PackagingDrafts/MinGWCrossCompiler

Packaging Guidelines for MinGW Cross Compilers

Updated Guidelines
These guidelines apply to all current Fedora releases. For RHEL-5 and RHEL-6 the old guidelines still apply which can be be found here: Packaging:MinGW_Old

Introduction

The Fedora MinGW project's mission is to provide an excellent development environment for Fedora users who wish to cross-compile their programs to run on Windows, minimizing the need to use Windows at all. In the past developers have had to port and compile all of the libraries and tools they have needed, and this huge effort has happened independently many times over. We aim to eliminate duplication of work for application developers by providing a range of libraries and development tools which have already been ported to the MinGW cross-compiler environment. This means that developers will not need to recompile the application stack themselves, but can concentrate just on the changes needed to their own application.

As of Fedora 17 a set of RPM macros and packages have been introduced which help packagers compile binaries for multiple targets. The targets Win32 and Win64 are supported.

Track Fedora native package versions

In general terms, cross-compiled MinGW versions of packages which are already natively available in Fedora, should follow the native Fedora package as closely as possible. This means they should stay at the same version, include all the same patches as the native Fedora package, and be built with the same configuration options.

The MinGW SIG have written an RPM comparison tool which makes it possible to compare cross compiled MinGW packages with the Fedora native packages, in order to determine whether versions, patches and configuration are aligned.

Follow Fedora policy

Cross compiled MinGW packages must follow Fedora policy, except where noted in this document. Cross compiled packages go through the same review process, GIT admin process etc as other Fedora packages.

Package naming

MinGW packages require special naming to denote the appropriate CPU architecture the binaries have been built for. There should never be a package prefixed with mingw- output during a build. The mingw- prefix is exclusive for RPM spec file names and the source RPM file name. The CPU architecture specific packages are created by sections with %files -n mingw32-foo or %files -n mingw64-foo.

mingw-	Used for source package and RPM spec name
mingw32-	Used for packages which are built for Win32
mingw64-	Used for packages which are built for Win64

Base packages

The base packages provide a root filesystem, base libraries, binutils (basic programs like 'strip', 'ld' etc), the compiler (gcc) and the Win32/Win64 API. Packages may need to depend on one or more of these. In particular, almost all packages should BuildRequire mingw32-filesystem, mingw64-filesystem, mingw32-gcc and mingw64-gcc. The correct Requires flags will get added automatically when the %{?mingw_package_header} macro is mentioned in the spec file (as will be described later on in these guidelines)

mingw32-filesystem / mingw64-filesystem	Core filesystem directory layout, and RPM macros for spec files. Equivalent to 'filesystem' RPM
mingw32-binutils / mingw64-binutils	Cross-compiled binutils (utilities like 'strip', 'as', 'ld') which understand Windows executables and DLLs. Equivalent to 'binutils' RPM
mingw32-gcc / mingw64-gcc	GNU compiler collection. Compilers for C and C++ which cross-compile to a Windows target. Equivalent to gcc RPM
mingw32-crt / mingw64-crt	Base libraries for core MinGW runtime & development environment. Equivalent to 'glibc' RPM
mingw32-headers / mingw64-headers	Win32 and Win64 API. A free (public domain) reimplementation of the header files required to link to the Win32 and Win64 API. No direct equivalent in base Fedora - glibc-devel is closest

Build for multiple targets

The goal of the MinGW framework is to provide an easy way for package maintainers to build their packages for multiple targets using one .spec file. To aid developers in this several RPM macros have been developed which are part of the mingw-filesystem package. These RPM macros will be explained later on in these guidelines.

By default a MinGW package will be built for both the Win32 and Win64 targets.

When a package can only be built for either one of these targets this can be indicated by setting one of these:

%global mingw_build_win32 0	Don't build for the Win32 target
%global mingw_build_win64 0	Don't build for the Win64 target

One source RPM, separate binary RPMs per-target

Each cross compiled MinGW package which builds binaries for a specific target should put the binaries for that target in a separate subpackage. So if a package foo builds binaries for the Win32 and Win64 targets, then the source RPM should provide two subpackages named mingw32-foo and mingw64-foo.

This means that a spec file must contains %package and %files sections for all the targets.

