old-cross-binutils/gdb/python/py-symbol.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

630 lines
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/* Python interface to symbols.
Copyright (C) 2008-2015 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 "block.h"
#include "frame.h"
#include "symtab.h"
#include "python-internal.h"
#include "objfiles.h"
typedef struct sympy_symbol_object {
PyObject_HEAD
/* The GDB symbol structure this object is wrapping. */
struct symbol *symbol;
/* A symbol object is associated with an objfile, so keep track with
doubly-linked list, rooted in the objfile. This lets us
invalidate the underlying struct symbol when the objfile is
deleted. */
struct sympy_symbol_object *prev;
struct sympy_symbol_object *next;
} symbol_object;
/* Require a valid symbol. All access to symbol_object->symbol should be
gated by this call. */
#define SYMPY_REQUIRE_VALID(symbol_obj, symbol) \
do { \
symbol = symbol_object_to_symbol (symbol_obj); \
if (symbol == NULL) \
{ \
PyErr_SetString (PyExc_RuntimeError, \
_("Symbol is invalid.")); \
return NULL; \
} \
} while (0)
static const struct objfile_data *sympy_objfile_data_key;
static PyObject *
sympy_str (PyObject *self)
{
PyObject *result;
struct symbol *symbol = NULL;
SYMPY_REQUIRE_VALID (self, symbol);
result = PyString_FromString (SYMBOL_PRINT_NAME (symbol));
return result;
}
static PyObject *
sympy_get_type (PyObject *self, void *closure)
{
struct symbol *symbol = NULL;
SYMPY_REQUIRE_VALID (self, symbol);
if (SYMBOL_TYPE (symbol) == NULL)
{
Py_INCREF (Py_None);
return Py_None;
}
return type_to_type_object (SYMBOL_TYPE (symbol));
}
static PyObject *
sympy_get_symtab (PyObject *self, void *closure)
{
struct symbol *symbol = NULL;
SYMPY_REQUIRE_VALID (self, symbol);
if (!SYMBOL_OBJFILE_OWNED (symbol))
Py_RETURN_NONE;
return symtab_to_symtab_object (symbol_symtab (symbol));
}
static PyObject *
sympy_get_name (PyObject *self, void *closure)
{
struct symbol *symbol = NULL;
SYMPY_REQUIRE_VALID (self, symbol);
return PyString_FromString (SYMBOL_NATURAL_NAME (symbol));
}
static PyObject *
sympy_get_linkage_name (PyObject *self, void *closure)
{
struct symbol *symbol = NULL;
SYMPY_REQUIRE_VALID (self, symbol);
return PyString_FromString (SYMBOL_LINKAGE_NAME (symbol));
}
static PyObject *
sympy_get_print_name (PyObject *self, void *closure)
{
struct symbol *symbol = NULL;
SYMPY_REQUIRE_VALID (self, symbol);
return sympy_str (self);
}
static PyObject *
sympy_get_addr_class (PyObject *self, void *closure)
{
struct symbol *symbol = NULL;
SYMPY_REQUIRE_VALID (self, symbol);
return PyInt_FromLong (SYMBOL_CLASS (symbol));
}
static PyObject *
sympy_is_argument (PyObject *self, void *closure)
{
struct symbol *symbol = NULL;
SYMPY_REQUIRE_VALID (self, symbol);
return PyBool_FromLong (SYMBOL_IS_ARGUMENT (symbol));
}
static PyObject *
sympy_is_constant (PyObject *self, void *closure)
{
struct symbol *symbol = NULL;
enum address_class theclass;
SYMPY_REQUIRE_VALID (self, symbol);
theclass = SYMBOL_CLASS (symbol);
return PyBool_FromLong (theclass == LOC_CONST || theclass == LOC_CONST_BYTES);
}
static PyObject *
sympy_is_function (PyObject *self, void *closure)
{
struct symbol *symbol = NULL;
enum address_class theclass;
SYMPY_REQUIRE_VALID (self, symbol);
theclass = SYMBOL_CLASS (symbol);
return PyBool_FromLong (theclass == LOC_BLOCK);
}
static PyObject *
sympy_is_variable (PyObject *self, void *closure)
{
struct symbol *symbol = NULL;
enum address_class theclass;
SYMPY_REQUIRE_VALID (self, symbol);
theclass = SYMBOL_CLASS (symbol);
return PyBool_FromLong (!SYMBOL_IS_ARGUMENT (symbol)
&& (theclass == LOC_LOCAL || theclass == LOC_REGISTER
|| theclass == LOC_STATIC || theclass == LOC_COMPUTED
|| theclass == LOC_OPTIMIZED_OUT));
}
/* Implementation of gdb.Symbol.needs_frame -> Boolean.
