/pypy/interpreter/pycode.py

"""
Python-style code objects.
PyCode instances have the same co_xxx arguments as CPython code objects.
The bytecode interpreter itself is implemented by the PyFrame class.
"""

import dis, imp, struct, types, new, sys, os

from pypy.interpreter import eval
from pypy.interpreter.signature import Signature
from pypy.interpreter.error import OperationError, oefmt
from pypy.interpreter.gateway import unwrap_spec
from pypy.interpreter.astcompiler.consts import (
    CO_OPTIMIZED, CO_NEWLOCALS, CO_VARARGS, CO_VARKEYWORDS, CO_NESTED,
    CO_GENERATOR, CO_KILL_DOCSTRING, CO_YIELD_INSIDE_TRY)
from pypy.tool.stdlib_opcode import opcodedesc, HAVE_ARGUMENT
from rpython.rlib.rarithmetic import intmask, r_longlong
from rpython.rlib.objectmodel import compute_hash
from rpython.rlib import jit
from rpython.rlib.debug import debug_start, debug_stop, debug_print


class BytecodeCorruption(Exception):
    """Detected bytecode corruption.  Never caught; it's an error."""

# helper

def unpack_str_tuple(space,w_str_tuple):
    return [space.str_w(w_el) for w_el in space.unpackiterable(w_str_tuple)]


# Magic numbers for the bytecode version in code objects.
# See comments in pypy/module/imp/importing.
cpython_magic, = struct.unpack("<i", imp.get_magic())   # host magic number
default_magic = (0xf303 + 7) | 0x0a0d0000               # this PyPy's magic
                                                        # (from CPython 2.7.0)

# cpython_code_signature helper
def cpython_code_signature(code):
    "([list-of-arg-names], vararg-name-or-None, kwarg-name-or-None)."
    argcount = code.co_argcount
    varnames = code.co_varnames
    assert argcount >= 0     # annotator hint
    argnames = list(varnames[:argcount])
    if code.co_flags & CO_VARARGS:
        varargname = varnames[argcount]
        argcount += 1
    else:
        varargname = None
    kwargname = varnames[argcount] if code.co_flags & CO_VARKEYWORDS else None
    return Signature(argnames, varargname, kwargname)

class CodeHookCache(object):
    def __init__(self, space):
        self._code_hook = None

class PyCode(eval.Code):
    "CPython-style code objects."
    _immutable_fields_ = ["_signature", "co_argcount", "co_cellvars[*]",
                          "co_code", "co_consts_w[*]", "co_filename",
                          "co_firstlineno", "co_flags", "co_freevars[*]",
                          "co_lnotab", "co_names_w[*]", "co_nlocals",
                          "co_stacksize", "co_varnames[*]",
                          "_args_as_cellvars[*]", "w_globals?"]

    def __init__(self, space,  argcount, nlocals, stacksize, flags,
                     code, consts, names, varnames, filename,
                     name, firstlineno, lnotab, freevars, cellvars,
                     hidden_applevel=False, magic=default_magic):
        """Initialize a new code object from parameters given by
        the pypy compiler"""
        self.space = space
        eval.Code.__init__(self, name)
        assert nlocals >= 0
        self.co_argcount = argcount
        self.co_nlocals = nlocals
        self.co_stacksize = stacksize
        self.co_flags = flags
        self.co_code = code
        self.co_consts_w = consts
        self.co_names_w = [space.new_interned_str(aname) for aname in names]
        self.co_varnames = varnames
        self.co_freevars = freevars
        self.co_cellvars = cellvars
        self.co_filename = filename
        self.co_name = name
        self.co_firstlineno = firstlineno
        self.co_lnotab = lnotab
        # store the first globals object that the code object is run in in
        # here. if a frame is run in that globals object, it does not need to
        # store it at all
        self.w_globals = None
        self.hidden_applevel = hidden_applevel
        self.magic = magic
        self._signature = cpython_code_signature(self)
        self._initialize()
        self._init_ready()
        self.new_code_hook()

