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SubjectRe: [PATCH v2 3/5] Creates macro to avoid variable shadowing
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Hi Leonardo,

On 10/22/18 11:10 PM, Leonardo Brás wrote:
> Creates DEF_FIELD_ADDR_VAR as a more generic version of the DEF_FIELD_ADD
> macro, allowing usage of a variable name other than the struct element name.
> Also, sets DEF_FIELD_ADDR as a specific usage of DEF_FILD_ADDR_VAR in which
> the var name is the same as the struct element name.
>
> Signed-off-by: Leonardo Brás <leobras.c@gmail.com>
> ---
> scripts/mod/file2alias.c | 24 +++++++++++++++++-------
> 1 file changed, 17 insertions(+), 7 deletions(-)
>
> diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c
> index 7be43697ff84..3015c0bdecb2 100644
> --- a/scripts/mod/file2alias.c
> +++ b/scripts/mod/file2alias.c
> @@ -95,12 +95,20 @@ extern struct devtable *__start___devtable[], *__stop___devtable[];
> */
> #define DEF_FIELD(m, devid, f) \
> typeof(((struct devid *)0)->f) f = TO_NATIVE(*(typeof(f) *)((m) + OFF_##devid##_##f))
> +
> +/* Define a variable v that holds the address of field f of struct devid
> + * based at address m. Due to the way typeof works, for a field of type
> + * T[N] the variable has type T(*)[N], _not_ T*.
> + */
> +#define DEF_FIELD_ADDR_VAR(m, devid, f, v) \
> + typeof(((struct devid *)0)->f) *v = ((m) + OFF_##devid##_##f)
> +
> /* Define a variable f that holds the address of field f of struct devid
> * based at address m. Due to the way typeof works, for a field of type
> * T[N] the variable has type T(*)[N], _not_ T*.
> */
> #define DEF_FIELD_ADDR(m, devid, f) \
> - typeof(((struct devid *)0)->f) *f = ((m) + OFF_##devid##_##f)
> + DEF_FIELD_ADDR_VAR(m, devid, f, f)
>
> /* Add a table entry. We test function type matches while we're here. */
> #define ADD_TO_DEVTABLE(device_id, type, function) \
> @@ -641,25 +649,27 @@ static void do_pnp_card_entries(void *symval, unsigned long size,
> unsigned int i;
>
> device_id_check(mod->name, "pnp", size, id_size, symval);
> + DEF_FIELD_ADDR(symval, pnp_card_device_id, devs);
> + typeof(devs) devs_last;
>
> for (i = 0; i < count; i++) {
> unsigned int j;
> - DEF_FIELD_ADDR(symval + i*id_size, pnp_card_device_id, devs);
> + devs_last = devs + i * id_size;

Instead of doing all these changes, you could just modify here with
DEF_FIELD_ADDR_VAR(symval + i*id_size, pnp_card_device_id, devs,
devs_aux);

Like this you are not changing the logic in this file, you are just
renaming the variable which is more then enough to solve the -Wshadow
warning.
I don't it is worthy changing the logic.

Regards,
Helen.

>
> for (j = 0; j < PNP_MAX_DEVICES; j++) {
> - const char *id = (char *)(*devs)[j].id;
> - int i2, j2;
> + const char *id = (char *)(*devs_last)[j].id;
> + int j2;
> int dup = 0;
>
> if (!id[0])
> break;
>
> /* find duplicate, already added value */
> - for (i2 = 0; i2 < i && !dup; i2++) {
> - DEF_FIELD_ADDR(symval + i2*id_size, pnp_card_device_id, devs);
> + while ((devs_last -= id_size) >= devs && !dup) {
>
> for (j2 = 0; j2 < PNP_MAX_DEVICES; j2++) {
> - const char *id2 = (char *)(*devs)[j2].id;
> + const char *id2 =
> + (char *)(*devs_last)[j2].id;
>
> if (!id2[0])
> break;
>

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