Re: [PATCH] scripts: support building with the LSB wrappers

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

Michael, All,

On Monday 28 November 2011 00:57:27 Michael Hope wrote:
> # HG changeset patch
> # User Michael Hope <michael.hope@linaro.org>
> # Date 1322438185 -46800
> # Branch lsb
> # Node ID edadd06cb17fd3a45501afe22ae39a76f4a76fa2
> # Parent  49af7802dcd538ec3cb64337030b03ac2c6344d2
> scripts: support building with the LSB wrappers
> 
> If set, look for 'lsbcc' instead of 'gcc' and 'lsbc++ instead of g++
> and use them when building.
> 
> The Linux Standard Base defines a set of libraries and APIs that are
> implemented by most distros.  If you build against these APIs then in
> theory the program can run on any LSB distro instead of just the
> host.
> 
> LSB provide a compiler wrapper for the host C and C++ compilers called
> 'lsbcc' and 'lsbc++'.  The wrapper checks the executable name to figure
> out if you're calling the C or C++ compiler so you have to call these
> names exactly.
> 
> Caveats: You need a 4.1 or 4.2 compiler to build.  Various parts of
> the toolchain don't compile LSB 3.0+ header files.  Some parts
> accidentally use the host include files.  A patch that works around
> these is at:
>  http://people.linaro.org/~michaelh/keep/00-crosstool-lsb-hacks.patch
> 
> Nits: I'm abusing the case statement to do an AND but it makes the
> default value cleaner.
> 
> Signed-off-by: Michael Hope <michael.hope@linaro.org>
> 
> diff -r 49af7802dcd5 -r edadd06cb17f config/toolchain.in
> --- a/config/toolchain.in	Tue Nov 22 10:08:10 2011 +0100
> +++ b/config/toolchain.in	Mon Nov 28 12:56:25 2011 +1300
> @@ -247,6 +247,18 @@
>        for that by checking the tools without the suffix in case it can
>        not find some of the tool.
>  
> +config BUILD_USE_LSBCC
> +    bool
> +    prompt "|  Build using the Linux Standard Base compilers"
> +    help
> +      Set to use the LSB C and C++ compiler wrappers lsbcc and
> +      lsbc++ instead of gcc and g++.
> +
> +      LSB applications are more portable and should run on any LSB
> +      compliant Linux based operating system.  Note that building
> +      against a LSB 3.0 system may require a pre-4.3 version of GCC

That sounds like a test should be made at runtime to check that the
available gcc is the correct version.

> +      and local patches to the LSB build tree.

And this sounds like a show-stopper. This would require that the user does
patch his/her system, and that's definitely not something we want to
impose on him/her. :-(

>  if CANADIAN
>  
>  comment "Host system"
> diff -r 49af7802dcd5 -r edadd06cb17f scripts/crosstool-NG.sh.in
> --- a/scripts/crosstool-NG.sh.in	Tue Nov 22 10:08:10 2011 +0100
> +++ b/scripts/crosstool-NG.sh.in	Mon Nov 28 12:56:25 2011 +1300
> @@ -390,6 +390,13 @@
>          fi
>  
>          for tool in ar as dlltool gcc g++ gcj gnatbind gnatmake ld nm objcopy objdump ranlib strip windres; do
> +            # Re-map GCC and G++ to the corresponding LSB names
> +            case "${CT_BUILD_USE_LSBCC},${m},${tool}" in
> +                y,BUILD,gcc)  target="lsbcc";;
> +                y,BUILD,g++)  target="lsbc++";;
> +                *)            target="${tool}";;
> +            esac

(OK, I saw your second mail about s/BUILD/HOST/)
I don't like the 'target' variable name. Why don't you overload the existing
variable 'tool'?

>              # First try with prefix + suffix
>              # Then try with prefix only
>              # Then try with suffix only, but only for BUILD, and HOST iff REAL_BUILD == REAL_HOST
> @@ -397,17 +404,17 @@
>              # This is needed, because some tools have a prefix and
>              # a suffix (eg. gcc), while others may have only one,
>              # or even none (eg. binutils)
> -            where=$(CT_Which "${t}${tool}${!s}")
> -            [ -z "${where}" ] && where=$(CT_Which "${t}${tool}")
> +            where=$(CT_Which "${t}${target}${!s}")
> +            [ -z "${where}" ] && where=$(CT_Which "${t}${target}")
>              if [    -z "${where}"                         \
>                   -a \(    "${m}" = "BUILD"                \
>                         -o "${CT_REAL_BUILD}" = "${!r}" \) ]; then
> -                where=$(CT_Which "${tool}${!s}")
> +                where=$(CT_Which "${target}${!s}")
>              fi
>              if [ -z "${where}"                            \
>                   -a \(    "${m}" = "BUILD"                \
>                         -o "${CT_REAL_BUILD}" = "${!r}" \) ]; then
> -                where=$(CT_Which "${tool}")
> +                where=$(CT_Which "${target}")
>              fi
>  
>              # Not all tools are available for all platforms, but some are really,

Otherwise, nothing to say. I'll have to look here how it behaves before I
can comment more.

Thank you!

Regards,
Yann E. MORIN.

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