1032 lines
34 KiB
Rust
1032 lines
34 KiB
Rust
/*!
|
|
* # Categorization
|
|
*
|
|
* The job of the categorization module is to analyze an expression to
|
|
* determine what kind of memory is used in evaluating it (for example,
|
|
* where dereferences occur and what kind of pointer is dereferenced;
|
|
* whether the memory is mutable; etc)
|
|
*
|
|
* Categorization effectively transforms all of our expressions into
|
|
* expressions of the following forms (the actual enum has many more
|
|
* possibilities, naturally, but they are all variants of these base
|
|
* forms):
|
|
*
|
|
* E = rvalue // some computed rvalue
|
|
* | x // address of a local variable, arg, or upvar
|
|
* | *E // deref of a ptr
|
|
* | E.comp // access to an interior component
|
|
*
|
|
* Imagine a routine ToAddr(Expr) that evaluates an expression and returns an
|
|
* address where the result is to be found. If Expr is an lvalue, then this
|
|
* is the address of the lvalue. If Expr is an rvalue, this is the address of
|
|
* some temporary spot in memory where the result is stored.
|
|
*
|
|
* Now, cat_expr() classies the expression Expr and the address A=ToAddr(Expr)
|
|
* as follows:
|
|
*
|
|
* - cat: what kind of expression was this? This is a subset of the
|
|
* full expression forms which only includes those that we care about
|
|
* for the purpose of the analysis.
|
|
* - mutbl: mutability of the address A
|
|
* - ty: the type of data found at the address A
|
|
*
|
|
* The resulting categorization tree differs somewhat from the expressions
|
|
* themselves. For example, auto-derefs are explicit. Also, an index a[b] is
|
|
* decomposed into two operations: a derefence to reach the array data and
|
|
* then an index to jump forward to the relevant item.
|
|
*/
|
|
|
|
use syntax::ast;
|
|
use syntax::ast::{m_imm, m_const, m_mutbl};
|
|
use syntax::codemap::span;
|
|
use syntax::print::pprust;
|
|
use util::ppaux::{ty_to_str, region_to_str};
|
|
use util::common::indenter;
|
|
|
|
enum categorization {
|
|
cat_rvalue, // result of eval'ing some misc expr
|
|
cat_special(special_kind), //
|
|
cat_local(ast::node_id), // local variable
|
|
cat_binding(ast::node_id), // pattern binding
|
|
cat_arg(ast::node_id), // formal argument
|
|
cat_stack_upvar(cmt), // upvar in stack closure
|
|
cat_deref(cmt, uint, ptr_kind), // deref of a ptr
|
|
cat_comp(cmt, comp_kind), // adjust to locate an internal component
|
|
cat_discr(cmt, ast::node_id), // match discriminant (see preserve())
|
|
}
|
|
|
|
impl categorization : cmp::Eq {
|
|
pure fn eq(other: &categorization) -> bool {
|
|
match self {
|
|
cat_rvalue => {
|
|
match (*other) {
|
|
cat_rvalue => true,
|
|
_ => false
|
|
}
|
|
}
|
|
cat_special(e0a) => {
|
|
match (*other) {
|
|
cat_special(e0b) => e0a == e0b,
|
|
_ => false
|
|
}
|
|
}
|
|
cat_local(e0a) => {
|
|
match (*other) {
|
|
cat_local(e0b) => e0a == e0b,
|
|
_ => false
|
|
}
|
|
}
|
|
cat_binding(e0a) => {
|
|
match (*other) {
|
|
cat_binding(e0b) => e0a == e0b,
|
|
_ => false
|
|
}
|
|
}
|
|
cat_arg(e0a) => {
|
|
match (*other) {
|
|
cat_arg(e0b) => e0a == e0b,
|
|
_ => false
|
|
}
|
|
}
|
|
cat_stack_upvar(e0a) => {
|
|
match (*other) {
|
|
cat_stack_upvar(e0b) => e0a == e0b,
|
|
_ => false
|
|
}
|
|
}
|
|
cat_deref(e0a, e1a, e2a) => {
|
|
match (*other) {
|
|
cat_deref(e0b, e1b, e2b) =>
|
|
e0a == e0b && e1a == e1b && e2a == e2b,
|
|
_ => false
|
|
}
|
|
}
|
|
cat_comp(e0a, e1a) => {
|
|
match (*other) {
|
|
cat_comp(e0b, e1b) => e0a == e0b && e1a == e1b,
|
|
_ => false
|
|
}
|
|
}
|
|
cat_discr(e0a, e1a) => {
|
|
match (*other) {
|
|
cat_discr(e0b, e1b) => e0a == e0b && e1a == e1b,
|
|
_ => false
|
|
}
|
|
}
|
|
}
|
|
}
|
|
pure fn ne(other: &categorization) -> bool { !self.eq(other) }
|
|
}
|
|
|
|
// different kinds of pointers:
|
|
enum ptr_kind {
|
|
uniq_ptr,
|
|
gc_ptr,
|
|
region_ptr(ty::region),
|
|
unsafe_ptr
|
|
}
|
|
|
|
impl ptr_kind : cmp::Eq {
|
|
pure fn eq(other: &ptr_kind) -> bool {
|
|
match self {
|
|
uniq_ptr => {
|
|
match (*other) {
|
|
uniq_ptr => true,
|
|
_ => false
|
