diff options
Diffstat (limited to 'compiler/rustc_middle/src/ty/consts.rs')
| -rw-r--r-- | compiler/rustc_middle/src/ty/consts.rs | 254 |
1 files changed, 81 insertions, 173 deletions
diff --git a/compiler/rustc_middle/src/ty/consts.rs b/compiler/rustc_middle/src/ty/consts.rs index cce10417e..2518f0cf2 100644 --- a/compiler/rustc_middle/src/ty/consts.rs +++ b/compiler/rustc_middle/src/ty/consts.rs @@ -1,5 +1,5 @@ use crate::middle::resolve_bound_vars as rbv; -use crate::mir::interpret::{AllocId, ConstValue, LitToConstInput, Scalar}; +use crate::mir::interpret::{AllocId, ErrorHandled, LitToConstInput, Scalar}; use crate::ty::{self, GenericArgs, ParamEnv, ParamEnvAnd, Ty, TyCtxt, TypeVisitableExt}; use rustc_data_structures::intern::Interned; use rustc_error_messages::MultiSpan; @@ -14,9 +14,8 @@ mod valtree; pub use int::*; pub use kind::*; -use rustc_span::ErrorGuaranteed; +use rustc_span::Span; use rustc_span::DUMMY_SP; -use rustc_target::abi::Size; pub use valtree::*; use super::sty::ConstKind; @@ -36,16 +35,6 @@ pub struct ConstData<'tcx> { #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))] static_assert_size!(ConstData<'_>, 40); -enum EvalMode { - Typeck, - Mir, -} - -enum EvalResult<'tcx> { - ValTree(ty::ValTree<'tcx>), - ConstVal(ConstValue<'tcx>), -} - impl<'tcx> Const<'tcx> { #[inline] pub fn ty(self) -> Ty<'tcx> { @@ -165,7 +154,7 @@ impl<'tcx> Const<'tcx> { let ty = tcx.type_of(def).no_bound_vars().expect("const parameter types cannot be generic"); - match Self::try_eval_lit_or_param(tcx, ty, expr) { + match Self::try_from_lit_or_param(tcx, ty, expr) { Some(v) => v, None => ty::Const::new_unevaluated( tcx, @@ -179,7 +168,7 @@ impl<'tcx> Const<'tcx> { } #[instrument(skip(tcx), level = "debug")] - fn try_eval_lit_or_param( + fn try_from_lit_or_param( tcx: TyCtxt<'tcx>, ty: Ty<'tcx>, expr: &'tcx hir::Expr<'tcx>, @@ -254,14 +243,6 @@ impl<'tcx> Const<'tcx> { } } - /// Panics if self.kind != ty::ConstKind::Value - pub fn to_valtree(self) -> ty::ValTree<'tcx> { - match self.kind() { - ty::ConstKind::Value(valtree) => valtree, - _ => bug!("expected ConstKind::Value, got {:?}", self.kind()), - } - } - #[inline] /// Creates a constant with the given integer value and interns it. pub fn from_bits(tcx: TyCtxt<'tcx>, bits: u128, ty: ParamEnvAnd<'tcx, Ty<'tcx>>) -> Self { @@ -294,33 +275,83 @@ impl<'tcx> Const<'tcx> { Self::from_bits(tcx, n as u128, ParamEnv::empty().and(tcx.types.usize)) } - /// Attempts to convert to a `ValTree` - pub fn try_to_valtree(self) -> Option<ty::ValTree<'tcx>> { + /// Returns the evaluated constant + #[inline] + pub fn eval( + self, + tcx: TyCtxt<'tcx>, + param_env: ParamEnv<'tcx>, + span: Option<Span>, + ) -> Result<ValTree<'tcx>, ErrorHandled> { + assert!(!self.has_escaping_bound_vars(), "escaping vars in {self:?