Returns true iff the symbol needs a frame for evaluation. */
static PyObject *
sympy_needs_frame (PyObject *self, void *closure)
{
struct symbol *symbol = NULL;
int result = 0;
SYMPY_REQUIRE_VALID (self, symbol);
TRY
{
result = symbol_read_needs_frame (symbol);
}
CATCH (except, RETURN_MASK_ALL)
{
GDB_PY_HANDLE_EXCEPTION (except);
}
END_CATCH
if (result)
Py_RETURN_TRUE;
Py_RETURN_FALSE;
}
/* Implementation of gdb.Symbol.line -> int.
Returns the line number at which the symbol was defined. */
static PyObject *
sympy_line (PyObject *self, void *closure)
{
struct symbol *symbol = NULL;
SYMPY_REQUIRE_VALID (self, symbol);
return PyInt_FromLong (SYMBOL_LINE (symbol));
}
/* Implementation of gdb.Symbol.is_valid (self) -> Boolean.
Returns True if this Symbol still exists in GDB. */
static PyObject *
sympy_is_valid (PyObject *self, PyObject *args)
{
struct symbol *symbol = NULL;
symbol = symbol_object_to_symbol (self);
if (symbol == NULL)
Py_RETURN_FALSE;
Py_RETURN_TRUE;
}
/* Implementation of gdb.Symbol.value (self[, frame]) -> gdb.Value. Returns
the value of the symbol, or an error in various circumstances. */
static PyObject *
sympy_value (PyObject *self, PyObject *args)
{
struct symbol *symbol = NULL;
struct frame_info *frame_info = NULL;
PyObject *frame_obj = NULL;
struct value *value = NULL;
if (!PyArg_ParseTuple (args, "|O", &frame_obj))
return NULL;
if (frame_obj != NULL && !PyObject_TypeCheck (frame_obj, &frame_object_type))
{
PyErr_SetString (PyExc_TypeError, "argument is not a frame");
return NULL;
}
SYMPY_REQUIRE_VALID (self, symbol);
if (SYMBOL_CLASS (symbol) == LOC_TYPEDEF)
{
PyErr_SetString (PyExc_TypeError, "cannot get the value of a typedef");
return NULL;
}
TRY
{
if (frame_obj != NULL)
{
frame_info = frame_object_to_frame_info (frame_obj);
if (frame_info == NULL)
error (_("invalid frame"));
}
if (symbol_read_needs_frame (symbol) && frame_info == NULL)
error (_("symbol requires a frame to compute its value"));
value = read_var_value (symbol, frame_info);
}
CATCH (except, RETURN_MASK_ALL)
{
GDB_PY_HANDLE_EXCEPTION (except);
}
END_CATCH
return value_to_value_object (value);
}
/* Given a symbol, and a symbol_object that has previously been
allocated and initialized, populate the symbol_object with the
struct symbol data. Also, register the symbol_object life-cycle
with the life-cycle of the object file associated with this
symbol, if needed. */
static void
set_symbol (symbol_object *obj, struct symbol *symbol)
{
obj->symbol = symbol;
obj->prev = NULL;
if (SYMBOL_OBJFILE_OWNED (symbol)
&& symbol_symtab (symbol) != NULL)
{
struct objfile *objfile = symbol_objfile (symbol);
obj->next = objfile_data (objfile, sympy_objfile_data_key);
if (obj->next)
obj->next->prev = obj;
set_objfile_data (objfile, sympy_objfile_data_key, obj);
}
else
obj->next = NULL;
}
/* Create a new symbol object (gdb.Symbol) that encapsulates the struct
symbol object from GDB. */
PyObject *
symbol_to_symbol_object (struct symbol *sym)
{
symbol_object *sym_obj;
sym_obj = PyObject_New (symbol_object, &symbol_object_type);
if (sym_obj)
set_symbol (sym_obj, sym);
return (PyObject *) sym_obj;
