724 lines
28 KiB
Rust
724 lines
28 KiB
Rust
// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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#![allow(non_camel_case_types)]
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#![allow(unsigned_negation)]
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pub use self::const_val::*;
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use metadata::csearch;
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use middle::{astencode, def};
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use middle::pat_util::def_to_path;
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use middle::ty::{self, Ty};
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use middle::astconv_util::ast_ty_to_prim_ty;
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use syntax::ast::{self, Expr};
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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::{ast_map, ast_util, codemap};
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use std::borrow::{Cow, IntoCow};
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use std::num::wrapping::OverflowingOps;
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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::{i8, i16, i32, i64};
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use std::rc::Rc;
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fn lookup_const<'a>(tcx: &'a ty::ctxt, e: &Expr) -> Option<&'a Expr> {
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let opt_def = tcx.def_map.borrow().get(&e.id).map(|d| d.full_def());
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match opt_def {
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Some(def::DefConst(def_id)) => {
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lookup_const_by_id(tcx, def_id)
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}
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Some(def::DefVariant(enum_def, variant_def, _)) => {
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lookup_variant_by_id(tcx, enum_def, variant_def)
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}
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_ => None
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}
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}
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fn lookup_variant_by_id<'a>(tcx: &'a ty::ctxt,
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enum_def: ast::DefId,
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variant_def: ast::DefId)
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-> Option<&'a Expr> {
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fn variant_expr<'a>(variants: &'a [P<ast::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.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 ast_util::is_local(enum_def) {
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match tcx.map.find(enum_def.node) {
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None => None,
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Some(ast_map::NodeItem(it)) => match it.node {
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ast::ItemEnum(ast::EnumDef { ref variants }, _) => {
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variant_expr(&variants[..], variant_def.node)
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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_variants.borrow().get(&variant_def) {
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Some(&ast::DUMMY_NODE_ID) => return None,
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Some(&expr_id) => {
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return Some(tcx.map.expect_expr(expr_id));
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}
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None => {}
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}
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let expr_id = match csearch::maybe_get_item_ast(tcx, enum_def,
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Box::new(|a, b, c, d| astencode::decode_inlined_item(a, b, c, d))) {
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csearch::FoundAst::Found(&ast::IIItem(ref item)) => match item.node {
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ast::ItemEnum(ast::EnumDef { ref variants }, _) => {
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// NOTE this doesn't do the right thing, it compares inlined
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// NodeId's to the original variant_def's NodeId, but they
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// come from different crates, so they will likely never match.
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variant_expr(&variants[..], variant_def.node).map(|e| e.id)
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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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tcx.extern_const_variants.borrow_mut().insert(variant_def,
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expr_id.unwrap_or(ast::DUMMY_NODE_ID));
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expr_id.map(|id| tcx.map.expect_expr(id))
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}
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}
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pub fn lookup_const_by_id<'a>(tcx: &'a ty::ctxt, def_id: ast::DefId)
