diff options
| author | Tom Lane <tgl@sss.pgh.pa.us> | 2021-02-13 17:49:08 -0500 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2021-02-13 17:49:08 -0500 |
| commit | cc7ea0717b128cb23d564b9b7c899eb6164752fc (patch) | |
| tree | b67107e2a98652fbf08c5dba0c4033b5fcf382a9 /src | |
| parent | f4d781dae6b60424304b141165943185b907990b (diff) | |
pg_attribute_no_sanitize_alignment() macro
Modern gcc and clang compilers offer alignment sanitizers, which help to detect
pointer misalignment. However, our codebase already contains x86-specific
crc32 computation code, which uses unalignment access. Thankfully, those
compilers also support the attribute, which disables alignment sanitizers at
the function level. This commit adds pg_attribute_no_sanitize_alignment(),
which wraps this attribute, and applies it to pg_comp_crc32c_sse42() function.
Back-patch of commits 993bdb9f9 and ad2ad698a, to enable doing
alignment testing in all supported branches.
Discussion: https://postgr.es/m/CAPpHfdsne3%3DT%3DfMNU45PtxdhSL_J2PjLTeS8rwKnJzUR4YNd4w%40mail.gmail.com
Discussion: https://postgr.es/m/475514.1612745257%40sss.pgh.pa.us
Author: Alexander Korotkov, revised by Tom Lane
Reviewed-by: Tom Lane
Diffstat (limited to 'src')
| -rw-r--r-- | src/include/c.h | 12 | ||||
| -rw-r--r-- | src/port/pg_crc32c_sse42.c | 1 |
2 files changed, 13 insertions, 0 deletions
diff --git a/src/include/c.h b/src/include/c.h index bbd28701347..534fee92300 100644 --- a/src/include/c.h +++ b/src/include/c.h @@ -140,6 +140,18 @@ #endif /* + * Place this macro before functions that should be allowed to make misaligned + * accesses. Think twice before using it on non-x86-specific code! + * Testing can be done with "-fsanitize=alignment -fsanitize-trap=alignment" + * on clang, or "-fsanitize=alignment -fno-sanitize-recover=alignment" on gcc. + */ +#if __clang_major__ >= 7 || __GNUC__ >= 8 +#define pg_attribute_no_sanitize_alignment() __attribute__((no_sanitize("alignment"))) +#else +#define pg_attribute_no_sanitize_alignment() +#endif + +/* * Append PG_USED_FOR_ASSERTS_ONLY to definitions of variables that are only * used in assert-enabled builds, to avoid compiler warnings about unused * variables in assert-disabled builds. diff --git a/src/port/pg_crc32c_sse42.c b/src/port/pg_crc32c_sse42.c index a7f96bb0f8f..7e6780556db 100644 --- a/src/port/pg_crc32c_sse42.c +++ b/src/port/pg_crc32c_sse42.c @@ -18,6 +18,7 @@ #include <nmmintrin.h> +pg_attribute_no_sanitize_alignment() pg_crc32c pg_comp_crc32c_sse42(pg_crc32c crc, const void *data, size_t len) { |