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author | ak <ak@138bc75d-0d04-0410-961f-82ee72b054a4> | 2011-09-29 13:14:51 +0000 |
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committer | ak <ak@138bc75d-0d04-0410-961f-82ee72b054a4> | 2011-09-29 13:14:51 +0000 |
commit | badc6cfaaad34c28dcf83d4773943e589bd47322 (patch) | |
tree | 572521c2983256f9fae580c8be83c1898f33a849 /gcc/cp/repo.c | |
parent | 5684c61c0def2f1ad31c094d19977a66681c6e87 (diff) | |
download | gcc-badc6cfaaad34c28dcf83d4773943e589bd47322.tar.gz |
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
Diffstat (limited to 'gcc/cp/repo.c')
-rw-r--r-- | gcc/cp/repo.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/gcc/cp/repo.c b/gcc/cp/repo.c index 16a192e4de9..ca971b61b59 100644 --- a/gcc/cp/repo.c +++ b/gcc/cp/repo.c @@ -263,7 +263,8 @@ finish_repo (void) anonymous namespaces will get the same mangling when this file is recompiled. */ if (!strstr (args, "'-frandom-seed=")) - fprintf (repo_file, " '-frandom-seed=%s'", get_random_seed (false)); + fprintf (repo_file, " '-frandom-seed=" HOST_WIDE_INT_PRINT_HEX_PURE "'", + get_random_seed (false)); fprintf (repo_file, "\n"); } |