rustc: move the MIR map into TyCtxt.

Author: eddyb

src/librustc/middle/cstore.rs

@@ -30,7 +30,6 @@ use hir::svh::Svh;
 use middle::lang_items;
 use ty::{self, Ty, TyCtxt};
 use mir::Mir;
-use mir::mir_map::MirMap;
 use session::Session;
 use session::search_paths::PathKind;
 use util::nodemap::{NodeSet, DefIdMap};
@@ -209,8 +208,7 @@ pub trait CrateStore<'tcx> {
     fn local_node_for_inlined_defid(&'tcx self, def_id: DefId) -> Option<ast::NodeId>;
     fn defid_for_inlined_node(&'tcx self, node_id: ast::NodeId) -> Option<DefId>;
 
-    fn maybe_get_item_mir<'a>(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>, def: DefId)
-                              -> Option<Mir<'tcx>>;
+    fn get_item_mir<'a>(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>, def: DefId) -> Mir<'tcx>;
     fn is_item_mir_available(&self, def: DefId) -> bool;
 
     // This is basically a 1-based range of ints, which is a little
@@ -228,8 +226,7 @@ pub trait CrateStore<'tcx> {
     fn encode_metadata<'a>(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>,
                            reexports: &def::ExportMap,
                            link_meta: &LinkMeta,
-                           reachable: &NodeSet,
-                           mir_map: &MirMap<'tcx>) -> Vec<u8>;
+                           reachable: &NodeSet) -> Vec<u8>;
     fn metadata_encoding_version(&self) -> &[u8];
 }
 
@@ -390,8 +387,8 @@ impl<'tcx> CrateStore<'tcx> for DummyCrateStore {
         bug!("defid_for_inlined_node")
     }
 
-    fn maybe_get_item_mir<'a>(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>, def: DefId)
-                              -> Option<Mir<'tcx>> { bug!("maybe_get_item_mir") }
+    fn get_item_mir<'a>(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>, def: DefId)
+                        -> Mir<'tcx> { bug!("get_item_mir") }
     fn is_item_mir_available(&self, def: DefId) -> bool {
         bug!("is_item_mir_available")
     }
@@ -412,8 +409,7 @@ impl<'tcx> CrateStore<'tcx> for DummyCrateStore {
     fn encode_metadata<'a>(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>,
                            reexports: &def::ExportMap,
                            link_meta: &LinkMeta,
-                           reachable: &NodeSet,
-                           mir_map: &MirMap<'tcx>) -> Vec<u8> { vec![] }
+                           reachable: &NodeSet) -> Vec<u8> { vec![] }
     fn metadata_encoding_version(&self) -> &[u8] { bug!("metadata_encoding_version") }
 }
 

src/librustc/mir/mir_map.rs

@@ -37,7 +37,6 @@ pub mod tcx;
 pub mod visit;
 pub mod transform;
 pub mod traversal;
-pub mod mir_map;
 
 macro_rules! newtype_index {
     ($name:ident, $debug_name:expr) => (

src/librustc/mir/mod.rs

@@ -11,7 +11,6 @@
 use dep_graph::DepNode;
 use hir;
 use hir::map::DefPathData;
-use mir::mir_map::MirMap;
 use mir::{Mir, Promoted};
 use ty::TyCtxt;
 use syntax::ast::NodeId;
@@ -85,12 +84,11 @@ pub trait Pass {
     fn disambiguator<'a>(&'a self) -> Option<Box<fmt::Display+'a>> { None }
 }
 
-/// A pass which inspects the whole MirMap.
+/// A pass which inspects the whole Mir map.
 pub trait MirMapPass<'tcx>: Pass {
     fn run_pass<'a>(
         &mut self,
         tcx: TyCtxt<'a, 'tcx, 'tcx>,
-        map: &mut MirMap<'tcx>,
         hooks: &mut [Box<for<'s> MirPassHook<'s>>]);
 }
 
@@ -114,13 +112,18 @@ pub trait MirPass<'tcx>: Pass {
 impl<'tcx, T: MirPass<'tcx>> MirMapPass<'tcx> for T {
     fn run_pass<'a>(&mut self,
                     tcx: TyCtxt<'a, 'tcx, 'tcx>,
-                    map: &mut MirMap<'tcx>,
                     hooks: &mut [Box<for<'s> MirPassHook<'s>>])
     {
-        let def_ids = map.map.keys();
+        let def_ids = tcx.mir_map.borrow().keys();
         for def_id in def_ids {
+            if !def_id.is_local() {
+                continue;
+            }
+
             let _task = tcx.dep_graph.in_task(DepNode::Mir(def_id));
-            let mir = map.map.get_mut(&def_id).unwrap();
+            let mir = &mut tcx.mir_map.borrow()[&def_id].borrow_mut();
+            tcx.dep_graph.write(DepNode::Mir(def_id));
+
             let id = tcx.map.as_local_node_id(def_id).unwrap();
             let src = MirSource::from_node(tcx, id);
 
