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Date: Wed, 17 Jul 2019 14:42:34 +0100
From: John Levon <levon@movementarian.org>
Subject: Packed struct size issue
Message-ID: <20190717134234.GA5551@movementarian.org>
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Cc: andy@omniosce.org


Andy Fiddaman discovered:

$ cat ./test.c
#include <stdio.h>
#include <stdint.h>

struct t1 {
        uint8_t                 critical_warning;
        uint16_t                temperature;
        uint8_t                 available_spare;
} __packed;

_Static_assert(sizeof(struct t1) == 4, "bad size for t1");

struct t2 {
        uint8_t                 critical_warning;
        uint16_t                temperature;
        uint8_t                 available_spare;
};

_Static_assert(sizeof(struct t2) == 6, "bad size for t2");

$ ./smatch ./test.c
./test.c:10:34: error: static assertion failed: "bad size for t1"


Looks like we lost this commit:
https://github.com/illumos/smatch/commit/0c60237e4096b7576f0aec21a7545026c7041611#diff-0cd054d23ed9e02274eaa540fc7e6536

??

This works:

https://github.com/citrus-it/illumos-omnios/commit/88e29e1705a616695ec6f905c3cab1f600e12659?diff=unified

regards
john