264 lines
8.6 KiB
Rust
264 lines
8.6 KiB
Rust
// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use driver::session::Session;
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use middle::resolve;
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use middle::ty;
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use middle::typeck;
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use util::ppaux;
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use syntax::ast::*;
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use syntax::codemap;
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use syntax::{visit, ast_util, ast_map};
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pub fn check_crate(sess: Session,
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crate: @crate,
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ast_map: ast_map::map,
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def_map: resolve::DefMap,
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method_map: typeck::method_map,
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tcx: ty::ctxt) {
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visit::visit_crate(crate, false, visit::mk_vt(@visit::Visitor {
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visit_item: |a,b,c| check_item(sess, ast_map, def_map, a, b, c),
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visit_pat: check_pat,
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visit_expr: |a,b,c|
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check_expr(sess, def_map, method_map, tcx, a, b, c),
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.. *visit::default_visitor()
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}));
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sess.abort_if_errors();
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}
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pub fn check_item(sess: Session,
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ast_map: ast_map::map,
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def_map: resolve::DefMap,
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it: @item,
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_is_const: bool,
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v: visit::vt<bool>) {
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match it.node {
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item_const(_, ex) => {
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(v.visit_expr)(ex, true, v);
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check_item_recursion(sess, ast_map, def_map, it);
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}
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item_enum(ref enum_definition, _) => {
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for (*enum_definition).variants.each |var| {
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for var.node.disr_expr.each |ex| {
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(v.visit_expr)(*ex, true, v);
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}
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}
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}
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_ => visit::visit_item(it, false, v)
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}
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}
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pub fn check_pat(p: @pat, _is_const: bool, v: visit::vt<bool>) {
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fn is_str(e: @expr) -> bool {
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match e.node {
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expr_vstore(
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@expr { node: expr_lit(@codemap::spanned {
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node: lit_str(_),
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_}),
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_ },
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expr_vstore_uniq
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) => true,
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_ => false
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}
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}
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match p.node {
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// Let through plain ~-string literals here
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pat_lit(a) => if !is_str(a) { (v.visit_expr)(a, true, v); },
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pat_range(a, b) => {
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if !is_str(a) { (v.visit_expr)(a, true, v); }
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if !is_str(b) { (v.visit_expr)(b, true, v); }
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}
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_ => visit::visit_pat(p, false, v)
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}
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}
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pub fn check_expr(sess: Session,
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def_map: resolve::DefMap,
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method_map: typeck::method_map,
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tcx: ty::ctxt,
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e: @expr,
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is_const: bool,
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v: visit::vt<bool>) {
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if is_const {
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match e.node {
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expr_unary(deref, _) => { }
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expr_unary(box(_), _) | expr_unary(uniq(_), _) => {
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sess.span_err(e.span,
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~"disallowed operator in constant expression");
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return;
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}
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expr_lit(@codemap::spanned {node: lit_str(_), _}) => { }
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expr_binary(_, _, _) | expr_unary(_, _) => {
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if method_map.contains_key(&e.id) {
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sess.span_err(e.span, ~"user-defined operators are not \
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allowed in constant expressions");
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}
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}
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expr_lit(_) => (),
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expr_cast(_, _) => {
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let ety = ty::expr_ty(tcx, e);
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if !ty::type_is_numeric(ety) && !ty::type_is_unsafe_ptr(ety) {
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sess.span_err(e.span, ~"can not cast to `" +
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ppaux::ty_to_str(tcx, ety) +
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~"` in a constant expression");
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}
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}
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expr_path(pth) => {
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// NB: In the future you might wish to relax this slightly
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// to handle on-demand instantiation of functions via
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// foo::<bar> in a const. Currently that is only done on
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// a path in trans::callee that only works in block contexts.