    def frame_stores_global(self, w_globals):
        if self.w_globals is None:
            self.w_globals = w_globals
            return False
        if self.w_globals is w_globals:
            return False
        return True

    def new_code_hook(self):
        code_hook = self.space.fromcache(CodeHookCache)._code_hook
        if code_hook is not None:
            try:
                self.space.call_function(code_hook, self)
            except OperationError as e:
                e.write_unraisable(self.space, "new_code_hook()")

    def _initialize(self):
        from pypy.objspace.std.mapdict import init_mapdict_cache
        if self.co_cellvars:
            argcount = self.co_argcount
            assert argcount >= 0     # annotator hint
            if self.co_flags & CO_VARARGS:
                argcount += 1
            if self.co_flags & CO_VARKEYWORDS:
                argcount += 1
            # Cell vars could shadow already-set arguments.
            # The compiler used to be clever about the order of
            # the variables in both co_varnames and co_cellvars, but
            # it no longer is for the sake of simplicity.  Moreover
            # code objects loaded from CPython don't necessarily follow
            # an order, which could lead to strange bugs if .pyc files
            # produced by CPython are loaded by PyPy.  Note that CPython
            # contains the following bad-looking nested loops at *every*
            # function call!

            # Precompute what arguments need to be copied into cellvars
            args_as_cellvars = []
            argvars = self.co_varnames
            cellvars = self.co_cellvars
            for i in range(len(cellvars)):
                cellname = cellvars[i]
                for j in range(argcount):
                    if cellname == argvars[j]:
                        # argument j has the same name as the cell var i
                        while len(args_as_cellvars) <= i:
                            args_as_cellvars.append(-1)   # pad
                        args_as_cellvars[i] = j
            self._args_as_cellvars = args_as_cellvars[:]
        else:
            self._args_as_cellvars = []

        self._compute_flatcall()

        init_mapdict_cache(self)

    def _init_ready(self):
        "This is a hook for the vmprof module, which overrides this method."

    def _cleanup_(self):
        if (self.magic == cpython_magic and
            '__pypy__' not in sys.builtin_module_names):
            raise Exception("CPython host codes should not be rendered")
        # When translating PyPy, freeze the file name
        #     <builtin>/lastdirname/basename.py
        # instead of freezing the complete translation-time path.
        filename = self.co_filename
        if filename.startswith('<builtin>'):
            return
        filename = filename.lstrip('<').rstrip('>')
        if filename.lower().endswith('.pyc'):
            filename = filename[:-1]
        basename = os.path.basename(filename)
        lastdirname = os.path.basename(os.path.dirname(filename))
        if lastdirname:
            basename = '%s/%s' % (lastdirname, basename)
        self.co_filename = '<builtin>/%s' % (basename,)

    co_names = property(lambda self: [self.space.unwrap(w_name) for w_name in self.co_names_w]) # for trace

    def signature(self):
        return self._signature

    @classmethod
    def _from_code(cls, space, code, hidden_applevel=False, code_hook=None):
        """
        Hack to initialize the code object from a real (CPython) one.
        """
        assert isinstance(code, types.CodeType)
        newconsts_w = [None] * len(code.co_consts)
        num = 0
        if code_hook is None:
            code_hook = cls._from_code
        for const in code.co_consts:
            if isinstance(const, types.CodeType): # from stable compiler
                const = code_hook(space, const, hidden_applevel, code_hook)
            newconsts_w[num] = space.wrap(const)
            num += 1
        # stick the underlying CPython magic value, if the code object
        # comes from there
        return cls(space, code.co_argcount,
                      code.co_nlocals,
                      code.co_stacksize,
                      code.co_flags,
                      code.co_code,
                      newconsts_w[:],
                      list(code.co_names),
                      list(code.co_varnames),
                      code.co_filename,
                      code.co_name,
                      code.co_firstlineno,
                      code.co_lnotab,
                      list(code.co_freevars),
                      list(code.co_cellvars),
                      hidden_applevel, cpython_magic)

