#![allow(clippy::float_cmp)]
-use crate::utils::{clip, get_def_path, sext, unsext};
+use crate::utils::{clip, higher, sext, unsext};
use if_chain::if_chain;
-use rustc::hir::def::Def;
+use rustc::hir::def::{DefKind, Res};
use rustc::hir::*;
use rustc::lint::LateContext;
use rustc::ty::subst::{Subst, SubstsRef};
use rustc_data_structures::sync::Lrc;
use std::cmp::Ordering::{self, Equal};
use std::cmp::PartialOrd;
-use std::convert::TryFrom;
use std::convert::TryInto;
use std::hash::{Hash, Hasher};
use syntax::ast::{FloatTy, LitKind};
-use syntax::ptr::P;
use syntax_pos::symbol::Symbol;
/// A `LitKind`-like enum to fold constant `Expr`s into.
Repeat(Box<Constant>, u64),
/// A tuple of constants.
Tuple(Vec<Constant>),
+ /// A raw pointer.
+ RawPtr(u128),
/// A literal with syntax error.
Err(Symbol),
}
impl PartialEq for Constant {
fn eq(&self, other: &Self) -> bool {
match (self, other) {
- (&Constant::Str(ref ls), &Constant::Str(ref rs)) => ls == rs,
- (&Constant::Binary(ref l), &Constant::Binary(ref r)) => l == r,
- (&Constant::Char(l), &Constant::Char(r)) => l == r,
- (&Constant::Int(l), &Constant::Int(r)) => l == r,
- (&Constant::F64(l), &Constant::F64(r)) => {
+ (&Self::Str(ref ls), &Self::Str(ref rs)) => ls == rs,
+ (&Self::Binary(ref l), &Self::Binary(ref r)) => l == r,
+ (&Self::Char(l), &Self::Char(r)) => l == r,
+ (&Self::Int(l), &Self::Int(r)) => l == r,
+ (&Self::F64(l), &Self::F64(r)) => {
// We want `Fw32 == FwAny` and `FwAny == Fw64`, and by transitivity we must have
// `Fw32 == Fw64`, so don’t compare them.
// `to_bits` is required to catch non-matching 0.0, -0.0, and NaNs.
l.to_bits() == r.to_bits()
},
- (&Constant::F32(l), &Constant::F32(r)) => {
+ (&Self::F32(l), &Self::F32(r)) => {
// We want `Fw32 == FwAny` and `FwAny == Fw64`, and by transitivity we must have
// `Fw32 == Fw64`, so don’t compare them.
// `to_bits` is required to catch non-matching 0.0, -0.0, and NaNs.
f64::from(l).to_bits() == f64::from(r).to_bits()
},
- (&Constant::Bool(l), &Constant::Bool(r)) => l == r,
- (&Constant::Vec(ref l), &Constant::Vec(ref r)) | (&Constant::Tuple(ref l), &Constant::Tuple(ref r)) => {
- l == r
- },
- (&Constant::Repeat(ref lv, ref ls), &Constant::Repeat(ref rv, ref rs)) => ls == rs && lv == rv,
+ (&Self::Bool(l), &Self::Bool(r)) => l == r,
+ (&Self::Vec(ref l), &Self::Vec(ref r)) | (&Self::Tuple(ref l), &Self::Tuple(ref r)) => l == r,
+ (&Self::Repeat(ref lv, ref ls), &Self::Repeat(ref rv, ref rs)) => ls == rs && lv == rv,
// TODO: are there inter-type equalities?
