[PATCH] [analyzer] Enable usage of temporaries in InitListExprs

[Pavel Labath]

+ kremenek at apple.com

Original patch was made by Ted, but I couldn't find his username on the
differential website thingy.


On 8 August 2013 16:51, Pavel Labath <labath at google.com> wrote:

> Hi jordan_rose,
>
> ExprEngine had code which specificaly disabled using CXXTempObjectRegions
> in
> InitListExprs. This was a hack put in r168757 to silence a false positive.
>
> The underlying problem seems to have been fixed in the mean time, as
> removing
> this code doesn't seem to break anything. Therefore I propose to remove it
> and
> solve PR16629 in the process.
>
> http://llvm-reviews.chandlerc.com/D1325
>
> Files:
>   lib/StaticAnalyzer/Core/ExprEngineC.cpp
>   test/Analysis/temporaries.cpp
>
> Index: lib/StaticAnalyzer/Core/ExprEngineC.cpp
> ===================================================================
> --- lib/StaticAnalyzer/Core/ExprEngineC.cpp
> +++ lib/StaticAnalyzer/Core/ExprEngineC.cpp
> @@ -596,8 +596,6 @@
>      for (InitListExpr::const_reverse_iterator it = IE->rbegin(),
>           ei = IE->rend(); it != ei; ++it) {
>        SVal V = state->getSVal(cast<Expr>(*it), LCtx);
> -      if (dyn_cast_or_null<CXXTempObjectRegion>(V.getAsRegion()))
> -        V = UnknownVal();
>        vals = getBasicVals().consVals(V, vals);
>      }
>
> Index: test/Analysis/temporaries.cpp
> ===================================================================
> --- test/Analysis/temporaries.cpp
> +++ test/Analysis/temporaries.cpp
> @@ -157,3 +157,39 @@
>    clang_analyzer_eval(threadDirectRef.value == 42); //
> expected-warning{{TRUE}}
>  #endif
>  }
> +
> +namespace PR16629 {
> +  struct A {
> +    explicit A(int* p_) : p(p_) {}
> +    int* p;
> +  };
> +
> +  extern void escape(const A*[]);
> +  extern void check(int);
> +
> +  void callEscape(const A& a) {
> +    const A* args[] = { &a };
> +    escape(args);
> +  }
> +
> +  void testNoWarning() {
> +    int x;
> +    callEscape(A(&x));
> +    check(x); // Analyzer used to give a "x is uninitialized warning" here
> +  }
> +
> +  void set(const A*a[]) {
> +    *a[0]->p = 47;
> +  }
> +
> +  void callSet(const A& a) {
> +    const A* args[] = { &a };
> +    set(args);
> +  }
> +
> +  void testConsistency() {
> +    int x;
> +    callSet(A(&x));
> +    clang_analyzer_eval(x == 47); // expected-warning{{TRUE}}
> +  }
> +}
>
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