bjoernager/rust
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found another place where we can eval() a const, and go through valtrees

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This commit is contained in:
Ralf Jung 2023-09-14 07:53:38 +02:00
parent 292d5bba86
commit 19fb2c7ccd
3 changed files with 14 additions and 39 deletions
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6
compiler/rustc_middle/src/mir/mod.rs
View file

@ -2297,7 +2297,11 @@ pub struct Constant<'tcx> {
#[derive(Clone, Copy, PartialEq, Eq, TyEncodable, TyDecodable, Hash, HashStable, Debug)]
#[derive(Lift, TypeFoldable, TypeVisitable)]
pub enum ConstantKind<'tcx> {
/// This constant came from the type system
/// This constant came from the type system.
///
/// Any way of turning `ty::Const` into `ConstValue` should go through `valtree_to_const_val`;
/// this ensures that we consistently produce "clean" values without data in the padding or
/// anything like that.
Ty(ty::Const<'tcx>),
/// An unevaluated mir constant which is not part of the type system.

5
compiler/rustc_middle/src/ty/consts/kind.rs
View file

@ -22,11 +22,6 @@ impl rustc_errors::IntoDiagnosticArg for UnevaluatedConst<'_> {
}
impl<'tcx> UnevaluatedConst<'tcx> {
#[inline]
pub fn expand(self) -> mir::UnevaluatedConst<'tcx> {
mir::UnevaluatedConst { def: self.def, args: self.args, promoted: None }
}
/// FIXME(RalfJung): I cannot explain what this does or why it makes sense, but not doing this
/// hurts performance.
#[inline]

28
compiler/rustc_monomorphize/src/collector.rs
View file

@ -749,39 +749,15 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirUsedCollector<'a, 'tcx> {
#[instrument(skip(self), level = "debug")]
fn visit_constant(&mut self, constant: &mir::Constant<'tcx>, location: Location) {
let literal = self.monomorphize(constant.literal);
let val = match literal {
mir::ConstantKind::Val(val, _) => val,
mir::ConstantKind::Ty(ct) => match ct.kind() {
ty::ConstKind::Value(val) => self.tcx.valtree_to_const_val((ct.ty(), val)),
ty::ConstKind::Unevaluated(ct) => {
debug!(?ct);
let param_env = ty::ParamEnv::reveal_all();
match self.tcx.const_eval_resolve(param_env, ct.expand(), None) {
// The `monomorphize` call should have evaluated that constant already.
Ok(val) => val,
let val = match literal.eval(self.tcx, param_env, None) {
Ok(v) => v,
Err(ErrorHandled::Reported(_)) => return,
Err(ErrorHandled::TooGeneric) => span_bug!(
self.body.source_info(location).span,
"collection encountered polymorphic constant: {:?}",
literal
),
}
}
_ => return,
},
mir::ConstantKind::Unevaluated(uv, _) => {
let param_env = ty::ParamEnv::reveal_all();
match self.tcx.const_eval_resolve(param_env, uv, None) {
// The `monomorphize` call should have evaluated that constant already.
Ok(val) => val,
Err(ErrorHandled::Reported(_)) => return,
Err(ErrorHandled::TooGeneric) => span_bug!(
self.body.source_info(location).span,
"collection encountered polymorphic constant: {:?}",
literal
),
}
}
};
collect_const_value(self.tcx, val, self.output);
MirVisitor::visit_ty(self, literal.ty(), TyContext::Location(location));