From e80695709808db19ef7004bcfee34c08550a6c75 Mon Sep 17 00:00:00 2001 From: Shoyu Vanilla Date: Wed, 28 May 2025 11:15:33 +0900 Subject: [PATCH] feat: Render padding information when hovering on structs --- crates/hir/src/lib.rs | 53 ++++++++++ crates/ide/src/hover.rs | 1 + crates/ide/src/hover/render.rs | 76 +++++++++++--- crates/ide/src/hover/tests.rs | 128 +++++++++++++++++++++-- crates/rust-analyzer/src/config.rs | 3 + docs/book/src/configuration_generated.md | 7 ++ editors/code/package.json | 27 +++++ 7 files changed, 272 insertions(+), 23 deletions(-) diff --git a/crates/hir/src/lib.rs b/crates/hir/src/lib.rs index 3a91050d15..e8218cf861 100644 --- a/crates/hir/src/lib.rs +++ b/crates/hir/src/lib.rs @@ -5972,6 +5972,59 @@ impl Layout { } } + pub fn tail_padding(&self, field_size: &mut impl FnMut(usize) -> Option) -> Option { + match self.0.fields { + layout::FieldsShape::Primitive => None, + layout::FieldsShape::Union(_) => None, + layout::FieldsShape::Array { stride, count } => count.checked_sub(1).and_then(|tail| { + let tail_field_size = field_size(tail as usize)?; + let offset = stride.bytes() * tail; + self.0.size.bytes().checked_sub(offset)?.checked_sub(tail_field_size) + }), + layout::FieldsShape::Arbitrary { ref offsets, ref memory_index } => { + let tail = memory_index.last_index()?; + let tail_field_size = field_size(tail.0.into_raw().into_u32() as usize)?; + let offset = offsets.get(tail)?.bytes(); + self.0.size.bytes().checked_sub(offset)?.checked_sub(tail_field_size) + } + } + } + + pub fn largest_padding( + &self, + field_size: &mut impl FnMut(usize) -> Option, + ) -> Option { + match self.0.fields { + layout::FieldsShape::Primitive => None, + layout::FieldsShape::Union(_) => None, + layout::FieldsShape::Array { stride: _, count: 0 } => None, + layout::FieldsShape::Array { stride, .. } => { + let size = field_size(0)?; + stride.bytes().checked_sub(size) + } + layout::FieldsShape::Arbitrary { ref offsets, ref memory_index } => { + let mut reverse_index = vec![None; memory_index.len()]; + for (src, (mem, offset)) in memory_index.iter().zip(offsets.iter()).enumerate() { + reverse_index[*mem as usize] = Some((src, offset.bytes())); + } + if reverse_index.iter().any(|it| it.is_none()) { + stdx::never!(); + return None; + } + reverse_index + .into_iter() + .flatten() + .chain(std::iter::once((0, self.0.size.bytes()))) + .tuple_windows() + .filter_map(|((i, start), (_, end))| { + let size = field_size(i)?; + end.checked_sub(start)?.checked_sub(size) + }) + .max() + } + } + } + pub fn enum_tag_size(&self) -> Option { let tag_size = if let layout::Variants::Multiple { tag, tag_encoding, .. } = &self.0.variants { diff --git a/crates/ide/src/hover.rs b/crates/ide/src/hover.rs index 873e31b4a3..8bb1c708e2 100644 --- a/crates/ide/src/hover.rs +++ b/crates/ide/src/hover.rs @@ -58,6 +58,7 @@ pub struct MemoryLayoutHoverConfig { pub size: Option, pub offset: Option, pub alignment: Option, + pub padding: Option, pub niches: bool, } diff --git a/crates/ide/src/hover/render.rs b/crates/ide/src/hover/render.rs index ad720c8a62..c24864a18b 100644 --- a/crates/ide/src/hover/render.rs +++ b/crates/ide/src/hover/render.rs @@ -630,27 +630,57 @@ pub(super) fn definition( } }, |_| None, + |_| None, + ), + Definition::Adt(it @ Adt::Struct(strukt)) => render_memory_layout( + config.memory_layout, + || it.layout(db), + |_| None, + |layout| { + let mut field_size = + |i: usize| Some(strukt.fields(db).get(i)?.layout(db).ok()?.size()); + if strukt.repr(db).is_some_and(|it| it.inhibit_struct_field_reordering()) { + Some(("tail padding", layout.tail_padding(&mut field_size)?)) + } else { + Some(("largest padding", layout.largest_padding(&mut