2013-01-10 12:59:58 -06:00
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// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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/*!
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# Moves Computation
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The goal of this file is to compute which
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expressions/patterns/captures correspond to *moves*. This is
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generally a function of the context in which the expression appears as
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well as the expression's type.
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## Examples
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We will use the following fragment of code to explain the various
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considerations. Note that in this code `x` is used after it has been
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moved here. This is not relevant to this pass, though the information
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we compute would later be used to detect this error (see the section
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Enforcement of Moves, below).
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struct Foo { a: int, b: ~int }
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let x: Foo = ...;
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let w = (x {Read}).a; // Read
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let y = (x {Move}).b; // Move
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let z = copy (x {Read}).b; // Read
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Let's look at these examples one by one. In the first case, `w`, the
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expression being assigned is `x.a`, which has `int` type. In that
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case, the value is read, and the container (`x`) is also read.
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In the second case, `y`, `x.b` is being assigned which has type
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`~int`. Because this type moves by default, that will be a move
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reference. Whenever we move from a compound expression like `x.b` (or
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`x[b]` or `*x` or `{x)[b].c`, etc), this invalidates all containing
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expressions since we do not currently permit "incomplete" variables
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where part of them has been moved and part has not. In this case,
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this means that the reference to `x` is also a move. We'll see later,
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though, that these kind of "partial moves", where part of the
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expression has been moved, are classified and stored somewhat
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differently.
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The final example (`z`) is `copy x.b`: in this case, although the
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expression being assigned has type `~int`, there are no moves
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involved.
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### Patterns
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For each binding in a match or let pattern, we also compute a read
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or move designation. A move binding means that the value will be
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moved from the value being matched. As a result, the expression
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being matched (aka, the 'discriminant') is either moved or read
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depending on whethe the bindings move the value they bind to out of
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the discriminant.
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For examples, consider this match expression:
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match x {Move} {
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Foo { a: a {Read}, b: b {Move} } => {...}
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}
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Here, the binding `b` is value (not ref) mode, and `b` has type
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`~int`, and therefore the discriminant expression `x` would be
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incomplete so it also considered moved.
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In the following two examples, in contrast, the mode of `b` is either
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`copy` or `ref` and hence the overall result is a read:
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match x {Read} {
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Foo { a: a {Read}, b: copy b {Read} } => {...}
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}
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match x {Read} {
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Foo { a: a {Read}, b: ref b {Read} } => {...}
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}
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Similar reasoning can be applied to `let` expressions:
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let Foo { a: a {Read}, b: b {Move} } = x {Move};
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let Foo { a: a {Read}, b: copy b {Read} } = x {Read};
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let Foo { a: a {Read}, b: ref b {Read} } = x {Read};
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## Output
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2013-05-22 05:54:35 -05:00
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The pass results in the struct `MoveMaps` which contains several
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maps:
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`moves_map` is a set containing the id of every *outermost expression* or
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*binding* that causes a move. Note that `moves_map` only contains the *outermost
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expressions* that are moved. Therefore, if you have a use of `x.b`,
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as in the example `y` above, the expression `x.b` would be in the
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`moves_map` but not `x`. The reason for this is that, for most
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purposes, it's only the outermost expression that is needed. The
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borrow checker and trans, for example, only care about the outermost
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expressions that are moved. It is more efficient therefore just to
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store those entries.
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Sometimes though we want to know the variables that are moved (in
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particular in the borrow checker). For these cases, the set
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`moved_variables_set` just collects the ids of variables that are
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moved.
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Finally, the `capture_map` maps from the node_id of a closure
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expression to an array of `CaptureVar` structs detailing which
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variables are captured and how (by ref, by copy, by move).
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## Enforcement of Moves
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2013-05-28 08:33:31 -05:00
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The enforcement of moves is done by the borrow checker. Please see
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the section "Moves and initialization" in `middle/borrowck/doc.rs`.
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## Distributive property
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Copies are "distributive" over parenthesization, but blocks are
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considered rvalues. What this means is that, for example, neither
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`a.clone()` nor `(a).clone()` will move `a` (presuming that `a` has a
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linear type and `clone()` takes its self by reference), but
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`{a}.clone()` will move `a`, as would `(if cond {a} else {b}).clone()`
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and so on.
