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Prepare mir::Constant for ty::Const only supporting valtrees

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This commit is contained in:
Oli Scherer 2021-03-08 16:18:03 +00:00
parent 3ecde6f5db
commit 3127a9c60f
38 changed files with 369 additions and 153 deletions
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52
compiler/rustc_mir/src/transform/const_prop.rs
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@ -13,9 +13,9 @@ use rustc_middle::mir::visit::{
MutVisitor, MutatingUseContext, NonMutatingUseContext, PlaceContext, Visitor,
};
use rustc_middle::mir::{
AssertKind, BasicBlock, BinOp, Body, ClearCrossCrate, Constant, Local, LocalDecl, LocalKind,
Location, Operand, Place, Rvalue, SourceInfo, SourceScope, SourceScopeData, Statement,
StatementKind, Terminator, TerminatorKind, UnOp, RETURN_PLACE,
AssertKind, BasicBlock, BinOp, Body, ClearCrossCrate, Constant, ConstantSource, Local,
LocalDecl, LocalKind, Location, Operand, Place, Rvalue, SourceInfo, SourceScope,
SourceScopeData, Statement, StatementKind, Terminator, TerminatorKind, UnOp, RETURN_PLACE,
};
use rustc_middle::ty::layout::{HasTyCtxt, LayoutError, TyAndLayout};
use rustc_middle::ty::subst::{InternalSubsts, Subst};
@ -482,18 +482,21 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
return None;
}
match self.ecx.const_to_op(c.literal, None) {
match self.ecx.mir_const_to_op(&c.literal, None) {
Ok(op) => Some(op),
Err(error) => {
let tcx = self.ecx.tcx.at(c.span);
let err = ConstEvalErr::new(&self.ecx, error, Some(c.span));
if let Some(lint_root) = self.lint_root(source_info) {
let lint_only = match c.literal.val {
// Promoteds must lint and not error as the user didn't ask for them
ConstKind::Unevaluated(_, _, Some(_)) => true,
// Out of backwards compatibility we cannot report hard errors in unused
// generic functions using associated constants of the generic parameters.
_ => c.literal.needs_subst(),
let lint_only = match c.literal {
ConstantSource::Ty(ct) => match ct.val {
// Promoteds must lint and not error as the user didn't ask for them
ConstKind::Unevaluated(_, _, Some(_)) => true,
// Out of backwards compatibility we cannot report hard errors in unused
// generic functions using associated constants of the generic parameters.
_ => c.literal.needs_subst(),
},
ConstantSource::Val(_, ty) => ty.needs_subst(),
};
if lint_only {
// Out of backwards compatibility we cannot report hard errors in unused
@ -803,7 +806,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
Operand::Constant(Box::new(Constant {
span,
user_ty: None,
literal: ty::Const::from_scalar(self.tcx, scalar, ty),
literal: ty::Const::from_scalar(self.tcx, scalar, ty).into(),
}))
}
@ -814,9 +817,12 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
source_info: SourceInfo,
) {
if let Rvalue::Use(Operand::Constant(c)) = rval {
if !matches!(c.literal.val, ConstKind::Unevaluated(..)) {
trace!("skipping replace of Rvalue::Use({:?} because it is already a const", c);
return;
match c.literal {
ConstantSource::Ty(c) if matches!(c.val, ConstKind::Unevaluated(..)) => {}
_ => {
trace!("skipping replace of Rvalue::Use({:?} because it is already a const", c);
return;
}
}
}
@ -883,13 +889,17 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
*rval = Rvalue::Use(Operand::Constant(Box::new(Constant {
span: source_info.span,
user_ty: None,
literal: self.ecx.tcx.mk_const(ty::Const {
ty,
val: ty::ConstKind::Value(ConstValue::ByRef {
alloc,
offset: Size::ZERO,
}),
}),
literal: self
.ecx
.tcx
.mk_const(ty::Const {
ty,
val: ty::ConstKind::Value(ConstValue::ByRef {
alloc,
offset: Size::ZERO,
}),
})
.into(),
})));
}
}