@@ -163,11 +166,11 @@ impl<'a, 'tcx> Passes {
         passes
     }
 
-    pub fn run_passes(&mut self, tcx: TyCtxt<'a, 'tcx, 'tcx>, map: &mut MirMap<'tcx>) {
+    pub fn run_passes(&mut self, tcx: TyCtxt<'a, 'tcx, 'tcx>) {
         let Passes { ref mut passes, ref mut plugin_passes, ref mut pass_hooks } = *self;
         for pass in plugin_passes.iter_mut().chain(passes.iter_mut()) {
             time(tcx.sess.time_passes(), &*pass.name(),
-                 || pass.run_pass(tcx, map, pass_hooks));
+                 || pass.run_pass(tcx, pass_hooks));
         }
     }
 

src/librustc/mir/transform.rs

@@ -22,6 +22,7 @@ use middle::free_region::FreeRegionMap;
 use middle::region::RegionMaps;
 use middle::resolve_lifetime;
 use middle::stability;
+use mir::Mir;
 use ty::subst::{Kind, Substs};
 use traits;
 use ty::{self, TraitRef, Ty, TypeAndMut};
@@ -65,8 +66,9 @@ pub struct CtxtArenas<'tcx> {
 
     // references
     generics: TypedArena<ty::Generics<'tcx>>,
-    trait_defs: TypedArena<ty::TraitDef<'tcx>>,
-    adt_defs: TypedArena<ty::AdtDefData<'tcx, 'tcx>>,
+    trait_def: TypedArena<ty::TraitDef<'tcx>>,
+    adt_def: TypedArena<ty::AdtDefData<'tcx, 'tcx>>,
+    mir: TypedArena<RefCell<Mir<'tcx>>>,
 }
 
 impl<'tcx> CtxtArenas<'tcx> {
@@ -81,8 +83,9 @@ impl<'tcx> CtxtArenas<'tcx> {
             layout: TypedArena::new(),
 
             generics: TypedArena::new(),
-            trait_defs: TypedArena::new(),
-            adt_defs: TypedArena::new()
+            trait_def: TypedArena::new(),
+            adt_def: TypedArena::new(),
+            mir: TypedArena::new()
         }
     }
 }
@@ -358,6 +361,15 @@ pub struct GlobalCtxt<'tcx> {
 
     pub map: ast_map::Map<'tcx>,
 
+    /// Maps from the def-id of a function/method or const/static
+    /// to its MIR. Mutation is done at an item granularity to
+    /// allow MIR optimization passes to function and still
+    /// access cross-crate MIR (e.g. inlining or const eval).
+    ///
+    /// Note that cross-crate MIR appears to be always borrowed
+    /// (in the `RefCell` sense) to prevent accidental mutation.
+    pub mir_map: RefCell<DepTrackingMap<maps::Mir<'tcx>>>,
+
     // Records the free variables refrenced by every closure
     // expression. Do not track deps for this, just recompute it from
     // scratch every time.
@@ -604,6 +616,10 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         self.global_interners.arenas.generics.alloc(generics)
     }
 
+    pub fn alloc_mir(self, mir: Mir<'gcx>) -> &'gcx RefCell<Mir<'gcx>> {
+        self.global_interners.arenas.mir.alloc(RefCell::new(mir))
+    }
+
     pub fn intern_trait_def(self, def: ty::TraitDef<'gcx>)
                             -> &'gcx ty::TraitDef<'gcx> {
         let did = def.trait_ref.def_id;
@@ -617,7 +633,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
 
     pub fn alloc_trait_def(self, def: ty::TraitDef<'gcx>)
                            -> &'gcx ty::TraitDef<'gcx> {
-        self.global_interners.arenas.trait_defs.alloc(def)
+        self.global_interners.arenas.trait_def.alloc(def)
     }
 
     pub fn insert_adt_def(self, did: DefId, adt_def: ty::AdtDefMaster<'gcx>) {
@@ -633,7 +649,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
                           variants: Vec<ty::VariantDefData<'gcx, 'gcx>>)
                           -> ty::AdtDefMaster<'gcx> {
         let def = ty::AdtDefData::new(self, did, kind, variants);
-        let interned = self.global_interners.arenas.adt_defs.alloc(def);
+        let interned = self.global_interners.arenas.adt_def.alloc(def);
         self.insert_adt_def(did, interned);
         interned
     }
@@ -738,6 +754,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
             super_predicates: RefCell::new(DepTrackingMap::new(dep_graph.clone())),
             fulfilled_predicates: RefCell::new(fulfilled_predicates),
             map: map,
+            mir_map: RefCell::new(DepTrackingMap::new(dep_graph.clone())),
             freevars: RefCell::new(freevars),
             maybe_unused_trait_imports: maybe_unused_trait_imports,
             tcache: RefCell::new(DepTrackingMap::new(dep_graph.clone())),