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-> Option<&'a Expr> {
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if ast_util::is_local(def_id) {
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match tcx.map.find(def_id.node) {
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None => None,
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Some(ast_map::NodeItem(it)) => match it.node {
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ast::ItemConst(_, ref const_expr) => {
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Some(&**const_expr)
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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(&ast::DUMMY_NODE_ID) => return None,
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Some(&expr_id) => {
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return Some(tcx.map.expect_expr(expr_id));
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}
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None => {}
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}
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let expr_id = match csearch::maybe_get_item_ast(tcx, def_id,
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Box::new(|a, b, c, d| astencode::decode_inlined_item(a, b, c, d))) {
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csearch::FoundAst::Found(&ast::IIItem(ref item)) => match item.node {
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ast::ItemConst(_, ref const_expr) => Some(const_expr.id),
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_ => None
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},
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_ => None
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};
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tcx.extern_const_statics.borrow_mut().insert(def_id,
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expr_id.unwrap_or(ast::DUMMY_NODE_ID));
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expr_id.map(|id| tcx.map.expect_expr(id))
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}
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}
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#[derive(Clone, PartialEq)]
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pub enum const_val {
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const_float(f64),
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const_int(i64),
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const_uint(u64),
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const_str(InternedString),
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const_binary(Rc<Vec<u8>>),
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const_bool(bool),
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Struct(ast::NodeId),
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Tuple(ast::NodeId)
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}
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pub fn const_expr_to_pat(tcx: &ty::ctxt, expr: &Expr, span: Span) -> P<ast::Pat> {
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let pat = match expr.node {
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ast::ExprTup(ref exprs) =>
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ast::PatTup(exprs.iter().map(|expr| const_expr_to_pat(tcx, &**expr, span)).collect()),
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ast::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::DefStruct(def_id) => def_to_path(tcx, def_id),
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def::DefVariant(_, variant_did, _) => def_to_path(tcx, variant_did),
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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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ast::PatEnum(path, Some(pats))
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}
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ast::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: ast::FieldPat {
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ident: field.ident.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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ast::PatStruct(path.clone(), field_pats, false)
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}
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ast::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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ast::PatVec(pats, None, vec![])
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}
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ast::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::DefStruct(..)) =>
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ast::PatStruct(path.clone(), vec![], false),
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Some(def::DefVariant(..)) =>
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ast::PatEnum(path.clone(), None),
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_ => {
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match lookup_const(tcx, expr) {
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Some(actual) => return const_expr_to_pat(tcx, actual, span),
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_ => unreachable!()
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}
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}
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}
