rustc: Less copy
This commit is contained in:
Tim Chevalier
parent
2d33e308ac
commit
cff4f1476e
1 changed files with 152 additions and 143 deletions
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@ -481,161 +481,170 @@ fn wild() -> @pat {
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@pat {id: 0, node: pat_wild, span: ast_util::dummy_sp()}
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}
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fn specialize(cx: @MatchCheckCtxt, r: ~[@pat], ctor_id: ctor, arity: uint,
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fn specialize(cx: @MatchCheckCtxt, +r: ~[@pat], ctor_id: ctor, arity: uint,
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left_ty: ty::t) -> Option<~[@pat]> {
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let r0 = raw_pat(r[0]);
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match /*bad*/copy r0.node {
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pat_wild => Some(vec::append(vec::from_elem(arity, wild()),
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vec::tail(r))),
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pat_ident(_, _, _) => {
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match cx.tcx.def_map.find(r0.id) {
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Some(def_variant(_, id)) => {
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if variant(id) == ctor_id { Some(vec::tail(r)) }
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else { None }
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}
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Some(def_const(did)) => {
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let const_expr = lookup_const_by_id(cx.tcx, did).get();
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let e_v = eval_const_expr(cx.tcx, const_expr);
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let match_ = match ctor_id {
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val(ref v) => compare_const_vals(e_v, (*v)) == 0,
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range(ref c_lo, ref c_hi) => {
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compare_const_vals((*c_lo), e_v) >= 0 &&
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compare_const_vals((*c_hi), e_v) <= 0
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// Sad, but I can't get rid of this easily
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let mut r0 = copy *raw_pat(r[0]);
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match r0 {
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pat{id: pat_id, node: n, span: pat_span} =>
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match n {
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pat_wild => Some(vec::append(vec::from_elem(arity, wild()),
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vec::tail(r))),
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pat_ident(_, _, _) => {
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match cx.tcx.def_map.find(pat_id) {
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Some(def_variant(_, id)) => {
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if variant(id) == ctor_id { Some(vec::tail(r)) }
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else { None }
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}
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Some(def_const(did)) => {
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let const_expr =
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lookup_const_by_id(cx.tcx, did).get();
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let e_v = eval_const_expr(cx.tcx, const_expr);
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let match_ = match ctor_id {
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val(ref v) => compare_const_vals(e_v, (*v)) == 0,
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range(ref c_lo, ref c_hi) => {
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compare_const_vals((*c_lo), e_v) >= 0 &&
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compare_const_vals((*c_hi), e_v) <= 0
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}
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single => true,
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_ => fail ~"type error"
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};
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if match_ { Some(vec::tail(r)) } else { None }
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}
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_ => Some(vec::append(vec::from_elem(arity, wild()),
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vec::tail(r)))
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}
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single => true,
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_ => fail ~"type error"
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};
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if match_ { Some(vec::tail(r)) } else { None }
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}
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_ => Some(vec::append(vec::from_elem(arity, wild()), vec::tail(r)))
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}
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}
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pat_enum(_, args) => {
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match cx.tcx.def_map.get(r0.id) {
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def_variant(_, id) if variant(id) == ctor_id => {
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let args = match args {
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Some(args) => args,
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None => vec::from_elem(arity, wild())
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};
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Some(vec::append(args, vec::tail(r)))
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}
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def_variant(_, _) => None,
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def_struct(*) => {
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// XXX: Is this right? --pcw
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let new_args;
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match args {
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Some(args) => new_args = args,
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None => new_args = vec::from_elem(arity, wild())
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}
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Some(vec::append(new_args, vec::tail(r)))
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}
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_ => None
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}
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}
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pat_rec(flds, _) => {
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let ty_flds = match /*bad*/copy ty::get(left_ty).sty {
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ty::ty_rec(flds) => flds,
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_ => fail ~"bad type for pat_rec"
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};
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let args = vec::map(ty_flds, |ty_fld| {
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match vec::find(flds, |f| f.ident == ty_fld.ident ) {
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Some(f) => f.pat,
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_ => wild()
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}
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});
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Some(vec::append(args, vec::tail(r)))
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}
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pat_struct(_, flds, _) => {
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// Is this a struct or an enum variant?
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match cx.tcx.def_map.get(r0.id) {
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def_variant(_, variant_id) => {
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if variant(variant_id) == ctor_id {
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// XXX: Is this right? --pcw
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let args = flds.map(|ty_field| {
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match vec::find(flds, |f| f.ident == ty_field.ident) {
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Some(f) => f.pat,
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_ => wild()
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pat_enum(_, args) => {
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match cx.tcx.def_map.get(pat_id) {
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def_variant(_, id) if variant(id) == ctor_id => {
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let args = match args {
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Some(args) => args,
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None => vec::from_elem(arity, wild())
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};
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Some(vec::append(args, vec::tail(r)))
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}
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def_variant(_, _) => None,
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def_struct(*) => {
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// XXX: Is this right? --pcw
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let new_args;
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match args {
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Some(args) => new_args = args,
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None => new_args = vec::from_elem(arity, wild())
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}
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});
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Some(vec::append(args, vec::tail(r)))
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} else {
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None
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Some(vec::append(new_args, vec::tail(r)))
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}
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_ => None
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}
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}
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_ => {
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// Grab the class data that we care about.
