On Wed, Sep 23, 2020 at 11:56:46AM +0100, Stefan Hajnoczi wrote:
> clang's C11 atomic_fetch_*() functions only take a C11 atomic type
> pointer argument. QEMU uses direct types (int, etc) and this causes a
> compiler error when a QEMU code calls these functions in a source file
> that also included <stdatomic.h> via a system header file:
>
> $ CC=clang CXX=clang++ ./configure ... && make
> ../util/async.c:79:17: error: address argument to atomic operation must be a pointer to _Atomic type ('unsigned int *' invalid)
>
> Avoid using atomic_*() names in QEMU's atomic.h since that namespace is
> used by <stdatomic.h>. Prefix QEMU's APIs with 'q' so that atomic.h
> and <stdatomic.h> can co-exist. I checked /usr/include on my machine and
> searched GitHub for existing "qatomic_" users but there seem to be none.
>
> This patch was generated using:
>
> $ git grep -h -o '\<atomic\(64\)\?_[a-z0-9_]\+' include/qemu/atomic.h | \
> sort -u >/tmp/changed_identifiers
> $ for identifier in $(</tmp/changed_identifiers); do
> sed -i "s%\<$identifier\>%q$identifier%g" \
> $(git grep -I -l "\<$identifier\>")
> done
>
> I manually fixed line-wrap issues and misaligned rST tables.
>
> Signed-off-by: Stefan Hajnoczi <stefanha@xxxxxxxxxx>
> ---
> v3:
> * Use qatomic_ instead of atomic_ [Paolo]
> * The diff of my manual fixups is available here:
> https://vmsplice.net/~stefan/atomic-namespace-pre-fixups-v3.diff
> - Dropping #ifndef qatomic_fetch_add in atomic.h
> - atomic_##X(haddr, val) glue macros not caught by grep
> - Keep atomic_add-bench name
> - C preprocessor backslash-newline ('\') column alignment
> - Line wrapping
Thanks, applied quickly due to high risk of conflicts:
https://github.com/stefanha/qemu/commits/block
Stefan
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