Auto merge of #100944 - nnethercote:shrink-thir-Expr, r=cjgillot

Shrink `thir::Expr`

r? `@cjgillot`

compiler/rustc_middle/src/thir.rs

@@ -15,50 +15,33 @@ use rustc_hir::def_id::DefId;
 use rustc_hir::RangeEnd;
 use rustc_index::newtype_index;
 use rustc_index::vec::IndexVec;
-use rustc_middle::infer::canonical::Canonical;
 use rustc_middle::middle::region;
 use rustc_middle::mir::interpret::AllocId;
 use rustc_middle::mir::{self, BinOp, BorrowKind, FakeReadCause, Field, Mutability, UnOp};
 use rustc_middle::ty::adjustment::PointerCast;
 use rustc_middle::ty::subst::SubstsRef;
-use rustc_middle::ty::CanonicalUserTypeAnnotation;
-use rustc_middle::ty::{self, AdtDef, Ty, UpvarSubsts, UserType};
+use rustc_middle::ty::{self, AdtDef, Ty, UpvarSubsts};
+use rustc_middle::ty::{CanonicalUserType, CanonicalUserTypeAnnotation};
+use rustc_span::def_id::LocalDefId;
 use rustc_span::{Span, Symbol, DUMMY_SP};
 use rustc_target::abi::VariantIdx;
 use rustc_target::asm::InlineAsmRegOrRegClass;
-
-use rustc_span::def_id::LocalDefId;
 use std::fmt;
 use std::ops::Index;
 
 pub mod visit;
 
-newtype_index! {
-    /// An index to an [`Arm`] stored in [`Thir::arms`]
-    #[derive(HashStable)]
-    pub struct ArmId {
-        DEBUG_FORMAT = "a{}"
-    }
-}
-
-newtype_index! {
-    /// An index to an [`Expr`] stored in [`Thir::exprs`]
-    #[derive(HashStable)]
-    pub struct ExprId {
-        DEBUG_FORMAT = "e{}"
-    }
-}
-
-newtype_index! {
-    #[derive(HashStable)]
-    /// An index to a [`Stmt`] stored in [`Thir::stmts`]
-    pub struct StmtId {
-        DEBUG_FORMAT = "s{}"
-    }
-}
-
 macro_rules! thir_with_elements {
-    ($($name:ident: $id:ty => $value:ty,)*) => {
+    ($($name:ident: $id:ty => $value:ty => $format:literal,)*) => {
+        $(
+            newtype_index! {
+                #[derive(HashStable)]
+                pub struct $id {
+                    DEBUG_FORMAT = $format
+                }
+            }
+        )*
+
         /// A container for a THIR body.
         ///
         /// This can be indexed directly by any THIR index (e.g. [`ExprId`]).
@@ -91,9 +74,10 @@ macro_rules! thir_with_elements {
 }
 
 thir_with_elements! {
-    arms: ArmId => Arm<'tcx>,
-    exprs: ExprId => Expr<'tcx>,
-    stmts: StmtId => Stmt<'tcx>,
+    arms: ArmId => Arm<'tcx> => "a{}",
+    blocks: BlockId => Block => "b{}",
+    exprs: ExprId => Expr<'tcx> => "e{}",
+    stmts: StmtId => Stmt<'tcx> => "s{}",
 }
 
 #[derive(Copy, Clone, Debug, HashStable)]
@@ -121,8 +105,10 @@ pub struct Block {
     pub safety_mode: BlockSafety,
 }
 
+type UserTy<'tcx> = Option<Box<CanonicalUserType<'tcx>>>;
+
 #[derive(Clone, Debug, HashStable)]
-pub struct Adt<'tcx> {
+pub struct AdtExpr<'tcx> {
     /// The ADT we're constructing.
     pub adt_def: AdtDef<'tcx>,
     /// The variant of the ADT.
@@ -131,13 +117,30 @@ pub struct Adt<'tcx> {
 
     /// Optional user-given substs: for something like `let x =
     /// Bar::<T> { ... }`.
-    pub user_ty: Option<Canonical<'tcx, UserType<'tcx>>>,
+    pub user_ty: UserTy<'tcx>,
 
     pub fields: Box<[FieldExpr]>,
     /// The base, e.g. `Foo {x: 1, .. base}`.
     pub base: Option<FruInfo<'tcx>>,
 }
 
