a76cb45e34
Ideally float parsing wouldn't fail at all, but for the moment let's give a helpful message. Fixes #31109
1394 lines
54 KiB
Rust
1394 lines
54 KiB
Rust
// Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
|
|
// file at the top-level directory of this distribution and at
|
|
// http://rust-lang.org/COPYRIGHT.
|
|
//
|
|
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
|
|
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
|
|
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
|
|
// option. This file may not be copied, modified, or distributed
|
|
// except according to those terms.
|
|
|
|
//#![allow(non_camel_case_types)]
|
|
|
|
use self::ConstVal::*;
|
|
use self::ErrKind::*;
|
|
use self::EvalHint::*;
|
|
|
|
use front::map as ast_map;
|
|
use front::map::blocks::FnLikeNode;
|
|
use middle::cstore::{self, CrateStore, InlinedItem};
|
|
use middle::{infer, subst, traits};
|
|
use middle::def::Def;
|
|
use middle::subst::Subst;
|
|
use middle::def_id::DefId;
|
|
use middle::pat_util::def_to_path;
|
|
use middle::ty::{self, Ty};
|
|
use middle::astconv_util::ast_ty_to_prim_ty;
|
|
use util::num::ToPrimitive;
|
|
use util::nodemap::NodeMap;
|
|
use session::Session;
|
|
|
|
use graphviz::IntoCow;
|
|
use syntax::ast;
|
|
use rustc_front::hir::Expr;
|
|
use rustc_front::hir;
|
|
use rustc_front::intravisit::FnKind;
|
|
use syntax::codemap::Span;
|
|
use syntax::parse::token::InternedString;
|
|
use syntax::ptr::P;
|
|
use syntax::codemap;
|
|
|
|
use std::borrow::Cow;
|
|
use std::cmp::Ordering;
|
|
use std::collections::hash_map::Entry::Vacant;
|
|
use std::hash;
|
|
use std::mem::transmute;
|
|
use std::{i8, i16, i32, i64, u8, u16, u32, u64};
|
|
use std::rc::Rc;
|
|
|
|
fn lookup_variant_by_id<'a>(tcx: &'a ty::ctxt,
|
|
enum_def: DefId,
|
|
variant_def: DefId)
|
|
-> Option<&'a Expr> {
|
|
fn variant_expr<'a>(variants: &'a [hir::Variant], id: ast::NodeId)
|
|
-> Option<&'a Expr> {
|
|
for variant in variants {
|
|
if variant.node.data.id() == id {
|
|
return variant.node.disr_expr.as_ref().map(|e| &**e);
|
|
}
|
|
}
|
|
None
|
|
}
|
|
|
|
if let Some(enum_node_id) = tcx.map.as_local_node_id(enum_def) {
|
|
let variant_node_id = tcx.map.as_local_node_id(variant_def).unwrap();
|
|
match tcx.map.find(enum_node_id) {
|
|
None => None,
|
|
Some(ast_map::NodeItem(it)) => match it.node {
|
|
hir::ItemEnum(hir::EnumDef { ref variants }, _) => {
|
|
variant_expr(variants, variant_node_id)
|
|
}
|
|
_ => None
|
|
},
|
|
Some(_) => None
|
|
}
|
|
} else {
|
|
None
|
|
}
|
|
}
|
|
|
|
/// * `def_id` is the id of the constant.
|
|
/// * `maybe_ref_id` is the id of the expr referencing the constant.
|
|
/// * `param_substs` is the monomorphization substitution for the expression.
|
|
///
|
|
/// `maybe_ref_id` and `param_substs` are optional and are used for
|
|
/// finding substitutions in associated constants. This generally
|
|
/// happens in late/trans const evaluation.
|
|
pub fn lookup_const_by_id<'a, 'tcx: 'a>(tcx: &'a ty::ctxt<'tcx>,
|
|
def_id: DefId,
|
|
maybe_ref_id: Option<ast::NodeId>,
|
|
param_substs: Option<&'tcx subst::Substs<'tcx>>)
|
|
-> Option<&'tcx Expr> {
|
|
if let Some(node_id) = tcx.map.as_local_node_id(def_id) {
|
|
match tcx.map.find(node_id) {
|
|
None => None,
|
|
Some(ast_map::NodeItem(it)) => match it.node {
|
|
hir::ItemConst(_, ref const_expr) => {
|
|
Some(&*const_expr)
|
|
}
|
|
_ => None
|
|
},
|
|
Some(ast_map::NodeTraitItem(ti)) => match ti.node {
|
|
hir::ConstTraitItem(_, _) => {
|
|
match maybe_ref_id {
|
|
// If we have a trait item, and we know the expression
|
|
// that's the source of the obligation to resolve it,
|
|
// `resolve_trait_associated_const` will select an impl
|
|
// or the default.
|
|
Some(ref_id) => {
|
|
let trait_id = tcx.trait_of_item(def_id)
|
|
.unwrap();
|
|
let mut substs = tcx.node_id_item_substs(ref_id)
|
|
.substs;
|
|
if let Some(param_substs) = param_substs {
|
|
substs = substs.subst(tcx, param_substs);
|
|
}
|
|
resolve_trait_associated_const(tcx, ti, trait_id,
|
|
substs)
|
|
}
|
|
// Technically, without knowing anything about the
|
|
// expression that generates the obligation, we could
|
|
// still return the default if there is one. However,
|
|
// it's safer to return `None` than to return some value
|
|
// that may differ from what you would get from
|
|
// correctly selecting an impl.
|
|
None => None
|
|
}
|
|
}
|
|
_ => None
|
|
},
|
|
Some(ast_map::NodeImplItem(ii)) => match ii.node {
|
|
hir::ImplItemKind::Const(_, ref expr) => {
|
|
Some(&*expr)
|
|
}
|
|
_ => None
|
|
},
|
|
Some(_) => None
|
|
}
|
|
} else {
|
|
match tcx.extern_const_statics.borrow().get(&def_id) {
|
|
Some(&ast::DUMMY_NODE_ID) => return None,
|
|
Some(&expr_id) => {
|
|
return Some(tcx.map.expect_expr(expr_id));
|
|
}
|
|
None => {}
|
|
}
|
|
let mut used_ref_id = false;
|
|
let expr_id = match tcx.sess.cstore.maybe_get_item_ast(tcx, def_id) {
|
|
cstore::FoundAst::Found(&InlinedItem::Item(ref item)) => match item.node {
|
|
hir::ItemConst(_, ref const_expr) => Some(const_expr.id),
|
|
_ => None
|
|
},
|
|
cstore::FoundAst::Found(&InlinedItem::TraitItem(trait_id, ref ti)) => match ti.node {
|
|
hir::ConstTraitItem(_, _) => {
|
|
used_ref_id = true;
|
|
match maybe_ref_id {
|
|
// As mentioned in the comments above for in-crate
|
|
// constants, we only try to find the expression for
|
|
// a trait-associated const if the caller gives us
|
|
// the expression that refers to it.
