X-Recipient:	archive-cygwin AT delorie DOT com
X-SWARE-Spam-Status:	No, hits=-2.5 required=5.0 tests=AWL,BAYES_00,SPF_PASS
X-Spam-Check-By:	sourceware.org
Message-ID:	<4AF0E721.8000102@users.sourceforge.net>
Date:	Tue, 03 Nov 2009 20:29:53 -0600
From:	"Yaakov (Cygwin/X)" <yselkowitz AT users DOT sourceforge DOT net>
User-Agent:	Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.1.4pre) Gecko/20090915 Thunderbird/3.0b4
MIME-Version:	1.0
To:	cygwin AT cygwin DOT com
Subject:	binutils: dlltool DATA exports incompatible with auto-import
Mailing-List:	contact cygwin-help AT cygwin DOT com; run by ezmlm
List-Id:	<cygwin.cygwin.com>
List-Subscribe:	<mailto:cygwin-subscribe AT cygwin DOT com>
List-Archive:	<http://sourceware.org/ml/cygwin/>
List-Post:	<mailto:cygwin AT cygwin DOT com>
List-Help:	<mailto:cygwin-help AT cygwin DOT com>, <http://sourceware.org/ml/#faqs>
Sender:	cygwin-owner AT cygwin DOT com
Mail-Followup-To:	cygwin AT cygwin DOT com
Delivered-To:	mailing list cygwin AT cygwin DOT com

--------------050201050905050707060801
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit

GNOME Evolution contains several interdependent libraries, so on 
Cygwin/MinGW the build creates artificial import libraries with dlltool 
from .def files.  While trying to build 2.28 I came across a possible 
incompatibility between the implib generated by dlltool and auto-import 
linkage:

$ gcc -shared -Wl,--out-implib,libtest.dll.a -o cygtest.dll libtest.c
Creating library file: libtest.dll.a

$ nm libtest.dll.a | grep -v ' [bdit] '

d000003.o:
00000000 I _cygtest_dll_iname

d000000.o:
00000000 I __head_cygtest_dll
          U _cygtest_dll_iname

d000002.o:
          U __head_cygtest_dll
00000000 I __imp__test_func
00000000 T _test_func

d000001.o:
          U __head_cygtest_dll
00000000 I __imp__test_data
00000000 I __nm__test_data

$ gcc -o test.exe test.c libtest.dll.a

# now let's try with dlltool
$ dlltool --dllname cygtest.dll --input-def libtest.def --output-lib 
libtest.dll.a

$ nm libtest.dll.a | grep -v ' [bdit] '

deobt.o:
00000000 I __libtest_dll_a_iname

deobh.o:
00000000 I __head_libtest_dll_a
          U __libtest_dll_a_iname

deobs00001.o:
          U __head_libtest_dll_a
00000000 I __imp__test_func
00000000 T _test_func

deobs00000.o:
          U __head_libtest_dll_a
00000000 I __imp__test_data
# Note no __nm__test_data auto-import here

$ gcc -o test.exe test.c libtest.dll.a
fu000001.o:(.idata$2+0xc): undefined reference to `_libtest_dll_a_iname'
nmth000000.o:(.idata$4+0x0): undefined reference to `__nm__test_data'
collect2: ld returned 1 exit status


Yaakov

--------------050201050905050707060801
Content-Type: text/plain;
 name="libtest.c"
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
 filename="libtest.c"

__declspec(dllexport) int test_data = 42;
__declspec(dllexport) int test_func(void) { return test_data; }

--------------050201050905050707060801
Content-Type: text/plain;
 name="libtest.def"
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
 filename="libtest.def"

EXPORTS
test_func
test_data DATA

--------------050201050905050707060801
Content-Type: text/plain;
 name="test.c"
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
 filename="test.c"

extern int test_data;
extern int test_func(void);

int
main(void) {
	int foo = test_data;
	test_func();
	return 0;
}


--------------050201050905050707060801
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
--------------050201050905050707060801--

- Raw text -