1236 lines
49 KiB
Rust
1236 lines
49 KiB
Rust
// Copyright 2012-2015 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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//#![allow(non_camel_case_types)]
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use self::ConstVal::*;
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use self::ErrKind::*;
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use self::EvalHint::*;
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use front::map as ast_map;
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use front::map::blocks::FnLikeNode;
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use middle::cstore::{self, CrateStore, InlinedItem};
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use middle::{infer, subst, traits};
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use middle::def::Def;
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use middle::def_id::DefId;
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use middle::pat_util::def_to_path;
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use middle::ty::{self, Ty, TyCtxt};
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use middle::ty::util::IntTypeExt;
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use middle::traits::ProjectionMode;
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use middle::astconv_util::ast_ty_to_prim_ty;
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use util::nodemap::NodeMap;
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use graphviz::IntoCow;
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use syntax::ast;
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use rustc_front::hir::{Expr, PatKind};
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use rustc_front::hir;
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use rustc_front::intravisit::FnKind;
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use syntax::codemap::Span;
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use syntax::parse::token::InternedString;
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use syntax::ptr::P;
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use syntax::codemap;
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use syntax::attr::IntType;
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use std::borrow::Cow;
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use std::cmp::Ordering;
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use std::collections::hash_map::Entry::Vacant;
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use std::hash;
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use std::mem::transmute;
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use std::rc::Rc;
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use rustc_const_eval::*;
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macro_rules! math {
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($e:expr, $op:expr) => {
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match $op {
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Ok(val) => val,
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Err(e) => signal!($e, Math(e)),
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}
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}
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}
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fn lookup_variant_by_id<'a>(tcx: &'a ty::TyCtxt,
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enum_def: DefId,
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variant_def: DefId)
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-> Option<&'a Expr> {
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fn variant_expr<'a>(variants: &'a [hir::Variant], id: ast::NodeId)
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-> Option<&'a Expr> {
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for variant in variants {
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if variant.node.data.id() == id {
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return variant.node.disr_expr.as_ref().map(|e| &**e);
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}
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}
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None
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}
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if let Some(enum_node_id) = tcx.map.as_local_node_id(enum_def) {
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let variant_node_id = tcx.map.as_local_node_id(variant_def).unwrap();
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match tcx.map.find(enum_node_id) {
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None => None,
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Some(ast_map::NodeItem(it)) => match it.node {
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hir::ItemEnum(hir::EnumDef { ref variants }, _) => {
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variant_expr(variants, variant_node_id)
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}
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_ => None
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},
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Some(_) => None
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}
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} else {
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None
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}
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}
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/// * `def_id` is the id of the constant.
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/// * `substs` is the monomorphized substitutions for the expression.
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///
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/// `substs` is optional and is used for associated constants.
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/// This generally happens in late/trans const evaluation.
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pub fn lookup_const_by_id<'a, 'tcx: 'a>(tcx: &'a TyCtxt<'tcx>,
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def_id: DefId,
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substs: Option<subst::Substs<'tcx>>)
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-> Option<(&'tcx Expr, Option<ty::Ty<'tcx>>)> {
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if let Some(node_id) = tcx.map.as_local_node_id(def_id) {
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match tcx.map.find(node_id) {
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None => None,
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Some(ast_map::NodeItem(it)) => match it.node {
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hir::ItemConst(ref ty, ref const_expr) => {
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Some((&const_expr, ast_ty_to_prim_ty(tcx, ty)))
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}
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_ => None
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},
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Some(ast_map::NodeTraitItem(ti)) => match ti.node {
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hir::ConstTraitItem(_, _) => {
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if let Some(substs) = substs {
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// If we have a trait item and the substitutions for it,
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// `resolve_trait_associated_const` will select an impl
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// or the default.
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let trait_id = tcx.trait_of_item(def_id).unwrap();
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resolve_trait_associated_const(tcx, ti, trait_id, substs)
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} else {
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// Technically, without knowing anything about the
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// expression that generates the obligation, we could
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// still return the default if there is one. However,
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// it's safer to return `None` than to return some value
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// that may differ from what you would get from
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// correctly selecting an impl.
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None
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}
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}
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_ => None
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},
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Some(ast_map::NodeImplItem(ii)) => match ii.node {
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hir::ImplItemKind::Const(ref ty, ref expr) => {
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Some((&expr, ast_ty_to_prim_ty(tcx, ty)))
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}
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_ => None
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},
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Some(_) => None
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}
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} else {
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match tcx.extern_const_statics.borrow().get(&def_id) {
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Some(&None) => return None,
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Some(&Some((expr_id, ty))) => {
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return Some((tcx.map.expect_expr(expr_id), ty));
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}
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None => {}
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}
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let mut used_substs = false;
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let expr_ty = match tcx.sess.cstore.maybe_get_item_ast(tcx, def_id) {
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cstore::FoundAst::Found(&InlinedItem::Item(ref item)) => match item.node {
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hir::ItemConst(ref ty, ref const_expr) => {
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Some((&**const_expr, ast_ty_to_prim_ty(tcx, ty)))
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},
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_ => None
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},
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cstore::FoundAst::Found(&InlinedItem::TraitItem(trait_id, ref ti)) => match ti.node {
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hir::ConstTraitItem(_, _) => {
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used_substs = true;
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if let Some(substs) = substs {
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// As mentioned in the comments above for in-crate
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// constants, we only try to find the expression for
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// a trait-associated const if the caller gives us
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// the substitutions for the reference to it.
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resolve_trait_associated_const(tcx, ti, trait_id, substs)
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} else {
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None
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}
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}
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_ => None
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},
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cstore::FoundAst::Found(&InlinedItem::ImplItem(_, ref ii)) => match ii.node {
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hir::ImplItemKind::Const(ref ty, ref expr) => {
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Some((&**expr, ast_ty_to_prim_ty(tcx, ty)))
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},
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_ => None
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},
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_ => None
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};
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// If we used the substitutions, particularly to choose an impl
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// of a trait-associated const, don't cache that, because the next
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// lookup with the same def_id may yield a different result.
