Merge pull request rust-lang#127 from oli-obk/print_panic

ignore `print!`, turn `panic!` into a EvalError

src/error.rs

@@ -56,6 +56,7 @@ pub enum EvalError<'tcx> {
     ExpectedConcreteFunction(Function<'tcx>),
     ExpectedDropGlue(Function<'tcx>),
     ManuallyCalledDropGlue,
+    Panic,
 }
 
 pub type EvalResult<'tcx, T = ()> = Result<T, EvalError<'tcx>>;
@@ -134,6 +135,8 @@ impl<'tcx> Error for EvalError<'tcx> {
                 "tried to use non-drop-glue function as drop glue",
             EvalError::ManuallyCalledDropGlue =>
                 "tried to manually invoke drop glue",
+            EvalError::Panic =>
+                "the evaluated program panicked",
         }
     }
 

src/terminator/mod.rs

@@ -292,7 +292,25 @@ impl<'a, 'tcx> EvalContext<'a, 'tcx> {
                     }
                 }
 
-                let mir = self.load_mir(resolved_def_id)?;
+                let mir = match self.load_mir(resolved_def_id) {
+                    Ok(mir) => mir,
+                    Err(EvalError::NoMirFor(path)) => {
+                        match &path[..] {
+                            // let's just ignore all output for now
+                            "std::io::_print" => {
+                                self.goto_block(destination.unwrap().1);
+                                return Ok(());
+                            },
+                            "std::thread::Builder::new" => return Err(EvalError::Unimplemented("miri does not support threading".to_owned())),
+                            "std::env::args" => return Err(EvalError::Unimplemented("miri does not support program arguments".to_owned())),
+                            "std::panicking::rust_panic_with_hook" |
+                            "std::rt::begin_panic_fmt" => return Err(EvalError::Panic),
+                            _ => {},
+                        }
+                        return Err(EvalError::NoMirFor(path));
+                    },
+                    Err(other) => return Err(other),
+                };
                 let (return_lvalue, return_to_block) = match destination {
                     Some((lvalue, block)) => (lvalue, StackPopCleanup::Goto(block)),
                     None => {

tests/compile-fail/env_args.rs

@@ -1,6 +1,4 @@
-//error-pattern: no mir for `std::env::args`
-
 fn main() {
-    let x = std::env::args();
+    let x = std::env::args(); //~ ERROR miri does not support program arguments
     assert_eq!(x.count(), 1);
 }

tests/compile-fail/panic.rs

@@ -0,0 +1,5 @@
+//error-pattern: the evaluated program panicked
+
+fn main() {
+    assert_eq!(5, 6);
+}