Rollup merge of rust-lang#48353 - michaelwoerister:monoitem-static-defid, r=eddyb

Allow for instantiating statics from upstream crates

This PR makes the infrastructure around translating statics a bit more flexible so that it can also instantiate statics from upstream crates if the need arises. This is preparatory work for a MIR-only RLIBs prototype, where the instantiation of a `static` may be deferred until a leaf crate.

r? @eddyb (feel free to assign to someone else if you're busy)

Author: Manishearth

src/librustc/dep_graph/dep_node.rs

@@ -628,7 +628,7 @@ define_dep_nodes!( <'tcx>
     [eval_always] CollectAndPartitionTranslationItems,
     [] ExportName(DefId),
     [] ContainsExternIndicator(DefId),
-    [] IsTranslatedFunction(DefId),
+    [] IsTranslatedItem(DefId),
     [] CodegenUnit(InternedString),
     [] CompileCodegenUnit(InternedString),
     [input] OutputFilenames,

src/librustc/hir/map/mod.rs

@@ -22,6 +22,7 @@ use hir::def_id::{CRATE_DEF_INDEX, DefId, LocalDefId, DefIndexAddressSpace};
 use syntax::abi::Abi;
 use syntax::ast::{self, Name, NodeId, CRATE_NODE_ID};
 use syntax::codemap::Spanned;
+use syntax::ext::base::MacroKind;
 use syntax_pos::Span;
 
 use hir::*;
@@ -32,13 +33,15 @@ use util::nodemap::{DefIdMap, FxHashMap};
 use arena::TypedArena;
 use std::cell::RefCell;
 use std::io;
+use ty::TyCtxt;
 
 pub mod blocks;
 mod collector;
 mod def_collector;
 pub mod definitions;
 mod hir_id_validator;
 
+
 pub const ITEM_LIKE_SPACE: DefIndexAddressSpace = DefIndexAddressSpace::Low;
 pub const REGULAR_SPACE: DefIndexAddressSpace = DefIndexAddressSpace::High;
 
@@ -373,6 +376,92 @@ impl<'hir> Map<'hir> {
         self.definitions.as_local_node_id(def_id.to_def_id()).unwrap()
     }
 
