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pypy-postgresql / pypy / objspace / flow / model.py

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# The model produced by the flowobjspace
# this is to be used by the translator mainly.
# 
# the below object/attribute model evolved from
# a discussion in Berlin, 4th of october 2003
import py
from pypy.tool.uid import uid, Hashable
from pypy.tool.descriptor import roproperty
from pypy.tool.sourcetools import PY_IDENTIFIER, nice_repr_for_func
from pypy.rlib.rarithmetic import is_valid_int, r_longlong, r_ulonglong, r_uint


"""
    memory size before and after introduction of __slots__
    using targetpypymain with -no-c

    slottified          annotation  ann+genc
    -------------------------------------------
    nothing             321 MB      442 MB
    Var/Const/SpaceOp   205 MB      325 MB
    + Link              189 MB      311 MB
    + Block             185 MB      304 MB
    
    Dropping Variable.instances and using
    just an instancenames dict brought
    annotation down to 160 MB.
    Computing the Variable.renamed attribute
    and dropping Variable.instancenames
    got annotation down to 109 MB.
    Probably an effect of less fragmentation.
"""

__metaclass__ = type


class FunctionGraph(object):
    __slots__ = ['startblock', 'returnblock', 'exceptblock', '__dict__']
    
    def __init__(self, name, startblock, return_var=None):
        self.name        = name    # function name (possibly mangled already)
        self.startblock  = startblock
        # build default returnblock
        self.returnblock = Block([return_var or Variable()])
        self.returnblock.operations = ()
        self.returnblock.exits      = ()
        # block corresponding to exception results
        self.exceptblock = Block([Variable('etype'),   # exception class
                                  Variable('evalue')])  # exception value
        self.exceptblock.operations = ()
        self.exceptblock.exits      = ()
        self.tag = None

    def getargs(self):
        return self.startblock.inputargs

    def getreturnvar(self):
        return self.returnblock.inputargs[0]

    def getsource(self):
        from pypy.tool.sourcetools import getsource
        func = self.func    # can raise AttributeError
        src = getsource(self.func)
        if src is None:
            raise AttributeError('source not found')
        return src
    source = roproperty(getsource)
    
    def getstartline(self):
        return self.func.func_code.co_firstlineno
    startline = roproperty(getstartline)
    
    def getfilename(self):
        return self.func.func_code.co_filename
    filename = roproperty(getfilename)
    
    def __str__(self):
        if hasattr(self, 'func'):
            return nice_repr_for_func(self.func, self.name)
        else:
            return self.name

    def __repr__(self):
        return '<FunctionGraph of %s at 0x%x>' % (self, uid(self))

    def iterblocks(self):
        block = self.startblock
        yield block
        seen = {block: True}
        stack = list(block.exits[::-1])
        while stack:
            block = stack.pop().target
            if block not in seen:
                yield block
                seen[block] = True
                stack += block.exits[::-1]

    def iterlinks(self):
        block = self.startblock
        seen = {block: True}
        stack = list(block.exits[::-1])
        while stack:
            link = stack.pop()
            yield link
            block = link.target
            if block not in seen:
                seen[block] = True
                stack += block.exits[::-1]

    def iterblockops(self):
        for block in self.iterblocks():
            for op in block.operations:
                yield block, op

    def show(self, t=None):
        from pypy.translator.tool.graphpage import FlowGraphPage
        FlowGraphPage(t, [self]).display()


class Link(object):

    __slots__ = """args target exitcase llexitcase prevblock
                last_exception last_exc_value""".split()

    def __init__(self, args, target, exitcase=None):
        if target is not None:
            assert len(args) == len(target.inputargs), "output args mismatch"
        self.args = list(args)     # mixed list of var/const
        self.target = target       # block
        self.exitcase = exitcase   # this is a concrete value
        self.prevblock = None      # the block this Link is an exit of

        # exception passing vars
        self.last_exception = None
        self.last_exc_value = None

    # right now only exception handling needs to introduce new variables on the links
    def extravars(self, last_exception=None, last_exc_value=None):
        self.last_exception = last_exception
        self.last_exc_value = last_exc_value

    def getextravars(self):
        "Return the extra vars created by this Link."
        result = []
        if isinstance(self.last_exception, Variable):
            result.append(self.last_exception)
        if isinstance(self.last_exc_value, Variable):
            result.append(self.last_exc_value)
        return result

    def copy(self, rename=lambda x: x):
        newargs = [rename(a) for a in self.args]
        newlink = Link(newargs, self.target, self.exitcase)
        newlink.prevblock = self.prevblock
        newlink.last_exception = rename(self.last_exception)
        newlink.last_exc_value = rename(self.last_exc_value)
        if hasattr(self, 'llexitcase'):
            newlink.llexitcase = self.llexitcase
        return newlink