|
|
Some(ref_id) => {
|
|
let mut substs = tcx.node_id_item_substs(ref_id)
|
|
.substs;
|
|
if let Some(param_substs) = param_substs {
|
|
substs = substs.subst(tcx, param_substs);
|
|
}
|
|
resolve_trait_associated_const(tcx, ti, trait_id,
|
|
substs).map(|e| e.id)
|
|
}
|
|
None => None
|
|
}
|
|
}
|
|
_ => None
|
|
},
|
|
cstore::FoundAst::Found(&InlinedItem::ImplItem(_, ref ii)) => match ii.node {
|
|
hir::ImplItemKind::Const(_, ref expr) => Some(expr.id),
|
|
_ => None
|
|
},
|
|
_ => None
|
|
};
|
|
// If we used the reference expression, particularly to choose an impl
|
|
// of a trait-associated const, don't cache that, because the next
|
|
// lookup with the same def_id may yield a different result.
|
|
if !used_ref_id {
|
|
tcx.extern_const_statics
|
|
.borrow_mut().insert(def_id,
|
|
expr_id.unwrap_or(ast::DUMMY_NODE_ID));
|
|
}
|
|
expr_id.map(|id| tcx.map.expect_expr(id))
|
|
}
|
|
}
|
|
|
|
fn inline_const_fn_from_external_crate(tcx: &ty::ctxt, def_id: DefId)
|
|
-> Option<ast::NodeId> {
|
|
match tcx.extern_const_fns.borrow().get(&def_id) {
|
|
Some(&ast::DUMMY_NODE_ID) => return None,
|
|
Some(&fn_id) => return Some(fn_id),
|
|
None => {}
|
|
}
|
|
|
|
if !tcx.sess.cstore.is_const_fn(def_id) {
|
|
tcx.extern_const_fns.borrow_mut().insert(def_id, ast::DUMMY_NODE_ID);
|
|
return None;
|
|
}
|
|
|
|
let fn_id = match tcx.sess.cstore.maybe_get_item_ast(tcx, def_id) {
|
|
cstore::FoundAst::Found(&InlinedItem::Item(ref item)) => Some(item.id),
|
|
cstore::FoundAst::Found(&InlinedItem::ImplItem(_, ref item)) => Some(item.id),
|
|
_ => None
|
|
};
|
|
tcx.extern_const_fns.borrow_mut().insert(def_id,
|
|
fn_id.unwrap_or(ast::DUMMY_NODE_ID));
|
|
fn_id
|
|
}
|
|
|
|
pub fn lookup_const_fn_by_id<'tcx>(tcx: &ty::ctxt<'tcx>, def_id: DefId)
|
|
-> Option<FnLikeNode<'tcx>>
|
|
{
|
|
let fn_id = if let Some(node_id) = tcx.map.as_local_node_id(def_id) {
|
|
node_id
|
|
} else {
|
|
if let Some(fn_id) = inline_const_fn_from_external_crate(tcx, def_id) {
|
|
fn_id
|
|
} else {
|
|
return None;
|
|
}
|
|
};
|
|
|
|
let fn_like = match FnLikeNode::from_node(tcx.map.get(fn_id)) {
|
|
Some(fn_like) => fn_like,
|
|
None => return None
|
|
};
|
|
|
|
match fn_like.kind() {
|
|
FnKind::ItemFn(_, _, _, hir::Constness::Const, _, _) => {
|
|
Some(fn_like)
|
|
}
|
|
FnKind::Method(_, m, _) => {
|
|
if m.constness == hir::Constness::Const {
|
|
Some(fn_like)
|
|
} else {
|
|
None
|
|
}
|
|
}
|
|
_ => None
|
|
}
|
|
}
|
|
|
|
#[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
|
|
pub enum ConstVal {
|
|
Float(f64),
|
|
Int(i64),
|
|
Uint(u64),
|
|
Str(InternedString),
|
|
ByteStr(Rc<Vec<u8>>),
|
|
Bool(bool),
|
|
Struct(ast::NodeId),
|
|
Tuple(ast::NodeId),
|
|
Function(DefId),
|
|
Array(ast::NodeId, u64),
|
|
Repeat(ast::NodeId, u64),
|
|
}
|
|
|
|
impl hash::Hash for ConstVal {
|
|
fn hash<H: hash::Hasher>(&self, state: &mut H) {
|
|
match *self {
|
|
Float(a) => unsafe { transmute::<_,u64>(a) }.hash(state),
|
|
Int(a) => a.hash(state),
|
|
Uint(a) => a.hash(state),
|
|
Str(ref a) => a.hash(state),
|
|
ByteStr(ref a) => a.hash(state),
|
|
Bool(a) => a.hash(state),
|
|
Struct(a) => a.hash(state),
|
|
Tuple(a) => a.hash(state),
|
|
Function(a) => a.hash(state),
|
|
Array(a, n) => { a.hash(state); n.hash(state) },
|
|
Repeat(a, n) => { a.hash(state); n.hash(state) },
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Note that equality for `ConstVal` means that the it is the same
|
|
/// constant, not that the rust values are equal. In particular, `NaN
|
|
/// == NaN` (at least if it's the same NaN; distinct encodings for NaN
|
|
/// are considering unequal).
