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cpython/Objects/codeobject.c

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#include "Python.h"
#include "code.h"
#include "structmember.h"
#define NAME_CHARS \
"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz"
/* all_name_chars(s): true iff all chars in s are valid NAME_CHARS */
static int
all_name_chars(PyObject *o)
{
static char ok_name_char[256];
static unsigned char *name_chars = (unsigned char *)NAME_CHARS;
PyUnicodeObject *u = (PyUnicodeObject *)o;
const unsigned char *s;
if (!PyUnicode_Check(o) || PyUnicode_READY(u) == -1 ||
PyUnicode_MAX_CHAR_VALUE(u) >= 128)
return 0;
if (ok_name_char[*name_chars] == 0) {
unsigned char *p;
for (p = name_chars; *p; p++)
ok_name_char[*p] = 1;
}
s = PyUnicode_1BYTE_DATA(u);
while (*s) {
if (ok_name_char[*s++] == 0)
return 0;
}
return 1;
}
static void
intern_strings(PyObject *tuple)
{
Py_ssize_t i;
for (i = PyTuple_GET_SIZE(tuple); --i >= 0; ) {
PyObject *v = PyTuple_GET_ITEM(tuple, i);
if (v == NULL || !PyUnicode_CheckExact(v)) {
Py_FatalError("non-string found in code slot");
}
PyUnicode_InternInPlace(&PyTuple_GET_ITEM(tuple, i));
}
}
PyCodeObject *
PyCode_New(int argcount, int kwonlyargcount,
int nlocals, int stacksize, int flags,
PyObject *code, PyObject *consts, PyObject *names,
PyObject *varnames, PyObject *freevars, PyObject *cellvars,
PyObject *filename, PyObject *name, int firstlineno,
PyObject *lnotab)
{
PyCodeObject *co;
unsigned char *cell2arg = NULL;
Py_ssize_t i, n_cellvars;
/* Check argument types */
if (argcount < 0 || kwonlyargcount < 0 || nlocals < 0 ||
code == NULL ||
consts == NULL || !PyTuple_Check(consts) ||
names == NULL || !PyTuple_Check(names) ||
varnames == NULL || !PyTuple_Check(varnames) ||
freevars == NULL || !PyTuple_Check(freevars) ||
cellvars == NULL || !PyTuple_Check(cellvars) ||
name == NULL || !PyUnicode_Check(name) ||
filename == NULL || !PyUnicode_Check(filename) ||
lnotab == NULL || !PyBytes_Check(lnotab) ||
!PyObject_CheckReadBuffer(code)) {
PyErr_BadInternalCall();
return NULL;
}
/* Ensure that the filename is a ready Unicode string */
if (PyUnicode_READY(filename) < 0)
return NULL;
n_cellvars = PyTuple_GET_SIZE(cellvars);
intern_strings(names);
intern_strings(varnames);
intern_strings(freevars);
intern_strings(cellvars);
/* Intern selected string constants */
for (i = PyTuple_GET_SIZE(consts); --i >= 0; ) {
PyObject *v = PyTuple_GetItem(consts, i);
if (!all_name_chars(v))
continue;
PyUnicode_InternInPlace(&PyTuple_GET_ITEM(consts, i));
}
/* Create mapping between cells and arguments if needed. */
if (n_cellvars) {
Py_ssize_t total_args = argcount + kwonlyargcount +
((flags & CO_VARARGS) != 0) + ((flags & CO_VARKEYWORDS) != 0);
Py_ssize_t alloc_size = sizeof(unsigned char) * n_cellvars;
int used_cell2arg = 0;
cell2arg = PyMem_MALLOC(alloc_size);
if (cell2arg == NULL)
return NULL;
memset(cell2arg, CO_CELL_NOT_AN_ARG, alloc_size);
/* Find cells which are also arguments. */
for (i = 0; i < n_cellvars; i++) {
Py_ssize_t j;
