[cfe-commits] r149359 - in /cfe/trunk: lib/Sema/SemaChecking.cpp test/Sema/conversion-64-32.c

[Eli Friedman]

On Mon, Jan 30, 2012 at 10:27 PM, Ted Kremenek <kremenek at apple.com> wrote:
> Nothing particularly special.  There is a performance cost to doing this, so I was being frugal on how inclusive this should be.  We can always adjust later if users ask for it.  Do you feel strongly about pulling all -Wconversion warnings in?

It just seems like it might be confusing if someone requests
-Wconversion and gets most, but not all, the -Wconversion warnings.
Probably not a big deal.

-Eli

> On Jan 30, 2012, at 9:50 PM, Eli Friedman wrote:
>
>> On Mon, Jan 30, 2012 at 9:37 PM, Ted Kremenek <kremenek at apple.com> wrote:
>>> Author: kremenek
>>> Date: Mon Jan 30 23:37:48 2012
>>> New Revision: 149359
>>>
>>> URL: http://llvm.org/viewvc/llvm-project?rev=149359&view=rev
>>> Log:
>>> Don't warn about -Wshorten-64-to-32 in unreachable code.  Fixes <rdar://problem/10759934>.  Apparently this is a common idiom in Linux (among other places).
>>>
>>> Modified:
>>>    cfe/trunk/lib/Sema/SemaChecking.cpp
>>>    cfe/trunk/test/Sema/conversion-64-32.c
>>>
>>> Modified: cfe/trunk/lib/Sema/SemaChecking.cpp
>>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaChecking.cpp?rev=149359&r1=149358&r2=149359&view=diff
>>> ==============================================================================
>>> --- cfe/trunk/lib/Sema/SemaChecking.cpp (original)
>>> +++ cfe/trunk/lib/Sema/SemaChecking.cpp Mon Jan 30 23:37:48 2012
>>> @@ -3693,15 +3693,24 @@
>>>
>>>  /// Diagnose an implicit cast;  purely a helper for CheckImplicitConversion.
>>>  static void DiagnoseImpCast(Sema &S, Expr *E, QualType SourceType, QualType T,
>>> -                            SourceLocation CContext, unsigned diag) {
>>> +                            SourceLocation CContext, unsigned diag,
>>> +                            bool pruneControlFlow = false) {
>>> +  if (pruneControlFlow) {
>>> +    S.DiagRuntimeBehavior(E->getExprLoc(), E,
>>> +                          S.PDiag(diag)
>>> +                            << SourceType << T << E->getSourceRange()
>>> +                            << SourceRange(CContext));
>>> +    return;
>>> +  }
>>>   S.Diag(E->getExprLoc(), diag)
>>>     << SourceType << T << E->getSourceRange() << SourceRange(CContext);
>>>  }
>>>
>>>  /// Diagnose an implicit cast;  purely a helper for CheckImplicitConversion.
>>>  static void DiagnoseImpCast(Sema &S, Expr *E, QualType T,
>>> -                            SourceLocation CContext, unsigned diag) {
>>> -  DiagnoseImpCast(S, E, E->getType(), T, CContext, diag);
>>> +                            SourceLocation CContext, unsigned diag,
>>> +                            bool pruneControlFlow = false) {
>>> +  DiagnoseImpCast(S, E, E->getType(), T, CContext, diag, pruneControlFlow);
>>>  }
>>>
>>>  /// Diagnose an implicit cast from a literal expression. Does not warn when the
>>> @@ -3907,7 +3916,8 @@
>>>       return;
>>>
>>>     if (SourceRange.Width == 64 && TargetRange.Width == 32)
>>> -      return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_64_32);
>>> +      return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_64_32,
>>> +                             /* pruneControlFlow */ true);
>>>     return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_precision);
>>>   }
>>
>> Why is -Wshorten-64-to-32 special here?  Why not suppress all
>> -Wconversion warnings in unreachable code?
>>
>> -Eli
>