Auto merge of #31425 - oli-obk:mir-pass-plugin, r=nagisa

depends on #31324

r? @nagisa

20 files changed, 196 insertions, 55 deletions

diff --git a/mk/crates.mk b/mk/crates.mk
index f47c4857ef8..3021727cb10 100644
--- a/mk/crates.mk
+++ b/mk/crates.mk
@@ -106,7 +106,7 @@ DEPS_rustc_passes := syntax rustc core rustc_front
 DEPS_rustc_mir := rustc rustc_front syntax
 DEPS_rustc_resolve := arena rustc rustc_front log syntax
 DEPS_rustc_platform_intrinsics := rustc rustc_llvm
-DEPS_rustc_plugin := rustc rustc_metadata syntax
+DEPS_rustc_plugin := rustc rustc_metadata syntax rustc_mir
 DEPS_rustc_privacy := rustc rustc_front log syntax
 DEPS_rustc_trans := arena flate getopts graphviz libc rustc rustc_back rustc_mir \
                     log syntax serialize rustc_llvm rustc_front rustc_platform_intrinsics
diff --git a/src/librustc/lib.rs b/src/librustc/lib.rs
index f88034d142a..53fd867e7fd 100644
--- a/src/librustc/lib.rs
+++ b/src/librustc/lib.rs
@@ -126,6 +126,8 @@ pub mod mir {
     pub mod repr;
     pub mod tcx;
     pub mod visit;
+    pub mod transform;
+    pub mod mir_map;
 }
 
 pub mod session;
diff --git a/src/librustc/middle/cstore.rs b/src/librustc/middle/cstore.rs
index 8355154ad21..1e21d6aabe9 100644
--- a/src/librustc/middle/cstore.rs
+++ b/src/librustc/middle/cstore.rs
@@ -29,6 +29,7 @@ use middle::lang_items;
 use middle::ty::{self, Ty, VariantKind};
 use middle::def_id::{DefId, DefIndex};
 use mir::repr::Mir;
+use mir::mir_map::MirMap;
 use session::Session;
 use session::search_paths::PathKind;
 use util::nodemap::{FnvHashMap, NodeMap, NodeSet};
@@ -244,7 +245,7 @@ pub trait CrateStore<'tcx> : Any {
                        item_symbols: &RefCell<NodeMap<String>>,
                        link_meta: &LinkMeta,
                        reachable: &NodeSet,
-                       mir_map: &NodeMap<Mir<'tcx>>,
+                       mir_map: &MirMap<'tcx>,
                        krate: &hir::Crate) -> Vec<u8>;
     fn metadata_encoding_version(&self) -> &[u8];
 }
@@ -428,7 +429,7 @@ impl<'tcx> CrateStore<'tcx> for DummyCrateStore {
                        item_symbols: &RefCell<NodeMap<String>>,
                        link_meta: &LinkMeta,
                        reachable: &NodeSet,
-                       mir_map: &NodeMap<Mir<'tcx>>,
+                       mir_map: &MirMap<'tcx>,
                        krate: &hir::Crate) -> Vec<u8> { vec![] }
     fn metadata_encoding_version(&self) -> &[u8] { unimplemented!() }
 }
diff --git a/src/librustc/mir/mir_map.rs b/src/librustc/mir/mir_map.rs
new file mode 100644
index 00000000000..aa24f6d8979
--- /dev/null
+++ b/src/librustc/mir/mir_map.rs
@@ -0,0 +1,28 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use util::nodemap::NodeMap;
+use mir::repr::Mir;
+use mir::transform::MirPass;
+use middle::ty;
+
+pub struct MirMap<'tcx> {
+    pub map: NodeMap<Mir<'tcx>>,
+}
+
+impl<'tcx> MirMap<'tcx> {
+    pub fn run_passes(&mut self, passes: &mut [Box<MirPass>], tcx: &ty::ctxt<'tcx>) {
+        for (_, ref mut mir) in &mut self.map {
+            for pass in &mut *passes {
+                pass.run_on_mir(mir, tcx)
+            }
+        }
+    }
+}
diff --git a/src/librustc/mir/transform.rs b/src/librustc/mir/transform.rs
new file mode 100644
index 00000000000..0f18d8d2821
--- /dev/null
+++ b/src/librustc/mir/transform.rs
@@ -0,0 +1,16 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use mir::repr::Mir;
+use middle::ty::ctxt;
+
+pub trait MirPass {
+    fn run_on_mir<'tcx>(&mut self, mir: &mut Mir<'tcx>, tcx: &ctxt<'tcx>);
+}
diff --git a/src/librustc/session/mod.rs b/src/librustc/session/mod.rs
index f0c71825942..d2f8d3f09fd 100644
--- a/src/librustc/session/mod.rs
+++ b/src/librustc/session/mod.rs
@@ -13,6 +13,7 @@ use middle::cstore::CrateStore;
 use middle::dependency_format;
 use session::search_paths::PathKind;
 use util::nodemap::{NodeMap, FnvHashMap};
+use mir::transform::MirPass;
 
