From d622098bce7f7210d6d54417d863e1b66433e587 Mon Sep 17 00:00:00 2001
From: William Deegan <bill@baddogconsulting.com>
Date: Mon, 4 Sep 2023 02:02:01 +0000
Subject: [PATCH] Added logic to properly initilize SCons to use gfortran if
 tool gfortran is loaded. Also initialize FORTRAN properly to use -fPIC as it
 does for F77, F90,.... Patch initially from discord user maiphi

---
 SCons/Tool/gfortran.py                          | 13 +++++++++----
 test/Fortran/F03.py                             |  7 +++----
 test/Fortran/fixture/SConstruct_gfortran_shared |  3 +++
 test/Fortran/fixture/gfortran_shared.f          |  3 +++
 test/Fortran/gfortran.py                        | 15 +++++++++++----
 5 files changed, 29 insertions(+), 12 deletions(-)
 create mode 100644 test/Fortran/fixture/SConstruct_gfortran_shared
 create mode 100644 test/Fortran/fixture/gfortran_shared.f

diff --git a/SCons/Tool/gfortran.py b/SCons/Tool/gfortran.py
index cb55ad602..f438b9171 100644
--- a/SCons/Tool/gfortran.py
+++ b/SCons/Tool/gfortran.py
@@ -30,19 +30,24 @@ selection method.
 """
 
 from SCons.Util import CLVar
+from SCons.Tool.FortranCommon import add_all_to_env, add_fortran_to_env
 
-from . import fortran
+compilers = ['gfortran']
 
 
 def generate(env) -> None:
     """Add Builders and construction variables for gfortran."""
-    fortran.generate(env)
+
+    add_all_to_env(env)
+    add_fortran_to_env(env)
+
+    compiler = env.Detect(compilers) or 'gfortran'
 
     # fill in other dialects (FORTRAN dialect set by fortran.generate(),
     # but don't overwrite if they have been set manually.
-    for dialect in ['F77', 'F90', 'F95', 'F03', 'F08']:
+    for dialect in ['FORTRAN', 'F77', 'F90', 'F95', 'F03', 'F08']:
         if dialect not in env:
-            env[f'{dialect}'] = 'gfortran'
+            env[f'{dialect}'] = compiler
         if f'SH{dialect}' not in env:
             env[f'SH{dialect}'] = f'${dialect}'
 
diff --git a/test/Fortran/F03.py b/test/Fortran/F03.py
index ce56cc30b..0d4b9461c 100644
--- a/test/Fortran/F03.py
+++ b/test/Fortran/F03.py
@@ -1,6 +1,8 @@
 #!/usr/bin/env python
 #
-# __COPYRIGHT__
+# MIT License
+#
+# Copyright The SCons Foundation
 #
 # Permission is hereby granted, free of charge, to any person obtaining
 # a copy of this software and associated documentation files (the
@@ -20,9 +22,6 @@
 # LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 # OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 # WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-#
-
-__revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
 import TestSCons
 
diff --git a/test/Fortran/fixture/SConstruct_gfortran_shared b/test/Fortran/fixture/SConstruct_gfortran_shared
new file mode 100644
index 000000000..a063af860
--- /dev/null
+++ b/test/Fortran/fixture/SConstruct_gfortran_shared
@@ -0,0 +1,3 @@
+DefaultEnvironment(tools=[])
+env = Environment(tools = ['gfortran', 'gnulink'])
+env.SharedLibrary('gfortran_shared', ['gfortran_shared.f'])
diff --git a/test/Fortran/fixture/gfortran_shared.f b/test/Fortran/fixture/gfortran_shared.f
new file mode 100644
index 000000000..6efd8ffeb
--- /dev/null
+++ b/test/Fortran/fixture/gfortran_shared.f
@@ -0,0 +1,3 @@
+      SUBROUTINE gfortran_shared
+      WRITE(*,*) "Hi from subroutine gfortran_shared!"
+      END SUBROUTINE gfortran_shared
\ No newline at end of file
diff --git a/test/Fortran/gfortran.py b/test/Fortran/gfortran.py
index c3dec97fe..8d9b73129 100644
--- a/test/Fortran/gfortran.py
+++ b/test/Fortran/gfortran.py
@@ -1,6 +1,8 @@
 #!/usr/bin/env python
 #
-# __COPYRIGHT__
+# MIT License
+#
+# Copyright The SCons Foundation
 #
 # Permission is hereby granted, free of charge, to any person obtaining
 # a copy of this software and associated documentation files (the
@@ -20,9 +22,6 @@
 # LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 # OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 # WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-#
-
-__revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
 """
 Verify that the gfortran tool compiles a .f90 file to an executable,
@@ -98,6 +97,14 @@ test.must_exist(['modules', 'test2mod.mod'])
 
 test.up_to_date(arguments = '.')
 
+
+# Now test if shared library build works.
+test.file_fixture('fixture/gfortran_shared.f')
+test.file_fixture('fixture/SConstruct_gfortran_shared')
+test.run(arguments = '-f SConstruct_gfortran_shared')
+test.fail_test('gfortran ' not in test.stdout(), message="SCons didn't use gfortran")
+
+
 test.pass_test()
 
 # Local Variables:
-- 
2.11.4.GIT