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<p class="MsoNormal"><span style="color:#1F497D">I am writing a checker to check that a variable is given a value before it is accessed. So I created a checkLocation call-back:<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span style="color:#1F497D">void checkLocation(SVal L, bool IsLoad, const Stmt* S, CheckerContext &ChCtx) const {<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span style="color:#1F497D"> if (!IsLoad) return; // location value is not being accessed<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span style="color:#1F497D"> const MemRegion* MemReg = L.getAsRegion();<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span style="color:#1F497D"> if (!MemReg) return; // L is not a memory location<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span style="color:#1F497D"> const VarRegion* VarReg = MemReg->getAs<VarRegion>();<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span style="color:#1F497D"> if (!VarReg) return; // L is not a variable location<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span style="color:#1F497D"> SVal VarVal = ChCtx.getState()->getSVal(VarReg);<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span style="color:#1F497D"> if (VarVal.isUndef()) {<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span style="color:#1F497D"> // Variable value is undefined; report error<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span style="color:#1F497D"> EmitReport(S->getSourceRange(), ChCtx, “Variable may not have been assigned a value”);<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span style="color:#1F497D"> }<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span style="color:#1F497D">}<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">This works fine for scalar variables like ints, but I’ve discovered that a struct variable will be defined even if it hasn’t been given a value. So my plan is to check the struct fields to see if they’ve been
given values.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">My question is: are there other cases where VarVal.isUndef() will return false even though the variable has not been given a value?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Ray<o:p></o:p></span></p>
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