lto wrapper verboseness

[Nathan Sidwell]

Jakub,
this patch augments the lto wrapper to print out the arguments to spawned 
commands when verbose.  I found this useful in debugging recent development.

ok for trunk?

nathan
2015-07-29  Nathan Sidwell  <nat...@codesourcery.com>

	* lto-wrapper.c (verbose_exec): New.
	(compile_offload_image, run_gcc): Call it.

Index: gcc/lto-wrapper.c
===================================================================
--- gcc/lto-wrapper.c	(revision 226372)
+++ gcc/lto-wrapper.c	(working copy)
@@ -115,6 +115,15 @@ maybe_unlink (const char *file)
     fprintf (stderr, "[Leaving LTRANS %s]\n", file);
 }
 
+/* Print command being executed.  */
+static void
+verbose_exec (const char *const *argv)
+{
+  while (*argv)
+    fprintf (stderr, " %s", *argv++);
+  fprintf (stderr, "\n");
+}
+
 /* Template of LTRANS dumpbase suffix.  */
 #define DUMPBASE_SUFFIX ".ltrans18446744073709551615"
 
@@ -693,6 +702,8 @@ compile_offload_image (const char *targe
 
       obstack_ptr_grow (&argv_obstack, NULL);
       argv = XOBFINISH (&argv_obstack, char **);
+      if (verbose)
+	verbose_exec (argv);
       fork_execute (argv[0], argv, true);
       obstack_free (&argv_obstack, NULL);
     }
@@ -1156,6 +1167,8 @@ run_gcc (unsigned argc, char *argv[])
 
   new_argv = XOBFINISH (&argv_obstack, const char **);
   argv_ptr = &new_argv[new_head_argc];
+  if (verbose)
+    verbose_exec (new_argv);
   fork_execute (new_argv[0], CONST_CAST (char **, new_argv), true);
 
   if (lto_mode == LTO_MODE_LTO)
@@ -1264,6 +1277,8 @@ cont:
 	    }
 	  else
 	    {
+	      if (verbose)
+		verbose_exec (new_argv);
 	      fork_execute (new_argv[0], CONST_CAST (char **, new_argv),
 			    true);
 	      maybe_unlink (input_name);