 use syntax::ast::{NodeId, NodeIdAssigner, Name};
 use syntax::codemap::{Span, MultiSpan};
@@ -59,6 +60,7 @@ pub struct Session {
     pub lint_store: RefCell<lint::LintStore>,
     pub lints: RefCell<NodeMap<Vec<(lint::LintId, Span, String)>>>,
     pub plugin_llvm_passes: RefCell<Vec<String>>,
+    pub plugin_mir_passes: RefCell<Vec<Box<MirPass>>>,
     pub plugin_attributes: RefCell<Vec<(String, AttributeType)>>,
     pub crate_types: RefCell<Vec<config::CrateType>>,
     pub dependency_formats: RefCell<dependency_format::Dependencies>,
@@ -475,6 +477,7 @@ pub fn build_session_(sopts: config::Options,
         lint_store: RefCell::new(lint::LintStore::new()),
         lints: RefCell::new(NodeMap()),
         plugin_llvm_passes: RefCell::new(Vec::new()),
+        plugin_mir_passes: RefCell::new(Vec::new()),
         plugin_attributes: RefCell::new(Vec::new()),
         crate_types: RefCell::new(Vec::new()),
         dependency_formats: RefCell::new(FnvHashMap()),
diff --git a/src/librustc_driver/driver.rs b/src/librustc_driver/driver.rs
index e5066399323..6c5b577e0d1 100644
--- a/src/librustc_driver/driver.rs
+++ b/src/librustc_driver/driver.rs
@@ -12,7 +12,7 @@ use rustc::dep_graph::DepGraph;
 use rustc::front;
 use rustc::front::map as hir_map;
 use rustc_mir as mir;
-use rustc_mir::mir_map::MirMap;
+use rustc::mir::mir_map::MirMap;
 use rustc::session::{Session, CompileResult, compile_result_from_err_count};
 use rustc::session::config::{self, Input, OutputFilenames, OutputType};
 use rustc::session::search_paths::PathKind;
@@ -545,7 +545,7 @@ pub fn phase_2_configure_and_expand(sess: &Session,
     });
 
     let Registry { syntax_exts, early_lint_passes, late_lint_passes, lint_groups,
-                   llvm_passes, attributes, .. } = registry;
+                   llvm_passes, attributes, mir_passes, .. } = registry;
 
     try!(sess.track_errors(|| {
         let mut ls = sess.lint_store.borrow_mut();
@@ -561,6 +561,7 @@ pub fn phase_2_configure_and_expand(sess: &Session,
         }
 
         *sess.plugin_llvm_passes.borrow_mut() = llvm_passes;
+        *sess.plugin_mir_passes.borrow_mut() = mir_passes;
         *sess.plugin_attributes.borrow_mut() = attributes.clone();
     }));
 
