By putting an "unreachable" instruction into the default arm of a switch
instruction we can let LLVM know that the match is exhaustive, allowing
for better optimizations.
For example, this match:
```rust
pub enum Enum {
One,
Two,
Three,
}
impl Enum {
pub fn get_disc(self) -> u8 {
match self {
Enum::One => 0,
Enum::Two => 1,
Enum::Three => 2,
}
}
}
```
Currently compiles to this on x86_64:
```asm
.cfi_startproc
movzbl %dil, %ecx
cmpl $1, %ecx
setne %al
testb %cl, %cl
je .LBB0_2
incb %al
movb %al, %dil
.LBB0_2:
movb %dil, %al
retq
.Lfunc_end0:
```
But with this change we get:
```asm
.cfi_startproc
movb %dil, %al
retq
.Lfunc_end0:
```
As discussed in the referenced issues, this PR makes rustc emit `__imp_<symbol>` stubs for all public static data to ensure smooth linking in on `-windows-msvc` targets.
Resolves#26591, cc #27438
This commit updates the `MatchIndices` and `RMatchIndices` iterators to follow
the same pattern as the `chars` and `char_indices` iterators. The `matches`
iterator currently yield `&str` elements, so the `MatchIndices` iterator now
yields the index of the match as well as the `&str` that matched (instead of
start/end indexes).
cc #27743
Because of type inference, duplicate obligations exist and cause duplicate
errors. To avoid this, only display the first error for each (predicate,span).
The inclusion of the span is somewhat bikesheddy, but *is* the more
conservative option (it does not remove some instability, as duplicate
obligations are ignored by `duplicate_set` under some inference conditions).
Fixes#28098
cc #21528 (is it a dupe?)
This PR removes random remaining `Ident`s outside of libsyntax and performs general cleanup
In particular, interfaces of `Name` and `Ident` are tidied up, `Name`s and `Ident`s being small `Copy` aggregates are always passed to functions by value, and `Ident`s are never used as keys in maps, because `Ident` comparisons are tricky.
Although this PR closes https://github.com/rust-lang/rust/issues/6993 there's still work related to it:
- `Name` can be made `NonZero` to compress numerous `Option<Name>`s and `Option<Ident>`s but it requires const unsafe functions.
- Implementation of `PartialEq` on `Ident` should be eliminated and replaced with explicit hygienic, non-hygienic or member-wise comparisons.
- Finally, large parts of AST can potentially be converted to `Name`s in the same way as HIR to clearly separate identifiers used in hygienic and non-hygienic contexts.
r? @nrc
This adds a new target property, `target_vendor`. It is to be be used as a matcher for conditional compilation. The vendor is part of the [autoconf target triple](http://llvm.org/docs/doxygen/html/classllvm_1_1Triple.html#details): `<arch><sub>-<vendor>-<os>-<env>`. `arch`, `target_os` and `target_env` are already supported by Rust.
This change was suggested in PR #28593. It enables conditional compilation based on the vendor. This is needed for the rumprun target, which needs to match against both, target_os and target_vendor.
The default value for `target_vendor` is "unknown", "apple" and "pc" are other common values.
Matching against the `target_vendor` is introduced behind the feature gate `#![feature(cfg_target_vendor)]`.
This is the first time I messed around with rustc internals. I just added the my code where I found the existing `target_*` variables, hopefully I haven't missed anything. Please review with care. :)
r? @alexcrichton
This commit updates the `MatchIndices` and `RMatchIndices` iterators to follow
the same pattern as the `chars` and `char_indices` iterators. The `matches`
iterator currently yield `&str` elements, so the `MatchIndices` iterator now
yields the index of the match as well as the `&str` that matched (instead of
start/end indexes).
cc #27743
By putting an "unreachable" instruction into the default arm of a switch
instruction we can let LLVM know that the match is exhaustive, allowing
for better optimizations.
For example, this match:
```rust
pub enum Enum {
One,
Two,
Three,
}
impl Enum {
pub fn get_disc(self) -> u8 {
match self {
Enum::One => 0,
Enum::Two => 1,
Enum::Three => 2,
}
}
}
```
Currently compiles to this on x86_64:
```asm
.cfi_startproc
movzbl %dil, %ecx
cmpl $1, %ecx
setne %al
testb %cl, %cl
je .LBB0_2
incb %al
movb %al, %dil
.LBB0_2:
movb %dil, %al
retq
.Lfunc_end0:
```
But with this change we get:
```asm
.cfi_startproc
movb %dil, %al
retq
.Lfunc_end0:
```
Make sure Name, SyntaxContext and Ident are passed by value
Make sure Idents don't serve as keys (or parts of keys) in maps, Ident comparison is not well defined
This adds a new target property, `target_vendor` which can be used as a
matcher for conditional compilation. The vendor is part of the autoconf
target triple: <arch><sub>-<vendor>-<os>-<env>
The default value for `target_vendor` is "unknown".
Matching against the `target_vendor` with `#[cfg]` is currently feature
gated as `cfg_target_vendor`.
extend the search path of libraries to /usr/local/lib in `run-make`
testsuite. It should permit to find libstdc++.so on usual directory.
r? @alexcrichton
Part of https://github.com/rust-lang/rust/issues/6993
This patch replaces `Ident`s with `Name`s in data structures of HIR and updates the dependent crates to compile and pass `make check`.
Some HIR structures still use `Ident`s, namely `PathSegment`, `PatIdent`, `ExprWhile`, `ExprLoop`, `ExprBreak` and `ExprAgain`, they need them for resolve (but `PathSegment` is special, see https://github.com/rust-lang/rust/issues/6993#issuecomment-141256292).
r? @nrc
Fixes#16264 / #18241.
As far as I can tell, it should be impossible for a trait to be inaccessible if it's in scope, so this check is unnecessary. Are there any cases where this check is actually needed?
Fixes#28279.
Currently
`common_supertype(*mut for<'a> Fn(&'a usize), *mut for<'a> Fn(&'a usize) + 'static)`
equals `*mut Fn(&usize)` which seems to be caused by `higher_ranked_sub()` allowing region variables to escape the comparison. This prevents inference from working properly with stuff like `Rc<Fn(&T)>`.
r? @nikomatsakis
Since 1.3.0 the BufWriter has seen tremendous speedups. So when I use it in the shootout benchmarks, I see some nice speedup (which up to 1.2.0 was nixed by the pessimizations during initialization).
I assume the expected error changed during the development of pull
request #28321 and that wasn't noticed because the test was
accidentally not running.
r? @nikomatsakis
I assume the expected error changed during the development of pull
request #28321 and that wasn't noticed because the test was
accidentally not running.
