1 | """A flow graph representation for Python bytecode"""
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2 |
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3 | import dis
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4 | import types
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5 | import sys
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6 |
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7 | from compiler import misc
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8 | from compiler.consts \
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9 | import CO_OPTIMIZED, CO_NEWLOCALS, CO_VARARGS, CO_VARKEYWORDS
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10 |
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11 | class FlowGraph:
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12 | def __init__(self):
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13 | self.current = self.entry = Block()
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14 | self.exit = Block("exit")
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15 | self.blocks = misc.Set()
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16 | self.blocks.add(self.entry)
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17 | self.blocks.add(self.exit)
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18 |
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19 | def startBlock(self, block):
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20 | if self._debug:
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21 | if self.current:
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22 | print "end", repr(self.current)
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23 | print " next", self.current.next
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24 | print " ", self.current.get_children()
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25 | print repr(block)
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26 | self.current = block
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27 |
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28 | def nextBlock(self, block=None):
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29 | # XXX think we need to specify when there is implicit transfer
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30 | # from one block to the next. might be better to represent this
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31 | # with explicit JUMP_ABSOLUTE instructions that are optimized
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32 | # out when they are unnecessary.
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33 | #
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34 | # I think this strategy works: each block has a child
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35 | # designated as "next" which is returned as the last of the
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36 | # children. because the nodes in a graph are emitted in
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37 | # reverse post order, the "next" block will always be emitted
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38 | # immediately after its parent.
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39 | # Worry: maintaining this invariant could be tricky
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40 | if block is None:
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41 | block = self.newBlock()
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42 |
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43 | # Note: If the current block ends with an unconditional
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44 | # control transfer, then it is incorrect to add an implicit
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45 | # transfer to the block graph. The current code requires
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46 | # these edges to get the blocks emitted in the right order,
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47 | # however. :-( If a client needs to remove these edges, call
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48 | # pruneEdges().
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49 |
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50 | self.current.addNext(block)
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51 | self.startBlock(block)
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52 |
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53 | def newBlock(self):
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54 | b = Block()
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55 | self.blocks.add(b)
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56 | return b
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57 |
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58 | def startExitBlock(self):
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59 | self.startBlock(self.exit)
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60 |
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61 | _debug = 0
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62 |
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63 | def _enable_debug(self):
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64 | self._debug = 1
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65 |
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66 | def _disable_debug(self):
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67 | self._debug = 0
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68 |
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69 | def emit(self, *inst):
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70 | if self._debug:
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71 | print "\t", inst
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72 | if inst[0] in ['RETURN_VALUE', 'YIELD_VALUE']:
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73 | self.current.addOutEdge(self.exit)
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74 | if len(inst) == 2 and isinstance(inst[1], Block):
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75 | self.current.addOutEdge(inst[1])
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76 | self.current.emit(inst)
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77 |
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78 | def getBlocksInOrder(self):
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79 | """Return the blocks in reverse postorder
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80 |
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81 | i.e. each node appears before all of its successors
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82 | """
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83 | # XXX make sure every node that doesn't have an explicit next
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84 | # is set so that next points to exit
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85 | for b in self.blocks.elements():
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86 | if b is self.exit:
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87 | continue
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88 | if not b.next:
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89 | b.addNext(self.exit)
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90 | order = dfs_postorder(self.entry, {})
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91 | order.reverse()
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92 | self.fixupOrder(order, self.exit)
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93 | # hack alert
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94 | if not self.exit in order:
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95 | order.append(self.exit)
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96 |
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97 | return order
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98 |
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99 | def fixupOrder(self, blocks, default_next):
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100 | """Fixup bad order introduced by DFS."""
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101 |
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102 | # XXX This is a total mess. There must be a better way to get
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103 | # the code blocks in the right order.
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104 |
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105 | self.fixupOrderHonorNext(blocks, default_next)
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106 | self.fixupOrderForward(blocks, default_next)
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107 |
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108 | def fixupOrderHonorNext(self, blocks, default_next):
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109 | """Fix one problem with DFS.
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110 |
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111 | The DFS uses child block, but doesn't know about the special
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112 | "next" block. As a result, the DFS can order blocks so that a
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113 | block isn't next to the right block for implicit control
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114 | transfers.
