diff options
author | jb <jb@138bc75d-0d04-0410-961f-82ee72b054a4> | 2016-08-19 14:12:32 +0000 |
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committer | jb <jb@138bc75d-0d04-0410-961f-82ee72b054a4> | 2016-08-19 14:12:32 +0000 |
commit | ee0e163a21bb70f9fee44b1ab50bd7d6e81275bc (patch) | |
tree | 3dd25be020bc1f538120f175d6ec7627ccda7699 /libgfortran | |
parent | fdabea44ff9c943fa0a0e77f8816043c74afe105 (diff) |
Always initialize PRNG using random data from the OS.
libgfortran:
2016-08-16 Janne Blomqvist <jb@gcc.gnu.org>
* intrinsics/random.c (master_init): New variable.
(init_rand_state): Move below getosrandom (), maybe initialize
master_state.
(random_seed_i4): If called with no arguments, set master_init to
false, and reinitialize. If called with PUT=, set master_init to
true.
(random_seed_i8): Likewise.
testsuite:
2016-08-16 Janne Blomqvist <jb@gcc.gnu.org>
* gfortran.dg/random_4.f90: Initialize seed before using, handle
the last special seed value.
* gfortran.dg/random_7.f90: Use size for last array member instead
of hardcoded value.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@239611 138bc75d-0d04-0410-961f-82ee72b054a4
Diffstat (limited to 'libgfortran')
-rw-r--r-- | libgfortran/ChangeLog | 10 | ||||
-rw-r--r-- | libgfortran/intrinsics/random.c | 57 |
2 files changed, 42 insertions, 25 deletions
diff --git a/libgfortran/ChangeLog b/libgfortran/ChangeLog index 0f9d629b460..6fd12228645 100644 --- a/libgfortran/ChangeLog +++ b/libgfortran/ChangeLog @@ -1,3 +1,13 @@ +2016-08-16 Janne Blomqvist <jb@gcc.gnu.org> + + * intrinsics/random.c (master_init): New variable. + (init_rand_state): Move below getosrandom (), maybe initialize + master_state. + (random_seed_i4): If called with no arguments, set master_init to + false, and reinitialize. If called with PUT=, set master_init to + true. + (random_seed_i8): Likewise. + 2016-08-11 Rainer Orth <ro@CeBiTec.Uni-Bielefeld.DE> * intrinsics/random.c: Include <stdlib.h>. diff --git a/libgfortran/intrinsics/random.c b/libgfortran/intrinsics/random.c index 3b913893817..35c76113b1a 100644 --- a/libgfortran/intrinsics/random.c +++ b/libgfortran/intrinsics/random.c @@ -193,9 +193,10 @@ typedef struct xorshift1024star_state; -/* How many times we have jumped. This and master_state are the only - variables protected by random_lock. */ -static unsigned njumps; +/* master_init, njumps, and master_state are the only variables + protected by random_lock. */ +static bool master_init; +static unsigned njumps; /* How many times we have jumped. */ static uint64_t master_state[] = { 0xad63fa1ed3b55f36ULL, 0xd94473e78978b497ULL, 0xbc60592a98172477ULL, 0xa3de7c6e81265301ULL, 0x586640c5e785af27ULL, 0x7a2a3f63b67ce5eaULL, @@ -272,24 +273,6 @@ jump (xorshift1024star_state* rs) } -/* Initialize the random number generator for the current thread, - using the master state and the number of times we must jump. */ - -static void -init_rand_state (xorshift1024star_state* rs, const bool locked) -{ - if (!locked) - __gthread_mutex_lock (&random_lock); - memcpy (&rs->s, master_state, sizeof (master_state)); - unsigned n = njumps++; - if (!locked) - __gthread_mutex_unlock (&random_lock); - for (unsigned i = 0; i < n; i++) - jump (rs); - rs->init = true; -} - - /* Super-simple LCG generator used in getosrandom () if /dev/urandom doesn't exist. */ @@ -359,6 +342,30 @@ getosrandom (void *buf, size_t buflen) } +/* Initialize the random number generator for the current thread, + using the master state and the number of times we must jump. */ + +static void +init_rand_state (xorshift1024star_state* rs, const bool locked) +{ + if (!locked) + __gthread_mutex_lock (&random_lock); + if (!master_init) + { + getosrandom (master_state, sizeof (master_state)); + njumps = 0; + master_init = true; + } + memcpy (&rs->s, master_state, sizeof (master_state)); + unsigned n = njumps++; + if (!locked) + __gthread_mutex_unlock (&random_lock); + for (unsigned i = 0; i < n; i++) + jump (rs); + rs->init = true; +} + + /* This function produces a REAL(4) value from the uniform distribution with range [0,1). */ @@ -791,8 +798,7 @@ random_seed_i4 (GFC_INTEGER_4 *size, gfc_array_i4 *put, gfc_array_i4 *get) a processor-dependent value to the seed." */ if (size == NULL && put == NULL && get == NULL) { - getosrandom (master_state, sizeof (master_state)); - njumps = 0; + master_init = false; init_rand_state (rs, true); } @@ -816,6 +822,7 @@ random_seed_i4 (GFC_INTEGER_4 *size, gfc_array_i4 *put, gfc_array_i4 *get) provide seeds with quality only in the lower or upper part. */ scramble_seed ((unsigned char *) master_state, seed, sizeof seed); njumps = 0; + master_init = true; init_rand_state (rs, true); rs->p = put->base_addr[SZ * GFC_DESCRIPTOR_STRIDE(put, 0)] & 15; @@ -873,8 +880,7 @@ random_seed_i8 (GFC_INTEGER_8 *size, gfc_array_i8 *put, gfc_array_i8 *get) a processor-dependent value to the seed." */ if (size == NULL && put == NULL && get == NULL) { - getosrandom (master_state, sizeof (master_state)); - njumps = 0; + master_init = false; init_rand_state (rs, true); } @@ -894,6 +900,7 @@ random_seed_i8 (GFC_INTEGER_8 *size, gfc_array_i8 *put, gfc_array_i8 *get) sizeof (GFC_UINTEGER_8)); njumps = 0; + master_init = true; init_rand_state (rs, true); rs->p = put->base_addr[SZ * GFC_DESCRIPTOR_STRIDE(put, 0)] & 15; } |