On Tue, Jan 22, 2019 at 4:50 PM Miquel Raynal <miquel.raynal@xxxxxxxxxxx> wrote:
>
> Hi Masahiro,
>
> Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx> wrote on Tue, 22 Jan
> 2019 16:42:55 +0900:
>
> > Although drivers do not directly get access to the private data of
> > instruction patterns, let's use unnamed union field to be consistent
> > with nand_op_instr.
> >
>
> Actually this is how we wrote it the first time. Then we got robots
> reporting that anonymous unions where not allowed with older (still
> supported) GCC versions and I had to do this:
>
>
> commit c1a72e2dbb4abb90bd408480d7c48ba40cb799ce
> Author: Miquel Raynal <miquel.raynal@xxxxxxxxxxxxxxxxxx>
> Date: Fri Jan 19 19:11:27 2018 +0100
>
> mtd: nand: Fix build issues due to an anonymous union
>
> GCC-4.4.4 raises errors when assigning a parameter in an anonymous
> union, leading to this kind of failure:
>
> drivers/mtd/nand/marvell_nand.c:1936:
> warning: missing braces around initializer
> warning: (near initialization for '(anonymous)[1].<anonymous>')
> error: unknown field 'data' specified in initializer
> error: unknown field 'addr' specified in initializer
>
> Work around the situation by naming these unions.
>
> Fixes: 8878b126df76 ("mtd: nand: add ->exec_op() implementation")
> Reported-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxxxxxxxxx>
> Tested-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxxxxxxx>
>
Hmm, how come Andrew's compiler was fine with the following?
struct nand_flash_dev {
char *name;
union {
struct {
uint8_t mfr_id;
uint8_t dev_id;
};
uint8_t id[NAND_MAX_ID_LEN];
};
unsigned int pagesize;
...
};
The current minimum version is GCC 4.6
(commit cafa0010cd51fb7)
but I am not sure if this restriction is remaining.
--
Best Regards
Masahiro Yamada
