Re: PATCH: gdb --args

[Tom Tromey <tromey at redhat dot com>]

>>>>> "Andrew" == Andrew Cagney <ac131313@cygnus.com> writes:

Andrew> Check corrina's recent patch to add in_function_epilogue_p().
Andrew> It included a default case that did what 99% of targets
Andrew> wanted.  Here 99% of targets would be everything except DJGPP
Andrew> and (possibly) cygwin.

Many or most of the remote targets don't accept arguments at all.
Maybe having a Unix-like default for these is ok though?

>> If I'm reading the source correctly, right now with a PPC Linux gdb
>> the user can use `target sim'.  This changes how the quoted argument
>> will be decomposed -- instead of using sh-style dequoting, instead the
>> `buildargv()' function from libiberty will be used.  But as far as I
>> can tell, typing `target sim' doesn't change anything in the current
>> gdbarch.  All it seems to change is the current target vector.

Andrew> Sorry I'm lost here.  buildargv() takes a string and both
Andrew> dequotes and splits it.  It is a very primative implementation
Andrew> of SH's argument parser - it is trying to emulate the behavour
Andrew> the user sees when running ``powerpc-elf-run arg arg arg
Andrew> arg''.  If the architecture fuction correctly transforms argv
Andrew> into a string then buildargv() should manage to transform it
Andrew> back into an argv list.

buildargv() splits the string one way.  fork-child.c splits it a
different way -- the /bin/sh way.  If STARTUP_WITH_SHELL is 0, then
fork-child.c uses a completely different dequoting method --
breakup_args().

If the user changes the target with `target sim', then the dequoting
rules change without any corresponding change to current_gdbarch.  So
if the quoting method is in current_gdbarch, it will continue to use a
fixed, and possibly inappropriate, quoting method.

Suppose for instance that STARTUP_WITH_SHELL is 0.  In this case
spaces in command-line arguments are simply invalid.  So an invocation
like:

    gdb --args foo "space in arg"

is invalid.  If the user types `show args' he'll get an error with my
current patch.

However, if the user type `target sim' and then `show args', it ought
to work.  But if the quoting function is in gdbarch, I don't see how
it can.  `target sim' has no effect on current_gdbarch, as far as I
can see.

Tom