From: Aman Arora Date: Thu, 2 Jul 2020 03:48:48 +0000 (-0400) Subject: Make hir ProjectionKind more precise X-Git-Url: https://git.lizzy.rs/?a=commitdiff_plain;ds=sidebyside;h=1acccb0f52bc5812ae9431b36b6f8f232a513d1f;p=rust.git Make hir ProjectionKind more precise This commit also categorizing access as Field, Index, or Subslice. Ideas are taken from `mir::ProjectionElem`. Proposed changes: https://github.com/rust-lang/project-rfc-2229/blob/master/hir-place-target.md Closes: https://github.com/rust-lang/project-rfc-2229/issues/1, https://github.com/rust-lang/project-rfc-2229/issues/2 Co-authored-by: Aman Arora Co-authored-by: Chris Pardy Co-authored-by: Dhruv Jauhar --- diff --git a/src/librustc_typeck/expr_use_visitor.rs b/src/librustc_typeck/expr_use_visitor.rs index 4e5ef4329c2..1be32729b1e 100644 --- a/src/librustc_typeck/expr_use_visitor.rs +++ b/src/librustc_typeck/expr_use_visitor.rs @@ -11,8 +11,10 @@ use rustc_hir::def::Res; use rustc_hir::def_id::LocalDefId; use rustc_hir::PatKind; +use rustc_index::vec::Idx; use rustc_infer::infer::InferCtxt; use rustc_middle::ty::{self, adjustment, TyCtxt}; +use rustc_target::abi::VariantIdx; use crate::mem_categorization as mc; use rustc_span::Span; @@ -396,6 +398,7 @@ fn walk_struct_expr( &*with_expr, with_place.clone(), with_field.ty(self.tcx(), substs), + mc::ProjectionKind::Field(f_index as u32, VariantIdx::new(0)), ); self.delegate_consume(&field_place); } diff --git a/src/librustc_typeck/mem_categorization.rs b/src/librustc_typeck/mem_categorization.rs index ac42ce80689..70fe2c2cda5 100644 --- a/src/librustc_typeck/mem_categorization.rs +++ b/src/librustc_typeck/mem_categorization.rs @@ -54,11 +54,14 @@ use rustc_data_structures::fx::FxIndexMap; use rustc_hir as hir; -use rustc_hir::def::{DefKind, Res}; +use rustc_hir::def::{CtorOf, DefKind, Res}; use rustc_hir::def_id::LocalDefId; +use rustc_hir::pat_util::EnumerateAndAdjustIterator; use rustc_hir::PatKind; +use rustc_index::vec::Idx; use rustc_infer::infer::InferCtxt; use rustc_span::Span; +use rustc_target::abi::VariantIdx; use rustc_trait_selection::infer::InferCtxtExt; #[derive(Clone, Debug)] @@ -77,8 +80,20 @@ pub enum PlaceBase { pub enum ProjectionKind { /// A dereference of a pointer, reference or `Box` of the given type Deref, - /// An index or a field - Other, + + /// `B.F` where `B` is the base expression and `F` is + /// the field. The field is identified by which variant + /// it appears in along with a field index. The variant + /// is used for enums. + Field(u32, VariantIdx), + + /// Some index like `B[x]`, where `B` is the base + /// expression. We don't preserve the index `x` because + /// we won't need it. + Index, + + /// A subslice covering a range of values like `B[x..y]`. + Subslice, } #[derive(Clone, Debug)] @@ -406,7 +421,20 @@ fn cat_expr_adjusted_with( hir::ExprKind::Field(ref base, _) => { let base = self.cat_expr(&base)?; debug!("cat_expr(cat_field): id={} expr={:?} base={:?}", expr.hir_id, expr, base); - Ok(self.cat_projection(expr, base, expr_ty)) + + let field_idx = self + .tables + .field_indices() + .get(expr.hir_id) + .cloned() + .expect("Field index not found"); + + Ok(self.cat_projection( + expr, + base, + expr_ty, + ProjectionKind::Field(field_idx as u32, VariantIdx::new(0)), + )) } hir::ExprKind::Index(ref base, _) => { @@ -419,7 +447,7 @@ fn cat_expr_adjusted_with( self.cat_overloaded_place(expr, base) } else { let base = self.cat_expr(&base)?; - Ok(self.cat_projection(expr, base, expr_ty)) + Ok(self.cat_projection(expr, base, expr_ty, ProjectionKind::Index)) } } @@ -533,9 +561,10 @@ fn cat_upvar(&self, hir_id: hir::HirId, var_id: hir::HirId) -> McResult, ty: Ty<'tcx>, + kind: ProjectionKind, ) -> PlaceWithHirId<'tcx> { let mut projections = base_place.place.projections; - projections.push(Projection { kind: ProjectionKind::Other, ty: ty }); + projections.push(Projection { kind: kind, ty: ty }); let ret = PlaceWithHirId::new( node.hir_id(), base_place.place.base_ty, @@ -609,6 +638,75 @@ fn cat_deref( self.cat_pattern_(place, pat, &mut op) } + /// Returns the variant index for an ADT used within a Struct or TupleStruct pattern + /// Here `pat_hir_id` is the HirId of the pattern itself. + fn variant_index_for_adt( + &self, + qpath: &hir::QPath<'_>, + pat_hir_id: hir::HirId, + span: Span, + ) -> McResult { + let res = self.tables.qpath_res(qpath, pat_hir_id); + let ty = self.tables.node_type(pat_hir_id); + let adt_def = match ty.kind { + ty::Adt(adt_def, _) => adt_def, + _ => { + self.tcx() + .sess + .delay_span_bug(span, "struct or tuple struct pattern not applied to an ADT"); + return Err(()); + } + }; + + match res { + Res::Def(DefKind::Variant, variant_id) => Ok(adt_def.variant_index_with_id(variant_id)), + Res::Def(DefKind::Ctor(CtorOf::Variant, ..), variant_ctor_id) => { + Ok(adt_def.variant_index_with_ctor_id(variant_ctor_id)) + } + Res::Def(DefKind::Ctor(CtorOf::Struct, ..), _) + | Res::Def(DefKind::Struct | DefKind::Union | DefKind::TyAlias | DefKind::AssocTy, _) + | Res::SelfCtor(..) + | Res::SelfTy(..) => { + // Structs and Unions have only have one variant. + Ok(VariantIdx::new(0)) + } + _ => bug!