+    pub fn describe_def(&self, node_id: NodeId) -> Option<Def> {
+        let node = if let Some(node) = self.find(node_id) {
+            node
+        } else {
+            return None
+        };
+
+        match node {
+            NodeItem(item) => {
+                let def_id = || {
+                    self.local_def_id(item.id)
+                };
+
+                match item.node {
+                    ItemStatic(_, m, _) => Some(Def::Static(def_id(),
+                                                            m == MutMutable)),
+                    ItemConst(..) => Some(Def::Const(def_id())),
+                    ItemFn(..) => Some(Def::Fn(def_id())),
+                    ItemMod(..) => Some(Def::Mod(def_id())),
+                    ItemGlobalAsm(..) => Some(Def::GlobalAsm(def_id())),
+                    ItemTy(..) => Some(Def::TyAlias(def_id())),
+                    ItemEnum(..) => Some(Def::Enum(def_id())),
+                    ItemStruct(..) => Some(Def::Struct(def_id())),
+                    ItemUnion(..) => Some(Def::Union(def_id())),
+                    ItemTrait(..) => Some(Def::Trait(def_id())),
+                    ItemTraitAlias(..) => {
+                        bug!("trait aliases are not yet implemented (see issue #41517)")
+                    },
+                    ItemExternCrate(_) |
+                    ItemUse(..) |
+                    ItemForeignMod(..) |
+                    ItemImpl(..) => None,
+                }
+            }
+            NodeForeignItem(item) => {
+                let def_id = self.local_def_id(item.id);
+                match item.node {
+                    ForeignItemFn(..) => Some(Def::Fn(def_id)),
+                    ForeignItemStatic(_, m) => Some(Def::Static(def_id, m)),
+                    ForeignItemType => Some(Def::TyForeign(def_id)),
+                }
+            }
+            NodeTraitItem(item) => {
+                let def_id = self.local_def_id(item.id);
+                match item.node {
+                    TraitItemKind::Const(..) => Some(Def::AssociatedConst(def_id)),
+                    TraitItemKind::Method(..) => Some(Def::Method(def_id)),
+                    TraitItemKind::Type(..) => Some(Def::AssociatedTy(def_id)),
+                }
+            }
+            NodeImplItem(item) => {
+                let def_id = self.local_def_id(item.id);
+                match item.node {
+                    ImplItemKind::Const(..) => Some(Def::AssociatedConst(def_id)),
+                    ImplItemKind::Method(..) => Some(Def::Method(def_id)),
+                    ImplItemKind::Type(..) => Some(Def::AssociatedTy(def_id)),
+                }
+            }
+            NodeVariant(variant) => {
+                let def_id = self.local_def_id(variant.node.data.id());
+                Some(Def::Variant(def_id))
+            }
+            NodeField(_) |
+            NodeExpr(_) |
+            NodeStmt(_) |
+            NodeTy(_) |
+            NodeTraitRef(_) |
+            NodePat(_) |
+            NodeBinding(_) |
+            NodeStructCtor(_) |
+            NodeLifetime(_) |
+            NodeVisibility(_) |
+            NodeBlock(_) => None,
+            NodeLocal(local) => {
+                Some(Def::Local(local.id))
+            }
+            NodeMacroDef(macro_def) => {
+                Some(Def::Macro(self.local_def_id(macro_def.id),
+                                MacroKind::Bang))
+            }
+            NodeTyParam(param) => {
+                Some(Def::TyParam(self.local_def_id(param.id)))
+            }
+        }
+    }
+
     fn entry_count(&self) -> usize {
         self.map.len()
     }
@@ -1275,3 +1364,12 @@ fn node_id_to_string(map: &Map, id: NodeId, include_id: bool) -> String {
         }
     }
 }
+
+pub fn describe_def(tcx: TyCtxt, def_id: DefId) -> Option<Def> {
+    if let Some(node_id) = tcx.hir.as_local_node_id(def_id) {
+        tcx.hir.describe_def(node_id)
+    } else {
+        bug!("Calling local describe_def query provider for upstream DefId: {:?}",
+             def_id)
+    }
+}

src/librustc/hir/mod.rs

@@ -43,6 +43,7 @@ use syntax::tokenstream::TokenStream;
 use syntax::util::ThinVec;
 use syntax::util::parser::ExprPrecedence;
 use ty::AdtKind;
+use ty::maps::Providers;
 
 use rustc_data_structures::indexed_vec;
 
@@ -2204,3 +2205,8 @@ pub type TraitMap = NodeMap<Vec<TraitCandidate>>;
 // Map from the NodeId of a glob import to a list of items which are actually
 // imported.
 pub type GlobMap = NodeMap<FxHashSet<Name>>;
+
+
+pub fn provide(providers: &mut Providers) {
+    providers.describe_def = map::describe_def;
+}

src/librustc/mir/mono.rs

@@ -8,6 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+use hir::def_id::DefId;
 use syntax::ast::NodeId;
 use syntax::symbol::InternedString;
 use ty::{Instance, TyCtxt};
@@ -21,7 +22,7 @@ use std::hash::Hash;
 #[derive(PartialEq, Eq, Clone, Copy, Debug, Hash)]
 pub enum MonoItem<'tcx> {
     Fn(Instance<'tcx>),
-    Static(NodeId),
+    Static(DefId),
     GlobalAsm(NodeId),
 }
 