|
|
impl PartialEq for ConstVal {
|
|
fn eq(&self, other: &ConstVal) -> bool {
|
|
match (self, other) {
|
|
(&Float(a), &Float(b)) => unsafe{transmute::<_,u64>(a) == transmute::<_,u64>(b)},
|
|
(&Int(a), &Int(b)) => a == b,
|
|
(&Uint(a), &Uint(b)) => a == b,
|
|
(&Str(ref a), &Str(ref b)) => a == b,
|
|
(&ByteStr(ref a), &ByteStr(ref b)) => a == b,
|
|
(&Bool(a), &Bool(b)) => a == b,
|
|
(&Struct(a), &Struct(b)) => a == b,
|
|
(&Tuple(a), &Tuple(b)) => a == b,
|
|
(&Function(a), &Function(b)) => a == b,
|
|
(&Array(a, an), &Array(b, bn)) => (a == b) && (an == bn),
|
|
(&Repeat(a, an), &Repeat(b, bn)) => (a == b) && (an == bn),
|
|
_ => false,
|
|
}
|
|
}
|
|
}
|
|
|
|
impl Eq for ConstVal { }
|
|
|
|
impl ConstVal {
|
|
pub fn description(&self) -> &'static str {
|
|
match *self {
|
|
Float(_) => "float",
|
|
Int(i) if i < 0 => "negative integer",
|
|
Int(_) => "positive integer",
|
|
Uint(_) => "unsigned integer",
|
|
Str(_) => "string literal",
|
|
ByteStr(_) => "byte string literal",
|
|
Bool(_) => "boolean",
|
|
Struct(_) => "struct",
|
|
Tuple(_) => "tuple",
|
|
Function(_) => "function definition",
|
|
Array(..) => "array",
|
|
Repeat(..) => "repeat",
|
|
}
|
|
}
|
|
}
|
|
|
|
pub fn const_expr_to_pat(tcx: &ty::ctxt, expr: &Expr, span: Span) -> P<hir::Pat> {
|
|
let pat = match expr.node {
|
|
hir::ExprTup(ref exprs) =>
|
|
hir::PatTup(exprs.iter().map(|expr| const_expr_to_pat(tcx, &**expr, span)).collect()),
|
|
|
|
hir::ExprCall(ref callee, ref args) => {
|
|
let def = *tcx.def_map.borrow().get(&callee.id).unwrap();
|
|
if let Vacant(entry) = tcx.def_map.borrow_mut().entry(expr.id) {
|
|
entry.insert(def);
|
|
}
|
|
let path = match def.full_def() {
|
|
Def::Struct(def_id) => def_to_path(tcx, def_id),
|
|
Def::Variant(_, variant_did) => def_to_path(tcx, variant_did),
|
|
Def::Fn(..) => return P(hir::Pat {
|
|
id: expr.id,
|
|
node: hir::PatLit(P(expr.clone())),
|
|
span: span,
|
|
}),
|
|
_ => unreachable!()
|
|
};
|
|
let pats = args.iter().map(|expr| const_expr_to_pat(tcx, &**expr, span)).collect();
|
|
hir::PatEnum(path, Some(pats))
|
|
}
|
|
|
|
hir::ExprStruct(ref path, ref fields, None) => {
|
|
let field_pats = fields.iter().map(|field| codemap::Spanned {
|
|
span: codemap::DUMMY_SP,
|
|
node: hir::FieldPat {
|
|
name: field.name.node,
|
|
pat: const_expr_to_pat(tcx, &*field.expr, span),
|
|
is_shorthand: false,
|
|
},
|
|
}).collect();
|
|
hir::PatStruct(path.clone(), field_pats, false)
|
|
}
|
|
|
|
hir::ExprVec(ref exprs) => {
|
|
let pats = exprs.iter().map(|expr| const_expr_to_pat(tcx, &**expr, span)).collect();
|
|
hir::PatVec(pats, None, hir::HirVec::new())
|
|
}
|
|
|
|
hir::ExprPath(_, ref path) => {
|
|
let opt_def = tcx.def_map.borrow().get(&expr.id).map(|d| d.full_def());
|
|
match opt_def {
|
|
Some(Def::Struct(..)) =>
|
|
hir::PatStruct(path.clone(), hir::HirVec::new(), false),
|
|
Some(Def::Variant(..)) =>
|
|
hir::PatEnum(path.clone(), None),
|
|
Some(Def::Const(def_id)) |
|
|
Some(Def::AssociatedConst(def_id)) => {
|
|
let expr = lookup_const_by_id(tcx, def_id, Some(expr.id), None).unwrap();
|
|
return const_expr_to_pat(tcx, expr, span);
|
|
},
|
|
_ => unreachable!(),
|
|
}
|
|
}
|
|
|
|
_ => hir::PatLit(P(expr.clone()))
|
|
};
|
|
P(hir::Pat { id: expr.id, node: pat, span: span })
|
|
}
|
|
|
|
pub fn eval_const_expr(tcx: &ty::ctxt, e: &Expr) -> ConstVal {
|
|
match eval_const_expr_partial(tcx, e, ExprTypeChecked, None) {
|
|
Ok(r) => r,
|
|
Err(s) => tcx.sess.span_fatal(s.span, &s.description())
|
|
}
|
|
}
|
|
|
|
pub type FnArgMap<'a> = Option<&'a NodeMap<ConstVal>>;
|
|
|
|
#[derive(Clone)]
|
|
pub struct ConstEvalErr {
|
|
pub span: Span,
|
|
pub kind: ErrKind,
|
|
}
|
|
|
|
#[derive(Clone)]
|
|
pub enum ErrKind {
|
|
CannotCast,
|
|
CannotCastTo(&'static str),
|
|
InvalidOpForInts(hir::BinOp_),
|
|
InvalidOpForUInts(hir::BinOp_),
|
|
InvalidOpForBools(hir::BinOp_),
|
|
InvalidOpForFloats(hir::BinOp_),
|
|
InvalidOpForIntUint(hir::BinOp_),
|
|
InvalidOpForUintInt(hir::BinOp_),
|
|
NegateOn(ConstVal),
|
|
NotOn(ConstVal),
|
|
CallOn(ConstVal),
|
|
|
|
NegateWithOverflow(i64),