}
/* Return the symbol that is wrapped by this symbol object. */
struct symbol *
symbol_object_to_symbol (PyObject *obj)
{
if (! PyObject_TypeCheck (obj, &symbol_object_type))
return NULL;
return ((symbol_object *) obj)->symbol;
}
static void
sympy_dealloc (PyObject *obj)
{
symbol_object *sym_obj = (symbol_object *) obj;
if (sym_obj->prev)
sym_obj->prev->next = sym_obj->next;
else if (sym_obj->symbol != NULL
&& SYMBOL_OBJFILE_OWNED (sym_obj->symbol)
&& symbol_symtab (sym_obj->symbol) != NULL)
{
set_objfile_data (symbol_objfile (sym_obj->symbol),
sympy_objfile_data_key, sym_obj->next);
}
if (sym_obj->next)
sym_obj->next->prev = sym_obj->prev;
sym_obj->symbol = NULL;
}
/* Implementation of
gdb.lookup_symbol (name [, block] [, domain]) -> (symbol, is_field_of_this)
A tuple with 2 elements is always returned. The first is the symbol
object or None, the second is a boolean with the value of
is_a_field_of_this (see comment in lookup_symbol_in_language). */
PyObject *
gdbpy_lookup_symbol (PyObject *self, PyObject *args, PyObject *kw)
{
int domain = VAR_DOMAIN;
struct field_of_this_result is_a_field_of_this;
const char *name;
static char *keywords[] = { "name", "block", "domain", NULL };
struct symbol *symbol = NULL;
PyObject *block_obj = NULL, *ret_tuple, *sym_obj, *bool_obj;
const struct block *block = NULL;
if (! PyArg_ParseTupleAndKeywords (args, kw, "s|O!i", keywords, &name,
&block_object_type, &block_obj, &domain))
return NULL;
if (block_obj)
block = block_object_to_block (block_obj);
else
{
struct frame_info *selected_frame;
TRY
{
selected_frame = get_selected_frame (_("No frame selected."));
block = get_frame_block (selected_frame, NULL);
}
CATCH (except, RETURN_MASK_ALL)
{
GDB_PY_HANDLE_EXCEPTION (except);
}
END_CATCH
}
TRY
{
symbol = lookup_symbol (name, block, domain, &is_a_field_of_this);
}
CATCH (except, RETURN_MASK_ALL)
{
GDB_PY_HANDLE_EXCEPTION (except);
}
END_CATCH
ret_tuple = PyTuple_New (2);
if (!ret_tuple)
return NULL;
if (symbol)
{
sym_obj = symbol_to_symbol_object (symbol);
if (!sym_obj)
{
Py_DECREF (ret_tuple);
return NULL;
}
}
else
{
sym_obj = Py_None;
Py_INCREF (Py_None);
}
PyTuple_SET_ITEM (ret_tuple, 0, sym_obj);
bool_obj = (is_a_field_of_this.type != NULL) ? Py_True : Py_False;
Py_INCREF (bool_obj);
PyTuple_SET_ITEM (ret_tuple, 1, bool_obj);
return ret_tuple;
}
/* Implementation of
gdb.lookup_global_symbol (name [, domain]) -> symbol or None. */
PyObject *
gdbpy_lookup_global_symbol (PyObject *self, PyObject *args, PyObject *kw)
{
int domain = VAR_DOMAIN;
const char *name;
static char *keywords[] = { "name", "domain", NULL };
struct symbol *symbol = NULL;
PyObject *sym_obj;
if (! PyArg_ParseTupleAndKeywords (args, kw, "s|i", keywords, &name,
&domain))
return NULL;
TRY
{
symbol = lookup_global_symbol (name, NULL, domain);
}
CATCH (except, RETURN_MASK_ALL)
{
GDB_PY_HANDLE_EXCEPTION (except);
}
END_CATCH
if (symbol)
{
sym_obj = symbol_to_symbol_object (symbol);
if (!sym_obj)
return NULL;
}
else
{
sym_obj = Py_None;
Py_INCREF (Py_None);
}
return sym_obj;
}
/* This function is called when an objfile is about to be freed.
