Refactor mappings class and HIR lowering to be consistent

In order to support loading extern crates and use statements we needed to
clarify the usage of NodeId and HirId within gccrs. Each of these id's were
nested behind the CrateNum but the type resolution, linting and code-gen
passes do not support that level of nesting.

In order to get metadata exports and imports working lets focus on gccrs
supporting compilation of a single crate at a time. This means the crate
prefix only matters for imports and limits the complexity here. Down the
line there might be a way to leverage DefId's for all Path resolution
which could solve this problem but significant refactoring would be
required here to do this properly and its not nessecary for a basic working
rust compiler.

1 files changed, 65 insertions, 28 deletions

diff --git a/gcc/rust/resolve/rust-ast-resolve-toplevel.h b/gcc/rust/resolve/rust-ast-resolve-toplevel.h
index 7aacc0a..352faac 100644
--- a/gcc/rust/resolve/rust-ast-resolve-toplevel.h
+++ b/gcc/rust/resolve/rust-ast-resolve-toplevel.h
@@ -24,6 +24,7 @@
 #include "rust-ast-resolve-implitem.h"
 #include "rust-ast-full.h"
 #include "rust-name-resolver.h"
+#include "rust-session-manager.h"
 
 namespace Rust {
 namespace Resolver {
@@ -72,8 +73,7 @@ public:
 
     resolver->pop_module_scope ();
 
-    mappings->insert_canonical_path (mappings->get_current_crate (),
-				     module.get_node_id (), cpath);
+    mappings->insert_canonical_path (module.get_node_id (), cpath);
   }
 
   void visit (AST::TypeAlias &alias) override
@@ -93,8 +93,7 @@ public:
 
     NodeId current_module = resolver->peek_current_module_scope ();
     mappings->insert_module_child_item (current_module, talias);
-    mappings->insert_canonical_path (mappings->get_current_crate (),
-				     alias.get_node_id (), cpath);
+    mappings->insert_canonical_path (alias.get_node_id (), cpath);
   }
 
   void visit (AST::TupleStruct &struct_decl) override
@@ -114,8 +113,7 @@ public:
 
     NodeId current_module = resolver->peek_current_module_scope ();
     mappings->insert_module_child_item (current_module, decl);
-    mappings->insert_canonical_path (mappings->get_current_crate (),
-				     struct_decl.get_node_id (), cpath);
+    mappings->insert_canonical_path (struct_decl.get_node_id (), cpath);
   }
 
   void visit (AST::Enum &enum_decl) override
@@ -138,8 +136,7 @@ public:
 
     NodeId current_module = resolver->peek_current_module_scope ();
     mappings->insert_module_child_item (current_module, decl);
-    mappings->insert_canonical_path (mappings->get_current_crate (),
-				     enum_decl.get_node_id (), cpath);
+    mappings->insert_canonical_path (enum_decl.get_node_id (), cpath);
   }
 
   void visit (AST::EnumItem &item) override
@@ -157,8 +154,7 @@ public:
 	rust_error_at (r, "redefined multiple times");
       });
 
-    mappings->insert_canonical_path (mappings->get_current_crate (),
-				     item.get_node_id (), cpath);
+    mappings->insert_canonical_path (item.get_node_id (), cpath);
   }
 
   void visit (AST::EnumItemTuple &item) override
@@ -176,8 +172,7 @@ public:
 	rust_error_at (r, "redefined multiple times");
       });
 
-    mappings->insert_canonical_path (mappings->get_current_crate (),
-				     item.get_node_id (), cpath);
+    mappings->insert_canonical_path (item.get_node_id (), cpath);
   }
 
   void visit (AST::EnumItemStruct &item) override
@@ -195,8 +190,7 @@ public:
 	rust_error_at (r, "redefined multiple times");
       });
 
-    mappings->insert_canonical_path (mappings->get_current_crate (),
-				     item.get_node_id (), cpath);
+    mappings->insert_canonical_path (item.get_node_id (), cpath);
   }
 
   void visit (AST::EnumItemDiscriminant &item) override
@@ -214,8 +208,7 @@ public:
 	rust_error_at (r, "redefined multiple times");
       });
 
-    mappings->insert_canonical_path (mappings->get_current_crate (),
-				     item.get_node_id (), cpath);
+    mappings->insert_canonical_path (item.get_node_id (), cpath);
   }
 
   void visit (AST::StructStruct &struct_decl) override
@@ -235,8 +228,7 @@ public:
 
