Auto merge of #41926 - arielb1:box-mir, r=eddyb

box large variants in MIR

Operand: 72 -> 24 B
Statement: 192 -> 96 B
Terminator: 256 -> 112 B
librustc translation memory usage: 1795 -> 1669 MB

next step would be interning lvalues, I suppose?

cc #36799 (@urschrei - does ostn15_phf compile with this PR?)

r? @eddyb

src/librustc/mir/mod.rs

@@ -799,7 +799,7 @@ pub enum StatementKind<'tcx> {
     StorageDead(Lvalue<'tcx>),
 
     InlineAsm {
-        asm: InlineAsm,
+        asm: Box<InlineAsm>,
         outputs: Vec<Lvalue<'tcx>>,
         inputs: Vec<Operand<'tcx>>
     },
@@ -995,7 +995,7 @@ pub struct VisibilityScopeData {
 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable)]
 pub enum Operand<'tcx> {
     Consume(Lvalue<'tcx>),
-    Constant(Constant<'tcx>),
+    Constant(Box<Constant<'tcx>>),
 }
 
 impl<'tcx> Debug for Operand<'tcx> {
@@ -1015,7 +1015,7 @@ impl<'tcx> Operand<'tcx> {
         substs: &'tcx Substs<'tcx>,
         span: Span,
     ) -> Self {
-        Operand::Constant(Constant {
+        Operand::Constant(box Constant {
             span: span,
             ty: tcx.type_of(def_id).subst(tcx, substs),
             literal: Literal::Value { value: ConstVal::Function(def_id, substs) },
@@ -1062,7 +1062,7 @@ pub enum Rvalue<'tcx> {
     /// ..., y: ... }` from `dest.x = ...; dest.y = ...;` in the case
     /// that `Foo` has a destructor. These rvalues can be optimized
     /// away after type-checking and before lowering.
-    Aggregate(AggregateKind<'tcx>, Vec<Operand<'tcx>>),
+    Aggregate(Box<AggregateKind<'tcx>>, Vec<Operand<'tcx>>),
 }
 
 #[derive(Clone, Copy, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
@@ -1185,7 +1185,7 @@ impl<'tcx> Debug for Rvalue<'tcx> {
                     tuple_fmt.finish()
                 }
 
-                match *kind {
+                match **kind {
                     AggregateKind::Array(_) => write!(fmt, "{:?}", lvs),
 
                     AggregateKind::Tuple => {
@@ -1603,7 +1603,7 @@ impl<'tcx> TypeFoldable<'tcx> for Rvalue<'tcx> {
             Discriminant(ref lval) => Discriminant(lval.fold_with(folder)),
             Box(ty) => Box(ty.fold_with(folder)),
             Aggregate(ref kind, ref fields) => {
-                let kind = match *kind {
+                let kind = box match **kind {
                     AggregateKind::Array(ty) => AggregateKind::Array(ty.fold_with(folder)),
                     AggregateKind::Tuple => AggregateKind::Tuple,
                     AggregateKind::Adt(def, v, substs, n) =>
@@ -1631,7 +1631,7 @@ impl<'tcx> TypeFoldable<'tcx> for Rvalue<'tcx> {
             Discriminant(ref lval) => lval.visit_with(visitor),
             Box(ty) => ty.visit_with(visitor),
             Aggregate(ref kind, ref fields) => {
-                (match *kind {
+                (match **kind {
                     AggregateKind::Array(ty) => ty.visit_with(visitor),
                     AggregateKind::Tuple => false,
                     AggregateKind::Adt(_, _, substs, _) => substs.visit_with(visitor),

src/librustc/mir/tcx.rs

@@ -183,7 +183,7 @@ impl<'tcx> Rvalue<'tcx> {
                 tcx.mk_box(t)
             }
             Rvalue::Aggregate(ref ak, ref ops) => {
-                match *ak {
+                match **ak {
                     AggregateKind::Array(ty) => {
                         tcx.mk_array(ty, ops.len())
                     }

src/librustc/mir/visit.rs

@@ -515,6 +515,7 @@ macro_rules! make_mir_visitor {
 
                     Rvalue::Aggregate(ref $($mutability)* kind,
                                       ref $($mutability)* operands) => {
+                        let kind = &$($mutability)* **kind;
                         match *kind {
                             AggregateKind::Array(ref $($mutability)* ty) => {
                                 self.visit_ty(ty);

