mirror of
https://github.com/rust-lang/rust
synced 2024-09-15 22:50:55 +00:00
rustc::middle::const_eval : add overflow-checking for {+, -, *}.
The overflow-checking attempts to accommodate early evaluation where we do not have type information yet. Also, add fixme note about something that has been bothering me.
This commit is contained in:
parent
2e93e386fd
commit
b02f7d2fac
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@ -13,6 +13,8 @@
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pub use self::const_val::*;
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use self::ErrKind::*;
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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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@ -27,6 +29,7 @@
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use std::borrow::{Cow, IntoCow};
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use std::num::wrapping::OverflowingOps;
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use std::num::ToPrimitive;
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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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@ -234,6 +237,7 @@ pub enum ErrKind {
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NotOnStruct,
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NotOnTuple,
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NegateWithOverflow(i64),
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AddiWithOverflow(i64, i64),
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SubiWithOverflow(i64, i64),
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MuliWithOverflow(i64, i64),
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@ -244,6 +248,8 @@ pub enum ErrKind {
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DivideWithOverflow,
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ModuloByZero,
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ModuloWithOverflow,
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ShiftLeftWithOverflow,
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ShiftRightWithOverflow,
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MissingStructField,
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NonConstPath,
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ExpectedConstTuple,
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@ -257,6 +263,7 @@ pub enum ErrKind {
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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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@ -275,6 +282,7 @@ pub fn description(&self) -> Cow<str> {
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NotOnStruct => "not on struct".into_cow(),
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NotOnTuple => "not on tuple".into_cow(),
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NegateWithOverflow(..) => "attempted to negate with overflow".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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@ -285,6 +293,8 @@ pub fn description(&self) -> Cow<str> {
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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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ShiftLeftWithOverflow => "attempted left shift with overflow".into_cow(),
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ShiftRightWithOverflow => "attempted right shift 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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@ -297,57 +307,294 @@ pub fn description(&self) -> Cow<str> {
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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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pub type EvalResult = Result<const_val, ConstEvalErr>;
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pub type CastResult = Result<const_val, ErrKind>;
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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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#[derive(Copy, Clone, PartialEq, Debug)]
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pub enum IntTy { I8, I16, I32, I64 }
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#[derive(Copy, Clone, PartialEq, Debug)]
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pub enum UintTy { U8, U16, U32, U64 }
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impl IntTy {
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pub fn from(tcx: &ty::ctxt, t: ast::IntTy) -> IntTy {
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let t = if let ast::TyIs = t {
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tcx.sess.target.int_type
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} else {
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t
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};
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match t {
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ast::TyIs => unreachable!(),
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ast::TyI8 => IntTy::I8,
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ast::TyI16 => IntTy::I16,
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ast::TyI32 => IntTy::I32,
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ast::TyI64 => IntTy::I64,
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}
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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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impl UintTy {
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pub fn from(tcx: &ty::ctxt, t: ast::UintTy) -> UintTy {
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let t = if let ast::TyUs = t {
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tcx.sess.target.uint_type
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} else {
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t
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};
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match t {
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ast::TyUs => unreachable!(),
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ast::TyU8 => UintTy::U8,
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ast::TyU16 => UintTy::U16,
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ast::TyU32 => UintTy::U32,
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ast::TyU64 => UintTy::U64,
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}
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}
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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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macro_rules! signal {
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($e:expr, $exn:expr) => {
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return Err(ConstEvalErr { span: $e.span, kind: $exn })
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}
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}
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// The const_{int,uint}_checked_{neg,add,sub,mul,div,shl,shr} family
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// of functions catch and signal overflow errors during constant
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// evaluation.
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//
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// They all take the operator's arguments (`a` and `b` if binary), the
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// overall expression (`e`) and, if available, whole expression's
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// concrete type (`opt_ety`).
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//
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// If the whole expression's concrete type is None, then this is a
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// constant evaluation happening before type check (e.g. in the check
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// to confirm that a pattern range's left-side is not greater than its
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// right-side). We do not do arithmetic modulo the type's bitwidth in
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// such a case; we just do 64-bit arithmetic and assume that later
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// passes will do it again with the type information, and thus do the
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// overflow checks then.