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if !used_substs {
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tcx.extern_const_statics
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.borrow_mut()
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.insert(def_id, expr_ty.map(|(e, t)| (e.id, t)));
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}
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expr_ty
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}
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}
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fn inline_const_fn_from_external_crate(tcx: &TyCtxt, def_id: DefId)
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-> Option<ast::NodeId> {
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match tcx.extern_const_fns.borrow().get(&def_id) {
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Some(&ast::DUMMY_NODE_ID) => return None,
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Some(&fn_id) => return Some(fn_id),
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None => {}
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}
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if !tcx.sess.cstore.is_const_fn(def_id) {
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tcx.extern_const_fns.borrow_mut().insert(def_id, ast::DUMMY_NODE_ID);
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return None;
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}
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let fn_id = match tcx.sess.cstore.maybe_get_item_ast(tcx, def_id) {
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cstore::FoundAst::Found(&InlinedItem::Item(ref item)) => Some(item.id),
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cstore::FoundAst::Found(&InlinedItem::ImplItem(_, ref item)) => Some(item.id),
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_ => None
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};
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tcx.extern_const_fns.borrow_mut().insert(def_id,
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fn_id.unwrap_or(ast::DUMMY_NODE_ID));
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fn_id
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}
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pub fn lookup_const_fn_by_id<'tcx>(tcx: &TyCtxt<'tcx>, def_id: DefId)
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-> Option<FnLikeNode<'tcx>>
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{
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let fn_id = if let Some(node_id) = tcx.map.as_local_node_id(def_id) {
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node_id
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} else {
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if let Some(fn_id) = inline_const_fn_from_external_crate(tcx, def_id) {
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fn_id
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} else {
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return None;
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}
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};
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let fn_like = match FnLikeNode::from_node(tcx.map.get(fn_id)) {
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Some(fn_like) => fn_like,
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None => return None
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};
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match fn_like.kind() {
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FnKind::ItemFn(_, _, _, hir::Constness::Const, _, _) => {
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Some(fn_like)
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}
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FnKind::Method(_, m, _) => {
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if m.constness == hir::Constness::Const {
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Some(fn_like)
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} else {
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None
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}
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}
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_ => None
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}
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}
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#[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
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pub enum ConstVal {
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Float(f64),
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Integral(ConstInt),
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Str(InternedString),
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ByteStr(Rc<Vec<u8>>),
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Bool(bool),
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Struct(ast::NodeId),
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Tuple(ast::NodeId),
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Function(DefId),
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Array(ast::NodeId, u64),
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Repeat(ast::NodeId, u64),
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Char(char),
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/// A value that only occurs in case `eval_const_expr` reported an error. You should never
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/// handle this case. Its sole purpose is to allow more errors to be reported instead of
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/// causing a fatal error.
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Dummy,
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}
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impl hash::Hash for ConstVal {
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fn hash<H: hash::Hasher>(&self, state: &mut H) {
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match *self {
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Float(a) => unsafe { transmute::<_,u64>(a) }.hash(state),
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Integral(a) => a.hash(state),
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Str(ref a) => a.hash(state),
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ByteStr(ref a) => a.hash(state),
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Bool(a) => a.hash(state),
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Struct(a) => a.hash(state),
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Tuple(a) => a.hash(state),
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Function(a) => a.hash(state),
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Array(a, n) => { a.hash(state); n.hash(state) },
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Repeat(a, n) => { a.hash(state); n.hash(state) },
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Char(c) => c.hash(state),
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Dummy => ().hash(state),
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}
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}
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}
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/// Note that equality for `ConstVal` means that the it is the same
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/// constant, not that the rust values are equal. In particular, `NaN
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/// == NaN` (at least if it's the same NaN; distinct encodings for NaN
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/// are considering unequal).
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impl PartialEq for ConstVal {
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fn eq(&self, other: &ConstVal) -> bool {
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match (self, other) {
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(&Float(a), &Float(b)) => unsafe{transmute::<_,u64>(a) == transmute::<_,u64>(b)},
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(&Integral(a), &Integral(b)) => a == b,
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(&Str(ref a), &Str(ref b)) => a == b,
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(&ByteStr(ref a), &ByteStr(ref b)) => a == b,
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(&Bool(a), &Bool(b)) => a == b,
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(&Struct(a), &Struct(b)) => a == b,
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(&Tuple(a), &Tuple(b)) => a == b,
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(&Function(a), &Function(b)) => a == b,
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(&Array(a, an), &Array(b, bn)) => (a == b) && (an == bn),
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(&Repeat(a, an), &Repeat(b, bn)) => (a == b) && (an == bn),
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(&Char(a), &Char(b)) => a == b,
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(&Dummy, &Dummy) => true, // FIXME: should this be false?
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_ => false,
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}
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}
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}
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impl Eq for ConstVal { }
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impl ConstVal {
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pub fn description(&self) -> &'static str {
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match *self {
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Float(_) => "float",
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Integral(i) => i.description(),
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Str(_) => "string literal",
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ByteStr(_) => "byte string literal",
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Bool(_) => "boolean",
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Struct(_) => "struct",
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Tuple(_) => "tuple",
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Function(_) => "function definition",
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Array(..) => "array",
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Repeat(..) => "repeat",
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Char(..) => "char",
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Dummy => "dummy value",
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}
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}
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}
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pub fn const_expr_to_pat(tcx: &TyCtxt, expr: &Expr, span: Span) -> P<hir::Pat> {
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let pat = match expr.node {
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hir::ExprTup(ref exprs) =>
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PatKind::Tup(exprs.iter().map(|expr| const_expr_to_pat(tcx, &expr, span)).collect()),
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hir::ExprCall(ref callee, ref args) => {
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let def = *tcx.def_map.borrow().get(&callee.id).unwrap();
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if let Vacant(entry) = tcx.def_map.borrow_mut().entry(expr.id) {
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entry.insert(def);
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}
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let path = match def.full_def() {
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Def::Struct(def_id) => def_to_path(tcx, def_id),
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Def::Variant(_, variant_did) => def_to_path(tcx, variant_did),
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Def::Fn(..) => return P(hir::Pat {
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id: expr.id,
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node: PatKind::Lit(P(expr.clone())),
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span: span,
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}),
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_ => unreachable!()
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};
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let pats = args.iter().map(|expr| const_expr_to_pat(tcx, &expr, span)).collect();
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PatKind::TupleStruct(path, Some(pats))
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}
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hir::ExprStruct(ref path, ref fields, None) => {
