[PATCH] D65287: [analyzer][CFG] Don't track the condition of asserts

[Kristóf Umann via Phabricator via cfe-commits]

Szelethus marked 2 inline comments as done.
Szelethus added a comment.

After testing this patch out, I'm confident it works pretty well. Take a look at the following two runs: 138 notes <http://cc.elte.hu:15001/GSoC2019-July-5/#is-unique=on&run=LLVM%2FClang%20WITH%20condition%20tracking%20FINAL&review-status=Confirmed&review-status=False%20positive&review-status=Intentional&detection-status=New&detection-status=Reopened&detection-status=Unresolved&tab=LLVM%2FClang%20WITH%20condition%20tracking%20FINAL&reportHash=27f8f44ceff3132c3a2232bb760804d8&report=7893&subtab=27f8f44ceff3132c3a2232bb760804d8> -> 20 notes <http://cc.elte.hu:15001/GSoC2019-July-5/#is-unique=on&run=LLVM%2FClang%20WITH%20condition%20tracking%20FINAL&review-status=Confirmed&review-status=False%20positive&review-status=Intentional&detection-status=New&detection-status=Reopened&detection-status=Unresolved&tab=LLVM%2FClang%20WITH%20condition%20tracking%20FINAL&reportHash=27f8f44ceff3132c3a2232bb760804d8&report=13010&subtab=27f8f44ceff3132c3a2232bb760804d8>.



================
Comment at: clang/lib/StaticAnalyzer/Core/BugReporterVisitors.cpp:1753-1755
+  // It so happens that CFGBlock::getTerminatorCondition returns 'A' for block
+  // B1, 'A && B' for B2, and 'A && B || C' for B3. Let's check whether we
+  // reached the end of the condition!
----------------
NoQ wrote:
> Szelethus wrote:
> > NoQ wrote:
> > > Clever trick, but why not match for logical operators directly? Something like this:
> > > ```lang=c++
> > > if (auto B = dyn_cast<BinaryOperator>(OuterCond))
> > >   if (B->isLogicalOp())
> > >     return isAssertlikeBlock(Else, Context);
> > > ```
> > What about `assert(a + b && "Shouldn't be zero!");`?
> Mmm, could you elaborate? >.<
```lang=c++
if (auto B = dyn_cast<BinaryOperator>(OuterCond))
  if (B->isLogicalOp())
    return isAssertlikeBlock(Else, Context);
```
We don't need `isLogicalOp()` here.

Also, I should probably have a testcase for the elvis operator (`?:`).


================
Comment at: clang/test/Analysis/track-control-dependency-conditions.cpp:469-471
+extern void __assert_fail (__const char *__assertion, __const char *__file,
+                           unsigned int __line, __const char *__function)
+__attribute__ ((__noreturn__));
----------------
NoQ wrote:
> Szelethus wrote:
> > NoQ wrote:
> > > I'm pretty sure you can define this function only once.
> > Note that it is in a namespace!
> I mean, why is it in a namespace? Why not just define it once for the whole file? It's not like you're gonna be trying out different variants of `__assert_fail`.
Yea, good point.


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  https://reviews.llvm.org/D65287/new/

https://reviews.llvm.org/D65287