[libcxx] r222052 - Initialize pointer in string conversion helpers to prevent MSAN diagnostic.

[Evgeniy Stepanov]

On Wed Nov 19 2014 at 3:54:46 AM Eric Fiselier <eric at efcs.ca> wrote:

> It seems you are missing interceptors for wcstof, wcstod, and wcstold as
> well.
>
> Could this be responsible for PR21579 as well?
> http://llvm.org/bugs/show_bug.cgi?id=21579
>

Unlikely.


>
>
> /Eric
>
> On Tue, Nov 18, 2014 at 2:44 AM, Evgeniy Stepanov <eugenis at google.com>
> wrote:
>
>> We are missing interceptors for: wcstol, wcstoul, wcstoll, wcstoull.
>>
>> On Mon Nov 17 2014 at 11:02:13 PM Kostya Serebryany <kcc at google.com>
>> wrote:
>>
>>> if msan does not see what's goign on inside libc we need to teach it --
>>> it already has a bunch of libc interceptors, but clearly not all.
>>> Do you know what libc function is called here?
>>> Or how to reproduce the reports you've been seeing?
>>>
>>> On Fri, Nov 14, 2014 at 2:23 PM, Eric Fiselier <eric at efcs.ca> wrote:
>>>
>>>> Author: ericwf
>>>> Date: Fri Nov 14 16:23:57 2014
>>>> New Revision: 222052
>>>>
>>>> URL: http://llvm.org/viewvc/llvm-project?rev=222052&view=rev
>>>> Log:
>>>> Initialize pointer in string conversion helpers to prevent MSAN
>>>> diagnostic.
>>>>
>>>> Since the initialization of the pointer happens across the libc library
>>>> boundry
>>>> MSAN will not know the pointer was initialized. This fixes MSAN
>>>> failures in
>>>> test/strings/string.conversions.
>>>>
>>>> Modified:
>>>>     libcxx/trunk/src/string.cpp
>>>>
>>>> Modified: libcxx/trunk/src/string.cpp
>>>> URL:
>>>> http://llvm.org/viewvc/llvm-project/libcxx/trunk/src/string.cpp?rev=222052&r1=222051&r2=222052&view=diff
>>>>
>>>> ==============================================================================
>>>> --- libcxx/trunk/src/string.cpp (original)
>>>> +++ libcxx/trunk/src/string.cpp Fri Nov 14 16:23:57 2014
>>>> @@ -63,7 +63,7 @@ inline
>>>>  V
>>>>  as_integer_helper(const string& func, const S& str, size_t* idx, int
>>>> base, F f)
>>>>  {
>>>> -    typename S::value_type* ptr;
>>>> +    typename S::value_type* ptr = nullptr;
>>>>      const typename S::value_type* const p = str.c_str();
>>>>      typename remove_reference<decltype(errno)>::type errno_save =
>>>> errno;
>>>>      errno = 0;
>>>> @@ -180,7 +180,7 @@ inline
>>>>  V
>>>>  as_float_helper(const string& func, const S& str, size_t* idx, F f )
>>>>  {
>>>> -    typename S::value_type* ptr;
>>>> +    typename S::value_type* ptr = nullptr;
>>>>      const typename S::value_type* const p = str.c_str();
>>>>      typename remove_reference<decltype(errno)>::type errno_save =
>>>> errno;
>>>>      errno = 0;
>>>>
>>>>
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>>>>
>>>
>>>
>
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