Now all tinfos need code emitted have been chained into unemitted_tinfo_decls , then in finish_file at line 2628, emit_tinfo_decl determines whether the tinfo of decl needs be emitted, returns true if so. Below see that doing_runtime is set as 1 in emit_support_tinfos which is invoked at line 2571 in finish_file before.
Then at point invoking class_initializer (emit_tinfo_decl à get_pseudo_ti_init ), argument trail will be tree in below figure. Note that VAR_DECL of tinfo of base has been generated with initializers (desc is the corresponding VAR_DECL for tinfo of current class).
951 static tree
952 class_initializer (tree desc, tree target, tree trail) in rtti.c
953 {
954 tree init = tinfo_base_init (desc, target);
955
956 TREE_CHAIN (init) = trail;
957 init = build_constructor (NULL_TREE, init);
958 TREE_HAS_CONSTRUCTOR (init) = TREE_CONSTANT (init) = TREE_STATIC (init) = 1;
959 return init;
960 }
See that in class type_info, there is a “const char *” field name , block beginning at line 745 generates initializing code and the mangled name for this field.
738 static tree
739 tinfo_base_init (tree desc, tree target) in rtti.c
740 {
741 tree init = NULL_TREE;
742 tree name_decl;
743 tree vtable_ptr;
744
745 {
746 tree name_name;
747
748 /* Generate the NTBS array variable. */
749 tree name_type = build_cplus_array_type
750 (build_qualified_type (char_type_node, TYPE_QUAL_CONST),
751 NULL_TREE);
752 tree name_string = tinfo_name (target);
753
754 name_name = mangle_typeinfo_string_for_type (target);
755 name_decl = build_lang_decl (VAR_DECL, name_name, name_type);
756
757 DECL_ARTIFICIAL (name_decl) = 1;
758 TREE_READONLY (name_decl) = 1;
759 TREE_STATIC (name_decl) = 1;
760 DECL_EXTERNAL (name_decl) = 0;
761 TREE_PUBLIC (name_decl) = 1;
762 import_export_tinfo (name_decl, target, typeinfo_in_lib_p (target));
763 /* External name of the string containing the type's name has a
764 special name. */
765 SET_DECL_ASSEMBLER_NAME (name_decl,
766 mangle_typeinfo_string_for_type (target));
767 DECL_INITIAL (name_decl) = name_string;
768 mark_used (name_decl);
769 pushdecl_top_level_and_finish (name_decl, name_string);
770 }
771
772 vtable_ptr = TINFO_VTABLE_DECL (desc);
773 if (!vtable_ptr)
774 {
775 tree real_type;
776
777 push_nested_namespace (abi_node);
778 real_type = xref_tag (class_type, TINFO_REAL_NAME (desc),
779 true, false);
780 pop_nested_namespace (abi_node);
781
782 if (!COMPLETE_TYPE_P (real_type))
783 {
784 /* We never saw a definition of this type, so we need to
785 tell the compiler that this is an exported class, as
786 indeed all of the __*_type_info classes are. */
787 SET_CLASSTYPE_INTERFACE_KNOWN (real_type);
788 CLASSTYPE_INTERFACE_ONLY (real_type) = 1;
789 }
790
791 vtable_ptr = get_vtable_decl (real_type, /*complete=*/ 1);
792 vtable_ptr = build_unary_op (ADDR_EXPR, vtable_ptr, 0);
793
794 /* We need to point into the middle of the vtable. */
795 vtable_ptr = build
796 (PLUS_EXPR, TREE_TYPE (vtable_ptr), vtable_ptr,
797 size_binop (MULT_EXPR,
798 size_int (2 * TARGET_VTABLE_DATA_ENTRY_DISTANCE),
799 TYPE_SIZE_UNIT (vtable_entry_type )));
800 TREE_CONSTANT (vtable_ptr) = 1;
801
802 TINFO_VTABLE_DECL (desc) = vtable_ptr;
803 }
804
805 init = tree_cons (NULL_TREE, vtable_ptr, init);
806
807 init = tree_cons (NULL_TREE, decay_conversion (name_decl), init);
808
809 init = build_constructor (NULL_TREE, nreverse (init));
810 TREE_HAS_CONSTRUCTOR (init) = TREE_CONSTANT (init) = TREE_STATIC (init) = 1;
811 init = tree_cons (NULL_TREE, init, NULL_TREE);
812
813 return init;
814 }
Notice that above at line 791, the last argument of get_vtable_decl is 1, the function creates the VAR_DECL of vtable for this type of tinfo, and this VRA_DECL is marked as external, but within which cp_finish_decl does nothing.
Finally, var_init in emit_tinfo_decl at line 1452 is the following tree. And var_init will be used as initializer for this tinfo. And at line 1461 in emit_tinfo_decl , decl is the VAR_DECL of the tinfo, as we have seen in former section, cp_finish_decl has nothing to do.
If emit_tinfo_decl returns successfully, it means the intermediate tree has been changed, forces to iterate the DO WHILE loop again.