|
|
AddiWithOverflow(i64, i64),
|
|
SubiWithOverflow(i64, i64),
|
|
MuliWithOverflow(i64, i64),
|
|
AdduWithOverflow(u64, u64),
|
|
SubuWithOverflow(u64, u64),
|
|
MuluWithOverflow(u64, u64),
|
|
DivideByZero,
|
|
DivideWithOverflow,
|
|
ModuloByZero,
|
|
ModuloWithOverflow,
|
|
ShiftLeftWithOverflow,
|
|
ShiftRightWithOverflow,
|
|
MissingStructField,
|
|
NonConstPath,
|
|
UnimplementedConstVal(&'static str),
|
|
UnresolvedPath,
|
|
ExpectedConstTuple,
|
|
ExpectedConstStruct,
|
|
TupleIndexOutOfBounds,
|
|
IndexedNonVec,
|
|
IndexNegative,
|
|
IndexNotInt,
|
|
IndexOutOfBounds,
|
|
RepeatCountNotNatural,
|
|
RepeatCountNotInt,
|
|
|
|
MiscBinaryOp,
|
|
MiscCatchAll,
|
|
|
|
IndexOpFeatureGated,
|
|
}
|
|
|
|
impl ConstEvalErr {
|
|
pub fn description(&self) -> Cow<str> {
|
|
use self::ErrKind::*;
|
|
|
|
match self.kind {
|
|
CannotCast => "can't cast this type".into_cow(),
|
|
CannotCastTo(s) => format!("can't cast this type to {}", s).into_cow(),
|
|
InvalidOpForInts(_) => "can't do this op on signed integrals".into_cow(),
|
|
InvalidOpForUInts(_) => "can't do this op on unsigned integrals".into_cow(),
|
|
InvalidOpForBools(_) => "can't do this op on bools".into_cow(),
|
|
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(),
|
|
}
|
|
}
|
|
}
|
|
|
|
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),
|
|
}
|
|
}
|
|
}
|
|
|
|
#[derive(Copy, Clone, PartialEq, Debug)]
|
|
pub enum IntTy { I8, I16, I32, I64 }
|
|
#[derive(Copy, Clone, PartialEq, Debug)]
|
|
pub enum UintTy { U8, U16, U32, U64 }
|
|
|
|
impl IntTy {
|
|
pub fn from(tcx: &ty::ctxt, t: ast::IntTy) -> IntTy {
|
|
let t = if let ast::TyIs = t {
|
|
tcx.sess.target.int_type
|
|
} else {
|
|
t
|
|
};
|
|
match t {
|
|
ast::TyIs => unreachable!(),
|
|
ast::TyI8 => IntTy::I8,
|
|
ast::TyI16 => IntTy::I16,
|
|
ast::TyI32 => IntTy::I32,
|
|
ast::TyI64 => IntTy::I64,
|
|
}
|
|
}
|
|
}
|
|
|
|
impl UintTy {
|
|
pub fn from(tcx: &ty::ctxt, t: ast::UintTy) -> UintTy {
|
|
let t = if let ast::TyUs = t {
|
|
tcx.sess.target.uint_type
|
|
} else {
|
|
t
|
|
};
|
|
match t {
|
|
ast::TyUs => unreachable!(),
|
|
ast::TyU8 => UintTy::U8,
|
|
ast::TyU16 => UintTy::U16,
|
|
ast::TyU32 => UintTy::U32,
|
|
ast::TyU64 => UintTy::U64,
|
|
}
|
|
}
|
|
}
|
|
|
|
macro_rules! signal {
|
|
($e:expr, $exn:expr) => {
|
|
return Err(ConstEvalErr { span: $e.span, kind: $exn })
|
|
}
|
|
}
|
|
|
|
// The const_{int,uint}_checked_{neg,add,sub,mul,div,shl,shr} family
|
|
// of functions catch and signal overflow errors during constant
|
|
// evaluation.
|
|
//
|
|
// They all take the operator's arguments (`a` and `b` if binary), the
|
|
// overall expression (`e`) and, if available, whole expression's
|
|
// concrete type (`opt_ety`).
|
|
//
|
|
// If the whole expression's concrete type is None, then this is a
|
|
// constant evaluation happening before type check (e.g. in the check
|
|
// to confirm that a pattern range's left-side is not greater than its
|
|
// right-side). We do not do arithmetic modulo the type's bitwidth in
|
|
// such a case; we just do 64-bit arithmetic and assume that later
|
|
// passes will do it again with the type information, and thus do the
|
|
// overflow checks then.
|
|
|
|
pub fn const_int_checked_neg<'a>(
|
|
a: i64, e: &'a Expr, opt_ety: Option<IntTy>) -> EvalResult {
|
|
|
|
let (min,max) = match opt_ety {
|
|
// (-i8::MIN is itself not an i8, etc, but this is an easy way
|
|
// to allow literals to pass the check. Of course that does
|
|
// not work for i64::MIN.)
|
|
Some(IntTy::I8) => (-(i8::MAX as i64), -(i8::MIN as i64)),
|
|
Some(IntTy::I16) => (-(i16::MAX as i64), -(i16::MIN as i64)),
|
|
Some(IntTy::I32) => (-(i32::MAX as i64), -(i32::MIN as i64)),
|
|
None | Some(IntTy::I64) => (-i64::MAX, -(i64::MIN+1)),
|
|
};
|
|
|
|
let oflo = a < min || a > max;
|
|
if oflo {
|
|
signal!(e, NegateWithOverflow(a));
|
|
} else {
|
|
Ok(Int(-a))
|
|
}
|
|
}
|
|
|
|
pub fn const_uint_checked_neg<'a>(
|
|
a: u64, _e: &'a Expr, _opt_ety: Option<UintTy>) -> EvalResult {
|
|
// This always succeeds, and by definition, returns `(!a)+1`.
