Type Error in type_check_Ctup.py

[Trac91iu]

I’ve been testing the tuple but keep encountering the following error:
Traceback (most recent call last):
File "/home/autograder/working_dir/run-tuple-test.py", line 22, in
run_one_test(os.getcwd() + '/tests/' + lang + '/' + test + '.py', lang,
File "/home/autograder/working_dir/utils.py", line 1606, in run_one_test
return compile_and_test(compiler, compiler_name, type_check_dict,
File "/home/autograder/working_dir/utils.py", line 1418, in compile_and_test
type_check_dictpassname
File "/home/autograder/working_dir/type_check_Cif.py", line 115, in type_check
self.type_check_stmts(ss[:-1], env)
File "/home/autograder/working_dir/type_check_Cif.py", line 78, in type_check_stmts
self.type_check_stmt(s, env)
File "/home/autograder/working_dir/type_check_Ctup.py", line 76, in type_check_stmt
return super().type_check_stmt(s, env)
File "/home/autograder/working_dir/type_check_Cif.py", line 83, in type_check_stmt
t = self.type_check_exp(value, env)
File "/home/autograder/working_dir/type_check_Ctup.py", line 58, in type_check_exp
return super().type_check_exp(e, env)
File "/home/autograder/working_dir/type_check_Cif.py", line 74, in type_check_exp
raise Exception('error in type_check_exp, unexpected ' + repr(e))
Exception: error in type_check_exp, unexpected GlobalValue(name='free_ptr')

After investigating, I looked into type_check_Ctup.py and noticed that the type_check_exp function doesn't seem to handle the GlobalValue case. When I assign a GlobalValue to a variable, Assign takes exp as an input, and GlobalValue appears to be a type of exp as well.

If the remove complex operand give statement "tmp.4 = (free_ptr + 32)", it works fine. But according to the slides and the python-book, they both suggest using "tmp.3 = free_ptr". Given the grammar (Figure 7.12), "tmp.3 = free_ptr" should also pass the type checker. Therefore, would it be better to add a case in the type_check_exp function in type_check_Ctup.py to handle the GlobalValue? For example: case GlobalValue(name): return self.type_check_atm(e, env)).

[DarshalShetty]

@jsiek this issue is for the Python support code, even though it's been posted on the Racket support code repo.

Here is the complete error trace for @Trac91iu's compiler when run on the get_add test in the tuple test suite:

# source program: get_add

    t = (38, 2,)
    print(((t[0] + t[1]) + len(t)))


Module([  Assign([Name('t')], Tuple([Constant(38), Constant(2)])),   Expr(Call(Name('print'), [BinOp(BinOp(Subscript(Name('t'), Constant(0), <ast.Load object at 0x7f0f91e7a3e0>), Add(), Subscript(Name('t'), Constant(1), <ast.Load object at 0x7f0f91e7a3e0>)), Add(), Call(Name('len'), [Name('t')]))]))])


# type checking source program


# shrink

    t = (38, 2,)
    print(((t[0] + t[1]) + len(t)))


compiler tuples success on pass shrink on test
/home/celebrimbor/Code/compilers/python-compiler/tests/tuple/get_add


# expose_allocation

    t = {
      init.0 = 38
      init.1 = 2
      if (free_ptr + 32) < fromspace_end:
      else:
        collect(32)
      alloc.2 = allocate(32,tuple[int,int])
      alloc.2[0] = init.0
      alloc.2[1] = init.1
      produce alloc.2}
    print(((t[0] + t[1]) + len(t)))

type checking after expose_allocation

type checking passed
1c1
< 72
---
> 42
compiler tuples failed pass expose_allocation on test:
/home/celebrimbor/Code/compilers/python-compiler/tests/tuple/get_add


# remove_complex_operands

    t = {
      init.0 = 38
      init.1 = 2
      tmp.3 = free_ptr
      tmp.4 = (tmp.3 + 32)
      tmp.5 = fromspace_end
      if tmp.4 < tmp.5:
      else:
        collect(32)
      alloc.2 = allocate(32,tuple[int,int])
      alloc.2[0] = init.0
      alloc.2[1] = init.1
      produce alloc.2}
    tmp.6 = t[0]
    tmp.7 = t[1]
    tmp.8 = (tmp.6 + tmp.7)
    tmp.9 = len(t)
    tmp.10 = (tmp.8 + tmp.9)
    print(tmp.10)

Module([  Assign([Name('t')], Begin(body=[  Assign([Name('init.0')], Constant(38)),   Assign([Name('init.1')], Constant(2)),   Assign([Name('tmp.3')], GlobalValue(name='free_ptr')),   Assign([Name('tmp.4')], BinOp(Name('tmp.3'), Add(), Constant(32))),   Assign([Name('tmp.5')], GlobalValue(name='fromspace_end')), If(Compare(Name('tmp.4'), [Lt()], [Name('tmp.5')]), [], [Collect(size=32)]),   Assign([Name('alloc.2')], Allocate(length=32, ty=TupleType(types=[IntType(), IntType()]))),   Assign([Subscript(Name('alloc.2'), Constant(0), <ast.Store object at 0x7f0f9132b460>)], Name('init.0')),   Assign([Subscript(Name('alloc.2'), Constant(1), <ast.Store object at 0x7f0f9132ba00>)], Name('init.1'))], result=Name('alloc.2'))),   Assign([Name('tmp.6')], Subscript(Name('t'), Constant(0), <ast.Load object at 0x7f0f91e7a3e0>)),   Assign([Name('tmp.7')], Subscript(Name('t'), Constant(1), <ast.Load object at 0x7f0f91e7a3e0>)),   Assign([Name('tmp.8')], BinOp(Name('tmp.6'), Add(), Name('tmp.7'))),   Assign([Name('tmp.9')], Call(Name('len'), [Name('t')])),   Assign([Name('tmp.10')], BinOp(Name('tmp.8'), Add(), Name('tmp.9'))),   Expr(Call(Name('print'), [Name('tmp.10')]))])
type checking after remove_complex_operands

type checking passed
1c1
< 72
---
> 42
compiler tuples failed pass remove_complex_operands on test:
/home/celebrimbor/Code/compilers/python-compiler/tests/tuple/get_add