|
}
|
|
}
|
|
gc_ptr => {
|
|
match (*other) {
|
|
gc_ptr => true,
|
|
_ => false
|
|
}
|
|
}
|
|
region_ptr(e0a) => {
|
|
match (*other) {
|
|
region_ptr(e0b) => e0a == e0b,
|
|
_ => false
|
|
}
|
|
}
|
|
unsafe_ptr => {
|
|
match (*other) {
|
|
unsafe_ptr => true,
|
|
_ => false
|
|
}
|
|
}
|
|
}
|
|
}
|
|
pure fn ne(other: &ptr_kind) -> bool { !self.eq(other) }
|
|
}
|
|
|
|
// I am coining the term "components" to mean "pieces of a data
|
|
// structure accessible without a dereference":
|
|
enum comp_kind {
|
|
comp_tuple, // elt in a tuple
|
|
comp_variant(ast::def_id), // internals to a variant of given enum
|
|
comp_field(ast::ident, // name of field
|
|
ast::mutability), // declared mutability of field
|
|
comp_index(ty::t, // type of vec/str/etc being deref'd
|
|
ast::mutability) // mutability of vec content
|
|
}
|
|
|
|
impl comp_kind : cmp::Eq {
|
|
pure fn eq(other: &comp_kind) -> bool {
|
|
match self {
|
|
comp_tuple => {
|
|
match (*other) {
|
|
comp_tuple => true,
|
|
_ => false
|
|
}
|
|
}
|
|
comp_variant(e0a) => {
|
|
match (*other) {
|
|
comp_variant(e0b) => e0a == e0b,
|
|
_ => false
|
|
}
|
|
}
|
|
comp_field(e0a, e1a) => {
|
|
match (*other) {
|
|
comp_field(e0b, e1b) => e0a == e0b && e1a == e1b,
|
|
_ => false
|
|
}
|
|
}
|
|
comp_index(e0a, e1a) => {
|
|
match (*other) {
|
|
comp_index(e0b, e1b) => e0a == e0b && e1a == e1b,
|
|
_ => false
|
|
}
|
|
}
|
|
}
|
|
}
|
|
pure fn ne(other: &comp_kind) -> bool { !self.eq(other) }
|
|
}
|
|
|
|
// different kinds of expressions we might evaluate
|
|
enum special_kind {
|
|
sk_method,
|
|
sk_static_item,
|
|
sk_self,
|
|
sk_heap_upvar
|
|
}
|
|
|
|
impl special_kind : cmp::Eq {
|
|
pure fn eq(other: &special_kind) -> bool {
|
|
(self as uint) == ((*other) as uint)
|
|
}
|
|
pure fn ne(other: &special_kind) -> bool { !self.eq(other) }
|
|
}
|
|
|
|
// a complete categorization of a value indicating where it originated
|
|
// and how it is located, as well as the mutability of the memory in
|
|
// which the value is stored.
|
|
type cmt_ = {id: ast::node_id, // id of expr/pat producing this value
|
|
span: span, // span of same expr/pat
|
|
cat: categorization, // categorization of expr
|
|
lp: Option<@loan_path>, // loan path for expr, if any
|
|
mutbl: ast::mutability, // mutability of expr as lvalue
|
|
ty: ty::t}; // type of the expr
|
|
|
|
type cmt = @cmt_;
|
|
|
|
impl cmt_ : cmp::Eq {
|
|
pure fn eq(other: &cmt_) -> bool {
|
|
self.id == (*other).id &&
|
|
self.span == (*other).span &&
|
|
self.cat == (*other).cat &&
|
|
self.lp == (*other).lp &&
|
|
self.mutbl == (*other).mutbl &&
|
|
self.ty == (*other).ty
|
|
}
|
|
pure fn ne(other: &cmt_) -> bool { !self.eq(other) }
|
|
}
|
|
|
|
// a loan path is like a category, but it exists only when the data is
|
|
// interior to the stack frame. loan paths are used as the key to a
|
|
// map indicating what is borrowed at any point in time.
|
|
enum loan_path {
|
|
lp_local(ast::node_id),
|
|
lp_arg(ast::node_id),
|
|
lp_deref(@loan_path, ptr_kind),
|
|
lp_comp(@loan_path, comp_kind)
|
|
}
|
|
|
|
impl loan_path : cmp::Eq {
|
|
pure fn eq(other: &loan_path) -> bool {
|
|
match self {
|
|
lp_local(e0a) => {
|
|
match (*other) {
|
|
lp_local(e0b) => e0a == e0b,
|
|
_ => false
|
|
}
|
|
}
|
|
lp_arg(e0a) => {
|
|
match (*other) {
|
|
lp_arg(e0b) => e0a == e0b,
|
|
_ => false
|
|
}
|
|
}
|
|
lp_deref(e0a, e1a) => {
|
|
match (*other) {
|
|
lp_deref(e0b, e1b) => e0a == e0b && e1a == e1b,
|
|
_ => false
|
|
}
|
|
}
|
|
lp_comp(e0a, e1a) => {
|
|
match (*other) {
|
|
lp_comp(e0b, e1b) => e0a == e0b && e1a == e1b,
|
|
_ => false
|
|
}
|
|
}
|
|
}
|
|
}
|
|
pure fn ne(other: &loan_path) -> bool { !self.eq(other) }
|
|
}
|
|
|
|
// We pun on *T to mean both actual deref of a ptr as well
|
|
// as accessing of components:
|
|
enum deref_kind {deref_ptr(ptr_kind), deref_comp(comp_kind)}
|
|
|
|
// Categorizes a derefable type. Note that we include vectors and strings as
|
|
// derefable (we model an index as the combination of a deref and then a
|
|
// pointer adjustment).
