proxy.py revision 13714:35636064b7a1 
1# Copyright (c) 2018 ARM Limited
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13# Copyright (c) 2004-2006 The Regents of The University of Michigan
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38#
39# Authors: Steve Reinhardt
40#          Nathan Binkert
41
42#####################################################################
43#
44# Proxy object support.
45#
46#####################################################################
47
48from __future__ import print_function
49from __future__ import absolute_import
50
51import copy
52
53from . import params
54
55class BaseProxy(object):
56    def __init__(self, search_self, search_up):
57        self._search_self = search_self
58        self._search_up = search_up
59        self._multipliers = []
60
61    def __str__(self):
62        if self._search_self and not self._search_up:
63            s = 'Self'
64        elif not self._search_self and self._search_up:
65            s = 'Parent'
66        else:
67            s = 'ConfusedProxy'
68        return s + '.' + self.path()
69
70    def __setattr__(self, attr, value):
71        if not attr.startswith('_'):
72            raise AttributeError(
73                "cannot set attribute '%s' on proxy object" % attr)
74        super(BaseProxy, self).__setattr__(attr, value)
75
76    # support for multiplying proxies by constants or other proxies to
77    # other params
78    def __mul__(self, other):
79        if not (isinstance(other, (int, long, float)) or isproxy(other)):
80            raise TypeError(
81                "Proxy multiplier must be a constant or a proxy to a param")
82        self._multipliers.append(other)
83        return self
84
85    __rmul__ = __mul__
86
87    def _mulcheck(self, result, base):
88        for multiplier in self._multipliers:
89            if isproxy(multiplier):
90                multiplier = multiplier.unproxy(base)
91                # assert that we are multiplying with a compatible
92                # param
93                if not isinstance(multiplier, params.NumericParamValue):
94                    raise TypeError(
95                        "Proxy multiplier must be a numerical param")
96                multiplier = multiplier.getValue()
97            result *= multiplier
98        return result
99
100    def unproxy(self, base):
101        obj = base
102        done = False
103
104        if self._search_self:
105            result, done = self.find(obj)
106
107        if self._search_up:
108            # Search up the tree but mark ourself
109            # as visited to avoid a self-reference
110            self._visited = True
111            obj._visited = True
112            while not done:
113                obj = obj._parent
114                if not obj:
115                    break
116                result, done = self.find(obj)
117
118            self._visited = False
119            base._visited = False
120
121        if not done:
122            raise AttributeError(
123                "Can't resolve proxy '%s' of type '%s' from '%s'" % \
124                  (self.path(), self._pdesc.ptype_str, base.path()))
125
126        if isinstance(result, BaseProxy):
127            if result == self:
128                raise RuntimeError("Cycle in unproxy")
129            result = result.unproxy(obj)
130
131        return self._mulcheck(result, base)
132
133    def getindex(obj, index):
134        if index == None:
135            return obj
136        try:
137            obj = obj[index]
138        except TypeError:
139            if index != 0:
140                raise
141            # if index is 0 and item is not subscriptable, just
142            # use item itself (so cpu[0] works on uniprocessors)
143        return obj
144    getindex = staticmethod(getindex)
145
146    # This method should be called once the proxy is assigned to a
147    # particular parameter or port to set the expected type of the
148    # resolved proxy
149    def set_param_desc(self, pdesc):
150        self._pdesc = pdesc
151
152class AttrProxy(BaseProxy):
153    def __init__(self, search_self, search_up, attr):
154        super(AttrProxy, self).__init__(search_self, search_up)
155        self._attr = attr
156        self._modifiers = []
157
158    def __getattr__(self, attr):
159        # python uses __bases__ internally for inheritance
160        if attr.startswith('_'):
161            return super(AttrProxy, self).__getattr__(self, attr)
162        if hasattr(self, '_pdesc'):
163            raise AttributeError("Attribute reference on bound proxy")
164        # Return a copy of self rather than modifying self in place
165        # since self could be an indirect reference via a variable or
166        # parameter
167        new_self = copy.deepcopy(self)
168        new_self._modifiers.append(attr)
169        return new_self
170
171    # support indexing on proxies (e.g., Self.cpu[0])
172    def __getitem__(self, key):
173        if not isinstance(key, int):
174            raise TypeError("Proxy object requires integer index")
175        if hasattr(self, '_pdesc'):
176            raise AttributeError("Index operation on bound proxy")
177        new_self = copy.deepcopy(self)
178        new_self._modifiers.append(key)
179        return new_self
180
181    def find(self, obj):
182        try:
183            val = getattr(obj, self._attr)
184            visited = False
185            if hasattr(val, '_visited'):
186                visited = getattr(val, '_visited')
187
188            if not visited:
189                # for any additional unproxying to be done, pass the
190                # current, rather than the original object so that proxy
191                # has the right context
192                obj = val
193            else:
194                return None, False
195        except:
196            return None, False
197        while isproxy(val):
198            val = val.unproxy(obj)
199        for m in self._modifiers:
200            if isinstance(m, str):
201                val = getattr(val, m)
202            elif isinstance(m, int):
203                val = val[m]
204            else:
205                assert("Item must be string or integer")
206            while isproxy(val):
207                val = val.unproxy(obj)
208        return val, True
209
210    def path(self):
211        p = self._attr
212        for m in self._modifiers:
213            if isinstance(m, str):
214                p += '.%s' % m
215            elif isinstance(m, int):
216                p += '[%d]' % m
217            else:
218                assert("Item must be string or integer")
219        return p
220
221class AnyProxy(BaseProxy):
222    def find(self, obj):
223        return obj.find_any(self._pdesc.ptype)
224
225    def path(self):
226        return 'any'
227
228# The AllProxy traverses the entire sub-tree (not only the children)
229# and adds all objects of a specific type
230class AllProxy(BaseProxy):
231    def find(self, obj):
232        return obj.find_all(self._pdesc.ptype)
233
234    def path(self):
235        return 'all'
236
237def isproxy(obj):
238    if isinstance(obj, (BaseProxy, params.EthernetAddr)):
239        return True
240    elif isinstance(obj, (list, tuple)):
241        for v in obj:
242            if isproxy(v):
243                return True
244    return False
245
246class ProxyFactory(object):
247    def __init__(self, search_self, search_up):
248        self.search_self = search_self
249        self.search_up = search_up
250
251    def __getattr__(self, attr):
252        if attr == 'any':
253            return AnyProxy(self.search_self, self.search_up)
254        elif attr == 'all':
255            if self.search_up:
256                assert("Parant.all is not supported")
257            return AllProxy(self.search_self, self.search_up)
258        else:
259            return AttrProxy(self.search_self, self.search_up, attr)
260
261# global objects for handling proxies
262Parent = ProxyFactory(search_self = False, search_up = True)
263Self = ProxyFactory(search_self = True, search_up = False)
264
265# limit exports on 'from proxy import *'
266__all__ = ['Parent', 'Self']
267
268# see comment on imports at end of __init__.py.
269import params # for EthernetAddr
270