Add -Wimplicit-fallthrough checks if supported

Clang since r369414 (clang-10) can now check -Wimplicit-fallthrough for
C code, and use the GNU C style attribute to denote fallthrough.

Move the test from header only to autoconf. The previous test used
brittle version detection which did not work for newer clang that
supported this feature.

The attribute has to be its own statement, hence the added `;`. It also
can only precede case statements, so the final cases should be
explicitly terminated with break statements.

Fixes commit 3d29d11ac2 ("Clean compilation -Wextra")
Link: 1e0affb6e5
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
This commit is contained in:
Nick Desaulniers
2019-10-29 13:03:41 -07:00
committed by Qi Wang
parent a8b578d538
commit d01b425e5d
8 changed files with 68 additions and 44 deletions

View File

@@ -104,8 +104,8 @@ hash_x86_32(const void *key, int len, uint32_t seed) {
uint32_t k1 = 0;
switch (len & 3) {
case 3: k1 ^= tail[2] << 16; JEMALLOC_FALLTHROUGH
case 2: k1 ^= tail[1] << 8; JEMALLOC_FALLTHROUGH
case 3: k1 ^= tail[2] << 16; JEMALLOC_FALLTHROUGH;
case 2: k1 ^= tail[1] << 8; JEMALLOC_FALLTHROUGH;
case 1: k1 ^= tail[0]; k1 *= c1; k1 = hash_rotl_32(k1, 15);
k1 *= c2; h1 ^= k1;
}
@@ -177,29 +177,29 @@ hash_x86_128(const void *key, const int len, uint32_t seed,
uint32_t k4 = 0;
switch (len & 15) {
case 15: k4 ^= tail[14] << 16; JEMALLOC_FALLTHROUGH
case 14: k4 ^= tail[13] << 8; JEMALLOC_FALLTHROUGH
case 15: k4 ^= tail[14] << 16; JEMALLOC_FALLTHROUGH;
case 14: k4 ^= tail[13] << 8; JEMALLOC_FALLTHROUGH;
case 13: k4 ^= tail[12] << 0;
k4 *= c4; k4 = hash_rotl_32(k4, 18); k4 *= c1; h4 ^= k4;
JEMALLOC_FALLTHROUGH
case 12: k3 ^= tail[11] << 24; JEMALLOC_FALLTHROUGH
case 11: k3 ^= tail[10] << 16; JEMALLOC_FALLTHROUGH
case 10: k3 ^= tail[ 9] << 8; JEMALLOC_FALLTHROUGH
JEMALLOC_FALLTHROUGH;
case 12: k3 ^= tail[11] << 24; JEMALLOC_FALLTHROUGH;
case 11: k3 ^= tail[10] << 16; JEMALLOC_FALLTHROUGH;
case 10: k3 ^= tail[ 9] << 8; JEMALLOC_FALLTHROUGH;
case 9: k3 ^= tail[ 8] << 0;
k3 *= c3; k3 = hash_rotl_32(k3, 17); k3 *= c4; h3 ^= k3;
JEMALLOC_FALLTHROUGH
case 8: k2 ^= tail[ 7] << 24; JEMALLOC_FALLTHROUGH
case 7: k2 ^= tail[ 6] << 16; JEMALLOC_FALLTHROUGH
case 6: k2 ^= tail[ 5] << 8; JEMALLOC_FALLTHROUGH
k3 *= c3; k3 = hash_rotl_32(k3, 17); k3 *= c4; h3 ^= k3;
JEMALLOC_FALLTHROUGH;
case 8: k2 ^= tail[ 7] << 24; JEMALLOC_FALLTHROUGH;
case 7: k2 ^= tail[ 6] << 16; JEMALLOC_FALLTHROUGH;
case 6: k2 ^= tail[ 5] << 8; JEMALLOC_FALLTHROUGH;
case 5: k2 ^= tail[ 4] << 0;
k2 *= c2; k2 = hash_rotl_32(k2, 16); k2 *= c3; h2 ^= k2;
JEMALLOC_FALLTHROUGH
case 4: k1 ^= tail[ 3] << 24; JEMALLOC_FALLTHROUGH
case 3: k1 ^= tail[ 2] << 16; JEMALLOC_FALLTHROUGH
case 2: k1 ^= tail[ 1] << 8; JEMALLOC_FALLTHROUGH
JEMALLOC_FALLTHROUGH;
case 4: k1 ^= tail[ 3] << 24; JEMALLOC_FALLTHROUGH;
