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old-cross-binutils/gdb/python/py-framefilter.c
Pedro Alves 492d29ea1c Split TRY_CATCH into TRY + CATCH 
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.
2015-03-07 15:14:14 +00:00

1609 lines
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/* Python frame filters
Copyright (C) 2013-2015 Free Software Foundation, Inc.
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
#include "objfiles.h"
#include "symtab.h"
#include "language.h"
#include "arch-utils.h"
#include "python.h"
#include "ui-out.h"
#include "valprint.h"
#include "annotate.h"
#include "hashtab.h"
#include "demangle.h"
#include "mi/mi-cmds.h"
#include "python-internal.h"
enum mi_print_types
{
MI_PRINT_ARGS,
MI_PRINT_LOCALS
};
/* Helper function to extract a symbol, a name and a language
definition from a Python object that conforms to the "Symbol Value"
interface. OBJ is the Python object to extract the values from.
NAME is a pass-through argument where the name of the symbol will
be written. NAME is allocated in this function, but the caller is
responsible for clean up. SYM is a pass-through argument where the
symbol will be written. In the case of the API returning a string,
this will be set to NULL. LANGUAGE is also a pass-through argument
denoting the language attributed to the Symbol. In the case of SYM
being NULL, this will be set to the current language. Returns
EXT_LANG_BT_ERROR on error with the appropriate Python exception set, and
EXT_LANG_BT_OK on success. */
static enum ext_lang_bt_status
extract_sym (PyObject *obj, char **name, struct symbol **sym,
const struct language_defn **language)
{
PyObject *result = PyObject_CallMethod (obj, "symbol", NULL);
if (result == NULL)
return EXT_LANG_BT_ERROR;
/* For 'symbol' callback, the function can return a symbol or a
string. */
if (gdbpy_is_string (result))
{
*name = python_string_to_host_string (result);
Py_DECREF (result);
if (*name == NULL)
return EXT_LANG_BT_ERROR;
/* If the API returns a string (and not a symbol), then there is
no symbol derived language available and the frame filter has
either overridden the symbol with a string, or supplied a
entirely synthetic symbol/value pairing. In that case, use
python_language. */
*language = python_language;
*sym = NULL;
}
else
{
/* This type checks 'result' during the conversion so we
just call it unconditionally and check the return. */
*sym = symbol_object_to_symbol (result);
Py_DECREF (result);
if (*sym == NULL)
{
PyErr_SetString (PyExc_RuntimeError,
_("Unexpected value. Expecting a "
"gdb.Symbol or a Python string."));
return EXT_LANG_BT_ERROR;
}
/* Duplicate the symbol name, so the caller has consistency
in garbage collection. */
*name = xstrdup (SYMBOL_PRINT_NAME (*sym));
/* If a symbol is specified attempt to determine the language
from the symbol. If mode is not "auto", then the language
has been explicitly set, use that. */
if (language_mode == language_mode_auto)
*language = language_def (SYMBOL_LANGUAGE (*sym));
else
*language = current_language;
}
return EXT_LANG_BT_OK;
}
/* Helper function to extract a value from an object that conforms to
the "Symbol Value" interface. OBJ is the Python object to extract
the value from. VALUE is a pass-through argument where the value
will be written. If the object does not have the value attribute,
or provides the Python None for a value, VALUE will be set to NULL
and this function will return as successful. Returns EXT_LANG_BT_ERROR
on error with the appropriate Python exception set, and EXT_LANG_BT_OK on
success. */
static enum ext_lang_bt_status
extract_value (PyObject *obj, struct value **value)
{
if (PyObject_HasAttrString (obj, "value"))
{
PyObject *vresult = PyObject_CallMethod (obj, "value", NULL);
if (vresult == NULL)
return EXT_LANG_BT_ERROR;
/* The Python code has returned 'None' for a value, so we set
value to NULL. This flags that GDB should read the
value. */
if (vresult == Py_None)
{
Py_DECREF (vresult);
*value = NULL;
return EXT_LANG_BT_OK;
}
else
{
*value = convert_value_from_python (vresult);
Py_DECREF (vresult);
if (*value == NULL)
return EXT_LANG_BT_ERROR;
return EXT_LANG_BT_OK;
}
}
else
*value = NULL;
return EXT_LANG_BT_OK;
}
/* MI prints only certain values according to the type of symbol and
also what the user has specified. SYM is the symbol to check, and
MI_PRINT_TYPES is an enum specifying what the user wants emitted
for the MI command in question. */
static int
mi_should_print (struct symbol *sym, enum mi_print_types type)
{
int print_me = 0;
switch (SYMBOL_CLASS (sym))
{
default:
case LOC_UNDEF: /* catches errors */
case LOC_CONST: /* constant */
case LOC_TYPEDEF: /* local typedef */
case LOC_LABEL: /* local label */
case LOC_BLOCK: /* local function */
case LOC_CONST_BYTES: /* loc. byte seq. */
case LOC_UNRESOLVED: /* unresolved static */