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let field_pats = fields.iter().map(|field| codemap::Spanned {
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span: codemap::DUMMY_SP,
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node: hir::FieldPat {
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name: field.name.node,
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pat: const_expr_to_pat(tcx, &field.expr, span),
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is_shorthand: false,
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},
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}).collect();
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PatKind::Struct(path.clone(), field_pats, false)
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}
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hir::ExprVec(ref exprs) => {
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let pats = exprs.iter().map(|expr| const_expr_to_pat(tcx, &expr, span)).collect();
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PatKind::Vec(pats, None, hir::HirVec::new())
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}
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hir::ExprPath(_, ref path) => {
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let opt_def = tcx.def_map.borrow().get(&expr.id).map(|d| d.full_def());
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match opt_def {
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Some(Def::Struct(..)) | Some(Def::Variant(..)) =>
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PatKind::Path(path.clone()),
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Some(Def::Const(def_id)) |
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Some(Def::AssociatedConst(def_id)) => {
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let substs = Some(tcx.node_id_item_substs(expr.id).substs);
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let (expr, _ty) = lookup_const_by_id(tcx, def_id, substs).unwrap();
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return const_expr_to_pat(tcx, expr, span);
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},
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_ => unreachable!(),
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}
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}
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_ => PatKind::Lit(P(expr.clone()))
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};
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P(hir::Pat { id: expr.id, node: pat, span: span })
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}
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pub fn eval_const_expr(tcx: &TyCtxt, e: &Expr) -> ConstVal {
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match eval_const_expr_partial(tcx, e, ExprTypeChecked, None) {
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Ok(r) => r,
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// non-const path still needs to be a fatal error, because enums are funky
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Err(ref s) if s.kind == NonConstPath => tcx.sess.span_fatal(s.span, &s.description()),
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Err(s) => {
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tcx.sess.span_err(s.span, &s.description());
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Dummy
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},
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}
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}
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pub type FnArgMap<'a> = Option<&'a NodeMap<ConstVal>>;
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#[derive(Clone)]
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pub struct ConstEvalErr {
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pub span: Span,
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pub kind: ErrKind,
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}
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|
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#[derive(Clone, PartialEq)]
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pub enum ErrKind {
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CannotCast,
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CannotCastTo(&'static str),
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InvalidOpForInts(hir::BinOp_),
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InvalidOpForBools(hir::BinOp_),
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InvalidOpForFloats(hir::BinOp_),
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InvalidOpForIntUint(hir::BinOp_),
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InvalidOpForUintInt(hir::BinOp_),
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NegateOn(ConstVal),
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NotOn(ConstVal),
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CallOn(ConstVal),
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NegateWithOverflow(i64),
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AddiWithOverflow(i64, i64),
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SubiWithOverflow(i64, i64),
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MuliWithOverflow(i64, i64),
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AdduWithOverflow(u64, u64),
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SubuWithOverflow(u64, u64),
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MuluWithOverflow(u64, u64),
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DivideByZero,
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DivideWithOverflow,
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ModuloByZero,
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ModuloWithOverflow,
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ShiftLeftWithOverflow,
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ShiftRightWithOverflow,
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MissingStructField,
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NonConstPath,
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UnimplementedConstVal(&'static str),
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UnresolvedPath,
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ExpectedConstTuple,
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ExpectedConstStruct,
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TupleIndexOutOfBounds,
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IndexedNonVec,
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IndexNegative,
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IndexNotInt,
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IndexOutOfBounds,
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RepeatCountNotNatural,
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RepeatCountNotInt,
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MiscBinaryOp,
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MiscCatchAll,
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IndexOpFeatureGated,
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Math(ConstMathErr),
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IntermediateUnsignedNegative,
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/// Expected, Got
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TypeMismatch(String, ConstInt),
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BadType(ConstVal),
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}
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impl From<ConstMathErr> for ErrKind {
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fn from(err: ConstMathErr) -> ErrKind {
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Math(err)
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}
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}
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impl ConstEvalErr {
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pub fn description(&self) -> Cow<str> {
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use self::ErrKind::*;
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match self.kind {
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CannotCast => "can't cast this type".into_cow(),
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CannotCastTo(s) => format!("can't cast this type to {}", s).into_cow(),
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InvalidOpForInts(_) => "can't do this op on integrals".into_cow(),
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InvalidOpForBools(_) => "can't do this op on bools".into_cow(),
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InvalidOpForFloats(_) => "can't do this op on floats".into_cow(),
|
|
InvalidOpForIntUint(..) => "can't do this op on an isize and usize".into_cow(),
|
|
InvalidOpForUintInt(..) => "can't do this op on a usize and isize".into_cow(),
|
|
NegateOn(ref const_val) => format!("negate on {}", const_val.description()).into_cow(),
|
|
NotOn(ref const_val) => format!("not on {}", const_val.description()).into_cow(),
|
|
CallOn(ref const_val) => format!("call on {}", const_val.description()).into_cow(),
|
|
|
|
NegateWithOverflow(..) => "attempted to negate with overflow".into_cow(),
|
|
AddiWithOverflow(..) => "attempted to add with overflow".into_cow(),
|
|
SubiWithOverflow(..) => "attempted to sub with overflow".into_cow(),
|
|
MuliWithOverflow(..) => "attempted to mul with overflow".into_cow(),
|
|
AdduWithOverflow(..) => "attempted to add with overflow".into_cow(),
|
|
SubuWithOverflow(..) => "attempted to sub with overflow".into_cow(),
|
|
MuluWithOverflow(..) => "attempted to mul with overflow".into_cow(),
|
|
DivideByZero => "attempted to divide by zero".into_cow(),
|
|
DivideWithOverflow => "attempted to divide with overflow".into_cow(),
|
|
ModuloByZero => "attempted remainder with a divisor of zero".into_cow(),
|
|
ModuloWithOverflow => "attempted remainder with overflow".into_cow(),
|
|
ShiftLeftWithOverflow => "attempted left shift with overflow".into_cow(),
|
|
ShiftRightWithOverflow => "attempted right shift with overflow".into_cow(),
|
|
MissingStructField => "nonexistent struct field".into_cow(),
|
|
NonConstPath => "non-constant path in constant expression".into_cow(),
|
|
UnimplementedConstVal(what) =>
|
|
format!("unimplemented constant expression: {}", what).into_cow(),
|
|
UnresolvedPath => "unresolved path in constant expression".into_cow(),
|
|
ExpectedConstTuple => "expected constant tuple".into_cow(),
|
|
ExpectedConstStruct => "expected constant struct".into_cow(),
|
|
TupleIndexOutOfBounds => "tuple index out of bounds".into_cow(),
|
|
IndexedNonVec => "indexing is only supported for arrays".into_cow(),
|
|
IndexNegative => "indices must be non-negative integers".into_cow(),
|
|
IndexNotInt => "indices must be integers".into_cow(),
|
|
IndexOutOfBounds => "array index out of bounds".into_cow(),
|
|
RepeatCountNotNatural => "repeat count must be a natural number".into_cow(),
|
|
RepeatCountNotInt => "repeat count must be integers".into_cow(),
|
|
|
|
MiscBinaryOp => "bad operands for binary".into_cow(),
|
|
MiscCatchAll => "unsupported constant expr".into_cow(),
|
|
IndexOpFeatureGated => "the index operation on const values is unstable".into_cow(),
|
|
Math(ref err) => err.description().into_cow(),
|
|
|
|
IntermediateUnsignedNegative => "during the computation of an unsigned a negative \
|
|
number was encountered. This is most likely a bug in\
|
|
the constant evaluator".into_cow(),
|
|
|
|
TypeMismatch(ref expected, ref got) => {
|
|
format!("mismatched types: expected `{}`, found `{}`",
|
|
expected, got.description()).into_cow()
|
|
},
|
|
BadType(ref i) => format!("value of wrong type: {:?}", i).into_cow(),
|
|
}
|
|
}
|
|
}
|
|
|
|
pub type EvalResult = Result<ConstVal, ConstEvalErr>;
|
|
pub type CastResult = Result<ConstVal, ErrKind>;
|
|
|
|
// FIXME: Long-term, this enum should go away: trying to evaluate
|
|
// an expression which hasn't been type-checked is a recipe for
|
|
// disaster. That said, it's not clear how to fix ast_ty_to_ty
|
|
// to avoid the ordering issue.
|
|
|
|
/// Hint to determine how to evaluate constant expressions which
|
|
/// might not be type-checked.
|
|
#[derive(Copy, Clone, Debug)]
|
|
pub enum EvalHint<'tcx> {
|
|
/// We have a type-checked expression.
|
|
ExprTypeChecked,
|
|
/// We have an expression which hasn't been type-checked, but we have
|
|
/// an idea of what the type will be because of the context. For example,
|
|
/// the length of an array is always `usize`. (This is referred to as
|
|
/// a hint because it isn't guaranteed to be consistent with what
|
|
/// type-checking would compute.)
|
|
UncheckedExprHint(Ty<'tcx>),
|
|
/// We have an expression which has not yet been type-checked, and
|
|
/// and we have no clue what the type will be.
