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Diffstat (limited to 'share/gdb/python/gdb/frames.py')
-rw-r--r-- | share/gdb/python/gdb/frames.py | 228 |
1 files changed, 228 insertions, 0 deletions
diff --git a/share/gdb/python/gdb/frames.py b/share/gdb/python/gdb/frames.py new file mode 100644 index 0000000..19172e7 --- /dev/null +++ b/share/gdb/python/gdb/frames.py @@ -0,0 +1,228 @@ +# Frame-filter commands. +# Copyright (C) 2013-2014 Free Software Foundation, Inc. + +# 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/>. + +"""Internal functions for working with frame-filters.""" + +import gdb +from gdb.FrameIterator import FrameIterator +from gdb.FrameDecorator import FrameDecorator +import itertools +import collections + +def get_priority(filter_item): + """ Internal worker function to return the frame-filter's priority + from a frame filter object. This is a fail free function as it is + used in sorting and filtering. If a badly implemented frame + filter does not implement the priority attribute, return zero + (otherwise sorting/filtering will fail and prevent other frame + filters from executing). + + Arguments: + filter_item: An object conforming to the frame filter + interface. + + Returns: + The priority of the frame filter from the "priority" + attribute, or zero. + """ + # Do not fail here, as the sort will fail. If a filter has not + # (incorrectly) set a priority, set it to zero. + return getattr(filter_item, "priority", 0) + +def set_priority(filter_item, priority): + """ Internal worker function to set the frame-filter's priority. + + Arguments: + filter_item: An object conforming to the frame filter + interface. + priority: The priority to assign as an integer. + """ + + filter_item.priority = priority + +def get_enabled(filter_item): + """ Internal worker function to return a filter's enabled state + from a frame filter object. This is a fail free function as it is + used in sorting and filtering. If a badly implemented frame + filter does not implement the enabled attribute, return False + (otherwise sorting/filtering will fail and prevent other frame + filters from executing). + + Arguments: + filter_item: An object conforming to the frame filter + interface. + + Returns: + The enabled state of the frame filter from the "enabled" + attribute, or False. + """ + + # If the filter class is badly implemented when called from the + # Python filter command, do not cease filter operations, just set + # enabled to False. + return getattr(filter_item, "enabled", False) + +def set_enabled(filter_item, state): + """ Internal Worker function to set the frame-filter's enabled + state. + + Arguments: + filter_item: An object conforming to the frame filter + interface. + state: True or False, depending on desired state. + """ + + filter_item.enabled = state + +def return_list(name): + """ Internal Worker function to return the frame filter + dictionary, depending on the name supplied as an argument. If the + name is not "all", "global" or "progspace", it is assumed to name + an object-file. + + Arguments: + name: The name of the list, as specified by GDB user commands. + + Returns: + A dictionary object for a single specified dictionary, or a + list containing all the items for "all" + + Raises: + gdb.GdbError: A dictionary of that name cannot be found. + """ + + # If all dictionaries are wanted in the case of "all" we + # cannot return a combined dictionary as keys() may clash in + # between different dictionaries. As we just want all the frame + # filters to enable/disable them all, just return the combined + # items() as a chained iterator of dictionary values. + if name == "all": + glob = gdb.frame_filters.values() + prog = gdb.current_progspace().frame_filters.values() + return_iter = itertools.chain(glob, prog) + for objfile in gdb.objfiles(): + return_iter = itertools.chain(return_iter, objfile.frame_filters.values()) + + return return_iter + + if name == "global": + return gdb.frame_filters + else: + if name == "progspace": + cp = gdb.current_progspace() + return cp.frame_filters + else: + for objfile in gdb.objfiles(): + if name == objfile.filename: + return objfile.frame_filters + + msg = "Cannot find frame-filter dictionary for '" + name + "'" + raise gdb.GdbError(msg) + +def _sort_list(): + """ Internal Worker function to merge all known frame-filter + lists, prune any filters with the state set to "disabled", and + sort the list on the frame-filter's "priority" attribute. + + Returns: + sorted_list: A sorted, pruned list of frame filters to + execute. + """ + + all_filters = return_list("all") + sorted_frame_filters = sorted(all_filters, key = get_priority, + reverse = True) + + sorted_frame_filters = filter(get_enabled, + sorted_frame_filters) + + return sorted_frame_filters + +def execute_frame_filters(frame, frame_low, frame_high): + """ Internal function called from GDB that will execute the chain + of frame filters. Each filter is executed in priority order. + After the execution completes, slice the iterator to frame_low - + frame_high range. + + Arguments: + frame: The initial frame. + + frame_low: The low range of the slice. If this is a negative + integer then it indicates a backward slice (ie bt -4) which + counts backward from the last frame in the backtrace. + + frame_high: The high range of the slice. If this is -1 then + it indicates all frames until the end of the stack from + frame_low. + + Returns: + frame_iterator: The sliced iterator after all frame + filters have had a change to execute, or None if no frame + filters are registered. + """ + + # Get a sorted list of frame filters. + sorted_list = list(_sort_list()) + + # Check to see if there are any frame-filters. If not, just + # return None and let default backtrace printing occur. + if len(sorted_list) == 0: + return None + + frame_iterator = FrameIterator(frame) + + # Apply a basic frame decorator to all gdb.Frames. This unifies + # the interface. Python 3.x moved the itertools.imap + # functionality to map(), so check if it is available. + if hasattr(itertools,"imap"): + frame_iterator = itertools.imap(FrameDecorator, frame_iterator) + else: + frame_iterator = map(FrameDecorator, frame_iterator) + + for ff in sorted_list: + frame_iterator = ff.filter(frame_iterator) + + # Slicing + + # Is this a slice from the end of the backtrace, ie bt -2? + if frame_low < 0: + count = 0 + slice_length = abs(frame_low) + # We cannot use MAXLEN argument for deque as it is 2.6 onwards + # and some GDB versions might be < 2.6. + sliced = collections.deque() + + for frame_item in frame_iterator: + if count >= slice_length: + sliced.popleft(); + count = count + 1 + sliced.append(frame_item) + + return iter(sliced) + + # -1 for frame_high means until the end of the backtrace. Set to + # None if that is the case, to indicate to itertools.islice to + # slice to the end of the iterator. + if frame_high == -1: + frame_high = None + else: + # As frames start from 0, add one to frame_high so islice + # correctly finds the end + frame_high = frame_high + 1; + + sliced = itertools.islice(frame_iterator, frame_low, frame_high) + + return sliced |