PyObject *cell = PyTuple_GET_ITEM(cellvars, i);
for (j = 0; j < total_args; j++) {
PyObject *arg = PyTuple_GET_ITEM(varnames, j);
if (!PyUnicode_Compare(cell, arg)) {
cell2arg[i] = j;
used_cell2arg = 1;
break;
}
}
}
if (!used_cell2arg) {
PyMem_FREE(cell2arg);
cell2arg = NULL;
}
}
co = PyObject_NEW(PyCodeObject, &PyCode_Type);
if (co == NULL) {
if (cell2arg)
PyMem_FREE(cell2arg);
return NULL;
}
co->co_argcount = argcount;
co->co_kwonlyargcount = kwonlyargcount;
co->co_nlocals = nlocals;
co->co_stacksize = stacksize;
co->co_flags = flags;
Py_INCREF(code);
co->co_code = code;
Py_INCREF(consts);
co->co_consts = consts;
Py_INCREF(names);
co->co_names = names;
Py_INCREF(varnames);
co->co_varnames = varnames;
Py_INCREF(freevars);
co->co_freevars = freevars;
Py_INCREF(cellvars);
co->co_cellvars = cellvars;
co->co_cell2arg = cell2arg;
Py_INCREF(filename);
co->co_filename = filename;
Py_INCREF(name);
co->co_name = name;
co->co_firstlineno = firstlineno;
Py_INCREF(lnotab);
co->co_lnotab = lnotab;
co->co_zombieframe = NULL;
co->co_weakreflist = NULL;
return co;
}
PyCodeObject *
PyCode_NewEmpty(const char *filename, const char *funcname, int firstlineno)
{
static PyObject *emptystring = NULL;
static PyObject *nulltuple = NULL;
PyObject *filename_ob = NULL;
PyObject *funcname_ob = NULL;
PyCodeObject *result = NULL;
if (emptystring == NULL) {
emptystring = PyBytes_FromString("");
if (emptystring == NULL)
goto failed;
}
if (nulltuple == NULL) {
nulltuple = PyTuple_New(0);
if (nulltuple == NULL)
goto failed;
}
funcname_ob = PyUnicode_FromString(funcname);
if (funcname_ob == NULL)
goto failed;
filename_ob = PyUnicode_DecodeFSDefault(filename);
if (filename_ob == NULL)
goto failed;
result = PyCode_New(0, /* argcount */
0, /* kwonlyargcount */
0, /* nlocals */
0, /* stacksize */
0, /* flags */
emptystring, /* code */
nulltuple, /* consts */
nulltuple, /* names */
nulltuple, /* varnames */
nulltuple, /* freevars */
nulltuple, /* cellvars */
filename_ob, /* filename */
funcname_ob, /* name */
firstlineno, /* firstlineno */
emptystring /* lnotab */
);
failed:
Py_XDECREF(funcname_ob);
Py_XDECREF(filename_ob);
return result;
}
#define OFF(x) offsetof(PyCodeObject, x)
static PyMemberDef code_memberlist[] = {
{"co_argcount", T_INT, OFF(co_argcount), READONLY},
{"co_kwonlyargcount", T_INT, OFF(co_kwonlyargcount), READONLY},
{"co_nlocals", T_INT, OFF(co_nlocals), READONLY},
{"co_stacksize",T_INT, OFF(co_stacksize), READONLY},
{"co_flags", T_INT, OFF(co_flags), READONLY},
{"co_code", T_OBJECT, OFF(co_code), READONLY},
{"co_consts", T_OBJECT, OFF(co_consts), READONLY},
{"co_names", T_OBJECT, OFF(co_names), READONLY},
{"co_varnames", T_OBJECT, OFF(co_varnames), READONLY},
{"co_freevars", T_OBJECT, OFF(co_freevars), READONLY},
{"co_cellvars", T_OBJECT, OFF(co_cellvars), READONLY},
{"co_filename", T_OBJECT, OFF(co_filename), READONLY},
{"co_name", T_OBJECT, OFF(co_name), READONLY},
{"co_firstlineno", T_INT, OFF(co_firstlineno), READONLY},
{"co_lnotab", T_OBJECT, OFF(co_lnotab), READONLY},
{NULL} /* Sentinel */
};
