const-eval: make misalignment a hard error

3 files changed, 21 insertions, 44 deletions

diff --git a/compiler/rustc_const_eval/src/interpret/machine.rs b/compiler/rustc_const_eval/src/interpret/machine.rs
index aaa674a598f..73b2251c41e 100644
--- a/compiler/rustc_const_eval/src/interpret/machine.rs
+++ b/compiler/rustc_const_eval/src/interpret/machine.rs
@@ -11,11 +11,9 @@ use rustc_middle::mir;
 use rustc_middle::ty::layout::TyAndLayout;
 use rustc_middle::ty::{self, TyCtxt};
 use rustc_span::def_id::DefId;
-use rustc_target::abi::{Align, Size};
+use rustc_target::abi::Size;
 use rustc_target::spec::abi::Abi as CallAbi;
 
-use crate::const_eval::CheckAlignment;
-
 use super::{
     AllocBytes, AllocId, AllocRange, Allocation, ConstAllocation, FnArg, Frame, ImmTy, InterpCx,
     InterpResult, MPlaceTy, MemoryKind, OpTy, PlaceTy, Pointer, Provenance,
@@ -134,7 +132,7 @@ pub trait Machine<'mir, 'tcx: 'mir>: Sized {
     const POST_MONO_CHECKS: bool = true;
 
     /// Whether memory accesses should be alignment-checked.
-    fn enforce_alignment(ecx: &InterpCx<'mir, 'tcx, Self>) -> CheckAlignment;
+    fn enforce_alignment(ecx: &InterpCx<'mir, 'tcx, Self>) -> bool;
 
     /// Whether, when checking alignment, we should look at the actual address and thus support
     /// custom alignment logic based on whatever the integer address happens to be.
@@ -142,13 +140,6 @@ pub trait Machine<'mir, 'tcx: 'mir>: Sized {
     /// If this returns true, Provenance::OFFSET_IS_ADDR must be true.
     fn use_addr_for_alignment_check(ecx: &InterpCx<'mir, 'tcx, Self>) -> bool;
 
-    fn alignment_check_failed(
-        ecx: &InterpCx<'mir, 'tcx, Self>,
-        has: Align,
-        required: Align,
-        check: CheckAlignment,
-    ) -> InterpResult<'tcx, ()>;
-
     /// Whether to enforce the validity invariant for a specific layout.
     fn enforce_validity(ecx: &InterpCx<'mir, 'tcx, Self>, layout: TyAndLayout<'tcx>) -> bool;
 
diff --git a/compiler/rustc_const_eval/src/interpret/memory.rs b/compiler/rustc_const_eval/src/interpret/memory.rs
index 436c4d521a5..13b042cb86a 100644
--- a/compiler/rustc_const_eval/src/interpret/memory.rs
+++ b/compiler/rustc_const_eval/src/interpret/memory.rs
@@ -18,7 +18,6 @@ use rustc_middle::mir::display_allocation;
 use rustc_middle::ty::{self, Instance, ParamEnv, Ty, TyCtxt};
 use rustc_target::abi::{Align, HasDataLayout, Size};
 
-use crate::const_eval::CheckAlignment;
 use crate::fluent_generated as fluent;
 
 use super::{
@@ -373,8 +372,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         self.check_and_deref_ptr(
             ptr,
             size,
-            align,
-            M::enforce_alignment(self),
+            M::enforce_alignment(self).then_some(align),
             CheckInAllocMsg::MemoryAccessTest,
             |alloc_id, offset, prov| {
                 let (size, align) = self
@@ -395,17 +393,10 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         align: Align,
         msg: CheckInAllocMsg,
     ) -> InterpResult<'tcx> {
-        self.check_and_deref_ptr(
-            ptr,
-            size,
-            align,
-            CheckAlignment::Error,
-            msg,
-            |alloc_id, _, _| {
-                let (size, align) = self.get_live_alloc_size_and_align(alloc_id, msg)?;
-                Ok((size, align, ()))
-            },
-        )?;
+        self.check_and_deref_ptr(ptr, size, Some(align), msg, |alloc_id, _, _| {
+            let (size, align) = self.get_live_alloc_size_and_align(alloc_id, msg)?;
+            Ok((size, align, ()))
+        })?;
         Ok(())
     }
 
@@ -419,8 +410,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         &self,
         ptr: Pointer<Option<M::Provenance>>,
         size: Size,
-        align: Align,
-        check: CheckAlignment,
+        align: Option<Align>,
         msg: CheckInAllocMsg,
         alloc_size: impl FnOnce(
             AllocId,
@@ -436,8 +426,8 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                     throw_ub!(DanglingIntPointer(addr, msg));
                 }
                 // Must be aligned.
-                if check.should_check() {
-                    self.check_offset_align(addr, align, check)?;
+                if let Some(align) = align {
+                    self.check_offset_align(addr, align)?;
                 }
                 None
             }
@@ -460,16 +450,16 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 }
                 // Test align. Check this last; if both bounds and alignment are violated
                 // we want the error to be about the bounds.
-                if check.should_check() {
+                if let Some(align) = align {
                     if M::use_addr_for_alignment_check(self) {
                         // `use_addr_for_alignment_check` can only be true if `OFFSET_IS_ADDR` is true.
-                        self.check_offset_align(ptr.addr().bytes(), align, check)?;
+                        self.check_offset_align(ptr.addr().bytes(), align)?;
                     } else {
                         // Check allocation alignment and offset alignment.
                         if alloc_align.bytes() < align.bytes() {
-                            M::alignment_check_failed(self, alloc_align, align, check)?;
+                            throw_ub!(AlignmentCheckFailed { has: alloc_align, required: align });
                         }
-                        self.check_offset_align(offset.bytes(), align, check)?;
+                        self.check_offset_align(offset.bytes(), align)?;
                     }
                 }
 
@@ -480,18 +470,16 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         })
     }
 
-    fn check_offset_align(
-        &self,
-        offset: u64,
-        align: Align,
-        check: CheckAlignment,
-    ) -> InterpResult<'tcx> {
+    fn check_offset_align(&self, offset: u64, align: Align) -> InterpResult<'tcx> {
         if offset % align.bytes() == 0 {
             Ok(())
         } else {
             // The biggest power of two through which `offset` is divisible.
             let offset_pow2 = 1 << offset.trailing_zeros();
-            M::alignment_check_failed(self, Align::from_bytes(offset_pow2).unwrap(), align, check)
+            throw_ub!(AlignmentCheckFailed {
+                has: Align::from_bytes(offset_pow2).unwrap(),
+                required: align
+            });
         }
     }
 }
@@ -609,8 +597,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         let ptr_and_alloc = self.check_and_deref_ptr(
             ptr,
             size,
-            align,
-            M::enforce_alignment(self),
+            M::enforce_alignment(self).then_some(align),
             CheckInAllocMsg::MemoryAccessTest,
             |alloc_id, offset, prov| {
                 let alloc = self.get_alloc_raw(alloc_id)?;
diff --git a/compiler/rustc_const_eval/src/interpret/place.rs b/compiler/rustc_const_eval/src/interpret/place.rs
index 503004cbbe1..4617e1f0143 100644
--- a/compiler/rustc_const_eval/src/interpret/place.rs
+++ b/compiler/rustc_const_eval/src/interpret/place.rs
@@ -500,8 +500,7 @@ where
             .size_and_align_of_mplace(&mplace)?
             .unwrap_or((mplace.layout.size, mplace.layout.align.abi));
         // Due to packed places, only `mplace.align` matters.
-        let align =
-            if M::enforce_alignment(self).should_check() { mplace.align } else { Align::ONE };
+        let align = if M::enforce_alignment(self) { mplace.align } else { Align::ONE };
         self.check_ptr_access_align(mplace.ptr(), size, align, CheckInAllocMsg::DerefTest)?;
         Ok(())
     }