}"); match self.kind() { - ty::ConstKind::Value(valtree) => Some(valtree), - _ => None, + ConstKind::Unevaluated(unevaluated) => { + // FIXME(eddyb) maybe the `const_eval_*` methods should take + // `ty::ParamEnvAnd` instead of having them separate. + let (param_env, unevaluated) = unevaluated.prepare_for_eval(tcx, param_env); + // try to resolve e.g. associated constants to their definition on an impl, and then + // evaluate the const. + let c = tcx.const_eval_resolve_for_typeck(param_env, unevaluated, span)?; + Ok(c.expect("`ty::Const::eval` called on a non-valtree-compatible type")) + } + ConstKind::Value(val) => Ok(val), + ConstKind::Error(g) => Err(g.into()), + ConstKind::Param(_) + | ConstKind::Infer(_) + | ConstKind::Bound(_, _) + | ConstKind::Placeholder(_) + | ConstKind::Expr(_) => Err(ErrorHandled::TooGeneric(span.unwrap_or(DUMMY_SP))), } } + /// Normalizes the constant to a value or an error if possible. + #[inline] + pub fn normalize(self, tcx: TyCtxt<'tcx>, param_env: ParamEnv<'tcx>) -> Self { + match self.eval(tcx, param_env, None) { + Ok(val) => Self::new_value(tcx, val, self.ty()), + Err(ErrorHandled::Reported(r, _span)) => Self::new_error(tcx, r.into(), self.ty()), + Err(ErrorHandled::TooGeneric(_span)) => self, + } + } + + #[inline] + pub fn try_eval_scalar( + self, + tcx: TyCtxt<'tcx>, + param_env: ty::ParamEnv<'tcx>, + ) -> Option<Scalar> { + self.eval(tcx, param_env, None).ok()?.try_to_scalar() + } + #[inline] /// Attempts to evaluate the given constant to bits. Can fail to evaluate in the presence of /// generics (or erroneous code) or if the value can't be represented as bits (e.g. because it /// contains const generic parameters or pointers). - pub fn try_eval_bits( + pub fn try_eval_scalar_int( self, tcx: TyCtxt<'tcx>, param_env: ParamEnv<'tcx>, - ty: Ty<'tcx>, - ) -> Option<u128> { - assert_eq!(self.ty(), ty); - let size = tcx.layout_of(param_env.with_reveal_all_normalized(tcx).and(ty)).ok()?.size; + ) -> Option<ScalarInt> { + self.try_eval_scalar(tcx, param_env)?.try_to_int().ok() + } + + #[inline] + /// Attempts to evaluate the given constant to bits. Can fail to evaluate in the presence of + /// generics (or erroneous code) or if the value can't be represented as bits (e.g. because it + /// contains const generic parameters or pointers). + pub fn try_eval_bits(self, tcx: TyCtxt<'tcx>, param_env: ParamEnv<'tcx>) -> Option<u128> { + let int = self.try_eval_scalar_int(tcx, param_env)?; + let size = + tcx.layout_of(param_env.with_reveal_all_normalized(tcx).and(self.ty())).ok()?.size; // if `ty` does not depend on generic parameters, use an empty param_env - self.eval(tcx, param_env).try_to_bits(size) + int.to_bits(size).ok() } #[inline] - pub fn try_eval_bool(self, tcx: TyCtxt<'tcx>, param_env: ParamEnv<'tcx>) -> Option<bool> { - self.eval(tcx, param_env).try_to_bool() + /// Panics if the value cannot be evaluated or doesn't contain a valid integer of the given type. + pub fn eval_bits(self, tcx: TyCtxt<'tcx>, param_env: ParamEnv<'tcx>) -> u128 { + self.try_eval_bits(tcx, param_env) + .unwrap_or_else(|| bug!("expected bits of {:#?}, got {:#?