Building under Windows using MSVC

[mathias-kogler-snkeos]

tl;dr

There are some gcc specific copts in the BUILD files. If I remove them I get errors like error C2491: 'antlr4::dfa::Vocabulary::EMPTY_VOCABULARY': definition of dllimport static data member not allowed and the build fails.
Is building this project under Windows using MSVC supported. Does anyone have any pointers how to make it work?

Full example

If I try to build e.g. the r4 json_format C++ library using bazel build //cc/google/fhir/r4:json_format I get the following errors

PS C:\git\fhir> bazel build //cc/google/fhir/r4:json_format
INFO: Analyzed target //cc/google/fhir/r4:json_format (0 packages loaded, 0 targets configured).
INFO: Found 1 target...
ERROR: C:/users/mathias.kogler/_bazel_mathias.kogler/ee5vwmtg/external/antlr_cc_runtime/BUILD.bazel:3:11: Compiling atn/LL1Analyzer.cpp failed: (Exit 2): cl.exe failed: error executing command C:\Program Files\Microsoft Visual Studio\2022\Professional\VC\Tools\MSVC\14.31.31103\bin\HostX64\x64\cl.exe /nologo /DCOMPILER_MSVC /DNOMINMAX /D_WIN32_WINNT=0x0601 /D_CRT_SECURE_NO_DEPRECATE ... (remaining 40 arguments skipped)
cl : Command line error D8021 : invalid numeric argument '/Wno-implicit-fallthrough'
Target //cc/google/fhir/r4:json_format failed to build
Use --verbose_failures to see the command lines of failed build steps.
INFO: Elapsed time: 0.672s, Critical Path: 0.19s
INFO: 13 processes: 13 internal.
FAILED: Build did NOT complete successfully

If I remove the -Wno-implicit-falltrough from the copts in bazel/antlr.BUILD and change the -cxxopt in .bazelrc from build --cxxopt=-std=c++17 to the msvc format build --cxxopt=/std:c++17 I get the following errors

