disable type validity assertions for better error messages

src/intrinsics/mod.rs

@@ -30,6 +30,7 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
         unwind: mir::UnwindAction,
     ) -> InterpResult<'tcx, Option<ty::Instance<'tcx>>> {
         let this = self.eval_context_mut();
+        let intrinsic_name = this.tcx.item_name(instance.def_id());
 
         // Force use of fallback body, if available.
         if this.machine.force_intrinsic_fallback
@@ -41,11 +42,23 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
             }));
         }
 
+        // Overwrite some core engine intrinsics that are used to catch UB -- we have better
+        // errors if we detect this UB ourselves.
+        match intrinsic_name {
+            sym::assert_inhabited
+            | sym::assert_zero_valid
+            | sym::assert_mem_uninitialized_valid => {
+                // Make these a NOP.
+                this.return_to_block(ret)?;
+                return interp_ok(None);
+            }
+            _ => {}
+        }
+
         // See if the core engine can handle this intrinsic.
         if this.eval_intrinsic(instance, args, dest, ret)? {
             return interp_ok(None);
         }
-        let intrinsic_name = this.tcx.item_name(instance.def_id());
         let intrinsic_name = intrinsic_name.as_str();
 
         // FIXME: avoid allocating memory

tests/fail/intrinsics/uninit_uninhabited_type.rs

@@ -1,11 +1,6 @@
-//@normalize-stderr-test: "\|.*::abort\(\).*" -> "| ABORT()"
-//@normalize-stderr-test: "\| +\^+" -> "| ^"
-//@normalize-stderr-test: "\n +[0-9]+:[^\n]+" -> ""
-//@normalize-stderr-test: "\n +at [^\n]+" -> ""
-//@error-in-other-file: aborted execution
 #![feature(never_type)]
 
 #[allow(deprecated, invalid_value)]
 fn main() {
-    let _ = unsafe { std::mem::uninitialized::<!>() };
+    let _ = unsafe { std::mem::uninitialized::<!>() }; //~ERROR: constructing invalid value
 }

tests/fail/intrinsics/uninit_uninhabited_type.stderr

@@ -1,27 +1,13 @@
-
-thread 'main' panicked at RUSTLIB/core/src/panicking.rs:LL:CC:
-aborted execution: attempted to instantiate uninhabited type `!`
-note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
-note: in Miri, you may have to set `MIRIFLAGS=-Zmiri-env-forward=RUST_BACKTRACE` for the environment variable to have an effect
-thread caused non-unwinding panic. aborting.
-error: abnormal termination: the program aborted execution
-  --> RUSTLIB/std/src/sys/pal/PLATFORM/mod.rs:LL:CC
-   |
-LL | ABORT()
-   | ^ abnormal termination occurred here
-   |
-   = note: BACKTRACE:
-   = note: inside `std::sys::pal::PLATFORM::abort_internal` at RUSTLIB/std/src/sys/pal/PLATFORM/mod.rs:LL:CC
-   = note: inside `std::panicking::rust_panic_with_hook` at RUSTLIB/std/src/panicking.rs:LL:CC
-   = note: inside closure at RUSTLIB/std/src/panicking.rs:LL:CC
-   = note: inside `std::sys::backtrace::__rust_end_short_backtrace::<{closure@std::panicking::begin_panic_handler::{closure#0}}, !>` at RUSTLIB/std/src/sys/backtrace.rs:LL:CC
-   = note: inside `std::panicking::begin_panic_handler` at RUSTLIB/std/src/panicking.rs:LL:CC
-   = note: inside `core::panicking::panic_nounwind` at RUSTLIB/core/src/panicking.rs:LL:CC
-note: inside `main`
+error: Undefined Behavior: constructing invalid value at .value: encountered a value of the never type `!`
   --> tests/fail/intrinsics/uninit_uninhabited_type.rs:LL:CC
    |
 LL |     let _ = unsafe { std::mem::uninitialized::<!>() };
-   | ^
+   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Undefined Behavior occurred here
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at tests/fail/intrinsics/uninit_uninhabited_type.rs:LL:CC
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 

tests/fail/intrinsics/zero_fn_ptr.rs

@@ -1,10 +1,4 @@
-//@normalize-stderr-test: "\|.*::abort\(\).*" -> "| ABORT()"
-//@normalize-stderr-test: "\| +\^+" -> "| ^"
-//@normalize-stderr-test: "\n +[0-9]+:[^\n]+" -> ""
-//@normalize-stderr-test: "\n +at [^\n]+" -> ""
-//@error-in-other-file: aborted execution
-
 #[allow(deprecated, invalid_value)]
 fn main() {
-    let _ = unsafe { std::mem::zeroed::<fn()>() };
+    let _ = unsafe { std::mem::zeroed::<fn()>() }; //~ERROR: constructing invalid value
 }

tests/fail/intrinsics/zero_fn_ptr.stderr

@@ -1,27 +1,13 @@
-
-thread 'main' panicked at RUSTLIB/core/src/panicking.rs:LL:CC:
-aborted execution: attempted to zero-initialize type `fn()`, which is invalid
-note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
-note: in Miri, you may have to set `MIRIFLAGS=-Zmiri-env-forward=RUST_BACKTRACE` for the environment variable to have an effect
-thread caused non-unwinding panic. aborting.
-error: abnormal termination: the program aborted execution
-  --> RUSTLIB/std/src/sys/pal/PLATFORM/mod.rs:LL:CC
-   |
-LL | ABORT()
-   | ^ abnormal termination occurred here
-   |
-   = note: BACKTRACE:
-   = note: inside `std::sys::pal::PLATFORM::abort_internal` at RUSTLIB/std/src/sys/pal/PLATFORM/mod.rs:LL:CC
-   = note: inside `std::panicking::rust_panic_with_hook` at RUSTLIB/std/src/panicking.rs:LL:CC
-   = note: inside closure at RUSTLIB/std/src/panicking.rs:LL:CC
-   = note: inside `std::sys::backtrace::__rust_end_short_backtrace::<{closure@std::panicking::begin_panic_handler::{closure#0}}, !>` at RUSTLIB/std/src/sys/backtrace.rs:LL:CC
-   = note: inside `std::panicking::begin_panic_handler` at RUSTLIB/std/src/panicking.rs:LL:CC
-   = note: inside `core::panicking::panic_nounwind` at RUSTLIB/core/src/panicking.rs:LL:CC
-note: inside `main`
+error: Undefined Behavior: constructing invalid value at .value: encountered a null function pointer
   --> tests/fail/intrinsics/zero_fn_ptr.rs:LL:CC
    |
 LL |     let _ = unsafe { std::mem::zeroed::<fn()>() };
-   | ^
+   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^ Undefined Behavior occurred here
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at tests/fail/intrinsics/zero_fn_ptr.rs:LL:CC
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace