Shrink `LocalDecl` by 56 bytes.

By boxing `local_info`.

10 files changed, 46 insertions, 46 deletions

diff --git a/src/librustc_middle/mir/mod.rs b/src/librustc_middle/mir/mod.rs
index 599408807e9..0c1b99d871e 100644
--- a/src/librustc_middle/mir/mod.rs
+++ b/src/librustc_middle/mir/mod.rs
@@ -696,7 +696,7 @@ pub struct LocalDecl<'tcx> {
     pub mutability: Mutability,
 
     // FIXME(matthewjasper) Don't store in this in `Body`
-    pub local_info: LocalInfo<'tcx>,
+    pub local_info: Option<Box<LocalInfo<'tcx>>>,
 
     /// `true` if this is an internal local.
     ///
@@ -818,9 +818,11 @@ pub struct LocalDecl<'tcx> {
 
 // `LocalDecl` is used a lot. Make sure it doesn't unintentionally get bigger.
 #[cfg(target_arch = "x86_64")]
-static_assert_size!(LocalDecl<'_>, 128);
+static_assert_size!(LocalDecl<'_>, 72);
 
-/// Extra information about a local that's used for diagnostics.
+/// Extra information about a some locals that's used for diagnostics. (Not
+/// used for non-StaticRef temporaries, the return place, or anonymous function
+/// parameters.)
 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
 pub enum LocalInfo<'tcx> {
     /// A user-defined local variable or function parameter
@@ -831,8 +833,6 @@ pub enum LocalInfo<'tcx> {
     User(ClearCrossCrate<BindingForm<'tcx>>),
     /// A temporary created that references the static with the given `DefId`.
     StaticRef { def_id: DefId, is_thread_local: bool },
-    /// Any other temporary, the return place, or an anonymous function parameter.
-    Other,
 }
 
 impl<'tcx> LocalDecl<'tcx> {
@@ -844,16 +844,16 @@ impl<'tcx> LocalDecl<'tcx> {
     /// - or `match ... { C(x) => ... }`
     pub fn can_be_made_mutable(&self) -> bool {
         match self.local_info {
-            LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(VarBindingForm {
+            Some(box LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(VarBindingForm {
                 binding_mode: ty::BindingMode::BindByValue(_),
                 opt_ty_info: _,
                 opt_match_place: _,
                 pat_span: _,
-            }))) => true,
+            })))) => true,
 
-            LocalInfo::User(ClearCrossCrate::Set(BindingForm::ImplicitSelf(
+            Some(box LocalInfo::User(ClearCrossCrate::Set(BindingForm::ImplicitSelf(
                 ImplicitSelfKind::Imm,
-            ))) => true,
+            )))) => true,
 
             _ => false,
         }
@@ -864,14 +864,14 @@ impl<'tcx> LocalDecl<'tcx> {
     /// mutable bindings, but the inverse does not necessarily hold).
     pub fn is_nonref_binding(&self) -> bool {
         match self.local_info {
-            LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(VarBindingForm {
+            Some(box LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(VarBindingForm {
                 binding_mode: ty::BindingMode::BindByValue(_),
                 opt_ty_info: _,
                 opt_match_place: _,
                 pat_span: _,
-            }))) => true,
+            })))) => true,
 
-            LocalInfo::User(ClearCrossCrate::Set(BindingForm::ImplicitSelf(_))) => true,
+            Some(box LocalInfo::User(ClearCrossCrate::Set(BindingForm::ImplicitSelf(_)))) => true,
 
             _ => false,
         }
@@ -882,7 +882,7 @@ impl<'tcx> LocalDecl<'tcx> {
     #[inline]
     pub fn is_user_variable(&self) -> bool {
         match self.local_info {
-            LocalInfo::User(_) => true,
+            Some(box LocalInfo::User(_)) => true,
             _ => false,
         }
     }
@@ -892,7 +892,7 @@ impl<'tcx> LocalDecl<'tcx> {
     /// match arm.
     pub fn is_ref_for_guard(&self) -> bool {
         match self.local_info {
-            LocalInfo::User(ClearCrossCrate::Set(BindingForm::RefForGuard)) => true,
+            Some(box LocalInfo::User(ClearCrossCrate::Set(BindingForm::RefForGuard))) => true,
             _ => false,
         }
     }
@@ -901,7 +901,7 @@ impl<'tcx> LocalDecl<'tcx> {
     /// access that static
     pub fn is_ref_to_static(&self) -> bool {
         match self.local_info {
-            LocalInfo::StaticRef { .. } => true,
+            Some(box LocalInfo::StaticRef { .. }) => true,
             _ => false,
         }
     }
@@ -910,7 +910,7 @@ impl<'tcx> LocalDecl<'tcx> {
     /// access that static
     pub fn is_ref_to_thread_local(&self) -> bool {
         match self.local_info {
-            LocalInfo::StaticRef { is_thread_local, .. } => is_thread_local,
+            Some(box LocalInfo::StaticRef { is_thread_local, .. }) => is_thread_local,
             _ => false,
         }
     }
@@ -933,7 +933,7 @@ impl<'tcx> LocalDecl<'tcx> {
     pub fn with_source_info(ty: Ty<'tcx>, source_info: SourceInfo) -> Self {
         LocalDecl {
             mutability: Mutability::Mut,
-            local_info: LocalInfo::Other,
+            local_info: None,
             internal: false,
             is_block_tail: None,
             ty,
diff --git a/src/librustc_mir/borrow_check/diagnostics/conflict_errors.rs b/src/librustc_mir/borrow_check/diagnostics/conflict_errors.rs
index 5bc9f6df889..9eb55bca868 100644
--- a/src/librustc_mir/borrow_check/diagnostics/conflict_errors.rs
+++ b/src/librustc_mir/borrow_check/diagnostics/conflict_errors.rs
@@ -1448,15 +1448,15 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         let (place_description, assigned_span) = match local_decl {
             Some(LocalDecl {
                 local_info:
-                    LocalInfo::User(
+                    Some(box LocalInfo::User(
                         ClearCrossCrate::Clear
                         | ClearCrossCrate::Set(BindingForm::Var(VarBindingForm {
                             opt_match_place: None,
                             ..
                         })),
-                    )
-                    | LocalInfo::StaticRef { .. }
-                    | LocalInfo::Other,
+                    ))
+                    | Some(box LocalInfo::StaticRef { .. })
+                    | None,
                 ..
             })
             | None => (self.describe_any_place(place.as_ref()), assigned_span),
diff --git a/src/librustc_mir/borrow_check/diagnostics/mod.rs b/src/librustc_mir/borrow_check/diagnostics/mod.rs
index 9e4458e7104..c218e3906ff 100644
--- a/src/librustc_mir/borrow_check/diagnostics/mod.rs
+++ b/src/librustc_mir/borrow_check/diagnostics/mod.rs
@@ -202,7 +202,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                 if self.body.local_decls[local].is_ref_to_static() =>
             {
                 let local_info = &self.body.local_decls[local].local_info;
-                if let LocalInfo::StaticRef { def_id, .. } = *local_info {
+                if let Some(box LocalInfo::StaticRef { def_id, .. }) = *local_info {
                     buf.push_str(&self.infcx.tcx.item_name(def_id).as_str());
                 } else {
                     unreachable!();
diff --git a/src/librustc_mir/borrow_check/diagnostics/move_errors.rs b/src/librustc_mir/borrow_check/diagnostics/move_errors.rs
index 457e263a466..ddaf78626f2 100644
--- a/src/librustc_mir/borrow_check/diagnostics/move_errors.rs
+++ b/src/librustc_mir/borrow_check/diagnostics/move_errors.rs
@@ -103,14 +103,14 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                         //
                         // opt_match_place is None for let [mut] x = ... statements,
                         // whether or not the right-hand side is a place expression
-                        if let LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(
+                        if let Some(box LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(
                             VarBindingForm {
                                 opt_match_place: Some((opt_match_place, match_span)),
                                 binding_mode: _,
                                 opt_ty_info: _,
                                 pat_span: _,
                             },
-                        ))) = local_decl.local_info
+                        )))) = local_decl.local_info
                         {
                             let stmt_source_info = self.body.source_info(location);
                             self.append_binding_error(
@@ -482,10 +482,10 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
         let mut suggestions: Vec<(Span, &str, String)> = Vec::new();
         for local in binds_to {
             let bind_to = &self.body.local_decls[*local];
-            if let LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(VarBindingForm {
+            if let Some(box LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(VarBindingForm {
                 pat_span,
                 ..
-            }))) = bind_to.local_info
+            })))) = bind_to.local_info
             {
                 if let Ok(pat_snippet) = self.infcx.tcx.sess.source_map().span_to_snippet(pat_span)
                 {
diff --git a/src/librustc_mir/borrow_check/diagnostics/mutability_errors.rs b/src/librustc_mir/borrow_check/diagnostics/mutability_errors.rs
index 1a4876db0de..402eac47c46 100644
--- a/src/librustc_mir/borrow_check/diagnostics/mutability_errors.rs
+++ b/src/librustc_mir/borrow_check/diagnostics/mutability_errors.rs
@@ -85,7 +85,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                 } else {
                     item_msg = format!("`{}`", access_place_desc.unwrap());
                     let local_info = &self.body.local_decls[local].local_info;
-                    if let LocalInfo::StaticRef { def_id, .. } = *local_info {
+                    if let Some(box LocalInfo::StaticRef { def_id, .. }) = *local_info {
                         let static_name = &self.infcx.tcx.item_name(def_id);
                         reason = format!(", as `{}` is an immutable static item", static_name);
                     } else {
@@ -216,9 +216,9 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                         .local_decls
                         .get(local)
                         .map(|local_decl| {
-                            if let LocalInfo::User(ClearCrossCrate::Set(
+                            if let Some(box LocalInfo::User(ClearCrossCrate::Set(
                                 mir::BindingForm::ImplicitSelf(kind),
-                            )) = local_decl.local_info
+                            ))) = local_decl.local_info
                             {
                                 // Check if the user variable is a `&mut self` and we can therefore
                                 // suggest removing the `&mut`.
@@ -340,8 +340,8 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
 
