Make MIR encodable and store it in crate metadata.

src/librustc/middle/const_eval.rs

@@ -242,7 +242,7 @@ pub fn lookup_const_fn_by_id<'tcx>(tcx: &ty::ctxt<'tcx>, def_id: DefId)
     }
 }
 
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
 pub enum ConstVal {
     Float(f64),
     Int(i64),

src/librustc/middle/cstore.rs

@@ -28,6 +28,7 @@ use middle::def;
 use middle::lang_items;
 use middle::ty::{self, Ty};
 use middle::def_id::{DefId, DefIndex};
+use mir::repr::Mir;
 use session::Session;
 use session::search_paths::PathKind;
 use util::nodemap::{FnvHashMap, NodeMap, NodeSet};
@@ -100,6 +101,7 @@ pub enum InlinedItem {
 }
 
 /// A borrowed version of `hir::InlinedItem`.
+#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
 pub enum InlinedItemRef<'a> {
     Item(&'a hir::Item),
     TraitItem(DefId, &'a hir::TraitItem),
@@ -216,6 +218,8 @@ pub trait CrateStore<'tcx> : Any {
     // misc. metadata
     fn maybe_get_item_ast(&'tcx self, tcx: &ty::ctxt<'tcx>, def: DefId)
                           -> FoundAst<'tcx>;
+    fn maybe_get_item_mir(&self, tcx: &ty::ctxt<'tcx>, def: DefId)
+                          -> Option<Mir<'tcx>>;
     // This is basically a 1-based range of ints, which is a little
     // silly - I may fix that.
     fn crates(&self) -> Vec<ast::CrateNum>;
@@ -235,6 +239,7 @@ pub trait CrateStore<'tcx> : Any {
                        item_symbols: &RefCell<NodeMap<String>>,
                        link_meta: &LinkMeta,
                        reachable: &NodeSet,
+                       mir_map: &NodeMap<Mir<'tcx>>,
                        krate: &hir::Crate) -> Vec<u8>;
     fn metadata_encoding_version(&self) -> &[u8];
 }
@@ -383,6 +388,9 @@ impl<'tcx> CrateStore<'tcx> for DummyCrateStore {
     // misc. metadata
     fn maybe_get_item_ast(&'tcx self, tcx: &ty::ctxt<'tcx>, def: DefId)
                           -> FoundAst<'tcx> { unimplemented!() }
+    fn maybe_get_item_mir(&self, tcx: &ty::ctxt<'tcx>, def: DefId)
+                          -> Option<Mir<'tcx>> { unimplemented!() }
+
     // This is basically a 1-based range of ints, which is a little
     // silly - I may fix that.
     fn crates(&self) -> Vec<ast::CrateNum> { vec![] }
@@ -404,6 +412,7 @@ impl<'tcx> CrateStore<'tcx> for DummyCrateStore {
                        item_symbols: &RefCell<NodeMap<String>>,
                        link_meta: &LinkMeta,
                        reachable: &NodeSet,
+                       mir_map: &NodeMap<Mir<'tcx>>,
                        krate: &hir::Crate) -> Vec<u8> { vec![] }
     fn metadata_encoding_version(&self) -> &[u8] { unimplemented!() }
 }

src/librustc/middle/ty/sty.rs

@@ -10,6 +10,7 @@
 
 //! This module contains TypeVariants and its major components
 
+use middle::cstore;
 use middle::def_id::DefId;
 use middle::region;
 use middle::subst::{self, Substs};
@@ -26,6 +27,8 @@ use syntax::abi;
 use syntax::ast::{self, Name};
 use syntax::parse::token::special_idents;
 
+use serialize::{Decodable, Decoder};
+
 use rustc_front::hir;
 
 use self::FnOutput::*;
@@ -233,7 +236,7 @@ pub enum TypeVariants<'tcx> {
 /// closure C wind up influencing the decisions we ought to make for
 /// closure C (which would then require fixed point iteration to
 /// handle). Plus it fixes an ICE. :P
-#[derive(Clone, PartialEq, Eq, Hash, Debug)]
+#[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
 pub struct ClosureSubsts<'tcx> {
     /// Lifetime and type parameters from the enclosing function.
     /// These are separated out because trans wants to pass them around
@@ -246,6 +249,23 @@ pub struct ClosureSubsts<'tcx> {
     pub upvar_tys: Vec<Ty<'tcx>>
 }
 