case LOC_OPTIMIZED_OUT: /* optimized out */
print_me = 0;
break;
case LOC_ARG: /* argument */
case LOC_REF_ARG: /* reference arg */
case LOC_REGPARM_ADDR: /* indirect register arg */
case LOC_LOCAL: /* stack local */
case LOC_STATIC: /* static */
case LOC_REGISTER: /* register */
case LOC_COMPUTED: /* computed location */
if (type == MI_PRINT_LOCALS)
print_me = ! SYMBOL_IS_ARGUMENT (sym);
else
print_me = SYMBOL_IS_ARGUMENT (sym);
}
return print_me;
}
/* Helper function which outputs a type name extracted from VAL to a
"type" field in the output stream OUT. OUT is the ui-out structure
the type name will be output too, and VAL is the value that the
type will be extracted from. Returns EXT_LANG_BT_ERROR on error, with
any GDB exceptions converted to a Python exception, or EXT_LANG_BT_OK on
success. */
static enum ext_lang_bt_status
py_print_type (struct ui_out *out, struct value *val)
{
TRY
{
struct type *type;
struct ui_file *stb;
struct cleanup *cleanup;
stb = mem_fileopen ();
cleanup = make_cleanup_ui_file_delete (stb);
type = check_typedef (value_type (val));
type_print (value_type (val), "", stb, -1);
ui_out_field_stream (out, "type", stb);
do_cleanups (cleanup);
}
CATCH (except, RETURN_MASK_ALL)
{
gdbpy_convert_exception (except);
return EXT_LANG_BT_ERROR;
}
END_CATCH
return EXT_LANG_BT_OK;
}
/* Helper function which outputs a value to an output field in a
stream. OUT is the ui-out structure the value will be output to,
VAL is the value that will be printed, OPTS contains the value
printing options, ARGS_TYPE is an enumerator describing the
argument format, and LANGUAGE is the language_defn that the value
will be printed with. Returns EXT_LANG_BT_ERROR on error, with any GDB
exceptions converted to a Python exception, or EXT_LANG_BT_OK on
success. */
static enum ext_lang_bt_status
py_print_value (struct ui_out *out, struct value *val,
const struct value_print_options *opts,
int indent,
enum ext_lang_frame_args args_type,
const struct language_defn *language)
{
int should_print = 0;
int local_indent = (4 * indent);
/* Never set an indent level for common_val_print if MI. */
if (ui_out_is_mi_like_p (out))
local_indent = 0;
/* MI does not print certain values, differentiated by type,
depending on what ARGS_TYPE indicates. Test type against option.
For CLI print all values. */
if (args_type == MI_PRINT_SIMPLE_VALUES
|| args_type == MI_PRINT_ALL_VALUES)
{
struct type *type = NULL;
TRY
{
type = check_typedef (value_type (val));
}
CATCH (except, RETURN_MASK_ALL)
{
gdbpy_convert_exception (except);
return EXT_LANG_BT_ERROR;
}
END_CATCH
if (args_type == MI_PRINT_ALL_VALUES)
should_print = 1;
else if (args_type == MI_PRINT_SIMPLE_VALUES
&& TYPE_CODE (type) != TYPE_CODE_ARRAY
&& TYPE_CODE (type) != TYPE_CODE_STRUCT
&& TYPE_CODE (type) != TYPE_CODE_UNION)
should_print = 1;
}
else if (args_type != NO_VALUES)
should_print = 1;
if (should_print)
{
TRY
{
struct ui_file *stb;
struct cleanup *cleanup;
stb = mem_fileopen ();
cleanup = make_cleanup_ui_file_delete (stb);
common_val_print (val, stb, indent, opts, language);
ui_out_field_stream (out, "value", stb);
do_cleanups (cleanup);
}
CATCH (except, RETURN_MASK_ALL)
{
gdbpy_convert_exception (except);
return EXT_LANG_BT_ERROR;
}
END_CATCH
}
return EXT_LANG_BT_OK;
}
/* Helper function to call a Python method and extract an iterator
from the result. If the function returns anything but an iterator
the exception is preserved and NULL is returned. FILTER is the
Python object to call, and FUNC is the name of the method. Returns
a PyObject, or NULL on error with the appropriate exception set.
This function can return an iterator, or NULL. */
static PyObject *
get_py_iter_from_func (PyObject *filter, char *func)
{
if (PyObject_HasAttrString (filter, func))
{
PyObject *result = PyObject_CallMethod (filter, func, NULL);
if (result != NULL)
{
if (result == Py_None)
{
return result;
}
else
{
PyObject *iterator = PyObject_GetIter (result);
Py_DECREF (result);
return iterator;
}
}
}
else
Py_RETURN_NONE;
return NULL;
}
/* Helper function to output a single frame argument and value to an
output stream. This function will account for entry values if the
FV parameter is populated, the frame argument has entry values
associated with them, and the appropriate "set entry-value"
options are set. Will output in CLI or MI like format depending
on the type of output stream detected. OUT is the output stream,
SYM_NAME is the name of the symbol. If SYM_NAME is populated then
it must have an accompanying value in the parameter FV. FA is a
frame argument structure. If FA is populated, both SYM_NAME and
FV are ignored. OPTS contains the value printing options,
ARGS_TYPE is an enumerator describing the argument format,
PRINT_ARGS_FIELD is a flag which indicates if we output "ARGS=1"
in MI output in commands where both arguments and locals are
