Re: [PATCH v2 0/3] Inline helpers into Rust without full LTO

On Thu, Mar 26, 2026, at 16:18, Russell King (Oracle) wrote:
> On Thu, Mar 26, 2026 at 03:31:26PM +0100, Christian Schrefl wrote:
>> On 3/26/26 2:47 PM, Miguel Ojeda wrote:
>> > On Thu, Mar 26, 2026 at 11:10 AM Alice Ryhl <[email protected]> wrote:
>
> I'm not sure if this is still true, but I believe it used to be the case
> that the -linux-gnueabi target has one behaviour for enums (fixed size)
> whereas -none-eabi, the size of the type depends on the range of values
> included in the enum.

I checked Debian's arm-none-eabi-gcc, which indeed still has this behavior:

$ echo 'enum { A, B } x = sizeof(x);' | arm-none-eabi-gcc -xc - -O2 -o- -S | grep -A1 x:
x:
	.byte	1

and I see the same thing for the hexagon target in clang, but none
of the other targets that Linux runs on. In particular, clang always
behaves like linux-gnueabi even when targeting plain eabi.

$ echo 'enum { A, B } x = sizeof(x);' | clang --target=arm-none-eabi -xc - -O2 -o- -S | grep -A1 x:
x:
	.long	4

I noticed a similar issue with m68k-linux, which has a bitfield
alignment different from anything else on gcc, but uses the normal
behavior on clang.

        Arnd