[cfe-commits] r142538 - in /cfe/trunk: lib/Sema/AnalysisBasedWarnings.cpp test/Sema/uninit-variables.c

[Matt Beaumont-Gay]

Hi Bill,

Can you merge this into the 3.0 branch? It fixes a minor diagnostic
regression introduced in r141881.

Thanks,
Matt

On Wed, Oct 19, 2011 at 11:53, Matt Beaumont-Gay <matthewbg at google.com> wrote:
> Author: matthewbg
> Date: Wed Oct 19 13:53:03 2011
> New Revision: 142538
>
> URL: http://llvm.org/viewvc/llvm-project?rev=142538&view=rev
> Log:
> Only warn at self-initialization if some later use is always uninitialized.
>
> Modified:
>    cfe/trunk/lib/Sema/AnalysisBasedWarnings.cpp
>    cfe/trunk/test/Sema/uninit-variables.c
>
> Modified: cfe/trunk/lib/Sema/AnalysisBasedWarnings.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/AnalysisBasedWarnings.cpp?rev=142538&r1=142537&r2=142538&view=diff
> ==============================================================================
> --- cfe/trunk/lib/Sema/AnalysisBasedWarnings.cpp (original)
> +++ cfe/trunk/lib/Sema/AnalysisBasedWarnings.cpp Wed Oct 19 13:53:03 2011
> @@ -586,9 +586,10 @@
>       // Specially handle the case where we have uses of an uninitialized
>       // variable, but the root cause is an idiomatic self-init.  We want
>       // to report the diagnostic at the self-init since that is the root cause.
> -      if (!vec->empty() && hasSelfInit)
> +      if (!vec->empty() && hasSelfInit && hasAlwaysUninitializedUse(vec))
>         DiagnoseUninitializedUse(S, vd, vd->getInit()->IgnoreParenCasts(),
> -                                 true, /* alwaysReportSelfInit */ true);
> +                                 /* isAlwaysUninit */ true,
> +                                 /* alwaysReportSelfInit */ true);
>       else {
>         // Sort the uses by their SourceLocations.  While not strictly
>         // guaranteed to produce them in line/column order, this will provide
> @@ -610,6 +611,16 @@
>     }
>     delete uses;
>   }
> +
> +private:
> +  static bool hasAlwaysUninitializedUse(const UsesVec* vec) {
> +  for (UsesVec::const_iterator i = vec->begin(), e = vec->end(); i != e; ++i) {
> +    if (i->second) {
> +      return true;
> +    }
> +  }
> +  return false;
> +}
>  };
>  }
>
>
> Modified: cfe/trunk/test/Sema/uninit-variables.c
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/uninit-variables.c?rev=142538&r1=142537&r2=142538&view=diff
> ==============================================================================
> --- cfe/trunk/test/Sema/uninit-variables.c (original)
> +++ cfe/trunk/test/Sema/uninit-variables.c Wed Oct 19 13:53:03 2011
> @@ -44,6 +44,15 @@
>   return x; // expected-warning{{variable 'x' may be uninitialized when used here}}
>  }
>
> +int test7b(int y) {
> +  int x = x; // expected-note{{variable 'x' is declared here}}
> +  if (y)
> +    x = 1;
> +  // Warn with "may be uninitialized" here (not "is uninitialized"), since the
> +  // self-initialization is intended to suppress a -Wuninitialized warning.
> +  return x; // expected-warning{{variable 'x' may be uninitialized when used here}}
> +}
> +
>  int test8(int y) {
>   int x;
>   if (y)
> @@ -415,4 +424,3 @@
>   for (; i < 10000; ++i) // expected-warning {{variable 'i' is uninitialized when used here}}
>     P[i] = 0.0f;
>  }
> -
>
>
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