|
|
Ok(Uint((!a).wrapping_add(1)))
|
|
}
|
|
|
|
fn const_uint_not(a: u64, opt_ety: Option<UintTy>) -> ConstVal {
|
|
let mask = match opt_ety {
|
|
Some(UintTy::U8) => u8::MAX as u64,
|
|
Some(UintTy::U16) => u16::MAX as u64,
|
|
Some(UintTy::U32) => u32::MAX as u64,
|
|
None | Some(UintTy::U64) => u64::MAX,
|
|
};
|
|
Uint(!a & mask)
|
|
}
|
|
|
|
macro_rules! overflow_checking_body {
|
|
($a:ident, $b:ident, $ety:ident, $overflowing_op:ident,
|
|
lhs: $to_8_lhs:ident $to_16_lhs:ident $to_32_lhs:ident,
|
|
rhs: $to_8_rhs:ident $to_16_rhs:ident $to_32_rhs:ident $to_64_rhs:ident,
|
|
$EnumTy:ident $T8: ident $T16: ident $T32: ident $T64: ident,
|
|
$result_type: ident) => { {
|
|
let (a,b,opt_ety) = ($a,$b,$ety);
|
|
match opt_ety {
|
|
Some($EnumTy::$T8) => match (a.$to_8_lhs(), b.$to_8_rhs()) {
|
|
(Some(a), Some(b)) => {
|
|
let (a, oflo) = a.$overflowing_op(b);
|
|
(a as $result_type, oflo)
|
|
}
|
|
(None, _) | (_, None) => (0, true)
|
|
},
|
|
Some($EnumTy::$T16) => match (a.$to_16_lhs(), b.$to_16_rhs()) {
|
|
(Some(a), Some(b)) => {
|
|
let (a, oflo) = a.$overflowing_op(b);
|
|
(a as $result_type, oflo)
|
|
}
|
|
(None, _) | (_, None) => (0, true)
|
|
},
|
|
Some($EnumTy::$T32) => match (a.$to_32_lhs(), b.$to_32_rhs()) {
|
|
(Some(a), Some(b)) => {
|
|
let (a, oflo) = a.$overflowing_op(b);
|
|
(a as $result_type, oflo)
|
|
}
|
|
(None, _) | (_, None) => (0, true)
|
|
},
|
|
None | Some($EnumTy::$T64) => match b.$to_64_rhs() {
|
|
Some(b) => a.$overflowing_op(b),
|
|
None => (0, true),
|
|
}
|
|
}
|
|
} }
|
|
}
|
|
|
|
macro_rules! int_arith_body {
|
|
($a:ident, $b:ident, $ety:ident, $overflowing_op:ident) => {
|
|
overflow_checking_body!(
|
|
$a, $b, $ety, $overflowing_op,
|
|
lhs: to_i8 to_i16 to_i32,
|
|
rhs: to_i8 to_i16 to_i32 to_i64, IntTy I8 I16 I32 I64, i64)
|
|
}
|
|
}
|
|
|
|
macro_rules! uint_arith_body {
|
|
($a:ident, $b:ident, $ety:ident, $overflowing_op:ident) => {
|
|
overflow_checking_body!(
|
|
$a, $b, $ety, $overflowing_op,
|
|
lhs: to_u8 to_u16 to_u32,
|
|
rhs: to_u8 to_u16 to_u32 to_u64, UintTy U8 U16 U32 U64, u64)
|
|
}
|
|
}
|
|
|
|
macro_rules! int_shift_body {
|
|
($a:ident, $b:ident, $ety:ident, $overflowing_op:ident) => {
|
|
overflow_checking_body!(
|
|
$a, $b, $ety, $overflowing_op,
|
|
lhs: to_i8 to_i16 to_i32,
|
|
rhs: to_u32 to_u32 to_u32 to_u32, IntTy I8 I16 I32 I64, i64)
|
|
}
|
|
}
|
|
|
|
macro_rules! uint_shift_body {
|
|
($a:ident, $b:ident, $ety:ident, $overflowing_op:ident) => {
|
|
overflow_checking_body!(
|
|
$a, $b, $ety, $overflowing_op,
|
|
lhs: to_u8 to_u16 to_u32,
|
|
rhs: to_u32 to_u32 to_u32 to_u32, UintTy U8 U16 U32 U64, u64)
|
|
}
|
|
}
|
|
|
|
macro_rules! pub_fn_checked_op {
|
|
{$fn_name:ident ($a:ident : $a_ty:ty, $b:ident : $b_ty:ty,.. $WhichTy:ident) {
|
|
$ret_oflo_body:ident $overflowing_op:ident
|
|
$const_ty:ident $signal_exn:expr
|
|
}} => {
|
|
pub fn $fn_name<'a>($a: $a_ty,
|
|
$b: $b_ty,
|
|
e: &'a Expr,
|
|
opt_ety: Option<$WhichTy>) -> EvalResult {
|
|
let (ret, oflo) = $ret_oflo_body!($a, $b, opt_ety, $overflowing_op);
|
|
if !oflo { Ok($const_ty(ret)) } else { signal!(e, $signal_exn) }
|
|
}
|
|
}
|
|
}
|
|
|
|
pub_fn_checked_op!{ const_int_checked_add(a: i64, b: i64,.. IntTy) {
|
|
int_arith_body overflowing_add Int AddiWithOverflow(a, b)
|
|
}}
|
|
|
|
pub_fn_checked_op!{ const_int_checked_sub(a: i64, b: i64,.. IntTy) {
|
|
int_arith_body overflowing_sub Int SubiWithOverflow(a, b)
|
|
}}
|
|
|
|
pub_fn_checked_op!{ const_int_checked_mul(a: i64, b: i64,.. IntTy) {
|
|
int_arith_body overflowing_mul Int MuliWithOverflow(a, b)
|
|
}}
|
|
|
|
pub fn const_int_checked_div<'a>(
|
|
a: i64, b: i64, e: &'a Expr, opt_ety: Option<IntTy>) -> EvalResult {
|
|
if b == 0 { signal!(e, DivideByZero); }
|
|
let (ret, oflo) = int_arith_body!(a, b, opt_ety, overflowing_div);
|
|
if !oflo { Ok(Int(ret)) } else { signal!(e, DivideWithOverflow) }
|
|
}
|
|
|
|
pub fn const_int_checked_rem<'a>(
|
|
a: i64, b: i64, e: &'a Expr, opt_ety: Option<IntTy>) -> EvalResult {
|
|
if b == 0 { signal!(e, ModuloByZero); }
|
|
let (ret, oflo) = int_arith_body!(a, b, opt_ety, overflowing_rem);
|
|
if !oflo { Ok(Int(ret)) } else { signal!(e, ModuloWithOverflow) }
|
|
}
|
|
|
|
pub_fn_checked_op!{ const_int_checked_shl(a: i64, b: i64,.. IntTy) {
|
|
int_shift_body overflowing_shl Int ShiftLeftWithOverflow
|
|
}}
|
|
|
|
pub_fn_checked_op!{ const_int_checked_shl_via_uint(a: i64, b: u64,.. IntTy) {
|
|
int_shift_body overflowing_shl Int ShiftLeftWithOverflow
|
|
}}
|
|
|
|
pub_fn_checked_op!{ const_int_checked_shr(a: i64, b: i64,.. IntTy) {
|
|
int_shift_body overflowing_shr Int ShiftRightWithOverflow
|
|
}}
|
|
|
|
pub_fn_checked_op!{ const_int_checked_shr_via_uint(a: i64, b: u64,.. IntTy) {
|
|
int_shift_body overflowing_shr Int ShiftRightWithOverflow
|
|
}}
|
|
|
|
pub_fn_checked_op!{ const_uint_checked_add(a: u64, b: u64,.. UintTy) {
|
|
uint_arith_body overflowing_add Uint AdduWithOverflow(a, b)
|
|
}}
|
|
|
|
pub_fn_checked_op!{ const_uint_checked_sub(a: u64, b: u64,.. UintTy) {
|
|
uint_arith_body overflowing_sub Uint SubuWithOverflow(a, b)
