mirror of
https://sourceware.org/git/binutils-gdb.git
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272 lines
9.4 KiB
Python
272 lines
9.4 KiB
Python
# Copyright (C) 2015-2023 Free Software Foundation, Inc.
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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import gdb
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from gdb.unwinder import Unwinder, FrameId
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# These are set to test whether invalid register names cause an error.
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add_saved_register_errors = {}
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read_register_error = False
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class TestUnwinder(Unwinder):
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AMD64_RBP = 6
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AMD64_RSP = 7
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AMD64_RIP = None
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def __init__(self):
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Unwinder.__init__(self, "test unwinder")
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self.char_ptr_t = gdb.lookup_type("unsigned char").pointer()
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self.char_ptr_ptr_t = self.char_ptr_t.pointer()
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self._last_arch = None
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# Update the register descriptor AMD64_RIP based on ARCH.
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def _update_register_descriptors(self, arch):
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if self._last_arch != arch:
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TestUnwinder.AMD64_RIP = arch.registers().find("rip")
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self._last_arch = arch
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def _read_word(self, address):
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return address.cast(self.char_ptr_ptr_t).dereference()
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def __call__(self, pending_frame):
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"""Test unwinder written in Python.
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This unwinder can unwind the frames that have been deliberately
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corrupted in a specific way (functions in the accompanying
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py-unwind.c file do that.)
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This code is only on AMD64.
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On AMD64 $RBP points to the innermost frame (unless the code
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was compiled with -fomit-frame-pointer), which contains the
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address of the previous frame at offset 0. The functions
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deliberately corrupt their frames as follows:
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Before After
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Corruption: Corruption:
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+--------------+ +--------------+
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RBP-8 | | | Previous RBP |
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+--------------+ +--------------+
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RBP + Previous RBP | | RBP |
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+--------------+ +--------------+
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RBP+8 | Return RIP | | Return RIP |
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+--------------+ +--------------+
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Old SP | | | |
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This unwinder recognizes the corrupt frames by checking that
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*RBP == RBP, and restores previous RBP from the word above it.
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"""
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# Check that we can access the architecture of the pending
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# frame, and that this is the same architecture as for the
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# currently selected inferior.
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inf_arch = gdb.selected_inferior().architecture()
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frame_arch = pending_frame.architecture()
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if inf_arch != frame_arch:
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raise gdb.GdbError("architecture mismatch")
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self._update_register_descriptors(frame_arch)
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try:
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# NOTE: the registers in Unwinder API can be referenced
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# either by name or by number. The code below uses both
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# to achieve more coverage.
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bp = pending_frame.read_register("rbp").cast(self.char_ptr_t)
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if self._read_word(bp) != bp:
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return None
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# Found the frame that the test program has corrupted for us.
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# The correct BP for the outer frame has been saved one word
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# above, previous IP and SP are at the expected places.
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previous_bp = self._read_word(bp - 8)
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previous_ip = self._read_word(bp + 8)
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previous_sp = bp + 16
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try:
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pending_frame.read_register("nosuchregister")
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except ValueError as ve:
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global read_register_error
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read_register_error = str(ve)
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frame_id = FrameId(
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pending_frame.read_register(register=TestUnwinder.AMD64_RSP),
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pending_frame.read_register(TestUnwinder.AMD64_RIP),
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)
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unwind_info = pending_frame.create_unwind_info(frame_id)
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unwind_info.add_saved_register(TestUnwinder.AMD64_RBP, previous_bp)
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unwind_info.add_saved_register(value=previous_ip, register="rip")
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unwind_info.add_saved_register(register="rsp", value=previous_sp)
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global add_saved_register_errors
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try:
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unwind_info.add_saved_register("nosuchregister", previous_sp)
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except ValueError as ve:
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add_saved_register_errors["unknown_name"] = str(ve)
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try:
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unwind_info.add_saved_register(999, previous_sp)
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except ValueError as ve:
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add_saved_register_errors["unknown_number"] = str(ve)
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try:
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unwind_info.add_saved_register("rsp", 1234)
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except TypeError as ve:
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add_saved_register_errors["bad_value"] = str(ve)
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return unwind_info
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except (gdb.error, RuntimeError):
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return None
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global_test_unwinder = TestUnwinder()
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gdb.unwinder.register_unwinder(None, global_test_unwinder, True)
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# These are filled in by the simple_unwinder class.
