1400 lines
50 KiB
Rust
1400 lines
50 KiB
Rust
// Copyright 2012-2014 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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* # Categorization
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*
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* The job of the categorization module is to analyze an expression to
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* determine what kind of memory is used in evaluating it (for example,
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* where dereferences occur and what kind of pointer is dereferenced;
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* whether the memory is mutable; etc)
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*
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* Categorization effectively transforms all of our expressions into
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* expressions of the following forms (the actual enum has many more
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* possibilities, naturally, but they are all variants of these base
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* forms):
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*
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* E = rvalue // some computed rvalue
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* | x // address of a local variable or argument
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* | *E // deref of a ptr
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* | E.comp // access to an interior component
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*
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* Imagine a routine ToAddr(Expr) that evaluates an expression and returns an
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* address where the result is to be found. If Expr is an lvalue, then this
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* is the address of the lvalue. If Expr is an rvalue, this is the address of
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* some temporary spot in memory where the result is stored.
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*
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* Now, cat_expr() classifies the expression Expr and the address A=ToAddr(Expr)
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* as follows:
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*
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* - cat: what kind of expression was this? This is a subset of the
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* full expression forms which only includes those that we care about
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* for the purpose of the analysis.
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* - mutbl: mutability of the address A
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* - ty: the type of data found at the address A
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*
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* The resulting categorization tree differs somewhat from the expressions
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* themselves. For example, auto-derefs are explicit. Also, an index a[b] is
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* decomposed into two operations: a dereference to reach the array data and
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* then an index to jump forward to the relevant item.
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*
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* ## By-reference upvars
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*
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* One part of the translation which may be non-obvious is that we translate
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* closure upvars into the dereference of a borrowed pointer; this more closely
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* resembles the runtime translation. So, for example, if we had:
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*
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* let mut x = 3;
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* let y = 5;
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* let inc = || x += y;
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*
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* Then when we categorize `x` (*within* the closure) we would yield a
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* result of `*x'`, effectively, where `x'` is a `cat_upvar` reference
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* tied to `x`. The type of `x'` will be a borrowed pointer.
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*/
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#![allow(non_camel_case_types)]
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use middle::def;
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use middle::freevars;
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use middle::ty;
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use middle::typeck;
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use util::nodemap::{DefIdMap, NodeMap};
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use util::ppaux::{ty_to_string, Repr};
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use syntax::ast::{MutImmutable, MutMutable};
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use syntax::ast;
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use syntax::codemap::Span;
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use syntax::print::pprust;
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use syntax::parse::token;
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use std::cell::RefCell;
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use std::rc::Rc;
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#[deriving(Clone, PartialEq)]
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pub enum categorization {
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cat_rvalue(ty::Region), // temporary val, argument is its scope
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cat_static_item,
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cat_copied_upvar(CopiedUpvar), // upvar copied into proc env
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cat_upvar(ty::UpvarId, ty::UpvarBorrow), // by ref upvar from stack closure
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cat_local(ast::NodeId), // local variable
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cat_arg(ast::NodeId), // formal argument
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cat_deref(cmt, uint, PointerKind), // deref of a ptr
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cat_interior(cmt, InteriorKind), // something interior: field, tuple, etc
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cat_downcast(cmt), // selects a particular enum variant (*1)
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cat_discr(cmt, ast::NodeId), // match discriminant (see preserve())
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// (*1) downcast is only required if the enum has more than one variant
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}
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#[deriving(Clone, PartialEq)]
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pub struct CopiedUpvar {
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pub upvar_id: ast::NodeId,
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pub onceness: ast::Onceness,
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pub capturing_proc: ast::NodeId,
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}
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// different kinds of pointers:
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#[deriving(Clone, PartialEq, Eq, Hash)]
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pub enum PointerKind {
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OwnedPtr,
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GcPtr,
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BorrowedPtr(ty::BorrowKind, ty::Region),
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Implicit(ty::BorrowKind, ty::Region), // Implicit deref of a borrowed ptr.
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UnsafePtr(ast::Mutability)
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}
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// We use the term "interior" to mean "something reachable from the
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// base without a pointer dereference", e.g. a field
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#[deriving(Clone, PartialEq, Eq, Hash)]
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pub enum InteriorKind {
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InteriorField(FieldName),
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InteriorElement(ElementKind),
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}
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#[deriving(Clone, PartialEq, Eq, Hash)]
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pub enum FieldName {
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NamedField(ast::Name),
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PositionalField(uint)
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}
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#[deriving(Clone, PartialEq, Eq, Hash)]
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pub enum ElementKind {
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VecElement,
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OtherElement,
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}
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#[deriving(Clone, PartialEq, Eq, Hash, Show)]
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pub enum MutabilityCategory {
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McImmutable, // Immutable.
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McDeclared, // Directly declared as mutable.
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McInherited, // Inherited from the fact that owner is mutable.
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}
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// `cmt`: "Category, Mutability, and Type".
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//
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// a complete categorization of a value indicating where it originated
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// and how it is located, as well as the mutability of the memory in
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// which the value is stored.
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//
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// *WARNING* The field `cmt.type` is NOT necessarily the same as the
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// result of `node_id_to_type(cmt.id)`. This is because the `id` is
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// always the `id` of the node producing the type; in an expression
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// like `*x`, the type of this deref node is the deref'd type (`T`),
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// but in a pattern like `@x`, the `@x` pattern is again a
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// dereference, but its type is the type *before* the dereference
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// (`@T`). So use `cmt.type` to find the type of the value in a consistent
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// fashion. For more details, see the method `cat_pattern`
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#[deriving(Clone, PartialEq)]
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pub struct cmt_ {
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pub id: ast::NodeId, // id of expr/pat producing this value
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pub span: Span, // span of same expr/pat
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pub cat: categorization, // categorization of expr
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pub mutbl: MutabilityCategory, // mutability of expr as lvalue
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pub ty: ty::t // type of the expr (*see WARNING above*)
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}
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pub type cmt = Rc<cmt_>;
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// We pun on *T to mean both actual deref of a ptr as well
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// as accessing of components:
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pub enum deref_kind {
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deref_ptr(PointerKind),
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deref_interior(InteriorKind),
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}
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// Categorizes a derefable type. Note that we include vectors and strings as
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// derefable (we model an index as the combination of a deref and then a
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// pointer adjustment).
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pub fn opt_deref_kind(t: ty::t) -> Option<deref_kind> {
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match ty::get(t).sty {
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ty::ty_uniq(_) |
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ty::ty_closure(box ty::ClosureTy {store: ty::UniqTraitStore, ..}) => {
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Some(deref_ptr(OwnedPtr))
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}
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ty::ty_rptr(r, mt) => {
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let kind = ty::BorrowKind::from_mutbl(mt.mutbl);
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Some(deref_ptr(BorrowedPtr(kind, r)))
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}
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ty::ty_closure(box ty::ClosureTy {
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store: ty::RegionTraitStore(r, _),
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..