    def _compute_flatcall(self):
        # Speed hack!
        self.fast_natural_arity = eval.Code.HOPELESS
        if self.co_flags & (CO_VARARGS | CO_VARKEYWORDS):
            return
        if len(self._args_as_cellvars) > 0:
            return
        if self.co_argcount > 0xff:
            return

        self.fast_natural_arity = eval.Code.FLATPYCALL | self.co_argcount

    def funcrun(self, func, args):
        frame = self.space.createframe(self, func.w_func_globals,
                                  func)
        sig = self._signature
        # speed hack
        fresh_frame = jit.hint(frame, access_directly=True,
                                      fresh_virtualizable=True)
        args.parse_into_scope(None, fresh_frame.locals_cells_stack_w, func.name,
                              sig, func.defs_w)
        fresh_frame.init_cells()
        return frame.run()

    def funcrun_obj(self, func, w_obj, args):
        frame = self.space.createframe(self, func.w_func_globals,
                                  func)
        sig = self._signature
        # speed hack
        fresh_frame = jit.hint(frame, access_directly=True,
                                      fresh_virtualizable=True)
        args.parse_into_scope(w_obj, fresh_frame.locals_cells_stack_w, func.name,
                              sig, func.defs_w)
        fresh_frame.init_cells()
        return frame.run()

    def getvarnames(self):
        return self.co_varnames

    def getdocstring(self, space):
        if self.co_consts_w:   # it is probably never empty
            w_first = self.co_consts_w[0]
            if space.isinstance_w(w_first, space.w_basestring):
                return w_first
        return space.w_None

    def remove_docstrings(self, space):
        if self.co_flags & CO_KILL_DOCSTRING:
            self.co_consts_w[0] = space.w_None
        for w_co in self.co_consts_w:
            if isinstance(w_co, PyCode):
                w_co.remove_docstrings(space)

    def _to_code(self):
        """For debugging only."""
        consts = [None] * len(self.co_consts_w)
        num = 0
        for w in self.co_consts_w:
            if isinstance(w, PyCode):
                consts[num] = w._to_code()
            else:
                consts[num] = self.space.unwrap(w)
            num += 1
        return new.code(self.co_argcount,
                        self.co_nlocals,
                        self.co_stacksize,
                        self.co_flags,
                        self.co_code,
                        tuple(consts),
                        tuple(self.co_names),
                        tuple(self.co_varnames),
                        self.co_filename,
                        self.co_name,
                        self.co_firstlineno,
                        self.co_lnotab,
                        tuple(self.co_freevars),
                        tuple(self.co_cellvars))

    def exec_host_bytecode(self, w_globals, w_locals):
        if sys.version_info < (2, 7):
            raise Exception("PyPy no longer supports Python 2.6 or lower")
        frame = self.space.FrameClass(self.space, self, w_globals, None)
        frame.setdictscope(w_locals)
        return frame.run()

    def dump(self):
        """A dis.dis() dump of the code object."""
        co = self._to_code()
        dis.dis(co)

    def fget_co_consts(self, space):
        return space.newtuple(self.co_consts_w)

    def fget_co_names(self, space):
        return space.newtuple(self.co_names_w)

    def fget_co_varnames(self, space):
        return space.newtuple([space.wrap(name) for name in self.co_varnames])

    def fget_co_cellvars(self, space):
        return space.newtuple([space.wrap(name) for name in self.co_cellvars])

    def fget_co_freevars(self, space):
        return space.newtuple([space.wrap(name) for name in self.co_freevars])

    def descr_code__eq__(self, w_other):
        space = self.space
        if not isinstance(w_other, PyCode):
            return space.w_False
        areEqual = (self.co_name == w_other.co_name and
                    self.co_argcount == w_other.co_argcount and
                    self.co_nlocals == w_other.co_nlocals and
                    self.co_flags == w_other.co_flags and
                    self.co_firstlineno == w_other.co_firstlineno and
                    self.co_code == w_other.co_code and
                    len(self.co_consts_w) == len(w_other.co_consts_w) and
                    len(self.co_names_w) == len(w_other.co_names_w) and
                    self.co_varnames == w_other.co_varnames and
                    self.co_freevars == w_other.co_freevars and
                    self.co_cellvars == w_other.co_cellvars)
        if not areEqual:
            return space.w_False

