Auto merge of #14845 - HKalbasi:layout, r=HKalbasi

Add layout info for enum variant and locals The size of enum variant is what rustdoc shows (https://github.com/rust-lang/rust/pull/86263). I also added layout info for locals since it helps finding size of unnameable types like closures inside other structs or impl traits.
2024-11-25 00:03:43 +00:00 · 2023-05-18 19:56:16 +00:00 · 2023-05-18 19:56:16 +00:00 · e110696118
commit e110696118
parent 54129fa113 cae9660a1d
3 changed files with 184 additions and 95 deletions
--- a/crates/hir/src/lib.rs
+++ b/crates/hir/src/lib.rs
@ -45,7 +45,7 @@ use hir_def::{
    hir::{BindingAnnotation, BindingId, ExprOrPatId, LabelId, Pat},
    item_tree::ItemTreeNode,
    lang_item::LangItemTarget,
-    layout::ReprOptions,
+    layout::{self, ReprOptions},
    macro_id_to_def_id,
    nameres::{self, diagnostics::DefDiagnostic, ModuleOrigin},
    per_ns::PerNs,
@ -62,7 +62,7 @@ use hir_ty::{
    consteval::{try_const_usize, unknown_const_as_generic, ConstEvalError, ConstExt},
    diagnostics::BodyValidationDiagnostic,
    display::HexifiedConst,
-    layout::{layout_of_ty, Layout, LayoutError},
+    layout::{layout_of_ty, Layout, LayoutError, RustcEnumVariantIdx, TagEncoding},
    method_resolution::{self, TyFingerprint},
    mir::{self, interpret_mir},
    primitive::UintTy,
@ -1089,7 +1089,7 @@ impl Enum {
        Type::new_for_crate(
            self.id.lookup(db.upcast()).container.krate(),
            TyBuilder::builtin(match db.enum_data(self.id).variant_body_type() {
-                hir_def::layout::IntegerType::Pointer(sign) => match sign {
+                layout::IntegerType::Pointer(sign) => match sign {
                    true => hir_def::builtin_type::BuiltinType::Int(
                        hir_def::builtin_type::BuiltinInt::Isize,
                    ),
@ -1097,20 +1097,20 @@ impl Enum {
                        hir_def::builtin_type::BuiltinUint::Usize,
                    ),
                },
-                hir_def::layout::IntegerType::Fixed(i, sign) => match sign {
+                layout::IntegerType::Fixed(i, sign) => match sign {
                    true => hir_def::builtin_type::BuiltinType::Int(match i {
-                        hir_def::layout::Integer::I8 => hir_def::builtin_type::BuiltinInt::I8,
-                        hir_def::layout::Integer::I16 => hir_def::builtin_type::BuiltinInt::I16,
-                        hir_def::layout::Integer::I32 => hir_def::builtin_type::BuiltinInt::I32,
-                        hir_def::layout::Integer::I64 => hir_def::builtin_type::BuiltinInt::I64,
-                        hir_def::layout::Integer::I128 => hir_def::builtin_type::BuiltinInt::I128,
+                        layout::Integer::I8 => hir_def::builtin_type::BuiltinInt::I8,
+                        layout::Integer::I16 => hir_def::builtin_type::BuiltinInt::I16,
+                        layout::Integer::I32 => hir_def::builtin_type::BuiltinInt::I32,
+                        layout::Integer::I64 => hir_def::builtin_type::BuiltinInt::I64,
+                        layout::Integer::I128 => hir_def::builtin_type::BuiltinInt::I128,
                    }),
                    false => hir_def::builtin_type::BuiltinType::Uint(match i {
-                        hir_def::layout::Integer::I8 => hir_def::builtin_type::BuiltinUint::U8,
-                        hir_def::layout::Integer::I16 => hir_def::builtin_type::BuiltinUint::U16,
-                        hir_def::layout::Integer::I32 => hir_def::builtin_type::BuiltinUint::U32,
-                        hir_def::layout::Integer::I64 => hir_def::builtin_type::BuiltinUint::U64,
-                        hir_def::layout::Integer::I128 => hir_def::builtin_type::BuiltinUint::U128,
+                        layout::Integer::I8 => hir_def::builtin_type::BuiltinUint::U8,
+                        layout::Integer::I16 => hir_def::builtin_type::BuiltinUint::U16,
+                        layout::Integer::I32 => hir_def::builtin_type::BuiltinUint::U32,
+                        layout::Integer::I64 => hir_def::builtin_type::BuiltinUint::U64,
+                        layout::Integer::I128 => hir_def::builtin_type::BuiltinUint::U128,
                    }),
                },
            }),
@ -1177,6 +1177,28 @@ impl Variant {
    pub fn eval(self, db: &dyn HirDatabase) -> Result<i128, ConstEvalError> {
        db.const_eval_discriminant(self.into())
    }
+
+    /// Return layout of the variant and tag size of the parent enum.
+    pub fn layout(&self, db: &dyn HirDatabase) -> Result<(Layout, usize), LayoutError> {
+        let parent_enum = self.parent_enum(db);
+        let parent_layout = Adt::from(parent_enum).layout(db)?;
+        if let layout::Variants::Multiple { variants, tag, tag_encoding, tag_field: _ } =
+            parent_layout.variants
+        {
+            let tag_size = match tag_encoding {
+                TagEncoding::Direct => {
+                    let target_data_layout = db
+                        .target_data_layout(parent_enum.module(db).krate().id)
+                        .ok_or(LayoutError::TargetLayoutNotAvailable)?;
+                    tag.size(&*target_data_layout).bytes_usize()
+                }
+                TagEncoding::Niche { .. } => 0,
+            };
+            Ok((variants[RustcEnumVariantIdx(self.id)].clone(), tag_size))
+        } else {
+            Ok((parent_layout, 0))
+        }
+    }
 }

