third_party/llvm-7.0/llvm/lib/MC/MCObjectWriter.cpp

//===- lib/MC/MCObjectWriter.cpp - MCObjectWriter implementation ----------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#include "llvm/MC/MCObjectWriter.h"
#include "llvm/MC/MCAssembler.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCFragment.h"
#include "llvm/MC/MCSymbol.h"

using namespace llvm;

MCObjectWriter::~MCObjectWriter() = default;

bool MCObjectWriter::isSymbolRefDifferenceFullyResolved(
    const MCAssembler &Asm, const MCSymbolRefExpr *A, const MCSymbolRefExpr *B,
    bool InSet) const {
  // Modified symbol references cannot be resolved.
  if (A->getKind() != MCSymbolRefExpr::VK_None ||
      B->getKind() != MCSymbolRefExpr::VK_None)
    return false;

  const MCSymbol &SA = A->getSymbol();
  const MCSymbol &SB = B->getSymbol();
  if (SA.isUndefined() || SB.isUndefined())
    return false;

  if (!SA.getFragment() || !SB.getFragment())
    return false;

  return isSymbolRefDifferenceFullyResolvedImpl(Asm, SA, SB, InSet);
}

bool MCObjectWriter::isSymbolRefDifferenceFullyResolvedImpl(
    const MCAssembler &Asm, const MCSymbol &A, const MCSymbol &B,
    bool InSet) const {
  return isSymbolRefDifferenceFullyResolvedImpl(Asm, A, *B.getFragment(), InSet,
                                                false);
}

bool MCObjectWriter::isSymbolRefDifferenceFullyResolvedImpl(
    const MCAssembler &Asm, const MCSymbol &SymA, const MCFragment &FB,
    bool InSet, bool IsPCRel) const {
  const MCSection &SecA = SymA.getSection();
  const MCSection &SecB = *FB.getParent();
  // On ELF and COFF  A - B is absolute if A and B are in the same section.
  return &SecA == &SecB;
}