[PATCH] allow empty string as argument to -Map

[Rasmus Villemoes]

On 27/05/2020 18.50, Nick Clifton wrote:
> Hi Rasmus,
> 
>> So, as the next best thing, use a previously bogus value (the empty
>> string) as a sentinel to indicate "use the output filename + .map".
> 
> Thanks for suggesting this patch.  I have applied it along with a couple
> of changes:
> 
>   * If a filename is supplied, but it references a directory, then
>     create a file inside that directory, again based upon the output
>     filename with .map appended.  (I actually did this to make it
>     easier to test the new feature, but it strikes that it might be
>     useful in its own right).

That makes a lot of sense, thanks. And one can get "my" behaviour by
passing "-Map=." or "-Map .", which...

>   * Updated the --help output from the linker to show that the
>     filename is optional.

... eliminates the somewhat clumsy need to specify the empty string as
argument, either via -Map=  or actually have the shell insert an empty
string, -Map ''. I actually did attempt to modify the help text, but as
the argument isn't really optional, I couldn't find a way to indicate
that the empty string was meaningful - I worry a bit that the current

  -Map [FILE]         Write a map file (default: <outputname>.map)

can lead people to think that one can actually omit the argument - and

  -Map --gc-sections

would just put the map in the file --gc-sections, but otherwise work.

So before this gets set in stone, can I retract my suggestion of
assigning meaning to the empty string (maybe continue to handle it
internally equivalent to ".", but not advertising it)? For the help
text, it's hard to explain in one line, but perhaps something like

  -Map FILE/DIR     Write a map file to FILE or DIR/<outputname>.map

(And perhaps change "map file" to "link map" or "linker map")

Rasmus