Packaging Guidelines for MinGW Windows cross-compiler
Please note this is a draft. "Rationale" sections are for discussion and will be deleted from the final document.
Naming
Packages should be named by prefixing the upstream package name
with mingw-
Rationale Debian name their packages mingw32-*.
However I can't see a reason for including '32' in the name, particularly
since (a) the upstream package is just called mingw and (b)
we may want to build 64 bit binaries.
Base packages
The base packages provide a root filesystem, base libraries,
binutils (basic programs like 'strip', 'ld' etc), the compiler (gcc)
and the Win32 API. Packages may need to depend on one or more of
these. In particular, almost any conceivable package should
depend on mingw-runtime.
mingw-filesystem |
Core filesystem directory layout, and RPM macros for spec files. Equivalent to 'filesystem' RPM |
mingw-runtime |
Base libraries for core MinGW runtime & development environment. Equivalent to 'glibc' RPM |
mingw-binutils |
Cross-compiled binutils (utilities like 'strip', 'as', 'ld') which understand Windows executables and DLLs. Equivalent to 'binutils' RPM |
mingw-w32api |
Win32 API. A free (public domain) reimplementation of the header files required to link to the Win32 API. No direct equivalent in base Fedora - 'glibc' is closest |
mingw-gcc |
GNU compiler collection. Compilers for C and C++ which cross-compile to a Windows target. Equivalent to 'gcc' RPM |
Rationale I've used the same names as the upstream packages, and also the same names as Debian (minus the unnecessary '32' which Debian has in the name).
Filesystem layout
[root]
|
+- etc
| |
| +- rpm
| |
| +- macros.mingw
|
+- usr
|
+- bin - Links to cross compiler toolchain
| |
| +- i686-pc-mingw-cpp
| +- i686-pc-mingw-gcc
| +- i686-pc-mingw-g++
| +- ... etc..
|
+- lib
| |
| +- rpm
| |
| +- mingw-defs - custom helper scripts for auto-requires, binary stripping, etc
| +- mingw-find-provides.sh - extra DLL names
| +- mingw-find-requires.sh - discover required DLL names
|
+- i686-pc-mingw - root of mingw toolchain and binaries - see next diagram
[mingw-root]
|
+- bin - Cross compiler toolchain
| |
| +- cpp
| +- gcc
| +- g++
| +- ... etc ...
|
+- lib - Cross compiler toolchain support libraries / files
|
+- sys-root - root for cross compiled binaries
|
+- mingw
|
+- bin - cross-compiled binaries & runtime DLL parts
+- doc - documentation
+- include - include files for cross compiled libs
+- lib - cross-compiled static libraries & linktime DLL parts
| |
| +- pkgconfig - pkg-config definitions for libraries
|
+- share
|
+- man
Standard mingw RPM macros
The mingw-filesystem package provides a number of convenience macros for the cross compiled sysroot directories, and toolchain. It is mandatory to use these macros in all mingw packages submitted to Fedora.
Toolchain macros
The following macros are for the %build and %install section of the spec
| _mingw_ar | i686-pc-mingw32-ar | cross compiler 'ar' binary |
| _mingw_cc | i686-pc-mingw32-gcc | cross compiler 'gcc' binary |
| _mingw_cflags | -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions --param=ssp-buffer-size=4 -I%{_mingw_includedir} | Rationale: we need to remove the -m64 flag from standar RPM_OPTS_FLAGS |
| _mingw_configure | CC="%{_mingw_cc}" CFLAGS="%{_mingw_cflags}" ./configure --build=%_build --host=%{_mingw_host} --target=%{_mingw_target} --prefix=%{_mingw_prefix} | standard invocation for autotools 'configure' scripts |
| _mingw_cpp | i686-pc-mingw32-gcc -E | cross compiler 'cpp' binary |
| _mingw_host | i686-pc-mingw32 | Host platform for build |
| _mingw_objdump | i686-pc-mingw32-objdump | cross compiler 'objdump' binary |
| _mingw_ranlib | i686-pc-mingw32-ranlib | cross compiler 'ranlib' binary |
| _mingw_strip | i686-pc-mingw32-strip | cross compiler 'strip' binary |
| _mingw_target | i686-pc-mingw32 | Target platform for build |
Filesystem location macros
The following macros are for use in %build, %install and %files sections of the RPM spec
| _mingw_bindir | %{_mingw_prefix}/bin |
| _mingw_datadir | %{_mingw_prefix}/share |
| _mingw_docdir | %{_mingw_prefix}/share/doc |
| _mingw_includedir | %{_mingw_prefix}/include |
| _mingw_libdir | %{_mingw_prefix}/lib |
| _mingw_libexecdir | %{_mingw_prefix}/libexec |
| _mingw_mandir | %{_mingw_prefix}/share/man |
| _mingw_prefix | %{_mingw_sysroot}/mingw |
| _mingw_sbindir | %{_mingw_prefix}/sbin |
| _mingw_sysconfdir | %{_mingw_prefix}/etc |
| _mingw_sysroot | %{_prefix}/i686-pc-mingw32/sys-root |
Naming of the cross-compilers and binutils
The cross-compilers and binutils are Fedora binaries and are therefore placed in %{_bindir} (ie. /usr/bin) according to the FHS and Fedora guidelines.
