[llvm-commits] [llvm] r160170 - /llvm/trunk/include/llvm/Support/CommandLine.h

[Alexander Kornienko]

Ping.

On Mon, Jul 23, 2012 at 7:52 PM, Alexander Kornienko <alexfh at google.com>wrote:

> I've added a test that shows a condition when my patch helps.
> It fails under valgrind with rev 160170 reverted:
>
> $ svn merge -r 160170:160169 https://llvm.org/svn/llvm-project/llvm/trunk
> $ cd your-build-dir
> $ make check-all
> $ valgrind unittests/Support/SupportTests
> ...
> [ RUN      ] CommandLineTest.ParseEnvironmentToLocalVar
> ==12673== Conditional jump or move depends on uninitialised value(s)
> ==12673==    at 0x659A17:
> GetOptionInfo(llvm::SmallVectorImpl<llvm::cl::Option*>&,
> llvm::SmallVectorImpl<llvm::cl::Option*>&,
> llvm::StringMap<llvm::cl::Option*, llvm::MallocAllocator>&) (in
> /usr/local/google/users/alexfh/cmake-clang-build/unittests/Support/SupportTests)
> ==12673==    by 0x657E27: llvm::cl::ParseCommandLineOptions(int, char
> const* const*, char const*, bool) (in
> /usr/local/google/users/alexfh/cmake-clang-build/unittests/Support/SupportTests)
> ==12673==    by 0x657B70: llvm::cl::ParseEnvironmentOptions(char const*,
> char const*, char const*, bool) (in
> /usr/local/google/users/alexfh/cmake-clang-build/unittests/Support/SupportTests)
> ==12673==    by 0x495B2F: (anonymous
> namespace)::CommandLineTest_ParseEnvironmentToLocalVar_Test::TestBody() (in
> /usr/local/google/users/alexfh/cmake-clang-build/unittests/Support/SupportTests)
> ...
>
> With rev 160170 in place this valgrind message isn't triggered:
>
> $ svn revert include/llvm/Support/CommandLine.h
> $ cd your-build-dir
> $ make check-all
> $ valgrind unittests/Support/SupportTests
> ...
> [ RUN      ] CommandLineTest.ParseEnvironmentToLocalVar
> [       OK ] CommandLineTest.ParseEnvironmentToLocalVar (10 ms)
> ...
>
> There are also a few tests in tools/clang/tests/Tooling that fail on their
> own (i.e. without valgrind) without rev 160170, but these failures highly
> depend on external conditions and surrounding code layout (however,
> valgrind consistently finds issues even if the code doesn't break).
>
> Is it enough to prove validity of my previous patch?
>
>
> On Mon, Jul 16, 2012 at 3:28 PM, Chandler Carruth <chandlerc at google.com>wrote:
>
>> On Mon, Jul 16, 2012 at 6:24 AM, Alexander Kornienko <alexfh at google.com>wrote:
>>
>>> On Mon, Jul 16, 2012 at 3:10 PM, Chandler Carruth <chandlerc at google.com>wrote:
>>>
>>>> On Mon, Jul 16, 2012 at 6:02 AM, Alexander Kornienko <alexfh at google.com
>>>> > wrote:
>>>>
>>>>>
>>>>> On Fri, Jul 13, 2012 at 3:06 PM, Duncan Sands <baldrick at free.fr>wrote:
>>>>>
>>>>>> Hi Alexander,
>>>>>> > Initializers for some fields were missing in Option::Option
>>>>>>
>>>>>> did it matter?  If so, please add a testcase.  If not, why this
>>>>>> change?
>>>>>>
>>>>> This did matter. It caused random crashes in case cl::opt was a member
>>>>> of non-POD class.
>>>>>
>>>>
>>>> Hold on, a *member*? 'cl::opt' objects are supposed to be globals, not
>>>> members.
>>>>
>>> We need it as a member to make a class which handles a common subset of
>>> command-line options for several clang tools. In a close future we'll need
>>> a control on which options should be enabled and which not. So we can't do
>>> it with global variables. Why can't we use it as a member?
>>>
>>
>> Errr... Ok, this is something we should discuss in more depth.
>>
>> Essentially, it's not that you necessarily can't, it's that the library
>> was never designed with that use case in mind. It's completely outside the
>> contract of the library, and so random things are likely to continue
>> breaking. If this the correct design, we need to at least extend the
>> library with unittests to check its behavior in that context. These
>> unittests would then be what you would run under Valgrind in order to
>> detect the failure.
>>
>
>
>
> --
> Alexander Kornienko | Software Engineer | alexfh at google.com | +49 151 221
> 77 957
> Google Germany GmbH | Dienerstr. 12 | 80331 München
>
>


-- 
-- 
Best regards,
Alexander Kornienko
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