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Make memchr() and memccpy() faster

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Justine Tunney 2024-09-30 05:54:34 -07:00
parent fef24d622a
commit e4d6eb382a
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GPG key ID: BE714B4575D6E328
3 changed files with 95 additions and 24 deletions
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65
test/libc/str/memccpy_test.c
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@ -16,10 +16,18 @@
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/assert.h"
#include "libc/calls/calls.h"
#include "libc/intrin/safemacros.h"
#include "libc/mem/mem.h"
#include "libc/runtime/runtime.h"
#include "libc/runtime/sysconf.h"
#include "libc/stdio/rand.h"
#include "libc/stdio/stdio.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/map.h"
#include "libc/sysv/consts/prot.h"
#include "libc/testlib/benchmark.h"
#include "libc/testlib/ezbench.h"
#include "libc/testlib/testlib.h"
@ -50,6 +58,40 @@ TEST(memccpy, testZeroLength_doesNothing) {
EXPECT_EQ(NULL, memccpy(buf, "hi", '\0', 0));
}
TEST(memccpy, fuzz) {
int pagesz = sysconf(_SC_PAGESIZE);
char *map1 = (char *)mmap(0, pagesz * 2, PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
npassert(map1 != MAP_FAILED);
npassert(!mprotect(map1 + pagesz, pagesz, PROT_NONE));
char *map2 = (char *)mmap(0, pagesz * 2, PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
npassert(map2 != MAP_FAILED);
npassert(!mprotect(map2 + pagesz, pagesz, PROT_NONE));
char *map3 = (char *)mmap(0, pagesz * 2, PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
npassert(map3 != MAP_FAILED);
npassert(!mprotect(map3 + pagesz, pagesz, PROT_NONE));
for (int dsize = 1; dsize < 128; ++dsize) {
char *volatile dst1 = map1 + pagesz - dsize;
char *volatile dst2 = map1 + pagesz - dsize;
for (int i = 0; i < dsize; ++i)
dst1[i] = dst2[i] = rand();
for (int ssize = 1; ssize < dsize * 2; ++ssize) {
char *volatile src = map3 + pagesz - (ssize + 1);
for (int i = 0; i < ssize; ++i)
src[i] = max(rand() & 255, 1);
src[ssize] = 0;
ASSERT_EQ(memccpy_pure(dst1, src, 0, dsize),
memccpy(dst2, src, 0, dsize));
ASSERT_EQ(0, memcmp(dst1, dst2, dsize));
}
}
npassert(!munmap(map3, pagesz * 2));
npassert(!munmap(map2, pagesz * 2));
npassert(!munmap(map1, pagesz * 2));
}
TEST(memccpy, memcpy) {
unsigned n, n1, n2;
char *b1, *b2, *b3, *e1, *e2;
@ -78,3 +120,26 @@ TEST(memccpy, memcpy) {
free(b1);
}
}
#define N 4096
BENCH(memccpy, bench) {
char dst[N];
char src[N + 1];
printf("\n");
for (int n = 1; n <= N; n *= 2) {
for (int i = 0; i < n; ++i)
src[i] = max(rand() & 255, 1);
src[n] = 0;
BENCHMARK(100, n, X(memccpy(dst, src, 0, V(N))));
}
printf("\n");
for (int n = 1; n <= N; n *= 2) {
for (int i = 0; i < n; ++i)
src[i] = max(rand() & 255, 1);
src[n] = 0;
BENCHMARK(100, n, X(memccpy_pure(dst, src, 0, V(N))));
}
}