Remove most manual LayoutData creations and move them to rustc_abi

...either as:
- methods on LayoutCalculator, for faillible operations;
- constructors on LayoutData, for infaillible ones.

Author: moulins

crates/hir-ty/src/layout.rs

@@ -15,7 +15,7 @@ use hir_def::{
 use la_arena::{Idx, RawIdx};
 use rustc_abi::AddressSpace;
 use rustc_hashes::Hash64;
-use rustc_index::{IndexSlice, IndexVec};
+use rustc_index::IndexVec;
 
 use triomphe::Arc;
 
@@ -190,7 +190,8 @@ pub fn layout_of_ty_query(
     let dl = &*target;
     let cx = LayoutCx::new(dl);
     let ty = normalize(db, trait_env.clone(), ty);
-    let result = match ty.kind(Interner) {
+    let kind = ty.kind(Interner);
+    let result = match kind {
         TyKind::Adt(AdtId(def), subst) => {
             if let hir_def::AdtId::StructId(s) = def {
                 let data = db.struct_data(*s);
@@ -216,7 +217,7 @@ pub fn layout_of_ty_query(
                     valid_range: WrappingRange { start: 0, end: 0x10FFFF },
                 },
             ),
-            chalk_ir::Scalar::Int(i) => scalar(
+            chalk_ir::Scalar::Int(i) => Layout::scalar(dl, scalar_unit(
                 dl,
                 Primitive::Int(
                     match i {
@@ -229,8 +230,8 @@ pub fn layout_of_ty_query(
                     },
                     true,
                 ),
-            ),
-            chalk_ir::Scalar::Uint(i) => scalar(
+            )),
+            chalk_ir::Scalar::Uint(i) => Layout::scalar(dl, scalar_unit(
                 dl,
                 Primitive::Int(
                     match i {
@@ -243,16 +244,16 @@ pub fn layout_of_ty_query(
                     },
                     false,
                 ),
-            ),
-            chalk_ir::Scalar::Float(f) => scalar(
+            )),
+            chalk_ir::Scalar::Float(f) => Layout::scalar(dl, scalar_unit(
                 dl,
                 Primitive::Float(match f {
                     FloatTy::F16 => Float::F16,
                     FloatTy::F32 => Float::F32,
                     FloatTy::F64 => Float::F64,
                     FloatTy::F128 => Float::F128,
                 }),
-            ),
+            )),
         },
         TyKind::Tuple(len, tys) => {
             let kind = if *len == 0 { StructKind::AlwaysSized } else { StructKind::MaybeUnsized };
@@ -268,56 +269,16 @@ pub fn layout_of_ty_query(
         TyKind::Array(element, count) => {
             let count = try_const_usize(db, count).ok_or(LayoutError::HasErrorConst)? as u64;
             let element = db.layout_of_ty(element.clone(), trait_env)?;
-            let size = element
-                .size
-                .checked_mul(count, dl)
-                .ok_or(LayoutError::BadCalc(LayoutCalculatorError::SizeOverflow))?;
-
-            let backend_repr = BackendRepr::Memory { sized: true };
-
-            let largest_niche = if count != 0 { element.largest_niche } else { None };
-            let uninhabited = if count != 0 { element.uninhabited } else { false };
-
-            Layout {
-                variants: Variants::Single { index: struct_variant_idx() },
-                fields: FieldsShape::Array { stride: element.size, count },
-                backend_repr,
-                largest_niche,
-                uninhabited,
-                align: element.align,
-                size,
-                max_repr_align: None,
-                unadjusted_abi_align: element.align.abi,
-                randomization_seed: Hash64::ZERO,
-            }
+            cx.calc.array_like::<_, _, ()>(&element, Some(count))?
         }
         TyKind::Slice(element) => {
             let element = db.layout_of_ty(element.clone(), trait_env)?;
-            Layout {
-                variants: Variants::Single { index: struct_variant_idx() },
-                fields: FieldsShape::Array { stride: element.size, count: 0 },
-                backend_repr: BackendRepr::Memory { sized: false },
-                largest_niche: None,
-                uninhabited: false,
-                align: element.align,
-                size: Size::ZERO,
-                max_repr_align: None,
-                unadjusted_abi_align: element.align.abi,
-                randomization_seed: Hash64::ZERO,
-            }
+            cx.calc.array_like::<_, _, ()>(&element, None)?
+        }
+        TyKind::Str => {
+            let element = scalar_unit(dl, Primitive::Int(Integer::I8, false));
+            cx.calc.array_like::<_, _, ()>(&Layout::scalar(dl, element), None)?
         }
-        TyKind::Str => Layout {
-            variants: Variants::Single { index: struct_variant_idx() },
-            fields: FieldsShape::Array { stride: Size::from_bytes(1), count: 0 },
-            backend_repr: BackendRepr::Memory { sized: false },
-            largest_niche: None,
-            uninhabited: false,
-            align: dl.i8_align,
-            size: Size::ZERO,
-            max_repr_align: None,
-            unadjusted_abi_align: dl.i8_align.abi,
-            randomization_seed: Hash64::ZERO,
-        },
         // Potentially-wide pointers.
         TyKind::Ref(_, _, pointee) | TyKind::Raw(_, pointee) => {
             let mut data_ptr = scalar_unit(dl, Primitive::Pointer(AddressSpace::DATA));
@@ -355,17 +316,12 @@ pub fn layout_of_ty_query(
             };
 