printed. Returns EXT_LANG_BT_ERROR on error, with any GDB exceptions
converted to a Python exception, or EXT_LANG_BT_OK on success. */
static enum ext_lang_bt_status
py_print_single_arg (struct ui_out *out,
const char *sym_name,
struct frame_arg *fa,
struct value *fv,
const struct value_print_options *opts,
enum ext_lang_frame_args args_type,
int print_args_field,
const struct language_defn *language)
{
struct value *val;
enum ext_lang_bt_status retval = EXT_LANG_BT_OK;
if (fa != NULL)
{
if (fa->val == NULL && fa->error == NULL)
return EXT_LANG_BT_OK;
language = language_def (SYMBOL_LANGUAGE (fa->sym));
val = fa->val;
}
else
val = fv;
TRY
{
struct cleanup *cleanups = make_cleanup (null_cleanup, NULL);
/* MI has varying rules for tuples, but generally if there is only
one element in each item in the list, do not start a tuple. The
exception is -stack-list-variables which emits an ARGS="1" field
if the value is a frame argument. This is denoted in this
function with PRINT_ARGS_FIELD which is flag from the caller to
emit the ARGS field. */
if (ui_out_is_mi_like_p (out))
{
if (print_args_field || args_type != NO_VALUES)
make_cleanup_ui_out_tuple_begin_end (out, NULL);
}
annotate_arg_begin ();
/* If frame argument is populated, check for entry-values and the
entry value options. */
if (fa != NULL)
{
struct ui_file *stb;
stb = mem_fileopen ();
make_cleanup_ui_file_delete (stb);
fprintf_symbol_filtered (stb, SYMBOL_PRINT_NAME (fa->sym),
SYMBOL_LANGUAGE (fa->sym),
DMGL_PARAMS | DMGL_ANSI);
if (fa->entry_kind == print_entry_values_compact)
{
fputs_filtered ("=", stb);
fprintf_symbol_filtered (stb, SYMBOL_PRINT_NAME (fa->sym),
SYMBOL_LANGUAGE (fa->sym),
DMGL_PARAMS | DMGL_ANSI);
}
if (fa->entry_kind == print_entry_values_only
|| fa->entry_kind == print_entry_values_compact)
{
fputs_filtered ("@entry", stb);
}
ui_out_field_stream (out, "name", stb);
}
else
/* Otherwise, just output the name. */
ui_out_field_string (out, "name", sym_name);
annotate_arg_name_end ();
if (! ui_out_is_mi_like_p (out))
ui_out_text (out, "=");
if (print_args_field)
ui_out_field_int (out, "arg", 1);
/* For MI print the type, but only for simple values. This seems
weird, but this is how MI choose to format the various output
types. */
if (args_type == MI_PRINT_SIMPLE_VALUES && val != NULL)
{
if (py_print_type (out, val) == EXT_LANG_BT_ERROR)
{
retval = EXT_LANG_BT_ERROR;
do_cleanups (cleanups);
continue;
}
}
if (val != NULL)
annotate_arg_value (value_type (val));
/* If the output is to the CLI, and the user option "set print
frame-arguments" is set to none, just output "...". */
if (! ui_out_is_mi_like_p (out) && args_type == NO_VALUES)
ui_out_field_string (out, "value", "...");
else
{
/* Otherwise, print the value for both MI and the CLI, except
for the case of MI_PRINT_NO_VALUES. */
if (args_type != NO_VALUES)
{
if (val == NULL)
{
gdb_assert (fa != NULL && fa->error != NULL);
ui_out_field_fmt (out, "value",
_("<error reading variable: %s>"),
fa->error);
}
else if (py_print_value (out, val, opts, 0, args_type, language)
== EXT_LANG_BT_ERROR)
retval = EXT_LANG_BT_ERROR;
}
}
do_cleanups (cleanups);
}
CATCH (except, RETURN_MASK_ERROR)
{
gdbpy_convert_exception (except);
}
END_CATCH
return retval;
}
/* Helper function to loop over frame arguments provided by the
"frame_arguments" Python API. Elements in the iterator must
conform to the "Symbol Value" interface. ITER is the Python
iterable object, OUT is the output stream, ARGS_TYPE is an
enumerator describing the argument format, PRINT_ARGS_FIELD is a
flag which indicates if we output "ARGS=1" in MI output in commands
where both arguments and locals are printed, and FRAME is the
backing frame. Returns EXT_LANG_BT_ERROR on error, with any GDB
exceptions converted to a Python exception, or EXT_LANG_BT_OK on
success. */
static enum ext_lang_bt_status
enumerate_args (PyObject *iter,
struct ui_out *out,
enum ext_lang_frame_args args_type,
int print_args_field,
struct frame_info *frame)
{
PyObject *item;
struct value_print_options opts;
get_user_print_options (&opts);
if (args_type == CLI_SCALAR_VALUES)
{
/* True in "summary" mode, false otherwise. */
opts.summary = 1;
}
opts.deref_ref = 1;
TRY
{
annotate_frame_args ();
}
CATCH (except, RETURN_MASK_ALL)
{
gdbpy_convert_exception (except);
goto error;
}
END_CATCH
/* Collect the first argument outside of the loop, so output of
commas in the argument output is correct. At the end of the
loop block collect another item from the iterator, and, if it is
not null emit a comma. */
item = PyIter_Next (iter);
if (item == NULL && PyErr_Occurred ())
goto error;
while (item)
{
const struct language_defn *language;
char *sym_name;
struct symbol *sym;
struct value *val;
enum ext_lang_bt_status success = EXT_LANG_BT_ERROR;
success = extract_sym (item, &sym_name, &sym, &language);
if (success == EXT_LANG_BT_ERROR)
{