+impl<'tcx> Decodable for &'tcx ClosureSubsts<'tcx> {
+    fn decode<S: Decoder>(s: &mut S) -> Result<&'tcx ClosureSubsts<'tcx>, S::Error> {
+        let closure_substs = try! { Decodable::decode(s) };
+        let dummy_def_id: DefId = unsafe { mem::zeroed() };
+
+        cstore::tls::with_decoding_context(s, |dcx, _| {
+            // Intern the value
+            let ty = dcx.tcx().mk_closure_from_closure_substs(dummy_def_id,
+                                                              Box::new(closure_substs));
+            match ty.sty {
+                TyClosure(_, ref closure_substs) => Ok(&**closure_substs),
+                _ => unreachable!()
+            }
+        })
+    }
+}
+
 #[derive(Clone, PartialEq, Eq, Hash)]
 pub struct TraitTy<'tcx> {
     pub principal: ty::PolyTraitRef<'tcx>,
@@ -434,7 +454,7 @@ pub struct ClosureTy<'tcx> {
     pub sig: PolyFnSig<'tcx>,
 }
 
-#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
+#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
 pub enum FnOutput<'tcx> {
     FnConverging(Ty<'tcx>),
     FnDiverging
@@ -632,7 +652,7 @@ pub struct DebruijnIndex {
 ///
 /// [1] http://smallcultfollowing.com/babysteps/blog/2013/10/29/intermingled-parameter-lists/
 /// [2] http://smallcultfollowing.com/babysteps/blog/2013/11/04/intermingled-parameter-lists/
-#[derive(Clone, PartialEq, Eq, Hash, Copy)]
+#[derive(Clone, PartialEq, Eq, Hash, Copy, RustcEncodable, RustcDecodable)]
 pub enum Region {
     // Region bound in a type or fn declaration which will be
     // substituted 'early' -- that is, at the same time when type
@@ -701,7 +721,7 @@ pub struct RegionVid {
     pub index: u32
 }
 
-#[derive(Clone, Copy, PartialEq, Eq, Hash)]
+#[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
 pub struct SkolemizedRegionVid {
     pub index: u32
 }

src/librustc/mir/repr.rs

@@ -21,6 +21,7 @@ use std::fmt::{Debug, Formatter, Error};
 use std::u32;
 
 /// Lowered representation of a single function.
+#[derive(RustcEncodable, RustcDecodable)]
 pub struct Mir<'tcx> {
     /// List of basic blocks. References to basic block use a newtyped index type `BasicBlock`
     /// that indexes into this vector.
@@ -71,13 +72,13 @@ impl<'tcx> Mir<'tcx> {
 ///////////////////////////////////////////////////////////////////////////
 // Mutability and borrow kinds
 
-#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
 pub enum Mutability {
     Mut,
     Not,
 }
 
-#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
 pub enum BorrowKind {
     /// Data must be immutable and is aliasable.
     Shared,
@@ -128,6 +129,7 @@ pub enum BorrowKind {
 
 // A "variable" is a binding declared by the user as part of the fn
 // decl, a let, etc.
+#[derive(RustcEncodable, RustcDecodable)]
 pub struct VarDecl<'tcx> {
     pub mutability: Mutability,
     pub name: Name,
@@ -136,6 +138,7 @@ pub struct VarDecl<'tcx> {
 
