xref: /netbsd-src/external/gpl3/gcc.old/dist/gcc/config/i386/intelmic-mkoffload.c (revision 8feb0f0b7eaff0608f8350bbfa3098827b4bb91b)
1 /* Offload image generation tool for Intel MIC devices.
2 
3    Copyright (C) 2014-2020 Free Software Foundation, Inc.
4 
5    Contributed by Ilya Verbin <ilya.verbin@intel.com>.
6 
7    This file is part of GCC.
8 
9    GCC is free software; you can redistribute it and/or modify
10    it under the terms of the GNU General Public License as published by
11    the Free Software Foundation; either version 3, or (at your option)
12    any later version.
13 
14    GCC is distributed in the hope that it will be useful,
15    but WITHOUT ANY WARRANTY; without even the implied warranty of
16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17    GNU General Public License for more details.
18 
19    You should have received a copy of the GNU General Public License
20    along with GCC; see the file COPYING3.  If not see
21    <http://www.gnu.org/licenses/>.  */
22 
23 #define IN_TARGET_CODE 1
24 
25 #include "config.h"
26 #include <libgen.h>
27 #include "system.h"
28 #include "coretypes.h"
29 #include "obstack.h"
30 #include "intl.h"
31 #include "diagnostic.h"
32 #include "collect-utils.h"
33 #include "intelmic-offload.h"
34 
35 const char tool_name[] = "intelmic mkoffload";
36 
37 const char image_section_name[] = ".gnu.offload_images";
38 const char *symbols[3] = { "__offload_image_intelmic_start",
39 			   "__offload_image_intelmic_end",
40 			   "__offload_image_intelmic_size" };
41 const char *out_obj_filename = NULL;
42 
43 int num_temps = 0;
44 const int MAX_NUM_TEMPS = 10;
45 const char *temp_files[MAX_NUM_TEMPS];
46 
47 enum offload_abi offload_abi = OFFLOAD_ABI_UNSET;
48 
49 /* Delete tempfiles and exit function.  */
50 
51 void
tool_cleanup(bool from_signal ATTRIBUTE_UNUSED)52 tool_cleanup (bool from_signal ATTRIBUTE_UNUSED)
53 {
54   for (int i = 0; i < num_temps; i++)
55     maybe_unlink (temp_files[i]);
56 }
57 
58 static void
mkoffload_cleanup(void)59 mkoffload_cleanup (void)
60 {
61   tool_cleanup (false);
62 }
63 
64 /* Unlink FILE unless requested otherwise.  */
65 
66 void
maybe_unlink(const char * file)67 maybe_unlink (const char *file)
68 {
69   if (!save_temps)
70     {
71       if (unlink_if_ordinary (file)
72 	  && errno != ENOENT)
73 	fatal_error (input_location, "deleting file %s: %m", file);
74     }
75   else if (verbose)
76     fprintf (stderr, "[Leaving %s]\n", file);
77 }
78 
79 /* Add or change the value of an environment variable, outputting the
80    change to standard error if in verbose mode.  */
81 static void
xputenv(const char * string)82 xputenv (const char *string)
83 {
84   if (verbose)
85     fprintf (stderr, "%s\n", string);
86   putenv (CONST_CAST (char *, string));
87 }
88 
89 /* Parse STR, saving found tokens into PVALUES and return their number.
90    Tokens are assumed to be delimited by ':'.  */
91 static unsigned
parse_env_var(const char * str,char *** pvalues)92 parse_env_var (const char *str, char ***pvalues)
93 {
94   const char *curval, *nextval;
95   char **values;
96   unsigned num = 1, i;
97 
98   curval = strchr (str, ':');
99   while (curval)
100     {
101       num++;
102       curval = strchr (curval + 1, ':');
103     }
104 
105   values = (char **) xmalloc (num * sizeof (char *));
106   curval = str;
107   nextval = strchr (curval, ':');
108   if (nextval == NULL)
109     nextval = strchr (curval, '\0');
110 
111   for (i = 0; i < num; i++)
112     {
113       int l = nextval - curval;
114       values[i] = (char *) xmalloc (l + 1);
115       memcpy (values[i], curval, l);
116       values[i][l] = 0;
117       curval = nextval + 1;
118       nextval = strchr (curval, ':');
119       if (nextval == NULL)
120 	nextval = strchr (curval, '\0');
121     }
122   *pvalues = values;
123   return num;
124 }
125 
126 /* Auxiliary function that frees elements of PTR and PTR itself.