|
|
UncheckedExprNoHint,
|
|
}
|
|
|
|
impl<'tcx> EvalHint<'tcx> {
|
|
fn erase_hint(&self) -> EvalHint<'tcx> {
|
|
match *self {
|
|
ExprTypeChecked => ExprTypeChecked,
|
|
UncheckedExprHint(_) | UncheckedExprNoHint => UncheckedExprNoHint,
|
|
}
|
|
}
|
|
fn checked_or(&self, ty: Ty<'tcx>) -> EvalHint<'tcx> {
|
|
match *self {
|
|
ExprTypeChecked => ExprTypeChecked,
|
|
_ => UncheckedExprHint(ty),
|
|
}
|
|
}
|
|
}
|
|
|
|
macro_rules! signal {
|
|
($e:expr, $exn:expr) => {
|
|
return Err(ConstEvalErr { span: $e.span, kind: $exn })
|
|
}
|
|
}
|
|
|
|
/// Evaluate a constant expression in a context where the expression isn't
|
|
/// guaranteed to be evaluatable. `ty_hint` is usually ExprTypeChecked,
|
|
/// but a few places need to evaluate constants during type-checking, like
|
|
/// computing the length of an array. (See also the FIXME above EvalHint.)
|
|
pub fn eval_const_expr_partial<'tcx>(tcx: &TyCtxt<'tcx>,
|
|
e: &Expr,
|
|
ty_hint: EvalHint<'tcx>,
|
|
fn_args: FnArgMap) -> EvalResult {
|
|
// Try to compute the type of the expression based on the EvalHint.
|
|
// (See also the definition of EvalHint, and the FIXME above EvalHint.)
|
|
let ety = match ty_hint {
|
|
ExprTypeChecked => {
|
|
// After type-checking, expr_ty is guaranteed to succeed.
|
|
Some(tcx.expr_ty(e))
|
|
}
|
|
UncheckedExprHint(ty) => {
|
|
// Use the type hint; it's not guaranteed to be right, but it's
|
|
// usually good enough.
|
|
Some(ty)
|
|
}
|
|
UncheckedExprNoHint => {
|
|
// This expression might not be type-checked, and we have no hint.
|
|
// Try to query the context for a type anyway; we might get lucky
|
|
// (for example, if the expression was imported from another crate).
|
|
tcx.expr_ty_opt(e)
|
|
}
|
|
};
|
|
let result = match e.node {
|
|
hir::ExprUnary(hir::UnNeg, ref inner) => {
|
|
// unary neg literals already got their sign during creation
|
|
if let hir::ExprLit(ref lit) = inner.node {
|
|
use syntax::ast::*;
|
|
use syntax::ast::LitIntType::*;
|
|
const I8_OVERFLOW: u64 = ::std::i8::MAX as u64 + 1;
|
|
const I16_OVERFLOW: u64 = ::std::i16::MAX as u64 + 1;
|
|
const I32_OVERFLOW: u64 = ::std::i32::MAX as u64 + 1;
|
|
const I64_OVERFLOW: u64 = ::std::i64::MAX as u64 + 1;
|
|
match (&lit.node, ety.map(|t| &t.sty)) {
|
|
(&LitKind::Int(I8_OVERFLOW, Unsuffixed), Some(&ty::TyInt(IntTy::I8))) |
|
|
(&LitKind::Int(I8_OVERFLOW, Signed(IntTy::I8)), _) => {
|
|
return Ok(Integral(I8(::std::i8::MIN)))
|
|
},
|
|
(&LitKind::Int(I16_OVERFLOW, Unsuffixed), Some(&ty::TyInt(IntTy::I16))) |
|
|
(&LitKind::Int(I16_OVERFLOW, Signed(IntTy::I16)), _) => {
|
|
return Ok(Integral(I16(::std::i16::MIN)))
|
|
},
|
|
(&LitKind::Int(I32_OVERFLOW, Unsuffixed), Some(&ty::TyInt(IntTy::I32))) |
|
|
(&LitKind::Int(I32_OVERFLOW, Signed(IntTy::I32)), _) => {
|
|
return Ok(Integral(I32(::std::i32::MIN)))
|
|
},
|
|
(&LitKind::Int(I64_OVERFLOW, Unsuffixed), Some(&ty::TyInt(IntTy::I64))) |
|
|
(&LitKind::Int(I64_OVERFLOW, Signed(IntTy::I64)), _) => {
|
|
return Ok(Integral(I64(::std::i64::MIN)))
|
|
},
|
|
(&LitKind::Int(n, Unsuffixed), Some(&ty::TyInt(IntTy::Is))) |
|
|
(&LitKind::Int(n, Signed(IntTy::Is)), _) => {
|
|
match tcx.sess.target.int_type {
|
|
IntTy::I32 => if n == I32_OVERFLOW {
|
|
return Ok(Integral(Isize(Is32(::std::i32::MIN))));
|
|
},
|
|
IntTy::I64 => if n == I64_OVERFLOW {
|
|
return Ok(Integral(Isize(Is64(::std::i64::MIN))));
|
|
},
|
|
_ => unreachable!(),
|
|
}
|
|
},
|
|
_ => {},
|
|
}
|
|
}
|
|
match try!(eval_const_expr_partial(tcx, &inner, ty_hint, fn_args)) {
|
|
Float(f) => Float(-f),
|
|
Integral(i) => Integral(math!(e, -i)),
|
|
const_val => signal!(e, NegateOn(const_val)),
|
|
}
|
|
}
|
|
hir::ExprUnary(hir::UnNot, ref inner) => {
|
|
match try!(eval_const_expr_partial(tcx, &inner, ty_hint, fn_args)) {
|
|
Integral(i) => Integral(math!(e, !i)),
|
|
Bool(b) => Bool(!b),
|
|
const_val => signal!(e, NotOn(const_val)),
|
|
}
|
|
}
|
|
hir::ExprBinary(op, ref a, ref b) => {
|
|
let b_ty = match op.node {
|
|
hir::BiShl | hir::BiShr => ty_hint.erase_hint(),
|
|
_ => ty_hint
|
|
};
|
|
// technically, if we don't have type hints, but integral eval
|
|
// gives us a type through a type-suffix, cast or const def type
|
|
// we need to re-eval the other value of the BinOp if it was
|
|
// not inferred
|
|
match (try!(eval_const_expr_partial(tcx, &a, ty_hint, fn_args)),
|
|
try!(eval_const_expr_partial(tcx, &b, b_ty, fn_args))) {
|
|
(Float(a), Float(b)) => {
|
|
match op.node {
|
|
hir::BiAdd => Float(a + b),
|
|
hir::BiSub => Float(a - b),
|
|
hir::BiMul => Float(a * b),
|
|
hir::BiDiv => Float(a / b),
|
|
hir::BiRem => Float(a % b),
|
|
hir::BiEq => Bool(a == b),
|
|
hir::BiLt => Bool(a < b),
|
|
hir::BiLe => Bool(a <= b),
|
|
hir::BiNe => Bool(a != b),
|
|
hir::BiGe => Bool(a >= b),
|
|
hir::BiGt => Bool(a > b),
|
|
_ => signal!(e, InvalidOpForFloats(op.node)),
|
|
}
|
|
}
|
|
(Integral(a), Integral(b)) => {
|
|
use std::cmp::Ordering::*;
|
|
match op.node {
|
|
hir::BiAdd => Integral(math!(e, a + b)),
|
|
hir::BiSub => Integral(math!(e, a - b)),
|
|
hir::BiMul => Integral(math!(e, a * b)),
|
|
hir::BiDiv => Integral(math!(e, a / b)),
|
|
hir::BiRem => Integral(math!(e, a % b)),
|
|
hir::BiBitAnd => Integral(math!(e, a & b)),
|
|
hir::BiBitOr => Integral(math!(e, a | b)),
|
|
hir::BiBitXor => Integral(math!(e, a ^ b)),
|
|
hir::BiShl => Integral(math!(e, a << b)),
|
|
hir::BiShr => Integral(math!(e, a >> b)),
|
|
hir::BiEq => Bool(math!(e, a.try_cmp(b)) == Equal),
|
|
hir::BiLt => Bool(math!(e, a.try_cmp(b)) == Less),
|
|
hir::BiLe => Bool(math!(e, a.try_cmp(b)) != Greater),
|
|
hir::BiNe => Bool(math!(e, a.try_cmp(b)) != Equal),
|
|
hir::BiGe => Bool(math!(e, a.try_cmp(b)) != Less),
|
|
hir::BiGt => Bool(math!(e, a.try_cmp(b)) == Greater),
|
|
_ => signal!(e, InvalidOpForInts(op.node)),
|
|
}
|
|
}
|
|
(Bool(a), Bool(b)) => {
|
|
Bool(match op.node {
|
|
hir::BiAnd => a && b,
|
|
hir::BiOr => a || b,
|
|
hir::BiBitXor => a ^ b,
|
|
hir::BiBitAnd => a & b,
|
|
hir::BiBitOr => a | b,
|
|
hir::BiEq => a == b,
|
|
hir::BiNe => a != b,
|
|
_ => signal!(e, InvalidOpForBools(op.node)),
|
|
})
|
|
}
|
|
|
|
_ => signal!(e, MiscBinaryOp),
|
|
}
|
|
}
|
|
hir::ExprCast(ref base, ref target_ty) => {
|
|
let ety = ast_ty_to_prim_ty(tcx, &target_ty).or_else(|| ety)
|
|
.unwrap_or_else(|| {
|
|
tcx.sess.span_fatal(target_ty.span,
|
|
"target type not found for const cast")
|
|
});
|
|
|
|
let base_hint = if let ExprTypeChecked = ty_hint {
|
|
ExprTypeChecked
|
|
} else {
|
|
match tcx.expr_ty_opt(&base) {
|
|
Some(t) => UncheckedExprHint(t),
|
|
None => ty_hint
|
|
}
|
|
};
|
|
|
|
let val = match eval_const_expr_partial(tcx, &base, base_hint, fn_args) {
|
|
Ok(val) => val,
|
|
Err(ConstEvalErr { kind: TypeMismatch(_, val), .. }) => {
|
|
// Something like `5i8 as usize` doesn't need a type hint for the base
|
|
// instead take the type hint from the inner value
|
|
let hint = match val.int_type() {
|
|
Some(IntType::UnsignedInt(ty)) => ty_hint.checked_or(tcx.mk_mach_uint(ty)),
|
|
Some(IntType::SignedInt(ty)) => ty_hint.checked_or(tcx.mk_mach_int(ty)),
|
|
// we had a type hint, so we can't have an unknown type
|
|
None => unreachable!(),
|
|
};
|
|
try!(eval_const_expr_partial(tcx, &base, hint, fn_args))
|
|
},
|
|
Err(e) => return Err(e),
|
|
};
|
|
match cast_const(tcx, val, ety) {
|
|
Ok(val) => val,
|
|
Err(kind) => return Err(ConstEvalErr { span: e.span, kind: kind }),
|
|
}
|
|
}
|
|
hir::ExprPath(..) => {
|
|
let opt_def = if let Some(def) = tcx.def_map.borrow().get(&e.id) {
|
|
// After type-checking, def_map contains definition of the
|
|
// item referred to by the path. During type-checking, it
|
|
// can contain the raw output of path resolution, which
|
|
// might be a partially resolved path.
|
|
// FIXME: There's probably a better way to make sure we don't
|
|
// panic here.
|
|
if def.depth != 0 {
|
|
signal!(e, UnresolvedPath);
|
|
}
|
|
def.full_def()
|
|
} else {
|
|
signal!(e, NonConstPath);
|
|
};
|
|
match opt_def {
|
|
Def::Const(def_id) |
|
|
Def::AssociatedConst(def_id) => {
|
|
let substs = if let ExprTypeChecked = ty_hint {
|
|
Some(tcx.node_id_item_substs(e.id).substs)
|
|
} else {
|
|
None
|
|
};
|
|
if let Some((e, ty)) = lookup_const_by_id(tcx, def_id, substs) {
|
|
let item_hint = match ty {
|
|
Some(ty) => ty_hint.checked_or(ty),
|
|
None => ty_hint,
|
|
};
|
|
try!(eval_const_expr_partial(tcx, e, item_hint, None))
|
|
} else {
|
|
signal!(e, NonConstPath);
|
|
}
|
|
},
|
|
Def::Variant(enum_def, variant_def) => {
|
|
if let Some(const_expr) = lookup_variant_by_id(tcx, enum_def, variant_def) {
|
|
try!(eval_const_expr_partial(tcx, const_expr, ty_hint, None))
|
|
} else {
|
|
signal!(e, NonConstPath);
|
|
}
|
|
}
|
|
Def::Struct(..) => {
|
|
ConstVal::Struct(e.id)
|
|
}
|
|
Def::Local(_, id) => {
|
|
debug!("Def::Local({:?}): {:?}", id, fn_args);
|
|
if let Some(val) = fn_args.and_then(|args| args.get(&id)) {
|
|
val.clone()
|
|
} else {
|
|
signal!(e, NonConstPath);
|
|
}
|
|
},
|
|
Def::Method(id) | Def::Fn(id) => Function(id),
|
|
_ => signal!(e, NonConstPath),
|
|
}
|
|
}
|
|
hir::ExprCall(ref callee, ref args) => {
|
|
let sub_ty_hint = ty_hint.erase_hint();
|
|
let callee_val = try!(eval_const_expr_partial(tcx, callee, sub_ty_hint, fn_args));
|
|
let did = match callee_val {
|
|
Function(did) => did,
|
|
callee => signal!(e, CallOn(callee)),
|
|
};
|
|
let (decl, result) = if let Some(fn_like) = lookup_const_fn_by_id(tcx, did) {
|
|
(fn_like.decl(), &fn_like.body().expr)
|
|
} else {
|
|
signal!(e, NonConstPath)
|
|
};
|
|
let result = result.as_ref().expect("const fn has no result expression");
|
|
assert_eq!(decl.inputs.len(), args.len());
|
|
|
|
let mut call_args = NodeMap();
|
|
