[gcc r14-8562] gccrs: late: Start storing mappings properly in the resolver

[Arthur Cohen <cohenarthur@gcc.gnu.org>]

https://gcc.gnu.org/g:0f0ec052b4ad1fb7250a5ad1ec00d276fdc29a09

commit r14-8562-g0f0ec052b4ad1fb7250a5ad1ec00d276fdc29a09
Author: Arthur Cohen <arthur.cohen@embecosm.com>
Date:   Tue Aug 22 17:29:05 2023 +0200

    gccrs: late: Start storing mappings properly in the resolver
    
    gcc/rust/ChangeLog:
    
            * resolve/rust-late-name-resolver-2.0.cc (Late::visit): Store mappings
            after having resolved them.
            * resolve/rust-late-name-resolver-2.0.h: Add `TypePath` visitor.

Diff:
---
 gcc/rust/resolve/rust-late-name-resolver-2.0.cc | 33 +++++++++++++++++++++----
 gcc/rust/resolve/rust-late-name-resolver-2.0.h  |  1 +
 2 files changed, 29 insertions(+), 5 deletions(-)

diff --git a/gcc/rust/resolve/rust-late-name-resolver-2.0.cc b/gcc/rust/resolve/rust-late-name-resolver-2.0.cc
index 3236886f37d4..5f70f5755824 100644
--- a/gcc/rust/resolve/rust-late-name-resolver-2.0.cc
+++ b/gcc/rust/resolve/rust-late-name-resolver-2.0.cc
@@ -20,6 +20,7 @@
 #include "rust-ast-full.h"
 #include "rust-late-name-resolver-2.0.h"
 #include "rust-default-resolver.h"
+#include "rust-path.h"
 #include "rust-tyty.h"
 #include "rust-hir-type-check.h"
 
@@ -121,11 +122,24 @@ Late::visit (AST::IdentifierExpr &expr)
 {
   // TODO: same thing as visit(PathInExpression) here?
 
+  tl::optional<NodeId> resolved = tl::nullopt;
   auto label = ctx.labels.get (expr.get_ident ());
   auto value = ctx.values.get (expr.get_ident ());
 
-  rust_debug ("[ARTHUR] label: %d", label ? *label : -1);
-  rust_debug ("[ARTHUR] value: %d", value ? *value : -1);
+  if (label)
+    resolved = label;
+  else if (value)
+    resolved = value;
+  // TODO: else emit error?
+
+  ctx.map_usage (expr.get_node_id (), *resolved);
+
+  // in the old resolver, resolutions are kept in the resolver, not the mappings
+  // :/ how do we deal with that?
+  // ctx.mappings.insert_resolved_name(expr, resolved);
+
+  // For empty types, do we perform a lookup in ctx.types or should the
+  // toplevel instead insert a name in ctx.values? (like it currently does)
 }
 
 void
@@ -136,11 +150,20 @@ Late::visit (AST::PathInExpression &expr)
   // do we emit it in `get<Namespace::Labels>`?
 
   auto label = ctx.labels.resolve_path (expr.get_segments ());
-
   auto value = ctx.values.resolve_path (expr.get_segments ());
+}
+
+void
+Late::visit (AST::TypePath &type)
+{
+  // should we add type path resolution in `ForeverStack` directly? Since it's
+  // quite more complicated.
+  // maybe we can overload `resolve_path<Namespace::Types>` to only do
+  // typepath-like path resolution? that sounds good
+
+  auto resolved = ctx.types.get (type.get_segments ().back ()->as_string ());
 
-  rust_debug ("[ARTHUR] label: %d", label ? *label : -1);
-  rust_debug ("[ARTHUR] value: %d", value ? *value : -1);
+  ctx.map_usage (type.get_node_id (), *resolved);
 }
 
 } // namespace Resolver2_0
diff --git a/gcc/rust/resolve/rust-late-name-resolver-2.0.h b/gcc/rust/resolve/rust-late-name-resolver-2.0.h
index f54bbf2eea4f..15940d053aed 100644
--- a/gcc/rust/resolve/rust-late-name-resolver-2.0.h
+++ b/gcc/rust/resolve/rust-late-name-resolver-2.0.h
@@ -45,6 +45,7 @@ public:
   // resolutions
   void visit (AST::IdentifierExpr &) override;
   void visit (AST::PathInExpression &) override;
+  void visit (AST::TypePath &) override;
 
 private:
   /* Setup Rust's builtin types (u8, i32, !...) in the resolver */