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115 | """
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116 | index = {}
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117 | for i in range(len(blocks)):
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118 | index[blocks[i]] = i
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119 |
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120 | for i in range(0, len(blocks) - 1):
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121 | b = blocks[i]
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122 | n = blocks[i + 1]
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123 | if not b.next or b.next[0] == default_next or b.next[0] == n:
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124 | continue
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125 | # The blocks are in the wrong order. Find the chain of
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126 | # blocks to insert where they belong.
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127 | cur = b
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128 | chain = []
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129 | elt = cur
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130 | while elt.next and elt.next[0] != default_next:
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131 | chain.append(elt.next[0])
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132 | elt = elt.next[0]
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133 | # Now remove the blocks in the chain from the current
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134 | # block list, so that they can be re-inserted.
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135 | l = []
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136 | for b in chain:
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137 | assert index[b] > i
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138 | l.append((index[b], b))
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139 | l.sort()
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140 | l.reverse()
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141 | for j, b in l:
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142 | del blocks[index[b]]
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143 | # Insert the chain in the proper location
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144 | blocks[i:i + 1] = [cur] + chain
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145 | # Finally, re-compute the block indexes
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146 | for i in range(len(blocks)):
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147 | index[blocks[i]] = i
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148 |
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149 | def fixupOrderForward(self, blocks, default_next):
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150 | """Make sure all JUMP_FORWARDs jump forward"""
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151 | index = {}
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152 | chains = []
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153 | cur = []
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154 | for b in blocks:
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155 | index[b] = len(chains)
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156 | cur.append(b)
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157 | if b.next and b.next[0] == default_next:
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158 | chains.append(cur)
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159 | cur = []
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160 | chains.append(cur)
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161 |
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162 | while 1:
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163 | constraints = []
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164 |
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165 | for i in range(len(chains)):
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166 | l = chains[i]
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167 | for b in l:
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168 | for c in b.get_children():
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169 | if index[c] < i:
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170 | forward_p = 0
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171 | for inst in b.insts:
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172 | if inst[0] == 'JUMP_FORWARD':
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173 | if inst[1] == c:
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174 | forward_p = 1
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175 | if not forward_p:
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176 | continue
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177 | constraints.append((index[c], i))
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178 |
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179 | if not constraints:
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180 | break
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181 |
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182 | # XXX just do one for now
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183 | # do swaps to get things in the right order
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184 | goes_before, a_chain = constraints[0]
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185 | assert a_chain > goes_before
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186 | c = chains[a_chain]
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187 | chains.remove(c)
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188 | chains.insert(goes_before, c)
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189 |
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190 | del blocks[:]
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191 | for c in chains:
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192 | for b in c:
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193 | blocks.append(b)
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194 |
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195 | def getBlocks(self):
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196 | return self.blocks.elements()
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197 |
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198 | def getRoot(self):
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199 | """Return nodes appropriate for use with dominator"""
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200 | return self.entry
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201 |
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202 | def getContainedGraphs(self):
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203 | l = []
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204 | for b in self.getBlocks():
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205 | l.extend(b.getContainedGraphs())
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206 | return l
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207 |
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208 | def dfs_postorder(b, seen):
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209 | """Depth-first search of tree rooted at b, return in postorder"""
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210 | order = []
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211 | seen[b] = b
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212 | for c in b.get_children():
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213 | if c in seen:
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214 | continue
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215 | order = order + dfs_postorder(c, seen)
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216 | order.append(b)
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217 | return order
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218 |
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219 | class Block:
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220 | _count = 0
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221 |
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222 | def __init__(self, label=''):
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223 | self.insts = []
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224 | self.inEdges = misc.Set()
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225 | self.outEdges = misc.Set()
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226 | self.label = label
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227 | self.bid = Block._count
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228 | self.next = []
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229 | Block._count = Block._count + 1
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230 |
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231 | def __repr__(self):
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232 | if self.label:
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233 | return "<block %s id=%d>" % (self.label, self.bid)
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234 | else:
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235 | return "<block id=%d>" % (self.bid)
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236 |
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237 | def __str__(self):
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238 | insts = map(str, self.insts)
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239 | return "<block %s %d:\n%s>" % (self.label, self.bid,
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240 | '\n'.join(insts))
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241 |
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242 | def emit(self, inst):
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243 | op = inst[0]
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244 | if op[:4] == 'JUMP':
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245 | self.outEdges.add(inst[1])
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246 | self.insts.append(inst)
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247 |
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248 | def getInstructions(self):
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249 | return self.insts
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250 |
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251 | def addInEdge(self, block):
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252 | self.inEdges.add(block)
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253 |
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254 | def addOutEdge(self, block):
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255 | self.outEdges.add(block)
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256 |
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257 | def addNext(self, block):
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258 | self.next.append(block)
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259 | assert len(self.next) == 1, map(str, self.next)
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260 |
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261 | _uncond_transfer = ('RETURN_VALUE', 'RAISE_VARARGS', 'YIELD_VALUE',
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262 | 'JUMP_ABSOLUTE', 'JUMP_FORWARD', 'CONTINUE_LOOP')
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263 |
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264 | def pruneNext(self):
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265 | """Remove bogus edge for unconditional transfers
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266 |
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267 | Each block has a next edge that accounts for implicit control
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268 | transfers, e.g. from a JUMP_IF_FALSE to the block that will be
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269 | executed if the test is true.
