72 lines
2.9 KiB
Text
72 lines
2.9 KiB
Text
# Copyright 2021-2022 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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# Make an inferior call to a function which uses longjmp. However,
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# the backtrace for the function that is called is broken at the point
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# where the longjmp is handled. This test is checking to see if the
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# inferior call still completes successfully.
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#
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# This test forces a broken backtrace using Python, but in real life a
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# broken backtrace can easily occur when calling through code for
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# which there is no debug information if the prologue unwinder fails,
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# which can often happen if the code has been optimized.
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#
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# The problem was that, due to the broken backtrace, GDB failed to
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# find the inferior call's dummy frame. GDB then concluded that the
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# inferior had longjmp'd backward past the dummy frame and so garbage
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# collected the dummy frame, this causes the breakpoint within the
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# dummy frame to be deleted.
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#
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# When the inferior continued, and eventually returned to the dummy
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# frame, it would try to execute instruction from the dummy frame
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# (which for most, or even all, targets, is on the stack), and then
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# experience undefined behaviuor, often a SIGSEGV.
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standard_testfile .c
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if { [prepare_for_testing "failed to prepare" $testfile $srcfile] } {
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return -1
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}
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if ![runto_main] then {
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return 0
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}
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# Skip this test if Python scripting is not enabled.
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if { [skip_python_tests] } { continue }
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set pyfile [gdb_remote_download host ${srcdir}/${subdir}/${testfile}.py]
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gdb_test_no_output "source ${pyfile}" "load python file"
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gdb_test "p some_func ()" " = 0"
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# When frame debugging is turned on, this test has (previously)
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# revealed some crashes due to the Python frame unwinder trying to
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# read registers.
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#
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# Enable frame debug and rerun the test. We don't bother checking the
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# output of calling 'p some_func ()' as the output will be full of
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# debug, to format of which isn't fixed. All we care about is that
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# GDB is still running afterwards.
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#
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# All of the debug output makes this really slow when testing with the
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# special read1 version of expect, hence the timeout factor.
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with_read1_timeout_factor 10 {
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gdb_test_no_output "set debug frame on"
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gdb_test "p some_func ()" ".*" \
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"repeat p some_func () with frame debug on"
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gdb_test_no_output "set debug frame off"
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}
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gdb_test "p 1 + 2 + 3" " = 6"
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