Skip to content

Reimplement type_needs_drop on top of TypeContents #5126

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Closed
wants to merge 1 commit into from
Closed

Reimplement type_needs_drop on top of TypeContents #5126

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
98 changes: 17 additions & 81 deletions src/librustc/middle/ty.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -259,7 +259,6 @@ struct ctxt_ {
rcache: creader_cache,
ccache: constness_cache,
short_names_cache: HashMap<t, @~str>,
needs_drop_cache: HashMap<t, bool>,
needs_unwind_cleanup_cache: HashMap<t, bool>,
tc_cache: @mut LinearMap<uint, TypeContents>,
ast_ty_to_ty_cache: HashMap<node_id, ast_ty_to_ty_cache_entry>,
Expand Down Expand Up @@ -822,7 +821,6 @@ pub fn mk_ctxt(s: session::Session,
rcache: mk_rcache(),
ccache: HashMap(),
short_names_cache: new_ty_hash(),
needs_drop_cache: new_ty_hash(),
needs_unwind_cleanup_cache: new_ty_hash(),
tc_cache: @mut LinearMap::new(),
ast_ty_to_ty_cache: HashMap(),
Expand Down Expand Up @@ -1600,79 +1598,7 @@ pub fn type_is_immediate(ty: t) -> bool {
}

pub fn type_needs_drop(cx: ctxt, ty: t) -> bool {
match cx.needs_drop_cache.find(&ty) {
Some(result) => return result,
None => {/* fall through */ }
}

let mut accum = false;
let result = match /*bad*/copy get(ty).sty {
// scalar types
ty_nil | ty_bot | ty_bool | ty_int(_) | ty_float(_) | ty_uint(_) |
ty_type | ty_ptr(_) | ty_rptr(_, _) |
ty_estr(vstore_fixed(_)) |
ty_estr(vstore_slice(_)) |
ty_evec(_, vstore_slice(_)) |
ty_self => false,

ty_box(_) | ty_uniq(_) |
ty_opaque_box | ty_opaque_closure_ptr(*) |
ty_estr(vstore_uniq) |
ty_estr(vstore_box) |
ty_evec(_, vstore_uniq) |
ty_evec(_, vstore_box) => true,

ty_trait(_, _, vstore_box) |
ty_trait(_, _, vstore_uniq) => true,
ty_trait(_, _, vstore_fixed(_)) |
ty_trait(_, _, vstore_slice(_)) => false,

ty_param(*) | ty_infer(*) | ty_err => true,

ty_evec(mt, vstore_fixed(_)) => type_needs_drop(cx, mt.ty),
ty_unboxed_vec(mt) => type_needs_drop(cx, mt.ty),
ty_rec(flds) => {
for flds.each |f| {
if type_needs_drop(cx, f.mt.ty) { accum = true; }
}
accum
}
ty_struct(did, ref substs) => {
// Any struct with a dtor needs a drop
ty_dtor(cx, did).is_present() || {
for vec::each(ty::struct_fields(cx, did, substs)) |f| {
if type_needs_drop(cx, f.mt.ty) { accum = true; }
}
accum
}
}
ty_tup(elts) => {
for elts.each |m| { if type_needs_drop(cx, *m) { accum = true; } }
accum
}
ty_enum(did, ref substs) => {
let variants = enum_variants(cx, did);
for vec::each(*variants) |variant| {
for variant.args.each |aty| {
// Perform any type parameter substitutions.
let arg_ty = subst(cx, substs, *aty);
if type_needs_drop(cx, arg_ty) { accum = true; }
}
if accum { break; }
}
accum
}
ty_bare_fn(*) => false,
ty_closure(ref fty) => {
match fty.sigil {
ast::BorrowedSigil => false,
ast::ManagedSigil | ast::OwnedSigil => true,
}
}
};

cx.needs_drop_cache.insert(ty, result);
return result;
type_contents(cx, ty).needs_drop(cx)
}

// Some things don't need cleanups during unwinding because the
Expand Down Expand Up @@ -1819,7 +1745,7 @@ pub impl TypeContents {

static fn nonimplicitly_copyable(cx: ctxt) -> TypeContents {
let base = TypeContents::noncopyable(cx) + TC_OWNED_POINTER;
if cx.vecs_implicitly_copyable {base} else {base + TC_OWNED_SLICE}
if cx.vecs_implicitly_copyable {base} else {base + TC_OWNED_VEC}
}

fn is_safe_for_default_mode(&self, cx: ctxt) -> bool {
Expand All @@ -1828,7 +1754,17 @@ pub impl TypeContents {

static fn nondefault_mode(cx: ctxt) -> TypeContents {
let tc = TypeContents::nonimplicitly_copyable(cx);
tc + TC_BIG + TC_OWNED_SLICE // disregard cx.vecs_implicitly_copyable
tc + TC_BIG + TC_OWNED_VEC // disregard cx.vecs_implicitly_copyable
}

fn needs_drop(&self, cx: ctxt) -> bool {
let tc = TC_MANAGED + TC_DTOR + TypeContents::owned(cx);
self.intersects(tc)
}

static fn owned(&self, _cx: ctxt) -> TypeContents {
//! Any kind of owned contents.
TC_OWNED_CLOSURE + TC_OWNED_POINTER + TC_OWNED_VEC
}
}

Expand Down Expand Up @@ -1859,8 +1795,8 @@ const TC_BORROWED_POINTER: TypeContents = TypeContents{bits:0b0000_00000001};
/// Contains an owned pointer (~T) but not slice of some kind
const TC_OWNED_POINTER: TypeContents = TypeContents{bits:0b000000000010};

/// Contains an owned slice
const TC_OWNED_SLICE: TypeContents = TypeContents{bits:0b000000000100};
/// Contains an owned vector ~[] or owned string ~str
const TC_OWNED_VEC: TypeContents = TypeContents{bits:0b000000000100};

/// Contains a ~fn() or a ~Trait, which is non-copyable.
const TC_OWNED_CLOSURE: TypeContents = TypeContents{bits:0b000000001000};
Expand Down Expand Up @@ -1963,7 +1899,7 @@ pub fn type_contents(cx: ctxt, ty: t) -> TypeContents {
}

ty_estr(vstore_uniq) => {
TC_OWNED_SLICE
TC_OWNED_VEC
}

ty_closure(ref c) => {
Expand Down Expand Up @@ -1996,7 +1932,7 @@ pub fn type_contents(cx: ctxt, ty: t) -> TypeContents {
}

ty_evec(mt, vstore_uniq) => {
TC_OWNED_SLICE + tc_mt(cx, mt, cache)
TC_OWNED_VEC + tc_mt(cx, mt, cache)
}

ty_evec(mt, vstore_box) => {
Expand Down