Commit Graph

467 Commits

Author SHA1 Message Date
bors
d5f9c40e6a Auto merge of #93466 - cjgillot:query-dead, r=nagisa
Make dead code check a query.

Dead code check is run for each invocation of the compiler, even if no modifications were involved.
This PR makes dead code check a query keyed on the module. This allows to skip the check when a module has not changed.
To perform this, a query `live_symbols_and_ignored_derived_traits` is introduced to encapsulate the global analysis of finding live symbols. The second query `check_mod_deathness` outputs diagnostics for each module based on this first query's results.
2022-02-02 02:29:32 +00:00
Camille GILLOT
4e7d47bb6c Make dead code check a query. 2022-02-01 13:11:03 +01:00
lcnr
4bbe970673 review + rebase 2022-02-01 10:29:36 +01:00
lcnr
a1a30f7548 add a rustc::query_stability lint 2022-02-01 10:15:59 +01:00
Maybe Waffle
4ca56d2888 Check that #[rustc_must_implement_one_of] is applied to a trait 2022-01-27 22:07:16 +03:00
Tomasz Miąsko
beeba4bcea Reject may_unwind option in naked functions 2022-01-21 00:00:00 +00:00
Tomasz Miąsko
888332fee4 Reject unsupported naked functions
Transition unsupported naked functions future incompatibility lint into
an error:

* Naked functions must contain a single inline assembly block.
  Introduced as future incompatibility lint in 1.50 #79653.
  Change into an error fixes a soundness issue described in #32489.

* Naked functions must not use any forms of inline attribute.
  Introduced as future incompatibility lint in 1.56 #87652.
2022-01-21 17:38:21 +01:00
Matthias Krüger
3d10c64b26
Rollup merge of #91032 - eholk:generator-drop-tracking, r=nikomatsakis
Introduce drop range tracking to generator interior analysis

This PR addresses cases such as this one from #57478:
```rust
struct Foo;
impl !Send for Foo {}

let _: impl Send = || {
    let guard = Foo;
    drop(guard);
    yield;
};
```

Previously, the `generator_interior` pass would unnecessarily include the type `Foo` in the generator because it was not aware of the behavior of `drop`. We fix this issue by introducing a drop range analysis that finds portions of the code where a value is guaranteed to be dropped. If a value is dropped at all suspend points, then it is no longer included in the generator type. Note that we are using "dropped" in a generic sense to include any case in which a value has been moved. That is, we do not only look at calls to the `drop` function.

There are several phases to the drop tracking algorithm, and we'll go into more detail below.
1. Use `ExprUseVisitor` to find values that are consumed and borrowed.
2. `DropRangeVisitor` uses consume and borrow information to gather drop and reinitialization events, as well as build a control flow graph.
3. We then propagate drop and reinitialization information through the CFG until we reach a fix point (see `DropRanges::propagate_to_fixpoint`).
4. When recording a type (see `InteriorVisitor::record`), we check the computed drop ranges to see if that value is definitely dropped at the suspend point. If so, we skip including it in the type.

## 1. Use `ExprUseVisitor` to find values that are consumed and borrowed.

We use `ExprUseVisitor` to identify the places where values are consumed. We track both the `hir_id` of the value, and the `hir_id` of the expression that consumes it. For example, in the expression `[Foo]`, the `Foo` is consumed by the array expression, so after the array expression we can consider the `Foo` temporary to be dropped.

In this process, we also collect values that are borrowed. The reason is that the MIR transform for generators conservatively assumes anything borrowed is live across a suspend point (see `rustc_mir_transform::generator::locals_live_across_suspend_points`). We match this behavior here as well.

## 2. Gather drop events, reinitialization events, and control flow graph

After finding the values of interest, we perform a post-order traversal over the HIR tree to find the points where these values are dropped or reinitialized. We use the post-order index of each event because this is how the existing generator interior analysis refers to the position of suspend points and the scopes of variables.

During this traversal, we also record branching and merging information to handle control flow constructs such as `if`, `match`, and `loop`. This is necessary because values may be dropped along some control flow paths but not others.

## 3. Iterate to fixed point

The previous pass found the interesting events and locations, but now we need to find the actual ranges where things are dropped. Upon entry, we have a list of nodes ordered by their position in the post-order traversal. Each node has a set of successors. For each node we additionally keep a bitfield with one bit per potentially consumed value. The bit is set if we the value is dropped along all paths entering this node.

To compute the drop information, we first reverse the successor edges to find each node's predecessors. Then we iterate through each node, and for each node we set its dropped value bitfield to the intersection of all incoming dropped value bitfields.

If any bitfield for any node changes, we re-run the propagation loop again.