}", self.ty(), self)) } #[inline] @@ -329,29 +360,12 @@ impl<'tcx> Const<'tcx> { tcx: TyCtxt<'tcx>, param_env: ParamEnv<'tcx>, ) -> Option<u64> { - self.eval(tcx, param_env).try_to_target_usize(tcx) - } - - #[inline] - /// Tries to evaluate the constant if it is `Unevaluated`. If that doesn't succeed, return the - /// unevaluated constant. - pub fn eval(self, tcx: TyCtxt<'tcx>, param_env: ParamEnv<'tcx>) -> Const<'tcx> { - if let Some(val) = self.try_eval_for_typeck(tcx, param_env) { - match val { - Ok(val) => ty::Const::new_value(tcx, val, self.ty()), - Err(guar) => ty::Const::new_error(tcx, guar, self.ty()), - } - } else { - // Either the constant isn't evaluatable or ValTree creation failed. - self - } + self.try_eval_scalar_int(tcx, param_env)?.try_to_target_usize(tcx).ok() } #[inline] - /// Panics if the value cannot be evaluated or doesn't contain a valid integer of the given type. - pub fn eval_bits(self, tcx: TyCtxt<'tcx>, param_env: ParamEnv<'tcx>, ty: Ty<'tcx>) -> u128 { - self.try_eval_bits(tcx, param_env, ty) - .unwrap_or_else(|| bug!("expected bits of {:#?}, got {:#?}", ty, self)) + pub fn try_eval_bool(self, tcx: TyCtxt<'tcx>, param_env: ParamEnv<'tcx>) -> Option<bool> { + self.try_eval_scalar_int(tcx, param_env)?.try_into().ok() } #[inline] @@ -361,136 +375,30 @@ impl<'tcx> Const<'tcx> { .unwrap_or_else(|| bug!("expected usize, got {:#?}", self)) } - #[inline] - /// Tries to evaluate the constant if it is `Unevaluated`. If that isn't possible or necessary - /// return `None`. - // FIXME(@lcnr): Completely rework the evaluation/normalization system for `ty::Const` once valtrees are merged. - pub fn try_eval_for_mir( - self, - tcx: TyCtxt<'tcx>, - param_env: ParamEnv<'tcx>, - ) -> Option<Result<ConstValue<'tcx>, ErrorGuaranteed>> { - match self.try_eval_inner(tcx, param_env, EvalMode::Mir) { - Some(Ok(EvalResult::ValTree(_))) => unreachable!(), - Some(Ok(EvalResult::ConstVal(v))) => Some(Ok(v)), - Some(Err(e)) => Some(Err(e)), - None => None, - } - } - - #[inline] - /// Tries to evaluate the constant if it is `Unevaluated`. If that isn't possible or necessary - /// return `None`. - // FIXME(@lcnr): Completely rework the evaluation/normalization system for `ty::Const` once valtrees are merged. - pub fn try_eval_for_typeck( - self, - tcx: TyCtxt<'tcx>, - param_env: ParamEnv<'tcx>, - ) -> Option<Result<ty::ValTree<'tcx>, ErrorGuaranteed>> { - match self.try_eval_inner(tcx, param_env, EvalMode::Typeck) { - Some(Ok(EvalResult::ValTree(v))) => Some(Ok(v)), - Some(Ok(EvalResult::ConstVal(_))) => unreachable!(), - Some(Err(e)) => Some(Err(e)), - None => None, + /// Panics if self.kind != ty::ConstKind::Value + pub fn to_valtree(self) -> ty::ValTree<'tcx> { + match self.kind() { + ty::ConstKind::Value(valtree) => valtree, + _ => bug!("expected ConstKind::Value, got {:?}", self.kind()), } } - #[inline] - fn try_eval_inner( - self, - tcx: TyCtxt<'tcx>, - param_env: ParamEnv<'tcx>, - eval_mode: EvalMode, - ) -> Option<Result<EvalResult<'tcx>, ErrorGuaranteed>> { - assert!(!self.has_escaping_bound_vars(), "escaping vars in {self:?