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Rollup merge of #124251 - scottmcm:unop-ptr-metadata, r=oli-obk

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Add an intrinsic for `ptr::metadata`

The follow-up to #123840, so we can remove `PtrComponents` and `PtrRepr` from libcore entirely (well, after a bootstrap update).

As discussed in <435637808>, this introduces `UnOp::PtrMetadata` taking a raw pointer and returning the associated metadata value.

By no longer going through a `union`, this should also help future PRs better optimize pointer operations.

r? ``@oli-obk``
This commit is contained in:
许杰友 Jieyou Xu (Joe) 2024-05-29 03:25:07 +01:00 • committed by GitHub
commit 2d3b1e014b
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42 changed files with 600 additions and 53 deletions
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17
compiler/rustc_mir_transform/src/lower_intrinsics.rs
View file

@ -316,6 +316,23 @@ impl<'tcx> MirPass<'tcx> for LowerIntrinsics {
terminator.kind = TerminatorKind::Goto { target };
}
sym::ptr_metadata => {
let Ok([ptr]) = <[_; 1]>::try_from(std::mem::take(args)) else {
span_bug!(
terminator.source_info.span,
"Wrong number of arguments for ptr_metadata intrinsic",
);
};
let target = target.unwrap();
block.statements.push(Statement {
source_info: terminator.source_info,
kind: StatementKind::Assign(Box::new((
*destination,
Rvalue::UnaryOp(UnOp::PtrMetadata, ptr.node),
))),
});
terminator.kind = TerminatorKind::Goto { target };
}
_ => {}
}
}

2
compiler/rustc_mir_transform/src/promote_consts.rs
View file

@ -464,7 +464,7 @@ impl<'tcx> Validator<'_, 'tcx> {
Rvalue::UnaryOp(op, operand) => {
match op {
// These operations can never fail.
UnOp::Neg | UnOp::Not => {}
UnOp::Neg | UnOp::Not | UnOp::PtrMetadata => {}
}
self.validate_operand(operand)?;

10
compiler/rustc_mir_transform/src/validate.rs
View file

@ -1109,6 +1109,16 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
ty::Int(..) | ty::Uint(..) | ty::Bool
);
}
UnOp::PtrMetadata => {
if !matches!(self.mir_phase, MirPhase::Runtime(_)) {
// It would probably be fine to support this in earlier phases,
// but at the time of writing it's only ever introduced from intrinsic lowering,
// so earlier things can just `bug!` on it.
self.fail(location, "PtrMetadata should be in runtime MIR only");
}
check_kinds!(a, "Cannot PtrMetadata non-pointer type {:?}", ty::RawPtr(..));
}
}
}
Rvalue::ShallowInitBox(operand, _) => {