Py_DECREF (item);
goto error;
}
success = extract_value (item, &val);
if (success == EXT_LANG_BT_ERROR)
{
xfree (sym_name);
Py_DECREF (item);
goto error;
}
Py_DECREF (item);
item = NULL;
if (sym && ui_out_is_mi_like_p (out)
&& ! mi_should_print (sym, MI_PRINT_ARGS))
{
xfree (sym_name);
continue;
}
/* If the object did not provide a value, read it using
read_frame_args and account for entry values, if any. */
if (val == NULL)
{
struct frame_arg arg, entryarg;
/* If there is no value, and also no symbol, set error and
exit. */
if (sym == NULL)
{
PyErr_SetString (PyExc_RuntimeError,
_("No symbol or value provided."));
xfree (sym_name);
goto error;
}
TRY
{
read_frame_arg (sym, frame, &arg, &entryarg);
}
CATCH (except, RETURN_MASK_ALL)
{
xfree (sym_name);
gdbpy_convert_exception (except);
goto error;
}
END_CATCH
/* The object has not provided a value, so this is a frame
argument to be read by GDB. In this case we have to
account for entry-values. */
if (arg.entry_kind != print_entry_values_only)
{
if (py_print_single_arg (out, NULL, &arg,
NULL, &opts,
args_type,
print_args_field,
NULL) == EXT_LANG_BT_ERROR)
{
xfree (arg.error);
xfree (entryarg.error);
xfree (sym_name);
goto error;
}
}
if (entryarg.entry_kind != print_entry_values_no)
{
if (arg.entry_kind != print_entry_values_only)
{
TRY
{
ui_out_text (out, ", ");
ui_out_wrap_hint (out, " ");
}
CATCH (except, RETURN_MASK_ALL)
{
xfree (arg.error);
xfree (entryarg.error);
xfree (sym_name);
gdbpy_convert_exception (except);
goto error;
}
END_CATCH
}
if (py_print_single_arg (out, NULL, &entryarg, NULL, &opts,
args_type, print_args_field, NULL)
== EXT_LANG_BT_ERROR)
{
xfree (arg.error);
xfree (entryarg.error);
xfree (sym_name);
goto error;
}
}
xfree (arg.error);
xfree (entryarg.error);
}
else
{
/* If the object has provided a value, we just print that. */
if (val != NULL)
{
if (py_print_single_arg (out, sym_name, NULL, val, &opts,
args_type, print_args_field,
language) == EXT_LANG_BT_ERROR)
{
xfree (sym_name);
goto error;
}
}
}
xfree (sym_name);
/* Collect the next item from the iterator. If
this is the last item, do not print the
comma. */
item = PyIter_Next (iter);
if (item != NULL)
{
TRY
{
ui_out_text (out, ", ");
}
CATCH (except, RETURN_MASK_ALL)
{
Py_DECREF (item);
gdbpy_convert_exception (except);
goto error;
}
END_CATCH
}
else if (PyErr_Occurred ())
goto error;
TRY
{
annotate_arg_end ();
}
CATCH (except, RETURN_MASK_ALL)
{
Py_DECREF (item);
gdbpy_convert_exception (except);
goto error;
}
END_CATCH
}
return EXT_LANG_BT_OK;
error:
return EXT_LANG_BT_ERROR;
}
/* Helper function to loop over variables provided by the
"frame_locals" Python API. Elements in the iterable must conform
to the "Symbol Value" interface. ITER is the Python iterable
object, OUT is the output stream, INDENT is whether we should
indent the output (for CLI), ARGS_TYPE is an enumerator describing
the argument format, PRINT_ARGS_FIELD is flag which indicates
whether to output the ARGS field in the case of
-stack-list-variables and FRAME is the backing frame. Returns
EXT_LANG_BT_ERROR on error, with any GDB exceptions converted to a Python
exception, or EXT_LANG_BT_OK on success. */
static enum ext_lang_bt_status
enumerate_locals (PyObject *iter,
struct ui_out *out,
int indent,
enum ext_lang_frame_args args_type,
int print_args_field,
struct frame_info *frame)
{
PyObject *item;
struct value_print_options opts;
get_user_print_options (&opts);
opts.deref_ref = 1;
while ((item = PyIter_Next (iter)))
{
const struct language_defn *language;
char *sym_name;
struct value *val;
enum ext_lang_bt_status success = EXT_LANG_BT_ERROR;
struct symbol *sym;
int local_indent = 8 + (8 * indent);
struct cleanup *locals_cleanups;
locals_cleanups = make_cleanup_py_decref (item);
success = extract_sym (item, &sym_name, &sym, &language);
if (success == EXT_LANG_BT_ERROR)
{
do_cleanups (locals_cleanups);
goto error;
}
make_cleanup (xfree, sym_name);
success = extract_value (item, &val);
if (success == EXT_LANG_BT_ERROR)
{
do_cleanups (locals_cleanups);
goto error;
}
if (sym != NULL && ui_out_is_mi_like_p (out)
&& ! mi_should_print (sym, MI_PRINT_LOCALS))
{
do_cleanups (locals_cleanups);
continue;
}
/* If the object did not provide a value, read it. */
if (val == NULL)
{
TRY
{
val = read_var_value (sym, frame);
}
CATCH (except, RETURN_MASK_ERROR)
{
gdbpy_convert_exception (except);
do_cleanups (locals_cleanups);
goto error;
}
END_CATCH
}
/* With PRINT_NO_VALUES, MI does not emit a tuple normally as
each output contains only one field. The exception is
-stack-list-variables, which always provides a tuple. */
if (ui_out_is_mi_like_p (out))
{
if (print_args_field || args_type != NO_VALUES)
make_cleanup_ui_out_tuple_begin_end (out, NULL);
}
TRY
{
if (! ui_out_is_mi_like_p (out))
{
/* If the output is not MI we indent locals. */
ui_out_spaces (out, local_indent);
}
