with this, we support panics on Windows

Author: RalfJung

src/shims/foreign_items.rs

@@ -129,7 +129,6 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
                 // This matches calls to the foreign item `panic_impl`.
                 // The implementation is provided by the function with the `#[panic_handler]` attribute.
                 "panic_impl" => {
-                    this.check_panic_supported()?;
                     let panic_impl_id = tcx.lang_items().panic_impl().unwrap();
                     let panic_impl_instance = ty::Instance::mono(tcx, panic_impl_id);
                     return Ok(Some(&*this.load_mir(panic_impl_instance.def, None)?));

src/shims/mod.rs

@@ -52,14 +52,6 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
             return this.emulate_foreign_item(instance.def_id(), args, ret, unwind);
         }
 
-        // Better error message for panics on Windows.
-        let def_id = instance.def_id();
-        if Some(def_id) == this.tcx.lang_items().begin_panic_fn() ||
-            Some(def_id) == this.tcx.lang_items().panic_impl()
-        {
-            this.check_panic_supported()?;
-        }
-
         // Otherwise, load the MIR.
         Ok(Some(&*this.load_mir(instance.def, None)?))
     }

src/shims/panic.rs

@@ -34,14 +34,6 @@ pub struct CatchUnwindData<'tcx> {
 
 impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriEvalContext<'mir, 'tcx> {}
 pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx> {
-    /// Check if panicking is supported on this target, and give a good error otherwise.
-    fn check_panic_supported(&self) -> InterpResult<'tcx> {
-        match self.eval_context_ref().tcx.sess.target.target.target_os.as_str() {
-            "linux" | "macos" => Ok(()),
-            _ => throw_unsup_format!("panicking is not supported on this target"),
-        }
-    }
-
     /// Handles the special `miri_start_panic` intrinsic, which is called
     /// by libpanic_unwind to delegate the actual unwinding process to Miri.
     fn handle_miri_start_panic(

tests/compile-fail/abort-terminator.rs

@@ -1,5 +1,4 @@
 // error-pattern: the evaluated program aborted
-// ignore-windows (panics dont work on Windows)
 #![feature(unwind_attributes)]
 
 #[unwind(aborts)]

tests/compile-fail/panic/double_panic.rs

@@ -1,5 +1,4 @@
 // error-pattern: the evaluated program aborted
-// ignore-windows (panics dont work on Windows)
 
 struct Foo;
 impl Drop for Foo {

tests/compile-fail/panic/windows1.rs

@@ -1,7 +1,7 @@
-// ignore-windows: Unwind panicking does not currently work on Windows
 // normalize-stderr-test "[^ ]*libcore/[a-z/]+.rs[0-9:]*" -> "$$LOC"
 #![feature(never_type)]
 #![allow(unconditional_panic)]
+
 use std::panic::{catch_unwind, AssertUnwindSafe};
 use std::cell::Cell;
 

tests/compile-fail/panic/windows2.rs

@@ -1,4 +1,3 @@
-// ignore-windows: Unwind panicking does not currently work on Windows
 #![allow(unconditional_panic)]
 
 fn main() {