This commit adjusts MIR shim construction so that substitutions are
applied to function pointer shims during construction, rather than
during codegen (as determined by `substs_for_mir_body`) - as
substitutions will no longer occur during codegen, function pointer
shims can now be polymorphic without incurring double substitutions.

Signed-off-by: David Wood <david@davidtw.co>

glibc destroys[1] the passed pthread_attr_t if pthread_getattr_np()
fails.  Destroying it again leads to a segfault.  Fix it by only
destroying it on success for glibc.

[1]: https://sourceware.org/git/?p=glibc.git;a=blob;f=nptl/pthread_getattr_np.c;h=ce437205e41dc05653e435f6188768cccdd91c99;hb=HEAD#l205

…ibcs

The calling convention of pthread_getattr_np() is to initialize the
pthread_attr_t, so _destroy() is only necessary on success (and _init()
isn't necessary beforehand).  On the other hand, FreeBSD wants the
attr_t to be initialized before pthread_attr_get_np(), and therefore it
should always be destroyed afterwards.

Make the following methods unstable const under the `const_pin` feature:
- `new`
- `new_unchecked`
- `into_inner`
- `into_inner_unchecked`
- `get_ref`
- `into_ref`

Also adds tests for these methods in a const context.

Tracking issue: rust-lang#76654

Only insert StorageDeads if we actually removed one.
Fixes an issue where we added StorageDead to a place with no StorageLive

This is heavily dependent on MIR inlining running to actually see the drop statement

Co-authored-by: Andreas Jonson <andjo403@users.noreply.github.com>

A significant amount of intrinsics do not actually need backend-specific
behaviors to be implemented, instead relying on methods already in
rustc_codegen_ssa. So, extract those methods out to rustc_codegen_ssa,
so that each backend doesn't need to reimplement the same code.

Use `SyncOnceCell` to only compile it once.
I believe this still adds some kind of locking mechanism?

The use of arith_offset was added in 803e9ae
before the stable wrapper of the intrinsic was available.

https://doc.rust-lang.org/stable/std/intrinsics/fn.arith_offset.html

The latter is on the path to stabilization.

Co-authored-by: est31 <est31@users.noreply.github.com>

This moves build triple discovery for rustbuild from bootstrap.py into a build
script, meaning it will "just work" if building rustbuild via Cargo rather than
Python.

This requires that bootstrap is run from the same worktree as the sources it'll
build, but this is basically required for the build to work anyway. You can
still run it from a different directory, just that the files it builds must be
beside it.

Make the following methods unstable const under the `const_pin` feature:
- `into_ref`
- `get_mut`
- `get_unchecked_mut`

in particular allow a few more promotions for consistency when they were already allowed in other contexts

…nstancedef-fnptrshim, r=nikomatsakis

shim: monomorphic `FnPtrShim`s during construction

Fixes rust-lang#69925.

This PR adjusts MIR shim construction so that substitutions are applied to function pointer shims during construction, rather than during codegen (as determined by `substs_for_mir_body`).

r? @eddyb

…tatic-morse

Some promotion cleanup

Based on top of both rust-lang#75502 and rust-lang#75585, this does some cleanup of the promotion code. The last 2 commits are new.

* Remove the remaining cases where `const fn` is treated different from `fn`. This means no longer promoting ptr-to-int casts, raw ptr operations, and union field accesses in `const fn` -- or anywhere, for that matter. These are all unstable in const-context so this should not break any stable code. Fixes rust-lang#75586.
* ~~Promote references to statics even outside statics (i.e., in functions) for consistency.~~
* Promote `&mut []` everywhere, not just in non-`const` functions, for consistency.
* Explain why we do not promote deref's of statics outside statics. ~~(This is the only remaining direct user of `const_kind`.)~~

This can only land once the other two PRs land; I am mostly putting this up already because I couldn't wait ;) and to get some feedback from @rust-lang/wg-const-eval .

…roy, r=Amanieu

Fix segfault if pthread_getattr_np fails

glibc [destroys][1] the passed pthread_attr_t if pthread_getattr_np()
fails.  Destroying it again leads to a segfault.  Fix it by only
destroying it on success for glibc.