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*/
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2013-05-17 17:28:44 -05:00
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2013-01-10 12:59:58 -06:00
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use middle::pat_util::{pat_bindings};
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use middle::freevars;
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use middle::ty;
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use middle::typeck::{method_map};
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use util::ppaux;
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use util::ppaux::Repr;
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use util::common::indenter;
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2013-06-28 17:32:26 -05:00
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use std::at_vec;
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use std::hashmap::{HashSet, HashMap};
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use syntax::ast::*;
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use syntax::ast_util;
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use syntax::visit;
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use syntax::visit::vt;
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use syntax::codemap::span;
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2013-05-15 17:55:57 -05:00
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#[deriving(Encodable, Decodable)]
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pub enum CaptureMode {
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CapCopy, // Copy the value into the closure.
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CapMove, // Move the value into the closure.
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CapRef, // Reference directly from parent stack frame (used by `&fn()`).
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}
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2013-05-15 17:55:57 -05:00
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#[deriving(Encodable, Decodable)]
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pub struct CaptureVar {
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def: def, // Variable being accessed free
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span: span, // Location of an access to this variable
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mode: CaptureMode // How variable is being accessed
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}
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2013-04-03 08:28:36 -05:00
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pub type CaptureMap = @mut HashMap<node_id, @[CaptureVar]>;
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pub type MovesMap = @mut HashSet<node_id>;
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2013-03-15 14:24:24 -05:00
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/**
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* Set of variable node-ids that are moved.
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*
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* Note: The `VariableMovesMap` stores expression ids that
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* are moves, whereas this set stores the ids of the variables
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* that are moved at some point */
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pub type MovedVariablesSet = @mut HashSet<node_id>;
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/** See the section Output on the module comment for explanation. */
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#[deriving(Clone)]
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pub struct MoveMaps {
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moves_map: MovesMap,
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moved_variables_set: MovedVariablesSet,
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capture_map: CaptureMap
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}
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2013-07-02 14:47:32 -05:00
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#[deriving(Clone)]
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struct VisitContext {
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tcx: ty::ctxt,
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method_map: method_map,
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move_maps: MoveMaps
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}
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#[deriving(Eq)]
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enum UseMode {
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Move, // This value or something owned by it is moved.
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Read // Read no matter what the type.
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}
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pub fn compute_moves(tcx: ty::ctxt,
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method_map: method_map,
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crate: &crate) -> MoveMaps
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{
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let visitor = visit::mk_vt(@visit::Visitor {
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visit_fn: compute_modes_for_fn,
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visit_expr: compute_modes_for_expr,
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visit_local: compute_modes_for_local,
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.. *visit::default_visitor()
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});
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let visit_cx = VisitContext {
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tcx: tcx,
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method_map: method_map,
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move_maps: MoveMaps {
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moves_map: @mut HashSet::new(),
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capture_map: @mut HashMap::new(),
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moved_variables_set: @mut HashSet::new()
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}
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};
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visit::visit_crate(crate, (visit_cx, visitor));
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return visit_cx.move_maps;
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}
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2013-03-15 14:24:24 -05:00
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pub fn moved_variable_node_id_from_def(def: def) -> Option<node_id> {
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match def {
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def_binding(nid, _) |
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def_arg(nid, _) |
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def_local(nid, _) |
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def_self(nid, _) => Some(nid),
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_ => None
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}
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}
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2013-06-20 14:25:52 -05:00
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///////////////////////////////////////////////////////////////////////////
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// Expressions
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fn compute_modes_for_local<'a>(local: @local,
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(cx, v): (VisitContext,
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vt<VisitContext>)) {
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cx.use_pat(local.node.pat);
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for local.node.init.iter().advance |&init| {
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cx.use_expr(init, Read, v);
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}
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}
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fn compute_modes_for_fn(fk: &visit::fn_kind,
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decl: &fn_decl,
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body: &blk,
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span: span,
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id: node_id,
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(cx, v): (VisitContext,
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vt<VisitContext>)) {
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for decl.inputs.iter().advance |a| {
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cx.use_pat(a.pat);
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}
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visit::visit_fn(fk, decl, body, span, id, (cx, v));
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}
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fn compute_modes_for_expr(expr: @expr,
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(cx, v): (VisitContext,
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vt<VisitContext>))
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{
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cx.consume_expr(expr, v);
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}
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2013-05-31 17:17:22 -05:00
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impl VisitContext {
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pub fn consume_exprs(&self, exprs: &[@expr], visitor: vt<VisitContext>) {
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for exprs.iter().advance |expr| {
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self.consume_expr(*expr, visitor);
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}
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}
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pub fn consume_expr(&self, expr: @expr, visitor: vt<VisitContext>) {
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/*!
