Andrew Rogers 0580563299
[llvm] annotate interfaces in llvm-c for DLL export (#141701)
## Purpose

This patch is one in a series of code-mods that annotate LLVM’s public
interface for export. This patch annotates the `llvm-c` interface with a
new `LLVM_C_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 `llvm-c/Visibility.h` header file that defines a new
`LLVM_C_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_LLVM_C_EXPORT_ANNOTATIONS` `#cmakedefine` that
is used to gate the definition of `LLVM_C_ABI`.
3. Remove the existing `LLVM_C_ABI` definition from
`llvm/Support/Compiler.h`. Update the small number of `LLVM_C_ABI`
references to get it from the new `llvm-c/Visibility.h` header.
4. Code-mod annotate the public `llvm-c` interface using the [Interface
Definition Scanner (IDS)](https://github.com/compnerd/ids) tool.
5. Format the changes with `clang-format`.

## 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).

## 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
2025-07-08 08:50:21 -07:00

86 lines
2.8 KiB
C++

/*===-- llvm-c/Comdat.h - Module Comdat C Interface -------------*- C++ -*-===*\
|* *|
|* Part of the LLVM Project, under the Apache License v2.0 with LLVM *|
|* Exceptions. *|
|* See https://llvm.org/LICENSE.txt for license information. *|
|* SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception *|
|* *|
|*===----------------------------------------------------------------------===*|
|* *|
|* This file defines the C interface to COMDAT. *|
|* *|
\*===----------------------------------------------------------------------===*/
#ifndef LLVM_C_COMDAT_H
#define LLVM_C_COMDAT_H
#include "llvm-c/ExternC.h"
#include "llvm-c/Types.h"
#include "llvm-c/Visibility.h"
LLVM_C_EXTERN_C_BEGIN
/**
* @defgroup LLVMCCoreComdat Comdats
* @ingroup LLVMCCore
*
* @{
*/
typedef enum {
LLVMAnyComdatSelectionKind, ///< The linker may choose any COMDAT.
LLVMExactMatchComdatSelectionKind, ///< The data referenced by the COMDAT must
///< be the same.
LLVMLargestComdatSelectionKind, ///< The linker will choose the largest
///< COMDAT.
LLVMNoDeduplicateComdatSelectionKind, ///< No deduplication is performed.
LLVMSameSizeComdatSelectionKind ///< The data referenced by the COMDAT must be
///< the same size.
} LLVMComdatSelectionKind;
/**
* Return the Comdat in the module with the specified name. It is created
* if it didn't already exist.
*
* @see llvm::Module::getOrInsertComdat()
*/
LLVM_C_ABI LLVMComdatRef LLVMGetOrInsertComdat(LLVMModuleRef M,
const char *Name);
/**
* Get the Comdat assigned to the given global object.
*
* @see llvm::GlobalObject::getComdat()
*/
LLVM_C_ABI LLVMComdatRef LLVMGetComdat(LLVMValueRef V);
/**
* Assign the Comdat to the given global object.
*
* @see llvm::GlobalObject::setComdat()
*/
LLVM_C_ABI void LLVMSetComdat(LLVMValueRef V, LLVMComdatRef C);
/*
* Get the conflict resolution selection kind for the Comdat.
*
* @see llvm::Comdat::getSelectionKind()
*/
LLVM_C_ABI LLVMComdatSelectionKind LLVMGetComdatSelectionKind(LLVMComdatRef C);
/*
* Set the conflict resolution selection kind for the Comdat.
*
* @see llvm::Comdat::setSelectionKind()
*/
LLVM_C_ABI void LLVMSetComdatSelectionKind(LLVMComdatRef C,
LLVMComdatSelectionKind Kind);
/**
* @}
*/
LLVM_C_EXTERN_C_END
#endif