 // A "temp" is a temporary that we place on the stack. They are
 // anonymous, always mutable, and have only a type.
+#[derive(RustcEncodable, RustcDecodable)]
 pub struct TempDecl<'tcx> {
     pub ty: Ty<'tcx>,
 }
@@ -151,6 +154,7 @@ pub struct TempDecl<'tcx> {
 //
 // there is only one argument, of type `(i32, u32)`, but two bindings
 // (`x` and `y`).
+#[derive(RustcEncodable, RustcDecodable)]
 pub struct ArgDecl<'tcx> {
     pub ty: Ty<'tcx>,
 }
@@ -162,7 +166,7 @@ pub struct ArgDecl<'tcx> {
 /// list of the `Mir`.
 ///
 /// (We use a `u32` internally just to save memory.)
-#[derive(Copy, Clone, PartialEq, Eq)]
+#[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable)]
 pub struct BasicBlock(u32);
 
 impl BasicBlock {
@@ -186,12 +190,13 @@ impl Debug for BasicBlock {
 ///////////////////////////////////////////////////////////////////////////
 // BasicBlock and Terminator
 
-#[derive(Debug)]
+#[derive(Debug, RustcEncodable, RustcDecodable)]
 pub struct BasicBlockData<'tcx> {
     pub statements: Vec<Statement<'tcx>>,
     pub terminator: Terminator<'tcx>,
 }
 
+#[derive(RustcEncodable, RustcDecodable)]
 pub enum Terminator<'tcx> {
     /// block should have one successor in the graph; we jump there
     Goto {
@@ -289,7 +294,7 @@ impl<'tcx> Terminator<'tcx> {
     }
 }
 
-#[derive(Debug)]
+#[derive(Debug, RustcEncodable, RustcDecodable)]
 pub struct CallData<'tcx> {
     /// where the return value is written to
     pub destination: Lvalue<'tcx>,
@@ -346,18 +351,19 @@ impl<'tcx> Debug for Terminator<'tcx> {
 ///////////////////////////////////////////////////////////////////////////
 // Statements
 
+#[derive(RustcEncodable, RustcDecodable)]
 pub struct Statement<'tcx> {
     pub span: Span,
     pub kind: StatementKind<'tcx>,
 }
 
-#[derive(Debug)]
+#[derive(Debug, RustcEncodable, RustcDecodable)]
 pub enum StatementKind<'tcx> {
     Assign(Lvalue<'tcx>, Rvalue<'tcx>),
     Drop(DropKind, Lvalue<'tcx>),
 }
 
-#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
 pub enum DropKind {
     Free, // free a partially constructed box, should go away eventually
     Deep
@@ -378,7 +384,7 @@ impl<'tcx> Debug for Statement<'tcx> {
 
 /// A path to a value; something that can be evaluated without
 /// changing or disturbing program state.
-#[derive(Clone, PartialEq)]
+#[derive(Clone, PartialEq, RustcEncodable, RustcDecodable)]
 pub enum Lvalue<'tcx> {
     /// local variable declared by the user
     Var(u32),
@@ -404,13 +410,13 @@ pub enum Lvalue<'tcx> {
 /// or `*B` or `B[index]`. Note that it is parameterized because it is
 /// shared between `Constant` and `Lvalue`. See the aliases
 /// `LvalueProjection` etc below.
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, PartialEq, RustcEncodable, RustcDecodable)]
 pub struct Projection<'tcx, B, V> {
     pub base: B,
     pub elem: ProjectionElem<'tcx, V>,
 }
 
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, PartialEq, RustcEncodable, RustcDecodable)]
 pub enum ProjectionElem<'tcx, V> {
     Deref,
     Field(Field),
@@ -448,7 +454,7 @@ pub type LvalueElem<'tcx> =
     ProjectionElem<'tcx,Operand<'tcx>>;
 
 /// Index into the list of fields found in a `VariantDef`
-#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
 pub struct Field(u32);
 
 impl Field {
@@ -524,7 +530,7 @@ impl<'tcx> Debug for Lvalue<'tcx> {
 // lvalue). They are intentionally limited to prevent rvalues from
 // being nested in one another.
 