/* Helper for code_new: return a shallow copy of a tuple that is
guaranteed to contain exact strings, by converting string subclasses
to exact strings and complaining if a non-string is found. */
static PyObject*
validate_and_copy_tuple(PyObject *tup)
{
PyObject *newtuple;
PyObject *item;
Py_ssize_t i, len;
len = PyTuple_GET_SIZE(tup);
newtuple = PyTuple_New(len);
if (newtuple == NULL)
return NULL;
for (i = 0; i < len; i++) {
item = PyTuple_GET_ITEM(tup, i);
if (PyUnicode_CheckExact(item)) {
Py_INCREF(item);
}
else if (!PyUnicode_Check(item)) {
PyErr_Format(
PyExc_TypeError,
"name tuples must contain only "
"strings, not '%.500s'",
item->ob_type->tp_name);
Py_DECREF(newtuple);
return NULL;
}
else {
item = _PyUnicode_Copy(item);
if (item == NULL) {
Py_DECREF(newtuple);
return NULL;
}
}
PyTuple_SET_ITEM(newtuple, i, item);
}
return newtuple;
}
PyDoc_STRVAR(code_doc,
"code(argcount, kwonlyargcount, nlocals, stacksize, flags, codestring,\n\
constants, names, varnames, filename, name, firstlineno,\n\
lnotab[, freevars[, cellvars]])\n\
\n\
Create a code object. Not for the faint of heart.");
static PyObject *
code_new(PyTypeObject *type, PyObject *args, PyObject *kw)
{
int argcount;
int kwonlyargcount;
int nlocals;
int stacksize;
int flags;
PyObject *co = NULL;
PyObject *code;
PyObject *consts;
PyObject *names, *ournames = NULL;
PyObject *varnames, *ourvarnames = NULL;
PyObject *freevars = NULL, *ourfreevars = NULL;
PyObject *cellvars = NULL, *ourcellvars = NULL;
PyObject *filename;
PyObject *name;
int firstlineno;
PyObject *lnotab;
if (!PyArg_ParseTuple(args, "iiiiiSO!O!O!UUiS|O!O!:code",
&argcount, &kwonlyargcount,
&nlocals, &stacksize, &flags,
&code,
&PyTuple_Type, &consts,
&PyTuple_Type, &names,
&PyTuple_Type, &varnames,
&filename, &name,
&firstlineno, &lnotab,
&PyTuple_Type, &freevars,
&PyTuple_Type, &cellvars))
return NULL;
if (argcount < 0) {
PyErr_SetString(
PyExc_ValueError,
"code: argcount must not be negative");
goto cleanup;
}
if (kwonlyargcount < 0) {
PyErr_SetString(
PyExc_ValueError,
"code: kwonlyargcount must not be negative");
goto cleanup;
}
if (nlocals < 0) {
PyErr_SetString(
PyExc_ValueError,
"code: nlocals must not be negative");
goto cleanup;
}
ournames = validate_and_copy_tuple(names);
if (ournames == NULL)
goto cleanup;
ourvarnames = validate_and_copy_tuple(varnames);
if (ourvarnames == NULL)
goto cleanup;
if (freevars)
ourfreevars = validate_and_copy_tuple(freevars);
else
ourfreevars = PyTuple_New(0);
if (ourfreevars == NULL)
goto cleanup;
if (cellvars)
ourcellvars = validate_and_copy_tuple(cellvars);
else
ourcellvars = PyTuple_New(0);
if (ourcellvars == NULL)
goto cleanup;
co = (PyObject *)PyCode_New(argcount, kwonlyargcount,
nlocals, stacksize, flags,
code, consts, ournames, ourvarnames,
ourfreevars, ourcellvars, filename,
name, firstlineno, lnotab);
cleanup:
Py_XDECREF(ournames);
Py_XDECREF(ourvarnames);
Py_XDECREF(ourfreevars);
Py_XDECREF(ourcellvars);
return co;
}
static void
code_dealloc(PyCodeObject *co)
{
Py_XDECREF(co->co_code);
Py_XDECREF(co->co_consts);