ui_out_field_string (out, "name", sym_name);
if (! ui_out_is_mi_like_p (out))
ui_out_text (out, " = ");
}
CATCH (except, RETURN_MASK_ERROR)
{
gdbpy_convert_exception (except);
do_cleanups (locals_cleanups);
goto error;
}
END_CATCH
if (args_type == MI_PRINT_SIMPLE_VALUES)
{
if (py_print_type (out, val) == EXT_LANG_BT_ERROR)
{
do_cleanups (locals_cleanups);
goto error;
}
}
/* CLI always prints values for locals. MI uses the
simple/no/all system. */
if (! ui_out_is_mi_like_p (out))
{
int val_indent = (indent + 1) * 4;
if (py_print_value (out, val, &opts, val_indent, args_type,
language) == EXT_LANG_BT_ERROR)
{
do_cleanups (locals_cleanups);
goto error;
}
}
else
{
if (args_type != NO_VALUES)
{
if (py_print_value (out, val, &opts, 0, args_type,
language) == EXT_LANG_BT_ERROR)
{
do_cleanups (locals_cleanups);
goto error;
}
}
}
do_cleanups (locals_cleanups);
TRY
{
ui_out_text (out, "\n");
}
CATCH (except, RETURN_MASK_ERROR)
{
gdbpy_convert_exception (except);
goto error;
}
END_CATCH
}
if (item == NULL && PyErr_Occurred ())
goto error;
return EXT_LANG_BT_OK;
error:
return EXT_LANG_BT_ERROR;
}
/* Helper function for -stack-list-variables. Returns EXT_LANG_BT_ERROR on
error, or EXT_LANG_BT_OK on success. */
static enum ext_lang_bt_status
py_mi_print_variables (PyObject *filter, struct ui_out *out,
struct value_print_options *opts,
enum ext_lang_frame_args args_type,
struct frame_info *frame)
{
struct cleanup *old_chain;
PyObject *args_iter;
PyObject *locals_iter;
args_iter = get_py_iter_from_func (filter, "frame_args");
old_chain = make_cleanup_py_xdecref (args_iter);
if (args_iter == NULL)
goto error;
locals_iter = get_py_iter_from_func (filter, "frame_locals");
if (locals_iter == NULL)
goto error;
make_cleanup_py_decref (locals_iter);
make_cleanup_ui_out_list_begin_end (out, "variables");
if (args_iter != Py_None)
if (enumerate_args (args_iter, out, args_type, 1, frame)
== EXT_LANG_BT_ERROR)
goto error;
if (locals_iter != Py_None)
if (enumerate_locals (locals_iter, out, 1, args_type, 1, frame)
== EXT_LANG_BT_ERROR)
goto error;
do_cleanups (old_chain);
return EXT_LANG_BT_OK;
error:
do_cleanups (old_chain);
return EXT_LANG_BT_ERROR;
}
/* Helper function for printing locals. This function largely just
creates the wrapping tuple, and calls enumerate_locals. Returns
EXT_LANG_BT_ERROR on error, or EXT_LANG_BT_OK on success. */
static enum ext_lang_bt_status
py_print_locals (PyObject *filter,
struct ui_out *out,
enum ext_lang_frame_args args_type,
int indent,
struct frame_info *frame)
{
PyObject *locals_iter = get_py_iter_from_func (filter,
"frame_locals");
struct cleanup *old_chain = make_cleanup_py_xdecref (locals_iter);
if (locals_iter == NULL)
goto locals_error;
make_cleanup_ui_out_list_begin_end (out, "locals");
if (locals_iter != Py_None)
if (enumerate_locals (locals_iter, out, indent, args_type,
0, frame) == EXT_LANG_BT_ERROR)
goto locals_error;
do_cleanups (old_chain);
return EXT_LANG_BT_OK;
locals_error:
do_cleanups (old_chain);
return EXT_LANG_BT_ERROR;
}
/* Helper function for printing frame arguments. This function
largely just creates the wrapping tuple, and calls enumerate_args.
Returns EXT_LANG_BT_ERROR on error, with any GDB exceptions converted to
a Python exception, or EXT_LANG_BT_OK on success. */
static enum ext_lang_bt_status
py_print_args (PyObject *filter,
struct ui_out *out,
enum ext_lang_frame_args args_type,
struct frame_info *frame)
{
PyObject *args_iter = get_py_iter_from_func (filter, "frame_args");
struct cleanup *old_chain = make_cleanup_py_xdecref (args_iter);
if (args_iter == NULL)
goto args_error;
make_cleanup_ui_out_list_begin_end (out, "args");
TRY
{
annotate_frame_args ();
if (! ui_out_is_mi_like_p (out))
ui_out_text (out, " (");
}
CATCH (except, RETURN_MASK_ALL)
{
gdbpy_convert_exception (except);
goto args_error;
}
END_CATCH
if (args_iter != Py_None)
if (enumerate_args (args_iter, out, args_type, 0, frame)
== EXT_LANG_BT_ERROR)
goto args_error;
TRY
{
if (! ui_out_is_mi_like_p (out))
ui_out_text (out, ")");
}
CATCH (except, RETURN_MASK_ALL)
{
gdbpy_convert_exception (except);
goto args_error;
}
END_CATCH
do_cleanups (old_chain);
return EXT_LANG_BT_OK;
args_error:
do_cleanups (old_chain);
return EXT_LANG_BT_ERROR;
}
/* Print a single frame to the designated output stream, detecting
whether the output is MI or console, and formatting the output
according to the conventions of that protocol. FILTER is the
frame-filter associated with this frame. FLAGS is an integer
describing the various print options. The FLAGS variables is
described in "apply_frame_filter" function. ARGS_TYPE is an
enumerator describing the argument format. OUT is the output
stream to print, INDENT is the level of indention for this frame
(in the case of elided frames), and LEVELS_PRINTED is a hash-table
containing all the frames level that have already been printed.
