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

[Ted Kremenek]

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?

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