+#[derive(Clone, Debug, HashStable)]
+pub struct ClosureExpr<'tcx> {
+    pub closure_id: LocalDefId,
+    pub substs: UpvarSubsts<'tcx>,
+    pub upvars: Box<[ExprId]>,
+    pub movability: Option<hir::Movability>,
+    pub fake_reads: Vec<(ExprId, FakeReadCause, hir::HirId)>,
+}
+
+#[derive(Clone, Debug, HashStable)]
+pub struct InlineAsmExpr<'tcx> {
+    pub template: &'tcx [InlineAsmTemplatePiece],
+    pub operands: Box<[InlineAsmOperand<'tcx>]>,
+    pub options: InlineAsmOptions,
+    pub line_spans: &'tcx [Span],
+}
+
 #[derive(Copy, Clone, Debug, HashStable)]
 pub enum BlockSafety {
     Safe,
@@ -183,7 +186,7 @@ pub enum StmtKind<'tcx> {
         initializer: Option<ExprId>,
 
         /// `let pat: ty = <INIT> else { <ELSE> }
-        else_block: Option<Block>,
+        else_block: Option<BlockId>,
 
         /// The lint level for this `let` statement.
         lint_level: LintLevel,
@@ -307,7 +310,7 @@ pub enum ExprKind<'tcx> {
     },
     /// A block.
     Block {
-        body: Block,
+        block: BlockId,
     },
     /// An assignment: `lhs = rhs`.
     Assign {
@@ -387,27 +390,21 @@ pub enum ExprKind<'tcx> {
         fields: Box<[ExprId]>,
     },
     /// An ADT constructor, e.g. `Foo {x: 1, y: 2}`.
-    Adt(Box<Adt<'tcx>>),
+    Adt(Box<AdtExpr<'tcx>>),
     /// A type ascription on a place.
     PlaceTypeAscription {
         source: ExprId,
         /// Type that the user gave to this expression
-        user_ty: Option<Canonical<'tcx, UserType<'tcx>>>,
+        user_ty: UserTy<'tcx>,
     },
     /// A type ascription on a value, e.g. `42: i32`.
     ValueTypeAscription {
         source: ExprId,
         /// Type that the user gave to this expression
-        user_ty: Option<Canonical<'tcx, UserType<'tcx>>>,
+        user_ty: UserTy<'tcx>,
     },
     /// A closure definition.
-    Closure {
-        closure_id: LocalDefId,
-        substs: UpvarSubsts<'tcx>,
-        upvars: Box<[ExprId]>,
-        movability: Option<hir::Movability>,
-        fake_reads: Vec<(ExprId, FakeReadCause, hir::HirId)>,
-    },
+    Closure(Box<ClosureExpr<'tcx>>),
     /// A literal.
     Literal {
         lit: &'tcx hir::Lit,
@@ -416,17 +413,17 @@ pub enum ExprKind<'tcx> {
     /// For literals that don't correspond to anything in the HIR
     NonHirLiteral {
         lit: ty::ScalarInt,
-        user_ty: Option<Canonical<'tcx, UserType<'tcx>>>,
+        user_ty: UserTy<'tcx>,
     },
     /// A literal of a ZST type.
     ZstLiteral {
-        user_ty: Option<Canonical<'tcx, UserType<'tcx>>>,
+        user_ty: UserTy<'tcx>,
     },
     /// Associated constants and named constants
     NamedConst {
         def_id: DefId,
         substs: SubstsRef<'tcx>,
-        user_ty: Option<Canonical<'tcx, UserType<'tcx>>>,
+        user_ty: UserTy<'tcx>,
     },
     ConstParam {
         param: ty::ParamConst,
@@ -443,12 +440,7 @@ pub enum ExprKind<'tcx> {
         def_id: DefId,
     },
     /// Inline assembly, i.e. `asm!()`.
-    InlineAsm {
-        template: &'tcx [InlineAsmTemplatePiece],
-        operands: Box<[InlineAsmOperand<'tcx>]>,
-        options: InlineAsmOptions,
-        line_spans: &'tcx [Span],
-    },
+    InlineAsm(Box<InlineAsmExpr<'tcx>>),
     /// An expression taking a reference to a thread local.
     ThreadLocalRef(DefId),
     /// A `yield` expression.
@@ -815,7 +807,10 @@ mod size_asserts {
     use super::*;
     // These are in alphabetical order, which is easy to maintain.
     static_assert_size!(Block, 56);
-    static_assert_size!(Expr<'_>, 104);
+    static_assert_size!(Expr<'_>, 64);
+    static_assert_size!(ExprKind<'_>, 40);
     static_assert_size!(Pat<'_>, 24);
-    static_assert_size!(Stmt<'_>, 120);
+    static_assert_size!(PatKind<'_>, 112);
+    static_assert_size!(Stmt<'_>, 72);
+    static_assert_size!(StmtKind<'_>, 64);
 }

