[PATCH]: random global function name

[Nathan Sidwell <nathan at codesourcery dot com>]

Hi,
This patch replaces the append_random_chars function with a crc32, and
hence removes a use of clean_symbol_name -- it seems silly to generate
a random string in a complicated manner, and then strip it of bogus chars.
The crc32_string function will be used from elsewhere.

booted & tested on i686-pc-linux-gnu, ok?

nathan
--
Nathan Sidwell    ::   http://www.codesourcery.com   ::     CodeSourcery LLC
         The voices in my head said this was stupid too
nathan@codesourcery.com    ::     http://www.planetfall.pwp.blueyonder.co.uk

2003-07-05  Nathan Sidwell  <nathan@codesourcery.com>

	* tree.h (crc32_string): Declare.
	* tree.c (append_random_chars): Remove.
	(crc32_string): New.
	(get_file_function_name_long): Use crc32_string here.

Index: tree.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/tree.c,v
retrieving revision 1.310
diff -c -3 -p -r1.310 tree.c
*** tree.c	29 Jun 2003 11:28:00 -0000	1.310
--- tree.c	5 Jul 2003 15:36:08 -0000
*************** static GTY ((if_marked ("type_hash_marke
*** 119,125 ****
       htab_t type_hash_table;
  
  static void set_type_quals PARAMS ((tree, int));
- static void append_random_chars PARAMS ((char *));
  static int type_hash_eq PARAMS ((const void *, const void *));
  static hashval_t type_hash_hash PARAMS ((const void *));
  static void print_type_hash_statistics PARAMS((void));
--- 119,124 ----
*************** default_flag_random_seed (void)
*** 4647,4691 ****
    flag_random_seed = new_random_seed;
  }
  
! /* 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";
!   unsigned HOST_WIDE_INT v;
!   size_t i;
! 
!   default_flag_random_seed ();
! 
!   /* This isn't a very good hash, but it does guarantee no collisions 
!      when the random string is generated by the code above and the time
!      delta is small.  */
!   v = 0;
!   for (i = 0; i < strlen (flag_random_seed); i++)
!     v = (v << 4) ^ (v >> (HOST_BITS_PER_WIDE_INT - 4)) ^ flag_random_seed[i];
! 
!   template += strlen (template);
! 
!   /* 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';
  }
  
  /* P is a string that will be used in a symbol.  Mask out any characters
--- 4646,4674 ----
    flag_random_seed = new_random_seed;
  }
  
! /* Generate a crc32 of a string.  */
!   
! unsigned
! crc32_string (chksum, string)
!      unsigned chksum;
!      const char *string;
! {
!   do
!     {
!       unsigned value = *string << 24;
!       unsigned ix;
!       
!       for (ix = 8; ix--; value <<= 1)
!  	{
!  	  unsigned feedback;
!  	  
!  	  feedback = (value ^ chksum) & 0x80000000 ? 0x04c11db7 : 0;
! 	  chksum <<= 1;
! 	  chksum ^= feedback;
!  	}
!     }
!   while (*string++);
!   return chksum;
  }
  
  /* P is a string that will be used in a symbol.  Mask out any characters
*************** get_file_function_name_long (type)
*** 4725,4731 ****
      {
        /* 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.  */
! 
        const char *name = weak_global_object_name;
        const char *file = main_input_filename;
  
--- 4708,4714 ----
      {
        /* 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.  */
!       unsigned len;
        const char *name = weak_global_object_name;
        const char *file = main_input_filename;
  
*************** get_file_function_name_long (type)
*** 4734,4743 ****
        if (! file)
  	file = input_filename;
  
!       q = (char *) alloca (7 + strlen (name) + strlen (file));
  
-       sprintf (q, "%s%s", name, file);
-       append_random_chars (q);
        p = q;
      }
  
--- 4717,4731 ----
        if (! file)
  	file = input_filename;
  
!       len = strlen (file);
!       q = (char *) alloca (9 * 2 + len);
!       memcpy (q, file, len + 1);
!       clean_symbol_name (q);
! 
!       default_flag_random_seed ();
!       sprintf (q + len, "_%08X_08X", crc32_string (0, name),
! 	       crc32_string (0, flag_random_seed));
  
        p = q;
      }
  
*************** get_file_function_name_long (type)
*** 4749,4758 ****
       the program) rather than the file name (which imposes extra
       constraints).  */
    sprintf (buf, FILE_FUNCTION_FORMAT, type, p);
- 
-   /* Don't need to pull weird characters out of global names.  */
-   if (p != first_global_object_name)
-     clean_symbol_name (buf + 11);
  
    return get_identifier (buf);
  }
--- 4737,4742 ----
Index: tree.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/tree.h,v
retrieving revision 1.418
diff -c -3 -p -r1.418 tree.h
*** tree.h	1 Jul 2003 02:04:11 -0000	1.418
--- tree.h	5 Jul 2003 15:36:16 -0000
*************** extern tree builtin_function		PARAMS ((c
*** 2648,2653 ****
--- 2648,2654 ----
  					       const char *, tree));
  
  /* In tree.c */
+ extern unsigned crc32_string		PARAMS ((unsigned, const char *));
  extern void clean_symbol_name			PARAMS ((char *));
  extern tree get_file_function_name_long 	PARAMS ((const char *));
  extern tree get_set_constructor_bits		PARAMS ((tree, char *, int));