[cfe-dev] naked attribute

[Reed Kotler]

With my x86 version of gcc, I get a warning if I use the naked attribute 
that it's not supported. I have 4.4.3

I don't get the warning with clang.

On 05/02/2013 05:20 PM, Reed Kotler wrote:
> On 05/02/2013 05:00 PM, Rafael Espíndola wrote:
>> On 2 May 2013 18:16, reed kotler
>> <rkotler-8NJIiSa5LzA-XMD5yJDbdMReXY1tMh2IBg at public.gmane.org> wrote:
>>> When I use the latest code sourcery/Menor release of the ARM compiler
>>> I get
>>> no return statement. This claims to be 4.6.3
>>>
>>
>> Lovely, so I guess this is architecture dependent. Any patch that
>> makes us more compatible with gcc in this area is welcome, so we need
>> to figure out which architectures get a ret and which ones get an
>> unreachable :-(
>>
>> Cheers,
>> Rafael
>>
>
> Not all architectures support the naked attribute, even in gcc.
> "Use this attribute on the ARM, AVR, MCORE, RX and SPU ports ..."
>
> gcc 4.7 in the android toolkit for arm does not emit a return statement.
>
> (building cross tool chains with gcc is a pain so that's why I at first
> just downloaded the gcc arm version from the mentor/code sourcery site).
>
> fu at fu-G10IL:~/dev/test$
> ~/dev/android-ndk-r8e/toolchains/arm-linux-androideabi-
> 4.7/prebuilt/linux-x86/bin/arm-linux-androideabi-gcc  -S tnaked.c
>
> fu at fu-G10IL:~/dev/test$ cat tnaked.s
>          .arch armv5te
>          .fpu softvfp
>          .eabi_attribute 20, 1
>          .eabi_attribute 21, 1
>          .eabi_attribute 23, 3
>          .eabi_attribute 24, 1
>          .eabi_attribute 25, 1
>          .eabi_attribute 26, 2
>          .eabi_attribute 30, 6
>          .eabi_attribute 34, 0
>          .eabi_attribute 18, 4
>          .file   "tnaked.c"
>          .text
>          .align  2
>          .global tnaked
>          .type   tnaked, %function
> tnaked:
>          @ Naked Function: prologue and epilogue provided by programmer.
>          @ args = 0, pretend = 0, frame = 0
>          @ frame_needed = 1, uses_anonymous_args = 0
>          .size   tnaked, .-tnaked
>          .align  2
>          .global tnonaked
>          .type   tnonaked, %function
> tnonaked:
>          @ args = 0, pretend = 0, frame = 0
>          @ frame_needed = 1, uses_anonymous_args = 0
>          @ link register save eliminated.
>          str     fp, [sp, #-4]!
>          add     fp, sp, #0
>          add     sp, fp, #0
>          ldmfd   sp!, {fp}
>          bx      lr
>          .size   tnonaked, .-tnonaked
>          .ident  "GCC: (GNU) 4.7"
>          .section        .note.GNU-stack,"",%progbits