Bug 113308 – Support C++11 static_assert

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

[Allan Sandfeld Jensen]

When available we use the Clang extension _Static_assert for compile assertion since this is just a C version of the C++11 static assert we should use the C++11 version when possible.

Note this is not always possible since Assertions.h where COMPILE_ASSERT is defined can be used from both C and C++, and COMPILE_ASSERT will therefore still not be available in C for non clang compilers.

[Allan Sandfeld Jensen]

Created attachment 195083 [details]
Patch

[Alexey Proskuryakov]

Comment on attachment 195083 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=195083&action=review

> Source/WTF/wtf/Assertions.h:348
>  #if COMPILER_SUPPORTS(C_STATIC_ASSERT)
>  #define COMPILE_ASSERT(exp, name) _Static_assert((exp), #name)

I think that this should have a comment explaining why we still have this:

// Unlike static_assert below, this also works in plain C code.

That said, I'm unsure if we ever use - or want to use - COMPILE_ASSERT in plain C code.

> Source/WTF/wtf/Compiler.h:128
> +#define WTF_COMPILER_SUPPORTS_CXX_STATIC_ASSERT 1

Shouldn't this be defined for clang too? The behavior in this patch would not be affected, but it's better to not leave such a tripmine for later IMO.

[Allan Sandfeld Jensen]

Created attachment 195266 [details]
Patch

Added detection of C++11 static_assert to clang, and C11 _Static_assert to GCC.

[Allan Sandfeld Jensen]

Created attachment 195267 [details]
Patch

Remove accidentially uploaded change.

[Allan Sandfeld Jensen]

Comment on attachment 195267 [details]
Patch

Clearing flags on attachment: 195267

Committed r146993: <http://trac.webkit.org/changeset/146993>

[Allan Sandfeld Jensen]

All reviewed patches have been landed.  Closing bug.