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}) => {
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Some(deref_ptr(BorrowedPtr(ty::ImmBorrow, r)))
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}
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ty::ty_box(..) => {
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Some(deref_ptr(GcPtr))
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}
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ty::ty_ptr(ref mt) => {
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Some(deref_ptr(UnsafePtr(mt.mutbl)))
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}
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ty::ty_enum(..) |
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ty::ty_struct(..) => { // newtype
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Some(deref_interior(InteriorField(PositionalField(0))))
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}
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ty::ty_vec(_, _) | ty::ty_str => {
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Some(deref_interior(InteriorElement(element_kind(t))))
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}
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_ => None
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}
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}
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pub fn deref_kind(tcx: &ty::ctxt, t: ty::t) -> deref_kind {
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debug!("deref_kind {}", ty_to_string(tcx, t));
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match opt_deref_kind(t) {
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Some(k) => k,
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None => {
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tcx.sess.bug(
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format!("deref_kind() invoked on non-derefable type {}",
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ty_to_string(tcx, t)).as_slice());
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}
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}
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}
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trait ast_node {
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fn id(&self) -> ast::NodeId;
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fn span(&self) -> Span;
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}
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impl ast_node for ast::Expr {
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fn id(&self) -> ast::NodeId { self.id }
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fn span(&self) -> Span { self.span }
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}
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impl ast_node for ast::Pat {
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fn id(&self) -> ast::NodeId { self.id }
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fn span(&self) -> Span { self.span }
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}
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pub struct MemCategorizationContext<'t,TYPER:'t> {
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typer: &'t TYPER
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}
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pub type McResult<T> = Result<T, ()>;
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/**
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* The `Typer` trait provides the interface for the mem-categorization
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* module to the results of the type check. It can be used to query
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* the type assigned to an expression node, to inquire after adjustments,
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* and so on.
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*
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* This interface is needed because mem-categorization is used from
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* two places: `regionck` and `borrowck`. `regionck` executes before
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* type inference is complete, and hence derives types and so on from
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* intermediate tables. This also implies that type errors can occur,
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* and hence `node_ty()` and friends return a `Result` type -- any
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* error will propagate back up through the mem-categorization
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* routines.
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*
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* In the borrow checker, in contrast, type checking is complete and we
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* know that no errors have occurred, so we simply consult the tcx and we
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* can be sure that only `Ok` results will occur.
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*/
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pub trait Typer {
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fn tcx<'a>(&'a self) -> &'a ty::ctxt;
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fn node_ty(&self, id: ast::NodeId) -> McResult<ty::t>;
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fn node_method_ty(&self, method_call: typeck::MethodCall) -> Option<ty::t>;
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fn adjustments<'a>(&'a self) -> &'a RefCell<NodeMap<ty::AutoAdjustment>>;
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fn is_method_call(&self, id: ast::NodeId) -> bool;
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fn temporary_scope(&self, rvalue_id: ast::NodeId) -> Option<ast::NodeId>;
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fn upvar_borrow(&self, upvar_id: ty::UpvarId) -> ty::UpvarBorrow;
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fn capture_mode(&self, closure_expr_id: ast::NodeId)
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-> freevars::CaptureMode;
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fn unboxed_closures<'a>(&'a self)
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-> &'a RefCell<DefIdMap<ty::UnboxedClosure>>;
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}
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impl MutabilityCategory {
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pub fn from_mutbl(m: ast::Mutability) -> MutabilityCategory {
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match m {
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MutImmutable => McImmutable,
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MutMutable => McDeclared
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}
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}
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pub fn from_borrow_kind(borrow_kind: ty::BorrowKind) -> MutabilityCategory {
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match borrow_kind {
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ty::ImmBorrow => McImmutable,
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ty::UniqueImmBorrow => McImmutable,
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ty::MutBorrow => McDeclared,
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}
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}
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pub fn from_pointer_kind(base_mutbl: MutabilityCategory,
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ptr: PointerKind) -> MutabilityCategory {
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match ptr {
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OwnedPtr => {
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base_mutbl.inherit()
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}
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BorrowedPtr(borrow_kind, _) | Implicit(borrow_kind, _) => {
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MutabilityCategory::from_borrow_kind(borrow_kind)
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}
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GcPtr => {
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McImmutable
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}
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UnsafePtr(m) => {
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MutabilityCategory::from_mutbl(m)
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}
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}
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}
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fn from_def(def: &def::Def) -> MutabilityCategory {
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match *def {
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def::DefFn(..) | def::DefStaticMethod(..) | def::DefSelfTy(..) |
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def::DefMod(..) | def::DefForeignMod(..) | def::DefVariant(..) |
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def::DefTy(..) | def::DefTrait(..) | def::DefPrimTy(..) |
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def::DefTyParam(..) | def::DefUse(..) | def::DefStruct(..) |
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def::DefTyParamBinder(..) | def::DefRegion(..) | def::DefLabel(..) |
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def::DefMethod(..) => fail!("no MutabilityCategory for def: {}", *def),
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def::DefStatic(_, false) => McImmutable,
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def::DefStatic(_, true) => McDeclared,
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def::DefArg(_, binding_mode) |
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def::DefBinding(_, binding_mode) |
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def::DefLocal(_, binding_mode) => match binding_mode {
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ast::BindByValue(ast::MutMutable) => McDeclared,
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_ => McImmutable
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},
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def::DefUpvar(_, def, _, _) => MutabilityCategory::from_def(&*def)
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}
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}
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pub fn inherit(&self) -> MutabilityCategory {
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match *self {
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McImmutable => McImmutable,
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McDeclared => McInherited,
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McInherited => McInherited,
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}
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}
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pub fn is_mutable(&self) -> bool {
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match *self {
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McImmutable => false,
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McInherited => true,
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McDeclared => true,
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}
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}
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pub fn is_immutable(&self) -> bool {
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match *self {
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McImmutable => true,
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McDeclared | McInherited => false
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}
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}
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pub fn to_user_str(&self) -> &'static str {
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match *self {
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McDeclared | McInherited => "mutable",
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McImmutable => "immutable",
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}
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}
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}
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macro_rules! if_ok(
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($inp: expr) => (
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match $inp {
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Ok(v) => { v }
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Err(e) => { return Err(e); }
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}
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)
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)
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impl<'t,TYPER:Typer> MemCategorizationContext<'t,TYPER> {
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pub fn new(typer: &'t TYPER) -> MemCategorizationContext<'t,TYPER> {
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MemCategorizationContext { typer: typer }
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}
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fn tcx(&self) -> &'t ty::ctxt {
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self.typer.tcx()
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}
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fn expr_ty(&self, expr: &ast::Expr) -> McResult<ty::t> {
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self.typer.node_ty(expr.id)
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}
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fn expr_ty_adjusted(&self, expr: &ast::Expr) -> McResult<ty::t> {
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let unadjusted_ty = if_ok!(self.expr_ty(expr));
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Ok(ty::adjust_ty(self.tcx(), expr.span, expr.id, unadjusted_ty,
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self.typer.adjustments().borrow().find(&expr.id),
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|method_call| self.typer.node_method_ty(method_call)))
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}
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fn node_ty(&self, id: ast::NodeId) -> McResult<ty::t> {
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self.typer.node_ty(id)
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}
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fn pat_ty(&self, pat: &ast::Pat) -> McResult<ty::t> {
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self.typer.node_ty(pat.id)
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}
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pub fn cat_expr(&self, expr: &ast::Expr) -> McResult<cmt> {
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match self.typer.adjustments().borrow().find(&expr.id) {
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None => {
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// No adjustments.
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self.cat_expr_unadjusted(expr)
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}
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Some(adjustment) => {
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match *adjustment {
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ty::AutoAddEnv(..) => {
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// Convert a bare fn to a closure by adding NULL env.
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// Result is an rvalue.
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let expr_ty = if_ok!(self.expr_ty_adjusted(expr));
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Ok(self.cat_rvalue_node(expr.id(), expr.span(), expr_ty))
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}
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ty::AutoDerefRef(
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ty::AutoDerefRef {
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autoref: Some(_), ..}) => {
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// Equivalent to &*expr or something similar.
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// Result is an rvalue.
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let expr_ty = if_ok!(self.expr_ty_adjusted(expr));
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Ok(self.cat_rvalue_node(expr.id(), expr.span(), expr_ty))
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}
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ty::AutoDerefRef(
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ty::AutoDerefRef {
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autoref: None, autoderefs: autoderefs}) => {
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// Equivalent to *expr or something similar.
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self.cat_expr_autoderefd(expr, autoderefs)
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}
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}
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}
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}
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}
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pub fn cat_expr_autoderefd(&self,
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expr: &ast::Expr,
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autoderefs: uint)
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-> McResult<cmt> {
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let mut cmt = if_ok!(self.cat_expr_unadjusted(expr));
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for deref in range(1u, autoderefs + 1) {
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cmt = self.cat_deref(expr, cmt, deref, false);
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}
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return Ok(cmt);
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}
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pub fn cat_expr_unadjusted(&self, expr: &ast::Expr) -> McResult<cmt> {
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debug!("cat_expr: id={} expr={}", expr.id, expr.repr(self.tcx()));
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let expr_ty = if_ok!(self.expr_ty(expr));
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match expr.node {
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ast::ExprUnary(ast::UnDeref, ref e_base) => {
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let base_cmt = if_ok!(self.cat_expr(&**e_base));
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Ok(self.cat_deref(expr, base_cmt, 0, false))
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}
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ast::ExprField(ref base, f_name, _) => {
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let base_cmt = if_ok!(self.cat_expr(&**base));
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Ok(self.cat_field(expr, base_cmt, f_name.node, expr_ty))
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}
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ast::ExprIndex(ref base, _) => {
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let method_call = typeck::MethodCall::expr(expr.id());
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match self.typer.node_method_ty(method_call) {
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Some(method_ty) => {
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// If this is an index implemented by a method call, then it will
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// include an implicit deref of the result.
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let ret_ty = ty::ty_fn_ret(method_ty);
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Ok(self.cat_deref(expr,
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self.cat_rvalue_node(expr.id(),
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expr.span(),
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ret_ty), 1, true))
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}
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None => {
|
|
let base_cmt = if_ok!(self.cat_expr(&**base));
|
|
Ok(self.cat_index(expr, base_cmt))
|
|
}
|
|
}
|
|
}
|
|
|
|
ast::ExprPath(_) => {
|
|
let def = self.tcx().def_map.borrow().get_copy(&expr.id);
|
|
self.cat_def(expr.id, expr.span, expr_ty, def)
|
|
}
|
|
|
|
ast::ExprParen(ref e) => {
|
|
self.cat_expr(&**e)
|
|
}
|
|
|
|
ast::ExprAddrOf(..) | ast::ExprCall(..) |
|
|
ast::ExprAssign(..) | ast::ExprAssignOp(..) |
|
|
ast::ExprFnBlock(..) | ast::ExprProc(..) |
|
|
ast::ExprUnboxedFn(..) | ast::ExprRet(..) |
|
|
ast::ExprUnary(..) |
|
|
ast::ExprMethodCall(..) | ast::ExprCast(..) |
|
|
ast::ExprVec(..) | ast::ExprTup(..) | ast::ExprIf(..) |
|
|
ast::ExprBinary(..) | ast::ExprWhile(..) |
|
|
ast::ExprBlock(..) | ast::ExprLoop(..) | ast::ExprMatch(..) |
|
|
ast::ExprLit(..) | ast::ExprBreak(..) | ast::ExprMac(..) |
|
|
ast::ExprAgain(..) | ast::ExprStruct(..) | ast::ExprRepeat(..) |
|
|
ast::ExprInlineAsm(..) | ast::ExprBox(..) |
|
|
ast::ExprForLoop(..) => {
|
|
Ok(self.cat_rvalue_node(expr.id(), expr.span(), expr_ty))
|
|
}
|
|
}
|
|
}
|
|
|
|
pub fn cat_def(&self,
|
|
id: ast::NodeId,
|
|
span: Span,
|
|
expr_ty: ty::t,
|
|
def: def::Def)
|
|
-> McResult<cmt> {
|
|
debug!("cat_def: id={} expr={} def={:?}",
|
|
id, expr_ty.repr(self.tcx()), def);
|
|
|
|
match def {
|
|
def::DefStruct(..) | def::DefVariant(..) | def::DefFn(..) |
|
|
def::DefStaticMethod(..) => {
|
|
Ok(self.cat_rvalue_node(id, span, expr_ty))
|
|
}
|
|
def::DefMod(_) | def::DefForeignMod(_) | def::DefUse(_) |
|
|
def::DefTrait(_) | def::DefTy(_) | def::DefPrimTy(_) |
|
|
def::DefTyParam(..) | def::DefTyParamBinder(..) | def::DefRegion(_) |
|
|
def::DefLabel(_) | def::DefSelfTy(..) | def::DefMethod(..) => {
|
|
Ok(Rc::new(cmt_ {
|
|
id:id,
|
|
span:span,
|
|
cat:cat_static_item,
|
|
mutbl: McImmutable,
|
|
ty:expr_ty
|
|
}))
|
|
}
|
|
|
|
def::DefStatic(_, _) => {
|
|
Ok(Rc::new(cmt_ {
|
|
id:id,
|
|
span:span,
|
|
cat:cat_static_item,
|
|
mutbl: MutabilityCategory::from_def(&def),
|
|
ty:expr_ty
|
|
}))
|
|
}
|
|
|
|
def::DefArg(vid, _) => {
|
|
// Idea: make this could be rewritten to model by-ref
|
|
// stuff as `&const` and `&mut`?