@@ -843,12 +844,16 @@ pub fn phase_3_run_analysis_passes<'tcx, F, R>(sess: &'tcx Session,
              "match checking",
              || middle::check_match::check_crate(tcx));
 
-        let mir_map =
+        let mut mir_map =
             time(time_passes,
                  "MIR dump",
                  || mir::mir_map::build_mir_for_crate(tcx));
 
         time(time_passes,
+             "MIR passes",
+             || mir_map.run_passes(&mut sess.plugin_mir_passes.borrow_mut(), tcx));
+
+        time(time_passes,
              "liveness checking",
              || middle::liveness::check_crate(tcx));
 
diff --git a/src/librustc_metadata/csearch.rs b/src/librustc_metadata/csearch.rs
index bc52921e1b8..06a2727ea28 100644
--- a/src/librustc_metadata/csearch.rs
+++ b/src/librustc_metadata/csearch.rs
@@ -23,6 +23,7 @@ use middle::def_id::{DefId, DefIndex};
 
 use rustc::front::map as hir_map;
 use rustc::mir::repr::Mir;
+use rustc::mir::mir_map::MirMap;
 use rustc::util::nodemap::{FnvHashMap, NodeMap, NodeSet};
 
 use std::cell::RefCell;
@@ -502,7 +503,7 @@ impl<'tcx> CrateStore<'tcx> for cstore::CStore {
                        item_symbols: &RefCell<NodeMap<String>>,
                        link_meta: &LinkMeta,
                        reachable: &NodeSet,
-                       mir_map: &NodeMap<Mir<'tcx>>,
+                       mir_map: &MirMap<'tcx>,
                        krate: &hir::Crate) -> Vec<u8>
     {
         let encode_inlined_item: encoder::EncodeInlinedItem =
diff --git a/src/librustc_metadata/encoder.rs b/src/librustc_metadata/encoder.rs
index 8df72016078..50030ced0ab 100644
--- a/src/librustc_metadata/encoder.rs
+++ b/src/librustc_metadata/encoder.rs
@@ -30,7 +30,7 @@ use middle::ty::{self, Ty};
 use rustc::back::svh::Svh;
 use rustc::front::map::{LinkedPath, PathElem, PathElems};
 use rustc::front::map as ast_map;
-use rustc::mir::repr::Mir;
+use rustc::mir::mir_map::MirMap;
 use rustc::session::config;
 use rustc::util::nodemap::{FnvHashMap, NodeMap, NodeSet};
 
@@ -66,7 +66,7 @@ pub struct EncodeParams<'a, 'tcx: 'a> {
     pub cstore: &'a cstore::CStore,
     pub encode_inlined_item: EncodeInlinedItem<'a>,
     pub reachable: &'a NodeSet,
-    pub mir_map: &'a NodeMap<Mir<'tcx>>,
+    pub mir_map: &'a MirMap<'tcx>,
 }
 
 pub struct EncodeContext<'a, 'tcx: 'a> {
@@ -79,7 +79,7 @@ pub struct EncodeContext<'a, 'tcx: 'a> {
     pub encode_inlined_item: RefCell<EncodeInlinedItem<'a>>,
     pub type_abbrevs: tyencode::abbrev_map<'tcx>,
     pub reachable: &'a NodeSet,
-    pub mir_map: &'a NodeMap<Mir<'tcx>>,
+    pub mir_map: &'a MirMap<'tcx>,
 }
 
 impl<'a, 'tcx> EncodeContext<'a,'tcx> {
@@ -824,7 +824,7 @@ fn encode_inlined_item(ecx: &EncodeContext,
 }
 
 fn encode_mir(ecx: &EncodeContext, rbml_w: &mut Encoder, node_id: NodeId) {
-    if let Some(mir) = ecx.mir_map.get(&node_id) {
+    if let Some(mir) = ecx.mir_map.map.get(&node_id) {
         rbml_w.start_tag(tag_mir as usize);
         rbml_w.emit_opaque(|opaque_encoder| {
             tls::enter_encoding_context(ecx, opaque_encoder, |_, opaque_encoder| {
@@ -1447,7 +1447,7 @@ fn my_visit_expr(expr: &hir::Expr,
 
             ecx.tcx.map.with_path(expr.id, |path| encode_path(rbml_w, path));
 
