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, 10 insertions, 22 deletions

diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index 14cae6e..b8e681b 100644
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -9762,8 +9762,6 @@ fixup_go_packaging (struct dwarf2_cu *cu)
 				     saved_package_name);
       struct symbol *sym;
 
-      TYPE_TAG_NAME (type) = TYPE_NAME (type);
-
       sym = allocate_symbol (objfile);
       SYMBOL_SET_LANGUAGE (sym, language_go, &objfile->objfile_obstack);
       SYMBOL_SET_NAMES (sym, saved_package_name,
@@ -15653,18 +15651,13 @@ read_structure_type (struct die_info *die, struct dwarf2_cu *cu)
 	  if (get_die_type (die, cu) != NULL)
 	    return get_die_type (die, cu);
 
-	  TYPE_TAG_NAME (type) = full_name;
-	  if (die->tag == DW_TAG_structure_type
-	      || die->tag == DW_TAG_class_type)
-	    TYPE_NAME (type) = TYPE_TAG_NAME (type);
+	  TYPE_NAME (type) = full_name;
 	}
       else
 	{
 	  /* The name is already allocated along with this objfile, so
 	     we don't need to duplicate it for the type.  */
-	  TYPE_TAG_NAME (type) = name;
-	  if (die->tag == DW_TAG_class_type)
-	    TYPE_NAME (type) = TYPE_TAG_NAME (type);
+	  TYPE_NAME (type) = name;
 	}
     }
 
@@ -15944,8 +15937,7 @@ process_structure_scope (struct die_info *die, struct dwarf2_cu *cu)
 		  if (i < TYPE_N_BASECLASSES (t))
 		    complaint (_("virtual function table pointer "
 				 "not found when defining class '%s'"),
-			       TYPE_TAG_NAME (type) ? TYPE_TAG_NAME (type) :
-			       "");
+			       TYPE_NAME (type) ? TYPE_NAME (type) : "");
 		}
 	      else
 		{
@@ -16135,7 +16127,7 @@ read_enumeration_type (struct die_info *die, struct dwarf2_cu *cu)
   TYPE_CODE (type) = TYPE_CODE_ENUM;
   name = dwarf2_full_name (NULL, die, cu);
   if (name != NULL)
-    TYPE_TAG_NAME (type) = name;
+    TYPE_NAME (type) = name;
 
   attr = dwarf2_attr (die, DW_AT_type, cu);
   if (attr != NULL)
@@ -16686,7 +16678,6 @@ read_namespace_type (struct die_info *die, struct dwarf2_cu *cu)
 
   /* Create the type.  */
   type = init_type (objfile, TYPE_CODE_NAMESPACE, 0, name);
-  TYPE_TAG_NAME (type) = TYPE_NAME (type);
 
   return set_die_type (die, type, cu);
 }
@@ -16751,9 +16742,6 @@ read_module_type (struct die_info *die, struct dwarf2_cu *cu)
                sect_offset_str (die->sect_off));
   type = init_type (objfile, TYPE_CODE_MODULE, 0, module_name);
 
-  /* determine_prefix uses TYPE_TAG_NAME.  */
-  TYPE_TAG_NAME (type) = TYPE_NAME (type);
-
   return set_die_type (die, type, cu);
 }
 
@@ -22183,18 +22171,18 @@ determine_prefix (struct die_info *die, struct dwarf2_cu *cu)
 	   DW_TAG_namespace DIEs with a name of "::" for the global namespace.
 	   Work around this problem here.  */
 	if (cu->language == language_cplus
-	    && strcmp (TYPE_TAG_NAME (parent_type), "::") == 0)
+	    && strcmp (TYPE_NAME (parent_type), "::") == 0)
 	  return "";
 	/* We give a name to even anonymous namespaces.  */
-	return TYPE_TAG_NAME (parent_type);
+	return TYPE_NAME (parent_type);
       case DW_TAG_class_type:
       case DW_TAG_interface_type:
       case DW_TAG_structure_type:
       case DW_TAG_union_type:
       case DW_TAG_module:
 	parent_type = read_type_die (parent, cu);
-	if (TYPE_TAG_NAME (parent_type) != NULL)
-	  return TYPE_TAG_NAME (parent_type);
+	if (TYPE_NAME (parent_type) != NULL)
+	  return TYPE_NAME (parent_type);
 	else
 	  /* An anonymous structure is only allowed non-static data
 	     members; no typedefs, no member functions, et cetera.
@@ -22219,8 +22207,8 @@ determine_prefix (struct die_info *die, struct dwarf2_cu *cu)
 	parent_type = read_type_die (parent, cu);
 	if (TYPE_DECLARED_CLASS (parent_type))
 	  {
-	    if (TYPE_TAG_NAME (parent_type) != NULL)
-	      return TYPE_TAG_NAME (parent_type);
+	    if (TYPE_NAME (parent_type) != NULL)
+	      return TYPE_NAME (parent_type);
 	    return "";
 	  }
 	/* Fall through.  */