|
|
|
|
Ok(Rc::new(cmt_ {
|
|
id: id,
|
|
span: span,
|
|
cat: cat_arg(vid),
|
|
mutbl: MutabilityCategory::from_def(&def),
|
|
ty:expr_ty
|
|
}))
|
|
}
|
|
|
|
def::DefUpvar(var_id, _, fn_node_id, _) => {
|
|
let ty = if_ok!(self.node_ty(fn_node_id));
|
|
match ty::get(ty).sty {
|
|
ty::ty_closure(ref closure_ty) => {
|
|
// Decide whether to use implicit reference or by copy/move
|
|
// capture for the upvar. This, combined with the onceness,
|
|
// determines whether the closure can move out of it.
|
|
let var_is_refd = match (closure_ty.store, closure_ty.onceness) {
|
|
// Many-shot stack closures can never move out.
|
|
(ty::RegionTraitStore(..), ast::Many) => true,
|
|
// 1-shot stack closures can move out.
|
|
(ty::RegionTraitStore(..), ast::Once) => false,
|
|
// Heap closures always capture by copy/move, and can
|
|
// move out if they are once.
|
|
(ty::UniqTraitStore, _) => false,
|
|
|
|
};
|
|
if var_is_refd {
|
|
self.cat_upvar(id, span, var_id, fn_node_id)
|
|
} else {
|
|
Ok(Rc::new(cmt_ {
|
|
id:id,
|
|
span:span,
|
|
cat:cat_copied_upvar(CopiedUpvar {
|
|
upvar_id: var_id,
|
|
onceness: closure_ty.onceness,
|
|
capturing_proc: fn_node_id,
|
|
}),
|
|
mutbl: MutabilityCategory::from_def(&def),
|
|
ty:expr_ty
|
|
}))
|
|
}
|
|
}
|
|
ty::ty_unboxed_closure(closure_id, _) => {
|
|
let unboxed_closures = self.typer
|
|
.unboxed_closures()
|
|
.borrow();
|
|
let kind = unboxed_closures.get(&closure_id).kind;
|
|
let onceness = match kind {
|
|
ty::FnUnboxedClosureKind |
|
|
ty::FnMutUnboxedClosureKind => ast::Many,
|
|
ty::FnOnceUnboxedClosureKind => ast::Once,
|
|
};
|
|
Ok(Rc::new(cmt_ {
|
|
id: id,
|
|
span: span,
|
|
cat: cat_copied_upvar(CopiedUpvar {
|
|
upvar_id: var_id,
|
|
onceness: onceness,
|
|
capturing_proc: fn_node_id,
|
|
}),
|
|
mutbl: MutabilityCategory::from_def(&def),
|
|
ty: expr_ty
|
|
}))
|
|
}
|
|
_ => {
|
|
self.tcx().sess.span_bug(
|
|
span,
|
|
format!("Upvar of non-closure {} - {}",
|
|
fn_node_id,
|
|
ty.repr(self.tcx())).as_slice());
|
|
}
|
|
}
|
|
}
|
|
|
|
def::DefLocal(vid, _) |
|
|
def::DefBinding(vid, _) => {
|
|
// by-value/by-ref bindings are local variables
|
|
Ok(Rc::new(cmt_ {
|
|
id: id,
|
|
span: span,
|
|
cat: cat_local(vid),
|
|
mutbl: MutabilityCategory::from_def(&def),
|
|
ty: expr_ty
|
|
}))
|
|
}
|
|
}
|
|
}
|
|
|
|
fn cat_upvar(&self,
|
|
id: ast::NodeId,
|
|
span: Span,
|
|
var_id: ast::NodeId,
|
|
fn_node_id: ast::NodeId)
|
|
-> McResult<cmt> {
|
|
/*!
|
|
* Upvars through a closure are in fact indirect
|
|
* references. That is, when a closure refers to a
|
|
* variable from a parent stack frame like `x = 10`,
|
|
* that is equivalent to `*x_ = 10` where `x_` is a
|
|
* borrowed pointer (`&mut x`) created when the closure
|
|
* was created and store in the environment. This
|
|
* equivalence is expose in the mem-categorization.
|
|
*/
|
|
|
|
let upvar_id = ty::UpvarId { var_id: var_id,
|
|
closure_expr_id: fn_node_id };
|
|
|
|
let upvar_borrow = self.typer.upvar_borrow(upvar_id);
|
|
|
|
let var_ty = if_ok!(self.node_ty(var_id));
|
|
|
|
// We can't actually represent the types of all upvars
|
|
// as user-describable types, since upvars support const
|
|
// and unique-imm borrows! Therefore, we cheat, and just
|
|
// give err type. Nobody should be inspecting this type anyhow.
|
|
let upvar_ty = ty::mk_err();
|
|
|
|
let base_cmt = Rc::new(cmt_ {
|
|
id:id,
|
|
span:span,
|
|
cat:cat_upvar(upvar_id, upvar_borrow),
|
|
mutbl:McImmutable,
|
|
ty:upvar_ty,
|
|
});
|
|
|
|
let ptr = BorrowedPtr(upvar_borrow.kind, upvar_borrow.region);
|
|
|
|
let deref_cmt = Rc::new(cmt_ {
|
|
id:id,
|
|
span:span,
|
|
cat:cat_deref(base_cmt, 0, ptr),
|
|
mutbl:MutabilityCategory::from_borrow_kind(upvar_borrow.kind),
|
|
ty:var_ty,
|
|
});
|
|
|
|
Ok(deref_cmt)
|
|
}
|
|
|
|
pub fn cat_rvalue_node(&self,
|
|
id: ast::NodeId,
|
|
span: Span,
|
|
expr_ty: ty::t)
|
|
-> cmt {
|
|
match self.typer.temporary_scope(id) {
|
|
Some(scope) => {
|
|
match ty::get(expr_ty).sty {
|
|
ty::ty_vec(_, Some(0)) => self.cat_rvalue(id, span, ty::ReStatic, expr_ty),
|
|
_ => self.cat_rvalue(id, span, ty::ReScope(scope), expr_ty)
|
|
}
|
|
}
|
|
None => {
|
|
self.cat_rvalue(id, span, ty::ReStatic, expr_ty)
|
|
}
|
|
}
|
|
}
|
|
|
|
pub fn cat_rvalue(&self,
|
|
cmt_id: ast::NodeId,
|
|
span: Span,
|
|
temp_scope: ty::Region,
|
|
expr_ty: ty::t) -> cmt {
|
|
Rc::new(cmt_ {
|
|
id:cmt_id,
|
|
span:span,
|
|
cat:cat_rvalue(temp_scope),
|
|
mutbl:McDeclared,
|
|
ty:expr_ty
|
|
})
|
|
}
|
|
|
|
pub fn cat_field<N:ast_node>(&self,
|
|
node: &N,
|
|
base_cmt: cmt,
|
|
f_name: ast::Ident,
|
|
f_ty: ty::t)
|
|
-> cmt {
|
|
Rc::new(cmt_ {
|
|
