C/C++: Add -Waddress-of-packed-memberhjl/pr51628/master

When address of packed member of struct or union is taken, it may result
in an unaligned pointer value.  This patch adds -Waddress-of-packed-member
to warn it:

$ cat x.i
struct pair_t
{
  char c;
  int i;
} __attribute__ ((packed));

extern struct pair_t p;
int *addr = &p.i;
$ gcc -O2 -S x.i
x.i:8:13: warning: initialization of 'int *' from address of packed member of 'struct pair_t' may result in an unaligned pointer value [-Waddress-of-packed-member]
 int *addr = &p.i;
             ^
$

This warning is enabled by default.

gcc/c/

	PR c/51628
	* doc/invoke.texi: Document -Wno-address-of-packed-member.

gcc/c-family/

	PR c/51628
	* c-common.h (warn_for_address_of_packed_member): New.
	* c-warn.c (warn_for_address_of_packed_member): New function.
	* c.opt: Add -Wno-address-of-packed-member.

gcc/c/

	PR c/51628
	* c-typeck.c (convert_for_assignment): Call
	warn_for_address_of_packed_member.  Issue an warning if address
	of packed member is taken.

gcc/cp/

	PR c/51628
	* call.c (convert_for_arg_passing): Call
	warn_for_address_of_packed_member.  Issue an warning if address
	of packed member is taken.
	* typeck.c (convert_for_assignment): Likewise.

gcc/testsuite/

	PR c/51628
	* c-c++-common/pr51628-1.c: New tests.
	* c-c++-common/pr51628-10.c: Likewise.
	* c-c++-common/pr51628-2.c: Likewise.
	* c-c++-common/pr51628-3.c: Likewise.
	* c-c++-common/pr51628-4.c: Likewise.
	* c-c++-common/pr51628-5.c: Likewise.
	* c-c++-common/pr51628-6.c: Likewise.
	* c-c++-common/pr51628-7.c: Likewise.
	* c-c++-common/pr51628-8.c: Likewise.
	* c-c++-common/pr51628-9.c: Likewise.
	* gcc.dg/pr51628-10.c: Likewise.
	* gcc.dg/pr51628-11.c: Likewise.
	* c-c++-common/ubsan/align-10.c: Add -Wno-address-of-packed-member.
	* c-c++-common/ubsan/align-2.c: Likewise.
	* c-c++-common/ubsan/align-4.c: Likewise.
	* c-c++-common/ubsan/align-6.c: Likewise.
	* c-c++-common/ubsan/align-7.c: Likewise.
	* c-c++-common/ubsan/align-8.c: Likewise.
	* g++.dg/ubsan/align-2.C: Likewise.
	* gcc.target/i386/avx512bw-vmovdqu16-2.c: Likewise.
	* gcc.target/i386/avx512f-vmovdqu32-2.c: Likewise.
	* gcc.target/i386/avx512f-vmovdqu64-2.c: Likewise.
	* gcc.target/i386/avx512vl-vmovdqu16-2.c: Likewise.
	* gcc.target/i386/avx512vl-vmovdqu32-2.c: Likewise.
	* gcc.target/i386/avx512vl-vmovdqu64-2.c: Likewise.

0 files changed, 0 insertions, 0 deletions