 /// Variants inherit visibility from the parent enum.
--- a/crates/ide/src/hover/render.rs
+++ b/crates/ide/src/hover/render.rs
@ -417,15 +417,25 @@ pub(super) fn definition(
            let layout = it.layout(db).ok()?;
            Some(format!("size = {}, align = {}", layout.size.bytes(), layout.align.abi.bytes()))
        }),
-        Definition::Variant(it) => label_value_and_docs(db, it, |&it| {
-            if !it.parent_enum(db).is_data_carrying(db) {
+        Definition::Variant(it) => label_value_and_layout_info_and_docs(db, it, config, |&it| {
+            let layout = (|| {
+                let (layout, tag_size) = it.layout(db).ok()?;
+                let size = layout.size.bytes_usize() - tag_size;
+                if size == 0 {
+                    // There is no value in showing layout info for fieldless variants
+                    return None;
+                }
+                Some(format!("size = {}", layout.size.bytes()))
+            })();
+            let value = if !it.parent_enum(db).is_data_carrying(db) {
                match it.eval(db) {
                    Ok(x) => Some(if x >= 10 { format!("{x} ({x:#X})") } else { format!("{x}") }),
                    Err(_) => it.value(db).map(|x| format!("{x:?}")),
                }
            } else {
                None
-            }
+            };
+            (value, layout)
        }),
        Definition::Const(it) => label_value_and_docs(db, it, |it| {
            let body = it.render_eval(db);
@ -460,7 +470,7 @@ pub(super) fn definition(
                .and_then(|fd| builtin(fd, it))
                .or_else(|| Some(Markup::fenced_block(&it.name())))
        }
-        Definition::Local(it) => return local(db, it),
+        Definition::Local(it) => return local(db, it, config),
        Definition::SelfType(impl_def) => {
            impl_def.self_ty(db).as_adt().map(|adt| label_and_docs(db, adt))?
        }
@ -637,6 +647,32 @@ where
    (label, docs)
 }