PS C:\git\fhir> bazel build //cc/google/fhir/r4:json_format
INFO: Build option --cxxopt has changed, discarding analysis cache.
INFO: Analyzed target //cc/google/fhir/r4:json_format (0 packages loaded, 3011 targets configured).
INFO: Found 1 target...
ERROR: C:/users/mathias.kogler/_bazel_mathias.kogler/ee5vwmtg/external/antlr_cc_runtime/BUILD.bazel:3:11: Compiling Vocabulary.cpp failed: (Exit 2): cl.exe failed: error executing command C:\Program Files\Microsoft Visual Studio\2022\Professional\VC\Tools\MSVC\14.31.31103\bin\HostX64\x64\cl.exe /nologo /DCOMPILER_MSVC /DNOMINMAX /D_WIN32_WINNT=0x0601 /D_CRT_SECURE_NO_DEPRECATE ... (remaining 39 arguments skipped)
cl : Command line warning D9002 : ignoring unknown option '-fexceptions'
external/antlr_cc_runtime/Vocabulary.cpp(12): warning C4273: 'EMPTY_VOCABULARY': inconsistent dll linkage
C:\users\mathias.kogler\_bazel_mathias.kogler\ee5vwmtg\execroot\com_google_fhir\external\antlr_cc_runtime\Vocabulary.h(27): note: see previous definition of 'public: static antlr4::dfa::Vocabulary const antlr4::dfa::Vocabulary::EMPTY_VOCABULARY'
external/antlr_cc_runtime/Vocabulary.cpp(12): error C2491: 'antlr4::dfa::Vocabulary::EMPTY_VOCABULARY': definition of dllimport static data member not allowed
external/antlr_cc_runtime/Vocabulary.cpp(14): warning C4273: 'antlr4::dfa::Vocabulary::Vocabulary': inconsistent dll linkage
C:\users\mathias.kogler\_bazel_mathias.kogler\ee5vwmtg\execroot\com_google_fhir\external\antlr_cc_runtime\Vocabulary.h(42): note: see previous definition of '{ctor}'
external/antlr_cc_runtime/Vocabulary.cpp(18): warning C4273: 'antlr4::dfa::Vocabulary::Vocabulary': inconsistent dll linkage
C:\users\mathias.kogler\_bazel_mathias.kogler\ee5vwmtg\execroot\com_google_fhir\external\antlr_cc_runtime\Vocabulary.h(60): note: see previous definition of '{ctor}'
external/antlr_cc_runtime/Vocabulary.cpp(25): warning C4273: 'antlr4::dfa::Vocabulary::~Vocabulary': inconsistent 
dll linkage
C:\users\mathias.kogler\_bazel_mathias.kogler\ee5vwmtg\execroot\com_google_fhir\external\antlr_cc_runtime\Vocabulary.h(18): note: see previous definition of '{dtor}'
external/antlr_cc_runtime/Vocabulary.cpp(28): warning C4273: 'antlr4::dfa::Vocabulary::fromTokenNames': inconsistent dll linkage
C:\users\mathias.kogler\_bazel_mathias.kogler\ee5vwmtg\execroot\com_google_fhir\external\antlr_cc_runtime\Vocabulary.h(76): note: see previous definition of 'fromTokenNames'
external/antlr_cc_runtime/Vocabulary.cpp(61): warning C4273: 'antlr4::dfa::Vocabulary::getMaxTokenType': inconsistent dll linkage
C:\users\mathias.kogler\_bazel_mathias.kogler\ee5vwmtg\execroot\com_google_fhir\external\antlr_cc_runtime\Vocabulary.h(82): note: see previous definition of 'getMaxTokenType'
external/antlr_cc_runtime/Vocabulary.cpp(65): warning C4273: 'antlr4::dfa::Vocabulary::getLiteralName': inconsistent dll linkage
C:\users\mathias.kogler\_bazel_mathias.kogler\ee5vwmtg\execroot\com_google_fhir\external\antlr_cc_runtime\Vocabulary.h(119): note: see previous definition of 'getLiteralName'
external/antlr_cc_runtime/Vocabulary.cpp(73): warning C4273: 'antlr4::dfa::Vocabulary::getSymbolicName': inconsistent dll linkage
C:\users\mathias.kogler\_bazel_mathias.kogler\ee5vwmtg\execroot\com_google_fhir\external\antlr_cc_runtime\Vocabulary.h(163): note: see previous definition of 'getSymbolicName'
external/antlr_cc_runtime/Vocabulary.cpp(85): warning C4273: 'antlr4::dfa::Vocabulary::getDisplayName': inconsistent dll linkage
C:\users\mathias.kogler\_bazel_mathias.kogler\ee5vwmtg\execroot\com_google_fhir\external\antlr_cc_runtime\Vocabulary.h(184): note: see previous definition of 'getDisplayName'
ERROR: C:/users/mathias.kogler/_bazel_mathias.kogler/ee5vwmtg/external/antlr_cc_runtime/BUILD.bazel:3:11: Compiling atn/ATNDeserializationOptions.cpp failed: (Exit 2): cl.exe failed: error executing command C:\Program Files\Microsoft Visual Studio\2022\Professional\VC\Tools\MSVC\14.31.31103\bin\HostX64\x64\cl.exe /nologo /DCOMPILER_MSVC /DNOMINMAX /D_WIN32_WINNT=0x0601 /D_CRT_SECURE_NO_DEPRECATE ... (remaining 39 arguments skipped)
cl : Command line warning D9002 : ignoring unknown option '-fexceptions'
external/antlr_cc_runtime/atn/ATNDeserializationOptions.cpp(10): warning C4273: 'defaultOptions': inconsistent dll linkage
C:\users\mathias.kogler\_bazel_mathias.kogler\ee5vwmtg\execroot\com_google_fhir\external\antlr_cc_runtime\atn/ATNDeserializationOptions.h(15): note: see previous definition of 'private: static antlr4::atn::ATNDeserializationOptions antlr4::atn::ATNDeserializationOptions::defaultOptions'
external/antlr_cc_runtime/atn/ATNDeserializationOptions.cpp(10): error C2491: 'antlr4::atn::ATNDeserializationOptions::defaultOptions': definition of dllimport static data member not allowed
external/antlr_cc_runtime/atn/ATNDeserializationOptions.cpp(12): warning C4273: 'antlr4::atn::ATNDeserializationOptions::ATNDeserializationOptions': inconsistent dll linkage
C:\users\mathias.kogler\_bazel_mathias.kogler\ee5vwmtg\execroot\com_google_fhir\external\antlr_cc_runtime\atn/ATNDeserializationOptions.h(22): note: see previous definition of '{ctor}'
external/antlr_cc_runtime/atn/ATNDeserializationOptions.cpp(16): warning C4273: 'antlr4::atn::ATNDeserializationOptions::ATNDeserializationOptions': inconsistent dll linkage
C:\users\mathias.kogler\_bazel_mathias.kogler\ee5vwmtg\execroot\com_google_fhir\external\antlr_cc_runtime\atn/ATNDeserializationOptions.h(23): note: see previous definition of '{ctor}'
external/antlr_cc_runtime/atn/ATNDeserializationOptions.cpp(21): warning C4273: 'antlr4::atn::ATNDeserializationOptions::~ATNDeserializationOptions': inconsistent dll linkage
C:\users\mathias.kogler\_bazel_mathias.kogler\ee5vwmtg\execroot\com_google_fhir\external\antlr_cc_runtime\atn/ATNDeserializationOptions.h(25): note: see previous definition of '{dtor}'
external/antlr_cc_runtime/atn/ATNDeserializationOptions.cpp(24): warning C4273: 'antlr4::atn::ATNDeserializationOptions::getDefaultOptions': inconsistent dll linkage
C:\users\mathias.kogler\_bazel_mathias.kogler\ee5vwmtg\execroot\com_google_fhir\external\antlr_cc_runtime\atn/ATNDeserializationOptions.h(28): note: see previous definition of 'getDefaultOptions'
external/antlr_cc_runtime/atn/ATNDeserializationOptions.cpp(28): warning C4273: 'antlr4::atn::ATNDeserializationOptions::isReadOnly': inconsistent dll linkage
C:\users\mathias.kogler\_bazel_mathias.kogler\ee5vwmtg\execroot\com_google_fhir\external\antlr_cc_runtime\atn/ATNDeserializationOptions.h(30): note: see previous definition of 'isReadOnly'
external/antlr_cc_runtime/atn/ATNDeserializationOptions.cpp(32): warning C4273: 'antlr4::atn::ATNDeserializationOptions::makeReadOnly': inconsistent dll linkage
C:\users\mathias.kogler\_bazel_mathias.kogler\ee5vwmtg\execroot\com_google_fhir\external\antlr_cc_runtime\atn/ATNDeserializationOptions.h(32): note: see previous definition of 'makeReadOnly'
external/antlr_cc_runtime/atn/ATNDeserializationOptions.cpp(36): warning C4273: 'antlr4::atn::ATNDeserializationOptions::isVerifyATN': inconsistent dll linkage
C:\users\mathias.kogler\_bazel_mathias.kogler\ee5vwmtg\execroot\com_google_fhir\external\antlr_cc_runtime\atn/ATNDeserializationOptions.h(34): note: see previous definition of 'isVerifyATN'
external/antlr_cc_runtime/atn/ATNDeserializationOptions.cpp(40): warning C4273: 'antlr4::atn::ATNDeserializationOptions::setVerifyATN': inconsistent dll linkage
C:\users\mathias.kogler\_bazel_mathias.kogler\ee5vwmtg\execroot\com_google_fhir\external\antlr_cc_runtime\atn/ATNDeserializationOptions.h(36): note: see previous definition of 'setVerifyATN'
external/antlr_cc_runtime/atn/ATNDeserializationOptions.cpp(45): warning C4273: 'antlr4::atn::ATNDeserializationOptions::isGenerateRuleBypassTransitions': inconsistent dll linkage
C:\users\mathias.kogler\_bazel_mathias.kogler\ee5vwmtg\execroot\com_google_fhir\external\antlr_cc_runtime\atn/ATNDeserializationOptions.h(38): note: see previous definition of 'isGenerateRuleBypassTransitions'
external/antlr_cc_runtime/atn/ATNDeserializationOptions.cpp(49): warning C4273: 'antlr4::atn::ATNDeserializationOptions::setGenerateRuleBypassTransitions': inconsistent dll linkage
C:\users\mathias.kogler\_bazel_mathias.kogler\ee5vwmtg\execroot\com_google_fhir\external\antlr_cc_runtime\atn/ATNDeserializationOptions.h(40): note: see previous definition of 'setGenerateRuleBypassTransitions'
external/antlr_cc_runtime/atn/ATNDeserializationOptions.cpp(54): warning C4273: 'antlr4::atn::ATNDeserializationOptions::throwIfReadOnly': inconsistent dll linkage
C:\users\mathias.kogler\_bazel_mathias.kogler\ee5vwmtg\execroot\com_google_fhir\external\antlr_cc_runtime\atn/ATNDeserializationOptions.h(43): note: see previous definition of 'throwIfReadOnly'
external/antlr_cc_runtime/atn/ATNDeserializationOptions.cpp(60): warning C4273: 'antlr4::atn::ATNDeserializationOptions::InitializeInstanceFields': inconsistent dll linkage
C:\users\mathias.kogler\_bazel_mathias.kogler\ee5vwmtg\execroot\com_google_fhir\external\antlr_cc_runtime\atn/ATNDeserializationOptions.h(46): note: see previous definition of 'InitializeInstanceFields'
Target //cc/google/fhir/r4:json_format failed to build
Use --verbose_failures to see the command lines of failed build steps.
INFO: Elapsed time: 3.173s, Critical Path: 2.43s
INFO: 15 processes: 11 internal, 4 local.
FAILED: Build did NOT complete successfully

[mathias-kogler-snkeos]

Would you be open for a pull request which adds support for MSVC?