[PATCH/AARCH64 6/6] Support ILP32 multi-lib

[Andrew Pinski]

On Mon, Dec 9, 2013 at 12:12 PM, Yufeng Zhang <Yufeng.Zhang@arm.com> wrote:
> On 12/03/13 21:24, Andrew Pinski wrote:
>>
>> Hi,
>>    This is the final patch which adds support for the dynamic linker and
>> multi-lib directories for ILP32.  I did not change multi-arch support as
>> I did not know what it should be changed to and internally here at Cavium,
>> we don't use multi-arch.
>>
>>
>> OK?  Build and tested for aarch64-linux-gnu with and without
>> --with-multilib-list=lp64,ilp32.
>>
>> Thanks,
>> Andrew Pinski
>>
>>
>>
>>         * config/aarch64/aarch64-linux.h (GLIBC_DYNAMIC_LINKER):
>> /lib/ld-linux32-aarch64.so.1
>>         is used for ILP32.
>>         (LINUX_TARGET_LINK_SPEC): Add linker script
>>          file whose name depends on -mabi= and -mbig-endian.
>>         * config/aarch64/t-aarch64-linux (MULTILIB_OSDIRNAMES): Handle
>> LP64 better
>>         and handle ilp32 too.
>>         (MULTILIB_OPTIONS): Delete.
>>         (MULTILIB_DIRNAMES): Delete.
>> ---
>>   gcc/ChangeLog                      |   11 +++++++++++
>>   gcc/config/aarch64/aarch64-linux.h |    5 +++--
>>   gcc/config/aarch64/t-aarch64-linux |    7 ++-----
>>   3 files changed, 16 insertions(+), 7 deletions(-)
>>
>> diff --git a/gcc/config/aarch64/aarch64-linux.h
>> b/gcc/config/aarch64/aarch64-linux.h
>> index 83efad4..408297a 100644
>> --- a/gcc/config/aarch64/aarch64-linux.h
>> +++ b/gcc/config/aarch64/aarch64-linux.h
>> @@ -21,7 +21,7 @@
>>   #ifndef GCC_AARCH64_LINUX_H
>>   #define GCC_AARCH64_LINUX_H
>>
>> -#define GLIBC_DYNAMIC_LINKER "/lib/ld-linux-aarch64.so.1"
>> +#define GLIBC_DYNAMIC_LINKER "/lib/ld-linux%{mabi=ilp32:32}-aarch64.so.1"
>
>
> To be more explicit and consistent, the name of the ILP32 loader shall have
> 'ilp32' instead of '32'.  The extension field shall be appended to
> 'aarch64', separated by '_', and we should probably add the big-endian name
> at the same time.  With the extension fields sorted alphabetically,
> GLIBC_DYNAMIC_LINKER can be defined as:
>
> "/lib/ld-linux-aarch64%{mbig-endian:_be}%{mabi=ilp32:_ilp32}.so.1"
>
> The multi-arch names shall follow the same naming convention (although we
> don't have to add the multi-arch support right now).

AS mentioned in another email I think _be is incorrect.  I also think
aarch64 becomes redundant for _ilp32 and really it should be just:
"/lib/ld-linux-%{mabi=ilp32:ilp32;:aarch64}.so.1"


>
>
>>
>>   #define CPP_SPEC "%{pthread:-D_REENTRANT}"
>>
>> @@ -32,7 +32,8 @@
>>      %{rdynamic:-export-dynamic}                        \
>>      -dynamic-linker " GNU_USER_DYNAMIC_LINKER "        \
>>      -X                                         \
>> -   %{mbig-endian:-EB} %{mlittle-endian:-EL}"
>> +   %{mbig-endian:-EB} %{mlittle-endian:-EL}    \
>> +   -maarch64linux%{mabi=ilp32:32}%{mbig-endian:b}"
>>
>>   #define LINK_SPEC LINUX_TARGET_LINK_SPEC
>>
>> diff --git a/gcc/config/aarch64/t-aarch64-linux
>> b/gcc/config/aarch64/t-aarch64-linux
>> index ca1525e..5032ea9 100644
>> --- a/gcc/config/aarch64/t-aarch64-linux
>> +++ b/gcc/config/aarch64/t-aarch64-linux
>> @@ -22,10 +22,7 @@ LIB1ASMSRC   = aarch64/lib1funcs.asm
>>   LIB1ASMFUNCS = _aarch64_sync_cache_range
>>
>>   AARCH_BE = $(if $(findstring TARGET_BIG_ENDIAN_DEFAULT=1,
>> $(tm_defines)),_be)
>> -MULTILIB_OSDIRNAMES = .=../lib64$(call
>> if_multiarch,:aarch64$(AARCH_BE)-linux-gnu)
>> +MULTILIB_OSDIRNAMES = mabi.lp64=../lib64$(call
>> if_multiarch,:aarch64$(AARCH_BE)-linux-gnu)
>>   MULTIARCH_DIRNAME = $(call if_multiarch,aarch64$(AARCH_BE)-linux-gnu)
>>
>> -# Disable the multilib for linux-gnu targets for the time being; focus
>> -# on the baremetal targets.
>> -MULTILIB_OPTIONS    =
>> -MULTILIB_DIRNAMES   =
>> +MULTILIB_OSDIRNAMES += mabi.ilp32=../lib32
>
>
> Similarly, we shall use libilp32 for the OSDIRNAME.  Although a bit ugly,
> libilp32 is much less ambiguous than lib32; the latter is easily confused
> with a directory for aarch32 libs.

There is no ambiguous between lib and lib32.  This is exactly what is
used for MIPS where lib32 is n32 and lib is o32 (and lib64 is for
n64).  I think we should follow what is done there as it is already
done and having ilp in every directory name is a bit overkill (and
maybe even worse for most libtool based items where lib32 already is
part of it).

I rather have seen this level of detail from ARM when I had asked for
the Linux ILP32 ABI but we (Cavium) never got this so we decided to go
and implement this ourselves.

Thanks,
Andrew Pinski

>
> Thanks,
> Yufeng
>