Messages in this thread | | | Date | Mon, 20 Jul 2020 16:02:52 -0500 | From | Segher Boessenkool <> | Subject | Re: [PATCH] powerpc/boot: Use address-of operator on section symbols |
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Hi!
On Sat, Jul 18, 2020 at 09:50:50AM +0200, Geert Uytterhoeven wrote: > On Wed, Jun 24, 2020 at 6:02 AM Nathan Chancellor > <natechancellor@gmail.com> wrote: > > /* If we have an image attached to us, it overrides anything > > * supplied by the loader. */ > > - if (_initrd_end > _initrd_start) { > > + if (&_initrd_end > &_initrd_start) { > > Are you sure that fix is correct? > > extern char _initrd_start[]; > extern char _initrd_end[]; > extern char _esm_blob_start[]; > extern char _esm_blob_end[]; > > Of course the result of their comparison is a constant, as the addresses > are constant. If clangs warns about it, perhaps that warning should be moved > to W=1? > > But adding "&" is not correct, according to C.
Why not?
6.5.3.2/3 The unary & operator yields the address of its operand. [...] Otherwise, the result is a pointer to the object or function designated by its operand.
This is the same as using the name of an array without anything else, yes. It is a bit clearer if it would not be declared as array, perhaps, but it is correct just fine like this.
Segher
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