Extension Language API

	* configure.ac (libpython checking): Remove all but python.o from
	CONFIG_OBS.  Remove all but python.c from CONFIG_SRCS.
	* configure: Regenerate.

	* Makefile.in (SFILES): Add extension.c.
	(HFILES_NO_SRCDIR): Add extension.h, extension-priv.h
	(COMMON_OBS): Add extension.o.
	* extension.h: New file.
	* extension-priv.h: New file.
	* extension.c: New file.

	* python/python-internal.h: #include "extension.h".
	(gdbpy_auto_load_enabled): Declare.
	(gdbpy_apply_val_pretty_printer): Declare.
	(gdbpy_apply_frame_filter): Declare.
	(gdbpy_preserve_values): Declare.
	(gdbpy_breakpoint_cond_says_stop): Declare.
	(gdbpy_breakpoint_has_cond): Declare.
	(void source_python_script_for_objfile): Delete.
	* python/python.c: #include "extension-priv.h".
	Delete inclusion of "observer.h".
	(extension_language_python): Moved here and renamed from
	script_language_python in py-auto-load.c.
	Redefined to be of type extension_language_defn.
	(python_extension_script_ops): New global.
	(python_extension_ops): New global.
	(struct python_env): New member previous_active.
	(restore_python_env): Call restore_active_ext_lang.
	(ensure_python_env): Call set_active_ext_lang.
	(gdbpy_clear_quit_flag): Renamed from clear_quit_flag, made static.
	New arg extlang.
	(gdbpy_set_quit_flag): Renamed from set_quit_flag, made static.
	New arg extlang.
	(gdbpy_check_quit_flag): Renamed from check_quit_flag, made static.
	New arg extlang.
	(gdbpy_eval_from_control_command): Renamed from
	eval_python_from_control_command, made static.  New arg extlang.
	(gdbpy_source_script) Renamed from source_python_script, made static.
	New arg extlang.
	(gdbpy_before_prompt_hook): Renamed from before_prompt_hook.  Change
	result to int.  New arg extlang.
	(gdbpy_source_objfile_script): Renamed from
	source_python_script_for_objfile, made static.  New arg extlang.
	(gdbpy_start_type_printers): Renamed from start_type_printers, made
	static.  New args extlang, extlang_printers.  Change result type to
	"void".
	(gdbpy_apply_type_printers): Renamed from apply_type_printers, made
	static.  New arg extlang.  Rename arg printers to extlang_printers
	and change type to ext_lang_type_printers *.
	(gdbpy_free_type_printers): Renamed from free_type_printers, made
	static.  Replace argument arg with extlang, extlang_printers.
	(!HAVE_PYTHON, eval_python_from_control_command): Delete.
	(!HAVE_PYTHON, source_python_script): Delete.
	(!HAVE_PYTHON, gdbpy_should_stop): Delete.
	(!HAVE_PYTHON, gdbpy_breakpoint_has_py_cond): Delete.
	(!HAVE_PYTHON, start_type_printers): Delete.
	(!HAVE_PYTHON, apply_type_printers): Delete.
	(!HAVE_PYTHON, free_type_printers): Delete.
	(_initialize_python): Delete call to observer_attach_before_prompt.
	(finalize_python): Set/restore active extension language.
	(gdbpy_finish_initialization) Renamed from
	finish_python_initialization, made static.  New arg extlang.
	(gdbpy_initialized): New function.
	* python/python.h: #include "extension.h".  Delete #include
	"value.h", "mi/mi-cmds.h".
	(extension_language_python): Declare.
	(GDBPY_AUTO_FILE_NAME): Delete.
	(enum py_bt_status): Moved to extension.h and renamed to
	ext_lang_bt_status.
	(enum frame_filter_flags): Moved to extension.h.
	(enum py_frame_args): Moved to extension.h and renamed to
	ext_lang_frame_args.
	(finish_python_initialization): Delete.
	(eval_python_from_control_command): Delete.
	(source_python_script): Delete.
	(apply_val_pretty_printer): Delete.
	(apply_frame_filter): Delete.
	(preserve_python_values): Delete.
	(gdbpy_script_language_defn): Delete.
	(gdbpy_should_stop, gdbpy_breakpoint_has_py_cond): Delete.
	(start_type_printers, apply_type_printers, free_type_printers): Delete.

