PR modula2/121629: adding third party modules

This patch makes it easier to add third party modules.
cc1gm2 now appends the search directory prefix/include/m2
to the search path for non dialect specific modules.
Prior to this it appends the dialect specific subdirectories
{m2pim,m2iso,m2log,m2min} with the appropriate dialect pathname.
The patch also includes a new option -fm2-pathname-root=prefix
which allow additional prefix/m2 directories to be searched
before the default.

gcc/ChangeLog:

	PR modula2/121629
	* doc/gm2.texi (Module Search Path): New section.
	(Compiler options): New option -fm2-pathname-root=.
	New option -fm2-pathname-rootI.

gcc/m2/ChangeLog:

	PR modula2/121629
	* gm2-compiler/PathName.mod: Add copyright notice.
	* gm2-lang.cc (named_path): Add field lib_root.
	(push_back_Ipath): Set lib_root false.
	(push_back_lib_root): New function.
	(get_dir_sep_size): Ditto.
	(add_path_component): Ditto.
	(add_one_import_path): Ditto.
	(add_non_dialect_specific_path): Ditto.
	(foreach_lib_gen_import_path): Ditto.
	(get_module_source_dir): Ditto.
	(add_default_include_paths): Ditto.
	(assign_flibs): Ditto.
	(m2_pathname_root): Ditto.
	(add_m2_import_paths): Remove function.
	(gm2_langhook_post_options): Call assign_flibs.
	Check np.lib_root and call foreach_lib_gen_import_path.
	Replace call to add_m2_import_paths with a call to
	add_default_include_paths.
	(gm2_langhook_handle_option): Add case OPT_fm2_pathname_rootI_.
	* gm2spec.cc (named_path): Add field lib_root.
	(push_back_Ipath): Set lib_root false.
	(push_back_lib_root): New function.
	(add_m2_I_path): Add OPT_fm2_pathname_rootI_ option
	if np.lib_root.
	(lang_specific_driver): Add case OPT_fm2_pathname_root_.
	* lang.opt (fm2-pathname-root=): New option.
	(fm2-pathname-rootI=): Ditto.

gcc/testsuite/ChangeLog:

	PR modula2/121629
	* gm2/switches/pathnameroot/pass/switches-pathnameroot-pass.exp: New test.
	* gm2/switches/pathnameroot/pass/test.mod: New test.
	* gm2/switches/pathnameroot/pass/testlib/m2/foo.def: New test.
	* gm2/switches/pathnameroot/pass/testlib/m2/foo.mod: New test.

Signed-off-by: Gaius Mulley <gaiusmod2@gmail.com>

9 files changed, 384 insertions, 94 deletions

diff --git a/gcc/doc/gm2.texi b/gcc/doc/gm2.texi
index 9bd0f0d..4147a287 100644
--- a/gcc/doc/gm2.texi
+++ b/gcc/doc/gm2.texi
@@ -143,11 +143,7 @@ available and access to assembly programming is achieved using the
 same syntax as that used by GCC.
 
 The gm2 driver allows third party libraries to be installed alongside
-gm2 libraries.  For example if the user specifies library @code{foo}
-using @code{-flibs=foo} the driver will check the standard GCC install
-directory for a sub directory @code{foo} containing the library
-contents.  The library module search path is altered accordingly
-for compile and link.
+gm2 libraries.  @xref{Module Search Path}.
 
 @node Development, Features, Why use GNU Modula-2, Overview
 @section How to get source code using git
@@ -229,6 +225,7 @@ such as the AVR and the ARM).
 * Standard procedures::   Permanently accessible base procedures.
 * High procedure function:: Behavior of the high procedure function.
 * Dialect::               GNU Modula-2 supported dialects.
+* Module Search Path::    How to add library modules.
 * Exceptions::            Exception implementation
 * Semantic checking::     How to detect run time problems at compile time.
 * Extensions::            GNU Modula-2 language extensions.
@@ -525,6 +522,15 @@ following include paths.
 for internal use only: used by the driver to copy the user facing @samp{-I}
 option.
 