Invalidate the symbol as further actions on the symbol would result
in bad data. All access to obj->symbol should be gated by
SYMPY_REQUIRE_VALID which will raise an exception on invalid
symbols. */
static void
del_objfile_symbols (struct objfile *objfile, void *datum)
{
symbol_object *obj = datum;
while (obj)
{
symbol_object *next = obj->next;
obj->symbol = NULL;
obj->next = NULL;
obj->prev = NULL;
obj = next;
}
}
int
gdbpy_initialize_symbols (void)
{
if (PyType_Ready (&symbol_object_type) < 0)
return -1;
/* Register an objfile "free" callback so we can properly
invalidate symbol when an object file that is about to be
deleted. */
sympy_objfile_data_key
= register_objfile_data_with_cleanup (NULL, del_objfile_symbols);
if (PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_UNDEF", LOC_UNDEF) < 0
|| PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_CONST",
LOC_CONST) < 0
|| PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_STATIC",
LOC_STATIC) < 0
|| PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_REGISTER",
LOC_REGISTER) < 0
|| PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_ARG",
LOC_ARG) < 0
|| PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_REF_ARG",
LOC_REF_ARG) < 0
|| PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_LOCAL",
LOC_LOCAL) < 0
|| PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_TYPEDEF",
LOC_TYPEDEF) < 0
|| PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_LABEL",
LOC_LABEL) < 0
|| PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_BLOCK",
LOC_BLOCK) < 0
|| PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_CONST_BYTES",
LOC_CONST_BYTES) < 0
|| PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_UNRESOLVED",
LOC_UNRESOLVED) < 0
|| PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_OPTIMIZED_OUT",
LOC_OPTIMIZED_OUT) < 0
|| PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_COMPUTED",
LOC_COMPUTED) < 0
|| PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_REGPARM_ADDR",
LOC_REGPARM_ADDR) < 0
|| PyModule_AddIntConstant (gdb_module, "SYMBOL_UNDEF_DOMAIN",
UNDEF_DOMAIN) < 0
|| PyModule_AddIntConstant (gdb_module, "SYMBOL_VAR_DOMAIN",
VAR_DOMAIN) < 0
|| PyModule_AddIntConstant (gdb_module, "SYMBOL_STRUCT_DOMAIN",
STRUCT_DOMAIN) < 0
|| PyModule_AddIntConstant (gdb_module, "SYMBOL_LABEL_DOMAIN",
LABEL_DOMAIN) < 0
|| PyModule_AddIntConstant (gdb_module, "SYMBOL_VARIABLES_DOMAIN",
VARIABLES_DOMAIN) < 0
|| PyModule_AddIntConstant (gdb_module, "SYMBOL_FUNCTIONS_DOMAIN",
FUNCTIONS_DOMAIN) < 0
|| PyModule_AddIntConstant (gdb_module, "SYMBOL_TYPES_DOMAIN",
TYPES_DOMAIN) < 0)
return -1;
return gdb_pymodule_addobject (gdb_module, "Symbol",
(PyObject *) &symbol_object_type);
}
static PyGetSetDef symbol_object_getset[] = {
{ "type", sympy_get_type, NULL,
"Type of the symbol.", NULL },
{ "symtab", sympy_get_symtab, NULL,
"Symbol table in which the symbol appears.", NULL },
{ "name", sympy_get_name, NULL,
"Name of the symbol, as it appears in the source code.", NULL },
{ "linkage_name", sympy_get_linkage_name, NULL,
"Name of the symbol, as used by the linker (i.e., may be mangled).",
NULL },
{ "print_name", sympy_get_print_name, NULL,
"Name of the symbol in a form suitable for output.\n\
This is either name or linkage_name, depending on whether the user asked GDB\n\
to display demangled or mangled names.", NULL },
{ "addr_class", sympy_get_addr_class, NULL, "Address class of the symbol." },
{ "is_argument", sympy_is_argument, NULL,
"True if the symbol is an argument of a function." },
{ "is_constant", sympy_is_constant, NULL,
"True if the symbol is a constant." },
{ "is_function", sympy_is_function, NULL,
"True if the symbol is a function or method." },
{ "is_variable", sympy_is_variable, NULL,
"True if the symbol is a variable." },
{ "needs_frame", sympy_needs_frame, NULL,
"True if the symbol requires a frame for evaluation." },
{ "line", sympy_line, NULL,
"The source line number at which the symbol was defined." },
{ NULL } /* Sentinel */
};
static PyMethodDef symbol_object_methods[] = {
{ "is_valid", sympy_is_valid, METH_NOARGS,
"is_valid () -> Boolean.\n\
Return true if this symbol is valid, false if not." },
{ "value", sympy_value, METH_VARARGS,
"value ([frame]) -> gdb.Value\n\
Return the value of the symbol." },
{NULL} /* Sentinel */
};
PyTypeObject symbol_object_type = {
PyVarObject_HEAD_INIT (NULL, 0)
"gdb.Symbol", /*tp_name*/
sizeof (symbol_object), /*tp_basicsize*/
0, /*tp_itemsize*/
sympy_dealloc, /*tp_dealloc*/
0, /*tp_print*/
0, /*tp_getattr*/
0, /*tp_setattr*/
0, /*tp_compare*/
0, /*tp_repr*/
0, /*tp_as_number*/
0, /*tp_as_sequence*/
0, /*tp_as_mapping*/
0, /*tp_hash */
0, /*tp_call*/
sympy_str, /*tp_str*/
0, /*tp_getattro*/
0, /*tp_setattro*/
0, /*tp_as_buffer*/
Py_TPFLAGS_DEFAULT, /*tp_flags*/
"GDB symbol object", /*tp_doc */
0, /*tp_traverse */
0, /*tp_clear */
0, /*tp_richcompare */
0, /*tp_weaklistoffset */
0, /*tp_iter */
0, /*tp_iternext */
symbol_object_methods, /*tp_methods */
0, /*tp_members */
symbol_object_getset /*tp_getset */
};