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}
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_ => ast::PatLit(P(expr.clone()))
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};
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P(ast::Pat { id: expr.id, node: pat, span: span })
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}
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pub fn eval_const_expr(tcx: &ty::ctxt, e: &Expr) -> const_val {
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match eval_const_expr_partial(tcx, e, None) {
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Ok(r) => r,
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Err(s) => tcx.sess.span_fatal(s.span, &s.description())
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}
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}
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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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#[derive(Clone)]
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pub enum ErrKind {
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CannotCast,
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CannotCastTo(&'static str),
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InvalidOpForBools(ast::BinOp_),
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InvalidOpForFloats(ast::BinOp_),
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InvalidOpForIntUint(ast::BinOp_),
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InvalidOpForUintInt(ast::BinOp_),
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NegateOnString,
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NegateOnBoolean,
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NegateOnBinary,
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NegateOnStruct,
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NegateOnTuple,
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NotOnFloat,
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NotOnString,
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NotOnBinary,
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NotOnStruct,
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NotOnTuple,
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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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MissingStructField,
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NonConstPath,
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ExpectedConstTuple,
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ExpectedConstStruct,
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TupleIndexOutOfBounds,
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MiscBinaryOp,
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MiscCatchAll,
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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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InvalidOpForBools(_) => "can't do this op on bools".into_cow(),
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InvalidOpForFloats(_) => "can't do this op on floats".into_cow(),
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InvalidOpForIntUint(..) => "can't do this op on an isize and usize".into_cow(),
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InvalidOpForUintInt(..) => "can't do this op on a usize and isize".into_cow(),
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NegateOnString => "negate on string".into_cow(),
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NegateOnBoolean => "negate on boolean".into_cow(),
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NegateOnBinary => "negate on binary literal".into_cow(),
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NegateOnStruct => "negate on struct".into_cow(),
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NegateOnTuple => "negate on tuple".into_cow(),
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NotOnFloat => "not on float or string".into_cow(),
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NotOnString => "not on float or string".into_cow(),
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NotOnBinary => "not on binary literal".into_cow(),
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NotOnStruct => "not on struct".into_cow(),
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NotOnTuple => "not on tuple".into_cow(),
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AddiWithOverflow(..) => "attempted to add with overflow".into_cow(),
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SubiWithOverflow(..) => "attempted to sub with overflow".into_cow(),
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MuliWithOverflow(..) => "attempted to mul with overflow".into_cow(),
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AdduWithOverflow(..) => "attempted to add with overflow".into_cow(),
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SubuWithOverflow(..) => "attempted to sub with overflow".into_cow(),
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MuluWithOverflow(..) => "attempted to mul with overflow".into_cow(),
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DivideByZero => "attempted to divide by zero".into_cow(),
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DivideWithOverflow => "attempted to divide with overflow".into_cow(),
