Optimize matches
Attempt to fix or improve #60571
This is breaking some diagnostics because the MIR for match arms isn't in source order any more.
cc @centril
Remove some unnecessary symbol interner ops
* Don't gensym symbols that don't need to worry about colliding with other symbols
* Use symbol constants instead of interning string literals in a few places.
* Don't generate a module in `__register_diagnostic`
r? @petrochenkov
Allow attributes in formal function parameters
Implements https://github.com/rust-lang/rust/issues/60406.
This is my first contribution to the compiler and since this is a large and complex project, I am not fully aware of the consequences of the changes I have made.
**TODO**
- [x] Forbid some built-in attributes.
- [x] Expand cfg/cfg_attr
Use Symbol, Span in libfmt_macros
I'm not super happy with this, personally, but I think it might be a decent start -- happy to take suggestions as to how to expand this or change things further.
r? @estebank
Fixes#60795
Make tuple constructors real const fns
Mir construction special cases `Ctor(...)` to be lowered as `Ctor { 0: ... }`, which means this doesn't come up much in practice, but it seems inconsistent not to allow this.
r? @oli-obk
Simplify use of keyword symbols
They mirror non-keyword symbols now (see https://github.com/rust-lang/rust/pull/60630).
`keywords::MyKeyword.name()` -> `kw::MyKeyword`
`keywords::MyKeyword.ident()` -> `Ident::with_empty_ctxt(kw::MyKeyword)` (not common)
`keywords::Invalid.ident()` -> `Ident::invalid()` (more common)
Keywords are simply `Symbol` constants now, the `Keyword` struct is eliminated.
This means `kw::MyKeyword` can now be used in `match` in particular.
This allows types like Option<NonZeroU8> to be used in FFI without triggering the improper_ctypes lint. This works by changing the is_repr_nullable_ptr function to consider an enum E to be FFI-safe if:
- E has no explicit #[repr(...)].
- It only has two variants.
- One of those variants is empty (meaning it has no fields).
- The other variant has only one field.
- That field is one of the following:
- &T
- &mut T
- extern "C" fn
- core::num::NonZero*
- core::ptr::NonNull<T>
- #[repr(transparent)] struct wrapper around one of the types in this list.
- The size of E and its field are both known and are both the same size (implying E is participating in the nonnull optimization).
Remove impls for `InternedString`/string equality.
`Symbol` received the same treatment in #60630.
Also, we can derive `PartialEq` for `InternedString`.
r? @petrochenkov
Move gensym operations from `Symbol` to `Ident`
Gensyms are always at the `Ident` level, and long-term we probably want to record gensym-ness in hygiene data.
r? @petrochenkov
Note that the `is_gensymed` call on `primitive_types` is unnecessary
because that table only contains the name of primitive types (e.g.
`i32`) and never contains gensyms.
Use `Symbol` even more
These patches simplify the code a bit (fewer conversions) and also speed things up a bit (fewer `with_interner` calls).
r? @petrochenkov
`LocalInternedString::intern(x)` is preferable to
`Symbol::intern(x).as_str()`, because the former involves one call to
`with_interner` while the latter involves two.
`InternedString::intern(x)` is preferable to
`Symbol::intern(x).as_interned_str()`, because the former involves one
call to `with_interner` while the latter involves two.
The case within InternedString::decode() is particularly hot, and this
change reduces the number of `with_interner` calls by up to 13%.
These will be used in the subsequent commits. Many of them are
attributes.
The commit also adds the ability to handle symbols that aren't
identifiers (e.g. "proc-macro").
Adds support for .await under the existing async_await feature gate.
Moves macro-like await! syntax to the await_macro feature gate.
Removes support for `await` as a non-keyword under the `async_await`
feature.
Use a `newtype_index!` within `Symbol`.
This shrinks `Option<Symbol>` from 8 bytes to 4 bytes, which shrinks
`Token` from 24 bytes to 16 bytes. This reduces instruction counts by up
to 1% across a range of benchmarks.
r? @oli-obk
* Update bootstrap compiler
* Update version to 1.33.0
* Remove some `#[cfg(stage0)]` annotations
Actually updating the version number is blocked on updating Cargo
This shrinks `Option<Symbol>` from 8 bytes to 4 bytes, which shrinks
`Token` from 24 bytes to 16 bytes. This reduces instruction counts by up
to 1% across a range of benchmarks.
`CrateRoot` -> `PathRoot`, `::` doesn't necessarily mean crate root now
`SelfValue` -> `SelfLower`, `SelfType` -> `SelfUpper`, both `self` and `Self` can be used in type and value namespaces now
`Printer::word` takes a `&str` and converts it into a `String`, which
causes an allocation. But that allocation is rarely necessary, because
`&str` is almost always a `&'static str` or a `String` that won't be
used again.
This commit changes `Token::String` so it holds a `Cow<'static, str>`
instead of a `String`, which avoids a lot of allocations.
