TODO for beta #3806

In order to reach beta quality, we need to implement the following items:

• compile at least 10 codes without any workaround (except the items listed in "after beta" below):
  • legacy minpack
  • 60% of SciPy (common blocks and other old features are needed for the rest, we'll tackle after beta)
  • modern minpack
  • fastGPT
  • dftatom
  • stdlib with small workarounds (due to the issues above)
  • lapack Compile Lapack #1232
  • SNAP compiling SNAP #3951 @kmr-srbh, @assem2002
  • prima Compiling PRIMA #4397
  • fpm: Compiling fpm #6840
• Other codes to choose from: Code to be Compiled Projects to be compiled using LFortran compiler
• Progress : Refactor string and string array (LLVM backend) #6892 @assem2002
• Strings TODO #8129
• Linking failure of main program, subroutine, and module combination with implicit-typing and implicit-interface #6512 (global procedures) @Pranavchiku
• robust deallocation (ASR: idea: add explicit nodes to free non-primitive types #3770)
• most OOP features
  • Refactor StructType #4263 (@kmr-srbh )
  • regression: as part of struct-refactor #8115
  • Clean up runtime polymorphism #7068 (@HarshitaKalani )
• Idea: generate ASR.asdl, asr_verify.cpp and doc/src/asr/ from the same source #7006
• Change array descriptor to be inlined #7316
• ASR: Add "deterministic" and "side-effect-free" flags to Function lcompilers/lpython#1266
• Use ClassToStruct cast consistently #9950
• Make any warning configurable #10605
• Add a Debug time check for Vec indexing #7833
• Bounds Checking #8306
• LLVM: get rid of all calls to CreateGEP, replace with CreateGEP2; Replace CreateLoad->CreateLoad2 #7836
• Submodules cleanup : Calling type-bound procedure declared via module and implemented in submodule is causing code generation error #7270
• Refactor all compiler options #7937
• Note about intent(out) arguments, enforce in verify #8005
• Implement opaque pointers for LLVM 17 #4210
• All instrinsic functions working (compile time, runtime): @HarshitaKalani, @parth121101
  • List of Standard generic intrinsic procedure #492
  • GSoC: Intrinsic functions #4017
  • Intrinsics TODO #4593
• Realloc LHS TODO #7069
• --fast working in all cases:
  • Fix and remove all NO_FAST from integration_tests #6505
  • Fix and remove all NOFAST_LLVM16 tags from integration_tests #6504
• Enable LLVM optimizations for --fast with LLVM >= 17 #6480
• Enabling the simplifier pass by default: @czgdp1807
  • Design for array expressions #5201
  • Ensure no expression ballooning happens
  • Ensure no runtime performance degradation for 3rd party codes
• Stacktraces on Ubuntu take a long time #4236
• robust compile time computation (An example for compile time evaluation #3203): @Pranavchiku, @nikabot
• Change the ASR representation of ArrayConstant #3581: @Pranavchiku
• Compiling to WASM via LLVM (few demos, easy to use): @Shaikh-Ubaid
• Test the emscripten-based LLVM backend at the CI (use nodejs to ensure passing data/arrays from JavaScript to Fortran/WASM works) LLVM_WASM: Test emscripten generated wasm in integration_tests #3954
• separate compilation (generate intermediate object files, link everything at the end), add robust first class support for .o files for all backends: LLVM, WASM, WASM/x64, etc., in all cases (all ASR); to allow good interoperability with other toolchains (so that the user can link this into libraries or codes together with other code) Separate compilation TODO #7163 separate compilation Issues or PRs related to separate compilation @Pranavchiku
• Add checks for dangling pointers in Debug mode

After we reach beta, we will tackle the following:

• Performance (LLVM already gives us a very good starting point, but to eventually achieve maximum performance that the hardware allows, we need to implement our own optimization ASR->ASR passes for vectorization, inlining, partitioning, etc. and adjust our LLVM backend and its passes)
• Everything working in interactive mode and Jupyter notebook (@Vipul-Cariappa)
• coarrays
• parallel loops:
  • OpenMP: OpenMP support in AST and ASR #3777: @Pranavchiku
  • GPU offloading to NVIDIA (NVIDIA GPU support #4497), AMD (Offload do concurrent to AMD GPUs #4535) and other GPUs
  • Using NPUs and other custom hardware from many vendors
• submodules
• full generics support (interface based)
• quadruple precision: Quadruple (and higher) precision design #3468
• good support for lists, dicts and other LPython data structures which we'll support as Fortran extensions (@advikkabra)
• good error messages for all invalid code
• Debug time checks (bounds checks, pointer checks, integer overflow, etc.):
  • Check pointers in Debug mode #338
  • Safe mode #341
  • Reference counted pointers #5382
  • Implement Debug time checks for arrays and other features #3279
• Runtime errors improvements #7838
• Fix ptr_loads: ASR idea: explicit pointer vs value #4245
• other features to consider: Potential features #165
• common block and other F77 features that should not be used in new codes (but we have to support to compile old codes)
• Compilation performance:
  • Caching / reusing of ttypes #8172
• Other backends:
  • WASM
  • C/C++
  • NVPTX LLVM backend NVIDIA GPU support #4497
  • SIMD backend #2293
  • Add MLIR backend #4319

Also discussed at https://lfortran.zulipchat.com/#narrow/stream/197339-general/topic/TODO.20for.20Beta.