-#[derive(Clone, PartialEq)]
+#[derive(Clone, PartialEq, RustcEncodable, RustcDecodable)]
 pub enum Operand<'tcx> {
     Consume(Lvalue<'tcx>),
     Constant(Constant<'tcx>),
@@ -543,7 +549,7 @@ impl<'tcx> Debug for Operand<'tcx> {
 ///////////////////////////////////////////////////////////////////////////
 // Rvalues
 
-#[derive(Clone)]
+#[derive(Clone, RustcEncodable, RustcDecodable)]
 pub enum Rvalue<'tcx> {
     // x (either a move or copy, depending on type of x)
     Use(Operand<'tcx>),
@@ -587,7 +593,7 @@ pub enum Rvalue<'tcx> {
     InlineAsm(InlineAsm),
 }
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
 pub enum CastKind {
     Misc,
 
@@ -605,7 +611,7 @@ pub enum CastKind {
     Unsize,
 }
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
 pub enum AggregateKind<'tcx> {
     Vec,
     Tuple,
@@ -613,7 +619,7 @@ pub enum AggregateKind<'tcx> {
     Closure(DefId, &'tcx ClosureSubsts<'tcx>),
 }
 
-#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
 pub enum BinOp {
     /// The `+` operator (addition)
     Add,
@@ -649,7 +655,7 @@ pub enum BinOp {
     Gt,
 }
 
-#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
 pub enum UnOp {
     /// The `!` operator for logical inversion
     Not,
@@ -685,14 +691,14 @@ impl<'tcx> Debug for Rvalue<'tcx> {
 // this does not necessarily mean that they are "==" in Rust -- in
 // particular one must be wary of `NaN`!
 
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, PartialEq, RustcEncodable, RustcDecodable)]
 pub struct Constant<'tcx> {
     pub span: Span,
     pub ty: Ty<'tcx>,
     pub literal: Literal<'tcx>,
 }
 
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, PartialEq, RustcEncodable, RustcDecodable)]
 pub enum Literal<'tcx> {
     Item {
         def_id: DefId,

src/librustc_metadata/common.rs

@@ -120,7 +120,8 @@ enum_from_u32! {
 
         tag_tree = 0x51,
 
-        // GAP 0x52
+        tag_mir = 0x52,
+
         tag_table = 0x53,
         // GAP 0x54, 0x55
         tag_table_def = 0x56,

src/librustc_metadata/csearch.rs

@@ -22,6 +22,7 @@ use middle::ty::{self, Ty};
 use middle::def_id::{DefId, DefIndex};
 
 use rustc::front::map as hir_map;
+use rustc::mir::repr::Mir;
 use rustc::util::nodemap::{FnvHashMap, NodeMap, NodeSet};
 
 use std::cell::RefCell;
@@ -421,6 +422,12 @@ impl<'tcx> CrateStore<'tcx> for cstore::CStore {
         decoder::maybe_get_item_ast(&*cdata, tcx, def.index, decode_inlined_item)
     }
 
+    fn maybe_get_item_mir(&self, tcx: &ty::ctxt<'tcx>, def: DefId)
+                          -> Option<Mir<'tcx>> {
+        let cdata = self.get_crate_data(def.krate);
+        decoder::maybe_get_item_mir(&*cdata, tcx, def.index)
+    }
+
     fn crates(&self) -> Vec<ast::CrateNum>
     {
         let mut result = vec![];
@@ -473,6 +480,7 @@ impl<'tcx> CrateStore<'tcx> for cstore::CStore {
                        item_symbols: &RefCell<NodeMap<String>>,
                        link_meta: &LinkMeta,
                        reachable: &NodeSet,
+                       mir_map: &NodeMap<Mir<'tcx>>,
                        krate: &hir::Crate) -> Vec<u8>
     {
         let encode_inlined_item: encoder::EncodeInlinedItem =
@@ -486,7 +494,8 @@ impl<'tcx> CrateStore<'tcx> for cstore::CStore {
             link_meta: link_meta,
             cstore: self,
             encode_inlined_item: encode_inlined_item,
-            reachable: reachable
+            reachable: reachable,
+            mir_map: mir_map,
         };
         encoder::encode_metadata(encode_params, krate)
 

