On Mon, Dec 28, 2020 at 04:28:24PM +0000, Ramsay Jones wrote:
>
>
> On 26/12/2020 17:51, Luc Van Oostenryck wrote:
> > Currently, packed bitfields are not handled correctly.
> >
> > Add some testcases for them.
> >
> > Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@xxxxxxxxx>
> > ---
> > validation/packed-bitfield0.c | 67 +++++++++++++++++++++++++++++++++++
> > validation/packed-bitfield1.c | 28 +++++++++++++++
> > validation/packed-bitfield2.c | 16 +++++++++
> > validation/packed-bitfield3.c | 29 +++++++++++++++
> > validation/packed-bitfield4.c | 19 ++++++++++
> > validation/packed-bitfield5.c | 21 +++++++++++
> > 6 files changed, 180 insertions(+)
> > create mode 100644 validation/packed-bitfield0.c
> > create mode 100644 validation/packed-bitfield1.c
> > create mode 100644 validation/packed-bitfield2.c
> > create mode 100644 validation/packed-bitfield3.c
> > create mode 100644 validation/packed-bitfield4.c
> > create mode 100644 validation/packed-bitfield5.c
> >
> > diff --git a/validation/packed-bitfield0.c b/validation/packed-bitfield0.c
> > new file mode 100644
> > index 000000000000..907500dedbf0
> > --- /dev/null
> > +++ b/validation/packed-bitfield0.c
> > @@ -0,0 +1,67 @@
> > +#define alignof(X) __alignof__(X)
> > +#define __packed __attribute__((packed))
> > +
> > +struct sa {
> > + int a:7;
> > + int c:10;
> > + int b:2;
> > +} __packed;
> > +_Static_assert(alignof(struct sa) == 1, "alignof(struct sa)");
> > +_Static_assert( sizeof(struct sa) == 3, "sizeof(struct sa)");
> > +
> > +struct __packed sb {
> > + int a:7;
> > + int c:10;
> > + int b:2;
> > +};
> > +_Static_assert(alignof(struct sb) == 1, "alignof(struct sb)");
> > +_Static_assert( sizeof(struct sb) == 3, "sizeof(struct sb)");
>
> Why 'struct sb'? It is not used in the rest of the test (and is
> identical to 'struct sa').
Good question :)
I've probably reused some previous file as a kind of template.
> > diff --git a/validation/packed-bitfield3.c b/validation/packed-bitfield3.c
> > new file mode 100644
> > index 000000000000..6acff875299f
> > --- /dev/null
> > +++ b/validation/packed-bitfield3.c
> > @@ -0,0 +1,29 @@
> > +#define __packed __attribute__((packed))
> > +
> > +typedef unsigned char u8;
> > +typedef __UINT16_TYPE__ u16;
> > +typedef __UINT32_TYPE__ u32;
> > +typedef __UINT64_TYPE__ u64;
> > +
> > +struct b {
> > + u32 a:1;
> > + u32 b:2;
> > + u32 c:4;
> > + u32 d:8;
> > + u32 e:16;
> > +} __packed;
> > +_Static_assert(__alignof(struct b) == 1);
> > +_Static_assert( sizeof(struct b) == sizeof(u32));
>
> Again '== sizeof(u32)' does not seem useful. (what is it
> trying to say?)
>
> > +
> > +struct c {
> > + u8 a;
> > + u8 b;
> > + u64 c:48;
> > +} __packed;
> > +_Static_assert(__alignof(struct c) == 1);
> > +_Static_assert( sizeof(struct c) == sizeof(u64));
>
> ditto.
Yes, I agree.
-- Luc