src/librustc_borrowck/borrowck/mir/elaborate_drops.rs

@@ -517,11 +517,11 @@ impl<'b, 'tcx> ElaborateDropsCtxt<'b, 'tcx> {
     }
 
     fn constant_bool(&self, span: Span, val: bool) -> Rvalue<'tcx> {
-        Rvalue::Use(Operand::Constant(Constant {
+        Rvalue::Use(Operand::Constant(Box::new(Constant {
             span: span,
             ty: self.tcx.types.bool,
             literal: Literal::Value { value: ConstVal::Bool(val) }
-        }))
+        })))
     }
 
     fn set_drop_flag(&mut self, loc: Location, path: MovePathIndex, val: DropFlagState) {

src/librustc_mir/build/cfg.rs

@@ -60,15 +60,15 @@ impl<'tcx> CFG<'tcx> {
                                 temp: &Lvalue<'tcx>,
                                 constant: Constant<'tcx>) {
         self.push_assign(block, source_info, temp,
-                         Rvalue::Use(Operand::Constant(constant)));
+                         Rvalue::Use(Operand::Constant(box constant)));
     }
 
     pub fn push_assign_unit(&mut self,
                             block: BasicBlock,
                             source_info: SourceInfo,
                             lvalue: &Lvalue<'tcx>) {
         self.push_assign(block, source_info, lvalue, Rvalue::Aggregate(
-            AggregateKind::Tuple, vec![]
+            box AggregateKind::Tuple, vec![]
         ));
     }
 

src/librustc_mir/build/expr/as_operand.rs

@@ -66,7 +66,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
         match category {
             Category::Constant => {
                 let constant = this.as_constant(expr);
-                block.and(Operand::Constant(constant))
+                block.and(Operand::Constant(box constant))
             }
             Category::Lvalue |
             Category::Rvalue(..) => {

src/librustc_mir/build/expr/as_rvalue.rs

@@ -166,7 +166,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                           .map(|f| unpack!(block = this.as_operand(block, scope, f)))
                           .collect();
 
-                block.and(Rvalue::Aggregate(AggregateKind::Array(el_ty), fields))
+                block.and(Rvalue::Aggregate(box AggregateKind::Array(el_ty), fields))
             }
             ExprKind::Tuple { fields } => { // see (*) above
                 // first process the set of fields
@@ -175,14 +175,14 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                           .map(|f| unpack!(block = this.as_operand(block, scope, f)))
                           .collect();
 
-                block.and(Rvalue::Aggregate(AggregateKind::Tuple, fields))
+                block.and(Rvalue::Aggregate(box AggregateKind::Tuple, fields))
             }
             ExprKind::Closure { closure_id, substs, upvars } => { // see (*) above
                 let upvars =
                     upvars.into_iter()
                           .map(|upvar| unpack!(block = this.as_operand(block, scope, upvar)))
                           .collect();
-                block.and(Rvalue::Aggregate(AggregateKind::Closure(closure_id, substs), upvars))
+                block.and(Rvalue::Aggregate(box AggregateKind::Closure(closure_id, substs), upvars))
             }
             ExprKind::Adt {
                 adt_def, variant_index, substs, fields, base
@@ -215,7 +215,8 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                     field_names.iter().filter_map(|n| fields_map.get(n).cloned()).collect()
                 };
 
-                let adt = AggregateKind::Adt(adt_def, variant_index, substs, active_field_index);
+                let adt =
+                    box AggregateKind::Adt(adt_def, variant_index, substs, active_field_index);
                 block.and(Rvalue::Aggregate(adt, fields))
             }
             ExprKind::Assign { .. } |

src/librustc_mir/build/expr/stmt.rs

@@ -129,7 +129,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                 this.cfg.push(block, Statement {
                     source_info: source_info,
                     kind: StatementKind::InlineAsm {
-                        asm: asm.clone(),
+                        asm: box asm.clone(),
                         outputs: outputs,
                         inputs: inputs
                     },

src/librustc_mir/build/matches/test.rs

@@ -308,7 +308,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                     let eq_block = self.cfg.start_new_block();
                     let cleanup = self.diverge_cleanup();
                     self.cfg.terminate(block, source_info, TerminatorKind::Call {
-                        func: Operand::Constant(Constant {
+                        func: Operand::Constant(box Constant {
                             span: test.span,
                             ty: mty,
                             literal: method

src/librustc_mir/build/misc.rs

@@ -40,7 +40,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                            ty: Ty<'tcx>,
                            literal: Literal<'tcx>)
                            -> Operand<'tcx> {
-        let constant = Constant {
+        let constant = box Constant {
             span: span,
             ty: ty,
             literal: literal,
@@ -49,7 +49,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
     }
 
     pub fn unit_rvalue(&mut self) -> Rvalue<'tcx> {
-        Rvalue::Aggregate(AggregateKind::Tuple, vec![])
+        Rvalue::Aggregate(box AggregateKind::Tuple, vec![])
     }
 