_ => false,
}
where
H: Hasher,
{
+ std::mem::discriminant(self).hash(state);
match *self {
- Constant::Str(ref s) => {
+ Self::Str(ref s) => {
s.hash(state);
},
- Constant::Binary(ref b) => {
+ Self::Binary(ref b) => {
b.hash(state);
},
- Constant::Char(c) => {
+ Self::Char(c) => {
c.hash(state);
},
- Constant::Int(i) => {
+ Self::Int(i) => {
i.hash(state);
},
- Constant::F32(f) => {
+ Self::F32(f) => {
f64::from(f).to_bits().hash(state);
},
- Constant::F64(f) => {
+ Self::F64(f) => {
f.to_bits().hash(state);
},
- Constant::Bool(b) => {
+ Self::Bool(b) => {
b.hash(state);
},
- Constant::Vec(ref v) | Constant::Tuple(ref v) => {
+ Self::Vec(ref v) | Self::Tuple(ref v) => {
v.hash(state);
},
- Constant::Repeat(ref c, l) => {
+ Self::Repeat(ref c, l) => {
c.hash(state);
l.hash(state);
},
- Constant::Err(ref s) => {
+ Self::RawPtr(u) => {
+ u.hash(state);
+ },
+ Self::Err(ref s) => {
s.hash(state);
},
}
}
impl Constant {
- pub fn partial_cmp(tcx: TyCtxt<'_, '_, '_>, cmp_type: ty::Ty<'_>, left: &Self, right: &Self) -> Option<Ordering> {
+ pub fn partial_cmp(tcx: TyCtxt<'_>, cmp_type: Ty<'_>, left: &Self, right: &Self) -> Option<Ordering> {
match (left, right) {
- (&Constant::Str(ref ls), &Constant::Str(ref rs)) => Some(ls.cmp(rs)),
- (&Constant::Char(ref l), &Constant::Char(ref r)) => Some(l.cmp(r)),
- (&Constant::Int(l), &Constant::Int(r)) => {
+ (&Self::Str(ref ls), &Self::Str(ref rs)) => Some(ls.cmp(rs)),
+ (&Self::Char(ref l), &Self::Char(ref r)) => Some(l.cmp(r)),
+ (&Self::Int(l), &Self::Int(r)) => {
if let ty::Int(int_ty) = cmp_type.sty {
Some(sext(tcx, l, int_ty).cmp(&sext(tcx, r, int_ty)))
} else {
Some(l.cmp(&r))
}
},
- (&Constant::F64(l), &Constant::F64(r)) => l.partial_cmp(&r),
- (&Constant::F32(l), &Constant::F32(r)) => l.partial_cmp(&r),
- (&Constant::Bool(ref l), &Constant::Bool(ref r)) => Some(l.cmp(r)),
- (&Constant::Tuple(ref l), &Constant::Tuple(ref r)) | (&Constant::Vec(ref l), &Constant::Vec(ref r)) => l
+ (&Self::F64(l), &Self::F64(r)) => l.partial_cmp(&r),
+ (&Self::F32(l), &Self::F32(r)) => l.partial_cmp(&r),
+ (&Self::Bool(ref l), &Self::Bool(ref r)) => Some(l.cmp(r)),
+ (&Self::Tuple(ref l), &Self::Tuple(ref r)) | (&Self::Vec(ref l), &Self::Vec(ref r)) => l
.iter()
.zip(r.iter())
.map(|(li, ri)| Self::partial_cmp(tcx, cmp_type, li, ri))
.find(|r| r.map_or(true, |o| o != Ordering::Equal))
.unwrap_or_else(|| Some(l.len().cmp(&r.len()))),
- (&Constant::Repeat(ref lv, ref ls), &Constant::Repeat(ref rv, ref rs)) => {
+ (&Self::Repeat(ref lv, ref ls), &Self::Repeat(ref rv, ref rs)) => {
match Self::partial_cmp(tcx, cmp_type, lv, rv) {
Some(Equal) => Some(ls.cmp(rs)),
x => x,
}
/// Parses a `LitKind` to a `Constant`.