## 4. Ignore dropped values across suspend points

At this point we have a data structure where we can ask whether a value is guaranteed to be dropped at any post order index for the HIR tree. We use this information in `InteriorVisitor` to check whether a value in question is dropped at a particular suspend point. If it is, we do not include that value's type in the generator type.

Note that we had to augment the region scope tree to include all yields in scope, rather than just the last one as we did before.

r? `@nikomatsakis`
2022-01-20 23:37:29 +01:00
Matthias Krüger
9a82f74cdf
Rollup merge of #92783 - FabianWolff:issue-92726, r=nikomatsakis
Annotate dead code lint with notes about ignored derived impls

Fixes #92726. CC `@pmetzger,` is this what you had in mind?

r? `@nikomatsakis`
2022-01-19 10:42:16 +01:00
Eric Holk
904c270149 More comments and small cleanups 2022-01-18 14:25:26 -08:00
Eric Holk
c4dee40170 Track drops across multiple yields 2022-01-18 14:25:24 -08:00
Eric Holk
f712df8c5d Track drop points in generator_interior
This change adds the basic infrastructure for tracking drop ranges in
generator interior analysis, which allows us to exclude dropped types
from the generator type.

Not yet complete, but many of the async/await and generator tests pass.
The main missing piece is tracking branching control flow (e.g. around
an `if` expression). The patch does include support, however, for
multiple yields in th e same block.

Issue #57478
2022-01-18 14:25:23 -08:00
bors
9ad5d82f82 Auto merge of #92731 - bjorn3:asm_support_changes, r=nagisa
Avoid unnecessary monomorphization of inline asm related functions

This should reduce build time for codegen backends by avoiding duplicated monomorphization of certain inline asm related functions for each passed in closure type.
2022-01-18 14:32:52 +00:00
bors
7bc7be860f Auto merge of #87648 - JulianKnodt:const_eq_constrain, r=oli-obk
allow eq constraints on associated constants

Updates #70256

(cc `@varkor,` `@Centril)`
2022-01-18 09:58:39 +00:00
Matthias Krüger
804072fdfc
Rollup merge of #92701 - ehuss:even-more-attr-validation, r=matthewjasper
Add some more attribute validation

This adds some more validation for the position of attributes:

* `link` is only valid on an `extern` block
* `windows_subsystem` and `no_builtins` are only valid at the crate level
2022-01-18 04:41:59 +01:00
kadmin
0765999622 add eq constraints on associated constants 2022-01-17 17:20:57 +00:00
bjorn3
9336fe33d7 Fix review comment 2022-01-17 18:06:30 +01:00
bjorn3
991cbd1503 Use Symbol for target features in asm handling
This saves a couple of Symbol::intern calls
2022-01-17 18:06:27 +01:00
bors
ee5d8d37ba Auto merge of #90986 - camsteffen:nested-filter, r=cjgillot
Replace `NestedVisitorMap` with generic `NestedFilter`

This is an attempt to make the `intravisit::Visitor` API simpler and "more const" with regard to nested visiting.

With this change, `intravisit::Visitor` does not visit nested things by default, unless you specify `type NestedFilter = nested_filter::OnlyBodies` (or `All`). `nested_visit_map` returns `Self::Map` instead of `NestedVisitorMap<Self::Map>`. It panics by default (unreachable if `type NestedFilter` is omitted).

One somewhat trixty thing here is that `nested_filter::{OnlyBodies, All}` live in `rustc_middle` so that they may have `type Map = map::Map` and so that `impl Visitor`s never need to specify `type Map` - it has a default of `Self::NestedFilter::Map`.
2022-01-17 14:50:50 +00:00
bors
a34c079752 Auto merge of #92816 - tmiasko:rm-llvm-asm, r=Amanieu
Remove deprecated LLVM-style inline assembly

The `llvm_asm!` was deprecated back in #87590 1.56.0, with intention to remove
it once `asm!` was stabilized, which already happened in #91728 1.59.0. Now it
is time to remove `llvm_asm!` to avoid continued maintenance cost.

Closes #70173.
Closes #92794.
Closes #87612.
Closes #82065.

cc `@rust-lang/wg-inline-asm`

r? `@Amanieu`
2022-01-17 09:40:29 +00:00
bors
fd20513f52 Auto merge of #92473 - petrochenkov:ltrattr2, r=Aaron1011
expand: Pick `cfg`s and `cfg_attrs` one by one, like other attributes

This is a rebase of https://github.com/rust-lang/rust/pull/83354, but without any language-changing parts ~(except for https://github.com/rust-lang/rust/pull/84110)~, i.e. the attribute expansion order is the same.

