[cfe-commits] r86504 - in /cfe/trunk: lib/Analysis/CheckSizeofPointer.cpp test/Analysis/sizeofpointer.c

[Zhongxing Xu]

2009/11/10 Ted Kremenek <kremenek at apple.com>:
> Hi Zhongxing,
>
> I think the previous wording was more in the right direction as it explained
> the actual problem; "This can produce an unexpected result." is fairly
> content-free unless you already know what the warning is about.
>
> How about:
>
>  "Call to sizeof() returns the size of the pointer (X bytes) instead of how
> much memory has been allocated by malloc()"

I think sizeof() never return the memory allocated by malloc(). (CWE
is misleading) sizeof only returns the size of the object represented
by the expression.

>
> (where X bytes is filled in with the pointer size)
>
> On Nov 8, 2009, at 6:28 PM, Zhongxing Xu wrote:
>
>> Author: zhongxingxu
>> Date: Sun Nov  8 20:28:12 2009
>> New Revision: 86504
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=86504&view=rev
>> Log:
>> Add a test case for CWE-467, and simplify the wording of the warning.
>>
>> Added:
>>   cfe/trunk/test/Analysis/sizeofpointer.c
>> Modified:
>>   cfe/trunk/lib/Analysis/CheckSizeofPointer.cpp
>>
>> Modified: cfe/trunk/lib/Analysis/CheckSizeofPointer.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Analysis/CheckSizeofPointer.cpp?rev=86504&r1=86503&r2=86504&view=diff
>>
>>
>> ==============================================================================
>> --- cfe/trunk/lib/Analysis/CheckSizeofPointer.cpp (original)
>> +++ cfe/trunk/lib/Analysis/CheckSizeofPointer.cpp Sun Nov  8 20:28:12 2009
>> @@ -47,7 +47,7 @@
>>    SourceRange R = E->getArgumentExpr()->getSourceRange();
>>    BR.EmitBasicReport("Potential unintended use of sizeof() on pointer
>> type",
>>                       "Logic",
>> -                       "The code calls sizeof() on a malloced pointer
>> type, which always returns the wordsize/8. This can produce an unexpected
>> result if the programmer intended to determine how much memory has been
>> allocated.",
>> +                       "The code calls sizeof() on a pointer type. This
>> can produce an unexpected result.",
>>                       E->getLocStart(), &R, 1);
>>  }
>> }
>>
>> Added: cfe/trunk/test/Analysis/sizeofpointer.c
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/sizeofpointer.c?rev=86504&view=auto
>>
>>
>> ==============================================================================
>> --- cfe/trunk/test/Analysis/sizeofpointer.c (added)
>> +++ cfe/trunk/test/Analysis/sizeofpointer.c Sun Nov  8 20:28:12 2009
>> @@ -0,0 +1,8 @@
>> +// RUN: clang-cc -analyze -warn-sizeof-pointer -verify %s
>> +
>> +struct s {
>> +};
>> +
>> +int f(struct s *p) {
>> +  return sizeof(p); // expected-warning{{The code calls sizeof() on a
>> pointer type. This can produce an unexpected result.}}
>> +}
>>
>>
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>
>