# explicate_control

block.11:
    alloc.2 = allocate(32,tuple[int,int])
    alloc.2:tuple[int,int][0] = init.0
    alloc.2:tuple[int,int][1] = init.1
    t = alloc.2
    tmp.6 = t[0]
    tmp.7 = t[1]
    tmp.8 = (tmp.6 + tmp.7)
    tmp.9 = len(t)
    tmp.10 = (tmp.8 + tmp.9)
    print(tmp.10)
    return 0

block.12:
    goto block.11

block.13:
    collect(32)
    goto block.11

start:
    init.0 = 38
    init.1 = 2
    tmp.3 = free_ptr
    tmp.4 = (tmp.3 + 32)
    tmp.5 = fromspace_end
    if tmp.4 < tmp.5:
      goto block.12
    else:
      goto block.13


CProgram(body={'block.11': [  Assign([Name('alloc.2')], Allocate(length=32, ty=TupleType(types=[IntType(), IntType()]))),   Assign([Subscript(Name('alloc.2'), Constant(0), <ast.Store object at 0x7f0f9132b460>)], Name('init.0')),   Assign([Subscript(Name('alloc.2'), Constant(1), <ast.Store object at 0x7f0f9132ba00>)], Name('init.1')),   Assign([Name('t')], Name('alloc.2')),   Assign([Name('tmp.6')], Subscript(Name('t'), Constant(0), <ast.Load object at 0x7f0f91e7a3e0>)),   Assign([Name('tmp.7')], Subscript(Name('t'), Constant(1), <ast.Load object at 0x7f0f91e7a3e0>)),   Assign([Name('tmp.8')], BinOp(Name('tmp.6'), Add(), Name('tmp.7'))),   Assign([Name('tmp.9')], Call(Name('len'), [Name('t')])),   Assign([Name('tmp.10')], BinOp(Name('tmp.8'), Add(), Name('tmp.9'))),   Expr(Call(Name('print'), [Name('tmp.10')])),   Return(Constant(0))], 'block.12': [Goto(label='block.11')], 'block.13': [Collect(size=32), Goto(label='block.11')], 'start': [  Assign([Name('init.0')], Constant(38)),   Assign([Name('init.1')], Constant(2)),   Assign([Name('tmp.3')], GlobalValue(name='free_ptr')),   Assign([Name('tmp.4')], BinOp(Name('tmp.3'), Add(), Constant(32))),   Assign([Name('tmp.5')], GlobalValue(name='fromspace_end')), If(Compare(Name('tmp.4'), [Lt()], [Name('tmp.5')]), [Goto(label='block.12')], [Goto(label='block.13')])]})
type checking after explicate_control

Traceback (most recent call last):
  File "/home/celebrimbor/Code/compilers/python-compiler/run-tuple-test.py", line 22, in <module>
    run_one_test(os.getcwd() + '/tests/' + lang + '/' + test + '.py', lang,
  File "/home/celebrimbor/Code/compilers/python-compiler/../python-student-support-code/utils.py", line 1606, in run_one_test
    return compile_and_test(compiler, compiler_name, type_check_dict,
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/celebrimbor/Code/compilers/python-compiler/../python-student-support-code/utils.py", line 1418, in compile_and_test
    type_check_dict[passname](program)
  File "/home/celebrimbor/Code/compilers/python-compiler/../python-student-support-code/type_check_Cif.py", line 115, in type_check
    self.type_check_stmts(ss[:-1], env)
  File "/home/celebrimbor/Code/compilers/python-compiler/../python-student-support-code/type_check_Cif.py", line 78, in type_check_stmts
    self.type_check_stmt(s, env)
  File "/home/celebrimbor/Code/compilers/python-compiler/../python-student-support-code/type_check_Ctup.py", line 76, in type_check_stmt
    return super().type_check_stmt(s, env)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/celebrimbor/Code/compilers/python-compiler/../python-student-support-code/type_check_Cif.py", line 83, in type_check_stmt
    t = self.type_check_exp(value, env)
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/celebrimbor/Code/compilers/python-compiler/../python-student-support-code/type_check_Ctup.py", line 58, in type_check_exp
    return super().type_check_exp(e, env)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/celebrimbor/Code/compilers/python-compiler/../python-student-support-code/type_check_Cif.py", line 74, in type_check_exp
    raise Exception('error in type_check_exp, unexpected ' + repr(e))
Exception: error in type_check_exp, unexpected GlobalValue(name='free_ptr')

[DarshalShetty]

@Trac91iu's solution to modify type_check_exp function in type_check_Ctup.py seems to stop the type-checker from erroring out for statements like x=free_ptr. Here is what this change would look like:

  def type_check_exp(self, e, env):
    match e:
        case GlobalValue(name):
          return self.type_check_atm(e, env)
         ...

This would make the example code in the textbook and the lecture slides type-check successfully as well. I believe this bug was introduced in this commit: IUCompilerCourse/python-student-support-code@04dbae2. Therefore, it seems like we need to handle the GlobalValue case in order to preserve the behavior of the type-checker before this commit was made.

Let me know if I should push this fix to the Python support code repository @jsiek.

[jsiek]

Yes, did the same as you suggest. (Didn't see your comment until after I already pushed.)