             // Effectively a (ptr, meta) tuple.
-            cx.calc.scalar_pair(data_ptr, metadata)
+            LayoutData::scalar_pair(dl, data_ptr, metadata)
         }
-        TyKind::FnDef(_, _) => layout_of_unit(&cx)?,
-        TyKind::Never => cx.calc.layout_of_never_type(),
-        TyKind::Dyn(_) | TyKind::Foreign(_) => {
-            let mut unit = layout_of_unit(&cx)?;
-            match &mut unit.backend_repr {
-                BackendRepr::Memory { sized } => *sized = false,
-                _ => return Err(LayoutError::Unknown),
-            }
-            unit
+        TyKind::Never => LayoutData::never_type(dl),
+        TyKind::FnDef(..) | TyKind::Dyn(_) | TyKind::Foreign(_) => {
+            let sized = matches!(kind, TyKind::FnDef(..));
+            LayoutData::unit(dl, sized)
         }
         TyKind::Function(_) => {
             let mut ptr = scalar_unit(dl, Primitive::Pointer(dl.instruction_address_space));
@@ -434,16 +390,6 @@ pub fn layout_of_ty_recover(
     Err(LayoutError::RecursiveTypeWithoutIndirection)
 }
 
-fn layout_of_unit(cx: &LayoutCx<'_>) -> Result<Layout, LayoutError> {
-    cx.calc
-        .univariant::<RustcFieldIdx, RustcEnumVariantIdx, &&Layout>(
-            IndexSlice::empty(),
-            &ReprOptions::default(),
-            StructKind::AlwaysSized,
-        )
-        .map_err(Into::into)
-}
-
 fn struct_tail_erasing_lifetimes(db: &dyn HirDatabase, pointee: Ty) -> Ty {
     match pointee.kind(Interner) {
         TyKind::Adt(AdtId(hir_def::AdtId::StructId(i)), subst) => {
@@ -474,9 +420,5 @@ fn scalar_unit(dl: &TargetDataLayout, value: Primitive) -> Scalar {
     Scalar::Initialized { value, valid_range: WrappingRange::full(value.size(dl)) }
 }
 
-fn scalar(dl: &TargetDataLayout, value: Primitive) -> Layout {
-    Layout::scalar(dl, scalar_unit(dl, value))
-}
-
 #[cfg(test)]
 mod tests;