|
|
fn opt_deref_kind(t: ty::t) -> Option<deref_kind> {
|
|
match ty::get(t).sty {
|
|
ty::ty_uniq(*) |
|
|
ty::ty_evec(_, ty::vstore_uniq) |
|
|
ty::ty_estr(ty::vstore_uniq) => {
|
|
Some(deref_ptr(uniq_ptr))
|
|
}
|
|
|
|
ty::ty_rptr(r, _) |
|
|
ty::ty_evec(_, ty::vstore_slice(r)) |
|
|
ty::ty_estr(ty::vstore_slice(r)) => {
|
|
Some(deref_ptr(region_ptr(r)))
|
|
}
|
|
|
|
ty::ty_box(*) |
|
|
ty::ty_evec(_, ty::vstore_box) |
|
|
ty::ty_estr(ty::vstore_box) => {
|
|
Some(deref_ptr(gc_ptr))
|
|
}
|
|
|
|
ty::ty_ptr(*) => {
|
|
Some(deref_ptr(unsafe_ptr))
|
|
}
|
|
|
|
ty::ty_enum(did, _) => {
|
|
Some(deref_comp(comp_variant(did)))
|
|
}
|
|
|
|
ty::ty_evec(mt, ty::vstore_fixed(_)) => {
|
|
Some(deref_comp(comp_index(t, mt.mutbl)))
|
|
}
|
|
|
|
ty::ty_estr(ty::vstore_fixed(_)) => {
|
|
Some(deref_comp(comp_index(t, m_imm)))
|
|
}
|
|
|
|
_ => None
|
|
}
|
|
}
|
|
|
|
fn deref_kind(tcx: ty::ctxt, t: ty::t) -> deref_kind {
|
|
match opt_deref_kind(t) {
|
|
Some(k) => k,
|
|
None => {
|
|
tcx.sess.bug(
|
|
fmt!("deref_cat() invoked on non-derefable type %s",
|
|
ty_to_str(tcx, t)));
|
|
}
|
|
}
|
|
}
|
|
|
|
fn cat_expr(
|
|
tcx: ty::ctxt,
|
|
method_map: typeck::method_map,
|
|
expr: @ast::expr) -> cmt {
|
|
|
|
let mcx = &mem_categorization_ctxt {
|
|
tcx: tcx, method_map: method_map
|
|
};
|
|
return mcx.cat_expr(expr);
|
|
}
|
|
|
|
fn cat_def(
|
|
tcx: ty::ctxt,
|
|
method_map: typeck::method_map,
|
|
expr_id: ast::node_id,
|
|
expr_span: span,
|
|
expr_ty: ty::t,
|
|
def: ast::def) -> cmt {
|
|
|
|
let mcx = &mem_categorization_ctxt {
|
|
tcx: tcx, method_map: method_map
|
|
};
|
|
return mcx.cat_def(expr_id, expr_span, expr_ty, def);
|
|
}
|
|
|
|
fn cat_variant<N: ast_node>(
|
|
tcx: ty::ctxt,
|
|
method_map: typeck::method_map,
|
|
arg: N,
|
|
enum_did: ast::def_id,
|
|
cmt: cmt) -> cmt {
|
|
|
|
let mcx = &mem_categorization_ctxt {
|
|
tcx: tcx, method_map: method_map
|
|
};
|
|
return mcx.cat_variant(arg, enum_did, cmt);
|
|
}
|
|
|
|
trait ast_node {
|
|
fn id() -> ast::node_id;
|
|
fn span() -> span;
|
|
}
|
|
|
|
impl @ast::expr: ast_node {
|
|
fn id() -> ast::node_id { self.id }
|
|
fn span() -> span { self.span }
|
|
}
|
|
|
|
impl @ast::pat: ast_node {
|
|
fn id() -> ast::node_id { self.id }
|
|
fn span() -> span { self.span }
|
|
}
|
|
|
|
trait get_type_for_node {
|
|
fn ty<N: ast_node>(node: N) -> ty::t;
|
|
}
|
|
|
|
impl ty::ctxt: get_type_for_node {
|
|
fn ty<N: ast_node>(node: N) -> ty::t {
|
|
ty::node_id_to_type(self, node.id())
|
|
}
|
|
}
|
|
|
|
struct mem_categorization_ctxt {
|
|
tcx: ty::ctxt,
|
|
method_map: typeck::method_map,
|
|
}
|
|
|
|
impl &mem_categorization_ctxt {
|
|
fn cat_expr(expr: @ast::expr) -> cmt {
|
|
match self.tcx.adjustments.find(expr.id) {
|
|
None => {
|
|
// No adjustments.
|
|
self.cat_expr_unadjusted(expr)
|
|
}
|
|
|
|
Some(adjustment) => {
|
|
match adjustment.autoref {
|
|
Some(_) => {
|
|
// Equivalent to &*expr or something similar.
|
|
// This is an rvalue, effectively.