                 match self.local_names[local] {
                     Some(name) if !local_decl.from_compiler_desugaring() => {
-                        let label = match local_decl.local_info {
-                            LocalInfo::User(ClearCrossCrate::Set(
+                        let label = match local_decl.local_info.as_ref().unwrap() {
+                            box LocalInfo::User(ClearCrossCrate::Set(
                                 mir::BindingForm::ImplicitSelf(_),
                             )) => {
                                 let (span, suggestion) =
@@ -349,7 +349,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                                 Some((true, span, suggestion))
                             }
 
-                            LocalInfo::User(ClearCrossCrate::Set(mir::BindingForm::Var(
+                            box LocalInfo::User(ClearCrossCrate::Set(mir::BindingForm::Var(
                                 mir::VarBindingForm {
                                     binding_mode: ty::BindingMode::BindByValue(_),
                                     opt_ty_info,
@@ -381,14 +381,14 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                                             self.infcx.tcx,
                                             local_decl,
                                             opt_assignment_rhs_span,
-                                            opt_ty_info,
+                                            *opt_ty_info,
                                         );
                                         Some((true, span, suggestion))
                                     }
                                 }
                             }
 
-                            LocalInfo::User(ClearCrossCrate::Set(mir::BindingForm::Var(
+                            box LocalInfo::User(ClearCrossCrate::Set(mir::BindingForm::Var(
                                 mir::VarBindingForm {
                                     binding_mode: ty::BindingMode::BindByReference(_),
                                     ..
@@ -399,7 +399,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                                     .map(|replacement| (true, pattern_span, replacement))
                             }
 
-                            LocalInfo::User(ClearCrossCrate::Clear) => {
+                            box LocalInfo::User(ClearCrossCrate::Clear) => {
                                 bug!("saw cleared local state")
                             }
 
