This patch splits the TRY_CATCH macro into three, so that we go from
this:
~~~
volatile gdb_exception ex;
TRY_CATCH (ex, RETURN_MASK_ERROR)
{
}
if (ex.reason < 0)
{
}
~~~
to this:
~~~
TRY
{
}
CATCH (ex, RETURN_MASK_ERROR)
{
}
END_CATCH
~~~
Thus, we'll be getting rid of the local volatile exception object, and
declaring the caught exception in the catch block.
This allows reimplementing TRY/CATCH in terms of C++ exceptions when
building in C++ mode, while still allowing to build GDB in C mode
(using setjmp/longjmp), as a transition step.
TBC, after this patch, is it _not_ valid to have code between the TRY
and the CATCH blocks, like:
TRY
{
}
// some code here.
CATCH (ex, RETURN_MASK_ERROR)
{
}
END_CATCH
Just like it isn't valid to do that with C++'s native try/catch.
By switching to creating the exception object inside the CATCH block
scope, we can get rid of all the explicitly allocated volatile
exception objects all over the tree, and map the CATCH block more
directly to C++'s catch blocks.
The majority of the TRY_CATCH -> TRY+CATCH+END_CATCH conversion was
done with a script, rerun from scratch at every rebase, no manual
editing involved. After the mechanical conversion, a few places
needed manual intervention, to fix preexisting cases where we were
using the exception object outside of the TRY_CATCH block, and cases
where we were using "else" after a 'if (ex.reason) < 0)' [a CATCH
after this patch]. The result was folded into this patch so that GDB
still builds at each incremental step.
END_CATCH is necessary for two reasons:
First, because we name the exception object in the CATCH block, which
requires creating a scope, which in turn must be closed somewhere.
Declaring the exception variable in the initializer field of a for
block, like:
#define CATCH(EXCEPTION, mask) \
for (struct gdb_exception EXCEPTION; \
exceptions_state_mc_catch (&EXCEPTION, MASK); \
EXCEPTION = exception_none)
would avoid needing END_CATCH, but alas, in C mode, we build with C90,
which doesn't allow mixed declarations and code.
Second, because when TRY/CATCH are wired to real C++ try/catch, as
long as we need to handle cleanup chains, even if there's no CATCH
block that wants to catch the exception, we need for stop at every
frame in the unwind chain and run cleanups, then rethrow. That will
be done in END_CATCH.
After we require C++, we'll still need TRY/CATCH/END_CATCH until
cleanups are completely phased out -- TRY/CATCH in C++ mode will
save/restore the current cleanup chain, like in C mode, and END_CATCH
catches otherwise uncaugh exceptions, runs cleanups and rethrows, so
that C++ cleanups and exceptions can coexist.
IMO, this still makes the TRY/CATCH code look a bit more like a
newcomer would expect, so IMO worth it even if we weren't considering
C++.
gdb/ChangeLog.
2015-03-07 Pedro Alves <palves@redhat.com>
* common/common-exceptions.c (struct catcher) <exception>: No
longer a pointer to volatile exception. Now an exception value.
<mask>: Delete field.
(exceptions_state_mc_init): Remove all parameters. Adjust.
(exceptions_state_mc): No longer pop the catcher here.
(exceptions_state_mc_catch): New function.
(throw_exception): Adjust.
* common/common-exceptions.h (exceptions_state_mc_init): Remove
all parameters.
(exceptions_state_mc_catch): Declare.
(TRY_CATCH): Rename to ...
(TRY): ... this. Remove EXCEPTION and MASK parameters.
(CATCH, END_CATCH): New.
All callers adjusted.
gdb/gdbserver/ChangeLog:
2015-03-07 Pedro Alves <palves@redhat.com>
Adjust all callers of TRY_CATCH to use TRY/CATCH/END_CATCH
instead.
The only difference between Py_DECREF and Py_XDECREF is that the latter allows passing
in a NULL object, while the former prohibits it. Given that, it's natural to expect
the same from py_decref vs py_xdecref.
gdb/
2013-05-21 Pedro Alves <palves@redhat.com>
* python/py-prettyprint.c (apply_val_pretty_printer): Check
whether PRINTER is NULL before installing a Py_DECREF cleanup.
* python/py-utils.c (py_decref): Don't check for NULL before
calling Py_DECREF.
