M0Ce++KWCD2B0gtWv7qmrfS2Yczd04s9WcSch8tQZxAN2QW1/tuZYpAZFfw==
X-MS-Exchange-Transport-CrossTenantHeadersStamped:	MN2PR04MB6223
X-Spam-Status:	No, score=-1.0 required=5.0 tests=BAYES_00, DKIM_INVALID,
	DKIM_SIGNED, KAM_DMARC_STATUS, MSGID_FROM_MTA_HEADER, NICE_REPLY_A,
	RCVD_IN_MSPIKE_H2, SPF_HELO_PASS, SPF_PASS,
	TXREP autolearn=no autolearn_force=no version=3.4.2
X-Spam-Checker-Version:	SpamAssassin 3.4.2 (2018-09-13) on
	server2.sourceware.org
X-BeenThere:	cygwin AT cygwin DOT com
X-Mailman-Version:	2.1.29
List-Id:	General Cygwin discussions and problem reports <cygwin.cygwin.com>
List-Unsubscribe:	<https://cygwin.com/mailman/options/cygwin>,
	<mailto:cygwin-request AT cygwin DOT com?subject=unsubscribe>
List-Archive:	<https://cygwin.com/pipermail/cygwin/>
List-Post:	<mailto:cygwin AT cygwin DOT com>
List-Help:	<mailto:cygwin-request AT cygwin DOT com?subject=help>
List-Subscribe:	<https://cygwin.com/mailman/listinfo/cygwin>,
	<mailto:cygwin-request AT cygwin DOT com?subject=subscribe>
From:	Ken Brown via Cygwin <cygwin AT cygwin DOT com>
Reply-To:	Ken Brown <kbrown AT cornell DOT edu>
Cc:	David McFarland <corngood AT gmail DOT com>
Errors-To:	cygwin-bounces AT cygwin DOT com
Sender:	"Cygwin" <cygwin-bounces AT cygwin DOT com>
X-MIME-Autoconverted:	from quoted-printable to 8bit by delorie.com id 07HKodKD008420

On 8/17/2020 4:40 PM, Ken Brown via Cygwin wrote:
> On 8/17/2020 3:06 PM, Ken Brown via Cygwin wrote:
>> On 8/17/2020 2:13 PM, Corinna Vinschen wrote:
>>> On Aug 17 13:36, Ken Brown via Cygwin wrote:
>>>> On 8/16/2020 6:38 PM, Ken Brown via Cygwin wrote:
>>>>> One further comment, and then I'll shut up
>>>>
>>>> I lied.
>>>
>>> ...which is ok.
>>>
>>>>> and leave it to people who know what they're talking about: In the
>>>>> 64-bit case, the function _Unwind_RaiseException in libgcc/unwind-seh.c
>>>>> gets called, and it calls the Win32 function RaiseException as follows:
>>>>>
>>>>>     RaiseException (STATUS_GCC_THROW, 0, 1, (ULONG_PTR *)&exc);
>>>>>
>>>>> Then the following comment appears:
>>>>>
>>>>>     /* The exception handler installed in crt0 will continue any GCC
>>>>>        exception that reaches there (and isn't marked non-continuable).
>>>>>        Returning allows the C++ runtime to call std::terminate.  */
>>>>>
>>>>> Apparently this doesn't actually happen.
>>>>
>>>> I'm beginning to think this is a bug in the Cygwin build of gcc.  The file
>>>> unwind-seh.c is compiled on 64-bit Cygwin because __SEH__ is defined.  But
>>>> it makes assumptions, such as those in the comment quoted above, that are
>>>> not valid on Cygwin.
>>>>
>>>> In fact, if you look at the main exception handler on Cygwin
>>>> (exceptions.cc:626), it is clear that the exception code STATUS_GCC_THROW
>>>> does not lead to continuation.  It falls under the default case:
>>>>
>>>>      default:
>>>>        /* If we don't recognize the exception, we have to assume that
>>>>      we are doing structured exception handling, and we let
>>>>      something else handle it.  */
>>>>        return ExceptionContinueSearch;
>>>>
>>>> [STATUS_GCC_THROW is 0x20474343, which shows up in the gdb output above as
>>>> an unknown target exception.]
>>>>
>>>> So it seems to me that either Cygwin's exception handler has to learn to
>>>> handle the exception codes defined in unwind-seh.c, or else gcc should be
>>>> built with __SEH__ undefined.
>>>>
>>>> JonY, Achim, Corinna, am I missing something?
>>>
>>> This stuff isn't really my strong point.  IIUC the above comment correctly,
>>> we might get away with adding another case to the exception handler switch:
>>>
>>>    #define STATUS_GCC_THROW 0x20474343
>>>    case STATUS_GCC_THROW:
>>>      return ExceptionContinueExecution;
>>>
>>> Did you try that, by any chance?
>>
>> No, I didn't.  It might well solve the immediate problem of this bug report. 
>> But then there are two other exception codes that occur in unwind-seh.c that 
>> we would also have to deal with: STATUS_GCC_UNWIND    and STATUS_GCC_FORCED. 
>> Someone would have to look at their uses and figure out what, if anything, 
>> Cygwin should do with them.
> 
> This isn't an issue after all.  The comment I quoted above refers to all GCC 
> exceptions, not just STATUS_GCC_THROW.  I'll submit a patch after testing.

I've sent the patch.  The output of the OP's test case is now the same on 64-bit 
as on 32-bit:

$ ./a
terminate called after throwing an instance of 'std::logic_error'
   what():  basic_string::_S_construct null not valid
Aborted (core dumped)

Ken
--
Problem reports:      https://cygwin.com/problems.html
FAQ:                  https://cygwin.com/faq/
Documentation:        https://cygwin.com/docs.html
Unsubscribe info:     https://cygwin.com/ml/#unsubscribe-simple

- Raw text -