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* Indicates that the value of `expr` will be consumed,
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* meaning either copied or moved depending on its type.
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*/
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2013-05-22 05:54:35 -05:00
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debug!("consume_expr(expr=%s)",
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expr.repr(self.tcx));
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let expr_ty = ty::expr_ty_adjusted(self.tcx, expr);
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if ty::type_moves_by_default(self.tcx, expr_ty) {
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self.move_maps.moves_map.insert(expr.id);
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self.use_expr(expr, Move, visitor);
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} else {
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self.use_expr(expr, Read, visitor);
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};
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}
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pub fn consume_block(&self, blk: &blk, visitor: vt<VisitContext>) {
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/*!
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* Indicates that the value of `blk` will be consumed,
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* meaning either copied or moved depending on its type.
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*/
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2013-07-16 13:08:35 -05:00
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debug!("consume_block(blk.id=%?)", blk.id);
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for blk.stmts.iter().advance |stmt| {
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(visitor.visit_stmt)(*stmt, (*self, visitor));
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}
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for blk.expr.iter().advance |tail_expr| {
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self.consume_expr(*tail_expr, visitor);
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}
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}
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2013-05-31 17:17:22 -05:00
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pub fn use_expr(&self,
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expr: @expr,
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expr_mode: UseMode,
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visitor: vt<VisitContext>) {
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/*!
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* Indicates that `expr` is used with a given mode. This will
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* in turn trigger calls to the subcomponents of `expr`.
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*/
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2013-05-22 05:54:35 -05:00
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debug!("use_expr(expr=%s, mode=%?)",
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expr.repr(self.tcx),
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expr_mode);
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|
|
|
|
|
|
// `expr_mode` refers to the post-adjustment value. If one of
|
|
|
|
// those adjustments is to take a reference, then it's only
|
|
|
|
// reading the underlying expression, not moving it.
|
2013-02-05 21:41:45 -06:00
|
|
|
let comp_mode = match self.tcx.adjustments.find(&expr.id) {
|
2013-03-22 21:26:41 -05:00
|
|
|
Some(&@ty::AutoDerefRef(
|
2013-02-27 18:28:37 -06:00
|
|
|
ty::AutoDerefRef {
|
|
|
|
autoref: Some(_), _})) => Read,
|
2013-05-22 05:54:35 -05:00
|
|
|
_ => expr_mode
|
2013-01-10 12:59:58 -06:00
|
|
|
};
|
|
|
|
|
|
|
|
debug!("comp_mode = %?", comp_mode);
|
|
|
|
|
|
|
|
match expr.node {
|
2013-05-10 17:15:06 -05:00
|
|
|
expr_path(*) | expr_self => {
|
2013-01-10 12:59:58 -06:00
|
|
|
match comp_mode {
|
2013-05-22 05:54:35 -05:00
|
|
|
Move => {
|
2013-05-05 11:17:59 -05:00
|
|
|
let def = self.tcx.def_map.get_copy(&expr.id);
|
2013-06-10 16:50:12 -05:00
|
|
|
let r = moved_variable_node_id_from_def(def);
|
|
|
|
for r.iter().advance |&id| {
|
2013-03-15 14:24:24 -05:00
|
|
|
self.move_maps.moved_variables_set.insert(id);
|
|
|
|
}
|
2013-01-10 12:59:58 -06:00
|
|
|
}
|
|
|
|
Read => {}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2013-06-01 17:31:56 -05:00
|
|
|
expr_unary(_, deref, base) => { // *base
|
2013-01-10 12:59:58 -06:00
|
|
|
if !self.use_overloaded_operator(
|
2013-03-26 14:04:30 -05:00
|
|
|
expr, base, [], visitor)
|
2013-01-10 12:59:58 -06:00
|
|
|
{
|
|
|
|
// Moving out of *base moves out of base.