@@ -50,7 +51,9 @@ impl<'tcx> HashStable<StableHashingContext<'tcx>> for MonoItem<'tcx> {
             MonoItem::Fn(ref instance) => {
                 instance.hash_stable(hcx, hasher);
             }
-            MonoItem::Static(node_id)    |
+            MonoItem::Static(def_id) => {
+                def_id.hash_stable(hcx, hasher);
+            }
             MonoItem::GlobalAsm(node_id) => {
                 hcx.with_node_id_hashing_mode(NodeIdHashingMode::HashDefPath, |hcx| {
                     node_id.hash_stable(hcx, hasher);

src/librustc/ty/maps/mod.rs

@@ -350,7 +350,7 @@ define_maps! { <'tcx>
     [] fn export_name: ExportName(DefId) -> Option<Symbol>,
     [] fn contains_extern_indicator: ContainsExternIndicator(DefId) -> bool,
     [] fn symbol_export_level: GetSymbolExportLevel(DefId) -> SymbolExportLevel,
-    [] fn is_translated_function: IsTranslatedFunction(DefId) -> bool,
+    [] fn is_translated_item: IsTranslatedItem(DefId) -> bool,
     [] fn codegen_unit: CodegenUnit(InternedString) -> Arc<CodegenUnit<'tcx>>,
     [] fn compile_codegen_unit: CompileCodegenUnit(InternedString) -> Stats,
     [] fn output_filenames: output_filenames_node(CrateNum)

src/librustc/ty/maps/plumbing.rs

@@ -929,7 +929,7 @@ pub fn force_from_dep_node<'a, 'gcx, 'lcx>(tcx: TyCtxt<'a, 'gcx, 'lcx>,
         DepKind::ContainsExternIndicator => {
             force!(contains_extern_indicator, def_id!());
         }
-        DepKind::IsTranslatedFunction => { force!(is_translated_function, def_id!()); }
+        DepKind::IsTranslatedItem => { force!(is_translated_item, def_id!()); }
         DepKind::OutputFilenames => { force!(output_filenames, LOCAL_CRATE); }
 
         DepKind::TargetFeaturesWhitelist => { force!(target_features_whitelist, LOCAL_CRATE); }

src/librustc_driver/driver.rs

@@ -932,6 +932,7 @@ pub fn phase_2_configure_and_expand_inner<'a, F>(sess: &'a Session,
 }
 
 pub fn default_provide(providers: &mut ty::maps::Providers) {
+    hir::provide(providers);
     borrowck::provide(providers);
     mir::provide(providers);
     reachable::provide(providers);

src/librustc_mir/monomorphize/collector.rs

@@ -368,8 +368,7 @@ fn collect_items_rec<'a, 'tcx: 'a>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
     let recursion_depth_reset;
 
     match starting_point {
-        MonoItem::Static(node_id) => {
-            let def_id = tcx.hir.local_def_id(node_id);
+        MonoItem::Static(def_id) => {
             let instance = Instance::mono(tcx, def_id);
 
             // Sanity check whether this ended up being collected accidentally
@@ -652,8 +651,7 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirNeighborCollector<'a, 'tcx> {
         let tcx = self.tcx;
         let instance = Instance::mono(tcx, static_.def_id);
         if should_monomorphize_locally(tcx, &instance) {
-            let node_id = tcx.hir.as_local_node_id(static_.def_id).unwrap();
-            self.output.push(MonoItem::Static(node_id));
+            self.output.push(MonoItem::Static(static_.def_id));
         }
 
         self.super_static(static_, context, location);
@@ -946,10 +944,10 @@ impl<'b, 'a, 'v> ItemLikeVisitor<'v> for RootCollector<'b, 'a, 'v> {
                 self.output.push(MonoItem::GlobalAsm(item.id));
             }
             hir::ItemStatic(..) => {
+                let def_id = self.tcx.hir.local_def_id(item.id);
                 debug!("RootCollector: ItemStatic({})",
-                       def_id_to_string(self.tcx,
-                                        self.tcx.hir.local_def_id(item.id)));
-                self.output.push(MonoItem::Static(item.id));
+                       def_id_to_string(self.tcx, def_id));
+                self.output.push(MonoItem::Static(def_id));
             }
             hir::ItemConst(..) => {
                 // const items only generate mono items if they are

