Auto merge of #50332 - Zoxc:interner-split, r=<try>

[WIP] Only lookup types in one interner

Author: bors

src/librustc/ty/context.rs

@@ -2266,15 +2266,71 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         self.mk_fn_ptr(converted_sig)
     }
 
-    // Interns a type/name combination, stores the resulting box in cx.interners,
-    // and returns the box as cast to an unsafe ptr (see comments for Ty above).
-    pub fn mk_ty(self, st: TypeVariants<'tcx>) -> Ty<'tcx> {
-        let global_interners = if !self.is_global() {
-            Some(&self.global_interners)
+    pub fn mk_ty(&self, st: TypeVariants<'tcx>) -> Ty<'tcx> {
+        let keep_in_local_tcx = super::flags::sty_in_local_arena(&st);
+
+        // HACK(eddyb) Depend on flags being accurate to
+        // determine that all contents are in the global tcx.
+        // See comments on Lift for why we can't use that.
+        if keep_in_local_tcx {
+            let mut interner = self.interners.type_.borrow_mut();
+            if let Some(&Interned(ty)) = interner.get(&st) {
+                return ty;
+            }
+
+            let flags = super::flags::FlagComputation::for_sty(&st);
+
+            assert_eq!(
+                flags.flags.intersects(ty::TypeFlags::KEEP_IN_LOCAL_TCX),
+                true);
+
+            let ty_struct = TyS {
+                sty: st,
+                flags: flags.flags,
+                region_depth: flags.depth,
+            };
+
+            // Make sure we don't end up with inference
+            // types/regions in the global tcx.
+            if self.is_global() {
+                bug!("Attempted to intern `{:?}` which contains \
+                    inference types/regions in the global type context",
+                    &ty_struct);
+            }
+
+            // Don't be &mut TyS.
+            let ty: Ty<'tcx> = self.interners.arena.alloc(ty_struct);
+            interner.insert(Interned(ty));
+            ty
         } else {
-            None
-        };
-        self.interners.intern_ty(st, global_interners)
+            let mut interner = self.global_interners.type_.borrow_mut();
+            if let Some(&Interned(ty)) = interner.get(&st) {
+                return ty;
+            }
+
+            let flags = super::flags::FlagComputation::for_sty(&st);
+
+            assert_eq!(
+                flags.flags.intersects(ty::TypeFlags::KEEP_IN_LOCAL_TCX),
+                false);
+
+            let ty_struct = TyS {
+                sty: st,
+                flags: flags.flags,
+                region_depth: flags.depth,
+            };
+
+            // This is safe because all the types the ty_struct can point to
+            // already is in the global arena
+            let ty_struct: TyS<'gcx> = unsafe {
+                mem::transmute(ty_struct)
+            };
+
+            // Don't be &mut TyS.
+            let ty: Ty<'gcx> = self.global_interners.arena.alloc(ty_struct);
+            interner.insert(Interned(ty));
+            ty
+        }
     }
 