    def settarget(self, targetblock):
        assert len(self.args) == len(targetblock.inputargs), (
            "output args mismatch")
        self.target = targetblock

    def __repr__(self):
        return "link from %s to %s" % (str(self.prevblock), str(self.target))

    def show(self):
        from pypy.translator.tool.graphpage import try_show
        try_show(self)


class Block(object):
    __slots__ = """inputargs operations exitswitch
                exits blockcolor""".split()
    
    def __init__(self, inputargs):
        self.inputargs = list(inputargs)  # mixed list of variable/const XXX 
        self.operations = []              # list of SpaceOperation(s)
        self.exitswitch = None            # a variable or
                                          #  Constant(last_exception), see below
        self.exits      = []              # list of Link(s)

    def at(self):
        if self.operations and self.operations[0].offset >= 0:
            return "@%d" % self.operations[0].offset
        else:
            return ""

    def __str__(self):
        if self.operations:
            txt = "block@%d" % self.operations[0].offset
        else:
            if (not self.exits) and len(self.inputargs) == 1:
                txt = "return block"
            elif (not self.exits) and len(self.inputargs) == 2:
                txt = "raise block"
            else:
                txt = "codeless block"
        return txt
    
    def __repr__(self):
        txt = "%s with %d exits" % (str(self), len(self.exits))
        if self.exitswitch:
            txt = "%s(%s)" % (txt, self.exitswitch)
        return txt

    def getvariables(self):
        "Return all variables mentioned in this Block."
        result = self.inputargs[:]
        for op in self.operations:
            result += op.args
            result.append(op.result)
        return uniqueitems([w for w in result if isinstance(w, Variable)])

    def getconstants(self):
        "Return all constants mentioned in this Block."
        result = self.inputargs[:]
        for op in self.operations:
            result += op.args
        return uniqueitems([w for w in result if isinstance(w, Constant)])

    def renamevariables(self, mapping):
        for a in mapping:
            assert isinstance(a, Variable), a
        self.inputargs = [mapping.get(a, a) for a in self.inputargs]
        for op in self.operations:
            op.args = [mapping.get(a, a) for a in op.args]
            op.result = mapping.get(op.result, op.result)
        self.exitswitch = mapping.get(self.exitswitch, self.exitswitch)
        for link in self.exits:
            link.args = [mapping.get(a, a) for a in link.args]

    def closeblock(self, *exits):
        assert self.exits == [], "block already closed"
        self.recloseblock(*exits)
        
    def recloseblock(self, *exits):
        for exit in exits:
            exit.prevblock = self
        self.exits = exits

    def show(self):
        from pypy.translator.tool.graphpage import try_show
        try_show(self)


class Variable(object):
    __slots__ = ["_name", "_nr", "concretetype"]

##    def getter(x): return x._ct
##    def setter(x, ct):
##        if repr(ct) == '<* PyObject>':
##            import pdb; pdb.set_trace()
##        x._ct = ct
##    concretetype = property(getter, setter)

    dummyname = 'v'
    namesdict = {dummyname : (dummyname, 0)}

    def name(self):
        _name = self._name
        _nr = self._nr
        if _nr == -1:
            # consume numbers lazily
            nd = self.namesdict
            _nr = self._nr = nd[_name][1]
            nd[_name] = (_name, _nr + 1)
        return "%s%d" % (_name, _nr)
    name = property(name)

    def renamed(self):
        return self._name is not self.dummyname
    renamed = property(renamed)
    
    def __init__(self, name=None):
        self._name = self.dummyname
        self._nr = -1
        # numbers are bound lazily, when the name is requested
        if name is not None:
            self.rename(name)

    def __repr__(self):
        return self.name

    def rename(self, name):
        if self._name is not self.dummyname:   # don't rename several times
            return
        if type(name) is not str:
            #assert isinstance(name, Variable) -- disabled for speed reasons
            name = name._name
            if name is self.dummyname:    # the other Variable wasn't renamed either
                return
        else:
            # remove strange characters in the name
            name = name.translate(PY_IDENTIFIER) + '_'
            if name[0] <= '9':   # skipped the   '0' <=   which is always true
                name = '_' + name
            name = self.namesdict.setdefault(name, (name, 0))[0]
        self._name = name
        self._nr = -1

    def set_name_from(self, v):
        # this is for SSI_to_SSA only which should not know about internals
        v.name  # make sure v's name is finalized
        self._name = v._name
        self._nr = v._nr

    def set_name(self, name, nr):
        # this is for wrapper.py which wants to assign a name explicitly
        self._name = intern(name)
        self._nr = nr


class Constant(Hashable):
    __slots__ = ["concretetype"]

    def __init__(self, value, concretetype = None):
        Hashable.__init__(self, value)
        if concretetype is not None:
            self.concretetype = concretetype


class UnwrapException(Exception):
    """Attempted to unwrap a Variable."""

