Re: RFC: Lose use of $ and . in [cd]tor labels

[Per Bothner <per at bothner dot com>]

Jason Merrill <jason@redhat.com> writes:

> Would it be appropriate to change the Java frontend to stop using '$' in
> names that get mangled?

Well, '$' can appears in the Java source, though it is recommended that
user code not use '$'.  However, .class files can be for classes whose
name (including file names) can contain with '$'.  So it is not enough
for jc1 to not "use" '$' - any incoming '$' also need to be mangled
somehow.

I think we should handle this similarly as other non-ascii names.  On
systems that can handle UTF8 in labels, we should also use '$'.  On
other systems, we should mangle both.  The no-dollar-in-label crock
should be revisited while we're considering how to handle non-ascii.

I think that on "GNU systems" (including those where
GNU binutils are the default):
(1) We should allow arbitrary UTF8 in binary files, including '$'.
(2) We should define an assembler quoting convention so that
any chararacter can be treated as an identifier character.

I.e. I would allow "99.9%" as an identifier in binary files.
In assembler files this could be written (using a Lisp convention):
        \9\9\.\9\%:
The assembler could assume that any byte that has the high-bit set
should be treated as a "letter" for the purpose of parsing labels
- i.e. it is implicitly preceded by '\\'.

For non-GNU systmem, we need to define a mangling that handles
'$' and non-ascii.
-- 
	--Per Bothner
per@bothner.com   http://www.bothner.com/~per/