+@item -fm2-pathname-root=@file{pathroot}
+add search paths derived from the specified @file{pathroot}.
+@xref{Module Search Path} for examples.
+
+@item -fm2-pathname-rootI
+for internal use only: used by the driver to copy every user
+@samp{-fm2-pathname-root=} facing option in order with all other
+@samp{-I} options.
+
 @item -fm2-plugin
 insert plugin to identify run time errors at compile time (default on).
 
@@ -1379,7 +1385,7 @@ Actual parameter | HIGH (a) | a[HIGH (a)] = nul
  str3            | 3        | TRUE
 @end example
 
-@node Dialect, Exceptions, High procedure function, Using
+@node Dialect, Module Search Path, High procedure function, Using
 @section GNU Modula-2 supported dialects
 
 This section describes the dialects understood by GNU Modula-2.
@@ -1444,6 +1450,39 @@ implemented as above, apart from the exception calling in the ISO
 dialect.  Instead of exception handling the results are the same as the
 PIM4 dialect.  This is a temporary implementation situation.
 
+@node Module Search Path, Exceptions, Dialect, Using
+@section Module Search Path
+
+This section describes the default module search path and how this
+might be changed.  By default the compiler will search the current
+directory, site wide modules and lastly gcc version specific modules.
+
+The @samp{-I} option option can be used to introduce new directories
+in the module search path and for convenience the options @samp{-flibs=}
+and @samp{-fm2-pathname-root=} are also provided.
+
+The site wide modules are located at @var{prefix}@file{/include/m2}
+whereas the version specific modules are located in
+@var{libsubdir}@file{/m2}.  Both of these @file{/m2} directories
+are organized such that the non dialect specific modules are at the
+top and dialect specific modules are in subdirectories.
+
+The @samp{-fm2-pathname-root=} option is equivalent to adding a
+@samp{-I} path for every library dialect.  For example if the library
+dialect order is selected by @samp{-flibs=pim,iso,log} and
+@samp{-fm2-pathname-root=foo} is supplied then this is equivalent to
+the following pairs of options:
+
+@example
+-fm2-pathname=m2pim -I@file{foo/m2/m2pim}
+-fm2-pathname=m2iso -I@file{foo/m2/m2iso}
+-fm2-pathname=m2log -I@file{foo/m2/m2log}
+-fm2-pathname=- -I@file{foo/m2}
+@end example
+
+The option @samp{-fsources} will show the source module, path and
+pathname for each module parsed.
+
 @node Exceptions, Semantic checking, Dialect, Using
 @section Exception implementation
 
@@ -2023,7 +2062,7 @@ CONST
 
 VAR
    head: List ;
-@end group   
+@end group
 @end example
 
 @example
@@ -2034,13 +2073,13 @@ VAR
 BEGIN
    p := head^.next ;
    printf ("\nunique data\n");
-   printf ("===========\n");   
+   printf ("===========\n");
    WHILE p # NIL DO
       printf ("%d\n", p^.value);
       p := p^.next
    END
 END Display ;
-@end group   
+@end group
 @end example
 
 @example
@@ -2053,7 +2092,7 @@ BEGIN
       next := NIL
    END
 END Add ;
-@end group   
+@end group
 @end example
 
 @example
@@ -2075,17 +2114,17 @@ EXCEPT
    THEN
       printf ("list was empty, add sentinal\n");
       Add (head, -1) ;
-      RETRY  (* Jump back to the begin statement.  *)      
+      RETRY  (* Jump back to the begin statement.  *)
    ELSIF p^.next = NIL
    THEN
       printf ("growing the list\n");
       Add (p^.next, val) ;
       RETRY  (* Jump back to the begin statement.  *)
    ELSE
-      printf ("should never reach here!\n");   
+      printf ("should never reach here!\n");
    END
 END Unique ;
-@end group   
+@end group
 @end example
 
 @example
@@ -2104,7 +2143,7 @@ BEGIN
    head := NIL ;
    unique
 END lazyunique.
-@end group   
+@end group
 @end example
 