127    N is number of elements to be freed.  If PTR is NULL, nothing is freed.
128    If an element is NULL, subsequent elements are not freed.  */
129 static void
free_array_of_ptrs(void ** ptr,unsigned n)130 free_array_of_ptrs (void **ptr, unsigned n)
131 {
132   unsigned i;
133   if (!ptr)
134     return;
135   for (i = 0; i < n; i++)
136     {
137       if (!ptr[i])
138 	break;
139       free (ptr[i]);
140     }
141   free (ptr);
142   return;
143 }
144 
145 /* Check whether NAME can be accessed in MODE.  This is like access,
146    except that it never considers directories to be executable.  */
147 static int
access_check(const char * name,int mode)148 access_check (const char *name, int mode)
149 {
150   if (mode == X_OK)
151     {
152       struct stat st;
153 
154       if (stat (name, &st) < 0 || S_ISDIR (st.st_mode))
155 	return -1;
156     }
157 
158   return access (name, mode);
159 }
160 
161 /* Find target compiler using a path from COLLECT_GCC or COMPILER_PATH.  */
162 static char *
find_target_compiler(const char * name)163 find_target_compiler (const char *name)
164 {
165   bool found = false;
166   char **paths = NULL;
167   unsigned n_paths, i;
168   char *target_compiler;
169   const char *collect_gcc = getenv ("COLLECT_GCC");
170   const char *gcc_path = dirname (ASTRDUP (collect_gcc));
171   const char *gcc_exec = basename (ASTRDUP (collect_gcc));
172 
173   if (strcmp (gcc_exec, collect_gcc) == 0)
174     {
175       /* collect_gcc has no path, so it was found in PATH.  Make sure we also
176 	 find accel-gcc in PATH.  */
177       target_compiler = XDUPVEC (char, name, strlen (name) + 1);
178       found = true;
179       goto out;
180     }
181 
182   target_compiler = concat (gcc_path, "/", name, NULL);
183   if (access_check (target_compiler, X_OK) == 0)
184     {
185       found = true;
186       goto out;
187     }
188 
189   n_paths = parse_env_var (getenv ("COMPILER_PATH"), &paths);
190   for (i = 0; i < n_paths; i++)
191     {
192       size_t len = strlen (paths[i]) + 1 + strlen (name) + 1;
193       target_compiler = XRESIZEVEC (char, target_compiler, len);
194       sprintf (target_compiler, "%s/%s", paths[i], name);
195       if (access_check (target_compiler, X_OK) == 0)
196 	{
197 	  found = true;
198 	  break;
199 	}
200     }
201 
202 out:
203   free_array_of_ptrs ((void **) paths, n_paths);
204   return found ? target_compiler : NULL;
205 }
206 
207 static void
compile_for_target(struct obstack * argv_obstack)208 compile_for_target (struct obstack *argv_obstack)
209 {
210   switch (offload_abi)
211     {
212     case OFFLOAD_ABI_LP64:
213       obstack_ptr_grow (argv_obstack, "-m64");
214       break;
215     case OFFLOAD_ABI_ILP32:
216       obstack_ptr_grow (argv_obstack, "-m32");
217       break;
218     default:
219       gcc_unreachable ();
220     }
221   obstack_ptr_grow (argv_obstack, NULL);
222   char **argv = XOBFINISH (argv_obstack, char **);
223 
224   /* Save environment variables.  */
225   const char *epath = getenv ("GCC_EXEC_PREFIX");
226   const char *cpath = getenv ("COMPILER_PATH");
227   const char *lpath = getenv ("LIBRARY_PATH");
228   const char *rpath = getenv ("LD_RUN_PATH");
229   unsetenv ("GCC_EXEC_PREFIX");
230   unsetenv ("COMPILER_PATH");
