[cfe-dev] check whether a `case` statement has a `break` statement?

[Nikola Smiljanic]

I was under the impression that he's trying to verify that every case has
an explicit break in order to enforce a coding standard that
forbids fall-through. But I might be wrong.

On Thu, Jan 3, 2013 at 4:36 AM, Matthieu Monrocq <matthieu.monrocq at gmail.com
> wrote:

> You do realize that if someone used a "return" or a "throw" then you will
> miss this ?
>
> -- Matthieu
>
> On Wed, Jan 2, 2013 at 10:15 AM, kevinlynx <kevinlynx at gmail.com> wrote:
>
>> I only want to know if there's a break between two cases (or between a
>> case and default). I dump a CastStmt AST, but not found a BreakStmt. That's
>> why i asked for help here.
>>
>>
>> ------------------ Original ------------------
>> *From: * "Alexander Kornienko"<alexfh at google.com>;
>> *Date: * Wed, Jan 2, 2013 10:17 AM
>> *To: * "kevinlynx"<kevinlynx at gmail.com>; **
>> *Cc: * "cfe-dev"<cfe-dev at cs.uiuc.edu>; **
>> *Subject: * Re: [cfe-dev] check whether a `case` statement has a `break`
>> statement?
>>
>> I guess you're trying to do something similar to -Wimplicit-fallthrough
>> diagnostics. If this is the case, take a look at
>> http://llvm.org/svn/llvm-project/cfe/trunk/lib/Sema/AnalysisBasedWarnings.cpp,
>> DiagnoseSwitchLabelsFallthrough function. In short: you can use CFG
>> (control-flow graph) to reason about execution paths, and, for example,
>> detect if there's an execution path between two case labels.
>>
>> If you need something simpler, and just detect if there's any 'break'
>> somewhere between two case labels (I'm not sure I understand why you would
>> need this, though), you can just use RecursiveASTVisitor and handle
>> SwitchStmt, SwitchCase (which can be either CaseStmt or DefaultStmt) and
>> BreakStmt.
>>
>> On Tue, Jan 1, 2013 at 3:30 PM, kevinlynx <kevinlynx at gmail.com> wrote:
>>
>>> In my parser, I get a `SwitchStmt`, and I can traverse all `case`
>>> statements of it. I want to check whether a `case` statement has a `break`
>>> statement.. But i can not figure it out. Here is my codes:
>>>
>>>
>>> for (SwitchCase *c = stmt->getSwitchCaseList(); c != NULL; c =
>>> c->getNextSwitchCase()) {
>>> if (isa<CaseStmt>(c)) {
>>> CaseStmt *caseStmt = cast<CaseStmt>(c)
>>> // I do not know how to check `CaseStmt` has a `BreakStmt`
>>> }
>>> }
>>>
>>> Thanks.
>>>
>>> BTW, I'm writing a static c code analyzer recently, this tool will check
>>> a number of c coding style rules for c codes. And because I'm a newbie to
>>> clang, so there will be more newbie questions coming, i'm sorry if i bother
>>> you guys.
>>>
>>>
>>
>> --
>> Regards,
>> Alexander Kornienko
>>
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>>
>
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