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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 <https://rust-lang.zulipchat.com/#narrow/stream/189540-t-compiler.2Fwg-mir-opt/topic/.60ptr_metadata.60.20in.20MIR/near/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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5
compiler/rustc_codegen_ssa/src/mir/operand.rs
View file

@ -565,6 +565,11 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
for elem in place_ref.projection.iter() {
match elem {
mir::ProjectionElem::Field(ref f, _) => {
debug_assert!(
!o.layout.ty.is_any_ptr(),
"Bad PlaceRef: destructing pointers should use cast/PtrMetadata, \
but tried to access field {f:?} of pointer {o:?}",
);
o = o.extract_field(bx, f.index());
}
mir::ProjectionElem::Index(_)

5
compiler/rustc_codegen_ssa/src/mir/place.rs
View file

@ -480,6 +480,11 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
cg_base = match *elem {
mir::ProjectionElem::Deref => bx.load_operand(cg_base).deref(bx.cx()),
mir::ProjectionElem::Field(ref field, _) => {
debug_assert!(
!cg_base.layout.ty.is_any_ptr(),
"Bad PlaceRef: destructing pointers should use cast/PtrMetadata, \
but tried to access field {field:?} of pointer {cg_base:?}",
);
cg_base.project_field(bx, field.index())
}
mir::ProjectionElem::OpaqueCast(ty) => {

34
compiler/rustc_codegen_ssa/src/mir/rvalue.rs
View file

@ -623,19 +623,36 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
mir::Rvalue::UnaryOp(op, ref operand) => {
let operand = self.codegen_operand(bx, operand);
let lloperand = operand.immediate();
let is_float = operand.layout.ty.is_floating_point();
let llval = match op {
mir::UnOp::Not => bx.not(lloperand),
let (val, layout) = match op {
mir::UnOp::Not => {
let llval = bx.not(operand.immediate());
(OperandValue::Immediate(llval), operand.layout)
}
mir::UnOp::Neg => {
if is_float {
bx.fneg(lloperand)
let llval = if is_float {
bx.fneg(operand.immediate())
} else {
bx.neg(lloperand)
bx.neg(operand.immediate())
};
(OperandValue::Immediate(llval), operand.layout)
}
mir::UnOp::PtrMetadata => {
debug_assert!(operand.layout.ty.is_unsafe_ptr());
let (_, meta) = operand.val.pointer_parts();
assert_eq!(operand.layout.fields.count() > 1, meta.is_some());
if let Some(meta) = meta {
(OperandValue::Immediate(meta), operand.layout.field(self.cx, 1))
} else {
(OperandValue::ZeroSized, bx.cx().layout_of(bx.tcx().types.unit))
}
}
};
OperandRef { val: OperandValue::Immediate(llval), layout: operand.layout }
debug_assert!(
val.is_expected_variant_for_type(self.cx, layout),
"Made wrong variant {val:?} for type {layout:?}",
);
OperandRef { val, layout }
}
mir::Rvalue::Discriminant(ref place) => {
@ -718,8 +735,9 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
let values = op.val.immediates_or_place().left_or_else(|p| {
bug!("Field {field_idx:?} is {p:?} making {layout:?}");
});
inputs.extend(values);
let scalars = self.value_kind(op.layout).scalars().unwrap();
debug_assert_eq!(values.len(), scalars.len());
inputs.extend(values);
input_scalars.extend(scalars);
}