231   unsetenv ("LIBRARY_PATH");
232   unsetenv ("LD_RUN_PATH");
233 
234   fork_execute (argv[0], argv, false);
235   obstack_free (argv_obstack, NULL);
236 
237   /* Restore environment variables.  */
238   xputenv (concat ("GCC_EXEC_PREFIX=", epath, NULL));
239   xputenv (concat ("COMPILER_PATH=", cpath, NULL));
240   xputenv (concat ("LIBRARY_PATH=", lpath, NULL));
241   xputenv (concat ("LD_RUN_PATH=", rpath, NULL));
242 }
243 
244 /* Generates object file with the descriptor for the target library.  */
245 static const char *
generate_target_descr_file(const char * target_compiler)246 generate_target_descr_file (const char *target_compiler)
247 {
248   const char *src_filename = make_temp_file ("_target_descr.c");
249   const char *obj_filename = make_temp_file ("_target_descr.o");
250   temp_files[num_temps++] = src_filename;
251   temp_files[num_temps++] = obj_filename;
252   FILE *src_file = fopen (src_filename, "w");
253 
254   if (!src_file)
255     fatal_error (input_location, "cannot open '%s'", src_filename);
256 
257   fprintf (src_file,
258 	   "extern const void *const __offload_funcs_end[];\n"
259 	   "extern const void *const __offload_vars_end[];\n\n"
260 
261 	   "const void *const __offload_func_table[0]\n"
262 	   "__attribute__ ((__used__, visibility (\"hidden\"),\n"
263 	   "section (\".gnu.offload_funcs\"))) = { };\n\n"
264 
265 	   "const void *const __offload_var_table[0]\n"
266 	   "__attribute__ ((__used__, visibility (\"hidden\"),\n"
267 	   "section (\".gnu.offload_vars\"))) = { };\n\n"
268 
269 	   "const void *const __OFFLOAD_TARGET_TABLE__[]\n"
270 	   "__attribute__ ((__used__, visibility (\"hidden\"))) = {\n"
271 	   "  &__offload_func_table, &__offload_funcs_end,\n"
272 	   "  &__offload_var_table, &__offload_vars_end\n"
273 	   "};\n\n");
274 
275   fprintf (src_file,
276 	   "#ifdef __cplusplus\n"
277 	   "extern \"C\"\n"
278 	   "#endif\n"
279 	   "void target_register_lib (const void *);\n\n"
280 
281 	   "__attribute__((constructor))\n"
282 	   "static void\n"
283 	   "init (void)\n"
284 	   "{\n"
285 	   "  target_register_lib (__OFFLOAD_TARGET_TABLE__);\n"
286 	   "}\n");
287   fclose (src_file);
288 
289   struct obstack argv_obstack;
290   obstack_init (&argv_obstack);
291   obstack_ptr_grow (&argv_obstack, target_compiler);
292   if (save_temps)
293     obstack_ptr_grow (&argv_obstack, "-save-temps");
294   if (verbose)
295     obstack_ptr_grow (&argv_obstack, "-v");
296   obstack_ptr_grow (&argv_obstack, "-c");
297   obstack_ptr_grow (&argv_obstack, "-shared");
298   obstack_ptr_grow (&argv_obstack, "-fPIC");
299   obstack_ptr_grow (&argv_obstack, src_filename);
300   obstack_ptr_grow (&argv_obstack, "-o");
301   obstack_ptr_grow (&argv_obstack, obj_filename);
302   compile_for_target (&argv_obstack);
303 
304   return obj_filename;
305 }
306 
307 /* Generates object file with __offload_*_end symbols for the target
308    library.  */
309 static const char *
generate_target_offloadend_file(const char * target_compiler)310 generate_target_offloadend_file (const char *target_compiler)
311 {
312   const char *src_filename = make_temp_file ("_target_offloadend.c");
313   const char *obj_filename = make_temp_file ("_target_offloadend.o");