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ModuloByZero => "attempted remainder with a divisor of zero".into_cow(),
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ModuloWithOverflow => "attempted remainder with overflow".into_cow(),
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MissingStructField => "nonexistent struct field".into_cow(),
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NonConstPath => "non-constant path in constant expr".into_cow(),
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ExpectedConstTuple => "expected constant tuple".into_cow(),
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ExpectedConstStruct => "expected constant struct".into_cow(),
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TupleIndexOutOfBounds => "tuple index out of bounds".into_cow(),
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MiscBinaryOp => "bad operands for binary".into_cow(),
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MiscCatchAll => "unsupported constant expr".into_cow(),
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}
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}
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}
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macro_rules! signal {
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($e:expr, $ctor:ident) => {
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return Err(ConstEvalErr { span: $e.span, kind: ErrKind::$ctor })
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};
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($e:expr, $ctor:ident($($arg:expr),*)) => {
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return Err(ConstEvalErr { span: $e.span, kind: ErrKind::$ctor($($arg),*) })
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}
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}
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fn checked_add_int(e: &Expr, a: i64, b: i64) -> Result<const_val, ConstEvalErr> {
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let (ret, oflo) = a.overflowing_add(b);
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if !oflo { Ok(const_int(ret)) } else { signal!(e, AddiWithOverflow(a, b)) }
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}
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fn checked_sub_int(e: &Expr, a: i64, b: i64) -> Result<const_val, ConstEvalErr> {
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let (ret, oflo) = a.overflowing_sub(b);
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if !oflo { Ok(const_int(ret)) } else { signal!(e, SubiWithOverflow(a, b)) }
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}
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fn checked_mul_int(e: &Expr, a: i64, b: i64) -> Result<const_val, ConstEvalErr> {
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let (ret, oflo) = a.overflowing_mul(b);
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if !oflo { Ok(const_int(ret)) } else { signal!(e, MuliWithOverflow(a, b)) }
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}
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fn checked_add_uint(e: &Expr, a: u64, b: u64) -> Result<const_val, ConstEvalErr> {
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let (ret, oflo) = a.overflowing_add(b);
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if !oflo { Ok(const_uint(ret)) } else { signal!(e, AdduWithOverflow(a, b)) }
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}
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fn checked_sub_uint(e: &Expr, a: u64, b: u64) -> Result<const_val, ConstEvalErr> {
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let (ret, oflo) = a.overflowing_sub(b);
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if !oflo { Ok(const_uint(ret)) } else { signal!(e, SubuWithOverflow(a, b)) }
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}
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fn checked_mul_uint(e: &Expr, a: u64, b: u64) -> Result<const_val, ConstEvalErr> {
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let (ret, oflo) = a.overflowing_mul(b);
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if !oflo { Ok(const_uint(ret)) } else { signal!(e, MuluWithOverflow(a, b)) }
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}
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pub fn eval_const_expr_partial<'tcx>(tcx: &ty::ctxt<'tcx>,
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e: &Expr,
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ty_hint: Option<Ty<'tcx>>)
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-> Result<const_val, ConstEvalErr> {
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fn fromb(b: bool) -> const_val { const_int(b as i64) }
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let ety = ty_hint.or_else(|| ty::expr_ty_opt(tcx, e));
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let result = match e.node {
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ast::ExprUnary(ast::UnNeg, ref inner) => {
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match try!(eval_const_expr_partial(tcx, &**inner, ety)) {
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const_float(f) => const_float(-f),
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const_int(i) => const_int(-i),
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const_uint(i) => const_uint(-i),
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const_str(_) => signal!(e, NegateOnString),