diff --git a/src/librustc_mir/transform/check_consts/validation.rs b/src/librustc_mir/transform/check_consts/validation.rs
index 3fd9131d5db..10cf47d47ff 100644
--- a/src/librustc_mir/transform/check_consts/validation.rs
+++ b/src/librustc_mir/transform/check_consts/validation.rs
@@ -456,7 +456,7 @@ impl Visitor<'tcx> for Validator<'mir, 'tcx> {
                     if proj_base.is_empty() {
                         if let (local, []) = (place_local, proj_base) {
                             let decl = &self.body.local_decls[local];
-                            if let LocalInfo::StaticRef { def_id, .. } = decl.local_info {
+                            if let Some(box LocalInfo::StaticRef { def_id, .. }) = decl.local_info {
                                 let span = decl.source_info.span;
                                 self.check_static(def_id, span);
                                 return;
diff --git a/src/librustc_mir/transform/check_unsafety.rs b/src/librustc_mir/transform/check_unsafety.rs
index 35726dde602..0bd9b3e1b20 100644
--- a/src/librustc_mir/transform/check_unsafety.rs
+++ b/src/librustc_mir/transform/check_unsafety.rs
@@ -218,7 +218,7 @@ impl<'a, 'tcx> Visitor<'tcx> for UnsafetyChecker<'a, 'tcx> {
             if let [] = proj_base {
                 let decl = &self.body.local_decls[place.local];
                 if decl.internal {
-                    if let LocalInfo::StaticRef { def_id, .. } = decl.local_info {
+                    if let Some(box LocalInfo::StaticRef { def_id, .. }) = decl.local_info {
                         if self.tcx.is_mutable_static(def_id) {
                             self.require_unsafe(
                                 "use of mutable static",
diff --git a/src/librustc_mir_build/build/expr/as_temp.rs b/src/librustc_mir_build/build/expr/as_temp.rs
index 16ca2057584..50bd5a73e25 100644
--- a/src/librustc_mir_build/build/expr/as_temp.rs
+++ b/src/librustc_mir_build/build/expr/as_temp.rs
@@ -61,7 +61,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             if let ExprKind::StaticRef { def_id, .. } = expr.kind {
                 let is_thread_local = this.hir.tcx().is_thread_local_static(def_id);
                 local_decl.internal = true;
-                local_decl.local_info = LocalInfo::StaticRef { def_id, is_thread_local };
+                local_decl.local_info = Some(box LocalInfo::StaticRef { def_id, is_thread_local });
             }
             this.local_decls.push(local_decl)
         };
diff --git a/src/librustc_mir_build/build/matches/mod.rs b/src/librustc_mir_build/build/matches/mod.rs
index 03fdd2ed8f1..7812848e926 100644
--- a/src/librustc_mir_build/build/matches/mod.rs
+++ b/src/librustc_mir_build/build/matches/mod.rs
@@ -470,9 +470,9 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 for binding in &candidate_ref.bindings {
                     let local = self.var_local_id(binding.var_id, OutsideGuard);
 
-                    if let LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(
+                    if let Some(box LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(
                         VarBindingForm { opt_match_place: Some((ref mut match_place, _)), .. },
-                    ))) = self.local_decls[local].local_info
+                    )))) = self.local_decls[local].local_info
                     {
                         *match_place = Some(initializer);
                     } else {
@@ -1953,7 +1953,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             source_info,
             internal: false,
             is_block_tail: None,
-            local_info: LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(VarBindingForm {
+            local_info: Some(box LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(VarBindingForm {
                 binding_mode,
                 // hypothetically, `visit_bindings` could try to unzip
                 // an outermost hir::Ty as we descend, matching up
@@ -1962,7 +1962,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 opt_ty_info: None,
                 opt_match_place,
                 pat_span,
-            }))),
+            })))),
         };
         let for_arm_body = self.local_decls.push(local);
         self.var_debug_info.push(VarDebugInfo {
@@ -1980,7 +1980,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 source_info,
                 internal: false,
                 is_block_tail: None,
-                local_info: LocalInfo::User(ClearCrossCrate::Set(BindingForm::RefForGuard)),
+                local_info: Some(box LocalInfo::User(ClearCrossCrate::Set(BindingForm::RefForGuard))),
             });
             self.var_debug_info.push(VarDebugInfo {
                 name,
diff --git a/src/librustc_mir_build/build/mod.rs b/src/librustc_mir_build/build/mod.rs
index a668cb86910..6c61c27c4ed 100644
--- a/src/librustc_mir_build/build/mod.rs
+++ b/src/librustc_mir_build/build/mod.rs
@@ -909,17 +909,17 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                         self.local_decls[local].mutability = mutability;
                         self.local_decls[local].source_info.scope = self.source_scope;
                         self.local_decls[local].local_info = if let Some(kind) = self_binding {
-                            LocalInfo::User(ClearCrossCrate::Set(BindingForm::ImplicitSelf(*kind)))
+                            Some(box LocalInfo::User(ClearCrossCrate::Set(BindingForm::ImplicitSelf(*kind))))
                         } else {
                             let binding_mode = ty::BindingMode::BindByValue(mutability);
-                            LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(
+                            Some(box LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(
                                 VarBindingForm {
                                     binding_mode,
                                     opt_ty_info,
                                     opt_match_place: Some((Some(place), span)),
                                     pat_span: span,
                                 },
-                            )))
+                            ))))
                         };
                         self.var_indices.insert(var, LocalsForNode::One(local));
                     }