From 9b75808be171cc7c586e32ddb9d5dd86eca38669 Mon Sep 17 00:00:00 2001 From: David Goldblatt Date: Wed, 2 Dec 2020 19:06:32 -0800 Subject: [PATCH] flat bitmap: Add a bitwise and/or/not. We're about to need them. --- include/jemalloc/internal/flat_bitmap.h | 30 ++++++ test/unit/flat_bitmap.c | 132 +++++++++++++++++++++++- 2 files changed, 161 insertions(+), 1 deletion(-) diff --git a/include/jemalloc/internal/flat_bitmap.h b/include/jemalloc/internal/flat_bitmap.h index c8cf518a..90c4091f 100644 --- a/include/jemalloc/internal/flat_bitmap.h +++ b/include/jemalloc/internal/flat_bitmap.h @@ -340,4 +340,34 @@ fb_urange_longest(fb_group_t *fb, size_t nbits) { return fb_range_longest_impl(fb, nbits, /* val */ false); } +/* + * Initializes each bit of dst with the bitwise-AND of the corresponding bits of + * src1 and src2. All bitmaps must be the same size. + */ +static inline void +fb_bit_and(fb_group_t *dst, fb_group_t *src1, fb_group_t *src2, size_t nbits) { + size_t ngroups = FB_NGROUPS(nbits); + for (size_t i = 0; i < ngroups; i++) { + dst[i] = src1[i] & src2[i]; + } +} + +/* Like fb_bit_and, but with bitwise-OR. */ +static inline void +fb_bit_or(fb_group_t *dst, fb_group_t *src1, fb_group_t *src2, size_t nbits) { + size_t ngroups = FB_NGROUPS(nbits); + for (size_t i = 0; i < ngroups; i++) { + dst[i] = src1[i] | src2[i]; + } +} + +/* Initializes dst bit i to the negation of source bit i. */ +static inline void +fb_bit_not(fb_group_t *dst, fb_group_t *src, size_t nbits) { + size_t ngroups = FB_NGROUPS(nbits); + for (size_t i = 0; i < ngroups; i++) { + dst[i] = ~src[i]; + } +} + #endif /* JEMALLOC_INTERNAL_FB_H */ diff --git a/test/unit/flat_bitmap.c b/test/unit/flat_bitmap.c index f0883790..6b0bcc34 100644 --- a/test/unit/flat_bitmap.c +++ b/test/unit/flat_bitmap.c @@ -807,6 +807,133 @@ TEST_BEGIN(test_count_alternating) { } TEST_END +static void +do_test_bit_op(size_t nbits, bool (*op)(bool a, bool b), + void (*fb_op)(fb_group_t *dst, fb_group_t *src1, fb_group_t *src2, size_t nbits)) { + size_t sz = FB_NGROUPS(nbits) * sizeof(fb_group_t); + fb_group_t *fb1 = malloc(sz); + fb_group_t *fb2 = malloc(sz); + fb_group_t *fb_result = malloc(sz); + fb_init(fb1, nbits); + fb_init(fb2, nbits); + fb_init(fb_result, nbits); + + /* Just two random numbers. */ + const uint64_t prng_init1 = (uint64_t)0X4E9A9DE6A35691CDULL; + const uint64_t prng_init2 = (uint64_t)0X7856E396B063C36EULL; + + uint64_t prng1 = prng_init1; + uint64_t prng2 = prng_init2; + + for (size_t i = 0; i < nbits; i++) { + bool bit1 = ((prng1 & (1ULL << (i % 64))) != 0); + bool bit2 = ((prng2 & (1ULL << (i % 64))) != 0); + + if (bit1) { + fb_set(fb1, nbits, i); + } + if (bit2) { + fb_set(fb2, nbits, i); + } + + if (i % 64 == 0) { + prng1 = prng_state_next_u64(prng1); + prng2 = prng_state_next_u64(prng2); + } + } + + fb_op(fb_result, fb1, fb2, nbits); + + /* Reset the prngs to replay them. */ + prng1 = prng_init1; + prng2 = prng_init2; + + for (size_t i = 0; i < nbits; i++) { + bool bit1 = ((prng1 & (1ULL << (i % 64))) != 0); + bool bit2 = ((prng2 & (1ULL << (i % 64))) != 0); + + /* Original bitmaps shouldn't change. */ + expect_b_eq(bit1, fb_get(fb1, nbits, i), "difference at bit %zu", i); + expect_b_eq(bit2, fb_get(fb2, nbits, i), "difference at bit %zu", i); + + /* New one should be bitwise and. */ + expect_b_eq(op(bit1, bit2), fb_get(fb_result, nbits, i), + "difference at bit %zu", i); + + /* Update the same way we did last time. */ + if (i % 64 == 0) { + prng1 = prng_state_next_u64(prng1); + prng2 = prng_state_next_u64(prng2); + } + } + + free(fb1); + free(fb2); + free(fb_result); +} + +static bool +binary_and(bool a, bool b) { + return a & b; +} + +static void +do_test_bit_and(size_t nbits) { + do_test_bit_op(nbits, &binary_and, &fb_bit_and); +} + +TEST_BEGIN(test_bit_and) { +#define NB(nbits) \ + do_test_bit_and(nbits); + NBITS_TAB +#undef NB +} +TEST_END + +static bool +binary_or(bool a, bool b) { + return a | b; +} + +static void +do_test_bit_or(size_t nbits) { + do_test_bit_op(nbits, &binary_or, &fb_bit_or); +} + +TEST_BEGIN(test_bit_or) { +#define NB(nbits) \ + do_test_bit_or(nbits); + NBITS_TAB +#undef NB +} +TEST_END + +static bool +binary_not(bool a, bool b) { + (void)b; + return !a; +} + +static void +fb_bit_not_shim(fb_group_t *dst, fb_group_t *src1, fb_group_t *src2, + size_t nbits) { + (void)src2; + fb_bit_not(dst, src1, nbits); +} + +static void +do_test_bit_not(size_t nbits) { + do_test_bit_op(nbits, &binary_not, &fb_bit_not_shim); +} + +TEST_BEGIN(test_bit_not) { +#define NB(nbits) \ + do_test_bit_not(nbits); + NBITS_TAB +#undef NB +} +TEST_END + int main(void) { return test_no_reentrancy( @@ -820,5 +947,8 @@ main(void) { test_iter_range_exhaustive, test_count_contiguous_simple, test_count_contiguous, - test_count_alternating); + test_count_alternating, + test_bit_and, + test_bit_or, + test_bit_not); }