https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104657
--- Comment #5 from Christoph Müllner <christophm30 at gmail dot com> ---
Creating hard-wired object references might be a solution, but there is a lot
of existing code out there, that would need to be patched (including all the
hassle with support for old and new compilers).
One example is the bootloader U-Boot, which does the following for ARM ([1]):
#define __arch_putl(v,a) (*(volatile unsigned int *)(a) = (v))
Another example is Linux, where read*()/write*() and friends do the following
([2]):
# define __iomem
void foo_linux(unsigned long v)
{
void __iomem *p = (void __iomem *)MEM_ADDR;
*(volatile unsigned long *)p = v;
}
FWIW, the __iomem expands in Linux as follows ([3]), if the sources are passed
to the semantic parser "sparse" ([4]):
# define __iomem __attribute__((noderef, address_space(__iomem)))
That's similar to the AVR solution but allows to create user-defined distinct
types.
[1]
https://source.denx.de/u-boot/u-boot/-/blob/master/arch/arm/include/asm/io.h#L50
[2]
https://elixir.bootlin.com/linux/latest/source/include/asm-generic/io.h#L125
[3]
https://elixir.bootlin.com/linux/latest/source/include/linux/compiler_types.h#L11
[4]
https://git.kernel.org/pub/scm/devel/sparse/sparse.git/tree/Documentation/annotations.rst
