Hi,

I tried to add support AArch64 XCODE5 about three months ago, too. I had the 
same compatibility issue in the other code. I just ended up adding ugly #ifdef 
as a workaround [1]. I think there are other compatibility issues in the 
current EDK2 code base. I’m not sure if the GAS macro and Apple Clang Assembler 
are compatible, but the C standard guarantees C preprocessor macro 
compatibility.

[1] 
https://github.com/retrage/edk2/commit/89b166758b9f858373bb20eb8e006914f7f13373

Best regards,

Akira Moroo

> On Jan 6, 2022, at 8:31, Pedro Falcato <[email protected]> wrote:
> 
> Hi,
> 
> GNU Assembler and the clang assembler support more complex macros natively 
> (using the .macro and.endm directives), without the need for the C 
> preprocessor.
> This completely sidesteps the need for explicit ";" as the GAS macros respect 
> newlines inside the macro.
> 
> See https://godbolt.org/z/6zzqoeKE4 for a very simple example.
> Of course, you can also pass arguments, see 
> https://sourceware.org/binutils/docs/as/Macro.html for the full documentation.
> 
> Best regards,
> Pedro
> 
> On Wed, Jan 5, 2022 at 8:36 PM Andrew Fish via groups.io 
> <[email protected]> wrote:
> I was playing around with getting Xcode to compile AArch64 code and I hit an 
> interesting compatibility issue. The assembler line continuation token for 
> GCC (;) is a comment for the Xcode clang assembler. For Xcode clang you need 
> to use %%. Yikes [1]
> 
> I was wondering if any one else has hit this in another project and if there 
> was any cool workaround?
> 
> The only thing I can think of is the “big hammer” on both (well you only need 
> one) ends. We could replace ; with a #define that matches the assembler. It 
> looks like this issue mostly hits in Code that is using C pre-processor 
> macros so we could refactor the code. I’m a little concerned that the C pre 
> processor is getting used since the macro languages of the assembler might 
> also have some compatibility issues?
> 
> Looking for ideas and opinions on the best way to fix this if we want to add 
> Xcode as an ARM compiler in the future. 
> 
> 
> [1] 
> https://github.com/tianocore/edk2/blob/master/MdePkg/Library/BaseLib/AArch64/SetJumpLongJump.S#L13
> 
> #define GPR_LAYOUT                         \
>         REG_PAIR (x19, x20,  0);           \
>         REG_PAIR (x21, x22, 16);           \
>         REG_PAIR (x23, x24, 32);           \
>         REG_PAIR (x25, x26, 48);           \
>         REG_PAIR (x27, x28, 64);           \
>         REG_PAIR (x29, x30, 80);/*FP, LR*/ \
>         REG_ONE  (x16,      96) /*IP0*/
> 
> I had to change it to:
> 
> #define GPR_LAYOUT                         \
>         REG_PAIR (x19, x20,  0)%%          \
>         REG_PAIR (x21, x22, 16)%%          \
>         REG_PAIR (x23, x24, 32)%%          \
>         REG_PAIR (x25, x26, 48)%%          \
>         REG_PAIR (x27, x28, 64)%%          \
>         REG_PAIR (x29, x30, 80)%%/*FP, LR*/ \
>         REG_ONE  (x16,      96) /*IP0*/
> 
> Thanks,
> 
> Andrew Fish
> 
> 
> 
> 
> 
> -- 
> Pedro Falcato
> 



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