for (arg, arg_expr) in decl.inputs.iter().zip(args.iter()) {
|
|
let arg_hint = ty_hint.erase_hint();
|
|
let arg_val = try!(eval_const_expr_partial(
|
|
tcx,
|
|
arg_expr,
|
|
arg_hint,
|
|
fn_args
|
|
));
|
|
debug!("const call arg: {:?}", arg);
|
|
let old = call_args.insert(arg.pat.id, arg_val);
|
|
assert!(old.is_none());
|
|
}
|
|
debug!("const call({:?})", call_args);
|
|
try!(eval_const_expr_partial(tcx, &result, ty_hint, Some(&call_args)))
|
|
},
|
|
hir::ExprLit(ref lit) => try!(lit_to_const(&lit.node, tcx, ety, lit.span)),
|
|
hir::ExprBlock(ref block) => {
|
|
match block.expr {
|
|
Some(ref expr) => try!(eval_const_expr_partial(tcx, &expr, ty_hint, fn_args)),
|
|
None => unreachable!(),
|
|
}
|
|
}
|
|
hir::ExprType(ref e, _) => try!(eval_const_expr_partial(tcx, &e, ty_hint, fn_args)),
|
|
hir::ExprTup(_) => Tuple(e.id),
|
|
hir::ExprStruct(..) => Struct(e.id),
|
|
hir::ExprIndex(ref arr, ref idx) => {
|
|
if !tcx.sess.features.borrow().const_indexing {
|
|
signal!(e, IndexOpFeatureGated);
|
|
}
|
|
let arr_hint = ty_hint.erase_hint();
|
|
let arr = try!(eval_const_expr_partial(tcx, arr, arr_hint, fn_args));
|
|
let idx_hint = ty_hint.checked_or(tcx.types.usize);
|
|
let idx = match try!(eval_const_expr_partial(tcx, idx, idx_hint, fn_args)) {
|
|
Integral(Usize(i)) => i.as_u64(tcx.sess.target.uint_type),
|
|
Integral(_) => unreachable!(),
|
|
_ => signal!(idx, IndexNotInt),
|
|
};
|
|
assert_eq!(idx as usize as u64, idx);
|
|
match arr {
|
|
Array(_, n) if idx >= n => signal!(e, IndexOutOfBounds),
|
|
Array(v, n) => if let hir::ExprVec(ref v) = tcx.map.expect_expr(v).node {
|
|
assert_eq!(n as usize as u64, n);
|
|
try!(eval_const_expr_partial(tcx, &v[idx as usize], ty_hint, fn_args))
|
|
} else {
|
|
unreachable!()
|
|
},
|
|
|
|
Repeat(_, n) if idx >= n => signal!(e, IndexOutOfBounds),
|
|
Repeat(elem, _) => try!(eval_const_expr_partial(
|
|
tcx,
|
|
&tcx.map.expect_expr(elem),
|
|
ty_hint,
|
|
fn_args,
|
|
)),
|
|
|
|
ByteStr(ref data) if idx >= data.len() as u64 => signal!(e, IndexOutOfBounds),
|
|
ByteStr(data) => {
|
|
Integral(U8(data[idx as usize]))
|
|
},
|
|
|
|
Str(ref s) if idx as usize >= s.len() => signal!(e, IndexOutOfBounds),
|
|
Str(_) => unimplemented!(), // FIXME: return a const char
|
|
_ => signal!(e, IndexedNonVec),
|
|
}
|
|
}
|
|
hir::ExprVec(ref v) => Array(e.id, v.len() as u64),
|
|
hir::ExprRepeat(_, ref n) => {
|
|
let len_hint = ty_hint.checked_or(tcx.types.usize);
|
|
Repeat(
|
|
e.id,
|
|
match try!(eval_const_expr_partial(tcx, &n, len_hint, fn_args)) {
|
|
Integral(Usize(i)) => i.as_u64(tcx.sess.target.uint_type),
|
|
Integral(_) => signal!(e, RepeatCountNotNatural),
|
|
_ => signal!(e, RepeatCountNotInt),
|
|
},
|
|
)
|
|
},
|
|
hir::ExprTupField(ref base, index) => {
|
|
let base_hint = ty_hint.erase_hint();
|
|
let c = try!(eval_const_expr_partial(tcx, base, base_hint, fn_args));
|
|
if let Tuple(tup_id) = c {
|
|
if let hir::ExprTup(ref fields) = tcx.map.expect_expr(tup_id).node {
|
|
if index.node < fields.len() {
|
|
try!(eval_const_expr_partial(tcx, &fields[index.node], ty_hint, fn_args))
|
|
} else {
|
|
signal!(e, TupleIndexOutOfBounds);
|
|
}
|
|
} else {
|
|
unreachable!()
|
|
}
|
|
} else {
|
|
signal!(base, ExpectedConstTuple);
|
|
}
|
|
}
|
|
hir::ExprField(ref base, field_name) => {
|
|
let base_hint = ty_hint.erase_hint();
|
|
// Get the base expression if it is a struct and it is constant
|
|
let c = try!(eval_const_expr_partial(tcx, base, base_hint, fn_args));
|
|
if let Struct(struct_id) = c {
|
|
if let hir::ExprStruct(_, ref fields, _) = tcx.map.expect_expr(struct_id).node {
|
|
// Check that the given field exists and evaluate it
|
|
// if the idents are compared run-pass/issue-19244 fails
|
|
if let Some(f) = fields.iter().find(|f| f.name.node
|
|
== field_name.node) {
|
|
try!(eval_const_expr_partial(tcx, &f.expr, ty_hint, fn_args))
|
|
} else {
|
|
signal!(e, MissingStructField);
|
|
}
|
|
} else {
|
|
unreachable!()
|
|
}
|
|
} else {
|
|
signal!(base, ExpectedConstStruct);
|
|
}
|
|
}
|
|
_ => signal!(e, MiscCatchAll)
|
|
};
|
|
|
|
match (ety.map(|t| &t.sty), result) {
|
|
(Some(ref ty_hint), Integral(i)) => Ok(Integral(try!(infer(i, tcx, ty_hint, e.span)))),
|
|
(_, result) => Ok(result),
|
|
}
|
|
}
|
|
|
|
fn infer<'tcx>(
|
|
i: ConstInt,
|
|
tcx: &TyCtxt<'tcx>,
|
|
ty_hint: &ty::TypeVariants<'tcx>,
|
|
span: Span
|
|
) -> Result<ConstInt, ConstEvalErr> {
|
|
use syntax::ast::*;
|
|
|
|
let err = |e| ConstEvalErr {
|
|
span: span,
|
|
kind: e,
|
|
};
|
|
|
|
match (ty_hint, i) {
|
|
(&ty::TyInt(IntTy::I8), result @ I8(_)) => Ok(result),
|
|
(&ty::TyInt(IntTy::I16), result @ I16(_)) => Ok(result),
|
|
(&ty::TyInt(IntTy::I32), result @ I32(_)) => Ok(result),
|
|
(&ty::TyInt(IntTy::I64), result @ I64(_)) => Ok(result),
|
|
(&ty::TyInt(IntTy::Is), result @ Isize(_)) => Ok(result),
|
|
|
|
(&ty::TyUint(UintTy::U8), result @ U8(_)) => Ok(result),
