DomainKey-Signature: a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id
	:list-unsubscribe:list-subscribe:list-archive:list-post
	:list-help:sender:to:from:subject:message-id:date:mime-version
	:content-type; q=dns; s=default; b=OwFGenXfxZgLSdP6ATvEyaf48Av2/
	J6XeZeiaUluDugV6GIdVLRESVHwuq2cVOLhvFjghXGWUAQEIZXZUjk4ZezV4+Cyt
	PI46damjCHx0dlOMAMVBMp9ZCaZLDIxf44aCB1K+6oiIbJvkUtQaVQp5YaoJ4c0B
	pbwjBcOLO2ub5c=
Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm
Sender: cygwin-owner AT cygwin DOT com
Mail-Followup-To: cygwin AT cygwin DOT com
To: cygwin AT cygwin DOT com
From: Michael Haubenwallner <michael DOT haubenwallner AT ssi-schaefer DOT com>
Subject: linker (binutils ld) is unable to resolve weak symbol, depends on object file order
Openpgp: preference=signencrypt
Message-ID: <c302ea94-ae7b-f7b1-9d8f-0c2e31dc6bc7@ssi-schaefer.com>
Date: Fri, 7 Jun 2019 12:04:43 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0
MIME-Version: 1.0
Content-Type: multipart/mixed; boundary="------------DE594A2A9434DC3CF1F20BD3"

--------------DE594A2A9434DC3CF1F20BD3
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit

Hi,

so I'm encountering a strange problem related to object file order passed to
the linker, with any binutils and gcc version available to setup-x86_64.exe:

$ cat weak-func.c
extern void weakfunc() __attribute__((weak));
void weakfunc() {}

$ cat weak-main.c
extern void weakfunc() __attribute__((weak));
int main() { weakfunc(); }

$ gcc -o weak.exe weak-func.c weak-main.c
SUCCESS

But then, changing the order of input files on the command line does break
(does work on Linux of course):

$ gcc -o weak.exe weak-main.c weak-func.c
/usr/lib/gcc/x86_64-pc-cygwin/8.3.0/../../../../x86_64-pc-cygwin/bin/ld: /tmp/ccIthYHe.o:weak-main.c:(.text+0xe): relocation truncated to fit: R_X86_64_PC32 against undefined symbol `weakfunc'
collect2: error: ld returned 1 exit status

So the difference is that the object providing weakfunc is passed to
the linker after the object requiring weakfunc.

Attached is the weak-func.sh script that does perform these commands.

Thanks!
/haubi/

--------------DE594A2A9434DC3CF1F20BD3
Content-Type: application/x-shellscript;
 name="weak-func.sh"
Content-Transfer-Encoding: base64
Content-Disposition: attachment;
 filename="weak-func.sh"
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--------------DE594A2A9434DC3CF1F20BD3
Content-Type: text/plain; charset=us-ascii


--
Problem reports:       http://cygwin.com/problems.html
FAQ:                   http://cygwin.com/faq/
Documentation:         http://cygwin.com/docs.html
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple
--------------DE594A2A9434DC3CF1F20BD3--