 @example
@@ -2127,7 +2166,7 @@ unique data
 0
 2
 1
-@end group   
+@end group
 @end example
 
 @node Unbounded by reference, Building a shared library, Exception handling, Using
diff --git a/gcc/m2/gm2-compiler/PathName.mod b/gcc/m2/gm2-compiler/PathName.mod
index 6fc7612..0ba9024 100644
--- a/gcc/m2/gm2-compiler/PathName.mod
+++ b/gcc/m2/gm2-compiler/PathName.mod
@@ -1,3 +1,24 @@
+(* M2PathName.mod maintain a dictionary of named paths.
+
+Copyright (C) 2023-2025 Free Software Foundation, Inc.
+Contributed by Gaius Mulley <gaius.mulley@southwales.ac.uk>.
+
+This file is part of GNU Modula-2.
+
+GNU Modula-2 is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3, or (at your option)
+any later version.
+
+GNU Modula-2 is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Modula-2; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  *)
+
 IMPLEMENTATION MODULE PathName ;
 
 FROM Storage IMPORT ALLOCATE, DEALLOCATE ;
diff --git a/gcc/m2/gm2-lang.cc b/gcc/m2/gm2-lang.cc
index 31a2e46..d378d1b 100644
--- a/gcc/m2/gm2-lang.cc
+++ b/gcc/m2/gm2-lang.cc
@@ -51,6 +51,7 @@ static bool iso = false;
 typedef struct named_path_s {
   std::vector<const char*>path;
   const char *name;
+  bool lib_root;
 } named_path;
 
 
@@ -372,6 +373,7 @@ push_back_Ipath (const char *arg)
       named_path np;
       np.path.push_back (arg);
       np.name = xstrdup (M2Options_GetM2PathName ());
+      np.lib_root = false;
       Ipaths.push_back (np);
     }
   else
@@ -384,11 +386,205 @@ push_back_Ipath (const char *arg)
 	  named_path np;
 	  np.path.push_back (arg);
 	  np.name = xstrdup (M2Options_GetM2PathName ());
+	  np.lib_root = false;
 	  Ipaths.push_back (np);
 	}
     }
 }
 
