Use two vectors in nearest_common_ancestor.
When looking at any scope in scope chain A, we only need to look for
matches among scopes previously seen in scope chain B, and vice versa.
This halves the number of "seen before?" comparisons, speeding up some
runs of style-servo, clap-rs, and syn by 1--2%.
Thanks to @kirillkh for the suggestion.
r? @nikomatsakis
`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%.
guard expressions of matches (activated only when using
new NLL mode).
Review feedback: removed 27282 from filename. (The test still
references it in a relevant comment in the file itself so that seemed
like a reasonable compromise.)
deref'ing such borrows within that guard.
Review feedback: Add comment noting a point where we may or may not
need to add a cast when we finish the work on rust-lang/rust#27282.
Review feedback: Pass a newtype'd `ArmHasGuard` rather than a raw boolean.
Review feedback: toggle "ref binding in guards" semantics via specific
method. (This should ease a follow-up PR that just unconditionally
adopts the new semantics.)
Implement tool_attributes feature (RFC 2103)
cc #44690
This is currently just a rebased and compiling (hopefully) version of #47773.
Let's see if travis likes this. I will add the implementation for `tool_lints` this week.
Reduce maximum repr(align(N)) to 2^29
The current maximum `repr(align(N))` alignment is larger than the maximum alignment accepted by LLVM, which can cause issues for huge values of `N`, as seen in #49492. Fixes#49492.
r? @rkruppe
Fix a warning in libcore on 16bit targets.
This code is assuming that usize >= 32bits, but it is not the case on
16bit targets. It is producing a warning that can fail the compilation
on MSP430 if deny(warnings) is enabled.
It is very unlikely that someone would actually use this code on
a microcontroller, but since unicode was merged into libcore we
have to compile it on 16bit targets.
I've tried to make sure that the code stays the same on x86,
here is an assembly comparison: https://godbolt.org/g/wFw7dZ
r? @SimonSapin
This avoids converting every char to \u{...} form, which bloats the
resulting strings unnecessarily. It also provides consistency with the
existing escape_default() calls in LitKind::token() used for raw
string literals, char literals, and raw byte char literals.
There are two benefits from this change.
- Compilation is faster. Most of the rustc-perf benchmarks see a
non-trivial speedup, particularly for incremental rebuilds, with the
best speedup over 13%, and multiple others over 10%.
- Generated rlibs are smaller. An extreme example is libfutures.rlib,
which shrinks from 2073306 bytes to 1765927 bytes, a 15% reduction.
Fix an unresolved import issue with enabled `use_extern_macros`
This is a kinda ugly special-purpose solution that will break if we suddenly add a fourth namespace, but I hope to come up with something more general if I get to import resolution refactoring this summer.
Fixes https://github.com/rust-lang/rust/issues/50187 thus removing a blocker for stabilization of `use_extern_macros`
