diff --git a/compiler/rustc_const_eval/src/interpret/machine.rs b/compiler/rustc_const_eval/src/interpret/machine.rs index 761ab81e22842..d30bd6c70138a 100644 --- a/compiler/rustc_const_eval/src/interpret/machine.rs +++ b/compiler/rustc_const_eval/src/interpret/machine.rs @@ -280,6 +280,9 @@ pub trait Machine<'tcx>: Sized { Ok(()) } + /// Determines the result of a `NullaryOp::UbChecks` invocation. + fn ub_checks(_ecx: &InterpCx<'tcx, Self>) -> InterpResult<'tcx, bool>; + /// Called when the interpreter encounters a `StatementKind::ConstEvalCounter` instruction. /// You can use this to detect long or endlessly running programs. #[inline] @@ -627,6 +630,13 @@ pub macro compile_time_machine(<$tcx: lifetime>) { match fn_val {} } + #[inline(always)] + fn ub_checks(_ecx: &InterpCx<$tcx, Self>) -> InterpResult<$tcx, bool> { + // We can't look at `tcx.sess` here as that can differ across crates, which can lead to + // unsound differences in evaluating the same constant at different instantiation sites. + Ok(true) + } + #[inline(always)] fn adjust_global_allocation<'b>( _ecx: &InterpCx<$tcx, Self>, diff --git a/compiler/rustc_const_eval/src/interpret/operator.rs b/compiler/rustc_const_eval/src/interpret/operator.rs index 2f860f9f942b2..e9ba12dbcc4ea 100644 --- a/compiler/rustc_const_eval/src/interpret/operator.rs +++ b/compiler/rustc_const_eval/src/interpret/operator.rs @@ -512,7 +512,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> { self.tcx.offset_of_subfield(self.param_env, layout, fields.iter()).bytes(); ImmTy::from_uint(val, usize_layout()) } - UbChecks => ImmTy::from_bool(self.tcx.sess.ub_checks(), *self.tcx), + UbChecks => ImmTy::from_bool(M::ub_checks(self)?, *self.tcx), }) } } diff --git a/src/tools/miri/src/machine.rs b/src/tools/miri/src/machine.rs index a7493d48d6a2d..f97b716e0b806 100644 --- a/src/tools/miri/src/machine.rs +++ b/src/tools/miri/src/machine.rs @@ -1060,6 +1060,10 @@ impl<'tcx> Machine<'tcx> for MiriMachine<'tcx> { ecx.generate_nan(inputs) } + fn ub_checks(ecx: &InterpCx<'tcx, Self>) -> InterpResult<'tcx, bool> { + Ok(ecx.tcx.sess.ub_checks()) + } + fn thread_local_static_pointer( ecx: &mut MiriInterpCx<'tcx>, def_id: DefId,