class WrapException(Exception):
    """Attempted wrapping of a type that cannot sanely appear in flow graph or
    during its construction"""


class SpaceOperation(object):
    __slots__ = "opname args result offset".split()

    def __init__(self, opname, args, result, offset=-1):
        self.opname = intern(opname)      # operation name
        self.args   = list(args)  # mixed list of var/const
        self.result = result      # either Variable or Constant instance
        self.offset = offset      # offset in code string

    def __eq__(self, other):
        return (self.__class__ is other.__class__ and 
                self.opname == other.opname and
                self.args == other.args and
                self.result == other.result)

    def __ne__(self, other):
        return not (self == other)

    def __hash__(self):
        return hash((self.opname,tuple(self.args),self.result))

    def __repr__(self):
        return "%r = %s(%s)" % (self.result, self.opname,
                                ", ".join(map(repr, self.args)))

class Atom(object):
    def __init__(self, name):
        self.__name__ = name # make save_global happy
    def __repr__(self):
        return self.__name__

last_exception = Atom('last_exception')
c_last_exception = Constant(last_exception)
# if Block().exitswitch == Constant(last_exception), it means that we are
# interested in catching the exception that the *last operation* of the
# block could raise.  The exitcases of the links are None for no exception
# or XxxError classes to catch the matching exceptions.

def uniqueitems(lst):
    "Returns a list with duplicate elements removed."
    result = []
    seen = {}
    for item in lst:
        if item not in seen:
            result.append(item)
            seen[item] = True
    return result


def flattenobj(*args):
    for arg in args:
        try:
            for atom in flattenobj(*arg):
                yield atom
        except: yield arg

def mkentrymap(funcgraph):
    "Returns a dict mapping Blocks to lists of Links."
    startlink = Link(funcgraph.getargs(), funcgraph.startblock)
    result = {funcgraph.startblock: [startlink]}
    for link in funcgraph.iterlinks():
        lst = result.setdefault(link.target, [])
        lst.append(link)
    return result

def copygraph(graph, shallow=False, varmap={}, shallowvars=False):
    "Make a copy of a flow graph."
    blockmap = {}
    varmap = varmap.copy()
    shallowvars = shallowvars or shallow

    def copyvar(v):
        if shallowvars:
            return v
        try:
            return varmap[v]
        except KeyError:
            if isinstance(v, Variable):
                v2 = varmap[v] = Variable(v)
                if hasattr(v, 'concretetype'):
                    v2.concretetype = v.concretetype
                return v2
            else:
                return v

    def copyblock(block):
        newblock = Block([copyvar(v) for v in block.inputargs])
        if block.operations == ():
            newblock.operations = ()
        else:
            def copyoplist(oplist):
                if shallow:
                    return oplist[:]
                result = []
                for op in oplist:
                    copyop = SpaceOperation(op.opname,
                                            [copyvar(v) for v in op.args],
                                            copyvar(op.result), op.offset)
                    #copyop.offset = op.offset
                    result.append(copyop)
                return result
            newblock.operations = copyoplist(block.operations)
        newblock.exitswitch = copyvar(block.exitswitch)
        return newblock

    for block in graph.iterblocks():
        blockmap[block] = copyblock(block)

    if graph.returnblock not in blockmap:
        blockmap[graph.returnblock] = copyblock(graph.returnblock)
    if graph.exceptblock not in blockmap:
        blockmap[graph.exceptblock] = copyblock(graph.exceptblock)

    for block, newblock in blockmap.items():
        newlinks = []
        for link in block.exits:
            newlink = link.copy(copyvar)
            newlink.target = blockmap[link.target]
            newlinks.append(newlink)
        newblock.closeblock(*newlinks)

    newstartblock = blockmap[graph.startblock]
    newgraph = FunctionGraph(graph.name, newstartblock)
    newgraph.returnblock = blockmap[graph.returnblock]
    newgraph.exceptblock = blockmap[graph.exceptblock]
    for key, value in graph.__dict__.items():
        newgraph.__dict__.setdefault(key, value)
    return newgraph

def checkgraph(graph):
    "Check the consistency of a flow graph."
    if not __debug__:
        return
    try:

        vars_previous_blocks = {}

        exitblocks = {graph.returnblock: 1,   # retval
                      graph.exceptblock: 2}   # exc_cls, exc_value

        for block, nbargs in exitblocks.items():
            assert len(block.inputargs) == nbargs
            assert block.operations == ()
            assert block.exits == ()

        def definevar(v, only_in_link=None):
            assert isinstance(v, Variable)
            assert v not in vars, "duplicate variable %r" % (v,)
            assert v not in vars_previous_blocks, (
                "variable %r used in more than one block" % (v,))
            vars[v] = only_in_link

        def usevar(v, in_link=None):
            assert v in vars
            if in_link is not None:
                assert vars[v] is None or vars[v] is in_link