This is a pre-requisite for any other changes making cfg attributes closer to regular macro attributes
- Possibly changing their expansion order (https://github.com/rust-lang/rust/issues/83331)
- Keeping macro backtraces for cfg attributes, or otherwise making them visible after expansion without keeping them in place literally (https://github.com/rust-lang/rust/pull/84110).

Two exceptions to the "one by one" behavior are:
- cfgs eagerly expanded by `derive` and `cfg_eval`, they are still expanded in a batch, that's by design.
- cfgs at the crate root, they are currently expanded not during the main expansion pass, but before that, during `#![feature]` collection. I'll try to disentangle that logic later in a separate PR.

r? `@Aaron1011`
2022-01-17 02:06:54 +00:00
Cameron Steffen
45db716902 Replace NestedVisitorMap with NestedFilter 2022-01-16 16:02:36 -06:00
Matthias Krüger
c5041f88ea
Rollup merge of #92646 - mdibaiee:76935/pass-by-value, r=lcnr
feat: rustc_pass_by_value lint attribute

Useful for thin wrapper attributes that are best passed as value instead
of reference.

Fixes #76935
2022-01-16 16:58:15 +01:00
Camille GILLOT
67727aa7c3 Reduce use of local_def_id_to_hir_id. 2022-01-15 21:26:25 +01:00
Camille GILLOT
79afe99973 Use LocalDefId in rustc_passes::hir_id_validator. 2022-01-15 21:26:24 +01:00
Camille GILLOT
c9de7d7a20 Use LocalDefId in rustc_passes::entry. 2022-01-15 21:26:24 +01:00
Camille GILLOT
60064726ae Return a LocalDefId in get_parent_item. 2022-01-15 21:26:20 +01:00
Fabian Wolff
8b459dd738 Use span of ignored impls for explanatory note 2022-01-15 21:02:50 +01:00
bors
22e491ac7e Auto merge of #89861 - nbdd0121:closure, r=wesleywiser
Closure capture cleanup & refactor

Follow up of #89648

Each commit is self-contained and the rationale/changes are documented in the commit message, so it's advisable to review commit by commit.

The code is significantly cleaner (at least IMO), but that could have some perf implication, so I'd suggest a perf run.

r? `@wesleywiser`
cc `@arora-aman`
2022-01-13 18:51:07 +00:00
Tomasz Miąsko
000b36c505 Remove deprecated LLVM-style inline assembly 2022-01-12 18:51:31 +01:00
Fabian Wolff
bd1f09d417 Annotate dead code lint with notes about ignored derived impls 2022-01-11 21:06:18 +01:00
Mahdi Dibaiee
91ed6892f7
rustc_pass_by_value lint: add test on custom types 2022-01-10 17:42:20 +00:00
Vadim Petrochenkov
e87ce7ad74 expand: Pick cfgs and cfg_attrs one by one, like other attributes 2022-01-10 18:11:44 +08:00
Eric Huss
2b7572092c Clean up lang_items::extract
Noted in https://github.com/rust-lang/rust/pull/87739#pullrequestreview-740497194,
lang_items::extract no longer needs to take a closure.
2022-01-09 13:41:04 -08:00
Eric Huss
59d4bae018 Add validation for link attribute position. 2022-01-09 11:28:40 -08:00
Mahdi Dibaiee
4c3e330a8c
feat: pass_by_value lint attribute
Useful for thin wrapper attributes that are best passed as value instead
of reference.
2022-01-09 13:05:51 +00:00
Gary Guo
3698e03fb6 Remove span from UpvarCapture::ByValue
This span is unused and is superseded by capture_kind_expr_id in CaptureInfo
2022-01-07 22:54:28 +00:00
Matthew Jasper
3b7d496f72 Add query to avoid name comparison in leaf_def 2022-01-07 13:31:36 -08:00
Matthew Jasper
d7595853a2 Add trait_item_def_id to AssocItem
This allows avoiding some lookups by name
2022-01-07 12:28:12 -08:00
Jakub Beránek
047275a682
Add Attribute::meta_kind 2021-12-26 16:56:34 +01:00
bors
a41a6925ba Auto merge of #91957 - nnethercote:rm-SymbolStr, r=oli-obk
Remove `SymbolStr`

This was originally proposed in https://github.com/rust-lang/rust/pull/74554#discussion_r466203544. As well as removing the icky `SymbolStr` type, it allows the removal of a lot of `&` and `*` occurrences.

