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11c71fdd18
This commit removes SSA nodes from the data flow graph. Specifically, for a definition and use such as ```python x = expr y = x + 2 ``` we used to have flow from `expr` to an SSA variable representing x and from that SSA variable to the use of `x` in the definition of `y`. Now we instead have flow from `expr` to the control flow node for `x` at line 1 and from there to the control flow node for `x` at line 2. Specific changes: - `EssaNode` from the data flow layer no longer exists. - Several glue steps between `EssaNode`s and `CfgNode`s have been deleted. - Entry nodes are now admitted as `CfgNodes` in the data flow layer (they were filtered out before). - Entry nodes now have a new `toString` taking into account that the module name may be ambigous. - Some tests have been rewritten to accomodate the changes, but only `python/ql/test/experimental/dataflow/basic/maximalFlowsConfig.qll` should have semantic changes. - Comments have been updated - Test output has been updated, but apart from `python/ql/test/experimental/dataflow/basic/maximalFlows.expected` only `python/ql/test/experimental/dataflow/typetracking-summaries/summaries.py` should have a semantic change. This is a bonus fix, probably meaning that something was never connected up correctly.
48 lines
1.6 KiB
Plaintext
48 lines
1.6 KiB
Plaintext
import python
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import semmle.python.dataflow.new.DataFlow
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private import semmle.python.dataflow.new.internal.DataFlowPrivate as DataFlowPrivate
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/** Gets the EssaNode that holds the module imported by the fully qualified module name `name` */
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DataFlow::CfgNode module_import(string name) {
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// exists(Variable var, Import imp, Alias alias |
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// alias = imp.getAName() and
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// alias.getAsname() = var.getAStore() and
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// (
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// name = alias.getValue().(ImportMember).getImportedModuleName()
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// or
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// name = alias.getValue().(ImportExpr).getImportedModuleName()
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// ) and
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// result.getVar().(AssignmentDefinition).getSourceVariable() = var
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// )
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exists(Variable var, AssignmentDefinition def, Import imp, Alias alias |
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var = def.getSourceVariable() and
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result.getNode() = def.getDefiningNode() and
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alias = imp.getAName() and
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alias.getAsname() = var.getAStore()
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name = alias.getValue().(ImportMember).getImportedModuleName()
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or
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name = alias.getValue().(ImportExpr).getImportedModuleName()
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)
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}
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query predicate os_import(DataFlow::Node node) {
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node = module_import("os") and
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exists(node.getLocation().getFile().getRelativePath())
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}
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query predicate flowstep(DataFlow::Node nodeFrom, DataFlow::Node nodeTo) {
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os_import(nodeFrom) and
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DataFlow::localFlowStep(nodeFrom, nodeTo)
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}
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query predicate jumpStep(DataFlow::Node nodeFrom, DataFlow::Node nodeTo) {
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os_import(nodeFrom) and
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DataFlowPrivate::jumpStep(nodeFrom, nodeTo)
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}
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query predicate essaFlowStep(DataFlow::Node nodeFrom, DataFlow::Node nodeTo) {
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os_import(nodeFrom) and
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DataFlowPrivate::LocalFlow::localFlowStep(nodeFrom, nodeTo)
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}
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