Py_XDECREF(co->co_names);
Py_XDECREF(co->co_varnames);
Py_XDECREF(co->co_freevars);
Py_XDECREF(co->co_cellvars);
Py_XDECREF(co->co_filename);
Py_XDECREF(co->co_name);
Py_XDECREF(co->co_lnotab);
if (co->co_cell2arg != NULL)
PyMem_FREE(co->co_cell2arg);
if (co->co_zombieframe != NULL)
PyObject_GC_Del(co->co_zombieframe);
if (co->co_weakreflist != NULL)
PyObject_ClearWeakRefs((PyObject*)co);
PyObject_DEL(co);
}
static PyObject *
code_sizeof(PyCodeObject *co, void *unused)
{
Py_ssize_t res;
res = _PyObject_SIZE(Py_TYPE(co));
if (co->co_cell2arg != NULL && co->co_cellvars != NULL)
res += PyTuple_GET_SIZE(co->co_cellvars) * sizeof(unsigned char);
return PyLong_FromSsize_t(res);
}
static PyObject *
code_repr(PyCodeObject *co)
{
int lineno;
if (co->co_firstlineno != 0)
lineno = co->co_firstlineno;
else
lineno = -1;
if (co->co_filename && PyUnicode_Check(co->co_filename)) {
return PyUnicode_FromFormat(
"<code object %U at %p, file \"%U\", line %d>",
co->co_name, co, co->co_filename, lineno);
} else {
return PyUnicode_FromFormat(
"<code object %U at %p, file ???, line %d>",
co->co_name, co, lineno);
}
}
PyObject*
_PyCode_ConstantKey(PyObject *op)
{
PyObject *key;
/* Py_None and Py_Ellipsis are singleton */
if (op == Py_None || op == Py_Ellipsis
|| PyLong_CheckExact(op)
|| PyBool_Check(op)
|| PyBytes_CheckExact(op)
|| PyUnicode_CheckExact(op)
/* code_richcompare() uses _PyCode_ConstantKey() internally */
|| PyCode_Check(op)) {
key = PyTuple_Pack(2, Py_TYPE(op), op);
}
else if (PyFloat_CheckExact(op)) {
double d = PyFloat_AS_DOUBLE(op);
/* all we need is to make the tuple different in either the 0.0
* or -0.0 case from all others, just to avoid the "coercion".
*/
if (d == 0.0 && copysign(1.0, d) < 0.0)
key = PyTuple_Pack(3, Py_TYPE(op), op, Py_None);
else
key = PyTuple_Pack(2, Py_TYPE(op), op);
}
else if (PyComplex_CheckExact(op)) {
Py_complex z;
int real_negzero, imag_negzero;
/* For the complex case we must make complex(x, 0.)
different from complex(x, -0.) and complex(0., y)
different from complex(-0., y), for any x and y.
All four complex zeros must be distinguished.*/
z = PyComplex_AsCComplex(op);
real_negzero = z.real == 0.0 && copysign(1.0, z.real) < 0.0;
imag_negzero = z.imag == 0.0 && copysign(1.0, z.imag) < 0.0;
/* use True, False and None singleton as tags for the real and imag
* sign, to make tuples different */
if (real_negzero && imag_negzero) {
key = PyTuple_Pack(3, Py_TYPE(op), op, Py_True);
}
else if (imag_negzero) {
key = PyTuple_Pack(3, Py_TYPE(op), op, Py_False);
}
else if (real_negzero) {
key = PyTuple_Pack(3, Py_TYPE(op), op, Py_None);
}
else {
key = PyTuple_Pack(2, Py_TYPE(op), op);
}
}
else if (PyTuple_CheckExact(op)) {
Py_ssize_t i, len;
PyObject *tuple;
len = PyTuple_GET_SIZE(op);
tuple = PyTuple_New(len);
if (tuple == NULL)
return NULL;
for (i=0; i < len; i++) {
PyObject *item, *item_key;
item = PyTuple_GET_ITEM(op, i);
item_key = _PyCode_ConstantKey(item);
if (item_key == NULL) {
Py_DECREF(tuple);
return NULL;
}
PyTuple_SET_ITEM(tuple, i, item_key);
}
