Split error reporting from main eval function

Author: oli-obk

src/eval.rs

@@ -8,6 +8,7 @@ use rand::SeedableRng;
 use rustc_hir::def_id::DefId;
 use rustc::ty::layout::{LayoutOf, Size};
 use rustc::ty::{self, TyCtxt};
+use rustc_mir::interpret::InterpErrorInfo;
 
 use crate::*;
 
@@ -205,64 +206,65 @@ pub fn eval_main<'tcx>(tcx: TyCtxt<'tcx>, main_id: DefId, config: MiriConfig) ->
             }
             return Some(return_code);
         }
-        Err(mut e) => {
-            // Special treatment for some error kinds
-            let msg = match e.kind {
-                InterpError::MachineStop(ref info) => {
-                    let info = info
-                        .downcast_ref::<TerminationInfo>()
-                        .expect("invalid MachineStop payload");
-                    match info {
-                        TerminationInfo::Exit(code) => return Some(*code),
-                        TerminationInfo::PoppedTrackedPointerTag(item) =>
-                            format!("popped tracked tag for item {:?}", item),
-                        TerminationInfo::Abort =>
-                            format!("the evaluated program aborted execution"),
-                    }
-                }
-                err_unsup!(NoMirFor(..)) => format!(
-                    "{}. Did you set `MIRI_SYSROOT` to a Miri-enabled sysroot? You can prepare one with `cargo miri setup`.",
-                    e
-                ),
-                InterpError::InvalidProgram(_) =>
-                    bug!("This error should be impossible in Miri: {}", e),
-                _ => e.to_string(),
-            };
-            e.print_backtrace();
-            if let Some(frame) = ecx.stack().last() {
-                let span = frame.current_source_info().unwrap().span;
+        Err(e) => report_err(&ecx, e),
+    }
+}
 
-                let msg = format!("Miri evaluation error: {}", msg);
-                let mut err = ecx.tcx.sess.struct_span_err(span, msg.as_str());
-                let frames = ecx.generate_stacktrace(None);
-                err.span_label(span, msg);
-                // We iterate with indices because we need to look at the next frame (the caller).
-                for idx in 0..frames.len() {
-                    let frame_info = &frames[idx];
-                    let call_site_is_local = frames
-                        .get(idx + 1)
-                        .map_or(false, |caller_info| caller_info.instance.def_id().is_local());
-                    if call_site_is_local {
-                        err.span_note(frame_info.call_site, &frame_info.to_string());
-                    } else {
-                        err.note(&frame_info.to_string());
-                    }
-                }
-                err.emit();
-            } else {
-                ecx.tcx.sess.err(&msg);
+fn report_err<'tcx, 'mir>(
+    ecx: &InterpCx<'mir, 'tcx, Evaluator<'tcx>>,
+    mut e: InterpErrorInfo<'tcx>,
+) -> Option<i64> {
+    // Special treatment for some error kinds
+    let msg = match e.kind {
+        InterpError::MachineStop(ref info) => {
+            let info = info.downcast_ref::<TerminationInfo>().expect("invalid MachineStop payload");
+            match info {
+                TerminationInfo::Exit(code) => return Some(*code),
+                TerminationInfo::PoppedTrackedPointerTag(item) =>
+                    format!("popped tracked tag for item {:?}", item),
+                TerminationInfo::Abort => format!("the evaluated program aborted execution"),
             }
+        }
+        err_unsup!(NoMirFor(..)) => format!(
+            "{}. Did you set `MIRI_SYSROOT` to a Miri-enabled sysroot? You can prepare one with `cargo miri setup`.",
+            e
+        ),
+        InterpError::InvalidProgram(_) => bug!("This error should be impossible in Miri: {}", e),
+        _ => e.to_string(),
+    };
+    e.print_backtrace();
+    if let Some(frame) = ecx.stack().last() {
+        let span = frame.current_source_info().unwrap().span;
 
-            for (i, frame) in ecx.stack().iter().enumerate() {
-                trace!("-------------------");
-                trace!("Frame {}", i);
-                trace!("    return: {:?}", frame.return_place.map(|p| *p));
-                for (i, local) in frame.locals.iter().enumerate() {
-                    trace!("    local {}: {:?}", i, local.value);
-                }
+        let msg = format!("Miri evaluation error: {}", msg);
+        let mut err = ecx.tcx.sess.struct_span_err(span, msg.as_str());
+        let frames = ecx.generate_stacktrace(None);
+        err.span_label(span, msg);
+        // We iterate with indices because we need to look at the next frame (the caller).
+        for idx in 0..frames.len() {
+            let frame_info = &frames[idx];
+            let call_site_is_local = frames
+                .get(idx + 1)
+                .map_or(false, |caller_info| caller_info.instance.def_id().is_local());
+            if call_site_is_local {
+                err.span_note(frame_info.call_site, &frame_info.to_string());
+            } else {
+                err.note(&frame_info.to_string());
             }
-            // Let the reported error determine the return code.
-            return None;
+        }
+        err.emit();
+    } else {
+        ecx.tcx.sess.err(&msg);
+    }
+
+    for (i, frame) in ecx.stack().iter().enumerate() {
+        trace!("-------------------");
+        trace!("Frame {}", i);
+        trace!("    return: {:?}", frame.return_place.map(|p| *p));
+        for (i, local) in frame.locals.iter().enumerate() {
+            trace!("    local {}: {:?}", i, local.value);
         }
     }
+    // Let the reported error determine the return code.
+    return None;
 }