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llvm-mirror/lib/MC/MCSectionCOFF.cpp
Martin Storsjo 038e6fd8e4 [COFF] Fix assembly output of comdat sections without an attached symbol
Since SVN r335286, the .xdata sections are produced without an attached
symbol, which requires using a different syntax when printing assembly
output.

Instead of the usual syntax of '.section <name>,"dr",discard,<symbol>',
use '.section <name>,"dr"' + '.linkonce discard' (which is what GCC
uses for all assembly output).

This fixes PR38254.

Differential Revision: https://reviews.llvm.org/D49651

llvm-svn: 337756
2018-07-23 22:15:19 +00:00

117 lines
3.5 KiB
C++

//===- lib/MC/MCSectionCOFF.cpp - COFF Code Section Representation --------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/MC/MCSectionCOFF.h"
#include "llvm/BinaryFormat/COFF.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Support/raw_ostream.h"
#include <cassert>
using namespace llvm;
MCSectionCOFF::~MCSectionCOFF() = default; // anchor.
// ShouldOmitSectionDirective - Decides whether a '.section' directive
// should be printed before the section name
bool MCSectionCOFF::ShouldOmitSectionDirective(StringRef Name,
const MCAsmInfo &MAI) const {
if (COMDATSymbol)
return false;
// FIXME: Does .section .bss/.data/.text work everywhere??
if (Name == ".text" || Name == ".data" || Name == ".bss")
return true;
return false;
}
void MCSectionCOFF::setSelection(int Selection) const {
assert(Selection != 0 && "invalid COMDAT selection type");
this->Selection = Selection;
Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT;
}
void MCSectionCOFF::PrintSwitchToSection(const MCAsmInfo &MAI, const Triple &T,
raw_ostream &OS,
const MCExpr *Subsection) const {
// standard sections don't require the '.section'
if (ShouldOmitSectionDirective(SectionName, MAI)) {
OS << '\t' << getSectionName() << '\n';
return;
}
OS << "\t.section\t" << getSectionName() << ",\"";
if (getCharacteristics() & COFF::IMAGE_SCN_CNT_INITIALIZED_DATA)
OS << 'd';
if (getCharacteristics() & COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA)
OS << 'b';
if (getCharacteristics() & COFF::IMAGE_SCN_MEM_EXECUTE)
OS << 'x';
if (getCharacteristics() & COFF::IMAGE_SCN_MEM_WRITE)
OS << 'w';
else if (getCharacteristics() & COFF::IMAGE_SCN_MEM_READ)
OS << 'r';
else
OS << 'y';
if (getCharacteristics() & COFF::IMAGE_SCN_LNK_REMOVE)
OS << 'n';
if (getCharacteristics() & COFF::IMAGE_SCN_MEM_SHARED)
OS << 's';
if ((getCharacteristics() & COFF::IMAGE_SCN_MEM_DISCARDABLE) &&
!isImplicitlyDiscardable(SectionName))
OS << 'D';
OS << '"';
if (getCharacteristics() & COFF::IMAGE_SCN_LNK_COMDAT) {
if (COMDATSymbol)
OS << ",";
else
OS << "\n\t.linkonce\t";
switch (Selection) {
case COFF::IMAGE_COMDAT_SELECT_NODUPLICATES:
OS << "one_only";
break;
case COFF::IMAGE_COMDAT_SELECT_ANY:
OS << "discard";
break;
case COFF::IMAGE_COMDAT_SELECT_SAME_SIZE:
OS << "same_size";
break;
case COFF::IMAGE_COMDAT_SELECT_EXACT_MATCH:
OS << "same_contents";
break;
case COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE:
OS << "associative";
break;
case COFF::IMAGE_COMDAT_SELECT_LARGEST:
OS << "largest";
break;
case COFF::IMAGE_COMDAT_SELECT_NEWEST:
OS << "newest";
break;
default:
assert(false && "unsupported COFF selection type");
break;
}
if (COMDATSymbol) {
OS << ",";
COMDATSymbol->print(OS, &MAI);
}
}
OS << '\n';
}
bool MCSectionCOFF::UseCodeAlign() const {
return getKind().isText();
}
bool MCSectionCOFF::isVirtualSection() const {
return getCharacteristics() & COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA;
}