|
|
let expr_ty = ty::expr_ty(self.tcx, expr);
|
|
self.cat_rvalue(expr, expr_ty)
|
|
}
|
|
None => {
|
|
// Equivalent to *expr or something similar.
|
|
self.cat_expr_autoderefd(expr, adjustment)
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
fn cat_expr_autoderefd(expr: @ast::expr,
|
|
adjustment: &ty::AutoAdjustment) -> cmt {
|
|
let mut cmt = self.cat_expr_unadjusted(expr);
|
|
for uint::range(1, adjustment.autoderefs+1) |deref| {
|
|
cmt = self.cat_deref(expr, cmt, deref);
|
|
}
|
|
return cmt;
|
|
}
|
|
|
|
fn cat_expr_unadjusted(expr: @ast::expr) -> cmt {
|
|
debug!("cat_expr: id=%d expr=%s",
|
|
expr.id, pprust::expr_to_str(expr, self.tcx.sess.intr()));
|
|
|
|
let tcx = self.tcx;
|
|
let expr_ty = tcx.ty(expr);
|
|
match expr.node {
|
|
ast::expr_unary(ast::deref, e_base) => {
|
|
if self.method_map.contains_key(expr.id) {
|
|
return self.cat_rvalue(expr, expr_ty);
|
|
}
|
|
|
|
let base_cmt = self.cat_expr(e_base);
|
|
self.cat_deref(expr, base_cmt, 0)
|
|
}
|
|
|
|
ast::expr_field(base, f_name, _) => {
|
|
if self.method_map.contains_key(expr.id) {
|
|
return self.cat_method_ref(expr, expr_ty);
|
|
}
|
|
|
|
let base_cmt = self.cat_expr(base);
|
|
self.cat_field(expr, base_cmt, f_name)
|
|
}
|
|
|
|
ast::expr_index(base, _) => {
|
|
if self.method_map.contains_key(expr.id) {
|
|
return self.cat_rvalue(expr, expr_ty);
|
|
}
|
|
|
|
let base_cmt = self.cat_expr(base);
|
|
self.cat_index(expr, base_cmt)
|
|
}
|
|
|
|
ast::expr_path(_) => {
|
|
let def = self.tcx.def_map.get(expr.id);
|
|
self.cat_def(expr.id, expr.span, expr_ty, def)
|
|
}
|
|
|
|
ast::expr_addr_of(*) | ast::expr_call(*) |
|
|
ast::expr_swap(*) | ast::expr_move(*) | ast::expr_assign(*) |
|
|
ast::expr_assign_op(*) | ast::expr_fn(*) | ast::expr_fn_block(*) |
|
|
ast::expr_assert(*) | ast::expr_ret(*) |
|
|
ast::expr_loop_body(*) | ast::expr_do_body(*) | ast::expr_unary(*) |
|
|
ast::expr_copy(*) | ast::expr_cast(*) | ast::expr_fail(*) |
|
|
ast::expr_vstore(*) | ast::expr_vec(*) | ast::expr_tup(*) |
|
|
ast::expr_if(*) | ast::expr_log(*) |
|
|
ast::expr_binary(*) | ast::expr_while(*) |
|
|
ast::expr_block(*) | ast::expr_loop(*) | ast::expr_match(*) |
|
|
ast::expr_lit(*) | ast::expr_break(*) | ast::expr_mac(*) |
|
|
ast::expr_again(*) | ast::expr_rec(*) | ast::expr_struct(*) |
|
|
ast::expr_unary_move(*) | ast::expr_repeat(*) => {
|
|
return self.cat_rvalue(expr, expr_ty);
|
|
}
|
|
}
|
|
}
|
|
|
|
fn cat_def(id: ast::node_id,
|
|
span: span,
|
|
expr_ty: ty::t,
|
|
def: ast::def) -> cmt {
|
|
match def {
|
|
ast::def_fn(*) | ast::def_static_method(*) | ast::def_mod(_) |
|
|
ast::def_foreign_mod(_) | ast::def_const(_) |
|
|
ast::def_use(_) | ast::def_variant(*) |
|
|
ast::def_ty(_) | ast::def_prim_ty(_) |
|
|
ast::def_ty_param(*) | ast::def_class(*) |
|
|
ast::def_typaram_binder(*) | ast::def_region(_) |
|
|
ast::def_label(_) => {
|
|
@{id:id, span:span,
|
|
cat:cat_special(sk_static_item), lp:None,
|
|
mutbl:m_imm, ty:expr_ty}
|
|
}
|
|
|
|
ast::def_arg(vid, mode) => {
|
|
// Idea: make this could be rewritten to model by-ref
|
|
// stuff as `&const` and `&mut`?
|
|
|
|
// m: mutability of the argument
|
|
// lp: loan path, must be none for aliasable things
|
|
let {m,lp} = match ty::resolved_mode(self.tcx, mode) {
|
|
ast::by_mutbl_ref => {
|
|
{m: m_mutbl, lp: None}
|
|
}
|
|
ast::by_move | ast::by_copy => {
|
|
{m: m_imm, lp: Some(@lp_arg(vid))}
|
|
}
|
|
ast::by_ref => {
|
|
{m: m_imm, lp: None}
|
|
}
|
|
ast::by_val => {
|
|
// by-value is this hybrid mode where we have a
|
|
// pointer but we do not own it. This is not
|
|
// considered loanable because, for example, a by-ref
|
|
// and and by-val argument might both actually contain
|
|
// the same unique ptr.
