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rustc: Determine regions for locals

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This commit is contained in:
Patrick Walton 2012-03-11 12:36:56 -07:00
parent e968672ac7
commit f7efc29b38
2 changed files with 49 additions and 2 deletions
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8
src/rustc/middle/regionck.rs
View File

@ -8,6 +8,14 @@ import middle::ty;
import std::map::hashmap;
import syntax::{ast, visit};
// An "extended region", which includes the ordinarily-unnamed reference-
// counted heap and exchange heap regions. This is used to detect borrowing.
enum region_ext {
re_rc,
re_exheap,
re_region(ty::region)
}
type ctxt = {
tcx: ty::ctxt,
enclosing_block: option<ast::node_id>

43
src/rustc/middle/typeck.rs
View File

@ -1848,6 +1848,45 @@ fn lookup_field_ty(cx: ty::ctxt, items:[@ast::class_item],
cx.sess.span_fatal(sp, #fmt("unbound field %s", fieldname));
}
/*
* Returns the region that the value named by the given expression lives in.
* If the expression is not an lvalue, reports an error and returns the block
* region.
*
* Note that borrowing is not detected here, because we would have to
* immediately structurally resolve too many types otherwise. Thus the
* reference-counted heap and exchange heap regions will be reported as block
* regions instead. This is cleaned up in the region checking pass.
*/
fn region_of(fcx: @fn_ctxt, expr: @ast::expr) -> ty::region {
alt expr.node {
ast::expr_path(path) {
let defn = lookup_def(fcx, path.span, expr.id);
alt defn {
ast::def_local(local_id, _) |
ast::def_upvar(local_id, _, _) {
let local_blocks = fcx.ccx.tcx.region_map.local_blocks;
let local_block_id = local_blocks.get(local_id);
ret ty::re_block(local_block_id);
}
_ {
fcx.ccx.tcx.sess.span_unimpl(expr.span,
"immortal region");
}
}
}
ast::expr_field(base, _, _) | ast::expr_index(base, _) |
ast::expr_unary(ast::deref, base) {
fcx.ccx.tcx.sess.span_unimpl(expr.span, "regions of field, " +
"index, or deref operations");
}
_ {
fcx.ccx.tcx.sess.span_err(expr.span, "not an lvalue");
ret ty::re_block(0);
}
}
}
fn check_expr_fn_with_unifier(fcx: @fn_ctxt,
expr: @ast::expr,
proto: ast::proto,
@ -2202,9 +2241,9 @@ fn check_expr_with_unifier(fcx: @fn_ctxt, expr: @ast::expr, unify: unifier,
bot = check_expr(fcx, oper);
let oper_t = expr_ty(tcx, oper);
// FIXME: This is incorrect. Infer the proper region.
let region = region_of(fcx, oper);
let tm = { ty: oper_t, mutbl: mutbl };
oper_t = ty::mk_rptr(tcx, ty::re_block(0), tm);
oper_t = ty::mk_rptr(tcx, region, tm);
write_ty(tcx, id, oper_t);
}
ast::expr_path(pth) {