If I want to cross-compile with LDC, the host being OS X and the target being Linux 64bit. What would be the easiest way, can I use the tools from ELLCC [1]?

Can I specify the linker in LDC or do I need to separately link?

[1] http://ellcc.org

-- 
/Jacob Carlborg

On Thursday, 18 February 2016 at 21:11:52 UTC, Jacob Carlborg wrote:
> If I want to cross-compile with LDC, the host being OS X and the target being Linux 64bit. What would be the easiest way, can I use the tools from ELLCC [1]?
>
> Can I specify the linker in LDC or do I need to separately link?
>
> [1] http://ellcc.org

Search back and Kai wrote a post on cross compiling to arm64.  I cross compile to iOS but using the iPhone sdk is a different process than what I think you want.

Dan

On Thursday, 18 February 2016 at 21:11:52 UTC, Jacob Carlborg wrote:
> If I want to cross-compile with LDC, the host being OS X and the target being Linux 64bit. What would be the easiest way, can I use the tools from ELLCC [1]?
>
> Can I specify the linker in LDC or do I need to separately link?
>
> [1] http://ellcc.org

As in linux/AArch64?  There are two steps to cross-compiling with ldc:

1. Cross-compile druntime and phobos for the OS/arch combo you want.  This is easy to do using the cmake build scripts that come with the ldc source, assuming ldc, druntime and phobos already support the platform you want.  Simply set D_FLAGS to the llvm triple and any other specific flags you need, as I do for Android/ARM (https://gist.github.com/joakim-noah/63693ead3aa62216e1d9#file-ldc_android_arm-L3131), and set CC to a C cross-compiler for your target platform (export CC=/home/jacob/elcc-linux-aarch64/bin/clang), as there are a few C files and one asm file that druntime and phobos require.  You may also need to set RT_CFLAGS, depending on the C compiler for your platform (can be seen in the link below).

2. Specify a linker for your OS/arch when cross-compiling with ldc.  If you have a C compiler already configured to use that linker, as elcc might provide, all that requires is setting CC to that C compiler before running ldc, as shown above.  Otherwise, you can cross-compile to object files using ldc and the -c flag, then run your linker by hand, as I do with the Android NDK (https://gist.github.com/joakim-noah/63693ead3aa62216e1d9#file-ldc_android_arm-L3164).

On 2016-02-19 09:51, Joakim wrote:

> As in linux/AArch64?  There are two steps to cross-compiling with ldc:

No, as in Linux x86_64.

> 1. Cross-compile druntime and phobos for the OS/arch combo you want.
> This is easy to do using the cmake build scripts that come with the ldc
> source, assuming ldc, druntime and phobos already support the platform
> you want.  Simply set D_FLAGS to the llvm triple and any other specific
> flags you need, as I do for Android/ARM
> (https://gist.github.com/joakim-noah/63693ead3aa62216e1d9#file-ldc_android_arm-L3131),
> and set CC to a C cross-compiler for your target platform (export
> CC=/home/jacob/elcc-linux-aarch64/bin/clang), as there are a few C files
> and one asm file that druntime and phobos require.  You may also need to
> set RT_CFLAGS, depending on the C compiler for your platform (can be
> seen in the link below).

Since this is for Linux x86_64, could I just use the pre-compiled libraries from the Linux release?

What is RT_CFLAGS for?

> 2. Specify a linker for your OS/arch when cross-compiling with ldc.  If
> you have a C compiler already configured to use that linker, as elcc
> might provide, all that requires is setting CC to that C compiler before
> running ldc, as shown above.  Otherwise, you can cross-compile to object
> files using ldc and the -c flag, then run your linker by hand, as I do
> with the Android NDK
> (https://gist.github.com/joakim-noah/63693ead3aa62216e1d9#file-ldc_android_arm-L3164).

That seems pretty simple.

-- 
/Jacob Carlborg

On Friday, 19 February 2016 at 12:06:15 UTC, Jacob Carlborg wrote:
> What is RT_CFLAGS for?

They are the compile flags for the C parts of druntime/Phobos (zlib etc.).

On Friday, 19 February 2016 at 12:06:15 UTC, Jacob Carlborg wrote:
> On 2016-02-19 09:51, Joakim wrote:
>> 1. Cross-compile druntime and phobos for the OS/arch combo you want.
>> This is easy to do using the cmake build scripts that come with the ldc
>> source, assuming ldc, druntime and phobos already support the platform
>> you want.  Simply set D_FLAGS to the llvm triple and any other specific
>> flags you need, as I do for Android/ARM
>> (https://gist.github.com/joakim-noah/63693ead3aa62216e1d9#file-ldc_android_arm-L3131),
>> and set CC to a C cross-compiler for your target platform (export
>> CC=/home/jacob/elcc-linux-aarch64/bin/clang), as there are a few C files
>> and one asm file that druntime and phobos require.  You may also need to
>> set RT_CFLAGS, depending on the C compiler for your platform (can be
>> seen in the link below).
>
> Since this is for Linux x86_64, could I just use the pre-compiled libraries from the Linux release?

Probably?  Ldc "should" produce the exact same output on another OS and be able to use a standard library compiled elsewhere, provided you use the same version of ldc and llvm.  I haven't actually tried it, to see if that theory works out in practice. ;)

> What is RT_CFLAGS for?

As kinke says, those are the flags passed to your C compiler when building the C parts of druntime and phobos.  An example can be seen in my second link above, when invoking the clang Android/ARM cross-compiler from the Android NDK.

On 2016-02-19 18:14, Joakim wrote:

> Probably?  Ldc "should" produce the exact same output on another OS and
> be able to use a standard library compiled elsewhere, provided you use
> the same version of ldc and llvm.  I haven't actually tried it, to see
> if that theory works out in practice. ;)

Thanks, I'll give it a try.

> As kinke says, those are the flags passed to your C compiler when
> building the C parts of druntime and phobos.  An example can be seen in
> my second link above, when invoking the clang Android/ARM cross-compiler
> from the Android NDK.

Make sense now when I read the whole name :). Thanks.

-- 
/Jacob Carlborg

On Friday, 19 February 2016 at 01:11:52 UTC, Dan Olson wrote:
> On Thursday, 18 February 2016 at 21:11:52 UTC, Jacob Carlborg wrote:
>> If I want to cross-compile with LDC, the host being OS X and the target being Linux 64bit. What would be the easiest way, can I use the tools from ELLCC [1]?
>>
>> Can I specify the linker in LDC or do I need to separately link?
>>
>> [1] http://ellcc.org
>
> Search back and Kai wrote a post on cross compiling to arm64.  I cross compile to iOS but using the iPhone sdk is a different process than what I think you want.
>
> Dan

For reference: http://forum.dlang.org/post/fhwvxatxezkafnalwhqr@forum.dlang.org

Regards,
Kai

On 2016-02-20 19:08, Kai Nacke wrote:

> For reference:
> http://forum.dlang.org/post/fhwvxatxezkafnalwhqr@forum.dlang.org
>
> Regards,
> Kai

Thanks.

-- 
/Jacob Carlborg