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Do not call the const_eval query in mir interpretation except for caching of nulary intrinsics

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This commit is contained in:
Oliver Scherer 2020-08-10 12:40:14 +02:00
parent a6c60bbe5d
commit dd9702a059
4 changed files with 8 additions and 34 deletions
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2
compiler/rustc_mir/src/const_eval/machine.rs
View file

@ -51,7 +51,7 @@ impl<'mir, 'tcx> InterpCx<'mir, 'tcx, CompileTimeInterpreter<'mir, 'tcx>> {
let gid = GlobalId { instance, promoted: None };
let place = self.const_eval_raw(gid)?;
let place = self.const_eval(gid)?;
self.copy_op(place.into(), dest)?;

29
compiler/rustc_mir/src/interpret/eval_context.rs
View file

@ -20,7 +20,7 @@ use rustc_span::{Pos, Span};
use rustc_target::abi::{Align, HasDataLayout, LayoutOf, Size, TargetDataLayout};
use super::{
Immediate, MPlaceTy, Machine, MemPlace, MemPlaceMeta, Memory, OpTy, Operand, Place, PlaceTy,
Immediate, MPlaceTy, Machine, MemPlace, MemPlaceMeta, Memory, Operand, Place, PlaceTy,
ScalarMaybeUninit, StackPopJump,
};
use crate::transform::validate::equal_up_to_regions;
@ -875,32 +875,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
Ok(())
}
pub(super) fn const_eval(
&self,
gid: GlobalId<'tcx>,
ty: Ty<'tcx>,
) -> InterpResult<'tcx, OpTy<'tcx, M::PointerTag>> {
// For statics we pick `ParamEnv::reveal_all`, because statics don't have generics
// and thus don't care about the parameter environment. While we could just use
// `self.param_env`, that would mean we invoke the query to evaluate the static
// with different parameter environments, thus causing the static to be evaluated
// multiple times.
let param_env = if self.tcx.is_static(gid.instance.def_id()) {
ty::ParamEnv::reveal_all()
} else {
self.param_env
};
let val = self.tcx.const_eval_global_id(param_env, gid, Some(self.tcx.span))?;
// Even though `ecx.const_eval` is called from `const_to_op` we can never have a
// recursion deeper than one level, because the `tcx.const_eval` above is guaranteed to not
// return `ConstValue::Unevaluated`, which is the only way that `const_to_op` will call
// `ecx.const_eval`.
let const_ = ty::Const { val: ty::ConstKind::Value(val), ty };
self.const_to_op(&const_, None)
}
pub fn const_eval_raw(
pub fn const_eval(
&self,
gid: GlobalId<'tcx>,
) -> InterpResult<'tcx, MPlaceTy<'tcx, M::PointerTag>> {

5
compiler/rustc_mir/src/interpret/intrinsics.rs
View file

@ -152,7 +152,10 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
sym::type_name => self.tcx.mk_static_str(),
_ => bug!("already checked for nullary intrinsics"),
};
let val = self.const_eval(gid, ty)?;
let val =
self.tcx.const_eval_global_id(self.param_env, gid, Some(self.tcx.span))?;
let const_ = ty::Const { val: ty::ConstKind::Value(val), ty };
let val = self.const_to_op(&const_, None)?;
self.copy_op(val, dest)?;
}

6
compiler/rustc_mir/src/interpret/operand.rs
View file

@ -553,11 +553,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
ty::ConstKind::Error(_) => throw_inval!(TypeckError(ErrorReported)),
ty::ConstKind::Unevaluated(def, substs, promoted) => {
let instance = self.resolve(def.did, substs)?;
// We use `const_eval` here and `const_eval_raw` elsewhere in mir interpretation.
// The reason we use `const_eval` here is that there can never be a `ty::ConstKind`
// that directly mentions the initializer of a static. Statics are always encoded
// as constants with vaule `&STATIC`.
return Ok(self.const_eval(GlobalId { instance, promoted }, val.ty)?);
return Ok(self.const_eval(GlobalId { instance, promoted })?.into());
}
ty::ConstKind::Infer(..)
| ty::ConstKind::Bound(..)