314   temp_files[num_temps++] = src_filename;
315   temp_files[num_temps++] = obj_filename;
316   FILE *src_file = fopen (src_filename, "w");
317 
318   if (!src_file)
319     fatal_error (input_location, "cannot open '%s'", src_filename);
320 
321   fprintf (src_file,
322 	   "const void *const __offload_funcs_end[0]\n"
323 	   "__attribute__ ((__used__, visibility (\"hidden\"),\n"
324 	   "section (\".gnu.offload_funcs\"))) = { };\n\n"
325 
326 	   "const void *const __offload_vars_end[0]\n"
327 	   "__attribute__ ((__used__, visibility (\"hidden\"),\n"
328 	   "section (\".gnu.offload_vars\"))) = { };\n");
329   fclose (src_file);
330 
331   struct obstack argv_obstack;
332   obstack_init (&argv_obstack);
333   obstack_ptr_grow (&argv_obstack, target_compiler);
334   if (save_temps)
335     obstack_ptr_grow (&argv_obstack, "-save-temps");
336   if (verbose)
337     obstack_ptr_grow (&argv_obstack, "-v");
338   obstack_ptr_grow (&argv_obstack, "-c");
339   obstack_ptr_grow (&argv_obstack, "-shared");
340   obstack_ptr_grow (&argv_obstack, "-fPIC");
341   obstack_ptr_grow (&argv_obstack, src_filename);
342   obstack_ptr_grow (&argv_obstack, "-o");
343   obstack_ptr_grow (&argv_obstack, obj_filename);
344   compile_for_target (&argv_obstack);
345 
346   return obj_filename;
347 }
348 
349 /* Generates object file with the host side descriptor.  */
350 static const char *
generate_host_descr_file(const char * host_compiler)351 generate_host_descr_file (const char *host_compiler)
352 {
353   const char *src_filename = make_temp_file ("_host_descr.c");
354   const char *obj_filename = make_temp_file ("_host_descr.o");
355   temp_files[num_temps++] = src_filename;
356   temp_files[num_temps++] = obj_filename;
357   FILE *src_file = fopen (src_filename, "w");
358 
359   if (!src_file)
360     fatal_error (input_location, "cannot open '%s'", src_filename);
361 
362   fprintf (src_file,
363 	   "extern const void *const __OFFLOAD_TABLE__;\n"
364 	   "extern const void *const __offload_image_intelmic_start;\n"
365 	   "extern const void *const __offload_image_intelmic_end;\n\n"
366 
367 	   "static const void *const __offload_target_data[] = {\n"
368 	   "  &__offload_image_intelmic_start, &__offload_image_intelmic_end\n"
369 	   "};\n\n");
370 
371   fprintf (src_file,
372 	   "#ifdef __cplusplus\n"
373 	   "extern \"C\"\n"
374 	   "#endif\n"
375 	   "void GOMP_offload_register (const void *, int, const void *);\n"
376 	   "#ifdef __cplusplus\n"
377 	   "extern \"C\"\n"
378 	   "#endif\n"
379 	   "void GOMP_offload_unregister (const void *, int, const void *);\n\n"
380 
381 	   "__attribute__((constructor))\n"
382 	   "static void\n"
383 	   "init (void)\n"
384 	   "{\n"
385 	   "  GOMP_offload_register (&__OFFLOAD_TABLE__, %d, __offload_target_data);\n"
386 	   "}\n\n", GOMP_DEVICE_INTEL_MIC);
387 
388   fprintf (src_file,
389 	   "__attribute__((destructor))\n"
390 	   "static void\n"
391 	   "fini (void)\n"
392 	   "{\n"
393 	   "  GOMP_offload_unregister (&__OFFLOAD_TABLE__, %d, __offload_target_data);\n"
394 	   "}\n", GOMP_DEVICE_INTEL_MIC);
395 
396   fclose (src_file);
397 
398   struct obstack argv_obstack;
399   obstack_init (&argv_obstack);
400   obstack_ptr_grow (&argv_obstack, host_compiler);
