The "extensible_" prefix on these files was inherited from LLVM, where it
distinguished the dynamic RTTI APIs from the LLVM's custom static RTTI APIs.
In the ORC runtime these files will be used to hold all of our RTTI APIs
(the current dynamic ones, and any static ones added in the future), so we
shouldn't use this prefix.
We should use `orc_rt` as the public C++ API namespace for the ORC runtime and
control symbol visibility to hide implementation details, rather than rely on
the '__' prefix.
Initial platform support for COFF/x86_64.
Completed features:
* Statically linked orc runtime.
* Full linking/initialization of static/dynamic vc runtimes and microsoft stl libraries.
* SEH exception handling.
* Full static initializers support
* dlfns
* JIT side symbol lookup/dispatch
Things to note:
* It uses vc runtime libraries found in vc toolchain installations.
* Bootstrapping state is separated because when statically linking orc runtime it needs microsoft stl functions to initialize the orc runtime, but static initializers need to be ran in order to fully initialize stl libraries.
* Process symbols can't be used blidnly on msvc platform; otherwise duplicate definition error gets generated. If process symbols are used, it's destined to get out-of-reach error at some point.
* Atexit currently not handled -- will be handled in the follow-up patches.
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D130479
These will be used for error propagation and handling in the ORC runtime.
The implementations of these types are cut-down versions of the error
support in llvm/Support/Error.h. Most advice on llvm::Error and llvm::Expected
(e.g. from the LLVM Programmer's manual) applies equally to __orc_rt::Error
and __orc_rt::Expected. The primary difference is the mechanism for testing
and handling error types: The ORC runtime uses a new 'error_cast' operation
to replace the handleErrors family of functions. See error_cast comments in
error.h.
