Rollup merge of #99973 - RalfJung:layout-things, r=eddyb

Layout things

These two commits are pretty independent, but didn't seem worth doing individual PRs for:
- Always check that size is a multiple of align, even without debug assertions
- Change Layout debug printing to put `variants` last, since it often huge and not usually the part we are most interested in

Cc `@eddyb`

compiler/rustc_middle/src/ty/layout.rs

@@ -232,6 +232,10 @@ fn sanity_check_layout<'tcx>(
         assert!(layout.abi.is_uninhabited());
     }
 
+    if layout.size.bytes() % layout.align.abi.bytes() != 0 {
+        bug!("size is not a multiple of align, in the following layout:\n{layout:#?}");
+    }
+
     if cfg!(debug_assertions) {
         fn check_layout_abi<'tcx>(tcx: TyCtxt<'tcx>, layout: Layout<'tcx>) {
             match layout.abi() {

compiler/rustc_target/src/abi/mod.rs

@@ -1279,13 +1279,14 @@ impl<'a> fmt::Debug for LayoutS<'a> {
         // This is how `Layout` used to print before it become
         // `Interned<LayoutS>`. We print it like this to avoid having to update
         // expected output in a lot of tests.
+        let LayoutS { size, align, abi, fields, largest_niche, variants } = self;
         f.debug_struct("Layout")
-            .field("fields", &self.fields)
-            .field("variants", &self.variants)
-            .field("abi", &self.abi)
-            .field("largest_niche", &self.largest_niche)
-            .field("align", &self.align)
-            .field("size", &self.size)
+            .field("size", size)
+            .field("align", align)
+            .field("abi", abi)
+            .field("fields", fields)
+            .field("largest_niche", largest_niche)
+            .field("variants", variants)
             .finish()
     }
 }