     pub fn mk_mach_int(self, tm: ast::IntTy) -> Ty<'tcx> {

src/librustc/ty/flags.rs

@@ -250,3 +250,145 @@ impl FlagComputation {
         }
     }
 }
+
+pub(crate) fn sty_in_local_arena(st: &ty::TypeVariants) -> bool {
+    match *st {
+        ty::TyBool |
+        ty::TyChar |
+        ty::TyInt(_) |
+        ty::TyFloat(_) |
+        ty::TyUint(_) |
+        ty::TyNever |
+        ty::TyStr |
+        ty::TyForeign(..) |
+        ty::TyError |
+        ty::TyParam(..) => false,
+
+        ty::TyGenerator(_, ref substs, ref interior) => {
+            substs_in_local_arena(&substs.substs) ||
+            ty_in_local_arena(interior.witness)
+        }
+
+        ty::TyGeneratorWitness(ref ts) => {
+            tys_in_local_arena(&ts.skip_binder()[..])
+        }
+
+        ty::TyClosure(_, ref substs) => {
+            substs_in_local_arena(&substs.substs)
+        }
+
+        ty::TyInfer(infer) => {
+            match infer {
+                ty::FreshTy(_) |
+                ty::FreshIntTy(_) |
+                ty::FreshFloatTy(_) |
+                ty::CanonicalTy(_) => false,
+                ty::TyVar(_) |
+                ty::IntVar(_) |
+                ty::FloatVar(_) => true
+            }
+        }
+
+        ty::TyAdt(_, substs) => {
+            substs_in_local_arena(substs)
+        }
+
+        ty::TyProjection(ref data) => {
+            substs_in_local_arena(data.substs)
+        }
+
+        ty::TyAnon(_, substs) => {
+            substs_in_local_arena(substs)
+        }
+
+        ty::TyDynamic(ref obj, r) => {
+            for predicate in obj.skip_binder().iter() {
+                match *predicate {
+                    ty::ExistentialPredicate::Trait(tr) => {
+                        if substs_in_local_arena(tr.substs) {
+                            return true;
+                        }
+                    }
+                    ty::ExistentialPredicate::Projection(p) => {
+                        if substs_in_local_arena(p.substs) || ty_in_local_arena(p.ty) {
+                            return true;
+                        }
+                    }
+                    ty::ExistentialPredicate::AutoTrait(_) => {}
+                }
+            }
+            r.keep_in_local_tcx()
+        }
+
+        ty::TyArray(tt, len) => {
+            ty_in_local_arena(tt) ||
+            const_in_local_arena(len)
+        }
+
+        ty::TySlice(tt) => {
+            ty_in_local_arena(tt)
+        }
+
+        ty::TyRawPtr(ref m) => {
+            ty_in_local_arena(m.ty)
+        }
+
+        ty::TyRef(r, ref m) => {
+            r.keep_in_local_tcx() ||
+            ty_in_local_arena(m.ty)
+        }
+
+        ty::TyTuple(ref ts) => {
+            tys_in_local_arena(&ts[..])
+        }
+
+        ty::TyFnDef(_, substs) => {
+            substs_in_local_arena(substs)
+        }
+
+        ty::TyFnPtr(f) => {
+            tys_in_local_arena(f.skip_binder().inputs()) ||
+            ty_in_local_arena(f.skip_binder().output())
+        }
+    }
+}
+
+#[inline(always)]
+fn ty_in_local_arena(ty: Ty) -> bool {
+    ty.flags.intersects(ty::TypeFlags::KEEP_IN_LOCAL_TCX)
+}
+
+fn tys_in_local_arena(tys: &[Ty]) -> bool {
+    for &ty in tys {
+        if ty_in_local_arena(ty) {
+            return true;
+        }
+    }
+    false
+}
+
+#[inline(always)]
+fn const_in_local_arena(constant: &ty::Const) -> bool {
+    if ty_in_local_arena(constant.ty) {
+        return true;
+    }
+    match constant.val {
+        ConstVal::Value(_) => false,
+        ConstVal::Unevaluated(_, substs) => substs_in_local_arena(substs),
+    }
+}
+
+fn substs_in_local_arena(substs: &Substs) -> bool {
+    for ty in substs.types() {
+        if ty_in_local_arena(ty) {
+            return true;
+        }
+    }
+
+    for r in substs.regions() {
+        if r.keep_in_local_tcx() {
+            return true;
+        }
+    }
+    false
+}

src/librustc/ty/sty.rs

@@ -77,10 +77,9 @@ impl BoundRegion {
     }
 }
 
-/// NB: If you change this, you'll probably want to change the corresponding
-/// AST structure in libsyntax/ast.rs as well.
-#[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
-pub enum TypeVariants<'tcx> {
+macro_rules! type_variants {
+    ([$($t:tt)*][$($p:tt)*]) => {
+        $($t)*(
     /// The primitive boolean type. Written as `bool`.
     TyBool,
 
@@ -169,9 +168,24 @@ pub enum TypeVariants<'tcx> {
 
     /// A placeholder for a type which could not be computed; this is
     /// propagated to avoid useless error messages.
-    TyError,
+    TyError,)$($p)*
+    }
 }
 
+macro_rules! declare_type_variants {
+    ($($t:tt)*) => {
+        /// NB: If you change this, you'll probably want to change the corresponding
+        /// AST structure in libsyntax/ast.rs as well.
+        #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
+        pub enum TypeVariants<'tcx> {
+            $($t)*
+        }
+    }
+}
+
+type_variants!([declare_type_variants!][;]);
+
+
 /// A closure can be modeled as a struct that looks like:
 ///
 ///     struct Closure<'l0...'li, T0...Tj, CK, CS, U0...Uk> {