Code review please - top urgent

[Anobium]

I need a code review. I have changed a fundamental part of the compiler to resolve an issue.

This has take two long days to resolve. :-(

If I get this incorrect the compiler with fall over with bad asm.

If you can do code review - ping me.

Evan

---

The issue reported: The ASM code generated was different when a comment is the last line of code before an END SUB, and the code is the same when comments are removed from the program.

Code Example 1

#chip 16f88, 4
#option explicit

Sub _FN2
End Sub

Sub _FN1
  _FN2

End Sub

_FN1

Code Example 2

#chip 16f88, 4
#option explicit

Sub _FN2
End Sub

Sub _FN1
   _FN2
'~
End Sub

_FN1

The only difference is the comment at the end of _FN1 before the End Sub.

Code example 1 generated a call _fn1 & return and Code example 1 generated a goto _fn1 with no return (which is the intent).

---

With assmebly.bi line 235

Was

'Check for subs that have a call as the last instruction
  'Turn call into a goto
  'If call is last instruction and always runs, no need for a return at the end either
  'Get last line of sub
  CompSub->HasFinalGoto = 0
  CompSub->FinalGotoDest = ""
  CurrLine = CompSub->CodeStart
  Do While CurrLine->Next <> 0
    CurrLine = CurrLine->Next
  Loop
  LastLine = CurrLine
  'Get line before last
  CheckLine = LastLine->Prev
  If CheckLine <> 0 Then
    Do While (Left(CheckLine->Value, 1) = ";" Or Left(CheckLine->Value, 8) = "PRESERVE") AND CheckLine->Prev <> 0
      CheckLine = CheckLine->Prev
    Loop
  End If

now

 'Check for subs that have a call as the last instruction
  'Turn call into a goto
  'If call is last instruction and always runs, no need for a return at the end either
  'Get last line of sub
  CompSub->HasFinalGoto = 0
  CompSub->FinalGotoDest = ""
  'Restart the code list
  CurrLine = CompSub->CodeStart
  'Do while has data in code list
  Do While CurrLine->Next <> 0
    'While has code in code list, set to next code line
    CurrLine = CurrLine->Next
  Loop

  'Handle last line... it could be a comment therefore PRESERVEd
  'Do while the current code line is PRESERVEd
  Do while Left(CurrLine->Value, 8) = "PRESERVE"
   'if PREVious code is NOT a PRESERVEd line then get the PREVious line as the current line
    If Left(CurrLine->Prev->Value, 8) <> "PRESERVE" then
      CurrLine = CurrLine->Prev
    End if
  Loop

  LastLine = CurrLine
  'Get line before last
  CheckLine = LastLine->Prev
  If CheckLine <> 0 Then
    Do While (Left(CheckLine->Value, 1) = ";" Or Left(CheckLine->Value, 8) = "PRESERVE") AND CheckLine->Prev <> 0
      CheckLine = CheckLine->Prev
    Loop
  End If

[Anobium]

My initial attempt did break the compiler. It caused an indefinite loop, so, the compiler never completed.

New attempt with update code. With an additional test to check that the list is not pass the top extent of list.

  'Handle last line... it could be a comment therefore PRESERVEd
  'Do while the current code line is PRESERVEd
  Do while Left(CurrLine->Value, 8) = "PRESERVE"
   'if PREVious code is NOT a PRESERVEd line then get the PREVious line as the current line, and, check that we are not at the top of the list
    If Left(CurrLine->Prev->Value, 8) <> "PRESERVE" and CurrLine->Prev <> 0 then
      CurrLine = CurrLine->Prev
    Else
      Exit Do
    End if
    print CurrLine->Value
  Loop