1 //===-- WebAssemblyELFObjectWriter.cpp - WebAssembly ELF Writer -----------===//
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 /// \file
11 /// \brief This file handles ELF-specific object emission, converting LLVM's
12 /// internal fixups into the appropriate relocations.
13 ///
14 //===----------------------------------------------------------------------===//
15 
16 #include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
17 #include "llvm/MC/MCELFObjectWriter.h"
18 #include "llvm/MC/MCFixup.h"
19 #include "llvm/Support/ErrorHandling.h"
20 using namespace llvm;
21 
22 namespace {
23 class WebAssemblyELFObjectWriter final : public MCELFObjectTargetWriter {
24 public:
25   WebAssemblyELFObjectWriter(bool Is64Bit, uint8_t OSABI);
26 
27 protected:
28   unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup,
29                         bool IsPCRel) const override;
30 };
31 } // end anonymous namespace
32 
33 // FIXME: Use EM_NONE as a temporary hack. Should we decide to pursue ELF
34 // writing seriously, we should email generic-abi@googlegroups.com and ask
35 // for our own ELF code.
WebAssemblyELFObjectWriter(bool Is64Bit,uint8_t OSABI)36 WebAssemblyELFObjectWriter::WebAssemblyELFObjectWriter(bool Is64Bit,
37                                                        uint8_t OSABI)
38     : MCELFObjectTargetWriter(Is64Bit, OSABI, ELF::EM_NONE,
39                               /*HasRelocationAddend=*/true) {}
40 
GetRelocType(const MCValue & Target,const MCFixup & Fixup,bool IsPCRel) const41 unsigned WebAssemblyELFObjectWriter::GetRelocType(const MCValue &Target,
42                                                   const MCFixup &Fixup,
43                                                   bool IsPCRel) const {
44   // FIXME: Do we need our own relocs?
45   return Fixup.getKind();
46 }
47 
createWebAssemblyELFObjectWriter(raw_pwrite_stream & OS,bool Is64Bit,uint8_t OSABI)48 MCObjectWriter *llvm::createWebAssemblyELFObjectWriter(raw_pwrite_stream &OS,
49                                                        bool Is64Bit,
50                                                        uint8_t OSABI) {
51   MCELFObjectTargetWriter *MOTW =
52       new WebAssemblyELFObjectWriter(Is64Bit, OSABI);
53   return createELFObjectWriter(MOTW, OS, /*IsLittleEndian=*/true);
54 }
55