I'm in the process of installing them. https://docs.microsoft.com/en-us/cpp/build/reference/qspectre?view=msvc-160#performance-impact says:
"The performance impact of /Qspectre appeared to be negligible in several sizable code bases." so hopefully that applies to us as well.
On 11/13/20 11:06 AM, Maynard, Chris via Wireshark-dev wrote:
> I noticed in the CMakeError.log file the following:
>
> C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Microsoft\VC\v160\Microsoft.CppBuild.targets(458,5): error MSB8040: Spectre-mitigated libraries are required for this project. Install them from the Visual Studio installer (Individual components tab) for any toolsets and architectures being used. Learn more: _https://aka.ms/Ofhn4c_ <https://aka.ms/Ofhn4c>
>
> I installed the Spectre-mitigated libraries and this error message no longer appears. CMake also now reports:
>
> Performing C SOURCE FILE Test C_Qspectre_VALID succeeded
> Performing C++ SOURCE FILE Test CXX_Qspectre_VALID succeeded
>
> However, it seems the Windows buildbots[1][2][3] do not have these Spectre-mitigated libraries installed, because in the most recent CMake stdio output from the two Windows master builders, Windows Server 2019 x64 and Windows Server 2019 x86, I see:
>
> -- Performing Test C_Qspectre_VALID
> -- Performing Test C_Qspectre_VALID - Failed
> -- Performing Test CXX_Qspectre_VALID
> -- Performing Test CXX_Qspectre_VALID - Failed
>
> Should the Spectre-mitigated libraries be installed on all Windows buildbots, and should the Wireshark Developer’s Guide[4] be updated to inform developers to also install them?
> - Chris
> [1]: _https://buildbot.wireshark.org/wireshark-master/waterfall_ <https://buildbot.wireshark.org/wireshark-master/waterfall>
> [2]: _https://buildbot.wireshark.org/wireshark-3.4/waterfall_ <https://buildbot.wireshark.org/wireshark-3.4/waterfall>
> [3]: _https://buildbot.wireshark.org/wireshark-3.2/waterfall_ <https://buildbot.wireshark.org/wireshark-3.2/waterfall>
> [3]: _https://www.wireshark.org/docs/wsdg_html_chunked/ChSetupWin32.html#ChSetupMSVC_ <https://www.wireshark.org/docs/wsdg_html_chunked/ChSetupWin32.html#ChSetupMSVC>
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