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270 |
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271 | These edges must remain for the current assembler code to
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272 | work. If they are removed, the dfs_postorder gets things in
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273 | weird orders. However, they shouldn't be there for other
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274 | purposes, e.g. conversion to SSA form. This method will
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275 | remove the next edge when it follows an unconditional control
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276 | transfer.
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277 | """
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278 | try:
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279 | op, arg = self.insts[-1]
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280 | except (IndexError, ValueError):
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281 | return
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282 | if op in self._uncond_transfer:
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283 | self.next = []
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284 |
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285 | def get_children(self):
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286 | if self.next and self.next[0] in self.outEdges:
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287 | self.outEdges.remove(self.next[0])
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288 | return self.outEdges.elements() + self.next
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289 |
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290 | def getContainedGraphs(self):
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291 | """Return all graphs contained within this block.
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292 |
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293 | For example, a MAKE_FUNCTION block will contain a reference to
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294 | the graph for the function body.
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295 | """
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296 | contained = []
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297 | for inst in self.insts:
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298 | if len(inst) == 1:
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299 | continue
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300 | op = inst[1]
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301 | if hasattr(op, 'graph'):
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302 | contained.append(op.graph)
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303 | return contained
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304 |
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305 | # flags for code objects
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306 |
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307 | # the FlowGraph is transformed in place; it exists in one of these states
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308 | RAW = "RAW"
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309 | FLAT = "FLAT"
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310 | CONV = "CONV"
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311 | DONE = "DONE"
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312 |
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313 | class PyFlowGraph(FlowGraph):
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314 | super_init = FlowGraph.__init__
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315 |
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316 | def __init__(self, name, filename, args=(), optimized=0, klass=None):
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317 | self.super_init()
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318 | self.name = name
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319 | self.filename = filename
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320 | self.docstring = None
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321 | self.args = args # XXX
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322 | self.argcount = getArgCount(args)
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323 | self.klass = klass
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324 | if optimized:
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325 | self.flags = CO_OPTIMIZED | CO_NEWLOCALS
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326 | else:
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327 | self.flags = 0
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328 | self.consts = []
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329 | self.names = []
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330 | # Free variables found by the symbol table scan, including
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331 | # variables used only in nested scopes, are included here.
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332 | self.freevars = []
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333 | self.cellvars = []
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334 | # The closure list is used to track the order of cell
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335 | # variables and free variables in the resulting code object.
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336 | # The offsets used by LOAD_CLOSURE/LOAD_DEREF refer to both
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337 | # kinds of variables.
