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Without any explicit dependencies specified, the observers attached to the 'gdb::observers::new_objfile' observable are always notified in the order in which they have been attached. The new_objfile observer callback to auto-load scripts is attached in '_initialize_auto_load'. The new_objfile observer callback that propagates the new_objfile event to the Python side is attached in 'gdbpy_initialize_inferior', which is called via '_initialize_python'. With '_initialize_python' happening before '_initialize_auto_load', the consequence was that the new_objfile event was emitted on the Python side before autoloaded scripts had been executed when a new objfile was loaded. As a result, trying to access the objfile's pretty printers (defined in the autoloaded script) from a handler for the Python-side 'new_objfile' event would fail. Those would only be initialized later on (when the 'auto_load_new_objfile' callback was called). To make sure that the objfile passed to the Python event handler is properly initialized (including its 'pretty_printers' member), make sure that the 'auto_load_new_objfile' observer is notified before the 'python_new_objfile' one that propagates the event to the Python side. To do this, make use of the mechanism to explicitly specify dependencies between observers (introduced in a preparatory commit). Add a corresponding testcase that involves a test library with an autoloaded Python script and a handler for the Python 'new_objfile' event. (The real world use case where I came across this issue was in an attempt to extend handling for GDB pretty printers for dynamically loaded objfiles in the Qt Creator IDE, s. [1] and [2] for more background.) [1] https://bugreports.qt.io/browse/QTCREATORBUG-25339 [2] https://codereview.qt-project.org/c/qt-creator/qt-creator/+/333857/1 Tested on x86_64-linux (Debian testing). gdb/ChangeLog: * gdb/auto-load.c (_initialize_auto_load): 'Specify token when attaching the 'auto_load_new_objfile' observer, so other observers can specify it as a dependency. * gdb/auto-load.h (struct token): Declare 'auto_load_new_objfile_observer_token' as token to be used for the 'auto_load_new_objfile' observer. * gdb/python/py-inferior.c (gdbpy_initialize_inferior): Make 'python_new_objfile' observer depend on 'auto_load_new_objfile' observer, so it gets notified after the latter. gdb/testsuite/ChangeLog: * gdb.python/libpy-autoloaded-pretty-printers-in-newobjfile-event.so-gdb.py: New test. * gdb.python/py-autoloaded-pretty-printers-in-newobjfile-event-lib.cc: New test. * gdb.python/py-autoloaded-pretty-printers-in-newobjfile-event-lib.h: New test. * gdb.python/py-autoloaded-pretty-printers-in-newobjfile-event-main.cc: New test. * gdb.python/py-autoloaded-pretty-printers-in-newobjfile-event.exp: New test. * gdb.python/py-autoloaded-pretty-printers-in-newobjfile-event.py: New test. Change-Id: I8275b3f4c3bec32e56dd7892f9a59d89544edf89
28 lines
925 B
C++
28 lines
925 B
C++
/* This testcase is part of GDB, the GNU debugger.
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Copyright 2021 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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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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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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#include "py-autoloaded-pretty-printers-in-newobjfile-event-lib.h"
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MyClassTestLib::MyClassTestLib (int theId)
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{
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id = theId;
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}
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int MyClassTestLib::getId ()
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{
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return id;
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}
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