	* auto-load.c: #include "extension.h".
	(GDB_AUTO_FILE_NAME): Delete.
	(auto_load_gdb_scripts_enabled): Make public.  New arg extlang.
	(script_language_gdb): Delete, moved to extension.c and renamed to
	extension_language_gdb.
	(source_gdb_script_for_objfile): Delete.
	(auto_load_pspace_info): New member unsupported_script_warning_printed.
	(loaded_script): Change type of language member to
	struct extension_language_defn *.
	(init_loaded_scripts_info): Initialize
	unsupported_script_warning_printed.
	(maybe_add_script): Make static.  Change type of language arg to
	struct extension_language_defn *.
	(clear_section_scripts): Reset unsupported_script_warning_printed.
	(auto_load_objfile_script_1): Rewrite to use extension language API.
	(auto_load_objfile_script): Make public.  Remove support-compiled-in
	and auto-load-enabled checks, moved to auto_load_scripts_for_objfile.
	(source_section_scripts): Rewrite to use extension language API.
	(load_auto_scripts_for_objfile): Rewrite to use
	auto_load_scripts_for_objfile.
	(collect_matching_scripts_data): Change type of language member to
	struct extension_language_defn *.
	(auto_load_info_scripts): Change type of language arg to
	struct extension_language_defn *.
	(unsupported_script_warning_print): New function.
	(script_not_found_warning_print): Make static.
	(_initialize_auto_load): Rewrite construction of scripts-directory
	help.
	* auto-load.h (struct objfile): Add forward decl.
	(struct script_language): Delete.
	(struct auto_load_pspace_info): Add forward decl.
	(struct extension_language_defn): Add forward decl.
	(maybe_add_script): Delete.
	(auto_load_objfile_script): Declare.
	(script_not_found_warning_print): Delete.
	(auto_load_info_scripts): Update prototype.
	(auto_load_gdb_scripts_enabled): Declare.
	* python/py-auto-load.c (gdbpy_auto_load_enabled): Renamed from
	auto_load_python_scripts_enabled and made public.
	(script_language_python): Delete, moved to python.c.
	(gdbpy_script_language_defn): Delete.
	(info_auto_load_python_scripts): Update to use
	extension_language_python.

	* breakpoint.c (condition_command): Replace call to
	gdbpy_breakpoint_has_py_cond with call to get_breakpoint_cond_ext_lang.
	(bpstat_check_breakpoint_conditions): Replace call to gdbpy_should_stop
	with call to breakpoint_ext_lang_cond_says_stop.
	* python/py-breakpoint.c (gdbpy_breakpoint_cond_says_stop): Renamed
	from gdbpy_should_stop.  Change result type to enum scr_bp_stop.
	New arg slang.  Return SCR_BP_STOP_UNSET if py_bp_object is NULL.
	(gdbpy_breakpoint_has_cond): Renamed from gdbpy_breakpoint_has_py_cond.
	New arg slang.
	(local_setattro): Print name of extension language with existing
	stop condition.

	* valprint.c (val_print, value_print): Update to call
	apply_ext_lang_val_pretty_printer.
	* cp-valprint.c (cp_print_value): Update call to
	apply_ext_lang_val_pretty_printer.
	* python/py-prettyprint.c: Remove #ifdef HAVE_PYTHON.
	(gdbpy_apply_val_pretty_printer): Renamed from
	apply_val_pretty_printer.  New arg extlang.
	(!HAVE_PYTHON, apply_val_pretty_printer): Delete.

	* cli/cli-cmds.c (source_script_from_stream): Rewrite to use
	extension language API.
	* cli/cli-script.c (execute_control_command): Update to call
	eval_ext_lang_from_control_command.

	* mi/mi-cmd-stack.c (mi_cmd_stack_list_frames): Update to use
	enum ext_lang_bt_status values.  Update call to
	apply_ext_lang_frame_filter.
	(mi_cmd_stack_list_locals): Ditto.
	(mi_cmd_stack_list_args): Ditto.
	(mi_cmd_stack_list_variables): Ditto.
	* mi/mi-main.c: Delete #include "python/python-internal.h".
	Add #include "extension.h".
	(mi_cmd_list_features): Replace reference to python internal variable
	gdb_python_initialized with call to ext_lang_initialized_p.

