Features/Mingw-w64 cross compiler

= Mingw-w64 cross compiler =

Summary
Use the mingw-w64 cross compiler toolchain to build binaries for both Win32 and Win64 targets

Owner

 * Name: Erik van Pienbroek


 * Email: epienbro @ fedoraproject.org
 * IRC: epienbro @ irc.freenode.net #fedora-mingw
 * Mailing list: mingw@lists.fedoraproject.org

Current status

 * Targeted release: Fedora 17
 * Last updated: March 11 2012
 * Percentage of completion: 100%

Detailed Description
Several Fedora releases ago support was added to build binaries for the Win32 target using the mingw.org toolchain (Features/Windows_cross_compiler). At the moment there are over 110 packages in Fedora which make use of this toolchain (the mingw32-* packages). There has been a demand to also add support for building binaries for the Win64 target. In order to build binaries for the Win64 target we have to switch from the mingw.org toolchain to the (much better maintained and more complete) mingw-w64 toolchain

In order to make it easy for packagers to build binaries for multiple targets (from a single source rpm) several RPM macros have been developed. These RPM macros are an attempt to reduce the amount of duplication of .spec files to a minimum and are bundled in the mingw-filesystem package (which will replace mingw32-filesystem). All these macros are explained in the updated MinGW packaging guidelines: Packaging:MinGW_Future. These new packaging guidelines are already approved by the FPC

Several RPM packages have been developed like mingw-binutils, mingw-gcc, mingw-headers and mingw-crt containing all pieces belonging to the mingw-w64 toolchain (which can build binaries for both Win32 as well as Win64). These new packages will replace the current mingw32 toolchain packages: mingw32-filesystem, mingw32-binutils, mingw32-gcc, mingw32-w32api and mingw32-crt

With this framework we will also be able to build binaries for the Win32 target using the mingw-w64 toolchain (instead of the mingw.org one). Most packages compile fine out of the box against the mingw-w64 toolchain. All packages which require some patching have been identified and have already been made operational in a testing repository

This testing repository has already been available for about a year and various members from the Fedora MinGW SIG already contributed patches and improvements to it. As we were waiting on legal approval for the introduction of mingw-w64 in Fedora we had to do all development and testing work in this testing repository. As the legal approval arrived at February 22 2012 we can now merge back all the changes from this testing repository back to Fedora after which the testing repository will disappear

Benefit to Fedora
This feature makes it easier for packagers to cross-compile packages for both the Win32 and the Win64 targets. Developers can also use the tools from this framework to cross-compile binaries (and test these using wine) for the Win32 and Win64 targets

Scope
Before this feature can land in Fedora several tasks have to be done:
 * Develop a set of RPM macros to reduce duplication in .spec files done
 * Package the mingw-w64 toolchain done
 * Rebuild all mingw32-* packages against the mingw-w64 toolchain done
 * Patch all mingw32-* packages which failed to build against the mingw-w64 toolchain done
 * Port the most important mingw32-* packages to use the new set of RPM macros so that binaries get build for Win32 and Win64 done
 * Publish testing repositories for the Win32+Win64 tree done
 * Write a porting guide done
 * Rewrite the Fedora MinGW packaging guidelines done
 * Let the updated packaging guidelines be approved done
 * Put the 3 toolchain packages (mingw-filesystem, mingw-headers and mingw-crt) up for review done
 * Wait for the 3 toolchain packages to be reviewed and approved done
 * Have FE-Legal approve the use of the mingw-w64 toolchain done
 * Bootstrap the toolchain for the win32 target done
 * Rebuild all current mingw32 packages against the new mingw-w64 based toolchain done
 * Introduce the mingw-gcc and mingw-binutils packages done
 * Bootstrap the toolchain for the win64 target done

These tasks are not required to be completed for Fedora 17, but are related to this feature:
 * Perform a mass rename of all mingw32-* packages to mingw-* as used by the new MinGW packaging guidelines done
 * Import the renamed mingw-* packages in Fedora 17 done
 * Port the individual mingw-* packages to use this new framework about 70% of all mingw32-* packages are already ported in the testing repository
 * Merge all ported packages from the testing repository back to Fedora in progress

Most of the steps required to get this in Fedora are also explained at the roadmap page

How To Test
The Win32 part of the mingw-w64 toolchain is already part of the Fedora 17 repositories. The exact same RPM macros and wrapper scripts (like mingw32-configure) as used in the MinGW toolchain in earlier Fedora releases can be used to cross-compile packages against this toolchain. The cross-compiled binaries can be tested using wine

Until the remaining packages belonging to the new Fedora MinGW packaging guidelines are imported in Fedora people interested can test this feature using a testing repository. Details about this can be found at the testing repository page. Once you install the yum .repo file belonging to the testing repository and perform a 'yum update' any mingw32-* packages which you might have already installed will be replaced by ones produced using the mingw-w64 toolchain

If you want to test building packages for the Win64 target you can install the 'mingw64-gcc' package. Once the compiler is installed you can build binaries for the Win64 target using commands like 'i686-w64-mingw32-gcc'. Also note that the name of the gcc command for the Win32 target has been changed from 'i686-pc-mingw32' to 'i686-w64-mingw32-gcc' and that all files which used to be in /usr/i686-pc-mingw32/ have now been moved to /usr/i686-w64-mingw32/

Generated binaries for the Win64 target can be tested using the x86_64 version of wine

User Experience
Developers using Fedora can now build binaries for both the Win32 as well as the Win64 target

Dependencies

 * The 3 toolchain packages (mingw-filesystem, mingw-headers and mingw-crt) are new packages and have to pass the package review process done
 * The mingw-headers and mingw-crt packages have to be cleared by FE-Legal done
 * The Fedora MinGW Packaging guidelines have to be updated and approved done

Contingency Plan
If the 3 toolchain packages can't be approved in time we can stick with the current mingw32-* packages and move this feature to the next Fedora release

Documentation
All documentation about the use of the mingw-w64 toolchain to generate binaries for Win32 and Win64 can be found at Packaging:MinGW_Future, MinGW/CrossCompilerFramework and on the mingw@lists.fedoraproject.org mailing list

Release Notes
This release of Fedora contains the mingw-w64 cross compiler toolchain which makes it easier for packagers and developers to build binaries for both the Win32 and the Win64 targets

Comments and Discussion

 * See Talk:Features/Mingw-w64_cross_compiler
 * Announcement on the mingw@lists.fedoraproject.org mailing list
 * Status update request on the legal@lists.fedoraproject.org mailing list
 * Announcement about the legal approval
 * Status update February 25 2012
 * Status update March 3 2012
 * Status update March 6 2012
 * Status update March 7 2012