+fn label_value_and_layout_info_and_docs<D, E, V, L>(
+    db: &RootDatabase,
+    def: D,
+    config: &HoverConfig,
+    value_extractor: E,
+) -> (String, Option<hir::Documentation>)
+where
+    D: HasAttrs + HirDisplay,
+    E: Fn(&D) -> (Option<V>, Option<L>),
+    V: Display,
+    L: Display,
+{
+    let (value, layout) = value_extractor(&def);
+    let label = if let Some(value) = value {
+        format!("{} = {value}", def.display(db))
+    } else {
+        def.display(db).to_string()
+    };
+    let label = match layout {
+        Some(layout) if config.memory_layout => format!("{} // {layout}", label),
+        _ => label,
+    };
+    let docs = def.attrs(db).docs();
+    (label, docs)
+}
+
 fn label_value_and_docs<D, E, V>(
    db: &RootDatabase,
    def: D,
@ -696,11 +732,11 @@ fn find_std_module(famous_defs: &FamousDefs<'_, '_>, name: &str) -> Option<hir::
        .find(|module| module.name(db).map_or(false, |module| module.to_string() == name))
 }

-fn local(db: &RootDatabase, it: hir::Local) -> Option<Markup> {
+fn local(db: &RootDatabase, it: hir::Local, config: &HoverConfig) -> Option<Markup> {
    let ty = it.ty(db);
    let ty = ty.display_truncated(db, None);
    let is_mut = if it.is_mut(db) { "mut " } else { "" };
-    let desc = match it.primary_source(db).into_ident_pat() {
+    let mut desc = match it.primary_source(db).into_ident_pat() {
        Some(ident) => {
            let name = it.name(db);
            let let_kw = if ident
@ -716,6 +752,16 @@ fn local(db: &RootDatabase, it: hir::Local) -> Option<Markup> {
        }
        None => format!("{is_mut}self: {ty}"),
    };
+    if config.memory_layout {
+        if let Ok(layout) = it.ty(db).layout(db) {
+            format_to!(
+                desc,
+                " // size = {}, align = {}",
+                layout.size.bytes(),
+                layout.align.abi.bytes()
+            );
+        }
+    }
    markup(None, desc, None)
 }

--- a/crates/ide/src/hover/tests.rs
+++ b/crates/ide/src/hover/tests.rs
@ -150,7 +150,7 @@ fn foo() {
            *local*

            ```rust
-            let local: i32
+            let local: i32 // size = 4, align = 4
            ```
        "#]],
    );
@ -399,7 +399,7 @@ fn main() {
            *iter*

            ```rust
-                let mut iter: Iter<Scan<OtherStruct<OtherStruct<i32>>, impl Fn(&mut u32, &u32, &mut u32) -> Option<u32>, u32>>
+            let mut iter: Iter<Scan<OtherStruct<OtherStruct<i32>>, impl Fn(&mut u32, &u32, &mut u32) -> Option<u32>, u32>> // size = 8, align = 4
            ```
        "#]],
    );
@ -781,7 +781,7 @@ fn main() {
            *zz*

            ```rust
-                let zz: Test<i32>
+            let zz: Test<i32> // size = 8, align = 4
            ```
        "#]],
    );
@ -832,7 +832,7 @@ fn main() { let b$0ar = Some(12); }
            *bar*

            ```rust
-                let bar: Option<i32>
+            let bar: Option<i32> // size = 4, align = 4
            ```
        "#]],
    );
@ -901,7 +901,7 @@ fn hover_for_local_variable() {
            *foo*

            ```rust
-                foo: i32
+            foo: i32 // size = 4, align = 4
            ```
        "#]],
    )
@ -915,7 +915,7 @@ fn hover_for_local_variable_pat() {
            *foo*

            ```rust
-                foo: i32
+            foo: i32 // size = 4, align = 4
            ```
        "#]],
    )
@ -929,7 +929,7 @@ fn hover_local_var_edge() {
            *foo*

