Chez Scheme now supports a single-pass combination of `collect` and
`compute-size-increments`, which makes a GC with accounting about
twice as fast. Meanwhile, other GC improvements reduce non-accounting
full-collection times by 10-20%.
Much of the GC implementation is now generated from a "Parenthe-C"
description, so update the bootstrap process for that step.
This fixes a major issue in arm 32bits, detected by ubsan, where
conversion of type to milliseconds results in overflow.
```
rktio_time.c:92:21: runtime error: signed integer overflow: 1584975753 * 1000 cannot be represented in type 'long int'
```
GCC 9.3 things that `h2` might reach line 385 uninitialized.
```
./hash.c:385:14: warning: 'h2' may be used uninitialized in this function [-Wmaybe-uninitialized]
385 | h = (h + h2) & mask;
| ~~~^~~~~
```
A Chez Scheme garbage collection involves a rendezvous among threads
that are used to implement places and futures (and potentially other
things that create Chez-level threads). The thread that is used to
drive the garbage collection was not formerly specified, and callbacks
like the GC icon in DrRacket can only be run in the initial thread.
When a major collection was run in a non-initial thread, the callback
was simply skipped.
The Racket branch of Chez Scheme now drives a collection in the
initial thread whenever that thread is active. In Racket CS, the
initial thread can be inactive if it's waiting for external events,
and a place can meanwhile trigger a GC. Now, when the Racket CS GC
callback is called for a major collection in any thread other than the
initial one, it defers the major collection to an asynchornous
callback in the main thread (and meanwhile performs a minor
collection).
So, a major collection might now be delayed by just a little while if
the main thread is inactive, such as when it's waiting for external
events, but callbacks like the GC icon in DrRacket will be reliably
invoked for major collections.
It's still unclear what the specification of syntax->string regarding whitespace
before closing parens should be. The implementation also has not dealt with
the issue. This PR therefore removes whitespace before closing parens from
the tests.
Once the discussion at
https://github.com/racket/racket/issues/3071#issuecomment-601984438
has reached a conclusion and implemented, we can add these tests back.
The `call-in-continuation` function generalizes applying a
continuation to values by accepting a thunk that is called in the
restored continuation. In other words, insteda of having to use the
pattern
((call/cc (lambda (k)
.... (set! saved-k k) ...
(lambda ()
original-result))))
...
(saved-k (lambda () new-result))
The extra call and thunk on the capture side can be omitted:
(call/cc (lambda (k)
.... (set! saved-k k) ...
original-result))
...
(call-in-continuation saved-k (lambda () new-result))
At the Chez Scheme level, a `call-in-continuation` in tail position
within a function can avoid forming a closure for its second argument.
The `call-in-continuation` function at the Racket CS level doesn't yet
provide that benefit.
The `call-in-continuation` operation is called `continuation-slice` in
Feeley's "A Better API for First-Class Continuations".
Expansion of a procedure with keywords is quadratic due to generating
a nested sequence of `let`s, but speed it up by roughly a constant
factor by using a dintinct symbol for each nested layer.
Related to #3070
Using `call-in-continuation` to apply a thunk within a continuation
slightly simplifies and speeds up parts of the implementation of
delimited continuations.
The expansion of `struct` created far too much code to parameterize
`struct-field-index`, making expansion of a `struct` form with just
100 or 200 fields take a noticeably long time to expand.
PR #2678 unintentionally removed this attribute, but it was used
at least by "collections-lib" and "static-rename-lib".
cc @sorawee @lexi-lambda @jackfirth @rmculpepper
GitHub's CDN seems to have recently started returning the `Location` header for a redirect with a lowercase `l`, which breaks the redirect logic. The HTTP spec says that header names are case-insensitive, so we need to look for either version.
Make `register-process-global` check for byte strings, and avoid
retaining the byte string that it's given (in case that changes, for
example).
Closes#3053
Building glib-specific support into the main Racket executable is
unsatisfying, but it's consistent with Racket BC, and the alternative
is especially tedious to deal with places and namespaces and
allocation.
Combined with a schemify improvement that inlines imported predicates
to expose the record-type test to Chez Scheme, this chage enables
cptypes to prune useless inlined `wrapped-object` selector branches.
That improvement, in turn, reduces code size and redundant checks on
objects that have contracts.
When a `lambda` form is marked as a method (for arity error reporting)
through a property, translate that to a static flag on the procedure,
instead of a call to `procedure->method`.
The only way we have to attach static information is through the
procedure name, so the encoding already in place for "no name" and
"path-based name" is extended to support a method flag.
Since procedures have names that are attached more directly by the
schemify pass, remove simple `let-values` forms wrapping procedures.
This shortcut improves the result of the lifting pass in some cases.
Record types with unnamed fields can be significantly more compact,
excdeption in combination with the constrain the the fields all
contain Scheme objects. Saves 2% for DrRacket's initial footprint.
We had to give back some space savings to avoid potential problems
with allocating in the event callback and running out of stack
space[?] when passing an argument. We get to keep most of the
improvement though.
Fix a regression in 712494312a, and change other other two printers to
be more consistent for
#lang racket
(struct s () #:transparent)
(define a (s))
(pretty-print (list (cons a 0) (cons a 0)))
A regexp can match while having sub-patterns that are not used in
the match. In regexp-replace, the "insert" argument can refer to
these unused sub-matches. If a function is given for the "insert"
argument, it will receive these unused submatches as #f values.
If a string or byte-string is given, then any reference to an
unused sub-match (by means of a back-reference) is treated as the
empty string or byte-string.
Fixes#3032.
When logging GC debugging, a pecentage after the time for a GC reports
what fraction was extra steps after GCing proper, especially the extra
step of memory acounting when that is enabled.
Also, avoid Chez Scheme gensyms even more. Otherwise, using low-level
facilities like `dump-memory-stats` can force the unique name of a
gensym used for a structure type, which causes it to be permanent,
which could be exactly what you don't want when debugging a
memory-rentention problem.
In `compiler/private/mach-o` --- which is reachable via `racket` due
to being a dependency of `setup/dirs` --- delay the call to
`cross-system-library-subpath` until needed.
Fixes optimization for an expression like
(define (f x)
(lambda (y)
(letrec ([recursion (f x)])
(+ x y))))
by adjusting the inlining hueristic to support less inlining on a
second pass of `letrec` right-hand sides.
Closes#3027
Provide `vm-primitive` and `vm-eval` to regularize access to VM-level
primitives. Document some of the issues for interoperating across the
Racket and (Chez Scheme) VM layers.
The library could have been implemented with just `compile-linklet`
and `instantiate-linklet`, but using an underlying `primitive-lookup`
function is a little nicer.
Produce 0, -1, or out-of-memory for bignum shifts. For large fixnum
shifts, check memory limits.
The repairs are mostly for Racket CS, but traditional Racket
incorrectly reported out-of-memory for 0 shifted by a positive bignum.
A more compact representation for return points tends to reduce code
by about 10%. For DrRacket, that translates to a 5% decrease in
overall footprint.
Explain how to deal with the "racket-lib" that is normally included
with a source distribution, but that doesn't have dependencies
specific to Windows or Mac OS.
Since schemify adds its own checking for procedureness in an
application, always compile the application as unsafe at the Chez
Scheme level. This simple change saves about 5% in code size for
DrRacket, which is a 1-2% footprint saving overall.