-            assert!(ecx.mir_map.contains_key(&expr.id));
+            assert!(ecx.mir_map.map.contains_key(&expr.id));
             encode_mir(ecx, rbml_w, expr.id);
 
             rbml_w.end_tag();
diff --git a/src/librustc_mir/mir_map.rs b/src/librustc_mir/mir_map.rs
index 7d4b0288a03..0e641bf679d 100644
--- a/src/librustc_mir/mir_map.rs
+++ b/src/librustc_mir/mir_map.rs
@@ -17,33 +17,34 @@
 //! - `#[rustc_mir(pretty="file.mir")]`
 
 extern crate syntax;
-extern crate rustc;
 extern crate rustc_front;
 
 use build;
 use graphviz;
 use pretty;
-use transform::{simplify_cfg, MirPass};
+use transform::simplify_cfg;
 use rustc::dep_graph::DepNode;
 use rustc::mir::repr::Mir;
 use hair::cx::Cx;
 use std::fs::File;
 
-use self::rustc::middle::infer;
-use self::rustc::middle::region::CodeExtentData;
-use self::rustc::middle::ty::{self, Ty};
-use self::rustc::util::common::ErrorReported;
-use self::rustc::util::nodemap::NodeMap;
-use self::rustc_front::hir;
-use self::rustc_front::intravisit::{self, Visitor};
-use self::syntax::ast;
-use self::syntax::attr::AttrMetaMethods;
-use self::syntax::codemap::Span;
-
-pub type MirMap<'tcx> = NodeMap<Mir<'tcx>>;
+use rustc::mir::transform::MirPass;
+use rustc::mir::mir_map::MirMap;
+use rustc::middle::infer;
+use rustc::middle::region::CodeExtentData;
+use rustc::middle::ty::{self, Ty};
+use rustc::util::common::ErrorReported;
+use rustc::util::nodemap::NodeMap;
+use rustc_front::hir;
+use rustc_front::intravisit::{self, Visitor};
+use syntax::ast;
+use syntax::attr::AttrMetaMethods;
+use syntax::codemap::Span;
 
 pub fn build_mir_for_crate<'tcx>(tcx: &ty::ctxt<'tcx>) -> MirMap<'tcx> {
-    let mut map = NodeMap();
+    let mut map = MirMap {
+        map: NodeMap(),
+    };
     {
         let mut dump = OuterDump {
             tcx: tcx,
@@ -147,7 +148,7 @@ impl<'a, 'm, 'tcx> Visitor<'tcx> for InnerDump<'a,'m,'tcx> {
 
         match build_mir(Cx::new(&infcx), implicit_arg_tys, id, span, decl, body) {
             Ok(mut mir) => {
-                simplify_cfg::SimplifyCfg::new().run_on_mir(&mut mir);
+                simplify_cfg::SimplifyCfg::new().run_on_mir(&mut mir, self.tcx);
 
                 let meta_item_list = self.attr
                                          .iter()
@@ -182,7 +183,7 @@ impl<'a, 'm, 'tcx> Visitor<'tcx> for InnerDump<'a,'m,'tcx> {
                     }
                 }
 
