There is a single call to unshare_expr in gigi and it is actually superfluous if you do things properly.
Tested on i586-suse-linux, applied on the mainline. 2012-03-07 Eric Botcazou <ebotca...@adacore.com> * gcc-interface/trans.c (Identifier_to_gnu): Don't unshare initializer. (add_decl_expr): Mark external DECLs as used. * gcc-interface/utils.c (convert) <CONSTRUCTOR>: Copy the vector. -- Eric Botcazou
Index: gcc-interface/utils.c =================================================================== --- gcc-interface/utils.c (revision 184852) +++ gcc-interface/utils.c (working copy) @@ -3894,6 +3894,8 @@ convert (tree type, tree expr) { expr = copy_node (expr); TREE_TYPE (expr) = type; + CONSTRUCTOR_ELTS (expr) + = VEC_copy (constructor_elt, gc, CONSTRUCTOR_ELTS (expr)); return expr; } Index: gcc-interface/trans.c =================================================================== --- gcc-interface/trans.c (revision 184852) +++ gcc-interface/trans.c (working copy) @@ -1102,11 +1102,9 @@ Identifier_to_gnu (Node_Id gnat_node, tr = lvalue_required_p (gnat_node, gnu_result_type, true, address_of_constant, Is_Aliased (gnat_temp)); - /* ??? We need to unshare the initializer if the object is external - as such objects are not marked for unsharing if we are not at the - global level. This should be fixed in add_decl_expr. */ + /* Finally retrieve the initializer if this is deemed valid. */ if ((constant_only && !address_of_constant) || !require_lvalue) - gnu_result = unshare_expr (DECL_INITIAL (gnu_result)); + gnu_result = DECL_INITIAL (gnu_result); } /* The GNAT tree has the type of a function set to its result type, so we @@ -7113,10 +7111,10 @@ add_decl_expr (tree gnu_decl, Entity_Id gnu_stmt = build1 (DECL_EXPR, void_type_node, gnu_decl); - /* If we are global, we don't want to actually output the DECL_EXPR for - this decl since we already have evaluated the expressions in the + /* If we are external or global, we don't want to output the DECL_EXPR for + this DECL node since we already have evaluated the expressions in the sizes and positions as globals and doing it again would be wrong. */ - if (global_bindings_p ()) + if (DECL_EXTERNAL (gnu_decl) || global_bindings_p ()) { /* Mark everything as used to prevent node sharing with subprograms. Note that walk_tree knows how to deal with TYPE_DECL, but neither @@ -7135,7 +7133,7 @@ add_decl_expr (tree gnu_decl, Entity_Id && !TYPE_FAT_POINTER_P (type)) MARK_VISITED (TYPE_ADA_SIZE (type)); } - else if (!DECL_EXTERNAL (gnu_decl)) + else add_stmt_with_node (gnu_stmt, gnat_entity); /* If this is a variable and an initializer is attached to it, it must be