From 66bd1b294d8e5b460d6b9c645d2db529f4c441de Mon Sep 17 00:00:00 2001 From: Andrew Burgess Date: Wed, 21 Sep 2022 14:40:30 +0100 Subject: [PATCH] gdb/python: break dependencies between gdbpy_initialize_* functions In a later commit in this series I will propose removing all of the explicit gdbpy_initialize_* calls from python.c and replace these calls with a more generic mechanism. One of the side effects of this generic mechanism is that the order in which the various Python sub-systems within GDB are initialized is no longer guaranteed. On the whole I don't think this matters, most of the sub-systems are independent of each other, though testing did reveal a few places where we did have dependencies, though I don't think those dependencies were explicitly documented in a comment anywhere. This commit removes the first dependency issue, with this and the next commit, all of the implicit inter-sub-system dependencies will be replaced by explicit dependencies, which will allow me to, I think, clean up how the sub-systems are initialized. The dependency is around the py_insn_type. This type is setup in gdbpy_initialize_instruction and used in gdbpy_initialize_record. Rather than depend on the calls to these two functions being in a particular order, in this commit I propose adding a new function py_insn_get_insn_type. This function will take care of setting up the py_insn_type type and calling PyType_Ready. This helper function can be called from gdbpy_initialize_record and gdbpy_initialize_instruction, and the py_insn_type will be initialized just once. To me this is better, the dependency is now really obvious, but also, we no longer care in which order gdbpy_initialize_record and gdbpy_initialize_instruction are called. There should be no user visible changes after this commit. --- gdb/python/py-instruction.c | 41 +++++++++++++++++++++++++++++-------- gdb/python/py-instruction.h | 13 ++++++++---- gdb/python/py-record.c | 2 +- 3 files changed, 42 insertions(+), 14 deletions(-) diff --git a/gdb/python/py-instruction.c b/gdb/python/py-instruction.c index e1ad49a5143..fee5bba4015 100644 --- a/gdb/python/py-instruction.c +++ b/gdb/python/py-instruction.c @@ -20,7 +20,9 @@ #include "defs.h" #include "py-instruction.h" -/* See py-instruction.h. */ +/* Python type object for the abstract gdb.Instruction class. This class + contains getters for four elements: "pc" (int), "data" (buffer), "decode" + (str) and "size" (int) that must be overridden by sub classes. */ PyTypeObject py_insn_type = { PyVarObject_HEAD_INIT (NULL, 0) @@ -51,17 +53,38 @@ static gdb_PyGetSetDef py_insn_getset[] = {NULL} }; +/* See py-instruction.h. */ + +PyTypeObject * +py_insn_get_insn_type () +{ + if (py_insn_type.tp_new == nullptr) + { + py_insn_type.tp_new = PyType_GenericNew; + py_insn_type.tp_flags = Py_TPFLAGS_DEFAULT; + py_insn_type.tp_basicsize = sizeof (py_insn_obj); + py_insn_type.tp_name = "gdb.Instruction"; + py_insn_type.tp_doc = "GDB instruction object"; + py_insn_type.tp_getset = py_insn_getset; + + if (PyType_Ready (&py_insn_type) < 0) + { + /* Reset the tp_new field so any subsequent calls to this + function will retry to make the type ready. */ + py_insn_type.tp_new = nullptr; + return nullptr; + } + } + + return &py_insn_type; +} + /* Sets up the gdb.Instruction type. */ int gdbpy_initialize_instruction (void) { - py_insn_type.tp_new = PyType_GenericNew; - py_insn_type.tp_flags = Py_TPFLAGS_DEFAULT; - py_insn_type.tp_basicsize = sizeof (py_insn_obj); - py_insn_type.tp_name = "gdb.Instruction"; - py_insn_type.tp_doc = "GDB instruction object"; - py_insn_type.tp_getset = py_insn_getset; - - return PyType_Ready (&py_insn_type); + if (py_insn_get_insn_type () == nullptr) + return -1; + return 0; } diff --git a/gdb/python/py-instruction.h b/gdb/python/py-instruction.h index 59f0893e641..1e602636a39 100644 --- a/gdb/python/py-instruction.h +++ b/gdb/python/py-instruction.h @@ -22,9 +22,14 @@ #include "python-internal.h" -/* Python type object for the abstract gdb.Instruction class. This class - contains getters for four elements: "pc" (int), "data" (buffer), "decode" - (str) and "size" (int) that must be overridden by sub classes. */ -extern PyTypeObject py_insn_type; +/* Return a pointer to the py_insn_type object (see py-instruction.c), but + ensure that PyType_Ready has been called for the type first. If the + PyType_Ready call is successful then subsequent calls to this function + will not call PyType_Ready, the type pointer will just be returned. + + If the PyType_Ready call is not successful then nullptr is returned and + subsequent calls to this function will call PyType_Ready again. */ + +extern PyTypeObject *py_insn_get_insn_type (); #endif /* PYTHON_PY_INSTRUCTION_H */ diff --git a/gdb/python/py-record.c b/gdb/python/py-record.c index 51084dfac72..fd5cfee84eb 100644 --- a/gdb/python/py-record.c +++ b/gdb/python/py-record.c @@ -563,7 +563,7 @@ gdbpy_initialize_record (void) recpy_insn_type.tp_getset = recpy_insn_getset; recpy_insn_type.tp_richcompare = recpy_element_richcompare; recpy_insn_type.tp_hash = recpy_element_hash; - recpy_insn_type.tp_base = &py_insn_type; + recpy_insn_type.tp_base = py_insn_get_insn_type (); recpy_func_type.tp_new = PyType_GenericNew; recpy_func_type.tp_flags = Py_TPFLAGS_DEFAULT; -- 2.30.2