[llvm] annotate interfaces in llvm/SandboxIR 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/SandboxIR library. 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.

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

The following manual adjustments were also applied after running IDS on Linux:

• Replicate the #if defined(_MSC_VER) && !defined(__clang__) guard in Constant.h that was already used for the corresponding declarations in Constant.cpp.
• Explicitly #include "llvm/SandboxIR/Value.h" in Tracker.h so that the symbol is available for exported templates in this file. These templates get fully instantiated on DLL export, so they require the full definition of Value.
• Add extern template instantiation declarations for GlobalWithNodeAPI template types in Constants.h and annotate them with LLVM_TEMPLATE_ABI.
• Add LLVM_EXPORT_TEMPLATE to GlobalWithNodeAPI template instantiations in Constants.cpp.

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