Auto merge of rust-lang#120594 - saethlin:delayed-debug-asserts, r=<try>

Toggle assert_unsafe_precondition in codegen instead of expansion

r? `@ghost`

rust-lang#120539 (comment)

compiler/rustc_codegen_cranelift/src/intrinsics/mod.rs

@@ -438,6 +438,14 @@ fn codegen_regular_intrinsic_call<'tcx>(
  fx.bcx.ins().trap(TrapCode::User(0));
  return;
  }
+ sym::debug_assertions => {
+ let bool_layout = fx.layout_of(fx.tcx.types.bool);
+ let val = CValue::by_val(
+ fx.bcx.ins().iconst(types::I8, fx.tcx.sess.opts.debug_assertions as i64),
+ bool_layout,
+ );
+ ret.write_cvalue(fx, val);
+ }
  sym::likely | sym::unlikely => {
  intrinsic_args!(fx, args => (a); intrinsic);
 

compiler/rustc_codegen_ssa/src/mir/intrinsic.rs

@@ -84,6 +84,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
  return;
  }
 
+ sym::debug_assertions => bx.const_bool(bx.tcx().sess.opts.debug_assertions),
  sym::va_start => bx.va_start(args[0].immediate()),
  sym::va_end => bx.va_end(args[0].immediate()),
  sym::size_of_val => {

compiler/rustc_const_eval/src/const_eval/machine.rs

@@ -536,6 +536,11 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for CompileTimeInterpreter<'mir,
  // (We know the value here in the machine of course, but this is the runtime of that code,
  // not the optimization stage.)
  sym::is_val_statically_known => ecx.write_scalar(Scalar::from_bool(false), dest)?,
+
+ sym::debug_assertions => {
+ ecx.write_scalar(Scalar::from_bool(ecx.tcx.sess.opts.debug_assertions), dest)?
+ }
+
  _ => {
  throw_unsup_format!(
  "intrinsic `{intrinsic_name}` is not supported at compile-time"

compiler/rustc_hir_analysis/src/check/intrinsic.rs

@@ -112,7 +112,8 @@ pub fn intrinsic_operation_unsafety(tcx: TyCtxt<'_>, intrinsic_id: DefId) -> hir
  | sym::forget
  | sym::black_box
  | sym::variant_count
- | sym::ptr_mask => hir::Unsafety::Normal,
+ | sym::ptr_mask
+ | sym::debug_assertions => hir::Unsafety::Normal,
  _ => hir::Unsafety::Unsafe,
  };
 
@@ -461,6 +462,8 @@ pub fn check_intrinsic_type(tcx: TyCtxt<'_>, it: &hir::ForeignItem<'_>) {
  (0, vec![Ty::new_imm_ptr(tcx, Ty::new_unit(tcx))], tcx.types.usize)
  }
 
+ sym::debug_assertions => (0, Vec::new(), tcx.types.bool),
+
  other => {
  tcx.dcx().emit_err(UnrecognizedIntrinsicFunction { span: it.span, name: other });
  return;

library/core/src/intrinsics.rs

@@ -2569,6 +2569,12 @@ extern "rust-intrinsic" {
  #[rustc_nounwind]
  #[cfg(not(bootstrap))]
  pub fn is_val_statically_known<T: Copy>(arg: T) -> bool;
+
+ #[rustc_const_unstable(feature = "delayed_debug_assertions", issue = "none")]
+ #[rustc_safe_intrinsic]
+ #[rustc_nounwind]
+ #[cfg(not(bootstrap))]
+ pub(crate) fn debug_assertions() -> bool;
 }
 
