1 //===- Core/SharedLibraryAtom.h - A Shared Library Atom -------------------===//
2 //
3 //                             The LLVM Linker
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 LLD_CORE_SHARED_LIBRARY_ATOM_H
11 #define LLD_CORE_SHARED_LIBRARY_ATOM_H
12 
13 #include "lld/Core/Atom.h"
14 
15 namespace lld {
16 
17 /// A SharedLibraryAtom has no content.
18 /// It exists to represent a symbol which will be bound at runtime.
19 class SharedLibraryAtom : public Atom {
20 public:
21   enum class Type : uint32_t {
22     Unknown,
23     Code,
24     Data,
25   };
26 
27   /// Returns shared library name used to load it at runtime.
28   /// On Darwin it is the LC_DYLIB_LOAD dylib name.
29   virtual StringRef loadName() const = 0;
30 
31   /// Returns if shared library symbol can be missing at runtime and if
32   /// so the loader should silently resolve address of symbol to be nullptr.
33   virtual bool canBeNullAtRuntime() const = 0;
34 
35   virtual Type type() const = 0;
36 
37   virtual uint64_t size() const = 0;
38 
classof(const Atom * a)39   static bool classof(const Atom *a) {
40     return a->definition() == definitionSharedLibrary;
41   }
42 
classof(const SharedLibraryAtom *)43   static inline bool classof(const SharedLibraryAtom *) { return true; }
44 
45 protected:
SharedLibraryAtom()46   SharedLibraryAtom() : Atom(definitionSharedLibrary) {}
47 
48   ~SharedLibraryAtom() override = default;
49 };
50 
51 } // namespace lld
52 
53 #endif // LLD_CORE_SHARED_LIBRARY_ATOM_H
54