Wrap/redefine Py_DECREF ourselves, avoiding the need for uses to care
about extra braces due to the fact that Python only started wrapping Py_DECREF
in 'do {} while (0)' after 2.6.
gdb/
2013-05-21 Pedro Alves <palves@redhat.com>
* python/py-utils.c (py_decref): Remove extra braces.
(gdb_pymodule_addobject): Remove extra braces.
* python-internal.h (gdb_Py_DECREF): New static inline function.
(Py_DECREF): Redefine as calling gdb_Py_DECREF.
get_addr_from_python calls out of TRY_CATCH.
(infpy_write_memory, infpy_search_memory): Likewise.
* python/py-utils.c (get_addr_from_python): Return negative
value on error. Use TRY_CATCH.
* python/python-internal.h (get_addr_from_python): Use
CPYCHECKER_NEGATIVE_RESULT_SETS_EXCEPTION.
The strlen in this function looked suspicious, for the function
documents that STR is in the target's charset (what if it is utf-32,
etc.).
On closer inspection, nothing is calling the function, and it's been
that way ever since the function was added.
gdb/
2013-03-06 Pedro Alves <palves@redhat.com>
* python/py-utils.c (target_string_to_unicode): Delete function.
* python/python-internal.h (target_string_to_unicode): Delete
declaration.
Two modifications:
1. The addition of 2013 to the copyright year range for every file;
2. The use of a single year range, instead of potentially multiple
year ranges, as approved by the FSF.
* NEWS: Mention Python 3 support.
* varobj.c (value_get_print_value): Use
python_string_to_target_string.
* python/py-block.c: Use PyVarObject_HEAD_INIT in initialization
of type objects.
* python/py-breakpoint.c: Ditto.
* python/py-cmd.c: Ditto.
* python/py-event.c: Ditto.
* python/py-event.h: Ditto.
* python/py-evtregistry.c: Ditto.
* python/py-finishbreakpoint.c: Ditto.
* python/py-frame.c: Ditto.
* python/py-function.c: Ditto.
* python/py-infthread.c: Ditto.
* python/py-lazy-string.c: Ditto.
* python/py-progspace.c: Ditto.
* /python/py-symbol.c: Ditto.
* python/py-evts.c: (gdbpy_initialize_py_events): Add module
initialization for Python 3.
* python/py-inferior.c: Use PyVarObject_HEAD_INIT in initialization
of type objects.
(infpy_read_memory): Return memoryview object if Python 3.
(infpy_write_memory): Use "s*" operand parsing code for Python 3.
(infpy_search_memory): Ditto.
(get_buffer): New function for Python 3.
* python/py-objfile.c: Use PyVarObject_HEAD_INIT in initialization
of type objects.
(objfpy_dealloc): Use Py_TYPE to call tp_free.
* python/py-param.c: Use PyVarObject_HEAD_INIT in initialization
of type objects.
(get_attr): Use PyUnicode_CompareWithASCIIString if Python 3.
(set_attr): Ditto.
* python/py-prettyprint.c (print_string_repr): use PyBytes methods
instead of PyString methods if Python 3.
(print_children): Skip push_dummy_python_frame call if Python 3.
* python/py-symtab.c: Use PyVarObject_HEAD_INIT in initialization
of type objects.
(salpy_dealloc): Use Py_TYPE to call tp_free.
* python/py-type.c: Use PyVarObject_HEAD_INIT in initialization
of type objects.
(field_dealloc): Use Py_TYPE to call tp_free.
(typy_dealloc): Ditto.
(type_object_as_number): Adjust struct initializations for
differences in layout for Python 2 vs. Python 3.
* python/py-utils.c (python_string_to_unicode): Omit non-Unicode
string case for Python 3.
(unicode_to_encoded_python_string): Shorten code (no functional
change).
(python_string_to_target_python_string): Comment that in Python 3
returned value is a Python "bytes" type.
(gdbpy_is_string): Omit non-Unicode string check in Python 3.
(gdb_py_object_from_longest): Omit non-long integer case in Python
3.
(gdb_py_object_from_ulongest): Ditto.
* python/py-value.c: Use PyVarObject_HEAD_INIT in initialization
of type objects.
(valpy_dealloc): Use Py_TYPE to call tp_free.
(valpy_int): Omit function if Python 3.
(convert_value_from_python): Use "%S" format (Python object as a
string) if Python 3.
(value_object_as_number): Adjust struct initializations for
differences in layout for Python 2 vs. Python 3.
