FIX: segfault in string handling

[Pranavchiku]

Fixes: #2997.

TODO:

• Get all integration tests pass

[Pranavchiku]

SciPy failure MRE:

SUBROUTINE PRINI()
CHARACTER *1 MES(1)
RETURN
ENTRY PRIN(MES)
RETURN
END

% lfortran a.f90 
style suggestion: Use character(1) instead of character*1
 --> a.f90:3:1
  |
3 | CHARACTER *1 MES(1)
  | ^^^^^^^^^^^^ help: write this as 'character(1)'

ASR verify pass error: ASR verify: Array type in pointer must have deferred shape
 --> a.f90:3:1
  |
3 | CHARACTER *1 MES(1)
  | ^^^^^^^^^^^^^^^^^^^ failed here


Note: Please report unclear or confusing messages as bugs at
https://github.com/lfortran/lfortran/issues.

[Pranavchiku]

I have made progress over this, I get code generation error now:

% lfortran a.f90 --show-llvm --no-warnings
; ModuleID = 'LFortran'
source_filename = "LFortran"

%array = type { i8**, i32, %dimension_descriptor*, i1, i32 }
%dimension_descriptor = type { i32, i32, i32 }

define void @prin([1 x i8*] %mes) {
.entry:
  %call_arg_value = alloca i32, align 4
  store i32 2, i32* %call_arg_value, align 4
  call void @prini_main__lcompilers(i32* %call_arg_value, [1 x i8*] %mes)
  br label %return

return:                                           ; preds = %.entry
  ret void
}

define void @prini() {
.entry:
  %call_arg_value = alloca i32, align 4
  %mes = alloca %array*, align 8
  store %array* null, %array** %mes, align 8
  %arr_desc = alloca %array, align 8
  %0 = getelementptr %array, %array* %arr_desc, i32 0, i32 2
  %1 = alloca i32, align 4
  store i32 1, i32* %1, align 4
  %2 = load i32, i32* %1, align 4
  %3 = alloca %dimension_descriptor, i32 %2, align 8
  store %dimension_descriptor* %3, %dimension_descriptor** %0, align 8
  %4 = getelementptr %array, %array* %arr_desc, i32 0, i32 4
  store i32 1, i32* %4, align 4
  %5 = getelementptr %array, %array* %arr_desc, i32 0, i32 0
  store i8** null, i8*** %5, align 8
  store %array* %arr_desc, %array** %mes, align 8
  store i32 1, i32* %call_arg_value, align 4
  %6 = load %array*, %array** %mes, align 8
  call void @prini_main__lcompilers(i32* %call_arg_value, %array* %6)
  br label %return

return:                                           ; preds = %.entry
  ret void
}

define void @prini_main__lcompilers(i32* %entry__lcompilers, [1 x i8*] %mes) {
.entry:
  %0 = load i32, i32* %entry__lcompilers, align 4
  %1 = icmp eq i32 %0, 1
  br i1 %1, label %then, label %else

then:                                             ; preds = %.entry
  br label %goto_target

unreachable_after_goto:                           ; No predecessors!
  br label %ifcont

else:                                             ; preds = %.entry
  br label %ifcont

ifcont:                                           ; preds = %else, %unreachable_after_goto
  %2 = load i32, i32* %entry__lcompilers, align 4
  %3 = icmp eq i32 %2, 2
  br i1 %3, label %then1, label %else3

then1:                                            ; preds = %ifcont
  br label %goto_target5

unreachable_after_goto2:                          ; No predecessors!
  br label %ifcont4

else3:                                            ; preds = %ifcont
  br label %ifcont4

ifcont4:                                          ; preds = %else3, %unreachable_after_goto2
  br label %goto_target

goto_target:                                      ; preds = %ifcont4, %then
  br label %return

unreachable_after_return:                         ; No predecessors!
  br label %goto_target5

goto_target5:                                     ; preds = %unreachable_after_return, %then1
  br label %return

unreachable_after_return6:                        ; No predecessors!
  br label %return

return:                                           ; preds = %unreachable_after_return6, %goto_target5, %goto_target
  ret void
}
code generation error: asr_to_llvm: module failed verification. Error:
Call parameter type does not match function signature!
  %6 = load %array*, %array** %mes, align 8
 [1 x i8*]  call void @prini_main__lcompilers(i32* %call_arg_value, %array* %6)



Note: Please report unclear or confusing messages as bugs at
https://github.com/lfortran/lfortran/issues.