|
|
}}
|
|
|
|
pub_fn_checked_op!{ const_uint_checked_mul(a: u64, b: u64,.. UintTy) {
|
|
uint_arith_body overflowing_mul Uint MuluWithOverflow(a, b)
|
|
}}
|
|
|
|
pub fn const_uint_checked_div<'a>(
|
|
a: u64, b: u64, e: &'a Expr, opt_ety: Option<UintTy>) -> EvalResult {
|
|
if b == 0 { signal!(e, DivideByZero); }
|
|
let (ret, oflo) = uint_arith_body!(a, b, opt_ety, overflowing_div);
|
|
if !oflo { Ok(Uint(ret)) } else { signal!(e, DivideWithOverflow) }
|
|
}
|
|
|
|
pub fn const_uint_checked_rem<'a>(
|
|
a: u64, b: u64, e: &'a Expr, opt_ety: Option<UintTy>) -> EvalResult {
|
|
if b == 0 { signal!(e, ModuloByZero); }
|
|
let (ret, oflo) = uint_arith_body!(a, b, opt_ety, overflowing_rem);
|
|
if !oflo { Ok(Uint(ret)) } else { signal!(e, ModuloWithOverflow) }
|
|
}
|
|
|
|
pub_fn_checked_op!{ const_uint_checked_shl(a: u64, b: u64,.. UintTy) {
|
|
uint_shift_body overflowing_shl Uint ShiftLeftWithOverflow
|
|
}}
|
|
|
|
pub_fn_checked_op!{ const_uint_checked_shl_via_int(a: u64, b: i64,.. UintTy) {
|
|
uint_shift_body overflowing_shl Uint ShiftLeftWithOverflow
|
|
}}
|
|
|
|
pub_fn_checked_op!{ const_uint_checked_shr(a: u64, b: u64,.. UintTy) {
|
|
uint_shift_body overflowing_shr Uint ShiftRightWithOverflow
|
|
}}
|
|
|
|
pub_fn_checked_op!{ const_uint_checked_shr_via_int(a: u64, b: i64,.. UintTy) {
|
|
uint_shift_body overflowing_shr Uint ShiftRightWithOverflow
|
|
}}
|
|
|
|
/// 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: &ty::ctxt<'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)
|
|
}
|
|
};
|
|
|
|
// If type of expression itself is int or uint, normalize in these
|
|
// bindings so that isize/usize is mapped to a type with an
|
|
// inherently known bitwidth.
|
|
let expr_int_type = ety.and_then(|ty| {
|
|
if let ty::TyInt(t) = ty.sty {
|
|
Some(IntTy::from(tcx, t)) } else { None }
|
|
});
|
|
let expr_uint_type = ety.and_then(|ty| {
|
|
if let ty::TyUint(t) = ty.sty {
|
|
Some(UintTy::from(tcx, t)) } else { None }
|
|
});
|
|
|
|
let result = match e.node {
|
|
hir::ExprUnary(hir::UnNeg, ref inner) => {
|
|
match try!(eval_const_expr_partial(tcx, &**inner, ty_hint, fn_args)) {
|
|
Float(f) => Float(-f),
|
|
Int(n) => try!(const_int_checked_neg(n, e, expr_int_type)),
|
|
Uint(i) => {
|
|
try!(const_uint_checked_neg(i, e, expr_uint_type))
|
|
}
|
|
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)) {
|
|
Int(i) => Int(!i),
|
|
Uint(i) => const_uint_not(i, expr_uint_type),
|
|
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.checked_or(tcx.types.usize),
|
|
_ => ty_hint
|
|
};
|
|
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)),
|
|
}
|
|
}
|
|
(Int(a), Int(b)) => {
|
|
match op.node {
|
|
hir::BiAdd => try!(const_int_checked_add(a,b,e,expr_int_type)),
|
|
hir::BiSub => try!(const_int_checked_sub(a,b,e,expr_int_type)),
|
|
hir::BiMul => try!(const_int_checked_mul(a,b,e,expr_int_type)),
|
|
hir::BiDiv => try!(const_int_checked_div(a,b,e,expr_int_type)),
|
|
hir::BiRem => try!(const_int_checked_rem(a,b,e,expr_int_type)),
|
|
hir::BiBitAnd => Int(a & b),
|
|
hir::BiBitOr => Int(a | b),
|
|
hir::BiBitXor => Int(a ^ b),
|
|
hir::BiShl => try!(const_int_checked_shl(a,b,e,expr_int_type)),
|
|
hir::BiShr => try!(const_int_checked_shr(a,b,e,expr_int_type)),
|
|
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, InvalidOpForInts(op.node)),
|
|
}
|
|
}
|
|
(Uint(a), Uint(b)) => {
|
|
match op.node {
|
|
hir::BiAdd => try!(const_uint_checked_add(a,b,e,expr_uint_type)),
|
|
hir::BiSub => try!(const_uint_checked_sub(a,b,e,expr_uint_type)),
|
|
hir::BiMul => try!(const_uint_checked_mul(a,b,e,expr_uint_type)),
|
|
hir::BiDiv => try!(const_uint_checked_div(a,b,e,expr_uint_type)),
|
|
hir::BiRem => try!(const_uint_checked_rem(a,b,e,expr_uint_type)),
|
|
hir::BiBitAnd => Uint(a & b),
|
|
hir::BiBitOr => Uint(a | b),
|
|
hir::BiBitXor => Uint(a ^ b),
|
|
hir::BiShl => try!(const_uint_checked_shl(a,b,e,expr_uint_type)),
|
|
hir::BiShr => try!(const_uint_checked_shr(a,b,e,expr_uint_type)),
|
|
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, InvalidOpForUInts(op.node)),
|
|
}
|
|
}
|
|
// shifts can have any integral type as their rhs
|
|
(Int(a), Uint(b)) => {
|
|
match op.node {
|
|
hir::BiShl => try!(const_int_checked_shl_via_uint(a,b,e,expr_int_type)),
|
|
hir::BiShr => try!(const_int_checked_shr_via_uint(a,b,e,expr_int_type)),
|
|
_ => signal!(e, InvalidOpForIntUint(op.node)),
|
|
}
|
|
}
|
|
(Uint(a), Int(b)) => {
|
|
match op.node {
|
|
hir::BiShl => try!(const_uint_checked_shl_via_int(a,b,e,expr_uint_type)),
|
|
hir::BiShr => try!(const_uint_checked_shr_via_int(a,b,e,expr_uint_type)),
|
|
_ => signal!(e, InvalidOpForUintInt(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 = 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")
|
|
});
|
|
|
|
let base_hint = if let ExprTypeChecked = ty_hint {
|
|
ExprTypeChecked
|
|
} else {
|
|
// FIXME (#23833): the type-hint can cause problems,
|
|
// e.g. `(i8::MAX + 1_i8) as u32` feeds in `u32` as result
|
|
// type to the sum, and thus no overflow is signaled.
