Implementing Symbolic ASR pass

[anutosh491]

The pass should be responsible for converting the ASR of Program 1 to Prorgam 2
Program 1

from lpython import S
from sympy import pi

def main0():
    x: S = pi
    print(x)

if __name__ == "__main__":
   main0()

Program 2

from lpython import ccall, CPtr, p_c_pointer, pointer, i64, empty_c_void_p
import os

@ccall(header="symengine/cwrapper.h", c_shared_lib="symengine", c_shared_lib_path=f"{os.environ['CONDA_PREFIX']}/lib")
def basic_new_stack(x: CPtr) -> None:
    pass

@ccall(header="symengine/cwrapper.h", c_shared_lib="symengine", c_shared_lib_path=f"{os.environ['CONDA_PREFIX']}/lib")
def basic_const_pi(x: CPtr) -> None:
    pass

@ccall(header="symengine/cwrapper.h", c_shared_lib="symengine", c_shared_lib_path=f"{os.environ['CONDA_PREFIX']}/lib")
def basic_str(x: CPtr) -> str:
    pass

def main0():
    y: i64 = i64(0)
    x: CPtr = empty_c_void_p()
    p_c_pointer(pointer(y, i64), x)
    basic_new_stack(x)
    basic_const_pi(x)
    print(basic_str(x))

if __name__ == "__main__":
   main0()

[anutosh491]

Most of this PR was reviewed in #2200 but there was it seems there are some issues on the branch , hence I've created a duplicate branch of the same .

[Thirumalai-Shaktivel]

Awesome, Looks great!

Test the following and see if it works as expected.

from lpython import S
from sympy import pi

def main0():
    x: S = pi
    y: S = pi
    print(x)

if __name__ == "__main__":
   main0()

[anutosh491]

Hello @Thirumalai-Shaktivel , I have implemented the visit_Print function in the latest commit to transform the Print node from block 1 to block 2

# block 1
                                    (Print
                                        ()
                                        [(Var 3 x)]
                                        ()
                                        ()
                                    )
                                    
 # block 2
 (Print
                                        ()
                                        [(FunctionCall
                                            2 basic_str
                                            2 basic_str
                                            [((Var 3 x))]
                                            (Character 1 -2 ())
                                            ()
                                            ()
                                        )]
                                        ()
                                        ()
                                    )

I now get the required result for the program you've mentioned above through the llvm and the c backend

(lf) anutosh491@spbhat68:~/lpython/lpython$ lpython --enable-symengine examples/expr2.py 
pi
(lf) anutosh491@spbhat68:~/lpython/lpython$ lpython --enable-symengine --backend=c examples/expr2.py 
pi

[Thirumalai-Shaktivel]

Beautiful! Great progress!

[anutosh491]

The symbol_set function would look something like

@ccall(header="symengine/cwrapper.h")
def symbol_set(x: CPtr, s: str) -> None:
    pass

Hence I think I have the correct implementation in place for it . But for the following program , I am not able to get the pass working unlike the pi assignment case .

(lf) anutosh491@spbhat68:~/lpython/lpython$ cat examples/expr2.py 
from lpython import S
from sympy import pi, Symbol

def main0():
    x: S = Symbol("x")
    print(x)

if __name__ == "__main__":
   main0()
(lf) anutosh491@spbhat68:~/lpython/lpython$ lpython --show-asr --pass=symbolic examples/expr2.py
ASR verify pass error: ASR verify: Function symbol_set doesn't depend on basic_new_stack but is found in its dependency list.
Internal Compiler Error: Unhandled exception
Traceback (most recent call last):
  Binary file "/home/anutosh491/lpython/lpython/src/bin/lpython", in _start()
  Binary file "/lib/x86_64-linux-gnu/libc.so.6", in __libc_start_main()
  File "/home/anutosh491/lpython/lpython/src/bin/lpython.cpp", line 1797, in ??
    return emit_asr(arg_file, lpython_pass_manager, runtime_library_dir,
  File "/home/anutosh491/lpython/lpython/src/bin/lpython.cpp", line 252, in ??
    pass_manager.apply_passes(al, asr, pass_options, diagnostics);
  File "/home/anutosh491/lpython/lpython/src/libasr/pass/pass_manager.h", line 280, in LCompilers::PassManager::apply_passes(Allocator&, LCompilers::ASR::TranslationUnit_t*, LCompilers::PassOptions&, LCompilers::diag::Diagnostics&)
    apply_passes(al, asr, _user_defined_passes, pass_options,
LCompilersException: Verify failed in the pass: symbolic

It says Function symbol_set doesn't depend on basic_new_stack but is found in its dependency list. but I don't see it being added to the dependency list manually by me !

[anutosh491]

I've now added functionality for all unary and binary functions that have been implemented through these Prs
#1964 , #2077 & #2094 .
Hence from the pass now we can achieve something like this both through the C and the LLVM backend.

(lf) anutosh491@spbhat68:~/lpython/lpython$ cat examples/expr2.py 
from lpython import S
from sympy import Symbol, sin, diff

def main0():
    x: S = Symbol('x')
    y: S = sin(x)
    z: S = diff(y, x)
    print(y)
    print(z)

if __name__ == "__main__":
   main0()
(lf) anutosh491@spbhat68:~/lpython/lpython$ lpython --enable-symengine examples/expr2.py
sin(x)
cos(x)
(lf) anutosh491@spbhat68:~/lpython/lpython$ lpython --enable-symengine --backend=c examples/expr2.py
sin(x)
cos(x)

[anutosh491]

I've added the symbolic integer through casting in my latest commit to achieve the following functionality

(lf) anutosh491@spbhat68:~/lpython/lpython$ cat examples/expr2.py 
from lpython import S
from sympy import pi

def main0():
    x: S = S(20)
    y: S = S(40)
    z: S = x * y
    print(z)

if __name__ == "__main__":
   main0()

(lf) anutosh491@spbhat68:~/lpython/lpython$ lpython --enable-symengine examples/expr2.py
800

I think we could stop at this point , review this and implement other things in the subsequent PRs. @Thirumalai-Shaktivel

[Thirumalai-Shaktivel]

LGTM!

[certik]

I think that this is fine.

How long will it take to re-enable at least half of the other tests?

[anutosh491]

I think it should all be done within a weeks time !
Only two things need to be supported

1. Generating temporary variables using the symengine queue and using that whenever required (chaining of operators etc)
2. Supporting assert statements

Actually 2 won't be challenging once 1 is done .
For eg we can do everything in this program (symbolics_01.py) except the last line (assert statement) . Now that is because the right hand side is pi + y for which we would need 1 . pi + y would be stored in queue0 , which would be a variable/symbol introduced in the symbol table and assert would just compare z and queue0.

from sympy import Symbol, pi
from lpython import S

def main0():
    x: S = Symbol('x')
    y: S = Symbol('y')
    x = pi
    z: S = x + y
    print(z)
    assert(z == pi + y)

[certik]

This PR will not conflict, since it just adds a pass. So let's keep it open. Let's not add any more commits to this PR.

To implement 1. above, just open a new PR, that builds upon this one. Implement 1. We'll see how many tests will start working.

What I don't want to happen is the current capability to break while we are building this. Only once most of the tests pass, I am happy to do the switch.

[anutosh491]

Yes I think we should proceed like above . Thanks for the review .

Fixed

[certik]

Merged as part of #2255.