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pub fn const_int_checked_neg<'a>(
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a: i64, e: &'a Expr, opt_ety: Option<IntTy>) -> EvalResult {
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let (min,max) = match opt_ety {
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// (-i8::MIN is itself not an i8, etc, but this is an easy way
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// to allow literals to pass the check. Of course that does
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// not work for i64::MIN.)
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Some(IntTy::I8) => (-(i8::MAX as i64), -(i8::MIN as i64)),
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Some(IntTy::I16) => (-(i16::MAX as i64), -(i16::MIN as i64)),
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Some(IntTy::I32) => (-(i32::MAX as i64), -(i32::MIN as i64)),
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None | Some(IntTy::I64) => (-i64::MAX, -(i64::MIN+1)),
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};
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let oflo = a < min || a > max;
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if oflo {
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signal!(e, NegateWithOverflow(a));
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} else {
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Ok(const_int(-a))
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}
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}
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pub fn const_uint_checked_neg<'a>(
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a: u64, _e: &'a Expr, _opt_ety: Option<UintTy>) -> EvalResult {
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// This always succeeds, and by definition, returns `(!a)+1`.
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Ok(const_uint(-a))
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}
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macro_rules! overflow_checking_body {
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($a:ident, $b:ident, $ety:ident, $overflowing_op:ident,
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lhs: $to_8_lhs:ident $to_16_lhs:ident $to_32_lhs:ident,
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rhs: $to_8_rhs:ident $to_16_rhs:ident $to_32_rhs:ident $to_64_rhs:ident,
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$EnumTy:ident $T8: ident $T16: ident $T32: ident $T64: ident,
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$result_type: ident) => { {
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let (a,b,opt_ety) = ($a,$b,$ety);
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match opt_ety {
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Some($EnumTy::$T8) => match (a.$to_8_lhs(), b.$to_8_rhs()) {
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(Some(a), Some(b)) => {
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let (a, oflo) = a.$overflowing_op(b);
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(a as $result_type, oflo)
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}
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(None, _) | (_, None) => (0, true)
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},
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Some($EnumTy::$T16) => match (a.$to_16_lhs(), b.$to_16_rhs()) {
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(Some(a), Some(b)) => {
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let (a, oflo) = a.$overflowing_op(b);
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(a as $result_type, oflo)
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}
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(None, _) | (_, None) => (0, true)
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},
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Some($EnumTy::$T32) => match (a.$to_32_lhs(), b.$to_32_rhs()) {
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(Some(a), Some(b)) => {
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let (a, oflo) = a.$overflowing_op(b);
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(a as $result_type, oflo)
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}
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(None, _) | (_, None) => (0, true)
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},
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None | Some($EnumTy::$T64) => match b.$to_64_rhs() {
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Some(b) => a.$overflowing_op(b),
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None => (0, true),
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}
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}
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} }
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}
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macro_rules! int_arith_body {
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($a:ident, $b:ident, $ety:ident, $overflowing_op:ident) => {
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overflow_checking_body!(
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$a, $b, $ety, $overflowing_op,
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lhs: to_i8 to_i16 to_i32,
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rhs: to_i8 to_i16 to_i32 to_i64, IntTy I8 I16 I32 I64, i64)
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}
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}
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macro_rules! uint_arith_body {
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($a:ident, $b:ident, $ety:ident, $overflowing_op:ident) => {
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overflow_checking_body!(
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$a, $b, $ety, $overflowing_op,
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lhs: to_u8 to_u16 to_u32,
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rhs: to_u8 to_u16 to_u32 to_u64, UintTy U8 U16 U32 U64, u64)
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}
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}
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macro_rules! int_shift_body {
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($a:ident, $b:ident, $ety:ident, $overflowing_op:ident) => {
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overflow_checking_body!(
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$a, $b, $ety, $overflowing_op,
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lhs: to_i8 to_i16 to_i32,
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rhs: to_u32 to_u32 to_u32 to_u32, IntTy I8 I16 I32 I64, i64)
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}
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}
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macro_rules! uint_shift_body {
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($a:ident, $b:ident, $ety:ident, $overflowing_op:ident) => {
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overflow_checking_body!(
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$a, $b, $ety, $overflowing_op,
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lhs: to_u8 to_u16 to_u32,
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rhs: to_u32 to_u32 to_u32 to_u32, UintTy U8 U16 U32 U64, u64)
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}
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}
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macro_rules! pub_fn_checked_op {
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{$fn_name:ident ($a:ident : $a_ty:ty, $b:ident : $b_ty:ty,.. $WhichTy:ident) {
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$ret_oflo_body:ident $overflowing_op:ident
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$const_ty:ident $signal_exn:expr
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}} => {
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pub fn $fn_name<'a>($a: $a_ty,
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$b: $b_ty,
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e: &'a Expr,
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opt_ety: Option<$WhichTy>) -> EvalResult {
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let (ret, oflo) = $ret_oflo_body!($a, $b, opt_ety, $overflowing_op);
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if !oflo { Ok($const_ty(ret)) } else { signal!(e, $signal_exn) }
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}
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}
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}
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pub_fn_checked_op!{ const_int_checked_add(a: i64, b: i64,.. IntTy) {
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int_arith_body overflowing_add const_int AddiWithOverflow(a, b)
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}}
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pub_fn_checked_op!{ const_int_checked_sub(a: i64, b: i64,.. IntTy) {
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int_arith_body overflowing_sub const_int SubiWithOverflow(a, b)
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}}
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pub_fn_checked_op!{ const_int_checked_mul(a: i64, b: i64,.. IntTy) {
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int_arith_body overflowing_mul const_int MuliWithOverflow(a, b)
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}}
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pub fn const_int_checked_div<'a>(
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a: i64, b: i64, e: &'a Expr, opt_ety: Option<IntTy>) -> EvalResult {
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if b == 0 { signal!(e, DivideByZero); }
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let (ret, oflo) = int_arith_body!(a, b, opt_ety, overflowing_div);
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if !oflo { Ok(const_int(ret)) } else { signal!(e, DivideWithOverflow) }
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}
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pub fn const_int_checked_rem<'a>(
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a: i64, b: i64, e: &'a Expr, opt_ety: Option<IntTy>) -> EvalResult {
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if b == 0 { signal!(e, ModuloByZero); }
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let (ret, oflo) = int_arith_body!(a, b, opt_ety, overflowing_rem);
