[cfe-commits] r130781 - in /cfe/trunk: include/clang/Basic/DiagnosticSemaKinds.td lib/Sema/SemaChecking.cpp test/SemaCXX/warn-non-pod-memset.cpp

[Douglas Gregor]

On May 3, 2011, at 1:14 PM, Nico Weber wrote:

> Cool!
> 
> Can the warning mention "overwrites vtable" somehow? I think this is
> not immediately obvious from the diagnostic.

Sure, I'll make this wording tweak in the next commit.

	- Doug

> On Tue, May 3, 2011 at 1:05 PM, Douglas Gregor <dgregor at apple.com> wrote:
>> Author: dgregor
>> Date: Tue May  3 15:05:22 2011
>> New Revision: 130781
>> 
>> URL: http://llvm.org/viewvc/llvm-project?rev=130781&view=rev
>> Log:
>> Separate the -Wnon-pod-memset warnings into two separate warnings:
>>  - a default-on warning for pointers to dynamic classes (= classes with vtables)
>>  - a default-off warning for other non-POD types
>> 
>> 
>> Modified:
>>    cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
>>    cfe/trunk/lib/Sema/SemaChecking.cpp
>>    cfe/trunk/test/SemaCXX/warn-non-pod-memset.cpp
>> 
>> Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=130781&r1=130780&r2=130781&view=diff
>> ==============================================================================
>> --- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
>> +++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Tue May  3 15:05:22 2011
>> @@ -261,6 +261,9 @@
>>  def err_types_compatible_p_in_cplusplus : Error<
>>   "__builtin_types_compatible_p is not valid in C++">;
>>  def warn_builtin_unknown : Warning<"use of unknown builtin %0">, DefaultError;
>> +def warn_dyn_class_memset : Warning<
>> +  "destination for this memset call is a pointer to a dynamic class %0">,
>> +  InGroup<DiagGroup<"non-pod-memset">>;
>>  def warn_non_pod_memset : Warning<
>>   "destination for this memset call is a pointer to a non-POD type %0">,
>>   InGroup<DiagGroup<"non-pod-memset">>, DefaultIgnore;
>> 
>> Modified: cfe/trunk/lib/Sema/SemaChecking.cpp
>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaChecking.cpp?rev=130781&r1=130780&r2=130781&view=diff
>> ==============================================================================
>> --- cfe/trunk/lib/Sema/SemaChecking.cpp (original)
>> +++ cfe/trunk/lib/Sema/SemaChecking.cpp Tue May  3 15:05:22 2011
>> @@ -1799,6 +1799,17 @@
>> 
>>  //===--- CHECK: Standard memory functions ---------------------------------===//
>> 
>> +/// \brief Determine whether the given type is a dynamic class type (e.g.,
>> +/// whether it has a vtable).
>> +static bool isDynamicClassType(QualType T) {
>> +  if (CXXRecordDecl *Record = T->getAsCXXRecordDecl())
>> +    if (CXXRecordDecl *Definition = Record->getDefinition())
>> +      if (Definition->isDynamicClass())
>> +        return true;
>> +
>> +  return false;
>> +}
>> +
>>  /// \brief Check for dangerous or invalid arguments to memset().
>>  ///
>>  /// This issues warnings on known problematic or dangerous or unspecified
>> @@ -1814,27 +1825,26 @@
>> 
>>   const Expr *Dest = Call->getArg(0)->IgnoreParenImpCasts();
>> 
>> -  // The type checking for this warning is moderately expensive, only do it
>> -  // when enabled.
>> -  if (getDiagnostics().getDiagnosticLevel(diag::warn_non_pod_memset,
>> -                                          Dest->getExprLoc()) ==
>> -      Diagnostic::Ignored)
>> -    return;
>> -
>>   QualType DestTy = Dest->getType();
>>   if (const PointerType *DestPtrTy = DestTy->getAs<PointerType>()) {
>>     QualType PointeeTy = DestPtrTy->getPointeeType();
>>     if (PointeeTy->isVoidType())
>>       return;
>> 
>> +    unsigned DiagID = 0;
>> +    // Always complain about dynamic classes.
>> +    if (isDynamicClassType(PointeeTy))
>> +      DiagID = diag::warn_dyn_class_memset;
>>     // Check the C++11 POD definition regardless of language mode; it is more
>> -    // relaxed than earlier definitions and we don't want spurrious warnings.
>> -    if (PointeeTy->isCXX11PODType())
>> +    // relaxed than earlier definitions and we don't want spurious warnings.
>> +    else if (!PointeeTy->isCXX11PODType())
>> +      DiagID = diag::warn_non_pod_memset;
>> +    else
>>       return;
>> 
>>     DiagRuntimeBehavior(
>>       Dest->getExprLoc(), Dest,
>> -      PDiag(diag::warn_non_pod_memset)
>> +      PDiag(DiagID)
>>         << PointeeTy << Call->getCallee()->getSourceRange());
>> 
>>     SourceRange ArgRange = Call->getArg(0)->getSourceRange();
>> 
>> Modified: cfe/trunk/test/SemaCXX/warn-non-pod-memset.cpp
>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/warn-non-pod-memset.cpp?rev=130781&r1=130780&r2=130781&view=diff
>> ==============================================================================
>> --- cfe/trunk/test/SemaCXX/warn-non-pod-memset.cpp (original)
>> +++ cfe/trunk/test/SemaCXX/warn-non-pod-memset.cpp Tue May  3 15:05:22 2011
>> @@ -30,13 +30,13 @@
>>       // expected-warning {{destination for this memset call is a pointer to a non-POD type}} \
>>       // expected-note {{explicitly cast the pointer to silence this warning}}
>>   memset(&x3, 0, sizeof x3); // \
>> -      // expected-warning {{destination for this memset call is a pointer to a non-POD type}} \
>> +      // expected-warning {{destination for this memset call is a pointer to a dynamic class}} \
>>       // expected-note {{explicitly cast the pointer to silence this warning}}
>>   memset(&x4, 0, sizeof x4); // \
>>       // expected-warning {{destination for this memset call is a pointer to a non-POD type}} \
>>       // expected-note {{explicitly cast the pointer to silence this warning}}
>>   memset(&x5, 0, sizeof x5); // \
>> -      // expected-warning {{destination for this memset call is a pointer to a non-POD type}} \
>> +      // expected-warning {{destination for this memset call is a pointer to a dynamic class}} \
>>       // expected-note {{explicitly cast the pointer to silence this warning}}
>>  }
>> 
>> 
>> 
>> _______________________________________________
>> cfe-commits mailing list
>> cfe-commits at cs.uiuc.edu
>> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
>>