gdb: Convert language la_is_string_type_p field to a method

This commit changes the language_data::la_is_string_type_p function
pointer member variable into a member function of language_defn.

There should be no user visible changes after this commit.

gdb/ChangeLog:

	* ada-lang.c (ada_language_data): Delete la_is_string_type_p
	initializer.
	(ada_language::is_string_type_p): New member function.
	* c-lang.c (c_language_data): Delete la_is_string_type_p
	initializer.
	(cplus_language_data): Likewise.
	(asm_language_data): Likewise.
	(minimal_language_data): Likewise.
	* d-lang.c (d_language_data): Likewise.
	* f-lang.c (f_is_string_type_p): Delete function, implementation
	moved to f_language::is_string_type_p.
	(f_language_data): Delete la_is_string_type_p initializer.
	(f_language::is_string_type_p): New member function,
	implementation from f_is_string_type_p.
	* go-lang.c (go_is_string_type_p): Delete function, implementation
	moved to go_language::is_string_type_p.
	(go_language_data): Delete la_is_string_type_p initializer.
	(go_language::is_string_type_p): New member function,
	implementation from go_is_string_type_p.
	* language.c (language_defn::is_string_type_p): Define new member
	function.
	(default_is_string_type_p): Make static, add comment copied from
	header file.
	(unknown_language_data): Delete la_is_string_type_p initializer.
	(unknown_language::is_string_type_p): New member function.
	(auto_language_data): Delete la_is_string_type_p initializer.
	(auto_language::is_string_type_p): New member function.
	* language.h (language_data): Delete la_is_string_type_p field.
	(language_defn::is_string_type_p): Declare new function.
	(default_is_string_type_p): Delete desclaration, move comment to
	definition.
	* m2-lang.c (m2_is_string_type_p): Delete function, implementation
	moved to m2_language::is_string_type_p.
	(m2_language_data): Delete la_is_string_type_p initializer.
	(m2_language::is_string_type_p): New member function,
	implementation from m2_is_string_type_p.
	* objc-lang.c (objc_language_data): Delete la_is_string_type_p
	initializer.
	* opencl-lang.c (opencl_language_data): Likewise.
	* p-lang.c (pascal_is_string_type_p): Delete function,
	implementation moved to pascal_language::is_string_type_p.
	(pascal_language_data): Delete la_is_string_type_p initializer.
	(pascal_language::is_string_type_p): New member function,
	implementation from pascal_is_string_type_p.
	* rust-lang.c (rust_is_string_type_p): Delete function,
	implementation moved to rust_language::is_string_type_p.
	(rust_language_data): Delete la_is_string_type_p initializer.
	(rust_language::is_string_type_p): New member function,
	implementation from rust_is_string_type_p.
	* valprint.c (val_print_scalar_or_string_type_p): Update call to
	is_string_type_p.

gdb/language.c

@@ -690,6 +690,14 @@ language_defn::print_typedef (struct type *type, struct symbol *new_symbol,
   c_print_typedef (type, new_symbol, stream);
 }
 
+/* See language.h.  */
+
+bool
+language_defn::is_string_type_p (struct type *type) const
+{
+  return c_is_string_type_p (type);
+}
+
 /* The default implementation of the get_symbol_name_matcher_inner method
    from the language_defn class.  Matches with strncmp_iw.  */
 
@@ -741,9 +749,10 @@ language_defn::get_symbol_name_matcher_inner
   return default_symbol_name_matcher;
 }
 
-/* See language.h.  */
+/* Return true if TYPE is a string type, otherwise return false.  This
+   default implementation only detects TYPE_CODE_STRING.  */
 
-bool
+static bool
 default_is_string_type_p (struct type *type)
 {
   type = check_typedef (type);
@@ -789,7 +798,6 @@ extern const struct language_data unknown_language_data =
   1,				/* c-style arrays */
   0,				/* String lower bound */
   &default_varobj_ops,
-  default_is_string_type_p,
   "{...}"			/* la_struct_too_deep_ellipsis */
 };
 
@@ -884,6 +892,13 @@ public:
   {
     error (_("unimplemented unknown_language::print_typedef called"));
   }
+
+  /* See language.h.  */
+
+  bool is_string_type_p (struct type *type) const override
+  {
+    return default_is_string_type_p (type);
+  }
 };
 
 /* Single instance of the unknown language class.  */
@@ -909,7 +924,6 @@ extern const struct language_data auto_language_data =
   1,				/* c-style arrays */
   0,				/* String lower bound */
   &default_varobj_ops,
-  default_is_string_type_p,
   "{...}"			/* la_struct_too_deep_ellipsis */
 };
 
@@ -1004,6 +1018,13 @@ public:
   {
     error (_("unimplemented auto_language::print_typedef called"));
   }
+
+  /* See language.h.  */
+
+  bool is_string_type_p (struct type *type) const override
+  {
+    return default_is_string_type_p (type);
+  }
 };
 
 /* Single instance of the fake "auto" language.  */