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const_bool(_) => signal!(e, NegateOnBoolean),
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const_binary(_) => signal!(e, NegateOnBinary),
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const_val::Tuple(_) => signal!(e, NegateOnTuple),
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const_val::Struct(..) => signal!(e, NegateOnStruct),
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}
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}
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ast::ExprUnary(ast::UnNot, ref inner) => {
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match try!(eval_const_expr_partial(tcx, &**inner, ety)) {
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const_int(i) => const_int(!i),
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const_uint(i) => const_uint(!i),
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const_bool(b) => const_bool(!b),
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const_str(_) => signal!(e, NotOnString),
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const_float(_) => signal!(e, NotOnFloat),
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const_binary(_) => signal!(e, NotOnBinary),
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const_val::Tuple(_) => signal!(e, NotOnTuple),
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const_val::Struct(..) => signal!(e, NotOnStruct),
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}
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}
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ast::ExprBinary(op, ref a, ref b) => {
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let b_ty = match op.node {
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ast::BiShl | ast::BiShr => Some(tcx.types.usize),
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_ => ety
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};
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match (try!(eval_const_expr_partial(tcx, &**a, ety)),
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try!(eval_const_expr_partial(tcx, &**b, b_ty))) {
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(const_float(a), const_float(b)) => {
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match op.node {
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ast::BiAdd => const_float(a + b),
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ast::BiSub => const_float(a - b),
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ast::BiMul => const_float(a * b),
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ast::BiDiv => const_float(a / b),
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ast::BiRem => const_float(a % b),
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ast::BiEq => fromb(a == b),
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ast::BiLt => fromb(a < b),
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ast::BiLe => fromb(a <= b),
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ast::BiNe => fromb(a != b),
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ast::BiGe => fromb(a >= b),
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ast::BiGt => fromb(a > b),
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_ => signal!(e, InvalidOpForFloats(op.node))
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}
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}
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(const_int(a), const_int(b)) => {
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let is_a_min_value = || {
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let int_ty = match ty::expr_ty_opt(tcx, e).map(|ty| &ty.sty) {
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Some(&ty::ty_int(int_ty)) => int_ty,
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_ => return false
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};
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let int_ty = if let ast::TyIs = int_ty {
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tcx.sess.target.int_type
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} else {
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int_ty
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};
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match int_ty {
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ast::TyI8 => (a as i8) == i8::MIN,
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ast::TyI16 => (a as i16) == i16::MIN,
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ast::TyI32 => (a as i32) == i32::MIN,
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ast::TyI64 => (a as i64) == i64::MIN,
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ast::TyIs => unreachable!()
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}
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};
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match op.node {
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ast::BiAdd => try!(checked_add_int(e, a, b)),
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ast::BiSub => try!(checked_sub_int(e, a, b)),
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ast::BiMul => try!(checked_mul_int(e, a, b)),
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ast::BiDiv => {
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if b == 0 {
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signal!(e, DivideByZero);
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} else if b == -1 && is_a_min_value() {
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signal!(e, DivideWithOverflow);
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} else {
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const_int(a / b)
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}
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}
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ast::BiRem => {
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if b == 0 {
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signal!(e, ModuloByZero)
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} else if b == -1 && is_a_min_value() {
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signal!(e, ModuloWithOverflow)
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} else {
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const_int(a % b)
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}
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}
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ast::BiAnd | ast::BiBitAnd => const_int(a & b),
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ast::BiOr | ast::BiBitOr => const_int(a | b),
|
|
ast::BiBitXor => const_int(a ^ b),
|
|
ast::BiShl => const_int(a << b as usize),
|
|
ast::BiShr => const_int(a >> b as usize),
|
|
ast::BiEq => fromb(a == b),
|
|
ast::BiLt => fromb(a < b),
|
|
ast::BiLe => fromb(a <= b),
|
|
ast::BiNe => fromb(a != b),
|
|
ast::BiGe => fromb(a >= b),
|
|
ast::BiGt => fromb(a > b)
|
|
}
|
|
}
|
|
(const_uint(a), const_uint(b)) => {
|
|
match op.node {
|
|
ast::BiAdd => try!(checked_add_uint(e, a, b)),
|
|
ast::BiSub => try!(checked_sub_uint(e, a, b)),
|
|
ast::BiMul => try!(checked_mul_uint(e, a, b)),
|
|
ast::BiDiv if b == 0 => signal!(e, DivideByZero),
|
|
ast::BiDiv => const_uint(a / b),
|
|
ast::BiRem if b == 0 => signal!(e, ModuloByZero),
|
|
ast::BiRem => const_uint(a % b),
|
|
ast::BiAnd | ast::BiBitAnd => const_uint(a & b),
|
|
ast::BiOr | ast::BiBitOr => const_uint(a | b),
|
|
ast::BiBitXor => const_uint(a ^ b),
|
|
ast::BiShl => const_uint(a << b as usize),
|
|
ast::BiShr => const_uint(a >> b as usize),
|
|
ast::BiEq => fromb(a == b),
|
|
ast::BiLt => fromb(a < b),
|
|
ast::BiLe => fromb(a <= b),
|
|
ast::BiNe => fromb(a != b),
|
|
ast::BiGe => fromb(a >= b),
|
|
ast::BiGt => fromb(a > b),
|
|
}
|
|
}
|
|
// shifts can have any integral type as their rhs
|
|
(const_int(a), const_uint(b)) => {
|
|
match op.node {
|
|
ast::BiShl => const_int(a << b as usize),
|
|
ast::BiShr => const_int(a >> b as usize),
|
|
_ => signal!(e, InvalidOpForIntUint(op.node)),
|
|
}
|
|
}
|
|
(const_uint(a), const_int(b)) => {
|
|
match op.node {
|
|
ast::BiShl => const_uint(a << b as usize),
|
|
ast::BiShr => const_uint(a >> b as usize),
|
|
_ => signal!(e, InvalidOpForUintInt(op.node)),
|
|
}
|
|
}
|
|
(const_bool(a), const_bool(b)) => {
|
|
const_bool(match op.node {
|
|
ast::BiAnd => a && b,
|
|
ast::BiOr => a || b,
|
|
ast::BiBitXor => a ^ b,
|
|
ast::BiBitAnd => a & b,
|
|
ast::BiBitOr => a | b,
|
|
ast::BiEq => a == b,
|
|
ast::BiNe => a != b,
|
|
_ => signal!(e, InvalidOpForBools(op.node)),
|
|
})
|
|
}
|
|
|
|
_ => signal!(e, MiscBinaryOp),
|
|
}
|
|
}
|
|
ast::ExprCast(ref base, ref target_ty) => {
|
|
// This tends to get called w/o the type actually having been
|
|
// populated in the ctxt, which was causing things to blow up
|
|
// (#5900). Fall back to doing a limited lookup to get past it.
|
|
let ety = ety.or_else(|| ast_ty_to_prim_ty(tcx, &**target_ty))
|
|
.unwrap_or_else(|| {
|
|
tcx.sess.span_fatal(target_ty.span,
|
|
"target type not found for const cast")
|
|
});
|
|
// Prefer known type to noop, but always have a type hint.
|
|
let base_hint = ty::expr_ty_opt(tcx, &**base).unwrap_or(ety);
|
|
let val = try!(eval_const_expr_partial(tcx, &**base, Some(base_hint)));
|
|
match cast_const(tcx, val, ety) {
|
|
Ok(val) => val,
|
|
Err(kind) => return Err(ConstEvalErr { span: e.span, kind: kind }),
|
|
}
|
|
}
|
|
ast::ExprPath(..) => {
|
|
let opt_def = tcx.def_map.borrow().get(&e.id).map(|d| d.full_def());
|
|
let (const_expr, const_ty) = match opt_def {
|
|
Some(def::DefConst(def_id)) => {
|
|
if ast_util::is_local(def_id) {
|
|
match tcx.map.find(def_id.node) {
|
|
Some(ast_map::NodeItem(it)) => match it.node {
|
|
ast::ItemConst(ref ty, ref expr) => {
|
|
(Some(&**expr), Some(&**ty))
|
|
}
|
|
_ => (None, None)
|
|
},
|
|
_ => (None, None)
|
|
}
|
|
} else {
|
|
(lookup_const_by_id(tcx, def_id), None)
|
|
}
|
|
}
|
|
Some(def::DefVariant(enum_def, variant_def, _)) => {
|
|
(lookup_variant_by_id(tcx, enum_def, variant_def), None)
|
|
}
|
|
_ => (None, None)
|
|
};
|
|
let const_expr = match const_expr {
|
|
Some(actual_e) => actual_e,
|
|
None => signal!(e, NonConstPath)
|
|
};
|
|
let ety = ety.or_else(|| const_ty.and_then(|ty| ast_ty_to_prim_ty(tcx, ty)));
|
|
try!(eval_const_expr_partial(tcx, const_expr, ety))
|
|
}
|
|
ast::ExprLit(ref lit) => {
|
|
lit_to_const(&**lit, ety)
|
|
}
|
|
ast::ExprParen(ref e) => try!(eval_const_expr_partial(tcx, &**e, ety)),
|
|
ast::ExprBlock(ref block) => {
|
|
match block.expr {
|
|
Some(ref expr) => try!(eval_const_expr_partial(tcx, &**expr, ety)),
|
|
None => const_int(0)
|
|
}
|
|
}
|
|
ast::ExprTup(_) => {
|
|
const_val::Tuple(e.id)
|
|
}
|
|
ast::ExprStruct(..) => {
|
|
const_val::Struct(e.id)
|
|
}
|
|
ast::ExprTupField(ref base, index) => {
|
|
if let Ok(c) = eval_const_expr_partial(tcx, base, None) {