|
|
match tcx.expr_ty_opt(&base) {
|
|
Some(t) => UncheckedExprHint(t),
|
|
None => ty_hint
|
|
}
|
|
};
|
|
|
|
let val = try!(eval_const_expr_partial(tcx, &**base, base_hint, fn_args));
|
|
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);
|
|
}
|
|
Some(def.full_def())
|
|
} else {
|
|
None
|
|
};
|
|
let (const_expr, const_ty) = match opt_def {
|
|
Some(Def::Const(def_id)) => {
|
|
if let Some(node_id) = tcx.map.as_local_node_id(def_id) {
|
|
match tcx.map.find(node_id) {
|
|
Some(ast_map::NodeItem(it)) => match it.node {
|
|
hir::ItemConst(ref ty, ref expr) => {
|
|
(Some(&**expr), Some(&**ty))
|
|
}
|
|
_ => (None, None)
|
|
},
|
|
_ => (None, None)
|
|
}
|
|
} else {
|
|
(lookup_const_by_id(tcx, def_id, Some(e.id), None), None)
|
|
}
|
|
}
|
|
Some(Def::AssociatedConst(def_id)) => {
|
|
if let Some(node_id) = tcx.map.as_local_node_id(def_id) {
|
|
match tcx.impl_or_trait_item(def_id).container() {
|
|
ty::TraitContainer(trait_id) => match tcx.map.find(node_id) {
|
|
Some(ast_map::NodeTraitItem(ti)) => match ti.node {
|
|
hir::ConstTraitItem(ref ty, _) => {
|
|
if let ExprTypeChecked = ty_hint {
|
|
let substs = tcx.node_id_item_substs(e.id).substs;
|
|
(resolve_trait_associated_const(tcx,
|
|
ti,
|
|
trait_id,
|
|
substs),
|
|
Some(&**ty))
|
|
} else {
|
|
(None, None)
|
|
}
|
|
}
|
|
_ => (None, None)
|
|
},
|
|
_ => (None, None)
|
|
},
|
|
ty::ImplContainer(_) => match tcx.map.find(node_id) {
|
|
Some(ast_map::NodeImplItem(ii)) => match ii.node {
|
|
hir::ImplItemKind::Const(ref ty, ref expr) => {
|
|
(Some(&**expr), Some(&**ty))
|
|
}
|
|
_ => (None, None)
|
|
},
|
|
_ => (None, None)
|
|
},
|
|
}
|
|
} else {
|
|
(lookup_const_by_id(tcx, def_id, Some(e.id), None), None)
|
|
}
|
|
}
|
|
Some(Def::Variant(enum_def, variant_def)) => {
|
|
(lookup_variant_by_id(tcx, enum_def, variant_def), None)
|
|
}
|
|
Some(Def::Struct(..)) => {
|
|
return Ok(ConstVal::Struct(e.id))
|
|
}
|
|
Some(Def::Local(_, id)) => {
|
|
debug!("Def::Local({:?}): {:?}", id, fn_args);
|
|
if let Some(val) = fn_args.and_then(|args| args.get(&id)) {
|
|
return Ok(val.clone());
|
|
} else {
|
|
(None, None)
|
|
}
|
|
},
|
|
Some(Def::Method(id)) | Some(Def::Fn(id)) => return Ok(Function(id)),
|
|
_ => (None, None)
|
|
};
|
|
let const_expr = match const_expr {
|
|
Some(actual_e) => actual_e,
|
|
None => signal!(e, NonConstPath)
|
|
};
|
|
let item_hint = if let UncheckedExprNoHint = ty_hint {
|
|
match const_ty {
|
|
Some(ty) => match ast_ty_to_prim_ty(tcx, ty) {
|
|
Some(ty) => UncheckedExprHint(ty),
|
|
None => UncheckedExprNoHint
|
|
},
|
|
None => UncheckedExprNoHint
|
|
}
|
|
} else {
|
|
ty_hint
|
|
};
|
|
try!(eval_const_expr_partial(tcx, const_expr, item_hint, fn_args))
|
|
}
|
|
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_val = try!(eval_const_expr_partial(
|
|
tcx,
|
|
arg_expr,
|
|
sub_ty_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) => lit_to_const(tcx.sess, e.span, &**lit, ety),
|
|
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)) {
|
|
Int(i) if i >= 0 => i as u64,
|
|
Int(_) => signal!(idx, IndexNegative),
|
|
Uint(i) => i,
|
|
_ => signal!(idx, IndexNotInt),
|
|
};
|
|
match arr {
|
|
Array(_, n) if idx >= n => signal!(e, IndexOutOfBounds),
|
|
Array(v, _) => if let hir::ExprVec(ref v) = tcx.map.expect_expr(v).node {
|
|
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 as usize >= data.len()
|
|
=> signal!(e, IndexOutOfBounds),
|
|
ByteStr(data) => Uint(data[idx as usize] as u64),
|
|
|
|
Str(ref s) if idx as usize >= s.len()
|
|
=> signal!(e, IndexOutOfBounds),
|
|
Str(_) => unimplemented!(), // there's no const_char type
|
|
_ => 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)) {
|
|
Int(i) if i >= 0 => i as u64,
|
|
Int(_) => signal!(e, RepeatCountNotNatural),
|
|
Uint(i) => i,
|
|
_ => 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() {
|
|
return eval_const_expr_partial(tcx, &fields[index.node], base_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) {
|
|
return eval_const_expr_partial(tcx, &*f.expr, base_hint, fn_args)
|
|
} else {
|
|
signal!(e, MissingStructField);
|
|
}
|
|
} else {
|
|
unreachable!()
|
|
}
|
|
} else {
|
