Messages in this thread | | | Date | Wed, 15 Oct 2014 13:01:02 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH 2/3] checkpatch: Add error on use of attribute((weak)) or __weak |
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On Wed, 15 Oct 2014 12:52:44 -0700 Joe Perches <joe@perches.com> wrote:
> On Wed, 2014-10-15 at 12:50 -0700, Andrew Morton wrote: > > On Wed, 15 Oct 2014 12:45:48 -0700 Joe Perches <joe@perches.com> wrote: > > > > > On Wed, 2014-10-15 at 12:42 -0700, Andrew Morton wrote: > > > > On Wed, 15 Oct 2014 12:32:08 -0700 Joe Perches <joe@perches.com> wrote: > > > > > > > > > Using weak can have unintended link defects. > > > > > Emit an error on its use. > > > > > > > > Well, we don't want a warning about use of __weak in function > > > > definitions. Only in declarations. > > > > > > Why is that? > > > > Because the problem we're trying to detect is when __weak is used on a > > declaration. > > > > This is OK: > > > > foo.h: > > extern int foo(void); > > foo.c: > > int __weak foo(void) > > { > > ... > > } > > > > But this is not OK: > > > > foo.h: > > extern __weak int foo(void); > > foo.c: > > int __weak foo(void) > > { > > ... > > } > > > > And this? > > foo.c: > > extern __weak int foo(void); > > int __weak foo(void) > { > } >
That's why I just said "And this bit maybe is checking for use in a header file, which is not as good as checking for a declaration but is probably good enough."
I don't think that would trigger the bug anyway. The problem is that
extern __weak int foo(void);
int foo(void) { }
unexpectedly and undesirably turns foo() into __weak.
I think it would be sufficient to check for __weak in a declaration. If that isn't practical then checking for __weak in a .h file should suffice.
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