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, 33 insertions, 15 deletions

diff --git a/gdb/c-typeprint.c b/gdb/c-typeprint.c
index 97f7aaa..6141950 100644
--- a/gdb/c-typeprint.c
+++ b/gdb/c-typeprint.c
@@ -1189,13 +1189,13 @@ c_type_print_base_struct_union (struct type *type, struct ui_file *stream,
      spurious "{unnamed struct}"/"{unnamed union}"/"{unnamed
      enum}" tag for unnamed struct/union/enum's, which we don't
      want to print.  */
-  if (TYPE_TAG_NAME (type) != NULL
-      && !startswith (TYPE_TAG_NAME (type), "{unnamed"))
+  if (TYPE_NAME (type) != NULL
+      && !startswith (TYPE_NAME (type), "{unnamed"))
     {
       /* When printing the tag name, we are still effectively
 	 printing in the outer context, hence the use of FLAGS
 	 here.  */
-      print_name_maybe_canonical (TYPE_TAG_NAME (type), flags, stream);
+      print_name_maybe_canonical (TYPE_NAME (type), flags, stream);
       if (show > 0)
 	fputs_filtered (" ", stream);
     }
@@ -1204,10 +1204,10 @@ c_type_print_base_struct_union (struct type *type, struct ui_file *stream,
     {
       /* If we just printed a tag name, no need to print anything
 	 else.  */
-      if (TYPE_TAG_NAME (type) == NULL)
+      if (TYPE_NAME (type) == NULL)
 	fprintf_filtered (stream, "{...}");
     }
-  else if (show > 0 || TYPE_TAG_NAME (type) == NULL)
+  else if (show > 0 || TYPE_NAME (type) == NULL)
     {
       struct type *basetype;
       int vptr_fieldno;
@@ -1620,15 +1620,33 @@ c_type_print_base_1 (struct type *type, struct ui_file *stream,
 
   /* When SHOW is zero or less, and there is a valid type name, then
      always just print the type name directly from the type.  */
-  /* If we have "typedef struct foo {. . .} bar;" do we want to print
-     it as "struct foo" or as "bar"?  Pick the latter, because C++
-     folk tend to expect things like "class5 *foo" rather than "struct
-     class5 *foo".  */
 
   if (show <= 0
       && TYPE_NAME (type) != NULL)
     {
       c_type_print_modifier (type, stream, 0, 1);
+
+      /* If we have "typedef struct foo {. . .} bar;" do we want to
+	 print it as "struct foo" or as "bar"?  Pick the latter for
+	 C++, because C++ folk tend to expect things like "class5
+	 *foo" rather than "struct class5 *foo".  We rather
+	 arbitrarily choose to make language_minimal work in a C-like
+	 way. */
+      if (language == language_c || language == language_minimal)
+	{
+	  if (TYPE_CODE (type) == TYPE_CODE_UNION)
+	    fprintf_filtered (stream, "union ");
+	  else if (TYPE_CODE (type) == TYPE_CODE_STRUCT)
+	    {
+	      if (TYPE_DECLARED_CLASS (type))
+		fprintf_filtered (stream, "class ");
+	      else
+		fprintf_filtered (stream, "struct ");
+	    }
+	  else if (TYPE_CODE (type) == TYPE_CODE_ENUM)
+	    fprintf_filtered (stream, "enum ");
+	}
+
       print_name_maybe_canonical (TYPE_NAME (type), flags, stream);
       return;
     }
@@ -1679,10 +1697,10 @@ c_type_print_base_1 (struct type *type, struct ui_file *stream,
          "{unnamed struct}"/"{unnamed union}"/"{unnamed enum}"
          tag for unnamed struct/union/enum's, which we don't
          want to print.  */
-      if (TYPE_TAG_NAME (type) != NULL
-	  && !startswith (TYPE_TAG_NAME (type), "{unnamed"))
+      if (TYPE_NAME (type) != NULL
+	  && !startswith (TYPE_NAME (type), "{unnamed"))
 	{
-	  print_name_maybe_canonical (TYPE_TAG_NAME (type), flags, stream);
+	  print_name_maybe_canonical (TYPE_NAME (type), flags, stream);
 	  if (show > 0)
 	    fputs_filtered (" ", stream);
 	}
@@ -1692,10 +1710,10 @@ c_type_print_base_1 (struct type *type, struct ui_file *stream,
 	{
 	  /* If we just printed a tag name, no need to print anything
 	     else.  */
-	  if (TYPE_TAG_NAME (type) == NULL)
+	  if (TYPE_NAME (type) == NULL)
 	    fprintf_filtered (stream, "{...}");
 	}
-      else if (show > 0 || TYPE_TAG_NAME (type) == NULL)
+      else if (show > 0 || TYPE_NAME (type) == NULL)
 	{
 	  LONGEST lastval = 0;
 
@@ -1804,7 +1822,7 @@ c_type_print_base_1 (struct type *type, struct ui_file *stream,
 
     case TYPE_CODE_NAMESPACE:
       fputs_filtered ("namespace ", stream);
-      fputs_filtered (TYPE_TAG_NAME (type), stream);
+      fputs_filtered (TYPE_NAME (type), stream);
       break;
 
     default: