[Flang] Fix argument mismatch issue

[kiranchandramohan]

When functions in different modules have the same name, it causes semantic checks to be confused. Using the wrong function signature for checks can cause the arguments to be mismatched. A reproducer is given below.

module aString
  implicit none
  Type string
    character(len=1),dimension(:),pointer :: c
  End Type string
  interface clean; module procedure clean_; end interface
contains
  subroutine clean_(str)
    implicit none
    type(string), intent(inout) :: str
  end subroutine clean_
end module

module aList
implicit none
Type list
  character(len=1),dimension(:),pointer :: bf
  integer,       dimension(:,:),pointer :: lc
End Type list
interface clean; module procedure clean_; end interface
contains
subroutine clean_(aList, stat)
implicit none
type(list),        intent(inout) :: aList
integer, optional, intent(out)   :: stat
end subroutine clean_
end module

module tmp_mod
use aString             ,only: a_string             => string
use aString             ,only: a_string_clean       => clean
use aList               ,only: a_list               => list
use aList               ,only: a_list_clean         => clean
end module

module flds
  use tmp_mod
  implicit none
contains
  subroutine sb()
    type(a_string) :: tmpOStr
    type(a_list)   :: tmpIstr
    call a_list_clean(tmpIstr)
    call a_string_clean(tmpOStr)
end subroutine
end module

This issue was found while investigating 527.cam4_r.

[llvmbot]

@llvm/issue-subscribers-flang-frontend

[klausler]

Here's a patch that might help you advance to the next problem in that code:

diff --git a/flang/lib/Semantics/expression.cpp b/flang/lib/Semantics/expression.cpp
index 9f9107ea..dcf92101 100644
--- a/flang/lib/Semantics/expression.cpp
+++ b/flang/lib/Semantics/expression.cpp
@@ -2207,6 +2207,7 @@ const Symbol &ExpressionAnalyzer::AccessSpecific(
     // Create a renaming USE of the specific procedure.
     auto rename{context_.SaveTempName(
         used->symbol().owner().GetName().value().ToString() + "$" +
+        specific.owner().GetName().value().ToString() + "$" +
         specific.name().ToString())};
     return *const_cast<semantics::Scope &>(scope)
                 .try_emplace(rename, specific.attrs(),
diff --git a/flang/test/Semantics/modfile39.f90 b/flang/test/Semantics/modfile39.f90
index 6041d6cc..fbbd6ae4 100644
--- a/flang/test/Semantics/modfile39.f90
+++ b/flang/test/Semantics/modfile39.f90
@@ -36,11 +36,11 @@ end module
 !Expect: m2.mod
 !module m2
 !use m1,only:gen
-!use m1,only:m1$priv=>priv
-!private::m1$priv
+!use m1,only:m1$m1$priv=>priv
+!private::m1$m1$priv
 !contains
 !subroutine s(a)
-!real(4)::a(1_8:int(m1$priv(1_4),kind=8))
+!real(4)::a(1_8:int(m1$m1$priv(1_4),kind=8))
 !end
 !end

[klausler]

Does that patch solve your bug?

[kiranchandramohan]

Thanks @klausler. Yes, it fixed the issue in this bug as well as in the benchmark. But as you say there are other issues.

[klausler]

I don't think that I know anything or wrote anything about "other issues". What are they?

[kiranchandramohan]

The other issues in cam4 seem to be in the lowering/MLIR area, at least the failures are coming from there. I will file separate issues for these.

[banach-space]

@klausler Thanks for the fix! Are you planning to merge it? Once that's in tree, we can close this ticket.

[kiranchandramohan]

Patch is here: https://reviews.llvm.org/D127790