Bug 180600 – bmalloc StaticMutex's constructor should be constexpr

• Status: RESOLVED
• Resolution: FIXED
• Component: New Bugs

[Yusuke Suzuki]

bmalloc StaticMutex's constructor should be constexpr

[Yusuke Suzuki]

Created attachment 328854 [details]
Patch

[Yusuke Suzuki]

Created attachment 328855 [details]
Patch

[Yusuke Suzuki]

Comment on attachment 328855 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=328855&action=review

> Source/bmalloc/bmalloc/StaticMutex.h:50
> +    std::atomic_flag m_isSpinning = ATOMIC_FLAG_INIT;

hmm, it is not constexpr (according to the spec). Maybe, we cannot use std::atomic_flag { ATOMIC_FLAG_INIT } since this form is not described in the spec. And even if we use { ATOMIC_FLAG_INIT }, it is still not constexpr.
Note that std::atomic<bool> has a constexpr constructor.

[JF Bastien]

(In reply to Yusuke Suzuki from comment #3)
> Comment on attachment 328855 [details]
> Patch
> 
> View in context:
> https://bugs.webkit.org/attachment.cgi?id=328855&action=review
> 
> > Source/bmalloc/bmalloc/StaticMutex.h:50
> > +    std::atomic_flag m_isSpinning = ATOMIC_FLAG_INIT;
> 
> hmm, it is not constexpr (according to the spec). Maybe, we cannot use
> std::atomic_flag { ATOMIC_FLAG_INIT } since this form is not described in
> the spec. And even if we use { ATOMIC_FLAG_INIT }, it is still not constexpr.
> Note that std::atomic<bool> has a constexpr constructor.

The one thing atomic<bool> doesn't have in theory is guaranteed lock-free... but in practice it does. Otherwise it's more capable in every way than atomic_flag (until we improve atomic_flag for C++20).

So yeah atomic<bool> is better :-)

[Yusuke Suzuki]

Comment on attachment 328855 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=328855&action=review

>>> Source/bmalloc/bmalloc/StaticMutex.h:50
>>> +    std::atomic_flag m_isSpinning = ATOMIC_FLAG_INIT;
>> 
>> hmm, it is not constexpr (according to the spec). Maybe, we cannot use std::atomic_flag { ATOMIC_FLAG_INIT } since this form is not described in the spec. And even if we use { ATOMIC_FLAG_INIT }, it is still not constexpr.
>> Note that std::atomic<bool> has a constexpr constructor.
> 
> The one thing atomic<bool> doesn't have in theory is guaranteed lock-free... but in practice it does. Otherwise it's more capable in every way than atomic_flag (until we improve atomic_flag for C++20).
> 
> So yeah atomic<bool> is better :-)

OK, I'll change it to std::atomic<bool>

[Yusuke Suzuki]

Created attachment 337265 [details]
Patch

[EWS Watchlist]

Attachment 337265 [details] did not pass style-queue:


ERROR: Source/bmalloc/bmalloc/Mutex.cpp:27:  Found header this file implements before WebCore config.h. Should be: config.h, primary header, blank line, and then alphabetically sorted.  [build/include_order] [4]
ERROR: Source/bmalloc/bmalloc/Mutex.cpp:42:  More than one command on the same line  [whitespace/newline] [4]
ERROR: Source/bmalloc/bmalloc/Mutex.h:43:  try_lock is incorrectly named. Don't use underscores in your identifier names.  [readability/naming/underscores] [4]
ERROR: Source/bmalloc/bmalloc/Mutex.h:74:  Mutex::try_lock is incorrectly named. Don't use underscores in your identifier names.  [readability/naming/underscores] [4]
Total errors found: 4 in 38 files


If any of these errors are false positives, please file a bug against check-webkit-style.

[Yusuke Suzuki]

Created attachment 337266 [details]
Patch

[Yusuke Suzuki]

Created attachment 337270 [details]
Patch

[EWS Watchlist]

Attachment 337270 [details] did not pass style-queue:


ERROR: Source/bmalloc/bmalloc/Mutex.cpp:27:  Found header this file implements before WebCore config.h. Should be: config.h, primary header, blank line, and then alphabetically sorted.  [build/include_order] [4]
ERROR: Source/bmalloc/bmalloc/Mutex.cpp:42:  More than one command on the same line  [whitespace/newline] [4]
ERROR: Source/bmalloc/bmalloc/Mutex.h:43:  try_lock is incorrectly named. Don't use underscores in your identifier names.  [readability/naming/underscores] [4]
ERROR: Source/bmalloc/bmalloc/Mutex.h:74:  Mutex::try_lock is incorrectly named. Don't use underscores in your identifier names.  [readability/naming/underscores] [4]
Total errors found: 4 in 38 files


If any of these errors are false positives, please file a bug against check-webkit-style.

[Mark Lam]

Comment on attachment 337270 [details]
Patch

r=me

[Yusuke Suzuki]

Comment on attachment 337270 [details]
Patch

Thank you!

[WebKit Commit Bot]

Comment on attachment 337270 [details]
Patch

Clearing flags on attachment: 337270

Committed r230308: <https://trac.webkit.org/changeset/230308>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.

[Radar WebKit Bug Importer]

<rdar://problem/39212969>