compiler/rustc_middle/src/thir/visit.rs

@@ -1,5 +1,6 @@
 use super::{
-    Arm, Block, Expr, ExprKind, Guard, InlineAsmOperand, Pat, PatKind, Stmt, StmtKind, Thir,
+    AdtExpr, Arm, Block, ClosureExpr, Expr, ExprKind, Guard, InlineAsmExpr, InlineAsmOperand, Pat,
+    PatKind, Stmt, StmtKind, Thir,
 };
 
 pub trait Visitor<'a, 'tcx: 'a>: Sized {
@@ -75,7 +76,7 @@ pub fn walk_expr<'a, 'tcx: 'a, V: Visitor<'a, 'tcx>>(visitor: &mut V, expr: &Exp
                 visitor.visit_arm(&visitor.thir()[arm]);
             }
         }
-        Block { ref body } => visitor.visit_block(body),
+        Block { block } => visitor.visit_block(&visitor.thir()[block]),
         Assign { lhs, rhs } | AssignOp { lhs, rhs, op: _ } => {
             visitor.visit_expr(&visitor.thir()[lhs]);
             visitor.visit_expr(&visitor.thir()[rhs]);
@@ -108,7 +109,7 @@ pub fn walk_expr<'a, 'tcx: 'a, V: Visitor<'a, 'tcx>>(visitor: &mut V, expr: &Exp
                 visitor.visit_expr(&visitor.thir()[field]);
             }
         }
-        Adt(box crate::thir::Adt {
+        Adt(box AdtExpr {
             ref fields,
             ref base,
             adt_def: _,
@@ -126,14 +127,20 @@ pub fn walk_expr<'a, 'tcx: 'a, V: Visitor<'a, 'tcx>>(visitor: &mut V, expr: &Exp
         PlaceTypeAscription { source, user_ty: _ } | ValueTypeAscription { source, user_ty: _ } => {
             visitor.visit_expr(&visitor.thir()[source])
         }
-        Closure { closure_id: _, substs: _, upvars: _, movability: _, fake_reads: _ } => {}
+        Closure(box ClosureExpr {
+            closure_id: _,
+            substs: _,
+            upvars: _,
+            movability: _,
+            fake_reads: _,
+        }) => {}
         Literal { lit: _, neg: _ } => {}
         NonHirLiteral { lit: _, user_ty: _ } => {}
         ZstLiteral { user_ty: _ } => {}
         NamedConst { def_id: _, substs: _, user_ty: _ } => {}
         ConstParam { param: _, def_id: _ } => {}
         StaticRef { alloc_id: _, ty: _, def_id: _ } => {}
-        InlineAsm { ref operands, template: _, options: _, line_spans: _ } => {
+        InlineAsm(box InlineAsmExpr { ref operands, template: _, options: _, line_spans: _ }) => {
             for op in &**operands {
                 use InlineAsmOperand::*;
                 match op {
@@ -174,7 +181,7 @@ pub fn walk_stmt<'a, 'tcx: 'a, V: Visitor<'a, 'tcx>>(visitor: &mut V, stmt: &Stm
             }
             visitor.visit_pat(pattern);
             if let Some(block) = else_block {
-                visitor.visit_block(block)
+                visitor.visit_block(&visitor.thir()[*block])
             }
         }
     }

