Incremental LTO linking part 3: lto-wrapper support

[Jan Hubicka]

Hi,
this patch makes lto-wrapper to look for -flinker-output=rel and in this
case confiugre lto1 in non-WHOPR mode + disable section renaming.

Bootstrapped/regtested x86_64-linux with rest of incremental link patchset.
OK?

        * lto-wrapper.c (debug_objcopy): Add rename parameter; pass
        it down to simple_object_copy_lto_debug_sections.
        (run_gcc): Determine incremental LTO link time and configure
        lto1 into non-wpa mode, disable renaming of debug sections.

Index: lto-wrapper.c
===================================================================
--- lto-wrapper.c       (revision 260042)
+++ lto-wrapper.c       (working copy)
@@ -966,7 +966,7 @@
    is returned.  Return NULL on error.  */
 
 const char *
-debug_objcopy (const char *infile)
+debug_objcopy (const char *infile, bool rename)
 {
   const char *outfile;
   const char *errmsg;
@@ -1008,7 +1008,7 @@
     }
 
   outfile = make_temp_file ("debugobjtem");
-  errmsg = simple_object_copy_lto_debug_sections (inobj, outfile, &err);
+  errmsg = simple_object_copy_lto_debug_sections (inobj, outfile, &err, 
rename);
   if (errmsg)
     {
       unlink_if_ordinary (outfile);
@@ -1056,6 +1056,7 @@
   bool have_offload = false;
   unsigned lto_argc = 0, ltoobj_argc = 0;
   char **lto_argv, **ltoobj_argv;
+  bool linker_output_rel = false;
   bool skip_debug = false;
   unsigned n_debugobj;
 
@@ -1108,9 +1109,12 @@
          file_offset = (off_t) loffset;
        }
       fd = open (filename, O_RDONLY | O_BINARY);
+      /* Linker plugin passes -fresolution and -flinker-output options.  */
       if (fd == -1)
        {
          lto_argv[lto_argc++] = argv[i];
+         if (strcmp (argv[i], "-flinker-output=rel") == 0)
+           linker_output_rel = true;
          continue;
        }
 
@@ -1175,6 +1179,11 @@
          lto_mode = LTO_MODE_WHOPR;
          break;
 
+       case OPT_flinker_output_:
+         linker_output_rel = !strcmp (option->arg, "rel");
+         break;
+
+
        default:
          break;
        }
@@ -1191,6 +1200,9 @@
       fputc ('\n', stderr);
     }
 
+  if (linker_output_rel)
+    no_partition = true;
+
   if (no_partition)
     {
       lto_mode = LTO_MODE_LTO;
@@ -1435,7 +1447,7 @@
     for (i = 0; i < ltoobj_argc; ++i)
       {
        const char *tem;
-       if ((tem = debug_objcopy (ltoobj_argv[i])))
+       if ((tem = debug_objcopy (ltoobj_argv[i], !linker_output_rel)))
          {
            obstack_ptr_grow (&argv_obstack, tem);
            n_debugobj++;