src/librustc_metadata/decoder.rs

@@ -18,6 +18,7 @@ use cstore::{self, crate_metadata};
 use common::*;
 use encoder::def_to_u64;
 use index;
+use tls_context;
 use tydecode::TyDecoder;
 
 use rustc::back::svh::Svh;
@@ -26,7 +27,7 @@ use rustc::util::nodemap::FnvHashMap;
 use rustc_front::hir;
 
 use middle::cstore::{LOCAL_CRATE, FoundAst, InlinedItem, LinkagePreference};
-use middle::cstore::{DefLike, DlDef, DlField, DlImpl};
+use middle::cstore::{DefLike, DlDef, DlField, DlImpl, tls};
 use middle::def;
 use middle::def_id::{DefId, DefIndex};
 use middle::lang_items;
@@ -34,6 +35,9 @@ use middle::subst;
 use middle::ty::{ImplContainer, TraitContainer};
 use middle::ty::{self, RegionEscape, Ty};
 
+use rustc::mir;
+use rustc::mir::visit::MutVisitor;
+
 use std::cell::{Cell, RefCell};
 use std::io::prelude::*;
 use std::io;
@@ -48,7 +52,7 @@ use syntax::parse::token::{IdentInterner, special_idents};
 use syntax::parse::token;
 use syntax::ast;
 use syntax::abi;
-use syntax::codemap;
+use syntax::codemap::{self, Span};
 use syntax::print::pprust;
 use syntax::ptr::P;
 
@@ -783,6 +787,56 @@ pub fn maybe_get_item_ast<'tcx>(cdata: Cmd, tcx: &ty::ctxt<'tcx>, id: DefIndex,
     }
 }
 
+pub fn maybe_get_item_mir<'tcx>(cdata: Cmd,
+                                tcx: &ty::ctxt<'tcx>,
+                                id: DefIndex)
+                                -> Option<mir::repr::Mir<'tcx>> {
+    let item_doc = cdata.lookup_item(id);
+
+    return reader::maybe_get_doc(item_doc, tag_mir as usize).map(|mir_doc| {
+        let dcx = tls_context::DecodingContext {
+            crate_metadata: cdata,
+            tcx: tcx,
+        };
+        let mut decoder = reader::Decoder::new(mir_doc);
+
+        let mut mir = tls::enter_decoding_context(&dcx, &mut decoder, |_, decoder| {
+            Decodable::decode(decoder).unwrap()
+        });
+
+        let mut def_id_and_span_translator = MirDefIdAndSpanTranslator {
+            crate_metadata: cdata,
+            codemap: tcx.sess.codemap(),
+            last_filemap_index_hint: Cell::new(0),
+        };
+
+        def_id_and_span_translator.visit_mir(&mut mir);
+
+        mir
+    });
+
+    struct MirDefIdAndSpanTranslator<'cdata, 'codemap> {
+        crate_metadata: Cmd<'cdata>,
+        codemap: &'codemap codemap::CodeMap,
+        last_filemap_index_hint: Cell<usize>
+    }
+
+    impl<'v, 'cdata, 'codemap> mir::visit::MutVisitor<'v>
+        for MirDefIdAndSpanTranslator<'cdata, 'codemap>
+    {
+        fn visit_def_id(&mut self, def_id: &mut DefId) {
+            *def_id = translate_def_id(self.crate_metadata, *def_id);
+        }
+
+        fn visit_span(&mut self, span: &mut Span) {
+            *span = translate_span(self.crate_metadata,
+                                   self.codemap,
+                                   &self.last_filemap_index_hint,
+                                   *span);
+        }
+    }
+}
+
 fn get_explicit_self(item: rbml::Doc) -> ty::ExplicitSelfCategory {
     fn get_mutability(ch: u8) -> hir::Mutability {
         match ch as char {

src/librustc_metadata/encoder.rs

@@ -30,6 +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::session::config;
 use rustc::util::nodemap::{FnvHashMap, NodeMap, NodeSet};
 
