bors [Sun, 7 Oct 2018 03:07:16 +0000 (03:07 +0000)]
Auto merge of #54451 - alexcrichton:no-mangle-extern-linkage, r=michaelwoerister
rustc: Allow `#[no_mangle]` anywhere in a crate
This commit updates the compiler to allow the `#[no_mangle]` (and
`#[export_name]` attributes) to be located anywhere within a crate.
These attributes are unconditionally processed, causing the compiler to
always generate an exported symbol with the appropriate name.
After some discussion on #54135 it was found that not a great reason
this hasn't been allowed already, and it seems to match the behavior
that many expect! Previously the compiler would only export a
`#[no_mangle]` symbol if it were *publicly reachable*, meaning that it
itself is `pub` and it's otherwise publicly reachable from the root of
the crate. This new definition is that `#[no_mangle]` *is always
reachable*, no matter where it is in a crate or whether it has `pub` or
not.
This should make it much easier to declare an exported symbol with a
known and unique name, even when it's an internal implementation detail
of the crate itself. Note that these symbols will persist beyond LTO as
well, always making their way to the linker.
Along the way this commit removes the `private_no_mangle_functions` lint
(also for statics) as there's no longer any need to lint these
situations. Furthermore a good number of tests were updated now that
symbol visibility has been changed.
bors [Sun, 7 Oct 2018 00:28:26 +0000 (00:28 +0000)]
Auto merge of #54782 - pnkfelix:issue-54556-semi-on-tail-diagnostic, r=nikomatsakis
NLL: temps in block tail expression diagnostic
This change adds a diagnostic that explains when temporaries in a block tail expression live longer than block local variables that they borrow, and attempts to suggest turning the tail expresion into a statement (either by adding a semicolon at the end, when its result value is clearly unused, or by introducing a `let`-binding for the result value and then returning that).
Alex Crichton [Fri, 21 Sep 2018 22:58:11 +0000 (15:58 -0700)]
rustc: Allow `#[no_mangle]` anywhere in a crate
This commit updates the compiler to allow the `#[no_mangle]` (and
`#[export_name]` attributes) to be located anywhere within a crate.
These attributes are unconditionally processed, causing the compiler to
always generate an exported symbol with the appropriate name.
After some discussion on #54135 it was found that not a great reason
this hasn't been allowed already, and it seems to match the behavior
that many expect! Previously the compiler would only export a
`#[no_mangle]` symbol if it were *publicly reachable*, meaning that it
itself is `pub` and it's otherwise publicly reachable from the root of
the crate. This new definition is that `#[no_mangle]` *is always
reachable*, no matter where it is in a crate or whether it has `pub` or
not.
This should make it much easier to declare an exported symbol with a
known and unique name, even when it's an internal implementation detail
of the crate itself. Note that these symbols will persist beyond LTO as
well, always making their way to the linker.
Along the way this commit removes the `private_no_mangle_functions` lint
(also for statics) as there's no longer any need to lint these
situations. Furthermore a good number of tests were updated now that
symbol visibility has been changed.
bors [Sat, 6 Oct 2018 10:44:11 +0000 (10:44 +0000)]
Auto merge of #54766 - alexcrichton:wasm-all-symbols, r=michaelwoerister
wasm: Explicitly export all symbols with LLD
This commit fixes an oddity on the wasm target where LTO can produce
working executables but plain old optimizations doesn't. The compiler
already knows what set of symbols it would like to export, but LLD only
discovers this list transitively through symbol visibilities. LLD may
not, however, always find all the symbols that we'd like to export.
For example if you depend on an rlib with a `#[no_mangle]` symbol, then
if you don't actually use anything from the rlib then the symbol won't
appear in the final artifact! It will appear, however, with LTO. This
commit attempts to rectify this situation by ensuring that all symbols
rustc would otherwise preserve through LTO are also preserved through
the linking process with LLD by default.
bors [Sat, 6 Oct 2018 00:44:11 +0000 (00:44 +0000)]
Auto merge of #54859 - pietroalbini:rollup, r=pietroalbini
Rollup of 11 pull requests
Successful merges:
- #54078 (Expand the documentation for the `std::sync` module)
- #54717 (Cleanup rustc/ty part 1)
- #54781 (Add examples to `TyKind::FnDef` and `TyKind::FnPtr` docs)
- #54787 (Only warn about unused `mut` in user-written code)
- #54804 (add suggestion for inverted function parameters)
- #54812 (Regression test for #32382.)
