Re: Reproducible binary builds [was: complibs/zlib: Add zlib support for binutils and gdb]

["Yann E. MORIN" <yann dot morin dot 1998 at anciens dot enib dot fr>]

Michael, Zhenqiang, All,

On Thursday 24 November 2011 23:26:41 Michael Hope wrote:
> Hi there.  I thought I'd pop this out of the zlib discussion as the
> thread was getting a bit deep.  Take it back to the top level
> requirements and such.
> 
> We're looking at making and distributing a binary build of the Linaro
> toolchain for ARM.
> 
> We want:
>  * A generic Linux build that runs on most distros from RHEL 5 onwards
>  * A Windows build that runs on Windows XP and up
>  * Support for 32 bit and 64 bit hosts
> 
> and various qualities that go with that:
>  * Reproducible builds
>  * A sharable build system so others can reproduce and customise the build
>  * A minimum number of binaries, meaning that the binary should run on
> 32 and 64 bit hosts
>  * To minimise testing by making the Windows and Linux builds as
> similar as possible

OK, this is nice to see the overall goal, explained in precise terms.
Thanks!

> To do this it makes sense to:
>  * Use the same build scripts (i.e. crosstool-NG) for Windows and Linux
>  * Use the same library and application versions
>  * Build everything from scratch
> 
> We could pick something like Ubuntu 8.04 LTS and build on that to lock
> down the library versions, but that makes it hard to have the same
> version on Windows and harder for others to reproduce the build.
> 
> We could use the prebuilt mingw/msys versions of libraries (such as
> http://sourceforge.net/projects/mingw/files/MinGW/Base/libiconv/libiconv-1.14-2/)
> but then the Windows and Linux versions would be different.
> 
> There's a few options for running on a range of Linuxs':
>  1. Statically link everything (lose any security/bug fixes)
>  2. Statically link everything but libc and libm
>  3. Use LSB
>  4. Ship dynamic libraries and pick them up using RPATH
> 
> A 32 bit version of (1) ill work out-of-the-box on 32 bit and 64 bit
> hosts.  None of the rest will as 64 bit hosts don't include the 32 bit
> libraries by default, but they're pretty close and just a 'apt-get
> install lsb' or 'yum install redhat-lsb.i386' away.
> 
> The biggest thing is to use the same versions on Windows and Linux
> which really means building from scratch.  Re-using the crosstool-NG
> infrastructure makes more sense then doing it outside.  I'm happy to
> keep these patches in our own tree so that it doesn't pollute tip and
> increase the number of packages you need to support.

OK, that all makes a lot of sense! So, here is the list of the required
dependencies (that I know of) for each component:

   library   | binutils | gcc | gdb |
   ----------+----------+-----+-----+
   expat     |          |     |  Y  |
   ncurses   |          |     |  Y  |
-> zlib      |    Y     |  Y  |  Y  |
-> libiconv  |    Y     |  Y  |  Y  |
   gmp       |          |  Y  |     |
   mpfr      |          |  Y  |     |
   ppl       |          |  Y  |     |
   cloog/ppl |          |  Y  |     |
   mpc       |          |  Y  |     |
   libelf    |          |  Y  |     |

I believe this is a complete listing. If not, then please add to it.
I think that the discussion so far was enough to warrant inclusion of
those libs in the build process. The two that are missing are zlib
and libiconv. I think we can live with adding only these two libs.

I'm pretty busy these days, so I won't be able to really work on this
until Tuesday, though.

Regards,
Yann E. MORIN.

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