diff options
| author | Alexander Korotkov | 2021-02-12 14:14:33 +0000 |
|---|---|---|
| committer | Alexander Korotkov | 2021-02-12 14:23:35 +0000 |
| commit | 993bdb9f935a751935a03c80d30857150ba2b645 (patch) | |
| tree | 5744c7b3abd6a42a74abccb574595ff61f251d5e | |
| parent | c8b21b0378141948a2dc0ddde6f57407321787ea (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.
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
| -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 ae978830daf..a86342093eb 100644 --- a/src/include/c.h +++ b/src/include/c.h @@ -133,6 +133,18 @@ #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__ >= 5 +#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 3b94a7388ab..10fc01e1f06 100644 --- a/src/port/pg_crc32c_sse42.c +++ b/src/port/pg_crc32c_sse42.c @@ -18,6 +18,7 @@ #include "port/pg_crc32c.h" +pg_attribute_no_sanitize_alignment() pg_crc32c pg_comp_crc32c_sse42(pg_crc32c crc, const void *data, size_t len) { |