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Call destructors when dyn* object goes out of scope

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This commit is contained in:
Eric Holk 2022-07-27 14:50:11 -07:00
parent 549c105bb3
commit c5441acf67
8 changed files with 59 additions and 18 deletions
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3
compiler/rustc_codegen_ssa/src/meth.rs
View File

@ -86,6 +86,7 @@ fn expect_dyn_trait_in_self<'tcx>(ty: Ty<'tcx>) -> ty::PolyExistentialTraitRef<'
/// The `trait_ref` encodes the erased self type. Hence if we are
/// making an object `Foo<dyn Trait>` from a value of type `Foo<T>`, then
/// `trait_ref` would map `T: Trait`.
#[instrument(level = "debug", skip(cx))]
pub fn get_vtable<'tcx, Cx: CodegenMethods<'tcx>>(
cx: &Cx,
ty: Ty<'tcx>,
@ -93,8 +94,6 @@ pub fn get_vtable<'tcx, Cx: CodegenMethods<'tcx>>(
) -> Cx::Value {
let tcx = cx.tcx();
debug!("get_vtable(ty={:?}, trait_ref={:?})", ty, trait_ref);
// Check the cache.
if let Some(&val) = cx.vtables().borrow().get(&(ty, trait_ref)) {
return val;

24
compiler/rustc_codegen_ssa/src/mir/block.rs
View File

@ -16,7 +16,7 @@ use rustc_index::vec::Idx;
use rustc_middle::mir::{self, AssertKind, SwitchTargets};
use rustc_middle::ty::layout::{HasTyCtxt, LayoutOf};
use rustc_middle::ty::print::{with_no_trimmed_paths, with_no_visible_paths};
use rustc_middle::ty::{self, Instance, Ty, TypeVisitable, TraitObjectRepresentation};
use rustc_middle::ty::{self, Instance, TraitObjectRepresentation, Ty, TypeVisitable};
use rustc_span::source_map::Span;
use rustc_span::{sym, Symbol};
use rustc_symbol_mangling::typeid::typeid_for_fnabi;
@ -451,7 +451,27 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
// (data, vtable) // an equivalent Rust `*mut dyn Trait`
//
// SO THEN WE CAN USE THE ABOVE CODE.
todo!()
let virtual_drop = Instance {
def: ty::InstanceDef::Virtual(drop_fn.def_id(), 0),
substs: drop_fn.substs,
};
debug!("ty = {:?}", ty);
debug!("drop_fn = {:?}", drop_fn);
debug!("args = {:?}", args);
let fn_abi = bx.fn_abi_of_instance(virtual_drop, ty::List::empty());
let data = args[0];
let data_ty = bx.cx().backend_type(place.layout);
let vtable_ptr =
bx.gep(data_ty, data, &[bx.cx().const_i32(0), bx.cx().const_i32(1)]);
let vtable = bx.load(bx.type_i8p(), vtable_ptr, abi::Align::ONE);
// Truncate vtable off of args list
args = &args[..1];
debug!("args' = {:?}", args);
(
meth::VirtualIndex::from_index(ty::COMMON_VTABLE_ENTRIES_DROPINPLACE)
.get_fn(&mut bx, vtable, ty, &fn_abi),
fn_abi,
)
}
_ => (bx.get_fn_addr(drop_fn), bx.fn_abi_of_instance(drop_fn, ty::List::empty())),
};

13
compiler/rustc_codegen_ssa/src/mir/rvalue.rs
View File

@ -4,6 +4,7 @@ use super::{FunctionCx, LocalRef};
use crate::base;
use crate::common::{self, IntPredicate};
use crate::meth::get_vtable;
use crate::traits::*;
use crate::MemFlags;
@ -11,6 +12,7 @@ use rustc_middle::mir;
use rustc_middle::mir::Operand;
use rustc_middle::ty::cast::{CastTy, IntTy};
use rustc_middle::ty::layout::{HasTyCtxt, LayoutOf};
use rustc_middle::ty::TraitObjectRepresentation;
use rustc_middle::ty::{self, adjustment::PointerCast, Instance, Ty, TyCtxt};
use rustc_span::source_map::{Span, DUMMY_SP};
@ -271,14 +273,19 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
bug!("unexpected non-pair operand");
}
}
#[allow(unreachable_code, unused)] // FIXME: remove this
mir::CastKind::DynStar => {
let data = match operand.val {
OperandValue::Ref(_, _, _) => todo!(),
OperandValue::Immediate(_) => todo!(),
OperandValue::Immediate(v) => v,
OperandValue::Pair(_, _) => todo!(),
};
let vtable = todo!();
// FIXME: find the real vtable!
let trait_ref = if let ty::Dynamic(data, _, TraitObjectRepresentation::Sized) = cast.ty.kind() {
data.principal()
} else {
bug!("Only valid to do a DynStar cast into a DynStar type")
};
let vtable = get_vtable(bx.cx(), source.ty(self.mir, bx.tcx()), trait_ref);
OperandValue::Pair(data, vtable)
}
mir::CastKind::Pointer(

15
compiler/rustc_middle/src/ty/layout.rs
View File

@ -2751,6 +2751,7 @@ impl<'tcx> ty::Instance<'tcx> {
// for `Instance` (e.g. typeck would use `Ty::fn_sig` instead),
// or should go through `FnAbi` instead, to avoid losing any
// adjustments `fn_abi_of_instance` might be performing.
#[tracing::instrument(level = "debug", skip(tcx, param_env))]
fn fn_sig_for_fn_abi(
&self,
tcx: TyCtxt<'tcx>,
@ -2897,6 +2898,7 @@ impl<'tcx> ty::Instance<'tcx> {
/// with `-Cpanic=abort` will look like they can't unwind when in fact they
/// might (from a foreign exception or similar).
#[inline]
#[tracing::instrument(level = "debug", skip(tcx))]
pub fn fn_can_unwind<'tcx>(tcx: TyCtxt<'tcx>, fn_def_id: Option<DefId>, abi: SpecAbi) -> bool {
if let Some(did) = fn_def_id {
// Special attribute for functions which can't unwind.
@ -3113,6 +3115,7 @@ pub trait FnAbiOf<'tcx>: FnAbiOfHelpers<'tcx> {
/// NB: that includes virtual calls, which are represented by "direct calls"
/// to an `InstanceDef::Virtual` instance (of `<dyn Trait as Trait>::fn`).
#[inline]
#[tracing::instrument(level = "debug", skip(self))]
fn fn_abi_of_instance(
&self,
instance: ty::Instance<'tcx>,
@ -3259,6 +3262,10 @@ pub fn adjust_for_rust_scalar<'tcx>(
impl<'tcx> LayoutCx<'tcx, TyCtxt<'tcx>> {
// FIXME(eddyb) perhaps group the signature/type-containing (or all of them?)
// arguments of this method, into a separate `struct`.
#[tracing::instrument(
level = "debug",
skip(self, caller_location, fn_def_id, force_thin_self_ptr)
)]
fn fn_abi_new_uncached(
&self,
sig: ty::PolyFnSig<'tcx>,
@ -3268,8 +3275,6 @@ impl<'tcx> LayoutCx<'tcx, TyCtxt<'tcx>> {
// FIXME(eddyb) replace this with something typed, like an `enum`.
force_thin_self_ptr: bool,
) -> Result<&'tcx FnAbi<'tcx, Ty<'tcx>>, FnAbiError<'tcx>> {
debug!("fn_abi_new_uncached({:?}, {:?})", sig, extra_args);
let sig = self.tcx.normalize_erasing_late_bound_regions(self.param_env, sig);
let conv = conv_from_spec_abi(self.tcx(), sig.abi);
@ -3312,6 +3317,8 @@ impl<'tcx> LayoutCx<'tcx, TyCtxt<'tcx>> {
let rust_abi = matches!(sig.abi, RustIntrinsic | PlatformIntrinsic | Rust | RustCall);
let arg_of = |ty: Ty<'tcx>, arg_idx: Option<usize>| -> Result<_, FnAbiError<'tcx>> {
let span = tracing::debug_span!("arg_of");
let _entered = span.enter();
let is_return = arg_idx.is_none();
let layout = self.layout_of(ty)?;
@ -3368,6 +3375,7 @@ impl<'tcx> LayoutCx<'tcx, TyCtxt<'tcx>> {
Ok(self.tcx.arena.alloc(fn_abi))
}
#[tracing::instrument(level = "debug", skip(self))]
fn fn_abi_adjust_for_abi(
&self,
fn_abi: &mut FnAbi<'tcx, Ty<'tcx>>,
@ -3442,6 +3450,7 @@ impl<'tcx> LayoutCx<'tcx, TyCtxt<'tcx>> {
}
}
#[tracing::instrument(level = "debug", skip(cx))]
fn make_thin_self_ptr<'tcx>(
cx: &(impl HasTyCtxt<'tcx> + HasParamEnv<'tcx>),
layout: TyAndLayout<'tcx>,
@ -3453,7 +3462,7 @@ fn make_thin_self_ptr<'tcx>(
tcx.mk_mut_ptr(layout.ty)
} else {
match layout.abi {
Abi::ScalarPair(..) => (),
Abi::ScalarPair(..) | Abi::Scalar(..) => (),
_ => bug!("receiver type has unsupported layout: {:?}", layout),
}

