Re: [XEN PATCH v4 14/18] xen,symbols: rework file symbols selection

[Jan Beulich <jbeulich@xxxxxxxx>]

On 31.03.2020 12:30, Anthony PERARD wrote:
> We want to use the same rune to build mm/*/guest_*.o as the one use to
> build every other *.o object. The consequence it that file symbols that
> the program ./symbols prefer changes with CONFIG_ENFORCE_UNIQUE_SYMBOLS=y.
> 
> (1) Currently we have those two file symbols:
>     guest_walk.c
>     guest_walk_2.o
> (2) with CONFIG_ENFORCE_UNIQUE_SYMBOLS used on guest_walk.c, we will have:
>     arch/x86/mm/guest_walk.c
>     guest_walk_2.o
> 
> The order in which those symbols are present may be different.
> 
> Currently, in case (1) ./symbols chooses the *.o symbol (object file
> name). But in case (2), may choose the *.c symbol (source file name with
> path component) if it is first
> 
> We want to have ./symbols choose the object file name symbol in both
> cases.

I guess the reason for wanting this is somehow connected to the
statement at the beginning of the description, but I can't seem
to be able to make the connection.

> So this patch changes that ./symbols prefer the "object file
> name" symbol over the "source file name with path component" symbols.
> 
> The new intended order of preference is:
>     - first object file name symbol
>     - first source file name with path components symbol
>     - last source file name without any path component symbol

Isn't this going to lead to ambiguities again when
CONFIG_ENFORCE_UNIQUE_SYMBOLS? Several object files (in different
dirs) are named the same, after all. Static symbols with the same
name in such objects would hence resolve to the same kallsyms
name.

Jan