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C++: Simplify defDependsOnDef for AssignOperation

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These cases were unnecessarily transitive. There is no need for
`defDependsOnDef` to be transitive since that's handled in
`defDependsOnDefTransitively`.

The dependency information from the LHS of an `AssignmentOperation` is
now deduced the say way as the information from the RHS: by calling
`exprDependsOnDef`. This should effectively give us the same information
and recursion structure as if the operation (`x += e`) were desugared
(`x = x + e`).
This commit is contained in:
Jonas Jensen
2020-08-17 10:58:45 +02:00
parent fe72b559d3
commit edc5e5fbcf
1 changed files with 10 additions and 16 deletions
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26
cpp/ql/src/semmle/code/cpp/rangeanalysis/SimpleRangeAnalysis.qll
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@@ -239,33 +239,27 @@ private predicate defDependsOnDef(
// Definitions with a defining value.
exists(Expr expr | assignmentDef(def, v, expr) | exprDependsOnDef(expr, srcDef, srcVar))
or
exists(AssignAddExpr assignAdd, RangeSsaDefinition nextDef |
exists(AssignAddExpr assignAdd |
def = assignAdd and
assignAdd.getLValue() = nextDef.getAUse(v)
|
defDependsOnDef(nextDef, v, srcDef, srcVar) or
exprDependsOnDef(assignAdd.getRValue(), srcDef, srcVar)
def.getAVariable() = v and
exprDependsOnDef(assignAdd.getAnOperand(), srcDef, srcVar)
)
or
exists(AssignSubExpr assignSub, RangeSsaDefinition nextDef |
exists(AssignSubExpr assignSub |
def = assignSub and
assignSub.getLValue() = nextDef.getAUse(v)
|
defDependsOnDef(nextDef, v, srcDef, srcVar) or
exprDependsOnDef(assignSub.getRValue(), srcDef, srcVar)
def.getAVariable() = v and
exprDependsOnDef(assignSub.getAnOperand(), srcDef, srcVar)
)
or
exists(UnsignedAssignMulExpr assignMul, RangeSsaDefinition nextDef |
exists(UnsignedAssignMulExpr assignMul |
def = assignMul and
assignMul.getLValue() = nextDef.getAUse(v)
|
defDependsOnDef(nextDef, v, srcDef, srcVar) or
exprDependsOnDef(assignMul.getRValue(), srcDef, srcVar)
def.getAVariable() = v and
exprDependsOnDef(assignMul.getAnOperand(), srcDef, srcVar)
)
or
exists(CrementOperation crem |
def = crem and
crem.getOperand() = v.getAnAccess() and
def.getAVariable() = v and
exprDependsOnDef(crem.getOperand(), srcDef, srcVar)
)
or