[PATCH] D97201: [flang] Detect circularly defined interfaces of procedures

[Andrzej Warzynski via Phabricator via llvm-commits]

awarzynski added a comment.

In D97201#2593487 <https://reviews.llvm.org/D97201#2593487>, @kiranchandramohan wrote:

> @PeteSteinfeld
>
> The aarch64 flang buildbots are failing  since this commit.
> https://lab.llvm.org/buildbot/#/builders/32/builds/3480
> The x86 buildbot is passing. https://lab.llvm.org/buildbot/#/builders/132
>
> From the failure it looks like a test expectation issue. Not sure, but it could be that the order/start/direction of the cycle could be different for aarch64, x86.

I believe that the problem stems from the switch from `std::set` to `std::unordered_set`. As a result, the order in which things are printed is implementation-defined (and will differ between platforms). However, that switch is also part of the fix here - I assume that reverting it is not desirable.

One other alternative would be to leverage FileCheck <https://llvm.org/docs/CommandGuide/FileCheck.html> and to use regex patterns in the tests. That would make the test less fragile, but I'm under the impression that people do prefer to use `test_errors.sh` instead (previous discussion here <https://lists.llvm.org/pipermail/flang-dev/2020-July/000407.html>). Just to demonstrate how a ported test would look, I've updated //resolve102.f90// and pasted it at the bottom of this message (passes on AArch64).

@PeteSteinfeld , thank you for working on this! As this is causing a breakage in 6 out of 8 of Flang's public buildbots, I will revert this for now (I'm not sure what the fix should be). Please let me know if I can help to re-land this change!

**PORTED  TEST**

  ! RUN: not %f18 %s 2>&1 | FileCheck %s
  
  ! Tests for circularly defined procedures
  ! CHECK: Procedure 'sub' is recursively defined.  Procedures in the cycle: '{{p2|sub}}', '{{p2|sub}}'
  subroutine sub(p2)
    PROCEDURE(sub) :: p2
  
    call sub()
  end subroutine
  
  subroutine circular
    ! CHECK: Procedure 'p' is recursively defined.  Procedures in the cycle: '{{p|p2|sub}}', '{{p|p2|sub}}', '{{p|p2|sub}}'
    procedure(sub) :: p
  
    call p(sub)
  
    contains
      subroutine sub(p2)
        procedure(p) :: p2
      end subroutine
  end subroutine circular
  
  program iface
    ! CHECK: Procedure 'p' is recursively defined.  Procedures in the cycle: '{{p|p2|sub}}', '{{p|p2|sub}}', '{{p|p2|sub}}'
    procedure(sub) :: p
    interface
      subroutine sub(p2)
        import p
        procedure(p) :: p2
      end subroutine
    end interface
    call p(sub)
  end program
  
  Program mutual
    Procedure(sub1) :: p
  
    Call p(sub)
  
    contains
      ! CHECK:: Procedure 'sub1' is recursively defined.  Procedures in the cycle: '{{arg|p|sub1}}', '{{arg|p|sub1}}', '{{arg|p|sub1}}'
      Subroutine sub1(arg)
        procedure(sub1) :: arg
      End Subroutine
  
      Subroutine sub(p2)
        Procedure(sub1) :: p2
      End Subroutine
  End Program
  
  Program mutual1
    Procedure(sub1) :: p
  
    Call p(sub)
  
    contains
      ! CHECK:: Procedure 'sub1' is recursively defined.  Procedures in the cycle: '{{p2|sub|arg|p|sub1}}', '{{p2|sub|arg|p|sub1}}', '{{p2|sub|arg|p|sub1}}', '{{p2|sub|arg|p|sub1}}', '{{p2|sub|arg|p|sub1}}'
      Subroutine sub1(arg)
        procedure(sub) :: arg
      End Subroutine
  
      Subroutine sub(p2)
        Procedure(sub1) :: p2
      End Subroutine
  End Program
  
  program twoCycle
    ! CHECK:: The interface for procedure 'p1' is recursively defined
    ! CHECK:: The interface for procedure 'p2' is recursively defined
    procedure(p1) p2
    procedure(p2) p1
    call p1
    call p2
  end program
  
  program threeCycle
    ! CHECK:: The interface for procedure 'p1' is recursively defined
    ! CHECK:: The interface for procedure 'p2' is recursively defined
    procedure(p1) p2
    ! CHECK:: The interface for procedure 'p3' is recursively defined
    procedure(p2) p3
    procedure(p3) p1
    call p1
    call p2
    call p3
  end program


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