[llvm] annotate interfaces in llvm/Support for DLL export (#136014)
## Purpose
This patch is one in a series of code-mods that annotate LLVM’s public
interface for export. This patch annotates the `llvm/Support` 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](https://discourse.llvm.org/t/psa-annotating-llvm-public-interface/85307),
and documentation for `LLVM_ABI` and related annotations is found in the
LLVM repo
[here](https://github.com/llvm/llvm-project/blob/main/llvm/docs/InterfaceExportAnnotations.rst).
The bulk of these changes were generated automatically using the
[Interface Definition Scanner (IDS)](https://github.com/compnerd/ids)
tool, followed formatting with `git clang-format`.
The following manual adjustments were also applied after running IDS on
Linux:
- 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 Windows-only code (auto generated with IDS on
Windows)
- Explicitly make classes non-copyable where needed to due IDS adding
`LLVM_ABI` at the class level
- Add `LLVM_TEMPLATE_ABI` and `LLVM_EXPORT_TEMPLATE` to exported
instantiated templates
- Add `LLVM_ABI_FRIEND` to a small number of `friend` function
declarations
- Add `LLVM_ABI` to a subset of private class methods and fields that
require export
- Add `LLVM_ABI` to a small number of symbols that require export but
are not declared in headers
- Add `LLVM_ABI` functions defined via X-macro
## 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