1 | """
|
2 | pass_state.py
|
3 | """
|
4 | from __future__ import print_function
|
5 |
|
6 | import os
|
7 | from collections import defaultdict
|
8 |
|
9 | from mypy.types import Type
|
10 | from mypy.nodes import Expression
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11 |
|
12 | from mycpp.util import join_name, log, SymbolPath
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13 |
|
14 | from typing import Optional
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15 |
|
16 | _ = log
|
17 |
|
18 |
|
19 | class ModuleMember(object):
|
20 | """
|
21 | A member of a Python module.
|
22 |
|
23 | e.g. core.state.Mem => core::state::Mem
|
24 | """
|
25 |
|
26 | def __init__(self, module_path: SymbolPath, member: str) -> None:
|
27 | self.module_path = module_path
|
28 | self.member = member
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29 |
|
30 |
|
31 | class StaticObjectMember(object):
|
32 | """
|
33 | A static member of an object. Usually a a method like an alternative constructor.
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34 |
|
35 | e.g. runtime_asdl.Cell.CreateNull() => runtime_asdl::Cell::CreateNull()
|
36 | """
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37 |
|
38 | def __init__(self, base_type_name: SymbolPath, member: str) -> None:
|
39 | self.base_type_name = base_type_name
|
40 | self.member = member
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41 |
|
42 |
|
43 | class HeapObjectMember(object):
|
44 | """
|
45 | A member of a heap-allocated object.
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46 |
|
47 | e.g foo.empty() => foo->empty()
|
48 | """
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49 |
|
50 | def __init__(self, object_expr: Expression, object_type: Type,
|
51 | member: str) -> None:
|
52 | self.ojbect_expr = object_expr
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53 | self.object_type = object_type
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54 | self.member = member
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55 |
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56 |
|
57 | class StackObjectMember(object):
|
58 | """
|
59 | A member of a stack-allocated object.
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60 |
|
61 | e.g foo.empty() => foo.empty()
|
62 | """
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63 |
|
64 | def __init__(self, object_expr: Expression, object_type: Type,
|
65 | member: str) -> None:
|
66 | self.ojbect_expr = object_expr
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67 | self.object_type = object_type
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68 | self.member = member
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69 |
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70 |
|
71 | class Virtual(object):
|
72 | """Calculate which C++ methods need the virtual keyword.
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73 |
|
74 | See unit test for example usage.
|
75 | """
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76 |
|
77 | def __init__(self) -> None:
|
78 | self.methods: dict[SymbolPath, list[str]] = defaultdict(list)
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79 | self.subclasses: dict[SymbolPath, list[tuple[str]]] = defaultdict(list)
|
80 | self.virtuals: dict[tuple[SymbolPath, str], Optional[tuple[SymbolPath,
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81 | str]]] = {}
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82 | self.has_vtable: dict[SymbolPath, bool] = {}
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83 | self.can_reorder_fields: dict[SymbolPath, bool] = {}
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84 |
|
85 | # _Executor -> vm::_Executor
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86 | self.base_class_unique: dict[str, SymbolPath] = {}
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87 |
|
88 | # These are called on the Forward Declare pass
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89 | def OnMethod(self, class_name: SymbolPath, method_name: str) -> None:
|
90 | #log('OnMethod %s %s', class_name, method_name)
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91 |
|
92 | # __init__ and so forth don't count
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93 | if method_name.startswith('__') and method_name.endswith('__'):
|
94 | return
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95 |
|
96 | self.methods[class_name].append(method_name)
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97 |
|
98 | def OnSubclass(self, base_class: SymbolPath, subclass: SymbolPath) -> None:
|
99 | if len(base_class) > 1:
|
100 | # Hack for
|
101 | #
|
102 | # class _Executor: pass
|
103 | # versus
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104 | # class MyExecutor(vm._Executor): pass
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105 | base_key = base_class[-1]
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106 |
|
107 | # Fail if we have two base classes in different namespaces with the same
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108 | # name.
|
109 | if base_key in self.base_class_unique:
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110 | # Make sure we don't have collisions
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111 | assert (self.base_class_unique[base_key] == base_class or
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112 | base_class
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113 | in self.subclasses[self.base_class_unique[base_key]]
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114 | ), base_class
|
115 | else:
|
116 | self.base_class_unique[base_key] = base_class
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117 |
|
118 | else:
|
119 | base_key = base_class
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120 |
|
121 | self.subclasses[base_class].append(subclass)
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122 |
|
123 | def Calculate(self) -> None:
|
124 | """Call this after the forward declare pass."""
