Currently, there are many places in rustc, where we use
with_freevars to iterate over freevars of a closure. The
problem with this is the argument to with_freevars is a
NodeId and this will get in the way of our eventual goal
of solving for issue (#53488), sub-issue (#56905)
Adding a map to TypeckTables to get the list of all the Upvars
given a closureID. This is help us get rid of the recurring
pattern in the codebase of iterating over the free vars
using with_freevars.
(and of course they are not quite statics either).
Namely, they *do* have a restricted region (like rvalues), but they
also cannot be moved out of (like statics).
`PointerKind` is included in `LoanPath` and hence forms part of the
equality check; this led to having two unequal paths that both
represent `*x`, depending on whether the `*` was inserted
automatically or explicitly. Bad mojo. The `note` field, in contrast,
is intended more-or-less primarily for this purpose of adding extra
data.
`cmt` is a ref-counted wrapper around `cmt_` The use of refcounting
keeps `cmt` handling simple, but a lot of `cmt` instances are very
short-lived, and heap-allocating the short-lived ones takes up time.
This patch changes things in the following ways.
- Most of the functions that produced `cmt` instances now produce `cmt_`
instances. The `Rc::new` calls that occurred within those functions
now occur at their call sites (but only when necessary, which isn't
that often).
- Many of the functions that took `cmt` arguments now take `&cmt_`
arguments. This includes all the methods in the `Delegate` trait.
As a result, the vast majority of the heap allocations are avoided. In
an extreme case, the number of calls to malloc in tuple-stress drops
from 9.9M to 7.9M, a drop of 20%. And the compile times for many runs of
coercions, deep-vector, and tuple-stress drop by 1--2%.
We used to make the upvar types in the closure `==` but that was
stronger than we needed. Subtyping suffices, since we are copying the
upvar value into the closure field. This in turn allows us to infer
smaller lifetimes in captured values in some cases (like the example
here), avoiding errors.
incr.comp.: Implement query result cache and use it to cache type checking tables.
This is a spike implementation of caching more than LLVM IR and object files when doing incremental compilation. At the moment, only the `typeck_tables_of` query is cached but MIR and borrow-check will follow shortly. The feature is activated by running with `-Zincremental-queries` in addition to `-Zincremental`, it is not yet active by default.
r? @nikomatsakis
Eduard-Mihai Burtescu
ljedrz
bors
Mazdak Farrokhzad
Taiki Endo
Blitzerr
Mark Rousskov
John Kåre Alsaker
Felix S. Klock II
varkor
csmoe
Esteban Küber
Niko Matsakis
Nicholas Nethercote
Michael Woerister
Douglas Campos
Alex Crichton