[Qt-creator] Clang code model running in C++98 mode

[Julius Bullinger]

Hi Nikolai

On 06.11.2018 12:19, Nikolai Kosjar wrote:
> Recently there were some changes in that area. Could you please try
> again with the updated snapshots for 4.8?
> 
> http://download.qt.io/snapshots/qtcreator/4.8/4.8.0-beta2

I managed to built the latest 4.8 branch on my machine, and still got 
the same issue:

>> I can't reproduce it with a smaller project, but is there any way I can
>> debug this issue? Like get the options that are passed from qmake to the
>> code model?
> 
> A breakpoint in ProjectInfoGenerator::createProjectPart() should help,
> especially on
> 
> 	part->languageVersion = macroInspectionReport.languageVersion;
> 

On the first break after loading the project, 
macroInspectionReport.languageVersion is CXX14 (7). On further breaks, 
it's CXX98 (4).

I cannot find any differences in the respective qmake projects. The 
flags.commandLineFlags that are passed are the following:

-nologo -Zc:wchar_t -FS -Zc:rvalueCast -Zc:inline /wd4503 /w14239 /FC 
/D_LIntStatic /Zi /Fd<path> -O2 -Zi -MD -Zc:strictStrings -W3 -w34100 
-w34189 -w44996 /WX -EHsc

However, I found that in tcInfo.macroInspectionRunner, the "__cplusplus" 
macro has a value of 199711L. This is from msvctoolchain.cpp, which 
shows some information about the possible values:

// We want to detect the language version based on the predefined macros.
// Unfortunately MSVC does not conform to standard when it comes to the 
predefined
// __cplusplus macro - it reports "199711L", even for newer language 
versions.
//
// However:
//   * For >= Visual Studio 2015 Update 3 predefines _MSVC_LANG which 
has the proper value
//     of __cplusplus.
//     See 
https://docs.microsoft.com/en-us/cpp/preprocessor/predefined-macros?view=vs-2017
//   * For >= Visual Studio 2017 Version 15.7 __cplusplus is correct 
once /Zc:__cplusplus
//     is provided on the command line. Then __cplusplus == _MSVC_LANG.
//     See 
https://blogs.msdn.microsoft.com/vcblog/2018/04/09/msvc-now-correctly-reports-__cplusplus
//
// We rely on _MSVC_LANG if possible, otherwise on some hard coded 
language versions
// depending on _MSC_VER.

We're still running MSVC 2013, which doesn't seem to be covered by this 
exceptions. I tested opening the project with a MSVC 2017 Version 15.8 
kit, and with that, the code model reports a C++ version of CXX17 
(although it should be C++11)!

So, I guess this is a bug in Creator regarding C++ version detection 
with MSVC 2013?

If so, I'll file a bug report.

Thanks,
Julius