Merge pull request rust-lang#20 from oli-obk/error_reporting

various fixes and refactorings

Author: solson

src/bin/miri.rs

@@ -7,11 +7,21 @@ extern crate rustc;
 extern crate rustc_driver;
 extern crate env_logger;
 extern crate log_settings;
-extern crate log;
+extern crate syntax;
+#[macro_use] extern crate log;
 
-use miri::interpreter;
+use miri::{
+    EvalContext,
+    CachedMir,
+    step,
+    EvalError,
+    Frame,
+};
 use rustc::session::Session;
 use rustc_driver::{driver, CompilerCalls};
+use rustc::ty::{TyCtxt, subst};
+use rustc::mir::mir_map::MirMap;
+use rustc::hir::def_id::DefId;
 
 struct MiriCompilerCalls;
 
@@ -25,13 +35,84 @@ impl<'a> CompilerCalls<'a> for MiriCompilerCalls {
 
         control.after_analysis.callback = Box::new(|state| {
             state.session.abort_if_errors();
-            interpreter::interpret_start_points(state.tcx.unwrap(), state.mir_map.unwrap());
+            interpret_start_points(state.tcx.unwrap(), state.mir_map.unwrap());
         });
 
         control
     }
 }
 
+
+
+fn interpret_start_points<'a, 'tcx>(
+    tcx: TyCtxt<'a, 'tcx, 'tcx>,
+    mir_map: &MirMap<'tcx>,
+) {
+    let initial_indentation = ::log_settings::settings().indentation;
+    for (&id, mir) in &mir_map.map {
+        for attr in tcx.map.attrs(id) {
+            use syntax::attr::AttrMetaMethods;
+            if attr.check_name("miri_run") {
+                let item = tcx.map.expect_item(id);
+
+                ::log_settings::settings().indentation = initial_indentation;
+
+                debug!("Interpreting: {}", item.name);
+
+                let mut ecx = EvalContext::new(tcx, mir_map);
+                let substs = tcx.mk_substs(subst::Substs::empty());
+                let return_ptr = ecx.alloc_ret_ptr(mir.return_ty, substs);
+
+                ecx.push_stack_frame(tcx.map.local_def_id(id), mir.span, CachedMir::Ref(mir), substs, return_ptr);
+
+                loop {
+                    match (step(&mut ecx), return_ptr) {
+                        (Ok(true), _) => {},
+                        (Ok(false), Some(ptr)) => if log_enabled!(::log::LogLevel::Debug) {
+                            ecx.memory().dump(ptr.alloc_id);
+                            break;
+                        },
+                        (Ok(false), None) => {
+                            warn!("diverging function returned");
+                            break;
+                        },
+                        // FIXME: diverging functions can end up here in some future miri
+                        (Err(e), _) => {
+                            report(tcx, &ecx, e);
+                            break;
+                        },
+                    }
+                }
+            }
+        }
+    }
+}
+
+fn report(tcx: TyCtxt, ecx: &EvalContext, e: EvalError) {
+    let frame = ecx.stack().last().expect("stackframe was empty");
+    let block = frame.mir.basic_block_data(frame.next_block);
+    let span = if frame.stmt < block.statements.len() {
+        block.statements[frame.stmt].span
+    } else {
+        block.terminator().span
+    };
+    let mut err = tcx.sess.struct_span_err(span, &e.to_string());
+    for &Frame { def_id, substs, span, .. } in ecx.stack().iter().rev() {
+        // FIXME(solson): Find a way to do this without this Display impl hack.
+        use rustc::util::ppaux;
+        use std::fmt;
+        struct Instance<'tcx>(DefId, &'tcx subst::Substs<'tcx>);
+        impl<'tcx> fmt::Display for Instance<'tcx> {
+            fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+                ppaux::parameterized(f, self.1, self.0, ppaux::Ns::Value, &[],
+                    |tcx| tcx.lookup_item_type(self.0).generics)
+            }
+        }
+        err.span_note(span, &format!("inside call to {}", Instance(def_id, substs)));
+    }
+    err.emit();
+}
+
 #[miri_run]
 fn main() {
     init_logger();