bjoernager/rust
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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(