+/* push_back_lib_root pushes a lib_root onto the Ipaths vector.
+   The ordering of the -fm2_add_lib_root=, -I and named paths
+   must be preserved.  */
+
+static void
+push_back_lib_root (const char *arg)
+{
+  named_path np;
+  np.name = arg;
+  np.lib_root = true;
+  Ipaths.push_back (np);
+}
+
+/* get_dir_sep_size return the length of the DIR_SEPARATOR string.  */
+
+static size_t
+get_dir_sep_size (void)
+{
+  const char dir_sep[] = {DIR_SEPARATOR, (char)0};
+  size_t dir_sep_size = strlen (dir_sep);
+  return dir_sep_size;
+}
+
+/* add_path_component strcats src into dest and adds a directory seperator
+   if necessary.  */
+
+static void
+add_path_component (char *dest, const char *src)
+{
+  size_t len = strlen (dest);
+  const char dir_sep[] = {DIR_SEPARATOR, (char)0};
+  size_t dir_sep_size = strlen (dir_sep);
+
+  if (len > 0)
+    {
+      /* Only add a seperator if dest is not empty and does not end
+	 with a seperator.  */
+      if (len >= dir_sep_size
+	  && (strcmp (&dest[len-dir_sep_size], dir_sep) != 0))
+	strcat (dest, dir_sep);
+    }
+  strcat (dest, src);
+}
+
+/* This prefixes LIBNAME with the current compiler prefix (if it has been
+   relocated) or the LIBSUBDIR, if not.  */
+
+static void
+add_one_import_path (const char *libpath, const char *libname)
+{
+  size_t dir_sep_size = get_dir_sep_size ();
+  size_t mlib_len = 0;
+
+  if (imultilib)
+    {
+      mlib_len = strlen (imultilib);
+      mlib_len += dir_sep_size;
+    }
+
+  char *lib = (char *)alloca (strlen (libpath) + dir_sep_size
+			      + strlen ("m2") + dir_sep_size
+			      + strlen (libname) + 1
+			      + mlib_len + 1);
+  strcpy (lib, libpath);
+  if (imultilib)
+    add_path_component (lib, imultilib);
+  add_path_component (lib, "m2");
+  add_path_component (lib, libname);
+  M2Options_SetM2PathName (libname);
+  M2Options_SetSearchPath (lib);
+}
+
+/* add_non_dialect_specific_path add non dialect specific includes
+   given a base libpath.  */
+
+static void
+add_non_dialect_specific_path (const char *libpath)
+{
+  char *incpath = (char *)alloca (strlen (libpath)
+				  + strlen ("m2")
+				  + get_dir_sep_size ()
+				  + 1);
+  strcpy (incpath, libpath);
+  add_path_component (incpath, "m2");
+  M2Options_SetM2PathName ("");   /* No pathname for non dialect specific libs.  */
+  M2Options_SetSearchPath (incpath);
+}
+
+/* For each comma-separated standard library name in LIBLIST, add the
+   corresponding include path.  */
+
+static void
+foreach_lib_gen_import_path (const char *liblist, const char *libpath)
+{
+  while (*liblist != 0 && *liblist != '-')
+    {
+      const char *comma = strstr (liblist, ",");
+      size_t len;
+      if (comma)
+	len = comma - liblist;
+      else
+	len = strlen (liblist);
+      char *libname = (char *) alloca (len+1);
+      strncpy (libname, liblist, len);
+      libname[len] = 0;
+      add_one_import_path (libpath, libname);
+      liblist += len;
+      if (*liblist == ',')
+	liblist++;
+    }
+  add_non_dialect_specific_path (libpath);
+}
+
+/* get_module_source_dir return the libpath/{multilib/} as a malloc'd
+   string.  */
+
+static const char *
+get_module_source_dir (void)
+{
+  const char *libpath = iprefix ? iprefix : LIBSUBDIR;
+  const char dir_sep[] = {DIR_SEPARATOR, (char)0};
+  size_t dir_sep_size = strlen (dir_sep);
+  unsigned int mlib_len = 0;
+
+  if (imultilib)
+    {
+      mlib_len = strlen (imultilib);
+      mlib_len += strlen (dir_sep);
+    }
+  char *lib = (char *) xmalloc (strlen (libpath)
+				+ dir_sep_size
+				+ mlib_len + 1);
+  strcpy (lib, libpath);
+  /* iprefix has a trailing dir separator, LIBSUBDIR does not.  */
+  if (!iprefix)
+    strcat (lib, dir_sep);
+
+  if (imultilib)
+    {
+      strcat (lib, imultilib);
+      strcat (lib, dir_sep);
+    }
+  return lib;
+}
+
+/* add_default_include_paths add include paths for site wide definition modules
+   and also gcc version specific definition modules.  */
+
+static void
+add_default_include_paths (const char *flibs)
+{
+  /* Add the site wide include path.  */
+  foreach_lib_gen_import_path (flibs, PREFIX_INCLUDE_DIR);
+  /* Add the gcc version specific include path.  */
+  foreach_lib_gen_import_path (flibs,
+			       get_module_source_dir ());
+}
+
+/* assign_flibs assign flibs to a default providing that allow_libraries
+   is true and flibs has not been set.  */
+
+static void
+assign_flibs (void)
+{
+  if (allow_libraries && (flibs == NULL))
+    {
+      if (iso)
+	flibs = "m2iso,m2cor,m2pim,m2log";
+      else
+	flibs = "m2pim,m2iso,m2cor,m2log";
+    }
+}
+
+/* m2_pathname_root creates a new set of include paths for the
+   subdirectory m2 inside libroot.  The ordering of the paths
+   follows the dialect library order.  */
+
+static void
+m2_pathname_root (const char *libroot)
+{
+  const char *copy_flibs = flibs;
+
+  if (copy_flibs == NULL)
+    {
+      if (iso)
+	copy_flibs = "m2iso,m2cor,m2pim,m2log";
+      else
+	copy_flibs = "m2pim,m2iso,m2cor,m2log";
+    }
+  foreach_lib_gen_import_path (copy_flibs, libroot);
+}
+
+
 /* Handle gm2 specific options.  Return 0 if we didn't do anything.  */
 
 bool
@@ -435,6 +631,9 @@ gm2_langhook_handle_option (
     case OPT_fpositive_mod_floor_div:
       M2Options_SetPositiveModFloor (value);
       return 1;
+    case OPT_fm2_pathname_rootI_:
+      push_back_lib_root (arg);
+      return 1;
     case OPT_flibs_:
       allow_libraries = value;
       flibs = arg;
@@ -710,66 +909,6 @@ gm2_langhook_handle_option (
   return 0;
 }
 
-/* This prefixes LIBNAME with the current compiler prefix (if it has been
-   relocated) or the LIBSUBDIR, if not.  */
-static void
-add_one_import_path (const char *libname)
-{
-  const char *libpath = iprefix ? iprefix : LIBSUBDIR;
-  const char dir_sep[] = {DIR_SEPARATOR, (char)0};
-  size_t dir_sep_size = strlen (dir_sep);
-  unsigned int mlib_len = 0;
-
-  if (imultilib)
-    {
-      mlib_len = strlen (imultilib);
-      mlib_len += strlen (dir_sep);
-    }
-
-  char *lib = (char *)alloca (strlen (libpath) + dir_sep_size
-			      + strlen ("m2") + dir_sep_size
-			      + strlen (libname) + 1
-			      + mlib_len + 1);
-  strcpy (lib, libpath);
-  /* iprefix has a trailing dir separator, LIBSUBDIR does not.  */
-  if (!iprefix)
-    strcat (lib, dir_sep);
-
-  if (imultilib)
-    {
-      strcat (lib, imultilib);
-      strcat (lib, dir_sep);
-    }
-  strcat (lib, "m2");
-  strcat (lib, dir_sep);
-  strcat (lib, libname);
-  M2Options_SetM2PathName (libname);
-  M2Options_SetSearchPath (lib);
-}
-
-/* For each comma-separated standard library name in LIBLIST, add the
-   corresponding include path.  */
-static void
-add_m2_import_paths (const char *liblist)
-{
-  while (*liblist != 0 && *liblist != '-')
-    {
-      const char *comma = strstr (liblist, ",");
-      size_t len;
-      if (comma)
-	len = comma - liblist;
-      else
-	len = strlen (liblist);
-      char *libname = (char *) alloca (len+1);
-      strncpy (libname, liblist, len);
-      libname[len] = 0;
-      add_one_import_path (libname);
-      liblist += len;
-      if (*liblist == ',')
-	liblist++;
-    }
-}
-
 /* Run after parsing options.  */
 
 static bool
@@ -784,16 +923,7 @@ gm2_langhook_post_options (const char **pfilename)
   /* Add the include paths as per the libraries specified.
      NOTE: This assumes that the driver has validated the input and makes
      no attempt to be defensive of nonsense input in flibs=.  */
-  if (allow_libraries)
-    {
-      if (!flibs)
-	{
-	  if (iso)
-	    flibs = "m2iso,m2cor,m2pim,m2log";
-	  else
-	    flibs = "m2pim,m2iso,m2cor,m2log";
-	}
-    }
+  assign_flibs ();
 
   /* Add search paths.
      We are not handling all of the cases yet (e.g idirafter).
@@ -807,9 +937,14 @@ gm2_langhook_post_options (const char **pfilename)
   iquote.clear();
   for (auto np : Ipaths)
     {
-      M2Options_SetM2PathName (np.name);
-      for (auto *s : np.path)
-	M2Options_SetSearchPath (s);
+      if (np.lib_root)
+	foreach_lib_gen_import_path (flibs, np.name);
+      else
+	{
+	  M2Options_SetM2PathName (np.name);
+	  for (auto *s : np.path)
+	    M2Options_SetSearchPath (s);
+	}
     }
   Ipaths.clear();
   for (auto *s : isystem)
@@ -818,7 +953,7 @@ gm2_langhook_post_options (const char **pfilename)
   /* FIXME: this is not a good way to suppress the addition of the import
      paths.  */
   if (allow_libraries)
-    add_m2_import_paths (flibs);
+    add_default_include_paths (flibs);
 
