DMARC-Filter: OpenDMARC Filter v1.4.2 delorie.com 51BNsTms546507
Authentication-Results: delorie.com; dmarc=pass (p=none dis=none) header.from=cygwin.com
Authentication-Results: delorie.com; spf=pass smtp.mailfrom=cygwin.com
DKIM-Filter: OpenDKIM Filter v2.11.0 delorie.com 51BNsTms546507
Authentication-Results: delorie.com;
	dkim=pass (1024-bit key, unprotected) header.d=cygwin.com header.i=@cygwin.com header.a=rsa-sha256 header.s=default header.b=ZgNP5fyX
X-Recipient: archive-cygwin AT delorie DOT com
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 1371A3858416
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cygwin.com;
	s=default; t=1739318068;
	bh=Ekuv6oy4MSRMe2c6g3LxRpL1csQdEwxgqtwaHhIWgZ4=;
	h=Date:Subject:To:References:In-Reply-To:List-Id:List-Unsubscribe:
	 List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To:Cc:
	 From;
	b=ZgNP5fyXEFV+cIfC7K2cShG7qf75eBim7QDZY7UzemymDej1bGkE7rhr60Pg+PhUy
	 A6XnyveLN0p2qmnM6qd/vpRrxgn19ErIzjIMYJAzwrmPAKakro+3y8RkssKInbFJF0
	 qi5gdukoCAESNsxFDnKsCCJY011W/69/1Q2AEA/o=
X-Original-To: cygwin AT cygwin DOT com
Delivered-To: cygwin AT cygwin DOT com
DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 74ABB3858D39
ARC-Filter: OpenARC Filter v1.0.0 sourceware.org 74ABB3858D39
ARC-Seal: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1739318011; cv=none;
 b=QnbIIOWaTp1xrdJ6KiQtmfnl59BlpEnAfWTPQ0xIJ7WQks1f6FYjNYvZrcYfHrfaoVxoy1cnTh+xeRTyOSM0V5VFhlqp89bzLHZhSeXPm25+fvtS2ErlrEi7z3Zlg0PrMR+KtAIoSFnfZkZ/dvTlhrTjoX5hNayIac3PDSWwF6o=
ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key;
 t=1739318011; c=relaxed/simple;
 bh=EA3EQpvl+6WweHFvrvaq2nrCgj7V9ReRN6dHshFG8zo=;
 h=Message-ID:Date:MIME-Version:From:Subject:To:DKIM-Signature;
 b=m81l2nVerf59uDEEBW6NWtd+xSeAx0Ej8QFf5h4/zN6jEhWABlITfei/zDv8UfqgOyO3YJGInZq+4Pi3m4/ZsBztTr/Bbf5BW12KhPiEfNAr0Hgp+rPx6Jtf9kjSWvBm9oULk/6jPD31eKS4Q6JY7pSKosLS1dENfWCiBd+2FvI=
ARC-Authentication-Results: i=1; server2.sourceware.org
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 74ABB3858D39
Message-ID: <4eb423e0-cfbb-48d5-a8ed-5a255bd712a1@SystematicSW.ab.ca>
Date: Tue, 11 Feb 2025 16:53:28 -0700
MIME-Version: 1.0
User-Agent: Mozilla Thunderbird
Subject: Re: __builtin_thread_pointer
Content-Language: en-CA
To: The Cygwin Mailing List <cygwin AT cygwin DOT com>
References: <9c6a1ccc-d2fb-4aaf-b8c2-29574fa640b4 AT cornell DOT edu>
 <D47E777E-C732-47BD-81C8-5A488E38E1F3 AT unified-streaming DOT com>
 <6faedefc-eb17-4b02-89b9-44b73e82d43f AT SystematicSW DOT ab DOT ca>
 <0252F948-10C3-4B9E-943D-ACA35E190726 AT unified-streaming DOT com>
Autocrypt: addr=Brian DOT Inglis AT SystematicSW DOT ab DOT ca; keydata=
 xjMEXopx8xYJKwYBBAHaRw8BAQdAnCK0qv/xwUCCZQoA9BHRYpstERrspfT0NkUWQVuoePbN
 LkJyaWFuIEluZ2xpcyA8QnJpYW4uSW5nbGlzQFN5c3RlbWF0aWNTdy5hYi5jYT7ClgQTFggA
 PhYhBMM5/lbU970GBS2bZB62lxu92I8YBQJeinHzAhsDBQkJZgGABQsJCAcCBhUKCQgLAgQW
 AgMBAh4BAheAAAoJEB62lxu92I8Y0ioBAI8xrggNxziAVmr+Xm6nnyjoujMqWcq3oEhlYGAO
 WacZAQDFtdDx2koSVSoOmfaOyRTbIWSf9/Cjai29060fsmdsDM44BF6KcfMSCisGAQQBl1UB
 BQEBB0Awv8kHI2PaEgViDqzbnoe8B9KMHoBZLS92HdC7ZPh8HQMBCAfCfgQYFggAJhYhBMM5
 /lbU970GBS2bZB62lxu92I8YBQJeinHzAhsMBQkJZgGAAAoJEB62lxu92I8YZwUBAJw/74rF
 IyaSsGI7ewCdCy88Lce/kdwX7zGwid+f8NZ3AQC/ezTFFi5obXnyMxZJN464nPXiggtT9gN5
 RSyTY8X+AQ==
Organization: Systematic Software
In-Reply-To: <0252F948-10C3-4B9E-943D-ACA35E190726@unified-streaming.com>
X-Rspamd-Queue-Id: 64ECE20031
X-Stat-Signature: cd6qo3x3z55jrw851eswwm1uahz8qdd9
X-Rspamd-Server: rspamout03
X-Session-Marker: 427269616E2E496E676C69734053797374656D6174696353572E61622E6361
X-Session-ID: U2FsdGVkX1+cp3LjDPB2HcT3uzvfy/Y45vk7v7BSdUw=
X-HE-Tag: 1739318009-642280
X-HE-Meta: U2FsdGVkX18g41/eArJrVTVczFRsoTxp/pjCGc6mQwGNr4RqZADwuDXEOmdkI/fV8eddRk7xfoSgzEP6Zm86GgDzJTWAEG5fiJF85d0+WHucoOjsX6tcVTwjdS20pBUgkOepeMXFCqd5Qg1DnZDZmIaao5EJ7S3i2tV0Op+QrMJ2X9PQ1eabkWypWpR6acikOnrhk58n1PSuYmSnxjIGOibtJydJUjiXLd7ULdFf77iImYrqnPRU2H/saJHJLZA4cotcKO6TtRHpc/hVMUb71WzFs0ZFdLprnTiRgjhiEMCPPk8cUyIoGkyK0Qim54x1bag6UD/g3jfPtHw/QSMhzEJiabvvR//M
X-BeenThere: cygwin AT cygwin DOT com
X-Mailman-Version: 2.1.30
Precedence: list
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: Brian Inglis via Cygwin <cygwin AT cygwin DOT com>
Reply-To: cygwin AT cygwin DOT com
Cc: Brian Inglis <Brian DOT Inglis AT SystematicSW DOT ab DOT ca>
Content-Type: text/plain; charset="utf-8"; Format="flowed"
Errors-To: cygwin-bounces~archive-cygwin=delorie DOT com AT cygwin DOT com
Sender: "Cygwin" <cygwin-bounces~archive-cygwin=delorie DOT com AT cygwin DOT com>
Content-Transfer-Encoding: 8bit
X-MIME-Autoconverted: from base64 to 8bit by delorie.com id 51BNsTms546507

