forked from Imagelibrary/binutils-gdb
8e2ae00bb4
I've been reviewing all uses of PyObject_IsInstance, and I believe
that the use of PyObject_IsInstance in py-unwind.c is not entirely
correct. The use of PyObject_IsInstance is in this code in
frame_unwind_python::sniff:
if (PyObject_IsInstance (pyo_unwind_info,
(PyObject *) &unwind_info_object_type) <= 0)
error (_("A Unwinder should return gdb.UnwindInfo instance."));
The problem is that PyObject_IsInstance can return -1 to indicate an
error, in which case a Python error will have been set. Now, the
above code appears to handle this case, it checks for '<= 0', however,
frame_unwind_python::sniff has this near the start:
gdbpy_enter enter_py (gdbarch);
And looking in python.c at 'gdbpy_enter::~gdbpy_enter ()', you'll
notice that if an error is set then the error is printed, but also, we
get a warning about an unhandled Python exception. Clearly, all
exceptions should have been handled by the time the gdbpy_enter
destructor is called.
I've added a test as part of this commit that exposes this problem,
the current output is:
(gdb) backtrace
Python Exception <class 'RuntimeError'>: error in Blah.__class__
warning: internal error: Unhandled Python exception
Python Exception <class 'gdb.error'>: A Unwinder should return gdb.UnwindInfo instance.
#0 corrupt_frame_inner () at /home/andrew/projects/binutils-gdb/build.dev-g/gdb/testsuite/../../../src.dev-g/gdb/test>
(gdb)
An additional observation is that we use PyObject_IsInstance to check
that the return value is a gdb.UnwindInfo, or a sub-class. However,
gdb.UnwindInfo lacks the Py_TPFLAGS_BASETYPE flag, and so cannot be
sub-classed. As such, PyObject_IsInstance is not really needed, we
could use PyObject_TypeCheck instead. The PyObject_TypeCheck function
only returns 0 or 1, there is no -1 error case. Switching to
PyObject_TypeCheck then, fixes the above problem.
There's a new test that exposes the problems that originally existed.
Approved-By: Tom Tromey <tom@tromey.com>
283 lines
11 KiB
Plaintext
283 lines
11 KiB
Plaintext
# Copyright (C) 2015-2025 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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# This file is part of the GDB testsuite. It verifies that frame
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# unwinders can be implemented in Python.
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load_lib gdb-python.exp
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require allow_python_tests
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standard_testfile
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# Stack protection can make the stack look a bit different, breaking the
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# assumptions this test has about its layout.
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set flags "additional_flags=-fno-stack-protector"
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if { [prepare_for_testing "failed to prepare" ${testfile} ${srcfile} "debug $flags"] } {
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return -1
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}
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# This test runs on a specific platform.
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require is_x86_64_m64_target
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# The following tests require execution.
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if {![runto_main]} {
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return 0
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}
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# Check for the corrupt backtrace.
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proc check_for_broken_backtrace {testname} {
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gdb_test_sequence "where" $testname {
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"\\r\\n#0 .* corrupt_frame_inner \\(\\) at "
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"\\r\\n#1 .* corrupt_frame_outer \\(\\) at "
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"Backtrace stopped: frame did not save the PC"
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}
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}
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# Check for the correct backtrace.
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proc check_for_fixed_backtrace {testname} {
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gdb_test_sequence "where" $testname {
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"\\r\\n#0 .* corrupt_frame_inner \\(\\) at "
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"\\r\\n#1 .* corrupt_frame_outer \\(\\) at "
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"\\r\\n#2 .* main \\(.*\\) at"
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}
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}
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# Check the 'info unwinder' output.
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proc check_info_unwinder {testname enabled} {
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if {$enabled} {
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set suffix ""
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} else {
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set suffix " \\\[disabled\\\]"
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}
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gdb_test_sequence "info unwinder" $testname \
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[list \
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"Global:" \
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" test unwinder${suffix}"]
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}
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set pyfile [gdb_remote_download host ${srcdir}/${subdir}/${testfile}.py]
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gdb_breakpoint [gdb_get_line_number "break backtrace-broken"]
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gdb_continue_to_breakpoint "break backtrace-broken"
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check_for_broken_backtrace "Backtrace is initially broken"
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gdb_test "source ${pyfile}" "Python script imported" \
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"import python scripts"
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check_info_unwinder "info unwinder after loading script" on
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check_for_fixed_backtrace "check backtrace after loading unwinder"
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# Check that the Python unwinder frames can be flushed / released.