-                let previous = self.map.insert(id, mir);
+                let previous = self.map.map.insert(id, mir);
                 assert!(previous.is_none());
             }
             Err(ErrorReported) => {}
diff --git a/src/librustc_mir/transform/erase_regions.rs b/src/librustc_mir/transform/erase_regions.rs
index d851daffe89..b927ab489f1 100644
--- a/src/librustc_mir/transform/erase_regions.rs
+++ b/src/librustc_mir/transform/erase_regions.rs
@@ -15,24 +15,26 @@
 use rustc::middle::ty;
 use rustc::mir::repr::*;
 use rustc::mir::visit::MutVisitor;
-use mir_map::MirMap;
-use transform::MirPass;
+use rustc::mir::mir_map::MirMap;
+use rustc::mir::transform::MirPass;
 
 pub fn erase_regions<'tcx>(tcx: &ty::ctxt<'tcx>, mir_map: &mut MirMap<'tcx>) {
-    let mut eraser = EraseRegions::new(tcx);
+    let mut eraser = EraseRegions;
 
-    for mir in mir_map.iter_mut().map(|(_, v)| v) {
-        eraser.run_on_mir(mir);
+    for (_, mir) in &mut mir_map.map {
+        eraser.run_on_mir(mir, tcx);
     }
 }
 
-pub struct EraseRegions<'a, 'tcx: 'a> {
+pub struct EraseRegions;
+
+struct EraseRegionsVisitor<'a, 'tcx: 'a> {
     tcx: &'a ty::ctxt<'tcx>,
 }
 
-impl<'a, 'tcx> EraseRegions<'a, 'tcx> {
-    pub fn new(tcx: &'a ty::ctxt<'tcx>) -> EraseRegions<'a, 'tcx> {
-        EraseRegions {
+impl<'a, 'tcx> EraseRegionsVisitor<'a, 'tcx> {
+    pub fn new(tcx: &'a ty::ctxt<'tcx>) -> Self {
+        EraseRegionsVisitor {
             tcx: tcx
         }
     }
@@ -56,13 +58,13 @@ impl<'a, 'tcx> EraseRegions<'a, 'tcx> {
     }
 }
 
-impl<'a, 'tcx> MirPass<'tcx> for EraseRegions<'a, 'tcx> {
-    fn run_on_mir(&mut self, mir: &mut Mir<'tcx>) {
-        self.visit_mir(mir);
+impl MirPass for EraseRegions {
+    fn run_on_mir<'tcx>(&mut self, mir: &mut Mir<'tcx>, tcx: &ty::ctxt<'tcx>) {
+        EraseRegionsVisitor::new(tcx).visit_mir(mir);
     }
 }
 
-impl<'a, 'tcx> MutVisitor<'tcx> for EraseRegions<'a, 'tcx> {
+impl<'a, 'tcx> MutVisitor<'tcx> for EraseRegionsVisitor<'a, 'tcx> {
     fn visit_mir(&mut self, mir: &mut Mir<'tcx>) {
         self.erase_regions_return_ty(&mut mir.return_ty);
         self.erase_regions_tys(mir.var_decls.iter_mut().map(|d| &mut d.ty));
diff --git a/src/librustc_mir/transform/mod.rs b/src/librustc_mir/transform/mod.rs
index 174718f7b16..41ea4469734 100644
--- a/src/librustc_mir/transform/mod.rs
+++ b/src/librustc_mir/transform/mod.rs
@@ -11,9 +11,3 @@
 pub mod simplify_cfg;
 pub mod erase_regions;
 mod util;
-
-use rustc::mir::repr::Mir;
-
-pub trait MirPass<'tcx> {
-    fn run_on_mir(&mut self, mir: &mut Mir<'tcx>);
-}
diff --git a/src/librustc_mir/transform/simplify_cfg.rs b/src/librustc_mir/transform/simplify_cfg.rs
index 9d4c73b90f8..17c5b5f7c3c 100644
--- a/src/librustc_mir/transform/simplify_cfg.rs
+++ b/src/librustc_mir/transform/simplify_cfg.rs
@@ -11,7 +11,7 @@
 use rustc::middle::const_eval::ConstVal;
 use rustc::mir::repr::*;
 use transform::util;
-use transform::MirPass;
+use rustc::mir::transform::MirPass;
 
 pub struct SimplifyCfg;
 
