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/BinaryFormat/COFF.h"
  12 #include "llvm/MC/MCSymbol.h"
  13 #include "llvm/Support/raw_ostream.h"
  14 #include <cassert>
  15
  16 using namespace llvm;
  17
  18 MCSectionCOFF::~MCSectionCOFF() = default; // anchor.
  19
  20 // ShouldOmitSectionDirective - Decides whether a '.section' directive
  21 // should be printed before the section name
  22 bool MCSectionCOFF::ShouldOmitSectionDirective(StringRef Name,
  23                                                const MCAsmInfo &MAI) const {
  24   if (COMDATSymbol)
  25     return false;
  26
  27   // FIXME: Does .section .bss/.data/.text work everywhere??
  28   if (Name == ".text" || Name == ".data" || Name == ".bss")
  29     return true;
  30
  31   return false;
  32 }
  33
  34 void MCSectionCOFF::setSelection(int Selection) const {
  35   assert(Selection != 0 && "invalid COMDAT selection type");
  36   this->Selection = Selection;
  37   Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT;
  38 }
  39
  40 void MCSectionCOFF::PrintSwitchToSection(const MCAsmInfo &MAI, const Triple &T,
  41                                          raw_ostream &OS,
  42                                          const MCExpr *Subsection) const {
  43   // standard sections don't require the '.section'
  44   if (ShouldOmitSectionDirective(SectionName, MAI)) {
  45     OS << '\t' << getSectionName() << '\n';
  46     return;
  47   }
  48
  49   OS << "\t.section\t" << getSectionName() << ",\"";
  50   if (getCharacteristics() & COFF::IMAGE_SCN_CNT_INITIALIZED_DATA)
  51     OS << 'd';
  52   if (getCharacteristics() & COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA)
  53     OS << 'b';
  54   if (getCharacteristics() & COFF::IMAGE_SCN_MEM_EXECUTE)
  55     OS << 'x';
  56   if (getCharacteristics() & COFF::IMAGE_SCN_MEM_WRITE)
  57     OS << 'w';
  58   else if (getCharacteristics() & COFF::IMAGE_SCN_MEM_READ)
  59     OS << 'r';
  60   else
  61     OS << 'y';
  62   if (getCharacteristics() & COFF::IMAGE_SCN_LNK_REMOVE)
  63     OS << 'n';
  64   if (getCharacteristics() & COFF::IMAGE_SCN_MEM_SHARED)
  65     OS << 's';
  66   if ((getCharacteristics() & COFF::IMAGE_SCN_MEM_DISCARDABLE) &&
  67       !isImplicitlyDiscardable(SectionName))
  68     OS << 'D';
  69   OS << '"';
  70
  71   if (getCharacteristics() & COFF::IMAGE_SCN_LNK_COMDAT) {
  72     if (COMDATSymbol)
  73       OS << ",";
  74     else
  75       OS << "\n\t.linkonce\t";
  76     switch (Selection) {
  77       case COFF::IMAGE_COMDAT_SELECT_NODUPLICATES:
  78         OS << "one_only";
  79         break;
  80       case COFF::IMAGE_COMDAT_SELECT_ANY:
  81         OS << "discard";
  82         break;
  83       case COFF::IMAGE_COMDAT_SELECT_SAME_SIZE:
  84         OS << "same_size";
  85         break;
  86       case COFF::IMAGE_COMDAT_SELECT_EXACT_MATCH:
  87         OS << "same_contents";
  88         break;
  89       case COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE:
  90         OS << "associative";
  91         break;
  92       case COFF::IMAGE_COMDAT_SELECT_LARGEST:
  93         OS << "largest";
  94         break;
  95       case COFF::IMAGE_COMDAT_SELECT_NEWEST:
  96         OS << "newest";
  97         break;
  98       default:
  99         assert(false && "unsupported COFF selection type");
 100         break;
 101     }
 102     if (COMDATSymbol) {
 103       OS << ",";
 104       COMDATSymbol->print(OS, &MAI);
 105     }
 106   }
 107   OS << '\n';
 108 }
 109
 110 bool MCSectionCOFF::UseCodeAlign() const {
 111   return getKind().isText();
 112 }
 113
 114 bool MCSectionCOFF::isVirtualSection() const {
 115   return getCharacteristics() & COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA;
 116 }