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captured_pending_frame = None
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captured_pending_frame_repr = None
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captured_unwind_info = None
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captured_unwind_info_repr = None
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class simple_unwinder(Unwinder):
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def __init__(self, name, sp=0x123, pc=0x456):
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super().__init__(name)
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self._sp = sp
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self._pc = pc
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def __call__(self, pending_frame):
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global captured_pending_frame
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global captured_pending_frame_repr
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global captured_unwind_info
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global captured_unwind_info_repr
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assert pending_frame.is_valid()
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if captured_pending_frame is None:
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captured_pending_frame = pending_frame
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captured_pending_frame_repr = repr(pending_frame)
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fid = FrameId(self._sp, self._pc)
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uw = pending_frame.create_unwind_info(frame_id=fid)
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uw.add_saved_register("rip", gdb.Value(0x123))
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uw.add_saved_register("rbp", gdb.Value(0x456))
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uw.add_saved_register("rsp", gdb.Value(0x789))
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captured_unwind_info = uw
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captured_unwind_info_repr = repr(uw)
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return None
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# Return a dictionary of information about FRAME.
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def capture_frame_information(frame):
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name = frame.name()
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level = frame.level()
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language = frame.language()
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function = frame.function()
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architecture = frame.architecture()
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pc = frame.pc()
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sal = frame.find_sal()
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try:
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block = frame.block()
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assert isinstance(block, gdb.Block)
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except RuntimeError as rte:
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assert str(rte) == "Cannot locate block for frame."
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block = "RuntimeError: " + str(rte)
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return {
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"name": name,
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"level": level,
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"language": language,
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"function": function,
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"architecture": architecture,
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"pc": pc,
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"sal": sal,
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"block": block,
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}
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# List of information about each frame. The index into this list is
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# the frame level. This is populated by
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# capture_all_frame_information.
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all_frame_information = []
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# Fill in the global ALL_FRAME_INFORMATION list.
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def capture_all_frame_information():
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global all_frame_information
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all_frame_information = []
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gdb.newest_frame().select()
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frame = gdb.selected_frame()
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count = 0
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while frame is not None:
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frame.select()
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info = capture_frame_information(frame)
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level = info["level"]
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info["matched"] = False
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while len(all_frame_information) <= level:
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all_frame_information.append(None)
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assert all_frame_information[level] is None
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all_frame_information[level] = info
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if frame.name == "main" or count > 10:
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break
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count += 1
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frame = frame.older()
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# Assert that every entry in the global ALL_FRAME_INFORMATION list was
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# matched by the validating_unwinder.
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def check_all_frame_information_matched():
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global all_frame_information
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for entry in all_frame_information:
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assert entry["matched"]
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# An unwinder that doesn't match any frames. What it does do is
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# lookup information from the PendingFrame object and compare it
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# against information stored in the global ALL_FRAME_INFORMATION list.
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class validating_unwinder(Unwinder):
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def __init__(self):
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super().__init__("validating_unwinder")
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def __call__(self, pending_frame):
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info = capture_frame_information(pending_frame)
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level = info["level"]
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global all_frame_information
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old_info = all_frame_information[level]
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assert old_info is not None
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assert not old_info["matched"]
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for key, value in info.items():
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assert key in old_info, f"{key} not in old_info"
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assert type(value) == type(old_info[key])
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if isinstance(value, gdb.Block):
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assert value.start == old_info[key].start
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assert value.end == old_info[key].end
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assert value.is_static == old_info[key].is_static
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assert value.is_global == old_info[key].is_global
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else:
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assert str(value) == str(old_info[key])
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old_info["matched"] = True
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return None
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print("Python script imported")
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