 // FIXME: Seems using `unstable` here completely ignores `rustc_allow_const_fn_unstable`
@@ -2604,10 +2610,18 @@ pub const unsafe fn is_val_statically_known<T: Copy>(_arg: T) -> bool {
 ///
 /// So in a sense it is UB if this macro is useful, but we expect callers of `unsafe fn` to make
 /// the occasional mistake, and this check should help them figure things out.
-#[allow_internal_unstable(const_eval_select)] // permit this to be called in stably-const fn
+#[allow_internal_unstable(const_eval_select, delayed_debug_assertions)] // permit this to be called in stably-const fn
 macro_rules! assert_unsafe_precondition {
  ($name:expr, $([$($tt:tt)*])?($($i:ident:$ty:ty),*$(,)?) => $e:expr $(,)?) => {
- if cfg!(debug_assertions) {
+ {
+ #[cfg(bootstrap)]
+ let should_check = cfg!(debug_assertions);
+
+ // Turn assertions off in Miri, but otherwise check in codegen
+ #[cfg(not(bootstrap))]
+ let should_check = !cfg!(miri) && ::core::intrinsics::debug_assertions();
+
+ if should_check {
  // allow non_snake_case to allow capturing const generics
  #[allow(non_snake_case)]
  #[inline(always)]
@@ -2625,6 +2639,7 @@ macro_rules! assert_unsafe_precondition {
 
  ::core::intrinsics::const_eval_select(($($i,)*), comptime, runtime);
  }
+ }
  };
 }
 pub(crate) use assert_unsafe_precondition;

library/core/src/ptr/mod.rs

@@ -1208,10 +1208,12 @@ pub const unsafe fn read<T>(src: *const T) -> T {
 
  // SAFETY: the caller must guarantee that `src` is valid for reads.
  unsafe {
+ /*
  assert_unsafe_precondition!(
  "ptr::read requires that the pointer argument is aligned and non-null",
  [T](src: *const T) => is_aligned_and_not_null(src)
  );
+ */
  crate::intrinsics::read_via_copy(src)
  }
 }
@@ -1408,10 +1410,12 @@ pub const unsafe fn write<T>(dst: *mut T, src: T) {
  // `dst` cannot overlap `src` because the caller has mutable access
  // to `dst` while `src` is owned by this function.
  unsafe {
+ /*
  assert_unsafe_precondition!(
  "ptr::write requires that the pointer argument is aligned and non-null",
  [T](dst: *mut T) => is_aligned_and_not_null(dst)
  );
+ */
  intrinsics::write_via_move(dst, src)
  }
 }

tests/mir-opt/dataflow-const-prop/default_boxed_slice.main.DataflowConstProp.32bit.panic-abort.diff

