binutils-gdb/gdb/extension-priv.h

286 lines
12 KiB
C

/* Private implementation details of interface between gdb and its
extension languages.
Copyright (C) 2014 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 */