bjoernager/rust
bjoernager/rust
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remove box derefs from codgen

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This commit is contained in:
DrMeepster 2022-05-13 21:53:03 -07:00
parent 3e9d3d917a
commit cb417881a9
16 changed files with 385 additions and 146 deletions
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14
compiler/rustc_codegen_ssa/src/mir/operand.rs
View file

@ -118,22 +118,20 @@ impl<'a, 'tcx, V: CodegenObject> OperandRef<'tcx, V> {
}
pub fn deref<Cx: LayoutTypeMethods<'tcx>>(self, cx: &Cx) -> PlaceRef<'tcx, V> {
if self.layout.ty.is_box() && !self.layout.abi.is_scalar() {
bug!("dereferencing non-scalar box ({:?}) in codegen", self.layout.ty);
}
let projected_ty = self
.layout
.ty
.builtin_deref(true)
.unwrap_or_else(|| bug!("deref of non-pointer {:?}", self))
.ty;
let (llptr, llextra) = match self.val {
OperandValue::Immediate(llptr) => (llptr, None),
OperandValue::Pair(llptr, llextra) => {
// if the box's allocator isn't a ZST, then "llextra" is actually the allocator
if self.layout.ty.is_box() && !self.layout.field(cx, 1).is_zst() {
(llptr, None)
} else {
(llptr, Some(llextra))
}
}
OperandValue::Pair(llptr, llextra) => (llptr, Some(llextra)),
OperandValue::Ref(..) => bug!("Deref of by-Ref operand {:?}", self),
};
let layout = cx.layout_of(projected_ty);

24
compiler/rustc_codegen_ssa/src/mir/place.rs
View file

@ -446,16 +446,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
mir::PlaceRef { projection: &place_ref.projection[..elem.0], ..place_ref },
);
// a box with a non-zst allocator should not be directly dereferenced
if cg_base.layout.ty.is_box() && !cg_base.layout.field(cx, 1).is_zst() {
// Extract `Box<T>` -> `Unique<T>` -> `NonNull<T>` -> `*const T`
let ptr =
cg_base.extract_field(bx, 0).extract_field(bx, 0).extract_field(bx, 0);
ptr.deref(bx.cx())
} else {
cg_base.deref(bx.cx())
}
cg_base.deref(bx.cx())
} else {
bug!("using operand local {:?} as place", place_ref);
}
@ -463,18 +454,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
};
for elem in place_ref.projection[base..].iter() {
cg_base = match *elem {
mir::ProjectionElem::Deref => {
// a box with a non-zst allocator should not be directly dereferenced
if cg_base.layout.ty.is_box() && !cg_base.layout.field(cx, 1).is_zst() {
// Project `Box<T>` -> `Unique<T>` -> `NonNull<T>` -> `*const T`
let ptr =
cg_base.project_field(bx, 0).project_field(bx, 0).project_field(bx, 0);
bx.load_operand(ptr).deref(bx.cx())
} else {
bx.load_operand(cg_base).deref(bx.cx())
}
}
mir::ProjectionElem::Deref => bx.load_operand(cg_base).deref(bx.cx()),
mir::ProjectionElem::Field(ref field, _) => {
cg_base.project_field(bx, field.index())
}