   /* Returning false means that the backend should be used.  */
   return M2Options_GetPPOnly ();
diff --git a/gcc/m2/gm2spec.cc b/gcc/m2/gm2spec.cc
index 868e5c5..18d9ce7 100644
--- a/gcc/m2/gm2spec.cc
+++ b/gcc/m2/gm2spec.cc
@@ -158,10 +158,12 @@ static const char *m2_path_name = "";
 typedef struct named_path_s {
   std::vector<const char*>path;
   const char *name;
+  bool lib_root;
 } named_path;
 
 static std::vector<named_path>Ipaths;
 
+/* push_back_Ipath pushes a named path to the Ipaths global variable.  */
 
 static void
 push_back_Ipath (const char *arg)
@@ -171,6 +173,7 @@ push_back_Ipath (const char *arg)
       named_path np;
       np.path.push_back (arg);
       np.name = m2_path_name;
+      np.lib_root = false;
       Ipaths.push_back (np);
     }
   else
@@ -183,11 +186,25 @@ push_back_Ipath (const char *arg)
 	  named_path np;
 	  np.path.push_back (arg);
 	  np.name = m2_path_name;
+	  np.lib_root = false;
 	  Ipaths.push_back (np);
 	}
     }
 }
 
+/* push_back_lib_root pushes a lib_root onto the Ipaths vector.
+   The ordering of the -fm2_add_lib_root=, -I and named paths
+   must be preserved.  */
+
+static void
+push_back_lib_root (const char *arg)
+{
+  named_path np;
+  np.name = arg;
+  np.lib_root = true;
+  Ipaths.push_back (np);
+}
+
 /* Return whether strings S1 and S2 are both NULL or both the same
    string.  */
 
@@ -379,15 +396,18 @@ convert_abbreviations (const char *libraries)
   return full_libraries;
 }
 
-/* add_m2_I_path appends -fm2-pathname and -fm2-pathnameI options to
-   the command line which are contructed in the saved Ipaths.  */
+/* add_m2_I_path appends -fm2-pathname, -fm2-pathnameI and -fm2-add-lib-root
+   options to the command line which are contructed in the saved Ipaths.
+   The order of these options must be maintained.  */
 
 static void
 add_m2_I_path (void)
 {
   for (auto np : Ipaths)
     {
-      if (strcmp (np.name, "") == 0)
+      if (np.lib_root)
+	append_option (OPT_fm2_pathname_rootI_, safe_strdup (np.name), 1);
+      else if (strcmp (np.name, "") == 0)
 	append_option (OPT_fm2_pathname_, safe_strdup ("-"), 1);
       else
 	append_option (OPT_fm2_pathname_, safe_strdup (np.name), 1);
@@ -576,6 +596,10 @@ lang_specific_driver (struct cl_decoded_option **in_decoded_options,
 	  args[i] |= SKIPOPT; /* We will add the option if it is needed.  */
 	  m2_path_name = decoded_options[i].arg;
 	  break;
+	case OPT_fm2_pathname_root_:
+	  args[i] |= SKIPOPT; /* We will add the option if it is needed.  */
+	  push_back_lib_root (decoded_options[i].arg);
+	  break;
 	case OPT__help:
 	case OPT__help_:
 	  /* Let gcc.cc handle this, as it has a really
@@ -739,7 +763,6 @@ lang_specific_driver (struct cl_decoded_option **in_decoded_options,
 	       "-fgen-module-list=", "-fuse-list=");
     }
 
