Move error reporting to its own module

src/diagnostics.rs

@@ -0,0 +1,62 @@
+use rustc_mir::interpret::InterpErrorInfo;
+
+use crate::*;
+
+pub 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;
+
+        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);
+    }
+
+    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;
+}

src/eval.rs

@@ -8,7 +8,6 @@ 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::*;
 
@@ -209,62 +208,3 @@ pub fn eval_main<'tcx>(tcx: TyCtxt<'tcx>, main_id: DefId, config: MiriConfig) ->
         Err(e) => report_err(&ecx, e),
     }
 }
-
-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;
-
-        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);
-    }
-
-    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;
-}

src/lib.rs

@@ -16,6 +16,7 @@ extern crate rustc_data_structures;
 extern crate rustc_mir;
 extern crate rustc_target;
 
+mod diagnostics;
 mod eval;
 mod helpers;
 mod intptrcast;
@@ -41,6 +42,7 @@ pub use crate::shims::time::EvalContextExt as TimeEvalContextExt;
 pub use crate::shims::tls::{EvalContextExt as TlsEvalContextExt, TlsData};
 pub use crate::shims::EvalContextExt as ShimsEvalContextExt;
 
+pub use crate::diagnostics::report_err;
 pub use crate::eval::{create_ecx, eval_main, MiriConfig, TerminationInfo};
 pub use crate::helpers::EvalContextExt as HelpersEvalContextExt;
 pub use crate::machine::{