From e221b24cb6d0a5331bfa04a546cea16f22c41988 Mon Sep 17 00:00:00 2001
From: Nicholas Nethercote <nnethercote@mozilla.com>
Date: Mon, 24 Sep 2018 12:13:23 +1000
Subject: [PATCH] Shrink StatementKind::InlineAsm.

This shrinks StatementKind from 64 bytes to 48 bytes on 64-bit.
---
 src/librustc/mir/mod.rs                           |  4 ++--
 src/librustc/ty/structural_impls.rs               | 10 ++++++++++
 src/librustc_mir/borrow_check/mod.rs              |  4 ++--
 src/librustc_mir/borrow_check/nll/invalidation.rs |  4 ++--
 src/librustc_mir/build/expr/stmt.rs               |  6 ++++--
 src/librustc_mir/dataflow/move_paths/builder.rs   |  2 +-
 6 files changed, 21 insertions(+), 9 deletions(-)

diff --git a/src/librustc/mir/mod.rs b/src/librustc/mir/mod.rs
index ab1304acf2a5..6e9f5a7a215f 100644
--- a/src/librustc/mir/mod.rs
+++ b/src/librustc/mir/mod.rs
@@ -1633,8 +1633,8 @@ pub enum StatementKind<'tcx> {
     /// Execute a piece of inline Assembly.
     InlineAsm {
         asm: Box<InlineAsm>,
-        outputs: Vec<Place<'tcx>>,
-        inputs: Vec<Operand<'tcx>>,
+        outputs: Box<[Place<'tcx>]>,
+        inputs: Box<[Operand<'tcx>]>,
     },
 
     /// Assert the given places to be valid inhabitants of their type.  These statements are
diff --git a/src/librustc/ty/structural_impls.rs b/src/librustc/ty/structural_impls.rs
index bd9dfc6b8551..aab268c07c4f 100644
--- a/src/librustc/ty/structural_impls.rs
+++ b/src/librustc/ty/structural_impls.rs
@@ -720,6 +720,16 @@ impl<'tcx, T: TypeFoldable<'tcx>> TypeFoldable<'tcx> for Vec<T> {
     }
 }
 
+impl<'tcx, T: TypeFoldable<'tcx>> TypeFoldable<'tcx> for Box<[T]> {
+    fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
+        self.iter().map(|t| t.fold_with(folder)).collect::<Vec<_>>().into_boxed_slice()
+    }
+
+    fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
+        self.iter().any(|t| t.visit_with(visitor))
+    }
+}
+
 impl<'tcx, T:TypeFoldable<'tcx>> TypeFoldable<'tcx> for ty::Binder<T> {
     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
         self.map_bound_ref(|ty| ty.fold_with(folder))
diff --git a/src/librustc_mir/borrow_check/mod.rs b/src/librustc_mir/borrow_check/mod.rs
index 06884875598d..ae0a06294bf5 100644
--- a/src/librustc_mir/borrow_check/mod.rs
+++ b/src/librustc_mir/borrow_check/mod.rs
@@ -528,7 +528,7 @@ impl<'cx, 'gcx, 'tcx> DataflowResultsConsumer<'cx, 'tcx> for MirBorrowckCtxt<'cx
                 ref inputs,
             } => {
                 let context = ContextKind::InlineAsm.new(location);
-                for (o, output) in asm.outputs.iter().zip(outputs) {
+                for (o, output) in asm.outputs.iter().zip(outputs.iter()) {
                     if o.is_indirect {
                         // FIXME(eddyb) indirect inline asm outputs should
                         // be encoeded through MIR place derefs instead.
@@ -555,7 +555,7 @@ impl<'cx, 'gcx, 'tcx> DataflowResultsConsumer<'cx, 'tcx> for MirBorrowckCtxt<'cx
                         );
                     }
                 }
-                for input in inputs {
+                for input in inputs.iter() {
                     self.consume_operand(context, (input, span), flow_state);
                 }
             }
diff --git a/src/librustc_mir/borrow_check/nll/invalidation.rs b/src/librustc_mir/borrow_check/nll/invalidation.rs
index cd760746c125..b755482b49ae 100644
--- a/src/librustc_mir/borrow_check/nll/invalidation.rs
+++ b/src/librustc_mir/borrow_check/nll/invalidation.rs
@@ -118,7 +118,7 @@ impl<'cg, 'cx, 'tcx, 'gcx> Visitor<'tcx> for InvalidationGenerator<'cg, 'cx, 'tc
                 ref inputs,
             } => {
                 let context = ContextKind::InlineAsm.new(location);
-                for (o, output) in asm.outputs.iter().zip(outputs) {
+                for (o, output) in asm.outputs.iter().zip(outputs.iter()) {
                     if o.is_indirect {
                         // FIXME(eddyb) indirect inline asm outputs should
                         // be encoeded through MIR place derefs instead.
@@ -137,7 +137,7 @@ impl<'cg, 'cx, 'tcx, 'gcx> Visitor<'tcx> for InvalidationGenerator<'cg, 'cx, 'tc
                         );
                     }
                 }
-                for input in inputs {
+                for input in inputs.iter() {
                     self.consume_operand(context, input);
                 }
             }
diff --git a/src/librustc_mir/build/expr/stmt.rs b/src/librustc_mir/build/expr/stmt.rs
index 0086cff46e53..32f09599ace8 100644
--- a/src/librustc_mir/build/expr/stmt.rs
+++ b/src/librustc_mir/build/expr/stmt.rs
@@ -143,11 +143,13 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                 let outputs = outputs
                     .into_iter()
                     .map(|output| unpack!(block = this.as_place(block, output)))
-                    .collect();
+                    .collect::<Vec<_>>()
+                    .into_boxed_slice();
                 let inputs = inputs
                     .into_iter()
                     .map(|input| unpack!(block = this.as_local_operand(block, input)))
-                    .collect();
+                    .collect::<Vec<_>>()
+                    .into_boxed_slice();
                 this.cfg.push(
                     block,
                     Statement {
diff --git a/src/librustc_mir/dataflow/move_paths/builder.rs b/src/librustc_mir/dataflow/move_paths/builder.rs
index 63adcb5132a7..2884b15ca47d 100644
--- a/src/librustc_mir/dataflow/move_paths/builder.rs
+++ b/src/librustc_mir/dataflow/move_paths/builder.rs
@@ -290,7 +290,7 @@ impl<'b, 'a, 'gcx, 'tcx> Gatherer<'b, 'a, 'gcx, 'tcx> {
                         self.gather_init(output, InitKind::Deep);
                     }
                 }
-                for input in inputs {
+                for input in inputs.iter() {
                     self.gather_operand(input);
                 }
             }