|
|
|
|
self.use_expr(base, comp_mode, visitor);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
expr_field(base, _, _) => { // base.f
|
|
|
|
// Moving out of base.f moves out of base.
|
|
|
|
self.use_expr(base, comp_mode, visitor);
|
|
|
|
}
|
|
|
|
|
2013-06-01 17:31:56 -05:00
|
|
|
expr_index(_, lhs, rhs) => { // lhs[rhs]
|
2013-01-10 12:59:58 -06:00
|
|
|
if !self.use_overloaded_operator(
|
2013-03-26 14:04:30 -05:00
|
|
|
expr, lhs, [rhs], visitor)
|
2013-01-10 12:59:58 -06:00
|
|
|
{
|
|
|
|
self.use_expr(lhs, comp_mode, visitor);
|
|
|
|
self.consume_expr(rhs, visitor);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
expr_call(callee, ref args, _) => { // callee(args)
|
2013-06-17 17:02:17 -05:00
|
|
|
// Figure out whether the called function is consumed.
|
|
|
|
let mode = match ty::get(ty::expr_ty(self.tcx, callee)).sty {
|
|
|
|
ty::ty_closure(ref cty) => {
|
|
|
|
match cty.onceness {
|
|
|
|
Once => Move,
|
|
|
|
Many => Read,
|
|
|
|
}
|
|
|
|
},
|
|
|
|
ty::ty_bare_fn(*) => Read,
|
|
|
|
ref x =>
|
|
|
|
self.tcx.sess.span_bug(callee.span,
|
|
|
|
fmt!("non-function type in moves for expr_call: %?", x)),
|
|
|
|
};
|
|
|
|
// Note we're not using consume_expr, which uses type_moves_by_default
|
|
|
|
// to determine the mode, for this. The reason is that while stack
|
|
|
|
// closures should be noncopyable, they shouldn't move by default;
|
|
|
|
// calling a closure should only consume it if it's once.
|
|
|
|
if mode == Move {
|
|
|
|
self.move_maps.moves_map.insert(callee.id);
|
|
|
|
}
|
|
|
|
self.use_expr(callee, mode, visitor);
|
2013-01-10 12:59:58 -06:00
|
|
|
self.use_fn_args(callee.id, *args, visitor);
|
|
|
|
}
|
|
|
|
|
2013-06-01 17:31:56 -05:00
|
|
|
expr_method_call(callee_id, rcvr, _, _, ref args, _) => { // callee.m(args)
|
2013-01-10 12:59:58 -06:00
|
|
|
// Implicit self is equivalent to & mode, but every
|
|
|
|
// other kind should be + mode.
|
2013-06-01 17:31:56 -05:00
|
|
|
self.use_receiver(rcvr, visitor);
|
|
|
|
self.use_fn_args(callee_id, *args, visitor);
|
2013-01-10 12:59:58 -06:00
|
|
|
}
|
|
|
|
|
|
|
|
expr_struct(_, ref fields, opt_with) => {
|
2013-06-21 07:29:53 -05:00
|
|
|
for fields.iter().advance |field| {
|
2013-01-10 12:59:58 -06:00
|
|
|
self.consume_expr(field.node.expr, visitor);
|
|
|
|
}
|
|
|
|
|
2013-06-10 16:50:12 -05:00
|
|
|
for opt_with.iter().advance |with_expr| {
|
2013-01-31 19:12:29 -06:00
|
|
|
// If there are any fields whose type is move-by-default,
|
|
|
|
// then `with` is consumed, otherwise it is only read
|
|
|
|
let with_ty = ty::expr_ty(self.tcx, *with_expr);
|
|
|
|
let with_fields = match ty::get(with_ty).sty {
|
|
|
|
ty::ty_struct(did, ref substs) => {
|
|
|
|
ty::struct_fields(self.tcx, did, substs)
|
|
|
|
}
|
|
|
|
ref r => {
|
|
|
|
self.tcx.sess.span_bug(
|
|
|
|
with_expr.span,
|
|
|
|
fmt!("bad base expr type in record: %?", r))
|
|
|
|
}
|
|
|
|
};
|
|
|
|
|
|
|
|
// The `with` expr must be consumed if it contains
