[gcc r14-8104] gccrs: Add array length to the proc macro buffer

[Arthur Cohen]

https://gcc.gnu.org/g:068bdc3c6141833d533fd99234578c86658c0576

commit r14-8104-g068bdc3c6141833d533fd99234578c86658c0576
Author: Pierre-Emmanuel Patry <pierre-emmanuel.patry@embecosm.com>
Date:   Thu Oct 5 12:28:38 2023 +0200

    gccrs: Add array length to the proc macro buffer
    
    The compiler cannot infer the array length from the type, we should
    therefore hand it the information. The proc macro buffer missed that
    information.
    
    gcc/rust/ChangeLog:
    
            * backend/rust-compile.cc (proc_macro_buffer): Update type builder with
            array length information.
            (proc_macro_array): Update type initializer with array length
            information.
    
    Signed-off-by: Pierre-Emmanuel Patry <pierre-emmanuel.patry@embecosm.com>

Diff:
---
 gcc/rust/backend/rust-compile.cc | 21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/gcc/rust/backend/rust-compile.cc b/gcc/rust/backend/rust-compile.cc
index f400d6916aa..d0052feb571 100644
--- a/gcc/rust/backend/rust-compile.cc
+++ b/gcc/rust/backend/rust-compile.cc
@@ -207,8 +207,14 @@ proc_macro ()
 tree
 proc_macro_buffer (tree proc_macro_type, size_t total_macro)
 {
-  // FIXME: Add the array length, build a structure containing an array
-  return build_array_type_nelts (proc_macro_type, total_macro);
+  auto length_field = Backend::typed_identifier ("length", unsigned_type_node,
+						 BUILTINS_LOCATION);
+
+  auto array_type = build_array_type_nelts (proc_macro_type, total_macro);
+  auto macros_field
+    = Backend::typed_identifier ("macros", array_type, BUILTINS_LOCATION);
+
+  return Backend::struct_type ({length_field, macros_field});
 }
 
 // The entrypoint of a proc macro crate is a reference to the proc macro buffer
@@ -374,8 +380,15 @@ proc_macro_array (Context *ctx, tree proc_macro_buffer_type,
       index++;
     }
 
-  return Backend::array_constructor_expression (proc_macro_buffer_type, indexes,
-						ctors, BUILTINS_LOCATION);
+  auto length = build_int_cst (unsigned_type_node, ctors.size ());
+  auto array = Backend::array_constructor_expression (
+    build_array_type_nelts (proc_macro_type, ctors.size ()), indexes, ctors,
+    BUILTINS_LOCATION);
+  return Backend::constructor_expression (proc_macro_buffer_type,
+					  false /* invariant */,
+					  {length, array},
+					  -1 /* Structure: No index */,
+					  BUILTINS_LOCATION);
 }
 } // namespace init