All derive ops currently use match-destructuring to access fields. This
is reasonable for enums, but sub-optimal for structs. E.g.:
```
fn eq(&self, other: &Point) -> bool {
match *other {
Self { x: ref __self_1_0, y: ref __self_1_1 } =>
match *self {
Self { x: ref __self_0_0, y: ref __self_0_1 } =>
(*__self_0_0) == (*__self_1_0) &&
(*__self_0_1) == (*__self_1_1),
},
}
}
```
This commit changes derive ops on structs to use field access instead, e.g.:
```
fn eq(&self, other: &Point) -> bool {
self.x == other.x && self.y == other.y
}
```
This is faster to compile, results in smaller binaries, and is simpler to
generate. Unfortunately, we have to keep the old pattern generating code around
for `repr(packed)` structs because something like `&self.x` (which doesn't show
up in `PartialEq` ops, but does show up in `Debug` and `Hash` ops) isn't
allowed. But this commit at least changes those cases to use let-destructuring
instead of match-destructuring, e.g.:
```
fn hash<__H: ::core:#️⃣:Hasher>(&self, state: &mut __H) -> () {
{
let Self(ref __self_0_0) = *self;
{ ::core:#️⃣:Hash::hash(&(*__self_0_0), state) }
}
}
```
There are some unnecessary blocks remaining in the generated code, but I
will fix them in a follow-up PR.
The existing derive code allows for various possibilities that aren't
needed in practice, which complicates the code. There are only a few
auto-derived traits and new ones are unlikely, so this commit simplifies
things.
- `PtrTy` has been eliminated. The `Raw` variant was never used, and the
lifetime for the `Borrowed` variant was always `None`. That left just
the mutability field, which has been inlined as necessary.
- `MethodDef::explicit_self` was a confusing `Option<Option<PtrTy>>`.
Indicating either `&self` or nothing. It's now a `bool`.
- `borrowed_self` is renamed as `self_ref`.
- `Ty::Ptr` is renamed to `Ty::Ref`.
The `&[ast::Variant]` field isn't used.
The `Vec<Ident>` field is only used for its length, but that's always
the same as the length of the `&[Ident]` and so isn't necessary.
[RFC 2011] Optimize non-consuming operators
Tracking issue: https://github.com/rust-lang/rust/issues/44838
Fifth step of https://github.com/rust-lang/rust/pull/96496
The most non-invasive approach that will probably have very little to no performance impact.
## Current behaviour
Captures are handled "on-the-fly", i.e., they are performed in the same place expressions are located.
```rust
// `let a = 1; let b = 2; assert!(a > 1 && b < 100);`
if !(
{ ***try capture `a` and then return `a`*** } > 1 && { ***try capture `b` and then return `b`*** } < 100
) {
panic!( ... );
}
```
As such, some overhead is likely to occur (Specially with very large chains of conditions).
## New behaviour for non-consuming operators
When an operator is known to not take `self`, then it is possible to capture variables **AFTER** the condition.
```rust
// `let a = 1; let b = 2; assert!(a > 1 && b < 100);`
if !( a > 1 && b < 100 ) {
{ ***try capture `a`*** }
{ ***try capture `b`*** }
panic!( ... );
}
```
So the possible impact on the runtime execution time will be diminished.
r? ````@oli-obk````
Currently the generated code for methods like `eq`, `ne`, and `partial_cmp`
includes stuff like this:
```
let __self_vi = ::core::intrinsics::discriminant_value(&*self);
let __arg_1_vi = ::core::intrinsics::discriminant_value(&*other);
if true && __self_vi == __arg_1_vi {
...
}
```
This commit removes the unnecessary `true &&`, and makes the generating
code a little easier to read in the process. It also fixes some errors
in comments.
macros: use typed identifiers in diag and subdiag derive
Using typed identifiers instead of strings with the Fluent identifiers in the diagnostic and subdiagnostic derives - this enables the diagnostic derive to benefit from the compile-time validation that comes with typed identifiers, namely that use of a non-existent Fluent identifier will not compile.
r? `````@oli-obk`````
Using typed identifiers instead of strings with the Fluent identifier
enables the diagnostic derive to benefit from the compile-time
validation that comes with typed identifiers - use of a non-existent
Fluent identifier will not compile.
Signed-off-by: David Wood <david.wood@huawei.com>
Fixup missing renames from `#[main]` to `#[rustc_main]`
In #84217 `#[main]` was removed and replaced with `#[rustc_main]`. In some places the rename was forgotten, which makes the current code confusing, because at first glance it seems that `#[main]` is still around. Perform the renames also in these places.
I noticed this (after first being confused by it) when working on #97802.
r? `@petrochenkov`
(since you reviewed the other PR)
This commit adds new methods that combine sequences of existing
formatting methods.
- `Formatter::debug_{tuple,struct}_field[12345]_finish`, equivalent to a
`Formatter::debug_{tuple,struct}` + N x `Debug{Tuple,Struct}::field` +
`Debug{Tuple,Struct}::finish` call sequence.
- `Formatter::debug_{tuple,struct}_fields_finish` is similar, but can
handle any number of fields by using arrays.
These new methods are all marked as `doc(hidden)` and unstable. They are
intended for the compiler's own use.
Special-casing up to 5 fields gives significantly better performance
results than always using arrays (as was tried in #95637).