|
|
|
|
// any fields which (1) were not explicitly
|
|
|
|
// specified and (2) have a type that
|
|
|
|
// moves-by-default:
|
2013-07-04 21:13:26 -05:00
|
|
|
let consume_with = with_fields.iter().any(|tf| {
|
|
|
|
!fields.iter().any(|f| f.node.ident == tf.ident) &&
|
2013-02-07 21:33:12 -06:00
|
|
|
ty::type_moves_by_default(self.tcx, tf.mt.ty)
|
2013-01-31 19:12:29 -06:00
|
|
|
});
|
|
|
|
|
|
|
|
if consume_with {
|
|
|
|
self.consume_expr(*with_expr, visitor);
|
|
|
|
} else {
|
|
|
|
self.use_expr(*with_expr, Read, visitor);
|
|
|
|
}
|
2013-01-10 12:59:58 -06:00
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
expr_tup(ref exprs) => {
|
|
|
|
self.consume_exprs(*exprs, visitor);
|
|
|
|
}
|
|
|
|
|
|
|
|
expr_if(cond_expr, ref then_blk, opt_else_expr) => {
|
|
|
|
self.consume_expr(cond_expr, visitor);
|
|
|
|
self.consume_block(then_blk, visitor);
|
2013-06-10 16:50:12 -05:00
|
|
|
for opt_else_expr.iter().advance |else_expr| {
|
2013-01-10 12:59:58 -06:00
|
|
|
self.consume_expr(*else_expr, visitor);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
expr_match(discr, ref arms) => {
|
|
|
|
// We must do this first so that `arms_have_by_move_bindings`
|
|
|
|
// below knows which bindings are moves.
|
2013-06-21 07:29:53 -05:00
|
|
|
for arms.iter().advance |arm| {
|
2013-01-10 12:59:58 -06:00
|
|
|
self.consume_arm(arm, visitor);
|
|
|
|
}
|
|
|
|
|
2013-05-22 05:54:35 -05:00
|
|
|
// The discriminant may, in fact, be partially moved
|
|
|
|
// if there are by-move bindings, but borrowck deals
|
|
|
|
// with that itself.
|
|
|
|
self.use_expr(discr, Read, visitor);
|
2013-01-10 12:59:58 -06:00
|
|
|
}
|
|
|
|
|
|
|
|
expr_paren(base) => {
|
|
|
|
// Note: base is not considered a *component* here, so
|
|
|
|
// use `expr_mode` not `comp_mode`.
|
|
|
|
self.use_expr(base, expr_mode, visitor);
|
|
|
|
}
|
|
|
|
|
|
|
|
expr_vec(ref exprs, _) => {
|
|
|
|
self.consume_exprs(*exprs, visitor);
|
|
|
|
}
|
|
|
|
|
|
|
|
expr_addr_of(_, base) => { // &base
|
|
|
|
self.use_expr(base, Read, visitor);
|
|
|
|
}
|
|
|
|
|
2013-03-15 20:54:39 -05:00
|
|
|
expr_inline_asm(*) |
|
2013-01-10 12:59:58 -06:00
|
|
|
expr_break(*) |
|
|
|
|
expr_again(*) |
|
2013-03-12 19:53:25 -05:00
|
|
|
expr_lit(*) => {}
|
2013-01-10 12:59:58 -06:00
|
|
|
|
|
|
|
expr_loop(ref blk, _) => {
|
|
|
|
self.consume_block(blk, visitor);
|
|
|
|
}
|
|
|
|
|
2013-03-26 23:42:01 -05:00
|
|
|
expr_log(a_expr, b_expr) => {
|
2013-01-10 12:59:58 -06:00
|
|
|
self.consume_expr(a_expr, visitor);
|
|
|
|
self.use_expr(b_expr, Read, visitor);
|
|
|
|
}
|
|
|
|
|
|
|
|
expr_while(cond_expr, ref blk) => {
|
|
|
|
self.consume_expr(cond_expr, visitor);
|
|
|
|
self.consume_block(blk, visitor);
|
|
|
|
}
|
|
|
|
|
2013-06-01 17:31:56 -05:00
|
|
|
expr_unary(_, _, lhs) => {
|
2013-01-10 12:59:58 -06:00
|
|
|
if !self.use_overloaded_operator(
|
2013-03-26 14:04:30 -05:00
|
|
|
expr, lhs, [], visitor)
|
2013-01-10 12:59:58 -06:00
|
|
|
{
|
|
|
|
