Building Static Hermes on Windows about hermes

[luboslenco]

can you try building it on Windows with Clang?

Thanks for the tip!

• I installed C++ Clang tools for Windows (16.0.5 - x64/x86) via Visual Studio Installer

• Used the following commands to build:

cmake -S hermes -B build -G 'Visual Studio 17 2022' -T ClangCL -A x64
cmake --build ./build

• This leads to errors / warnings:

clang-cl : warning : unknown argument ignored in clang-cl: '-fvisibility=hidden' [-Wunknown-argument]
clang-cl : warning : unknown argument ignored in clang-cl: '-fno-strict-overflow' [-Wunknown-argument]
clang-cl : warning : unknown argument ignored in clang-cl: '-fno-exceptions' [-Wunknown-argument]
clang-cl : warning : unknown argument ignored in clang-cl: '-fno-rtti' [-Wunknown-argument]
hermes\lib\IR\IR.cpp(574,17): error : 'operator delete' is a private member of 'hermes::Value'
hermes\lib\VM\StaticH.cpp(328,3): error : use of undeclared identifier '_longjmp'; did you mean 'longjmp'?

• The hacky way I got past these (just for testing):

  • Modified CMakeLists.txt to use MSVC sections instead of GCC_COMPATIBLE
  • In lib/VM/StaticH.cpp replaced _longjmp with longjmp
  • In shermes/compile.cpp commented out #include <dlfcn.h> and dlopen() call, removed dl lib from shermes/CMakeLists.txt

• Now the binaries and libs compile successfully

• Set the cc env variable and pointed it to clang.exe

• Used .\shermes.exe -c -typed .\test.ts to produce test.o

• Linked test.o with my project together with hermesvm_a.lib and jsi.lib

• Finally I call the main() function contained in test.o and it works!

[tmikov]

@luboslenco great! Nice job!! It is very good to know that it can build and even run!

We need to figure out how to automatically detect this particular configuration - Clang on Windows with MSVC-compatible CLI, but there shouldn't be any major problems, since Hermes itself compiles and is widely used on Windows.

I don't think we will add it to our CI just yet, but we likely will before the middle of the year.

[luboslenco]

Just a side note, with mostly straightforward build tweaks I was able to run Static Hermes on Android, iOS, Windows (+ macOS and Linux). 🙂

[tmikov]

Hi, this is a very good question. Static Hermes will support Windows but only via Clang, not MSVC. Since Static Hermes will rely on LLVM as a backend, the C output is just temporary, so it is not really worth it to support building the compiler with MSVC, when everything else (including parts of the Static Hermes runtime itself, which are written in JS) relies on LLVM.

This is not set in stone, but is the plan for now.

EDIT: can you try building it on Windows with Clang?