See attached patch. This bug found when trying to build the Formal package.
Developed with with Assistance from Claude Sonnet 4.6. Two new testsuite files
provided. The change wiggled on a few exiting test cases.
Regression tested on x86_64 Linux.
OK for mainline? What about backport?
Regards,
Jerry
----
fortran: module-contained PRIVATE procedures must have global
ELF linkage [PR125430]
gcc/fortran/ChangeLog:
PR fortran/125430
* trans-decl.cc (build_function_decl): Set TREE_PUBLIC for all
module-contained procedures so submodules compiled as separate
translation units can reach them via host association. Also set
DECL_VISIBILITY to VISIBILITY_HIDDEN for PRIVATE procedures,
matching the existing treatment of module variables.
gcc/testsuite/ChangeLog:
PR fortran/125430
* gfortran.dg/module_private_2.f90: Remove scan-tree-dump-times
assertion for 'priv'; PRIVATE module procedures now have global
linkage with hidden visibility and are no longer optimized away.
* gfortran.dg/public_private_module_2.f90: Add xfail markers to
scan-assembler-not for 'two' and 'six'; update comment to mention
procedures alongside variables.
* gfortran.dg/public_private_module_7.f90: Add xfail marker to
scan-assembler-not for '__m_common_attrs_MOD_other'.
* gfortran.dg/public_private_module_8.f90: Add xfail marker to
scan-assembler-not for '__m_MOD_myotherlen'.
* gfortran.dg/submodule_private_host.f90: New test.
* gfortran.dg/submodule_private_host_aux.f90: New auxiliary file.
* gfortran.dg/warn_unused_function_2.f90: Remove 'defined but not
used' expectation for s1; PRIVATE module procedures now have
global linkage and no longer trigger the unused-function warning.
Assisted by: Claude Sonnet 4.6
---From 1a42c92126a0414079f69e0e5d4d974f2ffc4b9d Mon Sep 17 00:00:00 2001
From: Jerry DeLisle <[email protected]>
Date: Fri, 22 May 2026 21:56:34 -0700
Subject: [PATCH] fortran: module-contained PRIVATE procedures must have global
ELF linkage [PR125430]
gcc/fortran/ChangeLog:
PR fortran/125430
* trans-decl.cc (build_function_decl): Set TREE_PUBLIC for all
module-contained procedures so submodules compiled as separate
translation units can reach them via host association. Also set
DECL_VISIBILITY to VISIBILITY_HIDDEN for PRIVATE procedures,
matching the existing treatment of module variables.
gcc/testsuite/ChangeLog:
PR fortran/125430
* gfortran.dg/module_private_2.f90: Remove scan-tree-dump-times
assertion for 'priv'; PRIVATE module procedures now have global
linkage with hidden visibility and are no longer optimized away.
* gfortran.dg/public_private_module_2.f90: Add xfail markers to
scan-assembler-not for 'two' and 'six'; update comment to mention
procedures alongside variables.
* gfortran.dg/public_private_module_7.f90: Add xfail marker to
scan-assembler-not for '__m_common_attrs_MOD_other'.
* gfortran.dg/public_private_module_8.f90: Add xfail marker to
scan-assembler-not for '__m_MOD_myotherlen'.
* gfortran.dg/submodule_private_host.f90: New test.
* gfortran.dg/submodule_private_host_aux.f90: New auxiliary file.
* gfortran.dg/warn_unused_function_2.f90: Remove 'defined but not
used' expectation for s1; PRIVATE module procedures now have
global linkage and no longer trigger the unused-function warning.