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338 | self.closure = []
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339 | self.varnames = list(args) or []
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340 | for i in range(len(self.varnames)):
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341 | var = self.varnames[i]
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342 | if isinstance(var, TupleArg):
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343 | self.varnames[i] = var.getName()
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344 | self.stage = RAW
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345 |
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346 | def setDocstring(self, doc):
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347 | self.docstring = doc
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348 |
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349 | def setFlag(self, flag):
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350 | self.flags = self.flags | flag
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351 | if flag == CO_VARARGS:
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352 | self.argcount = self.argcount - 1
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353 |
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354 | def checkFlag(self, flag):
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355 | if self.flags & flag:
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356 | return 1
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357 |
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358 | def setFreeVars(self, names):
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359 | self.freevars = list(names)
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360 |
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361 | def setCellVars(self, names):
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362 | self.cellvars = names
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363 |
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364 | def getCode(self):
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365 | """Get a Python code object"""
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366 | assert self.stage == RAW
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367 | self.computeStackDepth()
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368 | self.flattenGraph()
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369 | assert self.stage == FLAT
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370 | self.convertArgs()
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371 | assert self.stage == CONV
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372 | self.makeByteCode()
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373 | assert self.stage == DONE
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374 | return self.newCodeObject()
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375 |
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376 | def dump(self, io=None):
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377 | if io:
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378 | save = sys.stdout
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379 | sys.stdout = io
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380 | pc = 0
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381 | for t in self.insts:
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382 | opname = t[0]
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383 | if opname == "SET_LINENO":
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384 | print
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385 | if len(t) == 1:
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386 | print "\t", "%3d" % pc, opname
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387 | pc = pc + 1
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388 | else:
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389 | print "\t", "%3d" % pc, opname, t[1]
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390 | pc = pc + 3
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391 | if io:
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392 | sys.stdout = save
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393 |
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394 | def computeStackDepth(self):
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395 | """Compute the max stack depth.
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396 |
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397 | Approach is to compute the stack effect of each basic block.
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398 | Then find the path through the code with the largest total
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399 | effect.
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400 | """
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401 | depth = {}
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402 | exit = None
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403 | for b in self.getBlocks():
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404 | depth[b] = findDepth(b.getInstructions())
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405 |
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406 | seen = {}
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407 |
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408 | def max_depth(b, d):
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409 | if b in seen:
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410 | return d
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411 | seen[b] = 1
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412 | d = d + depth[b]
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413 | children = b.get_children()
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414 | if children:
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415 | return max([max_depth(c, d) for c in children])
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416 | else:
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417 | if not b.label == "exit":
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418 | return max_depth(self.exit, d)
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419 | else:
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420 | return d
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421 |
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422 | self.stacksize = max_depth(self.entry, 0)
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423 |
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424 | def flattenGraph(self):
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425 | """Arrange the blocks in order and resolve jumps"""
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426 | assert self.stage == RAW
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427 | self.insts = insts = []
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428 | pc = 0
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429 | begin = {}
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430 | end = {}
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431 | for b in self.getBlocksInOrder():
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432 | begin[b] = pc
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433 | for inst in b.getInstructions():
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434 | insts.append(inst)
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435 | if len(inst) == 1:
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436 | pc = pc + 1
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437 | elif inst[0] != "SET_LINENO":
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438 | # arg takes 2 bytes
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439 | pc = pc + 3
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440 | end[b] = pc
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441 | pc = 0
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442 | for i in range(len(insts)):
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443 | inst = insts[i]
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444 | if len(inst) == 1:
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445 | pc = pc + 1
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446 | elif inst[0] != "SET_LINENO":
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447 | pc = pc + 3
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448 | opname = inst[0]
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449 | if self.hasjrel.has_elt(opname):
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450 | oparg = inst[1]
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451 | offset = begin[oparg] - pc
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452 | insts[i] = opname, offset
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453 | elif self.hasjabs.has_elt(opname):
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454 | insts[i] = opname, begin[inst[1]]
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455 | self.stage = FLAT
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456 |
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457 | hasjrel = misc.Set()
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458 | for i in dis.hasjrel:
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459 | hasjrel.add(dis.opname[i])
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460 | hasjabs = misc.Set()
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461 | for i in dis.hasjabs:
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462 | hasjabs.add(dis.opname[i])
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463 |
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464 | def convertArgs(self):
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465 | """Convert arguments from symbolic to concrete form"""
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466 | assert self.stage == FLAT
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467 | self.consts.insert(0, self.docstring)
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468 | self.sort_cellvars()
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469 | for i in range(len(self.insts)):
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470 | t = self.insts[i]
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471 | if len(t) == 2:
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472 | opname, oparg = t
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473 | conv = self._converters.get(opname, None)
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474 | if conv:
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475 | self.insts[i] = opname, conv(self, oparg)
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476 | self.stage = CONV
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477 |
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478 | def sort_cellvars(self):
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479 | """Sort cellvars in the order of varnames and prune from freevars.
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480 | """
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481 | cells = {}
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482 | for name in self.cellvars:
|
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483 | cells[name] = 1
|
---|
484 | self.cellvars = [name for name in self.varnames
|
---|
485 | if name in cells]
|
---|
486 | for name in self.cellvars:
|
---|
487 | del cells[name]
|
---|
488 | self.cellvars = self.cellvars + cells.keys()
|
---|
489 | self.closure = self.cellvars + self.freevars
|
---|
490 |
|
---|
491 | def _lookupName(self, name, list):
|
---|
492 | """Return index of name in list, appending if necessary
|
---|
493 |
|
---|
494 | This routine uses a list instead of a dictionary, because a
|
---|
495 | dictionary can't store two different keys if the keys have the
|
---|
496 | same value but different types, e.g. 2 and 2L. The compiler
|
---|
497 | must treat these two separately, so it does an explicit type
|
---|
498 | comparison before comparing the values.
|
---|
499 | """
|
---|
500 | t = type(name)
|
---|
501 | for i in range(len(list)):
|
---|
502 | if t == type(list[i]) and list[i] == name:
|
---|
503 | return i
|
---|
504 | end = len(list)
|
---|
505 | list.append(name)
|
---|
506 | return end
|
---|
507 |
|
---|
508 | _converters = {}
|
---|
509 | def _convert_LOAD_CONST(self, arg):
|
---|
510 | if hasattr(arg, 'getCode'):
|
---|
511 | arg = arg.getCode()
|
---|
512 | return self._lookupName(arg, self.consts)
|
---|
513 |
|
---|
514 | def _convert_LOAD_FAST(self, arg):
|
---|
515 | self._lookupName(arg, self.names)
|
---|
516 | return self._lookupName(arg, self.varnames)
|
---|
517 | _convert_STORE_FAST = _convert_LOAD_FAST
|
---|
518 | _convert_DELETE_FAST = _convert_LOAD_FAST
|
---|
519 |
|
---|
520 | def _convert_LOAD_NAME(self, arg):
|
---|
521 | if self.klass is None:
|
---|
522 | self._lookupName(arg, self.varnames)
|
---|
523 | return self._lookupName(arg, self.names)
|
---|
524 |
|
---|
525 | def _convert_NAME(self, arg):
|
---|
526 | if self.klass is None:
|
---|
527 | self._lookupName(arg, self.varnames)
|
---|
528 | return self._lookupName(arg, self.names)
|
---|
529 | _convert_STORE_NAME = _convert_NAME
|
---|
530 | _convert_DELETE_NAME = _convert_NAME
|
---|
531 | _convert_IMPORT_NAME = _convert_NAME
|
---|
532 | _convert_IMPORT_FROM = _convert_NAME
|
---|
533 | _convert_STORE_ATTR = _convert_NAME
|
---|
534 | _convert_LOAD_ATTR = _convert_NAME
|
---|
535 | _convert_DELETE_ATTR = _convert_NAME
|
---|
536 | _convert_LOAD_GLOBAL = _convert_NAME
|
---|
537 | _convert_STORE_GLOBAL = _convert_NAME
|
---|
538 | _convert_DELETE_GLOBAL = _convert_NAME
|
---|
539 |
|
---|
540 | def _convert_DEREF(self, arg):
|
---|
541 | self._lookupName(arg, self.names)
|
---|
542 | self._lookupName(arg, self.varnames)
|
---|
543 | return self._lookupName(arg, self.closure)
|
---|
544 | _convert_LOAD_DEREF = _convert_DEREF
|
---|
545 | _convert_STORE_DEREF = _convert_DEREF
|
---|
546 |
|
---|
547 | def _convert_LOAD_CLOSURE(self, arg):
|
---|
548 | self._lookupName(arg, self.varnames)
|
---|
549 | return self._lookupName(arg, self.closure)
|
---|
550 |
|
---|
551 | _cmp = list(dis.cmp_op)
|
---|
552 | def _convert_COMPARE_OP(self, arg):
|
---|
553 | return self._cmp.index(arg)
|
---|
554 |
|
---|
555 | # similarly for other opcodes...
