From 0b233e34c801eac78a5e03b66f18585cf368e4d5 Mon Sep 17 00:00:00 2001 From: Andrew Burgess Date: Wed, 1 Sep 2021 14:24:15 +0100 Subject: [PATCH] gdb/python: remove all uses of Py_TPFLAGS_HAVE_ITER Python 2 has a bit flag Py_TPFLAGS_HAVE_ITER which can be passed as part of the tp_flags field when defining a new object type. This flag is not defined in Python 3 and so we define it to 0 in python-internal.h (when IS_PY3K is defined). The meaning of this flag is that the object has the fields tp_iter and tp_iternext. Note the use of "has" here, the flag says nothing about the values in those fields, just that the type object has the fields. In early versions of Python 2 these fields were no part of the PyTypeObject struct, they were added in version 2.2 (see https://docs.python.org/release/2.3/api/type-structs.html). And so, there could be a some code compiled out there which has a PyTypeObject structure within it that doesn't even have the tp_iter and tp_iternext fields, attempting to access these fields would be undefined behaviour. And so Python added the Py_TPFLAGS_HAVE_ITER flag. If the flag is present then Python is free to access the tp_iter and tp_iternext fields. If we consider GDB then we always assume that the tp_iter and tp_iternext fields are part of PyTypeObject. If someone was crazy enough to try and compile GDB against Python 2.1 then we'd get lots of build errors saying that we were passing too many fields when initializing PyTypeObject structures. And so, I claim, we can be sure that GDB will always be compiled with a version of Python that has the tp_iter and tp_iternext fields in PyTypeObject. Next we can look at the Py_TPFLAGS_DEFAULT flag. In Python 2, each time additional fields are added to PyTypeObject a new Py_TPFLAGS_* flag would be defined to indicate whether those flags are present or not. And, those new flags would be added to Py_TPFLAGS_DEFAULT. And so, in the latest version of Python 2 the Py_TPFLAGS_DEFAULT flag includes Py_TPFLAGS_HAVE_ITER (see https://docs.python.org/2.7/c-api/typeobj.html). In GDB we pass Py_TPFLAGS_DEFAULT as part of the tp_flags for all objects we define. And so, in this commit, I propose to remove all uses of Py_TPFLAGS_HAVE_ITER from GDB, it's simply not needed. There should be no user visible changes after this commit. --- gdb/python/py-block.c | 4 ++-- gdb/python/py-inferior.c | 2 +- gdb/python/py-infthread.c | 2 +- gdb/python/py-linetable.c | 2 +- gdb/python/py-registers.c | 4 ++-- gdb/python/py-type.c | 6 +++--- gdb/python/python-internal.h | 1 - 7 files changed, 10 insertions(+), 11 deletions(-) diff --git a/gdb/python/py-block.c b/gdb/python/py-block.c index 244ff9a6bab..fe0efd62d46 100644 --- a/gdb/python/py-block.c +++ b/gdb/python/py-block.c @@ -510,7 +510,7 @@ PyTypeObject block_object_type = { 0, /*tp_getattro*/ 0, /*tp_setattro*/ 0, /*tp_as_buffer*/ - Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_ITER, /*tp_flags*/ + Py_TPFLAGS_DEFAULT, /*tp_flags*/ "GDB block object", /* tp_doc */ 0, /* tp_traverse */ 0, /* tp_clear */ @@ -550,7 +550,7 @@ PyTypeObject block_syms_iterator_object_type = { 0, /*tp_getattro*/ 0, /*tp_setattro*/ 0, /*tp_as_buffer*/ - Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_ITER, /*tp_flags*/ + Py_TPFLAGS_DEFAULT, /*tp_flags*/ "GDB block syms iterator object", /*tp_doc */ 0, /*tp_traverse */ 0, /*tp_clear */ diff --git a/gdb/python/py-inferior.c b/gdb/python/py-inferior.c index cfbc2f6574f..0659c28ea9c 100644 --- a/gdb/python/py-inferior.c +++ b/gdb/python/py-inferior.c @@ -1026,7 +1026,7 @@ PyTypeObject inferior_object_type = 0, /* tp_getattro */ 0, /* tp_setattro */ 0, /* tp_as_buffer */ - Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_ITER, /* tp_flags */ + Py_TPFLAGS_DEFAULT, /* tp_flags */ "GDB inferior object", /* tp_doc */ 0, /* tp_traverse */ 0, /* tp_clear */ diff --git a/gdb/python/py-infthread.c b/gdb/python/py-infthread.c index 3315af5eb59..5645442a426 100644 --- a/gdb/python/py-infthread.c +++ b/gdb/python/py-infthread.c @@ -408,7 +408,7 @@ PyTypeObject thread_object_type = 0, /*tp_getattro*/ 0, /*tp_setattro*/ 0, /*tp_as_buffer*/ - Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_ITER, /*tp_flags*/ + Py_TPFLAGS_DEFAULT, /*tp_flags*/ "GDB thread object", /* tp_doc */ 0, /* tp_traverse */ 0, /* tp_clear */ diff --git a/gdb/python/py-linetable.c b/gdb/python/py-linetable.c index e989204a7f5..071341f6ceb 100644 --- a/gdb/python/py-linetable.c +++ b/gdb/python/py-linetable.c @@ -531,7 +531,7 @@ PyTypeObject ltpy_iterator_object_type = { 0, /*tp_getattro*/ 0, /*tp_setattro*/ 0, /*tp_as_buffer*/ - Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_ITER, /*tp_flags*/ + Py_TPFLAGS_DEFAULT, /*tp_flags*/ "GDB line table iterator object", /*tp_doc */ 0, /*tp_traverse */ 0, /*tp_clear */ diff --git a/gdb/python/py-registers.c b/gdb/python/py-registers.c index 04e554f48e1..df0ba764b46 100644 --- a/gdb/python/py-registers.c +++ b/gdb/python/py-registers.c @@ -497,7 +497,7 @@ PyTypeObject register_descriptor_iterator_object_type = { 0, /*tp_getattro*/ 0, /*tp_setattro*/ 0, /*tp_as_buffer*/ - Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_ITER, /*tp_flags*/ + Py_TPFLAGS_DEFAULT, /*tp_flags*/ "GDB architecture register descriptor iterator object", /*tp_doc */ 0, /*tp_traverse */ 0, /*tp_clear */ @@ -567,7 +567,7 @@ PyTypeObject reggroup_iterator_object_type = { 0, /*tp_getattro*/ 0, /*tp_setattro*/ 0, /*tp_as_buffer*/ - Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_ITER, /*tp_flags*/ + Py_TPFLAGS_DEFAULT, /*tp_flags*/ "GDB register groups iterator object", /*tp_doc */ 0, /*tp_traverse */ 0, /*tp_clear */ diff --git a/gdb/python/py-type.c b/gdb/python/py-type.c index 04d1c7a0ee7..d82bdf84957 100644 --- a/gdb/python/py-type.c +++ b/gdb/python/py-type.c @@ -1633,7 +1633,7 @@ PyTypeObject type_object_type = 0, /*tp_getattro*/ 0, /*tp_setattro*/ 0, /*tp_as_buffer*/ - Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_ITER, /*tp_flags*/ + Py_TPFLAGS_DEFAULT, /*tp_flags*/ "GDB type object", /* tp_doc */ 0, /* tp_traverse */ 0, /* tp_clear */ @@ -1682,7 +1682,7 @@ PyTypeObject field_object_type = 0, /*tp_getattro*/ 0, /*tp_setattro*/ 0, /*tp_as_buffer*/ - Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_ITER, /*tp_flags*/ + Py_TPFLAGS_DEFAULT, /*tp_flags*/ "GDB field object", /* tp_doc */ 0, /* tp_traverse */ 0, /* tp_clear */ @@ -1723,7 +1723,7 @@ PyTypeObject type_iterator_object_type = { 0, /*tp_getattro*/ 0, /*tp_setattro*/ 0, /*tp_as_buffer*/ - Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_ITER, /*tp_flags*/ + Py_TPFLAGS_DEFAULT, /*tp_flags*/ "GDB type iterator object", /*tp_doc */ 0, /*tp_traverse */ 0, /*tp_clear */ diff --git a/gdb/python/python-internal.h b/gdb/python/python-internal.h index 0e140f1af61..368681b797c 100644 --- a/gdb/python/python-internal.h +++ b/gdb/python/python-internal.h @@ -92,7 +92,6 @@ #endif #ifdef IS_PY3K -#define Py_TPFLAGS_HAVE_ITER 0 #define Py_TPFLAGS_CHECKTYPES 0 #define PyInt_Check PyLong_Check -- 2.30.2