|
signal!(base, ExpectedConstStruct);
|
|
}
|
|
}
|
|
_ => signal!(e, MiscCatchAll)
|
|
};
|
|
|
|
Ok(result)
|
|
}
|
|
|
|
fn resolve_trait_associated_const<'a, 'tcx: 'a>(tcx: &'a ty::ctxt<'tcx>,
|
|
ti: &'tcx hir::TraitItem,
|
|
trait_id: DefId,
|
|
rcvr_substs: subst::Substs<'tcx>)
|
|
-> Option<&'tcx Expr>
|
|
{
|
|
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);
|
|
|
|
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
|
|
}
|
|
};
|
|
|
|
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),
|
|
None => match ti.node {
|
|
hir::ConstTraitItem(_, Some(ref expr)) => Some(&*expr),
|
|
_ => None,
|
|
},
|
|
}
|
|
}
|
|
_ => {
|
|
tcx.sess.span_bug(
|
|
ti.span,
|
|
"resolve_trait_associated_const: unexpected vtable type")
|
|
}
|
|
}
|
|
}
|
|
|
|
fn cast_const<'tcx>(tcx: &ty::ctxt<'tcx>, val: ConstVal, ty: Ty) -> CastResult {
|
|
macro_rules! convert_val {
|
|
($intermediate_ty:ty, $const_type:ident, $target_ty:ty) => {
|
|
match val {
|
|
Bool(b) => Ok($const_type(b as u64 as $intermediate_ty as $target_ty)),
|
|
Uint(u) => Ok($const_type(u as $intermediate_ty as $target_ty)),
|
|
Int(i) => Ok($const_type(i as $intermediate_ty as $target_ty)),
|
|
Float(f) => Ok($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::TyInt(ast::TyIs), ast::TyI32, _) => return convert_val!(i32, Int, i64),
|
|
(&ty::TyInt(ast::TyIs), ast::TyI64, _) => return convert_val!(i64, Int, i64),
|
|
(&ty::TyInt(ast::TyIs), _, _) => panic!("unexpected target.int_type"),
|
|
|
|
(&ty::TyUint(ast::TyUs), _, ast::TyU32) => return convert_val!(u32, Uint, u64),
|
|
(&ty::TyUint(ast::TyUs), _, ast::TyU64) => return convert_val!(u64, Uint, u64),
|
|
(&ty::TyUint(ast::TyUs), _, _) => panic!("unexpected target.uint_type"),
|
|
|
|
_ => {}
|
|
}
|
|
|
|
match ty.sty {
|
|
ty::TyInt(ast::TyIs) => unreachable!(),
|
|
ty::TyUint(ast::TyUs) => unreachable!(),
|
|
|
|
ty::TyInt(ast::TyI8) => convert_val!(i8, Int, i64),
|
|
ty::TyInt(ast::TyI16) => convert_val!(i16, Int, i64),
|
|
ty::TyInt(ast::TyI32) => convert_val!(i32, Int, i64),
|
|
ty::TyInt(ast::TyI64) => convert_val!(i64, Int, i64),
|
|
|
|
ty::TyUint(ast::TyU8) => convert_val!(u8, Uint, u64),
|
|
ty::TyUint(ast::TyU16) => convert_val!(u16, Uint, u64),
|
|
ty::TyUint(ast::TyU32) => convert_val!(u32, Uint, u64),
|
|
ty::TyUint(ast::TyU64) => convert_val!(u64, Uint, u64),
|
|
|
|
ty::TyFloat(ast::TyF32) => convert_val!(f32, Float, f64),
|
|
ty::TyFloat(ast::TyF64) => convert_val!(f64, Float, f64),
|
|
_ => Err(ErrKind::CannotCast),
|
|
}
|
|
}
|
|
|
|
fn lit_to_const(sess: &Session, span: Span, lit: &ast::Lit, ty_hint: Option<Ty>) -> ConstVal {
|
|
match lit.node {
|
|
ast::LitStr(ref s, _) => Str((*s).clone()),
|
|
ast::LitByteStr(ref data) => {
|
|
ByteStr(data.clone())
|
|
}
|
|
ast::LitByte(n) => Uint(n as u64),
|
|
ast::LitChar(n) => Uint(n as u64),
|
|
ast::LitInt(n, ast::SignedIntLit(_, ast::Plus)) => Int(n as i64),
|
|
ast::LitInt(n, ast::UnsuffixedIntLit(ast::Plus)) => {
|
|
match ty_hint.map(|ty| &ty.sty) {
|
|
Some(&ty::TyUint(_)) => Uint(n),
|
|
_ => Int(n as i64)
|
|
}
|
|
}
|
|
ast::LitInt(n, ast::SignedIntLit(_, ast::Minus)) |
|
|
ast::LitInt(n, ast::UnsuffixedIntLit(ast::Minus)) => Int(-(n as i64)),
|
|
ast::LitInt(n, ast::UnsignedIntLit(_)) => Uint(n),
|
|
ast::LitFloat(ref n, _) |
|
|
ast::LitFloatUnsuffixed(ref n) => {
|
|
if let Ok(x) = n.parse::<f64>() {
|
|
Float(x)
|
|
} else {
|
|
// FIXME(#31407) this is only necessary because float parsing is buggy
|
|
sess.span_bug(span, "could not evaluate float literal (see issue #31407)");
|
|
}
|
|
}
|
|
ast::LitBool(b) => Bool(b)
|
|
}
|
|
}
|
|
|
|
pub fn compare_const_vals(a: &ConstVal, b: &ConstVal) -> Option<Ordering> {
|
|
Some(match (a, b) {
|
|
(&Int(a), &Int(b)) => a.cmp(&b),
|
|
(&Uint(a), &Uint(b)) => a.cmp(&b),
|
|
(&Float(a), &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
|
|
}
|
|
}
|
|
(&Str(ref a), &Str(ref b)) => a.cmp(b),
|
|
(&Bool(a), &Bool(b)) => a.cmp(&b),
|
|
(&ByteStr(ref a), &ByteStr(ref b)) => a.cmp(b),
|
|
_ => return None
|
|
})
|
|
}
|
|
|
|
pub fn compare_lit_exprs<'tcx>(tcx: &ty::ctxt<'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)
|
|
}
|