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if !oflo { Ok(const_int(ret)) } else { signal!(e, ModuloWithOverflow) }
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}
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pub_fn_checked_op!{ const_int_checked_shl(a: i64, b: i64,.. IntTy) {
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int_shift_body overflowing_shl const_int ShiftLeftWithOverflow
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}}
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pub_fn_checked_op!{ const_int_checked_shl_via_uint(a: i64, b: u64,.. IntTy) {
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int_shift_body overflowing_shl const_int ShiftLeftWithOverflow
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}}
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pub_fn_checked_op!{ const_int_checked_shr(a: i64, b: i64,.. IntTy) {
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int_shift_body overflowing_shr const_int ShiftRightWithOverflow
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}}
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pub_fn_checked_op!{ const_int_checked_shr_via_uint(a: i64, b: u64,.. IntTy) {
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int_shift_body overflowing_shr const_int ShiftRightWithOverflow
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}}
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pub_fn_checked_op!{ const_uint_checked_add(a: u64, b: u64,.. UintTy) {
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uint_arith_body overflowing_add const_uint AdduWithOverflow(a, b)
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}}
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pub_fn_checked_op!{ const_uint_checked_sub(a: u64, b: u64,.. UintTy) {
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uint_arith_body overflowing_sub const_uint SubuWithOverflow(a, b)
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}}
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pub_fn_checked_op!{ const_uint_checked_mul(a: u64, b: u64,.. UintTy) {
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uint_arith_body overflowing_mul const_uint MuluWithOverflow(a, b)
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}}
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pub fn const_uint_checked_div<'a>(
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a: u64, b: u64, e: &'a Expr, opt_ety: Option<UintTy>) -> EvalResult {
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if b == 0 { signal!(e, DivideByZero); }
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let (ret, oflo) = uint_arith_body!(a, b, opt_ety, overflowing_div);
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if !oflo { Ok(const_uint(ret)) } else { signal!(e, DivideWithOverflow) }
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}
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pub fn const_uint_checked_rem<'a>(
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a: u64, b: u64, e: &'a Expr, opt_ety: Option<UintTy>) -> EvalResult {
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if b == 0 { signal!(e, ModuloByZero); }
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let (ret, oflo) = uint_arith_body!(a, b, opt_ety, overflowing_rem);
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if !oflo { Ok(const_uint(ret)) } else { signal!(e, ModuloWithOverflow) }
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}
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pub_fn_checked_op!{ const_uint_checked_shl(a: u64, b: u64,.. UintTy) {
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uint_shift_body overflowing_shl const_uint ShiftLeftWithOverflow
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}}
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pub_fn_checked_op!{ const_uint_checked_shl_via_int(a: u64, b: i64,.. UintTy) {
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uint_shift_body overflowing_shl const_uint ShiftLeftWithOverflow
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}}
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pub_fn_checked_op!{ const_uint_checked_shr(a: u64, b: u64,.. UintTy) {
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uint_shift_body overflowing_shr const_uint ShiftRightWithOverflow
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}}
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pub_fn_checked_op!{ const_uint_checked_shr_via_int(a: u64, b: i64,.. UintTy) {
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uint_shift_body overflowing_shr const_uint ShiftRightWithOverflow
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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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ty_hint: Option<Ty<'tcx>>) -> EvalResult {
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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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// If type of expression itself is int or uint, normalize in these
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// bindings so that isize/usize is mapped to a type with an
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// inherently known bitwidth.