compiler/rustc_mir_build/src/build/block.rs

@@ -11,7 +11,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         &mut self,
         destination: Place<'tcx>,
         block: BasicBlock,
-        ast_block: &Block,
+        ast_block: BlockId,
         source_info: SourceInfo,
     ) -> BlockAnd<()> {
         let Block {
@@ -22,7 +22,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             expr,
             targeted_by_break,
             safety_mode,
-        } = *ast_block;
+        } = self.thir[ast_block];
         let expr = expr.map(|expr| &self.thir[expr]);
         self.in_opt_scope(opt_destruction_scope.map(|de| (de, source_info)), move |this| {
             this.in_scope((region_scope, source_info), LintLevel::Inherited, move |this| {
@@ -146,7 +146,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                                                 block,
                                                 init,
                                                 initializer_span,
-                                                else_block,
+                                                *else_block,
                                                 visibility_scope,
                                                 last_remainder_scope,
                                                 remainder_span,

compiler/rustc_mir_build/src/build/expr/as_constant.rs

@@ -41,35 +41,35 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
 
                 Constant { span, user_ty: None, literal }
             }
-            ExprKind::NonHirLiteral { lit, user_ty } => {
-                let user_ty = user_ty.map(|user_ty| {
+            ExprKind::NonHirLiteral { lit, ref user_ty } => {
+                let user_ty = user_ty.as_ref().map(|box user_ty| {
                     this.canonical_user_type_annotations.push(CanonicalUserTypeAnnotation {
                         span,
-                        user_ty,
+                        user_ty: *user_ty,
                         inferred_ty: ty,
                     })
                 });
                 let literal = ConstantKind::Val(ConstValue::Scalar(Scalar::Int(lit)), ty);
 
                 Constant { span, user_ty: user_ty, literal }
             }
-            ExprKind::ZstLiteral { user_ty } => {
-                let user_ty = user_ty.map(|user_ty| {
+            ExprKind::ZstLiteral { ref user_ty } => {
+                let user_ty = user_ty.as_ref().map(|box user_ty| {
                     this.canonical_user_type_annotations.push(CanonicalUserTypeAnnotation {
                         span,
-                        user_ty,
+                        user_ty: *user_ty,
                         inferred_ty: ty,
                     })
                 });
                 let literal = ConstantKind::Val(ConstValue::ZeroSized, ty);
 
                 Constant { span, user_ty: user_ty, literal }
             }
-            ExprKind::NamedConst { def_id, substs, user_ty } => {
-                let user_ty = user_ty.map(|user_ty| {
+            ExprKind::NamedConst { def_id, substs, ref user_ty } => {
+                let user_ty = user_ty.as_ref().map(|box user_ty| {
                     this.canonical_user_type_annotations.push(CanonicalUserTypeAnnotation {
                         span,
-                        user_ty,
+                        user_ty: *user_ty,
                         inferred_ty: ty,
                     })
                 });

compiler/rustc_mir_build/src/build/expr/as_place.rs

@@ -513,7 +513,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 block.and(place_builder)
             }
 
-            ExprKind::PlaceTypeAscription { source, user_ty } => {
+            ExprKind::PlaceTypeAscription { source, ref user_ty } => {
                 let place_builder = unpack!(
                     block = this.expr_as_place(
                         block,
@@ -522,11 +522,11 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                         fake_borrow_temps,
                     )
                 );
-                if let Some(user_ty) = user_ty {
+                if let Some(box user_ty) = user_ty {
                     let annotation_index =
                         this.canonical_user_type_annotations.push(CanonicalUserTypeAnnotation {
                             span: source_info.span,
-                            user_ty,
+                            user_ty: *user_ty,
                             inferred_ty: expr.ty,
                         });
 
@@ -547,15 +547,15 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 }
                 block.and(place_builder)
             }
-            ExprKind::ValueTypeAscription { source, user_ty } => {
+            ExprKind::ValueTypeAscription { source, ref user_ty } => {
                 let source = &this.thir[source];
                 let temp =
                     unpack!(block = this.as_temp(block, source.temp_lifetime, source, mutability));
-                if let Some(user_ty) = user_ty {
+                if let Some(box user_ty) = user_ty {
                     let annotation_index =
                         this.canonical_user_type_annotations.push(CanonicalUserTypeAnnotation {
                             span: source_info.span,
-                            user_ty,
+                            user_ty: *user_ty,
                             inferred_ty: expr.ty,
                         });
                     this.cfg.push(