key = PyTuple_Pack(3, Py_TYPE(op), op, tuple);
Py_DECREF(tuple);
}
else if (PyFrozenSet_CheckExact(op)) {
Py_ssize_t pos = 0;
PyObject *item;
Py_hash_t hash;
Py_ssize_t i, len;
PyObject *tuple, *set;
len = PySet_GET_SIZE(op);
tuple = PyTuple_New(len);
if (tuple == NULL)
return NULL;
i = 0;
while (_PySet_NextEntry(op, &pos, &item, &hash)) {
PyObject *item_key;
item_key = _PyCode_ConstantKey(item);
if (item_key == NULL) {
Py_DECREF(tuple);
return NULL;
}
assert(i < len);
PyTuple_SET_ITEM(tuple, i, item_key);
i++;
}
set = PyFrozenSet_New(tuple);
Py_DECREF(tuple);
if (set == NULL)
return NULL;
key = PyTuple_Pack(3, Py_TYPE(op), op, set);
Py_DECREF(set);
return key;
}
else {
/* for other types, use the object identifier as a unique identifier
* to ensure that they are seen as unequal. */
PyObject *obj_id = PyLong_FromVoidPtr(op);
if (obj_id == NULL)
return NULL;
key = PyTuple_Pack(3, Py_TYPE(op), op, obj_id);
Py_DECREF(obj_id);
}
return key;
}
static PyObject *
code_richcompare(PyObject *self, PyObject *other, int op)
{
PyCodeObject *co, *cp;
int eq;
PyObject *consts1, *consts2;
PyObject *res;
if ((op != Py_EQ && op != Py_NE) ||
!PyCode_Check(self) ||
!PyCode_Check(other)) {
Py_RETURN_NOTIMPLEMENTED;
}
co = (PyCodeObject *)self;
cp = (PyCodeObject *)other;
eq = PyObject_RichCompareBool(co->co_name, cp->co_name, Py_EQ);
if (eq <= 0) goto unequal;
eq = co->co_argcount == cp->co_argcount;
if (!eq) goto unequal;
eq = co->co_kwonlyargcount == cp->co_kwonlyargcount;
if (!eq) goto unequal;
eq = co->co_nlocals == cp->co_nlocals;
if (!eq) goto unequal;
eq = co->co_flags == cp->co_flags;
if (!eq) goto unequal;
eq = co->co_firstlineno == cp->co_firstlineno;
if (!eq) goto unequal;
eq = PyObject_RichCompareBool(co->co_code, cp->co_code, Py_EQ);
if (eq <= 0) goto unequal;
/* compare constants */
consts1 = _PyCode_ConstantKey(co->co_consts);
if (!consts1)
return NULL;
consts2 = _PyCode_ConstantKey(cp->co_consts);
if (!consts2) {
Py_DECREF(consts1);
return NULL;
}
eq = PyObject_RichCompareBool(consts1, consts2, Py_EQ);
Py_DECREF(consts1);
Py_DECREF(consts2);
if (eq <= 0) goto unequal;
eq = PyObject_RichCompareBool(co->co_names, cp->co_names, Py_EQ);
if (eq <= 0) goto unequal;
eq = PyObject_RichCompareBool(co->co_varnames, cp->co_varnames, Py_EQ);
if (eq <= 0) goto unequal;
eq = PyObject_RichCompareBool(co->co_freevars, cp->co_freevars, Py_EQ);
if (eq <= 0) goto unequal;
eq = PyObject_RichCompareBool(co->co_cellvars, cp->co_cellvars, Py_EQ);
if (eq <= 0) goto unequal;
if (op == Py_EQ)
res = Py_True;
else
res = Py_False;
goto done;
unequal:
if (eq < 0)
return NULL;
if (op == Py_NE)
res = Py_True;
else
res = Py_False;
done:
Py_INCREF(res);
return res;
}
static Py_hash_t
code_hash(PyCodeObject *co)
{
Py_hash_t h, h0, h1, h2, h3, h4, h5, h6;
h0 = PyObject_Hash(co->co_name);
if (h0 == -1) return -1;
h1 = PyObject_Hash(co->co_code);
if (h1 == -1) return -1;
h2 = PyObject_Hash(co->co_consts);
if (h2 == -1) return -1;
h3 = PyObject_Hash(co->co_names);
if (h3 == -1) return -1;
h4 = PyObject_Hash(co->co_varnames);
