Commit Graph

23 Commits

Author SHA1 Message Date
Mu42
20dc532085 Remove Ty::is_region_ptr 2023-03-20 15:32:21 +08:00
Nicholas Nethercote
2200911616 Rename many interner functions.
(This is a large commit. The changes to
`compiler/rustc_middle/src/ty/context.rs` are the most important ones.)

The current naming scheme is a mess, with a mix of `_intern_`, `intern_`
and `mk_` prefixes, with little consistency. In particular, in many
cases it's easy to use an iterator interner when a (preferable) slice
interner is available.

The guiding principles of the new naming system:
- No `_intern_` prefixes.
- The `intern_` prefix is for internal operations.
- The `mk_` prefix is for external operations.
- For cases where there is a slice interner and an iterator interner,
  the former is `mk_foo` and the latter is `mk_foo_from_iter`.

Also, `slice_interners!` and `direct_interners!` can now be `pub` or
non-`pub`, which helps enforce the internal/external operations
division.

It's not perfect, but I think it's a clear improvement.

The following lists show everything that was renamed.

slice_interners
- const_list
  - mk_const_list -> mk_const_list_from_iter
  - intern_const_list -> mk_const_list
- substs
  - mk_substs -> mk_substs_from_iter
  - intern_substs -> mk_substs
  - check_substs -> check_and_mk_substs (this is a weird one)
- canonical_var_infos
  - intern_canonical_var_infos -> mk_canonical_var_infos
- poly_existential_predicates
  - mk_poly_existential_predicates -> mk_poly_existential_predicates_from_iter
  - intern_poly_existential_predicates -> mk_poly_existential_predicates
  - _intern_poly_existential_predicates -> intern_poly_existential_predicates
- predicates
  - mk_predicates -> mk_predicates_from_iter
  - intern_predicates -> mk_predicates
  - _intern_predicates -> intern_predicates
- projs
  - intern_projs -> mk_projs
- place_elems
  - mk_place_elems -> mk_place_elems_from_iter
  - intern_place_elems -> mk_place_elems
- bound_variable_kinds
  - mk_bound_variable_kinds -> mk_bound_variable_kinds_from_iter
  - intern_bound_variable_kinds -> mk_bound_variable_kinds

direct_interners
- region
  - intern_region (unchanged)
- const
  - mk_const_internal -> intern_const
- const_allocation
  - intern_const_alloc -> mk_const_alloc
- layout
  - intern_layout -> mk_layout
- adt_def
  - intern_adt_def -> mk_adt_def_from_data (unusual case, hard to avoid)
  - alloc_adt_def(!) -> mk_adt_def
- external_constraints
  - intern_external_constraints -> mk_external_constraints

Other
- type_list
  - mk_type_list -> mk_type_list_from_iter
  - intern_type_list -> mk_type_list
- tup
  - mk_tup -> mk_tup_from_iter
  - intern_tup -> mk_tup
2023-02-24 07:32:24 +11:00
Nicholas Nethercote
2017aeff88 Use IntoIterator for mk_fn_sig.
This makes a lot of call sites nicer.
2023-02-17 22:24:34 +11:00
Nicholas Nethercote
9d5cf0f0bf Remove the InternIteratorElement impl for &'a T.
`InternIteratorElement` is a trait used to intern values produces by
iterators. There are three impls, corresponding to iterators that
produce different types:
- One for `T`, which operates straightforwardly.
- One for `Result<T, E>`, which is fallible, and will fail early with an
  error result if any of the iterator elements are errors.
- One for `&'a T`, which clones the items as it iterates.

That last one is bad: it's extremely easy to use it without realizing
that it clones, which goes against Rust's normal "explicit is better"
approach to cloning.