-
   /* There's no point adding -shared-libgcc if we don't have a shared
      libgcc.  */
 #ifndef ENABLE_SHARED_LIBGCC
diff --git a/gcc/m2/lang.opt b/gcc/m2/lang.opt
index 48c2380..2aea4cc 100644
--- a/gcc/m2/lang.opt
+++ b/gcc/m2/lang.opt
@@ -172,7 +172,15 @@ specify the module mangled prefix name for all modules in the following include
 
 fm2-pathnameI
 Modula-2 Joined
-; For internal use only: used by the driver to copy the user facing -I option
+; For internal use only: used by the driver to copy the user facing -I option in order
+
+fm2-pathname-root=
+Modula-2 Joined
+add include paths for all the library names in -flibs= to this directory root
+
+fm2-pathname-rootI=
+Modula-2 Joined
+; For internal use only: used by the driver to copy the user facing -I option in order
 
 fm2-plugin
 Modula-2
diff --git a/gcc/testsuite/gm2/switches/pathnameroot/pass/switches-pathnameroot-pass.exp b/gcc/testsuite/gm2/switches/pathnameroot/pass/switches-pathnameroot-pass.exp
new file mode 100755
index 0000000..d2f4d87
--- /dev/null
+++ b/gcc/testsuite/gm2/switches/pathnameroot/pass/switches-pathnameroot-pass.exp
@@ -0,0 +1,48 @@
+# Expect driver script for GCC Regression Tests
+# Copyright (C) 2025 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with GCC; see the file COPYING3.  If not see
+# <http://www.gnu.org/licenses/>.
+
+# This file was written by Gaius Mulley (gaius.mulley@southwales.ac.uk)
+# for GNU Modula-2.
+
+load_lib target-supports.exp
+
+global TESTING_IN_BUILD_TREE
+global ENABLE_PLUGIN
+
+# The plugin testcases currently only work when the build tree is available.
+# Also check whether the host supports plugins.
+if { ![info exists TESTING_IN_BUILD_TREE] || ![info exists ENABLE_PLUGIN] } {
+    return
+}
+
+if $tracelevel then {
+    strace $tracelevel
+}
+
+# load support procs
+load_lib gm2-torture.exp
+
+gm2_init_pim "${srcdir}/gm2/switches/pathnameroot/pass" -fm2-pathname-root="${srcdir}/gm2/switches/pathnameroot/pass/testlib"
+
+foreach testcase [lsort [glob -nocomplain $srcdir/$subdir/*.mod]] {
+    # If we're only testing specific files and this isn't one of them, skip it.
+    if ![runtest_file_p $runtests $testcase] then {
+	continue
+    }
+
+    gm2-torture-fail $testcase
+}
diff --git a/gcc/testsuite/gm2/switches/pathnameroot/pass/test.mod b/gcc/testsuite/gm2/switches/pathnameroot/pass/test.mod
new file mode 100644
index 0000000..0f9cd6f
--- /dev/null
+++ b/gcc/testsuite/gm2/switches/pathnameroot/pass/test.mod
@@ -0,0 +1,6 @@
+MODULE test ;
+
+FROM foo IMPORT SomeValue ;
+
+BEGIN
+END test.
diff --git a/gcc/testsuite/gm2/switches/pathnameroot/pass/testlib/m2/foo.def b/gcc/testsuite/gm2/switches/pathnameroot/pass/testlib/m2/foo.def
new file mode 100644
index 0000000..9fa4973
--- /dev/null
+++ b/gcc/testsuite/gm2/switches/pathnameroot/pass/testlib/m2/foo.def
@@ -0,0 +1,7 @@
+DEFINITION MODULE foo ;
+
+CONST
+   SomeValue = 123 ;
+
+
+END foo.
diff --git a/gcc/testsuite/gm2/switches/pathnameroot/pass/testlib/m2/foo.mod b/gcc/testsuite/gm2/switches/pathnameroot/pass/testlib/m2/foo.mod
new file mode 100644
index 0000000..fcbcf1e
--- /dev/null
+++ b/gcc/testsuite/gm2/switches/pathnameroot/pass/testlib/m2/foo.mod
@@ -0,0 +1,3 @@
+IMPLEMENTATION MODULE foo ;
+
+END foo.