Assisted by: Claude Sonnet 4.6
---
gcc/fortran/trans-decl.cc | 24 +++++++++++++--
.../gfortran.dg/module_private_2.f90 | 3 +-
.../gfortran.dg/public_private_module_2.f90 | 8 +++--
.../gfortran.dg/public_private_module_7.f90 | 2 +-
.../gfortran.dg/public_private_module_8.f90 | 2 +-
.../gfortran.dg/submodule_private_host.f90 | 29 +++++++++++++++++++
.../submodule_private_host_aux.f90 | 17 +++++++++++
.../gfortran.dg/warn_unused_function_2.f90 | 2 +-
8 files changed, 78 insertions(+), 9 deletions(-)
create mode 100644 gcc/testsuite/gfortran.dg/submodule_private_host.f90
create mode 100644 gcc/testsuite/gfortran.dg/submodule_private_host_aux.f90
diff --git a/gcc/fortran/trans-decl.cc b/gcc/fortran/trans-decl.cc
index 1bcbfdfd2c9..969fe75b946 100644
--- a/gcc/fortran/trans-decl.cc
+++ b/gcc/fortran/trans-decl.cc
@@ -2575,11 +2575,31 @@ build_function_decl (gfc_symbol * sym, bool global)
&& flag_module_private)))
sym->attr.access = ACCESS_PRIVATE;
+ /* A procedure contained directly in a module must be globally addressable
+ even when its Fortran access is PRIVATE: a submodule compiled as a
+ separate translation unit can reach it via host association. The
+ Fortran PRIVATE attribute restricts USE-association visibility, not
+ ELF symbol linkage. */
+ bool in_module_contains = sym->module && sym->ns->proc_name
+ && sym->ns->proc_name->attr.flavor == FL_MODULE;
+
if (!current_function_decl
&& !sym->attr.entry_master && !sym->attr.is_main_program
&& (sym->attr.access != ACCESS_PRIVATE || sym->binding_label
- || sym->attr.public_used))
- TREE_PUBLIC (fndecl) = 1;
+ || sym->attr.public_used || in_module_contains))
+ {
+ TREE_PUBLIC (fndecl) = 1;
+ /* Mirror the variable treatment (see gfc_finish_var_decl): PRIVATE
+ module procedures get global linkage but hidden visibility so the
+ symbol is reachable from submodules in the same link without being
+ exported to external DSOs. */
+ if (in_module_contains && sym->attr.access == ACCESS_PRIVATE
+ && !sym->attr.public_used)
+ {
+ DECL_VISIBILITY (fndecl) = VISIBILITY_HIDDEN;
+ DECL_VISIBILITY_SPECIFIED (fndecl) = true;
+ }
+ }
if (sym->attr.referenced || sym->attr.entry_master)
TREE_USED (fndecl) = 1;
diff --git a/gcc/testsuite/gfortran.dg/module_private_2.f90 b/gcc/testsuite/gfortran.dg/module_private_2.f90
index 58dbb1e23fe..926da364182 100644
--- a/gcc/testsuite/gfortran.dg/module_private_2.f90
+++ b/gcc/testsuite/gfortran.dg/module_private_2.f90
@@ -29,6 +29,7 @@ contains
b => export1
end subroutine pub
end module m
-! { dg-final { scan-tree-dump-times "priv" 0 "optimized" } }
+! priv now has TREE_PUBLIC (VISIBILITY_HIDDEN) for submodule host-association,
+! so it is no longer optimized away.
! { dg-final { scan-tree-dump-times "export1 \\(\\)" 1 "optimized" } }
! { dg-final { scan-tree-dump-times "export2 \\(\\)" 1 "optimized" } }
diff --git a/gcc/testsuite/gfortran.dg/public_private_module_2.f90 b/gcc/testsuite/gfortran.dg/public_private_module_2.f90
index 87276ccdfd1..e37cfbd57cc 100644
--- a/gcc/testsuite/gfortran.dg/public_private_module_2.f90
+++ b/gcc/testsuite/gfortran.dg/public_private_module_2.f90
@@ -19,8 +19,10 @@ module mod
integer, bind(C,name='') :: qq
end module mod
-! The two xfails below have appeared with the introduction of submodules. 'iii' and
+! The xfails below have appeared with the introduction of submodules. 'iii' and
! 'mmm' now are TREE_PUBLIC but has DECL_VISIBILITY (decl) = VISIBILITY_HIDDEN set.
+! Similarly 'two' and 'six' (PRIVATE procedures) now have TREE_PUBLIC +
+! VISIBILITY_HIDDEN so that submodules can reach them via host association.
