compiler: reorganize rustc_abi to be more internally uniform

General housekeeping:
- Use less reexports from its rustc_target era
- Unify some imports as a result
- Split the Reg(ister) types into their own files

Generally moving stuff around because it makes the crate more consistent.

Author: workingjubilee

compiler/rustc_abi/src/callconv.rs

@@ -1,73 +1,10 @@
-mod abi {
-    pub(crate) use crate::Primitive::*;
-    pub(crate) use crate::Variants;
-}
-
-#[cfg(feature = "nightly")]
-use rustc_macros::HashStable_Generic;
-
-use crate::{Align, HasDataLayout, Size};
 #[cfg(feature = "nightly")]
 use crate::{BackendRepr, FieldsShape, TyAbiInterface, TyAndLayout};
+use crate::{Primitive, Size, Variants};
 
-#[cfg_attr(feature = "nightly", derive(HashStable_Generic))]
-#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
-pub enum RegKind {
-    Integer,
-    Float,
-    Vector,
-}
-
-#[cfg_attr(feature = "nightly", derive(HashStable_Generic))]
-#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
-pub struct Reg {
-    pub kind: RegKind,
-    pub size: Size,
-}
-
-macro_rules! reg_ctor {
-    ($name:ident, $kind:ident, $bits:expr) => {
-        pub fn $name() -> Reg {
-            Reg { kind: RegKind::$kind, size: Size::from_bits($bits) }
-        }
-    };
-}
-
-impl Reg {
-    reg_ctor!(i8, Integer, 8);
-    reg_ctor!(i16, Integer, 16);
-    reg_ctor!(i32, Integer, 32);
-    reg_ctor!(i64, Integer, 64);
-    reg_ctor!(i128, Integer, 128);
-
-    reg_ctor!(f32, Float, 32);
-    reg_ctor!(f64, Float, 64);
-}
+mod reg;
 
-impl Reg {
-    pub fn align<C: HasDataLayout>(&self, cx: &C) -> Align {
-        let dl = cx.data_layout();
-        match self.kind {
-            RegKind::Integer => match self.size.bits() {
-                1 => dl.i1_align.abi,
-                2..=8 => dl.i8_align.abi,
-                9..=16 => dl.i16_align.abi,
-                17..=32 => dl.i32_align.abi,
-                33..=64 => dl.i64_align.abi,
-                65..=128 => dl.i128_align.abi,
-                _ => panic!("unsupported integer: {self:?}"),
-            },
-            RegKind::Float => match self.size.bits() {
-                16 => dl.f16_align.abi,
-                32 => dl.f32_align.abi,
-                64 => dl.f64_align.abi,
-                128 => dl.f128_align.abi,
-                _ => panic!("unsupported float: {self:?}"),
-            },
-            RegKind::Vector => dl.vector_align(self.size).abi,
-        }
-    }
-}
+pub use reg::{Reg, RegKind};
 
 /// Return value from the `homogeneous_aggregate` test function.
 #[derive(Copy, Clone, Debug)]
@@ -134,8 +71,8 @@ impl<'a, Ty> TyAndLayout<'a, Ty> {
             // The primitive for this algorithm.
             BackendRepr::Scalar(scalar) => {
                 let kind = match scalar.primitive() {
-                    abi::Int(..) | abi::Pointer(_) => RegKind::Integer,
-                    abi::Float(_) => RegKind::Float,
+                    Primitive::Int(..) | Primitive::Pointer(_) => RegKind::Integer,
+                    Primitive::Float(_) => RegKind::Float,
                 };
                 Ok(HomogeneousAggregate::Homogeneous(Reg { kind, size: self.size }))
             }
@@ -206,8 +143,8 @@ impl<'a, Ty> TyAndLayout<'a, Ty> {
                 let (mut result, mut total) = from_fields_at(*self, Size::ZERO)?;
 