case 3: k1 ^= tail[ 2] << 16; JEMALLOC_FALLTHROUGH;
case 2: k1 ^= tail[ 1] << 8; JEMALLOC_FALLTHROUGH;
case 1: k1 ^= tail[ 0] << 0;
k1 *= c1; k1 = hash_rotl_32(k1, 15); k1 *= c2; h1 ^= k1;
JEMALLOC_FALLTHROUGH
break;
}
}
@@ -261,24 +261,25 @@ hash_x64_128(const void *key, const int len, const uint32_t seed,
uint64_t k2 = 0;
switch (len & 15) {
case 15: k2 ^= ((uint64_t)(tail[14])) << 48; JEMALLOC_FALLTHROUGH
case 14: k2 ^= ((uint64_t)(tail[13])) << 40; JEMALLOC_FALLTHROUGH
case 13: k2 ^= ((uint64_t)(tail[12])) << 32; JEMALLOC_FALLTHROUGH
case 12: k2 ^= ((uint64_t)(tail[11])) << 24; JEMALLOC_FALLTHROUGH
case 11: k2 ^= ((uint64_t)(tail[10])) << 16; JEMALLOC_FALLTHROUGH
case 10: k2 ^= ((uint64_t)(tail[ 9])) << 8; JEMALLOC_FALLTHROUGH
case 15: k2 ^= ((uint64_t)(tail[14])) << 48; JEMALLOC_FALLTHROUGH;
case 14: k2 ^= ((uint64_t)(tail[13])) << 40; JEMALLOC_FALLTHROUGH;
case 13: k2 ^= ((uint64_t)(tail[12])) << 32; JEMALLOC_FALLTHROUGH;
case 12: k2 ^= ((uint64_t)(tail[11])) << 24; JEMALLOC_FALLTHROUGH;
case 11: k2 ^= ((uint64_t)(tail[10])) << 16; JEMALLOC_FALLTHROUGH;
case 10: k2 ^= ((uint64_t)(tail[ 9])) << 8; JEMALLOC_FALLTHROUGH;
case 9: k2 ^= ((uint64_t)(tail[ 8])) << 0;
k2 *= c2; k2 = hash_rotl_64(k2, 33); k2 *= c1; h2 ^= k2;
JEMALLOC_FALLTHROUGH
case 8: k1 ^= ((uint64_t)(tail[ 7])) << 56; JEMALLOC_FALLTHROUGH
case 7: k1 ^= ((uint64_t)(tail[ 6])) << 48; JEMALLOC_FALLTHROUGH
case 6: k1 ^= ((uint64_t)(tail[ 5])) << 40; JEMALLOC_FALLTHROUGH
case 5: k1 ^= ((uint64_t)(tail[ 4])) << 32; JEMALLOC_FALLTHROUGH
case 4: k1 ^= ((uint64_t)(tail[ 3])) << 24; JEMALLOC_FALLTHROUGH
case 3: k1 ^= ((uint64_t)(tail[ 2])) << 16; JEMALLOC_FALLTHROUGH
case 2: k1 ^= ((uint64_t)(tail[ 1])) << 8; JEMALLOC_FALLTHROUGH
JEMALLOC_FALLTHROUGH;
case 8: k1 ^= ((uint64_t)(tail[ 7])) << 56; JEMALLOC_FALLTHROUGH;
case 7: k1 ^= ((uint64_t)(tail[ 6])) << 48; JEMALLOC_FALLTHROUGH;
case 6: k1 ^= ((uint64_t)(tail[ 5])) << 40; JEMALLOC_FALLTHROUGH;
case 5: k1 ^= ((uint64_t)(tail[ 4])) << 32; JEMALLOC_FALLTHROUGH;
case 4: k1 ^= ((uint64_t)(tail[ 3])) << 24; JEMALLOC_FALLTHROUGH;
case 3: k1 ^= ((uint64_t)(tail[ 2])) << 16; JEMALLOC_FALLTHROUGH;
case 2: k1 ^= ((uint64_t)(tail[ 1])) << 8; JEMALLOC_FALLTHROUGH;
case 1: k1 ^= ((uint64_t)(tail[ 0])) << 0;
k1 *= c1; k1 = hash_rotl_64(k1, 31); k1 *= c2; h1 ^= k1;
break;
}
}

View File

@@ -40,13 +40,6 @@
#define JEMALLOC_VA_ARGS_HEAD(head, ...) head
#define JEMALLOC_VA_ARGS_TAIL(head, ...) __VA_ARGS__
#if (defined(__GNUC__) || defined(__GNUG__)) && !defined(__clang__) \
&& defined(JEMALLOC_HAVE_ATTR) && (__GNUC__ >= 7)
#define JEMALLOC_FALLTHROUGH JEMALLOC_ATTR(fallthrough);
#else
#define JEMALLOC_FALLTHROUGH /* falls through */
#endif
/* Diagnostic suppression macros */
#if defined(_MSC_VER) && !defined(__clang__)
# define JEMALLOC_DIAGNOSTIC_PUSH __pragma(warning(push))