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f07a7bf8cf
Will need subsequent PRs fixing up test failures (due to deprecated methods moving around), but other than that everything should be straight-forward.
40 lines
1.3 KiB
Plaintext
40 lines
1.3 KiB
Plaintext
import python
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private predicate empty_sequence(Expr e) {
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exists(SsaVariable var | var.getAUse().getNode() = e |
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empty_sequence(var.getDefinition().getNode())
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)
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or
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e instanceof List and not exists(e.(List).getAnElt())
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or
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e instanceof Tuple and not exists(e.(Tuple).getAnElt())
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or
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e.(StrConst).getText().length() = 0
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}
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/* This has the potential for refinement, but we err on the side of fewer false positives for now. */
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private predicate probably_non_empty_sequence(Expr e) { not empty_sequence(e) }
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/** A loop which probably defines v */
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private Stmt loop_probably_defines(Variable v) {
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exists(Name defn | defn.defines(v) and result.contains(defn) |
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probably_non_empty_sequence(result.(For).getIter())
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or
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probably_non_empty_sequence(result.(While).getTest())
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)
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}
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/** Holds if the variable used by `use` is probably defined in a loop */
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predicate probably_defined_in_loop(Name use) {
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exists(Stmt loop | loop = loop_probably_defines(use.getVariable()) |
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loop.getAFlowNode().strictlyReaches(use.getAFlowNode())
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)
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}
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/** Holds if `s` is a loop that probably executes at least once */
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predicate loop_probably_executes_at_least_once(Stmt s) {
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probably_non_empty_sequence(s.(For).getIter())
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or
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probably_non_empty_sequence(s.(While).getTest())
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}
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