1//===- lib/MC/MCObjectWriter.cpp - MCObjectWriter implementation ----------===//
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#include "llvm/MC/MCAssembler.h"
11#include "llvm/MC/MCExpr.h"
12#include "llvm/MC/MCObjectWriter.h"
13#include "llvm/MC/MCSymbol.h"
14
15using namespace llvm;
16
17MCObjectWriter::~MCObjectWriter() {
18}
19
20bool
21MCObjectWriter::IsSymbolRefDifferenceFullyResolved(const MCAssembler &Asm,
22                                                   const MCSymbolRefExpr *A,
23                                                   const MCSymbolRefExpr *B,
24                                                   bool InSet) const {
25  // Modified symbol references cannot be resolved.
26  if (A->getKind() != MCSymbolRefExpr::VK_None ||
27      B->getKind() != MCSymbolRefExpr::VK_None)
28    return false;
29
30  const MCSymbol &SA = A->getSymbol();
31  const MCSymbol &SB = B->getSymbol();
32  if (SA.AliasedSymbol().isUndefined() || SB.AliasedSymbol().isUndefined())
33    return false;
34
35  const MCSymbolData &DataA = Asm.getSymbolData(SA);
36  const MCSymbolData &DataB = Asm.getSymbolData(SB);
37  if(!DataA.getFragment() || !DataB.getFragment())
38    return false;
39
40  return IsSymbolRefDifferenceFullyResolvedImpl(Asm, DataA,
41                                                *DataB.getFragment(),
42                                                InSet,
43                                                false);
44}
45
46bool
47MCObjectWriter::IsSymbolRefDifferenceFullyResolvedImpl(const MCAssembler &Asm,
48                                                      const MCSymbolData &DataA,
49                                                      const MCFragment &FB,
50                                                      bool InSet,
51                                                      bool IsPCRel) const {
52  const MCSection &SecA = DataA.getSymbol().AliasedSymbol().getSection();
53  const MCSection &SecB = FB.getParent()->getSection();
54  // On ELF and COFF  A - B is absolute if A and B are in the same section.
55  return &SecA == &SecB;
56}
57