globally cache statics and promoteds

Author: oli-obk

src/interpreter/mod.rs

@@ -37,8 +37,8 @@ struct GlobalEvalContext<'a, 'tcx: 'a> {
     /// The virtual memory system.
     memory: Memory,
 
-    /// Precomputed statics and constants
-    statics: DefIdMap<Pointer>,
+    /// Precomputed statics, constants and promoteds
+    statics: HashMap<ConstantId<'tcx>, Pointer>,
 }
 
 struct FnEvalContext<'a, 'b: 'a + 'mir, 'mir, 'tcx: 'b> {
@@ -92,9 +92,6 @@ struct Frame<'a, 'tcx: 'a> {
     /// The offset of the first temporary in `self.locals`.
     temp_offset: usize,
 
-    /// List of precomputed promoted constants
-    promoted: HashMap<usize, Pointer>,
-
     /// The index of the currently evaluated statment
     stmt: usize,
 
@@ -136,10 +133,28 @@ enum TerminatorTarget {
 
 #[derive(Clone, Debug, Eq, PartialEq, Hash)]
 enum ConstantId<'tcx> {
-    Promoted { index: usize },
+    Promoted { def_id: DefId, substs: &'tcx Substs<'tcx>, index: usize },
     Static { def_id: DefId, substs: &'tcx Substs<'tcx> },
 }
 
+impl<'tcx> ConstantId<'tcx> {
+    fn substs(&self) -> &'tcx Substs<'tcx> {
+        use self::ConstantId::*;
+        match *self {
+            Promoted { substs, .. } |
+            Static { substs, .. } => substs
+        }
+    }
+
+    fn def_id(&self) -> DefId {
+        use self::ConstantId::*;
+        match *self {
+            Promoted { def_id, .. } |
+            Static { def_id, .. } => def_id,
+        }
+    }
+}
+
 
 impl<'a, 'tcx> GlobalEvalContext<'a, 'tcx> {
     fn new(tcx: TyCtxt<'a, 'tcx, 'tcx>, mir_map: &'a MirMap<'tcx>) -> Self {
@@ -152,7 +167,7 @@ impl<'a, 'tcx> GlobalEvalContext<'a, 'tcx> {
                                    .uint_type
                                    .bit_width()
                                    .expect("Session::target::uint_type was usize")/8),
-            statics: DefIdMap(),
+            statics: HashMap::new(),
         }
     }
 
@@ -248,7 +263,6 @@ impl<'a, 'b, 'mir, 'tcx> FnEvalContext<'a, 'b, 'mir, 'tcx> {
             locals: Vec::new(),
             var_offset: num_args,
             temp_offset: num_args + num_vars,
-            promoted: HashMap::new(),
             span: span,
             def_id: def_id,
             substs: substs,
@@ -1025,10 +1039,18 @@ impl<'a, 'b, 'mir, 'tcx> FnEvalContext<'a, 'b, 'mir, 'tcx> {
                         if item_ty.ty.is_fn() {
                             Err(EvalError::Unimplemented("unimplemented: mentions of function items".to_string()))
                         } else {
-                            Ok(*self.statics.get(&def_id).expect("static should have been cached (rvalue)"))
+                            let cid = ConstantId::Static{ def_id: def_id, substs: substs };
+                            Ok(*self.statics.get(&cid).expect("static should have been cached (rvalue)"))
                         }
                     },
-                    Promoted { index } => Ok(*self.frame().promoted.get(&index).expect("a promoted constant hasn't been precomputed")),
+                    Promoted { index } => {
+                        let cid = ConstantId::Promoted {
+                            def_id: self.frame().def_id,
+                            substs: self.substs(),
+                            index: index,
+                        };
+                        Ok(*self.statics.get(&cid).expect("a promoted constant hasn't been precomputed"))
+                    },
                 }
             }
         }
@@ -1043,7 +1065,11 @@ impl<'a, 'b, 'mir, 'tcx> FnEvalContext<'a, 'b, 'mir, 'tcx> {
             Var(i) => self.frame().locals[self.frame().var_offset + i as usize],
             Temp(i) => self.frame().locals[self.frame().temp_offset + i as usize],
 
-            Static(def_id) => *self.gecx.statics.get(&def_id).expect("static should have been cached (lvalue)"),
+            Static(def_id) => {
+                let substs = self.tcx.mk_substs(subst::Substs::empty());
+                let cid = ConstantId::Static{ def_id: def_id, substs: substs };
+                *self.gecx.statics.get(&cid).expect("static should have been cached (lvalue)")
+            },
 