401   if (save_temps)
402     obstack_ptr_grow (&argv_obstack, "-save-temps");
403   if (verbose)
404     obstack_ptr_grow (&argv_obstack, "-v");
405   obstack_ptr_grow (&argv_obstack, "-c");
406   obstack_ptr_grow (&argv_obstack, "-fPIC");
407   obstack_ptr_grow (&argv_obstack, "-shared");
408   switch (offload_abi)
409     {
410     case OFFLOAD_ABI_LP64:
411       obstack_ptr_grow (&argv_obstack, "-m64");
412       break;
413     case OFFLOAD_ABI_ILP32:
414       obstack_ptr_grow (&argv_obstack, "-m32");
415       break;
416     default:
417       gcc_unreachable ();
418     }
419   obstack_ptr_grow (&argv_obstack, src_filename);
420   obstack_ptr_grow (&argv_obstack, "-o");
421   obstack_ptr_grow (&argv_obstack, obj_filename);
422   obstack_ptr_grow (&argv_obstack, NULL);
423 
424   char **argv = XOBFINISH (&argv_obstack, char **);
425   fork_execute (argv[0], argv, false);
426   obstack_free (&argv_obstack, NULL);
427 
428   return obj_filename;
429 }
430 
431 static const char *
prepare_target_image(const char * target_compiler,int argc,char ** argv)432 prepare_target_image (const char *target_compiler, int argc, char **argv)
433 {
434   const char *target_descr_filename
435     = generate_target_descr_file (target_compiler);
436   const char *target_offloadend_filename
437     = generate_target_offloadend_file (target_compiler);
438 
439   char *opt1
440     = XALLOCAVEC (char, sizeof ("-Wl,") + strlen (target_descr_filename));
441   char *opt2
442     = XALLOCAVEC (char, sizeof ("-Wl,") + strlen (target_offloadend_filename));
443   sprintf (opt1, "-Wl,%s", target_descr_filename);
444   sprintf (opt2, "-Wl,%s", target_offloadend_filename);
445 
446   const char *target_so_filename = make_temp_file ("_offload_intelmic.so");
447   temp_files[num_temps++] = target_so_filename;
448   struct obstack argv_obstack;
449   obstack_init (&argv_obstack);
450   obstack_ptr_grow (&argv_obstack, target_compiler);
451   if (save_temps)
452     obstack_ptr_grow (&argv_obstack, "-save-temps");
453   if (verbose)
454     obstack_ptr_grow (&argv_obstack, "-v");
455   obstack_ptr_grow (&argv_obstack, "-xlto");
456   obstack_ptr_grow (&argv_obstack, opt1);
457   for (int i = 1; i < argc; i++)
458     {
459       if (!strcmp (argv[i], "-o") && i + 1 != argc)
460 	out_obj_filename = argv[++i];
461       else
462 	obstack_ptr_grow (&argv_obstack, argv[i]);
463     }
464   if (!out_obj_filename)
465     fatal_error (input_location, "output file not specified");
466   obstack_ptr_grow (&argv_obstack, opt2);
467   /* NB: Put -fPIC and -shared the last to create shared library.  */
468   obstack_ptr_grow (&argv_obstack, "-fPIC");
469   obstack_ptr_grow (&argv_obstack, "-shared");
470   obstack_ptr_grow (&argv_obstack, "-o");
471   obstack_ptr_grow (&argv_obstack, target_so_filename);
472   compile_for_target (&argv_obstack);
473 
474   /* Run objcopy.  */
475   char *rename_section_opt
476     = XALLOCAVEC (char, sizeof (".data=") + strlen (image_section_name));
477   sprintf (rename_section_opt, ".data=%s", image_section_name);
478   obstack_init (&argv_obstack);
479   obstack_ptr_grow (&argv_obstack, "objcopy");
480   obstack_ptr_grow (&argv_obstack, "-B");
481   obstack_ptr_grow (&argv_obstack, "i386");