                 match &self.variants {
-                    abi::Variants::Single { .. } | abi::Variants::Empty => {}
-                    abi::Variants::Multiple { variants, .. } => {
+                    Variants::Single { .. } | Variants::Empty => {}
+                    Variants::Multiple { variants, .. } => {
                         // Treat enum variants like union members.
                         // HACK(eddyb) pretend the `enum` field (discriminant)
                         // is at the start of every variant (otherwise the gap

compiler/rustc_abi/src/callconv/reg.rs

@@ -0,0 +1,63 @@
+#[cfg(feature = "nightly")]
+use rustc_macros::HashStable_Generic;
+
+use crate::{Align, HasDataLayout, Size};
+
+#[cfg_attr(feature = "nightly", derive(HashStable_Generic))]
+#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
+pub enum RegKind {
+    Integer,
+    Float,
+    Vector,
+}
+
+#[cfg_attr(feature = "nightly", derive(HashStable_Generic))]
+#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
+pub struct Reg {
+    pub kind: RegKind,
+    pub size: Size,
+}
+
+macro_rules! reg_ctor {
+    ($name:ident, $kind:ident, $bits:expr) => {
+        pub fn $name() -> Reg {
+            Reg { kind: RegKind::$kind, size: Size::from_bits($bits) }
+        }
+    };
+}
+
+impl Reg {
+    reg_ctor!(i8, Integer, 8);
+    reg_ctor!(i16, Integer, 16);
+    reg_ctor!(i32, Integer, 32);
+    reg_ctor!(i64, Integer, 64);
+    reg_ctor!(i128, Integer, 128);
+
+    reg_ctor!(f32, Float, 32);
+    reg_ctor!(f64, Float, 64);
+}
+
+impl Reg {
+    pub fn align<C: HasDataLayout>(&self, cx: &C) -> Align {
+        let dl = cx.data_layout();
+        match self.kind {
+            RegKind::Integer => match self.size.bits() {
+                1 => dl.i1_align.abi,
+                2..=8 => dl.i8_align.abi,
+                9..=16 => dl.i16_align.abi,
+                17..=32 => dl.i32_align.abi,
+                33..=64 => dl.i64_align.abi,
+                65..=128 => dl.i128_align.abi,
+                _ => panic!("unsupported integer: {self:?}"),
+            },
+            RegKind::Float => match self.size.bits() {
+                16 => dl.f16_align.abi,
+                32 => dl.f32_align.abi,
+                64 => dl.f64_align.abi,
+                128 => dl.f128_align.abi,
+                _ => panic!("unsupported float: {self:?}"),
+            },
+            RegKind::Vector => dl.vector_align(self.size).abi,
+        }
+    }
+}

compiler/rustc_abi/src/extern_abi/mod.rs compiler/rustc_abi/src/extern_abi.rs

@@ -1,13 +1,15 @@
 use std::fmt;
 use std::ops::Deref;
 
-use Float::*;
-use Primitive::*;
 use rustc_data_structures::intern::Interned;
 use rustc_macros::HashStable_Generic;
 
+use crate::{
+    AbiAndPrefAlign, Align, BackendRepr, FieldsShape, Float, HasDataLayout, LayoutData, Niche,
+    PointeeInfo, Primitive, Scalar, Size, TargetDataLayout, Variants,
+};
+
 // Explicitly import `Float` to avoid ambiguity with `Primitive::Float`.
-use crate::{Float, *};
 
 rustc_index::newtype_index! {
     /// The *source-order* index of a field in a variant.
@@ -197,7 +199,9 @@ impl<'a, Ty> TyAndLayout<'a, Ty> {
         C: HasDataLayout,
     {
         match self.backend_repr {
-            BackendRepr::Scalar(scalar) => matches!(scalar.primitive(), Float(F32 | F64)),
+            BackendRepr::Scalar(scalar) => {
+                matches!(scalar.primitive(), Primitive::Float(Float::F32 | Float::F64))
+            }
             BackendRepr::Memory { .. } => {
                 if self.fields.count() == 1 && self.fields.offset(0).bytes() == 0 {
                     self.field(cx, 0).is_single_fp_element(cx)