|
|
{m: m_imm, lp: None}
|
|
}
|
|
};
|
|
@{id:id, span:span,
|
|
cat:cat_arg(vid), lp:lp,
|
|
mutbl:m, ty:expr_ty}
|
|
}
|
|
|
|
ast::def_self(_) => {
|
|
@{id:id, span:span,
|
|
cat:cat_special(sk_self), lp:None,
|
|
mutbl:m_imm, ty:expr_ty}
|
|
}
|
|
|
|
ast::def_upvar(_, inner, fn_node_id, _) => {
|
|
let ty = ty::node_id_to_type(self.tcx, fn_node_id);
|
|
let proto = ty::ty_fn_proto(ty);
|
|
match proto {
|
|
ty::proto_vstore(ty::vstore_slice(_)) => {
|
|
let upcmt = self.cat_def(id, span, expr_ty, *inner);
|
|
@{id:id, span:span,
|
|
cat:cat_stack_upvar(upcmt), lp:upcmt.lp,
|
|
mutbl:upcmt.mutbl, ty:upcmt.ty}
|
|
}
|
|
ty::proto_bare |
|
|
ty::proto_vstore(ty::vstore_uniq) |
|
|
ty::proto_vstore(ty::vstore_box) => {
|
|
// FIXME #2152 allow mutation of moved upvars
|
|
@{id:id, span:span,
|
|
cat:cat_special(sk_heap_upvar), lp:None,
|
|
mutbl:m_imm, ty:expr_ty}
|
|
}
|
|
ty::proto_vstore(ty::vstore_fixed(_)) =>
|
|
fail ~"fixed vstore not allowed here"
|
|
}
|
|
}
|
|
|
|
ast::def_local(vid, mutbl) => {
|
|
let m = if mutbl {m_mutbl} else {m_imm};
|
|
@{id:id, span:span,
|
|
cat:cat_local(vid), lp:Some(@lp_local(vid)),
|
|
mutbl:m, ty:expr_ty}
|
|
}
|
|
|
|
ast::def_binding(vid, ast::bind_by_value) |
|
|
ast::def_binding(vid, ast::bind_by_move) |
|
|
ast::def_binding(vid, ast::bind_by_ref(_)) => {
|
|
// by-value/by-ref bindings are local variables
|
|
@{id:id, span:span,
|
|
cat:cat_local(vid), lp:Some(@lp_local(vid)),
|
|
mutbl:m_imm, ty:expr_ty}
|
|
}
|
|
|
|
ast::def_binding(pid, ast::bind_by_implicit_ref) => {
|
|
// implicit-by-ref bindings are "special" since they are
|
|
// implicit pointers.
|
|
|
|
// Technically, the mutability is not always imm, but we
|
|
// (choose to be) unsound for the moment since these
|
|
// implicit refs are going away and it reduces external
|
|
// dependencies.
|
|
|
|
@{id:id, span:span,
|
|
cat:cat_binding(pid), lp:None,
|
|
mutbl:m_imm, ty:expr_ty}
|
|
}
|
|
}
|
|
}
|
|
|
|
fn cat_variant<N: ast_node>(arg: N,
|
|
enum_did: ast::def_id,
|
|
cmt: cmt) -> cmt {
|
|
@{id: arg.id(), span: arg.span(),
|
|
cat: cat_comp(cmt, comp_variant(enum_did)),
|
|
lp: cmt.lp.map(|l| @lp_comp(*l, comp_variant(enum_did)) ),
|
|
mutbl: cmt.mutbl, // imm iff in an immutable context
|
|
ty: self.tcx.ty(arg)}
|
|
}
|
|
|
|
fn cat_rvalue(expr: @ast::expr, expr_ty: ty::t) -> cmt {
|
|
@{id:expr.id, span:expr.span,
|
|
cat:cat_rvalue, lp:None,
|
|
mutbl:m_imm, ty:expr_ty}
|
|
}
|
|
|
|
/// inherited mutability: used in cases where the mutability of a
|
|
/// component is inherited from the base it is a part of. For
|
|
/// example, a record field is mutable if it is declared mutable
|
|
/// or if the container is mutable.
|
|
fn inherited_mutability(base_m: ast::mutability,
|
|
comp_m: ast::mutability) -> ast::mutability {
|
|
match comp_m {
|
|
m_imm => {base_m} // imm: as mutable as the container
|
|
m_mutbl | m_const => {comp_m}
|
|
}
|
|
}
|
|
|
|
fn cat_field<N:ast_node>(node: N, base_cmt: cmt,
|
|
f_name: ast::ident) -> cmt {
|
|
let f_mutbl = match field_mutbl(self.tcx, base_cmt.ty, f_name) {
|
|
Some(f_mutbl) => f_mutbl,
|
|
None => {
|
|
self.tcx.sess.span_bug(
|
|
node.span(),
|
|
fmt!("Cannot find field `%s` in type `%s`",
|
|
self.tcx.sess.str_of(f_name),
|
|
ty_to_str(self.tcx, base_cmt.ty)));
|
|
}
|
|
};
|
|
let m = self.inherited_mutability(base_cmt.mutbl, f_mutbl);
|
|
let f_comp = comp_field(f_name, f_mutbl);
|
|
let lp = base_cmt.lp.map(|lp| @lp_comp(*lp, f_comp) );
|
|
@{id: node.id(), span: node.span(),
|
|
cat: cat_comp(base_cmt, f_comp), lp:lp,
|
|
mutbl: m, ty: self.tcx.ty(node)}
|
|
}
|
|
|
|
fn cat_deref<N:ast_node>(node: N,
|
|
base_cmt: cmt,
|
|
deref_cnt: uint) -> cmt {
|
|
let mt = match ty::deref(self.tcx, base_cmt.ty, true) {
|
|
Some(mt) => mt,
|
|
None => {
|
|
self.tcx.sess.span_bug(
|
|
node.span(),
|
|
fmt!("Explicit deref of non-derefable type: %s",
|
|
ty_to_str(self.tcx, base_cmt.ty)));
|
|
}
|
|
};
|
|
|
|
match deref_kind(self.tcx, base_cmt.ty) {
|
|
deref_ptr(ptr) => {
|
|
let lp = do base_cmt.lp.chain_ref |l| {
|
|
// Given that the ptr itself is loanable, we can
|
|
// loan out deref'd uniq ptrs as the data they are
|
|
// the only way to reach the data they point at.