! { dg-final { scan-assembler "__mod_MOD_aa" } }
! { dg-final { scan-assembler-not "iii" { xfail *-*-* } } }
@@ -64,11 +66,11 @@ CONTAINS
END MODULE
! { dg-final { scan-assembler "__m_MOD_one" } }
-! { dg-final { scan-assembler-not "two" } }
+! { dg-final { scan-assembler-not "two" { xfail *-*-* } } }
! { dg-final { scan-assembler "three" } }
! { dg-final { scan-assembler-not "four" } }
! { dg-final { scan-assembler "five" } }
-! { dg-final { scan-assembler-not "six" } }
+! { dg-final { scan-assembler-not "six" { xfail *-*-* } } }
! { dg-final { scan-assembler "seven" } }
! { dg-final { scan-assembler "nine" } }
! { dg-final { scan-assembler "__m_MOD_ten" } }
diff --git a/gcc/testsuite/gfortran.dg/public_private_module_7.f90 b/gcc/testsuite/gfortran.dg/public_private_module_7.f90
index d03b7047a12..4b62d23dc6f 100644
--- a/gcc/testsuite/gfortran.dg/public_private_module_7.f90
+++ b/gcc/testsuite/gfortran.dg/public_private_module_7.f90
@@ -25,5 +25,5 @@ contains
end function get_key
end module m_common_attrs
-! { dg-final { scan-assembler-not "__m_common_attrs_MOD_other" } }
+! { dg-final { scan-assembler-not "__m_common_attrs_MOD_other" { xfail *-*-* } } }
! { dg-final { scan-assembler "__m_common_attrs_MOD_get_key_len" } }
diff --git a/gcc/testsuite/gfortran.dg/public_private_module_8.f90 b/gcc/testsuite/gfortran.dg/public_private_module_8.f90
index bfc1b368f46..addf93440ab 100644
--- a/gcc/testsuite/gfortran.dg/public_private_module_8.f90
+++ b/gcc/testsuite/gfortran.dg/public_private_module_8.f90
@@ -44,6 +44,6 @@ contains
end subroutine bar
end module m
-! { dg-final { scan-assembler-not "__m_MOD_myotherlen" } }
+! { dg-final { scan-assembler-not "__m_MOD_myotherlen" { xfail *-*-* } } }
! { dg-final { scan-assembler "__m_MOD_bar" } }
! { dg-final { scan-assembler "__m_MOD_mylen" } }
diff --git a/gcc/testsuite/gfortran.dg/submodule_private_host.f90 b/gcc/testsuite/gfortran.dg/submodule_private_host.f90
new file mode 100644
index 00000000000..e50faaad111
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/submodule_private_host.f90
@@ -0,0 +1,29 @@
+! { dg-do run }
+! { dg-additional-sources submodule_private_host_aux.f90 }
+!
+! PR fortran/125430
+!
+! Module-contained procedures with PRIVATE access must retain global ELF
+! linkage so that submodules compiled as separate translation units can
+! reach them via host association.
+
+module m
+ implicit none
+ private
+ public :: pub
+
+ interface
+ module subroutine pub(x)
+ double precision, intent(out) :: x
+ end subroutine
+ end interface
+
+contains
+
+ pure function priv(n) result(x)
+ integer, intent(in) :: n
+ double precision :: x
+ x = dble(n) * 0.5d0
+ end function
+
+end module
diff --git a/gcc/testsuite/gfortran.dg/submodule_private_host_aux.f90 b/gcc/testsuite/gfortran.dg/submodule_private_host_aux.f90
new file mode 100644
index 00000000000..e237cf2650c
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/submodule_private_host_aux.f90
@@ -0,0 +1,17 @@
+! Auxiliary file for submodule_private_host.f90
+! { dg-skip-if "" { *-*-* } }
+submodule(m) ms
+ implicit none
+contains
+ module procedure pub
+ x = priv(6)
+ end procedure
+end submodule
+
+program p
+ use m, only : pub
+ implicit none
+ double precision x
+ call pub(x)
+ if (abs(x - 3.0d0) > 1d-10) stop 1
+end program
diff --git a/gcc/testsuite/gfortran.dg/warn_unused_function_2.f90 b/gcc/testsuite/gfortran.dg/warn_unused_function_2.f90
index 43b211e57bf..894a343b75c 100644
--- a/gcc/testsuite/gfortran.dg/warn_unused_function_2.f90
+++ b/gcc/testsuite/gfortran.dg/warn_unused_function_2.f90
@@ -13,7 +13,7 @@ module m
contains
- subroutine s1 ! { dg-warning "defined but not used" }
+ subroutine s1
call s2(s3)
contains
subroutine s4 ! { dg-warning "defined but not used" }
--
2.54.0
