c++: Fix OpenMP support with C++20 modules [PR119864]

In r15-2799-gf1bfba3a9b3f31, a new kind of global constructor was added.
Unfortunately this broke C++20 modules, as both the host and target
constructors were given the same mangled name.  This patch ensures that
only the host constructor gets the module name mangling for now, and
stops forcing the creation of the target constructor even when no such
initialization is required.

	PR c++/119864

gcc/cp/ChangeLog:

	* decl2.cc (start_objects): Only use module initialized for
	host.
	(c_parse_final_cleanups): Don't always create an OMP offload
	init function in modules.

gcc/testsuite/ChangeLog:

	* g++.dg/modules/openmp-1.C: New test.

Signed-off-by: Nathaniel Shead <nathanieloshead@gmail.com>
Reviewed-by: Jason Merrill <jason@redhat.com>
(cherry picked from commit 79b7e37ea3fbbc43958190f69f6da3be3d809c9c)

diff --git a/gcc/cp/decl2.cc b/gcc/cp/decl2.cc
index 21156f1dd3b7a6ba40cc389a61229b4c1d25931d..a137e88eeda635c6558f9a4947de894f27aae067 100644 (file)
--- a/gcc/cp/decl2.cc
+++ b/gcc/cp/decl2.cc
@@ -4184,7 +4184,11 @@ start_objects (bool initp, unsigned priority, bool has_body,
               bool omp_target = false)
 {
   bool default_init = initp && priority == DEFAULT_INIT_PRIORITY;
-  bool is_module_init = default_init && module_global_init_needed ();
+  /* FIXME: We may eventually want to treat OpenMP offload initializers
+     in modules specially as well.  */
+  bool is_module_init = (default_init
+                        && !omp_target
+                        && module_global_init_needed ());
   tree name = NULL_TREE;
 
   if (is_module_init)
@@ -5876,12 +5880,8 @@ c_parse_final_cleanups (void)
       if (static_init_fini_fns[true]->get_or_insert (DEFAULT_INIT_PRIORITY))
        has_module_inits = true;
 
-      if (flag_openmp)
-       {
-         if (!static_init_fini_fns[2 + true])
-           static_init_fini_fns[2 + true] = priority_map_t::create_ggc ();
-         static_init_fini_fns[2 + true]->get_or_insert (DEFAULT_INIT_PRIORITY);
-       }
+      /* FIXME: We need to work out what static constructors on OpenMP offload
+        target in modules will look like.  */
     }
 
   /* Generate initialization and destruction functions for all

diff --git a/gcc/testsuite/g++.dg/modules/openmp-1.C b/gcc/testsuite/g++.dg/modules/openmp-1.C
new file mode 100644 (file)
index 0000000..b5a30ad
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/openmp-1.C
@@ -0,0 +1,9 @@
+// PR c++/119864
+// { dg-do assemble }
+// { dg-additional-options "-fmodules -fopenmp" }
+// { dg-require-effective-target "fopenmp" }
+
+export module M;
+
+int foo();
+int x = foo();