1 //===- Thunks.h --------------------------------------------------------===//
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #ifndef LLD_ELF_THUNKS_H
11 #define LLD_ELF_THUNKS_H
13 #include "Relocations.h"
18 template <class ELFT> class InputSection;
20 // Class to describe an instance of a Thunk.
21 // A Thunk is a code-sequence inserted by the linker in between a caller and
22 // the callee. The relocation to the callee is redirected to the Thunk, which
23 // after executing transfers control to the callee. Typical uses of Thunks
24 // include transferring control from non-pi to pi and changing state on
27 // Thunks can be created for DefinedRegular and Shared Symbols. The Thunk
28 // is stored in a field of the Symbol Destination.
29 // Thunks to be written to an InputSection are recorded by the InputSection.
30 template <class ELFT> class Thunk {
31 typedef typename ELFT::uint uintX_t;
34 Thunk(const SymbolBody &Destination, const InputSection<ELFT> &Owner);
37 virtual uint32_t size() const { return 0; }
38 virtual void writeTo(uint8_t *Buf) const {}
39 uintX_t getVA() const;
42 const SymbolBody &Destination;
43 const InputSection<ELFT> &Owner;
47 // For a Relocation to symbol S from InputSection Src, create a Thunk and
48 // update the fields of S and the InputSection that the Thunk body will be
49 // written to. At present there are implementations for ARM and Mips Thunks.
51 void addThunk(uint32_t RelocType, SymbolBody &S, InputSection<ELFT> &Src);