On 2025-02-11 13:58, Dimitry Andric wrote:
>> On 11 Feb 2025, at 21:45, Brian Inglis via Cygwin wrote:
>> On 2025-02-11 12:41, Dimitry Andric via Cygwin wrote:
>>>> On 11 Feb 2025, at 20:26, Ken Brown via Cygwin wrote:
>>>> Does Cygwin support __builtin_thread_pointer?  I'm guessing not, because
>>>> I'm getting a link error (undefined reference to
>>>> `__builtin_thread_pointer') when I try to build some software that uses
>>>> it.  Or is there something that would have to be added to the link command
>>>> line?  The full command line and error message are quoted below, in case
>>>> anyone spots something obvious.
>>
>>> It's a gcc builtin function, not something implemented in an external library. Therefore, there is no linker option that can fix this.
>>> Also, as far as I can see from gcc's documentation,
>>> __builtin_thread_pointer() is only supported for the RISCV and SH
>>> architectures. Then again, gcc's implementation seems to hinge this on
>>> whether the platform supports TLS or not.
>>> In any case, it is probably better to not use this function if your gcc does
>>> not support it.
>> Does `info gcc tls` help and do we know if that is supported by our gcc(s)?

 > It does not look like it's supported by Cygwin's gcc:
 >
 > $ gcc -v
 > Using built-in specs.
 > COLLECT_GCC=gcc
 > COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-pc-cygwin/12/lto-wrapper.exe
 > Target: x86_64-pc-cygwin
 > Configured with: /mnt/share/cygpkgs/gcc/gcc.x86_64/src/gcc-12.4.0/configure 
--srcdir=/mnt/share/cygpkgs/gcc/gcc.x86_64/src/gcc-12.4.0 --prefix=/usr 
--exec-prefix=/usr --localstatedir=/var --sysconfdir=/etc 
--docdir=/usr/share/doc/gcc --htmldir=/usr/share/doc/gcc/html -C 
--build=x86_64-pc-cygwin --host=x86_64-pc-cygwin --target=x86_64-pc-cygwin 
--without-libiconv-prefix --without-libintl-prefix --libexecdir=/usr/lib 
--with-gcc-major-version-only --enable-shared --enable-shared-libgcc 
--enable-static --enable-version-specific-runtime-libs --enable-bootstrap 
--enable-__cxa_atexit --enable-clocale=newlib --with-dwarf2 --with-tune=generic 
--enable-languages=ada,c,c++,fortran,lto,objc,obj-c++,jit --enable-graphite 
--enable-threads=posix --enable-libatomic --enable-libgomp --enable-libquadmath 
--enable-libquadmath-support --disable-libssp --enable-libada --disable-symvers 
--disable-multilib --with-gnu-ld --with-gnu-as 
--with-cloog-include=/usr/include/cloog-isl --without-libiconv-prefix 
--without-libintl-prefix --with-system-zlib --enable-linker-build-id 
--with-default-libstdcxx-abi=gcc4-compatible --enable-libstdcxx-filesystem-ts
 > Thread model: posix
 > Supported LTO compression algorithms: zlib zstd
 > gcc version 12.4.0 (GCC)
 >
 > $ cat test-builtin-thread-pointer.c
 > void f(void)
 > {
 >    void *p = __builtin_thread_pointer();
 > }

If you read the docs at `info gcc tls` it uses the __thread storage class to 
allow you to declare auto, extern, or static thread variables like any other.

Whether that would run as expected is more than I can deduce.

-- 
Take care. Thanks, Brian Inglis              Calgary, Alberta, Canada

La perfection est atteinte                   Perfection is achieved
non pas lorsqu'il n'y a plus rien à ajouter  not when there is no more to add
mais lorsqu'il n'y a plus rien à retrancher  but when there is no more to cut
                                 -- Antoine de Saint-Exupéry

-- 
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