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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
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| .. | ||
| bench.h | ||
| Build | ||
| epoll-ctl.c | ||
| epoll-wait.c | ||
| futex-hash.c | ||
| futex-lock-pi.c | ||
| futex-requeue.c | ||
| futex-wake-parallel.c | ||
| futex-wake.c | ||
| futex.h | ||
| kallsyms-parse.c | ||
| mem-functions.c | ||
| mem-memcpy-arch.h | ||
| mem-memcpy-x86-64-asm-def.h | ||
| mem-memcpy-x86-64-asm.S | ||
| mem-memcpy-x86-64-lib.c | ||
| mem-memset-arch.h | ||
| mem-memset-x86-64-asm-def.h | ||
| mem-memset-x86-64-asm.S | ||
| numa.c | ||
| sched-messaging.c | ||
| sched-pipe.c | ||
| synthesize.c | ||