Sync LibASR with LFortran

[ubaidsk]

PR at LFortran lfortran/lfortran#6780.

[certik]

Locally I got:

[ 98%] Linking CXX executable test_stacktrace
[ 99%] Linking CXX executable test_lpython
[ 99%] Built target test_stacktrace
[ 99%] Built target test_lpython
[100%] Linking CXX executable lpython
/bin/sh: ../../lfortran/libasr/dwarf_convert.py: No such file or directory
make[2]: *** [src/bin/CMakeFiles/lpython.dir/build.make:153: src/bin/lpython] Error 127
make[2]: *** Deleting file 'src/bin/lpython'
make[1]: *** [CMakeFiles/Makefile2:457: src/bin/CMakeFiles/lpython.dir/all] Error 2
make: *** [Makefile:166: all] Error 2

[ubaidsk]

Locally I got:

I didn't see those locally. What build steps did you use?

[certik]

I just used the usual ./build0.sh && ./build1.sh. I use macOS, so it it calling that Python script which had incorrect path. I fixed it.

[certik]

Main has 363 integration tests. This PR has 204. So we have 159 tests that we need to fix. The classes of tests that we disabled are:

• Some array tests
• Almost all bind(c) tests (C interop), and all symbolics
• A lot of string, list, dict, elemental and math functions,
• A lot of structs
• lpython decorator

So essential functionality, but it hopefully shouldn't be hard to get it working again, since the code in libasr is available at https://github.com/lcompilers/lpython/tree/635ed2020123199c22f25d3dd23056cd80717762/src/libasr and we just need to port the implementation from it to the newest LPython by:

• port a given change to libasr/* (create a branch in the submodule there)
• port any changes in the frontend needed
• enable some test, ensure it works locally
• commit the new submodule hash (that contains your branch)
• push the libasr branch into your fork of lfortran at github
• send a PR against LPython, which will contain the new hash for libasr, and it will be accessible because you pushed into your fork in the previous step; ensure CI passes
• create a PR in LFortran using your pushed branch in the fork; ensure CI passes, and add any LFortran tests that are needed so that the change is fully tested in LFortran, which acts as the upstream for libasr, so that the new change doesn't get broken as LFortran is developed.
• Merge the LFortran PR, ensure the LPython PR is pointing to a hash from the main branch of LFortran (either by updating the hash to the latest main, or by ensuring the LFortran PR merged the commit that the LPython PR depended on)
• Merge the LPython PR

Before doing some big refactoring or feature in libasr, it's a good idea to first update the submodule to the latest main of LFortran and ensure everything passes. It's a good idea to regularly do this update, to keep in sync.

Some other things to fix:

• in src/CMakeLists.txt remove add_subdirectory(${CMAKE_SOURCE_DIR}/libasr/src/libasr ${CMAKE_BINARY_DIR}/libasr) and rather source it from the root CMake. Also do not use ${CMAKE_BINARY_DIR}/ for add_subdirectory.