* python/python-config.py: Adjust syntax for Python 3
compatibility.
Include "sys.abiflags" string as part of python library name, if
that attribute exists (Python 3).
* python/python-internal.h (IS_PY3): Define if Python 3.
(Py_TPFLAGS_HAVE_ITER, Py_TPFLAGS_CHECKTYPES): Define with
placeholder value if Python 3.
(PyInt_Check, PyInt_FromLong, PyInt_AsLong, PyString_FromString,
PyString_Decode, PyString_FromFormat, PyString_Check): Define as
analogous Python 3 API function if Python 3.
(PyVarObject_HEAD_INIT): Define if not already defined.
(Py_TYPE): Ditto.
* python/python.c (eval_python_command): Omit Py_FlushLine call if
Python 3.
Check return values of all Python API calls for error.
Supply dummy "python" and "python-interactive" commands if Python
initialization failed.
(_initialize_python): Convert argc to wchar_t** if Python 3.
Add module initialization for Python 3.
(finish_python_initialization): Pass wchar_t * argument to
PySys_SetPath if Python 3.
* python/lib/gdb/__init__.py: Define "reload" if Python 3.
(_GdbFile): New class for common output file behavior.
(GdbOutFile): Subclass from _GdbFile.
(GdbOutputErrorFile): Ditto.
(auto_load_packages): Adjust syntax for Python 3 compatibility.
* python/lib/gdb/printing.py: Define basestr and int if Python 3.
* python/lib/gdb/prompt.py: Use sorted() function rather than
sort() method.
* python/lib/gdb/command/explore.py: Define raw_input if Python 3.
Adjust syntax for Python 3 compatibility.
* python/lib/gdb/command/pretty_printers.py: Use sorted() function
rather than sort() method.
Adjust syntax for Python 3 compatibility.
* python/lib/gdb/command/type_printers.py: Ditto.
* doc/gdb.texinfo (Inferior.read_memory): Mention that the return
value is a memoryview object if Python 3.
* python/py-breakpoint.c: Include python.h.
* python/py-continueevent.c (create_continue_event_object): Make
static.
* python/py-lazy-string.c (stpy_get_type): Make static.
* python/py-newobjfileevent.c (create_new_objfile_event_object):
Make static.
* python/py-utils.c (unicode_to_target_python_string): Make
static.
* python/py-value.c: Include python.h.
* python/py-event.c (event_object_getset): New global.
(event_object_type): Reference it.
* python/py-type.c (field_object_getset): New global.
(field_object_type): Reference it.
* python/python-internal.h (gdb_py_generic_dict): Declare.
* python/py-utils.c (gdb_py_generic_dict): New function.
testsuite/gdb
* gdb.python/py-events.py (exit_handler): Add test for 'dir'.
* gdb.python/py-events.exp: Check 'dir' output.
* gdb.python/py-type.exp (test_fields): Add test for 'dir'.
* NEWS: Document them.
* python/py-cmd.c (cmdpy_function): Don't print a traceback if
the exception is gdb.GdbError. Print a second traceback if there's
an error computing the error message.
(gdbpy_string_to_argv): New function.
* python/py-utils.c (gdbpy_obj_to_string): New function.
(gdbpy_exception_to_string): New function.
* python/python-internal.h (gdbpy_string_to_argv): Declare.
(gdbpy_obj_to_string, gdbpy_exception_to_string): Declare.
(gdbpy_gdberror_exc): Declare.
* python/python.c (gdbpy_gdberror_exc): New global.
(_initialize_python): Initialize gdbpy_gdberror_exc and create
gdb.GdbError.
(GdbMethods): Add string_to_argv.
doc/
* gdb.texinfo (Exception Handling): Document gdb.GdbError.
(Commands In Python): Document gdb.string_to_argv.
testsuite/
* gdb.python/py-cmd.exp: Add tests for gdb.GdbError and
gdb.string_to_argv.
* python/py-auto-load.c: White space.
* python/py-block.c: White space.
* python/py-breakpoint.c: White space.
* python/py-cmd.c: White space.
* python/py-function.c: White space.
* python/py-lazy-string.c: White space.
* python/py-objfile.c: White space.
* python/py-param.c: White space.
* python/py-prettyprint.c: White space.
* python/py-progspace.c: White space.
* python/py-symtab.c: White space.
* python/python.c: White space.
* python/py-type.c: White space.
* python/py-utils.c: White space.
* python/py-value.c: White space.
