diff options
Diffstat (limited to 'gcc/rust/ast/rust-desugar-apit.cc')
-rw-r--r-- | gcc/rust/ast/rust-desugar-apit.cc | 518 |
1 files changed, 518 insertions, 0 deletions
diff --git a/gcc/rust/ast/rust-desugar-apit.cc b/gcc/rust/ast/rust-desugar-apit.cc new file mode 100644 index 0000000..5b9486e --- /dev/null +++ b/gcc/rust/ast/rust-desugar-apit.cc @@ -0,0 +1,518 @@ +// Copyright (C) 2025 Free Software Foundation, Inc. + +// This file is part of GCC. + +// GCC is free software; you can redistribute it and/or modify it under +// the terms of the GNU General Public License as published by the Free +// Software Foundation; either version 3, or (at your option) any later +// version. + +// GCC is distributed in the hope that it will be useful, but WITHOUT ANY +// WARRANTY; without even the implied warranty of MERCHANTABILITY or +// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License +// for more details. + +// You should have received a copy of the GNU General Public License +// along with GCC; see the file COPYING3. If not see +// <http://www.gnu.org/licenses/>. + +#include "rust-desugar-apit.h" +#include "rust-ast.h" +#include "rust-type.h" + +namespace Rust { +namespace AST { + +class DesugarApitType : public DefaultASTVisitor +{ + using DefaultASTVisitor::visit; + +public: + static std::pair<AST::Type *, std::vector<std::unique_ptr<GenericParam>>> + Desugar (AST::Type &type) + { + DesugarApitType visitor (&type); + type.accept_vis (visitor); + rust_assert (visitor.translated != nullptr); + return std::make_pair (visitor.translated, + std::move (visitor.implicit_generic_params)); + } + + // Generate a unique impl trait parameter name + static Identifier get_impl_name () + { + static size_t counter = 0; + return Identifier ("Impl_" + std::to_string (counter++)); + } + + // these can hold other types + void visit (AST::TupleType &tuple) override + { + for (auto &elem : tuple.get_elems ()) + { + auto &type = *elem.get (); + auto desugar = Desugar (type); + auto tt = desugar.first; + + auto &implicit_generics = desugar.second; + if (implicit_generics.empty ()) + continue; + + if (tt != elem.get ()) + elem = std::unique_ptr<Type> (tt); + + for (auto &implicit_generic : implicit_generics) + implicit_generic_params.push_back (std::move (implicit_generic)); + } + } + + void visit (AST::ArrayType &type) override + { + auto &element_type = type.get_element_type (); + auto desugar = Desugar (*element_type); + auto tt = desugar.first; + + auto &implicit_generics = desugar.second; + if (implicit_generics.empty ()) + return; + + if (tt != element_type.get ()) + element_type = std::unique_ptr<AST::Type> (tt); + + for (auto &implicit_generic : implicit_generics) + implicit_generic_params.push_back (std::move (implicit_generic)); + } + + void visit (AST::ReferenceType &type) override + { + // Get a reference to the current type for in-place modification + auto &referenced_type = type.get_type_referenced (); + auto desugar = Desugar (referenced_type); + auto tt = desugar.first; + + auto &implicit_generics = desugar.second; + if (implicit_generics.empty ()) + return; + + // Update the reference type's contents rather than creating a new one + if (&referenced_type != tt) + { + std::unique_ptr<AST::TypeNoBounds> new_type_no_bounds ( + static_cast<AST::TypeNoBounds *> (tt)); + type.get_type_ptr () = std::move (new_type_no_bounds); + } + + // Collect all the implicit generic parameters we found + for (auto &implicit_generic : implicit_generics) + implicit_generic_params.push_back (std::move (implicit_generic)); + } + + void visit (AST::RawPointerType &type) override + { + auto &pointed_type = type.get_type_pointed_to (); + auto desugar = Desugar (pointed_type); + auto tt = desugar.first; + + auto &implicit_generics = desugar.second; + if (implicit_generics.empty ()) + return; + + // Update the pointer's inner type directly using the new accessor + if (&pointed_type != tt) + { + std::unique_ptr<AST::TypeNoBounds> new_type_no_bounds ( + static_cast<AST::TypeNoBounds *> (tt)); + type.get_type_ptr () = std::move (new_type_no_bounds); + } + + // Collect all the implicit generic parameters we found + for (auto &implicit_generic : implicit_generics) + implicit_generic_params.push_back (std::move (implicit_generic)); + } + + void visit (AST::SliceType &type) override + { + auto &element_type = type.get_elem_type (); + auto desugar = Desugar (element_type); + auto tt = desugar.first; + + auto &implicit_generics = desugar.second; + if (implicit_generics.empty ()) + return; + + if (&element_type != tt) + { + std::unique_ptr<AST::Type> new_elem_type (tt); + type.get_elem_type_ptr () = std::move (new_elem_type); + } + + // Collect all the implicit generic parameters we found + for (auto &implicit_generic : implicit_generics) + implicit_generic_params.push_back (std::move (implicit_generic)); + } + + void visit (AST::ParenthesisedType &type) override + { + auto &inner_type_ptr = type.get_type_in_parens (); + auto desugar = Desugar (*inner_type_ptr); + auto tt = desugar.first; + + auto &implicit_generics = desugar.second; + if (implicit_generics.empty ()) + return; + + if (inner_type_ptr.get () != tt) + { + std::unique_ptr<AST::Type> new_inner_type (tt); + inner_type_ptr = std::move (new_inner_type); + } + + // Collect all the implicit generic parameters we found + for (auto &implicit_generic : implicit_generics) + implicit_generic_params.push_back (std::move (implicit_generic)); + } + + // this is where the desugar happens + void visit (AST::ImplTraitType &type) override + { + // Generate a unique name using the static method + auto ident = get_impl_name (); + + // Create a type path for the new generic parameter + // Create a SimplePathSegment with the identifier string + auto simple_seg = SimplePathSegment (ident.as_string (), type.get_locus ()); + // Create a vector of SimplePathSegments for SimplePath constructor + std::vector<SimplePathSegment> simple_segs = {simple_seg}; + // Create a SimplePath + auto simple_path = SimplePath (simple_segs, false, type.get_locus ()); + + // Convert to TypePath by creating path segments + std::vector<std::unique_ptr<TypePathSegment>> segments; + segments.push_back (std::unique_ptr<TypePathSegment> (new TypePathSegment ( + PathIdentSegment (ident.as_string (), type.get_locus ()), false, + type.get_locus ()))); + + // Create TypePath from segments + auto type_path + = new TypePath (std::move (segments), type.get_locus (), false); + + // Convert bounds from impl trait to generic parameter bounds + std::vector<std::unique_ptr<TypeParamBound>> bounds; + for (auto &bound : type.get_type_param_bounds ()) + bounds.push_back (bound->clone_type_param_bound ()); + + // Create the new generic parameter + auto generic_param = std::unique_ptr<TypeParam> ( + new TypeParam (ident, type.get_locus (), std::move (bounds), nullptr, {}, + true /*from impl trait*/)); + + // Store the generic parameter to be added to the function signature + implicit_generic_params.push_back (std::move (generic_param)); + + // Replace impl trait with the new type parameter + translated = type_path; + } + + void visit (AST::ImplTraitTypeOneBound &type) override + { + // Generate a unique name using the static method + auto ident = get_impl_name (); + + // Create a type path for the new generic parameter + // Create a SimplePathSegment with the identifier string + auto simple_seg = SimplePathSegment (ident.as_string (), type.get_locus ()); + // Create a vector of SimplePathSegments for SimplePath constructor + std::vector<SimplePathSegment> simple_segs = {simple_seg}; + // Create a SimplePath + auto simple_path = SimplePath (simple_segs, false, type.get_locus ()); + + // Convert to TypePath by creating path segments + std::vector<std::unique_ptr<TypePathSegment>> segments; + segments.push_back (std::unique_ptr<TypePathSegment> (new