     // Returns a zero literal operand for the appropriate type, works for

src/librustc_mir/build/scope.rs

@@ -786,7 +786,7 @@ fn build_free<'a, 'gcx, 'tcx>(tcx: TyCtxt<'a, 'gcx, 'tcx>,
     let free_func = tcx.require_lang_item(lang_items::BoxFreeFnLangItem);
     let substs = tcx.intern_substs(&[Kind::from(data.item_ty)]);
     TerminatorKind::Call {
-        func: Operand::Constant(Constant {
+        func: Operand::Constant(box Constant {
             span: data.span,
             ty: tcx.type_of(free_func).subst(tcx, substs),
             literal: Literal::Value {

src/librustc_mir/shim.rs

@@ -323,7 +323,7 @@ fn build_call_shim<'a, 'tcx>(tcx: ty::TyCtxt<'a, 'tcx, 'tcx>,
     let (callee, mut args) = match call_kind {
         CallKind::Indirect => (rcvr, vec![]),
         CallKind::Direct(def_id) => (
-            Operand::Constant(Constant {
+            Operand::Constant(box Constant {
                 span: span,
                 ty: tcx.type_of(def_id).subst(tcx, param_env.free_substs),
                 literal: Literal::Value {
@@ -449,7 +449,7 @@ pub fn build_adt_ctor<'a, 'gcx, 'tcx>(infcx: &infer::InferCtxt<'a, 'gcx, 'tcx>,
             kind: StatementKind::Assign(
                 Lvalue::Local(RETURN_POINTER),
                 Rvalue::Aggregate(
-                    AggregateKind::Adt(adt_def, variant_no, substs, None),
+                    box AggregateKind::Adt(adt_def, variant_no, substs, None),
                     (1..sig.inputs().len()+1).map(|i| {
                         Operand::Consume(Lvalue::Local(Local::new(i)))
                     }).collect()

src/librustc_mir/transform/copy_prop.rs

@@ -316,7 +316,7 @@ impl<'tcx> MutVisitor<'tcx> for ConstantPropagationVisitor<'tcx> {
             _ => return,
         }
 
-        *operand = Operand::Constant(self.constant.clone());
+        *operand = Operand::Constant(box self.constant.clone());
         self.uses_replaced += 1
     }
 }

src/librustc_mir/transform/deaggregator.rs

@@ -49,8 +49,8 @@ impl MirPass for Deaggregator {
                     &Rvalue::Aggregate(ref agg_kind, ref operands) => (agg_kind, operands),
                     _ => span_bug!(src_info.span, "expected aggregate, not {:?}", rhs),
                 };
-                let (adt_def, variant, substs) = match agg_kind {
-                    &AggregateKind::Adt(adt_def, variant, substs, None)
+                let (adt_def, variant, substs) = match **agg_kind {
+                    AggregateKind::Adt(adt_def, variant, substs, None)
                         => (adt_def, variant, substs),
                     _ => span_bug!(src_info.span, "expected struct, not {:?}", rhs),
                 };
@@ -114,8 +114,8 @@ fn get_aggregate_statement_index<'a, 'tcx, 'b>(start: usize,
             &Rvalue::Aggregate(ref kind, ref operands) => (kind, operands),
             _ => continue,
         };
-        let (adt_def, variant) = match kind {
-            &AggregateKind::Adt(adt_def, variant, _, None) => (adt_def, variant),
+        let (adt_def, variant) = match **kind {
+            AggregateKind::Adt(adt_def, variant, _, None) => (adt_def, variant),
             _ => continue,
         };
         if operands.len() == 0 {

src/librustc_mir/transform/promote_consts.rs

@@ -230,7 +230,7 @@ impl<'a, 'tcx> Promoter<'a, 'tcx> {
                 (if self.keep_original {
                     rhs.clone()
                 } else {
-                    let unit = Rvalue::Aggregate(AggregateKind::Tuple, vec![]);
+                    let unit = Rvalue::Aggregate(box AggregateKind::Tuple, vec![]);
                     mem::replace(rhs, unit)
                 }, statement.source_info)
             };
@@ -288,7 +288,7 @@ impl<'a, 'tcx> Promoter<'a, 'tcx> {
 
     fn promote_candidate(mut self, candidate: Candidate) {
         let span = self.promoted.span;
-        let new_operand = Operand::Constant(Constant {
+        let new_operand = Operand::Constant(box Constant {
             span: span,
             ty: self.promoted.return_ty,
             literal: Literal::Promoted {

src/librustc_mir/transform/qualify_consts.rs

@@ -730,7 +730,7 @@ impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> {
             }
 
