Change extension language pretty-printers to use value API

This changes the extension language pretty-printers to use the value
API.

Note that new functions were needed, for both Guile and Python.
Currently both languages always wrap values by removing the values
from the value chain.  This makes sense to avoid strange behavior with
watchpoints, and to avoid excessive memory use.  However, when
printing, it's important to leave the passed-in value untouched, in
case pretty-printing does nothing -- that way the caller can still
access it.

gdb/ChangeLog
2020-03-13  Tom Tromey  <tom@tromey.com>

	* valprint.c (do_val_print): Update.
	* python/python-internal.h (gdbpy_apply_val_pretty_printer): Take
	a struct value.
	(value_to_value_object_no_release): Declare.
	* python/py-value.c (value_to_value_object_no_release): New
	function.
	* python/py-prettyprint.c (gdbpy_apply_val_pretty_printer): Take a
	struct value.
	* guile/scm-value.c (vlscm_scm_from_value_no_release): New
	function.
	* guile/scm-pretty-print.c (gdbscm_apply_val_pretty_printer): Take
	a struct value.
	* guile/guile-internal.h (vlscm_scm_from_value_no_release):
	Declare.
	(gdbscm_apply_val_pretty_printer): Take a struct value.
	* extension.h (apply_ext_lang_val_pretty_printer): Take a struct
	value.
	* extension.c (apply_ext_lang_val_pretty_printer): Take a struct
	value.
	* extension-priv.h (struct extension_language_ops)
	<apply_val_pretty_printer>: Take a struct value.
	* cp-valprint.c (cp_print_value): Create a struct value.
	(cp_print_value): Update.

1 files changed, 6 insertions, 11 deletions

diff --git a/gdb/extension-priv.h b/gdb/extension-priv.h
index c356710..8596e0a 100644
--- a/gdb/extension-priv.h
+++ b/gdb/extension-priv.h
@@ -152,19 +152,14 @@ struct extension_language_ops
   void (*free_type_printers) (const struct extension_language_defn *,
 			      struct ext_lang_type_printers *);
 
-  /* Try to pretty-print a value of type TYPE located at VAL's contents
-     buffer + EMBEDDED_OFFSET, which came from the inferior at address
-     ADDRESS + EMBEDDED_OFFSET, onto stdio stream STREAM according to
-     OPTIONS.
-     VAL is the whole object that came from ADDRESS.
-     Returns EXT_LANG_RC_OK upon success, EXT_LANG_RC_NOP if the value
-     is not recognized, and EXT_LANG_RC_ERROR if an error was encountered.  */
+  /* Try to pretty-print a value, onto stdio stream STREAM according
+     to OPTIONS.  VAL is the object to print.  Returns EXT_LANG_RC_OK
+     upon success, EXT_LANG_RC_NOP if the value is not recognized, and
+     EXT_LANG_RC_ERROR if an error was encountered.  */
   enum ext_lang_rc (*apply_val_pretty_printer)
     (const struct extension_language_defn *,
-     struct type *type,
-     LONGEST embedded_offset, CORE_ADDR address,
-     struct ui_file *stream, int recurse,
-     struct value *val, const struct value_print_options *options,
+     struct value *val, struct ui_file *stream, int recurse,
+     const struct value_print_options *options,
      const struct language_defn *language);
 
   /* GDB access to the "frame filter" feature.