|
---|
556 |
|
---|
557 | for name, obj in locals().items():
|
---|
558 | if name[:9] == "_convert_":
|
---|
559 | opname = name[9:]
|
---|
560 | _converters[opname] = obj
|
---|
561 | del name, obj, opname
|
---|
562 |
|
---|
563 | def makeByteCode(self):
|
---|
564 | assert self.stage == CONV
|
---|
565 | self.lnotab = lnotab = LineAddrTable()
|
---|
566 | for t in self.insts:
|
---|
567 | opname = t[0]
|
---|
568 | if len(t) == 1:
|
---|
569 | lnotab.addCode(self.opnum[opname])
|
---|
570 | else:
|
---|
571 | oparg = t[1]
|
---|
572 | if opname == "SET_LINENO":
|
---|
573 | lnotab.nextLine(oparg)
|
---|
574 | continue
|
---|
575 | hi, lo = twobyte(oparg)
|
---|
576 | try:
|
---|
577 | lnotab.addCode(self.opnum[opname], lo, hi)
|
---|
578 | except ValueError:
|
---|
579 | print opname, oparg
|
---|
580 | print self.opnum[opname], lo, hi
|
---|
581 | raise
|
---|
582 | self.stage = DONE
|
---|
583 |
|
---|
584 | opnum = {}
|
---|
585 | for num in range(len(dis.opname)):
|
---|
586 | opnum[dis.opname[num]] = num
|
---|
587 | del num
|
---|
588 |
|
---|
589 | def newCodeObject(self):
|
---|
590 | assert self.stage == DONE
|
---|
591 | if (self.flags & CO_NEWLOCALS) == 0:
|
---|
592 | nlocals = 0
|
---|
593 | else:
|
---|
594 | nlocals = len(self.varnames)
|
---|
595 | argcount = self.argcount
|
---|
596 | if self.flags & CO_VARKEYWORDS:
|
---|
597 | argcount = argcount - 1
|
---|
598 | return types.CodeType(argcount, nlocals, self.stacksize, self.flags,
|
---|
599 | self.lnotab.getCode(), self.getConsts(),
|
---|
600 | tuple(self.names), tuple(self.varnames),
|
---|
601 | self.filename, self.name, self.lnotab.firstline,
|
---|
602 | self.lnotab.getTable(), tuple(self.freevars),
|
---|
603 | tuple(self.cellvars))
|
---|
604 |
|
---|
605 | def getConsts(self):
|
---|
606 | """Return a tuple for the const slot of the code object
|
---|
607 |
|
---|
608 | Must convert references to code (MAKE_FUNCTION) to code
|
---|
609 | objects recursively.
|
---|
610 | """
|
---|
611 | l = []
|
---|
612 | for elt in self.consts:
|
---|
613 | if isinstance(elt, PyFlowGraph):
|
---|
614 | elt = elt.getCode()
|
---|
615 | l.append(elt)
|
---|
616 | return tuple(l)
|
---|
617 |
|
---|
618 | def isJump(opname):
|
---|
619 | if opname[:4] == 'JUMP':
|
---|
620 | return 1
|
---|
621 |
|
---|
622 | class TupleArg:
|
---|
623 | """Helper for marking func defs with nested tuples in arglist"""
|
---|
624 | def __init__(self, count, names):
|
---|
625 | self.count = count
|
---|
626 | self.names = names
|
---|
627 | def __repr__(self):
|
---|
628 | return "TupleArg(%s, %s)" % (self.count, self.names)
|
---|
629 | def getName(self):
|
---|
630 | return ".%d" % self.count
|
---|
631 |
|
---|
632 | def getArgCount(args):
|
---|
633 | argcount = len(args)
|
---|
634 | if args:
|
---|
635 | for arg in args:
|
---|
636 | if isinstance(arg, TupleArg):
|
---|
637 | numNames = len(misc.flatten(arg.names))
|
---|
638 | argcount = argcount - numNames
|
---|
639 | return argcount
|
---|
640 |
|
---|
641 | def twobyte(val):
|
---|
642 | """Convert an int argument into high and low bytes"""
|
---|
643 | assert isinstance(val, int)
|
---|
644 | return divmod(val, 256)
|
---|
645 |
|
---|
646 | class LineAddrTable:
|
---|
647 | """lnotab
|
---|
648 |
|
---|
649 | This class builds the lnotab, which is documented in compile.c.
|
---|
650 | Here's a brief recap:
|
---|
651 |
|
---|
652 | For each SET_LINENO instruction after the first one, two bytes are
|
---|
653 | added to lnotab. (In some cases, multiple two-byte entries are
|
---|
654 | added.) The first byte is the distance in bytes between the
|
---|
655 | instruction for the last SET_LINENO and the current SET_LINENO.
|
---|
656 | The second byte is offset in line numbers. If either offset is
|
---|
657 | greater than 255, multiple two-byte entries are added -- see
|
---|
658 | compile.c for the delicate details.
|
---|
659 | """
|
---|
660 |
|
---|
661 | def __init__(self):
|
---|
662 | self.code = []
|
---|
663 | self.codeOffset = 0
|
---|
664 | self.firstline = 0
|
---|
665 | self.lastline = 0
|
---|
666 | self.lastoff = 0
|
---|
667 | self.lnotab = []
|
---|
668 |
|
---|
669 | def addCode(self, *args):
|
---|
670 | for arg in args:
|
---|
671 | self.code.append(chr(arg))
|
---|
672 | self.codeOffset = self.codeOffset + len(args)
|
---|
673 |
|
---|
674 | def nextLine(self, lineno):
|
---|
675 | if self.firstline == 0:
|
---|
676 | self.firstline = lineno
|
---|
677 | self.lastline = lineno
|
---|
678 | else:
|
---|
679 | # compute deltas
|
---|
680 | addr = self.codeOffset - self.lastoff
|
---|
681 | line = lineno - self.lastline
|
---|
682 | # Python assumes that lineno always increases with
|
---|
683 | # increasing bytecode address (lnotab is unsigned char).
|
---|
684 | # Depending on when SET_LINENO instructions are emitted
|
---|
685 | # this is not always true. Consider the code:
|
---|
686 | # a = (1,
|
---|
687 | # b)
|
---|
688 | # In the bytecode stream, the assignment to "a" occurs
|
---|
689 | # after the loading of "b". This works with the C Python
|
---|
690 | # compiler because it only generates a SET_LINENO instruction
|
---|
691 | # for the assignment.
|
---|
692 | if line >= 0:
|
---|
693 | push = self.lnotab.append
|
---|
694 | while addr > 255:
|
---|
695 | push(255); push(0)
|
---|
696 | addr -= 255
|
---|
697 | while line > 255:
|
---|
698 | push(addr); push(255)
|
---|
699 | line -= 255
|
---|
700 | addr = 0
|
---|
701 | if addr > 0 or line > 0:
|
---|
702 | push(addr); push(line)
|
---|
703 | self.lastline = lineno
|
---|
704 | self.lastoff = self.codeOffset
|
---|
705 |
|
---|
706 | def getCode(self):
|
---|
707 | return ''.join(self.code)
|
---|
708 |
|
---|
709 | def getTable(self):
|
---|
710 | return ''.join(map(chr, self.lnotab))
|
---|
711 |
|
---|
712 | class StackDepthTracker:
|
---|
713 | # XXX 1. need to keep track of stack depth on jumps
|
---|
714 | # XXX 2. at least partly as a result, this code is broken
|
---|
715 |
|
---|
716 | def findDepth(self, insts, debug=0):
|
---|
717 | depth = 0
|
---|
718 | maxDepth = 0
|
---|
719 | for i in insts:
|
---|
720 | opname = i[0]
|
---|
721 | if debug:
|
---|
722 | print i,
|
---|
723 | delta = self.effect.get(opname, None)
|
---|
724 | if delta is not None:
|
---|
725 | depth = depth + delta
|
---|
726 | else:
|
---|
727 | # now check patterns
|
---|
728 | for pat, pat_delta in self.patterns:
|
---|
729 | if opname[:len(pat)] == pat:
|
---|
730 | delta = pat_delta
|
---|
731 | depth = depth + delta
|
---|
732 | break
|
---|
733 | # if we still haven't found a match
|
---|
734 | if delta is None:
|
---|
735 | meth = getattr(self, opname, None)
|
---|
736 | if meth is not None:
|
---|
737 | depth = depth + meth(i[1])
|
---|
738 | if depth > maxDepth:
|
---|
739 | maxDepth = depth
|
---|
740 | if debug:
|
---|
741 | print depth, maxDepth
|
---|
742 | return maxDepth
|
---|
743 |
|
---|
744 | effect = {
|
---|
745 | 'POP_TOP': -1,
|
---|
746 | 'DUP_TOP': 1,
|
---|
747 | 'LIST_APPEND': -2,
|
---|
748 | 'SLICE+1': -1,
|
---|
749 | 'SLICE+2': -1,
|
---|
750 | 'SLICE+3': -2,
|
---|
751 | 'STORE_SLICE+0': -1,
|
---|
752 | 'STORE_SLICE+1': -2,
|
---|
753 | 'STORE_SLICE+2': -2,
|
---|
754 | 'STORE_SLICE+3': -3,
|
---|
755 | 'DELETE_SLICE+0': -1,
|
---|
756 | 'DELETE_SLICE+1': -2,
|
---|
757 | 'DELETE_SLICE+2': -2,
|
---|
758 | 'DELETE_SLICE+3': -3,
|
---|
759 | 'STORE_SUBSCR': -3,
|
---|
760 | 'DELETE_SUBSCR': -2,
|
---|
761 | # PRINT_EXPR?