- #54833 (make `Parser::parse_foreign_item()` return a foreign item or error)
- #54834 (rustdoc: overflow:auto doesn't work nicely on small screens)
- #54838 (Fix typo in src/libsyntax/parse/parser.rs)
- #54851 (Fix a regression in 1.30 by reverting #53564)
- #54853 (Remove unneccessary error from test, revealing NLL error.)
Pietro Albini [Fri, 5 Oct 2018 20:33:21 +0000 (22:33 +0200)]
Rollup merge of #54851 - alexcrichton:revert-optimize, r=sfackler
Fix a regression in 1.30 by reverting #53564
Investigation on #54477 revealed https://github.com/rust-lang/rust/pull/53564 as the culprit in the regression for that crate. I've reproduced the regression with the [detailed test cases provided](https://github.com/rust-lang/rust/issues/54477#issuecomment-427398456). While we figure out how to fix the regression this commit reverts the current culprit.
Pietro Albini [Fri, 5 Oct 2018 20:33:17 +0000 (22:33 +0200)]
Rollup merge of #54833 - abonander:issue-54441, r=petrochenkov
make `Parser::parse_foreign_item()` return a foreign item or error
Fixes `Parser::parse_foreign_item()` to follow the convention of `parse_trait_item()` and `parse_impl_item()` in that it *must* parse an item or return an error, and then the caller is responsible for detecting the closing delimiter.
This prevents it from looping endlessly on an unexpected token in `ext/expand.rs` where it was also leaking memory by continually pushing to `Parser::expected_tokens` via `Parser::check_keyword()`.
Pietro Albini [Fri, 5 Oct 2018 20:33:11 +0000 (22:33 +0200)]
Rollup merge of #54717 - ljedrz:cleanup_ty_p1, r=davidtwco
Cleanup rustc/ty part 1
Part 2 will follow soon; I wouldn't want these changes to rot too quickly.
- improve stack shifting and remove related allocations
- move a faster early return up
- improve allocations
- use Cow<str> where applicable
- simplify common patterns
- whitespace fixes
Pietro Albini [Fri, 5 Oct 2018 20:33:10 +0000 (22:33 +0200)]
Rollup merge of #54078 - GabrielMajeri:expand-sync-docs, r=steveklabnik
Expand the documentation for the `std::sync` module
I've tried to expand the documentation for Rust's synchronization primitives. The module level documentation explains why synchronization is required when working with a multiprocessor system,
and then links to the appropiate structure in this module.
Fixes #29377, since this should be the last item on the checklist (documentation for `Atomic*` was fixed in #44854, but not ticked off the checklist).
bors [Fri, 5 Oct 2018 19:32:14 +0000 (19:32 +0000)]
Auto merge of #54743 - ljedrz:cleanup_ty_p2, r=zackmdavis
Cleanup rustc/ty part 2
The second part of cleanups and minor improvements for rustc/ty.
- improve allocations
- calculate span after a possible early continue
- simplify some patterns
- mark a comment as FIXME
- whitespace fixes
bors [Fri, 5 Oct 2018 12:52:53 +0000 (12:52 +0000)]
Auto merge of #54336 - petrochenkov:preuni, r=alexcrichton
resolve: Some refactorings in preparation for uniform paths 2.0
The main result is that in-scope resolution performed during macro expansion / import resolution is now consolidated in a single function (`fn early_resolve_ident_in_lexical_scope`), which can now be used for resolving first import segments as well when uniform paths are enabled.
bors [Fri, 5 Oct 2018 10:08:01 +0000 (10:08 +0000)]
Auto merge of #52121 - jebrosen:macros2_feature, r=petrochenkov
Merge `proc_macro_` expansion feature gates as `proc_macro_hygiene`
Merges `proc_macro_mod`, `proc_macro_expr`, `proc_macro_non_items`, and `proc_macro_gen` into a single feature: `proc_macro_hygiene`. These features are not all blocked on implementing macro hygiene *per se*, but rather on interactions with hygiene that have not been entirely resolved.