	* stack.c (backtrace_command_1): Update to use enum ext_lang_bt_status.
	Update to use enum ext_lang_frame_args.  Update to call
	apply_ext_lang_frame_filter.
	* python/py-framefilter.c (extract_sym): Update to use enum
	ext_lang_bt_status.
	(extract_value, py_print_type, py_print_value): Ditto.
	(py_print_single_arg, enumerate_args, enumerate_locals): Ditto.
	(py_mi_print_variables, py_print_locals, py_print_args): Ditto.
	(py_print_frame): Ditto.
	(gdbpy_apply_frame_filter): Renamed from apply_frame_filter.
	New arg extlang.  Update to use enum ext_lang_bt_status.

	* top.c (gdb_init): Delete #ifdef HAVE_PYTHON call to
	finish_python_initialization.  Replace with call to
	finish_ext_lang_initialization.

	* typeprint.c (do_free_global_table): Update to call
	free_ext_lang_type_printers.
	(create_global_typedef_table): Update to call
	start_ext_lang_type_printers.
	(find_global_typedef): Update to call apply_ext_lang_type_printers.
	* typeprint.h (struct ext_lang_type_printers): Add forward decl.
	(type_print_options): Change type of global_printers from "void *"
	to "struct ext_lang_type_printers *".

	* value.c (preserve_values): Update to call preserve_ext_lang_values.
	* python/py-value.c: Remove #ifdef HAVE_PYTHON.
	(gdbpy_preserve_values): Renamed from preserve_python_values.
	New arg extlang.
	(!HAVE_PYTHON, preserve_python_values): Delete.

	* utils.c (quit_flag): Delete, moved to extension.c.
	(clear_quit_flag, set_quit_flag, check_quit_flag): Delete, moved to
	extension.c.

	* eval.c: Delete #include "python/python.h".
	* main.c: Delete #include "python/python.h".

	* defs.h: Update comment.

	testsuite/

	* gdb.python/py-breakpoint.exp (test_bkpt_eval_funcs): Update expected
	output.

	* gdb.gdb/python-interrupts.exp: New file.