@@ -24,22 +24,28 @@
  debug ptr => _6;
  scope 11 (inlined NonNull::<[bool; 0]>::new_unchecked) {
  debug ptr => _6;
- let mut _8: *const [bool; 0];
- let mut _9: *mut [bool; 0];
+ let mut _9: *const [bool; 0];
  scope 12 {
- scope 13 (inlined NonNull::<T>::new_unchecked::runtime::<[bool; 0]>) {
- debug ptr => _9;
- scope 14 (inlined std::ptr::mut_ptr::<impl *mut [bool; 0]>::is_null) {
- debug self => _9;
- let mut _10: *mut u8;
- scope 15 {
- scope 16 (inlined std::ptr::mut_ptr::<impl *mut T>::is_null::runtime_impl) {
- debug ptr => _10;
- scope 17 (inlined std::ptr::mut_ptr::<impl *mut u8>::addr) {
- debug self => _10;
- scope 18 {
- scope 19 (inlined std::ptr::mut_ptr::<impl *mut u8>::cast::<()>) {
- debug self => _10;
+ let _8: bool;
+ scope 13 {
+ debug should_check => _8;
+ scope 14 (inlined NonNull::<T>::new_unchecked::runtime::<[bool; 0]>) {
+ debug ptr => _6;
+ let _10: !;
+ scope 15 (inlined std::ptr::mut_ptr::<impl *mut [bool; 0]>::is_null) {
+ debug self => _6;
+ let mut _11: *mut u8;
+ scope 16 {
+ scope 17 (inlined std::ptr::mut_ptr::<impl *mut T>::is_null::runtime_impl) {
+ debug ptr => _11;
+ let mut _12: usize;
+ scope 18 (inlined std::ptr::mut_ptr::<impl *mut u8>::addr) {
+ debug self => _11;
+ let mut _13: *mut ();
+ scope 19 {
+ scope 20 (inlined std::ptr::mut_ptr::<impl *mut u8>::cast::<()>) {
+ debug self => _11;
+ }
  }
  }
  }
@@ -66,6 +72,7 @@
  StorageLive(_1);
  StorageLive(_2);
  StorageLive(_3);
+ StorageLive(_10);
  StorageLive(_4);
  StorageLive(_5);
  StorageLive(_6);
@@ -75,10 +82,33 @@
  StorageDead(_7);
  StorageLive(_8);
  StorageLive(_9);
- StorageLive(_10);
- _8 = const {0x1 as *mut [bool; 0]} as *const [bool; 0] (PointerCoercion(MutToConstPointer));
- _5 = NonNull::<[bool; 0]> { pointer: _8 };
- StorageDead(_10);
+ _8 = intrinsics::debug_assertions() -> [return: bb2, unwind unreachable];
+ }
+
+ bb1: {
+ StorageDead(_1);
+ return;
+ }
+
+ bb2: {
+ switchInt(_8) -> [0: bb4, otherwise: bb3];
+ }
+
+ bb3: {
+ StorageLive(_11);
+ _11 = const {0x1 as *mut [bool; 0]} as *mut u8 (PtrToPtr);
+ StorageLive(_12);
+ StorageLive(_13);
+ _13 = _11 as *mut () (PtrToPtr);
+ _12 = move _13 as usize (Transmute);
+ StorageDead(_13);
+ StorageDead(_11);
+ switchInt(move _12) -> [0: bb5, otherwise: bb6];
+ }
+
+ bb4: {
+ _9 = const {0x1 as *mut [bool; 0]} as *const [bool; 0] (PointerCoercion(MutToConstPointer));
+ _5 = NonNull::<[bool; 0]> { pointer: _9 };
  StorageDead(_9);
  StorageDead(_8);
  StorageDead(_6);
@@ -87,16 +117,22 @@
  _3 = move _4 as std::ptr::Unique<[bool]> (PointerCoercion(Unsize));
  StorageDead(_4);
  _2 = Box::<[bool]>(_3, const std::alloc::Global);
+ StorageDead(_10);
  StorageDead(_3);
  _1 = A { foo: move _2 };
  StorageDead(_2);
  _0 = const ();
  drop(_1) -> [return: bb1, unwind unreachable];
  }
 
- bb1: {
- StorageDead(_1);
- return;
+ bb5: {
+ StorageDead(_12);
+ _10 = core::panicking::panic_nounwind(const "unsafe precondition(s) violated: NonNull::new_unchecked requires that the pointer is non-null") -> unwind unreachable;
+ }
+
+ bb6: {
+ StorageDead(_12);
+ goto -> bb4;
  }
  }
 

tests/mir-opt/dataflow-const-prop/default_boxed_slice.main.DataflowConstProp.32bit.panic-unwind.diff

@@ -24,22 +24,28 @@
  debug ptr => _6;
  scope 11 (inlined NonNull::<[bool; 0]>::new_unchecked) {
  debug ptr => _6;
- let mut _8: *const [bool; 0];
- let mut _9: *mut [bool; 0];
+ let mut _9: *const [bool; 0];
  scope 12 {
- scope 13 (inlined NonNull::<T>::new_unchecked::runtime::<[bool; 0]>) {
- debug ptr => _9;
- scope 14 (inlined std::ptr::mut_ptr::<impl *mut [bool; 0]>::is_null) {
- debug self => _9;
- let mut _10: *mut u8;
- scope 15 {
- scope 16 (inlined std::ptr::mut_ptr::<impl *mut T>::is_null::runtime_impl) {
- debug ptr => _10;
- scope 17 (inlined std::ptr::mut_ptr::<impl *mut u8>::addr) {
- debug self => _10;
- scope 18 {
- scope 19 (inlined std::ptr::mut_ptr::<impl *mut u8>::cast::<()>) {
- debug self => _10;
+ let _8: bool;
+ scope 13 {
+ debug should_check => _8;
+ scope 14 (inlined NonNull::<T>::new_unchecked::runtime::<[bool; 0]>) {
+ debug ptr => _6;
+ let _10: !;
+ scope 15 (inlined std::ptr::mut_ptr::<impl *mut [bool; 0]>::is_null) {
+ debug self => _6;
+ let mut _11: *mut u8;
+ scope 16 {
+ scope 17 (inlined std::ptr::mut_ptr::<impl *mut T>::is_null::runtime_impl) {
+ debug ptr => _11;
+ let mut _12: usize;
+ scope 18 (inlined std::ptr::mut_ptr::<impl *mut u8>::addr) {
+ debug self => _11;
+ let mut _13: *mut ();
+ scope 19 {
+ scope 20 (inlined std::ptr::mut_ptr::<impl *mut u8>::cast::<()>) {
+ debug self => _11;
+ }
  }
  }
  }
@@ -66,6 +72,7 @@
  StorageLive(_1);
  StorageLive(_2);
  StorageLive(_3);
+ StorageLive(_10);
  StorageLive(_4);
  StorageLive(_5);
  StorageLive(_6);
@@ -75,10 +82,37 @@
  StorageDead(_7);
  StorageLive(_8);
  StorageLive(_9);
- StorageLive(_10);
- _8 = const {0x1 as *mut [bool; 0]} as *const [bool; 0] (PointerCoercion(MutToConstPointer));
- _5 = NonNull::<[bool; 0]> { pointer: _8 };
- StorageDead(_10);
+ _8 = intrinsics::debug_assertions() -> [return: bb3, unwind unreachable];
+ }
+
+ bb1: {
+ StorageDead(_1);
+ return;
+ }
+
+ bb2 (cleanup): {
+ resume;
+ }
+
+ bb3: {
+ switchInt(_8) -> [0: bb5, otherwise: bb4];
+ }
+
+ bb4: {
+ StorageLive(_11);
+ _11 = const {0x1 as *mut [bool; 0]} as *mut u8 (PtrToPtr);
+ StorageLive(_12);
+ StorageLive(_13);
+ _13 = _11 as *mut () (PtrToPtr);
+ _12 = move _13 as usize (Transmute);
+ StorageDead(_13);
+ StorageDead(_11);
+ switchInt(move _12) -> [0: bb6, otherwise: bb7];
+ }
+
+ bb5: {
+ _9 = const {0x1 as *mut [bool; 0]} as *const [bool; 0] (PointerCoercion(MutToConstPointer));
+ _5 = NonNull::<[bool; 0]> { pointer: _9 };
  StorageDead(_9);
  StorageDead(_8);
  StorageDead(_6);
@@ -87,20 +121,22 @@
  _3 = move _4 as std::ptr::Unique<[bool]> (PointerCoercion(Unsize));
  StorageDead(_4);
  _2 = Box::<[bool]>(_3, const std::alloc::Global);
+ StorageDead(_10);
  StorageDead(_3);
  _1 = A { foo: move _2 };
  StorageDead(_2);
  _0 = const ();
  drop(_1) -> [return: bb1, unwind: bb2];
  }
 
- bb1: {
- StorageDead(_1);
- return;
+ bb6: {
+ StorageDead(_12);
+ _10 = core::panicking::panic_nounwind(const "unsafe precondition(s) violated: NonNull::new_unchecked requires that the pointer is non-null") -> unwind unreachable;
  }
 
- bb2 (cleanup): {
- resume;
+ bb7: {
+ StorageDead(_12);
+ goto -> bb5;
  }
  }