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Use only_bind_out to force a good join order. #5851

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Merged
alexet merged 1 commit into from
May 19, 2021
Merged

Use only_bind_out to force a good join order. #5851

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3 changes: 2 additions & 1 deletion csharp/ql/src/semmle/code/csharp/dispatch/Dispatch.qll
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Original file line number Diff line number Diff line change
Expand Up @@ -387,7 +387,8 @@ private module Internal {
result = this.getAStaticTarget()
or
result.getUnboundDeclaration() =
this.getASubsumedStaticTarget0(Gvn::getGlobalValueNumber(result.getDeclaringType()))
this.getASubsumedStaticTarget0(pragma[only_bind_out](Gvn::getGlobalValueNumber(result
.getDeclaringType())))

@hvitved hvitved May 7, 2021

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How about instead changing

cached
GvnType getGlobalValueNumber(Type t) { ... }

to

cached
GvnType getGlobalValueNumberImpl(Type t) { ... }

pragma[inline]
GvnType getGlobalValueNumber(Type t) {
  result = pragma[only_bind_out](getGlobalValueNumberImpl(t))
}

in Unification.qll?

@alexet alexet May 7, 2021

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That seems to break other code. Specifically typeConstraintUnifiable/typeConstraintSubsumes in Unification.qll where we rely on doing getGlobalValueNumber backwards and forcing the optimiser not to do that makes the code awful. It looks we avoid blowup in those cases due to how small TTypeConstraint is.

@hvitved hvitved May 18, 2021

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OK, let's get this in now, and then I can investigate the other approach in a follow-up PR.

}

/**
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