Patch to get_file_function_name_long

[Jason Merrill <jason at cygnus dot com>]

If we don't have a known-unique key to generate file functions from, we
have to approximate one.  This patch improves that approximation by adding
randomness.

Fixes g++.pt/instantiate5.C.  Applied.

Wed Oct 28 22:58:35 1998  Jason Merrill  <jason@yorick.cygnus.com>

	* tree.c (append_random_chars): New fn.
	(get_file_function_name_long): Use it.

Index: tree.c
===================================================================
RCS file: /egcs/carton/cvsfiles/egcs/gcc/tree.c,v
retrieving revision 1.47
diff -c -p -r1.47 tree.c
*** tree.c	1998/10/21 09:53:38	1.47
--- tree.c	1998/10/29 06:58:22
*************** int (*lang_get_alias_set) PROTO((tree));
*** 265,270 ****
--- 265,271 ----
  #define TYPE_HASH(TYPE) ((unsigned long) (TYPE) & 0777777)
  
  static void set_type_quals PROTO((tree, int));
+ static void append_random_chars PROTO((char *));
  
  extern char *mode_name[];
  
*************** dump_tree_statistics ()
*** 4820,4828 ****
  extern char * first_global_object_name;
  extern char * weak_global_object_name;
  
! /* TYPE is some string to identify this function to the linker or
!    collect2.  */
  
  tree
  get_file_function_name_long (type)
       char *type;
--- 4821,4876 ----
  extern char * first_global_object_name;
  extern char * weak_global_object_name;
  
! /* Appends 6 random characters to TEMPLATE to (hopefully) avoid name
!    clashes in cases where we can't reliably choose a unique name.
  
+    Derived from mkstemp.c in libiberty.  */
+ 
+ static void
+ append_random_chars (template)
+      char *template;
+ {
+   static const char letters[]
+     = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
+   static unsigned HOST_WIDE_INT value;
+   unsigned HOST_WIDE_INT v;
+ 
+ #ifdef HAVE_GETTIMEOFDAY
+   struct timeval tv;
+ #endif
+ 
+   template += strlen (template);
+ 
+ #ifdef HAVE_GETTIMEOFDAY
+   /* Get some more or less random data.  */
+   gettimeofday (&tv, NULL);
+   value += ((unsigned HOST_WIDE_INT) tv.tv_usec << 16) ^ tv.tv_sec ^ getpid ();
+ #else
+   value += getpid ();
+ #endif
+ 
+   v = value;
+ 
+   /* Fill in the random bits.  */
+   template[0] = letters[v % 62];
+   v /= 62;
+   template[1] = letters[v % 62];
+   v /= 62;
+   template[2] = letters[v % 62];
+   v /= 62;
+   template[3] = letters[v % 62];
+   v /= 62;
+   template[4] = letters[v % 62];
+   v /= 62;
+   template[5] = letters[v % 62];
+ 
+   template[6] = '\0';
+ }
+ 
+ /* Generate a name for a function unique to this translation unit.
+    TYPE is some string to identify the purpose of this function to the
+    linker or collect2.  */
+ 
  tree
  get_file_function_name_long (type)
       char *type;
*************** get_file_function_name_long (type)
*** 4832,4843 ****
  
    if (first_global_object_name)
      p = first_global_object_name;
-   else if (weak_global_object_name)
-     p = weak_global_object_name;
-   else if (main_input_filename)
-     p = main_input_filename;
    else
!     p = input_filename;
  
    buf = (char *) alloca (sizeof (FILE_FUNCTION_FORMAT) + strlen (p)
  			 + strlen (type));
--- 4880,4903 ----
  
    if (first_global_object_name)
      p = first_global_object_name;
    else
!     {
!       /* We don't have anything that we know to be unique to this translation
! 	 unit, so use what we do have and throw in some randomness.  */
! 
!       char *name = weak_global_object_name;
!       char *file = main_input_filename;
! 
!       if (! name)
! 	name = "";
!       if (! file)
! 	file = input_filename;
! 
!       p = (char *) alloca (7 + strlen (name) + strlen (file));
! 
!       sprintf (p, "%s%s", name, file);
!       append_random_chars (p);
!     }
  
    buf = (char *) alloca (sizeof (FILE_FUNCTION_FORMAT) + strlen (p)
  			 + strlen (type));