}"); - if let ConstKind::Unevaluated(unevaluated) = self.kind() { - use crate::mir::interpret::ErrorHandled; - - // HACK(eddyb) this erases lifetimes even though `const_eval_resolve` - // also does later, but we want to do it before checking for - // inference variables. - // Note that we erase regions *before* calling `with_reveal_all_normalized`, - // so that we don't try to invoke this query with - // any region variables. - - // HACK(eddyb) when the query key would contain inference variables, - // attempt using identity args and `ParamEnv` instead, that will succeed - // when the expression doesn't depend on any parameters. - // FIXME(eddyb, skinny121) pass `InferCtxt` into here when it's available, so that - // we can call `infcx.const_eval_resolve` which handles inference variables. - let param_env_and = if (param_env, unevaluated).has_non_region_infer() { - tcx.param_env(unevaluated.def).and(ty::UnevaluatedConst { - def: unevaluated.def, - args: GenericArgs::identity_for_item(tcx, unevaluated.def), - }) - } else { - tcx.erase_regions(param_env) - .with_reveal_all_normalized(tcx) - .and(tcx.erase_regions(unevaluated)) - }; - - // FIXME(eddyb) maybe the `const_eval_*` methods should take - // `ty::ParamEnvAnd` instead of having them separate. - let (param_env, unevaluated) = param_env_and.into_parts(); - // try to resolve e.g. associated constants to their definition on an impl, and then - // evaluate the const. - match eval_mode { - EvalMode::Typeck => { - match tcx.const_eval_resolve_for_typeck(param_env, unevaluated, None) { - // NOTE(eddyb) `val` contains no lifetimes/types/consts, - // and we use the original type, so nothing from `args` - // (which may be identity args, see above), - // can leak through `val` into the const we return. - Ok(val) => Some(Ok(EvalResult::ValTree(val?))), - Err(ErrorHandled::TooGeneric) => None, - Err(ErrorHandled::Reported(e)) => Some(Err(e.into())), - } - } - EvalMode::Mir => { - match tcx.const_eval_resolve(param_env, unevaluated.expand(), None) { - // NOTE(eddyb) `val` contains no lifetimes/types/consts, - // and we use the original type, so nothing from `args` - // (which may be identity args, see above), - // can leak through `val` into the const we return. - Ok(val) => Some(Ok(EvalResult::ConstVal(val))), - Err(ErrorHandled::TooGeneric) => None, - Err(ErrorHandled::Reported(e)) => Some(Err(e.into())), - } - } - } - } else { - None + /// Attempts to convert to a `ValTree` + pub fn try_to_valtree(self) -> Option<ty::ValTree<'tcx>> { + match self.kind() { + ty::ConstKind::Value(valtree) => Some(valtree), + _ => None, } } #[inline] - pub fn try_to_value(self) -> Option<ty::ValTree<'tcx>> { - if let ConstKind::Value(val) = self.kind() { Some(val) } else { None } - } - - #[inline] pub fn try_to_scalar(self) -> Option<Scalar<AllocId>> { - self.try_to_value()?.try_to_scalar() - } - - #[inline] - pub fn try_to_scalar_int(self) -> Option<ScalarInt> { - self.try_to_value()?.try_to_scalar_int() - } - - #[inline] - pub fn try_to_bits(self, size: Size) -> Option<u128> { - self.try_to_scalar_int()?.to_bits(size).ok() - } - - #[inline] - pub fn try_to_bool(self) -> Option<bool> { - self.try_to_scalar_int()?.try_into().ok() + self.try_to_valtree()?.try_to_scalar() } #[inline] pub fn try_to_target_usize(self, tcx: TyCtxt<'tcx>) -> Option<u64> { - self.try_to_value()?.try_to_target_usize(tcx) + self.try_to_valtree()?.try_to_target_usize(tcx) } pub fn is_ct_infer(self) -> bool { |