The cross-compilers and binutils which generate i686 binaries for Windows are named:
%{_bindir}/i686-pc-mingw32-gcc
%{_bindir}/i686-pc-mingw32-g++
%{_bindir}/i686-pc-mingw32-ld
%{_bindir}/i686-pc-mingw32-as
%{_bindir}/i686-pc-mingw32-strip
etc.
The same binaries are present in %{_prefix}/i686-pc-mingw32/bin without any prefix in the name, ie:
%{_prefix}/i686-pc-mingw32/bin/gcc
%{_prefix}/i686-pc-mingw32/bin/g++
%{_prefix}/i686-pc-mingw32/bin/ld
%{_prefix}/i686-pc-mingw32/bin/as
%{_prefix}/i686-pc-mingw32/bin/strip
etc.
Note that we don't support generating x86-64 binaries (or any other architecture) at the moment, but if we do those will have a different prefix.
Rationale This is the name which autoconf configure scripts expect when they are
invoked in cross-compiling mode. The /usr/i686-pc-mingw32/bin
directory is required by GCC, otherwise it invokes the wrong assembler and linker.
Naming of the root filesystem
The root filesystem contains Windows executables and DLLs and any other Windows-only files. It is necessary both because we need to store Windows libraries in order to link further libraries which depend on them, and also because MinGW requires a root filesystem location. The location (for i686 target) is provided by the macro:
%{_mingw_sysroot} %{_prefix}/i686-pc-mingw/sys-root
Rationale This is what the existing Fedora packages do, and very similar to what Debian is doing (they use a different and inconsistent name, but it is still a directory located directly under /usr), and is what MinGW expects.
Packaging DLLs
The Fedora MinGW SIG packages a range of common Linux libraries as Windows DLLs so that further libraries/programs can be compiled against them.
These libraries should be packaged in the directory provided by the macro:
%{_mingw_libdir} %{_mingw_sysroot}/lib
Rationale Specified by MinGW. Putting them in %{_libdir} is not desirable because they are not intended for use on the host system. They are cross-compiled binaries only executable on the Windows platform, or under an environment like Wine.
Packaging EXEs
Any Windows binaries should be packaged in the directory given by the macro:
%{_mingw_bindir} %{_mingw_sysroot}/bin
Rationale Specified by MinGW. Not applicable for /usr/bin as these are cross-compiled binaries only intended for execution under Windows, or an environment like Wine.
Packaging header files and other auxiliary files
Any auxiliary Windows files should be placed in the standard subdirectories of the root filesystem, for example:
%{_mingw_includedir} %{_mingw_sysroot}/include
%{_mingw_datadir} %{_mingw_sysroot}/share
etc.
Dependencies
If a package contains binaries which depend on a DLL provided by another package, these dependencies should be expressed in the form:
mingw(foo.dll)
where foo.dll is the name of the DLL. The name must be converted to lowercase because Windows binaries contain case insensitive dependencies.
All packages should depend on mingw-filesystem.
Correct dependency generation is done automatically. Packagers should include this line in all library packages:
%include /usr/lib/rpm/mingw-defs
All specfiles should BuildRequire at least:
BuildRequires: mingw-filesystem >= minimum-version
and any other BuildRequires at they need.
Build architecture
All packages should have:
BuildArch: noarch
unless they contain Fedora native executables.
Rationale Windows executables always target 32 bit x86 at present, and so (in theory) should be identical whatever Fedora architecture was used to build or host them.
Libraries (DLLs)
All libraries must be built as DLLs.
Because of the peculiarity of Windows, DLLs are stored in the %{_mingw_bindir} directory, along with a control file in the %{_mingw_libdir} directory. For example, for a library called foo there would be:
%{_mingw_bindir}/foo.dll
%{_mingw_bindir}/foo.def
%{_mingw_libdir}/foo.dll.a
%{_mingw_libdir}/foo.la
All files are required in those locations in order to link successfully, except that the .def file is not always built by libtool for reasons unknown, and the .dll may contain a version number although not always (eg. foo-0.dll).
Do not use wildcards for %{_mingw_bindir} in %files section
The %files section must list DLLs separately. Packages must NOT use %{_mingw_bindir}/*
Rationale Libtool is very fragile and will give up on building a DLL very easily. Therefore we force the name of the DLL to be listed explicitly in the %files section in order to catch this during RPM builds.
Static libraries
In accordance with ordinary Fedora policy, static libraries should not be built, and if they are then they should be placed in a -static subpackage.
The exception is the base package mingw-w32api which contains static libraries that are required for GCC to create executables.
Stripping
Libraries and executables should be stripped. This is carried out automatically if the mingw-defs file is included in the spec.