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gdb_test "maint flush register-cache" "Register cache flushed\\." "flush frames"
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check_for_fixed_backtrace "check backtrace after flush"
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# Try to disable the unwinder but instead set the enabled field to a
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# non boolean value. This should fail. Check the 'info unwinder'
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# output to be sure.
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gdb_test "python global_test_unwinder.enabled = \"off\"" \
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[multi_line \
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"TypeError.*: incorrect type for enabled attribute: <class 'str'>" \
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"Error occurred in Python.*"]
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check_info_unwinder "info unwinder after failed disable" on
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# While we're doing silly stuff, lets try to change the name of this
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# unwider. Doing this is bad as the new name might clash with an
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# already registered name, which violates the promises made during
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# 'register_unwinder'.
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set pattern_1 "can't set attribute(?: 'name')?"
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set pattern_2 "property 'name' of 'TestUnwinder' object has no setter"
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gdb_test "python global_test_unwinder.name = \"foo\"" \
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[multi_line \
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"AttributeError.*: (?:${pattern_1}|${pattern_2})" \
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"Error occurred in Python.*"]
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check_info_unwinder "info unwinder after failed name change" on
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# Now actually disable the unwinder by manually adjusting the
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# 'enabled' attribute. Check that the stack is once again broken, and
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# that the unwinder shows as disabled in the 'info unwinder' output.
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gdb_test_no_output "python global_test_unwinder.enabled = False"
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check_for_broken_backtrace "stack is broken after disabling"
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check_info_unwinder "info unwinder after manually disabling" off
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# Now enable the unwinder using the 'enable unwinder' command.
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gdb_test "enable unwinder global \"test unwinder\"" \
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"1 unwinder enabled"
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check_for_fixed_backtrace "check backtrace after enabling with command"
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check_info_unwinder "info unwinder after command enabled" on
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# And now disable using the command and check the stack is once again
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# broken, and that the 'info unwinder' output updates correctly.
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gdb_test "disable unwinder global \"test unwinder\"" \
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"1 unwinder disabled"
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check_for_broken_backtrace "stack is broken after command disabling"
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check_info_unwinder "info unwinder after command disabling" off
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# Check that invalid register names and values cause errors.
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gdb_test "python print(add_saved_register_errors\[\"unknown_name\"\])" \
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"Bad register" \
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"add_saved_register error when an unknown register name is used"
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gdb_test "python print(add_saved_register_errors\[\"unknown_number\"\])" \
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"Bad register" \
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"add_saved_register error when an unknown register number is used"
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gdb_test "python print(add_saved_register_errors\[\"bad_value\"\])" \
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"argument 2 must be gdb.Value, not int" \
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"add_saved_register error when invalid register value is used"
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gdb_test "python print(read_register_error)" "Bad register" \
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"read_register error"
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# Try to create an unwinder object with a non-string name.
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gdb_test "python obj = simple_unwinder(True)" \
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[multi_line \
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"TypeError.*: incorrect type for name: <class 'bool'>" \
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"Error occurred in Python.*"]
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# Now register the simple_unwinder with a valid name, and use the
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# unwinder to capture a PendingFrame object.
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gdb_test_no_output "python obj = simple_unwinder(\"simple\")"
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gdb_test_no_output "python gdb.unwinder.register_unwinder(None, obj)"
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check_for_broken_backtrace "backtrace to capture a PendingFrame object"
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# Check the captured PendingFrame is not valid.
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gdb_test "python print(captured_pending_frame.is_valid())" "False"
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# Check the __repr__ of an invalid PendingFrame.
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gdb_test "python print(repr(captured_pending_frame))" \
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"<gdb.PendingFrame \\(invalid\\)>"
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# Check the __repr__ of an UnwindInfo for an invalid PendingFrame.
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gdb_test "python print(captured_unwind_info)"
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gdb_test "python print(repr(captured_unwind_info))" \
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"<gdb.UnwindInfo for an invalid frame>"
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# Check the repr of a PendingFrame that was copied (as a string) at a
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# time the PendingFrame was valid.
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gdb_test "python print(captured_pending_frame_repr)" \
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"<gdb.PendingFrame level=0, sp=$hex, pc=$hex>"
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# Check the repr of an UnwindInfo that was copied (as a string) at a
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# time the UnwindInfo was valid.
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gdb_test "python print(captured_unwind_info_repr)" \
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"<gdb.UnwindInfo frame #0, saved_regs=\\(rip, rbp, rsp\\)>"
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# Call methods on the captured gdb.PendingFrame and check we see the
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# expected error.
