From b2779d85962b520bb8718b371e7264aa44827058 Mon Sep 17 00:00:00 2001 From: Jonas Schievink Date: Tue, 10 Mar 2020 00:17:33 +0100 Subject: [PATCH] Use smaller discriminants for generators --- src/librustc/ty/layout.rs | 15 +++++++++------ .../ui/async-await/async-fn-size-moved-locals.rs | 10 +++++----- .../ui/async-await/async-fn-size-uninit-locals.rs | 10 +++++----- src/test/ui/async-await/async-fn-size.rs | 14 +++++++------- src/test/ui/generator/size-moved-locals.rs | 10 +++++----- 5 files changed, 31 insertions(+), 28 deletions(-) diff --git a/src/librustc/ty/layout.rs b/src/librustc/ty/layout.rs index dedb3035cedb3..f5ef9bda0eeda 100644 --- a/src/librustc/ty/layout.rs +++ b/src/librustc/ty/layout.rs @@ -1409,12 +1409,15 @@ impl<'tcx> LayoutCx<'tcx, TyCtxt<'tcx>> { // locals as part of the prefix. We compute the layout of all of // these fields at once to get optimal packing. let discr_index = substs.as_generator().prefix_tys(def_id, tcx).count(); - // FIXME(eddyb) set the correct vaidity range for the discriminant. - let discr_layout = self.layout_of(substs.as_generator().discr_ty(tcx))?; - let discr = match &discr_layout.abi { - Abi::Scalar(s) => s.clone(), - _ => bug!(), - }; + + // `info.variant_fields` already accounts for the reserved variants, so no need to add them. + let max_discr = (info.variant_fields.len() - 1) as u128; + let discr_int = Integer::fit_unsigned(max_discr); + let discr_int_ty = discr_int.to_ty(tcx, false); + let discr = Scalar { value: Primitive::Int(discr_int, false), valid_range: 0..=max_discr }; + let discr_layout = self.tcx.intern_layout(LayoutDetails::scalar(self, discr.clone())); + let discr_layout = TyLayout { ty: discr_int_ty, details: discr_layout }; + let promoted_layouts = ineligible_locals .iter() .map(|local| subst_field(info.field_tys[local])) diff --git a/src/test/ui/async-await/async-fn-size-moved-locals.rs b/src/test/ui/async-await/async-fn-size-moved-locals.rs index 4a413381aa300..636fafc2bc44a 100644 --- a/src/test/ui/async-await/async-fn-size-moved-locals.rs +++ b/src/test/ui/async-await/async-fn-size-moved-locals.rs @@ -110,9 +110,9 @@ async fn mixed_sizes() { } fn main() { - assert_eq!(1028, std::mem::size_of_val(&single())); - assert_eq!(1032, std::mem::size_of_val(&single_with_noop())); - assert_eq!(3084, std::mem::size_of_val(&joined())); - assert_eq!(3084, std::mem::size_of_val(&joined_with_noop())); - assert_eq!(7188, std::mem::size_of_val(&mixed_sizes())); + assert_eq!(1025, std::mem::size_of_val(&single())); + assert_eq!(1026, std::mem::size_of_val(&single_with_noop())); + assert_eq!(3078, std::mem::size_of_val(&joined())); + assert_eq!(3079, std::mem::size_of_val(&joined_with_noop())); + assert_eq!(7181, std::mem::size_of_val(&mixed_sizes())); } diff --git a/src/test/ui/async-await/async-fn-size-uninit-locals.rs b/src/test/ui/async-await/async-fn-size-uninit-locals.rs index 0558084f4f8a3..d5d7b3fc3f0bd 100644 --- a/src/test/ui/async-await/async-fn-size-uninit-locals.rs +++ b/src/test/ui/async-await/async-fn-size-uninit-locals.rs @@ -95,9 +95,9 @@ async fn join_retval() -> Joiner { } fn main() { - assert_eq!(8, std::mem::size_of_val(&single())); - assert_eq!(12, std::mem::size_of_val(&single_with_noop())); - assert_eq!(3084, std::mem::size_of_val(&joined())); - assert_eq!(3084, std::mem::size_of_val(&joined_with_noop())); - assert_eq!(3080, std::mem::size_of_val(&join_retval())); + assert_eq!(2, std::mem::size_of_val(&single())); + assert_eq!(3, std::mem::size_of_val(&single_with_noop())); + assert_eq!(3078, std::mem::size_of_val(&joined())); + assert_eq!(3078, std::mem::size_of_val(&joined_with_noop())); + assert_eq!(3074, std::mem::size_of_val(&join_retval())); } diff --git a/src/test/ui/async-await/async-fn-size.rs b/src/test/ui/async-await/async-fn-size.rs index b313992db4ecb..0c1f3636446c9 100644 --- a/src/test/ui/async-await/async-fn-size.rs +++ b/src/test/ui/async-await/async-fn-size.rs @@ -86,13 +86,13 @@ async fn await3_level5() -> u8 { fn main() { assert_eq!(2, std::mem::size_of_val(&base())); - assert_eq!(8, std::mem::size_of_val(&await1_level1())); - assert_eq!(12, std::mem::size_of_val(&await2_level1())); - assert_eq!(12, std::mem::size_of_val(&await3_level1())); - assert_eq!(24, std::mem::size_of_val(&await3_level2())); - assert_eq!(36, std::mem::size_of_val(&await3_level3())); - assert_eq!(48, std::mem::size_of_val(&await3_level4())); - assert_eq!(60, std::mem::size_of_val(&await3_level5())); + assert_eq!(3, std::mem::size_of_val(&await1_level1())); + assert_eq!(4, std::mem::size_of_val(&await2_level1())); + assert_eq!(5, std::mem::size_of_val(&await3_level1())); + assert_eq!(8, std::mem::size_of_val(&await3_level2())); + assert_eq!(11, std::mem::size_of_val(&await3_level3())); + assert_eq!(14, std::mem::size_of_val(&await3_level4())); + assert_eq!(17, std::mem::size_of_val(&await3_level5())); assert_eq!(1, wait(base())); assert_eq!(1, wait(await1_level1())); diff --git a/src/test/ui/generator/size-moved-locals.rs b/src/test/ui/generator/size-moved-locals.rs index 2864fbb2f3c8d..74c60d98154dd 100644 --- a/src/test/ui/generator/size-moved-locals.rs +++ b/src/test/ui/generator/size-moved-locals.rs @@ -58,7 +58,7 @@ fn overlap_move_points() -> impl Generator { } } -fn overlap_x_and_y() -> impl Generator{ +fn overlap_x_and_y() -> impl Generator { static || { let x = Foo([0; FOO_SIZE]); yield; @@ -70,8 +70,8 @@ fn overlap_x_and_y() -> impl Generator{ } fn main() { - assert_eq!(1028, std::mem::size_of_val(&move_before_yield())); - assert_eq!(1032, std::mem::size_of_val(&move_before_yield_with_noop())); - assert_eq!(2056, std::mem::size_of_val(&overlap_move_points())); - assert_eq!(1032, std::mem::size_of_val(&overlap_x_and_y())); + assert_eq!(1025, std::mem::size_of_val(&move_before_yield())); + assert_eq!(1026, std::mem::size_of_val(&move_before_yield_with_noop())); + assert_eq!(2051, std::mem::size_of_val(&overlap_move_points())); + assert_eq!(1026, std::mem::size_of_val(&overlap_x_and_y())); }