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Merge pull request #3857 from jbj/flowthrough-bigstep-perf

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C++: Remove big-step relation in flow-through code
This commit is contained in:
Anders Schack-Mulligen
2020-07-01 14:23:23 +02:00
committed by GitHub
parent 50cd759718 cff0f48d34
commit 7d057598d8
4 changed files with 40 additions and 204 deletions
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61
csharp/ql/src/semmle/code/csharp/dataflow/internal/DataFlowImplCommon.qll
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@@ -147,54 +147,6 @@ private module Cached {
}
}
private module LocalFlowBigStep {
private predicate localFlowEntry(Node n) {
Cand::cand(_, n) and
(
n instanceof ParameterNode or
n instanceof OutNode or
readStep(_, _, n) or
n instanceof CastNode
)
}
private predicate localFlowExit(Node n) {
Cand::cand(_, n) and
(
n instanceof ArgumentNode
or
n instanceof ReturnNode
or
readStep(n, _, _)
or
n instanceof CastNode
or
n =
any(PostUpdateNode pun | Cand::parameterValueFlowsToPreUpdateCand(_, pun))
.getPreUpdateNode()
)
}
pragma[nomagic]
private predicate localFlowStepPlus(Node node1, Node node2) {
localFlowEntry(node1) and
simpleLocalFlowStep(node1, node2) and
node1 != node2
or
exists(Node mid |
localFlowStepPlus(node1, mid) and
simpleLocalFlowStep(mid, node2) and
not mid instanceof CastNode
)
}
pragma[nomagic]
predicate localFlowBigStep(Node node1, Node node2) {
localFlowStepPlus(node1, node2) and
localFlowExit(node2)
}
}
/**
* The final flow-through calculation:
*
@@ -234,7 +186,7 @@ private module Cached {
// local flow
exists(Node mid |
parameterValueFlow(p, mid, read) and
LocalFlowBigStep::localFlowBigStep(mid, node)
simpleLocalFlowStep(mid, node)
)
or
// read
@@ -246,16 +198,23 @@ private module Cached {
compatibleTypes(getNodeType(p), read.getContainerType())
)
or
parameterValueFlow0_0(TReadStepTypesNone(), p, node, read)
}
pragma[nomagic]
private predicate parameterValueFlow0_0(
ReadStepTypesOption mustBeNone, ParameterNode p, Node node, ReadStepTypesOption read
) {
// flow through: no prior read
exists(ArgumentNode arg |
parameterValueFlowArg(p, arg, TReadStepTypesNone()) and
parameterValueFlowArg(p, arg, mustBeNone) and
argumentValueFlowsThrough(arg, read, node)
)
or
// flow through: no read inside method
exists(ArgumentNode arg |
parameterValueFlowArg(p, arg, read) and
argumentValueFlowsThrough(arg, TReadStepTypesNone(), node)
argumentValueFlowsThrough(arg, mustBeNone, node)
)
}