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125 | for base_class, subclasses in self.subclasses.items():
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126 | self.can_reorder_fields[base_class] = False
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127 |
|
128 | for subclass in subclasses:
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129 | self.can_reorder_fields[subclass] = False
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130 |
|
131 | b_methods = self.methods[base_class]
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132 | s_methods = self.methods[subclass]
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133 | overlapping = set(b_methods) & set(s_methods)
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134 | for method in overlapping:
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135 | self.virtuals[(base_class, method)] = None
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136 | self.virtuals[(subclass, method)] = (base_class, method)
|
137 | if overlapping:
|
138 | self.has_vtable[base_class] = True
|
139 | self.has_vtable[subclass] = True
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140 |
|
141 | # These is called on the Decl pass
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142 | def IsVirtual(self, class_name: SymbolPath, method_name: str) -> bool:
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143 | return (class_name, method_name) in self.virtuals
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144 |
|
145 | def HasVTable(self, class_name: SymbolPath) -> bool:
|
146 | return class_name in self.has_vtable
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147 |
|
148 | def CanReorderFields(self, class_name: SymbolPath) -> bool:
|
149 | if class_name in self.can_reorder_fields:
|
150 | return self.can_reorder_fields[class_name]
|
151 | else:
|
152 | return True # by default they can be reordered
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153 |
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154 |
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155 | def SymbolPathToSouffle(p: SymbolPath) -> str:
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156 | if len(p) > 1:
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157 | return '$Member({}, {})'.format(join_name(p[:-1], delim='.'), p[-1])
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158 |
|
159 | return '$Variable({})'.format(p[0])
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160 |
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161 |
|
162 | class Fact(object):
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163 | """
|
164 | An abstract fact. These can be used to build up datalog programs.
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165 | """
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166 |
|
167 | def __init__(self) -> None:
|
168 | pass
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169 |
|
170 | def name(self) -> str:
|
171 | raise NotImplementedError()
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172 |
|
173 | def Generate(self, func: str, statement: int) -> str:
|
174 | raise NotImplementedError()
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175 |
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176 |
|
177 | class FunctionCall(Fact):
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178 |
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179 | def __init__(self, callee: str) -> None:
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180 | self.callee = callee
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181 |
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182 | def name(self) -> str:
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183 | return 'call'
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184 |
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185 | def Generate(self, func: str, statement: int) -> str:
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186 | return '{}\t{}\t{}\n'.format(func, statement, self.callee)
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187 |
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188 |
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189 | class Definition(Fact):
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190 | """
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191 | The definition of a variable. This corresponds to an allocation.
|
192 | """
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193 |
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194 | def __init__(self, variable: SymbolPath) -> None:
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195 | self.variable = variable
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196 |
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197 | def name(self) -> str:
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198 | return 'define'
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199 |
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200 | def Generate(self, func: str, statement: int) -> str:
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201 | return '{}\t{}\t{}\n'.format(func, statement,
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202 | SymbolPathToSouffle(self.variable))
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203 |
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204 |
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205 | class Assignment(Fact):
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206 | """
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207 | The assignment of one variable or object member to another.
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208 | """
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209 |
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210 | def __init__(self, lhs: SymbolPath, rhs: SymbolPath) -> None:
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211 | self.lhs = lhs
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212 | self.rhs = rhs
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213 |
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214 | def name(self) -> str:
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215 | return 'assign'
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216 |
|
217 | def Generate(self, func: str, statement: int) -> str:
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218 | return '{}\t{}\t{}\t{}\n'.format(func, statement,
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219 | SymbolPathToSouffle(self.lhs),
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220 | SymbolPathToSouffle(self.rhs))
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221 |
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222 |
|
223 | class ControlFlowGraph(object):
|
224 | """
|
225 | A simple control-flow graph.
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226 |
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227 | Every statement in the program is represented as a node in a graph with
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228 | unique a numeric ID. Control flow is represented as directed edges through
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229 | the graph. Loops can introduce back-edges. Every node in the graph will
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230 | satisfy at least one of the following conditions:
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231 |
|
232 | - Its indegree is at least one.
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233 |
|
234 | - Its outdegree is at least one.
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235 |
|
236 | For simple linear graphs all you need is the AddStatement method. For more
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237 | complex flows there is a set of context managers below to help simplify
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238 | construction.
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239 |
|
240 | - For branches-like statements (e.g. if- and try- statements) use
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241 | CfgBranchContext. It will take care of the details associated with
|
242 | stitching the different branches to statements in the next statement.
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243 |
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244 | - For loops, use CfgLoopContext. It will take care of adding back-edges
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245 | and connecting break statements to any statements that proceed the
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246 | loop.
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247 |
|
248 | - CfgBlockContext can be used for simple cases where you just want to
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249 | track the beginning and end of a sequence of statements.
