Add helper function for unsupported functionality

Author: landaire

src/shims/foreign_items.rs

@@ -164,7 +164,10 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
                         "the program aborted execution".to_owned()
                     ))
                 }
-                _ => throw_unsup_format!("can't call (diverging) foreign function: {}", link_name),
+                _ => {
+                    this.handle_unsupported(format!("can't call (diverging) foreign function: {}", link_name))?;
+                    return Ok(None);
+                },
             },
             Some(p) => p,
         };

src/shims/panic.rs

@@ -161,7 +161,24 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         }
     }
 
-    /// Starta a panic in the interpreter with the given message as payload.
+    /// Handler that should be called when unsupported functionality is encountered.
+    /// This function will either panic within the context of the emulated application
+    /// or return an error in the Miri process context
+    /// 
+    /// Return value of `Ok(bool)` indicates whether execution should continue.
+    fn handle_unsupported<S: AsRef<str>>(&mut self, error_msg: S) -> InterpResult<'tcx, ()> {
+        let error = format!("unsupported Miri functionality: {}", error_msg.as_ref());
+
+        if self.eval_context_ref().machine.panic_on_unsupported {
+            // message is slightly different here to make automated analysis easier
+            self.start_panic(error.as_ref(), StackPopUnwind::Skip)?;
+            return Ok(());
+        } else {
+            throw_unsup_format!("{}", error);
+        }
+    }
+
+    /// Start a panic in the interpreter with the given message as payload.
     fn start_panic(&mut self, msg: &str, unwind: StackPopUnwind) -> InterpResult<'tcx> {
         let this = self.eval_context_mut();
 

src/shims/posix/linux/foreign_items.rs

@@ -183,17 +183,8 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
                         futex(this, args, dest)?;
                     }
                     id => {
-                        let error_msg = format!(
-                            "unsupported Miri functionality: syscall ID {} is not emulated",
-                            id
-                        );
-                        if this.eval_context_ref().machine.panic_on_unsupported {
-                            // message is slightly different here to make automated analysis easier
-                            this.start_panic(error_msg.as_ref(), StackPopUnwind::Skip)?;
-                            return Ok(false);
-                        } else {
-                            throw_unsup_format!("{}", error_msg);
-                        }
+                        this.handle_unsupported(format!("syscall ID {} is not emulated", id))?;
+                        return Ok(false);
                     }
                 }
             }
@@ -227,17 +218,11 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
             }
 
             _ => {
-                let error_msg = format!(
-                    "unsupported Miri functionality: can't call foreign function {:?}",
+                this.handle_unsupported(format!(
+                    "can't call foreign function {:?}",
                     link_name
-                );
-                if this.eval_context_ref().machine.panic_on_unsupported {
-                    // message is slightly different here to make automated analysis easier
-                    this.start_panic(error_msg.as_ref(), StackPopUnwind::Skip)?;
-                    return Ok(false);
-                } else {
-                    throw_unsup_format!("{}", error_msg);
-                }
+                ))?;
+                return Ok(false);
             }
         };
 

src/shims/posix/macos/foreign_items.rs

@@ -157,17 +157,12 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
             }
 
             _ => {
-                let error_msg = format!(
-                    "unsupported Miri functionality: can't call foreign function {:?}",
+                this.handle_unsupported(format!(
+                    "can't call foreign function {:?}",
                     link_name
-                );
-                if this.eval_context_ref().machine.panic_on_unsupported {
-                    // message is slightly different here to make automated analysis easier
-                    this.start_panic(error_msg.as_ref(), StackPopUnwind::Skip)?;
-                    return Ok(false);
-                } else {
-                    throw_unsup_format!("{}", error_msg);
-                }
+                ))?;
+
+                return Ok(false);
             }
         };
 

src/shims/windows/foreign_items.rs

@@ -343,14 +343,8 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
             "CreateThread" => {
                 check_abi(abi, Abi::System { unwind: false })?;
 
-                let error_msg =
-                    "unsupported Miri functionality: concurrency is not supported on Windows";
-                if this.eval_context_ref().machine.panic_on_unsupported {
-                    this.start_panic(error_msg, StackPopUnwind::Skip)?;
-                    return Ok(false);
-                } else {
-                    throw_unsup_format!("{}", error_msg);
-                }
+                this.handle_unsupported("concurrency is not supported on Windows")?;
+                return Ok(false);
             }
 
             // Incomplete shims that we "stub out" just to get pre-main initialization code to work.
@@ -424,17 +418,8 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
             }
 
             _ => {
-                let error_msg = format!(
-                    "unsupported Miri functionality: can't call foreign function {:?}",
-                    link_name
-                );
-                if this.eval_context_ref().machine.panic_on_unsupported {
-                    // message is slightly different here to make automated analysis easier
-                    this.start_panic(error_msg.as_ref(), StackPopUnwind::Skip)?;
-                    return Ok(false);
-                } else {
-                    throw_unsup_format!("{}", error_msg);
-                }
+                this.handle_unsupported(format!("can't call foreign function {:?}", link_name))?;
+                return Ok(false);
             }
         }