If a frame level has been printed, do not print it again (in the
case of elided frames). Returns EXT_LANG_BT_ERROR on error, with any
GDB exceptions converted to a Python exception, or EXT_LANG_BT_COMPLETED
on success. It can also throw an exception RETURN_QUIT. */
static enum ext_lang_bt_status
py_print_frame (PyObject *filter, int flags,
enum ext_lang_frame_args args_type,
struct ui_out *out, int indent, htab_t levels_printed)
{
int has_addr = 0;
CORE_ADDR address = 0;
struct gdbarch *gdbarch = NULL;
struct frame_info *frame = NULL;
struct cleanup *cleanup_stack;
struct value_print_options opts;
PyObject *py_inf_frame;
int print_level, print_frame_info, print_args, print_locals;
/* Extract print settings from FLAGS. */
print_level = (flags & PRINT_LEVEL) ? 1 : 0;
print_frame_info = (flags & PRINT_FRAME_INFO) ? 1 : 0;
print_args = (flags & PRINT_ARGS) ? 1 : 0;
print_locals = (flags & PRINT_LOCALS) ? 1 : 0;
get_user_print_options (&opts);
/* Get the underlying frame. This is needed to determine GDB
architecture, and also, in the cases of frame variables/arguments to
read them if they returned filter object requires us to do so. */
py_inf_frame = PyObject_CallMethod (filter, "inferior_frame", NULL);
if (py_inf_frame == NULL)
return EXT_LANG_BT_ERROR;
frame = frame_object_to_frame_info (py_inf_frame);;
Py_DECREF (py_inf_frame);
if (frame == NULL)
return EXT_LANG_BT_ERROR;
TRY
{
gdbarch = get_frame_arch (frame);
}
CATCH (except, RETURN_MASK_ERROR)
{
gdbpy_convert_exception (except);
return EXT_LANG_BT_ERROR;
}
END_CATCH
/* stack-list-variables. */
if (print_locals && print_args && ! print_frame_info)
{
if (py_mi_print_variables (filter, out, &opts,
args_type, frame) == EXT_LANG_BT_ERROR)
return EXT_LANG_BT_ERROR;
return EXT_LANG_BT_COMPLETED;
}
cleanup_stack = make_cleanup (null_cleanup, NULL);
/* -stack-list-locals does not require a
wrapping frame attribute. */
if (print_frame_info || (print_args && ! print_locals))
make_cleanup_ui_out_tuple_begin_end (out, "frame");
if (print_frame_info)
{
/* Elided frames are also printed with this function (recursively)
and are printed with indention. */
if (indent > 0)
{
TRY
{
ui_out_spaces (out, indent*4);
}
CATCH (except, RETURN_MASK_ERROR)
{
gdbpy_convert_exception (except);
do_cleanups (cleanup_stack);
return EXT_LANG_BT_ERROR;
}
END_CATCH
}
/* The address is required for frame annotations, and also for
address printing. */
if (PyObject_HasAttrString (filter, "address"))
{
PyObject *paddr = PyObject_CallMethod (filter, "address", NULL);
if (paddr == NULL)
{
do_cleanups (cleanup_stack);
return EXT_LANG_BT_ERROR;
}
if (paddr != Py_None)
{
address = PyLong_AsLong (paddr);
has_addr = 1;
}
Py_DECREF (paddr);
}
}
/* Print frame level. MI does not require the level if
locals/variables only are being printed. */
if ((print_frame_info || print_args) && print_level)
{
struct frame_info **slot;
int level;
slot = (struct frame_info **) htab_find_slot (levels_printed,
frame, INSERT);
TRY
{
level = frame_relative_level (frame);
/* Check if this frame has already been printed (there are cases
where elided synthetic dummy-frames have to 'borrow' the frame
architecture from the eliding frame. If that is the case, do
not print 'level', but print spaces. */
if (*slot == frame)
ui_out_field_skip (out, "level");
else
{
*slot = frame;
annotate_frame_begin (print_level ? level : 0,
gdbarch, address);
ui_out_text (out, "#");
ui_out_field_fmt_int (out, 2, ui_left, "level",
level);
}
}
CATCH (except, RETURN_MASK_ERROR)
{
gdbpy_convert_exception (except);
do_cleanups (cleanup_stack);
return EXT_LANG_BT_ERROR;
}
END_CATCH
}
if (print_frame_info)
{
/* Print address to the address field. If an address is not provided,
print nothing. */
if (opts.addressprint && has_addr)
{
TRY
{
annotate_frame_address ();
ui_out_field_core_addr (out, "addr", gdbarch, address);
annotate_frame_address_end ();
ui_out_text (out, " in ");
}
CATCH (except, RETURN_MASK_ERROR)
{
gdbpy_convert_exception (except);
do_cleanups (cleanup_stack);
return EXT_LANG_BT_ERROR;
}
END_CATCH
}
/* Print frame function name. */
if (PyObject_HasAttrString (filter, "function"))
{
PyObject *py_func = PyObject_CallMethod (filter, "function", NULL);
struct cleanup *py_func_cleanup;
const char *function = NULL;
if (py_func == NULL)
{
do_cleanups (cleanup_stack);
return EXT_LANG_BT_ERROR;
}
py_func_cleanup = make_cleanup_py_decref (py_func);
if (gdbpy_is_string (py_func))
{
char *function_to_free;
function = function_to_free =
python_string_to_host_string (py_func);
if (function == NULL)