field_size)?)) + } + }, + |_| None, + ), + Definition::Adt(it) => render_memory_layout( + config.memory_layout, + || it.layout(db), + |_| None, + |_| None, + |_| None, ), - Definition::Adt(it) => { - render_memory_layout(config.memory_layout, || it.layout(db), |_| None, |_| None) - } Definition::Variant(it) => render_memory_layout( config.memory_layout, || it.layout(db), |_| None, + |_| None, |layout| layout.enum_tag_size(), ), - Definition::TypeAlias(it) => { - render_memory_layout(config.memory_layout, || it.ty(db).layout(db), |_| None, |_| None) - } - Definition::Local(it) => { - render_memory_layout(config.memory_layout, || it.ty(db).layout(db), |_| None, |_| None) - } + Definition::TypeAlias(it) => render_memory_layout( + config.memory_layout, + || it.ty(db).layout(db), + |_| None, + |_| None, + |_| None, + ), + Definition::Local(it) => render_memory_layout( + config.memory_layout, + || it.ty(db).layout(db), + |_| None, + |_| None, + |_| None, + ), Definition::SelfType(it) => render_memory_layout( config.memory_layout, || it.self_ty(db).layout(db), |_| None, |_| None, + |_| None, ), _ => None, }; @@ -1055,9 +1085,13 @@ fn closure_ty( if let Some(trait_) = c.fn_trait(sema.db).get_id(sema.db, original.krate(sema.db).into()) { push_new_def(hir::Trait::from(trait_).into()) } - if let Some(layout) = - render_memory_layout(config.memory_layout, || original.layout(sema.db), |_| None, |_| None) - { + if let Some(layout) = render_memory_layout( + config.memory_layout, + || original.layout(sema.db), + |_| None, + |_| None, + |_| None, + ) { format_to!(markup, "\n___\n{layout}"); } format_to!(markup, "{adjusted}\n\n## Captures\n{}", captures_rendered,); @@ -1142,6 +1176,7 @@ fn render_memory_layout( config: Option, layout: impl FnOnce() -> Result, offset: impl FnOnce(&Layout) -> Option, + padding: impl FnOnce(&Layout) -> Option<(&str, u64)>, tag: impl FnOnce(&Layout) -> Option, ) -> Option { let config = config?; @@ -1199,6 +1234,23 @@ fn render_memory_layout( } } + if let Some(render) = config.padding { + if let Some((padding_name, padding)) = padding(&layout) { + format_to!(label, "{padding_name} = "); + match render { + MemoryLayoutHoverRenderKind::Decimal => format_to!(label, "{padding}"), + MemoryLayoutHoverRenderKind::Hexadecimal => format_to!(label, "{padding:#X}"), + MemoryLayoutHoverRenderKind::Both if padding >= 10 => { + format_to!(label, "{padding} ({padding:#X})") + } + MemoryLayoutHoverRenderKind::Both => { + format_to!(label, "{padding}") + } + } + format_to!(label, ", "); + } + } + if config.niches { if let Some(niches) = layout.niches() { if niches > 1024 { diff --git a/crates/ide/src/hover/tests.rs b/crates/ide/src/hover/tests.rs index 06ca24c3ec..a281a49152 100644 --- a/crates/ide/src/hover/tests.rs +++ b/crates/ide/src/hover/tests.rs @@ -12,6 +12,7 @@ const HOVER_BASE_CONFIG: HoverConfig = HoverConfig { size: Some(MemoryLayoutHoverRenderKind::Both), offset: Some(MemoryLayoutHoverRenderKind::Both), alignment: Some(MemoryLayoutHoverRenderKind::Both), + padding: Some(MemoryLayoutHoverRenderKind::Both), niches: true, }), documentation: true, @@ -933,7 +934,7 @@ struct Foo$0(pub u32) where u32: Copy; --- - size = 4, align = 4, no Drop + size = 4, align = 4, largest padding = 0, no Drop "#]], ); } @@ -959,7 +960,7 @@ struct Foo$0 { field: u32 } --- - size = 4, align = 4, no Drop + size = 4, align = 4, largest padding = 0, no Drop "#]], ); check( @@ -984,7 +985,7 @@ struct Foo$0 where u32: Copy { field: u32 } --- - size = 4, align = 4, no Drop + size = 4, align = 4, largest padding = 0, no Drop "#]], ); } @@ -1013,7 +1014,7 @@ fn hover_record_struct_limit() { --- - size = 12 (0xC), align = 4, no Drop + size = 12 (0xC), align = 4, largest padding = 0, no Drop "#]], ); check_hover_fields_limit( @@ -1036,7 +1037,7 @@ fn hover_record_struct_limit() { --- - size = 4, align = 4, no Drop + size = 4, align = 4, largest padding = 0, no Drop "#]], ); check_hover_fields_limit( @@ -1062,7 +1063,7 @@ fn hover_record_struct_limit() { --- - size = 16 (0x10), align = 4, no Drop + size = 16 (0x10), align = 4, largest padding = 0, no Drop "#]], ); check_hover_fields_limit( @@ -1083,7 +1084,7 @@ fn hover_record_struct_limit() { --- - size = 12 (0xC), align = 4, no Drop + size = 12 (0xC), align = 4, largest padding = 0, no Drop "#]], ); check_hover_fields_limit( @@ -1104,7 +1105,7 @@ fn hover_record_struct_limit() { --- - size = 12 (0xC), align = 4, no Drop + size = 12 (0xC), align = 4, largest padding = 0, no Drop "#]], ); @@ -3114,7 +3115,7 @@ struct S$0(core::marker::PhantomData); --- - size = 0, align = 1, no Drop + size = 0, align = 1, largest padding = 0, no Drop "#]], ); } @@ -3147,6 +3148,111 @@ fn test_hover_layout_of_enum() { ); } +#[test] +fn test_hover_layout_padding_info() { + check( + r#"struct $0Foo { + x: bool, + y: i64, + z: u32, + }"#, + expect![[r#" + *Foo* + + ```rust + ra_test_fixture + ``` + + ```rust + struct Foo { + x: bool, + y: i64, + z: u32, + } + ``` + + --- + + size = 16 (0x10), align = 8, largest padding = 3, niches = 254, no Drop + "#]], + ); + + check( + r#"#[repr(align(32))] + struct $0Foo { + x: bool, + y: i64, + z: u32, + }"#, + expect![[r#" + *Foo* + + ```rust + ra_test_fixture + ``` + + ```rust + struct Foo { + x: bool, + y: i64, + z: u32, + } + ``` + + --- + + size = 32 (0x20), align = 32 (0x20), largest padding = 19 (0x13), niches = 254, no Drop + "#]], + ); + + check( + r#"#[repr(C)] + struct $0Foo { + x: bool, + y: i64, + z: u32, + }"#, + expect![[r#" + *Foo* + + ```rust + ra_test_fixture + ``` + + ```rust + struct Foo { + x: bool, + y: i64, + z: u32, + } + ``` + + --- + + size = 24 (0x18), align = 8, tail padding = 4, niches = 254, no Drop + "#]], + ); + + check( + r#"struct $0Foo(i16, u128, u64)"#, + expect![[r#" + *Foo* + + ```rust + ra_test_fixture + ``` + + ```rust + struct Foo(i16, u128, u64) + ``` + + --- + + size = 32 (0x20), align = 8, largest padding = 6, no Drop + "#]], + ); +} + #[test] fn test_hover_no_memory_layout() { check_hover_no_memory_layout( @@ -9198,7 +9304,7 @@ struct Pedro$0<'a> { --- - size = 16 (0x10), align = 8, niches = 1, no Drop + size = 16 (0x10), align = 8, largest padding = 0, niches = 1, no Drop "#]], ) } @@ -10559,7 +10665,7 @@ struct DropField$0 { --- - size = 4, align = 4, needs Drop + size = 4, align = 4, largest padding = 0, needs Drop "#]], ); check( diff --git a/crates/rust-analyzer/src/config.rs b/crates/rust-analyzer/src/config.rs index f7158235ca..d1ca8c1a91 100644 --- a/crates/rust-analyzer/src/config.rs +++ b/crates/rust-analyzer/src/config.rs @@ -149,6 +149,8 @@ config_data! { hover_memoryLayout_niches: Option = Some(false), /// How to render the offset information in a memory layout hover. hover_memoryLayout_offset: Option = Some(MemoryLayoutHoverRenderKindDef::Hexadecimal), + /// How to render the padding information in a memory layout hover. + hover_memoryLayout_padding: Option = None, /// How to render the size information in a memory layout hover. hover_memoryLayout_size: Option = Some(MemoryLayoutHoverRenderKindDef::Both), @@ -1635,6 +1637,7 @@ impl Config { size: self.hover_memoryLayout_size().map(mem_kind), offset: self.hover_memoryLayout_offset().map(mem_kind), alignment: self.hover_memoryLayout_alignment().map(mem_kind), + padding: self.hover_memoryLayout_padding().map(mem_kind), niches: self.hover_memoryLayout_niches().unwrap_or_default(), }), documentation: self.hover_documentation_enable().to_owned(), diff --git a/docs/book/src/configuration_generated.md b/docs/book/src/configuration_generated.md index de1d0ea4a3..0e07dadfb7 100644 --- a/docs/book/src/configuration_generated.md +++ b/docs/book/src/configuration_generated.md @@ -763,6 +763,13 @@ Default: `"hexadecimal"` How to render the offset information in a memory layout hover. +## rust-analyzer.hover.memoryLayout.padding {#hover.memoryLayout.padding} + +Default: `null` + +How to render the padding information in a memory layout hover. + + ## rust-analyzer.hover.memoryLayout.size {#hover.memoryLayout.size} Default: `"both"` diff --git a/editors/code/package.json b/editors/code/package.json index 88a90aad8c..c8c36cd85c 100644 --- a/editors/code/package.json +++ b/editors/code/package.json @@ -1779,6 +1779,33 @@ } } }, + { + "title": "hover", + "properties": { + "rust-analyzer.hover.memoryLayout.padding": { + "markdownDescription": "How to render the padding information in a memory layout hover.", + "default": null, + "anyOf": [ + { + "type": "null" + }, + { + "type": "string", + "enum": [ + "both", + "decimal", + "hexadecimal" + ], + "enumDescriptions": [ + "Render as 12 (0xC)", + "Render as 12", + "Render as 0xC" + ] + } + ] + } + } + }, { "title": "hover", "properties": {