("expected ADT path, found={:?}", res), + } + } + + /// Returns the total number of fields in an ADT variant used within a pattern. + /// Here `pat_hir_id` is the HirId of the pattern itself. + fn total_fields_in_adt_variant( + &self, + pat_hir_id: hir::HirId, + variant_index: VariantIdx, + span: Span, + ) -> McResult { + let ty = self.tables.node_type(pat_hir_id); + match ty.kind { + ty::Adt(adt_def, _) => Ok(adt_def.variants[variant_index].fields.len()), + _ => { + self.tcx() + .sess + .delay_span_bug(span, "struct or tuple struct pattern not applied to an ADT"); + return Err(()); + } + } + } + + /// Returns the total number of fields in a tuple used within a Tuple pattern. + /// Here `pat_hir_id` is the HirId of the pattern itself. + fn total_fields_in_tuple(&self, pat_hir_id: hir::HirId, span: Span) -> McResult { + let ty = self.tables.node_type(pat_hir_id); + match ty.kind { + ty::Tuple(substs) => Ok(substs.len()), + _ => { + self.tcx().sess.delay_span_bug(span, "tuple pattern not applied to a tuple"); + return Err(()); + } + } + } + // FIXME(#19596) This is a workaround, but there should be a better way to do this fn cat_pattern_( &self, @@ -679,20 +777,54 @@ fn cat_pattern_( op(&place_with_id, pat); match pat.kind { - PatKind::TupleStruct(_, ref subpats, _) | PatKind::Tuple(ref subpats, _) => { - // S(p1, ..., pN) or (p1, ..., pN) - for subpat in subpats.iter() { + PatKind::Tuple(ref subpats, dots_pos) => { + // (p1, ..., pN) + let total_fields = self.total_fields_in_tuple(pat.hir_id, pat.span)?; + + for (i, subpat) in subpats.iter().enumerate_and_adjust(total_fields, dots_pos) { let subpat_ty = self.pat_ty_adjusted(&subpat)?; - let sub_place = self.cat_projection(pat, place_with_id.clone(), subpat_ty); + let projection_kind = ProjectionKind::Field(i as u32, VariantIdx::new(0)); + let sub_place = + self.cat_projection(pat, place_with_id.clone(), subpat_ty, projection_kind); self.cat_pattern_(sub_place, &subpat, op)?; } } - PatKind::Struct(_, field_pats, _) => { + PatKind::TupleStruct(ref qpath, ref subpats, dots_pos) => { + // S(p1, ..., pN) + let variant_index = self.variant_index_for_adt(qpath, pat.hir_id, pat.span)?; + let total_fields = + self.total_fields_in_adt_variant(pat.hir_id, variant_index, pat.span)?; + + for (i, subpat) in subpats.iter().enumerate_and_adjust(total_fields, dots_pos) { + let subpat_ty = self.pat_ty_adjusted(&subpat)?; + let projection_kind = ProjectionKind::Field(i as u32, variant_index); + let sub_place = + self.cat_projection(pat, place_with_id.clone(), subpat_ty, projection_kind); + self.cat_pattern_(sub_place, &subpat, op)?; + } + } + + PatKind::Struct(ref qpath, field_pats, _) => { // S { f1: p1, ..., fN: pN } + + let variant_index = self.variant_index_for_adt(qpath, pat.hir_id, pat.span)?; + for fp in field_pats { let field_ty = self.pat_ty_adjusted(&fp.pat)?; - let field_place = self.cat_projection(pat, place_with_id.clone(), field_ty); + let field_index = self + .tables + .field_indices() + .get(fp.hir_id) + .cloned() + .expect("no index for a field"); + + let field_place = self.cat_projection( + pat, + place_with_id.clone(), + field_ty, + ProjectionKind::Field(field_index as u32, variant_index), + ); self.cat_pattern_(field_place, &fp.pat, op)?; } } @@ -723,13 +855,23 @@ fn cat_pattern_( return Err(()); } }; - let elt_place = self.cat_projection(pat, place_with_id.clone(), element_ty); + let elt_place = self.cat_projection( + pat, + place_with_id.clone(), + element_ty, + ProjectionKind::Index, + ); for before_pat in before { self.cat_pattern_(elt_place.clone(), &before_pat, op)?; } if let Some(ref slice_pat) = *slice { let slice_pat_ty = self.pat_ty_adjusted(&slice_pat)?; - let slice_place = self.cat_projection(pat, place_with_id, slice_pat_ty); + let slice_place = self.cat_projection( + pat, + place_with_id, + slice_pat_ty, + ProjectionKind::Subslice, + ); self.cat_pattern_(slice_place, &slice_pat, op)?; } for after_pat in after {