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Properly alias-check bindings in for-each loops

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This commit is contained in:
Marijn Haverbeke 2011-09-13 13:34:08 +02:00
parent 45bdff01b2
commit 38e86d708b
1 changed files with 32 additions and 40 deletions
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72
src/comp/middle/alias.rs
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@ -15,13 +15,11 @@ import std::option::{some, none, is_none};
tag valid { valid; overwritten(span, ast::path); val_taken(span, ast::path); }
tag copied { not_allowed; copied; not_copied; }
type restrict = @{root_var: option::t<node_id>,
node_id: node_id,
type restrict = @{node_id: node_id,
span: span,
local_id: uint,
binding: option::t<node_id>,
root_var: option::t<node_id>,
unsafe_tys: [ty::t],
depends_on: [uint],
mutable ok: valid,
mutable copied: copied};
@ -71,7 +69,7 @@ fn visit_expr(cx: @ctx, ex: @ast::expr, sc: scope, v: vt<scope>) {
let handled = true;
alt ex.node {
ast::expr_call(f, args) {
check_call(*cx, f, args, sc);
check_call(*cx, f, args);
handled = false;
}
ast::expr_alt(input, arms) { check_alt(*cx, input, arms, sc, v); }
@ -160,8 +158,7 @@ fn cant_copy(cx: ctx, r: restrict) -> bool {
} else { ret true; }
}
fn check_call(cx: ctx, f: @ast::expr, args: [@ast::expr], sc: scope) ->
[restrict] {
fn check_call(cx: ctx, f: @ast::expr, args: [@ast::expr]) -> [restrict] {
let fty = ty::type_autoderef(cx.tcx, ty::expr_ty(cx.tcx, f));
let arg_ts = ty::ty_fn_args(cx.tcx, fty);
let mut_roots: [{arg: uint, node: node_id}] = [];
@ -180,13 +177,11 @@ fn check_call(cx: ctx, f: @ast::expr, args: [@ast::expr], sc: scope) ->
}
}
let root_var = path_def_id(cx, root.ex);
restricts += [@{root_var: root_var,
node_id: arg.id,
restricts += [@{node_id: arg.id,
span: arg.span,
local_id: cx.next_local,
binding: none::<node_id>,
root_var: root_var,
unsafe_tys: inner_mut(root.ds),
depends_on: deps(sc, root_var),
mutable ok: valid,
mutable copied: alt arg_t.mode {
ast::by_move. { copied }
@ -284,13 +279,11 @@ fn check_alt(cx: ctx, input: @ast::expr, arms: [ast::arm], sc: scope,
}
}
for info in binding_info {
new_sc += [@{root_var: root_var,
node_id: info.id,
new_sc += [@{node_id: info.id,
span: info.span,
local_id: cx.next_local,
binding: some(info.id),
root_var: root_var,
unsafe_tys: info.unsafe,
depends_on: deps(sc, root_var),
mutable ok: valid,
mutable copied: not_copied}];
}
@ -304,9 +297,18 @@ fn check_for_each(cx: ctx, local: @ast::local, call: @ast::expr,
v.visit_expr(call, sc, v);
alt call.node {
ast::expr_call(f, args) {
let restricts = check_call(cx, f, args, sc);
let new_sc = *sc + check_call(cx, f, args);
for proot in *pattern_roots(cx.tcx, [], local.node.pat) {
new_sc += [@{node_id: proot.id,
span: proot.span,
local_id: cx.next_local,
root_var: none::<node_id>,
unsafe_tys: inner_mut(proot.ds),
mutable ok: valid,
mutable copied: not_copied}];
}
register_locals(cx, local.node.pat);
visit::visit_block(blk, @(*sc + restricts), v);
visit::visit_block(blk, @new_sc, v);
}
}
}
@ -330,13 +332,11 @@ fn check_for(cx: ctx, local: @ast::local, seq: @ast::expr, blk: ast::blk,
let root_var = path_def_id(cx, root.ex);
let new_sc = *sc;
for proot in *pattern_roots(cx.tcx, ext_ds, local.node.pat) {
new_sc += [@{root_var: root_var,
node_id: proot.id,
new_sc += [@{node_id: proot.id,
span: proot.span,
local_id: cx.next_local,
binding: some(proot.id),
root_var: root_var,
unsafe_tys: inner_mut(proot.ds),
depends_on: deps(sc, root_var),
mutable ok: valid,
mutable copied: not_copied}];
}
@ -360,7 +360,7 @@ fn check_var(cx: ctx, ex: @ast::expr, p: ast::path, id: ast::node_id,
r.ok = val_taken(ex.span, p);
}
}
} else if r.binding == some(my_defnum) {
} else if r.node_id == my_defnum {
test_scope(cx, sc, r, p);
}
}
@ -387,9 +387,16 @@ fn check_assign(cx: @ctx, dest: @ast::expr, src: @ast::expr, sc: scope,
fn test_scope(cx: ctx, sc: scope, r: restrict, p: ast::path) {
let prob = r.ok;
for dep: uint in r.depends_on {
if prob != valid { break; }
prob = sc[dep].ok;
alt r.root_var {
some(dn) {
for other in *sc {
if other.node_id == dn {
prob = other.ok;
if prob != valid { break; }
}
}
}
_ {}
}
if prob != valid && cant_copy(cx, r) {
let msg =
@ -409,21 +416,6 @@ fn test_scope(cx: ctx, sc: scope, r: restrict, p: ast::path) {
}
}
fn deps(sc: scope, root: option::t<node_id>) -> [uint] {
let result = [];
alt root {
some(dn) {
let i = 0u;
for r: restrict in *sc {
if r.binding == some(dn) { result += [i]; }
i += 1u;
}
}
_ { }
}
ret result;
}
fn path_def(cx: ctx, ex: @ast::expr) -> option::t<ast::def> {
ret alt ex.node {
ast::expr_path(_) { some(cx.tcx.def_map.get(ex.id)) }