src/librustc_mir/monomorphize/item.rs

@@ -97,8 +97,7 @@ pub trait MonoItemExt<'a, 'tcx>: fmt::Debug {
     fn symbol_name(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> ty::SymbolName {
         match *self.as_mono_item() {
             MonoItem::Fn(instance) => tcx.symbol_name(instance),
-            MonoItem::Static(node_id) => {
-                let def_id = tcx.hir.local_def_id(node_id);
+            MonoItem::Static(def_id) => {
                 tcx.symbol_name(Instance::mono(tcx, def_id))
             }
             MonoItem::GlobalAsm(node_id) => {
@@ -159,7 +158,7 @@ pub trait MonoItemExt<'a, 'tcx>: fmt::Debug {
     fn explicit_linkage(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> Option<Linkage> {
         let def_id = match *self.as_mono_item() {
             MonoItem::Fn(ref instance) => instance.def_id(),
-            MonoItem::Static(node_id) => tcx.hir.local_def_id(node_id),
+            MonoItem::Static(def_id) => def_id,
             MonoItem::GlobalAsm(..) => return None,
         };
 
@@ -209,7 +208,7 @@ pub trait MonoItemExt<'a, 'tcx>: fmt::Debug {
         debug!("is_instantiable({:?})", self);
         let (def_id, substs) = match *self.as_mono_item() {
             MonoItem::Fn(ref instance) => (instance.def_id(), instance.substs),
-            MonoItem::Static(node_id) => (tcx.hir.local_def_id(node_id), Substs::empty()),
+            MonoItem::Static(def_id) => (def_id, Substs::empty()),
             // global asm never has predicates
             MonoItem::GlobalAsm(..) => return true
         };
@@ -218,14 +217,11 @@ pub trait MonoItemExt<'a, 'tcx>: fmt::Debug {
     }
 
     fn to_string(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> String {
-        let hir_map = &tcx.hir;
-
         return match *self.as_mono_item() {
             MonoItem::Fn(instance) => {
                 to_string_internal(tcx, "fn ", instance)
             },
-            MonoItem::Static(node_id) => {
-                let def_id = hir_map.local_def_id(node_id);
+            MonoItem::Static(def_id) => {
                 let instance = Instance::new(def_id, tcx.intern_substs(&[]));
                 to_string_internal(tcx, "static ", instance)
             },
@@ -251,7 +247,9 @@ pub trait MonoItemExt<'a, 'tcx>: fmt::Debug {
             MonoItem::Fn(Instance { def, .. }) => {
                 tcx.hir.as_local_node_id(def.def_id())
             }
-            MonoItem::Static(node_id) |
+            MonoItem::Static(def_id) => {
+                tcx.hir.as_local_node_id(def_id)
+            }
             MonoItem::GlobalAsm(node_id) => {
                 Some(node_id)
             }

src/librustc_mir/monomorphize/partitioning.rs

@@ -180,7 +180,9 @@ pub trait CodegenUnitExt<'tcx> {
                         }
                     }
                 }
-                MonoItem::Static(node_id) |
+                MonoItem::Static(def_id) => {
+                    tcx.hir.as_local_node_id(def_id)
+                }
                 MonoItem::GlobalAsm(node_id) => {
                     Some(node_id)
                 }
@@ -382,7 +384,15 @@ fn place_root_translation_items<'a, 'tcx, I>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                         };
                         (Linkage::External, visibility)
                     }
-                    MonoItem::Static(node_id) |
+                    MonoItem::Static(def_id) => {
+                        let visibility = if tcx.is_exported_symbol(def_id) {
+                            can_be_internalized = false;
+                            default_visibility(def_id)
+                        } else {
+                            Visibility::Hidden
+                        };
+                        (Linkage::External, visibility)
+                    }
                     MonoItem::GlobalAsm(node_id) => {
                         let def_id = tcx.hir.local_def_id(node_id);
                         let visibility = if tcx.is_exported_symbol(def_id) {
@@ -643,7 +653,7 @@ fn characteristic_def_id_of_trans_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 
             Some(def_id)
         }
-        MonoItem::Static(node_id) |
+        MonoItem::Static(def_id) => Some(def_id),
         MonoItem::GlobalAsm(node_id) => Some(tcx.hir.local_def_id(node_id)),
     }
 }