[llvm] [DWARFLinker][DWARFLinkerParallel][NFC] Refactor DWARFLinker&DWARFLinkerParallel to have a common library. Part 1. (PR #75925)

[Felipe de Azevedo Piovezan via llvm-commits]

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+//===- DWARFLinkerBase.h ----------------------------------------*- 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_DWARFLINKER_DWARFLINKERBASE_H
+#define LLVM_DWARFLINKER_DWARFLINKERBASE_H
+#include "AddressesMap.h"
+#include "DWARFFile.h"
+#include "llvm/ADT/AddressRanges.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/DebugInfo/DWARF/DWARFContext.h"
+#include "llvm/DebugInfo/DWARF/DWARFDebugLine.h"
+#include "llvm/DebugInfo/DWARF/DWARFDebugRangeList.h"
+#include "llvm/DebugInfo/DWARF/DWARFDie.h"
+#include "llvm/DebugInfo/DWARF/DWARFExpression.h"
+#include <map>
+namespace llvm {
+class DWARFUnit;
+
+namespace dwarflinker {
+
+/// The base interface for DWARFLinker implementations.
+class DWARFLinkerBase {
+public:
+  virtual ~DWARFLinkerBase() = default;
+  using MessageHandlerTy = std::function<void(
+      const Twine &Warning, StringRef Context, const DWARFDie *DIE)>;
+  using ObjFileLoaderTy = std::function<ErrorOr<DWARFFile &>(
+      StringRef ContainerName, StringRef Path)>;
+  using InputVerificationHandlerTy =
+      std::function<void(const DWARFFile &File, llvm::StringRef Output)>;
+  using ObjectPrefixMapTy = std::map<std::string, std::string>;
+  using CompileUnitHandlerTy = function_ref<void(const DWARFUnit &Unit)>;
+  using TranslatorFuncTy = std::function<StringRef(StringRef)>;
+  using SwiftInterfacesMapTy = std::map<std::string, std::string>;
+  /// Type of output file.
+  enum class OutputFileType : uint8_t {
+    Object,
+    Assembly,
+  };
+  /// The kind of accelerator tables we should emit.
+  enum class AccelTableKind : uint8_t {
+    Apple,     ///< .apple_names, .apple_namespaces, .apple_types, .apple_objc.
+    Pub,       ///< .debug_pubnames, .debug_pubtypes
+    DebugNames ///< .debug_names.
+  };
+  /// Add object file to be linked. Pre-load compile unit die. Call
+  /// \p OnCUDieLoaded for each compile unit die. If specified \p File
+  /// has reference to the Clang module then such module would be
+  /// pre-loaded by \p Loader for !Update case.
+  ///
+  /// \pre NoODR, Update options should be set before call to addObjectFile.
+  virtual void addObjectFile(
+      DWARFFile &File, ObjFileLoaderTy Loader = nullptr,
+      CompileUnitHandlerTy OnCUDieLoaded = [](const DWARFUnit &) {}) = 0;
+  /// Link debug info for added objFiles. Object files are linked all together.
----------------
felipepiovezan wrote:

>/// Link debug info for added objFiles.

Link the debug info for all object files added through calls to `addObjectFile`?

> Object files are linked all together

This sentence makes it sound like we are linking object files, but we are only linking debug info? IIUC we should remove this entirely

https://github.com/llvm/llvm-project/pull/75925