binutils-gdb/gdb/python/py-symbol.c
Christian Biesinger 2906593ffe [PR/24474] Add gdb.lookup_static_symbol to the python API
Similar to lookup_global_symbol, except that it checks the
STATIC_SCOPE.

gdb/ChangeLog:

2019-07-30  Christian Biesinger  <cbiesinger@google.com>

	PR/24474: Add a function to lookup static variables.
	* NEWS: Mention this new function.
	* python/py-symbol.c (gdbpy_lookup_static_symbol): New function.
	* python/python-internal.h (gdbpy_lookup_static_symbol): New function.
	* python/python.c (python_GdbMethods): Add new function.

gdb/doc/ChangeLog:

2019-07-30  Christian Biesinger  <cbiesinger@google.com>

	* python.texi (Symbols In Python): Document new function
	gdb.lookup_static_symbol.

gdb/testsuite/ChangeLog:

2019-07-30  Christian Biesinger  <cbiesinger@google.com>

	* gdb.python/py-symbol.c: Add a static variable and one in an anonymous
	namespace.
	* gdb.python/py-symbol.exp: Test gdb.lookup_static_symbol.
2019-07-30 11:04:37 -05:00

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/* Python interface to symbols.
Copyright (C) 2008-2019 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 (const gdb_exception &except)
{
GDB_PY_HANDLE_EXCEPTION (except);
}
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"));
/* TODO: currently, we have no way to recover the block in which SYMBOL
was found, so we have no block to pass to read_var_value. This will
yield an incorrect value when symbol is not local to FRAME_INFO (this
can happen with nested functions). */
value = read_var_value (symbol, NULL, frame_info);
}
catch (const gdb_exception &except)
{
GDB_PY_HANDLE_EXCEPTION (except);
}
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 = ((struct sympy_symbol_object *)
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 const char *keywords[] = { "name", "block", "domain", NULL };
struct symbol *symbol = NULL;
PyObject *block_obj = NULL, *sym_obj, *bool_obj;
const struct block *block = NULL;
if (!gdb_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 (const gdb_exception &except)
{
GDB_PY_HANDLE_EXCEPTION (except);
}
}
try
{
symbol = lookup_symbol (name, block, (domain_enum) domain,
&is_a_field_of_this).symbol;
}
catch (const gdb_exception &except)
{
GDB_PY_HANDLE_EXCEPTION (except);
}
gdbpy_ref<> ret_tuple (PyTuple_New (2));
if (ret_tuple == NULL)
return NULL;
if (symbol)
{
sym_obj = symbol_to_symbol_object (symbol);
if (!sym_obj)
return NULL;
}
else
{
sym_obj = Py_None;
Py_INCREF (Py_None);
}
PyTuple_SET_ITEM (ret_tuple.get (), 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.get (), 1, bool_obj);
return ret_tuple.release ();
}
/* 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 const char *keywords[] = { "name", "domain", NULL };
struct symbol *symbol = NULL;
PyObject *sym_obj;
if (!gdb_PyArg_ParseTupleAndKeywords (args, kw, "s|i", keywords, &name,
&domain))
return NULL;
try
{
symbol = lookup_global_symbol (name, NULL, (domain_enum) domain).symbol;
}
catch (const gdb_exception &except)
{
GDB_PY_HANDLE_EXCEPTION (except);
}
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;
}
/* Implementation of
gdb.lookup_static_symbol (name [, domain) -> symbol or None. */
PyObject *
gdbpy_lookup_static_symbol (PyObject *self, PyObject *args, PyObject *kw)
{
const char *name;
int domain = VAR_DOMAIN;
static const char *keywords[] = { "name", "domain", NULL };
struct symbol *symbol = NULL;
PyObject *sym_obj;
if (!gdb_PyArg_ParseTupleAndKeywords (args, kw, "s|i", keywords, &name,
&domain))
return NULL;
try
{
symbol = lookup_static_symbol (name, (domain_enum) domain).symbol;
}
catch (const gdb_exception &except)
{
GDB_PY_HANDLE_EXCEPTION (except);
}
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 = (symbol_object *) 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_COMMON_BLOCK",
LOC_COMMON_BLOCK) < 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_MODULE_DOMAIN",
MODULE_DOMAIN) < 0
|| PyModule_AddIntConstant (gdb_module, "SYMBOL_COMMON_BLOCK_DOMAIN",
COMMON_BLOCK_DOMAIN) < 0)
return -1;
/* These remain defined for compatibility, but as they were never
correct, they are no longer documented. Eventually we can remove
them. These exist because at one time, enum search_domain and
enum domain_enum_tag were combined -- but different values were
used differently. Here we try to give them values that will make
sense if they are passed to gdb.lookup_symbol. */
if (PyModule_AddIntConstant (gdb_module, "SYMBOL_VARIABLES_DOMAIN",
VAR_DOMAIN) < 0
|| PyModule_AddIntConstant (gdb_module, "SYMBOL_FUNCTIONS_DOMAIN",
VAR_DOMAIN) < 0
|| PyModule_AddIntConstant (gdb_module, "SYMBOL_TYPES_DOMAIN",
VAR_DOMAIN) < 0)
return -1;
return gdb_pymodule_addobject (gdb_module, "Symbol",
(PyObject *) &symbol_object_type);
}
static gdb_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 */
};