self.consume_expr(lhs, visitor);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2013-06-01 17:31:56 -05:00
|
|
|
expr_binary(_, _, lhs, rhs) => {
|
2013-01-10 12:59:58 -06:00
|
|
|
if !self.use_overloaded_operator(
|
2013-03-26 14:04:30 -05:00
|
|
|
expr, lhs, [rhs], visitor)
|
2013-01-10 12:59:58 -06:00
|
|
|
{
|
|
|
|
self.consume_expr(lhs, visitor);
|
|
|
|
self.consume_expr(rhs, visitor);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
expr_block(ref blk) => {
|
|
|
|
self.consume_block(blk, visitor);
|
|
|
|
}
|
|
|
|
|
|
|
|
expr_ret(ref opt_expr) => {
|
2013-06-10 16:50:12 -05:00
|
|
|
for opt_expr.iter().advance |expr| {
|
2013-01-10 12:59:58 -06:00
|
|
|
self.consume_expr(*expr, visitor);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
expr_assign(lhs, rhs) => {
|
|
|
|
self.use_expr(lhs, Read, visitor);
|
|
|
|
self.consume_expr(rhs, visitor);
|
|
|
|
}
|
|
|
|
|
|
|
|
expr_cast(base, _) => {
|
|
|
|
self.consume_expr(base, visitor);
|
|
|
|
}
|
|
|
|
|
2013-06-01 17:31:56 -05:00
|
|
|
expr_assign_op(_, _, lhs, rhs) => {
|
2013-01-10 12:59:58 -06:00
|
|
|
// FIXME(#4712) --- Overloaded operators?
|
|
|
|
//
|
|
|
|
// if !self.use_overloaded_operator(
|
|
|
|
// expr, DoDerefArgs, lhs, [rhs], visitor)
|
|
|
|
// {
|
|
|
|
self.consume_expr(lhs, visitor);
|
|
|
|
self.consume_expr(rhs, visitor);
|
|
|
|
// }
|
|
|
|
}
|
|
|
|
|
|
|
|
expr_repeat(base, count, _) => {
|
|
|
|
self.consume_expr(base, visitor);
|
|
|
|
self.consume_expr(count, visitor);
|
|
|
|
}
|
|
|
|
|
|
|
|
expr_loop_body(base) |
|
|
|
|
expr_do_body(base) => {
|
|
|
|
self.use_expr(base, comp_mode, visitor);
|
|
|
|
}
|
|
|
|
|
2013-06-20 14:25:52 -05:00
|
|
|
expr_fn_block(ref decl, ref body) => {
|
2013-06-24 12:30:35 -05:00
|
|
|
for decl.inputs.iter().advance |a| {
|
2013-06-20 14:25:52 -05:00
|
|
|
self.use_pat(a.pat);
|
|
|
|
}
|
2013-01-10 12:59:58 -06:00
|
|
|
let cap_vars = self.compute_captures(expr.id);
|
|
|
|
self.move_maps.capture_map.insert(expr.id, cap_vars);
|
|
|
|
self.consume_block(body, visitor);
|
|
|
|
}
|
|
|
|
|
|
|
|
expr_vstore(base, _) => {
|
|
|
|
self.use_expr(base, comp_mode, visitor);
|
|
|
|
}
|
|
|
|
|
|
|
|
expr_mac(*) => {
|
|
|
|
self.tcx.sess.span_bug(
|
|
|
|
expr.span,
|
2013-04-30 11:47:52 -05:00
|
|
|
"macro expression remains after expansion");
|
2013-01-10 12:59:58 -06:00
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2013-05-31 17:17:22 -05:00
|
|
|
pub fn use_overloaded_operator(&self,
|
2013-06-27 08:04:22 -05:00
|
|
|
expr: &expr,
|
2013-05-31 17:17:22 -05:00
|
|
|
receiver_expr: @expr,
|
|
|
|
arg_exprs: &[@expr],
|
|
|
|
visitor: vt<VisitContext>)
|
|
|
|
-> bool {
|
2013-02-08 16:08:02 -06:00
|
|
|
if !self.method_map.contains_key(&expr.id) {
|
2013-01-10 12:59:58 -06:00
|
|
|
return false;
|
|
|
|
}
|
|
|
|
|
2013-03-27 04:40:56 -05:00
|
|
|
self.use_receiver(receiver_expr, visitor);
|
2013-01-10 12:59:58 -06:00
|
|
|
|
2013-03-26 14:04:30 -05:00
|
|
|