2
compiler/rustc_middle/src/ty/normalize_erasing_regions.rs
View File

@ -36,6 +36,7 @@ impl<'tcx> TyCtxt<'tcx> {
///
/// This should only be used outside of type inference. For example,
/// it assumes that normalization will succeed.
#[tracing::instrument(level = "debug", skip(self, param_env))]
pub fn normalize_erasing_regions<T>(self, param_env: ty::ParamEnv<'tcx>, value: T) -> T
where
T: TypeFoldable<'tcx>,
@ -100,6 +101,7 @@ impl<'tcx> TyCtxt<'tcx> {
/// N.B., currently, higher-ranked type bounds inhibit
/// normalization. Therefore, each time we erase them in
/// codegen, we need to normalize the contents.
#[tracing::instrument(level = "debug", skip(self, param_env))]
pub fn normalize_erasing_late_bound_regions<T>(
self,
param_env: ty::ParamEnv<'tcx>,

5
compiler/rustc_mir_build/src/build/expr/as_rvalue.rs
View File

@ -216,10 +216,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
};
let from_ty = CastTy::from_ty(ty);
let cast_ty = CastTy::from_ty(expr.ty);
debug!(
"ExprKind::Cast from_ty={from_ty:?}, cast_ty={:?}/{cast_ty:?}",
expr.ty,
);
debug!("ExprKind::Cast from_ty={from_ty:?}, cast_ty={:?}/{cast_ty:?}", expr.ty,);
let cast_kind = match (from_ty, cast_ty) {
(Some(CastTy::Ptr(_) | CastTy::FnPtr), Some(CastTy::Int(_))) => {
CastKind::PointerExposeAddress

13
compiler/rustc_monomorphize/src/collector.rs
View File

@ -189,7 +189,8 @@ use rustc_middle::ty::adjustment::{CustomCoerceUnsized, PointerCast};
use rustc_middle::ty::print::with_no_trimmed_paths;
use rustc_middle::ty::subst::{GenericArgKind, InternalSubsts};
use rustc_middle::ty::{
self, GenericParamDefKind, Instance, Ty, TyCtxt, TypeFoldable, TypeVisitable, VtblEntry,
self, GenericParamDefKind, Instance, TraitObjectRepresentation, Ty, TyCtxt, TypeFoldable,
TypeVisitable, VtblEntry,
};
use rustc_middle::{middle::codegen_fn_attrs::CodegenFnAttrFlags, mir::visit::TyContext};
use rustc_session::config::EntryFnType;
@ -689,7 +690,8 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirNeighborCollector<'a, 'tcx> {
mir::CastKind::Pointer(PointerCast::Unsize),
ref operand,
target_ty,
) => {
)
| mir::Rvalue::Cast(mir::CastKind::DynStar, ref operand, target_ty) => {
let target_ty = self.monomorphize(target_ty);
let source_ty = operand.ty(self.body, self.tcx);
let source_ty = self.monomorphize(source_ty);
@ -698,7 +700,7 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirNeighborCollector<'a, 'tcx> {
// This could also be a different Unsize instruction, like
// from a fixed sized array to a slice. But we are only
// interested in things that produce a vtable.
if target_ty.is_trait() && !source_ty.is_trait() {
if (target_ty.is_trait() || target_ty.is_dyn_star()) && !source_ty.is_trait() {
create_mono_items_for_vtable_methods(
self.tcx,
target_ty,
@ -1112,6 +1114,11 @@ fn find_vtable_types_for_unsizing<'tcx>(
ptr_vtable(source_ty.boxed_ty(), target_ty.boxed_ty())
}
// T as dyn* Trait
(_, &ty::Dynamic(_, _, TraitObjectRepresentation::Sized)) => {
ptr_vtable(source_ty, target_ty)
}
(&ty::Adt(source_adt_def, source_substs), &ty::Adt(target_adt_def, target_substs)) => {
assert_eq!(source_adt_def, target_adt_def);

2
src/test/ui/dyn-star/make-dyn-star.rs
View File

@ -4,7 +4,7 @@
use std::fmt::Debug;
fn make_dyn_star(i: usize) {
let dyn_i: dyn* Debug = i as dyn* Debug;
let _dyn_i: dyn* Debug = i as dyn* Debug;
}
fn main() {