Best reviewed one commit at a time.

r? `@oli-obk`
2021-12-19 09:31:37 +00:00
Matthias Krüger
eb3cc132d6
Rollup merge of #91896 - pitaj:91867-passes, r=michaelwoerister
Remove `in_band_lifetimes` for `rustc_passes`

#91867
2021-12-18 10:26:36 +01:00
bors
dde825db46 Auto merge of #89841 - cormacrelf:let-else-typed, r=nagisa
Implement let-else type annotations natively

Tracking issue: #87335

Fixes #89688, fixes #89807, edit: fixes  #89960 as well

As explained in https://github.com/rust-lang/rust/issues/89688#issuecomment-940405082, the previous desugaring moved the let-else scrutinee into a dummy variable, which meant if you wanted to refer to it again in the else block, it had moved.

This introduces a new hir type, ~~`hir::LetExpr`~~ `hir::Let`, which takes over all the fields of `hir::ExprKind::Let(...)` and adds an optional type annotation. The `hir::Let` is then treated like a `hir::Local` when type checking a function body, specifically:

* `GatherLocalsVisitor` overrides a new `Visitor::visit_let_expr` and does pretty much exactly what it does for `visit_local`, assigning a local type to the `hir::Let` ~~(they could be deduplicated but they are right next to each other, so at least we know they're the same)~~
* It reuses the code in `check_decl_local` to typecheck the `hir::Let`, simply returning 'bool' for the expression type after doing that.

* ~~`FnCtxt::check_expr_let` passes this local type in to `demand_scrutinee_type`, and then imitates check_decl_local's pattern checking~~
* ~~`demand_scrutinee_type` (the blindest change for me, please give this extra scrutiny) uses this local type instead of of creating a new one~~
    * ~~Just realised the `check_expr_with_needs` was passing NoExpectation further down, need to pass the type there too. And apparently this Expectation API already exists.~~

Some other misc notes:

* ~~Is the clippy code supposed to be autoformatted? I tried not to give huge diffs but maybe some rustfmt changes simply haven't hit it yet.~~
* in `rustc_ast_lowering/src/block.rs`, I noticed some existing `self.alias_attrs()` calls in `LoweringContext::lower_stmts` seem to be copying attributes from the lowered locals/etc to the statements. Is that right? I'm new at this, I don't know.
2021-12-17 22:12:34 +00:00
Peter Jaszkowiak
c4bafafac1 Remove in_band_lifetimes for rustc_passes 2021-12-15 20:12:53 -07:00
Nicholas Nethercote
056d48a2c9 Remove unnecessary sigils around Symbol::as_str() calls. 2021-12-15 17:32:14 +11:00
Matthias Krüger
4e7497bda0
Rollup merge of #91881 - Patrick-Poitras:stabilize-iter-zip, r=scottmcm
Stabilize `iter::zip`

Hello all!

As the tracking issue (#83574) for `iter::zip` completed the final commenting period without any concerns being raised, I hereby submit this stabilization PR on the issue.

As the pull request that introduced the feature (#82917) states, the `iter::zip` function is a shorter way to zip two iterators. As it's generally a quality-of-life/ergonomic improvement, it has been integrated into the codebase without any trouble, and has been
used in many places across the rust compiler and standard library since March without any issues.

For more details, I would refer to `@cuviper's` original PR, or the [function's documentation](https://doc.rust-lang.org/std/iter/fn.zip.html).
2021-12-15 01:28:08 +01:00
Matthias Krüger
272188eecd
Rollup merge of #90939 - estebank:wg-af-polish, r=tmandry
Tweak errors coming from `for`-loop, `?` and `.await` desugaring

 * Suggest removal of `.await` on non-`Future` expression
 * Keep track of obligations introduced by desugaring
 * Remove span pointing at method for obligation errors coming from desugaring
 * Point at called local sync `fn` and suggest making it `async`

```
error[E0277]: `()` is not a future
  --> $DIR/unnecessary-await.rs:9:10
   |
LL |     boo().await;
   |     -----^^^^^^ `()` is not a future
   |     |
   |     this call returns `()`
   |
   = help: the trait `Future` is not implemented for `()`
help: do not `.await` the expression
   |
LL -     boo().await;
LL +     boo();
   |
help: alternatively, consider making `fn boo` asynchronous
   |
LL | async fn boo () {}
   | +++++
```

Fix #66731.
2021-12-15 01:28:04 +01:00
PFPoitras
304ede6bcc Stabilize iter::zip. 2021-12-14 18:50:31 -04:00
Esteban Kuber
b825b0fe63 Fix rebase and clippy tests 2021-12-13 17:09:16 +00:00
Lucas Kent
fae40c5070 Suggest to specify a target triple when eh_personality lang item is missing 2021-12-14 00:04:15 +11:00