Implement real and imag for complex

[Smit-create]

Part of #232
Fixes #229

[Smit-create]

Presently, the following check fails on this line:

def test():
    x: c64
    x = 2 + 3j
    a: f64
    a = x.imag

ASR:

file "/Users/thebigbool/repos/lpython/src/lpython/semantics/python_ast_to_asr.cpp", line 1801
    LFORTRAN_ASSERT(var->m_value);
AssertFailed: var->m_value

This might be because we are keeping value as nullptr while creating a variable which I expect to be changed after the assignment. @certik What are your views/suggestions on this?

[certik]

The m_value member is only present if there is a compile time value. Otherwise it is nullptr. What you implemented below is a compile time "optimization", which is always good to have, but the main thing to implement is a runtime evaluation, so you have to create a node. For real, just cast the complex to real. For imag, you'll have to call a function. You can see LFortran for %re and %im, which is the same thing.

[Smit-create]

Yep, real seems to be working fine, but still finding some issues with imag.

[Smit-create]

diff --git a/src/runtime/lpython_builtin.py b/src/runtime/lpython_builtin.py
index e439f9d2c..0e338f501 100644
--- a/src/runtime/lpython_builtin.py
+++ b/src/runtime/lpython_builtin.py
@@ -289,10 +289,13 @@ def lbound(x: i32[:], dim: i32) -> i32:
 def ubound(x: i32[:], dim: i32) -> i32:
     pass
 
+@ccall
+def _lfortran_zaimag(x: c64) -> f64:
+    pass
 
 @overload
 def imag(x: c64) -> f64:
-    pass
+    return _lfortran_zaimag(x)

This fails and produces this error:

code generation error: Intrinsic '_lfortran_zaimag' not implemented yet and compile time value is not available.


Note: if any of the above error or warning messages are not clear or are lacking
context please report it to us (we consider that a bug that needs to be fixed).

[Smit-create]

Is this something related to #239 ?

[certik]

Add --show-stacktrace to see where it is coming from. Not sure right now.

[Smit-create]

I have the following stack trace:

Traceback

Traceback (most recent call last):
  File "/Users/thebigbool/repos/lpython/src/bin/lpython.cpp", line 745
    err = compile_python_to_object_file(arg_file, tmp_o, runtime_library_dir, compiler_options);
  File "/Users/thebigbool/repos/lpython/src/bin/lpython.cpp", line 262
    res = fe.get_llvm3(*asr, diagnostics);
  File "/Users/thebigbool/repos/lpython/src/lpython/fortran_evaluator.cpp", line 58
    if (res.ok) {
  File "/Users/thebigbool/repos/lpython/src/libasr/codegen/asr_to_llvm.cpp", line 4170
    v.visit_asr((ASR::asr_t&)asr);
  File "../libasr/asr.h", line 2396
  File "../libasr/asr.h", line 2374
  File "../libasr/asr.h", line 2397
  File "../libasr/asr.h", line 2232
  File "/Users/thebigbool/repos/lpython/src/libasr/codegen/asr_to_llvm.cpp", line 904
    visit_symbol(*mod);
  File "../libasr/asr.h", line 2399
  File "../libasr/asr.h", line 2241
  File "/Users/thebigbool/repos/lpython/src/libasr/codegen/asr_to_llvm.cpp", line 1237
    visit_procedures(x);
  File "/Users/thebigbool/repos/lpython/src/libasr/codegen/asr_to_llvm.cpp", line 2415
    visit_Function(*s);
  File "/Users/thebigbool/repos/lpython/src/libasr/codegen/asr_to_llvm.cpp", line 1968
    generate_function(x);
  File "/Users/thebigbool/repos/lpython/src/libasr/codegen/asr_to_llvm.cpp", line 2320
    this->visit_stmt(*x.m_body[i]);
  File "../libasr/asr.h", line 2411
  File "../libasr/asr.h", line 2260
  File "/Users/thebigbool/repos/lpython/src/libasr/codegen/asr_to_llvm.cpp", line 2480
    this->visit_expr_wrapper(x.m_value, true);
  File "/Users/thebigbool/repos/lpython/src/libasr/codegen/asr_to_llvm.cpp", line 2505
    this->visit_expr(*x);
  File "../libasr/asr.h", line 2444
  File "../libasr/asr.h", line 2305
  File "/Users/thebigbool/repos/lpython/src/libasr/codegen/asr_to_llvm.cpp", line 4047
    throw CodeGenError("Intrinsic '" + func_name + "' not implemented yet and compile time value is not available.");
  File "/Users/thebigbool/repos/lpython/src/libasr/codegen/asr_to_llvm.cpp", line 93
    { }
  File "/Users/thebigbool/repos/lpython/src/libasr/codegen/asr_to_llvm.cpp", line 92
    : d{diag::Diagnostic(msg, diag::Level::Error, diag::Stage::CodeGen)}
code generation error: Intrinsic '_lfortran_zaimag' not implemented yet and compile time value is not available.

I believe it is because we don't have an implementation in pure python for this at present and ccall is not supported for this?

[gptsarthak]

Hey @Smit-create , I was working with intrinsic functions and got the same error.
All I did was call set_intrinsic() for all intrinsic functions starting whose name starts with _lfortran_.

I believe it is because we don't have an implementation in pure python for this at present and ccall is not supported for this?

This is true for all intrinsic functions in lfortran_intrinsics.c. How did you solve this issue?
Doubt cleared 👍

[Smit-create]

I think the CI fails because of recent changes in libasr. Before rebasing, the tests we working fine locally.

[certik]

Now the CI works. Is there anything in libasr that broke main? If so, please let me know.

[Smit-create]

Now it works fine. Thanks.

[certik]

I think this is good to go in. There are still some bugs, but we can fix them in subsequent PRs.

[namannimmo10]

Looks like we need to rebase with the main branch.