Hoist CFGState and BBState out of function scope

[gmittert]

MSVC (Version 19.15.26726) has some really wonky behaviour with enums and
structs in function scopes. Hoisting them outside seems to work around
it.

Here's the error message, I don't at all understand why it would cause this specific error.

C:\PROGRA~2\MIB055~1\2017\PROFES~1\VC\Tools\MSVC\1415~1.267\bin\Hostx64\x64\cl.exe  /nologo /TP -DCMARK_STATIC_DEFINE -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_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 -Ilib\SIL -Iswift\lib\SIL -Iinclude -Iswift\include -Illvm\include -Ibuild\Ninja-DebugAssert\llvm-windows-amd64\include -Ibuild\Ninja-DebugAssert\llvm-windows-amd64\tools\clang\include -Illvm\tools\clang\include -Icmark\src -Ibuild\Ninja-DebugAssert\cmark-windows-amd64\src -I"C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\VC\Tools\MSVC\14.15.26726\\include" -I"C:\Program Files (x86)\Windows Kits\10\\Include\10.0.17134.0\ucrt" -I"C:\Program Files (x86)\Windows Kits\10\\Include\10.0.17134.0\shared" -I"C:\Program Files (x86)\Windows Kits\10\\Include\10.0.17134.0\um" /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 /we4062 /wd4068 -DOBJC_OLD_DISPATCH_PROTOTYPES=0 /MDd /Zi /Ob0 /Od /RTC1    /EHs-c- /GR- /Od -DLLVM_ON_WIN32 -D_CRT_SECURE_NO_WARNINGS -D_CRT_NONSTDC_NO_WARNINGS -D_CRT_USE_WINAPI_FAMILY_DESKTOP_APP -D_DLL -D_ENABLE_ATOMIC_ALIGNMENT_FIX -D_HAS_STATIC_RTTI=0 -UNDEBUG -std:c++14 /Folib\SIL\CMakeFiles\swiftSIL.dir\SILVerifier.cpp.obj /Fdlib\SIL\CMakeFiles\swiftSIL.dir\swiftSIL.pdb /FS -c swift\lib\SIL\SILVerifier.cpp
swift\lib\SIL\SILVerifier.cpp(4831): error C2888: 'void swift::SILFunction::verify(bool) const': symbol cannot be defined within namespace 'std'
swift\lib\SIL\SILVerifier.cpp(4842): error C2888: 'void swift::SILFunction::verifyCriticalEdges(void) const': symbol cannot be defined within namespace 'std'
swift\lib\SIL\SILVerifier.cpp(4851): error C2888: 'void swift::SILProperty::verify(const swift::SILModule &) const': symbol cannot be defined within namespace 'std'
swift\lib\SIL\SILVerifier.cpp(4906): error C2888: 'void swift::SILVTable::verify(const swift::SILModule &) const': symbol cannot be defined within namespace 'std'
swift\lib\SIL\SILVerifier.cpp(4963): error C2888: 'void swift::SILWitnessTable::verify(const swift::SILModule &) const': symbol cannot be defined within namespace 'std'
swift\lib\SIL\SILVerifier.cpp(5003): error C2888: 'void swift::SILDefaultWitnessTable::verify(const swift::SILModule &) const': symbol cannot be defined within namespace 'std'
swift\lib\SIL\SILVerifier.cpp(5033): error C2888: 'void swift::SILGlobalVariable::verify(void) const': symbol cannot be defined within namespace 'std'
swift\lib\SIL\SILVerifier.cpp(5058): error C2888: 'void swift::SILModule::verify(void) const': symbol cannot be defined within namespace 'std'
swift\lib\SIL\SILVerifier.cpp(5149): error C2888: 'bool swift::maybeScopeless(swift::SILInstruction &)': symbol cannot be defined within namespace 'std'

Very oddly, commenting out all the insertResult.first->second lines (Lines 4536, 4543, 4565) also makes the error message go away.

I also see the error in #19303, but since hoisting out BBState is what fixed it, I also had to hoist out CFGState as in that PR.

Also, with this change, Swift successfully now compiles and links (but immediately crashes when run) on Windows building with MSVC on my machine.

[gottesmm]

This looks simple enough. I am slightly worried about infecting the struct level namespace here with these constructs. Maybe instead construct a subtype in there that verifies the flow sensitive rules instead?

[gmittert]

I've now nested the enum in the struct, that way Normal/YieldOnceResumed/YieldUnwind don't get dumped into the namespace.

[compnerd]

@swift-ci please test

[compnerd]

@swift-ci please test

[lanza]

@swift-ci please test

[swift-ci]

Build failed
Swift Test Linux Platform
Git Sha - c71d24b

[lanza]

@swift-ci please test Linux Platform

[lanza]

@compnerd Is this approved?

[gottesmm]

LGTM