-pub fn lit_to_constant<'tcx>(lit: &LitKind, ty: Ty<'tcx>) -> Constant {
+pub fn lit_to_constant(lit: &LitKind, ty: Ty<'_>) -> Constant {
use syntax::ast::*;
match *lit {
e: &Expr,
) -> Option<(Constant, bool)> {
let mut cx = ConstEvalLateContext {
- tcx: lcx.tcx,
+ lcx,
tables,
param_env: lcx.param_env,
needed_resolution: false,
constant(lcx, tables, e).and_then(|(cst, res)| if res { None } else { Some(cst) })
}
-/// Creates a `ConstEvalLateContext` from the given `LateContext` and `TypeckTables`
+/// Creates a `ConstEvalLateContext` from the given `LateContext` and `TypeckTables`.
pub fn constant_context<'c, 'cc>(
- lcx: &LateContext<'c, 'cc>,
+ lcx: &'c LateContext<'c, 'cc>,
tables: &'c ty::TypeckTables<'cc>,
) -> ConstEvalLateContext<'c, 'cc> {
ConstEvalLateContext {
- tcx: lcx.tcx,
+ lcx,
tables,
param_env: lcx.param_env,
needed_resolution: false,
}
}
-pub struct ConstEvalLateContext<'a, 'tcx: 'a> {
- tcx: TyCtxt<'a, 'tcx, 'tcx>,
+pub struct ConstEvalLateContext<'a, 'tcx> {
+ lcx: &'a LateContext<'a, 'tcx>,
tables: &'a ty::TypeckTables<'tcx>,
param_env: ty::ParamEnv<'tcx>,
needed_resolution: bool,
}
impl<'c, 'cc> ConstEvalLateContext<'c, 'cc> {
- /// simple constant folding: Insert an expression, get a constant or none.
+ /// Simple constant folding: Insert an expression, get a constant or none.
pub fn expr(&mut self, e: &Expr) -> Option<Constant> {
+ if let Some((ref cond, ref then, otherwise)) = higher::if_block(&e) {
+ return self.ifthenelse(cond, then, otherwise);
+ }
match e.node {
ExprKind::Path(ref qpath) => self.fetch_path(qpath, e.hir_id),
ExprKind::Block(ref block, _) => self.block(block),
- ExprKind::If(ref cond, ref then, ref otherwise) => self.ifthenelse(cond, then, otherwise),
ExprKind::Lit(ref lit) => Some(lit_to_constant(&lit.node, self.tables.expr_ty(e))),
ExprKind::Array(ref vec) => self.multi(vec).map(Constant::Vec),
ExprKind::Tup(ref tup) => self.multi(tup).map(Constant::Tuple),
ExprKind::Repeat(ref value, _) => {
let n = match self.tables.expr_ty(e).sty {
- ty::Array(_, n) => n.assert_usize(self.tcx).expect("array length"),
+ ty::Array(_, n) => n.eval_usize(self.lcx.tcx, self.lcx.param_env),
_ => span_bug!(e.span, "typeck error"),
};
self.expr(value).map(|v| Constant::Repeat(Box::new(v), n))
}),
ExprKind::Binary(op, ref left, ref right) => self.binop(op, left, right),
ExprKind::Call(ref callee, ref args) => {
- // We only handle a few const functions for now
+ // We only handle a few const functions for now.
if_chain! {
if args.is_empty();
if let ExprKind::Path(qpath) = &callee.node;
- let def = self.tables.qpath_def(qpath, callee.hir_id);
- if let Some(def_id) = def.opt_def_id();
- let def_path = get_def_path(self.tcx, def_id);
- if let &["core", "num", impl_ty, "max_value"] = &def_path[..];
+ let res = self.tables.qpath_res(qpath, callee.hir_id);
+ if let Some(def_id) = res.opt_def_id();
+ let get_def_path = self.lcx.get_def_path(def_id, );
+ let def_path = get_def_path
+ .iter()
+ .copied()
+ .map(Symbol::as_str)
+ .collect::<Vec<_>>();
+ if def_path[0] == "core";
+ if def_path[1] == "num";
+ if def_path[3] == "max_value";
+ if def_path.len() == 4;
then {
- let value = match impl_ty {
+ let value = match &*def_path[2] {
"<impl i8>" => i8::max_value() as u128,
"<impl i16>" => i16::max_value() as u128,
"<impl i32>" => i32::max_value() as u128,
}
}
},
- // TODO: add other expressions
+ // TODO: add other expressions.