|
|
(&ty::TyUint(UintTy::U16), result @ U16(_)) => Ok(result),
|
|
(&ty::TyUint(UintTy::U32), result @ U32(_)) => Ok(result),
|
|
(&ty::TyUint(UintTy::U64), result @ U64(_)) => Ok(result),
|
|
(&ty::TyUint(UintTy::Us), result @ Usize(_)) => Ok(result),
|
|
|
|
(&ty::TyInt(IntTy::I8), Infer(i)) => Ok(I8(i as i64 as i8)),
|
|
(&ty::TyInt(IntTy::I16), Infer(i)) => Ok(I16(i as i64 as i16)),
|
|
(&ty::TyInt(IntTy::I32), Infer(i)) => Ok(I32(i as i64 as i32)),
|
|
(&ty::TyInt(IntTy::I64), Infer(i)) => Ok(I64(i as i64)),
|
|
(&ty::TyInt(IntTy::Is), Infer(i)) => {
|
|
match ConstIsize::new(i as i64, tcx.sess.target.int_type) {
|
|
Ok(val) => Ok(Isize(val)),
|
|
Err(_) => Ok(Isize(ConstIsize::Is32(i as i64 as i32))),
|
|
}
|
|
},
|
|
|
|
(&ty::TyInt(IntTy::I8), InferSigned(i)) => Ok(I8(i as i8)),
|
|
(&ty::TyInt(IntTy::I16), InferSigned(i)) => Ok(I16(i as i16)),
|
|
(&ty::TyInt(IntTy::I32), InferSigned(i)) => Ok(I32(i as i32)),
|
|
(&ty::TyInt(IntTy::I64), InferSigned(i)) => Ok(I64(i)),
|
|
(&ty::TyInt(IntTy::Is), InferSigned(i)) => {
|
|
match ConstIsize::new(i, tcx.sess.target.int_type) {
|
|
Ok(val) => Ok(Isize(val)),
|
|
Err(_) => Ok(Isize(ConstIsize::Is32(i as i32))),
|
|
}
|
|
},
|
|
|
|
(&ty::TyUint(UintTy::U8), Infer(i)) => Ok(U8(i as u8)),
|
|
(&ty::TyUint(UintTy::U16), Infer(i)) => Ok(U16(i as u16)),
|
|
(&ty::TyUint(UintTy::U32), Infer(i)) => Ok(U32(i as u32)),
|
|
(&ty::TyUint(UintTy::U64), Infer(i)) => Ok(U64(i)),
|
|
(&ty::TyUint(UintTy::Us), Infer(i)) => {
|
|
match ConstUsize::new(i, tcx.sess.target.uint_type) {
|
|
Ok(val) => Ok(Usize(val)),
|
|
Err(_) => Ok(Usize(ConstUsize::Us32(i as u32))),
|
|
}
|
|
},
|
|
(&ty::TyUint(_), InferSigned(_)) => Err(err(IntermediateUnsignedNegative)),
|
|
|
|
(&ty::TyInt(ity), i) => Err(err(TypeMismatch(ity.to_string(), i))),
|
|
(&ty::TyUint(ity), i) => Err(err(TypeMismatch(ity.to_string(), i))),
|
|
|
|
(&ty::TyEnum(ref adt, _), i) => {
|
|
let hints = tcx.lookup_repr_hints(adt.did);
|
|
let int_ty = tcx.enum_repr_type(hints.iter().next());
|
|
infer(i, tcx, &int_ty.to_ty(tcx).sty, span)
|
|
},
|
|
(_, i) => Err(err(BadType(ConstVal::Integral(i)))),
|
|
}
|
|
}
|
|
|
|
fn resolve_trait_associated_const<'a, 'tcx: 'a>(tcx: &'a TyCtxt<'tcx>,
|
|
ti: &'tcx hir::TraitItem,
|
|
trait_id: DefId,
|
|
rcvr_substs: subst::Substs<'tcx>)
|
|
-> Option<(&'tcx Expr, Option<ty::Ty<'tcx>>)>
|
|
{
|
|
let trait_ref = ty::Binder(
|
|
rcvr_substs.erase_regions().to_trait_ref(tcx, trait_id)
|
|
);
|
|
debug!("resolve_trait_associated_const: trait_ref={:?}",
|
|
trait_ref);
|
|
|
|
tcx.populate_implementations_for_trait_if_necessary(trait_ref.def_id());
|
|
let infcx = infer::new_infer_ctxt(tcx, &tcx.tables, None, ProjectionMode::AnyFinal);
|
|
|
|
let mut selcx = traits::SelectionContext::new(&infcx);
|
|
let obligation = traits::Obligation::new(traits::ObligationCause::dummy(),
|
|
trait_ref.to_poly_trait_predicate());
|
|
let selection = match selcx.select(&obligation) {
|
|
Ok(Some(vtable)) => vtable,
|
|
// Still ambiguous, so give up and let the caller decide whether this
|
|
// expression is really needed yet. Some associated constant values
|
|
// can't be evaluated until monomorphization is done in trans.
|
|
Ok(None) => {
|
|
return None
|
|
}
|
|
Err(_) => {
|
|
return None
|
|
}
|
|
};
|
|
|
|
// NOTE: this code does not currently account for specialization, but when
|
|
// it does so, it should hook into the ProjectionMode to determine when the
|
|
// constant should resolve; this will also require plumbing through to this
|
|
// function whether we are in "trans mode" to pick the right ProjectionMode
|
|
// when constructing the inference context above.
|
|
match selection {
|
|
traits::VtableImpl(ref impl_data) => {
|
|
match tcx.associated_consts(impl_data.impl_def_id)
|
|
.iter().find(|ic| ic.name == ti.name) {
|
|
Some(ic) => lookup_const_by_id(tcx, ic.def_id, None),
|
|
None => match ti.node {
|
|
hir::ConstTraitItem(ref ty, Some(ref expr)) => {
|
|
Some((&*expr, ast_ty_to_prim_ty(tcx, ty)))
|
|
},
|
|
_ => None,
|
|
},
|
|
}
|
|
}
|
|
_ => {
|
|
tcx.sess.span_bug(
|
|
ti.span,
|
|
"resolve_trait_associated_const: unexpected vtable type")
|
|
}
|
|
}
|
|
}
|
|
|
|
fn cast_const_int<'tcx>(tcx: &TyCtxt<'tcx>, val: ConstInt, ty: ty::Ty) -> CastResult {
|
|
let v = val.to_u64_unchecked();
|
|
match ty.sty {
|
|
ty::TyBool if v == 0 => Ok(Bool(false)),
|
|
ty::TyBool if v == 1 => Ok(Bool(true)),
|
|
ty::TyInt(ast::IntTy::I8) => Ok(Integral(I8(v as i64 as i8))),
|
|
ty::TyInt(ast::IntTy::I16) => Ok(Integral(I16(v as i64 as i16))),
|
|
ty::TyInt(ast::IntTy::I32) => Ok(Integral(I32(v as i64 as i32))),
|
|
ty::TyInt(ast::IntTy::I64) => Ok(Integral(I64(v as i64))),
|
|
ty::TyInt(ast::IntTy::Is) => {
|
|
match ConstIsize::new(v as i64, tcx.sess.target.int_type) {
|
|
Ok(val) => Ok(Integral(Isize(val))),
|
|
