Re: [PATCH, driver] -Wl, passing empty strings to ld

[Jim Wilson <wilson at codesourcery dot com>]

On Fri, 2010-04-16 at 17:46 +0200, Jakub Jelinek wrote:
> I think we should keep -Wl, as is and instead change the linker not
> to give so confusing error message (for empty filename add quotes
> around it or add them around always).

This was my next option to try, but it doesn't directly address the
problem.  How is the user supposed to realize that a mis-typed -Wl,
option is responsible for the empty filename?  There is no way for the
user to make that connection without help.  In an industrial
environment, where you can easily have a linker command over 1KB in
length, this makes finding the problem hard.

But there is a way to solve the problem.  The linker could do something
like this when it sees an empty filename on the command line:

khazaddum$ gcc -Wl, --whole-archive tmp.o
/usr/bin/ld: : No such file: No such file or directory
/usr/bin/ld: (empty filename, perhaps a mis-typed -Wl, gcc option)
collect2: ld returned 1 exit status
khazaddum$ 

The C++ front end does this in a few places, for instance, where it
emits an otherwise confusing error message.  I don't know if this is
done anywhere else offhand.  Obivously, I'd prefer a gcc solution, but I
could accept this linker solution.

FYI I tried a google search for an exact match on the phrase
"/usr/bin/ld: : No such file: No such file or directory".  I found 3 not
counting my gcc-patches thread.  One in English got no answer.  One in
English got only incorrect answers.  And one in Russian got a correct
answer, but it took an hour to find the bug in a fairly trivial command
line.  The second one in English in the most interesting one.  It has a
link command that is 2381 bytes long, 4 people contributed to the
thread, and none could find the bug over an almost 2 month period.  The
question is still unanswered as of today.
http://forums.oracle.com/forums/thread.jspa?threadID=1026800&tstart=0
I took pity on them and registered so I could give them an answer.

Jim