[gcc/devel/rust/master] hir: Add ConstGenericArg and lower them properly

[gcc/devel/rust/master] hir: Add ConstGenericArg and lower them properly

[Thomas Schwinge]

https://gcc.gnu.org/g:6e5468e256dd06eb6988a0eca37c86bc52722457

commit 6e5468e256dd06eb6988a0eca37c86bc52722457
Author: Arthur Cohen <arthur.cohen@embecosm.com>
Date:   Mon Jun 20 16:50:46 2022 +0200

    hir: Add ConstGenericArg and lower them properly

Diff:
---
 gcc/rust/ast/rust-path.h            |  2 ++
 gcc/rust/hir/rust-ast-lower-base.cc | 35 ++++++++++++-------------
 gcc/rust/hir/tree/rust-hir-path.h   | 52 ++++++++++++++++++++++++++++++-------
 3 files changed, 62 insertions(+), 27 deletions(-)

diff --git a/gcc/rust/ast/rust-path.h b/gcc/rust/ast/rust-path.h
index 5642226afce..03758d01dde 100644
--- a/gcc/rust/ast/rust-path.h
+++ b/gcc/rust/ast/rust-path.h
@@ -189,6 +189,8 @@ public:
 
   Kind get_kind () const { return kind; }
 
+  std::unique_ptr<AST::Expr> &get_expression () { return expression; }
+
   std::string as_string () const
   {
     switch (get_kind ())
diff --git a/gcc/rust/hir/rust-ast-lower-base.cc b/gcc/rust/hir/rust-ast-lower-base.cc
index 68bec882daa..7e80f811092 100644
--- a/gcc/rust/hir/rust-ast-lower-base.cc
+++ b/gcc/rust/hir/rust-ast-lower-base.cc
@@ -612,8 +612,19 @@ ASTLoweringBase::lower_generic_args (AST::GenericArgs &args)
       type_args.push_back (std::unique_ptr<HIR::Type> (t));
     }
 
+  std::vector<HIR::ConstGenericArg> const_args;
+  for (auto &const_arg : args.get_const_args ())
+    const_args.emplace_back (HIR::ConstGenericArg (
+      std::unique_ptr<HIR::Expr> (
+	ASTLoweringExpr::translate (const_arg.get_expression ().get ())),
+      Location ()));
+
+  // FIXME:
+  // const_arg.get_locus ());
+
   return HIR::GenericArgs (std::move (lifetime_args), std::move (type_args),
-			   std::move (binding_args), args.get_locus ());
+			   std::move (binding_args), std::move (const_args),
+			   args.get_locus ());
 }
 
 HIR::SelfParam
@@ -650,29 +661,17 @@ ASTLowerTypePath::visit (AST::TypePathSegmentGeneric &segment)
   bool has_separating_scope_resolution
     = segment.get_separating_scope_resolution ();
 
-  std::vector<HIR::Lifetime> lifetime_args;
-  for (auto &lifetime : segment.get_generic_args ().get_lifetime_args ())
-    {
-      HIR::Lifetime l = lower_lifetime (lifetime);
-      lifetime_args.push_back (std::move (l));
-    }
-
-  std::vector<std::unique_ptr<HIR::Type>> type_args;
-  for (auto &type : segment.get_generic_args ().get_type_args ())
-    {
-      HIR::Type *t = ASTLoweringType::translate (type.get ());
-      type_args.push_back (std::unique_ptr<HIR::Type> (t));
-    }
+  auto generic_args = lower_generic_args (segment.get_generic_args ());
 
   auto crate_num = mappings->get_current_crate ();
   auto hirid = mappings->get_next_hir_id (crate_num);
   Analysis::NodeMapping mapping (crate_num, segment.get_node_id (), hirid,
 				 UNKNOWN_LOCAL_DEFID);
 
-  translated_segment = new HIR::TypePathSegmentGeneric (
-    std::move (mapping), segment_name, has_separating_scope_resolution,
-    std::move (lifetime_args), std::move (type_args), std::move (binding_args),
-    segment.get_locus ());
+  translated_segment
+    = new HIR::TypePathSegmentGeneric (std::move (mapping), segment_name,
+				       has_separating_scope_resolution,
+				       generic_args, segment.get_locus ());
 }
 
 void
diff --git a/gcc/rust/hir/tree/rust-hir-path.h b/gcc/rust/hir/tree/rust-hir-path.h
index b18bf1dde22..a5006f5f4c7 100644
--- a/gcc/rust/hir/tree/rust-hir-path.h
+++ b/gcc/rust/hir/tree/rust-hir-path.h
@@ -112,12 +112,41 @@ public:
   Location get_locus () const { return locus; }
 };
 
+class ConstGenericArg
+{
+  // FIXME: Do we need to disambiguate or no? We should be able to disambiguate
+  // at name-resolution, hence no need for ambiguities here
+
+public:
+  ConstGenericArg (std::unique_ptr<Expr> expression, Location locus)
+    : expression (std::move (expression)), locus (locus)
+  {}
+
+  ConstGenericArg (const ConstGenericArg &other) : locus (other.locus)
+  {
+    expression = other.expression->clone_expr ();
+  }
+
+  ConstGenericArg operator= (const ConstGenericArg &other)
+  {
+    expression = other.expression->clone_expr ();
+    locus = other.locus;
+
+    return *this;
+  }
+
+private:
+  std::unique_ptr<Expr> expression;
+  Location locus;
+};
+
 // Generic arguments allowed in each path expression segment - inline?
 struct GenericArgs
 {
   std::vector<Lifetime> lifetime_args;
   std::vector<std::unique_ptr<Type> > type_args;
   std::vector<GenericArgsBinding> binding_args;
+  std::vector<ConstGenericArg> const_args;
   Location locus;
 
 public:
@@ -130,18 +159,21 @@ public:
 
   GenericArgs (std::vector<Lifetime> lifetime_args,
 	       std::vector<std::unique_ptr<Type> > type_args,
-	       std::vector<GenericArgsBinding> binding_args, Location locus)
+	       std::vector<GenericArgsBinding> binding_args,
+	       std::vector<ConstGenericArg> const_args, Location locus)
     : lifetime_args (std::move (lifetime_args)),
       type_args (std::move (type_args)),
-      binding_args (std::move (binding_args)), locus (locus)
+      binding_args (std::move (binding_args)),
+      const_args (std::move (const_args)), locus (locus)
   {}
 
   // copy constructor with vector clone
   GenericArgs (GenericArgs const &other)
     : lifetime_args (other.lifetime_args), binding_args (other.binding_args),
-      locus (other.locus)
+      const_args (other.const_args), locus (other.locus)
   {
     type_args.reserve (other.type_args.size ());
+
     for (const auto &e : other.type_args)
       type_args.push_back (e->clone_type ());
   }
@@ -153,6 +185,7 @@ public:
   {
     lifetime_args = other.lifetime_args;
     binding_args = other.binding_args;
+    const_args = other.const_args;
     locus = other.locus;
 
     type_args.reserve (other.type_args.size ());
@@ -169,9 +202,7 @@ public:
   // Creates an empty GenericArgs (no arguments)
   static GenericArgs create_empty (Location locus = Location ())
   {
-    return GenericArgs (std::vector<Lifetime> (),
-			std::vector<std::unique_ptr<Type> > (),
-			std::vector<GenericArgsBinding> (), locus);
+    return GenericArgs ({}, {}, {}, {}, locus);
   }
 
   bool is_empty () const
@@ -188,6 +219,8 @@ public:
 
   std::vector<GenericArgsBinding> &get_binding_args () { return binding_args; }
 
+  std::vector<ConstGenericArg> &get_const_args () { return const_args; }
+
   Location get_locus () const { return locus; }
 };
 
@@ -464,12 +497,13 @@ public:
 			  std::vector<Lifetime> lifetime_args,
 			  std::vector<std::unique_ptr<Type> > type_args,
 			  std::vector<GenericArgsBinding> binding_args,
+			  std::vector<ConstGenericArg> const_args,
 			  Location locus)
     : TypePathSegment (std::move (mappings), std::move (segment_name),
 		       has_separating_scope_resolution, locus),
-      generic_args (GenericArgs (std::move (lifetime_args),
-				 std::move (type_args),
-				 std::move (binding_args), locus))
+      generic_args (
+	GenericArgs (std::move (lifetime_args), std::move (type_args),
+		     std::move (binding_args), std::move (const_args), locus))
   {}
 
   std::string as_string () const override;