If a package contains translations then all calls to the %find_lang must be replaced by %mingw_find_lang. This causes all translation filelists to be split in per-target filelists. For example: when a spec file contains something like this:

 %install
 <snip>
 %mingw_find_lang foo

then two files will get created named mingw32-foo.lang and mingw64-foo.lang. These file lists can be included in the %files section for the targets:

 %files -n mingw32-foo -f mingw32-foo.lang
 <snip>
 %files -n mingw64-foo -f mingw64-foo.lang

Filesystem layout

[root]
  |
  +- etc
  |   |
  |   +- rpm
  |       |
  |       +- macros.mingw
  |       +- macros.mingw32
  |       +- macros.mingw64
  |
  +- usr
      |
      +- bin   - Links to MinGW cross compiler toolchain
      |   |
      |   +- i686-w64-mingw32-cpp
      |   +- i686-w64-mingw32-gcc
      |   +- i686-w64-mingw32-g++
      |   +- x86_64-w64-mingw32-cpp
      |   +- x86_64-w64-mingw32-gcc
      |   +- x86_64-w64-mingw32-g++
      |   +- ... etc..
      |
      +- lib
      |   |
      |   +- rpm
      |       |
      |       +- mingw-find-debuginfo.sh - extract debug information from Win32 and Win64 binaries
      |       +- mingw-find-lang.sh - generates per-target file lists containing translations
      |       +- mingw-find-provides.sh - extra DLL names
      |       +- mingw-find-requires.sh - discover required DLL names
      |
      +- i686-w64-mingw32  - root of mingw toolchain and binaries for the Win32 target - see next diagram
      +- x86_64-w64-mingw32  - root of mingw toolchain and binaries for the Win64 target - see next diagram

/usr/i686-w64-mingw32
/usr/x86_64-w64-mingw32
  |
  +- bin  - Binutils toolchain binaries for the target
  |   |
  |   +- ar
  |   +- as
  |   +- dlltool
  |   +- ld
  |   +- ... etc ...
  |
  +- lib  - Binutils toolchain support libraries / files for the target
  |
  +- sys-root  - root for cross compiled MinGW binaries
      |
      +- mingw
          |
          +- bin     - cross-compiled MinGW binaries & runtime DLL parts
          +- etc     - configuration files
          +- include - include files for cross compiled MinGW libs
          +- lib     - cross-compiled static MinGW libraries & linktime DLL parts
          |   |
          |   +- pkgconfig  - pkg-config definitions for libraries
          |
          +- share
              |
              +- man

Filenames of the cross-compilers and binutils

The MinGW cross-compilers and binutils are Fedora binaries and are therefore placed in %{_bindir} (ie. /usr/bin) according to the FHS and Fedora guidelines.

The MinGW cross-compilers and binutils which generate i686 binaries for Windows are named:

 %{_bindir}/i686-w64-mingw32-gcc
 %{_bindir}/i686-w64-mingw32-g++
 %{_bindir}/i686-w64-mingw32-ld
 %{_bindir}/i686-w64-mingw32-as
 %{_bindir}/i686-w64-mingw32-strip
 etc.

The same binaries are present in %{_prefix}/i686-w64-mingw32/bin without any prefix in the name, ie:

 %{_prefix}/i686-w64-mingw32/bin/gcc
 %{_prefix}/i686-w64-mingw32/bin/g++
 %{_prefix}/i686-w64-mingw32/bin/ld
 %{_prefix}/i686-w64-mingw32/bin/as
 %{_prefix}/i686-w64-mingw32/bin/strip
 etc.

The same also applies for the x86_64 target. This target uses 'x86_64-w64-mingw32' as prefix instead of 'i686-w64-mingw32'

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 Win32 target is provided by the macro:

 %{mingw32_sysroot}   %{_prefix}/i686-w64-mingw32/sys-root

And the Win64 target is provided by the macro:

 %{mingw64_sysroot}   %{_prefix}/x86_64-w64-mingw32/sys-root

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 cross compiled packages submitted to Fedora.

Toolchain macros

The following macros are for the %build and %install section of the spec

Generic macros:

Macro	Available in mingw-filesystem	Explanation
mingw_cmake	>= 95	Call the cmake binary for all the configured targets
mingw_cmake_kde4	>= 95	Call the cmake binary for all the configured targets with KDE4 specific parameters set
mingw_configure	>= 95	Call the configure command for all the configured targets
mingw_make	>= 95	Call the 'make' command for all the configured targets
mingw_objcopy	>= 95	cross compiler 'objcopy' binary (which supports both Win32 and Win64 binaries)
mingw_objdump	>= 95	cross compiler 'objdump' binary (which supports both Win32 and Win64 binaries)
mingw_qmake_qt4	>= 95	Call the Qt4 qmake binary for all configured targets (requires mingw32-qt-qmake and/or mingw64-qt-qmake to be installed)
mingw_qmake_qt5	>= 96	Call the Qt5 qmake binary for all configured targets (requires mingw32-qt5-qmake and/or mingw64-qt5-qmake to be installed)
mingw_strip	>= 95	cross compiler 'strip' binary (which supports both Win32 and Win64 binaries)

