1//===- Linker.h - Module Linker Interface -----------------------*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef LLVM_LINKER_LINKER_H
11#define LLVM_LINKER_LINKER_H
12
13#include "llvm/IR/FunctionInfo.h"
14#include "llvm/Linker/IRMover.h"
15
16namespace llvm {
17class Module;
18class StructType;
19class Type;
20
21/// This class provides the core functionality of linking in LLVM. It keeps a
22/// pointer to the merged module so far. It doesn't take ownership of the
23/// module since it is assumed that the user of this class will want to do
24/// something with it after the linking.
25class Linker {
26  IRMover Mover;
27
28public:
29  enum Flags {
30    None = 0,
31    OverrideFromSrc = (1 << 0),
32    LinkOnlyNeeded = (1 << 1),
33    InternalizeLinkedSymbols = (1 << 2)
34  };
35
36  Linker(Module &M);
37
38  /// \brief Link \p Src into the composite.
39  ///
40  /// Passing OverrideSymbols as true will have symbols from Src
41  /// shadow those in the Dest.
42  /// For ThinLTO function importing/exporting the \p FunctionInfoIndex
43  /// is passed. If \p FunctionsToImport is provided, only the functions that
44  /// are part of the set will be imported from the source module.
45  /// The \p ValIDToTempMDMap is populated by the linker when function
46  /// importing is performed.
47  ///
48  /// Returns true on error.
49  bool linkInModule(std::unique_ptr<Module> Src, unsigned Flags = Flags::None,
50                    const FunctionInfoIndex *Index = nullptr,
51                    DenseSet<const GlobalValue *> *FunctionsToImport = nullptr,
52                    DenseMap<unsigned, MDNode *> *ValIDToTempMDMap = nullptr);
53
54  /// This exists to implement the deprecated LLVMLinkModules C api. Don't use
55  /// for anything else.
56  bool linkInModuleForCAPI(Module &Src);
57
58  static bool linkModules(Module &Dest, std::unique_ptr<Module> Src,
59                          unsigned Flags = Flags::None);
60
61  /// \brief Link metadata from \p Src into the composite. The source is
62  /// destroyed.
63  ///
64  /// The \p ValIDToTempMDMap sound have been populated earlier during function
65  /// importing from \p Src.
66  bool linkInMetadata(Module &Src,
67                      DenseMap<unsigned, MDNode *> *ValIDToTempMDMap);
68};
69
70/// Create a new module with exported local functions renamed and promoted
71/// for ThinLTO.
72std::unique_ptr<Module> renameModuleForThinLTO(std::unique_ptr<Module> M,
73                                               const FunctionInfoIndex *Index);
74
75} // End llvm namespace
76
77#endif
78