{
do_cleanups (cleanup_stack);
return EXT_LANG_BT_ERROR;
}
make_cleanup (xfree, function_to_free);
}
else if (PyLong_Check (py_func))
{
CORE_ADDR addr = PyLong_AsUnsignedLongLong (py_func);
struct bound_minimal_symbol msymbol;
if (PyErr_Occurred ())
{
do_cleanups (cleanup_stack);
return EXT_LANG_BT_ERROR;
}
msymbol = lookup_minimal_symbol_by_pc (addr);
if (msymbol.minsym != NULL)
function = MSYMBOL_PRINT_NAME (msymbol.minsym);
}
else if (py_func != Py_None)
{
PyErr_SetString (PyExc_RuntimeError,
_("FrameDecorator.function: expecting a " \
"String, integer or None."));
do_cleanups (cleanup_stack);
return EXT_LANG_BT_ERROR;
}
TRY
{
annotate_frame_function_name ();
if (function == NULL)
ui_out_field_skip (out, "func");
else
ui_out_field_string (out, "func", function);
}
CATCH (except, RETURN_MASK_ERROR)
{
gdbpy_convert_exception (except);
do_cleanups (cleanup_stack);
return EXT_LANG_BT_ERROR;
}
END_CATCH
do_cleanups (py_func_cleanup);
}
}
/* Frame arguments. Check the result, and error if something went
wrong. */
if (print_args)
{
if (py_print_args (filter, out, args_type, frame) == EXT_LANG_BT_ERROR)
{
do_cleanups (cleanup_stack);
return EXT_LANG_BT_ERROR;
}
}
/* File name/source/line number information. */
if (print_frame_info)
{
TRY
{
annotate_frame_source_begin ();
}
CATCH (except, RETURN_MASK_ERROR)
{
gdbpy_convert_exception (except);
do_cleanups (cleanup_stack);
return EXT_LANG_BT_ERROR;
}
END_CATCH
if (PyObject_HasAttrString (filter, "filename"))
{
PyObject *py_fn = PyObject_CallMethod (filter, "filename", NULL);
struct cleanup *py_fn_cleanup;
if (py_fn == NULL)
{
do_cleanups (cleanup_stack);
return EXT_LANG_BT_ERROR;
}
py_fn_cleanup = make_cleanup_py_decref (py_fn);
if (py_fn != Py_None)
{
char *filename = python_string_to_host_string (py_fn);
if (filename == NULL)
{
do_cleanups (cleanup_stack);
return EXT_LANG_BT_ERROR;
}
make_cleanup (xfree, filename);
TRY
{
ui_out_wrap_hint (out, " ");
ui_out_text (out, " at ");
annotate_frame_source_file ();
ui_out_field_string (out, "file", filename);
annotate_frame_source_file_end ();
}
CATCH (except, RETURN_MASK_ERROR)
{
gdbpy_convert_exception (except);
do_cleanups (cleanup_stack);
return EXT_LANG_BT_ERROR;
}
END_CATCH
}
do_cleanups (py_fn_cleanup);
}
if (PyObject_HasAttrString (filter, "line"))
{
PyObject *py_line = PyObject_CallMethod (filter, "line", NULL);
struct cleanup *py_line_cleanup;
int line;
if (py_line == NULL)
{
do_cleanups (cleanup_stack);
return EXT_LANG_BT_ERROR;
}
py_line_cleanup = make_cleanup_py_decref (py_line);
if (py_line != Py_None)
{
line = PyLong_AsLong (py_line);
TRY
{
ui_out_text (out, ":");
annotate_frame_source_line ();
ui_out_field_int (out, "line", line);
}
CATCH (except, RETURN_MASK_ERROR)
{
gdbpy_convert_exception (except);
do_cleanups (cleanup_stack);
return EXT_LANG_BT_ERROR;
}
END_CATCH
}
do_cleanups (py_line_cleanup);
}
}
/* For MI we need to deal with the "children" list population of
elided frames, so if MI output detected do not send newline. */
if (! ui_out_is_mi_like_p (out))
{
TRY
{
annotate_frame_end ();
ui_out_text (out, "\n");
}
CATCH (except, RETURN_MASK_ERROR)
{
gdbpy_convert_exception (except);
do_cleanups (cleanup_stack);
return EXT_LANG_BT_ERROR;
}
END_CATCH
}
if (print_locals)
{
if (py_print_locals (filter, out, args_type, indent,
frame) == EXT_LANG_BT_ERROR)
{
do_cleanups (cleanup_stack);
return EXT_LANG_BT_ERROR;
}
}
{
PyObject *elided;
struct cleanup *elided_cleanup;
/* Finally recursively print elided frames, if any. */
elided = get_py_iter_from_func (filter, "elided");
if (elided == NULL)
{
do_cleanups (cleanup_stack);
return EXT_LANG_BT_ERROR;
}
elided_cleanup = make_cleanup_py_decref (elided);
if (elided != Py_None)
{
PyObject *item;
make_cleanup_ui_out_list_begin_end (out, "children");
if (! ui_out_is_mi_like_p (out))
indent++;
while ((item = PyIter_Next (elided)))
{
struct cleanup *item_cleanup = make_cleanup_py_decref (item);
enum ext_lang_bt_status success = py_print_frame (item, flags,
args_type, out,
indent,
levels_printed);
do_cleanups (item_cleanup);
if (success == EXT_LANG_BT_ERROR)
{
do_cleanups (cleanup_stack);
return EXT_LANG_BT_ERROR;
}
}
if (item == NULL && PyErr_Occurred ())
{
do_cleanups (cleanup_stack);
return EXT_LANG_BT_ERROR;
}
}
do_cleanups (elided_cleanup);
}
do_cleanups (cleanup_stack);
return EXT_LANG_BT_COMPLETED;
}
/* Helper function to initiate frame filter invocation at starting
frame FRAME. */
static PyObject *
bootstrap_python_frame_filters (struct frame_info *frame,
int frame_low, int frame_high)
{
struct cleanup *cleanups =