@@ -64,6 +65,7 @@ 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 struct EncodeContext<'a, 'tcx: 'a> {
@@ -76,6 +78,7 @@ 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>>,
 }
 
 impl<'a, 'tcx> EncodeContext<'a,'tcx> {
@@ -840,7 +843,24 @@ fn encode_inlined_item(ecx: &EncodeContext,
                        ii: InlinedItemRef) {
     let mut eii = ecx.encode_inlined_item.borrow_mut();
     let eii: &mut EncodeInlinedItem = &mut *eii;
-    eii(ecx, rbml_w, ii)
+    eii(ecx, rbml_w, ii);
+
+    encode_mir(ecx, rbml_w, ii);
+}
+
+fn encode_mir(ecx: &EncodeContext, rbml_w: &mut Encoder, ii: InlinedItemRef) {
+    let id = match ii {
+        InlinedItemRef::Item(item) => item.id,
+        InlinedItemRef::TraitItem(_, trait_item) => trait_item.id,
+        InlinedItemRef::ImplItem(_, impl_item) => impl_item.id,
+        InlinedItemRef::Foreign(foreign_item) => foreign_item.id
+    };
+
+    if let Some(mir) = ecx.mir_map.get(&id) {
+        rbml_w.start_tag(tag_mir as usize);
+        Encodable::encode(mir, rbml_w).unwrap();
+        rbml_w.end_tag();
+    }
 }
 
 const FN_FAMILY: char = 'f';
@@ -1884,6 +1904,7 @@ pub fn encode_metadata(parms: EncodeParams, krate: &hir::Crate) -> Vec<u8> {
         encode_inlined_item,
         link_meta,
         reachable,
+        mir_map,
         ..
     } = parms;
     let ecx = EncodeContext {
@@ -1896,6 +1917,7 @@ pub fn encode_metadata(parms: EncodeParams, krate: &hir::Crate) -> Vec<u8> {
         encode_inlined_item: RefCell::new(encode_inlined_item),
         type_abbrevs: RefCell::new(FnvHashMap()),
         reachable: reachable,
+        mir_map: mir_map,
     };
 
     let mut wr = Cursor::new(Vec::new());

src/librustc_trans/trans/base.rs

@@ -2760,7 +2760,11 @@ fn register_method(ccx: &CrateContext,
     }
 }
 
-pub fn write_metadata(cx: &SharedCrateContext, krate: &hir::Crate, reachable: &NodeSet) -> Vec<u8> {
+pub fn write_metadata<'a, 'tcx>(cx: &SharedCrateContext<'a, 'tcx>,
+                                krate: &hir::Crate,
+                                reachable: &NodeSet,
+                                mir_map: &MirMap<'tcx>)
+                                -> Vec<u8> {
     use flate;
 
     let any_library = cx.sess()
@@ -2773,9 +2777,13 @@ pub fn write_metadata(cx: &SharedCrateContext, krate: &hir::Crate, reachable: &N
     }
 
     let cstore = &cx.tcx().sess.cstore;
-    let metadata = cstore.encode_metadata(
-        cx.tcx(), cx.export_map(), cx.item_symbols(), cx.link_meta(), reachable,
-        krate);
+    let metadata = cstore.encode_metadata(cx.tcx(),
+                                          cx.export_map(),
+                                          cx.item_symbols(),
+                                          cx.link_meta(),
+                                          reachable,
+                                          mir_map,
+                                          krate);
     let mut compressed = cstore.metadata_encoding_version().to_vec();
     compressed.extend_from_slice(&flate::deflate_bytes(&metadata));
 
@@ -3045,7 +3053,7 @@ pub fn trans_crate<'tcx>(tcx: &ty::ctxt<'tcx>,
     let reachable_symbol_ids = filter_reachable_ids(&shared_ccx);
 
     // Translate the metadata.
-    let metadata = write_metadata(&shared_ccx, krate, &reachable_symbol_ids);
+    let metadata = write_metadata(&shared_ccx, krate, &reachable_symbol_ids, mir_map);
 
     if shared_ccx.sess().trans_stats() {
         let stats = shared_ccx.stats();