Fix panicking ui_tests framework

Author: b-NC

src/shims/env.rs

@@ -55,7 +55,7 @@ impl<'tcx> EnvVars<'tcx> {
                 };
                 if forward {
                     let var_ptr = match target_os {
-                        "linux" | "macos" =>
+                        "linux" | "macos" | "freebsd" =>
                             alloc_env_var_as_c_str(name.as_ref(), value.as_ref(), ecx)?,
                         "windows" => alloc_env_var_as_wide_str(name.as_ref(), value.as_ref(), ecx)?,
                         unsupported =>

src/shims/unix/freebsd/dlsym.rs

@@ -32,7 +32,9 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         assert!(this.tcx.sess.target.os == "freebsd");
 
         match dlsym {
-            _ => {}
+            _ => {
+                    this.write_null(dest)?;
+            }
         }
 
         trace!("{:?}", this.dump_place(**dest));

src/shims/unix/freebsd/foreign_items.rs

@@ -17,7 +17,11 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         _ret: mir::BasicBlock,
     ) -> InterpResult<'tcx, EmulateByNameResult<'mir, 'tcx>> {
         let this = self.eval_context_mut();
-        // match
+        match link_name.as_str() {
+            _ => {
+                this.write_null(dest)?;
+            }
+        }
         Ok(EmulateByNameResult::NeedsJumping)
     }
 }