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250 |
|
251 | Statements can carry annotations called facts, which are used as inputs to
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252 | datalog programs to perform dataflow diffrent kinds of dataflow analyses.
|
253 | To annotate a statement, use the AddFact method with any object that
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254 | implements the Fact interface.
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255 |
|
256 | See the unit tests in pass_state_test.py and the mycpp phase in
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257 | control_flow_pass.py for detailed examples of usage.
|
258 | """
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259 |
|
260 | def __init__(self) -> None:
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261 | self.statement_counter: int = 0
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262 | self.edges: set[tuple[int, int]] = set({})
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263 | self.block_stack: list[int] = []
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264 | self.predecessors: set[int] = set({})
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265 | self.deadends: set[int] = set({})
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266 |
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267 | # order doesn't actually matter here, but sets require elements to be
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268 | # hashable
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269 | self.facts: dict[int, list[Fact]] = defaultdict(list)
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270 |
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271 | def AddEdge(self, pred: int, succ: int) -> None:
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272 | """
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273 | Add a directed edge from pred to succ. If pred is a deadend, its
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274 | non-deadends will be used instead.
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275 | """
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276 | if pred in self.deadends:
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277 | for w in [u for (u, v) in self.edges if v == pred]:
|
278 | self.AddEdge(w, succ)
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279 | else:
|
280 | self.edges.add((pred, succ))
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281 |
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282 | def AddDeadend(self, statement: int):
|
283 | """
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284 | Mark a statement as a dead-end (e.g. return or continue).
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285 | """
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286 | self.deadends.add(statement)
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287 |
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288 | def AddStatement(self) -> int:
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289 | """
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290 | Add a new statement and return its ID.
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291 | """
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292 | if len(self.predecessors) == 0:
|
293 | if len(self.block_stack):
|
294 | self.predecessors.add(self.block_stack[-1])
|
295 | else:
|
296 | self.predecessors.add(self.statement_counter)
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297 |
|
298 | self.statement_counter += 1
|
299 | for pred in self.predecessors:
|
300 | self.AddEdge(pred, self.statement_counter)
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301 |
|
302 | self.predecessors = set({})
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303 |
|
304 | if len(self.block_stack):
|
305 | self.block_stack[-1] = self.statement_counter
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306 |
|
307 | return self.statement_counter
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308 |
|
309 | def AddFact(self, statement: int, fact: Fact) -> None:
|
310 | """
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311 | Annotate a statement with a fact.
|
312 | """
|
313 | self.facts[statement].append(fact)
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314 |
|
315 | def _PushBlock(self, begin: Optional[int] = None) -> int:
|
316 | """
|
317 | Start a block at the given statement ID. If a beginning statement isn't
|
318 | provided one will be created and its ID will be returend.
|
319 |
|
320 | Direct use of this function is discouraged. Consider using one of the
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321 | block context managers below instead.
|
322 | """
|
323 | if begin is None:
|
324 | begin = self.AddStatement()
|
325 | else:
|
326 | self.predecessors.add(begin)
|
327 |
|
328 | self.block_stack.append(begin)
|
329 | return begin
|
330 |
|
331 | def _PopBlock(self) -> int:
|
332 | """
|
333 | Pop a block from the top of the stack and return the ID of the block's
|
334 | last statement.
|
335 |
|
336 | Direct use of this function is discouraged. Consider using one of the
|
337 | block context managers below instead.
|
338 | """
|
339 | assert len(self.block_stack)
|
340 | last = self.block_stack.pop()
|
341 | if len(self.block_stack) and last not in self.deadends:
|
342 | self.block_stack[-1] = last
|
343 |
|
344 | return last
|
345 |
|
346 |
|
347 | class CfgBlockContext(object):
|
348 | """
|
349 | Context manager to make dealing with things like with-statements easier.
|
350 | """
|
351 |
|
352 | def __init__(self,
|
353 | cfg: ControlFlowGraph,
|
354 | begin: Optional[int] = None) -> None:
|
355 | self.cfg = cfg
|
356 | if cfg is None:
|
357 | return
|
358 |
|
359 | self.entry = self.cfg._PushBlock(begin)
|
360 | self.exit = self.entry
|
361 |
|
362 | def __enter__(self) -> None:
|
363 | return self if self.cfg else None
|
364 |
|
365 | def __exit__(self, *args) -> None:
|
366 | if not self.cfg:
|
367 | return
|
368 |
|
369 | self.exit = self.cfg._PopBlock()
|
370 |
|
371 |
|
372 | class CfgBranchContext(object):
|
373 | """
|
374 | Context manager to make dealing with if-else blocks easier.
