lib/MC/MCSectionCOFF.cpp

   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"
  15 using namespace llvm;
  16
  17 MCSectionCOFF::~MCSectionCOFF() {} // anchor.
  18
  19 // ShouldOmitSectionDirective - Decides whether a '.section' directive
  20 // should be printed before the section name
  21 bool 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
  31 void MCSectionCOFF::PrintSwitchToSection(const MCAsmInfo &MAI,
  32                                          raw_ostream &OS) const {
  33
  34   // standard sections don't require the '.section'
  35   if (ShouldOmitSectionDirective(SectionName, MAI)) {
  36     OS << '\t' << getSectionName() << '\n';
  37     return;
  38   }
  39
  40   OS << "\t.section\t" << getSectionName() << ",\"";
  41   if (getKind().isText())
  42     OS << 'x';
  43   if (getKind().isWriteable())
  44     OS << 'w';
  45   else
  46     OS << 'r';
  47   if (getCharacteristics() & COFF::IMAGE_SCN_MEM_DISCARDABLE)
  48     OS << 'n';
  49   OS << "\"\n";
  50
  51   if (getCharacteristics() & COFF::IMAGE_SCN_LNK_COMDAT) {
  52     switch (Selection) {
  53       case COFF::IMAGE_COMDAT_SELECT_NODUPLICATES:
  54         OS << "\t.linkonce one_only\n";
  55         break;
  56       case COFF::IMAGE_COMDAT_SELECT_ANY:
  57         OS << "\t.linkonce discard\n";
  58         break;
  59       case COFF::IMAGE_COMDAT_SELECT_SAME_SIZE:
  60         OS << "\t.linkonce same_size\n";
  61         break;
  62       case COFF::IMAGE_COMDAT_SELECT_EXACT_MATCH:
  63         OS << "\t.linkonce same_contents\n";
  64         break;
  65     //NOTE: as of binutils 2.20, there is no way to specifiy select largest
  66     //      with the .linkonce directive. For now, we treat it as an invalid
  67     //      comdat selection value.
  68       case COFF::IMAGE_COMDAT_SELECT_LARGEST:
  69     //  OS << "\t.linkonce largest\n";
  70     //  break;
  71       default:
  72         assert (0 && "unsupported COFF selection type");
  73         break;
  74     }
  75   }
  76 }
  77
  78 bool MCSectionCOFF::UseCodeAlign() const {
  79   return getKind().isText();
  80 }
  81
  82 bool MCSectionCOFF::isVirtualSection() const {
  83   return getCharacteristics() & COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA;
  84 }