|
---|
762 | 'PRINT_ITEM': -1,
|
---|
763 | 'RETURN_VALUE': -1,
|
---|
764 | 'YIELD_VALUE': -1,
|
---|
765 | 'EXEC_STMT': -3,
|
---|
766 | 'BUILD_CLASS': -2,
|
---|
767 | 'STORE_NAME': -1,
|
---|
768 | 'STORE_ATTR': -2,
|
---|
769 | 'DELETE_ATTR': -1,
|
---|
770 | 'STORE_GLOBAL': -1,
|
---|
771 | 'BUILD_MAP': 1,
|
---|
772 | 'COMPARE_OP': -1,
|
---|
773 | 'STORE_FAST': -1,
|
---|
774 | 'IMPORT_STAR': -1,
|
---|
775 | 'IMPORT_NAME': -1,
|
---|
776 | 'IMPORT_FROM': 1,
|
---|
777 | 'LOAD_ATTR': 0, # unlike other loads
|
---|
778 | # close enough...
|
---|
779 | 'SETUP_EXCEPT': 3,
|
---|
780 | 'SETUP_FINALLY': 3,
|
---|
781 | 'FOR_ITER': 1,
|
---|
782 | 'WITH_CLEANUP': -1,
|
---|
783 | }
|
---|
784 | # use pattern match
|
---|
785 | patterns = [
|
---|
786 | ('BINARY_', -1),
|
---|
787 | ('LOAD_', 1),
|
---|
788 | ]
|
---|
789 |
|
---|
790 | def UNPACK_SEQUENCE(self, count):
|
---|
791 | return count-1
|
---|
792 | def BUILD_TUPLE(self, count):
|
---|
793 | return -count+1
|
---|
794 | def BUILD_LIST(self, count):
|
---|
795 | return -count+1
|
---|
796 | def CALL_FUNCTION(self, argc):
|
---|
797 | hi, lo = divmod(argc, 256)
|
---|
798 | return -(lo + hi * 2)
|
---|
799 | def CALL_FUNCTION_VAR(self, argc):
|
---|
800 | return self.CALL_FUNCTION(argc)-1
|
---|
801 | def CALL_FUNCTION_KW(self, argc):
|
---|
802 | return self.CALL_FUNCTION(argc)-1
|
---|
803 | def CALL_FUNCTION_VAR_KW(self, argc):
|
---|
804 | return self.CALL_FUNCTION(argc)-2
|
---|
805 | def MAKE_FUNCTION(self, argc):
|
---|
806 | return -argc
|
---|
807 | def MAKE_CLOSURE(self, argc):
|
---|
808 | # XXX need to account for free variables too!
|
---|
809 | return -argc
|
---|
810 | def BUILD_SLICE(self, argc):
|
---|
811 | if argc == 2:
|
---|
812 | return -1
|
---|
813 | elif argc == 3:
|
---|
814 | return -2
|
---|
815 | def DUP_TOPX(self, argc):
|
---|
816 | return argc
|
---|
817 |
|
---|
818 | findDepth = StackDepthTracker().findDepth
|
---|