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let class_fields, class_id;
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match ty::get(left_ty).sty {
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ty::ty_struct(cid, _) => {
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class_id = cid;
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class_fields = ty::lookup_struct_fields(cx.tcx,
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class_id);
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}
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_ => {
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cx.tcx.sess.span_bug(r0.span, ~"struct pattern \
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didn't resolve to a \
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struct");
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}
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}
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let args = vec::map(class_fields, |class_field| {
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match vec::find(flds, |f| f.ident == class_field.ident ) {
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Some(f) => f.pat,
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_ => wild()
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pat_rec(ref flds, _) => {
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let ty_flds = match /*bad*/copy ty::get(left_ty).sty {
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ty::ty_rec(flds) => flds,
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_ => fail ~"bad type for pat_rec"
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};
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let args = vec::map(ty_flds, |ty_fld| {
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match flds.find(|f| f.ident == ty_fld.ident) {
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Some(f) => f.pat,
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_ => wild()
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}
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});
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Some(vec::append(args, vec::tail(r)))
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}
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}
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}
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pat_tup(args) => Some(vec::append(args, vec::tail(r))),
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pat_box(a) | pat_uniq(a) | pat_region(a) =>
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Some(vec::append(~[a], vec::tail(r))),
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pat_lit(expr) => {
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let e_v = eval_const_expr(cx.tcx, expr);
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let match_ = match ctor_id {
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val(ref v) => compare_const_vals(e_v, (*v)) == 0,
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range(ref c_lo, ref c_hi) => {
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compare_const_vals((*c_lo), e_v) >= 0 &&
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compare_const_vals((*c_hi), e_v) <= 0
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}
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single => true,
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_ => fail ~"type error"
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};
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if match_ { Some(vec::tail(r)) } else { None }
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}
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pat_range(lo, hi) => {
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let (c_lo, c_hi) = match ctor_id {
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val(ref v) => ((/*bad*/copy *v), (/*bad*/copy *v)),
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range(ref lo, ref hi) => ((/*bad*/copy *lo), (/*bad*/copy *hi)),
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single => return Some(vec::tail(r)),
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_ => fail ~"type error"
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};
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let v_lo = eval_const_expr(cx.tcx, lo),
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v_hi = eval_const_expr(cx.tcx, hi);
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let match_ = compare_const_vals(c_lo, v_lo) >= 0 &&
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compare_const_vals(c_hi, v_hi) <= 0;
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if match_ { Some(vec::tail(r)) } else { None }
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}
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pat_vec(elems, tail) => {
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match ctor_id {
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vec(_) => {
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if elems.len() < arity && tail.is_some() {
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// XXX: Bad copy.
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Some(vec::append(
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vec::append(copy elems, vec::from_elem(
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arity - elems.len(), wild()
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)),
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vec::tail(r)
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))
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} else if elems.len() == arity {
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Some(vec::append(elems, vec::tail(r)))
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} else {
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None
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pat_struct(_, ref flds, _) => {
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// Is this a struct or an enum variant?
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match cx.tcx.def_map.get(pat_id) {
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def_variant(_, variant_id) => {
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if variant(variant_id) == ctor_id {
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// XXX: Is this right? --pcw
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let args = flds.map(|ty_field| {
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match flds.find(|f|
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f.ident == ty_field.ident) {
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Some(f) => f.pat,
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_ => wild()
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}
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});
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Some(vec::append(args, vec::tail(r)))
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} else {
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None
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}
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}
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_ => {
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// Grab the class data that we care about.
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let class_fields, class_id;
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match ty::get(left_ty).sty {
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ty::ty_struct(cid, _) => {
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class_id = cid;
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class_fields =
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ty::lookup_struct_fields(cx.tcx,
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class_id);
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}
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_ => {
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cx.tcx.sess.span_bug(pat_span,
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~"struct pattern didn't resolve to a struct");
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}
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}
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let args = vec::map(class_fields, |class_field| {
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match flds.find(|f|
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f.ident == class_field.ident) {
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Some(f) => f.pat,
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_ => wild()
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}
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});
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Some(vec::append(args, vec::tail(r)))
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}
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}
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}
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}
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_ => None
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}
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pat_tup(args) => Some(vec::append(args, vec::tail(r))),
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pat_box(a) | pat_uniq(a) | pat_region(a) =>
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Some(vec::append(~[a], vec::tail(r))),
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pat_lit(expr) => {
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let e_v = eval_const_expr(cx.tcx, expr);
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let match_ = match ctor_id {
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val(ref v) => compare_const_vals(e_v, (*v)) == 0,
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range(ref c_lo, ref c_hi) => {
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compare_const_vals((*c_lo), e_v) >= 0 &&
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compare_const_vals((*c_hi), e_v) <= 0
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}
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single => true,
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_ => fail ~"type error"
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};
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if match_ { Some(vec::tail(r)) } else { None }
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}
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pat_range(lo, hi) => {
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let (c_lo, c_hi) = match ctor_id {
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val(ref v) => ((/*bad*/copy *v), (/*bad*/copy *v)),
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range(ref lo, ref hi) =>
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((/*bad*/copy *lo), (/*bad*/copy *hi)),
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single => return Some(vec::tail(r)),
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_ => fail ~"type error"
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};
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let v_lo = eval_const_expr(cx.tcx, lo),
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v_hi = eval_const_expr(cx.tcx, hi);
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let match_ = compare_const_vals(c_lo, v_lo) >= 0 &&
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compare_const_vals(c_hi, v_hi) <= 0;
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if match_ { Some(vec::tail(r)) } else { None }
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}
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pat_vec(elems, tail) => {
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match ctor_id {
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vec(_) => {
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let num_elements = elems.len();
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if num_elements < arity && tail.is_some() {
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Some(vec::append(
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vec::append(elems, vec::from_elem(
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arity - num_elements, wild()
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)),
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vec::tail(r)
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))
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} else if num_elements == arity {
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Some(vec::append(elems, vec::tail(r)))
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} else {
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None
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}
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}
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_ => None
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}
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}
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}
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}
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}
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