Re: [PATCH] arm64: traps: Mark __le16, __le32, __user variables properly

From: Will Deacon
Date: Tue Feb 21 2017 - 06:04:04 EST

On Mon, Feb 20, 2017 at 10:33:45PM +0100, Luc Van Oostenryck wrote:
> I just checked this and I'm not very sure what's best.
> Sparse is very well aware of the '...' to specify a range
> in an array initializer or in switch-case. The warning
> is there only because those entries are later overridden
> with some value.
> When checking what GCC is doing in this situation is saw
> that by default even in cases like:
> static in ref[] = {
> [1] = 1,
> [2] = 2,
> };
> GCC doesn't issue a warning. You need to use the flag
> -Woverride-init for that. But then you also have a warning
> for our current case:
> static in foo[] = {
> [0 ... 3] = 1,
> [0] = 2,
> };
> It's easy enough to patch sparse to not issue a warning when the
> override concerns a range (which would be perfect for the situation here),
> Controlled or not by a new warning flag. But I'm far from convinced
> that all uses of such "ranged-initialization" is used for default values
> that may be later overridden.

How about not warning only when the overridden range covers the entire
length of the array? The only broken case I can think of that slips
through the cracks then is if somebody typoed the range so that it
accidentally covered the whole array and therefore suppressed the override