Sourceware Bugzilla – Bug 13710
[Regression] .def files containing LIBRARY statement can't be parsed any more
Last modified: 2012-02-24 14:24:53 UTC
In the last couple of days a change was applied to binutils which makes the behaviour of the processing of .def files more strict. Due to this change some libraries fail to compile, for example cairo.
The .def file which is used by cairo contains something along the lines of this:
This used to work fine with binutils 18.104.22.16820113, but when using binutils 22.214.171.12420216 this results in the following error:
/usr/lib64/gcc/i686-w64-mingw32/4.7.0/../../../../i686-w64-mingw32/bin/ld: a.def:3: syntax error
/usr/lib64/gcc/i686-w64-mingw32/4.7.0/../../../../i686-w64-mingw32/bin/ld:a.def: file format not recognized; treating as linker script
/usr/lib64/gcc/i686-w64-mingw32/4.7.0/../../../../i686-w64-mingw32/bin/ld:a.def:2: syntax error
collect2: error: ld returned 1 exit status
After some discussion with Kai Tietz we came to the conclusion that these type of .def files are invalid according to MSDN: http://msdn.microsoft.com/en-us/library/d91k01sh%28v=vs.80%29.aspx
This documentation indicates that .def files must start with the 'LIBRARY xxx.dll' statement followed by the 'EXPORTS' statement, so in this regard the more strict behaviour of binutils is correct.
So I tried fixing cairo so that it uses a .def file which looks like this:
While doing so I noticed that libtool also tries to do some funny things with the .def file:
libtool: link: if test "x`/bin/sed 1q .libs/libcairo.def`" = xEXPORTS; then cp .libs/libcairo.def .libs/libcairo-2.dll.def; else echo EXPORTS > .libs/libcairo-2.dll.def; cat .libs/libcairo.def >> .libs/libcairo-2.dll.def; fi
It looks like libtool always checks the first line of the given .def file. If this first line isn't 'EXPORTS' then it will be automatically added to the resulting .def file. Given the .def file above, the resulting .def file will become:
This .def file isn't accepted by binutils as well.
So to fix all this, changes have to be applied to both cairo and libtool. However, the annoying thing with libtool is that every libtool-using piece of software is bundling their own copy of libtool so it will take quite some time before a patched version of libtool is really in use. While I agree that binutils should be as compliant and strict as possible I think that the damage here is worse than the benefits. So I would like to suggest that this change in behaviour in binutils is reverted to the old behaviour (for now) and that we also try to get this fixed properly in libtool, cairo and perhaps several other pieces of software.
Filed bugs for libtool and cairo:
Module name: src
Changes by: firstname.lastname@example.org 2012-02-24 14:20:19
binutils : ChangeLog defparse.y
binutils/doc : binutils.texi
ld : ChangeLog deffilep.y
* defparse.y (keyword_as_name): Disable LIBRARY
* doc/binutils.texi: Document LIBRARY exception.
* deffilep.y (keyword_as_name): Disable LIBRARY