The repair in 7176fc4253 did not make the no-discard decision stick
well enough for some cases. Robby found this bug using the Redex model
and random testing, too.
Using a parameter for the current expansion context means that if a
macro spawns a thread, the thread thinks that it's in an expansion
context. Switching to a raw continuation mark avoids that problem.
Along the way, bring Racket and RacketCS more in line by making both
have an internal notion of "root" prompt tag that can be used to get
all continuation marks independent of any prompts. That's not structly
necessary, since a continuation mark could be combined with a distinct
tag to make the mark always accessible, but it's simpler and more
lightweight to use a root prompt tag.
This improvement removes only a few places where a variable use is
considered possibly too early in the RacketCS implementation, but
the improvement is significant for uses of `input-port?` in "io".
Allow a single argument to comparison functions like `<`, and
support the same arities as the generic version for fixnum and
flonum operations like `fx+` or `fl+`.
RacketCS weak `equal?`-based hash tables didn't retain flonums, and
hashing of hash tables was not properly insensitive to the order of
keys.
Racket, meanwhile, didn't limit work consistently for different kinds
of hash tables, and it didn't keep a counter value odd as intended
(but the counter never gets large enough to appear to be a mapped
pointer, anyway).
Racket did not check for a break when escaping from a break-disabled
context to a break-enabled context. RacketCS didn't check in other
cases, either. Fix those various cases.
Commit 1afcbee381 effctively dropped a conditional case that was
marked as "shouldn't happen" --- but it does happen and makes sense.
Adjust the replacement `delete-directory/files` call to accomodate the
case.
Relevant to #2198 and #2236
Part of this change restores a `++direct` that was lost in 98ae91e0ba
for "racket/src/thread" to make the atomicity state a virtual
register. Also make `display` on a byte string more directly call
`write-bytes`. That change restores a 5-10% speed improvement for
`racketcs -cl racket/base`.
Change the expander-performance macro so that it's a very low cost if
not enabled on startup. An extra JIT specialization reduces the cost
further, since the enabled state is known by JIT time.
