From 0af2f233330024e0e9b4697d510c7030e518e64c Mon Sep 17 00:00:00 2001 From: Andrew Burgess Date: Mon, 23 Jan 2023 15:31:28 +0000 Subject: gdb/python: rework how the disassembler API reads the result object This commit is a refactor ahead of the next change which will make disassembler styling available through the Python API. Unfortunately, in order to make the styling support available, I think the easiest solution is to make a very small change to the existing API. The current API relies on returning a DisassemblerResult object to represent each disassembled instruction. Currently GDB allows the DisassemblerResult class to be sub-classed, which could mean that a user tries to override the various attributes that exist on the DisassemblerResult object. This commit removes this ability, effectively making the DisassemblerResult class final. Though this is a change to the existing API, I'm hoping this isn't going to cause too many issues: - The Python disassembler API was only added in the previous release of GDB, so I don't expect it to be widely used yet, and - It's not clear to me why a user would need to sub-class the DisassemblerResult type, I allowed it in the original patch because at the time I couldn't see any reason to NOT allow it. Having prevented sub-classing I can now rework the tail end of the gdbpy_print_insn function; instead of pulling the results out of the DisassemblerResult object by calling back into Python, I now cast the Python object back to its C++ type (disasm_result_object), and access the fields directly from there. In later commits I will be reworking the disasm_result_object type in order to hold information about the styled disassembler output. The tests that dealt with sub-classing DisassemblerResult have been removed, and a new test that confirms that DisassemblerResult can't be sub-classed has been added. Reviewed-By: Eli Zaretskii Reviewed-By: Tom Tromey --- gdb/NEWS | 3 ++ gdb/doc/python.texi | 2 ++ gdb/python/py-disasm.c | 54 +++++++++------------------------- gdb/testsuite/gdb.python/py-disasm.exp | 15 ++++++++-- gdb/testsuite/gdb.python/py-disasm.py | 37 ----------------------- 5 files changed, 31 insertions(+), 80 deletions(-) diff --git a/gdb/NEWS b/gdb/NEWS index 6aa0d5171f2..ca164257126 100644 --- a/gdb/NEWS +++ b/gdb/NEWS @@ -170,6 +170,9 @@ info main (program-counter) values, and can be used as the frame-id when calling gdb.PendingFrame.create_unwind_info. + ** It is now no longer possible to sub-class the + gdb.disassembler.DisassemblerResult type. + *** Changes in GDB 13 * MI version 1 is deprecated, and will be removed in GDB 14. diff --git a/gdb/doc/python.texi b/gdb/doc/python.texi index 11135910656..a906c168373 100644 --- a/gdb/doc/python.texi +++ b/gdb/doc/python.texi @@ -7032,6 +7032,8 @@ instance of this class should be returned from @w{@code{Disassembler.__call__}} (@pxref{Disassembler Class}) if an instruction was successfully disassembled. +It is not possible to sub-class the @code{DisassemblerResult} class. + The @code{DisassemblerResult} class has the following properties and methods: diff --git a/gdb/python/py-disasm.c b/gdb/python/py-disasm.c index 9c281f6e089..f246a093014 100644 --- a/gdb/python/py-disasm.c +++ b/gdb/python/py-disasm.c @@ -904,43 +904,14 @@ gdbpy_print_insn (struct gdbarch *gdbarch, CORE_ADDR memaddr, return gdb::optional (-1); } - /* The call into Python neither raised an exception, or returned None. - Check to see if the result looks valid. */ - gdbpy_ref<> length_obj (PyObject_GetAttrString (result.get (), "length")); - if (length_obj == nullptr) - { - gdbpy_print_stack (); - return gdb::optional (-1); - } - - gdbpy_ref<> string_obj (PyObject_GetAttrString (result.get (), "string")); - if (string_obj == nullptr) - { - gdbpy_print_stack (); - return gdb::optional (-1); - } - if (!gdbpy_is_string (string_obj.get ())) - { - PyErr_SetString (PyExc_TypeError, _("String attribute is not a string.")); - gdbpy_print_stack (); - return gdb::optional (-1); - } - - gdb::unique_xmalloc_ptr string - = gdbpy_obj_to_string (string_obj.get ()); - if (string == nullptr) - { - gdbpy_print_stack (); - return gdb::optional (-1); - } - - long length; - if (!gdb_py_int_as_long (length_obj.get (), &length)) - { - gdbpy_print_stack (); - return gdb::optional (-1); - } - + /* The result from the Python disassembler has the correct type. Convert + this back to the underlying C++ object and read the state directly + from this object. */ + struct disasm_result_object *result_obj + = (struct