Convert System.Globalization unix calls to QCalls into coreclr

[safern]

Relates to: #826
Since we now need to include the headers as part of mscorlib in order to define the QCall entry points, I had to use uint16_t instead of UChar. Per ICU's documentation UChar is an unsigned int of 16bits -- since we don't want to include headers from external libraries into coreclr build.

Note: marked as no-merge as since this is touching perf sensitive code paths, to measure perf.

cc: @ericstj

[jkotas]

I think it would be better to compile this separately from vm, without including PAL headers, to avoid collisions with PAL headers. Dealing with the PAL and system headers collisions is a losing battle.

[safern]

I think it would be better to compile this separately from vm, without including PAL headers, to avoid collisions with PAL headers. Dealing with the PAL and system headers collisions is a losing battle.

Do you mean defining new headers for the functions that are going to be qcalls directly in the vm? Or could you provide an example?

[safern]

Do you mean defining new headers for the functions that are going to be qcalls directly in the vm? Or could you provide an example?

I see, so you actually mean compiling in another partition of the runtime, which one would you suggest?

[jkotas]

you actually mean compiling in another partition of the runtime, which one would you suggest?

Yep. It can be the src\coreclr\src\libraries-native that you have added in last PR.

I think you should be able to keep the shim implementation intact, and just add src\coreclr\src\libraries-native\entrypoints.c file that looks like this:

#include "pal_calendarData.h"
#include "pal_casing.h"
...

#define FCFuncStart(name) extern const void* name[]; const void* name[] = {
#define FCFuncEnd() 0x01 /* FCFuncFlag_EndOfArray */ };

#define QCFuncElement(name,impl) \
    (BYTE*)0x8 /* FCFuncFlag_QCall */, (LPVOID)(impl), (LPVOID)name,

FCFuncStart(gPalGlobalizationNative)
    QCFuncElement("ChangeCase", GlobalizationNative_ChangeCase)
    QCFuncElement("ChangeCaseInvariant", GlobalizationNative_ChangeCaseInvariant)
...
FCFuncEnd()

And then have a registration in ecalllist.h like:

extern "C" const void* gPalGlobalizationNative[];
...
FCClassElement("Globalization", "", gPalGlobalizationNative)
...

[safern]

Thanks, I will try that!

[safern]

Thanks for the reviews 😄 -- I've addressed all feedback.

[jkotas]

The test failures seems to be related to this change. Do not merge before fixing them.

[safern]

Yes I saw that, will investigate later. It seems to be related to getting the version. Thanks for all your reviews @jkotas!