if (h4 == -1) return -1;
h5 = PyObject_Hash(co->co_freevars);
if (h5 == -1) return -1;
h6 = PyObject_Hash(co->co_cellvars);
if (h6 == -1) return -1;
h = h0 ^ h1 ^ h2 ^ h3 ^ h4 ^ h5 ^ h6 ^
co->co_argcount ^ co->co_kwonlyargcount ^
co->co_nlocals ^ co->co_flags;
if (h == -1) h = -2;
return h;
}
/* XXX code objects need to participate in GC? */
static struct PyMethodDef code_methods[] = {
{"__sizeof__", (PyCFunction)code_sizeof, METH_NOARGS},
{NULL, NULL} /* sentinel */
};
PyTypeObject PyCode_Type = {
PyVarObject_HEAD_INIT(&PyType_Type, 0)
"code",
sizeof(PyCodeObject),
0,
(destructor)code_dealloc, /* tp_dealloc */
0, /* tp_print */
0, /* tp_getattr */
0, /* tp_setattr */
0, /* tp_reserved */
(reprfunc)code_repr, /* tp_repr */
0, /* tp_as_number */
0, /* tp_as_sequence */
0, /* tp_as_mapping */
(hashfunc)code_hash, /* tp_hash */
0, /* tp_call */
0, /* tp_str */
PyObject_GenericGetAttr, /* tp_getattro */
0, /* tp_setattro */
0, /* tp_as_buffer */
Py_TPFLAGS_DEFAULT, /* tp_flags */
code_doc, /* tp_doc */
0, /* tp_traverse */
0, /* tp_clear */
code_richcompare, /* tp_richcompare */
offsetof(PyCodeObject, co_weakreflist), /* tp_weaklistoffset */
0, /* tp_iter */
0, /* tp_iternext */
code_methods, /* tp_methods */
code_memberlist, /* tp_members */
0, /* tp_getset */
0, /* tp_base */
0, /* tp_dict */
0, /* tp_descr_get */
0, /* tp_descr_set */
0, /* tp_dictoffset */
0, /* tp_init */
0, /* tp_alloc */
code_new, /* tp_new */
};
/* Use co_lnotab to compute the line number from a bytecode index, addrq. See
lnotab_notes.txt for the details of the lnotab representation.
*/
int
PyCode_Addr2Line(PyCodeObject *co, int addrq)
{
Py_ssize_t size = PyBytes_Size(co->co_lnotab) / 2;
unsigned char *p = (unsigned char*)PyBytes_AsString(co->co_lnotab);
int line = co->co_firstlineno;
int addr = 0;
while (--size >= 0) {
addr += *p++;
if (addr > addrq)
break;
line += (signed char)*p;
p++;
}
return line;
}
/* Update *bounds to describe the first and one-past-the-last instructions in
the same line as lasti. Return the number of that line. */
int
_PyCode_CheckLineNumber(PyCodeObject* co, int lasti, PyAddrPair *bounds)
{
Py_ssize_t size;
int addr, line;
unsigned char* p;
p = (unsigned char*)PyBytes_AS_STRING(co->co_lnotab);
size = PyBytes_GET_SIZE(co->co_lnotab) / 2;
addr = 0;
line = co->co_firstlineno;
assert(line > 0);
/* possible optimization: if f->f_lasti == instr_ub
(likely to be a common case) then we already know
instr_lb -- if we stored the matching value of p
somwhere we could skip the first while loop. */
/* See lnotab_notes.txt for the description of
co_lnotab. A point to remember: increments to p
come in (addr, line) pairs. */
bounds->ap_lower = 0;
while (size > 0) {
if (addr + *p > lasti)
break;
addr += *p++;
if ((signed char)*p)
bounds->ap_lower = addr;
line += (signed char)*p;
p++;
--size;
}
if (size > 0) {
while (--size >= 0) {
addr += *p++;
if ((signed char)*p)
break;
p++;
}
bounds->ap_upper = addr;
}
else {
bounds->ap_upper = INT_MAX;
}
return line;
}
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