Refactor the `MirPass for QualifyAndPromoteConstants`
This is an accumulation of drive-by commits while working on `Vec::new` as a stable `const fn`.
The PR is probably easiest read commit-by-commit.
r? @oli-obk
cc @eddyb @ecstatic-morse -- your two PRs https://github.com/rust-lang/rust/pull/63812 and https://github.com/rust-lang/rust/pull/63860 respectively will conflict with this a tiny bit but it should be trivial to reintegrate your changes atop of this.
Rollup of 11 pull requests
Successful merges:
- #62848 (Use unicode-xid crate instead of libcore)
- #63774 (Fix `window.hashchange is not a function`)
- #63930 (Account for doc comments coming from proc macros without spans)
- #64003 (place: Passing `align` = `layout.align.abi`, when also passing `layout`)
- #64030 (Fix unlock ordering in SGX synchronization primitives)
- #64041 (use TokenStream rather than &[TokenTree] for built-in macros)
- #64051 (Add x86_64-linux-kernel target)
- #64063 (Fix const_err with `-(-0.0)`)
- #64083 (Point at appropriate arm on type error on if/else/match with one non-! arm)
- #64100 (Fix const eval bug breaking run-pass tests in Miri)
- #64157 (Opaque type locations in error message for clarity.)
Failed merges:
r? @ghost
Fix const eval bug breaking run-pass tests in Miri
PR #63580 broke miri's ability to run the run-pass test suite with MIR
optimizations enabled. The issue was that we weren't properly handling
the substs and DefId associated with a Promoted value. This didn't break
anything in rustc because in rustc this code runs before the Inliner
pass which is where the DefId and substs can diverge from their initial
values. It broke Miri though because it ran this code again after
running the optimization pass.
r? @oli-obk
cc @RalfJung
Use unicode-xid crate instead of libcore
This PR proposes to remove `char::is_xid_start` and `char::is_xid_continue` functions from `libcore` and use `unicode_xid` crate from crates.io (note that this crate is already present in rust-lang/rust's Cargo.lock).
Reasons to do this:
* removing rustc-binary-specific stuff from libcore
* making sure that, across the ecosystem, there's a single definition of what rust identifier is (`unicode-xid` has almost 10 million downs, as a `proc_macro2` dependency)
* making it easier to share `rustc_lexer` crate with rust-analyzer: no need to `#[cfg]` if we are building as a part of the compiler
Reasons not to do this:
* increased maintenance burden: we'll need to upgrade unicode version both in libcore and in unicode-xid. However, this shouldn't be a too heavy burden: just running `./unicode.py` after new unicode version. I (@matklad) am ready to be a t-compiler side maintainer of unicode-xid. Moreover, given that xid-unicode is an important dependency of syn, *someone* needs to maintain it anyway.
* xid-unicode implementation is significantly slower. It uses a more compact table with binary search, instead of a trie. However, this shouldn't matter in practice, because we have fast-path for ascii anyway, and code size savings is a plus. Moreover, in #59706 not using libcore turned out to be *faster*, presumably beacause checking for whitespace with match is even faster.
<details>
<summary>old description</summary>
Followup to #59706
r? @eddyb
Note that this doesn't actually remove tables from libcore, to avoid conflict with https://github.com/rust-lang/rust/pull/62641.
cc https://github.com/unicode-rs/unicode-xid/pull/11
</details>
Extend Polonius fact generation for (some) move tracking
This PR will extend rustc to emit facts used for tracking moves and initialization in Polonius. It is most likely the final part of my master's thesis work.
Minimize uses of `LocalInternedString`
`LocalInternedString` is described as "An alternative to `Symbol` and `InternedString`, useful when the chars within the symbol need to be accessed. It is best used for temporary values."
This PR makes the code match that comment, by removing all non-local uses of `LocalInternedString`. This allows the removal of a number of operations on `LocalInternedString` and a couple of uses of `unsafe`.
Add a `Place::is_indirect` method to determine whether a `Place` contains a `Deref` projection
Working on #63860 requires tracking some property about each local. This requires differentiating `Place`s like `x` and `x.field[index]` from ones like `*x` and `*x.field`, since the first two will always access the same region of memory as `x` while the latter two may access any region of memory. This functionality is duplicated in various places across the compiler. This PR adds a helper method to `Place` which determines whether that `Place` has a `Deref` projection at any point and changes some existing code to use the new method.
I've not converted `qualify_consts.rs` to use the new method, since it's not a trivial conversion and it will get replaced anyway by #63860. There may be other potential uses besides the two I change in this PR.
r? @oli-obk
They are only used by rustc_lexer, and are not needed elsewhere.
So we move the relevant definitions into rustc_lexer (while the actual
unicode data comes from the unicode-xid crate) and make the rest of
the compiler use it.
- var_starts_path
- parent
- initialized_at
- moved_out_at
This also switches to the intended emission of `var_drop_used` fact emission,
where that fact is always emitted on a drop-use of a variable, regardless of its
initialization status, as Polonius now handles that.
Make Allocation::bytes private
Fixes#62931.
Direct immutable access to the bytes is still possible but redirected through the new method `raw_bytes_with_undef_and_ptr`, similar to `get_bytes_with_undef_and_ptr` but without requiring an interpretation context and not doing *any* relocation or bounds checks. The `size` of the allocation is stored separately which makes access as `Size` and `usize` more ergonomic.
cc: @RalfJung
PR #63580 broke miri's ability to run the run-pass test suite with MIR
optimizations enabled. The issue was that we weren't properly handling
the substs and DefId associated with a Promoted value. This didn't break
anything in rustc because in rustc this code runs before the Inliner
pass which is where the DefId and substs can diverge from their initial
values. It broke Miri though because it ran this code again after
running the optimization pass.
