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Merge pull request #5928 from hvitved/python/type-tracker-split

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Python: Split up `(small)step` into intra/interprocedural predicates
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Tom Hvitved
2021-05-20 14:13:44 +02:00
committed by GitHub
parent 17afbdf258 1fc95a68ca
commit 2a7ceb2e19
1 changed files with 54 additions and 15 deletions
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69
python/ql/src/experimental/typetracking/TypeTracker.qll
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@@ -57,11 +57,60 @@ class StepSummary extends TStepSummary {
module StepSummary {
/**
* Gets the summary that corresponds to having taken a forwards
* heap and/or inter-procedural step from `nodeFrom` to `nodeTo`.
* heap and/or intra-procedural step from `nodeFrom` to `nodeTo`.
*
* Steps contained in this predicate should _not_ depend on the call graph.
*/
cached
private predicate stepNoCall(LocalSourceNode nodeFrom, LocalSourceNode nodeTo, StepSummary summary) {
exists(Node mid | nodeFrom.flowsTo(mid) and smallstepNoCall(mid, nodeTo, summary))
}
/**
* Gets the summary that corresponds to having taken a forwards
* inter-procedural step from `nodeFrom` to `nodeTo`.
*/
cached
private predicate stepCall(LocalSourceNode nodeFrom, LocalSourceNode nodeTo, StepSummary summary) {
exists(Node mid | nodeFrom.flowsTo(mid) and smallstepCall(mid, nodeTo, summary))
}
/**
* Gets the summary that corresponds to having taken a forwards
* heap and/or inter-procedural step from `nodeFrom` to `nodeTo`.
*
* This predicate is inlined, which enables better join-orders when
* the call graph construction and type tracking are mutually recursive.
* In such cases, non-linear recursion involving `step` will be limited
* to non-linear recursion for the parts of `step` that involve the
* call graph.
*/
pragma[inline]
predicate step(LocalSourceNode nodeFrom, LocalSourceNode nodeTo, StepSummary summary) {
exists(Node mid | nodeFrom.flowsTo(mid) and smallstep(mid, nodeTo, summary))
stepNoCall(nodeFrom, nodeTo, summary)
or
stepCall(nodeFrom, nodeTo, summary)
}
pragma[noinline]
private predicate smallstepNoCall(Node nodeFrom, LocalSourceNode nodeTo, StepSummary summary) {
jumpStep(nodeFrom, nodeTo) and
summary = LevelStep()
or
exists(string content |
localSourceStoreStep(nodeFrom, nodeTo, content) and
summary = StoreStep(content)
or
basicLoadStep(nodeFrom, nodeTo, content) and summary = LoadStep(content)
)
}
pragma[noinline]
private predicate smallstepCall(Node nodeFrom, LocalSourceNode nodeTo, StepSummary summary) {
callStep(nodeFrom, nodeTo) and summary = CallStep()
or
returnStep(nodeFrom, nodeTo) and
summary = ReturnStep()
}
/**
@@ -71,21 +120,11 @@ module StepSummary {
* Unlike `StepSummary::step`, this predicate does not compress
* type-preserving steps.
*/
pragma[inline]
predicate smallstep(Node nodeFrom, LocalSourceNode nodeTo, StepSummary summary) {
jumpStep(nodeFrom, nodeTo) and
summary = LevelStep()
smallstepNoCall(nodeFrom, nodeTo, summary)
or
callStep(nodeFrom, nodeTo) and summary = CallStep()
or
returnStep(nodeFrom, nodeTo) and
summary = ReturnStep()
or
exists(string content |
localSourceStoreStep(nodeFrom, nodeTo, content) and
summary = StoreStep(content)
or
basicLoadStep(nodeFrom, nodeTo, content) and summary = LoadStep(content)
)
smallstepCall(nodeFrom, nodeTo, summary)
}
/**