        for i in range(len(self.co_names_w)):
            if not space.eq_w(self.co_names_w[i], w_other.co_names_w[i]):
                return space.w_False

        for i in range(len(self.co_consts_w)):
            if not space.eq_w(self.co_consts_w[i], w_other.co_consts_w[i]):
                return space.w_False

        return space.w_True

    def descr_code__hash__(self):
        space = self.space
        result =  compute_hash(self.co_name)
        result ^= self.co_argcount
        result ^= self.co_nlocals
        result ^= self.co_flags
        result ^= self.co_firstlineno
        result ^= compute_hash(self.co_code)
        for name in self.co_varnames:  result ^= compute_hash(name)
        for name in self.co_freevars:  result ^= compute_hash(name)
        for name in self.co_cellvars:  result ^= compute_hash(name)
        w_result = space.wrap(intmask(result))
        for w_name in self.co_names_w:
            w_result = space.xor(w_result, space.hash(w_name))
        for w_const in self.co_consts_w:
            w_result = space.xor(w_result, space.hash(w_const))
        return w_result

    @unwrap_spec(argcount=int, nlocals=int, stacksize=int, flags=int,
                 codestring=str,
                 filename=str, name=str, firstlineno=int,
                 lnotab=str, magic=int)
    def descr_code__new__(space, w_subtype,
                          argcount, nlocals, stacksize, flags,
                          codestring, w_constants, w_names,
                          w_varnames, filename, name, firstlineno,
                          lnotab, w_freevars=None, w_cellvars=None,
                          magic=default_magic):
        if argcount < 0:
            raise oefmt(space.w_ValueError,
                        "code: argcount must not be negative")
        if nlocals < 0:
            raise oefmt(space.w_ValueError,
                        "code: nlocals must not be negative")
        if not space.isinstance_w(w_constants, space.w_tuple):
            raise oefmt(space.w_TypeError, "Expected tuple for constants")
        consts_w = space.fixedview(w_constants)
        names = unpack_str_tuple(space, w_names)
        varnames = unpack_str_tuple(space, w_varnames)
        if w_freevars is not None:
            freevars = unpack_str_tuple(space, w_freevars)
        else:
            freevars = []
        if w_cellvars is not None:
            cellvars = unpack_str_tuple(space, w_cellvars)
        else:
            cellvars = []
        code = space.allocate_instance(PyCode, w_subtype)
        PyCode.__init__(code, space, argcount, nlocals, stacksize, flags, codestring, consts_w[:], names,
                      varnames, filename, name, firstlineno, lnotab, freevars, cellvars, magic=magic)
        return space.wrap(code)

    def descr__reduce__(self, space):
        from pypy.interpreter.mixedmodule import MixedModule
        w_mod    = space.getbuiltinmodule('_pickle_support')
        mod      = space.interp_w(MixedModule, w_mod)
        new_inst = mod.get('code_new')
        w        = space.wrap
        tup      = [
            w(self.co_argcount),
            w(self.co_nlocals),
            w(self.co_stacksize),
            w(self.co_flags),
            space.newbytes(self.co_code),
            space.newtuple(self.co_consts_w),
            space.newtuple(self.co_names_w),
            space.newtuple([w(v) for v in self.co_varnames]),
            w(self.co_filename),
            w(self.co_name),
            w(self.co_firstlineno),
            space.newbytes(self.co_lnotab),
            space.newtuple([w(v) for v in self.co_freevars]),
            space.newtuple([w(v) for v in self.co_cellvars]),
            w(self.magic),
        ]
        return space.newtuple([new_inst, space.newtuple(tup)])

    def get_repr(self):
        return "<code object %s, file '%s', line %d>" % (
            self.co_name, self.co_filename, self.co_firstlineno)

    def __repr__(self):
        return self.get_repr()

    def repr(self, space):
        return space.wrap(self.get_repr())