So this commit just removes it. In practice, there weren't many use
sites. For all but one of them `into_iter()` could be used, which avoids
the need for cloning. And for the one remaining case `copied()` is
used.
2023-02-17 22:24:34 +11:00
bors
9a7cc6c32f Auto merge of #108127 - matthiaskrgr:rollup-kpzfc6j, r=matthiaskrgr
Rollup of 7 pull requests

Successful merges:

 - #106347 (More accurate spans for arg removal suggestion)
 - #108057 (Prevent some attributes from being merged with others on reexports)
 - #108090 (`if $c:expr { Some($r:expr) } else { None }` =>> `$c.then(|| $r)`)
 - #108092 (note issue for feature(packed_bundled_libs))
 - #108099 (use chars instead of strings where applicable)
 - #108115 (Do not ICE on unmet trait alias bounds)
 - #108125 (Add new people to the compiletest review rotation)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup
2023-02-16 19:21:02 +00:00
Maybe Waffle
8751fa1a9a if $c:expr { Some($r:expr) } else { None } =>> $c.then(|| $r) 2023-02-16 15:26:00 +00:00
Nicholas Nethercote
cef9004f5a Add specialized variants of mk_region.
Much like there are specialized variants of `mk_ty`. This will enable
some optimization in the next commit.

Also rename the existing `re_error*` functions as `mk_re_error*`, for
consistency.
2023-02-15 09:02:44 +11:00
Ralf Jung
1ef16874b5 also do not add noalias on not-Unpin Box 2023-02-06 12:17:41 +01:00
Ralf Jung
ea541bc2ee make &mut !Unpin not dereferenceable
See https://github.com/rust-lang/unsafe-code-guidelines/issues/381 for discussion.
2023-02-06 11:46:37 +01:00
Ralf Jung
201ae73872 make PointerKind directly reflect pointer types
The code that consumes PointerKind (`adjust_for_rust_scalar` in rustc_ty_utils)
ended up using PointerKind variants to talk about Rust reference types (& and
&mut) anyway, making the old code structure quite confusing: one always had to
keep in mind which PointerKind corresponds to which type. So this changes
PointerKind to directly reflect the type.

This does not change behavior.
2023-02-06 11:46:32 +01:00
Kyle Matsuda
c2414dfaa4 change fn_sig query to use EarlyBinder; remove bound_fn_sig query; add EarlyBinder to fn_sig in metadata 2023-01-26 20:28:25 -07:00
Erik Desjardins
009192b01b abi: add AddressSpace field to Primitive::Pointer
...and remove it from `PointeeInfo`, which isn't meant for this.

There are still various places (marked with FIXMEs) that assume all pointers
have the same size and alignment. Fixing this requires parsing non-default
address spaces in the data layout string, which will be done in a followup.
2023-01-22 23:41:39 -05:00
Arpad Borsos
96931a787a
Transform async ResumeTy in generator transform
- Eliminates all the `get_context` calls that async lowering created.
- Replace all `Local` `ResumeTy` types with `&mut Context<'_>`.

The `Local`s that have their types replaced are:
- The `resume` argument itself.
- The argument to `get_context`.
- The yielded value of a `yield`.

The `ResumeTy` hides a `&mut Context<'_>` behind an unsafe raw pointer, and the
`get_context` function is being used to convert that back to a `&mut Context<'_>`.

Ideally the async lowering would not use the `ResumeTy`/`get_context` indirection,
but rather directly use `&mut Context<'_>`, however that would currently
lead to higher-kinded lifetime errors.
See <https://github.com/rust-lang/rust/issues/105501>.

The async lowering step and the type / lifetime inference / checking are
still using the `ResumeTy` indirection for the time being, and that indirection
is removed here. After this transform, the generator body only knows about `&mut Context<'_>`.
2023-01-19 09:03:05 +01:00
Nilstrieb
af23ad93cd Improve comments 2023-01-17 08:14:35 +01:00
Nilstrieb
645c0fddd2 Put noundef on all scalars that don't allow uninit
Previously, it was only put on scalars with range validity invariants
like bool, was uninit was obviously invalid for those.

Since then, we have normatively declared all uninit primitives to be
undefined behavior and can therefore put `noundef` on them.

The remaining concern was the `mem::uninitialized` function, which cause
quite a lot of UB in the older parts of the ecosystem. This function now
doesn't return uninit values anymore, making users of it safe from this
change.