Err(_) => Ok(Integral(Isize(ConstIsize::Is32(v as i64 as i32)))),
|
|
}
|
|
},
|
|
ty::TyUint(ast::UintTy::U8) => Ok(Integral(U8(v as u8))),
|
|
ty::TyUint(ast::UintTy::U16) => Ok(Integral(U16(v as u16))),
|
|
ty::TyUint(ast::UintTy::U32) => Ok(Integral(U32(v as u32))),
|
|
ty::TyUint(ast::UintTy::U64) => Ok(Integral(U64(v))),
|
|
ty::TyUint(ast::UintTy::Us) => {
|
|
match ConstUsize::new(v, tcx.sess.target.uint_type) {
|
|
Ok(val) => Ok(Integral(Usize(val))),
|
|
Err(_) => Ok(Integral(Usize(ConstUsize::Us32(v as u32)))),
|
|
}
|
|
},
|
|
ty::TyFloat(ast::FloatTy::F64) if val.is_negative() => {
|
|
// FIXME: this could probably be prettier
|
|
// there's no easy way to turn an `Infer` into a f64
|
|
let val = try!((-val).map_err(Math));
|
|
let val = val.to_u64().unwrap() as f64;
|
|
let val = -val;
|
|
Ok(Float(val))
|
|
},
|
|
ty::TyFloat(ast::FloatTy::F64) => Ok(Float(val.to_u64().unwrap() as f64)),
|
|
ty::TyFloat(ast::FloatTy::F32) if val.is_negative() => {
|
|
let val = try!((-val).map_err(Math));
|
|
let val = val.to_u64().unwrap() as f32;
|
|
let val = -val;
|
|
Ok(Float(val as f64))
|
|
},
|
|
ty::TyFloat(ast::FloatTy::F32) => Ok(Float(val.to_u64().unwrap() as f32 as f64)),
|
|
_ => Err(CannotCast),
|
|
}
|
|
}
|
|
|
|
fn cast_const_float<'tcx>(tcx: &TyCtxt<'tcx>, f: f64, ty: ty::Ty) -> CastResult {
|
|
match ty.sty {
|
|
ty::TyInt(_) if f >= 0.0 => cast_const_int(tcx, Infer(f as u64), ty),
|
|
ty::TyInt(_) => cast_const_int(tcx, InferSigned(f as i64), ty),
|
|
ty::TyUint(_) if f >= 0.0 => cast_const_int(tcx, Infer(f as u64), ty),
|
|
ty::TyFloat(ast::FloatTy::F64) => Ok(Float(f)),
|
|
ty::TyFloat(ast::FloatTy::F32) => Ok(Float(f as f32 as f64)),
|
|
_ => Err(CannotCast),
|
|
}
|
|
}
|
|
|
|
fn cast_const<'tcx>(tcx: &TyCtxt<'tcx>, val: ConstVal, ty: ty::Ty) -> CastResult {
|
|
match val {
|
|
Integral(i) => cast_const_int(tcx, i, ty),
|
|
Bool(b) => cast_const_int(tcx, Infer(b as u64), ty),
|
|
Float(f) => cast_const_float(tcx, f, ty),
|
|
Char(c) => cast_const_int(tcx, Infer(c as u64), ty),
|
|
_ => Err(CannotCast),
|
|
}
|
|
}
|
|
|
|
fn lit_to_const<'tcx>(lit: &ast::LitKind,
|
|
tcx: &TyCtxt<'tcx>,
|
|
ty_hint: Option<Ty<'tcx>>,
|
|
span: Span,
|
|
) -> Result<ConstVal, ConstEvalErr> {
|
|
use syntax::ast::*;
|
|
use syntax::ast::LitIntType::*;
|
|
match *lit {
|
|
LitKind::Str(ref s, _) => Ok(Str((*s).clone())),
|
|
LitKind::ByteStr(ref data) => Ok(ByteStr(data.clone())),
|
|
LitKind::Byte(n) => Ok(Integral(U8(n))),
|
|
LitKind::Int(n, Signed(ity)) => {
|
|
infer(InferSigned(n as i64), tcx, &ty::TyInt(ity), span).map(Integral)
|
|
},
|
|
|
|
LitKind::Int(n, Unsuffixed) => {
|
|
match ty_hint.map(|t| &t.sty) {
|
|
Some(&ty::TyInt(ity)) => {
|
|
infer(InferSigned(n as i64), tcx, &ty::TyInt(ity), span).map(Integral)
|
|
},
|
|
Some(&ty::TyUint(uty)) => {
|
|
infer(Infer(n), tcx, &ty::TyUint(uty), span).map(Integral)
|
|
},
|
|
None => Ok(Integral(Infer(n))),
|
|
Some(&ty::TyEnum(ref adt, _)) => {
|
|
let hints = tcx.lookup_repr_hints(adt.did);
|
|
let int_ty = tcx.enum_repr_type(hints.iter().next());
|
|
infer(Infer(n), tcx, &int_ty.to_ty(tcx).sty, span).map(Integral)
|
|
},
|
|
Some(ty_hint) => panic!("bad ty_hint: {:?}, {:?}", ty_hint, lit),
|
|
}
|
|
},
|
|
LitKind::Int(n, Unsigned(ity)) => {
|
|
infer(Infer(n), tcx, &ty::TyUint(ity), span).map(Integral)
|
|
},
|
|
|
|
LitKind::Float(ref n, _) |
|
|
LitKind::FloatUnsuffixed(ref n) => {
|
|
if let Ok(x) = n.parse::<f64>() {
|
|
Ok(Float(x))
|
|
} else {
|
|
// FIXME(#31407) this is only necessary because float parsing is buggy
|
|
tcx.sess.span_bug(span, "could not evaluate float literal (see issue #31407)");
|
|
}
|
|
}
|
|
LitKind::Bool(b) => Ok(Bool(b)),
|
|
LitKind::Char(c) => Ok(Char(c)),
|
|
}
|
|
}
|
|
|
|
pub fn compare_const_vals(a: &ConstVal, b: &ConstVal) -> Option<Ordering> {
|
|
match (a, b) {
|
|
(&Integral(a), &Integral(b)) => a.try_cmp(b).ok(),
|
|
(&Float(a), &Float(b)) => {
|
|
// This is pretty bad but it is the existing behavior.
|
|
Some(if a == b {
|
|
Ordering::Equal
|
|
} else if a < b {
|
|
Ordering::Less
|
|
} else {
|
|
Ordering::Greater
|
|
})
|
|
}
|
|
(&Str(ref a), &Str(ref b)) => Some(a.cmp(b)),
|
|
(&Bool(a), &Bool(b)) => Some(a.cmp(&b)),
|
|
(&ByteStr(ref a), &ByteStr(ref b)) => Some(a.cmp(b)),
|
|
(&Char(a), &Char(ref b)) => Some(a.cmp(b)),
|
|
_ => None,
|
|
}
|
|
}
|
|
|
|
pub fn compare_lit_exprs<'tcx>(tcx: &TyCtxt<'tcx>,
|
|
a: &Expr,
|
|
b: &Expr) -> Option<Ordering> {
|
|
let a = match eval_const_expr_partial(tcx, a, ExprTypeChecked, None) {
|
|
Ok(a) => a,
|
|
Err(e) => {
|
|
tcx.sess.span_err(a.span, &e.description());
|
|
return None;
|
|
}
|
|
};
|
|
let b = match eval_const_expr_partial(tcx, b, ExprTypeChecked, None) {
|
|
Ok(b) => b,
|
|
Err(e) => {
|
|
tcx.sess.span_err(b.span, &e.description());
|
|
return None;
|
|
}
|
|
};
|
|
compare_const_vals(&a, &b)
|
|
}
|