MSVC 2017 /Fp and /Yc and /Yu Flags Broken On 391bf6b7609e14f5976bd5247b68d63cbf8d4d12

[gblikas]

Running the default example /CMakeLists.txt (top-most CMake Project), via the following command has some interesting command-line settings, which do not seem to actually utilize a pch system. I am running MSVC 2017 (x64).

mkdir build 
cd build
cmake -G "Visual Studio 15 2017 Win64" ../

In particular, here is [example Property Page] -> [C/C++] -> [Command Line] output:

/GS /TP /W3 /Zc:wchar_t /Zi /Gm- /Od /Ob0 /Fd"example.dir\Debug\vc141.pdb" /Zc:inline /fp:precise /D "WIN32" /D "_WINDOWS" /D "CMAKE_INTDIR=\"Debug\"" /D "_MBCS" /errorReport:prompt /WX- /Zc:forScope /RTC1 /GR /Gd /MDd /FC /Fa"Debug/" /EHsc /nologo /Fo"example.dir\Debug\" /Fp"example.dir\Debug\example.pch" /diagnostics:classic 

For one, /Yu is not used, which causes the core MSVC system not to use a pre-compiled header (afaik, I am not a MSVC wiz). However, it is set in the following 2 methods:

cotire/CMake/cotire.cmake

Line 1627 in 391bf6b

function (cotire_add_pch_compilation_flags _language _compilerID _compilerVersion _prefixFile _pchFile _hostFile _flagsVar)

and

cotire/CMake/cotire.cmake

Line 1786 in 391bf6b

function (cotire_add_prefix_pch_inclusion_flags _language _compilerID _compilerVersion _prefixFile _pchFile _flagsVar)

Another interesting quirk is that /Fp"example.dir\Debug\example.pch doesn't exist:

It seems like in either the _unity build, or standard target name build, both should point to the pch content in /build/src/Debug/cotire:

---

If this is already explained in the documentation, I would love to figure out where. I am new to Cotire, so sorry for any obvious mistakes I may have made. Additionally, here is my vswhere.exe output, and CMake version information.

• cmake version 3.12.1 
  
  CMake suite maintained and supported by Kitware (kitware.com/cmake)
  

•   "instanceId": "2dae49ae",
    "installDate": "2018-07-12T20:38:51Z",
    "installationName": "VisualStudio/15.9.4+28307.222",
    "installationPath": "C:\\Program Files (x86)\\Microsoft Visual Studio\\2017\\Community",
    "installationVersion": "15.9.28307.222",
    "productId": "Microsoft.VisualStudio.Product.Community",
    "productPath": "C:\\Program Files (x86)\\Microsoft Visual Studio\\2017\\Community\\Common7\\IDE\\devenv.exe",
    "isPrerelease": false,
    "displayName": "Visual Studio Community 2017",
    "description": "Free, fully-featured IDE for students, open-source and individual developers",
    "channelId": "VisualStudio.15.Release",
    "channelUri": "https://aka.ms/vs/15/release/channel",
    "enginePath": "C:\\program files (x86)\\microsoft visual studio\\installer\\resources\\app\\ServiceHub\\Services\\Microsoft.VisualStudio.Setup.Service",
    "releaseNotes": "https://go.microsoft.com/fwlink/?LinkId=660692#15.9.4",
    "thirdPartyNotices": "https://go.microsoft.com/fwlink/?LinkId=660708",
    "updateDate": "2018-12-28T22:26:39.937551Z",
    "catalog": {
      "buildBranch": "d15.9",
      "buildVersion": "15.9.28307.222",
      "id": "VisualStudio/15.9.4+28307.222",
      "localBuild": "build-lab",
      "manifestName": "VisualStudio",
      "manifestType": "installer",
      "productDisplayVersion": "15.9.4",
      "productLine": "Dev15",
      "productLineVersion": "2017",
      "productMilestone": "RTW",
      "productMilestoneIsPreRelease": "False",
      "productName": "Visual Studio",
      "productPatchVersion": "4",
      "productPreReleaseMilestoneSuffix": "1.0",
      "productRelease": "RTW",
      "productSemanticVersion": "15.9.4+28307.222",
      "requiredEngineVersion": "1.18.1042.9589"
    },
    "properties": {
      "campaignId": "369401847.1529645426",
      "channelManifestId": "VisualStudio.15.Release/15.9.4+28307.222",
      "nickname": "2",
      "setupEngineFilePath": "C:\\Program Files (x86)\\Microsoft Visual Studio\\Installer\\vs_installershell.exe"
    }```
  
  

[gblikas]

@sakra Have you gotten a chance to look at this?

[enricodetoma]

I understand that it might not be a solution for you if you need/want to use Visual Studio IDE, but I'm using VSCode + Visual C++ 2017 + Cotire + Ninja build and /Yu and /Fp flags are all correctly set.

I decided to abandon Visual Studio IDE because it's intellisense was too slow, and I'm quite happy with the current setup, now.

[gblikas]

@enricodetoma Have you had a similar experience using a similar setup like I have?

[enricodetoma]

Sorry no. I wasn't using cotire yet, when I used cmake + visual studio ide.