r201165 - [Sema] Revert the change in r200622 that allowed integer casts to silence -Wnon-literal-null-conversion in C code.

[jahanian]

On Feb 11, 2014, at 9:53 AM, Argyrios Kyrtzidis <akyrtzi at gmail.com> wrote:

> Author: akirtzidis
> Date: Tue Feb 11 11:53:22 2014
> New Revision: 201165
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=201165&view=rev
> Log:
> [Sema] Revert the change in r200622 that allowed integer casts to silence -Wnon-literal-null-conversion in C code.
> 
> It is actually useful to warn in such cases, thanks to Dmitri for pushing on this and making us see the light!
> 
> Related to rdar://15925483 and rdar://15922612. The latter radar is where the usefulness of the warning is most clear.

People cannot read radars. Please provide content here.
- Fariborz

> 
> Modified:
>    cfe/trunk/lib/AST/Expr.cpp
>    cfe/trunk/test/Sema/warn-null.c
> 
> Modified: cfe/trunk/lib/AST/Expr.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/Expr.cpp?rev=201165&r1=201164&r2=201165&view=diff
> ==============================================================================
> --- cfe/trunk/lib/AST/Expr.cpp (original)
> +++ cfe/trunk/lib/AST/Expr.cpp Tue Feb 11 11:53:22 2014
> @@ -3061,9 +3061,6 @@ Expr::isNullPointerConstant(ASTContext &
>             Pointee->isVoidType() &&                              // to void*
>             CE->getSubExpr()->getType()->isIntegerType())         // from int.
>           return CE->getSubExpr()->isNullPointerConstant(Ctx, NPC);
> -      // Or an integer cast.
> -      } else if (CE->getType()->isIntegerType()) {
> -        return CE->getSubExpr()->isNullPointerConstant(Ctx, NPC);
>       }
>     }
>   } else if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(this)) {
> 
> Modified: cfe/trunk/test/Sema/warn-null.c
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/warn-null.c?rev=201165&r1=201164&r2=201165&view=diff
> ==============================================================================
> --- cfe/trunk/test/Sema/warn-null.c (original)
> +++ cfe/trunk/test/Sema/warn-null.c Tue Feb 11 11:53:22 2014
> @@ -1,6 +1,6 @@
> // RUN: %clang_cc1 %s -verify
> 
> -#define NLL (unsigned long long)0
> +#define SOME_ADDR (unsigned long long)0
> 
> // PR10837: Warn if a non-pointer-typed expression is folded to a null pointer
> int *p = 0;
> @@ -10,5 +10,5 @@ void f() {
>   p = 0;
>   q = '\0'; // expected-warning{{expression which evaluates to zero treated as a null pointer constant}}
>   r = 1 - 1; // expected-warning{{expression which evaluates to zero treated as a null pointer constant}}
> -  p = NLL;
> +  p = SOME_ADDR; // expected-warning{{expression which evaluates to zero treated as a null pointer constant}}
> }
> 
> 
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