Bug 212421 – -Wdeprecated-copy caused by Bitmap copy assignment operator

• Status: RESOLVED
• Resolution: FIXED
• Component: Web Template Framework

[Michael Catanzaro]

Continued from bug #212190, r262030 introduced a warning spam with GCC:

introduced a nice GCC warning spam:

In file included from DerivedSources/JavaScriptCore/unified-sources/UnifiedSource-f0a787a9-2.cpp:5:
/home/mcatanzaro/Projects/WebKit/Source/JavaScriptCore/bytecode/BytecodeLivenessAnalysis.cpp:194:16: warning: implicitly-declared ‘constexpr WTF::Bitmap<4>::Bitmap(const WTF::Bitmap<4>&)’ is deprecated [-Wdeprecated-copy]
  194 |         return result;
      |                ^~~~~~

because:

DerivedSources/ForwardingHeaders/wtf/Bitmap.h:480:13: note: because ‘WTF::Bitmap<4>’ has user-provided ‘void WTF::Bitmap<bitmapSize, WordType>::operator=(const WTF::Bitmap<bitmapSize, WordType>&) [with long unsigned int bitmapSize = 4; WordType = unsigned int]’
  480 | inline void Bitmap<bitmapSize, WordType>::operator=(const Bitmap& other)
      |             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~

To avoid the warning, we should either (a) remove the copy assignment operator, or (b) add a copy constructor. Either way would be fine, but in this case I'd prefer (a) because I don't think the new copy assignment operator is needed. It uses a loop to manually copy the bits of the sole member variable, a std::array, but a default copy of the array should be equivalent (and possibly also a bit faster).

[Michael Catanzaro]

Created attachment 400356 [details]
Patch

[Mark Lam]

Comment on attachment 400356 [details]
Patch

Removal of the assignment operator is not an option.  This was added as a step for upcoming work.  I'll need to take a closer look at what the GCC complaint is and decide what the best solution is.

[Mark Lam]

Comment on attachment 400356 [details]
Patch

I stand corrected.  Michael pointed out on slack that the default assignment operator would take care of the job.  There's no need for my hand written one.

r=me if theAPI test bots are green.

[Mark Lam]

Comment on attachment 400356 [details]
Patch

API bots are green.  Landing this.

[EWS]

Committed r262211: <https://trac.webkit.org/changeset/262211>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 400356 [details].

[Radar WebKit Bug Importer]

<rdar://problem/63687389>