            ```rust
-                foo: i32
+            foo: i32 // size = 4, align = 4
            ```
        "#]],
    )
@ -943,7 +943,7 @@ fn hover_for_param_edge() {
            *foo*

            ```rust
-                foo: i32
+            foo: i32 // size = 4, align = 4
            ```
        "#]],
    )
@ -987,7 +987,7 @@ fn main() { let foo_$0test = Thing::new(); }
            *foo_test*

            ```rust
-                let foo_test: Thing
+            let foo_test: Thing // size = 4, align = 4
            ```
        "#]],
    )
@ -1147,7 +1147,7 @@ fn y() {
            *x*

            ```rust
-                let x: i32
+            let x: i32 // size = 4, align = 4
            ```
        "#]],
    )
@ -1277,7 +1277,7 @@ fn foo(bar:u32) { let a = id!(ba$0r); }
            *bar*

            ```rust
-                bar: u32
+            bar: u32 // size = 4, align = 4
            ```
        "#]],
    );
@ -1295,7 +1295,7 @@ fn foo(bar:u32) { let a = id!(ba$0r); }
            *bar*

            ```rust
-                bar: u32
+            bar: u32 // size = 4, align = 4
            ```
        "#]],
    );
@ -1841,6 +1841,27 @@ pub fn fo$0o() {}
    );
 }

+#[test]
+fn test_hover_layout_of_variant() {
+    check(
+        r#"enum Foo {
+            Va$0riant1(u8, u16),
+            Variant2(i32, u8, i64),
+        }"#,
+        expect![[r#"
+            *Variant1*
+
+            ```rust
+            test::Foo
+            ```
+
+            ```rust
+            Variant1(u8, u16) // size = 4
+            ```
+        "#]],
+    );
+}
+
 #[test]
 fn test_hover_no_memory_layout() {
    check_hover_no_memory_layout(
@ -3135,7 +3156,7 @@ fn main() {
            *f*

            ```rust
-            f: &i32
+            f: &i32 // size = 8, align = 8
            ```
            ---

@ -3185,7 +3206,7 @@ fn main() {
            *value*

            ```rust
-            let value: Const<1>
+            let value: Const<1> // size = 0, align = 1
            ```
        "#]],
    );
@ -3205,7 +3226,7 @@ fn main() {
            *value*

            ```rust
-            let value: Const<0>
+            let value: Const<0> // size = 0, align = 1
            ```
        "#]],
    );
@ -3225,7 +3246,7 @@ fn main() {
            *value*

            ```rust
-            let value: Const<-1>
+            let value: Const<-1> // size = 0, align = 1
            ```
        "#]],
    );
@ -3245,7 +3266,7 @@ fn main() {
            *value*

            ```rust
-            let value: Const<true>
+            let value: Const<true> // size = 0, align = 1
            ```
        "#]],
    );
@ -3265,7 +3286,7 @@ fn main() {
            *value*

            ```rust
-            let value: Const<'🦀'>
+            let value: Const<'🦀'> // size = 0, align = 1
            ```
        "#]],
    );
@ -3284,7 +3305,7 @@ impl Foo {
            *self*

            ```rust
-                self: &Foo
+            self: &Foo // size = 8, align = 8
            ```
        "#]],
    );
@ -3304,7 +3325,7 @@ impl Foo {
            *self*

            ```rust
-                self: Arc<Foo>
+            self: Arc<Foo> // size = 0, align = 1
            ```
        "#]],
    );
@ -4364,7 +4385,7 @@ fn main() {
            *tile4*

            ```rust
-            let tile4: [u32; 8]
+            let tile4: [u32; 8] // size = 32, align = 4
            ```
        "#]],
    );
@ -5541,7 +5562,7 @@ enum Enum {
            ```

            ```rust
-            RecordV { field: u32 }
+            RecordV { field: u32 } // size = 4
            ```
        "#]],
    );