|
|
// Other ptr types admit aliases and are therefore
|
|
// not loanable.
|
|
match ptr {
|
|
uniq_ptr => {Some(@lp_deref(*l, ptr))}
|
|
gc_ptr | region_ptr(_) | unsafe_ptr => {None}
|
|
}
|
|
};
|
|
|
|
// for unique ptrs, we inherit mutability from the
|
|
// owning reference.
|
|
let m = match ptr {
|
|
uniq_ptr => {
|
|
self.inherited_mutability(base_cmt.mutbl, mt.mutbl)
|
|
}
|
|
gc_ptr | region_ptr(_) | unsafe_ptr => {
|
|
mt.mutbl
|
|
}
|
|
};
|
|
|
|
@{id:node.id(), span:node.span(),
|
|
cat:cat_deref(base_cmt, deref_cnt, ptr), lp:lp,
|
|
mutbl:m, ty:mt.ty}
|
|
}
|
|
|
|
deref_comp(comp) => {
|
|
let lp = base_cmt.lp.map(|l| @lp_comp(*l, comp) );
|
|
let m = self.inherited_mutability(base_cmt.mutbl, mt.mutbl);
|
|
@{id:node.id(), span:node.span(),
|
|
cat:cat_comp(base_cmt, comp), lp:lp,
|
|
mutbl:m, ty:mt.ty}
|
|
}
|
|
}
|
|
}
|
|
|
|
fn cat_index(expr: @ast::expr, base_cmt: cmt) -> cmt {
|
|
let mt = match ty::index(self.tcx, base_cmt.ty) {
|
|
Some(mt) => mt,
|
|
None => {
|
|
self.tcx.sess.span_bug(
|
|
expr.span,
|
|
fmt!("Explicit index of non-index type `%s`",
|
|
ty_to_str(self.tcx, base_cmt.ty)));
|
|
}
|
|
};
|
|
|
|
return match deref_kind(self.tcx, base_cmt.ty) {
|
|
deref_ptr(ptr) => {
|
|
// (a) the contents are loanable if the base is loanable
|
|
// and this is a *unique* vector
|
|
let deref_lp = match ptr {
|
|
uniq_ptr => {base_cmt.lp.map(|lp| @lp_deref(*lp, uniq_ptr))}
|
|
_ => {None}
|
|
};
|
|
|
|
// (b) for unique ptrs, we inherit mutability from the
|
|
// owning reference.
|
|
let m = match ptr {
|
|
uniq_ptr => {
|
|
self.inherited_mutability(base_cmt.mutbl, mt.mutbl)
|
|
}
|
|
gc_ptr | region_ptr(_) | unsafe_ptr => {
|
|
mt.mutbl
|
|
}
|
|
};
|
|
|
|
// (c) the deref is explicit in the resulting cmt
|
|
let deref_cmt = @{id:expr.id, span:expr.span,
|
|
cat:cat_deref(base_cmt, 0u, ptr), lp:deref_lp,
|
|
mutbl:m, ty:mt.ty};
|
|
|
|
comp(expr, deref_cmt, base_cmt.ty, m, mt.ty)
|
|
}
|
|
|
|
deref_comp(_) => {
|
|
// fixed-length vectors have no deref
|
|
comp(expr, base_cmt, base_cmt.ty, mt.mutbl, mt.ty)
|
|
}
|
|
};
|
|
|
|
fn comp(expr: @ast::expr, of_cmt: cmt,
|
|
vect: ty::t, mutbl: ast::mutability, ty: ty::t) -> cmt {
|
|
let comp = comp_index(vect, mutbl);
|
|
let index_lp = of_cmt.lp.map(|lp| @lp_comp(*lp, comp) );
|
|
@{id:expr.id, span:expr.span,
|
|
cat:cat_comp(of_cmt, comp), lp:index_lp,
|
|
mutbl:mutbl, ty:ty}
|
|
}
|
|
}
|
|
|
|
fn cat_tuple_elt<N: ast_node>(elt: N, cmt: cmt) -> cmt {
|
|
@{id: elt.id(), span: elt.span(),
|
|
cat: cat_comp(cmt, comp_tuple),
|
|
lp: cmt.lp.map(|l| @lp_comp(*l, comp_tuple) ),
|
|
mutbl: cmt.mutbl, // imm iff in an immutable context
|
|
ty: self.tcx.ty(elt)}
|
|
}
|
|
|
|
fn cat_method_ref(expr: @ast::expr, expr_ty: ty::t) -> cmt {
|
|
@{id:expr.id, span:expr.span,
|
|
cat:cat_special(sk_method), lp:None,
|
|
mutbl:m_imm, ty:expr_ty}
|
|
}
|
|
|
|
fn cat_pattern(cmt: cmt, pat: @ast::pat, op: fn(cmt, @ast::pat)) {
|
|
|
|
op(cmt, pat);
|
|
|
|
// 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.
