[swift-users] Compile error trying to follow Swift for Windows MSVC instructions

[Eric Wing]

I'm trying to build Swift for Windows with Visual Studio using the
directions found here:
https://github.com/apple/swift/blob/master/docs/Windows.md

I'm following the MSVC section for directions. I am stuck in step 6.
LLVM/Clang/Compiler-RT

I seem to be hitting a C++ error in the code in IndexDataStore.h. Any
ideas on how to get around this?


C:\PROGRA~2\MICROS~1\2017\COMMUN~1\VC\Tools\MSVC\1411~1.255\bin\Hostx64\x64\cl.exe
 /nologo /TP -DGTEST_HAS_RTTI=0 -DUNICODE -D_CRT_NONSTDC_NO_DEPRECATE
-D_CRT_NONSTDC_NO_WARNINGS -D_CRT_SECURE_NO_DEPRECATE
-D_CRT_SECURE_NO_WARNINGS -D_GNU_SOURCE -D_HAS_EXCEPTIONS=0
-D_SCL_SECURE_NO_DEPRECATE -D_SCL_SECURE_NO_WARNINGS -D_UNICODE
-D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS
-Itools\clang\lib\Index -IC:\Source\SWIFT\llvm\tools\clang\lib\Index
-IC:\Source\SWIFT\llvm\tools\clang\include -Itools\clang\include
-Iinclude -IC:\Source\SWIFT\llvm\include /DWIN32 /D_WINDOWS
/Zc:inline /Zc:strictStrings /Oi /Zc:rvalueCast /W4 -wd4141 -wd4146
-wd4180 -wd4244 -wd4258 -wd4267 -wd4291 -wd4345 -wd4351 -wd4355
-wd4456 -wd4457 -wd4458 -wd4459 -wd4503 -wd4624 -wd4722 -wd4800
-wd4100 -wd4127 -wd4512 -wd4505 -wd4610 -wd4510 -wd4702 -wd4245
-wd4706 -wd4310 -wd4701 -wd4703 -wd4389 -wd4611 -wd4805 -wd4204
-wd4577 -wd4091 -wd4592 -wd4319 -wd4324 -w14062 -we4238 /MD /O1 /Ob1
-UNDEBUG  /EHs-c- /GR- /showIncludes
/Fotools\clang\lib\Index\CMakeFiles\clangIndex.dir\IndexDataStore.cpp.obj
/Fdtools\clang\lib\Index\CMakeFiles\clangIndex.dir\clangIndex.pdb /FS
-c C:\Source\SWIFT\llvm\tools\clang\lib\Index\IndexDataStore.cpp
C:\Source\SWIFT\llvm\tools\clang\include\clang/Index/IndexDataStore.h(41):
error C3646: 'ModTime': unknown override specifier
C:\Source\SWIFT\llvm\tools\clang\include\clang/Index/IndexDataStore.h(41):
error C4430: missing type specifier - int assumed. Note: C++ does not
support default-int
C:\Source\SWIFT\llvm\tools\clang\include\clang/Index/IndexDataStore.h(74):
error C3646: 'ModTime': unknown override specifier
C:\Source\SWIFT\llvm\tools\clang\include\clang/Index/IndexDataStore.h(74):
error C4430: missing type specifier - int assumed. Note: C++ does not
support default-int
C:\Source\SWIFT\llvm\tools\clang\lib\Index\IndexDataStore.cpp(164):
error C2039: 'ModTime': is not a member of
'clang::index::AbstractDirectoryWatcher::Event'
C:\Source\SWIFT\llvm\tools\clang\include\clang/Index/IndexDataStore.h(38):
note: see declaration of
'clang::index::AbstractDirectoryWatcher::Event'
C:\Source\SWIFT\llvm\tools\clang\lib\Index\IndexDataStore.cpp(164):
error C2039: '__this': is not a member of
'clang::index::AbstractDirectoryWatcher::Event'
C:\Source\SWIFT\llvm\tools\clang\include\clang/Index/IndexDataStore.h(38):
note: see declaration of
'clang::index::AbstractDirectoryWatcher::Event'
[2723/3603] Building CXX object
tools\clang\lib\Index\CMakeFiles\clangIndex.dir\IndexingContext.cpp.obj
ninja: build stopped: subcommand failed.


Note: I'm using VS2017 instead of VS2015 because it's supposed to have
better C++ conformance.

I also want to note, building Debug hits a different fatal error where
MSVC aborts saying you must compile with /bigobj because the files are
too large. I changed my build and then hit the above compile error
with IndexDataStore.h. I then tried building a release version without
/bigobj, but I hit the same compile error with IndexDataStore.h.





Also, can somebody clarify what the differences are between the
different build approaches in the document (clang vs. MSVC vs.
clang-cl). Will these all produce binaries that are interoperable with
each other and allow me to link against regular MSVC built C
libraries? And do one of these clang options need MSVC's clang-C2?

And also, what is Compiler-RT and since it is optional, what do I lose
if I skip it?

And finally, why is the Win10 SDK needed? Doesn't that mean it won't
work on Win7 or Win8? What could Swift need that requires Win10 APIs?

Thanks,
Eric