id: node.id(),
|
|
span: node.span(),
|
|
mutbl: base_cmt.mutbl.inherit(),
|
|
cat: cat_interior(base_cmt, InteriorField(NamedField(f_name.name))),
|
|
ty: f_ty
|
|
})
|
|
}
|
|
|
|
pub fn cat_deref_obj<N:ast_node>(&self, node: &N, base_cmt: cmt) -> cmt {
|
|
self.cat_deref_common(node, base_cmt, 0, ty::mk_nil(), false)
|
|
}
|
|
|
|
fn cat_deref<N:ast_node>(&self,
|
|
node: &N,
|
|
base_cmt: cmt,
|
|
deref_cnt: uint,
|
|
implicit: bool)
|
|
-> cmt {
|
|
let adjustment = match self.typer.adjustments().borrow().find(&node.id()) {
|
|
Some(adj) if ty::adjust_is_object(adj) => typeck::AutoObject,
|
|
_ if deref_cnt != 0 => typeck::AutoDeref(deref_cnt),
|
|
_ => typeck::NoAdjustment
|
|
};
|
|
|
|
let method_call = typeck::MethodCall {
|
|
expr_id: node.id(),
|
|
adjustment: adjustment
|
|
};
|
|
let method_ty = self.typer.node_method_ty(method_call);
|
|
|
|
debug!("cat_deref: method_call={:?} method_ty={}",
|
|
method_call, method_ty.map(|ty| ty.repr(self.tcx())));
|
|
|
|
let base_cmt = match method_ty {
|
|
Some(method_ty) => {
|
|
let ref_ty = ty::ty_fn_ret(method_ty);
|
|
self.cat_rvalue_node(node.id(), node.span(), ref_ty)
|
|
}
|
|
None => base_cmt
|
|
};
|
|
match ty::deref(base_cmt.ty, true) {
|
|
Some(mt) => self.cat_deref_common(node, base_cmt, deref_cnt, mt.ty, implicit),
|
|
None => {
|
|
self.tcx().sess.span_bug(
|
|
node.span(),
|
|
format!("Explicit deref of non-derefable type: {}",
|
|
base_cmt.ty.repr(self.tcx())).as_slice());
|
|
}
|
|
}
|
|
}
|
|
|
|
fn cat_deref_common<N:ast_node>(&self,
|
|
node: &N,
|
|
base_cmt: cmt,
|
|
deref_cnt: uint,
|
|
deref_ty: ty::t,
|
|
implicit: bool)
|
|
-> cmt {
|
|
let (m, cat) = match deref_kind(self.tcx(), base_cmt.ty) {
|
|
deref_ptr(ptr) => {
|
|
let ptr = if implicit {
|
|
match ptr {
|
|
BorrowedPtr(bk, r) => Implicit(bk, r),
|
|
_ => self.tcx().sess.span_bug(node.span(),
|
|
"Implicit deref of non-borrowed pointer")
|
|
}
|
|
} else {
|
|
ptr
|
|
};
|
|
// for unique ptrs, we inherit mutability from the
|
|
// owning reference.
|
|
(MutabilityCategory::from_pointer_kind(base_cmt.mutbl, ptr),
|
|
cat_deref(base_cmt, deref_cnt, ptr))
|
|
}
|
|
deref_interior(interior) => {
|
|
(base_cmt.mutbl.inherit(), cat_interior(base_cmt, interior))
|
|
}
|
|
};
|
|
Rc::new(cmt_ {
|
|
id: node.id(),
|
|
span: node.span(),
|
|
cat: cat,
|
|
mutbl: m,
|
|
ty: deref_ty
|
|
})
|
|
}
|
|
|
|
pub fn cat_index<N:ast_node>(&self,
|
|
elt: &N,
|
|
mut base_cmt: cmt)
|
|
-> cmt {
|
|
//! Creates a cmt for an indexing operation (`[]`).
|
|
//!
|
|
//! One subtle aspect of indexing that may not be
|
|
//! immediately obvious: for anything other than a fixed-length
|
|
//! vector, an operation like `x[y]` actually consists of two
|
|
//! disjoint (from the point of view of borrowck) operations.
|
|
//! The first is a deref of `x` to create a pointer `p` that points
|
|
//! at the first element in the array. The second operation is
|
|
//! an index which adds `y*sizeof(T)` to `p` to obtain the
|
|
//! pointer to `x[y]`. `cat_index` will produce a resulting
|
|
//! cmt containing both this deref and the indexing,
|
|
//! presuming that `base_cmt` is not of fixed-length type.
|
|
//!
|
|
//! # Parameters
|
|
//! - `elt`: the AST node being indexed
|
|
//! - `base_cmt`: the cmt of `elt`
|
|
|
|
let method_call = typeck::MethodCall::expr(elt.id());
|
|
let method_ty = self.typer.node_method_ty(method_call);
|
|
|
|
let element_ty = match method_ty {
|
|
Some(method_ty) => {
|
|
let ref_ty = ty::ty_fn_ret(method_ty);
|
|
base_cmt = self.cat_rvalue_node(elt.id(), elt.span(), ref_ty);
|
|
*ty::ty_fn_args(method_ty).get(0)
|
|
}
|
|
None => {
|
|
match ty::array_element_ty(base_cmt.ty) {
|
|
Some(ty) => ty,
|
|
None => {
|
|
self.tcx().sess.span_bug(
|
|
elt.span(),
|
|
format!("Explicit index of non-index type `{}`",
|
|
base_cmt.ty.repr(self.tcx())).as_slice());
|
|
}
|
|
}
|
|
}
|
|
};
|
|
|
|
let m = base_cmt.mutbl.inherit();
|
|
return interior(elt, base_cmt.clone(), base_cmt.ty, m, element_ty);
|
|
|
|
fn interior<N: ast_node>(elt: &N,
|
|
of_cmt: cmt,
|
|
vec_ty: ty::t,
|
|
mutbl: MutabilityCategory,
|
|
element_ty: ty::t) -> cmt
|
|
{
|
|
Rc::new(cmt_ {
|
|
id:elt.id(),
|
|
span:elt.span(),
|
|
cat:cat_interior(of_cmt, InteriorElement(element_kind(vec_ty))),
|
|
mutbl:mutbl,
|
|
ty:element_ty
|
|
})
|
|
}
|
|
}
|
|
|
|
// Takes either a vec or a reference to a vec and returns the cmt for the
|
|
// underlying vec.
|
|
fn deref_vec<N:ast_node>(&self,
|
|
elt: &N,
|
|
base_cmt: cmt)
|
|
-> cmt {
|
|
match deref_kind(self.tcx(), base_cmt.ty) {
|
|
deref_ptr(ptr) => {
|
|
// for unique ptrs, we inherit mutability from the
|
|
// owning reference.
