Track fixnum results in the same way as flonum results to enable
unboxing, if that turns out to be useful. The intent of the change,
though, is to support other types in the future, such as "extnums".
The output `raco decompile' no longer includes `#%in', `#%flonum',
etc., annotations, which are mostly obvious and difficult to
keep in sync with the implementation. A local-binding name now
reflects a known type, however.
The change includes a bug repair for he bytecode compiler that
is independent of the generalization (i.e., the new test case
triggered the old problem using flonums).
Shape information allows the linker to check the importing
module's compile-time expectation against the run-time
value of its imports. The JIT, in turn, can rely on that
checking to better inline structure-type predicates, etc.,
and to more directy call JIT-generated code across
module boundaries.
In addition to checking the "shape" of an import, the import's
JITted vs. non-JITted state must be consistent. To prevent shifts
in JIT state, the `eval-jit-enabled' parameter is now restricted
in its effect to top-level bindings.
Bytecode changes in two small ways to help the validator:
* a cross-module variable reference preserves the compiler's
annotation on whether the reference is constant, fixed, or other
* lifted procedures now appear in the module body just before the
definitions that use them, instead of at the beginning of the
module body
Inline only trivial functions, such as `(empty? x)' -> `(null? x)',
to avoid generating too much code.
Bytecode includes a new `inline-variant' form, which records a
version of a function that is suitable for cross-module inlining.
Mostly, the variant let the run-time system to retain a copy
of the bytecode while JITting (and dropping the bytecode of)
the main variant, but it may be different from the main variant
in other ways that make it better for inlining (such a less loop
unrolling).
The JIT and bytecode compiler disagreed on the definition of
"constant". Now there are two levels: "constant" means constant across
all instantiations, and "fixed" means constant for a given instantation.
The JIT uses this distinction to generate direct-primitive calls
or not. (Without the distinction, a direct jump to `reverse' could
be wrong, because `racket/base' might get instantiated with the
JIT disabled or not.)
Also, fixed a bug in the JIT's `vector-set!' code in the case that
the target vector is a top-/module-level reference that is ready,
fixed, or constant.