[1]: https://sourceware.org/git/?p=glibc.git;a=blob;f=nptl/pthread_getattr_np.c;h=ce437205e41dc05653e435f6188768cccdd91c99;hb=HEAD#l205

…crichton

De-couple Python and bootstrap slightly

This revises rustbuild's entry points from Python to rely less on magic environment variables, preferring to use Cargo-provided environment variables where feasible.

Notably, BUILD_DIR and BOOTSTRAP_CONFIG are *not* moved, because both more-or-less have some non-trivial discovery logic and replicating it in rustbuild seems unfortunate; if it moved to Cargo that would be a different story.

Best reviewed by-commit.

Make some methods of `Pin` unstable const

Make the following methods unstable const under the `const_pin` feature:
- `new`
- `new_unchecked`
- `into_inner`
- `into_inner_unchecked`
- `get_ref`
- `into_ref`
- `get_mut`
- `get_unchecked_mut`

Of these, `into_inner` and `into_inner_unchecked` require the unstable `const_precise_live_drops`.

Also adds tests for these methods in a const context.

Tracking issue: rust-lang#76654

r? @ecstatic-morse

SimplifyComparisonIntegral: fix miscompilation

Fixes rust-lang#76432
Only insert StorageDeads if we actually removed one.
Fixes an issue where we added StorageDead to a place with no StorageLive

r? @oli-obk

…r=oli-obk

MIR pass to remove unneeded drops on types not needing drop

This is heavily dependent on MIR inlining running to actually see the drop statement.

Do we want to special case replacing a call to std::mem::drop with a goto aswell?

…ulacrum

Test and fix Send and Sync traits of BTreeMap artefacts

Fixes rust-lang#76686.

I'm not quite sure what all this implies. E.g. comparing with the definitions for `NodeRef` in node.rs,  maybe an extra bound `T: 'a` is useful for something. The test compiles on stable/beta (apart from `drain_filter`) so I bet `Sync` is equally desirable.

r? @Mark-Simulacrum

…tatic-morse

Clean up diagnostics for arithmetic operation errors

Plus a small tweak to a range pattern error message.

Extract some intrinsics out of rustc_codegen_llvm

A significant amount of intrinsics do not actually need backend-specific behaviors to be implemented, instead relying on methods already in rustc_codegen_ssa. So, extract those methods out to rustc_codegen_ssa, so that each backend doesn't need to reimplement the same code.

Almost everything should be a pretty direct translation. A notable not-direct-translation is `add_with_overflow` and friends being changed to `bx.checked_binop`, but it's pretty simple.

I could have been a lot more aggressive here and pulled out way more methods, and add a few new methods in the rustc_codegen_ssa "API". However, because this is my second rustc PR, I thought that moving those to a follow-up PR and doing more incremental changes here would be better (and I guess ask if this work is even desired in the first place). I'm hoping to eventually remove the mess of intrinsic handling in the backend entirely, which would be hecking fantastic ✨

Only get ImplKind::Impl once

With this, the code panics in one place instead of two.

simplfy condition in ItemLowerer::with_trait_impl_ref()

Fix wording in mir doc

…me, r=ecstatic-morse

Don't compile regex at every function call.

Use `SyncOnceCell` to only compile it once.
I believe this still adds some kind of locking mechanism?

Related issue: rust-lang#76817

…ures, r=oli-obk,Mark-Simulacrum

Remove redundant nightly features

Removes a bunch of redundant/outdated nightly features. The first commit removes a `core_intrinsics` use for which a stable wrapper has been provided since. The second commit replaces the `const_generics` feature with `min_const_generics` which might get stabilized this year. The third commit is the result of a trial/error run of removing every single feature and then adding it back if compile failed. A bunch of unused features are the result that the third commit removes.

…lett

black_box: silence unused_mut warning when building with cfg(miri)

use `array_windows` instead of `windows` in the compiler

I do think these changes are beautiful, but do have to admit that using type inference for the window length
can easily be confusing. This seems like a general issue with const generics, where inferring constants adds an additional
complexity which users have to learn and keep in mind.

…hievink

fix array_windows docs

r? @Dylan-DPC