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gdb_test_no_output "python pf = captured_pending_frame"
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foreach cmd {"pf.read_register(\"pc\")" \
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"pf.create_unwind_info(None)" \
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"pf.architecture()" \
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"pf.level()" \
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"pf.name()" \
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"pf.pc()" \
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"pf.language()" \
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"pf.find_sal()" \
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"pf.block()" \
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"pf.function()" } {
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gdb_test "python $cmd" \
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[multi_line \
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"ValueError.*: gdb\\.PendingFrame is invalid\\." \
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"Error occurred in Python.*"]
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}
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# Turn on the useful unwinder so we have the full backtrace again, and
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# disable the simple unwinder -- because we can!
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gdb_test "enable unwinder global \"test unwinder\"" \
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"1 unwinder enabled" \
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"re-enable 'test unwinder' so we can check PendingFrame methods"
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gdb_test "disable unwinder global \"simple\"" \
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"1 unwinder disabled"
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check_for_fixed_backtrace \
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"check backtrace before testing PendingFrame methods"
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# Turn the 'simple' unwinder back on.
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gdb_test "enable unwinder global \"simple\"" \
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"1 unwinder enabled"
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# Replace the "simple" unwinder with a new version that doesn't set
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# the 'sp' attribute. Also the 'pc' attribute is invalid, but we'll
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# hit the missing 'sp' error first.
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with_test_prefix "frame-id 'sp' is None" {
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gdb_test_no_output "python obj = simple_unwinder(\"simple\", None, \"xyz\")"
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gdb_test_no_output "python gdb.unwinder.register_unwinder(None, obj, replace=True)"
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gdb_test_no_output "python captured_pending_frame = None"
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gdb_test "backtrace" \
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"Python Exception <class 'ValueError'>: frame_id should have 'sp' attribute\\.\r\n.*"
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}
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# Replace the "simple" unwinder with a new version that sets the 'sp'
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# attribute to an invalid value. Also the 'pc' attribute is invalid, but we'll
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# hit the invalid 'sp' error first.
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with_test_prefix "frame-id 'sp' is invalid" {
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gdb_test_no_output "python obj = simple_unwinder(\"simple\", \"jkl\", \"xyz\")"
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gdb_test_no_output "python gdb.unwinder.register_unwinder(None, obj, replace=True)"
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gdb_test_no_output "python captured_pending_frame = None"
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gdb_test "backtrace" \
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"Python Exception <class 'ValueError'>: invalid literal for int\\(\\) with base 10: 'jkl'\r\n.*"
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}
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# Replace the "simple" unwinder with a new version that sets the 'sp'
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# to a valid value, but set the 'pc' attribute to an invalid value.
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with_test_prefix "frame-id 'pc' is invalid" {
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gdb_test_no_output "python obj = simple_unwinder(\"simple\", 0x123, \"xyz\")"
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gdb_test_no_output "python gdb.unwinder.register_unwinder(None, obj, replace=True)"
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gdb_test_no_output "python captured_pending_frame = None"
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gdb_test "backtrace" \
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"Python Exception <class 'ValueError'>: invalid literal for int\\(\\) with base 10: 'xyz'\r\n.*"
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}
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with_test_prefix "bad object unwinder" {
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gdb_test_no_output "python obj = bad_object_unwinder(\"bad-object\")"
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gdb_test_no_output "python gdb.unwinder.register_unwinder(None, obj, replace=True)"
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gdb_test "backtrace" \
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"Python Exception <class 'gdb.error'>: an Unwinder should return gdb.UnwindInfo, not Blah\\.\r\n.*"
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}
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# Gather information about every frame.
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gdb_test_no_output "python capture_all_frame_information()"
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gdb_test_no_output "python gdb.newest_frame().select()"
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gdb_test_no_output "python pspace = gdb.selected_inferior().progspace"
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gdb_test_no_output "python obj = validating_unwinder()"
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gdb_test_no_output "python gdb.unwinder.register_unwinder(pspace, obj)"
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check_for_fixed_backtrace \
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"check backtrace to validate all information"
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gdb_test_no_output "python check_all_frame_information_matched()"
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# Check we can't sub-class from gdb.UnwindInfo.
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gdb_test_multiline "Sub-class gdb.UnwindInfo " \
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"python" "" \
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"class my_unwind_info(gdb.UnwindInfo):" "" \
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" def __init__(self):" "" \
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" pass" "" \
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"end" \
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[multi_line \
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"TypeError.*: type 'gdb\\.UnwindInfo' is not an acceptable base type" \
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"Error occurred in Python.*"]
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# Check we can't directly instantiate a gdb.UnwindInfo.
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gdb_test "python uw = gdb.UnwindInfo()" \
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[multi_line \
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"TypeError.*: cannot create 'gdb\\.UnwindInfo' instances" \
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"Error occurred in Python.*"]
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