From 4e317a765bbe1c47fb9d461b7effa40f34220c85 Mon Sep 17 00:00:00 2001 From: Simon Marchi Date: Tue, 22 Jun 2021 14:16:01 -0400 Subject: [PATCH] gdb/python: print name of unwinder that claimed frame in debug message If we have multiple registered unwinders, this will helps identify which unwinder was chosen and make it easier to track down potential problems. Unwinders have a mandatory name argument, which we can use in the message. First, make gdb._execute_unwinders return a tuple containing the name, in addition to the UnwindInfo. Then, make pyuw_sniffer include the name in the debug message. I moved the debug message earlier. I think it's good to print it as early as possible, so that we see it in case an assert is hit in the loop below, for example. gdb/ChangeLog: * python/lib/gdb/__init__.py (_execute_unwinders): Return tuple with name of chosen unwinder. * python/py-unwind.c (pyuw_sniffer): Print name of chosen unwinder in debug message. Change-Id: Id603545b44a97df2a39dd1872fe1f38ad5059f03 --- gdb/ChangeLog | 7 +++++++ gdb/python/lib/gdb/__init__.py | 14 +++++++++---- gdb/python/py-unwind.c | 36 +++++++++++++++++++++++++++------- 3 files changed, 46 insertions(+), 11 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index d9e0a3a4f4d..995c8a1a375 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,10 @@ +2021-06-22 Simon Marchi + + * python/lib/gdb/__init__.py (_execute_unwinders): Return tuple + with name of chosen unwinder. + * python/py-unwind.c (pyuw_sniffer): Print name of chosen + unwinder in debug message. + 2021-06-22 Andreas Schwab PR symtab/27999 diff --git a/gdb/python/lib/gdb/__init__.py b/gdb/python/lib/gdb/__init__.py index d748b3a5827..f2f38b32af9 100644 --- a/gdb/python/lib/gdb/__init__.py +++ b/gdb/python/lib/gdb/__init__.py @@ -90,27 +90,33 @@ def _execute_unwinders(pending_frame): Arguments: pending_frame: gdb.PendingFrame instance. + Returns: - gdb.UnwindInfo instance or None. + Tuple with: + + [0] gdb.UnwindInfo instance + [1] Name of unwinder that claimed the frame (type `str`) + + or None, if no unwinder has claimed the frame. """ for objfile in objfiles(): for unwinder in objfile.frame_unwinders: if unwinder.enabled: unwind_info = unwinder(pending_frame) if unwind_info is not None: - return unwind_info + return (unwind_info, unwinder.name) for unwinder in current_progspace().frame_unwinders: if unwinder.enabled: unwind_info = unwinder(pending_frame) if unwind_info is not None: - return unwind_info + return (unwind_info, unwinder.name) for unwinder in frame_unwinders: if unwinder.enabled: unwind_info = unwinder(pending_frame) if unwind_info is not None: - return unwind_info + return (unwind_info, unwinder.name) return None diff --git a/gdb/python/py-unwind.c b/gdb/python/py-unwind.c index d3ef1911ab8..18ea2434f87 100644 --- a/gdb/python/py-unwind.c +++ b/gdb/python/py-unwind.c @@ -556,33 +556,56 @@ pyuw_sniffer (const struct frame_unwind *self, struct frame_info *this_frame, } gdbpy_ref<> pyo_execute (PyObject_GetAttrString (gdb_python_module, "_execute_unwinders")); - if (pyo_execute == NULL) + if (pyo_execute == nullptr) { gdbpy_print_stack (); return 0; } - gdbpy_ref<> pyo_unwind_info + /* A (gdb.UnwindInfo, str) tuple, or None. */ + gdbpy_ref<> pyo_execute_ret (PyObject_CallFunctionObjArgs (pyo_execute.get (), pyo_pending_frame.get (), NULL)); - if (pyo_unwind_info == NULL) + if (pyo_execute_ret == nullptr) { /* If the unwinder is cancelled due to a Ctrl-C, then propagate the Ctrl-C as a GDB exception instead of swallowing it. */ gdbpy_print_stack_or_quit (); return 0; } - if (pyo_unwind_info == Py_None) + if (pyo_execute_ret == Py_None) return 0; + /* Verify the return value of _execute_unwinders is a tuple of size 2. */ + gdb_assert (PyTuple_Check (pyo_execute_ret.get ())); + gdb_assert (PyTuple_GET_SIZE (pyo_execute_ret.get ()) == 2); + + if (pyuw_debug) + { + PyObject *pyo_unwinder_name = PyTuple_GET_ITEM (pyo_execute_ret.get (), 1); + gdb::unique_xmalloc_ptr name + = python_string_to_host_string (pyo_unwinder_name); + + /* This could happen if the user passed something else than a string + as the unwinder's name. */ + if (name == nullptr) + { + gdbpy_print_stack (); + name = make_unique_xstrdup (""); + } + + pyuw_debug_printf ("frame claimed by unwinder %s", name.get ()); + } + /* Received UnwindInfo, cache data. */ - if (PyObject_IsInstance (pyo_unwind_info.get (), + PyObject *pyo_unwind_info = PyTuple_GET_ITEM (pyo_execute_ret.get (), 0); + if (PyObject_IsInstance (pyo_unwind_info, (PyObject *) &unwind_info_object_type) <= 0) error (_("A Unwinder should return gdb.UnwindInfo instance.")); { unwind_info_object *unwind_info = - (unwind_info_object *) pyo_unwind_info.get (); + (unwind_info_object *) pyo_unwind_info; int reg_count = unwind_info->saved_regs->size (); cached_frame @@ -613,7 +636,6 @@ pyuw_sniffer (const struct frame_unwind *self, struct frame_info *this_frame, } *cache_ptr = cached_frame; - pyuw_debug_printf ("frame claimed"); return 1; } -- 2.30.2