[Pranavchiku]

The above one is fixed, next we have is:

SUBROUTINE PRINI()
CHARACTER *1 MES(1)

RETURN
ENTRY PRIN(MES)
CALL  MESSPR(MES)
RETURN

END

% lfortran a.f90 --show-llvm --implicit-typing --implicit-interface
Internal Compiler Error: Unhandled exception
Traceback (most recent call last):
  File "/Users/pranavchiku/repos/lfortran/src/bin/lfortran.cpp", line 2254
    return emit_llvm(arg_file, lfortran_pass_manager,
  File "/Users/pranavchiku/repos/lfortran/src/bin/lfortran.cpp", line 847
    = fe.get_llvm(input, lm, pass_manager, diagnostics);
  File "/Users/pranavchiku/repos/lfortran/src/lfortran/fortran_evaluator.cpp", line 292
    Result<std::unique_ptr<LLVMModule>> res = get_llvm2(code, lm, pass_manager, diagnostics);
  File "/Users/pranavchiku/repos/lfortran/src/lfortran/fortran_evaluator.cpp", line 314
    diagnostics, lm.files.back().in_filename);
  File "/Users/pranavchiku/repos/lfortran/src/lfortran/fortran_evaluator.cpp", line 360
    compiler_options, run_fn, infile);
  File "/Users/pranavchiku/repos/lfortran/src/libasr/codegen/asr_to_llvm.cpp", line 9441
    } catch (const CodeGenError &e) {
  File "../libasr/asr.h", line 5059
  File "../libasr/asr.h", line 5035
  File "../libasr/asr.h", line 5060
  File "../libasr/asr.h", line 4768
  File "/Users/pranavchiku/repos/lfortran/src/libasr/codegen/asr_to_llvm.cpp", line 938
    visit_symbol(*item.second);
  File "../libasr/asr.h", line 5062
  File "../libasr/asr.h", line 4777
  File "/Users/pranavchiku/repos/lfortran/src/libasr/codegen/asr_to_llvm.cpp", line 3713
    visit_procedures(x);
  File "/Users/pranavchiku/repos/lfortran/src/libasr/codegen/asr_to_llvm.cpp", line 3910
    this->visit_stmt(*x.m_body[i]);
  File "../libasr/asr.h", line 5079
  File "../libasr/asr.h", line 4827
  File "/Users/pranavchiku/repos/lfortran/src/libasr/codegen/asr_to_llvm.cpp", line 8511
    args.insert(args.end(), args2.begin(), args2.end());
  File "/Users/pranavchiku/repos/lfortran/src/libasr/codegen/asr_to_llvm.cpp", line 7995
    } else {
  File "/Users/pranavchiku/repos/lfortran/src/libasr/codegen/asr_to_llvm.cpp", line 5142
    if( x->type == ASR::exprType::ArrayItem ||
  File "../libasr/asr.h", line 5126
  File "../libasr/asr.h", line 4934
  File "/Users/pranavchiku/repos/lfortran/src/libasr/codegen/asr_to_llvm.cpp", line 5078
    }
  File "/Users/pranavchiku/repos/lfortran/src/libasr/codegen/asr_to_llvm.cpp", line 5049
    tmp = llvm_utils->create_gep(tmp, 0);
  File "/Users/pranavchiku/repos/lfortran/src/libasr/codegen/llvm_array_utils.cpp", line 535
    return llvm_utils->create_gep(arr, 0);
  File "/Users/pranavchiku/repos/lfortran/src/libasr/codegen/llvm_utils.cpp", line 1360
    return LLVM::CreateGEP(*builder, ds, idx_vec);
  File "/Users/pranavchiku/repos/lfortran/src/libasr/codegen/llvm_utils.cpp", line 25
    LCOMPILERS_ASSERT(t->isPointerTy());
AssertFailed: t->isPointerTy()

[certik]

Perfect. Let me know if you need help.

[Pranavchiku]

I am not sure how to fix #3003 (comment), I am wrapping up today's work, will push to get it fixed by tomorrow.

[Pranavchiku]

Damnn! CI looks good, 🤞🏼

[certik]

I think this looks good. Thanks @Pranavchiku !

@czgdp1807 can you please also review this before we merge it?