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let expr_int_type = ety.and_then(|ty| {
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if let ty::ty_int(t) = ty.sty {
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Some(IntTy::from(tcx, t)) } else { None }
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});
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let expr_uint_type = ety.and_then(|ty| {
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if let ty::ty_uint(t) = ty.sty {
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Some(UintTy::from(tcx, t)) } else { None }
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});
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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),
|
||||
const_int(i) => const_int(-i),
|
||||
const_uint(i) => const_uint(-i),
|
||||
const_int(n) => try!(const_int_checked_neg(n, e, expr_int_type)),
|
||||
const_uint(n) => try!(const_uint_checked_neg(n, e, expr_uint_type)),
|
||||
const_str(_) => signal!(e, NegateOnString),
|
||||
const_bool(_) => signal!(e, NegateOnBoolean),
|
||||
const_binary(_) => signal!(e, NegateOnBinary),
|
||||
|
@ -391,51 +638,17 @@ fn fromb(b: bool) -> const_val { const_int(b as i64) }
|
|||
}
|
||||
}
|
||||
(const_int(a), const_int(b)) => {
|
||||
let is_a_min_value = || {
|
||||
let int_ty = match ty::expr_ty_opt(tcx, e).map(|ty| &ty.sty) {
|
||||
Some(&ty::ty_int(int_ty)) => int_ty,
|
||||
_ => return false
|
||||
};
|
||||
let int_ty = if let ast::TyIs = int_ty {
|
||||
tcx.sess.target.int_type
|
||||
} else {
|
||||
int_ty
|
||||
};
|
||||
match int_ty {
|
||||
ast::TyI8 => (a as i8) == i8::MIN,
|
||||
ast::TyI16 => (a as i16) == i16::MIN,
|
||||
ast::TyI32 => (a as i32) == i32::MIN,
|
||||
ast::TyI64 => (a as i64) == i64::MIN,
|
||||
ast::TyIs => unreachable!()
|
||||
}
|
||||
};
|
||||
match op.node {
|
||||
ast::BiAdd => try!(checked_add_int(e, a, b)),
|
||||
ast::BiSub => try!(checked_sub_int(e, a, b)),
|
||||
ast::BiMul => try!(checked_mul_int(e, a, b)),
|
||||
ast::BiDiv => {
|
||||
if b == 0 {
|
||||
signal!(e, DivideByZero);
|
||||
} else if b == -1 && is_a_min_value() {
|
||||
signal!(e, DivideWithOverflow);
|
||||
} else {
|
||||
const_int(a / b)
|
||||
}
|
||||
}
|
||||
ast::BiRem => {
|
||||
if b == 0 {
|
||||
signal!(e, ModuloByZero)
|
||||
} else if b == -1 && is_a_min_value() {
|
||||
signal!(e, ModuloWithOverflow)
|
||||
} else {
|
||||
const_int(a % b)
|
||||
}
|
||||
}
|
||||
ast::BiAdd => try!(const_int_checked_add(a,b,e,expr_int_type)),
|
||||
ast::BiSub => try!(const_int_checked_sub(a,b,e,expr_int_type)),
|
||||
ast::BiMul => try!(const_int_checked_mul(a,b,e,expr_int_type)),
|
||||
ast::BiDiv => try!(const_int_checked_div(a,b,e,expr_int_type)),
|
||||
ast::BiRem => try!(const_int_checked_rem(a,b,e,expr_int_type)),
|
||||
ast::BiAnd | ast::BiBitAnd => const_int(a & b),
|
||||
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::BiShl => try!(const_int_checked_shl(a,b,e,expr_int_type)),
|
||||
ast::BiShr => try!(const_int_checked_shr(a,b,e,expr_int_type)),
|
||||
ast::BiEq => fromb(a == b),
|
||||
ast::BiLt => fromb(a < b),
|
||||
ast::BiLe => fromb(a <= b),
|
||||
|
@ -446,18 +659,16 @@ fn fromb(b: bool) -> const_val { const_int(b as i64) }
|
|||
}
|
||||
(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::BiAdd => try!(const_uint_checked_add(a,b,e,expr_uint_type)),
|
||||
ast::BiSub => try!(const_uint_checked_sub(a,b,e,expr_uint_type)),
|
||||
ast::BiMul => try!(const_uint_checked_mul(a,b,e,expr_uint_type)),
|
||||
ast::BiDiv => try!(const_uint_checked_div(a,b,e,expr_uint_type)),
|
||||
ast::BiRem => try!(const_uint_checked_rem(a,b,e,expr_uint_type)),
|
||||
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::BiShl => try!(const_uint_checked_shl(a,b,e,expr_uint_type)),
|
||||
ast::BiShr => try!(const_uint_checked_shr(a,b,e,expr_uint_type)),
|
||||
ast::BiEq => fromb(a == b),
|
||||
ast::BiLt => fromb(a < b),
|
||||
ast::BiLe => fromb(a <= b),
|
||||
|
@ -469,15 +680,15 @@ fn fromb(b: bool) -> const_val { const_int(b as i64) }
|
|||
// 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),
|
||||
ast::BiShl => try!(const_int_checked_shl_via_uint(a,b,e,expr_int_type)),
|
||||
ast::BiShr => try!(const_int_checked_shr_via_uint(a,b,e,expr_int_type)),
|
||||
_ => 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),
|
||||
ast::BiShl => try!(const_uint_checked_shl_via_int(a,b,e,expr_uint_type)),
|
||||
ast::BiShr => try!(const_uint_checked_shr_via_int(a,b,e,expr_uint_type)),
|
||||
_ => signal!(e, InvalidOpForUintInt(op.node)),
|
||||
}
|
||||
}
|
||||
|
@ -506,7 +717,12 @@ fn fromb(b: bool) -> const_val { const_int(b as i64) }
|
|||
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.
|
||||
//
|
||||
// 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.
|
||||
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) {
|
||||
|
@ -607,7 +823,7 @@ fn fromb(b: bool) -> const_val { const_int(b as i64) }
|
|||
Ok(result)
|
||||
}
|
||||
|
||||
fn cast_const<'tcx>(tcx: &ty::ctxt<'tcx>, val: const_val, ty: Ty) -> Result<const_val, ErrKind> {
|
||||
fn cast_const<'tcx>(tcx: &ty::ctxt<'tcx>, val: const_val, ty: Ty) -> CastResult {
|
||||
macro_rules! convert_val {
|
||||
($intermediate_ty:ty, $const_type:ident, $target_ty:ty) => {
|
||||
match val {
|
||||
|
|
Loading…
Reference in a new issue