@@ -118,8 +118,8 @@ impl SimplifyCfg {
     }
 }
 
-impl<'tcx> MirPass<'tcx> for SimplifyCfg {
-    fn run_on_mir(&mut self, mir: &mut Mir<'tcx>) {
+impl MirPass for SimplifyCfg {
+    fn run_on_mir<'tcx>(&mut self, mir: &mut Mir<'tcx>, _: &::rustc::middle::ty::ctxt<'tcx>) {
         let mut changed = true;
         while changed {
             changed = self.simplify_branches(mir);
diff --git a/src/librustc_plugin/lib.rs b/src/librustc_plugin/lib.rs
index c55e97412bb..464899d5d4f 100644
--- a/src/librustc_plugin/lib.rs
+++ b/src/librustc_plugin/lib.rs
@@ -71,6 +71,7 @@
 extern crate rustc;
 extern crate rustc_front;
 extern crate rustc_metadata;
+extern crate rustc_mir;
 
 pub use self::registry::Registry;
 
diff --git a/src/librustc_plugin/registry.rs b/src/librustc_plugin/registry.rs
index 3138d7fa1db..a51fd58db88 100644
--- a/src/librustc_plugin/registry.rs
+++ b/src/librustc_plugin/registry.rs
@@ -13,6 +13,8 @@
 use rustc::lint::{EarlyLintPassObject, LateLintPassObject, LintId, Lint};
 use rustc::session::Session;
 
+use rustc::mir::transform::MirPass;
+
 use syntax::ext::base::{SyntaxExtension, NamedSyntaxExtension, NormalTT};
 use syntax::ext::base::{IdentTT, MultiModifier, MultiDecorator};
 use syntax::ext::base::{MacroExpanderFn, MacroRulesTT};
@@ -54,6 +56,9 @@ pub struct Registry<'a> {
     pub late_lint_passes: Vec<LateLintPassObject>,
 
     #[doc(hidden)]
+    pub mir_passes: Vec<Box<MirPass>>,
+
+    #[doc(hidden)]
     pub lint_groups: HashMap<&'static str, Vec<LintId>>,
 
     #[doc(hidden)]
@@ -76,6 +81,7 @@ impl<'a> Registry<'a> {
             lint_groups: HashMap::new(),
             llvm_passes: vec!(),
             attributes: vec!(),
+            mir_passes: Vec::new(),
         }
     }
 
@@ -134,6 +140,11 @@ impl<'a> Registry<'a> {
         self.lint_groups.insert(name, to.into_iter().map(|x| LintId::of(x)).collect());
     }
 
+    /// Register a MIR pass
+    pub fn register_mir_pass(&mut self, pass: Box<MirPass>) {
+        self.mir_passes.push(pass);
+    }
+
     /// Register an LLVM pass.
     ///
     /// Registration with LLVM itself is handled through static C++ objects with
diff --git a/src/librustc_trans/trans/base.rs b/src/librustc_trans/trans/base.rs
index 57e69a0efa9..720ec3f1689 100644
--- a/src/librustc_trans/trans/base.rs
+++ b/src/librustc_trans/trans/base.rs
@@ -48,7 +48,7 @@ use middle::ty::adjustment::CustomCoerceUnsized;
 use rustc::dep_graph::DepNode;
 use rustc::front::map as hir_map;
 use rustc::util::common::time;
-use rustc_mir::mir_map::MirMap;
+use rustc::mir::mir_map::MirMap;
 use session::config::{self, NoDebugInfo, FullDebugInfo};
 use session::Session;
 use trans::_match;
@@ -1596,7 +1596,7 @@ pub fn new_fn_ctxt<'a, 'tcx>(ccx: &'a CrateContext<'a, 'tcx>,
         false
     };
 
