Add exprs map to crate, collect item blocks there

src/librustc/hir/lowering.rs

@@ -47,9 +47,12 @@ use hir::def_id::{DefIndex, DefId};
 use hir::def::{Def, PathResolution};
 use session::Session;
 use util::nodemap::NodeMap;
+use rustc_data_structures::fnv::FnvHashMap;
 
 use std::collections::BTreeMap;
 use std::iter;
+use std::mem;
+
 use syntax::ast::*;
 use syntax::errors;
 use syntax::ptr::P;
@@ -68,6 +71,7 @@ pub struct LoweringContext<'a> {
     // the form of a DefIndex) so that if we create a new node which introduces
     // a definition, then we can properly create the def id.
     parent_def: Option<DefIndex>,
+    exprs: FnvHashMap<hir::ExprId, hir::Expr>,
     resolver: &'a mut Resolver,
 
     /// The items being lowered are collected here.
@@ -104,6 +108,7 @@ pub fn lower_crate(sess: &Session,
         crate_root: std_inject::injected_crate_name(krate),
         sess: sess,
         parent_def: None,
+        exprs: FnvHashMap(),
         resolver: resolver,
         items: BTreeMap::new(),
         impl_items: BTreeMap::new(),
@@ -120,6 +125,23 @@ enum ParamMode {
 
 impl<'a> LoweringContext<'a> {
     fn lower_crate(mut self, c: &Crate) -> hir::Crate {
+        self.lower_items(c);
+        let module = self.lower_mod(&c.module);
+        let attrs = self.lower_attrs(&c.attrs);
+        let exported_macros = c.exported_macros.iter().map(|m| self.lower_macro_def(m)).collect();
+
+        hir::Crate {
+            module: module,
+            attrs: attrs,
+            span: c.span,
+            exported_macros: exported_macros,
+            items: self.items,
+            impl_items: self.impl_items,
+            exprs: mem::replace(&mut self.exprs, FnvHashMap()),
+        }
+    }
+
+    fn lower_items(&mut self, c: &Crate) {
         struct ItemLowerer<'lcx, 'interner: 'lcx> {
             lctx: &'lcx mut LoweringContext<'interner>,
         }
@@ -139,16 +161,14 @@ impl<'a> LoweringContext<'a> {
             }
         }
 
-        visit::walk_crate(&mut ItemLowerer { lctx: &mut self }, c);
+        let mut item_lowerer = ItemLowerer { lctx: self };
+        visit::walk_crate(&mut item_lowerer, c);
+    }
 
-        hir::Crate {
-            module: self.lower_mod(&c.module),
-            attrs: self.lower_attrs(&c.attrs),
-            span: c.span,
-            exported_macros: c.exported_macros.iter().map(|m| self.lower_macro_def(m)).collect(),
-            items: self.items,
-            impl_items: self.impl_items,
-        }
+    fn record_expr(&mut self, expr: hir::Expr) -> hir::ExprId {
+        let id = hir::ExprId(expr.id);
+        self.exprs.insert(id, expr);
+        id
     }
 
     fn next_id(&self) -> NodeId {

src/librustc/hir/mod.rs

@@ -33,6 +33,7 @@ pub use self::PathParameters::*;
 use hir::def::Def;
 use hir::def_id::DefId;
 use util::nodemap::{NodeMap, FxHashSet};
+use rustc_data_structures::fnv::FnvHashMap;
 
 use syntax_pos::{mk_sp, Span, ExpnId, DUMMY_SP};
 use syntax::codemap::{self, respan, Spanned};
@@ -428,6 +429,7 @@ pub struct Crate {
     pub items: BTreeMap<NodeId, Item>,
 
     pub impl_items: BTreeMap<ImplItemId, ImplItem>,
+    pub exprs: FnvHashMap<ExprId, Expr>,
 }
 
 impl Crate {
@@ -846,6 +848,15 @@ pub enum UnsafeSource {
     UserProvided,
 }
 
+#[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
+pub struct ExprId(NodeId);
+
+impl ExprId {
+    pub fn node_id(self) -> NodeId {
+        self.0
+    }
+}
+
 /// An expression
 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash)]
 pub struct Expr {