core.stdcpp: Upstream differences between dmd and gdc/ldc druntimes

[ibuclaw]

Upstreamed:

• Change destructors from extern(D) -> @weak extern(C++)
• Change CppRuntime_Microsoft exception.what from extern(D) -> @weak extern(C++)
• Add assert(0) to CppRuntime_Microsoft exception._Doraise
• Add missing bad_exception.what for GenericBaseException
• Add @nogc: to core.stdcpp.typeinfo
• Add nothrow to type_info.before and type_info.name
• Mark CppRuntime_Gcc type_info as abstract
• Add definitions to CppRuntime_Gcc and CppRuntime_Clang bad_cast.what and bad_typeid.what

New: Things found to be broken just by adding tests. (Moved to other PRs).

• Change CppRuntme_Gcc __class_type_info from class -> extern(C++, class) struct
• Add implementation of typeinfo for CppRuntime_Clang
• Fix the alignment of _Unwind_Exception to fix catching exceptions using dwarfeh on x86
• Add separate implemention of exception for CppRuntime_DigitalMars

[dlang-bot]

Thanks for your pull request, @ibuclaw!

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Testing this PR locally

If you don't have a local development environment setup, you can use Digger to test this PR:

dub run digger -- build "master + druntime#3552"

[ibuclaw]

Added tests that pass with GDC.

[ibuclaw]

Commented out typeinfo tests because of missing CppRuntime_Clang bindings.

Edit: Added version block for CppRuntime_Clang.

[ibuclaw]

DMD's _Unwind_Exception is not aligned correctly on x86. It's a shame there isn't an __aligned__ keyword to mean the biggest alignment that any data type can require.

[Geod24]

Nice! With those, will things still be tied to the CppRuntime_ druntime was compiled with ?

[ibuclaw]

Nice! With those, will things still be tied to the CppRuntime_ druntime was compiled with ?

Yes, though IIUC Clang and GCC are compatible? Probably the only two we care about in terms of movability because Microsoft doesn't use the Itanium ABI.