Win32 specific macros:

Macro	Available in mingw32-filesystem	Value	Explanation
mingw32_ar	>= 95	i686-w64-mingw32-ar	cross compiler 'ar' binary
mingw32_cc	>= 95	i686-w64-mingw32-gcc	cross compiler 'gcc' binary
mingw32_cflags	>= 95	-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions --param=ssp-buffer-size=4	Default compiler flags for C/C++ binaries
mingw32_cmake	>= 95		Call the cmake binary for the Win32 target
mingw32_configure	>= 95		standard invocation for autotools 'configure' scripts
mingw32_cpp	>= 95	i686-w64-mingw32-gcc -E	cross compiler 'cpp' binary
mingw32_env	>= 95		Set the correct environment variables for the Win32 target
mingw32_host	>= 95	i686-w64-mingw32	Host platform for build
mingw32_objcopy	>= 95	i686-w64-mingw32-objcopy	cross compiler 'objcopy' binary
mingw32_objdump	>= 95	i686-w64-mingw32-objdump	cross compiler 'objdump' binary
mingw32_pkg_config	>= 95	i686-w64-mingw32-pkg-config	Call the pkg-config command for the Win32 target
mingw32_qmake_qt4	>= 95	mingw32-qmake-qt4	Call the Qt4 qmake command for the Win32 target
mingw32_qmake_qt5	>= 96	mingw32-qmake-qt5	Call the Qt5 qmake command for the Win32 target
mingw32_ranlib	>= 95	i686-w64-mingw32-ranlib	cross compiler 'ranlib' binary
mingw32_strip	>= 95	i686-w64-mingw32-strip	cross compiler 'strip' binary
mingw32_target	>= 95	i686-w64-mingw32	Target platform for build

Win64 specific macros:

Macro	Available in mingw64-filesystem	Value	Explanation
mingw64_ar	>= 95	x86_64-w64-mingw32-ar	cross compiler 'ar' binary
mingw64_cc	>= 95	x86_64-w64-mingw32-gcc	cross compiler 'gcc' binary
mingw64_cflags	>= 95	-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions --param=ssp-buffer-size=4	Default compiler flags for C/C++ binaries
mingw64_cmake	>= 95		Call the cmake binary for the Win64 target
mingw64_configure	>= 95		standard invocation for autotools 'configure' scripts
mingw64_cpp	>= 95	x86_64-w64-mingw32-gcc -E	cross compiler 'cpp' binary
mingw64_env	>= 95		Set the correct environment variables for the Win64 target
mingw64_host	>= 95	x86_64-w64-mingw32	Host platform for build
mingw64_objcopy	>= 95	x86_64-w64-mingw32-objcopy	cross compiler 'objcopy' binary
mingw64_objdump	>= 95	x86_64-w64-mingw32-objdump	cross compiler 'objdump' binary
mingw64_pkg_config	>= 95	x86_64-w64-mingw32-pkg-config	Call the pkg-config command for the Win64 target
mingw64_qmake_qt4	>= 95	mingw64-qmake-qt4	Call the Qt4 qmake command for the Win64 target
mingw64_qmake_qt5	>= 96	mingw64-qmake-qt5	Call the Qt5 qmake command for the Win64 target
mingw64_ranlib	>= 95	x86_64-w64-mingw32-ranlib	cross compiler 'ranlib' binary
mingw64_strip	>= 95	x86_64-w64-mingw32-strip	cross compiler 'strip' binary
mingw64_target	>= 95	x86_64-w64-mingw32	Target platform for build

Filesystem location macros

The following macros are for use in %build, %install and %files sections of the RPM spec

For the Win32 target:

mingw32_bindir	%{mingw32_prefix}/bin	Location of Windows executables.
mingw32_datadir	%{mingw32_prefix}/share	Shared data used under Windows.
mingw32_docdir	%{mingw32_prefix}/share/doc	Documentation.
mingw32_infodir	%{mingw32_prefix}/share/info	Info files (see note below).
mingw32_includedir	%{mingw32_prefix}/include	Header files used when cross-compiling for Windows.
mingw32_libdir	%{mingw32_prefix}/lib	Windows libraries (see sections below).
mingw32_libexecdir	%{mingw32_prefix}/libexec
mingw32_mandir	%{mingw32_prefix}/share/man	Man pages (see note below).
mingw32_prefix	%{mingw32_sysroot}/mingw	Windows equivalent of %{_prefix}, required by MinGW.
mingw32_sbindir	%{mingw32_prefix}/sbin
mingw32_sysconfdir	%{mingw32_prefix}/etc	Configuration files used when running under Windows.
mingw32_sysroot	%{_prefix}/i686-w64-mingw32/sys-root	Windows system root.