|
375 | """
|
376 |
|
377 | def __init__(self, cfg: ControlFlowGraph, branch_point: int) -> None:
|
378 | self.cfg = cfg
|
379 | self.entry = branch_point
|
380 | self.exit = self.entry
|
381 | if cfg is None:
|
382 | return
|
383 |
|
384 | self.arms = []
|
385 | self.pushed = False
|
386 |
|
387 | def AddBranch(self, entry: Optional[int] = None):
|
388 | if not self.cfg:
|
389 | return CfgBranchContext(None, None)
|
390 |
|
391 | self.arms.append(CfgBranchContext(self.cfg, entry or self.entry))
|
392 | self.cfg._PushBlock(self.arms[-1].entry)
|
393 | self.arms[-1].pushed = True
|
394 | return self.arms[-1]
|
395 |
|
396 | def __enter__(self) -> None:
|
397 | return self
|
398 |
|
399 | def __exit__(self, *args) -> None:
|
400 | if not self.cfg:
|
401 | return
|
402 |
|
403 | if self.pushed:
|
404 | self.exit = self.cfg._PopBlock()
|
405 |
|
406 | for arm in self.arms:
|
407 | if arm.exit not in self.cfg.deadends:
|
408 | self.cfg.predecessors.add(arm.exit)
|
409 |
|
410 |
|
411 | class CfgLoopContext(object):
|
412 | """
|
413 | Context manager to make dealing with loops easier.
|
414 | """
|
415 |
|
416 | def __init__(self,
|
417 | cfg: ControlFlowGraph,
|
418 | entry: Optional[int] = None) -> None:
|
419 | self.cfg = cfg
|
420 | self.breaks = set({})
|
421 | if cfg is None:
|
422 | return
|
423 |
|
424 | self.entry = self.cfg._PushBlock(entry)
|
425 | self.exit = self.entry
|
426 |
|
427 | def AddBreak(self, statement: int) -> None:
|
428 | assert self.cfg
|
429 | self.breaks.add(statement)
|
430 | self.cfg.AddDeadend(statement)
|
431 |
|
432 | def AddContinue(self, statement: int) -> None:
|
433 | self.cfg.AddEdge(statement, self.entry)
|
434 | self.cfg.AddDeadend(statement)
|
435 |
|
436 | def __enter__(self) -> None:
|
437 | return self if self.cfg else None
|
438 |
|
439 | def __exit__(self, *args) -> None:
|
440 | if not self.cfg:
|
441 | return
|
442 |
|
443 | self.exit = self.cfg._PopBlock()
|
444 | self.cfg.AddEdge(self.exit, self.entry)
|
445 | for pred in self.cfg.predecessors:
|
446 | self.cfg.AddEdge(pred, self.entry)
|
447 |
|
448 | # If we had any breaks, arm the predecessor set with the current
|
449 | # statement and the break statements.
|
450 | if len(self.breaks):
|
451 | if len(self.cfg.block_stack):
|
452 | self.cfg.predecessors.add(self.cfg.block_stack[-1])
|
453 | else:
|
454 | self.cfg.predecessors.add(self.cfg.statement_counter)
|
455 |
|
456 | for b in self.breaks:
|
457 | self.cfg.deadends.remove(b)
|
458 | self.cfg.predecessors.add(b)
|
459 |
|
460 |
|
461 | def DumpControlFlowGraphs(cfgs: dict[str, ControlFlowGraph],
|
462 | facts_dir='_tmp/mycpp-facts') -> None:
|
463 | """
|
464 | Dump the given control flow graphs and associated facts into the given
|
465 | directory as text files that can be consumed by datalog.
|
466 | """
|
467 | edge_facts = '{}/cf_edge.facts'.format(facts_dir)
|
468 | fact_files = {}
|
469 | os.makedirs(facts_dir, exist_ok=True)
|
470 | with open(edge_facts, 'w') as cfg_f:
|
471 | for func, cfg in sorted(cfgs.items()):
|
472 | joined = join_name(func, delim='.')
|
473 | for (u, v) in sorted(cfg.edges):
|
474 | cfg_f.write('{}\t{}\t{}\n'.format(joined, u, v))
|
475 |
|
476 | for statement, facts in sorted(cfg.facts.items()):
|
477 | for fact in facts: # already sorted temporally
|
478 | fact_f = fact_files.get(fact.name())
|
479 | if not fact_f:
|
480 | fact_f = open(
|
481 | '{}/{}.facts'.format(facts_dir, fact.name()), 'w')
|
482 | fact_files[fact.name()] = fact_f
|
483 |
|
484 | fact_f.write(fact.Generate(joined, statement))
|
485 |
|
486 | for f in fact_files.values():
|
487 | f.close()
|