MCSectionCOFF.cpp revision 251662
1//===- lib/MC/MCSectionCOFF.cpp - COFF Code Section Representation --------===// 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/MCSectionCOFF.h" 11#include "llvm/MC/MCAsmInfo.h" 12#include "llvm/MC/MCContext.h" 13#include "llvm/MC/MCSymbol.h" 14#include "llvm/Support/raw_ostream.h" 15using namespace llvm; 16 17MCSectionCOFF::~MCSectionCOFF() {} // anchor. 18 19// ShouldOmitSectionDirective - Decides whether a '.section' directive 20// should be printed before the section name 21bool MCSectionCOFF::ShouldOmitSectionDirective(StringRef Name, 22 const MCAsmInfo &MAI) const { 23 24 // FIXME: Does .section .bss/.data/.text work everywhere?? 25 if (Name == ".text" || Name == ".data" || Name == ".bss") 26 return true; 27 28 return false; 29} 30 31void MCSectionCOFF::PrintSwitchToSection(const MCAsmInfo &MAI, 32 raw_ostream &OS, 33 const MCExpr *Subsection) const { 34 35 // standard sections don't require the '.section' 36 if (ShouldOmitSectionDirective(SectionName, MAI)) { 37 OS << '\t' << getSectionName() << '\n'; 38 return; 39 } 40 41 OS << "\t.section\t" << getSectionName() << ",\""; 42 if (getKind().isText()) 43 OS << 'x'; 44 if (getKind().isWriteable()) 45 OS << 'w'; 46 else 47 OS << 'r'; 48 if (getCharacteristics() & COFF::IMAGE_SCN_MEM_DISCARDABLE) 49 OS << 'n'; 50 OS << "\"\n"; 51 52 if (getCharacteristics() & COFF::IMAGE_SCN_LNK_COMDAT) { 53 switch (Selection) { 54 case COFF::IMAGE_COMDAT_SELECT_NODUPLICATES: 55 OS << "\t.linkonce one_only\n"; 56 break; 57 case COFF::IMAGE_COMDAT_SELECT_ANY: 58 OS << "\t.linkonce discard\n"; 59 break; 60 case COFF::IMAGE_COMDAT_SELECT_SAME_SIZE: 61 OS << "\t.linkonce same_size\n"; 62 break; 63 case COFF::IMAGE_COMDAT_SELECT_EXACT_MATCH: 64 OS << "\t.linkonce same_contents\n"; 65 break; 66 //NOTE: as of binutils 2.20, there is no way to specifiy select largest 67 // with the .linkonce directive. For now, we treat it as an invalid 68 // comdat selection value. 69 case COFF::IMAGE_COMDAT_SELECT_LARGEST: 70 // OS << "\t.linkonce largest\n"; 71 // break; 72 default: 73 assert (0 && "unsupported COFF selection type"); 74 break; 75 } 76 } 77} 78 79bool MCSectionCOFF::UseCodeAlign() const { 80 return getKind().isText(); 81} 82 83bool MCSectionCOFF::isVirtualSection() const { 84 return getCharacteristics() & COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA; 85} 86