src/librustc/ty/context.rs

@@ -10,7 +10,10 @@
 
 use dep_graph::{DepNode, DepTrackingMapConfig};
 use hir::def_id::DefId;
+use mir;
 use ty::{self, Ty};
+
+use std::cell::RefCell;
 use std::marker::PhantomData;
 use std::rc::Rc;
 use syntax::{attr, ast};
@@ -43,3 +46,4 @@ dep_map_ty! { InherentImpls: InherentImpls(DefId) -> Vec<DefId> }
 dep_map_ty! { TraitItems: TraitItems(DefId) -> Rc<Vec<ty::ImplOrTraitItem<'tcx>>> }
 dep_map_ty! { ReprHints: ReprHints(DefId) -> Rc<Vec<attr::ReprAttr>> }
 dep_map_ty! { InlinedClosures: Hir(DefId) -> ast::NodeId }
+dep_map_ty! { Mir: Mir(DefId) -> &'tcx RefCell<mir::Mir<'tcx>> }

src/librustc/ty/maps.rs

@@ -24,6 +24,7 @@ use hir::def::{Def, CtorKind, PathResolution, ExportMap};
 use hir::def_id::{CrateNum, DefId, CRATE_DEF_INDEX, LOCAL_CRATE};
 use middle::lang_items::{FnTraitLangItem, FnMutTraitLangItem, FnOnceTraitLangItem};
 use middle::region::{CodeExtent, ROOT_CODE_EXTENT};
+use mir::Mir;
 use traits;
 use ty;
 use ty::subst::{Subst, Substs};
@@ -34,7 +35,7 @@ use util::nodemap::FnvHashMap;
 
 use serialize::{self, Encodable, Encoder};
 use std::borrow::Cow;
-use std::cell::{Cell, RefCell};
+use std::cell::{Cell, RefCell, Ref};
 use std::hash::{Hash, Hasher};
 use std::iter;
 use std::ops::Deref;
@@ -2519,6 +2520,19 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
             || self.sess.cstore.item_super_predicates(self.global_tcx(), did))
     }
 
+    /// Given the did of an item, returns its MIR, borrowed immutably.
+    pub fn item_mir(self, did: DefId) -> Ref<'gcx, Mir<'gcx>> {
+        lookup_locally_or_in_crate_store("mir_map", did, &self.mir_map, || {
+            let mir = self.sess.cstore.get_item_mir(self.global_tcx(), did);
+            let mir = self.alloc_mir(mir);
+
+            // Perma-borrow MIR from extern crates to prevent mutation.
+            mem::forget(mir.borrow());
+
+            mir
+        }).borrow()
+    }
+
     /// If `type_needs_drop` returns true, then `ty` is definitely
     /// non-copy and *might* have a destructor attached; if it returns
     /// false, then `ty` definitely has no destructor (i.e. no drop glue).

src/librustc/ty/mod.rs

@@ -55,15 +55,13 @@ pub struct MoveDataParamEnv<'tcx> {
     param_env: ty::ParameterEnvironment<'tcx>,
 }
 
-pub fn borrowck_mir<'a, 'tcx: 'a>(
-    bcx: &mut BorrowckCtxt<'a, 'tcx>,
-    fk: FnKind,
-    _decl: &hir::FnDecl,
-    mir: &'a Mir<'tcx>,
-    body: &hir::Block,
-    _sp: Span,
-    id: ast::NodeId,
-    attributes: &[ast::Attribute]) {
+pub fn borrowck_mir(bcx: &mut BorrowckCtxt,
+                    fk: FnKind,
+                    _decl: &hir::FnDecl,
+                    body: &hir::Block,
+                    _sp: Span,
+                    id: ast::NodeId,
+                    attributes: &[ast::Attribute]) {
     match fk {
         FnKind::ItemFn(name, ..) |
         FnKind::Method(name, ..) => {
@@ -75,8 +73,10 @@ pub fn borrowck_mir<'a, 'tcx: 'a>(
     }
 
     let tcx = bcx.tcx;
-
     let param_env = ty::ParameterEnvironment::for_item(tcx, id);
+
+    let mir = &tcx.item_mir(tcx.map.local_def_id(id));
+
     let move_data = MoveData::gather_moves(mir, tcx, &param_env);
     let mdpe = MoveDataParamEnv { move_data: move_data, param_env: param_env };
     let flow_inits =
@@ -170,8 +170,8 @@ pub struct MirBorrowckCtxt<'b, 'a: 'b, 'tcx: 'a> {
     mir: &'b Mir<'tcx>,
     node_id: ast::NodeId,
     move_data: MoveData<'tcx>,
-    flow_inits: DataflowResults<MaybeInitializedLvals<'a, 'tcx>>,
-    flow_uninits: DataflowResults<MaybeUninitializedLvals<'a, 'tcx>>
+    flow_inits: DataflowResults<MaybeInitializedLvals<'b, 'tcx>>,
+    flow_uninits: DataflowResults<MaybeUninitializedLvals<'b, 'tcx>>
 }
 
 impl<'b, 'a: 'b, 'tcx: 'a> MirBorrowckCtxt<'b, 'a, 'tcx> {