|
|
let m = MutabilityCategory::from_pointer_kind(base_cmt.mutbl, ptr);
|
|
|
|
// the deref is explicit in the resulting cmt
|
|
Rc::new(cmt_ {
|
|
id:elt.id(),
|
|
span:elt.span(),
|
|
cat:cat_deref(base_cmt.clone(), 0, ptr),
|
|
mutbl:m,
|
|
ty: match ty::deref(base_cmt.ty, false) {
|
|
Some(mt) => mt.ty,
|
|
None => self.tcx().sess.bug("Found non-derefable type")
|
|
}
|
|
})
|
|
}
|
|
|
|
deref_interior(_) => {
|
|
base_cmt
|
|
}
|
|
}
|
|
}
|
|
|
|
pub fn cat_slice_pattern(&self,
|
|
vec_cmt: cmt,
|
|
slice_pat: &ast::Pat)
|
|
-> McResult<(cmt, ast::Mutability, ty::Region)> {
|
|
/*!
|
|
* Given a pattern P like: `[_, ..Q, _]`, where `vec_cmt` is
|
|
* the cmt for `P`, `slice_pat` is the pattern `Q`, returns:
|
|
* - a cmt for `Q`
|
|
* - the mutability and region of the slice `Q`
|
|
*
|
|
* These last two bits of info happen to be things that
|
|
* borrowck needs.
|
|
*/
|
|
|
|
let slice_ty = if_ok!(self.node_ty(slice_pat.id));
|
|
let (slice_mutbl, slice_r) = vec_slice_info(self.tcx(),
|
|
slice_pat,
|
|
slice_ty);
|
|
let cmt_slice = self.cat_index(slice_pat, self.deref_vec(slice_pat, vec_cmt));
|
|
return Ok((cmt_slice, slice_mutbl, slice_r));
|
|
|
|
fn vec_slice_info(tcx: &ty::ctxt,
|
|
pat: &ast::Pat,
|
|
slice_ty: ty::t)
|
|
-> (ast::Mutability, ty::Region) {
|
|
/*!
|
|
* In a pattern like [a, b, ..c], normally `c` has slice type,
|
|
* but if you have [a, b, ..ref c], then the type of `ref c`
|
|
* will be `&&[]`, so to extract the slice details we have
|
|
* to recurse through rptrs.
|
|
*/
|
|
|
|
match ty::get(slice_ty).sty {
|
|
ty::ty_rptr(r, ref mt) => match ty::get(mt.ty).sty {
|
|
ty::ty_vec(_, None) => (mt.mutbl, r),
|
|
_ => vec_slice_info(tcx, pat, mt.ty),
|
|
},
|
|
|
|
_ => {
|
|
tcx.sess.span_bug(pat.span,
|
|
"type of slice pattern is not a slice");
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
pub fn cat_imm_interior<N:ast_node>(&self,
|
|
node: &N,
|
|
base_cmt: cmt,
|
|
interior_ty: ty::t,
|
|
interior: InteriorKind)
|
|
-> cmt {
|
|
Rc::new(cmt_ {
|
|
id: node.id(),
|
|
span: node.span(),
|
|
mutbl: base_cmt.mutbl.inherit(),
|
|
cat: cat_interior(base_cmt, interior),
|
|
ty: interior_ty
|
|
})
|
|
}
|
|
|
|
pub fn cat_downcast<N:ast_node>(&self,
|
|
node: &N,
|
|
base_cmt: cmt,
|
|
downcast_ty: ty::t)
|
|
-> cmt {
|
|
Rc::new(cmt_ {
|
|
id: node.id(),
|
|
span: node.span(),
|
|
mutbl: base_cmt.mutbl.inherit(),
|
|
cat: cat_downcast(base_cmt),
|
|
ty: downcast_ty
|
|
})
|
|
}
|
|
|
|
pub fn cat_pattern(&self,
|
|
cmt: cmt,
|
|
pat: &ast::Pat,
|
|
op: |&MemCategorizationContext<TYPER>,
|
|
cmt,
|
|
&ast::Pat|)
|
|
-> McResult<()> {
|
|
// Here, `cmt` is the categorization for the value being
|
|
// matched and pat is the pattern it is being matched against.
|
|
//
|
|
// In general, the way that this works is that we walk down
|
|
// the pattern, constructing a cmt that represents the path
|
|
// that will be taken to reach the value being matched.
|
|
//
|
|
// When we encounter named bindings, we take the cmt that has
|
|
// been built up and pass it off to guarantee_valid() so that
|
|
// we can be sure that the binding will remain valid for the
|
|
// duration of the arm.
|
|
//
|
|
// (*2) There is subtlety concerning the correspondence between
|
|
// pattern ids and types as compared to *expression* ids and
|
|
// types. This is explained briefly. on the definition of the
|
|
// type `cmt`, so go off and read what it says there, then
|
|
// come back and I'll dive into a bit more detail here. :) OK,
|
|
// back?
|
|
//
|
|
// In general, the id of the cmt should be the node that
|
|
// "produces" the value---patterns aren't executable code
|
|
// exactly, but I consider them to "execute" when they match a
|
|
// value, and I consider them to produce the value that was
|
|
// matched. So if you have something like:
|
|
//
|
|
// let x = @@3;
|
|
// match x {
|
|
// @@y { ... }
|
|
// }
|
|
//
|
|
// In this case, the cmt and the relevant ids would be:
|
|
//
|
|
// CMT Id Type of Id Type of cmt
|
|
//
|
|
// local(x)->@->@
|
|
// ^~~~~~~^ `x` from discr @@int @@int
|
|
// ^~~~~~~~~~^ `@@y` pattern node @@int @int
|
|
// ^~~~~~~~~~~~~^ `@y` pattern node @int int
|
|
//
|
|
// You can see that the types of the id and the cmt are in
|
|
// sync in the first line, because that id is actually the id
|
|
// of an expression. But once we get to pattern ids, the types
|
|
// step out of sync again. So you'll see below that we always
|
|
// get the type of the *subpattern* and use that.
|
|
|
|
debug!("cat_pattern: id={} pat={} cmt={}",
|
|
pat.id, pprust::pat_to_string(pat),
|
|
cmt.repr(self.tcx()));
|
|
|
|
op(self, cmt.clone(), pat);
|
|
|
|
match pat.node {
|
|
ast::PatWild(_) => {
|
|
// _
|
|
}
|
|
|
|
ast::PatEnum(_, None) => {
|
|
// variant(..)