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if pth.types.len() != 0 {
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sess.span_err(
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e.span, ~"paths in constants may only refer to \
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items without type parameters");
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}
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match def_map.find(&e.id) {
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Some(&def_const(_)) |
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Some(&def_fn(_, _)) |
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Some(&def_variant(_, _)) |
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Some(&def_struct(_)) => { }
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Some(&def) => {
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debug!("(checking const) found bad def: %?", def);
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sess.span_err(
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e.span,
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fmt!("paths in constants may only refer to \
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constants or functions"));
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}
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None => {
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sess.span_bug(e.span, ~"unbound path in const?!");
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}
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}
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}
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expr_call(callee, _, NoSugar) => {
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match def_map.find(&callee.id) {
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Some(&def_struct(*)) => {} // OK.
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Some(&def_variant(*)) => {} // OK.
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_ => {
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sess.span_err(
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e.span,
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~"function calls in constants are limited to \
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struct and enum constructors");
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}
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}
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}
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expr_paren(e) => { check_expr(sess, def_map, method_map,
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tcx, e, is_const, v); }
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expr_vstore(_, expr_vstore_slice) |
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expr_vec(_, m_imm) |
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expr_addr_of(m_imm, _) |
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expr_field(*) |
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expr_index(*) |
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expr_tup(*) |
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expr_struct(_, _, None) => { }
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expr_addr_of(*) => {
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sess.span_err(
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e.span,
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~"borrowed pointers in constants may only refer to \
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immutable values");
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}
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_ => {
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sess.span_err(e.span,
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~"constant contains unimplemented expression type");
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return;
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}
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}
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}
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match e.node {
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expr_lit(@codemap::spanned {node: lit_int(v, t), _}) => {
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if t != ty_char {
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if (v as u64) > ast_util::int_ty_max(
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if t == ty_i { sess.targ_cfg.int_type } else { t }) {
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sess.span_err(e.span, ~"literal out of range for its type");
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}
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}
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}
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expr_lit(@codemap::spanned {node: lit_uint(v, t), _}) => {
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if v > ast_util::uint_ty_max(
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if t == ty_u { sess.targ_cfg.uint_type } else { t }) {
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sess.span_err(e.span, ~"literal out of range for its type");
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}
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}
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_ => ()
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}
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visit::visit_expr(e, is_const, v);
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}
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// Make sure a const item doesn't recursively refer to itself
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// FIXME: Should use the dependency graph when it's available (#1356)
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pub fn check_item_recursion(sess: Session,
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ast_map: ast_map::map,
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def_map: resolve::DefMap,
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it: @item) {
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struct env {
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root_it: @item,
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sess: Session,
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ast_map: ast_map::map,
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def_map: resolve::DefMap,
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idstack: @mut ~[node_id]
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}
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let env = env {
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root_it: it,
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sess: sess,
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ast_map: ast_map,
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def_map: def_map,
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idstack: @mut ~[]
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};
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let visitor = visit::mk_vt(@visit::Visitor {
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visit_item: visit_item,
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visit_expr: visit_expr,
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.. *visit::default_visitor()
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});
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(visitor.visit_item)(it, env, visitor);
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fn visit_item(it: @item, env: env, v: visit::vt<env>) {
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if env.idstack.contains(&(it.id)) {
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env.sess.span_fatal(env.root_it.span, ~"recursive constant");
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}
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env.idstack.push(it.id);
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visit::visit_item(it, env, v);
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env.idstack.pop();
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}
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fn visit_expr(e: @expr, env: env, v: visit::vt<env>) {
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match e.node {
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expr_path(*) => {
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match env.def_map.find(&e.id) {
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Some(&def_const(def_id)) => {
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if ast_util::is_local(def_id) {
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match *env.ast_map.get(&def_id.node) {
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ast_map::node_item(it, _) => {
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(v.visit_item)(it, env, v);
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}
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_ => fail!(~"const not bound to an item")
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}
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}
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}
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_ => ()
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}
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}
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_ => ()
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}
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visit::visit_expr(e, env, v);
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}
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}
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// Local Variables:
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// mode: rust
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// fill-column: 78;
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// indent-tabs-mode: nil
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// c-basic-offset: 4
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// buffer-file-coding-system: utf-8-unix
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// End:
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