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      1 # Copyright (C) 2021-2024 Free Software Foundation, Inc.
      2 
      3 # This program is free software; you can redistribute it and/or modify
      4 # it under the terms of the GNU General Public License as published by
      5 # the Free Software Foundation; either version 3 of the License, or
      6 # (at your option) any later version.
      7 #
      8 # This program is distributed in the hope that it will be useful,
      9 # but WITHOUT ANY WARRANTY; without even the implied warranty of
     10 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     11 # GNU General Public License for more details.
     12 #
     13 # You should have received a copy of the GNU General Public License
     14 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
     15 
     16 import gdb
     17 from gdb.unwinder import Unwinder
     18 
     19 
     20 class FrameId(object):
     21     def __init__(self, sp, pc):
     22         self._sp = sp
     23         self._pc = pc
     24 
     25     @property
     26     def sp(self):
     27         return self._sp
     28 
     29     @property
     30     def pc(self):
     31         return self._pc
     32 
     33 
     34 class TestUnwinder(Unwinder):
     35     def __init__(self, use_descriptors):
     36         if use_descriptors:
     37             tag = "using descriptors"
     38         else:
     39             tag = "using strings"
     40 
     41         Unwinder.__init__(self, "break unwinding %s" % tag)
     42         self._use_descriptors = use_descriptors
     43 
     44     def __call__(self, pending_frame):
     45         pc_desc = pending_frame.architecture().registers().find("pc")
     46         pc = pending_frame.read_register(pc_desc)
     47 
     48         sp_desc = pending_frame.architecture().registers().find("sp")
     49         sp = pending_frame.read_register(sp_desc)
     50 
     51         block = gdb.block_for_pc(int(pc))
     52         if block is None:
     53             return None
     54         func = block.function
     55         if func is None:
     56             return None
     57         if str(func) != "bar":
     58             return None
     59 
     60         fid = FrameId(pc, sp)
     61         unwinder = pending_frame.create_unwind_info(fid)
     62         if self._use_descriptors:
     63             unwinder.add_saved_register(pc_desc, pc)
     64             unwinder.add_saved_register(sp_desc, sp)
     65         else:
     66             unwinder.add_saved_register("pc", pc)
     67             unwinder.add_saved_register("sp", sp)
     68         return unwinder
     69 
     70 
     71 gdb.unwinder.register_unwinder(None, TestUnwinder(True), True)
     72 gdb.unwinder.register_unwinder(None, TestUnwinder(False), True)
     73