|
|
}
|
|
ast::PatEnum(_, Some(ref subpats)) => {
|
|
match self.tcx().def_map.borrow().find(&pat.id) {
|
|
Some(&def::DefVariant(enum_did, _, _)) => {
|
|
// variant(x, y, z)
|
|
|
|
let downcast_cmt = {
|
|
if ty::enum_is_univariant(self.tcx(), enum_did) {
|
|
cmt // univariant, no downcast needed
|
|
} else {
|
|
self.cat_downcast(pat, cmt.clone(), cmt.ty)
|
|
}
|
|
};
|
|
|
|
for (i, subpat) in subpats.iter().enumerate() {
|
|
let subpat_ty = if_ok!(self.pat_ty(&**subpat)); // see (*2)
|
|
|
|
let subcmt =
|
|
self.cat_imm_interior(
|
|
pat, downcast_cmt.clone(), subpat_ty,
|
|
InteriorField(PositionalField(i)));
|
|
|
|
if_ok!(self.cat_pattern(subcmt, &**subpat, |x,y,z| op(x,y,z)));
|
|
}
|
|
}
|
|
Some(&def::DefFn(..)) |
|
|
Some(&def::DefStruct(..)) => {
|
|
for (i, subpat) in subpats.iter().enumerate() {
|
|
let subpat_ty = if_ok!(self.pat_ty(&**subpat)); // see (*2)
|
|
let cmt_field =
|
|
self.cat_imm_interior(
|
|
pat, cmt.clone(), subpat_ty,
|
|
InteriorField(PositionalField(i)));
|
|
if_ok!(self.cat_pattern(cmt_field, &**subpat,
|
|
|x,y,z| op(x,y,z)));
|
|
}
|
|
}
|
|
Some(&def::DefStatic(..)) => {
|
|
for subpat in subpats.iter() {
|
|
if_ok!(self.cat_pattern(cmt.clone(), &**subpat, |x,y,z| op(x,y,z)));
|
|
}
|
|
}
|
|
_ => {
|
|
self.tcx().sess.span_bug(
|
|
pat.span,
|
|
"enum pattern didn't resolve to enum or struct");
|
|
}
|
|
}
|
|
}
|
|
|
|
ast::PatIdent(_, _, Some(ref subpat)) => {
|
|
if_ok!(self.cat_pattern(cmt, &**subpat, op));
|
|
}
|
|
|
|
ast::PatIdent(_, _, None) => {
|
|
// nullary variant or identifier: ignore
|
|
}
|
|
|
|
ast::PatStruct(_, ref field_pats, _) => {
|
|
// {f1: p1, ..., fN: pN}
|
|
for fp in field_pats.iter() {
|
|
let field_ty = if_ok!(self.pat_ty(&*fp.pat)); // see (*2)
|
|
let cmt_field = self.cat_field(pat, cmt.clone(), fp.ident, field_ty);
|
|
if_ok!(self.cat_pattern(cmt_field, &*fp.pat, |x,y,z| op(x,y,z)));
|
|
}
|
|
}
|
|
|
|
ast::PatTup(ref subpats) => {
|
|
// (p1, ..., pN)
|
|
for (i, subpat) in subpats.iter().enumerate() {
|
|
let subpat_ty = if_ok!(self.pat_ty(&**subpat)); // see (*2)
|
|
let subcmt =
|
|
self.cat_imm_interior(
|
|
pat, cmt.clone(), subpat_ty,
|
|
InteriorField(PositionalField(i)));
|
|
if_ok!(self.cat_pattern(subcmt, &**subpat, |x,y,z| op(x,y,z)));
|
|
}
|
|
}
|
|
|
|
ast::PatBox(ref subpat) | ast::PatRegion(ref subpat) => {
|
|
// @p1, ~p1, ref p1
|
|
let subcmt = self.cat_deref(pat, cmt, 0, false);
|
|
if_ok!(self.cat_pattern(subcmt, &**subpat, op));
|
|
}
|
|
|
|
ast::PatVec(ref before, slice, ref after) => {
|
|
let elt_cmt = self.cat_index(pat, self.deref_vec(pat, cmt));
|
|
for before_pat in before.iter() {
|
|
if_ok!(self.cat_pattern(elt_cmt.clone(), &**before_pat,
|
|
|x,y,z| op(x,y,z)));
|
|
}
|
|
for slice_pat in slice.iter() {
|
|
let slice_ty = if_ok!(self.pat_ty(&**slice_pat));
|
|
let slice_cmt = self.cat_rvalue_node(pat.id(), pat.span(), slice_ty);
|
|
if_ok!(self.cat_pattern(slice_cmt, &**slice_pat, |x,y,z| op(x,y,z)));
|
|
}
|
|
for after_pat in after.iter() {
|
|
if_ok!(self.cat_pattern(elt_cmt.clone(), &**after_pat, |x,y,z| op(x,y,z)));
|
|
}
|
|
}
|
|
|
|
ast::PatLit(_) | ast::PatRange(_, _) => {
|
|
/*always ok*/
|
|
}
|
|
|
|
ast::PatMac(_) => {
|
|
self.tcx().sess.span_bug(pat.span, "unexpanded macro");
|
|
}
|
|
}
|
|
|
|
Ok(())
|
|
}
|
|
|
|
pub fn cmt_to_string(&self, cmt: &cmt_) -> String {
|
|
match cmt.cat {
|
|
cat_static_item => {
|
|
"static item".to_string()
|
|
}
|
|
cat_copied_upvar(_) => {
|
|
"captured outer variable in a proc".to_string()
|
|
}
|
|
cat_rvalue(..) => {
|
|
"non-lvalue".to_string()
|
|
}
|
|
cat_local(_) => {
|
|
"local variable".to_string()
|
|
}
|
|
cat_arg(..) => {
|
|
"argument".to_string()
|
|
}
|
|
cat_deref(ref base, _, pk) => {
|
|
match base.cat {
|
|
cat_upvar(..) => {
|
|
"captured outer variable".to_string()
|
|
}
|
|
_ => {
|
|
match pk {
|
|
Implicit(..) => {
|
|
"dereference (dereference is implicit, due to indexing)".to_string()
|
|
}
|
|
OwnedPtr | GcPtr => format!("dereference of `{}`", ptr_sigil(pk)),
|
|
_ => format!("dereference of `{}`-pointer", ptr_sigil(pk))
|
|
}
|
|
}
|
|
}
|
|
}
|
|
cat_interior(_, InteriorField(NamedField(_))) => {
|
|
"field".to_string()
|
|
}
|
|
cat_interior(_, InteriorField(PositionalField(_))) => {
|
|
"anonymous field".to_string()
|
|
}
|
|
cat_interior(_, InteriorElement(VecElement)) => {
|
|
"vec content".to_string()
|
|
}
|
|
cat_interior(_, InteriorElement(OtherElement)) => {
|
|
"indexed content".to_string()
|
|
}
|
|
cat_upvar(..) => {
|
|
"captured outer variable".to_string()
|
|
}
|
|
cat_discr(ref cmt, _) => {
|
|
self.cmt_to_string(&**cmt)
|
|
}
|
|
cat_downcast(ref cmt) => {
|
|
self.cmt_to_string(&**cmt)
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
pub enum InteriorSafety {
|
|
InteriorUnsafe,
|
|
InteriorSafe
|
|
}
|
|
|
|
pub enum AliasableReason {
|
|
AliasableManaged,
|
|
AliasableBorrowed,
|
|
AliasableOther,
|
|
AliasableStatic(InteriorSafety),
|
|
AliasableStaticMut(InteriorSafety),
|
|
}
|
|
|
|
impl cmt_ {
|
|
pub fn guarantor(&self) -> cmt {
|
|
//! Returns `self` after stripping away any owned pointer derefs or
|
|
//! interior content. The return value is basically the `cmt` which
|
|
//! determines how long the value in `self` remains live.