-    let mir = ccx.mir_map().get(&id);
+    let mir = ccx.mir_map().map.get(&id);
 
     let mut fcx = FunctionContext {
         mir: mir,
diff --git a/src/librustc_trans/trans/collector.rs b/src/librustc_trans/trans/collector.rs
index 6ec73788598..df86685e236 100644
--- a/src/librustc_trans/trans/collector.rs
+++ b/src/librustc_trans/trans/collector.rs
@@ -400,7 +400,7 @@ fn load_mir<'a, 'tcx: 'a>(ccx: &CrateContext<'a, 'tcx>,
 
     if def_id.is_local() {
         let node_id = ccx.tcx().map.as_local_node_id(def_id).unwrap();
-        let mir_opt = ccx.mir_map().get(&node_id);
+        let mir_opt = ccx.mir_map().map.get(&node_id);
         let mir = errors::expect(ccx.sess().diagnostic(),
                              mir_opt,
                              mir_not_found_error_message);
diff --git a/src/librustc_trans/trans/context.rs b/src/librustc_trans/trans/context.rs
index 38459c1ec3c..b2ebaac665b 100644
--- a/src/librustc_trans/trans/context.rs
+++ b/src/librustc_trans/trans/context.rs
@@ -15,7 +15,7 @@ use middle::cstore::LinkMeta;
 use middle::def::ExportMap;
 use middle::def_id::DefId;
 use middle::traits;
-use rustc_mir::mir_map::MirMap;
+use rustc::mir::mir_map::MirMap;
 use trans::adt;
 use trans::base;
 use trans::builder::Builder;
diff --git a/src/test/auxiliary/dummy_mir_pass.rs b/src/test/auxiliary/dummy_mir_pass.rs
new file mode 100644
index 00000000000..df9ea4ab012
--- /dev/null
+++ b/src/test/auxiliary/dummy_mir_pass.rs
@@ -0,0 +1,52 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// force-host
+
+#![feature(plugin_registrar, rustc_private)]
+#![feature(box_syntax)]
+
+#[macro_use] extern crate rustc;
+extern crate rustc_front;
+extern crate rustc_plugin;
+extern crate syntax;
+
+use rustc::mir::transform::MirPass;
+use rustc::mir::repr::{Mir, Literal};
+use rustc::mir::visit::MutVisitor;
+use rustc::middle::ty;
+use rustc::middle::const_eval::ConstVal;
+use rustc::lint::{LateContext, LintContext, LintPass, LateLintPass, LateLintPassObject, LintArray};
+use rustc_plugin::Registry;
+use rustc_front::hir;
+use syntax::attr;
+
+struct Pass;
+
+impl MirPass for Pass {
+    fn run_on_mir<'tcx>(&mut self, mir: &mut Mir<'tcx>, tcx: &ty::ctxt<'tcx>) {
+        Visitor.visit_mir(mir)
+    }
+}
+
+struct Visitor;
+
+impl<'tcx> MutVisitor<'tcx> for Visitor {
+    fn visit_literal(&mut self, literal: &mut Literal<'tcx>) {
+        if let Literal::Value { value: ConstVal::Int(ref mut i @ 11) } = *literal {
+            *i = 42;
+        }
+    }
+}
+
+#[plugin_registrar]
+pub fn plugin_registrar(reg: &mut Registry) {
+    reg.register_mir_pass(box Pass);
+}
diff --git a/src/test/run-pass-fulldeps/mir-pass.rs b/src/test/run-pass-fulldeps/mir-pass.rs
new file mode 100644
index 00000000000..acf11e24103
--- /dev/null
+++ b/src/test/run-pass-fulldeps/mir-pass.rs
@@ -0,0 +1,24 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// aux-build:dummy_mir_pass.rs
+// ignore-stage1
+
+#![feature(plugin, rustc_attrs)]
+#![plugin(dummy_mir_pass)]
+
+#[rustc_mir]
+fn math() -> i32 {
+    11
+}
+
+pub fn main() {
+    assert_eq!(math(), 42);
+}