// for overloaded operatrs, we are always passing in a
|
|
|
|
// borrowed pointer, so it's always read mode:
|
2013-06-21 07:29:53 -05:00
|
|
|
for arg_exprs.iter().advance |arg_expr| {
|
2013-03-26 14:04:30 -05:00
|
|
|
self.use_expr(*arg_expr, Read, visitor);
|
2013-01-10 12:59:58 -06:00
|
|
|
}
|
|
|
|
|
|
|
|
return true;
|
|
|
|
}
|
|
|
|
|
2013-05-31 17:17:22 -05:00
|
|
|
pub fn consume_arm(&self, arm: &arm, visitor: vt<VisitContext>) {
|
2013-06-10 16:50:12 -05:00
|
|
|
for arm.pats.iter().advance |pat| {
|
2013-01-10 12:59:58 -06:00
|
|
|
self.use_pat(*pat);
|
|
|
|
}
|
|
|
|
|
2013-06-10 16:50:12 -05:00
|
|
|
for arm.guard.iter().advance |guard| {
|
2013-01-10 12:59:58 -06:00
|
|
|
self.consume_expr(*guard, visitor);
|
|
|
|
}
|
|
|
|
|
|
|
|
self.consume_block(&arm.body, visitor);
|
|
|
|
}
|
|
|
|
|
2013-05-31 17:17:22 -05:00
|
|
|
pub fn use_pat(&self, pat: @pat) {
|
2013-01-10 12:59:58 -06:00
|
|
|
/*!
|
|
|
|
*
|
|
|
|
* Decides whether each binding in a pattern moves the value
|
|
|
|
* into itself or not based on its type and annotation.
|
|
|
|
*/
|
|
|
|
|
2013-06-20 14:25:52 -05:00
|
|
|
do pat_bindings(self.tcx.def_map, pat) |bm, id, _span, path| {
|
2013-05-22 05:54:35 -05:00
|
|
|
let binding_moves = match bm {
|
|
|
|
bind_by_ref(_) => false,
|
2013-01-10 12:59:58 -06:00
|
|
|
bind_infer => {
|
|
|
|
let pat_ty = ty::node_id_to_type(self.tcx, id);
|
2013-06-20 14:25:52 -05:00
|
|
|
debug!("pattern %? %s type is %s",
|
|
|
|
id,
|
|
|
|
ast_util::path_to_ident(path).repr(self.tcx),
|
|
|
|
pat_ty.repr(self.tcx));
|
2013-05-22 05:54:35 -05:00
|
|
|
ty::type_moves_by_default(self.tcx, pat_ty)
|
2013-01-10 12:59:58 -06:00
|
|
|
}
|
|
|
|
};
|
|
|
|
|
2013-05-29 18:59:33 -05:00
|
|
|
debug!("pattern binding %?: bm=%?, binding_moves=%b",
|
|
|
|
id, bm, binding_moves);
|
|
|
|
|
2013-05-22 05:54:35 -05:00
|
|
|
if binding_moves {
|
|
|
|
self.move_maps.moves_map.insert(id);
|
2013-01-10 12:59:58 -06:00
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}
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}
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}
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|
|
|
2013-05-31 17:17:22 -05:00
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|
|
pub fn use_receiver(&self,
|
|
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|
receiver_expr: @expr,
|
|
|
|
visitor: vt<VisitContext>) {
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2013-04-24 03:29:46 -05:00
|
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|
self.use_fn_arg(receiver_expr, visitor);
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2013-01-10 12:59:58 -06:00
|
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|
}
|
|
|
|
|
2013-05-31 17:17:22 -05:00
|
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|
pub fn use_fn_args(&self,
|
|
|
|
_: node_id,
|
|
|
|
arg_exprs: &[@expr],
|
|
|
|
visitor: vt<VisitContext>) {
|
2013-04-24 03:29:46 -05:00
|
|
|
//! Uses the argument expressions.