        for block in graph.iterblocks():
            assert type(block.exits) is tuple, (
                "block.exits is a %s (closeblock() or recloseblock() missing?)"
                % (type(block.exits).__name__,))
            if not block.exits:
                assert block in exitblocks
            vars = {}

            for v in block.inputargs:
                definevar(v)

            for op in block.operations:
                for v in op.args:
                    assert isinstance(v, (Constant, Variable))
                    if isinstance(v, Variable):
                        usevar(v)
                    else:
                        assert v.value is not last_exception
                        #assert v.value != last_exc_value
                if op.opname == 'direct_call':
                    assert isinstance(op.args[0], Constant)
                elif op.opname == 'indirect_call':
                    assert isinstance(op.args[0], Variable)
                definevar(op.result)

            exc_links = {}
            if block.exitswitch is None:
                assert len(block.exits) <= 1
                if block.exits:
                    assert block.exits[0].exitcase is None
            elif block.exitswitch == Constant(last_exception):
                assert len(block.operations) >= 1
                # check if an exception catch is done on a reasonable
                # operation
                assert block.operations[-1].opname not in ("keepalive",
                                                           "cast_pointer",
                                                           "same_as")
                assert len(block.exits) >= 2
                assert block.exits[0].exitcase is None
                for link in block.exits[1:]:
                    assert issubclass(link.exitcase, py.builtin.BaseException)
                    exc_links[link] = True
            else:
                assert isinstance(block.exitswitch, Variable)
                assert block.exitswitch in vars
                if (len(block.exits) == 2 and block.exits[0].exitcase is False
                                          and block.exits[1].exitcase is True):
                    # a boolean switch
                    pass
                else:
                    # a multiple-cases switch (or else the False and True
                    # branches are in the wrong order)
                    assert len(block.exits) >= 1
                    cases = [link.exitcase for link in block.exits]
                    has_default = cases[-1] == 'default'
                    for n in cases[:len(cases)-has_default]:
                        if is_valid_int(n):
                            continue
                        if isinstance(n, (r_longlong, r_ulonglong, r_uint)):
                            continue
                        if isinstance(n, (str, unicode)) and len(n) == 1:
                            continue
                        assert n != 'default', (
                            "'default' branch of a switch is not the last exit"
                            )
                        assert n is not None, (
                            "exitswitch Variable followed by a None exitcase")
                        raise AssertionError(
                            "switch on a non-primitive value %r" % (n,))

            allexitcases = {}
            for link in block.exits:
                assert len(link.args) == len(link.target.inputargs)
                assert link.prevblock is block
                exc_link = link in exc_links
                if exc_link:
                    for v in [link.last_exception, link.last_exc_value]:
                        assert isinstance(v, (Variable, Constant))
                        if isinstance(v, Variable):
                            definevar(v, only_in_link=link)
                else:
                    assert link.last_exception is None
                    assert link.last_exc_value is None
                for v in link.args:
                    assert isinstance(v, (Constant, Variable))
                    if isinstance(v, Variable):
                        usevar(v, in_link=link)
                        if exc_link:
                            assert v != block.operations[-1].result
                    #else:
                    #    if not exc_link:
                    #        assert v.value is not last_exception
                    #        #assert v.value != last_exc_value
                allexitcases[link.exitcase] = True
            assert len(allexitcases) == len(block.exits)
            vars_previous_blocks.update(vars)

    except AssertionError, e:
        # hack for debug tools only
        #graph.show()  # <== ENABLE THIS TO SEE THE BROKEN GRAPH
        if block and not hasattr(e, '__annotator_block'):
            setattr(e, '__annotator_block', block)
        raise

def summary(graph):
    # return a summary of the instructions found in a graph
    insns = {}
    for block in graph.iterblocks():
        for op in block.operations:
            if op.opname != 'same_as':
                insns[op.opname] = insns.get(op.opname, 0) + 1
    return insns

def safe_iterblocks(graph):
    # for debugging or displaying broken graphs.
    # You still have to check that the yielded blocks are really Blocks.
    block = getattr(graph, 'startblock', None)
    yield block
    seen = {block: True}
    stack = list(getattr(block, 'exits', [])[::-1])
    while stack:
        block = stack.pop().target
        if block not in seen:
            yield block
            seen[block] = True
            stack += getattr(block, 'exits', [])[::-1]

def safe_iterlinks(graph):
    # for debugging or displaying broken graphs.
    # You still have to check that the yielded links are really Links.
    block = getattr(graph, 'startblock', None)
    seen = {block: True}
    stack = list(getattr(block, 'exits', [])[::-1])
    while stack:
        link = stack.pop()
        yield link
        block = getattr(link, 'target', None)
        if block not in seen:
            seen[block] = True
            stack += getattr(block, 'exits', [])[::-1]