Change random seeds to 64bit and drop re-crcing

I had some trouble with random build failures in a large LTO project
and it turned out to be random seed collisions in a highly parallel build
(thanks to Honza for suggesting that)

There were multiple problems:
- The way to generate the random seed is not very random (milliseconds time plus pid)
and prone to collisions on highly parallel builds
- It's only 32bit
- Several users take the existing ascii seed and re-CRC32 it again, which
doesn't exactly improve it.

This patch changes that to:
- Always use 64bit seeds as numbers (no re-crcing)
- Change all users to use HOST_WIDE_INT
- When the user specifies a random seed it's still crc32ed, but only in
this case.

Passes bootstrap + testsuite on x86_64-linux.

gcc/cp:

2011-09-26   Andi Kleen <ak@linux.intel.com>

	* repo.c (finish_repo): Use HOST_WIDE_INT_PRINT_HEX_PURE.

gcc/:

2011-09-26   Andi Kleen <ak@linux.intel.com>

	* hwint.h (HOST_WIDE_INT_PRINT_HEX_PURE): Add.
	* lto-streamer.c (lto_get_section_name): Remove crc32_string.
 	Handle numerical random seed.
	* lto-streamer.h (lto_file_decl_data): Change id to unsigned HOST_WIDE_INT.
	* toplev.c (random_seed): Add.
	(init_random_seed): Change for numerical random seed.
	(get_random_seed): Return as HOST_WIDE_INT.
	(set_random_seed): Crc32 existing string.
	* toplev.h (get_random_seed): Change to numercal return.
	* tree.c (get_file_function_name): Remove CRC. Handle numerical random seed.

gcc/lto/:

2011-09-26   Andi Kleen <ak@linux.intel.com>

	* lto.c (lto_resolution_read): Remove id dumping.
	(lto_section_with_id): Turn id HOST_WIDE_ID.
	(create_subid_section_table): Dito.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@179347 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 4 insertions, 4 deletions

diff --git a/gcc/lto-streamer.c b/gcc/lto-streamer.c
index 633c3ce4d50..e3ccb79d813 100644
--- a/gcc/lto-streamer.c
+++ b/gcc/lto-streamer.c
@@ -166,13 +166,13 @@ lto_get_section_name (int section_type, const char *name, struct lto_file_decl_d
      doesn't confuse the reader with merged sections.
 
      For options don't add a ID, the option reader cannot deal with them
-     and merging should be ok here.
-
-     XXX: use crc64 to minimize collisions? */
+     and merging should be ok here. */
   if (section_type == LTO_section_opts)
     strcpy (post, "");
+  else if (f != NULL) 
+    sprintf (post, "." HOST_WIDE_INT_PRINT_HEX_PURE, f->id);
   else
-    sprintf (post, ".%x", f ? f->id : crc32_string(0, get_random_seed (false)));
+    sprintf (post, "." HOST_WIDE_INT_PRINT_HEX_PURE, get_random_seed (false)); 
   return concat (LTO_SECTION_NAME_PREFIX, sep, add, post, NULL);
 }