WASM: Runtime Library

[certik]

Original issue: https://gitlab.com/lfortran/lfortran/-/issues/720

Continued from https://gitlab.com/lfortran/lfortran/-/issues/706

Related to https://gitlab.com/lfortran/lfortran/-/issues/700

For the LFortran WebAssembly Backend, we need to get the runtime library working, so that one can use functions like sin/cos, etc.

The runtime library has two parts:

1. pure part (we have to package the .mod files together with the emscripten compiled LFortran. (WASM: Support runtime library #643, Support runtime library lcompilers_frontend#37)
2. impure part (Implemented in C)
   • Add support for print function (https://gitlab.com/lfortran/lfortran/-/merge_requests/1794)
   • Add support for cpu_time (WASM: Add support for cpu_time #641)

[Shaikh-Ubaid]

I tried the following test cases at the current live site https://dev.lfortran.org/

• integration_tests/abs_01.f90
• integration_tests/abs_02.f90
• integration_tests/abs_03.f90
• integration_tests/intrinsics_21.f90 // for modulo() and mod()
• integration_tests/intrinsics_23.f90 // for huge()
• integration_tests/floor_01.f90
• integration_tests/floor_02.f90
• integration_tests/floor_03.f90

They all seem to work. Thus, it seems the runtime library works at https://dev.lfortran.org/

Please, could someone possibly share if this issue is safe to close?

[certik]

Nice, great job!

Try this: use the default example and change dp=8 to dp=kind(0.d0). I get:

Kind of good, but not quite. :)

[Shaikh-Ubaid]

Thank you for sharing the bug, Ondrej Sir. We merged a PR #657 which should (hopefully) fix the issue. I also submitted a PR at lfortran/lcompilers_frontend#40 to update the lfortran version/commit to be used at https://dev.lfortran.org/

[Shaikh-Ubaid]

Try this: use the default example and change dp=8 to dp=kind(0.d0). I get:

With the fixes in #657 and lfortran/lcompilers_frontend#40, the latest lfortran at https://dev.lfortran.org/ seems to now support it.

[Shaikh-Ubaid]

integration_tests/abs_01.f90
integration_tests/abs_02.f90
integration_tests/abs_03.f90
integration_tests/intrinsics_21.f90 // for modulo() and mod()
integration_tests/intrinsics_23.f90 // for huge()
integration_tests/floor_01.f90
integration_tests/floor_02.f90
integration_tests/floor_03.f90

I tested these examples again at https://dev.lfortran.org/. They all seem to work. Thus, it seems the runtime library works at https://dev.lfortran.org/

Please, could someone possibly share if this issue is safe to close?

[certik]

I tested this by hand as well and I think everything is indeed fixed! Amazing.

The parts of the runtime library that do not work are all calls into C, however I am guessing just providing the appropriate JavaScript implementations might fix it. We will eventually use pure Fortran implementations of trigonometric functions like sin(x). But for now we can either implement them in JavaScript, or figure out how to compile the C part of the runtime library using Clang and somehow link it.