Merge from rustc

Author: RalfJung

src/machine.rs

@@ -22,8 +22,9 @@ use rustc_middle::{
 };
 use rustc_span::def_id::{CrateNum, DefId};
 use rustc_span::Symbol;
-use rustc_target::abi::Size;
+use rustc_target::abi::{Size, Align};
 use rustc_target::spec::abi::Abi;
+use rustc_const_eval::const_eval::CheckAlignment;
 
 use crate::{
     concurrency::{data_race, weak_memory},
@@ -781,15 +782,28 @@ impl<'mir, 'tcx> Machine<'mir, 'tcx> for MiriMachine<'mir, 'tcx> {
     const PANIC_ON_ALLOC_FAIL: bool = false;
 
     #[inline(always)]
-    fn enforce_alignment(ecx: &MiriInterpCx<'mir, 'tcx>) -> bool {
-        ecx.machine.check_alignment != AlignmentCheck::None
+    fn enforce_alignment(ecx: &MiriInterpCx<'mir, 'tcx>) -> CheckAlignment {
+        if ecx.machine.check_alignment == AlignmentCheck::None {
+            CheckAlignment::No
+        } else {
+            CheckAlignment::Error
+        }
     }
 
     #[inline(always)]
     fn use_addr_for_alignment_check(ecx: &MiriInterpCx<'mir, 'tcx>) -> bool {
         ecx.machine.check_alignment == AlignmentCheck::Int
     }
 
+    fn alignment_check_failed(
+        _ecx: &InterpCx<'mir, 'tcx, Self>,
+        has: Align,
+        required: Align,
+        _check: CheckAlignment,
+    ) -> InterpResult<'tcx, ()> {
+        throw_ub!(AlignmentCheckFailed { has, required })
+    }
+
     #[inline(always)]
     fn enforce_validity(ecx: &MiriInterpCx<'mir, 'tcx>) -> bool {
         ecx.machine.validate