[llvm] annotate interfaces in llvm/CGData and llvm/CodeGen 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/CGData and llvm/CodeGen 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.

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:

• Add LLVM_ABI to a subset of private class methods and fields that require export
• Add LLVM_TEMPLATE_ABI and LLVM_EXPORT_TEMPLATE to exported instantiated templates defined via X-macro
• Add LLVM_ABI_FRIEND to friend member functions declared with LLVM_ABI
• Explicitly make classes non-copyable where needed to due IDS adding LLVM_ABI at the class level
• Add #include "llvm/Support/Compiler.h" to files where it was not auto-added by IDS due to no pre-existing block of include statements.
• Add LLVM_ABI to a small number of symbols that require export but are not declared in headers

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