|
|
if let const_val::Tuple(tup_id) = c {
|
|
if let ast::ExprTup(ref fields) = tcx.map.expect_expr(tup_id).node {
|
|
if index.node < fields.len() {
|
|
return eval_const_expr_partial(tcx, &fields[index.node], None)
|
|
} else {
|
|
signal!(e, TupleIndexOutOfBounds);
|
|
}
|
|
} else {
|
|
unreachable!()
|
|
}
|
|
} else {
|
|
signal!(base, ExpectedConstTuple);
|
|
}
|
|
} else {
|
|
signal!(base, NonConstPath)
|
|
}
|
|
}
|
|
ast::ExprField(ref base, field_name) => {
|
|
// Get the base expression if it is a struct and it is constant
|
|
if let Ok(c) = eval_const_expr_partial(tcx, base, None) {
|
|
if let const_val::Struct(struct_id) = c {
|
|
if let ast::ExprStruct(_, ref fields, _) = tcx.map.expect_expr(struct_id).node {
|
|
// Check that the given field exists and evaluate it
|
|
if let Some(f) = fields.iter().find(|f| f.ident.node.as_str()
|
|
== field_name.node.as_str()) {
|
|
return eval_const_expr_partial(tcx, &*f.expr, None)
|
|
} else {
|
|
signal!(e, MissingStructField);
|
|
}
|
|
} else {
|
|
unreachable!()
|
|
}
|
|
} else {
|
|
signal!(base, ExpectedConstStruct);
|
|
}
|
|
} else {
|
|
signal!(base, NonConstPath);
|
|
}
|
|
}
|
|
_ => signal!(e, MiscCatchAll)
|
|
};
|
|
|
|
Ok(result)
|
|
}
|
|
|
|
fn cast_const<'tcx>(tcx: &ty::ctxt<'tcx>, val: const_val, ty: Ty) -> Result<const_val, ErrKind> {
|
|
macro_rules! convert_val {
|
|
($intermediate_ty:ty, $const_type:ident, $target_ty:ty) => {
|
|
match val {
|
|
const_bool(b) => Ok($const_type(b as $intermediate_ty as $target_ty)),
|
|
const_uint(u) => Ok($const_type(u as $intermediate_ty as $target_ty)),
|
|
const_int(i) => Ok($const_type(i as $intermediate_ty as $target_ty)),
|
|
const_float(f) => Ok($const_type(f as $intermediate_ty as $target_ty)),
|
|
_ => Err(ErrKind::CannotCastTo(stringify!($const_type))),
|
|
}
|
|
}
|
|
}
|
|
|
|
// Issue #23890: If isize/usize, then dispatch to appropriate target representation type
|
|
match (&ty.sty, tcx.sess.target.int_type, tcx.sess.target.uint_type) {
|
|
(&ty::ty_int(ast::TyIs), ast::TyI32, _) => return convert_val!(i32, const_int, i64),
|
|
(&ty::ty_int(ast::TyIs), ast::TyI64, _) => return convert_val!(i64, const_int, i64),
|
|
(&ty::ty_int(ast::TyIs), _, _) => panic!("unexpected target.int_type"),
|
|
|
|
(&ty::ty_uint(ast::TyUs), _, ast::TyU32) => return convert_val!(u32, const_uint, u64),
|
|
(&ty::ty_uint(ast::TyUs), _, ast::TyU64) => return convert_val!(u64, const_uint, u64),
|
|
(&ty::ty_uint(ast::TyUs), _, _) => panic!("unexpected target.uint_type"),
|
|
|
|
_ => {}
|
|
}
|
|
|
|
match ty.sty {
|
|
ty::ty_int(ast::TyIs) => unreachable!(),
|
|
ty::ty_uint(ast::TyUs) => unreachable!(),
|
|
|
|
ty::ty_int(ast::TyI8) => convert_val!(i8, const_int, i64),
|
|
ty::ty_int(ast::TyI16) => convert_val!(i16, const_int, i64),
|
|
ty::ty_int(ast::TyI32) => convert_val!(i32, const_int, i64),
|
|
ty::ty_int(ast::TyI64) => convert_val!(i64, const_int, i64),
|
|
|
|
ty::ty_uint(ast::TyU8) => convert_val!(u8, const_uint, u64),
|
|
ty::ty_uint(ast::TyU16) => convert_val!(u16, const_uint, u64),
|
|
ty::ty_uint(ast::TyU32) => convert_val!(u32, const_uint, u64),
|
|
ty::ty_uint(ast::TyU64) => convert_val!(u64, const_uint, u64),
|
|
|
|
ty::ty_float(ast::TyF32) => convert_val!(f32, const_float, f64),
|
|
ty::ty_float(ast::TyF64) => convert_val!(f64, const_float, f64),
|
|
_ => Err(ErrKind::CannotCast),
|
|
}
|
|
}
|
|
|
|
fn lit_to_const(lit: &ast::Lit, ty_hint: Option<Ty>) -> const_val {
|
|
match lit.node {
|
|
ast::LitStr(ref s, _) => const_str((*s).clone()),
|
|
ast::LitBinary(ref data) => {
|
|
const_binary(data.clone())
|
|
}
|
|
ast::LitByte(n) => const_uint(n as u64),
|
|
ast::LitChar(n) => const_uint(n as u64),
|
|
ast::LitInt(n, ast::SignedIntLit(_, ast::Plus)) => const_int(n as i64),
|
|
ast::LitInt(n, ast::UnsuffixedIntLit(ast::Plus)) => {
|
|
match ty_hint.map(|ty| &ty.sty) {
|
|
Some(&ty::ty_uint(_)) => const_uint(n),
|
|
_ => const_int(n as i64)
|
|
}
|
|
}
|
|
ast::LitInt(n, ast::SignedIntLit(_, ast::Minus)) |
|
|
ast::LitInt(n, ast::UnsuffixedIntLit(ast::Minus)) => const_int(-(n as i64)),
|
|
ast::LitInt(n, ast::UnsignedIntLit(_)) => const_uint(n),
|
|
ast::LitFloat(ref n, _) |
|
|
ast::LitFloatUnsuffixed(ref n) => {
|
|
const_float(n.parse::<f64>().unwrap() as f64)
|
|
}
|
|
ast::LitBool(b) => const_bool(b)
|
|
}
|
|
}
|
|
|
|
pub fn compare_const_vals(a: &const_val, b: &const_val) -> Option<Ordering> {
|
|
Some(match (a, b) {
|
|
(&const_int(a), &const_int(b)) => a.cmp(&b),
|
|
(&const_uint(a), &const_uint(b)) => a.cmp(&b),
|
|
(&const_float(a), &const_float(b)) => {
|
|
// This is pretty bad but it is the existing behavior.
|
|
if a == b {
|
|
Ordering::Equal
|
|
} else if a < b {
|
|
Ordering::Less
|
|
} else {
|
|
Ordering::Greater
|
|
}
|
|
}
|
|
(&const_str(ref a), &const_str(ref b)) => a.cmp(b),
|
|
(&const_bool(a), &const_bool(b)) => a.cmp(&b),
|
|
(&const_binary(ref a), &const_binary(ref b)) => a.cmp(b),
|
|
_ => return None
|
|
})
|
|
}
|
|
|
|
pub fn compare_lit_exprs<'tcx>(tcx: &ty::ctxt<'tcx>,
|
|
a: &Expr,
|
|
b: &Expr,
|
|
ty_hint: Option<Ty<'tcx>>)
|
|
-> Option<Ordering> {
|
|
let a = match eval_const_expr_partial(tcx, a, ty_hint) {
|
|
Ok(a) => a,
|
|
Err(e) => {
|
|
tcx.sess.span_err(a.span, &e.description());
|
|
return None;
|
|
}
|
|
};
|
|
let b = match eval_const_expr_partial(tcx, b, ty_hint) {
|
|
Ok(b) => b,
|
|
Err(e) => {
|
|
tcx.sess.span_err(b.span, &e.description());
|
|
return None;
|
|
}
|
|
};
|
|
compare_const_vals(&a, &b)
|
|
}
|