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Commit993bdb9

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pg_attribute_no_sanitize_alignment() macro
Modern gcc and clang compilers offer alignment sanitizers, which help to detectpointer misalignment. However, our codebase already contains x86-specificcrc32 computation code, which uses unalignment access. Thankfully, thosecompilers also support the attribute, which disables alignment sanitizers atthe 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.comDiscussion:https://postgr.es/m/475514.1612745257%40sss.pgh.pa.usAuthor: Alexander Korotkov, revised by Tom LaneReviewed-by: Tom Lane
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‎src/include/c.h

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#definepg_nodiscard
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#endif
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/*
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* Place this macro before functions that should be allowed to make misaligned
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* accesses. Think twice before using it on non-x86-specific code!
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* Testing can be done with "-fsanitize=alignment -fsanitize-trap=alignment"
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* on clang, or "-fsanitize=alignment -fno-sanitize-recover=alignment" on gcc.
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*/
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#if__clang_major__ >=7||__GNUC__ >=5
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#definepg_attribute_no_sanitize_alignment() __attribute__((no_sanitize("alignment")))
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#else
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#definepg_attribute_no_sanitize_alignment()
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#endif
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/*
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* Append PG_USED_FOR_ASSERTS_ONLY to definitions of variables that are only
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* used in assert-enabled builds, to avoid compiler warnings about unused

‎src/port/pg_crc32c_sse42.c

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#include"port/pg_crc32c.h"
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pg_attribute_no_sanitize_alignment()
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pg_crc32c
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pg_comp_crc32c_sse42(pg_crc32ccrc,constvoid*data,size_tlen)
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{

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