|
2013-06-21 07:29:53 -05:00
|
|
|
for arg_exprs.iter().advance |arg_expr| {
|
2013-04-24 03:29:46 -05:00
|
|
|
self.use_fn_arg(*arg_expr, visitor);
|
2013-01-10 12:59:58 -06:00
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2013-05-31 17:17:22 -05:00
|
|
|
pub fn use_fn_arg(&self, arg_expr: @expr, visitor: vt<VisitContext>) {
|
2013-04-24 03:29:46 -05:00
|
|
|
//! Uses the argument.
|
|
|
|
self.consume_expr(arg_expr, visitor)
|
2013-01-10 12:59:58 -06:00
|
|
|
}
|
|
|
|
|
2013-05-31 17:17:22 -05:00
|
|
|
pub fn arms_have_by_move_bindings(&self,
|
|
|
|
moves_map: MovesMap,
|
|
|
|
arms: &[arm])
|
|
|
|
-> Option<@pat> {
|
2013-06-21 07:29:53 -05:00
|
|
|
for arms.iter().advance |arm| {
|
|
|
|
for arm.pats.iter().advance |&pat| {
|
2013-05-22 05:54:35 -05:00
|
|
|
for ast_util::walk_pat(pat) |p| {
|
|
|
|
if moves_map.contains(&p.id) {
|
|
|
|
return Some(p);
|
2013-01-10 12:59:58 -06:00
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
2013-05-22 05:54:35 -05:00
|
|
|
return None;
|
2013-01-10 12:59:58 -06:00
|
|
|
}
|
|
|
|
|
2013-05-31 17:17:22 -05:00
|
|
|
pub fn compute_captures(&self, fn_expr_id: node_id) -> @[CaptureVar] {
|
2013-01-10 12:59:58 -06:00
|
|
|
debug!("compute_capture_vars(fn_expr_id=%?)", fn_expr_id);
|
|
|
|
let _indenter = indenter();
|
|
|
|
|
|
|
|
let fn_ty = ty::node_id_to_type(self.tcx, fn_expr_id);
|
2013-01-31 19:12:29 -06:00
|
|
|
let sigil = ty::ty_closure_sigil(fn_ty);
|
2013-01-10 12:59:58 -06:00
|
|
|
let freevars = freevars::get_freevars(self.tcx, fn_expr_id);
|
2013-01-31 19:12:29 -06:00
|
|
|
if sigil == BorrowedSigil {
|
2013-01-10 12:59:58 -06:00
|
|
|
// &fn() captures everything by ref
|
|
|
|
at_vec::from_fn(freevars.len(), |i| {
|
|
|
|
let fvar = &freevars[i];
|
|
|
|
CaptureVar {def: fvar.def, span: fvar.span, mode: CapRef}
|
|
|
|
})
|
|
|
|
} else {
|
|
|
|
// @fn() and ~fn() capture by copy or by move depending on type
|
|
|
|
at_vec::from_fn(freevars.len(), |i| {
|
|
|
|
let fvar = &freevars[i];
|
|
|
|
let fvar_def_id = ast_util::def_id_of_def(fvar.def).node;
|
|
|
|
let fvar_ty = ty::node_id_to_type(self.tcx, fvar_def_id);
|
|
|
|
debug!("fvar_def_id=%? fvar_ty=%s",
|
|
|
|
fvar_def_id, ppaux::ty_to_str(self.tcx, fvar_ty));
|
2013-02-07 21:33:12 -06:00
|
|
|
let mode = if ty::type_moves_by_default(self.tcx, fvar_ty) {
|
2013-01-10 12:59:58 -06:00
|
|
|
CapMove
|
|
|
|
} else {
|
|
|
|
CapCopy
|
|
|
|
};
|
|
|
|
CaptureVar {def: fvar.def, span: fvar.span, mode:mode}
|
|
|
|
})
|
|
|
|
}
|
|
|
|
}
|
2013-01-31 20:24:09 -06:00
|
|
|
}
|