Check for redefinition of globals and preserve static initialized variables (#81)

* Added check for redefinition of globals.

Since Cleanup may remove duplicated static functions or global
definitions we need to check for duplication during elaboration,
not just in C2C.
Bug 23410

* Do not eliminate unreferenced static variables with initializers

This way all initialized variables make it to the C2C pass,
where the initializers are checked for constant-ness.
Bug 23410

1 files changed, 15 insertions, 3 deletions

diff --git a/cparser/Cleanup.ml b/cparser/Cleanup.ml
index fe674d9b..75ee0e5a 100644
--- a/cparser/Cleanup.ml
+++ b/cparser/Cleanup.ml
@@ -118,11 +118,23 @@ let add_enum e =
     e
 
 (* Saturate the set of referenced identifiers, starting with externally
-   visible global declarations *)
+   visible global declarations.
+
+   Externally-visible globals include a minima:
+   - Definitions of functions, unless "static" or "inline".
+   - Declaration of variables with default storage.
+
+   We choose to also treat as visible and therefore to keep:
+   - "static" initialized variables, so that the checks on initializers
+     performed in C2C are performed on all initializers.
+     If the variable turns out to be unused, it will be removed
+     later by the Unusedglob pass.
+*)
 
 let visible_decl (sto, id, ty, init) =
-  sto = Storage_default &&
-  match ty with TFun _ -> false | _ -> true
+    init <> None ||
+    (sto = Storage_default &&
+     match ty with TFun _ -> false | _ -> true)
 
 let visible_fundef f =
   match f.fd_storage with