[cfe-dev] : Clang Static Code Analyzer does not report 'Switch' Statement as a branch condition.

[Prashant Purohit]

Hi Jordan,

Thanks for the reply.
As suggested by you, I tried getting the switch statement using check::PreStmt<SwitchStmt>
But it is still failing, please find the below code which I added to get switch statement:

void SimpleChecker::checkPreStmt(const SwitchStmt *SW, CheckerContext &C ) const {
  // Print when a switch statement is found.
  llvm::errs() << "Switch Statement found.\n";
}

The above implementation is failing for a simple 'C' code mentioned below:
int main() {
    int var1 = 1, var2 = 2;
    switch(var1) {
        case 1:
            var1 = var2 + var1;
            break;
        default:
            break;
    }
    return 0;
}
It is not printing "Switch Statement found" on the console for above code.

Kindly suggest if I am missing something.

Thanks,
Prashant S. Purohit

From: Jordan Rose [mailto:jordan_rose at apple.com]
Sent: 03 December 2013 23:02
To: Prashant Purohit
Cc: cfe-dev at cs.uiuc.edu; Anna Zaks
Subject: Re: [cfe-dev] : Clang Static Code Analyzer does not report 'Switch' Statement as a branch condition.

Hi, Prashant. check::BranchCondition is only intended to be used for boolean branches, since the first argument is the conditional expression used for branching.* With a switch statement, that no longer makes sense. That said, you're right that there's currently no callback for a switch statement. The right thing to do here is probably to run pre-statement checks on the terminator statement in the CFG when it's not a logical expression or conditional expression, so that the nomal check::PreStmt<SwitchStmt> would work.

Please file a bug at llvm.org/bugs/<http://llvm.org/bugs/>, or alternately submit a patch to cfe-commits at cs.uiuc.edu<mailto:cfe-commits at cs.uiuc.edu> for review (and CC me or Anna).

Sorry for the trouble,
Jordan

* Implementation detail: it's a Stmt, not an Expr, because we stash the branch info for an Objective-C for-in loop on the loop statement itself. But it's still a boolean value.



On Nov 28, 2013, at 5:04 , Prashant Purohit <Prashant.Purohit at kpit.com<mailto:Prashant.Purohit at kpit.com>> wrote:


Hi all,

I am new to Clang Static Code analyzer internals.

Currently, I am trying to get all the branch conditions in a function using 'check::BranchCondition' call back function.
I am successful in detecting all the branch conditions like if, while, do..while, for and ternary operator condition except switch condition.

I have checked this with already existing checks (e.g.- DumpTraversal) which uses 'check::BranchCondition' call back function, these checks
also do not detect 'switch' statements.

Kindly help me in getting switch statements using 'check::BranchCondition' call back function.

Thanks,
Prashant S. Purohit
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