Rollup merge of #100003 - nnethercote:improve-size-assertions, r=lqd

Improve size assertions.

- For any file with four or more size assertions, move them into a
  separate module (as is already done for `hir.rs`).
- Add some more for AST nodes and THIR nodes.
- Put the `hir.rs` ones in alphabetical order.

r? `@lqd`

1 files changed, 16 insertions, 39 deletions

diff --git a/src/librustdoc/clean/types.rs b/src/librustdoc/clean/types.rs
index d022ce9696a..1a46d077f1b 100644
--- a/src/librustdoc/clean/types.rs
+++ b/src/librustdoc/clean/types.rs
@@ -122,10 +122,6 @@ pub(crate) struct Crate {
     pub(crate) external_traits: Rc<RefCell<FxHashMap<DefId, TraitWithExtraInfo>>>,
 }
 
-// `Crate` is frequently moved by-value. Make sure it doesn't unintentionally get bigger.
-#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
-rustc_data_structures::static_assert_size!(Crate, 72);
-
 impl Crate {
     pub(crate) fn name(&self, tcx: TyCtxt<'_>) -> Symbol {
         ExternalCrate::LOCAL.name(tcx)
@@ -389,10 +385,6 @@ impl fmt::Debug for Item {
     }
 }
 
-// `Item` is used a lot. Make sure it doesn't unintentionally get bigger.
-#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
-rustc_data_structures::static_assert_size!(Item, 56);
-
 pub(crate) fn rustc_span(def_id: DefId, tcx: TyCtxt<'_>) -> Span {
     Span::new(def_id.as_local().map_or_else(
         || tcx.def_span(def_id),
@@ -771,10 +763,6 @@ pub(crate) enum ItemKind {
     KeywordItem,
 }
 
-// `ItemKind` is an enum and large variants can bloat up memory usage even for smaller ones
-#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
-rustc_data_structures::static_assert_size!(ItemKind, 112);
-
 impl ItemKind {
     /// Some items contain others such as structs (for their fields) and Enums
     /// (for their variants). This method returns those contained items.
@@ -994,10 +982,6 @@ pub(crate) struct DocFragment {
     pub(crate) indent: usize,
 }
 
-// `DocFragment` is used a lot. Make sure it doesn't unintentionally get bigger.
-#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
-rustc_data_structures::static_assert_size!(DocFragment, 32);
-
 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
 pub(crate) enum DocFragmentKind {
     /// A doc fragment created from a `///` or `//!` doc comment.
@@ -1382,10 +1366,6 @@ pub(crate) struct GenericParamDef {
     pub(crate) kind: GenericParamDefKind,
 }
 
-// `GenericParamDef` is used in many places. Make sure it doesn't unintentionally get bigger.
-#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
-rustc_data_structures::static_assert_size!(GenericParamDef, 56);
-
 impl GenericParamDef {
     pub(crate) fn is_synthetic_type_param(&self) -> bool {
         match self.kind {
@@ -1590,10 +1570,6 @@ pub(crate) enum Type {
     ImplTrait(Vec<GenericBound>),
 }
 
-// `Type` is used a lot. Make sure it doesn't unintentionally get bigger.
-#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
-rustc_data_structures::static_assert_size!(Type, 72);
-
 impl Type {
     /// When comparing types for equality, it can help to ignore `&` wrapping.
     pub(crate) fn without_borrowed_ref(&self) -> &Type {
@@ -2230,33 +2206,18 @@ pub(crate) enum GenericArg {
     Infer,
 }
 
-// `GenericArg` can occur many times in a single `Path`, so make sure it
-// doesn't increase in size unexpectedly.
-#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
-rustc_data_structures::static_assert_size!(GenericArg, 80);
-
 #[derive(Clone, PartialEq, Eq, Debug, Hash)]
 pub(crate) enum GenericArgs {
     AngleBracketed { args: Box<[GenericArg]>, bindings: ThinVec<TypeBinding> },
     Parenthesized { inputs: Box<[Type]>, output: Option<Box<Type>> },
 }
 
-// `GenericArgs` is in every `PathSegment`, so its size can significantly
-// affect rustdoc's memory usage.
-#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
-rustc_data_structures::static_assert_size!(GenericArgs, 32);
-
 #[derive(Clone, PartialEq, Eq, Debug, Hash)]
 pub(crate) struct PathSegment {
     pub(crate) name: Symbol,
     pub(crate) args: GenericArgs,
 }
 
-// `PathSegment` usually occurs multiple times in every `Path`, so its size can
-// significantly affect rustdoc's memory usage.
-#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
-rustc_data_structures::static_assert_size!(PathSegment, 40);
-
 #[derive(Clone, Debug)]
 pub(crate) struct Typedef {
     pub(crate) type_: Type,
@@ -2527,3 +2488,19 @@ impl SubstParam {
         if let Self::Lifetime(lt) = self { Some(lt) } else { None }
     }
 }
+
+// Some nodes are used a lot. Make sure they don't unintentionally get bigger.
+#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
+mod size_asserts {
+    use super::*;
+    // These are in alphabetical order, which is easy to maintain.
+    rustc_data_structures::static_assert_size!(Crate, 72); // frequently moved by-value
+    rustc_data_structures::static_assert_size!(DocFragment, 32);
+    rustc_data_structures::static_assert_size!(GenericArg, 80);
+    rustc_data_structures::static_assert_size!(GenericArgs, 32);
+    rustc_data_structures::static_assert_size!(GenericParamDef, 56);
+    rustc_data_structures::static_assert_size!(Item, 56);
+    rustc_data_structures::static_assert_size!(ItemKind, 112);
+    rustc_data_structures::static_assert_size!(PathSegment, 40);
+    rustc_data_structures::static_assert_size!(Type, 72);
+}