For the Win64 target:

mingw64_bindir	%{mingw64_prefix}/bin	Location of Windows executables.
mingw64_datadir	%{mingw64_prefix}/share	Shared data used under Windows.
mingw64_docdir	%{mingw64_prefix}/share/doc	Documentation.
mingw64_infodir	%{mingw64_prefix}/share/info	Info files (see note below).
mingw64_includedir	%{mingw64_prefix}/include	Header files used when cross-compiling for Windows.
mingw64_libdir	%{mingw64_prefix}/lib	Windows libraries (see sections below).
mingw64_libexecdir	%{mingw64_prefix}/libexec
mingw64_mandir	%{mingw64_prefix}/share/man	Man pages (see note below).
mingw64_prefix	%{mingw64_sysroot}/mingw	Windows equivalent of %{_prefix}, required by MinGW.
mingw64_sbindir	%{mingw64_prefix}/sbin
mingw64_sysconfdir	%{mingw64_prefix}/etc	Configuration files used when running under Windows.
mingw64_sysroot	%{_prefix}/x86_64-w64-mingw32/sys-root	Windows system root.

Compilation of binaries

In order to build binaries for multiple targets we have to call commands like ./configure and make multiple times (once for each target). If one has to write this all out in a spec file then it will lead to duplicate code. To reduce the amount of duplication, several RPM macros have been introduced to help with the compilation. These macros are %mingw_configure, %mingw_cmake, %mingw_cmake_kde4, %mingw_qmake_qt4, %mingw_qmake_qt5 and %mingw_make

These macros use out of source compilation to build binaries for all the targets. Almost all packages support out of source compilation or require slight patching. The only known exceptions to date are zlib and openssl. Packages which don't support out of source compilation may require a different approach like performing everything in the %install phase. If you happen to stumble across a package which requires a different approach feel free to contact us on the Fedora MinGW mailing list

Some packages need to be built multiple times for each target. Examples of this are packages which have to be built once for a static version and once for a shared version. Such packages can add a custom suffix to the build directory used. Say you've got something like below:

 mkdir build_shared
 pushd build_shared
 %{mingw32_configure} --enable-shared
 popd
 mkdir build_static
 pushd build_static
 %{mingw32_configure} --enable-static
 popd

This can be rewritten to something like this:

 MINGW_BUILDDIR_SUFFIX=shared %mingw_configure --enable-shared
 MINGW_BUILDDIR_SUFFIX=static %mingw_configure --enable-static

Most packages used the command make %{?_smp_mflags} to build the package. In the MinGW cross compiler framework you have to use %mingw_make %{?_smp_mflags} to build the package for all configured targets. As with the %mingw_configure macro you can also use the MINGW_BUILDDIR_SUFFIX environment variable to indicate a custom suffix to the build directory used

To install the package the command make install DESTDIR=$RPM_BUILD_ROOT was used in almost all cases. This can be rewritten to %mingw_make install DESTDIR=$RPM_BUILD_ROOT to install the package for all configured targets The environment variable MINGW_BUILDDIR_SUFFIX can also be used here

Some packages require some custom instructions before the files are ready to be packaged. Such code can remain as is. However, you may need to duplicate these instructions multiple times (for all configured targets).

Dependencies

If a package contains binaries which depend on a DLL provided by another package, these dependencies should be expressed in the form:

 mingw32(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. The form 'mingw32(foo.dll)' should be used for Win32 binaries and the form 'mingw64(foo.dll)' for Win64 binaries.

Correct dependency generation is done automatically. Packagers should start their spec files with this line:

 %{?mingw_package_header}

All binary packages should depend on mingw32-filesystem or mingw64-filesystem (depending on the files in the package). If the line mentioned above is used then it will be added automatically, so you don't have to add it yourself

All specfiles should BuildRequire at least one of these (depending on the targets for which you want to build):

BuildRequires:  mingw32-filesystem >= minimum-version
BuildRequires:  mingw64-filesystem >= minimum-version

and any other BuildRequires that they need.

The minimum-version must be at least 95 or any later version which provides the functionality you need

Build architecture

All packages should have:

BuildArch: noarch

unless they contain Fedora native executables.

Libraries (DLLs)

All libraries must be built as DLLs.