1 files changed, 285 insertions, 0 deletions

diff --git a/gdb/extension-priv.h b/gdb/extension-priv.h
new file mode 100644
index 00000000000..49ae6c32cae
--- /dev/null
+++ b/gdb/extension-priv.h
@@ -0,0 +1,285 @@
+/* Private implementation details of interface between gdb and its
+   extension languages.
+
+   Copyright (C) 2013 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#ifndef EXTENSION_PRIV_H
+#define EXTENSION_PRIV_H
+
+#include "extension.h"
+
+/* The return code for some API calls.  */
+
+enum ext_lang_rc
+  {
+    /* The operation completed successfully.  */
+    EXT_LANG_RC_OK,
+
+    /* The operation was not performed (e.g., no pretty-printer).  */
+    EXT_LANG_RC_NOP,
+
+    /* There was an error (e.g., Python error while printing a value).
+       When an error occurs no further extension languages are tried.
+       This is to preserve existing behaviour, and because it's convenient
+       for Python developers.
+       Note: This is different than encountering a memory error trying to read
+       a value for pretty-printing.  Here we're referring to, e.g., programming
+       errors that trigger an exception in the extension language.  */
+    EXT_LANG_RC_ERROR
+  };
+
+/* High level description of an extension/scripting language.
+   An entry for each is compiled into GDB regardless of whether the support
+   is present.  This is done so that we can issue meaningful errors if the
+   support is not compiled in.  */
+
+struct extension_language_defn
+{
+  /* Enum of the extension language.  */
+  enum extension_language language;
+
+  /* The name of the extension language, lowercase.  E.g., python.  */
+  const char *name;
+
+  /* The capitalized name of the extension language.
+     For python this is "Python".  For gdb this is "GDB".  */
+  const char *capitalized_name;
+
+  /* The file suffix of this extension language.  E.g., ".py".  */
+  const char *suffix;
+
+  /* The suffix of per-objfile scripts to auto-load.
+     E.g., When the program loads libfoo.so, look for libfoo.so-gdb.py.  */
+  const char *auto_load_suffix;
+
+  /* We support embedding external extension language code in GDB's own
+     scripting language.  We do this by having a special command that begins
+     the extension language snippet, and terminate it with "end".
+     This specifies the control type used to implement this.  */
+  enum command_control_type cli_control_type;
+
+  /* A pointer to the "methods" to load scripts in this language,
+     or NULL if the support is not compiled into GDB.  */
+  const struct extension_language_script_ops *script_ops;
+
+  /* Either a pointer to the "methods" of the extension language interface
+     or NULL if the support is not compiled into GDB.
+     This is also NULL for GDB's own scripting language which is relatively
+     primitive, and doesn't provide these features.  */
+  const struct extension_language_ops *ops;
+};
+
+/* The interface for loading scripts from external extension languages,
+   as well as GDB's own scripting language.
+   All of these methods are required to be implemented.  */
+
+struct extension_language_script_ops
+{
+  /* Load a script.  This is called, e.g., via the "source" command.
+     If there's an error while processing the script this function may,
+     but is not required to, throw an error.  */
+  script_sourcer_func *script_sourcer;
+
+  /* Load a script attached to an objfile.
+     If there's an error while processing the script this function may,
+     but is not required to, throw an error.  */
+  objfile_script_sourcer_func *objfile_script_sourcer;
+
+  /* Return non-zero if auto-loading scripts in this extension language
+     is enabled.  */
+  int (*auto_load_enabled) (const struct extension_language_defn *);
+};
+
+/* The interface for making calls from GDB to an external extension
+   language.  This is for non-script-loading related functionality, like
+   pretty-printing, etc.  The reason these are separated out is GDB's own
+   scripting language makes use of extension_language_script_opts, but it
+   makes no use of these.  There is no (current) intention to split
+   extension_language_ops up any further.
+   All of these methods are optional and may be NULL, except where
+   otherwise indicated.  */
+
+struct extension_language_ops
+{
+  /* Called at the end of gdb initialization to give the extension language
+     an opportunity to finish up.  This is useful for things like adding
+     new commands where one has to wait until gdb itself is initialized.  */
+  void (*finish_initialization) (const struct extension_language_defn *);
+
+  /* Return non-zero if the extension language successfully initialized.
+     This method is required.  */
+  int (*initialized) (const struct extension_language_defn *);
+
+  /* Process a sequence of commands embedded in GDB's own scripting language.
+     E.g.,
+     python
+     print 42
+     end  */
+  void (*eval_from_control_command) (const struct extension_language_defn *,
+				     struct command_line *);
+
+  /* Type-printing support:
+     start_type_printers, apply_type_printers, free_type_printers.
+     These methods are optional and may be NULL, but if one of them is
+     implemented then they all must be.  */
+
+  /* Called before printing a type.  */
+  void (*start_type_printers) (const struct extension_language_defn *,
+			       struct ext_lang_type_printers *);
+
+  /* Try to pretty-print TYPE.  If successful the pretty-printed type is
+     stored in *PRETTIED_TYPE, and the caller must free it.
+     Returns EXT_LANG_RC_OK upon success, EXT_LANG_RC_NOP if the type
+     is not recognized, and EXT_LANG_RC_ERROR if an error was encountered.
+     This function has a bit of a funny name, since it actually applies
