Allow _Unwind_RaiseException with MinGW

Author: bjorn3

src/tools/miri/src/shims/windows/foreign_items.rs

@@ -758,6 +758,22 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
                 this.write_null(dest)?;
             }
 
+            "_Unwind_RaiseException" => {
+                // This is not formally part of POSIX, but it is very wide-spread on POSIX systems.
+                // It was originally specified as part of the Itanium C++ ABI:
+                // https://itanium-cxx-abi.github.io/cxx-abi/abi-eh.html#base-throw.
+                // MinGW implements _Unwind_RaiseException on top of SEH exceptions.
+                if this.tcx.sess.target.env != "gnu" {
+                    throw_unsup_format!(
+                        "`_Unwind_RaiseException` is not supported on non-MinGW Windows",
+                    );
+                }
+                // This function looks and behaves excatly like miri_start_unwind.
+                let [payload] = this.check_shim(abi, Abi::C { unwind: true }, link_name, args)?;
+                this.handle_miri_start_unwind(payload)?;
+                return Ok(EmulateItemResult::NeedsUnwind);
+            }
+
             _ => return Ok(EmulateItemResult::NotSupported),
         }