Improve diagnostics for borrow-check errors that result from drops of temporary r-values.
Changed `BorrowExplanation::UsedLaterWhenDropped` to handle both named
locals and also unnamed (aka temporaries).
If the dropped temporary does not implement `Drop`, then we print its
full type; but when the dropped temporary is itself an ADT `D` that
implements `Drop`, then diagnostic points the user directly at `D`.
Have `add_explanation_to_diagnostic` also take `Mir` as parameter.
This is preparation for allowing the `BorrowExplanation` carry things
like `mir::Location` or `mir::Local` and still be able to generate
usable diagnostic text.
Alpha-rename `BorrowExplanation::emit` to `BorrowExplanation::add_explanation_to_diagnostic`.
(I found it confusing to have calls to an `emit` method in our
error_reporting module where that `emit` method *wasn't* the
`DiagnosticBuffer::emit` method.)
expansion: Remove restriction on use of macro attributes with test/bench
The restrictions were introduced in https://github.com/rust-lang/rust/pull/54277 and no longer necessary now because legacy plugins are now expanded in usual left-to-right order
bors [Fri, 5 Oct 2018 01:57:01 +0000 (01:57 +0000)]
Auto merge of #54017 - alexcrichton:wasm-atomics2, r=sfackler
std: Start implementing wasm32 atomics
This commit is an initial start at implementing the standard library for
wasm32-unknown-unknown with the experimental `atomics` feature enabled. None of
these changes will be visible to users of the wasm32-unknown-unknown target
because they all require recompiling the standard library. The hope with this is
that we can get this support into the standard library and start iterating on it
in-tree to enable experimentation.
Currently there's a few components in this PR:
* Atomic fences are disabled on wasm as there's no corresponding atomic op and
it's not clear yet what the convention should be, but this will change in the
future!
* Implementations of `Mutex`, `Condvar`, and `RwLock` were all added based on
the atomic intrinsics that wasm has.
* The `ReentrantMutex` and thread-local-storage implementations panic currently
as there's no great way to get a handle on the current thread's "id" yet.
Right now the wasm32 target with atomics is unfortunately pretty unusable,
requiring a lot of manual things here and there to actually get it operational.
This will likely continue to evolve as the story for atomics and wasm unfolds,
but we also need more LLVM support for some operations like custom `global`
directives for this to work best.
bors [Thu, 4 Oct 2018 20:28:57 +0000 (20:28 +0000)]
Auto merge of #54649 - nikomatsakis:universes-refactor-1, r=scalexm
adopt "placeholders" to represent universally quantified regions
This does a few preliminary refactorings that lay some groundwork for moving towards universe integration. Two things, primarily:
- Rename from "skolemized" to "placeholder"
- When instantiating `for<'a, 'b, 'c>`, just create one universe for all 3 regions, and distinguish them from one another using the `BoundRegion`.
- This is more accurate, and I think that in general we'll be moving towards a model of separating "binder" (universe, debruijn index) from "index within binder" in a number of places.
- In principle, it feels the current setup of making lots of universes could lead to us doing the wrong thing, but I've actually not been able to come up with an example where this is so.
bors [Thu, 4 Oct 2018 16:34:27 +0000 (16:34 +0000)]
Auto merge of #54666 - matthewjasper:mir-function-spans, r=pnkfelix
[NLL] Improve "borrow later used here" messages
* In the case of two conflicting borrows, the later used message says which borrow it's referring to
* If the later use is a function call (from the users point of view) say that the later use is for the call. Point just to the function.
bors [Thu, 4 Oct 2018 11:39:50 +0000 (11:39 +0000)]
Auto merge of #54809 - pietroalbini:rollup, r=pietroalbini
Rollup of 10 pull requests
Successful merges:
- #53523 (Add doc for impl From for Std Error)
- #54746 (simplify some unused lints code)
- #54761 (Make spec_extend use for_each())
- #54769 (Fix typo in CONTRIBUTING.md)
- #54773 (Update a FIXME in memory.rs)
- #54777 (abolish ICE when pretty-printing async block)
- #54780 (Remove duplicate predicates in `explicit_predicates_of`)
- #54788 (A handful of cleanups for rustc/mir)
- #54789 (Introduce `TyKind::UnnormalizedProjection`)
- #54795 (remove padding from multiline format string label)
Pietro Albini [Thu, 4 Oct 2018 10:20:15 +0000 (12:20 +0200)]
Rollup merge of #54788 - ljedrz:cleanup_rustc_mir, r=oli-obk
A handful of cleanups for rustc/mir
- use the "regular" `into()` instead of `graphviz::IntoCow` in `mod.rs`
- `format!("{}", x)` > `x.to_string()`
- remove one unnecessary `String` allocation
- shorten the logic of one loop
- `assert!(x == y)` > `assert_eq!(x, y)`
- whitespace & formatting fixes
Pietro Albini [Thu, 4 Oct 2018 10:20:13 +0000 (12:20 +0200)]
Rollup merge of #54780 - scalexm:dup-predicates, r=nikomatsakis
Remove duplicate predicates in `explicit_predicates_of`
I took a more brutal approach than described in #52187. I could have used the `linked_hash_map` crate but this seems overkill, especially as we need a vec storage in the end.
Pietro Albini [Thu, 4 Oct 2018 10:20:12 +0000 (12:20 +0200)]
Rollup merge of #54777 - zackmdavis:async_pretty_ice, r=cramertj
abolish ICE when pretty-printing async block
@jnetterf reported an ICE when the unused-parentheses lint triggered around an async block (#54752). In order to compose an autofixable suggestion, the lint invokes the pretty-printer on the unnecessarily-parenthesized expression. (One wonders why the lint doesn't just use `SourceMap::span_to_snippet` instead, to preserve the formatting of the original source?—but to answer that, you'd have to ask the author of 5c9f806d.)
But then the pretty-printer panics when trying to call `<pprust::State as PrintState>::end` when `State.boxes` is empty. Empirically, the problem would seem to be solved if we start some "boxes" beforehand in the `ast::ExprKind::Async` arm of the big match in `print_expr_outer_attr_style`, exactly like we do in the immediately-preceding match arm for `ast::ExprKind::Block`—it would seem pretty ("pretty") reasonable for the pretty-printing of async blocks to work a lot like the pretty-printing of ordinary non-async blocks, right??
Of course, it would be shamefully cargo-culty to commit code on the basis of this kind of mere reasoning-by-analogy (in contrast to understanding the design of the pretty-printer in such detail that the correctness of the patch is comprehended with all the lucid certainty of mathematical proof, rather than being merely surmised by intuition). But maybe we care more about fixing the bug with high probability today, than with certainty in some indefinite hypothetical future? Maybe the effort is worth [a fifth of a shirt](https://hacktoberfest.digitalocean.com/stats/zackmdavis)??
Pietro Albini [Thu, 4 Oct 2018 10:20:11 +0000 (12:20 +0200)]
Rollup merge of #54773 - rust-lang:wesleywiser-patch-1, r=oli-obk
Update a FIXME in memory.rs
In #51833, I improved the performance of `copy_undef_mask()`. As such, the old FIXME wasn't appropriate anymore. The main remaining thing left to do is to implement a fast path for non-overlapping copies (per @oli-obk).
Pietro Albini [Thu, 4 Oct 2018 10:20:08 +0000 (12:20 +0200)]
Rollup merge of #54761 - Lucretiel:patch-1, r=cramertj
Make spec_extend use for_each()
`for_each` will use an iterator's own implementation of `try_fold`, which I understand to be generally preferable (because nested iterator adapter's will use each other's `try_fold` and be designed for the specific adaptation in a way that promotes performance and inlining.