llvm-project

04f5198e - [llvm] annotate interfaces in Demangle for DLL export (#147564)

[llvm] annotate interfaces in Demangle for DLL export (#147564) ## Purpose This patch is one in a series of code-mods that annotate LLVM’s public interface for export. This patch annotates the `Demangle` interface with a new `DEMANGLE_ABI` annotation, which behaves like the `LLVM_ABI`. This annotation currently has no meaningful impact on the LLVM build; however, it is a prerequisite to support an LLVM Windows DLL (shared library) build. ## Overview 1. Add a new `Demangle/Visibility.h` header file that defines a new `DEMANGLE_ABI` macro. The macro resolves to the proper DLL export/import annotation on Windows and a "default" visibility annotation elsewhere. 2. Add a new `LLVM_ENABLE_DEMANGLE_EXPORT_ANNOTATIONS ` `#cmakedefine` that is used to gate the definition of `DEMANGLE_ABI`. 3. Code-mod annotate the public `Demangle` interface using the [Interface Definition Scanner (IDS)](https://github.com/compnerd/ids) tool. 4. Manually fix-up `#include` statements for consistency. 5. Format the changes with `clang-format`. 6. Add a "stub" version of `Visibility.h` under `libcxxabi/src/demangle` that always defines `DEMANGLE_ABI` to nothing. 7. Update the canonical `libcxxabi/src/demangle/ItaniumDemangle.h` instead of the llvm copy, and run `cp-to-llvm.sh` to ensure the llvm copy matches. NOTE: we rely on `ccp-to-llvm.sh` not copying `Visibillity.h` as is already the case for `DemangleConfig.h`. ## Background This PR follows the pattern established with the `llvm-c` changes made in #141701. 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). ## 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 --------- Co-authored-by: Louis Dionne <ldionne.2@gmail.com>