91 lines
3.2 KiB
C++
91 lines
3.2 KiB
C++
//===- lib/MC/MCObjectWriter.cpp - MCObjectWriter implementation ----------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/MC/MCAssembler.h"
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#include "llvm/MC/MCExpr.h"
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#include "llvm/MC/MCObjectWriter.h"
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#include "llvm/MC/MCSymbol.h"
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using namespace llvm;
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MCObjectWriter::~MCObjectWriter() {
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}
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/// Utility function to encode a SLEB128 value.
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void MCObjectWriter::EncodeSLEB128(int64_t Value, raw_ostream &OS) {
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bool More;
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do {
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uint8_t Byte = Value & 0x7f;
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// NOTE: this assumes that this signed shift is an arithmetic right shift.
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Value >>= 7;
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More = !((((Value == 0 ) && ((Byte & 0x40) == 0)) ||
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((Value == -1) && ((Byte & 0x40) != 0))));
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if (More)
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Byte |= 0x80; // Mark this byte that that more bytes will follow.
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OS << char(Byte);
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} while (More);
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}
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/// Utility function to encode a ULEB128 value.
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void MCObjectWriter::EncodeULEB128(uint64_t Value, raw_ostream &OS,
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unsigned Padding) {
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do {
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uint8_t Byte = Value & 0x7f;
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Value >>= 7;
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if (Value != 0 || Padding != 0)
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Byte |= 0x80; // Mark this byte that that more bytes will follow.
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OS << char(Byte);
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} while (Value != 0);
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// Pad with 0x80 and emit a null byte at the end.
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if (Padding != 0) {
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for (; Padding != 1; --Padding)
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OS << '\x80';
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OS << '\x00';
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}
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}
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bool
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MCObjectWriter::IsSymbolRefDifferenceFullyResolved(const MCAssembler &Asm,
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const MCSymbolRefExpr *A,
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const MCSymbolRefExpr *B,
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bool InSet) const {
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// Modified symbol references cannot be resolved.
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if (A->getKind() != MCSymbolRefExpr::VK_None ||
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B->getKind() != MCSymbolRefExpr::VK_None)
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return false;
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const MCSymbol &SA = A->getSymbol();
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const MCSymbol &SB = B->getSymbol();
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if (SA.AliasedSymbol().isUndefined() || SB.AliasedSymbol().isUndefined())
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return false;
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const MCSymbolData &DataA = Asm.getSymbolData(SA);
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const MCSymbolData &DataB = Asm.getSymbolData(SB);
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if(!DataA.getFragment() || !DataB.getFragment())
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return false;
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return IsSymbolRefDifferenceFullyResolvedImpl(Asm, DataA,
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*DataB.getFragment(),
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InSet,
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false);
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}
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bool
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MCObjectWriter::IsSymbolRefDifferenceFullyResolvedImpl(const MCAssembler &Asm,
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const MCSymbolData &DataA,
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const MCFragment &FB,
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bool InSet,
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bool IsPCRel) const {
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const MCSection &SecA = DataA.getSymbol().AliasedSymbol().getSection();
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const MCSection &SecB = FB.getParent()->getSection();
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// On ELF and COFF A - B is absolute if A and B are in the same section.
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return &SecA == &SecB;
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}
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