+     recognizers, but this seemed clearer given the start_type_printers
+     and free_type_printers functions.  */
+  enum ext_lang_rc (*apply_type_printers)
+    (const struct extension_language_defn *,
+     const struct ext_lang_type_printers *,
+     struct type *, char **prettied_type);
+
+  /* Called after a type has been printed to give the type pretty-printer
+     mechanism an opportunity to clean up.  */
+  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 VALADDR
+     + 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.  VALADDR must point to
+     the head of VAL's contents buffer.
+     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, const gdb_byte *valaddr,
+     int embedded_offset, CORE_ADDR address,
+     struct ui_file *stream, int recurse,
+     const struct value *val, const struct value_print_options *options,
+     const struct language_defn *language);
+
+  /* GDB access to the "frame filter" feature.
+     FRAME is the source frame to start frame-filter invocation.  FLAGS is an
+     integer holding the flags for printing.  The following elements of
+     the FRAME_FILTER_FLAGS enum denotes the make-up of FLAGS:
+     PRINT_LEVEL is a flag indicating whether to print the frame's
+     relative level in the output.  PRINT_FRAME_INFO is a flag that
+     indicates whether this function should print the frame
+     information, PRINT_ARGS is a flag that indicates whether to print
+     frame arguments, and PRINT_LOCALS, likewise, with frame local
+     variables.  ARGS_TYPE is an enumerator describing the argument
+     format, OUT is the output stream to print.  FRAME_LOW is the
+     beginning of the slice of frames to print, and FRAME_HIGH is the
+     upper limit of the frames to count.  Returns SCR_BT_ERROR on error,
+     or SCR_BT_COMPLETED on success.  */
+  enum ext_lang_bt_status (*apply_frame_filter)
+    (const struct extension_language_defn *,
+     struct frame_info *frame, int flags, enum ext_lang_frame_args args_type,
+     struct ui_out *out, int frame_low, int frame_high);
+
+  /* Update values held by the extension language when OBJFILE is discarded.
+     New global types must be created for every such value, which must then be
+     updated to use the new types.
+     This function typically just iterates over all appropriate values and
+     calls preserve_one_value for each one.
+     COPIED_TYPES is used to prevent cycles / duplicates and is passed to
+     preserve_one_value.  */
+  void (*preserve_values) (const struct extension_language_defn *,
+			   struct objfile *objfile, htab_t copied_types);
+
+  /* Return non-zero if there is a stop condition for the breakpoint.
+     This is used to implement the restriction that a breakpoint may have
+     at most one condition.  */
+  int (*breakpoint_has_cond) (const struct extension_language_defn *,
+			      struct breakpoint *);
+
+  /* Return a value of enum ext_lang_bp_stop indicating if there is a stop
+     condition for the breakpoint, and if so whether the program should
+     stop.  This is called when the program has stopped at the specified
+     breakpoint.
+     While breakpoints can have at most one condition, this is called for
+     every extension language, even if another extension language has a
+     "stop" method: other kinds of breakpoints may be implemented using
+     this method, e.g., "finish breakpoints" in Python.  */
+  enum ext_lang_bp_stop (*breakpoint_cond_says_stop)
+    (const struct extension_language_defn *, struct breakpoint *);
+
+  /* The next three are used to connect GDB's SIGINT handling with the
+     extension language's.
+
+     Terminology: If an extension language can use GDB's SIGINT handling then
+     we say the extension language has "cooperative SIGINT handling".
+     Python is an example of this.
+
+     These need not be implemented, but if one of them is implemented
+     then they all must be.  */
+
+  /* Clear the SIGINT indicator.  */
+  void (*clear_quit_flag) (const struct extension_language_defn *);
+
+  /* Set the SIGINT indicator.
+     This is called by GDB's SIGINT handler and must be async-safe.  */
+  void (*set_quit_flag) (const struct extension_language_defn *);
+
+  /* Return non-zero if a SIGINT has occurred.
+     This is expected to also clear the indicator.  */
+  int (*check_quit_flag) (const struct extension_language_defn *);
+
+  /* Called before gdb prints its prompt, giving extension languages an
+     opportunity to change it with set_prompt.
+     Returns EXT_LANG_RC_OK if the prompt was changed, EXT_LANG_RC_NOP if
+     the prompt was not changed, and EXT_LANG_RC_ERROR if an error was
+     encountered.
+     Extension languages are called in order, and once the prompt is
+     changed or an error occurs no further languages are called.  */
+  enum ext_lang_rc (*before_prompt) (const struct extension_language_defn *,
+				     const char *current_gdb_prompt);
+};
+
+/* State necessary to restore a signal handler to its previous value.  */
+
+struct signal_handler
+{
+  /* Non-zero if "handler" has been set.  */
+  int handler_saved;
+
+  /* The signal handler.  */
+  RETSIGTYPE (*handler) ();
+};
+
+/* State necessary to restore the currently active extension language
+   to is previous value.  */
+
+struct active_ext_lang_state
+{
+  /* The previously active extension language.  */
+  const struct extension_language_defn *ext_lang;
+
+  /* Its SIGINT handler.  */
+  struct signal_handler sigint_handler;
+};
+
+extern const struct extension_language_defn *get_active_ext_lang (void);
+
+extern struct active_ext_lang_state *set_active_ext_lang
+  (const struct extension_language_defn *);
+
+extern void restore_active_ext_lang (struct active_ext_lang_state *previous);
+
+#endif /* EXTENSION_PRIV_H */