     NodeId current_module = resolver->peek_current_module_scope ();
     mappings->insert_module_child_item (current_module, decl);
-    mappings->insert_canonical_path (mappings->get_current_crate (),
-				     struct_decl.get_node_id (), cpath);
+    mappings->insert_canonical_path (struct_decl.get_node_id (), cpath);
   }
 
   void visit (AST::Union &union_decl) override
@@ -256,8 +248,7 @@ public:
 
     NodeId current_module = resolver->peek_current_module_scope ();
     mappings->insert_module_child_item (current_module, decl);
-    mappings->insert_canonical_path (mappings->get_current_crate (),
-				     union_decl.get_node_id (), cpath);
+    mappings->insert_canonical_path (union_decl.get_node_id (), cpath);
   }
 
   void visit (AST::StaticItem &var) override
@@ -277,8 +268,7 @@ public:
 
     NodeId current_module = resolver->peek_current_module_scope ();
     mappings->insert_module_child_item (current_module, decl);
-    mappings->insert_canonical_path (mappings->get_current_crate (),
-				     var.get_node_id (), cpath);
+    mappings->insert_canonical_path (var.get_node_id (), cpath);
   }
 
   void visit (AST::ConstantItem &constant) override
@@ -298,8 +288,7 @@ public:
 
     NodeId current_module = resolver->peek_current_module_scope ();
     mappings->insert_module_child_item (current_module, decl);
-    mappings->insert_canonical_path (mappings->get_current_crate (),
-				     constant.get_node_id (), cpath);
+    mappings->insert_canonical_path (constant.get_node_id (), cpath);
   }
 
   void visit (AST::Function &function) override
@@ -319,8 +308,7 @@ public:
 
     NodeId current_module = resolver->peek_current_module_scope ();
     mappings->insert_module_child_item (current_module, decl);
-    mappings->insert_canonical_path (mappings->get_current_crate (),
-				     function.get_node_id (), cpath);
+    mappings->insert_canonical_path (function.get_node_id (), cpath);
   }
 
   void visit (AST::InherentImpl &impl_block) override
@@ -385,8 +373,7 @@ public:
 
     NodeId current_module = resolver->peek_current_module_scope ();
     mappings->insert_module_child_item (current_module, decl);
-    mappings->insert_canonical_path (mappings->get_current_crate (),
-				     trait.get_node_id (), cpath);
+    mappings->insert_canonical_path (trait.get_node_id (), cpath);
   }
 
   void visit (AST::ExternBlock &extern_block) override
@@ -397,6 +384,56 @@ public:
       }
   }
 
+  void visit (AST::ExternCrate &extern_crate) override
+  {
+    if (extern_crate.is_marked_for_strip ())
+      return;
+
+    NodeId resolved_crate = UNKNOWN_NODEID;
+    if (extern_crate.references_self ())
+      {
+	// FIXME
+	// then this resolves to current crate_node_id
+	// need to expose on the session object a reference to the current
+	// AST::Crate& to get node_id
+	gcc_unreachable ();
+	return;
+      }
+    else
+      {
+	rust_debug_loc (extern_crate.get_locus (), "load extern crate: [%s]",
+			extern_crate.as_string ().c_str ());
+
+	Session &session = Session::get_instance ();
+	resolved_crate
+	  = session.load_extern_crate (extern_crate.get_referenced_crate ());
+      }
+
+    if (resolved_crate == UNKNOWN_NODEID)
+      {
+	rust_error_at (extern_crate.get_locus (), "failed to resolve crate");
+	return;
+      }
+
+    // mark the node as resolved
+    resolver->insert_resolved_name (extern_crate.get_node_id (),
+				    resolved_crate);
+
+    // does it has an as clause
+    if (extern_crate.has_as_clause ())
+      {
+	auto decl = CanonicalPath::new_seg (extern_crate.get_node_id (),
+					    extern_crate.get_as_clause ());
+	resolver->get_type_scope ().insert (
+	  decl, extern_crate.get_node_id (), extern_crate.get_locus (), false,
+	  [&] (const CanonicalPath &, NodeId, Location locus) -> void {
+	    RichLocation r (extern_crate.get_locus ());
+	    r.add_range (locus);
+	    rust_error_at (r, "redefined multiple times");
+	  });
+      }
+  }
+
 private:
   ResolveTopLevel (const CanonicalPath &prefix,
 		   const CanonicalPath &canonical_prefix)