             Projection(ref proj) => {
                 let base = self.eval_lvalue(&proj.base)?;

src/interpreter/stepper.rs

@@ -10,7 +10,6 @@ use rustc::ty::subst::{self, Subst};
 use rustc::hir::def_id::DefId;
 use rustc::mir::visit::{Visitor, LvalueContext};
 use syntax::codemap::Span;
-use memory::Pointer;
 use std::rc::Rc;
 
 pub enum Event {
@@ -73,23 +72,11 @@ impl<'fncx, 'a, 'b: 'a + 'mir, 'mir, 'tcx: 'b> Stepper<'fncx, 'a, 'b, 'mir, 'tcx
     }
 
     fn constant(&mut self) -> EvalResult<()> {
-        match self.fncx.frame_mut().constants.pop() {
-            Some((ConstantId::Promoted { index }, span, return_ptr, mir)) => {
-                trace!("adding promoted constant {}, {:?}", index, span);
-                let substs = self.fncx.substs();
-                // FIXME: somehow encode that this is a promoted constant's frame
-                let def_id = self.fncx.frame().def_id;
-                self.fncx.push_stack_frame(def_id, span, mir, substs, Some(return_ptr));
-                self.mir = self.fncx.mir();
-            },
-            Some((ConstantId::Static { def_id, substs }, span, return_ptr, mir)) => {
-                trace!("adding static {:?}, {:?}", def_id, span);
-                self.fncx.gecx.statics.insert(def_id, return_ptr);
-                self.fncx.push_stack_frame(def_id, span, mir, substs, Some(return_ptr));
-                self.mir = self.fncx.mir();
-            },
-            None => unreachable!(),
-        }
+        let (cid, span, return_ptr, mir) = self.fncx.frame_mut().constants.pop().expect("state machine broken");
+        let def_id = cid.def_id();
+        let substs = cid.substs();
+        self.fncx.push_stack_frame(def_id, span, mir, substs, Some(return_ptr));
+        self.mir = self.fncx.mir();
         Ok(())
     }
 
@@ -164,16 +151,17 @@ struct ConstantExtractor<'a: 'c, 'b: 'a + 'mir + 'c, 'c, 'mir: 'c, 'tcx: 'a + 'b
 }
 
 impl<'a, 'b, 'c, 'mir, 'tcx> ConstantExtractor<'a, 'b, 'c, 'mir, 'tcx> {
-    fn constant(&mut self, def_id: DefId, substs: &'tcx subst::Substs<'tcx>, span: Span) {
-        if self.fncx.gecx.statics.contains_key(&def_id) {
-            return;
-        }
+    fn static_item(&mut self, def_id: DefId, substs: &'tcx subst::Substs<'tcx>, span: Span) {
         let cid = ConstantId::Static {
             def_id: def_id,
             substs: substs,
         };
+        if self.fncx.gecx.statics.contains_key(&cid) {
+            return;
+        }
         let mir = self.fncx.load_mir(def_id);
         let ptr = self.fncx.alloc_ret_ptr(mir.return_ty).expect("there's no such thing as an unreachable static");
+        self.fncx.statics.insert(cid.clone(), ptr);
         self.fncx.frame_mut().constants.push((cid, span, ptr, mir));
     }
 }
@@ -189,19 +177,24 @@ impl<'a, 'b, 'c, 'mir, 'tcx> Visitor<'tcx> for ConstantExtractor<'a, 'b, 'c, 'mi
                 if item_ty.ty.is_fn() {
                     // unimplemented
                 } else {
-                    self.constant(def_id, substs, constant.span);
+                    self.static_item(def_id, substs, constant.span);
                 }
             },
             mir::Literal::Promoted { index } => {
-                if self.fncx.frame().promoted.contains_key(&index) {
+                let cid = ConstantId::Promoted {
+                    def_id: self.fncx.frame().def_id,
+                    substs: self.fncx.substs(),
+                    index: index,
+                };
+                if self.fncx.statics.contains_key(&cid) {
                     return;
                 }
                 let mir = self.mir.promoted[index].clone();
                 let return_ty = mir.return_ty;
                 let return_ptr = self.fncx.alloc_ret_ptr(return_ty).expect("there's no such thing as an unreachable static");
-                self.fncx.frame_mut().promoted.insert(index, return_ptr);
                 let mir = CachedMir::Owned(Rc::new(mir));
-                self.fncx.frame_mut().constants.push((ConstantId::Promoted { index: index }, constant.span, return_ptr, mir));
+                self.fncx.statics.insert(cid.clone(), return_ptr);
+                self.fncx.frame_mut().constants.push((cid, constant.span, return_ptr, mir));
             }
         }
     }
@@ -211,7 +204,7 @@ impl<'a, 'b, 'c, 'mir, 'tcx> Visitor<'tcx> for ConstantExtractor<'a, 'b, 'c, 'mi
         if let mir::Lvalue::Static(def_id) = *lvalue {
             let substs = self.fncx.tcx.mk_substs(subst::Substs::empty());
             let span = self.span;
-            self.constant(def_id, substs, span);
+            self.static_item(def_id, substs, span);
         }
     }
 }