|
|
|
|
match self.cat {
|
|
cat_rvalue(..) |
|
|
cat_static_item |
|
|
cat_copied_upvar(..) |
|
|
cat_local(..) |
|
|
cat_arg(..) |
|
|
cat_deref(_, _, UnsafePtr(..)) |
|
|
cat_deref(_, _, GcPtr(..)) |
|
|
cat_deref(_, _, BorrowedPtr(..)) |
|
|
cat_deref(_, _, Implicit(..)) |
|
|
cat_upvar(..) => {
|
|
Rc::new((*self).clone())
|
|
}
|
|
cat_downcast(ref b) |
|
|
cat_discr(ref b, _) |
|
|
cat_interior(ref b, _) |
|
|
cat_deref(ref b, _, OwnedPtr) => {
|
|
b.guarantor()
|
|
}
|
|
}
|
|
}
|
|
|
|
pub fn freely_aliasable(&self, ctxt: &ty::ctxt) -> Option<AliasableReason> {
|
|
/*!
|
|
* Returns `Some(_)` if this lvalue represents a freely aliasable
|
|
* pointer type.
|
|
*/
|
|
|
|
// Maybe non-obvious: copied upvars can only be considered
|
|
// non-aliasable in once closures, since any other kind can be
|
|
// aliased and eventually recused.
|
|
|
|
match self.cat {
|
|
cat_deref(ref b, _, BorrowedPtr(ty::MutBorrow, _)) |
|
|
cat_deref(ref b, _, Implicit(ty::MutBorrow, _)) |
|
|
cat_deref(ref b, _, BorrowedPtr(ty::UniqueImmBorrow, _)) |
|
|
cat_deref(ref b, _, Implicit(ty::UniqueImmBorrow, _)) |
|
|
cat_downcast(ref b) |
|
|
cat_deref(ref b, _, OwnedPtr) |
|
|
cat_interior(ref b, _) |
|
|
cat_discr(ref b, _) => {
|
|
// Aliasability depends on base cmt
|
|
b.freely_aliasable(ctxt)
|
|
}
|
|
|
|
cat_copied_upvar(CopiedUpvar {onceness: ast::Once, ..}) |
|
|
cat_rvalue(..) |
|
|
cat_local(..) |
|
|
cat_upvar(..) |
|
|
cat_arg(_) |
|
|
cat_deref(_, _, UnsafePtr(..)) => { // yes, it's aliasable, but...
|
|
None
|
|
}
|
|
|
|
cat_copied_upvar(CopiedUpvar {onceness: ast::Many, ..}) => {
|
|
Some(AliasableOther)
|
|
}
|
|
|
|
cat_static_item(..) => {
|
|
let int_safe = if ty::type_interior_is_unsafe(ctxt, self.ty) {
|
|
InteriorUnsafe
|
|
} else {
|
|
InteriorSafe
|
|
};
|
|
|
|
if self.mutbl.is_mutable() {
|
|
Some(AliasableStaticMut(int_safe))
|
|
} else {
|
|
Some(AliasableStatic(int_safe))
|
|
}
|
|
}
|
|
|
|
cat_deref(_, _, GcPtr) => {
|
|
Some(AliasableManaged)
|
|
}
|
|
|
|
cat_deref(_, _, BorrowedPtr(ty::ImmBorrow, _)) |
|
|
cat_deref(_, _, Implicit(ty::ImmBorrow, _)) => {
|
|
Some(AliasableBorrowed)
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
impl Repr for cmt_ {
|
|
fn repr(&self, tcx: &ty::ctxt) -> String {
|
|
format!("{{{} id:{} m:{:?} ty:{}}}",
|
|
self.cat.repr(tcx),
|
|
self.id,
|
|
self.mutbl,
|
|
self.ty.repr(tcx))
|
|
}
|
|
}
|
|
|
|
impl Repr for categorization {
|
|
fn repr(&self, tcx: &ty::ctxt) -> String {
|
|
match *self {
|
|
cat_static_item |
|
|
cat_rvalue(..) |
|
|
cat_copied_upvar(..) |
|
|
cat_local(..) |
|
|
cat_upvar(..) |
|
|
cat_arg(..) => {
|
|
format!("{:?}", *self)
|
|
}
|
|
cat_deref(ref cmt, derefs, ptr) => {
|
|
format!("{}-{}{}->", cmt.cat.repr(tcx), ptr_sigil(ptr), derefs)
|
|
}
|
|
cat_interior(ref cmt, interior) => {
|
|
format!("{}.{}", cmt.cat.repr(tcx), interior.repr(tcx))
|
|
}
|
|
cat_downcast(ref cmt) => {
|
|
format!("{}->(enum)", cmt.cat.repr(tcx))
|
|
}
|
|
cat_discr(ref cmt, _) => {
|
|
cmt.cat.repr(tcx)
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
pub fn ptr_sigil(ptr: PointerKind) -> &'static str {
|
|
match ptr {
|
|
OwnedPtr => "Box",
|
|
GcPtr => "Gc",
|
|
BorrowedPtr(ty::ImmBorrow, _) |
|
|
Implicit(ty::ImmBorrow, _) => "&",
|
|
BorrowedPtr(ty::MutBorrow, _) |
|
|
Implicit(ty::MutBorrow, _) => "&mut",
|
|
BorrowedPtr(ty::UniqueImmBorrow, _) |
|
|
Implicit(ty::UniqueImmBorrow, _) => "&unique",
|
|
UnsafePtr(_) => "*"
|
|
}
|
|
}
|
|
|
|
impl Repr for InteriorKind {
|
|
fn repr(&self, _tcx: &ty::ctxt) -> String {
|
|
match *self {
|
|
InteriorField(NamedField(fld)) => {
|
|
token::get_name(fld).get().to_string()
|
|
}
|
|
InteriorField(PositionalField(i)) => format!("#{:?}", i),
|
|
InteriorElement(_) => "[]".to_string(),
|
|
}
|
|
}
|
|
}
|
|
|
|
fn element_kind(t: ty::t) -> ElementKind {
|
|
match ty::get(t).sty {
|
|
ty::ty_rptr(_, ty::mt{ty:ty, ..}) |
|
|
ty::ty_uniq(ty) => match ty::get(ty).sty {
|
|
ty::ty_vec(_, None) => VecElement,
|
|
_ => OtherElement
|
|
},
|
|
ty::ty_vec(..) => VecElement,
|
|
_ => OtherElement
|
|
}
|
|
}
|