|
|
//
|
|
// The correspondence between the id in the cmt and which
|
|
// pattern is being referred to is somewhat...subtle. In
|
|
// general, the id of the cmt is the id of the node that
|
|
// produces the value. For patterns, that's actually the
|
|
// *subpattern*, generally speaking.
|
|
//
|
|
// To see what I mean about ids etc, consider:
|
|
//
|
|
// let x = @@3;
|
|
// match x {
|
|
// @@y { ... }
|
|
// }
|
|
//
|
|
// Here the cmt for `y` would be something like
|
|
//
|
|
// local(x)->@->@
|
|
//
|
|
// where the id of `local(x)` is the id of the `x` that appears
|
|
// in the alt, the id of `local(x)->@` is the `@y` pattern,
|
|
// and the id of `local(x)->@->@` is the id of the `y` pattern.
|
|
|
|
|
|
let _i = indenter();
|
|
let tcx = self.tcx;
|
|
debug!("cat_pattern: id=%d pat=%s cmt=%s",
|
|
pat.id, pprust::pat_to_str(pat, tcx.sess.intr()),
|
|
self.cmt_to_repr(cmt));
|
|
|
|
match pat.node {
|
|
ast::pat_wild => {
|
|
// _
|
|
}
|
|
|
|
ast::pat_enum(_, None) => {
|
|
// variant(*)
|
|
}
|
|
ast::pat_enum(_, Some(subpats)) => {
|
|
// variant(x, y, z)
|
|
let enum_did = match self.tcx.def_map.find(pat.id) {
|
|
Some(ast::def_variant(enum_did, _)) => enum_did,
|
|
e => tcx.sess.span_bug(pat.span,
|
|
fmt!("resolved to %?, not variant", e))
|
|
};
|
|
|
|
for subpats.each |subpat| {
|
|
let subcmt = self.cat_variant(*subpat, enum_did, cmt);
|
|
self.cat_pattern(subcmt, *subpat, op);
|
|
}
|
|
}
|
|
|
|
ast::pat_ident(_, _, Some(subpat)) => {
|
|
self.cat_pattern(cmt, subpat, op);
|
|
}
|
|
|
|
ast::pat_ident(_, _, None) => {
|
|
// nullary variant or identifier: ignore
|
|
}
|
|
|
|
ast::pat_rec(field_pats, _) => {
|
|
// {f1: p1, ..., fN: pN}
|
|
for field_pats.each |fp| {
|
|
let cmt_field = self.cat_field(fp.pat, cmt, fp.ident);
|
|
self.cat_pattern(cmt_field, fp.pat, op);
|
|
}
|
|
}
|
|
|
|
ast::pat_struct(_, field_pats, _) => {
|
|
// {f1: p1, ..., fN: pN}
|
|
for field_pats.each |fp| {
|
|
let cmt_field = self.cat_field(fp.pat, cmt, fp.ident);
|
|
self.cat_pattern(cmt_field, fp.pat, op);
|
|
}
|
|
}
|
|
|
|
ast::pat_tup(subpats) => {
|
|
// (p1, ..., pN)
|
|
for subpats.each |subpat| {
|
|
let subcmt = self.cat_tuple_elt(*subpat, cmt);
|
|
self.cat_pattern(subcmt, *subpat, op);
|
|
}
|
|
}
|
|
|
|
ast::pat_box(subpat) | ast::pat_uniq(subpat) |
|
|
ast::pat_region(subpat) => {
|
|
// @p1, ~p1
|
|
let subcmt = self.cat_deref(subpat, cmt, 0);
|
|
self.cat_pattern(subcmt, subpat, op);
|
|
}
|
|
|
|
ast::pat_lit(_) | ast::pat_range(_, _) => { /*always ok*/ }
|
|
}
|
|
}
|
|
|
|
fn cat_to_repr(cat: categorization) -> ~str {
|
|
match cat {
|
|
cat_special(sk_method) => ~"method",
|
|
cat_special(sk_static_item) => ~"static_item",
|
|
cat_special(sk_self) => ~"self",
|
|
cat_special(sk_heap_upvar) => ~"heap-upvar",
|
|
cat_stack_upvar(_) => ~"stack-upvar",
|
|
cat_rvalue => ~"rvalue",
|
|
cat_local(node_id) => fmt!("local(%d)", node_id),
|
|
cat_binding(node_id) => fmt!("binding(%d)", node_id),
|
|
cat_arg(node_id) => fmt!("arg(%d)", node_id),
|
|
cat_deref(cmt, derefs, ptr) => {
|
|
fmt!("%s->(%s, %u)", self.cat_to_repr(cmt.cat),
|
|
self.ptr_sigil(ptr), derefs)
|
|
}
|
|
cat_comp(cmt, comp) => {
|
|