The only real sources of UB where people could encounter uninit
primitives are `MaybeUninit::uninit().assume_init()`, which has always
be clear in the docs about being UB and from heap allocations (like
reading from the spare capacity of a vec. This is hopefully rare enough
to not break anything.
2023-01-17 08:14:35 +01:00
Albert Larsan
40ba0e84d5
Change src/test to tests in source files, fix tidy and tests 2023-01-11 09:32:13 +00:00
Tomasz Miąsko
72f8d6a659 Change type of box_noalias to bool 2023-01-10 10:14:59 +01:00
Tomasz Miąsko
78075e1e26 Change type of mutable_noalias to bool 2023-01-10 10:14:51 +01:00
Erik Desjardins
d165a6d708 cleanup: handle -Zmutable-noalias like -Zbox-noalias 2023-01-04 19:24:42 -05:00
Ralf Jung
e7cad62257 do not add noalias in return position 2023-01-02 15:11:19 +01:00
Arpad Borsos
ecf812777a
Fix Async Generator ABI
This change was missed when making async generators implement `Future` directly.
It did not cause any problems in codegen so far, as `GeneratorState<(), Output>`
happens to have the same ABI as `Poll<Output>`.
2022-12-08 23:27:57 +01:00
Patrick Walton
da630ac79d Introduce deduced parameter attributes, and use them for deducing readonly on
indirect immutable freeze by-value function parameters.

Right now, `rustc` only examines function signatures and the platform ABI when
determining the LLVM attributes to apply to parameters. This results in missed
optimizations, because there are some attributes that can be determined via
analysis of the MIR making up the function body. In particular, `readonly`
could be applied to most indirectly-passed by-value function arguments
(specifically, those that are freeze and are observed not to be mutated), but
it currently is not.

This patch introduces the machinery that allows `rustc` to determine those
attributes. It consists of a query, `deduced_param_attrs`, that, when
evaluated, analyzes the MIR of the function to determine supplementary
attributes. The results of this query for each function are written into the
crate metadata so that the deduced parameter attributes can be applied to
cross-crate functions. In this patch, we simply check the parameter for
mutations to determine whether the `readonly` attribute should be applied to
parameters that are indirect immutable freeze by-value.  More attributes could
conceivably be deduced in the future: `nocapture` and `noalias` come to mind.

Adding `readonly` to indirect function parameters where applicable enables some
potential optimizations in LLVM that are discussed in [issue 103103] and [PR
103070] around avoiding stack-to-stack memory copies that appear in functions
like `core::fmt::Write::write_fmt` and `core::panicking::assert_failed`. These
functions pass a large structure unchanged by value to a subfunction that also
doesn't mutate it. Since the structure in this case is passed as an indirect
parameter, it's a pointer from LLVM's perspective. As a result, the
intermediate copy of the structure that our codegen emits could be optimized
away by LLVM's MemCpyOptimizer if it knew that the pointer is `readonly
nocapture noalias` in both the caller and callee. We already pass `nocapture
noalias`, but we're missing `readonly`, as we can't determine whether a
by-value parameter is mutated by examining the signature in Rust. I didn't have
much success with having LLVM infer the `readonly` attribute, even with fat
LTO; it seems that deducing it at the MIR level is necessary.

No large benefits should be expected from this optimization *now*; LLVM needs
some changes (discussed in [PR 103070]) to more aggressively use the `noalias
nocapture readonly` combination in its alias analysis. I have some LLVM patches
for these optimizations and have had them looked over. With all the patches
applied locally, I enabled LLVM to remove all the `memcpy`s from the following
code:

```rust
fn main() {
    println!("Hello {}", 3);
}
```

which is a significant codegen improvement over the status quo. I expect that
if this optimization kicks in in multiple places even for such a simple
program, then it will apply to Rust code all over the place.

[issue 103103]: https://github.com/rust-lang/rust/issues/103103

[PR 103070]: https://github.com/rust-lang/rust/pull/103070
2022-10-21 02:33:15 -07:00
Cameron Steffen
95b689b1d5 Move utils from rustc_middle to rustc_ty_utils 2022-10-03 09:12:03 -05:00