Bug#42733: Type-punning warnings when compiling MySQL --

           strict aliasing violations.

Essentially, the problem is that large parts of the server were
developed in simpler times (last decades, pre C99 standard) when
strict aliasing and compilers supporting such optimizations were
rare to non-existent. Thus, when compiling the server with a modern
compiler that uses strict aliasing rules to perform optimizations,
there are several places in the code that might trigger undefined
behavior.

As evinced by some recent bugs, GCC does a somewhat good of job
misoptimizing such code, but on the other hand also gives warnings
about suspicious code. One problem is that the warnings aren't
always accurate, yet we can't afford to just shut them off as we
might miss real cases. False-positive cases are aggravated mostly
by casts that are likely to trigger undefined behavior.

The solution is to start a cleanup process focused on fixing and
reducing the amount of strict-aliasing related warnings produced
by GCC and others compilers. A good deal of noise reduction can
be achieved by just removing useless casts that are product of
historical cruft and are likely to trigger undefined behavior if
dereferenced.

1 files changed, 11 insertions, 10 deletions

diff --git a/include/sslopt-longopts.h b/include/sslopt-longopts.h
index c76b5dcd252..c038ece1644 100644
--- a/include/sslopt-longopts.h
+++ b/include/sslopt-longopts.h
@@ -16,30 +16,31 @@
 #ifdef HAVE_OPENSSL
 
   {"ssl", OPT_SSL_SSL,
-   "Enable SSL for connection (automatically enabled with other flags). Disable with --skip-ssl.",
- (uchar **) &opt_use_ssl, (uchar **) &opt_use_ssl, 0, GET_BOOL, NO_ARG, 0, 0, 0,
-   0, 0, 0},
+   "Enable SSL for connection (automatically enabled with other flags)."
+   "Disable with --skip-ssl.", &opt_use_ssl, &opt_use_ssl, 0, GET_BOOL,
+   NO_ARG, 0, 0, 0, 0, 0, 0},
   {"ssl-ca", OPT_SSL_CA,
    "CA file in PEM format (check OpenSSL docs, implies --ssl).",
-   (uchar **) &opt_ssl_ca, (uchar **) &opt_ssl_ca, 0, GET_STR, REQUIRED_ARG,
+   &opt_ssl_ca, &opt_ssl_ca, 0, GET_STR, REQUIRED_ARG,
    0, 0, 0, 0, 0, 0},
   {"ssl-capath", OPT_SSL_CAPATH,
    "CA directory (check OpenSSL docs, implies --ssl).",
-   (uchar **) &opt_ssl_capath, (uchar **) &opt_ssl_capath, 0, GET_STR, REQUIRED_ARG,
+   &opt_ssl_capath, &opt_ssl_capath, 0, GET_STR, REQUIRED_ARG,
    0, 0, 0, 0, 0, 0},
   {"ssl-cert", OPT_SSL_CERT, "X509 cert in PEM format (implies --ssl).",
-   (uchar **) &opt_ssl_cert, (uchar **) &opt_ssl_cert, 0, GET_STR, REQUIRED_ARG,
+   &opt_ssl_cert, &opt_ssl_cert, 0, GET_STR, REQUIRED_ARG,
    0, 0, 0, 0, 0, 0},
   {"ssl-cipher", OPT_SSL_CIPHER, "SSL cipher to use (implies --ssl).",
-   (uchar **) &opt_ssl_cipher, (uchar **) &opt_ssl_cipher, 0, GET_STR, REQUIRED_ARG,
+   &opt_ssl_cipher, &opt_ssl_cipher, 0, GET_STR, REQUIRED_ARG,
    0, 0, 0, 0, 0, 0},
   {"ssl-key", OPT_SSL_KEY, "X509 key in PEM format (implies --ssl).",
-   (uchar **) &opt_ssl_key, (uchar **) &opt_ssl_key, 0, GET_STR, REQUIRED_ARG,
+   &opt_ssl_key, &opt_ssl_key, 0, GET_STR, REQUIRED_ARG,
    0, 0, 0, 0, 0, 0},
 #ifdef MYSQL_CLIENT
   {"ssl-verify-server-cert", OPT_SSL_VERIFY_SERVER_CERT,
-   "Verify server's \"Common Name\" in its cert against hostname used when connecting. This option is disabled by default.",
-   (uchar **) &opt_ssl_verify_server_cert, (uchar **) &opt_ssl_verify_server_cert,
+   "Verify server's \"Common Name\" in its cert against hostname used "
+   "when connecting. This option is disabled by default.",
+   &opt_ssl_verify_server_cert, &opt_ssl_verify_server_cert,
     0, GET_BOOL, NO_ARG, 0, 0, 0, 0, 0, 0},
 #endif
 #endif /* HAVE_OPENSSL */