_ => None,
}
}
#[allow(clippy::cast_possible_wrap)]
- fn constant_not(&self, o: &Constant, ty: ty::Ty<'_>) -> Option<Constant> {
+ fn constant_not(&self, o: &Constant, ty: Ty<'_>) -> Option<Constant> {
use self::Constant::*;
match *o {
Bool(b) => Some(Bool(!b)),
Int(value) => {
let value = !value;
match ty.sty {
- ty::Int(ity) => Some(Int(unsext(self.tcx, value as i128, ity))),
- ty::Uint(ity) => Some(Int(clip(self.tcx, value, ity))),
+ ty::Int(ity) => Some(Int(unsext(self.lcx.tcx, value as i128, ity))),
+ ty::Uint(ity) => Some(Int(clip(self.lcx.tcx, value, ity))),
_ => None,
}
},
}
}
- fn constant_negate(&self, o: &Constant, ty: ty::Ty<'_>) -> Option<Constant> {
+ fn constant_negate(&self, o: &Constant, ty: Ty<'_>) -> Option<Constant> {
use self::Constant::*;
match *o {
Int(value) => {
_ => return None,
};
// sign extend
- let value = sext(self.tcx, value, ity);
+ let value = sext(self.lcx.tcx, value, ity);
let value = value.checked_neg()?;
// clear unused bits
- Some(Int(unsext(self.tcx, value, ity)))
+ Some(Int(unsext(self.lcx.tcx, value, ity)))
},
F32(f) => Some(F32(-f)),
F64(f) => Some(F64(-f)),
}
}
- /// create `Some(Vec![..])` of all constants, unless there is any
- /// non-constant part
+ /// Create `Some(Vec![..])` of all constants, unless there is any
+ /// non-constant part.
fn multi(&mut self, vec: &[Expr]) -> Option<Vec<Constant>> {
vec.iter().map(|elem| self.expr(elem)).collect::<Option<_>>()
}
- /// lookup a possibly constant expression from a ExprKind::Path
+ /// Lookup a possibly constant expression from a ExprKind::Path.
fn fetch_path(&mut self, qpath: &QPath, id: HirId) -> Option<Constant> {
use rustc::mir::interpret::GlobalId;
- let def = self.tables.qpath_def(qpath, id);
- match def {
- Def::Const(def_id) | Def::AssociatedConst(def_id) => {
+ let res = self.tables.qpath_res(qpath, id);
+ match res {
+ Res::Def(DefKind::Const, def_id) | Res::Def(DefKind::AssocConst, def_id) => {
let substs = self.tables.node_substs(id);
let substs = if self.substs.is_empty() {
substs
} else {
- substs.subst(self.tcx, self.substs)
+ substs.subst(self.lcx.tcx, self.substs)
};
- let instance = Instance::resolve(self.tcx, self.param_env, def_id, substs)?;
+ let instance = Instance::resolve(self.lcx.tcx, self.param_env, def_id, substs)?;
let gid = GlobalId {
instance,
promoted: None,
};
- let result = self.tcx.const_eval(self.param_env.and(gid)).ok()?;
- let ret = miri_to_const(self.tcx, &result);
- if ret.is_some() {
+ let result = self.lcx.tcx.const_eval(self.param_env.and(gid)).ok()?;
+ let result = miri_to_const(&result);
+ if result.is_some() {
self.needed_resolution = true;
}
- return ret;
+ result
},
- _ => {},
+ // FIXME: cover all usable cases.
