Re: [PATCH, i386, Android] -mandroid support for i386 target

[Ilya Enkovich <enkovich dot gnu at gmail dot com>]

> On 2/04/2012, at 3:23 AM, Ilya Enkovich wrote:
>
>>> As is, it appears this patch did not see much testing, I'm pretty sure it breaks building shared libraries and PIE executable for Linux.
>>
>> I do not expect any changes in compiler behavior for non Android
>> targets. I bootstrapped and checked patched compiler on linux-x86_64.
>> I also built ptched compiler for Android target using NDK scripts.
>
> OK.
>
>>>
>>> Here and in other instances below you use "GNU_USER_TARGET_" prefix. ?I would prefer using a shorter "GNU_USER_" instead unless there is a good reason to add "TARGET" too.
>>
>> The reason is that some macroses are defined in other files and I just
>> redefine them (i.e. GNU_USER_TARGET_CC1_SPEC). This prefix is also
>> used for other targets (i.e. in linux-eabi.h). So I do not see a good
>> reason to change it everywhere or mix it with other prefix
>> "GNU_USER_".
>
> OK.
>
>>> Here you remove "%{shared|pie:crtendS.o%s;:crtend.o%s} crtn.o%s". ?Presumably, you are moving that to GNU_USER[_TARGET]_ENDFILE_SPEC, but you never define it.
>>
>> You are right. It is in GNU_USER_TARGET_ENDFILE_SPEC which is defined
>> in gcc/config/gnu-user.h.
>
> OK. ?I missed that GNU_USER_TARGET_ENDFILE_SPEC was already defined.
>
>>
>>>
>>>>
>>>> /* A C statement (sans semicolon) to output to the stdio stream
>>>> ? ?FILE the assembler definition of uninitialized global DECL named
>>>> diff --git a/gcc/config/i386/linux.h b/gcc/config/i386/linux.h
>>>> index 73681fe..a832ddc 100644
>>>> --- a/gcc/config/i386/linux.h
>>>> +++ b/gcc/config/i386/linux.h
>>>
>>> i386/linux.h is used only for simple x86 32-bit builds; i386/linux64.h is used for multilib-enabled x86 toolchains. ?Placing below definitions in i386/linux.h will not allow adding an Android as an additional multilib to -m32/-m64 x86 builds. ?I improve on this situation I suggest:
>>> - rename i386/linux.h to i386/linux32.h (with corresponding change to config.gcc),
>>> - put below definitions to new i386/linux.h (remember to add license notice header to the new file),
>>> - include i386/linux.h from both i386/linux32.h and i386/linux64.h.
>>
>> Android does not support x86_64 target and therefore I do not want
>> -mandroid support for this target. When Android supports x86_64 target
>> this change would be appropriate.
>
> The point is that one can build a toolchain for i686-linux-gnu that will support both 32-bit and 64-bit multilibs. ?The 32-bit multilib will be used by default, and compilation for 64-bit user-space can be requested with -m64 option. ?Even though Android is not supported for -m64, such a toolchain can support Android as a additional "-m32 -mandroid" multilib. ?I.e., the toolchain will have three multilibs in total: "-m32" (default), "-m64" and "-m32 -mandroid". ?I386/linux64.h will be picked up for such a toolchain, even though by default it would compile for 32-bit target. ?Does this clear up things?
>

I think I see your point. And it seems to make all this work I'll also
have to rename i386/gnu-user.h into i386/gnu-user32.h and create
i386/gnu-user.h with common definitions to be included by
gnu-user[32|64].h. Otherwise I wont be able to use some definitions
(i.e. GNU_USER_TARGET_LINK_SPEC and GNU_USER_TARGET_MATHFILE_SPEC) in
linux64.h. Right?

Thanks,
Ilya

> Thank you,
>
> --
> Maxim Kuvyrkov
> CodeSourcery / Mentor Graphics
>