make_cleanup (null_cleanup, NULL);
PyObject *module, *sort_func, *iterable, *frame_obj, *iterator;
PyObject *py_frame_low, *py_frame_high;
frame_obj = frame_info_to_frame_object (frame);
if (frame_obj == NULL)
goto error;
make_cleanup_py_decref (frame_obj);
module = PyImport_ImportModule ("gdb.frames");
if (module == NULL)
goto error;
make_cleanup_py_decref (module);
sort_func = PyObject_GetAttrString (module, "execute_frame_filters");
if (sort_func == NULL)
goto error;
make_cleanup_py_decref (sort_func);
py_frame_low = PyInt_FromLong (frame_low);
if (py_frame_low == NULL)
goto error;
make_cleanup_py_decref (py_frame_low);
py_frame_high = PyInt_FromLong (frame_high);
if (py_frame_high == NULL)
goto error;
make_cleanup_py_decref (py_frame_high);
iterable = PyObject_CallFunctionObjArgs (sort_func, frame_obj,
py_frame_low,
py_frame_high,
NULL);
if (iterable == NULL)
goto error;
do_cleanups (cleanups);
if (iterable != Py_None)
{
iterator = PyObject_GetIter (iterable);
Py_DECREF (iterable);
}
else
{
return iterable;
}
return iterator;
error:
do_cleanups (cleanups);
return NULL;
}
/* This is the only publicly exported function in this file. FRAME
is the source frame to start frame-filter invocation. FLAGS is an
integer holding the flags for printing. The following elements of
the FRAME_FILTER_FLAGS enum denotes the make-up of FLAGS:
PRINT_LEVEL is a flag indicating whether to print the frame's
relative level in the output. PRINT_FRAME_INFO is a flag that
indicates whether this function should print the frame
information, PRINT_ARGS is a flag that indicates whether to print
frame arguments, and PRINT_LOCALS, likewise, with frame local
variables. ARGS_TYPE is an enumerator describing the argument
format, OUT is the output stream to print. FRAME_LOW is the
beginning of the slice of frames to print, and FRAME_HIGH is the
upper limit of the frames to count. Returns EXT_LANG_BT_ERROR on error,
or EXT_LANG_BT_COMPLETED on success. */
enum ext_lang_bt_status
gdbpy_apply_frame_filter (const struct extension_language_defn *extlang,
struct frame_info *frame, int flags,
enum ext_lang_frame_args args_type,
struct ui_out *out, int frame_low, int frame_high)
{
struct gdbarch *gdbarch = NULL;
struct cleanup *cleanups;
enum ext_lang_bt_status success = EXT_LANG_BT_ERROR;
PyObject *iterable;
PyObject *item;
htab_t levels_printed;
if (!gdb_python_initialized)
return EXT_LANG_BT_NO_FILTERS;
TRY
{
gdbarch = get_frame_arch (frame);
}
CATCH (except, RETURN_MASK_ALL)
{
/* Let gdb try to print the stack trace. */
return EXT_LANG_BT_NO_FILTERS;
}
END_CATCH
cleanups = ensure_python_env (gdbarch, current_language);
iterable = bootstrap_python_frame_filters (frame, frame_low, frame_high);
if (iterable == NULL)
{
/* Normally if there is an error GDB prints the exception,
abandons the backtrace and exits. The user can then call "bt
no-filters", and get a default backtrace (it would be
confusing to automatically start a standard backtrace halfway
through a Python filtered backtrace). However in the case
where GDB cannot initialize the frame filters (most likely
due to incorrect auto-load paths), GDB has printed nothing.
In this case it is OK to print the default backtrace after
printing the error message. GDB returns EXT_LANG_BT_NO_FILTERS
here to signify there are no filters after printing the
initialization error. This return code will trigger a
default backtrace. */
gdbpy_print_stack ();
do_cleanups (cleanups);
return EXT_LANG_BT_NO_FILTERS;
}
/* If iterable is None, then there are no frame filters registered.
If this is the case, defer to default GDB printing routines in MI
and CLI. */
make_cleanup_py_decref (iterable);
if (iterable == Py_None)
{
success = EXT_LANG_BT_NO_FILTERS;
goto done;
}
levels_printed = htab_create (20,
htab_hash_pointer,
htab_eq_pointer,
NULL);
make_cleanup_htab_delete (levels_printed);
while ((item = PyIter_Next (iterable)))
{
struct cleanup *item_cleanup = make_cleanup_py_decref (item);
success = py_print_frame (item, flags, args_type, out, 0,
levels_printed);
do_cleanups (item_cleanup);
/* Do not exit on error printing a single frame. Print the
error and continue with other frames. */
if (success == EXT_LANG_BT_ERROR)
gdbpy_print_stack ();
}
if (item == NULL && PyErr_Occurred ())
goto error;
done:
do_cleanups (cleanups);
return success;
/* Exit and abandon backtrace on error, printing the exception that
is set. */
error:
gdbpy_print_stack ();
do_cleanups (cleanups);
return EXT_LANG_BT_ERROR;
}
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