Remove TYPE_TAG_NAME

TYPE_TAG_NAME has been an occasional source of confusion and bugs.  It
seems to me that it is only useful for C and C++ -- but even there,
not so much, because at least with DWARF there doesn't seem to be any
way to wind up with a type where the name and the tag name are both
non-NULL and different.

So, this patch removes TYPE_TAG_NAME entirely.  This should save a
little memory, but more importantly, it simplifies this part of gdb.

A few minor test suite adjustments were needed.  In some situations
the new code does not yield identical output to the old code.

gdb/ChangeLog
2018-06-01  Tom Tromey  <tom@tromey.com>

	* valops.c (enum_constant_from_type, value_namespace_elt)
	(value_maybe_namespace_elt): Update.
	* valarith.c (find_size_for_pointer_math): Update.
	* target-descriptions.c (make_gdb_type): Update.
	* symmisc.c (print_symbol): Update.
	* stabsread.c (define_symbol, read_type)
	(complain_about_struct_wipeout, add_undefined_type)
	(cleanup_undefined_types_1): Update.
	* rust-lang.c (rust_tuple_type_p, rust_slice_type_p)
	(rust_range_type_p, val_print_struct, rust_print_struct_def)
	(rust_internal_print_type, rust_composite_type)
	(rust_evaluate_funcall, rust_evaluate_subexp)
	(rust_inclusive_range_type_p): Update.
	* python/py-type.c (typy_get_tag): Update.
	* p-typeprint.c (pascal_type_print_base): Update.
	* mdebugread.c (parse_symbol, parse_type): Update.
	* m2-typeprint.c (m2_long_set, m2_record_fields, m2_enum):
	Update.
	* guile/scm-type.c (gdbscm_type_tag): Update.
	* go-lang.c (sixg_string_p): Update.
	* gnu-v3-abi.c (build_gdb_vtable_type, build_std_type_info_type):
	Update.
	* gdbtypes.h (struct main_type) <tag_name>: Remove.
	(TYPE_TAG_NAME): Remove.
	* gdbtypes.c (type_name_no_tag): Simplify.
	(check_typedef, check_types_equal, recursive_dump_type)
	(copy_type_recursive, arch_composite_type): Update.
	* f-typeprint.c (f_type_print_base): Update.  Print "Type" prefix
	in summary mode when needed.
	* eval.c (evaluate_funcall): Update.
	* dwarf2read.c (fixup_go_packaging, read_structure_type)
	(process_structure_scope, read_enumeration_type)
	(read_namespace_type, read_module_type, determine_prefix): Update.
	* cp-support.c (inspect_type): Update.
	* coffread.c (process_coff_symbol, decode_base_type): Update.
	* c-varobj.c (c_is_path_expr_parent): Update.
	* c-typeprint.c (c_type_print_base_struct_union): Update.
	(c_type_print_base_1): Update.  Print struct/class/union/enum in
	summary when using C language.
	* ax-gdb.c (gen_struct_ref, gen_namespace_elt)
	(gen_maybe_namespace_elt): Update.
	* ada-lang.c (ada_type_name): Simplify.
	(empty_record, ada_template_to_fixed_record_type_1)
	(template_to_static_fixed_type)
	(to_record_with_fixed_variant_part, ada_check_typedef): Update.

gdb/testsuite/ChangeLog
2018-06-01  Tom Tromey  <tom@tromey.com>

	* gdb.xml/tdesc-regs.exp (load_description): Update expected
	results.
	* gdb.dwarf2/method-ptr.exp: Set language to C++.
	* gdb.dwarf2/member-ptr-forwardref.exp: Set language to C++.
	* gdb.cp/typeid.exp (do_typeid_tests): Update type_re.
	* gdb.base/maint.exp (maint_pass_if): Update.

1 files changed, 5 insertions, 12 deletions

diff --git a/gdb/ada-lang.c b/gdb/ada-lang.c
index 64bddc26707..ceabf64c314 100644
--- a/gdb/ada-lang.c
+++ b/gdb/ada-lang.c
@@ -8111,18 +8111,15 @@ ada_prefer_type (struct type *type0, struct type *type1)
   return 0;
 }
 
-/* The name of TYPE, which is either its TYPE_NAME, or, if that is
-   null, its TYPE_TAG_NAME.  Null if TYPE is null.  */
+/* The name of TYPE, which is its TYPE_NAME.  Null if TYPE is
+   null.  */
 
 const char *
 ada_type_name (struct type *type)
 {
   if (type == NULL)
     return NULL;
-  else if (TYPE_NAME (type) != NULL)
-    return TYPE_NAME (type);
-  else
-    return TYPE_TAG_NAME (type);
+  return TYPE_NAME (type);
 }
 
 /* Search the list of "descriptive" types associated to TYPE for a type
@@ -8291,7 +8288,6 @@ empty_record (struct type *templ)
   TYPE_FIELDS (type) = NULL;
   INIT_CPLUS_SPECIFIC (type);
   TYPE_NAME (type) = "<empty>";
-  TYPE_TAG_NAME (type) = NULL;
   TYPE_LENGTH (type) = 0;
   return type;
 }
@@ -8350,7 +8346,6 @@ ada_template_to_fixed_record_type_1 (struct type *type,
     TYPE_ALLOC (rtype, nfields * sizeof (struct field));
   memset (TYPE_FIELDS (rtype), 0, sizeof (struct field) * nfields);
   TYPE_NAME (rtype) = ada_type_name (type);
-  TYPE_TAG_NAME (rtype) = NULL;
   TYPE_FIXED_INSTANCE (rtype) = 1;
 
   off = 0;
@@ -8627,7 +8622,6 @@ template_to_static_fixed_type (struct type *type0)
 	      memcpy (TYPE_FIELDS (type), TYPE_FIELDS (type0),
 		      sizeof (struct field) * nfields);
 	      TYPE_NAME (type) = ada_type_name (type0);
-	      TYPE_TAG_NAME (type) = NULL;
 	      TYPE_FIXED_INSTANCE (type) = 1;
 	      TYPE_LENGTH (type) = 0;
 	    }
@@ -8677,7 +8671,6 @@ to_record_with_fixed_variant_part (struct type *type, const gdb_byte *valaddr,
   memcpy (TYPE_FIELDS (rtype), TYPE_FIELDS (type),
           sizeof (struct field) * nfields);
   TYPE_NAME (rtype) = ada_type_name (type);
-  TYPE_TAG_NAME (rtype) = NULL;
   TYPE_FIXED_INSTANCE (rtype) = 1;
   TYPE_LENGTH (rtype) = TYPE_LENGTH (type);
 
@@ -9288,11 +9281,11 @@ ada_check_typedef (struct type *type)
   type = check_typedef (type);
   if (type == NULL || TYPE_CODE (type) != TYPE_CODE_ENUM
       || !TYPE_STUB (type)
-      || TYPE_TAG_NAME (type) == NULL)
+      || TYPE_NAME (type) == NULL)
     return type;
   else
     {
-      const char *name = TYPE_TAG_NAME (type);
+      const char *name = TYPE_NAME (type);
       struct type *type1 = ada_find_any_type (name);
 
       if (type1 == NULL)