             Rvalue::Aggregate(ref kind, _) => {
-                if let AggregateKind::Adt(def, ..) = *kind {
+                if let AggregateKind::Adt(def, ..) = **kind {
                     if def.has_dtor(self.tcx) {
                         self.add(Qualif::NEEDS_DROP);
                         self.deny_drop();

src/librustc_mir/transform/simplify_branches.rs

@@ -37,7 +37,7 @@ impl MirPass for SimplifyBranches {
         for block in mir.basic_blocks_mut() {
             let terminator = block.terminator_mut();
             terminator.kind = match terminator.kind {
-                TerminatorKind::SwitchInt { discr: Operand::Constant(Constant {
+                TerminatorKind::SwitchInt { discr: Operand::Constant(box Constant {
                     literal: Literal::Value { ref value }, ..
                 }), ref values, ref targets, .. } => {
                     if let Some(ref constint) = value.to_const_int() {
@@ -54,7 +54,7 @@ impl MirPass for SimplifyBranches {
                         continue
                     }
                 },
-                TerminatorKind::Assert { target, cond: Operand::Constant(Constant {
+                TerminatorKind::Assert { target, cond: Operand::Constant(box Constant {
                     literal: Literal::Value {
                         value: ConstVal::Bool(cond)
                     }, ..
@@ -66,4 +66,3 @@ impl MirPass for SimplifyBranches {
         }
     }
 }
-

src/librustc_mir/transform/type_check.rs

@@ -534,7 +534,7 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
 
     fn is_box_free(&self, operand: &Operand<'tcx>) -> bool {
         match operand {
-            &Operand::Constant(Constant {
+            &Operand::Constant(box Constant {
                 literal: Literal::Value {
                     value: ConstVal::Function(def_id, _), ..
                 }, ..

src/librustc_passes/mir_stats.rs

@@ -190,7 +190,7 @@ impl<'a, 'tcx> mir_visit::Visitor<'tcx> for StatCollector<'a, 'tcx> {
             Rvalue::Aggregate(ref kind, ref _operands) => {
                 // AggregateKind is not distinguished by visit API, so
                 // record it. (`super_rvalue` handles `_operands`.)
-                self.record(match *kind {
+                self.record(match **kind {
                     AggregateKind::Array(_) => "AggregateKind::Array",
                     AggregateKind::Tuple => "AggregateKind::Tuple",
                     AggregateKind::Adt(..) => "AggregateKind::Adt",

src/librustc_trans/mir/analyze.rs

@@ -108,7 +108,7 @@ impl<'mir, 'a, 'tcx> Visitor<'tcx> for LocalAnalyzer<'mir, 'a, 'tcx> {
                              location: Location) {
         match *kind {
             mir::TerminatorKind::Call {
-                func: mir::Operand::Constant(mir::Constant {
+                func: mir::Operand::Constant(box mir::Constant {
                     literal: Literal::Value {
                         value: ConstVal::Function(def_id, _), ..
                     }, ..

src/librustc_trans/mir/constant.rs

@@ -537,7 +537,7 @@ impl<'a, 'tcx> MirConstContext<'a, 'tcx> {
                 }
                 failure?;
 
-                match *kind {
+                match **kind {
                     mir::AggregateKind::Array(_) => {
                         self.const_array(dest_ty, &fields)
                     }

src/librustc_trans/mir/rvalue.rs

@@ -104,7 +104,7 @@ impl<'a, 'tcx> MirContext<'a, 'tcx> {
             }
 
             mir::Rvalue::Aggregate(ref kind, ref operands) => {
-                match *kind {
+                match **kind {
                     mir::AggregateKind::Adt(adt_def, variant_index, substs, active_field_index) => {
                         let discr = adt_def.discriminant_for_variant(bcx.tcx(), variant_index)
                            .to_u128_unchecked() as u64;