482   obstack_ptr_grow (&argv_obstack, "-I");
483   obstack_ptr_grow (&argv_obstack, "binary");
484   obstack_ptr_grow (&argv_obstack, "-O");
485   switch (offload_abi)
486     {
487     case OFFLOAD_ABI_LP64:
488       obstack_ptr_grow (&argv_obstack, "elf64-x86-64");
489       break;
490     case OFFLOAD_ABI_ILP32:
491       obstack_ptr_grow (&argv_obstack, "elf32-i386");
492       break;
493     default:
494       gcc_unreachable ();
495     }
496   obstack_ptr_grow (&argv_obstack, target_so_filename);
497   obstack_ptr_grow (&argv_obstack, "--rename-section");
498   obstack_ptr_grow (&argv_obstack, rename_section_opt);
499   obstack_ptr_grow (&argv_obstack, NULL);
500   char **new_argv = XOBFINISH (&argv_obstack, char **);
501   fork_execute (new_argv[0], new_argv, false);
502   obstack_free (&argv_obstack, NULL);
503 
504   /* Objcopy has created symbols, containing the input file name with
505      non-alphanumeric characters replaced by underscores.
506      We are going to rename these new symbols.  */
507   size_t symbol_name_len = strlen (target_so_filename);
508   char *symbol_name = XALLOCAVEC (char, symbol_name_len + 1);
509   for (size_t i = 0; i < symbol_name_len; i++)
510     {
511       char c = target_so_filename[i];
512       if (!ISALNUM (c))
513 	c = '_';
514       symbol_name[i] = c;
515     }
516   symbol_name[symbol_name_len] = '\0';
517 
518   char *opt_for_objcopy[3];
519   opt_for_objcopy[0] = XALLOCAVEC (char, sizeof ("_binary__start=")
520 					 + symbol_name_len
521 					 + strlen (symbols[0]));
522   opt_for_objcopy[1] = XALLOCAVEC (char, sizeof ("_binary__end=")
523 					 + symbol_name_len
524 					 + strlen (symbols[1]));
525   opt_for_objcopy[2] = XALLOCAVEC (char, sizeof ("_binary__size=")
526 					 + symbol_name_len
527 					 + strlen (symbols[2]));
528   sprintf (opt_for_objcopy[0], "_binary_%s_start=%s", symbol_name, symbols[0]);
529   sprintf (opt_for_objcopy[1], "_binary_%s_end=%s", symbol_name, symbols[1]);
530   sprintf (opt_for_objcopy[2], "_binary_%s_size=%s", symbol_name, symbols[2]);
531 
532   obstack_init (&argv_obstack);
533   obstack_ptr_grow (&argv_obstack, "objcopy");
534   obstack_ptr_grow (&argv_obstack, target_so_filename);
535   obstack_ptr_grow (&argv_obstack, "--redefine-sym");
536   obstack_ptr_grow (&argv_obstack, opt_for_objcopy[0]);
537   obstack_ptr_grow (&argv_obstack, "--redefine-sym");
538   obstack_ptr_grow (&argv_obstack, opt_for_objcopy[1]);
539   obstack_ptr_grow (&argv_obstack, "--redefine-sym");
540   obstack_ptr_grow (&argv_obstack, opt_for_objcopy[2]);
541   obstack_ptr_grow (&argv_obstack, NULL);
542   new_argv = XOBFINISH (&argv_obstack, char **);
543   fork_execute (new_argv[0], new_argv, false);
544   obstack_free (&argv_obstack, NULL);
545 
546   return target_so_filename;
547 }
548 
549 int
main(int argc,char ** argv)550 main (int argc, char **argv)
551 {
552   progname = "mkoffload-intelmic";
553   gcc_init_libintl ();
554   diagnostic_initialize (global_dc, 0);
555 
556   if (atexit (mkoffload_cleanup) != 0)
557     fatal_error (input_location, "atexit failed");
558 
559   const char *host_compiler = getenv ("COLLECT_GCC");
560   if (!host_compiler)
561     fatal_error (input_location, "COLLECT_GCC must be set");
