[llvm] annotate interfaces in llvm/DWARFLinker, llvm/DWP, and llvm/Demangle for DLL export

[andrurogerz]

Purpose

This patch is one in a series of code-mods that annotate LLVM’s public interface for export. This patch annotates the llvm/DWARFLinker, llvm/DWP, and llvm/Demangle libraries. These annotations currently have no meaningful impact on the LLVM build; however, they are a prerequisite to support an LLVM Windows DLL (shared library) build.

Background

This effort is tracked in #109483. Additional context is provided in this discourse, and documentation for LLVM_ABI and related annotations is found in the LLVM repo here.

These changes were generated automatically using the Interface Definition Scanner (IDS) tool, followed formatting with git clang-format.

Validation

Local builds and tests to validate cross-platform compatibility. This included llvm, clang, and lldb on the following configurations:

• Windows with MSVC
• Windows with Clang
• Linux with GCC
• Linux with Clang
• Darwin with Clang