2018-10-23 01:11:34

by Leonardo Brás

[permalink] [raw]
Subject: [PATCH v2 3/5] Creates macro to avoid variable shadowing

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 <[email protected]>
---
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;

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;
--
2.19.1



2018-10-23 21:17:05

by Helen Koike

[permalink] [raw]
Subject: Re: [PATCH v2 3/5] Creates macro to avoid variable shadowing

Hi Leonardo,

Thanks for your patch.

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 <[email protected]>
> ---
> 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)

You created this macro but you don't use it below, maybe you forgot to
update the patch? Please check.

Helen

> +
> /* 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;
>
> 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;
>

2018-10-23 21:36:48

by Helen Koike

[permalink] [raw]
Subject: Re: [PATCH v2 3/5] Creates macro to avoid variable shadowing

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 <[email protected]>
> ---
> 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;
>

2018-10-24 02:54:57

by Leonardo Brás

[permalink] [raw]
Subject: Re: [PATCH v2 3/5] Creates macro to avoid variable shadowing

Hello Helen,
On Tue, Oct 23, 2018 at 6:35 PM Helen Koike <[email protected]> wrote:
> 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.

You are right, that was what the patch was supposed to do. For some
crazy reason I must have submitted the wrong commit as a patch.

I will fix it and send you all a v3 ASAP.

Sorry for the inconvenience.
Thanks!

Leonardo Brás

2018-10-28 16:52:25

by Masahiro Yamada

[permalink] [raw]
Subject: Re: [PATCH v2 3/5] Creates macro to avoid variable shadowing

On Tue, Oct 23, 2018 at 10:11 AM Leonardo Brás <[email protected]> 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 <[email protected]>
> ---


Applied to linux-kbuild.



> 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;
>
> 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;
> --
> 2.19.1
>


--
Best Regards
Masahiro Yamada

2018-10-30 00:34:20

by Leonardo Brás

[permalink] [raw]
Subject: Re: [PATCH v2 3/5] Creates macro to avoid variable shadowing

Thank you!
On Sun, Oct 28, 2018 at 1:38 PM Masahiro Yamada
<[email protected]> wrote:
>
> On Tue, Oct 23, 2018 at 10:11 AM Leonardo Brás <[email protected]> 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 <[email protected]>
> > ---
>
>
> Applied to linux-kbuild.
>
>
>
> > 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;
> >
> > 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;
> > --
> > 2.19.1
> >
>
>
> --
> Best Regards
> Masahiro Yamada