+ _ => None,
}
- None
}
- /// A block can only yield a constant if it only has one constant expression
+ /// A block can only yield a constant if it only has one constant expression.
fn block(&mut self, block: &Block) -> Option<Constant> {
if block.stmts.is_empty() {
block.expr.as_ref().and_then(|b| self.expr(b))
}
}
- fn ifthenelse(&mut self, cond: &Expr, then: &P<Expr>, otherwise: &Option<P<Expr>>) -> Option<Constant> {
+ fn ifthenelse(&mut self, cond: &Expr, then: &Expr, otherwise: Option<&Expr>) -> Option<Constant> {
if let Some(Constant::Bool(b)) = self.expr(cond) {
if b {
- self.expr(&**then)
+ self.expr(&*then)
} else {
otherwise.as_ref().and_then(|expr| self.expr(expr))
}
match (l, r) {
(Constant::Int(l), Some(Constant::Int(r))) => match self.tables.expr_ty(left).sty {
ty::Int(ity) => {
- let l = sext(self.tcx, l, ity);
- let r = sext(self.tcx, r, ity);
- let zext = |n: i128| Constant::Int(unsext(self.tcx, n, ity));
+ let l = sext(self.lcx.tcx, l, ity);
+ let r = sext(self.lcx.tcx, r, ity);
+ let zext = |n: i128| Constant::Int(unsext(self.lcx.tcx, n, ity));
match op.node {
BinOpKind::Add => l.checked_add(r).map(zext),
BinOpKind::Sub => l.checked_sub(r).map(zext),
}
}
-pub fn miri_to_const<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, result: &ty::Const<'tcx>) -> Option<Constant> {
+pub fn miri_to_const(result: &ty::Const<'_>) -> Option<Constant> {
use rustc::mir::interpret::{ConstValue, Scalar};
match result.val {
- ConstValue::Scalar(Scalar::Bits { bits: b, .. }) => match result.ty.sty {
- ty::Bool => Some(Constant::Bool(b == 1)),
- ty::Uint(_) | ty::Int(_) => Some(Constant::Int(b)),
+ ConstValue::Scalar(Scalar::Raw { data: d, .. }) => match result.ty.sty {
+ ty::Bool => Some(Constant::Bool(d == 1)),
+ ty::Uint(_) | ty::Int(_) => Some(Constant::Int(d)),
ty::Float(FloatTy::F32) => Some(Constant::F32(f32::from_bits(
- b.try_into().expect("invalid f32 bit representation"),
+ d.try_into().expect("invalid f32 bit representation"),
))),
ty::Float(FloatTy::F64) => Some(Constant::F64(f64::from_bits(
- b.try_into().expect("invalid f64 bit representation"),
+ d.try_into().expect("invalid f64 bit representation"),
))),
- // FIXME: implement other conversion
+ ty::RawPtr(type_and_mut) => {
+ if let ty::Uint(_) = type_and_mut.ty.sty {
+ return Some(Constant::RawPtr(d));
+ }
+ None
+ },
+ // FIXME: implement other conversions.
_ => None,
},
- ConstValue::Slice(Scalar::Ptr(ptr), n) => match result.ty.sty {
+ ConstValue::Slice { data, start, end } => match result.ty.sty {
ty::Ref(_, tam, _) => match tam.sty {
- ty::Str => {
- let alloc = tcx.alloc_map.lock().unwrap_memory(ptr.alloc_id);
- let offset = ptr.offset.bytes().try_into().expect("too-large pointer offset");
- let n = usize::try_from(n).unwrap();
- String::from_utf8(alloc.bytes[offset..(offset + n)].to_owned())
- .ok()
- .map(Constant::Str)
- },
+ ty::Str => String::from_utf8(
+ data.inspect_with_undef_and_ptr_outside_interpreter(start..end)
+ .to_owned(),
+ )
+ .ok()
+ .map(Constant::Str),
_ => None,
},
_ => None,
},
- // FIXME: implement other conversions
+ // FIXME: implement other conversions.
_ => None,
}
}