Auto merge of #58631 - spastorino:place2_1, r=oli-obk

Put Local, Static and Promoted as one Base variant of Place

Related to #52708

The `Place` 2.0 representation use a `Base` variant for `Local`, `Static` and `Promoted` so we start making this change in the current `Place` to make the following steps simpler.

r? @oli-obk

Author: bors

src/librustc/ich/impls_mir.rs

@@ -209,13 +209,13 @@ impl<'a, 'gcx> HashStable<StableHashingContext<'a>> for mir::Place<'gcx> {
                                           hasher: &mut StableHasher<W>) {
         mem::discriminant(self).hash_stable(hcx, hasher);
         match *self {
-            mir::Place::Local(ref local) => {
+            mir::Place::Base(mir::PlaceBase::Local(ref local)) => {
                 local.hash_stable(hcx, hasher);
             }
-            mir::Place::Static(ref statik) => {
+            mir::Place::Base(mir::PlaceBase::Static(ref statik)) => {
                 statik.hash_stable(hcx, hasher);
             }
-            mir::Place::Promoted(ref promoted) => {
+            mir::Place::Base(mir::PlaceBase::Promoted(ref promoted)) => {
                 promoted.hash_stable(hcx, hasher);
             }
             mir::Place::Projection(ref place_projection) => {

src/librustc/mir/mod.rs

@@ -1896,6 +1896,14 @@ impl<'tcx> Debug for Statement<'tcx> {
 /// changing or disturbing program state.
 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable)]
 pub enum Place<'tcx> {
+    Base(PlaceBase<'tcx>),
+
+    /// projection out of a place (access a field, deref a pointer, etc)
+    Projection(Box<PlaceProjection<'tcx>>),
+}
+
+#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable)]
+pub enum PlaceBase<'tcx> {
     /// local variable
     Local(Local),
 
@@ -1904,9 +1912,6 @@ pub enum Place<'tcx> {
 
     /// Constant code promoted to an injected static
     Promoted(Box<(Promoted, Ty<'tcx>)>),
-
-    /// projection out of a place (access a field, deref a pointer, etc)
-    Projection(Box<PlaceProjection<'tcx>>),
 }
 
 /// The `DefId` of a static, along with its normalized type (which is
@@ -1994,6 +1999,8 @@ newtype_index! {
 }
 
 impl<'tcx> Place<'tcx> {
+    pub const RETURN_PLACE: Place<'tcx> = Place::Base(PlaceBase::Local(RETURN_PLACE));
+
     pub fn field(self, f: Field, ty: Ty<'tcx>) -> Place<'tcx> {
         self.elem(ProjectionElem::Field(f, ty))
     }
@@ -2020,9 +2027,9 @@ impl<'tcx> Place<'tcx> {
     // FIXME: can we safely swap the semantics of `fn base_local` below in here instead?
     pub fn local(&self) -> Option<Local> {
         match self {
-            Place::Local(local) |
+            Place::Base(PlaceBase::Local(local)) |
             Place::Projection(box Projection {
-                base: Place::Local(local),
+                base: Place::Base(PlaceBase::Local(local)),
                 elem: ProjectionElem::Deref,
             }) => Some(*local),
             _ => None,
@@ -2032,9 +2039,9 @@ impl<'tcx> Place<'tcx> {
     /// Finds the innermost `Local` from this `Place`.
     pub fn base_local(&self) -> Option<Local> {
         match self {
-            Place::Local(local) => Some(*local),
+            Place::Base(PlaceBase::Local(local)) => Some(*local),
             Place::Projection(box Projection { base, elem: _ }) => base.base_local(),
-            Place::Promoted(..) | Place::Static(..) => None,
+            Place::Base(PlaceBase::Promoted(..)) | Place::Base(PlaceBase::Static(..)) => None,
         }
     }
 }
@@ -2044,14 +2051,19 @@ impl<'tcx> Debug for Place<'tcx> {
         use self::Place::*;
 
         match *self {
-            Local(id) => write!(fmt, "{:?}", id),
-            Static(box self::Static { def_id, ty }) => write!(
+            Base(PlaceBase::Local(id)) => write!(fmt, "{:?}", id),
+            Base(PlaceBase::Static(box self::Static { def_id, ty })) => write!(
                 fmt,
                 "({}: {:?})",
                 ty::tls::with(|tcx| tcx.item_path_str(def_id)),
                 ty
             ),
-            Promoted(ref promoted) => write!(fmt, "({:?}: {:?})", promoted.0, promoted.1),
+            Base(PlaceBase::Promoted(ref promoted)) => write!(
+                fmt,
+                "({:?}: {:?})",
+                promoted.0,
+                promoted.1
+            ),
             Projection(ref data) => match data.elem {
                 ProjectionElem::Downcast(ref adt_def, index) => {
                     write!(fmt, "({:?} as {})", data.base, adt_def.variants[index].ident)

src/librustc/mir/tcx.rs

@@ -158,10 +158,10 @@ impl<'tcx> Place<'tcx> {
         where D: HasLocalDecls<'tcx>
     {
         match *self {
-            Place::Local(index) =>
+            Place::Base(PlaceBase::Local(index)) =>
                 PlaceTy::Ty { ty: local_decls.local_decls()[index].ty },
-            Place::Promoted(ref data) => PlaceTy::Ty { ty: data.1 },
-            Place::Static(ref data) =>
+            Place::Base(PlaceBase::Promoted(ref data)) => PlaceTy::Ty { ty: data.1 },
+            Place::Base(PlaceBase::Static(ref data)) =>
                 PlaceTy::Ty { ty: data.ty },
             Place::Projection(ref proj) =>
                 proj.base.ty(local_decls, tcx).projection_ty(tcx, &proj.elem),

src/librustc/mir/visit.rs

@@ -733,13 +733,13 @@ macro_rules! make_mir_visitor {
                             context: PlaceContext<'tcx>,
                             location: Location) {
                 match place {
-                    Place::Local(local) => {
+                    Place::Base(PlaceBase::Local(local)) => {
                         self.visit_local(local, context, location);
                     }
-                    Place::Static(static_) => {
+                    Place::Base(PlaceBase::Static(static_)) => {
                         self.visit_static(static_, context, location);
                     }
-                    Place::Promoted(promoted) => {
+                    Place::Base(PlaceBase::Promoted(promoted)) => {
                         self.visit_ty(& $($mutability)? promoted.1, TyContext::Location(location));
                     },
                     Place::Projection(proj) => {

src/librustc_codegen_ssa/mir/analyze.rs

@@ -103,7 +103,7 @@ impl<'mir, 'a: 'mir, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> Visitor<'tcx>
                     location: Location) {
         debug!("visit_assign(block={:?}, place={:?}, rvalue={:?})", block, place, rvalue);
 
-        if let mir::Place::Local(index) = *place {
+        if let mir::Place::Base(mir::PlaceBase::Local(index)) = *place {
             self.assign(index, location);
             if !self.fx.rvalue_creates_operand(rvalue) {
                 self.not_ssa(index);
@@ -245,7 +245,8 @@ impl<'mir, 'a: 'mir, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> Visitor<'tcx>
             }
 
             PlaceContext::MutatingUse(MutatingUseContext::Drop) => {
-                let ty = mir::Place::Local(local).ty(self.fx.mir, self.fx.cx.tcx());
+                let ty = mir::Place::Base(mir::PlaceBase::Local(local)).ty(self.fx.mir,
+                                                                           self.fx.cx.tcx());
                 let ty = self.fx.monomorphize(&ty.to_ty(self.fx.cx.tcx()));
 
                 // Only need the place if we're actually dropping it.

src/librustc_codegen_ssa/mir/block.rs

@@ -249,7 +249,7 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
 
             PassMode::Direct(_) | PassMode::Pair(..) => {
                 let op =
-                    self.codegen_consume(&mut bx, &mir::Place::Local(mir::RETURN_PLACE));
+                    self.codegen_consume(&mut bx, &mir::Place::RETURN_PLACE);
                 if let Ref(llval, _, align) = op.val {
                     bx.load(llval, align)
                 } else {
@@ -615,8 +615,12 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                         // The shuffle array argument is usually not an explicit constant,
                         // but specified directly in the code. This means it gets promoted
                         // and we can then extract the value by evaluating the promoted.
-                        mir::Operand::Copy(mir::Place::Promoted(box(index, ty))) |
-                        mir::Operand::Move(mir::Place::Promoted(box(index, ty))) => {
+                        mir::Operand::Copy(
+                            mir::Place::Base(mir::PlaceBase::Promoted(box(index, ty)))
+                        ) |
+                        mir::Operand::Move(
+                            mir::Place::Base(mir::PlaceBase::Promoted(box(index, ty)))
+                        ) => {
                             let param_env = ty::ParamEnv::reveal_all();
                             let cid = mir::interpret::GlobalId {
                                 instance: self.instance,
@@ -1106,7 +1110,7 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         if fn_ret.is_ignore() {
             return ReturnDest::Nothing;
         }
-        let dest = if let mir::Place::Local(index) = *dest {
+        let dest = if let mir::Place::Base(mir::PlaceBase::Local(index)) = *dest {
             match self.locals[index] {
                 LocalRef::Place(dest) => dest,
                 LocalRef::UnsizedPlace(_) => bug!("return type must be sized"),
@@ -1161,7 +1165,7 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         src: &mir::Operand<'tcx>,
         dst: &mir::Place<'tcx>
     ) {
-        if let mir::Place::Local(index) = *dst {
+        if let mir::Place::Base(mir::PlaceBase::Local(index)) = *dst {
             match self.locals[index] {
                 LocalRef::Place(place) => self.codegen_transmute_into(bx, src, place),
                 LocalRef::UnsizedPlace(_) => bug!("transmute must not involve unsized locals"),

src/librustc_codegen_ssa/mir/operand.rs

@@ -378,7 +378,7 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
 
         // watch out for locals that do not have an
         // alloca; they are handled somewhat differently
-        if let mir::Place::Local(index) = *place {
+        if let mir::Place::Base(mir::PlaceBase::Local(index)) = *place {
             match self.locals[index] {
                 LocalRef::Operand(Some(o)) => {
                     return Some(o);

src/librustc_codegen_ssa/mir/place.rs

@@ -392,7 +392,7 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         let cx = self.cx;
         let tcx = self.cx.tcx();
 
-        if let mir::Place::Local(index) = *place {
+        if let mir::Place::Base(mir::PlaceBase::Local(index)) = *place {
             match self.locals[index] {
                 LocalRef::Place(place) => {
                     return place;
@@ -407,8 +407,8 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         }
 
         let result = match *place {
-            mir::Place::Local(_) => bug!(), // handled above
-            mir::Place::Promoted(box (index, ty)) => {
+            mir::Place::Base(mir::PlaceBase::Local(_)) => bug!(), // handled above
+            mir::Place::Base(mir::PlaceBase::Promoted(box (index, ty))) => {
                 let param_env = ty::ParamEnv::reveal_all();
                 let cid = mir::interpret::GlobalId {
                     instance: self.instance,
@@ -435,7 +435,7 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                     }
                 }
             }
-            mir::Place::Static(box mir::Static { def_id, ty }) => {
+            mir::Place::Base(mir::PlaceBase::Static(box mir::Static { def_id, ty })) => {
                 // NB: The layout of a static may be unsized as is the case when working
                 // with a static that is an extern_type.
                 let layout = cx.layout_of(self.monomorphize(&ty));
@@ -457,7 +457,9 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                         cg_base.project_field(bx, field.index())
                     }
                     mir::ProjectionElem::Index(index) => {
-                        let index = &mir::Operand::Copy(mir::Place::Local(index));
+                        let index = &mir::Operand::Copy(
+                            mir::Place::Base(mir::PlaceBase::Local(index))
+                        );
                         let index = self.codegen_operand(bx, index);
                         let llindex = index.immediate();
                         cg_base.project_index(bx, llindex)

src/librustc_codegen_ssa/mir/rvalue.rs

@@ -534,7 +534,7 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
     ) -> Bx::Value {
         // ZST are passed as operands and require special handling
         // because codegen_place() panics if Local is operand.
-        if let mir::Place::Local(index) = *place {
+        if let mir::Place::Base(mir::PlaceBase::Local(index)) = *place {
             if let LocalRef::Operand(Some(op)) = self.locals[index] {
                 if let ty::Array(_, n) = op.layout.ty.sty {
                     let n = n.unwrap_usize(bx.cx().tcx());

src/librustc_codegen_ssa/mir/statement.rs

@@ -17,7 +17,7 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         self.set_debug_loc(&mut bx, statement.source_info);
         match statement.kind {
             mir::StatementKind::Assign(ref place, ref rvalue) => {
-                if let mir::Place::Local(index) = *place {
+                if let mir::Place::Base(mir::PlaceBase::Local(index)) = *place {
                     match self.locals[index] {
                         LocalRef::Place(cg_dest) => {
                             self.codegen_rvalue(bx, cg_dest, rvalue)