Because of the peculiarity of Windows, DLLs are stored in the %{mingw32_bindir} directory, along with a control file in the %{mingw32_libdir} directory. For example, for a library called foo there would be:

 %{mingw32_bindir}/foo.dll
 %{mingw32_libdir}/foo.dll.a

The foo.dll file is the main library, foo.dll.a is a stub linked to applications so they can find the library at runtime. All of these files are required in those locations in order to link successfully. The .dll may contain a version number although not always (eg. foo-0.dll).

Do not use %{mingw32_bindir}/* or %{mingw32_libdir}/* in %files section

The %files section must list DLLs and import libraries separately. Packages must NOT use %{mingw32_bindir}/* or %{mingw32_libdir}/*

The reason for this is that 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.

Manpages and info files

If manpages or info files are simply duplicates of equivalent documentation found in Fedora native packages, then they should not be packaged in the MinGW package.

Stripping

Libraries and executables should be stripped. This is done correctly and automatically if the spec file starts with this line:

 %{?mingw_package_header}

%mingw_package_header
The %mingw_package_header macro sets the strip, objdump, and debuginfo generating commands appropriately for windows binaries. Without this line Windows binaries may be corrupted by the automatic tasks that rpm performs on the built binaries.

Debuginfo subpackage

Most binaries contain debugging symbols when the package gets built. To split the debugging symbols to a separate debuginfo package (as is done with native Fedora packages) the spec file must include these lines:

 %{?mingw_package_header}
 [...]
 %{?mingw_debug_package}

The %{?mingw_debug_package} line must be placed after the %description tag. Otherwise spectool and other RPM tools may fail to function

Example Specfile

%{?mingw_package_header}

Name:           mingw-example
Version:        1.0.0
Release:        1%{?dist}
Summary:        MinGW compiled example library

License:        LGPLv2+
URL:            http://fedoraproject.org
Source0:        http://fedoraproject.org/example-%{version}.tar.bz2

BuildArch:      noarch

BuildRequires:  mingw32-filesystem >= 95
BuildRequires:  mingw32-gcc
BuildRequires:  mingw32-binutils
BuildRequires:  mingw32-gettext
BuildRequires:  mingw32-win-iconv
BuildRequires:  mingw32-zlib

BuildRequires:  mingw64-filesystem >= 95
BuildRequires:  mingw64-gcc
BuildRequires:  mingw64-binutils
BuildRequires:  mingw64-gettext
BuildRequires:  mingw64-win-iconv
BuildRequires:  mingw64-zlib


%description
MinGW compiled example library.


# If a package maintainer wishes to bundle static libraries then they
# can be placed in -static subpackages. Otherwise, the -static subpackages
# can be dropped

# Win32
%package -n mingw32-example
Summary:       MinGW compiled example library for the Win32 target

%description -n mingw32-example
MinGW compiled example library for the Win32 target.

%package -n mingw32-example-static
Summary:       Static version of the MinGW Win32 compiled example library
Requires:      mingw32-example = %{version}-%{release}

%description -n mingw32-example-static
Static version of the MinGW Win32 compiled example library.

# Win64
%package -n mingw64-example
Summary:       MinGW compiled example library for the Win64 target

%description -n mingw64-example
MinGW compiled example library for the Win64 target.

%package -n mingw64-example-static
Summary:       Static version of the MinGW Win64 compiled example library
Requires:      mingw64-example = %{version}-%{release}

%description -n mingw64-example-static
Static version of the MinGW Win64 compiled example library.


%{?mingw_debug_package}


%prep
%setup -q -n example-%{version}


%build
%mingw_configure --enable-static --enable-shared --enable-foo
%mingw_make %{?_smp_mflags}


%install
%mingw_make install DESTDIR=$RPM_BUILD_ROOT

# Libtool files don't need to be bundled
find $RPM_BUILD_ROOT -name "*.la" -delete

%mingw_find_lang example


# Note: there should be no %%files section for the main package!

# Static subpackages are optional (as mentioned earlier)

# Win32
%files -n mingw32-example -f mingw32-example.lang
%{mingw32_bindir}/libexample-0.dll
%{mingw32_includedir}/example/
%{mingw32_libdir}/libexample.dll.a
%{mingw32_libdir}/pkgconfig/example.pc

%files -n mingw32-example-static
%{mingw32_libdir}/libexample.a

# Win64
%files -n mingw64-example -f mingw64-example.lang
%{mingw64_bindir}/libexample-0.dll
%{mingw64_includedir}/example/
%{mingw64_libdir}/libexample.dll.a
%{mingw64_libdir}/pkgconfig/example.pc

%files -n mingw64-example-static
%{mingw64_libdir}/libexample-0.a


%changelog
* Sun Apr 15 2012 Erik van Pienbroek <epienbro@fedoraproject.org> - 1.0.0-1
- Initial release