fmt!("%s.%s", self.cat_to_repr(cmt.cat), self.comp_to_repr(comp))
|
|
}
|
|
cat_discr(cmt, _) => self.cat_to_repr(cmt.cat)
|
|
}
|
|
}
|
|
|
|
fn mut_to_str(mutbl: ast::mutability) -> ~str {
|
|
match mutbl {
|
|
m_mutbl => ~"mutable",
|
|
m_const => ~"const",
|
|
m_imm => ~"immutable"
|
|
}
|
|
}
|
|
|
|
fn ptr_sigil(ptr: ptr_kind) -> ~str {
|
|
match ptr {
|
|
uniq_ptr => ~"~",
|
|
gc_ptr => ~"@",
|
|
region_ptr(_) => ~"&",
|
|
unsafe_ptr => ~"*"
|
|
}
|
|
}
|
|
|
|
fn comp_to_repr(comp: comp_kind) -> ~str {
|
|
match comp {
|
|
comp_field(fld, _) => self.tcx.sess.str_of(fld),
|
|
comp_index(*) => ~"[]",
|
|
comp_tuple => ~"()",
|
|
comp_variant(_) => ~"<enum>"
|
|
}
|
|
}
|
|
|
|
fn lp_to_str(lp: @loan_path) -> ~str {
|
|
match *lp {
|
|
lp_local(node_id) => {
|
|
fmt!("local(%d)", node_id)
|
|
}
|
|
lp_arg(node_id) => {
|
|
fmt!("arg(%d)", node_id)
|
|
}
|
|
lp_deref(lp, ptr) => {
|
|
fmt!("%s->(%s)", self.lp_to_str(lp),
|
|
self.ptr_sigil(ptr))
|
|
}
|
|
lp_comp(lp, comp) => {
|
|
fmt!("%s.%s", self.lp_to_str(lp),
|
|
self.comp_to_repr(comp))
|
|
}
|
|
}
|
|
}
|
|
|
|
fn cmt_to_repr(cmt: cmt) -> ~str {
|
|
fmt!("{%s id:%d m:%s lp:%s ty:%s}",
|
|
self.cat_to_repr(cmt.cat),
|
|
cmt.id,
|
|
self.mut_to_str(cmt.mutbl),
|
|
cmt.lp.map_default(~"none", |p| self.lp_to_str(*p) ),
|
|
ty_to_str(self.tcx, cmt.ty))
|
|
}
|
|
|
|
fn cmt_to_str(cmt: cmt) -> ~str {
|
|
let mut_str = self.mut_to_str(cmt.mutbl);
|
|
match cmt.cat {
|
|
cat_special(sk_method) => ~"method",
|
|
cat_special(sk_static_item) => ~"static item",
|
|
cat_special(sk_self) => ~"self reference",
|
|
cat_special(sk_heap_upvar) => {
|
|
~"captured outer variable in a heap closure"
|
|
}
|
|
cat_rvalue => ~"non-lvalue",
|
|
cat_local(_) => mut_str + ~" local variable",
|
|
cat_binding(_) => ~"pattern binding",
|
|
cat_arg(_) => ~"argument",
|
|
cat_deref(_, _, pk) => fmt!("dereference of %s %s pointer",
|
|
mut_str, self.ptr_sigil(pk)),
|
|
cat_stack_upvar(_) => {
|
|
~"captured outer " + mut_str + ~" variable in a stack closure"
|
|
}
|
|
cat_comp(_, comp_field(*)) => mut_str + ~" field",
|
|
cat_comp(_, comp_tuple) => ~"tuple content",
|
|
cat_comp(_, comp_variant(_)) => ~"enum content",
|
|
cat_comp(_, comp_index(t, _)) => {
|
|
match ty::get(t).sty {
|
|
ty::ty_evec(*) => mut_str + ~" vec content",
|
|
ty::ty_estr(*) => mut_str + ~" str content",
|
|
_ => mut_str + ~" indexed content"
|
|
}
|
|
}
|
|
cat_discr(cmt, _) => {
|
|
self.cmt_to_str(cmt)
|
|
}
|
|
}
|
|
}
|
|
|
|
fn region_to_str(r: ty::region) -> ~str {
|
|
region_to_str(self.tcx, r)
|
|
}
|
|
}
|
|
|
|
fn field_mutbl(tcx: ty::ctxt,
|
|
base_ty: ty::t,
|
|
f_name: ast::ident) -> Option<ast::mutability> {
|
|
// Need to refactor so that records/class fields can be treated uniformly.
|
|
match ty::get(base_ty).sty {
|
|
ty::ty_rec(fields) => {
|
|
for fields.each |f| {
|
|
if f.ident == f_name {
|
|
return Some(f.mt.mutbl);
|
|
}
|
|
}
|
|
}
|
|
ty::ty_class(did, _) => {
|
|
for ty::lookup_class_fields(tcx, did).each |fld| {
|
|
if fld.ident == f_name {
|
|
let m = match fld.mutability {
|
|
ast::class_mutable => ast::m_mutbl,
|
|
ast::class_immutable => ast::m_imm
|
|
};
|
|
return Some(m);
|
|
}
|
|
}
|
|
}
|
|
_ => { }
|
|
}
|
|
|
|
return None;
|
|
}
|