562 
563   const char *target_driver_name = GCC_INSTALL_NAME;
564   char *target_compiler = find_target_compiler (target_driver_name);
565   if (target_compiler == NULL)
566     fatal_error (input_location, "offload compiler %s not found",
567 		 target_driver_name);
568 
569   /* We may be called with all the arguments stored in some file and
570      passed with @file.  Expand them into argv before processing.  */
571   expandargv (&argc, &argv);
572 
573   /* Scan the argument vector.  */
574   for (int i = 1; i < argc; i++)
575     {
576 #define STR "-foffload-abi="
577       if (strncmp (argv[i], STR, strlen (STR)) == 0)
578 	{
579 	  if (strcmp (argv[i] + strlen (STR), "lp64") == 0)
580 	    offload_abi = OFFLOAD_ABI_LP64;
581 	  else if (strcmp (argv[i] + strlen (STR), "ilp32") == 0)
582 	    offload_abi = OFFLOAD_ABI_ILP32;
583 	  else
584 	    fatal_error (input_location,
585 			 "unrecognizable argument of option " STR);
586 	}
587 #undef STR
588       else if (strcmp (argv[i], "-save-temps") == 0)
589 	save_temps = true;
590       else if (strcmp (argv[i], "-v") == 0)
591 	verbose = true;
592     }
593 
594   const char *target_so_filename
595     = prepare_target_image (target_compiler, argc, argv);
596 
597   const char *host_descr_filename = generate_host_descr_file (host_compiler);
598 
599   /* Perform partial linking for the target image and host side descriptor.
600      As a result we'll get a finalized object file with all offload data.  */
601   struct obstack argv_obstack;
602   obstack_init (&argv_obstack);
603   obstack_ptr_grow (&argv_obstack, "ld");
604   obstack_ptr_grow (&argv_obstack, "-m");
605   switch (offload_abi)
606     {
607     case OFFLOAD_ABI_LP64:
608       obstack_ptr_grow (&argv_obstack, "elf_x86_64");
609       break;
610     case OFFLOAD_ABI_ILP32:
611       obstack_ptr_grow (&argv_obstack, "elf_i386");
612       break;
613     default:
614       gcc_unreachable ();
615     }
616   obstack_ptr_grow (&argv_obstack, "--relocatable");
617   obstack_ptr_grow (&argv_obstack, host_descr_filename);
618   obstack_ptr_grow (&argv_obstack, target_so_filename);
619   obstack_ptr_grow (&argv_obstack, "-o");
620   obstack_ptr_grow (&argv_obstack, out_obj_filename);
621   obstack_ptr_grow (&argv_obstack, NULL);
622   char **new_argv = XOBFINISH (&argv_obstack, char **);
623   fork_execute (new_argv[0], new_argv, false);
624   obstack_free (&argv_obstack, NULL);
625 
626   /* Run objcopy on the resultant object file to localize generated symbols
627      to avoid conflicting between different DSO and an executable.  */
628   obstack_init (&argv_obstack);
629   obstack_ptr_grow (&argv_obstack, "objcopy");
630   obstack_ptr_grow (&argv_obstack, "-L");
631   obstack_ptr_grow (&argv_obstack, symbols[0]);
632   obstack_ptr_grow (&argv_obstack, "-L");
633   obstack_ptr_grow (&argv_obstack, symbols[1]);
634   obstack_ptr_grow (&argv_obstack, "-L");
635   obstack_ptr_grow (&argv_obstack, symbols[2]);
636   obstack_ptr_grow (&argv_obstack, out_obj_filename);
637   obstack_ptr_grow (&argv_obstack, NULL);
638   new_argv = XOBFINISH (&argv_obstack, char **);
639   fork_execute (new_argv[0], new_argv, false);
640   obstack_free (&argv_obstack, NULL);
641 
642   return 0;
643 }
644