disasm_result_object *) result.get (); + + /* Validate the length of the disassembled instruction. */ + long length = result_obj->length; long max_insn_length = (gdbarch_max_insn_length_p (gdbarch) ? gdbarch_max_insn_length (gdbarch) : INT_MAX); if (length <= 0) @@ -961,7 +932,10 @@ gdbpy_print_insn (struct gdbarch *gdbarch, CORE_ADDR memaddr, return gdb::optional (-1); } - if (strlen (string.get ()) == 0) + /* Validate the text of the disassembled instruction. */ + gdb_assert (result_obj->content != nullptr); + std::string string (std::move (result_obj->content->release ())); + if (strlen (string.c_str ()) == 0) { PyErr_SetString (PyExc_ValueError, _("String attribute must not be empty.")); @@ -971,7 +945,7 @@ gdbpy_print_insn (struct gdbarch *gdbarch, CORE_ADDR memaddr, /* Print the disassembled instruction back to core GDB, and return the length of the disassembled instruction. */ - info->fprintf_func (info->stream, "%s", string.get ()); + info->fprintf_func (info->stream, "%s", string.c_str ()); return gdb::optional (length); } @@ -1159,7 +1133,7 @@ PyTypeObject disasm_result_object_type = { 0, /*tp_getattro*/ 0, /*tp_setattro*/ 0, /*tp_as_buffer*/ - Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /*tp_flags*/ + Py_TPFLAGS_DEFAULT, /*tp_flags*/ "GDB object, representing a disassembler result", /* tp_doc */ 0, /* tp_traverse */ 0, /* tp_clear */ diff --git a/gdb/testsuite/gdb.python/py-disasm.exp b/gdb/testsuite/gdb.python/py-disasm.exp index 2550e60111e..5cbf02fc9fe 100644 --- a/gdb/testsuite/gdb.python/py-disasm.exp +++ b/gdb/testsuite/gdb.python/py-disasm.exp @@ -96,9 +96,7 @@ set test_plans \ [list "ReadMemoryCaughtRuntimeErrorDisassembler" "${addr_pattern}${nop}\r\n.*"] \ [list "MemorySourceNotABufferDisassembler" "${addr_pattern}Python Exception : Result from read_memory is not a buffer\r\n\r\n${unknown_error_pattern}"] \ [list "MemorySourceBufferTooLongDisassembler" "${addr_pattern}Python Exception : Buffer returned from read_memory is sized $decimal instead of the expected $decimal\r\n\r\n${unknown_error_pattern}"] \ - [list "ResultOfWrongType" "${addr_pattern}Python Exception : Result is not a DisassemblerResult.\r\n.*"] \ - [list "ResultWithInvalidLength" "${addr_pattern}Python Exception : Invalid length attribute: length must be greater than 0.\r\n.*"] \ - [list "ResultWithInvalidString" "${addr_pattern}Python Exception : String attribute must not be empty.\r\n.*"]] + [list "ResultOfWrongType" "${addr_pattern}Python Exception : Result is not a DisassemblerResult.\r\n.*"]] # Now execute each test plan. foreach plan $test_plans { @@ -217,3 +215,14 @@ with_test_prefix "Bad DisassembleInfo creation" { "RuntimeError: DisassembleInfo is no longer valid\\." \ "Error while executing Python code\\."] } + +# Test that we can't inherit from the DisassemblerResult class. +gdb_test_multiline "Sub-class a breakpoint" \ + "python" "" \ + "class InvalidResultType(gdb.disassembler.DisassemblerResult):" "" \ + " def __init__(self):" "" \ + " pass" "" \ + "end" \ + [multi_line \ + "TypeError: type 'gdb\\.disassembler\\.DisassemblerResult' is not an acceptable base type" \ + "Error while executing Python code\\."] diff --git a/gdb/testsuite/gdb.python/py-disasm.py b/gdb/testsuite/gdb.python/py-disasm.py index 435a3bf5339..17a7e752935 100644 --- a/gdb/testsuite/gdb.python/py-disasm.py +++ b/gdb/testsuite/gdb.python/py-disasm.py @@ -274,43 +274,6 @@ class ResultOfWrongType(TestDisassembler): return self.Blah(1, "ABC") -class ResultWrapper(gdb.disassembler.DisassemblerResult): - def __init__(self, length, string, length_x=None, string_x=None): - super().__init__(length, string) - if length_x is None: - self.__length = length - else: - self.__length = length_x - if string_x is None: - self.__string = string - else: - self.__string = string_x - - @property - def length(self): - return self.__length - - @property - def string(self): - return self.__string - - -class ResultWithInvalidLength(TestDisassembler): - """Return a result object with an invalid length.""" - - def disassemble(self, info): - result = gdb.disassembler.builtin_disassemble(info) - return ResultWrapper(result.length, result.string, 0) - - -class ResultWithInvalidString(TestDisassembler): - """Return a result object with an empty string.""" - - def disassemble(self, info): - result = gdb.disassembler.builtin_disassemble(info) - return ResultWrapper(result.length, result.string, None, "") - - class TaggingDisassembler(TestDisassembler): """A simple disassembler that just tags the output.""" -- cgit v1.2.1