TypePathSegment ( + PathIdentSegment (ident.as_string (), type.get_locus ()), false, + type.get_locus ()))); + + // Create TypePath from segments + auto type_path + = new TypePath (std::move (segments), type.get_locus (), false); + + // Convert the bound to a generic parameter bound + std::vector<std::unique_ptr<TypeParamBound>> bounds; + bounds.push_back (std::move (type.get_trait_bound ())); + + // Create the new generic parameter + auto generic_param = std::unique_ptr<TypeParam> ( + new TypeParam (ident, type.get_locus (), std::move (bounds), nullptr, {}, + true /*from impl trait*/)); + + // Store the generic parameter to be added to the function signature + implicit_generic_params.push_back (std::move (generic_param)); + + // Replace impl trait with the new type parameter + translated = type_path; + } + +private: + DesugarApitType (AST::Type *base) + : translated (base), implicit_generic_params () + {} + + AST::Type *translated; + std::vector<std::unique_ptr<GenericParam>> implicit_generic_params; +}; + +// --------- + +class ApitBoundProcessor +{ +public: + ApitBoundProcessor ( + WhereClause &where_clause, + std::vector<std::unique_ptr<GenericParam>> &generic_params) + : where_clause (where_clause), generic_params (generic_params) + {} + + void go (std::vector<std::unique_ptr<GenericParam>> &implicit_generics) + { + // some desugars are more complex so imagine this case + // + // pub fn foo(_value: impl Bar<Baz = impl Foo>) -> i32 { + // 15 + // } + // + // this needs to become: + // + // pub fn foo<T, U>(_value: T) -> i32 + // where + // T: Bar<Baz = U>, + // U: Foo, + // { + // 15 + // } + // + // so we need to walk all the implicit generics and the trait bounds paths + // for more generics + + for (auto &implicit_generic : implicit_generics) + { + switch (implicit_generic->get_kind ()) + { + case GenericParam::Kind::Type: { + TypeParam &p + = *static_cast<TypeParam *> (implicit_generic.get ()); + + process_type_param (p); + generic_params.push_back (std::move (implicit_generic)); + for (auto &synth : synthetic_params) + generic_params.push_back (std::move (synth)); + synthetic_params.clear (); + } + break; + + default: + generic_params.push_back (std::move (implicit_generic)); + break; + } + } + } + +private: + void process_type_param (TypeParam &p) + { + auto &bounds = p.get_type_param_bounds (); + std::vector<size_t> bounds_to_remove; + for (size_t i = 0; i < bounds.size (); i++) + { + auto &tb = bounds[i]; + switch (tb->get_bound_type ()) + { + case TypeParamBound::TypeParamBoundType::TRAIT: { + TraitBound &ttb = *static_cast<TraitBound *> (tb.get ()); + TypePath &path = ttb.get_type_path (); + bool deusgared = process_type_path (p, ttb, path); + if (deusgared) + bounds_to_remove.push_back (i); + } + + default: + break; + } + } + for (auto it = bounds_to_remove.rbegin (); it != bounds_to_remove.rend (); + ++it) + bounds.erase (bounds.begin () + *it); + } + + bool process_type_path (TypeParam &p, TraitBound &parent, TypePath &path) + { + bool desugared = false; + for (auto &segment : path.get_segments ()) + { + switch (segment->get_type ()) + { + case TypePathSegment::SegmentType::GENERIC: { + TypePathSegmentGeneric &seg + = *static_cast<TypePathSegmentGeneric *> (segment.get ()); + desugared |= process_generic_segment (p, parent, path, seg); + } + + default: + break; + } + } + return desugared; + } + + bool process_generic_segment (TypeParam &p, TraitBound &parent, + TypePath &path, TypePathSegmentGeneric &seg) + { + // we need to look for any impl types as default arguments in any generics + // and remove this index from the generic arguments by using a where + // constraint instead + + std::vector<std::unique_ptr<WhereClauseItem>> new_clauses; + GenericArgs &generic_args = seg.get_generic_args (); + std::vector<std::reference_wrapper<const GenericArgsBinding>> + bindings_desugared; + std::vector<GenericArgsBinding> &bindings + = generic_args.get_binding_args (); + + for (auto &generic : bindings) + { + auto &t = generic.get_type (); + auto translated = DesugarApitType::Desugar (t); + auto tt = translated.first; + + auto &implicit_generics = translated.second; + if (implicit_generics.empty ()) + continue; + + if (tt != &t) + { + bindings_desugared.push_back (generic); + generic.get_type_ptr () = std::unique_ptr<Type> (tt); + } + + for (auto &implicit_generic : implicit_generics) + { + switch (implicit_generic->get_kind ()) + { + case GenericParam::Kind::Type: { + TypeParam &tp + = *static_cast<TypeParam *> (implicit_generic.get ()); + + std::vector<std::unique_ptr<TypeParamBound>> + type_param_bounds; + for (auto &b : tp.get_type_param_bounds ()) + type_param_bounds.push_back (std::move (b)); + tp.get_type_param_bounds ().clear (); + + // add synthetic parameter for this + synthetic_params.push_back (std::move (implicit_generic)); + + auto bound_type_path + = get_type_for_identifier (tp.get_type_representation ()); + + auto clause = new TypeBoundWhereClauseItem ( + {}, std::move (bound_type_path), + std::move (type_param_bounds), tp.get_locus ()); + std::unique_ptr<WhereClauseItem> clause_item + = std::unique_ptr<WhereClauseItem> (clause); + new_clauses.push_back (std::move (clause_item)); + } + break; + + default: + synthetic_params.push_back (std::move (implicit_generic)); + break; + } + } + } + + std::vector<std::unique_ptr<TypeParamBound>> type_param_bounds; + auto bound = std::unique_ptr<TypeParamBound> (new TraitBound (parent)); + type_param_bounds.push_back (std::move (bound)); + auto parent_type_path + = get_type_for_identifier (p.get_type_representation ()); + auto clause + = new TypeBoundWhereClauseItem ({}, std::move (parent_type_path), + std::move (type_param_bounds), + parent.get_locus ()); + std::unique_ptr<WhereClauseItem> clause_item + = std::unique_ptr<WhereClauseItem> (clause); + where_clause.get_items ().push_back (std::move (clause_item)); + + for (auto &where_item : new_clauses) + where_clause.get_items ().push_back (std::move (where_item)); + + return !bindings_desugared.empty (); + } + + static std::unique_ptr<Type> get_type_for_identifier (const Identifier &ident) + { + auto simple_seg + = SimplePathSegment (ident.as_string (), ident.get_locus ()); + std::vector<SimplePathSegment> simple_segs = {simple_seg}; + auto simple_path = SimplePath (simple_segs, false, ident.get_locus ()); + std::vector<std::unique_ptr<TypePathSegment>> segments; + segments.push_back (std::unique_ptr<TypePathSegment> (new TypePathSegment ( + PathIdentSegment (ident.as_string (), ident.get_locus ()), false, + ident.get_locus ()))); + auto type_path = new TypePath (std::move (segments), ident.get_locus ()); + return std::unique_ptr<Type> (type_path); + } + +private: + WhereClause &where_clause; + std::vector<std::unique_ptr<GenericParam>> &generic_params; + + // mutates + std::vector<std::unique_ptr<GenericParam>> synthetic_params; +}; + +// --------- + +DesugarApit::DesugarApit () {} + +void +DesugarApit::go (AST::Crate &crate) +{ + DefaultASTVisitor::visit (crate); +} + +void +DesugarApit::visit (AST::Function &function) +{ + if (!function.has_function_params ()) + return; + + auto &fn_params = function.get_function_params (); + for (auto ¶m : fn_params) + { + if (param->is_variadic () || param->is_self ()) + continue; + + auto *p = param.get (); + auto &fp = *static_cast<AST::FunctionParam *> (p); + auto &type = fp.get_type (); + + auto translated = DesugarApitType::Desugar (type); + auto tt = translated.first; + + auto &implicit_generics = translated.second; + if (implicit_generics.empty ()) + continue; + + if (fp.get_type_ptr ().get () != tt) + { + fp.get_type_ptr () = std::unique_ptr<AST::Type> (tt); + } + + ApitBoundProcessor processor (function.get_where_clause (), + function.get_generic_params ()); + processor.go (implicit_generics); + } +} + +} // namespace AST +} // namespace Rust |