collect2.c (may_unlink_output_file): New global.

* collect2.c (may_unlink_output_file): New global.
        (maybe_unlink): Honor it.
        * collect2.h: Add extern for it.
        * tlink.c (do_tlink): Set it to true if the link succeeded.

From-SVN: r187148

gcc/ChangeLog

@@ -1,3 +1,10 @@
+2012-05-04  Olivier Hainque  <hainque@adacore.com>
+
+	* collect2.c (may_unlink_output_file): New global.
+	(maybe_unlink): Honor it.
+	* collect2.h: Add extern for it.
+	* tlink.c (do_tlink): Set it to true if the link succeeded.
+
 2012-05-04  Olivier Hainque  <hainque@adacore.com>
 
 	* gcc.c (eval_spec_function): Finalize/restore the current string

gcc/collect2.c

@@ -237,6 +237,12 @@ static const char *target_system_root = TARGET_SYSTEM_ROOT;
 static const char *target_system_root = "";
 #endif
 
+/* Whether we may unlink the output file, which should be set as soon as we
+   know we have successfully produced it.  This is typically useful to prevent
+   blindly attempting to unlink a read-only output that the target linker
+   would leave untouched.  */
+bool may_unlink_output_file = false;
+
 /* Structure to hold all the directories in which to search for files to
    execute.  */
 
@@ -2095,15 +2101,22 @@ fork_execute (const char *prog, char **argv)
   do_wait (prog, pex);
 }
 
-/* Unlink a file unless we are debugging.  */
+/* Unlink FILE unless we are debugging or this is the output_file
+   and we may not unlink it.  */
 
 static void
 maybe_unlink (const char *file)
 {
-  if (!debug)
-    unlink_if_ordinary (file);
-  else
-    notice ("[Leaving %s]\n", file);
+  if (debug)
+    {
+      notice ("[Leaving %s]\n", file);
+      return;
+    }
+
+  if (file == output_file && !may_unlink_output_file)
+    return;
+
+  unlink_if_ordinary (file);
 }
 
 /* Call maybe_unlink on the NULL-terminated list, FILE_LIST.  */

gcc/collect2.h

@@ -40,6 +40,7 @@ extern const char *c_file_name;
 extern struct obstack temporary_obstack;
 extern char *temporary_firstobj;
 extern bool vflag, debug;
+extern bool may_unlink_output_file;
 
 extern void notice_translated (const char *, ...) ATTRIBUTE_PRINTF_1;
 extern void notice (const char *, ...) ATTRIBUTE_PRINTF_1;

gcc/tlink.c

@@ -859,4 +859,10 @@ do_tlink (char **ld_argv, char **object_lst ATTRIBUTE_UNUSED)
       error ("ld returned %d exit status", exit);
       collect_exit (exit);
     }
+  else
+    {
+      /* We have just successfully produced an output file, so assume that we
+	 may unlink it if need be for now on.  */ 
+      may_unlink_output_file = true;
+    }
 }