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author | Gustavo A. R. Silva <gustavoars@kernel.org> | 2020-05-07 14:00:52 -0500 |
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committer | Thomas Bogendoerfer <tsbogend@alpha.franken.de> | 2020-05-08 12:01:02 +0200 |
commit | c4ad6ea9574bfa29ca00ddf6b6b1508ec344ff45 (patch) | |
tree | d4cba20f65b10ec2996b3d7504300314ffe7892a /arch/mips/Makefile | |
parent | 68fbb9721ea76b2a3088b749e004456f2de05b9f (diff) | |
download | linux-c4ad6ea9574bfa29ca00ddf6b6b1508ec344ff45.tar.bz2 |
MIPS: Replace zero-length array with flexible-array
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Diffstat (limited to 'arch/mips/Makefile')
0 files changed, 0 insertions, 0 deletions