openmp: Add crtoffloadtableS.o and use it [PR117851]

Unlike crtoffload{begin,end}.o which just define some symbols at the start/end
of the various .gnu.offload* sections, crtoffloadtable.o contains
const void *const __OFFLOAD_TABLE__[]
  __attribute__ ((__visibility__ ("hidden"))) =
{
  &__offload_func_table, &__offload_funcs_end,
  &__offload_var_table, &__offload_vars_end,
  &__offload_ind_func_table, &__offload_ind_funcs_end,
};
The problem is that linking this into PIEs or shared libraries doesn't
work when it is compiled without -fpic/-fpie - __OFFLOAD_TABLE__ for non-PIC
code is put into .rodata section, but it really needs relocations, so for
PIC it should go into .data.rel.ro/.data.rel.ro.local.
As I think we don't want .data.rel.ro section in non-PIE binaries, this patch
follows the path of e.g. crtbegin.o vs. crtbeginS.o and adds crtoffloadtableS.o
next to crtoffloadtable.o, where crtoffloadtableS.o is compiled with -fpic.

2024-11-30  Jakub Jelinek  <jakub@redhat.com>

	PR libgomp/117851
gcc/
	* lto-wrapper.cc (find_crtoffloadtable): Add PIE_OR_SHARED argument,
	search for crtoffloadtableS.o rather than crtoffloadtable.o if
	true.
	(run_gcc): Add pie_or_shared variable.  If OPT_pie or OPT_shared or
	OPT_static_pie is seen, set pie_or_shared to true, if OPT_no_pie is
	seen, set pie_or_shared to false.  Pass it to find_crtoffloadtable.
libgcc/
	* configure.ac (extra_parts): Add crtoffloadtableS.o.
	* Makefile.in (crtoffloadtableS$(objext)): New goal.
	* configure: Regenerated.

1 files changed, 23 insertions, 4 deletions

diff --git a/gcc/lto-wrapper.cc b/gcc/lto-wrapper.cc
index 700da6c..661ba3c 100644
--- a/gcc/lto-wrapper.cc
+++ b/gcc/lto-wrapper.cc
@@ -1092,13 +1092,16 @@ copy_file (const char *dest, const char *src)
    the copy to the linker.  */
 
 static void
-find_crtoffloadtable (int save_temps, const char *dumppfx)
+find_crtoffloadtable (int save_temps, bool pie_or_shared, const char *dumppfx)
 {
   char **paths = NULL;
   const char *library_path = getenv ("LIBRARY_PATH");
   if (!library_path)
     return;
-  unsigned n_paths = parse_env_var (library_path, &paths, "/crtoffloadtable.o");
+  unsigned n_paths = parse_env_var (library_path, &paths,
+				    pie_or_shared
+				    ? "/crtoffloadtableS.o"
+				    : "/crtoffloadtable.o");
 
   unsigned i;
   for (i = 0; i < n_paths; i++)
@@ -1117,7 +1120,8 @@ find_crtoffloadtable (int save_temps, const char *dumppfx)
       }
   if (i == n_paths)
     fatal_error (input_location,
-		 "installation error, cannot find %<crtoffloadtable.o%>");
+		 "installation error, cannot find %<crtoffloadtable%s.o%>",
+		 pie_or_shared ? "S" : "");
 
   free_array_of_ptrs ((void **) paths, n_paths);
 }
@@ -1423,6 +1427,11 @@ run_gcc (unsigned argc, char *argv[])
   char **lto_argv, **ltoobj_argv;
   bool linker_output_rel = false;
   bool skip_debug = false;
+#ifdef ENABLE_DEFAULT_PIE
+  bool pie_or_shared = true;
+#else
+  bool pie_or_shared = false;
+#endif
   const char *incoming_dumppfx = dumppfx = NULL;
   static char current_dir[] = { '.', DIR_SEPARATOR, '\0' };
 
@@ -1594,6 +1603,16 @@ run_gcc (unsigned argc, char *argv[])
 	  global_dc->set_show_highlight_colors (option->value);
 	  break;
 
+	case OPT_pie:
+	case OPT_shared:
+	case OPT_static_pie:
+	  pie_or_shared = true;
+	  break;
+
+	case OPT_no_pie:
+	  pie_or_shared = false;
+	  break;
+
 	default:
 	  break;
 	}
@@ -1802,7 +1821,7 @@ cont1:
 
       if (offload_names)
 	{
-	  find_crtoffloadtable (save_temps, dumppfx);
+	  find_crtoffloadtable (save_temps, pie_or_shared, dumppfx);
 	  for (i = 0; offload_names[i]; i++)
 	    printf ("%s\n", offload_names[i]);
 	  free_array_of_ptrs ((void **) offload_names, i);