The commit also changes the `Debug` deriving code to use these new methods. For
example, where the old `Debug` code for a struct with two fields would be like
this:
```
fn fmt(&self, f: &mut ::core::fmt::Formatter) -> ::core::fmt::Result {
match *self {
Self {
f1: ref __self_0_0,
f2: ref __self_0_1,
} => {
let debug_trait_builder = &mut ::core::fmt::Formatter::debug_struct(f, "S2");
let _ = ::core::fmt::DebugStruct::field(debug_trait_builder, "f1", &&(*__self_0_0));
let _ = ::core::fmt::DebugStruct::field(debug_trait_builder, "f2", &&(*__self_0_1));
::core::fmt::DebugStruct::finish(debug_trait_builder)
}
}
}
```
the new code is like this:
```
fn fmt(&self, f: &mut ::core::fmt::Formatter) -> ::core::fmt::Result {
match *self {
Self {
f1: ref __self_0_0,
f2: ref __self_0_1,
} => ::core::fmt::Formatter::debug_struct_field2_finish(
f,
"S2",
"f1",
&&(*__self_0_0),
"f2",
&&(*__self_0_1),
),
}
}
```
This shrinks the code produced for `Debug` instances
considerably, reducing compile times and binary sizes.
Co-authored-by: Scott McMurray <scottmcm@users.noreply.github.com>
In fc357039f9 `#[main]` was removed and replaced with `#[rustc_main]`.
In some place the rename was forgotten, which makes the current code
confusing, because at first glance it seems that `#[main]` is still
around. Perform the renames also in these places.
proc_macro: don't pass a client-side function pointer through the server.
Before this PR, `proc_macro::bridge::Client<F>` contained both:
* the C ABI entry-point `run`, that the server can call to start the client
* some "payload" `f: F` passed to that entry-point
* in practice, this was always a (client-side Rust ABI) `fn` pointer to the actual function the proc macro author wrote, i.e. `#[proc_macro] fn foo(input: TokenStream) -> TokenStream`
In other words, the client was passing one of its (Rust) `fn` pointers to the server, which was passing it back to the client, for the client to call (see later below for why that was ever needed).
I was inspired by `@nnethercote's` attempt to remove the `get_handle_counters` field from `Client` (see https://github.com/rust-lang/rust/pull/97004#issuecomment-1139273301), which combined with removing the `f` ("payload") field, could theoretically allow for a `#[repr(transparent)]` `Client` that mostly just newtypes the C ABI entry-point `fn` pointer <sub>(and in the context of e.g. wasm isolation, that's *all* you want, since you can reason about it from outside the wasm VM, as just a 32-bit "function table index", that you can pass to the wasm VM to call that function)</sub>.
<hr/>
So this PR removes that "payload". But it's not a simple refactor: the reason the field existed in the first place is because monomorphizing over a function type doesn't let you call the function without having a value of that type, because function types don't implement anything like `Default`, i.e.:
```rust
extern "C" fn ffi_wrapper<A, R, F: Fn(A) -> R>(arg: A) -> R {
let f: F = ???; // no way to get a value of `F`
f(arg)
}
```
That could be solved with something like this, if it was allowed:
```rust
extern "C" fn ffi_wrapper<
A, R,
F: Fn(A) -> R,
const f: F // not allowed because the type is a generic param
>(arg: A) -> R {
f(arg)
}
```
Instead, this PR contains a workaround in `proc_macro::bridge::selfless_reify` (see its module-level comment for more details) that can provide something similar to the `ffi_wrapper` example above, but limited to `F` being `Copy` and ZST (and requiring an `F` value to prove the caller actually can create values of `F` and it's not uninhabited or some other unsound situation).
<hr/>
Hopefully this time we don't have a performance regression, and this has a chance to land.
cc `@mystor` `@bjorn3`
Begin fixing all the broken doctests in `compiler/`
Begins to fix#95994.
All of them pass now but 24 of them I've marked with `ignore HELP (<explanation>)` (asking for help) as I'm unsure how to get them to work / if we should leave them as they are.
There are also a few that I marked `ignore` that could maybe be made to work but seem less important.
Each `ignore` has a rough "reason" for ignoring after it parentheses, with
- `(pseudo-rust)` meaning "mostly rust-like but contains foreign syntax"
- `(illustrative)` a somewhat catchall for either a fragment of rust that doesn't stand on its own (like a lone type), or abbreviated rust with ellipses and undeclared types that would get too cluttered if made compile-worthy.
- `(not-rust)` stuff that isn't rust but benefits from the syntax highlighting, like MIR.
- `(internal)` uses `rustc_*` code which would be difficult to make work with the testing setup.
Those reason notes are a bit inconsistently applied and messy though. If that's important I can go through them again and try a more principled approach. When I run `rg '```ignore \(' .` on the repo, there look to be lots of different conventions other people have used for this sort of thing. I could try unifying them all if that would be helpful.
I'm not sure if there was a better existing way to do this but I wrote my own script to help me run all the doctests and wade through the output. If that would be useful to anyone else, I put it here: https://github.com/Elliot-Roberts/rust_doctest_fixing_tool
Add a new Rust attribute to support embedding debugger visualizers
Implemented [this RFC](https://github.com/rust-lang/rfcs/pull/3191) to add support for embedding debugger visualizers into a PDB.
Added a new attribute `#[debugger_visualizer]` and updated the `CrateMetadata` to store debugger visualizers for crate dependencies.
RFC: https://github.com/rust-lang/rfcs/pull/3191
