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author | Andi Kleen <ak@linux.intel.com> | 2011-09-29 13:14:51 +0000 |
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committer | Andi Kleen <ak@gcc.gnu.org> | 2011-09-29 13:14:51 +0000 |
commit | dde8b3609b40a5e9073a7638d492b8c29af2e24c (patch) | |
tree | 572521c2983256f9fae580c8be83c1898f33a849 /gcc/tree.c | |
parent | 4056cc1ba5e5590529b257a12f80270d552019b9 (diff) | |
download | gcc-dde8b3609b40a5e9073a7638d492b8c29af2e24c.zip gcc-dde8b3609b40a5e9073a7638d492b8c29af2e24c.tar.gz gcc-dde8b3609b40a5e9073a7638d492b8c29af2e24c.tar.bz2 |
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.
From-SVN: r179347
Diffstat (limited to 'gcc/tree.c')
-rw-r--r-- | gcc/tree.c | 6 |
1 files changed, 3 insertions, 3 deletions
@@ -8749,11 +8749,11 @@ get_file_function_name (const char *type) file = input_filename; len = strlen (file); - q = (char *) alloca (9 * 2 + len + 1); + q = (char *) alloca (9 + 17 + len + 1); memcpy (q, file, len + 1); - sprintf (q + len, "_%08X_%08X", crc32_string (0, name), - crc32_string (0, get_random_seed (false))); + snprintf (q + len, 9 + 17 + 1, "_%08X_" HOST_WIDE_INT_PRINT_HEX, + crc32_string (0, name), get_random_seed (false)); p = q; } |